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Biomedical subjects

Qing Zhang

Publications and source records attributed to Qing Zhang.

231 records · Page 13Linked to original sources
PubMed2002

Genome scale comparison of Mycobacterium avium subsp. paratuberculosis with Mycobacterium avium subsp. avium reveals potential diagnostic sequences.

The genetic similarity between Mycobacterium avium subsp. paratuberculosis and other mycobacterial species has confounded the development of M. avium subsp. paratuberculosis-specific diagnostic reagents. Random shotgun sequencing of the M. avium subsp. paratuberculosis genome in our laboratories has shown >98% sequence identity with Mycobacterium avium subsp. avium in some regions. However, an in silico comparison of the largest annotated M. avium subsp. paratuberculosis contigs, totaling 2,658,271 bp, with the unfinished M. avium subsp. avium genome has revealed 27 predicted M. avium subsp. paratuberculosis coding sequences that do not align with M. avium subsp. avium sequences. BLASTP analysis of the 27 predicted coding sequences (genes) shows that 24 do not match sequences in public sequence databases, such as GenBank. These novel sequences were examined by PCR amplification with genomic DNA from eight mycobacterial species and ten independent isolates of M. avium subsp. paratuberculosis. From these analyses, 21 genes were found to be present in all M. avium subsp. paratuberculosis isolates and absent from all other mycobacterial species tested. One region of the M. avium subsp. paratuberculosis genome contains a cluster of eight genes, arranged in tandem, that is absent in other mycobacterial species. This region spans 4.4 kb and is separated from other predicted coding regions by 1,408 bp upstream and 1,092 bp downstream. The gene upstream of this eight-gene cluster has strong similarity to mycobacteriophage integrase sequences. The GC content of this 4.4-kb region is 66%, which is similar to the rest of the genome, indicating that this region was not horizontally acquired recently. Southern hybridization analysis confirmed that this gene cluster is present only in M. avium subsp. paratuberculosis. Collectively, these studies suggest that a genomics approach will help in identifying novel M. avium subsp. paratuberculosis genes as candidate diagnostic sequences.

Animals↗
PubMed2002

Genotypic diversity of clinical Actinomyces species: phenotype, source, and disease correlation among genospecies.

We determined the frequency distribution of Actinomyces spp. recovered in a routine clinical laboratory and investigated the clinical significance of accurate identification to the species level. We identified 92 clinical strains of Actinomyces, including 13 strains in the related Arcanobacterium-Actinobaculum taxon, by 16S rRNA gene sequence analysis and recorded their biotypes, sources, and disease associations. The clinical isolates clustered into 21 genogroups. Twelve genogroups (74 strains) correlated with a known species, and nine genogroups (17 strains) did not. The individual species had source and disease correlates. Actinomyces turicensis was the most frequently isolated species and was associated with genitourinary tract specimens, often with other organisms and rarely with inflammatory cells. Actinomyces radingae was most often associated with serious, chronic soft tissue abscesses of the breast, chest, and back. Actinomyces europaeus was associated with skin abscesses of the neck and genital areas. Actinomyces lingnae, Actinomyces gravenitzii, Actinomyces odontolyticus, and Actinomyces meyeri were isolated from respiratory specimens, while A. odontolyticus-like strains were isolated from diverse sources. Several of the species were commonly coisolated with a particular bacterium: Actinomyces israelii was the only Actinomyces spp. coisolated with Actinobacillus (Haemophilus) actinomycetemcomitans; Actinomyces meyeri was coisolated with Peptostreptococcus micros and was the only species other than A. israelii associated with sulfur granules in histological specimens. Most genogroups had consistent biotypes (as determined with the RapID ANA II system); however, strains were misidentified, and many codes were not in the database. One biotype was common to several genogroups, with all of these isolates being identified as A. meyeri. Despite the recent description of new Actinomyces spp., 19% of the isolates recovered in our routine laboratory belonged to novel genospecies. One novel group with three strains, Actinomyces houstonensis sp. nov., was phenotypically similar to A. meyeri and A. turicensis but was genotypically closest to Actinomyces neuii. A. houstonensis sp. nov. was associated with abscesses. Our data documented consistent site and disease associations for 21 genogroups of Actinomyces spp. that provide greater insights into appropriate treatments. However, we also demonstrated a complexity within the Actinomyces genus that compromises the biochemical identification of Actinomyces that can be performed in most clinical laboratories. It is our hope that this large group of well-defined strains will be used to find a simple and accurate biochemical test for differentiation of the species in routine laboratories.

Actinomyces↗
PubMed2002

Targeted disruption of the melanin-concentrating hormone receptor-1 results in hyperphagia and resistance to diet-induced obesity.

