Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Sperm Count”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 829 records · Page 46Linked to original sources
PubMed2001

Cryptorchidism: aspects of fertility and neoplasms. A study including data of 1,335 consecutive boys who underwent testicular biopsy simultaneously with surgery for cryptorchidism.

PURPOSE: An attempt to make a rational strategy for treatment of cryptorchidism. MATERIALS AND METHODS: 1,335 cryptorchid boys with biopsy at surgery (1,638 specimens). We studied: frequency of no germ cells in biopsies from 698 patients <12 years at surgery; fertility potential of 140 patients who were now adults, and apperance of testicular neoplasia in all biopsies. RESULTS: Lack of germ cells appeared from 18 months. The frequency increased with increasing age. It appeared in 30% (61/202) bilateral, and 18% (88/496) unilateral cases. In men who had undergone bilateral or unilateral orchiopexy, respectively, there was normal sperm count in 19% (14/75) and 83% (54/65), and infertility was suspected in 56% (42/75) and 8% (5/65) (FE, p < 0.00005, p < 0.00005), respectively. The lowest, the mean, and the highest age-matched spermatogonia count per tubule at orchiopexy was associated with sperm count (Spearman test, p < 0.0001, p < 0.005, p < 0.05). Isolated, this was demonstrated for the 75 formerly bilateral (Spearman, p < 0.0001, p < 0.0001, p < 0.0001), but not the 65 formerly unilateral cases (Spearman, p = 1.0). No germ cells at orchiopexy was associated with suspected infertility. Risk was 78-100% in bilateral (dependent on one or both testes affected), and 33% in unilateral cryptorchidism. There was one invasive germ cell tumor, six cases of carcinoma in situ testis, and one Sertoli cell tumor. Three neoplasms were diagnosed in intra-abdominal testes, four in boys with abnormal external genitalia, and two in boys with known abnormal karyotype. Risk of neoplasia was 5% (7/150) in patients with intra-abdominal testis, abnormal external genitalia or diagnosed abnormal karyotype, versus 0% (0/1,185) in patients without these characteristics (FE, p < 0.00005). CONCLUSION: We recommend surgery for cryptorchidism before 15-18 months of age because: (a) lack of germ cells is very rare before, and (b) lack of germ cells is associated with subsequent risk of infertility. At primary surgery for cryptorchidism, we recommend examination for testicular neoplasia in cases of intra-abdominal testis, abnormal external genitalia or known abnormal karyotype.

Carcinoma in Situ↗
PubMed2001

Spermatogenic failure in male mice with four sex chromosomes.

There is accumulating evidence that meiosis, like mitosis, is monitored by a number of checkpoints. In mammals, the presence of asynapsed chromosomes at pachytene triggers a checkpoint (the pachytene or synapsis checkpoint) that removes cells via a p53-independent apoptotic pathway. In the special case of the sex bivalent in males, it is pseudoautosomal region (PAR) asynapsis that triggers the checkpoint. In male mice with three sex chromosomes (XYY or XYY(*X)) some pachytene spermatocytes achieve full (trivalent) PAR synapsis, but in many cells one sex chromosome remains as a univalent, thus triggering the checkpoint. Sperm counts in these males have been shown to be positively correlated with trivalent frequencies. In the present study sperm production and levels of sex chromosome synapsis were studied in mice with four sex chromosomes (XYYY(*X)) and XYY(*X)Y(*X)). These mice proved to be more severely affected than XYY or XYY(*X) mice. Nevertheless, pachytene synaptonemal complex analysis revealed that full PAR synapsis was achieved through the formation of radial quadrivalents or through the formation of two sex bivalents in 21%-49% of cells analysed. Given these levels of full PAR synapsis, the sperm counts were consistently lower than would have been predicted from the relationship between levels of PAR synapsis and sperm counts in mice with three sex chromosomes. It has been suggested that the inactivation of the asynapsed non-PAR X and Y axes of the XY bivalent of normal males (MSCI), which occurs during meiotic prophase, may be driven by Xist transcripts originating from the X. If this is the case, the non-PAR Y axes of YY and YY(*X) bivalents would fail to undergo MSCI. This could be cell lethal, either because of 'inappropriate' Y gene expression, or because the non-PAR Y axis may now trigger the synapsis checkpoint.

