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Biomedical subjects

E Telfer

Publications and source records attributed to E Telfer.

11 recordsLinked to original sources
PubMed1991

Impact of exogenous progesterone on ovarian follicular dynamics and function in mice.

Raising progesterone concentrations in young adult mice by subcutaneous implants resulted in ovulation being blocked and the cessation of oestrous cycles. The effect of this treatment on the numbers and dynamics of preantral follicles during 36 days of treatment was studied using a compartmental model to analyse differential follicle counts. Changes in growth and/or death rates were detected at all stages of follicular development. An increased rate of growth through preantral stages was predicted in the treatment group when compared with the controls, but most of these follicles did not reach the antral stage of development as an increased death rate was observed at large preantral stages (stage IV). Antral follicles were formed in the treatment group, but all succumbed to atresia. Increased atresia in the antral population of follicles in the treatment group was observed directly.

Animals↗
PubMed1990

Temperance.

The kind of temperance discussed is the virtue of moderation concerning the pleasures of eating and drinking. A person lacks this moderation if either his desire for such pleasures causes conflicts with his own standards of appropriate behaviour or the standards themselves attach too much importance to the pleasures concerned. Opinions vary about the proper status of these pleasures, but people surely value them too highly if they place them above their health or the moral duty not to cause unnecessary suffering. Temperance concerns medicine because of its connection with health, ethics because it involves not only the good life for the individual but also the welfare of other creatures.

Attitude to Health↗
PubMed1990

Morphological study of cultured preantral ovarian follicles of mice after transplantation under the kidney capsule.

Isolated ovarian follicles taken from 10-day-old mice and cultured in collagen gel for 5 days, in the presence or absence of serum, were transplanted under the kidney capsule of ovariectomized mice. Hosts showed vaginal opening within 5 days and cornified vaginal smears by 9 days. Follicles proceeded to Graafian stages and luteinization occurred. Ovulation was not observed and oocytes degenerated within the luteinized follicle. Theca formation was preceded by the appearance of blood vessels within the graft. In-vitro fertilisation of harvested oocytes resulted in embryos.

Animals↗
PubMed1990

Extra-ovarian production of mature viable mouse oocytes from frozen primary follicles.

Isolated primary mouse follicles can be frozen successfully and thawed in the presence of 1.5 m-DMSO. Similar proportions of freshly collected and frozen-thawed primary follicles undergo folliculogenesis in the absence of other ovarian tissue. Some of the mature oocytes recovered from these follicles were fertilized in vitro and, after transfer to pseudopregnant recipients at the 2-cell stage, developed into live young. Cryopreservation and extra-ovarian development of immature follicles provide a unique opportunity to store large numbers of female gametes.

Animals↗
PubMed1989

Ovarian cyclicity and follicular recruitment in unilaterally ovariectomized mice.

Halving the numbers of follicles in young adult mice by unilateral ovariectomy resulted in compensatory Graafian follicle growth with a reduction by about 25% of the expected number of oestrous cycles. The impact of the operation on the numbers and dynamics of preantral follicles during the first 2 months after ovariectomy was studied using a compartmental mathematical model to analyse differential follicle counts. There were changes in growth and/or death rates at all stages of follicle development, and the patterns emerging were time-dependent. The rate of follicle survival from the pool of unilaminar stages was paradoxically reduced, but those forming two granulosa cell layers continued to develop towards Graafian size. As the frequency of follicle death declined, the numbers of healthy large preantral and antral stages in unpaired ovaries rose to approach those in pairs of age-matched control ovaries, suggesting that follicles otherwise undergoing atresia were being rescued. In the long-term, follicle dynamics after unilateral ovariectomy at young ages did not appear to compromise fecundity seriously.

Animals↗
PubMed1989

Quantitative study of the development of isolated mouse pre-antral follicles in collagen gel culture.

