Biomedical subjects

T Kosaka

Publications and source records attributed to T Kosaka.

At least 109 records · Page 6Linked to original sources

PubMed1997

Release of a newly-identified cysteine protease, tetrain, from Tetrahymena into culture medium during the cell growth.

Protease activity in the culture medium of Tetrahymena pyriformis markedly increased during the growth of the ciliate. The protease activity in the culture medium was purified by sequential column chromatographies. The purified protease had an apparent molecular mass of 28 kDa. N-terminal amino acid sequencing analysis suggested that the protease is a mature form of cysteine protease. Requirements of free sulfhydryl groups for activity and sensitivity to N-tosyl-L-phenylalanine chloromethyl ketone and Na-p-tosyl-L-lysine chloromethyl ketone also indicated that the protease is a member of the papain family of cysteine proteases. The protease was designated as tetrain. Immunoblotting analyses showed that tetrain was present in higher amount in the culture medium in the stationary phase than in the logarithmic phase. Tetrain has high activities at neutral to alkaline pH values. This suggests that tetrain has functional roles in the culture medium in the stationary phase, because the pH of the culture medium became alkaline with the progress of Tetrahymena growth.

Amino Acid Sequence↗

PubMed1997

Leukocytapheresis with leukocyte removal filter as new therapy for ulcerative colitis.

Leukocytapheresis (LCAP) with a leukocyte removal filter column was administered for 45 patients with ulcerative colitis (UC). We evaluated changes in the leukocyte count and the differential percentages during LCAP. Cytokine production was assessed from each patient's peripheral mononuclear cells or monocytes. Flow cytometry was performed to assess the removal rates of activated cells and adhesion molecule positive cells by LCAP. Clinical improvement was recognized in 35 of 45 patients during intensive LCAP therapy, and it continued throughout maintenance therapy in 32 patients (71.1%). The leukocyte count was decreased to about 40% during the first 30 min, but it increased to approximately 170% at 20 min after the completion of LCAP. The concentration of tumor necrosis factor (TNF)alpha before LCAP in the effective group was higher than it was in either the ineffective group or the control group. Its level decreased to near normal range after LCAP. In the effective group, the concentrations of interleukin (IL)-1beta, IL-2, interferon (IFN)gamma, and IL-8 were near the normal upper limits before LCAP; however, they had decreased after LCAP. The concentration of IL-4 increased after LCAP. In the ineffective group, in contrast, the concentrations had been at or near normal before the initial LCAP treatment. Flow cytometry study revealed that LCAP could remove the activated cells and adhesion molecule positive cells more effectively. The clinical improvement and the changes observed before and after LCAP therapy suggest that LCAP is able to intervene in the causal mechanism(s) of UC.

Blood Cell Count↗

PubMed1997

The beta APP717 Alzheimer mutation increases the percentage of plasma amyloid-beta protein ending at A beta42(43).

We measured plasma levels of amyloid beta protein (A beta) ending at positions 40 (A beta40) and 42(43) [A beta42(43)] in six carriers of beta APP717 (Val to Ile) mutation linked to familial Alzheimer's disease (FAD) as well as in patients with sporadic AD (sAD) and controls. The percentage and the level of A beta42(43) were significantly higher in carriers of beta APP717 mutation relative to sAD, whereas A beta40 levels were decreased. In contrast, A beta levels and ratios were at similar levels in sAD, regardless of the stage of the disease, compared with non-AD neurologic disease controls and nondemented control individuals. These results suggest that the reported increase in the percentage of A beta42(43) secretion in transfected cells with beta APP717 mutant genes actually takes place in the bodies of carriers of beta APP717 mutation, and that plasma A beta could be used as an indicator of the alterations of beta APP/A beta metabolism in subtypes of AD.

Adult↗

PubMed1997

[Studies on 5-lipoxygenase inhibitors. Synthesis of and structure--activity relationship in p-hydroxyarylalkenylbenzoazoles].

