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Biomedical subjects

Q Xu

Publications and source records attributed to Q Xu.

At least 235 records · Page 13Linked to original sources
PubMed1999

[The clinical features of multiple-trauma patients APACHE II score system].

The clinical features of 76 multiple-trauma patients in the intensive care unit were observed with acute physiology and chronic health evaluation (APACHE II) system. The results showed that the mean value of APACHE II scores in 76 patients was 18.4; the mean duration of staying at the ICU was 91.5 hours. Six patients died in the ICU (7.9%), 13 patients were complicated with MODS (17.1%), and 10 patients developed ARDS (13.2%). As APAHCE II scores increased, the duration of the patient staying at the ICU lengthened and the mortality went up.

APACHE↗
PubMed1999

[Production and identification of anti-paraoxon monoclonal antibodies].

Paraoxon (E600) was conjugated to bovine serum albumin(BSA) or tachypleus tridentatus hemocyanin (TTH) by diazotization. Two hybridoma cell lines secreting monoclonal antibodies(McAb) against paraoxon have been established by fusing mouse myeloma cells and splenocytes from Balb/c mice immunized with E600-BSA. The chromosomes of the hybridoma cell 2B10 were analyzed. The immunoglobulin of the McAb was classified. The affinity and specificity of this antibody were determined. The hybridoma cells have fairly reserved the antibody-producing capacity after continuously growing or stored in liquid nitrogen for 10 weeks.

Animals↗
PubMed1999

[Free radicals on cataracts induced by sodium selenite studied by ESR and LPO].

We made a electron spin resonance (ESR) study on rat cataracts induced by Na2SeO3. A signal was detected at about g = 2.0026, and the content of electron spins (CES) in lens of rat administrated Na2SeO3 for a short time is higher than that of control significantly. At the late stage of cataracts, the content of CES was lower than normal level. The results of kinetics analysis showed that the CES grow up with the administration of Na2SeO3 and decays in index-law after administration. The results suggested that free radical scavengers or antioxidants should be useful for preventing cataracts at initial stage of the oxidation damage to lens, but they could aggravate cataracts at late stage of cataracts. This can explain the controversy about the curative effect of antioxidant to cataracts.

Animals↗
PubMed1999

[The clinic features of human immunodeficiency virus (HIV) on ear, nose, throat head and neck].

OBJECTIVE: To identify the clinic features of HIV infection on ENT-Head and neck area and to explore its treatment. METHOD: 68 HIV cases in zambia were analysed. RESULT: The ages of the patients are from 3 months to 46 year old. Among them 12 cases with Lump of neck, 9 with ulcer of oral-pharynx, 9 with parctid gland enlarged, 2 with submaxillary plleymon, 5 with nasal bleeding, 17 with purulent otitis Media, 4 with atrophic rhinitis. 18 cases in 58 HIV patients had tubericulosis, diarhea and anemia. 51 cases improved after treatment while 15 cases didn't improve and 2 died. CONCLUSION: It is very important to find and treat HIV patients and to prevent transmission as early as possible.

Adolescent↗
PubMed1999

[Separation of levonorgestrel, progesterone and testosterone by micellar electrokinetic capillary chromatography].

Separation of levonorgestrel, progesterone and testosterone was achieved by using micellar electrokinetic capillary chromatography (MECC). A column of 53 cm (to the detector) x 50 microns i.d. uncoated fused-silica capillary (totally 68 cm in length) and an ultra-violet detector with fixed wavelength at 254 nm were used throughout all the experiments. MECC analysis was optimized by evaluating three different micelle-forming agents, the concentration of SDS and several of organic additives in a 10 mmol/L borate running buffer (pH 9.2). Complete separations were obtained with either 10%-20% acetonitrile or 20 mmol/L 2,6-dimethyl-beta-cyclodextrin (DM-beta-CD) as the modifier in buffer. When the acetonitrile volume fraction was in the range of 0-15%, the migration times of the three steroids increased with the acetonitrile volume fraction, but in the range of 15%-20% acetonitrile concentrations, the situation was opposite. This behavior of the steroids was attributed to the interaction of two opposite effects, an increased mobility due to decreased partition coefficient and a decreased electroosmotic flow (EOF). Both beta-cyclodextrin (beta-CD) and gamma-cyclodextrin (gamma-CD) were found to be inadequate for a satisfactory separation.

Chromatography, Micellar Electrokinetic Capillary↗
PubMed1999

[Treatment of chronic prostatitis with computerized herbal drug penetrator].

