Biomedical subjects

M Ohmi

Publications and source records attributed to M Ohmi.

At least 19 recordsLinked to original sources

PubMed1992

Permanent pacemaker implantation in premature infants less than 2,000 grams of body weight.

Pacemaker implantation in premature infants presents technical problems because of the relatively larger size of the pulse generator compared with their bodies. A new technique with which successful generator implantation was performed in 2 premature infants less than 2,000 g of body weight is described. The generator is wrapped in a Gore-Tex surgical membrane. A piece of membrane overlying the electrical contact surface of the generator is removed, and the generator is fixed to the abdominal wall in the peritoneal cavity. The technique is simple to perform and would give relative ease in generator exchange.

Birth Weight↗

PubMed1992

Thoracic aortic operations in patients aged 70 years or older.

Thirty-one patients over the age of 70 years (group A) and 72 patients less than 69 years (group B) underwent a variety of thoracic aortic surgical procedures. Early and long-term results and cerebral function were compared between the two groups. Preoperative and postoperative cerebral function was evaluated using mini mental state-Himeji and Wechsler adult intelligence scale tests. The operative mortality of groups A and B was 12.9% and 11.1%, respectively (not significant). There were no significant differences in postoperative complications between the two groups. The late mortality rates of groups A and B were 11.1% and 9.3%, respectively (not significant). There were no significant differences between the two groups in the mini mental state-Himeji test, digit symbol, vocabulary, and total Wechsler adult intelligence scale scores before and after operation. We conclude that thoracic aortic surgical procedures in patients over 70 years of age can be performed with acceptable mortality and morbidity risks. Most patients showed symptomatic improvement.

Adult↗

PubMed1992

Changes in myocardial beta-adrenergic receptors during acute rejection of heterotopically transplanted rat hearts.

To evaluate changes of the myocardial beta-adrenergic receptors in acute cardiac graft rejection, the density and binding affinity value of the myocardial beta-adrenergic receptors in heterotopically transplanted rat isografts and allografts were analyzed. Hearts from Fisher rat donors were transplanted either to the Fisher rats (isografts) or to Lewis rats (allografts). Histologic examination of the allografts showed mild to moderate rejection on the seventh and fourteenth days and showed severe rejection on the twenty-first day after transplantation. The density values in the allografts and isografts similarly increased significantly (p < 0.05) above the normal level on the seventh and fourteenth days after transplantation. The density in allografts on the twenty-first day decreased significantly (p < 0.05) below the normal level, while that in isografts remained at the normal level. In contrast, the binding affinity value of myocardial beta-adrenergic receptors in both isografts and allografts did not change after transplantation. These results demonstrated that myocardial beta-adrenergic receptors presented upregulation in mild to moderate rejection, whereas these receptors presented downregulation in severe rejection. The data suggested that downregulation of myocardial beta-adrenergic receptors plays a major role in decreased cardiac contractility during severe rejection, but not during mild and moderate rejection.

Abdomen↗

PubMed1992

[Malfunction of prosthetic valves: pathogenesis and diagnostic measure].

Modality of the malfunction of prosthetic valve often reflects the specific features of its design and materials of the prosthesis. During past 17 years, a total of 499 cases of valve replacements were performed in our institute and among them, 50 cases received redo surgery, in which 52 prosthetic valves were replaced due to their malfunctions. Those replaced prosthetic valves were analyzed in terms of their pathogenesis, onset durations and diagnostic methods of each type of malfunction. The malfunctions included hemolytic anemia, thrombosis or tissue overgrowth and tissue failure of bioprostheses. Hemolytic anemia was experienced in 8 cases with Starr-Edwards (S-E) 2320 (n = 7) and Omni-Science (n = 1) both in the aortic position and those prostheses were replaced at 1-9.6 (mean 4.5) postoperative years (POY). The linearized rate of the complication with the S-E 2320 was 3.0%/patient-years (p-y) and its actuarial event free rate was 62% at 11 POY. Operative findings disclosed cloth wear in 5 and perivalvular leakage in 5 cases. Fourteen Hancock (H) and 3 Angell-Shiley (A-S) bioprostheses experienced tissue failure of valves and they were subjected to reoperation at 3.2-10.0 (mean 6.5) POY. The linearized rates were 4.1%/p-y for H and 4.5%/p-y for A-S with actuarial event free rates at 12 POY of 59 and 56%, respectively. Prosthetic valve thrombosis and/or tissue overgrowth were seen in 17 valves at 1.6-15.1 (mean 9.1) POY.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1992

