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Biomedical subjects

A Templeton

Publications and source records attributed to A Templeton.

At least 145 records · Page 8Linked to original sources
PubMed1990

Interaction of angiotensin II and atrial natriuretic peptide in the human fetoplacental unit.

We have identified two classes of membrane receptor for atrial natriuretic peptide (KD (dissociation constant) 0.2, 70.1 nmol/L) and angiotensin II (KD 1.7 nmol/L, 15.2 nmol/L) in human fetoplacental vasculature. In addition, in the isolated perfused placenta atrial natriuretic peptide inhibited the vasoconstrictor action of angiotensin II. These findings suggest that atrial natriuretic factor may regulate fetoplacental blood flow.

Angiotensin II↗
PubMed1990

Pathophysiology of mild endometriosis: review of literature.

Endometriosis is a puzzling condition and the literature is characterized by a large number of uncontrolled reports on its aetiology and pathophysiology. In particular the relationship between mild endometriosis and subfecundity is uncertain. This paper critically reviews the published literature on the pathogenesis, prevalence, menstrual symptomatology and natural history of endometriosis. Furthermore, factors implicated in causing subfecundity in relation to endometriosis and the impact of various treatments in enhancing fertility among women with mild endometriosis have been assessed.

Ascitic Fluid↗
PubMed1990

The impact of treatment on the natural history of endometriosis.

A group of 50 infertile female patients was assessed laparoscopically to study the natural history of endometriosis. They were treated either with danazol (n = 21), or diathermy ablation (n = 13) or had conservative surgery with postoperative danazol (n = 5) or were left untreated (n = 11). All these patients had second look laparoscopy performed after a mean interval of 12 months (range 9-18 months). Improvement was noted among 53% of those treated with danazol, 70% treated with diathermy, 80% treated with surgery and danazol and 27% of those left untreated. The status of endometriosis remained unchanged among 14% of those treated with danazol, 8% treated by diathermy and 9% of those left untreated. However, the disease became worse in the remaining women, 33% in the danazol treated group, 22% treated by diathermy, 20% treated with surgery and danazol and 64% of those left untreated. Thus treatment hinders progression in a majority of patients, and conversely, there is a small but definite spontaneous regression rate.

Adult↗
PubMed1990

In-vivo bioactivity of gonadotrophin surge attenuating factor (GnSAF).

Gonadotrophin surge attenuating factor (GnSAF) is a nonsteroidal ovarian factor responsible for the attenuation of the endogenous LH surge in superovulated cycles. To study the bioactivity of GnSAF in vivo, the pituitary response to exogenous GnRH was investigated in 13 normally ovulating women during spontaneous and FSH-treated cycles. GnRH experiments were performed at three stages of both spontaneous and FSH cycles, i.e. early (n = 8), mid- (n = 8) and late follicular phase (n = 8). LH response to GnRH increased significantly from the early to late follicular phase in the spontaneous cycles, while in the FSH cycles it decreased significantly in mid- and increased in late follicular phase. A marked attenuation of the LH response to GnRH during both the mid- and late follicular phase was seen in the FSH as compared to the corresponding spontaneous cycles. We conclude that in superovulated cycles small, growing follicles produce GnSAF.

Biological Factors↗
PubMed1990

Superovulation induction in women suppresses luteinizing hormone secretion at the pituitary level.

In superovulated women the pituitary response to GnRH is markedly attenuated by an unspecified ovarian factor(s). To examine the site of attenuation, the response of the pituitary to GnRH was investigated in five normally ovulating women during the late follicular phase of 3 cycles, i.e. a spontaneous (control) cycle, a cycle treated with 'pure' FSH, and a cycle treated with a combination of 'pure' FSH and pulsatile GnRH, via a pump (15 micrograms/pulse). The oestradiol levels (mean +/- SEM) at the time of the GnRH challenge were respectively 646 +/- 35, 1692 +/- 282 and 5976 +/- 1129 pmol/l. The size of the leading follicle was similar in all groups. Serum LH levels during treatment with FSH decreased significantly, while during treatment with FSH plus GnRH they increased initially and then decreased progressively. The response of pituitary LH to GnRH was significantly attenuated during treatment with FSH and FSH plus GnRH, as compared to the spontaneous cycles, but was not abolished. The attenuation was significantly greater in the FSH plus GnRH cycles (94%) than in the FSH cycles (59%). We conclude that in superovulated cycles, the attenuation of the pituitary response to GnRH increases with the degree of ovarian hyperstimulation. It is suggested that the responsible unspecified ovarian factor(s) exerts its effects at least at the pituitary level.

Female↗
PubMed1989

Levels of the antiprogestin RU 486 and its metabolites in human blood and follicular fluid following oral administration of a single dose.

