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Biomedical subjects

T Akagi

Publications and source records attributed to T Akagi.

At least 289 records · Page 16Linked to original sources
PubMed1988

Isolation of virus-producing transformants from human gastric cancer cell line, HGC-27, infected with human T-cell leukemia virus type I.

A human anaplastic gastric cancer cell line, HGC-27, showed marked degeneration with formation of multinucleated syncytia and cell detachment of nearly all cells which began 24 hr after and reached a maximum 2 to 3 days after co-cultivation with X-irradiated MT-2 cells, HTLV-I producing human cord leukocytes. Less severe degeneration without formation of syncytia was also observed in the cultures inoculated with cell-free MT-2 culture media. Morphologically altered cells began to proliferate and formed piled up colonies in some of the cultures co-cultivated with X-irradiated MT-2 cells after a long culture period. The two clones designated HGC/MT2 (Cl-1) and HGC/MT2 (Cl-2) were separated by cell cloning. HGC/MT2 (Cl-1) and HGC/MT2 (Cl-2) cells were positive for HTLV-I gag proteins (p19 and p24) and pX gene products, p40x, as demonstrated by immunohistochemistry and immunoblotting analysis, contained HTLV-I provirus DNA, and consistently produced type C virus particles.

Cell Transformation, Viral↗
PubMed1988

Identification of a cis-regulatory element involved in accumulation of human T-cell leukemia virus type II genomic mRNA.

The X gene products of the human T-cell leukemia viruses type I and II are thought to be involved not only in viral replication but also in mediating the expression of certain cellular genes. These X gene products are known to be translated from doubly spliced viral mRNA, while viral structural proteins, such as the gag, pol, and env gene products, are translated from unspliced or singly spliced viral mRNA. One of the X gene products of human T-cell leukemia virus type II, tax2 protein, has been shown to be responsible for transcriptional stimulation from the viral long terminal repeat. The other X gene product(s) of human T-cell leukemia virus type II, the rex2 protein(s), is located in the nuclear fraction of virus-infected cells, but its function is not known. This article reports evidence that rex2 protein(s) enhances the accumulation of unspliced viral RNA by interacting posttranscriptionally, either directly or indirectly, with a cis-regulatory element downstream from the first splice donor site in the long terminal repeat.

Cell Line↗
PubMed1988

Evidence for phosphorylation of trans-activator p40x of human T-cell leukemia virus type I produced in insect cells with a baculovirus expression vector.

Human T-cell leukemia virus type I (HTLV-I) encodes a trans-activator protein p40x which positively regulates transcription of the viral RNA as well as interleukin-2 and its receptor genes. We placed a cDNA coding for p40x in baculovirus Bombyx mori nuclear polyhedrosis virus (BmNPV) expression vectors. Infection of BmN cells derived from an insect, B. mori (silkworm), with a recombinant virus led to the production of soluble p40x. The biological activity of the recombinant p40x was demonstrated by introducing the protein into intact NIH 3T3 cells that had been selected for genomic integration of HTLV-I LTR connected with the CAT gene. Immunocytochemical and cell fractionation analyses showed the localization of p40x in both the cytoplasmic and nuclear fractions of BmN cells. Analyses of 32P-labeled proteins of BmN cells by cell fractionation and subsequent immunoprecipitation revealed that the p40x present in each subcellular fraction was phosphorylated. The post-translational modification was inhibited by the addition of a protein kinase inhibitor K252a during the metabolic labeling of BmN cells. Phosphoamino acid analysis indicated that the phosphorylation occurred on serine residues of p40x.

Animals↗
PubMed1988

[Balloon valvuloplasty for pulmonary valvular stenosis: a long-term follow-up study using pulsed Doppler echocardiography].

From June 1984 to March 1987, percutaneous balloon valvuloplasty (PBV) was performed for 22 patients with congenital pulmonary valvular stenosis. It was successful for 20 patients, and there were significant decreases of transvalvular pressure gradients; 72 +/- 30 mmHg before PBV, and 30 +/- 12 mmHg immediately after PBV (p less than 0.001). In a follow-up study, pulsed Doppler echocardiography and cardiac catheterization were used to examine changes in long-term hemodynamic findings after PBV. One year follow-up evaluation was performed for 14 patients, and two year follow-ups for seven patients. One year after PBV the transvalvular pressure gradients were evaluated during cardiac catheterization in 11 patients, and using pulsed Doppler echocardiography in the remaining three patients. The gradients of the seven patients at two year intervals after PBV were evaluated using pulsed Doppler echocardiography. The pressure gradients of two patients improved further one year later due to the anatomical degradation in the right ventricular outflow tracts. For seven patients, two year follow-up evaluations were performed, and the transvalvular pressure gradient reduced from 84 +/- 23 to 33 +/- 15 mmHg (p less than 0.001) immediately afterwards; to 27 +/- 22 mmHg (p less than 0.01) one year later; and further to 12 +/- 5 mmHg (p less than 0.001) two years after PBV. Second PBV was performed for three patients in whom a residual gradient was recognized, with the good results. On auscultation, a pulmonary regurgitant murmur was recognized in 28% of 18 patients immediately after PBV, but 80% of this resolved one year later. Two patients had pulmonary regurgitation with pulmonary valvular stenosis before PBV.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1987

Electron microscopic study of mucoepidermoid carcinoma in the pancreas.

