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Biomedical subjects

B Dong

Publications and source records attributed to B Dong.

At least 37 records · Page 2Linked to original sources
PubMed2001

[Smoking and alcohol consumption as risk factors of pulmonary tuberculosis in Chengdu: a matched case-control study].

OBJECTIVE: The aim of this study was to assess the relationship between personal behaviors (smoking and alcohol consumption) and contracting pulmonary tuberculosis. METHODS: 346 persons (173 cases and 173 controls) were selected from 12 communities of Chengdu area, all the cases were active TB patients (by WHO criteria) from March 1996 to March 1997. Controls were matched for age, sex and living district. Subjects were interviewed face to face by trained interviewers using questionnaires. RESULTS: The results of univariate analysis showed that active smoking (OR = 2.12, P = 0.006), passive smoking (OR = 1.55, P = 0.04), type of cigarettes (OR = 1.31, P = 0.005) and alcohol consumption (OR = 1.81, P = 0.008) were significantly associated with TB. Yet, multivariate logistic regression analysis did not find smoking or alcohol consumption being in independent association with TB, but it showed that persons who were smokers with the addition of alcohol consumption had a higher risk to contract TB (OR = 7.729, 95% C.I. = 1.5215-39.2634). Significant association was noted in the dose-response analysis (OR = 1.73, 95% C.I. = 1.300-2.3028). CONCLUSION: These data indicate that smoking alone or sole alcohol consumption bears no relationship with TB, but smoking plus alcohol abuse is probably a risk factor for pulmonary tuberculosis in Chengdu, and in this connection, a proposal of prospective study to further demonstrate this risk factor is warranted.

Adolescent↗
PubMed2000

[Effect of percutaneous microwave coagulation therapy on local immune response in patients with hepatocellular carcinoma].

OBJECTIVE: To assess the local immune response to percutaneous microwave coagulation therapy (PMCT) for hepatocellular carcinoma (HCC). METHODS: Seventy-eight patients with HCC underwent PMCT. Samples of cancer and adjacent liver tissues were taken at pre-therapy, and 3, 17 and 30 days after therapy by ultrasound-guided biopsy and were stained by immunohistochemical technique. The CD3, CD45RO, CD56, CD68 and CD20 positive cells were detected in the tissue section and counted under a microscope. RESULTS: There were some CD3, CD45RO, CD56, CD68 and CD20 positive cells scattered among the cancer stroma and sinusoids and surrounding liver tissue pre-therapy. Those cells increased significantly at the third day post-therapy compared with those of pre-therapy both in cancer and adjacent liver tissues, except CD20 positive cells. The number of infiltrating immunocytes was related to the basic immune state of patients (r = 0.56, P = 0.013). Those immunocytes scattered among the parenchymal area of the tumor, the lumen of small blood vessels and the stroma closing to small vessels. The number of CD45RO and CD56 cells reached their highest point at the day 17 and CD68 positive cells at day 3 and sustained to the day 30 after PMCT. Those immunocytes were seen among the cancer cells and the lumen of small blood vessels after. CONCLUSION: The number of immunocytes in the lesion area is increased and the local immune function is enhanced by PMCT.

Adult↗
PubMed2000

[Study of graft-versus -leukemia activity of gamma-ray irradiated haplomismatched donor lymphocytes infusion].

OBJECTIVE: To explore graft-versus-leukemia activity of 7.5 Gy gamma-ray irradiated haplomismatched donor lymphocytes infusion (DLI). METHODS: L615 cells loaded 615 (H2(k))/BALB/c (H-2(d)) F(1) mice were infused with irradiated haplo-mismatched donor lymphocytes at 3, 5, 7 days after CTX (200 mg/kg) treatment which was given at the 3rd day after L615 cells inoculation. RESULTS: T-cells irradiated with 7.5 Gy gamma-ray lost their proliferative capacity but preserved their cytotoxic activity against allogeneic targets. Survival of these recipient mice was longer than that of control (t = 10.03, P < 0.001) with no severe graft-versus-host disease (GVHD). CONCLUSION: 7.5 Gy gamma irradiation attenuated the GVHD inducing potential of allogeneic lymphocytes while preserving their graft-versus-leukemia activity. It provides a simple modality to postpone and prevent leukemia relapse.

Animals↗
PubMed1999

Alternative function of a protein kinase homology domain in 2', 5'-oligoadenylate dependent RNase L.

