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Biomedical subjects

S K Cheong

Publications and source records attributed to S K Cheong.

At least 19 recordsLinked to original sources
PubMed2000

A prospective randomized study of Chop versus Chop plus alpha-2B interferon in patients with intermediate and high grade non-Hodgkin's lymphoma: the International Oncology Study Group NHL1 Study .

UNLABELLED: The addition of a brief alpha interferon regimen to each CHOP induction cycle, plus one year of alpha interferon thrice weekly maintenance therapy, has no early effect on response rates or survival in patients with Intermediate or High grade cell NHL. BACKGROUND: The CHOP (Cyclophosphamide, Adriamycin. Vincristine, Prednisone) regimen is the most widely used first-line therapy for patients with Intermediate or High Grade (IG/HG) non-Hodgkin's lymphoma (NHL). Alpha 2b interferon (INF) enhances response rates and improves survival in low-grade NHL. The International Oncology Study Group (IOSG) conducted a prospective randomized study comparing CHOP alone or combined with INF in patients with IG/HG-NHL. The primary study aim was to compare the objective response rates in these patient cohorts. PATIENTS AND METHODS: Patients with a confirmed diagnosis of measurable NHL of International Working Formulation (IWF) groups D to H histology were randomized to receive CHOP alone or CHOP with 5Mu INF s.c. for 5 days on days 22 to 26 of each 28 day cycle with INF 5 million units (Mu) given three times per week subcutaneously for 52 weeks in those patients who responded to CHOP plus INF. RESULTS: The overall response rates were equivalent in both groups: CHOP alone (214 patients) 81% (complete 55%, partial 26%); CHOP plus INF (221 patients) 80% (complete 54%, partial 26%). At 36 months, the actuarial survival rate was equivalent in both groups. CONCLUSIONS: There is no apparent early advantage in terms of response or survival conferred by adding the study INF regimen to CHOP therapy for patients with IG/HG-NHL.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2000

Successful pregnancy in a patient with familial sea-blue histiocyte syndrome.

A 27-year-old Indian woman at 23 weeks' gestation presented with decompensated liver cirrhosis, coagulopathy, restrictive lung disease with cor pulmonale and preeclampsia. She was diagnosed to have sea-blue histiocyte syndrome (SBHS) at the age of 13 years and was treated conservatively. There was worsening liver, respiratory and bone marrow function as the pregnancy progressed. She underwent a successful pregnancy despite her poor medical condition and advanced disease state. We described the first case of familial SBHS in a pregnant patient from Asia.

Adult↗
PubMed2000

BCR-ABL positive essential thrombocythaemia: a variant of chronic myelogerous leukaemia or a distinct clinical entity: a special case report.

A 37-year-old Malay man presented initially with the clinical picture of essential thrombocythaemia (ET) without the extreme leukocytosis, marked splenomegaly and low neutrophil alkaline phosphatase characteristic of chronic myelogenous leukaemia (CML). Bone marrow examination showed massive megakaryocytic hyperplasia; cytogenetic studies showed the presence of Philadelphia chromosome. The patient was treated with hydroxyurea that resulted in reduction in the platelet count. Seventeen months later, he presented with fever associated with tender massive splenomegaly. Bone marrow finding was consistent with chronic phase CML. The presence of a rearrangement involving the major breakpoint cluster region (M-bcr) on chromosome 22 was confirmed by reverse transcriptase-polymerase chain reaction. The clinical importance of finding the Philadelphia chromosome in patients who seem to have ET is in assessing prognosis. ET generally follows a chronic, indolent course. However, this patient who had Philadelphia chromosome underwent clinical transition to chronic phase CML17 months and blast crisis 29 months after presentation.

Adult↗
PubMed1999

Glucose-6-phosphate dehydrogenase (G6PD) variants in Malaysian Chinese.

We screened 38 G6PD-deficient male Chinese neonates for known G6PD mutations using established PCR-based techniques. We found 50.0% (19 of 38) were mutation 1376G>T, 34.2% (13 of 38) were mutation 1388G>A, 5.2% (2 of 38 ) were mutation 95A>G and 2.2% (1 of 38) was mutation 1024C>T. In 7% (3 of 38) of the cases the mutations remained uncharacterised. Sixty three percent (24 of 38) of the G6PD deficient neonates had neonatal jaundice with 28.9 % (11 of 38) developing moderate to severe hyperbilirubinemia. The group of neonates with 1388 mutation showed the highest incidence of moderate to severe hyperbilirubinemia requiring phototherapy and/or exchange transfusion respectively. Majority (70%) of the G6PD deficient neonates showed severe enzyme deficiency. However, there was no meaningful association between the level of enzyme activity and the severity of neonatal jaundice. In summary, four mutations account for more than 90% of the G6PD deficiency cases among the Chinese in Malaysia and the pattern of distribution of the molecular variants is similar to those found among the Chinese in Taiwan and southern mainland China. Our findings also suggest the possible association of nt 1388 mutation with severe neonatal jaundice.

