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Biomedical subjects

T Sakamoto

Publications and source records attributed to T Sakamoto.

At least 973 records · Page 54Linked to original sources
PubMed1987

Computed tomographic imaging of the brain in after hypoglycemia coma.

A case of severe hypoglycemic coma was studied by sequential Computed Tomographic Imaging (CT) of the brain. The CT 1) was normal in the early stage, 2) subsequently showed a low density area, which was enhanced by the contrast medium, in the cerebral cortex and the boundary zone between the major cerebral arteries, and 3) revealed marked enhancement in the entire cortical region and hypodensity in the periventricular region in the late stage. These CT findings, representing the course of neural cell damage by severe hypoglycemia, are discussed from the pathophysiological viewpoint.

Adult↗
PubMed1987

Complete evaluation of the cardiovascular lesions in 24 patients with Takayasu's aortitis using four-image, intravenous digital subtraction angiography.

We studied the entire distribution of cardiovascular lesions with the use of intravenous digital subtraction angiography (DSA) in 24 patients having Takayasu's aortitis. The aorta, its branches, pulmonary vessels, and left ventricle were assessed by neck (anteroposterior), abdominal (anteroposterior), and chest (right and left anterior oblique) images. DSA showed multiple arterial lesions (n = 24) including proximal renal artery stenoses (n = 4), pulmonary arterial stenoses (n = 4), inferior-superior mesenteric arterial anastomoses (n = 3), brachiocephalic arterial aneurysms (n = 2), aortic root aneurysm (n = 1), diffuse left ventricular hypokinesis (n = 1), subclavian steal phenomenon (n = 1), and right aortic arch (n = 1). The incidence of total occlusion was highest in the right subclavian artery (n = 12). Average percent luminal stenosis (mean +/- S.D.) over the aorta and its branches tended to be smaller in patients with prior corticosteroid therapy (17.3 +/- 14.6%) than in those without (22.0 +/- 9.8%), but the difference was not significant. DSA (four-series) was useful in assessing the whole disease spectrum and often revealed subclinical lesions in this disease.

Adolescent↗
PubMed1987

Application and limitations of differential hybridization in the isolation of T cell-specific cDNA clones.

We investigated the limitations and effectiveness of differential hybridization in the cloning of T cell-specific cDNA (complementary DNA) molecular clones. By using the technique with T cell and B cell cDNA probes, together with Northern blot analysis, we successfully isolated cDNA clones exclusively expressed in T cells from 1 X 10(4) plaque-forming units of a T cell hybridoma. These clones represent 0.068% of the mass of the cytoplasmic mRNA. Our result shows that differential hybridization is an effective procedure when used in combination with Northern blot analysis for screening of genes selectively expressed in T cells.

Animals↗
PubMed1987

Effect of lactacidosis on pyridine nucleotide stability during ischemia in mouse brain.

Brain levels of NADH and NAD+ were measured in three models of cerebral ischemia to determine whether degradation of the pyridine nucleotides is enhanced in models that generate high concentrations of lactic acid. Complete ischemia (decapitation), in which lactate increased to 14 mmol/kg, caused a gradual decrease in the NAD pool to 50% of control by 2 h. During focal ischemia (occlusion of the middle cerebral artery), the decrease in the NAD pool was less pronounced (82% of control at 2 h) despite the accentuated accumulation of lactate to 33 mmol/kg. In a third model (unilateral hypoxia-ischemia), pretreatment of animals with glucose augmented the ischemic elevation of lactate from 30 mmol/kg to 40 mmol/kg and greatly impaired restoration of energy metabolites during recirculation. However, glucose pretreatment had no effect on the size of the NAD pool during ischemia or early recovery. These results, therefore, demonstrate that the pyridine nucleotide pool is not rapidly degraded during ischemic insults that accumulate high concentrations of lactic acid. The stability of the NAD pool may have been enhanced by the limited increase in brain levels of NADH that occurred in these models of incomplete ischemia.

Acidosis↗
PubMed1987

[Maffucci's syndrome associated with primary brain tumor: report of a case].

A rare case of Maffucci's syndrome associated with astrocytoma at the right frontal lobe and intracranial chondroma is reported in detail with a review of literature. A 24-year-old male who had diagnosed as multiple chondroma at the age of 14 years old was admitted to the hospital with complaint of double vision. Neurological examination revealed no abnormality except for the left abducens palsy. Multiple subcutaneous blue nodules in the left hand was carried for biopsy as cavernous hemangioma. Craniograph showed expansive radiolucent area in the parasellar region. CT scan demonstrated a round shaped low density area in the right frontal lobe, part of which was iso-density and turned out to be enhanced following contrast infusion. Roentgenogram disclosed many well-demarcated radiolucent area in phalanges of the left hand and leg, and right leg and third rib. The frontal tumor was totally extirpated and was histologically fibrillary astrocytoma. This is the ninth case of the Maffucci's syndrome associated with the primary intracranial tumor in the literature. It is emphasized that the Maffucci's syndrome is associated with a high incidence of malignancy. And the reason for tendency to develop malignant tumors is discussed.

Adult↗
PubMed1987

[Left ventricular short-axis plane for magnetic resonance imaging: its clinical importance and applications].

