Studies of the Interaction of Influenza Virus RNA Polymerase PAN with Endonuclease Inhibitors.

Influenza virus is a major causative agent of respiratory viral infections, and RNA polymerase catalyzes its replication and transcription activities in infected cell nuclei. Since it is highly conserved in all virus strains, RNA polymerase becomes a key target of anti-influenza virus agents. Although experimental studies have revealed the good inhibitory activity of endonuclease inhibitors to RNA polymerase, the mechanism is still unclear. In this study, the docking and molecular dynamics simulations have been performed to explore the interaction of three kinds of endonuclease inhibitors with the subunit (PAN) of RNA polymerase. Our calculations indicate that all these endonuclease inhibitors can bind to the binding pocket of PAN, in which the electronegative oxygen atoms of the inhibitors form a chelated structure with the two Mn2+ cations of the active center. The most important interaction between these inhibitors and PAN is electrostatic interaction. The electron density of the chelate oxygen atoms determines the magnitude of the electrostatic energy, and the chelated structure and orientation of inhibitors depend largely on the distance between the chelate oxygen atoms.

[Post-thaw sperm functions of high- and low-fertility sperm donors: a comparative study of 40 cases].

OBJECTIVE: To investigate sperm function indexes that can be used to effectively evaluate the sperm donors' fertility so as to select healthy post-thaw semen samples and improve the success rate of assisted reproductive technology. METHODS: According to the pregnancy outcomes, we divided 40 donor semen samples into a high-fertility group (n = 20) and a low-fertility group (n = 20). We measured and compared the concentration, progressive motility, morphology, acrosome intactness, DNA integrity and mitochondrial membrane potential (MMP) of the post-thaw sperm between the two groups. RESULTS: There were statistically significant differences between the high- and low-fertility groups in the percentages of morphologically normal sperm ([18.50 +/- 6.10]% vs [14.42 +/- 6.44]%, P < 0.01), acrosome intactness ([86.17 +/- 4.49]% vs [80.04 +/- 7.52]%, P < 0.05) and DNA fragmentation index ([9.21 +/- 3.22]% vs [15.72 +/- 8.20]%, P < 0.05), but not in MMP ([56.75 +/- 18.80]% vs [52.23 +/- 18.86]%, P > 0.05). A significantly positive correlation was found between MMP and sperm motility (r = 0.760, P < 0.05), but not between other sperm functions and sperm concentration and motility. CONCLUSION: Sperm concentration, motility, morphology, acrosome intactness rate and DNA integrity contribute effectively to the evaluation of the fertilization capacity of post-thaw donor semen samples.

[Pre-freezing equilibration improves post-thaw human semen parameters].

OBJECTIVE: To investigate the effect of pre-freezing equilibration on the cryo-survival of human sperm and to optimize the protocol of direct fumigation for the freeze-thawing of human sperm. METHODS: We collected 50 semen samples from healthy donors, each subjected to cryopreservation with 3 different methods: non-equilibration freezing (Group A), 10-min equilibration at room temperature before freezing (Group B), and 10-min equilibration at 4 degrees C before freezing (Group C). We examined all the post-thaw semen samples by computer-assisted semen analysis for the sperm motility parameters, and detected the sperm vitality and deformity index (SDI). RESULTS: The recovery rate of progressive sperm motility was (61.88 +/- 16.94)% in Group C, remarkably higher than in A ([48.61 +/- 16.44]%) and B ([49.41 +/- 13.77]%) (P < 0.05), but with no significant difference between the latter two. And there were no significant differences in sperm vitality and SDI among the three groups. CONCLUSION: Ten-minute equilibration at 4 degrees C before freezing can evidently improve the progressive motility of sperm in addition to its advantages of easy operation and controllable experimental condition.

Sperm donation and its application in China: a 7-year multicenter retrospective study.

