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Biomedical subjects

N Tamura

Publications and source records attributed to N Tamura.

At least 253 records · Page 14Linked to original sources
PubMed1990

[Autonomic nervous functions in Alzheimer type and multi-infarct dementia--a hemodynamic study].

As it has been recently postulated that patients with dementia have some altered neural transmission, these patients are speculated to accompany autonomic dysfunctions. The present study was aimed at investigating autonomic nervous functions in dementia of Alzheimer type (DAT) and multi-infarct dementia (MID). Hemodynamic autonomic functional tests were carried out on 14 patients with DAT (66.9 +/- 11.4 YO; mean +/- SD) and 9 patients with MID (73.1 +/- 7.5) and 16 age-matched healthy volunteers as controls. Blood pressure, pulse rate and respiration were continuously measured. The degree of reflex bradycardia in Aschner's test, a parameter for parasympathetic functions, was significantly lower in MID than in DAT and in the healthy volunteers (p less than 0.01, p less than 0.05, respectively), but there was no significant difference between DAT and the healthy volunteers in this reaction. The degree of reflex hypertension in cold pressor test, a parameter for sympathetic functions, was not significantly different among 3 groups. The degree of orthostatic hypotension also failed to show any significant difference among the groups. From the above data, it is suggested that the patients with DAT have preserved autonomic nervous functions, but that the patients with MID have impaired parasympathetic and normal sympathetic nervous functions.

Aged↗
PubMed1990

[Surgical treatment of aortic arch aneurysm associated with the aberrant right subclavian artery].

A 64-year-old man, who had an aneurysm of aortic arch associated with the aberrant right subclavian artery, was treated successfully. He was pointed out to have an aneurysm of aortic arch three years ago. Three years later angiograms and computed tomography revealed that it became larger compared with the initial finding. He underwent a replacement of the aortic arch using a woven Dacron graft under open distal method. Aberrant subclavian artery was not involved in the aneurysm. But because the left subclavian artery was involved in it, a woven Dacron graft was interposed between the ascending aorta and left subclavian artery. Postoperative course was uneventful and there were no complications.

Aorta, Thoracic↗
PubMed1990

[A new quantitative test for parasympathetic nervous function by means of tear volume measurement--application of electronic resistance measuring device (Periotron)].

Because reflex secretion of tears is under the sole control of parasympathetic nervous system, tear volume measurement may be useful as a quantitative test for the parasympathetic nervous function. Recently, an electronic resistance measuring device (Peritron: Harco Electronics) has been applied to determine tear volumes. The present study was designed to known whether, or not, the tear volume measured by this device could be an index for the parasympathetic nervous function. By means of Periotron, tear volumes were determined before and after intravenous administration of atropine (500 micrograms) in six control subjects without autonomic and ophthalmologic disorders. Tear volumes were also measured in five patients with acute or subacute hemispheric cerebrovascular disease, in which the parasympathetic nervous function was known to be decreased. In the control subjects, reflex tear volume was 58.6 +/- 13.8 (mean +/- SD) units before the administration of atropine, and it was significantly reduced to 34.1 +/- 9.9 units by atropine (p less than 0.001). In the stroke patients, it was 48.8 +/- 16.5 units in the healthy side and 33.0 +/- 6.7 units in the hemiplegic side, and the value was significantly lower in the hemiplegic side than in the healthy side and in the controls (p less than 0.05, p less than 0.002, respectively). It was concluded that tear volume measurement by means of Periotron was applicable to quantitative assessment of the parasympathetic nervous function.

Aged↗
PubMed1989

Effect of decay-accelerating factor on the assembly of the classical and alternative pathway C3 convertases in the presence of C4 or C3 nephritic factor.

Decay-accelerating factor (DAF) is a 70,000 MW membrane protein that regulates the complement system on the cell surface. In the present study, we found that DAF had no effect on the classical pathway C3 and C5 convertases that had been stabilized by C4 nephritic factor (C4NeF). In DAF-incorporated cells, however, the assembly of the classical pathway C3 convertase was markedly inhibited even in the presence of C4NeF. C3 nephritic factor (C3NeF) in the alternative pathway protected the C3 convertase from the action of DAF to some extent, while the generation of C3 convertase was also inhibited by DAF. These results indicate that under physiological conditions, DAF functions to inhibit the assembly of C3 convertases even in the presence of nephritic factors, although it has no or little effect on the stabilized convertases. Thus, it is likely that DAF plays an important role in protection of host cells from damage by autologous complement in patients with nephritic factors.

Autoantibodies↗
PubMed1989

[Aortic aneurysm associated with coarctation of the aorta].

An 8-year-old female of coarctation of the aorta associated with thoracic aortic aneurysm is reported. Under cardiopulmonary bypass, a 7 cm section of the aorta containing the aneurysm and coarctation was resected and replaced by a 16 mm woven Dacron tube. The postoperative recovery was complicated by chylothorax treated by thoracic aspiration. She is doing well 3 months after the operation. Histologic sections of the resected portions of the thoracic aorta revealed intimal hyperplasia, medial fibrosis and decrease of elastic fibers, especially in the aneurysm.

Aorta, Thoracic↗
PubMed1989

[Primary orthostatic hypotension syndromes without somatic neurologic signs--idiopathic orthostatic hypotension and primary sympathicotonic orthostatic hypotension].

