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Biomedical subjects

Hong Chen

Publications and source records attributed to Hong Chen.

At least 73 records · Page 4Linked to original sources
PubMed2006

[Analysis of POU1F1 gene polymorphisms in Qinchuan cattle and Chinese Holstein cattle].

PCR-RFLP was applied to analyze the polymorphisms of POU1F1 gene in 218 Qinchuan cattle (QQ) and Chinese Holstein cattle (HC). Results demonstrated Hinf I polymorphisms in the 451 bp PCR product in the two populations. The frequencies of alleles A/B in QQ and HC populations were 0.232/0.768 and 0.132/0.868, respectively. The frequencies of three genotypes AA, AB and BB were 0.030/0.403/0.567 and 0.007/0.251/0.742, respectively. Qinchuan cattle population was at Hardy-Weinberg equilibrium at this locus, but Chinese Holstein cattle population was not. The gene heterozygosity/effective allele gene number/Shannon information entropy/polymorphism information content of Qinchuan cattle and Chinese Holstein cattle populations were listed for 0.356/1.553/0.541/0.292 and 0.229/1.297/0.390/0.203, respectively. All indices were higher in the Qinchuan cattle population.

Animals↗
PubMed2006

[Accelerated somatic cell senescence and changes in p16INK4a expression after exogenous DNA transfection].

During the transfection of mouse embryonic fibroblasts (MEF), we found these cells became senescent, appearing enlarged with hollow cytoplasm and multinucleated. The telomere lengths of these senescent MEFs were significantly shorter than primary untransfected MEFs. In senescent MEF cells, DNA methylation of p16INK4a 5'-regulatory region showed gradual reduction as cells aged. RT-PCR and Northern blot demonstrated that the expression of p16INK4a in transfected senescent cells was 12-16 times more than primary cells. The senescent transfected MEF cells as donors of nuclei could support the early development of cloned embryos after nuclear transfer.

Animals↗
PubMed2006

Dose-response study of spinal hyperbaric ropivacaine for cesarean section.

BACKGROUND: Spinal hyperbaric ropivacaine may produce more predictable and reliable anesthesia than plain ropivacaine for cesarean section. The dose-response relation for spinal hyperbaric ropivacaine is undetermined. This double-blind, randomized, dose-response study determined the ED50 (50% effective dose) and ED95 (95% effective dose) of spinal hyperbaric ropivacaine for cesarean section anesthesia. METHODS: Sixty parturients undergoing elective cesarean section delivery with use of combined spinal-epidural anesthesia were enrolled in this study. An epidural catheter was placed at the L1 approximately L2 vertebral interspace, then lumbar puncture was performed at the L3 approximately L4 vertebral interspace, and parturients were randomized to receive spinal hyperbaric ropivacaine in doses of 10.5 mg, 12 mg, 13.5 mg, or 15 mg in equal volumes of 3 ml. Sensory levels (pinprick) were assessed every 2.5 min until a T7 level was achieved and motor changes were assessed by modified Bromage Score. A dose was considered effective if an upper sensory level to pin prick of T7 or above was achieved and no intraoperative epidural supplement was required. ED50 and ED95 were determined with use of a logistic regression model. RESULTS: ED50 (95% confidence interval) of spinal hyperbaric ropivacaine was determined to be 10.37 (5.23 approximately 11.59) mg and ED95 (95% confidence interval) to be 15.39 (13.81approximately 23.59) mg. The maximum sensory block levels and the duration of motor block and the rate of hypotension, but not onset of anesthesia, were significantly related to the ropivacaine dose. CONCLUSION: The ED50 and ED95 of spinal hyperbaric ropivacaine for cesarean delivery under the conditions of this study were 10.37 mg and 15.39 mg, respectively. Ropivacaine is suitable for spinal anesthesia in cesarean delivery.

Adult↗
PubMed2006

[Morphological characteristics of craniofacial complex in adults with skeletal class III malocclusions].

