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Biomedical subjects

S Miyajima

Publications and source records attributed to S Miyajima.

At least 19 recordsLinked to original sources
PubMed2002

An alignment method for mammographic X-ray spectroscopy under clinical conditions.

This paper describes an alignment method for mammographic X-ray spectroscopy under clinical conditions. A pinhole, a fluorescent screen, a laser device and the case for a detector are used for alignment of the focal spot, a collimator and a detector. The method determines the line between the focal spot and the point of interest in an X-ray field radiographically. The method allows alignment for both central axis and off-axis directions.

Calibration↗
PubMed2001

Matrix metalloproteinases induction by pseudomonal virulence factors and inflammatory cytokines in vitro.

The pathogenesis of pseudomonal keratitis was investigated by focusing on induction and activation of matrix metalloproteinases (MMPs) by pseudomonal virulence factors and proinflammatory cytokines. Corneal lesions and MMP induction in vivo were evaluated in rabbit corneas infected with a clinical isolate of Pseudomonas aeruginosa. Effects of pseudomonal virulence factors [elastase, alkaline protease, exotoxin A and lipopolysaccharide (LPS)], tumor necrosis factor (TNF)-alpha and interleukin (IL)-1beta on MMP induction and activation were further examined in vitro in rabbit corneal fibroblasts (RCF) and human fibrosarcoma (HT1080) cells using reverse transcriptase-polymerase chain reaction (RT-PCR), zymography and immunoblotting. Corneal ulcers with typical ring abscesses were observed 12-24 h after infection, and MMPs, particularly MMP-9, were upregulated in infected corneas. Pseudomonal elastase caused the most extensive damage to both cell types. RCF treated with pseudomonal exoproteases or LPS expressed and secreted MMP-9. Exotoxin A had no effect on MMP expression. Both IL-1beta and TNF-alpha augmented MMP-9 expression in HT1080 cells. Pseudomonal elastase proteolytically activated MMP-2 and MMP-9 released from the cells. In conclusion, corneal destruction seen with P. aeruginosa infections may result from enhanced expression of MMPs by corneal stromal cells stimulated with pseudomonal exoproteases and proinflammatory cytokines and the proteolytic activation of MMPs by pseudomonal elastase.

ADP Ribose Transferases↗
PubMed2001

Stimulative effect of cadmium on prostaglandin E2 production in primary mouse osteoblastic cells.

We have reported that cadmium (Cd) stimulates bone resorption via prostaglandin E2 (PGE2), which is mainly produced in osteoblasts. Prostaglandin (PGs) is regulated by arachidonic acid (AA) release by phospholipase A2 (PLA2) and its conversion to PGs by cyclooxygenase (COX). In the present study, we investigated the possibility that Cd-induced PGE2 synthesis was mediated through PLA2 or COX or both using primary mouse osteoblastic cells in serum-free medium. Cd at 1 microM and above stimulated 14C-AA release from 14C-AA-prelabeled osteoblastic cells. PLA2 activity of cytosolic fraction in Cd-treated cells preferentially hydrolyzed AA at the Sn2 position of phospholipids and was inhibited by arachidonyltrifluoromethyl ketone (AACOCF3), an inhibitor of cytosolic PLA2 (cPLA2). Cd at 1 microM and above increased cPLA2 activity and the level of constitutive cPLA2 mRNA. Secretory PLA2 mRNA was not detected. On the other hand, Cd at 1 microM and above stimulated PGE2 production and its production was inhibited by an inhibitor of COX-2 (NS-398). Cd at 1 microM and above markedly stimulated COX-2 mRNA expression and slightly increased the level of COX-1 mRNA. An inhibitor of COX-1 (varelylsalicylic acid) did not affect Cd-induced PGE2 production. In addition, Cd-induced PGE2 synthesis was inhibited by AA-COCF3, On the other hand, IL-1 alpha, an inducer of COX-2, did not stimulated PGE2 production in present culture system. When IL-1 alpha- or Cd-treated cells were incubated with AA for 10 minutes, IL-1 alpha-treated cells as well as Cd-treated ones caused an increase in PGE2 production. This suggests that the mechanism of Cd-induced PGE2 production is different from that of IL-1 alpha, which may require an activation of cPLA2. From these results, it was found that Cd by itself stimulated PGE2 production by two successive steps that Cd increased cPLA2 activity and then COX-2 induction.

