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Biomedical subjects

A Akatsuka

Publications and source records attributed to A Akatsuka.

At least 37 records · Page 2Linked to original sources
PubMed1995

Hepatic cytokeratin changes in obstructive jaundice: before and after biliary drainage.

We investigated the changes in hepatic cytokeratins in obstructive jaundice by immunohistochemistry. The results can be summarized as follows: 1) In accordance with the progression of the jaundice, the lobular and cellular distribution of cytokeratin reactivity in hepatocytes expanded. 2) Cytokeratin reactivity in obstructive jaundice was improved by removal of the bile duct obstruction (decompression), but this decompressive effect deteriorated in the case of prolonged jaundice. 3) It is suggested that the specific lobular and cellular distribution and/or the changes in cytokeratin aggregation might be of value in determining the stage and in predicting the prognosis of obstructive jaundice.

Animals↗
PubMed1994

Appearance of complex branched fibers following repetitive muscle trauma in normal rat skeletal muscle.

BACKGROUND: To examine whether the complex branched fibers observed in mdx mutant mice were formed in normal skeletal muscles, long-term repetitive muscle trauma was applied to muscle of normal Wistar male rats. METHODS: Three kinds of artificial muscle trauma--crush injury, bupivacaine hydrochloride treatment, and forced stretching of contracting muscle (eccentric contraction)--were performed once a week for 10 weeks to achieve a state of repetitive degeneration and regeneration in the muscles. Two weeks after the final treatment, numerical, histochemical, and three-dimensional analyses by scanning electron microscopy were performed. RESULTS: Mean numbers of total branched fibers of the three groups were increased compared with normal control values, especially in the bupivacaine treatment group (three- to fivefold greater than in the other two groups). Aggregations of fibers of the same type which usually appear in mdx mice were observed in various parts of histological sections of the bupivacaine treatment group and only in a part of the crush injury group. No aggregations were observed in sections of the forced stretching group. In the three-dimensional analysis, complex branched fibers appearing as an "anastomosing syncytial reticulum" were observed only in the bupivacaine treatment group. CONCLUSIONS: These findings suggest that the formation of an anastomosing syncytial reticulum is one of the adaptation mechanisms of normal skeletal muscle rather than a specific event in mdx mutant mice, and long-term repeated trauma of the same fiber is necessary for this formation. Adaptive changes in the muscles with the three different types of muscle trauma are discussed.

Animals↗
PubMed1994

Ultrastructural localization of P-glycoprotein on capillary endothelial cells in human gliomas.

The P-glycoprotein (P-Gp) encoded by the human multidrug-resistance gene MDR1 has been suggested to play certain roles in the blood-brain barrier (BBB). However, the detailed mechanism of the activity of P-Gp in multidrug-resistance (MDR) remains unclear in human glioma. We examined the localization of P-Gp in human glioma by immunohistochemical (IHC) and immunoelectron microscopic (IEM) methods with anti P-Gp monoclonal antibodies (C219, MRK16). We also examined MDR1 expression in primary glioma and xenografts by reverse transcription-polymerase chain reaction (RT-PCR) with human MDR1-specific primers. The IHC study showed no P-Gp expression on tumour cells but it was present on capillary endothelial cells and IEM analysis showed definitive localization on their luminal surface. MDR1 gene expression was detected in eight primary glioma and three normal brain specimens by RT-PCR, but not in glioma xenografts. The lack of MDR1 expression in these cells appears to be a consequence of the replacement of the original human stroma, including blood vessels, by murine stroma in glioma xenografts. The unique distribution of P-Gp on the capillary blood vessels was confirmed in human glioma by the results of immunohistochemical and molecular biological studies.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1994

[Epilepsy in patient with structural autosomal abnormality].

Few cases have been reported on the structural autosomal abnormality (SAA) focusing on epilepsy excluding those of Down syndrome and Klinefelter syndrome. We investigated patients who had SAA with special reference to epilepsy. Various types of epilepsy were observed in its severity in our cases as well as previously reported cases. There was no correlation between the degree of mental retardation, motor dysfunction, brain damage on CT scan, and severity of epilepsy. Some cases had brain dysplasia, such as agenesis of corpus callosum, pachygyria, and mega cisterna magna. No correlation was found between these brain dysplasia and severity of epilepsy. It is important for a pediatrician to find a common epileptic syndrome or EEG abnormality in a SAA. An observation of symptoms in patients with the same chromosomal deletion or duplication will lead to identification of responsible gene for an epileptic symptom.

