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Biomedical subjects

Yong Jiang

Publications and source records attributed to Yong Jiang.

At least 55 records · Page 3Linked to original sources
PubMed2005

Distinct transcriptional control mechanisms of killer immunoglobulin-like receptors in natural killer (NK) and in T cells.

Killer immunoglobulin-like receptors (KIR) are expressed by natural killer (NK) cells and by subsets of CD4+ and CD8+ T cells, which are therefore thought to be subject to similar regulatory mechanisms. Here, we show that the transcriptional machinery to express KIR is limited to NK and T cells; however, the KIR transcriptional control differs between these two types of lymphocytes. T cells selectively express transcriptional activators binding to positions -52 to -61 of the KIR promoter, whereas an AML site around position-98 is relevant for transcription in NK cells. Although KIR expression is restricted to subsets of memory T cells, our studies demonstrate that transcriptional activators for KIRs are not acquired during T cell differentiation but are already present in naïve T cells, suggesting a basic role of KIRs in T cell biology. We suggest that the regulated expression of KIRs in T cells profoundly influences peripheral tolerance and antigen-specific immune responses.

Base Sequence↗
PubMed2005

Characterization of cytokine/chemokine profiles of severe acute respiratory syndrome.

RATIONALE: There is currently no optimal treatment or effective drug for severe acute respiratory syndrome (SARS), because the immunopathologic mechanism is poorly understood. OBJECTIVES: To explore the immune mechanism underlying the pathogenesis of SARS, we studied the expression profile of cytokines/chemokines in the blood and the immunopathology of the lung and lymphoid tissues. METHODS: Fourteen cytokines/chemokines in the blood of 23 patients with SARS were dynamically screened, using a bead-based multiassay system. Reverse transcription-polymerase chain reaction was performed to amplify mRNA. Histopathology of the lung and lymphoid tissues at autopsy was examined, using methods of immunohistochemistry and double immunofluorescence staining. MAIN RESULTS: Interferon-inducible protein-10 (IP-10) was markedly elevated in the blood during the early stage of SARS, and remained at a high level until convalescence. Moreover, IP-10 was highly expressed in both lung and lymphoid tissues, where monocyte-macrophage infiltration and depletion of lymphocytes were observed. The levels of interleukin-6, interleukin-8, and monocyte chemoattractant protein-1 were concomitantly increased in the blood of the patients with superinfection, and the mRNAs for these cytokines were also increased in lung tissues. CONCLUSIONS: Induction of IP-10 is a critical event in the initiation of immune-mediated acute lung injury and lymphocyte apoptosis during the development of SARS. Superinfection after the immune injury is the main cause of death. The prompt elevation of interleukin-6, interleukin-8, and monocyte chemoattractant protein-1 is a sign of superinfection, indicating a high risk of death.

Adult↗
PubMed2005

Nonequivalence of the nucleotide binding domains of the ArsA ATPase.

The arsRDABC operon of Escherichia coli plasmid R773 encodes the ArsAB pump that catalyzes extrusion of the metalloids As(III) and Sb(III), conferring metalloid resistance. The catalytic subunit, ArsA, is an ATPase with two homologous halves, A1 and A2, connected by a short linker. Each half contains a nucleotide binding domain. The overall rate of ATP hydrolysis is slow in the absence of metalloid and is accelerated by metalloid binding. The results of photolabeling of ArsA with the ATP analogue 8-azidoadenosine 5'-[alpha-(32)P]-triphosphate at 4 degrees C indicate that metalloid stimulation correlates with a >10-fold increase in affinity for nucleotide. To investigate the relative contributions of the two nucleotide binding domains to catalysis, a thrombin site was introduced in the linker. This allowed discrimination between incorporation of labeled nucleotides into the two halves of ArsA. The results indicate that both the A1 and A2 nucleotide binding domains bind and hydrolyze trinucleotide, even in the absence of metalloid. Sb(III) increases the affinity of the A1 nucleotide binding domain to a greater extent than the A2 nucleotide binding domain. The ATP analogue labeled with (32)P at the gamma position was used to measure hydrolysis of trinucleotide at 37 degrees C. Under these catalytic conditions, both nucleotide binding domains hydrolyze ATP, but hydrolysis in A1 is stimulated to a greater degree by Sb(III) than A2. These results suggest that the two homologous halves of the ArsA may be functionally nonequivalent.

Adenosine Triphosphate↗
PubMed2005

Australopithecus anamensis: a finite-element approach to studying the functional adaptations of extinct hominins.

