Multiple medication use in the elderly. Use of prescription and non-prescription drugs in an Australian community setting. To document the extent of polypharmacy or multiple medication use in the elderly. Cross-sectional examination of an age cohort of a community. Community-based study in Dubbo, NSW, in 1988-1989. All non-institutionalised residents aged 60 years and over, numbering 1237 men and 1568 women. Assessment of use of prescription and non-prescription drugs, recent hospitalisation, years of education, psychosocial variables. 18% of men and 25% of women were currently using three or more classes of prescription drugs. The corresponding values for two or more classes of non-prescription drugs were 29% and 44%. Of those who were using multiple prescription drugs 56% of men and 76% of women were also using multiple non-prescription drugs. In a multiple logistic model, the following possible predictors of multiple drug use were included: hospitalisation in the last six months, age, sex, depression, life satisfaction and education. Multiple prescription drug use was significantly predicted by recent hospitalisation (odds ratio [OR] = 2.40; 95% confidence interval [CI], 1.63-3.56), increasing age (e.g. 70-79 years versus 60-69 years; OR = 2.54; CI, 1.97-3.25), female sex (OR = 1.59; CI, 1.25-2.01) and increasing depression (e.g. highest tertile of depression scale versus lowest; OR = 2.52; CI, 1.84-3.42). Multiple non-prescription drug use was significantly predicted by female sex (OR = 2.38; CI, 1.95-2.92) and increasing depression (OR = 2.77; CI, 2.16-3.56). For prescription items, non-prescription items, and both categories in combination levels of use 20% above the population average have been documented. Polypharmacy in the elderly population appears to be predicted by recent hospitalisation, increasing age, female sex and increasing depression. There is potential for drug-drug interaction to occur, but the findings suggest target areas for preventive action.


Intractable leg ulceration caused by cutaneous cholesterol embolism. To present a case of chronic intractable leg ulceration caused by cholesterol crystal embolism. A 76-year-old Caucasian male with a history of ischaemic heart disease had repeated hospital admissions for diagnosis and treatment of recurrent leg ulceration of more than three years' duration. Definitive diagnosis was made after the third biopsy when the specimen obtained included subcutaneous arteries. Complete healing occurred within three weeks of excision and a skin graft, and subsequent treatment which included systemic steroids. Cholesterol crystal embolism is probably an underdiagnosed cause of intractable leg ulceration and can be identified by a biopsy specimen which includes vessels in subcutaneous fat. Systemic steroids may be helpful in its treatment.


Severe botulism after eating home-preserved asparagus. To present a case of adult botulism acquired in Queensland. After eating home-preserved asparagus, a 33-year-old man presented with internal and external ophthalmoplegia, bilateral facial nerve palsies, and descending muscle weakness culminating in a sudden respiratory arrest. Electrophysiological testing demonstrated normal nerve conduction velocities and an incremental response of evoked motor potentials on repetitive stimulation, confirming the clinical diagnosis of botulism. Treatment with trivalent antitoxin, oral treatment with vancomycin and supportive mechanical ventilation for four weeks resulted in complete clinical recovery. Plasmapheresis was also used but its contribution to the patient's improvement is dubious. Although botulism is rare in Australia, clinicians should be aware of the clinical presentation and the rapidity of confirmation of the diagnosis by electrophysiological testing. Patients should be nursed in an intensive care setting. Regular testing of vital capacity should be performed to determine the need for mechanical ventilation.


Ellis-van Creveld syndrome in a Western Australian aboriginal community. Postaxial polydactyly as a heterozygous manifestation? To report two children with Ellis-van Creveld syndrome in an extended kindred of Western Australian Aboriginal descent. Furthermore, to document two family members with isolated postaxial polydactyly of the feet as probable heterozygous manifestations of the Ellis-van Creveld gene. Male and female second cousins with short limbs, postaxial polydactyly and cardiac malformations are described. It is proposed that founder effect and random genetic drift resulted in a relatively high frequency of the Ellis-van Creveld gene in the Aboriginal people of Western Australia. In addition, further evidence is provided for the postulate that isolated postaxial polydactyly is a heterozygous manifestation of the gene.


Pet ownership and risk factors for cardiovascular disease. To compare risk factors for cardiovascular disease in pet owners and non-owners. Accepted risk factors for cardiovascular disease were measured in 5741 participants attending a free, screening clinic at the Baker Medical Research Institute in Melbourne. Blood pressure, plasma cholesterol and triglyceride values were compared in pet owners (n = 784) and non-owners (n = 4957). Pet owners had significantly lower systolic blood pressure and plasma triglycerides than non-owners. In men, pet owners had significantly lower systolic but not diastolic blood pressure than non-owners, and significantly lower plasma triglyceride levels, and plasma cholesterol levels. In women over 40 years old, systolic but not diastolic pressure was significantly lower in pet owners and plasma triglycerides also tended to be lower. There were no differences in body mass index and self-reported smoking habits were similar, but pet owners reported that they took significantly more exercise than non-owners, and ate more meat and "take-away" foods. The socioeconomic profile of the pet owners and non-owners appeared to be comparable. Pet owners in our clinic population had lower levels of accepted risk factors for cardiovascular disease, and this was not explicable on the basis of cigarette smoking, diet, body mass index or socioeconomic profile. The possibility that pet ownership reduces cardiovascular risk factors should therefore be investigated.


Prospective audit of an aminoglycoside consultative service in a general hospital. To investigate the impact of the introduction of a consultative service on the use, efficiency of dosing and clinical toxicology of the aminoglycoside antibiotics, gentamicin and tobramycin, in a general hospital. Two audits were conducted six months and 18 months after the introduction of the consultative service. The audits reviewed the use of drug assay services, the adequacy of drug administration (as measured by serum antibiotic concentrations), indications for prescription, adverse outcomes (by noting markers of nephrotoxicity) and the antibiotic sensitivity of Gram-negative pathogens. The results were compared with the results of an audit conducted before the consultative service was instituted. There was a significant (P < 0.001 by chi 2 test) increase in the use of assays, with drug assays performed in 67% (first audit) and 77% (second audit) of aminoglycoside courses compared with 48.2% in the pre-intervention audit. Sample timing was greatly improved, with more than 70% of the samples collected at the appropriate times. Assay wastage in terms of uninterpretable assay results decreased significantly (P < 0.001) from 42.9% of total assays to 6.3% at the first audit and 3.8% at the second audit. The percentage of assay results in the desirable range increased significantly (P < 0.001) from 39.1% to 71.9% (first audit) and 75.4% (second audit). Pharmacokinetic recommendations were made in 39.1% and 64% of all aminoglycoside courses during the first and second audits respectively, with clinician acceptance of dosage recommendations at 83.1% and 82.8% respectively. For aminoglycoside courses prescribed for therapeutic reasons, 97.9% (first audit, n = 325) and 98.6% (second audit, n = 280) of indications for use were judged as clinically appropriate. The incidence of suspected aminoglycoside-induced nephrotoxicity was reduced from 8.9% of patients to 1.6% (first audit, P < 0.001) and 2.4% (second audit). Bacterial sensitivity audits showed that the great majority of clinical isolates of target organisms (n = 3523, Year 1 and n = 3385, Year 2) were sensitive to gentamicin (92.2% and 91.5% respectively) and tobramycin (98.1% and 98.8% respectively); these aminoglycosides exceeded all alternative agents in effectiveness, including first and third generation cephalosporins. The overall results indicate that introduction of the consultative service had a positive impact on the effective use of aminoglycosides, with a marked decrease in clinical toxicity. These influences were shown to persist for at least 18 months. The availability of reliable predictive techniques to reduce toxicity allows active promotion of aminoglycosides as the agents of choice on grounds of efficacy and economy.


The use of a videotaped questionnaire for studying asthma prevalence. A pilot study among New Zealand adolescents. To examine the feasibility of measuring asthma prevalence by means of an audio-visual presentation of asthma symptoms and signs (video questionnaire) and to compare this technique with a standard written questionnaire for predicting bronchial hyperresponsiveness. A cross-sectional study comparing the ability of a video questionnaire and a written, interviewer administered questionnaire to predict bronchial hyperresponsiveness. Bronchial responsiveness was measured with hand held nebulisers. Community survey of a New Zealand rural secondary school. A total of 456 adolescent school children aged 12-19 years (mean 15.5 years). Comparison of the sensitivity and specificity of a standard questionnaire versus a video questionnaire for bronchial hyperresponsiveness. The technique was easy to administer in the community setting. Overall sensitivity and specificity for the prediction of bronchial hyperresponsiveness were similar for the video and interviewer administered questionnaires. This new technique is easily used in the community setting, and gives predictions of bronchial hyperresponsiveness similar to those of a standard interviewer administered questionnaire. Further examination of the technique in comparisons of asthma prevalence among different populations is planned.


Acute gastrocnemius myositis. Another extraintestinal manifestation of Crohn's disease. To present the first case in Australia of skeletal muscle inflammation as a manifestation of Crohn's disease. A 50-year-old man was admitted to hospital with a two-week history of bloody diarrhoea, weight loss of 3 kg, soreness of his calf and thigh muscles, and night sweats. A clinical diagnosis of acute Crohn's gastrocnemius myositis was made. Muscle biopsy was not performed. He was prescribed hydrocortisone by the intravenous route, which was replaced by prednisone by mouth. The myositis resolved completely within 48 hours. Corticosteroids are an effective treatment for this rare extraintestinal manifestation of Crohn's disease. Invasive investigations can be reserved for those who fail to respond.


Pulmonary oedema--prehospital treatment. Caution with morphine dosage. To inform doctors of potential hazards if opioids are administered in excessive doses to patients with acute pulmonary oedema. Three elderly patients were unresponsive and hypotensive on arrival in the emergency department. All had received morphine parenterally as a component of prehospital treatment for acute pulmonary oedema. All were given naloxone intravenously, regained consciousness and had a rise in blood pressure. Parenteral administration of opioids should be used with caution in acute pulmonary oedema. The authors present a protocol for prehospital drug therapy.


Eosinophilic fasciitis associated with L-tryptophan ingestion. To present the first case of eosinophilic fasciitis associated with L-tryptophan ingestion. A 23-year-old Australian man developed myalgia and weakness, and later the clinical features of eosinophilic fasciitis, while taking L-tryptophan. The amino acid supplementation was discontinued and he was treated with prednisone (30 mg/day) for six weeks with significant improvement. In sclerodermatous skin diseases, such as eosinophilic fasciitis, the possibility of ingestion of tryptophan-containing products should be considered.


