Biomedical subjects

Hong Chen

Publications and source records attributed to Hong Chen.

At least 217 records · Page 12Linked to original sources

PubMed2003

An algorithm for three-way data analysis that alternatively minimizes coupled vector (COV) resolution error and PARAFAC error.

A novel algorithm, alternatively minimizing coupled vector (COV) resolution error and PARAFAC error algorithm, is proposed in this paper. This algorithm can overcome the problem of slow convergence and is insensitive to the estimation of component number, such problems are unavoidable while using the traditional parallel factors analysis (PARAFAC) algorithm. In other words, this algorithm is capable of improving the computing speed and providing accurate resolutions provided that the number of factors used in the computation is no less than that of the actual underlying ones. The characteristic performances were demonstrated with a novel fluorescence data array.

Journal Article↗

PubMed2003

Prevalence and costs of major depression among elderly claimants with diabetes.

OBJECTIVE: To compare the odds of major depression among Medicare claimants with and without diabetes and to test whether annual medical payments are greater for those with both diabetes and major depression than for those with diabetes alone. RESEARCH DESIGN AND METHODS: This retrospective analysis relies on claims data from the 1997 Medicare 5% Standard Analytic Files. Using these data, we statistically determined whether the odds of major depression are greater among elderly claimants with diabetes after controlling for age, race/ethnicity, and sex. We then used regression analysis on a sample of over 220,000 elderly claimants with diabetes to test whether payments for non-mental health-related services are greater for those with both diabetes and major depression (n = 4,203) than for those with diabetes alone. RESULTS: Our findings indicate that the odds of major depression are significantly greater among elderly Medicare claimants with diabetes than among those without diabetes (OR 1.58 +/- 0.05). We also found that elderly claimants with both diabetes and major depression seek treatment for more services and spend more time in inpatient facilities, and as a result incur higher medical costs than claimants with diabetes but without major depression. These results hold even after excluding services related to mental health treatment. CONCLUSIONS: This analysis suggests that treatment for major depression among claimants with diabetes may reduce total medical costs if treatment results in a decrease in utilization for general medical services in the future.

Aged↗

PubMed2003

Alterations of p53 and PCNA in cancer and adjacent tissues from concurrent carcinomas of the esophagus and gastric cardia in the same patient in Linzhou, a high incidence area for esophageal cancer in northern China.

AIM: To characterize the alteration and significance of p53 and PCNA in cancer and adjacent tissues of concurrent cancers from the esophagus and gastric cardia in the same patient. METHODS: P53 and PCNA protein accumulation in 25 patients with concurrent cancers from the esophagus and gastric cardia (CC, concurrent carcinomas of esophageal squamous cell carcinoma and gastric cardia adenocarcinoma) were detected by immunohistochemical method (ABC). RESULTS: In CC patients, both esophageal squamous cell carcinoma (SCC) and gastric cardia adenocarcinoma (GCA) tissues showed different positive immunostaining extent of p53 and PCNA protein (P>0.05). The positive immunostaining rates for p53 and PCNA were 60 % (15/25) and 92 % (23/25), respectively in SCC; and 40 % (10/25) and 88 % (22/25), respectively in GCA. "Diffuse" immunostaining pattern was frequently observed in both p53 and PCNA. High coincidence rates for p53 and PCNA positive staining were observed in SCC and GCA from the same patients, and accounted for 56 % and 96 %. In SCC patients, with the lesions progressed from normal esophageal epithelium (NOR) to basal cell hyperplasia (BCH) to dysplasia (DYS) to carcinoma in situ (CIS) to SCC, the positive rates for p53 were 27 %, 50 %, 50 %, 29 % and 72 %, and 55 %, 70 %,75 %, 71 % and 93 % for PCNA, respectively. In GCA, with the lesions progressed from normal gastric cardia epithelium to DYS to CIS to GCA, the positive rates of p53 expression were 44 %, 27 %, 22 % and 36 % respectively, the difference was not significant; the positive rates of PCNA protein expression were 67 %, 64 %, 67 % and 86 %, respectively. The chi(2) test, Fisher's Exact Test, Mantel-Haenszel chi(2) Test and Kappa Test were used for the statistics. CONCLUSION: The high coincident alterations for P53 and PCNA in SCC and GCA from the same patient indicate the possibility of similar molecular basis, which provides important molecular basis and etiological clue for similar geographic distribution and risk factors in SCC and GCA.