Idiopathic orthostatic hypotension (IOH) and primary sympathicotonic orthostatic hypotension (PSOH) are conspicuous orthostatic hypotension syndromes without overt somatic neurologic signs. IOH, also referred as pure autonomic failure, is a syndrome of chronic pandysautonomia, and its clinical features include supine hypertension, anhidrosis, impotence, neurogenic urinary and bowel disturbances. PSOH is different from IOH in which it is not accompanied with autonomic features outside of cardiovascular symptoms, and has been most commonly described in German-Scandinavian literatures. The controversy in the nosology of IOH and PSOH has prevented the both concepts from world-wide acceptance, and little has been known about IOH in Japanese population. In the present study, statistical analyses were made to elicit the cases of orthostatic hypotension syndrome without somatic neurologic signs from the pooled results of hemodynamic autonomic functional tests in our laboratory. The subjects were 287 Japanese cases comprising 253 normotensive volunteers and 34 hypertensive patients. Apart from hypertension, none of the subjects exhibited abnormal findings on physical, neurological and routine laboratory examinations. The test of 70 degrees passive head-up tilt and other hemodynamic tests were performed upon the subjects, and the results were pooled by ages. By means of the method of maximum normed residual, statistically screened out were 7 cases with extremely great orthostatic fall in systolic blood pressure (OH-I). Another OH group (OH-II) consisted of 24 cases who showed orthostatic decrease in systolic blood pressure of 30 mmHg or more, but did no fall into the extreme observation. Assuming that the orthostatic regulation mechanism of blood pressure was well maintained in the remaining 256 cases, they were used as the control.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Leukotriene C4 production from human eosinophils in vitro. Role of eosinophil chemotactic factors on eosinophil activation.

We studied the role of naturally occurring eosinophil chemotactic factors on leukotriene (LT)C4 production from highly purified (87.1 +/- 2.4%) normodense eosinophils. Platelet activating factor (PAF) directly induced LTC4 production from eosinophils in a dose (10(-9) to 10(-5) M) and a time-dependent manner. PAF (10(-5) M) induced 0.74 +/- 0.08 ng of LTC4 production/10(6) eosinophils. However, lyso-PAF, eosinophil chemotactic factor of anaphylaxis, and LTB4 failed to induce LTC4 production within the tested range. Furthermore, the pre-incubation of eosinophils with 5 micrograms/ml of cytochalasin B did not alter the chemotactic factor-induced LTC4 production. When eosinophils were stimulated by the submaximal concentration (1 microgram/ml) of calcium ionophore A23187, the pre-incubation of eosinophils with 10(-6) M or 10(-5) M of PAF, or 10(-5) M of eosinophil chemotactic factor of anaphylaxis significantly enhanced LTC4 production up to 163.9 +/- 17.5% (p less than 0.05), 279.2 +/- 32.9% (p less than 0.01) and 165.2 +/- 21.2% (p less than 0.05) of the control, respectively. However, the pre-incubation with lyso-PAF or LTB4 failed to enhance A23187-induced LTC4 production. The pre-incubation of eosinophils with phosphatidyl serine also failed to enhance A23187-induced LTC4 production. However, the direct stimulation of protein kinase C by PMA enhanced the submaximal concentration of A23187-induced LTC4 production from eosinophils up to 179.5 +/- 20.9% (p less than 0.05) of the control. Our findings indicate that PAF and ECF-A work not only as chemotactic factors but also induce a functionally active state of eosinophils probably through their post-receptor mechanisms, and contribute to the inflammatory processes.

Adult↗
PubMed1988

A morphometric study of the carotid sinus nerve in patients with diabetes mellitus and chronic alcoholism.

Morphometric studies were performed on the myelinated fibres of the carotid sinus nerve obtained at autopsy from 13 control subjects, 7 patients with diabetes mellitus and 11 with chronic alcoholism. The myelinated fibre-diameter distribution in control nerves was bimodal with peaks at 3-4 micron and at 8-10 micron. The mean myelinated fibre density was 14.8 X 10(3)/mm2 (SD 2.3 X 10(3)/mm2) in control nerves and was significantly reduced in the nerves of diabetics (mean, 11.7 X 10(3)/mm2; SD, 2.2 X 10(3)/mm2), and chronic alcoholics (mean, 12.7 X 10(3)/mm2; SD, 2.1 X 10(3)/mm2), although in 8 of 11 nerves from alcoholics, the density was within the control range. These findings demonstrate that autonomic afferent fibres are damaged in diabetes and chronic alcoholism, and provide a pathological basis for the disturbances of heart rate and blood pressure control in these conditions.

Adult↗
PubMed1988

Purification and characterization of decay-accelerating factor (DAF) from Raji cells.

Decay-accelerating factor (DAF), a membrane protein that regulates the complement system, was purified to homogeneity from lymphoblastoid (Raji) cells (DAF-R). It exhibited almost the same molecular weight as DAF from stroma of erythrocytes (DAF-S). Purified DAF-R, which could be reincorporated into cell membranes, accelerated the decay of the C3 convertases, in both the classical (C4b2a) and the alternative (C3bBb) pathways. This activity was completely inhibited by a monoclonal anti-DAF antibody, 1C6. From these results, DAF-R and DAF-S can not be distinguished; however, the decay-accelerating activity of DAF-R was much higher than that of DAF-S. 1C6 enhanced the binding of C3 to Raji cells by incubating with six purified components of the alternative pathway, whereas it did not induce the killing of Raji cells after a short incubation period. When antibodies against Raji cells were added to the above system, the blocking of DAF activity by 1C6 resulted in efficient killing of Raji cells by autologous complement. From these results, it is clear that DAF on nucleated cells plays an important role in protecting these cells from the damage caused by autologous complement.

Burkitt Lymphoma↗