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Biomedical subjects

B Han

Publications and source records attributed to B Han.

At least 37 records · Page 2Linked to original sources
PubMed2001

Proliferative capacity of single isolated CD34+ hematopoietic stem/progenitor cells in paroxysmal nocturnal hemoglobinuria.

Paroxysmal nocturnal hemoglobinuria (PNH) results from somatic mutations of the X-linked PIG-A (phosphatidylinositol glycan-class A) gene, which occurs on a hematopoietic stem cell level, leading to a proportion of blood cells being deficient in all glycosylphosphatidylinositol (GPI)-anchored surface proteins. Although these GPI-deficient cells can explain many of the clinical symptoms of PNH, the pathogenesis of PNH is still somewhat obscure and many questions remain. To assess the hematopoietic defect involved in PNH, CD34+ CD59+ (normal phenotype hematopoietic stem/progenitor) and CD34+ CD59- (PNH phenotype) cells from PNH patients (n = 16) and CD34+ CD59+ cells from healthy volunteers (n = 10) were sorted as single cells into 96-well flat-bottom culture plates containing culture medium supplemented with stem cell factor, interleukin (IL)-3, erythropoietin, granulocyte-macrophage-colony-stimulating factor (GM-CSF), G-CSF, IL-6, thrombopoietin, and Flt-3 ligand. We found that the single PNH CD34+ CD59- cells had a growth advantage over the single CD34+ CD59+ cells to some extent, but they both had impaired growth abilities compared with CD34+ cells from healthy volunteers.

Adolescent↗
PubMed2001

Effects of oil sands effluent on cattail and clover: photosynthesis and the level of stress proteins.

The oil sands industry located in northeastern Alberta, Canada, generates large volumes of effluent characterized by a high level of dissolved ions and naphthenic acids. The dikes used to store the effluent seep, creating wetlands which are subsequently invaded by obligate wetland flora such as cattail (Typha latifolia L.). The appearance of these wetlands prompted the oil sands industry to consider wetlands as part of their reclamation strategy. However, to ensure long-term viability of such wetlands, the response of the flora to the industrial effluent needed to be determined. To this end, apparent photosynthesis (APS), the level of ribulose-1,5-bisphosphate carboxylase (RuBisCo) large subunit, dehydrin-related polypeptides, and protein disulphide isomerase (PDI) were evaluated in cattail and alsike clover plants (Trifolium hybridum L.) exposed to the oil sands effluent. APS measured in plants impacted by oil sands effluent was significantly higher than that of plants in the non-impacted off-site location. Among the on-site locations, plants growing in the natural wetlands site had higher APS compared to all other sites. The level of RuBisCo was not increased in cattail or clover growing in effluent-contaminated sites indicating that enhanced photosynthesis was not due to greater levels of this enzyme. Dehydrin-related polypeptides were detected only in the roots of cattail and were absent in clover. The polypeptide profile was altered in cattail exposed to oil sands effluent indicating that they were responding to an osmotic stress. The level of PDI was unaffected in the leaves of cattail regardless of the nature of the effluent to which they were exposed. Overall, the data indicate that cattail and clover are adapted to the oil sands effluent, although further studies are needed to assess their long-term ability to survive in the presence of this anthropogenic stress.

Adaptation, Physiological↗
PubMed2001

Dentinogenesis imperfecta 1 with or without progressive hearing loss is associated with distinct mutations in DSPP.

Dentinogenesis imperfecta 1 (DGI1, MIM 125490) is an autosomal dominant dental disease characterized by abnormal dentin production and mineralization. The DGI1 locus was recently refined to a 2-Mb interval on 4q21 (ref. 1). Here we study three Chinese families carrying DGI1. We find that the affected individuals of two families also presented with progressive sensorineural high-frequency hearing loss (gene DFNA39). We identified three disease-specific mutations within the dentin sialophosphoprotein gene (DSPP) in these three families. We detected a G-->A transition at the donor-splicing site of intron 3 in one family without DFNA39, a mutation predicted to result in the skipping of exon 3. In two other families affected with both DGI1 and DFNA39, however, we identified two independent nucleotide transversions in exons 2 and 3 of DSPP, respectively, that cause missense mutations of two adjacent amino-acid residues in the predicted transmembrane region of the protein. Moreover, transcripts of DSPP previously reported to be expressed specifically in teeth are also detected in the inner ear of mice. We have thus demonstrated for the first time that distinct mutations in DSPP are responsible for the clinical manifestations of DGI1 with or without DFNA39.

