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Biomedical subjects

C C Chen

Publications and source records attributed to C C Chen.

At least 109 records · Page 6Linked to original sources
PubMed2001

Comparison of a novel electro-Fenton method with Fenton's reagent in treating a highly contaminated wastewater.

This study applied a novel electrochemical process called the Fered-Fenton method to treat a highly concentrated wastewater. By combining electrochemical reduction and chemical oxidation, the process can remove organic compounds and heavy metals in a batch reactor. A PVC-stabilizer processing wastewater was treated in this investigation owing to its high heavy metal concentration (Pb = 7,500 mg/l) and high organic concentration (COD = 11,000 mg/l). The major organic component was acetate. Direct anodic oxidation showed no effect on COD removal. Fenton's method only removed 36% of COD using 4,000 mg-Fe2+/l and 28,000 mg-H2O2/l dosage. In the Fered-Fenton process, about 89% of COD was removed with 2,000 mg-Fe3+/l and 28,000 mg-H2O2/l. Furthermore, the COD removal attained an efficiency of about 98% for 56,000 mg-H2O2/l used. Results presented herein demonstrate that the Fered-Fenton method is superior to direct anodic oxidation and Fenton's method in this case. Furthermore, the changes of the intermediate compounds including acetate, oxadate, and formate during the reaction were analyzed, which provided us with the information to propose degradation reactions of the wastewater in this system.

Electrochemistry↗
PubMed2001

Comparison of the metabolic effects of metformin and troglitazone on fructose-induced insulin resistance in male Sprague-Dawley rats.

BACKGROUND AND PURPOSE: Insulin resistance is a hallmark of the development of type 2 diabetes. Metformin and troglitazone are oral antidiabetic agents used to reduce insulin resistance. The aim of this study was to compare the metabolic effects of these two drugs in fructose-induced insulin-resistant rodents. METHODS: Male Sprague-Dawley rats were allocated to receive one of the following four treatments for 6 weeks: normal rat chow (control group, n = 7), high-fructose diet (fructose group, n = 7), high-fructose diet plus metformin (metformin group, n = 8), or high-fructose diet plus troglitazone (troglitazone group, n = 8). Systolic blood pressure (SBP), insulin, free fatty acid (FFA), and triglyceride concentrations were measured as parameters of insulin resistance. Leptin concentration was also measured in the four groups. RESULTS: The fructose group developed significantly elevated SBP, hyperinsulinemia, and hypertriglyceridemia without significant change in body weight or leptin concentration compared with the control group. The metformin group had significantly reduced body weight (397.9 +/- 40.9 vs 470.1 +/- 59.6 g, p < 0.05), insulin concentration (14.8 +/- 10.5 vs 48.4 +/- 15.2 microU/mL, p < 0.05), triglyceride concentration (75.3 +/- 65.5 vs 250.1 +/- 95.7 mg/dL, p < 0.05), and leptin concentration (3.1 +/- 1.5 vs 6.9 +/- 2.0 ng/mL, p < 0.05) without significant change in SBP (147.8 +/- 5.8 vs 152.4 +/- 13.0 mm Hg, p > 0.05) compared with the fructose group. The troglitazone group had significantly reduced SBP (137.8 +/- 9.2 vs 152.4 +/- 13.0 mm Hg, p < 0.05), insulin concentration (15.0 +/- 13.6 vs 48.4 +/- 15.2 microU/mL, p < 0.05), FFA concentration (38.9 +/- 22.7 vs 78.7 +/- 24.6 mg/dL, p < 0.05), triglyceride concentration (67.6 +/- 32.4 vs 250.1 +/- 95.7 mg/dL, p < 0.05), and leptin concentration (4.4 +/- 2.0 vs 6.9 +/- 2.0 ng/mL, p < 0.05) without significant change in body weight (452.5 +/- 32.8 vs 470.1 +/- 59.6 g, p > 0.05) compared with the fructose group. The metabolic effects of metformin and troglitazone on insulin, FFA, triglyceride, and leptin concentrations were not significantly different. However, metformin treatment resulted in significantly lower body weight (397.9 +/- 40.9 vs 452.5 +/- 32.8 g) and troglitazone treatment in significantly lower SBP (137.8 +/- 9.2 vs 147.8 +/- 5.8 mm Hg) compared to the fructose group, after adjusting for basal values (p < 0.05). CONCLUSIONS: Both metformin and troglitazone were comparably effective in reducing insulin resistance. Metformin treatment caused body weight reduction but was not effective in reducing SBP. Troglitazone treatment lowered SBP but did not reduce body weight.

