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Biomedical subjects

H Murayama

Publications and source records attributed to H Murayama.

At least 127 records · Page 7Linked to original sources
PubMed1991

[Response analysis for an approximate 3-D image reconstruction in cone-beam SPECT].

Cone-beam Single Photon Emission Computed Tomography (SPECT) offers the potential for a large increase in sensitivity as compared with parallel hole or fan-beam collimation. Three-dimensional image reconstruction was approximately accomplished by backprojecting filtered projections using a two-dimensional fan-beam algorithm. The cone-beam projection data were formed from mathematical phantoms as analytically derived line integrals of the density. In order to reduce the processing time, the filtered projections were backprojected into each planes parallel to the circle on which the focal point moved. Discrepancy of source position and degradation of resolution were investigated by computer simulation in three-dimensional image space. The obtained results suggest that, the nearer to the central plane or the axis of rotation, the less image degradation is performed. By introducing a parameter of angular difference between the focal point and fixed point in the image space during rotation, degradation of the reconstructed image can be estimated for any cone-beam SPECT system.

Algorithms↗
PubMed1991

[A case of successful surgical treatment of recrudescent Stanford type A--acute dissection after early thrombogenic closure of dissecting lumen].

A 53-year-old woman was hospitalized with acute chest pain. A CT scan was demonstrated acute type A aortic dissection. The dissecting lumen was already closed with thrombus. A digital subtraction angiography was performed. It showed no intimal tear and a normal aortic figure. She received the medical treatment. On the fourteenth day after her admission, her both femoral arterial pulses were not palpable. A CT scan and an angiogram were performed. The new intimal tear in the ascending aorta was made, and pericardial effusion appeared. With the use of a ringed interluminal graft, an emergency operation was performed. She was discharged in good health. Some cases of early thrombogenic closure of the dissecting lumen in acute aortic dissection were reported. In a few of them, a new intimal tear developed and they lapsed into the recrudescent acute dissection. Thus, more careful medical follow up is necessary in these cases.

Acute Disease↗
PubMed1991

[Clinical experience of the Greenfield filter--especially about tilting and distal migration of the filters].

Since December 1985, we used Greenfield filter in 8 patients to prevent pulmonary embolism. Mean follow-up period was 42 month. Recurrence of pulmonary embolism was suspected in one patient after perfusion lung scan. Another patient died from other reasons. Occlusion of the inferior vena cava was not suspected in any patient clinically. Tilting and distal migration of the filters occurred frequently. 3 filters tilted greater than 5 degrees compared with the position immediately after their placement. 5 filters migrated distally more than half the length of a lumbar vertebra. Although there was no severe complications in our series, we should pay attention especially to the position and angle of the filters, since an extreme tilting position of the filter could be a possible cause of serious complications.

Adult↗
PubMed1991

[Two reoperative cases of annuloaortic ectasia with Cabrol's method].

Two reoperative cases of annuloaortic ectasia are reported. Since they have problems such as adhesion and friability of tissues, bleeding from each anastomosed sites must be watched carefully. Especially, anastomoses of aortic annulus and the composite graft, coronary ostia and the interposed conduit are important. Appropriate anastomosis of aortic annulus needs flexibility at the proximal edge of the composite graft. It can be achieved by sewing Björk-Shiley prosthetic valve about 5 mm distant from the proximal edge of the composite graft. Cabrol's method is good for anastomoses of coronary ostia because easily visualized and less stressed anastomoses can be performed. Therefore Cabrol's method with flexible edge of the composite graft at the proximal site is a useful technique in the reoperation of annuloaortic ectasia.

Anastomosis, Surgical↗
PubMed1991

[A case report of early prosthetic valve endocarditis due to methicillin resistant Staphylococcus aureus infection--an experience of intraatrial implantation of mitral prosthesis with a Gore-Tex flange].

A 60-year-old female with mitral stenosis developed prosthetic valve endocarditis due to methicillin resistant staphylococcus aureus septicemia 3 weeks after mitral valve replacement. In vitro test disclosed susceptibility to minocycline and clindamycin. Despite large amount of intravenous administration, progressive heart failure due to massive perivalvular leakage occurred as a consequence of persisting infection. An emergent operation revealed valve detachment of the posterior portion resulting from ring abscess formation. A mitral prosthesis with a Gore-Tex flange was implanted partially in the left atrium just above the mitral ring and sutured to the atrial wall. Postoperative relapse was not detected even after discontinuing antibiotics. Prosthetic valve endocarditis due to methicillin resistant staphylococcus aureus is highly resistant to antibiotic therapy and likely to develop valve ring abscess. Prompt surgical treatment is mandatory in this situation.

