Effect of alpha-tocopherol on the respiratory burst of neutrophils, blast transformation of lymphocytes, and activity of human natural killer cells in blood

The effect of vitamin E on immunological reactions of blood cells was studied. The addition of vitamin E in concentration of 100 microM to neutrophils caused the increase of superoxide production. But this index was decreased when incubation of these cells with A23187 or FMLP was accompanied by alpha-tocopherol in concentration of 100 microM followed by the removal of free ligand or alpha-tocopherol in concentration of 0.5 microM. In the presence of PMA the inhibiting action of alpha-tocopherol was not found (under the 0.5 microM of alpha-tocopherol) or was small (under the concentration of it 100 microM of alpha-tocopherol). The addition of alpha-tocopherol in concentration of 0.5 microM and 50 microM caused the inhibition of blasttransformation of lymphocytes and activity of natural killer cells. This effect was expressed more under the low contents of this vitamin in the incubation medium. The level of blasstransformation of blood in vitamin E-deficient rats was by 20% less than in normal. The exogenous addition of alpha-tocopherol in concentration of 0.5 microM did not affect this value. It was suggested that vitamin E can affect the respiration burst of neutrophils, blasttransformation of lymphocytes and activity of natural killer cells and these actions depend on its concentrations.     

Serum beta-carotene and antioxidant micronutrients in children with cancer. The 'Cancer in Children and Antioxidant Micronutrients' French Study Group

Serum antioxidant vitamins A (retinol) and E (alpha-tocopherol), beta-carotene, zinc and selenium for 418 children with newly diagnosed malignancy were compared with those of 632 cancer-free controls. Incident cancer cases and controls were 1-16 years old and recruited in 1986-1989. Age- and sex-adjusted serum concentrations of retinol, beta-carotene and alpha-tocopherol were significantly inversely associated with cancer. In similar models, the odds ratio (OR) comparing the highest with the lowest quintile was 2.06 (95% confidence interval [CI] 1.40-3.02) for retinol, 3.87 (95% CI: 2.54-5.90) for beta-carotene, 2.15 (95% CI: 1.48-3.10) for alpha-tocopherol, 1.29 (95% CI: 0.75-2.23) for selenium, and 1.94 (95% CI: 1.17-2.23) for zinc. The cancer sites that were associated with serum beta-carotene were, in general, leukaemia, lymphoma, central nervous system, bone and renal tumours. Moreover, leukaemia was associated with low mean serum levels of retinol, selenium and zinc. Subjects with lymphoma, bone and renal tumours also had lower mean retinol and alpha-tocopherol levels than controls. Brain tumour patients had low vitamin E levels. Low serum values of antioxidant vitamins were associated with childhood neoplasm occurrence. Some site-specific effect was reported. Low peripheral nutrient levels are not considered as cancer promoters but rather as an impairment of the body's defence mechanism occurring during the cancer-related metabolic and nutritional disturbances and inflammation processes.     

Fish oils lower rat plasma and hepatic, but not immune cell alpha-tocopherol concentration

These studies were designed to measure the impact of different fish oil sources of dietary (n-3) polyunsaturated fatty acid on the alpha-tocopherol content of rat immune cells. In the first experiment, rats were fed diets containing either lard, corn oil, menhaden fish oil or cod liver oil. In the second study, sardine fish oil replaced corn oil. Dietary fat source did not significantly influence body weights or the yield of immune cells in either study. In both studies, plasma and liver alpha-tocopherol concentrations were significantly lower in (n-3) polyunsaturated fatty acid-fed rats than in rats fed lard. In the first study, immune cell alpha-tocopherol concentrations followed those observed in the plasma and liver. These concentrations closely paralleled the amount of RRR-alpha-tocopheryl acetate added to diets and not the total vitamin E present, which was the same for all treatment groups. However, in the second study, alpha-tocopherol concentration of immune cells was not significantly different among rats fed lard, menhaden fish oil, and sardine fish oil. In that study both the amount and form of vitamin E were carefully balanced across dietary treatment groups. In conclusion, despite having similar amounts of (n-3) polyunsaturated fatty acids, two out of three fish oils tested did not lower immune cell alpha-tocopherol concentration even in the face of significantly reduced plasma and liver alpha-tocopherol concentrations.     

