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Biomedical subjects

E Lim

Publications and source records attributed to E Lim.

At least 37 records · Page 2Linked to original sources
PubMed2001

Higher plant glycosyltransferases.

SUMMARY: Uridine diphosphate (UDP) glycosyltransferases (UGTs) mediate the transfer of glycosyl residues from activated nucleotide sugars to acceptor molecules (aglycones), thus regulating properties of the acceptors such as their bioactivity, solubility and transport within the cell and throughout the organism. A superfamily of over 100 genes encoding UGTs, each containing a 42 amino acid consensus sequence, has been identified in the model plant Arabidopsis thaliana. A phylogenetic analysis of the conserved amino acids encoded by these Arabidopsis genes reveals the presence of 14 distinct groups of UGTs in this organism. Genes encoding UGTs have also been identified in several other higher plant species. Very little is yet known about the regulation of plant UGT genes or the localization of the enzymes they encode at the cellular and subcellular levels. The substrate specificities of these UGTs are now beginning to be established and will provide a foundation for further analysis of this large enzyme superfamily as well as a platform for future biotechnological applications.

Amino Acid Sequence↗
PubMed2001

Restless legs syndrome in an Asian population: A study in Singapore.

In face-to-face interviews, we examined 157 consecutive individuals aged 55 years and older, selected from the general population in Singapore, and 1,000 consecutive individuals aged 21 years and older, from a primary healthcare center. Based on the IRLSSG criteria, the prevalence of restless leg syndrome (RLS) was 0.6% and 0.1%, respectively.

Adult↗
PubMed2001

Palpable breast cancer which is mammographically invisible.

We have evaluated tumour characteristics, local recurrence rates and prognostic markers in 40 women with symptomatic palpable breast cancer proven by cytology, but in whom routine two-view mammography failed to detect a radiological abnormality. False negative mammograms were identified by cross-referencing all negative mammograms performed at the Royal Victoria Infirmary during the period 1995-1999, with pathological records at the same institution. The average age was 48 years. The majority of the tumours were invasive ductal carcinomas, 35 with an average size of 24 mm. There were 16 Grade II and 15 Grade III tumours. Lymphovascular invasion was seen in 18 on histology and six patients had distant metastases. Of those patients treated by conservation therapy there has been only one local recurrence, with a median follow-up of 18 months. We conclude that mammographically invisible tumours are of common histological type, are frequently high grade and node positive and occur mainly in the younger age group. However, BCT remains a viable option in the treatment of these tumours.

Journal Article↗
PubMed2001

Type III units in the gerbil dorsal cochlear nucleus may be spectral notch detectors.

Broadband sounds originating in the median plane are thought to be localized by neural processing of spectral notches introduced by the filtering action of the pinnae. Previous studies (Nelken, I., and E. D. Young. J. Neurophysiol. 71:2446-2462, 1994: Spirou, G. A., and E. D. Young. ibid. 66: 1750-1768. 1991) suggested that type IV units in decerebrate cat dorsal cochlear nucleus (DCN) are functional detectors of these spectral notches. Intracellular marking studies by Ding et al. (Ding, J., T. E. Benson, and H. F. Voigt. J. Neurophysiol. 82:3434-3457, 1999) have shown that type III units in gerbil arise from the DCN's principal output neurons, which are thought to have type IV unit properties in cat. A relative paucity of type IV units in the decerebrate gerbil (Davis. K. A., J. Ding, T. E. Benson, and H. F. Voigt. J. Neurophysiol. 75: 1411-1431, 1996) has motivated this study of spectral notch sensitivity in the gerbil DCN. Responses to notch noise stimuli were recorded from 15 gerbil type III units to investigate whether these units may function as spectral notch detectors. For narrow notch noise stimuli, all 15 units showed excitatory responses. For progressively wider notches, the discharge rate of 13/15 units became inhibited. As the maximum limits of notch width were approached, 11/15 units showed some degree of recovery from this inhibition. This response pattern in gerbil type III units possesses the salient features of notch noise responses in cat type IV units and implicates type III units in gerbilline spectral notch detection processes.

Acoustic Stimulation↗
PubMed2001

Non-thyphoidal salmonellosis in patients with systemic lupus erythematosus. A study of fifty patients and a review of the literature.

