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Biomedical subjects

H M Chen

Publications and source records attributed to H M Chen.

At least 37 records · Page 2Linked to original sources
PubMed2001

Association between genetic polymorphism of tumor necrosis factor-alpha and risk of oral submucous fibrosis, a pre-cancerous condition of oral cancer.

Many cytokines have been thought to play important roles in the pathogenesis of oral submucous fibrosis (OSF), an areca nut chewing-specific pre-cancerous condition characterized by the deposition of collagen in oral submucosa. Tumor necrosis factor-alpha (TNF-alpha), situated in the class III region of human leukocyte antigen (HLA), is a mediator with multiple functions, including the regulation of inflammatory reaction and transcriptions of collagen and collagenase. In total, 809 male subjects were recruited for assessment of the association of OSF with a bi-allelic promoter-region (-308) polymorphism on the TNFA gene. The high production allele, TNF2, was significantly lower among OSF subjects (n = 166) than in areca-chewing controls (n = 284). This association was independent of oral cancer status. The multivariate-adjusted odds ratio for the TNFA 11 genotype was 2.6 (95% confidence interval = 1.4-4.9; p = 0.004). The finding may imply a multifunctional etiological factor of TNF-alpha in OSF pathogenesis.

Adult↗
PubMed2001

Cross-cultural implementation of a Chinese version of the Schedules for Clinical Assessment in Neuropsychiatry (SCAN) in Taiwan.

BACKGROUND: There are no published reports of cross-cultural equivalence and interrater reliability at the level of individual symptom items assessed by a semi-structured clinical interview employing operationalised clinician ratings. AIMS: To assess the cross-cultural clinical equivalence and reliability of a Chinese version of the World Health Organization Schedules for Clinical Assessment in Neuropsychiatry (SCAN). METHOD: UK-US and Taiwanese groups of psychiatrists used Chinese and English transcripts of videotape interviews of Taiwanese patients to discuss cross-cultural issues and ratings of SCAN items. Item ratings were compared quantitatively individually and pooled by SCAN section. RESULTS: Chinese equivalents were found for all SCAN items. No between-group differences were found for most individual items, but there were differences for some scaled items. Average agreement between the two groups was 69-100%. CONCLUSIONS: Cross-cultural implementation based on SCAN in Taiwan appears valid.

China↗
PubMed2001

Regulation of steroidogenic acute regulatory protein expression and progesterone production in endometriotic stromal cells.

The regulation of steroidogenic acute regulatory protein (StAR) gene expression and the synthesis of steroids from cholesterol in ectopic endometriosis tissues were investigated. Peritoneal fluid and endometrial tissues were collected from patients with endometriosis and otherwise healthy women. Peritoneal progesterone and 17 beta-E2 concentrations were highest in early stage endometriosis compared with those in advanced stage endometriosis and in normal women. In concordance with the profile of peritoneal steroids, StAR mRNA and protein were greatest in ectopic implants of early endometriosis. In the advanced stage, concentrations of StAR mRNA and protein were also greater compared with those in normal endometrium. In contrast, P450 side-chain cleavage enzyme and 3 beta-hydroxysteroid dehydrogenase transcripts were not different between normal endometrium and ectopic endometriotic implants. Expression of StAR mRNA was detected in purified stromal, but not epithelial, cells. Treatment with PGE(2), but not TNF alpha, or IL-1 beta significantly increased StAR expression and thus induced progesterone production in cultured endometriotic stromal cells. These results demonstrated that aberrant expression of StAR in ectopic endometriotic tissues leading to increased peritoneal progesterone is associated with the formation of endometriosis. Induction of StAR gene expression by peritoneal PGE(2) in endometriotic stromal cells may further contribute to the development of endometriosis.

Ascitic Fluid↗
PubMed2001

Intractable ventricular tachycardia in a patient with left ventricular epicardial lipoma.

Primary cardiac lipomas are rare and are often reported as incidental findings during operations or autopsies. Lipoma-induced arrhythmia, especially ventricular tachycardia (VT), is an unusual complication of primary cardiac lipoma. We describe the case of a 43-year-old woman who presented with VT without any cardiac abnormality except for a left ventricular tumor. Electrophysiologic study (EPS) failed to detect the origin of the arrhythmia, although VT could be induced by EPS preoperatively. Due to suspicion of a relationship between the tumor and the VT, wide tumor resection was performed using cardiopulmonary bypass support. The excised lipoma measured about 10 x 8 x 3 cm and weighed 120 g, and was without pathohistologic evidence of malignant change. The patient was well without further postoperative need for antiarrhythmic drugs at 36 months' follow-up, and VT was no longer inducible on subsequent EPS mappings.

Adult↗
PubMed2001

Interaction of Cd and citric acid, EDTA in red soil.

