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Biomedical subjects

W Zhu

Publications and source records attributed to W Zhu.

At least 181 records · Page 10Linked to original sources
PubMed1999

Writing Chinese characters and success on Mental Rotation Test.

Our recent study with Chinese and Chinese-American undergraduates indicated that writing Chinese characters was associated with better performance on the Piagetian Water-Level Task for Chinese-American men. The current study investigated whether the same effects would apply to the Vandenberg Mental Rotation Test. Two alternative hypotheses (bilingualism and birth place) were also tested. Participants were two groups of Chinese-American undergraduates: 48 writers of Chinese (21 men, 27 women) and 130 nonwriters of Chinese (58 men, 72 women). Analysis suggested that writing Chinese and birth in the USA contributed significantly to the success on Mental Rotation Test. Students who were born in the USA and able to write Chinese scored the highest on this test. Being bilingual was not associated with performance on the Mental Rotation Test. Men performed significantly better than women.

Analysis of Variance↗
PubMed1999

[Correlation analysis of (G + C)% of coding sequence and thermostability of xylose isomerase of thermophiles].

Statistical analysis about amino acids and coding sequence of xylose isomerase were performed in a number of thermophiles and mesophiles. It was found that there are correlations between the (G + C)% of the coding sequence and that of 1st, 2nd and 3rd position of the code of amino acids. There were also positive (for hydrophobic amino acids) and negative (for hydrophilic amino acids) correlation between the content of individual amino acids in the enzyme protein and the (G + C)% of their respective coding sequence. It speaks for the notion that high content of (G + C) in the coding sequence tends to increase the thermostability of the corresponding protein. The results in the statistical analysis of amino acid substitutions leading to change in thermostability of the protein may also be interpreted in the same way. An increase in the (G + C)% of DNA of a bacterium can therefore not only increase the thermostability of DNA itself but its proteins as well. Evolutionary consequence concerning thermophily and coding system are discussed.

Aldose-Ketose Isomerases↗
PubMed1999

Clinicopathologic, immunophenotypic and ultrastructrual analyses of ATLL patients with cutaneous involvement.

OBJECTIVE: To study 4 cases of adult T-cell leukemia/lymphoma (ATLL) associated with cutaneous lesions for clinicopathology, immunophenotype, human T-cell leukemia/lymphoma virus type I (HTLV-I) provirus DNA and their ultrastructure. At the same time, HTLV-I provirus DNA of ATLL patients were also compared with 18 cases of cutaneous lymphoma (CL), two cases of actinic reticuloid as well as two cases of lymphocytic infiltration. METHODS: Immunohistochemistry studies were carried out on the infiltrating cells using monoclonal antibodies against CD45-RO, CD20, CD68 on paraffin-embedded sections by ABC method and using monoclonal antibodies against CD3, CD4 and CD8 with indirect immunofluorescence (IIF) on frozen sections. Skin biopsies were examined by electron microscope. Serum and bone marrow cells were tested for antibodies against HTLV-I-associated antigen by IIF, and HTLV-I provirus DNA was examined by PCR method. RESULTS: The research showed four patients with ATLL manifesting cutaneous lesions, were subsequently found with additional systemic symptoms, as extensively enlarged superficial lymph node, abnormal increased IL-2 receptor, flower-like cells in their peripheral blood and marrow. The HTLV-I provirus DNA was positive in the peripheral blood, bone marrow, cutaneous lesions and lymph node biopsy specimens by using PCR amplification of specific HTLV-I fragment while 18 cases of the CL were negative for HTLV-I. The special ultrastructure of skin lesions was also found in ATLL patients. CONCLUSIONS: The cutaneous involvement in ATLL is a type of cutaneous T cell lymphoma (CTCL) but shows some differential immunological markers for differential diagnosis. The examination of HTLV-I antibodies or HTLV-I provirus DNA is necessary for diagnosis of ATLL. The ultrastructural characteristics in skin lesions of ATLL were of atypical lymphocytes and mononuclear cells invading the epidermis, and the mononuclear cells are possessing the phagocytic function and phagocytizing the degenerated epidermic cells or lymphocytes.