The hypothalamic neuropeptide melanin-concentrating hormone (MCH) has been implicated in a variety of physiological functions including the regulation of feeding and energy homeostasis. Two MCH receptors (MCHR1 and MCHR2) have been identified so far. To decipher the functional role of the MCH receptors, we have generated and phenotypically characterized mice rendered deficient in MCHR1 expression by homologous recombination. Inactivation of MCHR1 results in mice (MCHR1-/-) that are resistant to diet-induced obesity. With a high-fat diet, body fat mass is significantly lower in both male (4.7 +/- 0.6 g vs. 9.6 +/- 1.2 g) and female (3.9 +/- 0.2 vs. 5.8 +/- 0.5 g) MCHR1-/- mice than that of the wild-type control (P < 0.01), but the lean mass remains constant. When normalized to body weight, female mice are hyperphagic, and male mice are hyperphagic and hypermetabolic, compared with wild-type mice. Consistent with the lower fat mass, both leptin and insulin levels are significantly lower in male MCHR1-/- mice than in the wild-type controls. Our data firmly establish MCHR1 as a mediator of MCH effects on energy homeostasis and suggest that inactivation of MCHR1 alone is capable to counterbalance obesity induced by a high-fat diet.

Adipose Tissue↗
PubMed2002

Metabolism of constituents in Huangqin-Tang, a prescription in traditional Chinese medicine, by human intestinal flora.

In the course of studies on the metabolism of active components of Huangqin-Tang by human intestinal flora (HIF), Huangqin-Tang and all individual herbs in the decoctions were incubated with a human fecal suspension separately. By using a high-performance liquid chromatographic (HPLC) method which was previously established in our laboratory, the metabolites in both the compound prescription and all the single herb decoctions were identified and determined both qualitatively and quantitatively. We found that the constituents of Huangqin-Tang, incluing baicalin (baicalein 7-glucuronide; BG), wogonoside (wogoninoglucuronide; WG), oroxylin-A-glucuronide (OG) from Scutellariae Radix, paeoniflorin (PF) from Paeoniae Radix, liquiritin (liquiritigenin 4'-O-glucoside; LG), isoliquirtin (isoliquiritigenin 4-glucoside; ILG) and glycyrrhizic acid (GL) from Glycyhhizea Radix, were converted to their metabolites baicalein (B), wogonin (W), oroxylin-A (O), paeonimetabolin-I (PM-I), liquiritigenin (L), isoliquiritigenin (IL) and glycyrrhetinic acid (GA) by HIF. The contents of the metabolites in Huangqin-Tang and in each single herb decoction increased significantly after incubation with intestinal flora. Comparing with single herb decoctions, the transformation of BG, WG, OG, LG and ILG in the compound prescription was promoted, however, that of PF and GL was inhibited. All the results suggested that the glycosides of many medicinal herbs could be converted to aglycones by HIF, and the metabolism of most glycosides was improved in the compound prescription.

Area Under Curve↗
PubMed2002

[The effects of C2 gene on growth of gastric cancer cells].

OBJECTIVE: To investigate the effect of a newly cloned full length gene, C2 gene, which encodes human eukaryotic translation initiation factor, on growth of gastric cancer cells. METHODS: A constructed eukaryotic vector carrying the full length of C2 gene was amplified, purified and transfected into gastric cancer cell line-SGC 7901. Expression of C2 protein was examined with fluorescence activated cell sorting (FACS) and immunohistochemical staining. Growth curve of the C2 gene transfected gastric cancer cells was drawn with the results of MTT assay and cell count. RESULTS: FACS and immunohistochemical staining showed that C2 protein was expressed highly and stably in the C2 gene transfected cells. The growth curve of the C2 gene transfected cells by both MTT and cell count showed that the C2 gene transfected cells had less proliferation than the control cells. The growth cycle of transfected cells was 11 days, while the control was 7 days. CONCLUSION: C2 gene transfection may inhibit the growth of human gastric cancer cells. It might become a potential inhibitor of gastric cancer in the level of protein translation initiation.

Cell Division↗
PubMed2002

Studies on hypokalemia induced by trimethyltin chloride.

