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C Y Li

Publications and source records attributed to C Y Li.

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

Protection against oxidized low-density lipoprotein-induced vascular endothelial cell death by integrin-linked kinase.

BACKGROUND: Integrin-linked kinase (ILK) is a protein that plays important roles in extracellular matrix-mediated signaling. It has been shown that ILK is expressed preferentially in cardiac and skeletal muscles. Evidence points to its role as an upstream regulator of protein kinase B, a critical player in apoptosis. Because oxidized LDL (oxLDL) is thought to promote atherogenesis by causing the apoptosis of endothelial cells, we investigated the potential roles that ILK may play in oxLDL-induced apoptosis in vascular endothelial cells. METHODS AND RESULTS: Transcriptional and translational levels of ILK were investigated with reverse-transcriptase polymerase chain reaction and Western analysis. oxLDL treatment induced both the transcription and the translation of the ILK gene in endothelial cells. A recombinant adenovirus vector encoding the ILK gene was constructed to investigate its potential role in oxLDL-induced apoptosis in human umbilical vein endothelial cells and mouse lymphoid vein endothelial cells transformed by simian virus 40. In both types of cells, overexpression of the ILK gene significantly prevented oxLDL-induced apoptosis or cell death, as evaluated by 2 independent assay methods. Furthermore, we showed that ILK could inhibit oxLDL-induced upregulation of the kinase activity of p38 mitogen-activated protein kinase, which is often associated with stress-induced pro-apoptotic signal transduction. Finally, examination of other factors, such as bcl-2, bcl-xl, caspase 3, and caspase 9, demonstrated significant changes that were correlated with oxLDL treatment and ILK overexpression. CONCLUSIONS: ILK may be an important factor involved in the regulation of oxLDL-induced apoptosis in vascular endothelial cells. Modifying its activity may be a useful approach for prevention of endothelial cell injury in oxLDL-induced atherosclerosis.

Animals↗
PubMed2001

Accuracy of clinical criteria for AD in the Honolulu-Asia Aging Study, a population-based study.

OBJECTIVE: To determine diagnostic accuracy for AD in a population-based study of Japanese-American men. AD is neuropathologically confirmed for more than 80% of cases at major referral centers (primarily Caucasians); however, information on diagnostic accuracy in population-based studies and studies of different ethnic groups is limited. METHODS: There were 3,734 men who participated in the Honolulu-Asia Aging Study 1991 through 1993 dementia examination and 2,603 in the 1994 through 1996 examination. Diagnoses were based on published criteria. Neuropathologists blinded to clinical data quantified neurofibrillary tangles (NFT) and neuritic plaques (NP). RESULTS: Of 220 autopsied subjects, clinical evaluation revealed 68 with normal cognition, 73 intermediate, and 79 with dementia: 20 AD, 27 vascular dementia, 19 AD + other, and 13 other dementia. Among 20 cases with pure AD, the median value for maximum neocortical NFT density was 6.9/mm(2) and for neocortical NP density was 8.0/mm2. Corresponding densities for other groups were <3.0/mm2. Using established neuropathologic criteria, 25% (5/20) of clinical AD cases had enough NP to meet definite AD criteria, whereas 65% (13/20) had sufficient NP to meet neuropathologic definite or probable AD criteria. Among nine AD cases with moderately severe dementia, only two (22%) had NP densities great enough to meet definite neuropathologic criteria, whereas seven (78%) met neuropathologic criteria for probable AD. CONCLUSIONS: Neuropathologic confirmation and NP density among decedents with clinical AD in this population-based study were lower than reported by referral centers and similar to reports from two other community studies. Ethnic differences in propensity for amyloid deposition as well as differences in clinical severity and representativeness of cases might contribute to these findings.

Aged↗
PubMed2001

Inhibitory effect of endothelin-1 on the isoproterenol-induced chloride current in human cardiac myocytes.