Asian People↗
PubMed2001

Family caregiving in hospice: effects on psychological and health functioning among spousal caregivers of hospice patients with lung cancer or dementia.

INTRODUCTION: Caregiving stress has been found to lead to depression and poor health among caregivers compared with age-matched non-caregiving controls. However, most of these studies have focused on dementia caregivers, and have not included hospice caregivers. The aim of this project was to assess the impact of caregiving stress on psychological and health functioning among spousal caregivers of hospice patients, in contrast to demographically matched non-caregiving controls. A secondary aim was to compare the caregiving stressors and psychological and health functioning between spousal caregivers of hospice patients with dementia versus lung cancer. METHODS: Forty spousal caregivers of hospice patients with dementia, and 40 spousal caregivers of hospice patients with lung cancer, were compared on admission to hospice, using measures of caregiving stressors, depression, life satisfaction, and physical health, with a sample of 40 demographically equated control subjects. RESULTS: Both groups of caregivers showed higher depression, lower life satisfaction and poorer physical health (p < .05) compared with non-caregivers. Over half of all caregivers evidenced clinically significant levels of depression, with rates of depression about three times the prevalence found in community samples of older adults. CONCLUSIONS: While family caregivers of hospice patients with dementia and lung cancer face very different objective stressors, the negative psychological and health impacts on the caregiver are marked and comparable across diagnosis. Hospice family caregivers are at high risk for both psychological and physical health disorders, and caregiver depression and health problems should be systematically assessed and treated by the hospice team.

Aged↗
PubMed2001

Phenotypic differentiation of TGF-beta1-responsive pluripotent premesenchymal prehematopoietic progenitor (P4 stem) cells from murine bone marrow.

On the horizon of modern molecular medicine is the requisite technology to capture multipotent human stem cells that are capable of self-renewal and to direct these stem cells along defined lineages for therapeutic purposes. In this article, we describe the hematopoietic and mesenchymal differentiation potential of a unique population of transforming growth factor-beta1 (TGF-beta1)-responsive stem cells derived from murine bone marrow. Stringent selection of the stem cells was accomplished under low serum conditions by virtue of an inherent survival response to a TGF-beta1-vWF fusion protein that was bound to collagen matrices. The TGF-beta1-responsive stem cells initially exhibited a non-adherent and uniformly blastoid morphology, underwent expansion into colonies upon serum reconstitution, and were capable of overt cytodifferentiation along fibrogenic, osteogenic, chondrogenic, or adipogenic lineages upon growth factor stimulation. Remarkably, these stem cells also underwent rapid expansion in the presence of either hematopoietic stem cell factor (SCF) or interleukin3 (IL-3), and differentiated into myeloid and lymphoid phenotypes upon exposure to the latter. Taken together, these results support the hypothesis that pluripotent premesenchymal prehematopoietic progenitor cells, designated P4 stem cells, are present postnatally in murine bone marrow and, thus, may be summarily isolated for various cell-based experimental therapies.

Adipocytes↗
PubMed2001

Jet-impingement heat transfer in gas turbine systems.

A review of jet-impingement heat transfer in gas turbine systems is presented. Characteristics of the different flow regions for submerged jets--free jet, stagnation flow, and wall jet--are reviewed. Heat transfer characteristics of both single and multiple jets are discussed with consideration of the effects of important parameters relevant to gas turbine systems including curvature of surfaces, crossflow, angle of impact, and rotation.

Journal Article↗
PubMed2001

Disruption of gamma-glutamyl leukotrienase results in disruption of leukotriene D(4) synthesis in vivo and attenuation of the acute inflammatory response.

To study the function of gamma-glutamyl leukotrienase (GGL), a newly identified member of the gamma-glutamyl transpeptidase (GGT) family, we generated null mutations in GGL (GGL(tm1)) and in both GGL and GGT (GGL(tm1)-GGT(tm1)) by a serial targeting strategy using embryonic stem cells. Mice homozygous for GGL(tm1) show no obvious phenotypic changes. Mice deficient in both GGT and GGL have a phenotype similar to the GGT-deficient mice, but approximately 70% of these mice die before 4 weeks of age, at least 2 months earlier than mice deficient only in GGT. These double-mutant mice are unable to cleave leukotriene C(4) (LTC(4)) to LTD(4), indicating that this conversion is completely dependent on the two enzymes, and in some organs (spleen and uterus) deletion of GGL alone abolished more than 90% of this activity. In an experimental model of peritonitis, GGL alone is responsible for the generation of peritoneal LTD(4). Further, during the development of peritonitis, GGL-deficient mice show an attenuation in neutrophil recruitment but not of plasma protein influx. These findings demonstrate an important role for GGL in the inflammatory response and suggest that LTC(4) and LTD(4) have distinctly different functions in the inflammatory process.

