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Biomedical subjects

L C Lim

Publications and source records attributed to L C Lim.

At least 37 records · Page 2Linked to original sources
PubMed1999

Psychiatric survey of offenders under criminal commitment in Singapore.

AIM OF STUDY: The study examined the demographic characteristic, pattern of psychiatric morbidity in offenders committed by Singapore courts and the effects of psychiatric recommendations on the disposal of these offenders. METHODS: A retrospective case-note study was done on all offenders committed by the courts from January 1987 to December 1988 to Woodbridge Hospital. A 23-item questionnaire was used to collect data from the offenders. RESULTS: There were 187 offenders in the study, 165 males and 22 females. The typical offender was Chinese, male, unemployed and suffered from schizophrenia. 63.1% of the offenders required treatment after commitment. 13.9% had no psychiatric disorder. At the end of commitment, charges were dropped in 25% of cases. Theft was the most common offense and this was followed by sexual offences (molestation, outrage of modesty, exhibitionism). Offenders with schizophrenia were more likely than the others to have committed violent offences. CONCLUSION: A large proportion of offenders were unwell at the time of the offence, the majority were suffering from schizophrenia. 13.9% had no psychiatric illness and charges were dropped in 25% indicating that the legal process could be further improved by providing additional psychiatric input to the courts so that offenders who exhibit abnormal or deviant behaviour may be appropriately dealt with.

Adolescent↗
PubMed1999

Child psychiatric consultations in a general hospital.

BACKGROUND: The referral pattern of child psychiatry was reviewed over a period of 3 years. The setting was a local general hospital with in-patient and out-patient adult psychiatric services. The cases studied were from out-patient based services rendered for children. OBJECTIVE: To draw a comparison between trends of referral from a study conducted locally in 1984 in a child guidance clinic. METHODS: A questionnaire was used to collect demographic information for children below 16 years. Medical records of patients seen between January 1992 and December 1994 were analysed. RESULTS: In our study, parental referrals topped the list of source of referrals compared to referrals from school health service in the study conducted in 1984. The conditions commonly seen remained the same, namely mental retardation, neurosis and adjustment reaction. CONCLUSION: Children were referred according to parent tolerance and acceptance of psychiatric help as well as behaviour.

Adjustment Disorders↗
PubMed1999

A 20-year-old man with eosinophilia and easy bruisability.

Acquired platelet dysfunction with eosinophilia is a rare, benign self-limiting disorder characterised by platelet dysfunction and an association with parasitic infections. A 20-year-old national serviceman who presented with easy bruising and spontaneous epistaxis is reported. Investigations revealed eosinophilia and an abnormal platelet function test similar to that seen in patients with Glanzmann's thrombasthenia infections. He also had evidence of hookworm infestation. Following a course of mebendazole, his symptoms and platelet dysfunction resolved. Hence, this disorder of acquired platelet dysfunction with eosinophilia should be considered in patients with bleeding disorders secondary to platelet dysfunction.

Adult↗
PubMed1998

A whole-blood assay for qualitative and semiquantitative measurements of CD69 surface expression on CD4 and CD8 T lymphocytes using flow cytometry.

A whole-blood flow cytometry-based assay was utilized to assess CD4 and CD8 T-lymphocyte activation in response to phytohemagglutinin (PHA) stimulation. T-lymphocyte activation was assessed by qualitative (percent CD69) and semiquantitative (anti-CD69 antibody binding capacity) measurements of CD69 surface expression. Whole-blood samples from 21 healthy and 21 human immunodeficiency virus (HIV)-infected (<500 absolute CD4 counts per mm3) individuals were stimulated with 20 microg of PHA per ml for 18 to 24 h. The proportions of activated CD4 and CD8 T lymphocytes expressing CD69 (percent CD69) and the levels of CD69 expression on each T-lymphocyte subset (anti-CD69 antibody binding capacity) were measured. By using this assay system, T-lymphocyte activation was impaired in both CD4 and CD8 T-lymphocyte subsets of HIV-infected individuals. The proportions of CD69-positive CD4 and CD8 T lymphocytes were 43 and 27% lower, respectively, in samples from HIV-infected individuals compared to samples from healthy individuals. Similarly, the levels of CD69 expression on each activated CD4 and CD8 T-lymphocyte subset were 48 and 51% lower, respectively. These results suggest that both qualitative and semiquantitative measurements of CD69 surface expression by flow cytometry can be used to assess T-lymphocyte activation.

Antigens, CD↗
PubMed1997

Rapid susceptibility testing of Candida albicans by flow cytometry.

