Biomedical subjects
Publications and source records attributed to F Wang.
The case of a 3-year-old male child is reported who had a history of congenital hydrocephalus, treated by VP shunting. Severe complications with VP shunting are rare, but in this case the shunt had apparently perforated the liver, causing a pseudocyst to form and subsequent hepatomegaly. The shunt was revised surgically and the pseudocyst resected.
The alteration of sarcolemmal membrane permeability of cardiac muscle cells in rats fed grain from a Keshan disease (KD) endemic area was studied with horseradish peroxidase (HRP) as a tracer. Weanling male rats were divided at random into three groups and fed the following three diets, respectively, for 3 months: a diet with grain from a KD endemic area (Group A), a diet with grain from a KD nonendemic area (Group B), and standard laboratory chow (Group C). At the end of the experiment, HRP was injected intravenously and localized in the ventricular myocardium by light microscopy. The experimental results showed that the percentage of cardiac muscle cells containing HRP reaction product in rats fed grain from the KD endemic area was significantly greater than that in rats fed grain from nonendemic area and standard laboratory chow. This suggests that the sarcolemmal membrane permeability of cardiac muscle cells in rats of Group A was markedly increased. The distribution of cardiac muscle cells with increased sarcolemmal membrane permeability was similar to that seen in the myocardium of KD patients. The present study suggests that the abnormal membrane permeability of cardiac muscle cells may play an important role in the pathogenesis of myocardial necrosis in KD.
Fluorescence enhancement and fluorescence photobleaching recovery have been utilized to examine actin self-assembly over the pH range 6.6-8.0. The kinetics of assembly are faster and the critical concentrations are lower at lower pH. Filament diffusion coefficients are not a function of pH, indicating that average filament lengths are not pH dependent. Although critical actin concentrations are a sensitive function of the concentrations of various cations in the medium, the relative pH dependences of critical concentrations are similar for all combinations of cations employed. The pH dependence of actin self-assembly is sufficiently great that it should be taken into account when comparing data from different reports and when relating in vitro measurements to cytoplasmic mechanisms.
A series of clinical isolates of methicillin resistant Staphylococcus aureus (MRSA) from two hospitals in China was examined. Fragment patterns obtained by digestion of total cellular DNA with restriction enzymes were used to characterize the isolates, in combination with phage-typing, antibiotic resistance profile, and plasmid profile. Digestion of total cellular DNA with restriction enzymes was most useful in discriminating between isolates and yielded additional information on the relatedness of non-identical isolates. In one hospital a single strain, resistant to a large number of antibiotics, had apparently become endemic. In the second hospital a number of distinct but related strains were present. The isolates were also related but not identical to the strain of MRSA endemic at the London Hospital.
Epstein-Barr virus (EBV) efficiently transforms B lymphocytes to perpetual proliferation. The EBV laboratory strain P3HR-1 is transformation-incompetent and lacks a DNA segment that includes the EBV nuclear antigen 2 (EBNA-2) gene and a portion of the EBNA leader protein (EBNA-LP) gene. These two genes are expressed in transformed B lymphocytes. Recombinant transformation-competent EBVs were produced by transfecting P3HR-1-infected cells with a cosmid containing the DNA deleted in P3HR-1. Deletion of 105 nucleotides from the middle of the EBNA-2 gene had no discernible affect on transformation. Two larger EBNA-2 deletions abolished transformation but did not affect EBNA-2 nuclear localization. Two naturally occurring EBV variants (EBV types 1 and 2) differ extensively in their growth-transformation phenotype and in their EBNA-LP, EBNA-2, and EBNA-3A, -3B, and -3C genes. Recombinant P3HR-1 carrying EBV-1 EBNA-2 has many of the EBV-1 in vitro growth-transforming effects; recombinant P3HR-1, isogenic except for EBV-2 EBNA-2, has many of the EBV-2 growth-transforming effects including slow emergence of transformants, growth in tight clumps with few surrounding viable cells, and early sensitivity to dilution with fresh medium. Thus, EBNA-2 is an essential molecule in lymphocyte growth transformation by EBV and a major determinant of the differences between EBV-1 and EBV-2 in lymphocyte growth transformation.
