Biomedical subjects

J Dong

Publications and source records attributed to J Dong.

At least 55 records · Page 3Linked to original sources

PubMed2001

Experimental study on AT1-receptor-peptide-induced myocardial immune damage in rat.

In order to investigate the immunological damage in rat immunized with AT1-receptor peptide, 18 male Wistar rats were divided into two groups: immunized-group (n = 12), each rat was immunized with 150 micrograms AT1-receptor peptide coupled to bovine serum albumin, together with Freund's adjuvant. Control group (n = 6), sham-immunized, "immunized liquid" was same as immunized-group except AT1-receptor peptide. Systolic blood pressure (SBP) was measured by using the tail-cuff technique, antibody against AT1-receptor peptide detected by using ELISA method, and left ventricular myocardium and renal cortex sections were observed under light and electron microscopy. There was no significant difference in SBP and light microscopic observation of the tissue sections between the immunized-group and control group. The O.D. value of anti-AT1-receptor peptide antiserum was significantly higher in the immunized-group than in the rats before immunization and control group (P < 0.01). Positive rate in the immunized-group was 100%, while 0% in the control group. Ultramicroscopic morphology showed potential myocardial injury, including: increase in number of mitochondria, swelling of many mitochondria with reduction in number or absence of their cristae and cristolysis, disorder of the cardiac myofibrils, and myofibrillar disruption and myocytolysis. And lysosomes were increased in renal tubular epithelia. The AT1-receptor peptide could induce to generate the antibody against AT1-receptor peptide and lead to myocardial and renal damage in rats.

Animals↗

PubMed2001

Modification of norepinephrine and serotonin, but not dopamine, neuron firing by sustained bupropion treatment.

RATIONALE: Bupropion is widely used in the treatment of depression and as an anti-craving medication for the cessation of tobacco smoking. Because it is a very weak inhibitor of norepinephrine (NE) and dopamine (DA) reuptake, its mechanisms of action remain to be elucidated. METHODS: Bupropion was administered subcutaneously via osmotic minipumps over 2 days to determine its effects on the spontaneous firing activity of NE, serotonin (5-HT), and DA neurons in the brain of anaesthetised male Sprague-Dawley rats. This treatment was used in order to obtain levels of the parent compound and its putatively active metabolites that would more adequately reflect the clinical condition than utilizing acute injections. RESULTS: When given by minipump for 2 days, bupropion produced a dose-dependent attenuation of the mean spontaneous firing NE neurons (7.5 mg/kg per day: 15%; 15 mg/kg per day: 61%; 30 mg/kg per day: 80%) which was reversed by the alpha 2-adrenoceptor antagonist idazoxan. At the highest regimen, the mean firing rate of 5-HT neurons was 100% higher than in control rats, but unaffected in NE-lesioned rats. In contrast, DA neurons in the ventral tegmental area displayed a normal firing rate during the latter bupropion treatment. CONCLUSIONS: Sustained bupropion administration decreased the firing rate of NE neurons due to an increased activation of their inhibitory somatodendritic alpha 2-adrenoceptors. This effect of the bupropion treatment would be attributable mainly to an enhancement of NE release and not to reuptake inhibition. This contention is based essentially on the observation that NE reuptake blockers leave unaltered the firing rate of 5-HT neurons, whereas bupropion enhanced it via a NE-dependent mechanism. The present study did not put into evidence any DA activity of bupropion at the level of the cell body of mesolimbic/cortical DA neurons at a regimen exerting profound alterations of the firing activity of NE and 5-HT neurons.

Action Potentials↗

PubMed2001

Kiddo, a new transposable element family closely associated with rice genes.

