Biomedical subjects

M Ishii

Publications and source records attributed to M Ishii.

At least 109 records · Page 6Linked to original sources

PubMed2001

Redistribution of pulmonary blood flow during hypoxic exercise.

Pulmonary blood flow (PBF) distribution was studied at rest and during exercise in rats acclimatized to chronic hypoxia (barometric pressure [PB] 370 Torr for 3 weeks, A rats) and non-acclimatized (NA) littermates. Both A and NA rats exercised in hypoxia (inspired O2 pressure [PIO2] approximately 70 Torr) or in normoxia (PlO2 approximately 145 Torr). PBF distribution was determined using fluorescent-labeled microspheres injected into the right atrium. The lungs were cut into 28 samples to determine relative scatter of specific PBF ([sample fluorescence intensity/sample dry weight)/(total lung fluorescence intensity/total lung dry weight]). Exercise produced redistribution of PBF both in NA and A rats, and this effect was larger in hypoxia than in normoxia, with minimal redistribution occurring during normoxic exercise in NA rats. The pattern of distribution varies considerably among individual animals. As a result of distribution, the previous high flow areas would be overperfused during hypoxic exercise in some rats. The results support the concept that hypoxic pulmonary vasoconstriction is not uniform and suggest that the combination of hypoxia and exercise may lead to overperfusion and capillary leak in some individuals.

Acclimatization↗

PubMed2001

Inflammatory vitiligo in Vogt-Koyanagi-Harada disease.

Vogt-Koyanagi-Harada disease is a rare disease characterized by uveitis, meningitis, dysacusis, alopecia, poliosis, and vitiligo. We describe a 48-year-old patient with Vogt-Koyanagi-Harada disease associated with thin inflammatory raised erythema and plaque-type inflammatory erythema superimposed on vitiligo. Interestingly, inflammatory raised erythema was separated from the perfect vitiligo, and the incomplete vitiligo lay between them initially. Thereafter, incomplete vitiligo became completely depigmented with diminution of inflammatory raised erythema. This is the second case of vitiligo with inflammatory raised borders associated with Vogt-Koyanagi-Harada disease. Our results of immunohistochemical and electron microscopic studies suggested the involvement of T-cell-mediated cytotoxicity and apoptosis in the development of skin lesions.

Humans↗

PubMed2001

Cardiorespiratory exercise capacity and its relation to a new Doppler index in children previously treated with anthracycline.

The purpose of this study was to assess the exercise capacity of patients treated with anthracycline and to evaluate the relation between the exercise capacity and a new Doppler index. The study patients consisted of 70 subjects: 41 healthy subjects and 29 who had been treated with various cumulative doses of anthracycline (range 45 to 873 mg per body surface area). The following conventional echocardiographic parameters were measured: rate-corrected mean velocity of fiber shortening (mVcfc), end-systolic wall stress (ESS), stress-velocity index, and early and late diastolic mitral inflow velocities and their ratio. A new Doppler index, the Tei index, was calculated as the sum of isovolumic contraction time and isovolumic relaxation time divided by the ejection time. Peak oxygen uptake (pVo(2)) and anaerobic threshold (AT) were measured during an upright bicycle exercise test. The pVo(2) and AT in the patient group were significantly lower than those in the control group (pVo(2): 22.0 +/- 3.7 versus 28.5 +/- 7.1 mL/min/kg; AT: 12.7 +/- 1.9 versus 17.3 +/- 4.3 mL/min/kg, respectively; P <.01). There were no significant differences in the mVcfc, ESS, stress-velocity index, E wave, A wave, or E/A wave ratio between the two groups. However, the mean Tei index of the patients was significantly greater than that of the controls (0.41 +/- 0.11 versus 0.33 +/- 0.04, P <.01). The pVo(2) and AT decreased significantly with an increase in the Tei index (r = -0.64 and -0.60, respectively; P <.01). A weak positive correlation was found between the AT and E/A wave ratio (r = 0.54, P <.05). However, no significant correlations were seen between the exercise parameters and the mVcfc, ESS, stress velocity index, or transmitral velocities. Our findings suggest that cardiopulmonary exercise testing revealed an inverse correlation between exercise capacity and the Tei index.

Adolescent↗

PubMed2001

Development of composite cultured oral mucosa utilizing collagen sponge matrix and contracted collagen gel: a preliminary study for clinical applications.

