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Ng TP, Tan CH, Kua EH. The use of Chinese herbal medicines and their correlates in Chinese older adults: the Singapore Chinese Longitudinal Aging Study. Age Ageing 2004; 33:135-42. [PMID: 14960428 DOI: 10.1093/ageing/afh016] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND There are very few studies of the use of Chinese herbal medicine and their psychosocial and health-related determinants in older adults. OBJECTIVES To determine the prevalence of use of Chinese herbal medicine in community-living Chinese older adults in Singapore and its associations with socio-economic status, social support, health behaviour, health and functional status. DESIGN Cross-sectional analyses of baseline data from a longitudinal cohort study of old adults (Singapore Chinese Longitudinal Aging Study). SETTING Community of Toa Payoh in Singapore (total population 22800 out of 3 million). PARTICIPANTS community residents comprising 2010 Chinese older adults aged 65 years and above. MEASUREMENTS participants completed a questionnaire on Chinese herbal medicine use and other information on psychosocial and health-related variables. RESULTS The use of Chinese herbal medicine over the past year was reported by 25.3% of the subjects, among whom 52% reported concurrent use of Western prescription medications. Significant factors that were strongly and independently associated with Chinese herbal medicine use were limited to extensive social support (OR = 2.66-5.56), current smoking (OR = 1.35), regular taiqi (OR = 1.94), arthritis (OR = 2.36), cancer (OR = 3.15), hypnotic use (OR = 2.08), IADL disability (OR = 1.72) and poor treatment compliance (OR = 2.35). CONCLUSION Positive and negative psychosocial and health-related factors determine the use of Chinese herbal medicine use in Chinese older adults, consistent with the dual-pattern use of Chinese herbal medicine as health supplement and complementary/alternative medicine.
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Koh LP, Hwang WYK, Tan CH, Linn YC, Goh YT, Chuah CTH, Ng HJ, Fook-Chong SMC, Tan PHC. Long term follow-up of Asian patients with chronic myeloid leukemia (CML) receiving allogeneic hematopoietic stem cell transplantation (HSCT) from HLA-identical sibling-evaluation of risks and benefits. Ann Hematol 2003; 83:286-94. [PMID: 15060748 DOI: 10.1007/s00277-003-0810-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2003] [Accepted: 10/09/2003] [Indexed: 10/26/2022]
Abstract
Allogeneic hematopoietic stem cell transplantation (HSCT) is the only known curative therapy for patients with chronic myeloid leukemia (CML), but is associated with significant morbidity and mortality. The recent introduction of imatinib mesylate (STI-571) and reduced intensity transplant regimens has made the choice of primary treatment for patients with CML increasingly difficult. We have evaluated the outcome of 53 patients who have received allogeneic HSCT from human leukocyte antigen (HLA)-identical sibling donors between October 1985 and March 2002, determined the variables affecting the outcome, and tried to define indications for this aggressive approach. Successful engraftment occurred in 49 (98%) of evaluable patients. Acute graft-versus-host disease (GVHD) of grade II to IV severity was observed in 63% of the evaluable patients whereas the incidence of chronic GVHD was 57.5%. The Kaplan-Meier estimate of survival at 10 years was 54% [95% confidence interval (CI): 38-70%] and 31% (95% CI: 6-56%) for patients with first chronic phase and more advanced diseases, respectively. Multivariate analysis showed that younger age, absence of grade III-IV GVHD, the use of busulphan and cyclophosphamide (BuCy) as preparative regimen, and transplantation performed after January 1992 were factors associated with improved survival. Patients who were 30 years of age or younger who had transplantation done within 1 year after diagnosis during their first chronic phase of disease had a particularly good prognosis, with a probability of surviving 10 years of 72% (95% CI: 52-92%). We conclude that allogeneic HSCT remains a feasible option for Asian patients with CML. The most favorable outcome is observed in younger patients with early phase of the disease.
