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Abstract
Colonic skip lesions are typically described in Crohn's colitis, but this phenomenon has been recognized in ulcerative colitis (skipped appendiceal involvement), Behcet's colitis, cytomegaloviral colitis, and even in Aeromonas hydrophilia and Histoplasma capsulatum infection. However, skip lesions in typhoid ileo-colitis have not been reported in the English-language literature. We report herein a patient with skip ulcers due to typhoid fever.
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Wong SY, Ngan HY, Chan CC, Cheung AN. Apoptosis in gestational trophoblastic disease is correlated with clinical outcome and Bcl-2 expression but not Bax expression. Mod Pathol 1999; 12:1025-33. [PMID: 10574599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Abstract
Apoptosis has been found to play a crucial role in the pathogenesis and prognosis of many human diseases. The pathogenesis of gestational trophoblastic disease (GTD), which encompasses hydatidiform moles (HMs) and choriocarcinomas (CCAs), is not fully understood. Prognostic indicators of HM have also been scanty. In this study, we investigated apoptotic activity and the expression of two apoptosis regulatory genes, Bcl-2 and Bax, in an attempt to determine the role of apoptosis in GTD. Formalin-fixed paraffin-embedded tissue of 33 normal placentas, 14 spontaneous abortions, 14 partial moles, 34 complete moles, and eight CCAs were examined. Apoptotic activity was assessed by the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling (TUNEL) method. Quantitative assessment of apoptotic index (AI) was calculated as a percentage of TUNEL-positive nuclei. Expression of Bcl-2 and Bax were assessed immunohistochemically. Extensive apoptosis was located in syncytiotrophoblasts, cytotrophoblasts, and villous stromal cells in all HM cases. Apoptosis was detected at a much lower level in spontaneous abortions and normal placentas. Moreover, in normal placentas, TUNEL positive nuclei were exclusively found in syncytiotrophoblasts. AIs were significantly different among various categories of trophoblastic lesions (P < .001) in an ascending order: normal placentas less than spontaneous abortions less than CCAs less than HMs. Furthermore, AIs of those cases that spontaneously regressed was statistically higher than those that developed persistent trophoblastic disease requiring chemotherapy. AIs of trophoblastic lesions in general inversely correlated with Bcl-2 expression (P < .001), but no significant correlation was found between AI and Bax expression (P > .5). We conclude that AI may be a useful prognostic marker for clinical progress of HMs. Bcl-2 expression is probably regulating apoptosis in normal placentas and GTD, whereas Bax expression is not. The difference in AI and Bcl-2 expression between non-molar placentas and HMs offers a potential adjunctive diagnostic tool to distinguish the two entities.
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Wong SY, Ng FH, Kng C. Esophageal variceal ligation by reloading with inexpensive hemorrhoidal O-ring--is an overtube necessary? J Clin Gastroenterol 1999; 29:158-60. [PMID: 10478877 DOI: 10.1097/00004836-199909000-00011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
Abstract
The overtube is the major cause for severe complications during endoscopic variceal ligation with a single-shot ligator. This retrospective study was designed to examine the necessity of the placement of an overtube during elective endoscopic variceal ligation. Thirty-one sessions in 18 patients were analyzed. An overtube was inserted using an over-the-scope technique in 11 sessions (group 1) but was omitted in 20 sessions (group II). The complications, technical difficulties, and operating time were analyzed. Child's grading, the size of the esophageal varices, and the number of rubber bands deployed were comparable in both groups. There was a significantly longer operating time (p < 0.01) and more oropharyngeal injury (p = 0.03) in group I than in group II. Mid esophageal injury, which was associated with resistance in withdrawing the gastroscope from the overtube, occurred in 55% of sessions in group I but in 0% of session in group II. In conclusion, the use of an overtube is associated with more complications, and it can be omitted during elective endoscopic variceal ligation.
