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Biomedical subjects

K J Ryan

Publications and source records attributed to K J Ryan.

At least 73 records · Page 4Linked to original sources
PubMed1984

Episodic secretory patterns of immunoreactive luteinizing hormone-releasing hormone (IR-LH-RH) in the systemic circulation of normal women throughout the menstrual cycle.

Using established radioimmunoassays for measuring plasma luteinizing hormone-releasing hormone (LH-RH) and serum gonadotropins, we studied the secretory dynamics of these hormones in eight normal ovulatory women during different phases of their menstrual cycle. All of the women demonstrated evidence of pulsatile immunoreactive LH-RH (IR-LH-RH) release throughout the cycle, with IR-LH-RH concentrations fluctuating between 0.5 and 35 pg/ml in the systemic circulation. Analysis of IR-LH-RH episodic secretions revealed a significant increase of both mean IR-LH-RH concentrations (P less than 0.001) and pulse frequency (P less than 0.05) during the periovulatory period. Furthermore, plasma IR-LH-RH titers in five normal women studied during the morning and night at mid-menstrual cycle fluctuated markedly, with slightly greater episodic discharges observed during the night than in the morning (P less than 0.05) and no significant change in pulse frequency.

Adult↗
PubMed1984

Vasomotor flushes and the release of peripheral immunoreactive luteinizing hormone-releasing hormone in postmenopausal women.

The plasma concentrations of immunoreactive luteinizing hormone-releasing hormone (IR-LH-RH) and LH and the peripheral skin temperature of symptomatic menopausal women were recorded continuously and compared with those of asymptomatic menopausal women. These studies were performed by an intermittent withdrawal technique (n = 13) and a continuous withdrawal technique (n = 3). The mean plasma concentration of IR-LH-RH was much higher in symptomatic than in asymptomatic women by both methods of analysis. Large episodic secretory spikes of IR-LH-RH and a temporal correlation between the IR-LH-RH spikes and temperature elevations was found (P less than or equal to 0.025) only in symptomatic women.

Adult↗
PubMed1984

Insulin stimulates androgen accumulation in incubations of human ovarian stroma and theca.

The effects of insulin on ovarian steroidogenesis were examined in four-day incubations of minced stroma and theca obtained from a woman with hyperandrogenism, insulin resistance, and acanthosis nigricans, and from a normally cycling woman. In incubations of theca obtained from the patient with hyperandrogenism, insulin resistance, and acanthosis nigricans, lutenizing hormone (LH) (25 ng/mL) alone stimulated androstenedione, testosterone, progesterone, and estradiol accumulation. Insulin (500 ng/mL) alone stimulated androstenedione and testosterone accumulation, but not progesterone or estradiol accumulation. In incubations of stroma obtained from the hyperandrogenism, insulin resistance, and acanthosis nigricans patient, LH (25 ng/mL) alone stimulated androstenedione and testosterone accumulation, but not dihydrotestosterone accumulation. Insulin (500 ng/mL) alone stimulated androstenedione, testosterone, and dihydrotestosterone accumulation. In incubations of stroma from the normally cycling woman, LH plus insulin acted synergistically to stimulate androstenedione accumulation. These results suggest that insulin may be a regulator of steroid biosynthesis in the thecal and stromal compartments of the human ovary.

Acanthosis Nigricans↗
PubMed1984

Work and pregnancy.

Pregnancy outcomes of 7,155 women who worked between one and nine months of pregnancy were compared with outcomes of 4,018 women who were not employed. There were no differences in rates of prematurity, Apgar score, birthweight, perinatal death rate, or malformation prevalence. Working women were divided into those who left employment during the first eight months and those who worked all nine months. The latter had a lower rate of adverse outcome than the other working group and the nonworking group. This indicates that working to term in the absence of contraindications does not impose an added risk on mother or infant. After control of confounding by parity and other relevant factors, an increased risk of prolonged gestational age was seen among primiparous working women. There was an increased risk of fetal distress among those women leaving work prior to nine months who were having their third or subsequent child. A small decrease in birth weight was seen among women who left work prior to term but not among those who worked all nine months. Overall the results are reassuring that working during pregnancy is not in itself a risk factor for adverse outcome.

