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Biomedical subjects

M Tokunaga

Publications and source records attributed to M Tokunaga.

At least 199 records · Page 11Linked to original sources
PubMed1991

Immunoblastic lymphadenopathy (IBL)-like T-cell lymphoma in a child.

We report the case of a 14-year-old Japanese boy with peripheral T-cell malignant lymphoma, showing progression from immunoblastic lymphadenopathy (IBL) to overt malignant lymphoma. He suffered recurrent fever, generalized lymphadenopathy, hepatosplenomegaly and maculopapular exanthema. Leukocytosis with eosinophilia and polyclonal hypergammaglobulinemia were observed during the aggressive course of the disease. In the early phase, human immunoglobulin and steroids improved the symptoms but did not induce complete remission, and the patient died one year after the onset of the illness. Four biopsies of lymph nodes revealed progression from IBL to CD4 positive T-cell lymphoma through IBL-like T-cell lymphoma. Though IBL-like T-cell lymphoma is defined as IBL with neoplastic features and overt T-cell malignant lymphoma progressed from IBL-like T-cell lymphoma is excluded from the definition, it may be preferable that such malignant lymphoma as our case should also be included in IBL-like T-cell lymphoma.

Adolescent↗
PubMed1991

Association of Epstein-Barr virus with undifferentiated gastric carcinomas with intense lymphoid infiltration. Lymphoepithelioma-like carcinoma.

Some undifferentiated gastric carcinomas with intense lymphoid infiltration have a striking resemblance to nasopharyngeal lymphoepithelioma. The authors identified eight such cases (seven patients from Japan and one from the United States) of undifferentiated gastric carcinoma (lymphoepithelioma-like carcinoma [LELC]) and examined them for Epstein-Barr (EBV) viral sequences using polymerase chain reaction (PCR) and in situ hybridization (ISH) techniques. EBV was detected in seven of the eight cases by PCR, including a lymph-node metastasis. ISH that was performed in six of these cases showed EBV genomes to be uniformly present in the carcinoma cells and not present in the reactive lymphoid infiltrate or normal gastric mucosa. PCR of a polymorphic EBV locus (lymphocyte-determined membrane antigen) showed that a single genotype was present in each gastric LELC, consistent with a clonal process. These findings suggest that some undifferentiated gastric carcinomas are EBV-related and that focal EBV infection occurs before transformation.

Antigens, Surface↗
PubMed1991

Cell separation system studied by mixed culture of single wild strain with tetrads-forming mutant strain of Micrococcus luteus.

Mixed culture study of singly occurring wild strain IFO 3333 of Micrococcus luteus and a tetrads-forming mutant strain MT, in the absence or presence of trypsin, supported our previous assumption that at least two kinds of separation systems were involved in cell separation of M. luteus, the one having a physiological role in cutting off the outermost layer of the cell wall (separation system-Om) and the other in cutting off the inner layer of the "proper" cell wall or the septum (separation system-In). The separation system-Om of IFO 3333 insensitive to trypsin substituted, freely from the cells, for that of MT sensitive to trypsin.

Micrococcus luteus↗
PubMed1990

Secretion of killer toxin encoded on the linear DNA plasmid pGKL1 from Saccharomyces cerevisiae.

By the kar1-mediated cytoduction, linear double-stranded DNA plasmids pGKL1 and pGKL2, encoding killer toxin complex, have been successfully transferred to the recipient strains with about 30% frequency. The killer toxin was found to be secreted through the normal yeast secretory pathway by introducing pGKL plasmids into the several Saccharomyces cerevisiae sec mutants and examining the secretion of killer toxin. S. cerevisiae cells, harboring newly isolated deletion plasmid pGKL1D, expressed only the 28K protein among three killer subunits, and secreted the 28K subunit at a level of zero to 20% efficiency of the cells containing intact pGKL1 plasmid. These data indicated that subunit interaction (cosecretion) of killer proteins is required for the efficient secretion of 28K subunit. The 28K precursor protein was found to translocate across the canine pancreatic endoplasmic reticulum membrane under the direction of its own signal peptide in vitro without any other subunits. From kex2 mutant cells harboring pGKL1 plasmid, the 97K subunit, and its precursor 128K protein were not secreted, however, the 28K subunit was secreted in the same amount as that secreted from KEX2 cells. These lines of evidence suggest that the final assembly of killer toxin complex after KEX2 site of Golgi apparatus is not essential for the secretion of 28K subunit, and therefore, that putative interaction between 128K protein and 28K subunit for the transport between endoplasmic reticulum and Golgi apparatus may be required for the efficient secretion of 28K subunit.

