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Biomedical subjects

C Itakura

Publications and source records attributed to C Itakura.

At least 19 recordsLinked to original sources
PubMed2000

Ganglion cysts in a juvenile dog.

Ganglion cysts were diagnosed in a 4-month-old male Afghan Hound. Grossly, the subcutaneous ovoid cysts around the caudal right elbow joint and left ischiatic tuberosity had abundant mucinous fluid and internal folding. The lesions recurred twice around the elbow joint after surgical removal. Neither cyst communicated with the joint cavity. Histologically, the cyst wall consisted of inner myxomatous and outer immature connective tissue. Some parts of the cyst wall had various stages of myxoid metaplasia of collagen tissue leading to new cyst formation. Ultrastructural study revealed that cells in the myxoid metaplastic lesion had well-developed cytoplasmic secretory elements, including abundant rough endoplasmic reticulum, Golgi apparatus, and many smooth-walled vesicles. These ganglion cysts apparently resulted from the metaplasia of fibroblasts to secreting cells.

Animals↗
PubMed1999

Distal axonopathy does not occur without neurofilament accumulation in gamma-diketone neuropathy: comparative studies of normal and neurofilament-deficient quail.

The neurotoxic effects caused by chronic exposure to 2,5-hexanedione (2,5-HD) were investigated in normal and neurofilament (NF)-deficient quail (Quv strain). These quail were given 175 mg/kg per day of 2,5-HD intraperitoneally for 24 weeks. Five of nine normal quail showed clumsy gait. They had NF-rich axonal swellings in the distal parts of the peripheral nerves, ventral and lateral funiculus of the cervical cord, and cerebellar peduncles. Axonal degeneration consisting of accumulation of mitochondria, vesicles, microtubules and dense bodies was found distal to the axonal swellings. Testicular atrophy appeared in two normal quail. In contrast, four of nine Quv quail showed systemic tonic convulsion, and died of respiratory paralysis within 6 days. No significant changes in the nervous system or testis of these four dead Quv quail. The five other Quv quail survived and did not show any neurological signs. Again, no significant changes were detected in the nervous system or testis of the surviving Quv quail. The present study revealed that distal axonal degeneration did not occur without NF accumulation. These results suggest that NF accumulation is an essential factor in the development of distal axonopathy in gamma-diketone neuropathy.

Animals↗
PubMed1999

Hepatic lesions in young rabbits experimentally infected with rabbit haemorrhagic disease virus.

Twenty young rabbits (eleven 2-week-old and nine 4-week-old) were experimentally infected with rabbit haemorrhagic disease virus (RHDV) to clarify susceptibility. They were killed chronologically up to 96 hours post-inoculation (PI) and examined for lesions. All inoculated rabbits were clinically normal, but grossly minute white or grey spots were detected throughout the liver. Histologically, the lesions consisted of aggregates of lymphocytes, macrophages and heterophils, with or without acidophilic bodies and necrotic hepatocytes. Immunohistochemically, RHDV antigens were found in the degenerated hepatocytes and in macrophages. The cellular aggregates were considered to be a reaction to necrotic hepatocytes infected with RHDV. It was concluded that some hepatocytes are susceptible to RHDV in young rabbits.

Animals↗
PubMed1999

Analysis of transcriptional and translational activities of Marek's disease (MD) virus genes in MD central nervous system lesions in chickens.

The expression of Marek's disease virus (MDV) gene products and transcripts was observed in tissues obtained from the central nervous system (CNS) of chickens experimentally infected with a very virulent strain (Md/5) of MDV. Many cells antigen-positive for MDV early gene products, but not for late gene products, were detected immunohistochemically in the necrotizing lymphomatous lesions. The positive signals were found only in necrotic or degenerated neoplastic lymphoblasts. Abundant transcriptional activity of MDV genes was observed in the necrotizing lymphomatous lesions for immediate-early and early genes, but not for late ones, by the reverse-transcription polymerase chain reaction. In the non-necrotizing lymphomatous lesions, as well as non-suppurative ones, there were no or very few antigen-positive lymphoblasts for early and late genes, and little transcriptional activity of MDV genes. The necrotizing lesions of the lymphoma were associated with necrotizing vasculitis in which endothelial cells exhibited up-regulation of MHC class II antigen but no viral antigens. The present results indicate that only necrotizing lymphomatous lesions revealed abundant incomplete cytolytic cycle in MDV latently infected neoplastic lymphoblasts.

