Biomedical subjects

Hua Li

Publications and source records attributed to Hua Li.

At least 145 records · Page 8Linked to original sources

PubMed2003

[A study on proliferation of chondrocyte in callus during second fracture healing].

OBJECTIVE: To understand the regulation of chondrocyte proliferation in callus. METHODS: The histological structure of callus was observed and the percent of positive cells of Cylin D3, Cyclin E, Cyclin A, PCNA and BrdU in callus of 20 male SD rats were caculated in the fracture healing model by HE staining and immunohistochemical staining at 1, 2, 3 and 4 weeks after fracture. RESULTS: The callus under light microscope could be divided into four zones: resting zone(RZ), proliferating zone(PZ), mature zone(MZ) and hypertrophic zone(HZ). The arrangement of chondrocytes in callus was irregular and the boundary between the neighboring zones not as clear as on growth plate. The findings indicated that the proliferation and differentiation of the cells in cambium layer of periosteum and RZ played an important role during fracture healing in the first week; the proliferation of chondrocytes in PZ was very active in the second week, meanwhile the cells in cambium layer became quiet; the proliferating activity of chondrocytes in all these zones became declining and the chondrocytes came to be mature and hypertrophic gradually in the fourth week. CONCLUSION: The proliferating cells in the early stage of fracture healing should have supplied enough chondrocytes, after that time these cells would no longer proliferate; the skeletal repair would be carried out and be accompanied with the proceeding proliferation and differentiation of chondrocytes. After all, the proliferation of chondrocytes in callus is closely related to skeletal repair. Additional characters and elucidation of fracture healing will lay the foundation of subsequent studies aimed at identifying mechanisms for skeletal repair.

Animals↗

PubMed2003

[An applied anatomy study on bronchial artery and posterior intercostal artery].

OBJECTIVE: To provide anatomic data for clinical treatment of the right lung cancers at advanced or intermediate advanced stage. METHODS: One hundred and ninety eight adult cadavers were dissected and the data on the parameters for clinical reference were collected. RESULTS: It was found that the common trunks of the right bronchial artery and the third posterior intercostal artery can be divided into four types. The starting point of the common trunks of the right bronchial artery and the third posterior intercostal artery are level with the vertebrae from T2 to T8, and 70.20% of the common trunks' starting point are level with the vertebrae from T4 to T6. In addition, the average outer diameter of the third posterior intercostal artery at the midaxillary line is 0.78 mm +/- 0.33 mm. CONCLUSION: Base on the above anatomic data, we deem it a reliable and appropriate way to infuse drugs into the third posterior intercostal artery at the midaxillary line for treating the advanced or intermediate-stage right lung cancers.

Arteries↗

PubMed2003

[Using ultrasonically activated scalpels as major instrument for vessel dividing and bleeding control in minimally invasive video-assisted thyroidectomy].

OBJECTIVE: To establish new techniques on the control of vessel dividing and bleeding in minimally invasive video-assisted thyroid surgeries. METHODS: One hundred and seventy volunteer patients with nodular goiter, adenoma and Graves' disease consecutively received the endoscopic thyroid operation according to Miccoli's mode from April 2002 to June 2003. The approach was designed to use ultrasonically activated scalpels [Harmonic Scalpel (R), Johnson & Johnson, USA] as a major, suction-dissector or others as supplementary instruments during the whole process. During the operations, two methods, "sequenced dissect-coagulate-cut" and "pre-coagulation + interlaced cut-suck-coagulate-dissect", were employed and separately evaluated for their safety or efficacy. RESULTS: All of the procedures, except that 2 (their lesions were proven to be "cancer" by frozen section and need different treatment), were successfully completed. None of them were interrupted and converted to open surgery due to uncontrolled bleeding or severe postoperative hematoma. Branches of major thyroid vessels can be directly divided by ultrasonic scalpel without ligation or using hemoclips, supposing the technique of "sequenced dissect-coagulate-cut" method was strictly used. Bleeding during intra-gland dissection can be effectively controlled by the combined techniques of precoagulation of the vessels and the capsule vessel network near and around the incision, and then, by coordinating manipulation with a special multiple functional ultrasonic scalpel and a suction-dissector, supposing the technique of "interlaced cut-suck-coagulate-dissect" was properly employed. CONCLUSIONS: Using ultrasonic scalpels as major, suction-dissector or others as supplementary instruments, manipulating cooperatively during the whole process, can be an ideal fashion in the site of a narrow gasless working space via a small single incision in anterio-inferior neck. And this may dramatically simplify the manipulation, and hence greatly reduce the operative difficulty. The reforms resolved two key technique problems in Miccoli's endoscopic operation: vessel-dividing and bleeding-control, therefore, laying a sound basis for the clinical application of this special approach.

