Biomedical subjects

Zhen Wang

Publications and source records attributed to Zhen Wang.

At least 55 records · Page 3Linked to original sources

PubMed2006

[The role of subtypes of voltage-gated K+ channels in pulmonary vasoconstriction induced by 15-hydroeicosatetraenoic acid].

AIM: To observe the effect of subtypes of Kv channels in rat pulmonary artery smooth muscle cells (PASMCs) on the process of pulmonary vasoconstriction induced by 15-HETE. METHODS: In the present study, ring of rabbit PA with specific Kv channel blockers were employed to functionally identify certain channel subtypes that took part in the process of 15-HETE induced pulmonary vasoconstriction; RT-PCR and Western blotting analysis were also used to measure the expression of subtypes of Kv in PASMCs exposed to 15-HETE,chronic hypoxia. RESULTS: Blocking of Kv1. 1, Kv1. 2, Kv1. 3 and Kv1. 6 channels did not affect 15-HETE induced vasoconstriction in normoxic rats; 15-HETE did not affect expression of Kv1. 1 and Kv1. 2 channels; 15-HETE significantly downregulated the expression of mRNA and protein of Kv1. 5 and Kv2. 1 in rat PASMCs. CONCLUSION: The results suggested that hypoxia may block Kv1. 5 and Kv2. 1 channels via 15-HETE mediated mechanism, leading to decrease numbers of functional Kv1. 5 and Kv2. 1 channels in PASMCs, leading to PA vasoconstriction.

Animals↗

PubMed2006

[The experiment of porcine keratinocytes cultured on porcine small intestinal submucosa in vitro].

OBJECTIVE: To investigate the feasibility of acellular porcine small intestinal submucosa (SIS as bioscaffold of tissue engineering skin. METHODS: The second passage keratinocytes were seeded on SIS, after seeded for 11, 13, 15, 17 days, the keratinocytes/SIS composites were observed by dye directly, histopathology, immunohistochemical studies with monoclonal antibodies against laminin and transmission electron microscope (TEM). RESULTS: At eleventh day, keratinocytes were growth very well on the surface of SIS, there are 2-3 cell layers on partial of the SIS surface, the continued expression of laminin can be detected between the keratinocytes and the surface of SIS. After 13, 15, 17 days this stratified structure increased, cells contact more closely, the tonofibrils in cells, desmosome between cells and the basal membrane between the keratinocytes and the surface of SIS can be seen with TEM. CONCLUSIONS: SIS is a kind of good bioscaffold in the culture of porcine keratinocytes in vitro.

Animals↗

PubMed2006

[Study on fabrication of controllable microchannel structure scaffolds and rotating dynamic culture].

It is the critical technology for bone tissue engineering to fabricate scaffolds, especially to fabricate the internal microchannel of scaffolds. Utilizing stereolithography rapid prototyping indirect fabrication approach, suitable size microchannel structure scaffolds with orientation, branching, and interconnectivity under control was manufactured. Observation under light microscope showed that the arrange of microchannel size was 200-600 microm, the orientation and branching were accorded with designed structure, and all the microchannels were completely interconnected. Scaffolds seeded with osteoblast cells were put into 6-well plate and rotating 3D dynamic culture system which was developed in our lab. The morphology of osteoblasts and the development on the surface and internal microchannel of scaffolds were observed under scanning electron microscope (SEM). The results indicated that the dynamic culture permited an even distribution of cells across the surface of scaffolds, besides, a few cells grew into the lumen of microchannels.

Animals↗

PubMed2006

[Gene construction, expression and activities analysis of human leptin].

Six 89bp primers were designed on the base of the cDNA sequence encoding the human leptin reported on the NCBI. The synthetic gene with 464bp encoding rhLep was obtained by SOE ( splicing by overlap extension) PCR. The expression vector pET22b(+)/rhLep was constructed and transformed into E. coli BL21 (DE3). The rhLep protein was expressed as inclusion bodies with the yield of more than 50% of total bacterial proteins after IPTG induction. The rhLep protein, which has a molecular weight about 16kD, was purified by Ni2+ affinity chromatography column and identified by SDS-PAGE. The MTT Assay shows that rhLep promotes EC304 cells growth at the low concentration of 10ng/mL to 30 ng/mL, and rhLep appears cytotoxic to EC304 cells with the high dose of 50ng/mL to 225ng/mL. The viability of EC304 cells decreases to 1.2% with the concentration of 225ng/mL of rhLep. The massive apoptosis of rhLep on EC304 cells is observed by AO-staining under fluorescent microscope. All these results would lay the foundation for the further study of its biological functions in vitro and in vivo.

