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Biomedical subjects

N Yoshida

Publications and source records attributed to N Yoshida.

At least 361 records · Page 20Linked to original sources
PubMed1993

Importance of ischemic preconditioning and collateral circulation for left ventricular functional recovery in patients with successful intracoronary thrombolysis for acute myocardial infarction.

We studied the effects of myocardial ischemic preconditioning and preexistent collateral circulation on the preservation of left ventricular function in 30 patients who had successful intracoronary thrombolysis within 6 hours after the onset of a first acute anterior myocardial infarction. The existence of ischemic preconditioning was defined as the episode of recurrent ischemic chest pain within 4 hours before the onset of acute myocardial infarction. In 16 patients with ischemic preconditioning (group A), the left ventricular ejection fraction during the convalescence of myocardial infarction was 57% +/- 11% (mean +/- SD); regional wall motion in the infarct area was 13% +/- 9%. In 14 patients without ischemic preconditioning (group B), the left ventricular ejection fraction and regional wall motion in the infarct area were 46% +/- 9% and 5% +/- 9% (both p < 0.05 vs group A). Moreover, among group A patients, seven patients having a well-developed collateral circulation during the acute stage of myocardial infarction showed a more prominent improvement in regional wall motion in the infarct area compared with nine patients having poor or no collateral circulation (18% +/- 8% vs 9% +/- 7%, p < 0.05). These data indicate that ischemic preconditioning is effective for the preservation of left ventricular function in patients with successful intracoronary thrombolysis and that preexistent coronary collateral circulation potentiates this favorable effect of ischemic preconditioning.

Adult↗
PubMed1993

Mechanisms involved in Helicobacter pylori-induced inflammation.

BACKGROUND: Helicobacter pylori infection is associated with mucosal inflammation. The aims of the present study were to assess whether a water extract of H. pylori promotes neutrophil (polymorphonuclear leukocyte [PMN]) adherence to endothelial cells and define the molecular basis of this adhesive interaction. METHODS: Intravital microscopy was used to study leukocyte adhesive interactions in rat mesenteric venules in situ. PMN-endothelial cell adhesive interactions were studied in vitro using human PMNs and monolayers of human umbilical vein endothelial cells (HUVEC). RESULTS: In vivo, superfusion of rat mesentery with the H. pylori extract increased leukocyte adhesion and emigration in venules. In vitro, adhesion of human PMNs to HUVEC was increased by the H. pylori extract in a concentration-dependent manner. Pretreatment of HUVEC alone with H. pylori extract had no effect on PMN adherence, whereas pretreatment of PMN alone significantly increased their adherence to HUVEC. The extract-induced adhesion was significantly diminished by monoclonal antibodies (MAb) directed against either CD11a, CD11b, or CD18 on neutrophils, and by MAbs against intercellular adhesion molecule-1 (ICAM-1), but not E- or P-selectin, on endothelial cells. CONCLUSIONS: These studies suggest that products of H. pylori elicit gastrointestinal inflammation by promoting PMN adhesion to endothelial cells via CD11a/CD18- and CD11b/CD18-dependent interactions with ICAM-1.

Animals↗
PubMed1993

Molecular determinants of aspirin-induced neutrophil adherence to endothelial cells.

BACKGROUND: Previous studies indicate that aspirin can promote neutrophil adhesion to venular endothelium in vivo. The objectives of the present study were (1) to identify the leukocyte and endothelial cell surface glycoproteins that mediate this adhesive interaction and (2) to assess the role of lipoxygenase products, prostanoids, and platelet activating factor in aspirin-induced neutrophil adhesion. METHODS: Human neutrophils (polymorphonuclear leukocytes [PMN]) were added to confluent monolayers of human umbilical vein endothelial cells (HUVEC) and coincubated with or without aspirin (30, 150, or 300 micrograms/mL). RESULTS: Aspirin increased neutrophil adherence to HUVEC in a dose-dependent manner. Pretreatment of HUVEC with aspirin had no effect on PMN adherence whereas pretreatment of PMN significantly increased adherence to HUVEC. Incubation of neutrophils with aspirin increased surface expression of CD11b and CD18 on neutrophils. The aspirin-induced increase in PMN adherence to HUVEC was significantly reduced by monoclonal antibodies against CD18, CD11b, CD11a, and intercellular adhesion molecule 1. Aspirin-induced neutrophil adhesion was diminished by treatment with either a lipoxygenase inhibitor or a leukotriene B4 (LTB4) receptor antagonist. CONCLUSIONS: These studies indicate that aspirin promotes neutrophil adherence to endothelium via CD11a/CD18- and CD11b/CD18-dependent interactions with intercellular adhesion molecule 1; the adhesion response is partially mediated by leukotriene B4.

