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Biomedical subjects

M K Lim

Publications and source records attributed to M K Lim.

At least 19 recordsLinked to original sources

Complementary and alternative medicine use in multiracial Singapore.

OBJECTIVE: To determine the prevalence of complementary and alternative medicine (CAM) use in Singapore, the factors influencing CAM use, and the attitudes, beliefs and perceptions of the general population towards CAM. DESIGN: An interviewer-administered questionnaire survey in a housing estate with demographic and socioeconomic characteristics closely matching that of Singapore. RESULTS: 76% (95% C.I. 73.9-77.9%) used CAM over a 12-month period. Females were 2.1 times (95% C.I. 1.3-3.4) more likely than males to use CAM. Chinese (84%) were the most frequent users, followed by Malays (69%) and Indians (69%), with adjusted odds ratios of 0.4 (95% C.I. 0.2-0.7) for Malays and 0.4 (95% C.I. 0.2-0.8) for Indians. Traditional Chinese Medicine (88%) was the most widely used form of CAM, followed by Traditional Malay (Jamu) Medicine (8%) and Traditional Indian (Ayuverdic) Medicine (3%). Similar to western studies, CAM was more likely to be used for maintenance of health than for treatment of illness. Different from western studies, CAM use was not independently associated with household income, marital status, age and education. Seventy-four percent did not discuss their use of CAM with their western-trained doctors. CONCLUSIONS: The high prevalence of CAM use in multi-racial Singapore suggests the same may be true in other Asian countries. Western-trained doctors need to understand CAM better and communicate more with their patients regarding CAM use. The lack of a scientific evidence base for most forms of CAM notwithstanding, its ubiquitous use worldwide is something that governments and the medical profession cannot afford to ignore.

Adult↗

Appropriate use of personal protective equipment among healthcare workers in public sector hospitals and primary healthcare polyclinics during the SARS outbreak in Singapore.

BACKGROUND: Singapore was affected by an outbreak of severe acute respiratory syndrome (SARS) from 25 February to 31 May 2003, with 238 probable cases and 33 deaths. AIMS: To study usage of personal protective equipment (PPE) among three groups of healthcare workers (HCWs: doctors, nurses, and administrative staff), to determine if the appropriate PPE were used by the different groups and to examine the factors that may determine inappropriate use. METHODS: A self-administered questionnaire survey of 14,554 HCWs in nine healthcare settings, which included tertiary care hospitals, community hospitals, and polyclinics, was carried out in May-July 2003. Only doctors, nurses, and clerical staff were selected for subsequent analysis. RESULTS: A total of 10 236 valid questionnaires were returned (70.3% response); 873 doctors, 4404 nurses, and 921 clerical staff were studied. A total of 32.5% of doctors, 48.7% of nurses, and 77.1% of the administrative staff agreed that paper and/or surgical masks were "useful in protecting from contracting SARS". Among this group, 23.6% of doctors and 42.3% of nurses reported working with SARS patients. The view that a paper and/or surgical mask was adequate protection against SARS was held by 33.3% of doctors and 55.9% of nurses working at the A&E unit, 30.5% of doctors and 49.4% of nurses from medical wards, and 27.5% of doctors and 37.1% of nurses from intensive care units. Factors which predicted for agreement that paper and/or surgical masks were protective against SARS, included HCW's job title, reported contact with SARS patients, area of work, and Impact Events Scale scores. CONCLUSION: A variety of factors determine appropriate use of personal protective equipment by HCWs in the face of a major SARS outbreak.

Administrative Personnel↗

Transforming Singapore health care: public-private partnership.

Prudent health care policies that encourage public-private participation in health care financing and provisioning have conferred on Singapore the advantage of flexible response as it faces the potentially conflicting challenges of becoming a regional medical hub attracting foreign patients and ensuring domestic access to affordable health care. Both the external and internal health care markets are two sides of the same coin, the competition to be decided on price and quality. For effective regulation, a tripartite model, involving not just the government and providers but empowered consumers, is needed. Government should distance itself from the provider role while providers should compete - and cooperate - to create higher-value health care systems than what others can offer. Health care policies should be better informed by health policy research.

Delivery of Health Care, Integrated↗

Quest for quality care and patient safety: the case of Singapore.

Quality of care in Singapore has seen a paradigm shift from a traditional focus on structural approaches to a broader multidimensional concept which includes the monitoring of clinical indicators and medical errors. Strong political commitment and institutional capacities have been important factors for making the transition. What is still lacking, however, is a culture of rigorous programme evaluation, public involvement, and patient empowerment. Despite these imperfections, Singapore has made considerable strides and its experience may hold lessons for other small developing countries in the common quest for quality care and patient safety.

