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Biomedical subjects

J Ding

Publications and source records attributed to J Ding.

At least 163 records · Page 9Linked to original sources
PubMed1998

Study of hepatitis C virus genotype in Guizhou area of southwestern China.

OBJECTIVE: To determine the concordance in various hepatitis C (HCV) genotyping methods and to investigate the distribution of HCV genotypes in Guizhou area of Southwest China. METHODS: Serum samples from 206 patients (100 with chronic hepatitis and 106 with hemopathy) were detected for antibody of HCV by second generation enzyme-labelled immunosorbent assay (ELISA). Thirty-five anti-HCV positive samples were detected for HCV RNA by RT-polymerase chain reaction (PCR) and 30 HCV RNA positive samples were determined for their genotypes by three various genotyping methods [PCR with type-specific primers at the core region (primer-set), slot-blot hybridization with type-specific probes at NS5B region (blotting) and the restric fragment length polymorphism analysis of PCR products of 5' NC region (RFLP)]. Ten samples with the known genotype were analysed by the direct sequencing. RESULTS: Of 30 samples with positive HCV RNA, the types of 22 could be classified by three methods, and the genotypes determined by various methods had complete concordance. The types of 6 samples could be classified by two methods and 5 had agreement subtypes. The types of two samples could be classified only by RFLP. Overall, 27 (90.0%) had subtype 1b infection and 3 (10.0%) had subtype 2a infection. The nucleotide sequence of 8 samples with subtype 1b and one with subtype 2a were analysed by the direct sequencing. The subtypes determined by sequence analysis were in complete concordance with those decided by various genotyping methods. CONCLUSIONS: Subtype 1b is the predominent HCV genotype in Guizhou area, while subtype 2a is less common. There was a good concordance with the genotyping results obtained by various HCV genotyping methods.

Antibodies, Viral↗
PubMed1998

[Examination of eustachian tube function in chronic suppurative otitis media].

Discussing something about the methods of examining the eustachian tube function of chronic suppurative otitis media. The examination of the eustachian tube function were given on 96 cases of chronic suppurative otitis media with Valsalva method, tympanium drip and acoustic impedance method. Though the former two methods were imperfect, the combination of them was similar to the acoustic impedance method in outcome, which is easy and convenient and doesn't need expensive instrument. The combination of the former two methods in result could get rid of the imperfection of each of them and could evaluate the eustachian tube function in accuracy, which is fit for basic-level hospital.

Acoustic Impedance Tests↗
PubMed1998

Single-strand conformation polymorphism for analysis of genomic variability of hepatitis C virus nonstructure 5A region.

OBJECTIVE: To establish a convenient method to detect the genomic population with hepatitis C virus (HCV) at nonstructure 5A (NS5A) region and to determine the correlation between the genomic population complexity at NS5A region and disease stage. METHODS: The sera from 52 patients with chronic hepatitis C virus infections were analysed using single strand conformation polymorphism (SSCP). In the SSCP, an asymmetric polymerase chain reaction (PCR) was carried out on the 455 bp products of the first round PCR at the NS5A region and the number of band of single strand deoxyribonucleic acid (DNA) which reacted with complemental DNA probe specific for the NS5A region after gel electrophoresis was analyzed. RESULTS: In 90% patients with chronic persistent hepatitis, the bands of single strand DNA was limited to one, and in those with chronic active hepatitis or liver cirrhosis, two or more bands of DNA were frequently detected. In about half of patients with hepatocellular-carcinoma, three or more bands were found. The number of bands increased with the progression of liver disease. The multivariate analysis showed that the progression of liver disease was the independent factor of viral diversity (P < 0.025) and was not related to the age, sex, the route of infection and the titer of hepatitis C virus ribonucleic acid (HCV RNA). CONCLUSION: These results suggest that the genomic variability of HCV at NS5A region increases with the progression of liver disease, and this may be closely related to the clinical features of type C liver disease.

Base Sequence↗
PubMed1998

[The relationship between cytosolic Ca2+ and two kinds of granule number in activated platelets].