Adult↗
PubMed1993

Assessment of fetal growth and serum hCG titers after in vitro fertilization and embryo transfer.

Fetal growth in early pregnancy was estimated by transvaginal ultrasonic measurement and serum hCG measurement in 13 women who became pregnant through in vitro fertilization and embryo transfer treatment. The first day of observation of a gestational sac (GS) or fetal heart movement (FHM) of over 120 beats/min confirmed the pregnancy. There were 6 or 7 days difference in GS or FHM confirmation within 20 or 30 days after insemination, although statistical deviations were very small (GS: 21.3 +/- 1.8, FHM: 29.5 +/- 1.8 days after insemination, mean +/- S.D.). Increases in crown-rump length (CRL) and serum hCG were used as indicators of fetal growth. There was a good correlation between CRL or serum hCG and days after insemination (CRL: r = 0.95, n = 55; hCG: r = 0.96, n = 77), and individual cases had almost the same velocity of CRL growth and serum hCG elevation as each regression line. This data suggests that each embryo has a different growth velocity from the fertilized oocyte until the first clinical confirmation of pregnancy.

Adult↗
PubMed1993

Percutaneous transluminal angioplasty for the M2 portion vasospasm following SAH: development of the new microballoon and report of cases.

A new silicone microballoon was developed for the percutaneous transluminal angioplasty of smaller intracranial vessels, such as A1, A2 and M2. This balloon was 0.5 x 2.0 mm in the deflated condition and became 2.2 x 6.5 mm inflated with 0.02 mL of fluid, and its bursting pressure was 2 atm. Two illustrative cases are presented. The first case was not treated in the M2 distribution. The second case of vasospasm of the left M2 portion was successfully treated with this new balloon, with prompt improvement of the neurological condition and cerebral circulation. The usefulness of our microballoon in treating a patient with vasospasm of small intracranial arteries is discussed.

Angioplasty, Balloon↗
PubMed1993

Mucin-like glycoproteins linked to the membrane by glycosylphosphatidylinositol anchor are the major acceptors of sialic acid in a reaction catalyzed by trans-sialidase in metacyclic forms of Trypanosoma cruzi.

We have previously shown that 35- and 50-kDa glycoconjugates of cultured metacyclic trypomastigotes participate in the attachment of parasites to mammalian cells. Here we show that when metacyclic trypomastigotes are incubated with [3H]sialyllactose, most of the sialic acid is transferred to these 35/50-kDa molecules in a reaction catalyzed by a parasite transsialidase. The sialic acid is incorporated in oligosaccharides of about 10 glucose units in size that are released from the glycoconjugate by mild alkaline hydrolysis. Compositional analysis reveals that the 35/50-kDa molecules are highly glycosylated proteins rich in threonine, galactose, N-acetyl-glucosamine and sialic acid. These glycoproteins can be labeled in vivo with [3H]palmitate, and the labeled fatty acid is released by glycosylphosphatidylinositol specific phospholipases C. This result, associated with the fact that they contain mannose, ethanolamine, myo-inositol, and lipid, indicate that these glycoproteins are anchored to the membrane by glycosylphosphatidylinositol. During cell invasion, these molecules appear to be capped and locally released by the parasite.

Amino Acids↗
PubMed1993

Relation between collateral channel filling and flow grade in recipient coronary arteries in patients with stable effort angina.

