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Marzo-Ortega H, McGonagle D, Jarrett S, Haugeberg G, Hensor E, O'connor P, Tan AL, Conaghan PG, Greenstein A, Emery P. Infliximab in combination with methotrexate in active ankylosing spondylitis: a clinical and imaging study. Ann Rheum Dis 2005; 64:1568-75. [PMID: 15829577 PMCID: PMC1755262 DOI: 10.1136/ard.2004.022582] [Citation(s) in RCA: 128] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
OBJECTIVE To examine the efficacy and safety of infliximab combined with methotrexate compared with methotrexate alone in the treatment of ankylosing spondylitis (AS) using MRI and DXA to monitor its impact on bone. METHODS In this single centre study 42 subjects with active AS were treated with methotrexate and were randomly assigned, in a ratio of 2:1, to receive five infusions of either 5 mg/kg infliximab or placebo over 30 weeks. The primary outcome was improvement in disease activity as shown by the BASDAI at week 30. MRI was used to assess the effect of treatments on sacroiliac and spinal enthesitis/osteitis and DXA to monitor bone mineral density. RESULTS Both therapeutic agents were well tolerated with no dropouts due to adverse events. A significantly greater improvement in mean BASDAI score was seen in the infliximab arm at week 10 (p = 0.017) than in the placebo arm, but this was not maintained by week 30 (p = 0.195), 8 weeks after the last infusion, at which stage disease flares were reported by some subjects. MRI showed that the mean number of lesions resolving for each subject from week 0 to week 30 was significantly greater in the combination group than in the methotrexate monotherapy group (p = 0.016). CONCLUSIONS Infliximab in combination with methotrexate was a safe and efficacious treatment in AS over 6 months and was associated with significant regression in enthesitis/osteitis as determined by MRI. However, disease flares were reported 8 weeks after the last infusion, indicating that addition of methotrexate failed to extend the infliximab dosing interval.
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Margallo-Lana M, Morris CM, Gibson AM, Tan AL, Kay DWK, Tyrer SP, Moore BP, Ballard CG. Influence of the amyloid precursor protein locus on dementia in Down syndrome. Neurology 2004; 62:1996-8. [PMID: 15184603 DOI: 10.1212/01.wnl.0000129275.13169.be] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND The amyloid precursor protein (APP) locus on chromosome 21 influences the development of Alzheimer disease. METHOD The authors investigated the relationship between a tetranucleotide repeat on intron 7 of the APP gene and the age at onset of dementia in Down syndrome (DS). RESULTS There was a 13-year difference in the age at onset of dementia in DS associated with the number of tetranucleotide repeat alleles in APP. CONCLUSION APP is an important locus predicting the age at onset of dementia in people with Down syndrome.
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Wakefield RJ, McGonagle D, Tan AL, Evangelisto A, Emery P. Ultrasound detection of knee patellar enthesitis. Ann Rheum Dis 2004; 63:753; author reply 753-4. [PMID: 15140792 PMCID: PMC1755034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
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Tan AL, Marzo-Ortega H, O'Connor P, Fraser A, Emery P, McGonagle D. Efficacy of anakinra in active ankylosing spondylitis: a clinical and magnetic resonance imaging study. Ann Rheum Dis 2004; 63:1041-5. [PMID: 15066864 PMCID: PMC1755137 DOI: 10.1136/ard.2004.020800] [Citation(s) in RCA: 119] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
