PubMed Health⌕ Search

Biomedical subjects

T Wei

Publications and source records attributed to T Wei.

At least 19 recordsLinked to original sources
PubMed2006

Pns4 of rice dwarf virus is a phosphoprotein, is localized around the viroplasm matrix, and forms minitubules.

Rice dwarf virus (RDV), a member of the family Reoviridae, has a 12-segmented dsRNA genome. Seven segments, designated S1, S2, S3, S5, S7, S8, and S9, encode structural proteins, while the remainder encode nonstructural proteins. One of the nonstructural proteins, Pns4, which is encoded by S4, was characterized. Pns4 was a phosphorylatable substrate in a phosphorylation assay in vivo; it associated with large cytoplasmic fibrils and formed novel minitubules in infected cultured cells of its leafhopper insect vector, as revealed by immunofluorescence and immunoelectron microscopy. Early in infection, Pns4 was detected at the periphery of the viroplasm, and it was then observed on amorphous or fibrillar inclusions, which were identified as bundles of minitubules, at later stages of infection. Since viroplasms are believed to be the site of RDV replication, the intracellular location of Pns4 suggests that this protein might be involved in the process of assembly of the RDV virion.

Animals↗
PubMed2006

Value of B-type natriuretic peptide in diagnosing left ventricular dysfunction in dialysis-dependent patients.

BACKGROUND: B-type natriuretic peptide (BNP) is elevated in patients with end-stage renal failure. The reported accuracy of BNP in diagnosing left ventricular dysfunction in these patients has been inconsistent. AIM: To investigate the diagnostic values of BNP for left ventricular dysfunction in patients undergoing haemodialysis for chronic renal failure. METHODS: We measured plasma BNP before and at 10 min and 3, 6 and 24 h after haemodialysis in 56 patients. RESULTS: The average plasma BNP before haemodialysis was 284 +/- 369 pg/mL, which was higher than that of healthy subjects (37 +/- 37 pg/mL; n = 32, P < 0.01). The average plasma BNP in patients with left ventricular dysfunction (n = 21) was substantially higher than that in those with normal ventricular function before and at 10 min and 3, 6 and 24 h after haemodialysis (P < 0.001). The area under the receiver operating characteristic curves was greater than 0.895 before and at the four time points after haemodialysis (P < 0.01). Using 152 pg/mL as a cut-off value, predialysis BNP has 81% sensitivity and 83% specificity in diagnosing left ventricular dysfunction in these patients. CONCLUSION: We concluded that plasma BNP offers a good sensitivity and specificity in diagnosing left ventricular dysfunction in patients with dialysis-dependent renal failure.

Adolescent↗
PubMed2005

Preparation and characterization of silica supported Au-Pd model catalysts.

Au-Pd bimetallic model catalysts were synthesized as alloy clusters on SiO2 ultrathin films under ultrahigh vacuum (UHV) conditions. The surface composition and morphology were characterized with low energy ion scattering spectroscopy (LEIS), infrared reflection absorption spectroscopy (IRAS), and temperature programmed desorption (TPD). Relative to the bulk, the surface of the clusters is enriched in Au. With CO as a probe, IRAS and TPD were used to identify isolated Pd sites at the surface of the supported Au-Pd clusters. Ethylene adsorption and dehydrogenation show a clear structure-reactivity correlation with respect to the structure/composition of these Au-Pd model catalysts.

Journal Article↗
PubMed2005

The composition and structure of Pd-Au surfaces.

Pd, Au, and Pd-Au mixtures were deposited via physical vapor deposition onto a Mo(110) substrate, and the surface concentration and morphology of the Pd-Au mixtures were determined by low-energy ion scattering spectroscopy (LEISS), infrared absorption spectroscopy (IRAS), temperature-programmed desorption (TPD), and X-ray photoelectron spectroscopy (XPS). Pd-Au mixtures form a stable alloy between 700 and 1000 K with substantial enrichment in Au compared to the bulk composition. Annealing a 1:1 Pd-Au mixture at 800 K leads to the formation of a surface alloy with a composition Au(0.8)Pd(0.2) where Pd is predominantly surrounded by Au. The surface concentration of this isolated Pd site can be systematically controlled by altering the bulk Pd-Au alloy concentration.

