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Biomedical subjects

X Gu

Publications and source records attributed to X Gu.

At least 73 records · Page 4Linked to original sources
PubMed2001

[Epidemiologic survey on mental health of maxillofacial traumatic inpatients].

OBJECTIVE: To Analyze the mental health level of maxillofacial traumatic inpatients. METHODS: The mental test was carried out in 126 maxillofacial traumatic inpatients of Department of Oral and Maxillofacial Surgery of the Fourth Military Medical University from 10/1998 to 09/1999 with the SCL-90 (symptom check list-90). RESULTS: The total mark of SCL-90 was 153.76 +/- 62.44. The number of symptomatic items was 31.52 +/- 24.55, which was higher than that of domestic norm (P < 0.01). The inpatient constitutes at different level of SCL-90 total mark showed normal distribution. The every factor mark of SCL-90 was also higher than that of domestic norm (P < 0.01). The former four factors were melancholy, anxiety, horror and psychosis. The SCL-90 factors mark had an increased trend along with injury severity score (RISS). The age and sex had not notable influence on the mental health level (P > 0.05), but the educational level had notable influence on the mental hralth level (P < 0.05). CONCLUSIONS: The mental health level of maxillofacial traumatic inpatients is lower than normal people and has a decreasing trend along with the RISS. The inpatient that has lower educational level also has lower mental health level. The mental handicap is caused by traumatic event and nosocomial stress.

Adolescent↗
PubMed2001

Expression of oncoproteins c-fos and c-jun in hypertrophic scars and chronic dermal ulcers and their regulation of basic fibroblast growth factor.

OBJECTIVE: To explore the characteristics of oncoprotein expression of c-fos and c-jun in hypertrophic scars and chronic dermal ulcers and their regulation of basic fibroblast growth factor (bFGF). METHODS: Tissues of hypertrophic scars (n = 8), chronic dermal ulcers (n = 8) and normal skin (n = 5) were taken from 21 patients with burns and chronic dermal ulcers in operation. The ABC immunohistochemical method was used to characterize the gene product expression of c-fos, c-jun and bFGF in the above tissues. RESULTS: In normal skin, both c-fos and c-jun protein expression and bFGF protein expression were observed. The signals of both oncoproteins were localized mainly in subcutaneous fibroblasts, but, positive expression of the bFGF protein was mainly in keratinocytes. In hypertrophic scars, positive expression of both oncoproteins could be found mainly in fibroblasts, but bFGF was mainly in fibroblasts and endothelial cells. In chronic dermal ulcers, endothelial cells, some of inflammatory cells and fibroblasts were positive for both of oncoproteins, but the expression of bFGF was only seen in fibroblasts and endothelial cells. CONCLUSIONS: The results indicate that the interaction between both oncoproteins and bFGF exists, and the regulating action between protooncogenes and bFGF is a major course in wound healing. The different expressions of c-fos and c-jun gene products play an important role in regulate bFGF action, thus affecting wound healing.

Chronic Disease↗
PubMed2001

Expression characteristics of c-fos, c-myc and bFGF in early burn tissue.

OBJECTIVE: To investigate the sequence and characteristics of expression of proto-oncogenes, c-fos, c-myc and endogenous basic fibroblast growth factor (bFGF), in burn tissue from rats. METHODS: A partial thickness burn of 30% TBSA was created on the backs of Wistar rats. Immunohistochemistry was used to detect the expression of these proteins in normal and burned skin at 3 hours, 6 hours, 1 day, 3 days, 7 days and 14 days postburn. RESULTS: Expression of c-fos, c-myc and bFGF was induced by the burn, but these three proteins showed different expression levels in sequence and distribution. Expression of c-fos increased and peaked at 3 hours postburn. Stain positive granules were distributed mainly in the cytoplasm of basal cells and the nuclei of fibroblasts. The expression of bFGF protein increased at 6 hours and peaked at 1 day postburn; it was distributed in the cytoplasm of fibroblasts. c-myc protein peaked at 3 days postburn and was also distributed in the cytoplasm of fibroblasts. CONCLUSIONS: Thermal injury can induce c-fos, c-myc and bFGF expression and show phasic control and regional distribution. The phasic expression of these three proteins indicates that there maybe a regulatory relationship between proto-oncogenes and growth factors in early burn. This may play an important role in late tissue repair.

