Medical uses of vitamin E

Bioavailability of intramuscular vitamin E acetate in rabbits

The bioavailability of alpha-tocopherol acetate and alpha-tocopherol (vitamin E) was assessed in male rabbits given 50 mg kg-1 doses according to a randomized design. After intramuscular injection of alpha-tocopherol acetate in colloidal aqueous solution, a mean absolute bioavailability of 65% was calculated for the acetate and 35% for the physiologically active compound, alpha-tocopherol. Comparison of the kinetic profiles after intravenous and intramuscular administration of the acetate and intravenous injection of alpha-tocopherol, revealed absorption of alpha-tocopherol acetate from the site of injection and hydrolysis of the acetate to be potential limiting steps in the bioavailability of alpha-tocopherol. Intramuscularly injected alpha-tocopherol acetate in olive oil (the only formulation available in a few European countries) proved completely bio-unavailable. It thus appears necessary to re-assess the utility of current vitamin E supplementation, since the only formulations available offer poor bioavailability.

Plasma vitamin E, apolipoprotein B and HDL-cholesterol in middle-aged men from southern Italy

Plasma vitamin E, HDL-cholesterol, apolipoprotein B and triglycerides were measured in an apparently healthy, male, random population sample (n = 74) from Southern Italy. Plasma vitamin E concentration was positively correlated to that of serum cholesterol, non-HDL cholesterol, triglycerides and apolipoprotein B (all P less than 0.001). The results of partial correlation analysis showed that apo B, the apolipoprotein constituent of LDL, was related to vitamin E independently of serum triglycerides, a fairly accurate marker of VLDL. On the other hand, triglycerides were related to vitamin E independently of apo B. Both correlations were much weaker if an adjustment was performed for non-HDL-cholesterol. No independent relationship was demonstrated between plasma vitamin E and HDL-cholesterol.

Alagille syndrome associated with moyamoya disease

A 22-month-old girl with the typical manifestations of Alagille syndrome presented with acute right hemiparesis. Cerebral angiographic studies demonstrated the presence of complete occlusion of both internal carotid arteries with the formation of a collateral network of vessels compatible with the diagnosis of Moyamoya disease. This rare association has not been reported previously.

Differences in tocopherol-lipid ratios in ARDS and non-ARDS patients

Plasma tocopherol, plasma total lipid levels and tocopherol-lipid ratio were measured every 6 h during 48 h in 12 critically ill patients and compared with those of a control group. The patients were divided into two groups. Group I comprised 6 critically ill patients with ARDS and group II comprised 6 severely ill patients without ARDS. The means for all observations of plasma tocopherol, total lipid levels and tocopherol-lipid ratio in groups I and II were significantly depressed relative to a control group (p less than 0.0001). The difference in the average tocopherol-lipid ratio between the three groups (p less than 0.0001) and between the groups I and II was statistically significant (p less than 0.0001). Our results indicated: (1) a decrease of vitamin E concentrations in the critically ill patients, particularly in ARDS patients; (2) the importance of the relationship between plasma tocopherol and plasma lipids levels in evaluating the deficiency in vitamin E which was evident in ARDS patients.

Levels of vitamin A and cellular retinol binding protein in human hepatocellular carcinoma and adjacent normal tissue

The levels of vitamin A (retinol) and vitamin E were measured in the blood, in tissues of human hepatocellular carcinoma (HCC), and in adjacent liver parenchyma. The median values of vitamin A were 11.5 micrograms/g (ranging 0-82.5 micrograms/g) in HCC and 52.1 micrograms/g (ranging 0.4-895.2 micrograms/g) in normal liver tissues; the difference was statistically significant (p less than 0.05). By contrast, there was no significant difference in vitamin E levels between the two tissues. Although the levels of vitamin A were significantly lower in HCC in 10 patients, no significant difference was noted in the cellular retinol binding protein levels in the normal and malignant tissues. These results suggest that the decreased levels of vitamin A in HCC are not due to altered cellular retinol binding protein levels in tumors and the different vitamin A blood supply system. We conclude that either the decreased uptake of vitamin A, but not vitamin E, by HCC cells or the lack of vitamin A-storing cells in tumors might be responsible for the low levels of vitamin A in HCC.