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Hooi LS, Rozina G, Shaariah MY, Teo SM, Tan CH, Bavanandan S, Rosnawati Y. Pregnancy in patients with renal transplants in Malaysia. THE MEDICAL JOURNAL OF MALAYSIA 2003; 58:27-36. [PMID: 14556324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/27/2023]
Abstract
There were 72 pregnancies in 46 renal transplants (RTs) between 1984 and 2001, 89% from living donors, 11% cadaveric. Mean age at RT was 26.9 +/- 4.3 years and at pregnancy 30.7 +/- 4.7 years. Mean time to pregnancy after RT was 4.5 +/- 3.1 years. 54% were unplanned. 45 (63%) resulted in surviving infants, 37% delivered by Caesarean section. 35% were premature. Mean birth weight was 2.38 +/- 0.57 kg. 64% were on cyclosporine. No patient had an acute rejection during pregnancy; 38% had pre-existing hypertension. Complications include urinary infection (13%), proteinuria (15%) and preeclampsia (15%). Mean serum creatinine before pregnancy was 112.7 +/- 32.6 umol/l, 1 year post-pregnancy it was 119.4 +/- 38.7. The mean time of follow up of mothers is 4.9 +/- 3.5 years. 10 year graft survival was 83% and patient survival 94%.
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Koh LP, Hwang WYK, Chuah CTH, Linn YC, Goh YT, Tan CH, Ng HJ, Tan PHC. Imatinib mesylate (STI-571) given concurrently with nonmyeloablative stem cell transplantation did not compromise engraftment and resulted in cytogenetic remission in a patient with chronic myeloid leukemia in blast crisis. Bone Marrow Transplant 2003; 31:305-8. [PMID: 12621468 DOI: 10.1038/sj.bmt.1703836] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The main obstacles to successful hematopoietic stem cell transplantation for patients with chronic myeloid leukemia (CML) in blast crisis (BC) are increased post-transplant relapse and high treatment-related mortality. We report a patient with CML in BC who was treated initially with imatinib mesylate and was then concurrently treated with a nonmyeloablative stem cell transplant. Successful engraftment of donor cells followed by complete cytogenetic remission was achieved in the absence of severe therapy-related toxicities. This case demonstrates that imatinib mesylate given through nonmyeloablative transplant is a minimally toxic therapeutic approach, which does not compromise engraftment and may result in a favorable outcome in patients with CML in BC.
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Lee ST, Lam TJ, Tan CH. Increased 21-hydroxylase and shutdown of C(17,20) lyase activities in testicular tissues of the grouper (Epinephelus coioides) during 17alpha-methyltestosterone-induced sex inversion. Gen Comp Endocrinol 2002; 126:298-309. [PMID: 12093117 DOI: 10.1016/s0016-6480(02)00005-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The metabolism in vitro of [(3)H]17-hydroxyprogesterone by gonadal tissues of the grouper (Epinephelus coioides) during 17alpha-methyltestosterone (MT)-induced female-to-male sex inversion was examined. In the female phase, C(17,20) lyase, 5beta-reductase, 3alpha/beta-HSD, 20beta-HSD, and 17beta-HSD activities resulted in the biosynthesis of 5beta-pregnans and 5beta-androstanes (including 5beta-androstane-3alpha/beta, 17beta-diol, 3alpha/beta, 17alpha-dihydroxy-5beta-pregnen-20-one, and 5beta-androstane-3,17-dione). In the MT-induced male phase, however, the abrogation of C(17,20) lyase activity and the concomitant activation of 21alpha-hydroxylase/11beta-hydroxylase resulted in the preferential synthesis of polar 21alpha-hydroxlyated 5beta-pregnans (5beta-pregnan-3beta,17alpha,20beta,21alpha-tetrol and 3beta,20beta,21alpha-trihydroxy-5beta-pregnan-3-one) and corticosteroids (11-deoxycortisol and cortisol). Interestingly, synthesis of these 21alpha-hydroxylated 5beta-pregnans and corticosteroids was uniquely compartmentalized in only testicular tissues of the MT-induced males. This study shows that there is selective activation of specific steroidogenic enzymes in the different sexual phases leading to the synthesis of metabolites that may be involved in regulating sex inversion of the grouper.
