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Biomedical subjects

Z Liu

Publications and source records attributed to Z Liu.

At least 235 records · Page 13Linked to original sources
PubMed2001

Correlation between transcriptome and interactome mapping data from Saccharomyces cerevisiae.

Genomic and proteomic approaches can provide hypotheses concerning function for the large number of genes predicted from genome sequences. Because of the artificial nature of the assays, however, the information from these high-throughput approaches should be considered with caution. Although it is possible that more meaningful hypotheses could be formulated by integrating the data from various functional genomic and proteomic projects, it has yet to be seen to what extent the data can be correlated and how such integration can be achieved. We developed a 'transcriptome-interactome correlation mapping' strategy to compare the interactions between proteins encoded by genes that belong to common expression-profiling clusters with those between proteins encoded by genes that belong to different clusters. Using this strategy with currently available data sets for Saccharomyces cerevisiae, we provide the first global evidence that genes with similar expression profiles are more likely to encode interacting proteins. We show how this correlation between transcriptome and interactome data can be used to improve the quality of hypotheses based on the information from both approaches. The strategy described here may help to integrate other functional genomic and proteomic data, both in yeast and in higher organisms.

Fungal Proteins↗
PubMed2001

Sexual dimorphism in relationship of serum leptin and relative weight for the standard in normal-weight, but not in overweight, children as well as adolescents.

OBJECTIVE: To demonstrate sexual dimorphism in serum leptin levels not only during puberty, but also in childhood in Japan. DESIGN: Cross-sectional study. SETTING: Hamamatsu-Hokuen study in Japan. SUBJECTS: Body weight and height were measured in normal-weight Japanese children and adolescents (143 boys, 178 girls), and 161 boys and 129 girls whose percentage of overweight for the standard (%Wt) was more than+25%. Serum leptin levels were compared with %Wt. Subjects were divided into group 1 (6-10 y of age) and group 2 (11-15 y of age) according to their age. RESULTS: In overweight subjects, leptin was more highly correlated with %Wt in boys of group 2 (r=0.67, P<0.0001) than group 1 (r=0.32, P=0.004). In girls as well, a correlation coefficient was greater in group 2 (r=0.67, P<0.0001) than group 1 (r=0.44, P=0.0011). In normal-weight boys, there was no significant correlation between serum leptin and %Wt both in groups 1 and 2. On the contrary, statistical significance was demonstrated in the correlation between serum leptin and %Wt in group 1 (r=0.31, P=0.0019) and group 2 (r=0.35, P=0.0014) as well as in the total normal-weight girls (r=0.28, P=0.0011). CONCLUSIONS: It is suggested that sexual dimorphism is present in serum leptin levels, especially when compared to weight, as early as during childhood.

Adolescent↗
PubMed2001

Effects of anti-tumour necrosis factor, interleukin-10 and antibiotic therapy in the indometacin-induced bowel inflammation rat model.

BACKGROUND: The administration of indometacin to rats increases intestinal permeability and induces inflammatory pathology of the small bowel. This represents a potential model for Crohn's disease. AIMS: To analyse the pathogenic role of T cells, tumour necrosis factor and bacterial flora in indometacin-induced changes in small bowel permeability and inflammation. METHODS: Rats were given indometacin, 13 mg/kg, on day 1 and day 2. The effects of antibiotic (metronidazole, aztreonam and amoxicillin/clavulanic acid), anti- tumour necrosis factor and interleukin-10 therapy were evaluated. The parameters used were weight change, serum haemoglobin, chromium-51 ethylenediaminetetra-acetate permeability and macro-and microscopic score on day 5. Results in conventionally harboured rats were compared with those in T-cell-free rats. Additional in vitro experiments were carried out to test the effect of metronidazole on tumour necrosis factor production. RESULTS: Indometacin administration resulted in small bowel ulcers and inflammation, independently of T cells. Metronidazole was more potent than amoxicillin/clavulanic acid and anti-tumour necrosis factor in improving the indometacin-induced small bowel inflammation. Only part of the efficacy was through improvement of increased intestinal permeability. Aztreonam and interleukin-10 had no effect. Metronidazole also suppressed in vitro lipopolysaccharide-induced tumour necrosis factor production, suggesting a therapeutic effect of this drug through the inhibition of tumour necrosis factor. CONCLUSIONS: These data implicate anaerobic bacteria and tumour necrosis factor production, but not T cells, as essential elements of the pathogenesis of indometacin-induced small bowel inflammation. Tumour necrosis factor is also involved in the change in intestinal permeability. Metronidazole was the most efficacious drug in this model, probably because it suppressed anaerobic bacteria and directly inhibited tumour necrosis factor production.