Australopithecus anamensis is the stem species of all later hominins and exhibits the suite of characters traditionally associated with hominins, i.e., bipedal locomotion when on the ground, canine reduction, and thick-enameled teeth. The functional consequences of its thick enamel are, however, unclear. Without appropriate structural reinforcement, these thick-enameled teeth may be prone to failure. This article investigates the mechanical behavior of A. anamensis enamel and represents the first in a series that will attempt to determine the functional adaptations of hominin teeth. First, the microstructural arrangement of enamel prisms in A. anamensis teeth was reconstructed using recently developed software and was compared with that of extant hominoids. Second, a finite-element model of a block of enamel containing one cycle of prism deviation was reconstructed for Homo, Pan, Gorilla, and A. anamensis and the behavior of these tissues under compressive stress was determined. Despite similarities in enamel microstructure between A. anamensis and the African great apes, the structural arrangement of prismatic enamel in A. anamensis appears to be more effective in load dissipation under these compressive loads. The findings may imply that this hominin species was well adapted to puncture crushing and are in some respects contrary to expectations based on macromorphology of teeth. Taking together, information obtained from both finite-element analyses and dental macroanatomy leads us to suggest that A. anamensis was probably adapted for habitually consuming a hard-tough diet. However, additional tests are needed to understand the functional adaptations of A. anamensis teeth fully.

Adaptation, Physiological↗
PubMed2005

Spatial heterogeneity of DTPA-extractable zinc in cultivated soils induced by city pollution and land use.

The spatial heterogeneity of DTPA-extractable zinc in the cultivated soils of Shenyang suburbs in Liaoning Province of China was investigated, and its map was drawn by the methods of geostatistics combined with geographic information system. The data of soil DTPA-extractable zinc fitted normal distribution after logarithm transformation, and its semivariogram fitted a spherical model. The semivariogram indicated that the spatial dependence of soil DTPA-extractable zinc content was moderate, with the spatial dependence range of 1.69 km and the fractal dimension of 1.96. Stochastic factors contributed to 49.9% of the spatial variability, while structural factors contributed to 50.1% of it. The spatial heterogeneity of soil DTPA-extractable zinc shown by a kriged interpolation map was deeply influenced by stochastic factors such as city pollution, land use pattern and crop distributions. For example, the average content of Zn in vegetable garden soils was 2.5-4 times as much as in their originated soils, and was lower in paddy soils than in their originated soils. The areas with a higher content of soil DTPA-extractable zinc appeared in the near suburbs and the riverside along Hunhe River and the wastewater drainage of Xihe River, and the extremely high values in the near suburb of the city's residential area were a striking feature, indicating the key role of city pollution in the spatial heterogeneity of soil DTPA-extractable zinc. When recorded in the form of a soil pollution map, the results of such a survey make it possible to identify the unusually polluted areas, and to provide more information for precise agriculture and environmental control.

Agriculture↗
PubMed2005

Surgical management of thymic epithelial tumors: a retrospective review of 204 cases.

BACKGROUND: Thymic epithelial tumors consist of a series of neoplasm that differ morphologically and biologically. Management strategy for these tumors remains controversial. METHODS: We retrospectively reviewed 204 thymic epithelial tumors surgically treated during the period of 1970 to 1995, and we reexamined the histologic specimens using the current World Health Organization classification. RESULTS: One hundred eighty patients (88.2%) underwent complete resections, 17 (8.3%) received partial resections, and 7 (3.4%) received biopsies only. The complete resection rate of stages I and II tumors was significantly higher than stages III and IV tumors (98.2% vs 76.6%; p < 0.001). Twenty-four patients (11.8%) experienced 29 events of complications postoperatively, including 11 events of myasthenia gravis crisis. Myasthenia gravis, partial resection or biopsy, and stages III and IV were independent risk factors for postoperative complications. Fifteen patients (7.4%) died during hospital stays, including 6 patients from myasthenia crisis. Partial resection or biopsy and myasthenia gravis were independent risk factors for postoperative mortality. There were significantly more stage I and stage II cases in histologic types A, AB, and B1 tumors than in B2, B3, and C tumors (87.6% vs 26.4%; p < 0.001), and their complete resection rate was significantly higher than the latter group (98.9% vs 78.3%; p < 0.001). The 5-year and 10-year survival rates were 63.2% and 50.4%, respectively. Masaoka stages III and IV, histologic types B2, B3, and C, and incomplete resection were independent risk factors for poor prognosis. CONCLUSIONS: Complete resection remains the hope of cure for thymic epithelial tumors. The treatment strategy should be based on the current World Health Organization histologic classification and the Masaoka staging system.

Adolescent↗
PubMed2005

Xanthone glycosides from Polygala tenuifolia and their conformational analyses.

Seven xanthone glycosides were isolated from the cortexes of Polygala tenuifolia, and their structures were identified as polygalaxanthones VIII-XI (1-4), sibiricoxanthone B (5), 7-O-methylmangiferin (6), and lancerin (7), on the basis of spectroscopic analyses. Compounds 1-4 are new xanthone glycosides, and compounds 4 and 5 exist as rotamers. To explain this phenomenon, conformational analyses were performed on compounds 4 and 5 and other compounds with similar skeletons that were isolated from P. tenuifolia.

