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Biomedical subjects

M Wanner

Publications and source records attributed to M Wanner.

At least 91 records · Page 5Linked to original sources
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

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↗
PubMed1981

Cell-mediated and humoral immune response in swine after vaccination and natural infection with Mycoplasma hyopneumoniae.

Litters of pigs were vaccinated with inactivated Mycoplasma hyopneumoniae organisms in Freund's complete adjuvant. The cell-mediated and humoral immune response following vaccination was investigated, and the protective effect of the induced immunity was assayed. The cell-mediated immune response to whole M hyopneumoniae organisms was determined as incorporation of tritiated thymidine, using a microculture system. After vaccination, detectable sensitization of peripheral blood lymphocytes was induced. The inoculations induced considerable antibody titers in the animals. The animals were challenged exposed by natural infection and protective effect of the cell-mediated or humoral response could not be detected.

Animals↗
PubMed1979

Serum lipids in swine fed large quantities of whey.

The causal relationship between hyperlipidemia and atherosclerotic diseases is undoubted. But studies of the last years have shown that this relationship is quite complex and may be even controversial. A food which has recently been placed in the foreground in lipid metabolism research is milk and its products. By accidental findings it was shown that the more milk was drunk, the lower the serum cholesterol concentration became. This brought about some controlled feeding studies on animals and humans. We chose swine for our feeding study because of their resemblance to human lipid metabolism. 57% of the whole energy consumed consisted of whey powder fed in a crossover study lasting 112 days. The results show that total cholesterol was significantly lower during whey feeding. The lipid decrease also included the HDL-fraction and, to a lesser degree, triglycerides. It seems well enough proved to be an accepted fact that the relative high content of saturated fatty aids in milk is cancelled by a substance present in milk and some of its products such as whey. Further investigations to study this milk factor in more detail including the application of high fat diets will be done.

Animal Feed↗
PubMed1977

Farmer's lung: immunological response to a group of extracellular enzymes of Micropolyspora faeni. An experimental and field study.

Potent immunogenicity of certain extracellular 'chymotrypsin-like' enzymes of Micropolyspora faeni are demonstrated. One of them, Enzyme 1 seems particularly active in stimulating the formation of percipitins after intratracheal exposure in rabbits. Man or cattle exposed naturally to mouldy hay, either with or without clinical farmer's lung symptoms show a rather constant immunological reaction against Enzyme 1 and partly also against others of the same group. The detection of specific percipitins against these enzymes is not likely to improve the diagnostic value of the standard farmer's lung serology. Possible implications of these proteolytic enzymes in the pathogenesis of farmer's lung are discussed.

Animals↗