Activity and expression of human telomerase in normal and malignant cells in gastric and colon cancer patients.

BACKGROUND: The reactivation of telomerase is believed to play an important role in immortalization and carcinogenesis. OBJECTIVE: To investigate the expression of three components of the telomerase complex (hTR, hTERT and TP1), along with telomerase activity in malignant and normal cells. METHODS: Cells were isolated from gastric and colon cancer, and from normal mucosa from the stomach and colon of participating patients. Expression of hTERT, hTR and TP1 has been studied by the reverse transcriptase polymerase chain reaction (PCR) technique. The telomerase repeat amplification protocol and PCR enzyme-linked immunosorbent assay were used for analysis of telomerase activity. RESULTS: All telomerase components were consistently expressed in colon and gastric cancer cells. Neoplastic RNA produced consistently very strong amplification signals either for hTR, hTERT or TP1. The expression of hTR was observed in RNA isolated from all normal mucosa samples and from peripheral blood lymphocytes. The expression of TP1 and hTERT has been found in the majority of normal cells; however, the amplification signals produced were usually much weaker than in malignant cells. The limiting dilution experiments indicated that the cancer cells have at least 100-fold higher telomerase activity and at least 25-fold higher TP1 and hTERT expression in comparison to normal cells. CONCLUSIONS: It can be concluded that all the cancer cells tested have higher telomerase expression and activity than normal cells. Therefore, telomerase can be a good cancer marker, provided that quantitative analysis is carried out.

[Prevalence of TT virus in patients with hepatitis B,C and hepatitis of unknown etiology]. / Wystepowanie wirusa TT u chorych z zapaleniem watroby typu B, C i o nieustalonej etiologii.

Discovery of TT virus in 1997 gave raise to intensive subsequent studies to learn about its structure, features and, what is the most important, about its role in pathogenesis of liver disease. The aim of the work was to analyze prevalence of TTV DNA in patients with diagnosed hepatitis B, C, that of unknown etiology and in healthy blood donors as well. Additionally the divergence of TTV sequence was estimated in selected cases. TTV DNA was detected by PCR technique using specific oligonucleotide primers for coding regions. TT virus has been detected in 25.6% (32/125) HBsAg positive patients and in 23.9% (51/213) HCV infected patients. In healthy blood donors the frequency of TTV was 24.3% (34/140) similarly to that found in HCV and HBV infected patients. The frequency of TTV DNA among patients with hepatitis of unknown etiology was 9.1%. This result was statistically significant lower than in the other groups. When detected sequences have been compared to these from NCBI base the homology result was 71% to 95%, and among different patients and groups of patients identity was 46% to 73%. On the basis of the obtained results it can be concluded that it is very unlikely that TTV coinfection plays any significant role in HCV or HBV infection. The hypothetical role of TTV infection in the etiopathogenesis of cryptogenic chronic hepatitis has not been confirmed. The results obtained in the small group of patients with hepatitis of unknown etiology are not conclusive and should be taken with some precaution. The final conclusion is the TTV coinfection does not contribute to the liver pathology. The divergence of TTV sequences may explain the various frequency of TTV viremia reported by other authors.

MSRV pol sequence copy number as a potential marker of multiple sclerosis.

Multiple sclerosis (MS) is a neurological disease in which demyelination in the brain and spinal cord is observed. The causal influence of bacterial/viral infections and genetic/immune factors in the etiology of multiple sclerosis is suggested. Multiple sclerosis-related retrovirus (MSRV) is one of the potential agents, which can lead to development of the disease. The aim of cytogenetic studies was assessment of MSRV pol sequence copy number in patients with MS compared to normal individuals. Cytogenetic slides with interphase nuclei and extended chromatin fibers were prepared from peripheral blood of 16 patients with MS and 10 healthy individuals. Fluorescence in situ hybridization (FISH) with biotinylated product of polymerase chain reaction was used in order to analyze MSRV pol sequence copy number in the examined material. Detection of MSRV pol probe was carried out by immunological reaction with avidin-fluorescein and biotinylated anti-avidin. MSRV pol sequence copy number was significantly greater in MS patients than in normal individuals. Using FISH technique to extended chromatin fibers, it was observed that MSRV pol exists as tandem repeats on various chromosomes. The increased number of MSRV pol sequence has been found on chromatin fibers of MS patients as compared to healthy controls.