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Mughal MR, Baharani A, Chigurupati S, Son TG, Chen E, Yang P, Okun E, Arumugam T, Chan SL, Mattson MP. Electroconvulsive shock ameliorates disease processes and extends survival in huntingtin mutant mice. Hum Mol Genet 2011. [DOI: 10.1093/hmg/ddr082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Chan SL, Goh BC, Chia KS, Chuah B, Wong A, Lim R, Lee SC. Effects of CYP4F2 and GGCX genetic variants on maintenance warfarin dose in a multi-ethnic Asian population. Thromb Haemost 2011; 105:1100-2. [PMID: 21475774 DOI: 10.1160/th11-01-0018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2011] [Accepted: 02/04/2011] [Indexed: 11/05/2022]
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Chan SL, Mo F, Wong SC, Hui EP, Loong HH, Mok T, Chan AT, Yeo W. The significance of serum interleukin-10 on the outcome of unresectable hepatocellular carcinoma (HCC). J Clin Oncol 2011. [DOI: 10.1200/jco.2011.29.4_suppl.205] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
205 Background: Serum interleukin-10 (IL-10) is associated with active hepatitis in patients (pts) with hepatitis B viral (HBV) infection. In HBV-related HCC, elevation of serum IL-10 is frequently observed but its significance on the outcome of HCC is unclear. Methods: A prospective cohort of newly diagnosed and inoperable HCC was recruited from a multidisciplinary clinic from Prince of Wales Hospital from 2006 to 2008. The baseline demographics, tumor characteristics/stage, laboratory parameters, virologic factors (HBV DNA, antiviral therapy) and first-line treatment modality were documented at the time of diagnosis. Serum IL-10 was measured by enzyme-linked immunosorbent essay. Univariate and multivariate analyses were conducted. Overall survival (OS) was the primary endpoint. Results: Total 180 new cases of inoperable HCC were evaluated. The median follow-up time was 15.5 months. Median age was 60.5 years. Most (159 pts; 88.3%) were males. 81.1% of them were positive for HBsAg. Total 120 (66.7%) had radiologic evidence of cirrhosis. 20 (11.1%), 85 (47.2%) and 75 (41.7%) received locoablative, trans- arterial/systemic therapy and supportive care respectively. The mean level of serum IL-10 was 18.1pg/ml (range: 2.8-11.7). 114 (63.3%) had log IL-10 higher than 1.0 pg/ml. Pts with log IL-10 >1.0 pg/ml had significantly worse OS than those with log IL-10≤ 1.0 pg/ml (14.8 vs. 4.5 months; HR 2.39; p<.0001). Multivariate analysis found log IL-10 (HR=2.57; p=0.005), CLIP score, TNM stage, treatment modality and the use of anti-viral therapy for HBV infection be the independent prognostic factors. Exploratory analyses showed that pts with Log IL-10>1.0pg/ml had higher ALT and HBV DNA, lower albumin, higher chance of ascites, worse Child-Pugh stage and worse tumor stage (Table). Conclusions: Serum IL-10 is an independent prognostic factor for inoperable HCC. Pts with high IL-10 level have poorer liver reserves and worse tumor staging. [Table: see text] No significant financial relationships to disclose.
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Chan SL, Yew WW, Porter JH, McAdam KP, Allen BW, Dickinson JM, Ellard GA, Mitchison DA. Comparison of Chinese and Western rifapentines and improvement of bioavailability by prior taking of various meals. Int J Antimicrob Agents 2010; 3:267-74. [PMID: 18611569 DOI: 10.1016/0924-8579(94)90054-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/16/1993] [Indexed: 12/01/2022]
Abstract
Bioavailability was measured by rifapentine (RPE) serum concentrations and by the urinary ratio between RPE and creatinine, in specimens obtained 4-50 h after 600 mg RPE preceded by food. The bioavailabilities of RPEs manufactured in China and by a Western manufacturer were similar after a standard English breakfast, and serum concentrations were also similar to those obtained in an earlier Italian study following a complex meal. Although absorption of RPE was unsatisfactory after lipid-rich biscuits or shortbread, absorption after egges and toast was excellent and was nearly as good after a fast-food sandwich. The urinary measure of bioavailability at 26 h appeared as efficient as peak serum estimations at 6, 8 and 26 h. Fast-food sandwiches are being taken before RPE in a current clinical trial of Chinese RPE in Hong Kong.
