Biomedical subjects

L Fu

Publications and source records attributed to L Fu.

At least 37 records · Page 2Linked to original sources

PubMed2001

Fibronectin regulates the activation of THP-1 cells by TGF-beta1.

OBJECTIVE AND DESIGN: To determine how fibronectin regulates the immunomodulatory effects of transforming growth factor (TGF)-beta on THP-1 cells. MATERIAL OR SUBJECTS: THP-1 monocytic cell line. TREATMENT: THP-1 cells were primed for 48 h in the presence or absence of 250 pM TGF-beta1. METHODS: Assays or assessments carried out, together with statistical test applied. RESULTS: We found that adherence to fibronectin dramatically modulates the effects of TGF-beta1 on the human monocytic cell line THP-1. TGF-beta did not significantly affect constitutive interleukin (IL)-8 secretion or IL-1beta-induced IL-8 secretion from suspended cells. In contrast, TGF-beta stimulated IL-8 secretion as well as augmented IL-1beta-induced IL-8 secretion from adherent cells. The differential effects of TGF-beta1 on IL-8 secretion from suspended and adherent cells could not be explained by differences in IL-1 receptor antagonist production. The effects of fibronectin on TGF-beta1 induced IL-8 secretion from THP-1 cells were mimicked by adhesion to immobilized anti-a4beta1 integrin antibody and to a fibronectin fragment containing the CS-1 domain. CONCLUSIONS: These results indicate that alpha4beta1-mediated adhesion to fibronectin may play a key role during inflammation by profoundly influencing the effects of TGF-beta1 on monocytes.

Cell Adhesion↗

PubMed2001

Gene expression of apolipoprotein(a) within the wall of human aorta and carotid arteries.

Atherosclerosis is associated with arterial deposition of low density lipoprotein (LDL) and lipoprotein(a), Lp(a). Both lipoproteins have been detected in atherosclerotic vessels; however, while LDL has been shown to be only blood-derived, it is not clear whether Lp(a) is also produced within the vessel wall. In the present investigation we studied gene expression of apo(a) and apoB in human blood vessels. Aorta, carotid arteries and liver specimens from 29 adult and pediatric autopsy cases were studied by RT-PCR and Southern blot analysis with primers and probes specific for apo(a), apoB and GAPDH (a control housekeeping gene). The mRNA of apo(a), but not apoB, was found within the vessel wall in both adult atherosclerotic arterial vessels and in pediatric non atherosclerotic vessels. Neither apo(a) nor apoB mRNA was detected in femoral veins. To verify the nature of the detected transcripts, we cloned the 162 base pair (bp) RT-PCR product derived from the arterial wall total RNA. Nucleotide sequencing revealed 100% homology with the apo(a) gene. Thus, while LDL in atherosclerotic arteries is exclusively blood-derived, the accumulation of Lp(a) within the artery may be due in part to in situ production of apo(a) within the vessel wall.

Adult↗

PubMed2001

In vitro study of possible role of dietary fiber in lowering postprandial serum glucose.

There have been many reports concerning the role of dietary fiber in lowering postprandial serum glucose, and the main mechanism was regarded as the viscosity of different dietary fibers in hampering diffusion of glucose and postponing absorption and digestion of carbohydrates. In this paper, two kinds of water-insoluble dietary fibers, water-insoluble dietary fiber of wheat bran and enzyme-resistant starch of maize amylose, and four kinds of water-soluble dietary fibers, water-soluble dietary fiber of wheat bran, carboxymethyl cellulose, guar gum, and xanthan gum, were used to investigate their postprandial serum glucose lowering mechanism in vitro. The results showed that these dietary fibers lowered postprandial serum glucose levels at least by three mechanisms. First, dietary fibers increase the viscosity of small intestine juice and hinder diffusion of glucose; second, they bind glucose and decrease the concentration of available glucose in the small intestine; and, third, they retard alpha-amylase action through capsuling starch and the enzyme and might directly inhibit the enzyme. All of these decreased the absorption rate of glucose and the concentration of postprandial serum glucose.

Adsorption↗

PubMed2001

Conformational study of N(epsilon)-(carboxymethyl)lysine adducts of recombinant gammaC-crystallin.

