Biomedical subjects

L Qi

Publications and source records attributed to L Qi.

At least 19 recordsLinked to original sources

PubMed2006

The effect of conjugated equine oestrogen on diabetes incidence: the Women's Health Initiative randomised trial.

AIMS/HYPOTHESIS: Recent clinical trials have found that the combination of conjugated equine oestrogen (CEO) and medroxyprogesterone has a protective effect on the incidence of type 2 diabetes. To determine the effect of CEO alone on the incidence of diabetes mellitus in postmenopausal women, we analysed the results of the Women's Health Initiative oestrogen-alone trial. METHODS: The Women's Health Initiative is a randomised, double-masked trial comparing the effect of daily 0.625 mg CEO with placebo during 7.1 years of follow-up of 10,739 postmenopausal women who were aged 50-79 years and had previously had a hysterectomy. Diabetes incidence was ascertained by self-report of treatment with insulin or oral hypoglycaemic medication. Fasting glucose, insulin and lipoproteins were measured in an 8.6% random sample of study participants, at baseline and at 1, 3 and 6 years. RESULTS: The cumulative incidence of treated diabetes was 8.3% in the oestrogen-alone group and 9.3% in the placebo group (hazard ratio 0.88, 95% CI 0.77-1.01, p=0.072). During the first year of follow-up, a significant fall in insulin resistance (homeostasis model assessment of insulin resistance) in actively treated women compared with the control subjects (Year 1 baseline between-group difference -0.53) was seen. However, there was no difference in insulin resistance at the 3- or 6-year follow-up. CONCLUSIONS/INTERPRETATION: Postmenopausal therapy with oestrogen alone may reduce the incidence of treated diabetes. The effect is smaller than that seen with oestrogen plus progestin. CEO should not, however, be used with the intention of preventing diabetes, as its well-described adverse effects preclude long-term use for primary prevention.

Aged↗

PubMed2005

Discrete serum protein signatures discriminate between human retrovirus-associated hematologic and neurologic disease.

The human T-cell leukemia virus type I (HTLV-I) is the causative agent for adult T-cell leukemia (ATL) and HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Approximately 5% of infected individuals will develop either disease and currently there are no diagnostic tools for early detection or accurate assessment of disease state. We have employed high-throughput expression profiling of serum proteins using mass spectrometry to identify protein expression patterns that can discern between disease states of HTLV-I-infected individuals. Our study group consisted of 42 ATL, 50 HAM/TSP, and 38 normal controls. Spectral peaks corresponding to peptide ions were generated from MS-TOF data. We applied Classification and Regression Tree analysis to build a decision algorithm, which achieved 77% correct classification rate across the three groups. A second cohort of 10 ATL, 10 HAM and 10 control samples was used to validate this result. Linear discriminate analysis was performed to verify and visualize class separation. Affinity and sizing chromatography coupled with tandem mass spectrometry was used to identify three peaks specifically overexpressed in ATL: an 11.7 kDa fragment of alpha trypsin inhibitor, and two contiguous fragments (19.9 and 11.9 kDa) of haproglobin-2. To the best of our knowledge, this is the first application of protein profiling to distinguish between two disease states resulting from a single infectious agent.

Adolescent↗

PubMed2004

Genetic variation at the hormone sensitive lipase: gender-specific association with plasma lipid and glucose concentrations.