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Wong VW, Mo F, Liem GS, Mok T, Chan AT, Chan HL, Yeo W, Chan SL. The impact of antiviral therapy on the outcome of hepatitis B viral (HBV)-related hepatocellular carcinoma (HCC) detected in surveillance prorgram. J Clin Oncol 2010. [DOI: 10.1200/jco.2010.28.15_suppl.4028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Wang L, Goh BC, Lwin TW, Lee H, Chan SL, Lim RS, Chan AT, Yeo W. Phase I pharmacokinetics and metabolic pathway of belinostat in patients with hepatocellular carcinoma. J Clin Oncol 2010. [DOI: 10.1200/jco.2010.28.15_suppl.2585] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Yeo W, Mo FKF, Hui P, Chan SL. Need of stratifying patients according to severity of underlying liver disease for hepatocellular carcinoma patients undergoing systemic therapy trials. Contemp Clin Trials 2010; 31:135. [PMID: 20123038 DOI: 10.1016/j.cct.2010.01.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2009] [Accepted: 01/27/2010] [Indexed: 11/30/2022]
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Ma BBY, Hui EP, Wong SCC, Tung SY, Yuen KK, King A, Chan SL, Leung SF, Kam MK, Yu BKH, Zee B, Chan ATC. Multicenter phase II study of gemcitabine and oxaliplatin in advanced nasopharyngeal carcinoma--correlation with excision repair cross-complementing-1 polymorphisms. Ann Oncol 2009; 20:1854-9. [PMID: 19549713 DOI: 10.1093/annonc/mdp065] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Nasopharyngeal carcinoma (NPC) is a platinum-sensitive cancer and excision repair cross-complementing group 1 (ERCC1) polymorphisms have been shown to predict survival in several cancers following platinum therapy. PATIENTS AND METHODS This multicenter study evaluated the activity of oxaliplatin and prolonged infusion of gemcitabine ('GEMOX' regimen) in recurrent NPC. Baseline blood samples were genotyped for the presence of ERCC1-118 gene polymorphisms. RESULTS Forty-two patients were recruited, of whom most (61%) had metastatic disease. Of the 40 patients evaluated for response, the respective overall response and disease control rates were 56.1% and 90.2%. At a median follow-up of 14.8 months, the respective median overall survival and time to progression were 19.6 months [95% confidence interval (CI) = 12.8-22 months] and 9 months (95% CI = 7.3-10 months). Grade 3-4 toxic effects were uncommon. The distribution of ERCC1-118 genotypes from 29 patients was C/C (n = 17, 40.5%), C/T (n = 10, 23.8%) and T/T (n = 2, 4.8%). No differences in survival or response rates were found between genotypes. CONCLUSIONS GEMOX is active in the treatment of recurrent NPC. Detection of single-nucleotide gene polymorphisms from genomic DNA in peripheral blood is feasible in NPC and further studies are warranted.
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Yeo W, Mo FK, Hui EP, Lam KC, Ho WM, Koh J, Ma B, Mok T, Chan A, Chan SL. Does severity of underlying chronic liver disease (CLD) affect treatment outcome of hepatocellular carcinoma (HCC) patients undergoing systemic chemotherapy (CT)? J Clin Oncol 2009. [DOI: 10.1200/jco.2009.27.15_suppl.e15513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
e15513 Background: HCC is a common cause of morbidity and mortality. CT has been one of the treatments offered to patients (pts) who are not candidate of curative surgery. Treatment of HCC could be complicated by underlying CLD. In this study, we aimed to assess pre-CT severity of CLD on treatment outcome of HCC pts who were entered into our previously reported phase III prospective randomized CT study (J Natl Cancer Inst 2005). Methods: The severity of CLD for each pt was arbitrary assessed by adopting the Child-Pugh's classification. Patients’ characteristics were compared. Treatment outcomes in terms of responses, survival and treatment-related toxicities (NCI CTC) were compared. Results: 160 were Child's A; 28 were Child's B. Proportion of pts with cirrhosis (45% vs 71%, P=0.01) and pre-CT bilirubin level (11 vs. 15 umol/l, p=0.02) were significantly higher, while age (52 vs 45 yrs, p=0.05) and albumin level (35 vs 30 g/l, p<0.0001) were significantly lower among Child's B pts. For Child's A and B pts: the median no. of CT cycles received were 4.0 vs 2.5 (p=0.01), the response rates were 17% vs 8.3% (p=0.28), the median survival were 21 vs 10.7 months (p= 0.002). When toxicity during CT were compared, Child's B pts had significantly higher rate of grade 3/4 neutropenia (0.6% vs. 7.1%, p=0.05), hyperbilirubinaemia (11.9% vs. 28.6%, p=0.02), hyponatremia (3.1% vs. 3.6%, p=0.001) and gastrointestinal bleeding (3.1% vs. 17.9%, p=0.001). Conclusions: Child's B HCC pts experienced increased treatment-related toxicities during CT. This has probably led to a shorter duration of CT and a lower response rate to CT. Their shorter survival could also be attributed to the severity of underlying CLD. Future trials on systemic therapy in HCC patients may need to consider stratifying patients according to severity of CLD. No significant financial relationships to disclose.
