Search PubMed⌕ Search

Biomedical subjects

L M Klevay

Publications and source records attributed to L M Klevay.

At least 91 records · Page 5Linked to original sources
PubMed1981

Plasma lecithin: cholesterol acyltransferase in copper-deficient rats.

Some groups of people with high risk of ischemic heart disease have low lecithin:cholesterol acyltransferase activity in plasma and vice versa. Because we hypothesized a relationship between inadequate copper nutriture and the risk of ischemic heart disease, we measured plasma lecithin: cholesterol acyltransferase in copper deficient male Sprague-Dawley rats. Deficiency was verified by the presence of anemia, hypercholesterolemia and low copper concentrations in kidney and skeletal muscle. Three experiments showed a significant decrease (22-32% reduction) in enzyme activity in deficiency. Copper may be required for the synthesis of the enzyme or as a constituent of the enzyme.

Animals↗
PubMed1981

Abnormal electrocardiograms in rats deficient in copper.

According to a new hypothesis based on epidemiologic observations, iatrogenic maneuvers, natural occurrences, and animal experiments, absolute or relative deficiency of copper is of prime importance in the etiology of ischemic heart disease. Male weanling rats were made copper deficient with a purified diet containing 0.79 microgram Cu/g diet and containing all other nutrients known to be essential. Deficiency was verified by a 39% increase in cholesterolemia. Electrocardiograms of copper-deficient rats showed several abnormalities including S-T segment depression for one-third to one-half of the R-R interval, bundle branch block with R waves three times normal height and width, Q waves, and second- and third-degree heart block. Copper deficiency shortened the lives of the rats by 73%. Copper deficiency is the only nutritional insult that has produced rapid unfavorable alterations in lipid metabolism, cardiac and arterial anatomy, and cardiac electrophysiology. Copper metabolism may be important in the etiology of ischemic heart disease and in the arrhythmias associated with the consumption of liquid-protein diets.

Animals↗
PubMed1981

Dietary fiber and personality factors as determinants of stool output.

We examined effects of fiber on stool output, since this is one of the primary mediating variables for the hypothesized relationship between fiber and disease. Total neutral detergent fiber in the dietary fiber source was predictive of stool weight but not frequency. Substantial individual differences in stool output remained when dietary factors were controlled. Personality measures were used to predict stool weight and frequency independently of diet, and accounted for about as much variance in stool output as did dietary fiber. These results suggest that personality factors predispose some persons to low stool output. These individuals may benefit particularly from dietary fiber.

Adolescent↗
PubMed1980

The human requirement for copper. I. Healthy men fed conventional, American diets.

Each of 13 men was fed diets made from conventional foods for two to seven periods lasting 30 days in a metabolic ward. There was a total of 47 experimental periods. Supplementation of the basal diet with each of several bran or other fiber sources was done in no particular order; each subject was fed the unsupplemented diet for at least one period. The diet was designed to contain amounts of essential nutrients close to the Recommended Dietary Allowances; it resembled the "average" American diet as it contained 16% protein, 40% fat, and 44% carbohydrate. Only minimal variation in energy intake and physical activity of the men was permitted; body weight remained constant within +/- 2%. Copper in food, feces, and urine was measured during the last 12 days of each period. Linear regression of balance (intake minus the sum of fecal and urinary losses) revealed a daily requirement of 1.30 mg (95% confidence limits of 1.24 to 1.35 mg). On consideration of a calculated surface loss of 0.25 mg/day, the requirement is 1.55 mg/day. The requirement was unaffected by the type of fiber source. A review of published data revealed that this requirement substantially exceeds the amount of copper found in many conventional diets.

Copper↗
PubMed1980

The influence of copper and zinc on the occurrence of ischemic heart disease.

The zinc/copper hypothesis, which invokes relative or absolute deficiency of copper in the etiology of ischemic heart disease, was described. The belief that calcium (and, perhaps, magnesium) is a substance in hard water which protects against ischemic heart disease by altering copper and zinc metabolism was presented. The amounts of copper and zinc in drinking water usually are too small to produce important increases in the amounts of these elements in diets. Occasionally tap water high in copper may be an important supplement to a diet low in copper.

