Moderate hyperoxia (40%) increases antioxidant levels in mouse tissue

BACKGROUND: Oxygen is routinely administered to patients to improve clinical outcome. Since studies have shown that administering 100% oxygen can cause unwanted side effects, intermediate concentrations of 40% oxygen are used in clinical practice. In this study, we examined whether the breathing of 40% oxygen causes beneficial effects upon tissue levels of antioxidants such as vitamin E, vitamin C, and glutathione. METHODS: Four-month-old mice were separated into two groups: control (n = 11) and experimental (n = 11). The treatment group was administered 40% oxygen for 10 days. Brain, heart, lung, liver, testes, and skeletal muscle were harvested and tissue antioxidant levels were determined by HPLC. RESULTS: Vitamin E concentrations were higher in brain, heart, lung, liver, and testes of the treatment group (P < 0.05). Glutathione concentrations were higher in the lung tissue only (P < 0.05). No differences were found in vitamin C levels. CONCLUSIONS: The data suggest that mice respond to oxidative stress by increasing tissue vitamin E incorporation and cellular synthesis of glutathione in the lung when exposed to moderate levels (40%) of hyperoxia.     

Antioxidative effects of exogenous nitric oxide versus antioxidant vitamins on renal ischemia reperfusion injury

The objectives of this study were to compare the protective influence of exogenous nitric oxide on renal ischemia reperfusion (I/R) injury with that of the antioxidant vitamins C and E. Sprague-Dawley rats were divided into three groups ( n=12 per group). Normal saline solution was given in group 1, a vitamin C (200 mg/kg/d) plus vitamin E (100 mg/kg/d) combination in group 2 for 3 days before operating and Na-nitroprusside (5 mg/kg/d) in group 3 before reperfusion. The left kidneys were exposed to warm ischemia for 40 min followed by reperfusion for 90 min. The right kidneys were used as internal controls. After both kidneys were removed, histopathological examinations were performed, and oxidative and antioxidative parameters were measured. In the postischemic reperfused rat kidneys, the renal lipid peroxidation level was significantly lower, and the renal GSH level higher in the group given Na-nitroprusside compared with groups 1 and 2. Renal specific xanthine oxidase activity was also significantly lower in the group treated with Na-nitroprusside than in the groups given vitamins or saline. There was a significant, negative correlation between lipid peroxidation and reduced glutathione levels. Our results suggest that the exogenous nitric oxide (Na-nitroprusside) inhibits xanthine oxidase, and has more apparent preventive features for renal I/R injury than the antioxidant vitamins C+E.     

Effects of testosterone and vitamin E on the antioxidant system in rabbit testis

The aim of the study was to investigate the effects of testosterone propionate and vitamin E on the antioxidant system in the testis. Thirty-two male New Zealand White rabbits were randomly divided into four groups. The first group was used as control. The second group was injected with testosterone propionate, the third group vitamin E and the fourth group vitamin E and testosterone propionate combination. All treatments were carried out during 6 weeks and oxidative parameters were evaluated in homogenized testicular tissue. The levels of vitamin E and the activity of glutathione peroxidase were lower (P < 0.05) in the testosterone group than in controls. However, vitamin C and malondialdehyde levels were higher (P < 0.05) in this group than in controls. The levels of reduced glutathione, beta-carotene, vitamin C and E increased, but malondialdehyde levels decreased in the vitamin E group, when compared with controls (P < 0.05). Vitamin E and beta-carotene levels were significantly higher (P < 0.05) in the combination group than in testosterone group. However, MDA levels were lower (P < 0.05) in combination group than in the testosterone group. In conclusion, administration of testosterone propionate led to a significant elevation of oxidative stress. Vitamin E is quite an effective antioxidant which protects rabbit testis against lipid peroxidation, and, testosterone-induced lipid peroxidation could be improved by additional vitamin E treatment.     

