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41.
Daily LH-RH administration induced a dose related increase in fetal resorption in rats following hypophysectomy on Day 11 or Day 12 of pregnancy. Ovarian and adrenal weights, as well as serum progesterone levels, were significantly decreased by Day 18. Serum progesterone was also significantly lower than control in those animals that remained pregnant after receiving LH-RH post-hypophysectomy. These observations suggest that LH-RH exerts an anti-pregnancy effect via a placental:ovarian axis in this species. 相似文献
42.
The response to membrane surface charge of the glycerol headgroup of dimyristoyl-phosphatidylglycerol (DMPG) was investigated via deuterium and phosphorus-31 nuclear magnetic resonance spectroscopy. The membrane surface charge was manipulated by adding various amounts of neutral dimyristoylphosphatidylcholine (DMPC) and/or positively charged didodecyldimethylammonium bromide (DDAB) to the negatively charged DMPG, selectively deuterated at the alpha and beta segments of its glycerol headgroup. The deuterium and phosphorus-31 nuclear magnetic resonance spectra were all characteristic of random dispersions of liquid-crystalline lipids in a bilayer configuration. Differential scanning calorimetry showed that all mixtures investigated exhibited gel to liquid-crystalline phase transitions below 35 degrees C. Measurements of the deuterium quadrupole splitting and of the phosphorus-31 chemical shift anisotropy lead to the following observations. (1) Dilution of the negative surface charge density by the addition of DMPC had little effect on the quadrupole splitting from either alpha- or beta-deuterated DMPG. (2) Direct cancellation of the negative surface charge density by addition of DDAB led to a progressive decrease in the quadrupole splitting measured from alpha-deuterated DMPG, while the quadrupole splitting measured from beta-deuterated DMPG increased. For alpha-deuterated DMPG addition of 0.3 mole fraction of DDAB resulted in the appearance of two distinct quadrupole splittings. No such effect was observed for beta-deuterated DMPG. 相似文献
43.
G S Spencer A A Macdonald S S Carlyle L G Moore 《Reproduction, nutrition, development》1991,31(5):585-590
Twenty-six pig fetuses (at 94 days gestational age) were fitted with carotid artery catheters. Eight fetuses were given 1,500 ng of IGF-1 (in 100 microliters) directly into lateral cerebral ventricle; 7 further fetuses received the IGF-1 together with 150 microliters of a potent specific anti-somatostatin serum into a ventricle, 5 other fetuses received the anti-somatostatin serum alone while 6 controls received normal sheep serum. Administration of IGF-1 caused a rapid decrease in circulating growth hormone (pGH) levels but there was no significant change in plasma levels of somatostatin immediately following the IGF-1 administration, suggesting that the decrease in pGH was not mediated by somatostatin secretion. Further evidence that somatostatin was not involved in this effect was provided by the lack of effect of concurrent antisomatostatin serum on the IGF-1-induced decrease in pGH. Thus the high circulating levels of GH in the fetus may result from a lack of feedback of IGF-1, but not through the somatostatin-pituitary axis. 相似文献
44.
Ten men with uncomplicated essential hypertension (mean standing blood pressure 165/109 mm Hg) and 10 normal controls matched for age and weight were studied for the hypotensive potential of moderate exercise. Tests were conducted on a treadmill set to induce a steady heart rate of 120 beats/min and performed over five 10-minute periods separated by three minutes'' rest and finishing with 30 minutes'' sitting quietly in a chair.During exercise the mean systolic pressures were identical in the hypertensive patients and controls (175±SEM 5 mm Hg), the controls therefore sustaining an appreciably greater increase in pressure. During the 30-minute rest period after the tests both the control and hypertensive groups showed a significant and sustained fall in absolute systolic pressures as compared with pre-exercise values (p <0·001), the mean percentage reductions being 22% and 25% respectively.If a fall in blood pressure after exercise is maintained for four to 10 hours, then a “good walk” twice a day might be reasonable treatment for mild hypertension. Studies are continuing to determine the amount of exercise needed and the duration for which the reduction in blood pressure is maintained. 相似文献
45.
