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I Shimada

Publications and source records attributed to I Shimada.

At least 19 recordsLinked to original sources
PubMed1998

NMR study of the interaction between the B domain of staphylococcal protein A and the Fc portion of immunoglobulin G.

The solution structure of the B domain of staphylococcal protein A (FB) complexed with the Fc fragment of immunoglobulin G (IgG) is reported. A previous NMR analysis has shown that in solution FB is composed of a bundle of three alpha-helices, helix I, helix II, and helix III [Gouda, H., Torigoe, H., Saito, A., Sato, M., Arata, Y., and Shimada, I. (1992) Biochemistry 31, 9665-9672]. In contrast, the crystal structure of FB in the FB-Fc complex lacks helix III. Uniformly 15N- and 15N/13C-labeled FB were prepared, and the backbone 13C resonances were assigned. The spectral data obtained in the present study indicated that in solution all three helices including helix III are preserved in the FB-Fc complex. The mode of interaction of FB with the Fc fragment was discussed on the basis of the combined data of hydrogen-deuterium exchange experiments and 1H-15N correlation spectroscopy. It was concluded that a contiguous surface shaped by F14, Y15, E16, L18, and H19 in helix I, and N29, Q33, L35, and K36 in helix II is responsible for the binding.

Amino Acid Sequence↗
PubMed1998

Transition protein 1 from boar late spermatid nuclei having DNA-melting activity is a dimeric protein.

Polyacrylamide gel electrophoretic behavior of boar transition protein 1, TP1, under dissociating and non-dissociating buffer conditions, and titration of fluorescently labeled TP1 with increasing amounts of TP1 showed that TP1 formed a dimer without intermolecular disulfide bond. TP1 dimer with intermolecular disulfide bond had similar DNA-melting activity to TP1, but was not detected in extracts from boar late spermatid nuclei. These results suggest that TP1 dimer without intermolecular disulfide bond induces local destabilization of DNA in the late spermatid nuclei.

Animals↗
PubMed1998

Specificities and rates of binding of anti-(6-4) photoproduct antibody fragments to synthetic thymine photoproducts.

Pyrimidine (6-4) pyrimidone photoproducts are some of the major DNA photolesions induced by ultraviolet (UV) light. A monoclonal antibody (64M5) specific to a (6-4) photoproduct has been established and the corresponding single-chain antibody (64M5scFv) has been prepared. In this study, we characterized the ligand selectivities of 64M5 and 64M5scFv using synthetic octadeoxynucleotides containing either a central cis-syn cyclobutane thymine dimer (T[c,s]T), the (6-4) photoproduct of TpT (T[6-4]T), or its Dewar isomer (T[Dewar]T) by means of enzyme-linked immunosorbent assays (ELISA). Both 64M5 and 64M5scFv recognized T[6-4]T, but not the other photoproducts. We synthesized several biotinylated oligonucleotides of different lengths containing (T[6-4]T) to analyze the effects of the antigen size on the binding rates of an antigen binding fragment (64M5Fab) and 64M5scFv by means of surface plasmon resonance. The association rate constants for oligonucleotides of different sizes containing T[6-4]T as to 64M5Fab were found to be almost the same (1.9-5.6 x 10(5) M(-1) x s(-1)), while the dissociation rate constant for the largest oligonucleotide (d8mer, 8.0 x 10(-5) s(-1)) was significantly smaller than that for the d2mer (4.2 x 10(-2) s(-1)). These results indicate that 64M5Fab recognized the d2mer as the epitope and that the binding affinity for T[6-4]T depended on the flanking oligonucleotides. The dissociation rate constants for 64M5scFv as to the antigen analogs were almost the same as those for the various T[6-4]T-oligonucleotides as to 64M5Fab, suggesting that the conformations of these antibody binding regions are pretty similar to each other.

Antibody Specificity↗
PubMed1998

Ultrastructural evidence for the formation of amyloid fibrils within cardiomyocytes in isolated atrial amyloid.

