Search PubMed⌕ Search

Biomedical subjects

M Kurimoto

Publications and source records attributed to M Kurimoto.

At least 217 records · Page 12Linked to original sources
PubMed1996

Purification and characterization of thermostable maltooligosyl trehalose trehalohydrolase from the thermoacidophilic archaebacterium Sulfolobus acidocaldarius.

A thermostable maltooligosyl trehalose trehalohydrolase from the thermoacidophilic archaebacterium Sulfolobus acidocaldarius ATCC 33909 was purified from a cell-free extract to an electrophoretically pure state by successive column chromatographies on Sepabeads FP-DA13, Butyl-Toyopearl 650M, DEAE-Toyopearl 650S, Toyopearl HW-55S and Ultrogel AcA44. The enzyme had a molecular mass of 59,000 by SDS-polyacrylamide gel electrophoresis and a pI of 6.1 by gel isoelectrofocusing. The N-terminal amino acid of the enzyme was methionine. The enzyme showed the highest activity from pH 5.5 to 6.0 and at 75 degrees C, and was stable from pH 5.5 to 9.5 and up to 85 degrees C. The activity was inhibited by Hg2+, Cu2+, Fe2+, Pb2+, and Zn2+. The Km values of the enzyme for maltosyl trehalose, maltotriosyl trehalose, maltotetraosyl trehalose, and maltopentaosyl trehalose were 16.7 mM, 2.7 mM, 3.7 mM, and 4.9 mM, respectively.

Chemical Phenomena↗
PubMed1996

Purification and properties of a novel enzyme, trehalose synthase, from Pimelobacter sp. R48.

A novel enzyme, trehalose synthase, was purified from a cell-free extract of Pimelobacter sp. R48 to an electrophoretically homogeneous state by successive chromatographies on DEAE-Toyopearl 650, Butyl-Toyopearl 650, and Mono Q HR5/5 columns. The molecular weight of the enzyme was estimated to be 62,000 by SDS-polyacrylamide gel electrophoresis, and the enzyme had a pI of 4.6 by gel isoelectrofocusing. The enzyme catalyzed the conversion of maltose into trehalose by intramolecular transglucosylation. The enzyme also converted into maltose but was inactive on other saccharides. The N-terminal amino acid of the enzyme was serine. The optimum pH and temperature were pH7.5 and 20 degrees C, respectively. The enzyme was stable in the range of pH 6.0-9.0 and up to 30 degrees C for 60 min. The rate of conversion of maltose into trehalose was independent of the maltose concentration. The maximum yield of trehalose from maltose were 81.8%, 80.9%, and 76.7% at 5, 15, and 25 degrees C, respectively. The activity was inhibited by Cu2+, Hg2+, Ni2+, Zn2+, and Tris.

Amino Acid Sequence↗
PubMed1996

Cloning and sequencing of trehalose biosynthesis genes from Rhizobium sp. M-11.

The two genes encoding maltooligosyl trehalose synthase and maltooligosyl trehalose trehalohydrolase, which are related to biosynthesis of alpha, alpha-trehalose, were cloned from Rhizobium sp. M-11. Sequence analysis showed that the synthase gene composed of 2316 bp was connected with the hydrolase gene of 1788 bp by an overlap of one nucleotide. The deduced amino acid sequences of both enzymes have several regions common to amylolytic enzymes belonging to an "alpha-amylase family".

Amino Acid Sequence↗
PubMed1996

Extradural optic nerve decompression for fibrous dysplasia with a favorable visual outcome.

A 10-year-old boy with progressive left visual disturbance associated with craniobasal fibrous dysplasia underwent left frontotemporal craniotomy. Dysplastic lesions of the sphenoid ridge, orbital roof, anterior clinoid, and ethmoid sinus were removed through an extradural pterional approach and the optic nerve was completely decompressed. His vision was markedly improved postoperatively. Consecutive follow-up studies for 3 years have shown no deterioration of his visual acuity. Early optic nerve decompression is highly recommended to preserve visual function in patients with craniofacial fibrous dysplasia causing visual disturbance.

