Chloramphenicol 3. Clinical pharmacology of systemic use in the horse

The use of chloramphenicol in the horse is now prohibited as horses are classified as food-producing animals. However, chloramphenicol has until recently been widely available for oral, intramuscular or intravenous administration. A critical appraisal of the published literature on the use of chloramphenicol in the horse clearly demonstrates that there are sound pharmacokinetic and microbiological reasons for concluding that chloramphenicol is not an appropriate antibiotic for systemic use. The short half-life of chloramphenicol in the horse, together with the broad range of minimum inhibitory concentrations of target pathogens, preclude the use of practical dosage regimens. It can be concluded that the withdrawal of chloramphenicol will have no adverse effects on chemotherapy in the horse.     

Evaluation of the acute phase response in cloned pigs following a lipopolysaccharide challenge

The objective of this study was to evaluate the acute phase response (APR) in cloned pigs derived from two different cell lines [C1 (n = 2) and C2 (n = 7)] as compared to genetically similar non-cloned pigs (CONT; n = 11) following a lipopolysaccharide (LPS; 25 microg/kg BW) challenge. Pigs were weaned at 21 days of age and maintained in individual pens in the same room until sample collection approximately 1 week later. Blood samples were collected every 30 min for 2 h prior to and 4h after the LPS challenge. Serum samples were analyzed for cortisol, tumor necrosis factor-alpha (TNF-alpha) and interleukin 6 (IL-6). Average gestational length for cloned pigs, 118.8 +/- 0.97 days, was longer (P < 0.005) than that of CONT pigs, 114+/-0.41 days. For serum cortisol, there was a time by group interaction (P < 0.0001) such that the cortisol response was greater in CONT pigs as compared to C2 pigs (P < 0.0001), but not different from C1 pigs (P > 0.74). A time by group interaction (P < 0.0001) was observed for serum TNF-alpha such that the TNF-alpha response was greater in CONT pigs as compared to C2 pigs (P = 0.0002) and tended to be greater (P < 0.06) than C1 pigs. A time by group interaction (P < 0.0001) was also observed for serum IL-6 such that the serum IL-6 response was greater (P < 0.003) in CONT pigs as compared to C2 pigs and there was a trend (P = 0.10) for serum IL-6 to be greater in CONT pigs compared to the C1 pigs. These are the first results to demonstrate that cortisol and proinflammatory cytokine profiles associated with the APR of cloned pigs are altered compared to genetically similar non-cloned pigs. Our results also indicate that the cell line from which clones are derived may dictate the APR. The hormone and cytokine profiles reported herein are a significant contribution towards our understanding, and perhaps our ability to prevent or reduce the incidence of premature deaths in cloned animals and warrants further investigation of the immune system of cloned animals.     

Über den Metabolismus von Endrin,Heptachlor und Telodrin

Zusammenfassung Im Rahmen der Untersuchungen über den Metabolismus insektizider Chlorkohlenwasserstoffe mit Hilfe¹⁴C-markierter Verbindungen wird über den Abbau von Endrin, Heptachlor und Telodrin in Warmblütern, Pflanzen und Mikroorganismen berichtet; die entstandenen Metaboliten wurden zum Teil als Hydroxyl-Derivate der Insektizide identifiziert.Nach oraler Applikation von radioaktiv markiertem Endrin an Ratten — Endrin weist von allen diesen Insektiziden gegenüber Warmblütern die höchste Toxizität auf — wird die Radioaktivität sehr schnell ausgeschieden (Speicherung nach 13 Tagen, bei täglicher Applikation, 14% der Gesamtaktivität; drei Tage nach letzter Endrindosis 5,3%). Als Ausscheidungsprodukte treten, hauptsächlich in den Faeces, neben geringen Mengen Endrin zwei hydrophile Metaboliten auf.20 Tage nach Besprühen von Pflanzen (Brassica oleracea) mit Endrin-¹⁴C enthalten die Wurzeln größere Mengen eines hydrophilen Metaboliten, der auch in Stengeln, Blättern und im Erdreich nachgewiesen wurde.

