Renal cortical scintigraphy in the diagnosis of acute pyelonephritis. Comparative clinical studies have shown renal cortical scintigraphy, using technetium-99m (99mTc)-labeled glucoheptonate or dimercaptosuccinic acid (DMSA), to be significantly more sensitive than either intravenous pyelography or renal sonography in the diagnosis of acute pyelonephritis. However, due to uncertainties about the diagnostic accuracy of the clinical and laboratory parameters used in these studies, true sensitivity of renal cortical scintigraphy was unknown. Therefore, we evaluated the accuracy of [99mTc]DMSA scintigraphy in the diagnosis of experimentally induced acute pyelonephritis in piglets using strict histopathologic criteria as the standard of reference. The sensitivity and specificity of the DMSA scan for the diagnosis of acute pyelonephritis were 91% and 99%, respectively, with an overall 97% agreement between the scintigraphic and histopathologic findings. Based on the results of this experimental study, we used the [99mTc]DMSA scan as the standard of reference for the diagnosis of acute pyelonephritis, and conducted a prospective clinical study of 94 children hospitalized with the diagnosis of acute febrile urinary tract infection (UTI). The aims of this study were (1) to determine the relationship among vesicoureteral reflux, P-fimbriated Escherichia coli, acute pyelonephritis, and renal scarring, and (2) to evaluate the diagnostic reliability of the clinical and laboratory parameters commonly used in the diagnosis of acute pyelonephritis. We documented acute pyelonephritis in 62 (66%) of 94 patients. Vesicoureteral reflux was demonstrated in 29 (31%) of the total group and in only 23 (37%) of 62 patients with acute pyelonephritis. The prevalence of P-fimbriae in the E coli isolates was 64% in the patients with acute pyelonephritis and 78% in those with a normal DMSA scan. Even in patients without reflux, P-fimbriae were found in 71% of isolates from the patients with acute pyelonephritis and in 75% of those with a normal renal scan. Follow-up DMSA scans were obtained in 33 patients with acute pyelonephritis in 38 kidneys. We found complete resolution of the acute inflammatory changes in 58% of the involved kidneys and renal scarring in the remaining 42%, including 40% of the kidneys associated with reflux and 43% of those without reflux.(ABSTRACT TRUNCATED AT 400 WORDS)


Outpatient treatment of the mentally ill chemical abuser: an overview of problems and treatment strategies. Patients who suffer from the effects of mental illness as well as chemical dependency have fared poorly in traditional mental health and substance abuse treatment. Presenting themselves in increasing numbers at both types of settings, they create challenges for clinicians. This article defines the scope of the problem and reviews treatment philosophies for the development of new approaches to care. Social workers can play a leadership role in integrating treatment theory and developing new clinical models in response to the challenges this patient population presents.


Adolescent drug treatment, a family affair: a community day center approach. This paper describes a day care program for treating youth drug abuse. Day care treatment is situated in the middle, between outpatient care and the full-time alternatives such as residential therapeutic communities. Day care is structured to treat youth drug abuse as a family problem and requires behavioral change in all family members. Some social work interventions aimed at effecting family changes are outlined and illustrated. Follow-up research indicates that this approach is a viable one in treating youth drug abuse.


On the hepatotoxicity of 1,1,2,2-tetrachloroethane. Intoxication of male and female mice with a single dose (300 or 600 mg/kg) of 1,1,2,2-tetrachloroethane (TTCE) resulted in significant decreases in cytochrome P-450 (to 58-73% of the control) and NADPH-cytochrome (P-450) c-reductase (to 29-35% of the control) in hepatic microsomes. This was accompanied by an alteration of mixed function monooxygenases stemming from the marked reduction (to 20-64% of the control) of several oxidative activities to selected substrates towards different P-450 isozymes (classes IA1, IA2, IIB1, IIE1 and IIIA). As phase II markers, epoxide hydrolase (approximately 35% loss), UDP-glucuronosyl transferase (approximately 42% loss) and to a lesser extent glutathione S-transferase (approximately 17% loss) were all affected. Also, the activity of delta-aminolevulinic (ALA) synthetase was decreased (approximately 57% of the control). On the contrary, heme oxygenase activity was increased (up to 35%) at the maximal dose tested. The decrease of P-450-function may be explained in terms of an alteration in the rate of heme biosynthesis and degradation, provoking a loss of heme content (approximately 33%) as well as of the direct inactivation of both P-450 and reductase. Because of increasing evidence on the involvement of free radical intermediates in the case of toxicity of haloalkanes, electron spin resonance spectroscopy (ESR) spin-trapping in vivo techniques were used to characterize the possible free radical species involved in the observed liver damage. The results obtained with the spin-trap N-benzylidene-2-methylpropylamine N-oxide (phenyl t-butylnitrone, PBN) provide evidence for the formation and trapping of the CHCl2CHCl free radicals. The detection of conjugated diene signals by means of second-derivative spectrophotometry, have enabled us to show that in vivo lipid peroxidation may be one of the main mechanisms responsible for TTCE hepatotoxicity.


N-methyl-N'-nitro-N-nitrosoguanidine: the effect on migration and cGMP level of neutrophils. N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) causes a concentration-dependent increase of the cGMP level in rabbit peritoneal neutrophils. MNNG has a strong chemokinetic effect on neutrophils. In addition the compound also possesses a moderate chemotactic effect. The potentiating effect of MNNG on neutrophil migration is completely inhibited by pertussis toxin. The results support the view that in neutrophils cGMP is involved in chemokinesis and chemotaxis and that the cGMP-mediated potentiation of migration is controlled by a pertussis toxin-sensitive G-protein.


Secretory activity of equine polymorphonuclear leukocytes: stimulus specificity and priming effects of bacterial lipopolysaccharide. Neutrophil (PMN) contributions to the acute inflammatory process and host defense include generation of bioreactive oxygen metabolites and secretion of granule enzymes. We assessed equine PMN secretion using several PMN stimuli, singly and in combination with bacterial lipopolysaccharide (LPS). LPS avidly associated with equine PMN, as shown by strong PMN labeling with FITC-conjugated LPS. LPS alone (1 or 10 micrograms ml-1) was a weak stimulus for PMN superoxide anion (O2-) generation, but preincubation with LPS followed by phorbol ester (PMA, 10 ng ml-1) significantly augmented (P less than 0.01) secretion of O2- (19.38 nmol O2- per 2 x 10(6) PMN per 5 min) over the amount generated by PMA stimulation alone (13.75 nmol O2-). A qualitatively similar, but smaller O2(-)-generation response occurred when either opsonized zymosan or recombinant human C5a was used as the PMN stimulus. Arachidonic acid (ArA; 50-200 microM) was a potent stimulus, with secreted O2- levels similar to those from PMA-stimulated PMN. Preincubation of PMN with either the formyl peptide, fMLP, or platelet-activating factor before stimulation with ArA did not significantly increase O2- generation over levels obtained using ArA alone. Release of PMN granule enzymes was also quantitated. A small amount of lysozyme secretion resulted when PMN were exposed to LPS alone (8.20% of total cell content), and PMA stimulation caused marked release of PMN lysozyme (44.45%). Non-specific proteolytic activity in PMN supernatants, assessed by cleavage of a collagen-rich substrate, was minimal with LPS as a sole stimulus (5.08%). There was significant proteolytic activity (P less than 0.01) in supernatants from PMA-stimulated PMN (27.21%), and preincubation with LPS followed by PMA stimulation slightly enhanced (P less than 0.05) the release of PMN proteases (34.62%). The activities of beta-glucuronidase, acid phosphatase, and alkaline phosphatase were minimal in PMN supernatants when using LPS and PMA as stimuli. The activity of PMN granule enzymes was found to be sensitive to the presence of normal equine serum, and proteolytic activity was markedly reduced (80.13% reduction) in the presence of 10% pooled serum.


Prevalence of feline immunodeficiency virus and other retroviral infections in sick cats in Italy. Two hundred and seventy-seven sick pet cats living in Italy were tested for antibodies to feline immunodeficiency virus (FIV) and for feline leukemia virus (FeLV) antigen. Overall, 24% of the cats resulted positive for anti-FIV antibody and 18% for FeLV antigen. FIV was isolated from the peripheral mononuclear blood cells of ten out of 15 seropositive cats examined and from one out of eight saliva samples. No FIV isolations were obtained from six serum samples cultured. Feline syncytium forming virus (FeSFV) could be isolated from blood and/or saliva in ten out of 11 FIV seropositive cats examined, in six out of nine FeLV antigen positive cats, in two cats found positive for both infection markers, and in three out of 11 cats negative for both markers. Thus, the probability of isolating FeSFV was enhanced by infection with other exogenous retroviruses.


[Laser surgery and phototherapy of the larynx and laryngopharynx under indirect laryngoscopy]. The authors elaborated the equipment and technique of endolaryngeal laser surgery under indirect laryngoscopy in conditions of local anesthesia as well as phototherapy of the larynx with coherent and noncoherent monochromatic light in the postoperative period. Therapy was conducted and assessment of its efficacy was made in 93 patients with benign tumours, cysts of the larynx and laryngopharynx, cicatricial membranes of the middle regions of the larynx. The efficacy of the given method was assessed on the basis of long-term laryngoscopic studies, stroboscopy and acoustic measurements of the voice. Indications and contraindications to the mentioned therapy have been specified.


[Current methods of detection and localization of vagal chemodectomas]. The modern methods of diagnosis were analysed in 19 patients with chemodectoma of vagal glomus verified surgically and morphologically. The cytological investigation of the tumour punctates was made in 9 patients, ultrasonic introscopy in 2, computer tomography in 13 and arteriography in 17 patients. The informativeness of cytological and ultrasonic studies is low, whereas computer tomography and carotid arteriography are regarded as the method of choice for diagnosis and assessment of vagal chemodectoma prevalence.


Simian virus 40 mutants with amino-acid substitutions near the amino terminus of large T antigen. A series of amino-acid substitution mutants has been made with changes in the region of simian virus 40 large tumor antigen (T antigen) that is shared with the small tumor antigen (t antigen). Both single and multiple amino-acid replacements were obtained using the heteroduplex deletion loop method and sodium bisulfite as the mutagen. The mutants could be divided into five phenotypic classes on the basis of their biological properties: a) mutants whose changes did not affect their ability to propagate on permissive monkey cells, nor to transform nonpermissive rodent cells; b) mutants that were not viable, replicated their DNA to 5% or less of wild type, but were positive for transformation; c) mutants that were not viable, replicated their DNA to 5% or less of wild type, and were defective for transformation; and d) mutants that completely lost all three activities coordinately. In addition, one mutant with changes in this region, 5002, replicated its DNA to about 50% of wild type, had an impaired transformation activity, and produced virions at a level of about 4% that of wild type.


The complete nucleotide sequence of a variant of Coxsackievirus A24, an agent causing acute hemorrhagic conjunctivitis. The complete nucleotide sequence was determined for the cDNAs that represent the RNA genome of the standard strain of a variant of coxsackievirus A24, the EH24/70, one of the agents causing acute hemorrhagic conjunctivitis. The genome is 7461 nucleotide long and is polyadenylated at the 3'-end terminus. Following a 750-nucleotide 5'-noncoding region, there was a long open reading frame of 6642 nucleotides, which serve to encode a viral polyprotein consisting of 2214 amino acids. Comparison of the deduced amino acid sequence of the polyprotein with those of known enteroviruses allowed us to predict the possible cleavage sites. The overall structure and the organization of the RNA genome is typical for an enterovirus. Based on the similarity of the nucleotide sequence of the 5' and 3' noncoding regions, together with the amino-acid sequence of the encoded proteins, EH24/70 appeared to be closely related to polioviruses and coxsackievirus A21.


