Effects of Acute Hyperventilation on Serum Potassium in the Dog

The effects of increasing respiratory rates on arterial pH, PaCO2, HCO3, and potassium (K) were measured in normal anesthetized dogs. Hyperventilation resulted in increased pH, decreased PaCO2, decreased HCO3, and decreased K compared with those parameters in spontaneously breathing dogs. The changes were related quantitatively: each 10 mmHg decrease in PaCO2 was associated with a pH increase of 0.1, a HCO3 decrease of 2.0 mEq/L, and a K decrease of 0.4 mEq/L. There were no cardiac arrhythmias or clinical signs of hypokalemia. After termination of hyperventilation, serum K was slower to return to control values than PaCO2. The ratio of the duration of hyperventilation to the time required for return of serum K to control was 0.67.     

Vulvovaginectomy and Perineal Urethrostomy for Neoplasms of the Vulva and Vagina

Vulvovaginectomy and perineal urethrostomy were performed in three dogs with extensive neoplasms of the vulva and vagina. One benign tumor (fibroleiomyoma) and two malignant tumors (transitional cell carcinoma and anaplastic spindle cell sarcoma) were diagnosed. Survival times were 9 weeks to 10 months. Urinary continence was preserved in all three dogs. The procedure may be curative for benign tumors or malignant tumors that have not yet metastasized; it is a palliative procedure for advanced malignancies.     

Upper Airway Function during Maximal Exercise in Horses with Obstructive Upper Airway Lesions Effect of Surgical Treatment

Upper airway pressure was measured during maximal exercise in 10 Thoroughbred racehorses with naturally occurring upper airway obstruction. Left laryngeal hemiplegia and arytenoid chondropathy resulted in substantial increases (30-40 cm H2O) in inspiratory upper airway pressure (Pl), whereas complicated aryepiglottic entrapment and subepiglottic cysts produced only modest increases (15 cm H2O) in Pl. Uncomplicated aryepiglottic entrapment and grade IV pharyngeal lymphoid hyperplasia produced only slight increases (3-5 cm H2O). In general, surgical procedures restored airway pressures to within normal limits. Subtotal arytenoidectomy improved but did not normalize airway pressures in horses with arytenoid chondropathy. Pharyngeal lymphoid hyperplasia appeared to have little effect on upper airway function.     

Ventricular Septal Defect Repair

Twelve dogs and one cat were operated to close a ventricular septal defect. The method of patient selection, associated lesions, techniques used to correct the defect and significance to the total population of small animals with congenital lesions is discussed. Ten of 13 animals survived surgery. When indicated, this procedure can be safely performed to correct ventricular septal defect.     