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Summary In the context of investigations of the metabolism of insecticidal chlorinated hydrocarbons by means of¹⁴C-labelled compounds this report deals with the degradation of endrin, heptachlor and telodrin in warm-blooded animals, plants and micro-organisms. The resulting metabolites were identified partly as hydroxyl derivatives of the insecticides.After oral application of radioactively labelled endrin in rats — endrin shows the highest toxicity among all insecticides towards warm-blooded animals — the radioactivity was very quickly eliminated (accumulation after 13 days' application was 14% of the total activity; 5,3% remained three days after the last dose of endrin). The waste products, appearing mainly in the faeces, were found to be, beside small quantities of endrin, two hydrophilic metabolites.20 days after plants(Brassica oleracea) were sprayed with endrin-¹⁴C the roots contained considerable amounts of a hydrophilous metabolite. The latter was also found in stems, leaves and in the soil.

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Resumé Dans le cadre de recherches sur le métabolisme des insecticides à base d'hydrocarbures chlorés, effectuées à l'aide de composés marqués à¹⁴C, on expose les modalités de dégradation de l'endrine, de l'heptachlore et de la télodrine chez les animaux à sang chaud, chez les plantes et les micro-organismes; on a identifié une partie des métabolites obtenus comme dérivés hydroxyles des insecticides.Après l'administration par voie buccale à des rats d'endrine marquée, qui a, de tous ces insecticides, la plus grande toxicité pour les animaux à sang chaud, la radioactivité était très vite éliminée. L'activité résiduelle totale était de 14% après qu'on leur avait administré une dose quotidienne d'endrine pendant 13 jours et de 5,3% trois jours après la dernière administration. Parmi les produits éliminés, surtout dans les fèces, il faut citer, à côté de quantités réduites d'endrine, deux métabolites hydrophiles.20 jours après la pulvérisation des plantes(Brassica oleracea L) avec de l'endrine-¹⁴C, les racines contenaient des quantités appréciables d'un métabolite hydrophile, que l'on a aussi détecté dans les tiges, les feuilles et le sol.

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mit 11 Fig.     

Are Pesticides Suitable Model Substances for the Evaluation of Industrial Chemicals in the Environment?

Definitions are given for the terms «environmental chemical>> and «undue persistence>>. A suggested model for the general evaluation of environmental chemicals is a balanced combination of the evaluations of environmental radioactivity and of pesticides. The classification of environmental chemicals should be based on chemical structures only, independent of use patterns. For the evaluation of any chemical, the knowledge of its total production and of the quantitative use pattern is indispensable.     

Antagonism of detomidine with tolazoline in isoflurane-anaesthetised ponies

The effects of tolazoline (4.0 mg/kg iv) antagonism of detomidine (0.02 mg/kg iv) were evaluated in isoflurane-anaesthetised, ventilated ponies. Each of 6 ponies received both tolazoline and saline treatment during separate anaesthetic episodes only (no surgery was performed). Detomidine administration produced an increase in blood pressure, decrease in heart rate and decrease in P_aO₂ Tolazoline treatment transiently increased heart rate while blood pressure returned to baseline after both treatments. Arterial oxygenation decreased further after tolazoline treatment while oxgenation recovered towards baseline with saline treatment. No other cardiopulmonary effects were detected. Recovery from anaesthesia tended to be more rapid when detomidine was antagonized. The potential benefit of antagonizing detomidine-induced bradycardia with tolazoline, during isoflurane anaesthesia should be weighed against the potential to produce a decrease in arterial oxygenation. The mechanism for this effect is not clear.     

Viral diseases of the rabbit.

Viral disease in the rabbit is encountered infrequently by the clinical practitioner; however, several viral diseases were reported to occur in this species. Viral diseases that are described in the rabbit primarily may affect the integument, gastrointestinal tract or, central nervous system or maybe multi-systemic in nature. Rabbit viral diseases range from oral papillomatosis, with benign clinical signs, to rabbit hemorrhagic disease and myxomatosis, which may result in significant clinical disease and mortality. The wild rabbit may serve as a reservoir for disease transmission for many of these viral agents. In general, treatment of viral disease in the rabbit is supportive in nature.