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Biomedical subjects

G Ishikawa

Publications and source records attributed to G Ishikawa.

At least 19 recordsLinked to original sources
PubMed1991

The particle size of hepatitis C virus estimated by filtration through microporous regenerated cellulose fibre.

To estimate the particle size of hepatitis C virus (HCV), a major causative agent of post-transfusion non-A, non-B hepatitis, we filtered plasma or serum samples through microporous cellulose fibres with different pore sizes. The amount of HCV particles in samples before and after filtration was determined by a quantitative reverse transcriptase polymerase chain reaction (PCR) method. Since there is no quantitative biological assay for HCV, except for that in chimpanzees, the HCV titre obtained from the PCR method was used in an equation constructed previously for application to filtration experiments with a flavivirus which is distantly related to HCV. The particle was estimated to be between 30 and 38 nm in diameter, although the possibility remained that larger HCV particles or HCV aggregates with a diameter of more than 39 nm might exist. Double-step filtration through microporous cellulose fibres with a pore size of 35 nm reduced the HCV content to below levels detectable by our PCR method, indicating that it is possible to eliminate HCV particles by simple filtration techniques.

Base Sequence↗
PubMed1985

Nodular hyperplasia of oncocytes in mouse submandibular glands.

Multinodular hyperplastic foci of oncocytes found in mouse submandibular glands were examined ultrastructurally, and their morphogenesis discussed. The oncocytic foci showed lobular architecture surrounded by myoepithelial cells, and tubular formations were frequently present. The cytoplasm of the oncocytes was distended by tightly-packed and non-oriented mitochondria which varied in size and shape. Furthermore, varying numbers of electron-dense fine granules, which were remnants of secretory granules of granular duct cells, were scattered in the cytoplasm. Within the salivary gland parenchyma neighboring the hyperplastic foci of oncocytes, intermediate-type cells between oncocytes and normal salivary gland epithelia were found. The result of the present study shows that the oncocytic change has a tendency to be more frequent in the granular ducts and less in the striated ducts, and that some oncocyte-transformed cells proliferate to form nodular hyperplastic foci.

Animals↗
PubMed1983

Experimental autoallergic sialadenitis in mice. Histopathological and ultrastructural studies.

Experimental autoallergic sialadenitis was induced in SL/Ni mice by one or two injections of syngeneic submandibular gland homogenate emulsified with adjuvant. Light microscopically, there were marked lymphoid cell infiltration in the submandibular glands with high incidence and proliferation of duct epithelia. Furthermore complete alteration of whole glandular lobules in some cases was observed. Ultrastructurally, small and medium sized lymphocytes and plasma cells constituted a major portion of the infiltrating cells, and lymphocytes were frequently observed inside the basal lamina of ductal and acinar regions, especially observed in the small ductal region. In the aggregates of infiltrating cells, the cell remnants of salivary gland epithelia were scattered. Furthermore some of the epithelial cell remnants in aggregates of infiltrating cells could be recognized as epithelial masses which were composed of proliferated duct epithelial cells, though no typical structure of epimyoepithelial islands seen in Sjögren's syndrome was found. Antisalivary duct antibody was detected in only one case.

Animals↗
PubMed1983

Ameloblastoma. Light and electron microscopic study.

Light and electron microscopic studies of ameloblastoma were reviewed. The 21 cases of ameloblastoma examined were classified into 12 cases of the plexiform type and nine of the follicular type. The average age of the patients with the plexiform type was 25.3 years, while that of those with the follicular type was 54.4 years. Histologically, in the follicular type, the tumor cells consisted of two cell types, central polyhedral and star-shaped cells resembling the stellate reticulum and peripheral cuboidal and columnar cells similar to the inner enamel epithelium. The resemblance between the tumor follicle and enamel organ was confirmed electron microscopically. In the plexiform type, however the tumor cells did not show two cell types, but resembled squamous epithelium. Electron microscopically, all cells of the tumor strands had relatively numerous bundles of tonofilaments and were joined together by desmosomes. Differentiation of tumor cells to squamous epithelium less evident than in normal surface epithelium. We speculate that these histological differences between plexiform and follicular types represent the differentiation tendency of the remnant of the dental lamina at the time of neoplastic transformation. What decides the histological pattern is unknown but age may be a factor. Central epidermization with keratinization or microcytic changes was frequently seen in the follicular type. Keratinization and microcystic changes rarely occurred in the plexiform type. We do not believe that these changes are a form of involution or result from multipotentiality of the tumor cells.