A new type of cultured mucosa was developed as a mucosal substitute. This composite cultured oral mucosa (CCOM) was composed of (1) a lamina propria in which fibroblasts were embedded in contacted collagen gel and honeycomb structured collagen sponge and (2) stratified epithelial cell layers on the surface of the cultured lamina propria. CCOM had a well-stratified and differentiated epithelial cell layer, and its involucrin and laminin expression resembled that of normal oral mucosa. Desmosomes were recognizable with transmission electron microscopic examination. In the lamina propria, contracted collagen gel had pooled away from the sponge wall, leaving a sparse structure inside the collagen sponge. Transplantation of CCOM to nude mice was performed by creating full-thickness wound and then applying CCOM (n = 12). Murine skin allograft (n = 4) and no-graft conditions (n = 5) served as controls. The mice were sacrificed for histological evaluation and assessed for wound contraction 28 days after transplantation. The epithelium of the CCOM-treated group had five to 10 cell layers, and the dermis contained many fibroblasts and a large amount of collagen bundles. The wound contraction of the CCOM-treated group was statistically less than that of the no-graft group. These results indicate that CCOM has barrier functions against various stresses and can induce a fibrovascular ingrowth from the surrounding wound bed, and that CCOM could be applied in a clinical setting.

Animals↗

PubMed2001

A brief sexual barrier intervention for women living with AIDS: acceptability, use, and ethnicity.

Interventions aimed at reducing sexual transmission of human immunodeficiency virus/sexually transmitted diseases (HIV/STDs) have focused primarily on male condom use among seronegative men and women. However, female-controlled sexual barriers (female condoms and vaginal microbicides) offer women living with acquired immunodeficiency syndrome (AIDS) alternative methods to protect themselves and others from disease transmission. A pilot behavioral intervention was conducted to increase sexual barrier use and enhance and assess factors related to acceptability. Participants (N = 178) were drawn from the Stress Management and Relaxation Training with Expressive Supportive Therapy (SMART/EST) Women's Project, a multisite phase III clinical trial for women living with AIDS (Miami, FL; New York City, NY; Newark, NJ). Intervention participants (n = 89) were matched for age and ethnicity with control condition participants (n = 89). Women were African American (52%), Haitian (15%), Hispanic (19%), Caucasian (10%), and other ethnicities (4%). The intervention condition received barrier products (male and female condoms and spermicides based on nonoxynol-9 in the form of vaginal gel, film, and suppositories) during three sessions held over 3 months. Data on barrier use and acceptability were analyzed at baseline and 3 and 9 months postintervention. Use of N-9 spermicides on a trial basis increased significantly by 3 months in the intervention conditions (22%-51%, P <.05). Cultural differences in acceptability were greatest between Haitian women and women in other ethnic groups. Exposure to this pilot behavioral intervention was associated with increased acceptability and use of chemical barriers without decreased use of male condoms.

Acquired Immunodeficiency Syndrome↗

PubMed2001

Correction of the bilateral complete cleft lip: transformation to a unilateral incomplete cleft lip closure.

The complete lip alveolus and cleft palate is the most difficult of all bilateral clefts to treat because of the deformity of and tissue insufficiency in the prolabium. A bilateral concomitant procedure is impractical for treatment of this condition because of the problems that have to be resolved postoperatively, including a short columella, a lack of philtrum, labial horizontal and vertical insufficiency, and vermilion and alveolar vestibulum insufficiency. A two-stage procedure called the transformation method has been developed to circumvent these problems, and the authors present it here. With this method one side is closed completely using the maximum amount of tissue available. Concomitantly, incomplete closure is performed on the other side. The result at the end of the first stage of the procedure is a condition approximating unilateral incomplete closure. The results were obtained from 6 patients who underwent complete bilateral closure and were followed for at least 2 years with satisfactory results.

Child, Preschool↗

PubMed2001

Pleuropericarditis and disseminated intravascular coagulation in ulcerative colitis.

We report a 30-year-old woman with pleuropericarditis, cardiac tamponade, and disseminated intravascular coagulation complicating active ulcerative colitis (UC). Other autoimmune diseases were not present. She responded to pulsed steroid therapy and anticoagulant with resolution of the complication and UC. We reviewed the literature and found 27 cases of pleuropericarditis associated with idiopathic inflammatory bowel disease (IBD). It has been reported that pleuropericarditis associated with IBD responds well to nonsteroidal antiinflammatory drugs, as well as steroids. The causes of cardiac involvement in IBD remain unclear, but the pleuropericarditis must be recognized as a potential extraintestinal manifestation of IBD.