OBJECTIVE To determine the efficacy of anakinra, an interleukin 1 receptor antagonist in active ankylosing spondylitis (AS), and to investigate the effect of anakinra treatment on spinal enthesitis/osteitis using magnetic resonance imaging (MRI). METHODS A 3 month open label study of anakinra (100 mg subcutaneous injection daily) was carried out in nine patients with active AS who had back pain and an increased acute phase response, and who had failed to respond to at least one non-steroidal anti-inflammatory drug. Clinical assessment included the Bath AS Functional Index (BASFI), Bath AS Disease Activity Index (BASDAI), and AS Quality of Life (ASQoL) before and after treatment. Fat suppressed MRI of the spine and sacroiliac joints was performed with a 1.5 T scanner at baseline and at 3 months to determine the effect of treatment on spinal enthesitis/osteitis. RESULTS Significant improvement was found in the BASFI (median baseline 5.88, 3 months 3.63, p = 0.021), BASDAI (median baseline 5.63, 3 months 3.48, p = 0.028), ASQoL (median baseline 12, 3 months 8, p = 0.011) and laboratory measures reflecting inflammation, with C reactive protein (median baseline 31 mg/l, 3 months 17 mg/l, p = 0.036) and erythrocyte sedimentation rate (median baseline 19 mm/1st h, 3 months 15 mm/1st h, p = 0.008) also showing significant improvement. Six patients (67%) achieved the Assessments in AS (ASAS) Working Group criteria of 20% improvement. Of the 38 regions of enthesitis/osteitis determined by MRI at baseline, 23 (61%) either improved or regressed completely. CONCLUSIONS This open label pilot study suggests that anakinra is effective in controlling the clinical manifestations of AS. The clinical response was reflected by an improvement in MRI determined spinal enthesitis/osteitis.
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Tan AL, Holdsworth J, Pease C, Emery P, McGonagle D. Successful treatment of resistant giant cell arteritis with etanercept. Ann Rheum Dis 2003; 62:373-4. [PMID: 12634246 PMCID: PMC1754511 DOI: 10.1136/ard.62.4.373] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Maw A, Concepcion R, Eu KW, Seow-Choen F, Heah SM, Tang CL, Tan AL. Prospective randomized study of bacteraemia in diathermy and stapled haemorrhoidectomy. Br J Surg 2003; 90:222-6. [PMID: 12555300 DOI: 10.1002/bjs.4057] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND The incidence and consequences of bacteraemia associated with diathermy and stapled haemorrhoidectomy have not been studied previously. METHODS Two hundred and five healthy patients randomized to stapled haemorrhoidectomy or diathermy haemorrhoidectomy had perioperative blood cultures taken. The clinical sequelae of bacteraemia and complications of surgery were assessed prospectively. RESULTS Six patients were excluded for protocol violations. Eleven (11 per cent) of 101 patients with stapled and five (5 per cent) of 98 who had diathermy haemorrhoidectomy had positive blood cultures for organisms after haemorrhoidectomy, predominantly anaerobes commonly found within the bacterial flora of the anorectum (P = 0.19). Transient postoperative pyrexia in several patients did not correlate with detected bacteraemia and settled spontaneously without treatment. There were no serious complications from either operative technique, and no clinical consequences from proven bacteraemia. CONCLUSION Transient bacteraemia may complicate surgical haemorrhoidectomy but has no serious clinical consequences for healthy adults.
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Loy AHC, Tan AL, Lu PKS. Microbiology of chronic suppurative otitis media in Singapore. Singapore Med J 2002; 43:296-9. [PMID: 12380726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/26/2023]
Abstract
The objective of the study was to study the microflora and the antibiograms of patients with chronic suppurative otitis media (CSOM) in Singapore. Ninety patients with CSOM were prospectively studied. They had chronic ear discharge and had not received antibiotics for the previous five days. Swabs were taken, and cultured for bacteria. Antibiotic testing was done using modified Kirby Bauer disk diffusion method. In addition to the usual antibiotics, the three most common topically available antibiotics (chloramphenicol, gentamicin and neomycin) were tested. There were 135 positive cultures for organisms from the 90 patients. The most common causal organisms isolated were Pseudomonas aeruginosa (33.3%) and Staphylococcus aureus (33.3%) followed by coagulase negative Staphylococcus (21.1%). Fungi accounted for 8.8% of isolates while 6.6% were anaerobes. Of the three antibiotics commonly available as topical eardrops, gentamicin has the highest susceptibility rate (82.6%), followed by neomycin (67.8%) and chloramphenicol (62.8%).
