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Biomedical subjects

F Wang

Publications and source records attributed to F Wang.

At least 649 records · Page 36Linked to original sources
PubMed1991

Delineation of the cis-acting element mediating EBNA-2 transactivation of latent infection membrane protein expression.

To delineate the cis-acting element through which EBNA-2 transactivates latent membrane protein 1 (LMP1), we assayed the effect of EBNA-2 on the activity of LMP1 promoter upstream deletion mutants in the context of the LMP1 or heterologous promoters controlling chloramphenicol acetyltransferase (CAT) reporter gene expression in Epstein-Barr virus-negative Burkitt lymphoma cells. Assays of progressive 5' deletions of the LMP1 promoter revealed low constitutive and at least eightfold EBNA-2-stimulated activity from -512 to +40 (-512/+40), -334/+40, and -234/+40 LMP1CAT plasmids. More extensive 5'-deleted -205/+40, -155/+40, and -147/+40 LMP1CAT plasmids also had low constitutive activity but were not EBNA-2 responsive. The most 5'-deleted -55/+40 LMP1CAT plasmid had moderate constitutive activity and was not EBNA-2 inducible. Either orientation of the -334/+40 LMP1 sequence conferred EBNA-2 responsiveness when positioned upstream of an enhancerless simian virus 40 or herpes simplex virus thymidine kinase (TK) promoter. EBNA-2 and the cis-acting LMP1 DNA were both required to increase TK promoter-initiated mRNA, indicating that the EBNA-2 effect is at the transcriptional level. Further deletion analysis of the EBNA-2-responsive cis-acting element defined a -234/-92 LMP1 DNA fragment which conveyed EBNA-2 responsiveness to the herpes simplex virus TK promoter. The 5' 30 bp between -234 and -205 were essential for EBNA-2 responsiveness. Thus, these experiments define a 142-bp cis-acting element which is sufficient for conveying EBNA-2 responsiveness and an essential 30-bp component of that element. The role of this element in LMP1 and LMP2B expression and its possible role in LMP2A expression are discussed.

Antigens, Viral↗
PubMed1991

Epstein-Barr virus (EBV) recombinants: use of positive selection markers to rescue mutants in EBV-negative B-lymphoma cells.

The objective of these experiments was to develop strategies for creation and identification of recombinant mutant Epstein-Barr viruses (EBV). EBV recombinant molecular genetics has been limited to mutations within a short DNA segment deleted from a nontransforming EBV and an underlying strategy which relies on growth transformation of primary B lymphocytes for identification of recombinants. Thus, mutations outside the deletion or mutations which affect transformation cannot be easily recovered. In these experiments we investigated whether a toxic drug resistance gene, guanine phosphoribosyltransferase or hygromycin phosphotransferase, driven by the simian virus 40 promoter can be recombined into the EBV genome and can function to identify B-lymphoma cells infected with recombinant virus. Two different strategies were used to recombine the drug resistance marker into the EBV genome. Both utilized transfection of partially permissive, EBV-infected B95-8 cells and positive selection for cells which had incorporated a functional drug resistance gene. In the first series of experiments, B95-8 clones were screened for transfected DNA that had recombined into the EBV genome. In the second series of experiments, the transfected drug resistance marker was linked to the plasmid and lytic EBV origins so that it was maintained as an episome and could recombine with the B95-8 EBV genome during virus replication. The recombinant EBV from either experiment could be recovered by infection and toxic drug selection of EBV-negative B-lymphoma cells. The EBV genome in these B-lymphoma cells is frequently an episome. Virus genes associated with latent infection of primary B lymphocytes are expressed. Expression of Epstein-Barr virus nuclear antigen 2 (EBNA-2) and the EBNA-3 genes is variable relative to that of EBNA-1, as is characteristic of some naturally infected Burkitt tumor cells. Moreover, the EBV-infected B-lymphoma cells are often partially permissive for early replicative cycle gene expression and virus replication can be induced, in contrast to previously reported in vitro infected B-lymphoma cells. These studies demonstrate that dominant selectable markers can be inserted into the EBV genome, are active in the context of the EBV genome, and can be used to recover recombinant EBV in B-lymphoma cells. This system should be particularly useful for recovering EBV genomes with mutations in essential transforming genes.

Animals↗
PubMed1991

Epstein-Barr virus nuclear protein 2 mutations define essential domains for transformation and transactivation.