Hormone-sensitive lipase (HSL) catalyzes the intracellular hydrolysis of triacylglycerols and cholesteryl esters, and it is involved in regulating body fat, steroidogenesis, and insulin secretion. Thus, genetic variability at the HSL locus (LIPE) may play a significant role on lipid metabolism and the risk of obesity and type 2 diabetes. Therefore, we have examined two LIPE single nucleotide polymorphism (SNP) [14672C>G in the promoter region and 17948C>T (rs1206034) on intron 2] in relation to plasma lipids, anthropometrical and glucose-related phenotypes in a population of mostly overweight and obese men (373) and women (361). In women, the 17948T allele was associated with decreased total cholesterol (TC, p = 0.001), LDL-cholesterol (LDLc, p < 0.001) and apoE concentrations (p = 0.041). Conversely, female carriers of the LIPE 14672G allele had significantly higher TC (p = 0.047), LDLc (p = 0.041), and apoE (p = 0.041) levels. Although we did not find significant associations in men, we observed that male carriers of the LIPE 14672G who did not drink alcohol showed higher glucose levels than non-carriers (p = 0.008), whereas there were no allele-related differences among drinkers (p = 0.019 for the interaction). These SNPs were not significantly associated with anthropometrical variables. In summary, variation at this locus showed gender-specific associations with lipids and glucose measures, and the latter was influenced by alcohol drinking.

Base Sequence↗

PubMed2004

Genetic variation at the perilipin (PLIN) locus is associated with obesity-related phenotypes in White women.

Perilipin coats intracellular lipid droplets and modulates adipocyte lipolysis. We have evaluated the association between several polymorphisms at the perilipin (PLIN) locus (PLIN1 : 6209T > C, PLIN4 : 11482G > A, PLIN5 : 13041A > G, and PLIN6 : 14995A > T) with obesity-related phenotypes in 1589 White subjects randomly selected from a general Spanish population. In women (n = 801), the less common alleles of PLIN1 and PLIN4, in strong linkage disequilibrium (D' : 0.96), were significantly associated with lower body mass index. Carriers of the allele 2 (6209C) at the PLIN1 locus weighed significantly less (-2.2 kg; p = 0.007) than women homozygotes for the wild-type genotype. The same was true for 11482A carriers at PLIN4 (p = 0.01). Moreover, the PLIN4 variant was associated with significantly lower waist-to-hip ratio, plasma glucose, and triacylglycerol concentrations. No significant associations with these obesity-related phenotypes were found in men. In agreement with these results, statistically significant gene-gender interactions were obtained when the risk of obesity was estimated (281 subjects were obese and 1308 non-obese). Only in women, PLIN1 and PLIN4 variant alleles (6209C and 11482A) were associated with a lower obesity risk [Odds ratio (OR) = 0.58, 95% confidence interval (CI): 0.38-0.93 and OR = 0.56, 95% CI: 0.36-0.89, respectively]. In summary, our data suggest that common alleles at the PLIN locus modulate body weight and metabolic variables in humans.

Adolescent↗

PubMed2003

Hearts and bones.

Cardiovascular disease (CVD) and osteoporosis (OP) are two common degenerative processes that contribute in great measure to the decline in performance and quality of life of the elderly population. Traditionally, these disorders have been considered as distinct and unrelated entities. However, over the last few years, there has been increasing evidence supporting an important link between CVD and OP. Several genetic association and linkage studies have shown the existence of common genetic determinants for cardiovascular and skeletal diseases. These genes code for several key players on the metabolism of nutrients, such as lipids, calcium and folate, as well as other factors (e.g. sex hormone receptors) that are known to be subject to dietary modulation, suggesting the links at the level of dietary response. Some dietary factors have shown similarities in influencing the risks of both conditions. However, some others act differently in relation with their effects on the development of cardiovascular disease and osteoporosis. We therefore suggest that, any dietary and behavioral recommendations targeting to the 'global health' of the ageing population would take a comprehensive consideration of their potentially diverse effects (beneficial or deleterious) on the risks of various ageing related disorders, and would be tailored to the individual genetic background.

Aged↗

PubMed2002

Porphyrins as early biomarkers for arsenic exposure in animals and humans.