The levels of glutathione peroxidase, vitamin A, E, C and lipid peroxidation in patients with transitional cell carcinoma of the bladder

OBJECTIVE: To assess the levels of erythrocyte glutathione peroxidase (GSH-Px), and the serum levels of antioxidant vitamins (A, E and C), selenium and malondialdehyde (MDA) in patients with transitional cell carcinoma (TCC) of the bladder. PATIENTS, SUBJECTS AND METHODS: The study comprised 91 people (23 healthy controls and 68 patients with TCC). Erythrocyte GSH-Px activity was measured by spectrophotometry, high-performance liquid chromatography to detect serum levels of vitamins and MDA, and fluorometry to detect serum levels of selenium. RESULTS: The serum levels of vitamin A, E and C, and selenium were significantly lower (P < 0.05) in patients with TCC than in controls. However, erythrocyte GSH-Px activities (P < 0.05) and serum MDA levels (P < 0.01) were significantly higher in patients with TCC than in the controls. CONCLUSIONS: Levels of free oxygen species were higher, and antioxidant vitamin and selenium levels lower, in patients with bladder TCC than in controls. These findings, with the results of previous animal studies, suggest that giving vitamin A, C, E and selenium may be beneficial in preventing and treating human bladder cancer.     

Antioxidant status of children with steroid-sensitive nephrotic syndrome

Eighteen children with steroid-sensitive nephrotic syndrome (SSNS) were studied. The control group comprised 20 healthy children. The following indirect parameters of reactive oxygen species activity were determined in nephrotic patients during four stages of the disease (full relapse before prednisone administration, disappearance of proteinuria, prednisone cessation, unmaintained remission): plasma malondialdehyde (MDA) levels, copper/zinc superoxide dismutase (CuZn SOD) activity and glutathione peroxidase (GPX) activity in erythrocytes, reduced glutathione (GSH) and vitamin C levels in whole blood, and vitamin E level in serum. Increased MDA levels, reduced vitamin C levels, and enhanced CuZn SOD activity were found in relapse. GSH concentration was high during all four stages. Vitamin E level was also increased, parallel to the pattern of serum lipids. GPX activity remained low during the proteinuria stage and in remission. We conclude that the majority of abnormal findings can be attributed to the hyperlipidemia of NS. Low GPX activity may be a factor limiting the antioxidant capacity in NS. The present study is inconclusive regarding the role of free radicals in the proteinuria of NS. Received October 13, 1997; received in revised form April 13, 1998; accepted April 14, 1998     

Antioxidant supplementations in vitro improve rat sperm parameters and enhance antioxidant enzyme activities against dimethoate-induced sperm damages

Organophosphorus compounds are currently among the most frequently used pesticides worldwide, and therefore, the potential for human exposure to man is considerable. Their toxicity results in negative effects on many organs and systems such as the male reproductive system. So, vitamins that can offer spermatozoa protection are of great importance. This study was designed to investigate (i) the possibility of dimethoate, an organophosphate insecticide, to induce oxidative stress response in rat spermatozoa in vitro and its effect on antioxidant defence system and (ii) the role of vitamin C and vitamin E in alleviating the cytotoxic effects of dimethoate Epididymal spermatozoa were incubated for 3 h at 37 °C with different concentrations of dimethoate (50, 100 and 200 μm) without vitamins or pre-incubated with 20 mm of vitamin C or 2 mm of vitamin E. Sperm parameters, malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) levels were performed. Dimethoate caused a significant induction of oxidative damage in spermatozoa at different concentrations as evidenced by increased MDA levels. However, a significant decrease in sperm mobility, viability and activities SOD, CAT and GPx was observed. Vitamins pre-treated spermatozoa showed a significant protection against the cytotoxic effects induced by dimethoate on studied parameters.     

Protective effects of vitamins A and E pretreatment in venous ischemia/reperfusion injury