Successful treatment of disseminated strongyloidiasis. To report the successful treatment of Strongyloides stercoralis hyperinfection, which is usually lethal but in this case was diagnosed in its early stages. A 44-year-old woman, who had spent much of her life in Fiji and India, was treated with a high dose of prednisolone for rheumatoid arthritis complicated by gold lung. The onset of abdominal symptoms, an exacerbation of respiratory symptoms, and a persistent high eosinophil count and serum IgE level, led to the detection of numerous Strongyloides larvae in her faeces and sputum. She was treated with thiabendazole for five days, then mebendazole for one month, and the dose of prednisolone was reduced. Clinical symptoms and signs improved within days and after one week parasites could not be found in her faeces. After six months, enzyme-linked immunosorbent assay for Strongyloides infection gave a reading which was 40% of the initial level but still in the positive range. Steroid therapy in individuals with chronic, subclinical strongyloidiasis predisposes to the insidious development of hyperinfection syndrome, which has a high mortality rate. If detected early, this complication can be treated effectively. It can be prevented by actively seeking Strongyloides infection, by faecal microscopy and culture techniques and by serological tests, in high-risk individuals, such as immigrants from endemic areas.


Human albumin solutions: consensus statements for use in selected clinical situations. Subcommittee of the Victorian Drug Usage Advisory Committee. To establish consensus statements for the use of human albumin solutions in clinical situations identified as responsible for the major use of human albumin products. Working parties comprised of specialists in intensive care, renal medicine, cardiothoracic anaesthesia, gastroenterology, haematology and transfusion medicine, were convened to develop consensus statements for the use of human albumin solutions. Specific statements have been formulated to guide the clinician in the use of human albumin solutions for hypovolaemia or hypoalbuminaemia (particularly in intensive care units), cardiothoracic surgery, therapeutic plasma exchange and patients with ascites or protein-losing states in gastroenterology. These statements, with wide dissemination, will promote consistency in the use of human albumin products in clinical practice and become a reference for future audits on the use of these products.


Origin of mineral crystal growth in collagen fibrils. Collagen fibrils from young turkey-leg tendons, just beginning to mineralize, were stained with uranyl acetate and examined by electron microscopy. Small needle-like mineral crystals were observed and located, in relation to the collagen banding pattern, as originating at the e band in the gap region and near the surface of the fibrils. These are evidently the sites of crystal nucleation. They lie near binding locations on collagen fibrils of two glycosylated proteins believed to be implicated in the mineralization process, as well as the sites of early crystals in embryonic fowl bones.


Self-assembly into fibrils of a homotrimer of type I collagen. Type I collagen, the most abundant structural protein in vertebrates, is comprised of two alpha 1(I) chains and one alpha 2(I) chain. Fibroblasts from a proband with osteogenesis imperfecta, however, were shown to synthesize a type I procollagen that was a homotrimer of pro alpha 1(I) chains. The absence of pro alpha 2(I) chains in the procollagen provided a unique opportunity to assess the role of the alpha 2(I) chain in collagen fibrillogenesis by examining the self-assembly de novo of the homotrimeric collagen generated in vitro. The results demonstrated that the fibrils formed by the homotrimeric collagen had an asymmetric banding pattern similar to fibrils of normal heterotrimeric type I collagen. However, the efficiency for self-assembly of the homotrimer into fibrils was markedly reduced in that the critical concentration at 37 degrees C was 40-fold greater than for self-assembly of the heterotrimeric molecule. A van't Hoff-type plot of the data was used to determine values for delta G, delta H and delta S. The values indicated the self-assembly of the homotrimer is similar to self-assembly of the heterotrimer in that the process is entropy driven. The process is, however, less favorable in that the delta G value was 10 kJ/mol less negative. The results suggest that the presence of the alpha 2(I) chain in type I collagen helps drive the self-assembly process, probably because the alpha 2(I) chain is more hydrophobic than the alpha 1(I) chain and, therefore, smaller amounts of structured water may be lost during self-assembly of the homotrimer than during self-assembly of the heterotrimer.(ABSTRACT TRUNCATED AT 250 WORDS)


Inhibition of calcification in vivo by acyl azide cross-linking of a collagen-glycosaminoglycan sponge. A collagen-glycosaminoglycan sponge composed of collagen (80%), chondroitin-4-sulfate (13.3%) and heparan sulfate (6.6%) was cross-linked using the acyl azide method or glutaraldehyde (0.0075%). Under optimal conditions, the denaturation temperature (Td) was raised to 69 degrees C (+23 degrees C) for the sponge treated by the acyl azide method and to 68 degrees C (+22 degrees C) for that treated with glutaraldehyde. The biocompatibility of the treated and control sponges was studied up to 3 months after subcutaneous implantation in rats by analysing cellular responses and calcification by histological and ultrastructural methods. A control collagen-glycosaminoglycan sponge was rapidly invaded by mononuclear cells (8 days), with the formation of granulation tissue. Calcification was observed at the periphery of the implant after 8 days, and the implant was entirely calcified after 15 days; it was degraded progressively after 30 days. Acyl azide treatment increased the persistence of the sponge in vivo up to 90 days and inhibited its calcification. A glutaraldehyde-treated sponge was completely calcified after 15 days, and calcified nodules persisted after 90 days. Thus, acyl azide method efficiently cross-linked a collagen-glycosaminoglycan sponge and inhibited calcification after subcutaneous implantation in rats (at least up to 90 days after implantation).


Endochondral ossification and de novo collagen synthesis during repair of the rat Achilles tendon. Ectopic endochondral ossification is the inevitable consequence of midpoint tenotomy of the rat Achilles tendon. After tenotomy, the tendon stumps retract and the intervening space fills with granulation tissue. The initiation of chondrogenesis is indicated by pre-chondrocytic cells forming a "whorled" pattern, both at the tendon stumps and within the granulation tissue and later clearly differentiating into cartilage nodules. The chondrocytes rapidly "hypertrophy" exhibiting an orientation similar to that in epiphyseal growth plates. The nodules of cartilage are then replaced, by bone. During this total process, a temporal and spatial pattern of new collagen synthesis can be demonstrated, both biochemically and immunocytochemically. Both the cartilage and the subsequent bone closely resemble the tissue in developing long bones enabling this model to be used to study the initial switching on of normal chondrogenesis and osteogenesis in a system not normally programmed to do so.


Production of both 92- and 72-kDa gelatinases by bone cells. We investigated the ability of murine bone organ cultures and osteoblast-like bone cells to produce 72- and 92-kDa gelatinase. 4-6 day newborn mouse calvaria cultures were found to release gelatinase activity into their conditioned medium (CM). This activity was increased by four stimulators of resorption, tumor necrosis factor alpha (TNF), interleukin-1 alpha (IL-1), parathyroid hormone (PTH) and the active phorbol ester, 12-O-tetradecanoylphorbol-13-acetate (TPA). Both the 72- and 92-kDa forms of gelatinase were produced by murine bone cultures. In unstimulated bones 72-kDa gelatinase activity was approximately equal to that of the 92-kDa enzyme. IL-1, TNF, PTH and TPA all increased 92-kDa gelatinase activity in the CM of the bone cultures by about 2- to 2.5-fold. In addition TPA and IL-1 also increased 72-kDa gelatinase activity. In unstimulated osteoblast-like MC3T3-E1 cell cultures 72-kDa gelatinase enzyme activity was much greater than 92-kDa activity and was not substantially regulated (less than 40% change) by IL-1, TNF or PTH. In contrast, these agents stimulated 92-kDa gelatinase activity by 2- to 5-fold. As with the MC3T3-E1 cells, primary cells constitutively produced both 72-kDa and 92-kDa gelatinase. This was true for cells with both the most differentiated osteoblast-like phenotype (populations 3 and 4) and the least osteoblast-like phenotype (populations 1 and 2). In unstimulated cultures of all 4-primary populations, 92-kDa gelatinase production was less than 72-kDa and IL-1, TNF and PTH had only small effects on 72-kDa production in any of the populations (less than 60% change).(ABSTRACT TRUNCATED AT 250 WORDS)


Age-related changes in the concentration of hydroxypyridinium crosslinks in functionally different skeletal muscles. High-performance liquid chromatography methods were developed to measure the concentration of hydroxypyridinium crosslinks in the intramuscular collagen and tendinous parts of functionally different skeletal muscles at different ages. A significant increase in pyridinoline concentration took place during maturation reaching 0.32 +/- 0.07 (mol/mol collagen) in soleus (slow plantar flexor) and 0.28 +/- 0.07 in plantaris (fast "mixed" plantar flexor) at the age of 4 months. In medial and lateral gastrocnemius (fast "mixed" plantar flexors) the pyridinoline concentrations (mol/mol collagen) reached 0.24 +/- 0.06 and 0.19 +/- 0.04, respectively, similar to those in both the extensor digitorum longus (fast "mixed" dorsi flexor) and rectus femoris (fast "mixed" knee extensor) muscles, but higher than in the fast "mixed" dorsi flexor muscle, anterior tibialis (0.11 +/- 0.05 mol/mol). By comparison, pyridinoline concentrations of 0.33 mol/mol collagen (+/- 0.10) was measured from longissimus dorsi, a slow-twitch back posture muscle. After maturation the most significant increase in pyridinoline concentration was measured in soleus and gastrocnemius muscles. No differences in the crosslinking between different parts of muscle belly were noticed at any time-point. However, significantly fewer pyridinoline crosslinks were found in tendinous parts of soleus, extensor digitorum longus and anterior tibialis than in intramuscular collagen. The concentration of pyridinoline crosslinks tended to be highest in slow-twitch postural muscles, soleus and longissimus dorsi, and generally higher in plantar flexors which are exposed to higher stretch than dorsal flexors. The reasons for the unexpectedly low concentrations of pyridinoline crosslinks in the tendinous parts of muscles remain to be clarified.


