Biomedical subjects

M Sugiyama

Publications and source records attributed to M Sugiyama.

At least 73 records · Page 4Linked to original sources

PubMed2001

Change of antimicrobial susceptibility of group B streptococci over 15 years in Japan.

We compared antimicrobial susceptibility patterns of 206 group B streptococcal (GBS) strains isolated from pregnant women and six from neonates/infants with invasive infection during the two periods 1985-1986 and 1999-2000. All strains in both periods were susceptible to the penicillins, cephalosporins and carbapenem tested. Seven (3%) isolates were resistant to erythromycin and three (1%) were resistant to clindamycin. There were no significant differences between the two study periods in the incidence of GBS resistant to the 14 antibiotics tested. These results showed that penicillins are still the first choice to prevent vertical transmission of GBS in Japan.

Anti-Bacterial Agents↗

PubMed2001

Application of nano-diffraction to local atomic distribution function analysis of amorphous materials.

A method is proposed for the local atomic distribution function analysis of amorphous materials. This method is based on local halo-electron diffraction intensity analysis with nano-sized electron probes as small as 25 to approximately 3 nm, taking advantage of the intensity recording with imaging plate. Nanodiffraction and selected area electron diffraction (SAED) patterns from an amorphous SiNx (x approximately 4/3) thin film were taken using a conventional transmission electron microscope operated at 200 kV and recorded on imaging plates. An intensity correction to omit inelastic intensity was made using electron energy-loss spectroscopy. When a beam-convergence angle is larger than 1 x 10(-3) rad, the Wiener-filter deconvolution method becomes helpful in producing atomic pair distribution functions (PDFs) from the nano-diffraction intensity profiles that are more similar to the PDF from the SAED intensity. This technique was applied to the analysis of local amorphous structures of SiO2 layers formed by an oxygen-ion implantation into single crystal SiC.

Journal Article↗

PubMed2001

Use of bleomycin- and heat shock-induced calreticulin promoter for construction of a mammalian expression vector.

Addition of bleomycin (Bm) to an NIH/3T3 cell culture induced the overproduction of four cellular proteins [Kumagai and Sugiyama (1998) J. Biochem. 124, 835-841]. The two proteins were identified on N-terminal amino acid sequence analysis as calreticulin and mitochondrial matrix protein P1, which are known as heat shock proteins, respectively. In this study, we cloned the calreticulin promoter region from the genomic DNA of NIH/3T3 cells and observed that heat shock treatment at 42 degrees C or the addition of Bm to the cell culture caused overexpression of the luciferase gene controlled by the cloned calreticulin promoter. This suggests that Bm induces the transcriptional activation of stress-heat shock genes. We constructed an expression vector for mammalian cells, which is controlled by the calreticulin promoter.

3T3 Cells↗

PubMed2001

Replacements of amino acid residues at subsites and their effects on the catalytic properties of Rhizomucor pusillus pepsin, an aspartic proteinase from Rhizomucor pusillus.

Site-directed mutagenesis was carried out to investigate the functional roles of amino acid residues of Rhizomucor pusillus pepsin (RMPP) in substrate-binding and catalysis. Mutations of two amino acid residues, E13 in the S3 subsite and N219 in the S3/S4 subsites, caused marked changes in kinetic parameters for two substrate peptides with different sequences. Further site-directed mutagenesis at E13 suggested that E13 plays a critical role in forming the correct hydrogen bond network around the active center. In the crystal structure of Rhizomucor miehei pepsin (RMMP), which is an aspartic proteinase produced by Rhizomucor miehei and shows 81% amino acid identity to RMPP, the Oepsilon atom of N219 forms a hydrogen bond with the N-H of isovaline in pepstatin A, a statine-type inhibitor, at the P3 position, suggesting that the loss of the hydrogen bond causes an unfavorable arrangement of the P3 residue. Among the mutants constructed, the E13A mutant showed a 5-fold increase in the ratio of clotting versus proteolytic activity without significant loss of clotting activity. This mutant may present a promising candidate for a useful milk coagulant.

