Pharmacokinetics of pipemidic acid in chickens after single intravenous and oral dosings

The pharmacokinetics of pipemidic acid after 2 single doses were studied in broiler chickens. Chickens were given single IV and oral doses of 10 and 30 mg of pipemidic acid/kg of body weight. Blood samples were collected over 8 hours after each dose administration. High-pressure liquid chromatography with UV detection was used to determine concentrations in plasma of pipemidic acid. The plasma concentration-time curves after IV administration followed 2-compartment characteristics, rapid initial distribution phase, and a terminal elimination phase. The pharmacokinetic variables differed significantly between single doses of 10 and 30 mg of pipemidic acid/kg. Mean disposition variables were a half-life at alpha phase of 0.06 hours or 0.33 hours, a half-life at beta phase of 1.18 hours or 1.72 hours, a volume of distribution in the central compartment of 0.12 L/kg or 0.31 L/kg, a volume of distribution during the elimination beta phase of 1.64 L/kg or 1.05 L/kg, and a total plasma clearance of 0.97 L/h.kg or 0.41 L/h.kg, for the 10 or 30 mg/kg dose, respectively. After oral administration, the pipemidic acid plasma profile could be adequately described by a 1-compartment model. After the single oral doses of 10 and 30 mg of pipemidic acid/kg, pipemidic acid was absorbed rapidly (time to maximal concentration of 0.31 hours or 0.71 hours) and eliminated with a mean half-life of 0.86 hours or 0.61 hours, respectively. The bioavailability was 39% at 10 mg of pipemidic acid/kg and 61% at 30 mg of pipemidic acid/kg.     

Fine needle aspiration biopsy of malignant tumors in dogs and cats: a report of 102 cases

Fine needle aspiration biopsy is a fast and inexpensive technique well tolerated by animals. Its efficacy for the diagnosis of malignancy and determination of cellular origin was investigated for 97 malignant tumors and five benign lesions in 83 dogs and 19 cats. Histological examination of the lesions was performed in each case. Malignancy was detected by cytology in 69% of the malignant tumors. The cellular origin of the lesion was determined in 74% of the cases. Confirmation of malignancy and determination of cellular origin permitted an early diagnosis and prognosis. Since fine needle aspiration biopsy and cytology cannot definitely rule out malignancy, a surgical biopsy and histopathology should be done when malignancy is suspected clinically and not confirmed cytologically. Specimens of good quality, adequate collaboration between the cytologist and clinicians, and sufficient knowledge of pathology and cytology are basic requirements for obtaining good results with fine needle aspiration biopsy and cytology.     

Neuritis of the cauda equina in a dog

This study presents the first case report of neuritis of the cauda equina in a dog, including characterisation of the inflammatory infiltrate. The dog in question, a 6-year-old Welsh springer spaniel, was presented with flaccid tail and faecal and urinary incontinence. The histological lesions included severe mononuclear cell infiltration of the nerve roots of the cauda equina and of the lumbar nerve roots. The infiltrate was composed of large numbers of T-lymphocytes and B-lymphocytes and small numbers of macrophages. Polymerase chain reactions of brain and spinal tissues were positive for Neospora caninum.     

Season of the year influences testosterone secretion in bulls administered luteinizing honrmone

The objective of the present study was to evaluate the secretion of testosterone (T) in bulls in response to the administration of varying doses of bovine LH (bLH) during the four seasons of the year. Five adult bulls (4 yr of age) were treated with an amount of bLH that was estimated to induce a 5 ng/mL amplitude pulse of LH in blood serum on five consecutive days around the spring equinox, summer solstice, fall equinox, and winter solstice. Five hours after this dose, bulls were treated with bLH in amounts that were estimated to induce a 0.25, 0.5, 1, 2, or 4 ng/mL amplitude LH pulse in blood serum in a Latin square design. Blood samples were collected for 5 h after administration of a dose of bLH that was estimated to induce the 5-ng amplitude LH pulse, and for 3 h after administration of the variable doses of bLH, and were then assayed for concentrations of T. Average concentrations and amplitude of T release after doses of bLH that were estimated to induce the 5-ng amplitude LH pulses were greater during the spring and summer than during the winter (P < 0.05). The area under the release curve (AUC) was greater during the spring than during the winter (P < 0.05). During the 3 h after treatment with the variable doses of bLH, T response was affected by dose (P < 0.001) and season (P < 0.001), but there was no dose x season interaction. Testosterone response increased in a dose-dependent fashion for all variables studied. The greatest average concentrations of T and AUC were observed in the spring compared with the fall and winter (P < 0.05). These data support our working hypothesis that testes of bulls are more responsive in releasing T in response to bLH stimulation in the spring and summer compared with the winter; however, there were no changes in sensitivity of the testes to LH during different seasons of the year as indicated by the lack of a dose of bLH x season interaction.     

