High risk genetic factor in Chinese patients with idiopathic male infertility: deletion of DAZ gene copy on Y chromosome.
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Chromosomes, Human, Y↗
Biomedical subjects
Li Lin
Publications and source records attributed to Li Lin.
[Tetrahydrobiopterin and endothelial dysfunction].
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Animals↗
[Idiopathic male infertility and partial copy deletion of DAZ gene family].
OBJECTIVE: To analyze the pattern and prevalence of partial copy deletion of deleted-in-azoospermia (DAZ) gene in the azoospermia factor C(AZFc) region of patients with idiopathic azoospermia or severe oligozoospermia. METHODS: sY581 and sY587 in DAZ gene region were analyzed by polymerase chain reaction-restriction length polymorphism(PCR-RFLP) for its deletion in 197 patients with azoospermia, 166 patients with severe oligozoospermia, and 210 fertile men as controls. RESULTS: Deletion of both DAZ1 and DAZ2 was detected in 18 patients with azoospermia and 10 with severe oligozoospermia, and the prevalence was 9.1% and 6.0% respectively. There was significant difference in deletion rate between the cases and controls. CONCLUSION: The frequency of partial copy deletion of DAZ gene in Chinese idiopathic azoospermia or severe oligozoospermia patients is much higher than that of fertile controls, suggesting that the deletion of DAZ1/DAZ2 may be one of the important genetic etiological factors of spermatogenesis damage. The pattern and prevalence of DAZ partial copy deletion are similar to those of Caucasians populations, and detection of DAZ gene partial copy deletion by PCR-RFLP may be adopted as an additional clinical gene diagnostic measure after AZF microdeletion detection.
Azoospermia↗
Quantitative (stereological) study of incomplete spermatogenic suppression induced by testosterone undecanoate injection in rats.
AIM: To evaluate the key lesions in spermatogenesis suppressed partially by testosterone undecanoate (TU) treatment. METHODS: Adult male SD rats were treated with vehicle or TU (19 mg/kg) injection (i.m.) every 15 days for 130 days. The numbers of all types of cells (nuclei) in the seminiferous tubules and the interstitial tissue were estimated using a contemporary stereological tool, the optical disector. RESULTS: In response to TU treatment, the numbers of non-type B spermatogonia, type B spermatogonia and late elongated spermatids per testis were reduced to 51 %, 66 % and 14 % of the controls, respectively. The conversion ratios from type B spermatogonia to early spermatocytes and pachytene spermatocytes were not significantly affected and the ratios to the later germ cell types fell to 51 % - 65 % of the controls. Less than 1.0 % of immature round spermatids were seen sloughing into the tubule lumen, 4.0 % of elongated spermatids retained in the seminiferous epithelium, and about half of the elongated spermatid nuclei appreciably malformed. Leydig cells were atrophied but their number and the peritubular myoid cell number per testis were unchanged. CONCLUSION: Double inhibition of spermatogenesis (i.e. inhibition at spermiation and spermatogonial conversion to type B spermatogonia), a scenario seen in the monkey and human following gonadotrophin withdrawal, was not sufficiently effective for a complete spermatogenic suppression in the rat after TU treatment, probably due to ineffective inhibition of the Leydig cell population and therefore the intra-testicular testosterone levels.
Animals↗
[Study on coumarin compounds from Exocarpium Citri Grandis].
OBJECTIVE: To study the coumarin compounds from Exocarpium Citri Grandis. METHOD: The constituents were isolated by column chromatograph and identified by spectral data. RESULT: Two coumarin compounds were isolated from the non-volatile section of Exocarpium Citri Grandis and identified as isoimperator and bergapten. CONCLUSION: The two compounds were isolated from the plant for the first time.
5-Methoxypsoralen↗
[Clinical analysis on the bone marrow cell picture of benzene-induced acute monocytic leukemia].
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Adult↗
Up-regulation of endothelial nitric-oxide synthase by endothelium-derived hyperpolarizing factor involves mitogen-activated protein kinase and protein kinase C signaling pathways.