It has been suggested that venous ischemia is more injurious to tissue viability than is arterial ischemia of equivalent duration. The precise mechanism of tissue damage due to venous ischemia is still not well-determined. Current research has shown that it is multifactorial, and that lipid peroxides, prostanoid metabolism, and a free radical mechanism are the major contributors. Vitamins A and E are lipid-soluble vitamins that have been suggested to be successful in the treatment of arterial ischemia/reperfusion injury due to their antioxidant properties. In the present study, the authors examined the protective effects of vitamins A and E pretreatment on reperfusion injury induced by venous occlusion of rat epigastric island flaps based on an epigastric artery and vein pedicle. In the first part of the study, to determine critical ischemia time, epigastric island skin flaps (3 x 6 cm) were elevated on their vascular pedicles in 40 male Sprague Dawley rats. Total venous occlusion of the skin flap was produced by ligating all draining veins and clamping the epigastric vein. Arterial inflow was left intact. Rats were randomly assigned to five groups (n=8) for 2, 5, 7, 9, and 10 hr of venous ischemia. Despite the occurrence of widespread reperfusion injury, reflow was established (p<0.005) at 9 hr. In the second part of the study, 20 rats were randomly divided into four groups (n=5). The effects of vitamins A and E following 9 hr ischemia/reperfusion injury were examined. Rats were pretreated with vitamin E, vitamin A and vitamins A+E for 5 days. At the end of the fifth day, each rat had undergone an epigastric island skin flap and venous occlusion, as described above. Mean surviving flap area (percent) and plasma lipid peroxides (TBARs), total thiol content (t-SH), glutathione peroxidase (Gpx), and superoxide dismutase (SOD) were determined for each rat. Results suggest that, in the prevention of venous ischemia/reperfusion injury, vitamin A and vitamin E are not effective when used as single agents; however, when used in combination, they significantly increase surviving flap area by a synergistic effect.     

Oxidative stress in patients treated with continuous ambulatory peritoneal dialysis (CAPD) and the significant role of vitamin C and E supplementation

Purpose

Chronic renal failure patients undergoing peritoneal dialysis (PD) are characterized by increased oxidative stress (OS), which is associated with enhanced cardiovascular risk. Moreover, oxidative stress also contributes to peritoneal membrane changes and ultrafiltration failure. The aim of this study was to evaluate OS in PD patients and the effect of treatment with ascorbic acid and α-tocopherol.

Methods

Plasma, erythrocyte, urine, and peritoneal effluent samples from 20 patients on PD were evaluated for glutathione peroxidase and superoxide dismutase activity, total antioxidant capacity (TAC) and malondialdehyde (MDA) levels, as well as protein carbonyl formation, before and after administration of vitamin C, alone or in combination with vitamin E, in comparison with 10 apparently healthy control individuals.

Results

All studied markers showed enhanced OS in the PD group, compared to controls. The supplementation of vitamin C and E resulted in improvements of all the OS markers, as indicated by increased erythrocyte antioxidant enzymes activity and TAC levels, as well as decreased MDA concentration and carbonyl compound formation.

Conclusions

The oral supplementation of antioxidant vitamins C and E, in combination, can lead to decreased OS, thus providing a useful and cost-effective therapeutic option in PD patients.     

Effects of prenatal vitamins A, E, and C on the hypoplastic hearts of fetal rats with diaphragmatic hernia

Background/Aim

Nitrofen induces heart hypoplasia together with congenital diaphragmatic hernia (CDH) in rats. Intracellular oxidative stress might be one of the mechanisms of action of the teratogen, and vitamin A has been shown to reverse in part these effects when administered simultaneously or shortly after it. This study aims at testing the hypothesis that vitamin A and other antioxidant vitamins, such as E and C, could improve myocardial development even when administered late in gestation, a likely useful period for prenatal medication.

Material and Methods

Time-mated Sprague-Dawley female rats were exposed to either vehicle (control) or 100 mg of nitrofen (experimental) on day 9.5 of gestation. In 3 additional groups, the animals were exposed to vitamin A (total 15 000 IU), vitamin E (total 150 IU), or vitamin C (total 150 IU) on days 16, 17, and 18. The fetuses were recovered on day 21, and randomly selected hearts of those with CDH were processed for histologic studies (hematoxylin-eosin and periodic acid-Schiff stainings), DNA and protein contents, and ki-67 (proliferation) and terminal deoxynucleotidyl transferase-mediated dUTP-biotin end labeling (apoptosis) studies. The differences among groups were assessed by analysis of variance with Bonferroni/Dunn post hoc tests and a threshold of significance of P < .05.

Results

Nitrofen induced heart hypoplasia in terms of decreased heart/body weight, cell mass (less DNA and protein), and proportion of proliferating cells with increased apoptosis. Vitamin C alleviated weight hypoplasia and the 3 vitamins were able to restore cell mass and to reestablish near-normal figures of proliferation and apoptosis.