Sperm donation in China is different from that in other countries due to cultural, social and political factors. This research presents the current status of sperm donation in Mainland China and highlights some problems. Between January 2003 and December 2009, 19 471 sperm donors were screened totally and 6467 donors (33.2%) were recruited. The primary reasons for non-recruitment were either inadequate semen parameters (55.0%) or positive results for sexually transmitted diseases (7.9%). There were 327 (1.7%) qualified donors who withdrew from the program because of frustration related to failed semen parameters, participation merely for free medical tests or job transfer. A questionnaire investigating donor intention, as well as other concerns associated with sperm donation, was distributed to 516 potential donors. All potential donors indicated their primary motivation as altruism, while 90.9% mentioned monetary reward as a second motivating factor. Approximately 93.4% of donors expressed some apprehension about the risk of consanguineous mating and the protection of their identity. Over the past 7 years, 488 389 vials of donors' semen have been cryopreserved. In 36 438 artificial insemination with donor sperm (AID) cycles, the clinical pregnancy rate was 23.9% and the live birth rate was 16.6%. In 7148 in vitro fertilization cycles, the clinical pregnancy rate was 45.8% and the live birth rate was 35.2%. Human sperm banks have been strictly monitored to ensure that each sperm donor can only impregnate five women nationwide. There is still a large gap between the supply and demand for sperm donation which may be solved by updated guidelines.

[Safety evaluation of the offspring conceived by assisted reproductive technology with donor's semen].

OBJECTIVE: To investigate and compare the incidences of birth defects in the offspring conceived by assisted reproductive technology (ART), including artificial insemination with the donor's semen (AID), in vitro fertilization with donor's semen (IVF-D) and intracytoplasmic sperm injection with the donor's semen (ICSI-D), and in those conceived through ART with the husband's semen, including AIH, IVF and ICSI, in order to further evaluate the safety of ART with the donor's semen. METHODS: From January 2005 to October 2009, Shanghai Human Sperm Bank provided sperm copies to 11 medical institutions, which resulted in a total of 904 offspring born by ART. We followed up all these cases and investigated the status of the offspring. The control group included 4195 offspring of infertile couples from 4 Reproductive Medical Centers approved by health management administrations, which were conceived by ART in the same period. After investigating the number of offspring and cases of birth defects caused by various methods of assisted reproductive technology, we compared the incidence of birth defects resulting from the donor's semen and that from the husband's. RESULTS: There were 7 cases of birth defects (0.77%) in the offspring born by ART with the donor's semen, and 42 cases (1.00%) in those born by ART with the husband's semen, with no significant differences between the two groups (P > 0.05). CONCLUSION: There were no significant differences in the category of birth defects between ART with the donor's semen and that with the husband's, while the incidence of birth defects resulting from ART with the donor's semen was significantly lower than that from ICSI in infertile couples. The present findings indicate a higher safety of ART with the donor's semen.

Vertical transmission of the Yq AZFc microdeletion from father to son over two or three generations in infertile Han Chinese families.

This study was carried out to analyze the vertical transmission of Yq AZFc microdeletions from father to son in infertile Han Chinese families to investigate genetic factors and family background affecting fertility status. The peripheral blood of infertile males in 19 Han families was extracted and screened with modified multiplex polymerase chain reaction (PCR). Family trees were drawn according to fertility status and clinical characteristics of the subjects. The vertical transmission of Yq AZFc microdeletions was detected in six cases of 19 investigated families (31.6%, 6/19). Although both fathers and sons showed a similar type of Yq AZFc deletion, the fathers were fertile, whereas the sons were infertile and showed severe oligozoospermia. The vertical transmission of Yq AZFc microdeletion from fertile fathers to infertile sons over generations is not rare. This has different effects on fertility status in fathers and sons in Han Chinese families. Both genetic factors and family background affect spermatogenetic phenotypes.

[Expression of OCTN2 mRNA in the human epididymis and its significance].