We studied the effect of arsenic exposure on the haem biosynthetic pathway in the rat and humans. Significant increases in protoporphyrin IX, coproporphyrin III, coproporphyrin I were observed in the blood, liver and kidney, and in the urine of rats after a single dose of arsenic. The level of increase was dependent on the arsenic species present. Most of porphyrin concentrations in the tissues increased within 24 hr and urinary excretion elevated within 48 hr. In the human study, we collected urine samples from 113 people who live in Xing Ren of Guizhou Province, a coal-borne arsenicosis endemic area in southwest of PR China and from 30 people who live in Xing Yi (about 80 km southwest of Xing Ren) where arsenicosis is not prevalent. We analyzed the urinary porphyrins using HPLC. Results indicate that all urinary porphyrins were higher in the arsenic exposed group than those in the control group. Women, children and older age people spend much of their time indoors, they had greater increases of urinary arsenic and porphyrins. They were the higher risk groups among the study subjects. A positive correlation between the urinary arsenic levels and porphyrin concentrations demonstrated the effect of arsenic on haem biosynthesis. Significant alteration in the porphyrin excretion profiles of the younger age (<20 y) arsenic exposed group suggested that porphyrins could be used as early warning biomarkers for chronic exposure to arsenic.

Age Factors↗

PubMed2001

Formation of BaSO4 fibres with morphological complexity in aqueous polymer solutions.

BaSO4 fibres with morphological complexity were formed in aqueous solution with polyacrylate and partially monophosphonated poly(ethyleneoxide)-block-poly(methacrylic acid) additives by a simple precipitation reaction. For polyacrylate, formation of the fibrous deposits was strongly dependent on the level of supersaturation (S) and Ba2+:polymer molar ratio (R). At S = 60 to 80, and R = 3 to 14, highly anisotropic crystalline fibres consisting of bundles of BaSO4 nanofilaments were formed after several weeks, although the yield was low. The nanofilaments were also organized into cone-shaped aggregates at S = 80, and at lower R values these formed higher-order structures that consisted of multiple cone-on-cone assemblies with remarkable self-similarity. Increasing the supersaturation produced ovoid or cross-shaped dendritic particles for the range of molar ratios studied. In contrast, BaSO4 crystallisation in the presence of a partially phosphonated block copolymer gave a high yield of BaSO4 fibres up to 100 microm in length, and consisting of co-aligned bundles of 30 nm-diameter defect-free single-crystal nanofilaments with a uniform growth tip. A model for the defect-free growth of BaSO4 nanofilaments in aqueous polymer solutions based on amorphous precursor particles, vectorially directing forces and van der Waals attraction is proposed.

Journal Article↗

PubMed2001

H2-O inhibits presentation of bacterial superantigens, but not endogenous self antigens.

H2-O/HLA-DO are MHC class II accessory molecules that modulate exogenous Ag presentation. Most class II accessory molecules are expressed in all professional APC; however, H2-O is only expressed in B cells and medullary thymic epithelial cells. Because B cells present exogenous Ags and superantigens (SAgs), and medullary thymic epithelial cells are specialized APC for self Ags during negative selection in the thymus, we have hypothesized that H2-O might play a role in MHC class II-restricted SAg and self Ag presentation. In this study, we demonstrate that H2-O expression inhibits presentation of the bacterial SAgs staphylococcal enterotoxins A and B to four SAg-reactive T hybridoma cells. In contrast, H2-O has no effect on presentation of endogenous self Ags, as measured by tumorigenicity in vivo and Ag presentation to three self Ag-specific T hybridoma cells. Additional experiments suggest that H2-O inhibits presentation of exogenous Ags by both newly synthesized and recycling MHC class II molecules. These data suggest H2-O may have a physiological role in tolerance induction and SAg-mediated toxic shock.

Amino Acid Sequence↗

PubMed2001

A systematic examination of the morphogenesis of calcium carbonate in the presence of a double-hydrophilic block copolymer.