Follicles were isolated from the ovaries of 10-day-old C57BL6/CBA F1 hybrids by mechanical and enzymic treatment, embedded in a collagen-gel matrix to maintain the 3 dimensional integrity of the follicle and cultured for up to 14 days. Gels were removed at various times during the culture period and prepared for histology. Follicles grew from unilaminar to multilaminar stages within 6 days of the culture period. A more detailed assessment of growth by counting follicles at different stages and measuring oocyte and follicle diameters showed that follicle growth was maintained for up to 14 days in culture. Initially the proportion of unhealthy follicles was high but this declined after 6 days in culture.

Animals↗
PubMed1988

The number of clonal precursors of the follicular epithelium in the mouse ovary.

The number of clonal precursors of granulosa cells in mouse ovarian follicles has been estimated using a technique based on the phenomenon of random X-chromosome inactivation of somatic cells and the use of an X-linked alloenzyme variant of the glycolytic enzyme PGK-1. The granulosa cells of follicles were oligoclonal in origin and founded by a small number of cells (about 5) which was consistent with histological observations. When the analysis was extended to two subcompartments of the follicle, the mural and cumulus granulosa cells, the results indicated that the cumulus and mural granulosa cells had a common origin.

Animals↗
PubMed1987

The kinetics of pre-antral follicle development in ovaries of CBA/Ca mice during the first 14 weeks of life.

The kinetics of ovarian follicle growth and death have been estimated in virgin inbred mice using a compartmental model and data obtained from differential follicle counts in histologically sectioned ovaries. The results showed that both growth and death rates are dependent on stage of development, defined by the compartments, and age, indicated in the model by step functions with transitions at 20 and 60 days of age. During the initial phase of postnatal ovarian development, large numbers of follicles disappeared from the non-growing reserve as a result of the combined effects of follicle death and recruitment into the growing population. The reduced death rate after 20 days led to a secondary peak in the numbers of follicles at intermediate stages. In contrast to these fluctuations, the number of large follicles, including pre-ovulatory types, were remarkably constant after this age and the rate of outflow stabilized at two to three follicles per day after an initially high value. This rate is sufficient for the normal ovulation rate in a 4-day oestrous cycle with a small surplus of follicles undergoing atresia. The rates of migration through successive stages of development decreased during ageing as large follicles began to emerge at the approach of puberty: this result may indicate that the recruitment of small growing follicles is influenced by a feedback effect.

Age Factors↗
PubMed1987

A quantitative cytological study of polyovular follicles in mammalian ovaries with particular reference to the domestic bitch (Canis familiaris).

The incidence of polyovular types in the growing follicle population was estimated using quantitative cytology. Of 15 species studied, polyovular follicles were recorded in the following species and in ascending order of abundance: rabbits, rhesus monkeys, humans, cats, dogs. The incidence in bitches was 14% in animals aged 1-2 years but only 5% at 7-11 years old. The frequency of the various types of polyovular preantral follicle varied inversely with the numbers of oocytes per follicle and the probability of finding a follicle with more than 5 oocytes was remote. In young ovaries the frequency was constant in the early stages of growth but decreased in the largest preantral stage. The pattern in ageing ovaries was, by contrast, one of declining frequency such that few if any polyovular types completed development. The ovary of the ageing bitch was also characterized by a higher incidence of degenerating follicles and a much smaller pool of primordial stages. Polyovular follicles were larger than uniovular types at comparable stages which were defined by the number of granulosa cell layers. Their oocytes were smaller but the overall ooplasmic mass was increased with a corresponding increase in the mass of granulosa cells.

Aging↗
PubMed1976

Justice, welfare and health care.

Miss Telfer offers a new analysis, classifying health care into four systems, only one of which, the "laissez-faire" type, is unlikely to be acceptable today. The other three systems are defined here as "liberal humanitarian", "liberal socialist" and "pure socialist." Each is analysed for its content and for the views of its protagonists and antagonists. On these issues no dogma is proclaimed as the author says she has sought to "bring out some of the principles at issue in any discussion of the rights and wrongs of socialized medicine". This journal is surely the proper place for such a discussion as the worlds of the politician, of the economist, of the doctor and of the patient come to a point in the philosophies behind the aspect of medical ethics exemplified in the provision of medical services by the state. Miss Telfer also glances down the byways of the medicine of the market place.

Delivery of Health Care↗