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Biomedical subjects

M Tokunaga

Publications and source records attributed to M Tokunaga.

At least 181 records · Page 10Linked to original sources
PubMed1993

[A clinical study on respiratory management using a respirator with nasal intubation in patients undergoing surgery for esophageal cancer].

We analyzed a postoperative respiratory management using a respirator with nasal intubation in 55 patients who underwent subtotal esophagectomy through thoracic and abdominal approach between April 1984 and December 1989. In 21 cases (38%) the period using a respirator was within 3 days, in 24 cases (44%) during 4-7 days, and in 10 cases (18%) over 8 days. Postoperative pulmonary complications occurred in 20 cases (36%); pneumonia in 7 cases (13%), lung edema in 12 cases (22%), atelectasis in one case (2%). Two patient died after surgery, one from acute myocardial infarction, another from multiple organ failure after anastomotic leakage. The period using a respirator was positively correlated with the operative blood loss, transfusion and post-operative infusion, postoperative pulmonary complications positively correlated with the operative time, the anesthetic time, operative blood loss, transfusion and postoperative infusion as well as with preoperative complications and renal dysfunction too. In 120 cases before 1984, postoperative pneumonia occurred in 42 cases (36) and 19 cases (16%) of them died. These results suggest that our respiratory management using a respirator is effective in perioperative period of esophageal cancer.

Aged↗
PubMed1993

Epstein-Barr virus in gastric carcinoma.

Epstein-Barr virus (EBV) is known to be related to lymphoid tumors and some types of epithelial tumors, including lymphoepithelioma-like gastric carcinoma with marked lymphocytic stroma. In this study, prevalence of EBV involvement in gastric cancer, and characteristics of tumors with such involvement, were investigated by EBV-encoded RNA 1 in situ hybridization applied to paraffin sections, including the tumor and adjacent gastric tissue, from 999 gastric carcinomas observed in 970 consecutive cases from a large Japanese hospital. EBV involvement occurred in 6.9 percent of lesions, a significantly lower proportion than has been observed in a North American series. Involvement was significantly more frequent among males, in tumors in the upper part of the stomach, and in adenocarcinomas of the moderately differentiated tubular and poorly differentiated solid or medullary types. Almost all carcinomas with marked lymphoid stroma were EBV-positive. Positive lesions were characterized by the presence of uniform hybridized signals in almost all carcinoma cells and by their absence from adjacent non-neoplastic tissue.

Adult↗
PubMed1993

Epstein-Barr virus in adult T-cell leukemia/lymphoma.

Adult T-cell leukemia/lymphoma (ATLL) is a well-known human T-cell lymphotropic virus type-1-related disease. We studied Epstein-Barr virus (EBV) in the tumor cells of ATLL, to investigate the etiological significance of double infection with these viruses. We used polymerase chain reaction and EBV-encoded small RNA-1 in situ hybridization to investigate the presence of EBV and immunohistochemistry to detect EBV-related oncoproteins, such as EBV-determined nuclear antigen-2 and latent membrane protein. Polymerase chain reaction performed on DNA of frozen specimens from 96 cases of ATLL revealed that the tumor tissue from 21 cases contained EBV DNA. EBV-encoded small RNA-1 in situ hybridization performed on the paraffin sections of the polymerase chain reaction-positive cases indicated EBV in the nuclei of ATLL tumor cells in 16 cases, nine of which were in the pleomorphic nuclei. Latent membrane protein was also detected in the cytoplasm of ATLL tumor cells in 15 cases, and EBV nuclear antigen-2 was observed in the nuclei of ATLL tumor cells in 11 cases. We conclude that EBV was present within tumor cells in about 17% of cases with ATLL and expressed EBV oncoprotein in the tumor cells. It is hypothesized that EBV and human T-cell lymphotropic virus-1 may infect the same T cells in early life and may play a role in the oncogenesis of ATLL.

Antigens, CD↗
PubMed1993

Pulmonary involvement in human T-cell lymphotropic virus type-I uveitis: T-lymphocytosis and high proviral DNA load in bronchoalveolar lavage fluid.

