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Biomedical subjects

H Matsuda

Publications and source records attributed to H Matsuda.

At least 181 records · Page 10Linked to original sources
PubMed2001

[A case of short-bowel syndrome treated with parenteral nutrition at home--its effectiveness on improving nutritional status and quality of life].

Although the effectiveness of home parenteral nutrition (HPN) for short-bowel syndrome has already been demonstrated, there are some patients who suffer from severe malnutrition because they cannot be treated with this therapy. We here report the case of a patient with short-bowel syndrome due to massive bowel resection after superior mesenteric artery thrombosis. As she had not received adequate nutritional support, she became severely undernourished and her activities of daily life were very limited during two years after the operation. She was introduced to our department and HPN was initiated. Her nutritional status and quality of life rapidly improved. Thus, we further confirmed the effectiveness of HPN for ambulatory patients with short-bowel syndrome. It is important to take measures not to make patients with short-bowel syndrome, suffering from severe malnutrition without adequate nutritional support, HPN.

Adult↗
PubMed2001

A graph-based clustering method for a large set of sequences using a graph partitioning algorithm.

A graph-based clustering method is proposed to cluster protein sequences into families, which automatically improves clusters of the conventional single linkage clustering method. Our approach formulates sequence clustering problem as a kind of graph partitioning problem in a weighted linkage graph, which vertices correspond to sequences, edges correspond to higher similarities than given threshold and are weighted by their similarities. The effectiveness of our method is shown in comparison with InterPro families in all mouse proteins in SWISS-PROT. The result clusters match to InterPro families much better than the single linkage clustering method. 77% of proteins in InterPro families are classified into appropriate clusters.

Algorithms↗
PubMed2001

Three-dimensional flow velocity quantification of Freestyle aortic stentless bioprosthesis by magnetic resonance imaging: surgical consideration.

The characteristics in flow dynamics of stentless bioprosthetic valve implanted in aortic position has been reported using Doppler echocardiography and beneficial results have been demonstrated in patients. Because some disturbed flow characteristics were seen clinically with existence of pressure gradient, the nature of flow-velocity characteristics was evaluated in patients receiving Freestyle stentless aortic bioprosthesis using new three-dimensional MRI method. In 19 patients after AVR with Freestyle bioprosthesis, flow-velocity study was conducted using velocity-encoding phase-contrast magnetic resonance imaging (MRI). Three-dimensional flow profiles were reconstructed. The implantation techniques were subcoronary (SC) in 10, root inclusion (Incl) in 6, and full root (FR) in 3 patients. These results were compared to 4 pts with stented bioprosthesis and 4 healthy volunteers. In 3-D flow velocity profiles, there were variations from almost normal pattern to some disturbed flow pattern. All patients of FR showed the parabolic flow pattern nearly equal to normal subjects. Over half of the patients with SC and Incl showed disturbed flow pattern with increased pressure gradient. Although hemodynamically acceptable, Freestyle aortic bioprosthesis showed some degree of flow disturbance in subcoronary or inclusion method with increased transvalvular velocity that may cause late problems, and these findings evaluated by 3-D method should be implicated in surgical consideration.

Aged↗
PubMed2001

[Guideline of antimicrobial therapy in the area of cardiovascular surgery].

Although cardiovascular surgery is considered to be aseptic, prolonged hospital stay before and after surgery, the use of artificial materials and cardiopulmonary bypass, long-term use of intratracheal tubes or intravenous catheters, and an increase in surgeries on high-risk patients increase the incidence of postoperative infections. Therefore meticulous management to minimize bacterial contamination before and after surgery and identification of patient risk factors are important to reduce their incidence and severity, in addition to optimal antimicrobial therapy. As the targets of prophylactic antibiotics are usually superficial and environmental bacteria, those of choice are first or second-generation cephalosporins or penicillin with sulbactam. If postoperative infection is suspected, identification of the infectious site and pathogens and their susceptibility to anitimicrobials is useful to control infections. The use of broad-spectrum antibiotics is not recommended because these drugs induce bacterial resistance to antibiotics. Infectious endocarditis (IE) and deep wound infections, such as mediastinitis, are major serious infections after cardiovascular surgery. Antibiotics should be selected by considering the susceptibility of pathogens and pharmacokinetic properties of antibiotics, such as concentration in infected tissue. In patients reluctant to medical therapies, surgical intervention such as valve repair or replacement in IE and debridement and omental flap in mediastinitis should be considered.

Cardiovascular Surgical Procedures↗
PubMed2001

[A case of multiple emphysematous bullae treated with living-donor lung transplantation from identical twin brothers].