An autopsy case of extremely rare mucoepidermoid carcinoma of the pancreas in a 58-year-old male was reported. The main tumor in the pancreatic tail associated with wide-spreading metastases, was histologically composed of squamous cancer cell nests intermingled with mucin-containing cells, but not true glandular structures except for metastatic foci in the liver. Electron microscopic findings of the main tumor revealed roughly three kinds of cancer cells, namely undifferentiated cells, squamous cells, and squamous cells with mucin-containing intracytoplasmic lumina, accompanied by variety of transitional forms. The mucin was similar to that of the intra-or interlobular duct epithelium of pancreas in mucin stains. Immunohistochemically, positive immune reaction of the cancer cells was observed by anti-keratin, -epithelial membrane antigen and -carcinoembryonic antigen sera. These findings suggested that the cancer cells originated from undifferentiated cells of pancreatic duct, which showed multipotency to differentiate predominantly into squamous cells, but also into mucin-producing cells.

Carcinoma↗
PubMed1987

Multiple carcinoid tumor combined with mucosal carcinoma in the stomach. A case report.

A case of gastric multiple carcinoid tumor combined with mucosal carcinoma in a 63-year-old female is reported. The carcinoid tumors, larger than 0.5 mm in diameter, and endocrine cell micronests, smaller than 0.5 mm in diameter, were mostly located in areas of chronic atrophic gastritis. Their distribution was coincident with that of multiple carcinoid tumor in type A gastritis. The majority of the tumor cells were positive for human chorionic gonadotropin (HCG) and Leu 7 by immunohistochemistry and contained various numbers of intracytoplasmic secretory granules as revealed by electron microscopy. Two mucosal carcinoma foci did not show endocrine characteristics. These carcinoid tumors were thought to have originated in HCG-producing argyrophil cells which had been stimulated by hypergastrinemia accompanying chronic atrophic gastritis. The mucosal carcinomas were regarded as incidental.

Carcinoid Tumor↗
PubMed1987

Ultrastructural and immunological studies of virus particles observed in a T-cell line derived from a mouse spontaneous lymphoma.

Intracytoplasmic type A virus particles in clusters, associated with budding, immature type B and mature type B-like particles were observed in a T-cell line derived from a spontaneous lymphoma of an A/J mouse. These particles shared the antigenic determinants with murine mammary tumor virus from RIII, C3H, and GR strains as revealed by both indirect immunofluorescence and immunoperoxidase methods at ultrastructural level.

Animals↗
PubMed1987

An immunohistochemical study on the distribution of glial fibrillary acidic protein, S-100 protein, neuron-specific enolase, and neurofilament in medulloblastomas.

In order to clarify the differentiation of medulloblastomas, the authors studied on the morphological features and immunohistochemical expression of glial fibrillary acidic protein (GFAP), S-100 protein, neuron-specific enolase (NSE), and neurofilament (NF) in 31 medulloblastomas. GFAP was detected only in a small number of tumor cells of 5 medulloblastomas; S-100 protein in both small tumor cells and some so-called spongioblastic cells in 16 medulloblastomas; NSE in the more abundant tumor cells and the matrix in 28 medulloblastomas; NF in a few tumor cells of 12 medulloblastomas; GFAP and NF in 2 medulloblastomas, but each of them in different tumor cells. These results suggest that medulloblastomas have a capacity of differentiation along neuronal and/or glial lines. The conventional morphological markers of differentiation in medulloblastomas such as spongioblastic cells and Homer Wright rosettes were not necessarily compatible with expression of immunohistochemical markers such as GFAP or NF. NSE and S-100 protein seem less valuable markers of differentiation because they were detected in both neuronal and glial elements. But NSE, which was observed in most medulloblastomas, might have a value as a marker for medulloblastomas.

Adolescent↗
PubMed1987

Craniopharyngioma in the third ventricle: necropsy findings and histogenesis.

A case of craniopharyngioma confined within the third ventricle with necropsy is reported. A stalk-like structure in this tumour was present in the wall of the third ventricle at its base. It is suggested that this tumour might have arisen from the remnants of Rathke's pouch persisting in the tuber cinereum.

Cerebral Ventricle Neoplasms↗
PubMed1987

Metaplastic bone formation in a hyperplastic polyp of the stomach: a case report.

Metaplastic bony tissue along with hyperplastic mucosal epithelium showing no atypism was detected in biopsy materials from a Yamada type I gastric polyp. The tissue was metaplastic woven bone associated with calcification. Histogenesis of the bone formation is as yet unknown. This is the first reported case of the presence of metaplastic bone accompanied by hyperplastic gastric mucosa so far.

Aged↗