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Biomedical subjects

Wei Chen

Publications and source records attributed to Wei Chen.

At least 361 records · Page 20Linked to original sources
PubMed2004

Resistance of ovarian carcinoma cells to docetaxel is XIAP dependent and reversible by phenoxodiol.

Although several pathways have been proposed to explain chemoresistance, all lead to some specific defect in the mechanism of apoptosis. The objective of this study was to characterize the molecular mechanisms of drug resistance to docetaxel in epithelial ovarian cancer cells (EOC) and the use of phenoxodiol as a chemosensitizer. Four established and 12 primary cultures of ovarian carcinoma cell lines (EOC) were treated with docetaxel (5-500 ng/ml) for 24 and/or 48 h. In all the studied cell lines, the best response was seen using 500 ng/ml of docetaxel. Sensitive cell lines were identified as those with IC50 < 100 ng/ml for 48 h while resistant cell lines were identified as those with IC50 > 100 ng/ml. The morphological features of apoptosis and the activation of caspases were seen only in the sensitive cell lines determined by Hoechst staining and Caspase Glo assay. Although X-linked inhibitor of apoptosis protein (XIAP) was expressed in all EOC cells, it was only inactivated in chemosensitive cells. We confirmed the role of XIAP in docetaxel resistance by downregulation of XIAP expression using RNA interference (RNAi) as well as by pretreatment with phenoxodiol. Our results indicate that 1) docetaxel induces its cytotoxic effect through the activation of apoptosis; 2) caspase activation relies on the removal of XIAP; and 3) phenoxodiol restores sensitivity in docetaxel-resistant EOC cells. We demonstrate that phenoxodiol, by interfering with XIAP activity, functions as a chemosensitizer to docetaxel and could provide a more effective treatment for refractory ovarian cancer.

Antineoplastic Agents, Phytogenic↗
PubMed2004

[Effects of acute hypoxia and intermittent hypoxic acclimatization on erythropoietin and hypoxia-inducible factor-1alpha gene expression in rat hepatic and renal tissues].

OBJECTIVE: To explore the effects of acute hypoxia and intermittent hypoxic acclimatization on gene expression of erythropoietin (EPO) and hypoxia-inducible factor-1alpha (HIF-1alpha) in rat hepatic and renal tissues. METHODS: Twenty-four rats (weight was 180 to 220 g) were divided into three groups: normal control group (NC), intermittent hypoxic acclimatization (IH) and acute hypoxia groups (AH). Gene expression of EPO and HIF-1alpha were examined with Northern dot blot method. RESULTS: As compared with NC group, the levels of EPO gene expression in rat hepatic and renal tissues in AH group were both significantly elevated (P<0.05 or P<0.01). In IH group, the contents of EPO mRNA in hepatic and renal tissues were apparently decreased versus AH group (P<0.01), whilst were not differently elevated in comparison with group NC (P>0.05). In hepatic tissue from AH group, the content of HIF-1alpha mRNA were more than those in NC group and IH group, while the levels of gene expression of HIF-1alpha were no substantial change in renal tissues from different groups (all P>0.05). CONCLUSION: Hypoxic acclimatization can inhibit the increment of EPO gene expression induced by acute hypoxia in rat hepatic and renal tissues, in which HIF-1alpha may play important roles.

Adaptation, Physiological↗
PubMed2004

[Effects of fibroblast growth factor-10 on the secretions of transforming growth factor-alpha, platelet-derived growth factor-AB and vascular endothelial growth factor by normal adult human keratinocytes in culture].

