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Biomedical subjects

R H Sutton

Publications and source records attributed to R H Sutton.

At least 19 recordsLinked to original sources
PubMed2004

Carboplatin pharmacokinetics following a single-dose infusion in sulphur-crested cockatoos (Cacatua galerita).

OBJECTIVE: To determine the pharmacokinetics of carboplatin in sulphur-crested cockatoos, so that its use in clinical studies in birds can be considered. DESIGN: A pharmacokinetic study of carboplatin, following a single intravenous (IV) or intraosseus (IO) infusion over 3 min, was performed in six healthy sulphur-crested cockatoos (Cacatua galerita). PROCEDURE: Birds were anaesthetised and a jugular vein cannulated for blood collection. Carboplatin (5 mg/kg) was infused over 3 min by the IV route in four birds via the contralateral jugular vein, and by the IO route in two birds via the ulna. Serial blood samples were collected for 96 h after initiation of the infusion. Tissue samples from 11 organs were obtained at necropsy, 96 h after carboplatin administration. Total Pt and filterable Pt in plasma and tissue Pt concentrations were assayed by inductively coupled plasma-mass spectrometry. A noncompartmental pharmacokinetic analysis was performed on the plasma data. RESULTS: The mean +/- SD for the Cmax of filterable Pt was 27.3 +/- 4.06 mg/L and in all six birds occurred at the end of the 3 min infusion, thenceforth declining exponentially over the next 6 h to an average concentration of 0.128 +/- 0.065 mg/L. The terminal half-life (T1/2) was 1.0 +/- 0.17 h, the systemic clearance (CI) was 5.50 +/- 1.06 mL/min/kg and the volume of distribution (Vss) was 0.378 +/- 0.073 L/kg. The extrapolated area under the curve (AUC0-x) was 0.903 +/- 0.127 mg/mL x min; the area extrapolated past the last (6 h) data point to infinite time averaged only 1.25% of the total AUC0-x. The kidneys had the greatest accumulation of Pt (7.04 +/- 3.006 microg/g), followed by the liver (3.08 +/- 1.785 microg/g DM). CONCLUSIONS AND CLINICAL RELEVANCE: Carboplatin infusion in sulphur-crested cockatoos produced mild, transient alimentary tract signs and the Pt plasma concentration was similar whether carboplatin was given intravenously or intraosseously. Filterable plasma Pt concentrations for carboplatin persisted longer than for cisplatin, due mostly to the difference in systemic clearance between these drugs in sulphur-crested cockatoos. The distribution of tissue Pt after carboplatin administration was similar to that reported for cisplatin in sulphur-crested cockatoos. Despite anatomical, physiological and biochemical differences among animal species, the pharmacokinetic disposition of filterable Pt in the sulphur-crested cockatoo shares some features with the kinetics reported previously in other animals and human beings.

Animals↗
PubMed1998

Unguided bronchoalveolar lavage techniques and residual effects in dogs.

OBJECTIVES: To investigate the use of unguided bronchoalveolar lavage techniques in dogs without fibreoptic bronchoscopy, using an adapted single vascular catheter and a double-lumen catheter made from two single vascular catheters. ANIMALS: Sixty-nine dogs were examined with the single-catheter technique and 110 dogs with the double-catheter technique. DESIGN: A prospective study. PROCEDURE: Sixty-nine and 220 samples, collected with the single catheter and the double catheter respectively, were examined cytologically. Lungs of 69 dogs were examined grossly and histologically. Radiographic examination was performed on 11 dogs. RESULTS: The double-catheter technique produced samples with significantly higher cellularity (P < 0.01) and fewer red blood cells (P < 0.01) than the single-catheter technique. Repeat samples collected with a double catheter were not significantly different (P > 0.01) in any value. A reference range for nucleated cell counts of 62 to 1210 x 10(6)/L was calculated from 57 clinically and histologically normal dogs. The major residual effects of the technique were localised pulmonary oedema, and alveolar distension with collapse and congestion of distant parenchyma. Thoracic radiographs revealed increased lung opacity for at least up to 7 h after the procedure. CONCLUSIONS: The cellularity of the bronchoalveolar lavage fluid obtained was adequate and sufficient fluid was retrieved when the single catheter was located in a proper position. However, the double catheter obtained better samples more quickly and easily, with less damage to the respiratory tract.

