PubMed Health⌕ Search

Biomedical subjects

N Nakahara

Publications and source records attributed to N Nakahara.

At least 19 recordsLinked to original sources
PubMed1995

[Magnetic resonance imaging of sacral insufficiency fractures: characteristic features and differentiation from sacral metastasis].

Seven patients with sacral insufficiency fractures and seven patients with sacral metastasis were studied with MR imaging. The diagnoses were confirmed with other imaging modalities and clinical follow-up. The insufficiency fractures appeared as bands of abnormal signal: low signal intensity on T1-weighted images and slightly low to iso signal intensity on T2-weighted images. The lesions were delineated better on T1-weighted images than on T2-weighted images. The sacral alae were involved in all patients; five patients had bilateral lesions. The lesions that run across the sacral body were seen in three cases. Inclined coronal images were useful in demonstrating the pattern of distribution of the sacral insufficiency fractures. In three patients with follow-up MR studies, the lesions were markedly reduced or disappeared. The sacral metastatic tumors were of low signal in density on T1-weighted images and iso to high signal in density on T2-weighted images. The extent and distribution patterns of the lesions were various. It is possible to differentiate sacral insufficiency fractures from sacral metastases based on their distribution patterns on MRI. However, if the diagnosis is uncertain or if the symptoms persist or become worse, follow-up MR studies may be necessary.

Aged↗
PubMed1991

Lymphocytic adenohypophysitis: an immunohistochemical study.

Lymphocytic adenohypophysitis is a rare inflammatory disorder of the anterior pituitary gland. In some cases, there is evidence of concurrent autoimmune disease. We present the case of a 39-year-old woman who developed visual disturbance during the early postpartum period. Magnetic resonance imaging revealed an intrasellar mass with suprasellar extension. Study of the tumor tissue showed diffuse infiltration of the entire pituitary gland by lymphocytes and plasma cells. Immunohistochemical examination revealed that the majority of the infiltrating lymphocytes were T cells that might have modulated the immunoreaction to the anterior pituitary gland. We suggest that the disorder is related to cell-mediated immunity as well as humoral immunity.

Adult↗
PubMed1990

Central muscarinic activities of an M1-selective agonist: preferential effect on reversal of amnesia.

Effects of FKS-508 (AF102B; cis-2-methylspiro (1,3-oxathiolane-5,3')-quinuclidine), a novel M1-selective agonist, on central muscarinic responses in mice were examined in comparison with oxotremorine. FKS-508 was slightly less potent (6 times) in reversal of scopolamine-induced amnesia (passive avoidance failure), but far less potent (260 and 55 times) in producing hypothermia and tremor than oxotremorine. These results show that the selective M1 agonist FKS-508 differentiates highly between the central muscarinic effects.

Animals↗
PubMed1989

Beneficial effects of FKS-508 (AF102B), a selective M1 agonist, on the impaired working memory in AF64A-treated rats.

The effects of FKS-508 [AF102B; cis-2-methylspiro(1,3-oxathiolane-5,3')quinuclidine], a selective M1 muscarinic receptor agonist, were examined to predict the possible activity on memory disorders using a T-maze and radial-arm maze task in experimental amnesia models. The amnesia models were produced by bilateral intracerebroventricular injection of ethylcholine aziridinium ion (AF64A), a selective cholinotoxin, in rats. Repeated administrations of FKS-508 (5 mg/kg/day, i.p.) for 5 weeks significantly ameliorated impaired performance of AF64A-treated rats (AF64A-rats) in a delayed alternation task in the T-maze. Repeated administrations of FKS-508 (1 and 5 mg/kg/day, p.o.) for 5 weeks significantly ameliorated acquisition failures of AF64A-rats in a radial-arm maze task. Single administration of FKS-508 (1 and 5 mg/kg, p.o.) significantly reduced the incorrect choices of AF64A-rats in a radial-arm maze task with 6 hr-delay time. No abnormalities in general behaviors, such as loss of appetite and ataxia, were observed in rats treated with FKS-508 repeatedly during 5 weeks. Our present results showed that FKS-508 can ameliorate memory impairments in AF64A-rats with central cholinergic hypofunction without causing any behavioral abnormalities. FKS-508 may be considered as a candidate for the clinical examination of the cholinergic hypothesis of senile dementia of the Alzheimer type.