Journal Article↗
PubMed1999

Lead poisoning in wild waterfowl in Japan.

We collected 430 harvested ducks (Anas sp. and Aythya sp.) from nine prefectures in Japan between 1994 and 1997. Fifteen (4%) of 363 birds harvested during and after hunting seasons had one lead pellet each in the proventriculus and gizzard. In addition, 32 (34%) of 93 swans (Cygnus sp.) and two of 14 geese (Anser sp.) found dead from various wetlands had lesions consistent with lead poisoning. One to nine swans suspected of having toxicosis from ingestion of lead shot were found dead each year. Twenty-seven (84%) of the 32 lead-exposured swans were found in Hokkaido Prefecture. We concluded that lead poisoning is still a serious threat to waterfowl in Japan and that there is considerable need for environmental improvement concerning this problem.

Animals↗
PubMed1998

Bronchiolar-alveolar carcinoma in a cow.

Bronchiolar-alveolar carcinoma was observed in the lung of an 8-year-old Holstein cow. Grossly, the lung contained multiple tumour masses, which were solid, yellowish-white in colour, and firm in consistency. These tumours also occurred in the liver, pancreas, uterus and lymph nodes in the thoracic, abdominal and pelvic cavities. Histologically, the masses were composed of abundant fibrous stroma and proliferating atypical cuboidal epithelial cells, occasionally forming glandular structures. Electron microscopy revealed that the neoplastic cells had microvilli and lamellar bodies in the cytoplasm, suggesting that they originated from immature respiratory epithelial cells differentiating towards either Clara cells or type II pneumocytes.

Adenocarcinoma, Bronchiolo-Alveolar↗
PubMed1998

Cytology of feather pulp lesions from Marek's disease (MD) virus-infected chickens and its application for diagnosis and prediction of MD.

Cytological changes of feather pulp lesions (FPL) sampled chronologically from the same specific-pathogen free chickens inoculated with Marek's disease virus serotype 1 (MDV) were examined, comparing with their histological changes. The birds having Marek's disease (MD) lymphomas or nerve lesions exhibited the characteristic lesion changes on the cytological smears of FPL; the initial non-suppurative inflammatory to the late lymphomatous FPL. The birds having neither the MD visceral lymphomas nor the nerve lesions manifested only non-suppurative inflammatory FPL on the cytological smears throughout the experimental periods. Histological evaluation of FPL sampled from the same birds confirmed as above mentioned cytological results. From these results, the cytological evaluation of FPL proved to be an effective diagnostic and prognostic tool in foreseeing MD incidence.

Animals↗
PubMed1997

Apocrine gland tumor of the eyelid in a dog.

A 13-year-old male Shetland Sheepdog with progressive exophthalmos had a neoplastic mass in the ocular adnexa. Histologically, this neoplasm was composed of duct-forming epithelial cells with decapitation secretion. Tumor cells invaded the globe through the tunica conjunctiva and replaced the vitreous body. The cornea, iris, ciliary body, and retina were extensively destroyed. Both the epithelial and spindle-shaped myoepithelial cells showed nuclear atypia and mitotic activity in the globe. The primary tumor was diagnosed as adenocarcinoma, probably originating from apocrine sweat glands of the eyelid, and the infiltrating intraocular neoplasm was diagnosed as a malignant mixed tumor.

Adenocarcinoma↗
PubMed1997

Hantavirus infection in SCID mice.

Severe combined immunodeficiency (SCID) mice were inoculated with Hantaan virus strain 76-118 (HTN) or Seoul virus strain SR-11 (SR) of hantaviruses. Susceptibility of SCID mice was compared with those of immunocompetent adult mice, newborn mice and nude mice. SCID mice inoculated with HTN or SR died 32 to 35 days after infection. Unlike newborn mice which also died of hantavirus infection, SCID mice survived longer than newborn mice and showed typical wasting symptoms rather than nervous symptoms. Immunohistochemical staining and virus isolation indicated that both HTN and SR inoculated SCID and SR inoculated nude mice showed systemic infection, but nude mice inoculated with SR survived for longer than 8 weeks after inoculation. Passive transfer of spleen cells from immunocompetent BALB/c mice conferred protection on SCID mice within 2 weeks of HTN infection. Immune mediated pathologic mechanism was examined by transferring the spleen cells to SCID mice inoculated with HTN virus 3 weeks before the cell transfer. The recipient SCID mice showed an increase of serum BUN level coinciding with the appearance of serum antibody to HTN virus, suggesting the immune mediated pathogenicity.