Cytochrome P450 (P450)-dependent metabolites of arachidonic acid, the epoxyeicosatrienoic acids (EETs), are proposed to be endothelium-derived hyperpolarizing factors (EDHF) that affect vascular tone; however, the effects of EDHF on endothelial-derived nitric oxide biosynthesis remain unknown. We examined the regulation of endothelial nitric-oxide synthase (eNOS) by EDHF and investigated the relevant signaling pathways involved. The P450 epoxygenases CYP102 F87V mutant, CYP2C11-CYPOR, and CYP2J2 were transfected into cultured bovine aortic endothelial cells, and the effects of endogenously formed or exogenously applied EETs on eNOS expression and activity were assessed. Transfection with the P450 epoxygenases led to increased eNOS protein expression, an effect that was attenuated by cotreatment with the P450 inhibitor 17-ODYA. Northern analysis demonstrated that P450 transfection led to increased eNOS mRNA levels consistent with an effect at the pretranslational level. P450 epoxygenase transfection resulted in increased eNOS activity as measured by the conversion of L-arginine to L-citrulline. Addition of synthetic EETs (50-200 nM) to the culture media also increased eNOS expression and activity. Treatment with mitogen-activated protein kinase (MAPK), MAPK kinase, and protein kinase C inhibitors apigenin, 2'-amino-3'-methoxyflavone (PD98059), and 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H-7), respectively, significantly inhibited the effects of P450 transfection on eNOS expression. Overexpression of P450 epoxygenases or addition of synthetic EETs increased Thr495 phosphorylation of eNOS, an effect that was inhibited by both apigenin and PD98059. Overexpression of P450 epoxygenases in rats resulted in increased aortic eNOS expression, providing direct evidence that EDHF can influence vascular eNOS levels in vivo. Based on this data, we conclude that EDHF up-regulates eNOS via activation of MAPK and protein kinase C signaling pathways.
Animals↗
[Effects of urotensin II on isolated rat hearts under normal perfusion and ischemia reperfusion].
To shed light on cardiac effects of the potent vasoconstrictive peptide urotensin II (U II), Langendorff-perfused isolated rat hearts were consecutively perfused with 0.1, 1 and 10 nmol/L U II, for 5 min at each dose, followed by 5-min washout. Moreover, isolated hearts subjected to 20-min global no-flow ischemia were reperfused with U II (1 or 10 nmol/L) for 20 min. Heart function parameters including heart rate, left ventricular pressure and dP/dt were monitored; content of protein and myoglobin, and activity of lactate dehydrogenase (LDH) in coronary effluent were determined; malondialdehyde (MDA) in myocardium and [(125)I]-U II binding sites in plasma membrane were measured after the completion of perfusion. The results showed that: (1) In normal rat hearts, the coronary flow was decreased and the heart function was suppressed by U II dose-dependently, and these changes were not abolished by washout. The leakage of cardiac protein, myoglobin and LDH increased with the increment of U II, but it diminished rapidly after washout. In contrast, MDA content in U II -treated myocardium was not statistically different from that in normal myocardium. (2) Ischemia-reperfusion caused significant decreases in coronary flow, suppression of heart function, and leakage of protein and LDH. In U II -reperfused hearts, all these disorders were significantly aggravated and myocardial MDA content significantly increased (P<0.01), to a greater extent in the presence of higher dose of U II. (3) The maximal binding capacity (B(max)) of U II receptors in plasma membrane from ischemia-reperfusion myocardium increased significantly as compared with that of normal myocardium (20.53+/-1.98 vs 14.65+/-1.78 fmol/mg pr, P<0.01), while Kd remained unchanged. These results indicate that U II caused injury to the isolated rat hearts under normal perfusion, and worsened the injury of the hearts under ischemia-reperfusion, in which U II receptors were up-regulated.
Animals↗
Study of the interaction of 6-mercaptopurine with protein by microdialysis coupled with LC and electrochemical detection based on functionalized multi-wall carbon nanotubes modified electrode.
