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Biomedical subjects

J C Wu

Publications and source records attributed to J C Wu.

At least 127 records · Page 7Linked to original sources
PubMed1998

Diagnostic value of anti-hepatitis D virus (HDV) antibodies revisited: a study of total and IgM anti-HDV compared with detection of HDV-RNA by polymerase chain reaction.

A high serum titre (> or = 1000 or > or = 5000) of total antibody to hepatitis D virus (anti-HDV) and positive for immunoglobulin (Ig)M anti-HDV have been used to represent HDV replication, while reverse transcription-polymerase chain reaction (RT-PCR) is currently the most sensitive assay for detecting HDV viraemia. The aim of the present study was to re-evaluate the correlation of total anti-HDV and IgM anti-HDV with HDV viraemia based on RT-PCR and to assess the clinical significance of these markers in acute and chronic HDV superinfection. Chronic HDV infection was defined as positive HDV-RNA by RT-PCR for more than 6 months, while total anti-HDV titre was defined by serial dilution. Of 178 hepatitis B virus (HBV) carrier patients studied, 119 cases had been anti-HDV positive for more than 6 months. Two-thirds (79/119) were positive for HDV viraemia by RT-PCR. Only half the chronic HDV viraemic patients had a high titre (> or = 1000) of total anti-HDV, and there was only moderate agreement (kappa = 0.41) between total anti-HDV titre/IgM anti-HDV and HDV-RNA and chronic HDV viraemia. Based on cross-sectional and longitudinal follow-up analyses, serum total anti-HDV titres > or = 100 appeared to be an excellent cut-off titre (kappa = 0.91) in differentiating chronic from acute HDV infection among viraemic patients. In summary, IgM and a high titre total of anti-HDV are not good markers of HDV viraemia, but an anti-HDV titre of > or = 100 appears to be an excellent marker for the differentiation of acute from chronic HDV superinfection.

Acute Disease↗
PubMed1998

Evidence of transmission of hepatitis B virus to spouses from sequence analysis of the viral genome.

Heterosexual contact is one of the common routes of transmission for hepatitis B virus (HBV) among adults in Taiwan, but only a few studies have provided direct evidence at the level of the HBV genome of infected couples with acute non-fulminant hepatitis to document a common source. By cloning and sequencing polymerase chain reaction-amplified HBV-DNA, we analysed the sequences of the conserved region of the surface gene (nucleotide (n.t.) 305-513, representing 6.5% of the viral genome) of HBV in five HBV-infected index patients, their spouses and four randomly selected HBV carriers as controls. Risk factors associated with acute HBV infection in index cases were sexual contact with their spouses within 3 months before the onset of hepatitis. For all five couples, the HBV-infected index patient and the spouse shared a 100% sequence homology of HBV-DNA. In contrast, there was significantly more variation (mean heterogeneity 6.1%, range 1-13.9%) in the amplified region between the five couples and between each couple and the controls (P<0.001). This study demonstrated that sequence analyses can correlate well with epidemiological findings and confirm the value of the molecular approach for linked infections of HBV through heterosexual contact between spouses. Susceptible adults should receive vaccination.

Adult↗
PubMed1998

Clinical significance of serum auto-antibodies in Chinese patients with chronic hepatitis C: negative role of serum viral titre and genotype.

