Preconditioning: a new technique for improved muscle flap survival. Musculocutaneous regional and distal flaps have become an important tool available to the head and neck surgeon. Vascularized autogenous muscle transplants allow single-stage reconstruction of complex defects. Ischemic muscle necrosis is a well-recognized complication with serious potential morbidity. It has been shown that myocardial muscle is protected from ischemic damage by brief periods of coronary artery occlusion and reperfusion subsequent to prolonged ischemia. This is called preconditioning. To our knowledge, this technique has never been extrapolated to skeletal muscle. This article presents a discussion of preconditioning and the potential benefits of this new technique as a means to enhance skeletal muscle survival to sustained normothermic global ischemia. Theories behind ischemic muscle injury are presented. A review of the development of preconditioning in myocardial muscle is discussed. Experimental models used to investigate this phenomenon are also presented. In addition, results of our laboratory investigations using the latissimus dorsi porcine model are discussed. Preconditioning is a new, nonpharmacologic means to improve muscle flap survival. This simple technique may have great clinical application in reducing ischemic muscle necrosis in regional and distal muscle transplantation.


Acoustic characteristics of post-thyroplasty patients. This study investigated changes in voice quality after thyroplasty type I in eight adults with unilateral vocal fold paralysis. A silicone rubber implant was inserted through a window in the thyroid ala and placed between the inner and outer perichondrium to externally medialize the abducted vocal fold. Measures of fundamental frequency (vocal pitch), pitch range, maximum phonation time, s/z ratio, pitch perturbation (vocal jitter), and amplitude perturbation (vocal shimmer) were made 1 to 2 weeks preoperatively and 1 month postoperatively. Postoperative voice quality was characterized by an improved pitch range, phonation time, s/z ratio, and pitch and amplitude perturbation. No change was noted in fundamental frequency. Changes in postoperative voice quality were unrelated to the subjects' preoperative age, sex, etiology, and duration of the paralysis.


Complications of lumbar spinal fluid drainage. Cerebrospinal fluid fistula is an unfortunate, yet well-recognized, complication of basilar skull fracture, skull base surgery, and neurotologic procedures. Treatment commonly involves the use of continuous lumbar drainage. A retrospective chart review of 32 consecutive patients who required placement of lumbar drain by the otorhinolaryngology and neurosurgical services from March 1988 through July 1991 was undertaken to assess possible complications. The complications found were readily separated into minor and major categories on the basis of the possibility of permanent morbidity or mortality. Minor complications, including subjective complaints of headache, nausea, vomiting, etc., were noted in 59% of patients. Major complications were observed in four of 32 patients (12.5%), including unilateral occlusion of the posterior cerebral artery and unilateral true vocal cord paralysis. Alleviation of all complications was achieved by cessation of lumbar drainage. These cases are presented with discussion of pathogenesis. These findings demonstrate the possibility of potentially serious complications that mandate close monitoring of patients who require continuous lumbar drainage.


Head-upright tilt-table testing: a useful tool in the evaluation and management of recurrent vertigo of unknown origin associated with near-syncope or syncope. Recurrent idiopathic vertigo associated with near-syncope and syncope is a common perplexing problem, some cases of which are considered autonomically mediated (vasovagal). Upright-tilt-table testing has emerged as a potential method to test for vasovagal episodes. This study evaluated the use of this technique in the evaluation and management of patients with recurrent idiopathic vertigo associated with near-syncope or syncope. Twenty-one patients with recurrent unexplained vertigo and syncope/near-syncope and 11 control subjects were evaluated by use of an upright-tilt-table test for 30 minutes, with or without a graded isoproterenol infusion (1 to 4 micrograms/min given intravenously), in an attempt to provoke hypotension, bradycardia, or both, which reproduced the patient's symptoms. The patients included 10 men and 11 women (mean age, 51 +/- 16 years). Eleven controls with no history of vertigo were also studied. Transcranial Doppler sonography was used to assess cerebral arteriolar blood flow during tilt. All tilt-positive patients were placed on therapy with either beta-blockers, disopyramide, or transdermal scopolamine, the effectiveness of which was determined with another tilt-table study. Symptoms occurred in seven patients (33%) during the baseline tilt and in eight patients (38%) during isoproterenol infusion (total positives, 71%). Transcranial Doppler sonography demonstrated a 225% +/- 192% increase in pulsatility index and a 70% +/- 29% increase in resistance index (indicative of cerebral arteriolar vasoconstriction) at the time of vertigo. No control subject experienced syncope during this test. Each tilt-positive patient eventually became tilt-negative with therapy, and over a mean follow-up period of 26 months, no further episodes have occurred.(ABSTRACT TRUNCATED AT 250 WORDS)


Risk factors of cancer of the larynx: results of the Heidelberg case-control study. Squamous cell carcinoma of the larynx is a multifactorial disease. It is firmly linked to several environmental risk factors. In the meanwhile, a considerable amount of epidemiologic evidence has been built up to implicate chronic consumption of alcohol and tobacco, occupation, diet, and social status in the etiology of the laryngeal cancer. Herein is a report from the first case-control study on the role of these risk factors conducted in a German population of patients with laryngeal cancer.


Comparison of electroglottographic and acoustic analysis of pitch perturbation. Pitch perturbation is a measure of the cycle-to-cycle variation in vocal fold vibration. Perturbation can be assessed by means of electroglottographic or acoustic signals. The purpose of this study was to determine if these two analysis techniques are equivalent measures. The Laryngograph, an electroglottograph, and the Visi-Pitch, an acoustic analyzer, were used to measure pitch perturbation in 80 dysphonic subjects. Both instruments use Koike's formula to calculate relative average perturbation. While intra-subject variability appeared erratic, statistical analysis of intersubject data indicated that the two instruments provided an equivalent measure of pitch perturbation.


Nasal reconstruction using split calvarial grafts. The reconstruction of nasal deformities after trauma or surgical procedures presents an arduous task for the reconstructive surgeon. The anatomic alteration of supporting cartilage and nasal bones, as well as scar formation, compound the difficult nature of this type of reconstruction. In the past, multiple autogenous and alloplastic implants have been used in nasal reconstruction. Autogenous implants include auricular and septal cartilage as well as rib and iliac crest bone grafts. Alloplastic materials include acrylic, supramid mesh, Gortex, and silicone rubber. Autogenous grafts have been shown to provide excellent long-term reliable results in nasal reconstruction. In our study, autogenous split calvarial bone grafts were used in the nasal reconstruction of 17 patients. Among the corrective procedures were dorsal augmentation for saddle-nose deformities, insertion of columella struts for nasal tip ptosis, and insertion of nasal battens for nasal valve collapse. Patient followup has been from 1 to 5 years, with no significant resorption noted during that time. Complications were limited to one seroma at the donor site before wound drains were routinely used. No major complications, including hematoma formation, CSF leak, or infection, have been observed.


Vestibular rehabilitation reduces functional disability. Vertigo caused by vestibular disorder may be successfully treated with a physical therapy program of graded exercises to habituate the patient to the vertiginous stimulus and to increase the range of motion through which the patient can tolerate moving. Performance on daily self-care tasks is an important indicator of the patient's tolerance for head movement and the success of treatment. In this study, self-care skill in subjects with labyrinthine and brainstem lesions before and after receiving vestibular rehabilitation was examined. Subjects improved significantly after physical therapy, demonstrating greater independence in their abilities to care for themselves. These data provide further support for the value of vestibular rehabilitation procedures.


Tympanosclerosis of the stapes: hearing results for various surgical treatments. When tympanosclerosis involves the tympanic membrane or the lateral ossicles, treatment is usually straightforward and uncomplicated. When the stapes is involved, therapy is more controversial and may be more difficult. We report our results in 154 patients who underwent different surgical procedures for tympanosclerosis of the stapes. Followup was up to 10 years. Pure-tone average threshold was significantly improved (p < 0.05) in patients who underwent mobilization procedures or stapedectomy for definitive treatment. The air-bone gap was less than 20 dB at 6 months postoperative in 72% of patients and less than 30 dB in 90%. At 6 months, 2 years, and 5 years there were no statistically significant differences in hearing results between stapedectomy and mobilization patients, some of whom were followed for up to 10 years. No patient had a profound hearing loss after surgery. Surgical treatment for tympanosclerosis of the stapes is a safe procedure, with hearing results similar to those of surgery for other chronic ear diseases involving the ossicular chain.


A multisensor solid-state pressure manometer to identify the level of collapse in obstructive sleep apnea. The cause of failure after uvulopalatopharyngoplasty (UPPP) in idiopathic obstructive sleep apnea (OSA) is poorly understood, but has been speculated to be due, in part, to persistent collapse in the lower oropharynx. In order to determine the specific level of upper airway obstruction during sleep, a multisensor pressure catheter has been developed with five solid-state ultraminiature sensors. Four sensors in the pharynx simultaneously measure multiple pressure levels, with no need to move the catheter during sleep. One distal esophageal port measures the respiratory effort. To evaluate the use of this catheter, manometry in twelve patients was reviewed and compared the use of this catheter, manometry in twelve patients was reviewed and compared to simultaneous videoendoscopy. The initial site of obstruction was the palate in nine patients (75%) and the tongue base in three (25%). Three patients with initial obstruction at the palate manometrically demonstrated distal obstruction on subsequent occluded breaths. Furthermore, simultaneous videoendoscopy in four patients with a palatal level of obstruction also identified marked near-total visual collapse without obstruction of the lower oropharynx that was not identified by pharyngeal manometry. The endoscopy revealed that at the initial site of obstruction, collapse appeared to have occurred passively during expiration and not on inspiration. Inferior to the site of manometric obstruction, collapse occurred during inspiration associated with increased negative inspiratory pressures. These results demonstrate that a multisensor pressure catheter can objectively identify the level of obstruction during sleep.(ABSTRACT TRUNCATED AT 250 WORDS)


Bilateral thyroarytenoid denervation: a new treatment for laryngeal hyperadduction disorders studied in the canine. Adductor spasmodic dysphonia is a vocal disorder of uncertain etiology with no satisfactory long-term treatment. Recently, injection of botulinum toxin (Botax) into the thyroarytenoid (TA) muscle has been used as an effective temporary treatment. A surgical counterpart to bilateral TA Botox injection is described in this article. Bilateral thyroarytenoid denervation was performed through a window in the thyroid cartilage in seven canines, including four that were studied 3 months after the procedure. No serious complications occurred in the animals, each maintaining full vocal fold abduction and adduction. In all cases, anticipated physiologic changes in laryngeal function were observed, including the inability to generate high subglottic pressures during high levels of laryngeal nerve (RLN) stimulation. In two of the surviving animals, the ansa cervicalis was used to reinnervate the TA muscle, thereby preventing the possibility of reinnervation from the proximal RLN stump while limiting TA atrophy and fibrosis. Bilateral TA denervation represents a hopeful new long-term approach to spasmodic dysphonia treatment.