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Ng FH, Wong SY, Loo CK, Lam KM, Lai CW, Cheng CS. Prediction of oesophagogastric varices in patients with liver cirrhosis. J Gastroenterol Hepatol 1999; 14:785-90. [PMID: 10482429 DOI: 10.1046/j.1440-1746.1999.01949.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND All patients with liver cirrhosis are recommended for evaluation of oesophagogastric varices (EGV) regularly. This prospective study was designed to develop a predictive model for EGV in cirrhotic patients. METHODS Ninety-two patients were recruited. From all patients studied, the size of palpable spleen, liver chemistry value, platelet count, prothrombin time, diameter of main portal vein and splenic length as assessed by ultrasonography were determined. Upper endoscopy was performed. Oesophageal varices (EV) and gastric varices (GV) were graded (EV, grade 1-4; GV, grade 1-3). In the predictive model, the EGV was classified into two grades (low, grade 1-2 EV or grade 1 GV; high, grade 3-4 EV or grade 2-3 GV). RESULTS There were 53 patients with EGV and 39 patients without EGV as determined by endoscopy. Patients with EGV had a significantly higher degree of ascites and hepatic encephalopathy, lower platelet count and longer splenic length than those without EGV. Low platelet count and presence of ascites were the significant independent predictors for high-grade EGV (concordance rate 0.83). The optimal critical value for the platelet count was 150 x 10(9)/L. Of patients without thrombocytopenia and ascites, 37% had low-grade EGV but none had high-grade EGV, whereas 38 and 35% of patients with thrombocytopenia or ascites had low and high-grade EGV, respectively. Therefore, this predictive model for high-grade varices had a positive and negative predictive value of 35 and 100%, respectively. CONCLUSION Endoscopic screening for EGV was not necessary until thrombocytopenia or ascites occurred.
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Lee AS, Lim IH, Tang LL, Telenti A, Wong SY. Contribution of kasA analysis to detection of isoniazid-resistant Mycobacterium tuberculosis in Singapore. Antimicrob Agents Chemother 1999; 43:2087-9. [PMID: 10428945 PMCID: PMC89423 DOI: 10.1128/aac.43.8.2087] [Citation(s) in RCA: 98] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Genotypic analysis of resistance to isoniazid (INH) in Mycobacterium tuberculosis is complex due to the various genes potentially involved. Mutations in ketoacyl acyl carrier protein synthase (encoded by kasA) were present in 16 of 160 (10%) INH-resistant isolates (R121K [n = 1], G269S [n = 3], G312S [n = 11], G387D [n = 1]). However, G312S was also present in 6 of 32 (19%) susceptible strains. kasA analysis contributed marginally to the performance of INH genotypic testing in Singapore. The significance of kasA polymorphisms in INH resistance should be carefully established.
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Kurup A, Leo YS, Tan AL, Wong SY. Disseminated Penicillium marneffei infection: a report of five cases in Singapore. ANNALS OF THE ACADEMY OF MEDICINE, SINGAPORE 1999; 28:605-9. [PMID: 10561784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Abstract
Penicillium marneffei has emerged as an important opportunistic pathogen in HIV-infected patients in Southeast Asia. We report the first 5 cases of P. marneffei diagnosed in Singapore. All the patients were HIV-infected and were either Thai nationals or had frequently travelled to Thailand. Fever, weight loss, anaemia and papular skin lesions were common clinical manifestations in our patients, all of whom had the organism isolated from blood. Skin biopsy specimens showed histological evidence of P. marneffei in 2 patients. In 1 patient each, the organism grew in cultures of specimens from bone marrow and respiratory secretions. Amphotericin B therapy followed by itraconazole were used in 3 of our 5 patients and was associated with good clinical response and outcome.
