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Biomedical subjects

Li Lin

Publications and source records attributed to Li Lin.

At least 37 records · Page 2Linked to original sources
PubMed2006

Arrhythmogenic action of endothelin-1(1-31) through conversion to endothelin-1(1-21).

Endothelin (ET)-1(1-21) is known to play an important role in the pathogenesis of acute ischemic arrhythmia. In the present study, we attempted to determine whether administration of ET-1(1-31) would result in arrhythmia in perfused isolated rat hearts. Forty-eight Sprague-Dawley rats weighing approximately 250-350 g were randomized into 6 groups. Heart was isolated and perfused in a Langendorff mode. The effects of ET-1(1-31) on arrhythmia, heart rate, coronary flow, and heart function were analyzed. Perfusion with 1 nM ET-1(1-31) resulted in frequent ventricular ectopic beats (VEBs) and ventricular tachycardia (VT). Overall VEB was 128.0 (approximately 66.0-1015.0), and the arrhythmia score (AS) was 2.18 +/- 0.87; both were significantly higher than those of the control group (P < 0.01). Pretreatment with perfusion of 10 nM of the ETA-receptor antagonist BQ(123) markedly attenuated the occurrence of VEB and VT induced by ET-1(1-31). AS in 10 nM BQ123 group was significantly lower than that in 1 nM ET-1(1-31) group (P < 0.01). The arrhythmia induced by 1 nM ET-1(1-31) was partially but significantly reduced by phosphoramidon (1 microM), a neutral endopeptidase/ET-converting enzyme inhibitor. ET-1(1-31) per se caused arrhythmia in perfused isolated rat hearts. This arrhythmogenic action is in part mediated by ET(A) receptor and may be attributed mainly to the conversion of ET-1(1-31) to ET-1(1-21.).

Animals↗
PubMed2006

[Effect of antitachycardia pacemaker on atrial tachyarrhythmia detection, prevention and termination].

OBJECTIVE: The present study retrospectively evaluated the reliability of detecting atrial tachyarrhythmias (ATA), the efficacy of automatic atrial antitachycardia pacing (ATP) and the performance of atrial preventive pacing (APP) algorithms in an implanted antitachycardia DDDRP pacemaker for patients with sick sinus syndrome and paroxysmal ATA. METHODS: In all 24 patients, a DDDRP pacemaker (Medtronic AT500/AT501) was implanted. APP algorithms were switched on at the implanting physician's discretion. During each pacemaker follow-up, information was saved to disk and the ATA burden between those patients with APP algorithms switched "ON" and "OFF" were compared. Reliability of ATA detection was determined by reviewing the stored electrograms and ATP efficacy was also reviewed. Both the pacemaker memory data and manual EGM retrieval were used for the analysis. RESULTS: Complication-free survival at (17.63 +/- 8.79) months was 100%. In 12 patients APP was not turned "ON" until the latest follow-up, in 6 patients APP was switched "ON" at their first visit after implantation, and in another 6 patients APP was switched "ON" after a median follow-up of 9.29 months. There were 97 367 episodes of ATA detected by the devices, of those with stored atrial electrograms the correct classification of ATA was (76.77 +/- 20.52)%. The percentage of atrial pacing with APP algorithms turned on was (87.95 +/- 20.93)%, which was significantly higher than that in patients with APP "OFF" (50.73 +/- 34.46)% (P < 0.01). ATP efficacy was (50.27 +/- 19.29)%. However, the ATA burden (14.73% vs 16.52%, or 7.52 hours vs 6.58 hours per week, P > 0.05) and the longest duration of single ATA episode (27.27 hours vs 20.75 hours, P > 0.05) were not significantly different between those patients with APP "ON" and "OFF". No proarrhythmic effect or major cardiovascular event was observed. CONCLUSIONS: The antitachycardia DDDRP pacemaker correctly detects and diagnoses about 75% of the ATA episodes, while the ATP therapy successfully terminates atrial tachycardia or flutter in about 50% of attacks. However, there is no difference in ATA burden with the APP algorithms and high incidence of atrial pacing. As a non-curative therapy strategy, this high-cost device may only be used in strictly selected indication patients in addition to other treatments of ATA.

Aged↗
PubMed2006

RAGE on the Toll Road?