Animals↗
PubMed2001

Erythroid involvement in CD36 deficiency.

OBJECTIVE: The CD36 molecule is expressed in platelets, monocytes, erythroblasts, and other different tissues. The two types of platelet CD36 deficiency, types I and II, are associated with the absence and presence of CD36 on monocytes, respectively. To clarify the involvement of the erythroid lineage in CD36 deficiency, we investigated the phenotype and RNA expression of CD36. MATERIALS AND METHODS: CD36 expression was examined in 296 patients with several cardiovascular diseases in our outpatient clinic. There were 12 patients with type I deficiency and 16 with type II CD36 deficiency. A bone marrow sample was examined in five type I and four type II patients. Expression of CD36 mRNA was examined in burst-forming unit-erythroid (BFU-E). The sequences of reverse transcriptase polymerase chain reaction (RT-PCR) products of the CD36 mRNA from monocytes were examined. RESULTS: As expected, CD36 was deficient in erythroblasts from all five patients with type I deficiency. CD36 was present in erythroblasts from three of the four with type II deficiency, suggesting that their abnormality is restricted to platelets (type IIa). CD36 was unexpectedly absent from erythroblasts of a single type II patient (type IIb). CD36-specific mRNA was identified in BFU-E from each of two normals, six type I, and six type II patients, including type IIb. The sequences of RT-PCR products of the CD36 mRNA in a patient with type IIa and another with type IIb showed homozygous wild alleles. CONCLUSION: The findings provide evidence for further heterogeneity among CD36-deficient individuals and the existence of a basic principle mechanism of type II, such as glycosylation abnormality.

Angina Pectoris↗
PubMed2001

Molecular characterization of Bombyx mori cytoplasmic polyhedrosis virus genome segment 4.

The complete nucleotide sequence of the genome segment 4 (S4) of Bombyx mori cytoplasmic polyhedrosis virus (BmCPV) was determined. The 3,259-nucleotide sequence contains a single long open reading frame which spans nucleotides 14 to 3187 and which is predicted to encode a protein with a molecular mass of about 130 kDa. Western blot analysis showed that S4 encodes BmCPV protein VP3, which is one of the outer components of the BmCPV virion. Sequence analysis of the deduced amino acid sequence of BmCPV VP3 revealed possible sequence homology with proteins from rice ragged stunt virus (RRSV) S2, Nilaparvata lugens reovirus S4, and Fiji disease fijivirus S4. This may suggest that plant reoviruses originated from insect viruses and that RRSV emerged more recently than other plant reoviruses. A chimeric protein consisting of BmCPV VP3 and green fluorescent protein (GFP) was constructed and expressed with BmCPV polyhedrin using a baculovirus expression vector. The VP3-GFP chimera was incorporated into BmCPV polyhedra and released under alkaline conditions. The results indicate that specific interactions occur between BmCPV polyhedrin and VP3 which might facilitate BmCPV virion occlusion into the polyhedra.

Amino Acid Sequence↗
PubMed2000

Cell density-dependent regulation of proteoglycan synthesis by transforming growth factor-beta(1) in cultured bovine aortic endothelial cells.

