The style of processing scale: normative and reliability data.

Three student samples (ns=624, 653, and 566) yielded normative data for the Style of Processing scale. Analysis of subsamples found acceptable internal reliability (overall r=.78) and good test-retest reliability (overall r=.81, 6-mo. interval). The scale appears to have satisfactory reliability for assessing verbal-visual cognitive style, but further work is needed to test the scale's validity.

Autologous transfusion in obstetrics.

AIM OF STUDY: To assess the safety of blood collection for autologous transfusion in pregnant women and the effects of the procedure on the fetus. METHOD: Prospective study involving obstetric patients undergoing elective lower segment Caesarean section (LSCS) between 1993 and 1994 were recruited for autologous transfusion. Continuous cardiotocograph monitoring was carried out throughout the duration of the procedure and the fetal haemodynamics was studied before and after by doppler blood flow ultrasound. RESULTS: The results show that there was no fetal deceleration or increased uterine activity as monitored by cardiotocography. The mean pulsatility index (PI) for the umbilical artery before the procedure was 0.9560 and after was 0.0820 which is a significant difference (p value = 0.035). CONCLUSION: Autologous blood collection seems to be a safe procedure for both the mother and the fetus. However, autologous transfusion remains an unpopular choice amongst pregnant women.

Comparison of peripheral blood CD34+ concentration, colony-forming units granulocyte-macrophage and mononuclear cells in leukapheresed product for the prediction of peripheral blood CD34+ cell yield harvest.

The aim of this study was to evaluate reliability of parameters which may be used to guide peripheral stem cell harvests in cancer patients prior to myeloablative chemotherapy. Each leukapheresed product was analysed for CD34-positive (CD34+) cell count, mononuclear cell (MNC) count and the number of colony-forming units granulocyte-macrophage (CFU-GM). Each patient's peripheral blood (PB) taken before leukapheresis was analysed for CD34+ concentration. We evaluated whether the CD34+ yield from leukapheresis correlated with any of the three parameters. A total of 119 procedures were performed in 33 patients. The yield of CD34+ cells by leukapheresis correlated weakly but significantly with the peripheral blood CD34+ cell count (R = 0.4 P < 0.05), the MNC cells (R = 0.4, P < 0.05), and CFU-GM (R = 0.4, P < 0.05). When a PB CD34+ count of 50 x 10(6)/L was used as a cut-off value, the accuracy for prediction of adequate leukapheresis (> 1 x 10(6) CD34+ cells/kg) was 78%.

Racial differences in Helicobacter pylori seroprevalence in Singapore: correlation with differences in peptic ulcer frequency.

The aim of this study was to determine, first, whether racial differences exist in the seroprevalence of Helicobacter pylori infection in Singapore, and second, whether these differences correlate with racial differences in peptic ulcer frequency. A commercial serological test for immunoglobulin (Ig)G antibody to H. pylori which was 90% sensitive and 83% specific in our population was used to screen 403 adult blood donors of Chinese, Malay and Indian origin, aged between 15-60 years. Serum specimens from 84 paediatric patients admitted to the Paediatrics Department, National University of Singapore, with non-gastroenterological illnesses were also tested. In all three races, seroprevalence of H. pylori increased with age. Indians have the highest prevalence of infection followed by Chinese and Malays. Peptic ulcer prevalences are known to be highest in Chinese, followed by Indians and Malays. The Malays have the lowest prevalence of H. pylori and peptic ulcer among the three races in Singapore. Indians have a higher prevalence of H. pylori antibodies but a lower frequency of peptic ulcer than the Chinese. Racial differences in peptic ulcer frequency between Chinese and Indians are not explained by the prevalence of H. pylori infection; other environmental or genetic factors may be involved.

Gastrointestinal lymphoma--a review of 54 patients in Singapore.

