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Biomedical subjects

A Nakamura

Publications and source records attributed to A Nakamura.

At least 91 records · Page 5Linked to original sources
PubMed2001

[Epidemiological study on vancomycin-resistant enterococci from fecal samples in the east area of Japan].

Recently, Vancomycin-resistant enterococci (VRE) have become important nosocomial pathogens in the world. In Japan, the VRE-infection was first reported in 1996. However, an epidemiological study on VRE has not been aggressively done in Japan. We conducted a survey study to explore the incidence and antimicrobial susceptibility of vancomycin-resistant enterococci isolated from fecal samples at 45 hospitals in the east area of Japan (Kanto, Koshinetsu, Tohoku, and Hokkaido) during June 1998 to March 1999. The Enterococcosel agar containing vanocomycin (BBL) was used for screening VRE from fecal samples in each hospital. The susceptibilities of the isolates to 8 antimicrobials were determined by the broth microdilution method and the definitions of resistance were based on current standards of the NCCLS standards. The VRE genotypes (vanA, vanB, vanC1, and van C2/3) were confirmed by amplifying the respective genes by PCR. Eight hundred and ninety four strains of enterococci were tested by the microtiter plates hybridization method (WAKUNAGA SEIYAKU, Japan). One thousand five hundred eighty three strains of enterococci were collected from 6,914 patients in 45 hospitals. These strains included 72 (4.5%) strains Enterococcus faecalis, 33 (2.1%) strains Enterococcus faecium, 17 (1.1%) strains Enterococcus avium, 1,040 (65.7%) strains Enterococcus gallinarum, 386 (24.4%) strains Enterococcus cassliflavus, and 35 (2.2%) strains Enterococcus flavescens. These strains of vancomycin-resistant E. faecalis were isolated from 3 patients, two of these 3 strains had van A gene and other one had van B gene. Those 3 strains were in the Kanto area, and 2 of 3 strains were in Tokyo, Generally, though van A type VRE was highly resistaant to both vancomycin and teicoplanin. In our study, two strains of van A type E. faecalis were highly resistant to vancomycin (MICs > 128 micrograms/ml) and susceptible to teicoplanin with MICs 4 micrograms/ml. Those two strains were different in susceptibilities of minocycline and ofloxacin. The result of the analysis of PFGE had also different patterns. VanB type E. fecalis was highly resistant to vancomycin and susceptible to teicoplanin (MICs 0.25 microgram/ml). For ampicillin and imipenem, 3 strains of E. faecalis were susceptible (MIC < or = 1 microgram/ml). One of 562 strains of E. gallinarum had vanB and vanC1 genes and was moderately resistant to vancomycin and susceptible to teicoplanin. All strains of E. casseliflavus and E. flavescens had vanC2/C3 gene only. All strains of E. faecium and E. avium did not detect van genes. From this result, it was supposed that VRE were very rare in the east of Japan.

Enterococcus↗
PubMed2001

Preferential recruitment of ataxin-3 independent of expanded polyglutamine: an immunohistochemical study on Marinesco bodies.

In an immunohistochemical study of Marinesco bodies--a neuronal intranuclear inclusion often seen in neurons of the substantia nigra of patients with hepatic encephalopathy--it was shown that one of the polyglutamine proteins, ataxin-3, is preferentially recruited into this inclusion, whereas other polyglutamine proteins (ataxin-2 and TATA box-binding protein) are not. This suggests that recruitment of each of the polyglutamine proteins may be differently regulated. Because this nuclear inclusion is thought to be formed in response to cellular stress, as occurs in hepatic encephalopathy, even in the absence of an expanded CAG/polyglutamine repeat, recruitment of ataxin-3 and ubiquitin into Marinesco bodies may represent a cellular response to noxious external stimuli unrelated to expanded CAG/polyglutamine.

Aged↗
PubMed2001

LV systolic performance improves with development of hypertrophy after transverse aortic constriction in mice.