OBJECTIVE: To evaluate the effect of fibroblast growth factor-10 (FGF-10) on the secretion of transforming growth factor-alpha (TGF-alpha), platelet-derived growth factor-AB (PDGF-AB) and vascular endothelial growth factor (VEGF) by human keratinocytes. METHODS: Concentrations of FGF-10 used were 4, 16, 125 and 500 ng/ml. Serum-free keratinocyte growth medium without EGF or with EGF were as negative control and positive control, respectively. Cells were cultured at 2500, 37500 cells/cm 2 in dishes in serum-free medium and supernatants were collected at 24, 48 and 72 hours. The concentrations of TGF-alpha PDGF-AB and VEGF in cell culture supernatant were measured by using TGF-alpha, PDGF-AB and VEGF enzyme linked immunoadsorbent assay (ELISA) kits, respectively and cell numbers were counted by haemocytometer. RESULTS: For cells cultured at low density and cells were subconfluent, TGF-alpha in each group was low and there was no significant difference among them at 24 hours. At 48 hours, both in absolute concentrations and on a per-cell basis, FGF-10 enhanced the secretion of TGF-alpha by cells cultured at low density in a dose-dependent fashion. At 72 hours, the concentrations of TGF-alpha in all dose of FGF-10 were significantly higher than that in negative control (P<0.05). The production of TGF-alpha in pg/10(6) cells in 500 ng/ml FGF-10 reached statistical significance compared with negative control (P<0.05). The secretion of TGF-alpha in FGF-10 were lower than that in positive control at 48 and 72 hours. For cells cuttured at 37500 cells/cm(2), the secretion of TGF-alpha stimulated by FGF-10 was similar to that when cells cuttured at lower density. PDGF-AB in each group was undetectable. When cells cuttured at high density and reached 100 percent confluent, PDGF-AB could not be detected at 24 hours. At 48 hours, both in absolute concentrations and on a per-cell basis, PDGF-AB productions in 125 and 500 ng/ml of FGF-10 were markedly greater than those of negative control at 48 and 72 hours (P<0.05), and the secretion of PDGF-AB stimulated by FGF-10 was in a dose-dependent fashion. For cells cultured at low density, although the concentrations of VEGF in 16-500 ng/ml of FGF-10 were significantly higher than that in negative control (P<0.05) at 72 hours, on a per-cell basis, they were not greater than that of negative control. The secretion of VEGF in positive control was greater than that of FGF-10 at 24-72 hours. CONCLUSION: The effect of FGF-10 on increasing secretion of TGF-alpha and PDGF-AB might mediate the actions of FGF-10 on keratinocytes, fibroblasts and endothelial cells to promote re-epithelialization as well as granulation tissue deposition during wound healing.

Cells, Cultured↗
PubMed2004

[Effects of acidi fibroblast growth factor on hepatic and renal functions after intestinal ischemia/reperfusion injury].

OBJECTIVE: To investigate the change in hepatic and renal functions parameters after intestinal ischemia-reperfusion (I/R) injury, and to explore the effects of acidic fibroblast growth factor (aFGF) on hepatic and renal functions after intestinal I/R injury in rats. METHODS: Seventy-eight Wistar rats were divided into four groups, which are sham-operated (C) group, ischemia (45 minutes) plus reperfusion (R), reconstructive human aFGF treatment (rhF), and wild type aFGF treatment (wtF) groups. The animals were sacrificed at 2, 6, 12 and 24 hours, respectively. Hepatic and renal functions were analyzed. RESULTS: In comparison with those in group C, the hepatic and renal functions were damaged in group R, rhF and wtF decreased. Treatment with rhF and wtF markedly abated the hepatic and renal dysfunction. The desquamation of intestine villi and infiltration of inflammation cells in the submucosa were observed in all groups. CONCLUSION: Hepatic and renal functions are damaged after intestinal I/R injury. Treatment with rhF and wtF could protect against multiple organ dysfunction associated with intestinal ischemia-reperfusiun injury.

Animals↗
PubMed2004

[Gene expression of angiogenesis-related factors in fetal skin at different developmental stages and childhood skin].

