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C Shepherd

Publications and source records attributed to C Shepherd.

At least 19 recordsLinked to original sources
PubMed1999

Oxytocin and vasopressin constrict rat isolated uterine resistance arteries by activating vasopressin V1A receptors.

Both oxytocin and vasopressin cause potent and long-lasting vasoconstriction of uterine arteries from several species, including humans, and the resulting tissue ischemia is thought to be involved in the pathogenesis of primary dysmenorrhea. We have studied the effects of oxytocin and vasopressin in isolated resistance arteries (diameter, 90-120 microm) from non-pregnant rat uteri using two potent and selective receptor antagonists, SR 49059, a selective vasopressin V1A antagonist, and atosiban, a selective oxytocin antagonist. Uterine arteries with intact endothelium were mounted in a microvessel chamber, and pressurized to 75 mm Hg to allow the development of myogenic tone. Both vasopressin and oxytocin elicited a concentration-dependent vasoconstriction with a similar maximum effect (i.e., total vessel occlusion). The EC50 was 0.44 +/- 0.02 and 25 +/- 3.1 nM for vasopressin and oxytocin, respectively. Thus, vasopressin was 57-fold more potent than oxytocin. Schild analysis indicated that SR 49059 yielded a similar pA2 value against vasopressin-induced (pA2 = 8.96 +/- 0.60) or oxytocin-induced (pA2 = 9.06 +/- 0.23) contractions, suggesting that both agonists activated the vasopressin V1A receptor. In addition, atosiban (10(-7) M), a selective antagonist of the oxytocin receptor in the rat, did not antagonize the effect of vasopressin and oxytocin, showing that the oxytocin receptor is not involved in the response. In conclusion, these results suggest that V1A receptor stimulation is responsible for the vasoconstricting effects of both vasopressin and oxytocin in small diameter resistance arteries from the rat uterus.

Animals↗
PubMed1996

Incidence of secondary complications in spinal cord injury.

In order to document the incidence of secondary complications following spinal cord injury (SCI), data were collected from 348 patients with post-acute SCI. More than 95% of these patients reported at least one secondary problem, and more than half (58%) reported three or more. Statistical analyses indicated that, in general, the number and severity of complications varied with the time since injury. Obesity, pain, spasticity, urinary tract infections, and pressure sores were common. Issues of social integration were also identified. The results suggest that improvement is needed in practices related to prevention and follow-up.

Female↗