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Biomedical subjects

Yu Chen

Publications and source records attributed to Yu Chen.

At least 271 records · Page 15Linked to original sources
PubMed2002

VEGF enhances functional improvement of postinfarcted hearts by transplantation of ESC-differentiated cells.

Despite considerable advances in medicine, the incidence of heart failure remains high in patients after myocardial infarction (MI). This study investigated the effects of engrafted early-differentiated cells (EDCs) from mouse embryonic stem cells, with or without transfection of vascular endothelial growth factor (VEGF) cDNA (phVEGF(165)), on cardiac function in postinfarcted mice. EDCs were transfected with green fluorescent protein (GFP) cDNA and transplanted into infarcted myocardium. Compared with the MI mice receiving cell-free medium, cardiac function was significantly improved in the MI mice 6 wk after transplantation of EDCs. Moreover, improvement of heart function was significantly greater in the mice implanted with EDCs overexpressing VEGF (EDCs-VEGF) than with EDCs alone. Frozen sections of infarcted myocardium with EDCs or EDCs-VEGF transplantation showed GFP-positive tissue. The area with positive immunostaining for cardiac troponin I and alpha-myosin heavy chain was larger in injured myocardium with EDCs or EDCs-VEGF transplantation than with medium injection. Transplantation of EDCs or EDCs-VEGF significantly increased the number of blood vessels in the MI area. However, the density of capillaries was significantly higher in the EDCs-VEGF animals than in the EDC mice. Double staining for GFP and connexin-43 was positive in injured myocardium with EDC transplantation. Our data demonstrate that engrafted EDCs or EDCs-VEGF regenerated cardiac tissue and significantly improved cardiac function in postinfarcted hearts. The novel EDCs-VEGF synergistic approach may have an important impact on future cell therapy for patients experiencing MI or heart failure.

Animals↗
PubMed2002

Effect of prolonged uremia on insulin-like growth factor-I receptor autophosphorylation and tyrosine kinase activity in kidney and muscle.

Recently, based on a study in rats with chronic renal failure (CRF), it has been suggested that IGF-I resistance in uremia may be caused in part by defective IGF-I receptor autophosphorylation and tyrosine kinase activity. Thus if such a defect were to develop in prolonged acute renal failure (ARF), this may explain why IGF-I therapy, effective in rats, has failed to promote recovery from ARF in patients. Accordingly, we examined IGF-I receptor function in rats with uremia of increasing duration and in pair-fed sham-operated controls. After 6 days of prolonged ARF, kidney IGF-I receptor binding increased twofold, while IGF-I stimulated receptor phosphorylation and tyrosine kinase activity were unchanged. Muscle receptor binding, autophosphorylation and tyrosin kinase activity were similar to control values after 6 or even 21 days of uremia. Taking all these findings together it appears that IGF-I resistance in uremia cannot be attributed to a receptor defect. This in turn argues against altered receptor function as a cause of the failure of IGF-I to modify clinical ARF.

Acute Kidney Injury↗
PubMed2002

[Clinical significance of plasma homocysteine in the coronary atherosclerosis patients]

OBJECTIVE: To investigate the clinical significance of plasma homocysteine Hcy in patients with coronary atherosclerosis. METHODS Plasma Hcy levels of 85 patients with coronary atherosclerosis and 68 normal controls were determined by fluorescence polarization immunoassay. RESULTS The mean levels of plasma Hcy were (9.31+/-3.80)&mgr;mol/L in normal controls and (13.39+/-6.06)&mgr;mol/L in patients with coronary atherosclerosis. That was (11.36+/-3.86)&mgr;mol/L in the patients with micro-pathological changes of coronary artery, (13.32+/-6.09)&mgr;mol/L with single-vessel disease,(13.39+/-4.92)&mgr;mol/L with double-vessel disease, and (18.23+/-8.98)&mgr;mol/L with three-vessel disease by coronary angiography. Statistically, the mean plasma Hcy concentrations in male and female patients was higher than that in the corresponding control subjects(13.77+/-6.68 compared with 10.50+/-4.07, 11.50+/-3.58 compared with 7.80+/-2.85 &mgr;mol/L,P<0.001 respectively). CONCLUSION The patients with coronary atherosclerosis present hyperhomocysteinemia is very important to determine plasma homocysteine for diagnosis and therapy in the patients with coronary heart disease.