Animals↗
PubMed2001

CCK independently activates intracellular trypsinogen and NF-kappaB in rat pancreatic acinar cells.

In the cholecystokinin (CCK) hyperstimulation model of acute pancreatitis, two early intracellular events, activation of trypsinogen and activation of nuclear factor-kappaB (NF-kappaB), are thought to be important in the development of the disease. In this study, the relationship between these two events was investigated. NF-kappaB activity was monitored by using a DNA binding assay and mob-1 chemokine gene expression. Intracellular trypsin activity was measured by using a fluorogenic substrate. Protease inhibitors including FUT-175, Pefabloc, and E-64d prevented CCK stimulation of intracellular trypsinogen and NF-kappaB activation. Likewise, the NF-kappaB inhibitors pyrrolidine dithiocarbamate and N-acetyl-L-cysteine inhibited CCK stimulation of NF-kappaB and intracellular trypsinogen activation. These results suggested a possible codependency of these two events. However, CCK stimulated NF-kappaB activation in Chinese hamster ovary-CCK(A) cells, which do not express trypsinogen, indicating that trypsin is not necessary for CCK activation of NF-kappaB. Furthermore, adenovirus-mediated expression in acinar cells of active p65 subunits to stimulate NF-kappaB, or of inhibitory kappaB-alpha molecules to inhibit NF-kappaB, did not affect either basal or CCK-mediated trypsinogen activation. Thus trypsinogen and NF-kappaB activation are independent events stimulated by CCK.

Acetylcysteine↗
PubMed2001

The impact of age, gender, and race on the relationship between depression and self-rated health in community-dwelling older adults: a longitudinal study.

OBJECTIVE: To examine whether the prediction of baseline depression for subsequent changes in self-rated health is consistent across different age cohorts, gender, and racial groups. DATA SOURCES AND STUDY SETTING: A total of 6,714 participants who were 65 years old or older and took part in both the first and the second wave of Assets and Health Dynamics among the Oldest-Old (AHEAD) national survey of community-dwelling older adults were examined. STUDY DESIGN: A two-year prospective cohort study. PRINCIPLE FINDINGS: Baseline depression was an independent risk factor, which not only decreased the odds of having substantial improvement in self-rated health but also increased the possibility of having substantial decline in self-rated health in older men and women, and in Blacks and Whites of all age groups. CONCLUSIONS: Early prevention and treatment of depression among community-dwelling older adults may not only reduce their health decline but also promote their health.

Activities of Daily Living↗
PubMed2001

The structure of self-rated health among community-dwelling older adults with stroke.

OBJECTIVE: To examine whether depressive symptomatology is a third fundamental component of the structure of self-rated health, in addition to two other components (physical disease and functional disability) among community-dwelling older adults with stroke. DATA SOURCES AND STUDY SETTING: A total of 591 community-dwelling older adults with stroke were identified from the 1993 Asset and Health Dynamics among the Oldest-Old (AHEAD) national survey of community-dwelling older adults. STUDY DESIGN: A cross-sectional study. Structural equation modeling was applied to compare a widely used two-factor model of self-rated health with a model adding depression as a third possible factor. PRINCIPLE FINDINGS: The hypothesized three-factor model explained additional 21% more variance of self-rated health of older adults with stroke (R2 = 79%, NNFI = 0.95, CFI = 0.96, RMSEA = 0.04) as compared with the two-factor biomedical model (R2 = 58%, NNFI = 0.95, CFI = 0.98, RMSEA = 0.05). The three-factor model was statistically different from the two-factor model. CONCLUSIONS: Greater attention should be given to the theoretical structure of self-rated health of older adults with stroke, particularly, the significant impact of depression on their self-rated health.

Activities of Daily Living↗
PubMed2001

Hand-transmitted vibration and biodynamic response of the human hand-arm: a critical review.

