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Biomedical subjects

A Shimada

Publications and source records attributed to A Shimada.

351 records · Page 20Linked to original sources
PubMedDate not supplied

Congenital spongiform change in the brain stem nuclei of a domestic kitten.

This report describes a novel spongiform change in the brain stem nuclei of a 9-month-old mixed breed kitten with neurological signs. Histologically, vacuoles were found in perineuronal spaces and neuropil, with mild to moderate astrocytosis in the brain stem nuclei. Vacuoles were not observed in the cytoplasm of neurons and no evidence of neuronal loss was found. Ultrastructurally, there were intramyelinic vacuoles with separation of lamellae at intraperiod lines and larger spaces formed by coalescence of ruptured vacuoles. Immunohistochemically, abnormal accumulation of prion protein (PrP) was not detected in the brain stem lesions. This is, to our knowledge, the first report of a feline spongiform change localized in the brain stem nuclei.

Animals↗
PubMedDate not supplied

Immunohistochemical and ultrastructural studies of 2,6-dimethylaniline-induced nasal proliferative lesions in a rat two-stage nasal carcinogenesis model initiated with N-bis(2-hydroxypropyl)nitrosamine.

Proliferative lesions induced by 2,6-dimethylaniline (DMA) in a two-stage rat nasal carcinogenesis model were immunohistochemically and ultrastructurally investigated. Male F344 rats received diet containing 3,000 ppm DMA for 52 weeks after initiation with a single subcutaneous injection of 2400 mg/kg of N-bis(2-hydroxypropyl)nitrosamine (DHPN). Histopathologically, proliferation of Bowman's glands, glandular hyperplasias, dysplastic foci, adenomas, and carcinomas were observed in treated rats. These nasal lesions mostly arose in the olfactory mucosa of the nasal cavity. Immunohistochemically, they were positive for cytokeratin and/or collagen type IV antibodies. Ultrastructurally, intracytoplasmic dense secretory granules (200-850 nm in diameter), identical to those in normal Bowman's glands, were observed in all the lesions, providing further support from an origin from these glands. Based on their cellular characterization, growth pattern and/or proliferative activity, two morphological continua were evident, one from dysplastic foci to carcinomas and the other from proliferation of Bowman's glands to glandular hyperplasias and adenomas. These results suggest that dysplastic foci arise from Bowman's glands and progress to carcinomas, while proliferation of Bowman's glands result in glandular hyperplasias and adenomas.

Adenoma↗
PubMedDate not supplied

Ceroid-lipofuscinosis (Batten's disease): pathogenesis and sequential neuropathological changes in the ovine model.

A sequential morphological study of ovine ceroid-lipofuscinosis showed that brains of affected lambs were normal at birth, grew until four months of age but then atrophied. Laminar necrosis of cerebral cortex was noted at 10 weeks, occurring first in the parietal area, then spreading to involve frontal and occipital areas while the temporal lobe was least and last affected. With progression of the disease, the laminar pattern was lost. Neuronal necrosis was accompanied by a severe astrocytosis. The granular and multilamellar storage cytosomes increased in size with age. Their structure was interpreted as paracrystalline in which repeating molecules of the dominantly stored lipid binding subunit of mitochondrial ATP synthase interact with neutral lipids and phospholipids. Abnormal cytosomes in neurons of lamb fetuses and a neonate were interpreted as early lesions which contained whorls or stacks of bilayered membrane as well as the more complex multilamellar material. The underlying anomaly leading to the storage of the lipid binding subunit of mitochondrial ATPsynthase remains to be defined. However, it is noted that this disease should be regarded as a lipid binding protein proteinosis or alternatively as a proteolipid proteinosis.

Age Factors↗
PubMedDate not supplied

Desmoplastic response in scirrhous gastric carcinoma: imbalance between collagen synthesis and degradation.