Apoptosis↗

PubMed2006

[Clinicopathologic and immunohistochemical study of atypical teratoid/rhabdoid tumor of central nervous system].

OBJECTIVE: To study the clinicopathologic features and differential diagnosis of atypical teratoid/rhabdoid tumor (AT/RT) occurring in the central nervous system. METHODS: Two cases of AT/RT were studied by hematoxylin-eosin, reticulin and immunohistochemical staining. The clinical and pathologic features were analyzed and the literatures reviewed. RESULTS: Histologically, AT/RT was characterized by the presence of rhabdoid cells associated with various degrees of primitive neuroectodermal, epithelial or mesenchymal differentiation. Abundant reticulin fibers and a complex immunophenotype were observed. The tumor cells were positive for vimentin, CD99, epithelial membrane antigen, cytokeratin, glial fibrillary acidic protein, S-100 protein, neurofilament, desmin and smooth muscle actin. They were negative for synaptophysin, MyoD1, placental alkaline phosphatase and HMB45. CONCLUSIONS: AT/RT is a highly malignant tumor occurring in the central nervous system. It manifests mainly in children and occasionally in adults. The tumor is characterized by a heterogeneous histologic and immunohistochemical phenotype. It needs to be distinguished from a number of central nervous system tumors, including medulloblastoma, primitive neuroectodermal tumor, germ cell neoplasm and rhabdoid meningioma.

12E7 Antigen↗

PubMed2006

[Use of intraoperative round window electrocochleography for assessment of cochlear implantation safety].

OBJECTIVE: To objectively evaluate whether cochlear implantation surgery made damage to cochlear basal membrane or not through analyzing the change of the threshold of cochlear microphonic (CM) of round window electrocochleography before and after inserting electrode during cochlear implantation surgery. METHOD: Round window electrocochleography was performed on 40 cases with profound sensorineural deafness under general anesthesia in the standard operating room in order to analyze the change of the threshold of cochlear microphonic (CM) of round window electrocochleography before and after inserting electrode during cochlear implantation surgery. RESULT: Among the 40 cases, thresholds of cochlear microphonic (CM) before and after inserting electrode during cochlear implantation surgery were similar in 39 cases. The thresholds of cochlear microphonic (CM) after inserting electrode decreased about 5 dB at certain frequency. The thresholds of cochlear microphonic (CM) after inserting electrode increased 20-50 dB in only one case. There was a sense of resistance in implanting the electrodes in this patient. CONCLUSION: Use of round window electrocochleography may objectively evaluate whether cochlear implantation surgery make damage to cochlear basal membrane or not.

Adolescent↗

PubMed2005

Expression and regulation of glucocorticoid receptor in human placental villous fibroblasts.

The human placenta is a glucocorticoid (GC)-responsive organ consisting of multiple cell types including smooth muscle cells, fibroblasts, and trophoblast that demonstrate changes in gene expression after hormone treatment. However, little is known about the relative expression or activity of the GC receptor (GR) among the various placental cell types. Normal term human placentas were examined by immunohistochemistry using either GR phosphorylation site-specific antibodies that are markers for various activation states of the GR or a GR antibody that recognizes the receptor independent of its phosphorylation state (total GR). We found strong total GR and phospho-GR immunoreactivity in stromal fibroblasts of terminal villi, as well as perivascular fibroblasts and vascular smooth muscle cells of the stem villi. Lower levels of both total GR and phospho-GR were found within cytotrophoblast cells relative to fibroblasts, whereas syncytiotrophoblast showed very little total GR or phospho-GR immunoreactivity. This pattern holds true for immunoblot analysis of extracts from cell fractions cultured ex vivo. In cultured placental fibroblasts, phosphorylation of GR increased upon short-term GC treatment, consistent with a role for GR phosphorylation in receptor transactivation. Total GR levels were reduced by nearly 90% after long-term hormone treatment; however, this down-regulation was independent of changes in GR mRNA levels. These findings demonstrate that GR levels in fibroblasts can be modulated by changes in hormone exposure. Such cell type-specific differences in GR protein expression and phosphorylation may provide the means of differentially regulating the GC response among the cells of the human placenta.