The emerging magnitude of human fungal infections has renewed interest in developing rapid and standardized methods for susceptibility testing. We demonstrated that susceptibility testing of Candida albicans can be accomplished rapidly by using flow cytometry. Test results were available within 8 to 24 h after C. albicans isolates were incubated with amphotericin B, itraconazole, and flucytosine. This is an improvement of 24 to 60 h in the time to availability of susceptibility test results compared to the time to availability of National Committee for Clinical Laboratory Standards-recommended broth macrodilution test results. In addition, the flow cytometric endpoints, mean channel fluorescence, and number of fluorescence-labeled C. albicans cells were easy to interpret for greater sensitivity and reliability. Flow cytometry provides a more accurate means of obtaining antifungal susceptibility test results.

Acridine Orange↗
PubMed1997

Chylothorax: case report and review of literature.

Chylothorax is a relatively uncommon condition. We report a case of a 53-year-old Chinese man with chylothorax who presented with cough, breathlessness, loss of weight and generalised lymphadenopathy. He was initially diagnosed as having tuberculosis based on histology and cultures of the cervical lymph node. However, immunophenotyping of the pleural fluid by flow cytometry showed the presence of a monoclonal B cell population with Kappa light chain expression suggesting an underlying lymphoproliferative disorder. A repeat lymph node biopsy showed malignant lymphoma (follicular small cleaved type). In spite of aggressive measures which included bilateral tube thoracostomy drainage, a low fat diet, medium chain triglyceride diet, total parenteral nutrition, chemotherapy and mediastinal irradiation, his chylothorax persisted. Hence, we report a patient with persistent chylothorax and generalised lymphadenopathy who was subsequently diagnosed to have concurrent tuberculosis and malignant lymphoma. The literature on chylothorax is reviewed.

Biopsy↗
PubMed1996

Assessing the statistical power to detect linkage in a sample of 51 bipolar affective disorder pedigrees.

We used computer simulation method to address the question of power in an initial collaborative sample of 51 bipolar affective disorder pedigrees. Simulations were performed for all possible combinations using (1) two levels of diagnostic stringency, (2) three transmission models, (3) locus heterogeneity, and (4) different assumed phenocopy rates. Some of the factors affect the power to detect linkage are (1) the specification of the correct genetic model, (2) the degree of locus heterogeneity, and (3) the frequency of phenocopies. The first two assertions were supported by our simulation results, but varying the rates of phenocopy did not substantially alter the power of the sample until a critical point. However, it is important to point out that these results are dependent on the genetic models under study and on the use of the "correct" model (i.e., the one used to simulate the data). If we assume a dominant mode of inheritance and locus homogeneity, the power to detect linkage is 97.5% at a theta of .01. However, the power declines dramatically, to 60.5% and 14.7%, if only 75 and 50% of the families are linked, respectively. Locus heterogeneity has a similar effect on the power of the sample to exclude linkage. The relative lack of power in our data, in the presence of significant locus heterogeneity, and for an intermediate mode of inheritance, underscores the need for multicenter collaboration.

Adolescent↗
PubMed1996

Detection of anti-Borrelia burgdorferi antibody responses with the borreliacidal antibody test, indirect fluorescent-antibody assay performed by flow cytometry, and western immunoblotting.

Borreliacidal antibodies participate in the resolution of Lyme disease by clearing Borrelia burgdorferi sensu lato from the host. Detection of borreliacidal antibodies is also valuable for determination of the specific serodiagnosis of Lyme disease. We show in this work that antibody detected by the borreliacidal antibody test did not correlate with antibody detected by the indirect fluorescent-antibody assay or Western immunoblotting. Detection of borreliacidal antibody decreased with elimination of the spirochete from the host in the presence or absence of therapy. By contrast, the antibody responses detected by the indirect fluorescent-antibody assay or Western immunoblotting remained elevated or continued to expand, respectively. This suggests that the borreliacidal antibody test is a prognostic indicator for clearance of the spirochete. Additional investigations with humans are needed to confirm the prognostic potential of the borreliacidal antibody test.

Animals↗
PubMed1996

Macrophages exposed to Borrelia burgdorferi induce Lyme arthritis in hamsters.

The mechanism(s) by which Lyme arthritis is induced has not been elucidated. In this study, we showed that macrophages have a direct, effector role in the pathogenesis of Lyme arthritis. Severe destructive arthritis was induced in recipients of macrophages obtained from Borrelia burgdorferi-vaccinated and nonvaccinated hamsters exposed to Formalin-inactivated B. burgdorferi in vitro and then challenged with the Lyme spirochete. Swelling of the hind paws was detected within 8 h of infection, increased rapidly, and peaked at 21 h. This initial swelling decreased, and by day 4 only slight swelling was detected. Severe swelling of the hind paws was detected 8 days after infection and increased rapidly, with peak swelling occurring on day 11. Histopathologic examination affirmed that macrophages exposed to Formalin-inactivated spirochetes induced a severe destructive Lyme arthritis. The onset and severity of the severe destructive arthritis were dependent on the number of macrophages transferred. By contrast, macrophages not exposed to Formalin-inactivated B. burgdorferi failed to induce severe destructive arthritis in recipients after challenge with B. burgdorferi. Similarly, severe destructive arthritis was not detected in recipients of macrophages injected with spirochetal growth medium. Our results also showed that transferred macrophages could not protect hamsters from infection with B. burgdorferi, as spirochetes were readily recovered from their tissues when cultured. These findings demonstrate that macrophages exposed to B. burgdorferi are directly involved in the induction of Lyme arthritis.