Left ventricular short-axis images were obtained by ECG-gated magnetic resonance imaging (MRI) in nine patients with hypertrophic cardiomyopathy and seven patients with chest pain, all of whom had diagnostic cardiac catheterization including angiography. The accuracy and usefulness of the short-axis image in MRI for measuring wall thickness and dimension and for calculating ejection fraction were evaluated. All patients were examined on an examination couch in the right anterior oblique position in optimal positions to obtain the left ventricular long-axis images in the Z-X plane (conventional coronal plane). Next, the paraxial mode was used to obtain the short-axis images by rotating the Y-Z plane (conventional sagittal plane) around the Y axis. The intervals between the trigger on the middle point of the upstroke of the R wave and the 90 degree pulse of saturation recovery spin echo sequence were 40 msec and 340 msec with a 34 msec echo delay time for the end-diastolic and end-systolic images, respectively. Short-axis images in MRI in end-diastole were utilized to measure wall thickness and dimension in patients with hypertrophic cardiomyopathy and the measurements obtained were compared with those of echocardiography. As for calculating ejection fraction in patients with chest pain, the length of the left ventricular long axis (L) was measured using the MRI long-axis image. The intraventricular sectional area at four levels (S1, S2, S3, S4) were measured using the MRI short-axis image in end-diastole and in end-systole. Left ventricular end-diastolic and end-systolic volumes were calculated using the following formula: V = 1/2 X (L -4.5) X S1 + 1.5 X (S1 + S2 + S3) + 1/3 X 1/2 X (L -4.5) X S4. Ejection fraction by MRI was compared with that by cardiac catheterization (single plane, area-length method). The measurements of wall thickness and dimension by MRI correlated well with those by echocardiography (r = 0.97, p less than 0.01). Ejection fraction calculated by MRI correlated significantly with that by cardiac catheterization (r = 0.82, p less than 0.05). We concluded that the left ventricular short-axis image in MRI is satisfactorily accurate for measuring wall thickness and dimension, and useful for evaluating the left ventricular ejection fraction.

Angina Pectoris↗
PubMed1987

[Pulsed Doppler echocardiographic detection of regurgitant blood flow in the ascending, descending and abdominal aorta of patients with aortic regurgitation].

To ascertain whether the presence of retrograde holo-diastolic flow (RHF) in the ascending, descending or abdominal aorta is indicative of the severity of aortic regurgitation (AR), ascending, descending and abdominal aortic flow velocities were measured by pulsed Doppler echocardiography in 35 patients with AR and in 18 patients without AR, confirmed by aortography. Among the 35 patients with AR, 15 had mitral regurgitation, 11 had mitral stenosis, eight had aortic stenosis, five had prosthetic mitral valves, four had prosthetic aortic valves and two had aorto-pulmonary shunts. Satisfactory flow velocity recordings were obtained from the ascending aorta of 47 patients (89%), from the descending aorta of 39 patients (74%) and from the abdominal aorta of 43 patients (81%). In the ascending aorta, 30 of 32 AR patients with satisfactory recordings had RHF, while only one of the 15 patients without AR had RHF. None of the patients without AR had RHF, in either the descending or abdominal aorta. In the descending aorta, all 11 patients with 3+ or 4+ AR independently determined by aortography had RHF, while only three of 16 patients with 1+ or 2+ AR had RHF. Two of the three patients had aorto-pulmonary shunts. In the abdominal aorta, all 11 patients with 3+ or 4+ AR had RHF, while only one of the 22 patients with 1+ or 2+ AR had RHF. The latter patient had an aorto-pulmonary shunt. Identification of RHF in the descending or abdominal aorta is a useful means of distinguishing patients with severe AR from those with minimal or no AR.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1987

[Aortic regurgitation in hypertrophic cardiomyopathy as detected by color Doppler echocardiography].

Aortic regurgitation (AR) in patients with hypertrophic cardiomyopathy (HCM) has rarely been reported. Using color Doppler echocardiography, we assessed the incidence and the cause of AR in patients with HCM. There were 86 patients with HCM (M:F = 66: 20, 57 +/- 12 years, mean +/- SD) and 43 control subjects (M: F = 33: 10, 57 +/- 8 years). HCM was diagnosed by echocardiography; the thickness of the interventricular septum (IVS) was more than 15 mm and the ratio to the thickness of the left ventricular free wall (LVPW) was more than 1.3. The rate and degree of aortic regurgitation were observed by color Doppler echocardiography, and aortic regurgitant murmurs were recorded by phonocardiography. Echocardiographic measurements were made using standard techniques. In the M-mode echocardiograms, the aortic diameter, the thicknesses of the IVS and LVPW were measured. In the 2DE, calcification of the aortic valve and systolic anterior movement of the mitral valve (SAM) were evaluated. In the early systolic 2DE image, the distance from the point of the greatest bulging of the upper IVS to the aortic root (D1) and the distance from the point of the greatest bulging to the line which is parallel to the long axis of the aorta (D2) were measured. Results were as follows: 1. Color Doppler echocardiography revealed aortic regurgitation in 17 (21%) patients with HCM; whereas it was observed in only three (7%) of the control subjects. 2. The aortic regurgitant signals were limited to the left ventricular outflow tract both in patients with HCM and in the control subjects. 3. Aortic regurgitant murmurs were recorded in only two patients with HCM and in none of the control subjects. 4. There was no difference between the patients with and without AR as to age (59 vs 56 years), blood pressure (141/84 vs 136/80 mmHg), aortic diameter (34 vs 33 mm), aortic valve calcification (12% vs 9%) and SAM (53% vs 52%). 5. In the patients with HCM, D1 was shorter (9.9 vs 14 mm, p less than 0.001) and D2 was longer (16 vs 10 mm, p less than 0.001) in the patients with AR than in those without AR. That is, the basal septum of the patients with AR protruded more deeply into the outflow tract, and the distance to the aortic valve was significantly shorter than in those without AR.(ABSTRACT TRUNCATED AT 400 WORDS)

Aged↗