Biomedical subjects

W Hu

Publications and source records attributed to W Hu.

At least 289 records · Page 16Linked to original sources

PubMed1993

[Forum: reconstruction of the traumatic thumb. Reconstruction of the thumb by osteocutaneous flaps of the forearm].

The authors present different techniques of thumb reconstruction using osteocutaneous retrograde island forearm flaps. They describe an original thumb reconstruction technique by using the anterior interosseous osteocutaneous retrograde island flap and present two clinical cases. The advantages and disadvantages as well as the indications of this kind of thumb reconstruction procedure are discussed.

Adult↗

PubMed1993

[Changes in erythrocyte deformability in patients with pregnancy induced hypertension and its significance].

The changes of erythrocyte deformability measured by the laser diffractometer in 25 cases of normal pregnancy and 37 cases of pregnancy induced hypertension (PTH) were studied. The results indicated that the erythrocyte deformability remained relatively stable over the course of normal gestation. There was no difference between controls and mild PIH cases (P > 0.05). However, in the moderate and severe PIH cases a significantly lower erythrocyte deformability (P < 0.01) was demonstrated. The relationship of low erythrocyte deformability with PIH needs further investigation.

Adult↗

PubMed1992

A report of two cases of chronic serious manganese poisoning treated with sodium para-aminosalicylic acid.

Two cases of chronic manganese poisoning were treated with sodium para-aminosalicylic acid (PAS-Na; 6 g/day in 500 ml of 10% glucose solution by intravenous drip). The results indicated that one had been clinically cured and that the other had obviously improved in clinical symptoms and signs. Thus PAS-Na appears to be an effective drug for treatment of serious chronic manganese poisoning.

Aminosalicylic Acid↗

PubMed1992

[Isolation and characterization of prolactin messenger RNA from bovine anterior pituitary glands].

The messenger RNA was extracted from bovine anterior pituitary glands and was purified by oligo(dT)-cellulose chromatography. The length of the mRNA was 1,200 nucleotides measured by agarose gel electrophoresis containing methylmercury hydroxide. The bovine prolactin (PRL) mRNA was confirmed by Northern blot analysis of the mRNA with gamma-32P labelled synthetic oligonucleotide probes based on the partial amino acid sequences of bovine PRL and could stimulate the incorporation of 35S-methionine into protein in the rabbit reticulocyte cell-free system. The translation product of bovine PRL mRNA was immunoprecipitable by rabbit anti-ovine PRL anti-antibodies. The molecular weight of the translation product corresponding to the bovine PRL precursor was estimated to be approximately 25,000 by SDS polyacrylamide gel electrophoresis and autoradiograph.

Amino Acid Sequence↗

PubMed1992

Studies on the epidemiology and etiology of moldy sugarcane poisoning in China.

Moldy sugarcane poisoning, an acute fatal food poisoning of unknown etiology, has occurred in 13 provinces in China. The epidemiological characteristics and clinical features were described. Evidence from laboratory studies indicates that 3-nitropropionic acid produced by the fungus Arthrinium Spp. is the etiological factor of this food poisoning.

Adolescent↗

PubMed1991

Mechanisms of the coronary vascular effects of platelet-activating factor in the rat perfused heart.

1. In a previous study it was demonstrated that bolus injections of platelet-activating factor (PAF) in the rat perfused heart resulted in coronary vasodilatation, vasoconstriction or the combination of both, depending on the amount of PAF that was injected. In the present study, the mechanisms of these coronary vascular effects of PAF in the rat perfused heart were investigated. 2. Pretreatment of the rat perfused heart with the PAF antagonists FR-900452 or BN-52021 did not affect the vasodilator effect of PAF but eliminated the vasoconstrictor effect of PAF. FR-900452 had no effect on the vasoconstrictor response to leukotriene C4 (LTC4) or LTD4. 3. The cyclo-oxygenase inhibitor, indomethacin, did not modify the coronary vascular effects of PAF. However L-649,923 (a leukotriene antagonist) and MK-886 (a leukotriene synthesis inhibitor) eliminated both the vasodilator and vasoconstrictor effects of PAF. 4. When leukotrienes were administered by bolus injection in the rat perfused heart, LTB4 produced vasodilatation while LTC4 and LTD4 produced vasoconstriction. L-649,923 blocked both the vasodilator and vasoconstrictor effects of the leukotrienes tested. 5. The results suggest that lipoxygenase products are responsible for both the vasodilator and vasoconstrictor actions of PAF in the coronary vasculature of the rat perfused heart while the cyclo-oxygenase products do not play a significant role. The ineffectiveness of PAF antagonists in blocking the vasodilatation produced by PAF is compatible with the concept that there may be multiple PAF receptors.

