How Training Tools Physically Linking Soccer Players Improve Interpersonal Coordination.

Interpersonal coordination is an important skill for promoting collective behavior in team sports. This study tested the impact of two types of tools in facilitating triadic coordination. 16 males aged under 12 years were divided into four groups with similar skill levels and average ages. Each group performed a three-versus-one ball passing task under three conditions: a one-elastic-band tool linking the three players, a three-elastic-bands tool linking the three players, and without a tool linking the three players. The dependent variables were ball passing frequency, frequency and amplitude of inner angles of the triangle formed by the players, and duration of the synchronized patterns of the inner angles. The results show that neither tool increased ball-passing frequency or the duration of synchronized patterns. However, both tools increased the frequency of inner angles, and the three-elastic-bands tool decreased the amplitude of inner angles. From these results, we conclude that elastic-band tools affect spatial and temporal triadic formation by means of haptic and visual information. Specifically, compared with the one-elastic-band tool, the three-elastic-bands tool stabilizes the triadic spatial formation. We also explore the implications for how these tools can be used in practice.

Social forces for team coordination in ball possession game.

Team coordination is a basic human behavioral trait observed in many real-life communities. To promote teamwork, it is important to cultivate social skills that elicit team coordination. In the present work, we consider which social skills are indispensable for individuals performing a ball possession game in soccer. We develop a simple social force model that describes the synchronized motion of offensive players. Comparing the simulation results with experimental observations, we uncovered that the cooperative social force, a measure of perception skill, has the most important role in reproducing the harmonized collective motion of experienced players in the task. We further developed an experimental tool that facilitates real players' perceptions of interpersonal distance, revealing that the tool improves novice players' motions as if the cooperative social force were imposed.

A case of abdominal aortic aneurysm with horseshoe kidney.

A 69-year-old male who had an abdominal aortic aneurysm with horseshoe kidney is reported. Preoperative 3-dimensional computed tomoangiography (3DCTA) images confirmed two accessory renal arteries diverging from the aneurysm to the isthmus. We operated on the abdominal aortic aneurysm using the left retroperitoneal approach, which provided excellent exposure of the aneurysm without dividing the renal isthmus. This exposure showed us the accessory arteries, so we could easily recognize these arteries visualized by 3DCTA, and we could reconstruct the larger one of two accessory arteries. Preoperative 3DCTA was very useful for the operation of the abdominal aortic aneurysm with horseshoe kidney. The postoperative course was uneventful.

Verapamil and nitroglycerin improves the patency rate of radial artery grafts.

The best way to prevent spasm of the radial artery is still under investigation. We retrospectively compared the effectiveness of topical verapamil-nitroglycerin with papaverine in preventing graft spasm in 215 patients who underwent isolated conventional coronary artery bypass using a radial artery. Postoperative angiographic data were successfully collected in 116 patients. Perioperative radial artery graft spasm was observed in 2 patients in the papaverine group and 1 in the verapamil-nitroglycerin group; this difference was not considered significant. Complete or functional occlusion was detected by postoperative angiography in 13 grafts (10 in the papaverine group and 3 in the verapamil-nitroglycerin group). Multivariate regression analysis revealed that topical papaverine and grafting to the right coronary artery significantly increased the rate of occlusion of radial artery grafts. Although further studies are needed, our data support the view that topical verapamil-nitroglycerin reduces the incidence of radial artery graft occlusion.

Inferior vena cava occlusion secondary to an inflammatory abdominal aortic aneurysm.

Inflammatory abdominal aortic aneurysms (IAAAs) represent 3% to 10% of all AAAs. However, inferior vena cava occlusion secondary to an IAAA is rarely reported. We report a case of inferior vena cava occlusion secondary to an IAAA presenting deep venous thrombosis. As it is crucial to avoid pulmonary embolism and excessive blood loss during an operation, we pre-operatively implanted a venous filter and minimized intra-operative dissection that allowed successful operative repair.