Adolescent↗
PubMed1983

Crystalloids in salivary duct cysts of the human parotid gland. Scanning electron microscopical study with electron probe X-ray microanalysis.

Crystalloids found in salivary duct cysts of the human parotid gland were examined by scanning electron microscopical observations with electron probe X-ray microanalysis. The cystic spaces were filled with numerous crystalloids which had a variety of forms with slight eosinophilic and glassy appearance. Scanning electron microscopically, crystalloids were hexagonal and rhombohedral in shape, and cutting the surface showed a polycyclic structure or regular parallel lamination. By electron probe X-ray microanalysis, sulphur was the only detected element. The present study suggests that crystalloids resulted from deposition from supersaturated saliva containing sulphur containing compounds into the cystic lumen or into epithelial cytoplasm.

Crystalloid Solutions↗
PubMed1982

Sarcomas of the mouth and jaws--a study of 16 autopsy cases.

Sixteen autopsy cases of the primary sarcomas of the mouth and jaws were reviewed, which included 1 chondrosarcoma, 3 osteosarcomas, 1 leiomyosarcoma, 7 rhabdomyosarcomas and 4 histiocytic lymphoma (reticulum cell sarcoma). Although the case materials studied were too small, the pattern of the spread of the sarcomas of the mouth and jaw was likely to be divided into two groups, localized and generalized. The former is comprised of chondrosarcoma osteosarcoma, leiomyosarcoma and pleomorphic rhabdomyosarcoma. The latter is comprised of alveolar rhabdomyosarcoma and histiocytic lymphoma. Embryonal rhabdomyosarcoma belongs to either depending on the case. The former, being resistant to local therapy, tended to recur with a contiguous spread but was slow to metastasize. Metastases were limited to the lung and pleura through the hematogenous route. The primary sarcoma of the latter group were not so extended in local spread and occasionally cured with therapy. However, metastases, both hematogenous and lymphogenous, were generalized.

Adolescent↗
PubMed1982

Spindle-cell carcinoma of the oral cavity.

Two autopsy cases are presented of spindle-cell carcinoma of the oral cavity, which were transformations from the pre-existing well differentiated squamous cell carcinoma in Case 1 and verrucous carcinoma in Case 2, after large doses of irradiation. In Case 2, the conventional squamous cell carcinoma existed at the time of biopsy. Our case study suggests that the spindle-cell carcinoma may develop from the verrucous carcinoma by dedifferentiation through the intermediate stage of conventional squamous cell carcinoma.

Carcinoma↗
PubMed1982

Fibromatosis of the oral cavity.

Nine cases of fibromatosis occurring in or near the oral cavity are presented here. They are classified as nodular fasciitis (3 cases), aggressive infantile fibromatosis (2 cases), fibrosing myositis (1 case) and fibromatosis (1 case). Of the 5 cases of nodular fasciitis, 3 occurred from the fascia of the masticatory muscle and 2 from the submucous fascia of the palate and tongue. The aggressive infantile fibromatosis showed a prominent infiltrating growth and an alarming histologic appearance. One of the 2 cases showed a recurrence, but the postoperative course of both cases was uneventful for 13 years and 10 years, respectively. The fibrosing myositis is an unusual fibromatosis of the muscle, which arose within the tongue muscle. The lesion was benign and can be cured by conservative surgery.

Adult↗
PubMed1982

Benign papillary squamous tumors of the mouth.

Sixty-eight cases of benign papillary squamous tumors of the mouth were reviewed to elucidate further their histopathologic variations, as well as to clarify the premalignant nature of these tumors. The cases were classified into five varieties: idiopathic pseudoepitheliomatous hyperplasia (2 cases), papilloma (55 cases), oral florid papilloma (7 cases), inverted papilloma (3 cases) and recurring oral papillomatosis (1 case). The series included very rare cases, to our knowledge, undescribed in the literature. Though a microscopic differentiation between the benign papillary squamous tumors, verrucous carcinoma and well differentiated squamous cell carcinoma is quite difficult, clinical and pathologic recognition of these tumors is imperative, because of the differences in their clinical course and therapeutic requirement. A definite diagnosis should be made after the clinical and microscopic findings have been carefully correlated. Malignant change occurred in the oral florid papilloma and recurring oral papillomatosis.

Adult↗