Cardiac resynchronization in chronic heart failure.

Background: Previous studies have suggested that cardiac resynchronization achieved through atrial-synchronized biventricular pacing produces clinical benefits in patients with heart failure who have an intraventricular conduction delay. We conducted a double-blind trial to evaluate this therapeutic approach.

Methods: Four hundred fifty-three patients with moderate-to-severe symptoms of heart failure associated with an ejection fraction of 35 percent or less and a QRS interval of 130 msec or more were randomly assigned to a cardiac-resynchronization group (228 patients) or to a control group (225 patients) for six months, while conventional therapy for heart failure was maintained.

Dietary protein and chronic toxicity of 1,2-dimethylhydrazine fed to mice.

1,2-Dimethylhydrazine-HCl (DMH-2HCl) is derived from the natural toxin cycasin, and is extensively used to induce cancers in experiments with rodents. We examined the toxicity of DMH-2HCl, incorporated into purified diets varying in protein, to determine concentrations compatible with long-term survival in B6C3H1 mice. Initial studies showed single-dose oral LD50 values (95% confidence intervals) of 26 (18-32) mg DMH-2HCl/kg body weight for males, and 60 (53-65) for females.

Effects of dietary protein, fat and energy intake during an initiation phase study of 7,12-dimethylbenz[a]anthracene-induced breast cancer in rats.

A factorial experiment was conducted to examine the effects of dietary protein (8, 16, 32% of energy from casein) and dietary fat (12, 24, 48% of energy from corn oil) on the initiation of 7,12-dimethylbenz[a]anthracene (DMBA)-induced breast carcinogenesis in rats. Forty weanling female Sprague-Dawley rats were assigned to each of nine diets fed ad libitum. After 4 wk each rat received DMBA (20 mg/kg) via gastric intubation.

Plasma amino acids and excretion of protein end products by mice fed 10 or 40% soybean protein diets with or without dietary benzo[a]pyrene or 1,2-dimethylhydrazine.

The effects of two carcinogens benzo[a]pyrene (BP) and symmetrical 1,2-dimethylhydrazine dihydrochloride (DMH), on plasma amino acid concentrations and on excretion of lipids and nitrogenous metabolites were studied in 7- to 8-wk-old male and female B6C3F1 mice. BP and DMH were fed at concentrations of 0.3125 and 0.