Animals↗
PubMed1980

Utility of serum ferritin as a measure of iron deficiency in normal males undergoing repetitive phlebotomy.

Hematologic indices and iron balance data were obtained on 22 normal male volunteers who were subjected to a mean +/- SD phlebotomy of 164 +/- 34 ml whole blood/mo while living in a controlled environment. Over an average stay of 5 mo, volunteers did not develop anemia, but did display a reduction in iron stores that was quantitated by measurement of serum ferritin and iron balance. The percent saturation of transferrin and the usual erythrocyte parameters did not reflect changes in iron status. Loss of iron, which was calculated from quantitative phlebotomy and iron balance data, showed that a decrease of 1 ng of serum ferritin represented a loss of 4.5 +/- 5.3 mg of iron in 10 men whose initial serum ferritins were greater than 25 ng/ml, and 25.3 +/- 58.8 mg of iron in 7 men whose initial serum ferritins were less than 25 ng/ml. The period required for 3 volunteers who consumed a self-selected mixed diet at home to replace their depleted iron stores to prephlebotomy levels was about 4.5 mo. The sensitivity of serum ferritin as an index of iron stores was affirmed. In addition it was found that normal men who were consuming a mixed diet containing about 15 mg of iron daily and losing blood at a rate of 164 +/- 34 ml/mo did not increase their iron absorption sufficiently to compensate for the iron loss.

Adult↗
PubMed1979

Evidence of dietary copper and zinc deficiencies.

The mean daily amounts of copper and zinc found in hospital diets by atomic absorption spectrometry were 0.76 and 9.4 mg, respectively. Comparison of these diets with published data showed median daily amounts of copper and zinc to be 0.78 and 12.0 mg, respectively, for 20 diets made from conventional foods. These amounts of copper and zinc are less than the 2 mg of copper and 13 mg of zinc thought to be required daily by adults. Hospital diets and perhaps diets in general seem to be low in copper and zinc; the amounts of copper are lower than those of zinc in comparison with respective requirements. Common dietary amounts of these elements may cause health problems.

Adult↗
PubMed1979

Diets deficient in copper and zinc?

Hospital diets, and, perhaps, diets in general may be low in copper and zinc, with the diets being lower in copper than zinc in comparison to requirements. Several human diseases or pathologic conditions of unknown etiology have similarities to findings in deficient animals. Thus nutritional status and metabolism of copper may be important in anemia, ischemic heart disease, rheumatoid arthritis, osteoporosis, multiple sclerosis and seborrheic dermatitis. Zinc may be involved in growth failure, acne, difficulties of labor, congenital abnormalities and wound healing. Whether or not dietary amounts of copper and zinc are involved in the etiology or the pathogenesis of these conditions can be determined by clinical investigation.

Acne Vulgaris↗
PubMed1979

Effects of some cereal brans and textured vegetable protein on plasma lipids.

The hypothesis that dietary fiber lowers serum cholesterol was tested in 10 healthy men, 19 to 54 years old, who ate a mixed diet similar to the diets of many American adult males, that contained 16% of calories as protein (70% from animal), 40% as fat (P/S = 0.3), 44% as carbohydrate (9% of calories as sucrose) and 3 g of crude fiber. The energy intake ranged from 2700 to 3500 kcal adjusted to their height and weight. Weight and fitness were held constant. After 30 days of equilibration on the basal diet, they ate 26 g of either soft white wheat bran, corn bran (CB), soybean hulls (SH), textured vegetable protein, or hard red spring wheat bran (HRS) for periods of 28 to 30 days each in no particular sequence. Each fiber was fed to four to six subjects. The dietary fiber contents of soft white wheat bran, CB, SH, and HRS were: 44, 92, 87, and 51%, respectively. Mean daily fecal weight increased (P less than or equal to 0.01) from 72.4 to 144, 68 to 128, and 81 to 151 g when CB, SH, and HRS were fed respectively. No effects were noted with soft white wheat bran or textured vegetable protein. Total plasma cholesterol decreased 12% with HRS (P less than or equal to 0.05) and 14.0% with SH (P less than or equal to 0.05). Low density lipoprotein cholesterol decreased 21% with HRS (P less than or equal to 0.05). High density lipoprotein cholesterol did not change with any of the dietary fiber sources nor did the ratio of high density lipoprotein cholesterol to total cholesterol. Some triglyceride lowering effect was seen with all sources of dietary fiber (P less than or equal to 0.01). There was a significant direct correlation between the area under the oral glucose tolerance curves and the levels of total cholesterol (r = 0.57, P less than or equal to 0.0001) and low density lipoprotein cholesterol (r = 0.49, P less than or equal to 0.0007), and between fasting plasma glucose and triglycerides (r = 0.32, P less than or equal to 0.03). Results were replicated when subjects were fed the same fiber source on two occasions at 2 to 4 month intervals.