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Tan EC, Chong SA, Chan AOM, Tan CH. No evidence for association of the T102C polymorphism in the serotonin type 2A receptor with suicidal behavior in schizophrenia. AMERICAN JOURNAL OF MEDICAL GENETICS 2002; 114:321-2. [PMID: 11920856 DOI: 10.1002/ajmg.10190] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Tan CH, Onisong MK, Chiu WKY. The influence of induction technique on intubating conditions 1 min after rocuronium administration: a comparison of a propofol-ephedrine combination and propofol. Anaesthesia 2002; 57:223-6. [PMID: 11879210 DOI: 10.1046/j.0003-2409.2001.02449.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
We conducted a double blind, prospective, controlled trial comparing intubating conditions after induction with a propofol-ephedrine combination or propofol alone, followed by rocuronium. One hundred adult patients were randomly assigned to receive either propofol 2.5 mg x kg(-1) and ephedrine 15 mg in combination or propofol 2.5 mg x kg(-1) given over 30 s, followed by rocuronium 0.6 mg x kg(-1) given over 5 s. Tracheal intubation was performed 1 min later. Jaw relaxation, vocal cord position and diaphragmatic response were used to assess intubation conditions. Tracheal intubation was successful and acceptable in all patients. There was a significantly higher proportion of intubating conditions graded as 'excellent' in the propofol-ephedrine group (84%) than in the propofol group (32%) (p < 0.0001). Vocal cord position and response to intubation were significantly better in the propofol-ephedrine group, although jaw relaxation was similar. Mean arterial pressure was maintained at pre-induction levels in the propofol-ephedrine group. In conclusion, induction with propofol and ephedrine in combination provided significantly better intubating conditions than propofol alone, when followed by rocuronium.
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Pushparaj PN, Tan BK, Tan CH. The mechanism of hypoglycemic action of the semi-purified fractions of Averrhoa bilimbi in streptozotocin-diabetic rats. Life Sci 2001; 70:535-47. [PMID: 11811898 DOI: 10.1016/s0024-3205(01)01423-0] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
In the present study, we have examined the possible mechanism of the hypoglycemic action of the semi-purified fractions of an ethanolic extract of Averrhoa bilimbi Linn (Oxalidaceae) leaves (ABe) in streptozotocin-diabetic male Sprague-Dawley (SD) rats. The ABe was partitioned with water and butanol to yield a butanol-soluble fraction (BuF) and a water-soluble fraction (AF). The AF was further partitioned with ethyl acetate and hexane to obtain ethyl acetate (EF) and hexane (HF) soluble fractions. The hypoglycemic property of each fraction was assessed by the oral glucose tolerance test (OGTT) at a dose of 125-mg/kg-body weight in streptozotocin (STZ)-diabetic rats (STZ 60 mg/kg i.p.). Fractions AF, BuF and the reference drug metformin (500 mg/kg body weight), produced significant blood glucose-lowering effect in the diabetic rats when compared to the vehicle (distilled water). In the long-term study, the diabetic rats were randomly divided into 4 groups and treated orally by gavage with vehicle, AF (125 mg/kg body weight), BuF (125 mg/kg body weight), and metformin (500 mg/kg body weight) respectively twice a day for 14 days. On day 7 and day 14, AF and BuF, like the reference drug, metformin, lowered the fasting blood glucose concentration significantly (P < 0.05) when compared with the vehicle. The serum insulin level was significantly increased in the AF-treated rats only on day 14 when compared to that in the vehicle-treated rats on day zero (P < 0.05). The serum insulin level in BuF-treated rats was also significantly higher (P < 0.05) on both day 7 and day 14 compared to that on day zero. Hepatic glucose-6-phosphatase activity was significantly lower (P<0.05) in AF- and metformin-treated groups, but not in BuF-treated groups, compared to that in vehicle-treated group. However, there was no change in hepatic glycogen content in AF-, BuF- and metformin-treated group compared to the vehicle-treated group. These results indicate that AF is more potent than BuF in the amelioration of hyperglycemia in STZ-diabetic rats and is a potential source for the isolation of new orally active agent(s) for anti-diabetic therapy.
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Tan CH, Tang ZY, Cao ZN, Yin SH. [Determination of trace Sn in geosamples by flow injection on-line co-precipitation hydride generation atomic fluorescence spectrometry]. GUANG PU XUE YU GUANG PU FEN XI = GUANG PU 2001; 21:661-663. [PMID: 12945324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
It is reported that a FI on-line co-precipitation technique for the pre-concentration of trace amount of Sn with the precipitate of Mg(OH)2 as carrier is hyphenated with AFS determination. The co-precipitation is carried out in NaOH medium and the precipitate is collected in a precipitation collector. The precipitate is then dissolved by HCl and reacted with NaBH4, the hydride is transferred directly into the atomizer. The relative standard deviation is 5.15% for 10 determinations of 30 ng.mL-1 Sn and the detection limit of 0.21 ng.g-1 is obtained. The developed method has been applied to the determination of trace Sn in geosamples with satisfactory results.