Conclusions

Antioxidant vitamins A, E, and C given late in gestation alleviate heart hypoplasia that accompanies CDH in the rat model. This timing suggests that the beneficial effects are exerted on the maturational phase of development.     

Deficiencies of Vitamins in CAPD Patients: The Effect of Supplementation

Concentrations of the vitamins B₁, B₂, B₆, B₁₂, C, folic acid,A, E and ß-carotene were determined in blood and 24-hdialysate in 44 CAPD patients. Twenty-five of these patientswere studied during chronic treatment (mean 313 days, range60–1034 days). Nineteen patients were studied during training.In a longitudinal study, 11 patients were analysed again after77–507 (mean 238) days. In both patient groups a considerable portion of patients (11%–64%)had blood concentrations indicative of a deficiency of the vitaminsB₁, B₆, C and folic acid. The average concentrations of thesevitamins were normal in both groups. The only abnormal findingwas the mean EGOT activity being deficient in patients on chronictreatment. Mean concentrations of vitamin A were above normalin both groups. In the longitudinal study a significant increaseof vitamin B₂ and a decrease of vitamin B₆ in blood was found. When compared to 24-h excretion in normal urine, loss with 24-hdialysate was low for vitamin B₁, normal to relatively highfor vitamin B₂ and B₆, but extremely high for vitamin C andfolic acid. The vitamins B₁₂, A, E and carotenoids were hardlydetectable in the dialysate. In ten other patients the effect of daily supplementation with2 mg vitamin B₆, 100mg vitamin C and 400 µg folic acidwas analysed during a 16-week period. In all patients a significantincrease in blood concentrations was obtained. It is concludedthat these dosages were sufficient to maintain a normal statusof these vitamins in CAPD patients.     

Dietary antioxidants and magnesium in type 1 brittle asthma: a case control study

BACKGROUND: Type 1 brittle asthma is a rare form of asthma. Atopy, psychosocial factors and diet may contribute to this condition. As increased dietary magnesium has a beneficial effect on lung function and selenium, vitamins A, C and E have antioxidant properties, a study was undertaken to test the hypothesis that patients with brittle asthma have diets deficient in these nutrients compared with subjects with non-brittle asthma and healthy adults. METHODS: A case control study of the dietary intakes of 20 subjects with brittle asthma, 20 with non-brittle asthma, and 20 healthy adults was performed using five day weighed dietary records. Intake of magnesium was the primary outcome measure with selenium and vitamins A, C and E as secondary outcomes. Serum levels were measured at the same time as the dietary assessment. RESULTS: Sixty subjects (27 men) of mean age 49.5 years were recruited and completed the study. Subjects with brittle asthma had statistically lower median dietary intakes of vitamins A and E than the other groups (vitamin A: brittle asthma 522.5 micrograms/day, non-brittle asthma 869.5 micrograms/day, healthy adults 806.5 micrograms/day; vitamin E: brittle asthma 4.3 mg/day, non-brittle asthma 4.6 mg/day, healthy adults 4.5 mg/day). Median dietary intakes for the other nutrients were not significantly different between groups. Serum levels were within normal ranges for each nutrient in all subjects. Intakes less than the reference nutrient intake (RNI) for magnesium and vitamins A and C, and less than the safe intake (SI) for vitamin E were more likely in patients with brittle asthma than in those with non-brittle asthma. CONCLUSION: Nutrient deficiency and reduced antioxidant activity may contribute to disease activity in type 1 brittle asthma, although a prospective study of replacement therapy will be needed to confirm this hypothesis.     

Endurance Training and Glutathione-Dependent Antioxidant Defense Mechanism in Heart of the Diabetic Rats

