Search PubMed⌕ Search

Biomedical subjects

W J Chen

Publications and source records attributed to W J Chen.

At least 19 recordsLinked to original sources
PubMed2000

Molecular characterization of myocardial fibrosis during hypothyroidism: evidence for negative regulation of the pro-alpha1(I) collagen gene expression by thyroid hormone receptor.

The purpose of this study was to gain insights into the underlying mechanism of myocardial fibrosis during hypothyroidism. Treatment of cardiac fibroblasts with a medium lacking thyroid hormone led to a 47% increase in [3H]thymidine incorporation into the cell nuclei compared with that in untreated cells. Northern blot analysis of RNA from cardiac fibroblasts grown in a thyroid hormone depleted medium resulted in a 38% increase in the abundance of mRNA for pro-alpha1(I) collagen. At the protein level, the amount of type I collagen, as determined by immunoprecipitation, was increased either in the cell lysate (46%) of cardiac fibroblasts grown in a thyroid hormone depleted medium or in the medium (44%). The chimeric plasmid, ColCAT 3.6, contains the 5'-flanking region of the rat pro-alphal(I) collagen gene (from bases -3520 to +115) fused to the chloramphenicol acetyltransferase (CAT) gene. The plasmid was cotransfected with thyroid hormone receptor (TR) expression plasmid into rat cardiac fibroblasts and COS-l cells (monkey mesangial cells). Cells transfected with the ColCAT plasmid in the presence of thyroid hormone (100 nM T(3)) had a significant decrease (39% in fibroblasts, P<0.01; 52% in COS-1 cells, P<0.001) in CAT activity when compared to cells not exposed to thyroid hormone. Transient co-transfection of TR with various pro-alphal(I) collagen/CAT deletion constructs showed that T(3)-dependent repression was preserved with the deletion from 3520 bp of the flanking sequence to a 5' end point at position -224, indicating that a thyroid hormone-response element (TRE) was localized at the region -224 to +115. The TR-DNA binding assays demonstrated binding of the human TRbeta1 to a fragment containing a proposed TRE located between position -35 and +115 in the 5'-flanking region of the rat pro-alphal(I) collagen gene.

Animals↗
PubMed2000

Accuracy of ultrasonography in the diagnosis of peritonitis compared with the clinical impression of the surgeon.

HYPOTHESIS: Peritonitis is a well-known indication for surgery, but its preoperative cause usually is not established. We hypothesize that abdominal ultrasonography is superior to the clinical impression of the surgeon in detecting the cause of peritonitis. DESIGN: A prospective case series. SETTING: A major university hospital in Taiwan, Republic of China. PATIENTS AND METHODS: One hundred two patients with a diagnosis of peritonitis admitted to the Department of Emergency Medicine, National Taiwan University Hospital, Taipei, were included in this study. All 102 patients underwent an abdominal ultrasonographic examination; and the ultrasonographic findings of these patients were classified into 2 categories: positive findings and normal screening results. The accuracy of clinical impression in detecting the cause of peritonitis was compared with the accuracy of abdominal ultrasonography. RESULTS: Ultrasonography and clinical impression accurately diagnosed the peritonitis in 85 (83.3%) and 52 (51.0%) of the patients, respectively. The difference between ultrasonography and clinical impression in the diagnosis of peritonitis was significant (P<.001). Among 45 patients without a preoperative clinical diagnosis, a diagnosis was made by ultrasonography for 32 (71%) of them. There were a total of 98 patients with positive ultrasonographic findings, and 4 patients had normal screening results. Of the 98 patients with positive ultrasonographic findings undergoing surgery, all had abdominal pathological characteristics. The 4 patients with normal screening results received nonoperative treatment. CONCLUSIONS: Ultrasonography is a more sensitive technique than clinical judgment in diagnosing peritonitis. Ultrasonography may be a useful diagnosing modality in patients with peritonitis in whom the clinical cause is unclear.

Clinical Competence↗
PubMed2000

Sustained attention deficits as markers of genetic susceptibility to schizophrenia.