Amino Acid Substitution↗

PubMed2001

An arabinogalactan protein(s) is a key component of a fraction that mediates local intercellular communication involved in tracheary element differentiation of zinnia mesophyll cells.

Local intercellular communication is involved in tracheary element (TE) differentiation of zinnia (Zinnia elegans L.) mesophyll cells and mediated by a proteinous macromolecule, which was designated xylogen. To characterize and isolate xylogen, a bioassay system to monitor the activity of xylogen was developed, in which mesophyll cells were embedded in microbeads of agarose gel at a low (2.0-4.3x10(4) cells ml(-1)) or high density (8.0-9.0x10(4) cells ml(-1)) and microbeads of different cell densities were cultured together in a liquid medium to give a total density of 2.1-2.5x10(4) cells ml(-1). Without any additives, the frequency of TE differentiation was much smaller in the low-density microbeads than in the high-density microbeads. This low level of TE differentiation in the low-density microbeads was attributable to the shortage of xylogen. When cultures were supplemented with conditioned medium (CM) prepared from zinnia cell suspensions undergoing TE differentiation, the frequency of TE differentiation in the low-density microbeads increased remarkably, indicating the activity of xylogen in the CM. The xylogen activity in CM was sensitive to proteinase treatments. Xylogen was bound to galactose-specific lectins such as Ricinus communis agglutinin and peanut agglutinin, and precipitated by beta-glucosyl Yariv reagent. These results indicate that xylogen is a kind of arabinogalactan protein.

Asteraceae↗

PubMed2001

The association of high jugular bulb venous oxygen saturation with cognitive decline after hypothermic cardiopulmonary bypass.

UNLABELLED: This study was conducted to investigate whether jugular bulb venous oxygen saturation (SjVO(2)) predicted cognitive decline after cardiac surgery with hypothermic cardiopulmonary bypass (CPB). We studied 35 patients undergoing cardiac surgery. After the induction of anesthesia, a 5.5F fiberoptic oximetry catheter was retrogradely inserted into the jugular bulb, and SjVO(2) and other cerebral oxygenation variables were analyzed before, during, and after CPB. At each point, an oxyhemoglobin dissociation curve was drawn, and the P(50) value of jugular bulb venous blood was calculated by computer analysis. Cognitive function was assessed with the revised version of Hasegawa's Dementia Scale and the Benton Revised Visual Retention Test before and early after the operation. In 15 patients (the Decline group), cognitive function was declined after surgery, whereas it remained unchanged in 20 patients (the Normal group). SjVO(2) was significantly higher and cerebral oxygen extraction was significantly lower before and during CPB in the Decline group than in the Normal group (P < 0.05). The oxygen pressure at an oxygen saturation of 50% was significantly lower before and after CPB in the Decline group than in the Normal group (P < 0.05). Logistic regression analysis showed that high SjVO(2) was a predictor of cognitive decline after cardiac surgery. We conclude that high SjVO(2) was associated with cognitive decline after cardiac surgery with hypothermic CPB. IMPLICATIONS: Jugular bulb venous oxygen desaturation has been suggested as a predictor of cognitive decline after cardiac surgery. However, the clinical value of jugular bulb venous oxygen saturation (SjVO(2)) may be limited during hypothermic cardiopulmonary bypass (CPB) when oxygen affinity to hemoglobin is increased. This study shows that high SjVO(2) before and during hypothermic CPB is a predictor of subsequent cognitive decline.

Adult↗

PubMed2001

Scintigraphic evaluation of small pulmonary right-to-left shunt and therapeutic effect in pulmonary arteriovenous malformation.

