Yosef Dror

Arginase activity in erythrocytes of healthy and ill children

Abstract A quick and reliable method for the determination of blood arginase is proposed. 10 μl of blood are hemolyzed in 0.5 ml Mn2+ and heparin solution. 25 μl of the hemolysate is activated during 20 min at 55° and thereafter incubated with arginine solution for 10 min. The reaction is then terminated by color reagent and the amount of the urea released is read, after boiling for 20 min, at 530 nm. The activity of the arginase in the young red blood cells was found to be 6% higher than in the old cells. The activity of the blood arginase of newborns was found to be 2–3-fold higher than in older children. A higher arginase activity was also found in the blood of patients with megaloblastic anemia.

Lipid oxidation products and chick nutritional encephalopathy

Safflower oil and its distilled methyl esters were thermally oxidized and fed to young chicks in a vitamin E deficient diet. At a dietary level of 10%, the oxidized lipids caused more severe nutritional encephalopathy (NE) than the unoxidized methyl esters, indicating that factors other than dietary linoleic acid and vitamin E affect the development of NE. A polar lipid extract from oxidized methyl esters accelerated the induction of NE, as did the synthetic methyl esters of keto-octadecenoic and keto-octadecadienoic acids. Dicumarol exerted a protective action against NE. The possibility is discussed that conjugated keto-polyenoic fatty acids, provided by oxidized oils or formed endogenously in vitamin E deficiency, may play a role in causing NE.

Hyperhomocysteinemia and vitamin score: correlations with silent brain ischemic lesions and brain atrophy.

Elevated fasting plasma total homocysteine concentration (tHcy) and lower vitamin status are associated with atherosclerotic states. Silent brain ischemic lesions and brain atrophy, prevailing in the elderly, are affected by tHcy and vitamin status. The study was performed on 56 outpatients who had undergone brain computed tomography (CT) before the onset of the study. According to brain CT evaluation, three groups were set: minor brain ischemia, brain atrophy and control. Brain CT, tHcy, plasma pyridoxal phosphate (PLP), vitamin B12, folic acid and cognitive and functional capacities were measured or evaluated in all of the subjects. Plasma vitamin score for three vitamins was calculated. In subjects with minor brain ischemic lesions (n = 21), tHcy was higher by 5.6 µM, whereas vitamin score and cognitive function were lower than in controls (n = 24). In subjects with brain atrophy (n = 11), plasma PLP and cognitive function were lower. Particular attention should be paid to tHcy monitoring, vitamin status assessment and brain impairment evaluation.

Estimation of vitamin needs—riboflavin, vitamin B6 and ascorbic acid-according to blood parameters and functional-cognitive and emotional indices in a selected well-established group of elderly in a home for the aged in Israel.

OBJECTIVE To evaluate the vitamin status and the effects of micronutrient supplementation as determined by biochemical assays and functional, cognitive and emotional tests in a selected well-established group of elderly people, average age above 80 years. METHODS Dietary consumption was evaluated by in-person interview using a food frequency questionnaire. Medical, biochemical, nutritional, functional, cognitive and behavioral parameters were assessed in elderly subjects (n = 12) living in a home for the aged, at baseline and after 42 days of micronutrient supplementation. The same parameters were assessed in additional subjects (n = 9), at baseline only. RESULTS In all subjects, most of the micronutrients were not supplied at an adequate level. Supplementation of micronutrients at a level of 100% RDA improved parameters related to vitamin status, the activation coefficients (AC) of GR (glutathione reductase) and AST, blood ascorbic acid concentrations, functional-cognitive evaluation values, blood pressure, pulse rate, and serum cholesterol and triglycerides levels. At baseline, the following parameters significantly correlated with vitamin intake and were used for the estimation of vitamin needs: AC of GR, Tinetti Balance Evaluation, FIM and recorded morbidity. CONCLUSIONS On the basis of limited available data, calculation of vitamin needs based on regression lines resulted in estimates (mg/day) of: > 150 for ascorbic acid, > 3 for riboflavin, > 3 for vitamin B6. Expanding the current practice of supplementing micronutrients at a level of 100% RDA (in tablet form) that already exists in some elderly societies should be considered after a comprehensive study in a large group of elderly people.

Macronutrient consumption and nutritional status in a selected well-established group of elderly people in a home for the aged in Israel.

OBJECTIVE To evaluate the distribution pattern of the main macronutrients (protein, fat, carbohydrates) and fiber in a selected well-established group of elderly people, average age above 80 years. METHOD Dietary consumption was evaluated in a well-established group of 21 elderly people in a home for the aged by in-person interview using a food frequency questionnaire. RESULTS Daily energy intake was 1.87 Mcal (7.8 MJ) or 29.3 kcal/kg body weight, a value which lies within the range of 1.6 to 2.0 Mcal or 25 to 30 kcal/kg, found in 12 other studies conducted on elderly people. The average percentage of energy derived from macronutrients (with an individual range) was: protein 17.5 (13-22); fat 32.9 (25-44); and carbohydrates 49.6 (35-61). Fiber intake was 8.6 g/Mcal, lower than that found in three other studies. Positive coefficients of correlation were found between protein intake and the following parameters: serum urea (r = 0.28), cholesterol (r = 0.48) and DBP (r = 0.43). CONCLUSIONS In our small group of elderly, energy derived from protein was higher than that in most of other studies reviewed, and that from fat was higher than in half of those studies. These values were remarkably higher than the suggested values. Energy derived from carbohydrates was close to that found in other studies. Monitoring of dietary macronutrients might improve the nutritional and the physiological status of the elderly.