Animals↗
PubMed1998

Investigation of osteochondrosis in grazing beef cattle.

Severe lameness attributed to osteochondrosis is described in an extensively managed Brahman herd grazing on improved native pasture. Clinical signs were observed in five animals, three of which were necropsied. The most prominent lesions were in the elbow and stifle joints. There were multiple fissuring and ulceration of thickened articular cartilage with numerous osteochondral bodies present in the joint spaces. All affected animals were entire males sharing a common ancestral sire. Inheritance and gender were suspected to be contributing factors in the development of the disease.

Animals↗
PubMed1996

The effects of allopurinol on the ultrastructure of ischaemic and reperfused large intestine of sheep.

OBJECTIVE: To test the possible inhibitory effect of allopurinol on reperfusion injury, caused by oxygen-derived free radicals, of sheep large intestine. DESIGN: An ultrastructural study on caecal tissues from control and treated groups. ANIMALS: Fifty sheep in four ischaemic and reperfused (treatment) groups and one control group. Three of the treatment groups were subdivided for half to be injected with allopurinol and the other half with its solvent, potassium hydroxide (KOH). PROCEDURE: Ischaemia of the caecum was induced in the four treatment groups for 60 minutes by clamping the apex. Allopurinol and its KOH solvent were injected intravenously in three treatment groups prior to ischaemia. Samples were collected before and 1 hour after induction of ischaemia and 1 min, 1 h and 8 h after reperfusion. Tissues were processed and examined with an electron microscope. RESULTS: Untreated and solvent injected sheep showed minor ultrastructural changes following ischaemia. With reperfusion, there was severe mitochondrial, goblet cell and basement membrane damage. Tissues from allopurinol-treated sheep were preserved and appeared similar to tissues from the control group. CONCLUSION: Pre-treatment with allopurinol prevented damage to tissues whereas untreated or allopurinol solvent-treated showed severe damage following reperfusion. It is believed that allopurinol, an analogue of hypoxanthine and xanthine, prevents reperfusion injury by competitively binding with xanthine oxidase. This reduces or inhibits the xanthine oxidase mediated conversion of hypoxanthine to xanthine thereby preventing the formation of oxygen-derived free radicals.

Allopurinol↗
PubMed1992

Volvulus of the colon in a horse associated with a mesocolic-umbilical band.

A 7-years-old Clydesdale mare was presented with severe abdominal distension and acute colic. Dilated large intestine was palpated per rectum and a ventral midline exploratory laparotomy was performed. A 180 degrees volvulus of the pelvic flexure was present, associated with an inelastic band of tissue connecting the mesocolon to the umbilicus. The band was ligated and transected, and the volvulus reduced. Postoperative complications included hyponatraemia, metabolic acidosis and laminitis. The possible aetiology of the mesocolic-umbilical band is discussed.

Animals↗
PubMed1989

The effect of infusions of microfilariae (L1 larvae) of Dirofilaria immitis in dogs.

Four pups were given three intravenous infusions of microfilariae over a 7-month period to determine if radiographic changes could be detected in the lungs while sensitivity to first stage microfilariae was being induced. Mild pathological changes occurred but these could not be detected on any of the radiographs. Radiographic changes described by others and 'Eosinophilic lungs' did not result from the immune response to the first stage larvae.

Animals↗
PubMed1988

Pulmonary changes associated with dead filariae (Dirofilaria immitis) and concurrent antigenic exposure in dogs.

Initially, a group of 5 dogs had their left pulmonary artery ligated 7 months prior to the insertion of filariae (Dirofilaria immitis). A second group of 3 dogs was used as controls for the various components of the experiment. Antigen (D. immitis) was injected subcutaneously on 3 occasions and necropsy was performed 5 weeks after insertion of filariae. These results were then compared to those from the control dogs. With exposure to antigen, severe pulmonary arterial and parenchymal disease was produced in association with the insertion of dead D. immitis filariae into the pulmonary artery. In the dogs receiving antigen, the arterial and peri-arterial pathology was generally more intense and at a more advanced stage of organization than in the control animals. Interstitial pneumonitis was also more prominent in the antigen-stimulated dogs. The advanced nature of the reaction was also reflected in the skin histology of the injection sites. The pathology was similar to that reported for natural dirofilariasis and it appears that most of the pathology of dirofilariasis is associated with reactions to dead filariae or filarial by-products and concurrent antigenic experience.

Animals↗