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Biomedical subjects

D R Kennedy

Publications and source records attributed to D R Kennedy.

5 recordsLinked to original sources
PubMed1978

Adrenergic influences on rabbit oviduct: effect of muscle size and ovarian hormones.

This study attempts to distinguish between a direct action of ovarian steroids on adrenergic neurons in the oviduct and an indirect effect mediated by changes in muscle size. Mature rabbits were treated as follows: group 1, ovariectomized and a polyethylene catheter (1 mm OD) inserted into isthmus of one oviduct (CT) with contralateral oviduct as control (C); group 2, normal, estrous animals with one intubated isthmus (ET) and contralateral control (E). Fourteen days postoperatively, oviducts were removed and muscle-wall thickness, norepinephrine (NE) content, and response to nerve stimulation were measured. Although castration atrophy was prevented in CT, NE content of CT was significantly less than C, 0.032 +/- 0.07 versus 1.09 +/- 0.10 nmol. NE content of ET was also significantly less than E (1.32 +/- 0.03 versus 1.81 +/- 2.0) despite a greater wall thickness of ET. It was concluded that: a) withdrawal of ovarian hormones reduces NE contents by a direct action on nerves; b) moderate stretch, per se, increases muscle size and reduces NE content; c) nerve stimulation induces muscle contraction despite large reduction in transmitter content.

Adrenergic Fibers↗
PubMed1977

The surgical treatment of retrocaval ureter.

Ureteric obstruction resulting from retrocaval ureter may be due to either compression of the ureter by the vena cava or stenosis of the postcaval segment. If obstruction is due to stenosis, the commonly described operation of division and anastomosis through the proximal dilated ureter or pelvis, after repositioning of the ureter, is likely to fail, as is division of the vena cava itself. Excision of the postcaval segment with anastomosis of the spatulated ureter over a Silastic splint is therefore recommended. Three case histories of patients with retrocaval ureter treated surgically are presented and support this view.

Adult↗
PubMed1977

Thyroid cold acclimation influences on norepinephrine metabolism in brown fat.

Norepinephrine turnover rates and tyrosine hydroxylase activities were determined in the interscapular brown fat pad of the rat during cold acclimation, hyperthyroxinism, and after thyroidectomy. Rats were cold acclimated by placement in a cold room, one rat to a cage, for a period of 6 wk. Hyperthyroxinism was induced by daily subcutaneous injections of L-thyroxine (1 mg/kg) for 6 days. Norepinephrine turnover rate and enzyme activity were determined at the end of each experimental period and at 8 wk after thyroidectomy. The rate of norepinephrine turnover increased during cold acclimation and hyperthyroxinism and decreased after thyroidectomy. Cold acclimation resulted in a significant increase in tyrosine hydroxylase activity, whereas no significant effect on enzyme activity was observed in hyperthyroxinism or after thyroidectomy. None of the conditions produced a change compared to controls in the apparent Km of tyrosine hydroxylase for L-tyrosine. Cold acclimation resulted in a significant decrease in the apparent Km of tyrosine hydroxylase for pterin cofactor, whereas thyroxine treatment and thyroidectomy had no effect.

Acclimatization↗