Epstein-Barr virus (EBV) nuclear protein 2 (EBNA-2) is essential for B-lymphocyte growth transformation. EBNA-2 transactivates expression of the EBV latent membrane protein (LMP-1) and also transactivates expression of the B-lymphocyte proteins CD21 and CD23. In order to analyze the functional domains of EBNA-2, we constructed 11 linker-insertion and 15 deletion mutations. Each of the mutant EBNA-2 proteins localized to the nucleus, and each was expressed at levels similar to wild-type EBNA-2. Deletion of both EBNA-2 basic domains was required to prevent nuclear localization, indicating that either is sufficient for nuclear translocation. The mutant EBNA-2 genes were assayed for lymphocyte transformation after recombination with the EBNA-2-deleted P3HR-1 EBV genome and for LMP-1 transactivation following transfection into P3HR-1-infected B-lymphoma cells. Cell lines transformed by recombinant EBV carrying EBNA-2 mutations were assayed for growth properties and LMP-1, CD21, and CD23 expression. The mutational analysis indicates that at least four separate EBNA-2 domains are essential for lymphocyte transformation. Two other domains are necessary for the full transforming phenotype. Two deletion and eight linker-insertion mutations did not reduce transforming activity. Mutations which diminish or abolish lymphocyte transformation also diminish or abolish LMP-1 transactivation, respectively. Cells transformed by recombinant EBV carrying EBNA-2 genes with diminished or normal transforming activity all expressed high levels of LMP-1, CD23, and CD21. These findings suggest that transactivation of these viral and cellular genes by EBNA-2 plays a critical role in lymphocyte transformation by EBV. Furthermore, these results indicate that the transformation and transactivation functions of EBNA-2 may not be separable.

Amino Acid Sequence↗
PubMed1991

Epstein-Barr virus nuclear protein 2 transactivates a cis-acting CD23 DNA element.

Epstein-Barr virus (EBV) nuclear protein 2 (EBNA-2) is essential for B-lymphocyte growth transformation. EBNA-2 upregulates mRNAs encoding CD23, a B-lymphocyte surface protein closely associated with EBV-induced growth transformation. To further investigate this EBNA-2 effect, we searched in the genomic DNA spanning the type a and type b CD23 mRNA start sites for a cis-acting fragment that would render a promoter transactivatable by EBNA-2. An 800-bp CD23 DNA fragment (-335 to +465 relative to the type a CD23 mRNA start site) conferred EBNA-2 responsiveness to the herpes simplex virus thymidine kinase (TK) promoter when transfected into EBV-negative B-lymphoma cells. Deletional analysis identified a -275/-89 subfragment that was EBNA-2 responsive when cloned in either orientation and at variable distances upstream of the heterologous promoter. EBNA-2 and the cis-acting CD23 element increased TK-promoted mRNA and did not alter the herpes simplex virus TK promoter transcription start site. As expected, a type a CD23 promoter (-335/+80) which contained the EBNA-2-responsive element was transactivated by EBNA-2. As in EBV infection and stable EBNA-2 transfection, the CD23 DNA element in cis with heterologous or homologous promoters was less responsive to type 2 than to type 1 EBNA-2, whereas the EBNA-2-responsive DNA fragment from the EBV latent membrane protein 1 promoter was more responsive to the type 2 EBNA-2. These experiments delineate a 186-bp, EBNA-2-responsive cell DNA fragment and provide firm evidence that EBNA-2 transactivates transcription of cell genes. The greater type 1 versus type 2 EBNA-2 responsiveness of the CD23 promoter and the lack of a similar effect on the latent membrane protein 1 promoter is consistent with the hypothesis that greater cell gene transactivation by type 1 EBNA-2 is the basis for the more efficient growth-transforming properties of type 1 EBV.

Antigens, CD↗
PubMed1991

Anticardiolipin antibodies in patients from Malaysia with systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) is highly prevalent in Malaysia, which has a mixed population of Malays, Chinese, and Indians. A quantitative enzyme linked immunosorbent assay (ELISA) was used to determine anticardiolipin antibody (aCL) levels (total immunoglobulin, IgG, and IgM) in 200 patients with SLE (164 Chinese, 26 Malay, and 10 Indian) attending the University Hospital of Kuala Lumpur, Malaysia, and 103 matched controls. Only 33 (16.5%) of the patients had raised aCL levels; 26 had raised IgG aCL, five IgM aCL, and two both IgG and IgM aCL. There was a low prevalence of raised levels of aCL in the population studied, which was seen in conjunction with a rare occurrence of thrombosis. The classical association of high aCL levels with thrombocytopenia and recurrent abortions was noted, though not with cerebral disease. The low prevalence of aCL in this study population of mixed racial origin contrasts with findings in European patients with SLE and lends support to the influence of local factors, be they genetic or environmental, on the clinical manifestations of this disease.

Abortion, Habitual↗
PubMed1991

Detection of the Na(+)-K(+)-ATPase alpha 3-isoform in multinucleated macrophages.