Animals↗
PubMed2000

Comparison of results and complications of high ligation surgery and microsurgical high inguinal varicocelectomy in the treatment of varicocele.

OBJECTIVES: To prospectively compare sperm parameters, pregnancy and recurrence rates, and complications after randomized high ligation surgery versus microsurgical high inguinal varicocelectomy (MHIV). METHODS: Varicocele was diagnosed by physical examination and color Doppler ultrasound in 468 patients who underwent one of two procedures: high ligation surgery (n = 232) or MHIV (n = 236). The high ligation surgery was left unilateral in 142 and bilateral in 90. The MHIV was left unilateral in 128 and bilateral in 108. The patients were postoperatively evaluated by spermiograms and physical examination. The pregnancy rate was monitored for 2 years. RESULTS: One year after surgery, 34.05% in the high ligation group and 46.61% in the MHIV group had a more than 50% increase in their total motile sperm count (P = 0.000). The increase in sperm count was not statistically different between the two groups (P = 0.1), but the difference in the increase in sperm motility in the MHIV group was statistically significant (P = 0.000). Pregnancy rates at the end of 2 years reached 33.57% in the high ligation group and 42.85% in the MHIV group, not a statistically significant difference (P = 0.0571). The postoperative recurrence as detected by physical examination was markedly different between the two techniques. The recurrence rate was 15.51% in the high ligation group and 2.11% in the MHIV group (P = 0.000). Also, the incidence of postoperative hydrocele was significantly different between the two groups (9.09% in the high ligation group and 0.69% in the MHIV group; P = 0.000). CONCLUSIONS: MHIV has lower recurrence and hydrocele rates, a higher increase in sperm motility, and results in higher pregnancy rates. Therefore, it should be the preferred technique for varicocelectomy.

Adult↗
PubMedDate not supplied

Semen analysis in men from Mérida, Venezuela, over a 15-year period.

To determine the possible changes in semen quality of Venezuelan men from 1981 to 1995, a retrospective analysis of semen volume and sperm concentrations was carried out for 2313 men from infertile couples. According to the sperm counts the sample was categorized in four groups: A, 0 sperm; B, <20 x 10(6) sperm/mL; C, 20-200 x 10(6) sperm/mL; D, 2200 x 10(6) sperm/mL. The percentage of men in each group was 9.1, 18.8, 63. 1, and 9.0%, respectively. The frequency of azoospermia and oligozoospermia (groups A and B) did not change over the last 15 years. On the contrary, the frequency showed a significant increase in group C and a decrease in group D. The range of the means of semen volume was 2.6-3.6 mL, linear regression analysis did not show a decrease in seminal fluid volume over time. The range of the means of sperm concentrations were 6.2-12.0 x 10(6) sperm/mL, 73-100 x 10(6) sperm/mL), and 230-340 sperm x 10(6)/mL in groups B, C, and D, respectively. Linear regression analysis revealed a significant reduction in the means of sperm concentrations only in group D. Excluding the azoospermic group, the analysis of pooled data (B + C + D), did not show a significant change in the means of sperm density throughout time. In the semen samples with sperm counts below 200 x 10(6)/mL the means of sperm concentration did not change in the 15-year period of observation.

Adult↗
PubMed2002

Dendritic cell infiltration in a patient with seminomatous germ cell tumor of the testis: is there a relationship with infertility and tumor stage?

PURPOSE: Inflammatory cells, such as dendritic cells, are considered to trigger the antitumoral immune response against tumors, such as testicular cancer. Male infertility associated with cancer may be due to endocrine or immunological factors. We investigated possible associations of antigen expression with dendritic cells, histiocytic cells and seminoma stage as well as with impaired spermatogenesis. MATERIALS AND METHODS: From 1992 to 1999, 30 patients with seminoma underwent orchiectomy at our center, including 14 who underwent spermiography before orchiectomy. Streptavidin-biotin immunostaining was performed on paraffin -embedded tumor specimens using antibodies against protein S-100 for dendritic cells and CD68-KP1 antigen. RESULTS: Light infiltration by less than 20 dendritic cells and less than 103 CD68+ cells was associated with tumor size greater than 1.5 cm. in 75% and 80% of patients, respectively. Strong infiltration by greater than 20 dendritic cells and greater than 103 CD68+ cells was associated with negative lymph nodes in 86% of patients. Slight infiltration by dendritic cells was observed in 71% of patients with a sperm count of greater than 8.6 million per ml. and in 100% with more than 45% motile sperm (p not significant and 0.02, respectively). Necrospermia increased with dendritic and CD68+ cell infiltration. No association was noted among preoperative serum tumor marker levels, the sperm count and immunostaining. CONCLUSIONS: Sperm autoimmunity is a plausible mechanism of infertility in men with germ cell tumors. Dendritic cells may induce antitumor cell cytotoxic reactions, but may also be cytotoxic to sperm cells or lead to inhibited spermatogenesis. Further studies focusing on tumor rejection antigen and the cloning of specific cytotoxic T lymphocyte against gametes are required to confirm these finding.