The ocular manifestation of human T-cell lymphotropic virus type I (HTLV-I) infection has been recognized as a new clinical entity termed HTLV-I uveitis. In order to determine whether HTLV-I uveitis is associated with lymphocyte alveolitis, bronchoalveolar lavage (BAL) was carried out in 11 patients with HTLV-I uveitis, five asymptomatic HTLV-I carriers, 11 HTLV-I-negative patients with ocular sarcoidosis, and nine normal control subjects seronegative for HTLV-I. Six of the 11 patients with HTLV-I uveitis showed increased total cell counts, and T-lymphocytosis in BAL fluid. CD4+/CD8+ ratios of T-lymphocytes were decreased in three of these patients, and normal in three other patients. Such abnormalities of the lung were not found in asymptomatic HTLV-I carriers, and in normal control subjects. BAL findings in HTLV-I uveitis differed from those of patients with sarcoidosis in terms of the lymphocytic component. Interestingly, it was found that there was an increase of HTLV-I proviral deoxyribonucleic acid (DNA) load in peripheral blood mononuclear cells (PBMC) from seven patients with HTLV-I uveitis, and in the BAL cells from four patients with pulmonary involvement. These results provide further evidence in terms of HTLV-I tropism for the lung, and suggest that a systemic and local increase of HTLV-I proviral DNA load plays an important role in the pathogenesis of lymphocyte alveolitis in patients with HTLV-I uveitis.

Bronchoalveolar Lavage Fluid↗
PubMed1993

[A case report of an advanced esophageal carcinoma treated by neoadjuvant chemotherapy (CDDP + 5-FU) and evaluation of effect on metastatic lymph nodes].

A 69-year-old woman was diagnosed to have type 2 advanced esophageal carcinoma measuring Im 9 cm by X-ray and endoscopic examination. CT scan revealed much swelling of No. 106 and 9 lymph nodes. As the patient had dry cough and these lymph nodes, we tried neoadjuvant chemotherapy for reduction of metastatic lymph nodes. The regimen consisted of CDDP 80 mg/m2 (day 1), 5-FU 800 mg/m2 (day 1-4, continuous). After 2 courses, an operation was performed. Histopathological examination of the section of the primary tumor revealed that only a few cancer cells nests (sq. c.c., mod.) remained in the muscle layer. In 41 dissected lymph nodes, 12 lymph nodes had metastatic cancer cell nests before neoadjuvant chemotherapy and only 4 lymph nodes had a few remaining cancer cells nests. The effect of CDDP + 5-FU therapy is the same for primary tumor and lymph nodes.

Aged↗
PubMed1992

Small-angle synchrotron x-ray scattering reveals distinct shape changes of the myosin head during hydrolysis of ATP.

In the energy transduction of muscle contraction, it is important to know the nature and extent of conformational changes of the head portion of the myosin molecules. In the presence of magnesium adenosine triphosphate (MgATP), fairly large conformational changes of the myosin head [subfragment-1 (S1)] in solution were observed by small-angle x-ray scattering with the use of synchrotron radiation as an intense and stable x-ray source. The presence of MgATP reduced the radius of gyration of the molecule by about 3 angstrom units and the maximum chord length by about 10 angstroms, showing that the shape of S1 becomes more compact or round during hydrolysis of MgATP. Comparison with various nucleotide-bound S1 complexes that correspond to the known intermediate states during ATP hydrolysis indicates that the shape of S1 in a key intermediate state, S1-bound adenosine diphosphate (ADP) and phosphate [S1**.ADP.P(i)], differs significantly from the shape in the other intermediate states of the S1 adenosine triphosphatase cycle as well as that of nucleotide-free S1.

Adenosine Triphosphate↗
PubMed1992

Purification and characterization of BiP/Kar2 protein from Saccharomyces cerevisiae.

Using specific anti-BiP/Kar2 antibody as the probe, we have developed an efficient purification method of BiP/Kar2 protein from the total cell extract of Saccharomyces cerevisiae. Overproduction of BiP/Kar2 protein was achieved by the cloning of the KAR2 gene on multicopy plasmids and the treatment of cells harboring the cloned KAR2 gene with tunicamycin. Freeze-thaw treatment, hydroxyapatite high pressure liquid chromatography, and ATP-agarose column chromatography of crude extract yielded homogeneous BiP/Kar2 protein (including less than 0.2% of degradative derivative) with a 430-fold purification and 28% recovery. Edman degradation of purified BiP/Kar2 suggests that the mature protein corresponds to a processed product with the removal of a 42-amino acid presequence. It is active as a homodimer and exhibits ATPase activity with a specific activity of 2 pmol/min/micrograms of protein. Protease susceptibility indicated that the ADP form of BiP/Kar2 is more resistant than the ATP form to the chymotrypsin digestion and that BiP/Kar2 required the presence of ATP to avoid the irreversible denaturation. Synthesis of BiP/Kar2 was induced by the inducible expression of an aberrant heterologous protein, yeast killer prepro-signal mouse alpha-amylase fusion protein.