The objective of this study was to characterize the clinical profile of lupus patients with non-typhoidal salmonellosis. A retrospective review of the clinical charts of lupus patients diagnosed with bacteriologically proven non-typhoidal salmonellosis over the last 20 y was undertaken, paying special attention to risk factors, clinical presentation and treatment outcome. Most episodes were bacteraemic without a localizing focus; and some patients were afebrile. They usually occurred in patients prone to opportunistic infections, and at times of increased immunosuppression given for lupus flares (especially nephritis). However, salmonellosis also occurred in some patients presenting with lupus. The C-reactive protein level was found to be significantly higher during the infective episodes compared to episodes of non-infective febrile lupus flare. All isolates were sensitive to the usual first-line antibiotics and eminently treatable with 3 weeks of appropriate antibiotics without recurrence/persistence or significant morbidity/mortality, the exceptions being spinal osteomyelitis and septic arthritis involving deformed joints requiring surgical debridement and prolonged antibiotic therapy for eradication. Mortality occurred in the setting of septic shock from mixed-microbial sepsis and major organ failure from active lupus. There is a high association of non-epidemic, non-typhoidal salmonellosis with SLE, especially in patients with active disease on intensified immunosuppression. The C-reactive protein value may be helpful in distinguishing between fever from a pure lupus flare and one complicated by infection.

Adolescent↗
PubMed2000

The unusual mammographic appearance of breasts augmented by autologous fat injection.

We report the case of a woman presenting to our centre with two breast lumps, 12 months after undergoing breast augmentation with autologous fat injection. Mammography showed a very unusual appearance, with most of the breast parenchyma displaced anteriorly by a large amount of fatty tissue. This was associated with extensive bizarre microcalcification, highlighting the difficulty in mammographic evaluation of this rare type of breast augmentation.

Journal Article↗
PubMed2000

Dynamic helical computed tomography scan accurately detects hemorrhage in patients with pelvic fracture.

BACKGROUND: The purpose of this study was to evaluate the use of dynamic helical computed tomography (CT) scan for screening patients with pelvic fractures and hemorrhage requiring angiographic embolization for control of bleeding. METHODS: Patients admitted to the trauma service with pelvic fractures were identified from the trauma registry. Data retrieval included demographics, hemodynamic instability, Injury Severity Score, blood transfusion requirement, length of stay, and mortality. CT scans obtained during the initial evaluation were reviewed for the presence of contrast extravasation and correlated with angiographic findings. Data are reported as mean +/- SEM, with P<.05 considered significant. RESULTS: Seven thousand seven hundred eighty-one patients were admitted from June 1994 to May 1999. A pelvic fracture was diagnosed in 660 (8.5%). Two hundred ninety (44.0%) dynamic helical CT scans were performed, of which 13 (4.5%) identified contrast extravasation. Nine (69%) were hemodynamically unstable and had pelvic arteriography performed. Arterial bleeding was confirmed in all and controlled by embolization. Patients with contrast extravasation had significantly greater Injury Severity Score, blood transfusion requirement and length of stay. Sensitivity, specificity, and accuracy of CT scan for identifying patients requiring embolization were 90.0%, 98.6%, and 98.3%, respectively. CONCLUSIONS: Early use of dynamic helical CT scanning in the multiply injured patient with a pelvic fracture accurately identifies the need for emergent angiographic embolization.

Abdominal Injuries↗
PubMed2000

Spinocerebellar ataxia in Singapore: predictive features of a positive DNA test?

Significant differences in frequency of the different spinocerebellar ataxia (SCA) subtypes have been described to occur in different populations. A 'blunderbuss' diagnostic DNA testing approach would entail unnecessary healthcare cost. In this study, we determine the prevalence of SCA subtypes and predictive features of a positive DNA test in consecutive clinically diagnosed SCA cases in Singapore. Twenty-one consecutive patients from 14 families were evaluated over a 3-year period. Thirteen patients (61.9%) from 6 families had a positive DNA test. Eleven of these (all ethnic Chinese) had SCA 3 (abnormal CAG size ranged from 61 to 71), and 2 ethnic Malays had SCA 2 (abnormal CAG size of 39). Clinical features which were highly predictive of a positive DNA SCA test in our population included presence of a positive family history, chorea and dystonia, muscle and tongue fasciculations, gaze-evoked nystagmus, and hypertonia. Our study draws attention to the observation that knowledge of relatively specific features of the most common SCA subtype in a local population can greatly enhance the practical accuracy of the choice of which SCA DNA test to order.

Adult↗
PubMed2000

Nipah viral encephalitis or Japanese encephalitis? MR findings in a new zoonotic disease.

