Immediate and late outcome of percutaneous balloon mitral valvotomy in patients with significantly calcified valves

We assessed immediate and late outcome in 55 patients with significantly calcified valves (group 1) after balloon mitral valvotomy and compared the results with those from 60 patients with noncalcified or minimally calcified valves (group 2). After valvotomy, mitral valve area increased from 1.03 +/- 0.30 cm2 to 1.64 +/- 0.35 cm2 (p = 0.0001) by echo planimetry in group 1 but was significantly smaller than the mitral valve area in group 2 after valvotomy (1.94 +/- 0.38 cm2; p = 0.0001). At a mean follow-up period of 30 months (range 2 to 81 months), 51% of patients in group 1 and 83% in group 2 were symptom free (p = 0.0002). In group 2, 15 (27%) patients and in group 2, 4 (7%) patients had cardiac events (p = 0.003). The risk ratio for cardiac events was 4.3 times greater in group 1 than in group 2. In group 1, the risk ratio for cardiac events was 3.2 times higher in patients age > or = 65 years and in patients with atrial fibrillation. The 6-year cumulative cardiac event-free survival rate was 64% in group 1 and 90% in group 2 (p = 0.005). In 75 (65%) patients who had follow-up echocardiographic study (35 in group 1 and 40 in group 2), mitral valve area decreased to 1.48 +/- 0.42 cm2 at follow-up in group 1 (p < 0.01) and to 1.77 +/- 0.50 cm2 in group 2 (p = 0.3). Restenosis occurred in 16 (46%) of 35 patients in group 1 and 10 (25%) of 40 in group 2 (p = 0.06).(ABSTRACT TRUNCATED AT 250 WORDS)

Endothelium-dependent regulation of coronary tone in the neonatal pig

We examined the effects of endothelium-dependent responses on coronary perfusion pressure (CPP) in isolated, blood-perfused neonatal pig hearts under conditions of controlled coronary flow. Baseline CPP was increased 8%-21% by the cyclooxygenase inhibitor indomethacin (10-100 microM), and 30%-92% by NG-monomethyl-L-arginine (L-NMMA, 10-100 microM), an inhibitor of nitric oxide (NO) synthase, suggesting that both prostaglandin and nitric oxide synthesis contribute to basal coronary tone. Both acetylcholine (ACh) and bradykinin (BK) decreased CPP. These effects were enhanced by preconstriction with endothelin-1. L-NMMA markedly attenuated BK-induced coronary vasodilation and converted the ACh response to constriction, indicating a significant role for NO release in these responses. After 1 h of total, global normothermic ischemia and 45 min of reperfusion, vasoconstrictor responses to endothelin-1 and ACh were enhanced, while BK-induced dilation was significantly reduced. L-Arginine supplementation during reperfusion did not restore vasodilatory responses to ACh or BK. The magnitude of L-NMMA-induced coronary vasoconstriction during reperfusion was similar to that observed without ischemia-reperfusion. Coronary vasodilation in response to sodium nitroprusside, a NO precursor that causes endothelium-independent vasodilation by directly activating smooth muscle guanylate cyclase, was unaffected by ischemia-reperfusion. We conclude that NO production in the neonatal coronary circulation contributes to both basal tone and the response to ACh and BK. After ischemia-reperfusion, basal NO production and smooth muscle relaxation mediated by guanylate cyclase are intact, whereas agonist-stimulated dilation is significantly impaired.

Thermodilution left-sided cardiac output for valve area determination after balloon mitral valvotomy

This study was conducted to establish the validity of left-sided cardiac output measurement with a Swan-Ganz catheter and assess its accuracy in estimating mitral valve area (MVA) by the Gorlin formula. The use of right-sided cardiac output after balloon mitral valvotomy (BMV) can give inaccurate measurements for Gorlin-derived MVA because of the atrial septal defect (ASD) created during the procedure. The left-sided cardiac output was measured with a Swan-Ganz catheter (proximal port in the left atrium and then in the left ventricle, and distal port in the ascending aorta) in 10 consecutive patients before and after BMV. Gorlin-derived MVA cardiac output by this method was compared with (1) Gorlin-derived MVA by means of right-sided cardiac output with and without balloon occlusion of the ASD and (2) MVA measured by echocardiography. Before BMV, a close agreement with a good correlation between left-sided and right-sided cardiac output was found (r = 0.83, p = 0.006). Furthermore, Gorlin-derived MVA by cardiac output with either method was comparable with valve area by echo. After BMV, left-sided cardiac output correlated well (r = 0.92, p = 0.0002) and was comparable with right-sided cardiac output with occlusion of the ASD (mean difference 0.17 +/- 0.49 L/min, p = 0.3) but was significantly lower than the value obtained with open ASD (mean difference 0.93 +/- 0.77 L/min, p = 0.004). Comparison of the correspondent MVAs yielded similar results. Gorlin-derived MVA with left-sided cardiac output and MVA by echo were also similar.(ABSTRACT TRUNCATED AT 250 WORDS)