Adsorption and desorption process of cadmium in red soil (Ferrisols) as well as the influence by media's pH were investigated in detail with and without citric acid and EDTA. Experimental results clearly showed that Cd adsorption in red soil was affected significantly by the coexisted organic chemicals. In the presence of citric acid and EDTA, Cd adsorption in red soil increased with pH in acid media but decreased in high pH one. Further studies placed stress on the adsorbed Cd in red soil which was found to be existed mainly as exchangeable one at pH < 5.5, and desorption rate by 0.10 mol/L NaNO3 gave a peak-shaped curve due to the difference of specifically and nonspecifically adsorbed Cd with pH's change.

Adsorption↗
PubMed2001

Groove pancreatitis: case report and literature review.

Groove pancreatitis is a form of chronic pancreatitis affecting the groove between the head of the pancreas, the duodenum and the common bile duct. It was first described by Becker in 1973. Differentiation between groove pancreatitis and pancreatic head carcinoma is often difficult. Herein, we report a 24-year-old man with groove pancreatitis presenting with epigastralgia, jaundice, fever and vomiting. The diagnosis was confirmed by computed tomography of the abdomen, endoscopic retrograde cholangiopancreatography and surgical exploration. The operative procedures involved were pancreatic biopsy and choledochotomy with T-tube drainage. The patient had an uneventful postoperative course.

Adult↗
PubMed2000

Cleavage of lamin-like proteins in in vivo and in vitro apoptosis of tobacco protoplasts induced by heat shock.

Apoptosis in heat shock-treated tobacco protoplasts was evidenced by DNA fragmentation, flow cytometric analysis and activation of caspase 3-like protease. Furthermore, an in vitro apoptosis system was established which reproduced the apoptotic events. Western blotting analysis using an antibody against lamin A and C showed that in both in vivo and in vitro systems lamin-like proteins were cleaved into a 35-kDa fragment, and that lamin-like protein degradation precedes DNA fragmentation. Moreover, we found a 22.8-fold increase in caspase 6-like activity in cytosol of heat-treated protoplasts as compared with the control.

Apoptosis↗
PubMed2000

Conformational study of a custom antibacterial peptide cecropin B1: implications of the lytic activity.

Cecropin B1 (CB1) with two amphipathic alpha-helical segments is a derivative of the natural antibacterial peptide, cecropin B. The assays of cell lysis show that, compared with cecropin A (CA), CB1 has a similar ability to lyse bacteria with a higher potency (two- to six-fold higher) in killing cancer cells. The difference may be due to the fact that the peptides possess different structures and sequences. In this study, the solution structure of CB1 in 20% hexafluoroisopropanol was determined by two-dimensional nuclear magnetic resonance (NMR) spectroscopy. The (1)H NMR resonances were assigned. A total of 350 inter-proton distances were used to calculate the solution structure of CB1. The final ensemble structures were well converged, showing the minimum root mean square deviation. The results indicate that CB1 has two stretches of helices spanning from residues 3 to 22 and from residues 26 to 33, which are connected by a hinge section formed by Gly-23 and Pro-24. Lys-25 is partially incorporated in the hinge region. The bent angle between two helical segments located in two planes was between 100 and 110 degrees. With comparisons of the known NMR structure of CA and its activities on bacteria and cancer cells, the structure-function relationship of the peptides is discussed.

Amino Acid Sequence↗
PubMed2000

Concomitant management of airway and its adjacent vascular pathology in addition to repair of congenital cardiac defects.

Respiratory symptoms are often present in infants with congenital cardiac anomalies, but the intrinsic pathology of the airway itself or external compression by abnormal vessels is frequently undetected before cardiac repair. We collected 12 patients with airway pathology from July 1996 to October 1998; all had definite diagnosis of lesions of the airway and its adjacent vessels by preoperative ultrafast computed tomography. Four had intrinsic pathology (one retrotracheal diverticulum, three tracheal stenosis) as well as external compression. Among them, six had complete vascular ring, four partial rings and three had bronchial compression by aneurysmal dilatation of branch pulmonary arteries. Simultaneous airway repair (one diverticulectomy, three patch tracheoplasty) and external decompression were performed in ten cases under cardiopulmonary bypass, nine of ten had simultaneous cardiac repair; the other two were done before cardiac repair. All survived except three. We concluded that ultrafast computed tomography is indispensable for definite diagnosis of airway and adjacent cardiovascular pathology. Mere repair of congenital cardiac defects without rectification of the airway and its adjacent structures is incompatible with survival.

Aorta↗
PubMed2000

Perceptual differences between stroke patients with cerebral infarction and intracerebral hemorrhage.