Evolution of thymidine and thymidylate kinases: the possibility of independent capture of TK genes by different groups of viruses. Phylogenetic analysis of viral and cellular thymidine and thymidylate kinases was performed using computer-assisted methods. Multiple alignments and tentative phylogenetic trees were generated for the two families of these enzymes, which include a) thymidine kinases (TK) of mammals, poxviruses, African swine fever virus, E. coli, and bacteriophage T4; and b) thymidylate kinases (ThyK) of yeast and poxviruses and distantly related herpesvirus proteins with both enzymatic activities. Analysis of the alignment of the TKs of the first family highlighted three strongly conserved segments. Two of these corresponded to the A and B motifs of the purine NTP-binding pattern. The third, C-terminal segment, showing the highest conservation, encompassed a modified Zn finger motif. It is speculated that this motif might be involved in TK oligomerization. Phylogenetic trees constructed by three different methods suggested that cellular TK genes could be captured independently by T4 bacteriophage, African swine fever virus, fowlpox virus, and the other poxviruses. The observed tree topologies appear to contradict the popular virus-host coevolution schemes and to imply that different subdivisions of poxviruses diverged at earlier stages of evolution than their hosts did. It was shown that deoxynucleoside monophosphate kinase of bacteriophage T4 is related to the ThyK family. Phylogenetic analysis suggested that ThyK genes probably have been acquired independently by phage T4, poxviruses, and herpes-viruses.


[Is there in Belgium an increase in resistance to the combination amoxicillin/clavulanic acid of Escherichia coli as reference bacteria?]. The difficulties encountered in measuring the susceptibility of the association amoxicillin/clavulanate can be a cause for disagreements between laboratories. With an inoculum standardized at 10(4) CFU/spot, the resistance level of E. coli approaches 10%. If the variety of current methods is taken into account, the evaluation of a resistance increase can only be an internal one, specific for each laboratory, provided that methods do not change in the course of time.


Large granular lymphocyte proliferative disease: 21 Belgian cases and review of the literature. We report the findings in 21 Belgian patients (12 males and 9 females, median age 61 years) with LGLPD. Symptoms at presentation included infection (n = 9), weight loss (n = 5), asthenia (n = 9), pruritus (n = 2) and arthralgia (n = 7). Four patients were asymptomatic. The main clinical findings were hepatomegaly (n = 5), splenomegaly (n = 8), lymph node enlargement (n = 3) and arthritis (n = 5). All patients had an increased LGL count associated with anemia (n = 12), neutropenia (n = 17), often less than 0.5.10(9)/L (n = 10) and thrombocytopenia (n = 6). Three patterns of lymphocyte surface markers were observed: CD3+CD4-8+ (14 patients), CD3+CD4-8+ (5 patients) and CD3+CD4+8- (1 patient). An abnormal karyotype was found in 2 patients. T-cell receptor gene was rearranged in all cases tested (9/9).


Pulmonary arterial hypertension in sepsis and the adult respiratory distress syndrome. Pulmonary arterial hypertension, defined as a mean pulmonary artery pressure exceeding 20 mmHg has been observed both in experimental animal and human sepsis, even before development of the adult respiratory distress syndrome. In this article we review several mechanisms that have been invoked for the pulmonary arterial hypertension associated with sepsis (and the adult respiratory distress syndrome): obstruction of the pulmonary microcirculation with microthrombi composed of platelets and leukocytes, and active pulmonary vasoconstriction induced by the autonomous nervous system, hypoxia or vasoactive humoral factors ("mediators"). Some of these mediators, in particular serotonin and arachidonic acid metabolites have been the subject of substantial research and therapeutic manipulation. Since pulmonary arterial hypertension imposes an increased afterload to the right ventricle and because right ventricular dysfunction appears to be a major determinant of the outcome of sepsis, the study of the mechanisms involved in pulmonary arterial hypertension may lead to improved management of sepsis and septic shock.


Fever of unknown origin, a literature survey. This review summarizes the different causes of fever of unknown origin reported in the internationally indexed literature from 1961 till 1990. In 1961 Petersdorf published his landmark report that, for the first time, proposed criteria that cases have to meet to be considered as fever of unknown origin. We only retained cases and series that met these criteria. We meticulously compared the reported case series and tried to explain the differences between these series.


Local excision of carcinoma of the rectum: indications. To discuss indications for local excision of adenocarcinoma of the low rectum, two different series of patients were analysed. Series I consisted of 60 patients treated by local excision from 1969 to 1985 in whom local recurrence developed. Series II consisted of 59 patients who underwent resection for non high grade tumors less than or equal to 3.5 cm from 1980 to 1990 in whom lymph node spread was studied. A distinction is made between tumors which are obvious cancers and malignant polyps, and the discussion of indications for local excision is orientated to the former. The results of local excision have been disappointing but a number of compromise selections for local excision have been necessary. Endorectal ultrasound has emerged as the most important method of assessing the depth of invasion of the tumor. Stratifying the depth of the tumor is at present the most important prognostic indicator for lymph node metastasis and local recurrence in non high grade tumors. If the muscle layer is invaded by tumor, local metastasis will occur in 17% of patients. It is likely that only tumors involving superficial layers of muscle are suitable for local excision, but this needs further study. Mucinous carcinomas and the presence of lymphatic invasion are contra-indications to local excision. The shape and size of tumors are not independent prognostic indicators. The techniques available for local excision alter the indications. Salvage operations for recurrence after local excision have proved disappointing.


[Recurrent cutaneous ecchymoses and hypersensitivity to leukocytic stroma]. A 17-year-old woman presented painful recurrent ecchymoses. Identical lesions were specifically induced by injection of autologous leukocytic stroma. No evidence for possible immunological disturbances was found. Therapy with Nivaquine induced a complete and prolonged remission. The differential diagnosis of this rare form of non-thrombocytopenic purpura, the autosensitization to D.N.A. or to leucocytic stroma, is discussed.


Should semi-automatic defibrillators be used by emergency medical technicians in Belgium? The Belgian Cerebral Resuscitation Study Group. Early external defibrillation is the single most effective intervention in patients with out-of-hospital cardiac arrest. Literature data indicate that instructing emergency medical technicians (EMTs) to use defibrillators is beneficial, provided the local emergency medical system is well organized. We tried to estimate the potential benefit of early defibrillation in some centres in Belgium by retrospectively analyzing the data from the Belgian Cardio-Pulmonary-Cerebral Resuscitation Registry collected between 1983 and 1987 in Belgian centres with a Mobile Intensive Care Unit (MICU). The data show that 2310 out of 3371 patients (69%) were first attended by the EMTs; on subsequent arrival of the MICU-teams, 584 of these 2310 patients i.e. 17% of the whole study population, presented with ventricular fibrillation. Analysis of estimated time factors in these 2310 patients revealed that the median time interval between collapse and start of resuscitation by EMTs was 8 min; the median time interval between collapse and start of MICU-resuscitation attempts was 16 min. The duration of EMT-resuscitation before MICU-arrival was probably more than 5 min and 10 min in 58% and 23% of the cases respectively. It is concluded that EMTs can be expected to reach a substantial number of ventricular fibrillation victims within a few minutes after the collapse and many minutes before arrival of the MICU. Therefore, training of EMTs in the use of semi-automatic defibrillators seems worthwhile in MICU-served regions in Belgium.


An African patient with AIDS and linitis plastica. This is a case report about an African patient with AIDS who was diagnosed with a linitis plastica of the stomach. The evolution of this linitis plastica does not differ in any aspect from that in HIV-negative patients. The question remains unanswered whether there is a link between the HIV infection and the development of linitis plastica in this patient.


Talocrural arthrodesis with absorbable screws, 12 cases followed for 1 year. In 11 patients, 12 arthrodeses of the ankle joint were performed by using absorbable self-reinforced poly-l-lactide (SR-PLLA) or polyglycolide (SR-PGA) screws. 8 patients had posttraumatic arthrosis, 3 rheumatoid arthritis, and 1 rigid flexion contracture of the ankle due to neuropathy. The average follow-up time was 14 (7-22) months. Solid fusion was achieved in 11 of 12 cases in 9(6-16) weeks.


Foreign-body reactions to polyglycolide screws. Observations in 24/216 malleolar fracture cases. Out of 216 patients with displaced malleolar fractures operated on using absorbable polyglycolide screws, 24 developed a transient local nonbacterial inflammatory reaction on an average 3 months after the operation. Upon histopathologic examination, these tissue responses were found to be nonspecific foreign-body reactions. Neither the age of the patient nor the number of screws used in the fixation affected the incidence of the reactions. The first-generation screws that were colored with an aromatic quinone dye showed a higher incidence, 19 reactions among 105 patients, than the new noncolored implants, 5 among 111 patients (P less than 0.01). No deleterious effect of these tissue responses on the union of the fractures could be detected, but the possible long-term consequences of this complication are so far unknown.


[Neural crest derived retroperitoneal tumors. General review]. Presentation of a series of 14 cases of neural crest derived tumours located in the retroperitoneal space in adult patients (five pheochromocytoma, six paraganglioma, two ganglioneuroma, and one neuroblastoma), and review and update of the diagnostic and therapeutic aspects. All pheochromocytoma cases presented high BP and the classic triad of sudation, tachycardia and headaches, as well as high levels of blood and urine catecholamines and/or their metabolites. CAT, ultrasound scanning and 123MIBG were the main diagnostic techniques used. All four paraganglioma were functioning and generally located surrounding both kidneys (one case was paired). No malignancy was found in any of the 11 tumours while controls remain with normal BP and normal levels of urine catecholamine metabolites. None of the two ganglioneuromas showed specific signs and symptoms but were diagnosed accidentally. The one neuroblastoma was juxtavesical showing a highly unfavourable evolution in spite of radical surgery, radiotherapy and multiple chemotherapy and the patient died within 16 months with local recurrence and haematogenous dissemination to bones and lungs.


Assessment of a new modified soft jelly capsule containing nonoxynol as spermicide contraceptive. The mean rupture time, after its vaginal insertion, of a new modified soft jelly capsule containing nonoxynol-9 (DF-486) was investigated in 40 women. The subjects were randomly allocated to 8 study groups. The capsules remained in the vagina from 2-13 minutes. Vaginal infection, vaginal dryness, and multiparity, were recorded. Capsule rupture was not observed at minute 2; 20% of capsules that remained in the vagina 3 minutes suffered rupture, as did 80% of capsules that remained 4, 5 and 7 minutes, and 100% of those remaining 9 minutes or more. The mean rupture time of the studied capsules was 8.2 minutes with 95% confidence limits of 6.2 and 8.8 minutes. At minutes 2-7, vaginal infection, dryness and tone diminution probably accounted for lack of rupture; after minute 7, these factors did not influence capsule rupture.