Renal handling of calcium and phosphorus in experimental renal hyperparathyroidism in dogs

Twenty-four hour urinary excretion, fractional excretion and the filtered load of calcium and phosphorus were monitored as hyperparathyroidism evolved in a model of progressive canine renal failure. Thirteen beagles of both sexes aged four and a half months were used. Nine of them were subjected to a renal damaging schedule (neomycine, 60 mg/kg/48 h, IM, 32 weeks) in order to induce chronic renal failure leading to secondary hyperparathyroidism (2HPT group). The remaining four were kept as the control group. The experiment was conducted over 32 weeks. Blood and 24 h urine were collected every four weeks. Calcium, phosphorus and creatinine were analyzed. Plasma parathormone and calcitonin were determined at weeks 0, 12, 24 and 32. The level of renal function in the 2HPT animals was reduced to 25% of that of the controls (endogenous creatinine clearance was 0.45 +/- 0.22 mL/min/kg as opposed to 1.81 +/- 0.54 mL/min/kg). Hyperparathyroidism was confirmed by a progressive increase in the levels of the parathyroid hormone. Calcitonin levels were not modified. A tendency to hypocalcaemia was observed, reaching statistically significant levels from the twenty-eighth week of the study, when hyperphosphataemia also became significant. Daily urinary excretion of calcium and phosphorus remained at values considered normal throughout the experiment with no alteration imputable to the impaired renal function. This is explained by the decrease in the filtered load of these elements (in both cases statistically significant from the 24th week on) being associated with an increase in their fractional excretion. Thus, calcium and phosphorus urinary excretion values could be maintained in a normal range up to the end of the experiment, showing that renal calcium handling in dogs with experimentally induced renal failure seems to differ from that observed in human patients.     

Experimental infection of Black Belly and INRA 401 straight and crossbred sheep with trichostrongyle nematode parasites

Compared to INRA 401 lambs reared in France, Black Belly (BB) lambs reared in Guadeloupe (F.W.I.) were highly resistant to both primary and secondary experimental infection with Haemonchus contortus. To investigate this huge inter-breed difference, a nucleus flock of BB was constituted, and experiments were conducted to: (i) confirm this difference in lambs born in France, (ii) check whether it was similar for Trichostrongylus colubriformis and Teladorsagia circumcincta, and (iii) find out whether this difference was age-related. Forty BB lambs, 84 F1 lambs (BB siresxINRA 401 ewes) and 88 INRA 401 lambs born in two cohorts were used in an experimental design involving three host breeds, both genders and two age-groups (3.5- and 7-month-old when first infected). The limited availability of BB lambs made the study incomplete. Infection consisted of the administration of two doses of 10,000 infective larvae of one of the nematode species, separated by an anthelmintic treatment and an interval of 1 week before the second dose was administered. Fecal egg counts (FECs) were done on Days 28 and 35 after each infection; ewe lambs of the INRA 401 and F1 breeds were necropsied, the worm burden was established, the length of the female worms measured and the eggs in utero counted. For H. contortus and T. colubriformis, the FEC was lower in the BB than in the INRA 401 lambs, and the FEC found for the F1 lambs was intermediate. For T. circumcincta, only data for the F1 and INRA 401 lambs were available, and the FECs for these breeds were the same. In all three breeds, the FEC determined after the second dose was significantly lower than that found after the first dose in the ewe lambs, but not in the ram lambs. Infecting the lambs when they were 7- instead of 3.5-month-old significantly lowered egg excretion of both parasites in the F1 (P<0.0001), but not the INRA 401 lambs. Worm numbers in the F1 and in the INRA 401 ewe lambs confirmed the FEC data, many F1 lambs being free of T. colubriformis. The H. contortus female worms were shorter and had fewer eggs in utero in the F1 than in the INRA 401 lambs. A higher proportion of T. circumcincta was at the fourth larval stage in the F1 lambs. In conclusion, the BB breed is much more resistant than INRA 401 to H. contortus, with the F1 lambs being more like the BBs after the second dose. This difference was also found for T. colubriformis and, to a lesser extent, for T. circumcincta.     

Effect of dietary Schizochytrium microalga oil and fish oil on plasma cholesterol level in rats

The purpose of the study was to test the hypothesis that the dietary oils with different content of n‐3 polyunsaturated fatty acids (PUFA) eicosapentaenoic acid (EPA) + docosahexaenoic acid (DHA) affect plasma lipid level in rats in a different degree. The diets with 6% of fish oil (FO) and Schizochytrium microalga oil (SchO; EPA+DHA content in the diets 9.5 + 12.3 and 2.6 + 29.5% of the sum of total fatty acids, respectively) were used; the diet with 6% of safflower oil (high content of n‐6 PUFA linoleic acid, 65.5%; EPA+DHA content 0.7 + 0.9%) was used as a control. The difference between FO and SchO was established only in the case of plasma triacylglycerol (TAG) level: plasma TAG of the FO‐fed rats did not differ from the control rats (p > 0.05), while SchO decreased (p < 0.05) plasma TAG to 46% of the control. On the other hand, FO and SchO decreased (p < 0.05) total plasma cholesterol (TC) in rats in the same extent, to 73% of the control. Regarding the underlying mechanisms for the TC decrease, both SchO and FO up‐regulated hepatic Insig‐1 gene (181 and 133% of the control; p < 0.05), which tended (p = 0.15 and p = 0.19 respectively) to decrease the amount of hepatic nSREBP‐2 protein (61 and 66% of the control). However, neither SchO nor FO influenced hepatic 3‐hydroxy‐3‐methyl‐glutaryl‐CoA reductase gene expression (p > 0.05); SchO (but not FO) increased (p < 0.05) low‐density lipoprotein receptor mRNA in the liver. It was concluded that the decrease of total plasma cholesterol might be caused by an increased cholesterol uptake from plasma into the cells (in the case of SchO), but also by other (in the present study not tested) mechanisms.     

Gait analysis in a cat with scapular luxation and contralateral forelimb amputation

This report describes the use of a pressure-sensitive walkway to evaluate an uncommon case of a cat with dorsal luxation of the left scapula and an amputated right forelimb. The findings suggest that limb amputation induced load redistribution mostly to the contralateral forelimb despite the scapular luxation.