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Biomedical subjects

M Takamiya

Publications and source records attributed to M Takamiya.

At least 127 records · Page 7Linked to original sources
PubMed1990

[Progression to the dilated phase of hypertrophic cardiomyopathy in children].

Twenty-three children with hypertrophic cardiomyopathy (HCM) (aged 2 months to 15 years) were followed up for more than four years using thallium myocardial imaging (TMI) and echocardiography. With echocardiography, the left ventricular end-diastolic dimension (LVDd) and fractional shortening (FS) were measured. Perfusion defect (PD) was assessed using TMI. Cardiac catheterization and right ventricular endomyocardial biopsy were performed in 18 patients within one week before or after their TMI. During the follow-up period, two patients showed a marked increase in LVDd and a marked decrease in FS at ages 13 and 16 years, respectively. These two patients were judged to have progressed to the dilated phase. In these two patients, extensive PD was detected in the left ventricular wall on TMI, 15 and 31 months prior to the appearance of the echocardiographic changes, respectively. Right ventricular endomyocardial biopsy at the time of extensive PD revealed marked interstitial fibrosis along with hypertrophy and disarray of myocardial cells. In conclusion, progression to the dilated phase is not a rare event in children with HCM and TMI appears to be a useful tool for early detection of the progression.

Adolescent↗
PubMed1990

[Percutaneous transluminal angioplasty of the subclavian artery].

We reported a case of subclavian artery stenosis successfully treated by percutaneous transluminal angioplasty (PTA). He suffered from left arm claudication and proximal subclavian artery stenosis. The stenosis and symptoms disappeared soon after PTA. No complications occurred. Patients with hemodynamically significant stenoses, symptoms and signs should be considered for PTA.

Angioplasty, Balloon↗
PubMed1990

[Ultrafast CT scanner; preliminary experience in Japan].

We evaluated the usefulness of Ultrafast CT scanner C-100 (UFCT) in 30 patients' clinical practice. UFCT was very useful not only for cardiac studies but for other body organs' studies. Simultaneous multilevel ultrafast scans of UFCT enabled us to analyse cardiac ventricular motion not only by the ejection fraction but by the change of wall thickness. We could get ultra-early contrast phase images (within one minute images from contrast medium injection start) of contiguous 15, 1 cm interval levels by high quality single slice mode of UFCT. These ultra-early phase images and late phase images would be helpful for tissue characterization.

Adolescent↗
PubMed1990

[Evaluation of aortic dissection by ultrafast computed tomography].

We report usefulness of ultrafast CT (UFCT) in evaluation of aortic dissection, according to the results of examination of 51 patients. By volume mode study of UFCT, aortic dissection was diagnosed in all patients. Fine structures such as intimal tear and ulcer-like projection were depicted in detail. Pulsatile movement of true and false channels was detected by cine study. Precise flow analysis of both channels was available by flow mode study of UFCT. In morphological and functional assessment of aortic dissection, UFCT is superior to conventional scanners, and may be preferable to DSA or MRI.

Aortic Dissection↗
PubMed1990

[Clear visualization of the tracheobronchial tree in complex congenital heart disease using digital subtraction fluorography].

We knew that digital subtraction fluorography (DSF) could clearly visualize the tracheobronchial tree by the respiratory movement. We applied DSF for 54 patients of complex congenital heart disease. In the visualization of the tracheobronchial tree, DSF was significantly superior as compared with the plain chest radiography (p less than 0.01). As this method needs to anesthetize patients to suppress their body movements, there might be some limitation to apply it for routine diagnostic workup. However, noninvasiveness and readiness of diagnosis justifies this method as an optional examination for confirming thoracic situs of complex congenital heart disease.

Bronchography↗
PubMed1989

Characterization of the two rRNA gene operons present in Thiobacillus ferrooxidans.

The organization of rRNA genes from the autotrophic, acidophilic bacterium Thiobacillus ferrooxidans has been examined. Two rRNA operons were found in this microorganism by means of genomic hybridization studies. Recombinant plasmids, pTR-3 and pTR-1 that carry a portion of 16/23 S rDNA from one operon and the 5'-flanking region of the second operon, respectively, were identified and characterized.

