PubMed Health⌕ Search

Biomedical subjects

C Kirby

Publications and source records attributed to C Kirby.

47 records · Page 3Linked to original sources
PubMed1983

Incidence of the luteinized unruptured follicle phenomenon in cycling women.

A prospective study is presented in order to determine the frequency of the luteinized unruptured follicle (LUF) in a population of 66 regularly cycling women. They were monitored by daily ultrasound for a total of 183 cycles, and the LUF was detected in 9 cycles, giving an incidence of 4.9%. The results of daily changes of luteinizing hormone, estradiol, and progesterone provide support for the thesis that the LUF behaves steroidogenically as a corpus luteum and that the luteal phase duration is normal. Continued monitoring in 35 cycles revealed a recurrence in only one case during a fourth subsequent cycle. Thus, the findings indicate that the LUF is a sporadic and infrequent phenomenon. It is therefore an uncommon cause of infertile cycles in potentially fertile women and represents a biologic variable rather than a syndrome. Based on ultrasonic and endocrine observations, a mechanism is proposed for the resolution of the LUF.

Adult↗
PubMed1983

Elimination of Sendai (parainfluenza type 1) virus infection from mice by embryo transfer.

Preimplantation embryos collected from mice in the acute phase of Sendai virus infection were not infected. Transfer of embryos from infected donors did not transmit the virus to the recipient foster mothers or to their progeny. The pregnancies were normal with no differences in implantation rate or number of live births when compared with control transfers of embryos collected from non-infected donors.

Animals↗
PubMed1983

The effect of clomid induced superovulation on human follicular and luteal function for extracorporeal fertilization and embryo transfer.

The administration of clomiphene citrate (Clomid) 150 mg/day from days 5-9 of the menstrual cycle to spontaneously ovulatory women in order to induce adequate multiple follicular development followed by timed laparoscopic aspiration of mature oocytes does not appear to impair luteal phase length or the steroid pattern of oestradiol-17 beta (E2) or progesterone (P) production as reflected by their peripheral blood concentrations. In Clomid stimulated cycles where preovular oocyte pickup (OPU) and embryo transfer (ET) occurred but no recognizable pregnancy resulted, the cycle length was 30.0 (s.e.m. = 0.3) days, the follicular phase length was 15.6 (s.e.m. = 0.3) days and the luteal phase length was 14.4 (s.e.m. = 0.3) days, which did not differ from a group of women having spontaneous ovular cycles. Following Clomid stimulation the dominant follicle was similar in size to the pre-ovulatory follicle in spontaneous uniovular cycles, but the second, third, fourth and fifth order follicles were significantly larger (P less than 0.0001). The ultimate test of luteal competence was the successful implantation of 11 concepti in 7 women (4 sets of twins) from 49 laparoscopies (14%) or 33 embryo transfers (21%). Comparisons between conceptual and non-conceptual embryo transfers following identical Clomid regimes showed no difference between plasma E2 concentrations at the time of hCG administration or the start of an endogenous LH rise; follicle volume, follicular fluid E2, P and testosterone concentrations were also not different. However, there was a trend for follicular P to be higher in the non-conceptual group indicating that advanced luteinization may hinder successful implantation. The follicular fluid androstenedione (A4) concentration was significantly lower in the conceptual group and the total androgen concentration (A4 + T) was also lower which was indicative of active aromatase activity in these follicles. It was concluded from this study that there was no indication to give exogenous hormonal support to the luteal phase, provided there was both optimal follicular growth and steroidogenic function following Clomid stimulation and that exogenous hCG was administered very close to the expected rise of LH. This observation was supported by the finding that timing of OPU based on a knowledge of the start of the LH surge was associated with a higher pregnancy rate than when hCG was administered and indicates that the endogenous mid-cycle events may permit superior maturation of the oocyte and/or permit better synchronization of endometrial maturation for implantation.

Adult↗
PubMed1983

The XX male. Clinical and theoretical aspects.

A male patient attending a fertility clinic was recognized as having an XX chromosomal constitution. The clinical and theoretical aspects of the XX male are discussed and note is made of some improvement in the understanding of the condition with the determination of the H-Y status of these individuals.

Adult↗
PubMed1980

Effect of the cholesterol content of small unilamellar liposomes on their stability in vivo and in vitro.

Small unilamellar neutral, negatively and positively charged liposomes composed of egg phosphatidylcholine, various amounts of cholesterol and, when appropriate, phosphatidic acid or stearylamine and containing 6-carboxyfluorescein were injected into mice, incubated with mouse whole blood, plasma or serum or stored at 4 degrees C. Liposomal stability, i.e. the extent to which 6-carboxyfluorescein is retained by liposomes, was dependent on their cholesterol content. (1) Cholesterol-rich (egg phosphatidylcholine/cholesterol, 7:7 molar ratio) liposomes, regardless of surface charge, remained stable in the blood of intravenously injected animals for up to at least 400min. In addition, stability of cholesterol-rich liposomes was largely maintained in vitro in the presence of whole blood, plasma or serum for at least 90min. (2) Cholesterol-poor (egg phosphatidylcholine/cholesterol, 7:2 molar ratio) or cholesterol-free (egg phosphatidylcholine) liposomes lost very rapidly (at most within 2min) much of their stability after intravenous injection or upon contact with whole blood, plasma or serum. Whole blood and to some extent plasma were less detrimental to stability than was serum. (3) After intraperitoneal injection, neutral cholesterol-rich liposomes survived in the peritoneal cavity to enter the blood circulation in their intact form. Liposomes injected intramuscularly also entered the circulation, although with somewhat diminished stability. (4) Stability of neutral and negatively charged cholesterol-rich liposomes stored at 4 degrees C was maintained for several days, and by 53 days it had declined only moderately. Stored liposomes retained their unilamellar structure and their ability to remain stable in the blood after intravenous injection. (5) Control of liposomal stability by adjusting their cholesterol content may help in the design of liposomes for effective use in biological systems in vivo and in vitro.

Animals↗
PubMed1977

Transmembrane migration ('flip-flop') of cholesterol in erythrocyte membranes.

After exchange with [14C]cholesterol-labelled plasma lipoproteins for 0.5-4h, erythrocytes were extracted with bile-salt solutions. The extracted cholesterol (mainly from the outside of the erythrocyte membrane) had the same specific radioactivity as the residual sterol. Thus cholesterol equilibrates rapidly (half-time less than 1 h) between the two sides of the membrane.

Animals↗
PubMedDate not supplied

Funding the future.

Explore the source record for details and available documents.

Education, Nursing↗