BACKGROUND AND PURPOSE: An epidemic of suspected Japanese encephalitis occurred in Malaysia in 1998-1999 among pig farmers. In neighboring Singapore, an outbreak occurred among pig slaughterhouse workers. It was subsequently established that the causative agent in the outbreak was not the Japanese encephalitis virus but a previously unknown Hendra-like paramyxovirus named Nipah virus. METHODS: The brain MR images of eight patients with Nipah virus infection were reviewed. All patients tested negative for acute Japanese encephalitis virus. Seven patients had contrast-enhanced studies and six had diffusion-weighted examinations. RESULTS: All patients had multiple small bilateral foci of T2 prolongation within the subcortical and deep white matter. The periventricular region and corpus callosum were also involved. In addition to white matter disease, five patients had cortical lesions, three had brain stem involvement, and a single thalamic lesion was detected in one patient. All lesions were less than 1 cm in maximum diameter. In five patients, diffusion-weighted images showed increased signal. Four patients had leptomeningeal enhancement and four had enhancement of parenchymal lesions. CONCLUSION: The brain MR findings in patients infected with the newly discovered Nipah paramyxovirus are different from those of patients with Japanese encephalitis. In a zoonotic epidemic, this striking difference in the appearance and distribution of lesions is useful in differentiating these diseases. Diffusion-weighted imaging was advantageous in increasing lesion conspicuity.

Abattoirs↗
PubMed1999

Outbreak of Nipah-virus infection among abattoir workers in Singapore.

BACKGROUND: In March 1999, an outbreak of encephalitis and pneumonia occurred in workers at an abattoir in Singapore. We describe the clinical presentation and the results of investigations in these patients. METHODS: Clinical and laboratory data were collected by systemic review of the case records. Serum and cerebrospinal fluid (CSF) samples were tested for IgM antibodies to Nipah virus with an IgM capture ELISA. Reverse-transcriptase PCR was done on the CSF and tissue samples from one patient who died. FINDINGS: Eleven patients were confirmed to have acute Nipah-virus infection based on raised IgM in serum. Nipah virus was identified by reverse transcriptase PCR in the CSF and tissue of the patient who died. The patients were all men, with a median age of 44 years. The commonest presenting symptoms were fever, headache, and drowsiness. Eight patients presented with signs of encephalitis (decreased level of consciousness or focal neurological signs). Three patients presented with atypical pneumonia, but one later developed hallucinations and had evidence of encephalitis on CSF examination. Abnormal laboratory findings included a low lymphocyte count (nine patients), low platelet count, low serum sodium, and high aspartate aminostransferase concentration (each observed in five patients). The CSF protein was high in eight patients and white-blood-cell count was high in seven. Chest radiography showed mild interstitial shadowing in eight patients. Magnetic resonance imaging (MRI) showed focal areas of increased signal intensity in the cortical white marker in all eight patients who were scanned. The nine patients with encephalitis received empirical treatment with intravenous aciclovir and eight survived. INTERPRETATION: Infection with Nipah virus caused an encephalitis illness with characteristic focal areas of increased intensity seen on MRI. Lung involvement was also common, and the disease may present as an atypical pneumonia.

Abattoirs↗
PubMed1999

Effect of a 915-MHz simulated mobile phone signal on cognitive function in man.

PURPOSE: To examine whether a simulated mobile telephone transmission at 915 MHz has an effect on cognitive function in man. MATERIALS AND METHODS: Thirty-six subjects in two groups were each given two training sessions and then three test sessions in a randomized three-way cross-over design. About 1 W mean power at 915 MHz from a quarter-wave antenna mounted on a physical copy of an analogue phone, as a sine wave, or modulated at 217 Hz with 12.5% duty cycle, or no power, was applied to the left squamous temple region of the subjects while they undertook a series of cognitive function tests lasting approximately 25-30 min. The second group was investigated for sleep, consumption of alcohol and beverages, and any other substances that might affect performance. RESULTS: In both groups, the only test affected was the choice reaction time and this showed as an increase in speed (a decrease in reaction time). There were no changes in word, number or picture recall, or in spatial memory. While an effect of visit-order was evident suggesting a learning effect of repeat tests, the design of the study allowed for this. Additionally, there was no systematic error introduced as a result of consumption of substances or sleep time. CONCLUSIONS: There was evidence of an increase in responsiveness, strongly in the analogue and less in the digital simulation, in choice reaction time. This could be associated with an effect on the angular gyrus that acts as an interface between the visual and speech centres and which lies directly under and on the same side as the antenna. Such an effect could be consistent with mild localized heating, or possibly a non-thermal response, which is nevertheless power-dependent.