Disease Management↗

Cosmic rays: are air crew at risk?

This article reviews the current knowledge about cosmic rays and their possible effects on health of air crew, discusses research directions necessary for establishing and measuring the risks, and highlights the need for physicians and air crew to be informed, despite the inconclusiveness of the evidence. A literature review of computerised medical and scientific databases was carried out. Recent reports highlighting increased incidence of cancer among airline pilots and cabin crew have renewed concerns about possible exposure to harmful levels of cosmic radiation at altitude. Such low energy ionising radiation has been shown to cause double stranded DNA deletions and induce genomic instability in human chromosomes. In the field of microelectronics, cosmic rays have been shown to cause "hard" and "soft" errors in computer microchips, in a dose-response fashion with increasing altitude. Pregnant cabin crew members are of special concern. Although the epidemiological evidence is still inconclusive, we know enough to warrant a cautionary stance. The European Union (EU) leads the way in legislation.

Aerospace Medicine↗

A murine dopamine neuron-specific cDNA library and microarray: increased COX1 expression during methamphetamine neurotoxicity.

Due to brain tissue heterogeneity, the molecular genetic profile of any neurotransmitter-specific neuronal subtype is unknown. The purpose of this study was to purify a population of dopamine neurons, construct a cDNA library, and generate an initial gene expression profile and a microarray representative of dopamine neuron transcripts. Ventral mesencephalic dopamine neurons were purified by fluorescent-activated cell sorting from embryonic day 13.5 transgenic mice harboring a 4.5-kb rat tyrosine hydroxylase promoter-lacZ fusion. Nine-hundred sixty dopamine neuron cDNA clones were sequenced and arrayed for use in studies of gene expression changes during methamphetamine neurotoxicity. A neurotoxic dose of methamphetamine produced a greater than twofold up-regulation of the mitochondrial cytochrome c oxidase polypeptide I transcript from adult mouse substantia nigra at 12 h posttreatment. This is the first work to describe a gene expression profile for a neuronal subtype and to identify gene expression changes during methamphetamine neurotoxicity.

3,4-Dihydroxyphenylacetic Acid↗

Serum ferritin as a serologic marker of activity in systemic lupus erythematosus.

To investigate the relationship between serum ferritin and disease activity in systemic lupus erythematosus (SLE), we enrolled 128 patients with SLE (18 males and 110 females). Twenty-eight patients (2 males and 26 females) with rheumatoid arthritis (RA) served as controls. The SLE patients were subdivided into three groups according to Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) scores: groups A (0-5), B (6-9), and C (> or =10). We prospectively evaluated 48 SLE patients before and after treatment. Serum ferritin and anti-dsDNA antibody were measured by radioimmunometric assay. C-reactive protein (CRP) was measured quantitatively by immunonephelometry. Complements 3 and 4 (C3 and C4) were measured by nephelometry. Serum levels of ferritin during the more active stage of SLE (group C) exceeded those of RA patients and patients at less active stages of SLE (groups A and B). There were no significant differences between RA patients and groups A and B. Serum ferritin was elevated especially in serositis and hematologic manifestation. In this prospective study, changes in SLEDAI scores before and after treatment correlated significantly with serum ferritin levels and inversely to C3 and C4 levels. We confirm that serum ferritin levels can be a useful marker of disease activity in SLE patients.

Adult↗

Construction of long-transcript enriched cDNA libraries from submicrogram amounts of total RNAs by a universal PCR amplification method.

Here we report a novel design of linker primer that allows one to differentially amplify long tracts (average 3.0 kb with size ranges of 1-7 kb) or short DNAs (average 1.5 kb with size ranges of 0.5-3 kb) from a complex mixture. The method allows one to generate cDNA libraries enriched for long transcripts without size selection of insert DNAs. One representative library from newborn kidney includes 70% of clones bearing ATG start codons. A comparable library has been generated from 20 mouse blastocysts, containing only approximately 40 ng of total RNA. This universal PCR amplification scheme can provide a route to isolate very large cDNAs, even if they are expressed at very low levels.

Animals↗

Does umbilical vein catheterization lead to portal venous thrombosis? Prospective US evaluation in 100 neonates.