Journal Article↗
PubMed2005

B-type natriuretic peptide in patients with clinical hyperthyroidism.

AIMS: To investigate the level and clinical significance of plasma B-type natriuretic peptide (BNP) in patients with hyperthyroidism. METHODS: Plasma BNP was measured in 32 healthy subjects and 67 patients with clinical hyperthyroidism. Left ventricular anatomy and function was assessed with echocardiography. RESULTS: The average BNP in hyperthyroid patients was higher than that in healthy subjects (186+/-140 vs 34+/-17 ng/l, p =0.001). The increase in BNP was mainly found in hyperthyroid patients who had clinical and echocardiographic evidence of left ventricular dysfunction (250+/-190 ng/l). The BNP level in patients with hyperthyroidism, but with normal left ventricular function, was similar to that of the controls (37+/-17 vs 34+/-17, ng/l, p>0.05). Multi-regression analysis showed that left atrial diameter and left ventricular ejection fraction were independently associated with the plasma levels of BNP. CONCLUSIONS: there is a significant elevation in plasma BNP in patients with hyperthyroidism; the increase is largely due to hyperthyroidism-induced left ventricular dysfunction. Measurements of plasma BNP may help to detect heart failure in patients with clinical hyperthyroidism.

Adult↗
PubMed2005

Systolic and diastolic heart failure are associated with different plasma levels of B-type natriuretic peptide.

Previous studies have found that plasma B-type natriuretic peptide (BNP) is elevated during left ventricular systolic or diastolic dysfunction. It is unclear whether the ventricular systolic and diastolic function is associated with different levels of plasma BNP. Plasma BNP was measured in 149 heart failure patients by a rapid point-of-care assay. The patients were divided into left ventricular diastolic dysfunction (n = 48), left ventricular systolic dysfunction (n = 62) and right ventricular systolic dysfunction group (n = 39). The mean BNP level in the left ventricular diastolic dysfunction, left ventricular systolic dysfunction and right ventricular systolic dysfunction was 115 +/- 80 pg/ml, 516 +/- 445 pg/ml and 345 +/- 184 pg/ml, respectively (p < 0.05). We concluded that ventricular systolic and diastolic dysfunction increases plasma BNP levels to a different extent. Left and right ventricular systolic dysfunction is associated with a higher level of plasma BNP than left ventricular diastolic dysfunction.

Adult↗
PubMed2004

Differential effects of estrogen and raloxifene on messenger RNA and matrix metalloproteinase 2 activity in the rat uterus.

A detailed analysis of the differential effects of estrogen (E) compared to raloxifene (Ral), a selective estrogen receptor modulator (SERM), following estrogen receptor (ER) binding in gynecological tissues was conducted using gene microarrays, Northern blot analysis, and matrix metalloproteinase (MMP) 2 activity studies. We profiled gene expression in the uterus following acute (1 day) and prolonged daily (5 wk) treatment of E and Ral in ovariectomized rats. Estrogen regulated twice as many genes as Ral, largely those associated with catalysis and metabolism, whereas Ral induced genes associated with cell death and negative cell regulation. Follow-up studies confirmed that genes associated with matrix integrity were differentially regulated by Ral and E at various time points in uterine and vaginal tissues. Additional experiments were conducted to determine the levels of MMP2 activity in uterus explants from ovariectomized rats following 2 wk of treatment with E, Ral, or one of two additional SERMs: lasofoxifene, and levormeloxifene. Both E and lasofoxifene stimulated uterine MMP2 activity to a level twofold that of Ral, whereas levormeloxifene elevated MMP2 activity to a level 12-fold that of Ral. These data show that one of the significant differences between E and Ral signaling in the uterus is the regulation of genes and proteins associated with matrix integrity. This may be a potential key difference between the action of SERMs in the uterus of postmenopausal women.

Animals↗
PubMed2004

Induction of glial L-CCR mRNA expression in spinal cord and brain in experimental autoimmune encephalomyelitis.