Repair of chronic tympanic membrane perforations using epidermal growth factor. Perforation of the tympanic membrane (TM) is a frequent cause of conductive hearing loss. Persistent TM perforations often require surgical repair with an autologous tissue graft to restore hearing and prevent recurrent infection. While highly efficacious, this method of closure requires a relatively complex and expensive microsurgical procedure. We have recently developed a chronic TM perforation model in the chinchilla for use in the exploration of novel methods of TM repair.


An evaluation of laryngeal muscle activation in patients with voice tremor. Eight patients with voice tremor were studied to characterize laryngeal muscle involvement. Electromyographic (EMG) recordings were made from intrinsic laryngeal muscles, simultaneously with some extrinsic laryngeal muscles, respiratory movement, and voice recordings during respiration, whisper, and phonation. Spectral measures were used to determine the tremor frequency and the prominence of spectral peaks in the EMG, respiratory and acoustic signals, while correlation coefficients were computed between pairs of tremulous EMG signals to measure the synchrony of tremor between muscles. The intrinsic laryngeal muscles were tremulous during respiration and speech, with the thyroarytenoid most often involved. Tremor was also detected in some of the extrinsic muscle recordings and the percentage of muscles with tremor was higher during phonation than during whisper or respiration. Time delays were found between tremor oscillations in laryngeal muscles. Because the thyroarytenoid was affected in all the patients studied, botulinum toxin injections may be beneficial in treatment of this voice disorder.


Incidence of otitis media in vitamin A-deficient guinea pigs. After observing an association between vitamin A deficiency and otitis media among children in Micronesia, we sought to develop an animal model for vitamin A-deficiency-induced otitis media. Thirty juvenile guinea pigs were screened for absence for otitis and then divided into two groups. The experimental group was placed on a vitamin A-free diet, whereas control animals were fed a standard formula. The animals were followed by means of otologic examination and serum retinol determinations. When experimental animals demonstrated vitamin A deficiency, they were killed along with one control and temporal bones were harvested and prepared for histologic examination. None of the 15 controls demonstrated middle ear abnormalities. In the experimental group, 77% of temporal bones showed middle ear pathology consisting of either of subepithelial edema (27%) or frank otitis media (50%). These results indicate that the guinea pig is a suitable species for study of otitis media in association with vitamin A deficiency. We postulate that eustachian tube dysfunction is the primary mechanism for inducing middle ear inflammation in this animal model.


The gonadotrophin receptors: insights from the cloning of their cDNAs. The cloning and expression of the cDNA's for the gonadotrophin hormone receptors has confirmed that these receptors are each composed of a single polypeptide which can both bind hormone and activate adenylyl cyclase when occupied with agonist. Although some studies by others have suggested that the LH/CG receptor and the FSH receptor are composed of multiple subunits (Ascoli and Segaloff 1989; Reichert and Dattatreyamurty 1989; Shin and Ji 1985a, b, and c; Smith et al. 1985; Smith et al. 1986), biochemical studies on the LH/CG receptor have shown that it is composed of a single polypeptide with a molecular weight of 93,000 when analyzed on sodium dodecyl sulfate gels in the presence or absence of disulfide reducing agents (Ascoli and Segaloff 1989). As the LH/CG receptor has been shown to be readily proteolyzed into smaller-sized fragments (Ascoli and Segaloff 1986; Ascoli and Segaloff 1989), it is reasonable to postulate that the FSH receptor may be similarly susceptible to proteolysis, and that this may account for the discrepant reports on its structure. Clearly, the molecular cloning and functional expression of the cDNA's for the rat ovarian LH/CG receptor (McFarland et al. 1989) and the rat testicular receptor (Sprengel et al. 1990) demonstrate conclusively that the gonadotrophin receptors are indeed single polypeptides. As shown schematically in Fig. 5.12, the gonadotrophin hormone receptors (together with the thyrotrophin receptor, see Frazier et al. 1990; Libert et al. 1989; Nagayami et al. 1989; Parmentier et al. 1989) define a unique subclass of G protein-coupled receptors. Thus, in addition to the seven membrane-spanning domains which appear to be the hallmark of G protein-coupled receptors, the gonadotrophin receptors (and thyrotrophin receptor) also contain large extracellular domains. These extracellular domains are composed of a repeating leucine-rich motif which is found in a number of widely-diverse proteins, collectively termed leucine-rich glycoproteins. We have shown that the extracellular domain of the LH/CG receptor is entirely responsible for binding hormone with high affinity. This is in contrast to the rhodopsin-like G protein-coupled receptors which have relatively small amino-terminal extracellular domains and in which the ligands interact directly with amino acids within the transmembrane helices. As with other G protein-coupled receptors, however, it is thought that the gonadotrophin receptors interact with and activate Gs through residues located within the cytoplasmic loops and the amino-terminal region of the cytoplasmic tail.(ABSTRACT TRUNCATED AT 400 WORDS)


Behavioural endocrinology and reproduction: an evolutionary perspective. It is a fact that those interested in immediate causation tend to be unaware of the great advances in evolutionary biology. Similarly, most scientists interested in ecological and evolutionary questions ignore advances in neurobiology and molecular biology. Quite simply, 'reductionists see little to be gained from holistic studies, and whole organism biologists do not recognize the value of molecular analysis' (Prosser 1986). This philosophical gap and lack of communication between molecular and physiological biologists with organismal and evolutionary biologists makes it difficult to be a generalist. Yet if we are to understand past, present, and perhaps even future behaviour, we must study how the different levels of biological organization are integrated. If done with foresight, it can lead to new discoveries not only in evolution and ecology, but also in physiology and even molecular biology. One of the first things we are impressed by is the great variety of animals, particularly their behaviours and their physiologies. With so many differences, are there any generalities? With the establishment of evolutionary theory, evidence that there is 'unity in diversity' has come with discoveries of common anatomical features, the cell cycle, conservation of intermediary metabolism, and the genetic code, to name but a few. While in vertebrates there appears to be a conservation of the neural circuits underlying sex behaviour, it is still too early to state the extent to which this concept can be extended to the hormonal mechanisms underlying behaviour. This chapter has documented how some widely-held assumptions are generalities only in a very restricted sense. I have tried to show how much of our conceptual understanding of the behavioural endocrinology stems from extensive studies on relatively few species. According to (Beach 1979), there are '... two cardinal rules that should govern not only the construction of animal models for human behaviour, but for all interspecific comparisons regardless of the behaviour and the species involved. The first rule is that meaningful comparisons are based not upon the formal characteristics of behaviour, but upon its causal mechanisms and functional outcomes.... The second rule is that the validity of interspecific generalization cannot exceed the reliability of intraspecific analysis. Significant comparison of a particular type of behaviour in two different species is impossible unless and until the behaviour has been adequately analyzed in each species by itself.(ABSTRACT TRUNCATED AT 400 WORDS)


The chromosome complement of human gametes. The comparisons of observed and predicted rates of chromosomally abnormal gametes for two major classes of abnormality and for three specific trisomies are summarized in Table 2.10. As can be seen there is not very good agreement between the two sets of data. For sperm the observed abnormality rates are, with the exception of polyploidy, all in excess of those predicted. For structural abnormalities the excess is absurd and suggests that most structural abnormalities seen in sperm chromosomes may be preparation artefacts. On the other hand, it could be argued that the excess of hyperhaploidy among sperm is real and represents those trisomic conceptuses lost in the early stages of pregnancy. However, both chromosome 21 and the sex chromosomes are represented more often than any other chromosomes. Recent observations among all clinically recognized pregnancies do not suggest an excess of trisomy 21 conceptions arising from non-disjunction in spermatogenesis. As can be seen from Table 2.10, the observed frequencies of trisomy 21 is 10 times greater than that predicted, a difference that seems too great to be accounted for by early pregnancy wastage. While the X chromosome does appear to undergo non-disjunction much more frequently than the autosomes during spermatogenesis, the increase is restricted to non-disjunction of the XY bivalent at the first male meiotic division. In this class the observed and predicted frequencies are rather similar and it is even possible that the observed excess in sperm is accounted for by early post-zygotic loss. However, with the exception of the 24, XY class, the distribution of individual chromosomes among the hyperhaploid sperm bears little relation to that predicted. The most likely explanation for this is that banding of sperm chromosomes is of such poor quality that there are many errors in the identification of individual chromosomes. Most authors use some form of Q banding and this technique should give unequivocal identification of the highly-fluorescent Y chromosome even when other chromosomes are not clearly distinguishable. An increased accuracy of Y-chromosome identification may account for the relative concordance between observed and predicted rates of 24, XY sperm. By the same argument, 24, YY sperm might be expected to be accurately enumerated.(ABSTRACT TRUNCATED AT 400 WORDS)


DER revises waste management rules.

DER revises waste management rules. A number of improvements were made in new regulations designed to help physicians manage their infectious and chemotherapeutic wastes more easily. This article summarizes those improvements.


Restrictive covenants in physician employment agreements. Virtually all physician employment relationships are governed by employment agreements in which the physician and employer exchange promises. When embodied in contracts, promises are also known as "covenants." Certain covenants are restrictive in nature, including, most notably, covenants which prohibit competition ("non-competes"). Legal considerations regarding non-competes in particular center around the law of restrictive covenants in general. This article identifies legal issues which exist with respect to restrictive covenants under Pennsylvania law and offers certain caveats with respect to the negotiation of the non-competition components of the physician employment agreements.


Estate planning: some first steps.

Estate planning: some first steps. After you've worked a lifetime to build an estate, it's possible for the federal government to snatch up to 55 percent of it away from your heirs, and this could happen even if you've made a will. Clearly, an estate not carefully and professionally planned is one destined for lawyers' pockets, the courts, and both federal and state taxes.


PRO myths vs. facts.

