Frequency of bacterial contamination of platelet concentrates before and after introduction of diversion method in Japan.

BACKGROUND: Bacterial contamination of platelet concentrates (PCs) is the major infectious risk in transfusion medicine. To evaluate the necessity of implementing novel strategies for the reduction of bacterial contamination, it is necessary to establish a precise contamination frequency in PCs. STUDY DESIGN AND METHODS: The frequency of bacterial contamination in PCs issued by the Japanese Red Cross was determined using expired PCs before and after the implementation of the diversion method. The culture method was designed such that it yields the least possibility of false-negative results: platelet specimens were sampled after at least 4 days of storage and the inoculum volume was 10 mL for both aerobic and anaerobic bottle cultures. RESULTS: Of the 21,786 PCs cultured, 36 (0.17%) were confirmed to be bacterially contaminated before the implementation of the diversion method. After its implementation, the number of contaminated PCs decreased to 11 of 21,783 (0.05%) with a reduction rate of 71% and the number of contaminations of clinical importance was 4 (0.018%) excluding PCs positive for Propionibacterium acnes. The frequency of contamination by bacteria presumed to originate from donors' blood did not decrease. CONCLUSION: The effect of the diversion method on the frequency of bacterial contamination is robust. The low incidence of septic reactions after PC transfusion in Japan in spite of the contamination frequency being comparable to those in Western countries and the noninstitution of culture screening suggests the importance of a short shelf life (72 hr) for PCs introduced in Japan.

The effect of direct hemoperfusion with a polymyxin B-immobilized fiber column (DHP-PMX therapy) on pulmonary ischemia-reperfusion injury in a canine model.

UNLABELLED: This study evaluates the effectiveness of direct hemoperfusion with a polymyxin B-immobilized fiber column (DHP-PMX therapy) on warm ischemia-reperfusion injury of the lung using a canine mode. MATERIALS AND METHODS: Ten adult mongrel dogs weighing 13-16 kg were used. After a left thoracotomy, the left pulmonary artery and vein were clamped. The left main bronchus was also clamped and then divided, and complete ischemia of the left lung was maintained for 3 h. The left main bronchus was re-anastomosed before reperfusion of the left lung. The right pulmonary artery was ligated immediately after reperfusion of the left lung. The dogs were divided into two groups: the DHP-PMX group (n = 5, DHP-PMX was performed for 120 min, from 30 min before reperfusion to 90 min after reperfusion) and the control group (n = 5). The body temperature of the animals was maintained at 36 degrees C-37 degrees C during the experiment. The PaO2/FiO2 (P/F ratio), AaDO2, and lt-pulmonary vascular resistance (PVR) were measured at 30, 60, 120, 180, and 240 min after reperfusion in both groups, and the two groups were compared. The water content of the lung tissues and histopathology was also analyzed. RESULTS: The P/F ratio decreased remarkably after reperfusion in the control group, and was significantly (p < .05) lower than that in the PMX-DHF group until 240 min after reperfusion. The AaDO2 was significantly (p < .05) lower in the DHP-PMX group than in the control group at 30, 60, and 120 min after reperfusion. The lt-PVR level differed significantly (p < .05) between the two groups until 240 min after reperfusion. The water content in the control group was significantly (p < .05) higher than that in the DHP-PMX group at 240 min after reperfusion. Lung tissues at 120 and 240 min after reperfusion were better preserved pathologically in the DHP-PMX group. CONCLUSION: DHP-PMX therapy reduced warm ischemia-reperfusion injury in the lung using a canine model.

Effect of atrial natriuretic peptide on ischemia-reperfusion injury in a porcine total hepatic vascular exclusion model.