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Chan SL, Mo FK, Koh J, Hui EP, Yu SC, Lai PB, Chan HL, Chan VT, Chan AT, Yeo W, Mok T. Predictors of treatment outcomes in early stage hepatocellular carcinoma (HCC) detected in a surveillance program. J Clin Oncol 2009. [DOI: 10.1200/jco.2009.27.15_suppl.4584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
4584 Background: Surveillance for HCC in hepatitis B virus (HBV) carriers aims to improve survival by detection of early resectable tumor. In 2005, our group reported low surgical resection rates despite detection of small sized tumors in a prospective surveillance cohort of 1018 HBV carriers (Mok TS et al. J Clin Oncol 05). In current study, we aim to identify predictive factors for treatment outcomes in HCC detected from our surveillance program. Methods: The prospective cohort was recruited at the Prince of Wales Hospital between Oct 1997 and Nov 2000. We updated the database in Dec 2008 and performed univariate and multivariate analysis on clinical (age, sex, cirrhosis, ascites, anti-viral therapy, bilirubin, ALT, albumin, INR), tumorous (size, number, resection) and virologic factors (HBV DNA, Genotype) for prediction of outcome in HCC patients (pts). Results: In the prospective cohort, total 923 HBV carriers were updated (95 lost to follow-up). After median follow-up of 9.95 years, we confirmed diagnosis of 105 HCC. Median age = 51 (range: 40–69); M:F = 82:23; Child's A and B cirrhosis = 38:67. Fifty seven pts (54.3%) had solitary tumor but only 34 (32.4%) are amenable to resection. Absence of cirrhosis (p=0.0072) and normal albumin level (p=0.0379) are predictors of surgical resection while tumor size and number are not. The median survival of all HCC pts was 2.26 years. Anti-viral therapy during the surveillance period is a strong predictor of survival (3.74 vs. 1.63 years; p=0.0115). In multivariate analysis, both anti- viral therapy (HR=0.35; 95%CI: 0.19–0.73; p=0.0041) and normal bilirubin level (HR=0.30; 95% CI: 0.25–0.80; p=0.0069) were predictive of improved survival in pts with HCC. The benefits of anti-viral therapy applied to both surgical and non-surgical candidates (p=0.17). Conclusions: Anti-viral therapy is a potent predictor of survival of HBV related HCC. Liver function is more important than tumor characteristics in determining the outcome of HCC detected in the surveillance program. No significant financial relationships to disclose.
