Displaying publications 81 - 100 of 179 in total

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  1. Cheah PL, Looi LM, Ng MH, Sivanesaratnam V
    J Clin Pathol, 2002 Jan;55(1):22-6.
    PMID: 11825919
    AIM: Telomerase activity was studied in invasive uterine cervical carcinoma to assess whether it was activated during cervical malignant transformation and to look for a possible association with human papillomavirus (HPV) infection in a set of Malaysian patients.

    METHODS: Histologically confirmed invasive cervical carcinoma and benign cervices were assayed for telomerase activity using a commercial telomerase polymerase chain reaction (PCR) enzyme linked immunosorbent assay kit. The same cases were subjected to PCR detection of HPV using type specific (HPV types 6b, 11, 16, and 18) followed by L1 open reading frame (ORF) consensus primers.

    RESULTS: HPV was detected in 18 (13 HPV-16, one HPV-6b, four only L1 ORF) of 20 invasive cervical carcinoma and one (only L1 ORF) of 19 benign cervices. Raised telomerase activity (A(450 nm) > 0.215) was detected in 11 cervical carcinomas, with A(450 nm) ranging between 0.238 and 21.790 (mean, 3.952) in positive squamous carcinomas, whereas A(450 nm) was only 0.222 in the one positive adenosquamous carcinoma. Five of 11 cervical carcinomas in stage I, three of six in stage II, both in stage III, and the only case in stage IV showed telomerase activation. Increased telomerase activity was noted in five of the 12 lymph node negative, five of the seven lymph node status unknown cases, and the one case with presumed lymph node metastasis. Ten of 18 HPV positive and one of two HPV negative cervical carcinomas showed telomerase upregulation.

    CONCLUSIONS: Telomerase is activated in invasive cervical carcinoma. Although larger studies are needed, there seems to be no clear association between telomerase upregulation and HPV status, although there is a suggestion of increased telomerase activity in squamous carcinomas and late stage disease.

  2. Cheah PL, Looi LM
    Pathology, 2002 Aug;34(4):326-31.
    PMID: 12190289
    AIMS: The pattern of p53 expression was studied in pre-invasive and invasive cervical carcinoma in an attempt to clarify its role in cervical carcinogenesis.

    METHODS: A total of 234 invasive cervical carcinomas (152 squamous cell carcinomas, 61 adenocarcinomas and 21 adenosquamous carcinomas) and 16 cervical intraepithelial neoplasia (CIN) I, six CIN II and 25 CIN III were immunohistochemically studied for p53.

    RESULTS: p53 was detected more frequently in CIN and invasive carcinoma (100% of CIN I, 74.2% CIN II + III and 70.1% invasive carcinoma) compared with benign cervices (P< 0.001); however, only three squamous cell carcinomas, 11 adenocarcinomas and two adenosquamous carcinomas exhibited p53 expression in >75% of tumour nuclei. Six of the 11 adenocarcinomas and both adenosquamous carcinomas were poorly differentiated compared with one of the three squamous carcinomas. p53 immunoreactive cells were randomly distributed in invasive carcinoma, confined to the lower third of the epithelium in CIN I, reached the middle third in 20% of CIN II and upper third in 16.6% of CIN III.

    CONCLUSIONS: Assuming that p53 immunoreactivity indicates gene mutation when the majority (> 75%) of neoplastic cells express p53, p53 mutations would seem uncommon in cervical carcinogenesis. Nonetheless, glandular malignancies, in particular poorly differentiated variants, may show a higher frequency of mutation. p53 was detected more frequently in CIN I compared with CIN II/III and invasive carcinoma which may be due to p53 protein degradation following interaction with high risk human papillomavirus E6 protein in CIN II/III and invasive carcinoma.

  3. Munchar MJ, Sharifah NA, Jamal R, Looi LM
    Pathology, 2003 Apr;35(2):125-9.
