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Biomedical subjects

H C Wang

Publications and source records attributed to H C Wang.

At least 19 recordsLinked to original sources
PubMed1992

Clinicopathological evaluation of 78 astrocytomas in Taiwan with emphasis on a simple grading system.

The grading systems of astrocytic tumors have long been the subject of controversy. A simple, objective and effective grading method is urgently needed for the evaluation of prognosis and the planning of treatment. This study investigated the relationship of clinical prognostic factors to the grading method of Daumas-Duport. This method determines the grade of tumor based on the presence or absence of four morphological criteria: nuclear atypia, mitosis, endothelial proliferation, and necrosis. A total of 143 astrocytic tumors were reviewed and screened, of which 65 ordinary and 13 pilocytic astrocytomas were selected for grading and comparison. Among ordinary astrocytomas, the grading method distinguished 9.2% grade 1, 26.2% grade 2, 36.9% grade 3, and 27.6% grade 4. At least 2-year follow-up was available on all surviving patients. Median survival was 57, 32, 12.5, and 8 months in grades 1, 2, 3, and 4 tumors, respectively. By a multiple regression model and analysis of variance, grade is significantly associated with survival (total regression coefficient r = 0.711). Age lost its significance on survival after multiple regression analysis. Sex, location, and surgical procedure were all unrelated to survival after regression. The age distribution and survival of patients with pilocytic astrocytomas revealed that this is a distinct disease entity and should not be admixed with ordinary astrocytomas in a grading scheme.

Adolescent↗
PubMed1992

Analysis of peripheral blood of pregnant women for the presence of fetal Y chromosome-specific ZFY gene deoxyribonucleic acid sequences.

Deoxyribonucleic acid sequences of human ZFY (zinc-finger-Y) gene, a Y-chromosome-specific gene and candidate for the testis-determining factor, has been identified by an in vitro enzymatic deoxyribonucleic acid amplification method in peripheral blood specimens of women pregnant with male fetuses. This technique permits detection of ZFY gene deoxyribonucleic acid sequences in as few as a single male cell among 1,000,000 female cells. Maternal blood results were confirmed by amplification of ZFY gene deoxyribonucleic acid sequences in chorionic villus cells and by karyotyping in 33 of 36 pregnant women. There was no false-positive male result, and two of the three blood specimens with false-negative results were obtained from pregnant women at a very early gestational age. With properly designed guidelines, this deoxyribonucleic acid amplification method may be an alternative to determine the fetal sex for those pregnancies at risk for X-linked genetic disorders.

Base Sequence↗
PubMed1992

Activation of protein serine/threonine kinases p42, p63, and p87 in Rous sarcoma virus-transformed cells: signal transduction/transformation-dependent MBP kinases.

We have used myelin basic protein immobilized in sodium dodecyl sulfate-polyacrylamide gels to identify protein kinases after gel electrophoresis, followed by protein kinase reactions. This technique has permitted us to detect three protein kinases in serum-deprived cells transformed by p60src. On induction of cellular transformation by a temperature-sensitive v-src, a p87 protein kinase is activated within 30 min and remains activated in fully transformed cells. The p63 protein kinase is not fully activated until 24 h but remains activated in transformed cells. The commonly studied p42MBPK is rapidly activated within 30 min, and its kinase activity decreases significantly by 24 h, when the p63 enzyme is fully activated. The p42MBPK, as well as the p63 and p87 enzymes, are stimulated by transforming p60c-src mutants but not normal c-src or nonmyristylated p60c-src. In addition, the kinase activity of p63 enzyme, but not of p42MBPK, can be induced in okadaic acid-treated chicken embryo fibroblasts, indicating that phosphatase 2A and/or phosphatase 1 may be involved in the regulation of its activity. Additional data indicate that either p42MBPK or p63 activity correlates with the stimulation of the protein kinase p90RSK. Thus, there may be two independent pathways leading to the activation of the RSK gene product.

Animals↗
PubMed1992

[The role of total gastrectomy in the management of gastrinoma syndrome].