Adolescent↗
PubMed1994

[Clinical consideration of patients with neonatal bilateral basal ganglia-thalamic lesion due to hypoxic ischemic encephalopathy].

We describe herein the clinical symptoms, clinical course and results of investigation of 7 patients with bilateral basal ganglia-thalamic lesions (BBTL). All patients had spastic quadriplegia with rigidity. They were unable to sit and turn over. They could follow objects, turn head towards a sound and recognize parents to some degree. They were all evaluated as having the most severe degree of disability (Oshima's classification 1). They all had dysphagia and 2 patients had a episode of bradycardia and hypothermia, which might be evidences of brain stem disorders. Muscle hypertonia, vomiting, hematemesis and obstructive respiration, which were the major complications for the patients, worsened with age. High percentage of histories of birth asphyxia and poor feeding in the neonatal period suggested that perinatal brain insults might be one of the important factors for developing BBTL. It seemed to be difficult to explain that such diffuse brain injuries in our cases were caused by only the insults during parturition. Brain insults during parturition as well as prenatal factors probably participate in developing BBTL. Although the cerebrum of the patients seem to be relatively preserved in the images of head CT-scan, MRI of the patients revealed diffuse brain lesions. All of five patients tested had an abnormal auditory brain stem response (ABR). These investigations demonstrated that patients with BBTL have diffuse brain damage including brain stem. Further observation is needed to verify the mechanisms of development and the time of onset of BBTL.

Adolescent↗
PubMed1993

Three-dimensional cytoarchitecture of complex branched fibers in soleus muscle from mdx mutant mice.

Three-dimensional cytoarchitecture and types and features of muscle fibers were examined in soleus muscles from mdx mutant mice at different stages of development. In the 2-week-old mice, no abnormal muscle fibers were observed light microscopically, whereas in the 4-week-old animals, disrupted fibers were frequent in light microscopy and scanning electron microscopy. Muscle fibers fused with several short fiber branches appeared at the sixth week after birth and increased in number until the tenth week. In the 1-year-old mice, approximately ten or more muscle fibers were seen fused together. They had many complex branches forming an "anastomosing syncytial reticulum." Muscle fibers with irregular diameters and aggregations of the same type fibers were also observed. Our results demonstrated that these complex branched fibers might be formed by long term repetition of the degeneration and regeneration cycle during the development of soleus muscles, indicating that the characteristic features of muscle fibers with irregular diameters and aggregations of the same type fibers are certainly dependent on the existence of the complex branched fibers.

Animals↗
PubMed1993

Urinary bladder carcinoma producing granulocyte colony stimulating factor (G-CSF): a case report with immunohistochemistry.

A rare case of urinary bladder carcinoma with granulocyte colony stimulating factor (G-CSF) production was reported. In an 83-year-old female, marked neutrophilia in the peripheral blood decreased from 132,500/mm3 to 3,300/mm3 after tumour resection. The tumour was a transitional cell carcinoma. The serum G-CSF level reduced from 238 pg/ml pre-operatively to normal (60 pg/ml) after the operation. Immunohistochemical investigation of the resected tumour with monoclonal antibody specific for G-CSF revealed positive staining in the carcinoma cells, confirming G-CSF secretion.

Aged↗
PubMed1992

Perforin is expressed in CTL populations generated in vivo.

Immunization of C57BL/6 mice with syngeneic tumor cells, MBL-2, resulted in the generation of antitumor effector cells in vivo. The immunized C57BL/6 mice permanently rejected viable MBL-2 lymphoma cells, but not B16 melanoma cells. Cytotoxic T cells obtained from MBL-2-immunized mouse peritoneal cells (PEC) showed specific cytotoxicity against MBL-2, but not to YAC-1, RDM-4 and Meth A cells. By sorting with FACStar, the specific CTL were characterized as TCR alpha beta+ CD8+ T cells. Moreover, the cytoplasm of in vivo-induced CTL was stained with a monoclonal antibody against perforin. The localization of perforin in cytoplasmic granules of CTL was demonstrated by electron microscope analysis. This experiment presented the first evidence that in vivo-induced CD8+ CTL against syngeneic tumor cells expressed significant amounts of perforin.

Animals↗
PubMed1992

Intracellular localization of the HLA class II gene products in transfected mouse L cells.

To investigate the impaired cell surface expression of human major histocompatibility antigen (HLA) in transfected L cells, we examined their intracellular localization by immunocytochemistry. HLA class II molecules produced in transfected L cells were mainly detected in the intracellular vesicles and in the nuclear envelope as granular precipitates. The results suggest that the intracellular transport of the newly synthesized molecules in transfected L cells is impaired at some point along the pathway from the rough endoplasmic reticulum (RER) to the medial-, trans-Golgi apparatus.