Glycosides↗
PubMed2005

Triterpene saponins from the leaves of Ilex kudingcha.

Nine new triterpene saponins, ilekudinosides K-S (1-9), and eight known triterpene saponins were isolated from the 70% ethanol extract of the leaves of Ilex kudingcha. The new saponins were characterized as 3-O-alpha-L-rhamnopyranosyl(1-->2)-beta-D-glucopyranosyl-alpha-kudinlactone (1), 3-O-beta-D-glucopyranosyl(1-->3)-alpha-L-arabinopyranosyl-beta-kudinlactone (2), 3-O-alpha-L-rhamnopyranosyl(1-->2)-alpha-L-arabinopyranosyl-gamma-kudinlactone (3), 3-O-beta-D-glucopyranosyl(1-->2)-beta-D-glucopyranosyl-alpha-kudinlactone (4), 3-O-beta-D-glucopyranosyl(1-->2)-alpha-L-arabinopyranosyl-alpha-kudinlactone (5), 3-O-beta-D-glucopyranosyl(1-->3)-alpha-L-arabinopyranosyl-alpha-kudinlactone (6), 3-O-alpha-L-rhamnopyranosyl(1-->2)-beta-D-glucopyranosyl-beta-kudinlactone (7), 3-O-alpha-L-rhamnopyranosyl(1-->2)-alpha-L-arabinopyranosyl-beta-kudinlactone (8), and 3-O-alpha-L-rhamnopyranosyl(1-->2)-beta-D-glucopyranosyl-gamma-kudinlactone (9), respectively. The structures and stereochemistry of compounds 1-9 were elucidated by spectroscopic data interpretation and chemical degradation.

Drugs, Chinese Herbal↗
PubMed2005

Sorting out bioactivity in flavonoid mixtures.

Natural polyphenolic compounds, including flavonoids, which are synthesized by plants, have repeatedly been linked to multiple health benefits, but specific bioactive compounds or individualized roles have been difficult to interpret or to assign. This limitation has prevented the development of robust dietary recommendations. This paper describes a plant-cell-culture production approach that provides uniform yields of abundant natural mixtures of flavonoids from small molecules to high molecular weight oligomers and polymers. The flavonoids correspond to compounds produced in nature by the same plant genotypes; but, through elicitation tactics, the levels and the profiles of the flavonoid yield can be enhanced, and isolation from cell cultures is more rapid and streamlined than isolation from in vivo plant tissues. Introduction of (14)C sucrose to the cell-culture medium enabled the recovery and the identification of biolabeled flavonoid mixtures, which could be easily tracked in serum of rats after gavage. The biolabeled materials are now being investigated to determine tissue localization, structures of bioactive components, and the interactions between flavonoid components that contribute to bioactive potential.

Animals↗
PubMed2005

Four new phenones from the cortexes of Polygala tenuifolia.

From the 95% EtOH extract of the cortexes of Polygala tenuifolia, four new phenones and three known xanthones were isolated. The structures of the four new phenones were identified as 4-O-[alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranosyl]-2-hydroxyl-6-methoxybenzophenone (tenuiphenone A, 1), 3,5-di-C-beta-glucopyranosyl-2,4,6,3'-tetrahydroxybenzophenone (tenuiphenone B, 2), 2',4',6'-trihydroxyphenyl-(24Z)-triacontene-1-one (tenuiphenone C, 3), 2',4',6'-trihydroxyphenyl-(26Z)-dotriacontene-1-one (tenuiphenone D, 4) respectively, on the basis of spectroscopic analyses. The isolation of 1 and 2 supplied an evidence for the hypothesis that xanthone was biosynthesized from benzophenone in the plants.

Benzophenones↗
PubMed2005

[Construction of GFP-AWP1 fusion gene vector and its expression in 293 cells].

OBJECTIVE: To construct green fluorescent protein (GFP)-AWP1 (a novel human protein associated with protein kinase C-related kinase 1) fusion gene vector for observing the expression and localization of AWP1 in 293 cells. METHODS: The coding region in AWP1 cDNA was amplified by RT-PCR from human endothelial cell line ECV304 and recombined into pEGFP-C2 plasmid expressing GFP. After identification with restriction endonucleases and sequence analysis, the recombinant plasmid was transfected into 293 cells with the cationic liposome DOTAP as the transfection reagent. The expression and localization of AWP1 were observed under a fluorescence microscope. RESULTS: Restriction endonuclease assay and sequence analysis verified the successful construction of the recombinant vector pEGFP-C2/AWP1, and GFP-AWP1 fusion protein was highly efficiently expressed in 293 cells. Under fluorescent microscope, green fluorescence was seen homogeneously distributed in the entire cell body of the cells transfected by the empty vector pEGFP-C2, but diffusely in the cytoplasm of the cells transfected by the recombinant vector pEGFP-C2/AWP1. CONCLUSION: GFP-AWP1 fusion gene vector is successfully constructed and the fusion protein expressed in the cytoplasm of 293 cells.