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Abstract
We describe here two cases of Cryptococcus neoformans var. gattii meningitis that occurred in Singapore. This variety of Cryptococcus neoformans differs from the more widely known C. n. var. neoformans in its ecology and epidemiology. Infections with this variety are still rare in Singapore.
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Oh HM, Tan AL. Shigella septicaemia in adults: report of two cases and mini-review. ANNALS OF THE ACADEMY OF MEDICINE, SINGAPORE 2001; 30:668-70. [PMID: 11817302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
INTRODUCTION We report 2 cases of Shigella septicaemia in adult patients. CLINICAL PICTURE Two 57-year-old women presented with non-bloody diarrhoea and fever. The first patient was an inmate of a long-term care facility who was schizophrenic and the second patient was a diabetic who recently travelled to Medan, Indonesia. Both patients were febrile, hypotensive and dehydrated. The first patient was neutropenic, thrombocytopenic and had acute renal failure. Blood cultures yielded Shigella flexneri and stool cultures gave negative results for both patients. TREATMENT Rehydration and intravenous ceftriaxone were instituted. OUTCOME The patients' symptoms and hypotension resolved. CONCLUSION Appropriate antibiotics can decrease the severity and duration of Shigella septicaemia.
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Tan AL, Unruh HW, Mink SN. Lung volume reduction surgery for the treatment of severe emphysema: a study in a single Canadian institution. Can J Surg 2000; 43:369-76. [PMID: 11045096 PMCID: PMC3695144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023] Open
Abstract
OBJECTIVE To evaluate lung volume reduction surgery (LVRS) and its effectiveness in improving pulmonary function, exercise capacity and quality of life in a population of emphysema patients referred to and screened in a single centre. DESIGN A prospective case series. SETTING A Canadian tertiary care hospital. PATIENTS Patients with severe emphysema, significant dyspnea and impaired exercise capacity interfering with quality of life. INTERVENTIONS Bilateral LVRS was performed through a median sternotomy. MAIN OUTCOME MEASURES Pulmonary function tests (preoperative forced expiratory volume in the first second [FEV1], residual volume [RV]), 6-minute walk (6 MW) distance, quality of life (Medical Outcomes Study 36-item short-form health survey) and degree of dyspnea (Medical Research Council of Great Britain dyspnea scale and the baseline and transitional dyspnea indices) were assessed before LVRS and at 6 and 12 months after. RESULTS Fifty-seven patients were assessed for LVRS, of whom 10 were selected for surgery. Homogeneous distribution of disease was the most common reason for exclusion. Of the 10 patients operated upon, 1 died of acute cor pulmonale on the fourth postoperative day and 1 died of recurrent exacerbations of chronic obstructive pulmonary disease and chronic respiratory failure at 315 days postoperatively. In the surviving patients, the mean preoperative FEV1 increased from 0.70 L before surgery to 0.90 L at 1 year, with a mean relative increase of 33.4%. The mean RV decreased from 5.57 L to 4.10 L, with a mean relative decrease of 27.6%. The 6 MW distance increased from 302.7 m to 356.9 m at 1 year, with a mean relative increase of 21.6%. Quality of life and degree of dyspnea were improved significantly at 1 year after LVRS. Of the 5 patients on oxygen at home before surgery, 4 were able to reduce their requirements but not to discontinue oxygen. CONCLUSIONS LVRS is an effective palliative treatment for dyspnea and poor exercise tolerance in highly selected patients. Although the duration of palliation is unknown, our results show that improvements in pulmonary function, exercise, quality of life and degree of dyspnea are preserved over the first year. Only a minority of the patients screened were eligible for surgery. The 2 deaths in our series emphasize the need for even further delineation of selection criteria.