Animals↗

PubMed1991

Simian immunodeficiency virus negative factor suppresses the level of viral mRNA in COS cells.

The nef gene is conserved among all human and simian lentiviruses. However, the amino acid similarity between simian immunodeficiency virus (SIV) and human immunodeficiency virus type 1 NEF is only 38%. To assess the role of SIV NEF on virus replication and compare its activity with that of its human immunodeficiency virus type 1 counterpart, we examined the activity of an intact nef gene from proviral clone pSIV 102, an isolate from SIV-MAC-251-infected cells. Proviral clone pSIV BA was constructed by introducing a premature termination codon at codon 40 of the nef gene without altering the predicted amino acid sequence of the overlapping env gene. These two clones were transfected into CD4- COS cells, and virus replication was monitored by p27 enzyme-linked immunosorbent assay kits. In seven independent experiments, clone pSIV BA afforded two- to sixfold greater levels of viral antigen compared with those in clone pSIV 102 and two- to sixfold-increased levels of viral mRNAs as indicated with Northern (RNA) blot and S1 nuclease protection analyses. Nuclear run-on assays demonstrated a two- to threefold increased rate of RNA synthesis with nuclei isolated from cells transfected with pSIV BA compared with that from cells transfected with pSIV 102. In contrast, there was no apparent destabilization of SIV mRNAs by NEF, as measured in dactinomycin-treated cells. This study demonstrates that SIV NEF is a negative regulator of virus replication and acts by suppressing the level of mRNA synthesis and accumulation in COS cells.

Amino Acid Sequence↗

PubMed1991

Study on multiple-enzyme electrode for sucrose determination.

Invertase (INV), mutarotase (MUT), glucose oxidase (GOD) and BSA were coimmobilized via glutaraldehyde-bridged covalent bonding, and directly absorbed on the teflon membrane. This membrane was covered with a nylon mesh and placed over an oxygen electrode. An enzyme electrode for flow injection analysis system (EFIA) was adopted. The optimum enzyme composition (IU) for immobilization on the teflon membrane of INV-MUT-GOD was found to be in the ratio 72:48:2.4, with a recovery activity INV-MUT of more than 42.9%. pH 5.8-6.5 was the most suitable range of acidity for the sensor activity. The optimum temperature was 35-45 degrees C. The system exhibited good linearity in the range of 5 x 10(-4) approximately 10(-1) M sucrose (kinetic method) and 10(-5) approximately 2 x 10(-3) M sucrose (steady state method), in short response time (20 seconds for kinetic method, 2 minutes for steady state method), CV = 1.7% (kinetic method). The sensor had been used for determining sucrose concentration in fermentation broth, with an average recovery rate of 98%. The interference caused by the presence of glucose derived from decomposition of sucrose was eliminated by calibration with a GOD sensor. No significant loss of the enzyme electrode activity was observed after 120 hours of the continuous flow of fresh 1 mM sucrose. The multiple-enzyme membrane showed a relatively long lifetime (compared with 14 hours as reported previously) and good storage stability (30 days, stored in distilled water at 4 degrees C).

Biosensing Techniques↗

PubMed1990

Differential IgE receptor development on rat tissue cultured mast cells.

