Time-varying motor control strategy for proximal-to-distal sequential energy distribution: insights from baseball pitching.

The importance of a proximal-to-distal (P-D) sequential motion in baseball pitching is generally accepted; however, the mechanisms behind this sequential motion and motor control theories that explain which factor transfers mechanical energy between the trunk and arm segments are not completely understood. This study aimed to identify the energy distribution mechanisms among the segments and determine the effect of the P-D sequence on the mechanical efficiency of the throwing movement, focusing on the time-varying motor control. The throwing motions of 16 male collegiate baseball pitchers were measured by a motion capture system. An induced power analysis was used to decompose the system mechanical energy into its muscular and interactive torque-dependent components. The results showed that the P-D sequential energy flow during the movement was mainly attributed to three different joint controls of the energy generation and muscular torque- and centrifugal force-induced energy transfer. The trunk muscular torques provided the primary energy sources of the system mechanical energy, and the shoulder and elbow joints played the roles of the energy-transfer effect. The mechanical energy expenditure on the throwing hand and ball accounted for 72.7% of the total muscle work generated by the trunk and arm joints (329.2 J). In conclusion, the P-D sequence of the throwing motion is an effective way to utilize the proximal joints as the energy source and reduce muscular work production of the distal joints. This movement control assists in efficient throwing, and is consistent with the theory of the leading joint hypothesis.

Time-Enhancement Curve of Four-Dimensional Computed Tomography Predicts Aneurysm Enlargement with Type-II Endoleak after Endovascular Aneurysm Repair.

OBJECTIVE: We investigated the hemodynamic features of Type-II endoleaks after endovascular aneurysm repair (EVAR) using four-dimensional (4D) computed tomography (CT) to identify patients with aneurysm enlargement. METHODS: During a 13-month period (January 2017-January 2018) at our institution, we performed 4D-CT examinations in 13 patients after EVAR because of suspected Type-II endoleaks. Three patients were excluded from the study because of other endoleaks or absence of detectable endoleaks. The ramaining 10 patients were divided into two groups: enlargement group (n = 4), in which the aneurysm volume increased, and stable group (n = 6), in which the aneurysm remained stable or shrank. A CT scanner and three-dimensional workstation were used. All images were obtained using a consistent protocol (22 phase scans using the test bolus tracking method). We analyzed the hemodynamics of the endoleak cavity (EC) relative to those of the aorta and evaluated the time-enhancement curves (TECs) using measurement protocols. The strengths of correlations between these factors in the two groups were analyzed statistically. RESULTS: TECs in the enlargement group showed a more gradual curve, and the upslope, the gradient of TEC in the ascending phase and the upslope index were significantly more gradual than those in the stable group (p = 0.0247, 0.0243). The EC washout and the EC washout index were also more gradual than in the stable group's (p = 0.019, 0.019). The enhancement duration was longer in the former than in the latter (80%, p = 0.0195; 70%, p = 0.0159; 60%, p = 0.0159). The CT number in the equilibrium phase was larger in the enlargement group than in the stable group (p = 0.019). CONCLUSION: The 4D-CT is useful for predicting aneurysm enlargement with Type-II endoleaks after EVAR.

[Mycotic Aneurysm of the Ulnar Artery Associated with Infective Endocarditis;Report of a Case].

A 19-year-old man, with a history of hospitalization for infective endocarditis associated with Streptococcus mitis/oralis 2 months before, was admitted to our hospital because of stomach ache and pulsatile mass on the left forearm. Computed tomography(CT) and ultrasonography revealed a thrombus in the superior mesenteric artery and an aneurysm of the left ulnar artery. As vegetation was noted on the anterior leaflet of the mitral valve, mitral valve replacement and ulnar artery aneurysmorrhaphy were performed. He was discharged 24 days after surgery without any complications. Although mycotic aneurysm is one of the complications of infective endocarditis, it is rarely formed in the ulnar artery. Moreover, mycotic aneurysm may develop even after inflammatory reaction has subsided. Thus, longterm observation of patients with infective endocarditis is necessary.

Multi-body dynamic coupling mechanism for generating throwing arm velocity during baseball pitching.

