Down-regulation of complement genes in lipopolysaccharidechallenged zebrafish (Danio rerio) larvae exposed to Indonesian propolis / Regulação negativa dos genes do complemento em larvas de peixe-zebra (Danio rerio) desafiadas com lipopolissacarídeo expostas à própolis indonésia

Although propolis has been reported for having anti-inflammatory activities, its effects on complement system has not been much studied. This research was conducted to find out the effects of Indonesian propolis on the expression levels of C3, C1r/s, Bf, MBL, and C6 in zebrafish larvae which were induced by lipopolysaccharide (LPS). Counting of macrophages migrating to yolk sac and liver histology were carried out. Larvae were divided into four groups: CON (cultured in E3 medium only), LPS (cultured in a medium containing 0.5 μg/L LPS), LPSIBU (cultured in a medium containing LPS, and then treated with 100 μg/L ibuprofen for 24 hours), and LPSPRO (cultured in a medium containing LPS, and then immersed in 14,000 μg/L propolis for 24 hours) groups. The results showed that complement gene expression in larvae from the LPSIBU and LPSPRO groups were generally lower than in larvae from the LPS group. The number of macrophage migrations to the yolk in the LPSPRO group was also lower than in the LPS group. Histological structure of liver in all groups were considered normal. This study shows that Indonesian propolis has the potential to be used as an alternative to the substitution of NSAIDs.

Embora a própolis tenha sido relatada por ter atividade anti-inflamatória, seus efeitos no sistema complemento, uma parte do sistema imunológico inato, não foram muito estudados. Esta pesquisa foi conduzida para descobrir os efeitos da própolis da Indonésia nos níveis de expressão de C3, C1r/s, Bf, MBL e C6 em larvas de peixe-zebra induzidas por lipopolissacarídeo (LPS). Foram realizadas contagens de macrófagos que migram para o saco vitelino e histologia do fígado. As larvas foram divididas em quatro grupos: CON (cultivadas apenas em meio E3), LPS (cultivadas em meio contendo 0,5 μg/L de LPS), LPSIBU (cultivadas em meio contendo LPS e, em seguida, tratadas com 100 μg/L de ibuprofeno por 24 horas) e LPSPRO (cultivado em meio contendo LPS, e então imerso em própolis 14,000 μg/L por 24 horas). Os resultados mostraram que a expressão do gene do complemento em larvas dos grupos LPSIBU e LPSPRO foi geralmente menor que em larvas do grupo LPS. O número de migrações de macrófagos para a gema no grupo LPSPRO também foi menor que no grupo LPS. A estrutura histológica do fígado em todos os grupos foi considerada normal. Este estudo mostra que a própolis indonésia tem potencial para ser utilizada como alternativa na substituição dos AINEs (anti-inflamatórios não esteroides).

Down-regulation of complement genes in lipopolysaccharide-challenged zebrafish (Danio rerio) larvae exposed to Indonesian propolis

Abstract Although propolis has been reported for having anti-inflammatory activities, its effects on complement system has not been much studied. This research was conducted to find out the effects of Indonesian propolis on the expression levels of C3, C1r/s, Bf, MBL, and C6 in zebrafish larvae which were induced by lipopolysaccharide (LPS). Counting of macrophages migrating to yolk sac and liver histology were carried out. Larvae were divided into four groups: CON (cultured in E3 medium only), LPS (cultured in a medium containing 0.5 g/L LPS), LPSIBU (cultured in a medium containing LPS, and then treated with 100 g/L ibuprofen for 24 hours), and LPSPRO (cultured in a medium containing LPS, and then immersed in 14,000 g/L propolis for 24 hours) groups. The results showed that complement gene expression in larvae from the LPSIBU and LPSPRO groups were generally lower than in larvae from the LPS group. The number of macrophage migrations to the yolk in the LPSPRO group was also lower than in the LPS group. Histological structure of liver in all groups were considered normal. This study shows that Indonesian propolis has the potential to be used as an alternative to the substitution of NSAIDs.

