Lalitha Murthy

Atomic absorption determination of zinc, copper, cadmium, and lead in tissues solubilized by aqueous tetramethylammonium hydroxide

Abstract Rat liver and kidney homogenates and homogeneous rat hair samples were prepared for atomic absorption spectrophotometric analysis by digestion with an appropriate concentration of aqueous tetramethylammonium hydroxide (TMAH). The endogenous tissue levels of Zn, Cu, Cd and Pb, the reproducibility of the analyses, and the recovery of added metal standards compare favorably with the results obtained by standard wet ashing procedures using concentrated nitric acid or nitric-perchloric acids. The use of 5% HNO 3 standard curve in calculations for the TMAH-treated samples leads to slightly lower results compared to the method of additions due to viscosity and surface tension effects on the aspiration rate of these samples. Moreover, the TMAH digestion method allows faster and safer processing and handling of samples in comparison to acid digestion procedures.

δ-Aminolevulinate dehydratase, a zinc dependent enzyme

Abstract Erythrocyte and liver tissue δ-aminolevulinate dehydratase activity was determined in rats fed a semipurified diet under controlled nutritional intake of zinc and copper. A significant decrease in enzymatic activity was observed in animals fed low zinc diet, while dietary copper had no effect. In vitro addition of zinc to the erythrocyte preparations obtained from rats on low zinc diet produced a slight increase in enzymatic activity. It appears that, even though zinc may be the metal ion activator of δ-aminolevulinate dehydratase, the requirement of this metal is at the site of synthesis of this enzyme.

Copper deficiency effects on cardiovascular system and lipid metabolism in the rat; the role of dietary proteins and excessive zinc

Weanling rats were fed a copper-deficient purified diet. The effects of varying the type of protein and supplements of copper and zinc on cardiovascular pathology and some biochemical parameters were investigated. It was found that cardiomyopathy developed in the copper-deficient groups. Milk powder caused significant exacerbation of this development relative to dietary casein or egg white. Angiopathy developed only when dietary zinc was 20 ppm. Dietary copper did not change this situation. Serum cholesterol was elevated when copper was low and casein or milk powder were the protein source. The data point to an interaction between type of protein and dietary copper or zinc in the pathogenesis of cardiovascular lesions.

Modifications in food consumption patterns reported by people from India, living in Cincinnati, Ohio

Surprisingly little research has been conducted to identify modifications of food habits made by people who have immigrated to the United States from India, South Asia. This study helps to bridge an information gap by assessing previous and present food habits reported by a group of people from India living in Cincinnati, Ohio. Acculturation of food consumption patterns of Indian immigrants to the United States may be manifested in the form of modification of vegetarian status, alteration in meal patterns and change in the frequencies of use of ethnic foods, as well as foods from other cultures available in America. Indian immigrants to the United States should probably be warned that, along with the adoption of Western food habits, certain health concerns may come along as part of the assimilative package.

A comparison of some biochemical properties of dissociated liver cells and of slices.

Summary Rat liver cells prepared by using various dissociating solutions were unable to accumulate K+ from the media. The respiration of dissociated liver cells in the presence of succinate was not altered by the presence of 3 × 10-5 sodium tetraphenylborate in the dissociating media. Accumulation of K+ and respiration in the presence of succinate of rat liver slices were shown to be subject to inhibitory action of TPB on a log-dose basis in the concentration range of 3 × 10-5 to 3 × 10-3 M. Liver slices exposed to 3 × 10-3 M TPB showed the same loss of ability to accumulate K+ which was shown by liver cells dissociated by any of the methods tried, whether TPB was present or not. From these studies it is concluded that freshly isolated cells which exhibit oxygen uptake in the presence of succinate are unable to perform other metabolic functions, such as K+ uptake.

