The Bulletin of Tokyo Medical and Dental University最新文献

In this study, ultrastructural and immunohistochemical studies were performed on the adult rat (15 weeks old) mandibular condyle, with particular attention to the matrix fibers in the condylar cartilage. The fibrous zone had thick collagen fibrils which formed fibril bundles. These collagen fibrils consisted mainly of Type I collagen. From the proliferative zone to the mature zone, the density of the collagen fibrils became higher. In the hypertrophic zone, thick collagen fibrils were formed around the chondrocytes. Immunohistochemical study indicated that these collagen fibrils consisted mainly of Type I collagen. Therefore, it was confirmed that the hypertrophic chondrocytes in this tissue had one of the osteoblastic phenotypes.

To clarify the mechanism of the high incidence of ischemic heart disease in the diabetics, we studied the particle size of the lipoprotein with particular attention to the structural abnormality. Using high performance liquid chromatography, the particle size of the lipoprotein was determined with elution volume, which was precisely correlated with the particle size. The particle size of low density lipoprotein (LDL) from the diabetics with normolipidemia is larger than that from the nondiabetics (p less than 0.001) in the elution pattern of triglyceride. The examination of the elution pattern of the triglyceride and cholesterol revealed that this large LDL was composed of a large amount of triglyceride. These characteristics of the large LDL resembled that of the atherogenic intermediate density lipoprotein. The particle size of high density lipoprotein (HDL) from the diabetics with normolipidemia was larger than that from the nondiabetic controls (p less than 0.001), detected by the elution pattern of triglyceride. The comparison of the triglyceride and cholesterol elution pattern indicated that also the large HDL in the diabetics with normolipidemia was rich with triglyceride, which was reported to inhibit the activity of the lipid transfer protein. These facts revealed that the disorder of the lipid metabolism not accompanied with hyperlipidemia produced the large LDL and HDL, which might lead to the excess mortality rate of the ischemic heart disease in the diabetics even with normolipidemia.

There have been many arguments on the irritating mechanisms of the composite resin on the dental pulp. While the direct irritative effect of the resin has been preferred, some authors considered that the marginal microleakage and the resulting bacterial infection play a more important role in inducing the complicating pulp irritation. We developed a new filling technique, called the direct inlay restoration method, which could prevent the marginal leakage associated with the polymerization shrinkage of the adhesive composite resin. In this study, we tried to apply our method clinically. None of the 440 cases which were filled with the adhesive composite resin and 60 cases out of 64 cases in which the pulps were directly capped with the adhesive composite resin developed any signs and symptoms of pulp irritation. The other 4 cases developed signs of pulp irritation. Two of those 4 cases were pulpectomized due to spontaneous pain and the other 2 cases turned out to be well after re-restoration. With the informed consent of the patients, the direct pulp capping using the adhesive composite resin was experimentally performed on 6 caries-free 3rd molars and the histopathological examination of these capped molars revealed that neither significant degenerative nor inflammatory changes were brought about in the dental pulp. These clinical and histopathological observation suggest that the dental pulp irritation after resin filling is not induced by the composite resin itself.

The net cholesterol transfer activity from high density lipoprotein (HDL) to low density lipoprotein (LDL) was determined in the patients with coronary heart disease (CHD) to examine its effect on the pathogenesis of arteriosclerosis. Furthermore, in the CHD patients with high HDL cholesterolemia (more than 60 mg/dl), the HDL particle size was measured by high performance liquid chromatography. A significant cholesteryl ester transfer activity (P less than 0.02) was noted in the CHD patients with low HDL cholesterolemia (less than 60 mg/dl). The rate of cholesteryl ester transfer activity (cholesteryl ester transfer activity/hour) inversely correlated with the serum HDL cholesterol value (r = -0.483, P = 0.096) in the patients with CHD. These results suggest that an increase of CETA caused a low HDL cholesterol value in the CHD patients with low HDL cholesterolemia and it may have the risk of causing CHD. However, an increase of the CETA was not found in the CHD patients with high HDL cholesterolemia compared to the normal subjects, the HDL particle size being significantly greater than that in the normal subjects. In the CHD patients with high HDL cholesterolemia, the large size of HDL may have the risk of causing CHD.

Transferrin receptor expression in oral tumors was examined by staining with monoclonal antibody against the human transferrin receptor. The cells with positive reaction were recognized in the basal and parabasal layers of the normal epithelium. The staining was found in all the malignant tumors but not in the benign tumors. These results suggest that the immunohistochemical analysis of the transferrin receptor is useful for the diagnosis of oral malignant tumor in addition to the clinical and pathological examinations.

Calcium ionophore A23187-induced liver damage was studied in perfused rat liver and isolated hepatocytes. Two groups of calcium antagonists, dihydropyridine-type and nondihydropyridine-type, were examined for their protective effects on A23187-induced liver damage. The former calcium antagonist inhibited cell damage at pharmacological doses, whereas nondihydropyridine-type calcium antagonists were unable to prevent A23187-induced cytotoxicity. Different inhibitors, such as cAMP phosphodiesterase inhibitor OPC3689, calmodulin inhibitor W-7, and C-kinase inhibitor H-7, were tested in isolated hepatocytes to determine whether intracellular signal transduction systems are involved in the liver cell injury produced by A23187. Calcium ionophore A23187-induced LDH activity of the medium was depressed by W-7 and H-7 to 55 +/- 4% and 63 +/- 4% of controls (p less than 0.01), respectively. However, OPC3689 did not show a protective effect. We conclude that A23187-induced liver cell injury was inhibited by dihydropyridine-type calcium antagonists which may interfere with activation of calmodulin and C-kinase.

The author tried to determine the secretory immunoglobulin A (SIgA) level in the whole saliva of healthy subjects and patients with oral diseases by the enzyme-linked immunosorbent assay (ELISA) technique. An ELISA system that was previously developed for determining the SIgA level in the pancreatic juice was modified and was proved to be applicable for the SIgA in the whole saliva. It was found that the SIgA in the whole saliva could be determined with excellent reproducibility and linearity when the samples were diluted 1,000-fold. This assay method was superior to the conventional techniques in terms of accuracy, covering a wide range SIgA levels in the saliva. In the 74 healthy subjects, the SIgA level in the whole saliva did not show any major age- or sex-related difference. However, patients with leukoplakia, lichen planus and carcinoma in the oral cavity showed higher levels of SIgA. The elevated levels of SIgA in the saliva of these patients suggested that some local changes in immunological competence might occur due to prolonged exposure to the antigen in the oral cavity.

A new comparative method has been developed for evaluating morphological differences between a pair of teeth. This method consists of five steps: 1) digitization of the surface morphology of the teeth, 2) standardization to enable comparison of the teeth on a common axis, 3) reversal of data on one tooth to enable comparison with the opposite tooth, 4) qualitative evaluation by computer graphic superimposition and 5) quantitative evaluation by the set operation. To illustrate its effectiveness, this method was applied to a pair of extracted premolars. Application to the dental crown on a clinical plaster cast was also discussed.