Kanagawa shigaku. The Journal of the Kanagawa Odontological Society最新文献

Using two types of cultured cells, fibroblasts (NRK-49F) and epidermal Cells (NRK-52E) of a normal rat kidney, the number of transferrin (Tf) receptors and the amount of Ga-67 uptake was determined in both proliferative and quiescent phases. The following results were obtained: 1. There was almost no uptake of H-3 thymidine in the quiescent phase in both NRK-49F cells and NRK-52E cells. 2. Ga-67 uptake in the quiescent phase decreased to about 28% of the value in the proliferative phase in NRK-49F cells and to about 23% in NRK-52E cells. 3. The number of Tf receptors in the quiescent phase decreased to about 10% of that in proliferative phase in both NRK-49F and NRK-52E cells. 4. Using the immunoperoxidase method with Nu-TfR1 (anti-Tf receptor monoclonal antibody), the antigen, Tf receptor, was confirmed in the region corresponding to the cell membrane in the proliferative and quiescent phases. In addition, highly positive findings were observed frequently during cytokinesis in the proliferative phase. These results suggest a correlation between the number of Tf receptors and Ga-67 uptake in the proliferative and quiescent phases it indicates that Ga-67 uptake into the cells depends on the number of Tf receptors.

It has been thought that the incorporation of Pb and Cd into human body, especially calcified tissues including the tooth, has altered the physiological processes of development. But, the biochemical events that initiate this process remain quite unknown. The present study attempt to explore the effect of Pb and Cd on human periodontal ligament fibroblast-like cells of the permanent tooth (HPLF) and the deciduous tooth (HPLF-Y) with respect to the cell growth, ALPase activity and incorporation of 14C-amino acids. HPLF and HPLF-Y migrated from a explant and subcultured according to the previously described method of Saito were inoculated 1.25 x 10(4) cells/cm2 in D-MEM supplemented with 2 mg/ml FCSP, 50 micrograms/ml ascorbic acid and antibiotics. After 24 hrs, HPLF and HPLF-Y were treated every two days for 10 days with 0-200 microM Pb or 0-10 microM Cd. Protein contents, DNA contents and ALPase activity were determined by Bio-Rad protein assay, deaminobenzoic acid assay and p-nitrophenylphosphate (pH 10.15) assay respectively. At 6 days HPLF were incubated with 3H-thymidine (TdR 2.0 microCi/well) and then the incorporation of 3H-TdR into cold TCA precipitates was assayed by a liquid scintillation counter. And also, at 6 days HPLF and HPLF-Y were incubated with 14C-amino acids (2.0 microCi/60 mm dish) for 24 hrs. The cell layers labeled with 14C were extracted with 15 mM Tris-HCl buffer containing 7 M urea (pH 7.4) and applied to the gel permeation chromatography of HPLC system to separate the fractions according to molecular weight. The HPLF and HPLF-Y incubated with Pb and Cd were morphologically identical. Pb stimulated the protein contents of extracellular matrix of HPLF, but not HPLF-Y. Cd inhibited the protein contents of cell layers of HPLF and HPLF-Y. With increasing concentrations of Pb and Cd, the incorporation of 3H-TdR into HPLF was inhibited. On the other hand, Cd stimulated the ALPase activity per DNA content since the ALPase activity of HPLF and HPLF-Y was decreased by the addition of Pb. The distribution of 14C-labeled protein according to molecular weight did not alter the chromatographic pattern of HPLF incubated with Pb and Cd. But, that of HPLF-Y incubated with Pb was relatively shifted to low molecular size. Therefore, these responser concluded that HPLF were not completely identical with HPLF-Y. Pb and Cd not only had a toxic effect on cell growth, but also they may regulate the metabolic alteration.