AIM: To evaluate the effect of ANP on warm I/R injury in a porcine THVE model. METHODS: Miniature pigs (mini-pigs) weighing 16-24 kg were observed for 120 min after reperfusion following 120 min of THVE. The animals were divided into two groups. ANP (0.1 mug/kg per min) was administered to the ANP group (n = 7), and vehicle was administered to the control group (n = 7). Either vehicle or ANP was intravenously administered from 30 min before the THVE to the end of the experiment. Arterial blood was collected to measure AST, LDH, and TNF-alpha. Hepatic tissue blood flow (HTBF) was also measured. Liver specimens were harvested for p38 MAPK analysis and histological study. Those results were compared between the two groups. RESULTS: The AST and LDH levels were lower in the ANP group than in the control group; the AST levels were significantly different between the two groups (60 min: 568.7 +/- 113.3 vs 321.6 +/- 60.1, P = 0.038 < 0.05, 120 min: 673.6 +/- 148.2 vs 281.1 +/- 44.8, P = 0.004 < 0.01). No significant difference was observed in the TNF-alpha levels between the two groups. HTBF was higher in the ANP group, but the difference was not significant. A significantly higher level of phosphorylated p38 MAPK was observed in the ANP group compared to the control group (0 min: 2.92 +/- 1.1 vs 6.38 +/- 1.1, P = 0.011 < 0.05). Histological tissue damage was milder in the ANP group than in the control group. CONCLUSION: Our results show that ANP has a protective role in I/R injury with p38 MAPK activation in a porcine THVE model.

Effect of the free radical scavenger MCI-186 on pulmonary ischemia-reperfusion injury in dogs.

BACKGROUND: Free radical scavengers and superoxide dismutase have been found to protect against cerebral ischemic damage, and it was suggested that oxygen free radicals contribute to ischemia-reperfusion injury induced by cerebral ischemic damage. MCI-186 (3-methyl-1-phenyl-2-pyrazolin-5-one) is a potent scavenger and inhibitor of hydroxyl radicals and protective agent of peroxidative injury. The purpose of this study was to evaluate the effects of MCI-186 on pulmonary ischemia-reperfusion injury in a simulated transplanted lung model. METHODS: Fourteen dogs were divided into two groups (n = 7 each). In the MCI group, MCI-186 was continuously administered at 3 mg/kg/hour intravenously (IV) from 30 minutes before reperfusion until 30 minutes after reperfusion (total administration time 1 hour). Vehicle was administered in the control group. Warm ischemia was induced for 3 hours by clamping the left pulmonary artery and veins. Simultaneously, the left stem bronchus was bisected and then anastomosed before reperfusion. The right pulmonary artery was ligated 15 minutes after reperfusion, and the right stem bronchus was then bisected. RESULTS: The respiratory gas exchange, hemodynamic changes, wet-to-dry weight ratio (WDR) and malondialdehyde (MDA) concentration in the tissue were significantly improved (p < 0.05) in the MCI group. The histologic damage was more severe in the control group and polymorphonuclear neutrophil (PMN) infiltration was reduced in the MCI group. CONCLUSION: MCI-186 has a protective effect on pulmonary ischemia-reperfusion injury through the inhibition of lipid peroxidation.

Effects of a free radical scavenger, MCI-186, on ischemia-reperfusion injury during extended liver resection in dogs.

BACKGROUND/AIMS: In liver surgery, total clamping of the portal triad (Pringle's procedure) is commonly used, and this sometimes causes liver failure. This study evaluated the effects of a free radical scavenger, MCI-186, on ischemia-reperfusion injury during liver resection in dogs. METHODOLOGY: The experimental animals were divided into two groups. In the MCI group (n = 6), MCI-186 (6mg/kg/h) was administered twice, through a catheter placed in the right hepatic vein: the first time was from 0.5 hours before the onset of ischemia until ischemia by partial inflow occlusion, and the second was from 0.5-hours before reperfusion until reperfusion. In the control group (n = 6), vehicle (physiological saline) was administered in the same manner. RESULTS: The serum AST, ALT, and LDH levels were significantly (P < 0.05) lower in the MCI group than in the control group. Hepatic tissue blood flow 0.5 hours after reperfusion was significantly (P < 0.05) higher in the MCI group than in the control group. Histological tissue damage was mild, and tissue MDA levels were significantly (P < 0.05) lower in the MCI group than in the control group. CONCLUSIONS: MCI-186 ameliorates the ischemia-reperfusion injury caused by Pringle's procedure during extended liver resection.

Support adapter for radiofrequency ablation probe: experimental study.

