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Biomedical subjects

W S Chen

Publications and source records attributed to W S Chen.

At least 19 recordsLinked to original sources
PubMed2003

Tuberculous wrist in the era of effective chemotherapy: an eleven-year experience.

BACKGROUND: The chronic course and non-specific clinical manifestations of tuberculous (TB) wrist often cause failure to make a timely diagnosis. OBJECTIVE: To better understand the rarely encountered TB wrist. PATIENTS AND METHODS: Retrospective review and analysis of cases of TB wrist between 1986 and 1997 in a medical centre in southern Taiwan. RESULTS: Thirty-seven cases (16 definitive, 13 probable and eight possible) of TB wrist (25 men, 12 women; mean age, 56.3 +/- 13.0 years) were found among a total of 4970 cases of tuberculosis. The most common presenting sign and symptom (mean duration 9.4 months) were local swelling and pain over the affected wrist. The mean white blood cell (WBC) count in peripheral blood was 7.04 x 10(9)/l, and the erythrocyte sediment rates (ESR) in seven of 31 patients who had ESR assayed were normal. Forty-six per cent of the patients had abnormal chest X-ray, and 35% had had previous manipulation of the affected wrist. CONCLUSION: Physicians should have a high index of suspicion for TB wrist among patients with chronic arthritis, even when their peripheral WBC count and ESR are normal. An abnormal chest X-ray and/or a history of previous manipulation of the affected wrist could be important clues for possible TB wrist.

Adult↗
PubMed2001

Growth retardation and increased apoptosis in mice with homozygous disruption of the Akt1 gene.

The serine/threonine kinase Akt has been implicated in the control of cell survival and metabolism. Here we report the disruption of the most ubiquitously expressed member of the akt family of genes, akt1, in the mouse. Akt1(-/-) mice are viable but smaller when compared to wild-type littermates. In addition, the life span of Akt1(-/-) mice, upon exposure to genotoxic stress, is shorter. However, Akt1(-/-) mice do not display a diabetic phenotype. Increased spontaneous apoptosis in testes, and attenuation of spermatogenesis is observed in Akt1(-/-) male mice. Increased spontaneous apoptosis is also observed in the thymi of Akt1(-/-) mice, and Akt1(-/-) thymocytes are more sensitive to apoptosis induced by gamma-irradiation and dexamethasone. Finally, Akt1(-/-) mouse embryo fibroblasts (MEFs) are more susceptible to apoptosis induced by TNF, anti-Fas, UV irradiation, and serum withdrawal.

Alleles↗
PubMed2001

Tumor invasiveness and liver metastasis of colon cancer cells correlated with cyclooxygenase-2 (COX-2) expression and inhibited by a COX-2-selective inhibitor, etodolac.

Non-steroidal anti-inflammatory drugs (NSAIDs) have been reported to reduce the risk and mortality of colorectal cancer (CRC). Although the exact mechanisms remain unclear, the inhibition of cyclooxygenase (COX) by NSAIDs appears to abort, if not prevent, CRC carcinogenesis or metastatic tumor progression. The aim of our study was to investigate the association between COX-2 expression and CRC tumor cell invasiveness. The differences in immunoblot-detectable COX-2 protein contents in primary CRCs, metastatic hepatic lesions and corresponding normal mucosa from the same individual were evaluated in 17 patients. Three different colon cancer cell lines, SW620, Lovo, HT-29 and a metastatic variant of HT-29, HT-29/Inv3, were employed to evaluate COX-2 expression and prostaglandin E(2) (PGE2) production in relation to their invasive abilities in vitro. The effects of a COX-2-selective inhibitor, etodolac, on cell proliferation and invasive activity were also determined. The results showed that 15 of 17 (88%) metastatic CRC cells from the liver and 14 of 17 (82%) primary CRC tissue exhibited much higher levels of COX-2 than corresponding adjacent normal mucosa from the same patient. Among those patients with relatively high COX-2 expression in the primary tumors, almost all exhibited even higher levels of COX-2 in their hepatic metastases. Among the 4 colon cancer cell lines, HT-29/Inv3 manifested the highest COX-2 expression, PGE2 production and in vitro invasive activity. The selective COX-2 inhibitor, etodolac, could especially exert cytotoxicity and markedly suppress the invasive property and PGE(2) production, although not the COX-2 protein level, in HT-29/Inv3 cells. Our results imply that COX-2 expression may be associated with the invasive and metastatic properties of CRC tumor cells.

