[Bacteriological analysis of semen samples from sperm donors].

OBJECTIVE: To explore the distribution and characteristics of semen bacteria in sperm donors. METHODS: For lack of the reference value for semen bacterial culture and colony count, we referred to the existing criteria for the diagnosis of male urinary tract infection (urine bacterial colonies >105 cfu/ml for infection, <104 cfu/ml for possible bacterial contamination, and 104－105 cfu/ml for suspected infection) and set the threshold value for unqualified semen culture at bacterial colonies ≥104cfu/ml. We performed bacterial culture of the semen samples from 3 160 sperm donors in the Chongqing Human Sperm Bank from April 2015 to November 2019, counted the bacterial colonies using the British Synbiosis automatic colony counter, and identified the bacterial species in the samples with bacterial colonies ≥104cfu/ml with the automatic microbial identification instrument. RESULTS: Of the 3 160 semen samples, 456 (14.43%) were found without bacterial growth, and the other 2 704 (85.57%) with bacterial growth, which included 143 (4.53%) with miscellaneous bacteria contamination and 2 561 (81.04%) positive for bacterial culture but not contaminated, the latter including 2 305 (72.94%) with bacterial colonies <104cfu/ml and 256 (8.10%) with bacterial colonies ≥104cfu/ml. Bacterial identification showed that 87.89% of the bacteria were Gram-positive (G+) and 12.11% Gram-negative (G－), mainly including Staphylococcus epidermidis (26.95%), Hemolytic staphylococcus (16.40%), Corynebacterium (13.28%), Enterococcus faecalis (6.64%) and Staphylococcus aureus (5.86%). CONCLUSIONS: Semen samples from sperm donors have a high rate of bacteria-carriers, and the bacteria vary widely in strain, with G+ bacteria as the main type.

[Characterization of the men undergoing autologous sperm preservation in Chongqing Human Sperm Bank].

OBJECTIVE: To analyze the characteristics of the males undergoing autologous sperm preservation (ASP), and provide some reference for human sperm banks to offer targeted service for those undergoing ASP. METHODS: We statistically analyzed the demographic features, reasons for ASP, and other relevant factors of the men applying for ASP in Chongqing from January 2016 to December 2019. RESULTS: Within 4 years, a total of 76 males applied for ASP, of whom about 63.2% came from Chongqing, 52.6% were aged 20－30 years old, 51.3% were undergraduates or above, 36.8% worked in government offices and public institutions, 61.9% were unmarried, nearly 80% acted by the doctor's advice, and 59.2% did it due to diseases, mainly including testis cancer, lymphoma and colon cancer, particularly before radio- or chemotherapy. Testicular sperm extraction (TESE) was successfully performed in 61 (80.3%) of the males. Of the 355 semen samples obtained, 83.1% were found with normal semen parameters, 60.5% cryopreserved successfully, and 4.3% of the frozen samples used for assisted reproduction. CONCLUSIONS: ASP is comparatively a novel practice, with only a few participants. Full use of the aggregation characteristics of the population undergoing ASP should be made, and targeted service provided for the key subjects identified so as to benefit more people in need.

[Bacterial culture of donor semen before and after cryopreservation: A preliminary study].