Studies of collagen in bone and dentin matrix of a Columbian mammoth (late Pleistocene) of central Utah. A Columbian mammoth, Mammuthus columbi, was excavated at an elevation of 9000 feet in Huntington Canyon, Emery County, Utah. Radiocarbon dates on the skeleton indicated death approximately 11,200 years ago. The skeleton was removed from postglacial, Late Quaternary, lake sediments deposited as glacial runoff approximately 9500 years ago. The bones and teeth were especially well preserved in a saturated lake bed. After excavation the bones and teeth were preserved by controlled desiccation, without hardeners, over a period of 9 months. Microradiography, light and electron microscopy, medium and high angle X-ray diffraction, amino acid analysis and cyanogen bromide peptide mapping were undertaken to evaluate the packing, organization, and preservation of collagen in bone and dentin of this mammoth. Microradiography and light microscopy showed that the bone consisted of especially well preserved compact and trabecular bone, and electron microscopy of demineralized bone and tusk showed that the matrix consisted of lamellae of densely packed cylindrical collagen fibrils. Cell remnants with intact nuclei, with or without a nucleolus, as well as variable lengths of plasma membrane were occasionally present on the surface of bony trabecula. Remnants of odontoblast processes were present in some dentin tubules. High and low angle X-ray diffraction demonstrated that the demineralized matrix contained native collagen molecules and amino acid analysis showed that the composition was comparable to that of type I collagen. Cyanogen bromide peptide mapping indicated that the major peptides of type I collagen were present and had the same electrophoretic mobility as that of type I collagen of demineralized Asian elephant bone and rat tail tendon.(ABSTRACT TRUNCATED AT 250 WORDS)


Proteoglycan synthesis in normotensive and spontaneously hypertensive rat arteries in vitro. Proteoglycans (PGs) were analyzed and compared in the media of the thoracic aorta, abdominal aorta, left carotid artery and superior mesenteric artery of age-matched Wistar-Kyoto (WKY) and spontaneously hypertensive (SHR) rats. Two ages were examined; 10 week old, during the development of hypertension and 28 week old, when hypertension is well established in the SHR. Large chondroitin sulfate PG, large heparan sulfate PG and biglycan (PGI) and decorin (PGII) small PGs were identified. Biglycan was the predominant small PG found in all arteries. Newly synthesized PGs were labelled in vitro with 35SO4 for quantitation. The synthesis of large and small PGs was similar in the media of the thoracic aorta, abdominal aorta, left carotid artery, and superior mesenteric artery. The large to small ratio value, a measure of the artery PG composition, was also similar among the four arteries but was highest in the mesenteric artery. In both WKY and SHR arteries there was significantly decreased PG synthesis in the 28-week old compared to 10-week old animals. This was especially true for large PG. Hypertensive changes in PG synthesis were seen mainly in the carotid artery. In this artery, synthesis of both large and small PG was increased in the SHR, at both ages. The ratio of large to small PG was not significantly different between SHR and WKY arteries. We conclude that 28-week old WKY and SHR rat arteries synthesize less large and small PG than 10-week old arteries. The most prominent change seen in hypertensive rats is an increase in PG synthesis in the carotid artery.


In-situ hybridization of tropoelastin mRNA during the development of the multilayered neonatal rat aortic smooth muscle cell culture. Cultured neonatal rat aortic smooth muscle cells are active in synthesizing and depositing large amounts of elastin in their extracellular matrix, making this an ideal system for studying elastogenesis. In this study, the ability of individual cells to synthesize tropoelastin was examined by in-situ hybridization methods. One-micron semi-thin epoxy resin-embedded transverse sections of cells cultured 1, 2, 3 and 4 weeks showed an increase with time in both the number of cells with hybridization signal and the signal intensity; tropoelastin mRNA hybridization signal intensity decreased thereafter up to 8 weeks in culture. In longitudinal sections through the early cultures (1-week), we observed mitotic cells with no detectable hybridization signal, and non-mitotic cells with either no, little or high signal intensity. These data suggest that mitotic cells do not synthesize tropoelastin, and that there is a strong correlation between the hybridization signal intensity and the rate of tropoelastin synthesis. These data also suggest in-situ hybridization methods can detect which cell(s) contain tropoelastin mRNA, their location in the multilayer, and variations in signal intensity. We conclude it is possible to correlate hybridization signal intensity with variations of tropoelastin mRNA levels within individual cells of the cultured smooth muscle cell multilayer.


The group A streptococcal M-type 3 protein gene exhibits a C terminus typical for class I M proteins. The M protein gene (emm gene) from a reference group A streptococcal strain of serotype M3 was amplified by the polymerase chain reaction and partially sequenced. Hybridization assays using an oligonucleotide probe derived from the N-terminal sequence revealed that this gene segment is highly homologous among M-type 3 isolates. Of note, analysis of the nucleotide sequence data from the C terminus of the gene confirmed that the emm 3 gene exhibited all the features characteristic for group A streptococcal M-class I molecules. Recently published sequence data that were assigned to emm 3 resulted from a strain confusion and were shown to be the first one derived from an emm gene of an M-untypable isolate.


Ubiquitous occurrence of virR and scpA genes in group A streptococci. Until now a few serotypes of M-class I group A streptococci (GAS) have been shown to encode VirR, a positive regulatory factor for the coordinate expression of the M protein (emm) and C5a peptidase (scpA) genes. The polymerase chain reaction technique has been applied to the genomic template of 36 GAS serotypes to demonstrate the general presence of VirR (virR) genes and scpA in GAS of both M classes. A virR gene region conserved in size was demonstrated for every strain investigated. Differences between virR genes from GAS of the two M classes were mainly confined to the 3' end of the gene and a region upstream of the gene's promoter. Every M-class II strain and some M-class I isolates were shown to possess a scpA gene of 4.6 kb, the rest of the M-class I GAS harbors a 3.5-kb scpA gene. The additional segment of 1.1 kb in the large-size scpA genes was located within a region of direct repeats at the 3' end of the gene. Among the serotypes encoding a large-size scpA gene a minority exhibits additional sequence variation downstream of the region of direct repeats.


Recombinant human granulocyte-macrophage colony-stimulating factor in children with chemotherapy-induced neutropenia. Twenty children 1-17 (median, 5.5) years of age received GM-CSF during chemotherapy-induced neutropenia at the dose of 5 micrograms/kg/day, continued until the absolute neutrophil count (ANC) exceeded 500 x 10(6)/liter. Twelve children with solid tumors received GM-CSF after courses of conventional chemotherapy (VP-16 + ifosfamide or "6 in 1"). One course followed by GM-CSF was compared to identical courses without GM-CSF in the same patients. Eight children with recurrent/poor risk malignancies received GM-CSF after marrow-ablative therapy and autologous bone marrow transplantation (ABMT). Their engraftment data were compared to matched historical controls. In both groups GM-CSF accelerated myeloid recovery, which was preceded by the appearance of immature myeloid elements in bone marrow. The ANC levels of 200, 500, and 1,000 x 10(6)/liter were exceeded 2, 3 (P < 0.05), and 6 (P < 0.005) days earlier with GM-CSF in the conventional chemotherapy group, and 6, 10 (P < 0.05), and 9 days earlier in the ABMT group, as compared to the controls. All adverse effects observed were mild, including skin rashes, nasal stuffiness, general achiness, nausea, and fever. We conclude that GM-CSF is well tolerated in children and accelerates myeloid recovery in chemotherapy-induced neutropenia.


Minimal requirements for the diagnosis, classification, and evaluation of the treatment of childhood acute lymphoblastic leukemia (ALL) in the "BFM Family" Cooperative Group. Minimal requirements and their rationale for the diagnosis and the response to treatment in childhood acute lymphoblastic leukemia (ALL) were defined in the recently instituted "BFM-Family"-Group, in which the German, Austrian, Dutch, Italian, Belgian, French and Hungarian childhood leukemia study groups cooperate. ALL is defined as > or = 25% lymphoblasts in the bone marrow; for confirmation of the diagnosis and classification the criteria of the French-American-British (FAB) criteria are retained. For determination of the extent of the disease at diagnosis or relapse the criteria by the Rome Workshop [1986] are recommended: An obligatory panel of monoclonal antibodies for immunophenotyping was defined, as well as criteria for precursor B-ALL and T-ALL. Cytogenetic studies may support the diagnosis and subtyping, and are essential to identify certain patients with a high risk of treatment failure (f.i. t(9;22), t(4;11)). The role of molecular genetics for the diagnosis and the characterization of leukemia and the value of its clinical application needs further elucidation. Relapse was defined as recurrence of evident leukemia in the blood, bone marrow (> or = 25% lymphoblasts) or at any other site (to be confirmed by histological examination). Bone marrow involvement combined with extramedullary relapse was defined as > or = 5% lymphoblasts in the bone marrow.


Primary skeletal non-Hodgkin's lymphoma in the pediatric age group. The authors discuss rare primary skeletal non-Hodgkin's lymphoma in 16 patients treated from 1973 to 1989. The symptoms of these patients related to bone lesions in 95% of the cases. These bone lesions were monostotic or polyostotic, with or without regional and distant metastases. The locations of these lesions were long bones in 13 patients, pelvic bones in seven patients, and skull and vertebral bodies in two patients. The anatomical locations of these lesions in the bones were diaphysis alone in one patient, epiphysis in two patients, metaphysis in three patients, and a combination of diaphyseal, epiphyseal, and metaphyseal lesions in seven patients. Extraskeletal involvement was present in nine patients; extraskeletal sites included regional or distant lymph node involvement in seven cases, the mediastinum in two, lung nodules in two patients, the skin and subcutaneous regions in four patients; bone marrow in three patients, and peripheral nervous system (PNS) in one patient. Two patients had stage I disease, three had stage II disease, eight had stage III disease, and three had stage IV disease. The majority of patients had large noncleaved cell diffuse lymphomas or DHL by Rappaport classification. All patients were treated with the LSA2-L2 protocol; six patients received radiation therapy to the affected bone, and ten patients received no radiation therapy. Three patients failed on treatment within the first 4 months of therapy. Two patients developed a second tumor, one in the radiation therapy field and the other in a patient who received no radiation therapy.(ABSTRACT TRUNCATED AT 250 WORDS)


Recurrent cerebrovascular accident with L-asparaginase rechallenge. We report a 15-year-old boy diagnosed with acute lymphoblastic leukemia (ALL) in 1983. Induction therapy included L-asparaginase. After the second dose of L-asparaginase, he had a left sided focal seizure and computed tomography (CT) scan of the head showed a right frontal infarct. No further L-asparaginase was given. Complete remission was achieved and he successfully completed therapy in 1986. Eight months later he had an isolated bone marrow relapse. Reinduction therapy included L-asparaginase. After the fourth dose of L-asparaginase, he presented with severe headache and a CT scan showed a right temporal infarct. Repeat infarction on rechallenge with L-asparaginase has not been previously reported. Prophylactic therapy, such as fresh frozen plasma, should be considered before patients, with a previous cerebral insult, are rechallenged with L-asparaginase. However the effectiveness of such therapy has not been established.