Identification of tissue factor and platelet-derived particles on leukocytes during cardiopulmonary bypass by flow cytometry and immunoelectron microscopy.

The extrinsic coagulation system initiated by tissue factor (TF) appears to be a major procoagulant stimulus during cardiopulmonary bypass (CPB), although the precise mechanisms remain to be revealed. We recently reported the appearance of TF-bearing leukocytes during CPB and described their role in promoting coagulation. In this study, we visually identified the in-vivo appearance of TF-bearing leukocytes and platelet-derived particles on leukocytes in the pericardial blood during cardiac surgery with CPB, by flow cytometry and immunoelectron microscopy. Preliminary flow cytometric experiments showed that the proportion of TF-positive or both TF- and platelet antigen CD41a-positive leukocytes was increased markedly in pericardial blood obtained during CPB, compared with the proportions in preoperative circulating blood. Immunoelectron microscopic analysis revealed that both monocytes and polymorphonuclear leukocytes in the pericardial blood express TF. On the surfaces of these cells, CD41a-positive or both CD41a- and TF-positive platelet-derived particles were observed. Platelet-derived particles include not only microparticles, but also platelets themselves. Leukocytes from preoperative circulating blood contained far fewer of these particles. Our results demonstrate the in-vivo appearance of TF-bearing platelet-derived particles on leukocytes during cardiac surgery with CPB. These findings may be important for the development of strategies to control procoagulant activities during and after cardiac surgery.

Bat speed, trajectory, and timing for collegiate baseball batters hitting a stationary ball.

The aims of this study were to examine whether batters hit stationary balls at the time of peak speed of the bat head and whether the impact occurs at the lowest point of the bat trajectory. Eight university baseball players hit three balls, each hung with a string; each ball was made of a different material and was different in weight. Bat movement was captured by four 240-Hz infrared cameras and analysed three-dimensionally. Time for peak speed of the bat head varied according to the conditions. When stationary balls of standard weight were used, the bat head was at maximum speed at impact with the ball; then, it decelerated drastically owing to the impact. In contrast, maximum speed was obtained after impact when lightweight stationary balls were used. The time-speed profile of the bat head before impact in the lightweight ball condition was identical with that in the standard weight ball condition. Regardless of conditions, the timing of the lowest point of the bat head was nearly identical for each batter and most participants hit the stationary balls at about the lowest point of the bat trajectory.

Physiological comparison of off-pump and on-pump coronary artery bypass grafting in patients on chronic hemodialysis.

OBJECTIVES: Despite the long-term benefit, the operative results of conventional coronary artery bypass grafting for chronic hemodialysis patients remain unsatisfactory. The efficacy of off-pump coronary artery bypass grafting for hemodialysis patients is yet to be determined. The purpose of this study was to investigate the postoperative physiology of off-pump coronary artery bypass grafting for hemodialysis patients. METHODS: Twenty-five hemodialysis cases who underwent isolated coronary artery bypass grafting were reviewed. Fifteen of these patients underwent off-pump coronary artery bypass grafting (off-group) and 10 underwent on-pump coronary artery bypass grafting (on-group). Comparisons were made in cardiac function (cardiac index and stroke volume index), respiratory function (AaDO2), hemodialysis management (blood urea nitrogen, creatinine, right atrial pressure, pulmonary wedge pressure), and bleeding tendency (postoperative blood loss and blood transfusion). RESULTS: There was no operative mortality, but 3 major postoperative complications occurred (2 sternal wound infections in the off-group and 1 pneumonia in the on-group). There was no difference in cardiac index or stroke volume index. AaDO2 was significantly lower in the off-group. Plasma concentrations of blood urea nitrogen and creatinine were similar between groups. Right atrial pressure was lower and pulmonary wedge pressure tended to be lower in the off-group. Postoperative bleeding and blood transfusion were similar between groups. CONCLUSION: Our study confirmed that off-pump coronary artery bypass grafting is feasible for hemodialysis patients. Physiologic data showed that off-pump coronary artery bypass grafting might be effective in preserving postoperative lung oxygenation.

