ABSTRACT
Background: Telomerase is a ribonucleoproteins enzyme responsible for the maintenance of telomere length. Human telomerase reverse transcriptase [hTERT] is a major component of the catalytic subunit of telomerase enzymes and is expressed in cells that have telomerase activity but is not expressed in normal somatic cells. Based on the specific expression of hTERT in most cancer cells, it can be considered as a factor in the distinction between cancer cells and normal cells. It seems that inhibiting the expression of hTERT has been presented as a therapeutic approach in inhibiting the activity of telomerase. One of the special tools for inhibiting genes is the use of small interfering RNA [siRNAs]. The purpose of this study was to investigate the effect of hTERT gene on the cell viability and cell cycle in gastric cancer cells.
Materials and methods: In this study, human cancer cells, adenocarcinoma gastric cell line [AGS] were cultured in RPMI 1640 medium [Roswell Park Memorial Institute] containing 10 Percent FBS [Fetal Bovine Serum] and 1 Percent penicillin/streptomycin antibiotics. The suppression of the hTERT gene was accomplished by FlexiTube siRNA. The repression effect of hTERT gene was investigated on cell viability by MTT assay [3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide] with ELISA [Enzyme Linked Immunosorbent Assay] reader at 570 nm, and cell cycle performed by flow cytometry and DAPI [4', 6-diamidino-2-phenylindole] staining.
Results: The effect of hTERT siRNA on the cell viability by MTT assay showed time dependent cell viability of AGS cell line upon treatment and increasing the exposure time to 48 hours for that concentration decreased AGS cell [p = 0.02]. Analysis of flow cytometry also showed increased number of cells in G1 phase and decreased the number of cells in S phase, and induced apoptosis via decreasing the level of hTERT expression.
Conclusion: The significant downregulation in hTERT mRNA after 48 hours of hTERT siRNA treatment inhibited the cell viability of AGS cells and cell cycle arrest
ABSTRACT
Enterotoxigenic Escherichia coli [ETEC] is the most important bacterial cause of watery travelers' diarrhea in developing countries. Watery diarrhea is can cause serious life-threatening dehydration. ETEC was caused diarrhea by the secretion of two heat-labile enterotoxins [LTs] and the heat-stable enterotoxins [STs] which increase intestinal secretion. Routine laboratory methods are not appropriate to detect ETEC and other diarrheagenic E. coli pathotypes. The molecular techniques such as PCR are rapid and accurate methods that have been developed for detection of ETEC. We were recognized ETEC by PCR on lt and st genes from E. coli isolates from patients with diarrhea collected from selected Tehran educational hospitals. The E. coli isolates were collected from total 140 patients with diarrhea and 110 patients without diarrhea using culture and IMViC test. DNA was extracted by boiling method and the presence of the uidA, lt and st genes was detected by PCR. Among 140 E. coli isolates from diarrheal stools 5 [3.6%] isolates were positive for, just lt gene, 3 [2.1%] co-amplified for both lt/st and 1 [0.7%] was positive for just the st gene which were considered as ETEC. In the E. coli isolates from non-diarrheal control samples just one [0.9%] isolate was positive for both lt and st genes. The results showed that the ETEC as a significant cause of diarrhea, usually ignored by laboratories using traditional methods. Sometimes the ETEC causes severe diarrhea and can threaten for patient's life. Thus a rapid diagnostic test such as PCR can be very helpful in the treatment of patients
ABSTRACT
Background: Several systems of pain modulation in the central nervous system modulated the responses to painful stimuli in stressful and excitement situations. Stimulation of the hypothalamus induces analgesia through information relay to the brain stem including Rostral- Ventromedial medulla. The Rostral-Ventromedial medulla as output gate of the brain stem medulated pain through neurons in the dorsal horn. This pain modulation in central nerous system in various psychological conditions was based on existing of different neural groups and the special connections between them. These neurons cause pain modulation. The functional relationship between activation of one group of them and increasing pain and activation of another group and reduction of pain has been observed. In this review, it is discussed about the role of different neural groups of rostral-ventromedial medulla in pain modulation.
Conclusion: The Rostral-Ventromedial medulla has a major role in modulating pain and higher centers of the brain by altering the activity of the special groups of neurons cause to induce inhibition or facilitate pain in different stress and emotional conditions.
ABSTRACT
Background: Different processing methods are being used to improve the quality of hematopoietic stem cell transplantation. Using hydroxyethyl starch, simple centrifugation and Sepax automation, this study was aimed to compare these three conventional methods.
Material and Methods: 90 cord blood samples were taken and processed by hydroxyethyl starch, simple centrifugation and Sepax automation methods. Then they were subjected to total nucleated cell [TNC] counting and CD34 positive counting as well as colony assay. Finally, all data were analyzed using one-way analysis of variance [ANOVA] and ps less than 0.05 were considered statistically significant.
Results: The TNC recoveries in hydroxyethyl starch, simple centrifugation and Sepax automation methods were 76%, 71% and 80%, respectively [p> 0.05]. The CD34+ cell recoveries in the Sepax automation and in the other two methods were 91% and 85%, respectively [p> 0.05]. Also, the colony assay recoveries were not significantly different among the three methods [p> 0.05].
Conclusion: No significant difference was seen in TNC number, CD34 positive counting and colony formation among the three different methods.
ABSTRACT
PURPOSE: Breast cancer is the most common malignancy of women worldwide. Radiotherapy consists of a vital element in the treatment of breast cancer but relative side effects and different radioactive responses are limiting factors for a successful treatment. Doxorubicin has been used to treat cancers for over 30 years and is considered as the most effective drug in the treatment of breast cancer. There are also many chronic side effects that limit the amount of doxorubicin that can be administered. The combined radio-drug treatment, with low doses, can be an approach for reducing side effects from single modality treatments instead of suitable cure rates. METHODS: We have studied the effect of 1, 1.5, and 2 Gy doses of 9 MV X-rays along with 1 microM doxorubicin on inducing cell death, apoptosis and also p53 and PTEN gene expression in T47D and SKBR3 breast cancer cells. RESULTS: Doxorubicin treatment resulted in upregulation of radiation-induced levels of p53 and downregulation of PTEN at 1 and 1.5 Gy in T47D breast cancer cells, as well as downregulation of p53 mRNA level of expression and upregulation of PTEN mRNA level of expression in SKBR3 breast cancer cell line. In addition, doxorubicin in combination with radiation decreased the viability of breast cancer cell lines in the both cell lines. CONCLUSION: Low doses of doxorubicin, with least cell toxicity, may be an effective treatment for breast cancer when used in conjunction with ionizing radiation.