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Biomedical subjects

M Kurimoto

Publications and source records attributed to M Kurimoto.

At least 235 records · Page 13Linked to original sources
PubMed1995

Functional image-guided neurosurgical simulation system using computerized three-dimensional graphics and dipole tracing.

This report describes a preoperative simulation and intraoperative localization system for use with three-dimensional functional images in intracranial surgery. The system, which produces three-dimensional functional images by superimposition of the generators of somatosensory evoked potentials derived from dipole tracing, was applied in the preoperative localization of central sulci in 12 patients with intracranial disorders. The preoperative localization of central sulci was assessed by intraoperative cortical recording of somatosensory evoked potentials in three patients. In six patients, three-dimensional computer graphics were reconstructed from magnetic resonance images and allowed visualization of the lesions through the semitransparent views of the scalp surface and the brain. The three-dimensional functional images were created by superimposing the generators of somatosensory evoked potentials on three-dimensional computer graphics. This combined technique provided preoperative data regarding the three-dimensional relationship between the sensorimotor cortex and the lesions. We also developed a three-dimensional digitizer that incorporates a mechanical arm and a laser pointer for use in integrating information obtained in the preoperative simulation into the surgical field. Intraoperative localization can be performed in real time on the three-dimensional computer graphics in combination with the functional images created from dipole tracing. This system was applied in five patients who underwent surgical brain tumor resections with minimal damage to the normal brain tissue. The use of this system for stereotactic craniotomy increased the safety of the surgery by affording preoperative simulation and intraoperative localization with the three-dimensional functional images. Two illustrative case reports are presented.

Brain Diseases↗
PubMed1995

Purification and properties of a novel enzyme, maltooligosyl trehalose synthase, from Arthrobacter sp. Q36.

Arthrobacter sp. Q36 produces a novel enzyme, maltooligosyl trehalose synthase, which catalyzes the conversion of maltooligosaccharide into the non-reducing saccharide, maltooligosyl trehalose (alpha-maltooligosyl alpha-D-glucoside) by intramolecular transglycosylation. The enzyme was purified from a cell-free extract to an electrophoretically homogeneous state by successive column chromatography on Sepabeads FP-DA13, DEAE-Sephadex A-50, Ultrogel AcA44, and Butyl-Toyopearl 650M. The enzyme was specific for maltooligosaccharides except maltose, and catalyzed the conversion to form maltooligosyl trehalose. The Km of the enzyme for maltotetraose, maltopentaose, maltohexaose, and maltoheptaose were 22.9 mM, 8.7 mM, 1.4 mM, and 0.9 mM, respectively. The enzyme had a molecular mass of 81,000 by SDS-polyacrylamide gel electrophoresis and a pI of 4.1 by gel isoelectrofocusing. The N-terminal and C-terminal amino acids of the enzyme were methionine and serine, respectively. The enzyme showed the highest activity at pH 7.0 and 40 degrees C, and was stable from pH 6.0 to 9.5 and up to 40 degrees C. The enzyme activity was inhibited by Hg2+ and Cu2+.

Amino Acid Sequence↗
PubMed1995

Purification and characterization of a novel enzyme, maltooligosyl trehalose trehalohydrolase, from Arthrobacter sp. Q36.

A novel enzyme, maltooligosyl trehalose trehalohydrolase from Arthrobacter sp. Q36 was purified from a cell-free extract to an electrophoretically pure state by successive column chromatography on Sepabeads FP-DA13, Butyl-Toyopearl 650M, DEAE-Toyopearl 650S, and Toyopearl HW-55S. The enzyme specifically catalyzed the hydrolysis of the alpha-1,4-glucosidic linkage that bound the maltooligosyl and trehalose moieties of maltooligosyl trehalose. The Km of the enzyme for maltosyl trehalose, maltotriosyl trehalose, maltotetraosyl trehalose, and maltopentaosyl trehalose was 5.5 mM, 4.6 mM, 7.0 mM, and 4.2 mM, respectively. The enzyme had a molecular mass of 62,000 by SDS-polyacrylamide gel electrophoresis and a pI of 4.1 by gel isoelectrofocusing. The N-terminal amino acid of the enzyme was threonine. The enzyme showed the highest activity at pH 6.5 and 45 degrees C, and was stable from pH 5.0 to 10.0 and up to 45 degrees C. The activity was inhibited by Hg2+, Cu2+, Fe2+, and Zn2+.