Absorption↗
PubMed1998

Proliferation and collagen synthesis of human anterior cruciate ligament cells in vitro: effects of ascorbate-2-phosphate, dexamethasone and oxygen tension.

Clinical and experimental studies demonstrate that injured anterior cruciate ligaments (ACL) do not usually heal and that autografts used to repair the ACL rapidly weaken in the early period and take a long time to regain strength. The aim of this study was to develop an in vitro culture system in which environmental and biochemical factors influencing the proliferation and matrix synthesis of cells derived from human anterior cruciate ligaments can be studied. Primary cultures of human ACL cells were obtained by outgrowth from explants of normal ACL obtained at knee replacement for osteoarthritis in Dulbecco's minimum essential medium (DMEM). The effects of the additives 100 microm L-ascorbic acid-2-phosphate (Asc-2-P) and 10 n m dexamethasone (dex) on proliferation and collagen synthesis were assessed after 4, 8 and 12 days in culture. Ligament cells were grown at 0, 5, 10 and 21%p O(2)in the presence of 100 microm asc-2-P and 10 n m dex. DNA content was assessed using the Hoechst dye method and collagen synthesis by the incorporation of 5 mCi/ml [(3)H]proline after 3, 6 and 12 days in culture. At 21%p O(2), the presence of asc-2-P and dex induced significantly greater (P< 0.01, ANOVA) cell proliferation than with either additives alone. Greatest percentage collagen to total protein synthesis was observed when cells were grown in the presence of asc-2-P only. Least proliferation and percentage collagen to total protein synthesis was seen when both additives were omitted. Greatest cell proliferation was seen when cells were grown in 10%p O(2)and 5%p O(2)was associated with increased collagen synthesis. These results suggest that it is possible to study the effects of environmental and biochemical factors on human ACL healing in vitro. Our data suggest oxygen can influence certain biosynthetic activities of ACL cells. Low oxygen tensions lead to an increase in collagen production by ACL cells. However early responses to injury require extensive cell proliferation which may be activated at higher p O(2). Variation of p O(2)in ligaments during healing may therefore be an important modulator of successful repair.

Anterior Cruciate Ligament↗
PubMed1998

Effect of taurine supplementation on the lipid peroxide formation and the activities of glutathione-related enzymes in the liver and islet of type I and II diabetic model mice.

Effects of taurine supplementation on lipid peroxide formation and the activities of glutathione (GSH) dependent enzymes in diabetic model mice were investigated. Type I diabetes mellitus was induced by injecting alloxan to ICR mice while type II diabetes mellitus was produced by high calorie diet feeding to genetically hyperglycemic KK mice. Taurine was given in drinking water at the level of 5% (w/v) for seven days. The malondialdehyde (MDA) levels of liver and the islets of type I diabetes were significantly increased compared to the control group but the levels were significantly decreased by taurine supplementation. In the type II diabetic model, the concentrations of MDA were not changed by taurine treatment. The activity of hepatic and islet GSH-peroxidase (GPX) was increased in the type I diabetic group, but in type II animals it was decreased. Hepatic GPX activity of both type I and II diabetics was not altered by taurine supplementation but was increased in the islets of the type II animals. No effect on the activity of GSH S-transferase (GST) was observed in both types of diabetes (I and II) following taurine supplementation. These results suggest that taurine supplementation protects type I diabetic mice from lipid peroxide formation.

Animals↗
PubMed1998

Adult-onset Still's disease in an oriental population: manifestations, course and outcome in 16 patients.

This retrospective descriptive study aims to characterise and compare the clinical manifestations, course and outcome of 16 Oriental patients with adult-onset Still's disease diagnosed in the last 4 years with published data based on Western populations and another Oriental (Japanese) series. Like the Japanese, we found a female preponderance, an older age at onset, and fewer patients with abdominal pain, myalgia, sore throat and serositis compared to the Western series. A longer delay in diagnosis occurred in patients lacking either arthritis or rash at presentation. Most patients had mild hyponatraemia and 2 patients had overt syndrome of inappropriate anti-diuretic hormone secretion. All patients showed a dissociation of elevated aldolase with normal to low creatine kinase levels. Over 50% relapsed within a year from diagnosis and needed slow-acting anti-rheumatic drugs as steroid-sparing agents. Two were given intravenous pulse cyclophosphamide therapy for progressive pneumonitis. Outcome was generally good with minimal functional impairment and no mortality.

Adolescent↗