Low-energy electromagnetic fields pulsed at frequencies of 60-90 Hz significantly increase healing of chronic fracture nonunions in man. These fields are effective at tissue current levels as low as several orders of magnitude lower than those required for transmembrane depolarization of normal cells. In this study, the effects of PEMF on culture of rat osteoblast-like cells have been examined. The PEMF promoted the growth of these cells, were also found to increase the basal level of [Ca2+]i, and to decrease the responses towards epidermal growth factor (EGF) and serum, when the degree of response was based on the intracellular Ca2+ transient. These effects of PEMF were mimicked by 12-O-tetradecanoyl phorbol 13-acetate (TPA), a potent activator of protein kinase C. Pretreatment of TPA enhanced the cell growth and suppressed the intracellular Ca2+ transient induced with EGF and then serum to about 170% of the control. Then, present study investigated how the PEMF and TPA modulate EGF receptors of these cells. Both PEMF and TPA decreased the level of EGF binding to these cells down to about 65% and 75%, respectively. Scatchard analysis revealed the decrease of EGF receptor without a significant change in the affinity for EGF by both. In conclusion, it was indicated that PEMF acts at cell membrane and modulates the receptors which is essential for cell growth and DNA synthesis.

The concept of orthodontic tooth movement is based on the hypothesis that teeth move as a result of the biological response of periodontal tissues to the mechanical forces applied. There is a widely held hypothesis that mechanical stress generates an electrical signal which sets in motion the subsequent events, as in bone exposed to mechanical forces electrical currents are produced affect bone growth and remodeling. This implies a transduction mechanism which translates the electrical signal into a biochemical message, recognizable by the cellular machine. This study is aimed at the identification of the message and the investigation of its control. In fact, the effect of Pulsed Electromagnetic Fields (PEMF) on the intracellular second messenger, cytoplasmic Ca2+ in Human Periodontal Ligament Fibroblasts (HPLF) was investigated. The resting intracellular ionized calcium concentration ([Ca+2]i) of HPLF cells was 232.7 +/- 25.0 nM, and with PEMF [Ca2+]i increased from 12 hrs to 499.0 +/- 115.5 nM up to 12 hrs, then reached to a steady level through 24 hrs. The PEMF were also found to decrease the responses towards epidermal growth factor (EGF) and serum, when the degree of response was based on the intracellular Ca2+ transient. These effects of PEMF were mimicked by 12-0-tetradecanoyl phorbol 13-acetate (TPA), a potent activator of protein kinase C. Some reports have suggested that fibroblasts of the periodontal ligament contain high alkaline phosphatase (ALPase) activity as much as osteoblast. Since similar results concerning the [Ca2+]i were obtained in osteoblast (OB)-like cells, this experiment also supports the hypothesis that fibroblasts of periodontal ligament have osteoblastic features.

This study was conducted to clarify both changes of periodontal vascular architecture and concomitant remodelling phenomena associated with hard tissues in the healing process of replanted teeth of first premolar. Utilizing both vascular corrosive resin casts method, scanning electron microscopy, and histological examinations, 45 matured mongrel dogs were used for this study. The results were as follows: 1. 4 days after operation: Newly formed vascular networks with a exceedingly irregular course were observed on lower two thirds of the alveolar wall. They derived from comparatively less damaged periodontal vascular components. No vascular networks were observed surrounding in the crevicular area of the replanted tooth where the periodontal membrane tissue was thoroughly damaged when tooth was extracted. 2. 1 week after operation: Newly formed periodontal vascular networks with a slightly irregular course were observed over the entire alveolar bone surface. 3. 2 weeks after operation: Formation of Sharpey's fibers occurred. The surrounding alveolar bone was remodelled and rearrangement of periodontal vascular architecture was observed. Also, several Howship's lacunae were observed on the root surface where characteristic capillary loops with glomerular-like appearance penetrated into these lacunae. 4. 3 weeks after operation: Root resorption was advanced and capillary loops with glomerular-like appearance were extensively distributed in association with each lacunae. On the other hand, the less space where periodontal membrane vasculature occupied, the more space was occupied by osteoid tissue. 5. 4 weeks after operation: Blood vessels within the periodontal space were reduced in number and the osteoid tissue showed bony fusion adjacent to the extensively resorbing surface of dentin. 6. 12 weeks after operation: Functional arrangement of Sharpey's fibers was completed. Restoration of Howship's lacunae on the root surface and two layered arrangements of vascular network within the periodontal space were observed. Newly formed periodontal vascular architecture showed a fine meshwork pattern, which was somewhat different from that of the control (noreplantation) group. 7. 20 weeks after operation: Increased number of capillary loops was observed with leakage of methacrylate resin through the weakened endothelial linings of capillaries in one case. It is supposed that this leakage through capillaries is correlated with the inflammatory root resorption that occurs clinically in marginal periodontitis. Also in some cases, periodontal capillary network showed secondary occlusal traumatic changes. Above results indicated that periodontal vascular architecture varied depending upon the reactions of periodontium following tooth replantation and the prognosis of replanted tooth was deeply associated with repair of periodontal vascular network.