Regular physical exercise beneficially influences cardiac antioxidant defenses in normal rats. The aim of this study was to test whether endurance training can strengthen glutathione-dependent antioxidant defense mechanism and decrease lipid peroxidation in heart of the streptozotocin-induced diabetic rats. Redox status of glutathione in blood of diabetic rats in response to training and acute exercise was also examined. Eight weeks of treadmill training increased the endurance in streptozotocin-induced diabetic rats. It did not affect glutathione level in heart tissue at rest and also after exercise. On the other hand, endurance training decreased glutathione peroxidase activity in heart, while glutathione reductase and glutathione S-transferase activities were not affected either by acute exhaustive exercise or endurance training. Reduced and oxidized glutathione levels in blood were not affected by either training or acute exercise. Conjugated dienes levels in heart tissue were increased by acute exhaustive exercise and also 8 weeks treadmill training. Longer duration of exhaustion in trained group may have contributed to the increased conjugated dienes levels in heart after acute exercise. Our results suggest that endurance type exercise may make heart more susceptible to oxidative stress. Therefore it may be wise to combine aerobic exercise with insulin treatment to prevent its adverse effects on antioxidant defense in heart in patients with diabetes mellitus.Key words: Streptozotocin, experimental diabetes mellitus, oxidative stress, conjugated dienes, heart, blood, rat     

Effect of oral vitamin E and C therapy on calcineurin inhibitor levels in heart transplant recipients.

BACKGROUND: A recent prospective trial demonstrated that oral vitamins C and E retard the early progression of transplant-associated coronary arteriosclerosis; as a result, a number of centers have added these agents to their maintenance regimens. This study reviewed the impact of vitamin E and C supplementation on calcineurin inhibitor trough concentrations. METHODS: A retrospective chart review of the first 29 heart transplant patients prescribed anti-oxidant agents was performed. Twenty-two patients taking cyclosporin A (CsA) and 7 patients taking tacrolimus were prescribed vitamin C (500 mg twice a day) and vitamin E (400 IU twice a day). Serum chemistries and drug levels were measured before and after vitamin therapy was initiated. RESULTS: The baseline CsA trough concentration (mean +/- SD) was 137 +/- 39 ng/ml and it declined to 99 +/- 54 ng/ml (p = 0.007) after anti-oxidant therapy was initiated. The average percentage decrease in the CsA trough concentration was 30%. No significant changes were seen in the patients taking tacrolimus. CONCLUSIONS: These data demonstrate that supplementation with the anti-oxidant agents vitamin C and vitamin E decreases CsA concentrations but does not appear to effect tacrolimus concentrations. Although more detailed pharmacokinetic analysis is necessary to clarify the exact mechanism of this interaction, physicians who take care of transplant recipients should be aware that more frequent CsA concentration monitoring is warranted after initiating these anti-oxidant agents.     

An in vitro study of osteoblast vitality influenced by the vitamins C and E

Vitamin C and vitamin E are known as important cellular antioxidants and are involved in several other non-antioxidant processes. Generally vitamin C and vitamin E are not synthesized by humans and therefore have to be applied by nutrition. The absence or deficiency of the vitamins can lead to several dysfunctions and even diseases (e.g. scurvy). The main interest in this study is that vitamin C and E are known to influence bone formation, e.g. vitamin C plays the key role in the synthesis of collagen, the major component of the extracellular bone matrix. In the present study we evaluate the effect of ascorbic acid (vitamin C) and ??-tocopherol (vitamin E) on the proliferation and differentiation of primary bovine osteoblasts in vitro. Starting from standard growth medium we minimized the foetal calf serum to reduce their stimulatory effect on proliferation. An improved growth and an increased synthesis of the extracellular matrix proteins collagen type I, osteonectin and osteocalcin was observed while increasing the ascorbic acid concentration up to 200 ??g/ml. Furthermore the effects of ??-tocopherol on cell growth and cell differentiation were examined, whereby neither improved growth nor increased synthesis of the extracellular matrix proteins collagen type I, osteonectin and osteocalcin were detected. Further investigations are necessary to target at better supportive effect of vitamins on bone regeneration, and healing.     

Effect of vitamins on the lipid profile of patients on regular hemodialysis

OBJECTIVE: The aim of this study was to investigate the lipid-lowering effect of vitamins compared to placebo and their short-term supplementation safety in patients on hemodialysis. MATERIAL AND METHODS: Eighty-four hemodialysis patients were randomly allocated to four therapeutic groups. Each group (n = 21) received one of the following treatments: vitamin C (200 mg), E (200 mg), D3 (50,000 IU) or placebo daily. Serum triglyceride, total cholesterol, low-density lipoprotein cholesterol (LDL-c), and high-density lipoprotein cholesterol (HDL-c) were measured before and following 3 months of vitamin therapy. RESULTS: LDL-c and total cholesterol levels as well as the ratios of LDL-c to HDL-c and cholesterol to HDL-c significantly decreased after vitamin C therapy. Triglyceride and the ratio of triglyceride to HDL-c significantly decreased following vitamin D3 therapy. HDL-c increased and the ratio of LDL-c to HDL-c decreased significantly after vitamin E therapy. No major side-effects were encountered during the 3 months' trial. CONCLUSIONS: Short-term supplementary vitamins are safe and beneficial for treatment of lipid abnormalities in hemodialysis patients.     

