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Biomedical subjects

E S Tan

Publications and source records attributed to E S Tan.

At least 19 recordsLinked to original sources
PubMed2007

Non-ketotic hyperglycinemia is usually not detectable by tandem mass spectrometry newborn screening.

Diagnosis of Non-Ketotic Hyperglycinemia by MSMS newborn screening might benefit patients with post-neonatal presentation. We screened 733,527 babies over eight years, and nine babies were subsequently diagnosed with NKHG. Two had newborn glycine levels above our cut-off and presented within 72 h. The remaining patients could not have been diagnosed by newborn screening without an unacceptably high recall rate. We conclude that babies with NKHG are not usually identifiable by current newborn screening strategies.

Glycine↗
PubMed2005

SMN1 deletions among singaporean patients with spinal muscular atrophy.

INTRODUCTION: Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder characterised by degeneration of spinal cord anterior horn cells, leading to muscular atrophy. It is the second most frequent autosomal recessive disease among Caucasian populations with a prevalence of between 1 in 6000 and 1 in 10,000 live births, and a carrier frequency of about 1 in 50. The International SMA Consortium classification defines several types of SMA depending on the age of onset and clinical severity. In the past, the diagnosis of SMA was confirmed by muscle biopsy and, sometimes, electromyography. In 1990, SMA was linked to the 5q13 region of chromosome 5. In 1995, it was found that >95% of patients with SMA have homozygous deletions of exons 7 and 8 of the survival motor neurone 1 (SMN1) gene, one of the candidate genes identified within 5q13. The purpose of our study was to determine the frequency of SMN1 deletions in patients with known SMA and the impact of this on the diagnosis of SMA. MATERIALS AND METHODS: Molecular analysis was performed on stored DNA and case notes were reviewed retrospectively. RESULTS: Twenty-two (91.7%) out of 24 patients with all types of SMA were homozygously deleted for exons 7 and/or 8 of SMN1. We also report our experience with prenatal diagnosis of SMA. CONCLUSIONS: Molecular studies can replace conventional investigations for SMA and have made the option of prenatal diagnosis possible for couples at risk.

Adult↗
PubMed2004

Radiofrequency ablation of atrial fibrillation.

UNLABELLED: Twenty-five patients (16 males, mean age 46 years) underwent radiofrequency ablation because of either paroxysmal (13 patients) or persistent atrial fibrillation (12 patients). Ablation aimed at earliest activation of spontaneous and catheter-induced repetitive ectopy in left and right atria and appendages, and pulmonary veins. Catheter-induced repetitive ectopy was defined as acute onset of a burst of rapid atrial premature beats on touching the wall, sustained irritability while at the spot and acute termination of rapid activity upon release of the catheter. Post-ablation patients received antiarrhythmic drugs to prevent tachycardias, thereby allowing reversal of atrial remodeling. RESULTS: Lone atrial fibrillation was present in 19 patients, 4 patients had hypertension and 2 patients coronary artery disease with preserved left ventricular function. The median duration of the history of atrial fibrillation was 4 years (range 1-14 years) and the median number of antiarrhythmic drug failures 5 (range 1-6). Ablation was successful, i.e. no recurrences of atrial fibrillation with or without antiarrhythmic drugs in eight patients (32%) during a median follow-up of 28 months (range 18-52). The median number of foci was 3 (range 2-6) and 2 (range 1-7) in the successfully and unsuccessfully treated patients, respectively. Minor complications occurred in three patients. CONCLUSIONS: Radiofrequency ablation of atrial fibrillation aiming at spontaneous and catheter-induced repetitive ectopy is a safe procedure. However, it is only successful in one third of the patients. Further investigations are warranted to identify the ideal patient, as well as to develop better ablation strategies.

Anti-Arrhythmia Agents↗
PubMed2002

Safety evaluation of routine intracoronary acetylcholine infusion in patients undergoing a first diagnostic coronary angiogram.