Adult↗
PubMed1997

The performance of 10 different methods for the estimation of sperm concentration.

OBJECTIVE: To evaluate the performance of different methods of sperm counting using latex beads and sperm suspension. DESIGN: A quality-control study. SETTING: University-based andrology laboratory. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Counting latex beads six times in two standard suspensions using 10 methods and counting spermatozoa with 4 methods. RESULT(S): When air-displacement pipettes were used, the disposable chambers Standard Count (Leja, Amsterdam, Holland), Cellvision (Anthos-ec, Heerhugowaard, The Netherlands), and Cell Vu (Fertility Technologies, Inc. Natick, MA) showed small variation and correct estimation of bead concentration. All the reusable chambers gave relatively large variability, with tendency to underestimate (improved Neubauer; Hawksley, Lancing, United Kingdom) or to overestimate the bead concentration. The use of plunger-displacement pipettes resulted in an overestimation of bead concentration in medium but not in seminal plasma. Counting the sperm suspension using plunger-displacement pipettes indicated that the Bürker hemocytometer overestimated concentration relative to that obtained by Cellvision and Makler Counting Chambers (Sefi Medical Instruments, Haifa, Israel) and that the improved Neubauer presented the lowest variability (7.1%). CONCLUSION(S): The improved Neubauer hemocytometer is the standard for sperm counting, though disposable chambers give reliable results as well. If beads are used to evaluate the accuracy of counting chambers, it is recommended to dilute them with seminal plasma.

False Positive Reactions↗
PubMed1982

Pituitary and testicular functions in sexually mature rhesus monkeys under high-dose LRH-agonist treatment.

Treatment with high doses of LRH-agonists leads to a down-regulation of testicular LH/hCG receptors and is accompanied by a suppression of spermatogenesis in some laboratory animals. In order to test whether this may provide an approach to male fertility control, 4 adult rhesus monkeys were treated with very high doses of LRH-agonist, D-Ser(TBu)6-LHR-ethylamide (100 micrograms daily) for 10 weeks during the breeding season. There was a decrease in testicular volume after 3 weeks of treatment. Serum LH and testosterone levels were suppressed. Sperm counts were stimulated during the first 6 weeks of treatment. At the end of treatment sperm counts, although lower, were still in the normal range. The chronic treatment schedule resulted in a decrease in pituitary responsiveness to an acute challenge with 4 micrograms agonist iv, indicating a desensitization of the pituitary. However, the testosterone response remained unchanged. This study using extremely high doses of the agonist indicates that, compared to the rat, male primates are far more resistant to the suppressive effects of LRH-agonists.

Animals↗
PubMed1990

The effect of L-acetylcarnitine on some reproductive functions in the oligoasthenospermic rat.

The effect of L-acetylcarnitine (LAC) on some parameters of male reproductive function was studied on rats made oligoasthenospermic with dibromochloropropane (DBCP). DBCP depresses sperm count and motility. After one injection of the drug, LAC induces a recovery of both sperm count and motility but after two injections it is ineffective. This effect is also shown visually by microscopic examination of seminiferous tubules. Among the enzymatic activities evaluated as biochemical markers of testicular function both lactate dehydrogenase and NADPH-cytochrome P 450-reductase increased significantly (P less than 0.05) after treatment with LAC in normal rats. LAC also stimulates testosterone production. It is suggested that LAC may affect testicular function.

Acetylcarnitine↗
PubMed1998

Contrasting associations of blood and semen lead concentrations with semen quality among lead smelter workers.

