Search PubMed⌕ Search

Biomedical subjects

S Iwanaga

Publications and source records attributed to S Iwanaga.

At least 73 records · Page 4Linked to original sources
PubMed1997

Spindle cell carcinoma of the breast: a case report and an immunohistochemical study including p53 and Ki-67 expression.

A rare case of spindle cell carcinoma (SpCC) of the breast occurring in a 51-year-old Japanese woman is reported. A firm and well-circumscribed tumor, measuring 9 x 8.5 x 8.5 cm, was located on the upper lateral region of the right breast. Microscopically, the tumor consisted of sheets of both malignant spindle cells and poorly differentiated ductal carcinoma containing squamoid islands with gradual transition to the spindle cell component. The immunocytochemical expression of epithelial markers was recognized in the spindle cells, as well as in the carcinomatous cells. Moreover, the spindle cell component expressed vimentin, alpha-smooth muscle actin and S-100 protein. Ultrastructurally, in addition to the features of adenocarcinoma, squamous or myoepithelial differentiation was confirmed in the spindle cell component. These findings thus suggest an epithelial origin with squamous differentiation and myoepithelial participation in the genesis of SpCC. In a comparative study, the expression of p53 protein and Ki-67 as a proliferation marker in each component of this tumor was also investigated. The mean p53 labeling index (LI) in both the carcinomatous and spindle cell area was similar, however the mean MIB-1 LI in the spindle cell area was significantly higher than that in the carcinomatous area. The results indicate that p53 overexpression is involved in the tumorigenesis of both components in the SpCC, and the spindle cell component shows a higher degree of proliferative activity than the carcinomatous component.

Biomarkers↗
PubMed1997

Gastric carcinosarcoma (sarcomatoid carcinoma) with rhabdomyoblastic and osteoblastic differentiation.

A rare case of carcinosarcoma (sarcomatoid carcinoma) with rhabdomyoblastic and osteoblastic differentiation occurring in the gastric remnant is reported. A 69-year-old Japanese man who had undergone a partial gastrectomy for a duodenal ulcer 30 years earlier, presented with anemia, epigastralgia, and an abdominal mass. The diagnosis of gastric carcinosarcoma was made based on the findings of endoscopic biopsies. The patient was thus scheduled to undergo a surgical operation, but he died of respiratory failure. At autopsy, a huge polypoid tumor measuring 20 x 18 x 8 cm was located on the greater curvature of the gastric remnant. Microscopically, the tumor consisted of intimately mixed tubular adenocarcinoma and heterologous mesenchymal elements containing rhabdomyosarcoma and osteosarcoma. Between these components, a morphological transition from the adenocarcinoma element to the sarcomatous element was observed. Ultrastructually, rhabdomyoblastic differentiation was confirmed in the sarcomatous areas. Immunocytochemical expressions of epithelial markers including epithelial membrane antigen and cytokeratins (35bH11 and 34bE12) were recognized not only in the carcinomatous cells but also in the sarcomatous cells. These findings suggest that carcinomatous cells appear to transform into cells with sarcomatous features.

Aged↗
PubMed1997

Tissue distribution and subcellular localization of rabbit liver metalloendopeptidase.

We have previously isolated rabbit liver microsomal metalloendopeptidase (MEP) as a candidate for the processing enzyme of vitamin K-dependent plasma proteins. A cDNA coding for MEP has revealed that it is structurally related to metalloendopeptidase-24.15, which catalyzes the proteolytic processing of several bioactive peptides. In this study we examined the tissue distribution and subcellular localization of MEP by light and electron microscopic immunohistochemical methods, in addition to Northern blot analysis. Chicken polyclonal antibodies were raised by using synthetic peptides AG1 (Met31-Asn46) and AG3 (Asp537-Gly551) derived from the sequence of MEP. Both anti-AG1 and anti-AG3 antibodies reacted specifically with MEP, as judged by Western blotting and immunohistochemical methods. Both antibodies gave an identical staining distribution, which was localized on the luminal cell surfaces and in the cytoplasm of the following organs: liver, brain, lungs, kidneys, esophagus, stomach, duodenum, pancreas, placenta, epididymis, uterus, ovary, and oviduct. Northern blot analysis revealed that the expression of MEP mRNA is similar to its immunohistochemical distribution except in the heart. These results suggest that MEP may participate more closely in a degradation role in peptide metabolism in various tissues than in a processing role of the proprotein, like metalloendopeptidase-24.15.