RNase L is the 2',5'-oligoadenylate (2-5A)-dependent endoribonuclease that functions in interferon action and apoptosis. One of the intriguing, albeit unexplained, features of RNase L is its significant homology to protein kinases. Despite the homology, however, no protein kinase activity was detected during activation and RNA cleavage reactions with human RNase L. Similarly, the kinase plus ribonuclease domains of RNase L produced no detectable protein kinase activity in contrast to the phosphorylation obtained with homologous domains of the related kinase and endoribonuclease, yeast IRE1p. In addition, neither ATP nor pA(2'p5'A)3was hydrolyzed by RNase L. To further investigate the function of the kinase homology in RNase L, the conserved lysine at residue 392 in protein kinase-like domain II was replaced with an arginine residue. The resulting mutant, RNase LK392R, showed >100-fold decreases in 2-5A-dependent ribonuclease activity without reducing 2-5A- or RNA-binding activities. The greatly reduced activity of RNase LK392Rwas correlated to a defect in the ability of RNase L to dimerize. These results demonstrate a critical role for lysine 392 in the activation and dimerization of RNase L, thus suggesting that these two activities are intimately linked.

Adenine Nucleotides↗
PubMed1999

[Evaluation of preventive studies of Chinese Journal of Tuberculosis and Respiratory Diseases 1978-1997].

OBJECTIVE: To investigate the current situation of clinical trial about preventive research paper on respiratory diseases in China. To stress the design of the research, and to improve the quality of the studies. METHODS: All the preventive and treatment studies of Chinese Journal of Tuberculosis and Respiratory Diseases (1978-1997) were assessed according to evidence based medicine (EBM) standard. RESULTS: In the past 20 years, 394 preventive study papers were published, 41 were random control trial (RCT), 50 were clinical control trial (CCT), the total percentage of RCT and CCT was 23.1%, and quality problem also existed. CONCLUSIONS: The design of the study in the respiratory diseases is not rigorous, thus the accuracy of the result is greatly affected. Improving the design of the research and the statistics method is very important to improve the quality of the research.

China↗
PubMed1998

Right ventricular outflow tract tachycardia due to a somatic cell mutation in G protein subunitalphai2.

Idiopathic ventricular tachycardia is a generic term that describes the various forms of ventricular arrhythmias that occur in patients without structural heart disease and in the absence of the long QT syndrome. Many of these tachycardias are focal in origin, localize to the right ventricular outflow tract (RVOT), terminate in response to beta blockers, verapamil, vagal maneuvers, and adenosine, and are thought to result from cAMP-mediated triggered activity. DNA was prepared from biopsy samples obtained from myocardial tissue from a patient with adenosine-insensitive idiopathic ventricular tachycardia arising from the RVOT. Genomic sequences of the inhibitory G protein Galphai2 were determined after amplification by PCR and subcloning. A point mutation (F200L) in the GTP binding domain of the inhibitory G protein Galphai2 was identified in a biopsy sample from the arrhythmogenic focus. This mutation was shown to increase intracellular cAMP concentration and inhibit suppression of cAMP by adenosine. No mutations were detected in Galphai2 sequences from myocardial tissue sampled from regions remote from the origin of tachycardia, or from peripheral lymphocytes. These findings suggest that somatic cell mutations in the cAMP-dependent signal transduction pathway occurring during myocardial development may be responsible for some forms of idiopathic ventricular tachycardia.

Amino Acid Sequence↗
PubMed1998

Uptake and translocation of phosphate by pho2 mutant and wild-type seedlings of Arabidopsis thaliana.

The pho2 mutant of Arabidopsis thaliana (L.) Heynh. accumulates excessive Pi (inorganic phosphate) concentrations in shoots compared to wild-type plants (E. Delhaize and P. Randall, 1995, Plant Physiol. 107: 207-213). In this study, a series of experiments was conducted to compare the uptake and translocation of Pi by pho2 with that of wild-type plants. The pho2 mutants had about a twofold greater Pi uptake rate than wild-type plants under P-sufficient conditions and a greater proportion of the Pi taken up accumulated in shoots of pho2. When shoots were removed, the uptake rate by roots was found to be similar for both genotypes, suggesting that the greater Pi uptake by the intact pho2 mutant is due to a greater shoot sink for Pi. Although pho2 mutants could recycle 32Pi from shoots to roots through phloem the proportion of 32Pi translocated to roots was less than half of that found in wild-type plants. When transferred from P-sufficient to P-deficient solutions, Pi concentrations in pho2 roots had a similar depletion rate to wild-type roots despite pho2 shoots having a fourfold greater Pi concentration than wild-type shoots throughout the experiment. We suggest that the pho2 phenotype could result from a partial defect in Pi transport in the phloem between shoots and roots or from an inability of shoot cells to regulate internal Pi concentrations.

Arabidopsis↗
PubMed1998

[Electronic speckle pattern interferometric analysis on force distribution of different mandibular unilateral free-end dentures].