PURPOSE: To establish, by means of serial ultrasonography (US), the incidence and natural history of neonatal portal venous thrombosis associated with catheterization of the umbilical vein and to evaluate the potential risk factors predisposing patients to thrombus formation. MATERIALS AND METHODS: Neonates who had undergone umbilical vein catheterization were studied. US was performed at 2-7-day intervals, before and after the removal of the catheter, until clot resolution or hospital discharge. The presence of portal venous thrombosis and temporal evolution were noted, and various risk factors were analyzed. RESULTS: US demonstrated clinically silent portal venous thrombosis in 43 (43%) of 100 neonates. Follow-up US revealed complete or partial resolution in 20 (56%) of 36 babies. A significant (P =.024) correlation was found between the initial size of the thrombi and spontaneous clot resolution. Statistically significant risk factors were catheterization for more than 6 days (P =.001) and transfusion (P =.019). CONCLUSION: Portal venous thrombosis is frequently associated with the placement of an umbilical venous catheter, and spontaneous resolution is expected in many cases. The duration of catheter placement should be minimized, and US monitoring is recommended as a guide to catheter removal.

Catheterization, Peripheral↗

Exposure of airline pilots and cabin crew to cosmic radiation during flight--what's the fuss?

The International Commission on Radiological Protection (ICRP) had in 1990 recommended that civilian aircrew be classified as being occupationally exposed to low-dose ionizing radiation, in view of their increased exposure to cosmic rays at altitude. In 2000, the European Union had gone ahead with legislation which requires all European airlines to monitor cosmic radiation levels during flight and to inform aircrew of the possible health risks. However, the evidence for a causal link between cosmic radiation exposure and health risks remains elusive despite recent findings of increased cancer incidence among airline pilots and cabin crew. The inconclusiveness of the evidence notwithstanding, there are compelling reasons for adopting a prudent and precautionary stance.

Aerospace Medicine↗

Genome-wide expression profiling of mid-gestation placenta and embryo using a 15,000 mouse developmental cDNA microarray.

cDNA microarray technology has been increasingly used to monitor global gene expression patterns in various tissues and cell types. However, applications to mammalian development have been hampered by the lack of appropriate cDNA collections, particularly for early developmental stages. To overcome this problem, a PCR-based cDNA library construction method was used to derive 52,374 expressed sequence tags from pre- and peri-implantation embryos, embryonic day (E) 12.5 female gonad/mesonephros, and newborn ovary. From these cDNA collections, a microarray representing 15,264 unique genes (78% novel and 22% known) was assembled. In initial applications, the divergence of placental and embryonic gene expression profiles was assessed. At stage E12.5 of development, based on triplicate experiments, 720 genes (6.5%) displayed statistically significant differences in expression between placenta and embryo. Among 289 more highly expressed in placenta, 61 placenta-specific genes encoded, for example, a novel prolactin-like protein. The number of genes highly expressed (and frequently specific) for placenta has thereby been increased 5-fold over the total previously reported, illustrating the potential of the microarrays for tissue-specific gene discovery and analysis of mammalian developmental programs.

Amino Acid Sequence↗

Pulmonary atresia with intact ventricular septum percutaneous radiofrequency-assisted valvotomy and balloon dilation versus surgical valvotomy and Blalock Taussig shunt.

OBJECTIVE: We compared the result of radiofrequency (RF)-assisted valvotomy and balloon dilation with closed surgical valvotomy and Blalock Taussig (BT) shunt as primary treatment in selected patients with pulmonary atresia and intact ventricular septum (PA-IVS). BACKGROUND: Patients with PA-IVS who have mild to moderate hypoplasia of the right ventricle (RV) and patent infundibulum have the greatest potential for complete biventricular circulation. The use of RF or laser wires to perforate the atretic valve followed by balloon dilation provides an alternative to surgery. METHODS: Between May 1990 and March 1998, 33 selected patients underwent either percutaneous RF valvotomy and balloon dilation (group 1, n = 21; two crossed over to group 2) or surgical valvotomy with concomitant BT shunt (group 2, n = 14). Second RV decompression by balloon dilation or right ventricular outflow tract (RVOT) reconstruction were performed if necessary. Patients who remained cyanosed were subjected to transcatheter trial closure of the interatrial communication. Partial biventricular repair was offered to those with inadequate growth of the RV. RESULTS: The primary procedure was successful in 19 patients in group 1. There was one in-hospital death and two late deaths. Of the remaining 16 survivors, 12 achieved complete biventricular circulation, 7 of whom required no further interventions. Two patients required repeat balloon dilation, 1 RVOT reconstruction and 2 transcatheter closure of interatrial communication. Two patients underwent partial biventricular repair. In group 2, there were 3 in-hospital deaths after the primary procedure and 1 patient died four months later. All survivors (n = 10) required a second RV decompression, 8 by balloon dilation and 2 by RVOT reconstruction, after which, two patients died. Of the final 8 survivors, 7 achieved complete biventricular circulation, 5 after coil occlusion of the BT shunt and 2 after closure of interatrial communication. CONCLUSIONS: Radiofrequency valvotomy and balloon dilation is more efficacious and safe compared with closed pulmonary valvotomy and BT shunt in selected patients with PA-IVS.