We previously reported that multinucleated macrophages express a high concentration of Na(+)-K(+)-ATPases that are concentrated on the nonadherent domain of their plasma membrane (A. Vignery, T. Niven-Fairchild, D. H. Ingbar, and M. Caplan. J. Histochem. Cytochem. 37: 1265-1271, 1989). We also showed that an increase in newly synthesized alpha-subunit occurred during cell culture and multinucleation. We now present evidence that macrophage multinucleation in vitro is accompanied by an increased accumulation of Na(+)-K(+)-ATPase alpha-subunit mRNA. Most interesting is the detection of significant amount of both alpha 1- and alpha 3-isoform mRNA and peptide in these cells by in situ hybridization, Northern and Western blot analyses. These qualitative and quantitative variations in Na(+)-K(+)-ATPase expression suggest that macrophage multinucleation is accompanied by a coordinated regulation of gene expression and that multinucleation confers a specific function to macrophages. Multinucleated macrophages offer a novel model system to investigate not only the specific function(s) of the alpha 3-isoform but also the role of the Na(+)-K(+)-ATPase in giant cells and osteoclasts.

Animals↗
PubMed1991

Multinucleated rat alveolar macrophages express functional receptors for calcitonin.

The fusion of mononuclear phagocytes occurs spontaneously in vivo and leads to the differentiation of either multinucleated giant cells or osteoclasts in chronic inflammatory sites or in bone, respectively. Although osteoclasts are responsible for resorbing bone, the functional role of giant cells in chronic inflammatory reactions and tumors remains poorly understood. We recently reported that the plasma membrane of multinucleated macrophages is, like that of osteoclasts, enriched in Na-K-adenosinetriphosphatases (ATPases). We also observed that the localization of their Na-K-ATPases is restricted to the nonadherent domain of the plasma membrane of cells both in vivo and in vitro, thus imposing a functional polarity on their organization. By following this observation, we wished to investigate whether these cells also expressed, like osteoclasts, functional receptors for calcitonin (CT). To this end, alveolar macrophages were fused in vitro, and both their structural and functional association with CT was analyzed and compared with those of mononucleated peritoneal and alveolar macrophages. Evidence is presented that multinucleated alveolar macrophages express a high copy number of functional receptors for CT. Our results also indicate that alveolar macrophages, much like peritoneal, express functional receptors for calcitonin gene-related peptide. It is suggested that multinucleated rat alveolar macrophages offer a novel model system to study CT receptors and that calcitonin may control local immune reactions where giant cells differentiate.

1-Methyl-3-isobutylxanthine↗
PubMed1991

[Investigation of impairment of neutrophil's phagocytosis and bactericidal function in rats with iron deficiency].

Studies were made to determine the neutrophil's phagocytosis and bactericidal function in three groups of rats (control, iron deficiency, and iron supplement). Results showed that there were significant differences in values of chemiluminescence (CL) among three groups. The values of peak CL and five minutes integrated CL were markedly decreased in neutrophils of iron-deficient rats, accounting for only 41% and 32% of the control's values respectively. These suggested that the activity of NADPH oxidase was decreased, and the function of respiratory burst of neutrophils was impaired. The activity of myeloperoxidase in the iron-deficient neutrophils was also significantly lower than that in the control cells. It constituted only 30% of the control's value, indicating that the bactericidal function of neutrophils was injured. One week after iron administration, the low values of the peak CL, the five minutes integrated CL and the activity of myeloperoxidase all went up apparently, but not reached the normal levels yet. The time the function of neutrophils in iron-deficient rats returned to normal may be related to the process of neutrophil maturation in bone marrow.

Anemia, Hypochromic↗
PubMed1991

Damage to hepatic thyroxine 5'-deiodination induced by pathogenic factors of Keshan disease and the preventive effects of selenium and vitamin E.

Experiments were performed to investigate the change of hepatic T4 5'-deiodination and the preventive effects of selenium (Se) and vitamin E in rats fed grains from a Keshan disease (KD) endemic area. The results showed that consumption of the endemic grain for 8 weeks caused a significant reduction in hepatic T4 5'-monodeiodinase and glutathione peroxidase activities, and a marked enhancement of hepatic malondialdehyde content. These changes could be effectively prevented through Se or vitamin E supplementation to the diet. These observations confirm the reduced ability of hepatic T4 5'-deiodination induced by the pathogenic factors existing in the endemic grains, and the preventive effects of selenium and vitamin E on the alterations. The present study suggests that the reduction in hepatic T4 deiodination in these animals may be the consequence of hepatic damage owing to uncontrolled free radical metabolism, and that the relative deficiency of vitamin E, besides selenium deficiency, may also play a role in the pathogenesis of KD.

Animals↗
PubMed1991

Effect of sodium nitrite on myocardial glutathione peroxidase and protective action of vitamin E and selenium.

