Characterization and application of several lysis cassettes / 生物工程学报

Lysis is a common functional module in synthetic biology and is widely used in genetic circuit design. Lysis could be achieved by inducing expression of lysis cassettes originated from phages. However, detailed characterization of lysis cassettes hasn't been reported yet. Here, we first adopted arabinose- and rhamnose-inducible systems to develop inducible expression of five lysis cassettes (S105, A52G, C51S S76C, LKD, LUZ) in Escherichia coli Top10. By measuring OD600, we characterized the lysis behavior of strains harboring different lysis cassettes. These strains were harvested at different growth stages, induced with different concentrations of chemical inducers, or contained plasmids with different copy numbers. We found that although all five lysis cassettes could induce bacterial lysis in Top10, lysis behaviors differed a lot at various conditions. We further found that due to the difference in background expression levels between strain Top10 and Pseudomonas aeruginosa PAO1, it was hard to construct inducible lysis systems in strain PAO1. The lysis cassette controlled by rhamnose-inducible system was finally inserted into the chromosome of strain PAO1 to construct lysis strains after careful screen. The results indicated that LUZ and LKD were more effective in strain PAO1 than S105, A52G and C51S S76C. At last, we constructed an engineered bacteria Q16 using an optogenetic module BphS and the lysis cassette LUZ. The engineered strain was capable of adhering to target surface and achieving light-induced lysis by tuning the strength of ribosome binding sites (RBSs), showing great potential in surface modification.

Development and application of a rapid gene manipulating toolbox for Pseudomonas aeruginosa / 生物工程学报

Manipulation of genes, including knock-out or knock-in, replacement of gene elements (such as promoters), fusion with a fluorescent protein gene, and construction of in situ gene reporter, is required in most of the biotechnological laboratories. The widely used gene manipulating methods based on two-step allelic exchange are cumbersome in terms of constructing plasmids, transforming and screening. In addition, the efficiency of using this method for long fragment knockout is low. To simplify the process of gene manipulation, we constructed a minimized integrative vector pln2. When a gene needs to be inactivated, an internal fragment of the target gene (non-frameshift) is cloned into the pln2 plasmid. Once the single-crossover recombination between genome and the constructed plasmid occurs, the endogenous gene is segmented by the plasmid backbone and thus inactivated. We developed a toolbox based on pln2 that can be used for different genomic operation mentioned above. With the help of this toolbox, we successfully knocked out large fragments of 20-270 kb.

Functional synergism of pyoverdine and the S-type pyocins of Pseudomonas aeruginosa / 生物工程学报

Pyocin S2 and S4 in Pseudomonas aeruginosa use the same uptake channels as the pyoverdine does in bacteria, indicating a possible connection between them. In this study, we characterized the single bacterial gene expression distribution of three S-type pyocins (Pys2, PA3866, and PyoS5) and examined the impact of pyocin S2 on bacterial uptake of pyoverdine. The findings demonstrated that the expression of the S-type pyocin genes was highly differentiated in bacterial population under DNAdamage stress. Moreover, exogenous addition of pyocin S2 reduces the bacterial uptake of pyoverdine so that the presence of pyocin S2 prevents the uptake of environmental pyoverdine by non-pyoverdine synthesizing 'cheaters', thereby reducing their resistance to oxidative stress. Furthermore, we discovered that overexpression of the SOS response regulator PrtN in bacteria significantly decreased the expression of genes involved in the synthesis of pyoverdine, significantly decreasing the overall synthesis and exocytosis of pyoverdine. These findings imply a connection between the function of the iron absorption system and the SOS stress response mechanism in bacteria.