Microdialysis sampling coupled with liquid chromatography and electrochemical detection (LC-ECD) was developed and applied to study the interaction of 6-Mercaptopurine (6-MP) with bovine serum albumin (BSA). In the LC-ECD, the multi-wall carbon nanotubes fuctionalized with carboxylic groups modified electrode (MWNT-COOH CME) was used as the working electrode for the determination of 6-MP. The results indicated that this chemically modified electrode (CME) exhibited efficiently electrocatalytic oxidation for 6-MP with relatively high sensitivity, stability and long-life. The peak currents of 6-MP were linear to its concentrations ranging from 4.0 x 10(-7) to 1.0 x 10(-4) mol l(-1) with the calculated detection limit (S/N = 3) of 2.0 x 10(-7) mol l(-1). The method had been successfully applied to assess the association constant (K) and the number of the binding sites (n) on a BSA molecular, which calculated by Scatchard equation, were 3.97 x 10(3) mol(-1) l and 1.51, respectively. This method provided a fast, sensible and simple technique for the study of drug-protein interactions.
Catalysis↗
Stability of the Rel homology domain is critical for generation of NF-kappa B p50 subunit.
The NF-kappa B transcription factor p50 and the Rel protein-specific transcription inhibitor p105 are both encoded by the nfkb1 gene. The p50 protein is incorporated within the N-terminal portion of p105 and is a unique product of proteasomal processing. Because proteasome-mediated proteolysis generally results in complete degradation of the substrate, how p50 survives the proteasomal processing remains unknown. Survival of proteasomal processing has also been observed recently for the yeast transcription factors SPT23 and MGA2, but the mechanism is also unclear. Here we show evidence that stability of the Rel homology domain (RHD) within the N-terminal portion of the NF-kappa B 1 protein is required for p50 generation. We demonstrated that proteolysis initiated at an internal location of the NF-kappa B 1 protein, which normally generates p50, degrades the N-terminal portion of the NF-kappa B 1 protein when the RHD is destabilized. Our findings highlight the critical role of the unique structure of the RHD for the survival of p50 during proteosomal processing.
Adenosine Triphosphatases↗
Efficient linking and transfer of multiple genes by a multigene assembly and transformation vector system.
Introduction and expression of multiple transgenes is frequently required for basic and applied studies. However, at present, multigene transformation is very difficult due to technical limitations of existing methods. Here, we describe a vector system for efficient multigene assembly and transformation. The system consists of a transformation-competent artificial chromosome (TAC)-based acceptor vector together with two donor vectors. By exploiting the CreloxP recombination system and homing endonucleases, multiple rounds of gene assembly cycling were carried out with alternate use of the donor vectors, and multiple genes were sequentially delivered into the TAC vector. With this system, we created constructs containing as many as 10 foreign DNA fragments. Multiple genes, including six resistant genes stacked in a construct, were transferred into rice genome by Agrobacterium-mediated transformation. This system extends the repertoire of molecular genetic studies and biotechnological endeavors by enabling simultaneous manipulation of multiple genes.
Agrobacterium tumefaciens↗
[Preventive effect of endothelin-1 pretreatment on hypoxia-induced injury in cultured neonatal rat cardiomyocytes].
