Search PubMed⌕ Search

Biomedical subjects

A Shimazu

Publications and source records attributed to A Shimazu.

At least 73 records · Page 4Linked to original sources
PubMed1990

Reverse triiodothyronine nuclear binding in rat brain.

Reverse triiodothyronine (rT3) had been believed biologically inactive, but recently we demonstrated nuclear binding sites for rT3 in human placenta. In this study we examined rT3 binding sites in rat brain. Male Wistar normal rats aged 2, 4 and 9 weeks were killed and the brain was removed for rT3 binding assay. In another series, male Wistar rats weighing about 40g were divided into two groups: group 1 (rickets group), kept on our original rachitogenic diet and group 2, kept on standard diet. After 28 days on either diet they were killed and the brain was removed for assay. Cerebral nuclear protein was extracted with 0.4M KCl buffer. In normal 2 week-old rats specific binding sites for rT3 were detected in all parts of the brain, but at 7 weeks of age the density of the binding sites was decreased and at 9 weeks it is almost 0. Scatchard analysis performed in rachitic rats showed a curvilinear pattern, suggesting two sets of receptors existing in brain tissue; in cerebral cortex one with a association constant (Ka) of 1.07 X 10(8)M-1 and a limited capacity (Bmax) of 0.75 X 10(-15) moles/mg tissue and the other with Ka = 4.93 X 10(6), Bmax = 12.1 X 10(-15), and in thalamus including hypothalamus, one with Ka = 1.00 X 10(8), Bmax = 1.00 X 10(-15) and the other with Ka = 4.57 X 10(6) and Bmax = 18.6 X 10(-15).

Animals↗
PubMed1989

Use of a new stapling instrument for permanent occlusion of the aorta in the surgical procedure for thromboexclusion.

Permanent aortic occlusion is required in the surgical procedures for the flow reversal and thromboexclusion technique and also for the permanent exclusion of aneurysms of the thoracic aorta. We have designed a stapling instrument for the permanent occlusion of the aorta and have used it in 5 patients with aortic dissections and 2 patients with aneurysms of the thoracic aorta. This report describes our newly designed surgical stapler for the closure of the aorta with 2 case reports.

Aortic Dissection↗
PubMed1989

Hypertrophy and calcification of rabbit permanent chondrocytes in pelleted cultures: synthesis of alkaline phosphatase and 1,25-dihydroxycholecalciferol receptor.

Cartilage calcification at specific sites is a key event that leads to skeletal development and growth. To obtain insights into the control of cartilage calcification, we examined whether cells distributed in permanent cartilage regions might have the ability to express the calcification-related phenotype in a permissive environment. Chondrocytes were isolated from the permanent and growth plate cartilages of 4-week-old rabbit ribs. They were seeded as a pelleted mass in a centrifuge tube and cultured in Eagle's minimum essential medium supplemented with 10% fetal bovine serum. These cells proliferated for several generations, and then synthesized large amounts of proteoglycans, yielding a cartilage-like tissue in 16 days. Cultures from the permanent and growth plate cartilages showed similar time courses for increases in DNA synthesis and proteoglycan production that reached similar maximal levels. Thereafter, they initiated the syntheses of alkaline phosphatase and 1,25-dihydroxycholecalciferol receptor and induced matrix calcification without additional phosphate. The increases in alkaline phosphatase, 1,25-dihydroxycholecalciferol receptor, and calcium contents in cultures from the permanent cartilage were consistently delayed for 4-7 days relative to the growth plate-derived cells, but caught up by Day 28. The maximal levels of alkaline phosphatase and 1,25-dihydroxycholecalciferol receptor in the cultures from the permanent cartilage were 40- to 100-fold higher than that of the in vivo permanent cartilage. These results provide evidence that permanent cartilage cells in postnatal young rabbit ribs have the capacity to express alkaline phosphatase and 1,25-dihydroxycholecalciferol receptor and induce calcification in a permissive environment, although they never express these calcification-related phenotypes in vivo.

