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Biomedical subjects

Hao Chen

Publications and source records attributed to Hao Chen.

At least 91 records · Page 5Linked to original sources
PubMed2005

[Effect of recombinant plasmid of Helicobacter pylori ureB gene on gastric epithelial cell].

To investigate the effect of recombinant plasmid of Helicobacter pylori ureB gene on gastric epithelial cell. The full length sequence of ureB gene from NCTC11637 was amplified by PCR. The recombinant plasmid was constructed by cloning the open reading frame (ORF) of ureB into the eukaryotic expression vector pcDNA3.1, and was transfected SGC-7901 cells, then the clones resisting Hygromycin were screened. mRNA expression of ureB of transfected cells was detected by RT-PCR. The effect of recombinant plasmid of Hp ureB gene on cell phenotype was observed by fluorescence strain, on proliferation by MTT, on apoptosis and cell cycles by flow cytometry, respectively. The positive clones of ureB (SureB) appeared cell membrane budding and cell shrinkage. MTT assay showed there was no statistic significance between the SureB and SpcDNA3.1 which were transfected only by pcDNA3.1 (P > 0.05), suggesting that the growth of SureB were not inhibited. The apoptosis rate of SureB was higher than that of SpcDNA3.1 (P = 0.007). Analysis for cell cycle showed that in SureB cells the proportion of S phase increased, the proportion of both G2/M and G0/G1 phase decreased. Positive transfection of ureB gene into SGC-7901 can change cell phenotype and induce cell apoptosis.

Apoptosis↗
PubMed2005

[Differentiation of mesenchymal stem cells into cardio myogenic cells under the induction of myocardial cell lysate].

OBJECTIVE: In order to understand the effects of cardiac microenvironment on the differentiation of bone marrow mesenchymal stem cells (MSCs) into myocardial-like cells, we simulated the cardiac microenvironment in vitro by adding myocardial cell lysate into the culture system of MSCs, and compared the differentiation promoting effect of myocardial cell lysate with that of well-established inducer 5-azacytidine (5-aza). METHODS: Myocardial cells isolated from newly born rats were lysed by repeat freezing and defrosting. MSCs isolated from adult rat were cultured in four different systems. Medium A: medium with myocardial cell lysate; medium B: medium with 5-aza; medium C: medium with 5-aza and myocardial cell lysate; and control medium: ordinary medium without any addition reagent. The dynamic changes of MSCs morphology in different media were observed within 7 days after introduction of MSCs. Immunohistochemical staining against alpha-actin, cTnT, Connexin43 and CD31 were performed at the end of cultivation. RESULTS: MSCs in both medium A and B were differentiated into myocardial-like cells expressing alpha-actin and cTnT after 7-day cultivation. Cells in medium A developed more myofilaments than those in medium B, and expressed CD31, whereas cells in medium B did not. MSCs in control medium only expressed alpha-actin. CONCLUSIONS: Myocardial cell lysate is an ideal inducer to differentiate MSCs into myocardial-like cells in vitro. The differentiation promoting effect of myocardial cell lysate is more predominant than that of 5-aza.

Animals↗
PubMed2005

[Comparative analysis of internal repeating segments in proteins of species from the three kingdoms of life].

In 1970's, Ohno proposed that primordial proteins might evolve from periodic amplification of oligopeptides. Internal repeating segments in proteins may play important roles in functional evolution of proteins. In this study,a new method was designed to extract internal repeating segments from proteomes of 8 modern species belong to eukaryota, bacteria and archaea, respectively. The repeating patterns and the frequencies within proteomes of each kingdom were analyzed by matrix plot. Simple repeat segments were found in eukaryotic proteins with high frequencies,but were much lower in bacteria and none in archaea. Further analysis showed that, the biased usage of amino acids in the internal repeating segments was positively related to the frequencies of individual amino acids in the proteome of a given species. The correlation coefficient was up to 0.95 in prokaryota, with the eukaryota to be lower. The high frequency of simple repeat sequences in eukaryotic proteomes, as well as the disparate relationships of amino acid compositions between the internal repeating segments and their haboring eukaryotic proteomes imply that the fast evolution of simple repeat sequences could be one force that generates the high complexity of eukarytic proteomes.