Transverse aortic constriction (TAC) is an effective technique for inducing left ventricular (LV) hypertrophy in mice. With the use of transthoracic echocardiography and Doppler measurements, we studied the effects of an acute increase in pressure overload on LV contractile performance and peak systolic wall stress index (WSI) at early time points after TAC and the time course of the development of LV hypertrophy in mice. The LV mass index was similar between TAC and sham-operated mice at postoperative day 1 but progressively increased in TAC mice by day 10. There was no further increase in the LV mass index between postoperative days 10 and 20. On day 1, whereas peak systolic WSI increased significantly, the LV ejection fraction (LVEF) and percent fractional shortening (%FS) decreased in TAC mice compared with sham-operated mice. By day 10, peak systolic WSI, LVEF, and %FS had recovered to baseline levels and were not significantly different between postoperative days 10 and 20. Thus LV systolic performance in mice declines immediately after TAC, associated with increased peak systolic WSI, but recovers to baseline levels with the development of compensatory LV hypertrophy over 10-20 days.

Animals↗
PubMed2001

In vivo complex formation of oxidized alpha(1)-antitrypsin and LDL.

An inactivated form of alpha(1)-antitrypsin (AT) and LDL coelutes in gel permeation chromatography. To characterize and to quantify the amount of this fraction of AT, a monoclonal antibody was established against chloramine T-oxidized AT and named OxAT-4. OxAT-4 recognized the oxidatively modified AT, including hexylaldehyde- or 4-hydroxy-2-nonenal-modified AT, but neither normal active AT nor trypsin/AT complex. Comigration of apoB and oxidized AT was demonstrated by Western blotting analysis of AT-LDL by means of anti-apoB monoclonal antibody and OxAT-4. A complex of oxidized AT and LDL (AT-LDL) was isolated from human plasma LDL by affinity column with an OxAT-4 antibody-coated carrier. AT-LDL was degraded 4 times more effectively by mouse peritoneal macrophages, but this was not mediated by scavenger receptor class A type I. Localization of AT-LDL was detected in human atherosclerotic lesions of the coronary artery, but distribution of it was not completely identical to that of macrophages. In situ hybridization revealed AT expression by macrophages, which were present in intimal layers of the coronary artery. From these findings, we concluded that AT is produced and oxidized by macrophages, then attached to LDL in the intimal layer of the arterial wall. Although AT-LDL that escapes into the blood stream can be cleared by hepatocytes, the remaining AT-LDL may be taken up by macrophages and contribute to the lipid accumulation in arterial wall cells as the early stage of atherogenesis.

Animals↗
PubMed2001

Me31B silences translation of oocyte-localizing RNAs through the formation of cytoplasmic RNP complex during Drosophila oogenesis.

Embryonic patterning in Drosophila is regulated by maternal factors. Many such factors become localized as mRNAs within the oocyte during oogenesis and are translated in a spatio-temporally regulated manner. These processes are controlled by trans-acting proteins, which bind to the target RNAs to form a ribonucleoprotein (RNP) complex. We report that a DEAD-box protein, Me31B, forms a cytoplasmic RNP complex with oocyte-localizing RNAs and Exuperantia, a protein involved in RNA localization. During early oogenesis, loss of Me31B causes premature translation of oocyte-localizing RNAs within nurse cells, without affecting their transport to the oocyte. These results suggest that Me31B mediates translational silencing of RNAs during their transport to the oocyte. Our data provide evidence that RNA transport and translational control are linked through the assembly of RNP complex.

Animals↗
PubMed2001

[Targeting of myosin light chain kinase in vascular smooth muscle cells, and its implication for drug discovery].

We constructed a plasmid vector to have a 1.4-kb insert of myosin light chain kinase (MLCK) cDNA in an antisense direction to express antisense mRNA. The construct was then transfected to SM3, a cell line from vascular smooth muscle cells (VSMCs), producing a few stable transformants. We explained the methods in detail. The down-regulation of MLCK expression in the transfectants was confirmed by both Northern and Western blots. The control showed chemotactic motility to the platelet derived growth factor. However, the transfectants did not show chemotactic motility, indicating the essential role of MLCK in the motility. It was discussed that down-regulation of MLCK expression could be utilized to discover the drug for arteriosclerosis which prevents the proliferating VSMCs from forming arterial plaques.

Amino Acid Sequence↗
PubMed2001

Age-Related decrease in calcitonin gene-related peptide mRNA in the dorsal root ganglia of spontaneously hypertensive rats.

