Search PubMed⌕ Search

Biomedical subjects

G Mikhail

Publications and source records attributed to G Mikhail.

At least 37 records · Page 2Linked to original sources
PubMed1979

Free and protein-bound steroids in amniotic fluid of midpregnancy.

Ninety-seven amniotic fluid (AF) specimens, 67 with male fetuses and 30 with female fetuses, were obtained by amniocentesis at 14 to 18 weeks of gestation for analysis of free and protein-bound estrone (E1), estradiol (E2), androstenedione (A), testosterone (T), and progesterone (P). Ten maternal plasma (MP) samples of comparable gestational age were analyzed for the same free and protein-bound steroids. Significantly lower total E1, E2, A, and T, but not P, levels were found in AF when compared to MP. The percentage of free steroids was higher in AF than in MP, while the percentage of specific protein-bound steroids was lower in the AF than in MP. Free (unbound) steroid levels of E1 and P were higher in AF than in MP, whereas levels of E2 were lower in AF than in MP. The free A and T levels in MP were lower than in AF with male fetuses, yet higher than in AF with female fetuses. Possible biologic activity of steroids in this fluid may depend on the dynamic balance between the free, the specific protein-bound, and the nonspecific protein-bound steroids.

Adult↗
PubMed1979

Daily plasma prolactin in various gynecologic endocrinopathies.

Daily plasma prolactin levels were measured in women with various gynecologic endocrinopathies in order to compare mean levels and variations over the sampling interval with prolactin levels in women with normal ovulatory cycles. The normal-cycle mean prolactin level was 14.7 ng/ml +/- 1.4 (SE). Levels greater than 42 ng/ml, 2 SD above the mean, were considered abnormal. Patients with endocrinopathies were classified as "normoprolactinemic" if the mean prolactin level was less than 42 ng/ml and less than 12% of the daily values peaked to greater than 42 ng/ml. An "intermediate" group was defined in which the mean prolactin level was less than 42 ng/ml but more than 12% of daily values peaked to greater than 42 ng/ml. Those patients whose mean prolactin levels were greater than 42 ng/ml were considered "hyperprolactinemic". Significant differences were noted when mean prolactin levels were compared with normal-cycle levels in 16 or 18 women with various gynecologic endocrinopathies. The need for repeated prolactin sampling in certain clinical situations, as well as the possibility that a "critical" prolactin level is necessary for normal ovarian function, is discussed.

Anovulation↗
PubMed1979

Plasma hormone profile in anovulation.

Daily plasma hormones, including luteinizing hormone (LH), follicle-stimulating hormone (FSH), estrone (E1), estradiol (E2), progesterone, androstenedione, and testosterone (T), were measured in 16 anovulatory patients for a span of 3 to 4 weeks. The clinical diagnoses in this group of patients included the following: anovulation-eumenorrhea (n = 5), anovulation-polymenorrhea (n = 1), anovulation-oligomenorrhea (n = 3), congenital adrenal hyperplasia (n = 1), polycystic ovarian disease (n = 4), severe hypothalamic amenorrhea (n = 1), and postpartum amenorrhea-galactorrhea (n = 1). Follicular activity was evident in polymenorrheic and oligomenorrheic patients, and menstruation occurred in these patients following estrogen withdrawal. No follicular maturation was noted in the group of patients with anovulation-eumenorrhea, and menstruation in these patients was considered breakthrough bleeding. Low FSH levels were observed in anovulatory patients with eumenorrhea, polymenorrhea, and oligomenorrhea. Significantly high LH values were noted in both classic and non-classic polycystic ovarian disease. Extremely low E1 and E2 levels were found in patients with severe hypothalamic amenorrhea and postpartum amenorrhea-galactorrhea. Slightly elevated progesterone levels were observed in polymenorrheic and oligomenorrheic patients prior to menstruation; this was frequently associated with an LH surge or elevation. Elevated T levels were consistently associated with hirsutism but not with obesity.

Adolescent↗
PubMed1976

Free and protein-bound plasma estradiol-17 beta during the menstrual cycle.

Methods are described for the measurement of the estradiol-binding capacity of TeBG and of the free, TeBG-bound, and non-specifically protein-bound fractions of plasma estradiol. Each determination used undiluted plasma at 37 C, and a total volume of less than 2.0 ml of plasma was required to complete all the assays. The measurement of the per cent of free estradiol was affected by changes in plasma dilution. The measurement of the other fractions of estradiol was not influenced by changes in either the dilution or the volume of plasma. The distribution of plasma estradiol was determined daily throughout 5 individual menstrual cycles. The per cent of free, the per cent of TeBG-bound, and the TeBG binding capacity of estradiol remained constant throughout the cycle with mean values of 2.21 +/- 0.04% (SE), 38.4 +/- 0.7%, and 16.6 +/- 0.43 ng/ml, respectively. The mean association constant of TeBG for estradiol was 6.58 +/- 0.25 x 10(7)M-1. The concentration of the free and non-specifically protein-bound fractions of estradiol paralleled the total plasma concentration of estradiol. The results show that biologic events related to normal cyclic changes of plasma estradiol may be attributed to fluctuations in the free estradiol and to estradiol which is bound with low affinity to non-specific plasma proteins.

Estradiol↗
PubMed1976

Progesterone binding in rabbit oviduct and uterus.

Progesterone binding of high affinity with a dissociation constant of 10(-9) M was identified in cytosol of rabbit oviduct and uterus. Macromolecules with sedimentation coefficients of 7-8 S and 4-5 S were present. Progesterone receptor concentration was two to fivefold lower in the oviduct when compared with the uterus. The receptor concentration declined steadily from 3 hr until 144 hr after mating in the uterus; however, the decline in oviductal receptor was not significant until the sixth day of pregnancy. Progesterone receptor concentration in rabbit oviduct and uterus in estrus and early pregnancy was greater than estradiol receptor levels.

Animals↗
PubMed1975

Progesterone receptor of the human myometrium.

A progesterone binding protein was characterized in the cytosol of human myometrium. The receptor sedimented in the 4S region on sucrose gradients and had an equilibrium dissociation constant of 3.7 times 10-9M. Synthetic progestagens had an affinity equivalent to that of progesterone while cortisol had low affinity for the binding protein. These same progestagens showed very low binding to human CBG. In normally cycling women, the total levels of cytosol receptor were higher during the follicular phase than during the luteal phase. Subjects taking oral contraceptives and those who were pregnant had the lowest concentration of myometrial progesterone receptor. Postmenopausal women had levels of myometrial receptor lower than those of the secretory phase of the cycle. Estrogen therapy increased the receptor concentrations of the menopausal myometrium to those of the proliferative phase. The estradiol receptor levels of myometrial cytosol revealed similar changes in cycling women. When both binding proteins were measured concurrently in the same specimen, there was a significant positive correlation.

Anovulation↗
PubMed1975

Hormonal changes associated with Danazol therapy.

During a 6-month course of treatment of endometriosis with Danazol, a synthetic derivative of 17alpha-ethinyl testosterone, the following hormonal changes were found. Plasma LH remained essentially unchanged but FSH concentration was consistently in the low normal range. Plasma estradiol, especially after the fourth week of therapy, dropped to levels that did not exceed 30 pg/ml throughout the 6-month period of therapy. Plasma progesterone concentration was consistent with follicular phase levels. In the months after discontinuation of Danazol, all hormone parameters were strongly suggestive of normal ovulatory cycles. Danazol did not displace estradiol bound by endometrial cytosol.

Alkynes↗