Absorption of macro- and micro-elements by sheep from barley and barley plus sulphur dioxide-treated straw rations

Abstract Sheep cannulated in the rumen, duodenum and ileum were used to study absorption of minerals from diets: I. barley only (B), and II. 70% (DM basis) barley + 30% SO2 treated wheat straw (B+S). Na and K were highly absorbed from both diets and almost completely recovered in the urine. Ca apparent absorption was low: 12.1% and 13.4% in the B and B+S treatments, respectively. The Mg net absorption in the rumen was significantly higher in diet B than in diet B+S; the difference in total tract apparent absorption of Mg was, however, much smaller and not significant: 44.5% and 38.2% for the B and B+S treatments, respectively. Animal variation in P absorption was very large, ranging from 5% to 66%. There was a trend toward net secretion of Cu, Zn and Mn in the stomachs, the trend being 2–3 times higher in the B+S than B diet. Generally, the apparent absorption of Cu, Zn and Mn was lower in the B+S than B diet; however, the most notable difference was with Cu absorption.

The Impact of Refeeding on Blood Fatty Acids and Amino Acid Profiles in Elderly Patients: A Metabolomic Analysis

BACKGROUND Refeeding of elderly frail patients after food deprivation is commonly associated with a high mortality rate. OBJECTIVE To evaluate the effect of refeeding on metabolite fluctuation of blood carnitine fatty acids (15 compounds) and free amino acids (14 compounds). METHODS Metabolite fluctuation was followed up in an exploratory, cohort, and noninterventional study in elderly and frail patients (84.5 ± 5 years) after a long period of food deprivation. Patients in the study group were refed by enteral nutrition (EN) and were followed up during 7 days for blood metabolites (n = 27). Patients in the control group (n = 26) had been fed by EN for more than 3 months. Refeeding was initiated with 10 kcal/kg/d and gradual increases of 200 kcal/d for 3 days afterwards. Blood metabolites were assayed in a sample of 25 µL. RESULTS On food deprivation, the concentrations of all even monocarboxylic carnitine fatty acids were much higher in the study group than in the EN control group (P < .01). Upon refeeding, a remarkable decrease in all carnitine fatty acids was observed. In addition, significant daily fluctuations were observed for most metabolites in the study group of the refed patients as compared with the EN control group (P < .01). The highest fluctuations were observed following refeeding in the 7 patients who later died. CONCLUSION A significant metabolic instability is observed on refeeding even with a slow refeeding schedule of 10 kcal/kg/d. Measurement of metabolomics parameters may be used for the evaluation of malnutrition, refeeding status, and optimization of the enteral formula.

Modeling and analysis of bleaching processes in photo-excited chlorophyll solutions

Photo-bleaching phenomena occurring in chlorophyll-a (Chl-a) during irradiation with UV spectra sources were investigated. A general mathematical formalism was developed to quantify the chromophores spatio-temporal concentration in the irradiated solutions. The measured changes of the optical transmission in photo-excited solutions were used to evaluate the chromophores bleaching reaction rate. An empirical expression for the reaction rate is sought and combined with the mathematical model to characterize the bleaching properties of the chlorophyll solutions and their optical density recovery by diffusion after the irradiation.

Turnover of short-lived proteins in chick leukocytes following dietary treatments

The effect of protein intake (10 vs. 20%) on synthesis and degradation of short-lived leukocyte proteins in vitro was shown in 21-day-old chicks. Protein synthesis was measured for 1 or 2 h and protein degradation for 1.5 or 4 h following an 8-day dietary treatment. Leukocyte proteins were fractionated on a slab gel into 11 or 100 fractions, and the imaging radioactivity was calculated for protein synthesis and degradation. The degradation rates in most of the protein fractions were higher in the leukocytes of chicks fed 20% dietary protein than in those fed 10% protein. Protein fractions of M(r) approximately 25-37 kD exhibited the most marked differences between the two dietary treatments. This technique of measuring turnover rates of short-lived proteins in leukocytes could potentially be used to examine the effect of nutritional treatments in animals and man as well as to check the effect of catabolic conditions in humans on protein turnover.

Lysosomal acid phosphatase decrease in nutritional encephalopathy in chicks.

Encephalopathy was induced in 14-day-old chicks by a vitamin E-deficient diet containing 15% thermally oxidized safflower oil. Bound acid phosphatase activity in the cerebellum was markedly lower in affected chicks than in vitamin E-supplied control chicks. Free activity also tended to be lower in the deficient group. There were no differences in enzyme activities of cerebrum and liver between deficient and control chicks.