Koichi Akiyama

IV Immunoglobulin for Acute Lung Injury and Bacteremia in Pseudomonas aeruginosa Pneumonia.

Objectives:Virulent and multidrug-resistant Pseudomonas aeruginosa causes a lethal pneumonia, especially in patients who are artificially ventilated. It has been reported that the virulence mechanism used by P. aeruginosa, which is linked to acute lung injury, is strongly associated with the type III secretion system, and specific antibodies targeting this system have shown a protective effect in both experimental and clinical settings. We investigated the effect of administering IV immunoglobulins on P. aeruginosa pneumonia, including its associated bacteremia and mortality, although focusing especially on type III secretion system–associated P. aeruginosa virulence. Design:Prospective randomized and controlled animal study. Setting:University laboratory. Subjects:Male ICR mice. Interventions:Mice were infected intratracheally with a lethal dose of the virulent P. aeruginosa PA103 strain. IV immunoglobulin administration was examined in three different settings: 1) premixed; 2) pre-IV, prophylactic administration before bacterial infection; and 3) post-IV, therapeutic administration after bacterial infection. The effect of specific antigen titer depletion of IV immunoglobulins was also examined. Measurements and Main Results:Survival and body temperature were monitored for 24 hours. Bacteremia, cytokine concentration, myeloperoxidase activity, WBC counts in the blood, and lung bacterial load were evaluated. Survival improved significantly in mice that received IV immunoglobulins (p < 0.05). Lung edema, lung bacteriologic load, and bacteremia decreased significantly in the IV immunoglobulin–treated mice (p < 0.05). The mechanism of protection was associated with the presence of antibodies against both PcrV and some bacterial surface antigens in the IV immunoglobulins. Conclusions:IV immunoglobulin administration had a significantly protective effect against lethal infection from virulent P. aeruginosa. Prophylactic IV immunoglobulin administration at the highest dose was comparable with that achieved by administrating a specific anti-PcrV polyclonal IgG into the mice. The mechanism of protection is likely to involve the synergic action of anti-PcrV titers and antibodies against some surface antigen(s) that block the type III secretion system–associated virulence of P. aeruginosa.

Efficacy comparison of adjuvants in PcrV vaccine againstPseudomonas aeruginosapneumonia: Vaccines againstP. aeruginosapneumonia

Vaccination against the type III secretion system of P. aeruginosa is a potential prophylactic strategy for reducing the incidence and improving the poor prognosis of P. aeruginosa pneumonia. In this study, the efficacies of three different adjuvants, Freunds adjuvant (FA), aluminum hydroxide (alum) and CpG oligodeoxynucleotide (ODN), were examined from the viewpoint of inducing PcrV‐specific immunity against virulent P. aeruginosa. Mice that had been immunized intraperitoneally with recombinant PcrV formulated with one of the above adjuvants were challenged intratracheally with a lethal dose of P. aeruginosa. The PcrV–FA immunized group attained a survival rate of 91%, whereas the survival rates of the PcrV–alum and PcrV–CpG groups were 73% and 64%, respectively. In terms of hypothermia recovery after bacterial instillation, PcrV–alum was the most protective, followed by PcrV–FA and PcrV–CpG. The lung edema index was lower in the PcrV–CpG vaccination group than in the other groups. PcrV–alum immunization was associated with the greatest decrease in myeloperoxidase in infected lungs, and also decreased the number of lung bacteria to a similar number as in the PcrV–FA group. There was less neutrophil recruitment in the lungs of mice vaccinated with PcrV–alum or PcrV–CpG than in those of mice vaccinated with PcrV–FA or PcrV alone. Overall, in terms of mouse survival the PcrV–CpG vaccine, which could be a relatively safe next‐generation vaccine, showed a comparable effect to the PcrV–alum vaccine.