Adolescent↗
PubMed1984

The computer in microbiology: future applications in test performance and reporting.

The use of minicomputers dedicated to laboratory use offers the greatest hope for continued progress in computerization of clinical microbiology. Such systems can be interfaced with microcomputers performing discrete tasks within the laboratory and with larger computers to form a total hospital or interhospital information system. As such systems are designed they should include features that allow ready access to the microbiologic data without reentry of primary results or delays of days to weeks. Many of these features have been accomplished in existing laboratory systems.

Computers↗
PubMed1984

The nonluteal porcine ovary as a source of angiogenic activity.

Nonluteal ovarian tissue extracts were tested for their ability to stimulate migration and proliferation of cultured bovine capillary endothelial cells. Stimulation of migratory and proliferative activity was found in the 105,000 X g supernatant of homogenates of either whole nonluteal porcine ovaries or isolated theca (follicular walls). Maximal proliferative and migratory activity was obtained with 1-10 micrograms homogenate protein. Neither follicular fluid nor extracts of granulosa cells showed significant activity when tested over a broad concentration range. The proliferative and migratory activities were associated with a heat-labile, nondialyzable, protease-sensitive fraction that was soluble in 40%, but not 60% (NH4)2SO4. The tissue extracts that effectively stimulated growth and migration of capillary endothelial cells in vitro also stimulated the formation of new capillary blood vessels in an angiogenesis assay performed on chick chorioallantoic membranes.

Allantois↗
PubMed1984

Fertility after induced abortion: a prospective follow-up study.

Abortion has been alleged to cause sterility. To address this issue, 1235 postabortal women, 912 women recently delivered, and 939 women from the authors' gynecology clinics were studied for as long as 3.5 years. Cumulative pregnancy rates were similar for abortion group patients, delivery group patients, and the previously pregnant clinic group. When pregnancy rates were examined by different assumptions as to entrance into follow-up, the abortion group differed only in a somewhat lower pregnancy rate after nine months, when the use of contraceptives was greater than that of the other two groups. Pregnancy rates for all three groups were influenced by age of subject, parity, race, marital and Medicaid status, and a history of urinary tract infections. Induced abortion status did not influence pregnancy rates except that women reporting three or more induced abortions had a higher pregnancy rate.

Abortion, Induced↗
PubMed1983

Lack of association between contraceptive usage and congenital malformations in offspring.

Previous reports have linked the use of oral contraceptives and spermicides to the occurrence of malformations in offspring. With information from 12,440 women interviewed during the delivery hospitalization, we found no relationship between contraceptive method and the occurrence of malformations. Whereas any unnecessary drug should be avoided during pregnancy, prior contraceptive method seems to be unrelated to the risk of congenital malformations.

Abortion, Induced↗
PubMed1983

Hyperandrogenism, insulin resistance, and acanthosis nigricans syndrome: a common endocrinopathy with distinct pathophysiologic features.

The HAIR-AN syndrome that consists of hyperandrogenism (HA), insulin resistance (IR), and acanthosis nigricans (AN) is an underdiagnosed endocrinopathy, because hyperandrogenic women are not commonly screened for insulin resistance or acanthosis nigricans. The distinct pathophysiologic features of the HAIR-AN syndrome are discussed in detail. In this syndrome, the primary pathophysiologic derangements are the insulin resistance and the hyperandrogenism. The acanthosis nigricans is an epiphenomenon of these primary processes. In patients with the HAIR-AN syndrome, the degree of severity of the insulin resistance is positively correlated with the degree of severity of the hyperandrogenism. In patients with adequate pancreatic beta-islet cell reserve, insulin resistance results in a long-term increase in circulating insulin levels. The hyperinsulinemia probably directly stimulates ovarian androgen production. In turn, hyperandrogenism itself produces insulin resistance. This positive feedback loop between insulin resistance and hyperandrogenism propagates the disease, and increases its severity over time. The relationship between insulin resistance and hyperandrogenism may explain the hyperandrogenemia seen in the following disease processes: obesity, acromegaly, lipoatrophic diabetes, leprechaunism, and Kahn types A and B insulin resistance.