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Tan EC, Chong SA, Mahendran R, Dong F, Tan CH. Susceptibility to neuroleptic-induced tardive dyskinesia and the T102C polymorphism in the serotonin type 2A receptor. Biol Psychiatry 2001; 50:144-7. [PMID: 11526996 DOI: 10.1016/s0006-3223(01)01076-9] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
BACKGROUND Genetic factors have been implicated in the pathophysiology of the movement disorder tardive dyskinesia, which may involve dopamine-serotonin interaction. Case-control association studies have identified the T102C polymorphism of the 5-HT2A receptor gene as being associated with schizophrenia and responsiveness to clozapine. In this study, we examine the association of this polymorphism in the 5-HT2A receptor gene as a risk factor for developing schizophrenia and tardive dyskinesia from prolonged treatment with neuroleptics. METHODS Ninety-seven healthy control subjects with no history of mental illness and 221 schizophrenic patients (87 with tardive dyskinesia, 134 without) were genotyped by PCR-RFLP. RESULTS Comparison between cases and control subjects revealed no significant association between the C allele and schizophrenia. There was significant difference in allele frequency (p = .044, OR = 1.54 95% CI = 1.02-2.33) between patients who developed tardive dyskinesia and those who did not. Significant difference remains even after adjusting for age and neuroleptic dosage (p = .041) with the odds ratio at 1.64 (95% CI = 1.02-2.62). CONCLUSIONS A genetic variant of the 5-HT2A receptor may be associated with neuroleptic-induced tardive dyskinesia in schizophrenia. Further studies are needed to replicate the finding. The role of 5-HT2A receptor in the etiology of tardive dyskinesia or treatment-resistant schizophrenia should be further investigated.
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Kobayashi Y, Hayashi N, Tan CH, Kishi Y. Toward the creation of NMR databases in chiral solvents for assignments of relative and absolute stereochemistry: proof of concept. Org Lett 2001; 3:2245-8. [PMID: 11440590 DOI: 10.1021/ol010108z] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
[structure: see text] An NMR database approach in a chiral solvent allows us to predict both relative and absolute stereochemistry of an unknown compound without degradation and/or derivatization. N,alpha-Dimethylbenzylamine (DMBA) is a suitable solvent for this purpose. Using the C.5-C.10 portion of oasomycin A, the feasibility and reliability of this approach is demonstrated.
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Lu ZQ, Tan CH, Tao ZY, Xue Q. Acoustical diffraction tomography in a finite form and its computer simulations. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2001; 48:969-975. [PMID: 11477788 DOI: 10.1109/58.935713] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Until now, all acoustical diffraction reconstruction algorithms are in infinite forms. All of these algorithms have disadvantages: severe limitations on scatterers or tedious calculations. In this paper, we present a new reconstruction algorithm in a finite form using the method of formal parameter, which is very simple. This new algorithm gives an exact reconstruction when the amplitude of the scattered wave is smaller than that of the incident wave everywhere. This assumption is much less restrictive than that for the first- and second-order Born approximations. Although this new algorithm is in a finite form, it is still an approximate one when the amplitude of the scattered wave is not smaller than that of the incident wave everywhere. However, it still gives a good reconstruction when the amplitude of the scattered wave is a little greater than that of the incident wave in some area. Some numerical examples have confirmed these conclusions.
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Gwee MC, Tan CH. Problem-based learning in medical education: the Singapore hybrid. ANNALS OF THE ACADEMY OF MEDICINE, SINGAPORE 2001; 30:356-62. [PMID: 11503539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
INTRODUCTION Problem-based learning (PBL) is an innovative educational strategy to enhance student-centred, interactive and integrated learning through intensive small group tutorials. PBL is problem-first learning in which a commonly encountered medical problem serves as the primary focus of and stimulus for learning. Several adaptations have evolved since its implementation at McMaster University in 1969. In 1999, the Singapore medical school implemented PBL as a key feature within its new hybrid curriculum. METHODS The review will focus on the educational implications and impact of the present curriculum reform with emphasis on the implementation of PBL within the new hybrid medical curriculum. RESULTS Our early experience in implementing PBL resembles those of several other "traditional" medical schools, namely, a generally favourable and positive response from staff and students mixed with varying degree of anxiety to change. CONCLUSION Appropriate training and changing the mindsets of staff and students, strong leadership from the Dean and a deep commitment by all concerned are essential to ensure the successful implementation of PBL within a "traditional" medical school. PBL will enhance the quality of medical education and the educational preparation of our students to meet the challenges of future medical practice.