Isolated atrial amyloid (IAA) frequently affects elderly human hearts in which only the atria are involved by the deposits. Biochemical analysis has indicated that the major subunit protein of IAA is alpha-human atrial natriuretic peptide (alpha-ANP), which is synthesized by the atrial muscle cells. To define the exact location of the formation of IAA fibrils, right atria from 25 patients undergoing cardiac surgery have been examined by an immunohistochemistry and immunoelectron microscopy with anti-alpha-ANP, apolipoprotein E, amyloid P component, transthyretin, and cathepsin B antisera. Of 25 patients, 19 were involved with IAA deposits which reacted with anti-alpha-ANP, apolipoprotein E, amyloid P component antisera but not with anti-transthyretin antiserum. In 8 of them, amyloid fibrils were seen not only in the interstitium of the atrial myocardium but also in the dilated transverse tubules of the cardiomyocytes. In some cardiomyocytes, amyloid fibrils were also demonstrated within the organelles such as coated and uncoated secretory vesicles or lysosomes. These findings lead to the inescapable conclusion that the polymerization of amyloid fibrils in IAA occurs within the cytoplasm of cardiomyocytes under some conditions.

Adult↗
PubMed1997

Structural characterization of mouse monoclonal antibody 13-1 against a porphyrin derivative: identification of a disulfide bond in CDR-H3 of Mab 13-1.

The amino acid sequence of a mouse monoclonal antibody Mab13-1, a catalytic antibody against TCPP (meso-tetrakis(4-carboxyphenyl)porphyrin), was confirmed by mass spectrometric (MS) peptide mapping. The amino-terminal sequence of the heavy chain was established by MS/MS analysis of the isolated N-terminal peptide. The presence of a unique disulfide bond between Cys93H and Cys102H was identified by MS peptide mapping and sequence analysis of an S-S containing peptide. Positions of other disulfide bonds were identified to be conserved. The non-conserved disulfide bridge was found to be resistant as other intra-chain disulfide bonds against reduction under non-denaturing condition, and to be buried inside the molecule. This extra disulfide bond is expected to support antigen-binding by restricting the flexibility of CDR-H3 loop, and it might be favorable for the recognition of a plane antigen, a porphyrin derivative.

Amino Acid Sequence↗
PubMed1997

NMR analysis of the interaction between protein L and Ig light chains.

Protein L is a cell wall protein expressed by some strains of the anaerobic bacterial species Peptostreptococcus magnus. It binds to immunoglobulin (Ig) light chains predominantly of the kappa subtype from a wide range of animal species. This binding is mediated by five highly homologous repeats designated as B1-B5, each of which comprises 72 to 76 amino acid residues. The fold of the Ig light chain-binding B1 domain of protein L has previously been shown to comprise an alpha-helix packed against a four-stranded beta-sheet. The Ig-binding region of the protein L domain involves most of the residues in the second beta-strand, the C-terminal residues of the alpha-helix, and residues in the loop connecting the alpha-helix with the third beta-strand. In the present study, we have identified the protein L-binding site of an Ig light chain by use of stable isotope-assisted NMR spectroscopy. The light chain of a murine monoclonal anti-17alpha-hydroxy-progesterone Fab fragment (IgG2b, kappa) was selectively labeled with 13C at carbonyl groups of Ala, Arg, Cys, Ile, Lys, Met, Phe, Trp, or Tyr. The residues in which the carbonyl 13C chemical shift was significantly perturbed upon binding of the protein L B1 domain were preferentially found in the second beta-strand of the variable kappa domain and parts of its flanking beta-strands. None of these residues were affected by the addition of the antigen against which the monoclonal Fab fragment is directed. Therefore, we conclude that protein L binds to the outer surface of the framework region of the V(L) domain, primarily involving the V(L) second strand, and that this binding is independent of antigen-binding. The present NMR data, in combination with sequence comparisons between kappa light chains with and without protein L affinity, suggest that the amino acid substitutions at positions 9, 20, and/or 74 of the kappa light chains could crucially affect the interaction between protein L and the V(L) domain.