Ethnomycology, biochemistry, and cultivation of Psilocybe samuiensis Guzmán, Bandala and Allen, a new psychoactive fungus from Koh Samui, Thailand

Several specimens of Psilocybe and Copelandia species in Koh Samui, Thailand were recently collected for herbarium deposit and scientific study. This paper presents an ethnomycological and biochemical study of one of the species; P. samuiensis Guzmán, Bandala and Allen, a new psychoactive gill fungus reported from Thailand. Mycelium for the cultivation of P. samuiensis was obtained on 6% malt agar from the spores of a dried specimen. The growth of P. samuiensis was similar to that of P. tampanensis Guzmán and Pollock, but more rapid than the mycelium of P. semilanceata (Fr.:Sacc.) Kumm. Laboratory analyses indicates that the alkaloid content in cultured fruit bodies of P. samuiensis is of the same order of magnitude as that found in naturally occurring mushrooms of this species. HPLC analyses of both naturally occurring and in vitro cultivated fruit bodies of P. samuiensis revealed high concentrations of psilocybin and psilocin. Small amounts of baeocystin were also detected. Psilocybin levels varied from 0.23% up to 0.90%. The psilocybin content was highest in the caps. Psilocybin was also found in the cultured non-bluing mycelia of P. samuiensis and varied from 0.24% to 0.32% dry weight. The relative alkaloidal content of psilocybin, psilocin, and baeocystin found in P. samuiensis was similar to that measured in many other psychoactive fungi species, but completely different from that found in P. semilanceata.

Late clinical and echocardiographic follow up after percutaneous balloon dilatation of the mitral valve

OBJECTIVE

To assess the outcome after attempted percutaneous balloon dilatation of the mitral valve in patients with severe mitral stenosis between February 1986 and June 1992.

DESIGN

Clinical state, mitral valve area, and restenosis at follow up were analysed. Mitral valve area as determined by the Gorlin formula, planimetry, and Doppler methods was compared before and after dilatation and at follow up.

SETTING

University hospital.

PATIENTS

176 patients had serial clinical and Doppler echocardiographic follow up and 44 of them also underwent recatheterisation.

RESULT

At follow up 93% of patients were in New York Heart Association functional class I or class II. Mitral valve area (planimetry) increased from 0.97(0.24) cm2 before to 1.86(0.39) cm2 after dilatation (p = 0.0001) and then decreased to 1.72(0.39) cm2 at follow up (p < 0.001); mitral valve area (Doppler) increased from 1.01 (0.24) to 1.89 (0.42) cm2 (p = 0.0001) and then decreased to 1.78(0.40) cm2 (p < 0.05). The overall restenosis rate was 15% and over 90% of the patients were free from cardiovascular events. Age, valvar calcification, echocardiographic score, and mitral valve area after dilatation were found to be determinant predictors of restenosis. In patients who underwent recatheterisation, mitral valve area by the Gorlin method at follow up was comparable with that by planimetry and Doppler methods whereas a significant discrepancy between the three methods was noted immediately after dilatation.

CONCLUSION

Balloon dilatation of the mitral valve provided sustained anatomical and functional improvement in over 80% of patients at late follow up. Older age, heavy calcification, high echocardiographic score, and suboptimal immediate results are significant predictors of restenosis. Doppler echocardiographic examination is the procedure of choice for follow up evaluation.

