Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: DrugBank:APRD00627 (MAP)
 15,705 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The specific aspects of the respiratory cycle during mechanical ventilation that allow for optimum gas exchange are still controversial. To further clarify the relationship of inspiratory:expiratory ratio and positive end expiratory pressure to optimum ventilation and oxygenation, five premature lambs with severe hyaline membrane disease were ventilated with volume-present infant ventilators at I:E ratios of 1:4 and 1:1 and PEEP levels of 0, 5, and 10 cm H2O. For each I:E ratio/PEEP combination, pH, Pao2, PaCO2, PAO2, PACO2, peak inspiratory pressure, mean inspiratory pressure, and mean airway pressure were measured and compared. Optimum ventilation and oxygenation were related to MAP, but not to I:E ratio, PIP, or MIP. As MAP increased from 6 to 14 cm H2O, progressive improvement in Pao2, PaCO2 (A-a) DO2 and (a-A) DCO2 was evident. Above 14 cm H2O, there was progressive deterioration in these measurements. There was also a direct relationship between MAP and mean pleural pressure. These results indicate that during mechanical ventilation there is an optimum MAP at which gas exchange is best. Since MAP changes with any change in PIP, PEEP, or I:E ratio, it provides a useful composite measure of all pressures transmitted to the airways by the ventilator.
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PMID:The effect of independent variations in inspiratory-expiratory ratio and end expiratory pressure during mechanical ventilation in hyaline membrane disease: the significance of mean airway pressure. 33 78

Roles of ovarian progesterone secretion and maternal nutrition in fetal development were investigated in a species that normally experiences considerable embryonic and fetal mortality. Pregnancies were maintained in 81% of Yorkshire pigs during prolonged starvation (e.g., 40 days; 0 kcal/day, water only) in either the middle third (days 30-70) or last third (days 70-110) of gestation compared with 100% in full-fed controls (7,028 kcal/day). In spite of severe maternal deprivation, fetal survival rates averaged 65% in starved dams and 63% in controls; mean number of living fetuses was 9.9 in starved and 9.6 in control dams. Fetal growth was reduced by maternal starvation during the middle third, but not the last third of pregnancy. Placental insufficiency was the primary cause of reduced fetal growth and resulted in abortion in a few of the dams. Progesterone in peripheral serum of dams starved either during middle or late pregnancy was maintained at levels similar (P greater than 0.05) to those in controls. Abortion occurred in starved dams only when serum progesterone concentrations dropped to less than 10 ng/ml within 3 days before loss of conceptuses.
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PMID:Progesterone secretion and fetal development during prolonged starvation in the pig. 43 95

The relationships of maternal nutrition and progesterone secretion to prenatal fetal loss and neonatal survival and growth were investigated in domesticated pigs that normally experience 40% fetal loss. Yorkshire pigs were subjected to prolonged starvation (40 days; 0 kcal/day; water only) in either the middle third or last third of pregnancy and then gradually realimented to a full diet and allowed to advance to parturition; controls received a full diet (7,028 kcal/day) throughout gestation. Pregnancies were maintained in 74% of the pigs starved during either middle or late gestation compared to 100% in controls. In dams starved from days 30--70, progesterone levels remained similar to controls, but were maintained at lower levels during realimentation between days 72 and 99. Progesterone levels in dams starved days 50--90 and controls were similar from days 50 to 130. At parturition, litter size in starved dams (9.4) was similar to full-diet controls (8.0) although birth weight and neonatal growth of piglets were reduced markedly from dams starved in middle or late pregnancy. These results indicate that severe maternal nutrient deprivation during the middle or last third of gestation has little effect on ovarian progesterone secretion and is not a major limitation to fetal survival in this litter-bearing species. Maternal nutrient deprivation imposes a significant detrimental effect, however, on birth weight and neonatal growth to 80 days of age.
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PMID:Maternal starvation and progesterone secretion, litter size, and growth in the pig. 47 53

The menstrual flow of five dysmenorrhoeic women was collected, four cycles with and two cycles without local intrauterine administration of progesterone (Progestasert). The menstrual flow of three eumenorrhoeic women served as control. Menstrual blood was collected by tampons stored in butyl-alcohol saturated with water. Prostaglandin F2alpha (PGF2alpha) was measured after purification and extraction by radioimmunoassay. The PGF2alpha production rate and concentration per ml of menstrual blood from dysmenorrhoeic women differed significantly from those of eumenorrhoeic women. In the treated cycles the PGF2alpha levels were significantly decreased (2 alpha less than or equal to 0,01), corresponding to eumenorrhoeic levels. These values were in accordance with the clinical results and indicate that uterine PG-synthesis is under progesterone control.
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PMID:[The effect of progesterone uterine therapeutic system on dysmenorrhoea: prostaglandin F2alpha levels in menstrual blood (author's transl)]. 66 82

