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Biomedical subjects

K Kojima

Publications and source records attributed to K Kojima.

At least 19 recordsLinked to original sources
PubMed1992

Carbohydrate-binding proteins in bovine kidney have consensus amino acid sequences of annexin family proteins.

Ca(2+)-dependent carbohydrate-binding proteins were purified from bovine kidney extracts. Upon SDS-polyacrylamide gel electrophoresis under nonreducing conditions, the purified fraction gave doublet protein bands corresponding to 33 kDa (p33) and 41 kDa (p41). Under reducing conditions, a single protein band (p33) was observed. p33 and p41 were submitted to proteolytic digestion with endoproteinase Lys-C, the peptides produced were separated by reversed-phase high performance liquid chromatography, and their amino acid sequences were determined by an automated gas-phase protein sequenator. Most of the resulting partial amino acid sequences of these proteins were strikingly homologous to annexin IV, an annexin family protein, i.e. Ca2+/phospholipid-binding proteins, especially in the consensus sequences. In the presence of Ca2+, both proteins bound to vesicles composed of phosphatidylserine and phosphatidylethanolamine, but not phosphatidylcholine. These results indicated that p33 and p41 are members of annexin family proteins.

Amino Acid Sequence↗
PubMed1992

Efficient purification of a full length and biochemically active p110Rb, the retinoblastoma gene product.

Rb protein was purified from recombinant baculovirus-infected Sf9 cells to apparent homogeneity by a simple solubilization and by immunoaffinity column chromatography. It was mainly obtained as p110Rb, the underphosphorylated form of the Rb protein family. This p110Rb was shown to form a specific complex in vitro with SV40 Tag and to bind to double or single stranded DNA. It could also affect Tag helicase activity in a biphasic-dose dependent manner, due to these two biochemical functions. This purification procedure provides sufficient amounts of native Rb protein to further elucidate its role as an anti-oncogene protein and a negative regulator of the cell cycle.

Animals↗
PubMed1992

[MR imaging of thymoma--comparison with CT, operative, and pathological findings].

Twenty-six patients with thymoma, who had magnetic resonance (MR) imaging and computed tomography (CT) before surgery, were studied. Twenty-six thymomas were classified into 11 non-invasive thymomas (Masaoka's clinical stage I) and 15 invasive thymomas (stage II, III, and IV). On MR imaging compared with histological findings, low signal intensity rim of the tumor was corresponded to fibrous capsule of the tumor, and linear and/or reticular low signal intensity lines in the tumor were corresponded to the fibrous septae dividing thymoma into lobules. The detectability of these findings by MR imaging was superior to that by CT. Margin of the tumor was smooth in non-invasive thymoma rather than invasive thymoma. The diagnostic accuracy of invasion to vessel, and pleura or lung on MR imaging and CT was compared with operative and histological findings. MR imaging was same as CT in its ability to detect tumoral invasion to vessel, and slightly superior to pleura or lung. In conclusion MR images clearly show the findings corresponding to pathologic specimens, and MR imaging combining with CT is useful to differentiate non-invasive thymoma to invasive thymoma.

Adult↗
PubMed1992

Improved affinity chromatographic purification of D-mannose-N-acetyl-D-glucosamine-specific lectin from the bark of Sophora japonica eliminating the loss by sugar specific self-aggregation.

A novel D-mannose-N-acetyl-D-glucosamine-specific lectin of Sophora japonica bark, B-SJA-II, which showed self-aggregation based on sugar specificity, was purified by affinity chromatography on maltamyl-Sepharose subsequent to chromatographic separation on lactamyl-Sepharose to remove a major D-galactose-N-acetyl-D-galactosamine specific lectin, B-SJA-I. However, the yield of this method was low as a result of the sugar-specific precipitation and binding to other glycoproteins. A modified method was developed to circumvent this problem. All the purification procedures, except for the final chromatographic separation, were carried out in the presence of the haptenic sugar and the sugar-specific adsorption of B-SJA-II onto the adsorbent was carried out in a dialysis bag by gradually removing the sugar. This method gave a yield eight times higher than the original method.