Design, synthesis, and neuroprotective and anti-platelet aggregation research of 3-n-butylphthalide derivatives / 药学学报

Butylphthalide and ferulic acid exhibit excellent therapeutic effects in ischemic stroke. In this research, twelve 3-n-butylphthalide derivatives were designed by molecular hybridization strategy. The target compounds were obtained by nucleophilic substitution, reduction reaction, esterification reaction and elimination reaction, and the structure was confirmed by 1H NMR, 13C NMR and ESI-MS. All compounds were evaluated for neuroprotective activity against OGD/R-induced neurotoxicity in rat cortical neurons by MTT assay. The compounds with the best neuroprotective activity were biologically evaluated for their ability to inhibit platelet aggregation induced by arachidonic acid (AA) and adenosine diphosphate (ADP) via the Bron method．The results indicate that 7b exhibited potent neurocyte protective activity as well as prominent anti-platelet aggregation activity. Compound 7b has potential to be developed as a drug for ischemic stroke.

Genetic diagnosis of a fetus with Dandy-Walker syndrome / 中华医学遗传学杂志

Objective@#To explore the genetic basis for a fetus with Dandy-Walker malformation.@*Methods@#G-banding chromosomal karotyping, single nucleotide polymorphism microarray (SNP array) and fluorescence in situ hybridization (FISH) were carried out for the fetus. Chromosomal karyotyping and FISH assay were also carried out for both parents.@*Results@#SNP array has detected a 4266 kb microdeletion at 6p25.3p25.1 in the fetus, which was confirmed by FISH. FISH analysis of the parents demonstrated that the father has carried a cryptic t(6; 14)(p25.1; p13) translocation, while the fetus has a der(6)t(6; 14)(p25.1; p13) derived the paternal translocation.@*Conclusion@#The der(6)t(6; 14)(p25.1; p13) probably underlies the Dandy-Walker malformation in the fetus. The 6p25.3p25.1 microdeletion is due to unbalanced gametes produced by the father’s cryptic balanced translocation.

Genetic diagnosis of a fetus with Dandy-Walker syndrome / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis for a fetus with Dandy-Walker malformation.@*METHODS@#G-banding chromosomal karotyping, single nucleotide polymorphism microarray (SNP array) and fluorescence in situ hybridization (FISH) were carried out for the fetus. Chromosomal karyotyping and FISH assay were also carried out for both parents.@*RESULTS@#SNP array has detected a 4266 kb microdeletion at 6p25.3p25.1 in the fetus, which was confirmed by FISH. FISH analysis of the parents demonstrated that the father has carried a cryptic t(6;14) (p25.1;p13) translocation, while the fetus has a der(6)t(6;14)(p25.1;p13) derived the paternal translocation.@*CONCLUSION@#The der(6)t(6;14)(p25.1;p13) probably underlies the Dandy-Walker malformation in the fetus. The 6p25.3p25.1 microdeletion is due to unbalanced gametes produced by the father's cryptic balanced translocation.

Genetic analysis of a child with Sotos syndrome / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis for a child with mentally retardation.@*METHODS@#G-banding karyotyping, single nucleotide polymorphism array (SNP-array) and fluorescence in situ hybridization (FISH) were performed for the child. Karyotyping and FISH were also carried out for her parents.@*RESULTS@#SNP-array has detected a 5077 kb microdeletion at 5q35.2q35.3 and a 4964 kb microduplication at 7q36.2q36.3 in the child. The results were confirmed by FISH. Based on above results, the father was subsequently found to carry a cryptic t(5;7) (q35.2; q36.2) translocation. The child was verified to have inherited a der(5) t(5;7)(q35.2; q36.2) from her father.@*CONCLUSION@#The 5077 kb microdeletion at 5q35.2q35.3 may have predisposed to the Sotos syndrome in the child. SNP-array combined with G-banding karyotyping and FISH can help to detect cryptic chromosomal translocations among patients.