Total gastrectomy used to be considered as a standard operation in the surgical treatment for gastrinoma syndrome. Although this end organ resection is a good palliation, to cure this ulcerogenic disease, gastrinoma resection is preferred. It remains a question if a total gastrectomy is necessary when a gastrinoma is found and resected. In a period of 12 years, nine out of 17 patients with gastrinoma syndrome were surgically treated. Fifteen gastrinomas were removed without histologic evidence of malignancy. Total gastrectomy was added in three, Whipple's operation was done in one and tumor resection alone in five. Serial examination of the resected stomach didn't find any gastrinoma. Eight gastrinomas of seven patients were found located in the pancreas, duodenum and lymph nodes within the gastrinoma triangle. These patients except one were followed up for six months to five years (mean 32 months). One died of post-operative hepatic failure, and one died of hypophysectomy for a co-existent huge prolactinoma (MEN I) four years later. Cure of the disease in terms of normal fasting serum gastrin levels, symptom free without medication, endoscopic evidence of healed ulcer, and a negative conversion of secretin provocative test was found in 2/3 of the patients with additional total gastrectomy, and 4/6 of the others. All cured patients had their gastrinomas located in the gastrinoma triangle, and six of the seven (85.7%) patients with gastrinomas in the triangle were cured. It is our conclusion that total gastrectomy was retrospectively unnecessary in most of the patients with gastrinomas in the gastrinoma triangle. Staged operations should be planned.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

The SH2 and SH3 domains of pp60src direct stable association with tyrosine phosphorylated proteins p130 and p110.

Transformation of chicken embryo cells with the tyrosine kinase oncogene src results in the tyrosine phosphorylation of numerous cellular proteins. We have recently generated monoclonal antibodies to individual tyrosine phosphorylated cellular src substrates, several of which are directed to the phosphotyrosine-containing proteins p130 and p110. These proteins form stable complexes with activated variants of pp60src. Mutagenesis of the src homology domains (SH2 and SH3) of activated pp60src resulted in src variants with altered association with p130 and p110. Analysis of these variants showed that the SH3 domain was required for association of p110, while the SH2 domain contained residues necessary for the formation of the ternary complex involving p130, p110 and pp60src. Both the tyrosine phosphorylation status and pp60src association of p130 and p110 appeared to correlate, in part, with the extent of cell transformation. Biochemical analysis demonstrated that p130 and p110 were substrates of both serine/threonine and tyrosine kinases. In addition, p130 was redistributed from the nucleus to cellular membranes upon src transformation, whereas p110, which normally colocalized with cytoskeletal elements, was observed in adhesion plaques (podosomes) in src transformed cells. These data indicate that tyrosine phosphorylation of two different phosphoproteins may play a role during src transformation either by directing their interaction with pp60src, by redirecting subcellular distribution or both.

Animals↗
PubMed1991

Immunohistochemical detection of HBsAg and HBcAg in the liver of patients with schistosomiasis japonica complicated by hepatocellular carcinoma.

In liver biopsies from 21 patients with schistosomiasis japonica complicated by hepatocellular carcinoma (HCC), 69 patients with advanced schistosomiasis japonica, and 25 patients with HCC, HBsAg and HBcAg were investigated with peroxidase-antiperoxidase technique. The positive rate of HBAg (i.e. HBsAg and/or HBcAg) in the liver of patients with schistosomiasis japonica complicated by HCC was significantly higher than in the group of advanced schistosomiasis japonica, but similar to that in cases of HCC. The location of carcinoma cells in the liver was not related to the distribution of Schistosoma ova in patients with schistosomiasis japonica complicated by HCC. The results indicated that the complication with hepatitis B virus infection may be one of the major factors involved in the development of HCC in patients with schistosomiasis japonica.

Biopsy, Needle↗
PubMed1991

Changes in the level of IL-2, T cell subsets and the function of T suppressor cells in patients with schistosomiasis japonica.