Adolescent↗

PubMed2003

[Effect of xue hanjing oral fluid on mice immunological function].

OBJECTIVE: To observe effect of Xue Hanjing oral fluid on mice immunological function. METHOD: The weight of thymus gland and spleen and the function of abdominal cavity macrophage were measured. Production of the hemolysin antibody, the immunoglobulin of blood serum and complement and the proliferation of T lymphocytes were observed respectively by means of microblood, immune-turbidimetry and MTT staining. RESULT: Xue Hanjing oral fluid could enhance index of the thymus gland and spleen and the phago-percent of abdominal cavity macrophage, increase the immunoglobulin of blood serum(IgG and IgM), and accelerate production of the hemolysin antibody and the proliferation of T lymphocytes. CONCLUSIONS: Xue Hanjing oral can reinforce immunological function in mice.

Adjuvants, Immunologic↗

PubMed2002

Evaluation of calibration data in capillary electrophoresis using artificial neural networks to increase precision of analysis.

Increase of precision in capillary electrophoresis can be achieved applying suitable markers and evaluating calibration curves and data analysis with artificial neural networks. They are able to account for errors in both x- and y-axes, nonlinear response of detector and non-linearity of calibration curves eventually. A comparison of the artificial neural networks approach with ordinary least-squares (OLS) and bivariate least-squares regression (BLS) was done. While OLS and BLS give similar results, the method proposed and tested in analysis of several pharmaceutical products yields lower prediction errors than traditional linear least-squares methods and the precision of analysis was found in the range 0.5-1.5% relative.

Calibration↗

PubMed2002

Recombinant multi-epitope vaccine induce predefined epitope-specific antibodies against HIV-1.

Monoclonal antibody 2F5 recognizing ELDKWA-epitope on HIV-1 gp41 has significant neutralization potency against 90% of the investigated viruses of African, Asia, American and European strains, but antibodies responses to ELDKWA-epitope in HIV-1 infected individuals were very low. Based on the epitope-vaccine strategy suggested by us, a recombinant glutathione S-transferase (GST) fusion protein (GST-MELDKWAGELDKWAGELDKWAVDIGPGRAFYGPGRAFYGPGRAFY) as vaccine antigen containing three repeats of neutralizing epitope ELDKWA on gp41 and GPGRAFY on gp120 was designed and expressed in Escherichia coli. After vaccination course, the recombinant multi-epitope vaccine could induce high levels of predefined multi-epitope-specific antibodies in mice. These antibodies in sera could bind to both neutralizing epitopes on gp41 peptide, V3 loop peptide and recombinant soluble gp41 (aa539-684) in ELISA assay (antisera dilution: 1:1,600-25,600), while normal sera did not. Moreover, these antibodies in sera could recognize the CHO-WT cells which expressed HIV-1 envelope glycoprotein on the cell surfaces, indicating that the predefined epitope-specific antibodies could recognize natural envelope protein of HIV-1 though these antibodies were induced by recombinant multi-epitope-vaccine. These experimental results suggested a possible way to develop recombinant multi-epitope vaccine inducing multi-antiviral activities against HIV-1.

AIDS Vaccines↗

PubMed2002

Locally disordered conformer of the hamster prion protein: a crucial intermediate to PrPSc?

A crucial step for transformation of the normal cellular isoform of the prion protein (PrP(C)) to the infectious prion protein (PrP(Sc)) is thought to entail a previously uncharacterized intermediate conformer, PrP*, which interacts with a template PrP(Sc) molecule in the conversion process. By carrying out (15)N-(1)H two-dimensional NMR measurements under variable pressure on Syrian hamster prion protein rPrP(90-231), we found a metastable conformer of PrP(C) coexisting at a population of approximately 1% at pH 5.2 and 30 degrees C, in which helices B and C are preferentially disordered. While the identity is still unproven, this observed metastable conformer is most logically PrP* or a closely related precursor. The structural characteristics of this metastable conformer are consistent with available immunological and pathological information about the prion protein.

