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- Author or Editor: Chad W. Schmiedt x
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Objective—To identify preoperative variables associated with postoperative hypocalcemia in dogs with primary hyperparathyroidism undergoing parathyroidectomy.
Design—Retrospective case series.
Procedures—Medical records of dogs undergoing parathyroidectomy for treatment of primary hyperparathyroidism between January 2004 and January 2009 at 4 institutions were reviewed; data regarding various preoperative variables and postoperative serum total and ionized calcium concentrations were recorded. Preoperative ultrasonographic and surgical findings were compared regarding laterality (right, left, or bilateral) of parathyroid gland lesions. Data were analyzed via ANOVA, simple linear regression, and multiple linear regression to identify associations between preoperative variables and postoperative serum total and ionized calcium nadir concentrations.
Results—Preoperative variables significantly associated with low postoperative serum total calcium nadir concentrations included old age, history of weakness, lack of gastrointestinal tract signs, high serum parathyroid hormone concentration, and low serum calcium-phosphorus concentration product value. Preoperative variables significantly associated with low postoperative serum ionized calcium nadir concentrations included sexually intact status, low body weight, high serum urea nitrogen concentration, and lack of polyuria and polydipsia in the history. Age, body weight, serum calcium-phosphorus concentration product, and serum concentrations of parathyroid hormone and urea nitrogen were included in the final multiple linear regression model for prediction of postoperative serum calcium concentrations. Ultrasonography was performed in 58 dogs; results for 44 (75.9%) dogs agreed with surgical findings regarding laterality of parathyroid gland lesions.
Conclusions and Clinical Relevance—Prediction of postoperative hypocalcemia in dogs in this study with primary hyperparathyroidism that underwent parathyroidectomy was difficult and depended on multiple (history, physical examination, and clinicopathologic) factors.
OBJECTIVE To determine the rate of and factors associated with survival to hospital discharge in dogs with uroabdomen.
DESIGN Retrospective case series.
ANIMALS 43 dogs with uroabdomen confirmed at 2 veterinary teaching hospitals from 2006 through 2015.
PROCEDURES Medical records were reviewed and data extracted regarding cause and location of urinary tract rupture, serum creatinine concentration and other variables at hospital admission, and outcomes. Variables were tested for associations with survival to hospital discharge.
RESULTS Urinary tract rupture occurred in the urinary bladder (n = 24 [56%]), urethra (11 [26%]), kidney (2 [5%]), ureter (1 [2%]), both the urinary bladder and kidney (1 [2%]), and undetermined sites (4 [9%]). Rupture causes included traumatic (20 [47%]), obstructive (9 [21%]), and iatrogenic (7 [16%]) or were unknown (7 [16%]). Surgery was performed for 37 (86%) dogs; the defect was identified and surgically corrected in 34 (92%) of these dogs. Hypotension was the most common intraoperative complication. Nineteen dogs had information recorded on postoperative complications, of which 10 (53%) had complications that most often included death (n = 3) and regurgitation (3). Thirty-four (79%) dogs survived to hospital discharge. Dogs with intraoperative or postoperative complications were significantly less likely to survive than dogs without complications. Serum creatinine concentration at admission was not associated with survival to discharge.
CONCLUSIONS AND CLINICAL RELEVANCE A high proportion of dogs with uroabdomen survived to hospital discharge. No preoperative risk factors for nonsurvival were identified. Treatment should be recommended to owners of dogs with uroabdomen.
Objective—To evaluate the effect of the duration of cold Ischemia on the renin-angiotensin system during renal transplantation In cats and to define the potential Influence of vasoactive factors in renal tissue following cold ischemic storage versus warm ischemic storage
Animals—10 purpose-bred 6-month-old sexually Intact female cats
Procedures—10 cats underwent renal autotransplantation after 30 minutes (n = 5) or 3 hours (5) of simple, ex vivo cold storage of renal autographs. Following autograft reperfusion, direct hemodynamic variables were measured with a telemetric Implant and samples were collected for plasma renin concentration. Activation of vascular-related genes (renin, endothelin, and angiotensin converting enzyme) relative to 2-hour simple cold or warm ischemia was also evaluated.