Acetylation↗
PubMed1992

Affinity purification and affinity characterization of carbohydrate-binding proteins in bovine kidney.

Ca(2+)-dependent carbohydrate-binding proteins were purified from bovine kidney by two-step affinity chromatography on fetuin and heparin columns and subsequent anion-exchange high-performance liquid chromatography. On sodium dodecyl sulphate-polyacrylamide gel electrophoresis, the purified fraction gave two protein bands corresponding to proteins of relative molecular mass 33,000 (p33) and 41,000 (p41), respectively. Although the proteins had no haemogglutinating activities towards human and rabbit erythrocytes, their carbohydrate-binding activity was examined by a newly developed method using horseradish peroxidase (HRP) and/or biotin-labelled glycoconjugates as affinity probes. They could bind in a Ca(2+)-dependent manner to labelled fetuin and heparin in a specific and dose-dependent manner by solid-phase assay after immobilization on plastic plate surface. Inhibition assay of the binding revealed that N-acetylneuraminic acid is the most potent inhibitor of the proteins among the monosaccharides tested. Fucoidin and heparan sulphate most strongly inhibited the binding of the proteins to labelled heparin. Direct binding assay to acidic glycolipids prepared from bovine kidney showed that the proteins react with the ganglioside fraction but not with sulphatide [Gal(3-SO4) beta 1-1Cer]. These results indicated that the purified proteins have a significant affinity to charged oligosaccharides linking to glycoproteins, glycolipids and charged polysaccharides in a Ca(2+)-dependent manner.

Amino Acids↗
PubMed1992

[Prediction for effectiveness of steroid pulse therapy by MRI in Graves' ophthalmopathy].

Fifteen patients with Graves' ophthalmopathy (GO) were treated with intravenous methylprednisolone (steroid pulse therapy, 1g daily for 3 days a week, 2-4 times) and followed up by ophthalmological assessment and magnetic resonance imaging (MRI). The signal intensity of enlarged eye muscle and retrobulbar fat was examined with MRI at 0.5T with short inversion time inversion recovery (STIR) sequences. The signal intensity of eye muscle and retrobulbar fat tissue in STIR was evaluated as the ratio to cerebral substantia alba (signal intensity ratio). The thickness of enlarged eye muscle was measured by T1-weighted coronal images. The signal intensity ratios of enlarged eye muscle of GO patients were significantly higher than those of eight normal subjects. Although the signal intensity ratios of muscle and retrobulbar fat before therapy were not related to the severity of clinical findings of GO assessed by ophthalmopathy index, the initial signal intensity ratios of eye muscle and retrobulbar fat of ten patients with improved clinical findings of GO after steroid pulse therapy tended to be higher than those of five patients without improvement by the therapy. After the therapy the signal intensity ratios of muscle and retrobulbar fat were significantly decreased in ten patients with favorable response. Our data suggested that high signal intensity in STIR may reflect edema caused by acute inflammation associated with GO. In conclusion, MRI may be a useful tool for determining the indication and prognosis of steroid pulse therapy. We strongly recommend measuring the signal intensity of eye muscle as well as muscle thickness in MRI to evaluate the activity of GO.

Adipose Tissue↗
PubMed1992

Structure of the pine (Pinus thunbergii) chlorophyll a/b-binding protein gene expressed in the absence of light.

A gene for chlorophyll a/b-binding protein (cab) of pine (Pinus thumbergii) was isolated and sequenced. The gene (cab-6) contains an intron at a position equivalent to the type II cab genes of angiosperms. Transcript mapping analyses show that the amount of the mRNA in the dark is about half of that in the light. The cab-6 gene is expressed in dark-grown seedlings at a very high level, differing from angiosperm cab genes which are induced by light. The cab-6 gene typifies the coniferous plant cab genes in light-independent gene expression.

