***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: ABSTRACT The purpose of this study was to evaluate the effect of docosahexaenoic acid ( DHA ) dietary supplementation on semen quality , fatty acid composition , antioxidant capacity , and DNA fragmentation . In this r and omized , double blind , placebo-controlled , parallel-group study , 74 subjects were recruited and r and omly assigned to either the placebo group ( n=32 ) or to the DHA group ( n=42 ) to consume three 500-mg capsules of oil per day over 10 weeks . The placebo group received 1,500 mg/day of sunflower oil and the DHA group 1,500 mg/day of DHA-enriched oil .  Seminal parameters ( semen volume , sperm concentration , motility , morphology , and vitality ) , total antioxidant capacity , deoxyribonucleic acid fragmentation , and lipid composition were evaluated prior to the treatment and after 10 weeks . Finally , 57 subjects were included in the study with 25 in the  placebo group and 32 in the DHA group . No differences were found in traditional sperm parameters or lipid composition of the sperm membrane after treatment . However , an increase in DHA and Omega-3 fatty acid content in seminal plasma , an improvement in antioxidant status , and a reduction in the percentage of spermatozoa with deoxyribonucleic acid damage were observed in the DHA group after 10 weeks of treatment OBJECTIVE To investigate whether there is an impact of different sources of reactive oxygen species ( ROS ) on sperm functions . DESIGN Prospect i ve study . SETTING Patients at the Center for Dermatology and And rology , Giessen , Germany . PATIENT(S ) Semen collected from 63 r and omly collected patients attending the IVF unit of the University of Giessen , Germany . INTERVENTION(S ) Only patients with nonleukocytospermia were included in this study . MAIN OUTCOME MEASURE(S ) Sperm count and motility before and after sperm separation by swim-up , morphology , DNA fragmentation , and extrinsic ( by leukocytes ) and intrinsic ROS production ( by spermatozoa ) were evaluated . RESULT ( S ) Leukocytes correlated significantly with extrinsic ROS production ( r = 0.576 ) , but markedly less with intrinsic ROS production ( r = 0.296 ) . Sperm count , morphology , and motility in the ejaculate were markedly more affected by extrinsic than by intrinsic ROS . The DNA fragmentation was strongly positively correlated with intrinsic ROS production , whereas this correlation was weaker for extrinsic ROS production . No correlation was found between DNA fragmentation and the number of leukocytes , whereas the correlations with motility in the ejaculate and the motile sperm count after swim-up were highly significant . Moreover , significant differences were observed for extrinsic and intrinsic ROS production between groups of patients having a high ( > or = 1 x 10(6)/mL ) and a low number ( < 1 x 10(6)/mL ) of leukocytes in the ejaculate . CONCLUSION ( S ) The origin of ROS seems to have an influence on the site of the damage . Because leukocyte counts < 1 x 10(6)/mL caused a significant decrease of motility and DNA integrity , the threshold given by the World Health Organization ( WHO ) should be re-evaluated BACKGROUND Most studies examining the use of ICSI for cases of elevated sperm DNA fragmentation report poor pregnancy and implantation rates .  ICSI with testicular sperm sample s has recently been suggested for these cases . Here we test a less invasive approach based on oral antioxidant treatment prior to ICSI with ejaculated spermatozoa . METHODS Thirty-eight men with an elevated ( > or = 15 % ) percentage of DNA-fragmented spermatozoa in the ejaculate were treated with antioxidants ( 1 g vitamin C and 1 g vitamin E daily ) for 2 months after one failed ICSI attempt . In 29 ( 76 % ) of these cases this treatment led to a decrease in the percentage of DNA-fragmented spermatozoa , and a second ICSI attempt was performed . Outcomes of the two attempts were compared . RESULTS No differences in fertilization and cleavage rates or in embryo morphology were found between the ICSI attempts performed before and after the antioxidant treatment . However , a marked improvement of clinical pregnancy ( 48.2 % versus 6.9 % ) and implantation ( 19.6 % versus 2.2 % ) rates was observed after the antioxidant treatment as compared with the pretreatment ICSI outcomes . CONCLUSIONS Oral antioxidant treatment appears to improve ICSI outcomes in those patiens with sperm DNA damage , in whom this treatment reduces