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The following conditions in patients with alcoholic cardiac involvement predispose to recurrences of atrial fibrillation: atrial dilatation, shortening of refractory period, slowing of atrial conduction, increased vulnerability to extra stimuli, appearance of fragmented electrical activity i.e. late atrial potentials on high resolution ECG, autonomic influences on the heart, hypokalemia and hypomagnesemia.

128 patients with primary mitral prolapse and 72 healthy controls were examined using noninvasive methods. The analysis of the findings revealed predictors of electric myocardial unstability: reduced variability of cardiac rhythm, diastolic left ventricular dysfunction, late ventricular potentials and growing dispersion of the Q-T interval. Detection of mitral regurgitation correlates with development of ventricular arrhythmia.

The study of 46 patients suffering from dilated cardiomyopathy has shown that both ventricular tachycardias detected at 24-h ECG monitoring and late ventricular potentials are essential predictors of sudden arrhythmic death. These predictors depend neither on severity of left ventricular systolic and diastolic dysfunction nor on severity of cardiac decompensation.

When dialysed rat serum which contains a single, low molecular weight binder for vitamin B12, rat transcobalamin II (rat TC-II), was labelled in vitro with 57Co-vitamin B12 and then incubated at 30 degrees C (pH 7-5) with vesicles of highly purified plasma membranes separated from microsomal fractions of rat liver by density gradient centrifugation, the 57Co-vitamin B12-rat TC-II complex bound to high affinity sites on the vesicles via a specific (binding after correction for 'non-specific' binding in the presence of a large excess of the non-radioactive complex), saturable, and reversible interaction. The apparent affinity constant for the binding reaction was 5-5 X 10(9) M-1. Using the same incubation conditions, free vitamin B12 also bound to the vesicles of plasma membranes via a specific, saturable, but apparently irreversible interaction. Preincubation of the membranes with free vitamin B12 did not interfere with the subsequent binding of the vitamin B12-rat TC-II complex to the membranes; however, preincubation with the vitamin B12-rat TC-II complex did interfere, to some extent, with the subsequent binding of free vitamin B12. Dialysed rat serum, perhaps the free rat TC-II in the dialysed serum, also inhibited the binding of the vitamin B12-rat TC-II complex to the plasma membranes. The relationship of the binding sites identified in this report to the absorption of vitamin B12 by rat liver, and thus their physiological significance remains unknown until further work is done, perhaps using intact hepatocytes.

Hypercholesterolemic subjects in a metabolic ward were kept under uniform dietary conditions until constant levels of serum cholesterol were observed. Oral dosage with deoxycholate (1.5 to 3 g daily for a period of 4 to 10 weeks) resulted in a marked reduction of serum cholesterol concentration. Studies with 14C-labeled cholesterol demonstrated that deoxycholate administration decreased absorption of cholesterol from the human intestinal tract. In these subjects, the turnover rate of serum cholesterol was more rapid during therapy with deoxycholate than during control periods. Deoxycholate appeared to influence the intestinal flora as assessed indirectly by analysis of the types of neutral sterols eliminated with the feces. Decreased synthesis of cholesterol during deoxycholate administration uas demonstrated in a study with 14C-mevalonate. It is concluded that deoxycholic acid can have an important role in the regulation of cholesterol metabolism in humans.

The effect of thyroid activity on the rat anterior pituitary gland (APG) RNA synthesis was studied by measuring the incorporation of 3H-uridine into RNA. The incorporation of 3H-uridine both in vivo and in vitro into the RNA of APG was enhanced in thyroidectomized (THX) rats and depressed after administration of triiodothyronine (T3) to the THX animal. The thyroidectomy-enhanced in vitro uridine incorporation could be observed one week after the operation and the T3 inhibition on 3H-uridine incorporation was evident 4 hr after administration of 10 μg/100 g body weight of the hormone. Under the same experimental conditions, the effects of thyroidectomy and of T3 on liver RNA synthesis were the opposite of those found in the APG; thyroidectomy decreased and T3 increased the RNA synthesis in the liver. The incorporation of 3H-uridine into brain RNA was not altered under the different thyroid states. Adrenalectomy, castration or administration of hydrocortisone or testosterone to THX rats had no effect on 3H-...

A method employing zirconyl phosphate gel has been described for measuring the IF activity of human GJ. IF and B 12 binders which do not possess IF activity are differentiated by the use of IF specific antibody found in serum of PA patients. This antibody neutralizes the B 12 combining site of IF, but not the B 12 combining site of other binders present in GJ. For all practical purposes, no IF activity was found in the GJ obtained from 24 patients with pernicious anemia. GJ obtained from 11 controls of approximately the same age group as the PA patients contained about 50 times more IF than the PA gastric juice. There were no overlapping values.