Positive serum anti-nuclear antibody (ANA) and anti-smooth muscle antibody (SMA) have been reported in 10-66% of patients with chronic hepatitis C virus (HCV) infection from Western countries. However, the mechanism involved in this immunological disorder is still unknown. This study was carried out to evaluate the prevalence and clinical significance of positive serum auto-antibodies in Chinese patients with chronic hepatitis C and to assess the role of serum HCV-RNA titre and HCV genotype in the presence of serum auto-antibodies. Serum ANA, SMA and anti-mitochondrial antibody (AMA) were measured in 122 patients with chronic hepatitis C. Clinical, biochemical and virological data (serum HCV-RNA titre and HCV genotype) were compared between patients with and without serum auto-antibodies. Fifty-eight (48%) patients were associated with positive serum auto-antibodies: 42 (34%) positive for ANA, six (5%) positive for SMA, nine (7%) positive for both ANA and SMA and one (1%) positive for AMA. Clinical parameters (age, sex, blood transfusion history), liver biochemical tests, the presence of cryoglobulinaemia or cirrhosis, and the response to interferon treatment were not significantly different between patients with and without positive serum auto-antibodies. Serum HCV-RNA levels and HCV genotypes were also not significantly different between the two groups. Logistic regression analysis showed that none of the previously mentioned parameters were significant predictors to associate with serum auto-antibodies in chronic hepatitis C. We concluded that 48% of Chinese patients with chronic hepatitis C were associated with positive serum auto-antibodies. Hepatitis C virus genotypes and serum HCV-RNA levels were not correlated to the presence of serum auto-antibodies. The clinical significance and actual pathogenesis of this phenomenon remain to be clarified.

Antibodies, Antinuclear↗
PubMed1998

Relationships between serum aminotransferase levels, liver histologies and virological status in patients with chronic hepatitis C in Taiwan.

In patients with chronic hepatitis C, the relationships between serum alanine aminotransferase (ALT) levels, histological liver injury and serum hepatitis C virus (HCV) RNA titres remain controversial. To evaluate these relationships, 93 Chinese patients with histological diagnosis of chronic hepatitis C were enrolled for this study. Serum ALT levels, HCV-RNA titres and HCV genotypes were examined. The histology was evaluated according to a modified histological activity score based on the degree of periportal necro-inflammation, intralobular necro-inflammation, portal inflammation, total necro-inflammation and fibrosis. The mean serum ALT level was significantly higher in patients with severe intralobular necro-inflammation activity than in patients with mild or no activity (P = 0.013). However, scores of intralobular activity were only weakly correlated with serum ALT levels (r = 0.27) and could not be used to adequately predict ALT values. Serum ALT levels showed no significant correlation with the scores of portal inflammation, periportal necro-inflammation, total necro-inflammation and fibrosis. Also, there was no significant difference in the mean serum ALT level among different serum HCV-RNA levels and HCV genotypes. Serum HCV-RNA titres and genotypes showed no significant correlation with liver histology and serum HCV-RNA titres were only weakly correlated with the total necro-inflammatory score (r = 0.27). In conclusion, although serum ALT levels were higher in patients with more severe intralobular necro-inflammatory activity, the correlation was not strong enough to adequately predict ALT values. Serum HCV-RNA titres and genotypes also showed no significant correlation with serum ALT levels and liver histologies.

Alanine Transaminase↗
PubMed1998

PET scan findings in a patient with a remote history of exposure to organic solvents.

This is a single-case study employing positron emission tomography (PET) scanning and neuropsychological assessment on a 47-year-old male with a 15-year history of repeated respiratory and dermal exposure to high levels of organic solvents with at least 750 peak exposures (i.e., solvent "intoxication"). At age 43, he presented with neuropsychological symptoms of a solvent encephalopathy and multiple abnormalities in his peripheral neurological examination but had normal MRI and EEG findings. Four years after cessation of exposure to degreasing and solvent chemicals, the patient produced a grossly abnormal PET scan in which frontal, hippocampal, and parietal hypometabolism were particularly noteworthy. During this same 4-year period of nonexposure, modest improvements in neuropsychological testing were noted, along with substantial improvements in partial seizurelike symptoms. Frontal lobe deficits elicited in testing and from collateral interview, however, did not change. Findings suggest that repeated peak exposures to organic solvents m y result in a neurobehaviorally complex solvent syndrome caused by central nervous system damage that is readily apparent on PET scan, even though it is not evident in either imaging technologies. In addition, the case is the first reported in which functional neuroimaging was employed to study a patient with chronic solvent encephalopathy many years after cessation of solvent exposure.