Adenocarcinoma↗

PubMed2003

Genetic diversity and multiple infections of Plasmodium vivax malaria in Western Thailand.

Using two polymorphic genetic markers, the merozoite surface protein-3alpha (MSP-3alpha) and the circumsporozoite protein (CSP), we investigated the population diversity of Plasmodium vivax in Mae Sod, Thailand from April 2000 through June 2001. Genotyping the parasites isolated from 90 malaria patients attending two local clinics for the dimorphic CSP gene revealed that the majority of the parasites (77%) were the VK210 type. Genotyping the MSP3-alpha gene indicated that P. vivax populations exhibited an equally high level of polymorphism as those from Papua New Guinea, a hyperendemic region. Based on the length of polymerase chain reaction products, three major types of the MSP-3alpha locus were distinguished, with frequencies of 74.8%, 18.7%, and 6.5%, respectively. The 13 alleles distinguished by restriction fragment length polymorphism analysis did not show a significant seasonal variation in frequency. Genotyping the MSP-3alpha and CSP genes showed that 19.3% and 25.6% of the patients had multiple infections, respectively, and the combined rate was 35.6%. Comparisons of MSP-3alpha sequences from nine clones further confirmed the high level of genetic diversity of the parasite and also suggested that geographic isolation may exist. These results strongly indicate that P. vivax populations are highly diverse and multiple clonal infections are common in this malaria-hypoendemic region of Thailand.

Alleles↗

PubMed2003

[Effects of three different immunosuppressive drugs on SD rat islet cell viability].

OBJECTIVE: To investigate the effect of immunosuppressive drugs on the viability of pancreatic islet cells cultured in vitro, and to explore their effects on the outcome of islet transplantation. METHODS: Pancreatic islet cells from SD rats were cultured in vitro, and the changes in their viability determined by MTT assay after incubation with immunosuppressive drugs at different concentrations. RESULTS: The viability of the islet cells was reduced after exposure to rapamycin at higher concentrations (>or= 1 ng/ml), but not at lower concentrations. Treatment with daclizumab and FTY720, at either lower or higher concentrations, did not result in significant reduction of the islet viability. CONCLUSIONS: Rapamycin may directly cause damage to islet cells, the degree of which is positively correlated to the concentration of rapamycin. No obvious toxicity of daclizumab and FTY720 was observed against the islet cells.

Animals↗

PubMed2003

[Sequences analysis of cytochrome C oxidase subunit I gene in Aedes albopictus from different geographic strains in China].

OBJECTIVE: To compare the sequences of cytochrome C oxidase subunit I gene (COI) in Aedes albopictus from different geographic strains in China and to discuss the differences in susceptibility among different geographic strains to dengue virus (DV). METHODS: COI was amplified with polymerase chain reaction method and sequenced from its genomic DNA. Molecular phylogenetic trees were constructed with Neighbor-Joining method. RESULTS: Sequence length of COI fragment in each geographic strains was 415 bp. The rates of shift and reverse of base pairs in Simao strain were 1.93% and 0.24% respectively. The rate of shift in Mawei and Nanning strains was 0.48%. The analyses of phylogenetic of COI sequences showed that there was close relationship between Simao strain in Yunnan and Mawei strain in Guizhou and between Mawei strain and Nanning strain in Guangxi. CONCLUSIONS: The susceptibility was widely related to many factors including genetic and environmental ones. COI in Aedes albopictus from different geographic strains in China belonged to the same gene type. There were no direct correlations between COI gene type in different geographic strains and susceptibility to DV.

Aedes↗

PubMed2003

[Application of virtual reality modeling language in the fields of medical digital image].

This research aims at the process of three-dimensional(3D) reconstruction from medical body data using VRML and VC++, JavaScript language and focuses on the application of VRML for 3D reconstruction of medical digital images. The 2D medical digital images firstly are modified in VC++ language. Then, the images are manipulated by mould built in VRML and modified in JavaScript language. Finally, the 3D reconstruction of body internal organs can be formed in high quality near to those got in traditional methods. Furthermore, VRML browser can offer better windows of man-computer interaction in real time environment. As a new method and tool quite different from traditional ways of 3D reconstruction, VRML is useful for the visualization of medical 3D reconstruction based on 2D images and has a promising prospect in the field of medical image.

Image Processing, Computer-Assisted↗

PubMed2003

[Gamma knife radiosurgery for hemangioblastomas: clinical results and pathological findings].

