***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 
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    Input: The effect of zinc therapy and placebo on sexual function and endocrine status was investigated in a double-blind study of 14 male patients with chronic renal failure on regular haemodialysis .  Zinc chloride was added to the dialysate of 7 patients for 6 weeks , raising the serum zinc concentration by 17 % and placebo was added to the dialysate of the other patients . At the start of the trial 9 patients said they had decreased sexual function . Records of penile erectile activity during sleep confirmed the organic nature of the sexual dysfunction . Plasma testosterone concentrations were low or in the low normal range , basal serum luteinising-hormone levels were raised , and the early luteinising-hormone response to luteinising-hormone-releasing hormone was exaggerated , suggesting primary testicular failure . Zinc administration had no significant effect on any aspect of sexual function assessed by question naire or nocturnal penile tumescence monitoring . Plasma testosterone and basal and stimulated gonadotrophin levels were also unaltered by zinc administration BACKGROUND The aim of this study was to evaluate the safety and effectiveness of sildenafil in male peritoneal dialysis patients with erectile dysfunction . METHODS Sixteen peritoneal dialysis patients were recruited to this prospect i ve , r and omized , double-blind , placebo-controlled , crossover study of sildenafil during a period of 8 weeks . Efficacy was assessed by using the International Index of Erectile Function and a Global Assessment Question . Penile arterial supply was assessed by means of Doppler ultrasound in all patients , and adverse events were recorded . RESULTS Three patients failed to complete the study ( 1 patient received a renal transplant , 1 patient died unrelated to the study , and 1 patient withdrew for personal reasons ) . In the remainder , there was a significant improvement in erectile function with sildenafil compared with placebo ( P = 0.01 ) and the baseline assessment ( P = 0.002 ) . There were also significant improvements in intercourse satisfaction ( P = 0.002 ) and overall satisfaction ( P = 0.005 ) compared with baseline . In response to the Global Assessment Question , 75 % of patients reported improvement in erections . Only 1 adverse event was reported : a headache , which resolved after the third dose of sildenafil . CONCLUSION Sildenafil caused a significant improvement in erectile function in peritoneal dialysis patients , with a success rate at least as high as that reported in other patient groups . The drug was well tolerated , with few adverse events Vardenafil , a novel selective phosphodiesterase type 5 inhibitor , was evaluated in its first large-scale at-home trial . A total of 601 men with mild to severe erectile dysfunction ( ED ) were enrolled in this multi-centre , r and omized , double-blind , placebo-controlled trial of 12 weeks of treatment with either placebo or 5 , 10 and 20 mg of vardenafil . Primary endpoints were Q3 ( vaginal penetration ) and Q4 ( maintenance of erection ) of the International Index of Erectile Function ( IIEF ) . In the intent-to-treat population ( n=580 ) , the changes from baseline for 5 , 10 and 20 mg vardenafil ( 1.2 , 1.3 and 1.5 , respectively ) were all improved ( P<0.001 ) over placebo ( 0.2 ) for Q3 and were similarly improved for Q4 ( 1.4 , 1.5 and 1.7 ) compared to placebo ( 0.5 ) ( P<0.001 ) . All vardenafil doses improved all IIEF domains compared to placebo ( P<0.001 ) . The percentage of successful intercourses was between 71 and 75 % for the three vardenafil doses . For the 20 mg dose , 80 % of the patients experienced improved erections ( GAQ ) compared to 30 % for placebo . Most frequent treatment-emergent adverse events were headache ( 7–15 % ) , flushing ( 10–11 % ) and up to 7 % for dyspepsia or rhinitis . Vardenafil treatment result ed in a high efficacy and low adverse-event profile in a population with mixed ED etiologies BACKGROUND The prevalence of erectile dysfunction ( ED ) among patients with end-stage renal disease ( ESRD ) is not known . METHODS A cross-sectional study was conducted to determine the