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Biomedical subjects

K Masuda

Publications and source records attributed to K Masuda.

At least 217 records · Page 12Linked to original sources
PubMed1998

Thrombospondin 2 gene expression is correlated with decreased vascularity in non-small cell lung cancer.

Stromal vascularity is thought to be a major factor involved in the progression of carcinoma. However, the crucial mechanisms of vascularization in the stroma are not well understood. Vascularity could be regulated by various cytokines produced by neoplastic or stromal cells in carcinoma. Thrombospondin (TSP) has an inhibitory role against vascularization in vitro, although the biological significance of TSP has not been characterized in vivo. We examined expression of TSP1 and TSP2 genes in 78 non-small cell lung cancers (NSCLCs) and 33 extraneoplastic lung tissue samples by reverse transcription-PCR. TSP1 expression was detected in 66.7% (52 of 78) of NSCLCs and in 69.7% (23 of 33) of extraneoplastic lung tissue specimens. TSP2 expression was seen in 48.7% (38 of 78) of NSCLCs, whereas 72.7% (24 of 33) of extraneoplastic lung tissue samples showed TSP2 gene expression. TSP2 expression was significantly decreased in NSCLC as compared with extraneoplastic lung tissue (chi2 test, P=0.019). Vascularity in the NSCLC was inversely correlated with TSP2 gene expression (Mann-Whitney U test, P=0.009). Patients with adenocarcinoma positive for TSP2 gene expression (22 of 49) showed significantly better prognosis than those without TSP2 (27 of 49; Cox-Mantel test, P=0.034). TSP1 expression showed no apparent correlation with these factors. These results suggested that TSP2 had an inhibitory role against vascularization and progression of NSCLC.

Carcinoma, Non-Small-Cell Lung↗
PubMed1998

[A phantom study for the evaluation of the effect of the high uptake in the liver on technetium-99m myocardial perfusion SPECT images].

The purpose of this study was to evaluate influences of the high hepatic uptake on parameters such as filtering, attenuation coefficient, and scatter correction at reconstructing of the myocardial SPECT images. Hepatic and cardiac spaces of a myocardial phantom (RH-2, Kyoto Kagaku), were filled with technetium-99m and a three-detector SPECT system (GCA 9300-DI, TOSHIBA) was used. The hepatic activity's influence was estimated from a qualitative percent regional scattering and the effects of attenuation and scatter correction were evaluated by a circumferential profile curve. Percent regional scattering increased in reverse to hepato-cardiac distance (HCD) and in proportion to hepatic to cardiac activity ratio (HCR). This tendency was observed the most significantly in the inferior region, followed by in the lateral, anterior and septal regions, declining in this order. An artifactual defect adjacent to the liver was observed when HCR is three and HCD is zero. However, when the Butterworth filter was used with small filtering-sizes and lower orders in combination with attenuation and scatter correction, the defects were decreased up to 15% at counts in the inferior region. This study showed that the hepatic to cardiac activity ratio, and the hepatocardiac distance should be considered for reconstruction of the SPECT images.

Artifacts↗
PubMed1998

[Preventive effects of diclofenac ophthalmic solution on post-cataract-surgical cystoid macular edema].

Using eyes undergoing phacoemulsification followed by implantation of a foldable acrylic intraocular lens (IOL) designed for small-incision cataract surgery, a multi-center study was performed to compare a non-steroidal ophthalmic solution (0.1% diclofenac) to a steroidal ophthalmic solution (0.1% fluorometholone) in preventing cystoid macular edema (CME) and inducing disruption of the blood-aqueous barrier determined by laser flare cellmetry. The incidence of CME, noted in 3 out of 53 eyes (5.7%) receiving diclofenac and in 29 out of 53 eyes (54.7%) receiving fluorometholone, was significantly lower in the diclofenac group. The flare in the anterior chamber was also significantly lower in the diclofenac group; when compared between eyes with and without CME, the amount of flare was significantly higher in the former group. These findings suggest that diclofenac effectively prevents CME following cataract surgery and that CME is closely related to the breakdown of the blood-aqueous barrier.