N(epsilon)-(carboxymethyl)lysine, an advanced glycation end product, is present in the human lens. The effects of CML formation on protein conformation and stability were studied using the recombinant gammaC-crystallin as a model. Conformational change was studied by spectroscopic measurements such as fluorescence and circular dichroism. Conformational stability was determined by unfolding with heat. The results indicated that no conformational change was observed due to CML formation, but conformational stability decreased. These observations can be explained in terms of the relatively stable structure of gamma-crystallin, especially when compared with other crystallins. The lens nucleus is rich in gamma-crystallin and its stable conformation can assist gamma-crystallin sustained insults and remain soluble.

Circular Dichroism↗

PubMed2001

TACI-ligand interactions are required for T cell activation and collagen-induced arthritis in mice.

Interactions of the tumor necrosis factor superfamily members B lymphocyte stimulator (BLyS) and a proliferation-inducing ligand (APRIL) with their receptors-transmembrane activator and CAML interactor (TACI) and B cell maturation molecule (BCMA)-on B cells play an important role in the humoral immune response. Whereas BCMA is restricted to B cells, TACI is also expressed on activated T cells; we show here that TACI-Fc blocks the activation of T cells in vitro and inhibits antigen-specific T cell activation and priming in vivo. In a mouse model for rheumatoid arthritis (RA), an autoimmune disease that involves both B and T cell components, TACI-Fc treatment substantially inhibited inflammation, bone and cartilage destruction and disease development. Thus, BLyS and/or APRIL are important not only for B cell function but for T cell-mediated immune responses. Inhibition of these ligands might have therapeutic benefits for autoimmune diseases, such as RA, that involve both B and T cells.

Animals↗

PubMed2001

Thyroid hormone regulation of apoptotic tissue remodeling during anuran metamorphosis.

Anuran metamorphosis involves systematic transformations of individual organs in a thyroid hormone (TH)-dependent manner. Morphological and cellular studies have shown that the removal of larval organs/tissues such the tail and the tadpole intestinal epithelium is through programmed cell death or apoptosis. Recent molecular investigations suggest that TH regulates metamorphosis by regulating target gene expression through thyroid hormone receptors (TRs), which are DNA-binding transcription factors. Cloning and characterization of TH response genes show that diverse groups of early response genes are induced by TH. The products of these TH response genes are believed to directly or indirectly affect the expression and/or functions of cell death genes, which are conserved at both sequence and function levels in different animal species. A major challenge for future research lies at determining the signaling pathways leading to the activation of apoptotic processes and whether different death genes are involved in the regulation of apoptosis in different tissues/organs to effect tissue-specific transformations.

Animals↗

PubMed2001

Assessment of vehicular pollution in China.

As the motor vehicle population in China continues to increase at an annual rate of approximately 15%, air pollution related to vehicular emissions has become the focus of attention, especially in large cities. There is an urgent need to identify the severity of this pollution in China. Based on an investigation into vehicle service characteristics, this study used a series of driving cycle tests of in-use Chinese motor vehicles for their emission factors in laboratories, which indicated that CO and HC emission factors are 5-10 times higher, and NOx 2-5 times higher, than levels in developed countries. The MOBILE5 model was adapted to the Chinese situation and used to calculate the emission of pollutants from motor vehicles. Results show that vehicle emission is concentrated in major cities, such as Beijing, Guangzhou, Shanghai, and Tianjin. Motor vehicle emissions contribute a significant proportion of pollutants in those cities, with contribution rates of CO and NOx greater than 80% and 40%, respectively, in Beijing and Guangzhou. Urban air quality is far worse than the national ambient air quality standard. In conclusion, although China has a relatively small number of motor vehicles, most of them are concentrated within metropolitan areas, and their emissions are closely related to urban air pollution problems in large cities.

Air Pollutants↗

PubMed2001

Sequence analysis of the S gene of recombinant MHV-2/A59 coronaviruses reveals three candidate mutations associated with demyelination and hepatitis.