Matrix metalloproteinase inhibitor (ONO-4817) attenuates ischemia-reperfusion injury in rat lung.

BACKGROUND: Ischemia-reperfusion injury of the lungs seems to be initiated by the activation of alveolar macrophages, and mediated by matrix metalloproteinases (MMP)s, although their roles have not been fully elucidated. Therefore, we used a novel MMP inhibitor (ONO-4817) with high affinities for MMP-2 and MMP-9 to investigate the roles of MMPs in reperfusion injury of the lungs. MATERIAL/METHODS: After 18 h of cold ischemia, isolated rat lungs were ventilated and reperfused. Lungs without ischemia served as controls. Lungs were reperfused with fresh blood with or without the MMP inhibitor for 120 min at 37 degrees C. RESULTS: The oxygenation capacity of lungs after ischemia deteriorated progressively during 120 min of reperfusion, but was preserved by the MMP inhibitor (p<0.05). The histopathology of the lungs after ischemia-reperfusion showed interstitial edema accompanied by neutrophil migration, and the number of neutrophils, but not macrophages, in the broncho-alveolar lavage increased to more than two-fold the value in control lungs without ischemia (p<0.01). These changes were attenuated by the MMP inhibitor (p<0.01). Similarly, an increase in the tissue malondialdehyde level in lungs after ischemia-reperfusion was ameliorated by the MMP inhibitor (p<0.01). The expressions of CD11c and CD31 adhesion molecules in extracted alveolar macrophages increased in lungs after ischemia-reperfusion compared with control lungs without ischemia, and the MMP inhibitor had no obvious effect. CONCLUSIONS: Our data show that ONO-4817 prevented neutrophil migration into the interstitial space and alveolus in the lungs, and reduced the production of oxygen free radicals, suggesting that this is an important mechanism in reperfusion injury.

Hand circulation after radial artery harvest for coronary artery bypass grafting.

Despite wide spread use of the radial artery (RA) graft for coronary artery bypass grafting, the change of hand circulation after RA harvest has not been fully clarified. Severe hand ischemia such as resting pain or gangrene is a rare complication and has been reported in 4 patients. These cases resulted from occlusive artery disease in forearm, which should be carefully explored before RA harvest. Incidence of mild hand ischemia such as hand claudication or fatigue is unknown, but our study suggested that around 10% of the patients developed mild hand ischemia after RA harvest. The blood flow to the forearm territory was decreased by 20% after RA harvest despite the compensatory dilatation of ulnar artery. The presence of low perfusion in the affected hand has been pointed out in some studies. We reported the decreased tissue oxygenation of the affected hand during hand grip exercise. The Allen test is the most popular preoperative screening method, but is associated with considerable numbers of false-positive and false-negative results. Full length scanning of ulnar artery by ultrasonography seems to have a lower false-positive rate. But further clinical experience is necessary to establish a more reliable screening method.

Safe coronary artery occlusion with a new tourniquet in off-pump bypass grafting.

Coronary artery occlusion during off-pump coronary artery bypass grafting may lead to mechanical trauma of the arterial wall. My colleagues and I describe a safe coronary artery occlusion technique in off-pump bypass grafting that uses a new spring-equipped tourniquet, which enables precise adjustment of the least force necessary to occlude the coronary flow. This prevents snare-induced vessel wall damage.

Aprotinin attenuated ischemia-reperfusion injury in an isolated rat lung model after 18-hours preservation.