Increased apoptosis of adult rat lymphocytes after single neonatal vitamin A treatment (hormonal imprinting). A flow cytometric analysis

Newborn rats were treated with a single dose of vitamin A (retinol) and apoptosis of peripheral lymphocytes was studied by flow cytometry in adult age. Vitamin A treatment (hormonal imprinting) caused a moderate, however significant elevation in the number of apoptotic lymphocytes after three months. Dexamethasone or Concanavalin-A alone did not influence apoptosis significantly. However, in the neonatally retinol treated rats dexamathasone significantly elevated the quantity of apoptotic lymphocytes related to the control or Concanavalin-A treated control cells. The results call attention to the prolonged effect of hormonal imprinting in a new index and to the possible dangerous effects in human, neonatally treated with vitamin A.     

Methods for determination of vitamins A and E our simple HPLC assay

Biological effects of reactive oxygen species and other radicals which are controlled by antioxidant mechanism are exerted on the basis of enzymes and substrates. Antioxidant substrates are divided into lipophilic and hydrophilic groups. Main representants of lipophilic antioxidants are retinol and tocopherol which are closely related to ascorbate in the hydrophilic compartment. Described methods for detection of retinol and alpha-tocopherol are simple, sensitive, specific and precise. They are reliable, economic and fast. Only small amounts of serum are used for one analysis which is convenient for patients, too. Our methods can be recommended for routine use in laboratories of clinical biochemistry. Haemodialyzed patients, retinol serum level was higher than that in blood donors while alpha-tocopherol serum level did not differ. Both vitamin A and E serum levels were similar in alcoholics compared to controls.     

A routine method for the simultaneous measurement of retinol, alpha-tocopherol and five carotenoids in human plasma by reverse phase HPLC

We describe a simple isocratic HPLC method for the accurate and precise measurement of retinol, alpha-tocopherol and the major carotenoids in plasma using UV detection. Reference ranges for retinol, alpha-tocopherol and five carotenoids are determined in a healthy population group. The most abundant carotenoids found in plasma were beta-carotene, lycopene, lutein and cryptoxanthin. Retinol, alpha-tocopherol and carotenoids were determined simultaneously using two internal standards, retinol acetate for retinol and tocopherol acetate for alpha-tocopherol and carotenoids. The use of echinenone as an internal standard for carotenoids was investigated. The protective effect of an antioxidant (ascorbic acid) on the stability of samples and extracted material is documented. The method is useful for the routine measurement of plasma retinol, alpha-tocopherol and carotenoids and could also be used in large scale epidemiological studies.     

Delaying colostrum intake by one day impairs plasma lipid, essential fatty acid, carotene, retinol and alpha-tocopherol status in neonatal calves

To study whether a delayed start of colostrum feeding in calves affects plasma lipids, fatty acids and fat-soluble vitamins, one group was fed colostrum (milkings 1-4) on d 1 and 2, then mature milk up to d 7, whereas two other groups were fed glucose or water on d 1, colostrum (milkings 1-4) on d 2 and 3 and then mature milk up to d 7. In calves fed colostrum on d 1, starting 5-7 h after birth, plasma concentrations of triglycerides, phospholipids, total cholesterol and of essential and nonessential fatty acids in triglyceride, phospholipid and cholesterol ester fractions as well as of carotene, retinol and alpha-tocopherol up to d 7 were significantly higher than in calves in which colostrum feeding started after >24 h of life. On the other hand, plasma concentrations of vitamin B-6, vitamin B-12 and folic acid were not influenced. Results indicated reduced efficiency of absorption of colostral fatty acids and of fat-soluble vitamins, but not of (selected) water-soluble vitamins, if colostrum is not fed on d 1 of life. In conclusion, colostrum intake within the first 24 h of life is required for an adequate plasma lipid, essential fatty acid, carotene, retinol and alpha-tocopherol status in the first week of life of calves.     