OBJECTIVE: To explore the change in gene expression of angiogenesis-related factors vascular endothelial growth factor (VEGF), angiopoietin-1 (Ang-1), acid fibroblast growth factor (aFGF) and basic fibroblast growth factor (bFGF), in fetal skin at different developmental stages and children skin and their potential biological significances. METHODS: Fetal skin samples of human embryo were obtained from spontaneous abortion at different gestational ages ranging from 13 to 32 weeks, and children skin specimens were collected from child patients (4-12 years) undergoing plastic surgery. After morphological characteristics of skin at different developmental stages were defined histologically gene expressions of VEGF, Ang-1, aFGF and bFGF were examined with reverse transcription-polymerase chain reaction analysis (RT-PCR). RESULTS: The trend of changes in gene expression of VEGF, Ang-1, aFGF and bFGF was not same for different skin specimens at various developmental stages. In early gestational fetal skin, genes of VEGF and Ang-1 were strongly expressed, while in late gestational and childhood skins, gene expressions of VEGF and Ang-1 were apparently decreased. In skin of middle gestational stage, the level of aFGF gene expression was highest, and then it was progressively reduced. In childhood skin, this gene was weakly expressed. In marked contrast, the contents of transcripts of bFGF showed no substantial change in fetal skin at different developmental stages, whilst the mRNA content of bFGF was significantly decreased in childhood skin. CONCLUSION: VEGF, Ang-1, aFGF and bFGF might be involved in regulating angiogenesis in skin from fetuses of different gestational stages and children. The relative increase in gene transcription of VEGF and Ang-1 in younger fetal skin might be one of the reasons why cutaneous cells proliferate rapidly and the wounds heal without scar.

Angiogenic Proteins↗
PubMed2004

[Gene expression of stress activated protein kinase and its MAPKs in hypertrophic scar].

OBJECTIVE: To explore the change of gene expression of stress activated protein kinase (SAPK) and its upstream signal-regulated molecule--mitogen activated protein kinases(MAPKs) (MKK4 and MKK7) in hypertrophic scar and auto-control normal skin. METHODS: The total RNA was isolated from 8 hypertrophic scars and 8 auto-control skin, and then mRNA was purified. The gene expressions of MKK4, MKK7 and SAPK were examined with reverse transcription-polymerase chain reaction(RT-PCR) method. RESULTS: In hypertrophic scar, both MKK7 and SAPK genes weakly expressed. In auto-control skin, the expression of these 2 genes was significantly elevated in comparison with hypertrophic scar (P < 0.01). The expression levels of these 2 genes were 1.5 times and 2.6 times as long as those of hypertrophic scar, respectively. Gene expression of MKK4 had no significant difference between auto-control skin and hypertrophic scar (P > 0.05). CONCLUSION: Decreased gene expression of MKK7 and SAPK which results in reducing cell apoptosis might be one of the mechanisms for controlling the formation of hypertrophic scar.

Adolescent↗
PubMed2004

[Expression characteristics of transforming growth factor-beta1 in human skin at different development stages of gestation].

OBJECTIVE: To investigate gene expression of transforming growth factor-beta(1) (TGF-beta(1)) and its two upstream signalling factors (smad2 and smad3) in fetal skin at different gestational ages and postnatal skin and its potential biological significance. METHODS: Fetal skin samples of human embryo were obtained from spontaneous abortions at different gestational ages ranging from 13 to 32 weeks, and also skin collected from patients undergoing plastic surgery. After morphological characteristics of skin at different developmental stages were examined histologically, gene expressions of TGF-beta(1), smad2 and smad3 in skin specimens at different developmental stages were examined with reverse transcription-polymerase chain reaction analysis (RT-PCR). RESULTS: Gene expression of TGF-beta(1), smad2 and smad3 could all be detected in fetal skin and skin after birth. In skin from early gestational fetus, gene expressions of TGF-beta(1) and smad2 were weak. Along with advance in gestational age, gene expression of these two genes in skin became progressively stronger. In skin from late gestational fetus and skin after birth, the transcription contents of these two genes were significantly increased compared with early gestation fetus (P<0.05). On the contrary, gene expression of smad3 was apparently higher in younger fetal skin versus elder compared with that of late fetal skin (P<0.05). In skins after birth, the levels of smad3 gene expression were elevated to the level similar to that in early gestational fetal skin. CONCLUSION: The signal pathway mediated by TGF-beta(1) might be involved in regulating development of the skin at embryonic stage and in designating cetaceous structure and function, and also in wound healing after birth. The relative lack in expression of TGF-beta(1) and smad2 genes in skins from younger fetuses might contribute to fetal scar-less healing, in which the role of smad3 needs to be further investigated.

Actins↗
PubMed2004

[Construction and expression of anti-human integrin alphavbeta3 scFv].

