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Biomedical subjects

K Tanne

Publications and source records attributed to K Tanne.

156 records · Page 9Linked to original sources
PubMedDate not supplied

Long-term granular diet may lead to declined resistance to trauma of the temporomandibular joint.

This study was carried out to determine the effect of food texture on the response to trauma of the temporomandibular joint in mice. Animals were fed either a solid or granular diet after weaning. At 8 weeks old, condylar hypermobility was induced by forcing the mouth wide open ten times under ether anaesthesia. This procedure was repeated 10 times once daily for 10 consecutive days. The temporomandibular joint tissues were observed microscopically on day 0 and then 2 days, 5 days, 2 weeks, 3 weeks and 5 weeks after the last forced opening. Eighteen male mice were used in total, three for each timepoint. A proliferation in synovial surface cells and an increased number of capillaries were seen at day 2 in the mice fed a granular diet, but not in those fed a solid diet. Multiple cell layers of the synovial membrane, dilated capillaries and fibrin deposits were expanded further between day 2 and week 5 in the mice fed a granular diet, but not until day 5 to week 5 in the mice that had been fed a solid diet. At week 3, the mice fed a granular diet showed erosion of the anterior articular disc. This was observed in both dietary groups at week 5. This study suggests that, in advanced countries, people who habitually eat easily chewable food should be advised that such practice may lead to a decline in the resistance to trauma of the masticatory system.

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PubMedDate not supplied

Transplantation of new autologous biomaterials into jaw cleft.

This study compared bone-marrow grafting using chondroid or fibula bone grafts transplanted into simulated alveolar bone defects in mice. The osteogenic procedure was also investigated. As an experimental model of the maxillary alveolar bone cleft, suitable for testing bone-inductive materials, a surgical trephine with a low-speed dental engine was used to form critical-sized defects in the pre-maxillary bones of male mice. Distraction osteogenesis was performed using an external fixation device. The osteotomy site was surrounded by an external callus, consisting of hyaline cartilage, that contained a large quantity of chondroid bone. Transplanted bone within chondroid bone was characterized by bone formation and remodelling 30 days post-transplantation, and bone adhesion following chondroid bone grafting was better than adhesion following fibula grafting. The present findings are the first to demonstrate the potential of chondroid bone transplantation as a new therapeutic system of bone grafting, suitable for bone substitution in craniofacial bone defects.

Animals↗
PubMedDate not supplied

Amyloid beta protein deposition in osteopetrotic (op/op) mice is reduced by injections of macrophage colony stimulating factor.

The deposition of amyloid beta (Abeta) protein is a neuropathological change that characterizes Alzheimer's disease. Animals with the osteopetrosis (op/op) mutation suffer from a general skeletal sclerosis, a significantly reduced number of macrophages and osteoclasts in various tissues, and have no systemic macrophage colony stimulating factor (M-CSF). This study examined the effect that M-CSF injections had on Abeta deposition and microglial cell distribution in the brains of normal and op/op mice. Abeta-positive plaques were detected in the cerebral cortex of op/op mice, but not in normal mice. M-CSF reduced the numbers of Abeta-positive plaques in op/op mice. The microglial cell population was reduced in op/op mice compared with normal mice, and M-CSF increased the numbers to 65.8% of that observed in normal mice. Our results suggest that a clearer understanding of the role that microglial cells play in Abeta deposition may help determine the mechanisms involved in the pathogenesis of Alzheimer's disease.

Amyloid beta-Peptides↗
PubMedDate not supplied

Morphological change of the nasopremaxillary suture in growing "toothless" osteopetrotic (op/op) mice.

Osteopetrotic (op/op) mice are known to commonly show a failure of tooth eruption. It is also well understood that masticatory function is highly associated with the craniofacial morphology of the growing mouse; however, the effects on sutural growth have not been studied. The present study was conducted to examine, in detail, the morphological and histological changes of the nasopremaxillary suture in these mutant mice and to assess a role of mechanical stress from mastication in the sutural growth. The width of the nasopremaxillary suture was measured on the section for the superior (P1), middle (P2), and inferior (P3) levels. The width of the nasopremaxillary suture for the P1 level in the normal mice fed a solid diet was significantly smaller in 30-day-old mice than in 15-day-old mice, whereas the width for the level P3 was significantly greater in the 30-day-old mice than in the 15-day-old mice. These changes in the sutural space were more prominent in the normal mice fed a solid diet than in the normal mice fed a granular diet. The sutural widths for all the levels became smaller in the 30-day-old op/op mice than in the 10-day-old op/op mice. The endocranial area of the nasopremaxillary suture showed synostosis in 30-day-old op/op mice. In both the normal and op/op mice, the number of tartrate-resistant acid phosphatase (TRAP)-positive cells was greatest at the age of 15 days. Moreover, the TRAP-positive cell number was smaller in the op/op mice than in the normal mice for all the experimental stages. Since, in general, mastication begins in mice after tooth eruption, i.e. from 15 to 30 days after birth, the present findings suggest that failure of tooth eruption and the reduced masticatory function restrict sutural modification.

