R. Foster Scott

Comparison of the amount of coronary arteriosclerosis in autopsied East Africans and New Yorkers

Abstract A comparison of the degree of coronary arteriosclerosis and number of myocardial infarcts in 117 autopsied East Africans and 137 New Yorkers was made. In forty-three subjects from each series (thirty-four men and nine women) matched for age and sex, the amount of coronary arteriosclerosis was generally much higher in the New York autopsy series, although the East Africans were not free from arteriosclerosis, and some overlapping occurred between the two groups. In this same matched group there were seventeen myocardial infarcts among the Americans, while none were found in the East African autopsy series. Comparative studies of blood and tissue lipid patterns, as well as clot lysis in the two groups, are now being carried out in an attempt to obtain other information pertaining to these findings.

Geographic Pathology of Myocardial Infarction

Abstract Myocardial infarction is common in the United States and rare in certain parts of the Orient and Africa. Such geographic variations in occurrence rates of myocardial infarction could be due either to genetic factors or to environmental factors such as diet, climate and socioeconomic factors. If the genetic factor is the main factor responsible for the apparent geographic differences in the occurrence rates of myocardial infarction, the Orientals and Negroes who immigrated to the United States should maintain their low occurrence rates at least to some extent. On the other hand, if environmental factors are mainly responsible for variations, the occurrence rates of myocardial infarcts in those people should have changed considerably when they moved into an entirely different environment. To investigate the importance of genetic compared to environmental factors, we have analyzed all death certificates, autopsy data from 17 general hospitals and from coroners in San Francisco, and from 3 general hospitals in Los Angeles for the period 1956 to 1960. Detailed information was obtained on all Orientals, including Chinese, Japanese and Filipinos. All the autopsied Oriental cases were compared with age-sex matched cases from the white populations. Similar information was obtained from Japan, Korea, Uganda and Nigeria, and from Negro and white groups in New Orleans and Albany. The average length of residence of the Orientals in San Francisco and Los Angeles was approximately 30 years, and the occurrence rates of myocardial infarction in those Orientals were much higher in all age groups than in the Orientals in their home lands, and approached those of the whites. In the male 50 to 59 age group which included substantial numbers of cases for meaningful comparisons, the occurrence rates of myocardial infarction were similar in both racial groups. This suggests that environmental factors seem to play a major role among the Orientals in the etiology of myocardial infarction and coronary thrombosis, and the genetic factor plays a relatively minor role, if any. In the Uganda and Nigeria autopsy series, myocardial infarction was almost nonexistent. Negroes in the United States have lived in this country for many generations and the occurrence rates of myocardial infarction among them are significantly greater than among Negroes in Africa and approach the occurrence rates of whites. As with the Orientals, this suggests that environmental factors are more important in the etiology of myocardial infarction than genetic factors in Negroes in the United States. However, definitive conclusions cannot be drawn for many reasons including the fact that whites, Orientals and Negroes do not represent pure genetic strains since all three groups have immigrated to the United States only a few generations ago from diverse regions and have not remained as sharply defined races.

Chemico-anatomic studies of arteriosclerosis and thrombosis in diabetics: II. Fatty acids of adipose tissue and plasma lipids in several groups of North American diabetics and nondiabetics

Abstract It has been well established by both clinical and autopsy studies that myocardial infarction is much more common in North American white diabetics compared with nondiabetics. In this study the possible interrelationships between myocardial infarcts, diabetes and adipose tissue fatty acids and plasma lipids were studied by comparing diabetics unselected as to the presence or absence of complications with age- and sex-matched nondiabetics. Adipose tissue fatty acids were measured because of the suggested abnormal release of fatty acids from tissue stores in the diabetic. Only palmitic acid of six adipose tissue fatty acids compared in diabetics and nondiabetics was found to be significantly different, and this only in female diabetics, compared to female nondiabetics. The biologic significance of this finding is questionable. The finding of similar linoleic acid values in North American diabetics and nondiabetics suggests that there is no deficiency of linoleic acid in the diabetic adipose tissue stores contributing to the greater incidence of myocardial infarction in this group. Among plasma lipids, no difference was found in comparing plasma cholesterol levels. However, triglycerides (in both male and female diabetics) and lipid phosphorus (in female diabetics) were found to be elevated when compared to levels in nondiabetics. The elevated serum triglycerides in the diabetic group in this study is in keeping with the serum triglyceride levels found in other groups of diabetics who have strikingly different frequencies of myocardial infarction. North American white, North American Negro, and East African diabetics, with a high, intermediate, and low frequency of myocardial infarction respectively showed high, intermediate, and low levels of serum triglyceride. Although the evidence is far from complete, there is at least some reason to believe that plasma lipids are involved in the clotting mechanism. It is possible that the elevated plasma lipids found in this group of diabetics may explain the greater susceptibility to coronary artery thrombosis and myocardial infarction in diabetes.