PURPOSE: Right-to-left shunts of pulmonary arteriovenous malformation (PAVM) can be detected and measured by pulmonary perfusion scans using Tc-99m MAA. In PAVM with a relatively small right-to-left shunt, however, measurement of the shunt ratio may not be reliable. This study re-evaluated pulmonary perfusion scans for a small right-to-left shunt of PAVM. METHODS: Tc-99m MAA lung scans were performed in five patients with proved PAVM before and after percutaneous transcatheter embolization. The right-to-left shunt ratio was calculated and extrapulmonary uptake was assessed on total-body images. RESULTS: Lung perfusion scans obtained before embolization revealed brain uptake in four patients, and the shunt ratio ranged from 4.4% to 22.9%. In two patients with a small single PAVM, the shunt ratio was less than 15% before treatment and did not change significantly after successful embolotherapy. The brain uptake, which had been clearly visible before therapy, disappeared after embolization. Renal uptake was seen on pre- and post-therapy scans. CONCLUSIONS: Changes in brain activity visible on Tc-99m MAA scans might be a more reliable sign than a decreased shunt ratio or a change in renal uptake when evaluating embolization therapy in patients with PAVM who have a small right-to-left shunt.

Adult↗

PubMed2001

Opsonin receptor expression on peritoneal exudative and circulatory neutrophils in murine acute pancreatitis.

Acute severe (necrotizing) pancreatitis is often associated with pancreatic or peripancreatic infection. Decreased bacterial clearance due to impaired immune defense may cause local infection. We investigated expressions of surface opsonin receptors (CD11b, complement receptor 3; CD32/CD16, immunoglobulin G Fc receptor) on local and circulatory neutrophils, in murine acute pancreatitis. The mild and severe forms of acute pancreatitis were induced by seven and 13 subcutaneous injections of caerulein, respectively. Peritoneal exudative and circulatory neutrophils were counted and assayed for receptor expressions by flow cytometry, serially at 1-72 hours after pancreatitis induction. Histologically, mild and severe forms showed edematous and necrotizing pancreatitis, respectively. The peritoneal exudative neutrophil count was greater in mild than in severe pancreatitis. Expressions of CD11b and CD32/CD16 on local neutrophils were upregulated early in mild pancreatitis. This upregulation was attenuated in severe pancreatitis. The circulatory neutrophil count was elevated in severe pancreatitis but was unchanged in mild pancreatitis. Opsonin receptor expression on circulatory neutrophils showed a transient, modest upregulation in the early phase of mild pancreatitis. Receptor-positive circulatory neutrophils showed a marked elevation that persisted throughout the course of severe pancreatitis. In conclusion, severe (necrotizing) pancreatitis is associated with reduced opsonin receptor expression on local neutrophils and enhanced expression on circulatory neutrophils, as compared with mild (edematous) pancreatitis. These changes may contribute to local infectious complications and multiple organ failure, in severe pancreatitis.

Acute Disease↗

PubMed2001

A comparison of complete genome sequences of the attenuated RC-HL strain of rabies virus used for production of animal vaccine in Japan, and the parental Nishigahara strain.

In order to establish the molecular basis of the pathogenicity of the attenuated RC-HL strain of rabies virus used for the production of animal vaccine in Japan, the complete genome sequence of this strain was determined and compared with that of the parental Nishigahara strain which is virulent for adult mice. The viral genome of both strains was composed of 11,926 nucleotides. The nucleotide sequences of the two genomes showed a high homology of 98.9%. The homology of the G gene was lower than those of N, P, M and L genes at both nucleotide and deduced amino acid levels, and the percentage of radical amino acid substitutions on the G protein was the highest among the five proteins. These findings raise the possibility that the structure of the G protein is the most variable among the five proteins of the two strains. Furthermore, we found two clusters of amino acid substitutions on the G and L proteins. The relevance of these clusters to the difference in the pathogenicity between the two strains is discussed.

Amino Acid Sequence↗

PubMed2001

The Saccharomyces cerevisiae Isw2p-Itc1p complex represses INO1 expression and maintains cell morphology.

