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Biomedical subjects

Yi Zhang

Publications and source records attributed to Yi Zhang.

At least 253 records · Page 14Linked to original sources
PubMed2005

[A study on risk of malignant neoplasm and environmental exposure to crocidolite].

OBJECTIVE: To explore the risk of developing malignant neoplasm in a cohort with the history of environmental exposure to crocidolite asbestos. METHODS: A retrospective cohort and follow-up study covering 15 years (1987 --> 1995 --> 2001) was carrid out in a small town in Yunnan province. The cohort comprised 6254 local inhabitants. The deaths from and the RR of asbestos-related malignant neoplasms were studied. RESULTS: There were 186 deaths from neoplasms in the observation group, the mortality being 2160.5 per 10(6) person-years (RR=1.293, 95%CI: 1.032-1.618), 20 of those deaths were caused by mesothelioma, with a crude mortality of 232.3 per 10(6) person-years (RR=17.929; 95%CI: 2.406-133.592). The mortalities for men and women were 267.5 and 186.7 per 10(6) person-years respectively. The crude mortality from lung cancer (56 deaths) was 650.5 per 10(6) person-years,there is no significance between the two groups (RR=1.434; 95%CI: 0.968-2.486). The difference in mortality from gastrointestinal cancer between the two groups is not significant, whereas the risk of man intestinal cancer in the observation is significant (RR=3.71; 95%CI: 1.077-13.270). CONCLUSION: The risk of developing mesothelioma is significantly increased in the population with environmental exposure to crocidolite. The risk of man intestinal cancer in the town awaits additional studies.

Adult↗
PubMed2005

[Osteoblasts derived from mesenchymal stem cells harbor immunoregulatory effect].

In an attempt to study the immunoregulatory effect of osteoblasts derived from mesenchymal stem cells (MSC), MSC was induced to differentiate into osteoblasts for one week. The growth pattern and the phenotype were evaluated by MTT and flow cytometry respectively. The immunoregulatory effect was tested by the inhibitory effect on T cell proliferation. The result showed that during the differentiation cells grew fast and there was no significant change in the phenotypes but keeping CD73, CD105, CD44, CD29 positive and CD34, CD45, HLA-DR, CD86 negative. Osteocyte derived from MSC also showed immunosuppressive effect on T cell proliferation in adose-dependent manner. It is concluded that osteoblasts derived from MSC also harbored immunoregulatory effect.

Bone Marrow Cells↗
PubMed2005

[Observation on the biological behavior of human umbilical cord blood adherent cells].

To study the possibility of separation and culture of human umbilical cord blood adherent cell (HUCBAC), the umbilical cord blood CD34(+) cells were cultured in Dexter system in order to evaluate and observe the biological behavior of adherent cells in vitro. The results showed that all cells were cultured with Dexter system. By day 9-14 (at a median of 11.2 days), adherent cell colonies formed and reached their maximum at 15-22 days (mean 19.6 days), by day 28, all adherent cells spread over the bottom of Petri dish. By means of light microscopy, these cells were found to differentiate into three kinds of cells in culture of 28 days: fibroblast-liked cell, macrophage liked cell and small-round cells. The ratio of these three kinds of cells was 56.8%, 38%, 5.5% respectively. Cytochemistry assay revealed that the positive rate reached 100% in NSE stain and PAS stain; the adherent cell by ALP stain were shown 35% positive, but in POX stain the result was negative. Immunohistochemistry stain revealed that the positive rate of cord adherent cells for CD106, CD29, CD44, CD45, CD50, Fn, Ln, collagen IV etc reached 96%, 93%, 98%, 68%, 72%, 92%, 74%, 83% respectively. It is concluded there are hematopoietic adherent precursors in cord blood CD34(+) cells and the HUCBAC shows some biological behavior of hematopoietic stromal cells.

Antigens, CD34↗
PubMed2005

[Dynamic alteration of blood lipid and hemodynamics parameters and vascular intima in the process of atherosclerosis].