Amino Acid Sequence↗
PubMed1995

Antiproliferative effect of multiple autocrine loop blockade in human malignant glioma cell lines.

The effects of specific antibodies against growth factors and receptors on deoxyribonucleic acid (DNA) synthesis in two established human glioma cell lines, A172 and TM-1, were examined. Anti-platelet-derived growth factor (PDGF), anti-basic fibroblast growth factor (bFGF), and anti-epidermal growth factor receptor (EGF-R) antibodies inhibited thymidine incorporation by both cell lines in serum-free medium. Antibody specific to transforming growth factor-alpha only slightly suppressed DNA synthesis by both cell lines. Although the antiproliferative effects of anti-PDGF and anti-bFGF antibodies decreased in serum-supplemented medium, the effect of anti-EGF-R antibody was little changed. The combination of anti-PDGF, anti-bFGF, and anti-EGF-R antibodies significantly inhibited thymidine incorporation by the two cell lines even in serum-supplemented medium. This preliminary study suggests that simultaneous blockade of multiple autocrine loops may provide a new approach to the treatment of human malignant gliomas.

Antibodies, Monoclonal↗
PubMed1995

Natural human interferon-alpha enhances the expression of intracellular adhesion molecule-1, integrin alpha 2 and beta 1 by a mucosal epithelial cell line.

We have found that pretreatment of a human oral mucosal epithelial cell line KB with natural human interferon-alpha (IFN-alpha) augments the expression of intercellular adhesion molecule-1 (ICAM-1), and the complex of CD29 and CD49b, which is known as very late antigen (VLA)-2, in a dose-dependent manner, whereas the expression of other adhesion molecules such as CD44 leukocyte function associated antigen-3 (LFA-3), VLA-4 and endothelial leukocyte adhesion molecule-1 (ELAM-1) did not show any significant changes under the same conditions. The pretreatment of KB cells with IFN-alpha also induces the adhesion of these cells to the human leukemia T cell line MOLT-16 and to peripheral T lymphocytes in a dose-dependent manner. However, the adhesion of the above-mentioned T cells to KB cells was not inhibited by specific antibodies against ICAM-1, CD29, and CD49b. The results thus show that adhesion molecules other than ICAM-1, CD29, AND CD49b are responsible for the induced adhesion between T cells and IFN-alpha-pretreated KB cells.

Antigens, CD↗
PubMed1994

Molecular cloning of the second major allergen, Cry j II, from Japanese cedar pollen.

Cloning of a cDNA from Cry j II, the second major allergen from Japanese cedar (Cryptomeria japonica) pollen, is described. An isolated Cry j II cDNA contained an open reading frame coding for 514 amino acid residues. The mature Cry j II protein consisted of 388 amino acid residues (R46-S433). According to a homology analysis, no amino acid sequence homology was observed between Cry j II and Cry j I, another major allergen. But Cry j II showed homology with polygalacturonase (PG) derived from tomato (40% identity) at the amino acid level. The sequence information can potentially be used to devise an effective course of immunotherapy for Japanese cedar pollinosis.

Allergens↗
PubMed1994

A high-level and regulatable production system for recombinant glycoproteins using a human interferon-alpha promoter-based expression vector.