Child↗
PubMed1996

Elevated plasma basic fibroblast growth factor in brain tumor patients.

We attempted to determine whether the plasma concentration of basic fibroblast growth factor (bFGF) was elevated in brain tumor patients. The plasma concentration of bFGF was measured in 55 brain tumor patients and 17 normal subjects by enzyme immunoassay. Upper limit of plasma bFGF in the normal subjects was 1.6 pg/ml. Elevated plasma bFGF levels were observed in 28 patients including 13 of 17 glioma patients, eight of 19 benign tumor patients, and seven of 19 malignant tumor patients. Twelve of 14 malignant glioma patients had elevated plasma bFGF levels. There was a good correlation (r = 0.42, p < 0.05) between the elevated plasma bFGF level and the tumor volume. Further studies are needed to determine whether the plasma bFGF level is a clinically useful diagnostic and prognostic marker for patients with brain tumors.

Adult↗
PubMed1996

[A case of atlanto-axial rotatory fixation associated with Jefferson's fracture].

The authors present a case of atlanto-axial rotatory fixation associated with Jefferson's fracture. A 52-year-old man was admitted to our hospital complaining of severe neck pain and torticollis after a traffic accident. Cervical x-ray films showed fracture of the atlas. CT scans demonstrated traumatic subarachnoid hemorrhage and atlanto-axial rotatory fixation. The patient was managed with skull traction and reposition was achieved. Although he was maintained in a halo device for 4 months, rotary fixation recurred. He underwent posterior fusion between the atlas and axis. We review the literature and discuss the diagnostic problems and methods of treatment for atlanto-axial rotatory fixation.

Atlanto-Axial Joint↗
PubMed1995

The use of computed tomography in the prediction of delayed cerebral infarction following acute aneurysm surgery for subarachnoid haemorrhage.

In order to predict the occurrence of cerebral infarction after aneurysmal surgery in patients with subarachnoid haemorrhage, we measured the amount of subarachnoid blood on initial and on postoperative computed tomograms. We used a reliable grading method to estimate the amount of blood on computed tomograms in 24 patients with infarction due to vasospasm and 45 patients without cerebral infarction, all of whom underwent aneurysmal surgery within 48 hours after the ictus. The total amount of subarachnoid blood on admission and on the day after operation was more in the cerebral infarction group than in the non-infarction group. The clearance rate of subarachnoid blood by surgery was lower in patients with cerebral infarction than in patients without infarction and the predominant site of subarachnoid blood corresponded with the site of the infarct. Of 24 patients with cerebral infarction, 22 (92%) belonged to the group whose initial total blood score was more than 10 on admission and whose clearance rate by surgery was less than 50%. Therefore, we propose this range to be an indication for the occurrence of cerebral infarction in postoperative patients due to cerebral vasospasm. The presence of intracerebral haematoma and the amount of ventricular blood and their clearance by surgery were also estimated for the prediction of delayed cerebral infarction after aneurysmal surgery. However, they had no relation to the occurrence of cerebral infarction due to vasospasm.

Adult↗
PubMed1995

Plasma platelet-derived growth factor-B chain is elevated in patients with extensively large brain tumour.

The plasma concentration of the platelet-derived growth factor (PDGF)-B chain and the plasma platelet factor 4 (PF4) levels were measured in 17 healthy controls and 55 brain tumour patients. In the 17 normal controls, the plasma PDGF-B and PF4 levels were 523 +/- 157 pg/ml (mean +/- SD) and 84 +/- 37 ng/ml, respectively. In the brain tumour patients, these values were 881 +/- 854 pg/ml and 93 +/- 64 ng/ml, respectively. The plasma PDGF-B concentration was elevated above the upper limit of normal individuals in 12 (22%) of the 55 patients. However, since the corresponding PF4 levels suggested the platelet activation, the increased plasma PDGF-B may have originated from platelets. To address this, platelet releasing experiments were performed on citrated blood samples from 5 normal individuals. The plasma PDGF-B and PF4 levels from the 17 normal controls and those observed in the platelet releasing experiments correlated with a regression line of Y = 240 + 4.86X (Y:PDGF, X:PF4). There were only 6 (11%) patients whose plasma PDGF-B level was elevated above the 95% confidence limit estimated from the corresponding PF4 value. In these patients, the tumour volumes were extensively large, and those elevated PDGF-B values decreased after treatment and became elevated again in three patients with recurrent glioblastoma. Although the plasma tumour-derived PDGF-B was detected only in an extensively large brain tumour, it might be a useful plasma marker evaluating the effects of therapy and prognosis in such patients.

