Effects of Nigella sativa seeds and certain species of fungi extracts on number and activation of dural mast cells in rats

In this study, we aimed to investigate the effects of Nigella sativa seeds and certain species of fungi extracts on the number and degranulation states of dural mast cells in rats. Rats were fed ad libitum with normal tap water or tap water with extract of N. sativa seed, Ramaria condensata, Lactarius salmonicolor, Lactarius piperatus, and Tricholoma terreum for 3 days. Mast cells in dura mater were counted and evaluated in terms of granulation and degranulation states. Compound 48/80, a mast cell degranulating agent, and T. terreum significantly increased the percent of degranulated mast cells in dura mater, respectively (p < 0.01 and p < 0.05). Moreover, T. terreum causes a significant increase in the total number of mast cells (p < 0.05). N. sativa significantly inhibited mast cell degranulation induced by both the compound 48/80 and T. terreum (p < 0.05), and significantly decreased the mast cell numbers increased by T. terreum (p < 0.05). Our results suggested that T. terreum following ingestion can contribute to headaches like migraine via dural mast cell degranulation and N. sativa may be able to exert analgesic and anti-inflammatory effects by stabilizing dural mast cells. However, investigation is needed to determine the ingredients of N. sativa that may be responsible for these beneficial effects.

Hunting for origins of migraine pain: cluster analysis of spontaneous and capsaicin-induced firing in meningeal trigeminal nerve fibers

Trigeminal nerves in meninges are implicated in generation of nociceptive firing underlying migraine pain. However, the neurochemical mechanisms of nociceptive firing in meningeal trigeminal nerves are little understood. In this study, using suction electrode recordings from peripheral branches of the trigeminal nerve in isolated rat meninges, we analyzed spontaneous and capsaicin-induced orthodromic spiking activity. In control, biphasic single spikes with variable amplitude and shapes were observed. Application of the transient receptor potential vanilloid 1 (TRPV1) agonist capsaicin to meninges dramatically increased firing whereas the amplitudes and shapes of spikes remained essentially unchanged. This effect was antagonized by the specific TRPV1 antagonist capsazepine. Using the clustering approach, several groups of uniform spikes (clusters) were identified. The clustering approach combined with capsaicin application allowed us to detect and to distinguish "responder" (65%) from "non-responder" clusters (35%). Notably, responders fired spikes at frequencies exceeding 10 Hz, high enough to provide postsynaptic temporal summation of excitation at brainstem and spinal cord level. Almost all spikes were suppressed by tetrodotoxin (TTX) suggesting an involvement of the TTX-sensitive sodium channels in nociceptive signaling at the peripheral branches of trigeminal neurons. Our analysis also identified transient (desensitizing) and long-lasting (slowly desensitizing) responses to the continuous application of capsaicin. Thus, the persistent activation of nociceptors in capsaicin-sensitive nerve fibers shown here may be involved in trigeminal pain signaling and plasticity along with the release of migraine-related neuropeptides from TRPV1 positive neurons. Furthermore, cluster analysis could be widely used to characterize the temporal and neurochemical profiles of other pain transducers likely implicated in migraine.

The effect of ceramic restoration shade and thickness on the polymerization of light- and dual-cure resin cements

OBJECTIVES

Inadequately polymerized resin cements may negatively affect the clinical performance of cemented all-ceramic restorations. The purpose of this in vitro study was to evaluate the effect of ceramic thickness and shade on the microhardness of various light-cured (LC) and dual-cured (DC) resin cements. The amount of light transmission through the restoration was also evaluated to correlate the results.

METHODS

Three different brands of resin cements (Appeal/Ivoclar; Calibra/Dentsply; Nexus 2/Kerr) were used in LC and DC forms to prepare disk-shaped samples (0.5-mm thickness × 5-mm diameter) (n=15). Study group samples were light-cured for 40 seconds (Flashlite 1401/Discus Dental) through four shades (ETC1, ETC2, ETC3, ETC4) and four thicknesses (1 mm, 2 mm, 3 mm, 4 mm) of all-ceramic ingot discs (IPS Empress Esthetic/Ivoclar). Control samples were directly cured without the presence of ceramic. The light transmission through various shades and thicknesses of ceramics was measured using a hand-held radiometer (Demetron, Kerr). Vickers microhardness measurements were performed (Micromet/Buehler) at 24 hours following dark storage in 37°C water. Correlation between ceramic shade, thickness, and light intensity readings (mW/cm2) with respect to microhardness was statistically evaluated using analysis of variance (p=0.05).

RESULTS

Ceramic thickness of 3 mm and/or above significantly decreased the microhardness values in all LC and DC groups (p<0.0001). Ceramic shade had a significant effect only on Calibra in both LC and DC groups (p<0.0001). Microhardness values of LC groups were significantly lower than DC groups (p<0.0001). Control groups had significantly higher hardness values in all cement groups (p<0.0001). There was a significant correlation between the amount of light transmitted and hardness (p=0.000).

CONCLUSION

The ceramic thickness has a more intense effect on polymerization compared to the ceramic shade. Overlying ceramic thickness of 3 mm and above was found to adversely affect the polymerization of LC and DC resin cements and therefore a 3-mm thickness was considered the critical threshold.

Multielectrode array for simultaneous recording of glucose, oxygen and electrocorticography from cerebral cortex in experimental focal epilepsy

Delineating epileptic tissue before and during surgery is still a major problem. Electroencephalography (EEG), electrocorticography (ECoG), and magnetoencephalography (MEG) evaluations may not always correlate with outcome. Metabolic mapping, i.e. positron emission tomography (PET) or single photon emission tomography (SPECT), is not practical or not sensitive--both spatial and temporal--enough for use in neurosurgery. Amperometric electrochemical electrodes for recording oxygen and glucose from nervous tissue are developed and tested in rat experimental focal penicillin epilepsy model. With a three-by-three array of glucose electrodes, epileptic focus is mapped. Simultaneous recordings of ECoG, oxygen and glucose levels performed. During seizure, extracellular glucose level showed a biphasic response pattern while oxygen level decreased slightly. It has been concluded that such a combined subdural grid recording might help before and during surgery. This method can be used in ischemia and such experimental metabolic studies.