The present paper provides a general review of the biophysiology of natriuretic peptides (NPs) in mammals. NPs, classified as hypotensive hormones, include atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP) and C-type natriuretic peptide (CNP), as well as their receptors, which involve natriuretic and diuretic activity and also blood circulation and volume homeostasis. This review also summarizes the historical background of NP families and cyclic guanosine monophosphate (cGMP)-dependent protein kinase (cGK1) and their biological properties in cardiovascular tissues, heart diseases, renal functions and disease, respiratory and lung failure, gastrointestinal tissue, urogenital and reproductive organs, endocrine activities, the central nerve system, and bone tissue. ANP triggers natriuretic and diuretic activities in the kidney and alters the electrolyte balance via intestinal absorption of water and sodium ions. CNP is involved in promoting wound healing in arterial endothelial cells. The CNPR-related bone pathway plays a causal active role in bone anomalies, and is a regulator of longitudinal skeletal growth diseases such as achondroplasia. CNP-natriuretic receptor B (CNP/NPR-B) system has signifi cant role in the processes of enchondral ossification. Recently, osteocrin/musclin was discovered as belonging to the NP family; it binds with high affinity to NPR-C and plays a role in bone growth.

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The purpose of this study was to investigate the behavior of auto-transplanted cultured periosteum (CP) cells from rats. CP cells were obtained from the calvarium, and bone marrow cells were obtained from the femur. Cell proliferation rates and expression of bone-related protein mRNAs were evaluated. CP and cultured bone marrow (CBM) cells were auto-transplanted into the rectus abdominal muscle and also into the bone cavity of femurs. Immunohistochemical staining with PEBP2αA was performed. Moreover, the expression of mRNAs was also analyzed. Cultured gingival fibrous (CGF) cells were used as controls. The proliferation ratio of CP was significantly higher at 3, 5 and 7 days compared with CBM. Ectopic bone formation in the muscle was observed at 7 days after the CP transplantation. However, little bone formation was observed at 14 days in CBM transplanted areas. PEBP2αA-positive cells in the bone cavity were observed in the CP transplanted group at day 3 and newly-formed bone was seen at 7 day. Th e expression of bone-related protein mRNAs of CP were detected earlier than in any of the other groups. CP has high proliferation potency and can differentiate more quickly than CBM. Thus, CP is the most suitable osteogenic tissue to serve as graft material.

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A rare case of central odontogenic fibroma of the maxilla is presented. A 29-yearold man was admitted because of movable right lateral incisor and dull pain. Panoramic radiograph showed a well-demarcated unilocular radiolucent lesion in the right anterior region of the maxilla. The enucleated tumor was a well-defined firm mass with a solid yellowish-white appearance. Histologically, the tumor was composed of minimally cellular collagenous connective tissue with myxoid matrix. Small epithelial islands were scanty, scattered and inactive appearing in the connective tissue. Immunohistochemically, the fibroblastic cells were positive for vimentin, and the epithelial islands were positive for cytokeratin 14 (CK14) and CK19, which are markers of odontogenic epithelium. From these findings, the tumor was diagnosed as an epithelium-poor type of central odontogenic fibroma. No recurrence has been noted 14 months after surgery.

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A 28-year-old female patient, with a fissured temporal branch of the facial nerve that was located beside the eyeball, underwent suturing of the nerve 25 days after injury. We evaluated the clinical and neurophysiological findings in that case 2 years postoperatively. The ability to raise the eyebrow on the injured side was nearly as good as that on the non-injured side. Contraction of the frontal muscle on the injured side was not complete. We examined electromyographic activities in the frontal muscles, comparing findings between the injured and non-injured side. There was no significant neurophysiological difference between the injured and non-injured side. We suggest that if it is possible to find the fissured nerve that is located at a central site compared to the entrance of the frontal muscle, it would be preferable to suture the nerve even nearly one month after injury in order to improve the cosmetic outcome.

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A case of maxillary osteoblastoma in a 29-year-old man is presented. The patient developed a painful swelling on the right hard palate. Panoramic radiographs revealed a mixed radiolucent/radio-opaque mass surrounded by a narrow radiolucent zone in the apical area of the right maxillary first molar. Under the clinical diagnosis of apical periodontitis, root canal treatment for the molar was carried out. Bleeding from the root canal was observed during the treatment, and the painful swelling disappeared immediately. Shortly afterward, when the bleeding from the root canal stopped, the painful swelling recurred. CT showed a subcortical nodule in the right maxilla. Histopathological examination revealed the lesion was composed of immature bone with broad osteoid matrix at the periphery. The osteoid matrix of the immature bone was fringed with numerous plump osteoblasts without nuclear atypia. Some small foci composed of the neoplastic osteoblasts were associated with the osteoid. Histopathological diagnosis of the biopsy was benign osteoblastoma, and excision of the tumor completely relieved the pain. There has been no recurrence for 7 years. Reduction in vessel pressure due to root canal therapy was considered to have temporarily relieved the pain of osteoblastoma.

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