In a previous paper we reported that 2-(p-hydroxyarylbutadienyl)benzoxazoles are highly potent 5-lipoxygenase inhibitors. We synthesized their ethenyl homologues and benzothiazole derivatives, and evaluated their 5-lipoxygenase inhibitory activity in vitro with cell-free rat basophilic leukemia (RBL-1). In most cases the replacement of benzoxazolyl with benzothiazolyl resulted in an enhancement of the activity. All compounds with butadienyl spacers tested herein exhibited strong inhibitory activities. While most of the ethenyl homologues showed weaker activities than their corresponding butadienyl homologues, some ethenyl compounds in the benzothiazole derivatives were found to be as potent as their corresponding butadienyl homologues. The inhibitory activity was also affected by the variation in the p-hydroxyaryl functionality.

Animals↗

PubMed1997

Possible involvement of rapamycin-sensitive pathway in Bcl-2 expression in human neuroblastoma SH-SY5Y cells.

In human neuroblastoma SH-SY5Y cells, treatment with immunosuppressants such as FK506, cyclosporin A or rapamycin for 4 days induced the enhancement of the 27-kDa Bcl-2alpha protein level. Among immunosuppressants, rapamycin has most potency. Treatment with herbimycin A or wortmannin also enhanced Bcl-2 expression, but the BB type of platelet-derived growth factor decreased the level. These results suggest that Bcl-2 expression is probably regulated by the cascade of tyrosine kinase, phosphatidylinositol 3-kinase and rapamycin-sensitive p70 S6-kinase in human neuroblastoma SH-SY5Y cells.

Gene Expression↗

PubMed1997

[Remission by leukocytapheresis for a patient with ulcerative colitis found refractory by conventional drug therapies].

A 40-year-old male was admitted to our hospital on August 30, 1994 to receive a new ulcerative colitis (UC) therapy, leukocytapheresis (LCAP). On the admission day, he had bloody stool 5 to 6 times/day, abdominal pain, slight fever, and hypoproteinemia. His UC type was moderately severe left-sided colitis with pseudopolyposis. Prior to admission to our hospital, his condition had not improved for about 9 months, despite drug therapies such as salicylazosulphapyridine, intravenous high dose prednisolone, protease inhibitor, intraarterial hydrocortisone sodium succinate, 4 series of pulse therapies with metylpredonisolone, enema of corticosteroid, azathioprine (Imuran), and cyclosporine at another hospital. Thus he was introduced to our college hospital and treated by LCAP since September 1. After 10 LCAP sessions, remission was observed and the patient discharged on December 23. Until he was later operated on for heavy bleeding after he had discontinued treatment and had drunk heavily, he had maintained remission for 13 months with LCAP only once a month even after we gradually decreased the other medical supports and stopped all of them. After LCAP, the normalization of high percentage of leukocytes presented HLADR+ and lymphocytes presented CD 11 a+ CD 8+ was also observed. This suggests LCAP intercepts the excess immune reaction in UC by removing leukocytes.

Adult↗

PubMed1997

[Leukocytapheresis for ulcerative colitis].

Major inclusion criteria for leukocytapheresis (LCAP) therapy were mainly insufficient response to conventional drugs therapy. LCAP was administered once a week for 5 weeks of intensive therapy and once approximately a month for maintenance therapy, for 38 patients with UC. LCAP could remove approximately 1 x 10(10) white blood cells in each session. In the evaluation, we classified the response to the LCAP as: 1) excellent, 2) moderately improved, 3) no change, and 4) deterioration. Clinical improvement was recognized in 29 of 38 patients (76%) including 8 with dramatic response during the intensive therapy, and continued throughout the maintenance therapy in 26 patients (68.4%). Even though their symptoms were mild, the patients with more than 5 years UC history seemed to be not effective. The patients with moderately improvement and with excellent response have kept remission for about 20 months and about 2.5 years on an average, respectively. Clinical and blood examinations showed no side effects in any cases. It suggests that LCAP is able to be a UC treatment between drug therapies and an operation.

Adult↗

PubMed1997

[Radiation therapy for advanced gastric cancer].