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Yeo W, Liem TG, Chan SL, Hui PE, Lam KC, Ma BB, Koh J, Mok TS, Leung TW, Chan AT, Mo FK. Prognostic system for hepatitis B virus (HBV)-related hepatocellular carcinoma- Prospective validation of the Chinese University Prognostic Index. J Clin Oncol 2008. [DOI: 10.1200/jco.2008.26.15_suppl.4591] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Chan SL, Mo FK, Mok TS, Hui EP, Ma BB, Ho WM, Leung TW, Liem TG, Chan AT, Yeo W. Serial alpha-feto protein in predicting radiological response and overall survival of patient with inoperable hepatocellular carcinoma (HCC) during chemotherapy. J Clin Oncol 2008. [DOI: 10.1200/jco.2008.26.15_suppl.4602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Ma BB, Leung SF, Kam MK, Hui EP, King AD, Chan SL, Yu BK, Chiu SK, Lee FH, Chan AT. A phase II study of concurrent cetuximab-cisplatin and intensity-modulated radiotherapy (IMRT) in locoregionally advanced nasopharyngeal carcinoma (NPC) with correlation using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). J Clin Oncol 2008. [DOI: 10.1200/jco.2008.26.15_suppl.6055] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Kam MK, Ma BB, Leung SF, Hui EP, Chan SL, Yu BK, Chiu SK, Chau RM, Kwan WH, Chan AT. Dose-volume analysis of radiation dermatitis among nasopharyngeal carcinoma patients treated with comcurrent cetuximab-cisplatin and intensity-modulated radiotherapy. J Clin Oncol 2008. [DOI: 10.1200/jco.2008.26.15_suppl.17015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Hui EP, Ma BB, Chan SL, Ho R, Wong WL, Taylor GS, Steven NM, Rickinson AB, Chan AT. Therapeutic vaccination with modified vaccinia Ankara (MVA) encoding Epstein-Barr virus (EBV) target antigens in EBV+ nasopharyngeal carcinoma (NPC). J Clin Oncol 2008. [DOI: 10.1200/jco.2008.26.15_suppl.3052] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Yeo W, Mo FKF, Suen JJS, Ho WM, Chan SL, Lau W, Koh J, Yeung WK, Kwan WH, Lee KKC, Mok TSK, Poon ANY, Lam KC, Hui EK, Zee B. A randomized study of aprepitant, ondansetron and dexamethasone for chemotherapy-induced nausea and vomiting in Chinese breast cancer patients receiving moderately emetogenic chemotherapy. Breast Cancer Res Treat 2008; 113:529-35. [PMID: 18327706 DOI: 10.1007/s10549-008-9957-9] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2008] [Accepted: 02/26/2008] [Indexed: 11/25/2022]
Abstract
OBJECTIVES This is a single center, randomized, double-blind placebo-controlled study to evaluate the NK(1)-receptor antagonist, aprepitant, in Chinese breast cancer patients. The primary objective was to compare the efficacy of aprepitant-based antiemetic regimen and standard antiemetic regimen for the prevention of chemotherapy-induced nausea and vomiting (CINV) in patients who received moderately emetogenic chemotherapy. The secondary objective was to compare the patient-reported quality of life in these two groups of patients. PATIENTS AND METHODS Eligible breast cancer patients were chemotherapy-naive and treated with adjuvant AC chemotherapy (i.e. doxorubicin 60 mg/m(2) and cyclophosphamide 600 mg/m(2)). Patients were randomly assigned to either an aprepitant-based regimen (day 1, aprepitant 125 mg, ondansetron 8 mg, and dexamethasone 12 mg before chemotherapy and ondansetron 8 mg 8 h later; days 2 through 3, aprepitant 80 qd) or a control arm which consisted of standard regimen (day 1, ondansetron 8 mg and dexamethasone 20 mg before chemotherapy and ondansetron 8 mg 8 h later; days 2 through 3, ondansetron 8 mg bid). Data on nausea, vomiting, and use of rescue medication were collected with a self-report diary, patients quality of life were assessed by self-administered Functional Living Index-Emesis (FLIE). RESULTS Of 127 patients randomized, 124 were assessable. For CINV in Cycle 1 AC, there was no significant difference in the proportion of patients with reported complete response, complete protection, total control, 'no vomiting', 'no significant nausea' and 'no nausea'. The requirement of rescue medication appears to be lesser in patients treated with the aprepitant-based regimen compared to those with the standard regimen (11% vs. 20%; P = 0.06). Assessment of FLIE revealed that while there was no difference in the nausea domain and the total score between the two groups; however, patients receiving standard antiemetic regimen had significantly worse quality of life in the vomiting domain (mean score [SD] = 23.99 [30.79]) when compared with those who received the aprepitant-based regimen (mean score [SD] = 3.40 [13.18]) (P = 0.0002). Both treatments were generally well tolerated. Patients treated with the aprepitant-based regimen had a significantly lower incidence of neutropenia (53.2% vs. 35.5%, P = 0.0468), grade >or= 3 neutropenia (21.0% vs. 45.2, P = 0.0042) and delay in subsequent cycle of chemotherapy (8.1% vs. 27.4%, P = 0.0048). CONCLUSION The aprepitant regimen appears to reduce the requirement of rescue medication when compared with the control regimen for prevention of CINV in patients receiving both an anthracycline and cyclophosphamide, and is associated with a better quality of life during adjuvant AC chemotherapy.