Animals↗
PubMed2001

[Mobilization of autologous peripheral blood stem cells by combined chemotherapy and rhG-CSF].

OBJECTIVE: To study the effect of cyclophosphamide (CTX) combination chemotherapy and recombinant human granulocyte colony-stimulating factor (rhG-CSF) on autologous peripheral blood stem cells (APBSC) mobilization. METHODS: CTX(2.5 +/- 1.0) g/m2 on day 1, VP-16,600-800 mg and/or Ara-C 1.0-2.0 g/m2 on day 2 were injected i.v. rhG-CSF 300 micrograms/d was injected s.c. when the white blood cell (WBC) count reached nadir until one day before APBSC harvest. When the WBC count was over 3.0 x 10(9)/L, peripheral blood mononuclear cell (MNC) collection was performed once per day until the number of MNC collected was > 4 x 10(8)/kg. CFU-GM colony formation and CD34+ cell enumeration were performed. RESULTS: Twenty cases were studied. The lowest level of WBC was (1.2 +/- 0.8) x 10(9)/L on day 8.5 +/- 1.5 following chemotherapy. rhG-CSF was given from day 9.0 +/- 2.0 and continued for 6.0 +/- 1.0 days. APBSC harvest began on day 12.0 +/- 2.0 and continued for 4.0 +/- 1.0 days. A total of (6.14 +/- 2.34) x 10(8)/kg MNC and (23.25 +/- 30.56) x 10(6)/kg CD34+ cells was procured. Peak level of CD34+ cells was observed 14.6 +/- 1.8 days after chemotherapy and 4.9 +/- 1.6 days after rhG-CSF administration. CFU-GM was (21.68 +/- 15.39) x 10(4)/kg when rhG-CSF was given for 4.9 +/- 1.6 days. No severe toxic reaction was observed. Hematopoietic reconstitution was very well in all patients received APBSC transplantation. CONCLUSION: CTX combination chemotherapy followed by rhG-CSF was safe and feasible for APBSC mobilization.

Adolescent↗
PubMed2001

[Analysis of the relation between the operation time and functional recovery for the injured facial motor nerve].

OBJECTIVE: To analyse the relation between the operation time and functional recovery of the facial motor nerve. METHODS: 133 cases of facial motor nerve injury between 1983 and 1998 were involved in this survey. Most of them (130 cases) suffered from traumatic facial palsy. 73 cases were followed up for evaluating their functional recovery of mimic muscles according to the suggestion by the International Muscle Transplant Registry (1991). RESULTS: More than 80% cases of facial nerve injury were sharp cut. There were 28 cases undergone immediate or early repair of the facial nerve, 90 cases secondary repair, 15 cases neuromuscular transfer. The functional recovery was achieved in 24/28 cases in which the broken nerves were immediately or early repaired. CONCLUSIONS: The time to repair the injured motor nerve should be as early as possible, even for the facial palsy caused by tumor or tumor resection. There is still an urgent need to improve the method for objectively evaluating the functional recovery of the facial nerve.

Adolescent↗
PubMed2001

Effects of recombinant human basic fibroblast growth factor on cell proliferation during mandibular fracture healing in rabbits.

OBJECTIVE: To investigate the effects of recombinant human basic fibroblast growth factor (rhbFGF) on the cell proliferation during mandibular fracture healing in rabbits. METHODS: The complex of rhbFGF and bovine type I collagen was implanted into the mandibular fracture site under periosteum of the animal. The whole mandible was harvested at 7, 14, 28, 56 and 84 days respectively after operation. The expression of proliferating cell nuclear antigen (PCNA) in callus was examined with immunohistochemical staining. RESULTS: PCNA-positive cells in callus in the rhbFGF-treated group on days 7 and 14 were more than that in the control group (P<0.01). CONCLUSIONS: It indicates that rhbFGF can stimulate cell proliferation during mandibular fracture healing in rabbits.

Animals↗
PubMed2001

[Construction of rice dwarf virus genome database].