The purpose of this study was to identify the detailed mechanism how the maximum throwing arm endpoint velocity is determined by the muscular torques and non-muscular interactive torques from the perspective of the dynamic coupling among the trunk, thorax and throwing and non-throwing arm segments. The pitching movements of ten male collegiate baseball pitchers were measured by a three-dimensional motion capture system. Using the induced-segmental velocity analysis (IVA) developed in this study, the maximum fingertip velocity of the throwing arm (MFV) was decomposed into each contribution of the muscular torques, passive motion-dependent torques due to gyroscopic moment, Coriolis force and centrifugal force, and other interactive torque components. The results showed that MFV (31.6±1.7m/s) was mainly attributed to two different mechanisms. The first is the passive motion-dependent effect on increasing the angular velocities of three joints (thorax rotation, elbow extension and wrist flexion). The second is the muscular torque effect of the shoulder internal rotation (IR) torque on generating IR angular velocity. In particular, the centrifugal force-induced elbow extension motion, which was the greatest contributor among individual joint contributions, was caused primarily by the angular velocity-dependent forces associated with the humerus, thorax, and trunk rotations. Our study also found that a compensatory mechanism was achieved by the negative and positive contributions of the muscular torque components. The current IVA is helpful to understand how the rapid throwing arm movement is determined by the dynamic coupling mechanism.

[Incidentally detected bronchial artery aneurysm with combined operation for mitral regurgitation;report of a case].

A 77-year-old woman was admitted to the hospital for heart failure with orthopnea. Echocardiography revealed massive mitral regurgitation. During preoperative cardiac catheterization, an aneurysm was indentified incidentally just below the tracheal carina. Three dimensional computed tomography showed three bronchial artery aneurysms behind the pulmonary artery and the left atrium. The proximal aneurysm was the largest and was 22 mm in diameter. It was resected by retracting the ascending aorta to the left, the superior vana cava to the right and right pulmonary artery cranially under cardiopulmonary bypass, and mitral valve plasty was performed. We believed that resection of the proximal aneurysm would cause thrombotic occlusion of the other 2 aneurysms. Bronchial artery aneurysm is a rare entity that is observed in fewer than 1% of those who undergo selective bronchial arteriography. In addition, because bronchial artery aneurysm is a potentially life-threatening lesion, it should be treated promptly when diagnosed.

Intersegmental dynamics of 3D upper arm and forearm longitudinal axis rotations during baseball pitching.

The shoulder internal rotation (IR) and forearm pronation (PR) are important elements for baseball pitching, however, how rapid rotations of IR and PR are produced by muscular torques and inter-segmental forces is not clear. The aim of this study is to clarify how IR and PR angular velocities are maximized, depending on muscular torque and interactive torque effects, and gain a detailed knowledge about inter-segmental interaction within a multi-joint linked chain. The throwing movements of eight collegiate baseball pitchers were recorded by a motion capture system, and induced-acceleration analysis was used to assess the respective contributions of the muscular (MUS) and interactive torques associated with gyroscopic moment (GYR), and Coriolis (COR) and centrifugal forces (CEN) to maximum angular velocities of IR (MIRV) and PR (MPRV). The results showed that the contribution of MUS account for 98.0% of MIRV, while that contribution to MPRV was indicated as negative (-48.1%). It was shown that MPRV depends primarily on the interactive torques associated with GYR and CEN, but the effects of GYR, COR and CEN on MIRV are negligible. In conclusion, rapid PR motion during pitching is created by passive-effect, and is likely a natural movement which arises from 3D throwing movement. Applying the current analysis to IR and PR motions is helpful in providing the implications for improving performance and considering conditioning methods for pitchers.

Aorto-left renal vein fistula caused by a ruptured abdominal aortic aneurysm.

Retroaortic left renal vein is a malformation in which the left renal vein courses dorsal to the abdominal aorta. In patients with abdominal aortic aneurysm, an aorto-left renal vein fistula can form if the left renal vein is sandwiched between the aneurysm wall and lumbar vertebrae. The patient was an 84-year-old man with lower back pain. We performed a contrast-enhanced computed tomography (CT), although renal dysfunction was noted. The CT showed a ruptured juxta-renal abdominal aortic with aorto-left renal vein fistula. This clinical condition can cause severe renal dysfunction, in spite of which an enhanced contrasted CT scan would be extremely informative preoperatively.