Adenosine Triphosphatases↗
PubMed1992

Structure of yeast pGKL 128-kDa killer-toxin secretion signal sequence. Processing of the 128-kDa killer-toxin-secretion-signal-alpha-amylase fusion protein.

The linear double-stranded DNA plasmid pGKL1 in yeast encodes a killer toxin consisting of 97-kDa, 31-kDa and 28-kDa subunits. A 128-kDa protein precursor of the 97-kDa and 31-kDa subunits, was first synthesized with a 29-amino-acid extension at its NH2-terminus as a secretion signal sequence. In the present study, the property of this signal sequence was studied by the analysis of a fusion protein with mouse alpha-amylase. Using the secretion signal sequence of the killer protein, the mouse alpha-amylase was successfully secreted into the culture medium. An intracellular precursor form of alpha-amylase was identified and purified. Analysis of the NH2-terminal sequence of this precursor molecule indicated that it corresponded to the secretory intermediate (pro form) of alpha-amylase with the removal of the hydrophobic segment (Met1-Gly16) of the secretion signal. Both the secretion of alpha-amylase into the culture medium and the detection of the pro-alpha-amylase species in the cells were prohibited by a sec 11 mutation, or by the conversion of Gly to Val at the 16th position of the secretion signal. These results strongly suggest that the cleavage occurs between Gly16 and Leu17 by a signal peptidase, and that this cleavage is required for the secretion of alpha-amylase into the medium. Based on the data from the NH2-terminal amino acid sequences of secreted alpha-amylases, we conclude that the 29-amino-acid secretion signal present in the 128-kDa killer toxin precursor protein is a prepro structure.

Amino Acid Sequence↗
PubMed1992

Immunohistological quantitative analysis of S100 protein-positive cells in T-cell malignant lymphomas, especially in adult T-cell leukemia/lymphomas.

S100 protein-positive cells (S100+ cells) in 36 cases of T-cell lymphoma (T-ML) in the lymph node and 15 cases of T-ML in the skin were analyzed immunohistologically in order to study their quantitative features in adult T-cell leukemia/lymphoma (ATLL). The T-MLs were categorized according to the updated Kiel classification, and the T-cell pleomorphic type (Pleo) was subcategorized into 3 subtypes: Pleo-ATLL, Pleo-clear and Pleo-others. The population of S100+ cells and the first to fifth minimal distances of every S100+ cell were measured on micrographs of paraffin sections that had reacted to anti-S100 protein antibody according to the ABC method. Lymphoblastic and chronic lymphocytic leukemia types showed low populations of S100+ cells and long values of the first minimal distance. T-zone lymphoma without follicles and angioimmunoblastic lymphadenopathy with dysproteinemia-type T-ML had high populations and low values of the first minimal distance. Among the three subtypes of Pleo in the lymph node, Pleo-ATLL gave the highest population and the shortest value of the first minimal distance of S100+ cells, but this trend was not found in the skin. Clusters of more than five S100+ cells were more common in the Pleo-ATLL subtype than in the other two subtypes. The increase and clustering of S100+ cells in Pleo-ATLL suggests that the lymphoma cells act on S100+ cells as a helper.(ABSTRACT TRUNCATED AT 250 WORDS)

Diagnosis, Computer-Assisted↗
PubMed1992

[Endoscopic analysis of gastric mucosal lesions in patients with adult T-cell leukemia during chemotherapy].

Gastric mucosal lesions in 13 patients with adult T-cell leukemia (ATL) were endoscopically studied at least at 2 occasions during chemotherapy for these patients. X-ray examinations by using barium meal showed deformities in 10 patients and abnormal mucosal pattern in 11 out of 13 patients with ATL. The endoscopic examinations revealed gastric ulcers in 5 patients, erosion in 8, diffuse bleeding in 2, tumorous mucosal folds in one, and submucosal tumor in one patient. In 9 out of 12 ATL patients, pathological study revealed that ATL cells had invaded the mucosal area of the stomach. The ulcers and erosions were improved by chemotherapy in 3 out of 5 and 5 out of 8 patients, respectively, whereas the erosion was not reduced in 2 and even aggravated in one patient. Interestingly, the gastric lesions formed by ATL cell invasion were improved by the administration of anticancer agents in 5 out of 9 patients. However, these lesions reappeared together with systemic lesions of ATL.

Adult↗
PubMed1991

Purification and determination of the NH2-terminal amino acid sequence of mouse alpha-amylase secreted from Saccharomyces cerevisiae: correct processing of the secretion signal from pGKL killer 28 kDa precursor protein.