Endocarditis, Bacterial↗
PubMed1990

Changes in gastric mucosa that antedate gastric carcinoma.

Endoscopic biopsy specimens of the gastric mucosa from 13 patients who were found at follow-up examination to have gastric carcinoma were compared for abnormal histologic features, type of intestinal metaplasia, and presence of immunoreactive carcinoembryonic antigen (CEA), with specimens from 40 tumor-free controls. Villus-like changes and angular infolding, cytologic nuclear pleomorphism, distinct nuclear border, irregular thickness of the nuclear membrane, irregular chromatin clumping, prominent nucleoli, and distinct nucleoli were manifestations of the carcinoma group. Angular infolding, distinct nuclear border, irregular thickness of the nuclear membrane, and distinct nucleoli were also observed in the latent stage before detection of carcinoma. The individual features, however, lacked specificity. Histochemically, a IIB subtype of intestinal metaplasia, and immunoreactive CEA in the cytoplasm of foveolar epithelium appeared exclusively in the patients with carcinoma. These findings indicate that the gastric epithelium of patients with gastric carcinoma tends to be morphologically and histochemically abnormal even before the recognition of classical dysplasia. This can be described as abnormal epithelium and is believed to provide the soil on which gastric carcinoma develops.

Adolescent↗
PubMed1990

Hereditary antithrombin III deficiency with a superior sagittal sinus thrombosis: evidence for a possible mutation starting in the mother of the propositus.

A patient with a superior sagittal sinus thrombosis (SSST) which occurred during the postpartum period is reported. Coagulation studies revealed persistently decreased antithrombin III (AT III) activity. Studies of AT III activity in her family revealed a hereditary AT III deficiency. Since AT III activity was normal in the grandparents of the propositus, the disorder in this family appears to be due to a spontaneous mutation occurring in the mother of the propositus.

Adult↗
PubMed1990

Comparison of coronary hemodynamics in patients with internal mammary artery and saphenous vein coronary artery bypass grafts: a noninvasive approach using combined two-dimensional and Doppler echocardiography.

Blood flow in bypass grafts and recipient left anterior descending coronary arteries was evaluated with combined two-dimensional and Doppler echocardiography in 15 patients with an internal mammary artery graft and in 24 patients with a saphenous vein graft. Comparative studies of coronary hemodynamics were also performed regarding these two different grafting techniques. The graft vessel was detected in 11 (79%) of 14 patients with an internal mammary artery graft and in 20 (87%) of 23 with a saphenous vein graft. The recipient left anterior descending coronary artery was detected in 10 (67%) of the former group and 17 (71%) of the latter. The blood flow patterns obtained were generally biphasic, consisting of systolic and diastolic phases with higher velocity during diastole. The maximal diastolic flow velocity in internal mammary artery grafts was much higher than that in saphenous vein grafts. In patients with an internal mammary artery graft, the flow pattern characteristics within the recipient coronary artery were quite similar to those within the arterial graft, and flow velocities within the recipient coronary artery and the arterial graft were quantitatively almost identical. This outcome may contribute to the long-term patency seen in internal mammary artery grafts. On the other hand, the flow velocity in saphenous vein grafts was fairly low throughout the cardiac cycle. Flow velocity in the recipient coronary artery in patients with a saphenous vein graft was accelerated only in early diastole. As a result, the recipient coronary artery flow pattern and velocity differed substantially from those in the saphenous vein graft.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Flow Velocity↗
PubMed1990

[Surgical therapy for WPW syndrome combined with paroxysmal atrial tachycardia].

A 47-years old man presented with life-threatening paroxysmal supraventricular tachycardia. Electrophysiological study revealed both paroxysmal atrial tachycardia and atrioventricular reentrant tachycardia. The earliest site of activation during paroxysmal atrial tachycardia was located on the cranial portion of the left atrium and just behind the aorta. The atrioventricular accessory passway was located at the posterolateral wall of the left ventricle. Cryosurgical ablation was performed to the cranial portion of the left atrium and the accessory passway was interrupted from inside of the left atrium under the cardiopulmonary bypass. In the postoperative electrophysiological study, neither atrial tachycardia nor atrioventricular reentrant tachycardias was inducible. Since then he has never experienced tachycardia attack for one year.

Cryosurgery↗
PubMed1990

[Surgical treatment of inflammatory abdominal aortic aneurysm].