OBJECTIVES: To determine the possible relationship between plasma potassium concentration and severity of acute trimethyltin chloride (TMT) poisoning and to assess the mechanism of TMT induced hypokalemia. METHODS: SD rats were treated with various dosages of TMT (i.p.). All the indices were measured and analysed for determining their possible relations with plasma K+. RESULTS: With increase of dosage, the plasma K+ level dropped rapidly, and deaths appeared more quickly. The LD50 of TMT (i.p.) was 14.7 mg/kgbw. In the low dosage group (10 mg/kgbw), the plasma K+ level dropped slowly with the lowest dosage on day 6 (4.85 mmol/L). It rose again on day 11 (5.06 mmol/L), and recovered on day 28. The poisoning signs corresponded with decline of the span of K+ level. The plasma Na+ level dropped half an hour after TMT treatment, but recovered 24 h later. In the high dosage group (46.4 mg/kgbw), the levels of plasma K+ and Na+ fell rapidly within half an hour (P < 0.05), the intracellular potassium concentration of RBC did not decrease obviously (P > 0.05), the activities of Na(+)-K(+)-ATPase and Mg(2+)-ATPase in RBC membrane were depressed remarkably (P < 0.01, P < 0.05, respectively), the plasma aldosterone concentrations rose as high as tenfold (P < 0.01), the arterial blood pH fell from 7.434 to 7.258 (P < 0.01), pCO2 was raised from 29.62 to 45.33 mmHg (P < 0.01). In the 24 h urine test, when rats were treated with TMT (21.5 mg/kgbw, i.p.), urine volume, urinary potassium, sodium and chloride increased significantly in comparison with those in the controls (P < 0.01). CONCLUSION: TMT could induce hypokalemia in SD rats. The available evidence suggests that TMT can induce acute renal leakage of potassium. At the same time, a significant rise of plasma aldosterone may play an important role in promoting potassium leakage from kidney to result in severe hypokalemia with inhaling acid-base abnormalities produced, which aggravate the poisoning symptoms. In the end the rats would die of respiratory failure.

Animals↗
PubMed2002

[Survey on the utilization of narcotic analgesics].

UNLABELLED: To evaluate the prescription of narcotic analgesics by the medical staff of Nanfang Hospital. METHODS: Drug utilization index (DUI) was used to analyze the prescriptions of narcotic analgesics to both in- and out-patients in the year of 2000. RESULTS: Six kinds of narcotic analgesics were prescribed mostly to relieve renal biliary colic, cancer pain and cough in the year 2000 in Nanfang Hospital. DUI shows no abuses of narcotic analgesics. CONCLUSION: The utilization of narcotic analgesics in Nanfang Hospital is basically well justified.

Adolescent↗
PubMed2002

[Role of the three-dimensional distribution of abl and bcr genes in the formation of bcr/abl fusion gene in interphase neucleus].

OBJECTIVE: To explore the mechanism of bcr/abl fusion gene formation in view of its biological stereology. METHODS: Assisted by fluorescent in situ hybridization combined with confocal laser scanning microscopy, we observed the effect of gamma-ray exposure on three-dimensional distribution of bcr and abl genes in the interphase nucleus of IM-9 cell line. RESULTS: In interphase nuclei of IM-9 cells, abl and bcr genes retained their own definite distribution patterns that were dynamically and regularly modulated along with the phases of the cell cycle. gamma-ray exposure, however, produced shortened distances between the 2 genes. CONCLUSION: The accessibility of abl and bcr genes to each other in the interphase nuclei is one of the factors for bcr/acl fusion gene formation.

Cell Cycle↗
PubMed2002

[The change in IL-13 mRNA expression in rat lungs with acute pulmonary injury induced by lipopolysaccharide].

OBJECTIVE: To observe the change in IL-13 mRNA expression in rat lungs with acute lung injury (ALI) induced by lipopolysaccharide (LPS), so as to investigate the significance of anti-inflammatory mechanism in the development of ALI. METHODS: (1) Different doses (2 approximately 8 mg/kg) of LPS were injected via the tail vein to the rats to establish ALI model. (2) The IL-13 mRNA content in pulmonary tissue was determined by RT-PCR. RESULTS: (1) Different degrees of ALI was induced in the rats by different doses of LPS. ARDS was produced in the rats by LPS of 6 mg/kg. (2) The IL-13 mRNA expression in the pulmonary tissue could be enhanced by the induction of LPS, especially when its dose was larger than 6 mg/kg. CONCLUSION: (1) Rat ALI model could be produced by LPS injection via the tail vein. (2) LPS in dose of 6 mg/kg was the threshold for the production of rat ARDS. (3) The incidence of rat ARDS might be closely related to the enhanced expression of IL-13 mRNA in rat pulmonary tissue.

Acute Disease↗
PubMed2002

[Investigation on the relationship of occlusal force to formation of wedge-shaped defects].

OBJECTIVE: To clinically investigate and identify the occlusal force as one of factors relative to formation of wedge-shaped defects. METHODS: 123 subjects, selected from a group of middle-aged and elderly people in an urban area were divided into four groups: control, light, middle and severe group according to the severity of wedge-shaped defects. Cuspid, first and second premolars, and first molar in maxilla were examined for occlusal force by occlusometer, and the peak value of occlusal contact strain on every maxillary tooth was studied by photocclusion. RESULTS: Significant reduce of occlusive force in the defected teeth was found than that of in the control teeth. The occlusal contact strain of first premolars with defects by photocclusion was statistically increased. The relative occlusal contact strain of first premolars and first molar of defects was higher than that of their proximate teeth. CONCLUSION: Occlusal force could have relation to the formation of wedge-shaped defects.