Resumo Embora a própolis tenha sido relatada por ter atividade anti-inflamatória, seus efeitos no sistema complemento, uma parte do sistema imunológico inato, não foram muito estudados. Esta pesquisa foi conduzida para descobrir os efeitos da própolis da Indonésia nos níveis de expressão de C3, C1r/s, Bf, MBL e C6 em larvas de peixe-zebra induzidas por lipopolissacarídeo (LPS). Foram realizadas contagens de macrófagos que migram para o saco vitelino e histologia do fígado. As larvas foram divididas em quatro grupos: CON (cultivadas apenas em meio E3), LPS (cultivadas em meio contendo 0,5 g/L de LPS), LPSIBU (cultivadas em meio contendo LPS e, em seguida, tratadas com 100 g/L de ibuprofeno por 24 horas) e LPSPRO (cultivado em meio contendo LPS, e então imerso em própolis 14,000 g/L por 24 horas). Os resultados mostraram que a expressão do gene do complemento em larvas dos grupos LPSIBU e LPSPRO foi geralmente menor que em larvas do grupo LPS. O número de migrações de macrófagos para a gema no grupo LPSPRO também foi menor que no grupo LPS. A estrutura histológica do fígado em todos os grupos foi considerada normal. Este estudo mostra que a própolis indonésia tem potencial para ser utilizada como alternativa na substituição dos AINEs (anti-inflamatórios não esteroides).

Down-regulation of complement genes in lipopolysaccharide-challenged zebrafish (Danio rerio) larvae exposed to Indonesian propolis / Regulação negativa dos genes do complemento em larvas de peixe-zebra (Danio rerio) desafiadas com lipopolissacarídeo expostas à própolis indonésia

Abstract Although propolis has been reported for having anti-inflammatory activities, its effects on complement system has not been much studied. This research was conducted to find out the effects of Indonesian propolis on the expression levels of C3, C1r/s, Bf, MBL, and C6 in zebrafish larvae which were induced by lipopolysaccharide (LPS). Counting of macrophages migrating to yolk sac and liver histology were carried out. Larvae were divided into four groups: CON (cultured in E3 medium only), LPS (cultured in a medium containing 0.5 μg/L LPS), LPSIBU (cultured in a medium containing LPS, and then treated with 100 μg/L ibuprofen for 24 hours), and LPSPRO (cultured in a medium containing LPS, and then immersed in 14,000 μg/L propolis for 24 hours) groups. The results showed that complement gene expression in larvae from the LPSIBU and LPSPRO groups were generally lower than in larvae from the LPS group. The number of macrophage migrations to the yolk in the LPSPRO group was also lower than in the LPS group. Histological structure of liver in all groups were considered normal. This study shows that Indonesian propolis has the potential to be used as an alternative to the substitution of NSAIDs.

Resumo Embora a própolis tenha sido relatada por ter atividade anti-inflamatória, seus efeitos no sistema complemento, uma parte do sistema imunológico inato, não foram muito estudados. Esta pesquisa foi conduzida para descobrir os efeitos da própolis da Indonésia nos níveis de expressão de C3, C1r/s, Bf, MBL e C6 em larvas de peixe-zebra induzidas por lipopolissacarídeo (LPS). Foram realizadas contagens de macrófagos que migram para o saco vitelino e histologia do fígado. As larvas foram divididas em quatro grupos: CON (cultivadas apenas em meio E3), LPS (cultivadas em meio contendo 0,5 μg/L de LPS), LPSIBU (cultivadas em meio contendo LPS e, em seguida, tratadas com 100 μg/L de ibuprofeno por 24 horas) e LPSPRO (cultivado em meio contendo LPS, e então imerso em própolis 14,000 μg/L por 24 horas). Os resultados mostraram que a expressão do gene do complemento em larvas dos grupos LPSIBU e LPSPRO foi geralmente menor que em larvas do grupo LPS. O número de migrações de macrófagos para a gema no grupo LPSPRO também foi menor que no grupo LPS. A estrutura histológica do fígado em todos os grupos foi considerada normal. Este estudo mostra que a própolis indonésia tem potencial para ser utilizada como alternativa na substituição dos AINEs (anti-inflamatórios não esteroides).

