Biomedical subjects
Publications and source records attributed to K Kojima.
We report a case of a cerebral aneurysm arising from the bifurcation of the left middle cerebral artery that ruptured into a left middle cranial fossa arachnoid cyst, associated with acute subdural hematoma. We discuss the relationships of aneurysm, arachnoid cyst, and subdural hematoma.
Gastric epithelial chemokine response is a primary factor in the induction of gastric inflammation associated with Helicobacter pylori infection. Because sustained inflammation is a risk for gastric mucosal damage, agents that down-regulate inflammatory responses may be of therapeutic significance. We examined the effect of polaprezinc, a potent antiulcer agent, on proinflammatory cytokine-induced interleukin (IL)-8 expression in gastric epithelial cells. Because IL-8 expression is regulated by the transcription factor nuclear factor-kappaB (NF-kappaB), we also examined the effect of polaprezinc on NF-kappaB activity. MKN28 cells were used as a model of gastric epithelial cells. Secreted IL-8 was quantified by IL-8 specific enzyme-linked immunosorbent assay, and IL-8 mRNA expression was examined by Northern blot analysis. NF-kappaB activity was analyzed by electrophoretic mobility shift assay. Western blot analysis with anti-phospho-IkappaB-alpha antibody was performed to assess IkappaB-alpha phosphorylation. Polaprezinc-suppressed IL-8 secretion induced by tumor necrosis factor alpha (TNF-alpha) or IL-1beta in a dose-dependent manner. IL-8 mRNA expression also was inhibited by polaprezinc. NF-kappaB activation in response to TNF-alpha, IL-1beta, phorbol ester, and H(2)O(2) was down-regulated by polaprezinc. Western blot analysis showed inhibition of TNF-alpha-induced IkappaB-alpha phosphorylation in the presence of polaprezinc. Collectively, these results suggest that polaprezinc is a novel type of anti-inflammatory agent that down-regulates inflammatory responses of gastric mucosal cells.
Mitochondrial processing peptidase (MPP) specifically recognizes a large variety of mitochondrial precursor proteins and cleaves off N-terminal extension peptides. The enzyme is a metalloprotease and forms a heterodimer consisting of structurally related alpha- and beta-subunits. To investigate the responsibility of MPP subunits for substrate recognition, we monitored interaction of the fluorescent-labeled peptide substrates with the MPP and its subunits. The specific binding of the peptide to the MPP was confirmed by findings of the direct participation of arginine residues in the binding, which are located at position -2 and the position distal to the cleavage site and are essential for the cleavage reaction. MPP bound the substrate peptides with high affinity only in the dimeric complex, and each subunit monomer had about a 30-fold less affinity than the complex. The individual subunit required arginines at different positions in the peptide for binding, although their affinities were much lower than that of MPP. Fluorescence quenching analysis showed that the peptide bound to MPP was buried in the enzyme. Thus, both subunits of MPP might be required for formation of a substrate binding pocket with multiple subsites lying across them.
Mitochondrial processing peptidase, a metalloendopeptidase consisting of alpha- and beta-subunits, specifically recognizes a large variety of mitochondrial precursor proteins and cleaves off N-terminal extension peptides. The enzyme requires the basic amino acid residues in the extension peptides for effective and specific cleavage. To elucidate the mechanism involved in the molecular recognition of substrate by the enzyme, several glutamates around the active site of the rat beta-subunit, which has a putative metal-binding motif, H56XXEH60, were mutated to alanines or aspartates, and effects on kinetic parameters, metal binding, and substrate binding of the enzyme were analyzed. None of mutant proteins analyzed was impaired in dimer formation with the alpha-subunit. Mutation of glutamates at positions 79, 129, and 136, in addition to an active-site glutamate at position 59, resulted in a marked decrease in cleavage efficiency. Together with sequence alignment data, glutamate 136 appears to be involved in metal binding. Glutamate 129 is mostly responsible for the catalysis, as there was a considerable decrease in kcat value by the mutation. Mutation of glutamate 79 led to decrease in kcat value and increase in Km values. Substrate binding experiments using an environmentally sensitive fluorescence probe attached to the peptide showed that the mutation caused a remarkable environmental change at the binding site to the N-terminal region of the substrate peptide and decreased binding of the peptide, thereby suggesting that glutamate 79 participates primarily in substrate binding. Thus, some glutamate residues required for substrate binding and cleavage activity have been identified.