Mammalian Toll-like receptors (TLRs) are cellular pattern-recognizing receptors (PRRs) that recognize the molecular patterns of pathogens. After engaging the pathogenic patterned ligands, the cytosolic portion of the TLRs in monocytes and macrophages, recruits adaptor proteins, via a receptor-driven signaling cascade, activates the transcription factor NF-kappaB, leading to the expression of proinflammatory cytokines, which trigger inflammation. Such rapid, innate cellular responses serve as the first line of host defense against infection by pathogens, and also stimulate the adaptive immune system to clear the invading microbes. Increasing evidence suggests that TLRs also recognize host-derived ligands, linking this group of PRRs to diseases that may not have an etiology that is associated directly with infections. Advanced glycation end products (AGEs) are nonenzymatically glycated or oxidated proteins, lipids and nucleic acids that are formed in the environment of oxidant stress and hyperglycemia. Binding of AGEs to their receptor RAGE initiates cellular signals that activate NF-kappaB, which results in transcription of proinflammatory factors. RAGE can also interact with other endogenous ligands generated by cell death and tissue injuries. RAGE has been implicated in chronic diseases such as diabetes, atherosclerosis, neurodisorders, cancers, as well as aging. This review discusses the possible role of RAGE as a PRR that may use signaling mechanisms parallel to TLRs', to solicit inflammatory reactions. Thus, in this scenario, RAGE may play a prominent role in the regulation of cellular homeostasis in the context of complex disease progression.

Animals↗
PubMed2005

Expression of hepatitis B virus S gene in Pichia pastoris and application of the product for detection of anti-HBs antibody.

Antibody to hepatitis B surface antigen (HBsAb) is the important serological marker of the hepatitis B virus (HBV) infection. Conventionally, the hepatitis B surface antigen (HBsAg) obtained from the plasma of HBV carriers is used as the diagnostic antigen for detection of HBsAb. This blood-origin antigen has some disadvantages involved in high cost, over-elaborate preparation, risk of infection, et al. In an attempt to explore the suitable recombinant HBsAg for the diagnostic purpose, the HBV S gene was expressed in Pichia pastoris and the product was applied for detection of HBsAb. Hepatitis B virus S gene was inserted into the yeast vector and the expressed product was analyzed by sodium dodecyl sulphate polyacrolamide gel electrophoresis (SDS-PAGE), immunoblot, electronic microscope and enzyme linked immunosorbent assay (ELISA). The preparations of synthesized S protein were applied to detect HBsAb by sandwich ELISA. The S gene encoding the 226 amino acid of HBsAg carrying a hexa-histidine tag at C terminus was successfully expressed in Pichia pastoris. The His-Tagged S protein in this strain was expressed at a level of about 14.5 % of total cell protein. Immunoblot showed the recombinant HBsAg recognized by monoclonal HBsAb and there was no cross reaction between all proteins from the host and normal sera. HBsAb detection indicated that the sensitivity reached 10 mIu (micro international unit)/ml and the specificity was 100 % with HBsAb standard of National Center for Clinical Laboratories. A total of 293 random sera were assayed using recombinant S protein and a commercial HBsAb ELISA kit (produced by blood-origin HBsAg), 35 HBsAb positive sera and 258 HBsAb negative sera were examined. The same results were obtained with two different reagents and there was no significant difference in the value of S/CO between the two reagents. The recombinant HBV S protein with good immunoreactivity and specificity was successfully expressed in Pichia pastoris. The reagent for HBsAb detection prepared by Pichia pastoris-derived S protein showed high sensitivity and specificity for detection of HBsAb standard. And a good correlation was obtained between the reagent produced by recombinant S protein and commercial kit produced by blood-origin HBsAg in random samples.

Antibodies, Monoclonal↗
PubMed2005

Single nucleotide polymorphisms of the gonadotrophin-regulated testicular helicase (GRTH) gene may be associated with the human spermatogenesis impairment.