Adolescent↗

Eleven densely clustered genes, six of them novel, in 176 kb of mouse t-complex DNA.

Targeted sequencing of the mouse t-complex has started with a 176-kb, gene-rich BAC localized with six PCR-based markers in inversion 2/3 of the highly duplicated region. The sequence contains 11 genes recovered primarily as cDNAs from early embryonic collections, including Igfals (previously placed on chromosome 17), Nubp2 (a fully characterized gene), Jsap1 (a JNK-binding protein), Rsp29 (the mouse homologue of the rat gene), Ndk3 (a nucleoside diphosphate kinase), and six additional putative genes of unknown function. With 50% GC content, 75% of the DNA transcribed, and one gene/16.0 kb (on average), the region may qualify as one of the most gene-dense segments in the mouse genome and provides candidates for dosage-sensitive phenotypes and mouse embryonic lethals mapped to the vicinity.

Animals↗

Fetal acalvaria with amniotic band syndrome.

A case of amniotic band syndrome (ABS) presenting with acalvaria is reported. ABS includes a spectrum of non-genetic anomalies, varying from simple digital band constriction to major craniofacial and visceral defects, and even fetal death. Acalvaria is a rare congenital malformation characterised by the absence of the dome-like superior portion of the cranium comprising the frontal, parietal, and occipital bones and dura mater, in the presence of a normal skull base and facial bones with complete cranial contents. No two cases are the same. Acrania or absence of the flat skull bones with disorganised cerebral hemispheres have been reported in the presence of amniotic bands. ABS is an aetiological factor in acalvaria. Appropriate counselling for affected families needs to be given after prenatal diagnosis.

Amnion↗

Systemic lupus erythematosus: brain MR imaging and single-voxel hydrogen 1 MR spectroscopy.

PURPOSE: To evaluate the usefulness of magnetic resonance (MR) imaging and hydrogen 1 MR spectroscopy in the detection of brain involvement in patients with systemic lupus erythematosus (SLE) with or without neuropsychiatric symptoms. MATERIALS AND METHODS: Twenty-six patients who had SLE with (n = 17) or without (n = 9) neuropsychiatric symptoms were examined at MR imaging and (1)H MR spectroscopy. The voxel was placed in the basal ganglia and peritrigonal white matter. Eight healthy volunteers were included. RESULTS: Five of nine patients with major neuropsychiatric symptoms and one of eight patients with minor neuropsychiatric symptoms had abnormal MR imaging findings. (1)H MR spectroscopy showed a significantly decreased N:-acetylaspartate-creatine (Cr) ratio in the basal ganglia and an increased choline-Cr ratio in the peritrigonal white matter in patients with major symptoms compared with those with minor symptoms, those without symptoms, and healthy control subjects. Among patients with major symptoms, there was no difference in metabolite ratios between those with and those without abnormal MR imaging findings. Among patients with normal MR imaging findings, abnormal spectral changes were observed only in those with major neuropsychiatric symptoms. In patients without neuropsychiatric symptoms, results of (1)H MR spectroscopy and MR imaging were normal. CONCLUSION: In patients with SLE, (1)H MR spectroscopic findings seem to reflect the cerebral metabolic disturbance related to the severity of the neuropsychiatric symptoms and are not related to the presence of abnormal MR imaging findings.

Adolescent↗

Large-scale cDNA analysis reveals phased gene expression patterns during preimplantation mouse development.

Little is known about gene action in the preimplantation events that initiate mammalian development. Based on cDNA collections made from each stage from egg to blastocyst, 25438 3'-ESTs were derived, and represent 9718 genes, half of them novel. Thus, a considerable fraction of mammalian genes is dedicated to embryonic expression. This study reveals profound changes in gene expression that include the transient induction of transcripts at each stage. These results raise the possibility that development is driven by the action of a series of stage-specific expressed genes. The new genes, 798 of them placed on the mouse genetic map, provide entry points for analyses of human and mouse developmental disorders.

Animals↗