The promoter region of the rice ubiquitin2 (rubq2) gene was found to be polymorphic between japonica (T309) and indica (IR24) lines as the result of a 270-bp deletion in T309. A TTATA footprint in the T309 rubq2 promoter suggested that an excision event had occurred, and inspection of the 270-bp region present in IR24 revealed that it had all the characteristics of a miniature inverted repeat transposable element (MITE). Database searches showed that this element is a member of a new MITE family, which we have named Kiddo. Thirty-five complete Kiddo sequences were identified in existing rice genomic sequence databases. They could be arranged into four groups, within-group sequence identity was over 90%, with 65-75% identity between groups. The high sequence similarity within a group indicates that some Kiddo members were recently mobile and may still be active. An additional 24 decayed Kiddo sequences were detected. Interestingly, approximately 80% of 18 Kiddo members from annotated accessions lie within 530 bp of a coding sequence. That approximately 40% of Kiddo members present in genic regions reside in introns suggests that Kiddo transposition entails the use of both DNA and RNA intermediates, and may provide some insight into the origins of individual groups. DNA blot analysis showed that Kiddo is a rice-specific element, although one sequence with limited (72%) similarity to Kiddo group A was detected as a wheat EST. Kiddo family members may represent new molecular and phylogenetic markers, as well as representing valuable materials for studying the molecular mechanisms of MITE transposition.

Arabidopsis Proteins↗

PubMed2001

Distinct regulatory properties of pyruvate dehydrogenase kinase and phosphatase isoforms.

The mammalian pyruvate dehydrogenase complex (PDC) plays central and strategic roles in the control of the use of glucose-linked substrates as sources of oxidative energy or as precursors in the biosynthesis of fatty acids. The activity of this mitochondrial complex is regulated by the continuous operation of competing pyruvate dehydrogenase kinase (PDK) and pyruvate dehydrogenase phosphatase (PDP) reactions. The resulting interconversion cycle determines the fraction of active (nonphosphorylated) pyruvate dehydrogenase (E1) component. Tissue-specific and metabolic state-specific control is achieved by the selective expression and distinct regulatory properties of at least four PDK isozymes and two PDP isozymes. The PDK isoforms are members of a family of serine kinases that are not structurally related to cytoplasmic Ser/Thr/Tyr kinases. The catalytic subunits of the PDP isoforms are Mg2+-dependent members of the phosphatase 2C family that has binuclear metal-binding sites within the active site. The dihydrolipoyl acetyltransferase (E2) and the dihydrolipoyl dehydrogenase-binding protein (E3BP) are multidomain proteins that form the oligomeric core of the complex. One or more of their three lipoyl domains (two in E2) selectively bind each PDK and PDP1. These adaptive interactions predominantly influence the catalytic efficiencies and effector control of these regulatory enzymes. When fatty acids are the preferred source of acetyl-CoA and NADH, feedback inactivation of PDC is accomplished by the activity of certain kinase isoforms being stimulated upon preferentially binding a lipoyl domain containing a reductively acetylated lipoyl group. PDC activity is increased in Ca2+-sensitive tissues by elevating PDP1 activity via the Ca2+-dependent binding of PDP1 to a lipoyl domain of E2. During starvation, the irrecoverable loss of glucose carbons is restricted by minimizing PDC activity due to high kinase activity that results from the overexpression of specific kinase isoforms. Overexpression of the same PDK isoforms deleteriously hinders glucose consumption in unregulated diabetes.

Amino Acid Sequence↗

PubMed2001

Fine-scale mapping using Hardy-Weinberg disequilibrium.

Hardy-Weinberg disequilibrium (HWD) among affected individuals has recently been proposed for fine-scale mapping of disease susceptibility genes. We investigate the statistical properties of several available HWD measures and develop a new HWD measure J for fine-scale mapping. It is shown both theoretically and through simulations that the available HWD measures depend not only on the genetic distance between the marker locus of interest and the disease susceptibility locus, but also on the allele frequencies at the marker locus. On the contrary, the new measure is not affected by the allele frequencies at the marker locus under the following assumptions: (a) there is initial complete linkage disequilibrium between the marker and the disease loci, (b) there are no new mutations at the marker and the disease loci, and (c) the population under study is large. We develop a novel method to estimate the location of the disease susceptibility gene based on the HWD measure J. The estimator is robust to low mutation rates at the marker and the disease loci. We compare the standard error of the estimated disease gene loci using P excess for case-control studies with the standard error using J for case-only studies under various disease models. The newly developed method is successfully applied to a data set on hereditary haemochromatosis (HH).

