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Biomedical subjects

O Shigeta

Publications and source records attributed to O Shigeta.

33 records · Page 2Linked to original sources
PubMed1994

[A case of operation for acute postinfarction mitral insufficiency due to papillary muscle rupture].

A 75-year-old man was brought to hospital with complaining of chest pain. He was diagnosed acute myocardial infarction and treated medically using thrombolytic drugs. Without chest pain relieved, cardiac catheterization revealed three coronary vessel disease and severe mitral insufficiency (MR). MR was diagnosed due to papillary muscle rupture by echocardiography. After being transferred to our hospital, the patient developed in shock and underwent emergency operation with IABP inserted. Triple CABGs (to LAD, PD and 4PL) and mitral valve replacement were performed using saphenous vein grafts and a mechanical valve (Carbomedicus 25 M). The patient recovered gradually and discharged one and a half month after operation.

Aged↗
PubMed1994

[A case of bronchial rupture and pulmonary laceration caused by blunt chest trauma].

A 37-year-old female was crushed by a traffic accident. She was in severe respiratory distress. A chest X-ray revealed right pneumothorax and multiple rib fractures. Shortly after the initiation of the positive pressure ventilation, severe subcutaneous emphysema developed and she became shock. The bronchoscopy showed the rupture of the right main bronchus which was repaired through a right posterolateral thoracotomy using interrupted monofilament PPP sutures. Pulmonary lacerations were also repaired by the same sutures. Postoperative bronchoscopic examination showed good healing without any stricture. It cannot be overemphasized that accurate diagnosis and urgent surgical management is mandatory in patients with bronchial rupture.

Accidents, Traffic↗
PubMed1994

[A case of acute aortic dissection associated with myxedema].

A 53-year-old female, who had been severe hypothyroidism for about ten years, was admitted Stanford type A acute aortic dissection. The replacement of ascending aorta with a composite graft and coronary artery bypass grafting were performed immediately. During the post operative period, many complications occurred including delayed awakening from anesthesia, paralytic ileus, colon perforation, hyperbilirubinemia, pulmonary edema, cerebral hemorrhage and bacterial endocarditis. In this case, intravenous administration of steroid and thyroid hormone was effective to keep hormone level in the normal range although enteral administration was ineffective. It was suggested that early active supplement therapy is mandatory to prevent postoperative complications.

Acute Disease↗
PubMed1993

Extra-anatomic bypass for aorto-iliac occlusive disease in octogenarians.

Fifteen patients over 80 years of age with aorto-iliac occlusive disease (AIOD) underwent surgical revascularization of an ischemic lower extremity by extra-anatomic bypasses. The mean age at operation was 81.7 years, ranging from 80 to 86 years. Surgical revascularization of the ischemic lower limbs could safely be performed with an extra-anatomic bypass in these patients without any major complications. The mean follow-up period was 32.7 months. Eight patients died during the follow-up, only one of them died from myo-nephropathic metabolic syndrome related to acute graft occlusion. As a long-term result, the cumulative survival after 37 months was only 23.9%, while the actual graft patency rate was 43.8% after 60 months in this series. The survival period with an improved quality of life after surgical intervention reached a level of approximately 40% of that for the general population. There should be no hesitation over whether to carry out surgical intervention for AIOD in patients over 80 years of age, because a reasonable extension of life can be obtained by an extra-anatomic bypass.

Aged↗
PubMed1993

[Pseudo-false aneurysm of the left ventricle perforated into the right ventricle--a case report].

A case of pseudo-false aneurysm of the left ventricle perforated into the right ventricle was reported. The patient was 60-year-old male with acute inferior myocardial infarction. Echocardiography showed a thin wall cavity on the apex of the right ventricle. Communication between the left ventricle and the right ventricle was detected on pulsed Doppler echocardiography. Surgery revealed a pseudo-false aneurysm in the free wall of the right ventricle communicating to both ventricles. We emphasize the importance of preoperative morphological and hemodynamic evaluation with Doppler echocardiography in the case of post-myocardial infarction ventricular septal perforation.

Heart Aneurysm↗
PubMed1992

Protection of platelets during long-term extracorporeal membrane oxygenation in sheep with a single dose of a disintegrin.