Animals↗
PubMed1992

Detection of neuromuscular junctions on isolated branched muscle fibers: application of nitric acid fiber digestion method for scanning electron microscopy.

Three-dimensional morphology and neuromuscular junctions of the branched muscle fibers of the rat skeletal muscles isolated from the rat were examined by application of the nitric acid digestion method for scanning electron microscopy. Treatment with fifteen percent nitric acid and a supersonic wave bath were effective in isolating the branched muscle fibers and for detecting their innervations by scanning electron microscopy. Mean numbers of total and branched fibers in the rat plantaris muscles were 11,130 +/- 314 and 32.4 +/- 4.8 (n = 12), respectively. Bifurcation of these fibers resembled either the letter X (X type) or letter Y (Y type). The Y type fibers were most frequently seen (84% of total branched fibers), and X types accounted for 14%. The remaining 2% of the fibers were subtypes of X and Y with overlapping bifurcation. These branched fibers were differentiated by their length from the bifurcated point, i.e., short, medium and long branches. Neuromuscular junctions on these branched fibers were located almost at the center of their length. The number of innervations was decided by the number of bifurcating fibers across the central part of the length.

Animals↗
PubMed1992

Localization of estrogen receptors and estrogen receptor-mRNA in female mouse thymus.

The present study was performed to demonstrate estrogen receptor (ER) and ER-mRNA in female mouse thymus. The results are as follows: (i) thymic tissue contains ER in both reticuloepithelial(RE)- and T-cell fractions, the ER level being three-fold higher in the former fraction than in the latter; and (ii) thymic tissue contains ER-mRNA at 6.2 kb, a large amount of which was localized in the RE cells and less in the T cells. From these results it is suggested that estrogen (E) mediates some immune function of the mouse thymus through its receptor within RE cells and/or T cells.

Animals↗
PubMed1991

Electron microscopic identification of the intracellular secretion pathway of human G-CSF in a human tumor cell line: a comparative study with a Chinese hamster ovary cell line (IA1-7) transfected with human G-CSF cDNA.

Using monoclonal antibodies specific for human granulocyte colony-stimulating factor (G-CSF), intracellular localization of G-CSF in a G-CSF-producing human tumor cell line (CHU-2) and its ultrastructural characters were described and compared with those of a Chinese hamster ovary cell line (IA1-7) transfected with human G-CSF cDNA. The CHU-2 line, which was derived from a poorly differentiated squamous cell carcinoma of the oral cavity, preserved the character of a poorly differentiated squamous cell carcinoma. In the CHU-2 cell line, there were few cells immunohistochemically positive for G-CSF under light microscopic analysis despite the high transcription level of G-CSF cDNA and secretion of G-CSF that were comparable with cDNA-transfected IA1-7 cells. Using electron microscopy, the reaction products were localized mainly in the perinuclear space (PNS) and rough endoplasmic reticula (RER) without dilation of the cisternae, but they were very rarely found in the Golgi complex and not at all in other intracellular organelles. In contrast, most cells were positive for G-CSF in the IA1-7 cell line. Reaction products in this cell line were also demonstrated in the PNS and RER without dilation of the cisternae. These immunohistochemical findings, in conjunction with the results of Western and Northern blot analysis, suggested that G-CSF was secreted via the PNS and RER without intracellular retention.

Animals↗
PubMed1991

Establishment of epithelial cell lines from human and mouse thymus immortalized by the 12S adenoviral E1a gene product.

To understand the role of thymic epithelial cells in the development of immature thymocytes, the establishment and cloning of thymic epithelial cell lines must be required. In the present study, we established human and mouse thymic epithelial cell lines through the immortalization by the transfection of cDNA sequences of adenoviral E1a 12S mRNA. This procedure resulted in the isolation of five stable cell lines (one human cell line and four mouse cell lines). These cell lines were positive in cytokeratin demonstrated by immunohistochemistry. Electron microscopic study revealed that they had bundles of tonofilaments and desmosome-like tight junctions. These findings indicate that the cell lines immortalized by E1a gene have retained the properties of epithelial cells. MHC class II antigens were not expressed on these cell lines. When interferon-gamma was added to the cultured epithelial cell lines, MHC class II antigens were induced in their cytoplasm and on their surface membrane, demonstrated by immunohistochemical and immunofluorescent studies. It is suggested that these stable cell lines from human and mouse thymus might serve a good tool for the further study of thymocytes differentiation and of unknown cytokines derived from thymus epithelium.

