Biomedical subjects

R K Meyer

Publications and source records attributed to R K Meyer.

At least 37 records · Page 2Linked to original sources

PubMed1978

An efficient method to produce specific anti-actin.

The production of affinity column purified (specific) anti-actin is described. With the immunization scheme employed, all rabbits produced precipitating antibodies over several months, so that 30 mg specific anti-actin per rabbit could be isolated in 6 months. The antibodies against native and detergent denatured smooth muscle actin are characterized by immunodiffusion tests, staining of the I-band of isolated myofibrils and stress fibers in tissue culture cells, using indirect immunofluorescence.

Actins↗

PubMed1977

Corpus luteum and fetoplacental functions in monkeys hypophysectomized during late pregnancy.

The hormonal regulation of corpus luteum (CL) function during late pregnancy was studied in hypophysectomized monkeys. Between days 149-154 of gestation, 9 days after hypophysectomy, progesterone in the uteroovarian vein (UOV), uterine vein (UV) and peripheral circulation (P) averaged 179.7 ng/ml, 38.9 ng/ml and 5.5 ng/ml, respectively. Amniotic fluid prolactin ranged from 2150-6700 ng/ml and monkey chorionic somatomammotropin (mCS) in mothers carrying live fetuses ranged from 11.4-30.8 micrograms/ml in the UV and P. Prolactin and monkey chorionic gonadotropin in the UV and P were low or nondetectable as was mCS in 2 mothers carrying dead fetuses. CL function was further studied 7 and 39 days after removal of the fetus alone or both the fetus and placenta. Placental delivery was extremely variable, ranging from 2-greater than 63 days post-fetectomy. Although progesterone was not detectable in the P7 days after cesarean section in those animals in which both fetus and placenta were absent, surprisingly, progesterone was measurable in the UOV (range 1.6-48.2 ng/ml). At 39 days, progesterone was either nondetectable or very low. We have interpreted these data to mean: 1) neither the maternal pituitary gland nor a live fetus is necessary for placental or corpus luteum production of progesterone during late pregnancy, 2) the presence of high levels of circulating prolactin and mCS are apparently not necessary for continued secretion of progesterone from the CL during late pregnancy, 3) the fetoplacental unit may be the source of the luteotropic stimulus of late pregnancy since progesterone in the UOV decreases markedly in the absence of the fetoplacental unit or disruption of the unit brought about by fetectomy, and 4) regression of the CL following cesarean section in hypophysectomized monkeys is exceedingly slow when compared to the precipitous regression characteristic of the CL of the nonfertile menstrual cycle.

Animals↗

PubMed1977

Chorionic gonadotropin, chorionic somatomammotropin, and prolactin in the uterine vein and peripheral plasma of pregnant rhesus monkeys.

Seven adult female rhesus monkeys were laparotomized at days 22, 42, and 157 of pregnancy and blood was collected from the uterine vein and peripheral circulation. Plasma samples were analyzed for monkey chorionic gonadotropin (mCG), monkey chorionic somatomammotropin (mCS), and prolactin by radioimmunoassay. Levels of mCG at day 22 of pregnancy were approximately 250 ng/ml; however, during the later stages of gestation mCG was either nondetectable or less than 0.7 ng/ml. There was no statistical difference in prolactin concentrations between days 22 and 42 of pregnancy, mean levels being between 176-424 ng/ml, but by day 157 prolactin levels of greater than 2,000 ng/ml were recorded. No statistical difference existed between peripheral and uterine vein concentrations of either mCG or prolactin at any of the stages of gestation examined. At day 22, mCS was not detectable; however, at day 42 of gestation mCS titers averaged 1.5 micrograms/ml and 2.3 micrograms/ml in the peripheral and uterine vein plasma, respectively. A statistically significant mCS increase occurred by day 157, levels in the periphery and uterine vein averaging 11.0 micrograms/ml and 16.3 micrograms/ml, respectively. Uterine vein titers of mCS were significantly higher than peripheral titers at both days 42 and 157. Thus, the highest levels of mCG were present during early pregnancy, whereas the highest levels of mCS and prolactin were present during late pregnancy.

Animals↗

PubMed1975