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Biomedical subjects

A Yamaoka

Publications and source records attributed to A Yamaoka.

At least 19 recordsLinked to original sources
PubMed2000

Organ malperfusion in acute aortic dissection.

OBJECTIVE: Organ malperfusion in aortic dissection can precipitate a serious condition. The strategy of treatment for it has been controversial. We have focused on the strategy and outcome of acute aortic dissection with organ malperfusion. SUBJECTS AND METHODS: Between January 1995 and December 1998, 134 acute aortic dissection patients were admitted. There were 73 males (65.4 +/- 8.0 years old) and 61 females (66.7 +/- 7.4 years old). There were 83 patients of Stanford type A, and 51 patients of type B. Of them, 24 patients (17.9%) were complicated by organ malperfusion. The brain was affected in 4, the heart in 5, the spinal cord in 2, the liver in 1, the intestine in 1, the kidney in 4, and the lower extremities in 10 patients. Our management strategy for a patient with malperfusion in acute aortic dissection was that the antecedent operation was initially mandatory, and central grafting was secondarily considered. RESULTS: Refusal of operation or lethal conditions excluded 8 of the 24 patients from operation. An antecedent operation was mandatory in eight of the remaining 16 patients. The overall mortality was 33.3% (8/24 patients), and operative mortality was 31.3% (5/16 patients) in the patients with malperfusion. The overall mortality was 11.8% (13/110 patients), and the operative mortality was 11.1% (9/81 patients) in the patients without malperfusion. CONCLUSION: Organ malperfusion is a major component in the management and treatment of acute aortic dissection. Only an appropriate strategy and therapy could result in a satisfactory outcome.

Acute Disease↗
PubMed2000

[Simultaneous operation for lung tumor and cardiovascular disease].

Successful simultaneous operation for lung tumor and cardiovascular disease was performed in three cases. A 76-year-old man with stage I lung cancer and ischemic heart disease underwent a partial lobectomy following single coronary artery bypass grafting through a median sternotomy. A 62-year-old man with stage I suspected lung cancer and thoracic aortic aneurysm underwent a partial segmentectomy before aneurysmectomy and patch closure using vascular prosthesis through a left posterolateral thoracotomy. These two cases were performed under extracorporeal circulation. A 69-year-old man with bronchogenic carcinoma and abdominal aortic aneurysm underwent a left upper lobectomy with standard lympho node dissection following aneurysmectomy and grafting using vascular prosthesis. As a simultaneous procedure, limited operation for lung tumor, especially for stage I non-small cell lung cancer, is acceptable for cases in using extracorporeal circulation. On the other hand, except emergency ruptured cases of abdominal aortic aneurysm, standard radical operation for lung cancer as a simultaneous procedure is preferred for cases such as lung cancer accompanied with abdominal aortic aneurysm without extracorporeal circulation.

Aged↗
PubMed1999

Clinical experience of 473 patients with the omnicarbon prosthetic heart valve.

BACKGROUND AND AIM OF THE STUDY: The long-term clinical experience of patients receiving Omnicarbon heart valve prostheses between January 1985 and December 1996 was investigated. METHODS: In total, 473 patients (255 males, 218 females; mean age 57.5 +/- 10.1 years (range: 20n-73 years) received 523 prostheses. These included 253 mitral (MVR), 170 atrial (AVR) and 50 double (DVR) valve replacements. RESULTS: The 30-day mortality rate was 4.7% (n = 22); in addition eight patients died more than 30 days after surgery, but during the same hospital stay. Mean follow up was 3.9 years (maximum 11 years and 7 months). Cumulative follow up was 1,750.1 patient-years (pt-yr); follow up was 97.5% complete. Among 39 late deaths, 20 were valve-related (seven cerebral infarction, seven cerebral bleeding, six endocarditis) and four cardiac-related. The overall five-year cumulative survival rate (excluding early mortality) was 90.2 +/- 11.7% (MVR 88.0 +/- 2.5%, AVR 93.1 +/- 2.3%, DVR 93.7 +/- 4.8%). At 10 years, the overall survival rate was 76.4 +/- 7.7%. Valve-related complications included thromboembolism (n = 13, 0.7%/pt-yr), anticoagulation-related hemorrhage (n = 12, 0.7%/pt-yr) and endocarditis (n = 7, 0.4%/pt-yr). Neither mechanical failure nor clinical hemolysis was observed. The overall valve-related event-free rate after five years was 89.3 +/- 2.0% (MVR 89.8 +/- 2.4%, AVR 93.5 +/- 2.6%, DVR 89.4 +/- 5.7%) and after 10 years it was 87.6 +/- 2.6% (MVR 85.4 +/- 3.7%, AVR 93.5 +/- 2.6%, DVR 82.5 +/-10.1%). CONCLUSIONS: These long-term results with the Omnicarbon valve are excellent; especially satisfactory results were achieved in terms of the low rate of thromboembolic complication.

