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Biomedical subjects

Y Qin

Publications and source records attributed to Y Qin.

At least 55 records · Page 3Linked to original sources
PubMed2000

beta-oxidation - strategies for the metabolism of a wide variety of acyl-CoA esters.

Living organisms are exposed to a number of different fatty acids and their various derivatives arising either via endogenous synthesis or from exogenous sources. These hydrophobic compounds can play specific metabolic, structural or endocrinic functions in the organisms before their elimination, which can be metabolism to CO(2) or to more polar lipid metabolites allowing their excretion. Quantitatively, one of the major pathways metabolizing fatty acids is beta-oxidation, which consists of a set of four reactions operating at the carbons 2 or 3 of acyl-CoA esters and shortening of the acyl-chain. To allow the beta-oxidation of acyl groups with various steric variants to proceed, different strategies have been developed. These strategies include evolution of beta-oxidation enzymes as paralogues showing specificity with respect to either chain-length or modified acyl-chain, metabolic compartmentalization in eukaryotic cells, controlling of substrate transport across membranes, development of auxiliary enzyme systems, acquisition of enzymes with adaptive active sites and recruiting and optimizing enzymes from non-homologous sources allowing them to catalyze a parallel set of reactions with different substrate specificities.

3-Hydroxyacyl CoA Dehydrogenases↗
PubMed2000

The antiactivator TraM interferes with the autoinducer-dependent binding of TraR to DNA by interacting with the C-terminal region of the quorum-sensing activator.

Conjugal transfer of Agrobacterium tumefaciens Ti plasmids is regulated by quorum sensing via the transcriptional activator TraR and the acyl-homoserine lactone Agrobacterium autoinducer (AAI). Unique to this system, the activity of TraR is negatively modulated by an antiactivator called TraM. Analyses from yeast two-hybrid studies suggest that TraM directly interacts with the activator, but the conditions under which these components interact and the region of TraR responsible for this interaction are not known. Induction of traM in a strain in which TraR was activating transcription of a reporter system led to rapid cessation of gene expression. As assessed by a genetic assay that measures AAI-dependent DNA binding, TraM inhibited TraR function before and after the transcription factor had bound to its DNA recognition site. Consistent with this observation, in gel retardation assays, purified TraM abolished the DNA binding activity of TraR in a concentration-dependent manner. Such inhibition occurred independent of the order of addition of the reactants. As assessed by far Western analyses TraM interacts with TraR by directly binding the activator. TraM in its native form interacted with native TraR and also with heat-treated TraR but only when SDS was included with the denatured protein. TraM interacted with TraR on blots prepared with total lysates of cells grown in the presence and absence of AAI. Far Western analysis of N- and C-terminal deletion mutants localized a domain of TraR contributing to TraM binding to the C-terminal portion of the activator protein. Random mutagenesis by hydroxylamine treatment and error-prone polymerase chain reaction identified several residues in this region of TraR important for interacting with TraM as well as for transcriptional activation or/and DNA binding. We conclude that TraM inhibits TraR by binding to the activator at a domain within or close to the helix-turn-helix motif located at the C terminus of the protein.

Agrobacterium tumefaciens↗
PubMed2000

Study of the adsorption behavior of heavy metal ions on nanometer-size titanium dioxide with ICP-AES.

A new method using nanoparticle TiO2 as solid-phase extractant coupled with ICP-AES was proposed for simultaneous determination of trace elements. The adsorption behavior of nanometer TiO2 towards Cu, Cr, Mn and Ni was investigated by ICP-AES, and the adsorption pH curves, adsorption isotherms and adsorption capacities were obtained. It was found that the adsorption rates of the metal ions studied were more than 90% in pH 8.0-9.0, and 2.0 mol L-1 HCl was sufficient for complete elution. Nanometer TiO2 possesses a significant capacity for the sorption of the metal ions studied which is higher than the capacity of silica, the commonly used extractant. The method has been applied to the analysis of some environmental samples with satisfactory results.

Journal Article↗
PubMed2000

A transgenic insertion upstream of sox9 is associated with dominant XX sex reversal in the mouse.