Journal Article↗
PubMed2002

[Effect of nutritional state on cardiopulmonary exercise performance in patients with chronic obstructive pulmonary disease].

OBJECTIVE: To explore the effect of nutritional state on cardiopulmonary exercise performance of chronic obstructive pulmonary disease (COPD) patients. METHODS: 43 COPD patients and 20 healthy controls performed incremental cardiopulmonary exercise testing with cycle ergometer. Nutritional assessment and routine lung function studies were performed in all subjects before testing. RESULTS: (1) Compared with the normally nourished COPD group, the malnourished group showed greater reduction in Wmax, VO(2)max, O(2)pulsemax, and AT (P < 0.05), whereas VO(2)/W/V(E) and DImax were higher in the malnourished group (P < 0.05). (2) IBW% was positively correlated with VO(2)max, Wmax, O(2)pulsemax, AT (r = 0.696, 0.432, 0.717, 0.822, P < 0.01), and negatively correlated with DImax and VO(2)/W/V(E) (r = -0.450, -0.640, P < 0.01) in COPD patients. CONCLUSION: Malnutrition adversely affected muscle aerobic capacity and exercise tolerance in COPD patients.

Adult↗
PubMed2002

A study on the relationship between genetic and environmental factors of type 2 diabetes mellitus in humans.

OBJECTIVE: To study the relationship between the inheritable factor and environmental factors of type 2 diabetes mellitus in humans. METHODS: A case-control study based on 154 type 2 diabetes mellitus and 130 healthy controls was carried out in Jiangsu Province in 1997. RESULTS: The age, family history of diabetes mellitus, hypertension history, high waist/hip ratio (WHR), high systolic blood pressure, huge fetus history, and the genotype of beta(3)-adrenergic receptor (beta(3)-AR) were the risk factors of type 2 diabetes mellitus; while occupational physical activity was protective factor of type 2 diabetes mellitus. The risk for diabetes mellitus distinctly increased while genetic factor and obesity, beta(3)-AR mutation were coexisting. CONCLUSION: Type 2 diabetes mellitus is caused by the effect of both genetic and environmental factors.

Aged↗
PubMed2002

[Anticancer effect of hydroxycampothecin on oral squamous carcinoma cell line].

BACKGROUND & OBJECTIVE: Studies have demonstrated that hydroxycamptothecin (HCPT) had therapeutic effect on many malignant tumors, but few studies on oral squamous cell carcinoma were reported. This study was designed to investigate the anticancer effect and mechanism of hydroxycampothecin (HCPT) on oral squamous carcinoma cell line (Tca8113). METHODS: The cytotoxicity of HCPT on Tca8113 cell line was measured by MTT assay and cell cycle detected by flow cytometry(FCM). The growth status of Tca8113 cell xenografts following treatment with HCPT was observed. The doubling times and tumor inhibition rate were calculated. RESULTS: HCPT had strong cytotoxicity on Tca8113 cells, the IC50 was 2 mumol/L. After treatment with low concentration of HCPT, the cell cycle was arrested in S phase or G2 + M phase; while at high concentration, apoptosis was obviously found and the rate of apoptosis was increased as the time and concentration of HCPT. Compared with control group, the xenografts of HCPT treated group grew slower and tumor doubling time was prolonged, The tumor volumes of HCPT treated group at 28th day were significantly smaller(P < 0.001) with tumor inhibition rate of 69.6%. CONCLUSION: The result showed that HCPT had strong cytotoxicity effect to oral squamous carcinoma cells and significant growth inhibition on Tca8113 xenografts. HCPT can arrest cell cycle in S phase and G2 + M phase and induce cell apoptosis.

Animals↗
PubMed2002

[Sonographic diagnosis of carotid body tumor].