Age-related changes in levels of calcitonin gene-related peptide (CGRP) mRNA of the dorsal root ganglia was studied in 8-, 12- and 15-week-old spontaneously hypertensive rats (SHR) and age-matched normotensive Wistar Kyoto rats (WKY). CGRP mRNA levels in SHR but not in WKY decreased with age. The contents of CGRP-like immunoreactivities in the atrium and mesenteric artery of 15-week-old SHR were greater than those in age-matched WKY. These results suggest that the outflow of CGRP-containing nerves from the spinal cord and CGRP release from CGRP nerve terminals decreases in SHR.

Aging↗
PubMed2001

Analysis of structural components and molecular construction of soybean soluble polysaccharides by stepwise enzymatic degradation.

Soybean soluble polysaccharides (SSPS) extracted from soybean cotyledons have a pectin-like structure. The core polysaccharides after treatments with four kinds of hemicellulases and a pectinase contained approximately equal numbers of L-rhamnose and D-galacturonate residues, suggesting the presence of the rhamnogalacturonan (RG) I structure consisting of the diglycosyl repeating unit, -4)-alpha-D-GalpA-(1-->2)-alpha-L-Rhap-(1-. The lengths of RG chains were calculated as approximately 15, 28, and 100 diglycosyl repeats. The RG components linked to each other by intervention of galacturonan (GN) chains, constituting the backbone of SSPS. All arabinose residues, which constitute 21% of total SSPS sugars, were found to be in side chains from RG regions, and this was also true for galactose residues, which constitute 50% of total sugars. Of arabinose residues, 94% are present as alpha-1,3- or alpha-1,5-arabinans, and 89% of galactose residues were present as beta-1,4-galactans. Galactan chains are modified with arabinose, xylose, fucose, and glucose at the sites close to the RG regions.

Arabinose↗
PubMed2001

Spontaneous eosinophilic granulated round cell tumors in rats.

Morphologic and histochemical characteristics were noted for three spontaneous tumors with eosinophilic cytoplasmic granules that occurred in aged Fischer 344 rats. Macroscopic lesions were widely distributed in the body, mainly involving the intra-abdominal adipose tissue, pancreas, and mesenterium. These lesions were generally hard swellings with nodular and sclerosing areas. Bloody ascites was a concomitant finding. Histologically, the tumor cells were round, from 9 to 30 microm in diameter with one or two round to oval nuclei, and characterized by eosinophilic granules (0.5-2.0 microm) that stained definitely to weakly positive with the periodic acid-Schiff reaction and demonstrated no metachromasia with toluidine blue stain. Furthermore, the granules were characterized by a positive reaction with lectin histochemistry for concanavalin A (Con A), wheat germ agglutinin (WGA), phaseolus vulgaris agglutinin (PHA-E4), lens culinaris agglutinin (LCA), and recinus communis agglutinin (RCA-I) in all tumors and for ulex europaeus agglutinin (UEA-I), peanut agglutinin (PNA), and soybean agglutinin (SBA) in one tumor. Positive reactions for anti-rat mast cell protease II and CD8 were not demonstrated immunohistochemically. Abundant glycogen was noted in the large tumor cells from one rat. With electron microscopy, the cytoplasmic granules were identified as electron-dense homogenous bodies bounded by a single unit membrane. These characteristics are similar to those of granulated metrial gland cells, but further study is needed to clarify the cell of origin for these tumors.

Abdominal Neoplasms↗
PubMed2001

Separation and determination of minor photosynthetic pigments by reversed-phase HPLC with minimal alteration of chlorophylls.

Reversed-phase HPLC conditions for separation of chlorophyll (Chl) a, Chl a' (the C132-epimer of Chl a), pheophytin (Pheo) a (the primary electron acceptor of photosystem (PS) II), and phylloquinone (PhQ) (the secondary electron acceptor of PS 1), have been developed. Pigment extraction conditions were optimized in terms of pigment alteration and extraction efficiency. Pigment composition analysis of light-harvesting complex II, which would not contain Chl a' nor Pheo a, showed the Chl a'/Chl a ratio of 3-4 x 10(-4) and the Pheo a/Chl a ratio of 4-5 x 10(-4), showing that the conditions developed here were sufficiently inert for Chl analysis. Preliminary analysis of thylakoid membranes with this analytical system gave the PhQ/Chl a' ratio of 0.58 +/- 0.03 (n = 4), in line with the stoichiometry of one molecule of Chl a' per PS I.