In most mammals, male development is triggered by the transient expression of the Y-chromosome gene, Sry, which initiates a cascade of gene interactions ultimately leading to the formation of a testis from the indifferent fetal gonad. Several genes, in particular Sox9, have a crucial role in this pathway. Despite this, the direct downstream targets of Sry and the nature of the pathway itself remain to be clearly established. We report here a new dominant insertional mutation, Odsex (Ods), in which XX mice carrying a 150-kb deletion (approximately 1 Mb upstream of Sox9) develop as sterile XX males lacking Sry. During embryogenesis, wild-type XX fetal gonads downregulate Sox9 expression, whereas XY and XX Ods/+ fetal gonads upregulate and maintain its expression. We propose that Ods has removed a long-range, gonad-specific regulatory element that mediates the repression of Sox9 expression in XX fetal gonads. This repression would normally be antagonized by Sry protein in XY embryos. Our data are consistent with Sox9 being a direct downstream target of Sry and provide genetic evidence to support a general repressor model of sex determination in mammals.

Animals↗
PubMed2000

Color ultrasonography: a useful technique in the identification of nuchal cord during labor.

OBJECTIVE: To compare the accuracy of intrapartum ultrasound with and without color Doppler for identification of nuchal cord displacement during labor. METHODS: 180 normal pregnant women, admitted in labor, or for induction to labor, were examined independently by two researchers, using either conventional real-time gray-scale imaging or color Doppler imaging. A repeat examination was performed by the other researcher using the other ultrasound modality. Nuchal cord displacement was classified as either negative, definite or suspicious. Nuchal cord at birth was classified as either tight or loose. RESULTS: Sixty-two (34%) cases examined using the two ultrasound imaging modalities presented with nuchal cord at delivery. The sensitivity of color Doppler was 96.8%. The accuracy of color Doppler in detecting nuchal cord during labor was significantly better (P < 0.05) than gray-scale imaging alone. The results of a restricted sequential t-test analysis of 53 un-tied pairs showed an overall preference in favor of color Doppler assessment: statistical significance (P < 0.01) was reached after 41 un-tied pairs. CONCLUSIONS: The tight and loose nuchal cord could not be distinguished by ultrasound. Color Doppler imaging can provide useful additional information to gray-scale imaging in the detection of nuchal cord displacement during labor.

Female↗
PubMed2000

Determinants of umbilical cord arterial 8-iso-prostaglandin F2alpha concentrations.

OBJECTIVE: To determine the concentration of 8-isoPGF(2alpha) in cord blood as a measure of oxidative stress during labour, and to compare them with other established parameters of in vivo lipid peroxidation and with the acid-base status of the newborn. METHOD: Umbilical cord arterial and venous blood samples were collected from 81 singleton term deliveries for determination of 8-isoPGF(2alpha), malondialdehyde and organic hydroperoxides. In addition, metabolites derived from the oxidative metabolism of purines during hypoxia-reoxygenation and routine cord blood of oxygen saturation, pH, pO2, pCO2, HCO3 and base excess were measured. RESULTS: Arterial concentrations of 8-isoPGF(2alpha) were significantly higher in cases with fetal distress, tight nuchal cord (P < 0.001), the umbilical coiling index, and male sex (P < 0.05) (R2 = 0.48). No correlation was found with any parameter of acid-base status. In arterial and venous blood the concentrations of organic hydroperoxides and hypoxanthine significantly correlated with the fetal nuchal cord (P < 0.001) (R2 = 0.26 and 0.16, respectively). CONCLUSION: Our findings indicate that 8-isoPGF2(alpha) in cord arterial blood is a suitable parameter to quantify a possible oxidative stress in the fetus during labour. Measurements of the F2-isoprostane concentrations in cord blood at labour provide a clinically useful method to assess the perinatal outcome.

Acid-Base Imbalance↗
PubMed2000

Peroxisome proliferator-activated receptor gamma target gene encoding a novel angiopoietin-related protein associated with adipose differentiation.