Performance of selected SARS-CoV-2 antibodies immunoassays.

No abstract available.

Down-regulation of complement genes in lipopolysaccharide-challenged zebrafish (Danio rerio) larvae exposed to Indonesian propolis.

Although propolis has been reported for having anti-inflammatory activities, its effects on complement system has not been much studied. This research was conducted to find out the effects of Indonesian propolis on the expression levels of C3, C1r/s, Bf, MBL, and C6 in zebrafish larvae which were induced by lipopolysaccharide (LPS). Counting of macrophages migrating to yolk sac and liver histology were carried out. Larvae were divided into four groups: CON (cultured in E3 medium only), LPS (cultured in a medium containing 0.5 µg/L LPS), LPSIBU (cultured in a medium containing LPS, and then treated with 100 µg/L ibuprofen for 24 hours), and LPSPRO (cultured in a medium containing LPS, and then immersed in 14,000 µg/L propolis for 24 hours) groups. The results showed that complement gene expression in larvae from the LPSIBU and LPSPRO groups were generally lower than in larvae from the LPS group. The number of macrophage migrations to the yolk in the LPSPRO group was also lower than in the LPS group. Histological structure of liver in all groups were considered normal. This study shows that Indonesian propolis has the potential to be used as an alternative to the substitution of NSAIDs.

HIV-2 Infection in Malaysia: Current situation and the use of in-house real-time reverse transcription PCR for HIV-2.

HIV-2 surveillance has been carried out in Malaysia for more than 25 years ago. Tests to discriminate HIV-1 and HIV-2 are available but the options of test are limited and the need to develop a new in-house HIV-2 real-time reverse transcription PCR (RT-PCR) is crucial. A study was done on 29 samples from hospitals in Malaysia which were found to be positive screening for HIV-2 antibodies by the commercial Western Blot assay. These samples were further tested by a Western Blot assay that detects specific antibodies to HIV-2. Detection of HIV-2 genome was then performed by using a commercial kit. Fifteen samples were evaluated by using in-house real-time RT-PCR for HIV-2. Ninety-three percent (27/29) of samples have positive results for HIV-2 on HIV-2 Western Blot with only 2 samples showing indeterminate results. All samples showed negative results for HIV-2 genomes by using a PCR commercial kit and the 15 samples that were subjected to our in-house real-time RT-HIV-2 PCR were also tested negative for HIV-2 RNA. Results of HIV-2 Western Blot did not reflect the actual positivity as both HIV-1 and HIV-2 antibodies may cross-react with either viral proteins. None of the samples was confirmed positive for HIV-2 by the commercial and in-house real-time RTPCR. In-house real-time RT-HIV-2 PCR assay can be further used to confirm the presence of HIV-2 genome. Up to the year 2015, Malaysia is still free from HIV-2 infection.

HIV-2 Infection in Malaysia: Current situation and the use of in-house real-time reverse transcription PCR for HIV-2

@#HIV-2 surveillance has been carried out in Malaysia for more than 25 years ago. Tests to discriminate HIV-1 and HIV-2 are available but the options of test are limited and the need to develop a new in-house HIV-2 real-time reverse transcription PCR (RT-PCR) is crucial. A study was done on 29 samples from hospitals in Malaysia which were found to be positive screening for HIV-2 antibodies by the commercial Western Blot assay. These samples were further tested by a Western Blot assay that detects specific antibodies to HIV-2. Detection of HIV-2 genome was then performed by using a commercial kit. Fifteen samples were evaluated by using in-house real-time RT-PCR for HIV-2. Ninety-three percent (27/29) of samples have positive results for HIV-2 on HIV-2 Western Blot with only 2 samples showing indeterminate results. All samples showed negative results for HIV-2 genomes by using a PCR commercial kit and the 15 samples that were subjected to our in-house real-time RT-HIV-2 PCR were also tested negative for HIV-2 RNA. Results of HIV-2 Western Blot did not reflect the actual positivity as both HIV-1 and HIV-2 antibodies may cross-react with either viral proteins. None of the samples was confirmed positive for HIV-2 by the commercial and in-house real-time RTPCR. In-house real-time RT-HIV-2 PCR assay can be further used to confirm the presence of HIV-2 genome. Up to the year 2015, Malaysia is still free from HIV-2 infection.