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Khor CJ, Fock KM, Ng TM, Teo EK, Sim CS, Tan AL, Ng A. Recurrence of Helicobacter pylori infection and duodenal ulcer relapse, following successful eradication in an urban east Asian population. Singapore Med J 2000; 41:382-6. [PMID: 11256345] [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]
Abstract
We aimed to determine the rate of Helicobacter pylori (HP) recurrence and duodenal ulcer relapse in patients of a hospital in Singapore over a period of at least one year from the time of eradication. Ninety-six consecutive duodenal ulcer patients with biopsy-proven HP eradication and healed ulcer were seen at 3-month intervals, and follow-up endoscopy was performed when dyspepsia recurred, at the end of one year after eradication, or at the time of recall if the patient had been lost to follow-up. HP status was determined by antral and corpus biopsies and by antral cultures. Sixty-five had been given triple therapy, and 31 received dual therapy with omeprazole + amoxycillin or clarythromycin. Median time to follow-up endoscopy was 12 months. Six patients (6.25%) were positive for HP infection after eradication. Recurrence of HP infection was detected at 9 and 10 months after confirmation of HP eradication in two patients, and at between 13 and 20 months in the remaining four. Two of these had recurrent duodenal ulcer; all but one had erosive duodenitis. Two other patients had recurrent duodenal ulcer despite absence of HP reinfection; they admitted to taking low-dose aspirin. It was concluded that the recurrence of HP infection is low at the end of one year after successful eradication therapy in this urban East Asian population. Ulcer relapse occurred in 4.17% (4/96) of patients, and was associated with recurrent HP infection or NSAID exposure.
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Tan AL, Jones R, Mcpherson G, Rowan D. Audit of a multidisciplinary vulvar clinic in a gynecologic hospital. THE JOURNAL OF REPRODUCTIVE MEDICINE 2000; 45:655-8. [PMID: 10986684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
OBJECTIVE To perform a five-year retrospective audit of all new patients referred to a tertiary vulvar referral service. STUDY DESIGN A review was made of the records of all new clients who attended the vulvar clinic between 1993 and 1997. Information was entered into a database and analyzed. RESULTS Four hundred seventeen women were seen in the study period. Their ages ranged from 8 to 94 years (mean, 48.5). The most common symptoms were pruritus (44.8%), soreness (28.6%) and irritation (24.2%). Striking features were the poorly defined and lengthy histories and multiple symptomatology. Biopsies were performed in 61% of cases. Histologic diagnoses included vulvar intraepithelial neoplasia (VIN), 18.5%; nonneoplastic epithelial disorders, 16.8%; and carcinoma, 8.1%. Clinical diagnoses included dermatitis in 10% and normal vulva in 7.7%. The remaining cases represented a wide variety of dermatologic, pain and gynecologic conditions. There was a 95% correlation between the clinical and histologic diagnosis of VIN and 87% in lichen sclerosus. In 64.7% of women, treatment resulted in an improved outcome, 13.7% reported no improvement, and 1.6% cases deteriorated during treatment; 19.9% were lost to follow-up. CONCLUSION Provision of a multidisciplinary vulvar clinic in a tertiary setting provides an invaluable service for both primary and secondary clinical practitioners. The increasing demand for our services has created lengthy waiting times. The chronic nature of many vulvar diseases results in long-term follow-up of many women. Patient selection bias has developed as a consequence of the interests of the clinicians involved.
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Teo EK, Fock KM, Ng TM, Khor CJ, Tan AL. Metronidazole-resistant Helicobacter pylori in an urban Asian population. J Gastroenterol Hepatol 2000; 15:494-7. [PMID: 10847434 DOI: 10.1046/j.1440-1746.2000.02160.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
BACKGROUND Helicobacter pylori eradication is the mainstay in the treatment of H. pylori-associated peptic ulcer disease. Metronidazole is an important component in most eradication regimens. However, the presence of metronidazole-resistant H. pylori adversely affects the efficacy of such regimens. We aimed to study the prevalence of metronidazole resistance in our population, and the factors associated with its presence. METHODS AND RESULTS From September 1993 to September 1996, 459 H. pylori isolates were collected and analysed. The overall resistance rate was 62.7%. The rate was significantly higher among women compared with men (P < 0.05). When the results were analysed according to each year, there was a significant increase in the resistance rate from 50.5% in the first year to 72.7% in the third year (P = 0.0039). CONCLUSIONS There was a significant rise in the prevalence of metronidazole resistance over a 3-year period. The presence of metronidazole resistance adversely affects the eradication rates of nitroimidazole-based regimens. Hence, in a population with a high prevalence of metronidazole resistance, the use of non-nitroimidazole-based therapy may be more efficacious. This information on resistance rates is important for the empirical choice of antibiotic against H. pylori in a population.