Animals↗

PubMed2002

Decreased thermodynamic stability as a crucial factor for familial amyloidotic polyneuropathy.

A single mutation in the wild-type transthyretin (WT TTR) such as V30M causes a familial amyloidotic polyneuropathy disease. Comparison of the three-dimensional crystal structures of WT and V30M does not tell much about the reason. High-pressure NMR revealed that at neutral pH both WT and V30M exist as equilibrium between the native tetramer and the dissociated/unfolded monomer. The native tetramer is highly stable in WT (deltaG(0)=104 kJ/mol at 37 degrees C, pH 7.1), but the stability is significantly reduced in V30M (deltadeltaG(0)=-18 kJ/mol), increasing the fraction of the unfolded monomer by a 1000-fold. Significant reduction of thermodynamic stability of WT TTR by mutation could be a crucial factor for familial amyloidotic polyneuropathy.

Amyloid Neuropathies, Familial↗

PubMed2002

Genetic and biophysical basis of sudden unexplained nocturnal death syndrome (SUNDS), a disease allelic to Brugada syndrome.

Sudden unexplained nocturnal death syndrome (SUNDS), a disorder found in southeast Asia, is characterized by an abnormal electrocardiogram with ST-segment elevation in leads V1-V3 and sudden death due to ventricular fibrillation, identical to that seen in Brugada syndrome. We screened patients with SUNDS for mutations in SCN5A, the gene known to cause Brugada syndrome, as well as genes encoding ion channels associated with the long-QT syndrome. Ten families were enrolled, and screened for mutations using single-strand DNA conformation polymorphism analysis, denaturing high-performance liquid chromatography and DNA sequencing. Mutations were identified in SCN5A in three families. One mutation, R367H, lies in the first P segment of the pore-lining region between the DIS5 and DIS6 transmembrane segments of SCN5A. A second mutation, A735V, lies in the first transmembrane segment of domain II (DIIS1) close to the first extracellular loop between DIIS1 and DIIS2, whereas the third mutation, R1192Q, lies in domain III. Analysis of these mutations in Xenopus oocytes showed that the R367H mutant channel did not express any current and the likely effect of this mutation is to depress peak current due to the loss of one functional allele. The A735V mutant expressed currents with steady state activation voltage shifted to more positive potentials. The R1192Q mutation accelerated the inactivation of the sodium channel current. Both mutations resulted in reduced sodium channel current (I(Na)) at a time corresponding to the end of phase 1 of the action potential, as described previously in the Brugada syndrome. Based upon these observations we suggest that SUNDS and Brugada syndrome are phenotypically, genetically and functionally the same disorder.

Alleles↗

PubMed2002

Enhancement of the discriminative stimulus effects of phencyclidine by the tetracycline antibiotics doxycycline and minocycline in rats.

RATIONALE: Tetracycline antibiotics share some neuroprotective and CNS effects with N-methyl- D-aspartate (NMDA) receptor antagonists. OBJECTIVES: The acute effects of two tetracycline antibiotics were compared to those of the prototypic NMDA antagonist phencyclidine (PCP). METHODS: The effects of minocycline (10-56 mg/kg) and doxycycline (10-56 mg/kg) were evaluated in Sprague-Dawley rats trained to discriminate 2.0 mg/kg IP of PCP from saline under a fixed ratio schedule of food presentation. RESULTS: Even though minocycline and doxycycline did not substitute for PCP, pretreatment with 32 mg/kg of either drug produced leftward shifts in the PCP dose-response curve. The 32 mg/kg dose of minocycline also produced a leftward shift in the dose-response curve for dizocilpine (MK-801), another NMDA channel blocker, in the same subjects. CONCLUSIONS: Tetracycline antibiotics may interact either directly or indirectly with NMDA receptors. This suggests that they might be utilized in treatment of brain disorders in which NMDA receptor over-activation has been implicated.

Animals↗

PubMed2002

Quantitative analysis of chiral compounds from unresolved peaks in capillary electrophoresis using multivariate calibration with experimental design and artificial neural networks.

Quantitation of optical isomers can be achieved even from incompletely resolved peaks with a multivariate calibration applying a combination of experimental design and artificial neural networks (ANN). Using the proposed approach, method development can be more efficient and analysis time shortened while quantitation of optical isomers with acceptable precision (+/-1-3%) can be achieved.