Primary gastrointestinal (GI) lymphoma accounts for 2% to 5% of all GI malignancies. Primary therapy in uncomplicated GI lymphoma remains controversial. Fifty-four patients (male to female ratio of 4:3, median age 56 years) with GI lymphoma were studied to evaluate complications and results of therapy. The sites involved were the stomach (31), small bowel (12), large bowel (4), gallbladder (1) and multifocal (6). Distribution by stage and grade (Working Formulation or Kiel) were: IE-30%, IIE-43%, IIIE-6%, IV-20% and unknown-1%; low grade-33%, intermediate grade-59% and high grade-8%. Majority (54%) had diffuse large cell lymphoma. Twenty-three patients (43%) underwent primary resection of the tumour followed by chemotherapy in 14 or radiotherapy in 3. Seventeen patients (31%) had primary chemotherapy and 3 (6%) had primary radiotherapy. Of the 48 patients who underwent therapy, 52% had complete response. At the last follow-up (median 21 months), 25 patients were disease-free. Overall survival was 67% at two years. Treatment strategies employing surgery, radiotherapy and chemotherapy, alone or in combination, do not appear to influence outcome. Surgical resection plus chemotherapy appear to be effective in the control of local and distant disease.

A study of treponema pallidum haemagglutination positive blood donors in Singapore.

The Treponema Pallidum Haemagglutination (TPHA) test has been used for screening of syphilis among blood donors in Singapore since September 1992. Among the 79 500 donations that were screened between September 1992 and December 1993, 191 were tested positive (incidence rate of 0.24%). Seventy-two donors (37.7%) were evaluated at the Department of Sexually Transmitted Disease Control clinic. Seventy-nine percent of these donors had high risk sexual exposure and 33.3% had a history of sexually transmitted diseases. Eighty-three percent of the donors were diagnosed to have late latent syphilis, 9.7% were diagnosed to have a serological scar and the remaining had secondary syphilis, early latent syphilis and a false positive reaction. At least 65.3% of these donors would have been missed if the reagin test was used alone as the screening test. Thus, the TPHA test is a good marker for screening those who have high risk sexual behaviour and it is a more sensitive test than the reagin test for screening blood donors.

How sexually permissive are Singaporeans?

This paper presents data on two surveys done in 1989 and 1992 that indicated the attitudes of Singaporeans to sexuality. Both surveys revealed that Singaporeans have sexually conservative attitudes and those who have a lower education, are single, above the age of 40, are Malays/Muslims hold more conservative views.

Genetic polymorphism within HLA-A*02: significant allelic variation revealed in different populations.

HLA-A2 is present at high frequency in most populations, as identified by serological and biochemical means. The value of these methods is limited by their failure to discriminate between the products of the 14 known allelic HLA-A*02 variants. The great majority of genetic polymorphism which defines the allelic variants is found in exons 2 and 3 of the A*02 genes. These exons encode the alpha-1 and alpha-2 domains of the HLA Class I molecules, and variation within the genes may influence the peptide binding specificity of the gene products of each allele. Failure to accurately assign the allelic types has implications in transplantation, in interpretation of cellular assays and in the understanding of HLA disease associations. We have developed a method for determining the 14 known alleles of HLA-A*02 by use of ARMS-PCR to determine the degree of variation of HLA-A*02 alleles in 3 different population groups. Considerable variation was found in the relative frequencies of particular A*02 alleles between Caucasian, oriental and black individuals. Our results indicate the importance of ethnic origin in terms of the expected HLA-A*02 allelic profile, and emphasize the functional significance of allele specific subtyping of HLA-A*02.

A study of platelet alloantibody in multiply-transfused haematology patients.

This paper studies the prevalence of platelet antibody in multiply-transfused leukaemia and other transfusion-dependent non-leukaemic patients, using a solid phase red cell adherence (SPRCA) assay and a microlymphocytotoxicity (LCT) test. A positivity rate of 26% in the leukaemic patients and 72% in non-leukaemic patients was obtained with the SPRCA assay, compared to a higher positivity rate of 69% and 83% in the respective groups using the LCT test. Several explanations are proposed. The lower sensitivity of the SPRCA assay suggests that the LCT test may need to be run concurrently for higher diagnostic yield. This paper also compares the performance between an in-house SPRCA test method and the commercial Capture P test kit, and good concordance was shown in repeated occasions.

MACOP-B in advanced non-Hodgkin's lymphoma.