The level of interleukin-2 (IL-2) produced by peripheral blood mononuclear cells in vitro, T cell subsets and the function of T suppressor cells (Ts) in patients with schistosomiasis japonica were investigated. It was found that the level of IL-2 induced by schistosomal antigens was significantly high and positively related to the percentage of CD4+ cells. In the groups of chronic and advanced schistosomiasis japonica, the level of IL-2 induced by schistosomal antigens was markedly lower than that in the group of acute schistosomiasis japonica, but significantly higher than that in the group of normal controls. The IL-2 level was negatively related to the percentage of CD8+ T cells and the ratio of CD4+/CD8+. The level of IL-2 induced by PHA was greatly reduced in the group of advanced schistosomiasis japonica. The changes in the level of IL-2 and its relationship with T cell subsets and the function of Ts are also discussed.

CD4-CD8 Ratio↗
PubMed1991

Intraamniotic detection of Chlamydia trachomatis deoxyribonucleic acid sequences by polymerase chain reaction.

The presence of Chlamydia trachomatis in cervicovaginal cells and amniotic fluid of pregnant women was examined by culture and by polymerase chain reaction deoxyribonucleic acid amplification methods. Chlamydial deoxyribonucleic acid sequences were found in nine of 31 (29.0%) cervicovaginal cell specimens, five of which also were positive by culture method. Amniotic fluid specimens from two of the nine (22.2%) cervicovaginal chlamydial deoxyribonucleic acid-positive women and none from the remaining 22 cervicovaginal chlamydial deoxyribonucleic acid-negative women were found to contain chlamydial deoxyribonucleic acid. The results underscore the significance and frequency of intraamniotic chlamydial infection in women with urogenital chlamydial infections.

Amniotic Fluid↗
PubMed1991

Gene expression in Xenopus oocytes.

1. Gene expression in Xenopus oocytes is now an integral part of many molecular cloning strategies. 2. For some genes, such as those encoding the ion channels, this system has emerged as the only available means to authenticate and examine the biological activities of the cloned DNA. 3. This review discusses some of the current applications of Xenopus oocytes in modern molecular biology.

Animals↗
PubMed1991

Screening for potassium channel modulators by a high through-put 86-rubidium efflux assay in a 96-well microtiter plate.

A rapid and sensitive 86Rb efflux assay to detect chemical compounds capable of modulating the ATP-dependent potassium (KATP) channel is described. This assay, which is performed in a 96-well microtiter plate, utilizes a substrate adherent cell line as the target, requires a small amount of 86Rb as the tracer, and is a suitable system for performing the biochemical and pharmacological characterization of the KATP-channel and its activators. Because this assay is amenable to automation, it presents a useful means for high-volume screening of chemical compounds on a routine basis.

Adenosine Triphosphate↗
PubMed1991

Transformation by pp60src or stimulation of cells with epidermal growth factor induces the stable association of tyrosine-phosphorylated cellular proteins with GTPase-activating protein.

GTPase-activating protein (GAP) is a cytosolic protein that stimulates the rate of hydrolysis of GTP (GTP to GDP) bound to normal p21ras, but does not catalyze the hydrolysis of GTP bound to oncogenic, activated forms of the ras protein. Transformation of cells with v-src or activated transforming variants of c-src or stimulation of cells with epidermal growth factor resulted in the stable association of GAP with two tyrosine-phosphorylated cellular proteins of 64 kDa (p64) and 190 kDa (p190). Analysis of GAP immune complexes isolated from extracts of metabolically labeled src-transformed cells and epidermal growth factor-stimulated cells indicated that tyrosine phosphorylation of p64 and p190 appeared to be coincident with the stable association of these proteins with GAP. Quantitation of the amount of p64 associated with GAP in v-src-transformed cells, however, indicated that only 15 to 25% of tyrosine-phosphorylated p64 was found in complex with GAP. Mutations within the SH2 region of pp60src that render activated pp60src defective for transformation inhibited the efficient formation of complexes between GAP and the tyrosine-phosphorylated forms of p64 and p190. From these data, we suggest that tyrosine phosphorylation and stable association of p64 with GAP is an important step in mediating cellular signaling through the p21ras-GAP pathway.

Animals↗
PubMed1991

Clinical manifestations and thyrotropin releasing hormone therapy in cerebellar degenerations.