Aged↗
PubMed1998

[Evaluation of clinical utility of 99mTc-MIBI scintigraphy in the localization of thyroid, breast and lung/mediastinum tumors--a report of multicenter phase III clinical trials].

Phase III clinical study in 136 patients diagnosed or strongly suspected of thyroid, lung/mediastinum or breast cancer was performed to determine clinical utility of 99mTc-MIBI in the localization of tumors, and the results in 135 were evaluated. Except taste peculiar in 43 patients and nausea in one, no adverse events were reported. Seven abnormal changes in vital signs and 27 in clinical laboratories were noted, which were all judged as having no or unlikely relationship to the agent. Out of 177 malignant lesions, 156 (88%) were detected with 99mTc-MIBI regardless of their histology or location. Of 6 benign tumors, 3 were detected. Fifteen sites of false positive in 11 malignant tumor patients and 5 sites in 6 patients with non-tumor disease were observed. Our study indicates that 99mTc-MIBI is a safe and excellent agent for the localization of tumors. Especially, the fact that 99mTc-MIBI detected remote metastatic lesions with high sensitivity is a great advantage over the other conventional imaging modalities.

Adult↗
PubMed1997

Metabolism of the extracellular matrix formed by intervertebral disc cells cultured in alginate.

STUDY DESIGN: Cells from normal rabbit nucleus pulposus (NP) and anulus fibrosus (AF) were cultured in alginate beads for as long as 14 days to allow them to reform a matrix made up of two compartments: the cell-associated matrix (CM) and further removed matrix (FRM). At different time points, the CM and FRM made by each cell population were analyzed using histologic, biochemical, and immunologic assays. OBJECTIVES: To study the metabolism of normal rabbit NP and AF cells in alginate by characterizing the CM and FRM formed by each cell population, and to identify metabolic properties that may shed light on mechanisms at play in disc degeneration. SUMMARY OF BACKGROUND DATA: Little is known about the metabolism of intervertebral disc cells, in part because of the lack of microculture systems appropriate for the study of these cells in vitro. In recent studies from our laboratories, it was suggested that articular chondrocytes cultured in alginate beads remain phenotypically stable and reform a matrix similar to the one they populate in vivo. This culture system appears ideally suited for the study of intervertebral cells available only in limited numbers. METHODS: Rabbit NP and AF cells released from the matrix by sequential enzyme digestion were encapsulated in alginate beads (20,000 cells/bead) and cultured for as long as 14 days. At selected time points, beads were solubilized with calcium chelating agents, and the CM and FRM were isolated. The rate of 35S-sulfate incorporation into proteoglycans, and the contents of various extracellular matrix molecules (total sulfated proteoglycans, antigenic keratan sulfate, hyaluronan, collagen, and pyridinium crosslinks) were measured. RESULTS: Both NP and AF cells remained phenotypically stable in the alginate gel throughout the culture period and reestablished a matrix composed of CM and FRM compartments. The two cell populations exhibited numerous differences in their metabolic activities in vitro. Nucleus pulposus cells synthesized fewer proteoglycan and collagen molecules and were less effective in incorporating these into the CM than AF cells. CONCLUSIONS: Intervertebral disc cells, especially NP cells, are extremely sluggish in reforming a CM, a protective shell rich in proteoglycans and collagen molecules. This may help explain why damage to the NP often is accompanied by progressive degeneration of the disc in vivo.

Alginates↗
PubMed1997

Primary non-Hodgkin's lymphoma of the lacrimal sac: a case report and a review of the literature.

