Biomedical subjects

L Wang

Publications and source records attributed to L Wang.

At least 1,369 records · Page 76Linked to original sources

PubMed1998

[Influence of dextran 40 and dextran 70 on the adhesion of erythrocytes to endothelial cells].

Adopting the flow chamber realtime microrecordation system, we studied the dynamic effects of dextran 40(DX40) and dextran 70(DX70) on the adhesion of erythrocytes to monolayer of cultured human umbilical vein endothelial cells (HUVEC). The results demonstrated that erytherocytes pretreated with DX40 adhered to HUVEC less than the erythrocytes of the control group did, but DX70 increased the number of erythrocytes adhering to HUVEC. The higher the concentration of DX70 was, the more the erythrocytes pretreated with DX70 adhered to HUVEC. When shear stress increased, the decrease rate of the number of erythrocytes (pretreated with DX70) adhering to HUVEC declined with the increase of DX70 concentration. These indicate that DX40 as an expander of blood plasma is better than DX70.

Cell Adhesion↗

PubMed1998

[Precollagen III in the vitreous of eyes with proliferative vitreoretinopathy].

PURPOSE: To detect precollagen III (PC III) levels in serum and vitreous samples from patients with proliferative vitreoretinopathy (PVR). METHODS: PC III levels were measured by radioimmunoassay in 5 cadaveric vitreous samples from normal subjects, 20 normal human serum samples, 29 vitreous and serum samples from patients with rhegmatogenous retinal detachment complicated with PVR. The relationship between PC III levels and PVR history, surgery, epiretinal membrane, severity of PVR were analyzed with Logistic regression analysis. RESULTS: The mean PC III levels in serum samples of PVR patients and control subjects were 83.76 +/- 18.52 and 85.02 +/- 17.50 micrograms/L respectively (P > 0.05). PC III was not detected (< 40 micrograms/L) in the cadaveric vitreous. In vitreous aspirates from 29 eyes with PVR, it was not detected in 12 eyes, but higher than 40 micrograms/L in 17 eyes with the mean level of 268.69 +/- 176.07 micrograms/L. (P < 0.05) The high levels correlated with duration and severity of PVR. As onset time and PVR grade increasing, the probability of PC III concentration higher than 40 micrograms/L was 5.2655 and 2.7978 times the concentration lower than 40 micrograms/L respectively. CONCLUSION: PC III can be detected in vitreous aspirates from PVR eyes. The PC III levels in the vitreous was an event of local responses and were correlated with severity and history of PVR. This suggests that PC III and collagen III be involved in the development of PVR.

Adolescent↗

PubMed1998

[The observations of plasma of AC operation in the CT-6B Tokamak by Ha emissions].

The spatial distribution and temporal evolution of plasma of AC operation in the CT-6B Tokamak has been observed through Ha emissions by an optical multichannel diagnostic system for the first time. The results show the plasma density is not completely lost during current reversal, therefore, there were no need for second breakdown after the current reversal. The spatial and temporal evolution of plasma is dependent on the current wave forms.

English Abstract↗

PubMed1998

[Determination of total amount of acid in soda water by AAS].

A new indirect AAS method for the determination of the total amount of acid in soda water is investigated. After adding MgNH4PO4 reagent to sample solution to react with organic acid, the unreacted reagent subsides by using centrifuge and Mg is detected in solution by AAS. The content of acid is calculated in samples. The results agreed weel with those obtained by volumetric analysis. The relative standard deviations are less than 5.3% and the recoveries are between 91 and 104%.

Acids↗

PubMed1998

[Study on a new method for spectrophotometry].

In this paper, the relation between absorbance difference and concentration was measured by the ultraviolet spectrophotometer and computer made P-E company of U.S.A. The basic goal is to prove that the standard absorption curve method can be replaced by the new method, in which the sample was put in standard room and the standard material in sample room. Utilizing this method can minimize the error, most importantly, can measure the higher concentration sample, which can not be measured by the standard curve method. The new method does not require a Linear deltaA-c linear relationship.