This study was designed to observe the effects of endothelin-1 (ET-1) pretreatment on hypoxia-induced injury and changes in [Ca(2+)](i) in cultured neonatal rat cardiomyocytes. The activity of lactate dehydrogenase (LDH) and superoxide dismutase (SOD), and the content of malondialdehyde (MDA) in the supernatant were determined in the cultured cardiomyocytes subjected to a 12-h hypoxia induced by a 3% O(2)-5% CO(2) atmosphere at 37 with or without ET-1 pretreatment. [Ca(2+)](i) was measured with Ca(2+)-sensitive fluorescent probe fluo-3/AM under a laser scanning confocal microscope. Fluorescence intensity emitted from fluo-3/AM-loaded cells reflected the concentration of [Ca(2+)](i). The hypoxia model used in [Ca(2+)](i) measurement was established by continously perfusing cardiomyocytes for 30 min with 95% N(2)-5% CO(2) saturated DMEM solution containing 1 mmol/L Na(2)S(2)O(4). Pretreatment with ET-1 consisted of three cycles of ET-1 perfusion (5 min for each) followed by ET-1-free DMEM solution (10 min for each) prior to hypoxia. The results showed that (1) after incubation in a 3% O(2)-5% CO(2) hypoxic atmosphere for 12 h, the activity of LDH and the content of MDA in the supernatant significantly increased from 19.33+/-1.03 U/L to 43.33+/-1.21 U/L and from 0.91+/-0.03 nmol/L to 1.71+/-0.02 nmol/L, respectively, whereas the activity of SOD decreased from 33.48+/-1.15 U/ml to 16.93+/-1.11 U/ml (P<0.01). In hypoxic cardiomyocytes pretreated with 0.01-1 nmol/L ET-1, LDH release and supernatant MDA content were decreased, while SOD activity was enhanced dose-dependently (P<0.01). (2) The spontaneous calcium transient in cultured cardiomyocytes terminated at 29+/-1.5 s and [Ca(2+)](i) increased by 107+/-13.2% during perfusion of hypoxic solution (P<0.001) at the end of 30 min. ET-1 (0.01-1 nmol/L) increased the frequency of [Ca(2+)](i) transient in cultured cardiomyocytes in a dose-dependent manner (P<0.01). The termination of [Ca(2+)](i) transient and the elevation of [Ca(2+)](i) caused by hypoxia were postponed by pretreatment with 0.01-1 nmol/L ET-1 (P<0.01). These results show that pretreatment with 0.01-1 nmol/L ET-1 attenuates hypoxia-induced injury and [Ca(2+)](i) changes in cultured neonatal cardiomyocytes, indicating a cyto-protective role of ET-1 pretreatment.
Animals↗
Binding site for p120/delta-catenin is not required for Drosophila E-cadherin function in vivo.
Homophilic cell adhesion mediated by classical cadherins is important for many developmental processes. Proteins that interact with the cytoplasmic domain of cadherin, in particular the catenins, are thought to regulate the strength and possibly the dynamics of adhesion. beta-catenin links cadherin to the actin cytoskeleton via alpha-catenin. The role of p120/delta-catenin proteins in regulating cadherin function is less clear. Both beta-catenin and p120/delta-catenin are conserved in Drosophila. Here, we address the importance of cadherin-catenin interactions in vivo, using mutant variants of Drosophila epithelial cadherin (DE-cadherin) that are selectively defective in p120ctn (DE-cadherin-AAA) or beta-catenin-armadillo (DE-cadherin-Delta beta) interactions. We have analyzed the ability of these proteins to substitute for endogenous DE-cadherin activity in multiple cadherin-dependent processes during Drosophila development and oogenesis; epithelial integrity, follicle cell sorting, oocyte positioning, as well as the dynamic adhesion required for border cell migration. As expected, DE-cadherin-Delta beta did not substitute for DE-cadherin in these processes, although it retained some residual activity. Surprisingly, DE-cadherin-AAA was able to substitute for the wild-type protein in all contexts with no detectable perturbations. Thus, interaction with p120/delta-catenin does not appear to be required for DE-cadherin function in vivo.
Animals↗
[Protective strategy of vascular endothelium].
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Angiotensin-Converting Enzyme Inhibitors↗
Gene identification and expression analysis of 86,136 Expressed Sequence Tags (EST) from the rice genome.
Expressed Sequence Tag (EST) analysis has pioneered genome-wide gene discovery and expression profiling. In order to establish a gene expression index in the rice cultivar indica, we sequenced and analyzed 86,136 ESTs from nine rice cDNA libraries from the super hybrid cultivar LYP9 and its parental cultivars. We assembled these ESTs into 13,232 contigs and leave 8,976 singletons. Overall, 7,497 sequences were found similar to existing sequences in GenBank and 14,711 are novel. These sequences are classified by molecular function, biological process and pathways according to the Gene Ontology. We compared our sequenced ESTs with the publicly available 95,000 ESTs from japonica, and found little sequence variation, despite the large difference between genome sequences. We then assembled the combined 173,000 rice ESTs for further analysis. Using the pooled ESTs, we compared gene expression in metabolism pathway between rice and Arabidopsis according to KEGG. We further profiled gene expression patterns in different tissues, developmental stages, and in a conditional sterile mutant, after checking the libraries are comparable by means of sequence coverage. We also identified some possible library specific genes and a number of enzymes and transcription factors that contribute to rice development.