BACKGROUND: Gonadotropin-regulated testicular RNA helicase (GRTH) is a testis-specific RNA helicase that is essential for completion of spermatogenesis and is involved in pathogenesis of impaired spermatogenesis in mouse. It is therefore reasonable to postulate that human GRTH gene may also play a role in impaired spermatogenesis in humans. To test this hypothesis, we investigated the possible association between the variations of the GRTH gene and human spermatogenesis impairment. METHODS: Mutation screening of exons and intron/exon boundaries of GRTH gene was carried out by denaturing high-performance liquid chromatography (DHPLC) in 347 infertile patients with idiopathic azoospermia and severe oligozoospermia as well as 201 fertile men. RESULTS: Four single nucleotide polymorphisms (SNP), namely IVS6+55G-->T, ISV8+10A-->C, c.852C-->T and c.927G-->A, were identified. Among them, significant differences in polymorphism frequencies were observed at the polymorphic IVS6+55G-->T and c.852C-->T loci between the patients and controls, and a significant association between haplotypes of these two loci and male infertility with impaired spermatogenesis was detected. CONCLUSIONS: Results of the present study indicate that SNP IVS6+55G-->T and c.852C-->T of GRTH gene may be associated with male infertility with azoospermia or severe oligozoospermia, suggesting that variations in GRTH gene may contribute to susceptibility to spermatogenic impairment in humans.

Base Sequence↗
PubMed2005

The common variant N372H in BRCA2 gene may be associated with idiopathic male infertility with azoospermia or severe oligozoospermia.

OBJECTIVE: To explore the possible association between the common single nucleotide polymorphism N372H in human breast cancer susceptibility gene 2 (BRCA2) and the idiopathic male infertility with azoospermia or severe oligozoospermia. STUDY DESIGN: The study included 240 infertile patients with idiopathic azoospermia or severe oligozoospermia and 250 fathered controls. The allele and genotype frequencies of the polymorphism N372H in BRCA2 gene were investigated in both patients and controls using denaturing high performance liquid chromatography analysis (DHPLC). RESULTS: The frequency of allele H of the polymorphism N372H in patients was significantly higher than that of the controls (23.5% versus 17.6%, OR = 1.49, 95% CI 1.06-1.97, P = 0.02) and the subjects bearing rare allele H (NH + HH) significantly increased in patients compared with controls (41.7% versus 32.4%, 95% CI 1.03-2.15, P = 0.03). CONCLUSION: The results of this study suggested that the polymorphism N372H in BRCA2 gene may be associated with idiopathic male infertility with azoospermia or severe oligozoospermia.

Chromatography, High Pressure Liquid↗
PubMed2005

[Impact of chronic schistosomiasis japonica on the protective immunity induced by vaccine against hepatitis B virus].

OBJECTIVE: To study the impact of chronic schistosomiasis on the protective immunity induced by vaccine against hepatitis B virus. METHODS: 24 patients with chronic or advanced schistosomiasis (experimental group) and 26 healthy volunteers (control group) all without hepatitis B virus infection were selected for the study. Sera of the subjects in the two groups were collected before inoculation and on the 35th day after inoculation with yeast-derived recombinant hepatitis B vaccine. The level of anti-Hbs, IL-2 and TNF-alpha in sera was examined by ELISA respectively. RESULTS: Anti-Hbs in both groups were negative before inoculation, with an average absorbance (A value) of 0.134 and 0.150 respectively. After inoculation, positive rate of anti-Hbs was 17% (4/24, average A value 0.145 ) in experimental group and 92% (24/26, average A value was 1.210) in control group. The vaccine against hepatitis B induced significantly higher level of anti-Hbs in healthy volunteers compared with that in schistosomiasis patients (P < 0.01). The level of IL-2 and TNF-alpha increased in both groups after inoculation without significant difference compared with the level before inoculation. CONCLUSION: The results suggest that the protective immunity of patients with chronic schistosomiasis is deficient to the stimulation of hepatitis B virus and it may involve in a higher incidence of hepatitis B among schistosomiasis patients.

Adult↗
PubMed2005

Variation analysis of the severe acute respiratory syndrome coronavirus putative non-structural protein 2 gene and construction of three-dimensional model.