Ofloxacin, 300 mg 12-hourly, was given orally to 64 patients with typhoid fever, all with positive blood cultures. Almost 80% of the isolates were resistant to chloramphenicol, ampicillin and co-trimoxazole, but sensitive to ofloxacin and norfloxacin. Fever subsided within five days in most patients (mean 3.2 +/- 1.1), rates of clinical effectiveness and bacteriological cure both being 100%. Thirty patients were followed for 1-3 months after the completion of therapy with no occurrence of relapse.
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A case of steroid induced exophthalmos in a patient with systemic lupus erythematosus with renal involvement is described. Computed Tomography was used to demonstrate the increased retro-orbital fat.
Latent Epstein-Barr virus (EBV) infection activates B-lymphocyte proliferation through mechanisms which are partially known. One approach to further delineate these mechanisms is to identify cellular genes whose expression is augmented in cells latently infected with EBV. Since EBV-negative Burkitt's lymphoma cells can be grown in continuous culture and EBV can establish growth-altering latent infection in these cells, some effects of EBV on B-lymphocyte gene expression can be studied by using this in vitro system. Pursuing this latter approach, we have used cDNA cloning and subtractive hybridization to identify a gene whose expression is increased after EBV infection. This gene encodes the cytoskeletal protein vimentin. Latent infection of established EBV-negative Burkitt's lymphoma cell lines with the transforming EBV strain, B95-8, resulted in dramatic increases in vimentin mRNA and protein levels, while infection with the nontransforming P3HR1 strain failed to do so. Vimentin induction was reproduced by the expression of the single EBV gene which encodes the latent infection membrane protein (LMP). An amino-terminal LMP deletion mutant did not induce vimentin. These results are of particular interest in light of the transforming potential of LMP, as demonstrated in rodent fibroblasts, and the interaction between vimentin and LMP observed in immunofluorescent colocalization and cell fractionation studies.
The power spectrum of electrocochleogram in Ménière's disease was analysed. Usually, the ratio -SP/AP was used to diagnose Ménière's disease. However, when -SP could not be discriminated exactly, we were dubious of using this method. With power spectrum, we can raise the rate of diagnosis and estimate the condition of endolymphatic hydrops. In power spectrogram it shows more components of low frequency (that is, the power peak moves to the left) when the amplitude of -SP goes higher. Extratympanic electrocochleography was performed on 34 ears diagnosed as having Ménière's disease (MD group) and on 8 normal ears (normal group). An obvious difference in power spectrogram was found between these two groups (P less than 0.01). The peak in spectrogram of normal group was mean = 594 Hz; S = +60 Hz; the peak in MD group was mean = 359 Hz; S = +161 Hz. In MD group there were 28 cases (82.4%) with power peak moved to the left and 18 cases (52.9%) with the ratio -SP/AP no less than 0.4. During remission, the spectrum resembled the normal ones.
Active opioid binding protein was partially purified from rat brain by Vicia bungei Ohwi lectin (VBL). Mannose also existed in opioid receptors since the binding between opioid binding protein and VBL is specific, via alpha-methyl-D-mannoside (MeMan) residues. Since the active opioid binding protein purified by VBL chromatography was enriched about 200-folds. VBL can be used as effective purification tool which is much better than wheat germ agglutinin (WGA), a lectin commonly used in purifying opioid receptor.
We studied 75 patients (36 males and 39 females), suffering from typhoid fever. 64 patients were treated with ofloxacin and 11 with amikacin, dosage regimens of the two drugs were 300 mg and 300-400 mg twice daily. Clinical effective rate was 100% with ofloxacin and 36.4% with amikacin. A total of 72 strains of salmonella typhi was isolated from all the patients of both groups. Bacteriological elimination rate was 100% with ofloxacin after treatment. Sensitive rates for S. Typhi isolated was 100% with ofloxacin, norfloxacin and ceftriaxone, 98.6% with amikacin and 20-21.4% with chloramphenicol, ampicillin and sulfamethoxazole Co. There were fewer adverse reactions and better acceptance, one had skin rash and one had gastrointestinal disturbance. In amikacin group, abnormality of urine routine and serum creatinine was observed. Ofloxacin was well absorbed orally. Its high bioavailability, satisfactory therapeutic efficacy excellent tolerability and convenience for use make it a very useful medication in the therapy of typhoid fever resulted from multiresistant strains.