OBJECTIVE: To assess perceptual performances of patients with intracerebral hemorrhage (ICH) compared with those of ischemic patients early after stroke and to analyze the psychometric properties of three perceptual tests used in the study. DESIGN: Cross-sectional study. SETTING: A rehabilitation unit at a teaching hospital. PATIENTS: Twenty-two stroke patients with ICH and 22 demographically matched stroke patients with infarction. MAIN OUTCOME MEASURES: Loewenstein Occupational Therapy Cognitive Assessment (LOTCA), Rivermead Perceptual Assessment Battery (RPAB), and Motor-Free Visual Perception Test (MVPT). RESULTS: Stroke patients with ICH had significantly more severe deficits on a task of thinking operations than did patients with infarction. A significant lateralized effect of stroke existed in the ICH group, with patients with right-hemisphere strokes scoring lower than patients with left-hemisphere strokes on the figure-ground discrimination subtest of the RPAB. A considerable overlap among the three instruments was found. Yet, the observed correlations between supposedly similar subtests from the tests proved to be moderate, indicating that to a certain extent these test measures tap different perceptual processes. Four factors were generated from a joint LOTCA-RPAB-MVPT factor analysis. They assessed different facets of perceptual functioning, including higher-level and lower-level perceptual skills, part/whole conceptual integration, and color perception. This factor pattern accounted for 75.5% of the variance. CONCLUSIONS: Higher-level perceptual functions tend to be relatively susceptible to ICH stroke pathology early in the course of the disease. This information has important clinical implications in the early treatment planning for the stroke patients with ICH, such that specific compensatory strategies for these deficiencies should be devised to facilitate a successful rehabilitation. Knowledge regarding the influences of specific deficits on the performance of daily activities may also be useful to the patients' family.

Adult↗
PubMed2000

Effect of applying chemical fertilizers on forms of lead and cadmium in red soil.

A three-month incubation study was undertaken to examine the influence of N, P and K on the various forms (soluble plus exchangeable (SE), weakly specifically adsorbed (WSA), Fe-Mn oxides bound (OX), organic matter complexed (OM) and residual fractions (RES)) of lead (Pb) and cadmium (Cd) in a red soil. Application of urea at the rate of 200 mg N/kg significantly lowered the SE fraction, but raised the WSA or OX fraction of both metals. Supply of 80 mg P/kg caused a decrease in the SE fraction of the two metals. The WSA fraction of Pb was reduced, whereas that of Cd increased by adding P. However, addition of 100 mg K/kg led to an increase in the SE fraction, but a decrease in the WSA fraction of Pb and Cd. Applying chemical fertilizers had no significant consistent influences on the other fractions of metals. These findings suggest that in heavy metal contaminated red soil, applying fertilizers does not only provide plant nutrients, but may also change the speciations and thus biovailability of heavy metals.

Agriculture↗
PubMed2000

Chemical methods and phytoremediation of soil contaminated with heavy metals.

The effects of chemical amendments (calcium carbonate (CC), steel sludge (SS) and furnace slag (FS)) on the growth and uptake of cadmium (Cd) by wetland rice, Chinese cabbage and wheat grown in a red soil contaminated with Cd were investigated using a pot experiment. The phytoremediation of heavy metal contaminated soil with vetiver grass was also studied in a field plot experiment. Results showed that treatments with CC, SS and FS decreased Cd uptake by wetland rice, Chinese cabbage and wheat by 23-95% compared with the unamended control. Among the three amendments, FS was the most efficient at suppressing Cd uptake by the plants, probably due to its higher content of available silicon (Si). The concentrations of zinc (Zn), lead (Pb) and Cd in the shoots of vetiver grass were 42-67%, 500-1200% and 120-260% higher in contaminated plots than in control, respectively. Cadmium accumulation by vetiver shoots was 218 g Cd/ha at a soil Cd concentration of 0.33 mg Cd/kg. It is suggested that heavy metal-contaminated soil could be remediated with a combination of chemical treatments and plants.

Calcium Carbonate↗
PubMed2000

Determination of interactions between human thrombopoietin and its receptor MPL by yeast two-hybrid system and affinity biosensor.

The binding of human thrombopoietin to the extracellular domain of its receptor MPL prompts a cascade transduction of intracellular signals, leading to the development of megakaryocyte precursors and the production of circulating platelets. We have used a yeast two-hybrid system to reveal, via in vivo interactions between different deletion constructs of MPL and thrombopoietin, that the extracellular subunit 1 of MPL is the ligand binding site and the N-terminal domain of thrombopoietin alone is sufficient for the binding. The extracellular portion of MPL was heterologously expressed in E. coli and its specific affinity with thrombopoietin was visualized in vitro by resonance mirror biosensor technique.