BACKGROUND: The rapid transmission and high mortality rate made severe acute respiratory syndrome (SARS) a global threat for which no efficacious therapy is available now. Without sufficient knowledge about the SARS coronavirus (SARS-CoV), it is impossible to define the candidate for the anti-SARS targets. The putative non-structural protein 2 (nsp2) (3CL(pro), following the nomenclature by Gao et al, also known as nsp5 in Snidjer et al) of SARS-CoV plays an important role in viral transcription and replication, and is an attractive target for anti-SARS drug development, so we carried on this study to have an insight into putative polymerase nsp2 of SARS-CoV Guangdong (GD) strain. METHODS: The SARS-CoV strain was isolated from a SARS patient in Guangdong, China, and cultured in Vero E6 cells. The nsp2 gene was amplified by reverse transcription-polymerase chain reaction (RT-PCR) and cloned into eukaryotic expression vector pCI-neo (pCI-neo/nsp2). Then the recombinant eukaryotic expression vector pCI-neo/nsp2 was transfected into COS-7 cells using lipofectin reagent to express the nsp2 protein. The expressive protein of SARS-CoV nsp2 was analyzed by 7% sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE). The nucleotide sequence and protein sequence of GD nsp2 were compared with that of other SARS-CoV strains by nucleotide-nucleotide basic local alignment search tool (BLASTN) and protein-protein basic local alignment search tool (BLASTP) to investigate its variance trend during the transmission. The secondary structure of GD strain and that of other strains were predicted by Garnier-Osguthorpe-Robson (GOR) Secondary Structure Prediction. Three-dimensional-PSSM Protein Fold Recognition (Threading) Server was employed to construct the three-dimensional model of the nsp2 protein. RESULTS: The putative polymerase nsp2 gene of GD strain was amplified by RT-PCR. The eukaryotic expression vector (pCI-neo/nsp2) was constructed and expressed the protein in COS-7 cells successfully. The result of sequencing and sequence comparison with other SARS-CoV strains showed that nsp2 gene was relatively conservative during the transmission and total five base sites mutated in about 100 strains investigated, three of which in the early and middle phases caused synonymous mutation, and another two base sites variation in the late phase resulted in the amino acid substitutions and secondary structure changes. The three-dimensional structure of the nsp2 protein was successfully constructed. CONCLUSIONS: The results suggest that polymerase nsp2 is relatively stable during the phase of epidemic. The amino acid and secondary structure change may be important for viral infection. The fact that majority of single nucleotide variations (SNVs) are predicted to cause synonymous, as well as the result of low mutation rate of nsp2 gene in the epidemic variations, indicates that the nsp2 is conservative and could be a target for anti-SARS drugs. The three-dimensional structure result indicates that the nsp2 protein of GD strain is high homologous with 3CL(pro) of SARS-CoV urbani strain, 3CL(pro) of transmissible gastroenteritis virus and 3CL(pro) of human coronavirus 229E strain, which further suggests that nsp2 protein of GD strain possesses the activity of 3CL(pro).

Animals↗
PubMed2005

QSAR analysis of substituted bis[(acridine-4-carboxamide)propyl]methylamines using optimized block-wise variable combination by particle swarm optimization for partial least squares modeling.

In the current work, we employed optimized block-wise variable combination (OBVC) by particle swarm optimization (PSO) based on partial least squares (PLS) modeling for variable combination and compared it to the traditional methods. It has been demonstrated that the modified PSO is a useful tool for searching optimized variable combination. Quantitative structure-activity relationship (QSAR) model has been formulated for a set of DNA binding topoisomerase (topo) (substituted bis[(acridine-4-carboxamide)propyl]methylamines) on murine Lewis lung carcinoma (LL(c)) cells. The spatial descriptors especially Jurs descriptors play important roles in predicting the compound's inhibitory activity to murine LL(c) cells, and polar interactions are the principal binding strength between compounds and murine LL(c) cells. In addition, rotatable bonds in molecules and molar refractivity of the compounds will markedly affect the compounds' inhibitory activity.

Acridines↗
PubMed2005

Clinical and biological features associated with epidermal growth factor receptor gene mutations in lung cancers.