The numerical density (Nv) of the alpha-granule (alpha G) and dense granule (dG) measured by using electron microscopic morphometry and the cytosolic free calcium concentration ([Ca2+]i) by using Ca-fluorescent indicator were observed for studying the relationship of [Ca2+]i and Nv of alpha G and dG in platelets activated by A23187, thrombin or ADP. The results showed that the [Ca2+]i rose markedly by A23187. Thrombin or ADP could also induce an increase of [Ca2+]i concentration-dependently. Under 3 different degrees of activation induced by different agonists, the close relationship between Nv of both granules, alpha G and dG, and [Ca2+]i in platelets was found (Pr(alpha G) < 0.05, Pr(dG) < 0.01). These findings indicate that the increase in [Ca2+]i may enhance the secretion of alpha G and dG.

Animals↗
PubMed1998

[Dye coupling between visual cortical (area 17) neurones of adult rat--a study on brain slices].

With intracellular injection of biocytin, forty-nine neurones were successfully labeled in in vitro visual cortex (area 17) slices of the adult rat. Out of the sample dye coupling was found in 21 cases, for each injection the number of the coupled cells varying from 2 to 5 (mean 2.8 +/- 1.1). Eighteen couplings were pyramidal-pyramidal, two were pyramidal-nonpyramidal, and one was seen among non-pyramidal cells. In most cases, the coupled cells were apart from each other with a certain distance among their cell bodies (mean 43.1 +/- 24 microns). The longest distance was up to 635 microns. Most couplings (19/21) were observed within the same lamina; only two in different laminae. The dye couplings were found in laminae II/III, IV and V, but mostly in laminae II/III. We have measured membrane potential and response properties to white matter and intracellular stimulation for the coupled and non-coupled cells; no significant difference was found between them.

Animals↗
PubMed1998

[Surgical treatment of tuberculous tracheobronchial stenosis].

OBJECTIVE: To report the experience of surgical treatment of tuberculous tracheobronchial stenosis. METHOD: Two trachial stenosis and 33 bronchial stenosis cases were analyzed. The modes of surgical treatment included: pneumonectomy in 14 cases, lobectomy in 13, lobectomy combined with bronchoplasty in 3, right pneumonectomy and partial trachial resection in 2, right main bronchus sleeve resection in 1, endotrachial granuloma resection in 1, right pneumonectomy and partial trachial resection combined with trachial reconstruction in 1. RESULT: There was no bronchopleural fistula, tracheobronchial restenosis and death due to operation. CONCLUSION: The first choice for the treatment of tuberculous tracheal or bronchial stenosis is lobectomy or pneumonectomy with trachial or bronchial plasty surgery.

Adult↗
PubMed1998

[Effects of dexamethasone on apoptosis of airway inflammatory cells in asthmatic guinea-pigs].

OBJECTIVE: Clearance of airway inflammatory cells is the key point of therapeutic effect in asthma. Apoptosis, a form of cell death, is thought to be critically important to promote the clearance of inflammatory cells and the resolution of inflammation. To investigate the effects of dexamethasone on apoptosis of airway inflammatory cells in asthma showed be very important. METHOD: Dexamethasone was used for the treatment of asthma model of guinea pigs set up by inhaling ovalbumin. Apoptotic cells were labelled with TdT-mediated dUTP nick end labeling(TUNEL) technique on formalin-fixed paraffin-embedded trachea and lung tissue sections. By way of immunohistochemistry, eosinophils were stained with EG2 antibody and T lymphocytes with CD3+, CD4+ and CD8+ antibodies on sections. RESULT: (1) The quantity of airway eosinophils and lymphocytes decreased in dexamethasone group, which could not be observed in the control one (P < 0.01). (2) Apoptotic index of lymphocytes was significantly elevated following dexamethasone treatment(P < 0.05). But no difference was found in the proportion of apoptotic eosinophils between these two groups. (3) The percentage of EG2 positive eosinophils and CD4+ positive lymphocytes decreased significantly following dexamethasone treatment. On the contrary, the number of CD8+ lymphocytes increased in dexamethasone group when compared with the control one (P < 0.05). CONCLUSION: (1) The quantity of airway eosinophils decreases following dexamethasone treatment in guinea-pigs asthma, and its mechanism may not be ascribed mainly to the apoptosis of eosinophils. (2) The number of lymphocytes, mainly CD4+, decreased following dexamethasone treatment in guinea-pig airways, and apoptosis may represent the mechanism that promotes the clearance of lymphocytes in asthma.

