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Biomedical subjects

R T Scott

Publications and source records attributed to R T Scott.

At least 19 recordsLinked to original sources
PubMed1992

Epidermal growth factor and its receptor in human implantation trophoblast: immunohistochemical evidence for autocrine/paracrine function.

Epidermal growth factor (EGF) and its receptor (EGF-R) were immunohistochemically localized in trophoblast during human implantation from intrauterine and ectopic pregnancies. EGF immunostaining was absent to light in the cytotrophoblast (CT), light to moderate in intermediate trophoblast (IT), and intense in the syncytiotrophoblast (ST). In ST, EGF immunostaining was found mostly in the cytoplasm; however, staining of the plasma membrane was also noted. Immunostaining for the EGF-R was absent to light in the CT and moderate to intense in the IT. Immunostaining for the EGF-R was intense in the ST, with moderate staining in the cytoplasm and intense staining in the plasma membrane. Staining was most intense on the microvilli of the ST. Additionally, EGF-R immunostaining could be demonstrated on nuclear membranes. The increase in the intensity of the immunostaining for both EGF and EGF-R noted in CT, IT, and ST suggests a differentiated expression of this receptor-ligand system in human trophoblast and provides evidence for an autocrine/paracrine role for EGF in trophoblast function. The presence of this receptor-ligand system during early human implantation strongly supports a role for EGF and the EGF-R in embryo-uterine signalling and the implantation process.

Embryo Implantation↗
PubMed1991

The window of embryo transfer and the efficiency of human conception in vitro.

Women with ovarian failure transferred with donated oocytes provide a unique in vivo model for the elucidation of the window of implantation and efficiency of reproduction in the human. Throughout 52 ovum donation cycles, the temporal window of endometrial receptivity was tested by replacing 2- to 12-cell embryos between days 16 and 24 of hormonally and histologically defined cycles. Of 37 transfers within days 17 to 19, 15 (40.5%) conceptions occurred. Twelve (32.4%) have reached viability. Of 11 patients transferred on days greater than or equal to 20, none conceived. Likewise, no pregnancies were achieved with 4 transfers on cycle day 16. Analysis of multiple embryo transfers within the suggested window of endometrial receptivity (days 17 to 19) revealed 14 of 24 (58.3%) to be conception cycles. considering only transfers with two or more embryos, at least one of which is of high quality (grades 1 to 2), yielded a 63.2% pregnancy rate. The results indicate a very high efficiency for in vitro fecundity provided optimal conditions are attained. The concepts leading to success in the ovum donation model should set the course for continued research toward improving results in other forms of assisted reproduction.

Abortion, Spontaneous↗
PubMed1991

Immunohistochemical localization of epidermal growth factor in human endometrium, decidua, and placenta.

Epidermal growth factor (EGF) was localized immunohistochemically in human endometrium throughout the menstrual cycle, in gestational decidua, and in first, second, and third trimester placenta using two polyclonal antihuman EGF antisera. In proliferative phase endometrium, moderate EGF immunostaining was localized to the cytoplasm of stromal cells, with absent to light staining of glandular epithelium. In the secretory phase, EGF immunostaining was intense and localized predominantly to stromal cells, particularly those surrounding spiral arterioles. There was absent to light EGF immunostaining within epithelial cells; however, there was no staining of subnuclear vacuoles. In addition, the luminal surface of exhausted secretory glands demonstrated moderate EGF immunostaining. In gestational decidua, EGF immunostaining was light to moderate in the stromal cells, but was intense in the surface epithelium. Intense EGF immunostaining was noted in the syncytiotrophoblast layer of first trimester placenta, with light to moderate staining of the cytotrophoblast. Immunostaining decreased in both layers of trophoblast as pregnancy progressed. Immunoreactive EGF is found in endometrium and trophoblast and may have a physiological role in endometrial and placental function.

Decidua↗
PubMed1991

Results of a prenatal screening program for the human immunodeficiency virus in a cross-sectional population.

A prenatal screening program for antibody to the human immunodeficiency virus (HIV) was examined prospectively in a cross-sectional population. Routine screening was performed on 3,241 women during the first trimester. Serum samples yielding repeatedly positive results on an enzyme-linked immunosorbent assay (ELISA) (n = 6) were subjected to confirmatory Western blot testing. All the specimens were determined to be false positive with atypical banding regions not consistent with HIV-1 infection. This false-positive rate was higher than in previous reports of screening programs in low-risk populations (P less than .005). Since antibody to HIV may not be detectable for several months after infection, we serially tested 984 of the women in different trimesters of pregnancy to determine whether repeat testing would yield seroconversion undetected at the first screening. No patient who initially tested negative on the ELISA tested positive later in gestation. We therefore recommend that routine screening be performed only once during pregnancy, preferably in the first or early second trimester, in the general population.