    PMID: 12745459
    CD44 is a cell adhesion molecule that plays an important role in the cascade of metastasis and progression of human malignant tumours. A large family of variants or isoforms, generated by alternative splicing of a single gene, has been reported to be involved in the malignant process by conferring metastatic potential to non-metastatic cells. The objective of this study was to compare the expression of CD44 standard molecule with the International Neuroblastoma Pathology Classification (INPC) for neuroblastic tumours, a histological grading system based on the Shimada system for predicting the clinical outcome in neuroblastic tumours.
  4. Cheah PL, Looi LM, Nazarina AR, Goh KL, Rosmawati M, Vijeyasingam R
    Malays J Pathol, 2003 Jun;25(1):37-43.
    PMID: 16196376
    A study was conducted at the Department of Pathology, University of Malaya Medical Centre, Kuala Lumpur into the histological type (WHO classification), grade (modified Edmondson and Steiner's grading system), mitotic rate, bile production, hyaline globule and Mallory hyaline formation of 52 cases of hepatocellular carcinoma (HCC) diagnosed during a 13-year period between 1st January 1990 to 31st December 2002. In addition, associated cirrhosis, dysplasia (large liver cell dysplasia: LLCD and small liver cell dysplasia: SLCD) and microvascular permeation were also looked for whenever the situation permitted. The patients' ages ranged from 21-years to 85-years (mean = 58.7 years) with a predilection for males and Chinese. Histologically, majority (73.1%) of the tumours demonstrated a trabecular pattern of growth. The bulk (73%) of the tumours were either of grade II or III differentiation. Mitotic activity ranged between 0-100/10 high power fields (hpf) with a mean of 22.2/10 hpf. Bile was noted in 25%, hyaline globules 17.3% and Mallory bodies in one case. Concomitant cirrhosis was present in 73.5%. 73.5% of the cases had associated LLCD. 5 with LLCD also showed SLCD. Microvascular permeation was shown in 76.2% of cases. On comparison with findings from other studies, no major difference seems to exist between the histological characteristics of our HCC cases and that of other populations.
  5. Mohd A, Goh EM, Chow SK, Looi LM, Yeap SS
    PMID: 12971563
    The diagnosis of patients with fever of unknown origin (FUO) is often problematic because the range of possible differential diagnoses is broad. We report on a case in which a patient presented with FUO and was subsequently found to have both a collagen vascular disease and an intercurrent infection. Treatment for the collagen vascular disease with corticosteroids exacerbated the intercurrent infection. The problems in the diagnosis and management of such cases are discussed.
  6. Jamal N, Ng KH, McLean D, Looi LM, Moosa F
    AJR Am J Roentgenol, 2004 Mar;182(3):713-7.
    PMID: 14975974
    This study was undertaken to estimate mammographic breast glandularity in Malaysian women from radiographic data.
  7. Looi LM, Zubaidah Z, Cheah PL, Cheong SK, Gudum HR, Iekhsan O, et al.
    Malays J Pathol, 2004 Jun;26(1):13-27.
    PMID: 16190103
    Cancer is a major morbidity and mortality concern in Malaysia. Based on National Cancer Registry data, the Malaysian population is estimated to bear a cancer burden of about 40,000 new cases per year, and a cumulative lifetime risk of about 1:4. Cancer research in Malaysia has to consider needs relevant to our population, and resources constraints. Hence, funding bodies prioritise cancers of high prevalence, unique to our community and posing specific clinical problems. Cancer diagnosis is crucial to cancer management. While cancer diagnosis research largely aims at improvements in diagnostic information towards more appropriate therapy, it also impacts upon policy development and other areas of cancer management. The scope of cancer diagnosis upon which this paper is based, and their possible impact on other R&D areas, has been broadly categorized into: (1) identification of aetiological agents and their linkages to the development of precancer and cancer (impact on policy development, cancer prevention and treatment), (2) cancer biology and pathogenesis (impact on cancer prevention, treatment strategies and product development), (3) improvements in accuracy, sensitivity and specificity in cancer detection, monitoring and classification (impact on technology development) and (4) prognostic and predictive parameters (impact on treatment strategies). This paper is based on data collected by the Working Group on Cancer Diagnosis Research for the First National Conference on Cancer Research Coordination in April 2004. Data was collated from the databases of Institutions/Universities where the authors are employed, the Ministry of Science, Technology and Innovation (MOSTI) and targeted survey feedback from key cancer researchers. Under the 7th Malaysia Plan, 76 cancer projects were funded through the Intensified Research in Priority Areas (IRPA) scheme of MOSTI, amounting to almost RM15 million of grant money. 