Biomedical subjects
Publications and source records attributed to A D Watson.
A 4-year Basset bitch with a 9-week history of depression, lethargy, inappetence and weight loss was found to have azotaemia, hypercalcaemia and hyperphosphataemia. Laparotomy and kidney biopsy revealed end-stage renal disease and the dog was killed. Hyperplasia of all 4 parathyroid glands was found at autopsy. The presumptive diagnosis was idiopathic renal failure with resulting tertiary hyperparathyroidism.
Explore the source record for details and available documents.
Six cats were given chloramphenicol orally at the dose level of 120/mg/kg/day in 3 divided doses for 14 days and were then observed for another 3 weeks after treatment. Five other cats were used as untreated controls for the first 14 days and subsequently were given 60 mg of chloramphenicol/kg/day for 21 days. Clinical signs of toxicosis, which were more severe in cats given the higher dose level, included central nervous system depression, dehydration, reduced food intake, body weight loss, sporadic diarrhea, and vomiting. In cats given the higher dose level, chloramphenicol caused reversible marrow suppression, with marrow hypoplasia, maturation arrest of erythroid cells, and inhibition of mitotic activity, and caused vacuolation of lymphocytes and of early myeloid and erythroid cells. Significant changes were evident in bone marrow after treatment for 1 week and in peripheral blood at the end of the 2nd week. Hematologic changes included decreased numbers of neutrophils, lymphocytes, reticulocytes, and platelets. In cats given the lower dose level, changes in blood and bone marrow were similar but less severe.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
On separate occasions, five fasted adult greyhounds were dosed orally with 50 mg chloramphenicol/kg, both alone and in conjunction with other drugs. The same five dogs were later given 50 mg chloramphenicol/kg when fed ad lib. Chloramphenicol levels in plasma were determined at intervals after dosing. The intial plasma chloramphenicol levels were higher when the drug was administered concurrently with calcium lactate tablets (50 mg/kg) or a proprietary enteric mixture containing kaolin, pectin, aluminium hydroxide and belladonna extract. Lower plasma levels resulted when the antibiotic was given with dry extract of belladonna (20 mg/dog) or intravenous chlorpromazine (2 mg/kg). There was no significant effect with coated ferrous gluconate tablets (30 mg/kg). Feeding ad lib increased the initial chloramphenicol levels, but produced lower levels subsequently.
Twenty dogs were given chloramphenicol by mouth night and morning for 14 days: six dogs were dosed at 225 mg/kg/day, four each at 175 and 125 mg/kg/day and three each at 275 and 75 mg/kg/day. Six control dogs were given empty gelatin capsules twice daily for the same period. Dogs dosed at 75 mg/kg consumed more food and gained a little more weight than the control dogs, while those in the 175, 225 and 275 mg/kg groups ate less and lost weight. Four dogs dosed at 175 mg/kg or above became dull and depressed and virtually ceased to eat. No changes were observed in erythrocyte and reticulocyte counts, haemoglobin concentration, packed cell volume or total and differential leukocyte counts during the experiment. Bone marrow examination showed suppression of erythropoiesis in four of nine dogs dosed at 225 or 275 mg/kg/day. In addition, there was evidence of decreased mitotic activity and reduced rate of granulocytopoiesis in the 275 mg/kg group. Vacuolation of marrow cells was not observed. The two toxic effects observed (depression and hypophagia on the one hand, marrow suppression on the other) occurred separately or together in individual dogs.
From June 1971 to June 1972, sera from 600 dogs in Sydney were tested for leptospiral agglutinins by a rapid slide agglutination method. The end-point titre was taken at 50 percent agglutination of the live organisms. Forty-one samples (6.8 percent) had a significant leptospiral titres (100 or greater) and 5 of these reacted to 2 serotypes. Thirty serums (5 percent) contained agglutinins against L. copenhageni, and 6 (1 percent) against L. pomona, while a few samples reacted against hardjo, tarassovi, australis, grippotyphosa or pyrogenes serotypes. No significant titres were found to L. canicola, L. hebdomadis, L. autumnalis or L. bataviae.
Chloramphenicol concentrations were assayed chemically in tissue homogenates, blood, and certain extravascular fluids of Greyhounds killed 1.5, 3, 6, and 12 hours after they were orally given the drug (50 mg/kg). The concentrations of hemoglobin in blood and tissue homogenates were used to estimate "corrected values" to allow for differences in vascularity of the tissues sampled. The distribution of chloramphenicol in the body was not uniform. In all sampled tissues except brain, the initial corrected values were higher than the concentrations in blood. The tissues sampled, in diminishing order of initial corrected value, were lymph node, spleen, pancreas, liver, kidney, lung, muscle, and brain. The persistence of antibiotic in different tissues varied, and in some tissues it was detectable when blood concentrations reached zero. Penetration of chloramphenicol into brain and cerebrospinal fluid was slower than in other tissues and fluids. In aqueous humor and cerebrospinal fluid, concentrations were lower than those in blood, but high concentrations were present in urine. The findings indicated that during chloramphenicol therapy it may be advantageous to select dosage frequencies according to the site of infection.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Erythrocyte aplasia was diagnosed in a 6-year-old dog which had severe non-regenerative anaemia with depletion of erythroid cells in the bone marrow but normal production of granulocytes and platelets. Treatment with blood transfusions, testosterone and dexamethasone was unsuccessful. The dog died 46 days after initial examination as a result of anaemia, transfusion reactions, and toxaemia from an ascending urinary tract infection.
A 4-year-old Scotch Collie bitch was presented for examination because of hyperthermia and anaemia. Haematological examination and bone marrow biopsy led to a diagnosis of myeloid neoplasia. At autopsy there was slight enlargement of the liver, spleen and some lymph nodes. Microscopic examination revealed extensive infiltration of these tissues by neoplastic myeloid cells.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.