Adolescent↗
PubMed1991

Pharmacokinetics of percutaneous estradiol: a crossover study using a gel and a transdermal system in comparison with oral micronized estradiol.

The pharmacokinetics of three transdermal estradiol (E2) replacement regimens were studied following establishment of steady-state dynamics. Oestrogel 3.0 mg, Oestrogel 1.5 mg, and Estraderm transdermal delivery system 4 mg (0.05 mg/day) were administered for 14 days each to 15 postmenopausal volunteers, with a 14-day washout period between each regimen. The percutaneous E2 pharmacokinetics were compared with an oral micronized E2 preparation. Venous samples were obtained at 0, 1, 2, 4, 8, 12, and 24 hours on 3 sequential days 11 days after initial application of the Oestrogel and the transdermal delivery system, and at the same times after oral E2 ingestion. All three percutaneous regimens provided nearly constant serum E2 and estrone (E1) levels throughout their use. The mean serum E2 levels were 102.9 +/- 39.9, 68.1 +/- 27.4, and 41.1 +/- 13.5 pg/mL for Oestrogel 3.0 mg, Oestrogel 1.5 mg, and Estraderm, respectively. Oral E2 resulted in a mean serum E2 level of 114.0 +/- 65.2 pg/mL with marked peak and nadir values. The E1/E2 ratio was comparable with all three percutaneous regimens (1.08-1.33) and was significantly lower than that found with oral Estrace (5.05).

Administration, Cutaneous↗
PubMed1990

Transplacental transfer of zidovudine in the near-term pregnant baboon.

Approximately one third of infants born to human immunodeficiency virus type 1 seropositive mothers have evidence of infection or of acquired immunodeficiency syndrome by the age of 18 months. One fifth of infected infants also have died by age 18 months. This prevalence, combined with the demonstration that zidovudine (formerly azidothymidine) can decrease mortality and the frequency of opportunistic infections in patients with acquired immunodeficiency syndrome or acquired immunodeficiency syndrome--related complex, may lead to increasing use of azidothymidine in pregnancy despite a paucity of information regarding its pharmacokinetics. To further investigate the distribution of azidothymidine and its inactive metabolite 5'-glucuronide azidothymidine in the mother, fetus, and amniotic fluid, 12 near-term pregnant baboons were given oral azidothymidine (21 mg/kg/day in four divided doses every 6 hours, equivalent to the usual nonpregnant human dose of 1500 mg/day). Specimens of maternal blood, fetal arterial blood obtained by percutaneous umbilical cord blood sampling, and amniotic fluid were obtained after from one to 17 doses of azidothymidine. Azidothymidine levels were measured by radioimmunoassay with the INCSTAR commercial radioimmunoassay kit and using Escherichia coli beta-glucuronidase for determination of 5'-glucuronide azidothymidine levels. Paired analyses revealed significant concentration gradients between amniotic fluid, fetal serum, and maternal serum for both azidothymidine (p less than 0.019) and 5'-glucuronide azidothymidine (p less than 0.002). The amniotic fluid 5'-glucuronide azidothymidine level increased with increasing doses of azidothymidine despite the fact that the maternal azidothymidine and 5'-glucuronide azidothymidine concentrations were unchanged. This accumulation of amniotic fluid 5'-glucuronide azidothymidine may provide a functional drug reservoir and contribute to the higher fetal concentrations of the medication and its metabolite. Alternatively, the higher fetal levels may represent slower clearance in the fetus than in the mother. Further studies appear warranted with respect to possible adverse fetal effects, especially bone marrow suppression with prolonged and chronic exposure to azidothymidine.

Amniotic Fluid↗
PubMed1990

Intercycle variability of day 3 follicle-stimulating hormone levels and its effect on stimulation quality in in vitro fertilization.

Prior studies have demonstrated that gonadotropin stimulation quality and pregnancy rates are better in in vitro fertilization (IVF) patients with low basal cycle day 3 follicle-stimulating hormone (FSH) levels. The records of 81 patients who had undergone three or more IVF attempts during a 2-year period were studied to determine the degree and potential impact of intercycle variability in basal FSH concentrations. The mean of the individual standard deviations for all 81 patients was 4.2 +/- 0.4 mIU/mL. However, the patients with a mean basal FSH of less than 15 mIU/mL had a mean deviation of only 2.6 +/- 0.2 mIU/mL, whereas those with a mean basal FSH of greater than or equal to 15 mIU/mL had a mean deviation of 7.3 +/- 0.7 mIU/mL. Intercycle variability in basal FSH values did not predict changes in ovarian response to gonadotropin stimulation and thus may not be used to select an optimal cycle in which to stimulate an individual patient. Furthermore, patients with large intercycle variation responded poorly to gonadotropin stimulation independent of their basal FSH concentration. This information allows more precise counseling of patients regarding their appropriateness for assisted reproduction.

