Biomedical subjects

Toshiaki Ikeda

Publications and source records attributed to Toshiaki Ikeda.

9 recordsLinked to original sources

PubMed2006

High fidelity self-sorting assembling of meso-cinchomeronimide appended meso-meso linked Zn(II) diporphyrins.

In noncoordinating solvents, meso-cinchomeronimide appended Zn(II) porphyrin 2 forms a cyclic trimer, while diporphyrins 7 exhibit high-fidelity self-sorting assembling to form discrete cyclic trimer, tetramer, and pentamer with large association constants from 7(in-in), 7(in)(-)(out), and 7(out-out), respectively, through almost perfect discrimination of enantiomeric and conformational differences of the meso-cinchomeronimide substituents. In the latter self-sorting processes, the dihedral angles dictated by the two pyridyl nitrogen atoms control the size of the aggregates; the trimer from 7(in-in), the tetarmer from 7(in)(-)(out), and the pentamer from 7(out-out). Cyclic structures of (2)(3) and (R-7(out-out))(5) have been determined by single-crystal X-ray diffraction analysis.

Biomimetic Materials↗

PubMed2006

Physiological response to superantigen-adsorbing hemoperfusion in toxin-concentration-controlled septic swine.

BACKGROUND/AIMS: Superantigens are suspected of being potent initiators of gram-positive sepsis, and new therapies for superantigen elimination are required. The effects of hemoadsorption with a superantigen-adsorbing device (SAAD) were evaluated in septic swine. METHODS: Toxic shock syndrome toxin-1 (TSST-1) was infused, and blood concentration was maintained at the clinical level for 6 h. Endotoxin was then infused to induce lethal shock. All animals were hemoperfused with SAAD or a control column for 8 h and changes in pathological parameters and mortality were examined. RESULTS: Animals perfused with SAAD had a highly significant (p < 0.01) survival advantage compared with control groups at 24 h after initiation of the TSST-1 infusion. SAAD also suppressed the increase in the arteriovenous shunt ratio and decrease of partial arterial oxygen pressure at 6 h after TSST-1 infusion initiation. CONCLUSION: We suggest that there is a potential application of SAAD in treating superantigen-induced respiratory dysfunction and sepsis.

Adsorption↗

PubMed2006

A multicenter, prospective validation of disseminated intravascular coagulation diagnostic criteria for critically ill patients: comparing current criteria.

OBJECTIVES: To validate scoring algorithm criteria established by the Japanese Association for Acute Medicine (JAAM) for disseminated intravascular coagulation (DIC) and to evaluate its diagnostic property by comparing the two leading scoring systems for DIC, from the Japanese Ministry of Health and Welfare (JMHW) and International Society on Thrombosis and Haemostasis (ISTH). DESIGN: Prospective, multicenter study during a 3-month period. SETTING: General critical care center in a tertiary care hospital. PATIENTS: Two hundred seventy-three patients with platelet counts<150x109/L were enrolled. INTERVENTION: None. MEASUREMENTS AND MAIN RESULTS: The JAAM, JMHW, and ISTH DIC scoring algorithms were prospectively applied within 12 hrs of patients meeting the inclusion criteria (day 0) to days 1-3, by global coagulation tests. The numbers of systemic inflammatory response syndrome (SIRS) criteria and Sequential Organ Failure Assessment (SOFA) scores were determined simultaneously. Mortality associated with any cause was also assessed 28 days after the enrollment. All global coagulation tests and SIRS criteria adopted in the JAAM criteria and their cutoff points were validated with use of SOFA scores and mortality rate. DIC diagnostic rate of the JAAM DIC scoring system was significantly higher than that of the other two criteria (p<.001). The JAAM DIC algorithm was the most sensitive for early diagnosis of DIC (p<.001). PATIENTS who fulfilled the JAAM DIC criteria included almost all those whose DIC was diagnosed by the JMHW and ISTH scoring systems. The JAAM DIC scores showed significant correlation with SOFA scores ([rho]=0.499; p<.001). SOFA score and mortality rate worsened in accordance with an increase in the JAAM DIC score. Fibrinogen criteria had little effect in predicting outcome for the DIC patients, and a total score of 4 points in the JAAM scoring system without fibrinogen was closely related to poor prognosis. According to the results, we revised the JAAM criteria by excluding fibrinogen and confirmed that the DIC diagnostic properties of original criteria remained unchanged in the revised JAAM criteria. CONCLUSIONS: The JAAM scoring system has an acceptable property for the diagnosis of DIC. The scoring system identified most of the patients diagnosed by the JMHW and ISTH criteria. Revised JAAM DIC criteria preserved all properties of the original criteria for DIC diagnosis. The revised scoring system can be useful for selecting DIC patients for early treatment in a critical care setting.