A novel expression vector for human cells, pIFP, which expresses a cloned gene under the control of the human interferon-alpha-encoding gene (IFN-alpha) promoter (pIFN) was constructed. As a model of glycoprotein production, a human erythropoietin-encoding cDNA (EPO) inserted downstream from pIFN in pIFP was introduced into human B-cell leukemia-derived BALL-1 cells, and EPO-producing cells were established. Upon stimulation with Sendai virus, the cells produced human EPO at high levels. The highest production level and the highest inducibility were 872 IU/ml and 67-fold, respectively. Simultaneously, the transformed cells also produced IFN-alpha and tumor necrosis factor-alpha (TNF-alpha), as the parental BALL-1 cells did. Comparing the amounts of the substances produced, activity of the exogenous pIFN introduced seemed much higher than that of the endogenous one. Further, the transformed cells could be obtained in a large quantity by being applied to the 'in vivo cell proliferation method (hamster method)'. Human EPO produced by the transformed cells had a molecular mass range of 35 to 42 kDa, similar to that of EPO produced by CHO cells. The processing of EPO seemed to occur properly. The combination of the human pIFN, BALL-1 cells and the hamster method provides us with a useful production system for bioactive glycoproteins of human origin.

Animals↗
PubMed1994

TM-1 cells from an established human malignant glioma cell line produce PDGF, TGF-alpha, and TGF-beta which cooperatively play a stimulatory role for an autocrine growth promotion.

We have previously established a human malignant glioma cell line, TM-1. TM-1 cells could proliferate in the serum-free medium. In the present study, immunochemical analysis demonstrated that platelet-derived growth factor (PDGF), transforming growth factor (TGF)-alpha, and TGF-beta are present in the serum-free medium conditioned by growing TM-1 cells. While the cells appeared to possess a single type of binding sites for epidermal growth factor (EGF) with properties comparable to those determined for other tumor cells, the conditioned medium did not contain EGF.PDGF, TGF-alpha, and EGF added exogenously to serum-free media stimulated thymidine incorporation into DNA of TM-1 cells. In addition, antibodies specific for PDGF and TGF-alpha suppressed this activity. These results indicate autocrine and stimulatory roles of PDGF and TGF-alpha for the proliferation of TM-1 cells. As observed for other tumor cells, TGF-beta by itself weakly suppressed thymidine incorporation by TM-1 cells. However, TGF-beta employed in combination with TGF-alpha or EGF appeared to stimulate thymidine incorporation, suggesting that a cooperative action of TGF-beta with different growth factors may be involved in the stimulatory growth regulation at least for TM-1 cells.

Cell Division↗
PubMed1994

Platelet-activating factor and antiphospholipid antibodies in subarachnoid haemorrhage.

The purpose of this study was to measure plasma platelet-activating factor (PAF) concentration, PAF-acetylhydrolase activities, anti-phospholipid antibody (aPLs) titers, and platelet function in patients with subarachnoid haemorrhage (SAH) and to assess the association of these variables with the development of cerebral vasospasm. Thirty-two patients with SAH due to ruptured cerebral aneurysm were studied. Plasma PAF concentration, PAF-acetylhydrolase activity, platelet count and aggregability, and plasma factor 4 (PF4) concentrations were measured regularly until approximately 2 weeks after SAH. aPLs, including lupus anticoagulant and anti-cardiolipin IgG and IgM were measured within 3 days after SAH. Plasma PAF concentration in patients with SAH showed the highest value on the occasion during 5 to 9 days after SAH. The concentrations were higher in patients with infarction due to vasospasm than in patients without cerebral infarction on any occasions after SAH. Plasma PAF-acetylhydrolase activities did not change in patients, regardless of the presence of cerebral infarction after SAH. Increased platelet consumption and aggregability and higher concentrations of PF 4 were detected in patients with cerebral infarction and not in patients without cerebral infarction. The patients with cerebral infarction due to cerebral vasospasm had aPLs more frequently than the control volunteers. Our findings indicate that increased plasma PAF and aPLs may contribute to the pathogenesis of cerebral vasospasm after SAH.

Adult↗
PubMed1994

Effects of interferon-alpha on a reduced release of interleukin-8 from latently HIV-1-infected monocytic cell line U937 cells.