Adult↗

PubMed2001

Angiotensin(1-7) potentiates bradykinin-induced vasodilatation in man.

BACKGROUND: It has been clearly demonstrated that angiotensin(1-7) potentiates the vasodilating effect of bradykinin in isolated vessels of animals. OBJECTIVE: To investigate the interaction between angiotensin(1-7) Ang(1-7) and bradykinin in human forearm resistant vessels of normotensive healthy men in vivo, by the measurement of forearm blood flow using venous occlusion, strain-gauge plethysmography with intra-arterial infusions of peptides in a placebo-controlled, double-blind, cross-over design. METHODS: In eight men, bradykinin was infused intra-arterially twice; placebo, Ang(1-7), or angiotensin II was co-infused with the second infusion. The effect of inhibition of nitric oxide synthase on the interaction between Ang(1-7) and bradykinin was also tested in eight other individuals. The effects of Ang(1-7) were analyzed by analysis of variance (ANOVA) and by the ratios of individually derived areas under the dose-response curves (AUC) of bradykinin, adjusted for changes in the AUCs by repeated infusions of bradykinin with placebo. RESULTS: Ang(1-7) (1000 pmol/min) significantly potentiated the vasodilating effect of bradykinin compared with the effect of saline (P = 0.0471, ANOVA) and in a dose-dependent manner (adjusted AUC ratio [95% confidence interval (CI)] 2.75 (1.72 to 3.78) with 1000 pmol/min, 1.62 (1.31 to 1.93) with 100 pmol/min, and 0.98 (0.80, to 1.09) with 10 pmol/min). This effect was completely abolished by co-infusion of NG-monomethyl-l-arginine [AUC ratio 0.98 (0.90 to 1.04)]. Ang(1-7) did not affect the vasodilating effects of either acetylcholine or sodium nitroprusside. CONCLUSIONS: Ang(1-7) potentiates the vasodilating effect of bradykinin, possibly through a mechanism(s) involving nitric oxide release, in human forearm resistance vessels.

Adult↗

PubMed2001

Targets of transcriptional regulation by transforming growth factor-beta: expression profile analysis using oligonucleotide arrays.

Transforming growth factor-betas (TGF-betas) are potent inhibitors of cell proliferation, and disruption of components of the TGF-beta signaling pathway leads to tumorigenesis. Mutations of transmembrane receptors and Smads mediating intracellular signaling have been reported in various cancers. To identify transcriptional targets of TGF-beta, we conducted an expression profile analysis. HaCaT cells derived from human keratinocytes and highly sensitive to TGF-beta were treated with TGF-beta in the absence or presence of cycloheximide (CHX). mRNAs extracted from the HaCaT cells were used for hybridization of oligonucleotide arrays representing approximately 5600 human genes. TGF-beta increased the expression of PAI-1, junB, p21 cdk inhibitor, Smad7, betaIG-H3, and involucrin that have been reported to be up-regulated by TGF-beta, validating the usefulness of this approach. The induction of betaIG-H3 by TGF-beta was completely abolished by CHX, suggesting that the transcription of betaIG-H3 is not directly regulated by TGF-beta. Unexpectedly, we identified more genes down-regulated by TGF-beta than up-regulated ones. TGF-beta repressed the expression of epithelial specific Ets that may be involved in breast and lung tumorigenesis, which could contribute to tumor suppression by TGF-beta. Among a panel of cell cycle regulators, TGF-beta induced the expression of p21 cdk inhibitor; however, the induction of other cdk inhibitors was not significant in the present study. Taken together, the results suggest that TGF-beta may suppress tumorigenesis through positive and negative regulation of transcription.

Cell Cycle↗

PubMed2001

Simultaneous double or triple coil technique for closure of moderate sized (> or = 3.0 mm) patent ductus arteriosus.

One important complication of coil occlusion of patent ductus arteriosus using the conventional Gianturco coil is migration of coils into peripheral vessels. Especially in patients having relatively larger size ductus, the risk for such complication could be increased. In this regard, a detachable coil may have some technical benefits in performing coil occlusion and reducing the incidence of complications such as migration of coil. Based on our clinical experiences, we describe the clinical efficacy of a simultaneous double or triple coil occlusion technique using the Cook detachable coil system to close the ductus arteriosus, especially in patients whose ductus diameter more than 3.0 mm.

