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Biomedical subjects

S H Lim

Publications and source records attributed to S H Lim.

At least 163 records · Page 9Linked to original sources
PubMed1990

Use of computers in quality assurance of laboratory testing.

Implementation of comprehensive internal quality control programmes and participation in external quality assessment schemes to monitor analytical performance of laboratory tests have been widely accepted as an essential and integral part of good laboratory practice. As these programmes involve a great deal of repetitive statistical calculations and graphic presentation of data on quality control materials, many laboratories and practically all organisers of inter-laboratory quality assessment schemes increasingly rely on computers to handle the burdensome processing of data and to provide timely feedback in a manner that is easily understood and readily interpreted by analytical staff. However, in spite of the best effort to ensure reliable analytical performance, spurious and misleading results can still occur as a result of non-analytical errors which are not readily detected by methods designed to monitor the quality of analytical process. The use of sophisticated computer system has enabled our laboratory to check for the existence of some of these errors. This paper describes the application of computers in a variety of internal and external quality assessment programmes and demonstrates the usefulness of retrieving patients' cumulative test results and at the same time performing delta or percentage difference checks on such data in the detection of non-analytical errors and unexpected variations in results. The role of the computer in minimising transcription errors, reducing turn-around time of testing and reporting, as well as improving the quality of laboratory reports is also mentioned.

Clinical Laboratory Information Systems↗
PubMed1990

Allogeneic bone marrow transplantation for acute non-lymphoblastic leukaemia--the Singapore experience.

Eleven patients with acute non-lymphoblastic leukaemia (ANNL) underwent allogeneic bone marrow transplant (BMT) from the period, September 1985 to June 1989 in the Singapore General Hospital. Five of the six patients (83%) transplanted in the first remission are presently alive; three greater than 2.5 years after the transplant. Two of these three patients are enjoying disease free survival; the other had chronic graft versus host disease but well controlled with treatment. One of the six patients relapsed from his disease at Day 252 post-transplanted and died 8 months later. Four patients who were transplanted in the first untreated relapse and one in second remission have died; three from early post-transplant complications and two from relapse. The results of allogenic BMT in patients with ANNL in first remission in this study appear encouraging and are superior to conventional chemotherapy. Allogeneic BMT should be considered as the treatment of choice in selected groups of individuals with ANNL. (Abbrev.: BMT = Bone marrow transplant; ANNL = Acute non-lymphoblastic leukaemia; GVHD = Graft vs Host Disease; VOD = Veno-occlusive disease)

Adolescent↗
PubMed1990

Bone marrow transplantation for treatment of chronic myelogenous leukaemia (CML)--preliminary experience in Singapore.

Chronic Myelogenous Leukaemia (CML) is a clonogeneic disease with the Philadelphia (Ph') chromosome as a cytogenetic marker. Conventional therapy rarely leads to cure in CML. Treatment of CML by bone marrow transplantation (BMT) is thus a reasonable alternative. This study reports on nine patients in chronic phase CML who were given allogeneic bone marrow transplantation with bone marrow cells from HLA identical siblings. There were 5 males and 4 females. Median age was 25 years (range 15-33 years). Median time from diagnosis to BMT was 8 months (range 25 to 48 months). Conditioning regimens: (i) 4 patients received cyclophosphamide 60 mgm/kg x 2 days and Total Body Irradiation (TBI) 200 rads x 6 doses x 3 days. (ii) 5 patients received busulphan 4 mgm/kg per day x 4 days followed by cyclophosphamide 60 mgm/kg x 2 days. Cyclosporin A (CSA) and methotrexate (MTX) was administered for Graft-Versus-Host-Disease (GVHD) prophylaxis in 8 patients; one patient received CSA and prednisolone. Median time for engraftment and for peripheral blood granulocytes to reach more than 500/ul was 18 days (range 12-30 days). Median time for platelet count to reach more than 20,000/ul was 25.5 days (range 15-30 days). 33% of patients developed acute GVHD of Grade II and above. The acturial survival of the 9 patients is 46%. Eight of 9 patients transplanted had two or more risk factors which adversely affect prognosis in CML. Four patients are alive and in remission at 562, 386, 46 and 46 days post-BMT respectively.

Adolescent↗
PubMed1990

Acute sympathotonic orthostatic hypotension with recovery.