BACKGROUND: Recent findings imply prognostic significance of intracoronary acetylcholine infusion for endothelial function testing. We evaluated whether routine use of this test in coronary angiography patients is safe. METHODS: Patients undergoing a first diagnostic coronary angiography were selected to receive intracoronary acetylcholine for endothelial function evaluation. The relation between adverse reactions during infusion and risk factors was analyzed with a logistic regression model. Included in the multiple logistic regression model were the variables with a univariate P value < 0.20. RESULTS: Adverse reactions occurred in 16% (49/299) of the patients. This included two life-threatening events caused by occlusive spasm and flow limitation in the left coronary artery. Other adverse events were chest pain (n = 38), AV block or sinus bradycardia (n = 10), dyspnea (n = 3). Adverse reactions were more likely to occur in patients younger than 60 years of age (relative risk, 5.6 [2.2-14.3]). CONCLUSION: Intracoronary acetylcholine infusion is safe, but may lead to serious adverse reactions. Care should be taken especially in patients younger than 60 years of age. Routine use of acetylcholine infusion can thus only be justified if it has important prognostic significance. This has to be proven further in large prospective studies.

Acetylcholine↗
PubMed2001

Mental health in Asia: social improvements and challenges.

Remarkable improvements in economic conditions and a considerable upgrade in the quality of life have been observed in many parts of Asia during the past several decades. At the same time, many mental health challenges face the people of Asia. Various social mental health indexes are reviewed here, with available data from China, Japan, Korea, Singapore, Malaysia, and other Asian societies. The data are compared with data from the United States, Australia in the Pacific Rim, and some other Western countries to examine patterns of similarity or difference between East and West in the process of modernization. Common trends in mental health issues associated with rapid sociocultural change observed in different Asian societies are discussed, as well as the relative shortage of mental health personnel available in many Asian societies. It is emphasized that, in addition to expanding psychiatric services, there is an even more urgent need to promote mental health knowledge and concern through education in the general population. Mental health needs to be cultivated and maintained by social forces and cultural strengths. It is stressed that there is a challenge for Asian people to advance mental health beyond economic development in the 21st century.

Asia↗
PubMed2000

Durability of aortic valve preservation and root reconstruction in acute type A aortic dissection.

BACKGROUND: The aim of this study was to determine the durability of aortic valve preservation and root reconstruction in type A aortic dissection with involvement of the aortic root. METHODS: From November 1976 to February 1999, 246 patients underwent surgical treatment for acute type A aortic dissection at our institution. In 121 patients (49%), all with acute type A dissection and aortic root involvement, the aortic valve was preserved and one or more of the sinuses of Valsalva were reconstructed. The mean age of this group was 59 +/- 11 years and 70 (58%) were men. Thirty patients (25%) were operated in cardiogenic shock. Criteria for aortic root reconstruction were technical feasibility and surgeon preference. Techniques used for reconstruction were valve resuspension in all patients and additional reinforcement of the aortic root with Teflon (L.R. Bard, Tempe, AZ) felt (n = 21), gelatin-resorcinol-formaldehyde-glue (GRF-glue, Fii, Saint-Just-Malmont, France) (n = 103), or fibrinous glue (Tissu-col, Immuno AG, Vienna, Austria) (n = 5). Mean follow-up was 43.5 +/- 46 months. RESULTS: The operative mortality was 21.5% (n = 26). Actuarial survival was 72% +/- 4%, 64% +/- 5%, and 53% +/- 6% at 1, 5, and 10 years, respectively. Median aortic regurgitation in patients with retained native aortic valve at follow-up was 1+. All root reoperations included aortic valve replacement (n = 12). Freedom from aortic root reoperation was 95% +/- 2% at 1 year, 89% +/- 4% at 5 years, and 69% +/- 9% at 10 years. The incidence of aortic root reoperation was 23%, 11%, and 40%, respectively, when Teflon felt, GRF-glue, and fibrinous glue were used for root reconstruction. Multivariate Cox proportional hazard analysis revealed the use of fibrinous glue (RR = 8.7; p = 0.03) as well as the presence of an aortic valve annulus more than 27 mm (RR = 4.2; p = 0.04) as independent risk factors for aortic root reoperation. CONCLUSIONS: Aortic valve preservation in acute type A dissection provides relatively durable results. The use of fibrinous glue for root reconstruction seems to compromise the long-term durability of the repair compared with Teflon felt and GRF-glue. A dilated aortic annulus requires a more extensive root procedure.