Journal Article↗
PubMed1998

[Effects of receptor-mediated endocytosis on macrophage membrane potential, cytosolic pH and lysosomal pH].

The effects of Con A, WGA, Zymosan A on membrane potential, cytosolic pH and lysosomal pH of cultured mouse macrophages were measured with fluorescence method. The results showed all the three kinds of ligands caused macrophage membrane potential hyperpolarization, cytosolic acidification and lysosomal alkalization, but reached their stabilized conditions at different times. The acidification of cytosl might inhibit further endocytosis. Alkalization of lysosomes was a basic factor for exocytosis of lysosomal contents. These receptor-mediated induced changes reflected cellular self-regulation and self-protection.

Animals↗
PubMed1998

[Receptor-mediated endocytosis induced macrophage cytosolic acidification and exocytosis].

The effects of Con A, WGA, Zymosan A on macrophage cytosolic pH and outflow of lysosomal content through exocytosis were studied with SNAFL-calcein and FITC-Dextran on ACAS570. The results showed all three ligands could induce macrophage cytosolic acidification in about 10 min and kept at the same level hereafter; outflow of lysosomal fluorescent probe through exocytosis appeared in 15-20 min. In resting conditions, macrophage lysosomes mainly distributed in cell center; after stimulated for 15 min by three ligands, the number of lysosomes increased in membrane periphery, in 25-30 min lysosomes moved back toward cell center. We proposed that ligands induced lysosomal pH rises was a basic factor for outflow of lysosomal content through exocytosis, cytosolic acidification inhibited receptor-mediated endocytosis. Cytosolic acidification and outflow of lysosomal content through exocytosis were the results of cellular self-regulation and self-protection during receptor-mediated endocytosis.

Animals↗
PubMed1998

Limitations of dobutamine for enhancing flow heterogeneity in the presence of single coronary stenosis: implications for technetium-99m-sestamibi imaging.

UNLABELLED: Dobutamine is used as an alternative to exercise in conjunction with 99mTc-sestamibi SPECT perfusion imaging for detection of coronary artery disease. However, the use of quantitative dobutamine 99mTc-sestamibi SPECT imaging for enhanced detection of coronary stenosis has not been established. The goal of this study is to examine the effects of dobutamine stress on regional myocardial blood flow and relative myocardial 99mTc-sestamibi activity in the presence of a single-vessel stenosis. METHODS: In six open-chest dogs with left circumflex artery stenosis, radiolabeled microspheres were injected during baseline, severe stenosis and peak dobutamine stress (10 microg/kg/min). Technetium-99m-sestamibi was injected intravenously at peak dobutamine. Hearts were excised 20 min after 99mTc-sestamibi injection for SPECT imaging and post-mortem gamma-well counting. RESULTS: Dobutamine significantly increased heart rate, rate-pressure product and the first derivative of left ventricular pressure. Ischemic zone (left circumflex) myocardial blood flows (in ml/min/g) were: baseline, 0.92 +/- 0.15; stenosis, 0.65 +/- 0.16; and dobutamine, 1.19 +/- 0.38. Nonischemic zone myocardial blood flows were: baseline, 0.99 +/- 0.18; stenosis, 1.01 +/- 0.12; and dobutamine, 1.94 +/- 0.32 (p < 0.01 versus stenosis). Ischemic flows, expressed as percentages of nonischemic flows, were: baseline, 94% +/- 2%; stenosis, 63% +/- 11% (p < 0.05 versus baseline) and dobutamine, 60% +/- 12% (p was not significant versus stenosis). Technetium-99m-sestamibi activity in the ischemic zone (75% +/- 6% nonischemic) underestimated the relative flow deficit produced during dobutamine stress (p = 0.056). Myocardial 99mTc-sestamibi activity correlated with flow when flow was less than 1.0 ml/min/g. At higher flow ranges (1.0 ml/min/g-3.5 ml/min/g), 99mTc-sestamibi did not track flow. CONCLUSION: In a canine model of flow-limiting, single-vessel stenosis, dobutamine (10 microg/kg/min) did not augment flow heterogeneity. In addition, relative myocardial 99mTc-sestamibi activity underestimated microsphere flow at higher flows induced by dobutamine, leading to underestimation of ischemia. These findings suggest that dobutamine stress 99mTc-sestamibi scintigraphy may underestimate the relative flow deficit.

