Because adenosine trisphosphate (ATP) plays a pivotal role in causing inflammatory processes and pain, effects of ATP on dorsal root ganglion (DRG) has been extensively studied by electrophysiological methods. However, in the previous studies, satellite cells surrounding ganglion cells have no been studied. The present study aimed to reveal the effects of ATP on ganglion and satellite cells, to this end we observed intracellular Ca^<2+> ion concentration ([Ca^<2+>]_i) change in DRG which kept structural integrities. DRG were taken out from immature (E20D) and mature (8W) rats. The [Ca^<2+>]_i changes during ATP stimulation were analysed by a confocal microscope. In immature and mature DRG, both ganglion and satellite cells responded to ATP. The ATP-induced [Ca^<2+>]_i increase of ganglion cells was rapid, and the decline was slow, while the satellite cell responses were spike-like. Only 1-3% of ganglion cells showed ATP-induced [Ca^<2+>]_i changes, and about 40% of satellite cells responded. Based on the dependence of the response on presence of extracellular Ca^<2+> and the agonist stimulations, ganglion and satellite cells possessed P2X and/or P2Y. There were no significant differences on ganglion cell responses between immature and mature DRG. In immature satellite cells, the response was single-shot, while mature satellite cells showed oscillatory fluctuation. Present results indicate that population of ganglion cells responding to ATP was low. Previous studies might confuse responses of satellite cells and those of ganglion cells. Oscillatory fluctuations appeared in mature satellite cells indicated a change of intracellular signalling mechanism during postnatal development.
Purpose : The purpose of this study was to investigate changes in spatial learning and memory in rats after extraction of maxillary molar teeth by 8-arm radial maze test and measurements of numbers of TrkB mRNA positive cells in hippocampal pyramidal cells. Materials and Methods : Seventy-two male Wistar rats (7 weeks old) were divided into four groups for this study. In Group A, molar teeth were left intact. In Group B, maxillary first molar teeth were extracted. In Group C, maxillary first and second molar teeth were extracted. In Group D, maxillary first, second and third molar teeth were extracted. A series of spatial memory tasks were performed in an 8 -arm radial maze at 1, 4 and 7 weeks for all four groups. Following completion of this task period, levels of pyramidal cells and TrkB positive cells were observed. Results : At 7 weeks, the results showed that Groups B, C and D exhibited significant behavioral dysfunction compared to group A, yet behavioral dysfunction was more remarkable the greater the number of lost molar teeth. Group B, C and D also showed a significant decrease in the number of hippocampal pyramidal cells and TrkB positive cells in CA1, CA3 and CA4. Conclusions : In conclusion, since the effects of experimental tooth extractions in rats caused decreased amounts of TrkB mRNA positive cells in hippocampal pyramidal cells, spatial learning and memory were affected. As the number of teeth lost increased, higher brain function decreased.
Purpose : The aim of this study was to evaluate the effect of a palatal plate on taste by gustatory evoked potentials. Method : Seventeen healthy subjects were selected. An electrical stimulation was delivered to the taste buds area of the tongue (chorda tympani, glossopharyngeal nerve area), and the soft palate (greater petrosal nerve area). A palatal plate was used as an experimental conditions to simulate the denture. For the taste threshold, quality of judgment and Electroencephalogram (EEG), conditioned subjects wore a palatal plate, and control group subjects wore no plate. Results : At insertion of a palatal plate, taste threshold be come significantly higher in three nerve areas. By electrical stimulation, subjects were sorted into groups in which electrical taste was induced, and where only touch was induced. Taste quality of judgment change could not be seen between Controlled and Conditioned situations. In EEGs, three waves (P1, N1, P2) were observed when electrical taste was induced in the subjects. In either condition, there were no individual differences in latencies and amplitudes. Insertion of the palatal plate, didn't affect latencies. On the other hand, N1-P2 amplitude decreased significantly. Conclusion : Our investigation has shown this method to be a useful in objective evaluation of taste in denture patients.
