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Biomedical subjects

T Masegi

Publications and source records attributed to T Masegi.

At least 55 records · Page 3Linked to original sources
PubMed1996

Spontaneous vascular mineralization in the brain of horses.

Cerebral vascular mineralization was found in 12 (60%) of 20 3- to 10-year-old healthy horses collected at an abattoir. It was variable in degree and occurred mostly in the pallidal arteries showing two types of lesions; small globoid bodies along capillaries, and amorphous deposits in the wall of arterioles, small- or medium-sized arteries and veins. Both types were strongly positive for periodic acid-Schiff reaction, and weakly positive for von Kossa's and Berlin blue stains. Elemental analysis of the deposit revealed the presence of large amounts of aluminum, moderate amounts of phosphorus, zinc, calcium and iron, and a small amount of sodium.

Aging↗
PubMed1995

Eosinophilic neuronal inclusions in the thalamus of ageing B6C3F1 mice.

The age-related incidence of thalamic neuronal inclusions in the brains of aged B6C3F1 mice and their histopathological and ultrastructural features were studied. Round to oval or rod-shaped eosinophilic inclusions, which were frequently observed in the neurons of the thalamic area, were stained positively with phosphotungstic acid haematoxylin. The inclusions were detected first at 32 weeks of age and the incidence and severity were higher in older animals, all of the mice being affected after 58 weeks of age. Ultrastructurally, the inclusions appeared as sheaves of parallel osmiophilic filaments in the perikaryon of the neurons in the thalamus. Thus thalamic neuronal inclusions in mice seem to be age-related, but their significance remains unclear.

Aging↗
PubMed1995

Subclinical renal oxalosis in wild-caught Japanese macaques (Macaca fuscata).

Various degrees of crystal deposition were found in the kidneys of 12 out of 59 Japanese macaques (Macaca fuscata) caught in the wild in Gifu, Japan. The needle- or rod-shaped crystals, which were radially arranged and occurred in the lumen and epithelium of the renal (mainly the proximal) tubules, were birefringent under polarized light. They stained with alizarin red S at a pH of 7.0 but not 4.2, and were identified as calcium oxalate. The morphological features of the renal lesions were similar to those previously reported in oxalate poisoning, and it was believed that the macaques ingested the oxalate in plants.

Animals↗
PubMed1995

Characterization of a novel human tumor necrosis factor-alpha mutant with increased cytotoxic activity.

Various novel recombinant human tumor necrosis factor-alpha (TNF) mutants were prepared using protein engineering techniques, and their cytotoxic activity was compared with that of the intact form of TNF (intact TNF). Mutant 471 (a TNF mutant molecule with the deletion of 7 amino acids at the amino-terminal and the substitution of Pro8Ser9Asp10 by ArgLysArg) had a 6-fold higher cytotoxic activity against murine L929 cells. The mutant TNF had an increased ability to bind to TNF receptor on murine L929 fibroblasts cells. A cross-linking study revealed that mutant 471 had an increased ability to form an active trimer. Mutant 471 also showed higher cytotoxic activity against human KYM myosarcoma cells and human MIA PaCa-2 pancreatic carcinoma cells. The possible cachectin activity of the mutant was almost the same as that of intact TNF. These results suggest that mutant 471 might be a more promising candidate as an anticancer agent than intact TNF.

Amino Acid Sequence↗
PubMed1995

Basal cell tumor in a Japanese macaque (Macaca fuscata).

A rare case of basal cell tumor of the skin in a wild-caught female Japanese macaque (Macaca fuscata) was studied. Tumor growth, which was composed of cells resembling basal cells, was observed in the dermis and subcutis and showed a mixture of ribbon, solid, glandular, and cystic patterns. The tumor was separated from surrounding normal tissue by a compressed zone of fibrous connective tissue. The nuclei were round and hyperchromatic and possessed a single centrally located nucleolus. Mitotic figures were common. Immunohistochemically, a positive reaction for epithelial membrane antigen, keratin, and cytokeratin AE3 was evident. Electron microscopic examination revealed a small number of tonofilaments in the cytoplasm.

Animals↗
PubMed1995

Histopathologic features of naturally occurring hepatozoonosis in wild martens (Martes melampus) in Japan.