Synaptonemal complex aberrations in the pseudoautosomal region of X, Y chromosomes in irradiated hamsters

The effects of X-radiation, bleomycin and amsacrine (m-AMSA) on the meiotic chromosomes of male Armenian hamsters were determined by electron microscopic analysis of synaptonemal complex (SC) damage. Pachytene stage cells were analyzed 5 or 6 days following their treatment at putative preleptotene-leptotene stages of meiosis. Of the multiple types of SC aberrations observed to be significantly increased over control levels, lateral element breakage and synaptic anomalies were most prevalent. The focus of these studies was on the sex chromosomes which, in the Armenian hamster, reveal an unusually well-defined pseudoautosomal region. In the XY pair, radiation and chemical treatments caused certain forms of structural and synaptic anomalies which appeared to be preferentially localized to telomeric and/or crossover regions. The nature of these specific aberrations, involving breakage, bridge formation and asynapsis, is not well understood; however, their distributions are suggestive of possible relationships with sites and processes of crossing over.

Low-dose combined therapy with fluvastatin and cholestyramine in hyperlipidemic patients

OBJECTIVE

To compare the low-density lipoprotein (LDL) cholesterol-lowering efficacy of low-dose combinations of cholestyramine and fluvastatin.

DESIGN

Randomized, double-blind, parallel group, placebo-controlled trial with a 24-week double-blind treatment period divided into three phases.

SETTING

Office-based clinics.

PATIENTS

Hypercholesterolemic, with LDL cholesterol of 4.14 mmol/L or greater (> or = 160 mg/dL) and plasma triglycerides of 3.39 mmol/L or less (< or = 300 mg/dL). Four hundred sixty patients were screened; 224 patients were randomized into a double-blind treatment period; 203 completed the study; 6 dropped out because of adverse events.

INTERVENTION

Patients were treated with 10 mg or 20 mg of fluvastatin alone, 8 g or 16 g of cholestyramine alone, or combinations of these fluvastatin and cholestyramine dosages (six treatment groups).

MEASUREMENTS

Changes in lipid variables, particularly LDL cholesterol.

RESULTS

The 10-mg and 20-mg fluvastatin monotherapy groups showed considerable reductions in LDL cholesterol initially (-20.1% [SD, 8.8%] and -20.2% [SD, 10.1%], respectively); these reductions were maintained. Reductions in LDL cholesterol that resulted from the addition of cholestyramine, 8 g/d, to 10 mg of fluvastatin and 20 mg of fluvastatin were greater than those observed with monotherapy (10-mg fluvastatin--[10-mg fluvastatin plus cholestyramine], 9.1%; 95% CI, 3.8% to 14.4%) and 20-mg fluvastatin--[20-mg fluvastatin plus cholestyramine], 11.6%; CI, 6.5% to 16.8%). The increase in cholestyramine dose to 16 g/d in the three combination groups provided only a modest additional response.

CONCLUSIONS

Low-density lipoprotein cholesterol reductions of about 25% to 30% can be achieved with low-dose combination therapy with fluvastatin and cholestyramine. The addition of low-dose resin appears to produce greater overall cholesterol reduction than does a simple doubling of the fluvastatin dosage. The low-dose combination treatment was highly successful in achieving the goals of the National Cholesterol Education Program guidelines.

Spermatid micronucleus analyses of trichloroethylene and chloral hydrate effects in mice

Mice were exposed by inhalation to trichloroethylene (TCE) or by i.p. injection to the TCE metabolite, chloral hydrate (CH). Early spermatids were analyzed for micronucleus (MN) frequency and the presence or absence of kinetochore(s) using fluorochrome-labeled anti-kinetochore antibodies. It was determined that 5 consecutive days of exposure to 5, 50 or 500 ppm TCE during preleptotene through early pachytene stages of meiotic cell development do not result in increased frequencies of spermatid MN. CH at 41, 83 or 165 mg/kg was positive for spermatid MN induction when treatments corresponded to spermatogonial stem cell or preleptotene spermatocyte stages of development; negative results were obtained after treatments of leptotene-zygotene or diakinesis-metaphase stages. The significantly increased levels of MN observed were invariably of the kinetochore-negative type.

Centromere analysis of micronuclei induced by 2-aminoanthraquinone in cultured mouse splenocytes using both a gamma-satellite DNA probe and anti-kinetochore antibody