A 53-year-old man was hospitalized with chronic abdominal pain. A CT scan was performed and demonstrated an aortic aneurysm surrounded by a soft tissue mantle. In the laparotomy, extensive fibrotic adhesions between the aneurysm and the duodenum were discovered. This made mobilization of the duodenum and the left renal vein difficult. The aortic wall was white, thickened, and surrounded with dense fibrous tissue. The aneurysm was replaced by a Dacron graft. Histology of the fibrous tissue showed the features of chronic inflammation. He had no abdominal pain after the operation, and he was discharged in good health. In the preoperative diagnosis of inflammatory aneurysms, the CT scan is useful. We are of the opinion that the preferred treatment for inflammatory aneurysm is aneurysmectomy (or aneurysmorrhaphy) plus grafting.

Aorta, Abdominal↗
PubMed1989

Fibrinogen Sapporo: dysfibrinogenemia characterized by the replacement of A alpha arginine-16 by histidine resulting in the delayed release of fibrinopeptide A by thrombin.

Congenital dysfibrinogenemia was found in a 60-year-old asymptomatic female and her daughter. Purified fibrinogen derived from the propositus, apparently a heterozygote for the abnormality, characteristically showed delayed but complete release of fibrinopeptide A upon digestion with thrombin but its defective release by Ancrod, a snake venom enzyme, from half of her fibrinogen molecules. This congenital dysfibrinogenemia with an A alpha arginine (Arg) to histidine (His) substitution was tentatively designated as fibrinogen Sapporo. Although this type of abnormal fibrinogen had been identified among Caucasians, no such cases have so far been reported in Japan.

Female↗
PubMed1989

[Radioimmunodetection of colorectal cancer, using anti-CEA monoclonal antibodies].

Aiming at radioimmunodetection of colorectal cancer, anti-CEA monoclonal antibodies (CEA102) were produced by immunization with purified CEA. CEA102 showed high specificity with colorectal cancer by mixed hemadsorption assay and immunoperoxidase technique. The antigen detected by CEA102 was confirmed to be carcinoembryonic antigen (CEA) and its molecular weight was estimated to be ca. 180,000 by biochemical analysis. The in vivo study using nude mice grafted a human colorectal cancer or a human malignant melanoma showed greater accumulation of 125I-labeled CEA102 in CEA-positive colorectal cancer than in nude mouse tissues and CEA-negative malignant melanoma. Moreover we successfully obtained scans with good localization of the grafted colorectal cancer on FCR (Fuji Computed Radiography). Using 131I-labeled CEA102 liver metastasis in the patient with colorectal cancer was successfully detected by external scanning with gamma-camera. These results suggest that radiolabeled CEA102 is useful for the detection of colorectal cancer.

Aged↗
PubMed1989

[Alteration of phenotype, morphology and drug sensitivity in colon cancer cell lines under various culture conditions].

Thirteen colorectal cancer cell lines were established from 120 fresh colon cancer specimens. Expression of colon cancer-related antigens and blood group-related antigens on these cell lines were evaluated by Mixed Hemadsorption test (MHA) and Immune Adherence test (IA). The results were compared with the results of immunohistological analysis of the antigen expression in sections of the original tissues, and deletions of several blood group-related antigens in cell lines were observed. Colon cancer cell line HT-29, cultured in different lots of FCS or in different types of serum-free medium showed various antigen expression, suggesting the effect of culture medium on phenotypic expression. In glucose-free medium, HT-29 cells showed the characteristic "dome formation" which is typical of enterocytic differentiation forming brush borders in such cells. HT-29 cells cultured on bovine corneal endothelial extracellular matrix (BCE-ECM) coated plates showed similar enterocytic changes under phase-contrast microscope. Also, irradiated HT-29 cells cultured under 8-Azaguanine containing medium retained their strong resistance to 8-Azaguanine. These results suggest that these cancer cell lines might alter their phenotype, morphology, differentiation, growth pattern and drug sensitivity depending on the culture environment.

Antigens, Neoplasm↗
PubMed1989

Very well differentiated adenocarcinoma of the colon: a case report.

A 47-year-old woman with chronic colitis was found to have a sessile tumor at the hepatic flexure of the colon. An endoscopic biopsy revealed no aytpia, but surgery was performed since, in view of the tumor's size, malignancy could not be ruled out. A tumor measuring 3 x 2 x 1.5 cm was found in the resected specimen. The tumor exhibited quite unusual histologic features, showing invasive, moderately atypical glands forming mucin-filled cysts, very similar to those seen in colitis cystica profunda, under pseudopolypoid mucosa covered by non-atypical glandular epithelial cells. The extension of glandular elements into the pericolonic fatty tissue, and the intermingling of anaplastic microglands led to a final diagnosis of adenocarcinoma. In a case such as this, it is very difficult to evaluate cancerous tissue by endoscopic biopsy, even with an amount of tissue adequate for histologic examination.

Adenocarcinoma↗