47(61.8%) of these projects were substantially in cancer diagnosis, accounting for 65.6% (RM 9.7 million) of cancer project funds. The 8th Malaysia Plan saw a change in research strategy. The IRPA agency fielded several top-down projects which encouraged a multicentre and multidisciplinary approach. This resulted in larger funding per project i.e. RM32 million for 49 projects. There was also a surge of interest in drug development and natural products. Because of this shift in direction, cancer diagnosis projects constituted only 51% of IRPA-funded cancer projects. Nonetheless funding for cancer diagnosis research has exceeded that of the 7th Malaysia Plan, being RM12.5 million by March 2004. The majority of such research is carried out at the Universities, engaging a large number of young scientists and postgraduate students (51 MSc and 21 PhD). A lot of research findings presented at scientific meetings have not yet been published and there is a glaring shortage of patents and commercialization of research findings (such as creation of test kits). Because diagnosis is very much a part of clinical practice, many researchers felt satisfied and confident that their work will be translated into practice and will significantly improve diagnostic services in Malaysia. National guidelines and consensus development on at least three malignancies i.e. breast cancer, oral cancer and lymphoma, have substantial basis in local R&D work. Problems encountered in research included (1) insufficient funding to realize research objectives, (2) lack of local expertise (most research assistants are inexperienced BSc graduates with no or minimal research experience), (3) inadequate technical support from vendors during equipment failure, (4) inexperienced Institutional development units to assist in product development, (5) lack of venture capital for commercialization of findings, and (6) inadequate incentives to undertake research. Researchers pointed out that plans to promote research should include the establishment of (1) regional and national cancer tissue banks, (2) a National Cancer Research Institute, (3) a dedicated cancer research fund, (4) a registry of cancer researchers, (5) national research coordinators, (6) improved coverage by the National Cancer Registry, (7) more international collaboration, (8) a better career structure for researchers, (9) improved Institutional support for product realization, and (10) better recognition for cancer researchers.
  8. Doustjalali SR, Yusof R, Yip CH, Looi LM, Pillay B, Hashim OH
    Electrophoresis, 2004 Jul;25(14):2392-401.
    PMID: 15274022
    We have analyzed unfractionated sera of newly diagnosed patients (n=10) with breast carcinoma (BC), prior to treatment, and patients (n=5) with fibrocystic disease of the breast (FDB) by two-dimensional gel electrophoresis (2-DE) and silver staining. The patients' 2-DE serum protein profiles obtained were then subjected to image analysis and compared to similar data generated from sera of normal healthy female controls (n=10) of the same range of age. The relative expression of alpha1-antichymotrypsin (ACT), clusterin, and complement factor B was significantly higher in all BC patients as compared to normal controls. However, the expression of alpha1-antitrypsin (AAT) in BC patients was apparently lower than that of the controls. Similar differential expression of ACT was detected in the FDB patients. The aberrant expression of the serum acute-phase proteins of patients with BC and FDB was confirmed by competitive enzyme-linked immunosorbent assay (ELISA). Similar altered proteins expression was also observed from immunohistochemical studies of malignant (n=5) and benign (n=5) breast lesions of the respective patients performed using antisera to the aberrantly expressed proteins. However, the malignant breast lesions were instead positively stained for AAT. The differential expression of the serum proteins was apparently abrogated when a six-month follow-up study was performed on nine of the BC patients subsequent to treatment.
  9. Gan WH, Thye YL, Chang SH, Chua CB, Looi LM, Tan SY
    Transplant Proc, 2004 Sep;36(7):2148-9.
    PMID: 15518779
  10. Amalourde A, Vinayaga P, Naveed N, Jamal A, Looi LM, Sengupta S
    Med J Malaysia, 2004 Dec;59 Suppl F:60-2.