OBJECTIVE: Ischemia-reperfusion injury is a major factor in the early phase of lung transplantation. We hypothesized that aprotinin, a nonspecific serine protease inhibitor, attenuates ischemia-reperfusion lung injury by inhibiting the inflammatory response and suppressing NADPH oxidase. METHODS: We used an isolated rat lung model to test the above. A Control group was immediately perfused with fresh heparinized allogeneic blood after lung harvest without an ischemic period. Study lungs were flushed with low-potassium dextran (LPD) solution and stored for 18h at 4 degrees C then divided into two groups: the LPD group was flushed with LPD solution only, and the LPD+A group was flushed with LPD solution +200KIU/ml aprotinin. Lungs in all three groups were then reperfused with fresh heparinized allogeneic blood for 120min at 37 degrees C. RESULTS: Throughout reperfusion, PO(2) levels in the LPD+A group were similar to those in the Control group; although in the LPD group, PO(2) levels were significantly lower (P<0.05). Tissue MDA levels were significantly higher in the LPD group than the Control and LPD+A groups (P<0.05). IL-8 levels were significantly higher in the LPD group than the Control group (P<0.05), while in the LPD+A group they were similar to those in the Control group. Histological evaluation showed interstitial edema accompanied by neutrophil extravasation in the LPD group, whereas this effect was modest in the LPD+A group. An additional study of ischemia-reperfusion in an alveolar macrophage culture showed that the activitvation of NADPH oxidase, and translocation of p47(phox) from the cytosol to the membrane were suppressed in aprotinin group. CONCLUSIONS: Aprotinin attenuates ischemia-reperfusion lung injury by inhibiting the early inflammatory response, neutrophil extravasation and the production of oxygen free radicals through inhibition of the activation of the NADPH oxidase. The inhibition of p47(phox) translocation in alveolar macrophage seemed involved in this mechanism of aprotinin.

Effects of the postoperative administration of diltiazem on renal function after coronary artery bypass grafting.

BACKGROUND: Radial artery grafts are used for coronary artery bypass grafting (CABG), and postoperative antispasm therapy with diltiazem is performed widely. Some investigators have warned that diltiazem administration after cardiac surgery is harmful to renal function. We designed a retrospective study to investigate the renal and hemodynamic effects of the postoperative administration of diltiazem in patients undergoing CABG. METHODS: Subjects were 90 consecutive CABG patients. All were treated with diltiazem during surgery (a 0.1 mg/kg bolus injection followed by continuous infusion at 2 microg x kg(-1) x min(-1)). In the 50 patients (diltiazem group) with a radial artery graft, intravenous diltiazem administration was continued until the oral intake of diltiazem (90 mg/d) was begun to avoid graft spasms. In the remaining 40 patients without a radial artery graft, diltiazem was not continued postoperatively (control group). Postoperative renal function, assessed by serum creatinine level and creatinine clearance, and hemodynamic variables (heart rate, arterial pressure, pulmonary wedge pressure, cardiac index, left ventricular stroke work index) was compared between the two groups. RESULTS: Renal function: Serum creatinine concentrations on postoperative days 1 through 7 were lower, and the endogenous creatinine clearance in the early postoperative period was higher in diltiazem group than in control group, although the differences were not significant. Hemodynamics: Heart rate was lower in diltiazem group than in the control group, but blood pressure, pulmonary wedge pressure, cardiac index, left ventricular stroke work index, and urinary output were similar between the groups. CONCLUSIONS: Our results confirmed that intravenous diltiazem treatment in patients undergoing CABG is not harmful to renal function.

Oral cibenzoline reduces postoperative atrial fibrillation in coronary artery bypass grafting.