Serum vitamin E, serum selenium and the risk of gastrointestinal cancer

The association between levels of alpha-tocopherol and selenium in serum and subsequent risk of gastrointestinal cancer was investigated in a longitudinal study based on 36,265 Finnish men and women, aged 15-99 and initially free of cancer. Serum alpha-tocopherol and serum selenium levels at entry into the study were measured from stored serum samples of 150 incident gastrointestinal cancer cases diagnosed during a follow-up of 6-10 years and for 276 controls who were matched for sex, age and place of residence. Subjects with a low level of alpha-tocopherol or selenium had an elevated subsequent risk of cancer of the upper gastrointestinal tract. This association persisted among men after adjustment for various confounding factors and after the exclusion of those with cancer diagnosed during the first 2 years of follow-up. The relative risk of cancer of the upper gastrointestinal tract among men who fell in the lowest quintile of serum selenium was 3.3 (95% confidence limits, 1.3 and 9.1) while among those who fell in the 3 lowest quintiles of alpha-tocopherol it was 2.2 (95% confidence limits 0.9 and 5.6) compared with those in the higher quintiles. Serum levels of selenium or alpha-tocopherol in general were not inversely associated with colorectal cancer risk. These findings indicate that high selenium intake and possibly also high vitamin E intake, especially among men, may provide protection against cancer of the upper gastrointestinal tract but not against colorectal cancer.

Determinants of serum alpha-tocopherol in Finnish adults

The relationship between serum alpha-tocopherol level and many of its possible determinants was studied in 1,373 cancer-free Finnish men and women age 40-79 years. Dietary data were available from a subsample of 301 persons. The mean alpha-tocopherol level in the serum samples stored at -20 degrees C was 8.6 mg/liter among men and 10.5 mg/liter among women. Intake of margarine, vegetable oils, and green vegetables predicted the serum level of alpha-tocopherol. Altogether six food groups accounted for about 10% of the variation. The levels also varied with age, geographical area, type of population, occupation, socioeconomic status, and marital status. They were positively correlated with serum cholesterol and serum vitamin A in both sexes, and with body mass index and serum selenium in men. Altogether these variables accounted for over 40% of the variation in alpha-tocopherol levels. The level of serum alpha-tocopherol, which is associated with the dietary intake of vitamin E, is dependent upon living conditions.

Chromatography of fat-soluble vitamins in clinical chemistry

A review is presented of current gas and liquid chromatographic methods for the determination of the fat-soluble vitamins A, D, E and K and the provitamin A beta-carotene in biological samples of human origin. For each vitamin, the discussion successively focuses on procedures for sample preparation, gas and liquid chromatographic systems and principles of detection. The emphasis is on liquid chromatography, which is gradually becoming a standard technique in fat-soluble vitamin assays. New trends in the liquid chromatography of these compounds include the use of smaller particles and shorter columns, to improve speed, and the advance of electrochemical detection as an alternative to absorbance and fluorescence detection. Bonded phases, both normal and reversed phase, tend to be preferred over underivatized silica as column supports. Gas chromatography remains of particular value in combination with mass spectrometry, a technique which may form the basis of reference methods. In general, despite the availability of well established analytical methods for fat-soluble vitamins, the wealth of recent literature in this area indicates that there continues to be a need for new assays with enhanced speed, specificity and sensitivity.

Effects of dietary fish oil on serum lipids and blood coagulation in peritoneal dialysis patients

The effects of a daily fish oil supplement rich in eicosapentaenoic acid were studied in 11 stable continuous ambulatory peritoneal dialysis (CAPD) patients. Serum lipids, platelet aggregation studies, and template bleeding times were determined before and after 4 weeks of fish oil treatment. The lipid studies were repeated approximately 20 weeks after stopping fish oil supplement. At the end of the treatment period, serum triglycerides (mean +/- SEM) decreased from 297 +/- 42 to 211 +/- 29 mg/dL (P less than .01), high density lipoprotein (HDL) cholesterol fell from 45 +/- 3 to 41 +/- 3 mg/dL (P less than .05), and low density lipoprotein (LDL) cholesterol increased from 172 +/- 16 to 208 +/- 19 mg/dL (P less than .05). After discontinuing the fish oil supplement, the triglycerides increased to 278 +/- 39 mg/dL, which was no different than the value before fish oil treatment. No significant changes occurred in template bleeding time (TBT), platelet count, hematocrit, or platelet aggregation response. Clinically important uremic bleeding was not apparent. We conclude that in CAPD patients a fish oil supplement favorably effects hypertriglyceridemia and can be ingested without promoting uremic bleeding. The likely beneficial impact on atherogenesis resulting from the lowering of the triglycerides may, however, be counteracted by concomitant changes in HDL- and LDL-cholesterol.