Chemokines and chemokine receptors are important regulators of leukocyte trafficking and immune response. It is well established that chemokines and their receptors are also expressed in the central nervous system (CNS), where their expression has been associated with various neuroinflammatory diseases, such as multiple sclerosis (MS). One of the most important chemokines involved in MS pathology is CCL2 (previously known as MCP-1). CCL2, released by glial cells, activates the chemokine receptor CCR2, causing the infiltration of blood monocytes in tissues affected by MS. There is evidence, however, that CCL2 also has local effects on CNS cells, including induction or modulation of cytokine release and synthesis of matrix metalloproteinases, that might contribute to CNS pathology. These effects are most likely independent of CCR2, since CCR2 expression in glial cells is rarely observed. We have recently provided evidence for the presence of an alternative CCL2 receptor in glial cells called L-CCR and have investigated the expression of L-CCR mRNA in a murine EAE model. It is shown that L-CCR mRNA is expressed in infiltrating macrophages during EAE, but not in infiltrating T cells. Prominent expression of L-CCR mRNA was detected in astrocytes and microglia already at early time points throughout the brain and spinal cord supporting the hypothesis that L-CCR expression in glial cells is related to CNS inflammation.

Animals↗
PubMed2003

Chemokine receptors on infiltrating leucocytes in inflammatory pathologies of the central nervous system (CNS).

Haematogenous leucocytes enter the central nervous system (CNS) during diverse disorders of varied aetiologies. Understanding the trafficking cues that mediate CNS leucocyte infiltration might promote the development of flexible and selective means to modulate inflammation to achieve clinical benefit. The trafficking machinery of leucocytes has been elucidated during the past decade and consists of cell-surface adhesion molecules, chemoattractant cytokines (chemokines) and their receptors. Recent work in our laboratory characterized chemokine receptors found on T lymphocytes and monocytes in brain sections from subjects with one pathological subtype of multiple sclerosis (MS), an immune-mediated inflammatory demyelinating disease. In these tissues, the types 1 and 5 CC chemokine receptors (CCR1 and CCR5) were detected on perivascular monocytic cells whereas only CCR5 was present on parenchymal macrophages. The type 3 CXC chemokine receptor (CXCR3) was present on virtually all CD3-positive T cells. In the current study, we evaluated the expression of these receptors on the infiltrating cells present in cases of other inflammatory CNS disorders including those of dysimmune, infectious, neoplastic, and vascular aetiology. Perivascular and parenchymal monocytic cells expressed CCR1 in all cases and CXCR3 was consistently present on a substantial proportion of CD3+ T cells. The occurrence of CCR5 on parenchymal macrophages was much less uniform across the varied disorders. These data implicate CCR1 in monocyte infiltration of the CNS and are consistent with reports of studies in CCR1-deficient mice. CXCR3 is also likely to play a role in accumulation of T cells in the inflamed CNS. By contrast, our findings suggest that regulation of CCR5 on phagocytic macrophages may be contingent on the lesion environment.

Adolescent↗
PubMed2002

Chemokine expression in the central nervous system of mice with a viral disease resembling multiple sclerosis: roles of CD4+ and CD8+ T cells and viral persistence.

During the first 45 days after intracerebral infection with Theiler's murine encephalomyelitis virus (TMEV), the levels of mRNAs encoding chemokines MCP-1/CCL2, RANTES/CCL5, and IP-10/CXCL10 in the central nervous system (CNS) are closely related to the sites of virus gene expression and tissue inflammation. In the present study, these chemokines were monitored during the latter 135 days of a 6-month course of TMEV-induced disease in susceptible (PLJ) or resistant (C57BL/6) mice that possessed or lacked either CD4+ or CD8+ T cells. These data were additionally correlated to mouse genotype, virus persistence in the CNS, antiviral antibody titers, mortality, and the severity of neurological disease. Surprisingly, the major determinant of chemokine expression was virus persistence: the factors of susceptible or resistant genotype, severity of neuropathology, and presence or absence of regulatory T cells exerted minimal effects. Our observations indicated that chemokine expression in the CNS in this chronic viral disorder was intrinsic to the CNS innate immune response to infection and was not governed by elements of the adaptive immune system.

