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Biomedical subjects

R H Teske

Publications and source records attributed to R H Teske.

At least 19 recordsLinked to original sources
PubMed1986

Legal implications of the extra-label use of drugs in food animals.

Although the Food and Drug Administration has never sanctioned the extra-label use of drugs in animals, it has not, until recently, objected when veterinarians deviated from label instructions as long as such use did not result in violative residues in food products derived from treated animals. However, because of the potential human health hazards associated with abuse of this position, the FDA has developed a less lenient policy toward the extra-label use of drugs in food animals. A brief review of the legislated responsibility and authority of the FDA with particular reference to the extra-label use of drugs in food animals is provided. Emphasis is placed on how anesthetics and anesthesia adjuncts in food animals can pose human health hazards.

Adjuvants, Anesthesia↗
PubMed1983

Disposition of ampicillin administered intravenously and intratracheally to young calves.

The profile of the blood concentration of ampicillin vs time was compared in 24 calves after ampicillin administration (10 mg/kg body weight) by the intratracheal (i.t.) and the intravenous (i.v.) routes in a crossover study. In a subsequent study, 12 of the calves were given ampicillin i.v. and 12 were given ampicillin i.t.; at 15 min and 2 h after drug administration, the calves were killed and lungs, kidneys, liver, urine and plasma were collected for ampicillin assay. The mean ampicillin concentration in blood after i.v. treatment was significantly (P less than 0.01) higher than after i.t. treatment. The mean ampicillin level in lungs after i.t. treatment was significantly higher than the level after i.v. treatment, but concentrations in kidneys, liver, urine and plasma after i.v. treatment were higher (but not significantly) than those after i.t. treatment.

Ampicillin↗
PubMed1979

Pharmacokinetic study of sulfadimethoxine depletion in suckling and growing pigs.

Sulfadimethoxine was administered (IV) to suckling pigs (1 to 2 weeks old) and to growing pigs (11 to 12 weeks old) at a dosage of 55 mg/kg of body weight (single dose). Blood samples were collected over a 48-hour period, and the animals euthanatized were used for measurements of plasma and tissue concentrations of the drug. The blood data were described, using a one-compartment pharmacokinetic model. The blood concentration curves for the two groups of pigs had a consistent depletion pattern with greater than therapeutic concentrations (50 micrograms/ml) of the drug persisting through 12 hours after the drug was given. Sulfonamide blood concentrations were 4 and 11 times that of the method sensitivities in the older (growing) and younger (suckling) pigs, respectively, at 48 hours after treatment. In four of the five pharmacokinetic variables studied, a significantly higher (P less than 0.01) degree of efficiency was observed in the ability of the older pigs to eliminate the drug than in the younger pigs.

Animals↗
PubMed1979

Use of the double-isotope single-injection method for estimating renal function in normal cross-bred swine.

The double-isotope single-injection method to estimate renal function which utilizes the radiolabeled chemicals [131I]sodium iodohippurate and [125I]sodium iothalamate was evaluated in swine. A total of 46 normal, cross-bred swine were used to determine the applicability of this method for measuring the glomerular filtration rate and effective renal plasma flow. The mean glomerular filtration rate in pigs was determined to be 5.33 +/- 0.82 ml/kg of body weight/minute for [125I]sodium iothalamate with a biological half-life (T 1/2) of 39.18 +/- 7.44 minutes. The mean effective renal plasma flow was determined to be 19.25 +/- 3.12 ml/kg of body weight/minute for [313I]sodium iodohippurate, with a T 1/2 of 18.45 +/- 1.74 minutes. These values are more closely related to the glomerular filtration and effective renal plasma flow values reported for dogs and cats than they are to values reported for man. The method is rapid and reliable; results are available 6 to 8 hours after the experiment. This method is advantageous when information about renal function variables is a prerequisite to pharmacokinetic or toxicologic studies.

Animals↗
PubMed1977

Tissue distribution of PCB components in swine and sheep fed three different rations containing Aroclors 1242 and 1254.

Growing swine and sheep were fed three dietary variations containing 20 ppm of Aroclors 1242 or 1254 for 13 to 15 weeks. Generally, Aroclor 1254 residues were higher; higher 1242 residues in swine blood, spleen, and ovary are attributed to persistent major components of this Aroclors. Some minor differences in total PCB were observed with varying diets, but peak composition did not vary. Some lower chlorinated components maintained higher levels in the blood relative to other components; other components were selectively accumulated in tissues such as fat and muscle. Blood and fat residues in sheep declined during the last weeks of feeding. Microsomal oxidase levels were elevated in response to PCB and diet in both species, but the response was greater in sheep. Sheep liver microsomes were capable of metabolizing pure analogs and components of Aroclor 1242. Major differences in Aroclor profiles can be demonstrated between swine and sheep residues and total residues can be estimated by measuring selected peaks in blood and backfat. The peaks which provide the most reliable estimate of total PCB residue vary with species and Aroclor.

Animal Feed↗
PubMed1977

Effect of storage on bovine erythrocyte cholinesterase activity.

Bovine whole blood and washed erythrocyte samples with either sodium heparin or EDTA as the anticoagulant were stored at -24, 2 to 3, 21, or 37 C for up to 8 weeks to determine the stability of erythrocyte cholinesterase (ChE) activity. An automated colorimetric method was used to measure ChE activity. Regression analysis was used to estimate the rate of decline of ChE activity of samples to 95% of normal. Samples stored at -24 and 2 to 3 C were very stable, and ChE activity was maintained for several weeks or longer. Samples stored at 21 C maintained an activity level not less than 95% of normal for at least 9 days and those stored at 37 C for at least 2 days. The type of anticoagulant used did not appear to affect significantly the stability of activity.

Animals↗
PubMed1976

Apparent pharmacokinetics of PCB components in growing pigs and lambs when fed a ration containing Aroclor 1254.

Young growing lambs and pigs were fed a ration containing 200 ppm of Aroclor 1254 for 35 days and then switched to "clean" feed. Blood and fat samples were collected periodically throughout the experiment and analyzed for components of Aroclor 1254 and total PCB. Several components are apparently accumulated and eliminated at different rates within each species, as seen by comparing gas chromatograph tracings, accumulation ratios and apparent rate constants of elimination. Differences in accumulation and elimination of Aroclor components, some of which were apparently caused by differences in growth rates, were also seen between pigs and lambs. Variable growth rates of different species of food producing animals are an important factor to consider when dealing with tissue distribution and residues of polychlorinated biphenyls for determination of carcass disposition, as well as accumulation of toxic concentrations in the animal body.

Adipose Tissue↗