Animals↗
PubMed2005

[Comparison of curative effect of arthroscopic and open surgeries for retrograde intramedullary interlocking nails for femoral supracondylar fracture].

OBJECTIVE: To compare the curative effect of arthroscopic and open surgeries for retrograde intramedullary interlocking nails(RIIN) in the treatment of femoral supracondylar fracture. METHODS: A total of 40 patients with femoral supracondylar fracture underwent either arthroscopic (n=20) or open surgeries (n=20) for rRIIN. RESULTS: The operation time, surgical blood loss and bone union time in arthroscopic group was less than that in the open surgery group (P<0.05). Follow-up of the patients for 10.3+/-3.6 months revealed excellent results in 15 cases, good in 3 cases, and acceptable in 1 case in the arthroscopic group, according to the Kolmert criteria, while excellent in 7, good in 14, acceptable in 4 and poor in 2 cases in the open surgery group, without statistically significances in the rate of good or excellent outcomes between the two groups (90.0% vs 75.0%, P=0.246). CONCLUSION: Compared with open surgery, RIIN shortens the operation time, reduces intraoperative blood loss and accelerates bone union, thus benefiting the recovery of knee joint functions.

Adult↗
PubMed2005

[Effects of ionic strength on the flocculation and removal of cyanobacterial cells of Microcystis aeruginosa by clays].

The effect of ionic strength on the flocculation and removal of Microcystis aeruginosa by clays and chitosan-modified clays were studied. High ionic strength was beneficial to the removal of algae cells by clays due to the reduction of the thickness of electrical double layer that enhanced the collision probability of the granules. In contrast to normal clays, chitosan-modified clays showed a higher removal efficiency of Microcystis aeruginosa cells under low ionic strength. The removal efficiency was reduced from more than 90% to 70% by sepiolite, but promoted from 70% to 95% by modified sepiolite when the ionic strength decreased from 0.17mol/L to 0 mol/L. This is because the repulsion of positive charged groups in chitosan molecule chain were shielded by large number of ions at higher ionic strength that reduce the extensibility of the chitosan molecule, leading to the reduction of bridging and netting between particles. Chitosan-modified clays were therefore suitable for removal cyanobacterial cells in fresh waters such as lakes, reservoirs and rivers.

Adsorption↗
PubMed2005

[Evaluating the harmfulness of copper in aquatic environment by measuring the supercoiled structure change of plasmid DNA].

The interaction of cupric ions with supercoiled DNA was investigated by agarose gel electrophoresis. Experimental results indicate that cupric ions could convert DNA structure from supercoiled to relaxed forms outside the cells in distilled water medium. At the levels of 10(-3) mol/L and 10(-4) mol/L copper, supercoiled DNA was totally converted into other forms of DNA after 24 hours. At a lower cupric level of 10(-6) mol/L, 52% supercoiled DNA was converted to other forms after 24 h and the relaxed form increased by 17% at 48h. Supercoiled form of DNA relaxed and gradually disappeared with the increase of incubation period of copper ions with the plasmid DNA. Supercoiled DNA degraded into other forms more rapidly at higher copper concentration. The percentages of different forms of DNA were related to copper concentration and incubation time. These results suggested that changes in supercoiled DNA structure may provide a rapid and sensitive method to assess the harmfulness of copper in aquatic environment.

Copper↗
PubMed2005

[Changes of serum soluble P-selectin and tumor necrotic factor-alpha in patients with CMV induced acute coronary syndrome].