Lack of Correlation Between Fatty Acid Patterns in Adipose Tissue and Amount of Coronary Arteriosclerosis

T HIS study is one of a seniesm -7 designed to explore the possible relationships between the anatomic manifestations of coronary arterial disease and lipid patterns of blood and tissue. This report deals specifically with a comparison between the amount of coronary arteriosclerosis (with or without myocardial infancts) and fatty acid patterns of adipose tissue (as determimied by vapor phase chromatography) in fifty-seven New Yorkers who were examined at autopsy. In subsequent reports similar comparisons will be made using persons from other geographic areas,

Effects of methyl prednisolone and colchicine on the development of aortic atherosclerosis in swine

The effect of methyl prednisolone and colchicine on the development of both the early proliferative and advanced atherosclerotic lesion in swine aorta was studied. In order to accelerate the development of atherosclerosis, the abdominal aortic endothelium was partially denuded by a balloon before the animals were placed on either a moderate or severe hypercholesterolemic diet. Neither drug in either dietary group inhibited the development of atherosclerosis. Swine receiving methyl prednisolone and severe hypercholesterolemic diet actually had a significantly greater number of the advanced necrotic lesions and more arterial calcification than the group receiving the atherogenic diet alone. In addition, the thoracic aorta of swine receiving the moderate hypercholesterolemic diet and methyl prednisolone showed larger amounts of lipid than did the non-drug fed control group. In swine receiving the moderate hypercholesterolemic diet, methyl prednisolone significantly raised serum cholesterol levels. Colchicine only slightly worsened the atherosclerosis in swine aorta and had no effect on serum cholesterol levels.

Electron microscopy study of chyle from rats fed butter or corn oil

Abstract In both man and experimental animals butter and corn oil appear to have different biologic effects. We hoped that an electron and phase microscopy study of the mechanics of lipid adsorption following meals of butter or corn oil might provide insight into the biologic action of these two fats. Jejunal mucosa and chyle from the visceral lymphatics of butter and corn oil-fed rats were examined in osmium tetroxide fixed sections embedded in Epon, and chyle was examined directly by phase microscopy. The appearance of lipid in the jejunal mucosa confirmed a previous report that jejunal fat was different in appearance in butter and corn oil-fed rats. In addition, the appearance of fat in the chyle was strikingly different depending on the type of fat fed. In the butter-fed rats the fat, presumably in the form of chylomicrons, appeared either as minute forms with irregular borders, or as large globular masses measuring from 5 to 20 microns in diameter. The lipid in the visceral lymphatics of corn oil-fed rats appeared for the most part as round, smooth bordered spheres up to one micron in diameter with densely staining edges. Rats fed water showed virtually no osmophilic masses which could be interpreted as fat. The meaning of these differing physical appearances of lipid with regard to their biologic effect is not clear. It is possible, however, that the different physical characteristics of chylomicrons from butter and corn oil in the rat may in part account for the different biologic actions of the two fats.

Chemico-anatomic studies in geographic pathology. A comparison of lipids in New Yorker and African coronary arteries.

Abstract Many young adult New Yorkers have previously been shown to have a greater amount of arteriosclerosis than young adult Africans. This study of 5 Africans and 20 New Yorkers was carried out to learn if rather complex chemico-anatomical comparisons of coronary arteries of New Yorkers and Nigerians might provide some insight into the quantiative differences in arteriosclerosis in the two groups, and provide information to enable us to plan a large scale study of such groups. As expected, some of the coronary arteries of New Yorkers of comparable age to the Africans showed considerably more arteriosclerosis and higher total lipid contents than the Nigerian coronary arteries. The fatty acid content of the two groups of arteries, New Yorker and Nigerian, were also somewhat different. The New Yorker coronary arteries had higher oleic acid, and a lower palmitic and stearic acid than did the Nigerian arteries. The fatty acid patterns suggested that the kind of arteriosclerosis, as well as its amount, might be different in the two groups of arteries analyzed. While more investigation needs to be done with much larger numbers, and a broader range of fatty acids, this qualitative difference in the coronary arteries of young New Yorkers and Nigerians may in part explain the different biologic behavior of arteriosclerosis in the two groups.