It has been reported by some investigators that deciduous teeth could be useful materials for the analysis of the trace elements available to the human body burden. In this study, an attempt was made to define that uptake of trace elements (Cd, Zn, Pb and Cu) take place during formation of the deciduous tooth. Samples were prepared from exfoliated human upper deciduous central incisors divided into two or three sections at incremental lines includes neonatal line. Samples were dissolved with nitric acid and dried at 80 degrees C. Each element was separated chromatographically using acetone-HCl gradient solution with a cation exchange resin and then analyzed by flameless atomic absorption spectrophotometry. The results were as follows: 1. Ca, P, Ca/P ratio levels showed no significant differences between prenatally and postnatally formed teeth. 2. In the enamel, (1) Cd level showed a tendency to be higher in the postnatally formed enamel, but not significant. (2) Zn and Pb levels were found to be significantly higher in the postnatally formed than in the prenatally formed enamel. (3) Cu level was reversed significantly. 3. In the dentin, (1) Cd and Cu levels in the postnatally formed dentin I were significantly less than prenatally formed denin, and these were almost equal to the postnatally formed dentin II. (2) Zn level in the postnatally formed dentin I was almost equal to the prenatally formed dentin, but that was significantly less than the postnatally formed dentin II. (3) Pb level in the postnatally formed dentin I was significantly less than the prenatally formed dentin and the postnatally formed dentin II. Therefore, the results suggest that the accumulation of Cd and Cu to the deciduous tooth mainly occur in the prenatal and the accumulation of Zn and Pb to the deciduous tooth occur not only in the prenatal but also continuously in the postnatal, and the deciduous tooth can be a useful materials for environmental contamination recorder.

Alkaline phosphatase (ALP) activity has been demonstrated in periodontal ligament (PDL). On the basis of electron microscopic study, distribution of the enzyme in PDL tissue has also been indicated not only as a cell associated activity but also as an extracellular matrix associated activity. This study is concerned with the purification and characterization of the enzyme obtained from bovine PDL tissue. Purification of ALP extracted from the tissue included solubilization with 10 mM Tris-HCl buffer, pH 7.4, containing 0.2 mM MgCl2 and 0.1% Nonidet P-40 and fractionation by sequential chromatography utilizing DEAE-sephacel, Sepharose CL-6B and concanavalin A Sepharose 4B. Purity was established by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). This was followed by staining for ALP activity first with 2 mM beta-naphthyl acid phosphate and 1 mM Fast Blue BB Salt and then the protein with Coomassie Brilliant Blue. SDS-PAGE of the crude enzyme preparations gave a broad band with apparent molecular weight of 110,000-130,000 dalton. ALP activities were separated into two major peaks using Sepharose CL-6B chromatography. The void volume peak showed a purified form of 110,000 dalton ALP (110K ALP) while the second peak contained 120,000-130,000 dalton ALP (120-130K ALP) and other proteins. Sequentially, 120-130K ALP was purified by chromatography on concanavalin A Sepharose 4B. A polyclonal antibody was raised against purified bovine PDL 110K ALP in a rabbit. Immunodiffusion analysis showed that a polyclonal antibody against 110K ALP recognized 120-130K ALP. Analytical affinity chromatography on concanavalin A Sepharose 4B indicated that 110K ALP and 120-130K ALP had distinct affinity to the column which may depend upon the sugar chain structure. Digestion of 110K ALP with phosphatidylinositol-specific phospholipase C affected electrophoretic mobility but 120-130K ALP had no effect. It is suggested that 110K ALP is attached to a cell membrane anchored by a phosphatidylinositol glycan. In conclusion, bovine PDL contains two types of alkaline phosphatase i.e. 110K ALP and 120-130K ALP. Both ALPs are immunologically related although they have different sugar chain moieties. Furthermore, 110K ALP has a membrane anchoring domain. These results suggest that 110K ALP would be localized on the surface of the cell membrane and 120-130K ALP may associated with the extracellular matrix.