17-alpha-Hydroxyprogesterone↗
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

Homicide patterns in the Toyama Prefecture, Japan.

Homicides occurring in the Toyama prefecture, Japan, during the past 10 years were reviewed. Between 1985 and 1994, 56 offenders committed 63 homicides. The mean death rate for homicide was 0.55 per 100,000. The ratio of male to female victims was 1:1, while 82% of the assailants were male and 18% were female. The victim and the assailant had a close family relationship in 58.7% of the cases. Dyadic death (homicide followed by suicide) accounted for 27% of all victims. Twenty-nine per cent of the victims were murdered by mentally unstable offenders, and in almost half (44%) of the cases the offender was convicted. Homicides during robbery were rare (only two cases), and there was only one homicide during sexual assault. Death was caused by blunt instrument injury in 38.1% of cases, asphyxia in 31.7%, stabbing in 17.5%, burns in 9.5% and shooting in 3.2% (only two cases). The majority (80%) of homicides occurred at the residence of the victim(s). None of the victims had a history of drug abuse. Social conditions in Toyama prefecture, and their possible relevance to local homicide patterns, are discussed briefly.

Adolescent↗
PubMed1997

[Emergent operation after percutaneous transluminal coronary rotational atherectomy (ROTABLATOR)].

Emergent operations were performed in seven patients after percutaneous transluminal coronary rotational atherectomy (PTCRA). The causes of the emergent operations were coronary rupture in three patients, acute coronary occlusion in two patients, perforation of the ascending aorta in one patient and impossible weaning from IABP in one patient. IABP was used preoperatively in all patients. Coronary artery bypass grafting was performed in all patients. Ruptured sites of the coronary arteries were closed and perforated site of the ascending aorta was repaired. Two patients died due to cardiac failure but five patients were recovered. Coronary artery rupture was main complication after PTCRA. It is important to recognize the difference between the complication after PTCRA and that after conventional PTCA.

Adult↗
PubMed1996

The carbohydrate moiety of the bermuda grass antigen BG60. New oligosaccharides of plant origin.

BG60 is an important allergen of Bermuda grass (Cynodon dactylon) pollen, which causes allergic responses in human. It was suggested that its carbohydrate moiety may be relevant to allergic reaction (Su, S. N., Lau, G. X., Shu, P., Yang, S. Y., Huang, S. W., and Lee, Y. C. (1996) J. Allergy Clin. Immunol., in press). Therefore, the structure of the carbohydrate moiety in BG60 was investigated. The N-linked oligosaccharides were released from the glycopeptides of BG60 by digesting with a glycoamidase from sweet almond and reductively aminated with a fluorescent reagent, 2-aminopyridine. The mixture of pyridylaminated oligosaccharides were separated by high-performance liquid chromatography (HPLC) using an octadecylsilyl (ODS) column. Five oligosaccharide fractions were isolated, and each fraction was found to be homogeneous by HPLC on an amide-silica column. The structure of each of the oligosaccharides was analyzed by the two-dimensional mapping technique (Tomiya, N., Awaya, J., Kurono, M., Endo, S., Arata, Y., and Takahashi, N. (1988) Anal. Biochem. 171, 73-90), in tandem with sequential exoglycosidase digestion. The two most abundant oligosaccharides, A and B, have an unusual structural feature, i.e. the presence of an L-Fuc alpha-(1,3)-linked to Asn-linked GlcNAc without a Xyl beta-(1,2)-linked to the branching Man (see below). To the best of our knowledge, these are the first such oligosaccharides found in plant glycoproteins.

Allergens↗
PubMed1996

Expression of taste reception response of fleshfly in Xenopus oocytes.