A computerized herbal drug penetrator for chronic prostatitis was designed and developed on the basis of a combination of the authors' clinical practice with modern Traditional Chinese Medicinal theories. The device has integrated many hi-techs of current engineering science. It works by applying special herbal medicine, electro-magnetic effects, thermal moxibustion, perfusion and pulsated massage with water-capsule. The result of using this technique in the treatment of 100 cases has demonstrated its satisfying effectiveness.

Acupuncture Therapy↗
PubMed1999

[Purification and characterization of antifungal peptide LP-1].

An antifungal peptide LP-1 from Bacillus subtilis TG26 strain was purified by acid precipitation, acetone precipitation and Hi-pore reversed phase column chromatography. The molecular weight of LP-1 is 1057.3 D as determined by MALDI-TOF mass spectrometry, and its pI is 4.75 by PAG-IEF. It was also found to be thermostable. Its antifungal spectrum showed that LP-1 has strong inhibitory activity against many plant pathogenic fungi, such as Pythium aphanidermatum, Gibberella zeae, Alternaria longipe, Fusarium oxysporum f. lycopersici, etc.. The abnormal hyphal growth of Trichoderma viride caused by LP-1 such as swollen tips, twisted, short growth and cytoplasm condensation was also observed. Both ninhydrin reaction and peptide sequencing suggested that LP-1 is a cyclic peptide.

Anti-Bacterial Agents↗
PubMed1999

[Diagnostic value of B-scan in exudative age-related macular degeneration].

PURPOSE: To explore the image features of exudative age-related macular degeneration (AMD) with B-scan. METHODS: Using NIDEK US-3300 model B-scan to observe 31 patients (54 eyes) with AMD. RESULTS: The membranous arc echo was found at the posterior polar and there was a shuttle absence of echo between the echo band and the wall of eyeball in the period of retinal pigment epithelium detachment. During the exudation and hemorrhage absorbed not comletely, mixed echo was seen. A small parenchyma body with protrusion was seen with stronger echo in the late phase when the exudation and hemorrhage were replaced by the scar tissues, it was like a convex lens or a triangle and the top pointed to the globe behind, but it was flat towards the vitreous. CONCLUSION: The B-scan examination is valuable in diagnosis, treatment and follow-up for exudative AMD.

Aged↗
PubMed1998

Induction of mitogen-activated protein kinase phosphatase-1 by arachidonic acid in vascular smooth muscle cells.

Arachidonic acid (AA) and its metabolites play important roles in a variety of biological processes, such as signal transduction, contraction, chemotaxis, and cell proliferation and differentiation. It was demonstrated recently that AA can activate mitogen-activated protein kinases (MAPKs), which are crucial for transducing signals initiating cell growth and apoptosis. Here we studied the effect of AA on the induction of MAPK phosphatase-1 (MKP-1) in vascular smooth muscle cells (VSMCs) and found that AA stimulated induction of MKP-1 mRNA and proteins in VSMCs in a time- and dose-dependent manner. Specific inhibitors of cyclooxygenase-, lipoxygenase-, and cytochrome P450-dependent metabolism did not affect AA-induced MKP-1 expression, indicating that eicosanoid biosynthesis was not involved in this process. The glutathione precursor N-acetylcysteine, an antioxidant, abolished AA-stimulated MKP-1 gene expression, whereas inhibition of protein kinase C by calphostin C had no influence on MKP-1 induction. VSMC pretreatment with genistein, a tyrosine kinase inhibitor, completely blocked AA-stimulated MKP-1 induction. MAPK kinase inhibitor PD 98059 did abolish AA-stimulated activation of extracellular signal-regulated kinases but not MKP-1 induction. Furthermore, agonists that increase AA release stimulated MKP-1 induction and activation of MAPKs, including extracellular signal-regulated kinases and c-Jun NH2-terminal protein kinases or stress-activated protein kinases. Taken together, our findings demonstrate that AA induced MKP-1 expression in VSMCs via activation of tyrosine kinases involving AA-induced free radical generation, suggesting an important role for MKP-1 in the regulation of AA-initiated signal transduction in VSMCs.

Animals↗
PubMed1998

[Effect of selenium on children suffered from Mycoplasma pneumonia].

In order to evaluate the therapeutic effects of Selenium (Se) on Mycoplasma pneumonia, a clinical study was conducted in hospitalized patients using a double blind controlled method. The patients were randomly divided into two groups, the control patients received the routine treatment, and the supplemented group was given 1 mg sodium selenite one time only in addition to the routine treatment. The present study showed that concomitant of Se and routine treatment was superior to routine treatment alone in terms of improvement of clinical signs, time needed for relieving symptoms and signs (P < 0.05). The levels of Se and glutathione peroxidase in plasma and white blood cell were increased in Se supplemented group (P < 0.05). Higher proportion of patients in the treated group showed normalization of T cell subset parameters as compared with the control group. It can be concluded that supplementation of Se would be conducive to the improvement of the nutritional status and the increase of the ability of resisting-infection.

