***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: BACKGROUND Results from observational studies suggest that micronutrient status is a determinant of the progression of human immunodeficiency virus ( HIV ) disease . METHODS We enrolled 1078 pregnant women infected with HIV in a double-blind , placebo-controlled trial in Dar es Salaam , Tanzania , to examine the effects of daily supplements of vitamin A ( preformed vitamin A and beta carotene ) , multivitamins ( vitamins B , C , and E ) , or both on progression of HIV disease , using survival  models . The median follow-up with respect to survival was 71 months ( interquartile range , 46 to 80 ) . RESULTS Of 271 women who received multivitamins  , 67 had progression to World Health Organization ( WHO ) stage 4 disease or died -- the primary outcome --as compared with 83 of 267 women who received placebo ( 24.7 percent vs. 31.1 percent ; relative risk , 0.71 ; 95 percent confidence interval , 0.51 to 0.98 ; P=0.04 ) . This regimen was also associated with reductions in the relative risk of death related to the acquired immunodeficiency syndrome ( 0.73 ; 95 percent confidence interval , 0.51 to 1.04 ; P=0.09 ) , progression to WHO stage 4 ( 0.50 ; 95 percent confidence interval , 0.28 to 0.90 ; P=0.02 ) , or progression to stage 3 or higher ( 0.72 ; 95 percent confidence interval , 0.58 to 0.90 ; P=0.003 ) . Multivitamins also result ed in significantly higher CD4 + and CD8 + cell counts and significantly lower viral loads . The effects of receiving vitamin A alone were smaller and for the most part not significantly different from those produced by placebo . Adding vitamin A to the multivitamin regimen reduced the benefit with regard to some of the end points examined . CONCLUSIONS Multivitamin supplements delay the progression of HIV disease and provide an effective , low-cost means of delaying the initiation of antiretroviral therapy in HIV-infected women BACKGROUND Chronic heart failure ( CHF ) is associated with endothelial dysfunction including impaired endothelium-mediated , flow-dependent dilation ( FDD ) . There is evidence for increased radical formation in CHF , raising the possibility that nitric oxide is inactivated by radicals , thereby impairing endothelial function . To test this hypothesis , we determined the effect of the antioxidant vitamin C on FDD in patients with CHF . METHODS AND RESULTS High-resolution ultrasound and Doppler was used to measure radial artery diameter and blood flow in 15 patients with CHF and 8 healthy volunteers .  Vascular effects of vitamin C ( 25 mg/min IA ) and placebo were determined at rest and during reactive hyperemia ( causing endothelium-mediated dilation ) before and after intra-arterial infusion of N-monomethyl-L-arginine ( L-NMMA ) to inhibit endothelial synthesis of nitric oxide . Vitamin C restored FDD in patients with heart failure after acute intra-arterial administration ( 13.2+/-1.7 % versus 8.2+/-1.0 % ; P<.01 ) and after 4 weeks of oral therapy ( 11.9+/-0.9 % versus 8.2+/-1.0 % ; P<.05 ) . In particular , the portion of FDD mediated by nitric oxide ( ie , inhibited by L-NMMA ) was increased after acute as well as after chronic treatment ( CHF baseline : 4.2+/-0.7 % ; acute : 9.1+/-1.3 % ; chronic : 7.3+/-1.2 % ; normal subjects : 8.9+/-0.8 % ; P<.01 ) . CONCLUSIONS Vitamin C improves FDD in patients with CHF as the result of increased availability of nitric oxide . This observation supports the concept that endothelial dysfunction in patients with CHF is , at least in part , due to accelerated degradation of nitric oxide by radicals Primary systemic amyloidosis ( AL ) is a rare disorder characterized by deposition of a monoclonal immunoglobulin light chain or fragment thereof , result ing in dysfunction of the heart , kidney , liver , or nerves . Despite the use of melphalan , prednisone , colchicine , and dimethyl sulfoxide ( DMSO ) , no improvement in median survival has been reported in prospect i ve r and omized studies . We undertook a study of alpha-tocopherol acetate ( vitamin E ) in the treatment of 16 patients with AL because of its reported benefits in animal models of senile and secondary amyloidosis as well as reported benefit in the treatment of secondary amyloidosis in humans . None of the patients showed