Rat tissue cultured mast cells established previously were cloned and subcloned by limiting dilution and analyzed for surface expression of both high- (Fc epsilon RI) and low-affinity (Fc epsilon RL) receptors for IgE. Analysis of receptor development in continuous culture over a period of 24 weeks revealed that Fc epsilon RL expression increased with time in all cases, irrespective of initial receptor density on the cell surface. Expression of Fc epsilon RI as measured in terms of its alpha-chain showed more clonal variation, exhibiting increases, decreases, as well as relative constancy over the time period. These results suggest that the two types of receptors are regulated independently and that some of the rat tissue cultured mast cell clones studied represent different stages of mast cell development.

Animals↗

PubMed1989

Analysis of the function of viral protein X (VPX) of HIV-2.

To investigate the function of vpx, a gene in HIV-2 and SIV, but not in HIV-1, three site-directed mutants (pMX) were constructed from a functional proviral HIV-2 plasmid clone (pSE). Transfection of COS-1 cells with all three mutants as well as pSE gave rise to equivalent amounts of virus. Each virus could be passaged in H9 and CEM lymphoid cell lines, peripheral blood lymphocytes, and monocytes with equal efficiency and demonstrated similar cytopathic effects. Hybridization data with DAN from the infected cells demonstrated the presence of similar levels of viral sequences and the mutations in each of the MX-infected cell lines. Immunoprecipitation analysis demonstrated a 16-kDa VPX protein in cells infected with SE virus, as well as in the virus particles, but not in cells infected with MX viruses or the particles themselves. However, equivalent levels of gag and env proteins were demonstrated in all infected cells and virion preparations. These data suggest that VPX is dispensable for virus replication and cytopathicity.

Amino Acid Sequence↗

PubMed1989

The detection of an antibody against IgA allotype A2M 2 and a study of the Am genetic marker among the Han Chinese population.

The serum of a woman was found by the Ouchterlony double-diffusion and the hemagglutination inhibition (HAI) methods to have immunoglobulin A (IgA) deficiency. Further investigation using the hemagglutination (HA) test with red cells coated with IgA myeloma proteins of different specificities showed that the serum agglutinated only IgA2-, A2M-1, and A2M 2-coated cells. The patterns of the HAI test with a reference panel confirmed the presence of two specificities. One was anti-IgA2 and the other was a rare antibody against the allotype A2M 2. The anti-A2M 2 was used for population studies. Testing of the Han Chinese population, including family studies, confirms that A2M.1 and A2M.2 have an autosomal dominant mode of inheritance and are controlled by a codominant allele. The distribution of the two Am genetic markers among the Han Chinese population demonstrated A2M.1 with a gene frequency of 0.553 and A2M.2 with a gene frequency of 0.447 (chi 2 = 0.145, 0.80 greater than p greater than 0.70).

Alleles↗

PubMed1989

Role of the carboxy-terminal portion of the HIV-1 transmembrane protein in viral transmission and cytopathogenicity.

The transmembrane glycoprotein (gp41) of human immunodeficiency virus type-1 (HIV-1) has a long cytoplasmic domain of unknown functional significance. To investigate the role of the carboxy-terminal (C-terminal) portion of the HIV-1 envelope protein in viral replication, infectivity, and cytopathogenicity, we examined the properties of a panel of mutants with variable deletions in the 3'-env region. Deletion of the C-terminal 76 amino acids did not abolish production of reverse transcriptase upon transfection of COS-1 cells. Deletion of the C-terminal 6-14 amino acids appeared sufficient to alter the replication pattern, infectivity, and cytopathogenicity of some clones. The data suggest that conformational determinants or specific sequences are responsible for the observed changes, rather than simply the length of the gp41 cytoplasmic tail.

Cytopathogenic Effect, Viral↗

PubMed1989

Viral protein R of human immunodeficiency virus types 1 and 2 is dispensable for replication and cytopathogenicity in lymphoid cells.