It is still controversial whether the cAMP-activated Cl(-) current (I(Cl,cAMP)) is expressed in human cardiomyocytes. The whole-cell configuration of the voltage-clamp technique was used to examine in detail the I(Cl,cAMP) in single human atrial and ventricular myocytes. Human cardiomyocytes were enzymatically isolated from atrial or ventricular specimens obtained from open-heart surgery or cardiac transplantation, respectively. Isoproterenol (1 microM) or forskolin (10 microM) was used to activate the cAMP second-messenger system. The isoproterenol- or forskolin-induced Cl(-) current was elicited in 12 of 54 atrial myocytes but was completely absent from ventricular myocytes. The isoproterenol-induced Cl(-) current in atrial myocytes was time-independent and had a reversal potential close to zero. Endothelin-1 (30 nM) inhibited the isoproterenol-induced Cl(-) current by 75+/-6% (n=4). This inhibitory effect of endothelin-1 was attenuated by pretreating atrial myocytes with the endothelin ET(A) receptor antagonist, BQ485, but not with the ET(B) receptor antagonist, BQ-788. The results provide evidence that the I(Cl,cAMP) exists in human atria, but not ventricle, and is inhibited by endothelin-1.

Adrenergic beta-Agonists↗
PubMed2001

Acquired pure red cell aplasia associated with lymphoproliferative disease of granular T lymphocytes.

Acquired pure red cell aplasia (PRCA) can be associated with lymphoproliferative disease of granular T lymphocytes (T-LDGL), also known as T-cell large granular lymphocyte leukemia. Fifteen adult patients with PRCA associated with T-LDGL comprise this study. Neutropenia and rheumatoid arthritis were uncommon. All patients responded to immunosuppressive therapy. The 2 most commonly used treatments were prednisone and cyclophosphamide +/- corticosteroids, producing overall response rates of 50% and 60%, respectively. Treatment with cyclophosphamide was associated with a more durable remission (median, 60 versus 7.5 months). After a median follow-up of 67 months, 2 patients died of treatment-related complications, one from myelodysplasia and another from cyclosporine-induced renal failure. The clinical course and treatment responses of PRCA associated with T-LDGL in this series were similar to the general group of PRCA. Because T-LDGL is frequently underdiagnosed, it is likely that a significant proportion of idiopathic or primary PRCA is in fact secondary to T-LDGL.

Adrenal Cortex Hormones↗
PubMed2001

Rubbing-induced molecular reorientation on an alignment surface of an aromatic polyimide containing cyanobiphenyl side chains.

Surface lamellar decoration (SLD), surface enhanced Raman scattering (SERS) and optical second harmonic generation (SHG) experiments have been utilized to study the molecular orientation and conformation changes at a rubbed polyimide alignment-layer surface. This aromatic polyimide containing pendent cyanobiphenyl mesogens was synthesized via a polycondensation of 2,2'-bis(3,4-dicarboxy-phenyl)hexafluoropropane dianhydride (6FDA) with bis[omega-[4-(4-cyanophenyl)phenoxy]hexyl] 4,4'-diamino-2,2'-biphenyldicarboxylate (nCBBP, n = 6), abbreviated as 6FDA--6CBBP. Uniform alignment layers, possessing high pretilt angles ranging from 39 degrees to 43 degrees, have been achieved after mechanical rubbing of the polyimide thin film surface at room temperature and subsequent annealing. This is the first time that high pretilt angles have been detected to possess a negative angle (-theta(c)) with respect to the rubbing direction (i.e., opposite to the rubbing direction), considerably different from the conventional pretilt angle (theta(c)) observed along the rubbing direction. This observation is confirmed using magnetic null and SHG methods. Combined polyethylene (PE) SLD and atomic force microscopy experiments reveal that the azimuthal orientation distribution of the long axis of the edge-on PE lamellar crystals is oriented normal to the rubbing direction, indicating that the PE chains are aligned parallel to the rubbing direction. This SLD technique probes the anisotropic surface orientation of the outermost molecules of the rubbed polyimide layer. The SERS results show that prior to rubbing the surface, both the pendent cyanobiphenyls in the side chains and backbones possess nearly planar chain conformations at the polyimide surface. Mechanical rubbing causes not only tilting of the backbone moieties, such as imide-phenylene structure, but also significant conformational rearrangements of the pendent side chains at the surfaces. The molecular mechanism of this unusual alignment is due to the fact that the pendent cyanobiphenyls forms a uniformly tilted conformation on the rubbed surface, and the polar cyano groups point down toward the layer surface deduced from SHG phase measurements. This conformational rearrangement of the side chains results in the formation of fold-like bent structures on the surface, which directly leads to the long axis of cyanobiphenyls having the -theta(c) pretilt angle with respect to the rubbing direction.

