Comparison of myocardial cell survival 2 h and 24 h after extracellular talaporfin sodium-induced photodynamic reaction.

BACKGROUND: We have proposed an application of photodynamic reaction for less-heated myocardial ablation which employs talaporfin sodium. Intracellular photodynamic reactions with ongoing uptake have the ability to induce apoptosis over time, raising the possibility of extending the lesion depth. The objective of this study was to understand how, in myocardial cells, the late cell survival levels change by incubation time with talaporfin sodium, and what dependence talaporfin sodium uptake has on the duration of incubation with talaporfin sodium in vitro. METHODS: Rat myocardial cells were incubated with talaporfin sodium for 5-360 min and intracellular concentrations measured using a fluorescence micro-plate reader after wash. Cell survival was measured using a water-soluble tetrazolium assay at 2 and 24 h after a photodynamic reaction using a red diode laser of 660 nm, following 15-180 min of incubation with talaporfin sodium. Cells were stained with Hoechst 33342 to observe nuclear changes. RESULTS: Intracellular talaporfin sodium concentration increased with incubation time, with a marked increase between 0 and 60 min. Cell survival at 24 h decreased by 20% when the duration of incubation with talaporfin sodium was extended from 15 to 30 min. Following incubation time of 30-180 min with talaporfin sodium, cell survival was decreased by approximately 30% between measurements at 2 and 24 h. The intracellular talaporfin sodium concentration that induced higher levels of late cell death with cell nuclei fragmentation in these cells was approximately 0.2 µg/mL. CONCLUSION: We obtained the characteristics of late cell death occurrence and talaporfin sodium uptake to myocardial cell with various incubation times with talaporfin sodium.

Relationship between facial asymmetry and masseter reflex activity.

PURPOSE: In this study, we evaluated the tonic vibration reflex (TVR) of the masseter muscles in patients with facial asymmetry. SUBJECTS AND METHODS: The study was conducted with 10 volunteers without facial asymmetry and 12 orthognathic patients with facial asymmetry. Subjects were seated in a chair and held a stimulator composed of an electric motor and an acrylic bite block between the upper and lower dentitions at facial midline, to elicit TVR. Electromyographic activity was recorded using a pair of silver electrodes affixed bilaterally with adhesive tape to the skin over the superficial masseter. The amount of mandibular deviation was measured on the frontal cephalogram. The reflex response was evaluated with the following: TVR index (%) = integral TVR x 100/ integral maximum voluntary contraction (MVC), and with the TVR ratio: integral TVR on the high MVC side/ integral TVR on the low MVC side. RESULTS: In the patient group, the average TVR index on the deviated side was significantly higher than that on the nondeviated side. In all subjects, including the control and patient groups, a negative correlation between the amount of mandibular deviation and the side-to-side difference in TVR index was seen (r = -0.536, P <.05, n = 22). In addition, patients with a lower MVC on the deviated side than on the nondeviated side showed a significantly higher TVR ratio than did the control group. CONCLUSIONS: These results suggest that the difference between the right and left reflex responses elicited by TVR might be related to frontal craniofacial morphology.