To establish and observe rabbit hyperlipemia and atherosclerosis model, we combined the method of high-lipid diet and immuoreactive injure. We divided 45 New Zealand rabbit into control group and high-lipid group. According to the time (4, 8, 12 weeks) of established model, the control group and high-lipid group were divided into 3 groups respectively. The blood-lipid, the hemodynamics parameter and vascular intima were determined and observed. The results showed: (1) After feeding 4, 8, 12 weeks, TC and LDL-C of the high-lipid group in the serum increased obviously. After feeding 8 week, TG of the high-lipid group began to increase obviously. HDL-C of the high-lipid group was higher than control group, but with a descendent trend. (2) Blood viscosity of the high-lipid group increased obviously under the 0.512 S(-1) and 5.96 S(-1) at 12 week. Blood flow increased obviously at 8 and 12 week. SBP increased evidently at 8 and 12 week. Alteration of the plasma viscosity and vascular diameter were not obvious. (3) By observing with optical microscope the intima of the control group is smooth. The intima of the high-lipid group has a light incrassation at 4 week. The intima of the high-lipid group has a obvious incrassation at 8 and 12 week. By observing with through transmission electron microscopy (TEM), the lipid vacuole is under the endothelium cell. (4) By adopting the immunohistochemistry, the foam cell that derived from smooth muscle cell were determined. We concluded that the blood lipid can have a prefigurative role in atherosclerosis; blood flow and blood pressure and blood viscosity increase at low shear rate in the course of the atherosclerosis; vascular intima is incrassate and the composition of the AS plaque is variational continually.

Animals↗
PubMed2005

[uPA expression of gastric cancer cell lines and its correlation with peritoneal seeding].

OBJECTIVE: To study the correlation between expression of urokinase-type plasminogen activator (uPA) and capability of tumor cell seeding to the peritoneal membrane by different gastric cancer lines. METHODS: Expression of uPA in 4 human gastric cancer cell lines was examined by semi-quantitative RT-PCR, ELISA and Western blot. uPA activity was determined by an assay kit. After ip inoculation of cancer cells to nude mice, tumors on peritoneal membrane was grossly examined for tumor cell seedings. RESULTS: SGC7901 was the highest in uPA expression among human gastric cancer cell lines AGS, SGC7901, MKN45, and MKN28. MKN45 had the strongest uPA activity, while AGS was lowest in both uPA expression and activity. Peritoneal seeding tumors of various sizes were observed in mice inoculated with SGC7901 and MKN45 cells. In addition to peritoneal seedings, bloody ascites was present in mice inoculated with MKN28. The MKN45-inoculated mice took the least time to develop tumors and had the shortest surviving period. No peritoneal seeding was seen in mice inoculated with AGS cells. CONCLUSION: Three of 4 human gastric cancer cell lines studied express uPA mRNA and activity, which correlate with their peritoneal seeding potentials.

Adenocarcinoma↗
PubMed2005

[Effects of seeding and sowing methods on the yields of root tubers of Curcuma longa].

OBJECTIVE: To provide a scientific basis for standardizing the cultivation method for Curcuma longa. METHOD: Plant heights and seeding numbers were sampled periodically, the plot yields were counted a tharvested. RESULT: The effects of seeding method on yields, plant height and number were significant. The effects of different sowing ways on the yields were very little. CONCLUSION: The hole seeding method using mother tuber or blastostyle bearing three to four knots was shown to be the best may, worthy to be widely applied in production.

Curcuma↗
PubMed2005

[Clinical application of a modified posterior vaginal wall hammock in female pelvic floor reconstruction].