BACKGROUND: Both short- and long-term extracorporeal membrane oxygenation (ECMO) causes platelet loss and dysfunction. Bitistatin is a reversible inhibitor of the platelet glycoprotein IIb/IIIa receptor. This study tests the hypothesis that inhibition of platelets by bitistatin during initial contact with the perfusion circuit preserves platelet number and function during long-term ECMO in sheep. METHODS AND RESULTS: Bitistatin, purified from crude snake venom, was tested for its effect on platelet count, responsiveness to ADP, release of platelet factor 4, and prevention of surface-adsorbed glycoprotein IIIa in vitro and during 24 hours of ECMO in nine splenectomized sheep. During simulated extracorporeal circulation, 0.5-1.0 microgram/ml bitistatin significantly prevented platelet adhesion, attenuated release of sheep platelet factor 4, and preserved platelet responsiveness to ADP. During ECMO at 1.8 l/min for 24 hours, a single dose of bitistatin (200 micrograms/kg) (n = 4) produced higher platelet counts (p = 0.0002) and suppressed release of platelet factor 4 (p = 0.035) for 16 hours compared with five control animals. This dose of bitistatin caused an immediate inhibition of platelet aggregation; however, between 4 and 24 hours of perfusion, platelets of bitistatin-treated animals were more responsive to ADP (p < 0.0001) compared with platelets in control animals. The amount of glycoprotein IIIa antigen extracted by Triton X-100 from the perfusion circuits was reduced in bitistatin-treated sheep. CONCLUSIONS: A single dose of bitistatin given before blood contact with the ECMO circuit briefly inhibits platelet adhesion and aggregation but thereafter preserves platelet numbers and function and suppresses alpha-granule release for 12-16 hours of ECMO.

Adenosine Diphosphate↗
PubMed1992

[Surgical results of two cases of simultaneous surgery of carotid and coronary occlusive disease].

Two cases of symptomatic extracranial carotid artery stenosis associated with ischemic heart disease are reported. The first case was 72-year-old male, who was admitted because of transient ischemic attack due to the stenosis of left internal carotid artery. He had a history of myocardial infarction and coronary angiography revealed three vessel disease. The second case was 74-year-old female with diabetes mellitus. She was admitted because of cerebral infarction. The carotid angiography revealed critical stenosis of bilateral internal carotid arteries. Her coronary angiography revealed three vessel disease. Her chest symptom became unstable after her admission. In both cases, simultaneous carotid endarterectomy and coronary bypass grafting were performed with successful outcome. In the patients with symptomatic extracranial carotid occlusive disease associated with severe ischemic heart diseases, we advocate simultaneous operation both for carotid and coronary artery occlusive disease.

Aged↗
PubMed1991

Ovine platelet factor 4: purification, amino acid sequence, radioimmunoassay and comparison with platelet factor 4 of other species.

A simple method of purification of ovine platelet factor 4 (PF4) is described. Material released by freezing and thawing suspension of washed sheep platelets was fractionated by heparin-agarose chromatography and reverse phase HPLC. Purified ovine PF4 contained 85 amino acids (Mr 9130) and showed 78% homology with bovine PF4, 76% with porcine PF4, 71% homology with human PF4, and 61% with rat PF4. The heparin binding site of ovine PF4 localized in the C-terminal region of the molecule was identified as LYKKIIKRLL. The content of PF4 determined by radioimmunoassay was 22.6 (+/- 1.6 S.D.) micrograms per 10(9) platelets and 46.8 (+/- 19.6 S.D.) ng per ml platelet poor plasma collected in acid citrate dextrose in the presence of prostaglandin E1. PF4 was rapidly released during stimulation of ovine platelets by collagen.

Amino Acid Sequence↗
PubMed1990

[Fatal delayed hemolytic transfusion reaction in a postoperative case of traumatic aortic rupture].

A 52-year-old woman with traumatic rupture of the thoracic descending aorta had a history of previous blood transfusion 23 years ago. This time, she received 4,600 ml of blood transfusion during the replacement procedure of thoracic aorta. On the 12th postoperative day, she had acutely progressive severe jaundice, anemia and hepatosplenomegaly. All transfused blood was compatible by bromelin method before operation. Serological studies revealed a secondary response of hemolytic transfusion reaction due to anti E and anti c antibodies. She fell into severe bilirubinemia (66 mg/dl) and anuria, and died on 19th day after operation. A positive Coombs test in a patient who has been transfused recently must be interpreted with great caution. The "coated" cells may be incompatible donor cells in a patient who has antibodies from a prior transfusion. The incompatibility occasionally leads to delayed transfusion reaction that may stimulate "autoimmune" hemolytic anemia.