[The characteristics of the intrathoracic complications of suppurating echinococcal liver cysts]. Using the material from 48 patients with intrathoracic complicated festered liver echinococcus cysts, the variations of break and the localization of connections between festered liver echinococcus cysts and thoracic organs were characterized. The pathological processes in the organs of the pleural cavity were described. A classification of intrathoracic complications proposed by the authors permits one to avoid diagnostical and tactical mistakes and to decrease human mortality.


[The characteristics of the clinical course of hydatid pulmonary echinococcosis in the native inhabitants of Chukotka]. 23 patients with pulmonary hydatid disease were observed in Chukotka. The patients observed were divided into 2 groups (14 and 9 patients) matched for sex, age, invasion intensity and topography. The patients of the first group were operated after they had been diagnosed, and the patients of the second group were observed without operation. In the both groups, the symptoms of invasion were low expressive, its course was torpid, the complications were rare and the dissemination was not recorded. Two patients observed without operation recovered after the break of the cyst into the bronchus and its evacuation. Relapses of invasion after operation were not recorded in any case. The causes of the good clinical course of pulmonary hydatid disease in the aborigines of Chukotka and the necessity of revising the treatment course are discussed.


[Natural foci of trichinelliasis in the Caspian Sea area]. The formation of natural foci of trichinelliasis was shown to depend on the established biocenotic relations between carnivorous animals. A highly intensive transmission of the invasion was recorded in continental areas where predators suffer from the lack of food in winter. Identification of the isolated Trichinella samples using single-pair cross hybridization and isoenzyme identification methods showed that the parasites of predators are T. spiralis nativa on the Northern Caspian coast and T. s. nelsoni on the Southern coast.


[Trichinelliasis in southern Ukraine].

[Trichinelliasis in southern Ukraine]. The analysis of literature data and the authors' own investigations showed that the southern part of the Ukraine is a trichinelliasis endemic territory where the synanthropic foci of the invasion are registered. The wide spreading of trichinelliasis among pigs and the nonobservance of the control measures provided by the veterinary legislation cause an increase in human prevalence.


[A morphometric study of the bone marrow of mice infected with Trichinella spiralis and T. pseudospiralis]. The study of cytograms of the marrow of mice with experimental T. spiralis and T. pseudospiralis invasion of 1 to 60 days revealed the marked activation of granulocytes and lymphoid cell proliferation with the much lower response of erythroid cells. The maximal response occurred at 21-35 days of invasion with subsequent diminution. In mice experimentally invaded with T. pseudospiralis the response of the marrow was less pronounced, but the period of active cell proliferation was prolonged.


[Intestinal trematodiases (metagonimiasis, nanophyetiasis): clinico-parasitological research and the first trial of using Azinox in a focus of the lower Amur River valley]. A focus of metagonimiasis and nanophyetiasis is described with the average human prevalence of 66.7 and 4.2%, respectively and low intensity of invasions (less than 100 eggs per 1 g). Metagonimiasis and nanophyetiasis are clinically expressed as chronic enterocolitis. A high effect of a single dose 10 mg/kg of azinox against metagonimiasis (98%) and nanophyetiasis (100%) was shown. The treatment course was proved to be useful in the foci of the Amur basin.


[Trichinelliasis in the wild and domestic animals of Kamchatka Province]. The results of many years' observations and literature data allowed one to determine the species of wild and domestic mammalians, vectors of trichinelliasis in Kamchatka. The variability of trichinelliasis prevalence in individual mammalian species were found in relation to their habitation place. Significant fluctuations of the index are presented by years. Cases of trichinelliasis in wild American minks (acclimatized species) and in pigs were noted.


[The infectivity of the population with the tapeworm Diphyllobothrium klebanovskii in an area of infection drift in the Khabarovsk Territory]. Copro-ovoscopic survey of the human population in the Khabarovsk Territory and the analysis of data of account of territorial sanitary epidemiological station showed that people invaded with D. klebanovskii are registered only in areas whose rivers catadromous salmon come to spawn. Most of invaded people are recorded on the seashore. The risk of tapeworm invasion and the epidemiological characteristics of the carry-over zone are discussed.


[The role of national meat dishes in infecting the population of Azerbaijan with taeniarhynchiasis]. The survival of taeniorhynchus cysticerci in 12 national meat dishes was studied in Azerbaijan. It was shown that in 7 dishes (sulu hinghal, suzma hinghal, kutab, gyurza, dushbara, dolma, tavah-kebob) the cysticerci died at suitable temperature and continuous cookery treatment. But in the mutton roasted on spits, lulah kabob, kyufta, kutaby and some other dishes 5.7 to 82% of cysticerci survive, and the dishes might be a danger as factors of transmission.


[The search for new antiparasitic agents. 11. The acute toxicity and anticestodal activity of the new anthelmintic Tizanox compared with Azinox]. A synthesis is described and the results of toxicological trial of the potential anthelmintic agent G-1587 are presented. The agent is 2-(cyclohexylcarbonyl)-1,2,3,6,7,11b-hexahydro-2H-[1, 2,5] thiadiazino [3,2-a] isoquinoline-4,4-dioxide. The agent was shown to have a low toxicity, the maximal sublethal dose for mice being 4.0 g/kg when given per os.


[An improved complex of measures to prevent enterobiasis]. Enterobiasis is the most common helminth in the USSR. Despite of its clinical manifestations in children, some parents do not see a doctor. 105 parents were interrogated by questionnaires. 71% of them called the reason why they had taken no medical advice and the rest evaded the question. The parents' questionnaire is an important measure for preventing and controlling enterobiasis with regard to better health education methods used in the work with parents and tutors from pediatric institutions.


[The sanitary-epidemiological assessment of the enterobiasis situation and its prevention in children's institutions in new buildings]. A complex plan of enterobiasis control measures for a sharp and stable decrease of the prevalence level at nursery schools in new buildings is presented. This complex plan allows one to reduce the extent of investigations 3-4-fold. A trial of the complex plan proposed on territories with foci of different types should be expedient with its subsequent introduction into the practice.


[Enzymes of the peripheral blood leukocytes from the vertebrate host in an experimental Leishmania infection. 1. Neutrophil acid phosphatase]. The results of cytochemical identification of acid phosphatase in the neutrophils of mice, guinea pigs and golden hamsters inoculated with leishmanial promastigotes of different species and virulence and also of people vaccinated against zoonotic cutaneous leishmaniasis are presented. The reversible increase of the enzyme activity in host's blood neutrophils and its dependence on parasite species and virulence are shown.


[The serological examination of the population for leishmaniasis and the detection of Leishmania in rodents in the Republic of Guinea]. A serological study on leishmaniasis in human population of Guinea revealed the percentage of seropositive persons varying in different parts of the country from 0.84 to 4.76 (according to C-ELISA) and from 1.0 to 5.1 (according to IFAT). The majority of sera positively reacting in C-ELISA with the antigen of Leishmania major in dilutions of 1:800 and higher were received from Kundara District (northwestern part of the country), and with the antigen of L. donovani sensu lato from Sigiri and Kankan districts (northeastern part of the country). All the districts were situated in the savanna zone. The amastigotes of Leishmania were found in the liver and spleen of Tatera gambiana caught near Kindia. These data suggest the circulation of Leishmania over the territory of Guinea.


[The surveillance of anthropogenic influence on the environment in intestinal parasitoses]. The necessity of anthropogenic influence control system as a component of the system of antiparasitic measures is proved. "System of anthropogenic influence control" proposed by the authors includes the complex of juridical and scientific methodological supply, the subsystem of sanitary parasitological monitoring, the subsystem of measures for environmental protection and sanitation and laboratory control. The use of the system in practice might allow one to increase the efficacy of environmental protection and parasitic disease prophylaxis measures.


[The division of the territory of Azerbaijan into districts by hydatid echinococcosis]. The epizootiological and epidemiological stratification of the territory of Azerbaijan on hydatid disease was made. Four zones were identified as low, moderately, highly and extremely endemic. These zones are differentiated from their climatic and social conditions for echinococcosis distribution, human incidence and prevalence, canine and ovine number and prevalence, and the time of survival of echinococcus eggs in the soil. The most intensive disease control measures are recommended in mountainous regions of the Small Caucasus.


[The variability of the itch mite Sarcoptes scabiei De Geer (Acariformes, Sarcoptidae) in connection with the epidemiology of scabies. A rank system for the variability of the chaetoid integument in females]. The variability of the naked section of the chaetoid cover of itch mite Sarcoptes scabiei De Geer females was studied. The sample used was divided into 5 grades by the number of undeveloped chaetoids. The structures surrounding the naked section, its size and dimensions of the female body were analysed in each grade of specimens. Such grade scale for describing the chaetoid cover proved to be useful for comparative analysis of human and animal forms of itch mite.


[The importation of malaria from Afghanistan into the USSR (a retrospective analysis of data from epidemiological surveys of cases and foci during 1981-1990)]. A retrospective analysis of imported malaria due to military operations revealed the main regularities in the behaviour of Plasmodium vivax population and the relationships between the imported parasite and the native Anopheles species. High percentage of cases with protracted incubation was noted in soldiers after their home-coming; the clinical symptoms were often registered 7-12 months after return. No epidemic consequence of imported and introduced cases of tertian malaria in malariogenic areas was shown. The effect of mass drug administration in military contingents was proved to be low due to irregular use of drugs or their discontinuance. The import of carriers to malariogenic areas was found to cause a minimal risk of restoration and implantation of tertian malaria. The current epidemiological monitoring system was shown to be rather effective for maintaining the epidemiological prosperity in the country.


[The feeding characteristics of mosquito larvae of the genus Anopheles]. Studies carried out on 6 species of malaria mosquitos revealed a relationship between the larval activity to scratch the substrate and their morphological and physiological features and also their development at different depth of feed immersion. The development of scratching capacity was compared in different species of Anopheles and Cellia subgenera.


[Antibody detection in zoonotic cutaneous leishmaniasis by using the indirect immunofluorescence reaction and C-ELISA in different clinical manifestations of the disease]. 189 sera from patients with ZCL of different stages were studied by means of RNIF and C-ELISA. A high significant correlation between RNIF and C-ELISA indices was shown, but the latter test was proved to be more sensitive and therefore more effective. In patients with ZCL, a significant direct correlation between the duration of the process and the antibody titer was established by means of C-ELISA. In patients with ZCL at the third (final) stage (reduction and granulation of lesions), the C-ELISA liter of specific antibodies was higher than at the second stage (rapidly progressing ulceration of lesions). The findings indicate the presence of clinical and serological parallels in ZCL and show it expedient to compare the dynamics of antibody genesis and cell immunity indices in further studies.