OBJECTIVES: The purpose of the present study was to elucidate the relation between the extent of perfusion of the ischemia-related coronary artery and the degree of visualization of the collateral circulation to the ischemic area. BACKGROUND: Because it is difficult to accurately assess coronary stenosis severity with standard angiographic techniques, the inclusion of flow grade in recipient coronary arteries would provide an additional perspective concerning the effect of the progression of atherosclerotic obstructive disease on the development of collateral circulation. METHODS: The coronary arteriograms of 54 consecutive patients with chronic effort angina without prior myocardial infarction were examined. Patients were classified into four groups according to the extent of perfusion of the ischemia-related coronary artery (Thrombolysis in Myocardial Infarction [TIMI] grade 0 to 3). The degree of angiographically demonstrable collateral circulation was also classified into four grades (collateral index 0 to 3). RESULTS: Eighteen patients had TIMI grade 0, 6 had grade 1, 13 had grade 2 and 17 had grade 3 perfusion. The collateral indexes of TIMI 0, 1, 2 and 3 groups were 2.7 +/- 0.7 (mean +/- SEM), 2.2 +/- 0.6, 1.2 +/- 1.1 and 0.4 +/- 0.9, respectively (p < 0.01 vs. TIMI 0, p < 0.05 vs. TIMI 1). CONCLUSIONS: These findings indicate that all patients with chronic effort angina have the potential for collateral development as a result of coronary artery narrowing, and the functional state of well developed collateral vessels may be primarily determined by the pressure gradient across the collateral network.

Aged↗
PubMed1993

Effect of barbiturate therapy on phenytoin pharmacokinetics.

OBJECTIVE: To evaluate the effect of high-dose pentobarbital therapy on phenytoin pharmacokinetics. DESIGN: A prospective, clinical study. SETTING: The intensive care unit of a university hospital. PATIENTS: Ten adult patients with cerebral lesions requiring anticonvulsants and control of intracranial pressure. INTERVENTIONS: Each patient received phenytoin sufficient to maintain a plasma concentration at 15 micrograms/mL (60 mumol/L) both before and after barbiturate therapy. Plasma concentrations of total phenytoin, unbound phenytoin, and the major metabolite of phenytoin, 5-(p-hydroxyphenyl)-5-phenylhydantoin, were measured, and pharmacokinetic variables obtained before and after barbiturate therapy were compared. MEASUREMENTS AND MAIN RESULTS: Plasma concentrations of total phenytoin remained within the therapeutic range during the 12-hr period preceding barbiturate therapy. After barbiturate therapy, plasma concentrations of both total and unbound phenytoin were significantly less than those concentrations before barbiturate therapy. For total phenytoin, maximum metabolic velocity was increased by 62% (1.09 +/- 0.62 to 1.77 +/- 0.52 mg/L/hr, 1.20 +/- 0.68 to 1.95 +/- 0.57 nmol/L/sec, p < .05), and area under the plasma concentration-time curve (0 to infinity) and mean residence time were each decreased by 73% (32.5 +/- 20.0 to 8.7 +/- 3.1 min.mg/mL, 2.14 +/- 1.25 to 0.57 +/- 0.19 sec.mmol/L, p < .01, and 135,000 +/- 69,000 to 37,000 +/- 11,000 secs, p < .005, respectively) after barbiturate therapy. The plasma concentration of the principal metabolite of phenytoin, 5-(p-hydroxyphenyl)-5-phenylhydantoin, was significantly increased after barbiturate therapy. CONCLUSIONS: Phenytoin metabolism is increased by barbiturate therapy, and supplemental doses of phenytoin and frequent drug monitoring may be required after barbiturate therapy.

Adult↗
PubMed1993

The 35/50 kDa surface antigen of Trypanosoma cruzi metacyclic trypomastigotes, an adhesion molecule involved in host cell invasion.