PRO myths vs. facts. One thing of which the Keystone Peer Review Organization may be rightfully accused is that we are boastful about our efforts to communicate with physicians and providers. We think we do as good a job of education as can be done, and we don't mind saying so. However, certain myths have formed in the minds of some of our fellow physicians which seem impossible to dispel.


[Scoliosis and spondylolisthesis in children and adolescents]. The genuine structural scoliosis is characterized by a rotation of the vertebral bodies. Clinically suspect cases require an exact radiographic assessment. Treatment is based on the radiographically found COBB-angle: physiotherapy, brace and different types of surgical instrumentation are the most common therapeutic procedures. Early diagnosis is essential for the final therapeutic result! Spondylolisthesis can only be diagnosed by X-ray. Surgical stabilization is necessary if pain, instability or progressive gliding are found. The extent of surgical procedures depends on the stage of the gliding process. Therefore early diagnosis is desirable.


[The Nutrition Commission of the Austrian Society of Pediatrics and Adolescent Medicine. Prevention of caries]. Effective preventive programs must be instituted early in the life of a child. The pediatrician plays an important role in preventive oral health care, because most children do not visit a dentist before 3 years of age. Fluoride therapy decreases the caries vulnerability of the tooth, oral hygiene measures are important to remove bacterial plaque, and dietary modifications reduce the number of carbohydrate exposures per day. Community water fluoridation is proposed in Austrian cities, because it continues to be the most cost-effective caries prevention measure available. As long as the population does not have access to optimally fluoridated water, dietary fluoride supplementation offers an effective alternative. The recommended dosage of fluoride supplements for children depends on the amount of fluoride present in their drinking water and on the child's age. Liquid fluoride supplements and chewable tablets are proposed for children between 0.5 and 3 years and children between 3 and 13 years, respectively. Home use topical fluorides and professionally applied topical fluorides are useful beyond 3 years of age. Teaching of oral hygiene measures should be continued in kindergarten and school. The 3-6 year-old children require parental assistance to achieve effective plaque removal. Semiannual dental visits should begin at the age of three and continue throughout childhood and adolescence. As far as the diet is concerned, the frequency of exposure to sugar appears to be the most important factor in the development of dental caries. It now appears that most sugars are nearly equally cariogenic in a pure form.


[The mid-growth spurt--a pre-puberty growth spurt. Review of its significance and biological correlations]. The MGS is a growth phenomenon during early childhood, expressed by a mild transitory acceleration of growth velocity between five and eight years of age. It appears to be more pronounced in boys than in girls. It is probably caused by the functional maturation of the adrenals ("adrenarche") which leads to an increased androgen production during this age. Interactions with the pituitary growth hormone, also presenting with increased secretion rates at this particular period, are very probable. A hypothesis is offered for the explanation of individual differences and distinctness of the MGS. Although the MGS cannot be interpreted as a very first step of puberty, some additional biochemical facts suggest fundamental changes in the organism. Therefore, the MGS could be regarded as a "marker" within the biological development of the child.


[Transverse fetal position syndrome--a combination of congenital skeletal deformities in the newborn infant]. We describe a pattern of connatal postural deformities observed in approximately 0.6% of otherwise healthy, mature newborn infants. It comprises unilateral flattening of the skull (dolichocephalus), ipsalateral mandibular hypoplasia and torticollis, deviation of the septum nasi, pes calcaneovalgus on one and pes adductus supinatus on the other side. The deformities occur in four distinct combinations attributable to the prenatal lie of the fetus: dorsoanterior or dorsoposterior, left or right oblique lie. The deformities respond well to manipulative therapy.


On the interaction between macrophages and developmental stages of Schistosoma mansoni: effect of muramyl tripeptide phosphatidyl ethanolamine (MTP-PE) treatment on mice survival and the generation of schistosomulicidal macrophages. Schistosomiasis is a chronic disease afflicting hundreds of millions of people throughout the world against which there is as yet no effective vaccine. In the present study we tested the effect of the immunomodulator muramyl tripeptide phosphatidyl ethanolamine (MTP-PE) on the survival of Schistosoma mansoni-infected mice and on the induction in them of schistosomulicidal macrophages. Mice exposed to 80 cercariae each and then treated with MTP-PE showed prolonged survival following either single or repeat infection. The treatment with MTP-PE, when initiated 70 days post the schistosome infection, diminished significantly the mortality of infected mice over an observed period of 110 days. In terms of treatment efficacy there was no evident difference between the intravenous and intraperitoneal mode of administration of the drug. MTP-PE treatment significantly reduced granuloma size and markedly diminished liver damaged as judged by the lower levels of alkaline phosphatase in the serum. Such treatment exerted no significant effect on the spleen or liver weight in infected mice nor on the worm burden resulting from either a single or double infection. In infected and non-treated mice, schistosomulicidal macrophages appeared after 8-10 weeks of infection. In infected mice treated with MTP-PE there was an accelerated appearance of such macrophages and these exhibited a greater cidal effect on the schistosomula. These immunostimulatory and life-prolonging effects of MTP-PE on S. mansoni-infected mice might indicate an effect of this reagent on cells involved in the granulomatous process.


Brugia pahangi infections in immune-compromised rats demonstrate that separate mechanisms control adult worm and microfilarial numbers. The immunological basis of resistance to Brugia pahangi infection in rats was studied. Infections were investigated in athymic rnu/rnu rats and in rats treated with the immuno-suppressive agents cyclosporin A (CsA) or cyclophosphamide (Cy). The recovery of adult worms in normal rats was 1-2% in comparison to 12.2% recovery in athymic rats. CsA and Cy treated rats did not have increased adult worm burdens. Microfilarial (Mf) levels (expressed as Mf per ml per adult worm) were highly elevated in both athymic and Cy treated rats but not in CsA treated rats. IgG and IgM levels to B. pahangi antigens were severely depressed in both athymic and Cy treated rats. IgG levels but not IgM levels were abrogated in CsA treated rats. These results implied that control of larval establishment or adult killing, and regulation of Mf levels are separate T-cell dependent mechanisms and act independently of IgG antibody. Control of Mf levels is associated with a specific IgM response which is Cy sensitive but CsA resistant.


Transmission blocking immunity to human Plasmodium vivax malaria in an endemic population in Kataragama, Sri Lanka. Serum effects on gametocyte infectivity, that is, transmission blocking/enhancing immunity, were measured in the sera of 196 acute Plasmodium vivax patients who were residents of a malaria region in Kataragama, southern Sri Lanka. Direct mosquito feedings were also performed on 170 of these patients. Sera of about 48% of patients suppressed gametocyte infectivity significantly (by more than 75%) and of a smaller proportion (12%) had pronounced infectivity enhancing effects. Transmission immunity did not increase with age of patients, rather, immunity tended to be higher in younger patients. Data suggest that immunity levels are boosted by reinfections only if they occur within a period of 4 months from the previous infection, i.e., that immune memory for boosting does not last beyond 4 months. Enhancing effects in the sera of patients correlated with the absence of gametocytes at the time of investigation suggesting that enhancement occurs early during the course of a blood infection, and blocking later, when serum antibodies reach higher levels. The blocking and enhancing effects of serum appears to depend not only on the antibody concentration in serum, but also on the intrinsic infectivity of the parasite isolate against which it is tested: thus, infectivity enhancing effects were potentiated by low intrinsic infectivities of the parasite isolate. The direct infectivity of patients to mosquitoes correlated with transmission immunity indicating that transmission immunity is an influential factor determining infectivity of malaria patients.


In vivo activation of macrophages by IFN-gamma to kill Entamoeba histolytica trophozoites in vitro. To determine the role of interferon-gamma (IFN-gamma) in the activation of macrophages to kill Entamoeba histolytica trophozoites in vitro, C57BL/6 mice were injected with various doses of recombinant IFN-gamma (rIFN-gamma) by either the intravenous, intraperitoneal or intramuscular routes. Mice were treated with doses of rIFN-gamma ranging from 10(1) to 10(5) units. Twenty hours later, peritoneal macrophages were harvested from the treated animals. Macrophage monolayers were prepared and their in vitro cytotoxic activity against a virulent strain of E. hystolytica (IP:0682:1) was determined. Amoebicidal activity was determined by counting the number of dead trophozoites by Trypan Blue exclusion in cultures containing macrophages and amoebic trophozoites which were incubated together for 4 h. Both intravenous and intraperitoneal treatment resulted in the recovery of macrophages from the peritoneal cavity which exhibited amoebicidal activity in vitro. Peritoneal macrophages harvested from mice that had been treated intraperitoneally or intravenously with rIFN-gamma, however, showed significantly more amoebicidal activity in comparison to macrophages harvested from animals treated intramuscularly. There was a dose dependent relationship between the concentration of rIFN-gamma used to activate macrophages in vivo and the number of dead trophozoites in vitro. In addition, these results confirm our previous observations that treatment in vitro with rIFN-gamma can activate murine peritoneal macrophages to kill amoebic trophozoites.


Detection of cytokine mRNA in the brains of mice with toxoplasmic encephalitis. C57Bl/10 ScSn mice infected with Toxoplasma gondii developed a meningoencephalitis, characterized by areas of tissue destruction and cellular infiltration including foci of neutrophils. Large numbers of cyst stages were found throughout the brain but were not always associated with inflammation. The use of immunocytochemistry to detect glial fibrillary acidic protein, an astrocyte specific marker, showed a widespread astrocyte activation. This was particularly prominent in areas of intense inflammation but cysts were negative for glial fibrillary acidic protein, indicating that astrocytes were not host cells for the bradyzoites. The use of the polymerase chain reaction to assist in the amplification of total brain RNA allowed the characterization of the cytokines being produced locally within the brains of infected animals. beta-actin transcripts were detected in all of the uninfected and infected mice. In only one of the seven uninfected control mice were other transcripts found. Transcripts for tumour necrosis factor-alpha, interleukin-1 alpha and beta, interleukin-6, macrophage inflammatory protein-1 and interferon-gamma as well as the CD4 marker were detected in all of the infected mice. However, transcripts for IL-2 and IL-4 were not present. Several of the cytokines present are capable of initiating meningeal inflammation and may play a role in the immunopathogenesis of toxoplasmic encephalitis.