Blotting, Western↗

PubMed2005

Role of insulin/insulin-like growth factor 1 signaling pathway in longevity.

The insulin/insulin-like growth factor 1 (IGF-1) signaling pathway is evolutionary conserved in diverse species including C.elegans, saccharomyces cerevisiae, Drosophila melanogaster, rodents and humans, which is involved in many interrelated functions that are necessary for metabolism, growth and reproduction. Interestingly, more and more research has revealed that insulin/IGF-1 signaling pathway plays a pivotal role in the regulation of longevity. Generally, disruption of the power of this pathway will extend longevity in species ranging from C.elegans to humans. The role of insulin/IGF-1 in longevity is probably related to stress resistance. Although the underlying mechanisms of longevity are not fully understood, the Insulin/IGF-1 signaling pathway has attracted substantial attention and it will be a novel target to prevent or postpone age-related diseases and extend life span. In this review, we mainly focus on the similar constitution and role of insulin/IGF-1 signaling pathway in C.elegans, saccharomyces cerevisiae, rodents and humans.

Animals↗

PubMed2005

Microarray analysis of gene expression involved in anther development in rice (Oryza sativa L.).

In flowering plants, anthers bear male gametophytes whose development is regulated by the elaborate coordination of many genes. In addition, both gibberellic acid (GA3) and jasmonic acid (JA) play important roles in anther development and pollen fertility. To facilitate the analysis of anther development genes and how GA3 and JA regulate anther development, we performed microarray experiments using a 10-K cDNA microarray with probes derived from seedlings, meiotic anthers, mature anthers and GA3- or JA-treated suspension cells of rice. The expression level change of 2155 genes was significantly (by 2-fold or greater) detected in anthers compared with seedlings. Forty-seven genes, representing genes with potential function in cell cycle and cell structure regulation, hormone response, photosynthesis, stress resistance and metabolism, were differentially expressed in meiotic and mature anthers. Moreover, 314 genes responded to either GA3 or JA treatment, and 24 GA3- and 82 JA-responsive genes showed significant changes in expression between meiosis and the mature anther stages. RT-PCR demonstrated that gene y656d05 was not only highly expressed in meiotic anthers but also induced by GA3. Strong RNA signals of y656d05 were detected in pollen mother cells and tapetum in in situ hybridization. Further characterization of these candidate genes can contribute to the understanding of the molecular mechanism of anther development and the involvement of JA and GA3 signals in the control of anther development in rice.

Cells, Cultured↗

PubMed2005

Nitrite-modified extracellular matrix proteins deleteriously affect retinal pigment epithelial cell function and viability: a comparison study with nonenzymatic glycation mechanisms.

PURPOSE: Extracellular matrix (ECM) plays an important role in the regulation of cell function. The aging process may involve chemical modifications to ECM proteins, which may contribute to the aging of the Bruch membrane and pathogenesis of age-related macular degeneration (AMD). The purpose of this study is to investigate nitrite modification of basement membrane-like proteins on RPE cell behavior as a model for the aging of the Bruch membrane in age-related eye diseases. As a comparison, retinal pigment epithelium (RPE) cell behavior on glycolaldehyde-modified matrices (GMM) was also studied. METHODS: Growth factor reduced Matrigel was reacted with nitrite or glycolaldehyde for 1 week or 12 hr, respectively. Calf RPE cells were plated on the modified matrices and examined in several ways. Attachment rates, proliferation rates, apoptosis, and necrosis were determined. Cell morphology and cell susceptibility to A2E-mediated damage was also monitored. RESULTS: Nitrite-modified matrices (NMMs) inhibited cell attachment by 65% and proliferation by 33.7% compared to 69.6% and 21.7%, respectively, by GMM. Proliferation inhibition was not significant when cells were plated at high density on GMM (3.47%) but significant on NMM (20.9%). NMM induced cell apoptosis and necrosis, but GMM induced cell apoptosis only. Both modifications inhibited RPE differentiation. RPE cells on both matrices were more susceptible to blue light mediated damage by A2E, but damage was greater on NMM. CONCLUSIONS: NMM has significant damaging effects on RPE cell function and viability that is similar to the damaging effects of GMM. These studies may have relevance to the RPE dysfunction observed during the progression of AMD.