Idiopathic Sterile Granulomatous and Pyogranulomatous Dermatitis in Cats

Abstract— Idiopathic sterile granulomatous or pyogranulomatous dermatitis was diagnosed in four cats. Two distinct clinicopathological syndromes were recognized. Two cats had a pruritic papulonodular dermatitis of the head and pinnae with skin histopathology characterised by perifollicular pyogranulomatous dermatitis. The other two cats had pruritic bilateral preauricular plaques characterised histopathologically by diffuse granulomatous dermatitis with numerous multinucleated histiocytic giant cells and purpura. Haematological, biochemical and urinary abnormalities were not detected and the cats were otherwise healthy. Lesions were not responsive to systemic antibiotics or systemic glucocorticoids at anti-inflammatory doses. Three cats underwent apparently spontaneous, sustained remission after a course of 3 to 9 months. Résumé— Une dermatite granulomateuse idiopathique stérile, ou pyogranulomateuse fut diagnostiquée chez 4 chats. Deux syndromes distincts ont été identifiés. Deux chats avaient une dermatite papulonodulaire prurigineuse de la tête et des oreilles, avec des biopsies cutanées caractérisées par une dermatite pyogranulomateuse périfolliculaire. Les 2 autres chats avaient des plaques prurigineuses préauriculaires bilatérales, caractérisées histologiquement par une dermatite granulomateuse diffuse avec de nombreuses cellules géantes multinucléées et du purpura. Les examens hématologique, biochimique et urinaire étaient par ailleurs normaux et les chats en bon état général. Les antibiotiques et les corticoides à dose antiinflammatoire, tous deux par voie générale, sont restés sans effet. Trois chats ont présenté une rémission spontanée après une évolution de 3 à 9 mois. Zausammenfassung— Bei vier Katzan wurde eine idiopathische sterile granulomatöse oder pyogranulomatöse Dermatitis diagnostiziert. Dabei konnten zwei klinisch-pathologisch abgrenzbare Syndrome erkannt werden. Zwei Katzen wiesen eine pruriginöse, papulo-noduläre Dermatitis am Kopf und an den Ohren auf, wobei histologisch eine perifollikuläre pyogranulomatöse Dermatitis festgestellt wurde. Die beiden anderen Katzen zeigten pruriginöse, bilaterale präaurikuläre Plaques, deron histologisches Bild durch eine diffuse granulomatöse Dermatitis mit zahlreichen vielkernigen histiozytären Riesenzellen und Purpure gekennzeichnet war. Abnormalitäten bezüglich hämatologischer, biochemischer und harnspezifischer Parameter wurden nicht festgestellt, auch waren die Katzen sonst gesund. Die Veränderungen sprachen nicht auf die systemische Behandlung mit Antibiotika oder Glukokortikoiden in einer antiinflammatorischen Dosis an. Bei drei Katzen kam es zu einer spontanen, dauerhaften Remission der Befunde nach einem Krankheitsverlauf von 3 bis 9 Monaten. Resumen En cuatro gatos se diagnosticó una dermatitis piogranulomatosa o granulomatosa esteril idiopática. Se distinguieron dos síndromes clínicopatológicos. Dos gatos presentaban una dermatitis papulonodular prurítica situada en la cabeza y en los pabellones auriculares, con unas biopsias cutáneas caracterizadas por una dermatitis piogranulomatosa perifolicular. Los otros dos animales presentaban placas preauriculares y laterales pruríticas con un cuadro histopatológico caracterizado por una dermatitis granulomatosa difusa con numerosas células gigantes istiocíticas multinucleadas y hemorragias. No se detectaron alteraciones hematológicas, bioquímicas ni en la orina, y los animales se encontraban en buen estado de salud. Las lesiones no respondieron ni al tratamiento con antibióticos sistémicos ni al tratamiento con glucocorticoides a dosis antiinflamatorias. Tres de los animales sufrieron una remisión espontánea después de 3 a 9 meses.     

A pharmacokinetic study of digoxin in the horse

Digoxin was administered orally and intravenously to seven healthy adult mares and geldings in two separate trials. At a dose of 44 microgram digoxin/kg body weight, the oral study was characterized by an absorption phase with a mean (+/- 1 standard deviation) peak serum digoxin concentration of 2.21 ng/ml (+/- 0.45) at a mean of 2.29 h (+/- 1.52) after administration. A second rise in serum digoxin concentration started about 6-8 h after administration and extended to about 20 h after administration. The mean bioavailability (F) was 23.38% (+/- 5.96). At a dose of 22 microgram digoxin/kg body weight, the intravenous study was characterized by a two-compartment model with the following mean pharmacokinetic measurements: distribution rate constant (alpha), 1.391 h-1 (+/- 0.1909); zero-time serum digoxin concentration determined from the distribution phase (A), 21.247 ng/ml (+/- 5.6614); elimination rate constant (beta), 0.0409 h-1 (+/- 0.0069); zero-time serum digoxin concentration determined from the elimination phase (B), 3.82 ng/ml (+/- 0.433); apparent specific volume of distribution uncorrected for protein binding (Vd beta), 5.003 l/kg (+/- 0.5177). The mean beta corresponded to a biological half-life (T1/2 beta) of 16.9 h. Based upon results of this study, theoretically achievable steady-state serum digoxin concentrations were calculated for maintenance doses given by oral and intravenous routes of administration with appropriate two-compartment, multiple-dose formulae. Loading doses were also calculated for each route. It is the opinion of the authors that the oral route of administration of digoxin is effective in the horse and may preclude the potential risks posed by the high serum digoxin concentrations immediately following intravenous administration.     