Journal Article↗
PubMed2001

Molecular population genetic analysis of Campylobacter jejuni HS:19 associated with Guillain-Barré syndrome and gastroenteritis.

Infection with Campylobacter jejuni serotype HS:19 is associated with the development of Guillain-Barré syndrome (GBS). To determine whether a particular HS:19 clone is associated with GBS, multilocus enzyme electrophoresis (MLEE) was used to analyze a worldwide collection of isolates. There were 34 electropherotypes (ETs) in 3 phylogenetic clusters among 83 C. jejuni isolates. Cluster I contained all HS:19 strains, and a single ET (ET4) accounted for most HS:19 strains. HS:19 strains did not occur in any of the other clusters. ET4 contained isolates from different geographic locations, indicating global spread of this clone. Furthermore, ET4 contained isolates from patients with uncomplicated enteritis and GBS, as well as isolates from animal sources. The results of this study show that HS:19 strains comprise a clonal, although not monomorphic, population, which is distinct from non-HS:19 strains within C. jejuni. A unique clone associated with GBS was not identified by use of MLEE.

Campylobacter Infections↗
PubMed2001

Clinical correlates of splenic histopathology and splenic karyotype in myelofibrosis with myeloid metaplasia.

Splenic extramedullary hematopoiesis is an integral component of myelofibrosis with myeloid metaplasia (MMM) and may be classified into 3 distinct histologic patterns of infiltration by myeloid precursors: diffuse, nodular, and a predominance of immature granulocytes. These 3 histologic patterns occurred in 121 (56.8%), 75 (35.2%), and 17 (8%), respectively, of 213 patients with MMM who underwent splenectomy at a single institution. In general, karyotypic findings in splenic tissue (n = 92) were similar to those seen in the bone marrow. The histologic pattern of immature granulocyte predominance, the presence of microscopic splenic infarcts (26 patients), or the detection of an abnormal splenic karyotype (52 patients) was significantly associated with decreased postsplenectomy survival. These adverse features were also associated with characteristics of advanced disease. These observations support the bone marrow origin of the myeloid progenitor pool in the spleen of patients with MMM and suggest a prognostic value for splenic histopathology and karyotype. (Blood. 2001;97:3665-3667)

Bone Marrow Cells↗
PubMed2001

Effective tumor therapy with plasmid-encoded cytokines combined with in vivo electroporation.

Plasmids may have unique advantages as a gene delivery system. However, a major obstacle is the low in vivo transduction efficiency. In this study, an electroporation-based gene transduction approach was taken to study the effect of interleukin (IL)-2 or IL-12 gene transduction on the growth of experimental murine tumors. Significant intratumoral gene transduction was achieved by electroporation of tumors that had been injected with naked plasmids encoding reporter genes and cytokine genes (IL-2 and IL-12) under the control of a constitutive cytomegalovirus promoter. In addition, significant tumor growth delay could be achieved in a murine melanoma line B16.F10 with the cytokine genes. Most importantly, systemic transgene levels were negligible when compared with intratumoral adenovirus-mediated IL-12 gene delivery, which leads to significantly higher systemic cytokine levels. Therefore, naked plasmid- and in vivo electroporation-mediated cancer gene therapy may be therapeutically efficacious while maintaining low systemic toxicity.

Adenoviridae↗
PubMed2001

Essential role of the mitochondrial apoptosis-inducing factor in programmed cell death.