    PMID: 15941166 MyJurnal
    Although all types of tumour and tumour-like conditions have been described to occur in the clavicle, they only contribute to less then 0.5% of all skeletal tumours. The incidence of primary chondrosarcoma of the clavicle is extremely rare. To our knowledge it has not been reported in Malaysia. We would like to highlight the possibility of chondrosarcoma as a differential diagnosis for a clavicular lesion.
  11. Ranganathan S, Moosa F, Kamarulzaman A, Looi LM
    Br J Radiol, 2005 Apr;78(928):353-4.
    PMID: 15774599
    Cryptococcus neoformans is a yeast like fungus, which is commonly found in bird droppings, especially pigeons. Most cases of cryptococcal infections occur in immunocompromised patients or in those who are on long term immunosuppressant therapies. Cryptococcal infection usually presents as a meningoencephalitis or a pulmonary infection. Skin, bone and genital infections are very rare. We report the second case of vaginal cryptococcossis to be reported in English literature and the first to be imaged with CT and MRI.
  12. Looi LM, Loh KC
    Malays J Pathol, 2005 Jun;27(1):23-7.
    PMID: 16676689
    Although microwave irradiation has been used in the histopathology laboratory for several years, there has been minimal published experimental data on its effects on the technical and staining quality of histological sections. Furthermore, it has not been clear whether the advantages gained in reduction of fixation and staining duration has been at the expense of increasing architectural distortion to the tissues. We report here our experience with computerised morphometric analysis to investigate glomerular artifacts caused by microwave-stimulated fixation of renal tissues. 39 rat and 33 human autopsy kidney samples were subjected to (1) fixation in neutral buffered formaldehyde (control), (2) microwave-stimulated fixation followed by neutral buffered formaldehyde, and (3) neutral buffered formaldehyde followed by microwave irradiation. In addition, the effect of post-fixation in 70% ethanol was also investigated. Microwave irradiation was delivered through a dedicated laboratory microwave oven at 80% power and at 55 degrees C for 3 minutes. The different fixation methods were compared with regards to shrinkage (distortion) to glomerular structures (glomeruli and Bowman's spaces) on H and E sections, as determined by morphometric image analysis using a temporary assembled-system consisting of a trinocular microscope, a digital video camera and personal computer. A FlashPoint VGA 3.3 film-grabber card was used to capture images for morphometric analysis by using a Scion Image program. Morphometric analysis of glomerular structures showed that microwaves caused more shrinkage to the area bounded by the Bowman's capsule than the glomerulus proper, but post-fixation with ethanol reduced this shrinkage. These findings have implications on the logistics of tissue preparation of renal biopsies in clinical practice.
  13. Looi LM
    Med J Malaysia, 2005 Jul;60 Suppl B:144-5.
    PMID: 16108199
    The liver biopsy has a unique place in the investigation of liver disease because the concepts and classification of liver disease are rooted in morphology. Today, the use of the liver biopsy has extended beyond that of diagnosis, to the assessment of disease progression, response to therapy and transplant rejection. To get the best out of the liver biopsy, it is necessary to appreciate the usefulness and limitations of the biopsy specimen. Aspects to consider include: (1) minimizing sampling errors, and appreciating that the changes in the biopsy may not be representative of the primary pathology, (2) good laboratory quality practices to avoid processing artifacts, which may render a biopsy undiagnosable, (3) the appropriate use of special stains and other laboratory techniques, (4) adoption of a systematic and algorithmic approach in the microscopic examination of the biopsy, and (5) good clinicopathological correlation.
  14. Shekhar K, Lye MS, Norlijah O, Ong F, Looi LM, Khuzaiah R, et al.
    Med J Malaysia, 2005 Aug;60(3):297-304.