Adult↗
PubMed2002

[Changes of plasma interleukin-4, interleukin-10 and interleukin-13 in patients with acute respiratory distress syndrome].

OBJECTIVE: To explore the anti-inflammatory mechanisms of interleukin-4 (IL-4), interleukin-10 (IL-10) and interleukin-13 (IL-13) in acute respiratory distress syndrome (ARDS). METHODS: Enzyme-linked immunosorbent assay (ELISA) was employed to determine the plasma levels of IL-4, IL-10 and IL-13 in patients with ARDS (n = 22) and systemic inflammatory response syndrome (SIRS, n = 8). Ten normal subjects were enrolled as controls. RESULTS: The plasma levels of IL-4, IL-10 and IL-13 were (261 +/- 55) microg/L, (458 +/- 112) microg/L and (5.21 +/- 2.02) microg/L, respectively in patients with ARDS; (155 +/- 26) micro g/L, (260 +/- 54) microg/L and (1.69 +/- 0.39) microg/L respectively in patients with SIRS; and (43 +/- 13) microg/L, (135 +/- 15) microg/L and (0.33 +/- 0.10) microg/L, respectively in normal controls. They were significantly increased in patients with ARDS and SIRS as compared to normal controls, and the levels were higher in patients with ARDS than in patients with SIRS. CONCLUSIONS: Increased release of anti-inflammatory cytokines, such as IL-4, IL-10 and IL-13, may be one of the underlining mechanisms for the development of ARDS and SIRS.

Adult↗
PubMed2002

[Direct UV detection of glucose and its derivatives in capillary zone electrophoresis].

UV labeling detection has been commonly used to determine the association constants between lectins and saccharides, but the interaction is always between the labeled carbohydrates, rather than the truly underivatized carbohydrates, and lectins. In order to directly detect saccharides during the study on the interaction of glucose and its derivatives with lectins (e.g., concanavalin A), a capillary zone electrophoretic method with detection at a wavelength of 195 nm has been developed. The influences of various separation conditions including buffer concentration, pH and voltage were investigated. By using an uncoated silica capillary (50 microns i.d., 375 microns o.d., 48.5 cm of total length, and 44.0 cm to the detector) and 50 mmol/L Na2HPO(4)-50 mmol/L NaH2PO4 solution (near to the physiological pH of 7.4) as buffer, the underivatized sugars, including glucosamine, N-acetylglucosamine, glucose, and sodium gluconate, were sufficiently separated within 11 min at an applied voltage of 10 kV. On-column UV monitoring allowed the detection of these compounds at less than 4 mmol/L level, and quantification by the peak area method allowed reproducible determination of them at least at their respective concentration ranges. The method is characterized by its simplicity, rapidity, and reproducibility, and should be useful for the analysis of the interaction of glucose and its derivatives with lectins.

Concanavalin A↗
PubMed2002

[Intra-arterial thrombolysis in patients with acute ischemic stroke of the cervical internal carotid artery occlusive disease].

OBJECTIVE: To observe the safety and efficacy of local intra-arterial thrombolysis (LIT) in patients with acute ischemic stroke of cervical internal carotid artery occlusive disease. METHODS: 10 patients were treated by LIT. 2 of 10 patients were further treated by either angioplasty or endarterectomy. Primary neuroradiological assessment was performed with CT in all patients. Angiographic recanalization level was classified according to thrombolysis in myocardial infarction (TIMI) grades. Clinical outcome was classified as good for Modified Rankin Scale (MRS) scores of 0 to 3 and as poor for MRS scores of 4 to 6. RESULTS: Complete/partial recanalization after infusion was accomplished in 8 patients, seven of whom had good clinical outcome. Cerebral hemorrhage occurred in 2 of 10 patients. CONCLUSION: The results of this study suggest that LIT may be helpful to improve the outcome in patients with acute cervical internal carotid artery occlusive disease if it is performed within 6 hours of stroke onset.

Adolescent↗
PubMed2002

[Determination of anions in the products of ozonation of reactive dye by ion chromatography].

A method for the determination of anions in the degradation products of C. I. Reactive Red 120 by ozonation was investigated. The sample can be pretreated with a Dionex OnGuard P column, which has high selectivity for removing phenols, azo group-contaning compounds, aromatic carboxylic aicds etc. For the separation of organic and inorganic anions in the products, the anion exchange chromatograhy with gradient elution of NaOH was used. All the species were detected by both suppressed conductivity and UV absorbance detectors. The sulfate, oxalate, chloride, nitrate and formate could be identified even in very low concentration with ion chromatography, within 18 min, with the recoveries between 91.6% - 108.3%. The results indicate that the method is reliable, simple, rapid and especially sensitive. In combining with the determination results of conventional parameters of the solution of Reactive Red 120, a preliminary elucidation of the degradation mechanism

Anions↗