This article reviews recent evidence regarding the potential of the visual sustained attention deficits as measured by the Continuous Performance Test (CPT) as an endophenotype of the genetic susceptibility to schizophrenia. Findings in community subjects indicate that sustained attention develops during the primary school ages, reaches its maximum around early adolescence, and declines with age after adulthood. The assertion that CPT performance deficits, and especially on the more difficult versions, are reliable and valid genetic susceptibility indicators of schizophrenia is supported by the following results: 1) CPT deficits are present in schizophrenic patients, are particularly associated with negative and disorganized symptoms, and deficits on the more difficult CPT versions are not amenable to neuroleptic treatment; 2) subjects with schizotypal personality features also exhibit CPT deficits, which are specifically associated with the negative factor of schizotypy; 3) a substantial proportion of nonpsychotic relatives of schizophrenic patients (19-34%) have CPT deficits, which can also be predicted from their probands' CPT performance. Thus, using a CPT deficits as an endophenotype of schizophrenia would not only provide a valuable measure of genetic risk, but would also greatly enhance our understanding of etiology, and may help identify susceptibility genes for schizophrenia.

Attention Deficit Disorder with Hyperactivity↗
PubMed2000

Anterior reconstructive spinal surgery with Zielke instrumentation for metastatic malignancies of the spine.

From March 1984 to April 1996, 60 consecutive patients with spinal metastasis underwent palliative surgery by anterior corpectomy and Zielke instrumentation. Their ages ranged from 21 to 76 years (mean 54 years). Thirty-two patients had metastasis to the thoracic spine, 20 to the lumbar spine, and 8 had both thoracic and lumbar metastases. The primary malignancies were lung cancer in 12 patients, colorectal cancer in 10, hepatoma in 9, thyroid cancer in 7, breast cancer in 3, and cancers of the stomach, kidney, nasopharynx, long bones, skin, and cervix in 1 patient each. A primary carcinoma was never identified in 13 patients. In the present series, 4 patients died within 1 month, and 56 patients were followed-up. All maintained spinal stability postoperatively. Forty of 52 patients with severe pain obtained significant symptomatic relief for 3 months or more, and 33 of the 46 paralyzed patients gained neural improvement. Sphincter dysfunction became better in 10 patients, and none became worse. We conclude that anterior corpectomy to decompress neural encroachment with instrumental reconstruction to stabilize the collapsed spine is a good adjunctive treatment in these highly selected patients.

Adult↗
PubMed2000

Free radical scavenging activity of fullerenol on the ischemia-reperfusion intestine in dogs.

Fullerenol, a water-soluble C(60)-fullerene derivative, has been demonstrated to have the capability to scavenge free radicals in vitro and in vivo. The purpose of this study was to investigate whether fullerenol can scavenge the free radicals that are massively induced during ischemia-reperfusion (I/R) injury of the small intestine, either preventively or therapeutically. Clamping the superior mesenteric artery and vein for 60 minutes to induce I/R injury was performed on male mongrel dogs. Thirty dogs were divided into three groups (10 in each): The control (C) group received no medication; the preventive (P) group received fullerenol (1 mg/kg) intravenously 30 minutes before ischemia; the therapeutic (T) group received the same dose of fullerenol immediately after reperfusion. This study was an experimental randomized trial. Intestinal segments were obtained 10, 20, 30, and 60 minutes after reperfusion; and blood samples and specimens of major organs were taken 60 minutes after reperfusion. Concentrations of lipid peroxidation products, including conjugated diene (CD) and malondialdehyde (MDA), and the level of glutathione (GSH) in intestinal tissue were determined. Serum indicators of liver and renal function were measured. Histologic examination of the small intestine and major organs were also performed. A significant increase in intestinal MDA and CD contents was detected at 30 and 60 minutes after reperfusion. The tissue GSH content, in contrast, was decreased 60 minutes after reperfusion. Administration of fullerenol diminished these changes both preventively and therapeutically. Liver and renal functions were within normal limits in all groups. Moreover no obvious histopathologic additional damage could be found in either the P or the T group. It is suggested that fullerenol can be considered a powerful scavenger for the free radicals induced by I/R injury of the small intestine.

Alanine Transaminase↗
PubMed2000

Reappraisal of the role of the bilioenteric conduit in the pathogenesis of postoperative cholangitis.