Between May 1986 and March 1991, 38 patients with previously untreated advanced intermediate and high-grade non-Hodgkin's lymphoma were treated with methotrexate, doxorubicin, cyclophosphamide, vincristine, prednisone, and bleomycin (MACOP-B): 73% of the patients had stages III and IV disease, 55% had "B" symptoms, and 55% had bulky disease (nodal masses > 10 cm). Histologic subtypes included diffuse large-cell and immunoblastic lymphoma. In 96% of patients clinical response was achieved (69% complete response and 27% partial response). Acturial disease-free survival and overall survival were 55% and 60%, respectively, at 2 years. Treatment-related mortality was 16%: 3 patients died from neutropenic sepsis and 3 (hepatitis B carriers) from fulminant hepatitis at the time of steroid withdrawal. The incidence of nonfatal neutropenic fever was 24% and mucocutaneous toxicity was common. The poorer overall results may be attributed to more advanced disease. Caution is advised in the use of MACOP-B among hepatitis B carriers.

Main causes of pre-donation deferral of prospective blood donors in the Singapore Blood Transfusion Service.

A retrospective study of the main causes of pre-donation deferral of prospective blood donors in the Singapore Blood Transfusion Service was carried out. Computerised records of all pre-donation deferrals from 1 January 1988 to 31 December 1991 were studied. A total of 278,401 pre-donation screening interviews were carried out during this period. Forty thousand one hundred and sixty-three or 14.4% of these transactions resulted in deferral of prospective blood donors either temporarily or permanently. Analysis of the deferrals showed that the top ten defined causes were: recent ingestion of medication; influenza; low haemoglobin level; a raised blood pressure; recent sexual exposure in high-risk activity; being underweight; Hepatitis B carrier status; recent history of measles, chickenpox or other infections; tattoos, ear-piercing or acupuncture in the preceding six months; and presenting for a subsequent donation too soon. To protect blood donors and recipients, stringent donor screening criteria are necessary. Modifying physical criteria could lower deferral rates but must be preceded by studies to ensure that donors do not suffer ill-effects. Increased public education on common causes of donor deferral may also lower deferral rates by allowing prospective donors to "pre-screen" themselves. However, one-to-one medical screening and appropriate counselling are still the best means for accepting or deferring blood donors in the Singapore setting.

Altered immunity in haemophiliacs treated exclusively with cryoprecipitate.

Sixty-five patients with haemophilia A from Singapore General Hospital, treated within the last 15 years exclusively with cryoprecipitate, were studied for the effect of the total number of exposures to random blood donors on their immune system. These haemophiliacs were aged 4 to 71 years (median 24 years) and were all apparently healthy with no clinical evidence of viral infection. None of them was a homosexual or intravenous drug user. All of them tested negative for human immuno-deficiency virus antibody and hepatitis B surface antigen. Analysis of the T-lymphocyte subset population showed 20 out of 65 haemophiliacs or 30.8% had reversal of T4/T8 ratio, ie. less than 1.00. There was no significant difference in the mean age of the 20 patients with abnormal T4/T8 ratios compared with the 45 with normal T4/T8 ratios. The mean age of the former group was 23 and the latter was 25. The group with reversal of T4/T8 ratio had exposure to 827.4 +/- 137.3 (mean +/- SEM) random blood donors, which is significantly higher than 402.5 +/- 64.1 in the group with normal T4/T8 ratio (p < 0.05). The reversal of T4/T8 ratio is predominantly due to the suppression of absolute T4 cell counts, with slightly raised absolute T8 cell counts. This abnormality may be transient or permanent. Interestingly, all the six out of 65 haemophiliacs with factor VIII inhibitor did not show any reversal of T4/T8 ratio in this study.

A survey of sexual behaviour of Singaporeans.

In order to plan education programmes against sexually transmitted diseases (STDs) and HIV infection, a population-based survey on partner relations was conducted on 2,115 Singaporean men and women aged between 15 and 49 years. Of the 605 (60.1%) sexually experienced men and 647 (58.3%) sexually experienced women, 510 (84.3%) men and 644 (99.5%) women were married. Of the marrieds, 465 (76.9%) men and 638 (98.6%) women had their first sexual encounter with the person who was or later became their spouse. Of the sexually experienced men, 97 (16%) engaged in casual sex in the previous year, of which 76 (78.4%) were encounters with commercial sex workers. Of these encounters 55 (72.4%) were unprotected or partially protected by condoms. A history of casual sex in the previous four weeks was given by 18 men, of whom 14 (77.8%) were married. Nine (64.3%) of these married men had sex concurrently with both their wives and commercial workers. Persons at high risk were those who started sexual activity early, unmarried, sexually active men with no or low education, and persons who travelled. Of the sexually experienced respondents, 1,242 (99.2%) had heard about condoms, and 431 (34.4%) were currently using them as contraceptive devices. Attitudes towards condoms and willingness to use them to prevent STDs and HIV infection were favourable. Men were more permissive in their attitudes towards sex. The level of permissiveness in men and women was not corroborated by their reported behaviour, an indication of either under-reporting and/or a disparity between attitude and practice.