The regulation of vascular endothelial cell behavior during angiogenesis and in disease by transforming growth factor-beta(1) (TGF-beta(1)) is complex, but it clearly involves growth factor-induced changes in extracellular matrix synthesis. Proteoglycans (PGs) synthesized by endothelial cells contribute to the formation of the vascular extracellular matrix and also influence cellular proliferation and migration. Since the effects of TGF-beta(1) on vascular smooth muscle cell growth are dependent on cell density, it is possible that TGF-beta(1) also directs different patterns of PG synthesis in endothelial cells at different cell densities. In the present study, dense and sparse cultures of bovine aortic endothelial cells were metabolically labeled with [(3)H]glucosamine, [(35)S]sulfate, or (35)S-labeled amino acids in the presence of TGF-beta(1). The labeled PGs were characterized by DEAE-Sephacel ion exchange chromatography and Sepharose CL-4B molecular sieve chromatography. The glycosaminoglycan M(r) and composition were analyzed by Sepharose CL-6B chromatography, and the core protein M(r) was analyzed by SDS-polyacrylamide gel electrophoresis, before and after digestion with papain, heparitinase, or chondroitin ABC lyase. These experiments indicate that the effect of TGF-beta(1) on vascular endothelial cell PG synthesis is dependent on cell density. Specifically, TGF-beta(1) induced an accumulation of small chondroitin/dermatan sulfate PGs (CS/DSPGs) with core proteins of approximately 50 kDa in the medium of both dense and sparse cultures, but a cell layer-associated heparan sulfate PG with a core protein size of approximately 400 kDa accumulated only in dense cultures. Moreover, only in the dense cell cultures did TGF-beta(1) cause CS/DSPG hydrodynamic size to increase, which was due to the synthesis of CS/DSPGs with longer glycosaminoglycan chains. The heparan sulfate PG and CS/DSPG core proteins were identified as perlecan and biglycan, respectively, by Western blot analysis. The present data suggest that TGF-beta(1) promotes the synthesis of both perlecan and biglycan when endothelial cell density is high, whereas only biglycan synthesis is stimulated when the cell density is low. Furthermore, glycosaminoglycan chains are elongated only in biglycan synthesized by the cells at a high cell density.

Amino Acids↗
PubMed2000

Acidic electrolysed water in the disinfection of the ocular surface.

Acidic electrolysed water (AEW) is a colorless solution prepared by the electrolysis of sodium chloride solution, which has potent anti-microbial activity against a wide variety of bacteria, fungi and virus. In this study, the safety and efficacy of an isotonic AEW solution (iAEW) was investigated both in vitro and in vivo using denuded corneas of guinea pigs. Povidone iodine (0.01-1.0%) was used as control. Exposure of P. aeruginosa to iAEW for 5 sec caused total inhibition of bacterial growth in vitro. Comparable results were obtained with 1% povidone iodine, while more dilute solutions required longer exposure times for similar effects. Cytotoxicity of iAEW on corneal epithelial cells in vitro was significantly less compared to 1% povidone iodine (P<0.05), while minimal damage was observed in vivo by irrigation of the cornea with either iAEW or 1% povidone iodine. Treatment of P. aeruginosa with iAEW (15 sec) significantly inhibited the onset of corneal infection in guinea pigs. iAEW may offer an effective and safe method for disinfection of the ocular surface.

Disinfectants↗
PubMed2000

Salivary gland MALT lymphoma associated with Helicobacter pylori infection in a patient with Sjögren's Syndrome.

We report a case of salivary gland MALT lymphoma in Sjögren's syndrome associated with localized H. pylori infection. A 76-year-old woman had a history of bilateral cheek masses for two years. Histologically, the parotid glands were invaded by numerous centrocyte-like cells to form lymphoepithelial lesions. The tumor cells showed immunohistological differentiation into B cells. Southern blotting demonstrated immunoglobulin gene rearrangement. These results indicated that the tumors were MALT lymphoma. H. pylori, as assessed by the urease test (CLO test; BML Ltd., Tokyo, Japan), was positive in the tumor specimen. After wide local excision of the tumors followed by radio therapy and oral administration of antibiotics and proton pump inhibitor, no evidence of recurrence was found during the 24-months of follow up. H. pylori infection in the salivary gland is rare, although the source of infection and transmission of H. pylori organisms has been thought to be the oral cavity. We discussed the association between H. pylori infection and salivary gland MALT lymphoma. The microorganism may play a role as an additional antigenic stimulus for the development of salivary gland MALT lymphoma as well as for the development of gastric MALT lymphoma. This means that H. pylori can play a role in lymphoma progression as booster of B cell lymphoproliferation.