We have previously shown that monoclonal antibodies directed to the 90 kDa glycoprotein and the 35/50 kDa glycoconjugate, present on the surface of Trypanosoma cruzi metacyclic trypomastigotes, inhibited host cell invasion. Here we investigated whether these molecules could be the ligands for the target cell receptor. Binding assays were performed by incubating Vero cells with sonicated parasite extract. Detection of bound parasite components was carried out by using monoclonal antibodies (MoAbs) IG7 and 10D8, which recognize the 90 kDa and the 35/50 kDa antigens respectively. These experiments revealed that the 35/50 kDa glycoconjugate of metacyclic forms, but not the 1G7-reactive antigen, binds to Vero cells. The purified 35/50 kDa antigen bound to Vero cells and inhibited the entry of metacyclic forms in a dose-dependent manner. Although to a lesser extent, an immunologically related 35/50 kDa antigen of non-infective epimastigotes also bound to Vero cells but it was unable to inhibit parasite penetration at a concentration (100 micrograms/ml) in which metacyclic antigen exhibited more than 60% inhibition. All these data suggest that the metacyclic 35/50 kDa surface glycoconjugate is a ligand to the host cell in the process of T. cruzi invasion.

Animals↗
PubMed1993

Differential expression of CR3, Fc epsilon RII and Fc gamma RIII on polymorphonuclear leukocytes in gingival crevicular fluid.

Polymorphonuclear leukocytes (PMNLs) are the most numerous cell population among the cellular infiltrates in gingival crevicular fluid (GCF) and play important roles in the host-defensive system in the gingival crevices. We determined the percentage of neutrophils, eosinophils and basophils in total PMNLs by light microscopic observation using Randolph-methylene blue staining, then assessed flow cytometric differences in the expression of CR3, Fc gamma RIII, Fc epsilon RII, LFA-1 alpha, and LFA-1 beta on PMNL in GCF and peripheral blood (PB) from 21 patients with adult periodontitis (AP) and 13 healthy donors. Percentages of basophils and eosinophils were higher in GCF than in PB. In both AP patients and healthy subjects, expression of CR3 and Fc epsilon RII was higher while Fc gamma RIII was lower in GCF than in PB. The statistical analysis showed that the expressions of Fc gamma RIII and Fc epsilon RII on GCF PMNLs were lower in AP patients than in healthy subjects. Expressions of LFA-1 alpha and beta on GCF were similar to those on PB PMNLs. PB PMNLs stimulated in vitro with Porphyromonas gingivalis culture supernatant and fMLP displayed an expression pattern of CR3, Fc gamma RIII and Fc epsilon RII on GCF PMNLs. However, C5a and IL-1 failed to induce changes in Fc gamma RIII and Fc epsilon RII. The results indicate that GCF neutrophils are activated, present enhanced adhesion and a decreased IgG-binding ability which would reflect that they are at the terminal stage of activation, and that GCF contains a larger eosinophil fraction than in PB. Moreover, these GCF eosinophils appear to be activated.

Adult↗
PubMed1993

Characterization of a cDNA clone encoding the carboxy-terminal domain of a 90-kilodalton surface antigen of Trypanosoma cruzi metacyclic trypomastigotes.

We have cloned and sequenced a cDNA for a metacyclic trypomastigote-specific glycoprotein with a molecular mass of 90 kDa, termed MTS-gp90. By immunoblotting, antibodies to the MTS-gp90 recombinant protein reacted exclusively with a 90-kDa antigen of metacyclic trypomastigotes. The insert of the MTS-gp90 cDNA clone strongly hybridized with a single 3.0-kb mRNA of metacyclic forms, whereas the hybridization signal with epimastigote mRNA was weak and those with RNAs from other developmental stages were negative, indicating that transcription of the MTS-gp90 gene is developmentally regulated. A series of experiments showed that the MTS-gp90 gene is present in multiple copies in the Trypanosoma cruzi genome, arranged in a nontandem manner, and that there are at least 40 copies of the gene per haploid genome. Sequence analysis of recombinant MTS-gp90 revealed 40 to 60% identity at the amino acid level with members of a family of mammalian stage-specific, 85-kDa surface antigens of T. cruzi. However, there are considerable differences in the amino acid compositions outside the homology region.

Amino Acid Sequence↗
PubMed1993

Involvement of the stage-specific 82-kilodalton adhesion molecule of Trypanosoma cruzi metacyclic trypomastigotes in host cell invasion.