Hand-arm vibration syndrome (HAVS) has been associated with prolonged exposure to vibration transmitted to the human hand-arm system from hand-held power tools, vibrating machines, or hand-held vibrating workpieces. The biodynamic response of the human hand and arm to hand transmitted vibration (HTV) forms an essential basis for effective evaluations of exposures, vibration-attenuation mechanisms, and potential injury mechanisms. The biodynamic response to HTV and its relationship to HAVS are critically reviewed and discussed to highlight the advances and the need for further research. In view of its strong dependence on the nature of HTV and the lack of general agreement on the characteristics of HTV, the reported studies are first reviewed to enhance an understanding of HTV and related issues. The characteristics of HTV and relevant unresolved issues are discussed on the basis of measured data, proposed standards, and measurement methods, while the need for further developments in measurement systems is emphasized. The studies on biodynamic response and their findings are grouped into four categories based on the methodology used and the objective. These include studies on (1) through-the-hand-arm response, expressed in terms of vibration transmissibility; (2) to-the-hand response, expressed in terms of the force-motion relationship of the hand-arm system; (3) to-the-hand biodynamic response function, expressed in terms of vibration energy absorption; and (4) computer modeling of the biodynamic response characteristics.

Arm↗
PubMed2001

Effects of insulin and antioxidant on plasma 8-hydroxyguanine and tissue 8-hydroxydeoxyguanosine in streptozotocin-induced diabetic rats.

Cumulating evidence suggests that enhanced oxidative stress may contribute to diabetic angiopathy. The levels of 8-hydroxydeoxyguanosine (8-OHdG) and 8-hydroxyguanine (8-OHG), indicators of oxidative DNA damage, in tissue or body fluid are increased in diabetic patients. However, it is unclear whether plasma 8-OHG correlates with tissue 8-OHdG and whether insulin or antioxidant treatment reduces plasma 8-OHG in diabetic state. In this study, we measured the 8-OHG levels in plasma as well as the 8-OHdG levels in liver and kidney in streptozotocin-induced diabetic rats (DR) treated with insulin (DR+I), insulin and probucol (DR+I/P), or insulin and vitamin E (DR+I/E). There was a correlation between plasma 8-OHG levels and tissue 8-OHdG levels (plasma 8-OHG vs. liver 8-OHdG: r = 0.64, P < 0.001; plasma 8-OHG vs. kidney 8-OHdG: r = 0.38, P = 0.06). DR had levels of plasma 8-OHG that were three times higher than control rats (CR), whereas they had levels of tissue 8-OHdG that were approximately 1.5-2 times higher. Plasma 8-OHG levels in DR were almost normalized by insulin treatment, although insulin partially corrected hyperglycemia (plasma 8-OHG: CR 3.3 +/- 2.7 pmol/ml; DR 10.4 +/- 2.3 pmol/ml, P < 0.05 vs. CR; DR with insulin 3.6 +/- 1.0 pmol/ml, P < 0.05 vs. DR). However, tissue 8-OHdG levels in DR were significantly decreased by combined treatment with insulin and antioxidant (probucol or vitamin E), but not by insulin treatment alone. This data suggests that plasma 8-OHG could be a useful biomarker of oxidative DNA damage in diabetic subjects. The mechanism of differential response of plasma 8-OHG and tissue 8-OHdG to insulin and antioxidant treatment remains to be elucidated.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed2001

Inhibition of tumor necrosis factor-alpha (TNF-alpha) production and arthritis in the rat by GW3333, a dual inhibitor of TNF-alpha-converting enzyme and matrix metalloproteinases.

Tumor necrosis factor-alpha (TNF)-converting enzyme (TACE) cleaves the precursor form of TNF, allowing the mature form to be secreted into the extracellular space. GW3333, a dual inhibitor of TACE and matrix metalloproteinases (MMPs), was compared with an anti-TNF antibody to evaluate the importance of soluble TNF and MMPs in rat models of arthritis. Oral administration of GW3333 completely blocked increases in plasma TNF after LPS for up to 12 h. In a model wherein intrapleural zymosan injection causes an increase in TNF in the pleural cavity, GW3333 completely inhibited the increase in TNF in the pleural cavity for 12 h. Under these dosing conditions, the plasma levels of unbound GW3333 were at least 50-fold above the IC(50) values for inhibition of individual MMPs in vitro. In a model wherein bacterial peptidoglycan polysaccharide polymers reactivate a local arthritis response in the ankle, a neutralizing anti-TNF antibody completely blocked the ankle swelling over the 3-day reactivation period. GW3333 administered b.i.d. over the same period also inhibited ankle swelling, with the highest dose of 80 mg/kg being slightly less active than the anti-TNF antibody. In a 21-day adjuvant arthritis model, the anti-TNF antibody did not inhibit the ankle swelling or the joint destruction, as assessed by histology or radiology. GW3333, however, showed inhibition of both ankle swelling and joint destruction. In conclusion, GW3333 is the first inhibitor with sufficient duration of action to chronically inhibit TACE and MMPs in the rat. The efficacy of GW3333 suggests that dual inhibitors of TACE and matrix metalloproteinases may prove therapeutic as antiarthritics.