Animals↗
PubMed1998

[Diagnosis and treatment of pulmonary sequestration].

OBJECTIVE: To explore the cause, classification, incidence, diagnosis and treatment of pulmonary sequestration. METHOD: 42 cases analysed and literatures reviewed. RESULT: 42 cases of sequestration were presents which were resected and confirmed by pathology in our department from 1964 to 1997. 29 cases (69%) were confirmed before operation. The incidence rate was 0.32% comparing with the sametime operations. There were 37 cases (88%) of intralobar type, and 5 cases (12%) of extralobar type. 22 cases accompanied with infection, 9 cases with hemoptysis in intralobar type. 1 case with infection and 1 case with hemoptysis in extralobar type, in the latter case, there was a fistula between the affected lung and the esophagus. CONCLUSION: Pulmonary sequestration is not a rare illness. The diagnosis mainly depends on X-ray. Sometimes, bronchography, retrograde arteriography or CT can also make the diagnosis correctly. Special attention should be paid to avoiding injure to the vessels which supply the isolated lung during operation.

Adolescent↗
PubMed1998

[Correlations between factors and intraocular pressure following photorefractive keratectomy].

OBJECTIVE: To evaluate the factors related to intraocular pressure (IOP) after excimer laser photorefractive keratectomy (PRK). METHODS: 86 cases 150 eyes of myopia followed over six months after PRK were studied with noncontact tonometer (NCT). RESULT: After PRK, a decrease in the IOP was observed. Post-operatively, the IOP reading at 1st month was the highest. The reduction of IOP may be related to the decrease in corneal thickness and corneal curvature (r = 0.361, P < 0.01; r = 0.188, P < 0.05). Regression equation for IOP drop (kPa) = - 0.059 - 0.038X(1) + 0.009X(2)[X(1) = ablation depth (microm), X(2) = decrease in corneal curvature (D)]. CONCLUSION: IOP readings after PRK are influenced by corneal thickness, corneal curvature and eye drug times.

Adult↗
PubMed1998

[In vitro release kinetics and hypoglycemic effect on diabetic rats after oral administration of insulin loaded nanoparticles].

The insulin-loaded polyalkylcyanoacrylate nanoparticles (INS-NP) were made with Dextran 70 as the stabilizer. The mean diameter of INS-NP was 252.4 nm with a poly dispersity of 0.005. The associating ratio of insulin to the nanoparticles reached 70.1% +/- 2.3%, while the loading capacity was 0.14 u.mg-1. Studies on in vitro release kinetics showed that release profiles can be well modelled using a biexponential function. The burst effect was obvious, and a faster release was observed in acidic media. After various doses of INS-NP were intragastrically given to diabetic rats, significant decrease of glucose level was achieved in the 10 and 20 u.kg-1 groups, with no significant difference between these two doses. The relative bioavailability after p.o. administration of INS-NP 10 u.kg-1 over s.c. administration of insulin solution 1 u.kg-1 was 7.58% calculated by the area over the curve of glucose level (%) versus time profiles. The correlation was obvious between the % of insulin released at pH 7.0 and the % of glucose decreased within the first 7 hours. Hence, an oral insulin preparation with rather high bioavailability was provided in this study, and its shorter effective time will make it more convenient for the control of the glucose level in clinics.

Animals↗
PubMed1998

[Study on the interaction of Et2SnCl2(phen) with DNA].

The absorbance, fluorescence and cyclic voltammetric methods as well as agarose gel electrophoresis were used to study the interaction of the antitumor compound Et2SnCl2(phen) with DNA. The results indicate that Et2SnCl2 (phen) mainly reacts electrostatically with the phosphate backbone of DNA. There also exists an intercalation into the double-helix of DNA through the phenanthroline group of Et2SnCl2(phen). At high concentration Et2SnCl2(phen) can cause unwinding of DNA. The molecular action mechanism of Et2SnCl2(phen) with DNA was first proposed.

Animals↗
PubMed1998

Factors associated with atypical nevi: a population-based study.

