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Biomedical subjects

R G Edwards

Publications and source records attributed to R G Edwards.

At least 181 records · Page 10Linked to original sources
PubMed1983

Current status of in-vitro fertilisation and implantation of human embryos.

Between October, 1980, and April, 1983, embryos fertilised in vitro were replaced in the uteri of 1200 women. The "clinical" pregnancy rate rose from 16.5% from October, 1980, until September, 1982, to almost 30% in 1983. The proportion of pregnancies ending in abortion varied from 25-35%. Factors favourably modifying implantation rate were maternal age of under 40 years, priming with clomiphene alone, and the replacing of more than one embryo in the uterus. The replacing of two or more embryos, increasing maternal age, a poor obstetric history, and high levels of follicular oestrogens raised the chances of abortion.

Abortion, Spontaneous↗
PubMed1983

Interference in the radioallergosorbent test by antibody light chains in rabbit urine.

Immunological techniques have been used to identify and quantitate rabbit antibody light chains in the urine of rabbits. The influence of these light chains on the radioallergosorbent test (RAST) used for the diagnosis of laboratory animal allergy to rabbit urinary protein allergens is described. The presence of IgG antibody specific for rabbit derived antigens in human serum has been confirmed.

Animals↗
PubMed1983

Field investigations of noise reduction afforded by insert-type hearing protectors.

NIOSH conducted field investigations in 1977 and 1981 to determine the actual noise reduction afforded to industrial workers who used insert-type hearing protectors (earplugs) daily. In-situ attenuation tests of 420 workers at 15 industrial plants were conducted to determine the noise reduction provided by earplugs as they were worn during the workday. The workplace results, when compared to manufacturers' best-fit laboratory test results, indicated that 50% of the workers tested were receiving less than one-half the potential attenuation of the earplugs.

Audiometry↗
PubMed1983

Prevalence and diagnosis of laboratory animal allergy.

A survey of the prevalence of laboratory animal allergy to rats, mice, guinea pigs and rabbits among sixty-nine animal workers and 308 other subjects on a pharmaceutical research site revealed a 22% prevalence of laboratory animal allergy among the animal workers. The overall prevalence of atopy was 67% in persons with allergy to laboratory animals. This was significantly greater than the 31% prevalence in other animal workers. Skin-prick tests and specific IgG and IgE assays to urinary protein extracts strongly correlated with the occurrence of laboratory-animal allergy and would appear to have diagnostic value. However, a number of clinically diagnosed laboratory-animal-allergy subjects gave no evidence of immunological response to the urinary allergens and wider diagnoses may have to be applied in these cases.

Allergens↗
PubMed1983

The development and validation of radioallergosorbent tests for the detection of specific human IgE antibody directed against laboratory animal urinary proteins.

Radioallergosorbent tests (RAST) using urinary proteins from mice, rats, guinea pigs and rabbits have been developed and used in the diagnosis of laboratory animal allergy (LAA). Of the 273 subjects tested, 15 had been previously diagnosed as laboratory animal allergic and 8 of these (53%) gave one or more positive RAST results. Of the 258 symptom-free individuals, only 9 (3.5%) had one or more positive RAST. Of these 9, 7 had previously worked with animals or had occupational exposure to the appropriate species; the remaining 2 individuals had only some pet exposure. RAST was, therefore, of value in the diagnosis of LAA. During the development of these RAST assays, several sources of potential error were identified. Modest titres of total IgE (600 IU/ml and above) were found to influence the specific RAST index observed and lead to false positive results. The presence of human IgG antibody specific for rabbit serum proteins was also identified in four sera, and was responsible for interference in the rabbit urinary protein RAST system.

Animals↗
PubMed1983

Laboratory animal allergy: the measurement of airborne urinary allergens and the effects of different environmental conditions.

Casella Simquad air samplers, with 0.5 microM cut-off filters, were employed to sample the air in a laboratory animal house environment. The extracts obtained were assayed for laboratory animal urinary protein allergens using the inhibition radioallergosorbent test (RAST inhibition). The results showed that the collection and assay methods were of value and studies were extended to the influence of air change rates and humidity on airborne allergen levels. Reducing the air changes increased allergen levels, whilst increasing the humidity from 54% to 77% caused a significant reduction in allergen levels.

Aerosols↗
PubMed1983

Follicular steroids as a prognosticator of successful fertilization of human oocytes in vitro.

Oocytes were collected by aspiration of preovulatory follicles from 55 women. The preovulatory rise in LH was monitored in urine using the Hi-Gonavis (Mochida Pharmaceuticals) technique. Patients were treated either during the natural cycle or after the induction of ovulation with clomiphene citrate. After collection and culture, the oocytes were inseminated with the spermatozoa of the husband. The levels of progesterone, oestradiol-17 beta and androstenedione in the clear follicular fluid were measured by radioimmunoassay. A multivariate analysis containing these three hormone levels together with two ratios of progesterone with each of the other hormones indicated reasonable discrimination between the oocytes which fertilized and those which remained unfertilized after insemination. The discriminant analysis suggested that the fertilization of the oocytes could have been predicted on the basis of these hormonal profiles with a success rate which exceeded 90%.

