治疗奶牛乳腺炎的新药盐酸吡利霉素研究进展

综述了治疗奶牛乳腺炎的新药——盐酸吡利霉素最新研究进展.对其基本药学性质、药动、药效、毒性和残留等多方面进行了详细阐述.     

The hemodynamic, tissue oxygenation, and selected biochemical effects of isoflurane and halothane anesthesia in horses

Eight healthy horses (337 to 643 kgs) were used to determine the effects of halothane and isoflurane (1.5 MAC) on cardiovascular and blood gas parameters over a 4 hour perio d, while in left lateral recumbency. Each animal was used twice (2 weeks apart) and the order in which the agents were used was randomized. End tidal CO2 was maintained at 45-55 mmHg using positive pressure ventilation. The following parameters were measured every 30 minutes; HR, ET CO2, ET anes. gas cone., SAP, CVP, PAP, and CO. Heparinized samples were also drawn for blood gas analysis from the right lateral metatarsal artery, right jugular vein, and the femoral veins in each rear limb. The 02 delivered to the tissues (TOD) was calculated using the following equation: {ie396-1} It was determined that more 02 was delivered to the tissues during isoflurane anesthesia (382m102/min/m2 + 21 SEM) than halothane anesthesia (280m102min/m2 + 11 SEM). Furthermore the 02 extraction ratio (OER) in the dependent limb was significantly higher during halothane anesthesia. The differences seen in the OER's are due to both anesthetic and positional effects. Serum biochemical changes also suggest differences in tissue damage related to differences in TOD and OER.     

Cardiopulmonary effects of an intravenous infusion of guaifenesin, ketamine, and xylazine in dogs

A 5% solution of dextrose in water containing 50 mg of guaifenesin, 0.25 mg of xylazine, and 1 mg of ketamine/ml was infused IV at the rate of 2.2 ml X kg-1 X hour-1 in dogs. Heart rate, systemic vascular resistance, mean arterial blood pressure, rate-pressure product, and arterial oxygen tension were not altered significantly from baseline values during 2 hours of anesthesia. Cardiac index was significantly (P less than 0.05) decreased from base-line values. Hypoventilation resulted in increased arterial carbon dioxide tension and decreased arterial pH. After the dogs were given glycopyrrolate, cardiac index returned to base line, and heart rate, mean arterial pressure, and rate-pressure product were significantly greater (P less than 0.05) than base-line values.     

Hypotension and cutaneous reactions associated with intravenous administration of etoposide in the dog

A study was undertaken to determine the pressor and toxic effects of etoposide, an antineoplastic agent, when administered IV in 0.9% sodium chloride solution (0.4 mg of etoposide/ml) over a 30-minute period to dogs at a dosage of 40 mg/m2 of body surface. On day 1, 6 adult German Shorthaired Pointers were anesthetized with halothane, and blood pressures were measured via a femoral artery catheter before, during, and after the etoposide was administered. Systolic, diastolic, and mean blood pressures of each dog decreased [corrected] significantly (P less than 0.01) within 30 minutes after initiation of etoposide infusion. On day 3, when the dogs were not anesthetized, etoposide was again administered to each dog, using the same dosage. Each dog developed a moderate to severe cutaneous reaction characterized by moderate to severe pruritus, urticaria, and swelling of the head and extremities that began during the second infusion of etoposide. These same cutaneous reactions were seen on day 30, when etoposide was administered to 3 of the previously treated dogs and 2 previously untreated Beagles. We concluded that the administration of the commercial preparation of etoposide is likely to cause a significant reduction in blood pressure of anesthetized dogs, and that the drug is likely to induce a moderate to severe cutaneous reaction when administered to unanesthetized dogs.     

Management of anesthesia in the foal

Several unique pharmacologic and physiologic factors must be considered when attempting to anesthetize premature or neonatal foals. Juvenile foals are similar to adults in their physiology and metabolism. Anesthetic drug and protocol selection should reflect the differences between these two age groups. Neonates are best anesthetized using an inhalation technique, whereas older foals can be safely anesthetized with either parenteral or inhalation anesthetic agents. Careful monitoring is absolutely essential when anesthetizing foals. The clinician should plan to routinely administer fluids and measure electrolyte levels. A basic plan and knowledge of the methods and agents used to treat hypovolemia, severe cardiopulmonary collapse, and life-threatening arrhythmias can result in survival of many critically ill foals.     

Doppler echocardiographic effects of medetomidine on dynamic left ventricular outflow tract obstruction in cats

OBJECTIVE: To evaluate the effects of medetomidine on dynamic left ventricular outflow tract (LVOT) obstruction in cats with left ventricular hypertrophy. DESIGN: Clinical trial. ANIMALS: 6 domestic shorthair cats with echocardiographic evidence of dynamic LVOT obstruction. PROCEDURE: Cats were restrained in lateral recumbency, and baseline M-mode and Doppler echocardiographic examinations were performed. An ECG was recorded continuously, and blood pressure was measured indirectly with Doppler instrumentation. Medetomidine (20 microg/kg 19.1 microg/lb]) was then administered i.m., and examinations were repeated 15 minutes later. RESULTS: Significant decreases in heart rate, LVOT velocity, and the LVOT pressure gradient were documented following medetomidine administration. After adjusting for the effects of heart rate by ANCOVA, there were no significant differences in any other systolic or diastolic indices of left ventricular function. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that administration of medetomidine to cats with dynamic LVOT obstruction may result in elimination of outflow tract obstruction; medetomidine may be a suitable sedative and analgesic agent in this subpopulation of cats.     

Cardiopulmonary responses of swine to intravenous infusion of guaifenesin, ketamine, and xylazine

Swine were anesthetized with a 5% solution of dextrose in water containing 50 mg of guaifenesin, 1 mg of ketamine, and 1 mg of xylazine X ml-1 (G-K-X) infused IV at a rate of 2.2 ml X kg-1 X hr-1. Mean arterial blood pressure and systemic vascular resistance were significantly increased from base-line values throughout the 2 hours of G-K-X infusion. Cardiac index decreased significantly initially, but returned to near base line at 30 minutes. Fifteen minutes after G-K-X infusion was discontinued, cardiac index was not significantly different from base line. Heart rate decreased significantly from base line 90 minutes after infusion of G-K-X began and remained so throughout the study. However, the mean heart rate remained within the acceptable range for swine. Rate-pressure product was not significantly altered. The PaCO2 decreased, and arterial pH increased significantly from base line, supporting our clinical impression that pigs breathe well when anesthetized with G-K-X. We conclude that G-K-X is a satisfactory combination of drugs for induction and maintenance of surgical anesthesia in healthy swine for a period of 2 hours.     

Electrical conductivity in the precambrian lithosphere of western canada

The subcrustal lithosphere underlying the southern Archean Churchill Province (ACP) in western Canada is at least one order of magnitude more electrically conductive than the lithosphere beneath adjacent Paleoproterozoic crust. The measured electrical properties of the lithosphere underlying most of the Paleoproterozoic crust can be explained by the conductivity of olivine. Mantle xenolith and geological mapping evidence indicate that the lithosphere beneath the southern ACP was substantially modified as a result of being trapped between two nearly synchronous Paleoproterozoic subduction zones. Tectonically induced metasomatism thus may have enhanced the subcrustal lithosphere conductivity of the southern ACP.