Disposition of sulfonamides in food-producing animals: pharmacokinetics of sulfamerazine in cattle

The disposition of sulfamerazine in the plasma and urine of cattle was determined following single intravenous and oral doses. The averaged and the individual animal data were described by a two-compartment pharmacokinetic model. The drug was eliminated with a biological half-life of 6.2 h, primarily by renal excretion of unchanged sulfamerazine and metabolism to acetylsulfamerazine. Sulfamerazine (in solution) was absorbed with a half-life 6.7 h and with relative completeness (68%) following oral administration.     

Effect of Desmopressin Acetate on Bleeding Times and Plasma von Willebrand Factor in Doberman Pinscher Dogs with von Willebrand''s Disease

Effects of desmopressin acetate (1-desamino-8-D-arginine vasopressin [DDAVP]) on plasma von Willebrand factor (vWf) were studied in 12 purebred Doberman pinschers confirmed to have von Willebrand's disease (vWd) (plasma vWf antigen [vWf:Ag] concentrations, less than 30 U/dl). Twelve dogs had subnormal plasma botrocetin cofactor (BCf) activity and 11 dogs had prolonged buccal mucosa bleeding times. Tranquilization of three dogs with lenperone and three dogs with xylazine did not induce significant changes in mean plasma vWf:Ag concentrations or mean BCf activities. Thirty and 120 minutes after administration of DDAVP (1 micrograms/kg subcutaneously), there was significant shortening of the mean buccal mucosa bleeding time. Ten dogs responded to DDAVP with increases in BCf activity which exceeded 10 U/dl at 30 or 120 minutes, or both, after the drug was administered. At the same time, increases in plasma vWf:Ag concentrations were smaller than the increases in BCf activity. It was shown by multimeric analysis that primarily the higher molecular weight forms of vWf increased in plasma in response to DDAVP.     

Hemodynamic Changes During Laparoscopic Radiofrequency Ablation of Normal Adrenal Tissue in Dogs

Objective— To determine the hemodynamic response to radiofrequency ablation (RFA) of normal adrenal tissue in dogs.
Study Design— Experimental study.
Animals— Healthy adult mixed-breed dogs (n=6).
Methods— During general anesthesia a Swan–Ganz thermodilution catheter was flow directed into the pulmonary artery and used to quantify cardiac output. An arterial catheter was used for direct blood pressure measurements. An RFA device was introduced into the left adrenal gland under observation through laparoscopic instrumentation. Blood samples were collected and hemodynamic variables studied after a stable surgical anesthetic depth was achieved (time 1), during CO₂ insufflation of the abdomen (time 2), during adrenal RFA (time 3), and after completed RFA (time 4). Catecholamine determinations were performed with a human enzyme immunoassay. Histopathology was performed to verify medullary necrosis.
Results— Arterial, pulmonary arterial and central venous pressure, and plasma norepinephrine increased more during RFA than during abdominal insufflation. Heart rate and cardiac index did not differ between time points. High baseline epinephrine was present and significant differences between time points were not detected. Systemic vascular resistance had very high individual variation and differences were not detected.
Conclusions— RFA of normal adrenal tissues is associated with severe hemodynamic alterations. Further studies of the optimal blockage of catecholamine-induced hypertension in dogs are warranted.
Clinical Relevance— Clinicians should prepare for potential hypertensive crisis during RFA of adrenal masses, especially if treating a margin of normal tissue.     

Disposition of sulphonamides in food-producing animals: disposition of sulphathiazole in tissues, urine, and plasma of cattle following intravenous administration

Plasma, urine and tissue concentrations of sulphathiazole were determined at various times following intravenous administration to fifteen cattle. The averaged plasma and urine data were consistent with a two-compartment pharmacokinetic model with a half-life of elimination of 1.3 h and a total volume of distribution of 0.41 l/kg body weight. Sulphathiazole was eliminated by excretion of unchanged drug into urine (48%) and by formation of acetylated and polar metabolites. The averaged data obtained from eight selected tissue sites were consistent with the two-compartment pharmacokinetic model presented and confirmed that residues of sulphathiazole in edible tissue can be predicted from serum and urine concentrations of the drug.     