Nodular lesions containing Hepatozoon sp. schizonts or merozoite-gametocytes were found in the tissues of 67 (96%) of 70 wild-caught martens (Martes melampus) examined in Gifu, Japan, 1991 and 1992. The heart was the most commonly parasitized organ (96%), followed by the perirenal adipose tissue (36%); the diaphragm, mesentery, tongue, omentum and perisplenic adipose tissue generally had a prevalence of 10 to 15%. In the heart, two types of nodular lesions were differentiated based on developmental stages: nodules containing schizonts and nodules consisting of an accumulation of phagocytes containing merozoites or gamonts. Under electron microscopy, mature schizonts contained membrane-bound merozoites with a single nucleus and small scattered electron-dense cytoplasmic granules in the schizont nodules; the merozoites and gamonts were engulfed in a phagosome-like vacuole of phagocytes with the nucleus compressed to one side due to the parasite in the merozoite-gamont nodule.

Adipose Tissue↗
PubMed1994

Polyglucosan bodies in the brain of a cow.

Polyglucosan bodies (PGBs) in the brain of a 12-year-old Holstein cow exhibiting no signs of neurological abnormality were examined by light and electron microscopy and immunohistochemistry. PGBs were disseminated throughout the brain, especially in the pallidum, thalamus and cerebellum. Cow PGBs were found in the neuronal perikaryon and in the neuropil. These were round, slightly to severely basophilic, and were strongly positive for the periodic acid-Schiff reaction. The cow PGBs were immunoreactive for monoclonal antibodies raised against human polyglucosan. Electron microscopic analysis revealed that they were composed of branching filaments, glycogen granules and electron-dense material. These findings indicate that cow PGBs closely resemble human or canine PGBs in Lafora's disease and PGBs found in aged animals that have been reported previously.

Animals↗
PubMed1994

Spontaneous vascular mineralization in the brains of cows.

The frequency of occurrence and the characteristics of vascular mineralization in the brains of cows were studied. Mineralized lesions were found in the pallidal arteries in eight of 13 cows. They appeared as basophilic deposits in the arterial walls, were sheath-like or tubular in shape, and were accompanied by intimal oedema or fibrous thickening. The deposits were positive for periodic acid-Schiff, von Kossa's, alizarin red and Berlin blue stains. Elemental analysis revealed the presence of large amounts of phosphorus, calcium and zinc, as well as small amounts of iron, copper and sodium.

Animals↗
PubMed1994

Spontaneous aortic arteriosclerosis in layer chickens.

Aortas of 21 grower chickens (both sexes) aged 30-130 days and of 51 layer hens aged 500 days were examined histopathologically. Aortic sclerotic lesions were classified histopathologically into six stages. As early as 30 days, the abdominal aortas of growers had cellular-fibrous plaques that became more severe with advancing age. The majority of the abdominal aortas of all the 500-day-old layers had a conspicuous increase of collagen fibres, with atheromatous lesions in 23 (45.1%). These sclerotic changes were most severe in the distal aortas.

Animals↗
PubMed1994

Adenocarcinoma in the rectum of a capped langur (Presbytis pileata).

A rectal adenocarcinoma in a 22-year-old capped langur histologically resembling those in human cases is reported. An ill-defined diffuse tumor with fibrously firm rectal wall showed diffuse infiltrative growth of signet-ring cancer cells. Immunohistochemistry demonstrated positive staining for CEA, lysozyme, EMA, keratin and B72.3.

Animals↗
PubMed1994

Vascular mineralization in the monkey brain.

Mineralization of various degrees was found in the brains of 79 (59%) of 134 cynomolgus monkeys (Macaca fascicularis). There was no age dependency in the incidence or severity, nor were there any abnormalities in growth, weight gain, or neurologic signs, although a slight sex difference was observed. The lesions, which were basophilic and intensely positive for periodic acid-Schiff or von Kossa stain, occurred in the vascular walls of the globus pallidus in two types: globoid bodies with prominent concentric lamellar structures in and around the arteriolar and venular wall (type A) and fine granules in the media of small or medium-sized arteries (type B). Electron microscopic examination revealed dense deposits in the degenerated media of small or medium-sized arteries or the thickened walls of the arterioles. X-ray microanalysis demonstrated the presence of calcium, phosphorus, iron, zinc, magnesium, and aluminum.