This study provides several pieces of evidence indicating that 3F6-Ag, identified by monoclonal antibody (MAb) 3F6 as a stage-specific glycoprotein of approximately 82 kDa on the surface of metacyclic trypomastigotes of different Trypanosoma cruzi strains, promotes the entry of parasites into host cells through a ligand-receptor type interaction. First, invasion of Vero cells by metacyclic trypomastigotes of both CL and Tulahuen strains was significantly inhibited by MAb 3F6 or its Fab fragments. Second, purified 3F6-Ag bound to Vero cells in a dose-dependent and saturable fashion. Third, soluble 3F6-Ag reduced the infection of Vero cells by metacyclic forms of CL and Tulahuen strains by 90 to 97 and 50%, respectively. Unrelated proteins, as well as extracellular matrix components, such as heparan sulfate and collagen, had no effect. Our studies also show that in the Tulahuen strain, 10D8-Ag, a 35/50-kDa glycoprotein identified by MAb 10D8, participates in target cell invasion, confirming previous observations, but the variant form of 10D8-Ag expressed by highly invasive CL strain metacyclic trypomastigotes appears to be irrelevant. Overall, our results indicate that the surface components of T. cruzi metacyclic trypomastigotes involved in the process of host cell penetration are developmentally regulated molecules, such as 3F6-Ag and 10D8-Ag, that have no counterpart in blood- or tissue culture-derived trypomastigotes.

Animals↗
PubMed1993

Low dose radiation-induced adaptive survival response in mouse spleen T-lymphocytes in vivo.

Induction of an adaptive survival response in B6C3F1 mice exposed to whole-body irradiation by low doses of X-rays (priming exposure) then to high doses of X-rays (challenge exposure) was examined. The adaptive survival response was determined by comparing the cloning efficiency of low dose-irradiated spleen T-lymphocytes to that of unprimed controls. Maximal expression of the adaptive survival response induced by exposure to low doses of X-rays occurred 7 hours after the priming exposure. The optimal low dose range for the induction of the adaptive survival response was 0.05-0.1 Gy. Thus, low dose X-irradiation induces the adaptive response in spleen T-lymphocytes of B6C3F1 mice as assessed by survival. The duration of this response is short, and there is an optimal low dose range. The Dq value for the primed cells was somewhat larger than that for the unprimed ones. Low dose exposure may enhance the capacity of spleen cells for repair during priming.

Adaptation, Physiological↗
PubMed1993

[Purification of human neutrophil collagenase, establishment of its monoclonal antibodies and application to gingival crevicular neutrophils].

In order to investigate the role of neutrophil collagenase in the periodontal disease, human neutrophil collagenase was purified and two monoclonal antibodies against this enzyme were obtained. This enzyme was purified by four step-affinity chromatography: heparin-aminocellurofine, gelatin Sepharose 4B, collagen-Sepharose and collagenase inhibitor column chromatographies. To produce the monoclonal antibody against the enzyme, the Balb/c mouse was immunized and its spleen cells were fused with the mouse myeloma cells. Two monoclonal antibodies to the enzyme, 2F3 (IgG1) and 3F12 (IgG1), which recognized a conformational structure of the enzyme apart from its catalytic site were obtained. Both antibodies were monospecific to leukocyte collagenase and did not cross-react with the other metalloproteinases such as leukocyte gelatinase, skin fibroblast collagenase, gelatinase and stromelysin. Using these monoclonal antibodies, collagenase was stained granularly in gingival crevicular neutrophils.

Animals↗
PubMed1993

Pharmacological effects of the new gastroprokinetic agent mosapride citrate and its metabolites in experimental animals.