Surgical treatment of chronic pulmonary thromboembolism

It has become increasingly obvious that free radicals and lipid peroxidation contribute to brain damage from trauma by mediating edema formation and ischemia. It should, therefore, be expected that the actual level of endogenous antioxidants, as for example, vitamin C and E in plasma, has an influence on the extent of free radical-induced injury. In this communication we investigate the effect of dietary changes in the free radical scavenger alpha-tocopherol on posttraumatic cerebral swelling in Sprague-Dawley rats. Low, normal, and high plasma levels of alpha-tocopherol were established by respective diets supplied over 2 weeks. Animals of all groups received the same food without alpha-tocopherol. One group was fed a vitamin E-free diet. The pellet-food for the other animals was supplemented either with 5-mg alpha-tocopherol/100 g or 250-mg alpha-tocopherol/100 g dry mass, respectively. The vitamin E-free diet lowered the alpha-tocopherol level in plasma to 30% of control, whereas supplementation with 250 mg/100 g led to a plasma concentration of 200% of control. The animals were then subjected to a focal cold injury of the left cerebral hemisphere. Twenty-four hours after trauma the brain was removed and the water content of each hemisphere was determined by the wet-dry weight method. Swelling of the traumatized hemisphere was calculated as the difference in weight between the traumatized and contralateral control hemisphere. The 2-week alpha-tocopherol supplementation or -deletion diet, respectively, did not either afford significant reduction or lead to an enhancement of traumatic brain swelling. Likewise, the increase in brain water content of the traumatized hemisphere was not affected. It is concluded that supplementation or depletion of alpha-tocopherol for 2 weeks, resulting in a marked increase or decrease of the vitamin E plasma level, does not influence formation of posttraumatic vasogenic brain edema.     

Effect of insecticides on vital activity, hepatic enzymes and red blood cell acetyl cholinesterase activity of rabbits in Makkah

Vitamin E is important in maintaining normal neurological structure and function. In this study, 100 children with protein-energy malnutrition (PEM) were studied and compared to a suitably age-matched control group. Posterior column deficits, cerebellar deficits, and problems with fine motor coordination were present to a significant degree in the PEM subjects. The presence of neurological signs was correlated with various parameters of vitamin E deficiency, including low serum alpha-tocopherol levels and a low tocopherol/total lipid ratio which was present in 92 per cent of subjects. There was good concordance between vitamin E levels and vitamin E to serum lipid ratio in assessing vitamin E deficiency. We conclude that vitamin E deficiency is prevalent, to a hitherto unsuspected degree, in children with PEM and that these malnourished children have significant neurological deficits attributable to low vitamin E levels. This observation is of clinical significance as the neurological deficits are potentially reversible with vitamin E supplementation.     

The effect of alpha-tocopherol and beta-carotene supplementation on COPD symptoms

The effects of alpha-tocopherol (50 mg/d) and beta-carotene (20 mg/d) supplementation on symptoms of chronic obstructive pulmonary disease were studied among the 29,133 participants of the Alpha-Tocopherol Beta-Carotene Cancer Prevention Study undertaken to investigate the effects of these two substances in the prevention of lung and other cancers. During the follow-up the supplementations did not affect the recurrence or incidence of chronic cough, phlegm, or dyspnea. The prevalence of chronic bronchitis and dyspnea at baseline was lower among those with high dietary intake of beta-carotene (OR = 0.78 and 0.67, respectively) or vitamin E (OR = 0.87 and 0.77) and high serum beta-carotene (OR = 0.59 and 0.62) and alpha-tocopherol (OR = 0.76 and 0.82). High intake and serum levels of retinol were associated with low prevalence of dyspnea (OR = 0.84 and 0.80, respectively) but not with chronic bronchitis. The results indicate no benefit from supplementation with alpha-tocopherol or beta-carotene on the symptoms of chronic obstructive pulmonary disorders but support the beneficial effect of dietary intake of fruits and vegetables rich in these compounds.     

Effect of 2,3,7,8-tetrachlorodibenzo-p-dioxin on the lymphatic absorption of a single oral dose of [3H]retinol and on the intestinal retinol esterification in the rat

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) alters the turnover of vitamin A in the body and inhibits the normal hepatic accumulation of dietary vitamin A. Vitamin A is absorbed in the small intestine, where it is incorporated into chylomicrons as retinyl esters for release into the lymph and further distributed via blood to the liver for storage. The aim of the present study was to investigate if the decreased hepatic vitamin A levels in TCDD-exposed rats could be due to impaired intestinal absorption of vitamin A via lymph. Male Sprague-Dawley rats were given a single oral dose of TCDD (10 microg/kg). Five days after administration, the main intestinal lymph duct of the rats was cannulated. After a 24-h recovery from surgery, the rats were each given a single dose of [3H]retinol in corn oil via gavage and the lymph was collected for 24 h. The cumulative radiolabel recovered in the intestinal lymph was significantly lower in TCDD-treated than in control rats during the first 6 h of absorption. However, no significant differences in radiolabel recovered in lymph were seen when looking at the entire 24-h collection period. In the intestinal mucosa, retinol esterification catalyzed by the enzyme lecithin:retinol acyl transferase (LRAT) or acyl coenzyme A (CoA):retinol transferase (ARAT) was not statistically different between the groups. However, mucosal retinyl palmitate levels were significantly increased in TCDD-treated rats. In conclusion, a small and transient reduction was found of the uptake of vitamin A into the lymph of TCDD-treated rats. It is obvious that this finding cannot explain the TCDD-induced decrease in hepatic vitamin A levels in the rat. Rather, a combination of inhibited retinol esterification in hepatic stellate cells, increased release of endogenous vitamin A, and increased hepatic catabolism of retinoids could explain the effect of TCDD on liver retinoid levels.     