Changes in health-related quality of life of oral cancer patients treated with curative intent: experience of a developing country.

This study aimed to assess changes in oral cancer patients' health-related quality of life (HRQOL) and the impact of disease stage on HRQOL scores. HRQOL data were collected from seven hospital-based centres using the Functional Assessment of Cancer Therapy-Head and Neck (FACT-H&N) version 4.0 instrument. The independent samples t-test, χ2 test, and paired samples t-test were used to analyse the data. A total of 300 patients were recruited. The most common oral cancer sub-site was tongue and floor of mouth (42.6%). Surgical intervention (41.1%) was the most common treatment modality. Significant differences in ethnicity and treatment modality were observed between early and late stage patients. Pre-treatment HRQOL scores were significantly lower for late than early stage patients. At 1 month post-treatment, the functional and head and neck domains and the FACT-H&N (TOI) summary scores showed significant deterioration in both early and late stage patients. In contrast, the emotional domain showed a significant improvement for early and late stage patients at 1, 3, and 6 months post-treatment. Although HRQOL deterioration was still observed among early and late stage patients at 6 months post-treatment, this was not statistically significant. In conclusion, advanced disease is associated with poorer HRQOL. Although ethnic differences were observed across different disease stages, the influence of ethnicity on patient HRQOL was not evident in this study.

Drug resistance mutations among virological failure HIV-1 infected patients in Malaysia.

The determination of HIV drug resistance mutations (DRMs) towards antiretroviral (ARV) drugs among HIV-1 treated patients with virological failure is crucial for further management of the patient. This study aimed to assess the most common genomic mutation and to analyse subtypes among the HIV-1 patients with viral load level > 1,000 copies/mL. A total of 101 virological failure HIV-1 patients from four different regions of Peninsular Malaysia with a viral load measurement facility were included in the study. Majority of patients (89.1%) have at least 1 mutation associated with clinical resistance to either protease inhibitors (PIs), nucleoside reverse transcriptase inhibitors (NRTIs) or nonnucleoside reverse transcriptase inhibitors (NNRTIs). Major resistance mutations among the patients towards NRTIs and NNRTIs were 70.3% and 18.8%, respectively. The most common mutation for NRTIs was M184V while K103N mutation was detected in the majority of patients who were treated with NNRTIs. The most commonly observed mutations for major PI and minor PI seen among the study population were V82A/T and L10V, respectively. In HIV-1 subtype analysis, CRF33_01B was the most predominant HIV-1 subtype in this study group. The vast detection of DRMs in this study emphasized the importance of genotypic resistance test in the management of HIV patients as DRMs can alter patient's susceptibility towards ARV drugs. Further study on larger number of samples is essential for the development of a database on HIV-1 DRMs among patients that experience virological failure in Malaysia.

Drug resistance mutations among virological failure HIV-1 infected patients in Malaysia

