Biomedical subjects

A Suzuki

Publications and source records attributed to A Suzuki.

At least 145 records · Page 8Linked to original sources

PubMed2001

Application of bone marrow-derived stem cells in experimental nephrology.

Recent advancement in developmental biology has led to the discovery of immature mesenchymal stem cells in bone marrow and several established organs. The therapeutic potentials of such stem cells for treating serious diseases constitute a major rationale for every research effort, and clinical trials for replacing some damaged tissues such as cartilage are currently under way. Although the feasibility of such stem cell therapies for renal diseases remains unknown, it is worthy of pursuing possibilities. As an experimental tool, we have made chimeric rats that carry the bone marrow of transgenic rats expressing green fluorescent protein (GFP) throughout the body. All marrow lineages can be traced with bright green fluorescence regardless of their terminal phenotypes in chimeric rats. When compared with other conventional strategies for tracking bone marrow-derived cells, our system is highly sensitive and allows us to take advantage of the rat nephrology. Using this system, we have reported that bone marrow provides mesangial cells during repair process. In this manuscript, we briefly summarize our experiences.

Animals↗

PubMed2001

Impedance computed tomography using an adaptive smoothing coefficient algorithm.

In impedance computed tomography, a fixed coefficient regularization algorithm has been frequently used to improve the ill-conditioning problem of the Newton-Raphson algorithm. However, a lot of experimental data and a long period of computation time are needed to determine a good smoothing coefficient because a good smoothing coefficient has to be manually chosen from a number of coefficients and is a constant for each iteration calculation. Thus, sometimes the fixed coefficient regularization algorithm distorts the information or fails to obtain any effect. In this paper, a new adaptive smoothing coefficient algorithm is proposed. This algorithm automatically calculates the smoothing coefficient from the eigenvalue of the ill-conditioned matrix. Therefore, the effective images can be obtained within a short computation time. Also the smoothing coefficient is automatically adjusted by the information related to the real resistivity distribution and the data collection method. In our impedance system, we have reconstructed the resistivity distributions of two phantoms using this algorithm. As a result, this algorithm only needs one-fifth the computation time compared to the fixed coefficient regularization algorithm. When compared to the fixed coefficient regularization algorithm, it shows that the image is obtained more rapidly and applicable in real-time monitoring of the blood vessel.

Algorithms↗

PubMed2001

5-hydroxytryptamine strongly inhibits fluid secretion in guinea pig pancreatic duct cells.

We studied the distribution of 5-hydroxytryptamine- (5-HT-) containing cells in the guinea pig pancreas and examined the effects of 5-HT on fluid secretion by interlobular pancreatic ducts. The 5-HT-immunoreactive cells with morphological characteristics of enterochromaffin (EC) cells were scattered throughout the duct system and were enriched in islets of Langerhans. The fluid secretory rate in the isolated interlobular ducts was measured by videomicroscopy. Basolateral applications of 5-HT strongly but reversibly reduced HCO(3)-dependent, as well as secretin- and acetylcholine- (ACh-) stimulated, fluid secretion, whereas 5-HT applied into the lumen had no such effects. Secretin-stimulated fluid secretion could be inhibited by a 5-HT(3) receptor agonist, but not by agonists of the 5-HT(1), 5-HT(2), or 5-HT(4) receptors. Under the stimulation with secretin, 5-HT decreased the intracellular pH (pH(i)) and reduced the rate of pH(i) recovery after acid loading with NH(4)(+), suggesting that 5-HT inhibits the intracellular accumulation of HCO3(-). The elevation of intraductal pressure in vivo reduced secretin-stimulated fluid secretion, an effect that could be attenuated by a 5-HT(3) receptor antagonist. Thus, 5-HT, acting through basolateral 5-HT(3) receptors, strongly inhibits spontaneous, secretin-, and ACh-stimulated fluid secretion by guinea pig pancreatic ducts. 5-HT released from pancreatic ductal EC cells on elevation of the intraductal pressure may regulate fluid secretion of neighboring duct cells in a paracrine fashion.

Acetylcholine↗

PubMed2001

Association of the TaqI A polymorphism of the dopamine D(2) receptor gene with predisposition to neuroleptic malignant syndrome.

