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Biomedical subjects

A Nakashima

Publications and source records attributed to A Nakashima.

At least 145 records · Page 8Linked to original sources
PubMed1984

Familial amyloidosis. A histopathological study.

Four autopsy cases of familial amyloidosis were reported. The ages of the patients ranged from 37 to 51 years consisting of 3 males and 1 female. They all complained of neurological symptoms. Histologically, amyloid deposition in familial amyloidosis was different in site and grade from that of other types of amyloidosis, showing heavy deposition in nervous and endocrine system but no differences were found referring to deposition in other tissues. Electronmicroscopically, the peripheral nervous tissue was examined and amyloid fibrils were found to be deposited massively in interstices of nerve fiber.

Adult↗
PubMed1983

Morphologic study on aorta dot stained with Evans blue in normal and hypercholesterolemic rabbits.

When a normal rabbit is injected intravenously with Evans blue, focal blue areas showing strong permeability appear in a region of the aortic arch and in a region distal to the orifice of the aortic branches. These blue areas consist of the dot stained area but are not homogeneous blue area. The morphological changes in the intima of the dot stained area and the relationship between the appearance of dot stained area and lipid deposition in the aorta of cholesterol fed rabbit were investigated. Evans blue showed focal acceleration of the permeability at the region of the aortic arch as early as 10 minutes. Light and electron microscopically such dot stained areas showed the widening of subendothelial space, lifting of some endothelial cells, intracytoplasmic vacuoles and membranous structure, junctional dilatation, and enhanced permeability of peroxidase. In 2% cholesterol fed rabbits, lipid deposition showed a punctuate pattern similar to the dot stained area of normal rabbit.

Animals↗
PubMed1983

[Case of disseminated necrotizing leukoencephalopathy following intrathecal methotrexate in acute lymphocytic leukemia].

Disseminated necrotizing leukoencephalopathy was found upon autopsy of a 32-year-old man with acute lymphocytic leukemia. He had been treated with intrathecal methotrexate for CNS involvement; no radiation therapy had been given. Autopsy findings revealed that in the white matter of the temporal lobe, there was widespread necrosis associated with numerous foam cells, demyelination, vacuolization and slight gliosis; in this lesion, leukemic cells infiltrated the Virchow-Robin space. In the white matter of other lesions we found discrete multifocal necroses of coagulative type associated with round or rod-shaped axonal swelling partly accompanied with calcification. However, in these lesions, there was no leukemic cell infiltration.

Adult↗
PubMed1982

Chronotropic effects of angiotensin I, angiotensin II, bradykinin and vasopressin in guinea pig atria.

Chronotropic responses to angiotensin I and angiotensin II, vasopressin and bradykinin were measured in guinea pig isolated right atria. Angiotensin II (100-30,000 pg/ml) was slightly more potent than angiotensin I and caused a maximum tachycardia of 30-40 b/min; only 20% of the maximum response to (--)-noradrenaline. Propranolol (1 micro M) or reserpine pretreatment (1 mg/kg i.p., 24 h) did not alter the response to angiotensin II or bradykinin. Converting enzyme inhibition by captopril (10 micrograms/ml) did not affect resting rate nor the response to angiotensin II but shifted the location of the angiotensin I curve by 40 fold to the right. Bradykinin (5-500 ng/ml) caused small increases in rate while vasopressin 1-100 ng/ml was completely without effect. These results suggest that angiotensin II has a small positive chronotropic effect that is not dependent on tissue noradrenaline release or beta-adrenoceptors and that tissue converting enzyme is active in right atria. Relatively high concentrations of angiotensin and bradykinin were required to directly stimulate the sino-atrial node compared with plasma levels measured during physiological stimuli. Therefore these effects on atria are probably of little physiological significance for peptide concentrations in plasma but may be important in relation to local tissue generation of angiotensin II.

Angiotensin I↗
PubMed1982

Comparison of angiotensin converting enzyme inhibitors captopril and MK421-diacid in guinea pig atria.