Animals↗

PubMed2005

KDR and Sema3 genes expression in bone marrow stromal cells and hematopoietic cells from leukemia patients and normal individuals.

Kinase domain receptor (KDR) and Semaphorin3 (Sema3) have a functional relationship and are expressed in human bone marrow (BM). We cultured in vitro bone marrow stromal cells (BMSCs) and collected nonadherent cells from patients with acute myeloid leukemia (AML), chronic myelogenous leukemia (CML), acute lymphoblastic leukemia (ALL) and normal individuals. Reverse transcriptase polymerase chain reaction enzyme-linked immunosorbent assay (RT-PCR-ELISA) was performed to examine KDR and Sema3 genes expression, using beta2 microglobulin as an internal reference. KDR expression ratio in normal control BMSCs (97.0%, 32/33) was higher than in its corresponding nonadherent cells (70.8%, 17/24). KDR expression levels in ALL BMSCs and AML nonadherent cells were significantly higher than in normal controls. Sema3 expression ratios in nonadherent cells from AML (78.6%, 11/14) and CML (71.4%, 10/14) were both significantly lower than in normal control (100%, 27/27), its expression levels were also significantly lower than in normal control. Sema3 expression level in normal BMSCs was significantly lower than in nonadherent cells. Sema3 and KDR genes expression levels displayed a significantly positive correlation in normal control and ALL nonadherent cells (r=0.703, P=0.002; r=0.999, P=0.001). These results suggests that KDR may play a critical role in sustaining the hematopoietic microenvironment due to its high expression, and that KDR may be involved in pathogenesis of AML and ALL. Sema3 could also sustain the survival of hematopoietic cells with its high expression, while Sema3 gene expression may be inhibited in AML and CML.

Adolescent↗

PubMed2005

Microarray analysis of mechanical shear effects on flexor tendon cells.

BACKGROUND: Adhesion formation after flexor tendon repair remains a clinical problem. Early postoperative motion after tendon repair has been demonstrated to reduce adhesion formation while increasing tendon strength. The authors hypothesized that during mobilization, tendon cells experience mechanical shear forces that alter their biology in a fashion that reduces scar formation but also activates key genes involved in tendon healing. METHODS: To test this hypothesis, primary intrinsic tenocyte cultures were established from flexor tendons of 20 Sprague-Dawley rats and sheared at 50 rpm (0.41 Pa) using a cone viscometer for 6 and 12 hours. Total RNA was harvested and compared with time-matched unsheared controls using cDNA microarrays and Northern blot analysis. RESULTS: Microarray analysis demonstrated that mechanical shear stress induced an overall "antifibrotic" expression pattern with decreased transcription of collagen type I and collagen type III. Shear stress down-regulated profibrotic molecules in the platelet-derived growth factor, insulin-like growth factor, and fibroblast growth factor signaling pathways. In addition, shear stress induced an overall decrease in transforming growth factor (TGF)-beta signaling pathway molecules with down-regulation of TGF-beta2, TGF-beta3, TGF-RI, and TGF-RII expression. Moreover, sheared tendon cells increased expression of matrix metalloproteinases and decreased expression of tissue inhibitors of metalloproteinase, an expression pattern consistent with an antifibrotic increase in extracellular matrix degradation. However, the authors also found up-regulation of genes implicated in tendon healing, specifically, vascular endothelial growth factor-A and several bone morphogenetic proteins. Interestingly, the known mechanoresponsive gene, TGF-beta1, also implicated in tendon healing, was differentially up-regulated by shear stress. Northern blot validation of our results for TGF-beta1, TGF-beta2, TGF-beta3, and collagen type I demonstrated direct correlation with the authors' microarray data. CONCLUSIONS: The authors demonstrate an overall antifibrotic expression pattern in response to shear stress in tendon cells that may provide insight into the mechanisms by which early mobilization decreases adhesion formation without impaired tendon healing.