Leber's congenital amaurosis (LCA), a type of congenital blindness, is clinically and genetically heterogeneous and often associated with systemic anomalies. We report on two sisters who were born to a consanguineous couple and had retinitis pigmentosa-like pigmented retinal lesions, alternating exotropia, bilateral cataracts, and anomalous coarse facies characterized by deformed skull with narrow forehead, low anterior hairline, hypertelorism, short philtrum, thin upper lip, and prominent jaw; cerebellar vermis hypoplasia; dilatation of the fourth ventricle; severe mental retardation; tremor; brisk deep tendon reflexes and abnormal behavior; and skeletal abnormalities such as limited extension of elbow and/ or finger joints and talipes equinovalgus. Skin defect and renal anomalies were seen in only one patient. Our patients are the first familial LCA associated with cerebellar vermis hypoplasia, and the disease involving particular multiple systemic anomalies may represent a distinct clinical entity.
We evaluated the role of obesity in proteinuria by treadmill exercising of simple obese subjects and non-obese subjects with non-insulin dependent diabetes mellitus in whom the albumin excretion rate at rest was within normal range. Non-obese healthy volunteers were studied as the controls. The fractional renal clearances of four endogenous proteins, albumin, IgG, IgG4, and beta2-microglobulin were measured before, during, and after treadmill exercise in 17 simple obese and 15 non-obese diabetic subjects, and in 21 normal subjects. Exercise increased the fractional albumin clearance in all groups. In diabetic subjects, the fractional IgG4 clearance also increased: fractional beta2-microglobulin clearance increased in normal controls and in diabetics. In obese subjects, the fractional clearances of albumin, IgG, and IgG4 were similar to those in normal controls, but fractional beta2-microglobulin clearance was significantly lower. These results suggest that enhanced microalbuminuria in obese subjects is probably of glomerular origin. In normal subjects and diabetics, exercise-induced microproteinuria is probably of both glomerular and tubular origin. Defect in the charge-selective barrier of the glomerular capillary wall has been implicated in diabetics. Thus some additional factors relevant to obesity must be taken into account in the consideration of the mechanism of microalbuminuria in diabetics with obesity.
We have previously reported a method to immobilize protein ligands on microtiter plates coated with methyl vinyl ether-maleic anhydride copolymer (MMAC) [Isosaki, K., et al. (1992) J. Chromatogr. 597, 123-128]. In this study, we improved the MMAC method to efficiently immobilize not only small ligands such as peptides and oligosaccharides, which could not be efficiently immobilized previously, but also heparin via its reducing end. Amino and hydrazino groups were introduced to MMAC-coated microtiter plate wells by coupling to acid anhydride groups of MMAC with 1,6-hexamethylenediamine and adipic acid dihydrazide, respectively. The amino groups introduced were allowed to react with peptides by use of divalent cross-linkers. Hydrazino groups were allowed to react with formyl groups of saccharides by reductive amination. Peptides and oligosaccharides were immobilized in a dose-dependent manner by these methods. In the case of the angiotensin peptide thus immobilized, the detection limit by monoclonal antibodies was as low as 0.1-1 fmol peptide per well. Application of 20-200 nmol oligosaccharides to the well was sufficient to immobilize and subsequently detect lectins. Furthermore, heparin immobilized on the hydrazinocoated wells was successfully used for the binding assay of annexin IV.
Vitronectin is a multifunctional plasma glycoprotein which may regulate the systems related to protease cascades such as the coagulation, fibrinolysis, and complement systems as well as cell adhesion. Solid-phase assays and affinity chromatography on immobilized glycolipids indicated that vitronectin purified under denaturing conditions bound to sulfatide (Gal(3-SO4)beta1-1ceramide), cholesterol 3-sulfate, and various phospholipids, but not gangliosides. Only the unfolded or multimeric form of vitronectin bound to sulfatide, suggesting a conformational dependency of the binding activity, while vitronectin bound to cholesterol 3-sulfate regardless of its conformational state. The recombinant domains of human vitronectin and mutants with certain domains deleted were separately expressed in E. coli as fusion proteins. Using the recombinants, sulfatide-, phosphatidylserine-, cholesterol 3-sulfate-, Type I collagen-, heparin-, and beta-endorphin-binding activities were found to be attributable to hemopexin domain 2 and hemopexin domain 1. The possibility was suggested that the presence of a somatomedin domain and/or connecting region flanking hemopexin domain 1 inactivated its heparin binding. De-N-glycosylation of plasma vitronectin significantly affected the cholesterol sulfate- and collagen-binding activities, although its effects were opposite. These findings suggest that diverse ligand-binding activities could be attributed to pexin family motifs but that the interdomain interactions and glycosylations modulate the ligand binding activities of vitronectin.