BACKGROUND: Mutations in the tyrosine kinase (TK) domain of the epidermal growth factor receptor (EGFR) gene in lung cancers are associated with increased sensitivity of these cancers to drugs that inhibit EGFR kinase activity. However, the role of such mutations in the pathogenesis of lung cancers is unclear. METHODS: We sequenced exons 18-21 of the EGFR TK domain from genomic DNA isolated from 617 non-small-cell lung cancers (NSCLCs) and 524 normal lung tissue samples from the same patients and 36 neuroendocrine lung tumors collected from patients in Japan, Taiwan, the United States, and Australia and from 243 other epithelial cancers. Mutation status was compared with clinicopathologic features and with the presence of mutations in KRAS, a gene in the EGFR signaling pathway that is also frequently mutated in lung cancers. All statistical tests were two sided. RESULTS: We detected a total of 134 EGFR TK domain mutations in 130 (21%) of the 617 NSCLCs but not in any of the other carcinomas, nor in nonmalignant lung tissue from the same patients. In NSCLC patients, EGFR TK domain mutations were statistically significantly more frequent in never smokers than ever smokers (51% versus 10%), in adenocarcinomas versus cancer of other histologies (40% versus 3%), in patients of East Asian ethnicity versus other ethnicities (30% versus 8%), and in females versus males (42% versus 14%; all P < .001). EGFR TK domain mutation status was not associated with patient age at diagnosis, clinical stage, the presence of bronchioloalveolar histologic features, or overall survival. The EGFR TK domain mutations we detected were of three common types: in-frame deletions in exon 19, single missense mutations in exon 21, and in-frame duplications/insertions in exon 20. Rare missense mutations were also detected in exons 18, 20, and 21. KRAS gene mutations were present in 50 (8%) of the 617 NSCLCs but not in any tumors with an EGFR TK domain mutation. CONCLUSIONS: Mutations in either the EGFR TK domain or the KRAS gene can lead to lung cancer pathogenesis. EGFR TK domain mutations are the first molecular change known to occur specifically in never smokers.

Adenocarcinoma↗
PubMed2005

Evidence from nature: interspecies spread of heron hepatitis B viruses.

Heron hepatitis B viruses (HHBVs) in three subspecies of free-living great blue herons (Ardea herodias) from Florida, USA, were identified and characterized. Eight of 13 samples were positive in all assays used, whereas sera from egrets, which are also members of the family Ardeidae, were negative in the same assays. Comparative phylogenetic analysis of viral DNA sequences from the preS/S region of previously reported and novel HHBV strains isolated from captive grey herons (Germany) and free-ranging great blue herons (USA), respectively, revealed a strong conservation (95 % sequence similarity) with two separate clusters, implying a common ancestor of all strains. Our data demonstrate for the first time that different subspecies of herons are infected by HHBV and that these infections exist in non-captive birds. Phylogenetic analysis and the fact that the different heron species are geographically isolated populations suggest that lateral transmission, virus adaptation and environmental factors all play a role in HHBV spreading and evolution.

Animals↗
PubMed2005

Occupational safety and health in china, part I: u.s.-China symposium on "integrating occupational and environmental health".

A joint China-U.S. symposium entitled "Integrating Occupational and Environmental Health" was organized by the Department of Science and Technology of Hebei Province, PRC, and the Department of Work Environment at the University of Massachusetts Lowell, U.S.A. A framework called "Sustainable Production" was proposed by U.S. participants to link environmental and worker protection. Sustainable production focuses on systems of production that integrate concerns for the long-term viability of the environment, worker health and safety, the community, and the economic performance of firms and other enterprises. The disciplines of environmental and occupational health and safety were brought together by Chinese participants under the unifying theme of the development, implementation, and impact of new technologies. As production processes are increasingly concentrated in China, collaboration among U.S. and Chinese environmental and occupational health and safety professionals is ever more essential.

Journal Article↗
PubMed2005

[Influence of cryoprotectant with glycerol and freezing-thawing procedure on the motility of human sperm].

OBJECTIVE: To investigate the effects of cryoprotectant with glycerol and the freezing-thawing procedure on the motility of METHODS: The motion characteristics of human sperm from 18 selected specimens were assessed by computer-assisted human sperm. sperm analysis before and after adding hyper-osmolarity cryoprotectant with glycerol and the freeze-thaw procedure, and the data were evaluated in pairs. RESULTS: The adding of cryoprotectant caused an increase in the proportion of rapid linear motile sperms (P < 0.05) and sperm velocities, including VCL, VSL and VAP (P < 0.005). But no changes were observed in the proportion of progressively motile sperms and sperm motility. Compared with the data from pre-frozen samples, velocities of post-thawed sperms and the percentage of motile sperms in each grade significantly declined (P < or = 0.01), so did ALH, while WOB, LIN and STR remained unchanged (P > 0.05). Significant differences in ALH, WOB, LIN and STR were observed only in comparison between the post-thawed and pre-treated samples. CONCLUSION: The number of Grade a sperms and sperm velocity increased after adding hyper-osmolarity cryoprotectant with glycerol. The sperm motile potential was impaired and even entirely destroyed in some cases by cryodamage. The influences on the sperm motion were differently induced in freezing-thawing procedures.