In the yeast Saccharomyces cerevisiae, IRE1 encodes a bifunctional protein with transmembrane kinase and endoribonuclease activities. HAC1 encodes a transcription factor which has a basic leucine zipper domain. Both gene products play a crucial role in the unfolded protein response. Mutants in which one of these genes is defective also show the inositol-auxotrophic (Ino(-)) phenotype, but the reason for this has not been clear. To investigate the mechanism underlying the Ino(-) phenotype, we screened a multicopy suppressor gene which can suppress the Ino(-) phenotype of the Delta hac1 strain. We obtained a truncated form of the ITC1 gene that has a defect in its 3' region. Although the truncated form of ITC1 clearly suppressed the Ino(-) phenotype of the Delta hac1 strain, the full-length ITC1 had a moderate effect. The gene products of ITC1 and ISW2 are known to constitute a chromatin-remodeling complex (T. Tsukiyama, J. Palmer, C. C. Landel, J. Shiloach, and C. Wu, Genes Dev. 13:686--697, 1999). Surprisingly, the deletion of either ITC1 or ISW2 in the Delta hac1 strain circumvented the inositol requirement and caused derepression of INO1 even under repression conditions, i.e., in inositol-containing medium. These data indicate that the Isw2p-Itc1p complex usually represses INO1 expression and that overexpression of the truncated form of ITC1 functions in a dominant negative manner in INO1 repression. It is conceivable that the repressor function of this complex is regulated by the C-terminal region of Itc1p.

Adenosine Triphosphatases↗

PubMed2001

Rescue of rabies virus from cloned cDNA and identification of the pathogenicity-related gene: glycoprotein gene is associated with virulence for adult mice.

In order to identify the viral gene related to the pathogenicity of rabies virus, we tried to establish a reverse genetics system of the attenuated RC-HL strain, which causes nonlethal infection in adult mice after intracerebral inoculation. A full-length genome plasmid encoding the complete antigenomic cDNA of the RC-HL strain and helper plasmids containing cDNAs of the complete open reading frame of the N, P, and L genes, respectively, were constructed. After transfection of these plasmids into BHK-21 cells infected with the T7 RNA polymerase-expressing vaccinia virus, infectious rabies virus with almost the same biological properties as those of the wild-type RC-HL strain was rescued. Using this reverse genetics system of the RC-HL strain, we generated a chimeric virus with the open reading frame of the glycoprotein gene from the parent Nishigahara strain, which kills adult mice after intracerebral inoculation, in the background of the RC-HL genome. Since the chimeric virus killed adult mice following intracerebral inoculation, it became evident that the open reading frame of the glycoprotein gene is related to the pathogenicity of the Nishigahara strain for adult mice.

Animals↗

PubMed2001

Subspace information criterion for model selection.

The problem of model selection is considerably important for acquiring higher levels of generalization capability in supervised learning. In this article, we propose a new criterion for model selection, the subspace information criterion (SIC), which is a generalization of Mallows's C(L). It is assumed that the learning target function belongs to a specified functional Hilbert space and the generalization error is defined as the Hilbert space squared norm of the difference between the learning result function and target function. SIC gives an unbiased estimate of the generalization error so defined. SIC assumes the availability of an unbiased estimate of the target function and the noise covariance matrix, which are generally unknown. A practical calculation method of SIC for least-mean-squares learning is provided under the assumption that the dimension of the Hilbert space is less than the number of training examples. Finally, computer simulations in two examples show that SIC works well even when the number of training examples is small.

Learning↗

PubMed2001

A possible role of apoptosis for regulating autoreactive responses in systemic lupus erythematosus.

It has been reported that apoptotic cells are increased in the peripheral blood from patients with systemic lupus erythematosus (SLE), where dysfunctions of T helper 1 (Th1) cells are known. In order to study whether apoptosis of Th1 cells is associated with the pathogenesis of SLE, early apoptotic cells in various T-cell subsets were detected using fluorescence-labeled annexin V (AnV). AnV binding was most frequently observed in CD4+CCR5+ T cells, and AnV binding rate (%) in this subset was higher in SLE than in normal controls (14.7 +/- 2.6), although that in active SLE (43.6 +/- 7.3) tended to be lower than that in inactive SLE (48.0 +/- 6.8). CD95/Fas expression was also increased in both active and inactive SLE. In some SLE patients, AnV binding rate changed in inverse proportion to titer of the serum anti-DNA antibody and in proportion to serum complement activity. These data suggest that apoptosis in Th1 cells is important in the pathogenesis of SLE and might play a role in regulating over-activation or autoreactive responses by T cells.