OBJECTIVE: To analyse the features of gray scale and colour Doppler sonography for carotid body tumor, to improve the sonographic diagnostic accuracy. METHODS: A retrospective review was performed of sonographic material of 18 carotid body tumors by gray scale sonography and 11 by colour Doppler sonography, with comparison with other diseases which are frequently misdiagnosed as carotid tumor. RESULTS: Well-defined, even weakly hypoechoic masses were noted on gray scale ultrasonogram at the carotid bifurcation, commonly broadening the carotid bifurcation and often encasing the common, external and internal carotid arteries. Disorderly non-echoic channel- like structures in the tumor were sometimes observed. Colour Doppler sonography showed abundant flow in the tumor. The non-echoic channel- like structures were vascularities. Seventeen masses diagnosed by ultrasound were proved to be carotid body tumors. The other was confirmed as a neurogenic tumor, giving an accuracy rate of 94.4% for sonographic diagnosis. CONCLUSION: Sonographic examination of the carotid body tumor is highly accurate. It is safe and reliable.

Adult↗
PubMed2002

[Study on application of arbuscular-mycorrhizas in growing seedings of Aloe vera].

Tissue culture seedlings of Aloe vera L. inoculated with 7 AMF(arbuscular mycorrhiza fungi) in a greenhouse in Guangzhou showed that the percentage of infection was 99.67%-100%, the index of infected was 73.3%-86.67%. After being inoculated 13 months, the seedling high raised 19.88%-51.91%, the leaves length raised 13.13%-150.96%. After being inoculated 15 months, the leaves juice of Aloe vera raised 60.87%-233.8% and the dried of leaves juice raised 217%-724%.

Aloe↗
PubMed2002

[Comparative study on regulation patterns of compound prescriptions for kidney tonifying and for blood circulation activating on T-cell apoptosis related gene expression in aged rats].

OBJECTIVE: To investigate the regulation pattern of the two compound prescriptions for Kidney tonifying, Yougui Yin and Bushen Yishou capsule, in down-regulating T-cell apoptosis gene expression in aged rats. METHODS: Expressions of T-cell apoptosis promoting and inhibiting genes, including Fas, FasL, Bcl-2, Bax, TNFR1 and TNFR2, as well as activity of cysteine proteinase in cascade connection, such as Caspase 8 and Caspase 3 were determined by TUNEL labeled flow cytometry and fluorescence real-time quantitative RT-PCR technique. The difference between old and young rats was compared, and the different regulation patterns of the two compound prescriptions for Kidney tonifying and their effects on Caspase activity were compared with those of compound prescription for blood circulation activating. RESULTS: The two compound prescriptions for Kidney tonifying could effectively lower T-cell over-apoptosis in old rats, down-regulate FasL and TNFR1 gene transcription, and decrease the activity of Caspase 8 and Caspase 3, while the compound prescription for blood circulation activating showed insignificant effect on T-cell over-apoptosis. CONCLUSION: Kidney-deficiency is closely related to the T-cell over-apoptosis. The T-cell over-apoptosis in old rats could be effectively improved by the two compound prescription for Kidney tonifying through down-regulating the apoptosis promoting genes FasL and TN-FR1 transcription. That is the unique regulation pattern of Kidney tonifying principle to T-cell apoptosis related gene in old rats.

Aging↗
PubMed2002

[Comparative study of modulating effect of kidney tonifying recipe and spleen invigorating recipe on T-lymphocyte apoptosis in corticosterone treated rats].

OBJECTIVE: To compare the modulating effect of Kidney tonifying recipe (KTR) and Spleen invigorating recipe (SIR) on T-lymphocyte apoptosis (TLA) in corticosterone treated rats (CTR). METHODS: Qualitative and quantitative analysis on activation-induced TLA was conducted by transmission electron microscope and TUNEL labelled flow cytometry detection. RESULTS: TLA percentage of CTR was 45.87 +/- 7.22%, while that of normal control rats was 34.25 +/- 6.47%, the difference between them was significant (P < 0.01). TLA percentage of Youguiyin treated rats was 35.90 +/- 7.39%, and that of Bushen Yishou capsule treated rats was 36.20 +/- 9.14%, compared with that of CTR, P < 0.01 and P < 0.05 respectively. TLA percentage of the SIR treated group was 36.92 +/- 11.82%, which was different insignificantly as compared with that of CTR. CONCLUSION: TLA susceptibility was significantly enhanced in CTR. Both KTRs (Youguiyin and Bushen Yishou capsule) had down-regulating effect on TLA, while the effect of SIR was insignificant, suggesting that down-regulating activation-induced TLA may be one of the important mechanisms of KTR in improving T-lymphocyte function in CTR.