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Chang S, Li RC, Chan LS, Wong SY, Zhu M, Chan AT, Raymond K. Netilmicin pharmacokinetics in Hong Kong Chinese cancer patients. Br J Clin Pharmacol 1999; 48:33-5. [PMID: 10383557 PMCID: PMC2014874 DOI: 10.1046/j.1365-2125.1999.00955.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
OBJECTIVES To study the pharmacokinetics of netilmicin in Chinese haematology-oncology patients and to determine the pharmacokinetic differences, if any, between this patient subpopulation of Chinese and Caucasians. METHODS A prospective study was carried out in the adult oncology unit of a major hospital in Hong Kong. During a 6 week period in 1997, all patients commencing on netilmicin therapy were monitored; the patients' demographics, clinical status, netilmicin dose and regimen, and drug administration/blood sampling time were collected. Pharmacokinetic parameters were generated using the USC*PACK package based on specifics of the patients themselves and Caucasians matched for the same patients' parameters using the Bayesian alogrithms. RESULTS A total of 22 patients were enrolled into the study. Twenty-nine sets of levels were drawn, but only 25 sets from 18 patients (86%) were interpretable. The predicted peak (7.47+/-1.46 microg ml-1 ) and trough levels (1.39+/-0.96 microg ml-1 ) generated by USC*PACK were found to be significantly higher than the levels observed (6.01+/-1.14 microg ml-1 and 0.93+/-0.71 microg ml-1, respectively). Netilmicin clearance, volume of distribution and rate of elimination were all significantly higher in this Chinese subpopulation than those predicted for matched Caucasians. Conclusion Alterations in the netilmicin pharmacokinetics observed in our study population might be related to the disease state and/or ethics of the study patient population. Direct application of Caucasian based population pharmacokinetic parameters to this subgroup of Chinese patients may not be appropriate and may result in underdose.
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Inoue T, Tsui J, Wong N, Wong SY, Suzuki F, Kwok YN. Expression of glial cell line-derived neurotrophic factor and its mRNA in the nigrostriatal pathway following MPTP treatment. Brain Res 1999; 826:306-8. [PMID: 10224310 DOI: 10.1016/s0006-8993(99)01254-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Striatal glial cell line-derived neurotrophic factor (GDNF) mRNA levels in both young (2-month old) and old (11-month old) C57BL/6J mice were quantified at 3, 7 and 21 days following 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) treatment. MPTP did not alter the expression of GDNF mRNA in these animals. Immunoreactive staining of GDNF in the substantia nigra and the striatum was also unchanged. In conclusion, MPTP-induced dopaminergic neurotoxicity does not elicit any changes in the expression of endogenous GDNF or its mRNA in the adult mouse brain.
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Ng FH, Chau TN, Cheung TC, Kng C, Wong SY, Ng WF, Lee KC, Chan E, Lai ST, Yuen WC, Chang CM. Cytomegalovirus colitis in individuals without apparent cause of immunodeficiency. Dig Dis Sci 1999; 44:945-52. [PMID: 10235602 DOI: 10.1023/a:1026604529393] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Cytomegalovirus infection is usually reported in immunocompromised patients. In this study, apparently immunocompetent patients with cytomegaloviral colitis were reviewed. Records with a diagnosis of cytomegaloviral colitis from January 1989 to June 1996 were retrieved for analysis. Ten patients were included (median age 70 yr). The major presenting symptoms were diarrhea and hematochezia. Ulceration was the main macroscopic finding. Rectal bleeding was mostly self-limiting. Three patients developed local complications (rectovaginal fistula in two; rectal stricture in one). In the two patients with rectovaginal fistula, lymphocytes subsets and proliferative response were entirely normal. In the other patient, low B lymphocyte count and low response to mitogen were demonstrated. However, the immunoglobulins were not suppressed and rectal biopsies revealed noncaseating granulomas, suggesting activated cell-mediated immunity. In conclusion, a high index of suspicion is crucial for early diagnosis of cytomegaloviral colitis in patients with bloody diarrhea, even though obvious evidence of immunodeficiency is lacking.