Adult↗

PubMed2001

A novel WT1 gene mutation associated with wilms' tumor and congenital male genitourinary malformation.

WT1 is located on the short arm of human chromosome 11 and consists of 10 coding exons. Mutations of this gene have been reported to be the cause of Wilms' tumor, congenital male genitourinary malformations, and/or renal disorders. We describe here a novel WT1 gene mutation, i.e. a point mutation at intron 7 (+2) in both the tumor and the germline cells of a patient with Wilms' tumor and congenital male genitourinary malformation, but without renal disorder. The position of the mutation is at a splice donor site of intron 7, which causes the splicing out of exon 7 and generates a truncated protein. This type of mutation in the WT1 zinc finger domain has not been reported before. The mutation is of paternal origin and is heterozygous in the germline cells. In the tumor cells, however, the maternal allele is largely lost, from 11p12 to 11p15, which results in maternal loss of heterozygosity. These results, together with the data from previous reports, suggest that WT1 may function in gonadogenesis, nephrogenesis, and Wilms' tumor tumorigenesis.

Chromosomes, Human, Pair 11↗

PubMed2001

In vivo effect of pancreatic phospholipase A2 on the arachidonic acid cascade.

BACKGROUND: In acute pancreatitis, pancreatic phospholipase A2 increases in systemic circulation. Yet the pathophysiological significance is controversial, because previous in vitro studies have shown that the enzyme has little cytotoxicity or ability to activate the arachidonic acid cascade by itself in contrast to other isozymes. AIM OF THE STUDY: The aims of this study are to examine the effect of pancreatic phospholipase A2 on the arachidonic acid cascade in vivo; to explain the discrepancy, if present, between in vitro and in vivo findings; and to reassess the pathophysiological significance of circulating pancreatic phospholipase A2. METHODS: Pancreatic phospholipase A2 was infused intravenously in guinea pigs, and changes in the arachidonic acid cascade, plasma lipoprotein, and cardiopulmonary function were investigated. RESULTS: Plasma concentrations of 6-keto-prostaglandin F1alpha, prostaglandin E2, and thromboxane B2 increased after intravenous (iv) infusion of pancreatic phospholipase A2. Some of the plasma phospholipids such as phosphatidylcholine and phosphatidylethanolamine decreased, and free dihomo-gamma-linolenic acid, arachidonic acid, and eicosapentaenoic acid were detected in plasma. These changes were accompanied with decreases in blood pressure, heart rate, and base excess. CONCLUSION: Circulating pancreatic phospholipase A2 activates the arachidonic acid cascade, probably by supplying free eicosanoid precursors from plasma lipoprotein to eicosanoid-producing cells. It is supposed to be a cause of systemic complications in acute pancreatitis.

Animals↗

PubMed2001

Cavernous pancreatic ductal ectasia with smooth muscle proliferation causing recurrent acute pancreatitis.

BACKGROUND: Pancreatic cystic lesions have various etiologies, including pseudocyst (inflammatory cyst), retention cyst, congenital cyst, and neoplastic cyst. RESULTS: This report describes a previously unreported, unique pancreatic cyst-like lesion causing recurrent acute pancreatitis. A 23-yr-old man had an 8 x 5 x 3-cm pancreatic head mass which contained multiple 3-7-mm cysts communicating with the main pancreatic duct on imaging studies. Pancreatoduodenectomy with mass excision prevented further attacks of acute pancreatitis. Pathological examination showed multiple cystic dilatations of branch pancreatic ducts surrounded by proliferating smooth muscle tissue, probably associated with hamartomatous changes. CONCLUSION: We consider the present lesion to represent cavernous pancreatic ductal ectasia with smooth muscle proliferation because of its striking cholangiopancreatographic similarity to Caroli disease.