Adult↗
PubMed1998

[Preoperative autologous donation of blood in cardiac surgery--age related factors].

We have studied influence of the age related factors on preoperative autologous donation (PAD) of blood in cardic surgery. PAD was undertaken in 246 cases of elective cardiac surgery by means of simple or leap-frog method, starting at approximately 4.5 weeks before operation. It provided 1726 ml of autologous blood storage on the average. Sorting the patients into three groups with age, leading surgical procedures were as follows: closure of the atrial septal defect (ASD) in teen 30s (group L, n = 51), aortic valve replacement (AVR) or mitral valve replacement (MVR) in 40s-50s (group M, n = 83) and 60s and over (group H, n = 112). Coronary artery bypass grafting (CABG) was more common in group H. Percent-freedom from allogeneic blood transfusion was 82.3% in group L, 80.7% in group M and 61.6% in group H, respectively (p < 0.05; L, M vs. H), donated blood volume in group H was significantly less than that of group M (p < 0.05, M: 1987 +/- 63, H: 1610 +/- 60 ml), because blood volume and hemoglobin level before donation tended to be less in group H. Each group did not differ in blood loss during and after operation, which showed a significant positive correlation with operation time and cardiopulmonary bypass (CPB) time. Comparing factors in ASD, CPB time was relatively long, and postoperative blood loss was significantly larger in group H (p < 0.05; L: 432 +/- 71 ml, M: 369 +/- 34 ml, H: 754 +/- 124 ml). This finding suggests that the secondary lesions in age ASD cases adversely affected hemostasis. As to AVR, MVR and CABG, there were no differences in these factors but donated blood volume among three groups. We conclude that elderly patient (60s and over) tends to necessitate allogeneic blood transfusion in cardiac surgery because of the insufficient PAD. Earlier commencement of PAD or concomitant application of erythropoietin will improve this situation.

Adolescent↗
PubMed1998

Malignant melanoma of the chest wall with an unknown primary lesion.

We report herein the case of a 66-year-old man who underwent resection and reconstruction of the chest wall due to the presence of a malignant melanoma without a detectable primary lesion. The patient was discharged in good condition after receiving chemotherapy but eventually died of multiple bone metastases 2 years after surgery. Throughout the postoperative course, there were no specific symptoms or findings suggesting the presence of a primary lesion. It was considered likely that the primary tumor was resolved by spontaneous regression after chest wall metastasis had been established.

Aged↗
PubMed1998

Two types of initial ocular manifestations in intraocular-central nervous system lymphoma.

PURPOSE: To study initial ocular manifestations of ocular-central nervous system (CNS) lymphoma. METHODS: The authors reviewed medical records of 10 consecutive patients with intraocular-CNS lymphoma seen at Okayama University Hospital during 16 years from 1981 to 1996. RESULTS: Three patients showed only vitreous opacity as an initial sign, whereas five other patients had typical yellowish-white infiltrates at the sub-retinal pigment epithelial (sub-RPE) level without vitreous opacity. Both manifestations were found in two patients. In seven patients, ocular symptoms developed first, followed by brain lesions. In contrast, in three patients the initial presentation was brain tumor, for which they received chemotherapy; subsequently, vitreous opacity without sub-RPE infiltrates developed. The diagnosis was made by vitrectomy in four patients, three of whom had also undergone brain biopsy; by aqueous tap in one; and by brain biopsy in one. The other four patients were diagnosed clinically, and one of them was confirmed later to have lymphoma by autopsy. CONCLUSIONS: The initial ocular manifestations of intraocular-CNS lymphoma were of two types, sub-RPE infiltrates and vitreous opacity. Keeping these two manifestations in mind will help physicians consider a diagnosis of intraocular-CNS lymphoma earlier.

Adult↗
PubMed1998

Experimental study of cardiac lymph dynamics and edema formation in ischemia/reperfusion injury--with reference to the effect of hyaluronidase.