Clot-strength and clot-lysis in rats fed thrombogenic diets☆

Abstract Butter appears to have a different biologic effect than corn oil regarding the development of intra-arterial thrombi and infarcts in rats. Rats receiving a diet containing 40% butter (plus cholesterol, propylthiouracil, and other ingredients) develop thrombi with myocardial and renal infarcts, together with an increased clot-lysis time. If corn oil is substituted for butter no thrombi or infarcts have been found and the clot-lysis times are shorter than that of the butter-fed animals. In order to elucidate the mechanism of the thrombogenic action of butter when fed to rats, the comparative strengths of clots formed from the plasma of rats fed butter or corn oil (plus other ingredients) or a stock diet, were measured using binding power in a thrombelastograph as one index of clot-strength. In addition, clot-lysis and plasma cholesterol determinations were done on all groups. The binding powers of the clots formed from the plasma of butter- and corn oil-fed rats were not significantly different, but both fats produced clots of far greater binding power than did the low fat, stock diet. The clot-lysis times of the same butter-fed group of rats was significantly greater than that of the corn oil group. Both fat-fed groups had a longer clot-lysis time than did the stock diet group of rats. The finding of equal binding powers but different clot-lysis times in corn oil- and butter-fed rats suggests that the thrombogenic property of the 40% butter diet is due either to alterations in the lytic system secondary to the butter diet, or to aspects of clot-strength not reflected by binding power.

Functional change in hepatic mitochondria of swine fed ethylchlorophenoxyisobutyrate

Abstract Hepatic mitochondria of swine fed ethylchlorophenoxyisobutyrate (CPIB) at a level of 0.3% (w/w) for 8 weeks showed partial uncoupling of oxidative phosphorylation and increased state 4 QO2 values. Both cytochrome oxidase and the calculated theoretical mitochondrial protein were increased per gram of total liver. Whether related or not these changes were accompanied by the appearance of tubular spiral structures within the mitochondria. Swine fed CPIB for 4 weeks showed similar but fewer functional and morphologic changes. Feeding the drug 1 week produced no abnormalities of oxidative phosphorylation or QO2 values, and no morphologic changes were present. However, at this time calculated theoretical mitochondrial protein, cytochrome oxidase, and monoamine oxidase activities were already increased per unit of liver weight.

Geographic Pathology of Myocardial Infarction: Part I. Myocardial infarction in orientals and whites in the United States; Part II. Myocardial infarction in orientals in Korea and Japan; Part III. Myocardial infarction in Africans in Africa and negroes and whites in the United States; Part IV. Measurement of amount of coronary arteriosclerosis in Africans, Koreans, Japanese and New Yorkers☆

Abstract Myocardial infarction is common in the United States and rare in certain parts of the Orient and Africa. Such geographic variations in occurrence rates of myocardial infarction could be due either to genetic factors or to environmental factors such as diet, climate and socioeconomic factors. If the genetic factor is the main factor responsible for the apparent geographic differences in the occurrence rates of myocardial infarction, the Orientals and Negroes who immigrated to the United States should maintain their low occurrence rates at least to some extent. On the other hand, if environmental factors are mainly responsible for variations, the occurrence rates of myocardial infarcts in those people should have changed considerably when they moved into an entirely different environment. To investigate the importance of genetic compared to environmental factors, we have analyzed all death certificates, autopsy data from 17 general hospitals and from coroners in San Francisco, and from 3 general hospitals in Los Angeles for the period 1956 to 1960. Detailed information was obtained on all Orientals, including Chinese, Japanese and Filipinos. All the autopsied Oriental cases were compared with age-sex matched cases from the white populations. Similar information was obtained from Japan, Korea, Uganda and Nigeria, and from Negro and white groups in New Orleans and Albany. The average length of residence of the Orientals in San Francisco and Los Angeles was approximately 30 years, and the occurrence rates of myocardial infarction in those Orientals were much higher in all age groups than in the Orientals in their home lands, and approached those of the whites. In the male 50 to 59 age group which included substantial numbers of cases for meaningful comparisons, the occurrence rates of myocardial infarction were similar in both racial groups. This suggests that environmental factors seem to play a major role among the Orientals in the etiology of myocardial infarction and coronary thrombosis, and the genetic factor plays a relatively minor role, if any. In the Uganda and Nigeria autopsy series, myocardial infarction was almost nonexistent. Negroes in the United States have lived in this country for many generations and the occurrence rates of myocardial infarction among them are significantly greater than among Negroes in Africa and approach the occurrence rates of whites. As with the Orientals, this suggests that environmental factors are more important in the etiology of myocardial infarction than genetic factors in Negroes in the United States. However, definitive conclusions cannot be drawn for many reasons including the fact that whites, Orientals and Negroes do not represent pure genetic strains since all three groups have immigrated to the United States only a few generations ago from diverse regions and have not remained as sharply defined races.