Adoptive Transfer↗
PubMed1996

Regeneration of myelinated fiber after crush injury is retarded in sciatic nerves of mutant Japanese quails deficient in neurofilaments.

Regeneration of myelinated fibers in the sciatic nerve 2 weeks after crush injury was studied morphometrically in mutant Japanese quails deficient in neurofilaments and in normal quails (controls). There were fewer regenerated myelinated fibers per nerve at 10 mm (R1) and 20 mm (R2) distal to the crush site in mutants than in controls (P < 0.05). Both median and maximum diameters were smaller (P < 0.01) in mutants than in controls. On electron microscopy, transverse axonal area and axonal circumference were smaller (P < 0.001) at both R1 and R2 in mutants than in controls. The number of myelin lamellae was less (P < 0.01) in mutants than in controls at R1, but was similar at R2. There were fewer myelin lamellae in relation to axonal area in mutants than in controls at R1 (P < 0.0001) and R2 (P = 0.0032). The results indicate a retardation of both radial growth of axons and myelination around axons of the same size in mutants compared with controls. Such retardation may be explained by the deficiency of neurofilaments and the altered relationship between Schwann cell and axon in the mutant.

Animals↗
PubMed1996

Changes of GTP binding proteins, not neurofilament-associated proteins, in the brain of the neurofilament-deficient quail, "Quiver".

A neurofilament (NF)-deficient mutant of the Japanese quail was named "Quiver", as it showed generalized quivering as a clinical sign. NF consists of three major subunits; low, middle and high. We previously reported that the noradrenaline and 5-hydroxytryptamine content in the neostriatum of the Quiver's brain was different from that in the normal quail, although disappearance of the three NF proteins occurred in all areas of the Quiver's brain. Thus, NF-related proteins may show considerable changes in the specific sites of Quiver's brain. In this study, an examination was made of the changes in NF-related proteins in the Quiver, by immunoblotting analysis. The amounts of cyclin-dependent kinase 5 (cdk5), which phosphorylates NF proteins, and tau which is a substrate of cdk5, in the neostriatum of the Quiver, were essentially the same as those in the normal quail, although NF proteins could not be detected in the Quiver. The amount of alpha-tubulin in the Quiver's brain was similar to that in the normal quail. Next, we investigated the changes of GTP binding (G) proteins in the Quiver's brain, because cytoskeletal components such as tubulin and F-actin bind with G proteins. [32P]ADP-ribosylation of G proteins (Gs by cholera toxin and Gi/G0 by pertussis toxin) in the neostriatum of the Quiver increased significantly, although alpha subunits of G proteins showed no change by immunoblotting analysis. The ratios of the trimer form in G proteins thus appear to increase more in the NF-deficient Quiver brain than in the brain of the normal quail. The G proteins-mediated adenylate cyclase activities were the same in the brain of both the Quiver and the normal quail. Possible interactions between NFs and G proteins are discussed.

Adenosine Diphosphate Ribose↗
PubMed1996

Fibromuscular dysplasia in intramuscular arteries of Japanese quail (Coturnix coturnix japonica).

Fibromuscular dysplasia (FMD) was found in the intramuscular arteries of both commercial (normal) and mutant (LWC) strains of Japanese quail. The mutant strain LWC is afflicted with an inherited muscular dystrophy exhibiting myotonia. The arterial lesions were classified as medial fibroplasia or medial hyperplasia, both being subtypes of medial FMD. Some lesions showed extensive proliferation of medial smooth muscle into the vascular lumen, resulting in partial occlusion of the affected blood vessel. FMD occurred more frequently in the mutant LWC quail than in the commercial strain. Ischaemic changes were absent in the associated muscle structures in both strains. The significance of FMD in relation to the skeletal muscle changes in the mutant LWC strain remains unclear.

Animals↗
PubMed1996

Neuropathological studies of chickens infected with highly pathogenic avian influenza viruses.

Central nervous system lesions of chickens inoculated with three highly pathogenic avian influenza virus strains, A/chicken/Victoria/1/85 (H7N7), A/turkey/England/50-92/91 (H5N1), and A/tern/South Africa/61 (H5N3), were examined histologically and immunohistochemically. The chickens either died within 7 days of inoculation or were killed 2 weeks after inoculation. No significant differences were observed in the lesions induced by these three viruses. The lesions were divided into two types, disseminated foci of microgliosis and necrosis, and ventriculitis. The former lesions were associated with infection of the vascular endothelium and dissemination of the virus to the peripheral parenchymal cells of the chickens that died within 3 days of inoculation. The ventriculitis lesions, however, were observed mainly in the chickens that died between 4 and 7 days after inoculation. These findings suggest that viral infection of the vascular endothelium and subsequent involvement of ependymal cells play important roles in the pathogenesis of the central nervous system lesions.

