The ability of benzalkonium chloride to induce thermotolerance was examined in NIH3T3 cells. Benzalkonium chloride enhanced cytotoxicity as its concentration and administration period increased. The cell survival decreased to 50% of that in the non-treated group by 20min of treatment in 0.002% benzalkonium chloride. Thermotolerance developed during the culture after 20min of treatment with 0.002% benzalkonium chloride. Thermotolerance reached its peak at 15h after treatment and decreased subsequently. At 15h after treatment, the Do value at 45°C heating, a parameter of thermotolerance was 3.8-fold higher than that of the non-treated group. The thermotolerance induced by 0.002% benzalkonium chloride increased as its treatment period was prolonged. These findings suggested a relationship between thermotolerance induction and the cell membrane damage by benzalkonium chloride.
Direct antitumor effect of cepharanthin (CEP) and the combined effect with adriamycin (ADR), as well as the effect of CEP against body weight loss caused by treatment of ADR were evaluated using ICR mice bearing Ehrlich ascites tumor. Single administration of CEP reduced tumor growth compared to that of the untreated control, but not significantly. However, multiple administration of CEP reduced the tumor growth significantly compared to that of the untreated control (p < 0.001). Simultaneous administration of intratumoral CEP and intravenous ADR reduced the tumor growth significantly compared to that of ADR alone (p < 0.05). Further, CEP restored body weight loss caused by the treatment of ADR (p < 0.01). These findings indicate that the combined administration of CEP and ADR may be effective in cancer treatment.
A phantom has previously been developed containing carrageenan, agarose and gadolinium chloride (called CAG phantom) for MRI with 1.5 T. T(1) and T(2) relaxation times of this phantom are independently changeable by varying concentrations of relaxation-time modifiers to simulate relaxation times of the various types of human tissues. The CAG phantom has a T(1) value of 202-1904 ms and a T(2) value of 38-423 ms, when the GdCl(3) concentration is varied from 0-140 micromol/kg and the agarose concentration is varied from 0-1.6%. A new phantom has now been developed (called CAGN phantom), made by adding an electric conductive agent, NaCl, to the CAG phantom for use in the areas of MRI and hyperthermia research. Dielectric properties of the CAGN phantom were measured and the results of experiments were expressed by the Cole-Cole equation in the frequency range of 5-130 MHz. The relationship between the conductivity of the CAGN phantom and the concentration of NaCl was expressed by a linear function in the frequency range of 1-130 MHz. The linear function involves a parameter of frequency and, when the frequency is 10 MHz, the conductivity of the CAGN phantom can be changed from 0.27-1.26 Sm(-1) by increasing the NaCl concentration from 0-0.7%. The CAGN phantom developed can be employed in basic experiments for non-invasive temperature measurement using MRI and as a loading phantom for MRI with up to 3 T.
Mice of dd strain were exposed repeatedly to 300 R at one week intervals to their death. Pretreatment of glutathione (GSH), cysteamine and aminoethylisothiuronium (AET) showed radioprotective effect from radio-induced killing of animals. GSH was given at 30 min., 3 hours, and 6 hours prior to irradiation and a clear radioprotective effect was observed when the drug was given at 30 min. or 3 hours before irradiation. Drug administration at 6 hours before exposure was not so effective. Posttreatment of these agents showed no effect. GSH of 30 mg demonstrated most effective protection among the doses tested. AET of 3 mg or 6 mg and mercaptoethylamine (MEA) of 2 mg suggested radioprotective effects, and AET of 6 mg was the most effective among the SH compounds tested. (auth)
Using a pEYFP-Nuc vector, which contains nucleic acid sequences of a nuclear localization signal, we established a Jurkat-YN cell line that expressed enhanced yellow fluorescent protein (EYFP) in the nucleus. We observed three-dimensional and time-lapse changes in nuclear morphology of Jurkat-YN cells during Fas-induced apoptosis using a confocal laser scanning microscope. The nuclear forms visualized by EYFP were almost equal in quality to those visualized by SYTO59, a nucleic acid stain for living cells. Three-dimensional deformities in the nuclear form were observed during apoptosis before chromatin condensation became apparent, indicating these deformities are characteristic morphological changes of the early stage of apoptosis. In conclusion, the pEYFP-Nuc vector is a useful tool in the time-lapse observation of nuclear morphology of living cells during apoptosis.