Genetic analysis of a fetus with multiple malformations caused by complex translocations of four chromosomes / 浙江大学学报·医学版

OBJECTIVE@#To conduct genetic analysis in a fetus with complex translocation of four chromosomes.@*METHODS@#G-banded chromosome karyotype analysis, single nucleotide polymorphism array (SNP array) and fluorescence hybridization (FISH) were performed in a fetus with multiple malformations. Peripheral blood chromosome karyotype and FISH were also carried out for the parents.@*RESULTS@#The fetal amniotic fluid karyotype was 46, XY, t(12; 13)(q22; q32). SNP array analysis showed that there were 20 192 kb duplication at 1q42.13q44 and 13 293 kb deletion at 15q26.1q26.3 in the fetus. The results of karyotype and SNP array were inconsistent. FISH analyses on the parental peripheral blood samples demonstrated that the mother was a cryptic 46, XX, t(1; 15)(q42.1; q26.1) translocation. The fetus had inherited 46, XY, t(12; 13)(q22; q32) from his father and der(15)t(1; 15)(q42.1; q26.1) from his mother.@*CONCLUSIONS@#The 1q42.13q44 duplication and 15q26.1q26.3 deletion may have contributed to the abnormal sonographic features of the fetus. The combination of cytogenetic, SNP array and FISH techniques was beneficial for providing an accurate genetic counseling.

Expression profiles of microRNA in peripheral blood mononuclear cells and immune factors in pregnant women with hepatitis B virus infection / 中华医学遗传学杂志

OBJECTIVE@#To determine the expression profile of microRNA (miRNA) in peripheral blood mononuclear cells (PBMC) and immune factors in pregnant women with hepatitis B virus (HBV) infection.@*METHODS@#A total of 182 pregnant women infected with HBV were randomly selected, with 40 healthy pregnant women and 35 non-pregnant women as controls. High-throughput sequencing was used to detect RNA in the PBMC of all subjects. Indirect ELISA method was used to determine the changes of cytokines in peripheral blood samples.@*RESULTS@#Compared with the control group, 18 differentially expressed miRNA were identified in those with HBV infection (P< 0.01). Among these, miR-3607-3p, miR-20a, miR-1296, miR-153-1 and miR-X4 may directly regulate the transcriptional level of target genes including IL-10, IL-18, IL-16, MCP-1, NUP50 and CCR1. Meanwhile, peripheral blood cytokines IL-10, IL-18, IL-16 and MCP-1 were significantly increased in those with HBV infection (P<0.01), with the expression level of IL-16 and MCP-1 being strongly correlated with the viral load.@*CONCLUSION@#The expression profiles of miRNA in PBMC and cytokines in peripheral blood can change significantly during pregnancy, both may be involved in the immune response to HBV infection.

Prenatal diagnosis of a fetus with Phelan-McDermid syndrome / 中华医学遗传学杂志

OBJECTIVE@#To diagnose a fetus with Phelan-McDermid syndrome (PMS) using various techniques.@*METHODS@#Single nucleotide polymorphism array (SNP Array), multiplex ligation-dependent probe amplification (MLPA), fluorescence in situ hybridization (FISH) were applied in conjunction for the prenatal diagnosis of the fetus.@*RESULTS@#SNP Array detected a 4.03 Mb microdeletion at 22q13.31q13.33 in the fetus, which was confirmed by FISH and MLPA. FISH analysis of the parents suggested that the 22q13.31q13.33 deletion has a de novo origin.@*CONCLUSION@#Combined use of various techniques can enable accurate prenatal diagnosis and genetic counseling.

Value of combined detection of claudin 4 and high-risk human papilloma virus in high-grade squamous intraepithelial lesion and cervix squamous cell carcinoma / 浙江大学学报·医学版