Actuarial Analysis↗
PubMed1999

Worse clinical outcome but similar graft patency in women versus men one year after coronary artery bypass graft surgery owing to an excess of exposed risk factors in women. CABADAS. Research Group of the Interuniversity Cardiology Institute of The Netherlands. Coronary Artery Bypass graft occlusion by Aspirin, Dipyridamole and Acenocoumarol/phenoprocoumon Study.

OBJECTIVES: This retrospective study sought to assess differences in graft patency and clinical outcome between women and men after coronary artery bypass graft surgery (CABG). BACKGROUND: A less favorable clinical outcome has been reported in women as compared with men. Its relation to graft patency has not been studied. METHODS: We analyzed one-year follow-up data of 912 patients (120 women) who entered a randomized clinical drug trial. All patients received vein grafts; in 494 patients (56 women) internal mammary artery (IMA) grafts were also used. Graft patency was assessed by coronary angiography at one year. Primary clinical end points were myocardial infarction, revascularization procedures and death; secondary clinical end points included recurrent angina, heart failure and arrhythmias. RESULTS: Occlusion rates of vein grafts were 16.7% in women and 12.4% in men (odds ratio [OR] 1.62, 95% confidence interval [CI] 0.88 to 3.00, p = 0.12); occlusion rates of IMA grafts were 3.4% and 5.7% in women and men, respectively (OR 0.56, 95% CI 0.08 to 3.96, p = 0.56). Primary clinical end points were observed in 16.7% of women and 9.2% of men (OR 1.97, 95% CI 1.10 to 3.34, p = 0.022), and any clinical end point in 41.7% of women and 25.8% of men (OR 2.06, 95% CI 1.39 to 3.04, p = 0.0004). Myocardial infarction (15% vs. 7.6%, OR 2.15, 95% CI 1.24 to 3.75, p = 0.013) and recurrent angina (26.7% vs. 15.4%, OR 2.00, 95% CI 1.28 to 3.11, p = 0.004) occurred most frequently. Multivariate regression analysis did not identify gender as an independent risk factor for graft occlusion or the clinical end points. Graft occlusion was an independent predictor of the composite primary clinical end point (OR 2.75, 95% CI 1.59 to 4.75, p = 0.0003) and each of the secondary clinical end points. The observed differences were due to an imbalance of risk factors at baseline and to surgical and graft characteristics. CONCLUSIONS: One-year occlusion rates of vein and IMA grafts were comparable in women and men. Clinical outcome was related to graft patency and was less favorable in women owing to their uneven distribution of risk factors among both groups.

Aged↗
PubMed1997

Aspirin therapy in nonarteritic anterior ischemic optic neuropathy.

PURPOSE: To determine the benefit of aspirin in reducing the risk of nonarteritic anterior ischemic optic neuropathy in the fellow eye following its occurrence in the first eye. METHODS: A retrospective cohort study was conducted on 431 patients, 153 of whom were and 278 of whom were not prescribed aspirin following the development of unilateral nonarteritic anterior ischemic optic neuropathy. RESULTS: The 2-year cumulative probability of nonarteritic anterior ischemic optic neuropathy in the fellow eye was 7% in the aspirin group and 15% in the no-aspirin group, and 5-year cumulative probabilities were 17% and 20%, respectively. Compared with the no-aspirin group, the rate ratio for nonarteritic anterior ischemic optic neuropathy in the fellow eye in the aspirin-user group was 0.43 (95% confidence interval, 0.19 to 0.92) over the first 2 years and 0.68 (95% confidence interval, 0.36 to 1.26) over the 5-year period. The overall calculated 5-year risk was 19%; however, if none of the patients with incomplete follow-up developed nonarteritic anterior ischemic optic neuropathy in the fellow eye, then the 5-year risk would be about 12%. CONCLUSIONS: The 5-year risk of nonarteritic anterior ischemic optic neuropathy occurring in the second eye is far lower than that reported by previous studies. Our results suggest a possible short-term but little or no long-term benefit to aspirin in reducing the risk of nonarteritic anterior ischemic optic neuropathy in the fellow eye. However, this finding must be viewed with caution because this study was not conducted prospectively with a controlled protocol.