Adolescent↗

PubMed2001

Chemical structure of a novel aminophospholipid from Hydrogenobacter thermophilus strain TK-6.

The phospholipid composition of Hydrogenobacter thermophilus strain TK-6, an obligately chemolithoautotrophic, extremely thermophilic hydrogen bacterium, was analyzed. Two of four phospholipids detected from the strain were assumed to be phosphatidylinositol and phosphatidylglycerol. An aminophospholipid named PX, whose content among the phospholipids was 65%, was found to have a novel chemical structure by analysis of the dilyso form with nuclear magnetic resonance and fast atom bombardment-mass spectrometry (FAB-MS) and by analysis of the intact PX with FAB-MS as 1,2-diacyl-3-O-(phospho-2'-O-(1'-amino)-2',3',4',5'-pentanetetrol)-sn-glycerol. Structurally similar phospholipids have been identified in Methanospirillum hungatei, Methanolacinia paynteri, and Methanogenium cariaci, which all belong to the Archaea.

Amino Sugars↗

PubMed2001

Effects of hypercapnia and hypocapnia on [Ca2+]i mobilization in human pulmonary artery endothelial cells.

The hydrogen ion is an important factor in the alteration of vascular tone in pulmonary circulation. Endothelial cells modulate vascular tone by producing vasoactive substances such as prostacyclin (PGI2) through a process depending on intracellular Ca2+ concentration ([Ca2+]i). We studied the influence of CO2-related pH changes on [Ca2+]i and PGI2 production in human pulmonary artery endothelial cells (HPAECs). Hypercapnic acidosis appreciably increased [Ca2+]i from 112 +/- 24 to 157 +/- 38 nmol/l. Intracellular acidification at a normal extracellular pH increased [Ca2+]i comparable to that observed during hypercapnic acidosis. The hypercapnia-induced increase in [Ca2+]i was unchanged by the removal of Ca2+ from the extracellular medium or by the depletion of thapsigargin-sensitive intracellular Ca2+ stores. Hypercapnic acidosis may thus release Ca2+ from pH-sensitive but thapsigargin-insensitive intracellular Ca2+ stores. Hypocapnic alkalosis caused a fivefold increase in [Ca2+]i compared with hypercapnic acidosis. Intracellular alkalinization at a normal extracellular pH did not affect [Ca2+]i. The hypocapnia-evoked increase in [Ca2+]i was decreased from 242 +/- 56 to 50 +/- 32 nmol/l by the removal of extracellular Ca2+. The main mechanism affecting the hypocapnia-dependent [Ca2+]i increase was thought to be the augmented influx of extracellular Ca2+ mediated by extracellular alkalosis. Hypercapnic acidosis caused little change in PGI2 production, but hypocapnic alkalosis increased it markedly. In conclusion, both hypercapnic acidosis and hypocapnic alkalosis increase [Ca2+]i in HPAECs, but the mechanisms and pathophysiological significance of these increases may differ qualitatively.

Acidosis, Respiratory↗

PubMed2001

Linear constraints on weight representation for generalized learning of multilayer networks.

In this article, we present a technique to improve the generalization ability of multilayer neural networks. The proposed method introduces linear constraints on weight representation based on the invariance natures of training targets. We propose a learning method that introduces effective linear constraints into an error function as a penalty term. Furthermore, introduction of such constraints leads to reduction of the VC dimension of neural networks. We show bounds on the VC dimension of the neural networks with such constraints. Finally, we demonstrate the effectiveness of the proposed method by some experiments.

Algorithms↗

PubMed2001

Dissecting receptor-mediated Ca2+ influx pathways: TRP channels and their native counterparts.

Cellular stimulation from the surrounding extracellular environment via receptors and other pathways evoke activation of Ca2+-permeable cation channels that form essential signaling pathways in controlling biological responses. An important clue to understand the molecular mechanisms underlying these cation channels (tentatively termed as receptor-mediated cation channels (RMCC)) was first provided through molecular studies of the transient receptor potential (trp) protein (TRP), which controls light-induced depolarization in Drosophila photoreceptor cells. Use of the genetic information and recombinant expression technique lead to the discovery of numerous mammalian TRP homologues revealing novel RMCCs. In this review, we focus on the dramatic progress in the molecular investigation of RMCC in mammalian systems. The recent findings should provide powerful tools for the development of novel pharmaceutical targets.

