Biomedical subjects
H W Ng
Publications and source records attributed to H W Ng.
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)
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.
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.
A study of the Lewis blood group system in the Singapore population.
The purpose of this retrospective study is to delineate: a) The ethnic group specific distribution patterns of the various Lewis phenotypes in our population in Singapore. b) The occurrence rates of the various anti-Lewis antibodies in our population. The approximate frequencies of the Lewis A-B-, Lewis A-B+ and Lewis A + B- phenotypes in the blood-donor population were estimated to be about 10%, 48% and 42% respectively. It was evident that frequency of the Lewis A-B- phenotype was highest among the Malays, being almost 3 times more frequent than it was among the Chinese (P less than 0.01). The anti-Lewis antibodies were noted to be the commonest irregular antibodies seen in our blood donor population, with an occurrence rate of about 127 per 100,000. Likewise, from 1982 to 1987, the anti-Lewis antibodies were also noted to be the most frequently encountered antibodies in our patient population, accounting for nearly 60% of all cases. Although the Malays comprised only about 15% of the Singaporean population, they accounted for as much as 42.9% of all patients with anti-Lewis antibodies. Similarly, out of all 76 blood donors in 1987 with anti-Lewis antibodies, 50% were found to be Malays although they comprised only 14.28% of the donor population. It was also interesting to note that a sizeable proportion of all patients with anti-Lewis antibodies were pregnant women with or without obstetric complications.
A study of the P blood group system in the Singaporean population.
The P blood-group system was discovered by Landsteiner and Levine in 1927. This study delineates: a) The ethnic group specific distribution patterns of the P1 blood group antigen in the population of Singapore. b) The occurrence rate of the anti-P1 antibody in the same population. In the blood donor population, the estimated incidence of the P1-negative phenotype was calculated to be 75%. Though the percentage of P1-negative individuals among the Chinese did not differ significantly from that for the Malays, it was significantly higher than that for the Indians (P less than 0.01). The weighted average incidence of anti-P1 in the blood-donor population over the period 1982-1987 was calculated to be 9.14 per 100,000. For the patients, the average incidence of the anti-P1 antibody was calculated to be about 13.9 per 100,000 patients. The Malays were noted to have the highest incidence of anti-P1 antibody despite the occurrence of a higher proportion of P1-negatives among the Chinese.
Near fatal drug interactions with methotrexate given for psoriasis.
Explore the source record for details and available documents.
Liver disease in blood donors with raised transaminases.
1000 consecutive blood donors had their liver functions studied. 110 donors (11%) were found to have raised ALT of more than twice normal levels. 29 donors had liver biopsies done. Histologically 23 had fatty change, 5 had chronic persistent hepatitis and 1 had liver cirrhosis. Fourteen out of the 23 donors with fatty change also had hypercholesterolemia and hypertriglyceridemia. Viral serology of the 110 donors showed that 3 donors were HBsAg positive, 5 donors were Anti-HAV (IgM) positive and 20 donors were Anti-HBc (IgM) positive. Majority of donors with raised ALT had fatty liver on biopsy with only 6 donors having significant findings of chronic persistent hepatitis and cirrhosis. Serologically, most of the donors (74.5%) with raised ALT had no markers of Hepatitis A, Hepatitis B, CMV or EBV. An interesting finding is the high incidence (18%) of positive, Anti HBc (IgM) in donors with raised ALT.
Patterns of infection in oncology patients in Singapore.
Explore the source record for details and available documents.
Immunological typing of acute lymphoblastic leukaemia patients in Singapore--a preliminary experience.
Six new patients with acute lymphoblastic leukaemia (ALL) have been studied with a battery of cell surface marker assays. These included T cell enumeration, B cell enumeration, monoclonal antibody studies for T cell subsets, (T helper cells, T suppressor cells and mature peripheral total T cells), HLA--DR (Ia-like antigens) and common ALL antigen. Three patients were found to have common ALL, 2 had null cell ALL and one had T cell ALL. Cytochemical studies on these 6 patients demonstrated a positive correlation between E rosette positivity and focal paranuclear staining with acid phosphatase. There appeared to be no correlation between FAB morphology and immunological subtype in the 6 patients studied.
Liver dysfunction in haemophilia A, B and other hereditary haemorrhagic disorders.