OBJECTIVE: The pathophysiology of neuroleptic malignant syndrome is mainly explained by a central hypodopaminergic state. The familial occurrence of neuroleptic malignant syndrome suggests the involvement of a genetic mechanism in the predisposition to the syndrome. Therefore, the authors examined the association between the TaqI A polymorphism of the dopamine D(2) receptor gene (DRD(2)), which alters DRD(2) density and function, and the development of neuroleptic malignant syndrome. METHOD: The subjects were 15 psychiatric patients who had developed neuroleptic malignant syndrome (12 patients with schizophrenia and three with major depression) and 138 patients with schizophrenia who had never developed neuroleptic malignant syndrome. The TaqI A genotypes, A1 and A2 alleles, were determined by the polymerase chain reaction method. RESULTS: The frequency of the A1 allele was significantly higher in the patients who had developed neuroleptic malignant syndrome (56.8%) than in the patients who had not (35.1%). The proportion of the A1 carrier was significantly higher in the patients with neuroleptic malignant syndrome (14 [93.3%] of 15 patients) than in those without the syndrome (79 [57.2%] of 138 patients). CONCLUSIONS: These findings suggest that the TaqI A DRD(2) polymorphism is associated with the predisposition to neuroleptic malignant syndrome.

Adult↗

PubMed2001

Characterization of a protease responsible for truncated actin increase in neutrophils of patients with Behçet's disease.

As described previously (Yamashita S. et al., Biol. Pharm. Bull., 23, 519-522 (2000)), high levels of a truncated actin with an N-terminus of Met-44 were detected in neutrophils of patients with Behcet's disease. Since the increase of the truncated actin in neutrophils of patients may be important for understanding the pathology of Behçet's disease, the mechanism of the truncated actin formation was studied. First, to investigate the presence of a specific protease, which cleaves the actin at the site between Val-43 and Met-44, a peptide with a partial amino acid sequence of actin from the N-terminal Pro-38 to Asp-51 was synthesized as the protease substrate. The synthesized peptide was digested with cytosolic fractions of neutrophils from patients and healthy volunteers, and digestion products were analyzed by C18-reverse phase HPLC. The chromatograms of these samples showed that an endoprotease, which cleaved the peptide at a specific site, was present in cytosolic fractions of neutrophils from patients with Behçet's disease. Then, the effects of various kinds of protease inhibitors on the digestion of the peptide were investigated in order to identify the responsible endoprotease. The digestion of the peptide was suppressed by 4-(2-aminoethyl) benzenesulfonylfluoride (AEBSF, a serine protease inhibitor) and N-methoxysuccinyl-Ala-Ala-Pro-Val chloromethylketone (CMK, a polymorphonuclear (PMN)-elastase inhibitor) in the presence of EDTA. Furthermore, PMN-elastase was found to cleave the substrate peptide and actin at the site between Val-43 and Met-44. These results lead to the conclusion that the PMN-elastase is responsible for cleavage of actin at the N-terminal site between Val-43 and Met-44 in neutrophils from patients with Behçet's disease.

Actins↗

PubMed2001

Enhancing effect of alpha-monoisostearyl glyceryl ether on the percutaneous penetration of indomethacin through excised rat skin.

The enhancing effect of alpha-monoisostearyl glyseryl ether (GE-IS) on the percutaneous penetration of indomethacin (IM) from test solutions in propylene glycol (PG) was investigated using the excised abdominal skin of rats in vitro. The percutaneous penetration of IM into diffusion cells was significantly increased in the presence of 0.2% or 1% (w/w) GE-IS compared with enhancer-free PG solution. Permeation parameters of IM, such as lag time and permeability coefficient, revealed that GE-IS significantly augmented the percutaneous penetration of IM from PG. These results strongly suggested that GE-IS functions as a penetration enhancer of IM through rat skin. To elucidate the mode of action of GE-IS as a penetration enhancer, the solubility of IM in the test solution and the percutaneous penetration of IM through damaged skin from which the stratum corneum had been stripped were investigated. The results suggested that GE-IS acts directly on the stratum corneum and alters the permeability of the skin.

Animals↗

PubMed2001

Possible physiological roles of proteolytic products of actin in neutrophils of patients with Behçet's disease.