Journal Article↗

PubMed2002

Novel mutations in domain I of SCN5A cause Brugada syndrome.

Brugada syndrome, an autosomal dominantly inherited form of ventricular fibrillation characterized by ST-segment elevation in leads V1-V3 and right bundle-branch block on surface electrocardiogram, is caused by mutations in the cardiac sodium channel gene SCN5A. Patients with Brugada syndrome were studied using single-strand conformation polymorphism analysis, denaturing high-performance liquid chromatography, and DNA sequencing of SCN5A. Mutations were identified in SCN5A in two families and one sporadic case. In one family, a missense mutation leading to a glycine to valine substitution (G351V) in the pore region between the DIS5 and DIS6 transmembrane segments was detected. Biophysical analysis demonstrated that this mutation caused significant current reduction. In the other family, a 20-bp deletion of the exon 5 splice acceptor site was identified; as exon 5 encodes part of the intracellular loop between DIS2 and DIS3, this portion of the channel is disrupted. In the sporadic patient, a missense mutation resulting in the substitution of lysine by glutamic acid (K126E) in the intracellular loop at the boundary with DIS1 was identified. These three new SCN5A mutations in Brugada syndrome patients are all located within domain I of SCN5A, a region not previously considered important in the development of ventricular arrhythmias.

Animals↗

PubMed2002

Compound heterozygous mutations in KvLQT1 cause Jervell and Lange-Nielsen syndrome.

Jervell and Lange-Nielsen syndrome (JLNS) is characterized by sensorineural deafness, QT prolongation, abnormal T waves, ventricular tachyarrhythmias, and autosomal recessive inheritance. Previously homozygous mutations in the potassium channel-encoding genes, KvLQT1 (alpha-subunit) and KCNE1 (beta-subunit), have been described in consanguineous families with JLNS. We screened two nonconsanguineous families with JLNS for mutations in KvLQT1, using single-strand conformation polymorphism analysis, denaturing high-performance liquid chromatography, and DNA sequencing. In one family, a missense mutation was identified in exon 6 of KvLQT1 on the maternal side, resulting in a glycine to aspartic acid substitution at codon 269 (G269D). The apparently normal father had an incompletely penetrant missense mutation in exon 3 of KvLQT1, introducing a premature stop codon at position 171. In the other family, a missense mutation resulting in the substitution of asparagine for aspartic acid at codon 202 (D202N) was identified in the mother and maternal grandmother, who had QTc prolongation (borderline in the mother), while the father and paternal grandfather, who were clinically normal, had a deletion of nucleotide 585, resulting in a frameshift and premature termination. In both families, the proband inherited both mutations. In this report we provide evidence that not only homozygous but also compound heterozygous mutations in KvLQT1 may cause JLNS in nonconsanguineous families. Incomplete penetrance in individuals with mutations appears to be frequent, indicating a higher prevalence of mutations than estimated previously. Interestingly, mutations resulting in truncation of the protein appear to be benign, with heterozygous carriers being asymptomatic.

Base Sequence↗

PubMed2002

Analysis of the coxsackievirus B-adenovirus receptor gene in patients with myocarditis or dilated cardiomyopathy.

Myocarditis and dilated cardiomyopathy (DCM) are common causes of morbidity and mortality in children and adults, most commonly due to infection with coxsackievirus B or adenovirus. Increased expression of the common human coxsackievirus B-adenovirus receptor (CAR) has been reported in patients with DCM. We investigated the CAR gene in patients with acquired or familial myocarditis/DCM for mutations/polymorphisms. Several polymorphisms or intronic substitutions, distant from the intron-exon boundaries, were identified but no mutations. Based upon these data it appears that CAR gene mutations are not a major host determinant in the development of myocarditis and DCM.

Adenoviridae↗

PubMed2002

Multivariate statistical analysis of clinicopathologic factors influencing survival of patients with bile duct carcinoma.