Amoxicillin-Potassium Clavulanate Combination↗
PubMed2001

Transcriptome of channel catfish (Ictalurus punctatus): initial analysis of genes and expression profiles of the head kidney.

Analysis of expressed sequence tags (ESTs) is an efficient approach for gene discovery, expression profiling, and development of resources useful for functional genomics studies. As part of the transcriptome analysis in channel catfish (Ictalurus punctatus), we have conducted EST analysis using a cDNA library made from the head kidney. We analysed 2228 EST clones. Orthologues were established for 1495 (67.1%) clones representing 748 genes, of which 545 (36.5%) clones were singletons. The remaining 733 (32.9%) clones represent unknown gene clones, for which the number of genes has not yet been determined.

Animals↗
PubMed2001

Arabidopsis UVH3 gene is a homolog of the Saccharomyces cerevisiae RAD2 and human XPG DNA repair genes.

To identify mechanisms of DNA repair in Arabidopsis thaliana, we have analyzed a mutant (uvh3) which exhibits increased sensitivity to ultraviolet (UV) light, H2O2 and ionizing radiation and displays a premature senescence phenotype. The uvh3 locus was mapped within chromosome III to the GL1 locus. A cosmid contig of the GL1 region was constructed, and individual cosmids were used to transform uvh3 mutant plants. Cosmid N9 was found to confer UV-resistance, H2O2-resistance and a normal senescence phenotype following transformation, indicating that the UVH3 gene is located on this cosmid and that all three phenotypes are due to the same mutation. Analysis of cosmid N9 sequences identified a gene showing strong similarity to two homologous repair genes, RAD2 (Saccharomyces cerevisiae) and XPG (human), which encode an endonuclease required for nucleotide excision repair of UV-damage. The uvh3 mutant was shown to carry a nonsense mutation in the coding region of the AtRAD2/XPG gene, thus revealing that the UVH3 gene encodes the AtRAD2/XPG gene product. In humans, the homologous XPG protein is also involved in removal of oxygen-damaged nucleotides by base excision repair. We discuss the possibility that the increased sensitivity of the uvh3 mutant to H2O2 and the premature senescence phenotype might result from failure to repair oxygen damage in plant tissues. Finally, we show that the AtRAD2/XPG gene is expressed at moderate levels in all plant tissues.

Amino Acid Sequence↗
PubMed2001

Three-dimensional echocardiography of left atrial appendage thrombus.

Transesophageal echocardiography (TEE) is superior to transthoracic echocardiography (TTE) in evaluating the left atrial appendage (LAA) as a potential cardiac source of embolus in patients with stroke. We describe two such patients in whom a TEE and subsequently a three-dimensional (3-D) reconstruction of the LAA were performed. These case reports show that 3-D echocardiography provides better visualization of LAA anatomy, and that a 3-D description of LAA morphology may be the basis of describing normal and abnormal LAA.

Aged↗
PubMed2001

Authentication of Chinese crude drug, Gecko, by allele-specific diagnostic PCR.

