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Query: UMLS:C0432222 (
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47,337
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
1. Indomethacin inhibits prostaglandin synthesis and interferes with renin release; these effects were studied in rabbit renovascular hypertension. 2. Ten intravenous injections (3 mg day-1 kg-1 after two initial doses of 9 mg/kg) of indomethacin were given daily to ten normal rabbits, ten rabbits with two-kidney Goldblatt hypertension (2KH), tension (1KH). Twelve appropriate control rabbits received diluent phosphate buffer without indomethacin. Plasma renin activity and plasma prostaglandin E2 were measured by radioimmunoassay. 3. In the normal group, indomethacin significantly decreased plasma prostaglandin E2 (1-15 to 0-2 ng/ml,
SEM
0-2; P less than 0-01) and plasma renin activity (20 to 3 ng h-1 ml-1,
SEM
1, P less than 0-01). Plasma creatinine increased slightly but the mean blood pressure was not significantly changed by indomethacin. 4. Six of ten rabbits with 2KH showed results similar to those in the normal rabbits. In four of ten rabbits in which development of 2KH was accompanied by increments in plasma renin activity (18 to 31-5 ng h-1 ml-1,
SEM
3 and 4 respectively; P less than 0-01) and plasma prostaglandin E2 (1-2 to 3-4 ng/ml,
SEM
0-2 and 0-4 respectively; P less than 0-05), treatment with indomethacin produced renal failure (plasma creatinine increasing to 7-6 mg/100 ml), oliguria, malignant hypertension (mean blood pressure, 168 mmHg,
SEM
7-7) and death within 5 days. 5. In 1KH, indomethacin decreased plasma renin activity and plasma prostaglandin E2, but caused increased mean blood pressure (102 to 121 mmHg,
SEM
4 and 6 respectively; P less than 0-01) and decreased renal function (plasma creatinine 0-9 +/- 0-04 to 3-5 +/- 1 mg/100 ml,
SEM
0-04 and 1 respectively; P less than 0-01). 6. Aggravation of hypertension was conditioned by pre-existing levels of renal function and, to a lesser extent, by plasma renin activities. 7. These results suggest that prostaglandins exert a protective effect on renal function in renovascular hypertension.
Clin Sci Mol Med Suppl 1976
Dec
PMID:Effects of indomethacin in rabbit renovascular hypertension. 107 20
1. Serum dopamine beta-hydroxylase activity was determined in normotensive control subjects and patients with labile or established essential hypertension. The enzyme activity was 25-9 +/- 1-9 (
SEM
) 29-6 +/- 2-5 and 25-1 +/- 1-9 micronmol min-1 1-1, for control, labile and established hypertensive subjects respectively. 2. Neither blood pressure nor serum dopamine beta-hydroxylase activity was changed in normotensive control subjects by administration of phentolamine; however, in patients with essential hypertension blood pressure was significantly decreased (P is less than 0-01) and serum dopamine beta-hydroxylase activity was slightly increased. With propranolol administration, blood pressure and the serum enzyme activity were not significantly changed in normotensive or hypertensive subjects. 3. Our results suggest that there is no correlation between serum dopamine beta-hydroxylase activity and blood pressure.
Clin Sci Mol Med Suppl 1976
Dec
PMID:Serum dopamine beta-hydroxylase activity in essential hypertension. 107 65
1. The National Blood Pressure Study (NBPS) is a single blind trial designed to test the efficacy of active drug treatment in reducing complications from mild hypertension (mean diastolic pressure = 95-109 mmHg). 2. Between 1973 and 1975, four centres screened about 104 000 subjects aged 30-69 years, yielding an estimated prevalence of hypertension (greater than or equal to 95 mmHg diastolic) of 16% and of moderate-to-severe hypertension (greater than of equal to 110 mmHg diastolic) of 1-3%. 3. Some 4000 subjects selected for untreated uncomplicated mild hypertension were randomized to either active treatment (cholorothiazide +alpha-methyldopa and/or a beta-adrenoreceptor antagonist as required) or to matching placebos. 4. At 1 year mean pressures had fallen significantly below entry pressures in both groups but in the active group the fall was greater by a margin of 14-4+/-1-3 (
SEM
) mmHg systolic and 7-1+/-0-7 mmHg diastolic. At 1 year 5% of subjects in the placebo group had been placed on active treatment on the ethical grounds that pressure had exceeded the mild hypertension limit. 5. Trial end-points (death, morbidity from stroke, hypertensive heart and renal disease, and ischaemic heart disease) number 106 (nine deaths) thus far, of which ischaemic heart disease accounts for 71% and stroke 19%. 6. The duration of trial may need to be extended beyond the original estimate of 5 years.