[Observations on malaria vectors in Mozambique. I. The status of Anopheles populations before the start of mosquito control]. The basic status parameters of populations of the main malaria vectors (Anopheles arabiensis and An. funestus) in the vicinity of the city of Maputo, Mozambique, were considered, such as mosquito density and its seasonal variation, female biting activity rate, degree of mosquito-man contact, degree of exophilia and endophagy, physiological age of females, duration of gonotrophic cycle, sporozoite index, vectorial capacity, entomological inoculation rate.


[A trial of the possible joint use of mermithids and bacterial preparations for the control of mosquito larvae]. The action of bacterial insecticides based on Bacillus thuringiensis H-14 and B. sphaericus in a dose of 0.005-2 mg/l on the mermithids Romanomermis iyengari, R. culicivorax and R. jingdeensis was studied. It was shown that though bacterial agents suppressed mermithid preparasite larvae density about 30-40%, the survivors might invade 100% of mosquito larvae. The viability and fertility of adult mermithids did not change under the influence of bactoculicide in doses 5-50 times higher than those used against mosquitoes in practice. In combined field trials of sphaerolarvicide (1.5 kg/ha) and R. iyengari mermithids the infectivity of Anopheles sacharovi larvae reached 96%. Mermithids in combination with bactoculicide and sphaerolarvicide might be useful in integrated control systems because these bacterial agents are harmless for mermithids of all stages in doses useful against mosquito larvae.


[Insecticide resistance and irritability of Culex pipiens in Moscow]. Resistance and irritability to permethrin, deltamethrin, bendiocarb, propoxur, fenitrothion, malathion, dieldrin and DDT (WHO standard papers) were determined in Culex pipiens collected in the basements of big houses in the centre of Moscow. Mosquitos were found to be moderately resistant to fenitrothion (87% mortality), DDT (83%) and propoxur (80%), and susceptible to the remaining insecticides. The irritability was low to dieldrin but moderate to permethrin, propoxur and DDT, and high to the rest. The irritability to bendiocarb seems to be really caused by the repellent action of citric acid which the WHO standard paper is impregnated with. It is recommended to use pyrethroids against mosquito larvae and pyrethroid brickets against adults.


[The point-scale assessment of the intensity of the possible contamination by helminth eggs of large reservoirs in the Volga basin]. Possibility for the contamination of man-made lakes by helminth eggs caused by superficial drain was estimated. The estimation allowed one to apply a differential approach to the organization of protection measures.


[The clinico-immunological characteristics of hymenolepiasis]. Clinical manifestations were observed only 16 out of 61 patients aged 15-32 years who had hymenolepiasis. Despite their degree, there was impaired dexylose absorption, lower serum lysozyme activity and higher serum complement activity, depressed immunological reactivity parameters (the count of T- and B-lymphocytes, their functional activity), decreased IgA titer and increased IgE titer in the sera in all the patients observed. Six months after the effective dehelminthization, varying immunodepression still remained in all the convalescents. There types of restoration of immunological reactivity were identified: torpid, reactive and highly reactive. The torpid type was significantly more frequently observed in patients with subclinical (asymptomatic) hymenolepiasis course than in patients with its clinical manifestation.


[Opisthorchiasis as a component in a mixed infection]. A survey of the same human contingents (children under 14 years and adults) in different zones of Ukraine revealed the opisthorchiasis foci of different intensity in the northeastern part of Polesye and in the forest-steppe zone. The affliction of adults ranged from 27.5 +/- 2.2% to 2.8 +/- 0.7%, that of children was from 14.5 +/- 2.3% to 0. In the foci of high and moderate tension, the trichocephaliasis prevalence was 10.2 +/- 0.7%, ascaridiasis 5.1 +/- 0.5%, amebiasis 2.4 +/- 0.7%, lambliasis 7.7 +/- 0.6%, and outside the foci these figures were lower (2.0 +/- 0.7%; 2.4 +/- 0.7%; 0.5 +/- 0.3%; 2.9 +/- 0.8%, respectively). In concurrent invasions and infections, the number of helminth eggs and protozoan cysts excreted by patients was significantly lower than in that in monoinvasion.


[The epidemiological characteristics of diphyllobothriasis caused by Diphyllobothrium klebanovskii in the Amur River basin]. The diphyllobothriasis incidence in the workers of the Amur basin steamship company during 1980-1989 was studied. This rate was shown to be more than 6 times than that of other population (68.7 and 10.4 case per 100,000 person, respectively). The role of the workers of the company in the circulation of the invasion and prophylactic measures in the region were discussed.


[The morphological changes in the organs of the lymphoid system in the experimental infection of mice with Trichinella spiralis]. The dynamics of morphological changes in central and peripheral organs of the lymphoid system of mice experimentally invaded with Trichinella spiralis was studied. The immune response of the host was shown to have two phases including two peaks and the suppression period. The activation of the lymphoid organs was observed in earlier intestinal and muscular phases, and the suppression was noted in migration phase of invasion.


[Sanitary parasitocenology. The subject, goals and tasks]. The necessity for developing a new parasitological discipline, such as sanitary parasitocenology, is evidenced. Training of specialists with a wide range of parasitological knowledge and goal-oriented complexation of the investigations of parasitologists of different profile are shown to be required. The necessity for elaborating the measures for disinfection of environmental objects is shown taking into account the degree of pathogenicity of each parasitocenosis.


[Group cryptosporidiosis morbidity in children]. The group morbidity with cryptosporidiosis (13 cases) was recorded in infants from a somatic hospital and a nursery school and also among unorganized groups. The factor of transmission was kefir prepared in the nursery milk kitchen. Cryptosporidian oocysts were not found in the personnel of the kitchen. It was supposed that the contamination of milk by oocysts occurred on milk farm. Single oocysts were found in milk sediments on the filter taken from a tank at a milk factory.


[The transformation of the saprotrophic mycelial form of the fungus Paecilomyces variotii into the tissue parasitic form and its morphological characteristics]. The fungus Paecilomyces variotii is known to develop as a saprotrophic mycelial form in the soil. When penetrating into the human organism or placing into a medium containing cultured cells it transforms into a parasitic flesh form. This form of the fungus was shown to undergo 3 morphological stages: endospore, juvenile (intermediate) form and mature sphaerula. The transformation of the mycelial form into parasitic one occurs in the biological media containing cells of the host, inside or outside the cell. The morphological structure of mycelium of P. variotii developed from the flesh parasitic form is different in aerobic and anaerobic conditions. In the former case, the spore production takes place by means of phialides, and in the latter case it occurs inside the mycelium.


[A case of pulmonary aspergillosis with the formation of mycetomas in a patient with acute leukemia]. The clinical and diagnostic features of fungal infection in hemoblastosis are discussed. It is shown that the adequate and early treatment allows the life-threatening complication to be managed.


[Cyclic changes in the population count of the taiga tick in the Stolby preserve]. A harmonic analysis was carried out of Ixodes persulcatus density dynamics over 33 years and the analysis of small mammal density and some climatic factors. It was found that the chronological changes of all the three processes contained cyclic components with the period 5.5 and 11; 3-4; 5.5 and 14-16 years, respectively. A long-term prognosis of I. persulcatus density was made based on harmonic synthesis.


[The clinico-parasitological examination of a focus of intestinal nematodiases in Ha-Shon-Bin Province in the People's Republic of Vietnam and an analysis of 5 medamine treatment schemes]. An intensive focus of intestinal nematodiases in a foothill province of Vietnam is described; the incidence of ascaridiasis there was found to be 81.8%, trichuriasis 78.1%, and ankylostomiasis 12.3%. Polyinvasions were detected in more than 80% of the examinees. Analysis of five schemes of medamin therapy, used in three provinces in 595 patients with ascaridiasis, 490 ones with trichuriasis, and 323 ones with ankylostomiasis has shown that the treatment efficacy was reducing with the invasion intensity augmentation. In ascariasis the 3- and 5-day therapeutic schemes were the most effective, their efficacies being 68.4 and 82.0%, respectively; in trichuriasis and ankylostomiasis a 3-day scheme was the best, its efficacies being 74.0 and 71.9%, respectively. Retrograde ascarid migration occurred in 1.2% of 595 ascaridiasis patients after medamin therapy.


[A clinico-epidemiological study of opisthorchiasis in the Altai Territory]. Eighty-eight patients with opisthorchiasis were treated with biltricide in an anthropurgic and natural focus of opisthorchiasis in the Altai Territory. A one-day course of drug therapy, in a total dose of 60 mg/kg, was administered. Forty-two patients developed side effects in the course of therapy. Complete elimination of the helminths was achieved in 83 (94.3 +/- 2.3%; p less than 0.05) patients in 6 months after therapy.


[The dynamics of the indices of opisthorchiasis invasion of the population of the Chulym River basin]. Based on the findings of a 20-year follow-up, the authors analyze the incidence of opisthorchiasis in one of the regions of the Krasnoyarsk Territory, the Chulym River region. They analyze the time course of the major parameters, i.e. incidence rate, absolute and relative increment of this value and the significance of a 1% increment as exemplified by this region. They emphasize that a complex of sanitary and hygienic measures should be implemented to control and prevent opisthorchiasis in this region.


[Bloodsucking mosquitoes on the irrigated lands of Kara-Kalpakia. 2. The annual cycle of Anopheles pulcherrimus]. The authors characterize the annual cycle of An. pulcherrimus population, distinguish the stages of this cycle that differ by the population composition and number and by the size of its area. The spatial structure of the population depends on the site of water bodies for wintering and the conditions at different territories. High numbers of mosquitoes were found in the southern part of the oasis at villages of rice-growing farmers. Mosquito population densities in the central parts of the oasis are much lower and are increased nearby sandy islets.


[The susceptibility of mosquitoes for Plasmodium gallinaceum in the joint use of biologically active substances]. Making use of a model pair Aedes aegypti--Plasmodium gallinaceum, the authors assess the susceptibility of mosquito female survivors to malaria agent after treatment of larvae with various bioactive substances. Eight binary combinations of 6 preparations have been tried: dimilin and uvemon, insect development regulators; fundosol and copper sulfate, fungicides; phytobacteriomicin (PBM), a larvicidal antibiotic; bactoculicide, a bacterial agent. Combinations of PBM with compounds differing by their mechanisms of action were found to inhibit the specific effect of PBM on the vector, PBM specific effect consisting in depression of mosquito susceptibility to P. gallinaceum. PBM combinations with some agents may alter other parameters of the vector potential: combinations of copper sulfate or uvemon with low concentrations of PBM potentiated the larvicidal effect, and PBM mixtures with fungicides reduces the activity of female attacks.