English Abstract↗

PubMed1998

[Spectroscopic investigations on sol-gel transition of alginate solutions by addition of cupric ion].

Viscosity measurements and 13C-NMR, UV/VIS, and Raman spectroscopic studies have been carried out of various concentration of alginate solutions undergoing sol-gel transition induced by addition of cupric cation. From analyses of the spectra, a qualitative explaination was suggested of the interaction mode of the coordination between functional groups and cupric ions, the conformational change of polychains and the behaviour of solvent molecules druing the process of sol-gel transition. The mechanisms of phase transition of our system induced by the heavy metal ion have been discussed.

English Abstract↗

PubMed1998

[Direct determination of trace elements in tungsten products with ICP-AES].

A direct determination of Al, As, Ca, Cd, Co, Cr, Cu, Fe, Mg, Mn, Mo, Ni, Sn, Ti and V in tungsten products with ICP-AES is presented. The influence of tungsten matrix is studied. Based on the selected optimum operating parameters, the feasibility of the proposed method is evaluated by analyzing three WO3 National References. The results are satisfactory.

English Abstract↗

PubMed1998

[Determination of Sb in the resin and products of PET by graphite furnace atomic absorption spectrometry].

The method of determing Sb in resin and products of PET by graphite furnace atomic absorption spectrometry was studied. The sample was pretreated by 4% acetic acid and determined by graphite furnace atomic absorption spectrometry. The sensitivity of this method was 30.5 pg/1% absorption, the relative standard deviation was 3.12% and the rate of recovery was 91.68-97.74%. The results obtained by this method agreed with those of malachite green spectrophotometry.

English Abstract↗

PubMed1998

Common fragile sites and cancer (review).

Chromosomal fragile sites are specific loci which are especially susceptible to forming gaps, breaks and rearrangements in metaphase chromosomes when cells are cultured under conditions that inhibit DNA replication. Fragile sites are grouped into two classes the 'rare' and the 'common' fragile sites, based on their frequency of occurrence and means of induction. The common fragile sites are apparently present as a constant feature in all individuals and their clinical significance is that they might predispose chromosomes to breakage and rearrangement during cancer development. The most frequently observed common fragile sites occur, in decreasing order, at 3p14.2 (FRA3B), 16q23 (FRA16D), 6q26 (FRA6E), 7q32 (FRA7H), and Xp22 (FRAXB). FRA3B has been of particular interest since it is the most active common fragile site, and is located in a chromosomal band that is frequently deleted in several solid tumors suggesting that a putative tumor suppressor gene resides there. In this review we describe our work on the characterization of FRA3B and the analysis of deletions in the FRA3B region in several different tumor-derived cell lines. We also describe our efforts to identify other common fragile sites and to determine the role that these sites play in tumor development.

Acid Anhydride Hydrolases↗

PubMed1998

Positive biochemical effects of a bioartificial liver support system (BALSS) in a porcine fulminant hepatic failure (FHF) model.

This study describes biochemical changes in the plasma and blood of pigs with devascularised livers treated in a bioartificial liver support system (BALSS). Porcine hepatic cells were incubated with collagen-coated dextran microspheres (CDM) for 3 hours and the medium tested to determine cellular metabolic activity. Incubation continued for a further 18 hours during which the hepatic cells attach to the CDM. The CDM-attached cells were inoculated into a hollow fibre bioreactor which was part of an extracorporeal support system. Hepatic cell content of the bioreactor was 6 x 10(9) cells. The system was tested in a controlled trial in pigs prepared in a surgical model of fulminant hepatic failure (FHF). When plasma from FHF pigs was circulated through the device containing hepatic cells, there was significantly less increase in the accumulation of ammonia and most amino acids, together with a decrease in plasma lactate and of one amino acid, compared to control experiments when hepatic cells were excluded. We conclude that primary porcine hepatocytes can contribute beneficial metabolic function in a BALSS.

Adenosine Triphosphate↗

PubMed1998

[A comparative study of imaging of myocardial perfusion with 201Tl-SPECT and 13NH3-PET: visual and quantitative evaluation].