Amino Acid Sequence↗
PubMed1992

Relapsing acute disseminated encephalomyelitis associated with chronic Epstein-Barr virus infection: MRI findings.

A 25-year-old women had a fever, left cervical lymphadenopathy, neurological symptoms and signs, CSF pleocytosis and persistent high serum antibodies to the Epstein-Barr virus (EBV); she had a recurrence 1 year later. She was thought to have relapsing acute disseminated encephalomyelitis associated with chronic EBV infection. MRI revealed abnormalities, mainly in the right basal ganglia and left midbrain. At the time of the recurrence, further abnormalities appeared in the opposite basal ganglia and right cerebral white matter.

Adult↗
PubMed1992

Successful treatment of neonatal aneurysmal dilatation of the vein of Galen: the role of prenatal diagnosis and trans-arterial embolization.

We report a neonate with aneurysmal dilatation of the vein of Galen diagnosed prenatally by color Doppler sonography and MRI at 37 weeks' gestation. The child was treated by transarterial embolization of micro-coils 2 and 8 days after birth. The aneurysmal dilatation of the vein of Galen markedly decreased after embolization and the patient is developing normally at 2 years 5 months of age. Prenatal diagnosis and early intervention by transarterial embolization produced in a good outcome in this patient.

Adult↗
PubMed1992

Ion-spray mass spectrometric analysis of glycosaminoglycan oligosaccharides.

Oligosaccharides from hyaluronic acid and chondroitin 6-sulfate were prepared by digestion with testicular hyaluronidase and separated according to their degree of polymerization by gel-permeation chromatography. These materials were successively analyzed by negative-mode ion-spray mass spectrometry with an atmospheric-pressure ion source. An ion-spray interface was used to produce ions via the ion evaporation process, producing mass spectra containing a series of molecular species carrying multiple charges. Using two adjacent multiply charged molecular ions, the exact molecular weights up to the tetradecasaccharide were calculated with a precision of +/- 1 dalton. This type of mass spectrometry was also demonstrated to be feasible for the analysis of mixtures of oligosaccharides, including tetra-, hexa-, octa- and decasaccharides, from hyaluronic acid or chondroitin 6-sulfate without separation. Ion-spray mass spectrometry was thus shown to be applicable to the structural analysis of oligosaccharides from glycosaminoglycans.

Animals↗
PubMed1992

Substitution of p- and o-hydroxyphenyl radicals at the 8 position of purine nucleosides by reaction with mutagenic p- and o-diazoquinones.

Incubation of 2'-deoxyadenosine (dAdo), 2'-deoxyguanosine (dGuo), adenosine, guanosine (Guo), thymidine, deoxycytidine with p- and o-diazoquinones, mutagens produced by the reaction of phenol and nitrite, at pH 7 and 37 degrees C resulted in a decrease of each nucleoside depending upon the concentration of the diazoquinones. pD-dAdo, pD-dGuo and pD-Guo were isolated from the reaction mixtures of dAdo, dGuo and Guo, respectively, with p-diazoquinone at pH 9.5, and oD-dGuo was from the mixture of dGuo and o-diazoquinone at pH 9.5. The products were identified as 8-(p-hydroxyphenyl)- and 8-(o-hydroxyphenyl)-purine nucleosides by 1H- and 13C-nuclear magnetic resonance spectra, secondary ion mass spectrum, ultraviolet absorption spectrum and elemental analysis. p- and o-Diazoquinones may be converted into p- and o-hydroxyphenyl radicals, respectively, which in turn attack the 8 position of the purine nucleosides. The mutagenicity of these diazoquinones may be partly due to the radical reactions.

Adenosine↗
PubMed1992

DNA strand breakage by hydroxyphenyl radicals generated from mutagenic diazoquinone compounds.