We have tested 2-aminoanthraquinone (2-AAQ) as a potential aneugen in a cytokinesis-blocked mouse splenocyte micronucleus (MN) assay. Binucleated cells (BNC) were evaluated for MN, and the MN were further probed with two indicators of centromere presence: an anti-kinetochore autoantibody and a DNA probe for the mouse gamma-satellite locus. A dose-dependent increase in the frequency of BNC with MN was observed. At the highest 2-AAQ concentration (10 micrograms/ml), the frequency of BNC containing MN was increased greater than 10-fold over background. Both centromere-positive and centromere-negative MN were significantly increased. At least 62% of MN at all 2-AAQ doses were positive for the gamma-satellite DNA probe, while 30-53% were labeled with the antikinetochore antibody. In contrast with the 2-AAQ results, after treatment with the aneugen demecolcine (positive control), greater than 80% of MN labelled positive with both probes. This discordance in the results with the two probes after 2-AAQ exposure suggests that the mode of action of this chemical may be as an aneugen by disruption of the kinetochore proteins, as a clastogen with a preferential cleavage site at or near the gamma-satellite locus, or both. Our results also suggest that the use of either of these probes individually may not be an adequate measure of centromere presence. Nevertheless, positive results for both markers provides strong evidence that 2-AAQ is aneugenic.

Species identification and chemical analysis of psychoactive fungi in the Hawaiian islands

Several fungi species collected in the Hawaiian Islands have been reported to be psychoactive. Previous chemical analyses together with the present study indicate that 5 coprophilous and one non-coprophilous species occurring in the islands are now known to contain psychoactive alkaloids. At least some of these species are consumed in the Hawaiian Islands, as well as elsewhere, for non-traditional, recreational purposes. These include Copelandia cyanescens (Berk. et Br.) Singer, Copelandia tropicalis (Ola'h) Singer and Weeks (syn. Panaeolus tropicalis Ola'h), Copelandia anomala Murrill, and Panaeolus subbalteatus (Berk. and Br.) Sacc., which have already been described from the Hawaiian Islands. Three more mind-altering fungi and one non-psychoactive species are reported from this archipelago for the first time. These psychoactive fungi include Copelandia bispora (Malençon et Bertault) Singer and Weeks from O'ahu, Copelandia cambodginiensis (Ola'h et Heim) Singer and Weeks from O'ahu, and Amanita muscaria (L.) Hooker from Kaua'i. Panaeolus goossensiae Beeli identified from O'ahu contains tryptamine compounds; however, the psychoactive alkaloids psilocybin and psilocin were not found in this dung species.

An audit of preschool vision screening

An audit was carried out to clarify the dispute surrounding the vision screening test at 3.5 years. The uptake was 53.5%, sensitivity 77%, specificity 96%, and positive predictive value 50%. In particular the uptake was poor and the test needed a clear policy for the future.

Serological titers to bovine herpesvirus 1, bovine viral diarrhea virus, parainfluenza 3 virus, bovine respiratory syncytial virus and Pasteurella haemolytica in feedlot calves with respiratory disease: associations with bacteriological and pulmonary cytological variables

Acute and convalescent serum samples were taken from 59 calves with signs of respiratory disease (cases) and 60 clinically normal animals (controls) during their first month in the feedlot. Sera were analyzed for antibodies to bovine parainfluenza 3 (PI3) virus by hemagglutination inhibition, to bovine viral diarrhea (BVD) virus, bovine respiratory syncytial (BRS) virus and bovine herpesvirus 1 (BHV1) by virus neutralization, and to Pasteurella haemolytica by indirect agglutination (PhIA) and cytotoxin neutralization (PhCN) tests. There was minimal evidence of serological activity to BHV1. Serological activity to the other agents occurred commonly and the prevalence of acute titers and their mean values was similar in case and control groups. Mean convalescent PI3 and P. haemolytica (PhIA) titers were higher in controls than cases (p < 0.01) but, otherwise, convalescent titers did not differ between groups. The incidence of seroconversion was similar in both groups for all agents except for PI3 virus which was more frequent in controls than cases (p < 0.0001). There was a positive association between PhIA and CN seroconversion and isolation of P. haemolytica from bronchoalveolar lavage (BAL) fluid (p < 0.1). The measure of agreement (kappa) between seroconversion with the P. haemolytica PhIA and PhCN tests was 0.51. Bacteriological and cytological evaluations of the respiratory tract were made using BAL. No associations were evident between serological titers and pulmonary cytology. A multivariate logistic analysis was used to evaluate associations between disease status and serological, bacteriological and cytological data. Cases were positively associated with the presence of neutrophils and Pasteurella multocida in BAL fluid and negatively associated with PI3 virus and PhIA seroconversion.

