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Biomedical subjects

V N Bolton

Publications and source records attributed to V N Bolton.

At least 19 recordsLinked to original sources
PubMed1995

Superovulation, IGFBP-1 and birth weight.

In this study, the effect of superovulation on the circulating levels of insulin-like growth factor binding protein-1 (IGFBP-1) has been investigated. IGFBP-1 levels were measured in singleton pregnancies achieved either naturally (n = 203) or following superovulation, in-vitro fertilisation and embryo transfer (IVF-ET) with either pituitary desensitisation with buserelin and superovulation with human menopausal gonadotrophin (b/hMG) followed by IVF-ET (n = 15) or with clomiphene citrate and hMG (CC/hMG) followed by IVF-ET (n = 15, 1st trimester only). The circulating levels of IGFBP-1 were similar in all three groups during the first trimester, and in both normal and b/hMG pregnancies in the second, but were significantly higher during the third trimester in b/hMG pregnancies than in normal pregnancies (P = 0.0002). The birth weights were significantly lower in the b/hMG group (P = 0.04), but not in the CC/hMG group compared with natural conceptions. Gestational age at delivery was similar in control and b/hMG pregnancies, but significantly reduced in CC/hMG pregnancies (P = 0.04). These data suggest that pregnancies achieved following superovulation with b/hMG are associated with elevated levels of IGFBP-1 during the third trimester of pregnancy and reduced birth weight.

Adult↗
PubMed1993

Interactions between the embryo and corpus luteum.

A total of 102 patients who had become pregnant following in-vitro fertilization (IVF) and embryo transfer were studied at weekly intervals between 4 and 14 weeks gestation. The pregnancies were classified as follows: (i) normal singleton, n = 52; (ii) normal twin, n = 24; (iii) heterotopic, n = 4 (weeks 4-8 only); and (iv) anembryonic with a viable intra-uterine singleton, n = 22. The serum concentrations of human chorionic gonadotrophin (hCG), Schwangerschaft protein-1 (SP-1) and pregnancy-associated plasma protein-A (PAPP-A), oestradiol and progesterone were measured. The mean serum concentrations of HCG, SP-1 and PAPP-A were significantly less in heterotopic than in singleton, singleton/anembryonic or twin pregnancies (P < 0.01-0.05), while those of progesterone and oestradiol were not different at any time. There were no significant differences between the serum concentrations of any of the substances analysed in singleton/anembryonic and singleton pregnancies, but the concentrations of all the substances analysed were significantly greater in twin pregnancies from as early as 7 weeks (P < 0.01-0.05). These data show that in heterotopic pregnancies trophoblast function is reduced, as suggested by the lower concentrations of the placental proteins. Despite this the concentrations of oestradiol and progesterone, derived predominantly from the corpus luteum between 4 and 8 weeks, are equivalent to those found in twin pregnancies, and greater than those found in singleton and singleton/anembryonic pregnancies. These findings support the notion that although HCG may rescue the corpus luteum it does not subsequently have a direct effect on its function, and suggest that the embryo may influence corpus luteum function.

Chorionic Gonadotropin↗
PubMed1992

Preimplantation diagnosis of a human beta-globin transgene in biopsied trophectoderm cells and blastomeres of the mouse embryo.

The preimplantation diagnosis of a HbSA-globin transgene in biopsied trophectoderm cells and blastomeres in embryos using a transgenic mouse model for the trait of human sickle-cell anaemia has been undertaken. A sensitive procedure was developed for the amplification of the human beta-globin gene sequence flanking the sickle mutation. Polymerase chain reaction (PCR) assays were undertaken on one to five biopsied trophectoderm cells and isolated blastomeres of the preimplantation mouse embryo. After biopsy the blastocysts were cultured whilst the cells were analysed for the presence of the transgene, and a high proportion (82-91%) were viable as assessed by the presence of a blastocoele cavity within a 5-h period. The majority of the biopsied cultured blastocysts were frozen and used to confirm the diagnosis; 90 biopsied cultured blastocysts were transferred to pseudopregnant recipients and 34% established pregnancy. Material from day 13.5 post-coitum fetuses was also used to confirm the original diagnosis. The time (4-5 h) required to carry out the analysis obviates a need for extended culture or cryopreservation of the biopsied embryo. In individual experiments under optimal conditions, the presence of the transgene in biopsied cells was detected with 100% accuracy, and the PCR analysis was sensitive at the 1-cell level. The overall success rate of diagnosis and confirmation of the presence or absence of the human beta-globin sequence in the biopsied embryo was 70%. Over the entire experimental period (14 months) DNA contamination from a variety of sources did occasionally occur; the methods used to overcome this problem are discussed.