The determination of HIV drug resistance mutations (DRMs) towards antiretroviral (ARV) drugs among HIV-1 treated patients with virological failure is crucial for further management of the patient. This study aimed to assess the most common genomic mutation and to analyse subtypes among the HIV-1 patients with viral load level > 1,000 copies/mL. A total of 101 virological failure HIV-1 patients from four different regions of Peninsular Malaysia with a viral load measurement facility were included in the study. Majority of patients (89.1%) have at least 1 mutation associated with clinical resistance to either protease inhibitors (PIs), nucleoside reverse transcriptase inhibitors (NRTIs) or nonnucleoside reverse transcriptase inhibitors (NNRTIs). Major resistance mutations among the patients towards NRTIs and NNRTIs were 70.3% and 18.8%, respectively. The most common mutation for NRTIs was M184V while K103N mutation was detected in the majority of patients who were treated with NNRTIs. The most commonly observed mutations for major PI and minor PI seen among the study population were V82A/T and L10V, respectively. In HIV-1 subtype analysis, CRF33_01B was the most predominant HIV-1 subtype in this study group. The vast detection of DRMs in this study emphasized the importance of genotypic resistance test in the management of HIV patients as DRMs can alter patient’s susceptibility towards ARV drugs. Further study on larger number of samples is essential for the development of a database on HIV-1 DRMs among patients that experience virological failure in Malaysia.

Establishing and managing a periodontal biobank for research: the sharing of experience.

Periodontal bio-repositories, which allow banking of clinically validated human data and biological samples, provide an opportunity to derive biomarkers for periodontal diagnosis, prognosis and therapeutic activities which are expected to improve patient management. This article presents the establishing of the Malaysian Periodontal Database and Biobank System (MPDBS) which was initiated in 2011 with the aim to facilitate periodontal research. Partnerships were established with collaborating centres. Policies on specimen access, authorship and acknowledgement policies were agreed upon by all participating centres before the initiation of the periodontal biobank. Ethical approval for the collection of samples and data were obtained from institutional ethics review boards. A broad-based approach for informed consent was used, which covered areas related to quality of life impacts, genetics and molecular aspects of periodontal disease. Sample collection and processing was performed using a standardized protocol. Biobanking resources such as equipment and freezers were shared with the Malaysian Oral Cancer Database and Tissue Bank System (MOCDTBS). In the development of the MPDBS, challenges that were previously faced by the MOCDTBS were considered. Future challenges in terms of ethical and legal issues will be faced when international collaborations necessitate the transportation of specimens across borders.

Seropositivity of HPV 16 E6 and E7 and the risk of oral cancer.

OBJECTIVES: The objective of the study was to determine the prevalence of HPV seropositivity among patients with oral squamous cell carcinoma (OSCC) and healthy individuals and to correlate the association between HPV 16 seropositivity and risk of OSCC. MATERIALS AND METHODS: HPV 16 E6 and E7 plasmids were constructed for the production of recombinant protein, which was used as the antigen in ELISA. HPV ELISA was performed on serum samples from 50 healthy individuals and 50 patients with OSCC. RESULTS: Using the HPV ELISA, 30% (OR = 2.25, 95% CI = 0.85-5.93) and 18% (OR = 1.61, 95% CI = 0.53-4.92) of patients with oral cancer were found to be HPV 16 E6 and E7 seropositive, respectively. Significant association was found between HPV 16 seropositivity and increased risk of OSCC in men, but not in male subjects. A similar trend was observed in non-betel quid chewers. CONCLUSIONS: Potential associations between HPV 16 E6/E7 seropositivity and oral cancer were revealed in men and non-betel quid chewer subjects, suggesting a possible etiological role of HPV 16 in subgroup of patients with OSCC in Malaysia.

Dysregulation of miR-31 and miR-375 expression is associated with clinical outcomes in oral carcinoma.