Androstenedione↗
PubMed1982

Development and use of three new radioallergosorbent tests in the diagnosis of penicillin allergy.

The synthesis and characterisation of three novel reagents for use in the radioallergosorbent test (RAST) for the diagnosis of penicillin allergy are described. The antigenic determinants involved are the benzyl penicillanyl, thiol-linked benzyl penicillenate and thiol-linked penicillamine. These reagents, and also one specific for the benzyl penicilloyl group, have been used to evaluate the sea of subjects suspected of suffering from penicillin allergy and to explore the aetiology of the respiratory dyspnoea experienced by some workers exposed to penicillin-containing dusts. The use of these reagents, while confirming the importance of the penicilloyl or major determinant of penicillin allergy, has shown that there is heterogeneity in the IgE response of penicillin-allergic patients and some patients have IgE antibody specific for one or more of the new determinants only. These reagents will, therefore, increase diagnostic capabilities. Their use has also confirmed that the disorder induced by occupational exposure to penicillins is not primarily mediated by IgE antibody specific for allergenic determinants represented by any of the available reagents.

Chemical Phenomena↗
PubMed1982

Development and use of radioimmunoassays for the detection of human IgG antibodies to laboratory animal urinary proteins.

A radioimmunoassay method for the detection of human IgG antibodies to laboratory animal urinary proteins has been developed using partially purified protein fractions prepared from crude urine extracts by gel filtration. The proteins from the four species, mouse, rat, guinea pig and rabbit, were labelled with 125I and used in an antigen binding assay employing a sepharose-linked staphylococcal protein A immunosorbent. Results, expressed as arbitrary units of specific IgG per unit serum, show antibodies to one or more species present in 57% of current animal workers compared with 6% of non-animal workers.

Animals↗
PubMed1981

The growth of human preimplantation embryos in vitro.

The parameters of the growth of human embryos in vitro between fertilization and the blastocyst are described. The data on the cleavage of embryos were subjected to statistical analysis. All the pronucleate eggs examined had two pronuclei. There was no evidence of any oocyte with three or more pronuclei, except in one examined 3 days after insemination, which may have been degenerating. Most eggs which were unfertilized remained in metaphase of the second meiotic division, with an extruded polar body. Spermatozoa were found embedded deeply in the zona pellucida of unfertilized and pronucleate eggs. A total of 417 embryos cleaved in vitro. Many were in the two-cell stage by 28 hours, four-cell stage at 43 hours, and eight-cell stage at 54 hours. Cleavage patterns were regular in the great majority. Compaction began at the 16 cell stage; the blastocyst began to form between 4 and 5 days after fertilization. Forty-two embryos were examined sufficiently often to make a statistical analysis of their growth in vitro. The mean doubling time of the cells was 15.82 hours approximately. Estimates of the mean midstage times for each stage of division were calculated. The results are discussed in relation to the cure of infertility by replanting human embryos, to the possibility of chromosomal and other disorders arising in the embryos, and to potential scientific studies on early human development.

Blastocyst↗
PubMed1981

Test-tube babies, 1981.

Between fifteen and twenty babies will be born this year after the in vitro fertilization of human eggs. Many of the essential steps now have high rates of success, including the recovery of preovulatory oocytes, and fertilization and embryo cleavage in vitro. Implantation of the embryo following its replacement in the mother remains the major difficulty. Some implications of the work are discussed.

Adult↗
PubMed1980

Establishing full-term human pregnancies using cleaving embryos grown in vitro.

The establishment of human pregnancies by the use of fertilization in vitro and placing cleaving embryos into the uterus is described. Preovulatory oocytes were aspirated at laparoscopy from the ovaries of patients soon after the beginning of the mid-cycle surge of luteinizing hormone (LH) during the natural cycle. The LH surge was identified by assaying 3-hourly samples of urine, and measurements of oestrogens in 24-hour samples were used to assess follicular growth. The surge of LH was identified in 68 patients and it showed a diurnal rhythm. Preovulatory oocytes were aspirated from most of the patients. Fertilization and cleavage occurred in 34 instances, and 32 embryos were put into the mother via the cervical canal. Four patients became pregnant. There were indications that a diurnal rhythm played a role in establishing cleaving embryos, each of the four pregnancies occurring when the embryos were placed in late evening. Each of the pregnancies resulted from oocytes which were aspirated from their follicles 24 hours or longer after the LH surge began. Details are given of three abortive pregnancies in patients given gonadotrophins to stimulate the maturation of of oocytes used for fertilization in vitro.

Chorionic Gonadotropin↗