Analysis of Variance↗

PubMed2001

Creation of a new transgene cloning site near the right ITR of Ad5 results in reduced enhancer interference with tissue-specific and regulatable promoters.

Tissue-specific transgene expression is a valuable research tool and is of great importance in delivering toxic gene products with adenovirus vectors to tumors. Limiting cytotoxic gene expression to the target cells is highly desirable. While a number of successful applications of tissue- and tumor-specific gene expression using Ad vectors has been reported, cloning of some promoters into Ad vectors resulted in modulation or loss of tissue specificity. This phenomenon is likely the result of the interaction of E1A enhancer (and possibly other Ad sequences) with the promoter cloned in the E1 region. We have compared performance parameters of prostate-specific and tet-regulatable promoters in plasmids containing the terminal repeat sequences of Ad5 with or without the E1A enhancer. Subsequently, adenoviral vectors were constructed containing identical expression units either in the E1 region or near the right ITR, and tested in several cell lines. Here, we report that promoters placed near the right ITR of Ad5 retain higher selectivity and lower background expression in both plasmid and adenovirus vectors. We confirm that the E1A enhancer can interfere with the desired activity of nearby promoters, and describe an alternative transgene insertion site for construction of Ad vectors.

Adenoviridae↗

PubMed2001

An algorithm using projection onto subspace of prior distributions for long-wavelength sound wave CT.

The stationary long-wavelength sound wave computed tomography is a nonlinear inverse problem that requires the use of prior information of the object. However, the prior assumptions that are usually used in similar inverse problems are more or less inappropriate. In this paper, a new reconstruction algorithm using the prior information is proposed and compared with subspace regularization method and Marquardt reconstruction algorithms. The simulation shows that the proposed algorithm can give a better reconstructed result whether the actual distribution is compatible or incompatible with the prior distributions.

Algorithms↗

PubMed2001

Slope analysis of the optic disc in eyes with ocular hypertension and early normal tension glaucoma by confocal scanning laser ophthalmoscope.

AIMS: To determine whether quantitative differences in sector based slope can differentiate between eyes with ocular hypertension with and without glaucomatous disc changes and eyes with normal tension glaucoma with glaucomatous disc changes. METHODS: Seventy six eyes with ocular hypertension or early glaucomatous disc changes were consecutively categorised into three groups: 22 eyes with ocular hypertension and no glaucomatous disc changes (OHND); 35 with ocular hypertension and glaucomatous disc changes (OHD); and 19 with normal ocular tension and glaucomatous disc changes (NTD). Twenty eyes served as controls. The average total slope angle and sector based slope angle of the cup, total contour area, effective area, neuroretinal rim area, half depth area, cup to disc ratio, contour variation, mean contour depth, average depth, volume below, half depth volume, and contour tilt were evaluated with a confocal scanning laser ophthalmoscope. RESULTS: The earliest changes in eyes with OHND or OHD started in the slope at the nasal inferior sector (p<0.05), followed by the superior and temporal superior sectors (p<0.05). The mean slopes in eyes with NTD and OHD were steeper than in controls (p<0.05). Statistically significant differences were found between controls and disease groups in the half depth area, mean contour depth, and half depth volume. The cup to disc ratios in eyes with OHD and NTD were greater than in eyes with OHND; the volume below was greater in eyes with NTD than in eyes with OHND and OHD. CONCLUSIONS: The steep slope in the nasal inferior section is the first indicator of glaucomatous nerve defects in many eyes. The half depth parameters, half depth area, and half depth volume may be useful for distinguishing ocular hypertension with and without glaucomatous disc changes.

