PubMed Health⌕ Search

Biomedical subjects

D Watt

Publications and source records attributed to D Watt.

30 records · Page 2Linked to original sources
PubMed1985

Determination of acute toxic effects in mice following exposure to methyl bromide.

An inhalation system was designed and constructed for acute nose exposure of mice to methyl bromide. Animals were exposed for 1 h to concentrations ranging from 0.87 to 5.93 mg/l. Mice exposed to concentrations up to 1.72 mg/l did not exhibit any indication of developing a toxic response. Animals exposed to concentrations to 2.20 and 2.70 mg/l exhibited significantly decreased lung and liver weights when compared to controls. Animals exposed to concentrations above 3.50 mg/l exhibited kidney lesions. At concentrations of 3.82 mg/l and above, animals exhibited abnormal clinical signs, weight loss, and mortality. In addition, at 4.70 mg/l, a liver lesion was observed. At concentrations above 5.77 mg/l, pathological changes were observed in the color and a decreased motor coordination was evident. Methyl bromide exposures of up to 3.82 mg/l did not affect the ability of mice to recall a single-task passive-avoidance test. The 1-h LC50 of methyl bromide in mice via inhalation was determined to be 4.68 mg/l (approximately 1200 ppm). The dose-response curve was quite steep and the LC10 to LC90 range of mortality was contained within a doubling of concentration.

Animals↗
PubMedDate not supplied

Morphine and etorphine: XIV. Detection by ELISA in equine urine.

We have raised antibodies to morphine and etorphine and developed one-step enzyme-linked immunosorbent assays (ELISA) for these drugs as part of a panel of post race tests for drugs in racing horses. These tests are simple, can be completed in 2 h, and can be read by visual inspection. The morphine ELISA has an I50 for morphine of about 1.5 ng/mL, while the etorphine ELISA has an I50 for etorphine of 250 pg/mL. Cross-reactivity studies show that the antimorphine antibody cross-reacts well with levorphanol, hydromorphone, and oxycodone, while the anti-etorphine antibody showed no cross-reactivity with buprenorphine, diprenorphine, oxymorphone, morphine, or thebaine. The morphine test readily detected parent morphine or its metabolites in equine urine for at least 8 h after administration of 50 mg/horse, while a 0.1 micrograms/kg dose of etorphine was detectable for up to 48 h post dosing. For each test the background activity in post-race urines was equal to or less than the I50 for the standard curves, making them useful equine forensic tests. Each of these tests has detected "positives" in post race urine samples and as such these tests are capable of substantially improving the speed and efficacy of both pre-race and post-race testing for morphine, etorphine, and their congeners in racing horses.

Animals↗
PubMedDate not supplied

Immunoassay detection of drugs in racing horses: detection of ethacrynic acid and bumetanide in equine urine by ELISA.

We have raised antibodies and developed one-step enzyme-linked immunosorbent assays (ELISA) for the diuretics ethacrynic acid and bumetanide as part of a panel of pre- and post-race tests for high potency drugs in racing horses. These ELISA tests are rapid (completed within one hour), sensitive, and can be read by eye. The ELISA detects ethacrynic acid at a drug concentration for half-maximal inhibition (I-50) of about 2.5 ng/mL for the parent drug. After dosing horses intravenously with 5 mg ethacrynic acid per horse, the parent drug or its metabolites are detectable in urine for at least 8 hours. The bumetanide ELISA has an I-50 for the parent drug of about 2.0 ng/mL and will detect bumetanide or its metabolites for about 8 hours in urine after intravenous administration of a 1.7-mg dose per horse. Both antibodies are relatively specific for each drug and do not cross-react with other commonly used diuretics or other acidic compounds often found in post-race equine urine samples. Ethacrynic acid and bumetanide are potent diuretics suspected of being illegally substituted for furosemide in certain racing jurisdictions. Development of these rapid, sensitive, and simple tests for these agents will allow more effective pre- and post-race control of the use of these agents in racing horses. Both tests have recently uncovered several "positives" for these medications in a midwestern racing jurisdiction.

Animals↗