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Mokrab Y, Bavro VN, Mizuguchi K, Todorov NP, Martin IL, Dunn SMJ, Chan SL, Chau PL. Exploring ligand recognition and ion flow in comparative models of the human GABA type A receptor. J Mol Graph Model 2007; 26:760-74. [PMID: 17544304 DOI: 10.1016/j.jmgm.2007.04.012] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2007] [Accepted: 04/29/2007] [Indexed: 11/25/2022]
Abstract
We present two comparative models of the GABA(A) receptor. Model 1 is based on the 4-A resolution structure of the nicotinic acetylcholine receptor from Torpedo marmorata and represents the unliganded receptor. Two agonists, GABA and muscimol, two benzodiazepines, flunitrazepam and alprazolam, together with the general anaesthetic halothane, have been docked to this model. The ion flow is also explored in model 1 by evaluating the interaction energy of a chloride ion as it traverses the extracellular, transmembrane and intracellular domains of the protein. Model 2 differs from model 1 only in the extracellular domain and represents the liganded receptor. Comparison between the two models not only allows us to explore commonalities and differences with comparative models of the nicotinic acetylcholine receptor, but also suggests possible protein sub-domain interactions with the GABA(A) receptor not previously addressed.
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Fraser M, Chan SL, Chan SSL, Fiscus RR, Tsang BK. Regulation of p53 and suppression of apoptosis by the soluble guanylyl cyclase/cGMP pathway in human ovarian cancer cells. Oncogene 2006; 25:2203-12. [PMID: 16288207 DOI: 10.1038/sj.onc.1209251] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Dysregulated apoptosis plays a critical role in the development of a number of aberrant cellular processes, including tumorigenesis and chemoresistance. However, the mechanisms that govern the normal apoptotic program are not completely understood. Soluble guanylyl cyclase (sGC) and cyclic guanosine monophosphate (cGMP) promote mammalian cell viability via an unknown mechanism and p53 status is a key determinant of cell fate in human ovarian cancer cells. Whether an interaction exists between these two determinants of cell fate is unknown. We hypothesized that basal sGC activity reduces p53 content and attenuates p53-dependent apoptosis in human ovarian cancer cells. Suppression of sGC activity with the specific inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) lowered cGMP content, and increased p53 protein content and induced apoptosis in three ovarian cancer cell lines, effects which were attenuated by the cGMP analog 8-Br-cGMP and by Atrial Natriuretic Factor, an activator of particulate guanylyl cyclase, which circumvent the inhibition of sGC. ODQ prolonged p53 half-life, induced phosphorylation of p53 on Ser15, and upregulated the p53-dependent gene products p21, murine double minute-2, and the proapoptotic, p53-responsive gene product Bax. ODQ activated caspase-3, and ODQ-induced apoptosis was inhibited by overexpression of X-linked inhibitor of apoptosis Protein. Pretreatment with the specific p53 inhibitor pifithrin or downregulation of p53 using a specific small inhibitory RNA significantly attenuated ODQ-induced apoptosis. Moreover, ODQ-induced upregulation of p21 and Bax and ODQ-induced apoptosis were significantly reduced in a p53 mutant cell line relative to the wild-type parental cell line. Thus, the current study establishes that basal sGC/cGMP activity regulates p53 protein stability, content, and function, possibly by altering p53 phosphorylation and stabilization, and promotes cell survival in part through regulation of caspase-3 and p53.
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Thompson AJ, Chau PL, Chan SL, Lummis SCR. Unbinding pathways of an agonist and an antagonist from the 5-HT3 receptor. Biophys J 2006; 90:1979-91. [PMID: 16387779 PMCID: PMC1386777 DOI: 10.1529/biophysj.105.069385] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2005] [Accepted: 11/09/2005] [Indexed: 11/18/2022] Open
Abstract
The binding sites of 5-HT3 and other Cys-loop receptors have been extensively studied, but there are no data on the entry and exit routes of ligands for these sites. Here we have used molecular dynamics simulations to predict the pathway for agonists and antagonists exiting from the 5-HT3 receptor binding site. The data suggest that the unbinding pathway follows a tunnel at the interface of two subunits, which is approximately 8 A long and terminates approximately 20 A above the membrane. The exit routes for an agonist (5-HT) and an antagonist (granisetron) were similar, with trajectories toward the membrane and outward from the ligand binding site. 5-HT appears to form many hydrogen bonds with residues in the unbinding pathway, and experiments show that mutating these residues significantly affects function. The location of the pathway is also supported by docking studies of granisetron, which show a potential binding site for granisetron on the unbinding route. We propose that leaving the binding pocket along this tunnel places the ligands close to the membrane and prevents their immediate reentry into the binding pocket. We anticipate similar exit pathways for other members of the Cys-loop receptor family.