any objective regression of their disease . The median survival of the entire group was 19.4 months . This survival is not superior to that reported with other agents used in this disease . We conclude that alpha-tocopherol is not a valuable agent in the treatment of AL OBJECTIVES : To identify whether acute lung function effects of ozone can be modulated by antioxidant vitamin supplementation . METHODS : Amateur cyclists ( n = 26 ) were studied in the summer of 1994 in The Netherl and s. Repeated lung function measurements were performed with a rolling seal spirometer after training sessions or competitive races on four to 14 occasions . The cyclists were assigned to two study groups . The supplementation group ( n = 12 ) received antioxidant supplements ( 15 mg beta-carotene , 75 mg vitamin E , and 650 mg vitamin C ) once a day for three months . The control group did not receive supplementation . For each subject , lung function after exercise was regressed on the previous eight hour mean ozone concentration . The individual regression coefficients were pooled for each study group and weighted with the inverse of the variance . RESULTS : The eight hour mean ozone concentration was 101 micrograms/m3 ( 30 to 205 micrograms/m3 ) . For the supplementation group , there was no effect of ozone on FVC , FEV1 , peak expiratory flow ( PEF ) , and maximal mid-expiratory flow ( MMEF ) . For the control group the mean coefficients were negative , except for MMEF . The difference between the groups was 2.08 ( 95 % confidence interval ( 95 % CI ) 1.31 to 2.85 ) ml/microgram/m3 for FVC , 1.66 ( 95 % CI 0.62 to 2.70 ) for FEV1 , 6.83 ( 95 % CI 3.17 to 10.49 ) for PEF , and 0.42 ( 95 % CI -1.38 to 2.22 ) for MMEF . CONCLUSION : The results suggest that antioxidant vitamin supplementation protects against acute effects of ozone on lung function in heavily exercising amateur cyclists Purpose : To evaluate the impact of ascorbic acid of different doses as additional support during luteal phase in infertility treatment by means of a prospect i ve , r and omized , placebo-controlled , group comparative , double-blind study . Methods : Voluntary daily oral intake of either ascorbic acid ( 1 , 5 , or 10 g/day ) or Placebo for 14 days after follicle aspiration for IVF-ET procedure . Data was obtained on 620 cases of women , age < 40 years , undergoing first IVF-embryo transfer cycles in two private out-patient infertility clinics . All women were stimulated by the same protocol . The mean age was 31.73 ( ±4.4 SD ) years . Results : No differences in clinical pregnancy rate and implantation rate were noted in statistical logistic regression analysis between the four intake groups . Conclusions : There was no clinical evidence of any beneficial effect , as defined by main outcome measures , of ascorbic acid on IVF-ET . Our data suggest there is no obvious value of high dosed intake of vitamin C during luteal phase in infertility treatment BACKGROUND Loss of endothelium-derived nitric oxide ( EDNO ) contributes to the clinical expression of coronary artery disease ( CAD ) . Increased oxidative stress has been linked to impaired endothelial vasomotor function in atherosclerosis , and recent studies demonstrated that short-term ascorbic acid treatment improves endothelial function . METHODS AND RESULTS In a r and omized , double-blind , placebo-controlled study , we examined the effects of single-dose ( 2 g PO ) and long-term ( 500 mg/d ) ascorbic acid treatment on EDNO-dependent flow-mediated dilation of the brachial artery in patients with angiographically established CAD .  Flow-mediated dilation was examined by high-resolution vascular ultrasound at baseline , 2 hours after the single dose , and 30 days after long-term treatment in 46 patients with CAD .  Flow-mediated dilation improved from 6.6+/-3.5 % to 10.1+/-5.2 % after single-dose treatment , and the effect was sustained after long-term treatment ( 9 . 0+/-3.7 % ) , whereas flow-mediated dilation was 8.6+/-4.7 % at baseline and remained unchanged after single-dose ( 7.8+/-4.4 % ) and long-term ( 7.9+/-4.5 % ) treatment with placebo ( P=0.005 by repeated- measures ANOVA ) . Plasma ascorbic acid concentrations increased from 41.4+/-12 . 9 to 115.9+/-34.2 micromol/L after single-dose treatment and to 95 . 