Adolescent↗
PubMed1995

Anti-phospholipid antibodies and cerebral vasospasm following subarachnoid haemorrhage.

Delayed ischaemic deficits due to cerebral vasospasm contribute to the high morbidity and mortality rates associated with subarachnoid haemorrhage. We evaluated the usefulness of measuring anti-phospholipid antibodies (aPLs) for prediction of the occurrence of symptomatic vasospasm and the outcome after subarachnoid haemorrhage. 32 consecutive patients with subarachnoid haemorrhage due to ruptured cerebral aneurysms were studied. They were admitted and operated on within 72 hours after the onset of subarachnoid haemorrhage. aPLs such as lupus anticoagulants, anti-cardiolipin IgG and anti-cardiolipin IgM were measured repeatedly after admission. Furthermore, platelet count, platelet aggregability and plasma platelet factor 4 were also measured. Eleven among the 32 patients (34.4%) showed positive in the examination for aPLs. Although aPLs could not predict symptomatic vasospasm, once symptomatic vasospasm occurred, patients with aPLs frequently demonstrated cerebral infarction and therefore their outcome was worse. aPLs were associated with a severe initial clinical grade and SAH grade on CT scan. Therefore it may explain the association of aPLs with worse outcome. aPLs were detected between 1 and 7 days. Four of 6 patients (67%) with aPLs became negative between 7 and 13 days after subarachnoid haemorrhage. The mechanism of transient aPLs is unclear but it is more likely to occur in the severer grade patients. The reduction in platelet count, the increased platelet aggregability, and the increased plasma platelet factor 4 concentration were also observed in aPLs-positive patients with symptomatic vasospasm.

Adult↗
PubMed1995

Potential application of human interferon-alpha in microbial infections of the oral cavity.

We have been evaluating the potential use of interferon-alpha (IFN-alpha) against fungal infections of the oral cavity. IFN-alpha has been reported to enhance the antifungal activity of neutrophils. This cytokine is also known to synergize with interleukin-1 in enhancing a number of immunomodulatory responses. To study cytokine involvement in oral defense mechanisms against microbial infection, we first demonstrated the presence of antimicrobial interleukins (IL)-1 alpha, IL-1 beta, and IL-8 in the saliva, which can all augment the microbicidal activity of neutrophils, and the presence of epithelial cells and neutrophils in oral lavage fluid from healthy volunteers. Immunostaining for cytokines produced by these cells showed that the candidate producers of both IL-1 alpha and IL-8 are epithelial cells, but those of IL-1 beta remained inconclusive. We next found that IFN-alpha enhanced IL-1 alpha-augmented neutrophil-mediated anticandidal action while marginally enhancing IL-8- and IL-1 beta-mediated reactions. These results suggest that IFN-alpha is a potential agent for treating oral mycosis by cooperating with endogenous cytokine(s) in the saliva, in addition to its intrinsic antiviral action.

Adult↗
PubMed1995

Establishment of new interferon-gamma-resistant mutant cells with dominant phenotypes.