Enzymatic antioxidant defence mechanism in rat intestinal tissue is changed after ischemia-reperfusion. Effects of an allopurinol plus antioxidant combination.

OBJECTIVES: To establish the antioxidant status of rat intestinal tissues after ischemia-reperfusion and to determine if pretreatment with an allopurinol and antioxidant vitamin combination gives any protection against mucosal injury. EXPERIMENTAL ANIMALS: Twenty rats were divided into 4 groups of 5 animals each. METHODS: Group 1 (control) rats were not subjected to ischemia-reperfusion and received no allopurinol plus vitamin combination; group 2 rats received vitamins C (200 mg/kg) and E (100 mg/kg) and allopurinol (50 mg/kg) combination daily for 3 days preoperatively; group 3 rats were subjected to ischemia-reperfusion only; and group 4 rats were subjected to ischemia-reperfusion and received the vitamin and allopurinol combination. MAIN OUTCOME MEASURES: Activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT) enzymes, the level of thiobarbituric acid-reagent substances (TBARS) and histologic grading of tissue samples. RESULTS: SOD and GSH-Px activities were decreased, but the CAT activity and TBARS level increased. Pretreatment of the rats with the allopurinol-vitamin C-vitamin E combination did not have any significant effect on the enzyme activities. However, it resulted in important reductions in the TBARS tissue levels. Histologic investigation revealed significant mucosal injury in group 3 rats compared with group 4 rats (mean [and standard deviation] for grading, 4.6 [0.5] versus 1.8 [0.4]). CONCLUSIONS: The enzymatic antioxidant defence system was significantly changed after ischemia-reperfusion and intestinal tissue was exposed to increased oxidant stress, the results of which were peroxidation of some cellular structures and increased concentrations of oxidative products. Although antioxidant treatment did not drastically affect the enzyme activities or afford complete protection of cellular structures against deformation, it apparently could eliminate oxygen radicals and prevent peroxidative reactions.     

Effect of vitamins C and E on sulfated proteoglycan metabolism and sulfatase and phosphatase activities in organ cultures of human cartilage

Summary Previous studies conducted in cell culture utilizing chondrocytes isolated from human articular cartilage showed that inclusion of ascorbic acid in the nutrient medium resulted in an increase in the net biosynthesis of sulfated proteoglycans concomitant with a reduction in the activities of arylsulfatases A and B. This suggested a possible connection between the stability of the sulfated macromolecules and the activity of these desulfating enzymes. To examine whether this relationship also was operative in a more native milieu, the effect of ascorbate on these parameters was measured in an organ culture system using slices of human articular cartilage where the structural extracellular framework surrounding the chondrocytes is comparable to that present in vivo. In addition, since numerous studies have shown that vitamin E inhibits lysosomal enzymes, the effect of alpha-tocopherol on these parameters was also investigated. Concurrent with an inhibition of arylsulfatase A and B activities, an increase in sulfated proteoglycan biosynthesis per unit of DNA as reflected in³⁵S-sulfate uptake was present in all cartilage specimens examined 6 days after the introduction of vitamin C in the culture fluid. A larger fraction of the newly synthesized sulfated macromolecules was incorporated into the matrix of the tissue in samples maintained in the vitamin-supplemented cultures. Supplementation of the organ culture medium with vitamin E resulted in the inhibition of arylsulfatase A and no change in arylsulfatase B activities. In contrast to the action of vitamin C which stimulated acid phosphatase activity, a potent inhibition of this enzyme was effected by vitamin E. Sulfated proteoglycan content was greatly enhanced by alpha-tocopherol, although the vitamin did not alter the distribution of the newly synthesized molecules between the tissue and medium fractions. Inhibition of acid phosphatase and arylsulfatase A by alpha-tocopherol was evident in tissue lysates and partially purified enzyme preparations. This implies a direct interaction between the enzymes and vitamin E. The actions of alpha-tocopherol and ascorbate on cartilage enzymes and structural components were dissimilar. Both vitamins, however, appeared to enhance the stability of sulfated proteoglycans in the complex structure comprising articular cartilage.     