Amino Acid Substitution↗
PubMed1999

Comparative analysis of three permeabilization methods for cytofluorometric evaluation of cytoplasmic myeloperoxidase.

A comparative study was conducted to evaluate three different permeabilization methods: FACS Permeabilizing Solution (FPerm), CytoFix/CytoPerm Kit (CFP) and Paraformaldehyde-Tween 20 (PFT) reagents, in cytoplasmic labeling of myeloperoxidase (MPO). Peripheral blood cells from 23 healthy subjects were fixed and permeabilized according to the proposed procedures, prior to direct immunofluorescence staining with CD14, CD45, IgG1, IgG2 and MPO monoclonal antibodies (McAb). Subsequent flow cytometric analysis was performed on FACSCalibur flow cytometer (Becton Dickinson, BD). As far as the antigenic expression of MPO in normal samples is concerned, FPerm and CFP demonstrated better cytoplasmic staining by inducing minor effects on light-scattering properties of the cell populations, whereas PFT-treated samples showed a diminished ability to distinguish the cell types. However, the simple and rapid FPerm method required an earlier processing of samples since the stored whole blood samples (for more than 8 hours) tended to show a significant decrease of fluorescence intensity. We also have demonstrated that P/N ratio possesses added value in evaluation of cell reactivity in immunophenotyping, based upon the apparent nonspecific cytoplasmic staining of MPO in the lymphocyte population.

Adult↗
PubMed1999

Quantitation of T lymphocyte subsets helps to distinguish dengue hemorrhagic fever from classic dengue fever during the acute febrile stage.

Activation of immunoregulatory T lymphocyte subsets has been observed in dengue viral infection, being more evident in dengue hemorrhagic fever (DHF) than in classical dengue fever (DF). There are, however, as yet no well-defined host markers to determine which patients with dengue viral infection will develop severe complications during the acute febrile stage of the disease. A study was performed to compare the cellular immune status in DHF, DF and non-dengue viral infections (NDF) in order to determine the value of these parameters in distinguishing DHF from classic DF and other viral infections during the acute febrile stage of the disease. This study involved 109 febrile patients admitted because of suspected DHF. Fifty patients were serologically confirmed cases of dengue infection, of which 25 had grade 1 or 2 DHF. There was a reduction in total T (CD3), CD4 and CD8 cells in DHF and demonstrated that a low level of CD3, CD4, CD8 and CD5 cells discriminated DHF from DF patients during the febrile stage of the illness. In contrast, B (CD19) cells and natural killer (NK) cells did not appear to be discriminatory in this study. Receiver operating characteristic (ROC) curve analysis showed that a combination of CD3 cell of < or = 45% and CD5 cell of < or = 55% was the best marker to identify DHF patients (sensitivity = 84% and specificity = 52% for CD3 cell of < or = 45%; sensitivity = 92% and specificity = 71% for CD5 cell of < or = 55%). CD4 cell of < or = 25% and CD8 cell < or = 30% were equally good in discriminating DHF from DF patients. On the other hand, the ROC curves indicated no clear difference between the immunoregulatory cell counts in DF from NDF Lymphopenia, atypical lymphocytosis and thrombocytopenia were significantly more evident in dengue compared to non-dengue infection but did not appear to be discriminatory among DHF and DF patients. The reduction in CD3, CD4, CD8, CD5 cells correlated with the degree of thrombocytopenia in DHF (p < 0.05) which suggests that these cells probably participate in a common pathogenetic mechanism.

Acute Disease↗
PubMed1999

Cold agglutinins in low-grade B-cell lymphoma.

The presence of serum cold agglutinin can be the initial presentation of lymphoproliferative diseases. Conditions with persistent cold agglutinins are a spectrum of diseases that vary from benign lymphoproliferation of the "autoimmune-like chronic cold agglutinin disease" to malignant lymphoma. We report a case of a 72-year-old woman who presented with severe anaemia, hepatosplenomegaly and episodes of peripheral haemagglutination precipitated by cold exposure. The haemoglobin was 5.6 g/dL with a cold agglutinin titer of 1:256 at 4 degrees C and 1:8 at room temperature (30 degrees C). The cold agglutinin showed anti-I specificity and kappa light chain restriction. Peripheral blood showed atypical lymphoid cells with a B-cell immunophenotype. Immunoglobulin gene rearrangement study by polymerase chain reaction (PCR) showed an amplified band at 100 bp, consistent with a clonal proliferation of B-lymphocytes. We believe that our patient had cold antibody haemolytic anaemia as the initial presentation of a low-grade non-Hodgkin's lymphoma. The association of cold antibody haemolytic anaemia with low-grade B-cell lymphoma is unusual.