The incidence of postoperative cholangitis has changed very little despite progressive improvement in the treatment of biliary atresia. The role of the bilioenteric conduit in its pathogenesis is still uncertain. A retrospective study of 39 patients undergoing either a conventional Kasai operation (group 1, n = 20) or with placement of an antireflux valve (group 2, n = 10) or lengthening (group 3, n = 9) of the jejunal conduit from 40 to 60 cm was performed to compare the incidence of cholangitis. Postoperative cholangitis developed in 18 of the 39 patients (46%). The incidence was 10/20 (50%) in group 1, 5/10 (50%) in group 2, and 3/9 (33%) in group 3 (P = 0.679). An animal experiment was conducted concomitantly to compare quantitative bacterial cultures of the bilioenteric anastomosis and the liver before and 1 week after Roux-en-Y hepaticojejunostomy (HPJ) in piglets without (group A, 25 cm) and with (group B, 50 cm) lengthening of the jejunal conduit in a porcine model of extrahepatic biliary obstruction. The growth of bacteria in both the bilioenteric anastomosis and the liver was not affected by lengthening the jejunal conduit from 25 to 50 cm (P = 0.612 and 0. 057, respectively), despite a geometric increase in bacterial concentrations in both groups after HPJ. It is concluded that neither bacterial growth in the liver nor cholangitis following bile-duct reconstruction was affected by valving or lengthening the bilioenteric conduit.

Age Factors↗
PubMed2000

Tibial shaft malunion treated with reamed intramedullary nailing: a revised technique.

Thirty-seven consecutive adult tibial shaft malunions which had not undergone surgical treatment were prospectively treated with reamed intramedullary nailing. Indications for this treatment modality included a malunion of a tibial shaft which had only been conservatively treated, lesion level fitting for traditional or locked reamed intramedullary nail fixation, less than 2 cm shortening, and without evidence of deep infection at present. The malunions were treated with fibulotomy, closed wedge tibial osteotomy, open reaming of the marrow cavity, stable reamed intramedullary nail stabilization with or without supplementation, and cancellous bone grafting. Thirty-four (92%) patients were followed up for at least 1 year (range 1.0-4.3 years), and all achieved a solid union. The union period was 5.8+/-0.8 months. Complications included 2 (6%) patients with deep infection and 1 (3%) with cortical perforation. However, all 3 patients recovered completely after adequate management. In conclusion, a reamed intramedullary nail is an ideal instrument for tibial shaft malunions in indicated cases. Good exposure of the bony segments to ream the marrow cavity precisely can avoid cortical perforation. Gentle dissection of the soft tissues may lower the infection rate. Concomitant cancellous bone grafting can improve the union rate.

Adolescent↗
PubMed2000

Reactive pulmonary artery vasoconstriction in pulmonary consolidation evaluated by color Doppler ultrasonography.

A total of 122 patients with pulmonary consolidation on chest radiographs underwent color Doppler ultrasonography to evaluate hemodynamic change in regional pulmonary artery in pulmonary consolidation due to various causes. The diseases underlying pulmonary consolidation included 66 simple pneumonia, 37 obstructive pneumonia, 13 tumor consolidation and 6 pulmonary infarctions. Blood flow signals in consolidation were detected by color-flow mapping. The degree of reactive vasoconstriction was evaluated from analysis of the spectral waveform of the blood flow in the segmental pulmonary artery by several vessel resistance-indicating Doppler ultrasound (US) indices, including pulsativity index (PI), resistive index (RI), and acceleration time (AT). The results showed that reactive vasoconstriction was most marked in obstructive pneumonia, followed by simple pneumonia, and least in tumor consolidation (p < 0.001, Kruskal-Wallis test and p < 0.001, Dunn's test for comparison of PI, RI and AT values between different groups of pulmonary consolidation). No flow was detected in pulmonary infarction. We conclude that color Doppler US is a useful tool for evaluating reactive vasoconstriction in pulmonary consolidation. The different degrees of reactive vasoconstriction may be helpful in exploring the possible etiology of pulmonary consolidation.

Blood Flow Velocity↗
PubMed2000

Effects of atypical neuroleptics on sustained attention deficits in schizophrenia: a trial of risperidone versus haloperidol.

To help determine whether sustained attention deficits as measured with the Continuous Performance Test (CPT) are stable vulnerability indicators of schizophrenia, we compared the CPT performance of schizophrenic patients before and after treatment with risperidone or haloperidol. In this double blind trial, 56 schizophrenic patients were randomly assigned to a 12-week regimen of either risperidone or haloperidol, after a 1-week washout period. The patients undertook two sessions of the CPT (undegraded and 25% degraded) twice, one at the end of the washout period and the other at the end of the study. Thirty-eight patients completed the study, 19 in each group. Both groups experienced significant improvements in clinical symptoms, and the risperidone group showed no change in the severity of extrapyramidal symptoms. Despite those improvements, the CPT performance indexes did not change significantly from the beginning to the end of the study. These findings indicate that sustained attention deficits might be stable vulnerability indicators of schizophrenia.