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Ali-Khan Z, Li W, Chan SL. Animal model for the pathogenesis of reactive amyloidosis. ACTA ACUST UNITED AC 2005; 12:297-302. [PMID: 15275180 DOI: 10.1016/0169-4758(96)10032-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The pathogenesis of amyloidosis is not well understood. Here, Zafer Ali-Khan, Weihua Li and Sic L. Chan present a metazoan parasite mouse model of reactive amyloidosis, review the relationship between chronic inflammation and multiorgan AA amyloidosis and postulate how ubiquitin might function in the processing of serum amyloid A and in AA amyloid formation in the endosomes-lysosomes of activated murine reticuloendothetial cells.
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Chan SL, Luman W. Appropriateness of the use of parenteral nutrition in a local tertiary-care hospital. ANNALS OF THE ACADEMY OF MEDICINE, SINGAPORE 2004; 33:494-8. [PMID: 15329763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/30/2023]
Abstract
INTRODUCTION Parenteral nutrition (PN) is an important supportive therapy for critically ill patients who have non-functioning gut. However, it is an expensive therapy and carries significant complications. The objective of our audit was to determine the appropriateness of prescription of PN in our hospital, based on the American Society for Parenteral and Enteral Nutrition (ASPEN) 2002 guidelines. In our hospital, the prescription of PN is managed by the Nutrition Support Team. MATERIALS AND METHODS A retrospective review of adult patients prescribed with PN in 2001 was undertaken. Data on patient demographics, underlying diagnoses, indications, duration and routes administration were collected. The use of PN was classified as "appropriate", "inappropriate" or "indeterminate" by the authors based on the above guidelines. RESULTS 145 patients were prescribed PN in 2002. We were able to review the case notes for 137 patients. One patient received PN on 2 separate admissions. Of the 138 courses of PN (in 137 patients) reviewed, there were 88 males with the median age of 61 years (range, 16 to 91 years). 81.2% were surgical patients and of the remaining patients, 10.1% had haematological malignancies. The 2 most common indications were postoperative ileus (37.0%) and post-surgical complications (14.5%). The median duration of PN prescription was 9 days (range, 1 to 175 days). 109 (78.3%) courses of PN were classified as "appropriate", 22 (15.9%) courses as "inappropriate" and 7 (5.8%) courses as "indeterminate". Patients from the postoperative ileus group contributed to 10 (45.5%) patients with "inappropriate" indications; the main reason was premature initiation of PN. Of the patients considered to show "inappropriate" indications, 15 courses (68.1%) were prescribed for less than 7 days. PN was discontinued in 78% of courses due to satisfactory resumption of oral or enteral intake. The mean duration of PN use for patients with "inappropriate" indication was significantly shorter than for patients with "appropriate" indication (7.7 +/- 5.3 days versus 15.8 +/- 20.0 days, P = 0.002). 99.3% of PN courses were given via the central routes (with central vein cannulation or PICC). These lines were specifically inserted for PN in 60.14% of the cases. CONCLUSION Our audit showed that 15.9% of PN prescriptions were inappropriate according to the ASPEN guidelines. This was largely attributed to premature initiation of PN for postoperative ileus. We believe that these PN courses could have been avoided if these patients had been tried on naso-jejunal tube feeding, or oral nutrition with the use of prokinetics during the postoperative period.