[Result of surgical treatment of true or dissected thoracic aneurysm: determinants analysis in operative mortality and morbidity].

Between 1986 and 1990, 69 patients underwent surgery either for thoracic aneurysm (27 patients) or aortic dissection (42 patients). Sixty one patients (88%) survived and 8 patients (12%) died after surgery. Main determinants of deaths in 4 patients with true arch aneurysm were bleeding from the sites of aortic clamping or anastomosis and intraoperative severe LOS. Three patients with acute type A dissection died from bleeding due to clamp injury or myocardial ischemia. The cause of death in the patient with chronic type B dissection was associated with brain damage due to hypoxia developed during left heart bypass. Postoperative cardiac, pulmonary, hepatic and renal functions were analyzed in the operative survivors. Cardiac functions were maintained well in all patients except two patients with chronic type A dissection. Four patients, one with true arch aneurysm, 2 with chronic type A and one with chronic type B dissection, required tracheostomy. The mean of maximum total serum bilirubin exceeded 4 mg/dl in the patients with true arch aneurysm, acute and chronic type A dissection. The level of serum creatinine showed slight increase in all patients but prophylactic peritoneal dialysis was performed in one patient with chronic type A dissection. In conclusion, the cause of deaths in most patients with thoracic aneurysm was due to inappropriate operative techniques and circulatory supports during surgery. Without the complication described above, the patients could tolerate surgery well.

Aged↗

PubMed1992

[Postoperative respiratory dysfunction in patients with Stanford type A aortic dissection].

Between 1986 and 1990, 24 patients with Stanford type A dissection (acute; 14, chronic; 10) underwent surgery through median sternotomy. The patients were divided into two groups by a duration of postoperative ICU stay for respiratory care. Six patients in the long-period group stayed in ICU for more than 15 days and 18 patients in the short-period group stayed for less than 15 days after surgery. Acuity of disease, age, sex, operation time, pump time, aortic clamp time, lowest esophageal temperature, amount of blood transfusion, arch manipulation for cerebral perfusion with or without arch reconstruction, occurrence of phrenic nerve palsy and other postoperative complications, postoperative cardiac, hepatic and renal functions were compared between two groups. Conclusions are as follows: 1) Arch manipulation for cerebral perfusion with or without arch reconstruction, phrenic nerve palsy, other complications (pericardial and pleural fluid accumulation, recurrent nerve palsy, postoperative bleeding and coronary spasm) and high serum creatinine level were main factors for prolonged postoperative ICU stay for respiratory care and 2) arch manipulation in the patients with chronic type A aortic dissection induced high incidence of phrenic nerve palsy.

Adult↗

PubMed1992

[Successful post-left ventricular aneurysmectomy left ventricular assist with a centrifugal pump].

A 71-year-old male with a left ventricular aneurysm underwent aneurysmectomy. The patient could be weaned from cardiopulmonary bypass with high-doses of dopamine and dobutamine, followed by immediate left ventricular failure and systemic hypotension. IABP could not be applied to the patient because of the kinked bilateral common iliac arteries. In this condition a centrifugal pump system was connected between left atrium and ascending aorta. With a pump flow of 2 L/min the patient returned to an intensive care unit. After 48 hours of left heart bypass with minimal anticoagulation with systemic heparinization the device could be removed. The patient recovered without any complications, such as thromboembolism, renal failure or mediastinitis. He discharged in fair condition 3 months after the operation.

Aged↗

PubMed1992

[Experience in the treatment of acute fulminating myasthenia gravis].