The nuclear receptor peroxisome proliferator-activated receptor gamma regulates adipose differentiation and systemic insulin signaling via ligand-dependent transcriptional activation of target genes. However, the identities of the biologically relevant target genes are largely unknown. Here we describe the isolation and characterization of a novel target gene induced by PPARgamma ligands, termed PGAR (for PPARgamma angiopoietin related), which encodes a novel member of the angiopoietin family of secreted proteins. The transcriptional induction of PGAR follows a rapid time course typical of immediate-early genes and occurs in the absence of protein synthesis. The expression of PGAR is predominantly localized to adipose tissues and placenta and is consistently elevated in genetic models of obesity. Hormone-dependent adipocyte differentiation coincides with a dramatic early induction of the PGAR transcript. Alterations in nutrition and leptin administration are found to modulate the PGAR expression in vivo. Taken together, these data suggest a possible role for PGAR in the regulation of systemic lipid metabolism or glucose homeostasis.

3T3 Cells↗
PubMed2000

NBI-5788, an altered MBP83-99 peptide, induces a T-helper 2-like immune response in multiple sclerosis patients.

We assessed the immune response induced in multiple sclerosis (MS) patients who had received NBI-5788, an altered peptide ligand (APL) designed from an immunodominant region (83-99) of the neuroantigen myelin basic protein (MBP) (5, 10, or 20 mg subcutaneously weekly for 4 weeks). The mean frequency of NBI-5788-responsive T cells (stimulation index > 3) in MS patients treated with the APL was 35.8 +/- 12.8% (n = 7) compared with a mean frequency of 6.2 +/- 1.3% (n = 7) for the untreated patients. The mean frequency of whole MBP-responsive T cells in MS patients treated with the APL was not significantly different from that of untreated patients (16.4 +/- 5.7% vs 18.0 +/- 6.3%, respectively). NBI-5788-reactive T-cell lines generated from NBI-5788-treated patients exhibited an increased frequency of cross-reactivity with MBP peptide 83-99 compared with NBI-5788-reactive lines from control MS patients. Cytokine secretion by APL-reactive T-cell lines from NBI-5788-treated MS patients was more frequently T-helper 2-like compared with T-cell lines from untreated MS patients. These results demonstrate that subcutaneous administration of a soluble APL based on the MBP peptide 83-99 in MS patients can induce an APL-reactive immune response in which T lymphocytes cross-reactive with the immunodominant neuroantigen MBP secrete anti-inflammatory cytokines. The significant heterogeneity in immune response between individuals indicates the need for clinical laboratory correlation during the course of therapeutic trials.

Adult↗
PubMed2000

[A brief history of tracheotomy].

Tracheotomy was a term introduced by the German surgeon Heister in 1718. Other similar terms used before included bronchotomy and tracheostomy proposed by Negus in 1938. Being an old emergent operation, this operation can be traced back to the 1st century B.C. It was not until the 1920s-30s that this operation became a popularly applied and gradually completed one rather than an emergent operation adopted when there were no other alternatives.

General Surgery↗
PubMed2000

[Relationship of NO3(-)-N, NO2(-)-N accumulation in some crop seeds with N fertilizers application].

From 1996 to 1997, the effect of applying organic and chemical fertilizers on NO3- and NO2- accumulation in crop seeds was studied in four green food bases of kidney beans (Yunan Province), red small beans (Hebei Province), soybeans (Heilongjiang Province), and peanuts (Shandong Province). For kidney beans and red small beans, the highest grey correlation was existed between available N in soil and NO2- in seeds, no matter whether organic fertilizer or urea was applied. In organic fertilizer trials, the highest grey correlation appeared in soil pool (between total N and available N) or seed pool (between NO3- and NO2-), while in chemical N fertilizer trials, it existed between total N in soil and NO3- in seeds. For kidney beans and red small beans, the dynamics of NO3-/NO2- in seeds was different with the kind of fertilizers applied. Extremely significant negative linear correlation and positive linear regression were existed between the content of NO3- and NO2- in all four crop seeds.

Fabaceae↗
PubMed2000

[Effect of oxidatively modified high density lipoprotein on transcriptional expression of proto c-fos and PDGF receptor genes in cultured human arterial smooth muscle cell].