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Wang M, Dunn WR, Chan SL, Garfield B, Wilson VG. Evidence for Nonadrenoceptor Responses to Imidazoline Derivatives in the Porcine Isolated Rectal Artery. Ann N Y Acad Sci 2003; 1009:386-91. [PMID: 15028617 DOI: 10.1196/annals.1304.052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
High concentrations of phentolamine, efaroxan, and idazoxan were found to produce nonadrenoceptor contractions of the porcine isolated rectal artery previously exposed to U46619 and forskolin. These responses were insensitive to the putative imidazoline I(3) receptor antagonist KU-14R, unlike those previously reported in this preparation for oxymetazoline. The pharmacologic nature of this response and the obligate requirement for preconstriction suggests that these imidazoline derivatives modulate ion channel function through a novel nonadrenergic site.
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Chan-Yeung M, Noertjojo K, Leung CC, Chan SL, Tam CM. Prevalence and predictors of default from tuberculosis treatment in Hong Kong. Hong Kong Med J 2003; 9:263-8. [PMID: 12904614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/04/2023] Open
Abstract
OBJECTIVE To determine the prevalence and risk factors of default from tuberculosis treatment in Hong Kong. DESIGN Retrospective study. SETTING Data were obtained from programme forms completed by physicians in the Hong Kong Government Tuberculosis and Chest Service and from medical records from Hong Kong chest clinics. PATIENTS In all, 5917 patients registered for antituberculous drug therapy in 1996; medical records of 5757 patients were reviewed. MAIN OUTCOME MEASURES Patients who defaulted treatment were defined as those who had failed to collect medication for more than 2 consecutive months after the date of the last attendance during the course of treatment. Demographic and clinical characteristics, including history, treatment, and outcome, were compared between defaulters and non-defaulters, both among the whole group and among those with pulmonary disease. RESULTS There were 442 (8%) patients who defaulted from treatment. Forty-five percent of those who defaulted did so in the first 2 months of treatment. Key risk factors associated with non-compliance were a history of default, male sex, and a history of concomitant liver disease or lung cancer. Among patients with pulmonary tuberculosis (381 defaulters and 1537 non-defaulters), multiple drug resistance was also associated with default from treatment. Among defaulters with pulmonary disease, 39% were still bacteriologically positive at the time of default. CONCLUSION Default from treatment may be partially responsible for the persistent high rates of tuberculosis in Hong Kong in the past decade. Health professionals should ensure that all barriers to treatment be removed and that incentives be used to encourage treatment compliance.
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Tam CM, Leung CC, Noertjojo K, Chan SL, Chan-Yeung M. Tuberculosis in Hong Kong-patient characteristics and treatment outcome. Hong Kong Med J 2003; 9:83-90. [PMID: 12668817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/01/2023] Open
Abstract
OBJECTIVES To identify the general characteristics of patients with tuberculosis, and to evaluate their treatment outcomes. DESIGN Retrospective study. SETTING Tuberculosis and Chest Service, Department of Health, Hong Kong. SUBJECTS AND METHODS All patients with tuberculosis registered for treatment from 1 January 1996 to 31 December 1996 were included in the study. Information was extracted from their medical records at treatment commencement and at 12 and 24 months after treatment was instigated. Data gathered included demographic data, past treatment, site of disease, case category, treatment regimen, bacteriological status, and treatment outcome. RESULTS There were 5757 patients for analysis. Approximately one third of patients were aged 60 years or older, and 69.1% were male. Pulmonary disease alone occurred in 77.7% of patients, while both pulmonary and extrapulmonary diseases occurred in 8.6%. New patients comprised 84.6% of cases, and 16.3% had concomitant illnesses. There was excess risk of disease among patients who were male, elderly, or who had silicosis. Only 0.1% of patients were co-infected with human immunodeficiency virus infection. Among the 5757 cases evaluated, 1324 (23.0%) were new patients with a positive sputum smear, 299 (5.2%) were patients who were retreated with a positive sputum smear, and 4134 (71.8%) were new or retreatment patients with a negative sputum smear. The overall treatment completion rates at 12 and 24 months were 80.4% and 84.8%, respectively. Males and patients aged 60 years or older had lower treatment completion rates. Non-adherence, transfer to other services, and mortality among the elderly were key factors influencing treatment outcomes. Co-morbidity was associated with better case-holding, and this more than compensated for its effect on prolongation of treatment and mortality. CONCLUSIONS There was an excess risk of tuberculosis among male and elderly patients, who also had a less favourable outcome. Active screening of clearly identified risk groups may be appropriate but requires the completion of more in-depth studies and careful cost-effectiveness analyses. Further efforts with respect to case-holding are indicated to address treatment defaulting and transfer rates.
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