Chlorophyll↗
PubMed2001

Normal-phase HPLC separation of possible biosynthetic intermediates of pheophytin a and chlorophyll a'.

Normal-phase HPLC conditions have been developed for separating the C17(3) isoprenoid isomers, which are expected to be formed as biosynthetic intermediates of chlorophyll (Chl) a, Chl a' (C13(2)-epimer of Chl a), pheophytin (Pheo) a and protochlorophyll (PChl). The application of these conditions to pigment composition analysis of greening etiolated barley leaves allowed us to detect, for the first time, the C17(3) isomers of Chl a', a possible constituent of the primary electron donor of photosystem (PS) I, P700, and those of Pheo a, the primary electron acceptor of PS II, in the very early stage of greening. The C17(3) isomer distribution patterns were approximately the same between Chl a and Chl a', but significantly different between Pheo a and Chl a', probably reflecting the similarity and difference, respectively, in the biosynthetic pathways of these pigment pairs.

Carbohydrate Sequence↗
PubMed2001

Prognostic impact of CD45 antigen expression in high-risk, childhood B-cell precursor acute lymphoblastic leukemia.

To evaluate the clinical implications of CD45 expression in acute childhood lymphoblastic leukemia (ALL), we measured the CD45 expression of blast cells from 133 untreated patients with childhood B-precursor ALL (n = 118) or T-ALL (n = 15). CD45 expression (> or = 20%) was detected in all 15 cases (100%) of T-ALL, and 101 cases (86%) of B-precursor ALL. In 122 cases, the fluorescence intensity of the CD45 expression was measured as a relative value; the ratio of average linear values (RALV) of CD45 on the blasts to that on CD3-positive T-lymphocytes from the same specimen. The expression was more intense in the T-ALL cases than in the B-precursor ALL cases (RALV, mean +/- SE: T-ALL 0.230 +/- 0.04 vs. pro-B ALL 0.150 +/- 0.012/pre-B ALL 0.153 +/- 0.019, p < 0.05). However, the intensity of the CD10, CD19, CD20 and CD34 antigen immunoreactivity did not correlate with the CD45 expression. Patients with hyperdiploidy (chromosome number > 50) showed significantly lower levels of CD45 expression than patients with t(1;19) or normal karyotypes (RALV, mean +/- SE: 0.081 +/- 0.022 vs. 0.133 +/- 0.03/0.143 +/- 0.019, p < 0.05). Other clinical features such as age, gender and WBC count did not correlate with CD45 expression. The prognostic implications of CD45 expression were studied in non-high-risk (low-risk + intermediate-risk) (n = 60) and high-risk patients (n = 52) with B-precursor ALL who had been treated with the risk-directed protocol of ALL-941 trial. Although CD45 expression did not correlate with the event-free survival (EFS) of the non-high-risk patients, there was a significant correlation between the expression levels and the EFS of the high-risk patients: the 3-year EFS rate of the CD45low group (n = 26, RALV = 0.017-0.132) was 88 +/- 7% versus the CD45high group (n = 26, RALV = 0.133-0.450) at 34 +/- 24% (p < 0.05). These results show that the levels of expression of the CD45 antigen on leukemic lymphoblasts are significantly correlated with the clinical features and prognosis of childhood ALL.

Antigens, CD↗
PubMed2001

[A patient who developed dermatomyositis during the 1st trimester of gestation and improved after abortion].

This patient was a 30-year-old woman who was in the 8th week of her first pregnancy with three embryos. She developed fever, myalgia and weakness of the proximal muscles, and erythema of the face, dorsal aspects of elbows, and knees. Routine blood examinations showed elevated serum CK. Immunologically, an anti-Jo-1 antibody was positive. Skin biopsy revealed mucinosis and edema in the superficial layer of the corium, and liquid alternation in the basal layer of the epidermis. From these findings, this patient was diagnosed as having dermatomyositis. She was placed on oral prednisolone (80 mg daily), but her clinical symptoms did not improve and all fetuses died by the 11th week of gestation. Then she underwent dilation and curettage and after this operation her disease rapidly subsided. It seemed that fetuses were causatively related to the development of dermatomyositis possibly by changing maternal immune condition. There were six reported cases with dermatomyositis/polymyositis who developed during the first trimester of gestation. Four of these 6 patients were treated with oral steroid; however, only one patient ended in normal delivery. More aggressive therapy, other than corticosteroid, may be required to improve fetal prognosis.