ADAM Proteins↗
PubMed2001

[Production of transgenic lamb integrated with modified human anti-trypsin gene].

This experiment is to produce the human mAAT(modified anti-trypsin) which cures the emphysema specifically through mammalian galactophore of transgenic goat. 56 goats were selected as donor for superovulation by FSF + LH microinjection in this experiment. The pronucleic embryos were injected with human mAAT gene after fertilization in vivo, and transferred to the donors or receptors directly. The superovulation was better in March and May than in December with the number of ovulation of 19.50, 21.70 and 16.06, and number of fertilized embryos of 4.31, 6.48 and 3.57 per-animal respectively. The pregnant rates were 18.18% and 25% respectively after transferred to donors and receptors with natural estrus. The donors also can be used as the embryo receptor with no remarkable decrease of pregnant rate. 29 lamb were labored. 4 positive transgenic lamb were checked by PCR, PCR-Southern and Southern analysis. The integrated efficiency of foreign DNA was 13.79% with microinjection of high copy number of foreign DNA fragment.

Animals↗
PubMed2001

[Relationship between growth potential of pine, population density of Monochamus alternatus and pathogenicity of Bursaphlenchus xyloophilus].

The results showed that the growth potential of pine (x) is negative related to the population density of Monochamus alternatus (y) and the pathoyenecity of Bursaphlenchus xyloophilus (z). But the population density of Monochamus alternatus is positively related to the pathogenicity of Bursaphlenchus xyloophilus. Three linear equations regression line were established as y = 1793.771 - 16404.47x, z = 31.80989 - 241.9274x, y = -407.611 + 70.51478z. Correlation coefficient is -0.8139, -0.8770 and +0.9864 respectively.

Animals↗
PubMed2001

[Construction of a subtracted cDNA library of differentially expressed genes in human normal liver tissue and primary hepatocellular carcinoma tissue].

OBJECTIVE: To construct a subtracted cDNA library of differentially expressed genes in human normal liver tissue and primary hepatocellular carcinoma (HCC) tissue. METHODS: Using the suppression subtractive hybridization (SSH), a novel technique has been described recently. cDNA fragments of missing or low expressing tumor suppressor genes in HCC tissue were isolated using paracancerous normal liver tissue and HCC tissue as targets. Then these cDNA fragments were directly inserted into T/A cloning vector to set up the subtractive library. Amplification of the library was carried out with transformation of E.coli by high voltage electroperforation. One hundred positive bacteria clones were randomly picked and identified using enzyme restriction method. RESULTS: The amplified library contained more than 4,000 positive bacteria clones. Random analysis of 100 clones with enzyme restriction method showed that all clones contained 200-600 bp inserts. CONCLUSIONS: A subtracted cDNA library of differentially expressed genes in human normal liver tissue and HCC tissue is constructed successfully with SSH and T/A cloning techniques. The library is efficient and lays solid foundation for screening and cloning new and specific missing or low expressing tumor suppressor genes of HCC.

Carcinoma, Hepatocellular↗
PubMed2000

Effect of CO(2) and CHF(3) on the Solubilization of Protein in Reverse Micelles.

The effect of dissolved CO(2) and CHF(3) on the precipitation of bovine serum albumin (BSA) from reverse micelles of sodium bis(2-ethylhexyl) sulfosuccinate (AOT) in 2,2,4-trimethylpentane (iso-octane) has been studied at 308.15 K. It was found that BSA can be precipitated completely by CO(2) while the AOT and water remain in the iso-octane continuous phase. This opens up a possibility for recovery of protein solids directly from reverse micellar solutions. CHF(3) is also an effective agent for precipitation of BSA in the reverse micelles when the expansion coefficient of CHF(3) exceeds 0.4. However, the condition required for complete removal of the BSA using CHF(3) results in some precipitation of AOT and water from the solution. Copyright 2000 Academic Press.

Journal Article↗