Effects of zinc and vitamin A deficient diets on the hepatic mobilization and urinary excretion of vitamin A in rats

Weanling rats were fed diets deficient in zinc (ZD), vitamin A (AD), or both (ZAD) for 3 weeks. Each then received 20 mug of 11,12-3H-retinyl acetate. Plasma retinol was monitored for radioactivity for 5 hours and urine for 6 days. Rats were killed and measurements made of plasma and liver vitamin A and plasma zinc. Plasma vitamin A was depressed but growth was not affected in AD rats compared to pair-fed controls. Radioactivity appeared most rapidly in the plasma retinol fractions of the two vitamin A-depleted groups (AD and ZAD) and was excreted most rapidly in the urine of these same groups. Zinc-deficient diets (ZD and ZAD) caused depressed plasma levels of zinc and vitamin A and growth retardation greater than in pair-fed controls. However zinc deficiency had no effect on mobilization of newly-ingested vitamin A or urinary excretion of labeled metabolites. Liver stores of vitamin A were lower for ZD rats than for controls. The data indicate that zinc deficiency is not a limiting factor in hepatic vitamin A release except as it influences growth and body demand for the vitamin. The data also suggest that newly-absorbed vitamin A is mobilized and utilized in preference to that previously stored in the liver.     

Comparison of the postprandial plasma vitamin A response in young and older adults

To assess the influence of age on vitamin A intestinal and liver metabolism in humans, the postprandial plasma concentrations of intestinal-originated vitamin A, i.e., retinyl esters, and liver-originated vitamin A, i.e., retinol, were compared in eight young (20-30 years old) and eight elderly (64-72 years old) healthy men. Plasma and chylomicron retinyl esters and retinol concentrations were measured for up to 24 h following the intake of a test meal that contained 23,300 RE retinyl palmitate. The chylomicron retinyl palmitate response (area under the curve) was not significantly different between the two groups, but its peak was slightly delayed (1 h) in the elderly men. The proportion of the different retinyl esters secreted in the chylomicrons was not significantly different between the two groups. The postprandial plasma retinol concentration did not change in the young participants, whereas it significantly increased in the elderly. These results suggest that vitamin A intestinal absorption and retinol intestinal esterification processes are not markedly modified in the elderly, whereas the chylomicron clearance and the regulation of postprandial plasma retinol concentration are apparently altered in these subjects.     

Predictors of serum retinol in children with shigellosis

BACKGROUND: Low serum retinol can be useful as an indicator of depleted liver vitamin A stores, particularly in population-based studies. However, serum retinol concentrations decrease transiently during infection, independent of any changes in liver stores. The magnitude of the decrease in serum retinol is often proportional to indicators of disease severity. OBJECTIVE: We examined the relation of serum retinol in children with culture-positive shigellosis with severity of illness, anthropometric indicators of nutritional status, urinary retinol excretion, and serum concentrations of C-reactive protein, alpha1-acid glycoprotein, retinol binding protein, and transthyretin. DESIGN: This was a prospective study assessing the clinical and laboratory measurements at admission and recovery of 90 children with dysentery (66 with shigellosis) hospitalized in Bangladesh. RESULTS: Serum retinol concentrations were low at admission but were significantly greater at discharge even though no vitamin A supplements were given during the illness (0.36 +/- 0.22 compared with 1.15 +/- 0.50 micromol/L, P < 0.001). Serum retinol concentrations were lower in children with Shigella dysenteriae type 1 infection than in children with shigellosis due to less virulent strains of Shigella. Low serum retinol was independently associated with S. dysenteriae type 1, high serum C-reactive protein concentrations, and low weight-forage in multiple regression analysis. CONCLUSIONS: This study showed that shigellosis was associated with a significant, transient decrease in serum retinol concentrations of approximately 0.8 micromol/L, and that this change was significantly associated with severity of disease and poor underlying nutritional status, particularly low weight-for-age.     