Anemia, Sickle Cell↗
PubMed1992

Laparoscopic zygote intrafallopian transfer using augmented local anesthesia.

In this study, 29 laparoscopic ZIFTs were performed in 21 patients using local anesthesia augmented with intravenous analgesia. The technique was well tolerated; significant discomfort arose only when the fallopian tubes were manipulated and was minimized by transferring zygotes to one tube only. Seven pregnancies resulted, of which three have delivered and one is ongoing.

Adult↗
PubMed1991

Pregnancies after in vitro fertilization and transfer of human blastocysts.

In a study of 29 cycles of IVF, ET was performed on day 5 after oocyte recovery when embryos had developed to the morula/blastocyst stage. Three preclinical pregnancies and three live births resulted (2 singleton and 1 twin), giving a viable PR per ET of 10%. It is concluded that while day 5 ET may well be important in terms of embryo biopsy for the preimplantation diagnosis of genetic disease, day 2 ET remains preferable for therapeutic IVF. Although these data would not support the introduction of day 5 ET into routine therapeutic IVF, delayed ET should be considered as an alternative approach to preimplantation diagnosis. Indeed, because the latter will generally involve the treatment of normal, fertile couples, it might be predicted that embryo survival rates, and thus the rate of pregnancy after day 5 ET, would be better than those presented here.

Embryo Transfer↗
PubMed1991

Detection of human papillomavirus DNA by PCR in semen from patients with and without penile warts.

OBJECTIVES: To determine the prevalence of urethral HPV infection, as indicated by the presence of HPV DNA in semen, in males with and without penile warts. DESIGN: Prevalence study of HPV types 6/11 and 16 DNA using PCR and Southern blot hybridisation analysis of semen. SETTING: Department of Genitourinary Medicine, Blundell Street Clinic, Leeds General Infirmary and the Assisted Conception Unit (ACU) Kings' College, London. SUBJECTS: Patients attending the Genitourinary Clinic for treatment of sexually transmitted diseases including penile warts and males attending Kings' ACU for investigations of infertility. MAIN OUTCOME MEASURES: HPV DNA detected by polymerase chain reaction (PCR) and/or Southern blot hybridisation in semen. RESULTS: HPV DNA was detected by PCR in 23 of 27 (85%) specimens from patients attending the GUM clinic for treatment of genital warts and in one of two specimens from patients attending the clinic for other conditions. By Southern blot, nine (33%) of the 29 specimens from GUM clinic patients were HPV DNA-positive. HPV DNA was detected by PCR in 43 of 104 (41%) of specimens from males attending the ACU, whilst 70 of these tested by Southern blot hybridisation were all negative for HPV DNA. CONCLUSIONS: The data suggest that urethral HPV infections, as indicated by the presence of HPV DNA in semen, are prevalent in males with and without genital warts.

Blotting, Southern↗
PubMed1990

An evaluation of the hypo-osmotic sperm swelling test as a predictor of fertilizing capacity in vitro.