Acanthosis Nigricans↗
PubMed1983

The relationship between induced abortion and outcome of subsequent pregnancies.

We analyzed interview and record review data from 9,823 deliveries to evaluate the relationship between prior history of induced abortion and subsequent late pregnancy outcomes. Complications such as bleeding in the first and third trimesters, abnormal presentations and premature rupture of the membranes, abruptio placentae, fetal distress, low birth weight, short gestation, and major malformations occurred more often among women with a history of two or more induced abortions. A logistic regression analysis to control for multiple confounding factors showed that a history of one induced abortion was statistically significantly associated with first-trimester bleeding but with no other untoward pregnancy events, and a history of two or more induced abortions was statistically associated with first-trimester bleeding, abnormal presentations, and premature rupture of the membranes. While these relationships merit further research, the results of this study are largely reassuring. A history of one or more prior induced abortions does not appear to increase substantially the risk of adverse late outcomes of subsequent pregnancies.

Abortion, Induced↗
PubMed1983

Significance of the delta 5 and delta 4 steroidogenic pathways in the hamster preovulatory follicle.

Isolated hamster granulosa cells and theca from preovulatory follicles were incubated in vitro for 2 and 6 h in the absence/or presence of LH and steroid substrates. The purpose of the experiments was to determine, in theca, the relative activities of the delta 5 and delta 4 pathways under controlled conditions, and to compare the ability of granulosa cells and theca to form progesterone from exogenous pregnenolone. The results of the experiments show that the delta 5 pathway in theca predominates before and up to 2 h after LH stimulation. The delayed effect of LH after 2 h is a switch from delta 5 to delta 4 as the major metabolic pathway. Progesterone formation from exogenous pregnenolone is 7 to 10 times greater in unstimulated granulosa cells than in theca. Acute effects of LH lead to increased conversion of exogenous pregnenolone to progesterone in granulosa cells but not theca. LH does, however, acutely stimulate the thecal conversion of DHEA to androstenedione. The longer term effect of LH in both cell types is to increase pregnenolone conversion to progesterone.

Androstenedione↗
PubMed1983

Demonstration of bacteroides capsules by light microscopy and ultrastructural cytochemistry.

Forty-six anaerobic gram-negative bacilli, including 26 members of the Bacteroides fragilis group (BFG), were examined for capsules by the India ink technic. Thirty-five were encapsulated, including all the BFG strains. As a follow-up, seven of these isolates and two previously studied reference strains (B. fragilis ATCC 23745 and Bacteroides vulgatus ATCC 8482) were examined for capsules by ultrastructural cytochemistry. Using the periodic acid thiocarbohydrazide silver proteinate (PATCSP) method of Thiéry, all the BFG examined were encapsulated. In addition to the reference strains, this included one strain of B. fragilis and four of Bacteroides thetaiotaomicron. One non-BFG strain showed no capsular material. Differences between these results and those reported previously with the ruthenium red technic may reflect species differences in the chemical composition of Bacteroides capsules.

Bacteroides fragilis↗
PubMed1983

An endogenous ovarian growth factor which stimulates BALB/3T3 and granulosa cell proliferation.