Hypercholesterolemic subjects in a metabolic ward were kept under uniform dietary conditions until constant levels of serum cholesterol were observed. Oral dosage with deoxycholate (1.5 to 3 g daily for a period of 4 to 10 weeks) resulted in a marked reduction of serum cholesterol concentration. Studies with 14C-labeled cholesterol demonstrated that deoxycholate administration decreased absorption of cholesterol from the human intestinal tract. In these subjects, the turnover rate of serum cholesterol was more rapid during therapy with deoxycholate than during control periods. Deoxycholate appeared to influence the intestinal flora as assessed indirectly by analysis of the types of neutral sterols eliminated with the feces. Decreased synthesis of cholesterol during deoxycholate administration uas demonstrated in a study with 14C-mevalonate. It is concluded that deoxycholic acid can have an important role in the regulation of cholesterol metabolism in humans.

This investigation was designed to test the hypothesis that protein feeding stimulated glucagon secretion because amino acids liberated during protein digestion function as glucagon secretagogues. Rats were fed high-protein (HP) or control diets for 9--10 days and blood taken from the aorta or portal vein (PV) at 0800, 1300, 1700, 1900, 2100, and 2300 for determination of amino acids, glucose, insulin, and glucagon. Glucose, insulin, and glucagon of control rats showed little change. In HP rats, PV glucose rose during fasting (0800-1700) and declined during feeding (1700-0800), changes that reflected alterations of glucagon and insulin secretion. PV glucagon in HP rats that was elevated 2--4 times rose during fasting, whereas PV and arterial amino acids declined. HP feeding caused enhanced glucagon release that was associated with increased amino acids in PV and arterial plasma, especially the branched-chain group. Although these findings suggest that protein feeding promotes glucagon release because branched-chain amino acids are elevated, these amino acids are known to have little effect on alpha cell function. Thus, we conclude that protein feeding influences glucagon secretion through some mechanism other than increased blood amino acid levels.

The dose response and pharmacokinetics of orally administered calcitriol were investigated in normal humans. In one protocol, six volunteers received calcitriol 0.25 micrograms twice a day, 0.5 micrograms daily, and 0.5 micrograms twice a day, in successive weeks. Peak plasma levels of 1,25(OH)2D occurred 4 to 8 hours after ingestion of a single dose of 0.5 micrograms, with a return to baseline within 24 hours. The 8:00 AM calcitriol plasma levels were raised only when the drug was given twice daily. Urinary calcium excretion (UCa) was significantly increased from 199 +/- 19 mg/24 hr during the control period to similar levels of 302 +/- 26 mg/24 hr after 0.25 microgram twice a day and 284 +/- 31 mg/24 hr after 0.50 microgram daily. With 0.50 microgram twice a day, UCa was 417 +/- 36 mg/24 hr, a value greater than after the lower doses (p less than 0.05). In another protocol, fourteen volunteers received calcitriol 0.25 microgram, 0.5 microgram, and 1.0 microgram twice a day each for 14 days with intervening control periods of 2 weeks. A dose-related response in urinary calcium/creatinine excretion occurred. Thus, UCa (milligrams calcium per milligram creatinine) increased with calcitriol from 0.13 +/- 0.014 mg to 0.15 +/- 0.018 mg with 0.25 microgram twice a day, from 0.13 +/- 0.010 mg to 0.22 +/- 0.022 mg with 0.5 microgram twice a day, and from 0.12 +/- 0.012 mg to 0.23 +/- 0.012 mg with 1 microgram twice a day (p less than 0.05 with 0.25 microgram, p less than 0.01 with 0.5 and 1 microgram twice a day).(ABSTRACT TRUNCATED AT 250 WORDS)

Rats on a vitamin A-deficient diet for 4 weeks showed a slight increase in susceptibility to Trypanosoma cruzi infection; however, pair-fed control rats were equally susceptible, suggesting that inanition was responsible for the lowered resistance. After 13 weeks on the vitamin A-deficient diet, rats were significantly more susceptible to T. cruzi infection than the pair-fed control rats. Spontaneous bacterial infection was observed in rats on the deficient diet and appeared to be a contributing cause of death in some of the inoculated rats.

Studies on the incorporation of radioactive amino acids into total protein of the anterior pituitary gland (APG) of rats were performed in order to learn more about the effects of thyroid hormones on this gland. APG incubated in Krebs-Ringer phosphate buffer (with 250 mg/100 ml glucose, without Ca++) incorporated 14C-leucine into total protein at a linear rate for about 8 hr. Omission of glucose from the incubation medium significantly decreased the rate of incorporation, while the addition of amino acids to Krebs-Ringer buffer which contained glucose had no effect. The APG from thyroidectomized (THX) rats, but not from adrenalectomized or castrated rats, had a higher rate of incorporation of radioactive amino acids than the APG of euthyroid rats. This thyroidectomyinduced incorporation could be reduced to normal within 12 hr after a single injection of either triiodothyronine (T3), thyroxine (T4) or tetraiodothyroacetic acid. Direct addition of T3 into the incubation medium also suppressed the enhanced 1...