Aged↗
PubMed2001

Carcinoembryonic antigen in monitoring of response to systemic chemotherapy in patients with metastatic colorectal cancer.

The response to chemotherapy of solid tumors is generally assessed by measuring tumors visualized by imaging. However, the response assessment based on imaging is not always feasible because patients often have disease not measurable by imaging, such as diffuse peritoneal dissemination. We evaluated the correlation between the change on imaging and change in CEA levels for assessing chemotherapeutic response of patients with metastatic colorectal cancer. Between July 1993 and August 1999 we retrospectively examined 136 patients with metastatic colorectal carcinoma, all of whom had measurable lesions. Forty patients received oral tegafur-uracil (300 mg/m2/day) plus folinic acid (60 mg/day) for 4 weeks, repeated every 5 weeks, as the firstline treatment. Another 96 patients received either a weekly intravenous bolus injection of 5-fluorouracil (400 mg/m2) plus folinic acid (20 mg/m2), or an intravenous bolus injection of 5-fluorouracil (425 mg/m2) plus folinic acid (20 mg/m2) for 5 consecutive days every month. Responders, based on CEA assessment, were defined as those with a greater than 50% drop in CEA level for more than 4 weeks. The pretreatment CEA levels were elevated beyond the normal cutoff value in 110 (81%) patients. A response rate of 18.4% (95% CI, 11.9-24.9%), including 8 complete remissions and 17 partial remissions, was achieved according to imaging studies. The response rate assessed by CEA was 25% (34/136). Sixteen responders (47%) based on CEA had no remission on imaging. The sensitivity of change in CEA levels in the prediction of true responders and progressive diseases on imaging were 72% and 81%, respectively. In terms of the positive predictive value, change in CEA levels in the prediction of true responders and progressive disease on imaging were 53% and 85%, respectively. Patients with remarkable falls on CEA levels survived significantly longer than nonresponders (P < 0.001, log-rank test). At follow-up of 48 months the median survival for responders and nonresponders assessed by CEA was 28 months and 13 months, respectively. These data suggest that measurement of CEA levels might be helpful in monitoring chemotherapeutic response when imaging study is unsuitable for assessing the response in clinical practice. Furthermore, measurement of CEA levels may be helpful in determining the prognosis of patients with metastatic colorectal cancer receiving chemotherapy.

Adult↗
PubMed2001

Gasless laparoscopy-assisted colorectal surgery.

BACKGROUND: Laparoscopy has gained wide acceptance as a treatment modality in a variety of colonic and rectal disorders. Currently, most laparoscopic procedures are performed using a carbon dioxide (CO2) pneumoperitoneum, which can lead to cardiopulmonary loading and subsequent complications. The object of this study was to assess the feasibility of gasless laparoscopy-assisted colorectal surgery (GLACS) as an alternative method. METHODS: Patients with benign colonic lesions were enrolled in the study. The operative field was exposed with a subcutaneous wire lifting system. A small incision, ~5 cm in length, was made early in the operation. The surgeon operated through the trocar ports and this incision using both laparoscopic and conventional instruments. The cardiopulmonary responses of the patients were monitored continuously during the operation. RESULTS: Fifteen consecutive patients underwent GLACS. In two patients (13.3%), conversion to open surgery was necessary. The exposure and ease of the procedure were acceptable. However, when the patients were stratified into hemicolectomy and sigmoidectomy groups, GLACS scored more favorably in the sigmoidectomy group. There were no operative deaths. One minor complication developed postoperatively. All of the patients recovered uneventfully, with return of bowel function in 2.8 +/- 0.1 days. The mean postoperative hospital stay was 6.4 +/- 0.4 days. The cardiac and pulmonary status of the patients remained stable during the operation. CONCLUSION: Gasless laparoscopy-assisted colorectal surgery is technically feasible; thus, it provides an alternative means for the performance of minimal-access surgery.