Rupture of hepatocellular carcinoma: predictive value of CT findings. To assess the value of CT in predicting spontaneous rupture of hepatocellular carcinoma, we reviewed CT scans obtained within 3 months before the rupture of hepatocellular carcinoma in 23 patients (rupture group) and within 3 months before death of any cause other than rupture of hepatocellular carcinoma in 20 patients with tumor contacting or protruding out of the liver margins (nonrupture group). All the carcinomas in the rupture group were located in the periphery of the liver. They protruded out of the liver margins in 18 cases and contacted the liver margins without protrusion in five cases. For the rupture and nonrupture groups, respectively, mean numbers of involved liver segments were 4.2 +/- 2.3 and 2.3 +/- 1.3 (p less than .01); mean maximal tumor areas were 102.0 +/- 57.0 cm2 and 57.7 +/- 50.9 cm2 (p less than .05); frequencies of tumor protrusion was 78% and 50% (NS); mean maximal lengths of protruded margins of the tumor were 188.1 +/- 81.4 mm and 77.2 +/- 50.3 mm (p less than .01); frequencies of extrahepatic invasion of the tumor were 44% and 20% (NS); and frequencies of ascites were 78% and 50% (NS). No significant differences in age or sex of the patients and clinical stage of the cancer were evident between the two groups. Multiple regression analysis (p less than .005, r2 = .428) indicated that, of the CT findings, maximal length of protrusion correlated best (p less than .05) with subsequent rupture. We conclude that increased tumor size and extent of extrahepatic protrusion are associated with an increased risk for rupture of hepatocellular carcinoma.


Silica exposure in hand grinding steel castings. Exposure to silica dust was studied in the grinding of castings in a steel foundry that used conventional personal sampling methods and new real-time sampling techniques developed for the identification of high-exposure tasks and tools. Approximately one-third of the personal samples exceeded the National Institute for Occupational Safety and Health recommended exposure limit for crystalline silica, a fraction similar to that identified in other studies of casting cleaning. Of five tools used to clean the castings, the tools with the largest wheels, a 6-in. grinder and a 4-in. cutoff wheel, were shown to be the major sources of dust exposure. Existing dust control consisted of the use of downdraft grinding benches. The size of the casting precluded working at a distance close enough to the grates of the downdraft benches for efficient capture of the grinding dust. In addition, measurements of air recirculated from the downdraft benches indicated that less than one-half of the respirable particles were removed from the contaminated airstream. Previous studies have shown that silica exposures in the cleaning of castings can be reduced or eliminated through the use of mold coatings, which minimize sand burn-in on the casting surface; by application of high-velocity, low-volume exhaust hoods; and by the use of a nonsilica molding aggregate such as olivine. This study concluded that all these methods would be appropriate control options.


Performance of laboratories measuring silica in the Proficiency Analytical Testing program. A statistical study was performed on the results reported by laboratories analyzing silica samples in the first 101 rounds of the Proficiency Analytical Testing (PAT) program. Five laboratories participated in the first round of the PAT program in 1972, and participation grew to 130 laboratories before falling to 105 in Round 101. The laboratories use all three of the major methods of analysis: colorimetry, x-ray diffractometry, and infrared spectroscopy. The objectives of the study were to determine bias between methods, the variability associated with the methods, and any changes in bias or variability caused by a number of factors. The colorimetric method has consistently given the lowest results, particularly at higher loadings. X-ray diffractometry results were biased higher than infrared spectroscopy results during one period but not in the following period. Between the two periods, the procedures and materials used to prepare PAT samples changed in a number of ways, but the switch to quartz dust with a smaller particle size is a likely explanation for the bias difference. Generally, silica analyses have improved in precision over time, and this improvement has taken place for all three of the methods. The colorimetric method has shown the poorest precision of the three methods, but, unlike the differences in bias, the differences in precision have diminished considerably over time. Precision estimates from other studies were compared to those from this study to learn more about sources of variability. The largest source of variability, the differences between laboratories, was large even when laboratories used the same method, as they did in a collaborative study of silica methods.


Occupational exposures in California wildland fire fighting. Industrial hygiene measurement of exposures to wildland fire fighters was conducted in northern California during three consecutive fire seasons (1986-1989) in conjunction with three separate health effects studies. Chemicals that were monitored included carbon monoxide, total and respirable particulates, polyaromatic hydrocarbons (PAHs), crystalline silica, aldehydes, and benzene. Measurements were taken at both wildland fires and prescribed (planned) burns. A variety of collection methods were employed--colorimetric detector tubes and a CO monitor were used for direct-reading area measurements; colorimetric diffusion tubes, filter cassettes, sorbent tubes, and passive vapor monitors were used for determining personal time-weighted average exposures. A new screening method (National Institute for Occupational Safety and Health Method 2539) was used to identify the presence of specific aldehydes. Results show that wildland fire fighters may at times be exposed to concentrations of carbon monoxide, total or respirable particulates, or silica at levels near or higher than recommended occupational exposure limits, although group means were generally well below the limits. Time-weighted average formaldehyde levels, measured in a few instances above 0.37 mg/m3 (0.3 ppm), indicate a potential for formaldehyde-induced eye or respiratory irritation under these conditions. Certain characteristics of the work such as high altitude, temperature, and breathing rate; extended work shifts; and additional off-shift exposures suggest that adjustment of 8-hr exposure limits may be necessary to provide adequate protection. In part, because of the rigors of performing industrial hygiene measurements under fire fighting conditions, data are limited and could not be considered representative of the full range of exposures fire fighters may encounter.(ABSTRACT TRUNCATED AT 250 WORDS)


Phase II study of combination therapy with high-dose cisplatin, etoposide, and mitomycin in patients with advanced non-small-cell lung cancer. Forty-six patients with metastatic non-small-cell lung cancer (NSCLC) were treated with a combination of high-dose cisplatin, etoposide, and mitomycin. Thirty-four patients (74%) had a performance status of 1, and 39 patients (85%) had adenocarcinoma. Of the 42 patients evaluable for response and toxicity, four achieved a partial response (10%); no patient achieved a complete response. Seven patients who had received prior chemotherapy showed no major response. The median survival of all 42 patients was 23 weeks. Myelosuppression was the major dose-limiting toxicity for this regimen, and 12 of 46 patients (26%) developed neutropenic fever requiring hospitalization and parenteral antibiotics. Of the 12 patients with severe neutropenic fever, one patient died because of toxicity. Nonhematologic toxicities, including azotemia, peripheral neuropathy, nausea, vomiting, and hearing loss were transient and modest. We conclude that high-dose cisplatin combined with etoposide and mitomycin is a relatively toxic regimen with a low response rate. Further evaluation of the combination as given in this trial is not warranted.


Cytomegalovirus pseudotumor presenting as bowel obstruction in a patient with acquired immunodeficiency syndrome. Although cytomegalovirus (CMV) can be fatal to patients with the acquired immunodeficiency syndrome (AIDS), it usually causes few, if any, symptoms. The virus has an affinity for the alimentary tract, especially the ileum and right colon. CMV infections of the gut are often erosive, resulting in enterocolitis, hemorrhage, or intestinal perforation. Inflammatory mass formation is rare. Kaposi's sarcoma and lymphoma are established causes of bowel obstruction in patients with AIDS. This report describes a case of ileocecal obstruction due to a discrete CMV-induced pseudotumor in a patient with AIDS.


Regulation of agonist-evoked [Ca2+]i oscillation by intracellular Ca2+ and Ba2+ in AR42J cells. Measurements of intracellular Ca2+ ([Ca2+]i) and intracellular Ba2+ ([Ba2+]i) in single AR42J cells were used to evaluate the effect of [Ca2+]i and [Ba2+]i on agonist-evoked [Ca2+]i oscillations. Variations in [Ca2+]i and [Ba2+]i were imposed by gradual activation of entry through voltage-activated Ca2+ channels (VACC) present in the plasma membrane of these cells. Activation of high K+ was followed by partial inactivation of the channels and stabilization of [Ca2+]i at a new steady-state level depending on the extent of depolarization. Activation by BAY K 8644 was followed by complete inactivation and return of [Ca2+]i to resting levels. Ba2+ activated the channels and entered the cells but could not be removed from the cytosol by cellular Ca2+ pumps. The use of channel blockers and the ability to increase [Ca2+]i and [Ba2+]i by channel activation during [Ca2+]i oscillations showed that VACC do not contribute to or are activated during agonist-stimulated Ca2+ oscillation in this cell type. Graded activation of VACC showed that an increase in [Ca2+]i between the spikes to below 200 nM increased the frequency of the oscillation. Further increase in [Ca2+]i caused gradual reduction in the frequency. At [Ca2+]i above 500 nM, [Ca2+]i oscillations were inhibited. The inhibitory but not the stimulatory effects of [Ca2+]i on the oscillations can be mimicked by [Ba2+]i. These observations suggest that [Ca2+]i levels between the spikes play an important role in regulating the oscillations.


Atrial natriuretic peptide receptor subtypes in rat neuronal and astrocyte glial cultures. We have compared the levels and subtypes of atrial natriuretic peptide (ANP) receptors in astrocyte glial and neuronal cultures prepared from the hypothalamus and brain stem of 1-day-old rats. Astrocyte glial cultures contain approximately twice the number of ANP receptors, as measured by 125I-ANP specific binding, compared with neuronal cultures. Rat ANP-(99-126), rat brain natriuretic peptide (BNP32), C-type natriuretic peptide (CNP-22), atriopeptin I, and [des-Gln18,Ser19,Gly20,Leu21, Gly22]atrial natriuretic factor-(4-23)-NH2[C-ANF-(4-23)] all competed strongly for 125I-ANP binding in both culture types, with inhibitory constant values ranging from 0.47 to 8.07 nM. The presence of ANP-C receptors (clearance type) in both cell types is indicated from the strong competition of 125I-ANP specific binding by C-ANF-(4-23). The potency profiles for stimulation of guanosine 3',5'-cyclic monophosphate levels by these peptides were ANP = BNP much greater than CNP-22 greater than atriopeptin I in astrocyte glia and CNP-22 much greater than BNP32 greater than ANP greater than atriopeptin I in neuronal cultures. These results indicate that both types of culture contain guanylate cyclase-coupled ANP receptors, with astrocytes containing predominantly the ANP-A subtype and neurons predominantly the ANP-B subtype.


Altered coupling of alpha 1-adrenergic receptor-G protein in rat parotid during aging. A possible role for altered signal transduction mechanisms in impaired alpha 1-adrenergic-stimulated secretory function during aging was investigated in parotid cells prepared from adult (6 mo) and old (24 mo) rats. Compared with adults, epinephrine-stimulated 45Ca2+ efflux and inositol 1,4,5-trisphosphate [Ins(1,4,5)P3] production were reduced 31 and 36% in cells of old rats, respectively. There was a highly significant correlation between 45Ca2+ efflux and Ins(1,4,5)P3 production. In saponin-permeabilized cells, no significant differences in Ins(1,4,5)P3-stimulated 45Ca2+ efflux in adult and old preparations were observed. When G proteins were stimulated by guanosine 5'-O-(3-thiotriphosphate) or NaF, no age differences in Ins(1,4,5)P3 production were detected. Stimulation of phosphoinositide-specific phospholipase C (PLC) by CaCl2 in adult and old cells was also comparable. Moreover, no differences in immunolabeled common alpha (GTP binding site), Gi alpha, PLC-gamma, or PLC-delta could be detected in either cytosol or membranes of adult and old preparations. In the absence of 5'-guanylylimidodiphosphate [Gpp(NH)p], no age-related changes in epinephrine competition for [3H]prazosin binding sites were observed. Approximately 30% of the agonist binding sites existed in a high-affinity form at both ages. Gpp(NH)p caused large rightward shifts of epinephrine displacement curves in adult membranes (converting all binding sites to the low-affinity form), but not old. Moreover, epinephrine was much more effective in stimulating G protein low-Km GTPase in parotid membranes from adult than old rats. These data suggest that age-related impairments in alpha 1-adrenergic responsiveness are mediated, at least in part, by the functional alterations in the coupling of G proteins with alpha 1-adrenergic receptors.