Adolescent↗
PubMed1998

Supercritical fluid extraction and off-line clean-up for the analysis of organochlorine pesticide residues in garlic.

An approach using supercritical fluid extraction (SFE) followed by clean-up with a AgNO3-loaded Florisil column was utilized for the analysis of four organochlorine pesticides (OCPs) in garlic. The organic sulfur extracted by SFE from garlic was removed by AgNO3 allowing OCPs to be determined by GC-electron-capture detection without interferences. All OCPs recoveries ranged from 85.0% to 110.0% and relative standard deviations were in the range of 3.9-7.2% for spiked samples. The described method may be used to analyze OCPs in garlic on a routine basis.

Chromatography, Gas↗
PubMed1998

Hypoxia induces high-mobility-group protein I(Y) and transcription of the cyclooxygenase-2 gene in human vascular endothelium.

Cyclooxygenases catalyze a rate-limiting step in the synthesis of vascular endothelial prostaglandins. Expression of the inducible cyclooxygenase-2 (COX-2) gene is increased by hypoxia in human vascular endothelial cells via the nuclear factor (NF)-kappaB p65 transcription factor, which is necessary but not sufficient to fully induce COX-2 transcription in response to hypoxia. After finding that cytoplasmic NF-kappaB p65 and IkappaBalpha (an inhibitory protein that binds NF-kappaB p65 precursors) levels are not changed by hypoxia, we hypothesized that other factors might play a role in regulating the COX-2 promoter, like the high-mobility-group (HMG) I(Y) family of proteins, which features multiple A.T hooks and is associated with NF-kappaB-mediated transactivation. Nuclear protein obtained from human umbilical vein endothelial cells (HUVECs) was supplemented with HMG I(Y) during electrophoretic mobility shift assays using an NF-kappaB-3' element probe. These data suggested that HMG I(Y) proteins interact with NF-kappaB p65 to induce COX-2 promoter activity. We also found that TATA-box DNA demonstrated increased electrophoretic shifting indicative of DNA binding after incubation with either hypoxic HUVEC nuclear protein or normoxic nuclear protein supplemented with HMG I(Y). Transfection of HUVECs with an expression vector containing the COX-2 promoter ligated to HMG I(Y) cDNA demonstrated positive feedback on COX-2 promoter activity in hypoxia. We confirmed that COX-2 is transcriptionally regulated by hypoxia using a nuclear runoff assay. Hypoxia increased steady-state cellular levels of HMG I(Y) mRNA as an early event, corresponding with increases in HMG I(Y) protein. Overexpression of HMG I(Y) was associated in a dose-response relationship with increasing prevalence of the COX-2 protein in hypoxic HUVECs. Furthermore, sense (and antisense) HMG I(Y) overexpression caused stimulation (or inhibition) of COX-2 promoter activity as measured by luciferase reporter gene expression. The physiological significance of these findings was demonstrated by cyclooxygenase-dependent release of prostaglandin E2 by HUVECs in hypoxia. We concluded that hypoxia increases expression of HMG I(Y) proteins while facilitating transactivation of the COX-2 promoter. The HMG I(Y) family of proteins may therefore function as part of a hypoxia-induced enhanceosome that helps to promote transcription of COX-2.

Cell Hypoxia↗
PubMed1998

Crystal structures of Flavobacterium glycosylasparaginase. An N-terminal nucleophile hydrolase activated by intramolecular proteolysis.

Glycosylasparaginase (GA) is a member of a novel family of N-terminal nucleophile hydrolases that catalytically use an N-terminal residue as both a polarizing base and a nucleophile. These enzymes are activated from a single chain precursor by intramolecular autoproteolysis to yield the N-terminal nucleophile. A deficiency of GA results in the human genetic disorder known as aspartylglycosaminuria. In this study, we report the crystal structure of recombinant GA from Flavobacterium meningosepticum. Similar to the human structure, the bacterial GA forms an alphabetabetaalpha sandwich. However, some significant differences are observed between the Flavobacterium and human structures. The active site of Flavobacterium glycosylasparaginase is in an open conformation when compared with the human structure. We also describe the structure of a mutant wherein the N-terminal nucleophile Thr152 is substituted by a cysteine. In the bacterial GA crystals, we observe a heterotetrameric structure similar to that found in the human structure, as well as that observed in solution for eukaryotic glycosylasparaginases. The results confirm the suitability of the bacterial enzyme as a model to study the consequences of mutations in aspartylglycosaminuria patients. They also suggest that further studies are necessary to understand the detail mechanism of this enzyme. The presence of the heterotetrameric structure in the crystals is significant because dimerization of precursors has been suggested in the human enzyme to be a prerequisite to trigger autoproteolysis.