    PMID: 16379183
    From July through December 1997, 11 previously healthy children in Peninsular Malaysia succumbed to an illness clinically characterised by an acute severe refractory left-ventricular failure, following a brief prodromal illness, in the midst of an outbreak of hand, foot and mouth disease (HFMD), similar to the reported experience in Sarawak and Taiwan. Retrospective reviews of the clinical features and results of laboratory, pathological and virological investigations of cases were conducted. The median age of the 11 case-patients was 31 months (range, 13 to 49 months); 6 were males. A brief prodromal illness of 3 days (range, 2 to 5 days) was characterised by fever (axillary temperature > 38 degrees C) (100%), oral ulcers (72%), extremity rashes (45%) and significant vomiting (55%). Upon hospitalisation, 7 of 11 case-patients had features suggestive of cardiogenic shock, while 4 of 11 case-patients developed shock during hospitalisation as evidenced by marked sustained tachycardia (heart rate > or = 180 beats per minute), poor peripheral pulses and peripheral perfusion, mottled extremities, pulmonary oedema (haemorrhagic pulmonary secretions in 8 of 11 cases during tracheal intubation, often precipitated by conservative crystalloid boluses, and radiographic evidence of acute pulmonary oedema in 5 of 7 cases) and markedly impaired left ventricular function on echocardiographic examination (7 of 7 cases). Three of 4 case-patients had aseptic meningitis while one case-patient also had an acute flaccid paraparesis. Despite supportive therapy, death occurred within a median of 13.4 hours following hospitalization. Post-mortem findings (all 8 specimens examined) consistently demonstrated brain-stem encephalitis with foci of neuronal necrosis and micro-abscesses. None of the 11 specimens examined revealed histological evidence of myocarditis. Enterovirus 71 (EV71) was detected in 10 of 11 case-patients, many (7) from various sterile tissue sites (5 from central nervous tissues). No other viruses were isolated or identified. Clinical features and pathological studies closely paralleled the reported experience in Sarawak and Taiwan. The uniform necropsy findings of necrotizing brain-stem encephalitis coupled with essentially normal myocardial histology, in concert with the concurrent and consistent detection of EV71 points to a primary EV71 encephalitis; as yet unclear neurogenic mechanisms may account for the cardiovascular manifestations.
  15. Nizlan MN, Selvakumar K, Looi LM, Kunasegaran R
    Juxtafacet cyst of the spine is a rare occurrence. Reports have described them as synovial cysts; ganglion cysts; extradural cysts as well as degenerative cysts of the spine. Patients may present with radicular pain, motor deficits, sensory disturbances, cauda equina syndrome and even myelopathy. Lumbar juxtafacet cysts may be confused clinically with prolapsed intervertebral discs or other conditions involving nerve root compression such as arachnoid cysts, ependymal cysts, dermoid cysts or teratomatous cysts. In the case of the juxtafacet cyst, surgical excision is usually curative. We report a case of spinal synovial juxtafacet cyst found intraoperatively in a case that was preoperatively diagnosed as prolapsed intervertebral disc. Synovial juxtafacet cyst of the spine should be considered as one of the differential diagnoses in patients, especially in older patients, presenting with nerve root compression.
  16. Cheah PL, Looi LM
    Malays J Pathol, 2006 Jun;28(1):1-5.
    PMID: 17694953 MyJurnal
    Sixteen low grade (LSIL), 22 high grade (HSIL) squamous intraepithelial lesions, 28 invasive (13 stage I and 15 stage II-IV) squamous cell carcinoma (SCC) and 15 benign cervices were immunohistochemically studied for involvement of Bcl-2 and Bax proteins in cervical carcinogenesis. 4-microm sections of the cases were immunostained for Bcl-2 (Clone 124: Dako) and Bax (Dako) and staining intensity was rated as 1 (light), 2 (moderate) and 3 (strong) and percentage cellular staining as 0 (negative), 1 (1-25%), 2 (26-50%), 3 (51-75%) and 4 (>75%) with score derived by multiplying staining intensity and percentage positivity. The cut-off value, indicating upregulated expression, was computed as >2 for Bcl-2 and >8 for Bax. Bcl-2 was upregulated (p < 0.05) in HSIL and Bax in SCC when compared with benign cervical squamous epithelium. Bcl-2 expression was confined to the lower third of the epithelium in the benign cervices and LSIL. In HSIL, expression reached the middle and upper thirds. 4 (30.8%) HSIL with upregulated Bcl-2 demonstrated intensification of staining around the basement membrane. SCCs showed "diffuse" (evenly distributed) or "basal" (intensified staining around the periphery of the invading tumour nests) expression of Bcl-2. Of the 5 SCCs with upregulated Bcl-2, 1 of 2 (50%) stage I and 3 (100%) stage II-IV tumours exhibited the "basal" pattern. Benign cervical squamous epithelium, LSIL, HSIL and SCC showed a generally diffuse Bax expression. Thus, Bcl-2 and Bax appeared to be upregulated at different stages of cervical carcinogenesis, Bcl-2 in HSIL and Bax after invasion. Intensification of staining of Bcl-2 at the basement membrane in some HSIL and SCC is interesting and may augur for increased aggressiveness.