We describe a 30 year-old female who presented with severe orthostatic hypotension despite appropriate compensatory tachycardia on standing, following a viral infection. Clinical assessment and laboratory evaluation failed to detect other causes of her illness besides sympathotonic orthostatic hypotension. She responded to fludrocortisone and recovered completely after 3 months. We postulate that her acute reversible illness was due to a post-viral immunological response selectively affecting the alpha adrenergic receptors subserving the post-ganglionic sympathetic vasomotor fibres.

Acute Disease↗
PubMed1990

Secondary syphilis presenting with optic perineuritis and uveitis.

We describe a 40 year-old man with optic perineuritis due to secondary syphilis. This condition which is due to inflammation of the optic nerve sheath is often mistaken for papilloedema or papillitis. We discuss its diagnosis and stress the importance of recognising it because it is easily treated by a course of Penicillin.

Adult↗
PubMed1989

A simple adherence test for detection of IgM antibodies in typhoid.

A simple adherence test to detect IgM antibodies in patients with typhoid is described. The test utilises the IgM-"capture" approach, in which the test serum is applied to microtitration plate wells previously coated with anti-human IgM, followed by application of a stained Salmonella typhi antigen suspension which shows adherence in positive cases. By this test, 58 (95%) of 61 sera from confirmed cases of typhoid possessed IgM antibodies to the H or O or both antigens of S. typhi. In patients for whom a diagnosis of typhoid was based only on a significant Widal-test titre, 31 (41%) of 76 sera had IgM antibodies to the H or O or both antigens of S. typhi. Some cross-reactivity of the IgM antibodies was detected, especially with the O antigens of S. paratyphi A and B. A total of 82 sera from non-typhoidal fevers (leptospirosis, typhus, dengue fever) showed no reactivity in this test. In normal sera there was no detectable IgM to the O antigen of S. typhi and only a small number (3.9%) had low levels of IgM to the H antigen. The significance and potential importance of this simple, sensitive, specific and economical test is discussed.

Antibodies, Bacterial↗
PubMed1989

Acquired platelet dysfunction with eosinophilia: review of seven adult cases.

Seven adults with acquired platelet dysfunction with eosinophilia presented with histories of spontaneous bruising and three also had moderate thrombocytopenia. Six patients had platelet function tests performed and all showed variable storage pool defects. When assayed, IgE concentrations were raised. Although only two patients had parasites isolated in their stools, all seven responded to antihelminth treatment. It is speculated that the IgE response to parasites mediates mast cell degranulation, which leads to in vivo platelet activation.

Adult↗
PubMed1989

Graft-versus-host disease following sibling allogeneic bone marrow transplantation--the Singapore experience.

Fourteen patients with haematological malignancies received allogeneic bone marrow transplantation from Major Histocompatility Complex compatible siblings. Five (35.7%) patients developed mild and 4 (28.6%) severe graft-versus-host disease (GVHD). There were correlations between the age of recipient (p less than 0.05), the degree of haematological support (p less than 0.1) and GVHD. The effects of the Mixed Lymphocyte Culture reactivity, donor/recipient sex match, cyclosporin A levels and the use of Total Parenteral Nutrition were not apparent. Two patients had relapses of their initial diseases. One of them did not develop any GVHD and the other only mild GVHD post bone marrow transplantation.

Adolescent↗
PubMed1989

Intramedullary spinal cord metastasis.

Intramedullary spinal cord metastasis (ISM) is uncommon. It is one of the causes of a noncompressive myelopathy in a patient with systemic cancer. It is very difficult to diagnose clinically and on myelogram. We found the Magnetic Resonance Imaging appearance very useful in its diagnosis. We report one proven case of ISM to illustrate the diagnostic and therapeutic problem.

Breast Neoplasms↗
PubMed1989

Syringomyelia with Arnold Chiari I malformation: a report of four cases.

4 cases of syringomyelia with type I Arnold Chiari malformation was seen presenting mainly with dissociated sensory loss, weakness of hands and upper motor neurone signs in the lower limbs. The first patient improved with posterior fossa decompression. The second and fourth patient appeared not to have improved after surgery, and the third case refused operation. One patient showed cord atrophy on myelogram presumably due to a collapse of the syrinx. One of the patients was unusual in that the syrinx extended down to segment T11. Magnetic resonance imaging of the posterior fossa and the cervical cord, to date, is the most useful procedure for diagnosis.

Adult↗
PubMed1989

A case of sarcoidosis presenting as cranial polyneuritis.