Animals↗

PubMed2005

Rapid alterations in transferrin sialylation during sepsis.

The inflammatory process is associated with alterations in iron metabolism. Transferrin, an acute-phase N-glycosylated glycoprotein, plays an important role in iron transport. Human serum transferrin contains two biantennary glycans, each consisting of 0 to 4 molecules of sialic acid (SA); its SA content is heterogeneous with high concentration of tetrasialotransferrin (4SA) and low amounts of disialo-, trisialo-, penta-, and hexasialotransferrin. The hepatic uptake of iron is greater for desialylated transferrin isoforms (disialotransferrin) than for the other forms. We hypothesized that serum levels of carbohydrate-deficient transferrin (CDT, disialotransferrin) may increase rapidly in septic patients. Blood samples were obtained from critically ill patients with (n = 15) and without (n = 14) documented sepsis and compared with healthy volunteers. The different forms of transferrin were studied by capillary zone electrophoresis; SA concentrations were measured by enzymatic colorimetric assay. There was a significant increase in the proportion of CDT in septic compared with nonseptic patients and volunteers (18.3% [1.3-30.5] vs. 0.7% [0.5-0.9]; P < 0.01 and 0.9% [0.5-1.1]; P < 0.05). Conversely, tri- and tetrasialotransferrin levels were lower in septic patients. Total and free SA concentrations were significantly higher in septic patients than in healthy volunteers. In a sheep model of septic shock secondary to peritonitis, serum free SA was already increased after 15 h. Sepsis is associated with decreased SA content on circulating transferrin and with an increase in blood free SA concentrations. In view of these rapid modifications and the long half-life of transferrin, the most likely explanation is degradation of transferrin by neuraminidase. Further studies including measurement of blood neuraminidase concentration and activity are needed to understand the process and exact role of SA decrease in septic patients.

Acute Disease↗

PubMed2005

Crohn's disease in mainland China: a systematic analysis of 50 years of research.

BACKGROUND: Crohn's disease appears to be increasing in frequency in many areas of the world. However, little information with regard to disease incidence, prevalence and temporal trends has been published in China. OBJECTIVE: The aim of this review is to better understand the occurrence of Crohn's disease in mainland China, and to give an overview of the current status of the disease. METHODS: We used a computer-based literature search using 50-years of records from the Chinese Database of Biology and Medicine (CBM, 1979-2002), combined with a manual year-by-year search of the literature from 1950 to 1979. Each article was double-reviewed, and all descriptive epidemiological data were recorded, pooled and statistically analyzed. RESULTS: In total, 1526 cases of Crohn's disease since 1950 have been reported by more than 50 hospitals from 22 provinces and cities in mainland China, comprising 884 male and 642 female patients, with a 1.38:1 male predominance. More than 70% of patients were aged 20 to 50 years old, with a mean age of 37.2 +/- 2.68 (ranging from 1 to 83) years. The extrapolated disease incidence and prevalence rates are 0.28/100,000 person years and 1.38/100,000 persons, respectively. CONCLUSIONS: The incidence and prevalence rates of Crohn's disease are still lower than those in Western and other Asian countries, but these rates have been increasing rapidly, and the disease is no longer uncommon. An underestimation may occur because the patients who were misdiagnosed or did not seek medical advice could not be included in the study. A future population-based survey is warranted.

Adolescent↗

PubMed2005

Childhood physical and sexual abuse in China.

In order to determine the prevalence and characteristics of childhood physical and sexual abuse in China, the authors conducted a survey in Shanghai. The Dissociative Disorders Interview Schedule was administered to 423 inpatients and 304 outpatients at Shanghai Mental Health Center, and to a non-clinical sample of 618 workers at a clothing factory. The results were compared to a previous sample of 502 respondents in the general population in Winnipeg, Canada. The identities of the perpetrators of physical and sexual abuse, and the types of sexual abuse reported were similar in the two countries; however, the rates of reported abuse were lower in China. Childhood sexual abuse appears to be far less common in the general population in Canada than in China.

Adult↗

PubMed2005

[Expressions of transcription factor GATA-1 and GATA-2 genes in bone marrow stromal cells from patients with leukemia].

