Biomedical subjects

M Butt

Publications and source records attributed to M Butt.

16 recordsLinked to original sources

PubMed1993

Engraftment of bovine leukemia virus infected lymphocytes into SCID mice.

SCID mice inoculated with peripheral blood lymphocytes from a tumor-bearing BLV-positive cow developed lymphosarcomas after 6 months. DNA from the splenic tumor specifically hybridized with a bovine Sstl satellite probe, showing that these tumor cells were of bovine origin. The clonality of the SCID splenic tumor, as measured by the integration pattern of BLV proviruses, was the same as that in the donor lymphocyte population.

Animals↗

PubMed1993

Effects of aspirin on human auditory filters.

Auditory filter shapes were measured in eight male volunteers with normal hearing, using a notched-noise forward-masking paradigm and a signal frequency of 4 kHz. The measurements were made under three conditions: after listeners had taken eight doses of three 320 mg aspirin tablets every six hours; after an identical schedule of placebo ingestion; and one week after testing in the first two conditions had been completed. Half of the listeners did the placebo condition first, and half did the aspirin condition first. Aspirin and placebo were administered double-blind, and testing took place approximately one hour after the last dose. Filter shapes were significantly broader in the aspirin condition than in the placebo and post-test conditions, indicating that even a modest dose affects auditory frequency selectivity. Two-point measures of growth of masking did not differ significantly between conditions.

Acoustic Stimulation↗

PubMed1991

Xanthine oxidase formation during experimental ischemia of the equine small intestine.

We hypothesized that xanthine oxidase plays a role in the postischemic reperfusion injury in the equine small intestine. Under anesthesia, four horses and two ponies underwent ischemic strangulating obstructions of segments of the proximal jejunum, mid-jejunum and ileum. Prior to vascular occlusion, and at 1 h and 2 h of ischemia, full-thickness intestinal biopsies were collected for histopathological evaluation and for determination of combined xanthine dehydrogenase (XDH) plus xanthine oxidase (XO) activity, and XO activity alone. The level of XO activity was expressed in percentage according to the ratio of XO/(XDH + XO). We found a nearly threefold increase in the combined level of XDH plus XO activity from ileum to duodenum (p less than 0.04). However, the preischemic level of % XO activity did not vary significantly (p = 0.61) between segments of jejuno-ileum. Likewise, no significant difference was noted between intestinal segments after ischemia. Therefore, the data from all intestinal segments were pooled for each time and analyzed using Wilcoxon's signed rank test (one-tailed). Compared to the pre-ischemic level of % XO activity (median 27%), the % XO activity increased after 1 h of ischemia (median 37.0%), reaching statistical significance (p = 0.016). There were no statistical differences between the preischemic % XO activity and the % XO activity in non-ischemic bowel at the end of the anesthetic period. During ischemia, % XO activity increased, which lends credence to the importance of xanthine oxidase in previously-documented reperfusion injury in the equine small intestine.

Animals↗

PubMed1990