Aged↗
PubMed1999

Positive direct antiglobulin test with Unasyn--a case report.

A 56-year-old Chinese lady with valvular heart disease and atrial fibrillation was referred to us from a private hospital for further management of autoimmune haemolytic anaemia. Physical examination and laboratory investigations did not support the diagnosis of haemolytic anaemia. However, direct antiglobulin test (DAT) was strongly positive with anti-IgG and negative with anti-C3d. There was also mild anaemia and reticulocytosis, which was attributable to persistent haematuria. The DAT became positive after commencing Unasyn and cessation was associated with decreasing reactivity of the positive DAT. We believe that the positive DAT in this patient was most likely due to the Unasyn therapy.

Ampicillin↗
PubMed1998

Flow cytometric analysis of intracellular myeloperoxidase distinguishes lymphocytes, monocytes and granulocytes.

A study was undertaken to evaluate the ability of flow cytometric analysis of intracellular myeloperoxidase (MPO) in differentiating populations of lymphocytes (L), monocytes (M) and granulocytes (G), by means of lysed whole blood method. Anticoagulated blood from 23 normal individuals was lysed with FACS lysing solution and permeabilized with FACS permeabilizing solution before subjected to direct immunofluorescence staining. The geometric means of the fluorescence intensity were measured using FACSCalibur flow cytometer (Becton Dickinson). Populations of L, M and G were gated based on their light scatter characteristics and expression of CD14 and CD45. Then, the fluorescence intensity of MPO expression was studied in these individual cell populations. The results showed that fluorescence intensity of MPO was the strongest in G and weakest in L, whereas M showed intermediate fluorescence intensity. Our findings reveal that discrimination of these three cell types is achievable based upon the sole expression of intracellular MPO.

Antigens, Surface↗
PubMed1998

Serum ferritin and lactate dehydrogenase in a case of hemophagocytic lymphohistiocytosis.

A 40-day-old baby girl presented with intermittent fever, lymphadenopathy, massive hepatosplenomegaly, progressive pancytopenia and features of disseminated intravascular coagulopathy. A bone marrow aspiration was performed and showed florid histiocytic proliferation with marked hemophagocytosis. Based on the diagnostic guideline for Hemophagocytic Lymphohistiocytosis proposed by the Familial Hemophagocytic Lymphohistiocytosis Study Group of Histiocyte Society, this patient has fulfilled most of the criteria. We have also found that serum ferritin and lactate dehydrogenase to be very high in this patient. It remains uncertain whether the disorder is reactive or neoplastic.

Bone Marrow Cells↗
PubMed1997

Usefulness of stable microbubble test of tracheal aspirate for the diagnosis of neonatal respiratory distress syndrome.

OBJECTIVES: To compare the overall accuracy of the stable microbubble test (SM test) with measurement of level of surfactant protein A (SP-A) of tracheal aspirate for the diagnosis of respiratory distress syndrome (RDS). METHODOLOGY: Tracheal aspirates were obtained from neonates on ventilatory support. The SM test was carried out on specimens of tracheal aspirate immediately after collection. Levels of SP-A in tracheal aspirates were determined by enzyme-linked immunosorbent assay (ELISA) method. The results of the SM test and SP-A level of the tracheal aspirates were compared against the clinical diagnosis of RDS based on clinical, radiological and bacteriological findings. RESULTS: Both the median microbubble counts (6 microbubbles/mm2, range = 0-90) and median SP-A levels (100 micrograms/L, range = 0-67447) of infants with RDS were significantly lower than those of infants with no obvious lung pathology (P < 0.0001), and pneumonia (P < 0.0001). The SM test of tracheal aspirates had higher overall accuracy for the diagnosis of RDS than measurement of SP-A levels (94.6% vs 82.4%). When the receiver operating characteristic (ROC) curves of both tests for RDS were compared, the area under the ROC curve of the SM test was larger (0.9689) than that of the SP-A method (0.8965). CONCLUSIONS: This study showed that the SM test of tracheal aspirate was a useful bedside diagnostic test for RDS. It could be carried out at any time after birth on infants requiring ventilatory support.

Cross-Sectional Studies↗