This study reports the results of mutation detection of tumour suppressor genes, p53 and RB2/p130 genes in Malaysian nasopharyngeal carcinoma (NPC) studied by PCR-CSGE analysis and direct DNA sequencing method. Frequent sites of mutation in both genes (exons 5-8 of p53 and exons 19-21 of RB2/p130) were examined. Thirty-six NPC blood samples and three NPC cell lines were investigated for the presence of mutations. No mutation of p53 and RB2/p130 genes was identified in any of the blood samples. Nonetheless, there was an identical G-->4 C nucleotide change at codon 280 of p53 gene in all the cell lines. A larger study that includes biopsy tissues should be carried out to provide a more in-depth look into the pathogenesis of NPC in Malaysia.
Hearing loss is a common sensory deficit in humans. The hearing loss may be conductive, sensorineural, or mixed, syndromic or nonsyndromic, prelingual or postlingual. Due to the complexity of the hearing mechanism, it is not surprising that several hundred genes might be involved in causing hereditary hearing loss. There are at least 82 chromosomal loci that have been identified so far which are associated with the most common type of deafness--non-syndromic deafness. However, there are still many more which remained to be discovered. Here, we report the mapping of a locus for autosomal recessive, non-syndromic deafness in a family in Malaysia. The investigated family (AC) consists of three generations--parents who are deceased, nine affected and seven unaffected children and grandchildren. The deafness was deduced to be inherited in an autosomal recessive manner with 70% penetrance. Recombination frequencies were assumed to be equal for both males and females. Using two-point lod score analysis (MLINK), a maximum lod score of 2.48 at 0% recombinant (Z = 2.48, theta = 0%) was obtained for the interval D14S63-D14S74. The haplotype analysis defined a 14.38 centiMorgan critical region around marker D14S258 on chromosome 14q23.2-q24.3. There are 16 candidate genes identified with positive expression in human cochlear and each has great potential of being the deaf gene responsible in causing non-syndromic hereditary hearing loss in this particular family. Hopefully, by understanding the role of genetics in deafness, early interventional strategies can be undertaken to improve the life of the deaf community.
Intense myelofibrosis is rarely associated with de novo acute myeloid leukaemia (AML) except in acute megakaryoblastic leukaemia (AML-M7) where there is diffuse marrow fibrosis as a consequence of proliferation of neoplastic myeloid cells. AML associated with significant myelofibrosis developing both de novo or secondary to primary (idiopathic) myelofibrosis is characterised by a fulminant course and extremely poor prognosis, primarily due to treatment-resistant disease. The prognostic value of degree of marrow fibrosis in de novo AML has been poorly investigated. We describe a case of extensive myelofibrosis associated with acute erythroblastic leukaemia (AML-M6) that responded to induction therapy of the leukaemia.
The molecular basis of variable phenotypes in P-thalassaemia patients with identical genotypes has been associated with co-inheritance of alpha-thalassaemia and persistence of HbF production in adult life. The Xmn I restriction site at -158 position of the Ggamma-gene is associated with increased expression of the Ggamma-globin gene and higher production of HbF This study aims to determine the frequency of the digammaferent genotypes of the Ggamma Xmn I polymorphism in P-thalassaemia patients in two ethnic groups in Malaysia. Molecular characterisation and frequency of the Ggamma Xmn I polymorphism were studied in fifty-eight Chinese and forty-nine beta-thalassaemia Malay patients by Xmn I digestion after DNA amplification of a 650 bp sequence. The in-house developed technique did not require further purification or concentration of amplified DNA before restriction enzyme digestion. The cheaper Seakem LE agarose was used instead of Nusieve agarose and distinct well separated bands were observed. Genotyping showed that the most frequent genotype observed in the Malaysian Chinese was homozygosity for the absence of the Xmn I site (-/-) (89.7%). In the Malays, heterozygosity of the Xmn I site (+/-) was most common (63.3%). Homozygosity for the Xmn I site (+/+) was absent in the Chinese, but was confirmed in 8.2% of the Malays. The ratio of the (+) allele (presence of the Xmn I site) to the (-) allele (absence of the Xmn I site)) was higher in the Malays (0.66) compared to the Chinese (0.05). The (+/-) and (+/+) genotypes are more commonly observed in the Malays than the Chinese in Malaysia.