Animals↗
PubMed1998

Functional pancreatic islet cell tumors with liver metastasis: the role of cytoreductive surgery and transcatheter arterial chemoembolization: a report of five cases.

Malignant pancreatic islet tumors are slow-growing tumors. Their relatively benign behavior makes aggressive treatment worthwhile. From January, 1987, to January, 1998, five cases of malignant pancreatic islet tumors with liver metastasis were diagnosed at the Veterans General Hospital-Taipei. Of these, three were gastrinomas and the others were vasoactive intestinal peptide (VIPoma, 1 case) and insulinoma (1 case). Four patients (3 with gastrinomas and 1 with insulinoma) had undergone cytoreductive surgery when the diagnosis of metastasis was made. All five patients underwent transcatheter arterial chemoembolization (TACE). All patients had improved symptoms after cytoreductive surgery and TACE. The survival of patients who underwent combined surgery and TACE was 38 and 17 months in the two gastrinoma cases, more than eight months in one gastrinoma case and more than 20 months in the insulinoma case (these 2 patients are still alive). One VIPoma patient who underwent TACE survived for 12 months. In conclusion, treatment for metastatic pancreatic islet cell tumors require a multidisciplinary approach. Metastasis of the tumor is not a contraindication for aggressive therapy. Combined cytoreductive surgery and TACE can relieve symptoms and are of benefit for patients with pancreatic islet cell tumors with liver metastases.

Adenoma, Islet Cell↗
PubMed1997

Reorganization of a novel vimentin-associated protein in 3T3-L1 cells during adipose conversion.

We have found that the antibody A2, a marker for the capsule of steroidogenic lipid droplets, reacts with an intermediate filament-associated protein, P200, in 3T3-L1 preadipocytes. Supporting evidence came from the colocalization pattern of P200 with vimentin in double label experiments. The association of P200 with vimentin was further confirmed by its copurification with vimentin after high salt extraction and colocalization of these two proteins in high salt-extracted and vinblastine-treated cells. In preadipocytes this protein was distributed on the vimentin filament network. At the early stage of adipose conversion, this protein was found to encircle nascent lipid droplets ranging from 0.1 to 0.2 micron, accompanied with a decreased distribution on the vimentin filament system. This infers a possible translocation of P200 from the vimentin filaments to the droplet surface. Meanwhile, the vimentin filaments remained in a normal distribution in the cytoplasm and were apparently not associated with the nascent droplet. The association of vimentin filaments to droplet surfaces became prominent in lipid droplets larger than 0.2 micron, forming a typical vimentin cage. Immunogold staining also confirmed the translocation of P200 immunoreactivity from the droplet surface to the vimentin cage. The relocation of P200 from the cytoplasmic vimentin filaments to the droplet surface prior to the formation of the vimentin cage, as well as the reorganization of this protein in the vimentin cage, suggests a stabilizing role in the lipid droplet formation and an inducing function of this protein in the formation of the vimentin cage.

3T3 Cells↗
PubMed1997

D2 dopamine receptor polymorphism and brain regional glucose metabolism.