A truncated actin with an N-terminus of Met-44 is known to be selectively increased in neutrophils of patients with Behçet's disease and to be generated proteolytically by PMN-elastase (Yamashita S. et al., Biol. Pharm. Bull., 23, 519-522 (2000); Biol. Pharm. Bull., 24, 119-122 (2001)). In this study, the functions of the N-terminal peptide consisting of Asp-2 to Val-43 of beta-actin (42-merP) and the truncated actin with an N-terminus of Met-44 were examined. We first confirmed that the 42-merP existed in the patient plasma. The motility of human peripheral blood neutrophils and neutrophilic granulocytes differentiated from HL-60 cells was suppressed by the 42-merP. Furthermore, when neutrophil-like cells from HL-60 cells were preincubated with 10 nm 42-merP, migration of the cells induced by chemotactic factors such as fMLP and IL-8 was suppressed. The release of PMN-elastase, which is a neutrophil granular enzyme that is responsible for the production of the 42-merP and truncated actin, was suppressed by pretreating the neutrophils with 42-merP before fMLP-stimulation. The truncated actin was unable to polymerize in 0.1 M KCl, suggesting that the increase of truncated actin damages the reconstitution capacity of actin in neutrophils of the patients. These results suggest that the increase of 42-merP and truncated actin in patients with Behçet's disease changes functions of neutrophils

Actins↗

PubMed2001

Multiplicity of aromatic ring hydroxylation dioxygenase genes in a strong PCB degrader, Rhodococcus sp. strain RHA1 demonstrated by denaturing gradient gel electrophoresis.

To address the multiplicity of aromatic ring hydroxylation dioxygenases, we used PCR amplification and denaturing gradient gel electrophoresis (DGGE). The amplified DNA fragments separated into five bands, A to E. Southern hybridization analysis of RHA1 total DNA using the probes for each band showed that band C originated from a couple of homologous genes. The nucleotide sequences of the bands showed that bands A, C, and E would be parts of new dioxygenase genes in RHA1. That of band B agreed with the bphA1 gene, which was characterized previously. That of band D did not correspond to any known gene sequences. The regions including the entire open reading frames (ORFs) were cloned and sequenced. The nucleotide sequences of ORFs suggested that the genes of bands A, C, and E may respectively encode benzoate, biphenyl, and polyhydrocarbon dioxygenases. Northern hybridization indicated the induction of the gene of band A by benzoate and biphenyl, and that of the gene of band C by biphenyl and ethylbenzene, supporting the above notions. The gene of band E was not induced by any of these substrates. Thus the combination of DGGE and Southern hybridization enable us to address the multiplicity of the ring hydroxylation dioxygenase genes and to isolate some of them.

Blotting, Southern↗

PubMed2001

Translational regulation of the mRNA encoding the eukaryotic translation initiation factor 4E in Xenopus.

We have cloned the cDNA for Xenopus eukaryotic translation initiation factor 4E (eIF4E). Here we show that translation of a luciferase mRNA that contains the 5' untranslated region derived from Xenopus eIF4E is active in fertilized eggs, but is repressed in oocytes. The results suggest that the expression of Xenopus eIF4E is regulated at the translation level.

5' Untranslated Regions↗

PubMed2001

Analysis of the isoform of Xenopus euakryotic translation initiation factor 4E.

We have found two isoforms of the eukaryotic translation initiation factor 4E (eIF4E) in Xenopus laevis. These proteins differ in length by 18 amino acids. Overexpression of either of the two eIF4E proteins modestly increase translation in Xenopus oocytes. The results suggest that both of these two isoforms function in translation.

Amino Acid Motifs↗

PubMed2001

Clinicopathological value of somatostatin type 2A and estrogen receptor immunoreactivity in human breast carcinoma.

Somatostatin type 2A (sstr2A) and estrogen receptor (ER) are interrelated regulatory receptors present in normal breast epithelium and in a population of breast carcinomas. ER mediates growth stimulatory effects of estrogens whereas sstr2A mediates growth inhibitory actions of somatostatin. However, much work has been devoted to elucidate the biological role of ER, little is known about sstr2A in breast cancer. In the present study we examined immunoreactivity of sstr2A and ER in 64 breast carcinomas in correlation with tumor size and histological grade (HG), presence of lymph node metastasis (LNM), Nottingham prognostic index (NPI), and the patients' age. ER and sstr2A immunoreactivity were present in 78% and 63% of the breast carcinomas, respectively. Ninety percent of tumors immunoreactive for sstr2A were simultaneously immunoreactive for ER. ER immunoreactivity correlated significantly with lower HG (p = 0.03) and better NPI (p = 0.02). sstr2A immunoreactivity correlated significantly with lower HG (p = 0.012) but not with NPI (p = 0.26). There was no correlation of sstr2A immunoreactivity and tumor size, patients' chronological age or LNM. The results confirm prognostic value of ER immunohistochemistry in breast carcinoma. However sstr2A cannot substitute ER for prognostic evaluation, sstr2A immunoreactivity being significantly associated with lower HG seems to represent an independent prognostic factor in breast carcinoma.