AIM: To construct single chain antibody (scFv) gene of mAb E10 against human integrin alphavbeta3. METHODS: The VH and VL genes were amplified from hybridoma cells secreting mAb E10 by RT-PCR and connected with the use of linker (Gly4Ser)3 to assemble scFv gene. The scFv gene was cloned into prokaryotic expression vector pTIG-TRX and expressed in E. coli BL21 (DE3). RESULTS: SDS-PAGE analysis showed the expressed recombinant protein with relative molecular mass (Mr) being 31,000. Western blot confirmed that the protein was labeled with His6. scFv protein was expressed as soluble protein under the condition of a small amount of IPTG induction and culture at lower temperature. The purity of the protein purified through Ni-NTA agarose metal affinity resin column was over 91%. The purified protein could bind to the human integrin alphavbeta3 by ELISA confirmation. CONCLUSION: scFv against human integrin alphavbeta3 has been successfully constructed and expressed,which lays the foundation for further clinical research.

Amino Acid Sequence↗
PubMed2004

[Changes of intercellular adhesion molecule-1 and E-selectin levels in plasma of uremic patients treated with maintaining hemodialysis].

AIM: To detect the levels of ICAM-1 and E-selectin in plasmas from uremic patients treated by means of maintaining hemodialysis (MHD) and explore the pathological mechanism of atherosclerosis in MHD patients. METHODS: The levels of ICAM-1 and E-selectin in plasmas from the 105 MHD patients and 25 healthy persons (control group) were detected by dual antibody sandwich ELISA. The cervical atherosclerosis of the patients was examined by type B ultrasonography. Simultaneously, the blood pressures of the patients and control group were taken and recorded, as well as the biochemical criterions in their blood were detected. RESULTS: (1) The plasma levels of ICAM-1 and E-selectin in MHD patients were significantly higher than those in the control group, respectively (P < 0.01), and in MHD group the above indexes in patients with cervical atherosclerosis were significantly higher than those without cervical atherosclerosis (P < 0.01,P < 0.05). (2) In MHD group, the plasma ICAM-1 level was positively correlated with E-selectin and triglycerides (TG) levels(r = 0.62 and 0.60, respectively), and with the diastolic pressure(r = 0.41,P < 0.05). CONCLUSION: The impairment of vascular endothelial function was obvious in uremic patients with MHD. The changes of ICAM-1 and E-selectin could be accepted as biochemical criterions of vascular endothelial injury. The two adhesion molecules have close relationship with atherosclerosis in MHD patients.

Adult↗
PubMed2004

Development of gene microarray in screening differently expressed genes in keloid and normal-control skin.

BACKGROUND: Keloid is an intricate lesion that is probably regulated by many genes. In this study, the authors used the technique of complementary DNA (cDNA) microarray to analyse abnormal gene expression in keloids and normal control skins. METHODS: The polymerase chain reaction (PCR) products of 8400 genes were spotted in an array on chemical-material-coated-glass plates. The DNAs were fixed on the glass plates. The total RNAs were isolated from freshly excised human keloid and normal control skins, and the mRNAs were then purified. The mRNA from both keloid and normal control skins were reversely transcribed to cDNAs, with the incorporation of fluorescent dUTP, for preparing the hybridisation probes. The mixed probes were then hybridised to the cDNA microarray. After thorough washing, the cDNA microarray was scanned for differing fluorescent signals from two types of tissues. Gene expression of tissue growth factor-beta1 (TGF-beta1) and of c-myc was detected with both RT-PCR and Northern blot hybridisation to confirm the effectiveness of cDNA microarray. RESULTS: Among the 8400 human genes, 402 were detected with different expression levels between keloid and normal control skins. Two hundred and fifty genes, including TGF-beta1 and c-myc, were up-regulated and 152 genes were down-regulated. Higher expressions of TGF-beta1 and c-myc in keloid were also revealed using RT-PCR and Northern blot methods. CONCLUSION: cDNA microarray analysis provides a powerful tool for investigating differential gene expression in keloid and normal control skins. Keloid is a complicated lesion with many genes involved.