Animals↗
PubMed1989

Chondrosarcoma of the posterior fossa--case report.

The authors describe a case of well differentiated (grade I) chondrosarcoma in a 52-year-old male. The tumor originated in the posteromedial wall of the left petrous bone and extended into the posterior fossa and cervical spine. He showed impaired functions of the left VII to XII cranial nerves. Plain skull x-rays demonstrated erosion of the left petrous and occipital bones, with speckled calcifications. Computed tomography showed a huge mass of slightly high density with mushroom-like calcifications, which was poorly enhanced by contrast medium. Inversion recovery magnetic resonance imaging clearly defined the low-intensity lesion, while the long spin-echo image depicted the tumor as mixed-intensity. On electron microscopic examination, the tumor cells were rich in Golgi apparatus, endoplasmic reticulum, glycogen granules and mitochondria in the cytoplasm, and formed many vacuoles crossing the cell membrane. These vacuoles were suggested to play an important role in matrix formation. Thirty nine other reported cases of chondrosarcoma are reviewed, and the two reported posterior fossa chondrosarcomas are compared with that of ours.

Chondrosarcoma↗
PubMed1989

[Nocardial brain abscess: case report].

A 25-year-old man, who was slightly immunosuppressed, presented headache and right motor weakness due to multiple brain abscesses disseminated from lung abscess. They were diagnosed, by bacteriological examination, as nocardial brain abscesses (nocardia asteroides) 4 weeks after the first operation. In spite of delay in the diagnosis, he was relieved by operations (three times) and chemotherapy including high doses of Sulfamethoxazole-Trimethoprim. He was eventually discharged. We stress the necessity of early diagnosis and the efficacy of Sulfamethoxazole-Trimethoprim for nocardial brain abscess.

Adult↗
PubMed1988

Effects of intracerebroventricular injection of AF64A on learning behaviors in rats.

The effects of intracerebroventricular (ICV) injection of ethylcholine aziridinium ion (AF64A) (3 nmole/2 microliter, each lateral ventricule), a putative selective cholinotoxin, on learning behaviors and choline acetyltransferase (ChAT) activity were studied in rats. AF64A-treated rats (AF64A-rat) exhibited deficient performance in a passive avoidance task and a delayed alternation task in the T-maze, but demonstrated superior avoidance response in a two-way shuttle avoidance task. These changes in learning behaviors were associated with the selective decrease of hippocampal ChAT activity. Physostigmine (0.1 mg/kg, i.p.) significantly improved the retention latency of AF64A-rats in the passive avoidance task. AF64A-rats receiving physostigmine (0.2 mg/kg, i.p.) exhibited a slight but not significant improvement of performance in the delayed alternation task in the T-maze. These findings suggested that ICV injection of AF64A may be useful for producing an experimental amnesia model with hippocampal cholinergic hypofunction like Senile dementia of the Alzheimer type (SDAT), if appropriate learning tests are selected.

Alzheimer Disease↗
PubMed1988

Amelioration of experimental amnesia (passive avoidance failure) in rodents by the selective M1 agonist AF102B.

Effect of AF102B (cis-2-methylspiro-(1,3-oxathiolane-5,3')-quinuclidine) on experimental amnesia was examined using a passive avoidance task in rodents. The amnesia was produced by anti-cholinergic agents, AF64A (intracerebroventricularly) and scopolamine (subcutaneously). AF102B ameliorated the memory deficits in AF64A-treated rats at 0.1-1 mg/kg, i.p. and at 1-5 mg/kg p.o. and in scopolamine-treated mice at 1-10 mg/kg, i.p. These results suggest that AF102B may compensate for central cholinergic defects and could be developed as a possible therapeutic drug for senile dementia of the Alzheimer type.

Amnesia↗
PubMed1986

Morphological and immunological change in the predominant type of leukaemic cells in a patient with T-cell chronic lymphocytic leukaemia.

