Presynaptic neuromuscular transmission defect in the Miller Fisher syndrome.
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Action Potentials↗
Biomedical subjects
L L Lim
Publications and source records attributed to L L Lim.
Recovery of precious metals by an electrochemical deposition method.
Conversion of soluble precious metals into a solid form for further reuse was studied by using an electrochemical deposition approach. It was found that the metal recovery followed a first-order reaction kinetics. The distance between the electrodes had no much impact on the recovery, while higher mixing led to faster kinetics. The presence of humic acid (HA) with lower concentration (<20mg l (-1)) did not have impact on the recovery. When its concentration was increased to 50 mg l (-1), it decreased the metal reduction. Presence of ethylene diamine tetraacetic acid (EDTA) and ionic strength slightly reduced the copper recovery rate. Around 50% removal of for HA and EDTA was achieved. In the competing environment, metal recovery was in the following order: silver>lead>copper. X-ray photoelectron spectroscopic and scanning electronic microscopic analysis of the reduced metals demonstrated that the depositions were composed of mainly elemental metals together with their oxides which were due to the oxidation.
Chelating Agents↗
Key factors in chemical reduction by hydrazine for recovery of precious metals.
Most of the commonly used metal waste treatment approaches only allow removal of metals which are ultimately discarded as sludge and do not permit the reuse of the metals, resulting in a waste of raw materials. In this study, the recovery of precious metals of sliver and copper in a synthesized wastewater in batch reactors was investigated using a reduction method by hydrazine as the reducing agent. Recovery of metal ions was greatest at pH > 11. The presence of humic acid did not have negative effects on the recovery process. Varying dissolved oxygen levels in the hydrazine solution did not significantly affect the recovery of both metals while seeding and ageing processes resulted in an increase in the particle size of the solid obtained. Under competitive conditions between Cu2+ and Ag+ ions, the recovery of silver remained the same, while that of copper was enhanced.
Copper↗
Prophylactic lamivudine prevents hepatitis B reactivation in chemotherapy patients.
BACKGROUND: Chronic hepatitis B virus carriers receiving chemotherapy develop a high hepatitis B virus reactivation rate (38-53%) with a high mortality (37-60%). Few studies have characterized the efficacy of lamivudine in the treatment of chemotherapy-induced hepatitis B virus reactivation. AIM: To determine whether lamivudine prophylaxis reduces chemotherapy-induced hepatitis B virus reactivation and mortality. METHODS: The medical records of all hepatitis B surface antigen-positive patients with malignancy treated with chemotherapy since 1995 at the National University Hospital of Singapore were identified, and divided into those who received lamivudine prophylaxis before chemotherapy (P) and those who did not (NP). The parameters examined included gender, age, malignancy type, steroid usage, number of chemotherapy courses and regimens, follow-up duration and hepatitis B virus status. The outcome measures were hepatitis B virus reactivation (abrupt rise of serum alanine aminotransferase to > 200 IU/L) and reactivation death. Patients with primary hepatoma or liver metastasis were excluded. RESULTS: Thirty-five patients were identified: 16 in the P group and 19 in the NP group. The baseline characteristics of the two groups were similar. Seven of the 19 patients in the NP group and none of the 16 patients in the P group developed reactivation (36.8% vs. 0%, P=0.009). Six of the seven patients in the NP group who developed reactivation received lamivudine at that time, but five died (mortality, 71.4%), whilst no patient in the P group died from reactivation (P=0.064). CONCLUSIONS: Prophylactic lamivudine appears to prevent hepatitis B virus reactivation and its associated mortality in patients treated with chemotherapy. This should be confirmed with prospective studies.
Adult↗
Randomised controlled trial to change the hospital management of unstable angina.
OBJECTIVES: To examine the benefits of a guideline-based educational program to improve management of unstable angina pectoris (UAP) in hospital patients. DESIGN: Randomised controlled trial. SETTING: 37 public hospitals across New South Wales. PATIENTS: 1,872 patients admitted with a diagnosis of UAP between 1 February and 30 June 1996 (baseline survey), and 1,368 patients with the same diagnosis admitted between 1 July and 31 December 1998 (follow-up survey). INTERVENTION: Educational sessions run by local opinion leaders, presenting guidelines on management of UAP from the National Health and Medical Research Council and feedback on local practice using data from the baseline survey. Sessions were run between March and June 1998. MAIN OUTCOME MEASURES: Use of evidence-based practice, identified by review of medical records. RESULTS: Use of beta-blockers increased in intervention and control hospitals, although the increase was significant only in the former. Use of calcium-channel blockers decreased significantly in both intervention and control hospitals. However, the change in drug use between baseline and follow-up did not differ significantly between intervention and control hospitals. CONCLUSIONS: Despite some appropriate changes in drug use for UAP management between 1996 and 1998, there was no evidence that a guideline-based educational program was of benefit in changing management. This reaffirms the difficulty of changing doctors' behaviour through practice guidelines. Alternative methods of encouraging evidence-based practice should be considered.
