Increased pulmonary transit times in asymptomatic dogs with mitral regurgitation

Pulmonary transit time (PTT) normalized to heart rate (nPTT) is a measure of the pulmonary blood volume (PBV) to stroke volume ratio (PBV/SV). It is an index of cardiac performance. To determine the effect of compensated mitral regurgitation (CMR) and decompensated mitral regurgitation (DMR) caused by valvular endocardiosis on the index nPTT, we measured nPTT by first-pass radionuclide angiocardiography and ECG in 13 normal dogs, 18 dogs with CMR, and 13 dogs with DMR. PTT was measured as time between onset of appearance of activity at the pulmonary trunk and the left atrium. In the normal dogs, the relationship between PTT and mean R-R interval (mRR) was PTT = 4.08 x mRR + 0.15 (R2 = 0.71). Normal nPTT was 4.4 +/- 0.6 (SD) (range. 3.6-5.3). in CMR, 6.3 +/- 1.6 (SD) (range, 4.0-9.7). and in DMR, 11.9 +/- 3.4 (SD) (range, 8.0-18.8). The differences among all groups were significant. Heart rates were 110 +/- 22 bpm in normal dogs, 111 +/- 20 in dogs with CMR, and 144 +/- 18 in dogs with DMR (P < .001 for difference between DMR group and normal and CMR groups). Increased nPTT in CMR indicates preclinical heart pump dysfunction. Heart rate-normalized pulmonary transit times may be a useful index of heart function in mitral regurgitation.     

Effects of acepromazine on renal function in anesthetized dogs

OBJECTIVE: To investigate the effects of IM administration of acepromazine on indices of relative renal blood flow and glomerular filtration rate (GFR) by means of scintigraphy, as well as the effects on physiologic, hematologic, and serum biochemical variables in anesthetized dogs, compared with effects of administration of saline. ANIMAL: 6 healthy Beagles. PROCEDURE: Acepromazine (0.1 mg/kg) or physiologic saline (0.9 NaCI) solution was administered IM 30 minutes prior to induction of anesthesia with thiopentone; anesthesia was maintained with inspired isoflurane for 2.25 hours. Blood gases and circulatory and ventilatory variables were monitored. Renal function was evaluated by scintigraphic measurements of GFR and relative renal blood flow and analyses of serum and urine. Statistical analyses used ANOVA or Friedman ANOVA. RESULTS: Values of relative renal blood flow and GFR remained high despite low blood pressures. After administration of acepromazine, mean +/- SD arterial blood pressure was 66 +/- 8 mm Hg during anesthesia; this value was below the threshold (80 mm Hg) for renal autoregulation of GFR. In comparison, mean arterial blood pressure after administration of saline was significantly higher (87 +/- 13 mm Hg). However, between treatments, there were no significant differences in GFR, relative renal blood flow, or other indices of renal function. CONCLUSIONS AND CLINICAL RELEVANCE: Measurements of renal function and blood flow in dogs during anesthesia with thiopentone and isoflurane did not differ significantly between treatments, which suggested that acepromazine protects renal function despite inducing reduction in blood pressure, compared with effects of administration of saline.     

Progressive Myelopathy in a Dog Caused by Thorium Dioxide

A study of the use of Thorotrast as a contrast media in myelograms in dogs is presented, indicating that the material introduced into the cerebro-spinal fluid, will become permanently associated with the meninges, leading to the development of myelopathy.     