Aged↗
PubMed1999

Abnormal fatty acid metabolism in patients with coronary vasospasm.

Although various noninvasive methods have been used to detect vasospasm, none of them are sensitive enough for patients with sporadic attacks. Since abnormal fatty acid metabolism is observed in ischemic myocardium, 123I-beta-methyl-p-iodophenyl pentadecanoic acid (BMIPP), a radiolabeled fatty acid analog, has recently been proposed as a useful tracer for detecting myocardial damage. The aim of this study was to clarify the clinical implications of decreased myocardial BMIPP uptake in patients with vasospastic angina. We evaluated 53 patients with vasospastic angina (32 with clinically documented vasospasm [Group-A] and 21 with vasospasm induced by ergonovine provocation [Group-B]) and 27 control subjects, 20 in Group-A were re-evaluated 6 months after medical treatment. The territorial regions of vasospasm-induced coronary artery, the wall motion by left ventriculography, and BMIPP uptake were compared. Vasospasm was induced in multiple coronary arteries in 29 (55%) patients. Reduced wall motion and decreased BMIPP uptake were observed in 19 (36%) patients and 47 (89%) patients, respectively. The sensitivity and specificity of determination of vasospasm-induced coronary arteries with BMIPP scintigraphy were 71% (69/97 coronary arteries) and 88% (126/143), respectively. Vasospasm was re-induced by ergonovine provocation in 8 patients (Group-I) and not re-induced in 12 (Group-II) after treatment. In Group-I, improvement of decreased BMIPP uptake was lower than in Group-II (19+/-11 vs. 59+/-22%, mean+/-SD, p < 0.001). The regions in which vasospasm was re-provoked exhibited decreased BMIPP uptake. Abnormal fatty acid metabolism was more often observed than wall motion abnormality in the vasospastic region in patients with vasospastic angina. BMIPP scintigraphy is a highly accurate and non-invasive technique for determining the presence and location of vasospasm.

Adult↗
PubMed1999

Two concentric protein shell structure with spikes of silkworm Bombyx mori cytoplasmic polyhedrosis virus revealed by small-angle neutron scattering using the contrast variation method.

The overall and internal structures of the silkworm Bombyx mori cytoplasmic polyhedrosis virus was investigated by small-angle neutron scattering using the contrast variation method. Data were collected in aqueous buffer solutions containing 0, 50, 75, and 100% D2O in the q range of 0.002 to 0.0774 A-1 at 5 degrees C. The radius of gyration at infinite contrast was estimated to be 336 A. The contrast matching point of the virus was determined to correspond to about 50% D2O level, evidence that the virus is composed of protein and nucleic acid. The virus was basically spherical and had a diameter of about 700 A. The main feature of its structure is the clustering of protein into two concentric shells separated by about 100 A. Most of the RNA moieties are located in the central core and between these two protein shells. However, the distance distribution function P(r) showed a minor distribution beyond a distance of r = 700 A, with a maximum particle distance of the virus of 1350 A. This is indicative of an external structure region with very low scattering density, in addition to the basic spherical structure. This external region is thought to correspond to twelve pyramidal protruding spikes shown by electron microscopic studies.

Animals↗
PubMed1998

Nucleotide sequence of Bombyx mori cytoplasmic polyhedrosis virus segment 8.