Amino Acid Sequence↗
PubMed1997

Analysis of mitogenic substances in Bupleurum chinense by ESR spectroscopy.

The polyphenolic substance(s) in the hot water extract of Bupleurum chinense (PSF) showed strong mitogenic activity. In this paper, we analyzed PSF by using ESR spectroscopy, and found that i) PSF showed a strong ESR signal on g = 2.005 which was similar to the commercially available lignin; ii) Sho-saiko-to, which contains an extract of B. chinense, also showed similar signals on ESR; iii) Powdered B. chinense also showed similar signals on g = 2.005. Peroxidase activity, essential for producing polyphenolic substances, was detected in the cold water extract of B. chinense. In addition, the signal intensity of the ESR spectrum of B. chinense was increased after boiling. The data of the ESR spectra of the model reactions using lignin, arginine, proline and maltose also strongly suggested that a certain chemical modification proceeded during the hot water extraction to increase the percentage of the stable free radical. These facts strongly suggested that the mitogenic substance in B. chinense is a polyphenolic substance extracted by hot water, and the structure was modified during the extraction to increase the stable free radical components.

Drugs, Chinese Herbal↗
PubMed1997

Induction of ST-segment elevation by regional myocardial stretch in normal canine hearts in vivo.

The purpose of this study was to evaluate ST-segment elevation induced by regional myocardial stretch without myocardial ischemia in canine hearts. A strain gauge arch (TH-601T) was sutured to the left ventricular epicardium, parallel to the short axis, to shorten the end-diastolic length of the myocardium beneath the arch (stretch zone; SZ) and to produce regional myocardial stretch in each of 6 dogs. An increase in preload caused by altering the height of a saline-filled reservoir affected prolongation or shortening of the myocardium both in the SZ and outside the arch (normal zone; NZ) to increase myocardial stretch. An epicardial electrocardiogram was recorded in both the SZ and the NZ. After suture of the strain gauge arch, the ST segment was elevated in the SZ. An increase in preload augmented stretch during systole in the SZ, resulting in additional ST-segment elevation. These results suggest that regional myocardial stretch itself plays an important role in ST-segment elevation.

Animals↗
PubMed1997

High attenuation lymphadenopathy caused by amyloidosis.

We describe a patient with generalized lymphadenopathy due to amyloidosis which showed on computed tomography as masses with high attenuation. Haemorrhage within lymph nodes caused by vascular amyloid deposition was confirmed at autopsy.

Amyloidosis↗
PubMed1997

[Foreskin retraction for phimosis of the newborn].

BACKGROUND: No guideline exists on how to treat boy's phimosis. We examined if retraction of the foreskin of the newborn boy's penis could make true phimosis become false phimosis. METHODS: We taught the mother to retract the foreskin and keep inside the foreskin clean. Exposure degree of glans by retraction of foreskin was defined in 7 grades, 0 (none) approximately III (middle) approximately VI (full). RESULTS: Of the 538 newborn examined, none had full exposure (VI). All of the 372 cases who continued the procedure, including 2 buried penis, gained full exposure (VI). Average time for full exposure according to the first degree of exposure was 2.94 months (0), 1.78 months (III), 1.22 months (V), 2.32 months average, respectively. No serious complications occurred. CONCLUSION: Retraction of the foreskin from the newborn period made all the true phimosis to be false phimosis and operative procedures became unnecessary.

Health Education↗
PubMed1997

Effects of intravenous anesthetics on the contraction and response of rat trachea to phosphatidylinositol.