This was a retrospective study of dentigerous cysts in people from the Singapore-Malaysian region. The purpose of this study was to present the clinicopathologic features of dentigerous cysts in the Oriental population and to compare these data with those from other reported studies. Biopsy records from 1981 to 1993 of 119 cases of dentigerous cysts from patients in Malaysia and Singapore showed that 36.1% of patients were female and 63.9% patients were male. Among patients with cysts, 70.5% were Chinese, 23.2% were Malays, 2.7% were Indian and 3.6% were other ethnic groups. The mean age of these patients was 30.2 +/- 17.3 years with a peak incidence occurring in the second and third decades. The location of the lesions was almost equal to the maxilla (50.9%) and the mandible (49.1%). There was a marked predilection for the posterior mandible (42.7%) followed by the anterior maxilla (38.2%). Histologically, 90.8% of the cysts were lined by a non-keratinised stratified squamous epithelium. The cyst linings were mainly thin (90.0%) with 38.7% of cases having a mixed thick and thin lining. Mucous metaplasia was observed in 9 (7.6%) cases. Rushton bodies were seen in 3.4% of cases. Cholesterol clefts in the epithelial lining and lumen were found in 16.8% cases while 12.6% of cases exhibited cholesterol clefts in the cyst wall. Other cellular structures within the cyst wall were lymphocytes (66.4%), plasma cells (52.1%), Russell bodies (16.0%) and histiocytes (4.2%). Odontogenic keratocysts were observed in 5.0% of cases. One case of adenomatoid odontogenic tumour was also observed. Epithelial atypia was seen in 9.2% of cases, islands of stratified squamous epithelial cells in 8.4% of cases while one case showed a combination of these two features. In conclusion, some clinical features seen in this study are similar to that for the Caucasian population such as prevalence in male, peak incidence in the second and third decades and the predilection for the posterior mandible and anterior maxilla. Histopathologically, odontogenic keratocyst and adenomatoid odontogenic tumour were observed in dentigerous cysts.
Hepatocellular carcinoma (HCC) ranks as the fifth most common cancer with an increasing frequency worldwide. "Nuclear atypia", one of the critical features in histological diagnosis of malignancy and grading of the tumour, is generally ascertained through eyeballing. A study was conducted at the Department of Pathology, University of Malaya Medical Centre to assess whether nuclear area, (surrogate measure for nuclear size) and standard deviation (surrogate measure for nuclear pleomorphism) when objectively measured via computer-linked image analysis differs between (1) benign and malignant liver cells and (2) different grades of HCC. A 4-microm thick H&E stained section of 52 histologically re-confirmed HCC with 36 having benign, non-dysplastic surrounding liver were analysed using the Leica Q550 CW system. 10 consecutive non-overlapping, non-mitotic and non-apoptotic nuclei of HCC and surrounding benign hepatocytes respectively were manually traced at 400x magnification on the computer monitor and the nuclear area for the particular cell computed in arbitrary units by the Leica QWIN software. A total of 360 benign hepatocytic nuclei, 240 low grade HCC and 280 high grade HCC nuclei were traced. The mean nuclear area of the benign hepatocytes (37.3) was significantly smaller (p < 0.05) than that of both low grade (65.2) and high grade HCC (80.0). In addition, the mean nuclear area of high grade HCC was significantly larger (p < 0.05) than the low grade HCC. SD of the nuclear areas was lowest in benign hepatocytes (9.3), intermediate in low grade HCC (25.0) and highest in high grade HCC (25.6). These findings indicate that computer-linked nuclear measurement may be a useful adjunct in differentiating benign from malignant hepatocytes, in particular in small biopsies of well-differentiated tumours, and in predicting survival after surgical resection and transplant.