OBJECTIVES: To identify differentially expressed miRNA between oral squamous cell carcinoma (OSCC) and non-cancer (NC) and to associate these with clinico-pathological parameters. MATERIALS AND METHODS: miRNA microarray profiling was utilized to obtain the expression profile of miRNAs in four OSCC and four NC samples. The expression of miR-31 and miR-375 was further validated in 26 OSCC and three NC samples using real-time-PCR. The association between miRNA expression and clinico-pathological parameters was tested by univariate and multivariate analyses. RESULTS: Microarray profiling demonstrated that 15 and four miRNAs were up-regulated and down-regulated, respectively, in OSCC as compared with NC. miR-31 and miR-375 were validated as up- and down-regulated miRNAs, respectively. In univariate analyses, expression of miR-31 was significantly elevated in early stage, tumours with no metastatic nodes and those from the buccal mucosa. By contrast, low miR-375 expression was significantly associated with late stage disease, larger tumour size and the non-cohesive type of pattern of invasion in OSCC. The association between miR-31 expression with tumour staging and site and miR-375 with tumour staging remained significant in multivariate analyses. CONCLUSIONS: This study has identified 19 miRNAs significantly associated with OSCC, and expressions of miR-31 and miR-375 were significantly related with clinico-pathological parameters suggesting they could be important in driving oral tumourigenesis.

Genome-wide analysis of oral squamous cell carcinomas revealed over expression of ISG15, Nestin and WNT11.

BACKGROUND: Multistep pathways and mechanisms are involved in the development of oral cancer. Chromosomal alterations are one of such key mechanisms implicated oral carcinogenesis. Therefore, this study aims to determine the genomic copy number alterations (CNAs) in oral squamous cell carcinoma (OSCC) using array comparative genomic hybridization (aCGH) and in addition attempt to correlate CNAs with modified gene expression. MATERIALS AND METHODS: Genome-wide screening was performed on 15 OSCCs using high-density aCGH. On the basis of pathway analysis, three genes (ISG15, Nestin and WNT11) which mapped to CNA regions were selected for further evaluation of their mRNA expression using quantitative reverse transcriptase PCR (qRT-PCR). RESULTS: Copy number alterations were observed on multiple genomic regions, including amplifications on 1p, 3q, 5p, 6p, 7p, 8q, 9q, 11q, 12q, 16p, 18p and deletions on 3p, 7q, 8p, 11q, 19q and 20q. Among the three selected genes, ISG15 had the highest mRNA expression level with a 22.5-fold increase, followed by Nestin with a 4.5-fold increase and WNT11 with a 2.5-fold increase. CONCLUSIONS: This study has identified several major CNAs in oral cancer genomes and indicated that this correlates with over expression of the ISG15, WNT11, and Nestin genes.

Advancing oral medicine through informatics and information technology: a proposed framework and strategy.

The implementation of information technology in healthcare is a significant focus for many nations around the world. However, information technology support for clinical care, research and education in oral medicine is currently poorly developed. This situation hampers our ability to transform oral medicine into a 'learning healthcare discipline' in which the divide between clinical practice and research is diminished and, ultimately, eliminated. This paper reviews the needs of and requirements for information technology support of oral medicine and proposes an agenda designed to meet those needs. For oral medicine, this agenda includes analyzing and reviewing current clinical and documentation practices, working toward progressively standardizing clinical data, and helping define requirements for oral medicine systems. IT professionals can contribute by conducting baseline studies about the use of electronic systems, helping develop controlled vocabularies and ontologies, and designing, implementing, and evaluating novel systems centered on the needs of clinicians, researchers and educators. Successfully advancing IT support for oral medicine will require close coordination and collaboration among oral medicine professionals, information technology professionals, system vendors, and funding agencies. If current barriers and obstacles are overcome, practice and research in oral medicine stand ready to derive significant benefits from the application of information technology.

Transcriptional profiling of oral squamous cell carcinoma using formalin-fixed paraffin-embedded samples.

Despite the advances in cancer treatment, the 5-year survival rate for oral cancer has not changed significantly for the past 40 years and still remains among the worst of all anatomic sites. Gene expression microarrays have been used successfully in the identification of genetic alterations in cancer development, however, these have hitherto been limited by the need for specimens with good quality intact RNA. Here, we demonstrated the use of formalin-fixed paraffin-embedded tissues in microarray experiments to identify genes differentially expressed between cancerous and normal oral tissues. Forty-three tissue samples were macrodissected and gene expression analyses were conducted using the Illumina DASL assay. We report RNA yield of 2.4 and 0.8 microg/mm(3) from tumour and normal tissues, respectively and this correlated directly with the tissue volume used for RNA extraction. Using unsupervised hierarchical clustering, distinct gene expression profiles for tumour and normal samples could be generated, and differentially expressed genes could be identified. The majority of these genes were involved in regulation of apoptosis and cell cycle, metastasis and cell adhesion including BCL2A1, BIRC5, MMP1, MMP9 and ITGB4. Representative genes were further validated in independent samples suggesting that these genes may be directly associated with oral cancer development. The ability to conduct microarrays on formalin-fixed paraffin-embedded specimens represents a significant advancement that could open up avenues for finding genes that could be used as prognostication and predictive tools for cancer.