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Ng TM, Fock KM, Khor JL, Teo EK, Sim CS, Tan AL, Machin D. Non-steroidal anti-inflammatory drugs, Helicobacter pylori and bleeding gastric ulcer. Aliment Pharmacol Ther 2000; 14:203-9. [PMID: 10651661 DOI: 10.1046/j.1365-2036.2000.00679.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/08/2022]
Abstract
BACKGROUND Helicobacter pylori infection and NSAID usage are considered to be independent risk factors for gastric ulcer (GU). Whether they interact to influence the risk of bleeding in GU is unclear. AIM To determine the prevalence of H. pylori infection and NSAID ingestion in a group of patients with GU and determine their roles in bleeding and non-bleeding GU. METHODS AND RESULTS From January 1993 to June 1996, a total of 217 GU patients (150 male, 67 female, median age 61 years, range 26-94) were eligible for the study. Eighty-five per cent were H. pylori-positive and 15% were H. pylori-negative. NSAID usage within 4 weeks prior to endoscopy was present in 30%, more in the H. pylori-negative than H. pylori-positive patients (59% vs. 25% P = 0.0002). Aspirin was most commonly used (43%). One hundred patients bled from GU (69 male, 31 female, mean age 67 years, range 26-94) and 117 did not (81 male, 36 female, mean age 57 years, range 28-86). Univariate logistic regression showed that advanced age (>/= 65 years) and NSAID usage carried an increased risk of bleeding GU (odds ratio 3.4 and 6.8, respectively) while H. pylori infection alone was not associated with additional risk (OR = 0.8). However, when three variables were considered jointly in a multiple logistic regression, the OR associated with H. pylori infection increased to 2.4, suggesting that in the presence of NSAIDs and advanced age, H. pylori also increases the risk of bleeding GU, indicating an interaction between the variables. CONCLUSION NSAID usage and advanced age are risk factors for bleeding GU, whereas H. pylori infection by itself is not. In the presence of NSAIDs and advanced age, an increased risk of bleeding GU with H. pylori is observed, indicating the possibility of an interaction between these factors.
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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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Coorpender SJ, Klyce SD, McDonald MB, Doubrava MW, Kim CK, Tan AL, Srivannaboon S. Corneal topography of small-beam tracking excimer laser photorefractive keratectomy. J Cataract Refract Surg 1999; 25:674-84. [PMID: 10330644 DOI: 10.1016/s0886-3350(99)00015-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
PURPOSE To evaluate the topographic characteristic of photorefractive keratectomy (PRK) for low myopia performed with a small-beam (0.9 mm) tracking excimer laser. SETTING Department of Ophthalmology, LSU Eye Center, Louisiana State University Medical Center School of Medicine in New Orleans, and the Refractive Surgery Center of the South at the Eye, Ear, Nose, & Throat Hospital, New Orleans, Louisiana, USA. METHODS Sixty-seven eyes of 47 patients had PRK with a small-beam tracking laser. Of these, 49 eyes had data permitting evaluation of ablation centration; usable data for topographic analysis were available for 59 eyes preoperatively, 54 eyes at 1 month, 42 eyes at 3 months, and 25 eyes at 6 months, permitting measurement of various topographic parameters, including the cylinder (CYL), average corneal power (ACP), surface regularity index (SRI), surface asymmetry index (SAI), corneal eccentricity index (CEI), and coefficient of variation of corneal power (CVP). RESULTS Preoperatively, all eyes were topographically normal. Postoperatively, no eye exhibited a "central island" by even the least-restrictive definition, and all eyes had best spectacle-corrected visual acuities (BSCVAs) of 20/20 or better at all follow-ups. Mean decentration of the ablations from the pupil centers was 0.42 mm +/- 0.28 (SD) (n = 49). There was no correlation between measured decentration and BSCVA (P = .46). The central cornea was flattened (decreased ACP; P < .001) and made oblate (decreased CEI; P < .001) as expected. There was no increase in SRI or SAI (irregular astigmatism) at 6 months compared with preoperative values (P = .91); however, CYL and CVP (varifocality) increased slightly (P = .04 and .02, respectively). CONCLUSION The absence of significant regular or irregular astigmatism 6 months after PRK with the small-beam laser is an improvement over published results achieved with wide-beam lasers and is consistent with the excellent visual acuity results in this cohort.