OBJECTIVE: To identify the morphological characteristics of craniofacial structure in patients with skeletal class III malocclusions. METHODS: The study samples consisted of 63 lateral cephalometric radiographs of adult with class I malocclusion (32 male and 31 female, ages >17 years) and 27 patients with skeletal class III malocclusion (14 male and 13 female, ages >17 years, ANB >-3). The proportion of posterior cranial base and the mandibular length were measured. RESULT: There was an increase in total mandibular length (Go-Gn, Cd-Gn) in female patients with class III malocclusion. There was a decrease in the posterior cranial base length (S-Ar) and an increase in mandibular length (Go-Gn) in male patients with class III malocclusion. CONCLUSION: The major craniofacial characteristics of skeletal class III malocclusion compared with those of class I malocclusion are smaller posterior cranial base in males and larger mandibular length in both sexes.

Adolescent↗
PubMed2006

[A new method of molecular marker--RMAPD].

Random microsatellite amplify polymorphic DNA (RMAPD) is a new method of molecular marker. It can reveal genome DNA polymorphisms of organism only when random primer and microsatellite forward or reverse primer are combined together as a pair of primers by the PCR reaction system with Taq DNA polymerase, MgCl2, dNTPs and contemplate DNA. The core question of RMAPD is validity of the primers used. A lot of experiments of RMAPD in 69 Xinong Saanen dairy goats showed that RMAPD primers were effective. Comparison of RMAPD, microsatellite and RAPD markers demonstrated that RMAPD was different from each other in primers, amplification protocol and repetition. RMAPD is not equal to RAPD, but a extendable RAPD. Therefore, RMAPD is regarded as a new method of molecular marker. As it has many characteristics of DNA marker, RMAPD has a widest potential application in animal breeding and genetics, such as analysis of genetic structure and relationship and MAS.

Animals↗
PubMed2006

[Study on HPLC determination method and pharmacokinetics of tirapazaming in rabbits].

We have developed an HPLC method for the determination of tirapazaming (3-Amino-1,2,4-Benzotriazine -1,4-dioxide, TPZ) in rabbits and have studied the related pharmacokinetics in rabbits. After protein was precipitated, TPZ in plasma was determinated on HPLC with UV detection at 266 nm, and the mobile phase consisted of methyl alcohol and phosphoric buffer (10: 90, adjusted to pH6.5 +/- 0.1 with NaOH). TPZ and endogenous substances could be separated. Its calibration curve was linear (r=0.9995) within the range of 0.150-59. 98 mg/L, the detection limits was 0.5 ng (S/N>3), the recovery was more than 95% (n=3), the intra-day and inter-day precision was less than 6.0% (n = 5). The concentration-time curve of TPZ in rabbit plasma could be fitted to two-compartment model. These data indicate the method is sensitive, simple and reliabe. It is suitable for the pharmacokinetic study of TPZ in rabbits.

Animals↗
PubMed2006

[Genetic diversity of mitochondrial DNA D-loop sequences in cattle breeds in Guizhou].

The complete mitochondrial D-loop sequences, 910 bp in length, in 82 individual cattle from 4 breeds in Guizhou province were analyzed. The results revealed 31 mitochondrial haplotypes, 65 polymorphic sites, covering 7.14% of the entire length of the sequence. Among these polymorphic sites, there were 62 transitions, 2 transversions and 1 coexistent site of transition and transversion. The nucleotide diversity (pi value) and haplotype diversity (H) estimated from mtDNA D-loop region in 4 cattle breeds in Guizhou varied from 2.16%-2.61% and 0.695-0.909, respectively, showing that abundant mitochondrial genetic diversity exists in Guizhou cattle breeds. The Neighbor-Joining molecular phylogenetic tree of mtDNA D-loop of 4 Guizhou cattle breeds was constructed according to the 31 haplotypes. The NJ tree indicated that the origin of cattle breeds was from Bos taurus and Bos indicus which had nearly the same influence on cattle breeds in Guizhou. The feasibility of applying nucleotide diversity (pi value) to the evaluation of bovine genetic differentiation was discussed.

Animals↗
PubMed2006

Time-resolved fluorescence detection of mosaic DNA chip.