OBJECTIVE: The objective of the present study was to investigate the effectiveness of postoperative oral administration of cibenzoline for the prevention of atrial fibrillation (AF) in coronary artery bypass grafting (CABG). METHODS: A total of 39 patients who underwent isolated CABG from September 2000 to February 2001 and who took oral cibenzoline (300 mg per day for 10 days beginning immediately after surgery) were compared to 59 patients who underwent surgery in our department 8 months prior to the study and who did not take cibenzoline for incidence of postoperative AF. Exclusion criteria encompassed age (>80 years), low ejection fraction (<30%), high serum creatinine level (>2.0 mg/dL), and history of supraventricular arrhythmia with or without treatment by anti-arrhythmic drugs. RESULTS: Postoperative AF occurred in 2 patients in the cibenzoline group (2/35, 5.7%) and 20 patients in the control group (20/59, 33.9%). There were significant differences in the incidence of postoperative AF (p = 0.002). Multivariate analysis revealed that the administration of cibenzoline reduced the incidence of AF significantly, and that a large number of bypass grafts significantly contributed to postoperative AF in CABG. The number of bypass grafts was significantly larger in the cibenzoline group, indicating that cibenzoline administration significantly suppresses the incidence of AF after CABG in high-risk patients. CONCLUSIONS: Postoperative administration of oral cibenzoline for 10 days is one effective method for the prevention of AF after CABG.

Endoscopic radial artery harvesting: our initial experience and results of the first 25 patients.

BACKGROUND: The radial artery has become an increasingly popular arterial conduit for coronary artery bypass grafting (CABG). However, the traditional open harvesting technique requires a long incision, and is therefore associated with some wound complications and cosmetic problems. Here, we describe our experience of endoscopic radial artery harvesting (ERAH) through a small incision in 25 patients who underwent CABG. MATERIALS AND METHODS: Between February 2, 2004 and January 7, 2005, a total of 25 patients (4 females; mean age: 64+/-10 years) underwent ERAH using the VasoView System (Guidant Corporation, Indianapolis, IN) at our institution. All patients underwent a preoperative Allen test to assess the competence of the palmer arch. Twenty-four radial arteries were harvested from the nondominant arm and one from the dominant arm. The mean clinical follow-up was 8+/-2.9 months. RESULTS: All radial arteries were harvested through a 2-cm incision at the wrist, successfully removed with ERAH and successfully used as CABG conduits. The mean harvest time was 59+/-11 min, and the mean harvested length was 17+/-1.7 cm. No adjunctive procedures were required during vessel harvesting, and no conversions to the open technique were necessary. Harvesting complications included 2 cases of postoperative hematoma and 7 cases of superficial radial nerve paresthesia. Five postoperative angiographies were performed and all radial arteries were patent. Overall, 24/25 (96%) patients were satisfied with the procedure. CONCLUSION: The ERAH technique was performed as safely as the traditional open technique and the harvested radial arteries were acceptable as CABG conduits. In particular, patient satisfaction with the procedure regarding the cosmetic results was excellent.

Non-viral in vivo thrombomodulin gene transfer prevents early loss of thromboresistance of grafted veins.

OBJECTIVE: Immediate loss of thrombomodulin activity in the endothelium of vein grafts has been demonstrated during 90 min exposure to arterial circulation; this loss of activity is ascribed as an important cause of early thrombosis. Conventional ex vivo gene transfection after vein harvest cannot cover this acute period immediately after implantation. We have established a highly efficient non-viral gene therapy protocol utilizing modified transferrin receptor-facilitated gene transfer. Using this technique, we examined whether in vivo thrombomodulin gene therapy, directed to the endothelium of rat veins 2 days prior to grafting, may prevent thromboresistance impairment of vein grafts under simulated arterial circulation. METHODS: Abdomen of SD rat was opened and cationic liposome:transferrin:thrombomodulin gene complexes or the vector without DNAs were applied to the inferior vena cava of rats while blood flow was reduced by proximal and distal clamping. After 2 days, the transfected veins were harvested and thrombomodulin expression and thromboresistance properties determined before and after exposure to an artificial circuit. RESULTS: The trial of gene transfection using variable doses of DNAs confirmed that 7.5 microg of total DNAs was the most efficient quantity for thrombomodulin gene transfection to IVCs, although accompanying an increase of gene expression in other downstream organs. By transfection of the thrombomodulin gene in IVCs, the generation capacity of activated protein C in venous endothelium increased three-fold compared with veins treated with vector alone (P<0.01). Under simulated arterial circulation, perfusion of veins treated with vector alone decreased thrombomodulin activity to 36% of preperfused levels (P<0.01), whereas transfected grafts preserved the activity at normal vein endothelium levels even after perfusion. Consequently, the increase in endothelial thrombin activity induced by simulated arterial circulation was markedly attenuated in transfected veins (P<0.01), while immunohistochemistry confirmed the preservation of endothelial lining. CONCLUSIONS: Transferrin receptor-facilitated in vivo gene transfer to the inferior vena cava resulted in sufficient thrombomodulin gene expression immediately after graft implantation and subsequent maintenance of thromboresistance even after exposure to arterial pressure. Although further studies are needed, the present results suggest the possibility of gene therapy targeting acute phases of vein graft disease.