OBJECTIVE@#To investigate the expression of claudin 4 (CLDN4) in cervical tissues from patients with different cervical lesions, and to explore the value of combined detection of CLDN4 and high risk human papilloma virus (HR-HPV).@*METHODS@#The cervical tissue specimens of low-grade squamous intraepithelial lesion (LSIL, =30), high-grade squamous intraepithelial lesion (HSIL, =30), squamous cell carcinoma (SCC, =30) as well as chronic cervicitis (control, =30) were collected from the Sir Run Run Shaw Hospital of Zhejiang University during June 2015 and December 2016. The expression of CLDN4 protein in tissue specimens was detected by immunohistochemistry, HR-HPV was detected by real-time quantitative PCR, and the cervical exfoliated cells were examined by thinprep cytologic test (TCT). The ROC curve was applied to analyze the diagnostic value of TCT combined with HR-HPV and CLDN4 combined with HR-HPV tests for HSIL and SCC of the cervix.@*RESULTS@#With the increase of the severity of cervical lesions, the positive rate of CLDN4 expression rose (=0.832, <0.05). Positivity of both HR-HPV infection and CLDN4 expression was found mainly in the HSIL and SCC groups. The areas under curve (AUC) of TCT combined with HR-HPV and CLDN4 combined with HR-HPV tests for diagnosis of HSIL and SCC were 0.683 and 0.633, respectively; the sensitivity, specificity, positive predictive value, negative predictive value and accuracy of TCT combined with HR-HPV test for diagnosis of HSIL and SCC were 100.0%, 36.7%, 61.2%, 100.0% and 46.7% respectively; those of CLDN4 combined with HR-HPV test were 96.7%, 30.0%, 58.0%, 90.0% and 55.0%, respectively.@*CONCLUSIONS@#CLDN4 expression may be related to the occurrence and development of cervical carcinoma and precancerous lesions. CLDN4 combined with HR-HPV test may be used for diagnosis of HSIL and SCC of the cervix clinically.

Advances on prenatal diagnosis of birth defects associated with genetic disorders / 浙江大学学报·医学版

Birth defects have become a major public health concern in the world, which can be resulted from the harmful environmental factors, genetic mutations or their co-effects. Prenatal diagnosis or preimplantation diagnosis has been considered as the only effective way for the prevention of the birth of those defects. Besides karyotype analysis and fluorescencehybridization, chromosomal microarray analysis and next generation sequencing or its derivatives are in common use. This article reviews the advances of the newly emerging molecular techniques in prenatal diagnosis of birth defects associated with genetic disorders.

Single nucleotide polymorphism-array in genetic analysis of chorionic villi from early spontaneous miscarriages / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To assess the clinical application of single nucleotide polymorphism (SNP)-array in detecting abnormal chromosome karyotypes of chorionic villi from early spontaneous abortuses.</p><p><b>METHODS</b>A total of 861 chorionic villus samples from unexplained early spontaneous abortion were collected from Women's Hospital, Zhejiang University School of Medicine during October 2013 and June 2016, and SNP-array was performed to detect genome-wide DNA copy number variants.</p><p><b>RESULTS</b>All samples were successfully tested by SNP-array and 440 cases (51.10%) were found to have abnormal chromosome constitutions. Aneuploidy was identified in 358 (41.58%) cases, distributing in all chromosomes except chromosome 1. Triploidy and haploidy were found in 21 (2.44%) and one case (0.12%), respectively. Thirty-seven cases (4.30%) were identified as single chromosomal segment deletion or duplication, 25 of which were less than 10 Mb in size. For 6 of 25 cases with unclear pathogenesis, family studies were carried out to identify origin of deletion or duplication, showing that 4 cases were de novo and 2 were inherited from one of the parents. Twenty-three cases (2.67%) showed two chromosomal deletion/duplication segments. Combining with karyotyping and fluorescencehybridization, 6 cases were identified as de novo aberration and 11 carried small-size segmental balanced abnormality.</p><p><b>CONCLUSIONS</b>SNP-array can provide a relatively comprehensive genetic analysis of chorionic villi and can detect various kinds of chromosome abnormalities in spontaneous miscarriages.</p>

Research progress on the safety of offsprings conceived by assisted reproductive technology / 浙江大学学报·医学版

Assisted reproductive technology (ART) employs superovulation,culture and other micromanipulation to complete oocyte maturation, fertilization and early embryo development. Although these techniques have been successfully applied to solve infertility problems, the process may interfere in cell proliferation, differentiation and growth. The clinical and laboratory studies on the safety issue of ART are reviewed in this article. Studies found that the incidence of birth defects increased in ART offspring. Superovulation,culture and intracytoplasmic sperm injection may induce epigenetic aberrations during embryo development, which would influence the development of ART conceived children. The epigenetic susceptibility related to ART might be transmitted to subsequent generations, and the potential impact on ART offspring still need further investigation. In addition, ART treatments may also increase the risk of genetic diseases.