Aged↗
PubMed2001

Thresholds for inertial cavitation in albunex suspensions under pulsed ultrasound conditions.

Stabilized microbubbles used as echo-contrast agents can be destroyed by ultrasonic irradiation. We have identified two pressure thresholds at which these microbubbles undergo inertial cavitation (here, defined as the collapse of gas bubbles followed by emission of an acoustic broadband noise). The first threshold (P1) corresponds to the pressure at which all the microbubbles in a cavitation field lose their property as an effective scatterer because of fragmentation or deflation. The second threshold (P2) is associated with the acoustic reactivation of the remnants of the contrast agents and is related to the onset of more violent inertial cavitation. P1 and P2 were measured as a function of the concentration of Albunex (Molecular Biosystems Inc., San Diego, CA) contrast agent, the number of transmitting acoustic cycles, and the pulse repetition frequency (PRF). The ultrasound frequency used was 1.1 MHz, and the peak negative acoustic pressures ranged from 0 to 8 MPa. Our results, measured in Isoton II (Coulter Diagnostics, Miami, FL) and whole blood solutions, showed that P1 increased with increasing Albunex concentration and decreased with increasing PRF, whereas P2 decreased with increasing Albunex concentration and was independent of the PRF. Both P1 and P2 decreased with increasing number of acoustic cycles N for N < 10 and were independent of the number of cycles for N > 10. Ultrasound images of Albunex acquired by a commercial scanner showed echo enhancement not only at pressure levels below P1 but also at levels above P2. The threshold P2 was achieved at ultrasound energies above the diagnostic level. Inertial cavitation produced at P2 was associated with a higher level of hemolysis compared with P1. The results of this investigation have potential significance for both diagnostic and therapeutic ultrasound applications.

Albumins↗
PubMed2001

Data compression for arterial pulse waveform.

The arterial pulse possesses important clinical information in traditional Chinese medicine. It is usually recorded for a long period of time in the applications of telemedicine and PACS systems. Due to the huge amount of data, by recognizing the strong correlation between successive beat patterns in arterial pulse waveform sequences, a novel and efficient data compression scheme based mainly on pattern matching is introduced. The simulation results show that our coding scheme can achieve a very high compression ratio and low distortion for arterial pulse waveform.

Computer Simulation↗
PubMed2001

[Studies on chemical constituents in root of Rumex patientia L].

OBJECTIVE: Investigating the chemical constituents in the root of Rumex patientia. METHOD: Compounds were separated by rechromatography on silica gel. Their structures were determined by spectral analysis and chemical evidence. RESULT: Eight compounds were isolated and identified as 5-methoxy-7-hydroxy-1 (3H)-benzofuranone (I), 5, 7-dihydroxy-1 (3H)-benzofuranone(II), nonadecanoic acid-2,3-dihydroxypropyl ester(III), torachrysone-8-O-beta-D-glucopyranoside(IV), gallic acid(V), beta-sitosterol(VI), beta-sitosterol-3-O-beta-D-glucopyranoside(VII) and catechin(VIII). CONCLUSION: Compound III is a new natural products, and compounds I and II were obtained from this plant for the first time.

Benzofurans↗
PubMed2001

[Study on the structure and activity of new phenolic acid compounds from Erigeron breviscapus].

AIM: To isolate and identify the active constituents of Erigeron brevisapus (Vant.) Hand.-Mazz. METHODS: The chemical constituents were isolated by silica gel column chromatography and two new compounds were obtained. Their structures were elucidated by IR, MS, 1HNMR, 13CNMR, DEPT and 2DNMR. The injury of BCMEC (bovine cerebral microvascular endothelial cell) was determined by lactic dehydrogenase (LDH), the ability of the drugs anti-oxidation and scavenging oxidation of free radical was measured by colorimetric method. RESULTS: Two new compounds have been identified as 1-O-methyl-3, 5-O-dicaffeoyl quinic acid methyl ester (III) and 5-O-caffeoyl quinic acid butyl ester (IV). CONCLUSION: Compounds III and IV are new compounds. Compound III can protect BCMEC injury by LPC.