Programmed cell death is a fundamental requirement for embryogenesis, organ metamorphosis and tissue homeostasis. In mammals, release of mitochondrial cytochrome c leads to the cytosolic assembly of the apoptosome-a caspase activation complex involving Apaf1 and caspase-9 that induces hallmarks of apoptosis. There are, however, mitochondrially regulated cell death pathways that are independent of Apaf1/caspase-9. We have previously cloned a molecule associated with programmed cell death called apoptosis-inducing factor (AIF). Like cytochrome c, AIF is localized to mitochondria and released in response to death stimuli. Here we show that genetic inactivation of AIF renders embryonic stem cells resistant to cell death after serum deprivation. Moreover, AIF is essential for programmed cell death during cavitation of embryoid bodies-the very first wave of cell death indispensable for mouse morphogenesis. AIF-dependent cell death displays structural features of apoptosis, and can be genetically uncoupled from Apaf1 and caspase-9 expression. Our data provide genetic evidence for a caspase-independent pathway of programmed cell death that controls early morphogenesis.

Animals↗
PubMed2001

Persistent genetic instability in cancer cells induced by non-DNA-damaging stress exposures.

A hallmark of cancer cells is their pronounced genetic instability, which has been implicated in both tumor development and negative treatment outcomes. Recently, it has been reported that ionizing radiation may induce a persistent state of hypermutability in mammalian cells that lasts for many (>30) cell divisions. In this study, we examined whether other stress signals (both DNA-damaging non-DNA-damaging) can initiate a similar process. We show that persistent genetic instability was induced by nongenotoxic stress exposures such as heat treatment, serum starvation, or the tumor microenvironment, as well as genotoxic stresses such as ionizing radiation and exposure to hydrogen peroxide. Progeny of 10-20% of surviving cells exhibited persistent and pronounced genetic instability at both an artificially transfected gene and a genomic minisatellite locus 23 cell divisions after the initial exposure. Stress-induced persistent genetic instability may be a general response of tumor cells to a wide range of genotoxic or nongenotoxic stress conditions.

Animals↗
PubMed2001

Generation of recombinant adeno-associated virus vectors by a complete adenovirus-mediated approach.

An efficient approach to the large-scale production of rAAV will significantly facilitate the application of this promising gene delivery vector in human gene therapy applications. In this study, we report a novel approach to rAAV production that is based exclusively on the adenovirus vector, without the need for plasmid transfections and special packaging cell lines. All components required for rAAV production, including the rep and cap genes, and the therapeutic gene(s) are delivered to the widely used 293 packaging cell line by adenovirus vectors. High-titer rAAV vectors (200-600 infectious units/producer cell) were obtained by use of this approach. As adenovirus vectors can be produced to high titers and they can infect cells in suspension efficiently, this approach may be amenable to scaled-up production of rAAV vectors.

Adenoviridae↗
PubMed2001

Beneficial effect of HCL-31D in murine models of endotoxaemia.

We evaluated the effect of HCL-31D, a novel cAMP-specific phosphodiesterase inhibitor, on the induction of inducible nitric oxide synthase (iNOS) in lipopolysaccharide (LPS) and interferon-gamma (IFN-gamma)-treated rat aortic smooth muscle cells (RASMC) and on survival in a murine model of severe endotoxaemia. Treatment of cultured RASMC with LPS and IFN-gamma resulted in an increase of nitrite, tumour necrosis factor (TNF-alpha) production and induction of iNOS mRNA. However, incubation with HCL-31D (1 approximately 50 microM) for 24 h caused significant attenuation of nitrite and TNF-alpha formation as well as iNOS mRNA induction in a dose-dependent manner but no effect on iNOS activity in RASMC. In addition, administration of HCL-31D (5 mg/kg, i.p.) resulted in that the increase of both plasma nitrate and TNF-alpha levels induced by LPS in vivo was significantly reduced in LPS-treated rats. Treatment of conscious mice with a high dose of LPS (60 mg/kg, i.p.) to ICR mice resulted in a 24-h survival rate of only 10%. However, administration of HCL-31D (5 mg/kg, i.p. at 0 h and 6 h after LPS) improved the 24-h survival to 50%, indicating that HCL-31D has a beneficial effect in murine model endotoxaemia. These effects may be mainly due to inhibition of TNF-alpha formation and of the induction of iNOS. We proposed that the elevation of cAMP levels by HCL-31D may be involved in the prevention of TNF-alpha formation and iNOS induction.