Acute Disease↗

PubMed2001

Photochromism of viologens included in crown ether cavity.

The effect of a pi-electron-donating macrocyclic molecule on the photochromic behavior of viologen derivatives was investigated in a thin polymer film. The intermolecular interactions between the viologens and the macrocyclic molecule were investigated in a solution before photoirradiation. In acetone, benzylviologens, N,N'-dibenzyl-4,4'-bipyridinium hexafluorophosphate (1) and N,N'-dibenzyl-trans-1,2-bis(4-pyridinium)ethylene hexafluorophosphate (2) each derived from 4,4'-bipiyridine and trans-1,2-bis(4-pyridyl)ethylene, respectively, form an inclusion complex with p-benzocrown ether (3) with binding constants of ca 200 M-1, which was driven by a charge transfer interaction. The peak wavelength of the charge transfer absorption band was at 453 and 421 nm for the inclusion complexes of 1 and 2 with 3, respectively. Upon photoirradiation to the polymer film containing 1, the film changed color from colorless to blue, associated with the reduction of 1 from the dication to the radical cation. The original dication was recovered after 120 min. The addition of 3 into the film containing 1 caused not only the color change from colorless to yellow, associated with the charge transfer interaction between 1 and 3 before photoirradiation, but also an acceleration in the bleaching rate of the photoreduced 1. When p-dimethoxybenzene (4) was used as an acyclic analog of 3, a negligible change in the photochromic behavior of 1 was observed. Similar effect of 3 on the photochromic behavior of 2 was observed. These results imply that the pi-electron-donating macrocyclic molecule causes a faster bleaching of photoreduced viologens by forming the inclusion complex.

Journal Article↗

PubMed2001

Assessment of gadolinium-enhanced time-resolved three-dimensional MR angiography for evaluating renal artery stenosis.

OBJECTIVE: The purpose of this study was to assess the image quality of gadolinium-enhanced time-resolved three-dimensional (3D) MR angiography and to evaluate its accuracy in revealing renal artery stenosis. SUBJECTS AND METHODS: Thirty-nine patients underwent MR angiography using an ultrafast 3D Fourier transform spoiled gradient-recalled acquisition in the steady state (TR/TE range, 2.6/0.7--0.8). Five seconds after administration of 15--20 mL gadodiamide hydrate, four or five consecutive data sets with imaging times of 7.0--7.6 sec were acquired during a single breath-hold. A timing examination was not performed. Image quality was assessed using quantitative analysis (signal-to-noise, contrast-to-noise, and venous-to-arterial enhancement ratios) and qualitative analysis (presence of venous overlap, presence of artifacts, and degree of renal arterial enhancement). MR angiography depiction of the renal artery stenosis was evaluated using conventional angiography as the standard of reference. RESULTS: On the best arterial phase, average aortic signal-to-noise ratio (+/-SD) was 74.5 +/- 24.4, aorta-to--inferior vena cava contrast-to-noise ratio was 70.8 +/- 23.4, and inferior vena cava--to-aorta venous-to-arterial enhancement ratio was 0.03 +/- 0.04. No venous overlap was seen in 38 of 39 patients. Substantial enhancement of renal arteries was seen in all patients without any noticeable artifacts. MR angiography correctly depicted the degree of stenosis in 44 of 47 normal arteries, 13 of 16 mildly stenotic arteries, five of five moderately stenotic arteries, three of four severely stenotic arteries, and one of one occluded artery. Sensitivity and specificity for revealing greater than 50% stenosis was 100%. CONCLUSION: Time-resolved 3D MR angiography can provide high-quality arteriograms. Its performance in revealing renal artery stenosis is comparable with that of conventional angiography.

Adult↗