Alkaline Phosphatase↗
PubMed1989

Electrophysiological studies of intermittent claudication in lumbar stenosis.

To clarify the pathophysiology of intermittent claudication in 37 patients with lumbar spinal stenosis, neural function was evaluated by examining somatosensory evoked potentials (stress-SEPs), and nerve action potentials (stress-NAPs) before and after walking stress. It was shown preoperatively that the stress-SEPs became abnormal immediately after walking in 31 of 37 patients. In seven of nine operated patients, the assessment clearly shows that SEPs had reverted to normal after surgery. The present method is noninvasive, simple in technique, painless, and safe, a procedure therefore that is useful as the initial step in the diagnosis and treatment of patients with lumbar canal stenosis. It also may help to differentiate neurogenic from vascular intermittent claudication.

Adult↗
PubMed1989

Studies on new phosphate ester antifungal antibiotics phoslactomycins. I. Taxonomy, fermentation, purification and biological activities.

New antibiotics phoslactomycins A, B, C, D, E and F, which contain alpha, beta-unsaturated delta-lactone, phosphate ester, conjugated diene and cyclohexane ring moieties, were isolated from the culture broth of a soil isolate actinomycete. Morphological, cultural and physiological studies revealed that the isolate is a strain of Streptomyces nigrescens. Phoslactomycins were obtained by butanol extraction, gel filtration and reverse phase chromatography. The antibiotics show strong activity against various fungi, particularly phytopathogenic fungi (Botrytis cinerea and Alternaria kikuchiana).

Anti-Bacterial Agents↗
PubMed1989

[Three staged operation for aneurysms of abdominal thoracoabdominal and aortic arch].

Sixty-one year old man, who was diagnosed as abdominal and thoracoabdominal aortic aneurysms, underwent only Y graft replacement for abdominal aortic aneurysm. Two years later, the graft replacement was carried out for the thoracoabdominal aortic aneurysm. Three years after the second operation, graft replacement of the aortic arch was performed under separate cerebral perfusion technique as a supportive measure, because of the gradual growth of the arch aneurysm. We recommend the distal aneurysm (abdominal aortic aneurysm) should be removed first to prevent the detachment of the thrombus in the aneurysm during proximal operation.

Aorta, Abdominal↗
PubMed1989

Nuclear binding sites for reverse triiodothyronine in human placenta.

It has been generally believed that reverse triiodothyronine (reverse T3, rT3) is biologically inactive. Nevertheless the serum rT3 level is very high in fetal life, when the serum calcium level is higher than in the maternal. For this hypercalcemia in fetal life, there is no convincing evidence that any major calcium regulating hormone is responsible. And the assumption that rT3 may be concerned in active transport of calcium at placenta could be suggested. In this study nuclear protein was isolated from human placenta by extraction with 0.4M KCl buffer and binding studies utilizing radioactive rT3 were carried out. Scatchard analysis presented a curvilinear pattern, suggesting two classes of receptors: One with a association constant (Ka) of 1.14 X 10(8) M-1 and a limited capacity (Bmax) of 32.0 X 10(-15) mol/100 micrograms DNA and the other with Ka = 4.34 X 10(6) and Bmax = 454 X 10(-15). Its relative affinities for several thyroid hormone analogues were calculated. If the affinity for rT3 was assigned l, that for triiodothyronine would be 1/40, thyroxine: 1/63, Triiodothyroacetic acid: 1/18. Sulfhydryl agents affecting these binding characteristics were also studied. The Ka was not substantially changed but the Bmax was notably decreased by dithiothreitol (43%) and 2-mercaptoethanol (26%). In liver nuclei, the binding characteristics of rT3 receptor were analyzed for comparison. In this case only a single class of low affinity-high capacity rT3 binding site with a Ka of 6.69 X 10(6) was detected, a finding which was apparently different from those in placenta.(ABSTRACT TRUNCATED AT 250 WORDS)

Binding Sites↗
PubMed1989

[Evaluation of myocardial protection with DBcAMP in crystalloid cardioplegic solutions].