We demonstrated a time-resolved fluorescence (TRF) label and detection of mosaic DNA chip in this paper. We synthesized oligonucleotide sequences in situ on glass slides directly, and then sliced them up into small pieces and patched up the pieces bearing different sequences to generate a mosaic DNA chip. With multiple 4, 7-bis(chlorosulfophenyl)-1, 10-phenanthroline-2, 9-dicarboxylic acid (BCPDA, abbreviated as BCPDA) labeling method based on avidin-biotin amplification, we established a TRF detection format on the mosaic DNA chip. The detection method allows discriminatory signals for perfect match, one-base mismatch, two-base mismatch, and three-base mismatch by TRF labeled DNA hybridization, whereby Europium (III, Eu3+) was captured and released on the principle of complexation and dissociation interaction between BCPDA and Eu3+ solution when the BCPDA-tagged avidin and biotin-capped oligonucleotide sequence linked. The fluorescence spectra and related lifetimes were determined. We also compared the TRF detection mode with the conventional fluorescence one. These results showed the former is a potential alternative replacement of the latter, especially for labeling the mosaic DNA chip. The discovery is of fundamental interest and has significant implications to biochips and biosensors based on time-resolved-fluorescence detection.

Avidin↗
PubMed2006

Aberrant methylation of RASGRF2 and RASSF1A in human non-small cell lung cancer.

Aberrant methylation of promoter CpG that causes silencing of tumor suppressor genes (TSGs) may play a key role in the carcinogenesis of many cancer types. RASSF1A, regarded as a TSG, has been extensively studied in lung cancer and other malignant tumors, whereas RASGRF2 has only been reported to possibly play a role in the pathogenesis of pancreatic cancer cell lines. The aims of our study were to i) determine the methylation profile of RASGRF2 and ii) compare the methylation profiles of RASGRF2 with RASSF1A in lung cancer. We examined RASGRF2 expression by reverse transcription PCR and aberrant methylation of RASGRF2 by methylation-specific PCR in lung cancer cell lines. Loss of RASGRF2 expression was presented in 36% lung cancer cell lines while aberrant methylation of RASGRF2 was present in 30% (3/10) non-small cell lung cancer (NSCLC) cell lines and in 25% (1/4) small cell lung cancer (SCLC) cell lines. The concordance between loss of expression and aberrant methylation of RASGRF2 was 86% (12/14). RASGRF2 expression was restored after treatment with the demethylating agent, 5-aza-2'-deoxycytidine in all four cell lines tested that downregulated RASGRF2 expression. Among primary NSCLC, RASGRF2 and RASSF1A methylation was observed in 34% (39/114) and 39% (44/114) of cases respectively, while it was observed in only 7% (4/57) and none of the corresponding non-malignant lung tissue. There is no correlation between RASGRF2 and RASSF1A methylation status. Both RASGRF2 and RASSF1A methylation did not associate with clinical characteristics. Frequent methylation and silencing of RASGRF2 in tumor cells may play an important role, different from that of RASSF1A, in the carcinogenesis of NSCLC.

Aged↗
PubMed2006

[Repair of compound skin and bone defects in hands with pedicle osteocutaneous groin flap based on superficial circumflex iliac vessels].

OBJECTIVE: To investigate the outcome of repairing hand composite defects using pedicle osteocutaneous groin flap. METHODS: From February 1998 to May 2004, 33 cases of hand composite defects were repaired with pedicle osteocutaneous groin flap. There were 22 males and 11 females. The age was 19 to 54 years with an average of 24.3 years. The defect was caused by palmar penetrating injury in 17 cases, by dorsal hand crushing injury in 9 cases and by other injury in 7 cases. Twenty-three cases complicated by metacarpal defect, 10 by phalanx defect. The size of skin defect was 3. 5 cm X 2.0 cm to 15.0 cm X 10.0 cm, the size of bone defect was 1.5 to 3.5 cm. After 3 to 7 days of primary debridement, defect was repaired by the pedicle osteocutaneous groin flap based on the superficial circumflex iliac vessels. The flap size was 4.0 cm X 2.5 cm to 17.0 cm X 11.0 cm. RESULTS: All the osteocutaneous flaps survived. During the 4 to 22 months follow-up postoperatively, the texture, appearance and function of the flap were excellent and bone union was obtained in all cases after 7 to 9 weeks of operation. CONCLUSION: The pedicle osteocutaneous groin flap is an ideal flap to repair the composite defect of the hand, with the benefit of simple procedure and reliable blood supply.