Based on the sequences of the mitochondrial 12S rRNA gene fragment of 17 samples from Gekkonidae, Salamandridae, Agamidae and Hynobiidae, respectively, a pair of allele-specific primers was designed for differentiating the Chinese medicinal material Gecko from its adulterants by PCR. The results of amplification with the primers indicate that amplicons from the templates of Gekko gecko were clearly revealed by agarose gel electrophoresis, whereas no evident amplicons were found from other species. The primers were employed to identify crude drug samples from different sources. Among a total of 9 samples, 3 were diagnosed as genuine Gecko. This result is consistent with morphological identification and DNA sequence analyses.

Animals↗
PubMed2001

Ultraharmonic myocardial contrast imaging: in vivo experimental and clinical data from a novel technique.

Myocardial contrast echocardiography (MCE) with high-mechanical-index (MI), triggered harmonic imaging is the best-established technique to date for the assessment of myocardial perfusion. A high signal-to-noise ratio, which is significantly influenced by precontrast tissue signals, is an important prerequisite. Our goal was to evaluate the efficacy of ultraharmonic MCE, a technique that rejects tissue signals by receiving signals beyond the second but below the third harmonic. Imaging was performed in 6 closed-chest dogs and in 15 healthy volunteers (11 of whom also had dipyridamole stress). Analyses of videointensity (VI) confirmed uniformly low precontrast tissue VI, a significant increase of postcontrast VI (before and after dipyridamole), and a significant decrease in VI after microbubble destruction. We conclude that ultraharmonic MCE produces low precontrast tissue signals, thus optimizing postcontrast myocardial opacification, and exhibits efficient microbubble destruction with use of multiple-frame triggering. Thus this new technique opens up a new possibility of further optimizing coronary microcirculation imaging with microbubbles.

Adult↗
PubMed2001

Mannose-binding lectin gene polymorphism associated with the patterns of glomerular immune deposition in IgA nephropathy.

OBJECTIVE: To elucidate the genetic background underlying the diversity of mesangial immune deposition in IgA nephropathy (IgAN), we investigated the distribution of mannose-binding lectin (MBL) gene codon 54 polymorphism and serum MBL levels in IgAN patients. METHODS: Seventy-seven IgAN patients with glomerular IgA and C3 deposits (Group A) and 70 with glomerular IgA, IgG, IgM, C3 and Clq deposits (Group AGM) were included in the present study. Control group consisted of 140 normal adults. MBL genotypes were investigated by polymerase chain reaction and restriction fragment length polymorphism. Serum MBL levels with different genotypes were also assayed in some subjects. RESULTS: The variant allele (GAC) was markedly associated with Group AGM (OR = 1.95, 95% C.I.: 1.06-3.58). In both Group A and Group AGM, more patients carrying the variant allele had episodes of upper respiratory or gastrointestinal infections prior to onset or exacerbation of IgAN than wild homozygotes (GGC/GGC). In addition, a significant difference in serum MBL level was also observed between wild homozygotes and heterozygotes (GGC/GAC) (GGC/GGC > GGC/GAC) (p<0.0001) in all groups, while there was no difference for subjects with the same genotypes among the three groups (p > 0.05). Serum MBL levels of the rare variant homozygotes approached zero. CONCLUSIONS: Our findings provide evidence that the host defense molecule, MBL, may be involved in the formation of the diversity of glomerular immune deposition in IgAN. Genetic deficiency of MBL may partially account for abundant immune deposits in some IgAN patients.

Adult↗
PubMed2001

The use of psychoactive substances among adolescent students in an area in the south-west of China.