Some intravenous anaesthetics have significant effects on the tonicity of airway smooth muscle. There are evidences for a direct relationship between airway smooth muscle contraction and phosphatidylinositol (PI) response. The aims of this study were to clarify 1) the effects of anaesthetics on the cholinergically induced contraction, and 2) the relationship between the effects on the PI response and the contraction. Rat tracheal rings or slices were incubated in Krebs-Henseleit solution containing 5.5 microM carbachol (CCh) in the presence of varying doses of anaesthetics. Thiamylal, fentanyl, ketamine and midazolam all attenuated the CCh-induced contraction. On the other hand, thiamylal augmented inositol monophosphate (IP1) accumulation, whilst ketamine, midazolam and morphine did not have the effect, and fentanyl significantly attenuated IP1 accumulation. These data suggest that airway smooth muscle can be relaxed by intravenous anaesthetics, and that the relaxing effects are not always dependent on the PI system.

Analysis of Variance↗
PubMed1996

Crystal structure of a coagulogen, the clotting protein from horseshoe crab: a structural homologue of nerve growth factor.

The clotting cascade system of the horseshoe crab (Limulus) is involved in both haemostasis and host defence. The cascade results in the conversion of coagulogen, a soluble protein, into an insoluble coagulin gel. The clotting enzyme excises the fragment peptide C from coagulogen, giving rise to aggregation of the monomers. The crystal structure of coagulogen reveals an elongated molecule that embraces the helical peptide C fragment. Cleavage and removal of the peptide C would expose an extended hydrophobic cove, which could interact with the hydrophobic edge of a second molecule, leading to a polymeric fibre. The C-terminal half of the coagulogen molecule exhibits a striking topological similarity to the neurotrophin nerve growth factor (NGF), providing the first evidence for a neurotrophin fold in invertebrates. Similarities between coagulogen and Spatzle, the Drosophila ligand of the receptor Toll, suggest that the neurotrophin fold might be considered more ancient and widespread than previously realized.

Amino Acid Sequence↗
PubMed1996

Molecular cloning of Limulus alpha 2-macroglobulin.

The American horseshoe crab Limulus polyphemus contains alpha 2-macroglobulin (alpha 2M) in the hemolymph plasma and hemocytes. alpha 2M from Limulus shows many of the typical characteristics of mammalian alpha 2M, including the presence of an internal thiol-ester, reactivity with a diversity of endopeptidases, a unique proteinase-trapping mechanism, and reactivity with the mammalian alpha 2M receptor. Additionally, Limulus alpha 2M has the unique property that it regulates the limulin-based hemolytic system of the plasma. A cDNA encoding Limulus alpha 2M has been obtained from a hemocyte cDNA library. The open reading frame encodes an N-terminal signal sequence of 25 amino acid residues and a mature protein of 1482 residues. The entire amino acid sequence is similar to those of the mammalian alpha 2Ms (28-29% identity) and contains common features found in mammalian alpha 2Ms. a bait region, an internal thiol-ester site, and a receptor-binding domain. However, the N-terminal portion (positions 24-105) has no sequence similarity with those of mammalian alpha 2Ms, and it is structurally related to that of the human complement factor C8 chain, consistent with a role for Limulus alpha 2M in host defense. The component sugar analysis of Limulus alpha 2M showed the existence of a complex type of oligosaccharide chain similar to those of mammalian alpha 2M. However, unlike mammalian alpha 2M, no sialic acid was detected in Limulus alpha 2M and it contained approximately 3 mol/mol N-acetylgalactosamine, suggesting the presence of O-linked sugar chains, which have not been found in mammalian alpha 2M. Expression of alpha 2M was detected in hemocytes, but not in hepatopancreas, heart, stomach, intestine, coxal gland, brain and skeletal muscle. Furthermore, immunoblotting of large and small granules of the hemocytes with antiserum against alpha 2M indicated the presence of the alpha 2M in large granules. Trypsin-treated Limulus alpha 2M, but not the native alpha 2M, displaced methylamine-treated human 125I-alpha 2M from the human alpha 2M receptor with a Kd of 30 nM, suggesting conservation of the proteinase-clearance mechanisms between mammalian and arthropod evolutionary lineages.