Adrenergic beta-Antagonists↗
Accuracy of administrative data to assess comorbidity in patients with heart disease. an Australian perspective.
The objective of this study was to determine the accuracy of administrative data (by use of hospital discharge codes) for measuring comorbidity in patients with heart disease. One thousand seven hundred and sixty-five medical records of subjects admitted to hospital for AMI, unstable angina, angina pectoris, chronic IHD or heart failure were reviewed. The number and types of comorbidities were determined from the medical records (regarded as the "gold standard"). These were compared with the 10 discharge codes obtained from the hospital administrative records (referred to as the "administrative data"). The rate of false-negative and false-positive comorbidity diagnoses were determined. Twenty of the 21 comorbidities studied were underreported in the administrative data. For these 20 comorbidities, the median false-negative rate was 49.5% and ranged from 11% for diabetes to 100% for dementia. False-positive rates were low, less than 1.5%, except for chronic arrythmia (4.8%) and hypertension (4.2%). Mean percent agreement was high, ranging from 88% for hypertension to 100% for AIDS/HIV. Administrative data based on hospital discharge codes consistently underestimate the presence of comorbid conditions in our population. This has implications for administrators when estimating mortality, length of stay and disability. Researchers also need to be aware when using administrative data based on hospital discharge codes to assess subject's comorbidities that they may be widely underreported.
Aged↗
A prognostic index for 30-day mortality after stroke.
The objective of this study was to develop a simplified scoring system to predict 30-day mortality in patients with acute ischemic stroke. A retrospective cohort study was performed in a tertiary referral hospital in the Hunter Region of Australia. A prognostic index was created by assigning points to the variables in a Cox model. The index included impaired consciousness (5 points), dysphagia (3 points), urinary incontinence (4 points), admission body temperature higher than 36.5 degrees C (2 points), and hyperglycemia without a clinical history of diabetes (2 points). A score of 11 or more defined a high-risk group. The index achieved a sensitivity, specificity, and positive predictive value of 68%, 98% and 75%, respectively, in the derivation sample and 57%, 97% and 68%, respectively, in the validation sample. The results provide a simple risk stratification instrument for clinical research and practice. Further evaluation of the model in a prospective cohort is warranted
Aged↗
Quality of life: an index for identifying high-risk cardiac patients.
A sample of 945 cardiac patients admitted under emergency conditions completed a quality of life questionnaire 4 months post-discharge. Half (471) were randomly allocated to a group used to develop a logistic regression model to predict mortality and cardiovascular morbidity 8 months later. Age 65-85 years, ever having heart failure, experiencing another cardiovascular event since discharge, and low global quality of life (QOL) score were found to be predictive of these outcomes; an interaction between QOL and heart failure was also found. The model was used to formulate a risk index which was validated in the remaining 474 patients. The index defines four levels of increasing risk of adverse outcomes, with rates in the development and validation groups, respectively, of: low risk 4% and 9%; moderate risk 13% and 15%; high risk 31% and 33%; very high risk 52% and 40%. Scores in the emotional, physical and social QOL domains were also found to be predictive of adverse outcomes, suggesting that interventions in any of these areas may prove beneficial. The index may be useful for follow-up evaluation of cardiac patients.
Adult↗
Acetazolamide in women with catamenial epilepsy.