This study is designed to evaluate the effect of hyaluronidase on the canine myocardial edema derived from ischemia/reperfusion injury. The mongrel dog's heart received 90 minutes of ischemia under cardiopulmonary bypass consisting of 30 minutes of normothermia alone and 60 minutes of hypothermia with cardioplegic arrest. Reperfusion for 60 minutes was added thereafter. Two kinds of cardioplegic solution, 4 degrees C St. Thomas' Hospital solution with or without 3000 units/L of hyaluronidase, were prepared. The solution was given antegradely every 30 minutes during cardioplegic arrest. Cardiac lymph was collected continuously from the afferent duct of the cardiac lymph node by cannulation. Hyaluronidase in the cardioplegic solution increased cardiac lymph volume significantly and improved postischemic recovery of cardiac function. A high level of adenosine triphosphate was maintained at that time. The myocardial water content at the end of reperfusion revealed a minimum increase with hyaluronidase use. Active drainage of cardiac lymph by hyaluronidase alleviates the myocardial edema formation, thereby preserving cardiac function.

Adenosine Triphosphate↗
PubMed1997

[Temporary extracorporeal axillofemoral venous bypass--a beneficial device in operation for superior vena caval syndrome due to intrathoracic malignancies].

Life-threatening complications can occur unexpectedly during general anesthesia in operations for superior vena caval (SVC) syndrome due to intrathoracic tumors. To prevent such sequelae, we have placed a temporary extracorporeal axillofemoral venous bypass graft with satisfactory results. In six patients (malignant mediastinal tumor, four; lung cancer, two), under local anesthesia before induction of general one, the cannulas, each appropriately sized in accordance with the diameter of the axillary and femoral veins, were directly introduced into the corresponding veins after systemic heparinization. The two cannulas were connected with a tube to which a side arm, which was usually clamped, was connected. The venous pressure of the internal jugular vein decreased immediately after establishment of the temporary bypass in all patients. The symptoms that accompanied SVC syndrome did not worsen and the life-threatening complications at the time of induction of general anesthesia were avoided with this procedure. In each case cardiopulmonary bypass on stand-by was unnecessary at this time. Venous bypass grafting with vascular prostheses were mainly performed under cardiopulmonary bypass, which was required for such operative procedures. In three patients the side arms were used for part of the venous drainage during cardiopulmonary bypass. The SVC syndrome instantly disappeared after operations in all patients including one in hospital death. No serious complications related to the temporary bypass procedure have been observed. This temporary bypass procedure has several advantages. It can be safely performed under local anesthesia with no special technique for the cannulation. Venous blood naturally drains from the upper part to the lower part of the body by pressure gradient, that warrants the safe induction of general anesthesia and ensuing operative procedures. The side arm is available for venous drainage during cardiopulmonary bypass. There are no serious complications related to the bypass procedure. Thus this temporary bypass is recommended as a life-saving and auxiliary device in urgent operations for acute progressive SVC syndrome with symptoms of cerebral edema and upper airway obstruction due to intrathoracic malignancies.

Adult↗
PubMed1996

Portal vein obstruction accompanied by intrahepatic stones.

This study was conducted to clarify the pathogenesis of portal vein obstruction (PVO) associated with intrahepatic stones. Five cases with PVO and intrahepatic stones were studied retrospectively. The coincidence rate of PVO in intrahepatic stones was 5.8% (5 of 86 cases), and that of intrahepatic stones in PVO, 45.5% (5 of 11 cases). All cases had one or more symptoms of cholangitis, such as high-grade fever, abdominal pain, and jaundice prior to diagnosis of PVO. The portal vein was occluded at the main trunk in 4 and in the left branch in 1. Intrahepatic stones were found in bilateral hepatic lobes in 3 and in the left lobe in 2. Numerous calcium bilirubinate stones were packed in dilatated intrahepatic bile ducts of an excised specimen of the liver. Microscopically, arterial structures could be seen, but the portal vein ceased to be evident about the involved bile duct. Based on the results of this study, persistent cholangitis and packed gallstones were concluded essential to the development of PVO accompanied by intrahepatic stones.

Adult↗
PubMed1996

[Usefulness of Dumon-type endotracheal stent for left main bronchial obstruction caused by thoracic aortic aneurysm--a case report].

We used a Dumon-type endotracheal stent for left main bronchial stenosis occurred after the operation of combined true and Type III dissecant aneurysm. A 65-year-old man with acute Type III dissection with true thoracic aneurysm was operated on by means of arch replacement with thoracic aortic replacement. He complained of dyspnea and the respirator support was not able to discontinued. The cause of dyspnea was oppression of the left main bronchus with remnant thoracic dissecting aneurysm together with a hematoma. A Dumon-type stent was successfully inserted into the left main bronchus under bronchoscopic guide via tracheostomy. It is a choice of conservative therapy after major surgery such as operation of thoracic aneurysm to relieve the bronchial obstruction.