The segments 8 (S8) of the 10 double-stranded RNA genomes from Bombyx mori cytoplasmic polyhedrosis virus (BmCPV) strains I and H were converted into cDNAs, amplified by PCR, and cloned. The nucleotide sequence analysis of the two full-length S8 cDNAs showed that the segments consist of 1328 nucleotides encoding putative proteins (p44) of 390 amino acids with molecular masses of about 44 kDa, which have glutamic acid-rich and proline-rich domains in their central regions. They had quite high identity with each other: about 98% in nucleotide and amino acid sequences. The recombinant p44 expressed in BmN4 cells using the baculovirus vector was detected by immunoblot analysis. p44 was also confirmed with the same antiserum to be present in BmCPV-infected midgut cells, but not in polyhedra, virus virions and uninfected midgut cells, indicating that p44 is expressed as a nonstructural protein of BmCPV.

Amino Acid Sequence↗
PubMed1998

Characterization of aminopeptidase N from the brush border membrane of the larvae midgut of silkworm, Bombyx mori as a zinc enzyme.

Three GPI-anchored proteins, aminopeptidase N, alkaline phosphatase and alkaline phosphodiesterase I were released from the midgut brush border membrane of Bombyx mori by phosphatidylinositol-specific phopholipase C and the aminopeptidase N was purified to a homogeneous state. N-terminus and 6 internal sequences, one of which possessed part of zinc-binding motif, showed homology with those from other species. The zinc content in purified aminopeptidase N was estimated as approximately 0.72 mol/mol of the protein and 1,10-phenanthroline completely inhibited the enzyme activity, suggesting zinc requirement for the activity. The aminopeptidase N activity was inhibited not only by probestin and actinonin, but also strongly depressed by amastatin, while leuhistin and bestatin were less inhibitory. These suggest that the active site of aminopeptidase N might be structurally different from those of mammals. Calcium and magnesium ions stimulated the aminopeptidase N activity, but copper ion was rather inhibitory. Zinc ion showed bi-modal effect on the activity, i.e., stimulatory at low concentration, but inhibitory at higher than 100 microM. This inhibition was completely restored by EDTA. These results suggest that the aminopeptidase N possesses two zinc ion-binding sites with high and low affinity as essential and inhibitory one, as well as some regulatory metal-binding sites.

Amino Acid Sequence↗
PubMed1998

Myocardial CD36 expression and fatty acid accumulation in patients with type I and II CD36 deficiency.

Long-chain fatty acids (LCFA) are one of the major cardiac energy substrates, so understanding LCFA metabolism may help in elucidating the mechanisms of various heart diseases. CD36 is a multifunctional membrane glycoprotein that acts not only as a receptor for thrombospondin, collagen and oxidized low density lipoprotein but also as a receptor for LCFA. We investigated the relationship between CD36 expression in myocardial capillary endothelial cells and myocardial LCFA uptake in patients with CD36 deficiency. We analyzed CD36 expression in blood cells from 250 patients with heart diseases by means of a flow cytometer. In 218 patients, myocardial LCFA scintigraphy was performed with 123I-beta-methyl-p-iodophenyl pentadecanoic acid (BMIPP). In 5 patients, myocardial capillary endothelial cells were examined immunohistochemically for CD36 expression. Eleven patients (4%) showed signs of type I CD36 deficiency (neither platelets nor monocytes expressed CD36). Twenty patients (8%) had type II CD36 deficiency (monocytes expressed CD36 but platelets did not). In all 11 patients with type I CD36 deficiency, no BMIPP accumulation was observed in the heart, but in 13 patients with type II CD36 deficiency, BMIPP accumulation in the heart was focally reduced, but there were no patients without BMIPP accumulation in the heart. Although the myocardial capillary endothelial cells from two CD36-positive patients expressed CD36, those from two patients with type I CD36 deficiency did not. In a patient with type II CD36 deficiency, some capillary endothelial cells displayed patchy CD36 expression. CD36 deficiency was documented in 31 (12%) patients with heart diseases. Because CD36 was not expressed in the myocardial capillary endothelial cells in patients with type I CD36 deficiency, type I CD36 deficiency is closely related to lack of myocardial LCFA accumulation and metabolism in the myocardium.