Animals↗

PubMed2001

Carboxy-PTIO increases the tetrahydrobiopterin level in mouse brain microvascular endothelial cells.

The aim of the present study was to characterize the increase in tetrahydrobiopterin (BH4), which is a cofactor for nitric oxide synthase (NOS), by carboxy-PTIO, a scavenger of nitric oxide (NO), in vascular endothelial cells. BH4 level was determined by oxidation under acidic conditions as biopterin. Addition of lipopolysaccharide (LPS) to endothelial cells increased mRNA levels of inducible NOS (iNOS) and GTP-cyclohydrolase I (GTPCH), which is a rate-limiting enzyme for BH4 synthesis, and the biopterin level. NOS inhibitors, NO-donors and L-arginine, a substrate of NOS, did not affect the increase in the biopterin level induced by LPS, suggesting that BH4 synthesis is unlikely to be modulated by NO produced by iNOS during LPS treatment. However, carboxy-PTIO increased the biopterin level in the absence and the presence of LPS. Carboxy-PTIO did not affect the expression of GTPCH mRNA level. Moreover, 2,4-diamino-6-hydroxypyrimidine, an inhibitor of GTPCH, inhibited only about 30% of the carboxy-PTIO-induced increase in the biopterin level. Whereas, N-acetylserotonin, an inhibitor of sepiapterin reductase, strongly inhibited the increase in biopterin level. Carboxy-PTIO inhibited the accumulation of pterin, a decomposition product of BH4 in endothelial cells. These findings suggest that carboxy-PTIO accumulates BH4 under basal and LPS-treated conditions in vascular endothelial cells due to both inhibition of the decomposition of BH4 to pterin and activation of the salvage pathway of BH4 synthesis via sepiapterin reductase.

Alcohol Oxidoreductases↗

PubMed2001

Denaturing gradient gel electrophoresis analyses of microbial community from field-scale composter.

The diversity of microbial community during the decomposition of waste in a field-scale composter (Hazaka system) was investigated by denaturing gradient gel electrophoresis (DGGE). The composter operates at a high temperature through a self-heating system, creating a thermophilic (60-76 degrees C) stage during the initial phase and a mesophilic (45 degrees C) stage towards the later phase of the composting period. The pH of the system (pH 7.75-8.10) did not vary significantly during the process while moisture content was reduced from 48.8% to 25.1%. DGGE and 16S rDNA analyses showed that the following genera were found throughout the process: Propionibacterium sp., Methylobacterium sp., Pseudomonas sp., and Bradyrhizobium sp. Different Bacillus spp. thrive at the thermophilic or the mesophilic stage while Clostridium sp. was only found at the initial phase of the process. Staphylococcus sp. and Caulobacter sp. or Brevundimonas sp. existed during the later phase of the composting period.

Journal Article↗

PubMed2001

Analyses of microbial community within a composter operated using household garbage with special reference to the addition of soybean oil.

A commercially available composter was operated using fixed composition of garbage with or without the addition of soybean oil. The composter was operated without adding seed microorganisms or bulking materials. Microflora within the composter were analyzed by denaturing gradient gel electrophoresis (DGGE) in the case of oil addition, or by 16/18 S rRNA gene sequencing of the isolated microorganisms in the case of no oil addition. The results showed that, irrespective of the addition of oil, the bacteria identified were all gram positive, and that lactobacilli seemed to be the key microorganisms. Based on the results, suitable microflora for use in a household composter are discussed.

Journal Article↗

PubMed2001

Characterization of a microorganism isolated from the effluent of hydrogen fermentation by microflora.

The hydrogen production yield from glucose by an isolate was investigated and compared to that by microflora. The isolate, Thermoanaerobacterium thermosaccharolyticum KU001, from the microflora demonstrated approximately 2.4 mol/mol-glucose of hydrogen production with acetate/butyrate formation in an artificial medium. The fermentation pattern was similar to that observed for the hydrogen fermentation of wastewater by the microflora. A PCR-DGGE analysis of the bacterial 16S rDNA detected T. thermosaccharolyticum in the microflora with strong intensity of the characteristic 16S rDNA band, although the microflora was enriched from an artificial medium. These results imply that T. thermosaccharolyticum could be a predominant species of the microflora that is involved in hydrogen-producing acetate/butyrate fermentation. The nitrogen source in the medium affected the carbohydrate metabolism of KU001, and caused a change in hydrogen yield.

Journal Article↗