Adult↗
PubMed2006

Oviposition behavior of female Anopheles gambiae in western Kenya inferred from microsatellite markers.

Anopheles gambiae females in a relatively isolated hut and all larvae from larval habitats within 100 m of the hut were collected in August 2001 in western Kenya. Among 42 aquatic habitats, 16 had A. gambiae larvae. Two hundred fifty larvae and 58 adults were genotyped using nine microsatellite markers to infer sibling relationship between the larvae and maternity between the females and larvae. The pairwise genetic relatedness of A. gambiae larvae per habitat ranged from -0.4112 to 0.9375, indicating that full siblings, half siblings, and genetically unrelated individuals presented at those habitats with multiple larvae. From a likelihood analysis, it was estimated that 56.6% of females had larvae in multiple habitats. These results substantiate that one A. gambiae female uses multiple breeding sites for oviposition, and thus, average genetic relatedness for breeding sites with high larval populations tends to be low.

Animals↗
PubMed2006

[The synthesis and function analysis of omega-3 fatty acid desaturase gene from Caenorhabditis briggssae].

Omega-3 polyunsaturated fatty acids (PUFAs) have been broadly investigated and shown to exert many preventive and therapeutic actions besides their important role in maintenances human health and normal development. In mammals, the level of omega-3 PUFAs is relatively too low compared with omega-6 PUFAs, which metabolically and functionally distinct from omega-3 PUFAs and often have important opposing physiological functions. Either the inefficiency of omega-3 PUFAs or the excess of omega-6 PUFAs will cause many healthy problems. So methods have been sought to increase the amount of omega-3 PUFAs and to improve the omega-6/omega-3 ratio in body. In this study, the sFat-1 gene, which putatively encodes a omega-3 fatty acid desaturase, was chemically synthesized according to the sequence from Caenorhabditis briggssae (with codon usage modified), and constructed into a mammal expression vector pcDNA3. 1-sFat1-EGFP. This vector was introduced into CHO cells by lipid-mediated transfection, and it's expression quickly and effectively elevated the cellular omega-3 PUFAs (from 18-carbon to 22-carbon) contents and dramatically improved the ratio of omega-6/omega-3 PUFAs. Cellular lipids extracts from stably selected cells were analyzed with GC-MS and the results showed that amount of total omega-6 PUFAs dropped from 48.97% (in GFP cells)to 35.29% (in sFat-1 cells), whereas the amount of total omega-3 PUFAs increased from 7.86% to 24.02%, respectively. The omega-6/omega-3 ratio also dropped from 6.23 to 1.47. These data demonstrates the Caenorhabditis briggssae omega-3 Fatty Acid Desaturase gene, sFat-1, was synthesized successfully and can produce omega-3 PUFAs by using the corresponding omega-6 PUFAs as substrates, which shows its potential for use in the production of omega-3 PUFAs in transgenic animals.

Animals↗
PubMed2006

[Study the safety and effectively of human thrombin after tonsillectomy].

OBJECTIVE: To evaluate the safety and effectively of human thrombin after tonsillectomy. METHOD: This was a prospective, randomized and controlled clinical trial. 80 cases of both tonsillectomies were divided into study group and control group. We evaluated the hemostatic role in study group: human thrombin has been insufflated locally in right side; physiological saline was in lift side. Observed the effects on the hemostatic time, hemorrhagic volume and hemorrhagic volume per square unit. RESULT: After two sides received different drugs in both tonsillectomies, in study group and control group, the average hemostatic time was (62.8 +/- 24.6) S and (94.7 +/- 36.9) S, the hemorrhagic volume was (4.9 +/- 6.7) g and (7.3 +/- 13.4) g, the hemorrhagic volume per square unit was (0.79 +/- 0.98) g/cm and (1.14 +/- 1.95) g x cm(-2), respectively. Two sides had the significant difference (P < 0.05). During the study, no adverse event was reported in two groups. The index of HBsAg, HIV, HCV and Syphilis in study group (10 cases) were not abnormalities after the thrombin had been insufflated 3 months. CONCLUSION: Human thrombin had the better hemostatic role and security on the hemorrhage of capillary of tonsillectomy wound.