Functional expression of the gustatory sensitivity to amino acids and sugars was investigated in Xenopus oocytes injected with poly(A+) RNA extracted from fleshfly labellar taste organs. The current induced by the application of amino acids and sugars that stimulate fleshfly sugar receptor cells was recorded under voltage clamp conditions. L-Phenylalanine and L-valine induced a large transient inward current in poly(A+) RNA-injected oocytes but only small responses in uninjected control oocytes. Glucose and fructose also produced inward currents in the RNA-injected oocytes. N-methylated compounds or D-isomers of these amino acids induced either no response or a much smaller response than L-amino acids as they did in the fleshfly sugar receptor cells. The oocyte expression system is a useful tool for characterizing the taste transduction mechanism.

Animals↗
PubMed1996

Purification and characterization of N-beta-alanyl-5-S-glutathionyl-3,4-dihydroxyphenylalanine, a novel antibacterial substance of Sarcophaga peregrina (flesh fly).

We purified a novel antibacterial substance from immunized adult Sarcophaga and determined its molecular structure to be N-beta-alanyl-5-S-glutathionyl-3,4-dihydroxyphenylalanine (5-S-GAD). We synthesized 5-S-GAD enzymatically from N-beta-alanyl-3, 4-dihydroxyphenylalanine (beta-Ala-Dopa) and reduced glutathione (GSH). The antibacterial activity of 5-S-GAD was found to be due to its production of H2O2. This is a novel antibacterial mechanism as it differs from the mechanisms of known antibacterial peptides. Two possible roles of 5-S-GAD in insect immunity, suppression of bacterial growth and activation of a Rel family transcription factor, are proposed.

Animals↗
PubMed1996

Folding topologies of human interleukin-6 and its mutants as studied by NMR spectroscopy.

To understand the structure-function relationship in the human interleukin-6 (IL-6) system, comparative studies were performed on the basis of NMR data obtained using the wild-type IL-6 and six mutants. In each of the six mutants, either Leu152, Leu159, Leu166, Leu168, Leu175, or Leu182, which exist in the C-terminal receptor-binding region, was substituted with Val. The resonance assignments of Val, Ile, Leu, and Phe residues were made by using specific double-labeling and site-specific mutagenesis strategies. On the basis of chemical shift and NOE data collected for six IL-6 mutants and those for the wild-type IL-6, we analyzed the structural changes induced by the substitution of each of the six Leu residues. The NMR data showed that substitution of Leu182 with Val (L182V) induced no structural change in IL-6, suggesting that Leu182 is located on the surface of the IL-6 molecule. A significant decrease in receptor-binding activity was observed in the L182V mutant. It was concluded that the side chain of Leu182 is directly involved in receptor binding. Substitution of Leu175 with Val (L175V) was shown to induce a significant structural change in IL-6. The NMR data are discussed on the basis of the location of four helix elements and an up-up-down-down helix topology of the predicted structure of IL-6 [Bazan, J.F. (1991) Neuron 7, 197-208]. It is possible that helix D bent more sharply toward helix B in the L175V mutant than in the wild-type IL-6 to maintain a closely packed and solvent-inaccessible core formed in the mutated region. It is suggested that the kink of helix D is related to the decrease in receptor-binding activity in the L175V mutant. On the basis of the observed NOE network, the folding topology of IL-6 was analyzed. A comparison of the folding topology of IL-6 with that of human granulocyte colony-stimulating factor determined by X-ray crystallography [Hill, C. P., Osslund, T. D., & Eisenberg, D. (1993) Proc. Natl. Acad. Sci. U.S.A. 90, 5167-5171] indicated that IL-6 has a significant similarity of folding topology to that of human granulocyte colony-stimulating factor.

Amino Acid Sequence↗
PubMed1996

Pathologic aspects of polytetrafluoroethylene sutures in human heart.