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Chan CY, Tan CH, Chew SP, Teh CH. Laparoscopic fenestration of a simple hepatic cyst. Singapore Med J 2001; 42:268-70. [PMID: 11547965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
Hepatic cysts are usually asymptomatic, most being detected incidentally during imaging. Distinction has to be made between a simple hepatic cyst from more sinister types such as a parasitic cyst and a cyst occurring as part of a neoplastic process. Intervention in a simple hepatic cyst is only indicated when they become symptomatic or when they grow at a rapid rate. Surgery is the mainstay of treatment, with laparoscopic intervention becoming more and more widely accepted. We present here the first case of laparoscopic fenestration of liver cyst performed in our hospital and also review the literature on this modality of treatment.
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Abstract
This paper describes the synthesis of (+)-allopumiliotoxin 323B' (1) using the intramolecular [3 + 2]-cycloaddition reaction of the (Z)-N-alkenylnitrone 4. This synthesis began with (R)-tert-butyl-3-hydroxy-pent-4-enoate [(R)-13] which was obtained by enzymatic resolution with Amano PS lipase. A series of manipulations gave intermediate 17 and in situ coupling with 4-benzoyloxybutanal lead to the (Z)-N-alkenylnitrone 4 which underwent an intramolecular [3 + 2]-cycloaddition reaction to give the isoxazolidine 3 as the major cycloadduct. Isoxazolidine 3 provided the piperidinone 24 which upon diastereofacial selective addition of MeMgBr gave the required tertiary alcohol 25. Formation of the indolizidine core 2 was achieved by an intramolecular S(N)2 reaction. The side chain was assembled from a Wittig reaction between the phosphorane 8 and the enantiomerically pure aldehyde 9. Further modifications afforded the aldehyde 7 which underwent an aldol condensation with the potassium enolate of the indolizidone core 2. Dehydration gave the enone 37 which was converted into the anti-diol 38 by intramolecular hydride reduction. Finally, deprotection of the BOM protecting group gave (+)-allopumiliotoxin 323B' (1).
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Kobayashi Y, Tan CH, Kishi Y. Toward creation of a universal NMR database for stereochemical assignment: complete structure of the desertomycin/oasomycin class of natural products. J Am Chem Soc 2001; 123:2076-8. [PMID: 11456839 DOI: 10.1021/ja004154q] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Chan CY, Tan CH. Ruptured abdominal aortic aneurysms: a personal experience. Singapore Med J 2001; 42:73-6. [PMID: 11358195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/16/2023]
Abstract
Despite advances in surgical technique and peri-operative care, mortality from ruptured abdominal aortic aneurysm presenting to a hospital remains around 50%. This is in contrast to the mortality rate of < 5% for elective repair. In a two and a half year period,the principal surgeon operated on 10 patients with ruptured AAA, with a peri-operative and overall mortality of 30%. One of the ten patients had a ruptured mycotic aneurysm. We present our experience with these patients and also correlate this with recent publications.
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Chong SA, Lee WL, Tan CH, Tay AH, Chan AO, Tan EC. Attempted suicide and polymorphism of the serotonin transporter gene in Chinese patients with schizophrenia. Psychiatry Res 2000; 97:101-6. [PMID: 11166082 DOI: 10.1016/s0165-1781(00)00229-8] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Abnormalities of serotonin synthesis and metabolism may be associated with suicidality. The serotonin transporter gene (5-HTT) is one of the important genes involved in the regulation of serotonin neurotransmission. We examined the association of suicidal behavior in Chinese schizophrenic patients with a functional polymorphism of the promoter region of the 5-HTT gene (5-HTTLPR). The 5-HTTLPR genotype was determined by polymerase chain reaction for 76 suicidal and 262 non-suicidal patients with a diagnosis of schizophrenia (DSM-IV criteria). All subjects were unrelated to each other, and all were Chinese. There was no significant genotypic or allelic association of the 5-HTTLPR polymorphism with history of attempted suicide. From our results, this 5-HTTLPR polymorphism is unlikely to have a major effect on suicidal behavior in Chinese patients with schizophrenia.