Thirteen patients with advanced gastric cancer treated by palliative radiotherapy were retrospectively analyzed. The radiation sites were abdominal cavities in 8 cases, superficial masses in 5 and lung metastasis in one. The purposes were to diminish mass size in 5 cases, to relieve pain in 3 and to reduce stenosis in 6. The total doses were more than 40 Gy in 10 patients. In 2 cases, the intracavitary irradiation was performed using 192Ir. In one case, radiation had to be stopped at the dose of 22.5 Gy because of poor general condition. Partial response was obtained in 6 of 12 cases (RP, 50%). The sites of responders were superficial lesions in 4 and hepatic hilar mass in 2, which were given intracavitary as well as external radiation. Pain relief was achieved in all patients suffering from it. One of 3 cases with esophageal stenosis showed marked improvement in swallowing. Two patients showed a decrease in the levels of tumor markers. Five patients had side effects of more than grade 2. Two of them were grade 3, one thrombocytopenia and one diarrhea. The median survival time of all cases was 9 months, and 5 patients could shift to home care. These results suggest that palliative radiotherapy could be one of the most useful locoregional therapies for advanced gastric cancer, in the aspect of improvement of patient's QOL.

Aged↗

PubMed1996

Persistence of hepatitis C virus RNA in established human hepatocellular carcinoma cell lines.

The persistence of the viral RNA of hepatitis C virus (HCV) was examined in 13 hepatocellular carcinoma (HCC) and two hepatoblastoma cell lines by reverse transcription followed by the polymerase chain reaction (RT-PCR). HCV RNA was detected in three HCC lines (JHH-1, JHH-4, and JHH-6) and negative-strand viral RNA was found in JHH-4, indicating that there is a putative replicative intermediate of HCV in JHH-4 cells. To rule out the possibility of contamination, the partial nucleotide sequences of HCV-specific PCR products of these three cell lines were determined. The clone from JHH-1 belonged to genotype 1 (1a or 1b), and the clones from JHH-4 and JHH-6 belonged to genotype 2b, but their sequences differed from each other. These cell lines may be useful for studies related to HCV.

Adolescent↗

PubMed1996

Distribution of calretinin immunoreactivity in the mouse dentate gyrus. I. General description.

Calretinin-containing elements were visualized with immunocytochemistry in the adult mouse dentate gyrus (DG). In the ventral DG calretinin immunoreactive (CR-IR) large multipolar cells were clustered; they extended between two and four thick cylindrical dendrites which further branched into several thinner processes. Characteristic grape-like spiny appendages were occasionally observed on these thick and thinner dendritic processes. On the basis of these structural features these large CR-IR cells were identified as hilar mossy cells. At the supragranular zone a dense CR-IR band was seen, where numerous CR-IR punctae and fibers were packed tightly among putative granule cell dendrites. In the granule cell layer, especially at the dorsal DG, numerous faintly CR-IR cells were located at the interface with the hilus. They were triangular in shape and neither calbindin D28k nor GABA positive, but were immunoreactive for highly polysialylated neural cell adhesion molecule (NCAM-H) and thus considered as newly generated neurons. In the molecular layer CR-IR cells were also scattered; they were mainly located near the pial surface and the hippocampal fissure, small in size, ovoid in shape and usually gave rise to one very thin axon-like and one thin cylindrical dendritic process. These cells were assumed to be Cajal-Retzius cells. Throughout the layers, that is, the molecular layer, the granule cell layer and the hilus, CR-IR multipolar and/or fusiform cells were encountered. They resembled those reported in the rat DG in their structural features and usually extended smooth or varicose or sparsely spiny dendritic processes; some of them were confirmed to be GABA-like immunoreactive and/or glutamic acid decarboxylase immunoreactive. The present study showed that CR immunoreactivity in the mouse DG differed significantly from that in the rat and monkey dentate gyri reported previously.

Animals↗

PubMed1996

Synapses in the granule cell layer of the rat dentate gyrus: serial-sectioning study.

