***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: The objective of this study was to assess synergistic antioxidant properties of vitamin C and isoflavones . The design was a placebo-controlled crossover trial : 500 mg vitamin C , 5 mg/kg body weight isoflavones , 500 mg vitamin C plus 5 mg/kg body weight isoflavones , or placebo .  Total lipid peroxides , plasma vitamin C , and blood pressure were measured . Eight of 10 healthy postmenopausal women completed the study . A multiple analysis of variance was performed and least-squares difference post-hoc test utilized to determine where differences occurred . Significance was defined as P < .05 . There was a significant reduction in total lipid peroxides between baseline and isoflavone treatments ( 3.22+/-0.72 vs 2.47+/-0.82 nmol/mL , P < .05 ) . Mean systolic blood pressure was higher during isoflavone intervention than placebo ( 117+/-14 vs 125+/-15 mm Hg , P= .042 ) . Supplementation with vitamin C and isoflavones did not produce a synergistic antioxidant effect . A slight but significant increase in systolic blood pressure occurred with isoflavone supplementation . A larger study should be conducted to fully explore the potential interactions between these antioxidants Pathological formation of reactive oxygen species within the coronary circulation has been hypothesized to mediate some clinical manifestations of ischemic heart disease ( IHD ) by interfering with physiological regulation of coronary tone . To determine the degree to which coronary tone responds to acute changes in ambient levels of oxidants and antioxidants in vivo in a clinical setting , we measured the effect of an acute oxidative stress ( breathing 100 % oxygen ) on coronary capacitance artery diameter ( quantitative angiography ) and blood flow velocity through the coronary microcirculation ( intracoronary Doppler ultrasonography ) before and after treatment with the antioxidant vitamin C ( 3-g intravenous infusion ) in 12 IHD patients undergoing a clinical coronary interventional procedure . Relative to room air breathing , 100 % oxygen breathing promptly reduced coronary blood flow velocity by 20 % and increased coronary resistance by 23 % , without significantly changing the diameter of capacitance arteries .  Vitamin C administration promptly restored coronary flow velocity and resistance to a slightly suprabasal level , and it prevented the reinduction of coronary constriction with rechallenge with 100 % oxygen . This suggests that acute oxidative stress produces prompt and substantial changes in coronary resistance and blood flow in a clinical setting in patients with IHD , and it suggests that these changes are mediated by vitamin C-quenchable substances acting on the coronary microcirculation . This observation may have relevance for clinical practice AIM The influence of oxidative stress ( OS ) and inflammation on up-regulation of blood pressure ( BP ) has been well established . Peripheral polymorphonuclear leukocytes ( PMNLs ) are primed in essential hypertension ( EH ) patients , releasing uncontrolled superoxide anion contributing to OS in these patients . PMNL priming correlates with PMNL intracellular calcium [Ca2+]i . Previous studies have shown that treatment by calcium channel blockers lowers BP , OS and inflammation . In the same time , there are some trials showing down regulation influence of ' ' anti-oxidative ' ' drugs as Vitamin E and C to inflammation and OS . The data of clinical significance of anti-oxidative drugs to BP is controversial . The aim of this paper was to evaluate the benefit of combined treatment by calcium channel blockers ( Lercanidipine ) and antioxidative drugs ( Vitamins C and E ) on BP and on parameters of inflammation and OS . METHODS Sixteen new diagnosed patients with mild to moderate BP were sample d to 2 groups after r and omization by age , sex , and mean arterial pressure ( MAP ) , cholesterol and glucose level . The first group was treated by Lercanidip-ine only , the second group by combination of Lercanidipine and antioxidative drugs both for 6 months . PMNL priming was assessed by the rate of superoxide release from separated , phorbol ester-stimulated PMNLs and by PMNL-CD11b level . Inflammation was reflected by plasma C-reactive protein ( CRP ) and albumin levels , white blood cells ( WBC ) and PMNL counts and by PMNL apoptosis . RESULTS In both groups , BP decreased after 6 months of treatment , and in a more pronounced manner following the combined treatment . In both groups PMNL priming parameters remained unchanged after 6 months of treatment , with transient differences between the two groups during the experimental period . In both groups inflammation parameters remained unchanged after 6 months of treatment , without difference between the two groups , except a pronounced decrease in the percentage of apoptotic PMNLs in the combined treatment group . CONCLUSION Our trial shows a clinical benefit combining calcium channel blockers treatment with antioxidants in BP treatment , although it did not reveal significant influence of complementation of antioxidants to calcium channel blockers on OS and inflammation parameters . Additional clinical and laboratory investigations are needed to clear this issue . Conflicting data are reported on the influence of vitamins E and C on OS and inflammation together with controversy regarding anti-oxidative drugs and their effect on BP 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 Abstract . Rationale : Physiological responses to stress are considered disruptive to health . High-dose ascorbic acid has reduced indices of stress in laboratory animals . Methods : We conducted a r and omized double-blind , placebo-controlled 14-day trial of sustained-release ascorbic