Adolescent↗
PubMed2005

[Antiviral effects of dual-target antisense rna: an experimental study with hepatitis B virus transgenic mice].

OBJECTIVE: To investigate the curative effects of dual-target antisense RNA targeting the X and P regions in the genome of hepatitis B virus (HBV). METHODS: Retrovirus vector pLXSN was used to construct 4 kinds of recombinant vector plasmids expressing dual-target antisense RNA complementary to the X and P regions in the genome of HBV, namely, pLXSN-asX, pLXSN-asP, pLXSN-asXP, and pLXSN-seX. 48 HBV transgenic mice were randomly divided into 6 equal groups: pLXSN-asX group, pLXSN-asX group, pLXSN-asX group, pLXSN-asX group, and blank plasmid blank (pLXSN) group, to be injected into the caudal vein with corresponding plasmids thrice for every other day, and blank control group. Venous blood samples were collected before, 1 day and 3 days, and 2, 4, and 8 weeks after the injection to undergo detection of serum HBV DNA and HBsAg. Eight weeks later the mice were killed and immunohistochemistry was used t examine the HBsAg and HBcAg in the tissues. Pathological examination of the tissues was performed. RESULTS: The serum HBsAg concentrations 4 and 8 weeks after injection were significantly lower than that before injection in the.pLXSN-asX and pLXSN-asXP groups (all P <0.05) with an inhibition rate of 24% and 27% respectively. In comparison with that before injection, the HBV DNA expression level 2 weeks after injection was significantly lower in the pLXSN-asX group (P < 0.05) with an inhibition rate of 58%. In comparison with that before injection, the HBV DNA expression level 8 weeks after injection was significantly lower in the pLXSN-asP group (P <0.05) with an inhibition rate of 58%. In comparison with that before injection, the HBV DNA expression level in the pLXSN-asXP group showed 2 times of significant decrease 1 week and 8 weeks after injection (both P < 0.05) with the inhibition rates of 66% and 77% respectively. HBsAg and HBcAg were expressed in liver were significantly lower in the pLXSN-asX, pLXSN-asP, and pLXSN-asXP groups than in other groups (P < 0.05). No significant abnormality was found in the tissues in all groups. CONCLUSION: Dual-target antisense RNA targeting the X and P regions in the genome of HBV inhibits the replication and expression of HBV, significantly stronger than single-target antisense-RNA.

Animals↗
PubMed2005

A cost evaluation of the Georgia Stroke and Heart Attack Prevention Program.

INTRODUCTION: Hypertension is a leading cause of stroke, coronary artery disease, heart attack, and heart and kidney failure in the United States, all of which contribute to the rising costs of health care. The Georgia Stroke and Heart Attack Prevention Program is an education and direct service program for low-income patients with hypertension. This project evaluated the cost-effectiveness of the program compared with the following two alternative scenarios: no treatment for high blood pressure and the typical hypertension treatment received in the private sector nationwide (usual care). METHODS: We estimated the preventive treatment costs and number of adverse health events averted (hemorrhagic and ischemic stroke, heart disease, and kidney failure) associated with the Georgia Stroke and Heart Attack Prevention Program in two Georgia health districts. We used program cost and service usage data obtained from the Georgia Department of Human Resources and probabilities and costs of expected adverse events published in peer-reviewed sources. We compared program costs and number of expected adverse health events averted with those expected from 1) no preventive care and 2) usual care for high blood pressure. RESULTS: The Georgia Stroke and Heart Attack Prevention Program was less costly and resulted in better health outcomes than either no preventive care or usual care. Compared with no preventive care in the two districts, the program was estimated to result in 54% fewer expected adverse events; compared with usual care, the program was estimated to result in 46% fewer expected adverse events. Combining the costs of preventive treatment with the costs of expected adverse events, the Georgia Stroke and Heart Attack Prevention Program cost an average of 486 dollars per patient annually, compared with average annual costs of 534 dollars for no care and 624 dollars for usual care. CONCLUSION: Maintaining a publicly financed stroke and heart attack prevention program is more cost-effective and results in greater health benefits than other plausible scenarios. Because the benefits of this program accrue to both the state and federal governments through reduced Medicaid and indigent care expenditures, both the state and federal governments have a financial incentive to support the program.

