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S Iwanaga

Publications and source records attributed to S Iwanaga.

At least 109 records · Page 6Linked to original sources
PubMed1995

Changes in contractility and afterload have only slight effects on subendocardial systolic flow impediment.

To test the hypothesis that contractility did not greatly influence systolic impediment to subendocardial flow we perfused the coronary artery at 70 mmHg and altered aortic pressure in 7 dogs and contractility in another 7. We measured myocardial systolic flow impediment (SFI) by comparing regional flows while beating and during asystole. Cardiac contraction impeded 29% of subendocardial asystolic flow, which was not affected by either intervention. In subepicardium, contraction increased flow by 25%, but dobutamine impeded systolic flow. Subepicardial SFI was only 16% of subendocardial SFI. Dobutamine slightly decreased estimated percent systolic myocardial blood flow (%SMBF) in subendocardium (+/- 12%) but decreased subepicardial %SMBF (45.5 to 17.4%). Phasic coronary flow pulsatility increased more with dobutamine than increased afterload, and pulsatility and SFI correlated only in subepicardium. Systolic-to-total coronary flow ratio and %SMBF did not correlate closely in subendocardium. SFI was most prominent in the subendocardium, whereas subepicardial SFI mainly determined epicardial coronary flow pulsatility. We conclude that the effects of contractility changes differ when evaluating regional SFI vs. phasic flow pulsatility.

Animals↗
PubMed1995

Characterization of mitogenic substances in the hot water extracts of bupleuri radix.

Bupleuri Radix is a commonly used medicinal plant in Kampo medicine, and its hot water extracts show mitogenic activity to murine lymphocytes. In this paper the mitogenic substances in the hot water extracts of Bupleuri Radix (Bup-HWE) were fractionated and characterized physicochemically and immunologically. Most of these substances were recovered from mol. wt of more than 200 kDA fraction (fr. C-13). Separation of fr. C-13 by phenol-water fractionation method gave water soluble and phenol soluble mitogenic substances. These substances showed the activity even in C3H/HeJ mice, and polymyxin B or lysozyme treatment did not abrogate the activity, suggesting that the active substances are not related to bacterial lipopolysaccharide. Treatment of the mitogenic substances recovered from the phenol layer with NaCLO2, a polyphenol degrading chemical, significantly reduced the activity, but pronase and pectinase treatments were not effective. The mitogenic substances in the water layer were active even after NaCLO2 treatment. These findings suggested that the mitogenic substances of Bup-HWE are large molecular weight polyphenolic compounds and polysaccharide. The mitogenic substances are suggested to be B cell mitogens.

Adjuvants, Immunologic↗
PubMed1995

Increased protection of the ischemic myocardium by decreased aortic pressure.

The elevation of aortic pressure increases myocardial oxygen consumption and increases the blood supply to the myocardium. It is not obvious whether elevated systemic arterial pressure would enhance or diminish myocardial protection during acute myocardial ischemia. This report reviews previously published data on the effects of aortic pressure elevation on the coronary pressure-flow relationship, and on the ischemic myocardium in the dog. The shift of the maximally-dilated coronary pressure-flow line to the right on the pressure-flow diagram is an indication of the deterioration of the oxygen supply/demand ratio caused by aortic pressure elevation. The only maneuver recognized for protecting the ischemic myocardium is early reperfusion. In patients with de novo acute myocardial ischemia, we propose that myocardial protection can be enhanced by reduction of systemic blood pressure until coronary reperfusion therapy is initiated.

Animals↗
PubMed1995

[An analysis of factors related to recurrence of superficial bladder cancer after transurethral resection].