BACKGROUND: Scirrhous gastric carcinoma is characterized by a marked deposition of collagen in the stroma and has a very poor prognosis. MATERIALS AND METHODS: To elucidate the fibrotic mechanism in scirrhous gastric carcinoma, we measured the activities of the collagen synthetic enzyme, prolyl 4-hydroxylase (P4H) and the collagen degrading enzymes, interstitial collagenase and type IV collagenase, in tissue from patients with advanced gastric carcinoma. Concentrations of P4H and tissue inhibitor of metalloproteinases-1 (TIMP-1) in the sera of patients with gastric carcinoma were measured using sandwich enzyme immunoassay systems. We performed immunohistochemical analysis for TIMP-1. RESULTS: Enzyme activities of P4H, interstitial collagenase and type IV collagenase in the tumor samples of scirrhous gastric carcinoma were significantly lower than those of non-scirrhous gastric carcinoma (p < 0.01). Serum concentration of TIMP-1 in patients with diffuse type carcinoma was significantly higher than in patients with intestinal type carcinoma and control subjects (p < 0.05). We demonstrated stromal expression of TIMP-1 in scirrhous gastric carcinoma tissue. CONCLUSION: These data suggest that decreased collagenase activity and increased expression of TIMP-1 would result in collagen deposition in scirrhous gastric carcinoma tissue.

Adenocarcinoma, Scirrhous↗
PubMedDate not supplied

Gentamicin nephrotoxicity: application of multivariate analysis.

A retrospective study was conducted to identify patient risk factors associated with gentamicin nephrotoxicity using multivariate analysis. Patients were evaluated for nephrotoxicity using an algorithm that considers serum creatinine, previous general experience with the drug, alternative etiologic candidates, timing of events, drug concentrations or evidence of overdosage, dechallenge, and rechallenge. There were 220 patients who met the criteria for inclusion in the study (103 men and 117 women). Variables found not to be significant discriminators between toxic and nontoxic patients included height, weight, sex, dose, estimated peak gentamicin concentration, age, and initial renal function. Variables that were found to enter into the discriminant analysis included presence of complicating factors with nephrotoxic potential, number of concurrent potentially nephrotoxic drugs, intensity index or estimated trough gentamicin concentration, and the total dose or treatment duration. Two models were developed; the probability of correctly classifying a patient as toxic was 63.5% and 65.4%, and as nontoxic was 72.1% and 68.8% for the two models, respectively. Although the discriminant models developed were statistically significant, the discrimination between toxic and nontoxic patients was not satisfactory to allow development of a generalized predictive model. Multivariate techniques were found to be essential in allowing for the differentiation of variables causing gentamicin nephrotoxicity.

Adult↗
PubMedDate not supplied

Usefulness of fecal alpha-1-antitrypsin for detection of gastrointestinal bleeding in patients with gastric cancer.

Hemoglobin (Hb), albumin (Alb), immunoglobulin G (IgG) and alpha-1-antitrypsin (AAT) were measured in 87 fecal samples from 29 normal volunteers and 68 fecal samples from 33 patients with gastric cancer before surgery to evaluate the usefulness of fecal AAT as an indicator of gastrointestinal bleeding in patients with gastric cancer. Mean values and standard deviation of fecal Hb, Alb, IgG and AAT in normal volunteers were 0.13 +/- 1.19 micrograms/g, 6.96 +/- 20.48 micrograms/g, 17.52 +/- 10.16 micrograms/g, and 0.483 +/- 0.315 mg/g, respectively. These parameters in the patients with gastric cancer were significantly higher than those in the normal volunteers. No statistically significant correlations were observed between these fecal parameters, except between fecal Alb and IgG. Data obtained from peripheral blood also showed no significant correlation with these fecal parameters. When the cut-off levels of fecal Hb, Alb, IgG and AAT were set at M + 2SD of the values obtained from the normal volunteers, sensitivity, specificity and accuracy were 80.0%, 86.2% and 84.1% for fecal AAT, and 66.7%, 96.6% and 86.4% for fecal Hb in the patients with advanced gastric cancer in a cohort consisting of patients with advanced gastric carcinoma and normal volunteers. Since fecal AAT showed higher sensitivity in patients with advanced gastric cancer with a low number of false negative cases, we concluded that measurement of fecal AAT could be a promising method for assessment of gastrointestinal bleeding in patients with advanced gastric carcinoma instead of immunological detection of fecal Hb.

Feces↗
PubMedDate not supplied

A study of discoloration of the gingiva by artificial crowns.

In this study, soft tissue discoloration including the marginal gingiva, gingival papilla, and attached gingiva were evaluated in subjects with artificial crowns and compared to the soft tissue of natural teeth using a spectrophotometer. Gingivae around artificial crowns had a lower value (L*) and chroma (C*ab) than the gingivae surrounding natural teeth. Hue (Hab o) shifts toward red-purple were frequently noted. There was generally a more noticeable color difference (E*ab) in the marginal gingiva and gingival papilla of teeth with crowns than was found in the attached tissue.

Adult↗