Comparison of Cellular Death Pathways after mTHPC-mediated Photodynamic Therapy (PDT) in Five Human Cancer Cell Lines.

One of the most promising photosensitizers (PS) used in photodynamic therapy (PDT) is the porphyrin derivative 5,10,15,20-tetra(m-hydroxyphenyl)chlorin (mTHPC, temoporfin), marketed in Europe under the trade name Foscan®. A set of five human cancer cell lines from head and neck and other PDT-relevant tissues was used to investigate oxidative stress and underlying cell death mechanisms of mTHPC-mediated PDT in vitro. Cells were treated with mTHPC in equitoxic concentrations and illuminated with light doses of 1.8-7.0 J/cm2 and harvested immediately, 6, 24, or 48 h post illumination for analyses. Our results confirm the induction of oxidative stress after mTHPC-based PDT by detecting a total loss of mitochondrial membrane potential (Δψm) and increased formation of ROS. However, lipid peroxidation (LPO) and loss of cell membrane integrity play only a minor role in cell death in most cell lines. Based on our results, apoptosis is the predominant death mechanism following mTHPC-mediated PDT. Autophagy can occur in parallel to apoptosis or the former can be dominant first, yet ultimately leading to autophagy-associated apoptosis. The death of the cells is in some cases accompanied by DNA fragmentation and a G2/M phase arrest. In general, the overall phototoxic effects and the concentrations as well as the time to establish these effects varies between cell lines, suggesting that the cancer cells are not all dying by one defined mechanism, but rather succumb to an individual interplay of different cell death mechanisms. Besides the evaluation of the underlying cell death mechanisms, we focused on the comparison of results in a set of five identically treated cell lines in this study. Although cells were treated under equitoxic conditions and PDT acts via a rather unspecific ROS formation, very heterogeneous results were obtained with different cell lines. This study shows that general conclusions after PDT in vitro require testing on several cell lines to be reliable, which has too often been ignored in the past.

Latencies to first typical generalized spike-wave discharge in idiopathic generalized epilepsies during video-EEG monitoring.

To assess latencies to the first typical generalized spike-wave discharge (GSWD) and clinically manifest seizure during long-term video-EEG monitoring (VEM) in patients with idiopathic generalized epilepsy (IGE). This is a retrospective analysis of continuous long-term VEM of 39 patients (25 women; mean age, 28.7 years). Mean duration of VEM was 3 days (1-11 days). Latencies from start of VEM to the first appearance of GSWD and the first clinically manifest seizure were analyzed for IGE subsyndrome. Overall, mean latency from the beginning of VEM to the first typical GSWD was 853 minutes (range, 3-7,305 minutes). In 38.5% of the patients, the first typical GSWD occurred during the first hour of VEM and in 87.2% during the first day. Latencies were significantly shorter in juvenile absence epilepsy than in juvenile myoclonic epilepsy, epilepsy with generalized tonic-clonic seizures only, and IGE not further classified (P = 0.001). In 38.5% of the patients, clinically manifest seizures were recorded. Overall, mean latency to the first seizure was 1,984 minutes (range, 3-8,123 minutes). There were no significant differences in latencies to the first seizure between IGE syndromes. One day of VEM is sufficient for classification as IGE in the majority of patients. Patients with juvenile absence epilepsy had particularly low latencies to the appearance of the first typical GSWD. There is, however, a group of patients (12.8% in our sample) requiring a prolonged VEM period to achieve sufficient electroclinical evidence for syndromatic classification.

Early detection of behavioral side effects of antiepileptic treatment using handheld computers.

OBJECTIVE: Treatment-emergent side effects are frequent events, particularly during the uptitration of antiepileptic drugs. So far, monitoring of such adverse events in outpatients has often been limited to intervals of weeks or months. We here report the application of a new device for temporally fine-grained assessment of objective well-being and cognitive performance using personal digital assistants (PDAs). METHODS: Twenty adult patients with epilepsy participated in this pilot study. Ten received add-on treatment with levetiracetam. Ten patients with constant medication served as a control group. Differences between groups with respect to self-rated cognitive condition, psychophysical condition, aggressiveness, and cognitive test performance in a concentration test assessed three times daily (morning, early afternoon, and evening), over the course of 6 days, were analyzed. RESULTS: Levetiracetam-treated patients manifested an early augmentation of self-rated aggressiveness, which increased in intensity over the course of days. Aggressiveness reached a maximum in the early afternoon across days. There were no major changes in cognitive performance, except for an increase in morning performance in the control group. CONCLUSIONS: This study demonstrates the feasibility of a new method of ambulatory assessment of behavioral and cognitive data during titration of antiepileptic drugs. Significant changes in aggressiveness under add-on treatment with levetiracetam were found to be dependent on the time of assessment during the day. These results suggest that PDA-based ambulatory monitoring of patients with epilepsy may be a promising tool for early detection of drug-related side effects and, thus, may constitute a significant improvement in patient care.