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Biomedical subjects

S Batra

Publications and source records attributed to S Batra.

At least 181 records · Page 10Linked to original sources
PubMed1984

Effects of estradiol on norepinephrine-induced contraction, alpha adrenoceptor number and norepinephrine content in the female rabbit urethra.

Several studies have revealed that estrogen treatment increases the reactivity to catecholamines of various tissues. In the present study it was found that estrogen treatment caused an increased sensitivity to norepinephrine (NE) of the isolated female rabbit urethra. There was a 3-fold shift to the left of the concentration-response curve for longitudinal tension in perfused urethras and for tension in urethral ring preparations. Possible mechanisms for this increase in sensitivity were investigated by studying radioligand binding to the alpha adrenoceptors and by measuring the NE content of the urethras. Using [3H]dihydro-alpha-ergocryptine as a marker for alpha adrenoceptors, a more than 2-fold increase in the receptor number was found after estrogen treatment. This is suggested to be attributable to a selective increase in the number of alpha-2 adrenoceptors. No significant change was found in the affinity of [3H]dihydro-alpha-ergocryptine to the receptor. The total NE content in the urethra was not changed by estrogen treatment. However, if calculated per milligram of wet weight, the NE content was reduced to half in estrogen treated animals. It is suggested that in the rabbit urethra the estrogen-induced increased sensitivity to the contractant effects of NE, at least in part, is attributable to an increase in the number of postjunctional alpha-2 adrenoceptors.

Animals↗
PubMed1983

Bioluminescence assay of calcium with a liquid scintillation counter.

The luminescence produced by Ca aequorin reaction in dilute solutions decays exponentially over a relatively prolonged period of time. The concentration of total Ca and of free Ca in Ca-EGTA buffers could be determined by measuring the decay of luminescence in a liquid scintillation counter. The method is also suitable for determining total Ca concentration in small tissue samples.

Aequorin↗
PubMed1983

Effect of estrogen treatment on calcium uptake by the rat uterine smooth muscle.

The effect of estrogenization on cellular 45Ca uptake by the isolated uterine strips was studied. Whereas estrogenization 1 h before sacrifice of ovariectomized rats caused no significant change in Ca uptake by the isolated uteri, exposure to estrogen 24 h before sacrifice resulted in a significant increase in uptake. Following continuous exposure for 72 h to estrogen, the uptake of Ca was increasd by more than two-fold. Increased Ca uptake following estrogenization may largely account for the increased contractile responses of the uterine smooth muscle particularly those induced by potassium depolarization.

Animals↗
PubMed1983

The role of estradiol and progesterone in the regulation of myometrial activity for the onset of labor.

The concentrations of estradiol (E2) and progesterone (P) were measured in peripheral plasma and myometrium from women in the 35th to 42nd week of pregnancy. On the basis of the subjective symptoms and objective signs of labor, judged by tocography and cervical status, the women were divided into two groups, one in labor and the other not. There were no significant inter-group differences in the concentrations of E2 or P in either plasma or the myometrium. The plasma P/E2 ratio, however, differed significantly, being lower in the women in labor. A similar tendency was found in the P/E2 ratio in the myometrium but due to a wide variation, the inter-group difference did not attain statistical significance. The results suggest that a lower P/E2 ratio at term would facilitate the action of an, as yet unknown, physiological stimulus to the onset of labor.

Adult↗
PubMed1982

Some aspects of calcium uptake by human myometrial mitochondria and microsomes relevant to relaxation.

Calcium uptake by mitochondria and microsomes isolated from the human myometrium was studied at physiological Ca++ concentrations. The initial rates as well as the maximum velocity of Ca uptake by mitochondria were 10-20 times higher than those by microsomes. The Ca++ concentration for half-maximal transport in the mitochondria and microsomes was about 1 microM and 0.5 microM, respectively. The Ca uptake capacity of mitochondria measured after 20 min of uptake (1 microM Ca++ in the medium) was 10-30 times higher than that of microsomes. The capacity but not the initial rates of Ca uptake by microsomes was increased in the presence of 5 mM oxalate. These were only minor differences in the Ca uptake kinetics of subcellular fraction isolated from the pregnant and non-pregnant myometria. The results of this study reinforce the argument for the domineering role of mitochondria in the relaxation of the human myometrium.

Calcium↗
PubMed1982

Uptake and energy-dependent extrusion of calcium in the rat uterus.

The ability of lanthanum (La) to displace extracellular calcium or/and block calcium efflux from smooth muscle cells of the rat uterus was examined. Presence of 10 mM La in the medium used for tissue wash following 45Ca uptake (La method) increased 45Ca efflux particularly in the early phase (60 min) indicating displacement of extracellular calcium. Lowering of temperature from 37 degrees C to 2 degrees C of the La wash resulted in about three-fold increase in 45Ca retention by the tissue. Depolarization of tissue induced by high KCl during La wash at 37 degrees C had no effect on the retention of 45Ca. However, depolarization during 45Ca uptake significantly increased 45Ca uptake by the tissue which was counteracted by the presence of Nifedipine in the medium. The inhibition of tissue metabolic activity by FCCP had different effects on 45Ca retention depending on whether the tissues were washed at 37 degrees C or 2 degrees C. When active 45Ca extrusion during tissue washing was blocked (2 degrees C), 45Ca content of the tissues exposed to FCCP was reduced by about 35%. When tissues were allowed to actively pump out 45Ca (37 degrees C), 45Ca content of FCCP exposed tissues was increased by about 50%. It is concluded that about two thirds of the Ca extruded by the tissue is resistant to La blockage, and is dependent on the energy provided by tissue metabolic activity. During the use of the standard La method for measuring cellular calcium in the uterus, there is an underestimation due to unblocked 45Ca loss.

