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Biomedical subjects

J Nicolet

Publications and source records attributed to J Nicolet.

At least 163 records · Page 9Linked to original sources
PubMed1982

[Multicenter study on the status of antibiotic and chemotherapy resistance in Switzerland 1979].

In 1979 a three-month multicentre study of resistance of bacteria isolated from humans and animals was carried out in Switzerland with the participation of 22 institutes and laboratories. A total of 23,852 antibiograms were evaluated concerning the following bacteria: Escherichia coi, Klebsiella pneumoniae, Salmonella sp., Serratia marcescens, Proteus (indole-negative), Proteus (indole-positive), Pseudomonas aeruginosa, Staphylococcus aureus, and enterococci (streptococci of Group D). 95.5% of the strains were isolated from human material, almost half being isolated from urine. The remaining 4.5% were obtained from animal material, more than half being isolated from the milk of cows with mastitis. Although the various institutes and laboratories did not use a uniform, standardized method, the results are closely in line with those of similar studies carried out earlier in Switzerland, Germany, Austria and the USA. No pronounced trend in the direction of increased resistance is observable.

Animals↗
PubMed1982

Pharmacokinetics of oxytetracycline and therapeutic implications in veal calves.

Pharmacokinetic parameters of oxytetracycline were analysed in healthy preruminant veal calves after intravenous, intramuscular and oral administration. The serum half-lives in the beta-elimination phase of both 10% and 20% solutions after i.v. injection of 10 mg/kg were similar (7.07 +/- 1.36 h and 7.16 +/- 1.17 h, mean +/- SD), whereas the total body clearance and the apparent volume of distribution were higher for the 20% solution. Serum concentrations above 0.5 microgram/ml were maintained with both formulations during 12-24 h but were only above 4 micrograms/ml to 5 h. Intramuscular administration of the 20% solution gave a complete absorption with two rate constants of absorption, a faster (t1/2 alpha 1 = 0.27 h) and a slower one (t1/2 alpha 2 = 10.90 h) responsible for the delayed elimination half-life after this route of application (t1/2 beta = 9.83 +/- 1.35 h). Mean serum concentrations reached a maximum level of 3.01 +/- 0.72 micrograms/ml at 4.01 +/- 2.84 h and decreased to 0.5 microgram/ml between 12 and 24 h. 50 mg/kg given orally with a milk replacer were found to have a mean bioavailability of 46.35%. A mean serum peak level of 4.99 +/- 1.37 micrograms/ml was achieved at 9.16 +/- 1.99 h and the mean concentration was still above 0.5 microgram/ml after 48 h. The elimination half-life (t1/2 beta = 10.66 +/- 3.15 h) reflected the slow absorption step (t1/2 alpha 2 = 10.15 h) following that responsible for the initial faster absorption (t1/2 alpha 1 = 1.99 h). Comparison of the area under the serum curves gave mean values of 117% for tetracycline and of 53% for chlortetracycline relative to oxytetracycline (arbitrarily fixed at 100%) after identical oral dosage of the three tetracyclines. We also propose and discuss a dosage schedule based on minimal inhibitory concentrations of different susceptible pathogens.

Administration, Oral↗
PubMed1982

Distribution of penicillin G, dihydrostreptomycin, oxytetracycline, and chloramphenicol in serum and subcutaneous chamber fluid.

Penetration of penicillin G, dihydrostreptomycin, oxytetracycline, and chloramphenicol into interstitial fluid of calves was estimated using subcutaneously implanted, multiple perforated spherical polypropylene capsules as a model. Antibiotic concentrations were determined in simultaneously withdrawn serum and capsular fluid (CF) samples at intervals after single and multiple intramuscular injections of antibiotics at recommended dose schedules. Peak concentrations of penicillin G in CF were 57% of those in serum, and the drug was eliminated from CF at a slower rate than from serum. Dihydrostreptomycin diffused into CF to a limited degree and was eliminated from CF much more slowly than from serum leading to gradual drug accumulation in CF upon repeated dosing. Multiple injections of oxytetracycline resulted in CF drug levels comparable with those in serum. Concentrations of chloramphenicol in CF were generally similar to free (non-protein bound) serum drug levels. CF concentrations of penicillin G were within the range of the minimal inhibitory concentrations of the drug for pathogenic gram positive micro-organisms and CF levels of dihydrostreptomycin, oxytetracycline, and chloramphenicol were apparently sufficient to inhibit the majority of gram negative pathogens involved in bovine injections. Advantages and limitations of the tissue cage model are briefly discussed.