Plasma and erythrocyte alpha-tocopherol and plasma retinol concentrations in term infants fed formula enriched with long-chain polyunsaturated fatty acids

OBJECTIVE: To assess the effect of long-chain polyunsaturated fatty acids (LCPUFA)- and vitamin E-supplemented formula feeding on erythrocyte and plasma alpha-tocopherol (VE), and plasma retinol (VA) concentrations in neonates and to compare these values with those found in infants feeding on infant formula without LCPUFA or breast milk SETTING: University Hospital of Granada, Spain. SUBJECTS: 49 full-term infants. DESIGN AND INTERVENTION: Subjects who chose not to breast feed were fed either (i) unsupplemented infant formula (F) or (ii) infant formula supplemented with LCPUFA and vitamin E (FL). Alpha-tocopherol and retinol were measured at 7 days, 1 month and 3 months. RESULTS: Plasma and erythrocyte VE concentrations and plasma VE/total lipids ratio increased significantly in all groups at 1 month of life (P < 0.05), but did not change significantly between 1 month and 3 months in any group (P > 0.05). Erythrocyte VE and VA retinol concentrations were higher in infants fed an infant formula than in breast milk-fed infants at 1 month of life (P < 0.05). Finally, there were no significant differences in plasma or erythrocyte VE levels, plasma VA or plasma VE/total lipid ratio between any groups at 3 months of life (P > 0.05). CONCLUSION: Infants fed on LCPUFA- and vitamin E-supplemented infant formula for 3 months have similar vitamin E and A status to infants fed on breast milk or infant formula without LCPUFA supplementation.     

Effect of improved vitamin A status on response to iron supplementation in Pakistani infants

We report an apparently protective effect of vitamin A in infants who received iron supplements (15 mg/d) for 3 mo. Those receiving iron showed increases in hemoglobin (8 g/L), ferritin (3.7 micrograms/L), and the acute-phase protein alpha 1-antichymotrypsin (ACT; 0.06 g/L). In both the placebo and iron-supplemented groups there were increases in plasma retinol, lutein, alpha-tocopherol, immunoglobulin A, and immunoglobulin G. The improvement in vitamin A status could only have been from a seasonal increase in dietary sources of vitamin A, eg, breast milk and early weaning foods, and there were no obvious effects on iron utilization (hemoglobin concentrations). However, in the infants receiving iron, those whose retinol concentrations increased also showed reductions in ACT, ferritin, immunoglobulin A, and immunoglobulin M. Vitamin A is well known for its antiinfective properties and we suggest that these observations illustrate the importance of even small increases in dietary vitamin A or differences in vitamin A status in reducing the potentially toxic effects of iron supplements in persons in developing countries. These conclusions should now be confirmed with an intervention study to show that the benefits of vitamin A on iron status are due to reduced levels of infection.     

Up-regulation of nuclear PP1alpha and PP1delta in hepatoma cells

BACKGROUND: Although most previous studies have attempted to correlate plasma concentrations of vitamins with specific cardiovascular end points, metabolic considerations suggest that changes in myocardial tissue and storage organs may be better indicators of myocardial oxidative stress. METHODS AND RESULTS: Rats fed commercial chow or a diet enriched with vitamin E for 2 weeks were subjected to either a surgical myocardial infarction (MI) or a sham procedure. Rats were hemodynamically assessed 16 weeks after surgery, and their heart, liver, kidney, and plasma were analyzed for antioxidant vitamins E (tocopherol) and A (retinol and total retinyl esters). At 16 weeks, MI rats on a control diet showed depressed peak systolic and elevated diastolic pressures in both right and left ventricles compared with their sham controls. Plasma concentrations of vitamins E and A in MI rats were not different from sham controls fed the same diet. However, concentrations of vitamin E in left ventricle and liver and of vitamin A in liver (retinol) and kidney (retinyl esters) were decreased in rats with MI compared with the sham controls. Vitamin E supplementation improved hemodynamic function in rats with MI and increased plasma, myocardial, liver, and kidney concentrations of vitamin E. The vitamin E diet also prevented the loss of total retinyl esters from the kidney but not of retinol from the liver in MI rats. CONCLUSIONS: Dietary supplements of vitamin E can sustain better cardiac function subsequent to MI. Antioxidant vitamin levels in the myocardium or in storage organs and not in plasma may be better indicators of myocardial oxidative stress.     