Single-cell analysis method for twitching motility of Pseudomonas aeruginosa / 生物工程学报

Twitching motility is very important for Pseudomonas aeruginosa in the adaptation of surface environment and in the 3-D structure formation of mature biofilm. To quantitatively characterize twitching motility in situ, we developed a method by combining high-throughput data acquisition, automatic image processing and database establishment. This method is based on single cell analysis and big data visualization. A periodic relaxation of 0.9 second was resolved during slingshot motility analysis. Twitching motilities of bacteria under addition of two quorum sensing signaling molecules were studied, cells moved faster after signal addition. This method may help understand the molecular mechanism and regulatory circuits of twitching motility.

Applications of zebrafish xenotransplantation models for in vivo evaluation of anticancer drug sensitivity test / 中国比较医学杂志

Objective To evaluate the sensitivity to 5 clinically commonly used anticancer drugs in vivo using the zebrafish xenotransplantation models of human lung cancer,stomach cancer,and liver cancer cells,respectively. Methods Zebrafish xenotransplantation models of A549 lung cancer cells,SGC-7901 stomach cancer cells and HepG2 liver cancer cells were established. The xenograft models of A549 cells were treated with three different doses of cis-platinum, paclitaxel, vinorelbine, endostar and bevacizumab, respectively. The SGC-7901 model was treated with three concentrations or doses of paclitaxel, irinotecan, hydroxyurea, cis-platinum and 5-fluorouracil, respectively. And the HepG2 model was treated with three concentrations or doses of adriamycin,gemcitabine,hydroxyurea,cis-platinum and 5-fluorouracil. The tumors were analyzed and quantified in vivo by fluorescence microscopy,and the inhibition rates of tumor growth with each drug were calculated and compared with the model control group for statistical significance. Results All of the tested anticancer drugs showed inhibitory effect on tumor cells in the zebrafish xenograft models with statistical significance in a dose-dependent manner. During the drug sensitivity test,the inhibition rate of bevacizumab on A549 lung cancer cells decreased in the order(65%)> cis-platinum(55%)> vinorelbine(40%)> endostar(39%)>paclitaxel(27%). As for the SGC-7901 stomach cancer cells, the tumor growth inhibition rate decreased in the order hydroxyurea(46%)> 5-FU(31%)= irinotecan(31%)> paclitaxel(26%)> cis-platinum(24%). And the therapeutic effect of cis-platinum on the HepG2 liver cancer cells decreased in the order(64%)> hydroxyurea(56%)>gemcitabine(46%)> adriamycin(45%)> 5-FU(38%). Conclusions Zebrafish xenotransplantation models of cancer cells are suitable for in vivo sensitivity test of anticancer drugs.

Influence of the DNA integrity of optimized sperm on the embryonic development and clinical outcomes of in vitro fertilization and embryo transfer / 中华男科学杂志