OBJECTIVE: To explore the feasibility and effectiveness of a modified posterior vaginal wall hammock (PVWH) in the treatment of female pelvic organ prolapse without removal of uterus. METHODS: Thirty-two patients with different defects of pelvic organ prolapse underwent a modified PVWH. The procedures included restoring the position of prolapsed uterus by suturing polypropylene mesh to bilateral sacro-spinous ligaments, strengthening utero-sacral ligament by intra-vaginal slingplasty (Tyco Healthcare Group), forming a new recto-vaginal fascia and strengthening levator ani muscle. RESULTS: The average operating time was 55 minutes and hemorrhage was 150 ml respectively. Recovery of uterine prolapse was achieved in all cases. After an average follow up of seven months, no vagina distortion, shortening and dyspareunia were observed. One patient had uterine cervix elongation three months after operation. The relieving rate of subjective symptoms was more than 50%. CONCLUSIONS: Female uterine prolapse could be cured by the modified PVWH and the uterus could be successfully reserved during pelvic floor reconstruction with promising short-term results. More clinical trials are needed to evaluate its effectiveness, safety and long-term outcome.

Adult↗
PubMed2005

[A revised scheme for LeFort classification of upper jaw fractures].

OBJECTIVE: To put forward a revised scheme on LeFort classification for the upper jaw fractures. METHODS: 193 consecutive cases with the primary diagnoses of upper jaw fractures were involved in this study, for each one of which water's and CT scan were available to decide the fracture site and pattern. Data were filed in term of classification items as LeFort I, II and III fracture, as well as sagittal fracture and alveolar fracture. Statistical analysis was done to validate the meliorating thought on and revised scheme on LeFort classification. RESULTS: It was validated that of 185 cases with upper jaw fractures only 30.81% which presented single-line fracture and 34.06% which presented multiple-line fracture were covered with LeFort classification. Additional 13.51% with single-line fracture and 21.61% with multiple-line fracture could be included when LeFort classification was extended with increase of items of sagittal fracture and alveolar fracture. Further results revealed that among total 344 sites or fracture lines included in 193 cases, 81.10% could be diagnosed fracture pattern of LeFort classification. Of 65 fracture sites presenting LeFort III type, 92.31% were concomitant with LeFort II type or LeFort I and II type, very few being alone. CONCLUSIONS: A revised classification was proposeded that upper jaw fractures could be classified into four types as follows: (1) high horizontal fracture (corresponding to LeFort II and III type), (2) low horizontal fracture (corresponding to LeFort I type), (3) sagittal fracture (including midline and para-midline fracture) and (4) alveolar fracture.

Adolescent↗
PubMed2005

[Influence of anti-CXCR4 monoclonal antibody 12G5 on killing effect of cytosine arabinoside to HL-60 cell].

This study was aimed to explore the influence of anti-CXCR4 monoclonal antibody 12G5 on killing effect of cytosine arabinoside (Ara C) to HL-60 cell, and to assess its therapeutic value in marrow residual disease. HL-60 cells were cultured and co-cultured with leukemic stromal cells, and SDF-1 activity was inhibited with 10 microg/ml 12G5, then, killing effects of Ara C on HL-60 cells were investigated by MTT and morphology assay. Curves by MTT assay revealed that in the test group of 20 microg/ml Ara C, A(540) values decreased slowly but straightly, however, in control group A(540) values decreased markedly for the first two days, and increased from day 3 or 4. In the test group of 40 microg/ml Ara C, although increasing at constricted range of 7 - 9 days, A(540) values decreased in whole observing period of 12 days, while in control group A(540) values decreased markedly at day 0-3, and increased from day 4. Furthermore, two curves go across each other at day 5, and continue the increasing tendency. Morphology results showed that in both treated groups, the number of HL-60 cell decreased markedly and increased gradually in control group, but just contrary to test group. It is concluded that 12G5 may weaken the killing effect of Ara C on HL60 cell in earlier period, but reinforce the total killing effect and delay the occurrence of drug resistance simultaneously. Thus 12G5 has the therapeutic potential on marrow residual disease.

Antibodies, Monoclonal↗
PubMed2005

[Electrochemical reduction of nitrobenzene under mild conditions].