Animals↗
PubMed1994

Ameloblastic fibro-odontoma in the mandibular incisor of a cow.

Odontogenic neoplasm was found in the mandibular incisor area of a 3-year-old Japanese black ox. Macroscopically, the cut surface was white and firm with streaks of hard tissue. Histologically, the tumor was composed of enamel organ structures with odontogenic hard tissue in fibromatous areas. It was diagnosed as ameloblastic fibro-odontoma. The absence of the 4th permanent incisor confirmed by radiography and microscopic examination strongly suggests that this tumor has been originated from the tooth germ tissues of the permanent left 4th incisor.

Animals↗
PubMed1994

Gastric adenocarcinoma in a cougar (Felis concolor).

Diffusely invasive tumors occurred in the stomach of a 9-year-old female cougar (Felis concolor) from a zoo in Japan. The tumors consisted of tubular adenocarcinoma cells, and had infiltrative growth to the submucosa and muscularis propria. Tumor cells were positive for carcinoembryonic antigen (CEA), lysozyme, epithelial membrane antigen (EMA), gastrin, alpha-1-fetoprotein (AFP), keratin, and B72.3. Mucin-like materials occurred within cytoplasmic vacuoles.

Adenocarcinoma↗
PubMed1994

Hypertrophic pulmonary osteoarthropathy in a raccoon dog (Nyctereutes procyonoides) with chronic pulmonary inflammatory lesions.

A female raccoon dog (Nyctereutes procyonoides) captured September 1992 in Nara prefecture, Japan, suffering from swollen joints of all four limbs was necropsied. Radiographically, there was a shadow in the right pulmonary caudal lobe and periosteal bone formation around several joints. Microscopically, there was extensive edema, along with one large and many small pyogranulomatous nodules and purulent bronchitis in the right lobe and left caudal lobe of the lungs. There were intermingled branching filamentous bacteria in the lesion, which stained positively with Warthin-Starry, Grocott, and Gram stains, and partially with periodic acid Schiff and Ziehl-Neelsen stains. Extensive exostosis with coralloid trabeculation had developed bilaterally at the carpal, stifle and hock joints in the surrounding well vascularized loose connective tissue. Degeneration of articular cartilage and villous proliferation of synovial membranes were apparent. This is the first report of hypertrophic pulmonary osteoarthropathy in the raccoon dog.

Animals↗
PubMed1993

Spontaneous globoid mineralization in the cerebellum of rats.

Cerebellar globoid mineralization in two rats was examined by light and electron microscopy, and by X-ray microanalysis. The mineralization was round to oval in shape; it varied in size and was positive for the periodic acid-Schiff and von Kossa reactions. Ultrastructurally, a concentric lamellar structure was prominent in moderately electron-dense depositions. Elemental analysis revealed the presence of large amounts of calcium and phosphorus, and small amounts of zinc, potassium and aluminum.

Animals↗
PubMed1993

Lysosome labilizers potentiate the antitumor effects of tumor necrosis factor-alpha.

Enhancement of in vitro cytotoxic activity of tumor necrosis factor-alpha (TNF-alpha) was observed in combination with lysosome labilizers, particularly with urokinase-type plasminogen activator (u-PA), tissue-type plasminogen activator (t-PA) and lipoprotein lipase (LPL). The concentration of TNF-alpha resulting in 50% cytotoxicity to L929 cells was only 20-30% of the value for TNF-alpha alone, when used in combination with a nontoxic dose of u-PA, t-PA or LPL. Furthermore, combined intravenous (i.v.) administration of TNF-alpha (3.5 x 10(5) U/mouse) and u-PA (300 IU/mouse) markedly increased the in vivo antitumor activity of TNF-alpha to Meth A tumors transplanted into BALB/c mice; the tumor weight in co-administered mice was about 40% of that in mice given TNF-alpha alone on day 6. The combination therapy of TNF-alpha (7.0 x 10(4) U/mouse, i.v.) and u-PA (300 IU/mouse, i.v.) was also effective for L929 tumors in Crj:CD-1(1CR)-nu nude mice compared with the conventional therapy with TNF-alpha alone. These results suggest that the combination of TNF-alpha and lysosome labilizers is a promising antitumor therapeutic regimen with clinical potential.

Animals↗