AIM: To survey drug/psychoactive substance use among adolescent students in a south-west province of China. DESIGN: A cluster sample was drawn from this province of nine districts or cities. Each district/city provided two schools from grade 11 senior high school, A total of 18 schools were selected randomly. FINDINGS: A total of 2649 students completed this self-report questionnaire, mean age 17.1 +/- 0.9 years. The response rate was 92.7-95.6% for each of the specific substances or drugs. The 'life-time prevalences of regular substance use' (at least 15 times during in any one month) were, in rank order of prevalence: tobacco 6.3%, non-steroid anti-inflammatory drugs (NSAID) 2.9%, alcohol 2.9%, solvent 0.3%, sedative/hypnotic 0.2% and cannabis 0.04%. The life-time prevalences of at least some use were: alcohol 66.1%, NSAID 59.3%, tobacco 27.4%, sedative/hypnotic 5.2%, heroin 3.1%, solvents 2.8%, amphetamine-type stimulants (ATS) 0.7% and cannabis 0.3%. The 'prevalences of current regular use' (at least 15 times in the past month) were: tobacco 4.2%, alcohol 1.6%, NSAID 0.8%, sedative/hypnotic 0.1%, solvents 0.1% and cannabis 0.1%. The 'prevalences of current use at any level' were: alcohol 15.2%, NSAID 9.6%, tobacco 7.1%, sedative/hypnotic 0.5%, solvents 0.4%, cannabis 0.1%, heroin 0.1%, and ATS 0.04%. The median age at onset substance use was between 10.7 and 13.4 9.6%. CONCLUSIONS: Drug misuse has appeared among teenage students in this area. The most widely used substances were alcohol and cigarettes. The rates of solvent, tobacco and alcohol use among males were substantially higher than in females.

Adolescent↗
PubMed2001

Identification of various phases in HRTEM images of MgO-PSZ.

Magnesia partially stabilized zirconia (MgO-PSZ) is one of the most commonly used engineering ceramics based on zirconia. A detailed discussion about how to identify the various phases in high-resolution transmission electron microscopy images of this material is presented. It shows that in some cases, standard procedures of image simulation are inadequate to interpret these images. By including the effect of astigmatism in both experimental and simulated images, together with the digital Fourier transforms of the images, orthorhombic ZrO2 in [001] orientation was identified. The delta-phase, which has a marked effect on the thermomechanical properties of MgO-PSZ, can most easily be identified by high-resolution imaging in the [130]c zone that coincides with a low-index zone axis of the delta-phase.

Journal Article↗
PubMed2001

A buckwheat protein product suppresses 1,2-dimethylhydrazine-induced colon carcinogenesis in rats by reducing cell proliferation.

This study was conducted to examine the effect of consumption of buckwheat protein product (BWP) on 1,2-dimethylhydrazine (DMH)-induced colon tumor in rats. Male growing Sprague-Dawley rats were fed diets containing either casein or BWP (net protein level, 200 g/kg; n = 20/group) for 124 d. The rats were gavaged weekly with DMH (20 mg/kg body) for the first 8 wk. Food intake and growth were unaffected by dietary manipulation. Dietary BWP caused a 47% reduction in the incidence of colonic adenocarcinoma (P < 0.05), but did not affect the incidence of colonic adenomas. BWP intake tended to reduce the number of colon adenocarcinomas (P = 0.16). Consumption of BWP significantly reduced cell proliferation and expression of c-myc and c-fos proteins in colonic epithelium. The results suggest that dietary BWP has a protective effect against DMH-induced colon carcinogenesis in rats by reducing cell proliferation.

1,2-Dimethylhydrazine↗
PubMed2001

Ecosystem respiration in a young ponderosa pine plantation in the Sierra Nevada Mountains, California.