Animals↗
PubMed2001

A randomized phase II trial of thalidomide, an angiogenesis inhibitor, in patients with androgen-independent prostate cancer.

PURPOSE: Thalidomide is a potent teratogen that causes dysmelia in humans. Recently, in vitro data suggested that it inhibits angiogenesis. Prostate cancer is dependent on the recruitment of new blood vessels to grow and metastasize. Based on those data, we initiated a Phase II trial of thalidomide in patients with metastatic androgen-independent prostate cancer. EXPERIMENTAL DESIGN: This was an open-label, randomized Phase II study. Thalidomide was administered either at a dose of 200 mg/day (low-dose arm) or at an initial dose of 200 mg/day that escalated to 1200 mg/day (high-dose arm). RESULTS: A total of 63 patients were enrolled onto the study (50 patients on the low-dose arm and 13 patients on the high-dose arm). Serum prostate-specific antigen (PSA) decline of > or = 50% was noted in 18% of patients on the low-dose arm and in none of the patients on the high-dose arm. Four patients were maintained for > 150 days. The most prevalent complications were constipation, fatigue, neurocortical, and neurosensory. CONCLUSION: Thalidomide, an antiangiogenesis agent, has some activity in patients with metastatic prostate cancer who have failed multiple therapies. A total of 27% of all patients had a decline in PSA of > or = 40%, often associated with an improvement of clinical symptoms. Because our preclinical studies had shown that thalidomide increases PSA secretion, we believe that the magnitude of PSA decline seen in our trial justifies further study.

Aged↗
PubMed2001

Huge cystic duplication of the ascending colon in adult.

Duplications of alimentary tract are uncommon congenital anomalies that are usually identified during the pediatric age. However, a minority of cases remain unsuspected until adulthood. They may be cystic or tubular in appearance and characteristically arise from the mesenteric border of the intestine. This paper reports a 37-year-old male with a huge cystic duplication of the ascending colon. In facing such a huge abdominal cystic tumor, differential diagnoses including duplication cyst, mesenteric cyst, choledochal cyst, giant diverticulum, and cystic tumor of the pancreas should be considered. Computerized tomography is a good tool for delineating the relationship between the tumor and peripheral structures. Surgery not only provides treatment but also final pathological diagnosis. Complete resection of a colonic duplication is necessary because of potential malignant change of the lesion.

Adult↗
PubMed2001

Adrenal cyst--a case report.

Adrenal cysts are rare and mostly silent clinically. Herein we report a case of adrenal cyst. A 55-year-old female was incidentally found to have a left suprarenal cystic lesion with a calcified wall by abdominal sonography during a work-up for her epigastralgia and left flank pain. Then, computed tomography (CT) revealed a left adrenal cystic mass with wall calcification, magnetic resonance imaging (MRI) showed left retroperitoneal cystic mass with fluid content, and angiography demonstrated an avascular lesion. Surgical exploration was performed via a flank incision and a calcified cystic adrenal mass was excised. The pathologic diagnosis was adrenal pseudocyst with calcified wall. We discuss the diagnosis and management of adrenal cyst and briefly review the literature.

Adrenal Gland Diseases↗
PubMed2001

Hand-assisted laparoscopic radical nephrectomy of renal cell carcinoma--a case report.

A 62-year-old female patient with chronic medical history of DM and hypertension was admitted due to traffic accident. She was asymptomatic until 5 days before admission. She was referred to our medical center with an abdominal CT revealing left renal tumor. The diameter of the renal mass was 50 mm. On ultrasonographic examination, a heterogenous lesion over the left kidney was noted. Renal scanning showed a cold nodule in the left kidney. Hand-assisted laparoscopic transperitoneal radical nephrectomy was performed smoothly. The kidney was removed from the hand port in the supraumbilical skin incision with a volume of 14 x 7 x 6 cm3 and weight of 570 gm. The operation time was 5 hours, blood loss was 200 cc, and no significant change of blood pressure was noted during the surgery. The patient's postoperative course was uneventful. The pathological report of this mass was renal cell carcinoma.