BACKGROUND: The purpose of the present study was to experimentally evaluate a new support adapter, which was created in order to insure a more complete contact between the ablation probe and a beating heart. METHODS: Support sleeve adapters for the Cobra Cooled probe were fashioned using a semi-rigid plastic. Forty epicardial radiofrequency ablation (RFA) lesions were created on both atria under the condition of a beating heart in six pigs weighing 26-30 kg. A Cobra Cooled surgical probe was used with continuous internal irrigation of a saline solution (500 mL/h). The ablation temperature was fixed at 80 degrees C and the duration of the RFA in each case was 20, 30 and 60 s. RESULTS: A support adapter ensured a more complete epicardial contact between the probe and a beating heart. An RFA probe supported by the adapter delivered greater power to the tissue. The histopathological transmural coagulation was obtained in 82% and 72% in RFA lesions with and without the adaptor, respectively. CONCLUSION: A new adapter was effective in the epicardial RFA under the condition of a beating heart.

Epicardial radiofrequency ablation on a beating heart: an experimental study.

PURPOSE: The effect of epicardial radiofrequency ablation (RFA) during normal heart beating was experimentally studied in order to establish safe and effective procedures for RFA. METHODS: Seven pigs weighing approximately 30 to 50 kg were used in this study. Fifty-one epicardial RFA lesions were created on both atria using a Cobra Cooled probe with continuous internal irrigation of a saline solution. The ablation temperature was fixed at 80 degrees C and the duration of the RFA in each case was 20, 30, 60 and 120 seconds. RESULTS: There was significant positive correlation between the right and left atria in wall thickness. Transmural coagulation was obtained in 69% of the total specimens, which decreased according to the increase of wall thickness especially over 3 mm. Transmural coagulation was seen in 64% of the specimens after RFA of less than 30 seconds, and 86% after ablation of >or=60 seconds. Occurence of 90% or deeper coagulation was higher in the right atrium than in the left one (97% vs. 78%). Right atrial rupture occurred in a region of 1 mm in thickness after ablation of 60 seconds. CONCLUSION: Further technical improvements associated with new instruments are indispensable to complete epicardial RFA procedures on a beating heart.

Measuring platelet aggregation to estimate small intestinal ischemia-reperfusion injury.

BACKGROUND: The success of intestinal transplantation is affected by the extreme susceptibility of the small bowel to ischemia-reperfusion (I/R) injury. Currently, there is no quick, convenient method to estimate the extent of small bowel I/R injury. Although histological evaluation is reliable and accurate, it takes too long to allow favorable intervention in I/R injury. I/R causes the production of arachidonic acid products, oxygen free radicals, cytokines, and nitric oxide, which affect platelet function. OBJECTIVE: This study determined whether measuring platelet aggregation is useful for evaluating small bowel I/R injury. METHODS: Eighteen mongrel dogs were divided into three groups. In group A both the superior mesenteric artery (SMA) and vein (SMV) were occluded for 120 min. In group B the SMA was occluded for 60 min. Group C underwent a sham operation. Platelet aggregation was measured using a whole blood aggregometer (WBA analyzer), which readily handles small samples. Histological examination was performed. The correlation between platelet aggregation and histology was analyzed. RESULTS: Platelet aggregation was similar in all groups before reperfusion. After reperfusion, platelet aggregation was significantly lower in group A than in groups B and C (P < 0.05), and mucosal damage was most severe in group A (P < 0.05). After 1 and 3 h of reperfusion, there was a significant negative correlation between platelet aggregation and histological damage. CONCLUSIONS: Measuring platelet aggregation is rapid, easy, and useful for evaluating small bowel I/R injury.

Effect of modified ultrafiltration on inflammatory mediators, coagulation factors, and other proteins in blood after an extracorporeal circuit.

Modified ultrafiltration (MUF) is a technique able to remove the excess body fluid and inflammatory mediators associated with the use of a cardiopulmonary bypass (CPB). It has been shown to reduce morbidity after cardiac operations in children. Application of MUF after adult cardiac operations has also been suggested being associated with a lower prevalence of early morbidity. However, the relationship between the concentration of mediators in the blood and postoperative morbidity remains yet to be proved. In this study, changes of various chemical mediators in the filtrate and blood before and after MUF have been evaluated in adult patients. Significant reductions of blood levels of inflammatory cytokines were not observed after MUF. On the other hand, MUF significantly elevated hematocrit, number of red cells, concentrations of albumine, coagulation Factor VII and X, platelet factor (PF)-4, and antithrombin (AT-) III.