Acute and long-term effects of low-density lipoprotein apheresis on the serum concentrations of vitamins E and A

Serum alpha-tocopherol and retinol concentrations were followed in four heterozygous adults and one homozygous child with familial hypercholesterolemia being treated by regular low-density lipoprotein (LDL) apheresis. Approximately 50% of plasma alpha-tocopherol was eliminated during a single apheresis procedure in the heterozygous adults, while a complete elimination of this vitamin along with LDLs was observed in the homozygous child. Absolute losses of alpha-tocopherol amounted to 13.4-22.5 mg/apheresis and are equivalent to the recommended dietary intake for 1.5 to 2 days. Despite these losses, no changes were observed either in serum alpha-tocopherol levels or in the ratio of alpha-tocopherol/total serum lipids after 12 months regular apheresis treatment. Serum retinol concentrations only showed a small decrease on apheresis, there being apparently no specific elimination of this vitamin. The absolute losses ranged from 42-422 micrograms/apheresis and were, therefore, much lower than the recommended dietary intake of the equivalent of 1500 micrograms retinol/day. It is concluded that no extra supplementation of these vitamins is required during LDL-apheresis therapy, although it may be advisable to monitor vitamin E status in patients on long-term, intensive therapy.

Interactions of vitamin E and penicillamine in the treatment of hereditary avian muscular dystrophy

Our prior work demonstrated that penicillamine treatment of dystrophic chickens delayed the onset of symptoms, partially alleviated contractures, improved muscle function, and lowered serum creatine kinase. Penicillamine, a sulfhydryl compound with reducing properties, also prevented inactivation of glycolytic enzymes by protecting thiol groups. The present study shows that vitamin E enhances the therapeutic effects of penicillamine. Interaction of these two reductants is dose related. With vitamin E as adjunct therapy, the dosage level of penicillamine could be lowered by 50%, thereby minimizing side effects. The therapeutic rationale for two antioxidants is that penicillamine may act primarily in the cytoplasm to prevent oxidative damage, whereas the more hydrophobic vitamin E may protect membrane bilayers. Additionally, penicillamine may prevent collagen cross-linking and, deposition of insoluble collagen in muscle and thus decrease contracture formation. General applications of combined penicillamine and vitamin E therapy are discussed regarding prevention of free radical and oxidative damage in Duchenne dystrophy and a wide range of human diseases.

Serum selenium and vitamin E concentrations in families of lung cancer patients

Whether or not serum selenium and vitamin E (alpha-tocopherol) concentrations were changed was examined among healthy families of lung cancer patients. Family members as a whole (115 sons and daughters of 55 patients with primary lung cancer) were found to have a trend to lower serum selenium levels (0.116 +/- SD 0.024 microgram/ml, 0.05 less than P less than 0.1). Particularly among families of adenocarcinoma patients, the mean level was significantly lower (0.111 +/- 0.019 microgram/ml, P less than 0.05) than that (0.122 +/- 0.014 microgram/ml) in age-ratio matched controls who did not have cancer patients among their second-degree relatives. Serum vitamin E levels (11.85 +/- 2.85 micrograms/ml) were significantly lower among family members of adenocarcinoma patients than the controls (14.1 +/- 3.1 micrograms/ml, P less than 0.01). Serum selenium and vitamin E levels were significantly lower in lung cancer patients (n = 37, mean age, 63.9 +/- 11.2 yr) than in the controls (P less than 0.001). These data suggest that there are familial factors in serum selenium and vitamin E levels among families of lung cancer patients.

Diurnal variation in plasma levels of retinol, tocopherol, and beta-carotene

Diurnal changes in human plasma levels of the fat-soluble vitamins retinol (R), alpha-tocopherol (E), and beta-carotene (CAR) have not been determined. Plasma levels of these three vitamins in 15 healthy volunteers were measured five times over a 24-hour period. Highly sensitive and specific HPLC assays were used. Mean +/- SEM levels for R, E, and CAR were 591 +/- 36 ng/mL, 10.3 +/- 0.6 micrograms/mL, and 271 +/- 28 ng/mL, respectively. Differences between subjects' mean levels were large and highly significant (p less than 0.0001). Relative to the first 8 AM fasting plasma sample, nonfasting plasma levels drawn over the next 24 hours showed no statistically significant or clinically important changes. The percent increases in standard deviation among subjects due to diurnal variation were 1.5%, 3.3%, and 2.3%, respectively, for R, E, and CAR. This implies that sample sizes for cross-sectional studies investigating differences between two treatments in these vitamin plasma levels would need to be increased by 3%, 7%, and 5%, respectively, if measurements are to be taken throughout the day. Plasma levels may be obtained at random during the day, and need not be 8 AM fasting levels. The small addition in variation introduced by diurnal fluctuations would have minimal impact upon the precision of estimates of treatment effect and sample sizes.