Carcinoma, Renal Cell↗
PubMed2001

Prediction of the outcome of pull-through surgery for Hirschsprung's disease using acetylcholinesterase activity.

BACKGROUND AND PURPOSE: Advances in surgical procedures for the treatment of Hirschsprung's disease have afforded the majority of patients a satisfactory outcome after definitive corrective surgery. However, some patients continue to have signs of persistent bowel dysfunction despite adequate resection of the aganglionic bowel segment. The definite etiology of persistent bowel dysfunction in these patients remains controversial. MATERIALS AND METHODS: The acetylcholinesterase activity in the proximal resection margin of pull-through surgical specimens collected from September 1992 to June 1998 was evaluated and correlated with clinical outcome. RESULTS: A total of 24 patients were studied, 15 males and 9 females. The follow-up period ranged from 1 year 7 months to 7 years 6 months. The Soave procedure was performed in 17 cases and the Duhamel in 7. Twenty cases had a good or fair clinical outcome and four (16.7%) had a poor outcome. There was no mortality. Among the 20 patients with a good or fair outcome, the acetylcholinesterase activity in the proximal section margins was not increased in 12, mildly increased in seven, and moderately increased in one. The four cases with poor outcome all had moderately increased acetylcholinesterase activity in at least one specimen. The association between moderately increased acetylcholinesterase activity and poor surgical outcome was significant (p = 0.0005). In contrast, there was no association between the surgical method (Soave or Duhamel) used and clinical outcome (p = 0.55). CONCLUSION: Acetylcholinesterase activity in the proximal resection margins of pull-through surgical specimens is a useful indicator for predicting the postoperative outcome in Hirschsprung's disease.

Acetylcholinesterase↗
PubMed2001

Premedication with low-dose oral midazolam reduces the incidence and severity of emergence agitation in pediatric patients following sevoflurane anesthesia.

BACKGROUND: Sevoflurane is a volatile anesthetic agent with low pungency, non-irritating odor, and low blood/gas partition coefficient that makes it an attractive alternative to halothane. However, a high incidence of emergence agitation (EA) has been reported in pediatric patients after sevoflurane anesthesia. The underlying mechanism of sevoflurane-induced EA remains unclear. Rapid recovery of consciousness (emergence) from sevoflurane anesthesia has been proposed as one possible mechanism. We, therefore, hypothesized that sedatives such as midazolam may counteract sevoflurane's rapid emergence and thus reduce the incidence and the severity of sevoflurane-induced EA. METHODS: A prospective, controlled, single-blinded study was carried out in 88 ASA class I or II pediatric patients scheduled for elective outpatient surgery. Patients were assigned to receive either midazolam (oral midazolam, 0.2 mg/kg as anesthetic premedication) or saline (oral normal saline as premedication) before the conduct of anesthesia. When separation from parents was due its process was watched and evaluated. Induction of anesthesia and maintenance of anesthesia were uniform in both groups. Induction of anesthesia was made possible with 8% sevoflurane and N2O in 50% O2. Intubation was performed straight without the aid of muscle relaxant and the ventilator was set to maintain normocapnia. Anesthesia was maintained with 3% sevoflurane and N2O in 50% O2 until the surgery was over. All matters of relevant time periods were recorded (induction, surgical procedure, extubation and transportation). In the post-anesthesia care unit (PACU), adverse events, the incidence and the severity of EA, analgesic requirement, duration of PACU stay, and parental as well as PACU nurses' satisfaction were evaluated. RESULTS: A significant lower incidence and less severity of EA were noted in patients premedicated with midazolam. Less postoperaive analgesia was required in patients who had received midazolam. Although midazolam-premedicated patients remained sedated after sevoflurane anesthesia, the duration of the PACU stay was not significantly different from that of saline-treated patients. Both parents and PACU nurses were more satisfied with midazolam as premedication. No solid evidence showed that there was close correlation between the process of separation from parents and the occurrence of EA. CONCLUSIONS: Premedication with oral midazolam is safe, convenient and effective in decreasing the occurrence of sevoflurane-induced EA. It does not delay discharge from PACU and is suitable for outpatient surgery.