Unlabelled: An HB prophylaxis vaccination that included a primary and secondary vaccination was carried out on persons working at this university hospital. In the primary vaccination, the subjects were inoculated the second time with a vaccine derived from human blood plasma obtained from the Kitazato Therapeutic Research Institute. The third time, they were inoculated with a vaccine from the Chemo-Sero Therapeutic Research Institute derived from a second-generation vaccine organized ferment. The vaccine used for the second inoculation was obtained from the Chemo-Sero Therapeutic Research Institute.

Results: A total of 254 subjects were inoculated with the HB prophylaxis vaccination. 1. Of the 216 subjects inoculated with the primary vaccination, at the time of the second inoculation, 65 subjects (30%) tested positive for antibodies 3-4 months following inoculation. There was an especially high rate among females between 20 and 50 years. Thirty-two subjects (15%) tested positive 15-16 months following inoculation with a high rate among females. 2. Among 132 subjects inoculated the third time with the primary vaccination (those who tested negative in the second inoculation of the above vaccine), 76 subjects (58%) tested positive for antibodies 8-9 months following inoculation with a generally high rate among females. Thirty-five subjects (27%) tested positive 15-16 months after inoculation with a high rate among females between 20 and 30 years and among males between 40 and 60 years. 3. Among the 38 subjects who were inoculated the second time with the secondary vaccination, 8 subjects (21%) tested positive for antibodies 5 months following inoculation, with a high rate among females in their 20's.

Orthodontic tooth movement frequently induces the resorption of the tooth root, although valuable information concerning the relationship between the root resorption and force magnitude, duration and types of tooth movement and the condition of periodontium obtained. However, it is incompletely known that the situation of candidated tooth itself of orthodontic movement in which pulpectomized non-vital condition influence the process of root resorption and subsequent repairing. Thus, the study was conducted to clarify the effect by the pulpectomy accompanied with tooth movement on the process of root resorption and regeneration of periodontium. A hundred and fifty Wistar rats, weight 180-200 g, 6 weeks old, were used as experimental animals. Prior to experimental tooth movement, first molars of 50 rats were received pulpectomy on both sides followed by filling of root canal (first group) and those of another 50 rats on single side (second group). Maxillary first molars of the other 50 rats were saved as a vital dental pulp control (third group). The first and the third groups of animals were then subjected to experimental tooth movement with the interproximal insertion of elastic rubber as described by Waldo (1953) for 3 days, 1, 2, 3 and 4 weeks. After tooth movement was terminated, animals were sacrificed by ether inhalation or by perfusion of glutaraldehyde fixation solution. The upper jaw from each rat was dissected and prepared specimens for non-decalcified section and light microscopic section. Root resorption and regeneration of cementum were evaluated quantitatively using the modular system for semiautomatic quantitative evaluation of images on the light microscopic section. Occurrence of external root resorption with multinucleated odontoclast associated with experimental tooth movement in pulpectomized tooth were lesser and later than those of vital teeth. These findings suggest that the dental pulp plays an important role in the processes of root resorption and remodeling of cementum associated with orthodontic tooth movement.