DNA, Complementary↗
PubMed2004

[Analysis of etiological factors of pseudo-epitheliomatous granuloma after cutaneous wound healing: a report of 11 cases of patients with this lesion].

OBJECTIVE: To explore the pathogenetic mechanism, clinical and pathological characteristics, and prevention and treatment of pseudo-epitheliomatous granuloma after skin wound healing. METHODS: The clinical information and the treatment results of pseudo-epitheliomatous granuloma occurring in 11 patients (age 1-67 years) were reviewed and analyzed, their tissue specimens were used for microbial examination and histological observation. RESULTS: Some bacteria such as Staphylococcus aureus, Pseudomonas aeruginosa, Streptococcus hemolyticus B, and Streptococcus faecalis could be found in the culture of pseudo-epitheliomatous granuloma. The maJority of these bacteria was tolerant to celbenin but sensitive to vancomycin. The lesions were excised, and the wounds were covered with skin grafting or skin flap, supplemented by local of vancomycin to prevent recurrence of the lesion. Histological examination revealed in pseudo-epitheliomatous granuloma with long epithelial peduncle encapsulating granulation tissue like honeycomb, in which there were many capillaries, macrophages, lymphocytes and mast cells, with only a small amount of extracellular matrix. CONCLUSION: The main pathogenesis of pseudo-epitheliomatous granuloma formation might be improper treatment of wound in earlier period and infection of drug resistant bacteria. Surgical debridement followed by skin coverage and local inJection of vancomycin could be effective and curative.

Adolescent↗
PubMed2004

[Effects of reconstructive human acidic fibroblast growth factor and wild type acidic fibroblast growth factor on skin cell proliferation].

OBJECTIVE: To investigate the effects of reconstructive human acidic fibroblast growth factor (aFGF) and wild type aFGF on skin cell proliferation in rat. METHODS: Neonatal rat skin (area of 2 mmx2 mm) was cultured in Dulbecco's modification of Eagle's medium containing reconstructive human aFGF and wild type aFGF, respectively. The concentrations of aFGF were 1 microg/L, 10 microg/L, and 100 microg/L. After being cultured for 4 days, the area of skin was measured. RESULTS: After treatment with two different growth factors in three different concentrations (1 microg/L, 10 microg/L and 100 microg/L) for 4 days, the areas of skin in three reconstructive human aFGF groups were 1.4, 1.5 and 1.3 fold of that of control, respectively and the areas of three wild type aFGF groups were 1.5, 3.2 and 1.6 fold of that of control, respectively, while the area of skin in the control group was (2.96+/-1.12) mm(2). In comparison with those of other groups, the skin area of 10 microg/L wild type aFGF group was significantly increased (P<0.05). CONCLUSION: Reconstructive human aFGF confers less impact on cutaneous cell growth. The capability of wild type aFGF to induce cutaneous cell proliferation is much greater than that of reconstructive human aFGF.

Animals↗
PubMed2004

[Clinical application of multifocal intraocular lens].

OBJECTIVE: To study the results of using multifocal intraocular lens (MIOL) for the treatment of cataract. METHODS: After the small incision phacoemulsification, MIOL was inserted into the eye in 30 cases (36 eyes, test group); single-focal intraocular lens (SIOL) was inserted in 32 cases (40 eyes, control group). Visual acuity, focal depth, corneal astigmatism, contrast sensitivity, glare sensitivity, operative complications and untoward visual symptoms were observed. The follow-up period was 6.0 approximately 18.0 months. RESULTS: Percentage of patients with uncorrected near visual acuity 0.5 or better accounted was 80.6% (29/36) in the test group and 25.0% (10/40) in the control group, there was a significantly statistical difference between these two groups 6 months postoperatively (P < 0.05). There was no significantly statistical difference between the corrected near and far visual acuity and uncorrected far visual acuity of these two groups (P > 0.05). In patients with +1.00 - -1.00 D accommodation power, the percentage of patients with visual acuity 0.5 or better was 97.2% (35/36) in the test group and 97.5% (39/40) in the control group, there was no significantly difference between these two groups (P > 0.05). In patients with -1.50 D and -2.50 - -3.50 D accommodation power, the percentage of patients with visual acuity 0.5 or better was 97.2% (35/36) and 88.9% (32/36) in the test group, respectively; which was significantly greater than those in the control group [0.0% (0/40) and 0.0% (0/40), respectively] (P < 0.05). In patients with visual acuity 0.5 or better, the depth of focus was 4.50 D in 86.11% cases of the test group and was 2.00 D in 97.5% cases of the control group. There was no statistically significant difference between the preoperative corneal stigmatism and corneal astigmatism 1 week, 1 month, 3 months and 6 months after the operation in both groups (P > 0.05). Low frequency contrast sensitivity and glare sensitivity (28.49 +/- 6.45 and 16.97 +/- 4.40, respectively) in the test group were significantly lower than those of the control group (36.20 +/- 7.45 and 24.05 +/- 6.08, respectively) (P < 0.05). There was no significantly statistical difference in medium and high frequency contrast sensitivity and glare sensitivity between these two groups (P > 0.05). Two eyes needed Nd:YAG laser posterior capsulotomy in both groups. Two patients (5.6%) with unilateral MIOL complained glare at night. CONCLUSION: MIOL implantation is a safe and effective method for the treatment of cataract. MIOL has a distinct advantage in providing a full-distance visual acuity.