Vitamin E is immunostimulatory in calves

Thirty-two Holstein heifer calves, eight per group, were fed 0, 125, 250 or 500 IU/d of supplemental vitamin E/calf, from birth to 24 wk of age, in order to determine the effect on their immune responses. Overall mean lymphocyte blastogenic responses to various T-cell and B-cell mitogens were higher in supplemented calves than in control calves. Mean concentrations of cortisol in serum were lower in all supplemented calves than in control calves. Antibovine herpes-virus type 1 antibody titer (IgG) at 8 and 9 wk, in response to a commercial modified-live intranasal vaccine at 7 wk, was similar in all treatment groups. At 24 wk, in response to a booster at 21 wk, titer was higher in calves given 125 IU of vitamin E/d than in control calves. Based on the concentrations used, it is concluded that supplementation of conventional rations with 125 IU of vitamin E/d may maximize immune responses in calves and may be cost effective.

Development of a method to monitor low molecular mass hydrocarbons in exhaled breath of man: preliminary evaluation of its interest for detecting a lipoperoxidation process in vivo

Low molecular mass hydrocarbons, particularly ethane and pentane, have been measured in expired air of man. The air is collected into 5-10 l polyamide bags. After removal of water vapour and CO2, the hydrocarbons are concentrated on a silicagel column kept at 0 degree C. The column desorption is carried out at 290 degrees C, and the gases are analysed by gas chromatography. A slight but statistically significant increased pentane production was detected in cirrhotic patients.

Platelet hyperaggregability in cystic fibrosis

Platelet function was investigated in 15 patients with cystic fibrosis (CF) and in ten age-matched controls. Marked hyperaggregability of platelets to adrenaline, collagen and arachidonic acid was observed in platelet rich plasma (PRP) prepared from patients with cystic fibrosis. Thromboxane A2 (TXA2) release from these platelets was also markedly enhanced. Hyperaggregability and increased TXA2 release observed in patients with CF was not due to the higher platelet counts in these patients since hyperaggregability was observed even in those patients whose platelet counts were similar to those in controls. Platelet hyperaggregability and increased thromboxane release in these patients were also independent of their body weight and occurred despite supplementation with vitamin E. Hyperaggregability of platelets in CF may be clinically relevant since it may contribute to the pathogenesis of bronchoconstriction through the release of TXA2 and other bronchoconstrictor platelet products such as serotonin.

Serum alpha-tocopherol levels after high-dose enteral vitamin E administration in patients with acute respiratory failure

Serum levels of tocopherols were measured in 5 healthy volunteers and in 14 patients with acute respiratory failure before and after onset of high-dose enteral vitamin E administration. The initial alpha-tocopherol levels did not differ between both groups (12.1 +/- 2.7 micrograms/ml in the volunteers and 11.3 +/- 3.5 micrograms/ml in the patients; mean +/- SD). After oral administration of 1 g d,l-alpha-tocopherylacetate per day the serum levels more than doubled within 1 day and reached a plateau between 22 and 30 micrograms/ml after 3 days in the volunteers. In contrast, application of even 3 g vitamin E/day by gastric tube in the patients with respiratory failure caused only a delayed increase of the serum levels with values nearly doubling after 5-10 days (6 patients), or there was no increase at all (8 patients). Serum alpha-tocopherol did not rise in patients without accompanying highmolecular weight formula diet and in patients with prolonged hemodynamic insufficiency and metabolic acidosis. The age of the patients, the fact of severe blood losses, hemodialysis and hemofiltration and the final outcome of death or survival appeared to be without influence on the response to enteral vitamin application. Neither in the volunteers nor in the patients with acute respiratory failure were there any detectable amounts of beta-, gamma- or delta-tocopherol or of alpha-tocopherolquinone or alpha-tocotrienol.

Views on the wisdom of using antioxidant vitamin supplements

In the Forum that follows, four authorities in nutrition and vitaminology present their divergent views on the use of antioxidant vitamin supplements. In this introduction, the basic dilemma between setting RDAs that insure an absence of deficiency symptoms and those that insure optimal health is discussed, as well as other factors that must be considered to reach a consensus on this controversial topic.