Aged↗
PubMed1996

[Surgical results of valve replacement with porcine bioprostheses].

We evaluated the 80 cases of porcine valve replacement, accomplished between April 1975 and December 1980. There were 48 males and 32 females aged between 16 and 60 years old with a mean of 37.4 +/- 11.4. Ten patients underwent aortic valve replacement (AVR), 63 mitral valve (MVR), and 7 AVR plus MVR. Twenty-seven Hancock valves (H) were implanted in aortic (3) and mitral (24) position and 61 Carpentier-Edwards valves (CE) were used in aortic (14), mitral (46), and tricuspid (1) position. The mean duration of follow-up was 9.3 years (0.2-19.2 years) and cumulative follow-up was 747.2 patient years (py). The late mortality was 3.3%/py (25 patients). Actuarial survival rates for all patients at 10 and 15 years were 67%, and 49% respectively. The linearized rates (LR) of structural valve deterioration (SVD) was 7.0%/py. The freedom from SVD for all patients at 10, and 15 years were 47.1%, and 12.4% respectively. There were no differences of free rates of SVD between H and CE. between valve sites implated, and among age at operation. The incidence of occurrence of SVD was gradually increased 6 years after operation. The LR of thromboembolism (TE), anticoagulant-related hemorrhage (ACH), prosthetic valve endocarditis (PVE), nonfunctional valve dysfunction (NVD), and reoperation (RO) were 0.7%/py, 0.1%/py, 0.3%/py, 0.1%/py and 7.4%/py, respectively. The freedom from TE, ACH, PVE, NVD, and RO for all patients at 15 years were 91.3%, 98.1%, 95.6%, 80%, and 6.5%, respectively. The surgical results of glutaraldehyde-preserved porcine bioprostheses was excellent during the first 5 years after operation. A high incidence of SVD has been occurred thereafter. According the indication for valve replacement with bioprotheses is now strictly limited for elderly, child bearing female case, contraindition for therapy of anticoagulants, and some social condition.

Adolescent↗
PubMed1996

[Surgical results of valve replacement with the Björk-Shiley tilting disc valves].

We evaluated the Björk-Shiley tilting-disc (BS) valve replacement up to the longest duration for about 12 years. The study was started in November 1982 and ended in September 1991. There were total number of 206 with 117 males and 89 females aged between 18 and 71 with a mean of 51.6. Eighty three patients had isolated aortic valve replacement (AVR), 92 had isolated mitral valve replacement (MVR), and 31 had AVR plus MVR. One hundred and fourteen spherical-disc valves were replaced in the aortic, 112 spherical and 11 monostrut in the mitral position. The mean duration of follow up was 6.5 years for a total of 1330.6 patient years (PY). Forty-one patients (3.8%/PY) died later, and 14 out of 41 died of valve-related complications. Actuarial survival rates for all, AVR, MVR and DVR at 10 years after operation were 71.2%, 73.5%, 73.9% and 55.4%, respectively. The linearized rates of thromboembolism (TE), thrombosed valve (TV), anticoagulant-related hemorrhage (ACH), prosthetic valve endocarditis (PVE), hemolysis (H), and reoperation (RO) were 1.2%/PY, 0.2%/PY, 0.7%/PY, 0.2%/PY, 0.1%/PY, and 0.2%/PY, respectively. The rates of freedom from TE, TV, ACH, PVE, H, and RO and 10 years after operation were 83.5%, 98.5%, 94.0%, 98.4%, 99.0% and 95.6%, respectively. The major causes of postoperative mortality and morbidity were TE, TV, and ACH. One hundred and fifty-six out of 161 patients showed an improvement in NYHA functional class post operatively. The surgical results of valve replacement with the BS valve was excellent and acceptable one. Intensive management with a special reference of anticoagulant therapy is necessary for a long-term management of the patients with mechanical valve replacement.

Adolescent↗
PubMed1995

A human lectin, galectin-3 (epsilon bp/Mac-2), stimulates superoxide production by neutrophils.