The effect of lowering the pressure of oxygen from 80 to 34 mm Hg was examined in anesthetized dogs that were undergoing a water diuresis. This degree of hypoxia was associated with an antidiuresis as urine osmolality (Uosm) increased from 107 to 316 mosmol/kg H(2)O (P < 0.001) and plasma arginine vasopressin increased from 0.06 to 7.5 muU/ml, (P < 0.05). However, hypoxia was not associated with significant changes in cardiac output (CO, from 4.2 to 4.7 liters/ min), mean arterial pressure (MAP, from 143 to 149 mm Hg), glomerular filtration rate (GFR, from 46 to 42 ml/min), solute excretion rate (SV, from 302 to 297 mosmol/min), or filtration fraction (from 0.26 to 0.27, NS). Hypoxia was associated with an increase in renal vascular resistance (from 0.49 to 0.58 mm Hg/ml per min, P < 0.01). The magnitude of hypoxia-induced antidiuresis was the same in innervated kidneys and denervated kidneys. To further examine the role of vasopressin in this antidiuresis, hypoxia was induced in hypophysectomized animals. The effect of hypoxia on CO, MAP, GFR, SV, and renal blood flow in hypophysectomized animals was the same as in intact animals. In contrast to intact animals, however, hypoxia did not induce a significant antidiuresis in hypophysectomized animals (Uosm from 72 to 82 mosmol/kg H(2)O). To delineate the afferent pathway for hypoxia-stimulated vasopressin release, hypoxia was induced in dogs with either chemo- or baroreceptor denervation. The effect of hypoxia on CO, MAP, GFR, SV, and renal blood flow in the denervated animals was the same as in nondenervated animals. Hypoxia resulted in an antidiuresis in chemoreceptor (Uosm from 113 to 357 mosmol/kg H(2)O, P < 0.001) but not in baroreceptor (Uosm from 116 to 138 mosmol/kg H(2)O, NS) denervated animals. To determine if hypoxia alters renal response to vasopressin, exogenous vasopressin was administered to normoxic and hypoxic groups of dogs. The antidiuretic effect of vasopressin was no different in these two groups. These results demonstrate that hypoxia induces an antidiuresis which is independent of alterations in CO, MAP, SV, filtration fraction, renal nerves, or renal response to vasopressin and occurs through baroreceptor-mediated vasopressin release. The nature of the baroreceptor stimulation remains to be elucidated.
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PMID:Mechanism of effect of hypoxia on renal water excretion. 70 76

1. The effect of progesterone on renal haemodynamics and intrarenal sodium handing was evaluated in thirteen normal men on a constant diet. Clearances were measured during maximal water diuresis and again 4-7 days later, this time 3 h after progesterone was given intramuscularly. Seven additional studies were performed 3 days after progesterone administration. Another four tests were performed on volunteers who had manifested renal 'escape' from the sodium-retaining effect of deoxycorticosterone acetate. 2. In acute progesterone studies glomerular filtration rate was unchanged, whereas effective renal plasma flow increased, so that filtration fraction decreased significantly. A similar in crease in urinary sodium occurred whether subjects received a low or high sodium diet. Indices which related to the distal delivery of filtrate (fractional urine flow and the sum of fractional free water and sodium clearances) increased significantly in both groups. The progesterone-induced increase in sodium excretion was not related to changes in plasma renin activity, renin substrate or urinary aldosterone. After 3 days of progesterone, the increase of sodium excretion was less than in the acute studies and urinary aldosterone increased tow- to four-fold. Progesterone failed to produce an acute increse in urinary sodium in subjects hyperexpanded by administration of exogenous mineralocorticoids. 3. Results suggest that the acute natriuretic action of progesterone is in part independent of aldosterone inhibition and that progesterone may inhibit sodium reabsorption at proximal as well as distal sites in the nephron.
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PMID:Effect of progesterone on renal sodium handling in man: relation to aldosterone excretion and plasma renin activity. 114 5

A new assay for the measurement of steroid 17alpha-hydroxylase activity in beef adrenals is described. This method is based on the biochemical mechanism of the enzymic reaction, i.e. the direct and stereospecific substitution of the proton located on the hydroxylated position. Progesterone or pregnenolone specifically labelled on the 17 position are solubilized in the incubation mixture with the help of Tween 80 and incubated under optimal conditions. The tritium enzymically released from the substrate is found in the medium as a molecule of water which is then distilled under reduced pressure and counted by liquid scintillation. The results obtained with this new method are comparable with those obtained with a conventional method using a 14C-labelled substrate.
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PMID:New assay for pregnenolone and progesterone 17alpha- hydroxylase based on the specific substitution of a tritium situated on carbon 17. 124 68