Breast Neoplasms↗

PubMed2001

Tumor cell "dead or alive": caspase and survivin regulate cell death, cell cycle and cell survival.

Cell death and cell cycle progression are two sides of the same coin, and these two different phenomenons are regulated moderately to maintain the cellular homeostasis. Tumor is one of the disease states produced as a result of the disintegrated regulation and is characterized as cells showing an irreversible progression of cell cycle and a resistance to cell death signaling. Several investigations have been performed for the understanding of cell death or cell cycle, and cell death research has remarkably progressed in these 10 years. Caspase is a nomenclature referring to ICE/CED-3 cysteine proteinase family and plays a central role during cell death. Recently, several investigations raised some possible hypotheses that caspase is also involved in cell cycle regulation. In this issue, therefore, we review the molecular basis of cell death and cell cycle regulated by caspase in tumor, especially hepatocellular carcinoma cells.

Animals↗

PubMed2001

Structural characterization of fucose-containing oligosaccharides by high-performance liquid chromatography and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

Eight pyridylamino (PA) derivatives of fucose-containing oligosaccharides, which occur as free oligosaccharides in human milk and also are derived from glycosphingolipids, have been analyzed by high-performance liquid chromatography (HPLC) on normal-phase and reversed-phase columns, and by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. Six out of eight PA-oligosaccharides were clearly separated by both normal- and reversed-phase HPLC at a column temperature of 40 degrees C, but two PA-oligosaccharides, lacto-N-fucopentaose II [Gal beta1-3(Fuc alpha1-4)GlcNAc beta1-3Gal beta1-4GIcPA] and lacto-N-fucopentaose III [Gal beta1-4(Fuc alpha1-3)GlcNAc beta1-3Gal beta1-4GIcPA], were not separated. The two unresolved PA-oligosaccharides were finally separated by reversed-phase HPLC at a column temperature of 11 degrees C. MALDI-TOF mass spectra of PA-oligosaccharides demonstrated pseudo-molecular ions as the predominant signals, therefore information about the molecular mass of each PA-oligosaccharide was easily obtained. Post-source decay (PSD) MALDI-TOF mass spectra of PA-oligosaccharides gave information about the carbohydrate sequences and carbohydrate species of each PA-oligosaccharide by detecting the ions responsible for the cleavage of the glycosidic bonds. The detection limits of the PA-oligosaccharides by HPLC, MALDI-TOF mass spectrometry, and PSD MALDI-TOF mass spectrometry were 20 fmol, 20 fmol, and 2 pmol, respectively. These results suggest that a system including HPLC and MALDI-TOF mass spectrometry or HPLC and PSD MALDI-TOF mass spectrometry is quite useful for the structural characterization of sub-pmol or pmol levels of fucose-containing oligosaccharides, and that these methods could be used for the analysis of various types of oligosaccharides derived from glycoproteins and glycosphingolipids.

Carbohydrate Sequence↗

PubMed2001

UVA irradiation induces energy-independent phospholipid-flip in mammalian plasma membrane.

Translocation from the outer to the inner membrane leaflet (flip) of phospholipids after ultraviolet A (UVA) irradiation was investigated in Chinese hamster ovary cells. Fluorescent 1-palmitoyl-2-[6-[(7-nitro-2-1,3-benzox- adiazol-4-yl)amino]caproyl]-sn-glycero-3-phosphoserine (NBD-labeled phosphatidylserine [NBD-PS]) was used to assay transbilayer lipid movement. A marked increase in flip of NBD-PS was observed immediately after low-dose UVA irradiation which was not lethal and returned to the basal level after 6 h. UVA-induced flip was not attributed to the increase of permeability by UVA irradiation because cells that were negative for staining with propidium iodide also showed increased flip of NBD-PS. Furthermore, the enhancement was independent of adenosine 5'-triphosphate, demonstrating the lack of involvement of phospholipid translocase. Marked increases were also observed in flip of both NBD-phosphatidylethanolamine and NBD-phosphatidylcholine immediately after UVA irradiation, showing that the increase was independent on the head groups of phospholipids. These findings indicated that UVA changes the flip-flop of phospholipids and that the cell membrane is a molecular and cellular target of UVA.