We have previously reported the construction of recombinant mouse salivary alpha-amylase secretion vector in Saccharomyces cerevisiae utilizing novel yeast secretion signal derived from killer 28 kDa precursor protein. Here, we have first purified recombinant mouse alpha-amylase to homogeneity from the culture medium of S. cerevisiae, and determined its NH2-terminal amino acid sequence. The sequencing data indicated that the 28 kDa killer secretion signal-alpha-amylase fusion protein was cleaved accurately at its native processing site, and that both the core-glycosylated and non-glycosylated alpha-amylases possessed the same NH2-terminal amino acid sequences.

Amino Acid Sequence↗
PubMed1991

Structure and structural change of the myosin head.

The ATPase site of myosin was located by three-dimensional electron microscopy using the avidin-biotin system. The site is about 5 nm from the tip of the myosin head, about 4 nm apart from the actin-binding site of myosin. Other functional sites on the myosin head were located by electron microscopy with the avidin-biotin system, monoclonal antibodies and site-directed antibodies. These findings enable us to estimate the domain structure of the head. The shape of the myosin heads was examined by electron microscopy using rotary-shadowing and uni-directional shadowing technique, and two types were seen: a straight one and a bent one. Bending occurs at 12 +/- 2 nm from the head-rod junction. This location corresponds with the images by three-dimensional electron microscopy and electron micrography of the crystal. The bending region locates at the boundary of domains. Bent heads increase in the presence of ADP-Vi. The location and angle of bending were almost the same under all the conditions examined. These findings suggest that the heads of straight and bent shapes are in equilibrium, and that ADP-Vi shifts the equilibrium to the bent shape. The bending of the myosin head may play an important role in the molecular mechanism of muscle contraction.

Animals↗
PubMed1991

Structural analysis of muscle thin filament.

Thin sheets of Ac-Tm-Tn paracrystals were prepared in the presence of high concentration of Ca2+ ion and three-dimensional image analysis was performed. The optical diffraction pattern of an electron micrograph showed spots up to 1/1.6 nm-1 in the radial direction and up to 1/2.5 nm-1 in the axial direction, the best resolution ever obtained so far. The translationally filtered image showed clear polarity of filament which looked like a "spearhead" per each crossover repeat of actin helix. The three-dimensionally reconstructed model looked very similar to the inner regions (A+B domains) of the Ac-Tm-S1 complex obtained by Toyoshima and Wakabayashi (14, 15) when they were placed so that the "spearhead" pattern of the Tc-Tm-Tn complex and the "arrowhead" pattern of the Ac-Tm-S1 complex pointed in the same direction. The myosin-binding site of actin was identified by comparison of the two structures. The model of actin molecule cut out from the thin filament model had a low density region within itself, which was located about 2.5 nm from the helix axis. That low density region divided actin molecule into two domains, a large and a small domain. A dense "pillar" was detected which connected two neighboring actin molecules along a left-handed generic helix 1 nm from the helix axis. Two actin-actin binding sites which were responsible for the connection through the "pillar" were located on the inner surface of actin molecule. To obtain better crystalline arrays of actin, we tried a method utilizing adsorption to lipid. A positively-charged monolayer of lipids was formed on the surface of a small volume of buffer solution which was put in a microwell. Solution of negatively-charged F-actin was then injected into the buffer solution and was allowed to be joined to the lipid monolayer by electrostatic attraction. Fluidity of the lipid monolayer enabled the two-dimensional crystallization of actin. Electron microscopy revealed that larger paracrystalline arrays were formed more rapidly (less than 1 hr) than those formed within solution, which demonstrated the advantage of this adsorption method.

Actins↗
PubMed1991

Detection of human T-cell leukemia virus type I proviral sequences from fixed tissues of seropositive patients.

Fixed lymphoma tissues from 11 patients seropositive for human T-cell leukemia virus type I (HTLV-I) antibodies were analyzed for proviral sequences by the polymerase chain reaction. Typical adult T-cell leukemia/lymphomas (ATLLs) from nine patients were positive for HTLV-I sequences. In contrast, one of two lymphomas with immunophenotypes atypical for ATLL was negative for HTLV-I. This HTLV-I DNA-negative lymphoma, although present in an HTLV-I-seropositive patient, was therefore reclassified. The HTLV-I tax gene was always detected in the ATLL tissues, whereas segments of the pol gene were not detected in half the cases. These studies demonstrate that fixed non-ATLL specimens can be distinguished from ATLL specimens.

Adult↗