Clin Sci Mol Med Suppl 1976
Dec
PMID:Report on progress in the Australian National Blood Pressure Study (NBPS). 107 98
A variety of studies in man and animals demonstrate that testosterone (T) is aromatized to estradiol (E) in the hypothalamus and limbic system. These observations suggested the possibility that conversion to E is an absolute requirement for the biologic activity of T on the hypothalamic-pituitary axis. Since this hypothesis implies a common mechanism of action of these two steroids, the demonstration of divergent effects of T and E on luteinizing hormone (LH) secretion would exclude this possibility. To test this hypothesis, the actions of T and E on three separate aspects of LH release (mean LH, pulsatile LH secretion, and responsiveness to LH-releasing hormone [LH-RH]) were contrasted. T and E, infused at two times their respective production rates into normal men, reduced mean LH levels similarly during 6 h of steroid infusion and for 6 h thereafter. However, these steroids exerted different effects on pulsatile secretion. E reduced the amplitude of spontaneous LH pulse from pre- and postinfusion control levels of 75+/-14 and 68+/-5.6% (
SEM
) to 39+/-5.7%. In contrast, T increased pulse amplited to 96+/-14% and decreased pulse frequency from basal levels of 3.4+/-0.31 to 1.8+/-0.31 pulses/6h. The site of suppressive action was determined by administering 25 microgms of LH-RH to the same men during T and E infusions and during three additional control periods without steroid administration. LH-RH produced similar 170-190% increments in serum LH during the three control periods and during T infusion. In contrast, E markedly blunted (76+/-31%, p less than 0.005) the LH response to LH-RH. Under the conditions of acute steroid infusion at doses (utilized in these experiments) producing similar inhibition of mean LH, E but not T acted directly on the pituitary to diminish LH-RH responsiveness. As further support that androgens can act without conversion to estrogens, the effects of a nonaromatizable androgen, dihydrotestosterone (DHT), on mean LH levels were studied. DHT, infused at the same rate as T, suppressed mean LH to a similar but somewhat greater extent than T. Since T and E produced divergent effects on LH secretion and a nonaromatizable androgen, DHT, suppressed mean LH, aromatization is not a necessary prerequisite for the action of androgens on the hypothalamic-pituitary axis.
J Clin Invest 1975
Dec
PMID:Is aromatization of testosterone to estradiol required for inhibition of luteinizing hormone secretion in men? 110 59
Using an in vitro rabbit pancreas system, we studied the effect of monoamine oxidase (MAO) inhibitors on flucose-stimulated insulin secretion. We evaluated the effect of both brief (15 min) and prolonged (60 min) exposure of pancreas segments to non-hydrazine (harmine, alpha-methyltryptamine, tranylcypromine and pargyline) and hydrazine (phenelzine, nialamide, iproniazid) type MAO inhibitors. All of the hydrazine type MAO inhibitors potentiated glucose-stimulated insulin secretion. Of the non-hydrazine inhibitors, only harmine and alpha-methyltryptamine potentiated glucose-stimulated insulin secretion. Hydrazine, although not itself an MAO inhibitor, also potentiated insulin secretion. Sixty minutes of exposure to tranylcypromine or alpha-methyltryptamine caused a decrease in insulin secretion. These MAO inhibitors are primary amines and primary amines can inhibit insulin secretion. The dopamine (DA) or serotonin (5-HT) content of the B-cells was increased by incubating rabbit pancreas with L-3, 4-dihydroxyphenylalanine (L-Dopa) or 5-hydroxytryptophan (5-HTP) for forty-five minutes prior to stimulation with glucose. Non-hydrazine MAO inhibitors increased dopamine inhibition of insulin secretion and either did not alter, or decreased serotonin inhibition of insulin secretion. Rabbit pancreatic islets were isolated using the collagenase digestion technique. The MAO activity of islet homogenates was determined using 5-HT and DA as substrates. Rabbit islet MAO has only one-tenth the specific activity against 5-HT (35 +/- 8.7 mumumoles/mg/min, M +/-
SEM
) that it has against DA (357 +/- 62.3 mumumoles/mg/min). This suggests that one reason that MAT inhibitors do not increase serotonin inhibition of insulin secretion is because MAO is not the major pathway for 5-HT inactivation in rabbit pancreatic islets. These studies suggest that MAO inhibitors alter insulin secretion, by both decreasing B-cell monoamine degradation and by mechanisms that do not involve MAO inhibition.
Diabetologia 1975
Dec
PMID:Monoamine oxidase inhibitors: nature of their interaction with rabbit pancreatic islets to alter insluin secretion. 110 23
The ventilatory responses to isocapnic hypoxia and hypercapnia were studied in seven chronically tracheostomized dogs awake and during anesthesia with pentobarbital (30 mg/kg, iv), ketamine, or thiopental (10 and 15 mg/kg, respectively, followed by infusion). Isocapnic hypoxic ventilatory drive (HVD) was expressed as the parameter A such that the higher the A, the greater the hypoxic drive. HVD(A) was significantly reduced from 259 +/- 28 (mean +/-
SEM
) in awake dogs, to 96 +/- 14 after pentobarbital, 161 +/- 27 after thiopental, and 213 +/- 23 after ketamine. Hypercapnic ventilatory drive (HCVD) as measured by S (slope of the VE-PACO2 response curve) was significantly reduced from 1.3 +/- .32 in awake dogs to 0.4 +/- .13 after pentobarbital, 0.5 +/- .12 after thiopental, and 0.6 +/- .11 after ketamine. In addition, hypercapnia-induced augmentation of hypoxic drive was markedly diminished by the two barbiturates but was unaffected by ketamine. Therefore, ketamine at this dose level afforded greater protection during exposure to hypoxia than did barbiturates. (Key words: Ventilation, hypoxic response; Hypoxia, ventilation; Oxygen, ventilatory response; Carbon dioxide, ventilatory response; Anesthetics, intravenous, ketamine; Anesthetics, intravenous, thiopental; Hypnotics, barbiturates, pentobarbital.)