OBJECTIVE: To retrospectively evaluate the effects of Gamma knife in the treatment of cerebral hemangioblastomas. METHODS: From 1993 to 1996, seventeen patients with 29 hemangioblastomas were treated with Gamma knife. The patients mean age was 35 years (range: 16 - 61 years). The mean tumor diameter was 16 mm (range: 6 - 55 mm). Thirteen patients had recurrent or residual hemangioblastomas. Four with primary hemangioblastomas were diagnosed using CT, MRI and DSA. The maximum dose to the tumors was 21.0 - 50.0 Gy, with mean dose of 33.7 Gy. The radiation dose to the periphery of tumors was 12.0 - 24.0 Gy, with mean dose of 17.6 Gy. RESULTS: All the patients had been followed up for 18 to 62 months, with mean 46 months. Five patients experienced clinical improvement and reduction in tumor volume, and 5 remained stable and tumor unchanged in volume during the follow-up period. Three patients died of tumor progression, surgery and cancer after treatment 18, 22, 25 months respectively. Four patients underwent surgery respectively at 3, 4, 29 and 48 months after gamma knife operation. The local control rate of the tumors at 1 year was 92%, 2 years 88%, 3 years 80% and 4 years 75%. Pathological findings in these patients showed varying degrees of small vessel thickening and occlusion together with degeneration, necrosis in the center of tumor and loss of tumor cells at periphery. CONCLUSIONS: Gamma knife is not adequately reliable for the control of hemangioblastoma cysts, it is an effective treatment of small or medium-size solid tumors, but long-term follow-up is needed. The recommended dose is 16 to 20 Gy.

Adolescent↗

PubMed2003

[Evaluation of noninvasive positive pressure ventilation in treatment for patients with severe acute respiratory syndrome].

OBJECTIVE: To analyze the effects of noninvasive positive pressure ventilation (NIPPV) on oxygenation of severe acute respiratory syndrome (SARS) patients, and to discuss the timing point for mechanical ventilation. METHODS: Twenty-five SARS patients with respiratory dysfunction treated with NIPPV were studied retrospectively in order to evaluate the influences within 24 hours after initiation of ventilatory support on their physiological indices and oxygenation. Patients with SARS were divided into two groups: survivor group (n=13) and non-survivor group (n=12). We compared the acute physiology and chronic health evaluation (APACHEII) score, respiratory rate (RR),saturation of oxygen (SpO(2)) and modificative respiratory index (MRI) for the survivors and non-survivors before NIPPV and after NIPPV for twenty-four hours, respectively. RESULTS: Although NIPPV administered via full-face masks might be an effective treatment for rapidly improving vital signs and gas exchange and sense of dyspnea in both groups during the initial 24 hours of ventilatory support, the patients in non-survivor group had higher APACHEII score, respiratory rates and lower SpO(2), MRI than the patients in survivor group (P<0.05) at the same intervals after initiation of support. CONCLUSION: Noninvasive ventilation should be used as a substitutive tool for endotracheal intubation an alternative treatment for acute respiratory failure related to SARS. Therefore, we should make efforts to avoid missing the time point for NIPPV or intubation, and we should not be restricted to the available indications for NIPPV or IPPV.

Adult↗

PubMed2003

Combination of balanced ultrafiltration with modified ultrafiltration attenuates pulmonary injury in patients undergoing open heart surgery.

OBJECTIVE: To explore the effects of ultrafiltration technique in preventing and relieving pulmonary injury in children undergoing open heart surgery and cardiopulmonary bypass (CPB). METHODS: Thirty cases with congenital heart defects were divided into a control group and an experimental group. In the control group, conventional cardiopulmonary bypass was used without ultrafiltration; while in the experimental group, cardiopulmonary bypass with balanced ultrafiltration and modified ultrafiltration were used. Pulmonary static compliance (Cstat), airway resistance (Raw), alveolar-arterial oxygen difference (A-a DO2), hematocrit (HCT), serum albumin (Alb), interleukin-6 (IL-6), endothelia-1 (ET-1) and thromboxane (TXB2) were measured. RESULTS: The pulmonary function was improved, HCT and serum albumin concentrations were increased, and some harmful medium-size solutes were decreased in the experimental groups compared with the control group. CONCLUSIONS: Combination of balanced ultrafiltration with modified ultrafiltration can effectively concentrate blood, exclude harmful inflammatory mediators, and attenuate lung edema and inflammatory responsive pulmonary injury.