<p><b>OBJECTIVE</b>To investigate the influence of the DNA integrity of optimized sperm on the embryonic development and clinical outcomes of in vitro fertilization and embryo transfer (IVF-ET).</p><p><b>METHODS</b>This study included 605 cycles of conventional IVF-ET for pure oviductal infertility performed from January 1, 2013 to December 31, 2014. On the day of retrieval, we examined the DNA integrity of the sperm using the sperm chromatin dispersion method. According to the ROC curve and Youden index, we grouped the cycles based on the sperm DNA fragmentation index (DFI) threshold value for predicting implantation failure, early miscarriage, and fertilization failure, followed by analysis of the correlation between DFI and the outcomes of IVF-ET.</p><p><b>RESULTS</b>According to the DFI threshold values obtained, the 605 cycles fell into four groups (DFI value < 5%, 5-10%, 10-15%, and ≥ 15%). Statistically significant differences were observed among the four groups in the rates of fertilization, cleavage, high-quality embryo, implantation, clinical pregnancy, early miscarriage, and live birth (P < 0.05), but not in the rates of multiple pregnancy, premature birth, and low birth weight (P > 0.05). DFI was found to be correlated negatively with the rates of fertilization (r = -0.32, P < 0.01), cleavage (r = -0.19, P < 0.01), high-quality embryo (r = -0.40, P < 0.01), clinical pregnancy (r = -0.20, P < 0.01), and live birth (r = -0.09 P = 0.04), positively with the rate of early miscarriage (r = 0.23, P < 0.01), but not with the rates of multiple pregnancy (r = -0.01, P = 0.83), premature birth (r = 0.04, P = 0.54), and low birth weight (r = 0.03, P = 0.62).</p><p><b>CONCLUSION</b>The DNA integrity of optimized sperm influences fertilization, embryonic development, early miscarriage, and live birth of IVF-ET, but its correlation with premature birth and low birth weight has to be further studied.</p>

Values of the sperm deformity index, acrosome abnormity rate, and sperm DNA fragmentation index of optimized sperm in predicting IVF fertilization failure / 中华男科学杂志

<p><b>OBJECTIVE</b>To investigate the values of the sperm deformity index (SDI), acrosome abnormity rate (AAR), and DNA fragmentation index (DFI) of optimized sperm in the prediction of fertilization failure (fertilization rate < 25%) in conventional in vitro fertilization (IVF).</p><p><b>METHODS</b>We selected 695 cycles of conventional IVF for pure oviductal infertility in this study, including 603 cycles of normal fertilization and 92 cycles of fertilization failure. On the day of oocyte retrieval, we examined sperm morphology, acrosome morphology, and DNA fragmentation using the Diff-Quik, PSA-FITC and SCD methods. We established the joint predictor (JP) by logistic equation and analyzed the values of different parameters in predicting fertilization failure with the receiver operating characteristic (ROC) curve.</p><p><b>RESULTS</b>The fertilization rate was negatively correlated with SDI (r = - 0.07; P = 0.03), AAR (r = -0.49; P < 0.01), and DFI (r = -0. 21; P < 0.01). The SDI, AAR, and DFI in the normal fertilization group were 1.24 ± 0.20, (7.75 ± 2.28)%, and (7.87 ± 3.15)%, and those in the fertilization failure group were 1.42 ± 0.15, (12.02 ± 3.06)%, and (13.32 ± 4.13)%, respectively, all with statistically significant differences between the two groups (P < 0.05). SDI, AAR, and DFI were all risk factors of fertilization failure ( OR = 2.68, 14.11, and 3.85; P = 0.01, < 0.01, and < 0.01). The areas under the ROC curves for SDI, AAR, DFI, and JP were 0.651 ± 0.033, 0.895 ± 0.019, 0.789 ± 0.022, and 0.915 ± 0.017, respectively. According to the Youden index, the optimal cut-off values of SDI, AAR, and DFI obtained for the prediction of fertilization failure were approximately 1.45, 10%, and 12%.</p><p><b>CONCLUSION</b>The SDI, AAR and DFI of optimized sperm are closely associated with the fertilization rate, and all have the value for predicting fertilization failure in IVF. The AAR is more valuable than the other single predictors, but JP is more effective than the AAR.</p>

Correlation of the DNA fragmentation index and malformation rate of optimized sperm with embryonic development and early spontaneous abortion in IVF-ET / 中华男科学杂志