Formation of tissue factor-bearing leukocytes during and after cardiopulmonary bypass.

During cardiopulmonary bypass (CPB), the extrinsic coagulation system initiated by tissue factor (TF) is a major procoagulant stimulus. TF is present in surgical wounds and could be expressed on activated monocytes. However, recent studies have suggested that collagen stimulation rapidly induces TF by leukocyte-platelet complex formation. Therefore, the appearance of TF-bearing leukocytes and their effect on promoting coagulation were investigated in 5 patients undergoing coronary bypass surgery. Neutrophils and monocytes positive for CD41a and TF increased abruptly in circulating blood during CPB. Their increase was most prominent in blood pooled in the pericardial cavity. Monocytes, but not neutrophils positive for TF showed a second peak one day after operation, which accords with the increase in TF mRNA levels in leukocytes. Similarly, an increase in leukocytes positive for TF accords with the activated factor X generation assay using isolated leukocytes, and with an increase in thrombin-antithrombin complex in circulating blood. The second increase in TF-positive monocytes seems to be responsible for these coagulation parameters that remained high one day after operation. After 10 min of blood incubation stimulated by collagen in vitro, simulating activation in the pericardial cavity, significant increases in neutrophils and monocytes positive for TF and platelet were observed. Our present study suggested the involvement of two distinct mechanisms for the appearance of TF-bearing leukocytes responsible for promoting coagulation: the quick appearance being partly explained by the formation of leukocyte-platelet complex that occurs mainly in the pericardial cavity, and the slow appearance via transcriptional activation in monocytes.

Oxygen pressure measurement during grip exercise reveals exercise intolerance after radial harvest.

BACKGROUND: Exercise intolerance of the hand after harvest of the radial artery is not well understood, although mild reductions of blood flow to the hand are reported. To ascertain its prevalence, patient symptoms implying potential exercise intolerance were evaluated by measuring transcutaneous oxygen pressure of the hand during grip exercise. For ascertaining predictive values, we verified ulnar flow reserve measured by Doppler ultrasonography before the harvest of radial artery. METHODS: Forty patients whose radial artery was harvested for coronary bypass graft, were interviewed and tested 1 year after operation, and their preoperative ultrasonographic data compared. RESULTS: Five patients (12.5%) had mild symptoms implying exercise intolerance. Exercise tests revealed severe decreases in tissue oxygenation in 7 patients (17.5%), but in accordance with symptoms (p = 0.0018). Tissue oxygenation in the operated hand was lower than in the nonoperated even in asymptomatic patients (p = 0.0011). Preoperative Doppler echography revealed that ulnar arteries of symptomatic patients were smaller (p = 0.0019) and carried lower blood flows during manual compression of the radial artery (p = 0.0004) compared with those of asymptomatic patients. Smaller ulnar arteries (less than 1.4 mm/m(2)) with poor flow reserves (less than 60 mL x min(-1) x m(-2) during radial compression) appear to indicate risks for exercise intolerance (p = 0.0004). CONCLUSIONS: More than 10% of patients after harvest of radial arteries had mild symptoms implying exercise-intolerance, which accorded with abnormal tissue oxygenation during grip exercise. Work habits of patients should be considered in radial harvest decisions, especially if preoperative Doppler echography indicates lower flow reserves for the ulnar artery.