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Chang S, Wong SY, Li RC, Chan LS, Chan AT, Zhu M, Raymond K. Utilization and monitoring of aminoglycosides in oncology patients at a Hong Kong government hospital. Ann Pharmacother 1999; 33:646-9. [PMID: 10369635 DOI: 10.1345/aph.18165] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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Tan YK, Lee AS, Khoo KL, Ong SY, Wong SY, Ong YY. Rapid mycobacterial tuberculosis detection in bronchoalveolar lavage samples by polymerase chain reaction in patients with upper lobe infiltrates and bronchiectasis. ANNALS OF THE ACADEMY OF MEDICINE, SINGAPORE 1999; 28:205-8. [PMID: 10497667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Abstract
In areas where tuberculosis is endemic, a positive sputum acid-fast bacilli (AFB) smear is frequently regarded as almost diagnostic of pulmonary tuberculosis (PTB). The main problem arises when the AFB smear is negative. The main aim of this study was to determine the clinical utility of rapid mycobacterial tuberculosis (MTB) detection in bronchoalveolar lavage (BAL) samples by polymerase chain reaction (PCR) in 52 patients who underwent diagnostic bronchoscopy for suspected PTB. These patients had either upper lobe infiltrates (n = 31) or bronchiectasis (n = 21). Mycobacterial culture is usually used as the gold standard of diagnosis. We chose to define active PTB based on positive mycobacterial cultures and/or histological evidence of caseous necrosis and AFB, and/or when there was clinical plus radiological improvement following therapy. We compared AFB smear, respiratory mycobacterial culture, BAL PCR for MTB and clinical active PTB. Four patients who were smear and culture negative had clinical and radiological clearance following anti-tuberculous therapy showing that using mycobacterial culture as a gold standard may have its limitations. When Kappa (a chance-corrected measure of agreement) was calculated for acid-fast bacilli smear and BAL PCR against our definition of active PTB, it was 0.28 (fair agreement) and 0.73 (substantial agreement), respectively. BAL PCR gave a sensitivity, specificity, positive and negative predictive values of 66.7%, 100%, 100% and 88%, respectively, for the group with upper lobe infiltrates. We also demonstrated that BAL for PCR has a good concordance with the final diagnosis of active tuberculosis.
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Wong SY, Guerdoud LM, Cantin A, Speert DP. Glucose stimulates phagocytosis of unopsonized Pseudomonas aeruginosa by cultivated human alveolar macrophages. Infect Immun 1999; 67:16-21. [PMID: 9864190 PMCID: PMC96271 DOI: 10.1128/iai.67.1.16-21.1999] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Glucose has previously been shown to increase the in vitro phagocytosis of unopsonized Pseudomonas aeruginosa by freshly explanted murine peritoneal macrophages (PM) and cultivated alveolar macrophages (AM). This study examined the effect of glucose on the same phagocytosis process in human AM in order to determine whether this phenomenon is conserved among species. Freshly explanted human AM phagocytosed unopsonized P. aeruginosa at a low level (2 bacteria/macrophage/30 min), whereas mouse AM ingested a negligible number of P. aeruginosa (0.01 bacterium/macrophage/30 min). Glucose had no effect on this or other phagocytic processes in freshly explanted mouse or human AM. However, following in vitro cultivation for 72 h, human AM phagocytosed three to four times more unopsonized P. aeruginosa than did freshly explanted cells, but only in the presence of glucose. This glucose-inducible phagocytic response had also been observed in cultivated murine AM. Although similar increases were also detected for the phagocytosis of latex particles and complement-coated sheep erythrocytes by cultivated human AM, these processes were not glucose dependent. The lack of response to glucose in freshly explanted mouse AM was attributed to insufficient glucose transport; however, freshly explanted human AM exhibited significant facilitative glucose transport activity that was inhibitable by cytochalasin B and phloretin. Taken together, these results suggest that the process of glucose-inducible phagocytosis of unopsonized P. aeruginosa is conserved among macrophages from different species, including humans, and that AM, but not PM, required cultivation for this glucose effect to occur. Glucose transport by AM appears to be necessary but not sufficient for phagocytosis of unopsonized P. aeruginosa.