Effects of copper deficiency on the cardiovascular system of the rat

Weanling male rats were fed a copper-deficient diet devoid of cholesterol. The effects of varying the source of carbohydrate and supplements of copper and zinc on cardiovascular pathology and some biochemical and physiological parameters were investigated. It was found that cardiomyopathy developed in copper-deficient groups. Sucrose, in contrast to starch or starch:lactose (1:1), caused significant exacerbation of this situation. Increasing dietary Cu to 8 ppm prevented or minimized the development of cardiomyopathy. Angiopathy occurred only when dietary zinc was at the lower level (20 ppm). Dietary copper supplements to 8.0 ppm did not alter this situation, but 120 ppm Zn in the drinking water did reduce the angiopathy almost to the control level, except in the groups in which sucrose was fed. Serum cholesterol was only elevated significantly over the control value when dietary copper was deficient and sucrose was the carbohydrate source. The data point to independent action of dietary copper or zinc on the myocardium or vessels, respectively, with sucrose interacting to make copper and zinc supplements less active than when starch or starch/lactose was fed.

Isolation of Metal-Binding Agents from Coal Dust and their Effects on Mitochondrial Function

Abstract Bituminous coal samples from mines in Utah and Pennsylvania were extracted with a series of organic solvents, used in order of increasing polarity. The extracted materials, amounting to 58–70 mg/g of Utah coal and 12–15 mg/g of Pennsylvania coal, were each fractionated on a carboxymethyl cellulose column in the Cu (II) form. The copper-complexing fractions for Utah and Pennsylvania were 30% and 22%, respectively, of the total extract. Copper-binding capacity was 400 ug copper/g Utah coal and 40 ug/g for Pennsylvania. The copper-binding ligands from both coals uncoupled oxidative phosphorylation of isolated rat liver mitochondria, a system containing copper and iron metalloenzymes. The inhibitory activity per gram of extracted material was higher for Pennsylvania than Utah. These results suggest that the extraction and absorption of metal-binding agents from coal may adversely alter vital cellular energetics. Coal dust and its effects on human health is of concern because of the prevalence of resp...

Relationship of sufficient and abundant level of minerals to lipid and lipoprotein metabolism in male rats

Abstract Recent studies have shown the effects of inidividual essential metals, or simple combinations of them, on lipid metabolism. Perturbations in blood or liver lipids due to 1% dietary cholesterol were seen in rats fed purified diets containing National Research Council (NRC) recommended levels of minerals, while rats fed chow were protected against these effects. To determine the effects of dietary minerals on lipids and lipoproteins, a study was conducted using male rats fed purified diets with two mineral mixtures, one equivalent to NRC recommendations and the other with levels similar to those present in chow. The effects of 1% dietary cholesterol in these groups were compared with those observed in chow-fed rats. The added mineral mixture affected the cholesterol distribution in the lipoprotein fractions by increasing the ratio of high density lipoprotein (HDL) to very low density + low density lipoprotein (VLDL + LDL) from 0.2 to 0.9. Moreover, it significantly reduced the total liver lipid, thus minimizing the fatty liver formation. In view of the above findings, dietary levels of essential mineral nutrients must be considered in studying the relationship of cholesterol to lipid and lipoprotein metabolism.

Isolation of Metal-Binding Agents from Lettuce Cigarette Smoke and their Effect on O2-Uptake of Liver Slices

Abstract Lettuce leaf cigarettes, a tobacco substitute, were smoked under standardized conditions and the smoke condensate (LSC) was collected. The LSC, amounting to 7.3 mg/cigarette, was fractionated on a carboxy-methylcellulose column in the Cu(II) form, yielding copper-complexing fractions (60% of the total weight) and a noncomplexing fraction (40% of the total). These values are compared to results for tobacco smoke condensate (TSC), which yields about five times as much total solids, of which 25% is in copper-complexing fractions. The ligands from the LSC were found to be inhibitors of O2uptake by rat liver slices, a metalloenzyme requiring system. Thus, the ligands may have adverse effects on cellular energetics.