Animals↗
PubMed1996

Molecular genetics of B-cell lymphomas: a review.

Recent developments in the past decade such as the advent of recombinant DNA technology, discovery of immunoglobulin gene rearrangements and recognition of the association of specific cytogenetic abnormalities with certain lymphoma subtypes have led to a better understanding of lymphoproliferative disorders. As the vast majority (80%) of non-Hodgkin's lymphomas are of the B-cell subtype, this is the focus of the article. By definition, tumours are clonal proliferations of a single, abnormal cell. Hence, B-lymphoid malignancy represents a monoclonal proliferation of B-lymphocytes. Immunophenotyping may be used to establish clonality for B-cell proliferations but may fail in some cases where surface antigens are not expressed or if the malignant clone is obscured by reactive lymphoid cells. Molecular methods are far more sensitive and do not require gene expression for detection, hence they are increasingly used for clonality assessment. Either Southern blot analysis or polymerase chain reaction can be used for this purpose. These techniques can also be used to detect specific cytogenetic abnormalities associated with certain lymphomas such as the bcl-2 gene rearrangement and follicular lymphoma. This is useful in the subtyping of lymphomas in cases where morphologic diagnosis is uncertain. Thus, with growing awareness and availability of molecular DNA analysis, these techniques are increasingly employed for the diagnosis of lymphomas as well as for the detection of minimal residual disease.

Blotting, Southern↗
PubMed1996

Mania following left hemisphere injury.

A case of mania following closed head injury to the left hemisphere is reported. The patient presented with a self-limiting manic episode that recovered without treatment. It is postulated that the head injury is the causative factor in this case. This was supported by laboratory results as well as psychological investigations. It is believed that non-dominant right hemisphere injury is related to the development of mania. However, a search of the literature revealed five other cases of mania following left hemispheric injury. Although the mechanisms implicated in the pathogenesis of secondary mania have not been established, this case adds to the growing evidence that head injury may be directly causative in affective psychoses. Therefore, it is premature to conclude that mania is a pathology of the non-dominant right hemisphere.

Accidents, Traffic↗
PubMed1995

Evidence for a genetic association between alleles of monoamine oxidase A gene and bipolar affective disorder.

We present evidence of a genetic association between bipolar disorder and alleles at 3 monoamine oxidase A (MAOA) markers, but not with alleles of a monoamine oxidase B (MAOB) polymorphism. The 3 MAOA markers, including one associated with low MAOA activity, show strong allelic association with each other but surprisingly not with MAOB. Our results are significant only for females, though the number of males in our sample is too small to draw any definite conclusions. Our data is consistent with recent reports of reduced MAOA activity in patients with abnormal behavioral phenotypes. The strength of the association is weak, but significant, which suggests that alleles at the MAOA locus contribute to susceptibility to bipolar disorder rather than being a major determinant.

Alleles↗
PubMed1995

Linkage studies on chromosome 22 in familial schizophrenia.

As part of a systematic search for a major genetic locus for schizophrenia we have examined chromosome 22 using 14 highly polymorphic markers in 23 disease pedigrees. The markers were distributed at an average distance of 6.6 cM, covering 70-80% of the chromosome. We analyzed the data by the lod score method using five plausible genetic models ranging from dominant to recessive, after testing the power of our sample under the same genetic parameters. The most positive lod score found was 1.51 under a recessive model for the marker D22S278, which is insufficient to conclude linkage. However, an excess of shared alleles in affected siblings (P < .01) was found for both D22S278 and D22S283. For D22S278, the A statistic was equal to the lod score (1.51) and therefore did not provide additional evidence for linkage allowing for heterogeneity, but the Liang statistic was more significant (P = .002). Our results suggest the possibility that the region around D22S278 and D22S283 contains a gene which contributes to the aetiology of schizophrenia.

Alleles↗
PubMed1995

Detection of bcl-1 gene rearrangement and B-cell clonality in mantle cell lymphoma using formalin-fixed, paraffin-embedded tissues.