Amino Acid Sequence↗
PubMed1996

Limulus factor D, a 43-kDa protein isolated from horseshoe crab hemocytes, is a serine protease homologue with antimicrobial activity.

A glycoprotein (Mr = 43,000) from horseshoe crab hemocytes with antimicrobial activity against Gram-negative bacteria was purified. The internal peptide sequences coincided exactly with the deduced amino acid sequence of a cDNA clone, designated limulus factor D, which was isolated by screening a hemocyte cDNA library with an anti-human plasminogen antibody. The open reading frame codes for a precursor of factor D of 394 amino acid residues, including an NH2-terminal signal sequence. The COOH-terminal domain of factor D has significant sequence homology with the catalytic domain of mammalian serine proteases, in particular with human tissue plasminogen activator (32% identity), except for the substitution of Ser of the active site triad to Gly. Factor D has a unique NH2-terminal domain with weak sequence homology with part of the mammalian interleukin-6 receptor alpha-chain. Factor D is likely to have an important role in host defense mechanisms.

Amino Acid Sequence↗
PubMed1996

Molecular mechanism of tissue factor-mediated acceleration of factor VIIa activity.

The mechanism of the acceleration of the catalytic activity of factor VIIa (VIIa) in the presence of tissue factor (TF) was investigated. To explore the VIIa's site(s) that correlates with TF-mediated acceleration, zymogen VII, VIIa, and active site-modified VIIa were prepared, and dissociation constants (Kd) for their bindings to TF or soluble TF in solution were determined. We found that conversion of zymogen VII to VIIa led to an increase in affinity (DeltaDeltaG = 4.3-4.4 kJ/mol) for TFs. Dansyl-Glu-Gly-Arg chloromethyl ketone (DNS-EGRck) treatment of VIIa led to a further increase in the affinity (DeltaDeltaG = 7.3-12 kJ/mol). Neither removal of the Gla domain from VIIa nor truncation of the COOH-terminal membrane and cytoplasmic regions of TF affected the affinity enhanced after DNS-EGRck treatment of VIIa. Treatment of VIIa with (p-amidinophenyl)methanesulfonyl fluoride also enhanced its affinity for soluble TF, whereas treatment with 4-(2-aminoethyl)benzenesulfonyl fluoride, phenylmethylsulfonyl fluoride, or diisopropyl fluorophosphate had a slight effect on the affinity. On the other hand, DNS-EGRck and (p-amidinophenyl)methanesulfonyl fluoride treatments, but not diisopropyl fluorophosphate treatment, of VIIa led to protection of its alpha-amino group of Ile-153 from carbamylation. Protection of the alpha-amino group was consistent with formation of a critical salt bridge between Ile-153 and Asp-343 in the protease domain of VIIa. Therefore, TF may preferentially bind to the active conformational state of VIIa. When one assumes that free VIIa exists in equilibrium between minor active and dominant zymogen-like inactive conformational states, preferential binding of TF to the active state leads to a shift in equilibrium. We speculate that TF traps the active conformational state of VIIa and converts its zymogen-like state into an active state, thereby accelerating the VIIa activity.

Amino Acid Chloromethyl Ketones↗
PubMed1996

Limulus intracellular coagulation inhibitor type 3. Purification, characterization, cDNA cloning, and tissue localization.