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Koh LL, Kon OL, Loh KW, Long YC, Ranford JD, Tan AL, Tjan YY. Complexes of salicylaldehyde acylhydrazones: cytotoxicity, QSAR and crystal structure of the sterically hindered t-butyl dimer. J Inorg Biochem 1998; 72:155-62. [PMID: 10094614 DOI: 10.1016/s0162-0134(98)10075-2] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
A series of acylhydrazones of salicylaldehyde and their transition metal complexes, predominantly copper(II), have been prepared and characterized. The crystal structure of the Cu(II) complex of the sterically hindered t-butyl derivative contains a phenolato bridged dimer with the ligand coordinated as a tridentate moiety. QSAR analyses of the cytotoxicity of the chelators and their Cu(II) complexes reveals that solubility is the dominant factor for activity. Compounds display a maximum with respect to lipophilicity, allowing optimization of the bioactivity for both the ligands and their complexes. Copper complexes are significantly more cytotoxic than the metal-free ligands and complexes of other metals: Cu > Ni > Zn = Mn > Fe = Cr > Cr > Co.
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Mustonen RK, McDonald MB, Srivannaboon S, Tan AL, Doubrava MW, Kim CK. In vivo confocal microscopy of Fuchs' endothelial dystrophy. Cornea 1998; 17:493-503. [PMID: 9756443 DOI: 10.1097/00003226-199809000-00006] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE The purpose of this study is to analyze in vivo confocal microscopic findings of corneas with Fuchs' endothelial dystrophy. METHODS Central corneas of 17 eyes of 11 patients aged 41-86 years were examined using in vivo scanning slit confocal microscopy after being diagnosed with Fuchs' endothelial dystrophy. The cellular structure of the corneas was analyzed morphologically and quantitatively and compared to control results from 22 healthy corneas. RESULTS Bullae were detected in the basal epithelial layer of one eye. Eight of 17 eyes (47%) exhibited an abnormal Bowman's layer: diffuse bright reflection and absence of nerves. Eleven eyes (65%) exhibited abnormal anterior stroma: lacunae and diffuse increased light reflection due to edema. In 12 eyes (71%), lacunae or dark bands 5-20 microm wide against increased background reflection were noted in the posterior stroma. Descemet's membrane was thickened in all eyes. Dark bands were detected in six eyes (35%). Guttae (137-1,231/mm2) 20-40 microm in diameter were found in every endothelial cell layer. The mean endothelial cell count was 1,202 +/- 850 (cells/mm2 +/- SD; range, 0-2,735). There was a positive correlation between endothelial cell counts obtained by specular microscopy and those obtained by confocal microscopy (r = 0.95). CONCLUSION In vivo confocal microscopic findings of Fuchs' endothelial dystrophy are described for the first time in a series of cases. Pathological changes in Fuchs' dystrophy were detected in all corneal layers, more frequently in the posterior layers. Endothelial cell counts obtained with confocal microscopy were statistically similar to those obtained with standard specular microscopy.