Cardiac Surgical Procedures↗

PubMed2003

Kimura disease.

Explore the source record for details and available documents.

Angiolymphoid Hyperplasia with Eosinophilia↗

PubMed2003

Hypertonic perfusion reduced myocardial injury during subsequent ischemia and reperfusion in normal and hypertensive rats.

AIM: To determine the effects of hypertonic solution on myocardial ischemia and reperfusion injury in normal and stroke-prone hypertensive rat hearts in vitro. METHODS: Hearts were perfused in an isolated-perfused Langendorff apparatus and perfused with normal or hypertonic solution (360 mOsm/L, by addition of NaCl to the normal perfusate of 300 mOsm/L) before subjected to 30 min ischemia followed by 40 min isotonic reperfusion. Heart function, myocardial creatine kinase leakage, norepinephrine release, and ventricular calcium content were determined. RESULTS: Normal rat hearts with hypertonic perfusion showed higher recovery rate of spontaneous beating than control hearts after ischemia. Hypertensive rat hearts perfused with hypertonic solution also had better recovery in diastolic function and less creatine kinase leakage than hypertensive controls. Concomitantly, myocardial release of norepinephrine was also reduced from hypertensive hearts perfused with hypertonic solution. There was no significant difference in myocardial calcium content between normal and hypertonic perfused hypertensive hearts. CONCLUSION: Hypertonic perfusion may precondition the hearts and protect them from ischemia and reperfusion injury in both normal and hypertensive rats. The modulation of hypertonic perfusion on myocardial norepinephrine release and its role in cardioprotection needs further investigation.

Animals↗

PubMed2003

[Determination of schisandrin in shengmaiyin by HPLC].

OBJECTIVE: To determine the concentration of schisandrin in Shengmaiyin with HPLC. METHOD: The sample was extracted with ethyl acetate through supersonic wave. The solution was filtrated and evaporated. The residue was resolved with methanol and determined by HPLC using PHENOMENEX C18 (4.6 mm x 250 mm, 5 microns) chromatographic column, methanol-acetonitrile-water (15:15:10) as mobile phase. The wavelength for detection was 254 nm. RESULT: The peak of schizandrin appears on about 7.10 minutes. The standard curves of schizandrin were linear in the concentration range of 0.2-2.0 micrograms, r = 0.9996. The average recovery of schizandrin were 100.5% (RSD 2.84%). CONCLUSION: This method was found to be sensitive, quick and accurate for the measurement of schizandrin concentrations in Shengmaiyin.

Administration, Oral↗

PubMed2003

[Polymorphisms of insulin-like growth factor binding protein 3 gene and its associations with several carcass traits in Qinchuan cattle].

DNA samples from 60 Qinchuan cattle (Bos taurus) were analyzed with PCR-RFLPs and sequencing for insulin-like growth factor binding protein 3 (IGFBP3) gene. Fragments of 651 bp were amplified with two primers and the products of PCR were digested with restriction endonuclease HaeIII. The produced fragments showed three genotypes, namely AA,AB and BB after electrophoresis. Frequencies of the genotype AA,AB,BB and allele A,B were 0.7,0.28,0.02,and 0.84,0.16,respectively. Sequence analysis showed that a transversion of C-->A at 299 nt resulted in loss of the cleaved site of restriction endonuclease HaeIII and produced this polymorphism. This polymorphic locus of IGFBP3 gene was at Hardy-Weinberg equilibrium (P>0.05). The genotypes of AA,AB,BB slightly affected several slaughter and carcass traits of Qinchuan cattle. Dressing percentage,net meat percentage, striplion percentage, tenderloin percentage, ribeye percentage and tender shoulder percentage were decreased with the genotypes of AA,AB and BB in Qinchuan cattle, but it was not significant (P>0.05). Average ribeye area in individuals of AA genotype was significantly higher than that in individuals of BB genotype (P<0.05), and beef fat content in individuals of genotype AB and BB was significantly higher than that in individuals of AA genotype (P<0.01).