D A Henry I A Macdonald G Kitchingman G D Bell M J Langman 《BMJ (Clinical research ed.)》1980,281(6243):775
Paired studies of hepatic microsomal function were conducted in eight subjects during treatment with two histamine H2 antagonists, cimetidine and ranitidine. Cimetidine but not ranitidine inhibited the metabolism of antipyrine (phenazone) and demethylation of aminopyrine (aminophenazone) as measured by breath 14CO2 production after intravenous injection of 14C-aminopyrine. These results suggest that the metabolic inhibitory actions on the liver may be separated from H2 antagonist effects, and that ranitidine has an advantage over cimetidine by not inhibiting microsomal drug oxidative function. 相似文献
46.
P G Casola F Chan P M Macdonald S Ryan W C McMurray F Possmayer 《Biochemical and biophysical research communications》1980,96(3):1209-1215
The enzymes responsible for the biosynthesis of phosphatidylglycerol, CTP:phosphatidate cytidylyltransferase, CDP-diacylglycerol: glycerophosphate phosphatidyltransferase and phosphatidylglycerophosphate phosphatase demonstrated a coordinate increase in activity in fetal rat lung at term when the demand for pulmonary surfactant increases. The activity of CTP:cholinephosphate cytidylyltransferase, the enzyme responsible for CDP-choline production also increased in the perinatal period. The activity of cholinephosphate cytidylyltransferase in fetal and neonatal cytosol was stimulated by the addition of phosphatidylglycerol but no effect was noted with cytosol from adult lung. These results are consistent with the suggestion that the activity of cholinephosphate cytidylyltransferase, a potential rate-determining enzyme in pulmonary phosphatidylcholine synthesis, may be regulated in the perinatal period both through an activation by phosphatidylglycerol and by an increase in total enzyme units. 相似文献
47.
The results of bilateral pedal lymphography in 83 patients with adenocarcinoma of the prostate gland are presented. The patients were divided into two groups: 45 new cases and 38 late or old cases presenting several years after the onset of the disease. Altogether 25 of the new patients and 29 of the late patients had lymphographic evidence of lymph node metastases. The lymphogram results in relation to local tumour size, histological grade, the presence of skeletal metastases, and acid phosphatase levels are discussed. Of the new patients with T1 and T2 tumors--that is, those still localized within the prostatic capsule--41% had positive lymphograms. The inaccuracy of acid phosphatase estimations in detecting early extraprostatic spread is shown and compared with the greater accuracy of lymphography. Lymphography should be used as an initial investigation in all cases where aggressive therapy is being considered, and the importance of regular follow-up radiographs is emphasized. 相似文献
48.
Macdonald Jed I. Drysdale Russell N. Witt Roman Cságoly Zsófia Marteinsdóttir Guðrún 《Reviews in Fish Biology and Fisheries》2020,30(1):173-202
Reviews in Fish Biology and Fisheries - For marine fishes of commercial interest, defining how individuals vary in certain attributes, through ontogeny, and across space and time, can help expose... 相似文献
49.
50.
S J Standing M J Brindle A P Macdonald R W Lacey 《BMJ (Clinical research ed.)》1981,283(6293):705-707
Over a two-year period, 3479 pregnant women in the Kings'' Lynn Health District were screened for neural tube defects by estimation of maternal serum alpha-fetoprotein. Most pregnancies were scanned by sonar for fetal maturity. Eight women had fetuses with open neural tube defects; four with anencephaly were associated with very high alpha-fetoprotein values. Of the four with open neural tube defects without anencephaly, only one was detected by screening and confirmed after amniocentesis. One other had a raised serum alpha-fetoprotein but a normal amniotic fluid value. The other two affected fetuses were missed. This disappointing outcome was attributed to the poor predictive value of alpha-fetoprotein in detecting open neural tube defects (anencephaly apart) rather than to errors in its estimation or in assessment of fetal maturity by sonar scan. We question the validity of screening, particularly in areas of intermediate or low incidence. 相似文献