The proliferation of arterial smooth muscle cell (SMC) plays an important role in the process of atherosclero-genesis. Using the establishment of primary culture and sub-culture method for human arterial SMC, we observed the effects of native HDL (N-HDL) and oxidized HDL of proto c-fos and PDGF receptor genes transcriptional expression in cultured SMC. The results showed that N-HDL had no effect on the expression of proto c-fos and PDGF receptor genes in the cultured human SMC, that OX-HDL had no effect on the expression of PDGF receptor gene in the cultured human SMC, and that OX-HDL promoted the expression of protoc-fos gene significantly (P < 0.01). These results suggest that the OX-HDL's atherogenic role is closely related to its stimulating effect on proto c-fos gene expression of SMC.

Aorta↗
PubMed2000

[Research of toxin and plasmids of Saccharomyces cerevisiae].

Killer toxin from Saccharomyces cerevisiae SK was isolated by ultrafiltration of culture supernatants and purified by poly(ethylene glycol). The toxin migrates as one single protein band on SDS-PAGE and its molecular weight is 15 kD. The SK toxin has the greatest lethal effect on the sensitive yeast strain in the lat-lag phase. Extraction and purification of killer heretity factor(dsRNA) from SK found that M-dsRNA plasmid and L-dsRNA plasmid have different molecular lengths being 1.7 kb and 4.0 kb.

Killer Factors, Yeast↗
PubMed2000

[Supracricoid subtotal laryngectomy for the treatment of advanced laryngeal cancers].

OBJECTIVE: This procedure was designed to eradicate the advanced laryngeal carcinomas while preserving the laryngeal physiologic function. The indications and contraindications for the operation were also discussed and evaluated in this paper. METHODS: Twenty-one patients with advanced laryngeal cancers underwent this procedure during the period from 1988 through 1996 in our department. All of the patients were not amenable to conventional partial horizontal and vertical laryngectomies. In those patients, there were 9 supraglottic cancers, 10 glottic cancers and 2 transglottic cancers. Among them, 16 cases had stage T2 lesions and 5 cases had stage T3 lesions. In this procedure, the hyoid and thyroid cartilages were excised in toto, along with both true and false vocal cords, paraglottic space as well as the partial or total epiglottis and the whole preepiglottic space. The cricoid cartilage and at least one arytenoid cartilage were spared. The new larynx was reconstructed by suturing the cricoid and/or epiglottis to the base of the tongue. RESULTS: Of 21 patients, 95% were able to eat normally without aspiration, 90% were decannulated with near normal speech function. In two patients, the tracheotomy tube was reserved, one developed a stenosis, and another had recurrent aspiration pneumonia. No patients experienced local recurrence. Nineteen patients were followed up for at least 3 years, 13 patients achieved 5 years tumor-free survival. CONCLUSION: The term supracricoid subtotal laryngectomy best describes the surgical approach and the reconstruction model of the new larynx. As a useful alternative to total laryngectomy in selected advanced laryngeal cancers, this procedure may greatly improve the quality of life and prolong the life without recurrence.

Adult↗
PubMed2000

[IR spectra and structures of two trinuclear molybdenum cluster compounds coordinated by binary carboxylates].

Two trinuclear molybdenum cluster compounds coordinated by binary carboxylates compounds Mo3S4 (DTP)3(phthalate) (Py)(A) and Mo3S4 (DTP)3(malonate)(Py)(B) have been synthesized. IR absorption peaks of Mo3S4 core and the ligands are assigned with reference to those of Mo3S4(DTP)4(Py)(C). The assignment of stretching vibrations of carboxylate (COO-) for both (A) and (B) reveals much information corresponding to their molecular structures.

English Abstract↗
PubMed2000

[Study on simultaneous determination of multiplex trace elements in Chinese herbal medicine loulu by ICP-AES].

A method for the simultaneous determination of multiplex trace elements in Chinese herbal medicine Loulu by inductively coupled plasma atomic emission spectrometry(ICP-AES) has been presented. The operating condictions and the suitable internal standard elements were selected. The detection limits of the method are 0.005-1.24 micrograms.mL-1 for Fe, Mn, Cu, Ti, Cr, Ba, Sr, Zn, Al with relative standard deviations (RSD) of 1.20%-3.90% (n = 7). The recoveries of most elements are in the range of 90.1%-104.2%. The method proposed has been applied to the analysis of real samples and biological standard samples (GBW 08501) peach leaves. The determined values of trace elements in the biological standard sample were in good agreement with the certified values.

Asteraceae↗