  17. Tan EL, Looi LM, Sam CK
    Singapore Med J, 2006 Sep;47(9):803-7.
    PMID: 16924363
    Nasopharyngeal carcinoma (NPC) is an important cancer in Malaysia and is one of the major causes of cancer mortality in this country. This study evaluates the diagnostic and prognostic values in the quantitative relationship between the cell-free Epstein-Barr virus (EBV) deoxyribonucleic acid (DNA) load and the tumour burden.
  18. Jamal N, Ng KH, Looi LM, McLean D, Zulfiqar A, Tan SP, et al.
    Phys Med Biol, 2006 Nov 21;51(22):5843-57.
    PMID: 17068368
    We describe a semi-automated technique for the quantitative assessment of breast density from digitized mammograms in comparison with patterns suggested by Tabar. It was developed using the MATLAB-based graphical user interface applications. It is based on an interactive thresholding method, after a short automated method that shows the fibroglandular tissue area, breast area and breast density each time new thresholds are placed on the image. The breast density is taken as a percentage of the fibroglandular tissue to the breast tissue areas. It was tested in four different ways, namely by examining: (i) correlation of the quantitative assessment results with subjective classification, (ii) classification performance using the quantitative assessment technique, (iii) interobserver agreement and (iv) intraobserver agreement. The results of the quantitative assessment correlated well (r2 = 0.92) with the subjective Tabar patterns classified by the radiologist (correctly classified 83% of digitized mammograms). The average kappa coefficient for the agreement between the readers was 0.63. This indicated moderate agreement between the three observers in classifying breast density using the quantitative assessment technique. The kappa coefficient of 0.75 for intraobserver agreement reflected good agreement between two sets of readings. The technique may be useful as a supplement to the radiologist's assessment in classifying mammograms into Tabar's pattern associated with breast cancer risk.
  19. Looi LM, Cheah PL, Zhao W, Ng MH, Yip CH
    Malays J Pathol, 2006 Dec;28(2):83-6.
    PMID: 18376796 MyJurnal
    Metastasising ability connotes one of the most important life-threatening properties of malignant neoplasms. Recent studies indicate that CD44 proteins, multifunctional cell adhesion molecules which contribute to "homing" of lymphocytes to lymph nodes as well as cell-cell and cell-matrix interactions, are potential markers of tumour progression. However, whether CD44 expression by human tumours contribute to increased metastatic risk remains controversial. In an attempt to clarify its role in breast cancer, we have investigated the correlation between CD44 expression by breast carcinoma and the presence of axillary lymph node metastases. CD44 expression was detected using a standard immunoperoxidase method on formalin-fixed, paraffin-embedded, primary infiltrating ductal breast carcinoma tissues taken from 60 female patients who underwent mastectomy with axillary node clearance. Tumours were graded according to the modified Bloom and Richardson criteria. 62% of patients had histologically-proven lymph node metastasis. 40% of primary cancers exhibited cytoplasmic membrane immunopositivity for CD44. 46% of primary tumours which have metastasied to axillary lymph nodes were CD44 positive whereas 30% of tumours which have not metastasised expressed CD44. CD44 positivity was expressed by 20% of grade 1, 31% grade 2 and 58% grade 3 tumours. Our results suggest that CD44 may have a role in the progression of breast cancer and emphasise the need to investigate its interaction with other mechanisms of cancer advancement.
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