Coronaviruses, mouse hepatitis virus (MHV) strains, exhibit various degrees of neurotropism and hepatotropism following intracerebral (IC) infection of 4-week-old C57Bl/6 mice. Whereas MHV-A59 produces acute meningitis, encephalitis, hepatitis, and chronic demyelination, a closely related strain, MHV-2, produces only acute meningitis and hepatitis. We previously reported that the spike glycoprotein gene of MHV contains determinants of demyelination and hepatitis. To further investigate the site of demyelination and hepatitis determinants within the S gene, we sequenced the S gene of several nondemyelinating recombinant viruses. We found that three encephalitis-positive, demyelination-negative, hepatitis-negative recombinant viruses have an MHV-A59-derived S gene, which contains three identical point mutations (I375M, L652I, and T1087N). One or more of the sites of these mutations in the MHV-A59 genome are likely to contribute to demyelination and hepatitis.

Amino Acid Substitution↗

PubMed2001

Source contributions to ambient concentrations of CO and NOX in the urban area of Beijing.

An emission inventory based on GIS technology was developed in this study, and used to estimate the spatial distribution of the stationary and mobile sources in the urban area of Beijing. The stationary sources were divided into various types of finer classes depending on different usage, stack height and emission factors. The mobile sources were treated as both line sources and area sources. It was shown that total anthropogenic CO and NOX emissions had reached 1.4 million and 233 thousand tons, respectively, and vehicle sources emissions of CO and NOX accounted for 76.8% and 40.2%, respectively, of the total emissions in 1995. ISCST3, a Gaussian dispersion air quality model, was modified at low wind speed condition, and then used to facilitate the study of source contributions to ambient concentrations of CO and NOX in Beijing. The simulation results showed that emissions from the vehicle sources had contributed 76.5% and 68.4% of the total CO and NOX concentrations in urban atmosphere of Beijing in 1995, and were even higher in the city core (86.3% of the CO and 72.0% of the NOX). Therefore, strategies for CO and NOX pollution control will of necessity need to focus on the vehicle sources.

Air Movements↗

PubMed2001

Extrahepatic expression of apolipoprotein A-II in mouse tissues: possible contribution to mouse senile amyloidosis.

Apolipoprotein A-II (apoA-II), an apolipoprotein in serum high-density lipoprotein, is a precursor of mouse senile amyloid fibrils. The liver has been considered to be the primary site of synthesis. However, we performed nonradioactive in situ hybridization analysis in tissue sections from young and old amyloidogenic (R1.P1-Apoa2C) and amyloid-resistant (SAMR1) mice and revealed that other tissues in addition to the liver synthesize apoA-II. We found a strong hybridization signal in the basal cells of the squamous epithelium and the chief cells of the fundic gland in the stomach, the crypt cells and a small portion of the absorptive epithelial cells in the small intestine, the basal cells of the tongue mucosa, and the basal cells of the epidermis and hair follicles in the skin in both mouse strains. Expression of apoA-II mRNA in those tissues was also examined by RT-PCR analysis. Immunolocalization of apoA-II protein also indicated the cellular localization of apoA-II. ApoA-II transcription was not observed in the heart. Amyloid deposition was observed around the cells expressing apoA-II mRNA in the old R1.P1-Apoa2C mice. These results demonstrate that the apoA-II mRNA is transcribed and translated in various extrahepatic tissues and suggest a possible contribution of apoA-II synthesized in these tissues to amyloid deposition.

Aging↗

PubMed2001

Health status and health-related quality of life in survivors of cancer in childhood in Latin America: a MISPHO feasibility study.

Cancer is an increasing cause of disease-related death in childhood within developing countries, where the great majority of the world's children reside. The improving prospects for survival in such children, and the corresponding challenge of undertaking economic evaluations of related health interventions, provide a stimulus to study the health-status and health-related quality of life in survivors of cancer in childhood in Latin America. Spanish language versions of questionnaires for proxy assessors, based on the Health Utilities Index (HUI), were used to elicit responses from parents and physicians. The HUI is a family of multi-attribute, generic, preference-linked measures of health status and health-related quality of life that are reliable, responsive and valid, and have been used previously in pediatric oncology. Valid responses were received from 178 parents and 144 physicians in 6 centres in 4 countries (Cuba, Honduras, Colombia and Uruguay). For children with acute lymphoblastic leukemia the major morbidity burdens were in the attributes of emotion, cognition and pain. The overall burden of morbidity was greater in children with non-Hodgkin's lymphoma. In survivors of Hodgkin's disease and Wilms' tumor the attributes most affected were emotion and pain. In general, there was considerable agreement between the assessments provided independently by parents and physicians. This study demonstrates the feasibility of conducting such measurements in developing countries, and reveals similarities in health status and health-related quality of life to comparable populations in more privileged societies.

