Molecular confirmation of hepatitis A virus from well water: epidemiology and public health implications.

An outbreak of hepatitis A in a rural river-island community was found to be associated with consumption of contaminated well water. Specimens from case-patients, the implicated well, and a cesspool suspected to be the source of contamination were all positive for hepatitis A virus (HAV) RNA by immunocapture reverse-transcription polymerase chain reaction. All isolates were identical over about 400 bases from two capsid-encoding regions of the genome, identifying the chain of transmission. Other wells up to 60 m from the cesspool also contained HAV RNA. In addition, HAV RNA was detected in the contamination source well 6 months after the initial contamination, when fecal coliform bacteria were no longer present. These findings demonstrate the utility of viral detection techniques to evaluate contaminated ground water.

A new method of treatment for pulmonary hypertension in congenital diaphragmatic hernia: experimental study in cats.

This research proposes a new treatment for pulmonary hypertension secondary to perivascular emphysema, the so-called air-block syndrome. Vibrations applied on the thorax can fraction air bubbles around the vessels into smaller ones, facilitating their redistribution and reabsorption, thus reducing the extrinsic compression on pulmonary vasculature. In cats, pulmonary lesions were obtained by continuous insufflation of air at 40 cm H2O for 2 minutes in a lower lobe of the lung. Vibrations applied on the thorax were produced with the same apparatus as used by physiotherapists to eliminate pulmonary secretions. Thirty-three cats were divided into three groups: lesions without treatment, lesions treated by vibrations, and controls. A catheter was inserted in the pulmonary artery for pulmonary artery pressure (PAP) measurements. One carotid was cannulated for arterial pressure and blood gases monitoring. Morphometric analysis of the lung had also to be carried out in all cases. Results showed a very significant decrease on pulmonary hypertension in the treated group after only 20 minutes of treatment by vibrations (P < .004). Results also confirmed the very strong relationship between PAP variations and perivascular emphysema found on postmortem examination (r2 = .64, P < .01). Extrinsic compression decreased from 29% in the untreated group to 21% in the treated one (n = 10 pairs, P < .08). These data suggest that vibrations may be a new simple treatment for pulmonary hypertension, when perivascular emphysema is involved, and could be useful in congenital diaphragmatic hernia as well in other neonatal pathologies.

Comparative study of pharmacokinetics and serum bactericidal activities of cefpirome, ceftazidime, ceftriaxone, imipenem, and ciprofloxacin.

We compared the pharmacokinetics and the serum bactericidal activities of cefpirome, ceftazidime, ceftriaxone, imipenem, and ciprofloxacin. Fifteen healthy volunteers received 1 g of cefpirome, ceftazidime, and ceftriaxone intravenously, 500 mg of imipenem-cilastatin intravenously, and 500 mg of ciprofloxacin orally. High-performance liquid chromatographic assays were used to quantitate unchanged antibiotic in plasma and urine. Serum bactericidal activities were determined against six clinical isolates each of Staphylococcus aureus, Enterobacter cloacae, and Pseudomonas aeruginosa by using a modified microdilution method of Reller and Stratton (L. B. Reller and C. W. Stratton, J. Infect. Dis. 136:196-204, 1977). Overall, cefpirome exhibited pharmacokinetics similar to those of ceftazidime: half-life (t1/2), 1.95 h; concentration at 1 h (C1h), 47 to 49 micrograms/ml for both antibiotics. Ceftriaxone displayed the longest t1/2 (7.65 h) and the highest C1h (137.8 micrograms/ml), while we observed the shortest t1/2 (1.05 h) and the lowest C1h (19.85 micrograms/ml) with imipenem. At 1 h, cefpirome and, even more so, imipenem showed significantly better serum bactericidal activities against S. aureus (1:273 and 1:80) than did the other antibiotics (P less than 0.0005; analysis of variance with randomized block design and Bonferroni correction). Against E. cloacae, we observed the highest serum bactericidal titers at 1 h with cefpirome, and this superiority vis-à-vis the other antibiotics tested was maintained for up to 8 h after dosing. Ceftazidime remained the most active agent tested against P. aeruginosa (serum bactericidal activity titers, 1:43 at 1 h) up to 8 h. In summary, the study showed that cefpirome and imipenem provide more potent serum bactericidal activities than do broad-spectrum cephalosporins against S. aureus; thus, both of these antibiotics should be adequate against serious S. aureus infections. In addition, cefpirome appears to be a promising alternative for treatment of infections caused by E. cloacae and P. aeruginosa.

Generation of monoclonal antibodies reactive with nuclear proteins of human primary breast tumors.

