, Kang-Sup Shim, Sung-Sook Kim, Heasoo Koo, Eung-Bum Park Apoptosis is a specific mode of cell death recognized by a characteristic pattern of morphological, biochemical, and molecular changes, There are several methods of detection of apoptosis. Morphological changes involve a characteristic pattern of chromation and cytoplasm. The landmark of apoptosis is endonucleolysis, with nuclear DNA initially degraded at the linker sections to fragments equivalent to single and multiple nucleosomes. Detection of DNA fragments is situ using the terminal deoxyribonucleotidyl transferase(TDT)-mediated dUTP-digoxigenin nick end labeling (TUNEL) assay is increasingly applied to investigate apoptosis. We studied the detection method of apoptosis morphologically and by using TUNEL assay and examined the correlation of p53 expression and apoptosis.
Forty-five cases of colorectal cancer were selected. The number of apoptotic bodies was expressed as a number per 100 cancer cells. The TUNEL assay was performed with in situ Apoptag kit®.
The mean number of the apoptotic bodies was 2.28 in the patients who survived over 5 years after curative resection and 3.55 in the patients who died within 5 years(p=0.001). There was a relationship between the number of apoptotic bodies which were measured by morphologic study and the results which were measured by TUNEL assay. There was no relationship between p53 expression and apoptosis.
These results suggest that the frequency of apoptotic bodies may be a prognostic factor for colorectal cancer and apoptosis could be measured by morphological study without special study.
, Heasoo Koo Paclitaxel(Taxol) si a chemotherapeutic agent with potent microtubule stabilizing activities that arrests cell cycle in G2-M. Since D2-m is the most radiosensitive phase of the cell cycle, paclitaxel has potential as a cell cycle-specific radiosensitizer. This study was designed to investigate the effects of paclitaxel to radiotoxicity in normal rat liver.
A single intraperitoneal infusion of paclitaxel(10mg/kg), and a single irradiation(8Gy, x-ray) to the whole abdomen, and combination of irradiation(8Gy,x-ray)24 hours after paclitaxel infusion were done in Sprague-Dawley rats. The incidence of mitosis, apoptosis and parenchymal changes of the liver were evaluated at 6 hours, 24 hours, 3 and 5 days, respectively.
Paclitaxel and irradiation significantly increased mitosis at 6 hours and apoptosis was increased by irradiation at 6 and 24 hours. Increased numbers of apoptosis at 3 days by paclitaxel alone was not significantly different from control. Combination of paclitaxel and irradiation showed significantly increased numbers of mitosis and apoptosis at 6 hours. The degree of necrosis of hepatocyte was not significantly different between 3 groups.
Since the incidence of mitosis, apoptosis and hepatocyte necrosis were not increased by paclitaxel infusion 24 hours before irradiation, paclitaxel did not show radiosensitizing effect in this experimental condition. Studies with conditions similar to clinical situation will be the next stop to define the radiosensitizing effects of paclitaxel.
Reactive oxygen species (ROS) such as hydrogen peroxide, superoxide anion and hydroky radicals are produced in various physiologic and pathologic conditions and involved in many cellular processes as proliferation, differentiation and apoptosis. Studies investigating the role of ROS in various cellular behaviors especially in proliferation and apoptosis have been widely conducted in many cell types but the role of ROS in nontransformed human hepatocyte differentiation has not been investigated yet. thus we were going to elucidate the roleof ROS on human hepatocyte differentiaiton using sodium butyrate (SB) induced hepatocyte differentiation model of our own establishment.
Intracellular ROS and apoptotic cell death were monitored by flowcytometry using peroxide sensitive probe (Dicholorofluorscein diacetate) and Annexin V/Propidium iodide, respectively. Urea nitrogen in culture media was measured by colorimetric methods. Ornithine transcarbamylase(OTC) and albumin trasncription was evaluated by RT-PCR.
Intracellular ROS production was increased by SB. SB induced urea production was significantly decreased with antioxidant treatment (p<0.05) and SB induced OTC and albumin transcription were also attenuated with antioxidant treatment. SB induced increase in apoptosiswas significantly inhibited by antioxidant treatment (p<0.05).
ROS produced during the process of sodium butyrate induced human hepatocyte differentiation auguments hepatoctye differentiation and apoptosis.
Acetaminophen is a mild analgesic and antipyretic agent that is safe and effective when taken in therapeutic doses. Ingestion of overdoses, however, may lead to acute liver failure accompanied by centrilobular degeneration and necrosis. The toxicity of acetaminophen is generally thought to be caused by direct interaction of its reactive metabolites with cellular macromolecules. Cell death, defined as an irreversible loss of vital cellular function and structure, can occur by either necrosis or apoptosis. Until recently, investigation into liver cell death has focused on cell necrosis although it is now appreciated that both apoptosis and necrosis may contribute to liver cell death. The present study examined cultured NCTC-1469 cells for LDH release and DNA laddering and their association with cell death. NCTC-1469 cells were cultured in NCTC-135 medium containing 10% horse serum for 72hr, and changed medium to fresh medium containing acetaminophen(from 0,5mM to 5mM). Cell viability was examined by MTT method and cell necrosis was assessed lactate dehydrogenase leakage. Genomic DNA fragmentation was assessed qualitatively by 1.5% agarose gel electrophoresis. Acetaminophen decreased MTT levels(p<0.05) and increased release of LDH(p<0.05) in dose-dependendent manner. Agarose gel electrophoresis revealed a "ladder" of DNA fragments in all acetaminophen concentration. Cell viability strongly correlated with cell necrosis(r2=0.946). These results show that acetaminophen induced both necrosis and apoptosis in NCTC-1469 cells and cell death mainly attributed to apoptosis.
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