Synaptic contacts on the granule cell somata as well as on their axon initial segments in the dentate gyrus of one juvenile 5-week-old rat and one adult 12-week-old rat were analyzed in an electron microscopic serial-sectioning study. In the dentate gyrus of the juvenile rat, somata of 17 granule cells were nearly completely reconstructed from a series of 183 serial sections, and the axon initial segments of 15 of these granule cells were traced in various lengths. On the other hand, in the dentate gyrus of the adult rat, somata of 31 granule cells were almost completely reconstructed from a series of 238 serial sections, and the axon initial segments of 23 of these granule cells were traced in various lengths. Both symmetrical and asymmetrical synapses were observed on the somata, whereas almost all synapses on the axon initial segments were of symmetrical type and asymmetrical synapses on the axon initial segments were rather exceptional. Although we confirmed two conclusions from previous random-section studies to some extent, that is, the superficial-to-deep gradient of synaptic densities on granule cell somata and the presence of a substantial number of asymmetrical synapses on granule cell somata (about 23% of total somatic synapses), the present serial-sectioning study clearly revealed that granule cells vary greatly with regard to the number of synapses on their somata (15-186 in a 5-week-old rat and 9-144 in a 12-week-old rat) and axon initial segments. The granule cells also differed in the proportion of somatic asymmetrical synapses to total synapses they received (0-44% in a 5-week-old rat and 0-60% in a 12-week-old rat). The results of the present study indicated that, when a relatively small number of granule cells are analyzed, one should take the heterogeneity of synaptic contacts on granule cells in number and type into consideration.

Animals↗

PubMed1996

Establishment and characterization of a human colon cancer cell line, OUMS-23, from a patient with familial adenomatous polyposis.

A human colon carcinoma cell line designated OUMS-23 has been established from metastatic pericardial fluid of a male familial adenomatous polyposis patient with colon cancer. Since 1984, the epithelial cells have been maintained in culture. Ultrastructural studies revealed the presence of numerous microvilli on the cell surface and desmosomes between the adjacent cells. The cells secreted carcinoembryonic antigen into the culture medium (15 ng/10(6) cells-1 24 h-1). The cells expressed heat-stable placental-type-like alkaline phosphatase, whereas the normal counterparts expressed tissue-unspecific alkaline phosphatase. Karyotypic analysis showed that the cell line was of human origin and that the chromosome number was broadly distributed between 53 and 118. Southern blot analysis of the APC gene revealed no abnormalities in OUMS-24 cells, while Northern blot analysis demonstrated that the expression of the gene was about one-half that of the normal human fibroblasts. No mutations at the "hot spots" of codons 12 and 61 of H-, K- and N-ras proto-oncogenes were detected in the cells. The cells could grow in soft agar at a cloning efficiency of 6.5%, and upon transplantation into nude mice the cells formed tumors, which were diagnosed as differentiated adenocarcinoma.

Adenomatous Polyposis Coli↗

PubMed1996

Gallbladder cancer associated with cholesterosis.

We report herein two cases of carcinoma in situ of the gallbladder associated with cholesterosis. The patient in case 1 was an 81-year-old man who underwent a cholecystectomy for cholelithiasis. The resected specimens revealed gallbladder cancer in the fundus which was diagnosed histologically as mucinous carcinoma. Other findings included 13-mm, 12-mm, and 5-mm polypoid lesions in the neck of the gallbladder which macroscopically appeared to be cholesterol polyps, but histologically demonstrated carcinoma in situ with cholesterosis. The patient in case 2 was a 76-year-old man in whom ultrasonography revealed a highly echogenic, elevated lesion in the gallbladder. Cholecystectomy was performed, and a 33 x 28-mm papillary, elevated lesion with cholesterosis was resected from the neck of the gallbladder. Histologically, this was demonstrated to be papillary adenocarcinoma in situ with cholesterosis surrounded by glandular dysplasia. The distribution of the carcinomas and cholesterosis in both of these patients suggests that the adenoma or carcinoma of the gallbladder had occurred first. Then, the tumor epithelium absorbed cholesterol from the bile, and foamy cells were produced. Thus, when treating cholesterol polyps, it should be remembered that it is often difficult to distinguish between cholesterol polyp and gallbladder cancer with cholesterosis.

