Search PubMed⌕ Search

Biomedical subjects

D J Yang

Publications and source records attributed to D J Yang.

94 records · Page 6Linked to original sources

Effect of ketamine enantiomers on sound-induced convulsions in epilepsy prone rats.

Epilepsy prone rats (Jobe et al, 1982) which had previously been determined to experience relatively mild seizures in response to a sound stimulus were used in this study in order to provide a model which would reveal either proconvulsant or anticonvulsant drug activity. Animals were administered dextrorotatory (+), levorotatory (-), or racemic (+/-) ketamine hydrochloride by intravenous (tail vein) injection and subsequently challenged with a 120 db broad spectrum sound stimulus. Evaluation of drug effect was based on presence/absence of seizure, seizure severity, and convulsive latency (time from onset of stimulus to onset of convulsive episode). Potencies relative to protection against seizure susceptibility were: (+) greater than (+/-) greater than (-), with the ratio of activity of the (+) and (-) isomers comparing to the ratio of activity found by other investigators relative to other effects produced by the isomers. Of all animals which were not fully protected, there were no instances of decrement of seizure severity. At low doses, there was a slight decrease in convulsive latency, which was the only indication of a proconvulsant effect. This effect is probably prevented at the higher doses by the anticonvulsant tendency of the drug.

Acoustic Stimulation↗

Preliminary study of cardiac accumulation of F-18 fluorotamoxifen in patients with breast cancer.

The clinical meaning of cardiac uptake of [18F]fluorotamoxifen was assessed. Tamoxifen, a nonsteroidal antiestrogenic drug for treatment and prevention of breast cancer, has a cardioprotective, estrogen-like effect in postmenopausal women. We conducted a pilot study of [18F]fluorotamoxifen to evaluate its clinical usefulness in patients with breast cancer. Significant cardiac uptake of [18F]fluorotamoxifen in five patients was found in the pilot study. We performed positron emission tomography (PET) with [18F]fluorotamoxifen. The intracardiac distribution of [18F]fluorotamoxifen was observed and compared with the patients' clinical symptoms, past history, and results of the electrocardiogram (ECG). None of the patients had a prior history of ischemic heart disease. Various patterns of [18F]fluorotamoxifen distribution were seen in the heart: one patient showed homogeneous distribution; two had defects in the lateral wall; one had patchy distribution; and in one the uptake was questionable. Non-uniform cardiac uptake may be related to myocardial damage. Cardiac uptake of tamoxifen suggests that its cardioprotective benefits may be related not only to serum cholesterol reduction but also to a direct cardioprotective action. Further experimental studies are required to elucidate the pathophysiological mechanism of cardiac uptake of [18F]fluorotamoxifen.

Adult↗