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Foo E, Sim R, Lim HY, Chan ST, Leo YS, Wong SY. Abdominal surgery in human immunodeficiency virus (HIV) infected patients--early local experience. ANNALS OF THE ACADEMY OF MEDICINE, SINGAPORE 1998; 27:759-62. [PMID: 10101544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
The prevalence of human immunodeficiency virus (HIV) infection is increasing in Singapore. The surgical experience, however, remains limited. A retrospective review of 13 HIV-positive patients requiring abdominal surgery within Singapore was done. There were 4 females and 9 males with age ranging from 21 to 44 years. Operations included appendicectomy, colectomy, splenectomy, intestinal bypass, gastrostomy and exploratory laparotomy. Pathologic findings directly related to HIV infection were found in two-fifths (5 out of 13) of these patients. A low CD4+ count or signs of full-blown acquired immunodeficiency syndrome (AIDS) were not associated with a higher likelihood of HIV-related pathology; neither did it preclude a successful outcome. There were 2 early postoperative deaths, both with HIV-related pathology. Five of our patients who survived their abdominal surgery died on follow-up with a median survival of 17 months. In patients with typical surgical problems, e.g. appendicitis and torsion of the ovary, early surgery allows for rapid recovery similar to normal surgical patients. Care of these patients is best provided by surgeons with experience and interest in this condition together with infectious diseases physicians. Even palliative surgery offers a respite from acute and often severe problems and improves the quality of life significantly. Two patients with AIDS presented with sepsis and diffuse abdominal tenderness. Subsequent laparotomy revealed only primary bacterial peritonitis. For patients with AIDS and non-localizing abdominal signs, alternative non-invasive diagnostic modalities such as computed tomographic (CT) scan should be considered.
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Ng FH, Wong SY, Kng C, Chow SL, Lai KC, Ng WF. Effect of simethicone on the accuracy of the rapid urease test. Eur J Gastroenterol Hepatol 1998; 10:851-4. [PMID: 9831407 DOI: 10.1097/00042737-199810000-00007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
OBJECTIVE Simethicone, which is a principal ingredient in the defoaming agent used during gastroscopy, can inhibit the growth of Helicobacter pylori (MIC, 64-128 mg/l). This prospective study was designed to evaluate the in vivo and in vitro effects of simethicone on the accuracy of the rapid urease test (RUT). METHODS In the in vivo study, three sets of gastric biopsies (two from the antrum, and one from the corpus) were taken from 75 patients. The first set was examined histologically, and the second set was used for the RUT (pre-simethicone RUT). Then, 25 ml simethicone (1200 mg/l) was introduced into the stomach for a contact time of 1 min. A third set of gastric biopsies was taken for the RUT (post-simethicone RUT). In the in vitro clinical study, 41 patients were recruited. The first set of gastric biopsies was used for the RUT (pre-incubation RUT). The second set was incubated in 1 ml of simethicone for 5 min before being used for the RUT (post-incubation RUT). In the spectrophotometric study, urease activity before and after incubation in simethicone for 5 min was quantified in 12 patients by measuring the absorbance at 560 nm. RESULTS Reading at 15 min, the concordance rate between the pre-simethicone and post-simethicone RUT was 98%. In the in vitro clinical study, the concordance rate between the pre-incubation and post-incubation RUT was 97%. The spectophotometric study showed a significant reduction of 43% in urease activity after incubation in simethicone. CONCLUSION The application of a defoaming agent containing simethicone does not affect the accuracy of the RUT. However, simethicone modestly suppresses urea hydrolysis.