Using high-pressure liquid chromatography (HPLC) the antiprogestin RU 486 and two of its metabolites (N-monodemethyl RU 486 and propargyl RU 486) were measured in plasma and follicular fluid of 21 women requesting laparoscopic sterilization. Pretreatment of the women involved ovulation induction with clomiphene and HCG. RU 486 (100 mg) was administered orally and 1 h later blood samples were withdrawn. Thirty-four hours later, at laparoscopy, samples of both blood and follicular fluid were collected. During the 34-h period the average plasma level of RU 486 decreased from 1.93 mumol/l to 0.91 mumol/l, i.e. by -50%. The latter concentration of RU 486 was not significantly different from that found in follicular fluid (0.79 mumol/l). The monodemethyl metabolite exhibited significantly higher plasma levels (3.09 mumol/l) than RU 486 1 h after administration. Thirty-four hours later these levels had decreased to 0.92 mumol/l, i.e. by 70%. In follicular fluid, the levels of the monodemethyl metabolite (1.76 mumol/l) were significantly higher than those of RU 486 (0.79 mumol/l). Because of background noise, only approximate values were established for the propargyl metabolite. These were 0.67 and 0.40 mumol/l, respectively, in plasma and 0.42 mumol/l in follicular fluid. The results indicate that RU 486 and two of its major metabolites can readily cross the blood-follicle barrier of human pre-ovulatory follicles.

Abortifacient Agents↗
PubMed1989

The relationship between endometriosis and semen analysis: a review of 490 consecutive laparoscopies.

Laparoscopy was carried out on 490 infertile women whose partners had semen analyses showing a minimum of 5 X 10(6) motile spermatozoa/ml. Patients were divided into two groups using WHO criteria: those in whom the semen parameters were normal and those in whom there was any abnormality. The overall incidence of endometriosis was the same in both groups. Among women with primary infertility, mild endometriosis was significantly more common in the abnormal semen group. Thus among couples in whom there is an explanation for continuing sub-fertility, mild endometriosis is more common. This finding calls into question the causal relationship between endometriosis and primary infertility and suggests that in susceptible women, infertility may predispose towards the occurrence of endometriosis.

Adult↗
PubMed1989

Characterization of the pseudocapsule of soft-tissue sarcomas. An experimental study in rats.

The effect of preoperative radiation therapy on the pseudocapsule of experimental rat soft-tissue sarcomas has not been histologically evaluated in a controlled study. The irradiated animal showed marked thickening of the capsular structure surrounding the sarcoma. Everywhere morphologically distinct from the tumor, there was no evidence of tumor invasion into or through this capsular structure. The membrane was consistently thicker and more hyalinized than in the control animals. The nonirradiated animals showed a minimal pseudocapsular structure with a characteristic tumor penetration. Irradiation produced distinct histologic changes in the pseudocapsule. Although assumed on the basis of clinical observations alone, irradiation-induced pseudocapsule has not previously been demonstrated in an experimental model of soft-tissue sarcoma.

Animals↗
PubMed1989

Timing of ovulation for artificial insemination.

Two studies involving eighty women having treatment with artificial insemination by donor (AID) have demonstrated that the use of a urinary semi-quantitative assay for luteinising hormone (LH) gives pregnancy rates comparable to those obtained using plasma LH for the timing of insemination. The advantage of self test assay is evident in a scattered region such as Grampian.

Adult↗
PubMed1988

Changes in serum prolactin levels during the follicular phase and the endogenous luteinizing hormone surge of cycles hyperstimulated with follicle stimulating hormone.

The pattern of serum PRL levels during superovulation induction with pulsatile 'pure' FSH was investigated in 10 normally ovulating women. They were studied in two consecutive cycles, i.e. an untreated spontaneous and an FSH stimulated cycle. An endogenous LH surge occurred in all 10 spontaneous cycles and in five of the FSH cycles. Midcycle PRL levels were significantly higher in the FSH stimulated than in the spontaneous cycles (P less than 0.01). In both groups of cycles, circadian periodicity of serum PRL levels during the LH surge was different from that during the late follicular phase with higher levels at midnight, although in the FSH cycles PRL secretion showed a sustained increase over 24 h. A nadir of PRL levels was found between 0900 h and 1200 h. In contrast, progesterone secretion during the LH surge showed a nocturnal increase with the highest value between 0600 h and 1200 h and the lowest at midnight. In the FSH cycles without an LH surge, PRL levels increased as long as FSH administration was continued and showed a significant positive correlation with the increasing serum oestradiol levels (r = 0.77). We conclude that ovarian hyperstimulation is a potent stimulus of PRL secretion in women. It is suggested that the midcycle endogenous LH surge facilitates the evening PRL secretion, while induction of multiple folliculogenesis amplifies the 24 h pattern of PRL secretion.

Circadian Rhythm↗
PubMed1988

Blockage of the positive feedback effect of oestradiol during prolonged administration of clomiphene citrate to normal women.