Animals↗
PubMed1996

Inherited muscular disorder in mutant Japanese quail (Coturnix coturnix japonica): an immunohistochemical study.

Cryostat sections of myofibres from the Musculus pectoralis thoracicus of a newly established mutant strain (LWC) of Japanese quail with a myotonic dystrophy-like myopathy were labelled with antibody against myosin heavy chain (MHC) isoforms and neural cell adhesion molecule (N-CAM). The characteristic lesions found in sections of muscle of LWC quail stained with haematoxylin and eosin were type 2B fibre atrophy, sarcoplasmic masses, and ring fibres. Immunohistochemical examination failed to distinguish type 2A and 2B fibres in the LWC quail. Antibody to adult fast MHC, which reacted only with type 2A fibres in normal quail, reacted in LWC quail with type 2B fibres, and to a limited degree with type 2A fibres. Sarcoplasmic masses reacted with both fast and slow MHC antibodies. Some masses also reacted with NCAM antibody, but apparently independently of similar reactions in fibres. These findings suggest that the changes observed in the myofibres of the LWC quail were not neurogenic but represented defects in both the plasma membrane and intermediate filaments.

Animals↗
PubMed1996

Inherited muscular disorder in mutant Japanese quail (Coturnix coturnix japonica): an ultrastructural study.

Ultrastructural study of muscles taken from a mutant (LWC) strain of Japanese quail with myotonia showed type 2 fibre atrophy, ring fibre formation, sarcoplasmic masses, and "moth-eaten" fibres. In these abnormal fibres, the most characteristic feature was the loss of interconnection among the myofibrils, mitochondria, and T tubules. Apparently normal muscle fibres often showed mild changes, such as proliferation of T tubules and enlarged sarcoplasmic areas with increased glycogen granules and ribosomes at the periphery of the fibres. The study suggested that one possible cause of these ultrastructural changes was a defect in cytoskeleton of muscle cells, especially in intermediate filaments.

Animals↗
PubMed1996

Life span and tumours in the first-generation offspring of the gamma-irradiated male mouse.

C57BL/6 male mice were exposed to 3 Gy 60Co gamma-rays and mated with unirradiated females after 15 days to produce F1 progeny produced following irradiation of the spermatids. After weaning the offsprings were allowed to live their normal life span. The mean litter size of the irradiated group significantly decreased from 7.1 to 4.9 (p < 0.01), but the sex ratio was not altered by the irradiation. No significant differences in the survival curve and mean life-span between the irradiated and control groups were noted. The only radiation effect in tumour incidence was a decrease of histiocytic sarcoma in female offspring of irradiated males. Except for this, there were no significant differences between the irradiated group and the control group in the incidence or age distribution of tumours.

Animals↗
PubMed1996

Age-related changes in the olfactory system of dogs.

Age-related changes in the olfactory system were examined in 22 dogs ranging in age from 10 to 19 years old. Atrophic changes with degeneration were observed in the olfactory epithelium of dogs older than 14 years; the changes were prominent in the dogs over the age of 17 years. Immunohistochemistry using an anti-carnosine antibody, which is a marker for the olfactory cells, demonstrated a decrease in the number of olfactory cells. Electron microscopy also showed a decrease in the number of cilia of olfactory cells and microvilli of supporting cells. Atrophic changes with the features of regeneration were rarely observed in the aged animals. Lipofuscin-like granules in the olfactory epithelium became prominent with age. These age-related changes were similar to those reported in the olfactory epithelium of man and rats. Dystrophic neurites were not detected by a modified Bielschowsky stain or by neurofilament, synaptophysin and tau immunohistochemistry in the olfactory mucosa. There was no beta-amyloid- and ubiquitin-immunostaining in the olfactory mucosa. Senile brain changes, including cerebrovascular amyloidosis, age-related astrocytic gliosis and ubiquitin deposits were found in the olfactory bulb, although neurofibrillary tangles and senile plaques were not detected either by a modified Bielschowsky stain or by beta-amyloid immunohistochemistry. These results indicate that dog may be a useful animal model to study the age-related changes in the olfactory system in man.

Age Factors↗