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Biomedical subjects

G B James

Publications and source records attributed to G B James.

13 recordsLinked to original sources
PubMed1993

Steroid secretion by human early embryos in culture.

The ability of in-vitro fertilized human embryos to secrete oestradiol in culture in the presence of precursor androgen was demonstrated in four independent cultures. Varying amounts of oestradiol were detected and secretion was observed as early as days 5-8 post-fertilization. The pattern of human chorionic gonadotrophin secretion was similar to oestradiol secretion for individual embryos. In one additional culture, secretion of oestradiol and progesterone was observed.

Chorionic Gonadotropin↗
PubMed1991

Effects of in-vitro exposure to HCG on subsequent HCG-responsiveness of human granulosa cells obtained following treatment with GnRH analogue and gonadotrophins: an in-vitro model for luteal phase support.

The pregnancy rate in patients undergoing assisted conception treatment following pituitary desensitization with GnRH analogue and ovarian stimulation with gonadotrophins has been reported to be higher when ovarian function is supported in the luteal phase by exogenous human chorionic gonadotrophin (HCG). In the present study, we have examined the effects of culturing monolayers of granulosa cells, collected from such patients at oocyte retrieval, for various time intervals in the presence or absence of HCG on their subsequent ability to secrete progesterone (P4) either spontaneously or in response to further challenge with HCG. When cultured in the absence of HCG, granulosa cells demonstrated a rapid decline in both the spontaneous P4 secretion rate and the ability to secrete P4 in response to HCG. Maintenance in the presence of HCG inhibited the rapid decline in ability to secrete P4 spontaneously and also significantly enhanced the ability to respond to subsequent HCG stimulation. These results suggest that HCG support in the luteal phase in GnRH analogue-treated patients may have a cellular basis for its action both in maintenance of P4 secretion and also in rendering the corpus luteum more sensitive to rescue by conceptus-derived HCG.

Buserelin↗
PubMed1987

Reversal of female sterilisation: a comparative study.

In 80 women who had reversal of sterilisation, a study was made of their clinical features at the time of sterilisation and of the factors related to successful outcome. Compared with controls at the time of sterilisation, the women requesting reversal were younger, of lower social class and of higher parity; in addition they were more likely to have an unstable relationship and to have been sterilised following a recent pregnancy. After reversal, intrauterine pregnancy occurred in 26/80 (32.5%) and ectopic pregnancy in 6/80 (7.5%), the majority of successful pregnancies occurring in younger women within one year of reversal following a non-destructive method of tubal occlusion. There was no evidence that techniques of management, including the use of an operating microscope, significantly influenced outcome, and controlled trials will be required to establish their efficacy.

Adult↗
PubMed1979

A cytogenetic survey of men being investigated for subfertility.

A study of 336 men attending a subfertility clinic but otherwise unselected, and a further 12 men studied as a part of the investigation of the female partner, revealed 10 with major chromosome anomaly and 3 with unambiguous chromosomal variants. In addition to those with sex chromosome aneuploidy, an extra, small marker chromosome and D/D Robertsonian translocations, anomalies which have been reported in other studies, there were 7 men with rearrangements, including a paracentric inversion of chromosome 7 and an X/21 reciprocal translocation. These would have been difficult or impossible to identify without good banded preparations, suggesting that such rearrangement may be more frequent in association with subfertility than was appreciated.

Adult↗
PubMed1966

The oxygen consumption of the placenta and foetal membranes in the sheep.

1. In anaesthetized sheep near term the O(2) uptake of the foetus from the placenta was reduced to zero either by replacing the foetus with a mechanical pump, or by ventilation of the foetus after delivery or in utero. When umbilical arterial and venous P(O2) were made equal, they were much less than maternal arterial P(O2).2. This difference in P(O2) was attributed to O(2) consumption both within the placental cotyledons and the extra-cotyledonary foetal membranes.3. The foetal membranes and cord in the sheep are supplied by branches of umbilical blood vessels and constitute an oxygen-consuming by-pass on the foetal side of the placenta.4. The O(2) consumption of individual placental cotyledons was measured in vivo.5. The combined O(2) consumption of the whole placenta and foetal membranes in vivo was a considerable fraction of foetal O(2) consumption.6. The consequences of these observations are discussed in relation to O(2) transfer across the placenta.

Animals↗