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Ho PL, Luk WK, Wong SY, Seto WH, Lo YC, Yuen KY. Pseudobacteremia with amoxycillin-clavulanic acid-resistant Escherichia coli traced to cross-contamination during blood culture processing. Chin Med J (Engl) 1998; 111:570-6. [PMID: 11245082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023] Open
Abstract
Escherichia coli has seldom been reported to cause pseudobacteremia. The investigation of an outbreak of amoxycillin-clavulanic acid-resistant E. coli pseudobacteremia is described. Seventeen cases occurred over a five-day period. The source of the E. coli was traced to the blood culture specimen of a patient (index patient) with genuine bacteremia as a result of urinary tract infection. The other 16 case-patients had pseudobacteremia which was found to be the result of cross-contamination during subculture of blood specimens. The E. coli strain was carried over from the culture bottle of the index patient, through the contaminated gloved hands of a technician to the culture bottles of the other 16 cases. Although the pseudobacteremia occurred over a five-day period, they all resulted from cross-contamination during blood culture processing within one day. An early outbreak investigation was prompted by the unusual finding of amoxycillin-clavulanic acid resistance in the case E. coli isolates in a short period. The relatedness of the E. coli strains from the 17 cases was confirmed by arbitrary-primed polymerase chain reaction. Clinicians should be alerted to the possibility of a blood E. coli isolate being a contaminant despite its predominant role as a true pathogen.
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Boudville IC, Wong SY. Health care systems in transition. II. Singapore, Part II. The current status of HIV-AIDS. JOURNAL OF PUBLIC HEALTH MEDICINE 1998; 20:23-8. [PMID: 9602444 DOI: 10.1093/oxfordjournals.pubmed.a024712] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Liou SC, Chen C, Wong SY, Wong KM. Ventricular tachycardia after oxytocin injection in patients with prolonged Q-T interval syndrome--report of two cases. ACTA ANAESTHESIOLOGICA SINICA 1998; 36:49-52. [PMID: 9807850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Oxytocin is widely used in obstetric settings to stimulate uterine contraction and prevent postpartum hemorrhage. Its adverse effects which include transient hypotension and increase heart rate could be life-threatening in patients with fixed cardiac output or hypotension resulting from hemorrhage. We reported two cases suspected to have preexisting prolonged Q-T interval syndrome (PQTS) who developed ventricular tachycardia immediately after intravenous injection of oxytocin. Anesthetic management of and use of oxytocic agents in patients with PQTS were discussed.
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Yick LW, Wu W, So KF, Wong SY. Time course of NOS expression and neuronal death in Clarke's nucleus following traumatic injury in adult rat spinal cord. Neurosci Lett 1998; 241:155-8. [PMID: 9507944 DOI: 10.1016/s0304-3940(98)00020-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The objective of this study was to investigate the influence of the length of the remaining axons on neuronal survival following axonal injury in the adult rat spinal cord. The relationship between the expression of nitric oxide synthase (NOS) and neuronal death was also studied. The time course of NOS expression and neuronal loss was observed in Clarke's nucleus at segment L1 following hemisection of the cord at either segment C3, T1, or T11. NOS-positive neurons were first observed 3 days after injury, rising significantly after 5 days, and reaching a maximum by 10-20 days post-injury. During the same period the number of neurons surviving in the nucleus decreased. The decrease began at 3 days, rapidly decreased after 5 days, and reached a minimum by 40 days post-injury. Among the three lesioned groups, the highest percentage of NOS expression and neuronal loss was observed in the group with lesions at T11, while the lowest percentage was in the group with lesions at C3. Although the time course of neuronal loss varied following lesion at different spinal levels, in all cases the majority of neurons in Clarke's nucleus had degenerated by 40 days after axotomy.