A total of 205 patients with primary superficial bladder cancer (Ta, T1) followed more than 3 years were retrospectively analyzed for factors related to recurrence of tumors after transurethral resection. Patients age were 25 to 90 years old, average 61 years old, and there were 160 males and 45 females. Initial tumor grades were G0 in 4 patients, G1 in 48, G2 in 134 and G3 in 19. Seventy four patients had Ta tumor and 131 had T1. Initial treatments were transurethral resection (TUR) alone in 137 patients. TUR with intravesical chemotherapy in 64, with BCG therapy in 7 and others in 7. Factors examined included age, sex, chief complaint, shape, size, and number of tumors, tumor distribution (single area or multiple area), histological grade, stage and intravesical chemotherapy. Overall non-recurrent rate were 81.7% at 1 year, 60.7% at 3 year, 53. 8% at 5 year and 44.2% at 8 year. Five-year non-recurrent rate according tumor factors, showed significant difference regarding tumor size (< 1 cm or 1 cm <: P = 0.027), tumor number (single or multiple: P = 0.004), tumor distribution (single area or multiple area: p = 0.002), histological grade (< G1 or G2 < : p = 0.001) and stage (Ta or T1: p = 0001). However, there were no significant difference regarding factors of age, sex, chief complaint, tumor figure and presence or absence of intravesical chemotherapy. This results suggested that the tumor factors of size, number, tumor distribution, grade and stage were highly related to intravesical tumor recurrence of superficial bladder cancer.

Adult↗
PubMed1995

Annexin V is localized in association with Z-line of rat cardiac myocytes.

OBJECTIVE: The aim of this study was to characterize a 33-kDa protein (p33) isolated from bovine liver and to determine the subcellular localization of the protein in rat cardiocytes as well as in non-cardiac tissues. METHODS: Cycles of calcium-induced precipitation coupled with EGTA-resolubilization were used to isolate crude annexins from bovine and rat tissues. Column chromatography was performed to purify the p33 from the crude annexins. The protein was identified as annexin V by partial amino acid sequence determination. Specificity of anti-annexin V antibody was examined by using Western blotting after one- or two-dimensional electrophoresis. For characterization of the protein, immunofluorescence microscopy and actin-binding assays were carried out. RESULTS: Immunofluorescence microscopy showed that annexin V was stained as a striated pattern along myofibrils on frozen sections of both atria and ventricles of adult rats. The striations were seen more clearly in cultured rat atrial myocytes. Examination of doubly stained cardiocytes with anti-annexin V and anti-alpha-actinin by a confocal laser scanning microscope suggests that annexin V is localized in association with the Z-line of rat cardiac myocytes. We also found that annexin V was stained intensely in actin-rich regions of non-cardiac tissues such as bile canaliculi of rat liver and brush border-terminal web region in the epithelial cells of both small intestine and kidney proximal tubular cells. F-actin binding experiments revealed that annexin V failed to bind to F-actin directly in vitro. CONCLUSION: Our results suggest that annexin V is a new component of the Z-line in rat cardiocytes and might be involved in regulation of its organization.

Actins↗
PubMed1995

Cloning and nucleotide sequence of the gene cluster encoding ribosomal proteins S12 and S7 from Mycobacterium bovis BCG.

A pair of oligonucleotide primers, based on the experimentally determined amino terminal sequence of Mycobacterium bovis BCG ribosomal protein S12 (MboS12) and a highly conserved sequence found in all mycobacterial ribosomal S12 proteins, was used for polymerase chain reaction (PCR) with M. bovis genomic DNA as template. The nucleotide sequence of the 338 bp fragment thus produced confirmed its origin in MboS12 gene. A 5.0 kb EcoRI fragment of M. bovis DNA hybridizing to this fragment was cloned. Its sequencing analysis revealed the presence of two open reading frames in the same strand. Their amino acid sequences deduced from DNA sequence showed high homology with Escherichia coli ribosomal proteins S12 and S7. However, the intercistronic region between S12 and S7 genes, which plays an important role for autoregulation for the str operon in E. coli, is completely absent in M. bovis.

Amino Acid Sequence↗
PubMed1994

Structure and biological activity of a 1,3-beta-D-glucan-binding protein in crustacean blood.

