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Biomedical subjects

I L Craft

Publications and source records attributed to I L Craft.

At least 55 records · Page 3Linked to original sources
PubMed1986

Cryopreservation of human spermatozoa: an assessment of methodology using rhodamine 123.

Rhodamine 123 fluorescent labeling of the human spermatozoal midpiece was used as a means of monitoring spermatozoal viability. This simple procedure was used in three separate studies to establish differential spermatozoal survival. Twenty ejaculates of reasonable quality were taken from men attending the Cromwell Hospital IVF Clinic. These were split three ways: cultured fresh at 37 degrees C as for IVF, or frozen/thawed and then cultured at 37 degrees C after freezing in either an egg yolk-free glycerol cryoprotectant or an egg yolk citrate medium. An expected overall difference in viability between fresh and frozen/thawed spermatozoa was observed, with no significant difference between the cryoprotective abilities of the two cryoprotectants studied. Four ejaculates were either frozen/thawed in the egg yolk-free cryoprotectant or cultured fresh, and both were subsequently stored at room temperature. Fall-off in frozen/thawed spermatozoal viability was more rapid than for the fresh cultured spermatozoa, although all spermatozoa survived longer at room temperature than at 37 degrees C. Five ejaculates were split to culture their spermatozoa at 37 degrees C in media containing either human or bovine serum albumin, or human fetal cord serum. BSA proved to be the least successful of protein supplements in maintaining spermatozoal viability, with HSA and cord serum giving rise to comparable viability of spermatozoa cultured in each. RH 123 is recommended as an alternative means of assessing human spermatozoal viability, and the results arising from the use of this technique here are discussed with their particular relevance to semen freezing and preparation in IVF centers.

Cell Survival↗
PubMed1986

An investigation of maternal and neonatal platelet function.

We have previously shown that the human placenta possesses a potent platelet antiaggregatory activity which is probably due to an ADPase. This led us to investigate platelet aggregation (in response to: adenosine diphosphate; adrenaline; collagen) in maternal blood samples obtained pre- and post-delivery and in cord blood at the time of delivery. Platelet aggregation in maternal samples did not differ significantly pre- and post-delivery, nor did it differ significantly from platelet aggregation observed in age-matched, non-pregnant women. On the other hand, platelets obtained from cord blood samples were insensitive to adrenaline even when very high concentrations (100 mumol/l) of this agonist were used. This lack of response to adrenaline could be overcome by incubation of cord platelet rich plasma (PRP) with sub-aggregatory doses of collagen or ADP or by standing PRP at room temperature for 2-3 h. ADP-induced aggregation was also diminished in cord PRP samples but this was only significant at the lowest ADP concentrations. The physiological significance of these findings is unclear but it may be of relevance that plasma catecholamine levels are high in neonates. Some adults show a defect of aggregation with absence of response to adrenaline, suggesting that neonatal platelet function patterns may persist in some adults.

Adenosine Diphosphate↗
PubMed1983

Adenosine diphosphate-degrading activity in placenta.

1. The degradation of ADP by the placenta and umbilical artery was investigated. 2. Supernatants from incubations of finely chopped placental and umbilical arterial tissue were incubated with [14C]ADP for various durations from 0 to 30 min. 3. Products of ADP degradation were separated by thin-layer chromatography and radioactivity incorporated into each product was measured. 4. Placental supernatants induced a more rapid degradation of ADP than the umbilical artery supernatants. The main product of ADP degradation by placental supernatants at 30 min was adenosine, whereas that of umbilical artery was AMP. 5. This conversion by placenta of ADP, a potent platelet aggregator and vasoconstrictor, into adenosine, a potent platelet anti-aggregator and vasodilator, may be important in the maintenance of perfusion of the foetoplacental unit.

Adenosine↗
PubMed1983

Severe ulcerative colitis during successful pregnancy.