AIM: To evaluate the influence of various clinicopathologic factors on survival of patients with bile duct carcinoma after curative resection. METHODS: A retrospective analysis was made for 86 cases of bile duct carcinoma treated from January 1981 to September 1995. Fifteen clinicopathologic factors possibly influencing survival were selected. Independent variables were first analyzed by univariate methods. Survival for variable was estimated by the method of Kaplan and Meier. The variables that were statistically significant by univariate analysis were included in a multivariate analysis, which were confirmed using the Cox stepwise proportion hazard model with the help of SPSS 10.0 for Windows software. RESULTS: The overall cumulative survival rate was 72.6 % at 1 year, 32.4 % at 3 years, and 18.7 % at 5 years. The results of univariate analysis showed that the major significant prognostic factors influencing survival of these patients were histological type of lesion, lymph node metastasis, pancreatic invasion, duodenal invasion, perineural invasion, macroscopic vessel involvement, resected surgical margin and depth of cancer invasion (P=0.02, 0.02, 0.004, 0.005, 0.01, 0.43, 0.03 and 0.04). Age, sex, location of tumor, size of tumor, macroscopic type of lesions, hepatic metastasis, and hepatic invasion were not significantly associated with prognosis (P>0.05). Pancreatic invasion, perineural invasion and lymph node metastases were the three most important prognostic factors by multivariate analysis using the Cox proportional hazards model. CONCLUSION: Pancreatic invasion, perineural invasion and lymph node metastases are the most important prognostic factors for bile duct carcinoma after curative resection.

Adult↗

PubMed2002

Effect of retinoid kappa receptor alpha (RXRalpha) transfection on the proliferation and phenotype of rat hepatic stellate cells in vitro.

OBJECTIVE: To study the effect of retinoid kappa receptor alpha (RXRalpha) transfection plus treatment with the RXRalpha ligand, 9-cis-RA, on the proliferation and phenotype of platelet-derived growth factor (PDGF) activated hepatic stellate cells (HSCs). METHODS: PDGF activated rat hepatic stellate cells were transfected with eukaryotic expression vector pcDNA3.1- human RXRalpha, and confirmed by Western blot. Proliferation of transfected HSC was assayed by bromodeoxyuridine (BrdU) incorporation as well as MTT, and the phenotype (alpha-smooth muscle actin, desmin) was observed by immunocytochemistry with image analysis. RESULTS: Transfection of the RXRalpha gene and treatment with ligand 9-cis-RA of PDGF-activated HSCs extended the increased expression of RXRalpha protein for at least 168 hours. Cell proliferation and expressions of alpha- smooth muscle actin (alpha-SMA) and desmin were blocked, compared with groups of sham-transfected, PDGF-activated, no transfection, no ligand treatment, and irrelevant ligand treated HSCs. CONCLUSION: Transfection with the RXRalpha gene followed by 9-cis-RA ligand treatment will inhibit the proliferation and reverse the phenotype of activated HSC.

Animals↗

PubMed2002

Genetics and cardiac arrhythmias.

In this review, the up-to-date understanding of the molecular basis of primary ventricular arrhythmias is outlined. Two disorders have recently been well described at the molecular level, the long QT syndromes and Brugada syndrome, and we review the current scientific knowledge of each disease. Two other disorders, arrhythmogenic right ventricular dysplasia and Wolff-Parkinson-White syndrome, which are on the cusp of understanding, are also described.

Arrhythmias, Cardiac↗

PubMed2002

[Effect of RAR-beta transfection on the proliferation and phenotype of rat hepatic stellate cells].

OBJECTIVE: To study the effect of RAR-beta transfection plus treatment with the corresponding ligand ATRA on the proliferation and phenotype of platelet-derived growth factor (PDGF)-activated hepatic stellate cells (HSC). METHODS: PDGF-activated hepatic stellate cells of rats were transfected with eukaryotic expression vector pCMV-script-RAR-beta, which was verified by western blot. The proliferation of transfected HSC was assayed by BrdU incorporation as well as MTT methods. Their phenotype (alpha-SMA and desmin) was observed by immunocytochemistry assay with image analysis and RAR-beta protein expression was detected by western blot. RESULTS: Transfection of RAR-beta gene and treatment with ligand ATRA could increase the expression of RAR-beta protein for at least 144h and inhibit the proliferation and the expression of alpha-SMA and desmin in PDGF-activated HSC. Significant statistical differences were perceived comparing with sham-transfected, only-PDGF treated, non-ligand treated and irrelevant ligand-treated HSC. CONCLUSIONS: Transfected with RAR-beta gene as well as using related ligand ATRA could suppress the proliferation and reverse the activation phenotype of activated HSC.

Animals↗