Serum vitamins A and E and carotene in patients with gynecologic cancer

Serum concentrations of vitamin A (retinol), vitamin E (alpha-tocopherol) and total carotene were measured in 88 women with gynecologic cancer (9 vulvar, 15 cervical, 36 endometrial and 28 ovarian carcinomas) and 31 healthy controls. No significant differences were found in the serum levels of the vitamins and carotene in patients with vulvar, cervical or endometrial cancer compared to the controls. The patients with ovarian cancer had a significantly (P less than 0.01) lower mean serum level of vitamin A than the controls, while carotene and vitamin E level were similar in both groups. The results indicate that vitamin A may have a role in the metabolism of patients with advanced ovarian cancer.

Necrotizing myopathy with paracrystalline inclusion bodies in hypervitaminosis E

A necrotizing, nonprogressive myopathy with unusual paracrystalline inclusion bodies is described in a patient who underwent long-term treatment with megadoses of vitamin E. The clinical course and morphological findings suggest a close relationship to the administration of the vitamin. The theoretical pathogenesis of muscle damage and the possible origin of paracrystalline inclusion bodies are discussed.

Are the recommended allowances for dietary antioxidants adequate?

Recommended dietary allowances are standards for maintaining health. Claims that intakes substantially above the allowances may provide protection from xenobiotics and prevent diseases, including cancer, are examined critically for five nutrients that have antioxidant potential. Major criticism is directed at the failure of epidemiologists to recognize that for many of these nutrients, metabolic differences among individuals preclude a direct relationship between dietary intake and plasma or tissue concentration. Also, the fact that no differences in disease incidence have been described within various species of animals that have markedly different metabolic patterns for some of these nutrients has not been considered. It is concluded that the experimental and epidemiological evidence to data that increased intakes of certain nutrients will have beneficial effects on human health are tenuous.

Vitamin E requirements of dairy calves

Thirty-two Holstein heifer calves receiving conventional rations were supplemented with 0 (control), 125, 250, or 500 IU of vitamin E/calf per d. The objective was to determine the optimum requirement based on their overall performance from birth to 24 wk of age. Overall weight gains at 24 wk were higher with 125 and 250 IU and intermediate with 500 IU supplementation compared with no supplementation. Total dry feed consumption and fecal scores were similar among treatments. Serum alpha-tocopherol increased with increased supplementation in a quadratic fashion, being almost doubled with 125 IU compared with that of control calves. Serum creatine kinase, glutamic oxalacetic transaminase, and lactic dehydrogenase values in the unsupplemented calves indicated cell membrane damage. Serum glucose was higher at 8 wk in supplemented calves, but no differences among other serum metabolites were observed. Hematological responses at 4 and 8 wk of age indicated lower mean corpuscular hemoglobin in calves given 500 IU than others and lower mean corpuscular hemoglobin concentration in calves given 500 IU than in calves given 125 or 250 IU. We conclude that supplementation of conventional rations with 125 to 250 IU vitamin E/animal per d can increase the performance of calves.

Protective effects of the glutathione redox cycle and vitamin E on cultured fibroblasts infected by Mycoplasma pneumoniae

The role of the glutathione (GSH) redox cycle and vitamin E as antioxidant defense systems was studied in normal human cultured skin fibroblasts infected by virulent Mycoplasma pneumoniae. In cells infected for 20 h, catalase activity was inhibited by 75% and the intracellular GSH decreased to 32% of its normal values. GSH peroxidase and oxidized glutathione (reductase activities in the infected cells were unaffected.) GSSG glutathione in the medium of the infected cells rose in accordance with the intracellular GSH decrease. The observed elevation in GSSG/GSH ratio was attributed to the increase in intracellular H2O2 content in M. pneumoniae-infected cells due to the marked inhibition in their catalase activity. The protective effect of the GSH redox cycle in infected cells was studied by depletion of cellular GSH, prior to their infection with M. pneumoniae, using buthionine sulfoximine (BSO), a selective inhibitor of gamma-glutamyl cysteine synthetase. After 16 h of incubation with BSO, the GSH levels were reduced to 38% of their normal value and recovered to 55% during 24 h after removal of the inhibitor. BSO had no effect on GSH peroxidase and catalase activities in either infected or noninfected cells. The level of malonyldialdehyde (an indicator of membrane lipid peroxidation) in BSO-treated cells infected by M. pneumoniae was 1.8 times higher than in infected controls. Cells enriched with 0.25 and 2.25 micrograms of vitamin E per mg of protein prior to their infection by M. pneumoniae revealed the following: a lesser degree of catalase inhibition, 46 and 30%, respectively, versus 64% in infected control cells that were not supplemented with vitamin E; lower levels of malonyldialdehyde, 55 and 20% increments, respectively, versus a 140% increment in infected controls; higher residual activity of lactate dehydrogenase, 76 and 96%, respectively, versus 58% in infected controls. Our data indicate that the oxidative damage induced in M. pneumoniae-infected cells due to the increase in intracellular levels of H2O2 and O2- is limited by the host cell GSH redox cycle and by supplementation with vitamin E.