The prophenoloxidase activating system, an enzyme cascade present in arthropod blood, has been shown to be involved in defense and recognition reactions. This system is converted to its active form by fungal 1,3-beta-D-glucans through binding to a plasma protein, a 1,3-beta-D-glucan-binding protein. Here the molecular cloning and carbohydrate composition of the 1,3-beta-D-glucan-binding protein from the freshwater crayfish Pacifastacus leniusculus are reported. It is also demonstrated that this protein can act as an opsonin, stimulating phagocytic uptake of yeast particles by isolated blood cells. The deduced amino acid sequence of 1,339 residues shows no significant similarity to proteins with similar functions in other animals such as the mannan-binding and lipopolysaccharide-binding proteins present in mammals. However, a short sequence motif with similarity to the active site of microbial 1,3-1,4-beta-D-glucan 4-glucanohydrolases was found to occur twice in the 1,3-beta-D-glucan-binding protein.

Amino Acid Sequence↗
PubMed1994

Identification of regions of bovine factor VII essential for binding to tissue factor.

Initiation of the extrinsic blood coagulation pathway is mediated by a complex formed between plasma-derived factor VII/VIIa and cell-derived tissue factor (TF). To identify the site(s) of interaction, zymogen VII and VIIa were enzymatically and chemically modified, and their affinities for TF were estimated by measuring their inhibitory effects on the amidolytic activity enhanced after formation of the VIIa-TF complex. We found that the VIIa-light chain (Ki = 3.5 x 10(-7) M) and its fragment consisting of the gamma-carboxyglutamic acid (Gla)-domain and the first epidermal growth factor (EGF)-like domain (Gla-EGF1 peptide; Ki = 1.0 x 10(-6) M) have an affinity for TF. Therefore, one of the binding sites of VII with TF is probably located in the Gla-EGF1 region. On the other hand, a dansyl-Glu-Gly-Arg chloromethyl ketone-treated Gla-domainless VIIa (Ki = 0.7 x 10(-7) M) showed a high affinity for TF, whereas the corresponding Gla-domainless VII similarly treated showed no binding potential, thereby indicating that binding site(s) other than in the Gla-EGF1 region are present in VIIa but not in VII. Acetylation or carbamylation of the alpha-amino group of the NH2-terminal Ile-153 of VIIa resulted in the loss of binding affinity for TF; such modifications convert VIIa into a zymogen-like inactive form by destroying the salt bridge between Ile-153 and Asp-343 in VIIa. The rate of carbamylation of VIIa was reduced in the presence of TF. Protection of the alpha-amino group of Ile-153 from carbamylation after complex formation was consistent with salt bridge formation between Ile-153 and Asp-343 in the VIIa-TF complex. Therefore, binding of TF with the heavy chain of VIIa may induce a conformational change that brings the alpha-amino group of Ile-153 close to the beta-carboxyl group of Asp-343 to make a stable salt bridge.

1-Carboxyglutamic Acid↗
PubMed1994

Cloning and sequencing of the cDNA encoding human glutaredoxin.

Glutaredoxin (thioltransferase) is a small, heat-stable protein, which is involved in thiol/disulfide exchange reactions. We have isolated a cDNA that encodes glutaredoxin from a human brain cDNA library. The encoded protein contains 106 amino acids with a calculated molecular mass of 11.76 kDa and an isoelectric point of 8.09. The amino acid sequence deduced from the cDNA is more than 80% identical to those of other mammalian glutaredoxins.

Amino Acid Sequence↗
PubMed1994

Activation peptide of human factor IX has oligosaccharides O-glycosidically linked to threonine residues at 159 and 169.

