Splenic rupture during laparoscopy.
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Aged↗
Biomedical subjects
R A Jacob
Publications and source records attributed to R A Jacob.
Automated rate-immunonephelometric determination of serum prealbumin (transthyretin).
We describe an automated determination of serum prealbumin (transthyretin), based on the maximum rate of light scatter of an antigen-antibody precipitate. Optimal dilutions of antibody reagent and of 100-microL serum samples are given. Within- and between-assay CVs are less than 5%. Results by this method are nearly identical with those obtained by a radial-immunodiffusion technique. Measuring the rate of light scatter provides a considerably faster test than equilibrium scatter, electrophoretic, or radial-immunodiffusion methods. Treatment before analysis to clear lipemic sera obviates falsely high results.
Aged↗
Some biochemical indices of nutrition in treated cystic fibrosis patients.
Postprandial levels of copper, ceruloplasmin, iron, total iron binding capacity, cholesterol, vitamin A, carotene, folic acid, vitamin C, albumin, and total globulins in plasma, of 25-OH-vitamin D in serum, and of glutathione reductase activity, an index of riboflavin status, in erythrocytes were determined in a group of 18 juvenile cystic fibrosis patients receiving specialized outpatient care with attention to diet, vitamin supplementation, and pancreatic enzyme replacement. Bone mineralization was assessed by radiographic and photon beam technique. In the plasma of cystic fibrosis patients, levels were elevated for copper, ceruloplasmin, total globins, and total proteins and were depressed for iron, vitamin D, vitamin A, carotene, and albumin. Cortical thickness was diminished in the patients, but bone density was not. For patients with cystic fibrosis, a relation was established between forced vital capacity and certain biochemical indices in plasma. As forced vital capacity decreased, plasma levels increased for copper, total globulins and total proteins and decreased for albumin.
Adolescent↗
Studies on the bioavailability of zinc in humans: effects of heme and nonheme iron on the absorption of zinc.
The change in the concentration of plasma zinc after oral administration of zinc was used as the index of zinc absorption in the study of the interaction of zinc and iron in the human intestine. With zinc sulfate as the source of inorganic zinc, and ferrous sulfate as the source of nonheme iron, a ratio of Fe/Zn of 1:1 slightly inhibited zinc absorption while Fe/Zn ratio of 2:1 and 3:1 substantially inhibited zinc uptake. No effect on zinc absorption was observed, however, when heme iron, as heme chloride, was ingested in a 3:1 Fe/Zn ratio with inorganic zinc. Atlantic oysters providing about 54 mg of zinc were consumed with or without 100 mg of ferrous iron; Fe/Zn ratio was 2:1. With this "organic" form of zinc, iron did not significantly affect zinc absorption. The evidence for competitive interaction of zinc and iron was strongest with nonheme iron and inorganic zinc. Thus, the possibility that intrinsic iron in formulas for feeding infants and in vitamin-mineral supplement might inhibit the absorption of zinc justifies concern about the Fe/Zn ratio in the formulation of these products.
Adult↗
Whole body surface loss of trace metals in normal males.
Whole body surface losses of zinc, copper, and iron were measured in 13 male volunteers who lived in a controlled environment for 4 to 9 months. For 88 daily samples, the mean losses for zinc, copper, and iron were 0.50, 0.34, and 0.33 mg/day (3.9, 26, and 2.1% of the mean dietary intakes, respectively). There was a large variance in metal losses with no significant differences in variance within-versus-between subjects or on the same-versus-different diets. The surface losses of zinc and iron increased the apparent dietary requirements determined by balance measurements only 5 and 3%, respectively, while the increase in copper requirement due to surface loss was 25 to 30%.
Adult↗
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↗
A mathematical model of creatine metabolism in normal males--comparison between theory and experiment.
Based upon knowledge that the body creatine pool in normal males undergoes a constant fractional conversion rate to creatinine and that 24-hr urinary creatinine excretion is dependent upon creatine and protein intakes, we developed a mathematical model with feedback which describes the creatine pool size and, consequently, the 24-hr urinary creatinine excretion as a function of time after change in diet. Validity of the model was tested by comparing calculated with experimental changes in 24-hr urinary creatinine excretion rates of male volunteers who were participating in studies of effects of "high" and "low" protein diets on mineral requirements. The model was further verified by comparing published changes in creatinine excretion rates with changes predicted by the model. It is concluded that the effects of changes in creatine and protein intakes upon the body creatine pool size in healthy males can be described mathematically by a model with a feedback component. It is also cautioned that 24-hr urinary creatinine excretion may not be a good reference for quantifying other urinary substances under circumstances where the creatine or protein intakes are not constant.
Adult↗
An evaluation of trace metals, vitamins, and taste function in anorexia nervosa.