Deficiency of vitamin E in the alveolar fluid of cigarette smokers. Influence on alveolar macrophage cytotoxicity

Cigarette smoking produces oxidant-mediated changes in the lung important to the pathogenesis of emphysema. Since vitamin E can neutralize reactive oxygen species and prevent peroxidation of unsaturated lipids, it may constitute an important component of the lung's defense against oxidant injury. To better characterize the antioxidant protective role of vitamin E, young asymptomatic smokers and nonsmokers were evaluated by bronchoalveolar lavage before and immediately after a 3-wk course of oral vitamin E (2,400 IU/d). Smoker alveolar fluid at baseline was relatively deficient in vitamin E compared with nonsmoker fluid (3.1 +/- 0.7 ng/ml vs. 20.7 +/- 2.4 ng/ml, P less than 0.005). Although smoker alveolar fluid vitamin E levels increased to 9.3 +/- 2.3 ng/ml after supplementation, the levels remained significantly lower than nonsmoker baseline levels (P less than 0.01). This deficiency was explained, in part, by the increased oxidative metabolism of vitamin E to the quinone form in the lungs of smokers compared with nonsmokers. Although the significance of a lower concentration of alveolar fluid vitamin E is unclear, it may compromise the antioxidant protection afforded by the alveolar fluid as it coats the lung's epithelial surface. The protective role of vitamin E was assessed by cytotoxicity experiments, which demonstrated that the killing of normal rat lung parenchymal cells by smoker alveolar macrophages was inversely related to the vitamin E content of the parenchymal cells. These findings suggest that vitamin E may be an important lower respiratory tract antioxidant, and that the deficiency seen in young smokers may predispose them to an enhanced oxidant attack on their lung parenchymal cells.

Selenium, vitamin E, fiber, and the incidence of human cancer: an epidemiologic perspective

It has been hypothesized that selenium, vitamin E, and fiber reduce the risk of specific human cancers. Evidence for a role of selenium is based primarily on animal studies, inverse geographic correlations between intake and site-specific cancer incidence, and an inverse association between serum selenium and subsequent risk of cancer. Certain geographic areas with high fiber intakes have lower rates of colon cancer and, in several case-control studies, consumption of fruits and vegetables has been associated with a lower risk of large bowel cancer. Suspicion that vitamin E might reduce the risk of human cancer is largely theoretical; a protective association has been observed in only 1 small study of breast cancer. The evidence that these 3 dietary factors reduce the risk of human cancer remains incomplete. Future epidemiologic investigations should simultaneously assess a wide variety of dietary factors to address potential confounding and interacting effects. Prospective study designs should be used whenever possible to avoid any influence of cancer on dietary intake or its measurement.

Plasma levels of vitamin E and lipoperoxide during paediatric anaesthesia

We measured plasma levels of vitamin E (total tocopherol) and lipoperoxide in seventeen neonates (less than 10 days), twenty infants (1-12 months) and ten children (1-5 years) during anaesthesia. The seventeen neonates were randomly divided into two groups; seven who received 30 mg X kg-1 of alpha-tocopheryl acetate intramuscularly before anaesthesia and ten who did not. The 20 infants were divided into three groups: Group 1: eight infants who did not receive vitamin E; Group 2: six who received 30 mg X kg-1 of alpha-tocopheryl acetate orally for three days before anaesthesia; Group 3: six who received 30 mg X kg-1 of alpha-tocopheryl acetate intramuscularly three hours before anaesthesia. In the neonates who did not receive alpha-tocopheryl acetate, plasma vitamin E and lipoperoxide levels were unchanged following surgery. In Group 1 infants, plasma vitamin E levels decreased (p less than 0.05) and plasma lipoperoxide levels increased (p less than 0.05). In both neonates who received vitamin E and Group 3 infants the mean plasma vitamin E levels increased significantly (p less than 0.05) following surgery. In Group 2 infants, the levels of plasma vitamin E before surgery were high, as compared to the other groups: however, plasma vitamin E levels decreased following surgery. In the children, the plasma vitamin E levels were unchanged, while the plasma lipoperoxide levels decreased significantly (p less than 0.05) during anaesthesia. It is suggested from our studies that plasma vitamin E levels decrease and plasma lipoperoxide levels increase during anaesthesia and surgery in infants; however, those levels are unchanged in neonates.

