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Biomedical subjects

S T Shaw

Publications and source records attributed to S T Shaw.

At least 37 records · Page 2Linked to original sources
PubMed1981

Role of prostaglandins in IUD-associated uterine bleeding--effect of a prostaglandin synthetase inhibitor (ibuprofen).

Prostaglandins have been shown to be increased in the endometrium of women and experimental animals wearing intrauterine devices (IUDs). As prostaglandins may cause increased vascularity and vascular permeability, and as certain prostaglandins (PgI2) inhibit platelet activity, the local generation of prostaglandins may contribute to endometrial bleeding. Thus, the effect of ibuprofen, a prostaglandin synthetase inhibitor, was tested by quantifying menstrual blood loss in 20 women wearing IUDs in a double-blind, 2-period crossover study. Ibuprofen produced a significant reduction in menstrual blood loss; the percentage reduction was greater in women using a Lippes Loop and who had heavier blood loss (39%) than in women using a copper device and who had lighter blood loss (25%). These findings support the contention that prostaglandin synthesis is important in the genesis of IUD-associated menorrhagia and that prostaglandin inhibitors may be useful in the therapy of this condition.

Adult↗
PubMed1980

Tritiated water exchange in the human uterine cavity.

Measurements with the use of tritiated water (3H2O) in human volunteers indicate that the mean tritiated water half life (t1/2 3H2O) in the uterine cavity is 1.3 minutes. This figure is very close to that previously measured in subhuman primates. By extrapolation from various prior studies the volume of the human uterine cavity (aVc) may be assumed to approximate 0.4 to 0.6 ml. According to the formula aVc divided by 2 x 1,440 divided by (t1/2 3H2O) water turnover in the human endometrial canal is calculated to range from 222 to 332 ml/24 hours.

Adult↗
PubMed1980

Comparison of metabolic and clinical effects of four oral contraceptive formulations and a contraceptive vaginal ring.

A group of 100 women desiring OC received one of the following four formulations on a randomized basis: (1) mestranol 50 micrograms and norethindrone 1 mg, , (2) ethinyl estradiol 50 micrograms and norethindrone 1 mg, (3) ethinyl estradiol 35 micrograms and norethindrone 1 mg, and (4) ethinyl estradiol 30 micrograms and levonorgestrel 150 mg. An additional 10 women received a CVR containing levonorgestrel and estradiol. Measurement of a large number of serum chemistries, lipids, proteins, clotting factors, and liver enzymes was obtained before and 3 and 6 months after starting medication. Clinical factors such as weight, blood pressure, bleeding or spotting, or any adverse side effects were also recorded. There was no significant difference in the metabolic parameters measured among the four oral contraceptives except the increase in angiotensinogen was slightly less in the groups receiving the compounds with 30 or 35 micrograms estrogen and the groups receiving the norgestrel compound had no increase in triglycerides and a slight decrease in cholesterol levels. When the CVR was compared with all oral contraceptives it was found to produce no change in angiotensinogen levels and a decrease in triglycerides. Some of each group of OC users had a lowering of antithrombin III to abnormal levels but none of the CVR users had his amount of decrease. As oral steroids with 30 or 35 micrograms of estrogen do not produce significantly less metabolic alteration than do compounds with 50 micrograms of estrogen, it is unlikely that their use will reduce the incidence of the uncommon serious adverse effects associated with OC use. However, since the CVR's did not increase angiotensinogen, their use as contraceptives will most likely not produce hypertension and possibly the other serious circulatory problems which are increased in some OC users.

Adolescent↗
PubMed1979

Vessel density in endometrium of women with and without intrauterine contraceptive devices: a morphometric evaluation.

Increased vascularity was found in the endometrial functionalis in uteri of women wearing intrauterine contraceptive devices (IUDs) as compared to uteri of women without IUDs (control subjects). Vessel concentration was highest in endometrial tissue adjacent to that tissue which was depressed by the IUD. In control tissues there was a significant variation in vascularity according to geographic location in the following order of magnitude: fundus greater than corpus greater than cornua greater than isthmus. No significant variation was found, however, among different phases of the ovarian cycle in either control or IUD cases. Increased endometrial vascularity could be a reaction to vessel damage caused by the IUD and for several reasons may contribute to IUD-induced endometrial bleeding.

Arterioles↗
PubMed1979

Effect of prior pregnancy and combined oral contraceptives on baseline menstrual blood loss and bleeding response to intrauterine devices.

