Photodynamic agents, due to their selective uptake by tumor cells and photon-dependent selective activation, have immense implications for cancer treatment. The present study provided direct evidence that the photon activation of chloro-aluminum phthalocyanine sulphonate (AlPcS4) in the presence of extracellular Ca2+ caused a rapid increase followed by a sustained increase in intracellular concentration of calcium ion ([Ca2+]i) in a small cell lung carcinoma (SCLC) cell line, SBC-3. The [Ca2+]i increase by photodynamic stimulation was completely inhibited by the removal of extracellular Ca2+ and reintroduction of extracellular Ca2+ immediately led to a rapid elevation of [Ca2+]i. However, the increase was not inhibited by application of Ni2+, nifedipine, or SKandF 96365, a receptor-mediated and voltage-dependent Ca2+ entry blocker. The photosensitizer AlPcS4 alone or light alone (4 min) had no effect on [Ca2+]i. Cytotoxicity examination by trypan blue exclusion test, however, suggested photodynamic stimulation-induced cell injury which was observed in both the presence and the absence of extracellular Ca2+. These results indicate that [Ca2+]i increase may not be mandatory for photodynamic stimulation-induced cell injury. Whether [Ca2+]i increase can accelerate, at least in part, cell death under the physiological condition, whether the mechanism(s) of cell death can be different in the presence and the absence of extracellular Ca2+, and whether [Ca2+]i increase can be totally unrelated to cell death await further work

For detecting Borna disease virus (BDV) genomic stranded RNA, single-tube reverse transcription-polymerase chain reaction (St RT-PCR) was developed to equal the sensitivity of RT-nested PCR but with reduced risk of contamination. BDV-genomic stranded RNA was synthesized in vitro using plasmid cDNA of BDV p24 region as a template and RNA was also extracted from BDV-persistently infected MDCK (MDCK/BDV) cells. Both RNAs were amplified by St RT-PCR in which a single round of RT and a single round of PCR were performed in the same tube. Ten copies of synthesized RNA could be amplified by St RT-PCR, indicating that St RT-PCR method is as sensitive as the ordinary RT-nested PCR method. Furthermore, this method was applied to quantify the exact copy number of genomic RNA in MDCK/BDV cells. Signals were obtained from the samples containing more than 1 pg total cellular RNA. From the results, approximately 100 copies of BDV genomic RNA exist in one MDCK/BDV cell. BDV genomic RNA from the in vivo RNA samples using St RT-PCR, indicating this method is applicable for the epidemiological study of BDV without contamination