Animals↗
PubMed2001

Diagnosis of mastocytosis: value of cytochemistry and immunohistochemistry.

The diagnosis of mastocytosis or mast cell disease may be difficult sometimes because of the wide variety of clinical presentation, abnormal morphology of mast cells, and variation in histologic features which may mimic varieties of other diseases. Over the years, several cell type specific cytochemical and immunochemical markers have been used for the identification of hematopoietic cells in order to establish the accurate diagnosis of mastocytosis and their associated hematologic diseases. Cytochemical stain for aminocaproate esterase is the most specific enzyme marker for identification of mast cells on cytologic specimens and the immunohistochemical stain for tryptase and/or c-kit has also been established as a sensitive and specific marker for mast cells in paraffin sections.

Acid Phosphatase↗
PubMed2001

Diagnostic criteria and classification of mastocytosis: a consensus proposal.

The term 'mastocytosis' denotes a heterogeneous group of disorders characterized by abnormal growth and accumulation of mast cells (MC) in one or more organ systems. Over the last 20 years, there has been an evolution in accepted classification systems for this disease. In light of such developments and novel useful markers, it seems appropriate now to re-evaluate and update the classification of mastocytosis. Here, we propose criteria to delineate categories of mastocytosis together with an updated consensus classification system. In this proposal, the diagnosis cutaneous mastocytosis (CM) is based on typical clinical and histological skin lesions and absence of definitive signs (criteria) of systemic involvement. Most patients with CM are children and present with maculopapular cutaneous mastocytosis (=urticaria pigmentosa, UP). Other less frequent forms of CM are diffuse cutaneous mastocytosis (DCM) and mastocytoma of skin. Systemic mastocytosis (SM) is commonly seen in adults and defined by multifocal histological lesions in the bone marrow (affected almost invariably) or other extracutaneous organs (major criteria) together with cytological and biochemical signs (minor criteria) of systemic disease (SM-criteria). SM is further divided into the following categories: indolent systemic mastocytosis (ISM), SM with an associated clonal hematologic non-mast cell lineage disease (AHNMD), aggressive systemic mastocytosis (ASM), and mast cell leukemia (MCL). Patients with ISM usually have maculopapular skin lesions and a good prognosis. In the group with associated hematologic disease, the AHNMD should be classified according to FAB/WHO criteria. ASM is characterized by impaired organ-function due to infiltration of the bone marrow, liver, spleen, GI-tract, or skeletal system, by pathologic MC. MCL is a 'high-grade' leukemic disease defined by increased numbers of MC in bone marrow smears (>or=20%) and peripheral blood, absence of skin lesions, multiorgan failure, and a short survival. In typical cases, circulating MC amount to >or=10% of leukocytes (classical form of MCL). Mast cell sarcoma is a unifocal tumor that consists of atypical MC and shows a destructive growth without (primary) systemic involvement. This high-grade malignant MC disease has to be distinguished from a localized benign mastocytoma in either extracutaneous organs (=extracutaneous mastocytoma) or skin. Depending on the clinical course of mastocytosis and development of an AHNMD, patients can shift from one category of MC disease into another. In all categories, mediator-related symptoms may occur and may represent a serious clinical problem. All categories of mastocytosis should be distinctively separated from reactive MC hyperplasia, MC activation syndromes, and a more or less pronounced increase in MC in myelogenous malignancies other than mastocytosis. Criteria proposed in this article should be helpful in this regard.

Adult↗
PubMed2001

New constituents and antiplatelet aggregation and anti-HIV principles of Artemisia capillaris.

Five new constituents including a flavonoid, artemisidin A (1), and four coumarins, artemicapins A (2), B (3), C (4) and D (5), together with 70 known compounds (6-75), have been isolated and characterized from the aerial part of Artemisia capillaris. The structures of these compounds were determined from spectral analyses and/or chemical evidence. Among them, 15 compounds (3, 6, 10, 18. 30-32, 38-41, 44, 45, 51, and 55) showed antiplatelet aggregation activity and three compounds (10, 17, and 51) demonstrated significant activity against HIV replication in H9 lymphocytic cells.

Acetylene↗