Laser light transmission and laser Doppler blood flow measurements on the human, rat and guinea pig cochlea.

In order to test the applicability of laser-Doppler flowmetry in monitoring cochlear blood flow clinically, the thickness and the helium-neon laser light transmission of specimens of human, rat and guinea pig promontory bone and human skin were determined. Furthermore, comparative laser-Doppler measurements were taken from the promontory in patients, rats and guinea pigs. Due to the different thicknesses of the promontory bone in different species, the light transmission was found to be considerably higher for the animal cochlea (rat, 15%; guinea pig, 6.6%) than the human cochlea (1.7%). However, a clearly higher laser-Doppler signal was recorded from both the human and the rat cochleas as compared with the guinea pig. The relative laser light attenuation by the human skin specimens corresponded to that of the human promontory bone. The findings are discussed with regard to the suitability of the laser-Doppler method for blood flow measurements in the human cochlea.

The effect of combination chemotherapy on ovarian, hypothalamic and pituitary function in patients with breast cancer.

Treatment of breast cancer by combination therapy induced luteal insufficiency, anovulatory cycles and sometimes hypergonadotropic amenorrhea in premenopausal women with previously normal mentrual cycles and ovarian function. In chemotherapy induced amenorrhea 17 beta-estradiol levels were those found in ovarectomised or postmenopausal women. Chemotherapy affected the ovary itself and not the hypothalamus or pituitary, the negative feedback mechanisms remaining intact. The ovary of perimenopausal patients was much more sensitive to cytotoxic drugs; following a short time chemotherapy hypergonadotropic amenorrhea invariably developed and the ovary seemed to be again the prime site of action. Postmenopausal patients continued to have physiologically high LH and FSH plasma concentrations and low plasma levels of prolactin and 17 beta-estradiol under cytotoxic treatment.

[Hormonal pattern in premenopauseal cycles (author's transl)]. / Hormonanalytische Untersuchungen bei Zyklen in der Prämenopause.

By serial determinations of plasma LH, FSH, progesterone and estradiol-17beta as well as total gonadotropines, total estrogens and pregnanediol in 24 h urine samples it was possible to classify 19 cycles of premenopauseal women, aged 44-50 years, into two groups. The first group showed ovulatory cycles with partially shortened hyperthermic phases in the basal body temperature curves, slightly elevated levels of FSH and diminuished estradiol-17beta, pregnanediol and progesterone concentration, indicating the beginning insufficiency of the ovarian function. The second group was characterized by several times above normal elevated FSH and somewhat less elevated LH levels significantly lowered estradiol-17beta and only basal progesterone and pregnanediol concentrations. The ovulatory transitional cycles explicated a nearly normal fluctuation pattern which was completely abolished in the anovulatory cycles.