We established interferon-gamma-resistant (IGR) cells from a human colon adenocarcinoma cell line, LoVo. Their resistance was extremely high, and the ED50 values of IFN-gamma were > 10(5) IU/ml. Interestingly, although IGR-5 cells were still sensitive to the antiproliferative effect of IFN-alpha, the cells lost responsiveness to the antiviral effects of both IFN-alpha and gamma. Another clone, IGR-53, was unresponsive to both the antiproliferative and antiviral effects of either IFN-alpha or gamma. Furthermore, the IFN-gamma-resistant phenotypes of IGR cells were apparently dominant to the parental LoVo cells based on complementation tests. Although IGR-53 cells lack IFN-gamma receptors, IGR-5 cells seemed to have functional IFN-gamma receptors and processing mechanisms of IFN-gamma bound to the receptors. Northern analysis showed that IGR-5 cells responded to IFN-gamma and alpha, but the enhancement of IRF-1 expression by IFN-gamma was markedly suppressed.

Adenocarcinoma↗
PubMed1995

Natural human interferon-alpha inhibits the adhesion of a human carcinoma cell line to human vascular endothelium.

The adhesion of cells to the microvascular endothelium is an essential step in the inflammatory response and metastasis. We have found that pretreatment of a human epidermoid carcinoma cell line, KB, with natural human interferon-alpha (IFN-alpha) inhibited the binding of the malignant cells to human umbilical vein endothelial cells (HUVEC) in a dose- and time-dependent manner. As one of several possible mechanisms for this inhibition, the expression of some revelant adhesion molecules on KB cell surfaces was examined after IFN-alpha treatment. Apart from a slight increase in the expression of integrin alpha 4 beta 1 (very late activation antigen 4, VLA-4), no changes in the expression of other adhesion molecules, such as sialyl Lewis X, CD44, and leukocyte function-associated antigen 1 (LFA-1), which is known to be a heterodimer of CD11a and CD18, were observed after treatment with IFN-alpha. In addition, the cell viability of KB was not affected by treatment of the cells with IFN-alpha, although the cell proliferation was markedly inhibited, indicating that the inhibitory effect of IFN-alpha on KB cell binding to vascular endothelium is not a result of a cytotoxic effect of IFN-alpha. Because the metastatic process requires not only the adhesion of tumor cells to vascular endothelium during their extravasation but also proliferation at distant sites, our findings from this in vitro experimental model suggest that IFN-alpha may have a potential inhibitory effect on tumor cell metastasis.

Antineoplastic Agents↗
PubMed1995

Carbohydrate structures of the glycoprotein allergen Cry j I from Japanese cedar (Cryptomeria japonica) pollen.

The glycoprotein allergen Cry j I from Japanese cedar (Cryptomeria japonica) pollen was treated with pepsin and glycopeptidase A to release asparagine-linked oligosaccharides. The reducing ends of the oligosaccharides were aminated with the fluorescent reagent 2-aminopyridine. The oligosaccharide derivatives were purified by gel permeation chromatography and reversed-phase HPLC. Their structures were determined by sequential exoglycosidase digestion and 500 MHz 1H-NMR spectroscopy. Four oligosaccharide structures, A, B, C, and D, were identified as the xylose-containing complex-type. They were present at a molar ratio of 8:1:6:1. By amino acid sequence analyses of the tryptic peptides, Asn-170 and Asn-333 of Cry j I were found to carry asparagine-linked oligosaccharides. [formula: see text]

Allergens↗
PubMed1995

Metastasis-promoting activity of a novel molecule, Ag 243-5, derived from mycoplasma, and the complete nucleotide sequence.

We found that mycoplasma-infected cells have a higher ability to metastasize in vivo than non-mycoplasma-infected cells. To investigate this phenomenon, we obtained a monoclonal antibody, MAb 243-5, by immunization with Mycoplasma arginini-infected RPMI 4788 cells. This MAb recognized a mycoplasmal protein with an MW of 47 kDa and completely inhibited the experimental metastasis of M. arginini-infected RPMI 4788 cells using a nude mouse model. Using this MAb, we purified a molecule called Ag 243-5 and determined the N-terminal amino acid sequence and clarified the entire nucleotide sequence of the Ag 243-5 gene. PCR analysis showed the existence of a homologous gene in Mycoplasma hyorhinis. Four sequential injections of Ag 243-5 (30 micrograms/shot) promoted the experimental metastasis of non-mycoplasma-infected RPMI 4788 cells more than 10-fold using a nude mouse model. Ag 243-5 also promoted the experimental metastasis of the non-mycoplasma-infected mouse colon cancer cell line colon 26. This metastasis-promoting effect was neutralized by MAb 243-5.