OBJECTIVE: To explore the changes and relationship between serum soluble P-selectin, tumor necrosis factor-alpha (TNF-alpha) in coronary heart disease patients with acute coronary syndrome (ACS) and human cytomegalovirus (HCMV) infection. METHODS: The levels of circulating soluble P-selectin, TNF-alpha, HCMV-IgM and HCMV-IgG were determined by enzyme-linked immunosorbent assay (ELISA) in 79 cases for ACS group, 30 cases for stable angina (SA) group and 30 healthy control cases. RESULTS: (1) The serum positive rate of HCMV-IgM and HCMV-IgG in the ACS, SA and healthy control groups were 30.4% (24/79), 10.0% (3/30) and 6.7% (2/30); 86.1% (68/79), 80.0% (24/30) and 53.3% (16/30), respectively. Positive rate of HCMV-IgM in the ACS was higher than those in SA and healthy control groups (P < 0.01), positive rate of HCMV-IgG in the ACS and SA groups were higher than that of the healthy control group (P < 0.01). (2) Compared with the SA group and healthy control group, the levels of the serum soluble P-selectin and TNF-alpha were significantly higher in patients with ACS [(6437.3 +/- 666.9) pg/ml vs. (1520.0 +/- 112.7) pg/ml and (1481.0 +/- 109.1) pg/ml, (56.2 +/- 18.4) pg/ml vs. (27.3 +/- 13.7) pg/ml and (28.1 +/- 11.3) pg/ml], respectively, P < 0.01). The AMI group, compared with the UA group in the ACS group, had significantly higher levels of the serum soluble P-selectin and TNF-alpha (P < 0.01). Compared with the SA group, the levels of the serum soluble P-selectin and TNF-alpha were not significantly different in healthy control group. (3) The levels of the serum soluble P-selectin and TNF-alpha in HCMV-IgM positive patients were significantly higher than the HCMV-IgM negative patients in the ACS group (P < 0.01). CONCLUSION: The chronic infection with HCMV might injure endothelial cells that subsequently contribute to the formation and progression of atherosclerosis, the acute infection with HCMV may induce increased serum levels of soluble P-selectin and TNF-alpha that might participate in acute coronary events.

Acute Coronary Syndrome↗
PubMed2005

[Sensitivity and specificity of granzyme B and perforin in diagnosing acute rejection after liver transplantation].

OBJECTIVE: To study the roles of granzyme B and perforin in diagnosing acute rejection after liver transplantation, and the relationship between their activity index (AI) and Banff's histological grading criteria. METHODS: Liver biopsies were processed as for routine surgical specimens and labeled with granzyme B and perforin monoclonal antibodies. The number of positive cells/mm(2) was determined as activity index (AI) by IPP image analysis software. Histologic findings were used as the "gold standard" in diagnosing acute rejection. RESULTS: Of 41 liver biopsy samples studied, acute rejection was noted in 21 cases, the remaining 20 cases showed no evidence of rejection. The AI of granzyme B and perforin in the acute rejection group was significantly higher than that in the non-acute rejection group (< 0.001). In the acute rejection group, the AI in moderate to severe acute rejection was higher than that in mild to indeterminate acute rejection (< 0.001). Compared with the "golden" histologic criteria, the sensitivity, specificity, positive predictive value, negative predictive value and accuracy of granzyme B in diagnosing acute rejection were 90.0%, 95.2%, 94.7%, 90.9% and 92.7% respectively. The values of these parameters for perforin were also above 80%. CONCLUSIONS: Granzyme B and perforin are key markers of activated immune cells in acute rejection and highly expressed during acute liver rejection episodes. As ancillary investigations, these parameters demonstrated high sensitivity and specificity in diagnosing acute rejection in allograft post-transplant liver biopsies.

Biomarkers↗
PubMed2005

[An automatic fluorescence chemosensitivity analysis system for tumors].