Seventy patients with Haemophilia A, B, von Willebrand's disease and Factor V deficiency had their liver functions studied. Twenty-five patients (36%) were found to have significant "transaminitis" (elevated SGPT/SGOT). Nine patients (13%) had positive Hepatitis B surface antigen (HBsAg). The incidence of Hepatitis B surface antibody (anti-HBs) in the study group was 74%. All patients were asymptomatic at the time of study. This asymptomatic liver dysfunction will require close monitoring for clinical significance.
An analysis of blood usage in elective surgery.
Pre-operative blood requests are often greatly in excess of the number of units of blood actually transfused during elective surgical procedures. Such practices are costly in terms of laboratory manpower and leads to unnecessary wastage of blood due to outdating. Developing guidelines for the number of blood units to cross-match preoperatively for surgical procedures optimises the use of blood. This study reports on blood ordering patterns and offers guidelines on the maximum number of units of blood to order for some of the commoner surgical procedures. The use of a Type and Screen procedure is recommended for those operations where blood is regularly ordered but rarely used. Operative procedures listed under the Surgical Tables 1 and 2 and the Minor Surgical Procedure Table, Ministry of Health, Singapore, fall into this group.
Malignant histiocytosis--a clinicopathologic study of 5 cases.
The clinico-pathological features of 5 patients with malignant histiocytosis aged 18 years to 73 years seen over a three year period from 1980 to 1983 at the Department of Haematology Singapore General Hospital were studied. Haematological, cytological and histopathological findings of the disease are described. Diagnosis of malignant histiocytosis was established from biopsies of bone marrow, liver, spleen or lymph nodes. Three out of the 5 patients died rapidly after diagnosis despite cytotoxic chemotherapy. One patient was lost to follow up while another is alive surviving so far for 3 months since diagnosis. The differential diagnosis of malignant histiocytosis is also discussed.
Chronic myeloid leukaemia in Singapore: a case study of 56 patients.
A case study was made on 56 patients with chronic myeloid leukaemia in Singapore. The most common clinical presentations were abdominal discomfort with swelling and hepatosplenomegaly. The mean haemoglobin, white cell count, and platelet count at presentation were 9.23 g/dl, 217.9 X 10(9)/1 and 418 X 10(9)/1 respectively. Twenty-three of the 56 patients had gone into blast transformation at the time of analysis. The median duration of the chronic phase from the time of diagnosis to the time of blast transformation was 23 months. The median duration of survival after blast transformation was 3 months. The median duration of survival for all patients was 23 months. Busulphan remains the drug of choice for the chronic phase of chronic myeloid leukaemia.
A case of systemic lupus erythematosus with sideroblastic anaemia terminating in erythroleukaemia.
A case of systemic lupus erythematosus is described in which for 10 years the only significant findings were erythema multiforme and vasculitis. Gross hepatosplenomegaly with persistent pancytopenia developed, and bone marrow examination revealed the presence of sideroblasts. The patient's condition deteriorated, and subsequently she developed a severe bleeding tendency, terminating in erythroleukaemia.
One year review of the blood cell separator programme.
Using the Haemonetic Model 30 intermittent continuous flow centrifuge, 142 procedures, including 64 granulocytes and platelets, 68 platelet collection, 8 therapeutic leukapheresis and 2 plasmapheresis were performed. Granulocyte transfusions (mean collection 1.39 x 10(10) granulocytes) were given to 27 neutropenic patients for febrile episodes which were unresponsive to systemic antibiotics. Thirty-eight thrombocytopenic patients received a mean of 4.2 x 10(11) platelets per collection. Bleeding was controlled in most of the patients who received transfusion with a mean rise in platelet count of 30.6 x 10(9)/L. Therapeutic leukapheresis were performed on 3 patients with chronic leukaemias. A mean of 2.53 x 10(11) cells were collected per run with a mean fall of 58.2 x 10(9)/L in the patients' white blood cell count. Plasmapheresis was used to treat 1 patient with multiple myeloma. The authors' experience demonstrates that cell separator support is essential for patients with bone marrow depression and that the therapeutic leukapheresis is effective therapy for selected patients with chronic leukaemias. Plasmapheresis is effective in patients with hyperviscosity syndrome.