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PubMedDate not supplied

Remodeling of the sagittal suture in osteopetrotic (op/op) mice associated with cranial flat bone growth.

It is well known that cranial flat bone experiences growth and development at the sutural interface, which is regarded as a neutral zone to control mechanical stimuli. In osteopetrotic (op/op) mice, meanwhile, cranial deformation is produced by the deficiency of osteoclasts and the subsequent defect of bone resorption. It would be a reasonable assumption that such disturbance in bone remodeling affects sutural modification and the relevant cranial flat bone development. The present study was thus conducted to examine histological features of the sagittal sutures in op/op mice, with special reference to the relevant bone remodeling. The sagittal sutures in 10-, 15-, 30-, and 60-day-old normal and op/op mice were observed microscopically. Furthermore, osteoclastic activity was evaluated on the sections stained with tartrate-resistant acid phosphatase (TRAP). The sutures of 15-day-old op/op mice showed stenosis and synostosis, and less-developed collagen fibers associated with an irregular arrangement of fibroblasts, whereas these changes were rarely found in normal mice. Osteoclasts were hardly detected in the parietal bones around the sutures of op/op mice, although the number was numerous in normal mice. These results emphasize that congenital deficiency in osteoclast produces unbalanced bone remodeling at the sutural interface and on the surfaces of the cranial bones, which is assumed to be closely related to cranial bone deformity in op/op mice.

Animals↗
PubMedDate not supplied

Lack of the bone remodeling in osteopetrotic (op/op) mice associated with microdontia.

Osteopetrosis is an inherited metabolic disease characterized by an excessive accumulation of bone. This is associated with an osteoclast deficiency. Osteopetrosis is always accompanied by the failure and/or delay of tooth eruption. The present study was conducted to examine in detail the morphological and histological changes of growth of the third molars in the osteopetrosis (op/op) mouse. At the age of 10 days, normal and op/op mice showed no detectable difference in the shape of the third molar follicles. However, the third molars in the op/op mouse became obscured by the proliferation of neighboring bone trabeculae. Moreover, no tartrate-resistant acid phosphatase-positive cells were detected on the bone surfaces of 10-day-old op/op mice. Ankylosis between the root dentin and proliferating bone trabeculae was a common feature in the 20- and 30-day-old op/op mice. The third molars erupted into the oral cavity before the age of 30 days in normal mice, and the crowns, roots, and periodontal ligaments appeared well developed. Throughout the experiment, it seemed that the primary cause of the microdontia and ankylosis of the developing root in the mutant mouse was a deficiency of osteoclasts, with attendant lack of bone remodeling.

Age Factors↗
PubMedDate not supplied

Facial skeletal growth in growing "toothless" osteopetrotic (op/op) mice: radiographic findings.

The defective bone resorption in the osteopetrotic (op/op) mouse brings about failure of tooth eruption. Furthermore, the op/op mouse has been studied as a "toothless" mouse in recent morphological and physiological investigations of the relationship between mastication and masseter muscle development. The present study was conducted to examine in detail the nasal bone and the premaxillary bone in this mutant mouse and to assess the roles of incisor growth and the mechanical stress of mastication in nasal bone and premaxillary bone growth. The forms of the nasal bone and the premaxillary bone were observed using roentgenography in both toothless op/op and normal (control) mice. In the op/op mouse, the nasal bone and the premaxillary bone show remarkable deformity. In contrast, the normal mouse appears well developed. This suggests that growth of the incisor root is important to normal upper jaw growth in the mouse. Furthermore, it is proposed that the upper facial phenotype seen in the op/op mice results from not only decreased bone resorption, but also from absence of the mechanical stress provided by normal mastication.

Age Factors↗
PubMedDate not supplied

New biomaterials and methods for craniofacial bone defect: chondroid bone grafts in maxillary alveolar clefts.