Changes in the protein profile and antigenicity of different Borrelia burgdorferi strains after reintroduction to Ixodes ricinus ticks. Eight Swiss strains of Borrelia burgdorferi, with various protein profiles and the North-American strain B31 were artificially introduced into Ixodes ricinus ticks and reisolated 10 days later. All isolates were subsequently examined by SDS-PAGE analysis. Comparing initial isolates with the reisolates, we observed that 7 out of 9 strains changed their protein pattern with respect to the major proteins OspA, OspB and the 22 kDa protein after passage in the tick. The strains NE2, NE4 and NE83 with the initial phenotype of OspA and 22 kDa proteins changed to the phenotype of OspA and OspB, the strains B2 and NE202 with the initial phenotype of OspA acquired an additional protein of 22 kDa and the strain NE58 with the initial phenotype of OspA also acquired a protein of 22 kDa. Examination of these isolates by Western blot analysis demonstrated that the reaction with the monoclonal antibody H5332 and a monospecific polyclonal antibody PoAb/anti-22 kDa differed between the initial isolates and the reisolates.


The influence of challenge dose, duration of immunity, or steroid treatment on mucosal mast cells and on the distribution of sheep mast cell proteinase in Haemonchus-infected sheep. The distribution of granule-specific sheep mast cell proteinase (SMCP), was assayed by immunocytochemistry and quantified by immunoassay in sheep immune to Haemonchus contortus. Repeated infection with Haemonchus larvae over 10-12 weeks induced a pronounced mucosal mastocytosis, including intraepithelial globule leukocytes (GL), which, 7 days after ceasing this dosing regime, was associated with the inability of incoming larvae to establish within the abomasal mucosa. Loss of this resistance, due to the cessation of stimulation with Haemonchus larvae 84 days previously or to treatment of sheep with corticosteroid, was associated with a marked decline in mast cell density and concentrations of SMCP in abomasal mucosal tissues. Nevertheless, larvae also failed to establish in immune sheep rested from challenge 42 days previously and in which mast cell counts were not significantly different from those of control sheep. A small, but significant, release of SMCP was demonstrated in gastric mucus from immune sheep following larval challenge, whereas little or no SMCP was detected in mucus from naïve animals.


Modulation of cytokine production and response phenotypes in murine trichuriasis. BALB/K mice are usually resistant to infection with the intestinal nematode parasite Trichuris muris and exhibit a Th2 dominated (IL-5, IL-9) response. Conversely in B10.BR mice, which are unable to expel T. muris, Th1 type (IFN-gamma producing) cells predominate. We have manipulated the course of infection in these two strains of mice such that the period of host-parasite contact is extended in the former and curtailed in the latter. Extension of host-parasite contact in BALB/K mice beyond normal (day 21) resulted in the modulation of cytokines produced by in vitro concanavalin A (Con-A) stimulated MLNC away from IL-5 and IL-9 (Th2-type cytokines) in favour of the Th1-type cytokine IFN-gamma. Curtailment of host parasite contact in B10.BR mice to less than 21 days resulted in elevated production of IL-5 and IL-9 by MLNC in the absence of elevated IFN-gamma levels. Thus modulation of expulsion phenotype also modulates cytokine production by T-cells in the MLN draining the site of infection, with a Th2 response being associated with resistance and a Th1 type response with the inability to expel the parasite. Mechanisms by which the modulated cytokine profiles arise are discussed.


Transmission blocking antibody of the Plasmodium falciparum zygote/ookinete surface protein Pfs25 also influences sporozoite development. The Plasmodium falciparum zygote/ookinete surface protein, Pfs25, persists in the oocyst wall throughout its development. Anti-25 kD transmission blocking antibody, given to infected Anopheles stephensi or A. gambiae mosquitoes in an additional bloodmeal, 3-6 days after being fed gametocyte infected blood, penetrated the oocyst and reacted with the 25 kD protein within it. This reaction caused a significant reduction in the number of developing sporozoites. Mouse serum containing antibodies raised by immunization with a recombinant 25 kD yeast product showed a similar effect.


An immunocytochemical test for the diagnosis of antibodies to Plasmodium vivax. An immunocytochemical peroxidase test (ICPT) has been developed to allow serological measurement of the antibody response to Plasmodium vivax by light microscopy. Acetone fixed P. vivax erythrocyte stages were used as source of antigen. The immunofluorescent antibody test (IFAT) was used as reference test. In testing sera from individuals infected with P. vivax in southeastern Venezuela a high correlation (100%) was obtained between the ICPT and the IFAT. There were cross reactions with sera from patients with malaria by P. falciparum but not with those from patients with other parasitic diseases. Antibody titres as measured by the ICPT showed a positive correlation with past P. vivax malarial experiences.


Occurrence and characteristics of hypodense eosinophils in rats infected with Trichinella spiralis. Hypodense eosinophils are observed in peripheral blood and tissue from patients with eosinophilia due to helminthic infections. In this study, the variation in eosinophil density was examined in rats during Trichinella spiralis infection. Hypodense eosinophils were observed in the peripheral blood in association with Trichinella infection. In peritoneal fluid, which was representative of tissue fluid, a majority of eosinophils were hypodense regardless of the infection. During the course of tissue eosinophilia after the infection, there was a particular increase in the lowest dense cells in the population of hypodense eosinophils. Eosinophils with lower density, demonstrated larger diameters and had more potent cytotoxic activity.


Inhibition of protein synthesis in irradiated larvae of Schistosoma mansoni. UV-irradiated and gamma-irradiated schistosomula of Schistosoma mansoni induce high levels of resistance to challenge infection in experimental hosts. It was observed that both types of irradiation severely inhibited protein synthesis by the parasite larvae. Schistosomula were treated with the metabolic inhibitor actinomycin D to simulate this effect of irradiation. The ability of these drug-treated larvae to induce immunity was tested in animal protection experiments. Our results suggest that inhibition of protein synthesis may help to generate the enhanced immunogenicity of irradiated schistosomula. In explanation, we propose that irradiated schistosomula may be such potent immunogens because they express antigens in disrupted, abnormal conformations. Inhibition of protein synthesis may both directly create such modified antigens, and also ensure that they persist and accumulate for presentation to the host immune system.


Demonstration of Leishmania specific cell mediated and humoral immunity in asymptomatic dogs. An ELISA and a lymphocyte proliferation assay were used for the detection of anti-Leishmania antibodies and parasite specific cellular immunity respectively in a preliminary study of canine leishmaniasis in Oporto, Portugal. A high rate of infection was found considering the comparatively small group sampled. Of 34 dogs examined two had anti-leishmanial antibodies but their lymphocytes did not proliferate in the presence of Leishmania infantum. Conversely two dogs demonstrated antigen specific lymphocyte proliferation in the absence of any detectable anti-parasite antibodies. To our knowledge this is the first time that cellular immunity and presumably resistance of dogs to leishmanial infection has been demonstrated. These results suggest that there may be a spectrum of canine leishmaniasis similar to that observed in the human disease.


Antibody-dependent cell-mediated immune reactions to Loa loa microfilariae in amicrofilaraemic subjects. Antibody-mediated mechanisms that could be important in controlling microfilaraemia in Loa loa infected amicrofilaraemic adults (mf-ve) were studied. These subjects were selected as having a verified ocular passage of an adult L. loa but being amicrofilaraemic and without recent diethylcarbamazine treatment. Sera from 37 mf-ve subjects were compared to 14 sera from heavily (greater than 4000 mf/ml) infected subjects (mf+ve) and 9 sera from Caucasian control subjects for their reactions with L. loa mf (mf). Many mf-ve sera (22/37) were strongly positive in immunofluorescence (IFAT) on living mf. Mf+ve sera were negative, or only weakly positive, and Caucasian sera were negative. Clinical signs were not significantly different between IFAT reactive and non-reactive mf-ve subjects. Approximately half of the IFAT positive, mf-ve sera were also able to agglutinate mf; no other sera were active in this test. Titres ranged from log2 3-6 and in most cases, 9/11, the agglutination reaction was mercaptoethanol-sensitive. Antibody-dependent cellular adherence was studied using mf and leukocytes from uninfected donors. Using cryopreserved mf many heat-inactivated mf-ve sera gave strong reactions with obvious adherence by 4 h and few motile mf remained by 16 h but when fresh mf were employed these reactions were weak. However, addition of complement to many (10/11) mf-ve sera considerably enhanced adherence to fresh mf. The effect of various treatments on the complement source indicated a role for both the classical and alternative pathways. The cells attached to mf were mainly neutrophils (83%) with some eosinophils (15%) and few mononuclear cells (2%). The common occurrence of antibodies able to mediate complement-dependent adherence of polymorphonuclear leukocytes to L. loa mf in the sera of mf-ve subjects may indicate that such a mechanism is important in controlling microfilaraemia in vivo.


The influence of adjuvant on humoral responses to glutathione-S-transferase fusion proteins. Mice were immunized with one of two Schistosoma mansoni antigens, Sm20 and Sm50, expressed as fusion proteins with Schistosoma japonicum 26,000 Dalton glutathione-S-transferase (GST) or with GST alone. Antibody responses to GST were shown to be critically dependent on the adjuvant used. In Sm20-GST immunized mice, we noted a striking bias to respond either to Sm20 or to GST according to the adjuvant used and responses to both in the same individual were rare. Fusion with Sm50, which is relatively non-immunogenic, appeared to down-regulate responses to GST.


Management of open fractures.

Management of open fractures. An open fracture is an orthopaedic emergency that can lead to devastating complications and prolonged rehabilitation. The goals of treatment are to prevent infection, achieve bone union, and restore function. The treatment should involve the use of antibiotics, repeated thorough irrigation and debridement, early fracture stabilization, early wound closure, and aggressive rehabilitation. The result of treatment is largely affected by the initial soft-tissue loss, wound contamination, fracture stability, and neurovascular status.


2-D and 3-D computed tomography and magnetic resonance imaging in developmental dysplasia of the hip. Clinical examination and plain roentgenograms have been the main methods of diagnosis and treatment of developmental dysplasia of the hip. Occasionally, concentric reduction cannot be achieved, or the reduction is questionable. A dynamic arthrogram can add more information but is usually performed under general anesthesia. "Mini" computed tomographic imaging demonstrates the femoral head-acetabulum relationship more accurately and produces minimal radiation. Three-dimensional computed tomography is useful in older children, in whom all sections are ossified. Magnetic resonance imaging, particularly 3-D magnetic resonance imaging, demonstrates the nonossified structures. It is the best method of visualization in developmental dysplasia of the hip. The disadvantages of this method include its cost and the lack of dynamic imaging. In the future, new software will overcome these shortcomings.