During past 15 years, 188 myasthenia gravis (MG) patients underwent thymomectomy or thymectomy with extended resection of the adipose tissue around the thymus in our institution. Four of 188 patients (2%) had to be given respiratory support within 2 months after the onset of MG. We defined this MG as the acute fulminating type. There were 2 male and 2 female patients, ranging in age from 22 to 44 years (average, 32.5 years). Three of these patients had thymoma. One of these patients was post-thymomectomy myasthenia gravis and another patient was d-penicillamine induced myasthenia gravis. Two patients admitted on respirator for respiratory crisis. All patients underwent operation within 2 weeks after admission. The duration of respiratory support ranged from 10 to 120 days (mean 44) after operation. The period of the hospital stay ranged from 8 months to 2 years 1 month (mean 1 year 5 months). During acute stage after operation, the patients needed ACTH, steroid, immunosuppressants (azathioprine, Bredinin) and plasma pheresis depending on their severity of myasthenic symptoms. In 2 patients dose of steroid could be reduced without deterioration of the symptoms. They are doing well with small dose of steroid. In one patient plasma pheresis was performed 6 years after thymectomy. Various symptoms due to myasthenia gravis and rheumatoid arthritis has recurred 10 years after thymectomy. The titer of acetylcholine receptor antibody of this patient has been continuing in high level.

Acute Disease↗

PubMed1992

[Effects of coronary artery bypass grafting for patients with totally occluded left anterior descending arteries].

Between April, 1987 and March, 1991, 21 patients with totally occluded left anterior descending arteries (TOLAD) underwent coronary artery bypass grafting (CABG) in our institute. All of them were diagnosed as angina pectoris and 15 (71%) of them have had episodes of myocardial infarction. Graftability of TOLAD was 90% (19/21) and two of the TOLADs were not suitable for CABG because severe atherosclerosis of these arteries were observed intraoperatively. There was no operative death. Short term (1-2 months) patency was 64% (7/11) for saphenous vein grafts (SVG) and 100% (8/8) for left internal thoracic artery grafts (LITA). Left ventricular wall motion assessed by left ventriculography showed impaired regional wall motion in 63% segments of the segment #2, #3 and #6 preoperatively. However, the regional wall with impaired motion decreased to 31% after CABG. Thallium-201 scintigraphy showed impaired perfusion in 62% segments of the left anterior wall, apex and interventricular septum preoperatively. However, the regional wall with impaired perfusion decreased to 42% after CABG. Exercises tolerance assessed by treadmill test was improved from 3.8 +/- 0.7 Mets preoperatively to 6.5 +/- 0.7 Mets with patent coronary bypass grafts. These data suggested that CABG can improve the wall motion of the regions perfused by TOLADs and the LIMA is more suitable than the SVG for CABG to TOLAD.

Constriction, Pathologic↗

PubMed1992

[Separate perfusion of upper and lower body for ruptured thoracoabdominal aortic aneurysm--a case report].

A case of ruptured thoracoabdominal aortic aneurysm was presented. The patient had emergent replacement of thoracoabdominal aorta with an aid of separate perfusion of upper and lower body. The postoperative course was uneventful. It was suggested that separate perfusion of upper and lower body was useful in the patients who require extensive aortic replacement and who are at substantial risk for spinal cord injury.

Aorta, Abdominal↗

PubMed1992

[Surgical treatment of myasthenia gravis associated with Graves's disease].

During past 30 years, we experienced 253 patients who underwent surgery for myasthenia gravis. Among these patients, 9 were associated with Graves' disease. No patients had thymoma. Five patients underwent thymectomy after they had become euthyroid by medical treatment, though four patients required subtotal thyroidectomy before thymectomy. One patient developed myasthenic crisis following thyroidectomy and was treated with respirator for 5 days. But thymectomy was performed without myasthenic crisis in these four patients between 25 days and 60 days after thyroidectomy. They have been doing well and no see-saw phenomenon was presented. Thymectomy is safe and effective even in the patients with Graves's disease, and we recommend to perform it after they become euthyroid by medical or surgical treatment.