Signal transduction by the erythropoietin receptor: evidence for the activation of phospholipases A2 and C. Erythropoietin (Ep) is the peptide growth factor whose actions on the erythroid progenitor cell induce terminal differentiation. However, the intracellular signaling system that is activated by Ep is poorly understood. Our previous studies have implicated the lipoxygenase metabolites of arachidonic acid in the actions of Ep. In this study, we report an early (30 s to 5 min) increase in levels of two lipoxygenase metabolites: leukotriene B4 (LTB4; 3- to 5-fold) and 12-hydroxyeicosatetraenoic acid (12-HETE; 2-fold). These responses were blocked by an antibody to Ep, by lipoxygenase inhibitors, or by 1,6-di[O-(carbamoyl)cyclohexanone oxime]hexane (RHC80267), an inhibitor of diacylglycerol (DAG) lipase. RHC 80267 also significantly inhibited Ep-mediated proliferation. Ep induced the release of [3H]arachidonic acid from cellular phospholipids at 5 min and also increased DAG accumulation at 1 min with a maximum increase of 68.2% over control seen at 30 min. No increase in levels of inositol trisphosphate or phosphatidic acid was observed in response to Ep. Taken together, these data suggest that the signal transduction pathway of the Ep receptor includes the activation of phospholipases A2 and C, resulting in the liberation of DAG and arachidonate and the subsequent formation of LTB4 and 12-HETE.


Phorbol ester inhibits erythropoietin production in human hepatoma cells (Hep G2). Using the human hepatoma cell line Hep G2, we have studied a possible role of protein kinase C (PKC) activity for regulation of erythropoietin (EPO) production. During a 72-h incubation, EPO production by the cells was stimulated sevenfold by exposure to low oxygen tension (1%) and threefold by exposure to cobaltous chloride (100 microM). The phorbol ester phorbol 12-myristate-13 acetate (PMA) led to a concentration-dependent inhibition of basal and stimulated EPO formation (ED50 10 nM). This decrease of EPO production, which was apparent already after 1 h of incubation with PMA, reached its maximal effect after 24 h and held on for 72 h. It was paralleled by an inhibition of the increase of EPO mRNA levels in response to stimulation. A 24-h preincubation of the cells with PMA (100 nM) virtually blunted the effect of hypoxia on EPO formation. Recovery of EPO synthesis after removal of PMA took 48-72 h. The effect of PMA on EPO production was mimicked by phorbol 12,13-dibutyrate (ED50 1 microM) but not by 4 alpha-phorbol 12,13-didecanoate. The synthetic diacylglycerol analogues oleolyl-acetylglycerol and dioctanoylglycerol (2-200 microM) also had no effect on either basal or stimulated EPO production. Treatment with PMA caused a translocation of the alpha-isoenzyme of PKC from the cytosol to the membrane after 1 h and a disappearance of the membrane-bound form after 24 h of incubation. Staurosporine and 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine, two structurally different inhibitors of PKC activity, inhibited basal and stimulated EPO production with ED50 values of 9 nM and 50 microM, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)


Activation of protein kinase C reduces L-type calcium channel activity of GH3 pituitary cells. These studies describe the effect of protein kinase C (PKC) activation on the activity of voltage-sensitive L-type Ca2+ channels of GH3 pituitary cells. The rate of 45Ca2+ uptake was stimulated greater than 25-fold by depolarization in the presence of BAY K 8644; the phorbol ester 12-O-tetradecanoylphorbol 13-acetate (TPA) reduced this response by 70% in a concentration-dependent fashion. Phorbol 12,13-dibutyrate (PDBu) inhibited depolarization-induced 45Ca2+ uptake within 1 min and caused a nearly maximal reduction after 1 h; its effects were rapidly reversible. TPA decreased the high K(+)-stimulated increase in intracellular free calcium ion concentration ([Ca2+]i) from 8.5- to 3.2-fold by 5 min and to 2.0-fold after 18 h without altering the peak [Ca2+]i response to the peptide hormone TRH. Ca2+ channel current, measured directly using the whole cell configuration of the patch-clamp technique, declined an average of 6.4% over 5 min for control cells and 28.9% when TPA was added to the bathing medium for 5 min. Treatment with 100 nM TPA for 24 h dramatically reduced peak current without shifting the peak of the current-voltage relationship. The mean peak Ca2+ channel current was reduced from 423 to 128 pA, although a few cells seemed completely resistant. To determine whether the effects of phorbol esters were due to the activation of PKC we tested the potency of several drugs to inhibit L-channel activity and to shift the affinity of the epidermal growth factor (EGF) receptor, an established PKC response.(ABSTRACT TRUNCATED AT 250 WORDS)


Coupling and connexin 43 expression in microvascular and large vessel endothelial cells. Endothelial cells of the microvasculature differ both structurally and functionally from endothelial cells of larger vessels. To assess whether these cells also differ in terms of direct cell-to-cell communication, we compared gap junction-mediated intercellular coupling and connexin (Cx) expression in monolayer cultures of bovine microvascular and large vessel (aortic and pulmonary artery) endothelial cells. In confluent monolayers, junctional communication (as assessed by transfer of Lucifer Yellow) was greater between large vessel than between microvascular endothelial cells. Basal levels of connexin 43 (Cx43) and Cx43 mRNA were also greater in large vessel than in microvascular endothelial cells. When monolayers of microvascular endothelial cells were mechanically wounded, junctional communication was increased between migrating cells at the wound edge. In contrast, coupling between large vessel endothelial cells was not increased after wounding. The wound-induced increase in coupling between microvascular endothelial cells was accompanied by an increase in Cx43 and Cx43 mRNA. In contrast, Cx43 expression was unaltered after wounding monolayers of large vessel endothelial cells. These studies revealed differences in basal and wound-induced levels of coupling and Cx43 expression in microvascular and large vessel endothelial cells in vitro, raising the possibility that the role of coupling in endothelial cell function may be different in these different cell types.


Alternate pathways for chloride conductance activation in normal and cystic fibrosis airway epithelial cells. Using whole cell patch-clamp and perforated patch recording techniques on human cystic fibrosis (CF) and non-CF airway epithelial cells, we sought to determine whether a single Cl- conductance (GCl) could be modulated via different regulatory pathways or whether multiple conductances could be identified. Cl- current in both CF and non-CF cells was activated by cellular swelling as well as by an elevation in intracellular calcium ([Ca2+]i). While the adenosine 3',5'-cyclic monophosphate (cAMP)-activated GCl was absent in CF cells, its activation in non-CF cells was only observed in the perforated patch configuration at lower temperatures (24 degrees C) or infrequently in the whole cell configuration at elevated temperatures (33 degrees C). Currents activated by all three regulatory pathways were sensitive to the Cl- channel blocker 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS). Further increases in current activation could be produced by cellular swelling after maximal Ca2+ or cAMP-induced current activation. Intracellular application of a peptide inhibitor of Ca(2+)-calmodulin-dependent protein kinase selectively blocked the Ca(2+)-dependent current activation while leaving the swelling-induced current increase intact. These results are consistent with the presence of multiple anion conductances in both CF and non-CF airway cells. The heterogeneity of the responses to the three regulatory stimuli, however, prevented the correlation of a specific anion conductance with a separate modulatory pathway based on characteristic voltage-dependent kinetics and conductance.


Appearance of alpha 1-adrenergic receptors in soleus muscles from SHR. The depressed functional capabilities of spontaneously hypertensive rat (SHR) muscles, reported previously (Exp. Neurol. 95: 249-264, 1987), may reflect a decrease in muscle responsiveness to catecholamines occurring as a consequence of exposure to the elevated level of plasma catecholamines in SHR. Responsiveness to applied catecholamines was determined in SHR and Wistar-Kyoto rat (WKY) soleus by measuring muscle resting membrane potentials (RMP) in vitro. Epinephrine (10(-6) M) produced a similar membrane hyperpolarization in SHR and WKY fibers. Pretreatment with the beta-antagonist propranolol completely blocked the epinephrine-induced hyperpolarization in WKY, but not in SHR. SHR soleii from both young and old rats contained a population of alpha 1-adrenergic receptors also associated with membrane hyperpolarization. The alpha-receptors appeared to be associated with a ligand-gated Ca(2+)-influx pathway, since the alpha-agonist-induced membrane hyperpolarization required the presence of Ca2+ in the extracellular medium. The alpha-induced hyperpolarization was also blocked by apamin, a derivative of bee venom which blocks a Ca(2+)-activated K(+)-efflux pathway in a variety of tissues. The possible role of these novel alpha-receptors in skeletal muscle function, and their relationship to the development of hypertension, is uncertain.


cGMP-dependent protein kinase regulation of a chloride channel in T84 cells. Chloride channels at the apical membrane of intestinal epithelial cells are involved in the excessive fluid secretion in diarrhea and diminished secretion in cystic fibrosis (CF). Diarrhea induced by heat-stable toxin from Escherichia coli is associated with elevated guanosine 3',5'-cyclic monophosphate (cGMP) in intestinal epithelial cells, but it is unknown whether chloride secretion is regulated by cGMP directly or via cGMP-dependent protein kinase (PKG). Single-channel recordings (inside-out excised patches) from the apical membrane of T84 cells reveal a 10-pS chloride channel with a linear current-voltage relationship, which is opened when an endogenous membrane-bound PKG is activated with ATP (1 mM) and cGMP (100 microM). Soluble PKG (200 nM) isolated from bovine lung, added to the intracellular face of patches, also opens this channel. No activation occurs with Ringer solution alone or only ATP or cGMP. Addition of nonhydrolyzable forms of ATP (AMP-PNP, 1 mM) or a combination of ATP, cGMP, plus H-8 (5 microM), an inhibitor of PKG, also does not stimulate the channel. The catalytic subunit of adenosine 3',5'-cyclic mono-phosphate-dependent protein kinase (PKA, 200 nM, with 1 mM ATP) activates a channel with similar characteristics. The 10 pS channel has a PNa/PCl ratio of 0.06, an anion selectivity of Br- (1.2) greater than Cl- (1.0) greater than I- (0.8) greater than F- (0.4), and a low affinity for the chloride channel blockers, 4,4-dinitrostilbene-2,2-disulfonic acid and 5-nitro-2-(3-phenylpropylamino)benzoic acid.(ABSTRACT TRUNCATED AT 250 WORDS)


Altered renal dopamine receptors during development of cardiac hypertrophy. The characteristics of dopamine receptors were studied in heart and kidney using the radiolabeled receptor assay of [3H]spiperone during the development of cardiac hypertrophy. Male Sprague-Dawley rats (175-200 g) underwent abdominal aortic constriction above the renal arteries and were studied 3, 14, and 28 days thereafter. Sham-operated animals without aortic constriction were used as control. Although the ratio of left ventricular weight to total body weight was significantly increased 14 and 28 days after aortic constriction in animals, [3H]spiperone binding in left ventricular membrane was increased as early as 3 days after aortic constriction. At 14 days, the binding was still elevated and, by 28 days, it returned to control values. In contrast, membranes obtained from kidney cortex showed an elevation of [3H]spiperone binding only at 28 days after aortic constriction; at 3 days the binding values were decreased. A reciprocal correlation was found between the number of dopamine receptors and the activity of Na(+)-K(+)-ATPase at 28 days of aortic constriction; the enzyme activity, as measured by the release of 32Pi from [gamma-32P]ATP, was decreased in kidney cortex. Autoradiographic data also showed an increased number of dopamine receptors in kidney at 28 days after abdominal aortic constriction. These results suggest that the dopamine receptor is increased very early in heart in response to pressure overload as a result of a compensatory response to maintain an optimal left ventricular output. Kidney dopamine receptors are triggered at a later stage possibly to maintain fluid homeostasis secondary to the cardiac hypertrophic process.