[The spread of Phlebotomus papatasi Scop., 1786 through the territory of Central Asia and southern Kazakhstan]. The data on distribution of the main vector of zoonotic cutaneous leishmaniasis (ZCL) Phlebotomus papatasi through Central Asia and southern Kazakhstan are presented. The highest indices of density of this species (100 and more specimen per stick trap) were observed only in the Tejen oasis, rather high ones (1-10, 10-100) in the river valleys and at the foothill, and the lowest one (0.01-0.1)--over the desert territory where ZCL was not practically found. Using these data 2 maps were prepared. The first map shows the pattern of Ph. papatasi geographical distribution with the use of a relative density index. This map can be useful for determining ZCL danger in areas where Ph. papatasi occurs. The second indicates sandfly distribution over Karshi steppe territory the where Ph. papatasi density depends on soil moisture. This map can serve as a model for forecasting Ph. papatasi density under anthropogenic influence.


[Ixodid ticks in the mountainous part of the Crimea]. About a hundred of patients with tick-borne encephalitis (TBE) were recorded over the latest decade in the Crimea, and 60 TBE virus strains were isolated from the ticks collected on the peninsula. The results of studies carried out in 1986-1990 helped define the borders of 4 local natural foci of TBE, study their acarifauna, detect the principal TBE vector--Ixodes ricinus (with a mean virophority of 0.6%), and distinguish two foci with a combination of TBE and Crimean-Congo hemorrhagic fever.


[The age-related structure of an Ixodes ricinus population studied by using a rapid anatomical method]. A rapid anatomic method for the assessment of the physiologic age of ticks and their virtual age was used in studies of the age structure of a natural population of I. ricinus in the Moscow region. The anatomic method was found quite fit for the purpose. The findings evidence that the age structure of I. ricinus (active imago) population is heterogeneous with variously directed seasonal fluctuations. In spring the structure is the youngest (up to 60% of imagoes are in the second age, 8 months) and in the fall the females are mainly old, just starting to get younger (up to 90% are in the third and fourth ages, that is, aged a year). The structure is liable to changes with seasons and years. Geographic differences in the age structures were revealed: in the fall the Moscow region population is generally older than that of the St. Petersburg region. The anatomic method widens the potentialities of studying the age structure of the populations of tick-borne encephalitis vectors.


[The participation of birds in the circulation of the tick-borne encephalitis virus in the Asian part of Russia. 1. Natural foci in the Far East]. Virologic examinations of 811 samples of 70 species and of 81 ova from layings of 11 bird species, carried out in natural foci of tick-borne encephalitis (TBE) in the southern Maritime [correction of Primorye] Territory, yielded negative results; serologic examinations revealed a low level of the immune stratum to TBE virus even in the birds feeding on the soil or on grass and shrubberies, that is, belonging to the first and second ecologic groups (0.8 +/- 0.4%). A difference has been demonstrated between the shares of TBE immune samples in the first and second+third (birds feeding on trees but sometimes on soil) +fourth (feeding on trees, in air, out of forests, on animals) ecological groups of birds, as well as between the first+second and third+fourth groups.


[The sensitivity of the tick Ornithodoros papillipes Bir. to Icon]. Laboratory trials have demonstrated a high and stable acaricidal activity of aikon towards O. papillipes ticks. The minimal dose (on filter paper) of aikon providing a 100% death of the ticks at all developmental phases, effective for at least 9-12 months, was 30 mg/m2. In exposure to this dose the ticks died within 1-7 days; if impregnated filter paper was stored for a long time, within 15-30 days. The lower the dose was, the slower the effect and lesser the total death rate of the ticks were.


[The characteristics of cryptosporidiosis prevalence in Nizhni Novgorod Province]. A total of 4070 patients with acute intestinal diseases were tested for cryptosporidiosis in 1989, 1806 of these without diarrhea (controls), 286 of them working at slaughter houses, milk-packing plants and dairy plants, 192 subjects with a history of contacts with cryptosporidiosis patients in the focus of the disease, and 7 animals. Cryptosporidiosis was responsible for 3.2% of acute intestinal conditions in children; cryptosporidia oocysts were not detected in adults or healthy subjects. The high risk group invasion has made up 2.7%. Two cases of the invasion were detected among subjects with a history of contacts with cryptosporidiosis patients, this making up 1.04%, none of them presenting with any clinical symptoms of the invasion.


[The microstructure of trematodes studied by electron microscopy]. The main tendencies in the studies into the ultrastructure of trematodes (including species of medical importance) using scanning and transmission electron microscopy are considered. Attention was paid to disproportions in the studies into the different developmental stages of trematodes: maritae are better studied than parthenogenetic and larval stages and especially eggs and miracidia. During the last years the number of studies using the complex of histochemical, radioisotope and electron microscopic methods is increasing, among them the investigations on the changes caused by modern anthelmintic agents in the tegument and viscera of trematodes. These are mainly the trematodes of Schistosomatidae, Echinostomatidae, Fasciolidae and Paragonimidae families that were studied by electron microscopy, and the studies on Opisthorchidae are very scarce.


[The efficacy of a new insecticide ethofenprox (Trebon) for controlling different types of insects]. The insecticidal action of the new compound ethofenprox (trebon) in the form of 10 and 30% flow concentrate against house flies, cockroaches, bed bugs, rat fleas, mosquito imagines and larvae of Aedes and Culex genera was studied in the laboratory and in the field. The effective doses and the methods of spraying were established. 10% flow trebon is allowed by the USSR Ministry of Health to be useful in medical disinfection.


[Clonorchiasis in the People's Republic of Vietnam. 2. The clinico-parasitological examination of a focus and a trial of prazinquantel treatment]. Examinations of 1599 residents of a polyinvasion focus at a seaside province Ha Nam Nin, Vietnam, have revealed clonorchiasis in approximately 13.9% of the examinees; in subjects aged over 30 this value was 29.3%. Factors conducive to a lower incidence of clonorchiasis were detected, among them a moderate intensity of the invasion: the mean arithmetic was 1419 +/- 306 eggs/g, the mean geometric 673 egg/g, as shown by the Kato-Kats' technique. Analysis of five therapeutic schemes used in clonorchiasis, making use of chloxilin, medamin or praziquantel, has demonstrated a low efficacy of all of them. Praziquantel therapy in a daily dose of 25 mg/kg for 2 days was found the most effective (52%), being conducive to a reduction of the invasion intensity by at least 90%. Such therapy was associated with a high incidence of side effects (91.2%), this ruling out a higher dosage.


Backscatter coefficient imaging using a clinical scanner. A clinical ultrasound scanner has been integrated with a digital data acquisition system to record echo signals for off-line processing of quantitative acoustic backscatter images. The method used to determine backscatter coefficients accounts for experimental factors related to the beam directivity function, the transmitting and receiving electronics, and the attenuation path of the beam. After characterization and calibration of the ultrasound scanner according to the data processing requirements, the quantitative backscatter coefficient for tissue-mimicking phantoms are within 14% of a value predicted by scattering theory. On five normal volunteers, preliminary in vivo liver images of the acoustic backscatter coefficient are obtained. Results from this study are compared to previously published in vitro results.


Image feature analysis and computer-aided diagnosis in digital radiography: automated detection of pneumothorax in chest images. In order to aid radiologists in the diagnosis of pneumothorax from chest radiographs, an automated method for detection of subtle pneumothorax is being developed. The computerized method is based on the detection of a fine curved-line pattern, which is a unique feature of radiographic findings of pneumothorax. Initially, regions of interest (ROIs) are determined in each upper lung area, where subtle pneumothoraces commonly appear. The pneumothorax pattern is enhanced by the selection of edge gradients within a limited range of orientations. Rib edges included in this edge-enhanced image are removed, based on the locations of posterior ribs that are determined separately. A subtle curved line due to pneumothorax is then detected by means of the Hough transform. The detected pneumothorax pattern is marked on the chest image displayed on a CRT monitor. With the present computer method applied to 50 chest images (28 normals and 22 abnormals with pneumothorax), we were able to detect 77% of pneumothoraces, with 0.44 false-positives per image.


Highly stable solid-state x-ray detector array. A detailed analysis of the effects of temperature changes, over time and between array elements, on the generation of circular artifacts in images produced by x-ray computed tomography was reported. We give formulas for calculating--according to the x-ray energy, detector sensitivity, and observed image quality (contrast and spatial resolution)--the maximum offset temperature coefficient and maximum gain temperature coefficient that will allow circular-artifact-free imaging. A temperature-controlled and insulated solid-state x-ray detector array, consisting of Gd2O2S:Pr,Ce,F ceramic scintillators coupled to crystal Si pin-photodiodes and designed to meet the requirements for these coefficients, produced high-resolution artifacts-free CT images of a phantom head.


Contrast-detail curves for liver CT.

Contrast-detail curves for liver CT. Contrast-detail curves were constructed for liver computed tomographic (CT) images using an objective method. Stimuli were created by superimposing disks at specified locations on sets of 92 normal liver CT images. Bright and dark disks of 9 sizes and 36 possible image contrasts were used. Sets of 92 stimuli were rendered on film at five window widths (64, 128, 256, 512, and 1024 HU). The contrast-detail (CD) curve flattened substantially for disks larger than 7-mm diameter, and its slope (on a log-log plot) was less than predicted from signal-detection theory. Manipulation of display window manipulation had little impact on this disks' visibility. The results indicate that human observers have difficulty visualizing large, low-contrast details on liver CT scans, and suggest that narrowing the display window will have little effect on this limitation.


Application of the EM algorithm to radiographic images. The expectation maximization (EM) algorithm has received considerable attention in the area of positron emitted tomography (PET) as a restoration and reconstruction technique. In this paper, the restoration capabilities of the EM algorithm when applied to radiographic images is investigated. This application does not involve reconstruction. The performance of the EM algorithm is quantitatively evaluated using a "perceived" signal-to-noise ratio (SNR) as the image quality metric. This perceived SNR is based on statistical decision theory and includes both the observer's visual response function and a noise component internal to the eye-brain system. For a variety of processing parameters, the relative SNR (ratio of the processed SNR to the original SNR) is calculated and used as a metric to compare quantitatively the effects of the EM algorithm with two other image enhancement techniques: global contrast enhancement (windowing) and unsharp mask filtering. The results suggest that the EM algorithm's performance is superior when compared to unsharp mask filtering and global contrast enhancement for radiographic images which contain objects smaller than 4 mm.