Anesthesia, Inhalation↗
PubMed2001

Resection of triple synchronous tumors--gastric adenocarcinoma, gallbladder adenocarcinoma and stromal tumor of the stomach.

We herein report a rare case of triple synchronous tumors: gastric adenocarcinoma, gallbladder adenocarcinoma and stromal cell tumor of stomach, which were resected in the same operation. A 72-year-old male patient suffered from poor appetite and epigastric pain that radiated to his back for one month. Upper gastrointestinal endoscopy showed a gastric ulcer measuring 1.5 cm at the prepyloric area, which was proven to be adenocarcinoma by biopsy. A second tumor was found in the gallbladder, measuring 3 cm, by ultrasonography. On computed tomography, a third tumor about 2.5 cm in size was recognized posterior to the gastric high body and anterior to the pancreas. Given the presence of three tumors, he underwent a radical subtotal gastrectomy with Billroth-II gastrojejunostomy and simultaneous cholecystectomy. Pathological findings revealed gastric adenocarcinoma, gallbladder adenocarcinoma and stromal cell tumor of the stomach. The postoperative course was smooth.

Adenocarcinoma↗
PubMed2001

Endovascular aortic graft exclusion of abdominal aortic aneurysm.

Endovascular repair of abdominal aortic aneurysms has evolved dramatically within the past few years. This study reports the first successful case in Taiwan area of infrarenal abdominal aortic aneurysm treated with endovascular aortic bifurcational stent-graft. Minimally invasive surgery leading to early recovery, mobilization and shortened hospital day was promising. In addition, there were no local, remote or systemic complications during a 18-month follow-up. Thus, the procedure is an attractive alternative in its potential to reduce morbidity and mortality associated with open surgical repair, especially for patients who are not surgical candidates because of comorbidities. Careful patient selection and more experiences with refined endograft models will elucidate the feasible alternative to conventional surgical repair.

Aged↗
PubMed2001

A progressive growing inflammatory pseudotumor of the liver.

Inflammatory pseudotumors of the liver are very rare, and their etiology and pathogenesis remain unclear. The diagnosis is often difficult to make because these masses often mimic other lesions such as primary neoplasms, metastases or liver abscesses. Herein, we report a rare case of progressive growing hepatic pseudotumor in a 47-year-old man. The patient presented with body weight loss and general malaise. A series of radiological examinations showed the progressive growth of the hepatic tumor from 3.5 cm to 10.0 cm in diameter within 8 months. He underwent a right lobectomy of the liver, and the final diagnosis was proven by pathology. There were no complications in the post-operative course.

Granuloma, Plasma Cell↗
PubMed2000

Migration of endoclip into duodenum. A rare complication after laparoscopic cholecystectomy.

The long-term effect of spilled clips within the abdominal cavity after laparoscopic cholecystectomy is unknown. However, most surgeons agree that the migration of clips has limited clinical consequences. A few cases have been reported of clips that have migrated into the common bile duct, causing stone formation and/or obstructions. We present a case of gallstone pancreatitis treated with laparoscopic cholecystectomy that was complicated by bile leakage from the cystic duct stump 1 day after the procedure. Although the leaking stump sealed itself spontaneously after the placement of a biliary stent, a clip had migrated directly to the superior wall of the first portion of the duodenum. Herein the details of the patient's history are presented. We also discuss the possible mechanisms of clip migration and describe some preventive measures.

Bile↗
PubMed2000

A 72-base pair AT-rich DNA sequence element functions as a bacterial gene silencer.

We have previously demonstrated that sequential activation of the bacterial ilvIH-leuO-leuABCD gene cluster involves a promoter-relay mechanism. In the current study, we show that the final activation of the leuABCD operon is through a transcriptional derepression mechanism. The leuABCD operon is transcriptionally repressed by the presence of a 318-base pair AT-rich upstream element. LeuO is required for derepressing the repressed leuABCD operon. Deletion analysis of the repressive effect of the 318-bp element has led to the identification of a 72-bp AT-rich (78% A+T) DNA sequence element, AT4, which is capable of silencing a number of unrelated promoters in addition to the leuABCD promoter. AT4-mediated gene silencing is orientation-independent and occurs within a distance of 300 base pairs. Furthermore, an increased gene-silencing effect was observed with a tandemly repeated AT4 dimer. The possible mechanism of AT4-mediated gene silencing in bacteria is discussed.