A 30-year-old man with multiple emphysematous bullae and bronchiectasis was admitted to Toyama Medical and Pharmaceutical University Hospital because of exertional dyspnea and fever. His chest radiograph and CT scan revealed multiple large bullae in the right lung and infiltrative shadows in the left middle lung field. Pseudomonas aeruginosa was isolated from his sputum culture. Although standard therapies including various antibiotics were administered, his respiratory condition was exacerbated, accompanied with the enlargement of bullae in the right lung and the consequent shift of the mediastinum to the left. The patient and his family proposed lung transplantation, and we concluded that lung transplantation would be an appropriate treatment for his disease. We transported the patient to Osaka University Hospital. Living-donor lung transplantation from the patient's identical twin brothers was successfully performed.

Adult↗
PubMed2000

Dimer formation of octaprenyl-diphosphate synthase (IspB) is essential for chain length determination of ubiquinone.

Ubiquinone (Q), composed of a quinone core and an isoprenoid side chain, is a key component of the respiratory chain and is an important antioxidant. In Escherichia coli, the side chain of Q-8 is synthesized by octaprenyl-diphosphate synthase, which is encoded by an essential gene, ispB. To determine how IspB regulates the length of the isoprenoid, we constructed 15 ispB mutants and expressed them in E. coli and Saccharomyces cerevisiae. The Y38A and R321V mutants produced Q-6 and Q-7, and the Y38A/R321V double mutant produced Q-5 and Q-6, indicating that these residues are involved in the determination of chain length. E. coli cells (ispB::cat) harboring an Arg-321 mutant were temperature-sensitive for growth, which indicates that Arg-321 is important for thermostability of IspB. Intriguingly, E. coli cells harboring wild-type ispB and the A79Y mutant produced mainly Q-6, although the activity of the enzyme with the A79Y mutation was completely abolished. When a heterodimer of His-tagged wild-type IspB and glutathione S-transferase-tagged IspB(A79Y) was formed, the enzyme produced a shorter length isoprenoid. These results indicate that although the A79Y mutant is functionally inactive, it can regulate activity upon forming a heterodimer with wild-type IspB, and this dimer formation is important for the determination of the isoprenoid chain length.

Alkyl and Aryl Transferases↗
PubMed2000

Alteration of V beta usage and cytokine production of CD4+ TCR beta beta homodimer T cells by elimination of Bacteroides vulgatus prevents colitis in TCR alpha-chain-deficient mice.

A major pathogenic factor for the development of inflammatory bowel disease (IBD) is the breakdown of the intestinal homeostasis between the host immune system and the luminal microenvironment. To assess the potential influence of luminal Ags on the development of IBD, we fed TCR alpha(-/-) mice an elemental diet (ED). ED-fed TCR alpha(-/-) mice showed no pathologic features of IBD, and their aberrant mucosal B cell responses were suppressed. Similar numbers of CD4(+), TCR betabeta homodimer T cells (betabeta T cells) were developed in the colonic mucosa of ED-fed mice; however, Th2-type cytokine productions were lower than those seen in diseased regular diet (RD)-fed mice. The higher cytokine production in diseased RD-fed mice could be attributed to the high incidence of Bacteroides vulgatus (recovered in 80% of these mice), which can induce Th2-type responses of colonic CD4(+), betabeta T cells. In contrast, ED-fed TCR alpha(-/-) mice exhibited a diversification of Vbeta usage of betabetaT cell populations from the dominant Vbeta8 one associated with B. vulgatus in cecal flora to Vbeta6, Vbeta11, and Vbeta14. Rectal administration of disease-free ED-fed mice with B. vulgatus resulted in the development of Th2-type CD4(+), betabeta T cell-induced colitis. These findings suggest that the ED-induced alteration of intestinal microenvironments such as the enteric flora prevented the development of IBD in TCR alpha(-/-) mice via the immunologic quiescence of CD4(+), betabeta T cells.

Administration, Rectal↗
PubMed2000

Possible involvement of dopamine and dopamine2 receptors in the inhibitions of gastric emptying by escin Ib in mice.