Gene expression in human oral squamous cell carcinoma is influenced by risk factor exposure.

Oral squamous cell carcinoma (OSCC) is a world health problem and is associated with exposure to different risk factors. In the west, smoking and alcohol consumption are considered to be the main risk factors whilst in India and southeast Asia, betel quid (BQ) chewing is predominant. In this study, we compared the gene expression patterns of oral cancers associated with BQ chewing to those caused by smoking using Affymetrix microarrays. We found that 281 genes were differentially expressed between OSCC and normal oral mucosa regardless of aetiological factors including MMP1, PLAU, MAGE-D4, GNA12, IFITM3 and NMU. Further, we identified 168 genes that were differentially expressed between the BQ and smoking groups including CXCL-9, TMPRSS2, CA12 and RNF24. The expression of these genes was validated using qPCR using independent tissue samples. The results demonstrate that whilst common genes/pathways contribute to the development of oral cancer, there are also other gene expression changes that are specific to certain risk factors. The findings suggest that different carcinogens activate or inhibit specific pathways during cancer development and progression. These unique gene expression profiles should be taken into consideration when developing biomarkers for future use in prognostic or therapeutic applications.

Human telomerase reverse transcriptase expression in oral carcinogenesis--a preliminary report.

Human telomerase reverse transcriptase (hTERT), the catalytic subunit of telomerase, is strongly associated with telomerase activity implicated in cellular immortalization and tumorigenesis. In situ detection of hTERT will aid in determining the localization of telomerase positive cells. The aim of this study was to detect hTERT protein expression in multistep oral carcinogenesis using paraffin embedded tissue samples, and to study the relationship of hTERT expression with different histological stages in oral carcinogenesis. Normal (n = 4), hyperplastic (n = 4), dysplastic (n = 4) and neoplastic (n = 10) oral epithelia representing different histological stages in oral carcinogenesis were included in the study. hTERT protein detection was done by immunohistochemistry (IHC) technique. Nuclear staining intensities were noted and the hTERT-labelling index was determined. Dysplastic and neoplastic oral epithelia showed an increased percentage of hTERT positive cells (Grade 4: > 50% positive staining nuclei) with intense staining in the basal, parabasal and superficial layers of the epithelia, unlike normal oral mucosa which showed intense staining only in the basal and parabasal cell layers, which are the normal proliferative progenitor compartments. hTERT protein expression was elevated with the corresponding advancement of the histological stages of oral carcinogenesis, from normal to hyperplasia to dysplasia to carcinoma. There seems to be an upregulation of hTERT protein expression during the progression of oral cancer, therefore, this may indicate the feasibility of IHC detection of hTERT protein in oral carcinogenesis as a potential diagnostic or prognostic marker.

Do natural DNA triple-helical structures occur and function in vivo?

Formation of natural intramolecular triple-helical structures of DNA is still an intriguing research topic in view of the possible involvement of these structures in biological processes. The biochemical and biophysical properties of DNA triplex structures have been extensively studied, and experimental data show that H-DNA is likely to form in vivo and may regulate the expression of various genes. However, direct and unambiguous evidence of the possible biological roles of these structures is yet elusive. This review focuses on the basic facts that are in favor of, or against, the hypothesis of the presence and function of natural DNA triple-helical structures in vivo, and outlines the different methods and probes that have been used to support these facts.