Cytogenetic studies of mice exposed to styrene by inhalation

The data for the in vivo genotoxicity of styrene (STY) are equivocal. To evaluate the clastogenicity and sister-chromatid exchange (SCE)-inducing potential of STY in vivo under carefully controlled conditions, B6C3F1 female mice were exposed by inhalation for 6 h/day for 14 consecutive days to either 0, 125, 250 or 500 ppm STY. One day after the final exposure, peripheral blood, spleen, and lungs were removed and cells were cultured for the analysis of micronucleus (MN) induction using the cytochalasin B-block method, chromosome breakage, and SCE induction. Peripheral blood smears were also made for scoring MN in erythrocytes. There was a significant concentration-related elevation of SCE frequency in lymphocytes from the spleen and the peripheral blood as well as in cells from the lung. However, no statistically significant concentration-related increases were found in the frequency of chromosome aberrations in the cultured splenocytes or lung cells, and no significant increases in MN frequencies were observed in binucleated splenocytes or normochromatic erythrocytes in peripheral blood smears.

Changes in the bacterial flora of the upper and lower respiratory tracts and bronchoalveolar lavage differential cell counts in feedlot calves treated for respiratory diseases

Serial nasopharyngeal swab and bronchoalveolar lavage cultures were used to estimate changes in the bacterial flora of the respiratory tracts of calves during the first month after arrival in the feedlot. Bronchoalveolar lavage (BAL) differential cell counts served to evaluate pulmonary inflammatory changes during this period. Two groups of calves were studied, one consisting of clinically normal controls (n = 60), the other, of cases (n = 59) which received treatment for respiratory disease (penicillin +/- trimethoprimsulfadoxine). A variety of organisms, including Pasteurella multocida, Pasteurella haemolytica, Haemophilus somnus, Mycoplasma bovis and Mycoplasma bovirhinis, were present in the upper and lower airways of both groups during the postarrival period. With the exception of M. bovis, an overall decline in the prevalence of these organisms was observed during the course of the study. In cases, there was a marked decrease in the number of Pasteurella spp. and H. somnus isolates immediately following treatment. For the Pasteurella spp., however, this effect was shortlived as they often appeared to recolonize the respiratory tract within eight days of terminating antimicrobial therapy. Treatment did not appear to affect the frequency of isolating M. bovis. Its prevalence, in both groups of calves, increased to levels approaching 100% during the course of the study. All Pasteurella spp. isolates were tested for susceptibility to several commonly used antimicrobials. Resistance was only evident among P. haemolytica isolated from cases and in every instance this was to a combination of penicillin, ampicillin and tetracycline. Significantly more isolates were resistant after treatment than before. There were BAL differential cell count abnormalities indicative of inflammation in both cases and controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Percutaneous closure of a secundum atrial septal defect and double balloon valvotomies of a severe mitral and aortic valve stenosis in a patient with Lutembacher's syndrome and severe pulmonary hypertension

This is a 43-yr-old female presenting with recurrent atrial septal defect, closed surgically, 10 years prior, severe aortic and mitral stenosis, and severe tricuspid regurgitation. She was considered inoperable because of the severe pulmonary hypertension and the complexity of the disease. A percutaneous umbrella closure of the atrial septal defect in conjunction with mitral and aortic balloon valvotomies could be safely and successfully performed. After significant clinical and hemodynamic improvement, surgery was judged feasible, but was refused by the patient who suddenly expired 8 weeks later. The usefulness of percutaneous therapy as a rescue procedure and the management of patients with Eisenmenger's physiology are discussed.

Kinetochore-staining of spermatid micronuclei: Studies of mice treated with X-radiation or acrylamide

The rodent spermatid micronucleus (MN) assay was used in conjunction with immunofluorescent techniques to distinguish kinetochores in MN following exposure of mice to X-radiation or acrylamide. After either treatment, modest increases in kinetochore-positive MN were observed. Spermatids which had been exposed during meiotic prophase to X-rays (400 cGy) had approximately 10-fold increases in MN compared to controls; up to 15% of the MN observed were kinetochore-positive. Following acrylamide treatment of meiotic prophase cells, there was a doubling of spermatid MN over baseline levels, approximately one-third of which were kinetochore-positive.

Cytological findings in bronchoalveolar lavage fluid from feedlot calves: associations with pulmonary microbial flora

Samples obtained by bronchoalveolar lavage (BAL) were used to evaluate pulmonary cytology in 59 feedlot calves with clinical signs of respiratory disease (cases) and 60 clinically normal comparison calves (controls). Many calves in both case and control groups had inflammatory changes in the lower respiratory tract, as determined by changes in proportions in the BAL differential cell count. Approximately 35% of cases and 40% of controls showed a normal differential cell count. It therefore appeared that the criteria used to select cases for treatment, which were similar to those often used in the field, were poor predictors of lower respiratory tract disease. A positive association was found between an increased proportion of neutrophils in BAL fluid and isolations of Pasteurella multocida and Mycoplasma bovis from BAL fluid.