While blood lead concentration has been inversely associated with indicators of reproductive health in occupationally exposed male workers, the utility of lead concentration in semen as an indicator of lead exposure to the male reproductive system has not been fully explored. Blood and semen lead concentrations from 81 lead smelter workers were examined in relation to semen quality and endocrine function parameters. Mean blood and semen lead concentrations were 22.8 micrograms/dl (range 5-58) and 1.9 micrograms/dl (range 0.1-17.6), respectively. Total sperm count and concentration decreased with increasing blood lead concentration; p for trend was 0.003 and 0.009, respectively. Semen lead concentration was inversely related to total sperm count (p = 0.05), ejaculate volume (p = 0.001), and serum testosterone (p = 0.004), but not to sperm concentration. The association between semen lead concentration and total sperm count was eliminated when volume was included in the model. Blood lead concentration was more consistently associated with indicators of sperm production than was semen lead. In contrast, semen lead concentration was negatively associated with circulating testosterone concentrations. Our findings indicate that measurement of semen lead may not be a valuable adjunct to conventional blood lead monitoring for investigations of male reproductive system toxicity.

Adult↗
PubMed2001

Characterization of semen collected from beagles and captive Japanese black bears (Ursus thibetanus japonicus).

This study characterized semen collected from the Japanese black bear, Ursus thibetanus aponicus, to provide information on semen cryopreservation for artificial breeding. Preliminary studies using a beagle dog as the model species showed that sperm concentration and total sperm count were lower in semen collected by electroejaculation than in semen collected by digital manipulation, but that sperm motility, viability and morphology were similar. Characterization of semen obtained from Japanese black bears by electroejaculation under general anesthesia revealed that semen volume and total number of spermatozoa collected were lower; but that sperm concentration, motility, viability and morphology were equivalent to those reported in other ursids. When semen was collected via a catheter inserted into the urethra during the stimulation for ejaculation, the sperm concentration, total sperm count and motility were relatively higher than when semen was collected directly in a test tube. Specific normal semen characteristics (mean +/- SEM) were pH, 7.6 +/- 0.0; volume, 0.212 +/- 0.038 mL; sperm concentration, 361 +/- 100 x 10(6)/mL; total sperm count, 84.0 +/- 32.2 x 106; +++ motility, 30 +/- 5%; motility, 77 +/- 3%; viability 77 +/- 2%; and abnormal morphology, 11+/- 2%. These results suggest that semen can be collected from Japanese black bears by electroejaculation.

Animals↗
PubMed1978

[The effect of varicocele on male fertility with particular consideration of progressive motility (author's transl)].

Two-hundred patients with varicocele were examined for fertility, which was found to have diminished in 75% of the cases because of a decreased sperm count (less than 40 million/ml); 40% of these, the largest group (categorized only with regard to oligospermia), had a sperm count of 21--40 million/ml. The most remarkable finding was restrained fertility in 90% of the cases because of decreased progressive motility (speed of forward progression). Here, the largest group (nearly 50%) was in the category of 21--30%. Decreased progressive motility was mostly combined with a diminished sperm count to an oligoasthenospermia. In 20% of the cases, however, fertility was restrained only by decreased progressive motility in the sense of an asthenospermia. The first effect, due to varicocele, is seen in decreased progressive motility. However, because spermatozoa acquire their progressive motility by means of maturation in the epididymis, the varicocele causes the first damage to the epididymis.

Cell Count↗
PubMed1990

Testicular function after chemotherapy for osteosarcoma.

Testicular volume, sperm count and four hormones were measured in 18 patients 1-13 years after chemotherapy for osteosarcoma. The testicles were small in 13 patients. 17 patients gave semen samples: 10 were azoospermic and 2 were oligozoospermic. Testicular volume and sperm count were possibly associated with the type of chemotherapy. Of the 7 patients who had received cisplatin-containing chemotherapy, 6 had small testes and azoospermia; 1 was oligozoospermic with normal-sized testes. In 3 of the 11 patients whose chemotherapy had not included cisplatin, testicular size and sperm count were normal.

Adolescent↗
PubMedDate not supplied

The effect of methoxychlor on the epididymal antioxidant system of adult rats.

