Displaying publications 1 - 20 of 68 in total

  1. Ong HC
    PMID: 1221499
    This study presents clinical observations in pregnancy made on aborigines of the deep jungle and "outside" populations. Migration out of the jungle results in lowered nutritional status as a result of low socio-economic status in the "outside" aborigine. This, together with food habits, increased family size and higher incidence of helminthic infestations, results in lower mean values of Hb, PVC and MCHC and a higher prevalence of anaemia in pregnancy in the migrant aborigine. A higher population density in the "outside" population resulting in frequent intermingling and increased chances of cross-contamination probably explains the increased vaginal bacterial growth in the "outside" Aborigine women. A higher prevalence of vaginal candidiasis in the "outside" aborigine woman is probably related to exposure to oral contraceptives and broad-spectrum antibiotics. On the other hand, better medical and obstetrical services become more readily available to the "outside" aborigine and this results in a favourable influence on perinatal health.
  2. Ong HC
    Acta Haematol., 1974;52(4):220-2.
    PMID: 4217527 DOI: 10.1159/000208244
    Haemoglobin E complicates 22.2°/o of pregnancy in Malaysian aborigines, the prevalence of variants associated with pregnancy being, 15.8% with Hb E trait abnormality, 3.9% with Hb E homozygous disease, and 2.5% with Hb E thalassaemia disease. Minor haematological abnormalities occur with the trait and homozygous conditions, though a more unfavourable response is expected with Hb E thalassaemia. Haemolysis is not a prominent feature and it is suggested that factors other than the haemoglobinopathic state
    probably accounts for any unfavourable response in pregnancy.
    Key Words: Haemoglobin E; Haemoglobinopathies; Haemolytic anaemias; Hb E thalassaemia; Malaysia; Pregnancy
    Study site: Hospital Orang Asli, Gombak, Selangor, Malaysia
  3. Ong HC, Alih E
    PLoS One, 2015;10(4):e0125835.
    PMID: 25923739 DOI: 10.1371/journal.pone.0125835
    The tendency for experimental and industrial variables to include a certain proportion of outliers has become a rule rather than an exception. These clusters of outliers, if left undetected, have the capability to distort the mean and the covariance matrix of the Hotelling's T2 multivariate control charts constructed to monitor individual quality characteristics. The effect of this distortion is that the control chart constructed from it becomes unreliable as it exhibits masking and swamping, a phenomenon in which an out-of-control process is erroneously declared as an in-control process or an in-control process is erroneously declared as out-of-control process. To handle these problems, this article proposes a control chart that is based on cluster-regression adjustment for retrospective monitoring of individual quality characteristics in a multivariate setting. The performance of the proposed method is investigated through Monte Carlo simulation experiments and historical datasets. Results obtained indicate that the proposed method is an improvement over the state-of-art methods in terms of outlier detection as well as keeping masking and swamping rate under control.
  4. Ong HC, Chelvam P
    Med J Malaysia, 1975 Jun;29(4):299-301.
    PMID: 1196178
  5. Ong HC, Soo KL
    Med J Malaysia, 2006 Dec;61(5):616-20.
    PMID: 17623964 MyJurnal
    It has been almost two decades ago since the first AIDS case was reported in Malaysia. It has also been approximately eight years ago when the method of backcalculation was used to estimate the past HIV infection rate from the AIDS incidence data and an estimate of the incubation period distribution. This method is used because it makes use of the Malaysian AIDS incidence which is fairly reliable and reflects the trend of the epidemic as compared to the HIV infection rate recorded. The latest results generated show a slowdown in the increase of the number of estimated infected HIV+ cases in the late 1990s and this trend is supported by a slowdown in the increase of the number of AIDS cases recorded.
  6. Ong HC, Chan WF
    Singapore Med J, 1977 Jun;18(2):100-4.
    PMID: 929220
    Benign cystic teratoma of the ovary has a varied incidence, varying from 30 to 50 per cent of all benign ovarian tumours. This tumour tends to occur in the reproductive age group (20 to 40 years), and the majority of patients are married with children. About 40 per cent of patients are symptomless. Of those with symptoms, abdominal pain and mass are the commonest. Torsion is the most frequent complication encountered, and the presence of acute pain should make one suspect this complication. The tumour is bilateral in 10 to 20 per cent of patients. This high bilateral occurrence places a responsibility on the gynaecologist to inspect the opposite ovary in all cases of unilateral dermoid cyst of the ovary at the time of laparotomy. Germ·layer derivatives are predominantly ectodermal in origin, although both mesodermal and entodermal derivatives occur frequently.
  7. Ong HC, Teo SP
    Med J Malaysia, 1976 Sep;31(1):42-5.
    PMID: 1023012
  8. Ong HC, Chan WF
    Cancer, 1978 Apr;41(4):1538-42.
    PMID: 639009
    A study of 207 benign ovarian tumors seen at the University Hospital, Kuala Lumpur between 1968 and 1975 was made to evaluate the clinical features that might be useful in the preoperative differentiation of mucinous cystadenoma, serous cystadenoma, and cystic teratoma of the ovary. This study indicated that the pertinent information included the mean age of the patient, the marital and menstrual status, and the estimated tumor size. The racial background was an additional factor in serous cystadenoma. Features like parity, the location of the tumor, and ABO blood group pattern were of no value in the preoperative differentiation.
  9. Ong HC, Quah SH, Low HC
    Med J Malaysia, 1998 Dec;53(4):385-91.
    PMID: 10971982
    The method of backcalculation estimates past HIV infection rates from available AIDS incidence data and an estimate of the incubation period. The method is used on the Malaysian data to model the AIDS epidemic because it makes use of the Malaysian AIDS incidence data which is fairly reliable and is more reflective of the trend of the epidemic as compared to the HIV infection rate recorded. An application is made on the monthly AIDS incidence data in Malaysia from January 1995 until August 1996 released by the Ministry of Health, Malaysia using the backcalculation program from Bacchetti et al and the incubation period distribution from Brookmeyer to generate the current HIV infection rate for Malaysia (until August 1996).
  10. Ong HC, Chan WF, Sinnathuray TA
    Med J Malaysia, 1978 Mar;32(3):217-9.
    PMID: 683046
  11. Chong HL, Ong HC, Ang LT
    Med J Malaysia, 1974 Sep;29(1):44-53.
    PMID: 4282630
  12. Ong HC, White JC, Sinnathuray TA
    Acta Haematol., 1977;58(4):229-33.
    PMID: 410224 DOI: 10.1159/000207832
    A case of haemoglobin H (HbH) disease associated with pregnancy is presented and discussed in the light of reports in the literature. The variable symptomatology is commented upon, although mild to moderate chronic haemolytic anaemia seems to be a constant feature. The roles of folic acid supplements and of splenectomy; the avoidance of oxidant drugs, and the mode of inheritance in HbH disease are briefly commented upon. Available reports indicate that HbH disease probably has no adverse effect on pregnancy. However, the association of the two conditions is uncommon, and reports are too few, therefore, to allow definite conclusions on the outcome in all instances.
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