Plaster cast versus Clyburn external fixation for fractures of the distal radius in patients under 45 years of age. In this prospective study, 70 patients between the ages of 20 and 45 years with comminuted intra-articular fractures of the distal radius of types III to VIII (graded according to Frykman) were treated either by closed reduction and forearm plaster (35 patients) or by application of a Clyburn dynamic external fixator (35 patients). The external fixator was more effective at holding the manipulated position, and the roentgenographic loss of position during fracture union was minimal compared with that seen in patients treated in plaster. Functional results in the fixator group were 18 excellent, 10 good, 6 fair, and 1 poor. The plaster group showed the following functional results: 12 excellent, 8 good, 10 fair, and 5 poor. The external fixator generated significantly better anatomical and functional results than did treatment with forearm plaster. A good anatomic position combined with early rehabilitation of the wrist function produced very favorable functional results in patients less than 45 years of age.


Clinical experience with unreamed locked nails for open tibial fractures. Open fractures of the tibia remain a formidable injury. External fixation has been the mainstay of treatment for the more severe fractures. This treatment option, however, is not without significant complications. Of particular importance is the rate of infection once the fixator is converted to a reamed intramedullary nail in cases of delayed union or nonunion. A retrospective review of the records of 20 patients who underwent unreamed, interlocked, intramedullary nailing for tibial fracture has shown that unreamed tibial rodding offers an excellent alternative to external fixation for the management of Grades I and II open tibial fractures. Additionally, for Grade III open fractures, this serves as an excellent form of preliminary stabilization, allowing the soft-tissue injury to heal.


Compartment pressures of the leg following intramedullary fixation of the tibia. A prospective study was performed to determine whether compartment pressures of the leg were affected by intramedullary fixation of the tibia. Ten of the 11 patients studied had surgery for acute diaphyseal fractures and 1 for tibial nonunion. Compartment pressures were measured immediately prior to the procedure and at 12 hours after the procedure. There was no difference between the preoperative and postoperative compartment pressures. Our data suggest that intramedullary stabilization of the tibia does not predictably increase compartment pressures.


Scaphoid enchondroma.

Scaphoid enchondroma. Enchondromas are rarely found in carpal bones. This paper reports a case with scaphoid enchondroma and reviews three cases from previous literature. Three of the patients with scaphoid enchondromas presented with pathologic fractures after traumatic events. Each enchondroma had characteristic histopathologic findings. It is important to realize that although enchondroma is usually a painless lesion, it weakens the cortex of the involved bone, facilitating fracture. Thus, when cystic scaphoid fractures are encountered, enchondroma must be part of the differential diagnosis.


Technical tips for the fixation of supracondylar femur fractures with the sliding screw-plate device. Supracondylar fractures of the femur are common injuries. When open reduction and internal fixation are required, these fractures become challenging problems. We present four technical tips that help the surgeon obtain good results when open reduction and internal fixation with the screw- and side-plate device are chosen.


A 35-year-old man with right wrist pain. The following is presented to illustrate the roentgenographic and clinical findings of a condition of interest to the orthopaedic surgeon. The initial history, physical findings, and roentgenographic examinations are found on this page. The final clinical and roentgenographic differential diagnoses are presented on the following pages.


The role of calcitonin treatment in postmenopausal osteoporosis. Synthetic salmon calcitonin (SCT) is a potent antiosteoclastic hormone with adjunctive stimulatory effects on osteoblastic function. It is capable of increasing or stabilizing bone mass in osteoporosis and thereby can lessen the risk of fractures. Treatment doses vary from 100 IU daily to 50 IU three times a week, and the duration of treatment is 2 to 5 years. SCT also exerts an analgesic effect on the skeleton that increases its beneficial effect. Side effects, which do not involve organ toxicity, are common but are usually mild and transient. More severe side effects can be managed by maneuvers such as bedtime dosing, premedication, and temporary dose reduction. Primary resistance occurs in approximately 25% of patients and secondary resistance, usually due to neutralizing antibody formation, in 10% to 20% of patients. SCT is indicated in both early and late osteoporosis and is the treatment of choice in the latter.


Elbow arthroscopy.

Elbow arthroscopy. Elbow arthroscopy has made rapid advances in recent years. The improvement in the arthroscopic technique, as well as the development of technically advanced equipment, has made elbow arthroscopy very attractive to orthopaedic surgeons. It is important to realize that elbow arthroscopy is a modality that should be respected. This demanding procedure requires keen awareness of the elbow's anatomy and the technical arthroscopic approach to the elbow joint. With this careful approach in mind, the orthopaedist will find that elbow arthroscopy can be a valuable tool.


Femoral allograft reconstruction in revision total hip arthroplasty. Rigid graft fixation with cortical loading through the graft to protect from stress shielding is an important goal during femoral allograft reconstruction in revision total hip arthroplasty. Total proximal femur allografts require intramedullary prosthetic splinting and a step-cut osteotomy or extended lateral allograft plate for the most secure fixation and ultimate union. Nonunion and dislocation are the most critical complications, and infection rates are similar to other reconstruction procedures. This review discusses the principles and application of allografts in femoral revision total hip arthroplasty.


The current status of acetabular fixation in total hip replacement. Aseptic loosening of the acetabular component is the major long-term complication of cemented total hip replacement. In this article, the improvements in cementing technique and cemented acetabular component design, as well as the evolution of noncemented acetabular cups, are reviewed. The porous-coated acetabular component has emerged as the state of the art in both primary and revision hip arthroplasty. Current trends in porous cup design and implantation are presented. The ultimate fate of the porous ingrowth cup will be based on long-term clinical and roentgenographic follow-up studies.


Laser arthroscopy.

Laser arthroscopy. Lasers have become widely used in several medical and surgical disciplines. In ophthalmology and plastic surgery, their use has permitted the development of therapeutic modalities that would have been otherwise impossible. In such specialties as gynecology and general surgery, lasers provide advantages that make certain procedures more convenient and easier to perform. In contrast, orthopaedic surgeons have, to date, been slow to accept these devices into the therapeutic armamentarium. The purpose of this paper is to describe the status of laser use in the orthopaedic subspecialty of arthroscopy.


Transient osteoporosis of the hip misdiagnosed as osteonecrosis on magnetic resonance imaging. A 34-year-old man developed idiopathic, bilateral, asynchronous transient osteoporosis of the hip. The symptoms included hip pain with activity, and roentgenography revealed osteoporosis of the femoral head and neck. Radionuclide bone scans showed increased uptake of the involved femoral head. Magnetic resonance imaging (MRI) early after the onset of right-side symptoms was characterized by decreased signal intensity on T1-weighted images and patchy areas of increased and decreased signal intensity on T2-weighted images; this was initially interpreted as being consistent with osteonecrosis. Despite evaluation by multiple physicians and imaging methods, including MRI, the correct diagnosis of transient osteoporosis of the hip was delayed until after resolution of the syndrome. Transient osteoporosis of the hip should be included in the differential diagnosis of hip pain.


Long-term follow-up of a total articular resurfacing arthroplasty and a cup arthroplasty in Gaucher's disease. Patients with Gaucher's disease, a well-described lipid storage disorder with many systemic manifestations, often present to the orthopaedic surgeon with osteonecrosis of the femoral head. This can be a difficult orthopaedic problem because of the patient's young age at presentation and abnormal bone stock. Review of the literature leaves uncertainty as to the ideal treatment of femoral-head avascular necrosis in this disease. This article reports the long-term results of a cup arthroplasty and a total articular resurfacing arthroplasty procedure for bilateral hip involvement. In light of the less-than-satisfactory results of total hip arthroplasty for young patients with Gaucher's disease, resurfacing arthroplasty may warrant more serious consideration. For the older patient with Gaucher's disease, total hip arthroplasty may be preferable.


Removal of broken distal interlocking screws. Existing techniques for removing broken distal interlocking screws can involve trephine over-cutting of the screws, which requires bone exposure and creates larger stress risers by enlarging the original screw hole. We present a technique for removal of these screws that takes advantage of both the design of interlocking screws and the bone quality in the area of their placement. In this technique, a guide-wire "punch" is used to drive the screws through the medial cortex and soft tissue for removal through a small medial incision.


Evidence for the existence of ganglioside molecules on Pneumocystis carinii from human lungs. This study was undertaken to assess whether glycolipid antigens (particularly gangliosides) are associated with Pneumocystis carinii obtained from human lungs. Gangliosides were extracted, purified in high performance thin-layer chromatography and stained with resorcinol. Two resorcinol-positive bands, co-migrating with GM1 and GD1a were demonstrated, suggesting the existence of ganglioside molecules on P. carinii. No resorcinol-positive bands were revealed in the pulmonary control tissue. In addition, an antiserum obtained from rabbits immunized with P. carinii antigen reacted with gangliosides GM1 and GD1a, as revealed by a dot immunobinding assay. This reactivity was inhibited by first incubating the antiserum with ganglioside micelles. Furthermore, anti-glycosphingolipid antibodies (aGM1) reacted with the bands of 200 and 55 kDa of P. carinii antigen. These results suggest that ganglioside antigens expressed on P. carinii can trigger specific immune responses.


Vegetation structure influences the burden of immature Ixodes dammini on its main host, Peromyscus leucopus. To determine whether the relative abundance of immature Ixodes dammini (the vector of Lyme disease and human babesiosis) is related to habitat structure, we examined tick burdens on their main host, the white-footed mouse (Peromyscus leucopus), in 4 structurally diverse sites on Great Island, Massachusetts, USA. Vegetation structure at each site was quantified with respect to 25 habitat variables. Principal components analysis was used to reduce this set of habitat variables to seven new and orthogonal variables. Immature tick abundance varied widely among grids. Regression analysis of tick burdens on the habitat principal components showed that larval burdens were related strongly to the density of woody vegetation and negatively to herbaceous vegetation. Nymphal burdens were related negatively to herbaceous vegetation, but the relationship was not as strong as in the case of larvae. An experimental reduction in the abundance of white-tailed deer (Odocoileus virginianus), the main host of adult ticks, substantially reduced tick burdens and altered their relationships to habitat structure. Nymphal burdens were unrelated to habitat structure following deer removal. Manipulating habitat structure may have utility as a control strategy against this important vector.