Animals↗
PubMed1990

Effects of leuprolide acetate on follicular fluid hormone composition at oocyte retrieval for in vitro fertilization.

The follicular fluid (FF) in 91 follicles from 17 women treated with leuprolide acetate (LA) before stimulation with gonadotropins for in vitro fertilization were analyzed for estradiol (E2), progesterone (P), androstenedione, prolactin, and human chorionic gonadotropin (hCG) and compared with the concentrations in 128 follicles from 31 women treated with gonadotropins alone. The FF E2 concentration in LA-treated patients was significantly lower than in non-LA patients for all oocyte maturational stages. Follicles containing metaphase II oocytes had significantly lower concentrations of P and hCG in LA-treated patients. These differences persisted when analysis was limited to follicles whose oocytes fertilized normally. These data indicate that in the presence of LA, normal oocyte maturation can occur despite lower intrafollicular concentrations of E2 and P.

Adult↗
PubMed1990

Non-functional ovarian cysts do not affect ipsilateral or contralateral ovarian performance during in-vitro fertilization.

Reports on the significance of ovarian cystic structures during in-vitro fertilization (IVF) have been conflicting. This study examined the effect of such structures on ovarian performance during IVF. Twenty-one patients with one or more cystic structures of 20-50 mm in diameter, detected on day 6 of the menstrual cycle, were compared to 35 non-cystic controls. Differences (cyst versus non-cyst) included basal oestradiol (E2) levels (40 +/- 4.8 versus 29 +/- 2.0 pg/ml; P less than 0.01), ampoules of gonadotrophins administered (24 +/- 2 versus 16 +/- 1; P less than 0.001) and peak E2 concentrations (415 +/- 45 versus 744 +/- 88 pg/ml; P less than 0.05). There were no differences in the number of follicles aspirated or oocytes retrieved. In 19 patients with unilateral structures, the ipsilateral ovary produced fewer follicles (2.5 +/- 0.5 versus 3.9 +/- 0.6; P less than 0.05); however, there were no differences in the number or maturity of oocytes recovered. Since the numbers of oocytes recovered were equivalent in the presence or absence of ovarian cystic structures, their presence is not an indication to cancel an IVF cycle.

Adult↗
PubMed1990

Immunoreactive epidermal growth factor concentrations in follicular fluid obtained from in vitro fertilization.

Immunoreactive epidermal growth factor (EGF) was measured in follicular fluid (FF) obtained at the time of oocyte retrieval for in vitro fertilization from cycles with (91 follicles) and without (128 follicles) the gonadotropin-releasing hormone agonist leuprolide acetate (LA). Follicular fluid immunoreactive EGF levels in the non-LA cycles correlated with androstenedione but not estradiol or progesterone levels from follicles with prophase I oocytes or from all follicles taken together, but not from metaphase I or metaphase II oocyte containing follicles alone. In non-LA cycles, FF immunoreactive EGF levels were lower in follicles that contained metaphase I or II oocytes than prophase I oocytes. Additionally, FF immunoreactive EGF levels were lower in follicles containing metaphase I or II oocytes from non-LA than LA cycles. We conclude that immunoreactive EGF is present in FF. Leuprolide acetate may affect FF immunoreactive EGF levels.

Androstenedione↗
PubMed1990

The relationship between serum estradiol-17 beta concentrations and induced pituitary luteinizing hormone surges in postmenopausal women.

The present study was designed to evaluate the effect of different serum concentrations of estradiol-17 beta (E2) on pituitary luteinizing hormone (LH) release in postmenopausal women. Serum E2 levels were evaluated in healthy postmenopausal women while they wore two, four, and six transdermal E2 delivery systems. The mean serum E2 levels at 48 hours after application of the devices were 185.5, 338.9, and 520.5 pg/mL, respectively, which were significantly different from each other. Serum E2 levels were stable throughout the first 48 hours of patch application but declined by a mean of 54% between 48 and 72 hours. Pituitary LH surges were induced with all three serum concentrations of E2 but were present more often with the higher serum values. There were no significant differences between the mean interval of device utilization and initiation, height, or duration of the induced pituitary LH surge at any of the three serum E2 concentrations studied.

