Intimal thickening in the coronary arteries of infants and children as an indicator of risk factors for coronary heart disease.

Narrowings of the coronary arteries were measured in 94 infants aged less than 1 year who died in hospital and 102 1- to 16-year-old children who died accidentally. The arteries were transformed mathematically to circles. The degree of narrowing caused by intimal thickening was determined as the ratio of intimal area to the original luminal area.

Assessment of microvascular clamping injury of rat aorta by histochemical examination of oxidoreductases.

To assess clamping injury to the rat abdominal aorta, the activities of two oxidoreductases, lactate dehydrogenase (LD) and succinate dehydrogenase (SD), were estimated histochemically at various points in time after clamping the aorta for 30 min (group A) or 60 min (group B) with two kinds of microvascular clips. Areas of depressed LD and SD activity were found 3 days after surgery in group A and 1 day and 3 days after surgery in group B. The random, intermittent occurrence of the changes in enzyme activity within the time groups pointed to a mild trauma induced by the clips.

Assessment of metabolic activity in aortic vein grafts in rats by histochemical examination of hydrolases.

The metabolic pattern of aortic vein grafts in rats was studied by estimating histochemically the activity of the hydrolytic enzymes alfa-esterase, aminopeptidase, adenosine triphosphatase, acid phosphatase and alkaline phosphatase. The enzyme activity was lowest in the 16 hour and 1 day old grafts, and recovery was noted at three days. Five days after transplantation the enzyme activities were higher than in the non-transplanted veins.

Enzyme histochemical studies on microarterial grafts in rats.

In order to evaluate the duration and localization of the metabolic changes elicited by the procedure of transplantation, the sequential changes in enzymatic activity of carotid artery grafts in rats were evaluated by histochemical demonstration of the activity of two oxidoreductases, lactate dehydrogenase (LD) and succinate dehydrogenase (SD), and two hydrolytic enzymes, adenosine triphosphatase (ATPase) and alkaline phosphatase (AFOS). The most intense staining for ATPase, LD and SD was seen in the media, both in the grafts and in the adjacent carotid artery. The activity of AFOS was concentrated to the inner parts of the adventitia.