The in vivo and in vitro metabolism of 3H-testosterone by rat epididymis and the changes in epididymal weight have been studied after castration and treatment with anti-androgens. The utilization of 3H-testosterone was greatly reduced after castration as was the formation of 5alpha-reduced 17 beta-hydroxy metabolites. The formation of the 17 -keto metabolites was unaffected. Castration had no effect on the ratio between water and ether soluble radioactivity. Administration of testosterone propionate, necessary for giving normal stimulated prostate weight (150 mug/day), restored the metabolism of testosterone to approximately normal values. Estradiol benzoate and progesterone inhibited metabolism of testosterone in vitro and greatly reduced the formation of DHT (17 beta-hydroxy-5alpha-androstan-3-one) and 3 alpha-diol(5 alpha-androstane-3 alpha-17 beta-diol) by experiments both in vivo and in vitro. No effect of cyproterone acetate could be demonstrated on either the in vitro or in vivo metabolism of testosterone. Castration for 14 days reduced the epididymal weight to about 30% of that found in intact animals. Administration of testosterone propionate restored the epididymal weight to about 80% of normal. Estradiol benzoate and cyproterone acetate given to intact rats led to a decrease in the epididymal weight. Progesterone had no such effect. In 14 days castrated rats receiving testosterone propionate all three anti-androgens reduced the weight of the epididymis. In conclusion, our results show that the metabolic conversion of testosterone in epididymis to DHT and 3 alpha-diol is dramatically dependent on the hormonal status of the animal; castration or treatment with anti-androgens causes a reduced formation of the "active" androgens whilst testosterone replacement treatment restores the metabolism of testosterone to normal.
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PMID:Androgen metabolism by rat epididymis. 3. Effect of castration and anti-androgens. 126 92

Propagation problems in buffaloes are often not easily recognizable, particularly lacking are studies on the repeat breeding syndrome. In the present study repeat breeder buffaloes were inseminated 3 or more times within the same lactation period. The incidence of typical repeat breeders was 8.33% in the lactation herd. These animals had a longer lactation period and a higher number of services per conception than normal buffaloes. The correlation coefficients were significant between the number of services per conception and each of weight at birth and weight at first service. Repeat breeders significantly (P < 0.05) surpassed normal buffaloes in creatinine values and had contrary values in the serum albumin concentration, glucose, inorganic phosphate, and zinc. Progesterone in urine (efficacious progesterone) was significantly lower on the 10th day post estrus, whereas the non-efficacious progesterone was significantly higher in repeat breeders. Supplying the repeat breeders with sodium phosphate for 1 month 40 g/head/day in the diet and 500 ppm zinc acetate in the drinking water improved the conception rate by 80%.
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PMID:Typical repeat breeding and its improvement in buffaloes. 129 3

A new technique is outlined for the characterization and quantification of M2 muscarinic binding sites (receptors) in micropunches (1 mm diam.), cut from slices (350 microns), of fresh cardiac tissue using the hydrophilic antagonist [3H]N-methyl scopolamine. The use of this water-soluble ligand allows us to label, and quantify, M2 receptors on the cell surface of intact cells contained within the micropunch. We believe that cardiac micropunches offer a simple but powerful approach to the investigation of membrane receptor regulation in tissue that largely retains the in vivo cytoarchitecture. Specific binding is reversible, stereospecific, saturable, of high affinity, and has the drug specificity typical of an M2 muscarinic receptor. In rat left ventricle, Bmax was 151.2 +/- 10.3 fmol/mg protein while KD was 1.0 +/- 0.1 nM. Nonspecific binding of the ligand was very low, varying from 2.8% (at 0.27 nM) to 7.7% (at 3.58 nM). This micropunch assay was used to determine that progesterone can compete with the muscarinic ligand for the M2 receptor in vitro (IC50 = 50 x 10(-6) M). The steroids estradiol and testosterone, as well as ouabain, were without effect. Progesterone inhibited [3H]N-methyl scopolamine binding competitively (KD reduced from 1.9 to 4.3 nM) without affecting the rate of association of the ligand. However, progesterone induced a rapid dissociation of the ligand from its receptor. We conclude that the micropunch assay described here is suitable for the continued study of sex hormone effects on cardiac function.
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PMID:M2 muscarinic ([3H]N-methyl scopolamine) binding in micropunches of rat ventricular myocardium: characterization and modification by progesterone. 145 Oct 31


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