The ability of sperm to swell in hypo-osmotic conditions was examined in 211 semen samples from the partners of patients about to undergo oocyte retrieval for in-vitro fertilization (IVF). The test was performed using aliquots of semen, the remainder of which was then prepared for IVF. No significant difference was found, in either the percentage of swollen sperm or the type of swelling response, between samples that achieved fertilization in vitro and those that did not, or between any of the diagnostic categories of infertility (tubal damage, unexplained infertility, oligospermia). In samples which achieved fertilization in vitro there were correlations between sperm swelling and sperm motility (r = -0.51) and abnormal morphology (r = 0.33), but no such correlations were demonstrated in samples that failed to achieve fertilization. Moreover, there was no significant difference between the percentage of swollen sperm in semen (mean motility 64%), in samples immediately after preparation for IVF (mean motility 96%) or in capacitated sperm 24 h after preparation (mean motility 91%). These results demonstrate that the hypo-osmotic sperm swelling test does not assist in the prediction of the fertilizing capacity of human sperm in vitro.

Cell Membrane↗
PubMed1989

Development of spare human preimplantation embryos in vitro: an analysis of the correlations among gross morphology, cleavage rates, and development to the blastocyst.

Following in vitro fertilization, the criteria commonly used to select human embryos for transfer are the cleavage rate and gross morphology, the contention being that those embryos which divide more rapidly and have regular, spherical blastomeres are more likely to lead to a pregnancy. In order to assess the validity of this assumption, the development in vitro of spare embryos was investigated. Eggs and embryos were cultured in Earle's balanced salt solution containing 10% heat-inactivated patient's serum, and insemination was performed at 40 hr post human chorionic gonadotropin (hCG). At 82-90 hr post hCG, up to four embryos were transferred. Any spare embryos were cultured in the same medium for up to 6 days and scored daily for cell number and morphology using a "quality" scale of 4-1 according to degree of fragmentation and shape of the blastomeres. Of 317 fertilized eggs, 55 (17%) developed to the fully expanded blastocyst stage. The remaining embryos ceased development at the one-cell (6; 2%), two-cell (49; 15%), four-cell (110; 35%), eight-cell (61; 19%), and cavitating morula (36; 11%) stages. The relationship between developmental arrest and gross morphology is discussed.

Blastocyst↗
PubMed1989

An evaluation of semen analysis and in-vitro tests of sperm function in the prediction of the outcome of intrauterine AIH.

Twenty-nine couples with an average of 5 years of infertility were selected for treatment by intrauterine insemination of washed semen (AIH). The criteria for selection were (i) the female partner showed no detectable fertility disorders by routine screening; (ii) the male partner showed subnormal semen quality on conventional semen analysis. Ovulation was stimulated uniformly with clomiphene citrate and precipitated with human chorionic gonadotrophin (HCG). Inseminations were performed 31-32 h post-HCG, with the day of HCG determined by ultrasound monitoring of follicular development. The fertilizing capacity of the male partners' spermatozoa was tested in vitro using donated human oocytes and/or the zona-free hamster oocyte penetration assay. Up to eight cycles of AIH were alternated with cycles of natural intercourse. While no pregnancies occurred in the group during normal coital cycles, the AIH pregnancy rate was 17% per couple, but only 3% per insemination cycle. Four further pregnancies were achieved spontaneously in couples from the study group within 3 years of completion of the AIH therapy and four patients became pregnant following subsequent GIFT or IVF treatments. Neither of the in-vitro tests was helpful in predicting the outcome of AIH, spontaneous pregnancy nor of subsequent assisted conception procedures.

Adult↗
PubMed1989

Gamete intra-fallopian transfer combined with diagnostic laparoscopy: a treatment for infertility in a district hospital.

Gamete intra-Fallopian transfer (GIFT) was combined with a diagnostic laparoscopy on a routine operating list in a district general hospital. The equipment used was entirely portable. Operations were programmed 6-12 weeks in advance using a fixed ovarian stimulation regimen. Of 47 patients treated, 38 (81%) responded appropriately to stimulation. Of these, 23 had partners with normal semen parameters and 5 of 21 (24%) who had GIFT conceived. Two others were found to have tubal damage. Their eggs were transported to an in-vitro fertilization unit at another hospital. Both conceived after embryo transfer. In 15 couples, the semen was found to be sub-optimal and none of these became pregnant. GIFT can be performed in a district hospital, on a fixed schedule in conjunction with a diagnostic laparoscopy. The technique appears unsuitable for patients with suboptimal semen and the backing of an in-vitro fertilization unit increases pregnancy rates.