O-Linked oligosaccharide chains were identified in the activation peptide (AP) of human blood coagulation factor IX. The peptide obtained from human factor IX was separated into three molecular species (AP alpha, AP beta, and AP gamma) by reversed-phase high-performance liquid chromatography. Amino acid analysis showed that AP alpha, but not AP beta and AP gamma, contained galactosamine in addition to glucosamine, thereby suggesting the presence of an O-linked sugar chain(s) in the molecule of AP alpha. A nonapeptide (AP alpha-D4, residues 157-165) and an undecapeptide (AP alpha-D5, 166-176) derived from AP alpha contained Thr-159 and Thr-169, neither of which could be identified using a gas-phase protein sequencer. All other serine and threonine residues present in AP alpha were identified by peptide sequencing. Component sugar and sialic acid analyses of AP alpha-D4 and AP alpha-D5 revealed that they contained 1 mol each of N-acetyl-D-galactosamine (GalNAc), D-galactose (Gal), and sialic acid. Fast atom bombardment tandem mass spectrometric analysis of AP alpha-D4 suggested the existence of Gal-GalNAc-Thr, NeuNAc-(Gal-)GalNAc-Thr, and NeuNAc-Gal-GalNAc-Thr structures. On the basis of amino acid analysis after the isolation of AP alpha, it accounted for approximately 35% of the total activation peptide obtained. From these results, it was concluded that a part of the activation peptide of human factor IX in circulating blood has tri- and tetrasaccharides O-glycosidically linked to the threonine residues at 159 and 169.

Amino Acid Sequence↗
PubMed1994

Role of hemocyte-derived granular components in invertebrate defense.

Figure 2 illustrates an outline of the cellular and humoral defense systems in limulus. On the basis of the knowledge described above, it is suggested that granular components present in L and S granules in the hemocytes play a decisive role in the biological defense for this animal. The isolated L granules contain at least three clotting factors plus coagulogen as the major component. The known anti-LPS factor and a number of additional unknown protein components are also present in the L granules. On the other hand, the isolated S granules contain antimicrobial tachyplesins as the major component, in addition to six unidentified proteins. We speculate that the L-granule-derived protein components, which probably contain all the factors essential for the Limulus clotting system participate, in immobilizing invading microbes, and that the S-granule-derived tachyplesins contribute to a self-defense system against invaders. Although we have not mentioned hemolymph plasma components, there are many humoral factors, such as proteinase inhibitors, alpha 2-macroglobulin, various lectins, C-reactive protein, and polyphemin, all of which are important for antimicrobial defense. Furthermore, Liu and colleagues have reported several endotoxin-binding proteins and a cell-adhesion protein found in the Limulus hemocytes. Although the exact functions of these substances are unknown, they may act in concert with other components to provide biological defense for the animal. Nevertheless, compared to our knowledge of mammalian blood cells, much less remains to be learned of biological/physiological events in horseshoe crab hemocytes.

Amino Acid Sequence↗
PubMed1994

Horseshoe crab (1,3)-beta-D-glucan-sensitive coagulation factor G. A serine protease zymogen heterodimer with similarities to beta-glucan-binding proteins.

Horseshoe crab factor G is an intracellular serine protease zymogen that initiates the (1,3)-beta-D-glucan-sensitive hemolymph clotting pathway. Unlike other known serine protease zymogens, which are composed of a single subunit, factor G consists of two distinct subunits, alpha and beta, which are autocatalytically converted to active factor G in the presence of (1,3)-beta-D-glucan. We have now cloned and sequenced cDNAs encoding both subunits of factor G. The subunits are derived from separate mRNA species and thus encoded by different genes. Subunit beta is a serine protease zymogen which consists of 278 residues with a calculated molecular mass of 30,846 Da; it exhibits homology to the serine protease domain of horseshoe crab factor B. Subunit alpha, on the other hand, is a new type of mosaic protein with intriguing features. The mature protein consists of 654 residues with a calculated molecular mass of 73,916 Da. The NH2-terminal portion of this subunit is similar to bacterial beta-1,3-glucanases. Its 126 amino acid COOH terminus exhibits a repetitive sequence having partial homology to xylanases. Between these regions are three repeating units of 47 amino acids, whose similarity to carbohydrate-binding proteins suggests that these may be the (1,3)-beta-D-glucan-binding domain(s) of factor G. Factor G, thus, is a structurally unique heterodimeric serine protease zymogen and as such may represent a new class of active defense proteins.