Trichinella strain, pig race and other parasitic infections as factors in the reliability of ELISA for the detection of swine trichinellosis. An enzyme-linked immunosorbent assay (ELISA) using crude worm extracts (CWE) and mixtures of these as antigens of five Spanish isolates (P, C, B1, B2 and W) was developed for detecting homologous and heterologous experimental infections with these isolates between-14 and 82 days post-infection (p.i.) in white and Iberian pigs. A total of 243 pigs (Iberian or cross-bred with this race) with numerous parasitic infections were also screened for the presence of antibodies to a mixture of CWE of C, B1 and B2 isolate. The test showed a specificity of 93.1-98.9% depending on the cut-off values and a maximum sensitivity of 92.8-100% between days 34 and 82 p.i. A low grade of infectivity was shown in the T3 isolates compared to the T1 isolates (P, C, B1 and B2) but high cross-reactions were observed between all the isolates with minor differences between P and W isolates. The highest antibody response was found in P infections and the lowest in pigs infected with the W isolate. A clear association between the presence of several parasitic infections and false positive reactions was not found, but an important relation was shown between high background levels and the Iberian race in experimentally and conventionally raised pigs.


Genetic influences upon eosinophilia and resistance in mice infected with Trichinella spiralis. Genetic influences upon host variation in eosinophilia and resistance to helminth infection, and the relationship between these parameters, were investigated in 7 inbred and 1 hybrid strains of mice infected with Trichinella spiralis. Clear strain-dependent variations were observed in the maximum peripheral blood, bone marrow and spleen eosinophilia attained in infected animals. SWR, NIH and SJL strains of mice all gave high responses to infection; four congenic strains sharing the B10 background (C57BL10 [B10], B10.S, B10.G and B10.BR) were low responders. Some of the genes for high responsiveness appeared to be dominant, as F1 hybrids from high- and low-response phenotype parental strains showed intermediate to high responses to infection. Intestinal eosinophilia showed no correlation with either peripheral blood or bone marrow responses (NIH and B10 strains having similar levels of eosinophil response in gut tissue) and was unrelated to the level of resistance to infection. Whereas NIH were highly resistant, with adult worm burdens at 13 days post-infection and muscle larval burdens at 35 days post-infection significantly lower than all other strains, B10 were quite susceptible, retaining substantial worm burdens at day 13 and harbouring large numbers of muscle larvae. Measurements of the level of the eosinophilopoietic cytokine IL-5 in sera during infection showed that the two strains differed in the kinetics of release but not in their absolute capacity to produce this cytokine. NIH mice released high levels during a primary infection, B10 released high levels during a secondary infection.(ABSTRACT TRUNCATED AT 250 WORDS)


Variation in responsiveness to Trichinella spiralis infection in inbred rat strains. An analysis of interstrain variation between 12 inbred and 4 congenic rat strains in the expression of immunity against Trichinella spiralis is reported. All rat strains expressed strong rapid expulsion which resulted in the elimination of 88-98% of a challenge infection of muscle larvae. In contrast, substantial interstrain variation in the rate of adult worm expulsion in the primary infection was evident. By day 10 after infection, BUF and YO strains had less than 50 worms left in the intestine whereas BI and WKA strain rats had barely begun rejection, with approximately 1000 worms present in the gut for both strains. All other rat strains fell within these extremes in a continuous gradation. There was no clustering of rat strains into phenotypic groups with comparable worm burdens as seen with mice. The number of muscle larvae that established after the primary infection showed less variation than had adult worm burden in the primary infection and there was only a weak correlation of muscle larvae burden with numbers of intestinal adults present at 10 days. Comparison of MHC-matched or MHC-disparate rat strains on a PVG background suggested that non-MHC genes determined the principal adult worm rejection characteristics of a given strain. The absence of phenotypic variation in the expression of rapid expulsion in rats reinforces the biological distinction between rat rapid expulsion and the 'rapid expulsion' defined for mice.


The effects of age, temperature, light quantity and wavelength on the swimming behaviour of the cercariae of Cryptocotyle lingua (Digenea: Heterophyidae). Laboratory experiments indicated that the active life-span of the cercariae of Cryptocotyle lingua was temperature-dependent. An increase in water temperature and population age both correlated with a tendency for the organisms to become decaudate. The larvae were strongly photoresponsive to lateral light but with time, horizontal swimming rates (HSRs) from release point to light source progressively declined. When measured over a range of light quantities, HSRs peaked at 30 microM/m2/s. HSRs were also influenced by water temperature. A rapid increase occurred up to 15 degrees C after which there was a precipitous decline. HSRs to coloured light were negatively correlated with increasing wavelength. When offered a choice between colours, cercariae favoured the shorter wavelengths. The implications of these responses for successful transmission are discussed.


Protein content of CBA/Ca mouse diet: relationship with host antibody responses and the population dynamics of Trichuris muris (Nematoda) in repeated infection. The influence of host dietary protein on acquired immunity and intestinal helminth population dynamics during repeated infection was studied using the mouse-Trichuris muris experimental model. CBA/Ca mice fed a 2% (by mass) protein diet ad libitum maintained body weight during the experiment, but when fed diets containing either 4% or 16% (by mass) protein gained weight steadily. Infection with T. muris did not affect the growth of the latter mice but significantly reduced the growth of animals fed on the 2% protein diet. When repeatedly infected with either 5 or 50 eggs every 10 days, the mice fed the 2% or 4% protein diet accumulated adults in proportion to infection dose. The results show that this is due to both the establishment of larvae at each repeated infection and the survival of established adults. In contrast, very few worms were recovered from animals fed the 16% protein diet, principally as a result of the development of strong acquired immunity to reinfection. T. muris egg output/mouse increased with infection dose in animals fed the low protein diets, but no parasite eggs were detected in the faeces of hosts fed the 16% protein diet. Mouse antibody responses to adult worm excretory/secretory antigen were time- and infection dose-dependent in all 3 dietary groups. The major finding was that the specific antibody response was more intense, both quantitatively (serum OD levels) and qualitatively (antigen recognition by IgG1), in mice fed the low protein diets, even though they remained susceptible to infection. This study shows that host dietary protein deficiency, even at levels irrelevant to normal growth, can markedly potentiate the transmission of T. muris via alterations in host resistance. The high levels of antibody in susceptible animals suggest that this defect in resistance is unlikely to be due to nutrient deficiency-associated defects in humoral immunity.


Effect of intra-erythrocytic magnesium ions on invasion by Plasmodium falciparum. Exclusion of magnesium ions from resealed ghosts or their extraction from intact human red cells by means of an ionophore results in a reversible drop in susceptibility to invasion by Plasmodium falciparum merozoites in vitro. Resealed ghosts, containing magnesium-ATP and diluted cytosol, are invaded with high efficiency only when the original hypotonic lysis is carried out in the presence of magnesium ions. This effect is not related to the loss of membrane-associated constituents when magnesium ions are absent. Ghosts containing calcium ions, together with the protective agent, flunarizine, were essentially resistant to invasion; this effect is again at least partially reversible. A possible explanation of these phenomena is that entry of the merozoite may be inhibited by breakdown of the host cell phospholipid asymmetry, with the appearance of aminophospholipids at the outer cell surface.


Comparative prevalences of Ascaris lumbricoides, Trichuris trichiura and hookworm infections and the prospects for combined control. Programmes to control Ascaris lumbricoides, Trichuris trichiura and hookworm infections have often been targeted at each infection separately, but the advent of benign and broad-spectrum anthelmintics suggests that combined control may be feasible. The extent to which the infections co-occur in communities will determine the need for, and potential benefits of, such a combined approach. This paper examines the comparative distribution of the three geohelminths in different geographical areas and shows that A. lumbricoides and T. trichiura have closely related distributions, while hookworm infection is largely independent of the other two. These results indicate that many communities are at risk of disease from infection by more than one species of helminth. The similar distributions and epidemiological characteristics of A. lumbricoides and T. trichiura suggest that simultaneous control of these two parasites by the same strategy would be feasible and highly beneficial to communities. Multiple species control strategies which aim to control hookworm infection may require a more complicated protocol with more precise locality targeting.


Epidemiology of canine leishmaniasis: prevalence, incidence and basic reproduction number calculated from a cross-sectional serological survey on the island of Gozo, Malta. Assessment of the resilience of canine leishmaniasis to control or, more ambitiously, the effort needed to eradicate infection, requires an estimate of the basic case reproduction number (R0). This paper applies the theoretical results of Hasibeder, Dye & Carpenter (1992) to data from a cross-sectional survey on the Maltese island of Gozo in which dogs of known age, sex and occupation (pet, guard etc) were subjected to three different serological tests for the presence of specific antibody (IFAT, DAT and ELISA). Difficulties in interpreting these test results, and hence of determining the proportion of dogs infected, present the main obstacle to estimating R0: estimates are critically dependent on the choice of threshold separating seropositives from seronegatives. The data do, however, allow a robust comparative analysis of risk which shows that the force of infection experienced by working dogs is about three times higher than that of pet dogs, a degree of non-homogeneous contact which actually has little effect on estimates of R0. We suggest a cautious point estimate of R0 congruent to 11, and comment briefly on its significance for leishmaniasis control.


Mathematical modelling and theory for estimating the basic reproduction number of canine leishmaniasis. The paper describes a mathematical model for canine leishmaniasis and presents formulae which can be used to estimate the basic reproduction number, R0. The primary concern has been to devise methods of estimation which make best use of those data most easily obtained by fieldwork, e.g. surveys of prevalence in dog (by age) and sandfly populations. A range of formulae are offered which are more or less demanding of data, and which consequently give more or less precise estimates of R0. They include methods for assessing the influence on R0 of heterogeneous biting rates of sandflies on dogs, in which the essence of heterogeneous transmission can be captured merely by measuring relative rather than absolute contact rates.