The Automatic Fluorescence Chemosensitivity Analysis System (AFCAS), on the basis of image analysis, image recognition and database technologies, automatically collects the microscopic fluorescent images, inputs patient information, processes images, counts cell number, analyzes statistical data, saves and screens the reports and thus it is able to provide effective informations for assisting medical diagnosis and treatments of tumors or cancers. The AFCAS System adopts the image recognition technology of Region Chain Code and Bayesian Classification and ADO-Based database technology.

Algorithms↗
PubMed2005

[Preconcentration with crosslinked chitosan for determination of trace manganese in waters by flame atomic absorption spectrometry].

A novel method for the preconcentration with crosslinked chitosan (CCTS) and determination of trace manganese in waters by flame atomic absorption spectrometry has been presented. The absorption rate of manganese (VII) by CCTS was 98% at pH 3.00. The effect of preconcentration time, dosage of CCTS, temperature, sample volume and co-existing elements have been investigated. The mechanism of adsorption of CCTS for Mn(VII) was also discussed. The detection limit of the method was 1.86 microg x L(-1), and the relative standard deviation (RSD) was 2.0% (n = 10). The method has been applied to the determination of trace manganese in south lake and Changjiang water with satisfactory results.

Chitosan↗
PubMed2005

[Study on the descriptive epidemiology of pregnancy-induced hypertension from 1995 - 2000 in Jiaxing of Zhejiang province, China].

OBJECTIVE: To describe the epidemiological characters of pregnancy-induced hypertension (PIH) in Jiaxing areas of Zhejiang province of China between 1995 and 2000. METHODS: We analyzed the perinatal health surveillance data that was collected as part of the Sino-American cooperative project on neural tube defects prevention established in 1992. The study population consisted of 136 070 pregnant women with at least 20 weeks of gestational age. National diagnostic criteria were used to identify the cases which were divided into three subgroups: mild, moderate and severe. RESULTS: 15 127 cases were identified and the overall incidence rate of PIH was 11.1% (95% CI : 11.0% - 11.3%). Among all the cases, mild, moderate and severe PIH were accounted for 71.4%, 22.3% and 6.3%, respectively. The proportions of PIH cases that occurred in the second trimester, third trimester and during delivery appeared to be 4.2%, 34.4% and 61.4%, respectively. There was a significant fall in the trend of PIH occurrence every year, which dropped from 10.7% in 1995 to 8.6% in 2000 by 19.6%. More risk of PIH seemed to be related to those mothers living in the urban areas with age under 20 or above 35, being peasants and having little educational, having had multiple gestations, conceiving in spring/summer or delivering in winter or spring etc. Compared with the results of national survey in 1988, the incidence rate of PIH was higher by 18.1%, while the proportion of severe PIH was much lower by 68.8%. Although the incidence rates of PIH in urban and rural areas were somehow similar, the proportion of severe PIH in rural areas was much higher than that in urban areas. CONCLUSION: Overall incidence rate and distribution of PIH were reported. Compared with the results in 1988, incidence rate of PIH was much higher, particularly for mild cases.

Adult↗
PubMed2004

Rapid neurosecretory and cardiovascular response to osmotic stimulation in conscious mice.