It was previously reported that escin Ib isolated from horse chestnut inhibited gastric emptying (GE) in mice, in which the capsaicin-sensitive sensory nerves (CPSN), the central nervous system and endogenous prostaglandins (PGs) were involved. In the present study, the possible involvement of dopamine and dopamine receptors in the inhibition of GE by escin Ib were investigated in mice. GE inhibition by escin Ib (25 mg/kg, p.o.) was attenuated after pretreatment with a single bolus of DL-alpha-methyl-p-tyrosine methyl ester (400 mg/kg, s.c., an inhibitor of tyrosine hydroxylase), reserpine (5 mg/kg, p.o., a catecholamine depletor), 6-hydroxydopamine (80 mg/kg, i.p., a dopamine depletor). Furthermore, pretreatment with spiperone (0.5-5 mg/kg, s.c., a dopamine2 receptor antagonist), haloperidol (0.5-10 mg/kg, s.c.) and metoclopramide (1-10 mg/kg, s.c.) (centrally acting dopamine2 receptor antagonists) attenuated the effect of escin Ib. Domperidone (0.1-5 mg/kg, s.c., a peripheral-acting dopamine2 antagonist) showed a weak attenuation, but SCH 23390 (1-5 mg/kg, s.c., a dopamine, receptor antagonist) did not. It is postulated that escin Ib inhibits GE, at least in part, mediated by CPSN, to stimulate the synthesis and/or release of dopamine, to act through central dopamine2 receptor, which in turn causes the release of PGs.

Animals↗
PubMed2000

Automatic detection of conserved gene clusters in multiple genomes by graph comparison and P-quasi grouping.

We previously reported two graph algorithms for analysis of genomic information: a graph comparison algorithm to detect locally similar regions called correlated clusters and an algorithm to find a graph feature called P-quasi complete linkage. Based on these algorithms we have developed an automatic procedure to detect conserved gene clusters and align orthologous gene orders in multiple genomes. In the first step, the graph comparison is applied to pairwise genome comparisons, where the genome is considered as a one-dimensionally connected graph with genes as its nodes, and correlated clusters of genes that share sequence similarities are identified. In the next step, the P-quasi complete linkage analysis is applied to grouping of related clusters and conserved gene clusters in multiple genomes are identified. In the last step, orthologous relations of genes are established among each conserved cluster. We analyzed 17 completely sequenced microbial genomes and obtained 2313 clusters when the completeness parameter P: was 40%. About one quarter contained at least two genes that appeared in the metabolic and regulatory pathways in the KEGG database. This collection of conserved gene clusters is used to refine and augment ortholog group tables in KEGG and also to define ortholog identifiers as an extension of EC numbers.

Algorithms↗
PubMed2000

N-acetylated-alpha-linked-acidic dipeptidase inhibitor has a neuroprotective effect on mouse retinal ganglion cells after pressure-induced ischemia.

Excessive glutamate receptor activation is thought to be involved in the retinal ganglion cell (RGC) death after ischemic injury. In this study, we examined the effect of 2-PMPA (2-(phosphonomethyl)pentanedioic acid) on RGC survival in an ischemia-reperfusion model using C57BL/6 mouse eyes. 2-PMPA is a NAALADase (N-acetylated-alpha-linked-acidic dipeptidase) inhibitor, an enzyme responsible for the hydrolysis of the neuropeptide NAAG (N-acetyl-aspartyl-glutamate) to N-acetyl-aspartate and glutamate. 100mg/kg 2-PMPA were given with intraperitoneal injections 30 min before ischemia followed per hour injection for 3h. 2-PMPA increased surviving RGCs as well as retinal thickness after pressure-induced retinal ischemia. In addition, neuroprotection afforded by 2-PMPA was greater than that of N-methyl-D-aspartate receptor blocker. These data indicate that NAALADase inhibition may be useful in retinal disorders in which excessive amino acid transmission is pathogenic.

Animals↗
PubMed2000

Mercury emissions from a coal-fired power plant in Japan

The emissions study for mercury was conducted at a 700 MW coal-fired plant for the combustion of three types of coal with mercury concentrations of 0.0063, 0.0367 and 0.065 mg/kg. The power plant is equipped with a cold-side electrostatic precipitator and wet type flue gas desulfurization system. During full load operation of the boilers, samples of the input and output streams such as coal, coal ash, ESP ash and post-ESP particulates and flue gas were collected. The Hg concentrations in solid were measured by cold-vapor atomic absorption spectrometry (AAS) after appropriate preparation and acid digestion. Gaseous Hg was collected using a mixed solution of potassium permanganate and sulfuric acid and the Hg concentrations in the samples were measured using cold-vapor AAS. The results were used to examine: (1) overall mass balances; (2) relative distribution in the power plant; (3) equilibrium of Hg species using MALT-2 calculation program; and (4) Hg concentrations in stack emissions. The mass balances estimated in this study were 100, 138 and 89%, respectively, for the coals. Total Hg concentrations in stack gas were 1.113, 0.422 and 0.712 microg(m3N), respectively, for the coals. More than 99.5% of the Hg in the stack emissions were in gaseous form and the proportion in particulate form was extremely low. The relative distribution of Hg in ESP, FGD and Stack ranged from 8.3 to 55.2%, 13.3 to 69.2% and 12.2% to 44.4%, respectively. The results indicated that factors other than the Hg concentration of coals and efficiency of pollution control devices might affect Hg emissions from coal-fired plant. The calculated equilibrium of the distribution of Hg species using the MALT2 program suggest that it is necessary to consider condensation mechanism to interpret the affect of Hg species on the variations of the removal efficiencies of Hg in the ESP.