Treatment of hyperhomocysteinemia in pediatric heart transplant recipients.

BACKGROUND: Graft coronary artery vasculopathy is the main cause of late morbidity and mortality in pediatric cardiac allograft recipients. Growing evidence suggests that elevated plasma homocysteine levels are associated with cardiac allograft vasculopathy following heart transplantation. The purpose of this study was to evaluate the effect of vitamin supplementation as a potential strategy for reducing homocysteine levels in pediatric heart transplant recipients and examine creatinine levels as potential determinants of plasma homocysteine concentration after transplantation. METHODS: We studied 27 pediatric heart transplant patients with homocysteine levels higher than normal. All children received vitamin supplementation (vitamin B(12), vitamin E, vitamin A and folic acid). During treatment, levels of homocysteine, vitamins and creatinine were evaluated after 3, 6, 9 and 12 months. RESULTS: We observed a significant homocysteine concentration decrease after treatment at every determination, whereas no significant change occurred for creatinine. Vitamin B(12) serum level increased markedly, whereas folic acid, vitamin E and vitamin A serum levels showed only minor increases. CONCLUSIONS: We observed a significant increase of mean levels of vitamin B(12) and a moderate increase in the other 3 vitamins. We also observed a significant reduction in homocysteine levels, which returned to normal levels for age. In our patients, there was a correlation, before and after treatment, between homocysteine and creatinine levels, but there was no a direct correlation between creatinine serum levels and homocysteine reduction. We conclude that vitamin supplementation reduces and may normalize homocysteine serum level after pediatric heart transplantation.     

Cancer of the prostate: influence of nutritional factors. Vitamins, antioxidants and trace elements

CANCER OF THE PROSTATE AND VITAMINS: Four vitamins have been studied, vitamins A, E, D and C. the results of these studies have been contradictory. Vitamin A and vitamin E would have a protective effect. ANTIOXIDANTS: Carotenes have an activity similar to that of vitamin A. Beta-carotene was positively associated with risk of cancer of the prostate in one study while two others were unable to demonstrate any relationship. Lycopene, the red color in fruits and vegetables, particularly tomatoes, would contribute to a lower risk of prostate cancer. TRACE ELEMENTS: Cadmium would increase the risk of cancer while selenium would have a protective effect. However studies concerning selenium carry certain methodological biases.     

A randomized, double-blind, placebo-controlled trial of supplementary vitamins E, C and their combination for treatment of haemodialysis cramps.

BACKGROUND: Muscle cramps that improve after carnitine or vitamin E therapies are common in haemodialysis (HD) patients. Because vitamin C participates in carnitine biosynthesis, and its levels are reduced in uraemia, subclinical vitamin C depletion may contribute to HD cramps. Our aim was to determine the effects of vitamins C, E and their combination on the frequency and intensity of HD cramps. METHODS: In this placebo-controlled, double-blind study, 60 HD-patients were randomized into four therapeutic groups. Each group (n=15) received six identical capsules daily for 8 weeks, containing one of the following: vitamin E (400 mg), vitamin C (250 mg), their combination, or placebo. RESULTS: The frequency and intensity of HD cramps decreased significantly in all three vitamin groups compared with the placebo group at the end of the trial, and compared with the pre-treatment values. At the end of the trial, vitamins E, C, their combination, and placebo produced cramp reductions of 54, 61, 97 and 7%, respectively. The percentage cramp reduction had no significant correlation with age, sex, aetiology of end-stage renal disease, serum electrolytes or HD duration, but showed a positive correlation (r=0.33, P=0.01) with the type of therapy. No vitamin-related adverse effects were encountered during the trial. CONCLUSION: Short-term treatment with the combination of vitamins E and C is safe and effective in reducing HD cramps; however, its safety for prolonged therapy has yet to be evaluated in HD patients.