Positron emission tomography (PET) studies have shown decreased glucose metabolism in brain regions of detoxified alcoholics and cocaine abusers. However, it is not clear whether this decrease is due to chronic drug abuse or a pre-existing condition. Molecular genetic studies have found an association of the D2 dopamine receptor (DRD2) A1 allele with alcoholism and drug abuse. Moreover, reduced central dopaminergic function has been suggested in subjects who carry the A1 allele (A1+) compared with those who do not (A1-). In the present study, using 18F-deoxyglucose, regional glucose metabolism was determined in healthy nonalcohol/nondrug-abusing subjects with the A1+ or A1- allele. The mean relative glucose metabolic rate (GMR) was significantly lower in the A1+ than the A1- group in many brain regions, including the putamen, nucleus accumbens, frontal and temporal gyri and medial prefrontal, occipito-temporal and orbital cortices. Decreased relative GMR in the A1+ group was also found in Broca's area, anterior insula, hippocampus, and substantia nigra. A few brain areas, however, showed increased relative GMR in the A1+ group. Since polymorphism of the DRD2 gene is commonly observed in humans, the importance of differentiating A1+ and A1- alleles subjects in PET studies is suggested.

Adult↗
PubMed1997

Increased dopamine activity associated with stuttering.

Position emission tomography using 6-FDOPA as a marker of presynaptic dopaminergic activity was used to investigate the role of the dopamine system in stuttering. Three patients with moderate to severe developmental stuttering were compared with six normal controls. Stuttering subjects showed significantly higher 6-FDOPA uptake than normal controls in medial prefrontal cortex, deep orbital cortex, insular cortex, extended amygdala, auditory cortex and caudate tail. Elevated 6-FDOPA uptake in ventral limbic cortical and subcortical regions is compatible with the hypothesis that stuttering is associated with an overactive presynaptic dopamine system in brain regions that modulate verbalization.

Adult↗
PubMed1997

Rationally designed inhibitors of inosine monophosphate dehydrogenase.

Functionalized 2-alkyl derivatives of inosinic acid have been synthesized to serve as reversible as well as irreversible inhibitors of the human type II enzyme inosine monophosphate dehydrogenase. These compounds were designed to react with Cys-331 of the enzyme to form covalent bonds so as to interfere with the normal enzyme mechanism which involves attack of Cys-331 at C-2 of the substrate. Mass spectrometric analysis of the reaction products after enzymatic degradation confirmed the appropriateness of the inhibitor design.

Chromatography, High Pressure Liquid↗
PubMed1997

Differential effects of adenosine on antegrade and retrograde fast pathway conduction in atrioventricular nodal reentry.

Although adenosine depresses antegrade atrioventricular (AV) nodal conduction, the effects of adenosine on antegrade and retrograde fast pathway conduction in AV nodal reentry have not been determined. In 17 patients (five men, 12 women, mean age 49 +/- 12 years) with common slow-fast AV nodal reentrant tachycardia, the antegrade slow pathway conduction was selectively and completely ablated by radiofrequency catheter ablation while the antegrade and retrograde fast pathway conduction remained intact. During high right atrial pacing at a mean pacing cycle length of 474 +/- 36 msec, adenosine was rapidly injected intravenously at an initial dose of 0.5 mg followed by stepwise increases of 0.5 mg or 1.0 mg given at 5-minute intervals until second-degree AV block developed. During right ventricular apical pacing at the same pacing cycle lengths (mean 474 +/- 36 msec) as those in the study of antegrade conduction, intravenous injection of incremental doses of adenosine was repeated until ventriculoatrial (VA) block occurred. The adenosine-induced prolongation of VA conduction was also determined in the presence of verapamil (loading dose 0.15 mg/kg, maintenance dose 0.005 mg/kg/min) in seven of 17 patients. The dose of adenosine required to produce AV block, the increase in the atrio-His interval by 50% and the maximal response were 3.4 +/- 1.4 mg, 1.8 +/- 0.6 mg, and 58% +/- 5%, respectively. On the other hand, the dose of adenosine required to produce VA block, the increase in the VA interval by 50%, and the maximal response were 8.2 +/- 2.9 mg, 3.4 +/- 0.6 mg, and 20% +/- 5%, respectively, in the control and 3.7 +/- 0.5 mg, 3.5 +/- 0.7 mg, and 23% +/- 5%, respectively, in the presence of verapamil. In conclusion, adenosine has a differential potency to depress AV and VA conduction in patients with AV nodal reentry, with greater potency for slowing antegrade fast than retrograde fast pathway conduction. Verapamil had an additive effect to adenosine on slowing retrograde VA conduction, which further supports the evidence that the retrograde fast pathway in part involves an AV nodal-like structure.

