Biomedical subjects
Publications and source records attributed to S Thor-Wiedemann.
Rationalization in clinical care has reached its limits. Facing the need of further reducing health care costs it is relevant to reflect which diagnostic and therapeutic procedures are justified considering the public economic interests. A prioritized list of covered medical care requires a consensus of physicians, insurance companies and patients organizations on the basis of evidence-based medicine.
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Cell proliferation in the ovaries of 5 Beagle dogs was studied by autoradiography after pulse labelling with (3H)-thymidine during different periods of proestrus and early estrus. Indices of labelling and of necrosis were determined for different follicle types grouped according to their stages of atresia. Cell proliferation became most obvious during early proestrus in antral and in Graafian follicles, and during the periovulatory period in preantral follicles. By contrast, low labelling indices appeared in all follicle types during the middle of proestrus. All follicle types demonstrated a continuous decrease in labelling from early to late atresia with the exception of the granulosal layer of antral follicles during the periovulatory period. While many necrotic granulosal cells were found in antral follicles during the first 6 days of proestrus, there were few during the periovulatory period. Even Graafian follicles displayed necrotic granulosal cells now and then. It may be concluded that (1) intact ovarian follicles can show subtle changes indicating the beginning of atresia, and (2) during the proliferative phase of a long estrous cycle cell replication in the ovary is characterized by two bursts at the beginning and at the end of this period.
Cell proliferation in the principal target organs of the ovary was studied in 7 beagle dogs during proestrus, early estrus, secretory and regressive metestrus. Pulse labelling with (3H)-thymidine and autoradiography were applied and labelling indices were determined. Organs with squamous and with glandular epithelium except the mammary gland showed a proliferation peak during early proestrus, the incidence of labelling being higher in organs with squamous epithelium. During early proestrus the intensity of labelling decreased in organs with squamous epithelium in the following order: vulva, vagina, portio vaginalis, and portio supravaginalis. At this time cell replication was higher in the superficial glands of the cervix and corpus uteri as well as the circular layer of the myometrium compared with values from the basal glands or the longitudinal layer. The steepest decline of the proliferative activity occurred between the proestrous period. While some labelled cells were observed during secretory metestrus, labelling was almost absent during regressive metestrus. By contrast, the mammary gland began to develop at the periovulatory period and was at the height of its proliferative activity during secretory metestrus. It is concluded for species with a long estrous cycle that: (1) the rate of cell replication in the vulva, vagina, uterus and oviduct is at its peak at the beginning of the estrous cycle and declines during proestrus; (2) as compared to observations in species with short estrous cycles, cell proliferation is very low during metestrus.