Energy redistribution analysis of dynamic mechanisms of multi-body, multi-joint kinetic chain movement during soccer instep kicks.

The purpose of this study is to develop a model to analyze energy redistribution mechanisms of a multi-joint limb system and to examine the mechanisms underlying the production of the mechanical energy of the system during instep kicking. Kicking movements of 11 collegiate soccer players were recorded using a motion capture system, and ground reaction force during kicks was measured. Using the experimental data and the state-space power analysis developed in the current study, the kinetic energy change of the modeled segments was decomposed into causal components due to various dynamic factors (muscular and non-muscular interactive moments). The results showed that the increase of the kinetic energy of the kicking limb resulted from the energy transfer mechanisms between the decelerated segment (a proximal segment) and accelerated segment (a distal segment), induced by a non-muscular interactive moment due to the external joint force or the centrifugal force. The proximal (thigh) to distal (shank) sequential motion pattern observed was due to the energy transfer mechanism induced by the centrifugal effect acting to accelerate the shank and decelerate the thigh. The fact suggests that effective use of that mechanism may be advantageous to enhance the kinetic energy of the kicking shank. In conclusion, energy transfer mechanisms likely play a greater role in dynamic kicking than muscle power output, and better coordination to exchange kinetic energy among segments makes kicking more efficient.

Multijoint kinetic chain analysis of knee extension during the soccer instep kick.

Although previous studies have shown that motion-dependent interactions between adjacent segments play an important role in producing knee extension during the soccer instep kick, detailed knowledge about the mechanisms underlying those interactions is lacking. The present study aimed to develop a 3-D dynamical model for the multijoint kinetic chain of the instep kick in order to quantify the contributions of the causal dynamical factors to the production of maximum angular velocity during knee extension. Nine collegiate soccer players volunteered to participate in the experiment and performed instep kicking movements while 3-D positional data and the ground reaction force were measured. A dynamical model was developed in the form of a linked system containing 8 segments and 18 joint rotations, and the knee extension/flexion motion was decomposed into causal factors related to muscular moment, gyroscopic moment, centrifugal force, Coriolis force, gravity, proximal endpoint linear acceleration, and external force-dependent terms. The rapid knee extension during instep kicking was found to result almost entirely from kicking leg centrifugal force, trunk rotation muscular moment, kicking leg Coriolis force, and trunk rotation gyroscopic-dependent components. Based on the finding that rapid knee extension during instep kicking stems from multiple dynamical factors, it is suggested that the multijoint kinetic chain analysis used in the present study is more useful for achieving a detailed understanding of the cause of rapid kicking leg movement than the previously used 2-D, two-segment kinetic chain model. The present results also indicated that the centrifugal effect due to the kicking hip flexion angular velocity contributed substantially to the generation of a rapid knee extension, suggesting that the adjustment between the kicking hip flexion angular velocity and the leg configuration (knee flexion angle) is more important for effective instep kicking than other joint kinematics.

Heparinless cardiopulmonary bypass with argatroban in dogs.

OBJECTIVES: Systemic heparinization is usually required for cardiopulmonary bypass (CPB). However, problems such as heparin-induced thrombocytopenia, protamine shock, and antithrombin III deficiency exist related to CPB with heparinization. The aim of this study was to evaluate argatroban (ARG) as a substitute for heparin during CPB. METHODS: In the pilot study, blood samples were sequentially obtained from dogs with continuous infusion of ARG at a dose of 10 (n = 6), 20 (n = 6), or 30 (n = 6) microg/kg per min for 2 h without CPB. In the main study, dogs underwent CPB for 2 h with 10 (n = 6) or 30 (n = 6) microg/kg per min of ARG or with heparin with blood samples obtained sequentially. Thrombogenicity in each group was evaluated by observation of the blood-contacting surfaces of the CPB circuits with scanning electron microscopy (SEM). Evidence of thromboembolism in the dogs was also investigated in histological specimens of the kidney and spleen in addition to microscopic observation at autopsy. RESULTS: In the pilot study, the activated coagulation time (ACT) reached a maximum level dose-dependently after continuous infusion of ARG for 30 min. ACT returned to the baseline value within 60 min after the termination of continuous infusion. In the main study, CPB with 30 microg/kg per min of ARG achieved thrombin-antithrombin III complex (TAT) level similar to that achieved by CPB with heparin. Platelet count with 30 microg/kg per min of ARG tended to be higher than that with heparin or 10 microg/kg per min of ARG. The SEM appearance of blood-contacting surfaces of the CPB circuits after infusion with 30 microg/kg per min of ARG appeared to be similar to that after infusion with heparin. Depositions on the blood-contacting surfaces of the CPB circuits were also frequently observed with 10 microg/kg per min of ARG. CONCLUSIONS: Coagulability related to CPB was controlled by the appropriate ARG dosage without the use of heparin in dogs. ARG may be a substitute for heparin in CPB.