Adult↗

PubMed1991

[Serious complication of retrograde perfusion during repair of dissecting aneurysm: compression of the true lumen].

Between 1982 and 1990, 61 patients underwent the repair of dissecting aneurysm. Retrograde perfusion from the unilateral femoral artery were performed for 56 patients and the selective false lumen perfusion occurred in 3 patients. As for those 3 patients, compression of the true lumen and insufficient cerebral perfusion were suspected. Selective cerebral perfusion and antegrade systemic perfusion from the ascending aortic graft were performed. Although 2 patients took uneventful postoperative courses, 1 patient died of massive brain damage. It is very important to accomplish the means to maintain adequate cerebral circulation as soon as possible toward this fetal complication.

Adult↗

PubMed1991

[Analysis of hepatic and renal dysfunction after surgery of thoracic aneurysm].

To analyze causes of postoperative hepatic and renal dysfunction in patients with thoracic aneurysm, we examined 31 patients who survived surgeries and 2 patients died of MOF. The patients were separated into three groups as follows; Cardiopulmonary bypass (CPB) was used for circulatory support in group A (n = 7), CPB and low flow perfusion during open distal anastomosis in group B (n = 13) and temporary bypass or left atrial distal aorta arterial bypass was used in group C (n = 11). Operation time was significantly longer in group A (9.8 hrs) compared with group C (6.1 hrs). Amount of intraoperative blood transfusion was greater in groups A (4980 ml) and B (4860 ml) compared with group C (2320 ml). Postoperative highest total bilirubin level was significantly greater in group A (7.8 mg/dl) than group C (2.5 mg/dl). LDH was higher in groups A (1322 IU/l) and B (1336 IU/l) than group C (991 IU/l). GOT was higher in group B (200 IU/l) than group C (64 IU/l). There were no significant differences in GPT, creatinine and BUN among the three groups. Operation time and amount of intraoperative blood transfusion were positively correlated with postoperative hepatic function parameters. Two patients died of MOF showed severe hepato-renal dysfunction associated with LOS. The results indicate that hypothermic low flow perfusion during open distal anastomosis do not induce hepatic or renal dysfunction, and postoperative hyperbilirubinemia is resulted from bilirubin overload which patients can tolerate well if they are not complicated with MOF.

Aged↗

PubMed1991

[Coronary artery bypass grafting using right gastro-epiploic artery and cholecystectomy].

A 59-year-old male with ischemic heart disease and cholecystolithiasis underwent coronary artery bypass grafting (CABG) using the right gastro-epiploic artery (GEA) and cholecystectomy simultaneously CABG was performed under standard extracorporeal circulation followed by cholecystectomy at the same incision. The opening in the dome of the diaphragm where the pedicle of GEA was brought up was closed with fibrin glue. Then, sternum was closed and cholecystectomy was performed with no elongation of the incision. The postoperative course was uneventful without mediastinitis or other infectious events. The postoperative angiography showed good patency of the GEA graft. Combined CABG using GEA and cholecystectomy is beneficial for the selected patients.

Arteries↗

PubMed1990

Recurrent thymoma in patients with myasthenia gravis.

One hundred sixty-six patients underwent operation for myasthenia gravis between 1977 and 1989. Thirty-eight patients had associated thymoma, registering stages I (n = 17), II (n = 9), III (n = 11), and IVa (n = 1) according to the classification of Masaoka and colleagues. Extended thymectomy was performed on 128 patients without thymoma; thymothymectomy, with resection of the anterior mediastinal fat and tissues adherent to the tumor, was performed in all patients with thymoma. There were no instances of early or late death. Neuromuscular function improved, and clinical myasthenic symptoms stabilized in almost all patients except 2 patients in stage III and 1 patient in stage IVa, who had an exacerbation of the myasthenic symptoms associated with recurrence of thymoma. All the recurrent tumors were on the pleura and could be resected. The suspected cause of recurrence is either dissemination of tumor cells as a result of operative manipulation or undetected disseminated foci that existed at the time of the first operation. The resections of the recurrent invasive thymomas localized on the pleura were easily performed and improved the myasthenic symptoms.