prevalence of ED among a community-based hemodialysis ( HD ) population using a two-stage cluster r and om sampling design . The presence and severity of ED were assessed among 302 ESRD patients using the self-administered International Index of Erectile Function-5  ( IIEF-5 ) . Logistic regression was used to examine and test associations between ED and other medical conditions . RESULTS The prevalence of any level of ED was 82 % ( 95 % CI , 76 to 87 % ) for all HD subjects . The prevalence of severe ED was 45 % ( CI , 36 to 55 % ) . Subjects younger than 50 years had a prevalence of ED of 63 % ( CI , 53 to 71 % ) , while in subjects 50 years or older , it was 90 % ( CI , 84 to 94 % ) . A multivariable analysis demonstrated increasing age ( 50 to 59 , OR = 2.04 , 95 % CI , 1.3 to 3.1 ; 60 to 69 , OR = 5.5 , 95 % CI , 1.9 to 15.6 ) and diabetes ( OR = 2.0 , 95 % CI , 1.2 to 3.3 ) to be independently associated with the presence of any level of ED . However , neither the subjects ' age nor history of diabetes predicted the severity of ED among subjects with ED . The use of angiotensin-converting enzyme inhibitors ( ACEIs ) was inversely associated with ED ( OR = 0.41 , 95 % CI , 0.17 to 0.98 ) . Poor functional status ( Karnofsky score or the Index of Physical Impairment ) was not associated with ED . CONCLUSIONS ED is extremely prevalent among HD patients . Increasing age , diabetes , and nonuse of ACEIs were associated with higher prevalence of ED . The high prevalence of ED was seen even among patients with good functional status It has been postulated that hyperparahyroidism is in part responsible for  sexual dysfunction in dialyzed patients and that this could improved by 1,25(Oh)2D3 . In a single blind study patients on maintenance hemodialysis were treated after a control period with 1,25 (OH)2D3 and with placebo in r and om order . Sexual performance was assessed with a detailed  semistructured psychiatric interview protocol in 14 and several endocrine parameters were analyzed in 15 patients . Under control conditions sexual function was disturbed in 11/14 patients .  Plasma testosterone was moderately decreased in men , PRL and PTH levels were distinctly elevated in both sexes . 1,25(OH)2D3  raised serum calcium levels significantly from 9.6 to10.6 mg/100 ml ( P < 0.01 ) and lowered PTh from 1.39 to 0.82 ng/ml ( P < 0.01 ) . However , no improvement in sexual function ( such as libido , frequency of intercourse or masturbation ) was found , and apart from a slight rise of testosterone in men and moderate fall of PRl in men and women endocrine parameters remained unchanged . It is concluded that in spite of an improvement of secondary hyperparathyroidism , treatment with 1,25(OH)2D3 for 2 to 4 months was of no value in improving sexual dysfunction in these hemodialysis patients Twenty-four uremic patients on hemodialysis who had never been treated with vitamin E or related drugs and 12 control patients with normal renal function were studied . Hemodialysis patients were r and omly divided into two groups ; 12 were treated with oral vitamin E ( 300 mg/day ) for eight weeks and 12 uremic patients and 12 controls were given placebo .  Serum vitamin E , prolactin , FSH , LH , and free testosterone levels were measured in all patients before and after treatment . After the vitamin E treatment serum prolactin levels were significantly decreased ( 50.8 vs 15.4 ng/ml , p<0.01 ) .  Vitamin E levels were significantly increased ( 1.11 vs 1.22 mg/dl , p<0.05 ) . Serum FSH , LH and free testosterone were not affected . In the other two groups there were no significant changes . These results show that vitamin E treatment lowers prolactin levels in uremic hemodialysis patients . This might be due to inhibition of central prolactin secretion . Vitamin E inhibits pituitary gl and hypertrophy in vitamin E-deficient rats OBJECTIVES To determine the minimal time to successful intercourse after taking sildenafil citrate for erectile dysfunction ( ED ) . METHODS Male patients with ED ( mean age 60 years ; mean ED duration 7.0 years ) who were successfully treated with sildenafil ( 100 mg ) for 2 months or longer were r and omized to sildenafil ( n = 115 ) or placebo ( n = 113 ) for 4 weeks of double-blind treatment . Using a stopwatch , patients recorded the time needed to obtain an erection hard enough for sexual intercourse after taking the study drug at least 2 hours after eating . RESULTS Within 14 and 20 minutes of sildenafil dosing , 35 % and 51 % of sildenafil-treated patients , respectively , versus 22 % and 30 % of placebo-treated patients , respectively , had an erection that led to successful intercourse ( P < 0.05 for both ) . The median time to erection leading to successful intercourse after sildenafil dosing was 36 minutes compared with 141 minutes for placebo . CONCLUSIONS In this study , slightly more than one half of a population of prior sildenafil responders achieved an erection that led to successful sexual intercourse within 20 minutes of sildenafil administration , suggesting that the onset of action of sildenafil can be less than 30 minutes in men with ED Twenty-five men on maintenance hemodialysis commenced a placebo-controlled , double-blind , crossover trial of bromocriptine for  erectile impotence . Eight patients on bromocriptine and one on placebo failed to complete the trial due to side-effects and 2 were withdrawn following renal transplantation .  Libido or the frequency and /or quality of erections or both improved in 11 of the remaining 14 patients during bromocriptine treatment . A significant ( P less than 0.01 ) improvement in patients ' perception of sexual performance occurred on bromocriptine compared with placebo . The 3 patients in whom potency failed to improve had the lowest serum testosterone concentrations . Bromocriptine is usually effective in the management of impotence in males receiving maintenance hemodialysis provided pretreatment serum testosterone is above the lower end of the normal range , but side-effects are relatively common Zinc deficiency may account for the persistence of gonadal dysfunction in a majority of uremic men despite adequate dialysis . Twenty stable patients having hemodialysis three times a week completed a double-blind trial using either 50 mg of elemental zinc as zinc acetate ( 10 patients ) or placebo ( 10 patients ) , orally . At the end of the 6-month study period , a significant increase in the mean ( + /- SE ) plasma zinc ( 75 + /- 2 micrograms/dL to 100 + /- 2 micrograms/dL , p less than 0.001 ) , serum testosterone ( 2.8 + /- 0.3 ng/dL to 5.2 + /- 0.5 ng/mL , p less than 0.001 ) , and sperm count ( 30 + /- 3 million/mL to 63 + /- 5 million/mL , p less than 0.001 ) occurred in the zinc-treated group , but not in those receiving the placebo . The zinc-treated group also had a significant fall in serum luteinizing hormone ( 92 + 2- 10 mIU/mL to 49 + /- 26 mIU/mL , p less than 0.005 ) and follicle stimulating hormone ( 45 + /- 9 mIU/mL to 25 + /- 7 mIU/mL , p less than 0.05 ) , not seen in the placebo group . Patients receiving zinc had an improvement in potency , libido , and frequency of intercourse not found in the placebo group . These results suggest that zinc deficiency is a reversible cause of gonadal dysfunction in patients having regular hemodialysis OBJECTIVES To determine the efficacy of sildenafil for the treatment of erectile dysfunction ( ED ) in a clinical practice setting ; to evaluate the correlation between patient and partner perceptions of treatment outcomes ; and to assess the relation between the severity of ED and response to treatment . METHODS Among the first 100 men to receive sildenafil in a urology practice setting , 74 ( mean + SD age 64+/-11 years ) completed a vali date d sexual function question naire ( International Index of Erectile Function [ IIEF ] ) before and after a 4 to 6-week treatment period . A modified version of the same question naire was independently completed by partners . ED was categorized into a severity class of 
    Output:
    
End-of-treatment testosterone levels were not significantly increased by addition of zinc to dialysate ( two trials , 22 patients , SMD 0.19 ng/dl , 95 % CI -2.12 to 2.50 ) , but oral zinc improved end-of-treatment testosterone levels .
There was no difference in plasma luteinizing and follicle-stimulating hormone level at the end of the study period with zinc therapy .
PDE5i and zinc are promising interventions for treating sexual dysfunction in CKD .