Secondary database construction is an important subject in the field of bioinformatics. As the full genomic sequences of some organisms are being completed and followed by structural and functional studies, construction of secondary database becomes essential on the agenda. The rice dwarf virus (RDV) is a pathogen infecting rice in China, Japan and the Southeastern Asia region and leading to considerable economic loss. Based on the data generated from recent genomic research and earlier biochemical studies scattered in various primary databases and scientific journals, we have constructed a compact, user-friendly and non-redundant job-oriented secondary database. This work will provide compiled useful information for plant molecular biologists as well as in achieving preliminary experiences in secondary database construction.

Databases, Factual↗
PubMed2001

[The characterization of pJW566 from L. Lactis subsp. cremoris W56].

The plasmid pJW566 was isolated from L. lactis subsp. cremoris W56, one strain for Danish chadder mixed starter cultures. The strain containing plasmid pJW566 showed resistance against three common phages species 936, c2 and P335 worldwide. It was found that pJW566 encoded for an restriction and modification system, and showed strong resistance to phage CHCP412 when it was introduced into the industrial strain L. lactis CHCC2281 in milk medium. The endonuclease activity analysis indicated that the endonuclease required Mg2+, ATP, and was stimulated by AdoMet.

Animals↗
PubMed2000

Tel-2 is a novel transcriptional repressor related to the Ets factor Tel/ETV-6.

We report here the isolation of Tel-2, a novel member of the Ets transcription factor family, with high homology to Tel/ETV-6. Tel-2 is the second mammalian member of the Tel Ets family subclass whose prototype Tel is involved in various chromosomal translocations in human cancers. Six differentially expressed alternative splice products of Tel-2 were characterized encoding different Tel-2 isoforms which either contain or lack the amino-terminal Pointed domain and also vary at the carboxyl terminus. In contrast to Tel, which is highly expressed in several different cell types and tissues, Tel-2 is only weakly expressed in a variety of tissues and cell types, including placenta, prostate, spleen, liver, and lung. Tel-2 binds to functionally relevant Ets-binding sites of several genes and only the Tel-2 isoform containing the Pointed domain and the DNA-binding domain acts as a strong repressor of transcription. The retinoic acid receptor alpha and bone morphogenetic protein-6B (BMP-6) genes are specifically repressed by Tel-2 indicating a function for Tel-2 as an inhibitor of differentiation. Due to the important involvement of Tel in human cancer and the location of Tel-2 within the MHC cluster region, Tel-2 might be involved in chromosomal translocations in human cancer as well.

Amino Acid Sequence↗
PubMed2000

Vascular endothelial growth factor activates STAT proteins in aortic endothelial cells.

Vascular endothelial growth factor (VEGF) intracellular signaling in endothelial cells is initiated by the activation of distinct tyrosine kinase receptors, VEGFR1 (Flt-1) and VEGFR2 (Flk-1/KDR). Because the tyrosine kinase-dependent transcription factors known as STAT (signal transducers and activators of transcription) proteins are important modulators of cell growth responses induced by other growth factor receptors, we have determined the effects VEGF of on STAT activation in BAEC (bovine aortic endothelial cells). Here, we show that VEGF induces tyrosine phosphorylation and nuclear translocation of STAT1 and STAT6. VEGF also stimulates STAT3 tyrosine phosphorylation, but nuclear translocation does not occur. We found that placenta growth factor, which selectively activates VEGFR1, has no effect on the STATs. However, upon VEGF stimulation, STAT1 associates with the VEGFR2 in a tyrosine kinase-dependent manner, indicating that VEGF-induced STAT1 activation is mediated primarily by VEGFR2. Thus, our study shows for the first time that VEGF activates the STAT pathway through VEGFR2. Because the growth-promoting activity of VEGF depends upon VEGFR2 activation, these findings suggest a role for the STATs in the regulation of gene expression associated with the angiogenic effects of VEGF.

Animals↗
PubMed2000

Scavenger receptor class B, type I-mediated [3H]cholesterol efflux to high and low density lipoproteins is dependent on lipoprotein binding to the receptor.