Binding Sites↗
PubMed2000

AZU-1: a candidate breast tumor suppressor and biomarker for tumor progression.

To identify genes misregulated in the final stages of breast carcinogenesis, we performed differential display to compare the gene expression patterns of the human tumorigenic mammary epithelial cells, HMT-3522-T4-2, with those of their immediate premalignant progenitors, HMT-3522-S2. We identified a novel gene, called anti-zuai-1 (AZU-1), that was abundantly expressed in non- and premalignant cells and tissues but was appreciably reduced in breast tumor cell types and in primary tumors. The AZU-1 gene encodes an acidic 571-amino-acid protein containing at least two structurally distinct domains with potential protein-binding functions: an N-terminal serine and proline-rich domain with a predicted immunoglobulin-like fold and a C-terminal coiled-coil domain. In HMT-3522 cells, the bulk of AZU-1 protein resided in a detergent-extractable cytoplasmic pool and was present at much lower levels in tumorigenic T4-2 cells than in their nonmalignant counterparts. Reversion of the tumorigenic phenotype of T4-2 cells, by means described previously, was accompanied by the up-regulation of AZU-1. In addition, reexpression of AZU-1 in T4-2 cells, using viral vectors, was sufficient to reduce their malignant phenotype substantially, both in culture and in vivo. These results indicate that AZU-1 is a candidate breast tumor suppressor that may exert its effects by promoting correct tissue morphogenesis.

Amino Acid Sequence↗
PubMed2000

Effects of timing of diatrizoate (water-soluble contrast medium) administration on pancreatic microcirculatory derangement in cerulein pancreatitis in rats.

OBJECTIVE: We investigated whether the timing of administration of contrast medium after onset of acute pancreatitis is critical in determining the magnitude of microcirculatory derangement. METHODS: An acute pancreatitis model in male Sprague-Dawley rats (225-275 g) was established by continuous infusion of cerulein (15 mg/kg per hour). The mean arterial pressure was monitored continuously by means of a femoral artery catheter. Diatrizoate (Hypaque-76), a water-soluble contrast medium, was delivered through a femoral vein catheter at doses corresponding to those given to humans, either 1, 2, or 3 hours after pancreatitis induction. In vivo microscopy and laser-Doppler flowmetry were used to investigate microcirculatory derangement. The water contents of the pancreas and lung, the malondialdehyde levels of the pancreas, and the trypsinogen activation peptide levels in the serum were measured at the end of the experiment (8 hours after infusion of cerulein). RESULTS: Early administration of contrast medium (1 hour after pancreatitis induction) resulted in significantly greater changes in microcirculation and mean arterial pressure than did late administration (2 or 3 hours after pancreatitis induction). Rats given contrast medium 1 hour after induction also had highest pancreas and lung water contents, the highest pancreas malondialdehyde levels, and the highest serum trypsinogen activation peptide levels. CONCLUSION: These results show that a water soluble contrast medium that is often used for computed tomographic imaging of the pancreas can adversely affect the pancreatic microcirculatory parameters, such as tissue perfusion and leukocyte sticking, and hemodynamics in a cerulein-induced model of acute pancreatitis. Early administration seems to cause more severe derangement of the pancreatic microcirculation.

Acute Disease↗
PubMed2000

Persistent fifth aortic arch: an ignored and underestimated disease.

We report two unique cases of persistent fifth aortic arch with a systemic-to-pulmonary connection. All previously reported cases with such a connection in the literature have either been cases of pulmonary atresia or an aortic arch anomaly, and the existence of a fifth aortic arch was a benefit to the underlying great vessel anomaly. However, our two cases did not have this associated great vessel anomaly, and the fifth arch resulted in a large left-to-right shunt with severe pulmonary hypertension and heart failure. The first case was misdiagnosed preoperatively; an accurate diagnosis was made after cardiac surgery. Because of its rarity and complexity, a persistent fifth aortic arch is often ignored and misdiagnosed.

Aorta↗
PubMed2000

Arcobacter butzleri bacteremia in a patient with liver cirrhosis.

Invasive Arcobacter butzleri infection in humans has been rarely described. We report a 60-year-old man with liver cirrhosis who presented with high fever and esophageal variceal bleeding. Two aerobic blood cultures grew Campylobacter-like organisms. The biochemical reactions of the isolate were inconclusive, while sequence analysis of the 16S rRNA gene definitively identified the organism as A. butzleri. The patient's bleeding stopped after endoscopic sclerosing therapy. Although the organism appeared to be resistant to cephalosporins on the basis of the minimum inhibitory concentrations determined with the E test, the fever resolved with parenteral cefuroxime. Whether the clinical improvement was related to cephalosporin therapy or to the self-limited nature of Arcobacter bacteremia is not known.

Arcobacter↗