OBJECTIVE: To investigate the factors causing bacterial contamination of donor semen during cryopreservation. METHODS: Based on the WHO Laboratory Manual for the Examination and Processing of Human Semen (5th ed), we diluted donor semen samples with sperm cryopreservation medium in a 1∶1 (v/v) ratio. Before the experiment, we cultured bacteria in the sperm cup, sperm cryopreservation medium and Columbia blood a-gar medium to ensure sterile growth. We also conducted bacterial culture of 3,112 semen samples before and after freezing and, according to the number of bacterial colonies (NBC), divided them into a normal group (NBC before freezing <104 cfu/ml and >NBC after freezing) and an abnormal group (NBC before freezing ≥104 cfu/ml and ≥ NBC after freezing, or NBC before freezing < NBC after freezing), followed by bacterial species identification of the suspected colonies. RESULTS: Of the 3 112 donor semen samples, 2 458 (78.98%) were included in the normal, and the other 654 (21.02%) in the abnormal group (263 ï¼»8.45%ï¼½ with NBC before freezing ≥104 cfu/ml and ≥ NBC after freezing, and 391 ï¼»12.56%ï¼½ with NBC before freezing < NBC after freezing). In the suspected colonies, 217 (6.97%) strains of bacteria were isolated and identified, mainly including Staphylococcus epidermidis (23.96%), Staphylococcus haemolyticus (16.59%), Corynebacterium minutissimum (11.52%), Staphylococcus aureus (7.37%), and Enterococcus faecalis (5.99%). CONCLUSIONS: The bacteria detected in the donor semen mainly included Staphylococcus epidermidis, Staphylococcus haemolyticus, Corynebacterium minutissimum, Staphylococcus aureus and Enterococcus faecalis. Many factors may cause bacterial contamination of donor semen during cryopreservation, which can be reduced by employing sterile, clean and dry materials, appropriate semen preservation methods, normalized experimental environment, and standard operating procedures.

[Efficiency of sperm donation: An analysis of 440 qualified sperm donors in Chongqing Human Sperm Bank].

OBJECTIVE: To analyze the efficiency of sperm donation by qualified donors and provide some experience for improving the success rate of sperm donation in human sperm banks. METHODS: This study included 440 qualified sperm donors in Chongqing Human Sperm Bank from April 2015 to June 2019. We analyzed the general information about the donors, the causes of failed sperm donation and the results of semen bacterial culture. RESULTS: Among the 440 qualified donors, 11 (2.50%) did not donate sperm, 28 (6.36%) were excluded because of frequent failures to donate, 397 (90.2%) completed all the procedures of sperm donation, and 4 (0.91%) failed to undergo HIV test six months after the last donation. The 397 donors that fulfilled the procedures donated sperm for 2 965 person-times, of which 2 159 (72.8%) were qualified and 806 (27.2%) unqualified for substandard semen quality (n = 684 ï¼»23.1%ï¼½), semen volume <2 ml (n = 33 ï¼»1.11%ï¼½), abnormal seminal liquefaction (n = 14 ï¼»0.47%ï¼½), or positive semen bacterial culture (n = 75 ï¼»2.53%ï¼½). CONCLUSIONS: Substandard semen quality is the main factor affecting the efficiency of sperm donation. The staff of the human sperm bank should pay adequate attention to the first reception of and communication with the donors, dispel their worries, enhance health care guidance, prevent pollution and improve the success rate of sperm donation.

[An analysis of donor semen quality in Chongqing Human Sperm Bank].

OBJECTIVE: To evaluate the quality of the donor semen in Chongqing Human Sperm Bank and the influence of age on semen parameters. METHODS: We collected semen samples from 899 donors in Chongqing Human Sperm Bank and divided them into five groups according to the age of the semen donors: 22－25, 26－30, 31－35, 36－40, and >40 years old. Using the Makler Counting Chamber, we measured the semen volume, percentage of progressively motile sperm (PMS), total motile sperm, sperm concentration, total sperm count per ejaculate, and percentage of morphologically normal sperm (MNS). Then, we compared the semen parameters obtained with the fifth percentile and median reference values published in the WHO Laboratory Manual for the Examination and Processing of Human Semen-5th Ed (WHO 5th Ed) and among different age groups using the Kruskall-Wallis H test. RESULTS: The semen volume (1.8 ml), sperm concentration (25.0 × 106/ml), total sperm count (100.7 × 106/ejaculate) and MNS (4.3%) in the semen samples of the 899 donors were obviously higher than the fifth percentile values published in the WHO 5th Ed, and so were the first three parameters (4.0 ml, 88.0 × 106/ml, and 333.7 × 106/ejaculate) than the WHO median reference values. PMS (31.0%) and total motile (38.0%) were lower than the WHO fifth percentile values and so was MNS (11.6%) than the WHO median reference value. PMS (55.0%) and total motile sperm (61.0%), however, were coincident with the median reference values of WHO 5th Ed. Statistically significant differences were observed among the 22－25, 26－30, 31－35, 36－40 and >40 years old groups in perm concentration (88.0 ï¼»1.0－270.0ï¼½ vs 96.0 ï¼»5.0－335.0ï¼½ vs 100.0 ï¼»3.0－200.0ï¼½ vs 105 ï¼»15.0－225.0ï¼½ vs 90.0 ï¼»22.0－159.0ï¼½ × 106/ml, P < 0.05), but not in the semen volume, PMS, total sperm motility, total sperm count or MNS (P > 0.05). CONCLUSIONS: The donor semen in Chongqing Human Sperm Bank is generally of high quality. Sperm concentration significantly increases with age but decreases in men aged >40 years.