Clomiphene↗
PubMed1989

Temporal changes in the expression of the insulin-like growth factor II gene associated with tissue maturation in the human fetus.

The insulin-like growth factors are broadly distributed in the human conceptus and are thought to play a role in the growth and differentiation of tissues during development. Using in situ hybridization we have shown that a wide variety of specific cell types within tissues express the gene for insulin-like growth factor II at times of development from 18 days to 14 weeks of gestation. Examination of blastocysts produced by in vitro fertilization showed no expression, thus bracketing the time of first accumulation of IGF-II mRNA to between 5 and 18 days postfertilization. The pattern of IGF-II expression shows specific age-related differences in different tissues. In the kidney, for example, expression is found in the cells of the metanephric blastema which is dramatically reduced as the blastema differentiates. The reverse is also seen, and we have noted an increase in expression of IGF-II in the cytotrophoblast layer of the placenta with gestational age. The sites of expression do not correlate with areas of either high mitotic activity or specific types of differentiation, but the observed pattern of expression in the kidney, adrenal glands and liver suggests an explanation for the abnormally high IGF-II mRNA expression in developmental tumours such as Wilms' tumour.

Adrenal Cortex↗
PubMed1989

Are human spermatozoa separated on a Percoll density gradient safe for therapeutic use?

Motile morphologically normal human spermatozoa can be separated from semen by buoyant density centrifugation on Percoll (Pharmacia Fine Chemicals AB, Uppsala, Sweden) gradients. In this study, the authors have examined (1) the efficiency of washing procedures to remove contaminating Percoll particles from the separated spermatozoa, and (2) the potential of Percoll particles, which contain silica, to cause an inflammatory response when used for intrauterine insemination, or when introduced into the fallopian tube during gamete intrafallopian transfer (GIFT) procedures, as assessed by an intraperitoneal injection into mice. Although Percoll was phagocytosed at the injection site, and therefore cannot be presumed to be totally inert, no generalized inflammatory response was detected. A double spin and wash technique was found to remove most residual Percoll from the spermatozoa, as assessed by scanning electron microscopy. These results suggest that procedures involving the use of Percoll for the separation of human spermatozoa for in vitro fertilization, GIFT, or intrauterine insemination should include stringent washing protocols that will remove most, if not all, contaminating Percoll from the sample.

Cell Separation↗
PubMed1987

Pregnancies following in vitro fertilization and ultrasound-directed surgical embryo transfer by perurethral and transvaginal techniques.

Ultrasound-directed surgical ET is useful in patients with a history of difficult cervical (nonsurgical) transfer, and was performed without complications in the small group reported here. The technique is straightforward, and requires no greater expertise than that necessary for ultrasound-guided oocyte collection. However, further studies are necessary to assess its role in the routine transfer of embryos following IVF.

Adult↗
PubMed1987

The effect of morphology on the ability of human spermatozoa to penetrate zona-free hamster oocytes.

The effect of morphology on the ability of human spermatozoa to penetrate zona-free hamster oocytes was investigated using fractions of individual semen samples enriched for morphologically normal or abnormal spermatozoa, after separation by buoyant density centrifugation on self-generating Percoll gradients. Using this separation technique, the percentage of spermatozoa of normal morphology is greater in the lowermost 1 ml of the Percoll column (layer 1) than in the fraction recovered from higher up the column. Thus it was possible to compare two populations of spermatozoa from each semen sample in their ability to penetrate hamster oocytes. After normalizing the concentration of motile spermatozoa the mean hamster oocyte penetration rate was significantly higher with spermatozoa recovered from layer 1 (39 +/- 4%) compared with those recovered from layer 7 (21 +/- 4%), which suggests that morphologically abnormal spermatozoa do not have the same fertilizing capacity as those with normal morphology.

Animals↗