Animals↗
PubMed2002

[Abdominal and pelvic lymph nodes in non-Hodgkin lymphoma: the nodal distribution in Chinese patients].

OBJECTIVE: To study the distribution of abdominal and pelvic lymph nodes involved in non-Hodgkin lymphoma in Chinese patients. METHODS: CT images of 241 non-Hodgkin lymphoma patients with abdominal and pelvic lymph nodes involved were reviewed. Of them, 96 patients whose clinical and image data fulfilled the requirements of the analysis were included: 1. Positive abdominal and/or pelvic nodular lesion in untreated patients examined by CT (n = 74). 2. New lesions in abdominal or pelvic lymph nodes who never had any nodular lesion by previous abdominal and/or pelvic CT (n = 14). 3. Treated patients who did not have abdominal and/or pelvic CT before, showed regression of initial disease for at lease 6 months after chemotherapy and patients showing abdominal and/or pelvic nodal lesions (n = 8) were assessed. In accordance with Clinical Schema for the Lymphoid System, these patients were divided into 3 histology subtypes: indolent (IL; n = 31), aggressive (AL; n = 61) and very aggressive (VAL; n = 2) lymphoma. The remaining 2 cases were unclassified (UCL). Both abdominal and pelvic CT scans were undertaken in 46 patients, abdominal CT only in 47 patients and pelvic CT only in 3 patients. Enhanced CT with i.v. contrast was obtained in 80 patients. The anatomic sites involved were designated as retroperitoneal (i.e. paraaortic), mesenteric, abdominal (i.e. celiac, paracardiac, gastrohepatic, and hepatic hilar, etc), retrocrural, subdiaphragmatic, common iliac, internal iliac, external iliac, and inguinal nodes, respectively. RESULTS: The lesions were located in the retroperitoneum, with an incidence of 83% for both IL and AL. These were predominantly seen superior and inferior to the renal hila, with incidences of 72.0% (18/25) in IL and 67.3% (33/49) in AL. Pelvic lymph nodes came the next, with incidences of 41.9% (126/301 sites of IL and AL), 57.5% (50/87 sites) in IL and 35.5% (76/214 sites) in AL. Mesenteric lymph nodes stood third with incidences of 37.1% (33/89 IL and AL), 43.3% (13/30) in IL and 33.9% (20/59) in AL. There was only one statistically significant evidence that the external iliac lymph nodes were much more commonly seen in IL than in AL (P < 0.05). CONCLUSION: In Chinese patients, retroperitoneal, iliac, and mesenteric nodes are the most commonly involved lymph nodes in NHL. The involved retroperitoneal lymph nodes are predominantly located superior and inferior to the renal hila. The anatomic distribution of abdominal and pelvic lymph nodes in NHL of Chinese patients is different from that of the western countries.

Abdomen↗
PubMed2002

[Expression of rat protamine gene in MEL cells].

OBJECTIVE: To investigate the expression of rat protamine (RP) gene in MEL cells and the effect on cell growth. METHODS: Eukaryotic expression plasmid pCR-3.1-RP was constructed and transfected into MEL cells. The changes of cell growth rate, mitotic index and colony-forming rate in semi-solid medium were investigated. RESULTS: Transfected MEL cells showed lower growth rate, mitotic index and colony-forming rate. Volumes of cells were reduced and reduction of RNA transcription was observed. CONCLUSION: These results suggest that expression of RP in MEL cell may inhibit the cell growth and proliferation.

Animals↗
PubMed2002

Determination of low level HBsAg in serum by microparticle enzyme immunoassay.