Adult↗
PubMed2000

Effects of parenteral infusion with fish-oil or safflower-oil emulsion on hepatic lipids, plasma amino acids, and inflammatory mediators in septic rats.

This study was designed to investigate the effects of preinfusion with total parenteral nutrition (TPN) using fish-oil (FO) versus safflower-oil (SO) emulsion as fat sources on hepatic lipids, plasma amino-acid profiles, and inflammatory-related mediators in septic rats. Normal rats, with internal jugular catheters, were assigned to two different groups and received TPN. TPN provided 300 kcal. kg(-1). d(-1), with 40% of the non-protein energy as fat. All TPN solutions were isonitrogenous and identical in nutrient composition except for the fat emulsion, which was made of SO or FO. After receiving TPN for 6 d, each group of rats was further divided into control and sepsis subgroups. Sepsis was induced by cecal ligation and puncture; control rats received sham operation. All rats were classified into four groups as follows: FO control group (FOC; n = 7), FO sepsis group (FOS; n = 8), SO control group (SOC; n = 8), and SO sepsis group (SOS; n = 9). The results of the study demonstrated that plasma concentrations of triacylglycerol and non-esterified fatty acids did not differ between the FO and SO groups, regardless of whether the animals were septic. SOS had significantly higher total lipids and cholesterol content in the liver than did the SOC group. The FOS group, however, showed no difference from the FOC group. Plasma leucine and isoleucine levels were significantly lower in the SOS group than in the SOC group, whereas no difference in these two amino acids was observed between the FOC and FOS groups. Plasma arginine levels were significantly lower in both septic groups than in the groups without sepsis when either FO or SO was infused. Plasma glutamine levels, however, did not differ across groups. No differences in interleukin-1beta, interleukin-6, tumor necrosis factor-alpha, or leukotriene B(4) concentrations in peritoneal lavage fluid were observed between the two septic groups. These results suggest that catabolic reaction in septic rats preinfused with FO is not as obvious as those preinfused with SO. Compared with SO emulsion, TPN with FO emulsion prevents liver fat accumulation associated with sepsis. However, parenterally administered FO had no beneficial effect in lowering cytokines and LTB(4) levels in peritoneal lavage fluid in septic rats induced by cecal ligation and puncture.

Amino Acids↗
PubMed2000

Water-soluble Hexasulfobutyl[60]fullerene inhibit low-density lipoprotein oxidation in aqueous and lipophilic phases.

Oxidative modification of low-density lipoprotein (LDL) plays a pivotal role in the pathogenesis of atherosclerosis. Increasing the resistance of LDL to oxidation may therefore mitigate, or even prevent, atherosclerosis. A new water-soluble C60 derivative, hexasulfobutyl[60]fullerene [C60 - (CH2CH2CH2CH2-SO3Na)6; FC4S], consisting of 6 sulfobutyl moieties covalently bound onto the C60 cage is a potent free radical scavenger. This study explored the antioxidative effect of sulfobutylated fullerene derivatives (FC4S) on LDL oxidation. FC4S was found to be effective in protecting LDL against oxidation induced by either Cu2+ or azo peroxyl radicals generated initially in the aqueous or lipophilic phase, respectively. Levels of the oxidative products, conjugated diene and thiobarbituric acid-reactive substances, and the relative electrophoresis mobility of the LDL were decreased. The addition of 20 microM FC4S at the early stage of oxidation increased the kinetic lag time from 69 +/- 11 to 14 +/- 10 min (P < 0.05) and decreased the propagation rate from 17.1 +/- 2.6 to 6.3 +/- 1.0 mOD/min (P < 0. 005). Persistent suppression of peroxidation reaction was observed upon further addition of FC4S after full consumption of all endogenous antioxidants during the propagation period. Intravenous injection of hypercholesterolemic rabbits with FC4S (1 mg/kg/day) efficiently decreased atheroma formation. Data substantiate the use of FC4S as an excellent hydrophilic antioxidant in protecting atheroma formation, via removing free radicals, in either aqueous or lipophilic phase.

Animals↗
PubMed2000

Performance on the Wisconsin Card Sorting Test among adolescents in Taiwan: norms, factorial structure, and relation to schizotypy.