Experiments were performed to evaluate the neuroendocrine and cardiovascular effects of osmotic stimulation in mice. Hypertonic saline (HS) was administered centrally or via the blood stream to conscious mice during measurement of blood pressure (BP), heart rate (HR) and plasma vasopressin (VP) and oxytocin (OT). A test of hypovolemia on VP secretion was also performed. Chronic carotid arterial cannulas were inserted for blood sampling, cardiovascular monitoring and vascular injections. Intracerebroventricular (ICV) cannulas were used for central injections. Vascular injection of HS (30 microl, 3.4 M NaCl) caused rapid and transient increases in plasma VP and OT. Plasma VP increased from 5.6 +/- 0.9 to 10.0 +/- 1.0 pg/ml, while plasma OT increased from 1.5 +/- 0.6 to 8.6 +/- 2.4 pg/ml at the earliest time point, immediately after ICV injection. ICV osmotic stimulation produced a rapid and sustained increase in plasma VP, with no change in OT. Plasma VP levels were increased from basal levels of 5.1 +/- 1.5 to 13.1 +/- 4.6, 11.4 +/- 1.5, 12.6 +/- 1.7 pg/ml at 0, 1 and 5 min after injection, respectively. ICV HS also increased plasma corticosterone. BP was increased by both vascular and central osmotic stimulation. Vascular HS increased BP immediately (Delta15.3 +/- 1.7 mm Hg, 0 min) and transiently (Delta-3.9 +/- 4.6 mm Hg, 5 min) while central HS produced a sustained increase in BP (Delta10 +/- 1.4 and Delta9.8 +/- 1.9 mm Hg, 0 and 5 min). Osmotic stimulation produced no significant changes in HR. Acute hemorrhage (approximately 10% decrease in blood volume) increased plasma VP (4.9 +/- 1.0 vs. 8.4 +/- 2.2 pg/ml). These results show the pattern of endocrine and cardiovascular responses to osmotic stimulation in conscious mice. They demonstrate that (1) there are extremely rapid changes in plasma VP and OT; (2) plasma OT is increased only after peripheral vascular hypertonic injection, and (3) central and peripheral osmotic stimulations are associated with pressor responses.

Analysis of Variance↗
PubMed2004

Apoptosis pathway of liver cells in chronic hepatitis.

AIM: To study the pathway of apoptosis in chronic liver disease and the role of mitochondria in programmed cell death. METHODS: Liver biopsy specimens from 72 cases of chronic hepatitis and 29 cases of post hepatitis cirrhosis were studied. The pro-apoptotic protein Fas, FasL, Bax and the anti-apoptotic protein Bcl-2, Bcl-x(L), Bcl-2 alpha were studied immunohistochemically by SP method. Specimens from 15 cases of chronic hepatitis and post hepatitis cirrhosis were examined for their ultramicrostructures with special attention to their mitochondrial changes. Specimens from 3 normal adults (demised in traffic accidents) were used as control. RESULTS: The expression of proapoptotic proteins (Fas, FasL, Bax) in hepatocytes was significantly higher in the chronic hepatitis group than in the cirrhosis group (P<0.001). In the study of ultramicrostructure 364 hepatocytes were examined, from 12 cases of chronic hepatitis (including 10 mild cases, 1 moderate case and 1 severe case). Out of 364 hepatocytes 40 (11.0%) hepatocytes were found with various kinds of destruction in their mitochondria. Rupture of the outer membrane of mitochondria and the leakage of matrix from the intermembrane space were definitely demonstrated. The ultramicrostructural changes of mitochondria in the chronic hepatitis group were statistically higher than that in normal adults control group (chi(2)=4.32, P<0.05). CONCLUSION: The result of the study was in support of the current view that the apoptotic process in chronic hepatitis patients were largely along the intrinsic pathway (mitochondrial pathway), given that the intrinsic and extrinsic pathways could interlinked (converged) at some point on their progression, also it is impossible at present to exclude the possibility that the two pathways could be chosen by hepatocytes in parallel simultaneously.

Apoptosis↗
PubMed2004

BMP receptor signaling is required for postnatal maintenance of articular cartilage.

