The mechanism of the bone formation and remodelling has been investigated by many researchers, however, little is known about the role of the local factors in the regulation of the skeletal growth. In this paper, the author attempted to purify and characterize the factors derived from the bovine bone matrix affecting the proliferation and differentiation of the bone cells. The non-collagenous protein fractions extracted from the bovine bone with 0. 5M EDT A/1M NaCl contained factors to promote the proliferation of the embryonic chick calvarium cells in culture. Most of this activity was recovered in an acid-insoluble, calcium-induced precipitate fraction. This fraction was purified by DE-52 ion exchange chromatography and the activities were eluted in several peaks. Two of the active peaks were further chromatographed by gel filtration with S-200 and were eluted between 12, 500 and 25, 000 in an apparent molecular size. Both of these partially purified fractions stimulated the proliferation of the embryonic chick periosteal and skin cells, but inhibited that of the osteoblast cell line (MC3T3-E1) . The effect of the alkaline phosphatase activity by those factors was found in the MC3T3-E1 cells as well as in the embryonic chick calvarium cells. These results suggest a possibility that the multiple factors influencing the proliferation of the osteoblasts may exist in the physiological bone matrix.
The central projection of the trigeminal mesencephalic tract neurons innervating the jawclosing muscle spindles was investigated on the mouse by injecting horseradish peroxidase (HRP) into the masseteric nerve. The HRP-labeled cells were ipsilaterally identified throughout the rostrocaudal extent of the trigeminal mesencephalic tract nucleus. The central processes of the mesencephalic tract neurons terminated ipsilaterally into the nuclei as follows: the trigeminal motor nucleus, trigeminal main sensory nucleus, supratrigeminal nucleus, trigeminal spinal tract nucleus, lateral parts of pontine and medullary reticular formations, vagal dorsal motor nucleus, hypoglossal nucleus and lamina V of the C1-C2 segments of the spinal cord. But, they were not identified in the facial nucleus, solitary nucleus and cerebellum. The localization of the trigeminal mesencephalic tract neurons innervating the jaw-closing muscle spindles was investigated by injecting fluorescent compounds as retrograde tracers into the jaw-closing muscles: masseter, temporal and medial pterygoid muscles. Fluorescent-labeled cells were found intermingled throughout the whole nucleus rostrocaudally. Double or triple fluorescent-labeled cells were not identified in the nucleus. It is suggested that there is no axonal branching from the muscle spindle afferent outside the jaw-closing muscle bellies.
The central projection of lingual proprioceptive afferents was investigated by the horseradish peroxidase (HRP) -labeling technique. Five Japanese monkeys were used in this study. The neuron somata were labeled in the upper three cervical spinal ganglia, C2, C3 and C4, being particularly striking in the C2 and C3 and scantily in the C1 . The central projection of the HRP-labeled cells was found to take three different courses from these ganglia. Firstly, the labeled fibers enter into the dorsolateral fasciculus, through which they ascend the trigeminal spinal tract, branching off to the lamina I in the dorsal horn (C1-C3), and then ascend through the ventral and dorsal portion of the tract, finally terminating in the reticular formation area lateral to the hypoglossal nucleus at the level of the lemniscal decussation. Secondly, the labeled fibers enter into the dorsal horn through the dorsal root, terminating in the lamina V and the spinal reticular formation of the C1-C3 spinal cord segments. Thirdly, the labeled fibers enter into the cuneate fasciculus of the dorsal funiculus, through which they ascend and terminate in the cuneate nucleus of the medulla.
The distribution and structure of the new bone emerging in the early stage after the bone graft was investigated. Fresh autogenous bones were placed in the dog mandible and light microscopic observations on the serial sections of the specimens 2 weeks after the grafting were carried out. The new bones have been collectively called immature bones, nonlamellar bones or woven ones. The author classified these into type I, type II, and type III by the structural charactber. The type I is the less differantiated bone tissue among the 3 types, which has no lamellar structure. The type II is composed of the center part and peripheral part. The center part is a core which consists of type I bone. In the peripheral part, there are fine matrix fibers oriented in parallel with the surface of type II, but there isn't any apparent lamellar structure. The type III has a high stainability to eosin and it's lamellar structure is clear. Ordinarily, according to the distance from the inflammatory focus, there exist in order the type I, the type II and the type III, after bone grafting and the bone formation happens in the same order. It was found that when the inflammation remains or the dense fibrous tissue is formed after the grafting, this process is delayed.
trabeculae by digital image processing. The 32 cases of normal subjects and the 13 cases of patients with mandibular diseases of ameloblastoma, primordial cysts, squamous cell carcinoma and odontoma were analyzed by their intra-oral radiographs in the right premolar regions. The radiograms were digitized by the use of a drum scanner densitometry method. The input radiographic images were processed by a histogram equalization method. The result are as follows : First, the histogram equalization method enhances the image contrast of the textures. Second, the output images of the textures for normal mandible-trabeculae radiograms are of network pattern in nature. Third, the output images for the patients are characterized by the non-network pattern and replaced by the patterns of the fabric texture, intertwined plants karakusa-pattern, scattered small masses and amorphous texture. Thus, these results ind i cates that the present digital image system is expected to be useful for revealing the texture patterns of the radiographs and in the future for the texture analysis of the clinical radiographs to obtain quantitative diagnostic findings.
The purpose of this study is to investigate the morphological changes found in the human caries dentin by optical and electron microscopy. The dental caries invasion showed more variety in the dentin portions. This appeared to be caused by the differences in the structual characteristics of the dentinal tubules and the intertubular dentin. Furthermore, the lateral branches of the dentinal tubules are also deeply concerned in this process. The more the region was near the caries cavity, the more the dentinal structure exhibited remarkable changes. The structual changes in the caries dentin in two directions ocurred earlier and more marked than in one direction. So, it seems that the dentin caries involvement does not always coincide with the degree of the structural changes in the caries dentin.
The purpose of this study was to investigate the effect of accumulated plaque around the apatite implant on both the soft tissue and bone soon after implantation. The lower P3 and P4 and the mesial root of Ml of 18 mongrel dogs were extracted, and 3 months after the 2 types of apaite implants (one-piece type and two-piece type) were placed. One group (A) was kept clean after implantation. To the other group (B) prosthesis was set to accumulate the plaque soon after implantation. The remaining group (C) was kept clean in the early stage and then contaminated. The group A heals well. In group B funnel-shaped bone deffects and severe gin givitis were observed. In group C althogh heavy inflammation was seen in the gingiva, there was seldom observed an obvious bone resorption around the implants. It is clear that the plaque accumulation in the early stage after implantation causes not only gingivitis around the implants but also funnel-shaped bone resorption.