0+/-36.1 micromol/L after long-term treatment ( P<0.001 ) . CONCLUSIONS In patients with CAD , long-term ascorbic acid treatment has a sustained beneficial effect on EDNO action . Because endothelial dysfunction may contribute to the pathogenesis of cardiovascular events , this study indicates that ascorbic acid treatment may benefit patients with CAD Carotenoids are useful oral sun protectants , and supplementation with high doses of beta-carotene protects against UV-induced erythema formation . We compared the erythema-protective effect of beta-carotene ( 24 mg/d from an algal source ) to that of 24 mg/d of a carotenoid mix consisting of the three main dietary carotenoids , beta-carotene , lutein and lycopene ( 8 mg/d each ) . In a placebo-controlled , parallel study design , volunteers with skin type II ( n = 12 in each group ) received beta-carotene , the carotenoid mix or placebo for 12 wk . Carotenoid levels in serum and skin ( palm of the h and ) , as well as erythema intensity before and 24 h after irradiation with a solar light simulator were measured at baseline and after 6 and 12 wk of treatment . Serum beta-carotene concentration increased three- to fourfold ( P < 0.001 ) in the beta-carotene group , whereas in the mixed carotenoid group , the serum concentration of each of the three carotenoids increased one- to threefold ( P < 0.001 ) . No changes occurred in the control group . The intake of either beta-carotene or a mixture of carotenoids similarly increased total carotenoids in skin from wk 0 to wk 12 . No changes in total carotenoids in skin occurred in the control group . The intensity of erythema 24 h after irradiation was diminished in both groups that received carotenoids and was significantly lower than baseline after 12 wk of supplementation . Long-term supplementation for 12 wk with 24 mg/d of a carotenoid mix supplying similar amounts of beta-carotene , lutein and lycopene ameliorates UV-induced erythema in humans ; the effect is comparable to daily treatment with 24 mg of beta-carotene alone Nine Type I diabetic patients were r and omized to a double-blind therapeutic trial divided into two study periods of 35 d with either 1 g vitamin E/d or a placebo .  Platelet function was estimated at baseline and after treatment from ADP-induced platelet aggregation tests and from generation of oxidative products ( TXB2 , 12 HETE , and malondialdehyde ) after platelet stimulation by 14C arachidonic acid . Platelet function , plasma lipids , and apoproteins were similar before both treatment periods . The vitamin E treatment result ed in 1 ) diminution of platelet aggregation with ADP 2.5 microM ( 56 + /- 4 vs 47 + /- 4 cm2 , p = 0.05 ) and 5 microM ( 70 + /- 5 vs 57 + /- 4 cm2 , p less than 0.01 ) ; 2 ) diminution of malondialdehyde release from platelets ( 6.4 + /- 0.5 vs 5.0 + /- 0.7 nmol/10(9 ) platelets , p less than 0.02 ) ; and 3 ) diminution in the percentage of 14C TXB2 ( 38.1 + /- 2.8 vs 33.3 + /- 3.0 % , p less than 0.05 ) . No significant changes were observed on placebo . Results indicate that high doses of vitamin E diminish ADP-induced platelet aggregation in Type 
    Output:
    
Published by John Wiley & Sons , Ltd Authors ’ conclusions We found no evidence to support antioxidant supplements for primary or secondary prevention .
Vitamin A , beta-carotene , and vitamin E may increase mortality .
Some observational studies also suggest that antioxidant supplements may prolong life , whereas other observational studies demonstrate neutral or harmful effects .
Overall , the antioxidant supplements did not seem to reduce mortality .
In the analyses of the trials with low risk of bias , beta-carotene , vitamin A , and vitamin E significantly increased mortality .
There were no significant differences between the effects of antioxidant supplements in healthy participants ( primary prevention trials ) or participants with various diseases ( secondary prevention trials ) .
R and omised trials with adequate bias control found no significant effect of  vitamin C.  In some of our analyses , selenium seems to reduce mortality .
The current evidence does not support the use of  antioxidant supplements in the general population or in patients with certain diseases .
The evidence on vitamin C and selenium was not conclusive .