Under the condition of acute NaNO2 poisoning, the changes of myocardial GSH-Px activity of rats fed a diet composed of grains grown in the endemic region of Keshan disease and the same diet with supplementation of vitamin E or selenium were investigated. By gavage of toxic doses of NaNO2, the myocardial GSH-Px was significantly reduced (P less than 0.05). Vitamin E or selenium supplementation protected the enzyme activity from reducing. It is suggested that the simultaneous action of an increase in selenium and vitamin E intake and a decrease in nitrite intake might greatly prevent the occurrence of Keshan disease.

Animals↗
PubMed1991

Comprehensive assessment of long-term postoperative continence in pediatric imperforate anus. Clinical, manometric and contrast studies.

109 patients with imperforate anus were followed up postoperatively for 5 to 28 years. Postoperative continence was evaluated by anorectal manometry, barium enema and clinical symptoms. A comprehensive assessment system, combining the clinical and objective systems was designed which can reflect postoperative anal continence function completely and objectively. It is useful for determining the causes of incontinence and its treatment.

Adolescent↗
PubMed1991

[Preliminary studies on subtypes of respiratory syncytial virus in China].

An analysis of subtypes of 9 respiratory syncytial (RS) viruses isolated from Guangzhou and Nanjing areas of china was carried out with eight Sweden RS-subtype specific monoclonal antibodies (MAbs) and 7 internal anti-RS MAbs. All these MAbs directed against respectively the large Glycoprotein (G), fusion protein (F), nucleoprotein (NP), and phosphoprotein (P) components of the prototype Long strain of RS virus. The patterns of the reactions of these MAbs to the nine isolated strains of RS virus were compared with indirect immunofluorescence assay (IFA), alkaline phosphoesterase-anti alkaline phosphoesterase (APAAP) enzyme-linked assay and Western blotting. The antigenic variations were founded among the strains of RS virus, and two subtypes allocated to the subtype A and B of RS virus by using the eight RS-subtype specific MAbs. Seven out of the 9 isolated strains of RS virus belonged to the subtype A, and two were being to the subtype B. The antigenic diversities were also founded within the same subtype, and the main pronounced difference were observed on the G glycoprotein by using the internal anti-RS MAbs. These findings are potentially important both for vaccine development and for the understanding of clinical and epidemiological characteristics of RS virus.

Antigenic Variation↗
PubMed1991

Clinical observations on acupuncture treatment of peripheral facial paralysis aided by infra-red thermography--a preliminary report.

We have carried out clinical observations on 34 patients with peripheral facial paralysis treated by acupuncture therapy prescribed according to selection of treatment regimen on the basis of facial thermogram and temperature. A comparison was made with a control group of 97 patients who received conventional acupuncture therapy only. It was found that 1) The cure rate in the group of selecting acupoints by thermogram (hereinafter referred to as the thermography--aided treatment group) was 67.65%, with a marked improvement rate of 26.40%; while the cure rate of the conventional acupuncture treatment group (hereinafter called the conventional treatment group) was 46.39%, the marked improvement rate being 29.90%, indicating a significant difference in therapeutic efficacy between the two groups (P less than 0.02). 2) The average duration of acupuncture therapy for the thermography aided treatment group was 6.02 weeks, whereas that for the conventional treatment group, 24 weeks. There was also a significant difference between the two groups (P less than 0.01). And 3) During the entire therapeutic course, 25.2 sessions of treatment were given on the average in the thermography--aided treatment group, and 78.8 sessions in the conventional treatment group, showing a very significant difference (P less than 0.001). The present thermography--aided method exhibits advantages over the conventional one in enhancing the cure rate and shortening the duration of treatment, which is worthy to be popularized in clinical practice. And it is also of certain significance in standardization and scientification of acupuncture therapy.

Acupuncture Points↗
PubMed1991

[Determination of cholic acid in man-made bezoar by derivative spectrometry].

Cholic acid in man-made bezoar can be determined by the suggested first order derivative spectrometric method. The peak amplitude within 310-290 nm is independent of the other components and only varies linearly with cholic acid concentration. The method is simple and accurate with good reproducibility.

Animals↗
PubMed1991

A comparison of two photographic systems for grading cataract.

Two different systems for classifying lens opacities were compared: the Lens Opacity Classification System version II (LOCS II) and the system developed at Johns Hopkins University. Using the two systems, slit-lamp photographs of the nucleus and retroillumination lens photographs of 100 eyes were graded. Each photograph was graded independently by three trained observers, and the time taken to grade the photographs was similar. Each system uses photographs to define the severity of nuclear opacity and nuclear color, and each showed good interobserver agreement (kappa statistic, greater than 0.6). The method of classifying cortical and posterior subcapsular opacity varied, and although interobserver agreement was acceptable in each system, it was somewhat higher with the Hopkins system. Because different standards and definitions are used to define severity with each system, there was some variation in the classification of individual photographs and corresponding differences in the proportion of photographs in each grade of severity. These data provide a useful cross reference for future comparison of studies using these systems.

Aged↗