UNLABELLED: We compared the results of visual and quantitative evaluation of imaging of myocardial perfusion with 201Tl-SPECT and 13NH3-PET in the 7 non-myocardial infarction (non-MI) and 42 myocardial infarction (MI) patients. On the 201Tl-SPECT and 13NH3-PET imaging, the degree of accumulation of each radioisotope (RI) was visually classified into four grades of defect score. The percentage of uptake was also quantitatively evaluated. RESULTS: In the 7 non-MI patients, NH3% uptake in the lateral wall was significantly lower than in the septum, and in the lateral wall NH3% uptake was significantly lower than Tl% uptake. For the 42 MI patients, segmental defect scores (DS) on 201Tl-SPECT were compared with those on 13NH3-PET, and a high degree of concordance in DS was found for all territories of the left ventricle, antero-septum MI and inferior MI territories. Average Tl% uptake/NH3% uptake was near 1, a highly positive correlation was found between Tl% uptake and NH3% uptake in all territories of the left ventricle and antero-septum MI territories, and Tl% uptake/NH3% uptake was larger than 1, but, a significant positive correlation existed between Tl% uptake and NH3% uptake in the territory with inferior MI. CONCLUSION: These findings indicate that results of 201Tl-SPECT imaging were similar to those of 13NH3-PET in evaluation of myocardial perfusion in the antero-septum and inferior. However, a difference in distribution was observed between 201TlCl and 13NH3 in the lateral wall, indicating that particular attention should be paid to the results of imaging of myocardial perfusion in the lateral wall.

Aged↗

PubMed1998

[Detection of presymptomatic patients and heterozygotes with Wilson's disease by using haplotypes of microsatellites].

OBJECTIVE: To develop a rapid, exact and effective technique of gene diagnosis for the early diagnosis of patients with wilson's disease(WD) and detection of WD heterozygotes. METHODS: Five microsatellite (or short tandem repeat, STR) loci at D13S301, D13S316, D13S296, AFM238vc3 and AFM184xc5 were amplified by polymerase chain reaction(PCR). D13S301 was a locus within WD gene, the others were in the flank of WD gene. After detection of amplified fragment length polymorphism of the five STR loci with denaturing polyacrylamide gel electrophoresis(AFLP-PAGE), the STR haplotypes analyses were performed on 120 members in 23 WD families. RESULTS: The five STR loci had high polymorphism information content(PIC). PICs of D13S301, D13S316, D13S296, AFM084xc5 and AFM238vc3 were 0.89, 0.93, 0.91, 0.91 and 0.94 respectively. The STR haplotypes analyses confirmed that the two patients previously diagnosed doubtfully were WD patients definitely. Among 31 sibs without any clinical symptoms, 4 were diagnosed as presymptomatic patients, 8 as WD heterozygotes, 17 as normal homozygotes and 2 as doubtful presymptomatic patients. CONCLUSION: Haplotypes analysis of the five STR loci can provide high genetic information. It provides a new important technique in gene diagnosis of WD.

Adult↗

PubMed1998

[Investigation of the genetic instability of tumor cells by transfection of RER+ cell lines with exogenous microsatellite sequence].

OBJECTIVE: Frequent alterations of microsatellite sequence of cancer cells were found recently in a substantial fraction of human cancers including hereditary non-polyposis colon cancer. This paper aimed to investigate the genetic instability of tumor cells by using microsatellite instability(MI) as the marker in vitro. METHODS: Two RER+ cell lines (replication error phenotype), RKO and HCT116 and one RER- cell line, sw480, were used as the hosts for transfection with an episomal plasmid, pCMV-CAR, containing an exogenous (CA)14 repeat which was inserted within the coding sequence of lacZ reporter gene and thus made lacZ misreading. The transfectant clones were selected and established by hygromicin. Expression and production of lacZ reporter gene of restored reading frame were detected with X-gal staining assay. RESULTS: After hygromicin selection, stable pCMV-CAR transfectant clones were established. It was shown that mutation of deletion of insertion within(CA)14 occurred in the transfectant RER+ cells but not in the RER-cells. The mutation restored normal reading frame of lacZ gene, and resulted in expression and production of bio-active beta galactosidase which was detected with X-gal staining. This feature of the transfectant clones was maintained during culture passages. CONCLUSION: The alterations of the exogenous(CA)14 repeat in the transfectant RER+ clones revealed genetic instability and complicated mutation status of cancer cells. It is suggested that the exogenous (CA)14 in transfectant clones could be a useful target sequence for monitoring the effects of environmental agents on MI of human cancer cells.