Abortion, Spontaneous↗
PubMed2000

Mechanism of superoxide anion generation in the toxic red tide phytoplankton Chattonella marina: possible involvement of NAD(P)H oxidase.

Red tide phytoplankton Chattonella marina is known to produce reactive oxygen species (ROS), such as superoxide anion (O(2)(-)), hydrogen peroxide (H(2)O(2)) and hydroxyl radical (&z.rad;OH), under normal physiological conditions. Although several lines of evidence suggest that ROS are involved in the mortality of fish exposed to C. marina, the mechanism of ROS generation in C. marina remains to be clarified. In this study, we found that the cell-free supernatant prepared from C. marina cells showed NAD(P)H-dependent O(2)(-) generation, and this response was inhibited by diphenyleneiodonium, an inhibitor of mammalian NADPH oxidase. When the cell-free supernatant of C. marina was analyzed by immunoblotting using antibody raised against the human neutrophil cytochrome b558 large subunit (gp91phox), a main band of approximately 110 kDa was detected. The cell surface localization of the epitope recognized with this antibody was also demonstrated in C. marina by indirect immunofluorescence. Furthermore, Southern blot analysis performed on genomic DNA of C. marina with a probe covering the C-terminal region of gp91phox suggested the presence of a single-copy gene coding for gp91phox homologous protein in C. marina. These results provide evidence for the involvement of an enzymatic system analogous to the neutrophil NADPH oxidase as a source of O(2)(-) production in C. marina.

Amino Acid Sequence↗
PubMed2000

Thermal transitions in the bilayer assembly of dimyristoylphosphatidylglycerol sodium salt dispersion in water: a new phase transition through an intermediate state.

The thermal properties of the dispersion of sodium salt of dimyristoylphosphatidylglycerol (NaDMPG) in water have been investigated as functions of incubation temperature and aging time by DSC, XRD, sodium ion activity, pH, zeta-potential, and IR measurements. The DSC charts for NaDMPG dispersions incubated below 30 degrees C showed an endothermic peak at 31.7 degrees C with a small shoulder peak at Tm (gel-liquid crystal transition temperature: 23.5 degrees C). The temperature of 31.7 degrees C coincides with the T* temperature at which a high-order transition in the NaDMPG bilayer assembly has been found to occur in our previous studies. However, no peak was observed for the dispersions incubated above 32 degrees C. These results indicate that thermal properties of NaDMPG bilayers definitely differ below and above the T* temperature. The dispersion which had been once incubated at 40 degrees C for 24 h never showed the endothermic peak at T* even after the further aging at 3 degrees C for 12-day. Namely, the NaDMPG bilayer assembly exhibits an intensive thermohysteresis. The XRD charts for the NaDMPG dispersions incubated at 25 degrees C showed a sharp X-ray diffraction pattern corresponding to the repeat distance of d = 4.75 nm regardless of their aging time, while the dispersions incubated at 40 degrees C had no diffraction peak until 9-day elapsed. After 10-day aging at 40 degrees C, however, a diffraction peak corresponding to d = 5.55 nm clearly appeared. In the DSC measurements for the dispersion incubated at 40 degrees C, a few endothermic peaks began to appear between Tm and T* after approximately 7-day aging. Then, they shifted toward higher temperatures and finally converged into a single peak at 40-42 degrees C after 14-day aging. These XRD and DSC peaks observed after a long period of aging time above T* suggest that conformations of the hydrophilic groups and the hydrocarbon chains in the NaDMPG bilayers take a more tight and closer arrangement very slowly via an intermediate state above T*, and a new gel phase of the bilayers is consequently formed, the transition temperature (T(I) temperature) of which is 40-42 degrees C. A molecular interpretation for such transition processes in the bilayer assembly of NaDMPG dispersions has been proposed on the basis of pH, sodium ion activity, zeta-potential, IR data, etc.

Calorimetry, Differential Scanning↗