The aims of this study were to assess developmental trends in performance on the Wisconsin Card Sorting Test (WCST) among 817 randomly selected adolescents aged 13-15 years, and to explore WCST performance factor structure and relationship to schizotypy. The results showed that of the nine WCST indexes, only the Categories Achieved and Failure to Maintain Set scores were associated with age, and only the Learning to Learn scores reached adult levels. Factor analysis of WCST performance scores yielded a three-factor structure. Psychometrically defined schizotypic subjects did not perform significantly worse than control subjects on any WCST indexes. These findings suggest that performance on various WCST indexes might indicate developmental changes at different ages, and deficits in WCST performance might not be sensitive indicators of vulnerability to schizophrenia in adolescence.

Adolescent↗
PubMed2000

Competence and behavioral/emotional problems among Taiwanese adolescents as reported by parents and teachers.

OBJECTIVE: To investigate competence and behavioral/emotional problems among nonreferred adolescents in Taiwan, using a Chinese version of the Child Behavior Checklist (CBCL-C) and the Teacher's Report Form (TRF-C). The psychometric properties of these instruments and cross-cultural differences were also examined. METHOD: Parents of 854 junior high school students aged 12 to 16 years in Taipei, Taiwan, were asked to complete the CBCL-C. Among these students, 162 had their teachers' ratings of the TRF-C. RESULTS: The internal consistency and 1-month test-retest reliability were satisfactory for both the CBCL-C and TRF-C, which were moderately correlated. Both exploratory and confirmatory factor analysis provided some support for the validity of Achenbach's cross-informant model. Parents' reports showed that compared with their American counterparts, Taiwanese adolescents tended to have lower scores on most competence scales, higher scores on scales that reflect covert behavior problems, and lower scores on scales that reflect more overt behavior problems. However, teachers' reports showed no significant differences on most competence and behavior problem scales. CONCLUSION: The CBCL-C and TRF-C are useful tools for assessing the mental health status of Taiwanese adolescents. The cross-cultural differences in adolescent behavior problems are discussed.

Achievement↗
PubMed2000

Use of constitutive G protein-coupled receptor activity for drug discovery.

This article describes the behavior of transiently transfected human receptors into melanophores and the potential use of constitutive receptor activity to screen for new drug entities. Specifically, transient transfection of melanophores with different concentrations of receptor cDNA presumably leads to increased levels of receptor expression. This leads to an increased response to agonists (both maxima and potency) and, in some cases, an agonist-independent constitutive receptor activity. Transfections with increasing concentrations of the G(s) protein-coupled human calcitonin receptor type 2 (hCTR2) cDNA produced sufficient levels of constitutively activated receptor to cause elevated basal cellular responses. This was observed as a decrease in the transmittance of light through melanophores (consistent with G(s) protein activation) and increased response to human calcitonin. The receptor-mediated nature of this response was confirmed by its reversal with the hCTR2 peptide inverse agonist AC512. A collection of ligands for hCTR2 either increased or decreased constitutive hCTR2 activity, suggesting that the constitutive system was a sensitive discriminator of positive and negative ligand efficacy. Similar results were obtained with G(i)-protein-coupled receptors. Transient transfection of NPY1, NPY2, NPY4, CXCR4, and CCR5 cDNA produced increased light transmittance through melanophores (consistent with G(i)-protein activation). NPY1 cDNA produced little constitutive response on transfection, whereas maximal levels of constitutive activity ranging from 30 to 45% were observed for the other G(i)-protein-coupled receptors. Responses to agonists for these receptors increased (both maxima and potency) with increasing cDNA transfection. The receptor/G(i)-protein nature of both the constitutive and agonist-mediated responses was confirmed by elimination with pertussis toxin pretreatment. These data are discussed in terms of the theoretical aspects of constitutive receptor activity and the applicability of this approach for the general screening of G protein-coupled orphan receptors.

Amino Acid Sequence↗
PubMed2000

Sinus node dysfunction in a patient with lithium intoxication.

Lithium can suppress sinus node function, especially when it is used concomitantly with carbamazepine. We describe a 42-year-old woman who took lithium and carbamazepine for manic-depressive psychosis and seizure disorders, and developed marked sinus node dysfunction. Drug screening showed a toxic serum lithium level of 3.38 mmol/L and a normal serum carbamazepine level of 22.1 mumol/L. An electrophysiologic study showed prolongation of the corrected sinus node recovery time (CSNRT) of up to 9,708 msec. After three sessions of hemodialysis, normal sinus rhythm was resumed. The serum lithium level was 0.1 mmol/L 2 weeks later, and the CSNRT shortened to 309 msec. Because the combination of lithium and carbamazepine in psychiatric patients is not uncommon, recognition of the potential complication of severe bradyarrhythmia is essential in the emergency care of such patients.

Adult↗