Fulminant hepatic failure in non-Hodgkin lymphoma patients treated with chemotherapy.

Chemotherapy is the mainstay of therapy for patients with non-Hodgkin lymphoma. Among side-effects associated with the use of chemotherapy, immunosuppression is one which can be potentially fatal. In hepatitis B carriers, immunosuppression permits widespread infection of the hepatocytes and its subsequent withdrawal causes an "immunological rebound" leading to massive necrosis of hepatocytes. 4 patients who died of fulminant hepatitis following chemotherapy are reported. These were patients with positive hepatitis B serology. Caution is advised when treating non-Hodgkin lymphoma in patients from hepatitis B endemic regions.

Individualised treatment of seven cases of acquired factor VIII inhibitors.

Seven non-haemophilic patients with acquired Factor VIII inhibitors, admitted to Singapore General Hospital from 1986 to 1990, were studied to analyse their characteristic clinical features and therapeutic outcome. They all had low Factor VIIIC activities, ranged from 0 to 7% and their Factor VIII inhibitors ranged from 1.5 to 128 Bethesda units. All were Chinese aged 30 to 66 years, median 49 years. Six were females, with only one male. Five had associated autoimmune diseases and two had no apparent underlying disorder. One out of seven patients died despite treatment. Therapeutic approach is largely individualised. It may be life-threatening and needs prompt and adequate treatment.

Apparent change of Rhesus blood group typing in a case of ulcerative colitis.

An interesting case of ulcerative colitis with an apparent change of Rhesus blood group typing is described. To our knowledge, this has not been reported before. We postulate that during the initial active phase of ulcerative colitis, an unknown D-like antigen, possibly bacterial in origin, could temporarily give rise to a Rhesus D-positive blood group typing in a patient with Rhesus D-negative blood type. Interestingly, with continuous immunosuppressive therapy for ulcerative colitis, the patient did not develop anti-D antibodies despite multiple transfusions with D-positive blood.

A preliminary report on ABO incompatible bone marrow transplant.

Between September 1985 and June 1990, five patients with major and six patients with minor ABO blood group incompatibility between donor and recipient underwent allogeneic bone marrow transplantation (BMT) in the Singapore General Hospital. The period to engraftment, rate of recovery of peripheral blood leukocytes, granulocytes, and platelets and the incidence of graft versus host disease (GVHD) was similar to that observed following ABO blood group compatible marrow transplant. Erythroid development and reticulocytosis were, however, significantly delayed in patients receiving major ABO incompatible marrow transplant.

A psychosocial study of high risk subjects for AIDS.

A psychosocial study of 5 high risk groups for AIDS (50 homosexuals, 50 drug addicts, 23 male to female transsexuals, 45 male patients at a sexually transmitted disease clinic, and 43 female prostitutes) and 5 matched control groups showed that the majority of the subjects were mostly single, with a secondary level of education and lived with family members. Although all had a high risk of AIDS, condom use was not prevalent. The subjects were less knowledgeable about AIDS than controls, were more anxious about getting AIDS and had a more hopeless and pessimistic outlook to life; however they appeared to be as altruistic and responsible as the controls.

Yields of fibronectin by heparin-cold-precipitation from plasma.

Fibronectin prepared by heparin-cold-precipitation from 10 packs each of 24-hour plasma, stored plasma and 6-hour frozen plasma was assayed by electroimmunodiffusion. Its yield obtained from 24-hour plasma was significantly higher than that from stored plasma (p less than 0.01) indicating a decline with storage. Freezing of plasma within 6 hours retards degradation of fibronectin. Therefore, 24-hour plasma or 6-hour frozen plasma should be used to prepare fibronectin in order to achieve a better yield.

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.