Angiotensin I (AI) and angiotensin II (AII) caused concentration-dependent increases in atrial rate in guinea pig isolated right atria. Converting enzyme inhibitors captopril and MK421-diacid did not alter the responses to AII but displaced the curves to AI to the right. The atrial response to generated AII from AI was used as a bioassay to estimate the dissociation constants of converting enzyme inhibitors (Kb) and test for kinetics of simple competition. MK421-diacid was 12-40 times more potent than captopril. However, estimations of Kb for captopril and MK421-diacid were unsatisfactory because at high concentrations of inhibitors the curves to AI were not displaced according to simple competition. We conclude that AI in high concentration can stimulate AII receptors accounting for the stationary displacement of curves to AI in the presence of converting enzyme inhibitors. MK421-diacid also potentiates responses to bradykinin in this assay.

Angiotensin I↗
PubMed1982

Asplenia and polysplenia syndrome.

This report described the morphological characteristics of seven cases of asplenia syndrome and three of polysplenia syndrome. Each syndrome has been characterized by a tendency for symmetric development of normally asymmetric organs, with varying degrees of cardiovascular anomalies. These latter anomalies are usually present in asplenia syndrome to a greater extent than in polysplenia syndrome. While, as observed in our material, the conotruncal anomalies were present more commonly in cases with asplenia, and absence of inferior vena cava with azygos continuation was seen specifically in all the cases with polysplenia. This evidence implied the presence of some pathogenetic distinction between the two syndromes.

Abnormalities, Multiple↗
PubMed1981

[Echocardiographic findings of pulsus paradoxus: cardiovascular changes due to respiration (author's transl)].

Echocardiographic studies were performed in two cases with pulsus paradoxus (Case 1: a 13-year-old boy, acute viral pericarditis with massive pericardial effusion; Case 2: a 25-year-old woman, status asthmaticus) and in a normal subject when his intra-airway pressure rapidly fell on a deep negative level, e.g., during Mueller maneuver. During inspiration in both clinical cases, the anterior mitral leaflet showed a diminished diastolic excursion, and the right ventricular dimension increased accompanied by a reciprocal decrease in the left ventricular dimension. In Case 2, in addition, an abrupt downward motion of the ventricular septum was present in early diastole during inspiration. In experimental study of a normal subject, similar respiratory changes in mitral ans septal motions and the similar respiratory interaction between the right and left ventricles were also observed during Mueller maneuver. Our observations suggest left ventricular filling and left ventricular end-diastolic volume decrease during inspiration in the presence of pulsus paradoxus. These are compatible with the pulmonary pooling hypothesis, and also support the hypothesis that pulsus paradoxus may be caused by competition of the ventricles for filling within a relatively fixed pericardial space. The mechanism of the abrupt downward septal motion in early diastole was also discussed.

Adolescent↗
PubMed1981

[The effect of the Valsalva and Müller maneuvers on right and left atrial dimensions in man studied by esophageal echocardiography (author's transl)].

The effect of the Valsalva (V) and Müller maneuvers (M) on the right and left atrial dimensions was evaluated by esophageal echocardiography in 8 normal male subjects. During V and M, the right atrial free wall (RAW), interatrial septum (IAS) and left atrial posterior wall were recorded by esophageal echocardiography simultaneously with intraairway pressure (Paw). Right (RAD) and left atrial dimensions (LAD) at atrial end-diastolic were measured at various phases during each maneuver. Mean expiratory effort of +40 mmHg Paw in V and mean inspiratory effort of -40 mmHg Paw in M were maintained for about 10 sec. Both atrial dimensions changed significantly during each maneuver. RAD began to decrease just after the onset of V, while LAD changed little during this phase, after which began to decrease progressively. The leftward displacement of IAS with the simultaneous outward displacement of RAW resulted in an increase of RAD and a decrease of LAD just after the onset of M and the release of V. LAD remained higher than resting value from the second (2--4 sec after the onset) to late phase (just before the release) during M. RAD decreased just after the release of M. Thus, esophageal echocardiography was useful to evaluate both atrial dimensions during V and M.

Adult↗