OBJECTIVE: To study the force distribution of three kinds of mandibular unilateral free-end partial denture under vertical loading on the artificial tooth. METHODS: A fresh mandible with right 2nd and 3rd molars missing was restored with cantilever fixed partial denture (CFD), casting three arm clasp removable partial denture (CCD) and RPI removable partial denture (RPID) respectively. The force distribution on the surface of supporting bone was studied by using electronic speckle pattern interferometry (ESPI). The ESIP was displayed real-time and recorded. The fringes determining was prossed by microcomputer image processing. The corresponding out of plane displacement of the supporting bone was measured and analyzed. RESULTS: Showed all of the three kinds of dentures contribute to transmit stress to supporting bone. The corresponding out of plane displacement of supporting bone decreased, the degree of decrease was CFD < CCD < RPID in order. CONCLUSION: This finding provides a useful reference for design of denture construction.

Adult↗
PubMed1997

Interferon action and apoptosis are defective in mice devoid of 2',5'-oligoadenylate-dependent RNase L.

2',5'-Oligoadenylate-dependent RNase L functions in the interferon-inducible, RNA decay pathway known as the 2-5A system. To determine the physiological roles of the 2-5A system, mice were generated with a targeted disruption of the RNase L gene. The antiviral effect of interferon alpha was impaired in RNase L-/- mice providing the first evidence that the 2-5A system functions as an antiviral pathway in animals. In addition, remarkably enlarged thymuses in the RNase L-/- mice resulted from a suppression of apoptosis. There was a 2-fold decrease in apoptosis in vivo in the thymuses and spleens of RNase L-/- mice. Furthermore, apoptosis was substantially suppressed in RNase L-/- thymocytes and fibroblasts treated with different apoptotic agents. These results suggest that both interferon action and apoptosis can be controlled at the level of RNA stability by RNase L. Another implication is that the 2-5A system is likely to contribute to the antiviral activity of interferon by inducing apoptosis of infected cells.

Adenine Nucleotides↗
PubMed1997

A bipartite model of 2-5A-dependent RNase L.

The 2-5A-dependent RNase (RNase L) is a tightly regulated endoribonuclease of higher vertebrates that is catalytically active only after engaging unusual effector molecules consisting of the 2',5'-linked oligoadenylates, p1-3A(2'p5'A)>/=2 (2-5A). Progressive truncations from either terminus have provided insight into the structure, function, and regulation of RNase L. We determined that deletion of the N-terminal 335 amino acids of RNase L, about 45% of the enzyme, produced a constitutively active endoribonuclease, thus effectively eliminating the requirement for 2-5A. The truncated nuclease had 6-fold lower catalytic activity against an oligo(rU) substrate than wild type RNase L. However, the two enzymes showed identical RNA cleavage site preferences with an mRNA as substrate. The repressor function required only the last three of a series of nine ankyrin-like repeats present in the N-terminal part of RNase L. In contrast, the entire ankyrin repeat region was necessary and sufficient for 2-5A binding activity. Deletion of a 10-amino acid sequence near the C terminus of RNase L, between residues 710 and 720, eliminated both the catalytic and RNA substrate binding functions of the enzyme. The ability to bind native RNase L in response to 2-5A required amino acid sequences near both termini of the protein. A bipartite model for the structure of RNase L emerged in which the regulatory functions of the molecule are located in the N-terminal half, while the catalytic domain is present in the C-terminal half.

Binding Sites↗
PubMed1997

The cloning of two Arabidopsis genes belonging to a phosphate transporter family.

Two genes, APT1 and APT2, with DNA sequences that exhibit significant sequence identity to yeast and fungal H+/orthophosphate co-transporters, have been isolated from Arabidopsis thaliana. These genes are genetically linked and map to chromosome 5 between markers g4028 and m435. The genes encode almost identical 524 amino acid polypeptides and are predicted to contain 12 membrane-spanning domains. Both APT1 and APT2 are predominantly expressed in A. thaliana root tissues. The level of expression of both genes in roots is regulated by the phosphorus status of the plant, being considerably enhanced when the plants were deprived of an external phosphate supply. The APT1 and APT2 polypeptides are likely to be associated with the membrane transport of phosphate within A. thaliana roots.

Amino Acid Sequence↗
PubMed1997

The intracisternal A-particle proximal enhancer-binding protein activates transcription and is identical to the RNA- and DNA-binding protein p54nrb/NonO.

