Medicine
Permanent URI for this communityhttp://repository.kln.ac.lk/handle/123456789/12
This repository contains the published and unpublished research of the Faculty of Medicine by the staff members of the faculty
Browse
3 results
Search Results
Item Modified mismatch polymerase chain reaction-restriction fragment length polymorphism detected mutations in codon 12 and 13 of exon 2 of K-ras gene in colorectal cancer patients and its association with liver metastases: Data from a South Asian country(Medknow Publications, 2016) Faleel, F.D.; Zoysa, M.I.; Lokuhetti, M.D.; Gunawardene, Y.I.N.S.; Chandrasekharan, N.V.; Dassanayake, R.S.AIM: Mutations in K-ras codon 12 and 13 of exon 2 are known to affect prognosis and impart resistance to anti-epidermal growth factor monoclonal antibody therapy in colorectal carcinoma (CRC). Our aim was to investigate the utility value of modified mismatch polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay to detect mutation in K-ras codons of CRC patients and to relate the mutational status to liver metastasis. METHODOLOGY: Mismatch PCR-RFLP was developed to detect K-ras mutations in DNA isolated from paraffinized tumor tissue of thirty CRC patients. All patients had 5 year follow-up data to detect liver metastasis. Cross-tabulations were generated between K-ras mutations and the metastatic status. The Chi-square test was used to indicate statistical significance of the association. RESULTS: Of the 30 CRC patients investigated, K-ras mutations of codons 12 and/or 13 of exon 2 were detected in 14 (46.6%). Meanwhile, 13 patients (43.3%) were observed to have developed liver metastases. There was a significant association between the presence of the K-ras mutation in codon 12 and the occurrence of liver metastasis (χ2 = 4.693, P = 0.030) on the contrary to the mutation in codon 13 to which such occurrence of liver metastases was not seen (χ2 = 1.884, P = 0.169). CONCLUSION: Codon 12 of exon 2 of K--ras gene detected by modified mismatch PCR-RFLP assay is significantly associated with liver metastasis in CRC patients during the first 5 years after surgery. Thus, modified mismatch PCR-RFLP protocol is a suitable method in this setting to detect K-ras gene mutations predicting liver metastasis in CRC patients.Item Clinical utility of PCR and real time PCR assays for Cytomegalovirus, hepatitis B and hepatitis C infections.(Sri Lanka Association for the Advancement of Science, 2008) Dassanayake, R.S.; de Silva, P.; Weerasena, J.; Gunawardene, Y.I.N.S.; Manamperi, A.Molecular Medicine Unit, Faculty of Medicine, University of Kelaniya, Reactivation of cytomegalovirus (CMV), Hepatitis B (HBV) and C (HCV) viruses from the status of latency is seen in immunocompromised individuals and such reactivation is often associated with morbidity and mortality in such individuals. The prevalence of these viral infections in a selected population of patients referred to the Molecular Diagnostic Laboratory at the Durdan's Hospital, Colombo, during the period from August 2007 to May 2008 were studied using qualitative PCR assays. All specimens from patients with suspected clinical diagnoses of either CMV or HBV or HCV infections were analyzed. Of 176 samples analyzed for CMV 78 were positive (37 males, 29 females) and majority of them are patients from a nephrology unit. Out of 40 and 10 samples analyzed from males and females, respectively, 22 and 4 were positive for HBV. Twenty six samples were analyzed for HCV and only 6 were fond to be infected with viruses and all of them were from males. Although PCR detection of these viral DNA/RNA is a sensitive method to detect infection, it lacks specificity for the detection of active viral disease and for monitoring the efficacy of antiviral therapy. Therefore, Real-time PCR (RT-PCR) assays for the detection and quantification of CMV-DNA, HBV-DNA and HCV-RNA were developed using SYBRgreen1 chemistry. The assays developed are capable of detecting viral particles in blood samples and quantifying viral DNA accurately over a broad range of input target copies (102 - 108copies/ml) and therefore, can be used to predict the reactivation of viruses by comparing with published kinetic criteria in clinical guidelines. Post PCR analyses of Real-time PCR products by agarose gel electrophoresis revealed bands having the same intensity for a wide range of target copies (103 -108copies/ml). In contrast, RT-PCR elicited higher cycle threshold for the descending order of concentration of target copies. Therefore, based on these results, it is evident that the intensity of conventional PCR bands should not be used for the assessment of viral reactivation or for monitoring therapeutic intervention and for this purpose RT-PCR is the method of choiceItem Rapid differential diagnosis of dengue and chikungunya infections by multiplex RT-PCR and impact of chikungunya infection on liver biochemical tests(Sri Lanka Association for the Advancement of Science, 2008) Manamperi, A.; de Silva, P.; Ekanayaka, C.; Gunawardene, Y.I.N.S.; de Silva, J.; Weerasena, O.V.D.S.J.; Dassanayake, R.S.