Methoxychlor is widely used as a pesticide in many countries and has been shown to induce reproductive abnormalities in male rats, causing reduced fertility. The mechanism of action of methoxychlor on the male reproductive system is not clear. In the present study we investigated whether administration of methoxychlor induces oxidative stress in the epididymis and epididymal sperm of adult rats. Methoxychlor (50, 100, or 200 mg/kg body weight/day) was administered orally for 1, 4, or 7 days. The animals were killed using anesthetic ether 24 h after of the last treatment. Epididymal sperm were collected by cutting the epididymis into small pieces in Ham's F-12 medium at 35 degrees C. The body weight and weights of the testis, liver, and kidney did not show any significant changes in the methoxychlor-treated rats. The weight of the epididymis, seminal vesicles, and ventral prostate as well as epididymal sperm counts decreased after 50, 100, or 200 mg/kg/day for 7 days but remained unchanged after shorter courses of treatment. Epididymal sperm motility was decreased in a dose-dependent manner in the animals treated with methoxychlor for 4 or 7 days. The activities of the antioxidant enzymes superoxide dismutase, catalase, glutathione reductase, and glutathione peroxidase were decreased while the levels of hydrogen peroxide and lipid peroxidation were increased in the epididymal sperm as well as in the caput, corpus, and cauda epididymis after 4 or 7 days of treatment. The activities of superoxide dismutase decreased while the levels of lipid peroxidation increased in the liver but not in the kidney in all groups. Co-administration of the antioxidant vitamin E (20 mg/kg body weight/ day) to the 200 mg/kg/d methoxychlor-treated rats for 7 days prevented significant changes in the antioxidant systems in the epididymis and epididymal sperm and prevented alterations in sperm counts and motility. The results indicated that methoxychlor induces oxidative stress in the epididymis and epididymal sperm by decreasing antioxidant enzymes, possibly by inducing reactive oxygen species. In conclusion the adverse effect of methoxychlor on the male reproduction could be due to induction of oxidative stress.

Animals↗
PubMed2002

Oxidative stress associated DNA damage in testis of mice: induction of abnormal sperms and effects on fertility.

Our previous work has shown that prooxidant treatment has the propensity to induce male-mediated dominant lethal (DL) type mutations in mice. The present investigation is aimed to understand the effect of oxidative stress (OS) on DNA damage in testis, epididymal sperms and its propensity to induce sperm head abnormalities as well as its implications on male fertility in mice. Initially, employing two organic hydroperoxides, (t-butyl hydroperoxide, t-bHP and cumene hydroperoxide, cHP) as model prooxidants, induction of oxidative stress was ascertained following single/multiple sublethal doses. Further, the multiple exposure model was utilized to characterize effects on testicular weights, histoarchitecture, caudal sperm counts, lipid peroxidation, DNA damage and frequency of abnormal sperms. Single sublethal doses (1/20, 1/10 and 1/5 LD(50)) of t-bHP and cHP administered (i.p.) to adult mice resulted in only a marginal increase (20% at the highest dosage) in testicular MDA levels. However, multiple doses (1/10 and 1/5 LD(50) per day for 5 days) induced marked OS in testis and epididymal sperms as evidenced by a marked increase in lipid peroxidation at 24h after the last dose. This was associated with significant increase in the DNA damage (FADU assay) in the testicular tissue. While caudal sperm counts determined at all sampling weeks showed no treatment related alterations, analysis for head abnormalities revealed nearly 2-3-fold increase in the percent abnormal sperms among the hydroperoxide treated mice during the first 3 weeks. Furthermore, mating of prooxidant treated males sequentially for a period of 5 weeks with untreated females resulted in a significant reduction in average pup number per litter during the first 3 weeks. These results suggest that oxidative stress in testicular milieu is associated with DNA damage and produces higher frequency of abnormal sperms with significant effect on male fertility.

Animals↗
PubMed1984

Laboratory tests for human male reproductive risk assessment.