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Ng FH, Wong SY, Ng WF. Storage temperature of the unbuffered rapid urease test. Am J Gastroenterol 1997; 92:2230-1. [PMID: 9399759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
OBJECTIVES The unbuffered rapid urease test (RUT) is an accurate, rapid, and inexpensive method for detecting Helicobacter pylori. However, it is generally recommended that the reagent be prepared daily. This prospective study was undertaken to evaluate the shelf life of our unbuffered RUT when stored at 4 and -20 degrees C. METHODS Ninety-five patients were studied. Three sets of antral (X2) and body (X1) biopsy samples were taken from each patient. The samples were subjected to histological examination, with the RUTs stored at 4 and -20 degrees C. The RUT tubes were examined at 1 and 15 min. RESULTS Fifty-six patients (59%) were infected with H. pylori as defined by histological examination. The reagent was classified according to storage time (group I, < or = 5 days; group II, > 5 days). The mean (SD) storage time of group I (n = 59) and group II (n = 36) was 3.2 (1.4) and 9.9 (5.0) days, respectively. At 15 min, the sensitivity of our RUT stored at 4 degrees C was significantly higher in group I than in group II (92 vs 47%). On the other hand, the sensitivity of our RUT stored at -20 degrees C remained consistently high in both groups (15 min: group I, 92%; group II, 100%). Our RUTs stored at 4 and -20 degrees C were highly specific in both groups. CONCLUSIONS Our RUT remains highly sensitive and specific when it is stored at 4 degrees C for up to 5 days. When the RUT is expected to be stored for a longer period of time, the bottles should be frozen at -20 degrees C.
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Lee CC, Leo YS, Snodgrass I, Wong SY. The demography, clinical manifestations and natural history of human immunodeficiency virus (HIV) infection in an older population in Singapore. ANNALS OF THE ACADEMY OF MEDICINE, SINGAPORE 1997; 26:731-5. [PMID: 9522969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
In this retrospective study, we report 43 cases (41 males and 2 females) of human immunodeficiency virus (HIV) infection in the Singapore population aged 50 years and above at first presentation. We found an increasing proportion of these older individuals among our HIV-seropositive patients; from 4.8% in 1991 to 16.7% by mid-1996. The mean age at presentation was 59.2 years (range 50 to 75 years). They were mainly heterosexuals (93%) and the majority (79.1%) were previously or currently married. Thirty-six (83.7%) patients had multiple sexual exposures to commercial sex workers. Nearly all had acquired the infection through the sexual route. The majority (76.7%) were symptomatic at presentation. Common clinical presentations were weight loss (72%), respiratory symptoms (60%) and oral candidiasis (56%). More than half (58.1%) of the patients had acquired immunodeficiency virus (AIDS) at the time of first presentation with a low median CD4 count of 17 cells/mm3. Pneumocystis carinii pneumonia and tuberculosis were the common AIDS-defining diseases. Survival in patients presenting with AIDS (median survival 3 months) is poorer compared to younger HIV-seropositive patients (< 50 years; median survival 1 year). No increase in age-related infection or malignancy was seen. Common causes of death were pneumonia and septicaemia. Physicians should consider HIV infection in older patients particularly when he/she presents with unexplained weight loss, respiratory symptoms and oral candidiasis. A history of high-risk sexual behaviour must be sought in all patients, including the elderly.
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Lee AS, Tang LL, Lim IH, Ling ML, Tay L, Wong SY. Lack of clinical significance for the common arginine-to-leucine substitution at codon 463 of the katG gene in isoniazid-resistant Mycobacterium tuberculosis in Singapore. J Infect Dis 1997; 176:1125-7. [PMID: 9333184 DOI: 10.1086/517320] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
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Wong SY, Goh KT. Emerging infections: why we must be concerned. ANNALS OF THE ACADEMY OF MEDICINE, SINGAPORE 1997; 26:535-7. [PMID: 9494654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Boudville IC, Wong SY, Snodgrass I. Drug-resistant tuberculosis in Singapore, 1995 to 1996. ANNALS OF THE ACADEMY OF MEDICINE, SINGAPORE 1997; 26:549-56. [PMID: 9494657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Singapore's tuberculosis incidence of 49 to 57 per 100,000 population for 1987 to 1996 presents a picture that is intermediate between developed and developing countries. The proportion of drug-resistant isolates has remained stable at 4.3% to 5.5% from 1992 to 1996 despite rising HIV rates. From 1995 to 1996, of the 199 consecutive