Biomedical subjects
Publications and source records attributed to Y Hatakeyama.
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The stabilizing function of the inferior glenohumeral ligament of the anterior band and posterior band has been investigated, but little is known about the function of the axillary pouch. The strain of the 3 portions of the inferior glenohumeral ligament in 17 fresh-frozen cadaveric shoulders was measured with use of linear transducers. The measurements were performed under the following conditions: 0 degrees, 30 degrees, 45 degrees, and 60 degrees of glenohumeral elevation in the coronal, scapular, and sagittal planes and internal to external rotations in 10 degrees increments. The anterior band and axillary pouch showed significant strain increases when the arm was elevated and externally rotated in the coronal and scapular planes but no increase in the sagittal plane. The posterior band showed no strain in the coronal and scapular planes, but a significant strain increase with the arm elevated and internally rotated in the sagittal plane. We conclude that the anterior band and axillary pouch, which showed the greatest strain in abduction and external rotation, are anterior stabilizers, whereas the posterior band, which showed the greatest strain in flexion and internal rotation, is a posterior stabilizer. We recommend that the 6 o'clock position be firmly repaired during the Bankart procedure.
We studied the strain on the superior labrum of 10 fresh-frozen cadaveric shoulders with the arm in simulated positions of a pitching motion. We used linear transducers to measure the strain in both the anterior and posterior superior labrum with the arm in various planes and rotations simulating the motions of pitching: early cocking, late cocking, acceleration, deceleration, and follow-through. Predetermined loads, according to the percent of maximum voluntary contraction of the biceps muscle during each phase of pitching, were calculated and applied to the long head of the biceps tendon using a spring device. Only during the late cocking phase, when the arm was in maximal external rotation, was the increase in strain statistically significant for the anterior and posterior portions and the strain on the posterior portion significantly greater than that on the anterior portion of the labrum. The increased strain in the posterior portion may be due to the anatomic orientation of the long head of the biceps tendon at the superior labrum. The increased strain in the late cocking phase may contribute to the detachment of the labrum with the eccentric contraction of the biceps muscle that occurs with rapid extension of the elbow.
Twelve cadaveric shoulders were used to determine the effects of release of the superior capsule and the coracohumeral ligament on the strain in the repaired rotator cuff tendon. A rotator cuff tear (2 cm wide and 1.5 cm long) was created and repaired under a 3-kg tensile force. The strain in the repaired tendon was measured with use of linear transducers with the arm in 50 different positions. Release of either the superior capsule or the coracohumeral ligament diminished the tension of the repaired rotator cuff by an average of 25% with the arm in adduction. Release of both of these structures further reduced the tension by an average of 44% in adduction and 43% to 60% with the arm in 15 degrees of elevation. The maximum reduction of tension in the repaired rotator cuff occurred when both the superior capsule and coracohumeral ligament were divided and when the arm was positioned in adduction and in 60 degrees of external rotation. Release of the coracohumeral ligament is equally as efficient as releasing the superior capsule in reducing the strain of the repaired rotator cuff. Releasing both structures seems to be desirable when releasing one structure or the other is not sufficient.
In 14 cadaveric shoulders, a rotator cuff tear (2 cm wide and 1.5 cm long) was created and repaired under a 3-kg tensile force with the arm in adduction. Strain on the repaired tendon was measured at 0 degrees, 15 degrees, 30 degrees, and 45 degrees of elevation in the sagittal, scapular, and coronal planes and from 60 degrees of internal rotation to 60 degrees of external rotation. The strain in all of the planes decreased significantly with the arm elevated more than 30 degrees. With 30 degrees of elevation in the scapular and coronal planes, the strain increased in internal rotation and decreased in external rotation. In all of the positions measured, the strain in the sagittal plane was significantly greater than in the other planes. We concluded that more than 30 degrees of elevation in the coronal or scapular plane and rotation ranging from 0 degrees to 60 degrees of external rotation compose the safe range of motion after repair of the rotator cuff.
A micronucleus test was conducted on the peripheral blood of mice and rats utilizing acridine orange-coated slides (AO-coated method) after oral administration of benzene. Blood was sampled at 0, 24, 48, and 72 h after administration of benzene at doses of 500, 1000, and 2000 mg/kg in both mice and rats. The highest occurrence of micronucleated reticulocytes (MNRETs) was observed at 48 h after administration in both species. Species differences was found in the frequency of MNRETs, with the number being lower in rats than in mice. The present results indicate that the micronucleus test can easily detect chromosome aberrations in peripheral blood induced by benzene administration in both mice and rats. Furthermore, the AO-coated method used in this study was simpler to perform and allowed for easier detection of the effect than the conventional method.
BACKGROUND/AIMS: The purpose of this study is to investigate the possible participation of inflammatory cytokine release from macrophages/monocytes following liver surgery on cirrhotic patients in the pathogenesis of postoperative organ failures. MATERIALS AND METHODS: Postoperative changes in tumor necrosis factor-a and interleukin-1 beta production in peripheral blood monocytes stimulated by lipopolysaccharide were examined in cirrhotic patients with hepatocellular carcinoma undergoing hepatic resections. RESULTS: Monocytes separated from the blood in cirrhotic patients prior to operation showed a greater ability to produce tumor necrosis factor-a and interleukin-1 beta than those in healthy volunteers. Monocytes in postoperative cirrhotic patients showed a greater ability to produce tumor necrosis factor-a and interleukin-1 beta in the presence of lipopolysaccharide than healthy controls and preoperative cirrhotic patients. In the case of postoperative hepatic failure, tumor necrosis factor-a and interleukin-1 beta production in monocytes showed a remarkable rise along with progression toward hepatic failure. CONCLUSION: These results indicate that tumor necrosis factor-a and interleukin-1 beta play an important role in the pathogenesis of postoperative liver failures. When there are any stimuli to produce cytokines in monocytes, such as ischemia, significant tissue injury and/or endotoxin, organ failures could develop and progress subsequently.