Trace metals, vitamins, and other biochemical parameters were measured in 30 female patients hospitalized for anorexia nervosa with the aim of relating them to taste function, biochemical changes, and clinical signs found in this illness. Plasma zinc (71.9 +/- 14 microgram/100 ml; P < 0.01), urinary zinc (129.5 +/- 121 microgram/24 hr), and copper (84 +/- 17 microgram/100 ml; P < 0.001), were depressed, whereas zinc and copper content of hair was normal. Anorexia nervosa patients showed hypogeusia, with the bitter and sour taste most severely affected, however plasma zinc levels did not correlate with taste recognition scores. Patients showed hypercarotenemia (214 +/- 129 microgram/100 ml; P < 0.01) with normal plasma vitamin A and retinol-binding protein levels. Total iron binding capacity was depressed (261 +/- 62 microgram/100 ml; P < 0.001) in contrast to plasma iron, ceruloplasmin and folic acid, which were normal. In nine patients, who were retested before discharge, taste function improved; plasma zinc, copper, and total iron binding capacity levels increased whereas plasma carotene and cholesterol decreased to normal levels. It is concluded that the observed zinc, copper, and iron binding protein deficiencies, and hypogeusia, reflect the self-imposed nutritional restriction of anorexia nervosa patients. Zinc and other micronutrients released from catabolized tissue along with vitamin intake may mitigate against more severe deficiency states in anorexia nervosa.
Adolescent↗
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↗
Effect of fiber from fruits and vegetables on metabolic responses of human subjects. III. Zinc, copper, and phosphorus balances.
Intakes and excretions of zinc, copper, and phosphorus were determined for 12 men when they consumed a diet low in fiber and when they consumed a diet containing fiber from fruits and vegetables (high-fiber diet). All subjects consumed both diets for 26 days each. The low-fiber diet was supplemented with copper so that it was equivalent to the high-fiber diet in this respect. Mean daily intakes on the low- and high-fiber diets, respectively, were: zinc, 13.2 and 12.6 mg; copper, 1.8 and 1.6 mg; phosphorus, 1.639 and 1.690 g. Mean daily balances on the low- and high-fiber diets, respectively, were: zinc, +3.5 and -0.9 mg; copper, +0.2 and -0.4 mg; phosphorus, +0.361 and +0.292 g. Zinc and copper balances differed significantly on the two diets (P less than 0.001 and P less than 0.005, respectively, but phosphorus balances did not. The fiber supplied by the fruits and vegetables contained more lignin and cellulose and less hemicellulose than would an equivalent amount of fiber from bran. The bran would supply more magnesium, zinc, and copper than this particular diet containing fruits and vegetables.
Adult↗
Studies on the bioavailability of zinc in man. III. Effects of ascorbic acid on zinc absorption.
As ascorbic acid is known to enhance the absorption of dietary iron and to inhibit the absorption of dietary copper, studies were undertaken to examine the effect of ascorbic acid on the bioavailability of zinc in human subjects. The index of absorption was the change in plasma zinc concentration after a 110-mg aqueous dose of ZnSO4.7H2O (containing 25 mg of elemental zinc). Doses of 0.5, 1.0, and 2.0 g of ascorbic acid, representing a spectrum of Zn:ascorbic acid molar ratios from the dietary to the pharmacological range, failed to produce any significant change in the pattern of zinc absorption. Moreover, 2.0 g of ascorbic acid, equivalent to a Zn:ascorbic acid ratio of 0.145 failed to improve the absorption of 108 mg of elemental zinc incorporated into 120 g of black bean gruel. Ascorbic acid over a range of dosages commonly consumed by man had no demonstrable effect on the absorption of inorganic zinc.
Absorption↗
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↗
Abnormal cellular immune responses during acquired zinc deficiency.
The cellular immune response of a 17-year-old decerebrate male with acquired zinc deficiency was studied. He had been fed a commercial formula which contained 7.6 mg zinc per kilogram. His caloric intake had been inadequate as judged by his cachexia. A detailed pretreatment nutritional assessment (five separate observations) which included total serum protein and globulins, albumin, folate, vitamins A, B2, C, ceruloplasmin, and plasma zinc, copper, iron, and total iron binding capacity revealed that the patient was deficient only in zinc and calories. His plasma zinc was 41 +/- 5 microgram/d1 compared with our laboratory norm of 89 +/- 9 microgram/d1 for young adult males. Cellular immunity was assessed by delayed skin reactivity to dinitrochlorobenzene and by in vitro lymphocyte transformation studies. Before zinc therapy the patient rendered a negative skin reaction to dinitrochlorobenzene, and the ability of his lymphocytes to undergo blast transformation in response to mitogen stimulation was significantly depressed with a stimulation index of 4.7 +/- 0.8 as compared with 139.1 +/- 77.3 for controls. Within 3 weeks after zinc therapy (22.7 mg zinc per day) he demonstrated a positive delayed skin reaction to dinitrochlorobenzene and a normal lymphocyte response stimulation index = 205.5 +/- 42.6 versus 199.3 +/- 58.2 for control). In addition, a pretreatment facial seborrhea and a decubitus ulcer rapidly healed.
Adolescent↗
Studies on the bioavailability of zinc in man. Effects of the Guatemalan rural diet and of the iron-fortifying agent, NaFeEDTA.
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Adult↗
Effects of dietary fiber on glucose tolerance of normal men.
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Adult↗
Studies on the bioavailability of zinc in man. II. Absorption of zinc from organic and inorganic sources.
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Adult↗
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↗
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↗