Effects of specific nutrients on the immune response. Selected clinical applications

The importance of diet in multiple aspects of the immune response is inescapable. Although only a few trials have attempted to apply knowledge derived from in-vitro and animal data to humans, the ability to modulate or "reset" the immune response by manipulating dietary intake will surely continue to be studied in the future. The role of various nutrients in immunity is reviewed and clinical applications are noted.

Effects of antioxidants on oxidant-induced sister chromatid exchange formation

Stimulated human phagocytes produce sister chromatid exchanges in cultured mammalian cells by a mechanism involving oxygen metabolites. Experiments were designed to determine whether antioxidants inhibit this process. Superoxide dismutase, catalase, and hydroxyl radical scavengers (benzoate, mannitol) protected target Chinese hamster ovary cells from phagocyte-induced sister chromatid exchanges, implicating the involvement of hydroxyl radicals in this chromosomal damage. N-acetylcysteine and beta-carotene were also protective. alpha-Tocopherol (greater than 5 microM) protected target cells exposed to phagocytes but not to enzymatically generated oxidants when the vitamin was added just before the source of oxygen radicals, suggesting, as reported by others, that the principal action of tocopherol in this setting was to inhibit the release of oxidants from phagocytes. On the other hand, cultivation of target cells with supplemental tocopherol protected them from the toxic effects of the enzymatic oxidant-producing system, indicating a role for membrane-associated free radicals in the mechanism of sister chromatid exchange induction. Low concentrations of sodium selenite (0.1-1.0 microM) protected the target cells. However, higher concentrations (10 microM) of selenite had no effect on oxidant-induced sister chromatid exchange formation, and 0.1 mM selenite increased the number of exchanges. Sodium selenite concentrations of 0.1 mM also decreased the intracellular glutathione concentration of target cells during an oxidant stress, and reducing target cell glutathione concentrations with buthionine sulfoximine increased their sensitivity to oxygen-related chromosomal damage. Therefore, the potentiation of oxygen radical-induced chromosomal damage observed with high concentrations of selenite may result from a decrease in the thiol antioxidant defense systems within the cell. The findings suggest that the hydroxyl radical has an important role in the production of phagocyte-induced cytogenetic injury, membrane-derived intermediates may be involved, depletion of intracellular glutathione renders cells more susceptible to this injury, and supplementation of target cells with antioxidants can protect them from oxygen radical-generated chromosomal injury.

Symptomatic vitamin E deficiency in cystic fibrosis

A girl with cystic fibrosis who developed a neurological syndrome probably secondary to vitamin E deficiency at the age of 10 years is described. The severity of the deficiency and the early development of neurological features probably result from reduced intraluminal bile salt concentrations in addition to the pancreatic insufficiency.

Micronutrient requirements of cancer patients

Several major factors may influence the micronutrient requirements of the patient with cancer. These factors include the metabolic state of the malignancy and its effects on host metabolism, the catabolic effects of antineoplastic therapy, and other physiologic stresses commonly associated with the treatment of cancer, i.e., surgery, fever and infection. Although the nutritional importance of vitamins, minerals and trace elements is recognized, the optimal daily dose that will preserve lean body mass without enhancing tumor growth, is not known. Recommended Dietary Allowances (RDAs), where established, are based on populations with nonmalignant diseases. However, supplementation with vitamins, minerals, and certain trace elements is recommended for the cancer patient who requires prolonged parenteral support, since clinically relevant deficiency states have been described. The effect of malignancy on the metabolism of several of these micronutrients (iron, ascorbic acid, alpha tocopherol, selenium, zinc, copper) is discussed.