Journal Article↗
PubMed2000

Initial T-cell activation required for transplant vasculopathy in retransplanted rat cardiac allografts.

BACKGROUND: A precise understanding of immunological mechanisms is needed to prevent transplant vasculopathy. METHODS: The developing process of transplant vasculopathy was investigated by retransplanting rat cardiac allografts and measuring the expressions of 21 different genes inside the retransplanted allografts under nonimmunosuppressive conditions. RESULTS: Significant transplant vasculopathy developed if WKY hearts were grafted to LEW and retransplanted to WKY 5 days after the initial grafting, but it did not in allografts retransplanted 3 days after the initial grafting. The disease did not progress in retransplanted isografts or if nude rats were used as the initial recipients. However, the development of transplant vasculopathy was not affected by changing the second recipients to the F1 progeny of donor x recipient or to nude animals. Among the expressions of 21 different genes observed in allografts at 1, 14, 30, or 60 days after retransplantation, those of T-cell activation-related genes, such as interferon-y and Fas ligand, showed the earliest and the most dramatic difference between 3- and 5-day-retransplanted allografts whereas macrophage/monocyte activation-related genes showed little difference. Furthermore, reverse transcription-polymerase chain reaction analyses of allografts retransplanted to nude animal indicated that T cells of the initial recipient origin survive and remain activated even 60 days after retransplantation. CONCLUSIONS: The T-cell response occurring between 3 and 5 days after grafting was identified as the critical parameter to the disease progression. Once alloreactive T cells enter a graft, they may be able to survive a long period and promote chronic rejection.

Animals↗
PubMed2000

Amelioration of experimental autoimmune uveoretinitis by pretreatment with a pathogenic peptide in liposome and anti-CD40 ligand monoclonal antibody.

We have defined a peptide K2 (ADKDVVVLTSSRTGGV) that corresponds to residues 201-216 of bovine interphotoreceptor retinoid-binding protein and induces experimental autoimmune uveoretinitis (EAU)4 in H-2Ak-carrying mice (H-2Ak mice). In this study, we attempted to ameliorate EAU in the H-2Ak mice without nonspecific suppression of T cell responses. Preceding s.c. administration of liposomes including K2 (liposomal K2) specifically inhibited subsequent generation of T cell response to K2. The same result was obtained with a combination of OVA323-339 peptide and the OVA-specific TCR-transgenic T cells. It was suggested that the inhibition was mainly attributed to peripheral anergy induction of T cells specific for the peptide Ag, although specific cell death might also be involved in the inhibition. Pretreatment with liposomal K2 also considerably abolished IFN-gamma production but not IL-4 production. The specific inhibitory effect of the pretreatment with liposomal peptide was augmented by a simultaneous administration of anti-CD40 ligand (anti-CD40L) mAb. Moreover, it was shown that the pretreatment with liposomal K2 reduced both the incidence and severity of the subsequent K2-induced EAU, and the simultaneous administration of anti-CD40L mAb augmented this preventive effect by liposomal K2. Our findings demonstrate that the s.c. administration of liposomal pathogenic peptide and anti-CD40L mAb can be applied to preventing autoimmune diseases without detrimental nonspecific suppression of T cell responses.

Amino Acid Sequence↗
PubMed2000

One-electron reduction of quinones by the neuronal nitric-oxide synthase reductase domain.

Flavin electron transferases can catalyze one- or two-electron reduction of quinones including bioreductive antitumor quinones. The recombinant neuronal nitric oxide synthase (nNOS) reductase domain, which contains the FAD-FMN prosthetic group pair and calmodulin-binding site, catalyzed aerobic NADPH-oxidation in the presence of the model quinone compound menadione (MD), including antitumor mitomycin C (Mit C) and adriamycin (Adr). Calcium/calmodulin (Ca2+/CaM) stimulated the NADPH oxidation of these quinones. The MD-mediated NADPH oxidation was inhibited in the presence of NAD(P)H:quinone oxidoreductase (QR), but Mit C- and Adr-mediated NADPH oxidations were not. In anaerobic conditions, cytochrome b5 as a scavenger for the menasemiquinone radical (MD*-) was stoichiometrically reduced by the nNOS reductase domain in the presence of MD, but not of QR. These results indicate that the nNOS reductase domain can catalyze a only one-electron reduction of bivalent quinones. In the presence or absence of Ca2+/CaM, the semiquinone radical species were major intermediates observed during the oxidation of the reduced enzyme by MD, but the fully reduced flavin species did not significantly accumulate under these conditions. Air-stable semiquinone did not react rapidly with MD, but the fully reduced species of both flavins, FAD and FMN, could donate one electron to MD. The intramolecular electron transfer between the two flavins is the rate-limiting step in the catalytic cycle [H. Matsuda, T. Iyanagi, Biochim. Biophys. Acta 1473 (1999) 345-355). These data suggest that the enzyme functions between the 1e- <==> 3e- level during one-electron reduction of MD, and that the rates of quinone reductions are stimulated by a rapid electron exchange between the two flavins in the presence of Ca2+/CaM.