Animals↗
PubMed1991

Localization of sex steroid receptor cells, with special reference to thymulin (FTS)-producing cells in female rat thymus.

Using monoclonal antibodies against progestin receptors (PR) and estrogen receptors (ER), and polyclonal antibodies to thymulin (FTS) and keratin, localization of the sex steroid receptors was studied immunohistochemically in ovariectomized estrogen-treated rat thymus, with special reference to FTS-producing cells. Both ER- and PR-immunostained cells were mainly localized in the medullary region, especially at its periphery (i.e., the corticomedullary junction). A few cells were also situated in the subcapsular area. They were medium- to large-sized and had a dendritic cell process, some of which were immunohistochemically keratin- and FTS-positive, indicative of reticuloepithelial (RE) cells. Hassall's corpuscles were also receptor-positive and FTS-positive. T-cells were not immunostained with anti-ER, anti-PR or anti-FTS. Light microscopically, both ER and PR immunostainings were localized in the cytoplasm and/or nucleus of keratin-stained RE cells. Electron microscopically, both steroid receptors were shown more precisely to distribute as aggregates of osmiophilic black dots on polysomes and perinuclear space in the cytoplasm and on the euchromatin area in the nucleus. These results suggest that the sex steroids E and P exert their effects through receptors within RE cells which produce FTS to regulate T-cell differentiation.

Animals↗
PubMed1990

Thymic stromal cell clone with nursing activity supports the growth and differentiation of murine CD4+8+ thymocytes in vitro.

Thymic stromal cell clone, TNC-R3.1 cell, was established from spontaneous AKR/J mouse thymoma. TNC-R3.1 cell, which has the similar properties to thymic nurse cells, formed a unique complex with normal thymocyte subpopulations. Flow cytometry analysis demonstrated that CD4+8+ and CD4-8- immature thymocytes preferentially interacted with TNC-R3.1 stromal cell clone. CD4+8+ thymocytes, which interacted with TNC-R3.1 stromal cell clone, contained a higher proportion of large size and cycling T cells than did noninteracting CD4+8+ thymocytes. As is generally accepted, CD4+8+ thymocytes did not respond to any stimulation such as IL-2, anti-CD3 mAb (2C11), or IL-2 plus 2C11. However, culture of isolated CD4+8+ thymocytes on TNC-R3.1 stromal cell monolayer in the presence of suboptimal dose of IL-2 induced a significant cell growth. Moreover, the addition of 2C11 and IL-2 into this coculture system resulted in a dramatic increase of the proliferative response of thymocytes. Flow cytometry analysis showed the proliferating cells on TNC-R3.1, which originated from CD4+8+ thymocytes, were mostly TCR-alpha beta+ CD3+CD4-8+ T cells. These results provide in vitro evidence that CD4+8+ thymocytes are at an intermediate stage of T cell maturation and TNC-R3.1 stromal cell clone induces the growth and differentiation of CD4+8+ thymocytes into CD4-8+ T cells.

Animals↗
PubMed1990

Establishment of specific monoclonal antibodies against recombinant human granulocyte colony-stimulating factor (hG-CSF) and their application for immunoperoxidase staining of paraffin-embedded sections.

Detection of granulocyte colony-stimulating factor (G-CSF), one of the substances responsible for proliferation and differentiation of granulocytes, has been performed up to the present by use of the granulocyte colony-formation assay, because of the lack of a specific anti-G-CSF antibody. This has prevented the advancement of biological investigations of cell dynamics linked to G-CSF, e.g., cell localization of G-CSF and its pathophysiological changes. In the present work, two monoclonal antibodies (MAb), 1E7 and 4A6, against recombinant human G-CSF (rhG-CSF) were developed by cell hybridization between NS-1 myeloma cells and splenocytes from a mouse immunized with rhG-CSF. 1E7 and 4A6 were shown to be reactive with hG-CSF but not with other CSF (hGM-CSF, hIL-3, and mouse GM-CSF) by Western blot analysis. An immunoperoxidase staining method using these MAb was then established. This method was applicable to frozen sections, paraffin-embedded sections, and cells fixed with 4% paraformaldehyde. Positive staining for G-CSF was observed in tumor cells secreting G-CSF and also in Chinese hamster ovary (CHO) cells transfected with hG-CSF cDNA. However, no staining was seen in tumor cells secreting no G-CSF, untransfected CHO cells, lung fibroblasts, or bone marrow stromal cells after short periods of culture. These results confirmed the immunospecificity of MAb 1E7 and 4A6 and the validity of their application to immunohistochemistry using paraffin-embedded sections.

Animals↗