PURPOSE: Catamenial epilepsy is a condition characterized by an increase in seizures during particular phases of the menstrual cycle. The incidence of catamenial epilepsy varies widely, partly because of a lack of a universally adopted definition. Specific treatment options for these patients are limited. The use of acetazolamide (AZ) has been based largely on anecdotal reports demonstrating efficacy in small or poorly characterized populations. The purpose of this study was to analyze retrospectively the efficacy, safety profile, and tolerability of AZ in women with catamenial epilepsy. METHODS: Women with catamenial epilepsy identified from 1990 through 1999 were invited to participate in a retrospective telephone questionnaire addressing the relationship of seizures and the menstrual cycle and the use, efficacy, and adverse effects of AZ. Seizure outcome was classified as: seizure free (SF), significantly improved (SI), or not significantly improved (NSI). Responses to AZ were compared in women with different types of epilepsy and comparing continuous versus intermittent dosing using Fisher's exact tests. RESULTS: Twenty women were identified who had received or were currently taking AZ. The drug was given continuously in 55% and intermittently in 45% of patients. A > or =50% decrease in the seizure frequency was reported by 40% of subjects. Response rates were similar in generalized and focal epilepsy and in temporal and extratemporal epilepsy. There was no significant difference in effectiveness comparing continuous with intermittent dosing. A loss of efficacy over 6-24 months was reported by 15% of women. CONCLUSIONS: Despite our small sample and retrospective design, AZ appears to demonstrate efficacy for catamenial epilepsy.
Acetazolamide↗
Trends in the hospital management of unstable angina.
STUDY OBJECTIVE: To examine the hospital management of unstable angina (UAP) in 1996 and 1998, according to patient demographic variables and disease severity. DESIGN: Medical record review. SETTING: 37 hospitals across New South Wales, Australia, representative of the secondary and tertiary care hospitals in the State. PARTICIPANTS: All patients (or a random sample of patients) with UAP admitted to these hospitals during five months in 1996 and six months in 1998 (1872 and 1368 patients respectively). MAIN RESULTS: In the two years between 1996 and 1998, there was an increase in the use of beta blockers and a corresponding decrease in the use of calcium channel blockers, as well as a decrease in the use of intravenous nitrates. Those aged 75 or more were roughly half as likely as those aged less than 65 to be prescribed heparin, aspirin and heparin, beta blockers, intravenous nitrates, and only one third as likely to be offered coronary angiography in hospital. They were one and a half times as likely to be prescribed calcium channel blockers compared with the youngest age group. A similar pattern was seen for gender, where men were more likely than women to be given aspirin, aspirin and heparin, and coronary angiography, and less likely to be given calcium channel blockers. Those with a past history were less likely, and those with more severe disease were more likely than others to be given most interventions. CONCLUSIONS: In view of the low use of evidence-based management of UAP among women and the elderly, it would seem appropriate for disease management guidelines to target these groups.
Adrenergic beta-Antagonists↗
Increased atherosclerosis in myeloperoxidase-deficient mice.
Myeloperoxidase (MPO), a heme enzyme secreted by activated phagocytes, generates an array of oxidants proposed to play critical roles in host defense and local tissue damage. Both MPO and its reaction products are present in human atherosclerotic plaque, and it has been proposed that MPO oxidatively modifies targets in the artery wall. We have now generated MPO-deficient mice, and show here that neutrophils from homozygous mutants lack peroxidase and chlorination activity in vitro and fail to generate chlorotyrosine or to kill Candida albicans in vivo. To examine the potential role of MPO in atherosclerosis, we subjected LDL receptor-deficient mice to lethal irradiation, repopulated their marrow with MPO-deficient or wild-type cells, and provided them a high-fat, high-cholesterol diet for 14 weeks. White cell counts and plasma lipoprotein profiles were similar between the two groups at sacrifice. Cross-sectional analysis of the aorta indicated that lesions in MPO-deficient mice were about 50% larger than controls. Similar results were obtained in a genetic cross with LDL receptor-deficient mice. In contrast to advanced human atherosclerotic lesions, the chlorotyrosine content of aortic lesions from wild-type as well as MPO-deficient mice was essentially undetectable. These data suggest an unexpected, protective role for MPO-generated reactive intermediates in murine atherosclerosis. They also identify an important distinction between murine and human atherosclerosis with regard to the potential involvement of MPO in protein oxidation.
Animals↗
Death and readmission in the year after hospital admission with cardiovascular disease: the Hunter Area Heart and Stroke Register.
OBJECTIVES: To compare outcomes one year after hospital admission for patients initially discharged with a diagnosis of acute myocardial infarction (AMI), other ischaemic heart disease (other IHD), congestive heart failure (CHF) or stroke. DESIGN: Cohort study. SETTING: Hunter Area Heart and Stroke Register, which registers all patients admitted with heart disease or stroke to any of the 22 hospitals in the Hunter Area Health Service in New South Wales. PATIENTS: 4981 patients with AMI, other IHD, CHF or stroke admitted to hospital as an emergency between 1 July 1995 and 30 June 1997 and followed for at least one year. MAIN OUTCOME MEASURES: Death from any cause or emergency hospital readmission for cardiovascular disease. RESULTS: In-hospital mortality varied from 1% of those with other IHD to 22% of those with stroke. Almost a third of all patients discharged alive (and 38% of those aged 70 or more) had died or been readmitted within one year. This varied from 22% of those with stroke to 49% of those with CHF. The causes of death and readmission were from a spectrum of cardiovascular disease, regardless of the cause of the original hospital admission. CONCLUSIONS: Data from this population register show the poor outcome, especially with increasing age, among patients admitted to hospital with cardiovascular disease. This should alert us to determine whether optimal secondary prevention strategies are being adopted among such patients.