Animals↗
PubMed1990

Initial attachment of Candida albicans cells to buccal epithelial cells. Demonstration of ultrastructure with the rapid-freezing technique.

The rapid-freezing technique was applied in association with scanning and transmission electron microscopy to observe the initial attachment (or contact) of Candida albicans cells to exfoliated human buccal epithelial cells. Low temperature scanning electron microscopy provided detailed three-dimensional morphological features of the yeast-epithelial cell association; adhesion of C. albicans cells to host cells was primarily owing to an interaction between fibrillar layer of the yeast cell wall and the membrane interdigitations of the epithelial cells. Such a particular interconnection between the two cells was confirmed by the freeze-substitution fixation for transmission electron microscopy. These results clearly demonstrate the outermost fibrillar cell wall layer of C. albicans responsible for adhesion to host cells.

Candida albicans↗
PubMed1990

Cell surface of a tetrads-forming mutant of Micrococcus luteus: chemical treatment of the cells and teichuronic acids on the surface.

Tetrads-forming mutant MT cells of Micrococcus luteus, both treated with chemical reagents and non-treated, were observed with a scanning electron microscope (SEM). The agglutinability of the cells with antiserum containing anti-teichuronic acid antibody was examined. The binding of protein A-gold particles to the cells, mediated with the antiserum, was also observed with SEM. A tetrad surface, not surface of each of four "unit monococci" constituting a tetrad, consisted of two or three smooth areas with borders. The difference in the surface features between M. luteus wild-type IFO 3333 (Monodane et al, Microbiol. Immunol. 33: 165-174, 1989) and the mutant MT cells is discussed.

Cell Wall↗
PubMed1990

Comparison of two kinds of cell packets of Micrococcus luteus by scanning electron microscopy: outermost layer maintaining the packet structure.

Two kinds of cell packets of Micrococcus luteus, one having teichuronic acids (TUA) in the cell wall and the other lacking TUA, have been independently reported by two groups of workers. A comparison by scanning electron microscopy of these packets provided a possibly consistent interpretation for the seemingly conflicting opinions whether TUA were involved in packet induction. It was strongly suggested that the packets having TUA in the wall were rigidly maintained by a bridging structure of the outermost layer of the peripheral wall, while the packets lacking TUA showed low contribution of the outermost layer to the bridging structure probably due to the absence of TUA.

Cell Wall↗
PubMed1990

Biclonality of composite B- and T-cell lymphomas. A case report.

Most composite lymphomas which are composed morphologically of two different tumor cell types are considered to represent different morphological expressions of a single clone. However, in recent years, composite B- and T-cell lymphomas and biclonality of B-cell lymphoma have been reported. We experienced a case of composite lymphoma which initially developed as cutaneous lymphoma composed of lymphoplasmacytes associated with large clear cells. It was confirmed that the tumor cells of these two systems were biclonal on the basis of surface markers and DNA rearrangements, i.e. B cells of the IgG kappa type, showing IgH and kappa chain DNA rearrangement, and T-cells with CD4 surface marker, showing rearrangement of the T-cell receptor beta chain gene. This case showed a predominant B-cell pattern at the initial stage, and terminated in T-cell lymphoma, as revealed at autopsy. Therefore we considered this case to be a unique composite lymphoma showing biclonality of both B- and T-cell systems, providing a number of suggestions for future study of malignant lymphoma.

Aged↗
PubMed1990

Ectopic nesidioblastosis.

We observed one case of ectopic nesidioblastosis. A solitary nesidioblastoma was observed in the anterior wall of the duodenum. Ectopic nesidioblastosis has not been previously reported, but our experience suggests the necessity of examination for ectopic pancreas in cases of SIDS or its near-miss.

Blood Glucose↗
PubMed1990

Influence of surrounding media on preservation of cell wall ultrastructure of Candida albicans revealed by low temperature scanning electron microscopy.