Nuclear proteins were extracted from purified nuclei of human primary breast tumors (BrT) and bladder tumors and of human normal breast, kidney and lymphocytes by enzymatic treatment. SDS-Polyacrylamide gel electrophoresis of nuclear proteins from breast tumors showed different bands in the molecular weight zones from 25 to 220 kDa which were absent or present only as traces in normal breast tissue. Murine monoclonal antibodies (MAbs) have been produced using nuclear extracts of human primary breast tumors as immunogens. Approximately 2,000 hybridomas were generated from 5 hybridizations. According to their reactivity to BrT nuclear extracts and mammary carcinoma cell line MCF-7, seven hybridomas were selected and cloned. They were further characterized with histological immunoperoxidase assays of formaldehyde-fixed BrT paraffin tissue sections. MAb 6A3 particularly gave strong nuclear staining with all BrT specimens while MAb 1D8 showed both nuclear and cytoplasmic staining with only some of them. Specimens from mammoplasty did not react with these MAbs. Immunoblotting of BrT nuclear extracts as developed with MAbs 6A3 and 1D8 revealed major protein bands with molecular weight of 120 and 130 kDa. The potential use of these MAb-defined BrT-related nuclear proteins as markers for human breast cancer was suggested.

Cytotoxicity of respirable dusts from industrial minerals: comparison of two naturally occurring and two man-made silicates.

The membranolytic and cytotoxic properties of two naturally occurring (chrysotile asbestos; attapulgite clay) and two man-made (Fiberfrax, an aluminium-silicate, and xonotlite, a calcium silicate) industrial minerals were compared. "Short" fiber fractions of chrysotile and Fiberfrax were obtained by sedimentation in demineralized water, while the attapulgite and xonotlite samples were used as obtained. The aluminium silicate fibers were found to be non- hemolytic, while for the other three silicates, chrysotile had the strongest hemolysis potential, followed very closely by xonotlite; attapulgite was less hemolytic than the former two silicates, but was nevertheless highly hemolytic to the rat erythrocytes. Using rat pulmonary alveolar macrophages, the in vitro cytotoxicity assays showed that with fresh cell monolayers, all four silicates were equivalent in causing cell damages at a dose of 250 micrograms; at a lower dose (50 micrograms), the intensity of the cytotoxic effect was in the decreasing order: Fiberfrax greater than attapulgite greater than chrysotile greater than xonotlite. With one day-old cultured cell monolayers, a dose of 250 micrograms of the silicates fibers was less cytotoxic, with the exception of the attapulgite fibers which remained essentially as cytotoxic as with the fresh cell monolayers. The reduced cytotoxic response was especially noticeable with the chrysotile fibers. At 50 micrograms, the cytotoxicity scale of the mineral dusts with one day-old cell monolayers was essentially the same as the one obtained with the fresh cell monolayers, that is: Fiberfrax approximately equal to attapulgite greater than chrysotile greater than or equal to xonotlite. Overall, these in vitro tests imply: 1) that all four industrial silicates tested can be considered to be "biologically active"; 2) that on the basis of their different reactivities with the two types of cell culture conditions used, their biological reactivity in vivo might be quite distinct. This might be especially true for at least the chrysotile, attapulgite and xonotlite short fibers, considering that these three types of silicate dusts have very similar dimensions. Moreover, for the chrysotile and attapulgite samples, fiber numbers is probably not an important factor, since the density of the two silicates is roughly the same. The unaltered cytotoxic responses of the American attapulgite fibers in the two macrophage assays correlate well with the fact that short attapulgite fibers seems to have a stronger in vivo reactivity than short chrysotile fibers. In fact, it might be the strongest of the four industrial silicates tested.(ABSTRACT TRUNCATED AT 400 WORDS)

Oxytocin is luteolytic in the rhesus monkey (Macaca mulatta).

Oxytocin (10 mi.u./microliter/h) or vehicle (0.5% chlorobutanol in saline, 1 microliter/h) was chronically infused directly into the corpus luteum of normally cyclic rhesus monkeys, by means of an Alzet pump-ovarian cannula system. Infusion of oxytocin (N = 6) or vehicle (N = 5) began 6 days after the preovulatory oestradiol surge, and daily peripheral blood samples were taken. Oxytocin caused a significant (P less than 0.05) decrease in progesterone, beginning 1 day after treatment, and oestradiol after 4 days; progesterone and oestradiol remained significantly depressed until menstruation. However, peripheral LH concentrations remained unchanged. The duration of the luteal phase, menstrual cycle and the onset of menses from the initiation of oxytocin infusion were significantly (P less than 0.01) shorter when compared to those of vehicle-treated controls. These results show that oxytocin can induce functional luteolysis in the primate and supports the hypothesis that oxytocin of luteal origin may play a role in spontaneous luteolysis.

Cytotoxic effects of aramid fibres on rat pulmonary macrophages: comparison with chrysotile asbestos.

Aramid fibres have been proposed as a substitute for many asbestos uses. Although dimensional characteristics of aramid fibres vary with the type of application, some of the commercial grades proposed contain fibres whose geometry is clearly in a range where biological reactivities have been reported for other natural or man-made fibres. We wish to report that short aramid fibres, when tested on cultures of rat pulmonary alveolar macrophages (PAMs), induce the commonly recognized signs of a cytotoxic effect, that is: leakage of cytoplasmic and lysosomal marker enzymes, concomittant with a decreased ATP cell content.