Region of interest fluoroscopy.

Region of interest fluoroscopy. In some medical imaging applications, it is necessary to visualize only the center of the field of view with optimal quality. For example, often in interventional radiographic procedures only the region directly adjacent to the catheter tip must be well seen. A new imaging approach which reduces the number of photons exposing the patient outside a region of interest (ROI), while allowing the photon fluence to be maintained or increased in the ROI, may make more optimal use of the total integral radiation dose to the patient as well as enable increased contrast and reduced artifacts in the ROI. A demonstration is given with an angiographic phantom, for an ROI which is less than 10% of the total field of view and where the periphery receives 6% of the ROI exposure. Contrast is improved about 30% in the ROI, and yet the images are adequate in the periphery for visualizing high contrast reference features while there is a reduction in total integral patient dose. Details of the technique are discussed along with requirements for clinical implementation.


Some noise properties of 2DFT MR images from asymmetrically sampled data. This report describes noise statistics in 2DFT MR images, expanding the earlier work of Henkelman and others to include variably asymmetric sampling and conjugate synthesis reconstruction. The effects of low-order polynomial and Fourier phase correction used with conjugate synthesis are also explicitly considered. This analysis shows that complex images obtained by conjugate synthesis have an elliptical noise distribution, with the smaller axis corresponding to the imaginary image channel. Derivations and simulations predict a ratio of mean to standard deviation in the background of magnitude images varying from the known value of square root of pi/(4 - pi) (approximately 1.91) for full symmetry to square root of 2/(pi - 2) (approximately 1.32) at fully asymmetric or half-echo sampling; these predictions are validated over a range of asymmetry by experimental measurements. These results are important for predicting and interpreting image noise when using asymmetric sampling.


Mammography screen-film selection: individual facility testing technique. Variations in tube output, film processing, and radiologist's preferences affect the screen-film combination that is appropriate for any particular mammographic facility. A technique to test a variety of screen-film combinations for screening mammography is described. Films are selected for testing because of their densitometric characteristics. Dose and clinical reliability are established with phantoms before the screen-film combinations are used to image consecutive patients having bilateral examinations. The mammograms selected for evaluation are those with similar optical density ranges, and which also may be compared to available previous mammograms or which have unusual mammographic findings. All radiologists reading mammograms at a facility independently score the selected cases. Scores of "unacceptable," "acceptable," or "outstanding" are assigned to four basic imaging characteristics: sharpness, contrast, visibility of skin line, and noise. Interobserver variations by this method require normalization, unlike ROC analysis which is not applicable for this data because of the absence of proved pathologic diagnoses. The testing of 5 films and two screens using 42 patient examinations required 2 h of time from each radiologist. It took 7 h of the physicist's time to pretest the 5 films, select the 42 acceptable examinations for testing by the radiologists, and summarize the data.


Comparisons of sectioned micro-TLD dose measurements with predicted dose from 131I-labeled antibody. The dose distribution from radioimmunotherapy is very heterogeneous because of variability in antigen expression, antibody penetration, and tumor architecture. Many models of dose distribution have been constructed but it has been very difficult to confirm these predictions with actual measured doses. The purpose of this study was to determine what degree of resolution could be obtained using mini-thermoluminescent dosimeter(s) (TLD) in a micrometastasis model. TLDs were inserted into 1-mm-diam multicell tumor spheroids that had been treated with 131I-labeled antibody. The spheroids were then sectioned at 30-microns intervals and the TLD sections (measuring 0.14 x 0.1 x 0.03 mm) were removed and read. Calibration of the TLDs was done with whole TLDs using external beam radiation and an 131I-containing gel, and with TLD sections using external beam radiation. Predicted doses were determined by measuring the activity in individual spheroids and the time the TLDs were in the spheroids and incorporating these numbers into a model that assumed either surface binding of 131I or some degree of penetration. There was a correlation between the measured TLD dose and the predicted absorbed dose when comparing the low- to high-dose regions. However, there was considerable variation within any particular dose range, probably due to heterogeneity in TLD grain size.(ABSTRACT TRUNCATED AT 250 WORDS)


A technical analysis of an intraoperative radiation detection probe. A technical evaluation was made of a commercial intraoperative radiation probe. This device utilizes a CsI (T1) scintillation detector and light pipe arrangement to count gamma radiation in vivo. After determining the optimal window and threshold setting, additional evaluations included linearity, distance response function, detector dead time, counter reproducibility, detector sensitivity, angular resolution, and energy resolution. Detector dead time (21.2 microseconds) was found to be characteristic of a nonparalysable system. Activity response for each radionuclide was linear (R = 0.99) both with and without collimation. Energy resolution, 25% at 210 keV, was not sufficient to separate the two photons (172 and 247 keV) emitted by 111In. Detector sensitivity was 1136 and 626 counts per s per microcurie of 111In and 99mTc, respectively. The mean effective distance from the face of the uncollimated probe to the crystal was determined to be 2.03 cm in air.


The advantages of absorbed-dose calibration factors. A formalism for clinical external beam dosimetry based on use of ion chamber absorbed-dose calibration factors is outlined in the context and notation of the AAPM TG-21 protocol. It is shown that basing clinical dosimetry on absorbed-dose calibration factors ND leads to considerable simplification and reduced uncertainty in dose measurement. In keeping with a protocol which is used in Germany, a quantity kQ is defined which relates an absorbed-dose calibration factor in a beam of quality Q0 to that in a beam of quality Q. For 38 cylindrical ion chambers, two sets of values are presented for ND/NX and Ngas/ND and for kQ for photon beams with beam quality specified by the TPR20(10) ratio. One set is based on TG-21's protocol to allow the new formalism to be used while maintaining equivalence to the TG-21 protocol. To demonstrate the magnitude of the overall error in the TG-21 protocol, the other set uses corrected versions of the TG-21 equations and the more consistent physical data of the IAEA Code of Practice. Comparisons are made to procedures based on air-kerma or exposure calibration factors and it is shown that accuracy and simplicity are gained by avoiding the determination of Ngas from NX. It is also shown that the kQ approach simplifies the use of plastic phantoms in photon beams since kQ values change by less than 0.6% compared to those in water although an overall correction factor of 0.973 is needed to go from absorbed dose in water calibration factors to those in PMMA or polystyrene. Values of kQ calculated using the IAEA Code of Practice are presented but are shown to be anomalous because of the way the effective point of measurement changes for 60Co beams. In photon beams the major difference between the IAEA Code of Practice and the corrected AAPM TG-21 protocol is shown to be the Prepl correction factor. Calculated kQ curves and three parameter equations for them are presented for each wall material and are shown to represent accurately the kQ curve for all ion chambers in this study with a wall of that specified material and a thickness less than 0.25 g/cm2. Values of kQ can be measured using the primary standards for absorbed dose in photon beams.


Analysis of contributing factors to the occurrence of off-focus radiation (OFR). Off-focus radiation (OFR) has previously been described by many investigators [R. Thoraeus, Acta Radiologica 18, 753 (1937); L. Mallet and R. Maurin, Radiology 48, 628-632 (1947); J. F. Timmer, Medicamundi 19(2), 52-54 (1974); G. U. Rao, Appl. Radiol. 3(3), 45-49 (1974); R. Birch, Br. J. Radiol. 49, 951-955 (1976); W. W. Roeck, AAPM Symposium, 217-247 (1991)]. Off-focus radiation is frequently manifested on radiographs by the appearance of faint images of anatomical structures outside the collimated field of interest, i.e., soft tissues, ear lobes and hair, which we will refer to as "penumbral images." The observable small detail resolution within these penumbral images led to the assumption that minute sources of increased radiation intensity (secondary microfocal spots) must be present outside the area of the primary focal spot. The existence of these multiple secondary microfocal spots has been established and their locations within the area of the anode surface from which the general OFR originates was identified. The number, size, and distribution of the secondary focal spots vary over time and their magnitudes vary widely. The source of the well-focused electron beams creating the spots is attributed to the cold cathode emission principle.


Performance characteristics of transmission imaging using a uniform sheet source with parallel-hole collimation. Transmission imaging is receiving increasing attention in SPECT due to the need to compensate for nonuniform attenuation in cardiac-chest SPECT. The quality of a transmission image has an important effect on the measured attenuation distribution. To improve image quality, knowledge of the performance characteristics of a transmission imaging system is essential. The characteristics, spatial resolution, detection efficiency, photon flux, and exposure to the object, of a transmission imaging system consisting of a gamma camera and a uniform sheet source have been studied. The results demonstrate that spatial resolution of a transmission imaging system can be improved by use of a high-resolution source collimator at the price of a moderate decrease in detection efficiency, in comparison to the uncollimated case. Also, the source collimator significantly reduces the photon flux and exposure to the object. This investigation suggests that a high-resolution collimator be used with an intense sheet source to improve spatial resolution and reduce statistical noise with low exposure to the patient. This research further suggests that the amount of source activity is determined by the requirement of image quality, detection geometry, and allowed absorbed dose to the patient.


Clinical dosimetry for implementation of a multileaf collimator. In order to initiate the use of a multileaf collimator (MLC) in the clinic, a set of technical procedures needs to be available sufficient to create MLC leaf settings and to deliver an accurate dose of radiation through the MLC-shaped field. Dosimetry data for clinical use of the MLC were measured. Dosimetric characteristics included central axis percent depth dose, output factors, and penumbra. In this paper, it has been concluded that a dose control monitor unit calculation procedure that has been applied to the use of conventional secondary field-shaping blocks can be applied to the multileaf collimator dosimetry. The multileaf collimator penumbra (20% to 80%) is only slightly wider (1-3 mm) than the penumbra of the conventional collimator jaws. Beam's-eye-view comparisons made between the isodose curves in fields shaped by conventional Cerrobend blocks and isodose curves in fields shaped by the multileaf collimator demonstrated that the 50% isodose line at 10-cm depth exhibited the discrete steps of the multileaf collimator leaves, but that the 90% and 10% isodose curves of the multileaf were close to those shaped by Cerrobend blocks.