BACKGROUND: Primary non-Hodgkin's lymphoma of the lacrimal sac is extremely rare, with most reported cases representing secondary involvement of a systemic malignancy. METHODS: The clinical record of a 70-year-old female who presented with epiphora and swelling of the lacrimal sac area is described. A review of the literature of patients with primary lacrimal sac lymphoma also is presented. RESULTS: Computed tomography demonstrated a lacrimal sac mass involving the nasolacrimal canal. Histopathologic examination of a biopsy specimen revealed a diffuse large cell lymphoma. Using immunohistologic staining, the tumor was a B-cell type, similar to those described in the literature. The patient was treated with 50 gray of irradiation and chemotherapy with cyclophosphamide, doxorubicin, vincristine, and prednisone. The patient remained free of lymphoma 26 months after initial treatment. An ocular examination was unremarkable except for epiphora. CONCLUSIONS: Radiotherapy and/or chemotherapy can treat localized lymphoma of the lacrimal sac successfully.

Aged↗
PubMed1997

Characterization of UT2 cells. The induction of peroxisomal 3-hydroxy-3-methylglutaryl-coenzyme a reductase.

In the liver 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase is present not only in the endoplasmic reticulum but also in the peroxisomes. However, to date no information is available regarding the function of the peroxisomal HMG-CoA reductase in cholesterol/isoprenoid metabolism, and the structure of the peroxisomal HMG-CoA reductase has yet to be determined. We have identified a mammalian cell line that expresses only one HMG-CoA reductase protein and that is localized exclusively to peroxisomes. This cell line was obtained by growing UT2 cells (which lack the endoplasmic reticulum HMG-CoA reductase) in the absence of mevalonate. The cells exhibited a marked increase in a 90-kDa HMG-CoA reductase that was localized exclusively to peroxisomes. The wild type Chinese hamster ovary cells contain two HMG-CoA reductase proteins, the well characterized 97-kDa protein, localized in the endoplasmic reticulum, and a 90-kDa protein localized in peroxisomes. The UT2 cells grown in the absence of mevalonate containing the up-regulated peroxisomal HMG-CoA reductase are designated UT2*. A detailed characterization and analysis of this cell line is presented in this study.

Animals↗
PubMed1997

Neural networks analysis of astrocytic gliomas from MRI appearances.

A three-layered backpropagation neural network was developed to differentiate malignant from benign brain tumors in a group of patients with astrocytic gliomas. The MRI findings of 43 patients were reviewed before biopsy by three neuroradiologists independently. This provided a database made up of 129 patients' records each of which comprised 13 parameters derived from pre- and post-contrast MR images. The network's generalizing ability was then tested to predict the outcome of biopsy in 36 new cases and its performance compared to that of radiologist using ROC analysis. The output of the network with and without radiologists' impression yielded a better diagnostic performance with relative ROC areas of 0.94 and 0.91, respectively; compared to 0.84 obtained by radiologist. These results demonstrate that the neural network can effectively differentiate malignant from benign brain tumors.

Algorithms↗
PubMed1997

Characterization of monoclonal antibodies recognizing different fragments of cartilage oligomeric matrix protein in human body fluids.

Cartilage oligomeric matrix protein (COMP) is a high-molecular-weight glycoprotein found at a high concentration in articular cartilage. Recent studies have shown that the joint fluid and serum levels of antigenic COMP, measured by an enzyme-linked immunosorbent assay (ELISA) which uses a polyclonal antiserum raised against bovine COMP, provide important information about metabolic changes occurring in the cartilage matrix in joint disease. In this report, we describe the specificity of three monoclonal antibodies (mAbs) to human COMP and their usefulness in quantifying antigenic COMP fragments in body fluids. Two of the mAbs (16-F12 and 18-G3) recognized both oligomeric and monomeric forms of COMP, but the third (17-C10) reacted positively only with the former. Immunoblots of human COMP, predigested with trypsin for up to 6 h, showed that the three mAbs are directed against different epitopes identified on small tryptic fragments of 30 kDa (16-F12), 25 kDa (17-C10), and 40 kDa as well as 30 kDa (18-G3), respectively. The antibodies also recognized a different pattern of fragments in human pathological synovial fluids. This was particularly striking in the case of the medium size fragments (16-F12: 90 and 110 kDa; 17-C10: 70 and 90 kDa; 18-G3: up to five bands from 70 to 130 kDa). Competitive indirect inhibition ELISAs developed with mAbs 16-F12 and 17-C10 revealed further differences in the specificities of these antibodies. Thus, while mAb 16-F12 can be used only to quantify antigenic COMP in human synovial fluid and serum, mAb 17-C10 is useful in addition when analyzing canine and horse synovial fluid as well as canine serum. The results of analyses of synovial fluid samples from patients with osteoarthritis and rheumatoid arthritis provided preliminary evidence in support of the contention that measurement of the different COMP epitopes recognized by these mAbs in body fluids could prove useful in the clinical assessment of patients with joint disease.