acid ( 60 healthy young adults ; 3 × 1000 mg/day Cetebe ) and placebo ( 60 healthy young adults ) for reduction of blood pressure , cortisol , and subjective response to acute psychological stress ( Trier Social Stress Test , TSST , consisting of public speaking and mental arithmetic ) . Six subjects from each group were excluded . Results : Compared to the placebo group , the ascorbic acid group had less systolic blood pressure ( an increase of 23 versus 31 mmHg ) , diastolic blood pressure , and subjective stress responses to the TSST ; and also had faster salivary cortisol recovery ( but not smaller overall cortisol response ) . Cortisol response to 1 µg ACTH , and reported side-effects during the trial did not differ between groups . Plasma ascorbic acid level at the end of the trial but not pre-trial was associated with reduced stress reactivity of systolic blood pressure , diastolic blood pressure , and subjective stress , and with greater salivary cortisol recovery . Conclusions : Treatment with high-dose sustained-release ascorbic acid palliates blood pressure , cortisol , and subjective response to acute psychological stress . These effects are not attributable to modification of adrenal responsiveness Twelve cigarette smoking and 10 nonsmoking healthy human volunteers , 25 to 38 yr of age , performed lung function and treadmill performance tests over two periods of 3 wk duration while taking either ascorbic acid ( 300 mg daily ) or placebo tablets in a cross-over design . The two exercise periods were separated by a one-month inactive phase . Tablets were administered in a r and om , double-blind manner . Plasma vitamin C levels were significantly increased after 3 wk of ascorbic acid supplementation in both smokers and nonsmokers as compared to initial levels in the same subjects . No differences between ascorbic acid and placebo treatments of smokers and nonsmokers were observed for 1-s forced expiratory volume , forced vital capacity , 1-s forced expiratory percent , resting heart rate , resting and postexercise systolic and diastolic blood pressures , treadmill workload , postexercise blood lactic acid , and ventilation measurements . The postexercise systolic blood pressure values of the nonsmokers were lower , although not quite significantly , after the ascorbic acid treatment than after the placebo . The 300-mg ascorbic acid supplement appeared to have little effect on the lung function and physical performance of healthy smoking and nonsmoking males OBJECTIVE To investigate the effect of supplementation with multivitamin and mineral on blood pressure and C-reactive protein ( CRP ) in obese women with increased cardiovascular disease risk as having hypertension , hyperglycemia or hyperlipemia . SUBJECTS AND METHODS 128 obese Chinese women aged 18 - 55 years with increased cardiovascular disease risk participated in a 26-week r and omized , double-blind , placebo-controlled trial . Subjects were r and omized to four groups , and received either one tablet of high-dose multivitamin and mineral supplement ( MMS ) , or one tablet of low-dose MMS ( Low MMS ) , or calcium 162 mg ( Calcium ) or identical placebo ( Placebo ) daily during the study . Diastolic blood pressure ( DBP ) , systolic blood pressure ( SBP ) and serum concentrations of CRP were measured at baseline and end-trial . RESULTS At baseline , the subjects had an average age of 42.0+/-7.1 years and BMI of 30.9+/-2.8 kg/m2 . There were no significant differences between the four groups in baseline characteristics . One hundred and seventeen subjects completed the study . After 26-week supplementation , both SBP and DBP were significantly lower in the MMS group compared to the placebo group ( p < 0.05 ) . There was also a non-significant trend of lower DBP at 26-week in the MMS and calcium groups compared to baseline ( p < 0.08 ) . At 26-week , the MMS group also had significantly lower serum concentrations of CRP compared with that of baseline and the placebo group ( p < 0.05 ) . CONCLUSIONS Our results showed that supplementation with adequate multivitamin and mineral supplement could reduce blood pressure and serum CRP in obese women with increased cardiovascular disease risk Abstract —In a double-blinded r and omized controlled trial , we investigated the long-term effect of vitamin C supplementation on blood pressure . A total of 439 Japanese subjects with atrophic gastritis initially participated in the trial using vitamin C and & bgr;-carotene to prevent gastric cancer . Before and on early termination of & bgr;-carotene supplementation , 134 subjects dropped out of this trial , whereas 120 and 124 subjects took the vitamin C supplement daily at either 50 mg or 500 mg , respectively , for 5 years . Before supplementation , neither systolic nor diastolic blood pressure was significantly related with the serum vitamin C concentration . This relationship was unchanged after adjustment for age , body mass index , and alcohol intake or after stratification by gender . After 5 years , systolic blood pressure significantly increased in groups , regardless of vitamin C dose , compared with baseline . Systolic blood pressure in the high-dose group ( 500 mg daily ) increased from 125.4 to 131.7 mm Hg ( 5.88 mm Hg increase ; 95 % confidence interval [ CI ] , 3.11 to 8.65 ) . This value was similar with that of the low-dose group ( 5.73 mm Hg increase ; 95 % CI , 2.62 to 8.83 ) and of the dropout group ( 4.52 mm Hg increase ; 95 % CI , 1.26 to 7.77 ) . There was no difference in change of diastolic blood pressure among the 3 groups . 
    Output:
    
After the inclusion of 9 trials with imputed BP effects , BP effects were attenuated but remained significant .
In short-term trials , vitamin C supplementation reduced SBP and DBP .