Mantle cell lymphoma (MCL) has recently emerged as a distinct clinicopathologic entity with characteristic molecular genetic features. Specifically, MCL are clonal B-cell neoplasms and often harbor bcl-1 gene rearrangements. Although this genetic profile is well documented, scant or no data are available on the molecular assessment of MCL using formalin-fixed, paraffin-embedded tissue as a sample source. The polymerase chain reaction (PCR) was employed to study bcl-1 and immunoglobulin heavy chain (IgH) gene rearrangements (B-cell clonality) using formalin-fixed tissue from 12 cases of MCL. In addition, 12 cases of low grade B-cell lymphoma and 5 cases of reactive lymphocytic hyperplasia were studied as comparison controls. A hemi-nested PCR assay was developed to identify major translocation cluster (MTC) bcl-1 gene rearrangements, whereas IgH gene rearrangements were evaluated by both a single-step and hemi-nested approach. Bcl-1 gene rearrangements were amplified in 4 of 12 (33%) MCL, but in none of the controls. With the hemi-nested approach, B-cell monoclonality was demonstrated in 11 of 12 (92%) MCL; 6 of 6 (100%) small lymphocytic lymphomas; 1 of 2 marginal zone lymphomas; 1 of 4 follicular lymphomas; and 0 of 5 reactive lymphocytic hyperplasias. When one-step PCR was used for B-cell clonality assessment, the overall detection rate was lower, specifically: 8 of 12 (67%) MCL; 4 of 6 (67%) small lymphocytic lymphomas; 1 of 2 marginal zone lymphomas; 0 of 4 follicular lymphomas; and 0 of 5 reactive lymphocytic hyperplasias were identified as monoclonal. We have demonstrated that MTC bcl-1 gene rearrangements can be amplified from formalin-fixed tissue. In addition, monoclonal B-cell populations from MCL are better amplified with a hemi-nested approach rather than a single-step PCR assay. With specialized nucleic acid isolation techniques and appropriate PCR protocol design, formalin-fixed, paraffin-embedded tissue is an adequate source of DNA for assessing MTC bcl-1 and IgH gene rearrangements.

B-Lymphocytes↗
PubMed1995

Involvement of CD4+ T lymphocytes in induction of severe destructive Lyme arthritis in inbred LSH hamsters.

We determined that Borrelia burgdorferi-specific CD4+ T lymphocytes are responsible for the development of severe destructive Lyme arthritis and affect the production of borreliacidal antibody. Severe destructive Lyme arthritis was readily evoked in immunocompetent inbred LSH hamsters vaccinated with a whole-cell preparation of Formalin-inactivated B. burgdorferi sensu stricto isolate C-1-11 in adjuvant when challenged with B. burgdorferi sensu stricto isolate 297. When vaccinated hamsters were depleted of CD4+ T lymphocytes by the administration of monoclonal antibody GK1.5 and challenged, they failed to develop severe destructive arthritis. Similarly, nonvaccinated hamsters with or without the depletion of CD4+ T lymphocytes failed to develop severe destructive arthritis. In addition, depleting CD4+ T lymphocytes impaired the development of borreliacidal antibody in vaccinated and nonvaccinated hamsters challenged with the Lyme borreliosis spirochete. These findings show that CD4+ T lymphocytes are important for the recognition of arthritogenic and protective antigens of B. burgdorferi sensu lato isolates. Additional studies are needed to define the mechanisms responsible for the development of severe destructive Lyme arthritis and the production of borreliacidal antibody.

Animals↗
PubMed1995

Borrelia burgdorferi-specific T lymphocytes induce severe destructive Lyme arthritis.

This is the first documentation that Borrelia burgdorferi-specific T lymphocytes are involved in the pathogenesis of Lyme arthritis. We present direct evidence that T lymphocytes obtained from inbred LSH hamsters vaccinated with a whole-cell preparation of Formalin-inactivated B. burgdorferi sensu stricto isolate C-1-11 in adjuvant conferred on naive recipient hamsters the ability to develop severe destructive arthritis when challenged with B. burgdorferi sensu stricto isolates C-1-11 and 297. By contrast, recipients infused with normal T lymphocytes and challenged with B. burgdorferi sensu stricto isolates C-1-11 and 297 failed to develop severe destructive arthritis. The T lymphocytes transferred were obtained from the lymph nodes of vaccinated and nonvaccinated hamsters by depleting B lymphocytes by using monoclonal antibody 14-4-4s (< 1% B lymphocytes by flow cytometric analysis). The enriched T lymphocytes showed enhanced proliferation to stimulation with concanavalin A and failed to respond to lipopolysaccharide. Moreover, only the enriched T lymphocytes from vaccinated hamsters proliferated on exposure to a whole-cell preparation of B. burgdorferi sensu stricto isolate C-1-11 in the presence of mitomycin-treated syngeneic antigen-presenting cells. These results demonstrate that B. burgdorferi-specific T lymphocytes primed by vaccination with a whole-cell preparation of inactivated B. burgdorferi sensu stricto isolate C-1-11 in adjuvant are involved in the development of severe destructive arthritis. Additional experiments are needed to define the precise mechanism(s) responsible for the development of Lyme arthritis.

Animals↗