Aged↗
Stated and actual management of acute myocardial infarction among different specialties.
OBJECTIVES: To examine the variation in stated management of acute myocardial infarction (AMI) among clinicians of different specialties, and to compare stated with actual practice. DESIGN: Mail survey using a hypothetical case history, and review of medical records. SETTING: 47 public hospitals in New South Wales. SUBJECTS: 224 cardiologists, general/other physicians and general practitioners (GPs) who manage patients with AMI; 390 patients admitted for AMI between February and June 1996. OUTCOME MEASURES: Stated and actual use of treatments and investigations for AMI. RESULTS: Stated use of aspirin, thrombolysis and beta-blockers (95%-100%, 95%-100% and 80%-86%, respectively) was high in all three specialties. Cardiologists were significantly more likely than GPs to state use of heparin (87% v 57%; P < 0.001), ACE inhibitors (84% v 49%; P < 0.001) and echocardiography or gated pool heart scan (79% v 26%; P < 0.001). Stated use of nitrates by cardiologists was significantly lower compared with the other specialties (29% v 50% and 44%; P = 0.027). Actual use of aspirin was high (> 80%) in all specialties. Actual use of thrombolysis was similar to stated use after adjusting for factors such as time to hospital arrival and ST-segment elevation. There were substantial differences between stated and actual use. CONCLUSIONS: There were differences in practice patterns between and among clinicians of different specialties in NSW, consistent with findings from other countries. The high stated and actual use of aspirin and thrombolysis is encouraging.
Adult↗
Survival analysis for recurrent event data: an application to childhood infectious diseases.
Many extensions of survival models based on the Cox proportional hazards approach have been proposed to handle clustered or multiple event data. Of particular note are five Cox-based models for recurrent event data: Andersen and Gill (AG); Wei, Lin and Weissfeld (WLW); Prentice, Williams and Peterson, total time (PWP-CP) and gap time (PWP-GT); and Lee, Wei and Amato (LWA). Some authors have compared these models by observing differences that arise from fitting the models to real and simulated data. However, no attempt has been made to systematically identify the components of the models that are appropriate for recurrent event data. We propose a systematic way of characterizing such Cox-based models using four key components: risk intervals; baseline hazard; risk set, and correlation adjustment. From the definitions of risk interval and risk set there are conceptually seven such Cox-based models that are permissible, five of which are those previously identified. The two new variant models are termed the 'total time - restricted' (TT-R) and 'gap time - unrestricted' (GT-UR) models. The aim of the paper is to determine which models are appropriate for recurrent event data using the key components. The models are fitted to simulated data sets and to a data set of childhood recurrent infectious diseases. The LWA model is not appropriate for recurrent event data because it allows a subject to be at risk several times for the same event. The WLW model overestimates treatment effect and is not recommended. We conclude that PWP-GT and TT-R are useful models for analysing recurrent event data, providing answers to slightly different research questions. Further, applying a robust variance to any of these models does not adequately account for within-subject correlation.
Acute Disease↗
Where do developing World clinicians obtain evidence for practice: a case study on pneumonia.
There are few data on the practice of evidence based medicine in the developing world, nor on the actual sources of evidence that clinicians use in practice. To test the hypothesis that there was variation between and within developing countries in the proposed management of a patient with hospital acquired pneumonia, and that part of the variation can be explained by the sources of evidence used. Questionnaire responses to hypothetical case history. Investigators from 6 centres within the International Clinical Epidemiology Network (INCLEN) in China, Thailand, India, Egypt, and Kenya. Doctors chosen to represent primary and secondary hospital practice in the regions of the study centres. Investigations and initial treatments which would be ordered for a hypothetical 60-year-old woman who develops pneumonia 5 days after hospital admission, whether local data on antibiotic sensitivities are available and where information would be obtained to guide management. Chest x-ray and sputum gram stain/culture were consistently the most commonly ordered investigations, there being much greater variation in the initial treatment choices with either penicillin, a third-generation cephalosporin or aminoglycoside being the most popular choice. Textbooks were the commonest form of information source, and access to a library, textbooks and journals were statistically significantly associated with appropriate choice of investigations, but not treatment. Access to local antibiotic sensitivities was associated with appropriate initial treatment choice. Improving access to information in the literature and to local data may increase the practice of evidence-based medicine in the developing world.