Child↗

PubMed2001

[Effect of PAI-1 antisense RNA on vascular endothelial growth factor expression in aorta smooth muscle cells cultured in vitro].

OBJECTIVE: To investigate the role of plasminogen activator inhibitor-1(PAI-1) antisense RNA in regulating the expression of PAI-1 and vascular endothelial growth factor (VEGF) in aorta smooth muscle cells cultured in vitro. METHODS: The second extron of PAI-1 was amplified with polymerase chain reaction(PCR), the production was inserted into eukaryotic cell expression vector pcDNA3.1 after it had been purified and cloned so as to construct PAI-1 antisense RNA recombination plasmid. The recombination plasmid was transfected into SMC. PAI-1 expression was detected by immunohistochemistry, Western blod and ELISA; the effects of PAI-1 variation on VEGF was examined by immunofluorescence. RESULTS: PAI-1 antigen was the lowest in cells on the third day after transfection; the expression of VEGF was also decreased. PAI-1 antigen gradually increased on the fifth day and VEGF increased correspondingly. On the seventh day, PAI-1 antigen and VEGF increased to nearly normal level. CONCLUSION: PAI-1 antisense RNA can block the translation progress of PAI-1 proteins effectively and inhibit the expression of VEGF in aorta smooth muscle cells.

Aorta↗

PubMed2001

[Expression of human anti-HBsAg-interferon fusion protein in CHO cells].

OBJECTIVE: To study the possibility of expressing human anti-HBsAg-interferon fusion protein in CHO cells as a putative targeting drug for hepatitis B. METHODS: Both the heavy and light chain genes of human anti-HBsAg antibody derived from a phage display library were fused with alpha-2b interferon (IFN-alpha-2b) gene in vitro by polymerase chain reaction. The IFN alpha-2b gene was placed at the C terminal and a 15 amino acid linker was introduced at the fusion site. The light chain-IFN expression plasmid pLIC was constructed with a mammalian expression vector pcDNA3.1(+) and the heavy chain-IFN expression plasmid pFID was constructed with another mammalian expression vector pCdhfr1. These plasmids and the anti-HBsAg full-length light and heavy chain expression plasmids (pLIC and pHFD, respectively) were transfected into CHO (dhfr-) cells by the following three combinations:I, pLIC + pHFD;II, pLIC + pFID; III, pLFC + pFID. The cultured supernatant of the transfected cells was collected and assayed for IFN activity and HBsAg affinity. RESULTS: The supernatant of combination I and II displayed IFN activity but only combination I supernatant exhibited HBsAg affinity. CONCLUSIONS: The successful expression of a fusion protein with both HBsAg affinity and interferon activity may lead to a new way to make a targeting drug for hepatitis B.

Animals↗

PubMed2001

[Analysis on effect of inspection and maintenance (I/M) program for vehicle emission reduction].

An Inspection and maintenance(I/M) programme aims to ensure that motor vehicle emission control systems are functioning properly throughout the two stage idle test. Based on three factors including data from inspection, standard for inspection and failure rate, the effectiveness of the current I/M program was studied through the cumulative distributions. The disadvantages of the cutpoints, institution settings, management, and supervision was also analyzed. The fundamental law of emission limits was proposed.

Carbon Monoxide↗

PubMed2001

[Biodegradation of reactive turquoise blue].

In this study, the anaerobic degradation and the aerobic degradation of a kind of reactive dye--Reactive Turquoise Blue(RTB) were compared. The results proved that anaerobic sludge could only decompose RTB in the presence of glucose while aerobic sludge decomposed RTB with or without the presence of glucose (RTB of 20 mg/L was reduced by 37.4% through 24 hours' aerobic treatment with RTB as sole carbon source). The enhancement of glucose concentration was beneficial for both anaerobic and aerobic degradation of RTB: the anaerobic and the aerobic removal efficiencies were respectively 81.5% and 73.6% with RTB of 20 mg/L and glucose of 1200 mg/L. In the influent RTB concentration also had influence on the activity of anaerobic and aerobic microorganisms. When glucose concentration was 800 mg/L or 1200 mg/L and RTB concentration was 20 mg/L to 100 mg/L, anaerobic removal efficiency of RTB was higher than aerobic removal efficiency by 4.9%-27.2%, which meant that anaerobic bacteria is more powerful than aerobic bacteria in terms of RTB removal.