Animals↗
PubMed2001

P2X7-like receptor activation in astrocytes increases chemokine monocyte chemoattractant protein-1 expression via mitogen-activated protein kinase.

Leukocyte infiltration in the CNS after trauma or inflammation is triggered in part by upregulation of the chemokine, monocyte chemoattractant protein-1 (MCP-1), in astrocytes. However the signals that induce the upregulation of MCP-1 in astrocytes are unknown. We have investigated the roles for ATP P2X7 receptor activation because ATP is an intercellular signaling transmitter that is released in both trauma and inflammation and P2X7 receptors are involved in immune system signaling. Astrocytes in primary cell culture and acutely isolated from the hippocampus were immunopositive for P2X7 receptors. In astrocyte cultures, application of the selective P2X7 agonist, benzoyl-benzoyl ATP (Bz-ATP), activated MAP kinases extracellular signal receptor-activated kinase 1 (ERK1), ERK2, and p38. Purinergic antagonists depressed this activation with a profile suggesting P2X7 receptors. Bz-ATP also increased MCP-1 expression in cultured astrocytes, and again P2X7 antagonists prevented this increase. Blocking either the ERK1/ERK2 or the p38 pathway (with PD98059 or SB203580, respectively) significantly inhibited Bz-ATP-induced MCP-1 expression. Coapplication of both antagonists caused a greater depression. We also tested the roles for ATP receptor activation in inducing MCP-1 upregulation in corticectomy, an in vivo model of trauma. This model of cortical trauma was previously shown to increase MCP-1 expression in vivo principally in astrocytes. Suramin, a wide-spectrum purinergic receptor antagonist, significantly depressed the rapid (3 hr) trauma-induced increase in MCP-1 mRNA. These data indicate that purinergic transmitter receptors in astrocytes are important in regulating chemokine synthesis. The regulation of MCP-1 in astrocytes by ATP may be important in mediating communication with hematopoietic inflammatory cells.

Adenosine Triphosphate↗
PubMed2001

Temporal lobe volume determined by magnetic resonance imaging in schizotypal personality disorder and schizophrenia.

The volumes of the whole temporal lobe, the superior temporal gyrus and the corpus callosum were measured on magnetic resonance images from 13 patients with schizotypal personality disorder (SPD), 27 patients with schizophrenia, and 31 age- and sex-matched controls. Temporal lobe structures were traced on consecutive 1.2mm thick SPGR images. Both patient groups had smaller temporal lobes than normal volunteers, a difference that was more marked for the area outside the superior temporal gyrus than for the STG. Correcting for brain volume diminished differences between normal subjects and schizophrenia patients, but the differences between normal subjects and SPD patients remained. Normal volunteers and SPD patients showed significant correlations between the sagittal section area of the posterior portion of the corpus callosum, which carries temporal interhemispheric connections, and the white matter volume of the temporal lobe. While the sample size is modest, taken together, these results suggest that the psychopathological symptoms of SPD may be related to temporal gray matter loss with relatively intact white matter connectivity, while the cognitive and psychotic symptoms of schizophrenia may be related to temporal gray loss combined with disruption of normal patterns of white matter development.

Adult↗
PubMed2001

Monocyte chemoattractant protein (MCP)-1 is rapidly expressed by sympathetic ganglion neurons following axonal injury.

EDI-immunoreactive macrophages, absent from the superior cervical ganglia (SCG) of normal rats, appear in these ganglia within 48h after postganglionic axotomy. Further, resident macrophages show changes after axotomy. Since chemokines function as chemoattractants and activators of leukocytes, the effects of axotomy on chemokine expression in the SCG were examined. Within 6 h after nerve transection, increases were seen in mRNA levels for monocyte chemoattractant protein (MCP)-1. MCP-1 mRNA was concentrated in a population of neurons, while MCP-1 protein was localized to endothelial cells. This axotomy-induced neuronal MCP-1 expression may trigger the infiltration and/or activation of macrophages in SCG after injury.