Amino Acid Sequence↗
PubMed1994

A Limulus intracellular coagulation inhibitor with characteristics of the serpin superfamily. Purification, characterization, and cDNA cloning.

A Limulus intracellular coagulation inhibitor, designated LICI, was isolated from hemocytes of the Japanese horseshoe crab (Tachypleus tridentatus), using three steps of chromatography, including dextran sulfate-Sepharose CL-6B, Sephacryl S-200, and Mono S. LICI is a single-chain glycoprotein with an apparent M(r) = 48,000 estimated by SDS-polyacrylamide gel electrophoresis. It blocks the amidolytic activities of Limulus lipopolysaccharide-sensitive serine protease, factor C, by forming a covalent 1:1 complex with the protease. The second-order rate constant for inhibition of factor C was 2.5 x 10(6) M-1 s-1 at 37 degrees C. LICI also inhibited human alpha-thrombin, rat salivary kallikrein, bovine plasmin, and trypsin but not Limulus clotting enzyme, Limulus factor B, bovine factor Xa, human factor XIa, human tissue plasminogen activator, human urokinase, chymotrypsin, elastase, and papain. Glycosaminoglycans such as heparin and heparan sulfate had no effect on the inhibitory activity. A cDNA coding for LICI was isolated from a hemocyte cDNA library. The open reading frame of the 1,257-base pair cDNA codes for the mature protein of 394 amino acids, of which 223 residues were confirmed by amino acid sequence analysis. LICI shows significant sequence identities to members of the serpin superfamily, such as human plasminogen activator inhibitor type 2 (40%) and human monocyte/neutrophil elastase inhibitor (39%). LICI contains a putative reactive site, -Arg-Ser-, at the corresponding position present in several inhibitors of the serpin superfamily. The subcellular localization, determined using an anti-LICI polyclonal antibody, indicated that LICI colocates with the Limulus serine protease zymogens in large granules in the hemocyte.

Amino Acid Sequence↗
PubMed1994

Structure-function relationships of tachyplesins and their analogues.

Haemocytes of the horseshoe crab (Limulus) contain a new family of arthropodous peptide antibiotics, termed the tachyplesin family. These cationic peptides are composed of 17-18 amino acid residues with a C-terminal arginine alpha-amide. Tachyplesin I takes on a fairly rigid conformation constrained by two disulphide bridges and adopts a conformation consisting of an antiparallel beta-sheet connected by a beta-turn. Isopeptides of tachyplesin I with amino acid replacements, tachyplesins II and III, and polyphemusins I and II have also been found in the haemocytes of the South-East Asian species and Limulus polyphemus. These peptides are present in abundance in the small granules of the haemocytes and inhibit strongly the growth of not only Gram-negative and Gram-positive bacteria but also fungi such as Candida albicans. Tachyplesin exists in the prepro form consisting of 77 residues; this precursor is probably processed by intracellular proteases and an amidation enzyme before incorporation into the small granules of the haemocytes. We examined the mode of action of tachyplesin I on biomembranes, comparing it with that of gramicidin S. Tachyplesin caused an efflux of K+ from Staphylococcus aureus and Escherichia coli cells similar to that caused by gramicidin S. Another antimicrobial substance, anti-LPS factor, has been isolated from haemocytes.

Amino Acid Sequence↗
PubMed1994

Measurement of volumetric coronary blood flow by simultaneous intravascular two-dimensional and Doppler ultrasound: validation in an animal model.

