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Biomedical subjects

W S Lim

Publications and source records attributed to W S Lim.

At least 19 recordsLinked to original sources
PubMed2006

Omega 3 fatty acid for the prevention of dementia.

BACKGROUND: Accruing evidence from observational and epidemiological studies suggests an inverse relationship between dietary intake of omega 3 polyunsaturated fatty acid (PUFA) and risk of dementia. Postulated mechanisms that might qualify omega 3 PUFA as an interventional target for the primary prevention of dementia include its anti-atherogenic, anti-inflammatory, anti-oxidant, anti-amyloid and neuroprotective properties. OBJECTIVES: To review the evidence that omega 3 PUFA supplementation prevents cognitive impairment and dementia in cognitively intact elderly persons. SEARCH STRATEGY: The Cochrane Dementia and Cognitive Improvement Group's (CDCIG) Specialized register, MEDLINE, EMBASE,CINAHL PsycINFO, AMED AND CENTRAL and several ongoing trials databases were searched on 5 and 6 October 2005. The CDCIG Register is updated regularly and contains records from all major medical databases and many ongoing trials databases. SELECTION CRITERIA: In order to be selected, trials needed to be randomized, placebo-controlled, doubled blinded, of minimum study duration of 6 months, involved persons aged 60 years and above without pre-existing dementia at study onset, and employed cognitive endpoints. DATA COLLECTION AND ANALYSIS: Reviewers, working independently, were to select, quality assess and extract relevant data where appropriate and possible. In comparing intervention with placebo, the pooled odds ratios or weighted mean differences and standardized mean difference were to be estimated. MAIN RESULTS: There were no randomized trials found in the search that met the selection criteria. Results of two clinical trials are expected in 2008. AUTHORS' CONCLUSIONS: There is a growing body of evidence from biological, observational and epidemiological studies that suggests a protective effect of omega 3 PUFA against dementia. However, until data from randomized trials become available for analysis, there is no good evidence to support the use of dietary or supplemental omega 3 PUFA for the prevention of cognitive impairment or dementia.

Aged↗
PubMed2005

SU proteins from virulent and avirulent EIAV demonstrate distinct biological properties.

Biologic activity of equine infectious anemia virus (EIAV) surface (SU) glycoprotein was assayed in a mouse model. Recombinant SU from virulent EIAV17 (SU17), administered intraperitoneally to mouse pups, induced dose-dependent diarrheal responses similar to those reported for SIV SU (Virology 277 (2000) 250). SU17 caused fluid accumulation without histological lesions in mouse intestinal loops, induced chloride secretory currents in Ussing chambers and increased inositol 1,4,5 triphosphate (IP3) levels in HT29 cells. An SU17 peptide, SU17(299-330), provoked a dose-dependent diarrheal response akin to enterotoxic peptides from SIV. In contrast, SU from an avirulent EIAV strain failed to induce a dose response in mouse pups and produced lower levels of activity than SU17 in Ussing chambers and IP3 assays. These results demonstrate that a mouse pup model is useful to monitor EIAV SU biologic activity, showing clear differences between the activities of SU derived from virulent and avirulent viruses, and may provide a useful screen of EIAV virulence.

Amino Acid Sequence↗
PubMed2004

Comparison of SIVmac239(352-382) and SIVsmmPBj41(360-390) enterotoxic synthetic peptides.

To characterize the active domain of the simian immunodeficiency virus (SIV) surface unit (SU) enterotoxin, peptides corresponding to the V3 loop of SIVmac239 (SIVmac) and SIVsmmPBj41 (SIVpbj) were synthesized and examined for enterotoxic activity, alpha-helical structure, and interaction(s) with model membranes. SIVmac and SIVpbj induced a dose-dependent diarrhea in 6-8-day-old mouse pups similar to full-length SU. The peptides mobilized [Ca(2+)](i) in HT-29 cells with distinct oscillations and elevated inositol triphosphate levels. Circular dichroism analyses showed the peptides were predominantly random coil in buffer, but increased in alpha-helical content when placed in a hydrophobic environment or with cholesterol-containing membrane vesicles that are rich in anionic phospholipids. None of the peptides underwent significant secondary structural changes in the presence of neutral vesicles indicating ionic interactions were important. These data show that the SIV SU enterotoxic domain localizes in part to the V3 loop region and interacts with anionic membrane domains on the host cell surface.