Adult↗

PubMed2001

Glucose toxicity and the development of diabetes in mice with muscle-specific inactivation of GLUT4.

Using cre/loxP gene targeting, transgenic mice with muscle-specific inactivation of the GLUT4 gene (muscle GLUT4 KO) were generated and shown to develop a diabetes phenotype. To determine the mechanism, we examined insulin-stimulated glucose uptake and metabolism during hyperinsulinemic-euglycemic clamp in control and muscle GLUT4 KO mice before and after development of diabetes. Insulin-stimulated whole body glucose uptake was decreased by 55% in muscle GLUT4 KO mice, an effect that could be attributed to a 92% decrease in insulin-stimulated muscle glucose uptake. Surprisingly, insulin's ability to stimulate adipose tissue glucose uptake and suppress hepatic glucose production was significantly impaired in muscle GLUT4 KO mice. To address whether these latter changes were caused by glucose toxicity, we treated muscle GLUT4 KO mice with phloridzin to prevent hyperglycemia and found that insulin-stimulated whole body and skeletal muscle glucose uptake were decreased substantially, whereas insulin-stimulated glucose uptake in adipose tissue and suppression of hepatic glucose production were normal after phloridzin treatment. In conclusion, these findings demonstrate that a primary defect in muscle glucose transport can lead to secondary defects in insulin action in adipose tissue and liver due to glucose toxicity. These secondary defects contribute to insulin resistance and to the development of diabetes.

Adipose Tissue↗

PubMed2001

[Cloning and sequence analysis of a pseudogene of liver regeneration augmenter in rats].

OBJECTIVE: To investigate the status of the augmenter of liver regeneration (ALR) in rat's genome. METHODS: Polymerase chain reaction (PCR) was used to amplify the genomic DNA of rat, with a set of specific primers designed according to the cDNA sequence of ALR. The products were ligated into pGEM Teasy vector. Two positive clones were sequenced separately. RESULTS: Two products were amplified from the rat's genome by PCR. After sequencing, one pseudogene was identified. The homology of the amino acid sequence between the ALR and its pseudogene was 88.8%. CONCLUSIONS: ALR pseudogene is found in rat's genome, implying that there is an ALR multigene family. This finding lays a foundation for further study of ALR molecular evolution mode.

Amino Acid Sequence↗

PubMed2001

[Cloning and sequence analysis of truncated S gene from circulation of patients with chronic hepatitis B virus infection].

OBJECTIVE: To find different mutated status of HBV DNA in circulation from chronic HBV patients. METHODS: Specially designed primers and polymerase chain reaction method were applied to amplify the whole S gene of HBV from the serum of 2 patients. After being sequenced, 4 clones were compared with HBV adr subtype (China strain) to identify the mutant sites. RESULTS: Sequencing results implied that there was a truncated large/middle S gene in the serum of the patients. Besides that, HBsAg and HBV DNA polymerase defective clones were also detected. CONCLUSIONS: Truncated middle S gene is found in the circulation of patients with chronical HBV infection, suggestive of a poor prognosis.

Cloning, Molecular↗

PubMed2001

Heparanase protein and gene expression in bladder cancer.