The unique ability of tumour cells to proliferate indefinitely is crucial to neoplastic progression as it allows these cells to express the aggressive properties of cancer without the censure of physiological ageing. This is in contrast to normal somatic cells which are subject to a "mitotic clock," a phenomenon that has been linked to telomeric shortening after each round of cell replication, so that eventually the loss of genetic material reaches a critical stage and the cells undergo senescence and cell death. A study was conducted to investigate the role of telomerase, an RNA-containing enzyme that restores the telomere length, in the neoplastic cell immortalization and progression process. Fresh human tissue samples taken from excision specimens received by the Department of Pathology, University of Malaya Medical Centre, were investigated for telomerase activity using a commercial Telomerase PCR-ELISA kit (Boehringer Mannheim). Specimens comprised 33 breast lesions (10 infiltrating breast adenocarcinoma, 13 fibroadenoma and 10 non-neoplastic breast tissue), 27 colonic lesions (17 colonic adenocarcinoma and 10 non-neoplastic colonic mucosa) and 42 cervical lesions (20 cervical carcinoma and 22 non-neoplastic cervical tissues). Telomerase activity was found in 6 (60%) of 10 breast carcinomas, 6 (46%) of 13 fibroadenomas, none of the 10 nonneoplastic breast samples, 3 (17.6%) of 17 colon carcinomas and none of the 10 non-neoplastic colonic mucosal samples, 12 (60%) of 20 cervical carcinoma and 3 (13.6%) of 22 non-neoplastic cervical samples. 5/10 (50%) Stage I, 4/7 (57%) Stage II, 2/2 (100%) Stage III and 1/1 (100%) Stage IV cervical carcinomas showed telomerase activity. These findings support a contributory role for telomerase in tumourigenesis with activation occurring from neoplastic transformation and increasing with tumour progression.
Giardia duodenalis causes diarrhoea and malabsorption. The objectives of the study were to detect local isolates of G. doudenalis by polymerase chain reaction (PCR) and to determine their restriction fragment length polymorphisms (RFLP). G. doudenalis isolated from stools of patients from Hospital Orang Asli Gombak were cultured axenically using TYI-S-33 medium with 10% foetal calf serum. The commercially designed primer-pair 432/433 was used to amplify a 0.52 kb segment known to encode the homologous cysteine-rich trophozoite surface antigen (tsp11 and tsa417). Results showed that the primer-pair 432/433 could amplify the target region of the local isolates. RFLP study on the identical isolates showed that all the restriction enzymes tested ( HindIII, ClaI, PstI and Kpn) gave a banding pattern similar to that of the WB strain a reference pathogenic strain from human. The reference pathogenic strain were commercially obtained from the American Type Culture Collection (ATCC).
Owing to the importance of dendritic cells (DC) in the induction and control of immunity, an understanding of their biology is central to the development of potent immunotherapies for cancer, chronic infections, autoimmune disease, and induction of transplantation tolerance. This review surveys the heterogeneity of DC with regards to their phenotype and developmental origin, and how they initiate, modify and regulate the immune response, with emphasis on their maturation, migration, antigen-presentation and interaction with T cells and other immune cells. Much of this knowledge is obtained through research on murine DC. Research on human DC has been hampered by limitations associated with in vitro assays and limited access to human tissues. New approaches on human DC research are required in order to develop novel strategies for the treatment of microbial infections, the control of graft rejection, and the improvement of DC-based immunotherapeutic protocols for autoimmunity, allergy, and cancer.