Cloning, Molecular↗
PubMed1989

Cerebral vascular malformations: applications of magnetic resonance imaging to differential diagnosis.

Twelve patients with cerebral vascular malformations (5 cavernous angiomas, 1 thrombosed arteriovenous malformation, and 6 venous angiomas) were studied with magnetic resonance (MR) imaging. All lesions were clearly depicted. Characteristic MR findings were obtained mainly on T2-weighted images: a markedly low intensity area was always seen. The margins of arteriovenous malformation (AVM) and venous angioma were irregular while those of cavernous angioma were smooth in all planes on T2-weighted images. Gradient-echo (GrE) pulse sequences were more sensitive than T2-weighted spin echo (SE) in lesion detection. MR imaging could play an important role in the differential diagnosis of cerebral vascular malformations.

Adult↗
PubMed1989

Rapid reduction of plasma atrial natriuretic peptide levels during percutaneous transvenous mitral commissurotomy in patients with mitral stenosis.

To clarify the direct contribution of the left atrial pressure to secretion of human atrial natriuretic peptide (hANP), we have attempted to study the relations between plasma hANP levels, neurohumoral factors, and hemodynamic changes in 13 patients with mitral stenosis undergoing percutaneous transvenous mitral commissurotomy (PTMC). After PTMC, the left atrial pressure fell from 14.7 +/- 1.9 (mean +/- SEM) to 6.5 +/- 0.7 mm Hg in all patients studied (p less than 0.0005), whereas there were no remarkable changes in either the right atrial pressure, mean arterial pressure, or heart rate. Plasma immunoreactive hANP levels obtained from the pulmonary artery decreased from 278 +/- 51 to 137 +/- 31 pg/ml after PTMC (p less than 0.0005). There was a significant correlation between the decrement of hANP levels and that of left atrial pressure (r = 0.72, p less than 0.005). Neither plasma renin activity nor norepinephrine levels changed. In contrast, plasma aldosterone concentrations significantly increased from 11.3 +/- 1.5 to 16.4 +/- 2.7 pg/ml after PTMC (p less than 0.01), although there was no casual relation between plasma concentrations of aldosterone and hANP. The present result with PTMC-induced rapid fall of the left atrial pressure with a concomitant reduction in hANP secretion strongly suggests the importance of the left atrial pressure on hANP secretion in humans.

Adult↗
PubMed1989

Aspirin lowers blood pressure in patients with renovascular hypertension.

To clarify the role of renal prostanoid in hyperreninemia and high blood pressure in human renovascular hypertension, we measured prostaglandin E2 and renin activity in renal venous and abdominal aortic plasma before and after the intravenous administration of the cyclooxygenase inhibitor, aspirin DL-lysine. Subjects were six patients with unilateral renovascular hypertension and six with essential hypertension. In patients with renovascular hypertension, prostaglandin E2 concentration in renal venous plasma from the stenotic kidney was 9.25 +/- 1.48 pg/ml, which was significantly higher (p less than 0.01) than the concentration in the renal venous plasma from the normal kidney (4.97 +/- 1.02 pg/ml) or in the aortic plasma (2.59 +/- 0.15 pg/ml). Plasma renin activity was also higher in the renal vein of the stenotic kidney than in the other two sites. The stenotic side/normal side ratio of the renal venous prostaglandin E2 correlated significantly with a renin ratio greater than 1.5 (r = 0.8211, p less than 0.05). Intravenous injection of aspirin DL-lysine (18 mg/kg) 30 minutes later markedly suppressed prostaglandin E2 and renin levels at all sites and clearly lowered arterial blood pressure (mean: from 120 +/- 6 to 110 +/- 5 mm Hg, p less than 0.01). The reduction in blood pressure correlated significantly with the suppression of plasma renin activity in the aorta (p less than 0.05) and in the renal vein of the stenotic kidney (p less than 0.01). Conversely, in patients with essential hypertension, aspirin had little effect on renin levels and increased mean blood pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Serial assessment of myocardial infarction by using gated MR imaging and Gd-DTPA.