PURPOSE: We determined the association of heparanase protein and messenger (m)RNA expression with bladder cancer invasion and metastasis. MATERIALS AND METHODS: The expression of heparanase protein and mRNA was assessed by immunohistochemical staining and in situ hybridization, respectively, in 67 bladder cancer specimens resected at various stages of disease. To our knowledge this is the first systematic study of heparanase protein and mRNA expression in human bladder cancer. RESULTS: The expression of heparanase protein in muscular invasive bladder cancer was significantly higher than in superficial cancer (68% versus 19%, p = 0.0001). It was higher in the primary tumor of patients with lymph node metastatic cancer than those with nonmetastatic cancer (80% versus 37%, p = 0.0006). In high grade disease it was significantly higher than in low grade disease (79% versus 29%, p = 0.0001). The expression of heparanase mRNA was also significantly higher in stage pT3 or greater than in stage pT2 or less bladder cancer (96% versus 33%, p = 0.0003). In metastatic N+ cases it was significantly higher than in nonmetastatic bladder cancer (93% versus 46%, p = 0.0037). The heparanase gene and protein showed similar patterns of expression in bladder cancer. CONCLUSIONS: Our study implies that the expression of heparanase protein and mRNA is associated with bladder cancer invasion and metastasis, and heparanase may have a role in disease progression.

Adult↗

PubMed2001

[Treatment of severe hepatitis with artificial liver support system and liver transplantation].

OBJECTIVE: To observe and investigate the efficacy of the hybrid artificial liver support system plus liver transplantation in the treatments of patients with severe viral hepatitis. METHODS: Eight severe viral hepatitis patients with metaphase and advanced stage liver failure received the artificial liver support using a self-command extracorporeal hybrid artificial liver support system and orthotopic liver transplantation after the artificial support for 3-14 days. RESULTS: The liver failure of the 8 patients was controlled by the hybrid artificial liver support effectively. All patients were successfully bridged to orthotopic liver transplantation. Four out of the eight patients survived after transplantation. Four patients died of pulmonary infection or hepatorenal syndrome. CONCLUSIONS: Artificial liver support system combined with liver transplantation can be regarded as an efficient measure for the treatment of metaphase and advanced stage patients of severe viral hepatitis.

Adult↗

PubMed2001

The use of FISH in chromosomal localization of transgenes in rice.

Chromosomal location and local chromatin structure are thought to play important roles in the stability of transgene expression. Fluorescence in situ hybridization (FISH) is a cytogenetic technique that allows the localization of specific DNA sequences on chromosomes. It provides an excellent means to analyze the chromosomal environment of integrated transgenes, helping to assess the effect of position on gene expression. FISH analyses have been conducted on nuclear chromosomal DNA at metaphase, interphase, meiotic prophase (pachytene) and on extended chromatin fibers (DNA fiber-FISH) and naked DNA molecules. Despite the small size of rice chromosomes, FISH has been successfully accomplished to detect unique and repetitive DNA sequences. A detailed FISH procedure for the detection of small and single copy transgenes within the rice genome is described and the application of FISH to evaluate chromosomal location and the local chromatin structure of transgenes as parameters that could affect their expression is discussed.

Chromosome Mapping↗

PubMed2001

[Effects of human immunodeficiency virus infection on pregnancy outcome].

OBJECTIVE: To investigate the effects of human immunodeficiency virus (HIV) infection on the pregnancy outcome and the incidence of vertical transmission in HIV-positive pregnant women. METHOD: 86 cases of HIV-positive pregnant women and their infants were evaluated retrospectively, and HIV antibody in peripheral blood was detected using enzyme linked immunosorbent assay (ELISA). RESULTS: Compared with normal control group, the incidences of abortion, preterm birth, low birth weight and small for gestational age babies were 9.3%, 14.0%, 16.3% and 10.5%, respectively (P < 0.05); the occurrence of conditional infections of reproductive tract was also higher (P < 0.05); and the incidence of vertical transmission was 12.8% (P < 0.01). CONCLUSIONS: HIV infection in pregnant women markedly increases the risks of abortion, preterm birth, low birth weight and small for gestational age babies, and elevates the incidence of conditional infections of reproductive tract. The incidence of vertical transmission was 12.8%. These data support that it is very important to provide prenatal care to HIV-infected pregnant women and prevent pregnant women from HIV infection.

Adolescent↗

PubMed2001

[Hepatic artery and portal vein dual perfusion chemotherapy in combination with injection of lipiodol-ethanol in treatment of advanced primary hepatocellular carcinoma].