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Chong SA, Tan EC, Tan CH, Mahendren R, Tay AH, Chua HC. Tardive dyskinesia is not associated with the serotonin gene polymorphism (5-HTTLPR) in Chinese. AMERICAN JOURNAL OF MEDICAL GENETICS 2000; 96:712-5. [PMID: 11121166 DOI: 10.1002/1096-8628(20001204)96:6<712::aid-ajmg2>3.0.co;2-u] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Neuroleptics are the mainstay of treatment for schizophrenia, but one of the complications is the development of tardive dyskinesia (TD). The pathophysiology of TD may involve dopamine-serotonin interaction. The serotonin transporter participates in the reuptake and termination of serotonin neurotransmission, and the gene that codes for this protein is thus a candidate gene for the development of TD. There is a functional polymorphism in the transcriptional control region of the serotonin transporter gene, and we investigated the association between this polymorphism and TD in Chinese schizophrenic patients. The patients who did not differ in age and sex distribution did not show variation on the rates of TD and Abnormal Involuntary Movements Scale (AIMS) scores with genotypes. Our findings suggest that 5-HTTLPR polymorphism is not a risk factor for TD in Chinese. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 96:712-715, 2000.
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Lee ST, Lam TJ, Tan CH. Corticosteroid biosynthesis in vitro by testes of the grouper (Epinephelus coioides) after 17alpha-methyltestosterone-induced sex inversion. THE JOURNAL OF EXPERIMENTAL ZOOLOGY 2000; 287:453-7. [PMID: 11074458 DOI: 10.1002/1097-010x(20001101)287:6<453::aid-jez7>3.0.co;2-c] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
This study reports the unique compartmentalization of cortisol and 11-deoxycortisol biosynthesis in vitro from [(3)H]17alpha-hydroxyprogesterone (17P) in testicular tissues of groupers after sex inversion induced by 17alpha-methyltestosterone (MT). Before MT implantation, the ovarian tissues produced only nonpolar metabolites. Following sex inversion some 6 months later, synthesis of these nonpolar metabolites was not detectable. Instead, cortisol and 11-deoxycortisol, with yields of about 3% and 14%, respectively, were synthesized together with two other polar metabolites. The corticosteroids and polar metabolites were distinctly nondetectable in ovarian tissues of the control fish throughout the experiment. While the significance of this testicular synthesis of corticosteroids is presently unclear, it could be related to the increased energy demands arising from the reorganization of gonadal tissues during sex inversion.
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Hwang YK, Goh YT, Linn YC, Tan CH, Tan HC. High-dose chemotherapy and autologous stem cell rescue for acute myeloid leukemia remains a safe, effective, and valid option. Transplant Proc 2000; 32:2464-6. [PMID: 11120246 DOI: 10.1016/s0041-1345(00)01745-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Pushparaj P, Tan CH, Tan BK. Effects of Averrhoa bilimbi leaf extract on blood glucose and lipids in streptozotocin-diabetic rats. JOURNAL OF ETHNOPHARMACOLOGY 2000; 72:69-76. [PMID: 10967456 DOI: 10.1016/s0378-8741(00)00200-2] [Citation(s) in RCA: 117] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The present study was designed to investigate the hypoglycemic and hypolipidemic activities of an ethanolic extract of Averrhoa bilimbi Linn. leaves (Oxalidaceae, Common name: Bilimbi) in streptozotocin (STZ)-diabetic rats. The optimal hypoglycemic dose (125 mg kg(-1)) was determined by performing the oral glucose tolerance test (OGTT) in both normal and STZ-diabetic rats. To investigate the effect of repeated administration of an ethanolic extract of Averrhoa bilimbi (ABe) leaves, diabetic rats were treated with vehicle (distilled water), ABe (125 mg kg(-1)) or metformin (500 mg kg(-1)) twice a day for 2 weeks. Like metformin, ABe significantly lowered blood glucose by 50% and blood triglyceride by 130% when compared with the vehicle. ABe also significantly increased the HDL-cholesterol concentrations by 60% compared with the vehicle. ABe thus significantly increased the anti-atherogenic index and HDL-cholesterol/total cholesterol ratio. However, like metformin, ABe did not affect total cholesterol and LDL-cholesterol concentrations, but significantly reduced the kidney lipid peroxidation level. These data show that ABe has hypoglycemic, hypotriglyceridemic, anti-lipid peroxidative and anti-atherogenic properties in STZ-diabetic rats.