Animals↗
PubMed2001

Tears contain the complement regulator CD59 as well as decay-accelerating factor (DAF).

Previous studies have shown that DAF (or CD55), a cell surface inhibitor of autologous C3 activation, is present in tears and that > 90% of the C3 convertase regulatory activity in tear fluid resides in this protein (Lass JH et al., Invest Ophth Vis Sci 1990; 31:1136-48). This study investigated whether (i) the membrane cofactor protein (MCP or CD46), an additional factor that regulates C3 activation, and (ii) the membrane inhibitor of reactive lysis (MIRL or CD59), a cell surface regulator that acts to prevent formation of the membrane attack complex, are also present in tears, and if so, are functional. Two-site immunoradiometric assays showed that MCP is present in tears at low levels (42 + 8 ng/ml, n = 8) while CD59 is present at levels (222 + 78 ng/ml, n = 14) comparable to those of DAF (325 + 289 ng/ml, n = 12). The concentrations of CD59 (i) were increased two-fold or more in closed eye tears, and (ii) were decreased in reflex tears. Western blotting showed that CD59 protein in tears migrates with an apparent mol. wt similar to membrane CD59 protein. Phenyl-Sepharose adsorption and Triton X-114 partitioning of tear CD59 as well as of tear DAF however, showed that both proteins are devoid of GPI anchors. Assays using cobra venom factor-activated human serum and guinea pig erythrocytes showed that CD59 is functionally active in inhibiting autologous C5b-9-mediated lysis and, under constitutive conditions, accounts for > 85% of the C9 inhibitory activity in tear fluid.

CD55 Antigens↗
PubMed2001

Regulation of monocyte chemoattractant protein (MCP)-1 transcription by interferon-gamma (IFN-gamma) in human astrocytoma cells: postinduction refractory state of the gene, governed by its upstream elements.

Monocyte chemoattractant protein (MCP)-1 is expressed by astrocytes in diverse inflammatory states and is a key regulator of monocyte recruitment to the central nervous system (CNS). In the current study, we addressed mechanisms by which transcription of the human MCP-1 gene (hMCP-1) was terminated, after induction by interferon (IFN)-gamma. Our results demonstrated that IFN-gamma-induced transcription of hMCP-1 was followed by a refractory state, during which hMCP-1 was resistant to restimulation by either IFN-gamma or heterologous activators such as TNF-alpha. This refractory state affected the hMCP-1 gene selectively, as other IFN-gamma-inducible genes remained responsive to restimulation. The IFN-gamma-induced hMCP-1 refractory state was governed at the transcriptional level and was sensitive to protein synthesis inhibitors, suggesting a requirement for newly expressed components. A minimal 213 base pair hMCP-1 regulatory element directed both IFN-gamma-mediated transcription and the subsequent refractory state. We previously demonstrated that IFN-gamma treatment resulted in coordinate protein occupancy in vivo of two hMCP-1 promoter elements, a gamma-activated site (GAS) and a GC-rich element. During the refractory state, IFN-gamma treatment failed to induce protection of either the hMCP-1 GAS element or the GC box. These results furnish insight into the expression of hMCP-1 during CNS inflammation and provide the first delineation of an IFN-gamma-induced transcriptional refractory state.

Astrocytoma↗
PubMed2001

[Relationship between water supply and consumption of main planting tree species of protection forests in loess area of western Shanxi Province].

Based on three years point-fixed observation, this paper analyzed the relationship between water supply and consumption of black locust(Robinia pseudoscacia L.) and Chinese pine(Pinus tabulaeformis Carr.), the main tree species of protection forests in the loess area of the western Shanxi Province. In April, May and June, the water supply was less than water consumption, while in raining season, the water supply was abundant, and the water storage in soil was increased. During dry seasons and years, more water consumption and less available water supply occurred in high-density stand, showing a serious water deficiency. The water deficiency was in order of south-facing slope > semi-south-facing slope > north-facing slope. The study shows that water consumption characters coefficient could be used as an index to indicate the growth pattern of trees, and the relationship between water supply and consumption.

Trees↗