Animals↗
PubMed2001

[Studies on the chemical constituents of Zanthoxylum dimorphophyllum Hemsl. var spinifolium Rhed. et Wils].

AIM: To study the chemical components from the dried roots of Zanthoxylum dimorphophyllum Hemsl. var spinifolium Rhed. et Wils. METHODS: Modern chromatography was used to isolate chemical components and the compounds isolated from Zanthoxylum dimorphophyllum Hems1. var spinifolium Rhed. et Wils were identified by various spectral methods. RESULTS: Five compounds were isolated and identified as 6-(2',3'-dihydroxy-3'-methybutyl)-7-acetoxy-2H-1-benzopyran-2-one (I), 6-(2',3'-dihydroxy-3'-methybutyl)-7-(beta-D-glucopyranosyloxy)- 2H-1-benzopyran-2-one (II), hexacosanoci acid (III), aurepten (IV), 6-[6'-O-(-deoxy-alpha-L-mannopyranosyl)-beta-D-benzopyran-4-one (V). CONCLUSION: All of the above compounds were isolated from the plant for the first time, among them, I is a new compound.

Coumarins↗
PubMed2001

[Two new glycosides from Erigeron breviscapus (Vant.) Hand.-Mazz].

OBJECTIVE: To study the chemical constituents from the upground part of Erigeron breviscapus. METHOD: The compounds were separated and purified by column chromatography with silica gel, and identified by IR, MS, NMR and 2D-NMR. RESULT: Two new compounds were isolated and identified as 5,4'-dihydroxy flavonod-7-O-beta-D-pyranglycuronate buthyl ester(VI) and 3,5-dimethoxy benzene carbonic acid-4-O-beta-D-pyranglucose(VII). CONCLUSION: Compounds VI and VII were new compounds.

Asteraceae↗
PubMed2000

Effects of MDR1 and MDR3 P-glycoproteins, MRP1, and BCRP/MXR/ABCP on the transport of (99m)Tc-tetrofosmin.

Multidrug resistance (MDR1) P-glycoprotein (Pgp), multidrug resistance-associated protein (MRP1), and breast cancer resistance protein (BCRP/MXR/ABCP) are members of the ATP-binding-cassette (ABC) superfamily of membrane transporters and are thought to function as energy-dependent efflux pumps of a variety of structurally diverse chemotherapeutic agents. We herein report the characterization of (99m)Tc-Tetrofosmin, a candidate radiopharmaceutical substrate of ABC transporters. (99m)Tc-Tetrofosmin showed high membrane potential-dependent accumulation in drug-sensitive KB 3-1 cells and low antagonist-reversible accumulation in MDR KB 8-5 and KB 8-5-11 cells in proportion to levels of MDR1 Pgp expression. In KB 8-5 cells, EC(50) values of the potent MDR antagonists N-(4-[2-(1,2,3, 4-tetrahydro-6,7-dimethoxy-2-isoquinolinyl)ethyl]-phenyl)-9, 10-dihydro-5-methoxy-9-oxo-4-acridine carboxamide (GF120918), (2R)-anti-5-¿3-[4-(10, 11-difluoromethanodibenzo-suber-5-yl)piperazin-1-yl]-2 -hydroxypropoxy ¿quinoline trihydrochloride (LY335979), and (3'-keto-Bmt')-[Val(2)]-cyclosporin A (PSC 833) were 40, 66, and 986 nM, respectively. Furthermore, only baculoviruses carrying human MDR1, but not MDR3, conferred both a decrease in accumulation of (99m)Tc-Tetrofosmin in host Spodoptera frugiperda (Sf9) cells and a GF120918-induced enhancement. Transport studies with a variety of stably transfected and drug-selected tumor cell lines were performed with (99m)Tc-Tetrofosmin and compared with (99m)Tc-Sestamibi, a previously validated MDR imaging agent. MDR1 Pgp readily transported each agent. To a lesser extent, MRP1 also transported each agent, likely as co-transport substrates with GSH; neither agent was a substrate for the BCRP/MXR/ABCP half-transporter. In mdr1a(-/-) and mdr1a/1b(-/-) mice, (99m)Tc-Tetrofosmin showed approximately 3. 5-fold greater brain uptake and retention compared with wild-type, with no net change in blood pharmacokinetics, consistent with transport in vivo by Pgp expressed at the capillary blood-brain barrier. Molecular imaging of the functional transport activity of ABC transporters in vivo with (99m)Tc-Tetrofosmin and related radiopharmaceuticals may enable non-invasive monitoring of chemotherapeutic and MDR gene therapy protocols.