Flow-dynamics assessment of mitral-valve surgery by intraoperative vector flow mapping

OBJECTIVES We assessed vortex patterns and energy loss in left ventricular flow in patients who underwent mitral valve repair or replacement with bioprosthetic valves. METHODS Vector flow mapping was performed before and after the procedure in 15 and 17 patients who underwent repair and replacement, respectively. The preprocedure mitral-septal angle was measured in all patients. Relationships between vortex patterns or energy loss change (ELC) and annuloplasty ring or bioprosthetic valve sizes or the effect of mitral leaflet resection in the repair group were statistically analysed. RESULTS Normal vortex patterns were observed in 13 and 1 patients who underwent repair and replacement, respectively. Abnormal vortex patterns were observed in 2 and 16 patients who underwent repair and replacement, respectively. ELC was significantly higher in the replacement group (196.6 ± 180.8) than in the repair group (71.9 ± 43.9). In the repair group, preoperative mitral-septal angles in patients with normal vortex patterns (79.2° ± 3.4°) were significantly larger than those in patients with abnormal vortex patterns (67.5° ± 3.5°). No significant differences were observed in the effects of annuloplasty ring and bioprosthetic valve sizes on vortex patterns and ELC, and in the effect of mitral valve resection (80.4 ± 56.3) and respect (without leaflet resection) (53.8 ± 28.4) on ELC in the repair group. CONCLUSIONS Mitral valve replacement alters the intraventricular vortex pattern and increases flow energy loss. A small mitral-septal angle is a risk factor for abnormal vortex patterns after mitral valve repair surgery.

The prophylactic effects of human IgG derived from sera containing high anti-PcrV titers against pneumonia-causing Pseudomonas aeruginosa

ABSTRACT The PcrV cap structure of the type III secretory apparatus of Pseudomonas aeruginosa is a vaccine target. Human immunoglobulin G (IgG) molecules extracted from sera containing high or low anti-PcrV titers were tested for their effects against P. aeruginosa pneumonia in a mouse model. Among 198 volunteers, we selected the top 10 high anti-PcrV titer sera and the bottom 10 low anti-PcrV titer sera and extracted the IgG fraction from each serum sample. First, we examined the effects of the IgG against virulent P. aeruginosa. A lethal dose of P. aeruginosa premixed with saline, low titer human IgG, high titer human IgG, or rabbit-derived polyclonal anti-PcrV IgG was intratracheally administered into the lungs of mice, and their survival and lung inflammation were evaluated for 24 h. The high anti-PcrV titer human IgG had a prophylactic effect. Next, the prophylactic effects of intravenous administration of extracted and pooled high or low anti-PcrV titer human IgG were examined. Here, prophylactic intravenous administration of pooled high anti-PcrV titer human IgG, which showed binding capacity to P. aeruginosa PcrV, was more effective than the administration of its low titer pooled equivalent, and the measured physiological and inflammatory parameters correlated with the anti-PcrV titer levels. This result indirectly implies that high anti-PcrV titers in blood can help to protect against virulent P. aeruginosa infections. In addition, the IgG fractions from such high titer sera have potential to be a source of specific intravenous immunoglobulin products for passive vaccination against virulent P. aeruginosa infections.

Pseudomonas aeruginosa Type III Secretory Toxin ExoU and Its Predicted Homologs

Pseudomonas aeruginosa ExoU, a type III secretory toxin and major virulence factor with patatin-like phospholipase activity, is responsible for acute lung injury and sepsis in immunocompromised patients. Through use of a recently updated bacterial genome database, protein sequences predicted to be homologous to Ps. aeruginosa ExoU were identified in 17 other Pseudomonas species (Ps. fluorescens, Ps. lundensis, Ps. weihenstephanensis, Ps. marginalis, Ps. rhodesiae, Ps. synxantha, Ps. libanensis, Ps. extremaustralis, Ps. veronii, Ps. simiae, Ps. trivialis, Ps. tolaasii, Ps. orientalis, Ps. taetrolens, Ps. syringae, Ps. viridiflava, and Ps. cannabina) and 8 Gram-negative bacteria from three other genera (Photorhabdus, Aeromonas, and Paludibacterium). In the alignment of the predicted primary amino acid sequences used for the phylogenetic analyses, both highly conserved and nonconserved parts of the toxin were discovered among the various species. Further comparative studies of the predicted ExoU homologs should provide us with more detailed information about the unique characteristics of the Ps. aeruginosa ExoU toxin.

Flow Energy Loss Evaluation in a Systolic Anterior Motion Case After the Ross Procedure

Flow drag has attracted attention as the dominant hydrodynamic force causing systolic anterior motion (SAM). SAM begins when the flow velocity in the outflow tract is low, precluding the Venturi effect. It also may begin during isovolumic systole before the aortic valve opens. In this study, the authors presented a case using the Ross procedure during which SAM developed and was difficult to relieve. Left ventricular blood flow and flow energy loss were analyzed using real-time vector flow mapping, a novel flow visualization technology. Vector flow mapping revealed that both early systolic flow impacting the

Epidemiological analysis of serum anti-Pseudomonas aeruginosa PcrV titers in adults.