A family of soluble animal lectins, galectins, with beta-galactoside-binding activity, is gaining increased attention. One member of this family, galectin-3, has been previously designated by this group as epsilon bp, for its IgE-binding activity. On the basis of the saccharide specificity and other biochemical characteristics of epsilon bp, it is possible that this lectin could have an important extracellular modulatory role, functioning through recognition of critical cell surface glycoproteins on many cell types. We present evidence here that recombinant human epsilon bp activates human neutrophils in a dose-dependent manner as demonstrated by superoxide production. The observed activity is dependent on the lectin property of epsilon bp intrinsic to its carboxyl-terminal domain, as it could be inhibited effectively by lactose, a known saccharide ligand of epsilon bp. However, the amino-terminal domain is also necessary for the observed activity, as epsilon bp-C (the carboxyl-terminal domain fragment) is devoid of neutrophil-activating activity, even though it retains the carbohydrate-binding property. Affinity purification of lysates from cell surface-radio-iodinated neutrophils revealed two major protein bands of M(r) 115,000 and M(r) 180,000 that are recognized by epsilon bp and preliminary data suggested that one of these proteins is NCA-160, a human carcinoembryonic Ag-related glycoprotein. This study thus lends further support to our view of an extracellular function for epsilon bp and suggests that this protein has an important role in inflammation and host defense through modulating the function of neutrophils.

Antigens, Differentiation↗
PubMed1995

Cementum-impregnated gelatine membrane: its effect on periodontal tissue regeneration.

This study was designed to evaluate the ability of cementum-impregnated gelatine membranes (CGM) to stimulate regeneration of periodontal ligament following surgery. Three monkeys with no periodontal disease were used. Following flap elevation, recession type defects were created on the buccal side of maxillary lateral incisors and second premolars, and roots were subsequently planed. Experimental sites received CGM at approximately 2-3 mm below the cementoenamel junction while control sites received gelatine membrane (GM) free of cementum. Wounds were allowed to heal for 3 weeks, during which time daily plaque control measures were maintained. Tissues prepared from sacrificed animals revealed that experimental specimens exhibited formation of new cementum, new bone, and periodontal ligament. Control specimens exhibited connective tissue adhesion without either new cementum or significant new bone formation. Histometric analysis showed that the average vertical growth of cementum (NC) and bone (NB) at experimental sites were 3.48 +/- 0.29 and 0.64 +/- 0.43 mm, respectively. At the control sites the corresponding results were NC = 0.09 +/- 0.03 and NB = 0.06 +/- 0.28. It was concluded that placement of CGM resulted in significantly greater postsurgical cementum and bone formation than that of GM alone.

Animals↗
PubMed1995

[Lung cancer manifested as cardiac tamponade: a case report].

A case of lung cancer manifested as cardiac tamponade was reported. A 64-year-old male had anterior chest pain and dyspnea. A chest X-ray films showed an enlarged heart with a solitary round shadow in the left lung hilus. Echocardiogram disclosed a large amount of pericardial effusion. Emergency pericardiectomy with drainage was accomplished. The patient lived for 8 months without effusion accumulation. Histologically adenocarcinoma of the lung with prominent lymph nodes metastases was disclosed. Surgical decompression such as pericardiectomy or pericardial fenestration is a valuable selection in the treatment of pericardial effusion and tamponade.

Adenocarcinoma↗
PubMed1995

[Transient tracheal obstruction during surgical correction of scoliosis in a patient with Marfan's syndrome].

A 13-yr-old male with Marfan's syndrome underwent surgical correction of severe scoliosis. He had not manifested dyspnea previously in any position. Under anesthesia with thiamylal and vecuronium, his trachea was intubated with a reinforced endotracheal tube without any difficulty. Anesthesia was maintained with nitrous oxide and fentanyl, 8 micrograms.kg-1. The patient was placed in a prone position. Thirty min after the start of operation, when orthopedists compressed the thoracic vertebrae vertically, positive pressure ventilation became impossible abruptly, even with a high airway pressure. Three min later, ventilation became possible after cessation of compression and by mouth-to-tube insufflation. SpO2 monitored with a pulse oximeter recovered immediately from 61% to 99%. A capnogram showed a lengthy retardation of an inspiratory phase. Emergency fibreoptic bronchoscopy revealed that the trachea had been compressed vertically; the compression was reduced by moving the chest supporters laterally. After the apneic episode, the operation continued uneventfully, and he was discharged a month later. A severe deformity of the thorax due to severe scoliosis and weak tracheal tissue due to connective tissue defect caused partial tracheal compression before the surgery, and made his trachea susceptible to complete obstruction by vertical external compression on the thorax. Patients with Marfan's syndrome and scoliosis should have careful preoperative airway evaluation. The selection and positioning of endotracheal tubes should be done with care. During surgery, the patient's body position and the condition of the trachea should be checked frequently. Capnography and fiberoptic bronchoscopy seem to be mandatory for early detection of tracheal stenosis and prevention of tracheal obstruction.

Adolescent↗