Animals↗
PubMed1981

Estrogen receptors in the human female lower uninary tract.

Cytosolic and nuclear fractions prepared from the urethra, urinary bladder, and trigonum of the bladder obtained at urethrocystectomy from four female patients were analyzed for the presence of estrogen receptors. High-affinity estradiol receptors (KD 0.7 x 10(-9)M) could be detected in both cytosolic and nuclear fractions of the urethra from all four patients. Estradiol receptors could be detected in only the nuclear fractions of the urinary bladder in two of the four preparations. In the trigonum, cytosolic and nuclear receptors could be measured in one and three preparations, respectively. The receptor concentrations in both trigonum and the bladder were lower than those in the urethra. By providing experimental evidence for the presence of estradiol receptors in the lower uninary tract, the present data advance the case for estradiol therapy in incontinent patients.

Adult↗
PubMed1981

Uptake in vivo of 45Ca in male accessory sex organs of the rat: effect of estramustine phosphate and diethylstilbestrol diphosphate.

The radioactivity following a single i.v. injection of 45Ca into male rats was found to be significantly higher in seminal vesicles, dorsolateral prostate, coagulating glands and ventral prostate than in muscle. The acute effect of a single dose given intraperitoneally of estramustine phosphate (Estracyt) and diethylstilbestrol diphosphate (Honvan) were examined on 45Ca uptake. Generally, the 45Ca concentration in the accessory sex organs with the exception of the dorsolateral prostate increased after administration of estramustine phosphate. Diethylstilbestrol phosphate treatment also significantly increased 45Ca uptake in the ventral prostate when measured on the basis of tissue wet weight but not on the basis of protein. The implications of these findings are discussed in relation to the therapeutic action of Estracyt in prostatic carcinoma.

Absorption↗
PubMed1981

Comparison of plasma and myometrial tissue concentrations of estradiol-17 beta and progesterone in nonpregnant women.

Plasma and myometrial tissue concentrations of estradiol (E2) and progesterone (P) were measured by radioimmunoassay techniques in samples obtained from women with regular menstrual cycles and from women in pre- or postmenopausal age. In women with regular cycles, the tissue concentration of E2 ranged from 0.13 to 1.06 ng/g wet weight, with significantly higher levels around ovulation than in follicular or luteal phases of the cycle. The tissue concentration of P ranged from 2.06 to 14.85 ng/g wet weight with significantly higher level in luteal phase than in follicular phase. The tissue/plasma ratio of E2 ranged from 1.45 to 20.36 with very high values in early follicular phase and the lowest in mid-luteal phase. The ratio for P ranged from 0.54 to 23.7 and was significantly lower in the luteal phase than in other phases of the cycle. One woman in premenopausal age with an ovarian cyst was the only case with a tissue/plasma ratio of E2 Less Than 1, since her plasma E2 levels were exceptionally high. In postmenopausal women, the tissue concentration of E2 was not significantly lower than in menstruating women in follicular phase, and the tissue concentration of P was not significantly lower than in fertile women in any of the phases. Neither in these women nor in menstruating women was there a close correlation between tissue and plasma levels. The present data indicate that the myometrial uptake capacity for ovarian steroids may be saturated, and also that a certain amount of these steroids is bound to tissue even if plasma levels are low.

Adult↗
PubMed1981

Local placental influence on the uterine concentration of oestradiol-17 beta and progesterone in the pregnant guinea-pig.

Oestradiol-17 beta (Oe2) and progesterone (P) concentration in the various regions of the uterus, and in ovaries with or without corpora lutea, were determined in the unilaterally pregnant guinea-pig at mid-term and full-term of pregnancy. The concentrations of both Oe2 and P were highest in the non-pregnant horn, and lowest in the perifoetal and juxtaplacental tissue in mid-term and term pregnancies, respectively. The Oe2 concentration in corpus luteum bearing ovaries was much lower than in those without corpora lutea, whereas the P concentration was higher. Ovariectomy performed at term resulted in a decrease of about 40% in plasma P concentration and no significant change in Oe2 concentration. This suggests that there is at least some contribution of P by the ovary even at term of pregnancy. The present data also provide strong evidence for the lack of local placental influence on the concentration of Oe2 and P in the uterus.

Animals↗
PubMed1980

Female sex steroid concentrations in the ampullary and isthmic regions of the human fallopian tube and their relationship to plasma concentrations during the menstrual cycle.

The concentrations of estradiol-17 beta (E2) and progesterone (P) were measured in the ampullary and isthmic portions of the fallopian tube of nonpregnant menstruating women and the cyclic fluctuations were related to the concentrations of these hormones in plasma. The steroid concentrations were determined by radioimmunoassays. There was no significant difference in the isthmic and ampullary concentrations of either steroid in any of the menstrual phases. The mean value for E2 was highest in the ovulatory phase and for P during the luteal phase. The tissue (per gm)/plasma (per ml) ratio for the steroid concentrations was above unity in all measurements. The ratio for E2 was highest (isthmus:12, ampulla:8) in the follicular phase and for P (isthmus:26, ampulla:18) during ovulation. Since these highest ratios were attained when plasma steroid concentrations were relatively low they were interpreted as reflections of a maximal receptor contribution.

Adult↗
PubMed1979

Are there cyclic variations in estradiol secretion in the non-pregnant rabbit?

Plasma estradiol-17 beta (E2) concentration was measured in 5 adult non-pregnant rabbits each in 3 different seasons (January, April and September). Blood samples were taken from each rabbit every other day. There was a considerable variation in plasma E2 levels from one sampling day to another, irrespective of the season. The pattern of variation in E2 levels in individual rabbits tended to be cyclic and this cycle was roughly of the order of 8 days. There was no correlation between changes in E2 levels and those in the vaginal appearance.

Animals↗