Comparison of Inoue single-balloon versus double-balloon technique for percutaneous mitral valvotomy

The results of percutaneous mitral valvotomy by means of the Inoue single-balloon (N = 85, group 1) and the double-balloon (N = 322, group 2) techniques were compared in a nonrandomized study. The groups were not significantly different with regard to age, sex, calcification, or hemodynamic values before percutaneous mitral valvotomy. After percutaneous mitral valvotomy, patients in both groups had significant hemodynamic and clinical improvement. The increases in mitral valve area and cardiac output and the decreases in mitral valve gradient, mean pulmonary artery pressure, and mean left atrial pressure were greater in group 2. Mitral valve area determined by the Gorlin method increased 191% in group 2 and 106% in group 1; Doppler-determined mitral valve area increased 133% in group 2 and 98% in group 1. Optimal results were achieved in 93% of the patients in group 2 and 76% in group 1 (p less than or equal to 0.0001). In group 1, 6% of patients had a left-to-right shunt as shown by angiography versus 14% in group 2 (p less than or equal to 0.05). In group 2, 46% of patients had at least a 1+ increase in mitral regurgitation versus 52% in group 1. Among the patients who had an increase in mitral regurgitation, 36% of those in group 1 versus 9% in group 2 had a 2+ or more increase (p less than or equal to 0.001). The mean balloon diameter to anulus ratio was larger in group 2, and the larger the balloon diameter to anulus ratio, the greater the increase in mitral valve area.(ABSTRACT TRUNCATED AT 250 WORDS)

Micronuclei and other nuclear anomalies in buccal smears: methods development

Laboratory work aimed at improving the epidemiologic utility of an innovative genotoxicity assay is described. The exfoliated cell micronucleus assay involves microscopic analysis of epithelial smears to determine the prevalence of micronucleation, an indicator of structural or numerical chromosome aberrations. While the assay holds promise for the study of epithelial carcinogens, it is hampered by the fact that exfoliated cells are moribund and undergo degenerative phenomena that can produce extranuclear objects difficult to distinguish from classical micronuclei. Modifications in the protocol were assessed in sample buccal smears from several study populations: radiotherapy patients, nonusers of tobacco, and snuff users. Refinements in micronucleus scoring criteria and the inclusion of other nuclear anomalies in the scoring system are proposed. We demonstrate that our criteria are successful in detecting excess micronucleation in positive controls. We also provide evidence that other nuclear anomalies are at least as common as micronucleation and that therefore there is the potential for extensive misclassification. Reliability was assessed in duplicate readings.

Micronuclei and other nuclear anomalies in buccal smears: a field test in snuff users

A revised protocol for the exfoliated cell micronucleus assay was field-tested in a population exposed to a genotoxic agent, snuff, at levels associated with a significant increase in cancer risk. The standard assay involves examination of epithelial smears to determine the prevalence of micronucleated cells, an indication of chromosome breakage or mitotic interference. The assay was revised to increase specificity and to include separate scoring of other nuclear anomalies associated with cytotoxicity and genotoxicity. The modified assay was applied to buccal smears of 38 female snuff users and 15 female nonusers recruited from a North Carolina clinic in 1987. The prevalence of micronucleation was elevated in the snuff users as compared with the nonusers (prevalence ratio = 2.4, 95% confidence interval 1.1-5.2) and, to a lesser extent, at the usual contact site as compared with a distal buccal site in the snuff users (prevalence ratio = 1.5, 95% confidence interval 0.9-2.5). The pattern of relative frequencies of several nuclear anomalies provided strong evidence of a cytotoxic effect, the prevalence ratios ranging from 2 to 13. Nuclear degenerative phenomena can be difficult to distinguish from classical micronuclei; thus, the observed association of indicators of cytotoxicity with exposure introduces the possibility of bias away from the null in micronucleus findings due to differential misclassification. Until methods to better distinguish extranuclear bodies of different origins become available, investigators should use the revised protocol and should focus on agents not thought to be cytotoxic.

