American journal of veterinary research
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Comparative Study
Comparison of capillary ear blood and arterial blood to validate capillary sampling as an accurate assay of blood gas in swine.
Capillary sampling in swine can be performed as an accurate assay of arterial blood gases. Studies with swine provided results similar to, or slightly more favorable than, those reported for human beings, depending upon which cutaneous technique was used on human beings. On the basis of free flow or arterilization of the cutaneous sample and of the correlation between capillary and arterial pH, CO2 partial pressure (PCO2), and O2 partial pressure (PO2) values, the capillary sampling technique of complete incisement of a 2-mm section from the tip of the warmed porcine ear could be a substitution technique for arterial blood sampling. Free flow with this technique was maximized and high correlation coefficients (r) for pH (r = 0.96), PCO2 (r = 0.82), and PO2 (r = 0.90) capillary-arterial values (n = 37) were obtained.
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Comparative Study
Actions of oxytocin and a long-acting carba oxytocin analog on the porcine myometrium in vitro and in vivo.
The contractile actions of oxytocin and its analog 1-desamino-1-monocarba-[2-Tyr(OMe)]-oxytocin were compared on in vitro (experiment 1) and in vivo (experiment 2) preparations of porcine uterine horns. In both experiments, sows in estrus were selected for maximal sensitivity. Despite the loss of peak amplitude associated with the substitution at sequence position 2 of O-methyltyrosine for tyrosine, the two remaining alterations (N-terminal desamination and replacement of the 1-6 S-S bridge by CH2S) prolonged the action of single-dose presentations. Thus, instead of having a response lasting minutes when the parent hormone is given, an IV dose of about 5 micrograms of the analog/kg of body weight in the intact anesthetized sow resulted in a response lasting two hours.
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The long-acting oxytocin (OT) analog 1-desamino-1-monocarba-E12-Tyr(OMe)]-OT(dCOMOT) was given IV to 13 pregnant cows near to term, but not in actual labor. The animals were para 1 to 5. Of these cows, four were treated with 20 mg of dexamethoasone 48 hours before the peptide was injected; the remaining nine animals were given no other medication. ⋯ The difference between the two values was significant. For both groups separately, and all data together, there was a linear inverse relation between the size of the external ostium uteri at injection and the duration of labor after peptide injection. All calves were healthy with no signs of hypoxia and the dose rates used did not result in any instance of uterine tetany or tachyphylaxis.
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Intranasal and intraperitoneal exposure of English ferrets (Mustela putorius furo L) to infectious bovine rhinotracheitis virus caused acute and chronic infections of the respiratory tract. The clinical syndrome was characterized by sneezing, coughing, and anorexia from postexposure days (PED) 3 to 7. Mucopurulent exudate was observed in the posterior nares and pharyngeal area of ferrets euthanatized on PED 4 and 8. ⋯ Recrudescence of chronic infection could be elicited by daily intraperitoneal injections of 4.0 mg of dexamethasone. However, daily administration of 2.0 mg of dexamethasone intraperitoneally did not cause more severe clinical disease. Results of serologic studies revealed serum antibody profiles comparable with those expected in experimentally exposed cattle.
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Comparative Study
Potency of enflurane in dogs: comparison with halothane and isoflurane.
Circulatory and respiratory responses to graded increases in alveolar concentrations of enflurane were investigated in unpremedicated healthy dogs during conditions of spontaneous and controlled ventilation. The minimal alveolar concentration (MAC) of enflurane that prevented movement in response to a standard painful stimulus was determined for each dog and averaged 2.06 vol%. ⋯ The average end-tidal enflurane concentration that produced at least 60 s of apnea was 5.29 vol% (ie, MAC 2.57). A comparison of these data with previous studies in dogs indicates that equipotent concentrations of enflurane are at least as depressant to the cardiopulmonary system as halothane and isoflurane.