Extracts of whole porcine ovary stimulate BALB/3T3 [3H] DNA synthesis in BALB/3T3 cells. Biochemical characterization indicates the growth factor is associated with a soluble cationic protein that is labile to heat, stable to dithiothreitol treatment and elutes from Sephadex G-100 between chymotrypsin (25,000 Mr) and cytochrome C (12,700 Mr). Extracts of thecal tissue have growth-promoting activity in both granulosa and 3T3 cells. Conditioned medium from thecal but not granulosa cell cultures stimulates [3H] DNA synthesis in quiescent 3T3 and granulosa cells. The results indicate the presence of an endogenous protein ovarian growth factor found in the theca that stimulates granulosa cell proliferation in vitro.

Animals↗
PubMed1983

Neisseria lactamica septicemia in an immunocompromised patient.

Neisseria lactamica was isolated from the blood of a 7-year-old girl who was immunosuppressed from chemotherapy for acute lymphocytic leukemia. She was receiving trimethoprim-sulfamethoxazole prophylactically. The isolate was resistant to trimethoprim-sulfamethoxazole and sensitive to penicillin. The patient responded to intravenous penicillin therapy. The organism did not produce immunoglobulin A1 protease.

Child↗
PubMed1983

Aromatization of norethindrone to ethinyl estradiol by human placental microsomes.

The interaction of 19-norethindrone [4-estren-17 alpha-ethinyl-17 beta-ol,3-one (NET)] with human placental microsomes was investigated using enzymatic and spectral techniques. The incubation of [6,7-3H]norethindrone with human placental microsomes, NADPH, and molecular oxygen resulted in the production of ethinyl estradiol [1,3,5-(10)estratrien-17 alpha-ethinyl-3,17 beta-diol (EE)]. The reaction was linear with respect to time and protein concentration. Androstenedione inhibited the enzymatic aromatization of NET to EE. The product was identified by thin layer chromatography, recrystallization to constant specific activity, and derivative formation. No acid or base was used in any step of product identification. To ensure that spontaneous aromatization of metabolites of NET did not contribute to our results, representative samples were treated with sodium borohydride before processing. Sodium borohydride reduces the 4-en-3-one grouping of the A-ring, thereby preventing chemical aromatization. Sodium borohydride treatment did not reduce our observed yields of EE from NET. The addition of NET to a preparation of solubilized, partially purified placental microsomal cytochrome P-450 yielded a type I cytochrome P-450 binding spectrum. The apparent spectral dissociation constant for NET binding to cytochrome P-450 was 28 microM. These results suggest that NET is enzymatically aromatized to EE by human placental microsomes.

Borohydrides↗
PubMed1983

The association of marijuana use with outcome of pregnancy.

We analyzed interview and medical record data of 12,424 women to evaluate the relationship between marijuana usage and adverse outcomes of pregnancy. Low birthweight, short gestation, and major malformations occurred more often among offspring of marijuana users. When we used logistic regression to control for demographic characteristics, habits, and medical history data, these relationships were not statistically significant. The odds ratio for the occurrence of major malformations among marijuana users was 1.36, higher than odds ratios for other exogenous variables, and the 95 per cent confidence interval was 0.97-1.91. More data are needed to establish firmly or rule out an association between marijuana usage and major malformations. Until more information is available, women should be advised not to use marijuana during pregnancy.

Abnormalities, Drug-Induced↗
PubMed1983

The association of alcohol consumption with outcome of pregnancy.

Patterns of alcohol consumption were assessed in 12,440 pregnant women interviewed at the time of delivery. Only 92 women (0.7 per cent) reported drinking 14 or more drinks per week, with most consuming fewer than 21 drinks per week. In the crude data, alcohol intake of 14 or more drinks per week was associated with a variety of adverse pregnancy outcomes, including low birthweight, gestational age under 37 weeks, stillbirth, and placenta abruptio. After use of logistic regression to control for confounding by demographic characteristics, smoking, parity and obstetric history, only the association of placenta abruptio with alcohol consumption of 14 or more drinks per week remained statistically significant. With the exception of placenta abruptio, alcohol intake of fewer than 14 drinks per week was not associated with and increased risk of any adverse outcome. No association was seen with congenital malformations at any level of alcohol intake.

Adult↗