OBJECTIVE: To investigate the distribution of the population with low level HBsAg in serum and the characteristics of their HBV serologic markers. METHODS: We detected HBsAg, HBeAg, anti-HBc, anti-HBe, and anti-HBs in the serum samples from 8089 non-hepatitis inpatients and defined the patients with HBsAg concentration equal to or less than 5 microg/L by using the AxSYM microparticle enzyme immunoassay (MEIA) system. RESULTS: 189 patients with HBsAg equal to or low than 5 microg/L (2.34% of all 8089 patients and 23.16% of 816 HBsAg positive patients) included 84 (44.40%), 33(17.5%) and 72 (38.10%) with HBsAg equal to or less than 1 microg/L, 1-2 microg/L and 2-5 microg/L respectively. Most of these patients were detected with "positive for HBsAg, anti-HBc and anti-HBe but negative for HBeAg and anti-HBs", and anti-HBc antibodies were frequently present in their sera. CONCLUSIONS: The population with low level HBsAg in serum should not be neglected and it is important to improve the test sensitivity of HBsAg and to detect the other HBV serologic markers.

Hepatitis B Antibodies↗
PubMed1998

Relationship between different sources of drinking water, water quality improvement and gastric cancer mortality in Changle County-A retrospective-cohort study in high incidence area.

AIM:To investigate the relationship between different sources of drinking water supply, water quality improvement and gastric cancer mortality rate in a high risk area.METHODS: A retrospective-cohort survey was carried out in all towns of this county to study the effect of different sources of drinking water supply and water quality improvement on gastric cancer mortality rate.RESULTS: The gastric cancer mortality rate among the population 124.05/10(5) drinking river water was obviously higher than that of drinking shallow well water (74.85/10(5)) (P < 0.01) according to the Zhanggang Town 16 years accumulated data. The same pattern was presented in 7 towns after balancing the confounders. The gastric cancer mortality rate of population drinking river water was 86.03/10(5), which was higher than those drinking shallow well water (62.03/10(5)) and tap water (29.78/10(5))(P < 0.01). When the drinking water switched from river and well water to tap water, the gastric cancer incidence decreased to 30.33/10(5) and 26.10/10(5), and the gastric cancer mortality decreased by 59% and 57% respectively.CONCLUSION: The quality of drinking water is one of the important factors of increased incidence of gastric cancer in Changle County, and water quality improvement has a beneficial effect, but the cause of high gastric cancer incidence may be multi-factorial in this area.

Journal Article↗
PubMed1996

Cloning of the LAC4 Promoter from K. lactis and Studies on the Function of its UASII.

The -661 - +21 bp region of the LAC4 gene form K. lactis CBS141 was obtained by PCR technique and fused with the lacZ gene from E. coli to construct and expression vector YFD 114. It was then transformed into K. lactis Y167. The function of the cloned LAC4 promoter was tested by induction with galactose, lactose, sorbitol or IPTG. The results revealed that galactose had higher inducing effect than lactose while sorbitol and IPTG had no inducing effect. The insertion of chemically synthesized LAC4 UASII at just the upstream of the cloned LAC4 promoter could increase its basic and induced expression level. The extents of increase were different with the orientation and the copy number of the inserted UASII.

Journal Article↗
PubMedDate not supplied

Traceless solid-phase synthesis of nitrogen-containing heterocycles and their biological evaluations as inhibitors of neuronal sodium channels.

The preparation of pyrimidine-2-thione, pyrimidine-2-one, pyrimidine, and benzo[b][1,4]diazepine derivatives using traceless solid-phase sulfone linker strategy is described. Key steps involved are (i) sulfinate S-alkylation, (ii) sulfone anion alkylation with an epoxide, (iii) gamma-hydroxyl sulfone --> gamma-ketosulfone oxidation, and (iv) traceless product release by a one-pot elimination-cyclization process. Elimination-cyclization was carried out under basic conditions with thiourea, methyl thiourea, methyl urea, guanidine hydrochloride, benzamidine hydrochloride and ortho-phenylene diamine. Twenty-three compounds were prepared, and 14 of them were evaluated by the Batrachotoxin (BTX) radioligand binding assay for their binding affinity to neuronal sodium channels. Compound 7c was found to be a potential neuronal sodium channels blocker.

Animals↗