We conducted a case-control study to identify factors associated with the presence of clinically atypical nevi. Potential participants were selected, using a two-staged sampling scheme, from a population-based cohort of 50,000 Swedish women who had responded to a previous health survey questionnaire. Of 500 women sampled for study recruitment, 400 (80%) agreed to participate. Study participants underwent a physician-conducted skin examination, which identified 130 women who had at least one clinically atypical nevus (cases) and 270 women without these lesions (controls). The physician-conducted skin examination also assessed women for benign nevus counts; other risk factor information was based upon responses to a health survey questionnaire. We found a strong and highly statistically significant relationship between number of benign nevi and the presence of at least one clinically atypical nevus (P < 0.0001). Women with 100 or more benign nevi had a 26-fold increased likelihood of having an atypical nevus. We noted statistically significant interactions between number of benign nevi and other factors of interest; thus, the results are reported separately for women with low (<50) or high (> or =50) counts of benign nevi. Among women with low counts of benign nevi, the likelihood of having an atypical nevus increased with degree of freckling; there was also a suggested role for early sun exposure. Among women with high counts of benign nevi, difficulty tanning and lack of peeling sunburns between ages 10 and 19 appeared to increase the likelihood of case status; our data also suggested an inverse relationship between parity and atypical nevi in this subgroup.

Adult↗
PubMed1998

How do HMOs achieve savings? The effectiveness of one organization's strategies.

OBJECTIVE: To examine how a group practice used organizational strategies rather than provider-level incentives to achieve savings for health maintenance organization (HMO) compared to fee-for-service (FFS) patients. DATA SOURCES/STUDY SETTING: A large group practice with a group model HMO also treating FFS patients. Data sources were all patient encounter records, demographic files, and clinic records covering 3.5 years (1986-1989). The clinic's procedures to record services and charges were identical for FFS and HMO patients. All FFS and HMO patients under age 65 who received any outpatient services during approximately 100,000 episodes of the seven study illnesses were eligible. STUDY DESIGN: Using an explanatory case design, we first compared HMO and FFS rates of resource utilization, in standardized dollars, which measured the impact of organizational strategies to influence patient and provider behavior. We then examined the effect of HMO insurance and organizational measures to explain total outpatient use. Key variables were standardized charges for all outpatient services and the HMO's strategies. PRINCIPAL FINDINGS: Patient and provider behavior responded to organizational strategies designed to achieve savings for HMO patients; for instance, HMO patients used midlevel providers and generalists more often and ER and specialists less often. Overall HMO savings, adjusted for case mix, were explained by the specialty of the physicians the patients first visited and appeared to affect patients with average health more than others. CONCLUSION: Organizational strategies, without resort to differential financial incentives to each provider, resulted in lower rates of outpatient services for HMO patients. Savings from outpatient use, especially for common diseases that rarely require hospitalization, can be substantial.

Adult↗
PubMed1997

Application of mixed mobile phases and a step gradient method in capillary electrochromatography for the separation of isomeric polycyclic aromatic hydrocarbon-deoxyribonucleoside adduct mixtures prepared in vitro.

Capillary electrochromatography (CEC) was used for the analysis of mixtures of neutral isomeric compounds derived from the reaction of carcinogenic hydrocarbon (benzo[g]chrysene and 5,6-dimethylchrysene) dihydrodiol epoxides with calf thymus deoxyribonucleic acid (DNA). The CEC analysis demonstrated higher resolution, greater speed and lower analyte consumption than high-performance liquid chromatography (HPLC) in the analysis of the same samples using the same type of stationary phase. Proper selection of the mixed mobile phases was critical for the separation of these complex mixtures with enhanced speed and selectivity. The use of a step gradient further improved the speed of the CEC analysis resulting in electrochromatograms that required only 25-70% of the corresponding HPLC analysis times.

DNA Adducts↗
PubMed1997

Capillary electrochromatography and capillary electrochromatography-mass spectrometry for the analysis of DNA adduct mixtures.