The purpose of this study was to evaluate autogenous osteogenic marrow within chondroid bone grafts in simulated alveolar defects of mice in order to determine the ability of the graft material to effectively close the cleft from an osseous standpoint and to observe the effect of the grafting procedure. Critical-sized defects were made in the premaxillary bones of male mice using a surgical trephine and a low-speed dental engine as a model of the maxillary alveolar cleft for testing bone-inductive agents. Premaxillary trephine defects were not repaired by fibrous tissue or bone formation 30 days after operation. This nonhealing bony wound of the premaxilla in mice may be useful as a model for studying the effect of bone-inductive agents on the healing of alveolar clefts. Distraction osteogenesis is a recently advanced principle of bone lengthening in which a long bone separated by osteotomy is subjected to slow progressive distraction using an external fixation device. The osteotomy site was surrounded by an external callus consisting of hyaline cartilage. The callus contained a lot of chondroid bone. The transplant bone within chondroid bone was characterized by bone formation and remodeling 30 days after transplantation. Throughout the experiment, our findings demonstrated, for the first time, that the transplant bone that contains chondroid bone may be used clinically in relation to craniofacial bone defects to improve the treatment of bone grafts.

Alveolar Process↗
PubMedDate not supplied

Influences of osteoclast deficiency on craniofacial growth in osteopetrotic (op/op) mice.

It is well known that the defect in bone resorption in osteopetrotic (op/op) mice brings about deformation of the cranium and failure of tooth eruption. However, the influences on longitudinal growth of the craniofacial skeleton have not been elucidated. This study was thus conducted to examine craniofacial morphology and longitudinal changes in the op/op mice by means of morphometric analysis with lateral cephalograms. Lateral cephalograms, taken every 10 days from 10- to 90-day-old mice, were analyzed on a personal computer for 11 measurement items. For the nasal bone region, the most prominent differences were found between the op/op and normal mice. The anterior cranial base and occipital bone height presented almost equivalent growth changes in both the op/op and normal mice. The size of mandible, meanwhile, was significantly smaller in the op/op mice than in the normal controls. The gonial angle was also significantly larger in the op/op mice than in the normal mice throughout the experimental period. Thus, substantial differences in craniofacial growth were demonstrated in various areas of the craniofacial complex, which are assumed essentially due to the lack of osteoclastic bone resorption during growing period. Since the difference became more prominent in the anatomic regions relevant to the masticatory functions, it would be a reasonable assumption that reduced masticatory function is also a key determinant for the less-developed craniofacial skeleton in the op/op mouse.

Animals↗
PubMedDate not supplied

Morphology of the mandibular condyle in "toothless" osteopetrotic (op/op) mice.

The defective bone resorption in the osteopetrotic op/op mouse brings about cranio-facial deformation and failure of tooth eruption. This study was conducted to elucidate the morphological changes of the condylar head and mandibular ramus in growing op/op mice. In normal mice, the condylar head is much broader than the ramus beneath it, enlargement and ossification of the condylar head begin after weaning, and the ramus becomes compact bone tissue. None of these changes were found in the op/op mice in the present observation. The condylar head was small, and its inner side was occupied by hypertrophic cartilage cells. In spite of the lack of bone resorption in op/op mice, the compaction of the mandibular ramus, which was composed of bone trabeculae, occurred later than that in normal mice. In view of recently studies reported evidence that local mechanical stress regulates the bone formation, we consider that undergrowth of the condylar head and the ramus in the op/op mouse results from not only a deficiency of osteoclasts but also insufficient mechanical stress from mastication.

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PubMedDate not supplied

Influences of ovariectomy and orchiectomy on the remodeling of mandibular condyle in mice.

Ovariectomy (OVX) and orchiectomy (ORX) are well known to increase bone turnover; however, the influences on condylar remodeling are not fully understood. The purpose of this study was to examine histological changes of the mandibular condyles in OVX and ORX mice in comparison to the femora. Eighty 8-week-old mice were used in this study. In each of the experimental and control groups, five mice were sacrificed 2, 4, 8, and 12 weeks after surgery for OVX and ORX. Histological changes of the mandibular condyle were studied in comparison to the femur, which is liable to undergo the influences of OVX and ORX. The number of TRAP-positive cells and the thickness of articular cartilage layer were also quantified. TRAP-positive cells in the condylar head of OVX and ORX mice exhibited the most prominent increase 4 weeks after the surgery and approached the control levels at the later experimental stages. Trabecular bone volume in the condyle of the OVX and ORX mice also decreased, although the rate was less than in the femora. It is shown that influences of OVX on the remodeling of femora appear earlier than those of ORX, whereas OVX and ORX affect the remodeling of condyle during the same growth period. It is also demonstrated that the influences of OVX and ORX are less in the condyle than in the femora. These findings emphasize that the influences of OVX and ORX on bone remodeling are varied by sexual difference and the type of bones.

Acid Phosphatase↗