Adhesion of Trichomonas vaginalis to plastic surfaces: requirement for energy and serum constituents. The ability of Trichomonas vaginalis to adhere to plastic surfaces in the presence of various agents and under different growth conditions was examined in wells of microtitre plates containing unsupplemented TYI medium or the same, with various supplements. Following incubation, the wells were thoroughly washed and adhesion was determined by microscopic counting of the adherent organisms. There was no detectable adhesion in the absence of both serum and carbohydrate. Optimal adhesion (about 10-20% of the total number of parasites) was obtained throughout the growth curve in culture media supplemented with either serum or serum Cohn fractions IV-I (rich in alpha-globulin) or IV-4 (rich in alpha + beta-globulin) and 25 mM glucose, maltose or fructose, but not in plates pre-coated with the Cohn fractions. Cohn fraction II + III (rich in beta + gamma-globulin) moderately enhanced adhesion while Cohn fractions II (rich in gamma-globulin) or V (albumin), fibronectin, Tamm-Horsfall glycoproteins and polylysine were without effect. Non-metabolizable sugars (methyl derivatives of glucose, mannose or fucose) did not support growth, but, surprisingly, enhanced adhesion. At 4 degrees C, the trichomonads were not able to adhere and pre-adherent organisms detached from the plastic surface. Optimal adhesion was obtained at a pH range of 6.5-7.5 but was already detectable at pH 5.5. Cytochalasin E markedly suppressed adhesion.(ABSTRACT TRUNCATED AT 250 WORDS)


Schistosoma mansoni: adult males and females differentially express antigens encoded by repetitive genomic DNA. Two repetitive DNA sequences have been characterized from Schistosoma mansoni which were transcribed into mRNAs and translated to give two families of cross-reactive proteins. One DNA element, which was present as a 230 bp Pst I fragment was arranged in tandem arrays of at least 17 copies in the genome. The second element, which could be localized to a 1800 bp Pst I fragment, was dispersed in the genome. The 1800 bp repeat was found on the mRNA encoding the 45 kDa polypeptide precursor of a potential surface antigen. This precursor was post-translationally modified to give a 50 kDa antigen (Sm50) which was expressed from the cercaria to the adult worm and in the egg. However, a proportion of this antigen was differentially modified in females and eggs to give a 60 kDa form. Two copies of the 230 bp repeat and one copy of the 1800 bp repeat were found on a second cDNA clone. The antiserum raised against the fusion protein of this clone recognized a family of cross-reactive proteins ranging from 14 to 70 kDa in size. The members of this family were also differentially expressed between the sexes. Consequently, two families of antigens have been identified which were both encoded by repetitive DNA elements and whose members were both differentially expressed in adult male and female worms.


Immunization against cerebral pathology in Plasmodium berghei-infected mice. The development of cerebral lesions in Plasmodium berghei-infected mice was dependent on the strain of mice and the size of the infectious inoculum. In particular, C57Bl/6J mice develop cerebral lesions when infected with low numbers of parasitized erythrocytes. By increasing the number of parasites in the infectious inoculum, the percentage of animals that develop cerebral malaria is decreased. Varying degrees of protection against the development of cerebral malaria can be obtained by several methods of immunization. (1) Injection of mice with large numbers of disrupted parasitized erythrocytes 1 or 2 weeks before the challenge infection (protection up to 70%). (2) A 2-day immunizing infection given 9 or 14 days before the challenge infection (protection up to 85%). (3) Injection of mice with plasmodial exoantigen preparations 1 week before the challenge infection (variable protection-rate, up to 100%). In all mice protected against cerebral malaria, parasitaemia is not affected by the immunizing treatment, indicating that protective mechanisms against cerebral malaria and parasitaemia are independent.


Fluorescent lipid uptake and transport in adult Schistosoma mansoni. Fluorescent lipophilic compounds can be used to label the surface membrane of Schistosoma mansoni by adding the compound in small amounts of organic solvents to aqueous medium in vitro. Under these conditions it is difficult to follow routes of distribution of the label. Here we have absorbed nitrobenzoxadiazolamine methylamino-(NBD)-ceramides to positively charged Dowex beads, and incubated the labelled beads with living parasites. The NBD-ceramide transfers to the surface membrane as a patch 50-100 microns in diameter, after which the label can be seen localized in the gut and in a very concentrated form in organelles within the oesophageal gland cells. Subsequently the labelled compound can be found in organelles within other body cells, including subtegumental cells. We show that the labelled ceramide has been transported from the patch in the surface membrane through internal membrane systems to the destination in the gut and oesophageal gland and not transported through the gut via the external medium. A different pattern was observed when NBD-cholesterol was used. The pharynx was rapidly labelled when NBD-cholesterol was added in medium with or without serum or attached to red blood cells only. Diffuse labelling of the surface membrane and oesophageal gland occurred. We have demonstrated a novel route of lipid transport within the parasite. The route requires the surface membrane to have very specialized regions to facilitate such transport.


Kinetic modelling of isometamidium chloride (Samorin) uptake by Trypanosoma congolense. Clones of Trypanosoma congolense which express resistance to the widely used trypanocide isometamidium chloride accumulate less of the drug than clones which are sensitive to drug treatment. A mathematical model has been developed which was able to predict theoretical lines representing the uptake kinetics in trypanosomes which were sensitive to isometamidium, as well as for resistant trypanosomes in which reduced accumulation was a result of either reduced uptake or enhanced efflux of the drug. Data from drug uptake experiments were then fitted to these theoretical lines. While the value for drug efflux could not be separated from the dissociation constant of the trypanosomes for isometamidium, it was demonstrated that reduced accumulation is not a result of reduced uptake of isometamidium by drug-resistant trypanosomes.


Sequence differences between histones of procyclic Trypanosoma brucei brucei and higher eukaryotes. Four histones, a, b, c, d from procyclic Trypanosoma brucei brucei, which show similarities with the amino acid composition of the core histones H3, H2A, H2B and H4, were isolated and cleaved with Endoproteinase Glu-C. The fragments were separated by FPLC reversed phase chromatography and a subset of the fragments (a5, a9, b6, c8, d3, d9, d11) was subjected to sequence analysis. A 54-71% identity was found in the sequences of the fragment c8 and the C-terminal half of H2B and of three fragments of protein d covering the N-terminal half as well as the C-terminal region of H4. The amino acid sequence of the fragment a9 showed a 57 and 54% identity with H3 sequences of Saccharomyces cerevisiae and Xenopus laevis. Neither the a5 nor the b6 sequence could be aligned with histone sequences of other eukaryotes. The significant differences of 21-48% between the T.b. brucei histone sequences and those of calf thymus histones, which are more pronounced than the differences of Tetrahymena pyriformis and the higher eukaryote, resulted partially from replacements of amino acids with different properties and indicate specific patterns of histone-histone and/or histone-DNA contact sites in the nucleosome of T.b. brucei. These differences, together with the lack of a functional histone H1, may be sufficient to explain the lack of a salt-dependent formation of the nucleosome filament into the 30 nm fibre, which reflects alternative methods of organizing and processing the genetic information in the nucleus of the protozoan parasite and which may be of chemotherapeutic significance.


The spectrum of presentation at autopsy of myocarditis in infancy and childhood. To characterize the clinicopathological presentation of patients with myocarditis coming to autopsy in childhood, 32 cases of histologically-proven myocarditis were obtained from the files of the Adelaide Children's Hospital. In 16 of the cases (Group A), myocarditis was the only significant finding and death was ascribed to this condition. In the remaining 16 (Group B) myocarditis was found in association with other severe disease processes. Clinical histories of the 2 groups showed sudden death to be a feature in 5 out of 16 cases in Group A, 3 of whom had no prodromal symptoms. Five patients in Group B also suffered sudden death, but this was associated with a variety of causes, including bronchopneumonia, and asphyxia. These cases demonstrate the variability in clinicopathological presentation of myocarditis in infancy and childhood and suggest that myocarditis should always be considered a possible diagnosis at autopsy in the pediatric age group, even in the presence of coincident lethal disease.


Parosteal lipomas: a new perspective.

Parosteal lipomas: a new perspective. Parosteal lipomas, benign adipose tissue tumors situated directly on bone cortex, are unusual neoplasms that appear to emerge from multidirectional mesenchymal "modulation" within the periosteum. These tumors have been described as "periosteal lipomas", "chondrolipomas of soft tissue" and "lipomas of nerves" but they are most commonly believed to originate from the periosteum. Although over 100 of such tumors have been described in the literature, they have not been the subject of a comprehensive review, nor their potential for chondroid modulation and enchondral ossification emphasized. A review of 14 parosteal lipomas from the Bone Tumor Registry, Armed Forces Institute of Pathology, indicates these tumors are frequently associated with chondroid and/or osseous modulation, which permits subclassification into 4 distinct variants. Each of the 4 subtypes (I: No Ossification; II: Pedunculated Exostosis; III: Sessile Exostosis; IV: Patchy Chondro-Osseous Modulation) is illustrated to demonstrate the morphologic basis for radiologic/pathologic correlation and subclassification. A brief overview of the literature and pathogenesis of this unusual lesion is presented and discussed.


Combined pathological and radiological study of the effect of atherosclerosis on the ostia of segmental branches of the abdominal aorta. A combined pathological and radiological study of descending aortae from 15 subjects from 2 to 80 yrs of age was conducted to investigate changes in the segmental vessels with advancing aortic atherosclerosis. There were (i) small hillocks of musculo-elastic intimal thickening adjacent to the apex (centre of the flow divider) in the ostia of the segmental vessels in young subjects, (ii) progressive intimal thickening, distortion and narrowing of the ostia of the segmental vessels (iii) obliteration or loss of some ostia in advanced atherosclerosis of the distal abdominal aorta and (iv) gross discrepancy in severity of atherosclerosis between the aorta and its branches, the intimal proliferation tapering rapidly in the branches and often being minimal in the outer part of their intramural courses. Distal ramifications exhibited occlusions which radiographically were probably embolic or possibly artifactual. Atherosclerosis was rarely of significant degree histologically within the proximal 2 cm of the segmental branches.


Delayed rupture of spontaneous tear of the ascending aorta--report of two fatalities. A spontaneous tear of the ascending aorta, with or without medial dissection, can cause sudden death from hemorrhage due to aortic rupture. Two representative cases are described. Review of the clinical history and pathological changes showed that the terminal event was delayed allowing healing and reactive changes to occur in the aortic wall. A pathologist confronted with a fatal case of aortic rupture should be aware that death is not always immediate. Recognition of this has medicolegal importance, particularly if medical management is questioned because of a missed clinical diagnosis.