Tissue specificity of renin promoter activity and regulation in mice. Certain mouse strains (e.g., DBA/2) contain two renin genes (termed Ren-1 and Ren-2) and express higher renin levels in nonkidney tissues than strains with a single renin gene. The 5'-flanking regions of the Ren-1 and Ren-2 genes contain several TATA boxes preceding putative transcriptional start sites. These initiators are termed P1a, P1, P2 (from 5' to 3'), and their function (with the exception of P2) is largely unknown. In this study, we mapped the renin transcriptional start sites in renal and extrarenal tissues [adrenal, brain, testis, heart, and submandibular gland (SMG)] and examined the effect of adenosine 3',5'-cyclic monophosphate (cAMP) on tissue specific promoter usage. Our results showed that, in the unstimulated state, P2 (the predicted initiator) is active in all DBA/2 mouse tissues. Additional transcriptional start sites were detected in the adrenal and testis (originated by P1a and P2) and the SMG (originated by P1a, P1, and P2). The administration of 8-bromoadenosine 3',5'-cyclic monophosphate led to selective stimulation of P1a in the adrenal but did not affect the selective usage of initiation sites in other organs. A locus-specific ddNTP primer extension assay was used to verify which renin gene is induced by cAMP. Results indicated that both Ren-1 and Ren-2 responded to cAMP treatment in identical fashion. Taken together, these data indicate that more than one form of renin transcript is present in several mouse tissues. There is tissue specificity in promoter usage in the unstimulated state and in response to cAMP.


Peripheral and central angiotensin II regulates expression of genes of the renin-angiotensin system. We investigated whether angiotensin (ANG) II has the potential to regulate expression of genes of the renin-angiotensin system (RAS) in peripheral and central tissues. ANG II (0.1 or 6.0 nmol/h) was infused by osmotic minipump into male Sprague-Dawley rats (225-250 g) for 5 days, either intravenously or intracerebroventricularly. We measured angiotensinogen mRNA in liver, adrenal glands, and brain (hypothalamus and lower brain stem), renin mRNA in the kidney, and angiotensin-converting enzyme (ACE) mRNA in the lung and testis by Northern blot analysis. We demonstrated that plasma ANG II increases the levels of liver angiotensinogen mRNA, decreases kidney renin mRNA, and decreases lung ACE mRNA. Intracerebroventricular administration of ANG II resulted in a different pattern of responses of the peripheral RAS components. Liver angiotensinogen mRNA was increased, and kidney renin mRNA was decreased by both doses of ANG II, whereas lung ACE mRNA remained unresponsive at either dose. Centrally mediated influences of ANG II are most likely indirect since plasma ANG II concentration was not changed. This study has revealed that ANG II has profound diverse effects that influence the regulation of its formation. Further, results indicate that genes of the RAS responded to exogenous ANG II in both tissue- and route-specific ways.


Mechanism of regulation of calcium-pumping activity in chick intestine. The role of the calcium pump in the stimulation of intestinal calcium transport activity by 1 alpha,25-dihydroxyvitamin D3 [1 alpha,25(OH)2D3] was examined in chicks. The in situ intestinal absorption of calcium increased approximately threefold in the duodenum, jejunum, and ileum 6 h after a single injection of 625 ng of 1 alpha,25(OH)2D3 into vitamin D-deficient chicks. The same treatment also increased approximately twofold the rate of ATP-dependent calcium uptake by the basolateral membrane vesicles (BL) isolated from those three sites. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that a Mg(2+)-dependent calcium-stimulated phosphorylated intermediate with an apparent molecular mass of 105 kDa appeared in the BL. The 1 alpha,25(OH)2D3 treatment gave no change in the levels of the intermediate. Pretreatment of the BL with alkaline phosphatase decreased the calcium uptake by the BL isolated from 1 alpha,25(OH)2D3-treated chicks, but it had little effect on the uptake by the BL from vitamin D-deficient chicks. These results suggest that at an early stage of the 1 alpha,25(OH)2D3-induced intestinal calcium transport process, the vitamin regulates the calcium-pumping activity of chick intestinal BL by phosphorylation and dephosphorylation but not by a stoichiometric change in the pump.


Indomethacin-induced leukocyte adhesion in mesenteric venules: role of lipoxygenase products. Although the pathogenetic mechanisms underlying indomethacin-induced mucosal injury remain undefined, the results from recent studies suggest that leukocyte adherence in gastric microvessels may be an important component of this injury process. The objective of this study was to determine whether clinically relevant plasma concentrations of indomethacin promote leukocyte-endothelial cell adhesive interactions in postcapillary venules. Erythrocyte velocity, vessel diameter, leukocyte rolling velocity, and the number of adherent (stationary for greater than or equal to 30 s) and emigrated leukocytes were measured in rat mesenteric venules. Repeat measurements of all parameters were obtained within 20 min after addition of either 2.5 or 25 micrograms/ml indomethacin to the mesenteric superfusate. In some experiments, rats were pretreated with either a leukotriene (LT) synthesis inhibitor (L 663,536), an LTD4 (MK-571) or LTB4 (SC 41930) receptor antagonist, misoprostol, or prostacyclin (PGI2). Indomethacin alone increased the number of adherent leukocytes, reduced both leukocyte rolling velocity and venular shear rate, but did not promote leukocyte emigration. L 663,536 and SC 41930 prevented all of the adhesive and hemodynamic alterations induced by indomethacin; misoprostol and PGI2, but not MK-571, exerted similar beneficial effects. These results indicate that indomethacin promotes leukocyte adherence in postcapillary venules through an LTB4-dependent mechanism.


Regulation of gastrin alpha-amidation in the developing rat stomach. Because the gastrin molecule must be alpha-amidated to have maximum biological activity, rat pups from 1 to 6 wk of age were treated with dexamethasone (2 mg.kg-1.day-1) for 3 or 7 days, diethyldithiocarbamate (DDC; 400 mg.kg-1.day-1 x 3 days), dexamethasone and DDC, pentagastrin (750 micrograms.kg-1.day-1), or bombesin (40 micrograms.kg-1.day-1) for 3 days to determine the effects of these agents on alpha-amidation and gastrin and glycine extended gastrin (G-Gly) concentration in the stomach. Three day treatment with dexamethasone increased gastrin concentration by increasing amidation in pups before 5 wk of age and thereafter by enhancing preprogastrin synthesis or processing. Seven day dexamethasone treatment had no substantial effect on amidation. DDC universally inhibited amidation and affected a sustained increase in gastrin plus G-Gly concentration after the third week of life. Dexamethasone did not reverse the effects of DDC. Pentagastrin increased amidation in 1-, 3-, and 6-wk old rat pups but had no consistent effect on peptide concentration. Bombesin increased the sum of gastrin and G-Gly concentration in all but 1- and 5-wk old pups but had variable effects on alpha-amidation. We conclude that alterations in gastrin alpha-amidation have age-specific effects on tissue gastrin and G-Gly concentration and speculate that changes in tissue gastrin and G-Gly stores available for release might ultimately affect parietal cell and G-cell function during development.


The lungs and vitamin A.

The lungs and vitamin A. Evidence is reviewed supporting the view that vitamin A (retinol) and its metabolite, retinoic acid, called natural retinoids, are major factors involved in differentiation and in maturation of the lungs. This conclusion is based on morphological observation that lack of this dietary micronutrient causes keratinizing squamous metaplasia of the bronchopulmonary tree that can be reversed by refeeding the animal with retinol. In addition to these observations suggesting an indirect participation of retinol and/or retinoic acid in the differentiation of this organ, more direct evidence is presented that this vitamin is involved in pulmonary gene expression. Adult as well as fetal lungs accumulate retinyl esters, the storage form of vitamin A, contain specific retinol- and retinoic acid-binding proteins and, more importantly, express several isoforms of nuclear retinoic acid receptors. These proteins are involved in activation and repression of specific genes regulated by retinoic acid. That retinol and/or retinoic acid may be involved in lung maturation is suggested by experimental results showing depletion of lung retinyl esters at birth, by significant alterations in the levels of the cellular retinoic acid-binding protein during lung maturation and, more importantly, by reduction in the morbidity of prematurely born human neonates who are given vitamin A because they are susceptible to bronchopulmonary dysplasia.


Impairment of sodium-coupled uptakes by hydrogen peroxide in alveolar type II cells: protective effect of d-alpha-tocopherol. Hydrogen peroxide (H2O2) is likely to play an important role in oxidant alveolar epithelium injury. We investigated the effect of H2O2 on uptake of phosphate, alanine in cultured rat alveolar type II cells. H2O2 induced inhibition of Na-dependent component of phosphate and alanine uptakes in time- and concentration-dependent manner. Twenty minutes exposure to 2.5 mM H2O2 decreased the maximum velocity (Vmax) of phosphate and alanine uptake by 50 and 62%, respectively, whereas Michaelis constant (Km) values were unchanged. H2O2 also decreased Na-K-ATPase activity, measured by ouabain-sensitive rubidium influx, and this effect was independent of H2O2-induced ATP depletion. A lipid-soluble antioxidant, d-alpha-tocopherol (20 microM, 24 h), prevented H2O2-induced decrease in Na-coupled uptake and Na-K-ATPase activity. These results indicate that H2O2 affects Na-dependent phosphate and alanine uptakes and suggest that this effect may be related at least, in part, to a decrease in Na transmembrane gradient, since H2O2 also affects Na-K-ATPase activity. The protective effect of d-alpha-tocopherol suggests that peroxidation of the membrane lipids is likely to be involved in the observed effects.


p-Aminohippurate transport in airways: competitive inhibition. p-Aminohippurate (PAH) transport in canine tracheal epithelium occurs by a HCO3- -PAH exchange process that is located on the luminal membrane and is inhibited by stilbene derivatives. The effects of increasing concentrations of other organic anions, including probenecid (10-250 microM), dibutyryl adenosine 3',5'-cyclic monophosphate (cAMP; 10-1,000 microM), phenol red (10-250 microM), and urate (25-500 microM), and the organic cation tetraethylammonium bromide (TEA; 250 microM) on PAH transport were examined in canine tracheal epithelium mounted in Ussing chambers. Neither phenol red, urate, nor TEA had any effect on electrophysiological properties or unidirectional or net PAH fluxes. In contrast, beginning at 10 microM, both probenecid and cAMP produced significant decreases in unidirectional and net PAH absorption without change in unidirectional PAH secretion. The initial change in net PAH absorption occurred in the absence of any change in electrophysiological properties. Higher concentrations of both probenecid and cAMP produced further decreases in net PAH absorption and significant changes in electrophysiological properties. Probenecid and cAMP increased the apparent Michaelis constant for PAH absorption without affecting maximum transport rate. The inhibitory constant for probenecid was 1.01 +/- 0.06 x 10(-4) M (mean +/- SE) and for cAMP was 5.18 +/- 0.20 x 10(-4) M. We conclude that PAH transport in canine tracheal epithelium demonstrates competitive inhibition by other organic anions and substrate specificity. We also conclude that the affinity of the exchange transport system is higher for probenecid than for PAH and cAMP.