Animals↗
PubMed1997

Peripheral framework of carrot cell nucleus contains a novel protein predicted to exhibit a long alpha-helical domain.

A monoclonal antibody, CML-1, raised against carrot (Daucus carota L.) nuclear-matrix proteins selectively labeled the nuclear periphery of carrot protoplasts when visualized by confocal and electron microscopy. To identify the constituent proteins of higher plant cells structurally homologous to the vertebrate nuclear lamina, we cloned overlapping cDNAs partially encoding a CML-1-recognized protein and determined the entire sequence including the open reading frame. When the deduced amino acid sequence was compared with other known protein sequences contained in major databases, no protein was found to show high sequence identity across the whole region of the protein, while the partial sequence showed strong similarities with myosin, tropomyosin, and some intermediate filament proteins. The protein, designated NMCP1, had an estimated molecular mass of 133.6 kDa and showed three characteristic domains. The central domain contains long alpha-helices exhibiting heptad repeats of apolar residues, demonstrating structural similarity to that of filament-forming proteins. The terminal domains are predominantly nonhelical and contain potential sequence motifs for nuclear localization signals. NMCP1 has many recognition motifs for different types of protein kinases, including cdc2 kinase and PKC. These results suggest that NMCP1 protein forms coiled-coil filaments and is a constituent of the peripheral architecture of the higher plant cell nucleus.

Amino Acid Sequence↗
PubMed1997

Differential N-glycan patterns of secreted and intracellular IgG produced in Trichoplusia ni cells.

Structures of the N-linked oligosaccharide attached to the heavy chain of a heterologous murine IgG2a produced from Trichoplusia ni (TN-5B1-4, High Five) insect cells were characterized. Coexpression of the chaperone immunoglobulin heavy chain-binding protein (BiP) in the baculovirus-infected insect cells increased the soluble intracellular and secreted IgG level. This facilitated the detailed analysis of N-glycans from both intracellular and secreted IgG. Following purification of the immunoglobulins using Protein A-Sepharose, glycopeptides, prepared by trypsin-chymotrypsin digestion, were further digested with glycoamidase from sweet almond emulsin to obtain the oligosaccharide moieties. The resulting oligosaccharides were then reductively aminated with 2-aminopyridine and the structures identified by two-dimensional high performance liquid chromatography mapping (Tomiya, N., Awaya, J., Kurono, M., Endo, S., Arata, Y., and Takahashi, N. (1988) Anal. Biochem. 171, 73-90). The N-glycans obtained from the secreted IgG contain 35% complex type, some with terminal galactose residues at either alpha1, 3-Man or alpha1,6-Man branches of the Man3GlcNAc2 core. The remaining oligosaccharides detected in the secreted IgG were principally hybrid (30%) and paucimannosidic (35%) type N-glycans. Most (84%) of these secreted glycoforms contained fucose alpha1, 6-linked to the innermost GlcNAc residue and the presence of a potentially allergenic fucose alpha1,3-linked to the innermost GlcNAc residue was also detected. In contrast, the intracellular immunoglobulins included 50% high mannose-type N-glycans with lower levels of complex, hybrid, and paucimannosidic-type structures. Reverse phase one-dimensional high performance liquid chromatography analysis of the IgG N-glycans in the absence of heterologous BiP exhibited a similar distribution of intracellular and secreted glycoforms. These studies indicate that Trichoplusia ni TN-5B1-4 cells are capable of terminal galactosylation. However, the processing pathways in these cell lines appear to diverge from mammalian cells in the formation of paucimannosidic structures, in the presence of alpha1,3-fucose linkages, and in the absence of sialylation.