Articular cartilage plays an essential role in health and mobility, but is frequently damaged or lost in millions of people that develop arthritis. The molecular mechanisms that create and maintain this thin layer of cartilage that covers the surface of bones in joint regions are poorly understood, in part because tools to manipulate gene expression specifically in this tissue have not been available. Here we use regulatory information from the mouse Gdf5 gene (a bone morphogenetic protein [BMP] family member) to develop new mouse lines that can be used to either activate or inactivate genes specifically in developing joints. Expression of Cre recombinase from Gdf5 bacterial artificial chromosome clones leads to specific activation or inactivation of floxed target genes in developing joints, including early joint interzones, adult articular cartilage, and the joint capsule. We have used this system to test the role of BMP receptor signaling in joint development. Mice with null mutations in Bmpr1a are known to die early in embryogenesis with multiple defects. However, combining a floxed Bmpr1a allele with the Gdf5-Cre driver bypasses this embryonic lethality, and leads to birth and postnatal development of mice missing the Bmpr1a gene in articular regions. Most joints in the body form normally in the absence of Bmpr1a receptor function. However, articular cartilage within the joints gradually wears away in receptor-deficient mice after birth in a process resembling human osteoarthritis. Gdf5-Cre mice provide a general system that can be used to test the role of genes in articular regions. BMP receptor signaling is required not only for early development and creation of multiple tissues, but also for ongoing maintenance of articular cartilage after birth. Genetic variation in the strength of BMP receptor signaling may be an important risk factor in human osteoarthritis, and treatments that mimic or augment BMP receptor signaling should be investigated as a possible therapeutic strategy for maintaining the health of joint linings.

Alleles↗
PubMed2004

Content-rich biological network constructed by mining PubMed abstracts.

BACKGROUND: The integration of the rapidly expanding corpus of information about the genome, transcriptome, and proteome, engendered by powerful technological advances, such as microarrays, and the availability of genomic sequence from multiple species, challenges the grasp and comprehension of the scientific community. Despite the existence of text-mining methods that identify biological relationships based on the textual co-occurrence of gene/protein terms or similarities in abstract texts, knowledge of the underlying molecular connections on a large scale, which is prerequisite to understanding novel biological processes, lags far behind the accumulation of data. While computationally efficient, the co-occurrence-based approaches fail to characterize (e.g., inhibition or stimulation, directionality) biological interactions. Programs with natural language processing (NLP) capability have been created to address these limitations, however, they are in general not readily accessible to the public. RESULTS: We present a NLP-based text-mining approach, Chilibot, which constructs content-rich relationship networks among biological concepts, genes, proteins, or drugs. Amongst its features, suggestions for new hypotheses can be generated. Lastly, we provide evidence that the connectivity of molecular networks extracted from the biological literature follows the power-law distribution, indicating scale-free topologies consistent with the results of previous experimental analyses. CONCLUSIONS: Chilibot distills scientific relationships from knowledge available throughout a wide range of biological domains and presents these in a content-rich graphical format, thus integrating general biomedical knowledge with the specialized knowledge and interests of the user. Chilibot http://www.chilibot.net can be accessed free of charge to academic users.

Biology↗
PubMed2004

[Orthotopic heart transplantation: clinical experience on 56 patients].

OBJECTIVE: To summarize the clinical experience on 56 patients undergoing orthotopic heart transplantation. METHODS: Between May 2000 and December 2003 56 patients, 47 with cardiomyopathy, 2 with end-stage valvular heart disease, 2 with end-stage ischemic heart disease, 2 with primary malignant cardiac tumor, 1 with complicated congenital heart disease, 1 with muscular dystrophy cardiomyopathy, and 1 with refractory malignant ventricular arrhythmias, underwent orthotopic heart transplantation in the Transplantation Center of Fudan University. The operative procedures included 19 conventional Stanford orthotopic cardiac transplantation in 19 cases and bicaval anastomotic cardiac transplantation in 37 cases. Postoperatively, the patients were prescribed with cyclosporine A + corticosteroids + MMF or FK506 + corticosteroids + MMF as anti-rejection therapy. RESULTS: One patient undergoing his fifth operation died of bleeding 3 days after operation. All survivors were followed-up for 12.4 months on average. Five patients died within 1 year postoperatively with a one-year survival rate of 91%. One patient died of allograft vasculopathy 38 months after operation. Other patients enjoyed heart function recovering to class I-II (NYHA). CONCLUSION: With proper recipient selection, excellent donor heart conservation, bicaval anastomotic technique, and efficient postoperative surveillance and treatment, heart transplantion may produce satisfying mid-term results.

Adolescent↗