In order to assess the usefulness of Gd-DTPA in the evaluation of myocardial infarction, 17 patients were examined with gated MR imaging. Scans were made by using a spin-echo pulse sequence before and after IV administration of 0.15 mmol/kg of Gd-DTPA. The images were made at four intervals (average of 5, 12, 30, and 90 days) after the onset of the infarction. Gd-DTPA uptake at the infarcted area was graded as marked, moderate, or no increase in signal intensity by visual inspection. At these four time intervals, an area of increased signal intensity in the infarcted myocardium was detected on T1-weighted images after administration of Gd-DTPA in 14 (82%) of 17 cases, 16 (94%) of 17 cases, six (38%) of 16 cases, and three (21%) of 14 cases, respectively. Markedly increased signal intensity in infarcted areas was shown on T1-weighted images with Gd-DTPA at 5 and 12 days. The ratio of gadolinium uptake in the infarcted area to that in normal myocardium also was evaluated. At 5 and 12 days, the mean increase in signal intensity in the infarcted area was significantly higher than that in a normal area, but not at 30 and 90 days. Increased signal intensity also was apparent on T2-weighted images without Gd-DTPA at 5 and 12 days; however, the use of late echo reduced the signal-to-noise ratio, leading to image degradation. Uptake of Gd-DTPA was a positive marker in acute myocardial infarction, but no significant uptake of Gd-DTPA occurred in chronic myocardial infarction.

Contrast Media↗
PubMed1989

[Magnetic resonance imaging of cerebrovascular disorders; cerebral infarction].

Patients with cerebral infarction and with suspicion of cerebral infarction were studied with magnetic resonance imaging (MRI) and correlative CT scans. MRI was more sensitive than CT for detecting cerebral infarction, and T2-weighted spin echo pulse sequence was most sensitive in the diagnosis of cerebral infarction except some lacunar infarctions and some cortical and subcortical infarctions. MRI using Gd-DTPA was more sensitive than contrast CT for detecting fresh infarcted areas, especially in the cases with multiple cerebral infarcted areas and cortical and subcortical infarcted areas, and many offer some informations in evaluating the state of circulation.

Adult↗
PubMed1989

[Gallium-67 imaging in patients with myocarditis in childhood and youth].

Gallium-67 (Ga-67) myocardial imaging was performed in 19 patients (1 month to 21 years of age) with proven or suspected myocarditis. The anterior images, 48 hrs after the intravenous administration of 0.5-2.0 mCi Ga-67 citrate, were analysed using a computer. Regions of interest were set on the heart, lungs and background, excluding the sternum and vertebrae. The uptake of Ga-67 was evaluated quantitatively by the ratio of the average count of the heart to the average count of the lung (H/L). When the H/L value was higher than 130% the cardiac uptake of Ga-67 was designated positive. Histological examination was performed in 11 patients who underwent right endomyocardial biopsy. The patients were categorized according to their clinical findings. Group 1 consisted of 11 patients with clinical symptoms of dilated cardiomyopathy, six of whom had arrhythmias or elevated serum CPK-MB levels (group Ia) in the acute stage of the disease, and the remaining five had neither (group Ib). Group 2 consisted of eight patients with dysrhythmias but without heart failure. Four had elevated serum CPK-MB levels (group IIa), but the remaining four did not (group IIb). All patients in the group Ia had positive Ga-67 uptakes, and three patients in the group Ib had negative uptakes. The H/L values were significantly higher in the group Ia than in the group Ib (p less than 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1988

Inhibition of mitogen-stimulated T lymphocyte proliferation by calcitonin gene-related peptide.