Amino Acid Sequence↗
PubMed1995

Sensitivity to two major allergens (Cry j I and Cry j II) in patients with Japanese cedar (Cryptomeria japonica) pollinosis.

BACKGROUND: Japanese cedar (Cryptmeria japonica: CJ) pollinosis is one of the most important allergic diseases in Japan. Recently, the second major allergen (Cry j II) was isolated from CJ pollen. There have been no prevalence studies of sensitivity to Cry j I and Cry j II among a large number of patients with pollinosis. OBJECTIVE: This study was conducted to evaluate the prevalence of sensitivity to Cry j I and Cry j II. We measured specific IgE antibodies to these allergens in the sera of 145 patients. Furthermore, comparison of the sensitivity to Cry j I and Cry j II was examined by the histamine release assay. METHODS: Specific IgE antibodies to Cry j I and Cry j II were assayed by a fluorometric ELISA. Allergen-specific histamine release was measured by a radioimmunoassay kit. RESULTS: More than 90% of 145 patients had specific IgE antibodies to both allergens, the remainder had specific IgE to either one or the other. There were seasonal changes in the level of specific IgE. The changes in the levels of anti-Cry j II IgE antibodies were parallel to those of anti-Cry j I IgE. The histamine release assay with leucocytes from the patients demonstrated that the allergenic potency of the two allergens is almost the same. CONCLUSION: Cry j II is an as important a major allergen as Cry j I.

Adult↗
PubMed1995

Cry j 2, a major allergen of Japanese cedar pollen, shows polymethylgalacturonase activity.

We examined Cry j 2, a major allergen of Japanese cedar (Cryptomeria japonica) pollen, for polygalacturonase enzyme activity, since a nucleotide sequence of cDNA of Cry j 2 showed a significant homology with that of tomato polygalacturonase. Polygalacturonase is well known to depolymerize preferentially polygalacturonic acid (PGA) by hydrolysis. However, Cry j 2 did not act on PGA, but was found to depolymerize pectin and methylesterified PGA in a dose-dependent manner. The substrate specificity of Cry j 2 was different from that of polygalacturonase derived from Aspergillus niger. The depolymerizing activity of Cry j 2 reached a maximum at 50%-60% of methylesterification of PGA. In contrast, polygalacturonase showed its maximum activity of PGA, and the activity decreased as the degree of methylesterification increased. Interestingly, the pectin-depolymerizing activity of Cry j 2 was due to a hydrolysis, but not a lyase, activity which splits the glycosidic bonds by beta-elimination, since no unsaturated uronides were found by measurement of absorbance at 235 nm in the reaction mixture. The enzyme activity was markedly inhibited by anti-Cry j 2 antibodies. These results indicate that Cry j 2 probably has polymethylgalacturonase enzyme activity, as postulated by von Neukom in 1963, although existence of this activity has not yet been proven.

Allergens↗
PubMed1995

Cry j I, a major allergen of Japanese cedar pollen, has pectate lyase enzyme activity.

In the course of analyzing the partial amino acid sequences of Cry j I, a major allergen of Japanese cedar (Cryptomeria japonica) pollen, we found a peptide fragment which has a significant homology to some pectate lyase isozymes secreted by plant pathogenic bacteria. Therefore, we investigated whether Cry j I has pectate lyase activity. Cry j I reacted with polygalacturonic acid, resulting in the release of unsaturated uronide products. The optimum temperature and pH for the reaction were 60-70 degrees C and pH 10. The enzymatic reaction had an absolute Ca2+ ion requirement. These characteristics were very compatible with the character of the pectate lyase isozymes reported previously. These results clearly show that Cry j I has pectate lyase activity.

Allergens↗