[Bacterial culture of donor semen: Analysis of results].

OBJECTIVE: To investigate bacterial infection and the distribution of different bacterial species in the donor semen and the influence of different bacterial counts on semen quality. METHODS: Bacterial colonies in the semen samples from 1 126 donors were counted with the Synbiosis Protocol 3 Automatic Colony Counter and the bacterial species with a colony count ≥104 cfu/ml identified with the VITEK2 Compact Automatic Biochemical Analyzer. The Makler Sperm Counting Board was used to examine the semen quality of the semen samples with a colony count = 0 cfu/ml (n = 22, group A), those with a colony count <104 cfu/ml (n = 22, group B) and those with a colony count ≥104 cfu/ml (n = 22, group C). Univariate analysis was employed for comparison of semen quality among different groups. RESULTS: Among the 1 126 donor semen samples cultured, 5 (0.44%) showed mixed bacterial contamination and 993 (88.58%) showed none but with growth of a certain species of bacteria, 2.22% (22/993) with a colony count ≥104 cfu/ml, mainly including Streptococcus bovis, tiny bacilli, Staphylococcus epidermis, and Staphylococcus aureus, among which gram-positive and gram-negative bacteria accounted for 95.45% (21/22) and 4.54% (1/22), respectively. Compared with group A, groups B and C manifested significantly reduced total sperm count (ï¼»567.5 ± 327.6ï¼½ vs ï¼»421.9 ± 155.9ï¼½ and ï¼»389.9 ± 110.6ï¼½ × 106 per ejaculate, P <0.05) and percentage of progressively motile sperm (ï¼»65.0 ± 6.5ï¼½ vs ï¼»61.0 ± 3.5ï¼½ and ï¼»61.6 ± 4.3ï¼½ %, P <0.05). There were no statistically significant differences among the three groups in the semen liquefaction time, semen pH value, total sperm motility or percentage of morphologically normal sperm (P > 0.05). Of the 284 randomly selected semen samples, 34 (11.97%) were found positive for Ureaplasma urealyticum (UU) and no significant difference was observed in the semen quality between the UU-positive and UU-negative samples (P> 0.05). CONCLUSIONS: The bacteria-positive rate is high in the donor semen and the bacterial species are varied, mainly including gram-positive bacteria. Semen quality is reduced with the increased number of bacterial colonies.

The dynamics of polycomb group proteins in early embryonic nervous system in mouse and human.