The effect of calcitonin gene-related peptide (CGRP) on mouse lymphocyte proliferation stimulated by mitogens was studied. CGRP (10(-10)-10(-7) M) dose-dependently inhibited the proliferative response of mouse lymph node cells and spleen cells stimulated by T cell mitogens concanavalin A (Con A) and phytohemagglutinin (PHA), whereas a B cell mitogen lipopolysaccharide (LPS) did not inhibit this response. The maximal inhibition by this peptide was 50% to 80% at 10(-8) and 10(-7) M. The addition of 10(-8) and 10(-7) M CGRP to lymph node cell cultures 24 hr after stimulation with Con A or PHA also had a significant inhibitory effect on the proliferative response. Furthermore, in the same concentration range (10(-10)-10(-7) M) CGRP increased intracellular cyclic AMP concentration in nylon wool nonadherent cells, but not in nylon wool adherent cells. CGRP had no significant effect on intracellular cyclic GMP concentration. In addition, specific binding of CGRP was observed in mouse spleen cells. Our present study suggests that CGRP inhibits the proliferative response of T lymphocytes to the mitogens by interacting with cell receptors coupled with adenylate cyclase. CGRP may be implicated in the regulation of T cell function.

Animals↗
PubMed1988

Magnetic resonance imaging of cerebral infarction: time course of Gd-DTPA enhancement and CT comparison.

Thirty-five patients (7 females and 28 males) with cerebral infarction and suspicion of cerebral infarction of 4 h to 27 months duration were studied 45 times with magnetic resonance (MR) imaging using Gd-DTPA. Spin echo (SE) images were obtained before and after the administration of Gd-DTPA (0.1 or 0.15 mmol/kg) and compared with the enhanced CT. MR imaging using Gd-DTPA was more sensitive than enhanced CT and very useful for detecting a new focus of cerebral infarction, especially in the cases with multiple infarcted areas and for showing the extent of cortical and subcortical infarction. In most cases the MR enhancement was obvious in the subacute stage, especially after cerebral embolism, and the signal intensity of the lesion tended to show a gradual increase. The diagnosis of embolism was accepted on the basis of acute onset without prior TIA, coupled with angiography showing the embolus itself and/or a capillary blush and a wide area of infarction.

Adult↗
PubMed1988

Toxins in the skin secretion of the oriental catfish (Plotosus lineatus): immunological properties and immunocytochemical identification of producing cells.

Antiserum against toxin I, one of the lethal factors in the skin secretion from the oriental catfish (Plotosus lineatus), was used to examine immunological properties of the toxic factors and identify toxin-producing cells by an immunocytochemical technique. In immunodiffusion tests, the antiserum formed a precipitin line with toxin I while it formed no precipitin line either with another lethal factor (toxin II) or with a hemolysin. Lethal and edema-forming activities of toxin I were neutralized by the antiserum but lethal activity of toxin II and lytic activity of the hemolysin were not. These results suggested that toxin I can be antigenically distinguished from both toxin II and hemolysin. In immunocytochemical tests using the antiserum, club cells in the epidermis were positively stained, indicating that toxin I is produced in the club cells. Interestingly, venom glandular cells surrounding the dorsal and pectoral spines were also stained. The venom glandular cells appear to produce toxin I or a toxin with the same antigen determinants as toxin I.

Animals↗
PubMed1988

Comparison of ionic and nonionic low-osmolar contrast media in coronary arteriography. A crossover study in children.

Twenty-six patients with Kawasaki disease were observed in a prospective crossover study to compare coronary arteriography with a nonionic low-osmolar contrast medium, iopamidol 370 mgI/mL, and with an ionic low-osmolar contrast medium, ioxaglate 320 mgI/mL. A slight heart rate change and no severe arrhythmia during coronary arteriography were observed with both agents. Electrocardiographically, QTc elongation and ST-T changes were marked in ioxaglate and minimal in iopamidol. No ventricular fibrillation occurred with either agent. Both contrast media provided adequate visualization for the diagnosis of Kawasaki disease, but the contrast of the images and the visualization of details were better with iopamidol than with ioxaglate. Iopamidol seems to be superior to ioxaglate in pediatric coronary arteriography.

Angiography↗