Aged↗
PubMed1999

Isolation and identification of Mycoplasma genitalium from high risk populations of sexually transmitted diseases in China.

OBJECTIVE: To investigate Mycoplasma genitalium (Mg) infection in high risk populations of sexually transmitted diseases (STDs) in China by means of culture, Mg-DNA detection, observation under an electron microscope (EM) and an atomic force microscope (AFM). METHODS: 227 urogenital specimens taken from both patients in clinics and high risk populations of STDs in Beijing, Nanjing and Shanghai areas were cultured in SP-4 medium for isolation of Mg. Suspicious positive strains were identified first by PCR technique which could amplify the special DNA fragments of Mg adhesion protein (Mg-Pa) and 16S-rRNA sequences. The morphologic features of Mg were observed under EM and AFM. RESULTS: Eight strains were isolated from the 227 specimens, the total positive rate was 3.52%. The isolated strains met the criteria of growth and metabolic conditions required by Mg. Specific fragments of Mg-DNA (374 bp based on Mg-Pa and 402 bp on 16S-rRNA primers, respectively) could be amplified from both the isolates and the genital secretions. Under EM and AFM, Mg showed different shapes, including flask, pear, spindle and globe shape. The typical shape of Mg was flask or pear shape with projecting neck portion and broadened terminal structure under EM and with constrictive ring between the neck and body under AFM. CONCLUSION: Mg infection exists in high risk populations of STDs in China. We highly suggest the use of AFM in dermatological study.

Cervix Uteri↗
PubMed1999

[Postprandial triglyceridemia and carotid atherosclerosis in male patients with coronary heart disease].

OBJECTIVE: To test the effect of postprandial accumulation of triglyceride-rich lipoprotein (TGRL) on carotid artery atherosclerosis. METHODS: In 42 male cases with coronary heart disease (CHD) as verified by angiography, high density lipoprotein cholesterol and apolipoprotein B (ApoB) levels in fasting serum, serum triglyceride concentrations before and 2, 4, 6, 8 hours after a standard fat test meal were measured. Each patient underwent a carotid artery high-resolution B-mode ultrasound examination. The extent of alimentary lipemia [area under the triglyceride curve over 8 hours, TG-AUC and peak triglyceride response (TGPR)] correlated with the carotid artery intima-media thickness. RESULTS: Univariate analyses indicated both TG-AUC and TGPR had direct correlation with mean intima-media thickness measured from four well-defined vessel wall segments in the left and right carotid arteries (r = 0.45 and 0.41, both P < 0.01). After controlling for age, body mass index (BMI), triglyceride, HDL-C, and apolipoprotein B concentrations in fasting serum with multivariate stepwise regression analysis, the above correlation remained. There was an independent inverse correlation between HDL-C and carotid artery intima-media thickness. CONCLUSION: It is suggested that abnormal metabolism and clearance of postprandial TGRL can promote the progression of atherosclerosis.

Adult↗
PubMed1999

[A preliminary study on hepatitis E virus antibody IgG and IgM for the diagnosis of acute hepatitis E].