The mutagenic diazoquinone compounds p-diazoquinone (p-DQ), o-diazoquinone (o-DQ) and 3-diazo-N-nitrosobamethan (D-BM) cleaved the phosphodiester bond of lambda DNA, phi X174 RFI DNA and M13mp8ss DNA. p-DQ also cleaved the phosphodiester bond of bis(p-nitrophenyl)phosphate. The breakage of the phosphodiester bond was inhibited by the antioxidant butyl hydroxyanisole (BHA), ethanol, the spin trapping agent DMPO, cysteine and 2-mercaptoethanol. While incubation of p-DQ and o-DQ alone gave p-hydroquinone and catechol, respectively, incubation of these compounds in the presence of BHA and ethanol gave phenol in large yields. Incubation of p-DQ and o-DQ with the spin trapping agents DMPO and PBN gave spin adducts assignable as p- and o-hydroxyphenyl adducts, respectively. The breakage of the phosphodiester bond of DNA by the diazoquinone compounds is suggested to be due to the hydroxyphenyl radicals generated during incubation.

Bacteriophages↗
PubMed1992

The efficacy of MR imaging in subdural empyema.

MRI findings of a 14-year-old boy with subdural empyema (SE) are reported and compared with those of serial CT-scan. He was admitted with fever, headache, right hemiplegia and facial palsy. Initial enhanced CT-scan revealed a slit left lateral ventricle and a shift in the mid-line structures, but failed to detect any SE. MRI at 10 days after admission clearly demonstrated SE as an area of low intensity on T1-weight (T1WI) and very high intensity on T2-weight (T2WI). Post-contrast enhanced MRI (CE-MRI), using Gd-DTPA, showed a contrast enhancement in the wall of SE. However, no definite parenchymal abnormal intensity areas were detected, suggesting that the diagnosis was made sufficiently early for timely treatment and good neurological outcome. CE-MRI proved to be a more powerful and better diagnostic procedure than enhanced CT-scan, and was very useful in determining the state and development of the disease.

Adolescent↗
PubMed1992

Role of magnetic resonance imaging in thyroid-associated ophthalmopathy: its predictive value for therapeutic outcome of immunosuppressive therapy.

To investigate the efficacy of magnetic resonance imaging (MRI) in the assessment of thyroid-associated ophthalmopathy (TAO), 51 patients with TAO were evaluated by ophthalmologic examinations and MRI at 0.5 T. Thickness of extraocular muscles (EM) was measured by T1-weighted image. Signal intensities of EM and orbital connective tissue (OCT) were measured by short inversion time inversion recovery (STIR) image and expressed as a ratio by comparison to the signal intensity of cerebral substantia alba (SI, signal intensity ratio). Significant enlargement of one or more EM was observed in 86% of patients with TAO, and SI of EM (2.15 +/- 0.63, mean +/- SD) was significantly increased compared with control values (n = 16; 1.35 +/- 0.33; t test, p < 0.01). SI of OCT tended to be greater than that in the control group, although the difference was not significant. There was a significant positive correlation between thickness of EM and severity of ophthalmopathy, assessed as an ophthalmopathy index (p < 0.05). SI of neither EM nor OCT correlated with the severity of the eye disease. To investigate whether MRI findings could predict the outcome of methylprednisolone pulse therapy, we studied 23 patients with TAO who received this treatment. SI of EM and OCT in the 12 patients giving favorable responses were significantly greater than those in the 11 patients without good response (t test, p < 0.01). On the other hand, the thickness of eye muscles did not correlate with the outcome of treatment except for that of medial rectus muscle. There was a significant correlation between SI of EM and that of OCT (r = 0.78, p < 0.01), suggesting possible similar pathologic processes in these tissues in TAO.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Existence of phosphoinositide-specific phospholipase C in rat liver nuclei and its change during liver regeneration.