We have previously demonstrated that annexin IV, one of the calcium/phospholipid-binding annexin family proteins, binds to glycosaminoglycans (GAGs) in a calcium-dependent manner (Kojima, K., Yamamoto, K., Irimura, T., Osawa, T., Ogawa, H., and Matsumoto, I. (1996) J. Biol. Chem. 271, 7679-7685). In this study, we investigated the GAG binding specificities of annexins IV, V, and VI by affinity chromatography and solid phase assays. Annexin IV was found to bind in a calcium-dependent manner to all the GAG columns tested. Annexin V bound to heparin and heparan sulfate columns but not to chondroitin sulfate columns. Annexin VI was adsorbed to heparin and heparan sulfate columns in a calcium-independent manner, and to chondroitin sulfate columns in a calcium-dependent manner. An N-terminal half fragment (A6NH) and a C-terminal half fragment (A6CH) of annexin VI, each containing four units, were prepared by digestion with V8 protease and examined for GAG binding activities. A6NH bound to heparin in the presence of calcium but not to chondroitin sulfate C, whereas A6CH bound to heparin calcium-independently and to chondroitin sulfate C calcium-dependently. The results showed that annexin IV, V, and VI have different GAG binding properties. Some annexins have been reported to be detected not only in the cytoplasm but also on the cell surface or in extracellular components. The findings suggest that the some annexins function as recognition elements for GAGs in extracellular space.
Baker's asthma, a typical occupational allergic disease, is a serious problem in the food industries. In this study, purification and identification of major allergens recognized by IgEs in sera of allergic patients were performed. Major immunoreactive proteins were purified from the albumin fraction by gel filtration on a Toyopearl HW-50 column followed by reverse-phase HPLC. The N-terminal amino acid sequences and molecular masses measured by MS indicated that the major immunoreactive proteins are members of the alpha-amylase inhibitor family, 0.19 and 0.28. Significant leukotriene release by each purified protein was observed in cell-associated stimulation tests, suggesting in vivo activity of these antigens. Carbohydrate analyses of major allergens indicated that they are monoglycosylated but not N-glycosylated in spite of the presence of a potential N-glycosylation site. Recombinant 0.19 expressed in Escherichia coli showed the same reactivity with IgE as native wheat 0.19 in Western blotting and ELISA using methyl vinyl ether maleic anhydride co-polymer as an immobilizing reagent, suggesting that the allergenic epitopes are located in the peptide portions.
A treatment policy must be established for primary mediastinal seminoma. We have treated five patients with this entity during 18 years. All our patients presented with a bulky mass as is usual for this disease. Our first patient was treated surgically and then with radiation, but developed recurrences and died 11 years after the initial diagnosis. Three subsequent patients, one with multiple lymph node metastases, were treated with radiation followed by cisplatin. Our most recent patient received two courses of adriamycin-reinforced PVB, and then radiation for consolidation, followed by another course of chemotherapy. For these five patients, the 5- and 10-year survival rates were both 100%. A review of the literature emphasized the fact that either radiation or surgery has recently been replaced by chemotherapy as the front-line treatment of this rare tumor in light of a better response to the latter form of treatment. We fully agree with this policy. Based on the favorable long-term results of our patients we conclude that chemo-radiotherapy can cure primary mediastinal seminoma, even in its extended form, without surgery. An initial three courses of cisplatin-based chemotherapy like adriamycin-reinforced PVB or BEP should be followed by radiation of up to 4,000 cGy for consolidation. Surgery may play a limited role for tumors that are small at presentation, or for any possible viable residue seen on roentgenograms following chemo-radiotherapy.
We report on a 25-year-old cyanotic man who was diagnosed as having a pulmonary arteriovenous fistula. His chief complaint had been shortness of breath since childhood. Polycythemia (Hb 21.4 g/dl) was detected during a health checkup at his company. A chest X-ray showed an abnormal mass in the left lung. Blood gas analysis showed severe hypoxia with PaO2 of 38.6 mmHg at room air. Angio-CT showed a large aneurysmal lesion at S6 of the left lung with a large feeding artery and vein. Oxygen saturation was 75.2% in the radial artery and 62.5% in the right atrium. The right-to-left shunt ratio was therefore calculated as 62%. The aneurysmal lesion was resected by segmentectomy of the left S6 following division of A6 and V6. After a successful operation, the patient no longer had shortness of breath or cyanosis and blood gas analysis showed PaO2 as 84.3 mmHg at room air. Pulmonary angiography showed no residual shunt lesion.