Cell Line↗

PubMed1998

Quantitative nerve fiber layer measurement using scanning laser polarimetry and modulation parameters in the detection of glaucoma.

PURPOSE: To assess a new method of processing quantitative nerve fiber layer (NFL) measurement data to distinguish between eyes with glaucoma of varying severity and normal eyes, using information obtained by scanning laser polarimetry. PATIENTS AND METHODS: Scanning laser polarimetry measurements of the peripapillary NFL within a 10-pixel band located 1.8 disc diameters from and concentric with the disc margin were obtained from 36 normal eyes, 69 eyes with glaucoma, 7 eyes suspected of being glaucomatous, and 19 eyes with ocular hypertension. These values then were examined using new data processing "modulation" parameters in which the average of the nasal and temporal minimum retardation is subtracted from the retardation in the superior or inferior region of the peripapillary NFL. The ability of modulation parameters to differentiate between normal and glaucomatous eyes was compared with other parameters based either on the sum of retardation values in the superior or inferior region, or on the ratio of values in the superior or inferior region to the nasal region. RESULTS: Differences in mean polarimetric retardation between normal eyes and eyes with glaucoma were significant for all parameters, but were greatest when modulation parameters were used and were significantly greater for two modulation parameters. The range of values showed considerable overlap between all groups of eyes. Eyes with ocular hypertension had mean values intermediate between normal eyes and eyes with early glaucomatous damage. CONCLUSION: The use of new modulation parameters increases the ability of quantitative NFL measurement to distinguish between eyes with glaucoma of varying severity and normal eyes.

Adult↗

PubMed1998

The identification and phylogenetic relationship of pathogenic species of Aspergillus based on the mitochondrial cytochrome b gene.

To study the identification and phylogeny of pathogenic isolates of Aspergillus, we designed primers from known cytochrome b amino acid sequences. Using these primers, 426 bp fragments of a mitochondrial (mt) cytochrome b gene were amplified by polymerase chain reaction (PCR), directly sequenced, and compared among Aspergillus fumigatus, A. flavus, A. niger, A. terreus and Emericella nidulans. Except for E. nidulans, all strains produced the 426 bp fragment by PCR. The E. nidulans strains demonstrated both an intron-presence fragment ( approximately 1500 bp) and intron-absence fragment (426 bp). Species-specific nucleotides were found in each of the five species. Based on sequence analysis, the strains were further divided into several groups within each species. When a 142-amino-acid sequence was estimated from the 426 bp nucleotide sequence using the yeast mt genetic code, the amino acid sequences showed no difference among strains of the individual species. DNA-based phylogenetic and amino acid-based trees were constructed. In conclusion, the DNA sequences of the cytochrome b gene may be of use in identification of pathogenic Aspergillus species and the amino acid-based tree suitable for discussing their phylogenetic relationships.

Amino Acid Sequence↗

PubMed1998

Correlation of peripapillary nerve fiber layer thickness by scanning laser polarimetry with visual field defects in patients with glaucoma.