Anesthesiology 1975
Dec
PMID:Hypoxic ventilatory drive in dogs during thiopental, ketamine, or pentobarbital anesthesia. 119 May 38
Three urinary excretion tests of vitamin B12 absorption were done in 12 patients with classic pernicious anemia. The 24-hour urinary excretion of radioactivity was 2.1% +/- 0.7% (mean +/-
SEM
) of the ingested dose of cyanocobalamin-57 Co. When cyanocobalamin-57 Co was mixed with hog intrinsic factor in water, excretion increased to 15.6% +/- 1.6%. When cyanocobalamin-57 Co and intrinsic factor were given in two separate capsules, which is now a frequent practice, excretion was 9.5% +/- 2.2%. In 6 patients, use of the results obtained with capsules could have led to an incorrect diagnosis. When cyanocobalamin-57 Co and intrinsic factor are given in separate capsules, binding of radioactive vitamin to intrinsic factor may be incomplete due to inadequate mixing in the stomach or to binding of intrinsic factor to blocking antibody in the gastric juice. The classic technique in which intrinsic factor and cyanocobalamin-57 Co are mixed in water before administration should be used.
Ann Intern Med 1975
Dec
PMID:Spurious Schilling test results obtained with intrinsic factor enclosed in capsules. 120 May 29
To investigate the in vivo whole blood metabolic clearance rates and sites of metabolism of prostaglandins A1 and E1 in man, constant infusions of the tritiated compounds were administered to normal subjects and to patients undergoing cardiac catheterization. The whole blood metabolic clearance rate of [3H]prostaglandin A1 in eight men was 5,003 +/- 864 liters/day (SD) or 2,546 +/- 513 liters/day per m2 (SD). Nonradioactive prostaglandin A1 was similarly infused in two subjects, and the metabolic clearance rates were determined, utilizing a specific radioimmunoassay. The clearance rates with this method correlated closely with those determined by the isotope infusions. Extraction studies of prostaglandin A1 showed that pulmonary, splanchnic, renal, and extremity perfusions resulted in 8.1 +/- 4.1, 56.1 +/- 10.1, 50.3 +/- 3.4, and 34.4 +/- 5.9% (
SEM
) removal, respectively. With [3H]=prostaglandin E1, the whole blood metabolic clearance rate was determined from the pulmonary artery concentration in three patients and averaged 4,832 +/- 1,518 liters/day (SD) or 2,686 +/- 654 liters/day per m2 (SD). Pulmonary extraction was 67.8 +/- 6.8% (
SEM
) and extremity removal averaged 6.6 +/- 4.9% (
SEM
). These results indicate that A prostaglandins are metabolized by several organs, such as the liver and kidney, and possibly by intravascular pathways as well. In man, the E prostaglandins are primarily metabolized by the lung, but extraction is not complete and approximately one-third may escape lung metabolism. Thus, these findings suggest that both E and A prostaglandins in the venous circulation may reach the systemic circulation in man.
J Clin Invest 1975
Dec
PMID:Metabolism of prostaglandins A1 and E1 in man. 120 78
1. Systolic blood pressure was measured by a Doppler ultrasound technique in twenty normal babies on 6 successive days after the day of delivery. In three babies blood pressure was recorded every 15 min for 24 h. 2. Systolic blood pressure during the first 6 days of life was 95 (
SEM
= 2) mmHg. 3. Systolic blood pressure increased on average by 2 mmHg/day, but increased most between the second and third days of life. 4. Systolic blood pressure was 11 mmHg higher when awake than when the babies were asleep. 5. There was marked within-baby variation in the systolic blood pressure of neonates, which could not be accounted for by age or recognizable changes in level in consciousness.
Clin Sci Mol Med 1975
Dec
PMID:Systolic blood pressure variation during the first 6 days of life. 120 86
Somatostatin, a growth hormone inhibiting factor (GHIF), was infused into 8 patients with primary hypothyroidism at a dosage of 1000 mug for 105 min. GHIF caused a suppression of TSH levels from 42.6 to 76.9% of preinfusion levels with a mean nadir of 65.0 +/- 4.0%;(mean +/-
SEM
).
J Clin Endocrinol Metab 1975
Dec
PMID:The effect of somatostatin on TSH levels in patients with primary hypothyroidism. 120 95
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