Of the various virulence mechanisms of the opportunistic pathogen Pseudomonas aeruginosa, the type III secretion system (TTSS) has been characterized as a major factor associated with acute lung injury, bacteremia and mortality. In addition, PcrV, a component protein of the TTSS, has been characterized as a protective antigen against infection with P. aeruginosa. This study comprised an epidemiological analysis of serum anti‐PcrV titers in a cohort of Japanese adults. From April 2012 to March 2013, serum anti‐PcrV titers of 198 volunteer participants undergoing anesthesia for scheduled surgeries were measured. The median, minimum and maximum serum anti‐PcrV titers among the 198 participants were 4.09 nM, 1.01 nM and 113.81 nM, respectively. The maximum peaks in the histogram were within the anti‐PcrV 2.00–4.99 nM titer range; values for 115 participants (58.1%) were within this range. Anti‐PcrV titers were more than approximately three‐fold greater (>12 nM) than the median value in 21 participants (10.6%). Ten‐year interval age increases, history of treatment for traffic trauma, and a history of past surgery each showed statistically significant associations with higher anti‐PcrV titers (i.e., >10 nM) than did the other factors assessed by binomial analysis. This study revealed a considerable variation in anti‐PcrV titers in adult subjects without any obvious histories of infection with P. aeruginosa.

MITRAL VALVE REPLACEMENT IMPAIRS LEFT VENTRICULAR BLOOD FLOW

According to our experimental analysis, blood flow in left ventricle change after Mitral Valve Replacement. We attempted to investigate blood flow and energy loss (EL) in patients who were scheduled for mitral valve surgery using novel analysis software Vector Flow Mapping (VFM). Patients with

Effective evaluation of arterial pulse waveform analysis by two-dimensional stroke volume variation–stroke volume index plots

Arterial pulse waveform analysis (APWA) with a semi-invasive cardiac output monitoring device is popular in perioperative hemodynamic and fluid management. However, in APWA, evaluation of hemodynamic data is not well discussed. In this study, we analyzed how we visually interpret hemodynamic data, including stroke volume variation (SVV) and stroke volume (SV) derived from APWA. We performed arithmetic estimation of the SVV–SV relationship and applied measured values to this estimation. We then collected measured values in six anesthesia cases, including three liver transplantations and three other types of surgeries, to apply them to this SVV–SVI (stroke volume variation index) plot. Arithmetic analysis showed that the relationship between SVV and SV can be drawn as hyperbolic curves. Plotting SVV-SV values in the semi-logarithmic scale showed linear correlations, and the slopes of the linear regression lines theoretically represented average mean cardiac contractility. In clinical measurements in APWA, plotting SVV and SVI values in the linear scale and the semi-logarithmic scale showed the correlations represented by hyperbolic curves and linear regression lines. The plots approximately shifted on the rectangular hyperbolic curves, depending on blood loss and blood transfusion. Arithmetic estimation is close to real measurement of the SVV–SV interaction in hyperbolic curves. In APWA, using SVV as an index of preload and the cardiac index or SVI derived from arterial pressure-based cardiac output as an index of cardiac function, is likely to be appropriate for categorizing hemodynamic stages as a substitute for Forrester subsets.

Visualization of suppressed intraventricular flow by constrictive pericarditis

Here,we report a case of constrictive pericarditis inwhichwe can assess the intraventricular blood flow and energetic parameters. A 49-year-old man with a diagnosis of constrictive pericarditis was referred to our institution for pericardiectomy. He complained of back and neck pain with progressive development of dyspnea (NYHA class IV) and generalized edema. The bloodflow,flowenergy loss, and kinetic energy of the left ventricle were assessed by vector flowmapping application (Hitachi Aloka Medical, Tokyo, Japan) in the ME long-axis (LAX) view by transesophageal echocardiography (TEE) [1,2]. Before the procedure, blood flowed from the apex toward the basal posterior wall, and a counterclockwise vortex was formed during isovolumic contraction (Fig. 1-A, B) [2]. After the aortic valve was