Cell Line↗
PubMed2005

[Construction and expression of green fluorescent protein fusion vector of p38 regulated/activated protein kinase].

OBJECTIVE: To construct the expression vector of p38 regulated/activated protein kinase (PRAK) fused to green fluorescent protein which is capable of expression in mammalian cells. METHODS: PRAK with His-tag in pET-14b expression vector was subcloned into the green fluorescent protein vector pEGFP-C2. The recombinant vector was then transfected into HeLa cells, followed by observation of the cells with fluorescent microscope. RESULTS: Identification by enzyme digestion, PCR and sequencing confirmed successful construction of the recombinant vector, which was highly expressed in HeLa cells. Green fluorescence of the fusion protein EGFP-PRAK was observed mainly in the cell nuclei. CONCLUSION: The expression vector of PRAK fused to green fluorescent protein is successfully constructed and expressed in mammalian cells, which may facilitate the study of intracellular localization and translocation of PRAK.

Gene Expression↗
PubMed2005

Effect of free-air CO2 enrichment on nematode communities in a Chinese farmland ecosystem.

At a rice-wheat rotational free-air CO2 enrichment( FACE) platform, the effect of elevated atmospheric CO2 on soil nematode communities in a farmland ecosystem was studied. Wheat plots were exposed to elevated atmospheric CO2 (ambient 370 microl/L + 200 microl/L). 32 families and 40 genera of nematode were observed in soil suspensions during the study period. Under FACE treatment, the numbers of total nematodes, bacterivores and fungivores exhibited an increasing trend. Because of the seasonal variation of soil temperature and moisture, the effect of elevated atmospheric CO2 on soil nematodes was only observed under favorable conditions. The response of nematode communities to elevated atmospheric CO2 may indicate the change of soil food web.

Agriculture↗
PubMed2005

[Hypothesis on generating and tracer gas study regarding transmission of severe acute respiratory syndrome through ventilation system in a general hospital].

OBJECTIVE: By measuring airflow and ventilation distribution of ward building, to explore and verify the hypothesis of airborne transmission and risk factor of severe acute respiratory syndrome (SARS) nosocomial infection. METHODS: Tracer gas (perfume of plant oil) was emitted to the bathroom of wards when SARS index patient lived. Six different experimental situations were designed to control the status of exhaust fan in bathrooms, exhaust fan in the top of building and fresh air exchange system. The concentration of perfume was separately measured by 4 groups of lab workers and recorded blindly by the scores of "tenth degree". RESULTS: Tracer gas was detected from the wards of 8th to 13th floor. CONCLUSION: Architecture and ventilation system of the inpatient building in the hospital contributed to the aerodynamic condition of SARS nosocomial infection through airborne transmission. The distribution of tracer gas in the wards was associated with SARS patients in this building. It was possible that SARS could have been transmitted to for distance by aerosol or other carriers.

Air Microbiology↗
PubMed2005

[Prokaryotic expression and activity identification of recombinant human soluble receptor for advanced glycation end products].

OBJECTIVE: To construct a eukaryotic expression vector for His-tagged human soluble receptor for advanced glycation end products (hsRAGE), and study the function and biological activity of the fusion protein. METHODS: The coding sequence of hsRAGE was amplified from the recombinant pCI-neo/RAGE by PCR method. The fragment was cloned into pET-14b vector and identified by digestion with restriction enzymes and sequence analysis. After transformation of the vector into E. coli BL21(DE3), the fusion protein was expressed successfully in response to IPTG induction in the form of inclusion body. After extraction from the bactrerial cells and washing, the fusion protein was dissolved in 8 mol/L urea and purified using immobilized metal ion affinity chromatography. Renaturing of the fusion protein occurred after gradually removal of the denaturants by dialysis. The protein was subsequently identified by Western blotting, enzyme-linked immunosorbent assay (ELISA) and blockade experiments in the endothelial cells. RESULTS: The recombinant hsRAGE/pET-14b was verified by enzyme digestion and sequencing. A fusion protein with a molecular weight of about 45 kD was purified, which could interact with anti-RAGE antibody and AGE and block AGE-induced nuclear factor (NF)-kB activation in the endothelial cells. CONCLUSIONS: His-hsRAGE fusion protein has been cloned, expressed and purified successfully and identified to possess immunogenicity, binding activity to AGE and blocking effect on AGE-RAGE.

Genetic Vectors↗