Base Pairing↗
PubMed2000

The angiogenic factors Cyr61 and connective tissue growth factor induce adhesive signaling in primary human skin fibroblasts.

The angiogenic inducers cysteine-rich angiogenic protein 61 (Cyr61) and connective tissue growth factor (CTGF) are structurally related, extracellular matrix-associated heparin-binding proteins. Both can stimulate chemotaxis and promote proliferation in endothelial cells and fibroblasts in culture and induce neovascularization in vivo. Encoded by inducible immediate early genes, Cyr61 and CTGF are synthesized upon growth factor stimulation in cultured fibroblasts and during cutaneous wound healing in dermal fibroblasts. Recently, we have shown that adhesion of primary human fibroblasts to immobilized Cyr61 is mediated through integrin alpha(6)beta(1) and cell surface heparan sulfate proteoglycans (HSPGs) (Chen, N., Chen, C.-C., and Lau, L.F. (2000) J. Biol. Chem. 275, 24953-24961), providing the first demonstration of an absolute requirement for HSPGs in integrin-mediated cell attachment. We show in this study that CTGF also mediates fibroblast adhesion through the same mechanism and demonstrate that fibroblasts adhesion to immobilized Cyr61 or CTGF induces distinct adhesive signaling responses consistent with their biological activities. Compared with fibroblast adhesion to fibronectin, laminin, or type I collagen, cell adhesion to Cyr61 or CTGF induces 1) more extensive and prolonged formation of filopodia and lamellipodia, concomitant with formation of integrin alpha(6)beta(1)-containing focal complexes localized at leading edges of pseudopods; 2) activation of intracellular signaling molecules including focal adhesion kinase, paxillin, and Rac with similar rapid kinetics; 3) sustained activation of p42/p44 MAPKs lasting for at least 9 h; and 4) prolonged gene expression changes including up-regulation of MMP-1 (collagenase-1) and MMP-3 (stromelysin-1) mRNAs and proteins sustained for at least 24 h. Together, these results establish Cyr61 and CTGF as bona fide adhesive substrates with specific signaling capabilities, provide a molecular basis for their activities in fibroblasts through integrin alpha(6)beta(1) and HSPG-mediated signaling during attachment and indicate that these proteins may function in matrix remodeling through the activation of metalloproteinases during angiogenesis and wound healing.

Cell Adhesion↗
PubMed2000

TNF-alpha-induced cyclooxygenase-2 expression in human lung epithelial cells: involvement of the phospholipase C-gamma 2, protein kinase C-alpha, tyrosine kinase, NF-kappa B-inducing kinase, and I-kappa B kinase 1/2 pathway.

TNF-alpha induced a dose- and time-dependent increase in cyclooxygenase-2 (COX-2) expression and PGE2 formation in human NCI-H292 epithelial cells. Immunofluorescence staining demonstrated that COX-2 was expressed in cytosol and nuclear envelope. Tyrosine kinase inhibitors (genistein or herbimycin) or phosphoinositide-specific phospholipase C inhibitor (U73122) blocked TNF-alpha-induced COX-2 expression. TNF-alpha also stimulated phosphatidylinositol hydrolysis and protein kinase C (PKC) activity, and both were abolished by genistein or U73122. The PKC inhibitor, staurosporine, also inhibited TNF-alpha-induced response. The 12-O-tetradecanoylphorbol 13-acetate (TPA), a PKC activator, also stimulated COX-2 expression, this effect being inhibited by genistein or herbimycin. NF-kappaB DNA-protein binding and COX-2 promoter activity were enhanced by TNF-alpha, and these effects were inhibited by genistein, U73122, staurosporine, or pyrolidine dithiocarbamate. TPA stimulated both NF-kappaB DNA-protein binding and COX-2 promoter activity, these effects being inhibited by genistein, herbimycin, or pyrolidine dithiocarbamate. The TNF-alpha-induced, but not the TPA-induced, COX-2 promoter activity was inhibited by phospholipase C-gamma2 mutants, and the COX-2 promoter activity induced by either agent was attenuated by dominant-negative mutants of PKC-alpha, NF-kappaB-inducing kinase, or I-kappaB (inhibitory protein that dissociates from NF-kappaB) kinase (IKK)1 or 2. IKK activity was stimulated by both TNF-alpha and TPA, and these effects were inhibited by staurosporine or herbimycin. These results suggest that, in NCI-H292 epithelial cells, TNF-alpha might activate phospholipase C-gamma2 via an upstream tyrosine kinase to induce activation of PKC-alpha and protein tyrosine kinase, resulting in the activation of NF-kappaB-inducing kinase and IKK1/2, and NF-kappaB in the COX-2 promoter, then initiation of COX-2 expression and PGE2 release.