Adult↗
PubMed1998

A case of calcinosis universalis successfully treated with low-dose warfarin.

A 27-year-old male patient with calcinosis universalis resulting from dermatomyositis was successfully treated with low-dose warfarin. On his trunk and extremities, there were many subcutaneous calcified nodules, and knee flexion was difficult. After oral warfarin therapy for three years, the calcified nodules became smaller, and the knee mobility improved. His serum vitamin K level was abnormally high, decreased just after starting warfarin therapy, and then remained within the normal range. Since vitamin K has been known to play an important role in the Ca2+ binding process in bones or tissues, we suggest that this therapy is effective in reducing subcutaneous calcification through the vitamin K cycle.

Administration, Oral↗
PubMed1998

Successful slow pathway ablation in a patient with atrioventricular nodal reentrant tachycardia having a proximal common pathway.

Radiofrequency catheter ablation was attempted in a patient with atrioventricular nodal reentrant tachycardia (AVNRT). AVNRT was easily inducible but an intermittent loss of the atrial activation was observed during AVNRT suggesting the presence of a proximal common pathway. During sinus rhythm, a relatively delayed activation that was compatible with a slow potential, was recorded anterior to the ostium of coronary sinus, and radiofrequency catheter ablation application (20 watts) to the site induced junction tachycardia. After an additional radiofrequency catheter ablation application to close the site, AVNRT became noninducible without deterioration of atrioventricular conduction through a fast pathway. This is the first case in which radiofrequency catheter ablation application to the slow potential recording site has been successful, even in AVNRT having a proximal common pathway.

Aged↗
PubMed1998

Determination of the nucleotide sequence of Bombyx mori cytoplasmic polyhedrosis virus segment 9 and its expression in BmN4 cells.

Cloning and sequencing of segment 9 of Bombyx mori cytoplasmic polyhedrosis virus (BmCPV) strains H and I were performed. The segment consisted of 1,186 bp harboring 5' and 3' noncoding regions and an open reading frame from positions 75 to 1037, encoding a protein with 320 amino acids, termed NS5. Comparison of the nucleotide sequences of NS5 for the two strains indicated 37 point differences resulting in only six amino acid replacements. Homology search showed that NS5 has localized similarities to human poliovirus RNA-dependent RNA polymerase and human rotavirus NS26. By Western blot analysis, NS5 was found in BmCPV-infected midgut cells, but not in polyhedra or virus virions, and was mainly detectable in the nucleus in BmCPV-infected BmN4 cells. Immunoblot analysis with anti-NS5 and antipolyhedrin antibodies displayed marked differences in the period of expression of NS5 and polyhedrin: the polyhedrin molecule was first detected 2 or 3 days after infection with BmCPV, whereas the expression of NS5 was initiated within a few hours. In addition, the level of polyhedrin increased as the infection developed, whereas the amount of NS5 remained essentially constant. When segment 9 was expressed with a baculovirus expression system, the resulting NS5 protein possessed the ability to bind to the double-stranded RNA genome. These results suggest that NS5 is expressed in early stages of infection and contributes to regulation of genomic RNA function.

Amino Acid Sequence↗
PubMed1998

Hypertrophic cardiomyopathy with type I CD36 deficiency.

CD36 is a multifunctional membrane-type receptor glycoprotein that reacts with oxidized low-density lipoprotein and long-chain fatty acid (LCFA). A patient presented with hereditary hypertrophic cardiomyopathy (HCM) and type I CD36 deficiency (neither platelets nor monocytes expressed CD36) but showed no myocardial LCFA accumulation. CD36 was expressed in the capillary endothelial cells of the cardiac muscle of a control subject, while the patient's myocardial capillary endothelial cells were completely CD36-negative. These results suggest that type I CD36 deficiency is closely related to hereditary HCM and lack of myocardial LCFA accumulation.

CD36 Antigens↗