The microbial flora of the respiratory tract in feedlot calves: associations between nasopharyngeal and bronchoalveolar lavage cultures

The upper and lower respiratory tracts of 59 feedlot calves with clinical signs of naturally occurring respiratory disease (cases) and 60 comparison (control) animals were cultured before treatment, using nasopharyngeal swabs (NPS) and bronchoalveolar lavage (BAL). The most prevalent organisms were Pasteurella multocida and Mycoplasma bovis. Isolations of P. multocida from NPS and BAL fluid were found to be significantly associated with morbidity (p less than or equal to 0.05), but the frequency with which other organisms were isolated from the nasopharynx and lungs was similar in cases and controls. There was evidence of moderate agreement between NPS and BAL isolates at the individual calf level using the kappa statistic, (range of kappa values = 0.47-0.61) but the variability of the kappa statistics was large. Therefore, in an individual calf NPS cultures did not accurately predict BAL cultures. The NPS and BAL culture results were quite similar at the group level, however.

Characterization of eugonic fermenters group EF-4 by polyacrylamide gel electrophoresis and protein immunoblot analysis

Whole-cell lysates and proteinase K-extracted lipopolysaccharide (LPS) of 19 strains of the group eugonic fermenter-4 (EF-4) were analyzed by electrophoresis and protein immunoblotting. These strains were isolated from dog- and cat-bite abscesses in human beings, ferret and human gastric lesions, and cat-lung infections. These strains represent 2 biovar groupings; EF-4a biovars ferment glucose and possess arginine dihydrolase activity, whereas EF-4b biovars do not. Electrophoresis of whole-cell lysates could distinguish between these biovars groups. Electrophoresis of LPS extracts revealed that all strains of EF-4 possess smooth chemotypes. Two strains of EF-4a reacted weekly in protein immunoblots and revealed distinct LPS profiles. These studies suggests that subgroups of EF-4 biovars may exist.

Evidence that methanol inhalation does not induce chromosome damage in mice

Mice were exposed by inhalation to 800 or 4000 ppm methanol for 5 days, and cytogenetic effects were analyzed in blood erythrocytes, lung cells, and testicular germ cells. The results were uniformly negative; no increased frequencies of micronuclei in blood cells, of sister-chromatid exchanges, chromosome aberrations, or micronuclei in lung cells, or of synaptonemal complex damage in spermatocytes were found. From the standpoint of risk assessment, these experimental studies do not reveal any evidence of a cytogenetic hazard associated with inhalation of methanol.

Stage-specific damage to synaptonemal complexes and metaphase chromosomes induced by X rays in male mouse germ cells

Synaptonemal complexes reveal mutagen-induced effects in germ cell meiotic chromosomes. This study was aimed at characterizing relationships between damage to synaptonemal complexes and metaphase I chromosomes following radiation exposure at various stages of spermatogenesis. Male mice were irradiated with doses of 0, 2, or 4 Gy, and spermatocytes were harvested at times consistent with earlier exposures as spermatogonial stem cells, preleptotene cells (premeiotic DNA synthesis), or meiotic prophase cells. After stem-cell exposure, twice as many rearrangements were observed in synaptonemal complexes as in metaphase I chromosomes. Irradiation during premeiotic DNA synthesis resulted in dose-related increases in synaptonemal complex breakage and rearrangements (including novel forms) and in metaphase chromosomal aberrations. Following prophase exposure, various types and levels of damage to synaptonemal complexes and metaphase chromosomes were observed. Irradiation of zygotene cells led to high frequencies of chromosome multivalents in metaphase I without a correspondingly high level of damage in preceding prophase synaptonemal complexes. Thus irradiation of premeiotic and meiotic cells results in variable relationships between damage to synaptonemal complexes and metaphase chromosomes. Interpretations of these relationships are based upon what is known about both radiation clastogenesis and the structural/temporal relationships between synaptonemal complexes at prophase and chromosomes at metaphase I of meiosis.

An ethnomycological review of psychoactive agarics in Australia and New Zealand

A comprehensive review is presented of the recreational and accidental ingestion of psychoactive mushrooms in Australia and New Zealand; 15 recognized species are considered from Australia and eight from New Zealand. Common epithets, potency levels, and methods of ingestion are discussed. Legal aspects involving the use of these psychoactive fungi are noted. In addition, medical and psychoactive effects of these mushrooms and treatment for psilocybian mushroom poisoning are described. Numerous case reports, with commentary, are also presented.