Algorithms↗

PubMed2005

Superantigen-induced multiple organ dysfunction in a toxin-concentration-controlled and sequential parameter-monitored swine sepsis model.

OBJECTIVE: In order to examine the biological activity of low-dose and continuously infused superantigen, and to establish a superantigen-induced multiple organ dysfunction animal model, several pathophysiological parameters were sequentially monitored in a toxin-concentration-controlled pig model. METHODS: Anesthetized, mechanically ventilated and Swan-Ganz thermodilution catheter-inserted pigs were treated with toxic shock syndrome toxin-1 (TSST-1) by infusion at 2 microg/kg/h for 5 h. Monitoring was performed for both the infusion period and a subsequent 1-h post-infusion period. RESULTS: The serum concentration of TSST-1 was controlled so as to elevate it to a level over 1000 pg/mL within 1 h of initiation of infusion, and then gradually increased further and reached a plateau of about 2500 pg/mL at 4h after initiation. The animals showed a significant increase in cardiac output, the intrapulmonary arteriovenous shunt ratio, and infiltration of white blood cells into the lung. Although the observed increase in pulmonary vascular resistance was not statistically significant, it did correlate with the reduction in white blood cell counts. CONCLUSION: The superantigen TSST-1 plays an important role in the pathogenesis of Gram-positive bacterial sepsis by inducing multiple organ dysfunction. Thus, this model provides the first tool to allow the simultaneous examination of the serum toxin levels and other organ parameters in a time-course manner.

Animals↗

PubMed2005

Multicenter prospective study of procalcitonin as an indicator of sepsis.

The clinical significance of serum procalcitonin (PCT) for discriminating between bacterial infectious disease and nonbacterial infectious disease (such as systemic inflammatory response syndrome (SIRS)), was compared with the significance of endotoxin, beta-D: -glucan, interleukin (IL)-6, and C-reactive protein (CRP) in a multicenter prospective study. The concentrations of PCT in patients with systemic bacterial infection and those with localized bacterial infection were significantly higher than the concentrations in patients with nonbacterial infection or noninfectious diseases. In addition, PCT, endotoxin, IL-6, and CRP concentrations were significantly higher in patients with bacterial infectious disease than in those with nonbacterial infectious disease (P<0.001, P<0.005, P<0.001, and P<0.001, respectively). The cutoff value of PCT for the discrimination of bacterial and nonbacterial infectious diseases was determined to be 0.5 ng/ml, which was associated with a sensitivity of 64.4% and specificity of 86.0%. Areas under the receiver operating characteristic curves (POCs) were 0.84 for PCT, 0.60 for endotoxin, 0.77 for IL-6, and 0.78 for CRP in the combined group of patients with bacterial infectious disease and those with nonbacterial infectious disease, and the area under the ROC for PCT was significantly higher than that for endotoxin (P<0.001). In patients diagnosed with bacteremia based on clinical findings, the positive rate of diagnosis with PCT was 70.2%, while that of blood culture was 42.6%. PCT is thus essential for discriminating bacterial infection from SIRS, and is superior in this respect to conventional serum markers and blood culture.

Biomarkers↗

PubMed2004

Clinical evaluation of PMX-DHP for hypercytokinemia caused by septic multiple organ failure.