Animals↗
PubMed1982

Protection against colibacillosis in neonatal piglets by immunization of dams with procholeragenoid.

Protection against colibacillosis in neonatal piglets was obtained by immunization of pregnant dams with procholeragenoid. Procholeragenoid is a stable high-molecular-weight aggregate of cholera toxin formed during the heating of cholera toxin. Procholeragenoid retained approximately 1% of the toxicity of native toxin as determined in the rabbit ileal loop and Y-1 adrenal cell assays and 5% of the activity in the rabbit skin assay. Immunization of pregnant dams with 50 micrograms of procholeragenoid 5 and 2 weeks before the expected delivery date elicited high titers of antitoxic immunoglobulin G and toxin-neutralizing antibody in both the colostrum and serum. In three independent field trials, immunization with procholeragenoid resulted in a substantial decrease in diarrhea (73% in controls versus 11% in immunized) and death (4.7% in controls versus 0.77% in immunized) in neonatal piglets. The protection rate in the immunized population was approximately 85% for both diarrhea and death. In the following gestation period, reimmunization of dams with a single dose of procholeragenoid (50 micrograms) 2 weeks before delivery elicited titers of antitoxic immunoglobulin G and toxin-neutralizing antibody comparable to those obtained during the primary immunization. The death rate in neonatal piglets (0.86%) was comparable to that seen after immunization during the first gestation period (0.77%). These results indicate that substantial protection of neonatal piglets against colibacillosis can be obtained by immunization of dams with procholeragenoid. Protection was found to be based solely on antitoxic immunity.

Animals↗
PubMed1981

An enzyme-linked immunosorbent assay, using an EDTA-extracted antigen for the serology of Haemophilus pleuropneumoniae.

An enzyme-linked immunosorbent assay (ELISA) was proposed as an alternative to the complement-fixation test (CF) for the detection of antibodies of Haemophilus pleuropneumoniae, agent of the pleuropneumonia in pigs. In tests done with different antigen-extraction procedures (including Tween 20, sodium dodecyl sulfate, aqueous phenol, sonification, and heat treatment at 120 C), ethylenediaminetetraacetic acid (EDTA) provided a satisfactorily reactive antigen. Chromatography purification on Sephacryl S200 improved the specificity of this antigen. Using hyperimmune rabbit sera, we investigated the specificity and the sensitivity of the ELISA with the EDTA-purified antigen of the different serotypes of H pleuropneumoniae on selected swine sera in herds with confirmed H pleuropneumoniae infection, from specific-pathogen-free animals showing doubtful CF reactions. The ELISA proved to be highly specific and more sensitive than the CF test. Furthermore, evidence of cross-reactions with H parasuis, a common bacteria isolated in swine populations, was not found.

Animals↗
PubMed1981

Experiments with the double isotope single-injection method for determining glomerular filtration rate and effective renal plasma flow in veal calves.

Single injections of the radiochemicals Cr51-EDTA and I125-ortho-iodohippurate (I125-OH) were used simultaneously to measure the glomerular filtration rate (GFR) and effective renal plasma flow (ERPF), respectively, in 26 calves weighing between 37 kg and 90 kg. The mean GFR was 2.31 ml per minute per kg and the mean ERPF was 9.62 ml per minute per kg. These values are very similar to the GFR and ERPF measured in young calves and adult cattle by using constant infusions of inulin and para-aminohippurate as marker substances. Correlation coefficients of the order of 0.70 were found between clearance values and body-weights. The method described is rapid and reliable.

Animals↗