Aspirin↗
PubMed1996

Comparison between positron emission tomography myocardial perfusion imaging and intracoronary Doppler flow velocity measurements at rest and during cold pressor testing in angiographically normal coronary arteries in patients with one-vessel coronary artery disease.

With use of invasive methods, coronary endothelial function is generally studied by examining the response of epicardial coronary arteries to intracoronary administered acetylcholine or to cold pressor testing. Because invasive methods have substantial inherent limitations, studies should attempt to evaluate coronary endothelial function noninvasively. This study examines a noninvasive technique for endothelium-related coronary stress testing. In myocardial regions supplied by nonstenotic coronary arteries, we compared positron emission tomography (PET) myocardial perfusion imaging with intracoronary Doppler flow velocity measurements during endothelium-related stress testing. PET perfusion was examined at rest and during cold pressor testing in 10 patients with 1-vessel coronary artery disease. In nonstenotic coronary arteries, flow velocity measurements were obtained at rest, during cold pressor testing, and during intracoronary administered acetylcholine. Perfusion and flow velocity responses and stress/rest ratios were compared between the techniques during the various circumstances. Positive correlations were found between: (1) cold pressor Doppler flow velocity responses and acetylcholine Doppler flow velocity responses (r = 0.84, SEE = 0.19, p = 0.003); (2) cold pressor PET perfusion responses and cold pressor Doppler flow velocity responses (r = 0.70, SEE = 0.17, p = 0.02); and (3) cold pressor PET perfusion responses and acetylcholine Doppler flow velocity responses (r = 0.62, SEE = 0.19, p = 0.05). These results suggest that in angiographically normal coronary arteries, both the flow velocity and the perfusion responses during cold pressor testing may be related to the response to acetylcholine.

Acetylcholine↗
PubMed1996

Microchip implants on the anterior sacral roots in patients with spinal trauma: does it improve bowel function?

PURPOSE: This study evaluated the effect of anterior sacral roots stimulator implants on bowel function of patients with spinal cord trauma. METHOD: Eight patients with spinal cord injury and constipation had anterior sacral roots stimulator implants inserted for concomitant bladder dysfunction. Questionnaires on bowel function and anorectal manometry tests were given before and after insertion of the implants. RESULTS: Six patients achieved improvement in bowel function. Four of these patients could defecate spontaneously following stimulation. Two patients had no improvement in bowel function. Anorectal manometry studies showed a negative rectoanal pressure difference at the time of stimulation. All patients were unable to defecate during stimulation. Positive rectoanal pressure difference was recorded in the six patients who had improved bowel function. This may be attributable to the slower relaxation of the smooth rectal muscle compared with the easily fatigable striated external anal sphincter. CONCLUSION: Anterior sacral roots stimulator implants can improve bowel function in patients with spinal cord trauma.

Adult↗
PubMed1996

Comparison of myocardial uptake of fluorine-18-fluorodeoxyglucose imaged with PET and SPECT in dyssynergic myocardium.