In this paper, a systematic study of the influence of various experimental parameters on the morphology and size of CaCO3 crystals after room-temperature crystallization from water in the presence of poly(ethylene glycol)-block-poly(methacrylic acid) (PEG-b-PMAA) is presented. The pH of the solution, the block copolymer concentration, and the ratio [polymer]/[CaCO3] turned out to be important parameters for the morphogenesis of CaCO3, whereas a moderate increase of the ionic strength (0.016 M) had no influence. Depending on the experimental conditions, the crystal morphologies can be tuned from calcite rhombohedra via rods, ellipsoids or dumbbells to spheres. A morphology map is presented which allows the prediction of the crystal morphology from a combination of pH, and CaCO3 and polymer concentration. Morphologies reported in literature for the same system but under different crystallization conditions agree well with the predictions from the morphology map. A closer examination of the growth of polycrystalline macroscopic CaCO3 spheres by TEM and time-resolved dynamic light scattering showed that CaCO3 macrocrystals are formed from strings of aggregated amorphous nanoparticles and then recrystallize as dumbbell-shaped or spherical calcite macrocrystal.

Calcium Carbonate↗

PubMed2001

Chromosome healing by addition of telomeric repeats in wheat occurs during the first mitotic divisions of the sporophyte and is a gradual process.

Alien gametocidal chromosomes cause extensive chromosome breakage prior to S-phase in the first mitotic division of gametophytes lacking the alien chromosome. The broken chromosomes may be healed either by addition of telomeric repeats in the gametophyte or undergo fusions to form dicentric or translocation chromosomes. We show that dicentric chromosomes undergo breakage fusion-bridge (BFB) cycles in the first few mitotic divisions of the sporophyte, are partially healed before the germ line differentiation regimen, and are healed completely in the ensuing gametophytic stage. The gametocidal factor on chromosome 4Mg of Aegilops geniculata was used to induce dicentrics involving the satellite chromosomes1B and 6B of wheat, Triticum aestivum. The dicentrics 1BS x 1BL-2AL x 2AS and 6BS x 6BL-4BL x 4BS initiated BFB cycles that ceased 2 to 4 weeks after seed germination. At the end of the BFB cycles, we observed deficient 1B and 6B chromosomes with breakpoints in proximal regions of the 1BL and 6BL arms. The process of chromosome healing was analyzed in root tip meristems, at meiotic metaphase I, and in the derived progenies by fluorescence in-situ hybridization analysis using a telomeric probe pAtT4. The results show that chromosome healing in wheat occurs during very early mitotic divisions in the sporophyte by de-novo addition of telomeric repeats and is a gradual process. Broken chromosome ends have to pass through several cell divisions in the sporophyte to acquire the full telomeric repeat length.

Cell Differentiation↗

PubMed2001

[Determination of serum soluble interleukin-6 receptor and soluble gp130 levels in patient with pregnancy induced hypertension and its significance].

OBJECTIVE: To observe the changes of serum soluble interleukin-6 receptor (sIL-6R) and soluble gp130 (sgp130) in patients with pregnancy induced hypertension. METHODS: Enzyme linked immunosorbent assay (ELISA) was used to determine serum sIL-6R and sgp130 levels in 40 patients with pregnancy induced hypertension (study group), 20 normal non-pregnant women (control group I) and 20 normal pregnant women (control group II). RESULTS: In study group, sIL-6R was (196.7 +/- 12.9) micrograms/L and sgp130 was (379.4 +/- 79.3) micrograms/L. In control group I, sIL-6R was (174.8 +/- 46.2) micrograms/L and sgp130 was (273.6 +/- 28.3) micrograms/L. In control group II, sIL-6R was (174.4 +/- 48.3) micrograms/L and sgp130 was (254.4 +/- 34.7) micrograms/L. SIL-6R and sgp 130 were higher in study group than those in control groups with significant difference (P < 0.01). In study group, the more severe the patients, the higher the sIL-6R and sgp130 levels. There was significant difference (P < 0.01). There was no difference in sIL-6R and sgp130 levels between control groups (P > 0.05). CONCLUSIONS: Serum sIL-6R and sgp130 levels are related to the development of pregnancy induced hypertension.

Adult↗

PubMed2001

[Value of P-glycoprotein and glutathione S-transferase-pi as chemo-resistant indicators in ovarian cancers].