The pharmacological effects of the metabolites M1 and M2 of mosapride citrate ((+/-)-4-amino-5-chloro-2-ethoxy-N-[[4-(4-fluorobenzyl)-2-morpholi nyl] methyl]benzamide citrate, AS-4370, CAS 112885-42-4), a gastroprokinetic agent with serotonin 5-HT4 receptor agonist property, were compared with those of mosapride. In isolated guinea-pig ileum treated with phenoxybenzamine, the metabolites M1 and M2 enhanced electrically-evoked contractions with EC50 values of 1.2 x 10(-7) mol/l and 1.0 x 10(-6) mol/l, respectively. The metabolite M1 was twice less potent than that of mosapride. When administered intravenously, the metabolite M1 enhanced gastric emptying of a semisolid meal in mice and rats; the potency was 3 times less than that of mosapride in mice and almost equal to that of mosapride in rats. When administered orally, the metabolite M1 enhanced gastric emptying of a semisolid meal in mice and rats, and also enhanced gastric emptying of a resin pellet meal in rats. The potency of metabolite M1 was 10 times less than that of mosapride in rats, although it was equal to that of mosapride in mice. In these experiments, the metabolite M2 was far less active. In addition to these gastroprokinetic properties, the metabolite M1 possessed a potent 5-HT3 receptor antagonist property. The metabolite M1 antagonized the 2-methyl-5-HT-induced bradycardia in anesthetized rats with an ED50 value of 10.5 micrograms/kg, i.v., and inhibited the cisplatin-induced emesis in ferrets with a potency approximately 25 times that of mosapride. These results suggest that the metabolites M1 and M2 of mosapride do not play a crucial role in the gastroprokinetic effect of mosapride.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

[Study of washout rate in patients with chronic renal failure by dipyridamole 201Tl myocardial scintigraphy--comparison with hypertrophic cardiomyopathy].

Fourteen patients with chronic renal failure (CRF) were studied by dipyridamole 201Tl myocardial scintigraphy. In this study, patients with coronary heart disease were excluded by clinical findings. 201Tl SPECT was performed at 8 min after injection of dipyridamole (0.56 mg/kg) and at a 3-hr delayed interval, and washout rates (WR) were calculated. Because UCG showed left ventricular hypertrophy (thickness; 13 +/ 2 mm) in CRF, the WR values were compared with those of hypertrophic cardiomyopathy (HCM) (n = 9). In CRF, an average WR was 54.2 +/- 6.8% and was significantly higher than that in normal (46.2 +/- 9.1%, p < 0.05, n = 9), though WR in HCM was significantly low (26.9 +/- 11.4%, p < 0.01). Hematocrit value was 24.5 +/- 3.2% in CRF and was significantly lower than that in normal (37.8 +/- 3.6%, p < 0.001). On the other hands, hemoconcentration was observed in HCM (hematocrit; 44.6 +/- 3.6%, p < 0.001). WR in CRF, HCM and normal had significant correlation with hematocrit values (r = -0.796, p < 0.001). These results suggest that anemia or hemoconcentration may affect coronary blood flow and WR, and this should be considered when diagnosing coronary heart disease in CRF or HCM.

Cardiomyopathy, Hypertrophic↗
PubMed1993

[Effects of high doses of beclomethasone dipropionate in bronchial asthma].

To evaluate the clinical efficacy of high dose inhaled steroids, we examined the effects of standard doses (400 micrograms/day) and high doses (800 micrograms/day) of inhaled beclomethasone dipropionate (BDP, Becotide Inhaler), and the dose for regular use (800 micrograms/day) of salbutamol (Salb. Asmidon Air) on pulmonary function, bronchial hyperresponsiveness and asthma attack score. The subjects were 17 out-patients with mild or moderate bronchial asthma who were not receiving any anti-allergics or steroids. The patients were randomly allocated into three groups i.e., Group I: BDP 400 micrograms/day, Group II: BDP 800 micrograms/day and Group III: Salb. 800 micrograms/day. The administration period was 8 weeks. Pulmonary function test were performed and bronchial hyperresponsiveness was examined before and after the 8 weeks of treatment and attack scores were recorded during this period. It was found that inhalations of 400 micrograms/day and 800 micrograms/day BDP improved FEV1.0% value, peak flow, F-V curve, Dmin. and SGrs/Grs cont. Particularly, inhalation of 800 micrograms/day of BDP significantly improved these values and reduced attack scores in the early stages of the 8 week treatment. In contrast, there was a trend for inhalation of Salbutamol to enhance bronchial hyperresponsiveness and not to improve pulmonary function and asthma attack score. In conclusion, 800 micrograms/day of inhaled BDP is considered to be useful in the treatment of mild or moderate bronchial asthma.

Adult↗