UNLABELLED: PET with 18F-fluorodeoxyglucose (FDG) can detect viable myocardium and predict functional recovery after revascularization. The use of PET for clinical routine, however, is limited. Recently, imaging FDG with SPECT was proposed. The aim of this study was to compare the diagnostic value of FDG-PET and FDG-SPECT in the detection of viable myocardium in segments with abnormal wall motion. METHODS: Twenty patients with previous myocardial infarction were studied. All underwent FDG-PET and FDG-SPECT during hyperinsulinemic glucose clamping. Regional perfusion was assessed with 13N-ammonia PET and early resting 201TI- SPECT. Regional wall motion was assessed with two-dimensional echocardiography. The agreement between FDG/13N-ammonia PET and FDG/201TISPECT to detect viability in dyssynergic myocardium was 76%. On a patient basis, PET and SPECT yielded comparable results in 17 of 20 patients. In a subgroup of patients with LVEF < or = 35% (n = 12), all PET and SPECT viability data were identical. CONCLUSION: This study shows a good correlation between the detection of viability in dyssynergic myocardium with FDG/13N-ammonia PET and FDG/201TI SPECT, both on a segmental and patient basis.

Ammonia↗
PubMed1996

The neurogenic bladder in spinal cord injury--pattern and management.

This study describes the various types of neurogenic bladder in spinal cord injury in relation to the level of lesion, defines the aims of bladder management, and discusses the importance of highly individualised management strategies and long-term follow-up. Urodynamic studies were done on 47 new patients with traumatic spinal cord injury when they had return of reflexic bladder activity. This study was conducted over a one-year period. Fifty-five per cent (n = 26) sustained cervical injuries (38.5% complete, 61.5% incomplete), 12.8% (n = 6) had thoracic injuries, 29.8% (n = 14) had lumbar injuries, and 2.1% (n = 1) had sacral injury. The urodynamic patterns according to injury level are shown in Table I. In patients with complete cervical injuries, 80% had detrusor sphincter dyssynergia (DSD), and areflexia was seen in 20% (n = 2). Of those with incomplete cervical injury, 7 (43.8%) had DSD, 5 (31.3%) had detrusor hyperrflexia without DSD, and 2 (12.5%) had areflexia or hyporeflexia. Normal urodynamic studies were only found in patients with incomplete cervical injury (n = 2). Of the 6 patients with thoracic injury, 4 (66.6%) had detrusor areflexia and 2 had DSD. The 2 patients with DSD had injury levels at T4/T6 and T5 respectively. Eleven (78.6%) patients with lumbar injury had detrusor areflexia, one (7.1%) had detrusor hyperreflexia (without DSD), and 2 (14.3%) had a normal urodynamic study. The various patterns of bladder management are shown in Table II. In total, there were 17 patients with DSD. Of these, 9 (52.9%) elected for intermittent catheterisation together with pharmacological therapy, 5 (29.4%) passed urine via spontaneous voiding/tapping, one (5.9%) had an in-dwelling catheter by virtue of his lack of manual dexterity and no care-giver, and 2 (11.8%) patients opted for sacral anterior root stimulator (SARS) or the Brindley device. Of the 6 patients with detrusor hyperreflexia, 4 (66.7%) passed urine spontaneously and 2 (33.3%) patients choose intermittent catheterisation together with pharmacologic therapy. There were 20 patients with detrusor areflexia/hyporeflexia; 15 (75%) were on clean intermittent catheterisation, 4 (20%) voided via straining and 1 (5%) had a suprapubic catheter inserted. The re-discovery of intermittent self-catheterisation, improved medical care, bladder training and surgical advances have enabled the goals of bladder management to be realised; namely safe bladder pressures, low residual urine volume and the attainment of continence.

Adolescent↗
PubMed1995

Exercise systolic arterial blood pressure in middle-aged women with normal and elevated arterial blood pressure.