The criteria for reproductive test selection which were set forth in the beginning of this chapter required that the tests be objective, technically sound, biologically stable, sensitive and feasible. All of the tests which have been discussed can generate objective quantitative data (Table 1). Testicular tonometry appears to be a technically sound procedure which measures a biologically stable parameter, although this remains to be proven. Sperm counts are definitely not a biologically stable parameter. There is insufficient information to judge the biological stability of data obtained from sperm cervical mucus interaction. Data from a number of laboratories suggest that the zona-free hamster egg assay gives stable results when repeated with the same donor, and the tests as performed in specialized laboratories are technically sound at the present time. However, the number of laboratories which can perform the assay is limited. Sensitivity to early toxicity is a very important criterion for test selection. Physical examination does not meet this criterion, endocrine studies do not, and sperm counts do not. Not enough information is currently available to determine the sensitivity of sperm motility assessment. Sperm morphology assessment may be the most sensitive early indicator of reproductive toxicity which is currently available. There is a large body of clinical and basic science literature which suggests that sperm morphology may reflect acute stress effects on the testes. The feasibility of these tests vary. Sperm motility may be feasible only in longitudinal studies in which the video equipment can be set up in a laboratory which is doing repeated assessments. Sperm morphology assessment does not require any specialized equipment in the field. Studies of sperm cervical mucus interaction, for the reasons already stated, remain non-feasible at this time. Tests of sperm-egg interaction are probably feasible if spermatozoa can be shipped to a specialized laboratory for assessment. Thus, there are now a number of new tests for male reproductive function which are available, and which are practical. It is time for this technology to be transferred from the basic science laboratory for application in human reproductive risk assessment.

Cervix Mucus↗
PubMed2003

Effect of alcoholic extract of Lepidium meyenii (Maca) on testicular function in male rats.

AIM: To evaluate the effect of the alcoholic extract of Lepidium meyenii (Maca) on the spermatogenesis in male rats. METHODS: In Holtzman rats, Maca alcoholic extract (5 %) was given by oral route at doses of 48 mg/day or 96 mg/day for 7 days, 14 days and 21 days. Testicular function was assessed by measurements of lengths of different stages of seminiferous epithelia and by epididymal sperm count. RESULTS: Ethanolic extract of Maca increased the length of stages IX-XI of seminiferous epithelium at treatment day 7, day 14 and day 21. Progression of spermatogenesis was evident only after day 21 when lengths of stages XII-XIV of seminiferous epithelium were increased; at day 7 and day 14, no important change in spermatogenesis was observed. Epididymal sperm count was increased with 48 mg/day at all times. With 96 mg/day an increase in sperm count was observed at day 7, but it was reduced at day 14 and day 21 of treatment. Serum testosterone levels were not affected. CONCLUSION: The alcoholic extract of Maca activates onset ant progression of spermatogenesis at 48 mg/day or 96 mg/day in rats.

Animals↗
PubMed1998

[The analysis of the sperm parameters in view of its concentration and motility in relation to men's age and occupation].

OBJECTIVE: To evaluate chosen sperm parameters (concentration and progressive motility) in relation to men's age and occupation. MATERIAL AND METHODS: Retrospective study of laboratory records containing semen analysis results (n = 473, 1995-1997) of patients attending local andrology lab. Linear regression analyses was applied to co-related the age of the patients with the sperm concentration and progressive motility. Mean sperm counts and percentage of motile spermatozoa were compared in the general population vs. car drivers and soldiers. RESULTS: Sperm characteristics were not associated with the age of men. No differences between the general population, drivers and soldiers were found. The values of the mean sperm counts and percentage of motilile spermatozoa were higher than the cut-off values of the WHO. CONCLUSION: The data show no evidence of deterioration in sperm quality in relation to the age and occupation of patients.

Adult↗
PubMed1988

Sialyl transferase in human semen.

The activity of the enzyme sialyl transferase, which is responsible for the transfer of sialic acid, has been examined in the following human seminal plasma: (1) originating from semen with sperm counts above 30 X 10(6)/ml and exhibiting normal values of other andrological parameters; (2) from semen with sperm counts below 25 X 10(6)/ml and with other andrological parameters of poor quality; (3) from semen devoid of sperm. Additionally, enzyme activity was examined in fractionated (split) semen. The activity in plasma based on measurement of radioactivity incorporated into asialofetuin, following incubation in the presence of 14C sialic acid, was expressed as cpm both per volume and per mg protein. There was a tendency for decreased activity with the decrease in sperm density of semen. The difference, however, lacked statistical significance. Enzyme activity in split semen was significantly lower in the first than in the second fraction.

Humans↗