The effect of clomiphene citrate on the occurrence and timing of the endogenous LH surge in superovulated cycles is unclear. To study further this event, five normally ovulating women were treated with clomiphene citrate 100 mg per day in two different cycles, that is, for 5 days in one cycle (days 2 to 6, CC-5) and for 15 days in another cycle (days 2 to 16, CC-15). During the CC-5 cycle, the normal pattern of LH levels seen in spontaneous cycles was observed with an endogenous LH surge in all women followed by ovulation and normal luteal function. In contrast, during the CC-15 cycle, a continuous and progressive increase of basal LH levels was seen with no surge, resulting in follicular luteinization but no ovulation. The results suggest that in normal women treated with clomiphene the occurrence of an endogenous LH surge is dependent on a significant decrease in the circulatory concentration of clomiphene at mid-cycle.

Clomiphene↗
PubMed1988

The effect of the antiprogestin mifepristone (RU 486) on maturation and in-vitro fertilization of human oocytes.

The effect of RU 486 (mifepristone), a potent antiprogestin, on the in-vitro fertilization of human oocytes was investigated. In 40 normal volunteer women requesting laparoscopic sterilization, follicle aspiration for oocyte recovery was attempted 34 h after the injection of 5000 i.u. human chorionic gonadotrophin (hCG). Twenty women were allocated to receive 100 mg RU 486 orally 1 h before the hCG injection, the remaining 20 women acted as controls. There was no significant difference in the cleavage rate of the oocytes after fertilization in vitro between the two groups (56% and 66% respectively). Also, the morphological characteristics of the cleaving oocytes and the concentrations of oestradiol, progesterone and androstenedione in the follicular fluid of the leading follicle did not differ significantly between the two groups. Since RU 486 was detected in substantial amounts in the follicular fluid specimens, these results suggest that progesterone is not critical for the final stages of human oocyte maturation.

Estrenes↗
PubMed1988

Prediction of ovulation using a dipstick sensitive to urinary luteinising hormone.

Accurate prediction of ovulation is essential for patients receiving donor insemination (AID). In 9 patients, detection of the urinary luteinising hormone (LH) surge by monoclonal antibody immunospecific dipstick tests (Ovustick) for both home and laboratory use was assessed with simultaneous quantitative estimations of plasma and urinary LH. In all patients the Ovustick accurately detected within 24 hours the beginning of the plasma LH surge. This test may prove to be a useful method for ovulation prediction but further evaluation is required.

Adult↗
PubMed1987

Temporal and spatial heterogeneity of mtDNA polymorphisms in natural populations of Drosophila mercatorum.

Restriction endonuclease analysis of mtDNA was used to examine the genetic relatedness of several geographically separated isolines of the Drosophila mercatorum subgroup. In addition, we examined the temporal and spatial distribution of two mtDNA restriction site polymorphisms produced by the enzymes BstEII and BstNI at a single locality--Kamuela, Hawaii. Due to small sample sizes of some collections and the undesirable dependance of the estimation of polymorphism frequency on its variance, an arcsin square root transformation of the frequency data was used. We also use an Fst estimator of our transformed frequencies to demonstrate considerable spatial and temporal differentiation within the Kamuela population. In contrast, isozyme data from the same population reveals no pattern of differentiation. The temporal and geographic heterogeneity and population subdivision detected with mtDNA analysis also is consistent with the known dispersal behavior and ecological constraints of this species. The mtDNA data in conjunction with the isozyme data show that the population structure of the Kamuela D. mercatorum is close to the boundary line separating panmixia from subdivision, a conclusion that could not be made from isozyme data alone.

Alleles↗
PubMed1987

Effect of high dose exogenous oestrogen on midcycle luteinizing hormone surge in human spontaneous cycles.

Induction of multiple follicular development in women results in supraphysiological serum oestradiol (E2) levels and marked reduction of the endogenous LH surge. To examine whether high serum E2 levels at midcycle can suppress gonadotrophin secretion during the LH surge, five normally ovulating women were given an intramuscular injection of 10 mg oestradiol benzoate 6-42 h before the expected endogenous LH surge. The results were compared with the preceding untreated control cycle. Serum E2 levels at the onset of the LH surge (mean +/- SEM) were significantly higher in the oestrogen-treated cycles (13,600 +/- 1963 pmol/l) than in the control cycles (1012 +/- 116 pmol/l) (P less than 0.001). The duration of the LH surge (64.8 +/- 2.2 h) and LH peak levels (136 +/- 9.6 mIU/ml) in the oestrogen treated cycles were similar to those in the control cycles (61.2 +/- 3.9 and 119 +/- 9.4 mIU/ml respectively) (mean +/- SEM). The cycle day on which the LH surge started and the size of the dominant follicle, as assessed by ultrasound, did not differ significantly between the two groups of cycles. These results show that in spontaneous cycles the endogenous LH surge is neither reduced nor amplified by the induction of supraphysiological serum E2 levels during the immediate pre-ovulatory stage.

Estradiol↗