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Abstract
Adenosine is known to modulate cell growth in a variety of mammalian cells either via the activation of receptors or through metabolism. We investigated the effect of adenosine on Baby Hamster Kidney (BHK) cell growth and attempted to determine its mechanism of modulation. In wild-type BHK cells, adenosine evoked a biphasic response in which a low concentration of adenosine (1-5 microM) produced an inhibition of colony formation but at higher concentrations (up to 50 microM) this inhibition was progressively reversed. However, no biphasic response was observed in an "adenosine kinase" deficient BHK mutant, "5a", which suggests that adenosine kinase plays an important role in the modulation of growth response to adenosine. Adenosine receptors did not appear to have a role in regulating cell growth of BHK cells. Specific A1 and A2 receptor antagonists were unable to reverse the effect of adenosine on cell growth. Even though a specific A3 adenosine receptor antagonist MRS-1220 partly reversed the inhibition in colony formation at 1 microM adenosine, it also affected the transport of adenosine. Thus adenosine transport and metabolism appears to play the major role in this modulation of cell growth as 5'-amino-5'-deoxyadenosine, an adenosine kinase inhibitor, reversed the inhibition of cell growth observed at 1 microM adenosine. These results, taken together, would suggest that adenosine modulates cell growth in BHK mainly through its transport and metabolism to adenine nucleotides.
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74
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Hwang WY, Goh YT, Tan CH, How GF, Tan HC. Severe acute graft-versus-host disease occurring after syngeneic BMT for AML in a patient not given prior cyclosporin A therapy. Bone Marrow Transplant 2000; 25:205-7. [PMID: 10673682 DOI: 10.1038/sj.bmt.1702115] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
A syndrome akin to graft-versus-host disease in the recipient of syngeneic stem cells is hitherto described as being milder, self-limiting and confined to the skin. It is enhanced by prior cyclosporin A therapy. We describe here a recipient of a syngeneic marrow transplant who did not receive priming with cyclosporin A and yet developed severe and progressive graft-versus-host disease which necessitated and responded to high-dose immunosuppressive therapy. We believe that this is because the conditioning regimen in stem cell transplant acts to reset the immune system enabling it to recognise 'self' antigens. Bone Marrow Transplantation (2000) 25, 205-207.
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75
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Pearson DA, Tan CH, German JB, Davis PA, Gershwin ME. Apple juice inhibits human low density lipoprotein oxidation. Life Sci 1999; 64:1913-20. [PMID: 10353589 DOI: 10.1016/s0024-3205(99)00137-x] [Citation(s) in RCA: 104] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Dietary phenolic compounds, ubiquitous in vegetables and fruits and their juices possess antioxidant activity that may have beneficial effects on human health. The phenolic composition of six commercial apple juices, and of the peel (RP), flesh (RF) and whole fresh Red Delicious apples (RW), was determined by high performance liquid chromatography (HPLC), and total phenols were determined by the Folin-Ciocalteau method. HPLC analysis identified and quantified several classes of phenolic compounds: cinnamates, anthocyanins, flavan-3-ols and flavonols. Phloridzin and hydroxy methyl furfural were also identified. The profile of phenolic compounds varied among the juices. The range of concentrations as a percentage of total phenolic concentration was: hydroxy methyl furfural, 4-30%; phloridzin, 22-36%; cinnamates, 25-36%; anthocyanins, n.d.; flavan-3-ols, 8-27%; flavonols, 2-10%. The phenolic profile of the Red Delicious apple extracts differed from those of the juices. The range of concentrations of phenolic classes in fresh apple extracts was: hydroxy methyl furfural, n.d.; phloridzin, 11-17%; cinnamates, 3-27%; anthocyanins, n.d.-42%; flavan-3-ols, 31-54%; flavonols, 1-10%. The ability of compounds in apple juices and extracts from fresh apple to protect LDL was assessed using an in vitro copper catalyzed human LDL oxidation system. The extent of LDL oxidation was determined as hexanal production using static headspace gas chromatography. The apple juices and extracts, tested at 5 microM gallic acid equivalents (GAE), all inhibited LDL oxidation. The inhibition by the juices ranged from 9 to 34%, and inhibition by RF, RW and RP was 21, 34 and 38%, respectively. Regression analyses revealed no significant correlation between antioxidant activity and either total phenolic concentration or any specific class of phenolics. Although the specific components in the apple juices and extracts that contributed to antioxidant activity have yet to be identified, this study found that both fresh apple and commercial apple juices inhibited copper-catalyzed LDL oxidation. The in vitro antioxidant activity of apples support the inclusion of this fruit and its juice in a healthy human diet.
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