We found phosphoinositide-specific phospholipase C (PtdIns-PLC) activity in nuclei isolated from rat liver. The enzyme hydrolyzed phosphatidylinositol, phosphatidylinositol 4-monophosphate (PIP) and phosphatidylinositol 4,5-bisphosphate in a Ca(2+)-dependent manner, and produced inositol mono-, bis-, and triphosphate, respectively. Neither phosphatidylcholine, phosphatidylethanolamine, nor phosphatidylserine was utilized as a substrate. After partial hepatectomy, the PtdIns-PLC activity in isolated nuclei increased transiently in the S phase (20-22 h post-hepatectomy), to 2.5-fold higher than in the control, when measured with PIP. This result suggests a close relationship between the nuclear PtdIns-PLC, especially its PIP-hydrolyzing activity, and cell proliferation.

Animals↗
PubMed1992

Inhibitory effects of triphosphate derivatives of oxetanocin G and related compounds on eukaryotic and viral DNA polymerases and human immunodeficiency virus reverse transcriptase.

In order to clarify the biological activities of (-)-oxetanocin G, and (-)-oxetanocin A and its carbocyclic analogue, (-)-carboxetanocin G, the inhibitory effects of triphosphate derivatives of these compounds (OXT-GTP, OXT-ATP, and C-OXT-GTP) on eukaryotic and viral DNA polymerases were examined. DNA polymerase alpha purified from calf thymus was weakly inhibited by OXT-GTP and OXT-ATP but strongly by C-OXT-GTP, the Ki value being 0.22 microM. On the other hand, rat DNA polymerase beta was not affected by these analogues. DNA polymerase gamma purified from bovine testes was very weakly inhibited by OXT-GTP and OXT-ATP, but not by C-OXT-GTP. DNA polymerase from herpes simplex virus type-II (HSV-II) was strongly inhibited by all three analogues, the Ki values ranging from 0.5 to 1.0 microM. Human immunodeficiency virus-encoded reverse transcriptase (HIV RT) was also strongly inhibited by these three analogues, the Ki value of C-OXT-GTP being slightly smaller than that of OXT-GTP or OXT-ATP. Analysis of products synthesized on singly primed M13 single-stranded DNA by DNA polymerase alpha, HSV-II DNA polymerase or HIV RT in the presence of the analogues revealed that OXT-GTP and C-OXT-GTP were incorporated into DNA and caused chain termination mainly at sites one or two nucleotides beyond the cytosine bases on the template.

Adenine↗
PubMed1992

Flow cytometric analysis on perforin induction in peripheral blood mononuclear cells with interleukin-2 or OK-432.

Perforin is a protein present in the cytoplasmic granules of killer cells and is considered to be an important effector molecule. We assessed the perforin appearance via flow cytometry in human peripheral blood mononuclear cells stimulated in vitro for 3 days by recombinant interleukin-2 (rIL-2) or OK-432, a biological response modifier. The relationship between the lymphocyte subsets and perforin was investigated via two-color assay. CD4-positive cells had almost no perforin, and most of the CD16-positive cells did. Regarding the relationship with CD8, some of the bright positive cells (which were likely T cells) and most of the dull positive cells (likely NK cells) had perforin. Mean fluorescence was greatest in perforin-positive cells incubated with rIL-2, less in cells incubated with OK-432, and minimal in cells incubated in a medium without additives. Immunohistochemical staining with antiperforin antibody revealed that blast-transformed and enlarge cells were stained positively and that the intensity of staining of each cell alone was enhanced in cells incubated with OK-432 or rIL-2. If the fluorescence intensity of perforin-positive cells correlates with the amount of perforin in those cells, then the appearance of perforin was enhanced with OK-432, more enhanced with rIL-2, and consistent for cytotoxicity against K562 and Daudi cells. IL-2 was induced by OK-432, suggesting that the indirect effect of this IL-2 may play a role in OK-432-perforin induction. The results suggest that perforin may be an effector molecule in killer cells induced by rIL-2 or OK-432.

Cytotoxicity, Immunologic↗