4-Chloro-7-nitrobenzofurazan↗

PubMed2001

[Ilheus arbovirus in wild birds (Sporophila caerulescens and Molothrus bonariensis)].

OBJECTIVE: To report the first Ilheus arboviruses isolated from wild birds and analyze its public health impact. METHODS: Wild birds and mammals were captured using mist nets and Tomahawk traps, respectively. Blood samples were drawn from these animals and inoculated intracerebrally in Swiss suckling mice found in the Parque Ecológico do Tietê, Brazil. The isolates were identified by serological tests, such as hemagglutination, hemagglutination inhibition, complement fixation and neutralization. Besides virus isolation, serum samples were also tested for the presence of hemagglutination inhibition antibodies. RESULTS: Two strains of Ilheus virus were isolated from the bird species Sporophila caerulescens and Molothrus bonariensis. Specific antibodies to Ilheus virus were detected in serum samples of some birds (Columbina talpacoti, Geopelia cuneata, Sicalis flaveola and Molothrus bonariensis), marmosets (Callithrix jacchus and Callithrix penicillata) and coati (Nasua nasua). CONCLUSIONS: Virus isolation and detection of specific antibodies in serum samples of local, migratory and captive birds, captive marmosets and wild coati corroborate the circulation of Ilheus virus in the Parque Ecológico do Tietê. The migrating behavior of some species of wild birds, like Sporophila caerulescens, enables the virus spread to other regions. Taking into consideration its human pathogenicity and the presence of the virus in this area, local authorities should be aware of the risk of infecting the local community.

Animals↗

PubMed2001

Myelodysplastic syndrome accompanied by Addison's disease and multiple autoimmune phenomena: steroid therapy resolved cytopenias and all immune disorders.

We report here a patient with myelodysplastic syndromes (MDS), which was complicated with several autoimmune disorders and asymptomatic immunologic abnormalities. An 82-year-old woman with refractory anemia (RA) rapidly developed thrombocytopenia with the appearance of symptoms such as purpura, fatigue, anorexia, and weight loss. Furthermore, clinical examinations revealed that she also had Addison's disease, rheumatoid arthritis, and autoimmune hematological diseases such as thrombocytopenia and hemolytic anemia. However, the cytopenia and all autoimmune disorders were remarkably improved after she received steroid therapy.

Addison Disease↗

PubMed2001

Churg-Strauss syndrome after reduction of inhaled corticosteroid in a patient treated with pranlukast for asthma.

Recently, various forms of Churg-Strauss syndrome (CSS) have been reported in association with the use of leukotriene receptor antagonists. A 53-year-old woman with a 5-year history of asthma associated with chronic sinusitis presented mononeuropathy, hypereosinophilia, and positive P-ANCA in October 1999. She had been treated with pranlukast (450 mg/day) and beclomethasone dipropionate (BDP) at a dose of 1,200 microg/day which had gradually been tapered to 800 microg/day over the previous 17 months. She was found to have CSS, and 60 mg/day of prednisolone was administered instead of pranlukast, resulting in an improvement of her symptoms and eosinophilia. Later, we confirmed that serum P-ANCA had been positive before the pranlukast treatment, but CSS vasculitis had not appeared at that time. We speculated that an underlying incomplete form of CSS was being masked in this case and that the reduction of inhaled corticosteroid might have been responsible for the unmasking of CSS.

Administration, Inhalation↗

PubMed2001

Effects of aflastatin A, an inhibitor of aflatoxin production, on aflatoxin biosynthetic pathway and glucose metabolism in Aspergillus parasiticus.

Aflastatin A inhibits aflatoxin production by Aspergillus parasiticus via an unknown mechanism. We found that aflastatin A clearly inhibited production of norsolorinic acid, an early biosynthetic intermediate of aflatoxin, at a concentration of 0.25 microg/ml. Reverse-transcriptase polymerase chain reaction (RT-PCR), and real-time quantitative PCR (TaqMan PCR) experiments indicated that the transcription of genes encoding aflatoxin biosynthetic enzymes (pksA, ver-1, and omtA) and a gene encoding a regulatory protein for expression of the biosynthetic enzymes (aflR) were significantly reduced by the addition of aflastatin A. We also found that aflastatin A elevated the glucose consumption and ethanol accumulation by A. parasiticus, and repressed transcription of genes involved in ethanol utilization. These results suggest that aflastatin A inhibits a very early step in aflatoxin biosynthesis prior to the transcription of aflR and can influence glucose metabolism in the fungus.

Aflatoxins↗