Purpose : The aim of this study was to examine the relationship between occlusal interference positions and localizing EEG potential in each hemisphere. Methods : Eight healthy dentates were selected as subjects. Electromyograms (EMG) from the bilateral masseter and posterior temporal muscles and electroencephalograms (EEG) were simultaneously recorded and analyzed before and after mastication of kamaboko. Twelve sessions were carried out : the control (Cont), just after (JA), 1∿7 days later after wearing the interference (1∿7 DL), just after removing the interference (JAR) and 1∿2 days after removing the interference (1∿2 DLAR). Results : The peak of decreasing masticatory muscle activity during non-interfering side mastication appeared later and continued to decrease, compared to interfering side mastication. EMG coordination pattern was affected by restraint of masseter activity during the interfering side mastication, and by restraint of posterior temporal activity during non-interfering side mastication. After mastication, %α in EEG decreased, and %β significantly increased compared to before mastication. %β increased later during non-interfering side mastication. %α after mastication showed no significant change in either hemisphere. However %β after mastication were significantly higher in the left hemisphere than the right regardless of the mastication side. In addition, hemispheric differences of %β appeared later in non-interfering side mastication compared to interfering side mastication. Conclusion : The experimental occlusal interference affected the %β of the left hemisphere, and fluctuation of %β agreed with EMG appearance. It suggests that impulses from occlusal interference projected to hemisphere activity opposite to the interfering side.
Autopsy cases of tongue cancer in Japan were statistically analyzed. Autopsy cases were collected from the Annual of Pathological Autopsy Cases in Japan over the past five years (1997-2001). Tongue cancer was reported in 321 autopsy cases(M:241, F:79, Unknown: 1). The autopsy rate was 6.0% of 5,320 patients who died of tongue cancer in Japan. 103 of the autopsied patients (32.2%) were in their seventh decade, 74 (23.1%) were in their eighth decade, and 54 (16.9%) were in their sixth. Histologically, almost all the cases showed squamous cell carcinoma (96.8%). The cancer arose most frequently in the lateral borders (66.1%) of the tongue. Multiple primary cancers, affecting both the tongue and other organs, were found in 113 cases. The mean ages of only the autopsied cases of squamous cell carcinoma excluding the cases of multiple primary cancers were 63.8±10.1 (1997), 57.7±12.3 (1998), 65.4±13.6 (1999), 61.7±15.4 (2000) and 62.1±14.9 (2001) years old. However, the mean ages of multiple primary cancers, affecting both the tongue and the other organs, were 69.2±9.9 (1997), 70.5±11.2 (1998), 66.6±10.2 (1999), 68.2±11.6 (2000) and 69.9±15.5 (2001) years old. In cases of double cancers including tongue cancer, commonly occurring cancers were lung, liver, esophagus, thyroid and adrenal. Metastasis to other organs was frequently found in the tracheobronchus and lungs, liver, heart and aorta, bones, adrenals and thyroid. Metastasis to the lymph node was found in the cervix, lung hilum, periesophagus and peritrachea, left supraclavicula, and axilla. The most common cause of death was pulmonary infection.
We analyzed 25 cases of propofol(PPF) anesthesia using a laryngeal mask airway (LMA) in order to establish a method of safe outpatient anesthesia for the dental treatment of the handicapped. Subjects discussed here are gender, age, coexisting problems, medication, reasons for general anesthesia, dental treatments, the time needed to treat, general assessment, premedication, induction techniques, dosage of midazolam, dosage of PPF, the stability of airway management with LMA, infusion volume, body temperature under anesthesia, anesthesia period, period of time from stopping propofol till discharge, and states of patients after discharge. Results were that 1) airway management with LMA was secure in 76% of cases(19/25); 2) mean time from stopping propofol untill discharge was 70.8±16.3 minutes; 3) no problems occurred after discharge; 4) patient's helpers preferred outpatient anesthesia with short postoperative period of time. We conclude that 1) the airway management with LMA is non-invasive and reliable if gastric contents are removed; 2) PPF is suitable for outpatient anesthesia because fewer post-anesthetic problems occur than with sevoflurane; 3) anesthesia with FLMA and PPF is suitable for outpatients in dentistry not adjusted to admission.
This report describes a case of hyperplasia of the mandibular coronoid process treated by coronoidotomy. A 26-year-old man visited our clinic complaining of restricted mouth opening. Panoramic radiography revealed marked hyperplasia of the right mandibular coronoid process. Three-dimensional CT showed that the coronoid process touched the temporal surface of the zygomatic bone at the maximal mouth opening position. His maximum mouth opening range was 27mm. The coronoid process was amputated about 8mm in width, and mouth opening training was done for a year after the surgery. Although the coronoid process and mandibular ramus reunited, the maximum mouth opening range was maintained at 40mm 13 months after the surgery.