Aerobiosis↗

PubMed2001

[Motor vehicle source contributions to air pollutants in Beijing].

Beijing's motor vehicle emission inventory based on GIS technology was developed, and used to estimate the contribution rate of different types of vehicles and different areas of vehicles to the total vehicular emissions in the urban area of Beijing. ISCST3, a gaussian dispersion air quality model, was modified at low wind speed condition, and then used to facilitate the study of the spatial and temporal distribution of CO and NOx concentrations in Beijing. It was shown that vehicle source emissions of CO and NOx accounted for 76.8% and 40.2%, respectively, of the total emissions in 1995. The simulation results also showed that emissions from the vehicle sources had contributed 76.5% and 68.4% of the total CO and NOx concentrations in urban atmosphere of Beijing in 1995, and were even higher at down-town and near the arteries. Therefore, strategies for CO and NOx pollution control will of necessity need to focus on the vehicle sources.

Air Pollutants↗

PubMed2001

Relationship between gene polymorphism of the PAI-1 promoter and myocardial infarction.

OBJECTIVE: To investigate the association between gene polymorphism of the plasminogen activator inhibitor-1 (PAI-1) and myocardial infarction (MI) in Chinese. METHODS: PAI-1 genotyping with polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and allele specific polymerase chain reaction (ASPCR) was performed in 87 myocardial infarction patients and 92 unrelated healthy controls. All subjects' clinical features and PAI-1 activity were tested. RESULTS: There were two polymorphisms within the promoter, a G/A single base substitution polymorphism upstream at -844 bp, and a single guanosine deletion/insertion 4G/5G polymorphism -675 bp upstream from the start of transcription. Significant differences between the patients and the controls were observed neither for the frequencies of the GG, GA and AA genotypes nor for the PAI-1 activities of these three types. But for the 4G/5G polymorphism, there were significant differences between patients and controls for the frequencies of the 4G/4G, 4G/5G and 5G/5G genotypes (P < 0.05). In the MI group, the PAI-1 activity of the 4G/4G type was significantly higher than that of the 5G/5G type (P < 0.05). Further more, a positive correlation between the glucose level and PAI-1 activity was found (r = 0.34, P = 0.02). CONCLUSION: This study indicates that the 4G/5G gene polymorphism of PAI-1 is associated with myocardial infarction, that 4G/4G type is probably an important hereditary risk factor, and that glucose has functional importance in regulating PAI-1 activity.

Adult↗

PubMed2001

[A clinicopathological study of clear cell sarcoma of the kidney].

OBJECTIVE: To study the clinicopathological, immunohistochemical features and the histogenesis of clear cell sarcoma of the kidney (CCSK). METHODS: CCSK specimens from 45 pediatric cases, including 31 male and 14 female with an age range from 3 months to 12 years (mean of 3.2 years), were retrieved. Routine pathological, immunohistochemical and electron microscopic methods were utilized to analyze the CCSK specimens. RESULTS: 35 of the 45 cases were followed from 6 to 192 months. 15 patients presented with bone metastases, 6 had lung or liver metastases, 8 recurred and 20 died. Age and clinical stage at diagnosis correlated with the rate of survival. Histologically, the classic pattern of CCSK consisted of cells with pale cytoplasm, fine nuclear chromatin and indistinct nucleoli separated by an arborizing fibrovascular stroma. Other patterns were identified, including myxoid, spindle, palisading, epithelioid, sclerosing, cellular, cystic, and angiectatic. All tumors contained multiple patterns. Immunohistochemically, all cases were positive for vimentin, but negative for EMA, CK, desmin, actin, S-100, NSE, CD99, CD34 and LCA. Electron microscopy of 9 cases showed features of primitive cell conjunction and few organelles. CONCLUSION: CCSK is a common renal neoplasm of childhood. CCSK may arise from renal mesenchymal cells and has the propensity to metastasize to the bone with poor clinical outcome.

Child↗