Endothelium-dependent and independent cGMP mechanisms appear to mediate O2 responses in calf pulmonary resistance arteries. Our laboratory has previously described in isolated 1- to 4-mm calf pulmonary arteries, an endothelium-independent contraction to hypoxia that appears to involve the removal of a H2O2-elicited guanosine 3',5'-cyclic monophosphate (cGMP)-mediated relaxation. In this study, we examined the effects of changes in O2 tension (PO2) on isolated endothelium-intact and endothelium-denuded calf pulmonary resistance arteries of approximately 200 microns in diameter. Resistance arteries precontracted with U46619 were found to undergo a contraction when exposed to a PO2 of 24-27 Torr (hypoxia) from a Po2 of 150 Torr (O2 atmosphere). This contraction was significantly larger in endothelium-intact than endothelium-removed arteries. In the intact artery, 30 microM nitro-L-arginine (NLA), an inhibitor of the biosynthesis of nitric oxide-like activators of guanylate cyclase, increased tone under O2 atmosphere and reduced the contraction to hypoxia to the level observed in the endothelium-removed artery. Reoxygenation caused a relaxation, which was not dependent on the endothelium or inhibited by NLA. The inhibitor of guanylate cyclase activation, LY83583 (10 microM), increased tone under O2 atmosphere, eliminated the contraction to hypoxia, and inhibited the relaxation to reoxygenation, whereas indomethacin (10 microM) did not alter these responses. Thus modulation of a cGMP mechanism, not involving the endothelium or metabolism of arginine, is a primary mediator of responses to changes in O2 tension, and the endothelium appears to cause an enhancement of the contraction to hypoxia via suppression by hypoxia of the tonic generation of an arginine-derived relaxing factor.


Chronic DOC treatment enhances Na(+)-H+ exchanger activity of beta-intercalated cells in rabbit CCD. Chronic deoxycorticosterone (DOC) treatment is known to increase HCO3- secretion in rabbit cortical collecting ducts (CCD). In this study, we examined whether changes in number or function of intercalated cells (ICC) are induced by DOC treatment. The number of total ICC [acetoxymethyl ester of 2',7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein (BCECF/AM)-positive cells after its luminal loading], and beta-ICC (peanut agglutinin-positive cells) was not different between DOC and control groups in either initial CCD or terminal CCD. To evaluate the single-cell function of ICC, the rate of intracellular pH (pHi) recovery (dpHi/dt, pHU/s x 10(3)) after NH4+/NH3 prepulse was studied in the in vitro microperfused CCD in the presence of HCO3-/CO2 with BCECF/AM. The mean rate of dpHi/dt of beta-ICC in the DOC group was faster than that in the control group (6.19 +/- 0.36 vs. 4.30 +/- 0.41, P less than 0.005, respectively), whereas baseline pHi and buffer capacity were similar in the two groups. The inhibition of basolateral Na(+)-H+ exchanger with 1 mM amiloride eliminated the difference of dpHi/dt between the two groups, indicating the increased activity of basolateral Na(+)-H+ exchanger of beta-ICC in the DOC group. The correction of DOC-induced metabolic alkalosis by oral acid loading abolished the increase in Na+/H+ exchanger activity by chronic DOC treatment. These results suggest that DOC treatment induces a functional change in a single beta-ICC and that this functional change was induced by in vivo acid-base status.


pH dependence of the action of arginine vasopressin in renal collecting tubule. We determined whether extracellular pH (pHe) and intracellular pH (pHi) modulate the cellular actions of arginine vasopressin (AVP) in rat renal papillary collecting tubule cells in culture. AVP significantly increased cellular adenosine 3',5'-cyclic monophosphate (cAMP) production and cellular free calcium concentration ([Ca2+]i). pHe ranging from 6.8 to 8.0 distributed the pHi between 6.94 and 7.27. The acidified pHe reduced the AVP- and forskolin-induced cAMP production, the AVP-mobilized [Ca2+]i, and [3H]AVP receptor binding, and the alkalinized pHe enhanced the AVP- and forskolin-produced cAMP. Intracellular acidification occurred under three different conditions as follows: using carbonyl cyanide-m-chlorophenylhydrazone (CCCP), acetate buffer, and bicarbonate buffer with a reduced concentration of bicarbonate. Intracellular acidification significantly diminished both the AVP- and forskolin-induced increases in cAMP production and the AVP-mobilized [Ca2+]i but did not alter [3H]AVP receptor binding. Intracellular alkalinization by NH4Cl or chloride-free bicarbonate buffer, in contrast, augmented them. These results indicate that alterations in pHi modulate the cellular action of AVP to produce cAMP and mobilize [Ca2+]i in renal papillary collecting tubule cells. Also, reduced receptor binding of AVP is involved in the mechanism of the effects of low pHe.


Attenuation of endothelin effects by a chloride channel inhibitor, indanyloxyacetic acid. We have recently proposed that the actions of endothelin (ET) are in part mediated by opening of chloride channels (K. Iijima, L. Lin, A. Nasjletti, and M. S. Goligorsky. Am. J. Physiol. 260 (Cell Physiol. 29: C982-C992, 1991). In the present study the ability of a chloride channel inhibitor, an indanyloxyacetic acid (IAA-94), to block ET-induced effects was examined in cultured vascular smooth muscle cells (VSMC) by spectrofluorometry and direct videomicroscopic visualization of the renal microcirculation in isolated perfused hydronephrotic kidneys (IPHK). A fluorescein isothiocyanate (FITC)-labeled IAA-94 analogue showed specific binding to VSMC. IAA-94 (30 microM) neither affected basal cytosolic calcium concentration ([Ca2+]i) in VSMC nor peak response to ET, but it significantly curtailed sustained elevation of [Ca2+]i (half-time recovery was 147 +/- 23 vs. 248 +/- 33 s in control, P less than 0.05). IAA-94 blunted ET-induced membrane depolarization from 24.5 +/- 3.3 to 8.0 +/- 1.8 mV. In IPHK, ET constricted afferent arterioles (AA) by 29 +/- 2% (18.7 +/- 0.8 to 13.2 +/- 0.6 microns, P less than 0.001). Isradipine reversed this ET-induced vasoconstriction. Pretreatment with IAA-94 did not alter AA diameter, but markedly attenuated ET-induced AA constriction (reduction of AA diameters by only 9 +/- 2%, P less than 0.001). The subsequent addition of isradipine (0.1-1 microM) did not further dilate AA. Our data indicate that IAA-94 markedly attenuates AA vasoconstriction elicited by ET and suggest that ET-induced opening of chloride channels, membrane depolarization, and subsequent activation of voltage-dependent calcium channels contribute to the vasoconstrictor mechanisms of this peptide.


Mercury blocks Na-K-ATPase by a ligand-dependent and reversible mechanism. An inhibitory receptor for cardioactive steroids such as digoxin and ouabain is located at the extracellular surface of the Na-K-adenosinetriphosphatase (ATPase) molecule. Besides cardioactive steroids, mercury is a potent inhibitor of the Na-K-ATPase activity. The half-maximal inhibitory concentration (IC50), determined within 30 min at 37 degrees C at 1 microgram protein/ml, was 200 nM, despite the presence of 1 mM EDTA; the IC50 decreased with increasing protein/inhibitor ratio, and it reached 2.7 microM at 0.1 mg protein/ml and 20 microM at 1 mg protein/ml. The IC50 for Na-K-ATPase inhibition by the diuretic compound mersalyl was 4 and 5 microM for the nondiuretic p-chloromercuribenzenesulfonic acid at 0.1 mg protein/ml. The IC50 for HgCl2 inhibition was modulated by the presence of EDTA as well as by the pump ligands Mg, Na, K, and ATP. The E2 conformation of the Na-K-ATPase molecule was more sensitive to HgCl2 than the E1 conformation. The mercury antidote 2,3-dimercapto-1-propanesulfonic acid was able to reactivate approximately 70% of the blocked enzyme. In conclusion, a metal-binding domain of the Na-K-ATPase molecule with particular high affinity for Hg(II) was described functionally in the present work. Therefore Na-K-ATPase belongs to the metal-binding proteins. Metals may modulate the cellular expression and activity of the system by interacting with its metal-binding interface.


Mercury weakens membrane anchoring of Na-K-ATPase. The presence of circulating inhibitors able to decrease the renal Na-K-adenosinetriphosphatase (ATPase) activity (natriuretic hormones) was postulated some 30 years ago. In the present work, the natriuretic inhibitor HgCl2 was selected as a model compound for the structural characterization of a possible natriuretic pathway for Na-K-ATPase modification. The structural effects of Na-K-ATPase inhibition by HgCl2 were assessed by trypsinolysis of the blocked enzyme in comparison with untreated preparations. The results show that inactivation of Na-K-ATPase by HgCl2 leads to the release of the alpha-subunit from the membrane preferentially in the E2 conformation but also in the E1 conformation. Apparently, HgCl2 weakens the membrane anchoring of the alpha-subunit, presumably by loosening the alpha-beta-subunit interaction. By this mechanism, the sensitivity of the Na-K-ATPase to extracellular drugs, hormones, and antibodies, as well as to intracellular proteases and other regulatory factors, could be altered.


Mercury inhibits Na-K-ATPase primarily at the cytoplasmic side. The investigation of active Na-K transport inhibition by mercury is difficult to perform in a cell because of the presence of numerous other membrane and intracellular proteins modifiable by mercury. Thus purified Na-K-adenosinetriphosphatase (ATPase) molecules performing active transport in an artificial membrane are required to demonstrate unequivocally the inhibition of active transport by mercury. We made use of a single population of Na-K-ATPase liposomes filled with ATP and Na to show mercury inhibition of active 86Rb transport mediated by both the inside-out and right-side-out pumps in the same liposome. The effect of HgCl2 on the Na-K-ATPase in cell-like and reversed orientation was measured in comparison with convallatoxin. A dilution series showed that 10 microM externally added HgCl2 inhibited the active 86Rb transport at the cytoplasmic side first; at 50 microM both pump populations were blocked, indicating either membrane permeation by HgCl2 and inhibition at the internal intracellular domains or onset of extracellular action at higher HgCl2 concentration. The results show that the metal-binding interface of Na-K-ATPase molecule is profoundly implicated in active ion transport and that the intracellular part of the Na-K-ATPase molecule presents the primary target for mercury action.