Benzoquinones↗
PubMed2000

Adhesion of human skin fibroblasts to Cyr61 is mediated through integrin alpha 6beta 1 and cell surface heparan sulfate proteoglycans.

The angiogenic inducer Cyr61 is an extracellular matrix-associated heparin-binding protein that can mediate cell adhesion, stimulate cell migration, and enhance growth factor-stimulated DNA synthesis in both fibroblasts and endothelial cells in culture. In vivo, Cyr61 induces neovascularization and promotes tumor growth. Cyr61 is a prototypic member of a highly conserved family of secreted proteins that includes connective tissue growth factor, nephroblastoma overexpressed, Elm-1/WISP-1, Cop-1/WISP-2, and WISP-3. Encoded by an immediate early gene, Cyr61 synthesis is induced by serum growth factors in cultured fibroblasts and in dermal fibroblasts during cutaneous wound healing. We previously demonstrated that Cyr61 mediates adhesion of vascular endothelial cells and activation-dependent adhesion of blood platelets through direct interaction with integrins alpha(V)beta(3) and alpha(IIb)beta(3), respectively. In this study, we show that the adhesion of primary human skin fibroblasts to Cyr61 is mediated through integrin alpha(6)beta(1) and cell surface heparan sulfate proteoglycans (HSPGs), which most likely serve as co-receptors. Either destruction of cell surface HSPGs or prior occupancy of the Cyr61 heparin-binding site completely blocked cell adhesion to Cyr61. A heparin-binding defective mutant of Cyr61 was unable to mediate fibroblast adhesion through integrin alpha(6)beta(1) but still mediated endothelial cell adhesion through integrin alpha(V)beta(3), indicating that endothelial cell adhesion through integrin alpha(V)beta(3) is independent of the heparin-binding activity of Cyr61. These results identify Cyr61 as a novel adhesive substrate for integrin alpha(6)beta(1) and provide the first demonstration of the requirement for HSPGs in integrin-mediated cell attachment. In addition, these findings suggest that Cyr61 might elicit disparate biological effects in different cell types through interaction with distinct integrin receptors.

Animals↗
PubMed2000

Long-term in vivo survival of receptor-modified syngeneic T cells in patients with human immunodeficiency virus infection.

To study human immunodeficiency virus (HIV)-specific cellular immunity in vivo, we transferred syngeneic lymphocytes after ex vivo expansion and transduction with a chimeric receptor gene (CD4/CD3-zeta) between identical twins discordant for HIV infection. Single and multiple infusions of 10(10) genetically modified CD8(+) T cells resulted in peak fractions in the circulation of approximately 10(4) to 10(5) modified cells/10(6) mononuclear cells at 24 to 48 hours, followed by 2- to 3-log declines by 8 weeks. In an effort to provide longer high-level persistence of the transferred cells and possibly enhance anti-HIV activity, we administered a second series of infusions in which both CD4(+ )and CD8(+) T cells were engineered to express the chimeric receptor and were costimulated ex vivo with beads coated with anti-CD3 and anti-CD28. Sustained fractions of approximately 10(3) to 10(4) modified cells/10(6) total CD4(+) or CD8(+) cells persisted for at least 1 year. Assessment of in vivo trafficking of the transferred cells by lymphoid tissue biopsies revealed the presence of modified cells in proportions equivalent to or below those in the circulation. The cell infusions were well tolerated and were not associated with substantive immunologic or virologic changes. Thus, adoptive transfer of genetically modified HIV-antigen-specific T cells was safe. Sustained survival in the circulation was achieved when modified CD4(+ )and CD8(+) T cells were infused together after ex vivo costimulation, indicating the important role played by antigen-specific CD4(+) T cells in providing "help" to cytotoxic effectors. (Blood. 2000;96:467-474)

Adult↗