We examined the accuracy and feasibility of using simultaneous intracoronary Doppler and two-dimensional (2D) ultrasound imaging in the measurement of volumetric coronary blood flow (CBF). A femoral artery-to-circumflex coronary artery shunt was created in four dogs with tubing that incorporated an in-line transit-time ultrasound (TTU) flow probe. A 2D ultrasound catheter was introduced over a 0.014-inch Doppler guide wire into the circumflex artery with the guide wire tip positioned 2 cm beyond the imaging catheter tip. Cross-sectional area (CSA) and average peak velocity (APV) were recorded. CBF was determined from the previously validated relation CBF = CSA x 0.5 APV and the adjusted measurement formula CBF = CSA x 0.47 APV. Within the 119 measurements made, TTU CBF varied from 31 to 385 ml/min. An excellent correlation was found between 2D/Doppler-derived and TTU CBF with both constants; measurement agreement was improved and bias minimal with the 0.47 constant (slope = 0.9997; r = 0.99; p < 0.0001; SEE = -6.7 +/- 8.6). We conclude that simultaneous 2D and Doppler ultrasound yields accurate estimates of volumetric CBF.

Animals↗
PubMed1994

The localization of lipopolysaccharide in an endotoxemic rat liver and its relation to sinusoidal thrombogenesis: light and electron microscopic studies.

The distribution of lipopolysaccharide (LPS) and sequential thrombus formation in the liver was investigated by immunohistochemical and cytochemical techniques in endotoxemic rats, using horseshoe crab factor C, a specific ligand for biologically active LPS, a monoclonal antibody against it, and rabbit anti-rat fibrinogen IgG. One hour after the intravenous administration of LPS (5 mg/kg), LPS was localized in the secondary lysosomes of Kupffer cells and in the vesicles of endothelial cells, mainly at the peripheries of the hepatic lobules. Small necrotic foci of hepatic tissue were scattered close to the LPS-containing Kupffer cells, and were frequently associated with infiltration of neutrophils and deposition of fibrin. Three hours after the administration of LPS, the immunohistochemical reaction of LPS became stronger and was mostly confined to Kupffer cells. Strands of polymerized fibrin were frequently observed on both the surface of the LPS-containing Kupffer cells and on endothelial cells. These findings suggest that the activation of the coagulation cascade in plasma is first initiated, even though only transiently, by hepatic necrosis which is probably caused by LPS-activated leukocytes, and then by the procoagulant activity expressed on the surface of both Kupffer cells and endothelial cells. Fibrinogen-related antigens were also immuno-ultrastructurally detected in the lysosomes of Kupffer cells three hours after the injection of LPS, which suggested that the Kupffer cells phagocytozed and degraded fibrin. Therefore Kupffer cells in endotoxemia may closely participate in both the sinusoidal thrombogenesis and degradation of fibrin.

Animals↗
PubMed1994

D-myo-inositol 1,4,5-trisphosphate-binding proteins in rat brain membranes.

Rat brain membrane fractions obtained using Triton X-100 were applied to a D-myo-inositol 1,4,5-trisphosphate [D-Ins(1,4,5)P3] immobilized column, followed by gel filtration and anion-exchange chromatography. Two proteins with molecular masses of 130 and 85 kDa, as assessed by SDS-polyacrylamide gel electrophoresis, were purified to apparent homogeneity as D-[3H]Ins(1,4,5)P3-binding proteins with no D-Ins(1,4,5)P3-metabolizing activity. Partial amino acid sequence determinations of these proteins revealed that the 130 kDa protein appears to be a new D-Ins(1,4,5)P3-binding protein and the 85 kDa protein is a delta 1-isozyme of phospholipase C. We have previously purified 130 and 85 kDa proteins as D-[3H]Ins(1,4,5)P3-binding proteins, from rat brain cytosol fraction. Antibodies against the 130 kDa protein from the cytosol cross-reacted with the membrane 130 kDa protein purified in this study, suggesting that the membrane 130 kDa protein is likely to be the same as the protein from the cytosol fraction. The inhibition of D-[3H]Ins(1,4,5)P3 binding by D-isomers of inositol phosphates available clarified that the 130 kDa protein has a similar affinity for D-Ins(1,4,5,6)P4 to that for D-Ins(1,4,5)P3, while the 85 kDa protein is specific to D-Ins(1,4,5)P3.

Amino Acid Sequence↗