Rosai-Dorfman disease (RDD) is a rare benign proliferative disorder of histiocytes in the lymph nodes with or without extranodal involvement. RDD limited to the skin without nodal involvement, known as cutaneous Rosai-Dorfman disease, is very rare. We describe a 34-year-old female with RDD of the skin over the chest. A large nodule with satellite lesions was excised for histopathological examination. Microscopically, there were many large histiocytes (Rosai-Dorfman cells) exhibiting emperipolesis, among many plasma cells, lymphocytes and neutrophils throughout the dermis and the subcutaneous tissue. The histiocytes were immunohistochemically positive for S-100 protein but negative for CD 1a. Physical examination showed no lymphadenopathy or any extra-cutaneous lesions. Serological tests indicated a past infection with Epstein-Barr virus and cytomegalovirus. The diagnosis of cutaneous RDD may be difficult in the absence of associated lymphadenopathy or any specific features of the skin lesion. Hence, not only is histopathological examination required for definitive diagnosis but a high index of suspicion by the clinicians and pathologists is essential to help diagnose this very rare disease.
Antimicrobial resistance to the extended-spectrum cephalosporins is increasingly reported worldwide. In the local setting, nosocomial infections with multi-resistant Gram-negative bacilli are not uncommon and are a growing concern. However, there is limited data on the carriage rates of such organisms in the local setting. In May 2001, a prospective study was carried out to determine the enteric carriage rates of ceftazidime-resistant Gram negative bacilli (CAZ-R GNB) among residents of nursing homes and from in-patients of the geriatric and adult haematology wards of University Malaya Medical Centre. Ceftazidime-resistant Gram-negative bacilli (CAZ-R GNB) were detected in 25 samples (30%), out of which 6 were from nursing home residents, 5 from geriatric in-patients and 14 from the haematology unit. A total of 28 CAZ-R GNB were isolated and Escherichia coli (10) and Klebsiella pneumoniae (7) were the predominant organisms. Resistance to ceftazidime in E. coli and Klebsiella was mediated by extended-spectrum beta-lactamases (ESBLs). Although the majority of the CAZ-R GNB were from patients in the haematology ward, the six nursing home residents with CAZ-R GNB were enteric carriers of ESBL-producing coliforms. Prior exposure to antibiotics was associated with carriage of ESBL organisms and to a lesser extent, the presence of urinary catheters.
Most previous studies on RET and p53 proteins have focused on thyroid papillary carcinoma. We investigated the role of RET and p53 protein expressions using immunohistochemistry on 52 cases of thyroid follicular adenomas and studied the follow-up records of these patients. The range of follow-up period was 3 to 14 years. The patients were between 15 and 71 years of age with a median age of 34.5 years. There were 46 females and 6 males. Except for 3 cases, all patients were Malays. The minimum volume of the tumour was 1000 mm3 and the maximum was 512,000 mm3 with a median of 270,000 mm3. Eleven (21.2%) cases showed RET expression. RET expression was not statistically significant when cross-tabulated against sex (p = 0.322), ethnicity (p = 0.518), age (p = 0.466) and symptom duration (p = 0.144). Six (11.5%) of 52 cases showed p53 immunopositivity. p53 expressions were also not significantly correlated to the clinical parameters above. There was no correlation between RET and p53 protein expressions. The only statistically significant finding was the association of tumour volume with duration of symptoms (p = 0.05). All patients are alive at the time of writing. 3 had recurrent goitre, 2 of these were diagnosed as colloid goitre while the third was a follicular lesion. One patient suffered from depression requiring anti-depressant treatment. In conclusion, unlike papillary carcinoma in which the roles of ret and p53 oncogenes are known, their roles in influencing the behaviour of follicular adenoma has not been ascertained.
Giardia duodenalis is an intestinal parasite that causes diarrhoea and malabsorption in children. The parasite also infects AIDS patients with a weak immune system. A study was carried out on six local isolates of Giardia duodenalis (110, 7304, 6304, M007, 2002 and 6307) from faeces of Orang Asli patients admitted to the Gombak Hospital. WB, a reference pathogenic strain from human and G. muris from a wild mouse, were commercially obtained from the American Type Culture Collection (ATCC). All the isolates were cultured axenically in TYI-S-33 medium. Two sets of primers were used for the techniques: primers LP1 and RP1 and primers LP2 and RP2. The sets of primers amplified giardine gene of 171 bp and 218 bp in sizes respectively. The study showed that the two sets of primers could detect G. duodenalis to the genus and species level specifically.