<p><b>Objective</b>To investigate the effects of the DNA fragmentation index (DFI) and malformation rate (SMR) of optimized sperm on embryonic development and early spontaneous abortion in conventional in vitro fertilization and embryo transfer (IVF-ET).</p><p><b>METHODS</b>We selected 602 cycles of conventional IVF-ET for pure oviductal infertility that had achieved clinical pregnancies, including 505 cycles with ongoing pregnancy and 97 cycles with early spontaneous abortion. On the day of ovum retrieval, we examined the DNA integrity and morphology of the rest of the optimized sperm using the SCD and Diff-Quik methods, established the joint predictor (JP) by logistic equation, and assessed the value of DFI and SMR in predicting early spontaneous abortion using the ROC curve.</p><p><b>RESULTS</b>The DFI, SMR, and high-quality embryo rate were (15.91±3.69)%, (82.85±10.24)%, and 46.53% (342/735) in the early spontaneous abortion group and (9.30±4.22)%, (77.32±9.19)%, and 56.43% (2263/4010) respectively in the ongoing pregnancy group, all with statistically significant differences between the two groups (P<0.05 ). Both the DFI and SMR were the risk factors of early spontaneous abortion (OR = 5.96 and 1.66; both P< 0.01). The areas under the ROC curve for DFI, SMR and JP were 0.893±0.019, 0.685±0.028, and 0.898±0.018, respectively. According to the Youden index, the optimal cut-off values of the DFI and SMR obtained for the prediction of early spontaneous abortion were approximately 15% and 80%. The DFI was correlated positively with SMR (r= 0.31, P<0.01) but the high-quality embryo rate negatively with both the DFI (r= －0.45, P<0.01) and SMR (r= －0.22, P<0.01).</p><p><b>CONCLUSIONS</b>The DFI and SMR of optimized sperm are closely associated with embryonic development in IVF. The DFI has a certain value for predicting early spontaneous abortion with a threshold of approximately 15%, but SMR may have a lower predictive value.</p>

Microsurgical treatment of obstructive azoospermia: a report of 76 cases / 中华男科学杂志

<p><b>OBJECTIVE</b>To investigate the clinical effect of microsurgical vasoepididymostomy and/or vasovasostomy in the treatment of obstructive azoospermia.</p><p><b>METHODS</b>This study included 76 patients with obstructive azoospermia, 53 treated by bilateral vasoepididymostomy (8 involving the epididymal head, 18 involving the epididymal body, 5 involving the epididymal tail, and 22 involving the epididymal head, body and tail), 14 by unilateral vasoepididymostomy, and the other 9 by unilateral vasoepididymostomy + unilateral vasovasostomy (including cross anastomosis). We followed up the patients for 2 to 16 months for the patency rate, routine semen parameters, and pregnancy outcomes.</p><p><b>RESULTS</b>The success rate of bilateral vasoepididymostomy, unilateral vasoepididymostomy, and unilateral vasoepididymostomy + unilateral vasovasostomy (including cross anastomosis) were 62.26% (33/53), 35.71% (5/14), and 77.78% (7/9), respectively. The average sperm concentrations in the three groups of patients were (27.9 +/- 5.74), (11.8 +/- 8.33), and (19.9 +/- 7.53) x 10(6)/ml, the average total sperm counts were (65.6 +/- 13.71), (28.0 +/- 15.86), and (69.2 +/- 28.59) x 10(6), and the mean rates of progressively motile sperm were (22.3 +/- 3.18), (11.0 +/- 9.77), and (15.8 +/- 5.05)%, respectively. The success rates of bilateral vasoepididymostomy that involved the epididymal head, body, tail, and all the three parts were 62.5, 72.22, 60, and 54.55%, respectively. Natural pregnancy was achieved in 8 (10.53%) of the total number of cases.</p><p><b>CONCLUSION</b>Microsurgery is effective for the treatment obstructive azoospermia. Unilateral vasoepididymostomy + unilateral vasovasostomy is superior to the other procedures, followed by bilateral vasoepididymostomy. Bilateral vasoepididymostomy involving the epididymal body may achieve a slightly better effect than that involving the other epididymal parts.</p>