the percentage of damaged spermatozoa OBJECTIVE To examine the effects of increased sperm DNA damage in relation to seminal oxidative stress in men with idiopathic and male factor infertility . Prospect i ve study . SETTING S Infertility clinic at a tertiary care academic institution . PATIENT(S ) Ninety-two infertile men with normal female partners . Sixteen fertile donors served as the control group . INTERVENTION(S ) St and ard semen analysis and assessment of levels of seminal oxidative stress . Assisted reproductive techniques in 33 of the 92 patients ( IUI [ n = 19 ] , IVF [ n = 10 ] , and intracytoplasmic sperm injection [ n = 4 ] ) . MAIN OUTCOME MEASURE(S ) Sperm DNA damage by sperm chromatin structure assay . Results were expressed as DNA fragmentation index . RESULT ( S ) Patients were classified as having either idiopathic ( n = 23 ) or male factor infertility ( n = 69 ) . Patients with idiopathic and male factor infertility had significantly higher DNA fragmentation index and oxidative stress compared with the case of fertile donors . A clinical pregnancy was achieved in 9 ( 27 % ) of 33 patients with assisted reproductive techniques . Significantly higher DNA fragmentation index and oxidative stress were found in men who failed to initiate a pregnancy after assisted reproductive techniques ( n = 24 ) , compared with the cases of those who succeeded and of the fertile donors . DNA fragmentation index was correlated positively with oxidative stress ( r = 0.27 ) , and negatively with fertilization ( r = -0.70 ) and embryo quality ( r = -0.70 ) . CONCLUSION ( S ) Sperm DNA damage is significantly increased in men with idiopathic and male factor infertility and in men who failed to initiate a pregnancy after assisted reproductive techniques . Such an increase may be related to high levels of seminal oxidative stress OBJECTIVE To assess semen parameters and couple fecundity as measured by  time to pregnancy ( TTP ) . DESIGN Observational prospect i ve cohort with longitudinal measurement of TTP . SETTING Sixteen Michigan/Texas counties . PATIENT(S ) A total of 501 couples discontinuing contraception were followed for 1 year while trying to conceive ; 473 men ( 94 % ) provided one semen sample , and 80 % provided two sample s. INTERVENTION(S ) None . MAIN OUTCOME MEASURE(S ) Using prospect ively measured TTP , fecundability odds ratios ( FORs ) and 95 % confidence intervals ( CIs ) were estimated for 36 individual semen quality parameters accounting for repeated semen sample s , time off contraception , abstinence , enrollment site , and couples ' ages , body mass indices , and serum cotinine concentrations . RESULT ( S ) In adjusted models , semen quality parameters were associated with significantly shorter TTP as measured by FORs > 1 : percent motility , strict and traditional morphology , sperm head width , elongation factor , and acrosome area . Significantly longer TTPs or FORs < 1 were observed for morphologic categories amorphous and round sperm heads and neck/midpiece abnormalities . No semen quality parameters achieved significance when simultaneously modeling all other significant semen parameters and covariates , except for percent coiled tail when adjusting for sperm concentration ( FOR 0.99 ; 95 % CI 0.99 - 1.00 ) . Male age was consistently associated with reduced couple fecundity ( FOR 0.96 ; 95 % CI 0.93 - 0.99 ) , reflecting a longer TTP across all combined models . Female but not male body mass index also conferred a longer TTP ( FOR 0.98 ; 95 % CI 0.96 - 0.99 ) . CONCLUSION ( S ) Several semen measures were significantly associated with TTP when modeled individually but not jointly and in the context of relevant couple-based covariates OBJECTIVE To examine and compare the effects of density-gradient centrifugation on the integrity of sperm DNA from the semen of both fertile and infertile men . DESIGN Prospect i ve , observational study . SETTING University infertility clinic . PATIENTS Forty-four nonazoospermic , infertile men and nine fertile controls . INTERVENTIONS Semen sample s were processed by density-gradient centrifugation .  Sperm motility and sperm chromatin structure ( evaluated by flow cytometry analysis of acridine orange-treated spermatozoa ) were monitored before and after semen was processed . MAIN OUTCOME MEASURES Sperm motility and DNA integrity . RESULTS Following density-gradient centrifugation , mean sperm motility ( + /-SEM ) improved significantly compared to whole semen in sample s from fertile and infertile men , respectively ( 71 + /- 6 vs. 49 + /- 7 % and 56 + /- 3 vs. 44 + /- 3 % , P<0.05 ) . However , the percentage of sperm with denatured DNA increased compared to whole semen after processing of sample s from infertile ( 25 + /- 3 vs. 15 + /- 2 % , P<0 . 