Omental herniation through the esophageal hiatus mimics mediastinal lipomatous tumor.

A 61-year-old man with a mediastinal abnormal mass on computed tomography is presented. Sagittal sections of magnetic resonance imaging (MRI) clearly indicated the continuity of the fatty mass from the abdomen to the thorax. The diagnosis was an omental herniation through the esophageal hiatus during the operation. First, we returned the omentum into the abdominal cavity, and then repaired the hiatus. The patient had an uneventful postoperative recovery. A herniation of the omentum through the esophageal hiatus is rare; this case is the tenth found in both English and Japanese literatures. The coronal and sagittal planes of MRI were useful in distinguishing the herniation of omentum through the esophageal hiatus from lipomatous tumor. It is our intention of raising awareness about the disease.

Perforation of the descending aorta by the tip of an intra-aortic balloon pump catheter.

Perforation of the proximal descending aorta occurred in a patient on intra-aortic balloon pump (IABP) support after emergency coronary intervention for acute myocardial infarction. The IABP catheter was inserted under fluoroscopic guidance into the right femoral artery without difficulty, but after 8 h on IABP support the patient went into shock with a left hemothorax. Emergency surgery was performed with cardiopulmonary bypass and a perforation of the proximal descending aorta with active bleeding was found and successfully repaired. A distorted descending aorta in which the IABP catheter was kinked, as in the aortic arch, was discovered during surgery and confirmed postoperatively with 3-dimensional computed tomography scans, particularly in the lateral view. Not only the antero-posterior but also the lateral fluoroscopic view is recommended to prevent aortic perforation by a kinked IABP catheter.

Comparative Hemolysis Study of Clinically Available Centrifugal Pumps.

Centrifugal pumps have become important devices for cardiopulmonary bypass and circulatory assistance. Five types of centrifugal pumps are clinically available in Japan. To evaluate the blood trauma caused by centrifugal pumps, a comparative hemolysis study was performed under identical conditions. In vitro hemolysis test circuits were constructed to operate the BioMedicus BP-80 (Medtronic, BioMedicus), Sams Delphin (Sarns/3M Healthcare), Isoflow (St. Jude Medical [SJM]), HPM-15 (Nikkiso), and Capiox CX-SP45 (Terumo). The hemolysis test loop consisted of two 1.5 m lengths of polyvinyl chloride tubing with a 3/8 -inch internal diameter, a reservoir with a sampling port, and a pump head. All pumps were set to flow at 6 L/min against the total pressure head of 120 mm Hg. Experiments were conducted simultaneously for 6 h at room temperature (21o C) with fresh bovine blood. Blood samples for plasma-free hemoglobin testing were taken, and the change in temperature at the pump outlet port was measured during the experiment. The mean pump rotational speeds were 1,570, 1,374, 1,438, 1,944, and 1,296 rpm, and the normalized indexes of hemolysis were 0.00070, 0.00745, 0.00096, 0.00066, 0.00090 g/100 L for the BP-80, Sarns, SJM, Nikkiso, and Terumo pumps, respectively. The change in temperature at the pump outlet port was the least for the Nikkiso pump (1.8o C) and the most with the SJM pump (3.8o C). This study showed that there is no relationship between the pump rotational speed (rpm) and the normalized index of hemolysis in 5 types of centrifugal pumps. The pump design and number of impellers could be more notable factors in blood damage.