Animals↗
PubMed1997

Phenotypes and invariant alpha beta TCR expression of peripheral V alpha 14+ NK T cells.

A novel subset of peripheral T cells, peripheral NK T cells, is found to be a major population comprising 5% of splenic T and 40% of bone marrow T cells. The majority of peripheral NK T cells are characterized by the expression of an invariant TCR-alpha encoded by V alpha 14/J alpha 281 with a one nucleotide N region. Moreover, a specific reduction of V alpha 14+ NK T cells has been demonstrated to be tightly associated with various autoimmune diseases, indicating their decisive role in autoimmune disease development. In this study, we investigated the phenotypes of peripheral V alpha 14+ NK T cells and their TCR-beta repertoire. Peripheral V alpha 14+ NK T cells, comprise two populations, i.e., small and large sized cells, at an equal frequency, belonged to the CD4- CD8- fraction, and are heat stable antigen(bright), macrophage-1bright, B220bright, CD45RBdim, and Mel-14dim, but CD5-, distinct from thymic NK T cells. TCR-beta analysis clearly showed that peripheral V alpha 14+ NK T cells utilized two to three dominant invariant TCR-beta, such as V beta 8.2 D beta J beta 2.5/V beta 7 D beta J beta 2.1 in the spleen and liver, V beta 8.2 D beta J beta 2.5/V beta 8.3 D beta J beta 2.2/V beta 7 D beta J beta 2.6 in the bone marrow, and V beta 7 D beta J beta 2.1/V beta 3 D beta J beta 1.2 in intestinal intraepithelial lymphocytes. Judging from the unusual surface phenotypes, such as heat stable antigen, macrophage-1, B220, CD45RBdim, and Mel-14dim, which are known to be T cell activation markers, peripheral V alpha 14+ NK T cells may always be activated under physiologic conditions, resulting in the oligoclonal expansion of V alpha 14+ NK T cells with different invariant TCR-beta in different peripheral organs. The unique features of V alpha 14+ NK T cells are discussed.

Amino Acid Sequence↗
PubMed1997

Cleavage of amino acid residue(s) from the N-terminal region of alpha A- and alpha B-crystallins in human crystalline lens during aging.

The current study reports for the first time a post-translational modification at the N-terminal region of alpha A- and alpha B-crystallins in normal human lens. The post-translational modification involves a loss of amino acid residues from the N-terminal region. We found three types of losses of N-terminal amino acid(s) from alpha-crystallin. One is the loss of the N-terminal amino acid residues 1-3 from alpha A-crystallin in aged lenses of the age 70 group. The other two modifications were found in alpha B-crystallin. One is the loss of Met(1) of the N-terminus and the other is the loss of 6 amino acids from the N-terminal region. These phenomena were observed in the lenses > 40 age group. Recent studies suggest that the N-terminal region of alpha-crystallin may play a chaperone-like role at the molecular level. These losses of amino acids from the N-terminal region may affect this molecular chaperone-like activity as well as the transparent properties of the human lens.

Aging↗
PubMed1997

B cell epitope mapping of the bacterial superantigen staphylococcal enterotoxin B: the dominant epitope region recognized by intravenous IgG.

We showed that i.v. IgG contains Abs against a major group of bacterial superantigens, and that they can inhibit superantigen-elicited T cell activation. The B cell epitope region of the superantigen and the inhibitory mechanism have remained unknown. To analyze the dominant B cell epitopes on the bacterial superantigen SEB (staphylococcal enterotoxin B), we constructed fusion proteins of SEB deletion mutants, and the reactivities of these recombinant proteins to i.v. IgG and healthy human sera were evaluated by means of immunoblotting. Intravenous IgG and healthy human sera mostly recognized the C-terminal fragment (amino acid (aa) 133-239). The C-terminally truncated protein (aa 1-228) and the truncated mutant delta 225-234 lost reactivity, while the truncated protein (aa 1-234) did not, suggesting that the region (aa 225-234) is the dominant B cell epitope. The mutant, in which residues 226-229 of SEB were exchanged for residues 209-212 of streptococcal pyrogenic exotoxin A, reduced the reactivity with the C-terminal region-specific IgG purified by affinity chromatography. The C-terminal region-specific IgG inhibited SEB-elicited T cell activation, suggesting that this Ab that recognizes the epitope functions as the humoral defensive factor against SEB in humans. Furthermore, the assumed epitope region was homology to the residues (aa 32-41) of human thymopoietin, containing the biologic active site.