A case of T-cell chronic lymphocytic leukaemia is described. Intracerebellar tumour was demonstrated by the characteristic feature of contrast-enhanced computerized tomography and was evidenced by surgical procedure. Histological examination revealed lymphocyte infiltration in the cerebellum. Initially, the majority of leukaemic cells were mature, medium-sized lymphocytes with surface marker phenotype of E+, OKT3+, OKT4+, OKT6-, OKT8-. In the terminal stage, large atypical lymphocytes which were morphologically distinct from the original lymphocytes and had different surface marker phenotype of E+, OKT3+, OKT4-, OKT6-, OKT8+, Leu7+ became increasingly prominent. The remaining medium-sized lymphocytes were morphologically and immunologically unchanged. Subsequently, the disease developed to a more aggressive pattern and the patient died in spite of chemotherapy.

Adult↗
PubMed1985

Lateral flagellar antigen of Vibrio alginolyticus and Vibrio harveyi: existence of serovars common to the two species.

The antigenicity of lateral (L-) flagella of two marine vibrios, Vibrio alginolyticus and V. harveyi, was studied, and the two species were found to have common antigenicity of their flagella. Antisera against L-flagella were prepared by immunizing rabbits with highly purified L-flagellar filaments. H-Agglutination tests with the anti-L-flagella antisera showed that four H-serovars existed in these species and that two of them were shared by the two species. Cross reactivity between H-serovars of these two species and other vibrios having lateral flagella, such as V. parahaemolyticus, V. campbellii, V. proteus, or V. fluvialis, was not observed in the H-agglutination test, although partial common antigenicity was observed in the gel diffusion test with flagellin monomers. These observations suggest that surface antigenic determinants of the lateral flagella of V. alginolyticus and V. harveyi are specific to these two species but internal antigenic determinants buried in the flagellar filaments are partially shared with other vibrio species.

Antigens, Bacterial↗
PubMed1984

Immunohistochemical localization of Na+, K+-ATPase in the choroid plexus.

To determine if canine and rat choroid plexus Na+,K+-ATPase can be localized by immunoperoxidase staining after fixation and embedding, we prepared rabbit antiserum to purified canine kidney medulla Na+,K+-ATPase. When sodium dodecylsulfate polyacrylamide electrophoretic gels of purified canine kidney Na+,K+-ATPase and canine kidney microsomes were treated with antiserum followed by [125I]protein A and autoradiography, the canine microsomes and purified Na+,K+-ATPase showed a prominent radioactive band coincident with the alpha-, beta- and gamma-subunits of the purified canine kidney enzyme. When the rabbit immunoglobulin that was purified from the Na+,K+-ATPase antiserum through DEAE-cellulose ion exchange chromatography was used for immunoperoxidase staining of the choroid plexus fixed with Bouin's fixative, intense immunoreactive staining was present on the epithelial cells of both choroid plexuses but was not found in the tissue around the vessel. The staining was especially confined to apical surfaces of the epithelial cells. The same procedure was performed in the canine kidney, and immunostaining was obtained in the tubules where Baskin and Stahl described the enzyme localization. No staining was seen with pre-immune serum of the normal rabbit. We concluded that both the canine and rat choroid plexus are rich in Na+,K+-ATPase, which plays an important role in cerebrospinal fluid (CSF) secretion.

Animals↗
PubMed1984

Lateral flagellum of Vibrio fluvialis: a species-specific antigen.

Antiserum against lateral flagella (L flagella) of Vibrio fluvialis AQ 0007 was prepared, and H agglutination tests of V. fluvialis strains were carried out with the antiserum. Thirty-seven strains isolated from human patients, marine products, or seawater were tested. All strains, except three which had lost the ability to form L flagella, agglutinated with that antiserum. The antiserum did not agglutinate other vibrio species having L flagella, whereas antisera against L flagella of other vibrios did not agglutinate V. fluvialis. These results suggest that the L flagellar antigen of V. fluvialis is common and specific to the species, and is a useful tool for serological identification of the organism.

Antigens, Bacterial↗