Antihypertensive Agents↗
PubMed2005

Elevated levels of serum soluble Fas are associated with organ and tissue damage in systemic lupus erythematosus among Chinese.

The aims of the present study are to evaluate the difference of the levels of soluble Fas (sFas) antigen between patients with systemic lupus erythematosus (SLE) and healthy controls and to explore whether sFas has a role in either the disease activity or the organ damage in SLE. Serum levels of sFas were measured in 40 Chinese patients with SLE and 15 age-, gender-, and race-matched healthy controls using double antibody ELISA. SLEDAI scores for disease activity were determined. Data of organ and tissue damage was obtained from clinical records. Serum sFas levels were significantly increased in both more active (mean=8043.8 pg/ml, P<0.001) and less active SLE patients (mean=4820.2 pg/ml, P<0.001) comparing to the healthy controls (mean=3253.4 pg/ml). There was also a significant difference in serum sFas levels between the more active SLE patients and less active SLE patients (P=0.04). But, the levels of sFas didn't correlate with SLEDAI. There was a significant difference in the serum sFas levels between patients with and without CNS disease (mean=9582.6, 6634.5 pg/ml; P=0.007). The same was true when patients with and without renal disease (mean=10972.7, 6520.1 pg/ml; P=0.019), as well as serositis (mean=10385.3, 6709.1 pg/ml; P=0.005) were analyzed. sFas is elevated in sera of SLE patients, especially in patients with active SLE. The elevated levels of sFas in the sera of patients with SLE may be closely associated with damage to the kidneys, central nervous system and serosa. Serum sFas may serve as a predictor of some organ and tissue damage in SLE.

Adolescent↗
PubMed2005

Amino-acid limitation induces transcription from the human C/EBPbeta gene via an enhancer activity located downstream of the protein coding sequence.

For animals, dietary protein is critical for the nutrition of the organism and, at the cellular level, protein nutrition translates into amino acid availability. Amino acid deprivation triggers the AAR (amino acid response) pathway, which causes enhanced transcription from specific target genes. The present results show that C/EBPbeta (CCAAT/enhancer-binding protein beta) mRNA and protein content were increased following the deprivation of HepG2 human hepatoma cells of a single amino acid. Although there was a modest increase in mRNA half-life following histidine limitation, the primary mechanism for the elevated steady-state mRNA was increased transcription. Transient transfection documented that C/EBPbeta genomic fragments containing the 8451 bp 5' upstream of the transcription start site did not contain amino-acid-responsive elements. However, deletion analysis of the genomic region located 3' downstream of the protein coding sequence revealed that a 93 bp fragment contained an amino-acid-responsive activity that functioned as an enhancer. Exogenous expression of ATF4 (activating transcription factor 4), known to activate other genes through amino acid response elements, caused increased transcription from reporter constructs containing the C/EBPbeta enhancer in cells maintained in complete amino acid medium. Chromatin immunoprecipitation demonstrated that RNA polymerase II is bound at the C/EBPbeta promoter and at the 93 bp regulatory region in vivo, whereas ATF4 binds to the enhancer region only. Immediately following amino acid removal, the kinetics of binding for ATF4, ATF3, and C/EBPbeta itself to the 93 bp regulatory region were similar to those observed for the amino-acid-responsive asparagine synthetase gene. Collectively the findings show that expression of C/EBPbeta, which contributes to the regulation of amino-acid-responsive genes, is itself controlled by amino acid availability through transcription.

Activating Transcription Factor 4↗