The long terminal repeats of murine intracisternal A particles (IAPs) contain an IAP proximal enhancer (IPE) element that is inactive in murine F9 embryonal carcinoma cells and active in the parietal endoderm cell line PYS-2. The element binds efficiently to a 60-kDa IPE-binding protein (IPEB) present in PYS-2 cells but poorly to F9 proteins, suggesting a role for IPEB in regulating IAP expression. We have purified calf thymus IPEB, which binds to the IPE and transactivates a reporter gene in HeLa cell extracts. Based on the peptide sequence of the purified calf IPEB, we have cloned a 420-bp cDNA and showed that the encoded protein is the homolog of human p54nrb and mouse NonO, which are characterized by the presence of two RNA recognition motifs. We show that p54nrb is an IPE-binding transcription activator with its DNA-binding and activation domains in the N- and C-terminal halves, respectively. The activation domain of p54nrb is active in HeLa, PYS-2, and F9 cells, whereas p54nrb as a whole molecule is active in HeLa and PYS-2 cells but not in F9 cells. Thus, the lack of activity of p54nrb in F9 cells is due to an ineffective DNA-binding domain. We demonstrate that p54nrb also binds to a pre-mRNA. Based on the close sequence relatedness of this protein to PSF, which is required for pre-mRNA splicing in vitro, we discuss the possibility that p54nrb has dual roles in transcription and splicing.

Animals↗
PubMed1997

[Clinical application of ultrasound(US)-guided percutaneous microwave coagulation therapy for liver cancer].

OBJECTIVE: To evaluate clinical application of US-guided percutaneous microwave coagulation therapy for liver cancer. METHODS: 32 patients with 57 nodules of liver cancer were treated, 57 nodules were coagulated by 92 times at 182 different points. Output of one coagulation was 60 W last mg 240-300 sec. RESULTS: The follow-up period was 5-18 months, averaging 10.4 months. 29 patients remained alive, 3 patients died. After treatment, 85.9%(49/57) of the nodules decreased in size; color blood flow signal disappeared in 78.2(36/46) nodules on color and energy Doppler scans; and there was no enhancement in 76.4%(25/34) tumors on enhanced CT scans. In 13 patients with increased AFP level before therapy, it dropped to normal after treatment in 11 patients. Of 27 patients whoes a good general condition was good, 19 patients gained bodies weight. Repeated biopsy in 14 cases showed complete tumor necrosis with fibrosis in 12. CONCLUSION: US-guided percutaneous microwave coagulation therapy is able to induce total tumor necrosis of liver cancer in most cases. It can be expected as an important non-operative therapy of liver cancer.

Adult↗
PubMed1997

[Preparation and evaluation of stationary phase of high performance liquid chromatography for the separation of basic solutes].

A bonded phase for high performance liquid chromatography (HPLC) has been prepared by the new reaction between silica and silicon ether. The ether was synthesized from alkylchlorosilane and pentane-2,4-dione in the presence of imidazole under inert conditions by using anhydrous tetrahydrofuran as solvent. The bonded phase thus obtained was characterized by elemental analysis, diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy and HPLC evaluation. The carbon content was 9.4% and the surface coverage almost attained 3.0micromol/m2 without end-capping. The silanol absorption peaks of the product cannot be observed from the DRIFT spectrum, which revealed that the silanization reaction proceeded thoroughly. The basic solutes, such as aniline, o-toluidine, p-toluidine, N,N-dimethylaniline and pyridine were used as the probe solutes to examine their interaction with the residual silanols on the surface of the products. No buffer or salt was used in the mobile phase for these experiments. In comparison with an acidic solute, such as, phenol, basic aniline eluted in front of phenol, and the ratio of asymmetry of aniline peak to that of the phenol peak was 1.1. Furthermore the relative k' value of p-toluidine to that of o-toluidine was also 1.1. All the results showed that the stationary phase has better quality and reproducibility and can be used for the separation of basic solutes efficiently.

English Abstract↗
PubMed1997

[Dynamic study on blood lead levels of pregnant women and infants in a district of Beijing].

Under strict quality control, the authors investigated the levels of PbB among 270 women from early pregnancy to delivery and their infants. The mean PbB levels of the first three months of pregnancy and delivery is 45.0 microg/L and 64.8 microg/L respectively. Analysis shows an increase of mean PbB level in the period of gestation, and a significant increase in the last three months. The mean PbB level of umbilical cord is 51.9 microg/L (10.4% umbilical cord PbB > 100 microg/L). The mean PbB level of infants increases with the months, it increases significantly after six months. Regression analysis confirmed the positive correlation between the PbB levels of first three and second three months of gestation, the PbB of delivery and umbilical cord, the PbB of umbilical coral and infants. The correlation coefficient of the PbB level of delivery and umbilical cord, the PbB level of infants at six months and at twelve months is 0.80 and 0.47 respectively.

China↗