PURPOSE: To assess the correlation between the results of peripapillary scanning laser polarimetry of the retinal nerve fiber layer (NFL) and automated visual field testing in patients with open-angle glaucoma. METHODS: Visual fields from 42 patients with varying stages of glaucoma were scored using Collaborative Initial Glaucoma Treatment Study (CIGTS) criteria. Mean deviation, pattern standard deviation, and CIGTS total and hemifield visual field scores were correlated with peripapillary NFL thickness measured by scanning laser polarimetry using summed, ratio-based, and modulation parameters. RESULTS: Mean deviation and CIGTS total and upper hemifield score were significantly correlated with NFL retardation values using summed, ratio-based, or modulation parameters. The CIGTS lower hemifield score was significantly correlated with modulation parameter values only. Correlation of CIGTS scores was significantly stronger with modulation parameters than with summed parameters (total and lower hemifield scores) and ratio-based parameters (lower hemifield only) by the Hotelling t test. CONCLUSION: Relative NFL thickness measured by scanning laser polarimetry correlates well with visual field defects seen on Humphrey perimetry of patients with open-angle glaucoma. Modulation parameters, in which the superior and inferior peak NFL thickness (as measured by scanning laser polarimetry) are adjusted for the patient's average minimum NFL thickness in the nasal and temporal quadrants, provided stronger correlation than summed parameters and ratio-based parameters.

Adult↗

PubMed1998

Expression of p21WAF1 predicts outcome of esophageal cancer patients treated by surgery alone or by combined therapy modalities.

The p21WAF1 protein is an important regulator of the cell cycle. Its expression and prognostic significance were investigated immunohistochemically in samples of normal esophageal squamous epithelium (n = 10), severe squamous cell dysplasia (n = 20), carcinoma in situ (n = 14), permanent esophageal squamous cell carcinoma cell lines (n = 3), and invasive squamous cell carcinomas treated either by potentially curative resection (n = 172) or by combined modality therapy (radiochemotherapy +/- surgery; n = 38). Whereas p21WAF1 expression in the normal epithelium was restricted to a few cells adjacent to the basal cell layer, p21WAF1 overexpression was frequently found in preneoplasias and invasive carcinomas. Expression of p21WAF1 in invasive carcinomas was not correlated with tumor differentiation, pT category, or pN category. Among carcinomas treated by potential curative resection, univariate (P = 0.0025) and multivariate (P = 0.0081) survival analysis showed significant correlation of strong p21WAF1 expression (> or =50% p21WAF1-positive tumor cells) with poor overall survival. Univariate survival analysis (P = 0.0006) revealed the same prognostic influence in the group of patients treated by combined modality therapy. We conclude that overexpression of p21WAF1 protein is a frequent event in preneoplasias and neoplasias of the esophagus. Immunohistochemical examination of p21WAF1 expression may provide important prognostic information for decision-making in the treatment of patients with esophageal cancer.

Adult↗

PubMed1998

Molecular effects of recombinant human interleukin-11 in the HLA-B27 rat model of inflammatory bowel disease.

Recombinant human interleukin-11 (rhIL-11) is a pleiotropic cytokine with effects on multiple cell types. In addition to thrombopoietic activity, rhIL-11 has demonstrated anti-inflammatory activity in vitro and in vivo. rhIL-11 treatment reduces clinical signs and histologic lesions of colitis in transgenic rats expressing the human major histocompatibility complex (MHC) Class I allele, HLA-B27. We have investigated the effects of rhIL-11 at the molecular and cellular level in this model of inflammatory bowel disease. RT-PCR analysis of colonic RNA revealed that treatment with rhIL-11 down-regulated expression of proinflammatory cytokines including TNF-alpha, IL-1beta, and IFN-gamma. rhIL-11 also reduced the level of myeloperoxidase activity in the cecum indicating reduced inflammation. After stimulation in vitro with anti-CD3 antibody, spleen cell cultures derived from rhIL-11-treated rats produced less IFN-gamma, TNF-alpha, and IL-2 than cultures derived from vehicle-treated rats. These molecular and cellular effects correlated with amelioration of disease as measured by stool character and histologic lesion scores. These findings suggest that rhIL-11 acts to reduce inflammation through modulation of multiple proinflammatory mediators including products of activated T cells. This study has identified pharmacodynamic markers of rhIL-11 anti-inflammatory activity in vivo and supports rhIL-11 therapy to treat inflammatory bowel disease.

Animals↗