OBJECTIVE: This study was conducted to assess the predictive value of P-glycoprotein (P-gp) and glutathione S-transferase-pi(GST-pi) as indicators of resistance to chemotherapy in ovarian cancers. METHODS: Expressions of P-gp and GST-pi were immunohistochemically studied in paraffin sections from 30 normal ovaries and 74 resected specimens of primary epithelial ovarian cancer from patients who had not received any chemotherapy before surgery. RESULTS: There were no detectable P-gp or GST-pi expression in the 30 patients with normal ovaries. In 74 cases of ovarian cancer tissue, P-gp was positive in 14 (18.9%) and GST-pi positive in 55 (74.3%) showing a highly significant correlation (P < 0.01). However, expression of P-gp and GST-pi was not associated with any of the clinicopathological parameters, such as clinical stage, histologic or tumor grade (P > 0.05). The evaluation of chemotherapy for postoperative residual ovarian cancer patients showed that all the six lesions showing P-gp positive were drug-resistant whereas only nine of the twenty-one tumors showing negative results were drug-resistant. Of 27 clinically measurable resected lesions, this difference in the response rates of the two groups was significant (P < 0.05). The predictive value of positive P-gp stain for drug resistance was 100% (6/6), and that of negative stain for objective responders was 57.1%(12/21). The response rate to chemotherapy of the GST-pi positive group (13.3%-2/15) was significantly lower than that of the SGT-pi negative group (83.3%-10/12, P < 0.01). The predictive value of positive GST-pi stain for drug resistance was 86.7%(13/15) and that of negative stain for objective responders was 83.3%(10/12). The survival rates of P-gp negative and GST-pi negative tumor patients were significantly higher than those of P-gp positive and GST-pi positive tumor patients (P < 0.01, P < 0.05, respectively). CONCLUSION: These data suggest that P-gp and GST-pi expression in tumor cells are related to drug resistance in epithelial ovarian cancer. They are useful indicators of resistance to chemotherapy.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed2001

[The development of endoscope workstation].

This paper introduces an endoscope workstation, which solved the weak points of multimedia endoscope database used by most hospitals. The endoscope workstation was built on pedal-switch and NTFS file system. This paper also Introduces how to make program optimal and quick inputting. The workstation has promoted the efficiency of the doctor's operation.

Computer Security↗

PubMed2000

Movement of the decoding region of the 16 S ribosomal RNA accompanies tRNA translocation.

The ribosome undergoes pronounced periodic conformational changes during protein synthesis. Of particular importance are those occurring around the decoding site, the region of the 16 S rRNA interacting with the mRNA-(tRNA)(2) complex. We have incorporated structural information from X-ray crystallography and nuclear magnetic resonance into cryo-electron microscopic maps of ribosomal complexes designed to capture structural changes at the translocation step of the polypeptide elongation cycle. The A-site region of the decoding site actively participates in the translocation of the tRNA from the A to the P-site upon GTP hydrolysis by elongation factor G, shifting approximately 8 A toward the P-site. This implies that elongation factor G actively pushes both the decoding site and the mRNA/tRNA complex during translocation.

Base Sequence↗

PubMed2000

Tumor cells present MHC class II-restricted nuclear and mitochondrial antigens and are the predominant antigen presenting cells in vivo.

MHC class II-restricted tumor Ags presented by class II(+) tumor cells identified to date are derived from proteins expressed in the cytoplasm or plasma membrane of tumor cells. It is unclear whether MHC class II(+) tumor cells present class II-restricted epitopes derived from other intracellular compartments, such as nuclei and/or mitochondria, and whether class II(+) tumor cells directly present Ag in vivo. To address these questions, a model Ag, hen egg lysozyme, was targeted to various subcellular compartments of mouse sarcoma cells, and the resulting cells were tested for presentation of three lysozyme epitopes in vitro and for presentation of nuclear Ag in vivo. In in vitro studies, Ags localized to all tested compartments (nuclei, cytoplasm, mitochondria, and endoplasmic reticulum) are presented in the absence invariant chain and H-2M. Coexpression of invariant chain and H-2M inhibit presentation of some, but not all, of the epitopes. In vivo studies demonstrate that class II(+) tumor cells, and not host-derived cells, are the predominant APC for class II-restricted nuclear Ags. Because class II(+) tumor cells are effective APC in vivo and probably present novel tumor Ag epitopes not presented by host-derived APC, their inclusion in cancer vaccines may enhance activation of tumor-reactive CD4(+) T cells.