Cross Infection↗
Psychosocial experiences of cardiac patients in early recovery: a community-based study.
OBJECTIVE: To report on the nature, incidence and severity of problems commonly experienced by cardiac patients in the early months of recovery, and to test the hypotheses that there exist differences in the incidences of these problems depending on age and sex. METHODS: 1124 emergency cardiac patients discharged from hospital with acute myocardial infarction, unstable angina, stable angina pectoris, chronic ischaemic heart disease or heart failure were surveyed 4 months after discharge. They were asked to indicate how often during the previous 2 weeks they had experienced each of a range of feelings and problems common to cardiac patients. RESULTS: A large proportion of patients reported experiencing problems in the areas of emotional reactions (70%), physical condition (79%), convalescence (67%) and relating to family and friends (63%). Severe problems were experienced especially in the physical and convalescence areas (43% and 44%, respectively). A greater proportion of patients diagnosed with heart failure experienced problems than those with other diagnoses, and these problems were more severe. Amongst myocardial infarction patients, a greater proportion of females than males reported severe problems in the emotional and physical areas, and patients 65 years and over were more likely than younger patients to report experiencing severe problems with physical condition. CONCLUSIONS: Many cardiac patients are experiencing psychosocial problems 4 months after hospital discharge, especially with physical activities and convalescence. A knowledge of the incidence and nature of these problems may help nurses to assist patients to validate their experiences.
Adaptation, Psychological↗
Differences in cardiac procedures among patients in metropolitan and non-metropolitan hospitals in New South Wales after acute myocardial infarction and angina.
An observational cohort study examined the difference in use of cardiac procedures during and after hospital admission for acute chest pain in 47 metropolitan or non-metropolitan hospitals across New South Wales (NSW). There were 3836 patients, represented by 4151 admissions to hospital after acute myocardial infarction (AMI), unstable angina or other angina. Follow up at 22 months was completed on 1695 patients. Patients admitted to metropolitan hospitals had higher rates of most cardiac procedures while in-patients than did patients in non-metropolitan hospitals. Odds ratios (95% confidence intervals) for the use of exercise stress tests, echocardiograms, nuclear studies and coronary angiography were 3.30 (1.38, 7.90), 9.34 (4.07, 21.44), 4.87 (2.08, 11.39) and 68.64 (17.29, 272.49), respectively, for patients with AMI and 1.93 (0.91, 4.12), 5.60 (1.60, 19.57), 3.51 (1.48, 8.33) and 38.57 (9.36, 158.94), respectively, for patients with unstable angina. Rates were similar between hospital types during the 22 months after discharge. The appropriateness of this large variation in resource use between metropolitan and non-metropolitan hospitals requires examination.
Adult↗
Mortality after acute myocardial infarction is lower in metropolitan regions than in non-metropolitan regions.
STUDY OBJECTIVES: To compare in-hospital mortality for acute myocardial infarction (AMI) between metropolitan and non-metropolitan hospitals after adjustment for patients' severity; to examine the role of the use of effective cardiac medications in the possible mortality difference between these types of hospital. DESIGN: Retrospective cohort study. SETTING: 47 acute public hospitals in metropolitan and non-metropolitan areas of New South Wales, Australia, taking part in the Acute Cardiac Care Project based on medical record review. PATIENTS: 1665 patients with principal discharge diagnosis of AMI from February to June 1996. MAIN RESULTS: There was no difference in crude mortality rate (assessed as seven day mortality) between metropolitan and non-metropolitan hospitals (11.0% compared with 10.7% respectively, p=0.893). After adjustment for severity in a logistic regression model, the odds of death in non-metropolitan hospitals was significantly higher than in metropolitan hospitals (odds ratio = 1. 90; 95% CI 1.21, 3.23). The addition of the use of effective cardiac medications to the model resulted in the difference between hospital type becoming non-significant (odds ratio=1.09; 95% CI 0.57, 2.07). CONCLUSIONS: In-hospital mortality in non-metropolitan hospitals was higher than that in metropolitan hospitals, after adjustment for patients' severity. This might partly be explained by the difference in use of effective cardiac medications between hospital type.
Acute Disease↗