Biomedical subjects

I Semba

Publications and source records attributed to I Semba.

27 records · Page 2Linked to original sources

PubMed1996

Histomorphometric analysis of osteoclastic resorption in bone directly invaded by gingival squamous cell carcinoma.

Whole frontal sections of the mandibular bone from 18 patients with gingival squamous cell carcinoma showing direct bone invasion were prepared for histometrical analysis by a non-decalcified grinding method. The osteoclast cytoplasmic area in tumor sites was larger and its relative frequency distribution was broader than that of osteoclasts in non-tumor sites. The index of bone resorption was significantly increased, while that of bone formation was decreased, in the tumor sites compared to the non-tumor sites (P < 0.01). In the tumor sites, the indices of bone resorption and formation in the group showing greatest chemotherapy and radiation therapy effects (CRE) were significantly different from those in the group with low CRE (P < 0.01). A history of irradiation therapy was associated with significantly decreased bone resorption (P < 0.05).

Adult↗

PubMed1996

Vertebral growth disturbance in rapidly growing rats during 14 days of spaceflight.

The effect of 14 days of spaceflight on the vertebrae of rapidly growing rats was studied. The hardness of the vertebrae was measured with a Knoop microhardness tester, and bone mineral density was measured from X-ray photographs. Histomorphometric examination was performed with a microcomputer-aided system. No significant difference (P > 0.05) was observed between flight rats and ground controls with regard to mechanical hardness or bone mineral density. However, histological examination revealed irregular thickening of the endosteal surface of cortical bone in the flight rats, whereas it was uniform in the ground controls. The relative area of lamellar bone showed a significant reduction (P < 0.001) in the flight rats. These findings suggest that the structural disturbances were due to retardation of endosteal modeling and remodeling. We conclude that delay of vertebral maturation can occur in rapidly growing rats after even short-term exposure to microgravity.

Animals↗

PubMed1995

Evidence for apoptosis of murine macrophages by Actinobacillus actinomycetemcomitans infection.

The gram-negative bacterium Actinobacillus actinomycetemcomitans is considered an important etiological agent in periodontal diseases. In this study, we show that A. actinomycetemcomitans strains are cytotoxic for the murine macrophage cell line J774.1. On the other hand, Porphyromonas gingivalis strains, other gram-negative oral species implicated in adult periodontitis, showed weak cytotoxic effects. For this to occur, A. actinomycetemcomitans had to gain entry into the macrophages, since cytotoxicity was prevented by cytochalasin D. We demonstrate that cell death induced by A. actinomycetemcomitans Y4 occurs through apoptosis, as shown by changes in nuclear morphology, an increase in the proportion of fragmented DNA, and the typical ladder pattern of DNA fragmentation indicative of apoptosis. We further sought to determine whether the cytotoxicity induced by A. actinomycetemcomitans Y4 could be modulated by the protein kinase inhibitors H7 and HA1004. Apoptotic cell death induced by A. actinomycetemcomitans Y4 was suppressed by H7 but was relatively unaffected by HA1004. These findings suggest that the signals of protein kinases may regulate apoptosis induced by A. actinomycetemcomitans Y4. The ability of A. actinomycetemcomitans to promote the apoptosis of macrophages may be important for the initiation of infection and the development of periodontal diseases.

Actinobacillus Infections↗

PubMed1994

Pigmented ameloblastic fibro-odontoma with melanophages.

A case of pigmented ameloblastic fibro-odontoma in the mandible of a 9-year-old Japanese girl is reported. In this tumor, melanin was widely distributed in the nests of the odontogenic epithelial component, and an aggregation of large round melanophages with a large amount of melanin similar to nevus cells was observed in the areas of the connective tissue component. A considerable number of dendritic cells that were considered to be melanocytes were scattered in the epithelial nests. This is the first case of pigmented odontogenic tumor that showed such extensive pigmentation with an aggregation of melanophages.

Child↗

PubMed1994

Glandular odontogenic cyst: analysis of cytokeratin expression and clinicopathological features.