Viral protein R (VPR) is conserved in human immunodeficiency virus types 1 and 2 (HIV-1 and HIV-2). To assess its function, we have constructed mutations within the vpr coding regions of HIV-1 and HIV-2 predicted to express truncated VPR products. Infectious virus was produced by each proviral clone and showed similar replication kinetics and cytopathogenicity when compared with the corresponding parental proviral clone.

Animals↗

PubMed1988

Topography of basal glucose utilization in rat thalamus and hypothalamus determined with (1-14C)-glucose.

High resolution autoradiography was used to study the basal pattern of glucose-utilization in the rat thalamus and hypothalamus. Rats were injected via chronic jugular catheter with (1-14C)-glucose and sacrificed 30 min later. The high resolution thaw-mount autoradiographic procedure, using 4 micron frozen sections and nuclear emulsion, permitted discrimination of regional variations in glucose-utilization that have not yet been described. Quantitative data were obtained by means of digital image analysis and computerized densitometry. In the thalamus, high activity was present in the anterodorsal, anteroventral, laterodorsal and reticular nuclei, while low activity was found in the mediodorsal and paraventricular nuclei. The autoradiographic pattern of glucose utilization in the thalamus corresponds largely to classical cytoarchitectonic subdivisions. In the hypothalamus, the median eminence, arcuate nucleus, and periventricular nucleus showed the lowest activity, whereas certain parts of the lateral hypothalamus appeared high. Very high activity was present in mammillary nuclei. The described detailed anatomical data of glucose-utilization may provide insights into the functional circuitry of thalamic and hypothalamic systems and serve as a baseline from which experimental manipulations can be assessed.

Animals↗

PubMed1988

Studies on the physical state of water in living cells and model systems. X. The dependence of the equilibrium distribution coefficient of a solute in polarized water on the molecular weights of the solute: experimental confirmation of the "size rule" in model studies.

The equilibrium distribution of 14 sugars, sugar alcohols, and other nonelectrolytes in solutions of polyethylene oxide (PEO) and of native and alkali-denatured bovine hemoglobin were studied over wide concentration ranges. The results show that the equilibrium concentrations of all the solutes studies are rectilinearly related to their external concentrations. This straight-line relationship demonstrates the existence of these solutes entirely or almost entirely in the aqueous phase of these systems. Therefore the slope of each of these straight lines equals the equilibrium distribution coefficient or q-value of the solute involved. In general, the q-values decrease with increasing molecule weights (M.W.) of the solutes in 15% solutions of PEO, 20% solutions of alkali-denatured hemoglobin (and in 18% gelatin) but not in 39% solution of native hemoglobin. In solutions of PEO, of alkali-denatured hemoglobin studied (and of gelatin) a fraction of the water (20% to 30%) appears to have solvency similar to that of normal liquid water. The experimental findings of M.W.-dependent solute exclusion were discussed in the light of four alternative theories that have been offered to explain this type of phenomena. Among these four theories only the polarized multilayer theory agrees with most, if not all the facts known.

Animals↗

PubMed1987

Characterization of adult human marrow hematopoietic progenitors highly enriched by two-color cell sorting with My10 and major histocompatibility class II monoclonal antibodies.