Anemia, Hemolytic↗
PubMed1989

[Coexistence of abdominal aortic aneurysm and intraabdominal malignancy; two case reports].

We experienced two cases of abdominal aortic aneurysm which had intra-abdominal malignancy (early gastric cancer). Case 1 was a 72 year-old man who was treated by two-stage operation of them. Gastrectomy was performed about 7 months prior to the aneurysmectomy. Case 2 was a 70 year-old man who was diagnosed both lethal diseases, renal dysfunction, chronic respiratory failure and multiple ventricular arrhythmia. He was treated by one-stage operation and was discharged with no complications. Coexistence of abdominal aortic aneurysm and intra-abdominal malignancy is rare and it is difficult to decide whether to operate the malignancy first, the aneurysm first or both simultaneously. In Japan, 28 cases were reported and 18 cases could be analyzed in detail. In these cases, most frequent coincidental malignancy was the gastric cancer (13/18, 72.2%) and one-stage operation was performed in 8 (44.4%) cases. In general, the risk of infection during upper gastrointestinal surgery is less than that during lower abdominal surgery. We concluded therefore that concomitant resection of the upper gastrointestinal malignancy, especially early gastric cancer, should be considered.

Aged↗
PubMedDate not supplied

Method of noninvasive and continuous hemolysis/thrombogenesis measurement by laser photometry during artificial heart development.

The purpose of this research is to propose and develop a method to measure hemolysis and thrombogenesis non invasively and continuously to aid in development of an artificial heart. Generally, the optical absorption rate of hemoglobin is influenced by oxygen saturation except at the isosbestic point, which is not influenced by oxygen saturation. The authors, therefore, used an 805 nm laser diode, an optical spectrum analyzer to obtain greater accuracy. An experimental blood circuit system was constructed using a Bio-Pump, Tygon tubing, a soft shell reservoir, and an optical measurement system. Experimental settings for monitoring hemolysis were as follows; blood volume 200 ml, blood flow 6 L/min, and afterload 200 mmHg. Blood was sampled six times (0, 30, 60, 120, 180, and 240 min), and hemolysis in each sampled was measured using a colorimetric method. Comparing continuous laser measurement data with the sample data, an adequate correlation is obtained, proving that the dynamic trend of hemolysis could be continuously measured. Furthermore, to analyze the process of thrombogenesis, simple experiments were performed using blood neutralized by protamine. As a result, the authors could see the process of thrombogenesis as it occurred and could confirm that this method is able to dynamically detect hemolysis and thrombogenesis.

Biomedical Engineering↗
PubMedDate not supplied

Species differences in erythrocyte mechanical fragility: comparison of human, bovine, and ovine cells.

The erythrocyte destruction rate under constant shear stress was measured to clarify species differences in red blood cell (RBC) mechanical fragility between human, bovine, and ovine cells. Blood was collected from healthy donors by venipuncture. RBC age fractionation was performed by high speed centrifugation (20 min at 12,000 g). Relatively young, middle, and old age RBCs was suspended in Dulbecco's phosphate buffered saline to adjust the hematocrit to 35%. Uniform shear stress was applied to each sample contained in a concavo-convex Couette flow testing machine. Young and old aged samples were exposed to 300 dyne-sec-cm2 for 0 and 15 min. Middle aged samples were exposed to 300 dyne-sec-cm2 for 0, 5, 10 and 15 min. Liberated hemoglobin was estimated by tetramethylbenzidine colorimetric measurement and the erythrocyte destruction rate was calculated. Older samples had a higher hemolysis rate than younger samples in every species. The destruction under constant shear stress is approximately linear in time. Mechanical fragility of ovine and bovine RBCs was 1.8 and 0.5 times as large as human RBCs, respectively. These values could serve as universal standards when extrapolating animal hemolysis data for any blood pump to predict its safety and biocompatibility in human clinical trials.

Animals↗