Results—No significant difference between groups was detected In any of the hemodynamic variables or postreperfusion plasma renin concentrations measured in this study relative to the duration of cold ischemic storage. There was also no difference between warm- and cold-stored kidneys in the expression of vascular-related genes
Conclusions and Clinical Relevance—Prolonged renal Ischemia for clinically relevant durations does not appear to predispose clinically normal cats to altered hemodynamics or high plasma renin concentrations following graft reperfusion. Activation of vasoactive genes does not appear to be Influenced by type of Ischemia over 2 hours. (Am J Vet Res 2010;71:1220-1227)
Objective—To determine and compare the ratio of uracil (U) to dihydrouracil (UH2) concentrations in plasma as an indicator of dihydropyrimidine dehydrogenase activity in clinically normal dogs and dogs with neoplasia or renal insufficiency.
Animals—101 client-and shelter-owned dogs.
Procedures—Study dogs included 74 clinically normal dogs, 17 dogs with neoplasia, and 10 dogs with renal insufficiency. For each dog, a blood sample was collected into an EDTA-containing tube; plasma U and UH2 concentrations were determined via UV high-performance liquid chromatography, and the U:UH2 concentration ratio was calculated. Data were compared among dogs grouped on the basis of sex, clinical group assignment, reproductive status (sexually intact, spayed, or castrated), and age.
Results—Mean ± SEM U:UH2 concentration ratio for all dogs was 1.55 ± 0.08 (median, 1.38; range, 0.4 to 7.14). In 14 (13.9%) dogs, the U:UH2 concentration ratio was considered abnormal (ie, > 2). Overall, mean ratio for sexually intact dogs was significantly higher than that for neutered dogs; a similar difference was apparent among males but not females. Dogs with ratios > 2 and dogs with ratios ≤ 2 did not differ significantly with regard to sex, clinical group, reproductive status, or age.
Conclusions and Clinical Relevance—Determination of the U:UH2 concentration ratio was easy to perform. Ratios were variable among dogs, possibly suggesting differences in dihydropyrimidine dehydrogenase activity. However, studies correlating U:UH2 concentration ratio and fluoropyrimidine antimetabolite drug tolerability are required to further evaluate the test's validity and its appropriate use in dogs.
OBJECTIVE To compare the attenuation of the angiotensin I–induced blood pressure response by once-daily oral administration of various doses of angiotensin receptor blockers (irbesartan, telmisartan, and losartan), benazepril hydrochloride, or lactose monohydrate (placebo) for 8 days in clinically normal cats.
ANIMALS 6 healthy cats (approx 17 months old) with surgically implanted arterial telemetric blood pressure–measuring catheters.
PROCEDURES Cats were administered orally the placebo or each of the drug treatments (benazepril [2.5 mg/cat], irbesartan [6 and 10 mg/kg], telmisartan [0.5, 1, and 3 mg/kg], and losartan [2.5 mg/kg]) once daily for 8 days in a crossover study. Approximately 90 minutes after capsule administration on day 8, each cat was anesthetized and arterial blood pressure measurements were recorded before and after IV administration of each of 4 boluses of angiotensin I (20, 100, 500, and 1,000 ng/kg). This protocol was repeated 24 hours after benazepril treatment and telmisartan (3 mg/kg) treatment. Differences in the angiotensin I–induced change in systolic arterial blood pressure (ΔSBP) among treatments were determined.
RESULTS At 90 minutes after capsule administration, only losartan did not significantly reduce ΔSBP in response to the 3 higher angiotensin doses, compared with placebo. Among drug treatments, telmisartan (3 mg/kg dosage) attenuated ΔSBP to a significantly greater degree than benazepril and all other treatments. At 24 hours, telmisartan was more effective than benazepril (mean ± SEM ΔSBP, 15.7 ± 1.9 mm Hg vs 55.9 ± 12.42 mm Hg, respectively).
CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that telmisartan administration may have advantages over benazepril administration for cats with renal or cardiovascular disease.
Objective—To determine whether signalment, duration of hernia, clinical signs, contents of hernia, CBC and serum biochemical abnormalities, concurrent injuries, perioperative treatment and administration of analgesics, results of intraoperative anesthetic monitoring data, or level of training of the veterinarian performing the herniorrhaphy was associated with mortality rate after surgical repair of traumatic diaphragmatic hernia in cats.