Amino Acid Sequence↗
PubMed1997

Reduced susceptibility to Fas-mediated apoptosis in B-1 cells.

Elimination of activated T and B cells by Fas-dependent apoptosis may contribute to the maintenance of peripheral tolerance. CD40 ligation was recently shown to up-regulate Fas expression and enhance susceptibility to Fas-mediated apoptosis in mouse splenic B cells. In the present study, we have investigated the regulation of Fas expression and Fas-triggered apoptotis in mouse peritoneal B-1 cells. B-1 cells expressed a similar level of CD40 as that on B-2 cells, and proliferated in response to a soluble CD40 ligand (CD40L)-CD8alpha chimeric protein, suggesting that CD40 on B-1 cells is functional. In contrast to B-2 cells, B-1 cells expressed Fas at only low levels in response to CD40L-CD8alpha alone or CD40L-CD8alpha + interleukin-4, and were resistant to Fas-mediated apoptosis following these treatments. While Fas expression could be induced in B-1 cells to a comparable level as that in B-2 cells by cross-linking CD40L-CD8alpha with an anti-CD8alpha antibody, the sensitivity to Fas-mediated apoptosis in B-1 cells was significantly reduced compared with B2 cells. These results suggest that peritoneal B-1 cells from normal mice have a lower susceptibility to Fas-mediated apoptosis and may distinguish B-1 from B-2 cells. Similarly, B-1 cells from the peritoneal cavity and spleen of autoimmune-prone NZB mice exhibited reduced susceptibility to Fas-mediated apoptosis relative to their B-2 counterparts. NZB splenic B-1 cells, however, were more susceptible to Fas-mediated apoptosis than NZB peritoneal B-1 cells. The results presented here raise the possibility that the reduced susceptibility to Fas-triggered apoptosis in B-1 cells might be an accelerating factor for the autoantibody production in NZB mice.

Animals↗
PubMed1997

Experimental hepatitis in neonatally thymectomized mice: transfer of disease and the role of T cells.

Using neonatally A/J thymectomized mice, we have produced chronic hepatitis by administration of sublethal doses of Propionibacterium acnes and lipopolysaccharide (LPS). Our goal in this unique model was to evaluate the effector cell population required to generate chronic hepatitis by transferring spleen cells or splenic subpopulations derived from donor thymectomized mice with chronic hepatitis into congenic recipient nonimmunized thymectomized or sham-thymectomized animals. Several key observations were made regarding the ability to induce and to transfer disease. First, an inflammatory liver injury in neonatally thymectomized (NTx) mice was readily generated using sublethal doses of P. acnes and LPS. Second, the lesions were persistent and associated with the production of autoantibodies to liver-specific lipoprotein and anti-nuclear antibodies. Third, these features were not found in comparably injected nonthymectomized control A/J mice. Fourth, the same liver injury was transferred to neonatally thymectomized but otherwise naive mice by the transfer of donor spleen cells from affected mice previously induced to develop experimental hepatitis. Fifth, the transfer of this liver injury could not be achieved using T-cell-depleted spleen cells. Deletion of CD4+ T cells or CD8+ T cells by sensitized spleen cells resulted in suppression of the transferred liver injury. In contrast, transfer of nylon wool adherent splenic T cells induced severe hepatitis. These data suggest that the chronic liver injury induced in NTx mice by administration of P. acnes and LPS involves a breakdown in tolerance accompanied by the appearance of autoantibodies and that nylon wool adherent CD4+ and CD8+ T cells play important roles in the modulation of liver injury.

Animals↗