In order to investigate expressions of transcription factor GATA-1 and GATA-2 genes in the bone marrow stromal cells (BMSCs) from patients with leukemia or normal controls, bone marrow stromal cells from 34 normal cases and 42 cases with leukemia were cultured long-term in vitro. Nonadherent cells (bone marrow hematopoietic cells) and amplified adherent cells (BMSC) were collected separately. Expressions of GATA-1 and GATA-2 genes were analyzed by using RT-PCR-ELISA; the semi-quantitative expression levels of GATA genes in the BMSCs from patients with leukemia were compared with normal controls. The results showed that expressions of GATA-1 and GATA-2 genes could be detected in the BMSCs and the bone marrow hematopoietic cells from both normal controls and the cases of leukemia. The expression ratio of GATA-1 in the BMSCs from acute lymphocytic leukemia (ALL) (85.7%) was similar to the normal controls (88.2%), whereas the expression ratios in BMSCs from acute myelocytic leukemia (AML) (55.6%) and chronic myelocytic leukemia (CML) (41.2%) were significant lower than the normal controls (P < 0.05). The rank of expression level of GATA-1 gene in the BMSCs was "ALL>AML>normal>CML". There was no difference in the expression level of GATA-2 gene within the BMSCs from normal controls and patients with leukemia. The ranks of expression levels of GATA-1 and GATA-2 genes in bone marrow hematopoietic cells were "AML>normal>ALL>CML" and "AML>CML>ALL>normal". The dominant expression of GATA-2 gene was found in the BMSCs from AML, CML or normal controls. It is inferred that the expressions of GATA-1 and GATA-2 genes in the BMSCs of normal controls and patients with leukemia may influence the regulation of hematopoiesis in the bone marrow stroma and it is worthy of further study to explore their roles in pathogenesis and development of leukemia.

Adolescent↗

PubMed2005

An effective approach to assay plant response to environmental factors--DNA microarray.

With huge plant DNA data released by genome sequence project, the high-throughput DNA microarray technology has been proven an effective way to bridge the gap between plant genome sequence information and functional genomics. The technology has been used to investigate the gene expression patterns and to elucidate the role of genes. In this review, we briefly outline the features of DNA microarray and highlight its recent applications in plant biology, especially in the identification of stress-response elements and in the clarification of plant signal network.

Disasters↗

PubMed2005

[Differential effect of temperature on Plt and PCA synthesis in a rsmA inactivated mutant strain of Pseudomonas sp. M-18].

Rsm (repressor of secondary metabolite) A is an mRNA binding protein which functions as a global repressor to control multiple genes at the posttranscriptional level. Using homologous recombination technique a chromosomal rsmA inactivated mutant strain M-18R was constructed in Pseudomonas sp. M-18, a strain of plant-growth-promoting rhizobacteria, which could inhibit several soilborn phytopathogens by producing secondary metabolites including phenazine-1-carboxylic acid (PCA) and pyoluteorin (Plt) in one single strain. To further study the effect of RsmA on the synthesis of Plt and PCA in the wild type strain M-18, the dynamic curves of Plt and PCA produced respectively by M-18 and M-18R were measured in KMB medium under different temperature conditions such as 37 degrees C constant, 28 degrees C constant and nonconstant (37 degrees C 4 hours at first and then 28 degrees C constant) cultivation. The synthesis of both Plt and PCA were almost inhibited in the cultures under the condition of 37 degrees C. At 28 degrees C, however, compared with the wild type strain M-18, the mutant strain produced tenfold amount of Plt, while the production of PCA decreased only about 50%. When cultivated under the nonconstant condition, the amount of Plt produced by M-18R could reach 400 microg/mL while the PCA production was not significantly affected, but in the wild type strain M-18, the amount of Plt production decreased obviously while the PCA production was not affected in comparison with the results at 28 degrees C constant. These results suggest that a temperature sensitive factor exists to function as an activator independent of RsmA to promote the synthesis of Plt in the rsmA mutant strain M-18R while it may bind with RsmA to repress the synthesis of Plt in the wild type strain M-18. But this factor did not exert any affect on the synthesis of PCA.

Bacterial Proteins↗