OBJECTIVE: To explore the mechanism of L-Carnitine transport and the expression of OCTN2 mRNA in the human epididymis so as to provide a theoretical basis for male contraception. METHODS: We collected specimens from human epididymides and determined the expressions of OCTN2 mRNA in the caput, corpus and cauda of the epididymis by RT-PCR. RESULTS: OCTN2 mRNA was expressed in the caput, corpus and cauda of the epididymis. CONCLUSION: The human epididymis may rely on OCTN2 for transporting L-Carnitine into the epididymal duct to promote sperm maturation. With the accumulation of information on OCTN2 in the human epididymis, OCTN2 will become a new molecular target for researches on male contraception.

[Study on the vertical transmission of Y chromosome microdeletions from father to son].

OBJECTIVE: To analyze the Y chromosome microdeletions in the family of the infertile male and to study on the vertical transmission of Y chromosome microdeletions from father to son. METHODS: The peripheral blood of infertile patients' family male members was extracted and analyzed with modified multiplex PCR. The infertile family tree was drawn according to the results. RESULTS: Two cases in twelve investigated families had azoospermia factor (AZFc) microdeletion heredity. The others had no heredity. CONCLUSION: AZFc microdeletion of the Y chromosome can be transmitted to the male offspring naturally,and the same deletion can result in different phenotypes in different individuals.

[Screening for Y chromosomal microdeletions in AZF region with modified multiplex PCR].

OBJECTIVE: Screening for Y chromosomal microdeletions in azoospermia factor (AZF) region with modified multiplex PCR. METHODS: 160 cases with spermatogenetic failure were recruited in the experimental group, while 90 cases of donors in controls. According to the laboratory guidelines supported by European Academy of Andrology (EAA) and European Molecular Genetics Quality Network (EMQN), Y chromosomal microdeletions in AZFa, b, c regions were screened with multiplex PCR. The primers of sequence targeted sites (STSs) and conditions of PCR were modified. RESULTS: Using modified multiplex PCR, 14 (8.75%) cases with Y chromosomal microdeletions were found in the experimental group, while no case in controls. There were 12 cases in AZFc, 1 case in AZFa + b + c, 1 case in AZFb + c. According to statistics, the difference between two groups was significant (P <0.001). Reaction products could be clearly separated with agarose gel and finished in 1 h. CONCLUSION: Modified multiplex PCR protocols supported by EAA and EMQN proved to be very accurate, sensitive and quick, which could be put into screening practice for Y chromosomal microdeletions in AZF region.

[A controlled randomized trial of the use of combined L-carnitine and acetyl-L-carnitine treatment in men with oligoasthenozoospermia].

OBJECTIVE: To determine the efficacy and safety of combined L-carnitine and acetyl-L-carnitine therapy in infertile males with oligoasthenozoospermia. METHODS: One hundred fifty patients with oligoasthenozoospermia were randomized selected into treatment and control groups. The treatment group with 90 patients were given L-carnitine (2 g/d) and acetyl-L-carnitine (1 g/d) orally, twice a day. The patients in control group were given Vitamin E 100 mg plus Vitamin C 100 mg, tid. The oral therapy lasted three months and patients accepted sperm analysis every one month. The L-carnitine level in seminal plasma was examined by high performance liquid chromatography (HPC). Side effects as well as pregnant rate were observed. RESULTS: In the treatment group, 85 patients out of 90 finished the three month treatment. Female spouses of 10 patients (11.6%) achieved pregnancy. Moreover, their forward motile sperm per ejaculation, total motile sperm, as well as the concentration of L-carnitine in seminal plasma were increased significantly (P < 0.01). In control group, 53 patients out of 60 completed three months therapy. Two pregnancy (3.7%) was observed. Though some increase was seen in number of forward motile sperm and total motile sperm per ejaculation, the changes were not statistically significant (P > 0.05). The difference of the pregnant rate between two groups was statistically significant. No side effects were found. CONCLUSION: Combined treatment with L-carnitine and acetyl-L-calmitine can be an effective and safe option for treating oligoasthenozoospermia by means of significantly improving forward motile sperm and total motile sperm per ejaculation, as well as increasing pregnant rates.