This study proposes a new method for a prognostic analysis on the course of diseases. This method aims to separate, among same disease population, several prognostic groups showing different temporal patterns in the course of the disease and evaluate the influence of prognostic factors separately for each group. To do this, we develop a new temporal distribution that we call multiple component Weibull distribution, which is given by a linear combination of Weibull distributions with different shape and scale parameters. This method is applied to the prognostic analysis of cardiac death of acute myocardial infarction (AMI) during hospitalization. The subjects are the first year study population enrolled in the 5-year prospective survey conducted by the Heart Institute, Tokyo Women's University. We separated the prognosis of AMI into two prognostic groups, one with early death of initial failure type and the other with late death of weak abrasion failure type. It was found that a prognostic factor of early death, mostly caused by cardiogenic shock or cardiac failure, was Killip classification, whereas, in the late death, mostly caused by cardiac rupture or perforation, Q type MI and age other than Killip classification were found to be influential prognostic factors.

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The purpose of this study was to evaluate the degree and amount of movement of the abutment tooth and denture base influenced by the direct retainer of distal extension removable partial denture and the location of functional loading, then to suggest direct retainer design with minimal adverse effect and with optimum functional loading location for residual tissue. The displacement of the abutment tooth and inclination of the denture base were determined, with 30 N as work load utilizing simulation model and strain guage system, about two types of direct retainers with mesial or distal rest and nine loading points on denture base. Displacement and inclination was determined with the one-way analysis of variance and Scheffe's multiple test was performed. The results revealed that type of direct retainer influenced on the magnitude rather than direction of the abutment tooth displacement. The distal displacement of abutment tooth was significantly less in Type M clasp (with mesial rest and connection) than in Type D clasp (with distal rest and connection) (p<0.05). The location of loading points influenced both of the magnitude and direction of the abutment tooth and denture base movement. Posterior and lingual loading resulted in significantly distal displacement of abutment tooth (p<0.05).

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An analysis of static occlusion including occlusal force and occlusal contact area in intercuspal position may be helpful but a dynamic analysis of occlusion should be regarded as more important for analyzing the stomatognathic system. Anthropological research has shown that the Japanese and the Mongolian populations share morphological and genetic similarities, although their dietary lives are not the same. The purpose of this study was to evaluate the relationship between environmental factors such as dietary life and stomatognathic function with a dynamic analysis of physiological tooth displacement. Ten clinically healthy subjects were recruited (mean age 24.8 ±1.0 years). The subjects were divided into two groups 1) Mongolian group: five Mongolians grown with a more or less natural texture diet and 2) Japanese group: five Japanese grown with a relatively soft diet. The displacement of the upper left first molar was measured during function using a three-dimensional tooth displacement transducer Type M-3. The tooth displacement in the Japanese group occurred mostly in an apicopalatal direction, but intruded basically parallel to the tooth axis in the Mongolian group. The stress-strain curve revealed that elastic socket deformation and viscous elements were more pronounced in the Japanese group. It was concluded that environmental factors such as dietary life could influence tooth displacement during function.

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To investigate the mechanism of the glucocorticoids- induced augmentation of skin response, we have recently reported the modulatory effect of glucocorticoids on the regulation of cytokines production in keratinocytes stimulated with various chemicals in vitro through both NF-κB and AP-1 activation. Further to clarify the mechanism in the glucocorticoids-induced augmentation of cytokines production from keratinocytes, we examined the effect of glucocorticoids to keratinocytes without chemical stimulation. Glucocorticoids 10^–4 M inhibited the production of IL-1α from Pam 212 cells. However, lower concentration (10^–8–10^–10 M) of glucocorticoids significantly enhanced the production of IL-1α by Pam 212 cells at both the protein and mRNA levels. In contrast, glucocorticoids had no effect on the production of either TNF-α, IL-6, nor GM-CSF by Pam 212 cells cultured for 6 h. Electrophoretic mobility shift assays (EMSA) revealed that 10^–10–10^–12 M glucocorticoids induced the NF-κB activation in Pam 212 cells, however, augmented AP-1 activation by 10^–8–10^–10 M of glucocorticoids was observed in Pam 212 cells. Furthermore, pyrrolidine dithiocarbamate (PDTC) partially inhibited the IL-1α production and completely inhibited NF-κB expression by Pam 212 cells. On the other hand, MAP-kinase inhibitors (PD98059, SB202190) completely abrogated not only AP-1 activation but the low concentration glucocorticoids-induced IL-1α production. These data indicated that lower concentration of glucocorticoids induced the augmentation of IL-1α production from keratinocytes mediated through the AP-1 pathway and partially through NF-κB pathway.