Twenty-nine documented cases of cerebellar degeneration at the National Taiwan University Hospital during a 8-year period (1980 through 1987) were reviewed. They were classified as familial (N = 14) or sporadic (N = 15) to compare the clinical signs and symptoms between both groups. The familial cases had earlier onset, and gaze paresis was found only in this group. Patients younger than 30 years old were more often familial cases and had more frequent deep sensation involvement. Oculomotor abnormalities on electrooculographic (EOG) tracings of 21 patients were analysed. The defects included abnormal OKN (86%), jerky pursuit (76%), ocular dysmetria (57%), slow saccades (43%), abnormal VOR or VVOR (43%), and fixation instability (19%). Intravenous TRH therapy was used in 17 patients, and resulted in 8 (47%) subjectively and 6 (35%) objectively improved cases. The use of TRH therapy in cerebellar degeneration was discussed.

Central Nervous System↗
PubMed1991

Lumbar intervertebral disc prosthesis. An experimental study.

To provide a more effective treatment and improve the outcome of surgical treatment of lumbar intervertebral disc protrusion, the values of lumbar intervertebral disc prosthesis (LIDP) were investigated. LIDP was specially designed and made of silicone rubber. The properties of material mechanics were investigated by compressive test and damage test of LIDP specimens. The biocompatibilities of LIDP were observed experimentally in monkeys. The surgical applicabilities were studied by in vitro experiments of fresh human lumbar spine. The results showed that LIDP has the advantages of good biomechanical applicability, biocompatibility and surgical applicability. LIDP is able to maintain the intervertebral space, stress balance and stability of the lumbar spine. after lumbar intervertebral disc excision, the replacement of LIDP could restore the functions of the lumbar spine and improve the curative results of disc excision.

Adult↗
PubMed1991

A study on the mutagenicity of 102 raw pharmaceuticals used in Chinese traditional medicine.

The mutagenic potential of traditional Chinese drugs was studied. After extraction with boiling water and frozen vacuum drying, preparations from 102 raw drugs were tested with the Ames test, and the micronucleus and chromosomal aberration assays in mice in vivo. Astragalus mongholicus Bunge (+S9), Sophora japonica L. (+/- S9) and Eucommia ulmoides Oliv. (+/- S9) were found to significantly induce His+ revertants in Salmonella typhimurium TA98 and/or TA100. Besides these 3, 10 other extracts were positive in the chromosomal aberration and micronucleus assays in mice. They are Datura metal L., Artemisia capillaris Thunb., Carthamus tinctorius L., Forsythia suspensa Thumb., Rehmannia glutinosa f. Hueichingensis (fermented), Paeonia suffruticosa Andr., Platycodon grandiflorum Jacq. DC., Cinnamomum mairei Levl., Notopterygium incisium Ting., and Sophora flavescens Ait. The relevance of these findings is discussed.

Animals↗
PubMed1990

Separation and characterization of the metabolic products of lappaconitine in rat urine by high-performance liquid chromatography.

The separation and characterization of the metabolic products of lappaconitine in rat urine by high-performance liquid chromatography with electrochemical and ultraviolet detection are described. Urine samples from rats intravenously administered lappaconitine hydrobromide were extracted with chloroform and then purified on a Sep-Pak C18 cartridge. The subsequent resolution into individual compounds was achieved by high-performance liquid chromatography. Identification of these compounds was based on comparisons of the chromatographic behaviour and the detector response with those of authentic samples. Changes in the ratio of lappaconitine to its metabolites in rat urine with time after dosing led to a proposal for one of the probable metabolic pathways of lappaconitine in the rat.

Aconitine↗
PubMed1990

Studies on the metabolism of lappaconitine in humans. Identification of the metabolites of lappaconitine in human urine by high performance liquid chromatography.

The metabolites of lappaconitine in the urine of humans having been previously administered intramuscularly with lappaconitine hydrobromide were studied using high performance liquid chromatography with electrochemical and ultraviolet detection. The urine was extracted by means of liquid- and solid-phase extractions. Each of the metabolites of lappaconitine was purified by high performance liquid chromatography on a reversed phase column and identified on the basis of the chromatographic behaviour and the detector response. It was proved that lappaconitine, N-deacetyl-16-O-demethyllappaconitine and N-deacetyllappaconitine were excreted in urine from humans receiving lappaconitine.

Aconitine↗