BACKGROUND: Polytetrafluoroethylene (PTFE) sutures have been widely used as a mitral chord substitute. We present the cases of 4 patients who underwent mitral valve repair with chordal replacement by PTFE sutures and these required another operation. This gave us the chance to examine the PTFE sutures. METHODS: Structural analysis of the PTFE sutures was performed 26 to 378 days postoperatively. The specimens were examined grossly, microscopically, and by scanning or transmission electron microscopy or both. RESULTS: The PTFE suture in 1 patient was found to be completely covered with endothelial cells 154 days postoperatively. There was no calcification, and the flexibility and pliability of the PTFE sutures was preserved. Even though the PTFE sutures seemed uncovered on visual inspection, there was a thin lining of collagen and fibrin on the surface. Endothelial cells were seen in areas that looked clear in one specimen 26 days postoperatively. CONCLUSIONS: We think that the new layer of collagen could be promising in terms of durability and that the endothelial layer wil resemble normal tissue in its anticoagulant properties.

Female↗
PubMed1996

Decrease in Ca2+ sensitivity as a mechanism of hydrogen peroxide-induced relaxation of rabbit aorta.

OBJECTIVE: In vascular strips, hydrogen peroxide (H2O2) relaxes alpha 1-adrenergic agonist-induced but not high-K(+)-induced contractions. The aim of this study was to explore H2O2-induced changes in [Ca2+]i of vascular smooth muscle and to elucidate the mechanisms of action of H2O2. METHODS: Isolated rabbit aortic strips were isometrically contracted with high-K+ (64.7 mM) or phenylephrine (PE, 0.3 microM). The effects of 300 microM H2O2 on [Ca2+]i of endothelium-denuded vascular smooth muscle and tension were determined simultaneously by the fura-2 method. Changes in [Ca2+]i were expressed as percentages of high-K(+)-induced values measured at the beginning of the experiments. In another series of experiments, the relaxant effect of 300 microM H2O2 was examined in high-K+ (20 mM)-induced contraction in the presence of the protein kinase C activator, phorbol 12,13-dibutyrate (PDBu). RESULTS: Hydrogen peroxide caused a reversible rise in [Ca2+]i of vascular smooth muscle under both resting conditions and in the precontracted state. During high-K(+)-induced contraction, H2O2 further increased [Ca2+]i by 26.6(s.e.m. 1.7)% accompanied by a small increase in tension of 6.5(1.9)% of high-K(+)-induced tension. By contrast, during PE-induced contraction, although H2O2 caused a comparable additional increase in [Ca2+]i (26.4(4.7)%), muscle tension fell by 28.9(2.2)% of the steady-state PE-induced tension. Hydrogen peroxide had a relaxant effect on augmented high-K(+)-induced contraction in which Ca2+ sensitivity of the contractile apparatus was elevated by PDBu. CONCLUSIONS: In spite of its effect of increasing [Ca2+]i of vascular smooth muscle, hydrogen peroxide causes relaxation of endothelium-denuded, PE-precontracted rabbit aorta. The mechanism is probably through suppression of agonist-induced augmentation of Ca2+ sensitivity of the contractile apparatus.

Animals↗
PubMed1996

[Report on the accuracy and the reliability of dip sticks].

Urinary examination with dip sticks is essential for clinical screening test and primary health care. Recently Japanese Society of Clinical Pathology has stressed the clinical use of dip sticks. Many dip sticks are available in Japan. However, few attempts have been done for external quality control of dip sticks. It is well known that there are considerable differences in the accuracy, sensitivity and stability of dip sticks. Makers are at variance in indicating concentration levels in accordance with the given color charts. Some urine chemistry analyzers for dip sticks have been developed. There was a few cases of simultaneous study on dip sticks from various makers. We, four technologists have attempted external quality control of eleven dip sticks for protein, glucose and occult blood with the same lot number (one was only for glucose) using the four different pooled urine samples and two artificial urine samples. Based on the results of this study, the following proposal to improve the accuracy and reliability of dip sticks was derived. 1) Users should have a plenty of knowledge on the difference of the quality of dip sticks of each makers. 2) Makers of dip sticks should clarify to users the method of examination, standard materials and errors. 3) Users should perform internal quality control using different pooled urine samples or different artificial urine samples on a daily basis before going with the routine work.

Glycosuria↗