John J. Coyle

Vitamin B12 absorption following human intestinal bypass surgery

Adaptation of vitamin B12 absorption by small intestine has been suggested by experimental and clinical studies. Five partial ileal bypass patients and ten jejunoileal bypass patients were studied for adaptation of B12 absorption following surgery. Adaptation of vitamin B12 absorption could not be demonstrated in either group. Few of the patients on an individual basis demonstrated adaptation. Parenteral B12 should be given to all patients who undergo bypass surgery unless evidence of persistent normal B12 absorption has been obtained.

Sterol dynamics following portacaval shunt

Abstract This study reports lipid studies on dogs up to 44 weeks following portacaval shunt. We have shown portacaval shunt to be associated with significant decreases in plasma cholesterol and triglyceride levels in the dog. Cholesterol synthesis and absorption appear to be unchanged following operation when compared to control animals. Two-hour postprandial serum bile acids are fortyfold greater in shunted animals than in control dogs. Further studies of the interrelationship of bile acid and cholesterol metabolism following portacaval shunt are suggested.