Missing tissue compensators: evaluation and optimization of a commercial system. A commercial system for producing retracted compensators has been adapted to suit local needs, and is evaluated here. It comprises a magnetic field surface digitizer and computer-driven milling machine. Improvements in dose distributions, resulting in standard deviations of the mean dose between 2% and 3%, have been achieved for treatment fields in wax phantoms simulating the head and neck regions. Optimization of compensator shape to allow for changes in the amount of scattered radiation has resulted in a further improvement in dose uniformity, particularly near the field borders; for these compensators the standard deviation was as low as 1.6%. The system using the basic algorithm has been in clinical use since July.


Gadolinium neutron capture therapy for brain tumors: a computer study. A Monte Carlo computer study of the total dose distribution from neutrons and prompt gamma emissions (but excluding the contribution from conversion and Auger electrons) for gadolinium neutron capture therapy of brain tumors has been carried out in order to test the theoretic feasibility of this modality using commercially available magnetic resonance contrast media. The three-dimensional dose distribution calculations were performed in a spherical head phantom with a spherical tumor at the center. Potentially achievable gadolinium concentrations of 150 micrograms/g of tissue in tumor and 3 micrograms/g in normal tissue were assumed with enrichment to 79.9% gadolinium-157, as supplied by Oak Ridge National Laboratory. Irradiation was assumed to be with a 2-keV monoenergetic cylindrical epithermal neutron beam having a radius of 4 cm. The three-dimensional thermal neutron fluence resulting from the 2-keV beam propagation through the tissue was modeled. For a single neutron beam, the maximum dose is delivered within the tumor but the dose is very inhomogeneous across the tumor volume due to rapid decrease of thermal neutron fluence with depth. Two parallel opposed neutron beams deliver to the interface of normal and malignant tissue 70%-80% of the maximum dose received at the center of the tumor. To deliver an average tumor dose of 500 cGy in 10 min would require a 2-keV source neutrons number of 8.0 x 10(11) per s within the geometry of the beam.


Electron dose calculation using multiple-scattering theory: evaluation of a new model for inhomogeneities. In this article, the fifth in a series on the calculation of electron dose using multiple-scattering theory, the predictions of a new model for dealing with localized inhomogeneities will be examined (Med. Phys. 18, 123-132, 1991). That model is in the form of a perturbation series, and for a thick half-slab configuration explicit formulas are worked out for the dose directly deposited by the primary electrons, for three reasonable cutoffs of the series. The predictions of this model with EGS4 Monte Carlo calculations for the half-slab configuration are compared, and they are found to be quite accurate in the region under the edge of the half-slab. On the other hand, the "Hogstrom algorithm," which is currently the most advanced method in routine clinical use, is found to give poor accuracy for this configuration.


Skin dose measurements for head and neck radiotherapy. The use of immobilization plastic masks in head and neck radiotherapy can partially eliminate skin benefits derived from the utilization of megavoltage photon beams. Filters and blocks between the patient and the accelerator can further increase the skin dose value. In this study, the increase in surface dose due to 2 and 3.2 mm of plastic material utilized for patient immobilization was measured. Then, the effect of blocking trays, wedges, and blocks on skin dose in typical conditions for head and neck irradiation was evaluated. The measurements were obtained with a NE2534 chamber (Markus type) on a perspex phantom for 6 MeV x-rays from an accelerator.


Neutron fluence and kerma spectra of a p(66)/Be(40) clinical source. High-resolution neutron fluence spectra have been measured in the National Accelerator Centre's p(66)/Be(40) neutron therapy beam by the pulsed-beam time-of-flight method. ICRU muscle kerma spectra have been derived from the fluence spectra. Spectral changes resulting from different irradiation conditions have been quantified in terms of the average neutron energy and the fractional low-energy (< 16 MeV) contribution. The changes observed with different thicknesses of polyethylene filtration are consistent with changes in quality parameters determined in biological and microdosimetric experiments. The dosimetry parameters (KtissueA150) N and (Wgas) N calculated for the measured spectra agree with the values recommended in the neutron dosimetry protocol. The shapes of the present fluence spectra differ from previous measurements of p(> 40)/Be spectra. In particular, they differ significantly from the spectrum measured by recoil techniques in an identical neutron therapy unit at the Clatterbridge Hospital, UK. The reasons for the difference are not known.


Treatment planning for asymmetric jaws on a commercial TP system. In this work, the accuracy of the asymmetric jaws planning feature in a commercial treatment planning (TP) system is assessed. In the latest version of this software, the off-axis beam quality variation is handled by a function g(d,r), which is derived from measured horizontal beam profiles at four different depths. The calculated and measured isodoses for a 6-MV linear accelerator with asymmetric jaws agree to +/- 0.5% along the central axis and to within 2 mm at the beam edge. Formulas for treatment time calculations using the output data reported by the computer program are described, as well as formulas for manual calculations based on pregenerated data tables. Doses calculated based on these formulas are compared to measurement and the accuracy is +/- 1% and +/- 2% for the computer and manual calculations, respectively. It is concluded that this version of the treatment planning system as well as the treatment time calculation formulas can be used adequately for asymmetric jaw computerized and manual treatment planning.


Thermal and scatter effects on the radiation sensitivity of well chambers used for high dose rate Ir-192 calibrations. High dose rate (HDR) iridium sources must be calibrated regularly because of the short half-life of Ir-192. High dose rate sources can now be calibrated using a new well-type chamber that allows easy, reproducible source calibrations. The chamber includes a styrofoam insulator that surrounds the source in the well. A study of the radiation sensitivity of the well chamber exposed to an HDR Ir-192 source at two different activities (300 and 230 GBq) revealed that the sensitivity of the chamber varies by as much as 1.1% as the chamber is moved toward a scattering surface. Second, with the styrofoam insulator removed, the air temperature within the ion collecting volume increased during exposure, causing a gradual decrease in chamber sensitivity of 0.15% in 30 min. This temperature increase was caused by heat transfer from radiation emitted by the Ir-192 source, and diminished as the source decayed. However, with the styrofoam insulator around the central aluminum tube in the well, the source cannot heat the collecting volume and thus thermal equilibrium between the ion collecting volume and its environment is maintained throughout an exposure. The radiation sensitivity of the commercial well chamber was found to be constant for exposure times of 30 min.


Differential effects of metal ions on type A and type B monoamine oxidase activities in rat brain and liver mitochondria. To investigate the hypothesis that neurotoxic metals can exert their toxicity through the direct inhibition of monoamine oxidases (MAOs), the effects of several neurotoxic metal ions on type A (MAO-A) and type B (MAO-B) monoamine oxidase activities in rat forebrain nonsynaptic mitochondria and rat liver mitochondria were studied. At pathophysiological levels (10-100 microM), Cu2+ and Cd2+ are good inhibitors of brain mitochondrial MAO-A and, to a lesser extent, liver mitochondrial MAO-A. The inhibition of MAO-B activities in brain and liver mitochondria by Cu2+ and Cd2+ is only detected at the higher end of the concentration range (i.e., 50-100 microM). At the pathophysiological level of 0.5 mM, Al3+ only inhibits brain mitochondrial MAO-A but at the higher level of 2.5 mM, it inhibits both forms of MAO in brain as well as liver mitochondria. Even at toxic levels (e.g., 5 mM), neither Mn2+ nor Li+ inhibits the activities of MAO-A and MAO-B in brain and liver mitochondria. Our results are consistent with the hypothesis that some neurotoxic metals can exert their toxicity through the direct inhibition of the isoforms of MAO. Our data also suggest that the selective inhibition of brain MAO-A by Cu2+ and Cd2+ may assume pathophysiological importance in the neurotoxicity of copper and cadmium.


Evaluation of the buildup effect of an 192Ir high dose-rate brachytherapy source. The buildup effect of the 192Ir radioactive source employed as a gamma emitter of the Selectron high dose-rate (HDR) afterloader was evaluated by studying the ratio of exposure in water to exposure in air as a function of distance. In 1968, Meisberger et al. [Radiology 90, 953-957 (1968)] calculated a third-order polynomial fit to a selected average between measured and calculated values. The objective of this investigation, however, is to evaluate the factor for the 192Ir source configuration used in the HDR system, which was different from the source design used by Meisberger et al. This paper presents the measured ratio using an ionization chamber and the calculated ratio using a Monte Carlo simulation code. The experimental and theoretical results show only minor disagreement with the data of Meisberger et al. However, the results show significant disagreement when they are compared to the model developed by van Kleffens and Star [Int. J. Radiat. Oncol. Biol. Phys. 5 557-563 (1979)], which may indicate the need to reevaluate the algorithm presently employed in HDR treatment planning system. The comparison with other published data will be discussed.


Dose distributions produced by shielded applicators using 241Am for intracavitary irradiation of tumors in the vagina. Dosimetric characteristics of shielded vaginal applicators containing encapsulated 241Am sources are investigated in this work. Encapsulated 241Am sources emit primarily 60-keV photons which are more effectively shielded by thin layers of high atomic number materials than the 662-keV photons from 137Cs sources. With 241Am, it is possible to achieve almost unidirectional irradiation of localized vaginal tumors. The drastic decrease in irradiation volume on the contralateral side (uninvolved with tumor) is observed to decrease dose by up to 20%, even in the forward direction (unshielded side toward the tumor) of the applicator. A possible explanation for the observed effects of shields in both the forward and backward directions is the reduction of scattered photon fluence due to absorption of photons in the lead shield via photoelectric effect. Current theoretical models do not include this perturbation effect caused by shields on brachytherapy applicators.


Two-radiograph reconstruction using six geometrical solution sets and least-squares method. When two radiographic projections are available for reconstruction, it was found that six different combinations of equations could be used to obtain the geometrical solutions for the position of any point. No errors in the image coordinates read from the radiographs resulted in identical solutions for the six equations. Inaccuracies or errors present in the image coordinates generated differences among the six solutions. In this case, a least-squares method could be used to determine the optimum position. The utility of such a least-squares optimizing approach is presented in the context of a clinical example.


Thermocouples--the Arizona experience with in-house manufactured probes. The performance of several different types of multisensor thermocouple probes have been tested to determine the feasibility of each type for use in the hyperthermia clinic. All of the probes tested were manufactured in-house, and a detailed description of the construction process will be presented. The overall performance of the probes in terms of robustness, calibration, conduction errors, and response time will be described. In particular, this study describes our experience with in-house manufactured thermocouples over the past several years. The results indicate that when strict quality assurance guidelines are followed, in-house manufactured thermocouples perform satisfactorily--thereby providing an alternative to purchasing probes and measurement systems from commercial vendors if the proper resources are available.