English Abstract↗

PubMed2002

Epigenetic regulation of a novel tumor suppressor gene (hDAB2IP) in prostate cancer cell lines.

hDAB2IP (human DAB2 (also known as DOC-2) interactive protein) is a novel GTPase-activating protein for modulating the Ras-mediated signal pathway. We demonstrate that the down-regulation of hDAB2IP mRNA in prostate cancer (PCa) cells is regulated by transcriptional levels. Analysis of the hDAB2IP promoter revealed that it is a typical TATA-less promoter containing many GC-rich sequences. In this study, we delineated the potential impact of the epigenetic control of the hDAB2IP promoter on its gene regulation in PCa. Acetylhistone H3 was associated with the hDAB2IP promoter, and CpG islands remained almost unmethylated in normal prostatic epithelia, but not in PCa cell lines. Our data further indicated that trichostatin A (histone deacetylase inhibitor) and 5'-aza-2'-deoxycytidine (DNA hypomethylation agent) acted cooperatively in modulating hDAB2IP gene expression in PCa, whereas histone acetylation played a more significant role in this event. Moreover, a core promoter sequence from the hDAB2IP gene responsible for these treatments was identified. We therefore conclude that epigenetic regulation plays a potential role in regulating hDAB2IP expression in PCa and that these results also provide a new therapeutic strategy for PCa patients.

Base Sequence↗

PubMed2002

Identification of P2Y12-dependent and -independent mechanisms of glycoprotein VI-mediated Rap1 activation in platelets.

Glycoprotein (GP) VI is a critical platelet collagen receptor, yet the steps involved in GPVI-mediated platelet activation remain incompletely understood. Because activation of Rap1, an abundant small guanosine triphosphatase (GTPase) in platelets, contributes to integrin alpha(IIb)beta(3) activation, we asked whether and how GPVI signaling activates Rap1 in platelets. Here we show that platelet Rap1 is robustly activated upon addition of convulxin, a GPVI-specific agonist. Using a reconstituted system in RBL-2H3 cells, we found that GPVI-mediated Rap1 activation is dependent on FcRgamma but independent of another platelet collagen receptor, alpha(2)beta(1). Interestingly, GPVI-mediated Rap1 activation in human platelets is largely dependent on adenosine diphosphate (ADP) signaling through the P2Y(12) and not the P2Y(1) receptor. However, experiments with specific ADP receptor antagonists and platelets from knockout mice deficient in P2Y(1) or the P2Y(12)-associated G-protein, Galphai(2), indicate that human and murine platelets also have a significant P2Y(12)-independent component of GPVI-mediated Rap1 activation. The P2Y(12)-independent component is dependent on phosphatidylinositol 3-kinase and is augmented by epinephrine-mediated signaling. P2Y(12)-dependent and -independent components are also observed in GPVI-mediated platelet aggregation, further supporting a role for Rap1 in aggregation. These results define mechanisms of GPVI-mediated platelet activation and implicate Rap1 as a key signaling protein in GPVI-induced platelet signaling.

Adenosine Diphosphate↗

PubMed2002

Genetic analysis of adipogenesis through peroxisome proliferator-activated receptor gamma isoforms.

Peroxisome proliferator-activated receptor (PPAR) gamma is a nuclear receptor that is a key regulator of adipogenesis and is present in two isoforms generated by alternative splicing, PPARgamma1 and PPARgamma2. Studies of the ability of each isoform to stimulate fat differentiation have yielded ambiguous results, in part because PPARgamma stimulates its own expression. We have thus undertaken a formal genetic analysis using PPARgamma-null fibroblast cell lines to assess the specific role of each individual isoform in adipogenesis. We show here that both PPARgamma1 and PPARgamma2 have the intrinsic ability to stimulate robust adipogenesis. Adipose cells stimulated by either PPARgamma1 or PPARgamma2 express a similar gene profile and show similar responses to insulin. However, in response to low ligand concentrations, PPARgamma2 shows a quantitatively greater ability to induce adipogenesis. Analyses involving coactivator binding and transcriptional assays indicate that PPARgamma2 has an enhanced ability to bind components of the DRIP/TRAP complex, coactivators required for fat differentiation.

Adipocytes↗

PubMed2002

Influence of soluble polymer polyvinylpyrrolidone on separation of small peptides and amino acids by microchip-based capillary electrophoresis.

In microchip-based capillary electrophoresis, the resolution and separation efficiency of small peptides and amino acids can be noticeably improved by adding a low molecular weight (30,000) soluble polymer additive, polyvinypyrrolidone in the separation medium. Several separation conditions such as injection time and electrophoretic buffer have been investigated and optimized. Using an electro-stacking scheme, the resolution and separation efficiency of small peptides and amino acids can be enhanced significantly. Under the optimal conditions, the separation of fluorescein isothiocyanate Isomer I-labeled small peptides and amino acids was successfully achieved within 100 s.

Amino Acids↗