Marine environment‐based forecasting of coho salmon (Oncorhynchus kisutch) adult recruitment

Generalized additive models (GAMs) were used to investigate the relationships between annual recruitment of natural coho salmon (Oncorhynchus kisutch) from Oregon coastal rivers and indices of the physical ocean environment. Nine indices were examined, ranging from large‐scale ocean indicators, e.g., Pacific Decadal Oscillation (PDO), to indicators of the local ecosystem (e.g., coastal water temperature near Charleston, OR). Generalized additive models with two and three predictor variables were evaluated using a set of performance metrics aimed at quantifying model skill in short‐term (approximately 1 yr) forecasting. High explanatory power and promising forecast skill resulted when the spring/summer PDO averaged over the 4 yr prior to the return year was used to explain a low‐frequency (multi‐year) pattern in recruitment and one or two additional variables accounted for year‐to‐year deviations from the low‐frequency pattern. More variance was explained when averaging the predictions from a set of models (i.e., taking the ensemble mean) than by any single model. Making multiple forecasts from a set of models also provided a range of possible outcomes that reflected, to some degree, the uncertainty in our understanding of how salmon productivity is driven by physical ocean conditions.     

Responses in growth rate of larval northern anchovy (Engraulis mordax) to anomalous upwelling in the northern California Current

We examined variability in growth rate during the larval stage of northern anchovy (Engraulis mordax) in response to physical and biological environmental factors in 2005 and 2006. The onset of spring upwelling was anomalously delayed by 2–3 months until mid‐July in 2005; in contrast, spring upwelling in 2006 began as a normal year in the northern California Current. Larval and early juvenile E. mordax were collected in August, September, and October off the coast of Oregon and Washington. Hatch dates ranged from May to September, with peaks in June and August in 2005 and a peak in July in 2006, based on the number of otolith daily increments. Back‐calculated body length‐at‐age in the June 2005 hatch cohort was significantly smaller than in the August 2005 cohort, which had comparable growth to the July 2006 cohort. Standardized otolith daily increment widths as a proxy for seasonal variability in somatic growth rates in 2005 were negative until late July and then changed to positive with intensification of upwelling. The standardized increment width was a positive function of biomass of chlorophyll a concentration, and neritic cold‐water and oceanic subarctic copepod species sampled biweekly off Newport, Oregon. Our results suggest that delayed upwelling in 2005 resulted in low food availability and, consequently, reduced E. mordax larval growth rate in early summer, but once upwelling began in July, high food availability enhanced larval growth rate to that typical of a normal upwelling year (e.g., 2006) in the northern California Current.     

Modified Tenoscopic Method for Carpal Flexor Retinaculum Release in a Horse

Objective— To report the use of a proximolateral endoscopic portal with a distolateral instrument portal for carpal retinaculum release in a horse clinically affected with carpal canal syndrome. Study Design— Clinical report. Animals— A 4‐year‐old Thoroughbred female. Methods— Carpal canal syndrome secondary to traumatic suppurative tenosynovitis was treated by accessory carpal bone debridement and carpal retinaculum release using a tenoscopic approach to the carpal flexor synovial sheath through a proximolateral endoscope portal and a distolateral instrument portal. Results— Resolution of carpal sheath effusion and lameness occurred allowing racing 14 months later. Use of a distolateral instrument portal was not associated with complications or iatrogenic damage to neurovascular structures and reduced endoscope and instrument interference and offered easier access to the distal aspect of the carpal sheath. Conclusions— Carpal retinaculum release may be safely accomplished with a distolateral instrument portal when access to the distal aspect of the carpal sheath is needed. Clinical Relevance— The distolateral instrument portal described may be a useful alternative to a proximolateral portal when distal carpal sheath instrument access is necessary or advantageous.