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Biomedical subjects

D R Stephens

Publications and source records attributed to D R Stephens.

7 recordsLinked to original sources
PubMed1998

Inaugural address.

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Cost Control↗
PubMed1993

Soft tissue reconstruction. Coverage of the chest wall and spine.

Advances in reconstructive surgery achieved during the past decade have considerably broadened the range of options available for coverage of the chest wall and spine. Flaps can be designed to maximize function and provide bulk, bony rigidity, sensation, or function, when needed. Local musculocutaneous and muscle flaps are preferred, but, at times, a free flap is more appropriate, either because the local tissue is inadequate or because a free flap best meets the needs of the recipient site. With current techniques, donor-site morbidity, flap survival, and, ultimately, patient outcome can be optimized to a much greater extent than in years past.

Humans↗
PubMed1987

Hormonal control of sexual and scent marking behaviors of male gerbils in relation to the sexually dimorphic area of the hypothalamus.

The sexual and scent marking behaviors of male gerbils are stimulated by testosterone (T) action in the preoptic area (POA) of the hypothalamus. The sexually dimorphic area (SDA) in the posterior POA, which also responds to T, is implicated in this process. This research studied the sensitivities of mating, marking, and the SDA to T metabolites and other steroids. Experiment 1 focused on mating. Male gerbils were implanted at castration with 2-mm Silastic capsules containing T, dihydrotestosterone (DHT), 19-nortestosterone (19-nor T), estradiol (E), or no hormone and were tested 3-7 weeks later. T, E, and 19-nor T maintained intromissions, but E-treated males rarely ejaculated. Controls and DHT-treated males stopped mounting. Experiment 2 compared the ability of these steroids to reinstate marking and mating using the same dose and a larger one (5 mm). Androstenedione, 19-hydroxytestosterone (19-OHT), and E plus DHT were studied as well. Volumes of the SDA and SDA pars compacta (SDApc) were also measured. Only T, 19-nor T, E, and E + DHT reinstated sexual behavior, but all steroids except 19-OHT stimulated marking. E and DHT synergized to elicit mating. For marking, they were no more effective together than alone. Steroid-treated males had larger SDAs than controls. Moreover, steroids that stimulated sexual activity produced larger SDAs than steroids that did not. SDA size correlated with copulatory rate, but not with copulatory efficiency. SDApc size correlated with copulatory efficiency, but not with copulatory rate. Like copulatory rate and efficiency, sizes of the SDA and SDApc did not correlate with each other.

Androgens↗