OBJECTIVE: To evaluate the significance of hepatitis E virus antibody (anti-HEV) IgG and IgM for the diagnosis of acute hepatitis E. METHODS: Acute phase sera from a total of 143 patients with sporadic hepatitis E in 7 cities of China were determined for anti-HEV IgM and IgG by using an enzyme-linked immunosorbent assay (EIA). 359 serial sera of 56 patients with hepatitis E and 68 serial sera of 4 rhesus macaques experimentally infected with hepatitis E virus (HEV) were also detected for anti-HEV IgG and IgM. RESULTS: In the 143 patients the positive rate of anti-HEV IgG was 100.0%, which was significantly higher than that of anti-HEV IgM (73.4%, 105/143). 97.2% of anti-HEV IgG positive patients had a titer over 1:40. The positive rate of anti-HEV IgM increased with the titer of anti-HEV IgG in sera. It was 0% (0/4), 44.4% (8/18) and 80.2% (97/121), respectively in patients with the anti-HEV IgG titer of 1:20, 1:40 and >or=1:80 (P < 0.001). All the anti-HEV IgM positive patients were also anti-HEV IgG positive. No patients were found to be anti-HEV IgM positive alone. Anti-HEV IgG was detected as early as 2 days after onset of the disease, with a cumulative positive seroconversion rate of 100% by 1 month. The negative seroconversion rate of anti-HEV IgG increased with course of the disease and 43.3% of the patients lost their anti-HEV IgG by 6 months after illness. Though anti-HEV IgM also seroconverted at the same time as anti-HEV IgG, its cumulative positive seroconversion rate was only 71.4% and declined rapidly. Up to 37.5% of anti-HEV IgM positive patients became negative by 1 month after onset. Similar antibody responses were observed in 4 rhesus macaques experimentally infected with HEV. CONCLUSION: It is suggested that as a result of the poor sensitivity of currently available anti-HEV IgM EIA kits, anti-HEV IgG will be a more reliable marker for the diagnosis of acute hepatitis E as compared with anti-HEV IgM.

Acute Disease↗
PubMed1999

[mRNA and protein expression of apoptosis-regulating gene bcl-x in lymphomas].

OBJECTIVE: To observe mRNA and protein expression of bcl-x and explore the role of bcl-x in the regulation of apoptosis and oncogenesis and their value in differential diagnosis of lymphomas. METHODS: Reverse transcription-polymerase chain reaction (RT-PCR) and citric acid-microwave-ABC immunohistochemistry (ICH) were used to observe mRNA transcription forms and protein distributions of bcl-x in 30 frozen tissues and 109 paraffin embedded tissues (both including reactive hyperplasia and common types of lymphoma). RESULTS: RT-PCR revealed that all 30 frozen cases showed bcl-x transcription, of which 29 had bcl-x1 band and 13 had bcl-xs band. Bcl-x1 band was always stronger than bcl-xs band. IHC found that 97/109 cases had fine positive bcl-x granules in the cytoplasm. In lymphoid reactive hyperplasia, bcl-x exhibited weak immunoactivity in cells located in the germinal centers and interfollicular regions of the nodes but not in the mantle zone lymphocytes which surround germinal centers. In lymphomas, bcl-x immunoactivity was always strong and diffuse. The staining fractions in different types of lymphomas were significantly higher than those in lymphoid reactive hyperplasias (P > 0.05), but no significant difference was found between the positive rate and staining fraction of different types of lymphomas. CONCLUSION: Bcl-x shows active mRNA transcription and high protein expression in lymphomas. The long isoform of bcl-x (bcl-xl) is the predominant expression. The characteristics of bcl-x protein expression may be helpful in differential diagnosis of reactive hyperplasia and lymphoma.

Apoptosis↗
PubMed1999

[Experimental study on induction of apoptosis of leukemic cells by Boswellia carterii Birdw extractive].

The purpose of the study was to investigate the apoptosis of leukemic cells induced by Boswellia Carterii Birdw(BCB). The target leukemia cell line HL60 and bone marrow leukemic cells from 30 acute non-lymphocytic leukemic(ANLL) patients (3 M1 11 M2a 10 M3 1 M4a 5 M5b) were studied. Apoptosis was detected by morphological observation, DNA electrophoresis, percentage of DNA fragmentation test and flow cytometric cell cycle analysis. It is concluded that BCB can induce apoptosis in ANLL cells and HL60 cells.

Adolescent↗
PubMed1999

[Inhibition of glutamate uptake in rat brain synaptosome by methylmercury].