Amino Acid Sequence↗
PubMed2004

Hospital management of adults with severe acute respiratory syndrome (SARS) if SARS re-emerges--updated 10 February 2004.

Severe Acute Respiratory Syndrome (SARS) is a potentially severe and highly infectious disease to which healthcare workers involved in the management of cases are particularly vulnerable. These guidelines briefly summarise optimal and safe practice for clinicians involved in the emergency care of patients with probable or confirmed SARS.

Communicable Diseases, Emerging↗
PubMed2004

Impact of a pharmacist consult clinic on a hospital-based geriatric outpatient clinic in Singapore.

INTRODUCTION: We study the impact of a pharmacist consult clinic on the care of elderly outpatients based on the Health Belief Model that the perceived benefits (improvement in medication knowledge, clinical status and perception) and attached barriers (cost and number of medication and adverse drug reactions) can influence health behaviour (medication compliance). MATERIALS AND METHODS: A randomised controlled study of 136 eligible patients with risk factors for non-compliance, using Zelen's design, was conducted in a hospital-based geriatric outpatient clinic from November 2001 to June 2002. All patients were assessed for outcome variables at baseline and 2 months later. RESULTS: One hundred and twenty-six patients were included in the intention-to-treat analysis. There were 104 pharmacist interventions with a physician acceptance rate of 76%. There was a significant improvement in medication knowledge with regards to indication (P = 0.03) and the composite dose, frequency and indication score (P = 0.06), as well as a decrease in residual adverse drug reactions that persisted at month 2 and cost avoidance of dollars 387.28 over 2 months. There was no significant difference in perception, clinical status or decrease in number of medications. The intervention group showed an improvement in adjusted compliance (odds ration [OR] = 2.52; 90% confidence interval [CI], 1.09 to 5.83) based on the ordered logistic regression model. Perception of severity of illness at baseline (OR = 1.30; 90% CI, 1.04 to 1.62), number of medication remembering methods (OR = 1.87; 90% CI, 1.08 to 3.25) and the use of routine habits (OR = 4.48; 90% CI, 1.51 to 13.28) and medication aids (OR = 3.68; 90% CI, 1.04 to 13.06) significantly affected compliance. CONCLUSION: The addition of a pharmacist consult clinic to the management of selected geriatric outpatients can improve compliance, with the attendant benefits of improving medication knowledge, cost avoidance and reducing residual adverse drug reactions.

Aged↗
PubMed2003

Community-acquired Legionnaires' disease in Nottingham--too many cases?

The aim of this study was to compare the incidence of community-acquired Legionnaires' Disease in Nottingham with England and Wales and to explore reasons for any difference observed. Based on data from the National Surveillance Scheme for Legionnaires' Disease (1980-1999), the rate of infection in England and Wales was 1.3 per million/year compared with 6.6 per million/ year in Nottingham. Domestic water samples were obtained from 41 (95%) of 43 Nottingham cases between 1997 and 2000. In 16 (39%) cases, Legionella sp. were cultured in significant quantities. Proximity to a cooling tower was examined using a 1:4 case-controlled analysis. No significant difference in the mean distance between place of residence to the nearest cooling tower was noted (cases 2.7 km vs. controls 2.3 km; P = 0.5). These data suggest that Nottingham does have a higher rate of legionella infection compared to national figures and that home water systems are a source.

Adolescent↗
PubMed2003

Defining community acquired pneumonia severity on presentation to hospital: an international derivation and validation study.