Acute Gastrointestinal Disease in 27 New World Camelids: Clinical and Surgical Findings

Objective—To describe clinical and surgical findings from New World camelids with acute gastrointestinal disease.
Study Design—Retrospective study.
Animal Population—20 llamas and 7 alpacas.
Methods—Camelids were grouped based on surgical lesions. Clinical and surgical findings were compared between groups and between surviving and nonsurviving camelids.
Results—Twelve of 27 initial celiotomies and 3 of 4 repeat celiotomies were successful. Death occurred from euthanasia during surgery (nine camelids), peritonitis or sepsis (five), aspiration pneumonia (one), and respiratory distress (one). Survival was lowest after celiotomy for proximal obstruction (3 of 10 camelids), ruptured viscus (0 of 4), and necrotizing enteritis (0 of 2) and highest after celiotomy for distal obstruction (10 of 13) and septic peritonitis without ruptured viscus (2 of 2). Before surgery, camelids with proximal obstruction had significantly lower ( P < .05) serum chloride concentrations (median, 97 mEq/L) than those with distal obstruction (median, 109 mEq/L) or ruptured viscus (median, 117 mEq/L). Serum bicarbonate concentration also was highest (median, 34.6 mEq/L) and often greater than 28 mEq/L in camelids with proximal obstruction. Camelids with distal obstruction had significantly lower ( P < .05) nucleated cell counts in peritoneal fluid (median, 700 cells/μL) than those with ruptured viscus (median, 20,600 cells/μL) or septic peritonitis (median, 88,300 cells/μL).
Conclusions—Camelids with proximal obstruction often had hypochloremic metabolic alkalosis. Camelids with distal obstruction had less metabolic derangement and tissue compromise and a higher survival rate.
Clinical Relevance—Awareness of the characteristics of the various types of acute gastrointestinal disease in camelids will augment veterinarians' ability to diagnose and treat these disorders.     

Sutured End-to-End and Stapled Side-to-Side Jejunal Anastomoses in the Horse

Hand sutured end-to-end (EE) and stapled side-to-side (SS) small intestinal anastomoses were performed in 10 healthy adult horses. In five SS anastomoses, staple lines on the blind ends of the jejunum were inverted (SSI) and in five they were not (SSNI). Five EE anastomoses were sutured with polydioxanone and five were sutured with polyglyconate. All horses were euthanatized on day 30. Intra-abdominal adhesions were graded (0-4), and stomal areas were calculated from contrast radiographs made with the bowel distended. Histopathology scores for the anastomoses were based on the degree of inflammation (0-3), fibrosis (0-3), and alignment and healing of intestinal layers (0-3). Mean surgery times +/- standard deviations for EE, SSI, and SSNI techniques were 33.9 +/- 5.4, 36.2 +/- 5.6, and 29.6 +/- 5.9 minutes, respectively. Mean and median stomal areas were 9.4 +/- 5.5 and 8.9 cm2 for EE anastomoses and 17.2 +/- 16.5 and 12.1 cm2 for SS anastomoses. Intra-abdominal adhesions developed in three horses, one of which had clinical signs of colic. Mean histopathology scores for EE and SS anastomoses were 4.8 +/- 2.0 (median = 5) and 4.4 +/- 1.8 (median = 4), respectively. There were no statistically significant differences in surgery times, intra-abdominal adhesion scores, stomal areas, or histopathology scores between small intestinal EE and SS anastomoses in these horses.     

Effects of disease and plant competition on yield in monocultures and mixtures of two wheat cultivars

Disease seventy and crop yield were compared in monocultures and mixtures of two wheat cultivars. one susceptible and one resistant to Puccinia graminis f. sp. tritici. Part of each plot was inoculated and part treated with fungicide. Rust seventy was inversely related to the proportion of resistant plants present. Weight of grain in 100 heads of the susceptible cultivar increased as the amount of rust decreased. The susceptible cultivar yielded less than the resistant cultivar in monoculture, but was a stronger competitor in mixtures. Competitive abilities of the cultivars were independent of severity of rust in the mixtures studied.     

Tonometry in the Dog and Cat

Abstract— A review is presented of the methods, procedure and value of the use of tonometry in the dog and cat.
Résumé— L'auteur passe en revue les méthodes, les techniques et la valeur de l'emploi de la tonométric chez le chien et le chat.
Zusammenfassung— Es wird eine Übersicht über die Methoden, das Verfahren und die Bedeutung der Tonometrie bie Hund und Katze gegeben.