Monoclonal antibodies, My10 (HPCA-1) and major histocompatibility class II (HLA-DR), were used to enrich and phenotype normal human marrow colony-forming unit: granulocyte-macrophage (CFU-GM), burst-forming unit: erythroid (BFU-E), and multipotential colony-forming unit: granulocyte-erythroid-macrophage-megakaryocyte (CFU-GEMM) progenitor cells. Nonadherent low density T lymphocyte-depleted marrow cells were sorted on a Coulter Epics 753 dye laser flow cytometry system with the use of Texas Red-labeled anti-My10 and phycoerythrin conjugated anti-HLA-DR. Cells were separated into populations with nondetectable expression of antigens (DR-My10-) or with constant expression of one antigen and increasing densities of the other antigen. More than 98% of the CFU-GM, BFU-E, and CFU-GEMM were found in fractions containing cells expressing both HLA-DR and My10 antigens. The cloning efficiency (CE) of cells in the DR-My10- cell fraction was 0.01%. In the antigen-positive sorted fractions, the CE was highest (up to 47%) in the fractions of cells expressing high My10 and low DR (My10 DR+) antigens and was lowest (2.5%) in the fraction of cells expressing low My10 and low DR (My10+DR+) antigens. Populations of cells varying in the density of HLA-DR, but not My10, antigens varied in the proportion and types of progenitor cells present. When My10-positive cells were sorted for HLA-DR density expression, the CE for CFU-GM was similar in the DR+ and DR++ fractions, but most of the BFU-E and CFU-GEMM were found in the DR+ fraction. Within the CFU-GM compartment, most of the eosinophil progenitors were found in the DR+ fraction, whereas a greater proportion of macrophage progenitors were detected in the DR++ fraction. CFU-GM and BFU-E in the fractions of cells positive for DR and My10 were assessed for responsiveness to the effects of recombinant human tumor necrosis factor-alpha, recombinant human interferon-gamma, and prostaglandin E1. Colony formation from CFU-GM was suppressed by the three molecules, and colony formation by BFU-E was suppressed by recombinant human tumor necrosis factor-alpha and interferon-gamma and enhanced, in the presence of T lymphocyte-conditioned medium, by prostaglandin E1 in all antigen-positive fractions.(ABSTRACT TRUNCATED AT 400 WORDS)

Alprostadil↗

PubMed1987

c-myc gene inactivation during induced maturation of HL-60 cells. Transcriptional repression and loss of a specific DNAse I hypersensitive site.

The c-myc proto-oncogene is amplified and expressed at high levels in HL-60 cells, a cell line derived from a patient with acute promyelocytic leukemia. Upon induction to terminal maturation, expression of c-myc is greatly reduced. We have studied the level of gene expression at which the change in c-myc expression is controlled and the changes in chromatin configuration that accompany the repression of myc expression. We report here that the repression of myc expression with induced maturation is controlled at the level of transcription, and that reduced expression is accompanied by the loss of a single DNAse I hypersensitive site 0.9 kilobase pair upstream from the gene.

Cell Differentiation↗

PubMed1987

Prostaglandin E acts at two levels to enhance colony formation in vitro by erythroid (BFU-E) progenitor cells.

The prostaglandin E (PGE) enhancement of erythroid colony formation by human bone marrow erythroid progenitor cells (BFU-E) is mediated by a T8+ subset of lymphocytes. Medium was conditioned by bone marrow and blood T-lymphocytes and T-lymphocyte subsets (T8+, T8-, T4+, and T4- cells) in the absence or presence of PGE1 in order to determine if the cells could release a cell-free source of erythroid colony enhancing activity and what the conditions for this release would be. The T-lymphocyte conditioned medium was assayed for its effects on erythroid colony formation by nonadherent low-density T-lymphocyte depleted (NALT-) bone marrow cells plated in the presence of erythropoietin, hemin, phytohemagglutinin-stimulated leukocyte conditioned medium, or medium conditioned by 5637 cells, in the absence or presence of PGE1 and in the presence or absence of serum. PGE1 induced the release of an erythroid colony enhancing activity from the T8+ and T4-, but not from the T8- and T4+ subsets of lymphocytes, but this cell-free source of activity was only apparent if it was tested for colony formation in the presence of added PGE1. The release and action of the PGE1 induced T-lymphocyte erythroid enhancing activity did not require the presence of serum. Erythroid colony formation by NALT- bone marrow cells was not enhanced by PGE1 alone, by medium conditioned by T-lymphocytes in the absence of PGE1, or by PGE1 plus medium conditioned by T-lymphocytes in the absence of PGE1. The results suggest that the PGE1 enhancement of erythroid colony formation occurs by an apparently synergistic action on non-T-lymphocytes by PGE1 itself and by a factor or factors released from T8+ lymphocytes in response to PGE1.

Alprostadil↗