drug-resistant isolates at the Central Tuberculosis Laboratory, 66% were mono-resistant, 22% dual-resistant and 12% resistant to more than two drugs. Isoniazid resistance was most prevalent, being found in 72% of isolates, followed by streptomycin resistance in 45%. Resistance to isoniazid and streptomycin (21%) was more common than to isoniazid and rifampicin, i.e. multidrug resistance (MDR) (14%). The small numbers indicated by the low overall prevalence of resistance and the predominance of single-drug resistance support the current initial choice of the standard short course with its three-drug initial phase. Of the 170 cases with matching National Tuberculosis Registry data, 72% of drug-resistant cases represented initial and 28% acquired resistance; testifying to the effectiveness of present day treatment regimens in suppressing resistance when compliance is assured. Case-control analysis using 244 drug-sensitive controls randomly selected from notifications in 1995 to 1996 showed an odds ratio for drug-resistance between subjects with a previous history and no previous history of tuberculosis of 2.47 (95% CI 1.40 to 4.37; P = 0.0007). With each increment in the number of episodes of tuberculosis experienced, there was a trend of resistance to progressively more drugs (P = 0.000004). This association remained even when a logistic regression model including all predictor variables was fitted. No associations were found with age, history of contact with tuberculosis, cavitary disease and, most notably, with human immunodeficiency virus infection. This study reaffirms that a history of previous tuberculosis should increase clinicians' index of suspicion for drug resistance, the urgency with which culture and sensitivity results are sought and the vigour with which patients are followed-up and compliance monitored.
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Abraham G, Leo YS, Singh M, Wong SY. A case report of visceral leishmaniasis in Singapore. ANNALS OF THE ACADEMY OF MEDICINE, SINGAPORE 1997; 26:713-6. [PMID: 9494684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Visceral leishmaniasis (Indian kala-azar) caused by infection due to the protozoan Leishmania donovani is endemic in the Indian subcontinent and adjoining regions. Prolonged fever, hepatosplenomegaly, anaemia and pancytopenia, in the appropriate setting, are important clinical markers towards the diagnosis. Diagnosis is established by blood film or bone marrow examination for Leishman Donovan (LD) bodies and/or culture. Treatment with sodium stibogluconate, pentamidine isethionate or even amphotericin B is usually successful. We report the first case of culture-proven visceral leishmaniasis in Singapore, in a 30-year-old Bangladeshi worker who presented with pyrexia of unknown origin (PUO). He had the classical constellation of symptoms and signs as mentioned above. Diagnosis was confirmed by culture on the Novy, NcNeal and Nicolle (NNN) medium. He was successfully treated with 20 days of pentamidine isethionate daily infusions at a dose of 2 mg/kg/day.
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Tan BH, Wong GC, Lam MS, Ang BS, Wong SY. Clinical characteristics and natural history of human immunodeficiency virus infected patients seen at a general hospital in Singapore. ANNALS OF THE ACADEMY OF MEDICINE, SINGAPORE 1997; 26:566-74. [PMID: 9494659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The number of patients with human immunodeficiency virus (HIV) infection in Singapore has risen over the years. A considerable proportion of them present with acquired immunodeficiency syndrome (AIDS). In this study, we document the clinical characteristics and natural history of a consecutive series of 50 patients who were found to have HIV infection when they were seen at a tertiary care hospital. The majority were in the 30 to 49 age group and the most common mode of acquisition was heterosexual contact. The patients presented with a variety of symptoms to 11 different clinical departments. Fifty-eight per cent of the patients had AIDS-defining illnesses at presentation, with Pneumocystis carinii pneumonia being the most common. On follow-up, the most frequently occurring opportunistic infection that developed was Cytomegalovirus retinitis. Most patients had multiple subsequent admissions--for both AIDS-defining and non AIDS-defining conditions. The median CD4 count of the cohort at presentation was 72/mm3. The median survival was 399 and 822 days in those who had and those who did not have an AIDS-defining illness at presentation, respectively. Mortality was most commonly attributed to pneumonia. HIV infection has protean manifestations and patients may present to various specialty departments; hence, doctors need to be aware of the spectrum of disease in order to make a diagnosis.
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