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It has been recognized that mandibular movements evoke head movements during jaw tapping. However there have been only a few studies that investigated the aspects of head movements during mastication. The objective of this study was to demonstrate the hypothesis that the head moves actively in mastication in order to achieve effective destruction of a food bolus. Head and mandibular movements during gum, gummi candies and kelp chewing among nine adult volunteers have been recorded as time series data with a three-dimensional motion capture system and the vertical components of the movements have been analyzed. To focus on occlusal phase of mastication, the following parameters have been examined: time lag of the head movements at the beginning of occlusal phase, perpendicular velocity of the head at the beginning of the phase of occlusion, and average velocity of the head during occlusal phase. The results showed that the head moved downward in mastication and the velocity of the head movements increased in the order of gum, gummi candies and kelp chewing. There is a possibility that the elasticity of a food bolus affects the activity of head movements, and the kinetic energy was increased to achieve effective destruction of a food bolus.

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The kinetic properties of tetrodotoxin-sensitive (TTX-S) and tetrodotoxin-resistant (TTX-R) Na^+ channels in acutely dissociated neonatal rat trigeminal ganglion neurons were studied using whole-cell and cell-attached patch-clamp recordings. The time course of TTX-R currents was slower than that of TTX-S currents. Compared with TTX-S currents, TTX-R currents had more positive half-activation and half-inactivation voltages. TTX-R currents recovered from inactivation much faster than TTX-S currents. Cell-attached patch recordings showed that the slope conductance of single TTX-S and TTX-R channels was 14.6 pS and 7.8 pS, respectively. TTX-R channels had longer open-times and more dispersed latent-times than TTX-S channels. The convolution of the first latency distribution with the open-time distribution revealed that the slower time course of TTX-R currents is due to longer open-times and more dispersed latent-times of the TTX-R channels compared with those of the TTX-S channels. These findings suggest that TTX-R Na⁺ channels in trigeminal ganglion neurons have similar kinetic property to brain TTX-S Na⁺ channels, but not to structurally homologous cardiac Na⁺ channels.

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Dental pulp self-mineralizes or induces calcified tissue formation, when it is subcutaneously transplanted. This study aims to clarify the nature and process of this tissue calcification by using histochemical techniques and in situ hybridization methods. The dental pulps of incisors from Sprague-Dawley strain rats were homogeneously transplanted into the subcutaneous tissue of the head of another rat. On the 1st day of transplantation, the mRNAs of type I collagen (COL I) and bone sialoprotein (BSP) were expressed in the transplant. On the 5th to 7th days after transplantation, von Kossa-positive, calcified tissues appeared in the transplanted tissues. The mRNAs of COL I, BSP and osteopontin (OPN) were expressed with the same distributions as those of the von Kossa-positive areas, but those of type II collagen (COL II) and bone morphogenic protein 2 (BMP-2) were not expressed in the transplant. When the cellular incorporation of BrdU was examined after its subcutaneous injection into the animals, positive cells were present in the von Kossa-positive calcified foci as well as in their surrounding areas. These results indicate that the transplanted dental pulp possesses the ability to induce cell proliferation resulting in the synthesis of several bone matrix proteins and the formation of calcified tissue. This may give us an insight into the nature and processes of pulp obliteration, which occurs in a human tooth following an episode of trauma.

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