Influence of surrounding media on the surface structures of the cell wall of Candida albicans was discussed with respect to the preservation of ultrastructure during the specimen preparation for scanning electron microscopy. The fibrillar structure of the cell surface was distinctly identified by the rapid-freezing technique. It was difficult, however, to observe this structure by the conventional specimen preparation technique. The reason for the difference between these two preparation techniques was studied using a low temperature SEM. Through investigating the influence of each step of the conventional technique on the fibrillar structure, it was found that the fibrils were drastically deformed and disappeared during the dehydration step in ethanol above 80% in concentration. In order to study which physicochemical properties participated in this disappearance phenomenon, yeast cells were treated with various media: solutions in different pH ranges and at different salt concentrations, ionic solutions, surfactants, formamide, dimethyl sulfoxide, acetone and Fehling's solution. As a result, the fibrillar structure was found well preserved when the medium had an affinity for the constituent molecules of the fibrils. When without affinity, the fibrils suffered a remarkable deformation. The mechanism of this deformation is discussed in terms of molecular interaction of solute and solvent.

Candida albicans↗
PubMed1990

Retrovirus-like particles in human thymomas.

The pathogenesis of thymoma is unclear. In this study retrovirus-like particles in human thymomas were detected by electron microscopy. Forty-two thymomas; 25 without complications and 17 associated with autoimmune disorders such as myasthenia gravis (13), systemic lupus erythematosus (1), polymyositis (1), Sjögren's syndrome (1), and pure red cell anemia (1), were examined. Thymic tissues from 9 infants suffering from congenital heart diseases and 7 hyperplastic thymuses obtained from myasthenic patients served as controls. The retrovirus-like particles were observed in 37.0% of thymomas without complications; 50.0% of thymomas associated with myasthenia gravis and other autoimmune disorders; 62.5% of thymuses associated with myasthenia gravis; and 33.3% of thymuses from infants with heart disease. The envelopes, including the central cores of the retrovirus-like particles, had diameters ranging from 70 to 460 nm, depending on the source of the specimen. The retrovirus-like particles were located in the cytoplasm, vacuoles, vesicles and lumens of the endoplasmic reticula of epithelial and/or plasma cells. Some retrovirus-like particles were seen budding from plasma membranes. These observations suggest that the retrovirus-like particles in thymomas might be an activated form of retrovirus originating in normal thymic tissue.

Heart Defects, Congenital↗
PubMed1990

[Oculopharyngeal muscular dystrophy in a Japanese family].

The first instance of familial oculopharyngeal muscular dystrophy (OPMD) affecting a Japanese family is reported. Three patients (a 62-year-old female, her sisters 66-year-old and 53-year-old) were described with suspicious other 2 cases. A 62-year-old woman (case 1) developed bilateral blepharoptosis at the age of 52. Then she became aware of difficulty in swallowing solid foods, had developed a nasal voice and aspiration of liquids. On admission, neurological examination revealed moderate bilateral blepharoptosis, nasal voice, dysphagia and hyporeflexia of the pharynx. There was mild weakness of the muscles of the temporalis, masseter, face, neck and proximal portions of the upper limbs. The levels of serum creatine phosphokinase, lactic acid and pyruvic acid were normal. Tensilon test was negative. The needle EMG showed a myogenic pattern with no waning phenomenon. Nasopharyngeal fiberscopy, laryngoscopy, esophageal fluoroscopy and hydrodynamic examination showed dyskinesis of the soft palate, retention of saliva in recessus piriformis and streaming into the larynx. Cricopharyngeal myotomy was performed for the purpose of relieving the dysphagia. The muscles were obtained from cricopharyngeus of both sides during surgery, and right deltoid muscle in biopsy. The muscles of sternohyoideus and deltoideus showed myogenic changes, and some fibers with rimmed vacuoles especially in small angulated fibers under the light microscope. Whereas the crycopharyngeus showed dystrophic change, which was apparent in the right side. There were also nemaline rods found in a few fibers undergoing necrosis. ATPase preparations revealed type 1 predominant in cricopharyngeus and type 2 predominant in sternohyoideus. Most atrophic fibers were in type 1 fibers.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1990

Pathoepidemiological features of adult T-cell lymphoma/leukemia in an endemic area: Kagoshima, Japan.

In order to elucidate the pathological and epidemiological features of malignant lymphoma (ML), particularly of adult T-cell lymphoma/leukemia (ATLL) in the Kagoshima district, age-adjusted and age-specific incidence rates of malignant lymphomas were estimated on 3239 histologically confirmed cases between the years 1963 and 1987. There was a marked increase in the incidence rate from 1976 (4.9) to 1982 (8.5) due to the increase of T-cell lymphomas. The increase was not conspicuous after 1982. Immunohistochemically, all of the 429 MLs found in 1985 and 1986 were examined on paraffin sections and 70 ATLL cases on fresh frozen sections. T-cell ML comprised 65.3%, B-cell ML 30.5%, Hodgkin disease 2.6%, and histiocytic ML 1.2%. Most of ATLL cells were phenotypically CD4+ CD8-, 14% of ATLL cases showed CD4+ CD8+, 6% were CD4- CD8+, and 7% were CD4- CD8-. The simulataneous expression of IL 2 and IL 2R was seen in 8 (16%) out of 56 patients examined. Therefore, a proliferation by autocrine mechanism does not seem to be a major course of ATLL progression.