Effect of cathode materials (S1, S2, AB5, graphite, Ni plate, Fe plate) on the electrochemical reduction of nitrobenzene of light concentration under mild conditions(current density less than 1.0 mA/cm2, pH in the range of 4 - 9), was experimentally studied. In aqueous solution, S1, S2 and AB5 electrodes showed high selectivity of nitrobenzene reduction to aniline, with the nitrobenzene conversion and aniline yield being over 85% and 75%, respectively. The results obtained by cyclic voltammograms and single sweep voltammograms showed that nitrobenzene was directly reduced at S1 and S2 electrodes, while reduced by hydrogen at AB5 electrode. The products electroreduced from nitrobenzene on S1, S2 and AB5 cathodes could be easily degraded by aniline degrading strain AN3 under aerobic condition.

Electrochemistry↗
PubMed2005

[Effect of ERK1/2 on low shear stress-induced expression of IL-8 mRNA in human endothelial cells].

Fluid shear stress plays an important role in many physiological and pathophysiological processes of the cardiovascular system. It modulates vascular function and structure via stimulating mechanosensitive endothelial cell signal events. Previous studies have identified that the exposure of vascular endothelial cells to fluid mechanical forces can modulate the expressions of many genes, including IL-8 gene. In order to gain an insight into the role of extracellular signal regulated kinase (ERK1/2) signal pathway in the expression of IL-8 mRNA in human umbilical vein endothelial cells (HUVECs) under the stimulation by low shear stress (4.20 dyne/cm2), we employed Western blot to measure phosphorylation of ERK1/2 and used quantitative reversal transcription-polymerase chain reaction (qRT-PCR) to assay the expression of IL-8 mRNA. The results showed: (1) Shear stress could activate ERK1/2 with a rapid, biphasic time course (maximum by 10 min and basal by 2 h); the treatment of HUVECs with Genistein (a highly specific inhibitor of tyrosine protein kinase, TPK) or PD98059 (the inhibitor of mitogen-activated protein/extracellular signal regulated kinase kinase, MEK) culd prevent shear-dependent activation of ERK1/2; (2) When treated with Genistein or PD98059, significant inhibition of IL-8 mRNA expression induced by low shear stress was observed in HUVECs. This in vitro study demonstrates that ERK1/2 plays an important role in IL-8 mRNA expression induced by low shear stress.

Cells, Cultured↗
PubMed2005

[Expression of bcl-2 and bax protein in uterine leiomyosarcomas and leiomyomas].

OBJECTIVE: To determine the expression and significance of the apoptosis regulatory protein bcl-2 and bax in uterine leiomyosarcomas and uterine leiomyomas. METHODS: The expression of bcl-2 and bax were examined by immunohistochemical ABC staining with specific antibodies in 34 cases of uterine leiomyosarcomas (18 cases in stage I , 1 in stage II , 8 in stage III, and 7 in stage IV ), 34 uterine leiomyomas and 34 normal myometrium samples. RESULTS: Bcl-2 expression was higher in uterine leiomyomas than that in normal myometrium and in uterine leiomyosarcoma (P < 0.01 ); bcl-2 expression in uterine leiomyosarcoma was higher than that in normal myometrium (P < 0.05). Bax expression in normal myometrium was higher than that in leiomyomas and in uterine leiomyosarcoma (P < 0.01). There was no obvious difference in bax expression between leiomyomas and leiomyosarcoma (P > 0.05). Both the expressions of bcl-2 and bax proteins in stage I - II were higher than those of in stage III - IV (P < 0.01). The bcl-2 positive leiomyosarcoma has a favorable clinical outcome than that of bcl-2 negative. CONCLUSION: The imbalance between the expression of bcl-2 and bax may play a certain role in the genesis of the uterine leiomyomas and leiomyosarcomas. Bcl-2 and bax may be involved in the early stage of the tumor genesis of uterine leiomyosarcoma. Bcl-2 might correlate with the prognosis of the uterine leiomyosarcoma.

Adolescent↗
PubMed2005

Preconditioning effects on expression of proto-oncogenes c-fos and c-jun after hepatic ischemia/reperfusion in rats.