Capillary electrochromatography (CEC) is an emerging technique that can be applied to the separation of neutral compound mixtures and provides a versatile alternative to micellar electrokinetic chromatography. In this paper, CEC is applied to the separation of polycyclic aromatic hydrocarbons (PAHs) and in vitro reaction products of PAH deoxynucleoside adducts. Some unique features related to CEC, such as convenience of stopping the flow, nanoliter flow rate, and low sample consumption, are discussed. On-column focusing in CEC can be conducted by introducing the analytes in a solution of lower solvent strength followed by elution with a stronger mobile phase, in a manner analogous to that used in normal HPLC (e.g., a 10-fold preconcentration factor can be readily achieved). Coupling of CEC to mass spectrometry for the detection of a relatively dilute DNA adduct mixture solution (10(-6) M) using the on-column focusing method is also presented.

DNA Adducts↗
PubMed1997

Protein-nucleic acid interactions and DNA conformation in a complex of human immunodeficiency virus type 1 reverse transcriptase with a double-stranded DNA template-primer.

The conformation of the DNA and the interactions of the nucleic acid with the protein in a complex of human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) and 19-mer/18-mer double-stranded DNA template-primer (dsDNA) are described. The structure of this HIV-1 RT complex with dsDNA serves as a useful paradigm for studying aspects of nucleotide polymerases such as catalysis, fidelity, drug inhibition, and drug resistance. The bound dsDNA has a bend of approximately 41 degrees at the junction of an A-form region (first five base pairs near the polymerase active site) and a B-form region (the last nine base pairs toward the RNase H active site). The 41 degrees bend occurs smoothly over the four base pairs between the A-form portion and the B-form portion in the vicinity of helices alpha H and alpha I of the p66 thumb subdomain. The interactions between the dsDNA and protein primarily involve the sugar-phosphate backbone of the nucleic acid and structural elements of the palm, thumb, and RNase H of p66, and are not sequence specific. Amino acid residues from the polymerase active site region, including amino acid residues of the conserved Tyr-Met-Asp-Asp (YMDD) motif and the "primer grip," interact with 3'-terminal nucleotides of the primer strand and are involved in positioning the primer terminal nucleotide and its 3'-OH group at the polymerase active site. Amino acid residues of the "template grip" have close contacts with the template strand and aid in positioning the template strand near the polymerase active site. Helix alpha H of the p66 thumb is partly inserted into the minor groove of the dsDNA and helix alpha I is directly adjacent to the backbone of the template strand. Amino acid residues of beta 1', alpha A', alpha B', and the loop containing His539 of the RNase H domain interact with the primer strand of the dsDNA.

DNA↗
PubMed1997

Cofilin undergoes rapid dephosphorylation in stimulated neutrophils and translocates to ruffled membranes enriched in products of the NADPH oxidase complex. Evidence for a novel cycle of phosphorylation and dephosphorylation.

Neutrophils contain a 21-kDa phosphoprotein that undergoes rapid dephosphorylation upon stimulation of these cells with the chemoattractant N-fMet-Leu-Phe (fMLP), activators of protein kinase C [e.g., 4 beta-phorbol 12-myristate 13-acetate (PMA)] or the calcium ionophore A23187. This phosphoprotein was identified as the non-muscle form of cofilin by peptide sequencing and immunoblotting with specific antibodies. Evidence is presented that in neutrophils cofilin is regulated by a continual cycle of phosphorylation and dephosphorylation, and that the phosphatase undergoes activation during cell stimulation. Experiments with a wide variety of antagonists further suggested that the protein kinase that participates in these reactions may be a novel enzyme. The kinetics of cofilin dephosphorylation in neutrophils stimulated with fMLP or PMA were very similar to those observed for superoxide (O2-) release. Immunofluorescent studies revealed that cofilin was present throughout the cytosol of resting neutrophils and underwent rapid translocation to the F-actin-rich, ruffled membranes of stimulated cells. Cytochemical analysis further revealed that the ruffled membranes also contained large amounts of hydrogen peroxide (H2O2), a product of the O2-/H2O2-generating activity of stimulated neutrophils (NADPH oxidase). Cofilin is therefore well placed to participate in the continual polymerization and depolymerization of F-actin that is thought to give rise to the oscillatory pattern of H2O2 production observed under certain conditions.

Actin Depolymerizing Factors↗