Adenosine↗
PubMed1997

The role of hepatitis G virus infection in patients with acute posttransfusion hepatitis in Taiwan.

BACKGROUND & AIMS: Hepatitis G virus (HGV) has been recently identified as a new transfusion-transmissible agent. This study was performed to evaluate the role of HGV infection in patients with acute posttransfusion hepatitis in Taiwan. METHODS: Sera from 63 patients with acute posttransfusion hepatitis and 61 patients with normal serum aminotransferase levels after transfusion were tested for HGV RNA by reverse-transcription polymerase chain reaction. RESULTS: Six of the 63 patients (9.5%) with acute posttransfusion hepatitis were positive for HGV RNA in pretransfusion sera; 4 were superinfected with hepatitis C virus (HCV) after transfusion and 3 developed chronic hepatitis. Seven (12.3%) of the remaining 57 patients had acute posttransfusion HGV infection; 5 were coinfected with HCV and 2 infected with HGV alone. None with acute HGV infection alone developed chronic hepatitis, whereas 4 of 5 patients (80%) with acute HGV and HCV coinfection developed chronic hepatitis. The clinical course of acute HGV and HCV coinfection was similar to that of acute HCV infection alone. Four of 61 subjects (6.6%) with normal serum aminotransferase levels after transfusion were subclinically infected with HGV. CONCLUSIONS: HGV infection accounted for 12.3% of acute posttransfusion hepatitis in Taiwan before anti-HCV screening of blood donors. The clinical course of acute posttransfusion HGV infection alone was relatively benign.

Acute Disease↗
PubMed1997

Specific inhibition of delta antigen by in vitro system by antisense oligodeoxynucleotide: implications for translation mechanism and treatment.

Synthetic antisense oligodeoxynucleotides (ODNs) and a system containing transcription and translation coupled rabbit reticulocyte lysate were used to develop a new model modulating the synthesis of small delta antigen which, in turn, inhibits the replication of HDV (hepatitis D virus). The ODN was stable for at least 50 min in this system at 37 degrees C. Unmodified 15-mer antisense D3 and D4, complementary to translation initiation region and coding region, respectively, inhibit the synthesis of small delta antigen by 95% at a concentration of 5 microM, whereas antisenses complementary to 5' noncoding region, stop codon region and polyadenylation site were less effective. This system also showed a dose-dependent inhibitory effect of antisense D3 on the production of the target protein. However, the synthesis of E6 protein, an internal control, was not affected. These observations imply that this in vitro system is convenient for rapid screening of effective antisense compounds and offers a promising perspective for the investigation of translation mechanisms and for the inhibition of HDV replication by antisense strategy.

Animals↗
PubMed1997

Decreasing striatal 6-FDOPA uptake with increasing duration of cocaine withdrawal.

It has been hypothesized that a decrease in dopaminergic presynaptic activity during abstinence or withdrawal is related to relapse in cocaine-dependent subjects (Dackis and Gold 1985; Markou and Koob 1991). This study measured striatal 6-fluorodopa (6-FDOPA) uptake, an index of dopaminergic presynaptic activity, using positron emission tomography (PET) in 11 drug-free cocaine addicts compared to eight normal subjects. Middle abstinence cocaine addicts (n = 5, off cocaine 11-30 days) had significantly lower striatal 6-FDOPA uptake compared to normal controls or early abstinence cocaine addicts (n = 6, off cocaine 1-10 days). The cocaine-dependent subjects (n = 11) showed a significant negative correlation between days off cocaine and striatal 6-FDOPA uptake. The results suggest that during abstinence from cocaine there is a delayed decrease in dopamine terminal activity in the striatum.

Adult↗