Female↗
PubMed2004

[Molecular characteristics of Acanthamoeba strains from keratitis patients].

OBJECTIVE: To study the molecular characteristics of Acanthamoeba strains isolated from keratitis patients. METHODS: Twenty six Acanthamoeba strains were isolated from corneal ulcers between 1994 and 2002. Partial genome DNA sequences of all strains of Acanthamoeba were amplified using PCR and then the PCR products were sequenced. The partial DNA sequences were analyzed by software Clustal X and MEGA2. The results of Acanthamoeba obtained from Beijing Tongren Hospital were compared with strains from other countries and districts. RESULTS: Of 26 Acanthamoeba strains isolated from the patients, 25 (96%) were 18S rDNA (Rns) genotype T4 and one (4%) was T3. These results were similar to those obtained from other countries and districts. CONCLUSIONS: According to the Rns genotype classification criterion, most of Acanthamoeba strains isolated from keratitis patients in Beijing are genotype T4 and only few of these strains are genotype T3. The Acanthamoeba infecting the cornea might belong to the specific 18S rDNA genotype.

Acanthamoeba↗
PubMed2004

[Sutureless lamellar keratoplasty by microkeratome combined with fibrin tissue adhesive in rabbits].

OBJECTIVE: To evaluate the feasibility and safety of sutureless lamellar keratoplasty by microkeratome combined with fibrin tissue adhesive. METHODS: Twenty-four New Zealand white rabbits were divided into two groups, the donor grafts and recipient beds were made by the microkeratome, the grafts were glued over the stoma bed using the commercial product Tisseel in one group; and grafts without tissue adhesive were used as the control group. Corneal refractive power was measured by automated keratometer preoperatively and in 3 days, 2 weeks, 1 and 3 months postoperatively. Rejection and cornea transparency were observed. Confocal microscopy was used to observe corneal wound healing response and to measure the keratocyte and endothelium densities in vivo. Corneal wound healing was also evaluated using light and fluorescence microscopy. RESULTS: Ninety-two percent (11/12 eyes) of the glued grafts were retained in the Tisseel group, whereas all grafts were lost in the control group. All survived grafts were clear 1 month after surgery. However, in the control group, severe haze in the grafts occurred 2 weeks postoperatively. Confocal microscopy showed that there was a significant decrease of the keratocyte density surrounding the lenticule-host interface, and no changes occurred in the posterior keratocyte and endothelium. Histopathologic observations demonstrated the presence of a line of amorphous eosinophilic substance in the lenticule-host interface at 3 days after surgery, but the line disappeared after 1 month. Fluorescence microscopy showed no detectable regenerated stromal tissue. CONCLUSIONS: This initial study demonstrates sutureless optical lamellar keratoplasty performed by microkeratome combined with fibrin tissue adhesive is a simple and safe technique. Stromal wound healing response to this surgery is minimal. Fibrin tissue adhesive has no influence on the cornea optical property.

Animals↗