Adenocarcinoma, Mucinous↗

PubMed1996

Age-related changes in the immunoreactivity of the monocyte/macrophage system in rat molar pulp.

Defence reactions of the dental pulp potentially involve a variety of immunocompetent cells, particularly class II major histocompatibility complex (MHC)-expressing cells and macrophages. In order to examine how the immunodefence potential of the pulp changes as a function of age, phenotypic distribution of pulpal cells expressing immunoreactivity to monoclonal antibody ED1 (reactive with nearly all macrophages and dendritic cells) was examined immunohistochemically in the lower first molars of developing (new-born to 10-week-old), adult (14-24-week-old) and aged (1-1.5-yr-old) Wistar rats. During tooth development, increasing numbers of ED1+ cells in the pulp also expressed immunoreactivity to ED2 (reactive with a differentiation-related antigen present on resident macrophages). ED1+ and ED2+ cells were distributed throughout the pulp before the tooth formation was completed. OX6+ (class II MHC-expressing) cells started to increase in number shortly after the eruption of the tooth and the increase continued even after the tooth formation had been completed. In aged rats, the density of the pulpal ED1+ cells was maintained at a relatively high level, whereas a significant decrease in the density of OX6+ cells was observed. These results indicate that the density and composition of pulpal cells expressing macrophage-associated antigens vary with increasing age, which most probably is related to changes in the immunological defence potential of the pulp against infection.

Aging↗

PubMed1996

Characterization of natural killer cytotoxic factor (NKCF) from canine NK cells.

We investigated the presence of canine natural killer cytotoxic factor (NKCF). Canine natural killer (NK) cell-mediated cytotoxicity measured by 51chromium (51Cr) release assay was found to be highest in the T-cell population, which was fractionated into the 35-40% Percoll fraction by discontinuous gradient centrifugation. The cytotoxicity of NKCF in the culture supernatant showed a similar tendency to NK activity. Release of NKCF was rapid after contact with target cells, and reached a plateau in 60 min. The cytotoxicity of NKCF could be detected within at least 15 min in coculture with CL-1 target cells, reaching a plateau in 60 min. We also characterized canine NKCF and found it to be a protein, which was stable against both heat and cold treatment. These findings suggest that canine NK cells release NKCF immediately after recognition and binding to the target cell, and that NKCF plays an important role in canine NK-mediated cytotoxicity.

Animals↗

PubMed1996

The distribution of two calcium binding proteins, calbindin D-28K and parvalbumin, in the entorhinal cortex of the adult mouse.

The immunohistochemical localization of two specific calcium binding proteins, parvalbumin (PV) and calbindin D-28K (CB), were examined in the entorhinal cortex (EC) of the adult mouse. The PV and CB immunoreactivities exhibited a conspicuous regional and laminar distribution in the EC. The overall immunostaining pattern of PV and CB appeared to be complementary in the EC, especially in the medial entorhinal area (MEA). In the dorsal MEA, although layer 2 showed intense PV and CB immunostaining, the PV immunoreactivity was denser in layers 3, 5 and 6a than in layers 4 and 6b, whereas the CB immunoreactivity was denser in layers 4 and 6b than in layers 3, 5 and 6a. Moreover, we recognized the dorsoventral gradation of the PV and CB staining that is, in the dorsal to ventral direction, the intensity of the PV immunostaining in layers 2, 3, 5 and 6a gradually decreased whereas that of the CB immunostaining in those layers gradually increased. In addition, a similar dorsoventral gradation was also observed in the number of PV immunoreactive (PV-IR) and CB-IR neurons in layer 3. In layer 2 of the MEA, the CB-IR neurons were clustered, while displaying a patch-like pattern which could not be recognized in either Nissl staining or PV staining. In contrast, layer 2 of the LEA was separated into two sublayers, the superficial sublayer 2a and the deeper sublayer 2b; both of these sublayers consisted of cell clusters recognized by Nissl staining. These sublayers showed a prominent difference in their CB immunoreactivity; the cells in the layer 2a clusters were CB negative, whereas the cells in the layer 2b clusters were CB-IR. Furthermore, we also recognized a particular region at the most medial part of the MEA, where layer 2 was different from the other portion of the MEA regarding CB immunoreactivity and the cells containing another calcium binding protein, calretinin, were clustered in layer 3. Both the adjacent section technique and the fluorescent double-staining technique clearly revealed that a relatively large number of presumable interneurons contained both PV and CB immunoreactivities. Furthermore, the three neuron groups that were immunoreactive for both PV and CB, immunoreactive for PV alone and immunoreactive for CB alone were heterogeneous in their structural features such as shape and size, and no particular difference was found in their structural features among these three groups.