The murine scavenger receptor class B, type I (mSR-BI) is a receptor for high density lipoprotein (HDL), low density lipoprotein (LDL), and acetylated LDL (AcLDL). It mediates selective uptake of lipoprotein lipid and stimulates efflux of [(3)H]cholesterol to lipoproteins. SR-BI-mediated [(3)H]cholesterol efflux was proposed to be independent of ligand binding. In this study, using anti-mSR-BI antibody KKB-1 and two mSR-BI mutants with altered ligand binding properties, we demonstrated that SR-BI-mediated [(3)H]cholesterol efflux to lipoproteins was correlated with ligand binding and lipid uptake activities of the receptor. The KKB-1 antibody, which blocked lipoprotein binding without substantially altering the cholesterol oxidase-accessible cellular [(3)H]cholesterol, also blocked [(3)H]cholesterol efflux to HDL and LDL. One of the SR-BI mutants, which has a double substitution of arginines for glutamines at positions 402 and 418 (Q402R/Q418R), exhibited a high level of LDL binding and lipid uptake from LDL, but lost most of the corresponding HDL receptor activity. This mutant could mediate efficient [(3)H]cholesterol efflux to LDL, but not to HDL. Another mutant, M158R, with an arginine in place of methionine at position 158, exhibited reduced HDL and LDL receptor activities, but apparently normal AcLDL receptor activity. This mutant could mediate efficient [(3)H]cholesterol efflux to AcLDL, but not to HDL or LDL. These results suggest that SR-BI-stimulated [(3)H]cholesterol efflux to lipoproteins critically depends on ligand binding to this receptor and raise the possibility that the mechanisms of selective lipid uptake and [(3)H]cholesterol efflux may be intimately related.

Antibody Specificity↗
PubMed2000

Simultaneous determination of a novel thrombin inhibitor and its two metabolites in human plasma by liquid chromatography/tandem mass spectrometry.

I, 3-(2-phenethylamino)-6-methyl-1-(2-amino-6-methyl-5-methylene-c arboxamidomethylpyridinyl)-pyrazinone dihydrochloride monohydrate, is a potent, orally active thrombin inhibitor. The compound also has two metabolites which have been shown to have thrombin inhibitory activity: benzylic alcohol M3 metabolite (II) and hydroxymethylpyrazinone M7 metabolite (III). A liquid chromatography/tandem mass spectrometry (LC/MS/MS) method for the simultaneous determination of I and its two metabolites in human plasma has successfully been developed. The method consists of treating 0.5 ml plasma with 2 N NaOH and extracting I, II, III and internal standard (IV) with ethyl acetate:methyl-t-butyl ether (1:3, v/v). The analytes were then back-extracted into 2% formic acid. The analytes were chromatographed by high performance liquid chromatography (HPLC) and detected by MS/MS. Positive ionization was used on a heated nebulizer probe monitoring precursor --> product ion combinations in multiple reaction monitoring mode. The linear range is 0.5-1000 nM for I and III and 0.75-1000 nM for II. Recoveries were 88, 74, 78 and 102.1% for I, II and III and the internal standard, respectively in human plasma. Intraday variation using this method was < or = 7.9% for I, < or = 9.0%, for II and < or = 9.5% for III across the standard curve range. This method exhibits good linearity and reproducibility for the three analytes.

Chromatography, High Pressure Liquid↗
PubMed2000

Analysis of resveratrol in wine by capillary electrophoresis.

Capillary electrophoresis (CE) is a new analytical technique that has recently been reported as a method for analysis of resveratrol in wine. Several different separation approaches have been taken in these reports. In comparison with high-performance liquid chromatography (HPLC), CE methods have similar sensitivity and can discriminate between trans- and cis-isomers of resveratrol. CE methods also show promise for analysis of other flavonoid antioxidants (glycosides and aglycones) in wine.

Electrophoresis, Capillary↗
PubMed2000

Phosphorescent oxygen sensors utilizing sulfur-nitrogen-phosphorous polymer matrixes: synthesis, characterization, and evaluation of poly(thionylphosphazene)-b-poly(tetrahydrofuran) block copolymers

