Estrogen augments the vasodilatory effects of vascular endothelial growth factor in the uterine circulation of the rat.

OBJECTIVE: Pregnancy augments uterine artery vasodilatation in response to vascular endothelial growth factor, although the underlying mechanism is not known. The aim of this study was to test the hypothesis that estrogen and progesterone, the primary sex steroids of pregnancy, are responsible for this effect through increased endothelial secretion of nitric oxide. STUDY DESIGN: Adult female Sprague-Dawley rats underwent oophorectomy at 9 weeks of age with concomitant placement of 21-day timed-release pellets containing either 17beta-estradiol (n = 6) or progesterone (n = 6), or a combination of these (n = 6). Control rats also underwent oophorectomy but did not receive hormone replacement (n = 6). Two to 3 weeks after oophorectomy the rats were killed and the main uterine artery was dissected free, cannulated in an arteriograph, and pressurized to 50 mm Hg. After constriction with phenylephrine, concentration-response curves to vascular endothelial growth factor (0.1-20 nmol/L) were performed to compare arterial sensitivity to and maximal effects of vascular endothelial growth factor among the 4 treatment groups. Vessels were then treated with N omega-nitro-L -arginine (0.24 mmol/L), an inhibitor of nitric oxide synthase, and the maximally effective concentration of vascular endothelial growth factor was reapplied to evaluate the relative contribution of nitric oxide to the overall effect. RESULTS: Comparisons of the effective concentration of vascular endothelial growth factor that elicited 50% of the maximal dilatation revealed the vessels of the estrogen group to be approximately 10 times more sensitive than the control group (0.4 +/- 0.11 nmol/L vs 4.2 +/- 1.13 nmol/L, respectively; P <. 05). Responses of vessels from the progesterone and combined groups were intermediate (progesterone, 2.3 +/- 0.66 nmol/L; combined, 1.1 +/- 0.28 nmol/L). Maximal vasodilatory responses were greatest in the groups with treatment including estrogen (estrogen, 61% +/- 3. 1%; combined, 54% +/- 3.4%; progesterone, 42% +/- 5.8%, control, 40% +/- 3.5%; P <.05). Addition of N omega-nitro-L -arginine inhibited maximal vascular endothelial growth factor-induced dilatation by approximately 40% irrespective of treatment group. CONCLUSION: The presence of estrogen rather than progesterone leads to an enhancement of vascular endothelial growth factor-induced arterial dilatation during pregnancy. This effect results from a proportional increase in endothelial nitric oxide secretion, along with that of another, as yet unidentified vasodilatory substance.

Transvaginal ultrasonographic diagnosis of uterine septa.

OBJECTIVE: To ascertain the sensitivity of transvaginal ultrasound as a screening tool in diagnosing patients with uterine septa. STUDY DESIGN: In this descriptive, retrospective study, the medical records of all patients who had hysteroscopic resection of uterine septa between 1990 and 1996 were reviewed. Specific preoperative imaging techniques were noted, and the sensitivity of transvaginal ultrasonography in correctly identifying the septum was calculated. RESULTS: During the seven-year period, 27 of 39 total patients undergoing hysteroscopic metroplasty had preoperative transvaginal ultrasonography. Twenty-two of the 27 ultrasonograms correctly identified the uterine septum, for a sensitivity of 81%. CONCLUSION: This was the largest study to date that specifically assessed the sensitivity of transvaginal ultrasonography as a reliable method of diagnosing uterine septa. It appears justifiable to use it as the initial screening tool for an accurate evaluation of uterine septa.

Ineffectiveness of latex condoms in preventing contamination of the transvaginal ultrasound transducer head.

The efficacy of condoms in preventing contamination of the transvaginal ultrasound transducer head and possible transmission of blood-borne pathogens is unknown. Our objective was to determine the rate of contamination of the transvaginal ultrasound probe after use in the emergency department. After indicated transvaginal ultrasound scans, the latex condom was removed and the transducer head was inspected for contamination. The presence of vaginal bleeding and the duration of the ultrasound scan were noted. Ten milliliters of hydrogen peroxide (H2O2) was placed in the condom. Bubbling, which occurs in the presence of blood or cervicovaginal secretions, was considered a positive test. Exposure of a clean condom or coupling gel to H2O2 did not cause bubbling. Two-tailed Fisher's Exact and Student's t tests were used for statistical analysis. Of 173 cases, 8 (5%) had a positive H2O2 test for contamination. In only 3 of these 8 cases was gross contamination seen. Latex condoms are ineffective in preventing contamination of the transvaginal ultrasound transducer head. Visual inspection of the transducer head often fails to identify the presence of blood or body fluids. This suggests that additional measures should be taken to prevent transmission of blood-borne pathogens.

Acquaintance rape and the high school student.

The purpose of this study was to determine the prevalence of forced sex among high school students and to assess student attitudes about it. The questionnaires were given in conjunction with a presentation on date rape to 9th through 12th grade students in health and science classes in three large metropolitan Louisiana public high schools. The first questionnaire, given before the presentation, elicited demographic information and attitudes about forced sex in 11 scenarios; the second, given after the program, asked if the student had ever been in a situation involving forced sex and, if so, whether he or she had told anyone. The two questionnaires were completed by all 237 students. Although one out of five students (20%) reported they had experienced forced sex, only half had told about the experience. A majority of boys (60%) found it acceptable in one or more situations for a boy to force sex on a girl. Male, black, and older students were significantly more likely (p < 0.05) to indicate that it was acceptable for a boy to force sex on a girl in certain circumstances. These findings should alert physicians to the risk of acquaintance rape among their high school student patients. Student attitudes, particularly those of males, may provide an important focus of preventive sex education in the physician's office, the classroom, and the community.