3T3 Cells↗
PubMed2000

Integration of computer-assembled digital images and text data as evidence for the oncological record.

Digitally created visual images of pertinent patient data have been integrated with text information to formulate a visual evaluation and summary sheet (VESS) using computer processing. The VESS incorporates images of a patient's physical appearance, radiological images, pharmacokinetic graphs, and text information into a 1-page document of the patient's condition. Thus, computer processing of digital images and other information helps to refine patient data presentation, analysis, interpretation, and communication. This form of data management is especially valuable in oncological research, where clinical trials demand rapid, ongoing assessment of results and analysis of large amounts of data. The VESS is an effective mechanism for monitoring both the progress of individual patients and the endpoints of the overall clinical trial.

Diagnostic Imaging↗
PubMed2000

Restoration of elbow flexion by modified Steindler flexorplasty.

A modified Steindler flexorplasty was used to restore elbow flexion in 8 patients with post-traumatic flail elbow. In 5 patients there was associated loss of wrist and finger extension, which was treated by tendon transfer and in 2 patients an associated flail shoulder was treated by arthrodesis. The results were not compromised in patients whose flexor tendons had been transferred for wrist and finger extension. All patients had a stable and mobile elbow with marked improvement of upper limb function. Modified Steindler flexorplasty is a simple, effective and reliable procedure for the restoration of elbow flexion.

Adult↗
PubMed2000

Two new caffeoyl conjugation from Erigeron breviscapus.

Two new constituents with a novel basic skeleton were isolated from Erigeron breviscapus. On the basis of chemical and spectroscopic evidences, the structures of the new compounds were elucidated as 1R,3R-dihydroxy-4S,5R-dicaffeoyloxy cyclohexane carboxylic acid methyl ester (V), 1,4-dihydroxy-3R,5R-dicaffeoyloxy cyclohexane carboxylic acid methyl ester (VI).

Caffeic Acids↗
PubMed2000

Tumor necrosis factor gene polymorphism and septic shock in surgical infection.

OBJECTIVES: To evaluate the relationship of the genotype distribution of the tumor necrosis factor (TNF)-alpha polymorphism with regard to the plasma TNF-alpha concentration and the development of septic shock as well as mortality of infected patients in a surgical intensive care unit (SICU). DESIGN: A total of 112 postoperative critically ill infected patients were prospectively enrolled. SETTING: SICU of a tertiary university-affiliated medical center. PATIENTS: Patients who were consecutively admitted to the SICU because of surgical infection with sepsis. INTERVENTION: Blood sampling. MEASUREMENTS AND MAIN RESULTS: Blood sample was obtained 24 hrs after intensive care unit (ICU) admission or within 2 hrs after the onset of septic shock to determine the plasma TNF-alpha level and to analyze the genotype of the biallelic polymorphism of the TNF-alpha. RESULTS: The allele frequency of the TNF2 in our infected ICU patients was 12%. Forty-two (37.5%) patients admitted fulfilled the criteria of septic shock during their ICU stay. Patients carrying the TNF2 allele were not more likely to develop septic shock, nor did they have a higher mortality rate. In the patients with septic shock, those carrying the TNF2 allele had a significantly higher mortality rate than those with the homozygous TNF1 genotype (92% vs. 62%, p < .05). In those who developed septic shock, the TNF2 allele was significantly associated with higher TNF levels. CONCLUSION: In patients admitted to SICU with surgical infection, the frequency of TNF2 allele was higher than in the general population. SICU patients with TNF2 allele did not show a higher incidence of developing septic shock, nor was there a higher baseline TNF-alpha level after infection. However, once septic shock had developed, the mortality rate was higher in those patients carrying the TNF2 allele.

APACHE↗