OBJECTIVE: To investigate the therapeutic effects of hepatic artery and portal vein dual perfusion chemotherapy (AVPC) in combination with intratumoral injection of lipiodol-ethanol (IILE) on advanced primary hepatocellular carcinoma (PHC). METHODS: A total of 138 patients with pathologically proven and unresectable PHC were divided into two groups. In group A (n = 80), the patients were treated with PVPC through a hypodermic implanted drug delivery pump. In group B (n = 58), the patients were treated with PVPC + IILE. RESULTS: The total effective rate was 12.6% and 25.9% in group A and group B, respectively. There was a significant difference between the two groups (P < 0.05). The secondary resectable rate was 2.5% and 12.1% in group A and group B, respectively (P < 0.05). The half-, 1- and 2-year survival rates were 56.3%, 45.0% and 21.2% in group A but 81.0%, 61.2% and 39.6% in group B, respectively. There were significant differences bet ween the two groups (P < 0.05). However, there was no marked difference in incidence rate of complications between the two groups (P > 0.05). CONCLUSION: The therapeutic effect of AVPC + IILE on advanced PHC is better than that of PVPC alone.

Adult↗

PubMed2001

[Value of 18F-fluorodeoxyglucose positron emission tomography imaging in staging of non-small cell lung cancer].

OBJECTIVE: To evaluate the accuracy and value of fluorine desoxy-glucose Positron emission tomography (FDG PET) imaging in the staging of non-small cell lung cancer (NSCLC). METHODS: A retrospective analysis of 82 patients with NSCLC confirmed by pathological examination was made to study the staging of whole-body FDG PET scanning compared with computerized tomography (CT). RESULTS: The intake of FDG increased in the lung and metastatic foci among all 82 NSCLC patients. Whole-body PET scanning showed concentrated FDG in the 41 NSCLC patients with extrathoracic metastasis. The sensitivity and specificity of FDG PET in prediction of metastasis of mediastinal lymph nodes in patients with lung cancer were 94.4% and 100% respectively. The accuracy of PET scanning in staging of NSCLC was 95.2% in 42 patients who underwent operation after PET imaging. 37 NSCLC patients (45.1%) were restaged after the whole-body FDG PET scanning and their treatment programs were changed. CONCLUSION: PET is more advantageous in pre-operational staging of NSCLC than other conventional imaging techniques, such as CT. For accurate positioning, PET should be combined with anatomical imaging techniques.

Adult↗

PubMed2001

Characterization of hemagglutinin gene of influenza A virus subtype H9N2.

OBJECTIVE: To determine the origin of human influenza A (H9N2) virus and the relationship among H9N2 strains isolated from different hosts, on the basis of molecular biology. METHODS: Viruses were passed in embryonated hen eggs, and virion RNA was extracted from allantoic fluid and reverse transcribed to synthesize cDNA. cDNA was amplified by PCR and the PCR product was purified with a purification kit. Afterwards RNA sequence analysis was performed by dideoxynucleotide chain termination and a cloning method. Finally, phylogenetic analysis of the sequencing data was performed with MegAlign (version 1.03) and Editseg (version 3.69) softwares. RESULTS: The amino acid sequences at the cleavage site between HA1 and HA2 domains of H9N2 viruses isolated in China are R-S-S-R. One pigeon strain contains seven potential glycosylation sites on the HA protein molecule, while all others have eight. There are 2 to 15 differences of amino acid sequences distributed at 24 different positions on the HA protein molecules among six H9N2 viruses. The H9N2 viruses with multiple lineages of HA genes were co-circulating in China recently. CONCLUSION: The highest possibility is that human influenza A (H9N2) virus was derived from Chicken H9N2 virus, and not derived from pigeon H9N2 virus. However, it is still unknown whether the H9N2 virus could transmit from person to person. The H9N2 viruses with multiple lineages of HA genes are co-circulating in China.

Amino Acid Sequence↗