The effect of methylmercury on the glutamate uptake in rat brain synaptosomes were studied in vitro by using a high affinity uptake test. The result showed that methylmercury(1 x 10(-9) -1 x 10(-4) mol/L) could decrease 3H-L-glutamate uptake in rat cerebral cortex, hippocampus, striatum and cerebellum synaptosome by 0.7%-74.4%, 7.5%-91.1%, 1.4%-76.6% and 4.4%-77.0%, respectively, in a dose-dependent manner, and their IC50 were 7, 9, 3.6, 2.2 and 4.3 x 10(-6) mol/L, respectively. It suggested that methylmercury could obviously inhibit glutamate uptake in the synaptosomes of rat brain.

Animals↗
PubMed1999

[Kinetics of the Ca(2+)-activated K+ channel in Ca2+ induced cortex neurons damage].

Ca(2+)-activated K+ channels were studied by using the patch clamp technique of single channel recordings from the primary culture fetal SD rat cortex neurons. Besides their physiologic characters, the effects of increasing cytosolic and cytoplasmic Ca2+ triggered neuronal damage were also studied. The results showed that Kca with conductance around 170PS was predominant in the rat cortex neurons. These channels almost did not open at physiologic intracellular free Ca2+ concentration (10(-8) mol/L), but was extremely activated at intracellular free Ca2+ concentration (10(-6) mol/L). So the open probabilities of the KCa in the cortex neurons obviously depended on the concentration of cytoplasmic Ca2+ and membrane potential. The KCa activated by increasing of intracellular Ca2+ during the early stage of anoxia may be a protective reaction of ischemic neurons.

Animals↗
PubMed1999

[Evaluation of immunochromatographic test in the diagnosis of Plasmodium falciparum and Plasmodium vivax].

AIM: To evaluate the effectiveness of immunochromatographic test(ICT) in detecting Plasmodium falciparum and Plasmodium vivax in malaria endemic areas. METHODS: ICT was used to detect P. falciparum and P. vivax among patients with fever in the outpatient clinics by comparason with thick blood smear method. RESULTS: The sensitivity of ICT to detect P. falciparum and P. vivax was 96.7% and 90.4%, respectively. The specificity of ICT was 98.6%, and the coincidence rate was 94.7%. There is no cross reaction between P. falciparum and P. vivax. CONCLUSION: ICT could detect P. falciparum and P. vivax simutaneously, being more rapid and simple than blood smear method.

Animals↗
PubMed1999

[Determination of metals in atmospheric particulates by atomic absorption spectrometric method (AAS) with CA-CN micropore membrane filters used for sampling].

A new sampling method of atmospheric particulates using 0.22 microm pore diameter micropore membrane filters was introduced. Copper, lead, zinc cadmium, manganese, iron, nickel and chromium in atmospheric particulates were determined by atomic absorption spectrometry. This sampling method has shown several advantages: easy, complete and fast digestion; low membrane blank; increased flexibility to surrounding temperature change; high elution recovery, standard addition recovery, precision and accuracy.

Metals↗
PubMed1998

Low-field electron emission from undoped nanostructured diamond

Strong and sustained electron emission at low electric fields was observed in undoped, nanostructured diamond. Electron emission of 10 milliamperes per square centimeter was observed at applied fields of 3 to 5 volts per micrometer. These are the lowest fields ever reported for any field-emitting material at technologically useful current densities. The emitter consists of a layer of nanometer-size diamond particulates, which is heat-treated in a hydrogen plasma. These emission characteristics are attributed to the particles' high defect density and the low electron affinity of the diamond surface. Such emitters are technologically useful, because they can be easily and economically fabricated on large substrates.

Journal Article↗
PubMed1998

A calcineurin-dependent transcriptional pathway controls skeletal muscle fiber type.