The effects of human interferon-alpha (IFN-alpha) on the release of an antimicrobial interleukin, interleukin-8 (IL-8), from human immunodeficiency virus type 1 (HIV-1)-infected myelomonocytic cell line, U937, were studied in vitro to evaluate the potential of IFN-alpha in the management of acquired immunodeficiency syndrome (AIDS)-associated opportunistic diseases. The latently HIV-1-infected U937 cells (U937/HIV-1(L)) showed a marked reduction of IL-8 secretion as compared to uninfected U937 cells, whereas IL-8 release from productively HIV-1-infected U937 cells was comparable to uninfected cells. The IFN-alpha recovered partially the reduced IL-8 level from U937/HIV-1(L) cells in a dose-dependent manner. Any significant inhibition of IFN-alpha-augmented IL-8 secrement by anti-IL-1 antibody was not observed, suggesting that the enhanced IL-8 secretion occurred without augmenting IL-1 production. The IFN-alpha-augmented IL-8 secretion from latently HIV-1-infected U937 cells may suggest a beneficial potential of IFN-alpha in a treatment of bacterial or fungal infection frequently seen in patients with progressive stages of HIV-1 infection.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Prevalence of IgE antibody to crude and purified allergens of Japanese cedar pollen among different troops of Japanese monkeys (Macaca fuscata).

We measured specific IgE antibodies to the crude allergen as well as two purified allergens (Cry j I and Cry j II) of Japanese cedar (Cryptomeria japonica--CJ) pollen in the serum of 276 Japanese monkeys in nine troops. Of 45 monkeys with CJ specific IgE in eight of nine troops, 23 (51%) were found to have IgE to both Cry j I and Cry j II, 21 (47%) only to Cry j I, and one (2.2%) only to Cry j II. The positive rate of specific IgE antibody to each allergen varied among the troops.

Allergens↗
PubMed1994

[Protracted (lasting) presence of Japanese cedar pollen allergen (Cry j I) in house dust].

We investigated the relationship between the amounts of Cry j I in house dust and airborne Cryptomeria japonica pollen in the same location. Cry j I was still detected in house dust collected two weeks after airborne C. japonica pollen had disappeared. Disappearance of Cry j I in house dust coincided with the disappearance of symptoms in the C. japonica pollinosis patients who lived in the same area. Airborne Cupressaceae pollen appeared during the latter half of the C. japonica pollen season. Disappearance of Cupressaceae pollen did not coincided with the disappearance of the symptoms in C. japonica pollinosis patients. Therefore, some symptoms of C. japonica pollinosis patients after C. japonica pollen disappeared from the air may be caused by pollen which had attached to clothes and been brought indoors.

Air Pollution, Indoor↗
PubMed1994

[Enzyme-linked immunosorbent assay for the quantification of Cry j I and Cry j II].

Enzyme-linked immunosorbent assays (ELISA) were developed to specifically quantify the two major allergens from Japanese cedar pollen, Cry j I and Cry j II. Polystyrene microplates coated with antibodies specific for Cry j I or Cry j II were incubated with an allergen and then with biotinylated anti-Cry j I or Cry j II antibody. The bound allergen-biotin Ab complexes were detected with HRPO-conjugated streptavidin and an enzyme substrate. The working ranges of Cry j I ELISA and Cry j II ELISA were 0.3-20 ng/ml and 0.6-20 ng/ml, respectively. Intra- and inter-assay coefficients of variation for reproducibility were 1.5-10.3% and 0.9-12.9%. These ELISA systems showed no cross-reactivity between Cry j I and Cry j II and showed little cross-reactivity with pollen allergens of plants botanically related to the Japanese cedar. Using the Cry j I ELISA and the Cry j II ELISA, it was possible to quantify Cry j I and Cry j II easily and accurately. These ELISA systems will be useful in various fields, especially for the analysis and standardization of the allergens necessary for diagnosis and treatment of Japanese cedar pollinosis.

Allergens↗
PubMed1993

Effects of natural interferon alpha, natural tumor necrosis factor alpha and their combination on human mesothelioma xenografts in nude mice.