Blood vitamins, mineral elements and inflammation markers as risk factors of vascular and non-vascular disease mortality in an elderly population

BACKGROUND: The need for protecting agents against degenerative processes of the body has been proposed to be especially high in elderly people. In order to evaluate the prognostic value of various biochemical factors in ageing the associations of blood concentrations of several vitamins, mineral elements and some other suggested risk factors with vascular and non-vascular mortality were studied in an elderly population. METHODS: A large health survey with complete clinical evaluation was carried out in the City of Turku in 1982-1983. A random sample of 344 community-living elderly individuals aged 65 years or older, stratified into four age groups, was studied. During the 13 years follow-up 225 subjects had died. Calcium, magnesium, copper, ceruloplasmin, zinc, selenium, iron, ferritin, transferrin, alpha-tocopherol, retinol, folate, vitamin B12, malondialdehyde, orosomucoid and insulin levels were analysed from the blood specimens. The relations between the compounds measured and relative mortality risks during the 13-year follow-up were analysed by Cox proportional hazards model adjusting for other known risk factors. RESULTS AND CONCLUSIONS: High concentrations of serum copper, orosomucoid and insulin were associated with increased risk of vascular mortality. The relative risks within the subjects of the highest tertile of serum concentrations were 2.2 for copper, 1.8 for orosomucoid, and 1.8 for insulin when adjusted for many confounding risk factors. Low serum vitamin B12 concentrations appeared to be significantly (P = 0.01) associated with increased vascular mortality. The associations were essentially not more significant when adjusted only for age. Contrary to earlier observations concentrations of serum magnesium, selenium, alpha-tocopherol, iron and its binding proteins or plasma and erythrocyte folate were not associated with increased mortality risk when adjusted for confounding risk factors. The authors suggest that in elderly subjects these elements and compounds are at the most weak, and probably non-independent risk factors for vascular mortality.     

Uptake, tissue distribution, and depuration of cadmium (Cd) in the frog Rana ridibunda

Two studies were conducted to investigate whether vitamin A-deficient rats were more susceptible to intestinal injury caused by methotrexate (MTX), since vitamin A deficiency alone causes only mild changes to jejunal structure and function. Weanling male rats were fed a vitamin A-deficient diet (-VA) for 40-42 d and compared to rats either pair-fed (PF) or with free access (+VA) to the same diet. Drinking water of PF and +VA rats was supplemented with 37.5 microg (Study 1) or 75 microg (Study 2) vitamin A (Rovimix A 500W)/d. Rats in each group received MTX (-VAMTX, PFMTX, +VAMTX) or vehicle. MTX administration reduced intestinal mucosal wet weight, protein and DNA concentrations, and sucrase and maltase activities in -VA and PF rats (P < 0.02). In Study 1, -VAMTX rats developed a severe jejunal enteropathy and had a higher incidence of diarrhea (P < 0.005), greater weight loss (P < 0.005), more disruption of villus architecture (P < 0.0001) and lower disaccharidase activity (P < 0.007) than PFMTX rats. Similar results were observed in Study 2. Liver retinol concentration (but no other variable) was greater in rats receiving 75 microg vitamin A/d (P < 0.001) than in those receiving 37.5 microg/d. The interaction of vitamin A deficiency and small intestinal injury may explain the efficacy of vitamin A supplementation in preventing childhood diarrheal disease mortality in developing countries, and highlights the need for ensuring adequate vitamin A status in people worldwide with diseases and/or treatments which may injure the gastrointestinal tract.     

SCH 43478 and analogs: in vitro activity and in vivo efficacy of novel agents for herpesvirus type 2

Previous surveys have suggested that preschool children in the North and Northeast of Thailand are at risk of inadequate vitamin A nutriture. Therefore, vitamin A status was assessed in 996 children aged 2-6 years in the North and Northeast Thailand during the dry (Feb.-April) and rainy (Sept.-Nov.) seasons. Approximately 1 per cent of samples during both periods exhibited serum retinol concentrations below 10 mcg/dl with means (+/-SD) concentration of 29 +/- 9.8 mcg/dl in the dry season and 37 +/- 15.4 mcg/dl in the rainy season. About one fifth of the studied children showed abnormal CIC and depleted liver stores (RDR > 20%). High risk areas were ranked and corresponded well by these 2 indicators. Therefore, it is concluded that the magnitude of the problem estimated by RDR and CIC are a more precise measurement of marginal vitamin A status than serum vitamin A level alone and about one-fifth of preschool children in the North and Northeast regions of Thailand experience subclinical vitamin A deficiency.