Adult↗

PubMed1990

The effects of 5% carbon dioxide on the quantitative analysis of long-term pathology of the brain after surface hypothermia.

To evaluate the effects of 5% carbon dioxide (CO2) administration for hypothermic circulatory arrest, neurological evaluation and pathological studies were carried out on the canine brain. Twenty-two dogs were assigned to five groups: Group 1: Three dogs without hypothermia were sacrificed as the control group. Group 2: Nine dogs were subjected to surface hypothermia (20 degrees C) under deep ether anesthesia with 100% oxygen (O2) and hyperventilation. Circulatory arrest time was 30 min in Group 2A and 60 min in Group 2B. Group 3: Ten dogs were surface cooled (20 degrees C) under deep ether anesthesia with a 95% O2 and 5% CO2 mixture. Thirty minutes of circulatory arrest was instituted in Group 3A and 60 min in Group 3B. Dogs in Groups 2 and 3 were surface rewarmed and kept alive until they were sacrificed electively 6 or more months later. Results were as follows: (i) Postoperative neurological disturbance was detected in only two dogs in Group 2B. (ii) The percentage of damaged nerve cells among the total nerve cells counted in the cerebral cortex of the frontal lobe was significantly greater in Groups 2A (22.4%), 2B (30.1%), 3A (19.6%), and 3B (22.2%) compared with Group 1 (7.1%). (iii) The number of glia cells per nerve cell in the cerebellar dentate nucleus was significantly higher in Group 2B (27.2) than in Groups 1 (11.8), 2A (16.7), 3A (17.9), and 3B (18.6). (iv) The number of Purkinje cells in a 10-mm length of the cerebellum was markedly reduced to 89 in Group 2B compared with 122, 134, and 117 in Groups 1, 2A, and 3A, respectively. In conclusion, the results of quantitative pathological brain analysis reflected the incidence of postoperative neurological disturbance and suggested that the administration of 5% CO2 could prolong the time limit for circulatory arrest.

Animals↗

PubMed1990

Shape from shading in different frames of reference.

It has often been reported that, in the absence of information about the direction of illumination, people interpret surface convexities and concavities in accordance with the assumption that illumination comes from above. However, 'above' could mean with reference to gravity, the head or the retina. Yonas et al reported that four-year-old infants use the head more than gravity as the frame of reference in interpreting surface relief but that seven-year-olds make about equal use of the two frames of reference. The potency of these two frames of reference when acting separately and when pitted against each other was measured on adult subjects. For all subjects the 'assumption' about the direction of illumination was predominantly with respect to the head. The gravitational frame was used only when the headcentric frame was irrelevant, and then not consistently.

Adult↗

PubMed1989

Effect of donor specific transfusion (DST) is restricted to the rat combination used and closely related with alloantibody in heart transplantation.

The effect of donor specific transfusion (DST) in several donor-recipient combinations was examined using the rat heart transplantation model. In some donor-recipient combinations such as LEW to DA, LEW to ACI, LEW to PVG and PVG to DA, DST pretreatment could induce permanent graft survival (greater than 100 days). But in DA to LEW, ACI to LEW, LEW to BN, BN to LEW, PVG to LEW and BN to DA combinations DST pretreatment had no effect on graft survival. The effect of pre-immunization with several DA antigens (heart, liver, lymph node cells and red blood cells) was examined using the DA to LEW combination in which DST pretreatment was not effective. In no case was permanent graft survival obtained. Alloantibody levels (anti-class I and anti-class I + II, respectively) were analysed at the time of heart transplantation and in the post-transplantation period. The anti-class I antibody levels were low or not detected in rats with surviving grafts, but in the rats which failed to have the prolonged graft survival, anti-class I antibody levels were high. This study showed that the effect of DST was restricted to particular donor-recipient rat combination in the heart transplantation model.

Animals↗