We examine the use of thionylphosphazene-based block copolymers as matrixes for oxygen sensor applications. Poly(aminothionylphosphazene)-b-poly(tetrahydrofuran) (PATPy-PTHFx) block copolymers were prepared via reaction of ring-opened poly(chlorothionylphosphazene) with THF and subsequently with excess n-butylamine (to form PBATPy-PTHFx) or methylamine (to form PMATPy-PTHFx). The block copolymers were characterized by NMR, gel permeation chromatography, and differential scanning calorimetry. Films of PBATPy-PTHFx block copolymers containing platinum octaethylporphyrin or [Ru(dpp)3]Cl2 (dpp = 4,7-diphenyl-1,10-phenanthroline) as the oxygen-sensitive chromophore were prepared, and time-scan experiments were carried out to determine the diffusion coefficients, Do2, and solubilities, So2, of oxygen therein. Despite microphase separation, the data fit well to a simple Fick's law description of oxygen diffusion and gave Do2 values smaller than that for the n-butylamino-substituted PBATP635. For films freshly annealed above the melting point of PTHFx, the Do2 values were 35-50% (dye-dependent) larger than after aging 3 days at room temperature. Films with [Ru(dpp)3]Cl2 as the dye were evaluated as media for phosphorescent pressure-sensing. The dye-containing polymer films exhibit linear Stern-Volmer-like plots, even at high dye concentrations, as well as good photostability, and significantly higher sensitivity to oxygen quenching than simple mixtures of the analogous homopolymers.

Journal Article↗
PubMed2000

Dissociation of the high density lipoprotein and low density lipoprotein binding activities of murine scavenger receptor class B type I (mSR-BI) using retrovirus library-based activity dissection.

The murine class B, type I scavenger receptor (mSR-BI) is a receptor for both high density lipoprotein (HDL) and low density lipoprotein (LDL) and mediates selective, rather than endocytic, uptake of lipoprotein lipid. We have developed a "retrovirus library-based activity dissection" method to generate mSR-BI mutants in which some, but not all, of the activities of this multifunctional protein have been disrupted. This method employs three techniques: 1) efficient in vitro cDNA mutagenesis (here error-prone PCR was used), 2) efficient retroviral delivery and high expression of single mutant cDNAs into individual cells, and 3) isolation of infected cells expressing the desired mutant phenotype using high sensitivity positive/negative screening by two-color fluorescence-activated cell sorting. A set of mutants, all having arginine substitutions at two common sites (positions 402 or 401 and position 418), were isolated and characterized. Mutation at either site alone did not generate as strong a mutant phenotype (loss of DiI uptake from DiI-HDL) as did the double mutations. "Activity-dissected" double mutants were as effective as wild-type mSR-BI in functioning as LDL receptors, mediating high affinity LDL binding and uptake of metabolically active cholesterol from LDL, but they lost most of their corresponding HDL receptor activity. Thus, these mutants provide support for the proposal that the interaction of SR-BI with HDL differs from that with LDL. Examination of the in vivo function of such mutants may provide insights into the differential roles of the LDL and HDL receptor activities of SR-BI in normal lipoprotein metabolism and in SR-BI's ability to protect against atherosclerosis.

Amino Acid Sequence↗
PubMed2000

A novel Pax-6 binding site in rodent B1 repetitive elements: coevolution between developmental regulation and repeated elements?

Pax-6 encodes a transcription factor that is important in the development of eye and CNS. Identification of Pax-6 target genes is crucial for understanding the gene regulatory network in these developmental processes. Using an in-vitro approach of cyclic amplification of the protein binding sequences (CAPBS), we isolated a PAX6 binding sequence from a human single-copy (sc) DNA library. Characterization of this PAX6 binding sequence revealed a 15bp region (hGCalpha1BLs5) that is sufficient for PAX6 specific binding. From a homology search in the GenBank, we found that an hGCalpha1BLs5-like Pax-6 binding site exists in 21 genes (16 from rodent), 15 of which were shown to be able to bind Pax-6 in vitro. Interestingly, some of these sites occur in B1 repetitive elements. Although hGCalpha1BLs5 is highly similar to a region in B1 repetitive elements, PAX6 does not bind to the consensus sequence in B1. However, a single-step mutation in some B1 elements can lead to a gain of function for PAX6 binding. This experimental evidence and phylogenetic analysis raise an interesting speculation for the coevolution between PAX6 regulation and repeat elements. Since a (Pax-6-binding) null B1 element can be re-activated by even a single-step mutation, it has the potential to recruit gene targets for Pax-6 if it is inserted into the regulatory region, and therefore may play a role for evolutionary modification of Pax-6 regulation.

Animals↗