An automated method for the determination of orotic acid in the urine of children being screened for metabolic disorders.

Urinary orotic acid is believed to be a valuable probe for early diagnosis of inborn errors of metabolism leading to hyperammonemia and increased pyrimidine synthesis. For the purpose of our urinary mass screening programme, we developed an automated colorimetric method which is reliable in the range of 1 to 50 micrograms/ml orotic acid and allows analyses at a rate of 160 samples per hour. Preliminary results are presented which illustrate that various disorders can be recognized by measuring orotic acid in urine.

Rapid thin-layer chromatographic method for the detection of urinary methylmalonic acid.

1. Simple and rapid thin-layer and micro-thin-layer chromatography techniques are described for the detection of methylmalonic acid in urine. 2. The separation of methylmalonic acid from a crude urine sample is performed by thin-layer chromatography with a mixture of silica gel-cellulose and butanol - acetic acid - water solvent system. The methylmalonic acid spot is visualized with tetrazotized o-dianisidine. 3. This system has been successfully developed for a urinary screening programme; it was shown as simple, convenient and rapid, eliminating false-positives and allowing the detection of even traces of methylmalonic acid.

Incidence and relationship of group D streptococci with other indicator organisms in meats.

Raw and processed meats were analyzed for presumptive group D streptococci using KF streptococcus agar. Counts were compared with coliform, presumptive Escherichia coli, and Enterobacteriaceae counts but no meaningful relationships were observed. Results indicated that group D streptococci and E. coli type I were principally contaminants from the packing plant, rather than at retail level. The predominating group D streptococcus in both beef and pork cuts was Streptococcus faecalis, while in processed meat (bologna), the predominating group D streptococci were Streptococcus faecium var. durans and Streptococcus faecium. Streptococcus bovis was not detected among the isolates from any meat samples. Marked differences were noted in numbers of group D streptococci in processed meat from different manufacturers. The results did not support the use of group D streptococci as alternative indicator organisms for meats. However, the association of group D streptococci with packing plant contamination may prove to be of value.

Food Poisoning Potential of Pathogens Inoculated onto Bologna in Sandwiches 1.

Bologna sandwiches inoculated separately with low levels (100 to 1000 per g) of specific pathogens at time of sandwich preparation to simulate conditions that might occur in home or food service preparation, were stored at 4, 21 and 30 C for 0, 4, 8 and 25 h and monitored for growth of pathogens. All pathogens, except Clostridium perfringens , were capable of significant growth after more than 8 h of incubation at 30 C, but not at 4 or 21 C. Significant growth at 21 C only occurred with Staphylococcus aureus after 25 h of incubation. C. perfringens failed to grow on bologna in all sandwiches. All other pathogens, except S. aureus , failed to grow on bologna with low pH (pH <6.1). Growth of S. aureus , was retarded on bologna at pH 5.5, and inhibited at pH 5.1. Only gram negative pathogens (enteropathogenic Escherichia coli and Salmonella typhimurium ) were adversely affected by increased bacterial competition. Results indicated that bologna in sandwiches under these experimental conditions would only become a potential vehicle for food poisoning under almost unrealistic conditions of handling and storage.

A Study of Microbial Quality of Vacuum Packaged, Sliced Bologna 1.

A study of 113 samples of vacuum packaged sliced bologna offered for sale in the retail marketplace revealed a wide range of total microbial loads. The pH was not closely related with age or microbial load, within the manufacturers' expected shelf-life of the product. Approximately 55% of old samples had pH >6.0, and pH was influenced by manufacturer. Confirmed coliform bacteria were detected in 5% of samples, but Escherichia coli was absent (<3/10g). In contrast, group D streptococci were present, sometimes in large numbers, depending on manufacturer. Potentially pathogenic bacteria, including Clostridium perfringens (>10/g), coagulase positive Staphylococcus aureus (>25/g) and Salmonella (in 25 g of sample) were generally not detected. Only one sample contained >25 S. aureus /g. No relationship was observed between total microbial load and indicator organisms or pathogenic bacteria.

Non-parallel response of amylase and chymotrypsinogen biosynthesis following pancreatic stimulation: a possible explanation for observed non-parallelism in pancreatic secretion.

The response of amylase and chymotrypsinogen to a pancreatic secretory stimulation (intragastric administration of oleic acid or sodium oleate) are compared in rats. This comparison concerned the rates of biosynthesis of the two enzymes, their intrapancreatic levels of storage and their rates of excretion in the juice. In each of these 3 steps, it was found that the stimulation induced non-parallel courses of amylase and chymotrypsinogen. The non-parallelism in the rates of biosynthesis was found unable to explain the entire non-parallelism observed in the rates of excretion. These results suggest that the mechanism which controls the proportions of the different enzymes in the juice is different from that which monitors the rates of individual enzymes biosynthesis.