The glandular odontogenic cyst (GOC) is a rare odontogenic cyst which is still controversial in regard to classification, terminology, and origin. The first Japanese case of GOC is reported. Immunohistochemical examination for expression of cytokeratins and epithelial membrane antigen by monoclonal antibodies suggested that the lining epithelium was of odontogenic origin with metaplastic mucus-laden cells. We have reviewed the literature and compared the clinicopathological findings of the reported case of GOC with those of botryoid odontogenic cysts (BOC). The anatomical location, age range, and sex of GOC cases were very similar to those of BOC. GOC appears to be a multiocular and mucoepidermoid variant of non-keratinizing odontogenic cysts, which also includes BOC. GOC should be separated from the other types of odontogenic cyst and central mucoepidermoid tumours of salivary gland origin.

Aged↗

PubMed1993

Gingival leiomyomatous hamartoma: immunohistochemical and ultrastructural observations.

A rare case of leiomyomatous hamartoma of the gingiva is reported and the immunohistochemical and ultrastructural features described. A polypoid mass which presented with the appearance of a congenital epulis was located in the midline of the maxillary alveolar ridge of a two-year-old boy. Histologically, the mass was without a capsule and was composed mainly of irregularly arranged fasciculi of large spindle cells resembling smooth muscle cells. The immunohistochemical staining for desmin was strongly positive in these cells. Many nerve fibers were intermingled with them. Ultrastructurally, the cytoplasm was filled with thin filaments associated with dense patches. Numerous pinocytotic vesicles were present on the cytoplasmic membrane. These findings indicated that the mass consisted mainly of mature smooth muscle cells. The clinical and histological features suggest that the smooth muscle cells in the lesion are of hamartomatous or choristomatous origin, in contrast to true leiomyoma or granular cell congenital epulis.

Cell Nucleus↗

PubMed1990

Eosinophilic granuloma showing rapid regression. Report of a mandibular case with application of a modified PNA staining method for demonstration of Langerhans-type histiocytes.

A mandibular eosinophilic granuloma in a 16-year-old male is reported. This case showed rapid regression, which was clearly demonstrated by histopathological examinations of both preoperative biopsy and surgical materials. Transformation from an eosinophilic granuloma to a xanthomatous granuloma with multinucleated giant cells was observed after only 26 days. Special staining of paraffin sections with peanut agglutinin (PNA) and use of electron microscopy showed that the main component of the lesion in the biopsy material was Langerhans-type histiocytes. These cells had disappeared from the lesion by the time of the operation. At the same time, the number of infiltrating eosinophils was also markedly reduced. It seems appropriate to consider that the rapid regression of this disease was correlated with the rapid reduction in the number of Langerhans-type histiocytes appearing in the granulomatous foci, as well as the number of infiltrating eosinophils.

Adolescent↗

PubMed1989

A histometrical analysis of age changes in the human lingual artery.

The lingual arteries from 450 Japanese autopsies, ranging in age from 3 months to 106 years, were carefully selected for examination of the ageing process. Histopathologically, a focal intimal thickening, considered to be an intimal cushion rather than an atheromatous lesion, was observed in cases as young as 6-month-old infants. The most frequent intimal change was diffuse fibrous thickening, present throughout the life span. Luminal obstruction caused by extensive atheromatous plaques was never seen. The internal elastic lamina regressed with increasing age. Histometrically, the radius of the artery increased not only during the developmental period but also after maturation, with a modified exponential curve. The thickness of the media also increased with a modified exponential curve until the third decade, when it became fairly constant. The thickness of the intima increased exponentially throughout the life span. The value of the relative luminal radius, considered to be an index value for arterial senescence, remained constant until the seventh decade and then showed a distinct decrease. This luminal narrowing, resulting primarily from intimal thickening, was compensated for by outward growth of the media and remodelling of the internal elastic lamina with increasing age until the seventh decade. The changes in the dimensions of both media and intima, and the histopathological alterations in the lingual arterial wall with progressing age, suggest that disturbances of homeostasis in the media play an important role in age-related progression of arteriosclerotic change.

Adolescent↗

PubMed1984

Malignant endothelial neoplasm arising in the area of lymphangioma: immunohistochemical and ultrastructural observation.

This report presents a rare malignant endothelial neoplasm which arose at the site of a pre-existing lymphangioma. The lymphangioma was located on the right buccal mucosa, and the malignant neoplasm arose 17 years after irradiation of the initial tumor. Clinical, light microscopic and immunohistochemical (Factor VIII-related antigen and Ulex europaeus Agglutinin-I) studies were made, together with observations by transmission and scanning electron microscopy. These studies provide evidence that this malignant neoplasm was well-differentiated and had not yet lost the characteristics of normal lymphatic cells.

Adult↗