01 ) but not fertile men ( 9 + /- 3 vs. 8 + /- 2 % , P>0.05 ) . CONCLUSIONS Our data indicate that the potential detrimental effect of density-gradient centrifugation on sperm DNA integrity is related to the initial semen quality . These data urge us to examine our current sperm-processing techniques to minimize sperm DNA damage BACKGROUND Couples with unexplained infertility ( UI ) tend to have low fertilization rates with current IVF procedures . Here , we attempted to identify spermatozoa with apoptotic markers in couples with UI and unsuccessful intrauterine insemination ( IUI )  and we investigated the efficiency and benefit of magnetic-activated cell sorting ( MACS ) for sperm preparation in such patients . METHODS Sixty couples with UI and two IUI failures were recruited . The sperm were prepared by conventional density gradient centrifugation ( DGC ) and divided into two aliquots . One aliquot was used as a control and the other was further processed by MACS ( D + M ) . Apoptotic markers were identified using fluorescence-labeled dye and flow cytometry , including externalization of phosphatidylserine ( EPS ) , disrupted mitochondrial membrane potential ( MMP ) and DNA fragmentation . The fertilization potential of prepared spermatozoa was analyzed by basic semen analysis , computer-aided sperm analysis and the induced acrosome reaction test ( IART ) . RESULTS After DGC , spermatozoa showed 18.6 % EPS , 28.3 % disrupted MMP and 13.5 % DNA fragmentation . Numbers of spermatozoa with apoptotic markers were significantly reduced by D + M , versus DGC alone ( P < 0.001 ) . Although the motility of spermatozoa was slightly decreased after MACS , most sperm motion characteristics were not impaired . Interestingly , the IART significantly improved after D + M , versus DGC alone , especially for the couples with a normal hemizona assay ( P < 0.001 ) . CONCLUSIONS The spermatozoa prepared by D + M showed a reduced level of apoptotic markers . Improvement in the IART suggests a high fertilization potential of the processed spermatozoa . The identification of apoptotic markers and use of MACS may be helpful in directing the management plan for patients with UI and multiple IUI failures The primary aim of this study was to determine the effect of oral antioxidant treatment ( 1500 mg of l‐Carnitine ; 60 mg of vitamin C ; 20 mg of coenzyme Q10 ; 10 mg of vitamin E ; 10 mg of zinc ; 200 μg of vitamin B9 ; 50 μg of selenium ; 1 μg of vitamin B12 ) during a time period of 3 months upon the dynamics of sperm DNA fragmentation following varying periods of sperm storage ( 0 h , 2 h , 6 h , 8 h and 24 h ) at 37 ° C in a cohort of 20 infertile patients diagnosed with asthenoteratozoospermia . A secondary objective was to use the sperm chromatin dispersion test ( SCD ) to study antioxidant effects upon a specific sub population of highly DNA de grade d sperm ( DDS ) . Semen parameters and pregnancy rate ( PR ) were also determined . Results showed a significant improvement of DNA integrity at all incubation points ( P < 0.01 ) . The proportion of DDS was also significantly reduced ( P < 0.05 ) . Semen analysis data showed a significant increase in concentration , motility , vitality and morphology parameters . Our results suggest that antioxidant treatment  improves sperm quality not only in terms of key seminal parameters and basal DNA damage , but also helps to maintain DNA integrity . Prior administration of antioxidants could therefore promote better outcomes following assisted reproductive techniques PURPOSE We investigated whether the sperm protamine-1/2 mRNA ratio and DNA 
    Output:
    
Current evidence supports the association between high SDF and poor reproductive outcomes for natural conception and intrauterine insemination .
Although the relationship between high SDF and in vitro fertilisation and intracytoplasmic sperm injection is less clear , the negative implication of high SDF on pregnancy loss is evident .
The predictive value of SDF testing on outcomes of natural pregnancy and assisted reproduction illustrates its value in clinical practice .
Conclusion The significant role of SDF in male factor infertility is supported by current evidence .