Considerable interindividual variation in the response of blood pressure to exercise has been found. Factors independently contributing to this variation are insufficiently evaluated. This is especially true for women and older age groups. Reference values of progressive maximal exercise testing in middle-aged, active subjects, especially in women, are scarce. In this study, the response of systolic arterial blood pressure during a progressive maximal cycle ergometer test was investigated in 871 physically active female subjects aged 40 years or older with normal, borderline elevated and elevated blood pressure. The influence of 14 different subject characteristics on this response was studied: 63% of variation in exercise systolic blood pressure (eSBP) could be explained by work load, pre-eSBP, age and exercise heart rate. No difference in eSBP with increasing work load was found between the three groups. Subjects with higher exercise heart rates had higher systolic blood pressures at the same work load compared to subjects with lower exercise heart rates. Maximal working capacity (Wmax) was significantly lower in the elevated blood pressure group although maximal heart rate and lactate were similar. Wmax was age-dependent. Other subject variables were not significantly associated with eSBP. Values of eSBP for reference purposes are presented.

Adult↗
PubMed1995

Paroxysmal hypertension in a C4 spinal cord injury--a case report.

Hypertension in a patient with acute spinal cord injury is commonly caused by autonomic dysreflexia, which is a syndrome of paroxysmal hypertension associated with headaches, relative bradycardia and vasomotor instability secondary to sympathetic overactivity. Life-threatening complications such as seizures and intracerebral haemorrhage are largely preventable. We report both acute and chronic forms of autonomic dysreflexia due to underlying urinary and faecal impaction in a 33-year-old female with traumatic C4 quadriplegia. She was successfully managed with a combination of physical and pharmacological measures including calcium channel and sympathetic blockers.

Adult↗
PubMed1995

Functional outcome in young strokes.

Fifty-seven young stroke patients (aged 45 years and below) admitted to a rehabilitation centre were assessed for underlying risk factor/aetiology and functional outcome after rehabilitation. The mean age was 37.2 +/- 6.3 years and the mean length of stay in the rehabilitation ward 38.3 +/- 19.9 days. There were 37 (64.9%) haemorrhagic and 20 (35.1%) ischaemic strokes. Hypertension was the single most important risk factor accounting for 49.1% of all strokes. Vascular abnormalities (arteriovenous malformation, mycotic aneurysm, vasculitis and Moya-moya disease) and cardiogenic embolism secondary to rheumatic valvular heart disease were also significant causes. There was significant improvement in functional status--activities of daily living (ADL) and mobility--after rehabilitation, the mean Functional Status score improving from 9.76 +/- 2.2 on admission to 5.07 +/- 1.95 on discharge (P < 0.01). Higher ADL and mobility function and upper and lower limb motor power of grade 3 and above on admission, absence of dysphasia, left hemiplegia, age less than 40 years and rehabilitation stay of less than 28 days were associated with better functional outcome whilst sex, nature and site of stroke, and length of stay in the acute ward had no significant bearing.

Activities of Daily Living↗
PubMed1994

Detrusor hyperreflexia in strokes.

Urodynamic evaluation via water cystometry was undertaken in 27 patients from 12 to 120 days after cerebrovascular accidents. Seven patients had urinary symptoms--five with urge incontinence, one with frequency and one with sensation of incomplete bladder emptying. The remaining 20 were asymptomatic. Cystometry revealed normal bladder function in 15 patients (55.6%), detrusor areflexia in one patient (3.7%) and detrusor hyperreflexia in 11 patients (40.7%). Of the 11 patients with detrusor hyperreflexia, six (54.5%) were asymptomatic and the remaining five (45.5%) had urge incontinence. The former group had a statistically significant higher first sensation and functional cystometric capacity than the latter. Urge incontinence was also found to be an accurate predictor of detrusor hyperreflexia.

Adult↗
PubMed1994

Reflex sympathetic dystrophy in hemiplegia--two case reports and review of the literature.

Reflex sympathetic dystrophy (RSD) can be precipitated by a variety of events. We report two cases of RSD in hemiplegic patients detected within three months of the cerebrovascular accidents. Diagnosis of RSD was based upon clinical and scintigraphic findings. Management included elevation, range of movement of the affected joints and analgesics. With treatment, the pain and swelling subsided, range of motion of joints improved and the patients were able to participate in the rehabilitation programme. A high index of suspicion, early diagnosis and aggressive treatment were found to be essential for the successful treatment of RSD.

Cerebral Hemorrhage↗