Cytochrome P-450 Enzyme System↗
PubMed2000

Importance of donor-derived lymphocytes in the protection of pancreaticoduodenal or islet grafts from recurrent autoimmunity: a role for RT6+NKR-P1+ T cells.

BACKGROUND: A rat pancreas transplantation model with insulin-dependent diabetes mellitus (IDDM) recurrence was established using a Wistar-Furth (WF; RT1u, RT6.2) rat as a donor and diabetes-prone (DP; RT1u, rt6.1 gene carrier) BioBreeding rat as a recipient. Interestingly, NKR-P1+TCRalphabeta+ (NKT) cells have recently been reported to have immunoregulatory functions in preventing autoimmune diabetes. The purpose of this study was to specifically examine the contribution of NKT cells in the prevention of IDDM recurrence. METHODS: Graft survivals with or without anti-intercellular adhesion molecule-1/leukocyte function-associated antigen-1 monoclonal antibodies were examined comparing pancreaticoduodenal (PD) transplantation with islet transplantation or pancreas-alone transplantation excluding duodenum and peripancreatic lymph nodes, in an IDDM recurrent model. The cells of the spleen were analyzed by flow cytometry (including intracellular interleukin (IL)-4 analysis), and serum cytokine levels (IL-4 and interferon-gamma) were determined by enzyme-linked immunosorbent assays (ELISA). RESULTS: Only those DP recipients transplanted with PD grafts with monoclonal antibody treatment were free from IDDM. Flow cytometric analyses of spleen cells showed that NKT cells in them, compared with those in the recurrent DP recipients (mean <7%), increased significantly (13.7+/-3.1% in the total splenic T cells), most of which (85.9+/-4.3%) were derived from the donor (RT6.2+). The absolute number of RT6+NKT cells significantly increased in the nonrecurrent DP recipients, whereas that of RT6-NKT cells was similar with those of the other recurrent DP recipients. These RT6+NKT cells were predominantly CD4+ and showed significantly more expressions of intracellular IL-4 than the other T cells. By ELISA, serum interferon-gamma was not detectable (< 13 pg/ml) in any of the rats. However, IL-4 was detected at 111.6+/-47.8 pg/ml only in the nonrecurrent DP recipients. CONCLUSIONS: Unlike islet or pancreas-alone transplants, NKT cells, especially RT6+NKT cells derived from PD grafts, may have an important immunoregulatory function of preventing IDDM recurrence, involving a Th2 deviation.

ADP Ribose Transferases↗
PubMed2000

Critical contribution of liver natural killer T cells to a murine model of hepatitis.

Natural killer T (NKT) cells constitute a distinct subpopulation of T cells with a unique antigen specificity, prompt effector functions, and an unusual tissue distribution. NKT cells are especially abundant in the liver, but their physiological function in this organ remains unclear. In the present study, we examined the possible contribution of NKT cells to a murine model of hepatitis induced by i.v. injection of Con A. CD1-deficient mice lacking NKT cells were highly resistant to Con A-induced hepatitis. Adoptive transfer of hepatic NKT cells isolated from wild-type mice, but not from FasL-deficient gld mice, sensitized CD1-deficient mice to Con A-induced hepatitis. Furthermore, adoptive transfer of hepatic mononuclear cells from wild-type mice, but not from CD1-deficient mice, sensitized gld mice to Con A-induced hepatitis. Upon Con A administration, hepatic NKT cells rapidly up-regulated cell surface FasL expression and FasL-mediated cytotoxicity. At the same time, NKT cells underwent apoptosis leading to their rapid disappearance in the liver. These results implicated FasL expression on liver NKT cells in the pathogenesis of Con A-induced hepatitis, suggesting a similar pathogenic role in human liver diseases such as autoimmune hepatitis.

Adoptive Transfer↗