The potential for myocardial protection during cardiac operation was evaluated by adding Dibutyryl cyclic AMP (DBcAMP) to the crystalloid cardioplegic solutions. We have compared the cold crystalloid cardioplegia with DBcAMP (Group D n = 15) and without DBcAMP (Group n = 20) in patients undergoing cardiac operation. In hemodynamics, both groups were no difference before and after operation. CPK and CPK-MB was significantly (p < 0.01) high level after cardiopulmonary bypass (CPB) in group C. Myoglobin was also high value after CBP in group C, but not significant. Myocardial oxygen extraction rate and coronary blood PCO2 release were similar change in both groups. Insulin/glucose ratio was high level during and after CBP in group D. Myocardial lactate/pyruvate ratio was very high level after CBP in group C without significant difference. We consider that the cardioplegic solution with DBcAMP is effectual for the myocardial metabolism and preservation of myocardial damage during cardiac arrest.

Adult↗
PubMed1988

[Extra-anatomic bypass grafting for vascular occlusive disease in the upper and lower extremities].

Twenty-four patients with poor risk factors underwent an extra-anatomic bypass operation for aortoiliac occlusive disease and subclavian steal syndrome. A femoro-femoral bypass was performed on 5 patients, an axillo-femoral bypass on 15, a subclavian-subclavian bypass on 2 and an ascending aorta-femoral bypass on 2. There was only one operative death and there were 2 late deaths (8.3%). The patients were 20 males and 4 females with a mean age of 69.3 years. Among risk factors, high age (70 year old) was present in half of the patients, ischemic heart disease in 9, and cerebral vascular disease in 8. Seventy-five percent of the patients were suffering from two or more dysfunctions. During the limited follow-up period from 8 to 94 months (mean 46.1 months) there was a 96% patency rate. We had good results using externally supported ring graft and by the administration of prostaglandin E1 and ticlopidine during the pre and postoperative period.

Aged↗
PubMed1988

Studies on lymphocyte subsets in thymic tissue and functions of peripheral lymphocytes in patients with tumorous thymus with special reference to myasthenia gravis.

In order to obtain a better understanding of the immunological abnormalities present in myasthenia gravis (MG), which is often accompanied by thymoma or thymic hyperplasia, we investigated lymphocyte subsets and their functions using samples of thymoma or thymic hyperplasia tissues from 11 patients (6 cases with MG), and peripheral blood from 6 patients (4 cases with MG). In most thymic tissues from patients with MG, a maturating tendency of lymphocytes was generally observed. Especially in the medulla of thymic hyperplasia, an entirely peripheral blood type of T-lymphocytes, which were Leu-6- and either Leu-2a+ or 3a + 3b+, were encountered abundantly. Therefore, the presence of abnormal maturation of lymphocytes in the thymus or destruction of the barrier between the thymus and the peripheral blood in MG cases was indicated. In cases without MG, no such tendency was noted. As to the peripheral blood in patients with MG, concanavalin A-induced suppressor cells were significantly decreased (p less than 0.01). All of these changes were considered to be intimately related to the appearance of MG.

Adult↗
PubMed1987

Arugomycin, a new anthracycline antibiotic. I. Taxonomy, fermentation, isolation and physico-chemical properties.

Arugomycin (AGM) is a new anthracycline antibiotic produced by strain No. 1098-AV2 which was identified as Streptomyces violaceochromogenes. AGM was isolated by solvent extraction, silicic acid chromatography and Sephadex LH-20 column chromatography. Acid treatment of AGM gave the chromophore, named arugorol, which was identified as 4'-epi-nogalarol, and sugar moieties. AGM inhibited the growth of Gram-positive bacteria and showed antitumor activity against sarcoma S-180 and Ehrlich ascites tumors.

Animals↗