BACKGROUND: In the assessment of severity in community acquired pneumonia (CAP), the modified British Thoracic Society (mBTS) rule identifies patients with severe pneumonia but not patients who might be suitable for home management. A multicentre study was conducted to derive and validate a practical severity assessment model for stratifying adults hospitalised with CAP into different management groups. METHODS: Data from three prospective studies of CAP conducted in the UK, New Zealand, and the Netherlands were combined. A derivation cohort comprising 80% of the data was used to develop the model. Prognostic variables were identified using multiple logistic regression with 30 day mortality as the outcome measure. The final model was tested against the validation cohort. RESULTS: 1068 patients were studied (mean age 64 years, 51.5% male, 30 day mortality 9%). Age >/=65 years (OR 3.5, 95% CI 1.6 to 8.0) and albumin <30 g/dl (OR 4.7, 95% CI 2.5 to 8.7) were independently associated with mortality over and above the mBTS rule (OR 5.2, 95% CI 2.7 to 10). A six point score, one point for each of Confusion, Urea >7 mmol/l, Respiratory rate >/=30/min, low systolic(<90 mm Hg) or diastolic (</=60 mm Hg) Blood pressure), age >/=65 years (CURB-65 score) based on information available at initial hospital assessment, enabled patients to be stratified according to increasing risk of mortality: score 0, 0.7%; score 1, 3.2%; score 2, 3%; score 3, 17%; score 4, 41.5% and score 5, 57%. The validation cohort confirmed a similar pattern. CONCLUSIONS: A simple six point score based on confusion, urea, respiratory rate, blood pressure, and age can be used to stratify patients with CAP into different management groups.

Adult↗
PubMed2002

Respiratory rate measurement in adults--how reliable is it?

Measurement of respiratory rate (RR) is essential in the evaluation of respiratory disorders. However, the variability in RR measurement in adults has never been adequately assessed. Respiratory rate was measured twice in 245 patients; the two measurements were performed by the same observer in 137 patients, by different observers in 58 patients and simultaneously by different observers in 50 patients. The mean (SD) difference between the first and second measurements was 0.03 (3); 95% limits of agreement-4.86-4.94 breaths min(-1), -5.7-5.7 breaths min(-1), and -4.2 to 4.4 breaths min(-1) for the same observer, different observer and simultaneous observer groups, respectively. The difference in RR measurements did not vary with RR. In conclusions on average, there is very good agreement between observers in RR measurement. Inter-observer variability may account for a difference of up to 6 breaths min(-1). This is relevant when applying clinical prediction rules based on threshold RR values.

Adolescent↗
PubMed2001

Study of community acquired pneumonia aetiology (SCAPA) in adults admitted to hospital: implications for management guidelines.

BACKGROUND: Since the last British study of the microbial aetiology of community acquired pneumonia (CAP) about 20 years ago, new organisms have been identified (for example, Chlamydia pneumoniae), new antibiotics introduced, and fresh advances made in microbiological techniques. Pathogens implicated in CAP in adults admitted to hospital in the UK using modern and traditional microbiological investigations are described. METHODS: Adults aged 16 years and over admitted to a teaching hospital with CAP over a 12 month period from 4 October 1998 were prospectively studied. Samples of blood, sputum, and urine were collected for microbiological testing by standard culture techniques and new serological and urine antigen detection methods. RESULTS: Of 309 patients admitted with CAP, 267 fulfilled the study criteria; 135 (50.6%) were men and the mean (SD) age was 65.4 (19.6) years. Aetiological agents were identified from 199 (75%) patients (one pathogen in 124 (46%), two in 53 (20%), and three or more in 22 (8%)): Streptococcus pneumoniae 129 (48%), influenza A virus 50 (19%), Chlamydia pneumoniae 35 (13%), Haemophilus influenzae 20 (7%), Mycoplasma pneumoniae 9 (3%), Legionella pneumophilia 9 (3%), other Chlamydia spp 7 (2%), Moraxella catarrhalis 5 (2%), Coxiella burnetii 2 (0.7%), others 8 (3%). Atypical pathogens were less common in patients aged 75 years and over than in younger patients (16% v 27%; OR 0.5, 95% CI 0.3 to 0.9). The 30 day mortality was 14.9%. Mortality risk could be stratified by the presence of four "core" adverse features. Three of 60 patients (5%) infected with an atypical pathogen died. CONCLUSION: S pneumoniae remains the most important pathogen to cover by initial antibiotic therapy in adults of all ages admitted to hospital with CAP. Atypical pathogens are more common in younger patients. They should also be covered in all patients with severe pneumonia and younger patients with non-severe infection.