A prospective study of the morphological aspects of tumor involvement of the pulmonary vessels. A prospective morphological study of tumor involvement of the pulmonary vessels (TIPV) was undertaken on 203 consecutive autopsy cases of malignancies. The lungs were removed as a block and 15 sections (3 from each lobe) were analyzed. Site of origin, histological type and staging of the tumor, topographic distribution of the tumor emboli in the lungs, right ventricular hypertrophy and dilatation, pulmonary infarct, pulmonary vascular sclerosis and lung metastases were recorded in each case. TIPV was detected in 84 (41.4%) cases, the highest frequency reported until now. In 28 cases, TIPV was considered to be the main cause of death. The breast, liver, and pancreas were primary sites in more than 50% of the cases in which TIPV was observed. TIPV was more prevalent in epithelial neoplasms and showed a strong correlation with advanced disease. There was no significant difference among topographic regions of the lungs. The cases with TIPV were correlated with a high frequency of right ventricular hypertrophy and dilatation, vascular sclerosis and pulmonary metastases but not with pulmonary infarcts.


Glomerulosclerosis and hyalinosis in rabbits. Histological appearances of remnant kidney in female New Zealand white rabbits undergoing left nephrectomy at 6 mths were studied. All 20 rabbits had evidence of previous Encephalitozoon cuniculi (E. cuniculi) infection. Half of the 10 uninephrectomized and 10 control animals completed 3 pregnancies before sacrifice (15 mths). Twelve of 30 kidneys at sacrifice showed focal and segmental hyalinosis and sclerosis (FSHS), a lesion not previously reported in rabbits. Four of 5 kidneys in both uninephrectomized pregnant and uninephrectomized virgin animals showed FSHS compared with 2 of 10 in both control pregnant and non-pregnant rabbits (p = 0.0026). More glomeruli were sclerosed in control pregnant (median 3.5%) than non pregnant animals (median 0.4%) (p < 0.005). Median right kidney weights per kilogram body weight were greater in previously nephrectomized animals (3.9 gm/kg) than controls (2.6 gm/kg), (p < 0.001). Absolute glomerular area was increased in hypertrophied kidneys, however, after correction for kidney weight, glomerular area was smaller in previously uninephrectomized animals than controls (p < 0.0001).


Peanut agglutinin (lectin from Arachis hypogaea) binding to hemopoietic cells: an immunophenotypic study using a biotin streptavidin technique. The lectin peanut agglutinin (PNA) was used to study the surface carbohydrate expression of galactose beta 1, 3, N-acetylgalactosamine by normal and malignant hemopoietic cells. Immunostaining was performed using biotinylated PNA and a streptavidin-alkaline phosphatase staining technique on 78 patients. The study was undertaken to enlarge on previous reports of lectin binding to cells of hemopoietic origin and to establish the potential role of biotinylated PNA as a component of an immunotoxin for in vitro purging of bone marrow in patients with multiple myeloma. In normals only monocytes, macrophages, centroblasts and plasma cells showed reactivity. Of the hematological malignancies, all cases of multiple myeloma were positive and non-Hodgkin's lymphoma cases with a large cell component had positive centroblasts. Two of 5 cases of acute myelomonocytic leukemia, one case of chronic myelomonocytic leukemia and one case of pleomorphic T cell non-Hodgkin's lymphoma showed PNA positive neoplastic cells. The reactivity of biotinylated PNA with centroblasts and plasma cells suggests that it may be of potential value when linked to a streptavidin-ricin conjugate in the in vitro purging of bone marrow of patients with multiple myeloma prior to autologous bone marrow transplantation.


Heparin-induced thrombocytopenia: laboratory investigation and confirmation of diagnosis. We report here on the usefulness of the 14C-serotonin release assay for the laboratory confirmation of the clinical diagnosis of heparin-induced thrombocytopenia syndrome (HITS). Over the past 3 yrs, some 140 individual serum samples have been tested in our laboratory for heparin-associated anti-platelet activity ('heparin antibodies'). These included sera from 54 selected (4 positive, 50 negative) controls and a group of 86 patients where the test was requested on clinical grounds. Of 20 patients derived from within our institution, 7 out of 8 patients (88%) with good clinical probability of HITS were confirmed to have heparin platelet antibodies by the serotonin release assay. In contrast, only 2 out of 9 patients (22%) with a low clinical probability of HITS were shown to be positive by this procedure, as were 2 out of 3 patients (66%) deemed to have an 'intermediate' clinical probability of HITS. In addition, screening of 50 serum samples forming a 'negative-control non-HITS' group (either patients on heparin therapy without thrombocytopenia, patients with non-heparin associated thrombocytopenia [eg. ITP*, other drug related], or normal laboratory volunteers), consistently failed to display heparin associated anti-platelet activity by the 14C-serotonin release assay. In addition to the good specificity and sensitivity described above, the 14C-serotonin release assay was found to be nearly twice as sensitive when compared to the platelet aggregation procedure, and it is therefore a useful diagnostic test for the confirmation of clinically suspected HITS.


Acceptance of class II major histocompatibility complex disparate skin grafts associated with suppressor cells and elevated Langerhans cell numbers. Class II major histocompatibility complex (MHC) molecules are only present on Langerhans cells (LC) in normal murine epidermis. Depletion of this antigen with the chemical carcinogen dimethylbenzanthracene (DMBA) causes I-E disparate B10.A(2R) congenic tail skin to be accepted permanently when grafted onto B10.A(4R) recipients. Adoptive transfer of spleen cells from these recipients into naive syngeneic hosts inhibited the ability of the host mice to reject untreated B10.A(2R) tail skin grafts. Hence DMBA-treated LC depleted I-E disparate skin grafts activate suppressor cells which did not inhibit BALB/c mice from rejecting a B10.A(2R) tail skin graft. In contrast, the tobacco derived carcinogen benzo(a)pyrene (BP) increased the number of epidermal LC but had no effect on either class I or class II MHC disparate skin graft survival time. This confirms that the number of class II MHC-positive LC is critical for the initiation of skin graft rejection; when the threshold level is attained graft rejection proceeds at a maximal rate that cannot be enhanced by raising the number of LC. The tolerant skin grafts had increased numbers of LC; this was not observed in syngeneic grafts and therefore may be related to the active suppression of immunity.


Development of trimethoprim-resistance in Salmonella typhi during therapy. A typhoid patient was infected with a fully-sensitive, plasmidless strain of Salmonella typhi which acquired resistance to kanamycin, sulfamethoxazole and trimethoprim during cotrimoxazole therapy. The resistant post-treatment strain harboured 4 plasmids of 62, 4.1, 3.8 and 3.0 Md in size. Kanamycin-, sulfamethoxazole- and trimethoprim-resistance were borne on a transferable 62 Md plasmid which was compatible with groups FI, FIme, FII, FIV, H1, H2, B, I1, I2, J, K, M, N, T, X, W and P. Sulfamethoxazole-resistance was also borne on the 4.1 Md plasmid. The 3.8 Md plasmid was not transferable; the 3.0 Md plasmid was transferable but did not confer antibiotic resistance. Excluding the strain described here, only 5 out of 35 other S typhi isolates contained plasmids. This is the first report of trimethoprim-resistant S typhi in Hong Kong.


Capnocytophaga canimorsus septicemia associated with cat scratch. A case is reported of Capnocytophaga canimorsus (formerly CDC group DF-2) septicemia following cat scratch in a patient with congenital asplenia. The case is of interest in that (1) the clinical presentation provided no indication as to the cause of the patient's illness. (2) C. canimorsus infection following cat bite or scratch has been reported far less frequently than following dog bite. (3) The clinical course of the illness may have been modified by previous and concurrent warfarin therapy.


Mycobacterium fortuitum endocarditis in a patient with chronic renal failure on hemodialysis. A case of infective endocarditis due to M. fortuitum in a 54 yr old female with chronic renal failure on hemodialysis is presented. Clinical, microbiological and autopsy findings are discussed.


Beta-lactamase induction by imipenem in Yersinia enterocolitica. Five strains of Yersinia enterocolitica belonging to 5 different biotypes were induced to beta-lactamase production with imipenem in broth culture at 28 degrees C. Strains belonging to biotypes 1A, 1B, 2 and 3 showed a 26 to 73 fold increase in beta-lactamase activity after 180 min in the presence of 0.5 mg/L imipenem. Biotype 4 strain, by contrast, did not show obvious enhancement of its beta-lactamase activity in the same experiments. Enzyme B in biotypes 1B, 2 and 3 and enzyme "B-like" in biotype 1A were shown to be responsible for the increase of the beta-lactamase activity, but neither enzyme nor any similar enzyme was found to be present in biotype 4 strain.


Implications of rDNA technology in the microbiology laboratory. The present and potential future roles in service and research microbiological laboratories of recombinant DNA (rDNA) techniques (nucleic acid hybridization, nucleic acid amplification, in situ hybridization, pulsed field gel electrophoresis) are described. Applications rDNA technology include the detection of micro-organisms; an approach to the understanding of their role in disease pathogenesis and provision of alternative strategies for studying the epidemiology of infectious diseases.


Bizarre parosteal osteochondromatous proliferation of the hand in a young man. We report a case of a solitary osteochondromatous tumor on the hand of a 38 yr old man. This had radiological and histological features distinct from an osteochondroma and demonstrated the features first described as bizarre parosteal osteochondromatous proliferation. These lesions have a tendency for local recurrence but no metastatic behaviour has yet been reported. We highlight 2 histological features which have not been previously described.


Papillary carcinoma arising in ectopic thyroid tissue within a branchial cyst. The first case of a papillary carcinoma arising in ectopic thyroid tissue within a branchial cyst in a 34 yr old woman is presented. This also adds to the existing list of unusual sites where ectopic thyroid tissue has been described. All histological types of carcinoma have been reported in ectopic thyroid tissue, papillary carcinoma being the most common histological type, accounting for 85% of these tumors. The criteria for establishing this diagnosis of carcinoma arising in ectopic thyroid tissue within branchial cyst is discussed.


Polyneuropathy, organomegaly, endocrinopathy, M-protein and skin change (POEMS) syndrome with IgG kappa paraproteinemia. The POEMS syndrome is an infrequently reported multisystem disorder which presents usually as an obscure polyneuropathy, with almost all cases reported in Japan. A 64 yr old caucasian man presented with a 12 mth history of a severe sensorimotor neuropathy in association with dermato-endocrine features. Detection of a monoclonal IgG kappa paraprotein and mixed osteosclerotic/lytic bone lesions consistent with a plasma cell dyscrasia led to diagnosis of the POEMS syndrome. Unique ultrastructural features were present on sural nerve biopsy in addition to the unusual association with monoclonal kappa-light chain. This case illustrates that the POEMS syndrome may also occur in caucasian subjects.