Procedure—Review of medical records and a telephone follow-up with owners and referring veterinarians were performed.
Results—Mean age of affected cats was 3.6 years; cats that survived to the time of discharge were significantly younger than cats that died or were euthanatized. Tachypnea was the most common clinical sign at hospital admission; cats that survived to the time of discharge had significantly higher respiratory rates than cats that died or were euthanatized after surgery. Postoperative complications developed in 50% of cats; tachypnea and dyspnea were most common. Mortality rate was not associated with duration of hernia or results of preoperative CBC and serum biochemical analyses, but was significantly associated with concurrent injuries. Mortality rate was not associated with hernia contents, intraoperative use of positive inotropes or corticosteroids, episodes of hypotension or severe hypoxia during anesthesia, or level of training of the veterinarian performing the surgery.
Conclusions and Clinical Relevance—Cats that are older or have low to mildly increased respiratory rates and concurrent injuries are more likely to die after surgical repair of traumatic diaphragmatic hernia. (J Am Vet Med Assoc 2003;222:1237–1240)
Case Description—A 40.3-kg (88.7-lb) 6-year-old spayed female Labrador Retriever was evaluated because of acute unilateral epistaxis.
Clinical Findings—During the initial evaluation of the dog, systemic hypertension and a left adrenal gland mass were detected. The left adrenal gland mass was surgically removed; results of histologic examination of the mass indicated it was a pheochromocytoma. Ten months later, the dog was evaluated because of persistent systemic hypertension and development of polyuria, polydipsia, and excessive panting. Abdominal ultrasonography revealed a mass in the cranial aspect of the right adrenal gland; results of MRI suggested the mass was a malignant tumor.
Treatment and Outcome—Epistaxis resolved after treatment and resolution of severe systemic hypertension. A partial right adrenalectomy was performed to remove the right adrenal gland mass. Results of histologic examination of the mass indicated it was a well-differentiated carcinoma of the cortex of the adrenal gland. Results of ACTH stimulation tests after surgery indicated the dog had adequate adrenal gland function.
Clinical Relevance—Partial adrenalectomy may be a safe and feasible treatment option to preserve adrenal gland function in dogs with small eccentrically located adrenal gland masses, particularly for dogs that have undergone removal of the contralateral adrenal gland.
Objective—To characterize the pharmacokinetics of zidovudine (AZT) in cats.
Animals—6 sexually intact 9-month-old barrier-reared domestic shorthair cats.
Procedure—Cats were randomly alloted into 3 groups, and zidovudine (25 mg/kg) was administered IV, intragastrically (IG), and PO in a 3-way crossover study design with 2-week washout periods between experiments. Plasma samples were collected for 12 hours after drug administration, and zidovudine concentrations were determined by high-performance liquid chromatography. Maximum plasma concentrations (Cmax), time to reach Cmax (Tmax), and bioavailability were compared between IG and PO routes. Area under the curve (AUC) and terminal phase halflife (t½) among the 3 administration routes were also compared.
Results—Plasma concentrations of zidovudine declined rapidly with t½ of 1.4 ± 0.19 hours, 1.4 ± 0.16 hours, and 1.5 ± 0.28 hours after IV, IG, and PO administration, respectively. Total body clearance and steady-state volume of distribution were 0.41 ± 0.10 L/h/kg and 0.82 ± 0.15 L/kg, respectively. Mean Tmax for IG administration (0.22 hours) was significantly shorter than Tmax for PO administration (0.67 hours). The AUC after IV and PO administration was 64.7 ± 16.6 mg·h/L and 60.5 ± 17.0 mg·h/L, respectively, whereas AUC for the IG route was significantly less at 42.5 ± 9.41 mg·h/L. Zidovudine was well absorbed after IG and PO administration with bioavailability values of 70 ± 24% and 95 ± 23%, respectively.
Conclusions and Clinical Relevance—Cats had slower clearance of zidovudine, compared with other species. Plasma concentrations of zidovudine were maintained above the minimum effective concentration for inhibiting FIV replication by 50% (0.07µM [0.019 µg/mL] for wild-type FIV clinical isolate) for at least 12 hours after IV, IG, or PO administration. (Am J Vet Res 2004;65:835–840)