Arabidopsis↗
Isolation and characterization of 70 novel microsatellite markers from ostrich (Struthio camelus) genome.
Microsatellite markers are widely used in linkage mapping, parentage testing, population genetic studies, and molecular evolution studies in many agricultural species, while only a limited number of ostrich (Struthio camelus) microsatellites have been isolated. Thus, we constructed a random small-insert genomic library and a microsatellite-enriched library containing CA repeats. Fourteen clones containing CA repeats were isolated from 3462 clones in the non-enriched library by radioactive screening and 248 positive clones were isolated from 300 sequenced clones from the enriched library by PCR screening. After the enrichment procedures, the proportion of clones containing CA repeats was raised to 78.8%, compared with 0.4% in the non-enriched libraries, indicating that the enrichment value approaches 200 fold, which decreased the time and cost of cloning. The number of complete simple CA repeats in these positive clones ranged from 5 to 29. The primers for 94 of these microsatellites were developed and used to detect polymorphisms, of which 61 loci exhibited length polymorphisms in 17 unrelated ostrich individuals. The new polymorphic microsatellite markers we have identified and characterized will contribute to the ostrich genetic map, parentage testing, and comparative genomics between avian species.
Animals↗
Antiarrhythmic effect of endothelin-A receptor antagonist on acute ischemic arrhythmia in isolated rat heart.
AIM: To observe the effects of endothelin receptor subtype A (ETA) and B (ETB) antagonists on acute ischemic arrhythmia in isolated rat heart, and to determine whether endogenous endothelin (ET) was implicated in the pathophysiological process of arrhythmia induced by acute myocardial ischemia. METHODS: Fifty-three SD male rats were randomized into 8 groups. Heart was isolated and perfused in Langendorff mode and acute ischemia model was established by ligation of the left anterior descending (LAD) coronary artery. The effects of ETA receptor antagonist PD156707 and ETB receptor antagonist IRL1038 on arrhythmia, heart function, the myocardial activity of superoxide dismutase (SOD), and the content of melondialdehyde (MDA) during the acute 60-min ischemic phase were analyzed. RESULTS: Pretreatment with PD156707 (20-500 nmol/L) dose-dependently improved the ischemic isolated heart function, enhanced SOD activity and decreased MDA content in the ischemic myocardium, and suppressed the acute ischemic arrhythmia. Conversely pretreatment with IRL1038 did not change the heart function, SOD activity, MDA content, and the acute ischemic arrhythmia significantly as compared with the occlusion control. CONCLUSION: ETA receptor antagonist effectively improved heart function, enhanced anti-oxidative function of the myocardium and reduced arrhythmia during the acute ischemic phase in isolated rat hearts, while ETB receptor antagonist did not exert protective effects, suggesting that endogenous ET-1, acting through ETA receptor, may be one of the factors implicated in arrhythmia and impairment to heart function during the acute ischemic phase.
Animals↗
[Relationship between acid-base disturbance in blood gas analysis and prognosis of patients with severe acute respiratory syndrome].
OBJECTIVE: To study the influence of the acute blood gas analysis index change on the prognosis of patients with severe acute respiratory syndrome (SARS). METHODS: Artery blood gas analysis indexes were determined in 38 of 103 cases of SARS patients during acute stage, the relationship between the change of blood gas analysis index and prognosis of patients with SARS was analyzed. RESULTS: The lower partical pressure of carbon dioxide in artery (PaCO2), partical pressure of oxygen in artery (PaO2) in blood was, the higher death rate was. pH in blood had no significant influence on the prognosis of SARS patients. The prognosis of SARS patients were worse and the death rate was higher when patient had two or more acid-base disturbance. CONCLUSION: The artery blood gas analysis is useful for judging the conditions and prognosis of patients with SARS, and is beneficial for clinical treatment.
Acid-Base Imbalance↗