BACKGROUND: Ischemia/reperfusion is the main cause of hepatic damage in liver transplantation. Immediate early genes (IEGs) encode proteins can regulate expression of cellular response genes after injury, and is associated with tissue repair and cell apoptosis. The purpose of this research was to investigate the effects of preconditioning on expression of immediate early genes c-fos and c-jun following hepatic ischemia/reperfusion (IR) and its roles in cellular regeneration and apoptosis. METHODS: Ninety-six Wistar rats were randomly divided into IR group and hepatic ischemic preconditioning (IPC) group, and each group was further divided into eight sub-groups (n=6). The model of partial liver ischemia/reperfusion was used. The rats were subjected to 60-minute liver ischemia, preceded by 10-minute preconditioning. After 0-, 0.5-, 1-, 2-, 4-, 8-, 12-, 24-hour reperfusion, the serum and liver tissue in each group were collected to detect the level of serum ALT/AST, liver histopathology, expression of c-fos, and c-jun mRNA. Flow cytometer was used to detect Ki67 and Sub-G1 as the quantity indicators of cell regeneration and apoptosis respectively. RESULTS: Compared with IR group, IPC group showed a significantly lower ALT/AST level in 0.5-hour sub-group to 8-hour sub-group (P<0.05). Ki67 elevated significantly at 0.5, 1, 2 hours, but decreased significantly at 24 hours (P<0.05). Ap index decreased significantly after 1-hour reperfusion (P<0.05). Expressions of c-fos and c-jun mRNA were low, especially c-jun at 0.5, 1 and 2 hours after reperfusion. CONCLUSION: Ischemic preconditioning can protect liver cells against ischemia/reperfusion injury, and this protective effect may be related to influence transcription levels of c-fos and c-jun.

Animals↗
PubMed2005

Panax notoginseng saponins preconditioning protects rat liver grafts from ischemia/reperfusion injury via an antiapoptotic pathway.

BACKGROUND: Ischemia/reperfusion (I/R) injury is a major cause of primary graft dysfunction and renders an allograft more immunogenic in orthotopic liver transplantation (OLT). Panax notoginseng saponins (PNS) has been reported to exert protective effects against I/R injury to various organs. The objective of this study is to investigate whether PNS preconditioning protects rat liver grafts from I/R injury via an antiapoptotic pathway. METHODS: Male Sprague-Dawley rats were used as donors and recipients of orthotopic liver transplantation (OLT) and were divided into PNS preconditioning group(group P) and normal saline control group (group N) randomly according to whether PNS (50 mg/kg) was injected intravenously 1 hour before liver grafts harvesting, and sham group (group S). The animals were separately killed 2, 6 and 24 hours after reperfusion. Plasma samples were collected for test of alanine aminotransferase (ALT) and aspartate aminotransferase (AST). Liver tissues were collected to detect histological changes, apoptosis and the expression of TNF-alpha, Bcl-2 and Caspase-3 mRNA. RESULTS: The serum levels of ALT and AST and the apoptosis index (AI) of liver tissue in group P were lower than in group N significantly 2, 6 and 24 hours after reperfusion. Compared with group N, the expression of TNF-alpha and Caspase-3 mRNA was reduced significantly in group P 2 and 6 hours after reperfusion and the expression of Bcl-2 mRNA was enhanced significantly in group P 6 and 24 hours after reperfusion. CONCLUSIONS: PNS preconditioning protects liver grafts from I/R injury effectively in rat OLT via an antiapoptotic pathway. The antiapoptotic mechanisms of PNS may include inhibiting the expression of TNF-alpha and Caspase-3 and enhancing the expression of Bcl-2.

Analysis of Variance↗
PubMed2005

[Surgical management for pulmonary metastasis].