Two hundred and five healthy Malaysian adults were scanned for the length of their kidneys and the cortical thickness by both the sector real time and linear array static B-scan diagnostic ultrasound. The length of the left kidney was found to measure 105 (98-111) mm for males, and 100 (94-106) mm for females on average from the sector scan and the static B-scan. The right renal length was 102 (96-119) mm for males, and 98 (92-103) mm for females on the average from readings of both scans. The left kidney is longer in length than the right kidney in males and females on both scans. The cortical thickness at the equator of the kidneys of males and females ranges from 12-14 mm. In both sexes, the lengths of the kidneys may be estimated by the distance between the first to the fourth lumbar transverse processes when there is no scoliosis.
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Properties of filamentous acetamidofluorescein-labeled actin and acetamidotetramethylrhodamine-labeled actin (AF and ATR-actin, respectively) were examined to resolve discrepancies in the reported translational diffusion coefficients of F-actin measured in vitro by FPR and other techniques. Using falling-ball viscometry and two independent versions of fluorescence photobleaching recovery (FPR), the present data indicate that several factors are responsible for these discrepancies. Gel filtration chromatography profoundly affects the viscosity of actin solutions and filament diffusion coefficients. ATR-actin and, to a lesser degree, AF-actin show a reduction in viscosity in proportion to the fraction labeled, presumably due to filament shortening. Actin filaments containing AF-actin or ATR-actin are susceptible to photoinduced damage, including a covalent cross-linking of actin protomers within filaments and an apparent cleavage of filaments detected by a decrease of the measured viscosity and an increase in the measured filament diffusion coefficients. Quantum yields of the two photoinduced effects are quite different. Multiple cross-links are produced relative to each photobleaching event, whereas less than 1% filament cleavage occurs. Substantial differences in the filament diffusion coefficients measured by FPR are also the result of differences in illumination geometry and sampling time. However, under controlled conditions, FPR can be used as a quantitative tool for measuring the hydrodynamic properties of actin filaments. Incremented filament shortening caused by photoinduced cleavage or incremental addition of filament capping proteins produces a continuous and approximately linear increase of filament diffusion coefficients, indicating that filaments are not associated in solution. Our results indicate that actin filaments exhibit low mobilities and it is inferred that actin filaments formed in vitro by column-purified actin, under standard conditions, are much longer than has conventionally been presumed.
Cytotoxic T cells from Epstein-Barr virus (EBV)-immune individuals specifically kill EBV-transformed B cells from HLA class I antigen-matched donors even though the latently infected cells express only a restricted set of virus genes. The virus-induced target antigens recognized by these immune T cells have not been identified. In our experiments, EBV DNA sequences encoding the virus latent gene products Epstein-Barr nuclear antigen (EBNA)1, EBNA 2, and EBNA-LP and the latent membrane protein (LMP) were individually expressed in a virus-negative human B-lymphoma cell line, Louckes. Transfected clones expressing LMP were killed by EBV-specific cytotoxic T-cell preparations from each of three virus-immune donors HLA matched with Louckes through HLA-A2, B44 antigens; control transfectants or clones expressing one of the EBNA proteins were not recognized. Expression of LMP in a second virus-negative B-cell line, BL41, sensitized these cells to EBV-specific cytolysis restricted through the HLA-A11 antigen. To distinguish between the viral protein and an induced human B-cell activation antigen as the target for T-cell recognition, LMP was then expressed in a murine mastocytoma cell line, P815-A11-restricted human T cells. The LMP-expressing P815-A11 transfectants were susceptible to lysis by EBV-specific cytotoxic T cells from three HLA-A11-positive individuals. Both Louckes and P815-A11 cells were also transfected with constructs capable of encoding a truncated form of LMP (Tr-LMP) which lacks the N-terminal 128 amino acids of the full-length protein. Tr-LMP-expressing transfectants were not recognized by the above T-cell preparations. The results suggest that LMP, and, in particular, epitopes derived from the N-terminal region of the protein, provides one of the target antigens for the EBV-induced human cytotoxic T-cell response.