Stretch- and volume-activated channels in isolated proximal tubule cells. Apical and basolateral channels were studied in isolated proximal tubule cells of Necturus kidney. Many of these isolated cells maintained their polarity, with clearly delineated apical and basolateral regions. A 20-pS stretch-activated (SA) cation-selective channel was identified at the apical side of these cells. This channel was permeable to Ca, K, and Na but was not significantly gated by either membrane potential or cytosolic Ca. Negative pipette pressure (15 cmH2O) increased the open probability (Po) of this channel from 0.04 +/- 0.02 to 0.26 +/- 0.08 (n = 6). Two types of Ca-independent, mechanosensitive, K-selective (SAK) channels were identified at the basolateral surface of polarized proximal tubule cells, i.e., a 30-pS long-open time (50 +/- 7 ms) channel (n = 9), and a 46-pS short-open time (1.3 +/- 0.7 ms) channel (n = 10). Pipette suction (-12 cmH2O) increased the Po of the short-open time channels from 0.008 to 0.015 and increased the Po of the long-open time channel from 0.03 to 0.19. The effect of swelling was studied with isolated cells suspended at the tip of patch pipettes. A 50% dilution of the bath doubled cell volume, hyperpolarized the membrane potential by 11 +/- 0.7 mV, and increased the Po of the basolateral SAK channels. This was followed by a spontaneous regulatory volume decrease (RVD), repolarization of the membrane potential, and a decrease in Po. In contrast, isosmotic (bath side) replacement of an impermeant anion (methanesulfonate) with a permeant anion (Cl) doubled cell volume in 5 min but without a subsequent RVD. This sustained swelling hyperpolarized the cell potential by 5.5 +/- 0.7 mV (n = 16) and increased the Po of short-open time channel by a factor of 2.3 from 0.03 +/- 0.01 to 0.07 +/- 0.02 (n = 6). The increase in Po was primarily produced by a reduction in the interburst closed time, which decreased from 142 +/- 43 ms in K methanesulfonate to 36 +/- 11 ms in KCl solutions. These results are consistent with the hypothesis that cell swelling activates Ca-independent K channels at the basolateral membrane of renal proximal tubule. Efflux of K through these channels may partially mediate renal cell volume regulation.


Extracellular pH modifies adaptive response to high K+ in cultured canine kidney cells. The chronic interactive and independent effects of extracellular pH and K+ on renal Na(+)-K(+)-adenosinetriphosphatase (ATPase) activity and active K+ transport were studied in the Madin-Darby canine kidney (MDCK) cell line. Confluent cell monolayers were incubated for 24 h in control (4 mM) or high (7.5 mM) K+ medium at acid (6.8) or neutral (7.4) pH. Under acid pH conditions, exposure to high K+ elicited a rise of 133% in maximum Na(+)-K(+)-ATPase activity and 66% in active K+ uptake. In contrast, high K+ had no effect on enzyme activity or K+ uptake at neutral pH. Detergent-activated Na(+)-K(+)-ATPase assay demonstrated a latent pool of enzyme at acid pH-control K+, which seemed to account entirely for the increase in Na(+)-K(+)-ATPase activity after exposure to high K+. The effects of pH appeared unrelated to HCO3- and Cl- concentration in the extracellular environment. We conclude that the upregulatory effect of high K+ on renal Na(+)-K(+)-ATPase is pH dependent. The data suggest that a pool of catalytically inactive enzyme exists only at acid extracellular pH at K+ concentrations in the normal physiological range and that K+ adaptation, at least initially, is the result of recruitment of this latent intracellular pool. In the intact cell extracellular K+ and luminal pH may interact to modify catalytic turnover rate as well as bioavailability of Na(+)-K(+)-ATPase.


Dietary Na and ACE inhibition effects on renal tissue angiotensin I and II and ACE activity in rats. This study was designed to improve and validate methods for the accurate and consistent quantitation of angiotensin (ANG) I and II levels in rat kidney and to determine the effects on renal ANG I and II of changes in dietary sodium intake and ANG-converting enzyme (ACE) inhibition. Kidneys from pentobarbital-anesthetized rats were rapidly removed and homogenized in methanol before extraction and purification of ANG peptides by solid-phase extraction and high-performance liquid chromatography (HPLC). Recoveries of 125I-ANG I and II were greater than 80%. Reversed-phase HPLC of the partially purified methanol extract showed that greater than 75% of the ANG I- and greater than 82% of the ANG II-like immunoreactivity coeluted with ANG I and II, respectively. Dietary sodium deprivation (0.003 meq/g) and excess (1.34 meq/g) for 7 days significantly (P less than 0.01) increased and decreased renal ANG I (296 +/- 30 and 82.6 +/- 15.8 vs. 161 +/- 18 fmol/g) and ANG II (216 +/- 16 and 45.6 +/- 11.8 vs. 98 +/- 16 fmol/g) contents, respectively. Plasma ANG I and II levels showed similar changes. ACE activity was significantly upregulated by sodium deprivation in both kidney (44% increase) and plasma (30% increase). In rats fed normal chow, infusion of enalaprilat for 1 h abolished plasma ACE activity but decreased renal ACE activity by only 58%. ACE inhibition increased renal and plasma ANG I levels 2.8- and 12-fold, respectively, and decreased renal and plasma ANG II levels 75-78%.(ABSTRACT TRUNCATED AT 250 WORDS)


Sarcolemmal calcium transport in congestive heart failure due to myocardial infarction in rats. Because Na(+)-Ca2+ exchange and Ca2+ pump are thought to play a role in sarcolemmal Ca2+ movements, we examined the Na(+)-dependent Ca(2+)-uptake and ATP-dependent Ca(2+)-uptake activities in failing heart after myocardial infarction in rats. The left coronary artery was ligated, and the viable left ventricle was used 4, 8, and 16 wk later; sham-operated animals served as controls. Increased left ventricular diastolic pressure and decreased positive and negative change in pressure over time were observed in experimental animals at 4, 8, and 16 wk; these changes were associated with accumulation of fluid in the abdominal cavity. The sarcolemmal Na(+)-dependent Ca2+ uptake was depressed in 4-, 8-, and 16-wk experimental hearts. The decrease in sarcolemmal Na(+)-dependent Ca2+ uptake in failing hearts was seen when the activity was assayed either as a function of time or Ca2+ concentration; a depression of maximal velocity without any change in activity constant for Ca2+ was observed. No alteration in the Ca2+ pump (ATP-dependent Ca2+ accumulation and Ca(2+)-stimulated adenosinetriphosphatase) activities was evident in the 4-, 8-, and 16-wk experimental groups. These data suggest that changes in the Na(+)-dependent Ca2+ handling by the sarcolemmal membrane may be associated with contractile abnormalities in this model of congestive heart failure.


Development and characterization of a model of eosinophil-mediated cardiomyopathy in rats infected with Toxocara canis. This study begins testing the hypothesis that a causal relationship exists between hypereosinophilia and cardiac dysfunction. Rats infected with the nematode Toxocara canis develop marked hypereosinophilia, with peak blood eosinophil levels of approximately 3,500 eosinophils/mm3 whole blood observed approximately 14 days postinfection. Corresponding to the increase in blood eosinophils of infected animals was a decrease in cardiac performance. By 14 days postinfection, cardiac work had declined approximately 25% while negative first derivative of pressure (-dP/dt) fell approximately 10%. As the extent of hypereosinophilia declined from a peak of approximately 3,500 eosinophils/mm3 whole blood to a new steady state of approximately 1,000 eosinophils/mm3, the degree of cardiac dysfunction also was reduced. Cardiac work was 10-15% less in rats 28-42 days postinfection while -dP/dt was 5% depressed in these animals. Myocardial dysfunction was also observed following exposure of perfused hearts obtained from uninfected rats to buffer containing activated eosinophils. The hearts exposed to activated eosinophils exhibited marked histological alterations, characterized by distention of the intermyocyte space, increased pericapillary space, and focal losses of striated staining pattern. These changes were associated with the accumulation of eosinophils within the myocardium, as evidenced by the cytochemical demonstration of eosinophil peroxidase activity within the heart. The data support the hypothesis that hypereosinophilia can lead to cardiac dysfunction.


Myocardial beta-adrenergic and mechanical properties in pacing-induced heart failure in dogs. Forty-eight dogs had pacing overdrive at 250 beats/min for 4-6 wk until heart failure developed. Myocardium from pacing dogs had a decrease in tension and maximum unloaded velocity of shortening (Vmax). Pacing dogs had an increase in circulating catecholamines during exercise but a lower maximal heart rate (214 +/- 19 vs. 241 +/- 26 beats/min, P less than 0.05). A blunted chronotropic response to isoproterenol was also found. However, despite a decrease in beta-adrenergic receptor density (80 +/- 14 vs. 122 +/- 14 fmol/mg, P less than 0.001) and a decrease in beta-adrenergic signal transduction [isoproterenol-induced adenosine 3',5'-cyclic monophosphate (cAMP) production 230 +/- 45 vs. 339 +/- 64 pmol.mg-1.min-1, P less than 0.001], Vmax normalized in response to isoproterenol in pacing dogs (2.3 +/- 0.6 vs. 2.2 +/- 0.5 Lmax/s, NS, where Lmax is length at which maximum developed tension occurs). Tension did not normalize (8 +/- 2 vs. 12 +/- 2 g/mm2, P less than 0.001). Thus in this model of heart failure, despite widespread evidence of decreased beta-adrenergic signal transduction, indexes of shortening but not force generation normalize in response to isoproterenol.


Similarities between effects of superoxide-mediated endothelium-derived relaxing factor and cromakalim. A stable endothelium-derived relaxing factor has been reported to be generated on exposure of endothelial cells to the superoxide anion. In this study, we first evaluated the effects of the relaxing factor and cromakalim on mechanical tone and, second, assessed their consequences on the 86Rb efflux rate. On application of hypoxanthine-xanthine oxidase to a bath for generating superoxide anion, the precontracted rabbit mesenteric artery exhibited another transient increase in contraction, followed by sustained relaxation. This relaxation was lost in the K(+)-physiological salt solution (PSS) (greater than 35 mM) and was inhibited by glibenclamide (10 microM) but not by N-methyl-L-arginine or methylene blue. Hypoxanthine-xanthine oxidase application did not increase either basal or stimulated synthesis of guanosine 3',5'-cyclic monophosphate. In the presence of 2 mM ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid and 10 mM MgCl2, the relaxing factor caused a significant increase in 86Rb efflux from the aortic and mesenteric arterial segments, as did the cromakalim. The increased 86Rb efflux, either by the relaxing factor or by cromakalim, was wholly inhibited by glibenclamide. These results suggest that superoxide-mediated endogenous relaxing factor may have a similar mechanism of action to cromakalim in vasodilatation.