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Mustonen RK, McDonald MB, Srivannaboon S, Tan AL, Doubrava MW, Kim CK. Normal human corneal cell populations evaluated by in vivo scanning slit confocal microscopy. Cornea 1998; 17:485-92. [PMID: 9756442 DOI: 10.1097/00003226-199809000-00005] [Citation(s) in RCA: 94] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To analyze cellular populations in healthy human corneas. METHODS The study group consisted of 58 eyes of 45 patients with normal corneas. The age distribution was 45 +/- 17 years (mean +/- SD; range, 20-84). Scanning slit confocal microscopy of the central corneas was performed. The images were analyzed visually for cell morphology, and the densities and areas of cells were measured. RESULTS No statistically significant differences were measured in cell densities or cell areas of any corneal layer between female and male patients (p = 0.22-0.50) nor between right and left eyes (p = 0.16-0.45). The area of superficial epithelial cells was 913 +/- 326 microm2 (mean +/- SD; range, 518-2,112), and the superficial epithelial cell density was 1,213 +/- 370 cells/mm2 (mean +/- SD; range, 473-1,929). The area of basal epithelial cells was 177 +/- 19 microm2 (mean +/- SD; range, 138-242), and the basal epithelial cell density was 5,699 +/- 604 cells/mm2 (mean +/- SD; range, 4,135-7,267). The average apparent keratocyte density was 1,058 +/- 217 cells/mm2 (mean +/- SD; range, 604-1,599) in the anterior stroma, and 771 +/- 135 cells/mm2 (mean +/- SD; range, 493-1,145) in the posterior stroma. The difference in apparent keratocyte densities between the anterior and posterior stroma was statistically significant (p < 0.001). The average endothelial cell area was 334 +/- 51 microm2 (range, 273-553), and the cell density was 3,055 +/- 386 cells/mm2 (mean +/- SD; range, 1,809-3,668). The endothelial cell density had a negative, statistically significant correlation with age (r = -0.68, p < 0.001). The densities of the other corneal cell layers did not have a statistically significant correlation with age. CONCLUSION In vivo scanning slit confocal microscopy is a useful tool for studying corneal cell populations. Central corneal cell densities were found to decrease significantly with age only in the endothelium. For the first time in human corneas using in vivo confocal microscopy, this study statistically confirms a higher apparent number of keratocytes in the anterior stroma than in the posterior stroma.
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Go M, Ngiam T, Tan AL, Kuaha K, Wilairat P. Structure—activity relationships of some indolo[3,2-c]quinolines with antimalarial activity. Eur J Pharm Sci 1998; 6:19-26. [PMID: 16256704 DOI: 10.1016/s0928-0987(97)00064-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/1996] [Accepted: 04/04/1997] [Indexed: 10/17/2022]
Abstract
The synthesis, physicochemical characterization and in vitro antimalarial activity of a series of indolo[3,2-c]quinolines (9a-f) are described. There is only a poor correlation between the activity and hydrophobicity. In contrast, 33% of the observed variation in antimalarial activity can be attributed to the size of the side chain attached to position 9 of the indoloquinoline ring. An increase in the size of this dibasic side chain generally results in a reduction in activity, suggesting that it is accommodated in a site/cavity of limited size on the receptor. More significantly, the charge on the distal nitrogen (N3) on the side chain, located 10-11 A from the quinoline N, could account for 75% of the observed variation. Since a large charge on N3 is associated with improved antimalarial activity, it is suggested that N3 is protonated and functions as a H bond donor in the drug-receptor interaction.
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Tan AL, Jones RW, White JE. Progression of vulvar intraepithelial neoplasia III to invasive carcinoma in a young woman. JOURNAL OF OBSTETRICS AND GYNAECOLOGY (TOKYO, JAPAN) 1995; 21:467-9. [PMID: 8542470 DOI: 10.1111/j.1447-0756.1995.tb01038.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
This case documents the progression of untreated vulvar intraepithelial neoplasia to invasion in a young woman over a four and a half year period. Conflicting views with regards to the natural history of VIN II are discussed.