Adult↗
PubMed1989

Correlation of follicular diameter with oocyte recovery and maturity at the time of transvaginal follicular aspiration.

Forty-four consecutive patients undergoing transvaginal follicular aspiration for in vitro fertilization underwent ultrasonic measurement of follicular diameter at the time of oocyte retrieval to determine the correlation of follicular size with recovery rates and oocyte maturity. Based on the results of 412 follicles aspirated, the data were grouped by size (less than or equal to 11, 12-14, 15-17, 18-20, and greater than or equal to 21 mm) and oocyte maturity. Recovery rates were significantly higher in 18- to 20-mm follicles (P less than 0.01) and lower in those less than or equal to 11 mm (P less than 0.001). The probability of retrieving a metaphase I or II oocyte was significantly lower in follicles less than or equal to 11 mm (P less than 0.001), somewhat higher in 12- to 14-mm follicles (P less than 0.01), and equally high among the other groups. There were no differences in the incidence of fractured zonas. We conclude that follicles greater than or equal to 15 mm provide the highest probability of retrieving mature oocytes and the low recovery rates of mature oocytes from follicles less than or equal to 11 mm suggest that, in selected circumstances, the operating surgeon may choose not to aspirate them.

Cell Cycle↗
PubMed1989

A prospective randomized comparison of single- and double-lumen needles for transvaginal follicular aspiration.

Patients undergoing ultrasound-directed transvaginal follicular aspiration in a large in vitro fertilization (IVF) program were randomized for retrieval with either a single-lumen needle (SLN; N = 22) or a double-lumen needle (DLN; N = 22) to compare recovery rates and the technical aspects of their use. Two hundred ten and two hundred two follicles were aspirated with each needle, respectively. Follicular diameters were measured ultrasonically at the time of aspiration and recorded. One or more washes were performed when using the DLN and the SLN was withdrawn each time to recover the fluid in the dead space of the needle. The distribution of follicular sizes was the same for both needles. Oocyte recovery rates (SLN = 65.7%; DLN = 63.9%) and the incidence of fractured zonae (SLN = 9.1%; DLN = 6.4%) were the same for both needles (alpha greater than 0.50; beta less than 0.01). Although there were no differences between the two needles in the number of oocytes provided for IVF, there were technical differences. The DLN needle was more flexible and frequently deviated from the projected path as observed by ultrasound. The SLN may be preferable because it is technically easier to use; however, there may remain specific indications for the use of the DLN.

Evaluation Studies as Topic↗
PubMed1989

Effects of clomiphene citrate on episodic luteinizing hormone secretion throughout the menstrual cycle.

Pituitary luteinizing hormone secretory dynamics (pulse frequency and amplitude) were evaluated in eight normal women administered clomiphene citrate or placebo. After 5 days of treatment clomiphene citrate was found to increase mean luteinizing hormone secretion by increasing the amount of pituitary luteinizing hormone released per pulse. No change in pituitary luteinizing hormone interpulse interval was found in the follicular phase of the cycle, although a faster pulse frequency in the luteal phase was found after clomiphene citrate when compared with placebo. No differences were found in the luteal phase (pulse frequency, amplitude, and mean luteinizing hormone level) after clomiphene citrate versus placebo in the volunteers. These data suggest that the principal mechanism of action of clomiphene citrate is an increase in the concentration of hypothalamic gonadotropin releasing hormone into the hypothalamic-pituitary portal circulation, with a resultant increase in pituitary luteinizing hormone secretion.

Adult↗
PubMed1989

Follicle-stimulating hormone levels on cycle day 3 are predictive of in vitro fertilization outcome.

Cycle day 3 basal levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), and estradiol (E2) were measured in 441 patients in 758 consecutive cycles to determine their predictive value for stimulation quality and pregnancy rates in vitro fertilization (IVF). Patients with low basal FSH levels (less than 15 mIU/ml) had higher pregnancy rates per attempt than those with moderate levels (15 to 24.9 mIU/ml), both of which were higher than those with high FSH levels (greater than 25 mIU/ml). Basal LH and E2 values did not improve the predictive value beyond that provided by FSH. Ongoing pregnancy rates per attempt in the low, moderate, and high FSH groups were 17.0%, 9.3%, and 3.6%, respectively (P less than 0.01). The three groups differed significantly in the percentage of patients having two ovaries, the mean number of follicles aspirated per retrieval, the mean number of preovulatory oocytes obtained, and peak E2 values (P less than 0.01). Cycle day 3 FSH levels are predictive of pregnancy outcome and stimulation characteristics in IVF, and may be useful in counseling patients.

Estradiol↗