Amino Acid Sequence↗

PubMed2000

Intracellular processing of endothelial nitric oxide synthase isoforms associated with differences in severity of cardiopulmonary diseases: cleavage of proteins with aspartate vs. glutamate at position 298.

An endothelial nitric oxide synthase (eNOS) polymorphism in exon 7 (894 G/T) resulting in glutamate or aspartate, respectively, at position 298 on the protein is correlated with severity of cardiopulmonary diseases. Because glutamate and aspartate are considered to be conservative replacements, the polymorphism was thought to be a marker for a functional locus elsewhere in the gene. We now show in transfected cells, primary human endothelial cells, and human hearts, that eNOS with aspartate, but not glutamate, at position 298 is cleaved, resulting in the generation of 100-kDa and 35-kDa products. Recombinant or native eNOS was examined by immunoblotting either in lysates (COS7) or after partial purification over 2',5'-ADP-Sepharose and calmodulin-Sepharose. Immunoblotting after SDS/PAGE with a carboxyl-terminal antibody showed a single major protein band in the predicted position for eNOS at 135 kDa. An additional band at approximately 100 kDa was present only in the recombinant 298Asp eNOS and in the eNOS synthesized by primary cells and heart tissue with a G/T genotype. Using an eNOS amino-terminal-specific antibody, an immunoreactive band at approximately 35 kDa, corresponding to the residual N-terminal cleavage fragment, was observed in those cells with a T genotype. Thus, eNOS with aspartate but not glutamate at position 298 is cleaved, resulting in the generation of N-terminal 35-kDa and C-terminal 100-kDa fragments. Thus, the eNOS gene with polymorphisms at nucleotide 894 generates protein products with differing susceptibility to cleavage, suggesting that, in contrast to prior predictions, this polymorphism has a functional effect on the eNOS protein.

Animals↗

PubMed2000

Crystal Design of Barium Sulfate using Double-Hydrophilic Block Copolymers.

Peach, peanut, fiber, and flower (see picture) crystal morphologies are achieved from the precipitation of simple minerals in the presence of specifically adsorbing polymers. These crystal design effects are illustrated using BaSO(4) and double-hydrophilic block copolymers, the latter featuring carboxylate, sulfonate, phosphonate, and aspartic acid groups.

Journal Article↗

PubMed2000

CpG-specific common commitment in caspase-dependent and -independent cell deaths.

Cell death in mammals seems to have caspase-dependent and -independent pathways unlike that in Caenorhabditis elegans where CED-3 protease activation is the central command. A recent suggestion to define apoptosis as the caspase-dependent or caspase-committed cell death form and leave cell death committed by other pathways as just cell death was meant to categorize the apparent divergence in mammalian cell death pathways. However, we show CpG oligonucleotides (ODN) blocking caspase-dependent fas(CD95) ligand-mediated apoptosis as well as caspase-independent etoposide-mediated apoptosis and etoposide-zVAD-mediated necrosis. CpG specificity was demonstrated by reversing the CpG motif or replacing it with a methylated motif (mCpG) which failed to inhibit. CpG ODN blocked CpG-specific DNA cleavage by rare-cutting NotI restriction, which produced a megabase cleavage pattern similar to that in the fasL and etoposide cell death inductions. CpG ODN inhibition was similar to that by CpG-specific SssI methylase. A common CpG-specific commitment point preceding caspase-dependent and -independent cell death pathways was suggested. CpG-specific modulation is a key epigenetic mechanism in genomic imprinting, resisting nuclease restriction, and patterning of chromatin conformations. It is now shown to have a powerful effect modulating cell death.

Amino Acid Chloromethyl Ketones↗