We report a case of refractory anemia with excess of blasts in transformation with the translocation (8;21), which is frequent in acute myeloid leukemia (AML) but not in myelodysplastic syndromes (MDS). Bone marrow blasts were 1.6% and an extensive myeloid differentiation was noted. Fluorescence in situ hybridization analysis revealed the presence of 21q22 translocations in mature neutrophils, indicating that clonogenic blast progenitors could actively undergo terminal differentiation to mature end cells in vivo. We consider that t(8;21)+ MDS may represent a rare clinical manifestation of M2-AML, in which blast progenitors have an extensive differentiation potential to mature neutrophils without maturation arrests.
This report presents 46 Japanese patients with idiopathic portal hypertension (IPH) in whom non-shunt operation was performed for the management of esophageal varices. Non-shunt operation included transthoracic esophageal transection (Sugiura's procedure) in 37 patients, transabdominal esophageal transection (TAET) in 3 patients, and Hassab's procedure in 6 patients. Rates of postoperative variceal eradication were: 78.4% by Sugiura's procedure; 100% by TAET; and 50% by Hassab's procedure. The cumulative rates for recurrent varices and recurrent bleeding were 3.9%, and 5.1%, respectively, at 5 years, and 8.9% and 9.8% at both 10 and 15 years. Only 3 patients required additional endoscopic injection sclerotherapy to treat recurrent varices. Although 3 patients developed upper gastrointestinal bleeding, the source of hemorrhage was esophageal varices in 1, and portal hypertensive gastropathy in 2; none of the patients died from bleeding. Actuarial survival for all patients was 87.5% at 5 years, 77.9% at 10 years, and 58.8% at 15 years. There were no deaths within the first 30 days after surgery. These results show that non-shunt operation is useful in preventing bleeding from esophageal varices in patients with IPH.
Three new hederagenin-based acetylated saponins isolated from the fruits of Gliricidia sepium, were identified by chemical and spectroscopic methods as hederagenin-3-O- (4-O-acetyl-beta-D-xylopyranosyl)-(1-->3)-alpha-L-rhamnopyranosyl-(1-->2 ) -alpha-L-arabinopyranoside, hederagenin-3-O-(3,4-di-O-acetyl-beta-D- xylopyranosyl)-(1-->3)-alpha-L-rhamnopyranosyl-(1-->2)-alpha- arabinopyranoside and hederagenin-3-O-(3,4-di-O-acetyl-alpha-L- arabinopyranosyl)-(1-->3)-alpha-L-rhamnopyranosyl-(1-->2)-alpha-L- arabinopyranoside.
We report the youngest known case with Baló's concentric sclerosis (Baló's disease), a variant of multiple sclerosis. This 4-year-old Japanese boy was diagnosed by clinical manifestations and by characteristic findings on magnetic resonance imaging (MRI). Dexamethasone was given intravenously, 3 mg twice daily for 10 days. The clinical manifestations were resolved within 2 weeks, and the MRI findings were markedly improved after 3 weeks. Following the initiation of steroid therapy, he showed remarkable clinical and physical improvement. It cannot be excluded that the clinical improvement resulted from the steroid therapy.
The subtype of staphylococcal enterotoxin C (SEC) of 33 S. aureus clinical isolates was determined by polymerase chain reaction and direct DNA sequencing of a portion of the SEC gene encoding the SEC subtype-specific region. With the exception of a single strain with the SEC2 gene, all other strains showing different biologic and genetic properties were proved to possess the SEC3 gene.
We report a case of B-cell chronic lymphocytic leukemia (B-CLL) in which trisomy 12 and t(14;18)(q32;q21) were simultaneously detected in the same leukemic clone. Southern blot analysis showed that the BCL2/IgJH rearrangement occurred at the major breakpoint region in the hot spot of the BCL2 gene. Double color fluorescence in situ hybridization analysis using multiple probes indicated that clonal B-cell with t(14;18) represented a subpopulation of the total leukemic cells and that trisomy 12 followed t(14;18) as the cytogenetic aberration in the development of B-CLL. Our findings suggests that both the t(14;18) and the trisomy are secondary chromosomal changes in the leukemogenesis of B-CLL.