Slow- and fast-twitch myofibers of adult skeletal muscles express unique sets of muscle-specific genes, and these distinctive programs of gene expression are controlled by variations in motor neuron activity. It is well established that, as a consequence of more frequent neural stimulation, slow fibers maintain higher levels of intracellular free calcium than fast fibers, but the mechanisms by which calcium may function as a messenger linking nerve activity to changes in gene expression in skeletal muscle have been unknown. Here, fiber-type-specific gene expression in skeletal muscles is shown to be controlled by a signaling pathway that involves calcineurin, a cyclosporin-sensitive, calcium-regulated serine/threonine phosphatase. Activation of calcineurin in skeletal myocytes selectively up-regulates slow-fiber-specific gene promoters. Conversely, inhibition of calcineurin activity by administration of cyclosporin A to intact animals promotes slow-to-fast fiber transformation. Transcriptional activation of slow-fiber-specific transcription appears to be mediated by a combinatorial mechanism involving proteins of the NFAT and MEF2 families. These results identify a molecular mechanism by which different patterns of motor nerve activity promote selective changes in gene expression to establish the specialized characteristics of slow and fast myofibers.

3T3 Cells↗
PubMed1998

At the onset of transformation polyomavirus middle-T recruits shc and src to a perinuclear compartment coincident with condensation of endosomes.

To examine the early cellular changes that accompany transformation, middle-T antigen (the transforming protein of polyomavirus), was expressed from an inducible promoter in Rat2 fibroblasts and in normal diploid human fibroblast (MRC5) cells using a replication defective adenovirus vector. The earliest detectable expression of middle-T antigen correlated closely with the initial changes in cellular morphology. At this time, expression of middle-T antigen resulted in the redistribution of shc and src to a brefeldin A resistant perinuclear compartment coincident with the formation of kinase active complexes containing middle-T antigen, shc and src. The first detectable changes directly related to altered morphology was reorganization of actin filaments, and the condensation of tubular endosomes in the perinuclear region of the cell. These results suggest a potential role for perinuclear localized mT molecules in some of the morphologic changes associated with the initial phase of cellular transformation.

Adaptor Proteins, Signal Transducing↗
PubMed1998

NMR structure and comparison of the archaeal histone HFoB from the mesophile Methanobacterium formicicum with HMfB from the hyperthermophile Methanothermus fervidus.

The solution-state structure of the recombinant archaeal histone rHFoB, from the mesophile Methanobacterium formicicum, has been determined by two- and three-dimensional (3D) proton homonuclear correlated nuclear magnetic resonance (NMR) methods. On the basis of 951 nuclear Overhauser effect (NOE)-derived distance restraints, rHFoB monomers form the histone fold and assemble into symmetric (rHFoB)2 dimers that have a structure consistent with assembly into archaeal nucleosomes. rHFoB exhibits approximately 78% sequence homology with rHMfB from the hyperthermophile Methanothermus fervidus, and the results obtained demonstrate that these two proteins have very similar 3D structures, with a root-mean-square deviation for backbone atoms of 0.65 +/- 0.13 A2. (rHFoB)2 dimers however unfold at lower temperatures and require a higher salt environment for stability than (rHMfB)2 dimers, and comparing the structures, we predict that these differences result from unfavorable surface-located ionic interactions and a larger, more solvent-accessible cavity adjacent to residue G36 in the hydrophobic core of (rHFoB)2.

Amino Acid Sequence↗
PubMed1998

PRAK, a novel protein kinase regulated by the p38 MAP kinase.

We have identified and cloned a novel serine/ threonine kinase, p38-regulated/activated protein kinase (PRAK). PRAK is a 471 amino acid protein with 20-30% sequence identity to the known MAP kinase-regulated protein kinases RSK1/2/3, MNK1/2 and MAPKAP-K2/3. PRAK was found to be expressed in all human tissues and cell lines examined. In HeLa cells, PRAK was activated in response to cellular stress and proinflammatory cytokines. PRAK activity was regulated by p38alpha and p38beta both in vitro and in vivo and Thr182 was shown to be the regulatory phosphorylation site. Activated PRAK in turn phosphorylated small heat shock protein 27 (HSP27) at the physiologically relevant sites. An in-gel kinase assay demonstrated that PRAK is a major stress-activated kinase that can phosphorylate small heat shock protein, suggesting a potential role for PRAK in mediating stress-induced HSP27 phosphorylation in vivo.

Amino Acid Sequence↗