OBJECTIVE: To investigate the indications of resection for lung metastasis, the surgical procedure and factors affecting the survival based on our experience accumulated for 37 years. METHODS: A total of 108 patients with pulmonary metastasis was treated by surgery. Pathology showed 93 carcinoma (86.1%) and 15 (13.9%) sarcoma. Totally 122 operations were performed: partial lung resection 51, segmental lobectomy 7, lobectomy 40, pneumonectomy 15. RESULTS: After surgery, the cumulative 1-, 3-, 5-, 7- and 10-year post-thoracotomy survivals were 87.9%, 47.3%, 31.7%, 23.7% and 13.9%, with an overall median survival of 34.8 months. Solitary lesions, disease-free interval (DFI) > 36 months, absence of extrathoracic disease and "open" thoracotomy were predictors of a longer survival whereas age, gender, symptom and pathology of the primary tumor were found statistically insignificant prognostic factors. CONCLUSION: Surgery should be undertaken for patients who do fulfill these criteria, and "open" thoracotomy is a better choice. Surgical treatment for patients with short DFI and multiple lesions should be attempted with prudence.

Adolescent↗
PubMed2005

[The function of ERK on Fas-mediated apoptotic signaling pathway of human gastric carcinoma cells].

OBJECTIVE: To analyze the expression and functions of ERK (extracellular regulated kinase) in Fas-mediated apoptosis in gastric carcinoma cell line SGC-7901 and to elucidate the potential significance of this signaling pathway in tumor progression. METHODS: Radioisotope labeling and Western blotting with special anti-ERK antibody were used to check ERK activity in SGC-7901 cell line after anti-Fas antibody treatment. Apoptosis induced by several treatment factors was evaluated by FACS can flow cytometer. RESULTS: ERK activity increased and reached the peak at 30 min after treatment with anti-Fas antibody and decreased in PD98059 pretreated group. The number of sub-G(1) cell was 30.5% +/- 2.6% in PD98059 pretreated group, which was higher than anti-Fas treatment group and control group, respectively. CONCLUSION: In gastric cancer cell line SGC-7901, Fas-induced ERK activation may suppress Fas-mediated apoptosis. Inhibition of ERK may enhance the sensitivity of SGC-7901 cells to Fas-mediated apoptosis. Fas-induced ERK activation may confer gastric cancer cells ability to escape the immune surveillance.

Apoptosis↗
PubMed2005

[Cleavage of telomerase RNA component by two DNAzymes and their effects on expression of two apoptosis-related genes in human mammary cancer cells].

OBJECTIVE: To investigate the cleavage of telomerase RNA component (hTR) by two DNAzymes and their effects on the expression of two apoptosis-related genes in a human mammary cancer cell line (MCF-7). METHODS: Two "10-23" DNAzymes (DzT and DzTi) targeted against hTR RNA and their analogues (DzT' and DzTi') were synthesized and used to cleave hTR RNA in vitro and in MCF-7 cells. Reverse transcriptional (RT) PCR amplification of a hTR DNA fragment and telomerase activity assay by PCR-enzyme-linked immunosorbent assay (ELISA) were performed to assess the cleavage efficiency. The biological effect of the DNAzymes was evaluated by measuring the expression of two apoptosis-related genes (bax-2 and bax). RESULTS: The unmodified DNAzyme, DzT, and its modified form, DzTi, which had an 3'-inverted thymidine added, could effectively cleave hTR mRNA in vitro. After transfection into MCF-7 cells, DzTi exhibited more powerful cleavage ability than DzT, and down-regulated the activity of telomerase (P<0.05). However, neither DzTi nor DzT displayed significant effect on the growth of the cells (P>0.05) and the expression of bax-2 and bax (P>0.05). DzT' and DzTi', derived from DzT and DzTi respectively with a base displacement in the conserved catalytic motif, did not exhibit notable cleavage effect on hTR RNA either in vitro or in the cells. CONCLUSIONS: The synthesized DNAzymes can effectively and specifically cleave hTR RNA and decrease the telomerase activity. As a newly found catalytic nucleic acid, DNAzymes will play an important role in gene therapy studies of tumors.

Apoptosis↗