Increased concentration of leukotriene B4 but not thromboxane B2 in intestinal lymph of cats during brief ischemia. Mesenteric ischemia stimulates both A delta- and C-fiber afferents to reflexly activate the cardiovascular system. Leukotriene B4 (LTB4) concentration is increased in intestinal mucosa following prolonged ischemia (3 h) followed by reperfusion. Because LTB4 sensitizes afferent nerve endings in the skin, we determined whether LTB4 is produced during brief mesenteric ischemia and thus would be present to sensitize afferent nerve endings in the abdominal visceral region. Cannulas were placed in the portal vein and in a mesenteric lymphatic vessel distal to the lymph node. Mesenteric lymph and portal venous immunoreactive LTB4 (iLTB4) and immunoreactive thromboxane B2 (iTxB2) concentrations were measured before, during, and after 5-7 min of ischemia induced by occlusion of the descending thoracic aorta in cats. Simultaneously, lymph and plasma lactate concentrations were measured. During arterial occlusion, femoral arterial pressure dropped to less than 30 mmHg, and portal venous and mesenteric lymph lactate concentrations were increased significantly (3.3 +/- 0.6 to 6.3 +/- 1.0 mM and 5.2 +/- 0.9 to 7.2 +/- 1.1 mM, respectively, P less than 0.05). During ischemia, iLTB4 concentration increased in lymph from 261 +/- 70 to 424 +/- 102 pg/0.1 ml (P less than 0.05) but did not increase in portal venous blood (135 +/- 26 vs. 168 +/- 44 pg/0.1 ml, control vs. ischemia). iTxB2 concentration was not increased during ischemia in either portal venous blood or lymph (12 +/- 4 to 24 +/- 9 pg/0.1 ml and 19 +/- 7 to 24 +/- 11 pg/0.1 ml, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)


Rainbow trout hepatocyte beta-adrenoceptors, catecholamine responsiveness, and effects of cortisol. Hepatocyte beta-adrenoceptors were characterized in trout with chronically raised plasma cortisol levels (132.1 +/- 14.8 ng/ml, n = 8, 11-12 days) and compared with shams (1.8 +/- 0.9 ng/ml, n = 8) using radioreceptor assay techniques. Hepatocytes prepared from sham trout possessed 1,696 +/- 179 beta-adrenoceptors/cell. These receptors were characterized as beta 2-adrenoceptors based on the potency order of specific inhibition of CGP binding. The number of putative surface beta 2-adrenoceptors significantly increased to 6,005 +/- 1,165 receptors/cell, in hepatocytes from trout exposed to the elevated plasma cortisol concentration. The physiological significance of the increase in hepatocyte surface receptors was assessed by the in vitro responsiveness of hepatocytes to a range of epinephrine concentrations (10-1,000 nmol/l). Both total glucose production and intracellular adenosine 3',5'-cyclic monophosphate content, indicators of epinephrine responsiveness, were enhanced as a result of chronically raised levels of plasma cortisol. We suggest that these cortisol-mediated alterations in the adrenergic responsiveness of trout hepatocytes may ultimately enhance the ability of the liver to supply glucose to the fish during acute stress after extended periods of chronic stress.


Substance use disorder diagnostic schedule (SUDDS): the equivalence and validity of a computer-administered and an interviewer-administered format. In order to evaluate the equivalence of interviewer-administered and computer-administered forms of the substance use disorder diagnostic schedule (SUDDS), both forms were presented to 100 substance-dependent inpatients. An additional 101 psychiatric outpatients were administered one form or the other. For patients who received both forms of the SUDDS, the percentage agreement ranged from 96% for the classification of a lifetime diagnosis of alcohol abuse/dependence to 88% for the classification of current diagnosis of alcohol abuse/dependence (kappa coefficients ranged from 0.709 to 0.865). Overall agreement with a clinician diagnosis (validity) and the two forms of administration varied from 100% for computer-generated diagnosis of current alcohol abuse/dependence to 71% for computer-generated lifetime diagnosis of drug abuse/dependence, when stratified by number of symptoms reported. No consistent differences were found in the performances of the two forms of the SUDDS, and we conclude that they may be used interchangeably.


Effect of fluoxetine on alcohol consumption in male alcoholics. To test the effect of inhibiting serotonin uptake on voluntary alcohol intake, 20 alcohol-dependent males were housed on a locked hospital ward with 60-ml drinks of 97.5 proof alcohol available in a fixed interval drinking decision paradigm 13 times each day. After a 3-day, single-blind placebo baseline period, 10 subjects each received the serotonin uptake blocker fluoxetine (up to 80 mg po daily) or placebo double-blind for 28 days. The fluoxetine group had a 14% lower alcohol intake during the 1st week only, associated with a lower proportion of requests for alcohol and less craving for alcohol (as rated by research staff). There were no significant effects in later weeks, nor any differences in scores on the Hamilton Depression and Anxiety Scales or the Hopkins Symptom Checklist.


Ethanol exposure results in a transient decrease in human platelet cAMP levels: evidence for a protein kinase C mediated process. At concentrations between 2 and 32 mM, ethanol is shown to depress human platelet cAMP levels. The effect is biphasic, maximal at 30 sec, with platelet concentrations of cAMP returning to baseline values at higher ethanol concentrations and at longer incubation times. The cAMP lowering effect of ethanol can be blocked by a phosphodiesterase (PPDE) inhibitor, 3-isobutyl-1-methyl-xanthine (IBMX), at a concentration of 2 mM, suggesting that an increase in PPDE activity may be responsible for this effect. Exposure of platelets to 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine (H7), a protein kinase C (PKC) inhibitor, blocks the ethanol-induced decrease in platelet cAMP, suggesting ethanol may be acting through activation of PKC.


Selective changes in GABAergic transmission in substantia nigra and superior colliculus caused by ethanol and ethanol withdrawal. One of ethanol's actions after acute exposure is anticonvulsant activity whereas withdrawal from chronic ethanol exposure increases convulsant activity. An increase in neuronal transmission in the GABAergic pathways from striatum to the substantia nigra (SN) and a decrease in GABAergic transmission from SN to superior colliculus (SC) both appear to play a major role in inhibiting seizure propagation. If this is the case, then the changes in seizure sensitivity caused by ethanol may be expected to affect GABAergic transmission in opposite ways in SN and SC. We measured the effects of in vitro ethanol on pre- and postsynaptic indices of GABA transmission using SN and SC tissue from both ethanol-naive rats and rats given ethanol in their drinking water for 24 days and then withdrawn for 24 hr, a treatment that decreases seizure latency. While ethanol inhibited 3H-GABA release from slices of SC at low concentrations (20-100 nM), much higher concentrations were required to inhibit release from SN (100-500 mM). In fact, release from SN was increased by low concentrations of ethanol. Ethanol in vitro (20-1000 mM) also inhibited specific binding of 35S-TBPS to the GABAA receptor but this effect was similar in both potency and efficacy in SC and SN. Next, the in vitro effects of ethanol were measured in rats that had consumed an average of 9.8 g ethanol/kg body weight/day and were then withdrawn for 24 hr. Ethanol inhibition of 3H-GABA release from SC was significantly less in ethanol-treated rats compared to controls whereas the inhibitory effect of ethanol was increased in SN from ethanol-treated rats.(ABSTRACT TRUNCATED AT 250 WORDS)


Blood and serum thiamin and thiamin phosphate esters concentrations in patients with alcohol dependence syndrome before and after thiamin treatment. The blood and serum concentrations of free thiamin and its three phosphate esters were determined concomitantly by a new high-performance liquid chromatography (HPLC) method in 30 patients with alcohol dependence syndrome on admission to hospital and 24 hr after thiamin injection. We studied 24 men and 6 women; mean age, 50 years (range 21 to 69); mean ethanol consumption during the last 30 days, 164 +/- 119 g/day. A control group included 40 healthy volunteers (25 men, 15 women), of whom 10 were given the same thiamin injection as were the patients. Thiamin monophosphate was significantly reduced in the patients compared with controls before treatment (men 2.9 +/- 2.3 and 5.9 +/- 3.1 nmol/liter) and after (8.1 +/- 5.1 and 19.5 +/- 8.1 nmol/liter). On admission, free thiamin and thiamin diphosphate were similar in controls and in patients in whole blood (B) and serum (S) and increased similarly after treatment (mean B-thiamin diphosphate in male patients: 149 +/- 64 to 238 +/- 88 nmol/liter, in controls: 179 +/- 40 to 289 +/- 18 nmol/liter). However, seven patients had extremely high free thiamin values. The phosphorylation ratio was lower in patients than in controls (p less than 0.05), before and after treatment. Finally, the mean B-diphosphate was lower in patients not taking vitamins (116 +/- 48 nmol/liter and 172 +/- 57 nmol/liter) and in patients with polyneuropathy (118 +/- 54 nmol/liter and 173 +/- 52 nmol/liter), compared with the other patients.(ABSTRACT TRUNCATED AT 250 WORDS)


[Is the lithium chloride-coated heat and moisture exchanger a danger for patients?]. Such hygroscopic compounds as LiCl, CaCl2, and MgCl2 are used to improve water retention capacity and, as a consequence, the effectiveness of heat and moisture exchangers (HME). Resorption of these substances via the bronchopulmonary tract and a resulting systemic action cannot be excluded, especially if additional active moisturizing devices are used. The narrow therapeutic range of lithium is known, as are its unwanted side effects, such as nausea, vomiting, somnolence and even cardiac arrhythmia. These are symptoms that also frequently occur during anaesthesia and intensive care, so that differentiation against effects of lithium is nearly impossible. We investigated whether, in theory and in practice, LiCl-coated HME could result in effective Li plasma concentrations. We measured (1) total LiCl content of HMEs, (2) release of this content, simulating the worst-case situation with a breathing model, and (3) lithium plasma concentrations of adult patients being ventilated during anaesthesia with a rebreathing circuit and LiCl-coated HME, but with no additional active moisturizing system incorporated. RESULTS. The results show striking differences with LiCl content ranging from 3 to 251 mg varying not only between different types of HME but also within the same lots. After 20 min of ventilation more than 90% of the LiCl coating was rinsed into the test lung of the breathing model. In practical use, we observed an increase in lithium plasma concentration in 3 of 20 investigated patients. The plasma values of maximum 49.5 micrograms/l (= 0.007 mmol/l) do not amount to potentially toxic concentrations. Nevertheless, clinically relevant concentrations might occur in patients with small distribution volumes, e.g. newborns or infants with frequent exposition within short intervals such as in intensive care units. The differences in lithium content also indicate qualitative differences in water retention capacity. Because of the potential side effects of lithium, we prefer qualitatively equivalent HMEs, e.g., with MgCl2 or CaCl2 as hygroscopic substance.


Enhancement of the thermal and storage stability of urease by covalent attachment to phospholipid-bound silica. Urease was immobilized directly on silanized silica surfaces carrying alkyl moieties with terminal carboxylic groups. The enzyme was also covalently attached to phospholipid-bound silanized silica surfaces through the terminal carboxyl moiety on the sn-2 acyl chain of the lipid. The surfaces were characterized by X-ray photoelectron spectroscopy and ellipsometry. The activity of the immobilized urease was determined by UV spectrophotometry using a urea/bromocresol purple substrate. The enzymic activity decreases exponentially upon storage under dry solid conditions for 1 week or upon heating to 100 degrees C in the case of the silane/enzyme surfaces. On the other hand, the enzyme immobilized on phospholipid-carrying silica surfaces retained its entire original activity under dry storage or heat treatment conditions. Such immobilized urease systems could find extensive applicability in the design of in vivo dialysis equipment or for on-line monitoring of urea.