Effects of human natural interferon alpha (nIFN) alone, human natural tumor necrosis factor alpha (nTNF) alone and their combination (OH-1) were tested on three human mesothelioma lines implanted in nude mice. Tumors were transplanted subcutaneously by trocar on treatment day -12. nIFN was given intraperitoneally (i.p.) at a dose of 2 x 10(7) or 2 x 10(8) IU kg-1 day-1, 5 days a week for 3 weeks. nTNF was given i.p. at a dose of 2 x 10(7) or 2 x 10(8) U kg-1 day-1 in the same schedule as that of nIFN. Tumor diameters were serially measured and tumor volumes were calculated. Antitumor effects were assessed by two methods: comparison of final tumor volumes in treated and control groups (T/C), and changes in median average total tumor volume. The treatment produced no clinically discernible toxicities. nIFN had strong inhibitory activity against all three human mesothelioma lines. nTNF alone had modest activity only at the high dose used. The combination of the two produced activity essentially similar to that produced by nIFN alone. High-dose nIFN may have a role as an active agent in the treatment of patients with mesothelioma.

Animals↗
PubMed1993

Epitopes on Cry j I and Cry j II for the human IgE antibodies cross-reactive between Cupressus sempervirens and Cryptomeria japonica pollen.

Forty sea from French patients allergic to Cupressus sempervirens pollen were tested for cross-reactivities against Cry j I, Cry j II (major allergens of Cryptomeria japonica pollen) and other pollen allergens from botanically related plants. Seventy-three per cent of the sera reacted with either Cry j I or Cry j II, or with both of them. These IgE cross-reactions were blocked effectively by mAb 046 (anti-Cry j I) or N26, T27 (anti-Cry j II), and weakly by mAbs 052, 027 and 026 (anti-Cry j I). Furthermore, the IgE antibodies in two sera, #40 and #11, bound to peptide fractions obtained from enzyme-digested Cry j I, and mAb 027 could also bind to the fractions. Analyses of the amino acid sequences of the peptides revealed that reactive peptides contained "NGNATPQLTKNAGVLTCSLSKR" sequence and the third residue N3 was glycosylated, however, when the N3 was not glycosylated, the IgE antibodies did not react, but mAb 027 could. The glycosylation of the N3 might be required for IgE-binding to the peptides. Sugar component on the N3 residue was found to be 0.4 mol galactose, 1.3 mol mannose, 0.8 mol fucose and 2.0 mol N-acetyl-glucosamine. Cross-reactivities against other pollen allergens from botanically related plants were found in most of the sera. However, many of these reactivities were detected by sandwich ELISA but not by an ELISA using allergen-coated plates, indicating that it is important to select an appropriate ELISA procedure in order to detect an allergen or an IgE antibody to an allergen.

Allergens↗
PubMed1993

Analyses of mixed melanogenesis in tyrosinase cDNA-transfected human amelanotic melanoma cells.

In the pigment cell the synthesis of tyrosinase and the formation of premelanosomes are independent, yet coordinated, processes. However, the interrelationship between the two processes has not been elucidated previously. In this study, an expression plasmid for human tyrosinase cDNA was constructed and transfected into a human amelanotic melanoma cell line, G-361. Stable transfected cells (G-CMHT-3) were obtained with high tyrosinase activity and distinct melanization occurred. As for the type of melanin, both pheo- and eumelanin contents increased in G-CMHT-3 cells. Interestingly, catalase activity as one of the other melanogenic enzymes was decreased in G-CMHT-3 cells. The decrease of catalase activity was considered to play a role in melanin-polymer formation, resulting in the increase of both pheo- and eumelanin contents. Under electron microscopic observation, dopa-oxidase-positive Golgi-associated endoplasmic reticulum of lysosome, coated vesicles, and premelanosomes were observed in pigmented G-CMHT-3 cells, and the expressed tyrosinase was considered to be well translocated to these organelles. In addition, the number of premelanosomes (stages I-III) as well as melanosomes (stage IV) increased in G-CMHT-3 cells compared to those in G-361 cells. It is also noted that G-CMHT-3 cells showed more normal phenotype premelanosomes with occasional transitional premelanosomes exhibiting partial melanin polymer formation within their concentric whorl-like internal membranes. Furthermore, the number of eumelanosomes in G-CMHT-3 cells was much larger than that in G-361 cells. These results suggest that the tyrosinase introduced by its cDNA transfection induced active and structurally non-aberrant premelanosome formation resulting in the upregulated pheo- and eumelanogenesis.

Humans↗