Adult↗
PubMed1978

Cholesterolemia and cardiovascular abnormalities in rats caused by copper deficiency.

The association of copper with cardiovascular disease and a possible involvement of copper in the metabolism of cholesterol prompted the study on hypercholesterolemia mediated by copper deficiency. Copper deficient rats were found to exhibit a highly significant cholesterolemia (P less than 0.001), and plasma cholesterol showed a significant correlation with hepatic copper concentration (P less than 0.03). Two copper deficient rats died with hemothorax. The hearts of copper deficient rats were hypertrophied with large areas of hemorrhage, inflammation and focal necrosis. Prominent subendocardial fibroplasia was evident in copper deficient animals. The myocardial arteries of copper deficient rats were normal, however, aortas showed large areas of distorted and depleted elastic fibers. The results are discussed in terms of a possible role for copper in cholesterol metabolism, and in the pathogenesis of atherosclerosis.

Animals↗
PubMed1978

Influence of dietary fiber on trace element balance.

Five adult male volunteers were fed a diet containing (as percent of calories) 16% protein, 40% fat, and 44% carbohydrate, a diet similar to that consumed by many American males. Twenty-six grams of soft white wheat bran or corn bran were added to the daily bread, and the effects on zinc, iron, and copper balance were assessed during the last 12 days of each 30-day study period. The soft white wheat bran appeared to decrease retention of zinc in four subjects but not significantly so. Iron retention was similar in all three treatments. Copper balance was improved by addition of soft white wheat bran and to a lesser degree by corn bran. An apparent copper requirement of 1.28 mg/day for the volunteers was calculated by regression analysis.

Adult↗
PubMed1978

Hair as a biopsy material. V. Hair metal as an index of hepatic metal in rats: copper and zinc.

Hair copper in 500 day-old adult rats was found to correlate directly with copper in whole liver (P less than 0.001) and the subcellular liver nuclear (P less than 0.022), and cytosol fractions (P less than 0.001). An inverse correlation was found between copper in liver microsomes and plasma cholesterol (P less than 0.044). Similar data analysis for zinc showed no significant correlations (P greater than 0.05). The determination of copper in hair may be useful for assessing total liver copper content in human beings. Copper in liver microsomes may participate in the control of plasma cholesterol.

Animals↗
PubMed1978

Intake of nickel and vanadium by humans. A survey of selected diets.

The nickel and vanadium contents of nine institutional diets were determined by atomic absorption spectrometry with background correction. The following values were obtained for nickel: mean concentration, 0.27 +/- 0.02 microgram/g (dry weight); range, 0.19 and 0.41 microgram/g; mean intake, 165 +/- 11 microgram/day or 75 +/- 10 microgram/1000 cal. The respective values for vanadium were: 0.032 +/- 0.004 microgram/g (dry weight); 0.019 to 0.050 microgram/g; 20.4 +/- 2.3 microgram/day or 8.9 +/- 1.0 microgram/1000 cal. Thus, vanadium is present at approximately one order of magnitude less than nickel.

Diet Surveys↗