Amino Acid Sequence↗
PubMed1998

Enhanced expression of heat shock protein 70 (hsp70) and heat shock factor 1 (HSF1) activation in rheumatoid arthritis synovial tissue. Differential regulation of hsp70 expression and hsf1 activation in synovial fibroblasts by proinflammatory cytokines, shear stress, and antiinflammatory drugs.

Heat shock proteins (hsp) have been repeatedly implicated to participate in the pathogenesis of rheumatoid arthritis (RA). Herein, we investigated the regulation of synovial hsp70 expression by analyzing the DNA-binding activity of heat shock transcription factor 1 (HSF1) as well as inducible hsp70 expression. Experiments were performed both on synovial tissue and on synovial fibroblast-like cells (SFC). Gel mobility shift analysis revealed increased HSF1 activation, and Western blotting and immunohistochemistry revealed increased hsp70 expression in RA synovial tissue, but not in synovial tissue derived from patients with osteoarthritis. Proinflammatory cytokines (TNF-alpha, IL-1alpha, IL-6), but not IFN-gamma or TGF-beta, induced activation of HSF1-DNA binding and hsp70 expression in cultivated SFC. Activation of HSF1 in SFC was accompanied by hyperphosphorylation and nuclear translocation of HSF1. Furthermore, shear stress also induced a complete heat shock response in cultivated synovial cells. In contrast, nonsteroidal antiinflammatory drugs triggered only an incomplete heat shock response, with HSF1 activation but not hsp70 induction, whereas steroids and immunosuppressive drugs did not affect the heat shock response at all. In summary, these data suggest that induction of hsp70 expression in rheumatoid synovial tissue is based on transcriptional activation of HSF1 due to the presence of proinflammatory cytokines (and possibly also shear stress).

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1998

Evidence for the use of fire at zhoukoudian, china

Zhoukoudian is widely regarded as having the oldest reliable evidence for the controlled use of fire by humans. A reexamination of the evidence in Layer 10, the earliest archaeological horizon in the site, shows that burned and unburned bones are present in the same layer with stone tools. However, no ash or charcoal remnants could be detected. Hence, although indirect evidence for burning is present, there is no direct evidence for in situ burning.

Journal Article↗
PubMed1998

Recombinant dengue virus type 1 NS3 protein exhibits specific viral RNA binding and NTPase activity regulated by the NS5 protein.

The full-length dengue virus NS3 protein has been successfully expressed as a 94-kDa GST fusion protein in Escherichia coli. Treatment of the purified fusion protein with thrombin released a 68-kDa protein which is the expected molecular mass for the DEN1 NS3 protein. The identity of this protein was confirmed by Western blotting using dengue virus antisera. Two related activities of the recombinant NS3 protein were characterized, which were the binding of the protein to the 3'-noncoding region of the dengue virus RNA genome and NTPase activity. We demonstrated using a band shift assay that the DEN1 NS3 protein could form a complex with the stem-loop structure in the 3'-noncoding region (3'-NCR), although sites outside the stem-loop may also participate in binding. Using various unlabeled homopolymeric and heteropolymeric RNAs as competitors for binding, it was further shown that the DEN1 NS3 protein exhibits preferential binding to a 94-nt RNA transcript from the 3'-NCR of the dengue virus. The NTPase activity of the recombinant DEN1 NS3 protein was characterized using a thin-layer chromatography assay. We found that the DEN1 NS3 protein possesses some aspects of NTPase activity, which are distinct from those found in other flaviviruses. Although the NS3 protein was able to utilize all four ribonucleoside triphosphates as its substrates, the NS3 protein showed a distinct preference for purine triphosphates (i.e., ATP and GTP). The addition of poly(U) did not stimulate NTPase activity in DEN1 NS3 protein, which contrasts with the reports for other flaviviral NS3 proteins. However, NTPase activity was specifically stimulated by the viral NS5 protein, which was manifested by a more than twofold increase in the rate of ATP hydrolysis and a 25% increase in the yield of ADP at the end of a 120-min reaction. These data suggest that the NTPase activity of the NS3 protein may be regulated by the viral NS5 protein during virus replication.

Adenosine Triphosphatases↗