Suppression of severe retinopathy of prematurity with vitamin E supplementation. Ultrastructural mechanism of clinical efficacy

Three clinical trials enrolling 418 infants (less than or equal to 1500 g birth weight) and an ultrastructural data base of 71 pairs of whole eye donations have elucidated the efficacy of vitamin E in suppressing the development of severe retrolental fibroplasia (ROP). Only continuous vitamin E supplementation to adult physiologic levels from the first hours of life suppresses the development of severe ROP. Supplementation does not increase the incidence of necrotizing enterocolitis, sepsis, intraventricular hemorrhage, or mortality. Only multivariate analysis, which considers all risk factors simultaneously, is appropriate when appraising the efficacy of supplementation since all the clinical risk factors uniquely impinge on the oxygen dynamics of the developing retina. Mesenchymal spindle cells are the cellular mediators of the induction of ROP by oxygen in which increased oxygen tension triggers extensive gap junction formation between adjacent spindle cells. This cellular event, which occurs as early as four days of life, halts the normal vasoformative process and triggers neovascularization, which becomes clinically evident some 8 to 12 weeks later.

The Quebec Cooperative Study of Friedreich's Ataxia: 1974-1984--10 years of research

In this paper the author reviews the progress accomplished in the understanding of Friedreich's disease since the start of the "Quebec Cooperative Study of Friedreich's Ataxia" in 1974. The last ten years have indeed seen important strides taken in the definition and nosography of the hereditary ataxias and the characterization of a number of new entities. Biochemically, the principal leads uncovered during the initial prospective survey, have been pursued to great detail. Unfortunately no clear-cut constant and severe enzyme block in the principal metabolic pathways has yet been identified, despite intensive studies. It is postulated that the defect may instead be a regulatory one and involve a decreased availability or utilization of one of the vitamin cofactors that are known experimentally, or clinically, to produce central nervous system damage with ataxia: Vitamin E, Biotin or Pantothenic Acid. Studies in that direction and in molecular genetics to localize the Friedreich's disease gene are being undertaken for the next phase of the Cooperative Study.

Adverse effects of drugs on the blood

Amongst adverse drug reactions blood dyscrasias are not frequent, but they may have serious consequences. Compared with Sweden, data from The Netherlands are scarce. It is to be expected that regular reports about the incidence of drug-induced blood dyscrasias may play an important role in general prevention. Blood dyscrasias may be caused by a variety of drugs, from many pharmacotherapeutic groups with diverse chemical structures and with all application forms. Metabolism and distribution may influence the activity of drugs. Drug-induced anaemias, including aplastic anaemia, are briefly discussed. Toxic and immune mechanisms may occur. The same holds with regard to the leucopenias. Drug-induced thrombocytopenia is mainly immune-mediated (cytostatics being excluded as causative agents). In immune-mediated drug-induced blood dyscrasias often haptens must be formed. They can be formed in vivo in the liver or in the lymphocytes. In some cases they appear to be formed even in vitro. Tracing the causative agent of a dyscrasia, be it a drug or some other substance, requires a series of investigations, comprising usage of the drug, serology and cell culture. Provocation tests are seldom justified. Distinct preventive measures can be taken to minimize the risk of blood dyscrasias: avoidance of risky drugs, awareness of the patient about early clinical signs and haematological control.

Relation of serum vitamins A and E and carotenoids to the risk of cancer

Epidemiologic studies suggest that low carotene intake and low levels of serum retinol may be associated with an increased risk of cancer. Likewise, in some animal studies vitamin E has been associated with a reduced rate of induced cancers. Therefore, we measured retinol, retinol-binding protein, vitamin E (alpha-tocopherol), and total carotenoids in serum collected in 1973 from 111 participants in the Hypertension Detection and Follow-up Program who were free of cancer at the time but were diagnosed as having cancer during the subsequent five years. These measurements were compared with those in 210 controls who were matched for age, sex, race, and time of blood collection, and who remained free of cancer. Mean values for retinol were similar for cases and controls (67.3 and 68.7 micrograms per deciliter, respectively [95 per cent confidence limits for case-control difference, -6.7 to 3.5]). Values were also similar for retinol-binding protein (6.01 and 5.94 mg per deciliter [-0.42 to 0.56]), and carotenoids (114.5 and 111.6 micrograms per deciliter [-9.1 to 15.9]). The mean base-line retinol level in the 18 subjects with subsequent lung cancer was higher than that in their matched controls (79.0 vs. 71.4 micrograms per deciliter, -4.9 to 19.7). Serum vitamin E levels were somewhat lower in subjects who later had cancer than in controls (1.16 and 1.26 mg per deciliter, -0.22 to 0.02), in part because of the confounding effect of serum cholesterol levels (when adjusted for lipid levels, the case-control difference was -0.05 mg per deciliter; -0.17 to 0.07). These data do not support hypotheses relating intake or serum levels of antioxidant vitamins to a reduced cancer risk.