Endotoxin-adsorbing fibers have been applied to treat septic shock patients. The limitations of endotoxin hemoadsorption therapy (PMX-DHP) and the optimal time to start PMX-DHP were examined in patients with septic multiple organ failure with hypercytokinemia (interleukin-6 = 1000 pg/mL). Subjects were separated into those who survived more than 28 days after the start of PMX-DHP therapy (S group) and those who did not (N-S group). Severity of symptoms and background factors, blood biochemical parameters, hemodynamic parameters, PaO(2)/FiO(2), pathogens, endotoxin, cytokines, and vascular endothelial cell function-related markers were examined before and after PMX-DHP. Number of days from onset of shock (or symptom development) to PMX-DHP initiation was longer in the N-S group than in the S group. These results suggest that PMX-DHP could save more lives in patients with septic multiple organ failure with IL-6 = 1000 pg/mL when applied early after the onset of shock.

APACHE↗

PubMed2003

Changes in circulating levels of calcitonin gene-related peptide and nitric oxide metabolites in septic patients during direct hemoperfusion with polymyxin B-immobilized fiber.

BACKGROUND/AIMS: This study evaluated the mechanism of hemodynamic improvement in polymyxin B-immobilized fiber (PMX) treatment. METHODS: Fifteen septic patients with endotoxemia and/or gram negative infection were treated with PMX. Plasma concentrations of calcitonin gene-related peptide (CGRP) and nitric oxide metabolites were measured. RESULTS: CGRP and nitric oxide metabolites before treatment were significantly higher than in healthy controls. CGRP had a significantly inverse correlation with diastolic blood pressure and a positive correlation with the Septic Severity Score and the number of failed organs. Systolic and diastolic blood pressure and systemic vascular resistance index increased significantly both immediately after and 24 h after PMX treatment. CGRP decreased significantly 24 h after the treatment. In contrast, there were no significant changes in nitric oxide metabolites. CONCLUSION: PMX treatment improved hemodynamic parameters in septic patients, and CGRP increased with increasing severity of sepsis. We conclude that a decrease in CGRP levels may be related to hemodynamic improvement resulting from PMX treatments.

Aged↗

PubMed2003

Colloid osmotic pressure (COP) can be a good indicator of occurrence of vasospasm following subarachnoid hemorrhage (SAH).

BACKGROUND: The aim of this study was to evaluate the value of measurement of colloid osmotic pressure (COP) directly concerned with cerebral vasospasm following subarachnoid hemorrhage (SAH). MATERIAL/METHODS: The subjects were 20 patients who received clipping operation within 48 hours after onset. We conducted a two weeks monitoring of COP measured directly by osmometer and evaluated serum concentrations of albumin at the same time. We divided the patients into Group A (angiographical vasospasm +) and Group B (spasm -) according to the angiographical findings. The differences of the data between the groups were analyzed by ANOVA test (p<0.05). Furthermore, the correlations between the serum concentrations of albumin and COP levels were estimated. RESULTS: Vasospasm was angiographically confirmed in 10 of the 20 patients. Significant decrease of COP levels was observed from day 7 until day 11 and significant decrease of albumin was observed on day 6 and from day 8 until day 11 in the Group A. We did not observe any significant change of COP and albumin levels in the Group B. A liner analysis was performed and a significant correlation was determined between the COP levels and albumin in the Group A, but we did not observe significant correlation between them in the Group B. CONCLUSIONS: These results showed that a significant decrease of COP levels indicate the occurrence of cerebral vasospasm. We concluded that COP measurement could be a useful monitor of the occurrence of vasospasm following SAH.

Adult↗

PubMed2002

Hemoadsorption in critical care.

This paper concerns the results of endotoxin hemoadsorption therapy using a PMX column in patients with perforative peritonitis complicated by multiple organ failure. The subjects were 31 patients aged 68 +/- 12 years. When systolic arterial pressure decreased to less than 90 mm Hg, endotoxin hemoadsorption was initiated and continued for 2 h. At the completion of endotoxin hemoadsorption, systolic arterial pressure, diastolic arterial pressure, and mean arterial pressure were significantly increased. Platelet count decreased to less than 50,000/mm(3) in 30% of patients. As for cytokines and vascular endothelial cell function markers, interleukin-6 and plasminogen activator inhibitor-1 significantly decreased. These results suggest favorable effects of endotoxin hemoadsorption on the hemodynamic and pathophysiological conditions in patients with septic shock although attention should be given to the decrease in platelet count.

Adsorption↗