Adolescent↗
PubMed2001

A prospective comparison of nursing home acquired pneumonia with community acquired pneumonia.

Nursing home acquired pneumonia (NHAP) is thought to be clinically distinct from community acquired pneumonia (CAP). This observation, based on studies conducted mainly in North America, may not be relevant in countries with a different healthcare system. The authors describe an 18-month prospective cohort study of 437 patients admitted to hospital with CAP, 40 (9%) of whom came from nursing homes. Detailed microbiological tests were performed in a subset of patients over 12 months. Patients with NHAP were less likely to have a productive cough (odds ratio (OR) 0.4, p=0.02) or pleuritic pain (OR 0.1, p=0.03), but they were more likely to be confused (OR 2.6, p<0.001). They had poorer functional status (p<0.001) and more severe disease (p=0.03). Mortality was higher compared to CAP (53% versus 13%), but this was mainly explained by prior functional status (OR 0.5, after adjustment for functional status). Pathogens were identified in 68% of 22 NHAP and 80% of 44 matched CAP patients. Streptococcus pneumoniae was the most common (55% NHAP, 43% CAP). Atypical pathogens, enteric Gram negative bacilli and Staphylococcus aureus were uncommon. In conclusion, differences in functional status accounted for the increased mortality in nursing home acquired pneumonia compared to community acquired pneumonia. The pathogens implicated were similar. No grounds for a difference in choice of empirical antibiotics were apparent.

Aged↗
PubMed2001

Defining prognostic factors in the elderly with community acquired pneumonia: a case controlled study of patients aged > or = 75 yrs.

Severity assessment in the elderly with community acquired pneumonia (CAP) may be different compared with younger patients. In particular, age per se may not be of prognostic significance in older patients. A case-control study in 158 patients aged > or = 75 yrs with CAP was conducted to determine the factors associated with in-hospital mortality. Cases were drawn from all patients aged > or = 75 yrs with CAP who died in 1997 in five hospitals in the mid-Trent region of the UK (Nottingham City Hospital, University Hospital Nottingham, Derby Royal Infirmary, Derby City General Hospital and Kings Hill Hospital). Controls were randomly selected from survivors also aged > or = 75 yrs. Factors associated with mortality were identified following a review of the medical casenotes and the contribution of these factors to mortality was determined using multivariate analysis. Absence of fever, tachycardia and chest radiograph features of bilateral involvement or an effusion were independently associated with mortality on multivariate analysis. The British Thoracic Society (BTS) severity rule was 50% sensitive and 64% specific in predicting death while the modified BTS rule displayed 67% sensitivity and 58% specificity. Age was not significantly associated with mortality in this group of patients aged > or = 75 yrs. Similarly, the clinical features employed in the British Thoracic Society rule, namely respiratory rate, diastolic blood pressure and blood urea, were not of prognostic significance and the rule itself performed poorly. The modified British Thoracic Society rule performed better.

Aged↗
PubMed2000

A novel method for collecting and detecting amoxycillin in urine: a tool for testing antibiotic compliance in the community.

Assessing compliance to prescribed antibiotics in community studies of respiratory tract infections is difficult. We describe a simple method for collecting and detecting amoxycillin in urine using urine dip-sticks in conjunction with a bioassay. Urine was collected at timed intervals from eight healthy volunteers following oral amoxycillin administration. Dip-sticks inoculated with urine collected 1 and 8 h after antibiotic resulted in mean zones of inhibition of 1.75 and 1.37 cm, respectively. Amoxycillin activity remained demonstrable 14 days after inoculation of dip-sticks with urine. Dip-sticks inoculated with urine from control subjects who had not taken amoxycillin did not cause inhibition.