We estimated total ecosystem respiration from a ponderosa pine (Pinus ponderosa Dougl. ex Laws.) plantation in the Sierra Nevada Mountains near Georgetown, California, from June to October, 1998. We apportioned ecosystem respiration among heterotrophic, root, stem and foliage based on relationships for each component that considered microclimate and vegetation characteristics. We measured each respiration component at selected sampling points, and scaled the measurements up to the ecosystem based on modeled relationships. Over the study period, total mean ecosystem respiration was 5.7 +/- 1.3 mumol m-2 s-1 (based on daily mean), comprising about 67% from soil-surface CO2 efflux, 10% from stem and branch respiration and 23% from foliage respiration. Shrub leaves contributed about 24% to total foliage respiration, and current-year needles (1998 age class) accounted for 40% of total tree needle respiration. Root respiration accounted for 47% of soil-surface CO2 efflux. We conclude that ecosystem respiration can be estimated based on daily mean air and soil temperatures through exponential relationships with r2 values of 0.85 and 0.87, respectively. When based on both air and soil temperatures, about 91% of the variation in total ecosystem respiration could be explained by a linear regression.

Biomass↗
PubMed2001

Expression of the receptor tyrosine kinases, epidermal growth factor receptor, ErbB2, and ErbB3, in human ocular surface epithelia.

PURPOSE: To investigate the distribution and relative level of expression of the receptor tyrosine kinases, epidermal growth factor receptor (EGFR), ErbB2 and ErbB3, in human ocular surface epithelia. METHODS: Immunofluorescent staining was performed to identify expression of the EGFR, ErbB2 and ErbB3 in the corneal, limbal and conjunctival epithelium in tissue sections and impression cytologies taken from normal human eyes. Western blotting was undertaken to confirm the results of immunofluorescent staining. RESULTS: The three receptor tyrosine kinases, EGFR, ErbB2 and ErbB3, were detected in human corneal, limbal and conjunctival epithelia by immunofluorescent staining. Strong staining for the EGFR was observed in the basal epithelial cells at all 3 sites and throughout the corneal epithelium. Minimal or no staining for the EGFR was observed in the superficial conjunctival and limbal epithelia. The strongest staining for ErbB2 and ErbB3 was observed in the superficial ocular surface epithelium. All three receptors were detected in the corneal, limbal and conjunctival epithelium by western blot. CONCLUSION: EGFR, ErbB2 and ErbB3 are expressed by the ocular surface epithelia. EGFR is preferentially expressed by the basal epithelial cells that have the greatest proliferative potential. In contrast, ErbB2 and ErbB3 are preferentially expressed by the superficial differentiated ocular surface epithelia.

Animals↗
PubMed2001

Saccharopolyspora flava sp. nov. and Saccharopolyspora thermophila sp.nov., novel actinomycetes from soil.

The generic position of two aerobic, Gram-positive, non-acid-alcohol-fast actinomycetes was established following the isolation of their PCR-amplified 16S rRNA genes and alignment of the resultant sequences with the corresponding sequences from representatives of the families Actinosynnemataceae and Pseudonocardiaceae. The assignment of the organisms to the genus Saccharopolyspora was strongly supported by chemotaxonomic and morphological data. The strains were distinguished both from one another and from representatives of validly described Saccharopolyspora species on the basis of a number of phenotypic properties. It is proposed that the organisms, strains 07T (= AS4.1520T = IFO 16345T = JCM 10665T) and 216T (= AS4.1511T = IFO 16346T = JCM 10664T), be classified in the genus Saccharopolyspora as Saccharopolyspora flava sp. nov. and Saccharopolyspora thermophila sp. nov., respectively.

Bacterial Typing Techniques↗
PubMed2001

Amycolatopsis rubida sp. nov., a new Amycolatopsis species from soil.

The taxonomic position of a soil isolate, strain 13.4T, was established using a polyphasic approach. The organism was found to have chemical and morphological properties consistent with its classification in the genus Amycolatopsis. Phylogenetic analysis of the strain based on its 16S rDNA sequence showed that it forms a distinct phyletic line within members of the genus Amycolatopsis. The organism was also readily distinguished from the type strains of all validly described Amycolatopsis species by its phenotypic features. The name Amycolatopsis rubida sp. nov. is proposed for this new species. The type strain is strain 13.4T (= AS 4.1541T = JCM 10871T).

Actinomycetales↗