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Yap EH, Thong TW, Tan AL, Yeo M, Tan HC, Loh H, Teo TP, Thong KT, Singh M, Chan YC. Comparison of Pseudomonas pseudomallei from humans, animals, soil and water by restriction endonuclease analysis. Singapore Med J 1995; 36:60-2. [PMID: 7570138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Pseudomonas pseudomallei isolates from 62 human, 17 animal, 3 soil and 3 water samples were examined by genomic DNA digestion with PstI. Five major (RE I, II, III, IV, V) reproducible restriction patterns were observed, with most (56/62) of the human isolates displaying RE I (30/62), II (5/62), III (15/62), IV (4/62), V (2/62), and the animal (16/17), soil (2/3), water (3/3) isolates showing predominantly RE II profiles. Six human and one soil isolates showed patterns different from those of RE I to V. Restriction endonuclease analysis may be applied in epidemiological studies of melioidosis.
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Ngan CC, Tan AL. Bacteroides fragilis meningitis. Singapore Med J 1994; 35:283-5. [PMID: 7997905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Bacteroides fragilis is an obligate anaerobic bacillus residing in the normal intestinal flora of the colon. Anaerobic bacterial meningitis due to this pathogen is rarely diagnosed and if present, a predisposing source of infection should be actively sought for. Anaerobic cultures of cerebrospinal fluids should be done for patients with meningitis, especially those with concomitant pathologies that predispose to anaerobic infections. Two cases of anaerobic meningitis due to Bacteroides fragilis, one associated with cholesteotoma and the other with nasopharyngeal carcinoma, are reported. Both were successfully treated with metronidazole.
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Ng TM, Fock KM, Ho J, Tan AL, Chia SC, Yap CK, Chew CN, Chee EN. Clotest (rapid urease test) in the diagnosis of Helicobacter pylori infection. Singapore Med J 1992; 33:568-9. [PMID: 1488662] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Over a period of 3 months, 85 patients who underwent gastroscopy had antral biopsy taken for Clotest, histology and/or culture for Helicobacter pylori (HP). The sensitivity and specificity of Clotest were found to be 77% and 96% respectively with negative predictive value of 63% and positive predictive value of 98%. Ninety-two percent of the positive Clotests were positive within 20 minutes, thus giving rapid result. Therefore, Clotest is a rapid, sensitive and highly specific test for HP infection. A high correlation between HP infection and chronic gastritis was noted and the prevalence of HP infection in patients with duodenal ulcer (90%) was higher than that of gastric ulcer (64%) or non-ulcer group (65%).
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Chia KS, Tan AL, Chia SE, Ong CN, Jeyaratnam J. Renal tubular function of cadmium exposed workers. ANNALS OF THE ACADEMY OF MEDICINE, SINGAPORE 1992; 21:756-9. [PMID: 1284195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The kidney is considered the critical organ following long term occupational or environmental exposure to cadmium. Tubular dysfunction in the form of low molecular weight proteinuria is the earliest manifestation of cadmium nephrotoxicity. The current acceptable critical concentration of cadmium in the urine is 10 ug Cd/g creatinine. The aim of this paper is to identify the presence of tubular dysfunction among workers with less than 10 ug Cd/g creatinine. The exposed group of 92 workers were from a nickel-cadmium battery factory. The control group of 122 workers were factory and sedentary office workers with no known history of exposure to nephrotoxic agents. The urinary excretion of N-acetyl-D-glucosaminidase (NAG), beta-2-microglobulin (beta 2m) and alpha-1-microglobulins (alpha 1m) were measured from morning spot urine samples. The age, sex and race adjusted NAG and alpha 1m showed increasing trend with rising urinary cadmium levels. Levels were significantly raised when the urinary cadmium was above 5 ug Cd/g creatinine. A similar trend was seen with increasing length of exposure. Renal tubular dysfunction is present among cadmium exposed workers with levels below the current critical concentration.
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