Colonic adenocarcinoma metastasising to the skeletal muscle is rare. A-56-yr-old Malay man was diagnosed to have adenocarcinoma of the right colon [Dukes B] for which a right hemicolectomy was performed, followed by radiotherapy and chemotherapy. Five years later the patient presented with a mass in the rectus abdominis muscle. The serum carcinoembryonic antigen was 71 ng/Ml. The mass was resected. Gross and microscopical examination showed multiple deposits of mucin-secreting adenocarcinoma with prominent heterotopic ossification in the stroma. The exact pathogenesis and significance of heterotopic ossification is not clear, but bone morphogenetic proteins may play an important role.
Metastatic eyelid tumours are rare and account for less than 2% of all eyelid neoplasms. We report a case of metastatic breast carcinoma to the eyelid in a 60-year-old Chinese lady presenting with a 2-year history of enlarging, painless nodular lower eyelid swelling. The 1 cm diameter lesion was provisionally diagnosed as a sebaceous cyst. However the excision biopsy revealed a mucinous carcinoma expressing oestrogen receptor protein. She had a past history of mastectomy one year previously and histology showed an infiltrating ductal carcinoma (oestrogen receptor status negative) without evidence of axillary lymph node metastasis. She had completed adjuvant radio- and chemotherapy. Further treatment of the current lesion involved a wide excision which did not show any residual malignancy. She had no other evidence of metastasis and was treated with letrozol. We highlight this case to create awareness among clinicians and opthalmologists on the possibility of metastatic disease as a cause of eyelid swelling, especially in patients with a history of cancer. It may also be the first sign of metastatic disease of an internal malignancy. A review of the literature is also presented.
A 62-year-old lady presented with a six-month history of swelling of the left upper eyelid, resulting in mild mechanical ptosis. Clinical assessment suggested a provisional diagnosis of dermoid cyst. The lesion was excised and histology revealed nodular deposits of amorphous eosinophilic material surrounded by lymphocytes and plasma cells. Special histochemistry and immunoperoxidase stain results showed deposition of amyloid, non-AA type. The lesion recurred 6 months later.
A mycological medium was developed for primary isolation and culture of lipophilic yeasts. It was initially based on published information of nutrients and trace components that would promote the growth of these yeasts. It was subsequently modified and adjusted to specifically promote the growth of lipophilic yeasts and simultaneously avoid the luxurious growth of other fungi and bacteria. With this medium, the conventional bacteriological procedures such as microbial streaking for pure culture and anti-microbial sensitivity testing could be carried out for these lipophilic yeasts.
AIM: To study the clinical features, histology and immunohistochemical properties of gastrointestinal stromal tumours (GISTs); and establish any parameters that can help prognosticate the malignant potential.
METHODS: Twenty-six patients with GISTs who were seen in Sultanah Aminah Hospital Johor, Malaysia from 1999 to 2003 were selected for study. Patient, clinical characteristics and outcome based on surgical records were analysed. Tumour variables (tumour size, cellularity, mitotic count, necrosis and haemorrhage) were compared between very low to low risk groups and intermediate to high risk groups. The immunohistochemical properties of GISTs were also studied.
RESULTS: Patients with GISTs presented mainly with pain, palpable mass or gastrointestinal tract bleeding. The tumours were seen in stomach (50%) followed by small intestine (38.5%) and rectum (11.5%). In the period of study, six patients had metastasis, mainly in the liver or peritoneum. Immunoreactivity for CD117, CD34, vimentin, S100, neuron specific enolase, alpha-smooth-muscle-actin and desmin were observed in 100%, 76.9%, 61.5%, 46.1%, 80.8%, 11.5% and 0% of tumours respectively. The behaviour of GISTs was largely dependent on tumour size and number of mitosis. Necrosis and haemorrhage were seen in tumours with high risk potential.