Age Factors↗
PubMed1990

Chemical treatments of the cell packets induced from a Micrococcus luteus mutant and teichuronic acids on the packet surface.

Cell packets (MT packets) induced from a tetrads-forming mutant (strain MT) of Micrococcus luteus, both treated with chemical reagents and non-treated, were observed with a scanning electron microscope (SEM). The agglutinability of MT packets with antiserum containing anti-teichuronic acid antibody was examined. The binding of protein A-gold particles to the MT packets, mediated with the antiserum, was also observed with SEM. Gold particles were observed uniformly on the whole packet surface and also on the bridging structure formed by the outermost layer of the cell wall. Mild acid treatment, NaIO4-NaBH4 treatment and mild Smith degradation of the MT packets extremely decreased the agglutinability and binding of protein A-gold particles. The treatments gave a little influence on the surface feature and appreciably destroyed the regular packet structure. It was supposed that teichuronic acids distributed uniformly on the whole packet surface, naturally on the surface of the bridging structure too, and appreciably participated in the maintenance of the regular packet structure.

Cell Membrane↗
PubMed1989

Synthesis and secretion of human nerve growth factor by Saccharomyces cerevisiae.

The DNA coding for human nerve growth factor (hNGF) was chemically synthesized and introduced into Saccharomyces cerevisiae. Expression and secretion of hNGF was obtained by use of the yeast phosphoglycerate kinase-encoding gene promoter and the pre-pro sequence of the yeast alpha-mating factor. Immunoblotting with antiserum raised against a protein A-hNGF fusion protein, allowed the detection of an immunoreactive material secreted into the culture medium. A preparation from the culture medium, partially purified by ion-exchange column chromatography, stimulated neurite outgrowth from rat pheochromocytoma PC12h cells.

Amino Acid Sequence↗
PubMed1989

Expression of pGKL killer 28K subunit in Saccharomyces cerevisiae: identification of 28K subunit as a killer protein.

Saccharomyces cerevisiae and other yeast cells harboring the linear double stranded (ds) DNA plasmids pGKL1 and pGKL2 secrete a killer toxin consisting of 97K, 31K and 28K subunits into the culture medium (EMBO J. 5, 1995-2002 (1986), Nucleic Acids Res., 15, 1031-1046 (1987]. The 28K subunit of the killer toxin was successfully expressed in S. cerevisiae when it was cloned on a circular plasmid with its putative promoter region replaced with that of S. cerevisiae chromosomal genes. The expression of the 28K subunit of the killer toxin in killer-sensitive cells resulted in the death of the host cells. This killing activity by the 28K subunit was prevented by the expression of the killer immunity, indicating that the killing activity of the killer toxin complex was carried out by the 28K subunit. Although the 28K subunit was synthesized as a intact precursor protein with its own signal sequence, it was not secreted into the culture medium but remained in the host cells. This indicated that 28K subunit killed host cells from inside of the cells rather than from outside. We further suggested that 28K killer subunit without 97K and 31K subunits did not kill the killer-sensitive cells from outside.

Fungal Proteins↗
PubMed1989

Electron microscopic mappings of myosin head with site-directed antibodies.

Site-directed antibodies were raised against three synthetic peptides whose sequences correspond to a region around the reactive lysine residue and two protease-sensitive regions of subfragment 1 (S1) of skeletal muscle myosin (one at the junction of the 23,000 Mr and 50,000 Mr segments, the J1 junction; and the other at the junction of the 50,000 Mr and 20,000 Mr segments of the heavy chain, the J2 junction). The antisera cross-reacted with intact myosin with titres of 5 x 10(4) (anti-J1 antiserum) and 10(4) (anti-J2 and anti-reactive lysine residue antisera). Site-specific antibodies purified by S1-Sepharose readily bound to myosin. Electron microscopic examinations of antibody-myosin complexes revealed that the J1 and J2 junctions are located 15 nm and 16 nm from the head-rod junction, respectively, while the reactive lysine residue region is 13 nm from the junction.

Animals↗