No effect of pregnancy was found on baseline menstrual blood loss (MBL) in women within one year of parturition or abortion. The increased bleeding response of women to intrauterine devices (IUDs) was found to be independent of pregnancy status during the year preceding IUD sertion. Women pregnant within a year of insertion had no different MBL than those pregnant more than a year prior to insertion. MBL quantified in subjects within three months of discontinuing combined oral contraceptives (OCs) was significantly lower than in prior non-OC users. Furthermore, MBL was significantly reduced in the former group during the first three menses following IUD insertion. At the sixth and twelfth menses post-insertion, MBL was still lower in prior OC users, but the difference between users and non-users was less and no longer statistically significant.

Contraceptive Devices, Female↗
PubMed1979

Morphologic studies on IUD-induced metrorrhagia. I. Endometrial changes and clinical correlations.

Morphologic studies on human hysterectomy specimens indicate the IUD elicits a vascular reaction which is most pronounced in the endometrium adjacent to the device. This reaction includes increased vascularity, congestion and increased permeability, and degeneration with defect formation. In addition, there is poor hemostatic responsiveness to vascular permeability and damage. The reaction leads to interstitial hemorrhage which undoubtedly causes metrorrhagia. A likely cause for initial vascular damage is mechanical stress transmitted by the IUD through the endometrium to its vascular network. Vascular reaction and poor hemostatic responsiveness may be perpetuated during each cycle by the products released from endothelial cell degeneration and necrosis. Bleeding is one of the most frequent complications leading to discontinuation of an otherwise effective form of long-term contraception and family spacing. Therefore, its solution could be of crucial importance to world-wide population control. Our findings suggest that better understanding of the mechanism of IUD-induced metrorrhagia should result from closer study of the endometrium adjacent to that which is compressed by the IUD.

Endometrium↗
PubMed1979

Morphologic studies on IUD-induced metrorrhagia. II. Surface changes of the endometrium and microscopic localization of bleeding sites.

Surface changes were extensively studied by light and electron microscopy in human endometrium exposed to IUD's. A wide variety of alterations in the covering epithelium and its basal lamina (basement membrane) was observed. These ranged from essentially no alteration to a covering basement membrane completely denuded of its epithelium. Erosions or discontinuities of the surface basement membrane were uncommon, and when they occurred were most often associated with extrusion of fluid and cellular elements from the stroma into the uterine lumen. Metrorrhagia associated with IUDs probably results from two basic types of hemorrhage through the endometrial surface. Tissue adjacent to the IUD with interstitial hemorrhage bleed into the uterine cavity by (1) red cell transmigration through surface membranes (surface epithelium and its basal lamina), and (2) high interstitial pressure breaks in these same membranes.

Basement Membrane↗
PubMed1975

Effective body water half-life and total body water in rhesus and cynomolgus monkeys.

Although body water content and effective water half-life have been determined in several mammalian species, including man, these measurements are not available for sub-human primates to our knowledge. Values were therefore determined in a group of rhesus and cynomolgus monkeys. A fairly wide range of water half-life values was found in each of the two species between animals, but there was little variation within animals who had more than one determination over the course of 1 year. Mean values for effective water half-life were 7.2 days and 3.7 days for naturally menstruating females of the cynomolgus and rhesus species, respectively. Water half-life in female rhesus monkeys with artificial menstrual cycles averaged 6.2 days. Females of both species had a similar percentage of body water content of 64%. Water half-life measured 7.1 and 8.5 days in two male rhesus; and water content was 62% of body weight in one of these animals.

Animals↗
PubMed1975

3H2O volume and exchange in uterine cavity of monkeys.

A technique was developed to measure water exchange in the endometrical canal (uterine cavity). This type of determination should provide information necessary to understanding intrauterine pharmacokinetics. In the study described, measurements were performed on one cynomologus and four rhesus monkeys. Endometrial fluid in the uterine cavity was replaced with a 3H2O solution of known specific radioactivity (dpm/ml). Radioactivity remaining in the cavity at measured intervals of approximately 0.5, 1, 2, and 3 min following replacement was determined by flushing out the cavity. By extrapolating the 3H2O disappearance curve versus time to t = 0 (zero time), the apparent cavity volume (aVc) was derived. Values for aVc and t 1/2 3H2O were used to calculate endometrial fluid-water turnover rate. Mean values determined in four rhesus monkeys were as follows: aVc, 0.032 ml; t 1/2 H2O, 1.17 min; 24-h H2O turnover, 19.5 ml. In general, this value for H2O turnover was considerably higher than values of endometrial fluid production quantitated by other techniques. Water measurements in human uteri similar to those reported here appear feasible and are anticipated in future work.

Animals↗