Cryopreservation↗
PubMed2005

[The changes of apoptosis and proliferation of pulmonary tissue in chronic obstructive pulmonary disease rats].

OBJECTIVE: To observe the changes of apoptosis and proliferation of pulmonary tissue cells in rats with chronic obstructive pulmonary disease (COPD). METHODS: The rat model of COPD was established by exposure to cigarette smoking. Thirty-three Wistar rats were randomly divided into a normal control (NC) group, a smoking inhalation for 1 month (COPD-1) group and a smoking inhalation for 2 month (COPD-2) group. Pathologic changes of lung tissues and inflammatory cell differentials were studied. Immunohistochemistry and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) methods were carried out to examine the percentage of positive cells and distribution of apoptotic cells and proliferating cells in the lung tissue. RESULTS: Significant increases in total leukocyte numbers and neutrophils in the bronchoalveolar lavage were found in the COPD groups as compared to NC group. Two months after smoking exposure, enlargement of airspaces distal to the terminal bronchiole, destruction of alveolar walls, and loss of the alveolar unit were observed. The percentage of apoptotic cells of airway epithelium, alveolar wall cell and vascular smooth muscle cells were (36.2 +/- 8.5)%, (32.7 +/- 6.4)%, (16.1 +/- 7.2)% in COPD-1 group; (39.5 +/- 9.3)%, (37.3 +/- 7.6)%, (21.4 +/- 6.5)% in COPD-2 group; the difference being significant (all P < 0.01), as compared with NC group [(5.8 +/- 1.7)%, (6.1 +/- 2.3)%, (4.9 +/- 1.4)%]. The percentage of proliferative cells of airway epithelium, alveolar wall cell and vascular smooth muscle cells were (33.4 +/- 6.3)%, (30.1 +/- 4.6)%, (28.4 +/- 6.3)% in COPD-1 group; (35.5 +/- 9.8)%, (33.2 +/- 7.7)%, (34.5 +/- 6.7)% in COPD-2 group; the difference being significant (all P < 0.01), as compared with NC group [(7.4 +/- 2.3)%, (5.2 +/- 2.1)%, (4.4 +/- 1.8)%]. The numbers of apoptotic and proliferating cells were significantly higher in the COPD-2 group than those in the COPD-1 group (all P < 0.01). The ratio of proliferative index (PI)/apoptotic index (AI) of the pulmonary tissue cells were also different. The ratio of PI/AI of airway epithelium in COPD-1 and COPD-2 group [(0.82 +/- 0.13)%, (0.78 +/- 0.24)%] was much lower than NC group [(1.12 +/- 0.23)%, P < 0.05]; The ratio of PI/AI in small pulmonary vessels in the COPD groups [(1.55 +/- 0.25)%, (1.47 +/- 0.28)%] was significantly higher than NC group [(0.92 +/- 0.05)%, P < 0.05]. CONCLUSION: The changes of apoptosis and proliferation of pulmonary tissue in COPD rats might contribute to the pathogenesis of COPD.

Animals↗
PubMed2005

[Important genetic etiology of infertile Chinese males: chromosome abnormality and deletion of DAZ gene copy in the AZFc region of Y chromosome].

OBJECTIVE: To investigate the correlation of male infertility with abnormality of chromosomal quantity and construction and with the deletion of DAZ gene copy in the AZFc region of Y chromosome. METHODS: Included in the study were 247 azoospermic and 206 severe oligozoospermic patients, as well as 210 fertile men as controls. Multi-PCR and PCR-RFLP were used to analyze the deletion of DAZ gene copies in the AZFc region of Y chromosome. Chromosomal quantity and construction were detected by G-band in the 453 patients. RESULTS: In the azoospermic and severe oligozoospermic patients, the incidences of chromosomal abnormality were 12.6% and 8.3%; the rates of complete DAZ deletion were 7.7% and 11.2%, and the rates of DAZ1/DAZ2 deletion were 7.3% and 4.9% respectively, but no deletion was detected in the controls. CONCLUSION: There is a high frequency of chromosomal abnormality and DAZ gene copy deletion in patients with azoospermia and oligospermia, which suggests that chromosomal abnormality and partial and complete deletion of DAZ gene copy might be important genetic causes of Chinese male infertility.

China↗