A Chinese female patient presented with cranial polyneuritis of unknown aetiology. Three years later, the diagnosis became obvious when she developed other features of sarcoidosis. This is the first reported local case of sarcoidosis presenting initially with nervous system involvement. It also highlighted sarcoidosis as a possible aetiology in cases of idiopathic cranial polyneuritis.

Cranial Nerve Diseases↗
PubMed1988

Mixed lymphocyte reactions do not predict severity of graft versus host disease (GVHD) in HLA-DR compatible, sibling bone marrow transplants.

Mixed lymphocyte reactions (MLRs) were measured in 25 HLA-A, B and DR compatible sibling bone marrow transplants. Only four of 25 MLRs were positive and in these the low reactivity was of doubtful clinical importance. There was no correlation between MLR and the subsequent development or severity of graft versus host disease (GVHD). A survey of bone marrow transplant units in the United Kingdom showed that most centres perform HLA-DR typing as well as an assessment of the MLR. Factors other than histocompatibility are important in the pathogenesis of GVHD and the data from this study suggest that conventional MLRs can be omitted in HLA-A, B and DR compatible sibling bone marrow transplants.

Adult↗
PubMed1988

Locked jaw in polymyalgia rheumatica.

Polymyalgia rheumatica is a common disease affecting the elderly population. Symptoms and signs are often nonspecific, including pain and stiffness in the proximal muscles, anorexia, fatigue, depression, weight loss, fever and temporal headaches. We would like to report a case of polymyalgia rheumatica with locked jaw, a feature yet unrecorded.

Aged↗
PubMed1986

Computers in clinical laboratory management in Singapore.

In 1974, an off-line mini-computer system was introduced in the Clinical Biochemistry Laboratories of the Government Department of Pathology in Singapore. With the resiting of the 24-hour emergency biochemistry laboratory on the same floor as the Haematology Department within the new Singapore General Hospital, an on-line computer system was installed in 1983 to serve both the emergency biochemistry and haematology laboratories. An almost identical on-line system was also purchased in 1984 to replace the aged off-line system at the Department of Pathology. A description of the new computer systems based on Eclipse S/140 computers and Medical Information Technology (Meditech) software using Meditech Interpretive Information System (MIIS) language will be given. The specific features required and the selection criteria for the on-line systems are also discussed. The systems are used for the acquisition and processing of all patient and test data of the laboratories, direct capture of data from automated instruments, generation of work schedules and laboratory reports, compilation of work done, workload and revenue statistics and a variety of other reports. Patient cumulative records and quality control statistics are available on a real-time basis, thus greatly facilitating enquiries on patient results and monitoring of analytical performance. Prior experience with an off-line system and careful planning have been helpful in greatly shortening the preparatory period required for the smooth implementation of the on-line systems. Use of the systems has significantly improved laboratory management and has resulted in improved quality, and higher efficiency and productivity.

Chemistry, Clinical↗
PubMed1981

F1-ATPase of Micrococcus lysodeikticus is not a glycoprotein.

It has been claimed (Andreu, JM, Warth, R. and Muñoz, E. (1978) FEBS Letter, 86, 1-5) that the F1-ATPase of Micrococcus lysodeikticus is a glycoprotein containing mannose and glucose as the principal sugars. Even after extensive purification of M. lysodeikticus F1-ATPase by DEAE-Sephadex A25 chromatography, carbohydrate contents varying from 2.7 to 10.8% have been found. Concanavalin A-reactive components corresponding to the succinylated lipomannan have been detected and separated from the ATPase in purified F1 preparations by immunoelectrophoresis (rocket and two-dimensional) through agarose gels containing concanavalin A. Passage of the purified F1-ATPase through concanavalin A-Sepharose 4B columns removed the carbohydrate component(s) without loss of the specific activity of the ATPase. Mannose was the only sugar detectable by gas-liquid chromatography of the F1-ATPase before Con A-Sepharose 4B chromatography and it was completely eliminated after chromatography. No qualitative or quantitative changes in the subunit (alpha, beta, gamma, delta and epsilon) profiles were detectable when the sodium dodecyl sulfate polyacrylamide gels were scanned by densitometry of F1-ATPase before and after Con A-Sepharose 4B chromatography. We conclude that there is no evidence of carbohydrate covalently linked to this F1-ATPase and that this membrane protein is not a glycoprotein. The presence of carbohydrate is attributable to contamination with lipomannan.

Adenosine Triphosphatases↗