We reported that limulus intracellular coagulation inhibitor type-1 (LICI-1) (Miura, Y., Kawabata, S., and Iwanaga, S. (1994) J. Biol. Chem. 269, 542-547) and LICI type-2 (LICI-2) (Miura, Y., Kawabata, S. , Wakamiya, Y., Nakamura, T., and Iwanaga, S. (1995) J. Biol. Chem. 270, 558-565) found in the hemocyte lysate belong to the serpin family. The LICI-1 specifically inhibits limulus lipopolysaccharide-sensitive serine protease, factor C (k1 = 2.5 x 10(6) M-1 s-1), whereas LICI-2 inhibits preferentially limulus clotting enzyme (k1 = 4.3 x 10(5) M-1 s-1). In our ongoing studies on limulus serpin, we found another inhibitor, named LICI type-3 (LICI-3), which strongly inhibits (1,3)-beta-D-glucan-sensitive serine protease, factor G (k1 = 3.9 x 10(5) M-1 s-1). Thus, the limulus hemolymph coagulation cascade is effectively regulated by at least the three endogenous serpins. LICI-3, newly identified in hemocytes, is a single chain glycoprotein with an apparent Mr = 53,000, the largest one among known limulus serpins. A cDNA sequence for LICI-3 coded a mature protein of 392 amino acids, of which 68 residues were confirmed by peptide sequencing. LICI-3 showed significant sequence similarity to LICI-1 (45.8% identity) and LICI-2 (33.7% identity). LICI-3 contained a putative reactive site, -Arg-Ser-, distinct from that of LICI-2 (-Lys-Ser-) but the same as that of LICI-1. Expression of LICI-3 mRNA was detected only in hemocytes, and not in heart, brain, stomach, intestine, coxal gland, and skeletal muscle. Immunoblotting of the hemocyte-derived large and small granules with antiserum against LICI-3 suggested that it is stored specifically in large granules, as in the case of LICI-1 and LICI-2, and is released in response to external stimuli.

Amino Acid Sequence↗
PubMed1996

Limulus kexin: a new type of Kex2-like endoprotease specifically expressed in hemocytes of the horseshoe crab.

A Kex2-like protease was identified in hemocytes of the horseshoe crab (Tachypleus tridentatus), named limulus kexin, and a full-length cDNA was obtained from a hemocyte cDNA library. The deduced amino acid sequence contains 752 residues, composed of five domains with a signal sequence, a propeptide, a catalytic domain, a Ser/Thr-rich domain, and a transmembrane domain. The domain organization is very similar to that of the yeast Kex2 except that limulus kexin does not have a cytoplasmic tail. The catalytic domain exhibits striking sequence identities with those of furins, especially Drosophila furin1 (79%). Northern blotting showed specific expression of limulus kexin in hemocytes, suggesting the involvement in proteolytic processing of the granule components of hemocytes.

Amino Acid Sequence↗
PubMed1996

A new inositol 1,4,5-trisphosphate binding protein similar to phospholipase C-delta 1.

We have reported that two inositol 1,4,5-trisphosphate binding proteins, with molecular masses of 85 and 130 kDa, were purified from rat brain; the former protein was found to be the delta 1-isoenzyme of phospholipase C (PLC-delta 1) and the latter was an unidentified novel protein [Kanematsu, Takeya, Watanabe, Ozaki, Yoshida, Koga, Iwanaga and Hirata (1992) J. Biol. Chem. 267, 6518-6525]. Here we describe the isolation of the full-length cDNA for the 130 kDa Ins(1,4,5)P3 binding protein, which encodes 1096 amino acids. The predicted sequence of the 130 kDa protein had 38.2% homology to that of PLC-delta 1. Three known domains of PLC-delta 1 (pleckstrin homology and putative catalytic X and Y domains) were located at residues 110-222, 377-544 and 585-804 with 35.2%, 48.2% and 45.8% homologies respectively. However, the protein showed no PLC activity to phosphatidylinositol 4,5-bisphosphate and phosphatidylinositol. The 130 kDa protein expressed by transfection in COS-1 cells bound Ins(1,4,5)P3 in the same way as the molecule purified from brain. Thus the 130 kDa protein is a novel Ins(1,4,5)P3 binding protein homologous to PLC-delta 1, but with no catalytic activity. The functional significance of the 130 kDa protein is discussed.

Amino Acid Sequence↗