Expression of adiponectin and its receptors in swine

Adiponectin is an adipocyte-derived hormone that plays an important role in lipid metabolism and glucose homeostasis. Objectives of this study were 1) to determine the presence and distribution of adiponectin and its receptors 1 and 2 (adipoR1 and adipoR2) in porcine tissues; 2) to characterize pig adiponectin, adipoR1, and adipoR2 mRNA levels in various fat depots from three different breeds of pigs; and 3) to study, in stromal-vascular cell culture, the effects of leptin and tumor necrosis factor-alpha (TNFalpha) on pig adiponectin, adipoR1, and adipoR2 gene expression. To this end, fat Chinese Upton Meishan (UM, n = 10), lean Ham Line (HL, n = 10), and Large White (LW, n = 10) gilts were used. We report the isolation of partial cDNA sequences of pig adipoR1 and adipoR2. Porcine-deduced AA sequences share 97 to 100% homology with human and murine sequences. Pig adipoR1 mRNA is abundant in skeletal muscle, visceral fat, and s.c. fat tissues, whereas adipoR2 mRNA is predominantly expressed in liver, heart, skeletal muscle, and visceral and s.c. fat tissues. Pig adiponectin mRNA levels in s.c. and visceral fat tissues were not associated with plasma insulin and glucose in fasting animals. Subcutaneous (r = -0.44, P < 0.05), visceral (r = -0.43, P < 0.05), and total body fat (r = -0.42, P < 0.05) weights were negatively correlated with adiponectin mRNA levels measured in visceral, but not s.c., fat. Pig adipoR1 and adipoR2 mRNA levels, in visceral fat, were less expressed in fat UM gilts than in the lean HL gilts (P < 0.05). Inverse associations were found between s.c. (r = -0.57, P < 0.01), visceral (r = -0.46, P < 0.05), and total body fat (r = -0.56, P < 0.01) weights and adipoR2 mRNA levels in visceral fat only. We were unable to find such associations for adipoR1 mRNA levels in the overall gilt population. The current study demonstrated that TNFalpha downregulates adiponectin and adipoR2, but not adi-poR1, mRNA levels in stromal-vascular cell culture. Moreover, leptin significantly decreased adiponectin mRNA levels, whereas there was no effect on adiponectin receptors. We conclude that adiponectin and adi-poR2 mRNA levels, but not adipoR1, are modulated in pig visceral fat tissues. Furthermore, our results indicate that TNFalpha interferes with adiponectin function by downregulation of adipoR2 but not of adipoR1 mRNA levels in pigs.     

Efficacy of enalapril for prevention of congestive heart failure in dogs with myxomatous valve disease and asymptomatic mitral regurgitation

We evaluated the long-term effect of early angiotensin-converting enzyme (ACE) inhibition (enalapril maleate) as monotherapy to postpone or prevent congestive heart failure (CHF) in asymptomatic dogs with mitral regurgitation (MR) attributable to myxomatous valvular disease (MVD) in a prospective, randomized, double-blinded, placebo-controlled multicenter trial involving 14 centers in Scandinavia. Two hundred twenty-nine Cavalier King Charles (CKC) Spaniels with MR attributable to MVD but no signs of CHF were randomly allocated to treatment with enalapril 0.25-0.5 mg daily (n = 116) or to placebo groups (n = 113). Each dog was evaluated by physical examination, electrocardiography, and thoracic radiography at entry and every 12 months (+/-30 days). The number of dogs developing heart failure was similar in the treatment and placebo groups (n = 50 [43%] and n = 48 [42%], respectively; P = .99). The estimated means, adjusted for censored observations, for the period from initiation of therapy to heart failure were 1,150 +/- 50 days for dogs in the treatment group and 1,130 +/- 50 days for dogs in the placebo group (P = .85). When absence or presence of cardiomegaly at the entrance of the trial was considered, there were still no differences between the treatment and placebo groups (P = .98 and .51, respectively). Multivariate analysis showed that enalapril had no significant effect on the time from initiation of therapy to heart failure (P = .86). Long-term treatment with enalapril in asymptomatic dogs with MVD and MR did not delay the onset of heart failure regardless of whether or not cardiomegaly was present at initiation of the study.     

EMPHYSEMATOUS HEPATIC ABSCESS ASSOCIATED WITH TRAUMA, NECROTIC HEPATIC NODULAR HYPERPLASIA AND ADENOMA IN A DOG: A CASE HISTORY REPORT

A 13-year-old male Setter-Springer crossbred dog was presented with signs of acute peritonitis three days after blunt abdominal trauma. In abdominal radiographs, a bubbly accumulation of gas in the central and cranioventral parts of the liver silhouette and mild peritoneal effusion were seen. At laparatomy, firm, necrotic, nodular hepatic masses containing gas were found to be ruptured. The histologic diagnoses were hepatic adenoma with hepatic necrosis and nodular hepatic hyperplasia. The pathogenesis of hepatic abscessation and the radiographic differential diagnosis of extraluminal abdominal gas are discussed.     

Some properties of a mechanism delaying penetration of insecticides into houseflies

The penetration of insecticides into houseflies, with and without the factor that delays penetration, was studied by measuring the amounts of the insecticides on the surface of the flies at intervals after treatment. The factor slowed the entry of all the insecticides tested, but its effect depended on the dose, and had little or no effect when the dose applied was big (20 μmUg/fiy). Penetration in all strains, susceptible and resistant, increased but not proportionally to the size of the dose. The rate insecticide was lost from the surface slowed with time and increasing age of the insects. It was faster in males than females, and was always faster in flies without the penetration factor. The differences in penetration between the flies with and without the factor was less with n-dodecane as solvent than with acetone. With all strains, rate of loss from the surface was slowest with dieldrin. Diazinon, parathion and chlorthion-ethyl were lost at about the same rate; diazoxon penetrated fastest.