A 31-year-old patient presented with fulminant colitis during the 27th week of her first pregnancy. Despite failed medical treatment, colectomy was delayed because of the gravid uterus. A healthy child was delivered at 32 weeks by caesarian section, but a postoperative ileus appeared to induce transient colonic dilatation. A colectomy was performed 10 days post-partum. Both mother and child survived.

Adult↗
PubMed1980

Combined estrogen and progestogen for the menopause.

A single-blind pilot study using combined estrogen and progestogen therapy was undertaken in 25 patients for a period of six months in an attempt to evaluate symptomatic control, the acceptability or otherwise of bleeding patterns, and the effect on endometrial pathology. Two different progestogens were employed, i.e. norgestrel and norethisterone acetate, and each was given in combination with estradiol valerate in a cyclical and a continuous regime. Symptomatic control was good in all groups, but there was a mild recrudescence of some symptoms during the tablet-free interval in the cyclical groups. Regular withdrawal bleeding was reported in almost all cases receiving cyclical therapy, and unscheduled bleeding was noted in those on continuous regimes. Endometrial hyperplasia did not occur following treatment in any of the groups, and there was a return to the normal histology in two patients in whom hyperplasia existed prior to treatment. These results support the view that endometrial hyperplasia is least likely to occur if progestogens are administered in combination with estrogen. There were no obvious differences between the effects of the two progestogens.

Climacteric↗
PubMed1979

Facilitation of suction termination using extra-amniotic prostaglandins in gel.

Extra-amniotic prostaglandin E2 (PGE2) suspended in a slow release gel (Tylose) was instilled in 35 patients prior to a planned surgical termination in an attempt to dilate the cervix, minimize cervical trauma, and reduce the possible risk of cervical trauma, and reduce the possible risk of cervical incompetence and its sequelae. Dilatation occurred in all patients to a minimum of 8 mm and 74% aborted before surgical evacuation performed 6 to 24 hours after injection. No serious side effects occurred. Extra-amniotic PGE2 in gel should be considered as a primary procedure when the cervix is obviously immature on examination. If the cervix is found to be tight and unyielding at surgical dilatation, the latter procedure should be dicontinued and PGE2 in gel injected.

Abortion, Induced↗
PubMed1979

Routine induction of labour with extra-amniotic prostaglandin E2 in a viscous gel.

Prostaglandin E2, 350 microgram dispersed in a viscous gel, tylose, was introduced into the extra-amniotic space as a single dose in 285 patients to induce labour. With a favourable cervix, 82 per cent of multiparae and 50 per cent of primiparae were successfully induced. With unfavourable induction features, the success rates were 48 per cent and 24 per cent respectively. In the remaining patients, all but four were successfully delivered when intravenous oxytocin was also used. The method was safe, simple and inexpensive and had many advantages for patients and nursing staff.

Amnion↗
PubMed1977

Variations in plasma steroid and prostaglandin concentrations during human pregnancy.

Radioimmunoassay of sex steroids and prostaglandins was performed on plasma obtained from 10 uncomplicated primigravid subjects at a stated time of the day at varying stages of gestation. Prostaglandin E2 (PGE2), prostaglandin F2alpha (PGF2alpha), oestrone and oestriol concentrations reached a peak a few weeks before term and then declined. Progesterine, 17-hydroxyprogesterone and oestradiol increased during pregnancy particularly after 32 weeks. In two normal patients repeated blood samples were taken throughout the day at weekly intervals in late pregnancy for sex steroid assays to evaluate the variation of concentrations with the time of sampling and the significance of changes in mean concentrations of different steroids with approaching parturition. Marked variability was found in the levels of different steroids during the day. Plasma oestriol values were lowest at 8.00 a.m. in one patient sampled frequently. A marked decrease in oestriol, oestrone, oestradiol and 17-hydroxyprogesterone was found in one patient prior to the onset of spontaneous labour. In another subject there was no decrease in concentrations of oestrogens or progestogens prior to induction of labour at term.

Circadian Rhythm↗