Amoxicillin↗
PubMed2000

Severity prediction rules in community acquired pneumonia: a validation study.

BACKGROUND: The British Thoracic Society (BTS) developed a rule (BTSr) based on severity criteria to predict short term mortality in adults admitted to hospital with community acquired pneumonia (CAP). However, neither the BTSr nor a recent modification of it (mBTSr) have been validated in the UK. A case-control study was conducted in a typical UK population to determine the clinical factors predictive of mortality and to assess the performance of these rules. METHODS: Cases were drawn from all patients with CAP who died in 1997 in five large hospitals in the Mid Trent area. Controls were randomly selected from survivors. Factors associated with mortality were identified following review of medical case notes and performance of the severity prediction rules assessed. RESULTS: Age >65 years, temperature <37 degrees C, respiratory rate >24 breaths/min, mental confusion, urea concentration of >7 mmol/l, sodium concentration of <135 mmol/l, and the presence of a pleural effusion, all determined on admission, were independently associated with in-hospital mortality on multivariate analysis. The BTSr was 52% sensitive and 79% specific in predicting death while the mBTSr displayed 66% sensitivity and 73% specificity. CONCLUSIONS: The value of three of the four factors (presence of mental confusion, raised respiratory rate, raised urea) used in the mBTSr as predictors of mortality is confirmed. However, the BTSr and mBTSr did not perform as well in this validation study which included a high proportion (48%) of elderly patients (> or =75 years) compared with the derivation studies.

Adolescent↗
PubMed1999

How do general practitioners respond to reports of abnormal chest X-rays?

General practitioners (GPs) in the UK have long had direct access to hospital radiological services, which in theory shortens investigation time and improves the quality of service. Chest X-rays (CXRs) account for a substantial proportion of requests, and we investigated what happened when an abnormality was detected. In one year, 204 GPs in the Nottingham area requested CXRs in 605 patients. 362 were reported normal, 165 abnormal but hospital follow-up not indicated and 71 abnormal with radiological follow-up or hospital referral indicated (mass lesion suspicious of tumours 27, infective shadowing 35, other 9). 64 of the 71 were seen in hospital within three months, and in those with suspected cancer the median time to follow-up was 20 days. These results show that GPs do act on the results of abnormal CXRs, but only 37% of those with a mass suspicious of cancer were seen in hospital within two weeks as recommended by the British Thoracic Society. Time might be saved if GPs agreed to direct referral from the radiology department to respiratory physicians.

Adolescent↗
PubMed1998

The effects of ethnicity on disease patterns in 472 Orientals with systemic lupus erythematosus.

OBJECTIVE: To determine the effects of ethnicity on disease manifestations in Oriental patients with systemic lupus erythematosus (SLE) and to describe the risk of developing renal or central nervous system (CNS) involvement with time. METHODS: A retrospective study of 472 patients with SLE seen at the only Rheumatology Unit in Singapore. The effect of ethnicity on selected disease manifestations at diagnosis was assessed after adjusting for demographic variables using multiple logistic regression. The probability of developing selected disease manifestations with time was determined using the Kaplan-Meier product limit method. RESULTS: At diagnosis, Malays had a higher risk of renal or CNS involvement than Chinese (OR 2.26, 95% CI 1.21 to 4.21, and OR 3.07, 95% CI 1.01 to 9.34, respectively), and Indians a lower risk of malar rash and a higher risk of oral ulcers than Chinese (OR 0.30, 95% CI 0.13 to 0.68, and OR 2.90, 95% CI 1.45 to 7.34, respectively). The prevalence of renal or CNS involvement in the entire cohort increased with time, reaching 75.6% (95% CI 66.1% to 85.0%) and 16.7% (95% CI 11.7% to 21.6%), respectively, after 18 years of disease. CONCLUSION: Ethnicity influenced disease manifestations at diagnosis in this cohort of Oriental patients with SLE. Renal or CNS involvement developed in previously unaffected patients up to 18 years after diagnosis, highlighting the need for continued vigilance in patients with lupus.

Adolescent↗