Age Factors↗

PubMed1996

Electron microscopic serial-sectioning/reconstruction study of parvalbumin-containing neurons in the external plexiform layer of the rat olfactory bulb.

Neurons containing a calcium-binding protein parvalbumin in the external plexiform layer of the rat olfactory bulb were identified light microscopically with the pre-embedding immunocytochemistry and were subsequently analysed with the electron microscopic serial-sectioning and three-dimensional reconstructions. In the present study we chose several different types of parvalbumin-immunoreactive neurons identified light microscopically as Van Gehuchten cell type, superficial short-axon cell type and multipolar cell type. Parvalbumin-immunoreactive somata were similar to one another in their ultrastructural characteristics, showing nuclear indentations, moderately developed Golgi apparatus and abundant mitochondria; these structural features appeared to resemble those of the short axon cells around the glomeruli and in the granule cell layer reported in previous electron microscopic studies. All neurons analysed in the present study made symmetrical synapses on to dendrites and somata of presumed mitral/tufted cells and received asymmetrical synapses from them, and occasionally formed reciprocal synapses with them. On the parvalbumin-immunoreactive processes, the asymmetrical synapses nearly equalled the symmetrical ones in number and about 30-50% of them were identified as reciprocal pairs. In contrast, no presynaptic sites were observed on parvalbumin-immunoreactive somata, and thick portions (more than approximately 2 microns in diameter) of the proximal dendrites, where they were occasionally postsynaptic in some asymmetrical and symmetrical synapses from parvalbumin-immunonegative profiles. Characteristically, parvalbumin-immunoreactive process frequently make direct contacts with one another; processes regarded light microscopically as arising from a soma or a dendrite or parvalbumin-immunoreactive neurons were sometimes revealed to be separate but directly contacting processes with electron microscopic examinations. Although puncta adherentia were occasionally observed between these contact sites, so far neither gap junctions nor chemical synapses were observed. Until now, it has been believed that in the external plexiform layer only granule cells form reciprocal synapses with mitral/tufted cells. However, the present study clearly demonstrates that interneurons different from granule cells, namely GABAergic neurons containing a calcium-binding protein parvalbumin, also make reciprocal synapses with mitral/tufted cells in the external plexiform layer. Therefore, neuronal processes making reciprocal synapses with mitral/tufted cells in the external plexiform layer cannot be determined a priori as granule cell processes.

Animals↗

PubMed1996

Kinetics of macrophages and lymphoid cells during the development of experimentally induced periapical lesions in rat molars: a quantitative immunohistochemical study.

Quantitative phenotypical analysis for macrophages and lymphoid cells was made on periapical lesions induced by making unsealed pulp exposures in rat molars. Exudative macrophages of diverse morphology were the most dominating immunocompetent cells during all experimental periods. They exhibited almost complete distribution through the periapical lesions by the onset of active lesion expansion, and their kinetics and morphology were considerably similar to Ia+ non-lymphoid cells. Lymphoid cells started to show a notable increase shortly before the onset of active lesion expansion. CD4+ lymphocytes dominated at first, whereas CD8+ lymphocytes and plasma cells were dominant when the lesion size was stabilized. These findings suggest that macrophages of heterogenous populations play essential roles in the lesion pathogenesis by acting, depending on their functional heterogeneity, as effector cells or as antigen-presenting cells that stimulate CD4+ lymphocytes to induce an immune response. Interactions between plasma cells and CD8+ lymphocytes may be related to lesion chronicity.

Animals↗