Polycomb group (PcG) proteins are transcription regulatory proteins that control the expression of a variety of genes and the antero-posterior neural patterning from early embryogenesis. Although expression of PcG genes in the nervous system has been noticed, but the expression pattern of PcG proteins in early embryonic nervous system is still unclear. In this study, we analyzed the expression pattern of PRC1 complex members (BMI-1 and RING1B) and PRC2 complex members (EED, SUZ12 and EZH2) in early embryonic nervous system in mouse and human by Western blot and Immunohistochemistry. The results of Western blot showed that EED protein was significantly up-regulated with the increase of the day of pregnancy during the early embryogenesis in mouse. BMI-1 protein level was significantly increased from the day 10 of pregnancy, when compared with the day 9 of pregnancy. But the SUZ12, EZH2 and RING1B protein level did not change significantly. From the results of Immunohistochemistry, we found that the four PcG proteins were all expressed in the fetal brain and fetal spinal cord in mouse. In human, the expression of EED, SUZ12, and EZH2 was not significantly different in cerebral cortex and sacral spinal cord, but BMI-1 and RING1B expression was enhanced with the development of embryos in early pregnancy. Collectively, our findings showed that PRC1 and PRC2 were spatiotemporally expressed in brain and spinal cord of early embryos.

[Birth defects among children aged 0-4 in Chongqing in 2010].

OBJECTIVE: To learn the prevalence of birth defects in Chongqing. METHODS: A total of 6579 children aged 0 - 4 were chosen by multistage cluster sampling method in central economic districts of Chongqing. A total of 32 kinds of birth defects were selected. All the birth defects, except for the visible congenital malformation, must be diagnosed by the hospital in county. And municipal experts would make a consultation for those that couldn't be diagnosed at the level of county. Investigators trained strictly made a body examination and inquired medical history from May to September in 2010. RESULTS: A total of 6541 subjects, aged from 0 to 4, were recruited in the present study, and 216 of them were born with birth defects. The total prevalence was 33.48‰ (95%CI: 29.09‰-37.87‰). There were 25 kinds of birth defects in total, the first five were hernia (20.15‰), congenital heart disease (2.17‰), polydactylism (2.02‰), cryptorchid (1.86‰) and funnel chest (1.86‰). The prevalence among boys was 52.99‰ (178/3359), higher than girls 12.29‰ (38/3092) (χ2=82.42, P<0.05). The prevalence in each group aged 0, 1, 2, 3, 4 were 39.30‰ (36/916), 38.79‰ (41/1057), 36.46‰ (56/1536), 28.38‰ (47/1656), 27.99‰ (36/1286), respectively. There were no statistical differences in each group (χ2=4.83, P=0.31). The prevalence in countryside was 40.17‰ (136/3386), higher than that in town 26.18‰ (80/3065) (χ2=9.83, P<0.05). CONCLUSION: The rate of birth defects in Chongqing was moderate, and boys and kids in rural areas had a higher prevalence rate than their counterparts.

[An analysis on chromosome X, Y and 18 in the spermatozoa of asthenospermia patients by triple-color fluorescence in situ hybridization].

OBJECTIVE: To analyze the numerical aberration of chromosome X, Y and 18 in the spermatozoa of asthenospermia patients by triple-color fluorescence in situ hybridization. METHODS: The experiment included 10 asthenospermia patients and 5 healthy men with normal semen quality as controls. Fluorescence in situ hybridization (FISH) and probes for chromosomes including X, Y and 18 were used to determine the frequency of the aneuploid of the chromosomes in spermatozoa. RESULTS: Of the 45,547 spermatozoa counted from the semen samples, the hybridization rate was 99.18%. The frequencies of the chromosome disomies including XX18, XY18, YY18, X1818 and Y1818 were (0.124 +/- -0.086)%, (0.360 +/- 0.380)%, (0.109 +/- 0.195)%, (0.342 +/- 0.746)% and (0.299 +/- 0.564)% in the case group and (0.014 +/- 0.019)%, (0.090 +/- 0.080)%, (0.030 +/- 0.031)%, (0.068 +/- 0.103)% and (0.075 +/- 0.083)% in the control. The sperm aneuploid rate was 9.25% in the former and 2.70% in the latter, with significant difference in between (P< 0.01). CONCLUSION: Asthenospermia patients have a higher aneuploid rate of sperm chromosome than normal fertile men. However, larger samples are yet to be studied to obtain more scientific evidence.