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Biomedical subjects

M Endo

Publications and source records attributed to M Endo.

At least 847 records · Page 47Linked to original sources
PubMed1987

Increase in Ca++ sensitivity of the contractile system by MCI-154, a novel cardiotonic agent, in chemically skinned fibers from the guinea pig papillary muscles.

The effects of MCI-154, a novel cardiotonic agent, on the contractile protein system and the sarcoplasmic reticulum (SR) were investigated by using thin bundles of chemically skinned fibers from the guinea pig papillary muscles. In the skinned muscle fibers treated with 50 micrograms/ml of saponin, MCI-154 shifted the -log[Ca++]M-tension relation curve to the left and upward in the concentration-dependent manner (10(-7) to 10(-4) M). This was confirmed also in the skinned muscle fibers treated with 250 micrograms/ml of saponin which destroyed not only the surface membrane but also the function of SR. Sulmazole (10(-4) M) shifted the -log[Ca++]M-tension relation curve to the left but the effect was about 100 times less potent than that of MCI-154. Unlike MCI-154, sulmazole had little effect on the maximum tension development induced by -log[Ca++]M 4.4. Milrinone did not affect the Ca++-induced tension development in the skinned cardiac fibers. Higher concentration of MCI-154 (10(-4) M) also increased amplitude of -log[Mg-ATP]M-tension-curve in the absence of free Ca++ ion (bell-shaped curve) to the upward. Initial rate and plateau phase of Ca++ uptake by the SR in the skinned fibers treated with 50 micrograms/ml of saponin was increased slightly by MCI-154 at the concentrations of 10(-6) and 10(-4) M. MCI-154 had no effect on the Ca++-induced Ca++ release mechanism in the SR. These results suggest that an increase in Ca++ sensitivity of the contractile protein system is responsible for, at least in part, the mechanism of the positive inotropic action of MCI-154.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗
PubMed1987

[Problems related to tracer concentration and wall thickness: pitfalls in positron CT diagnosis].

Positron emission computed tomography (PET) is regarded an excellent technique for quantitative measurements. However, its accuracy is related to the spatial resolution of the system. The relation between myocardial wall thicknesses as measured by X-ray CT or MRI and the radioactivity as measured using PET was studied in 37 patients. 1. In patients with transmural infarction, the infarcted myocardium was imaged as a region of low radioactivity. However, the myocardium usually exhibited wall thinning, so that partial volume effects must be taken into account in evaluating the radioactivity. 2. In the infarcted regions, the regions of the low radioactivity tended to be larger than those of wall thinning. 3. There were cases with the regional low radioactivity without wall thinning in myocardial infarction and in hypertrophic cardiomyopathy. Because patients with myocardial infarction frequently had regional wall thinning, it seems necessary to correct partial volume effects for the infarcted regions which differ from the normal. It was concluded that, to estimate regional myocardial blood flow or metabolism using PET, it is necessary to supplement another morphological diagnostic method to evaluate myocardial wall thickness.

Ammonia↗
PubMed1987

[Dynamic function studies with positron computed tomography: measurements of regional myocardial blood flow in hypertrophic cardiomyopathy].

A major attribute of positron computed tomography (PCT) is its ability to dynamically measure physiologic processes of the heart. However, quantitative data acquisition and analysis are limited by three major problems: bidirectional activity-cross contamination between the myocardium and the blood, the partial volume effect, and the lower temporal resolution of PCT devices. In the present study, we performed serial six-second PCT scans (fast dynamic study) using 13N-ammonia, and evaluated measurements of regional myocardial blood flow. Six patients with hypertrophic cardiomyopathy (HCM) and five normal subjects were observed. 13N ammonia (4.2-13.0 mCi) was intravenously injected as a bolus, and serial six-second PCT scans were initiated at the times of the tracer injections. The results were as follows: 1. Initial passage of the tracer through the right and left sides of the heart were observed with serial six-second images. 2. In patients with HCM, Myocardial 13N activity was determined by assigning a region of interest (ROI) over the myocardium of greater than 25 mm wall thickness as measured by contrast enhanced CT. In these ROIs, corrections for the partial volume effect and spillover of radioactivity from the blood were not necessary. Arterial 13N activity was determined noninvasively by assigning a ROI over the left atrium. 3. The temporal relationships between the arterial input function and myocardial tracer concentrations were demonstrated. Arterial 13N activity was greatest in the second or third frame, and it rapidly declined thereafter. Myocardial 13N activity increased rapidly, reaching a plateau from the sixth to the ninth frame.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Chemical characterization of urinary glycopeptides.

We prepared human urinary glycopeptides from the supernatant liquid remaining after precipitation of the nondialyzable fraction with cetylpyridinium chloride. Using cation exchange and affinity chromatographies and gel filtration, we obtained 28 glycopeptide subfractions. By compositional analyses of sugar and amino acid, and by reducing-terminal analyses after reduction with NaBH4, we determined the size of the carbohydrate moiety and the types of carbohydrate-peptide linkage involved. We isolated several glycopeptides not previously described: six with sialic acid, two with fucose, two with glucose, and one with N-acetylgalactosamine. The sialic acid glycopeptides had a short carbohydrate chain of the O-glycoside type. The fucose-containing glycopeptides were fucosyllactosaminoglycans. The glucose glycopeptides were polymers linked to a small peptide moiety. The N-acetylgalactosamine-rich glycopeptide was found in an N-glycoside-type fraction, with N-acetylgalactosamine at the nonreducing terminal.

Acetylglucosamine↗
PubMed1987

[A tentative subgrouping of the stage IV gastric cancer based on their postoperative prognosis].

Out of 211 patients with the Stage IV gastric cancer who survived gastrectomy, 105 died within one year (short-lived group) and 40 survived more than two years (long-lived group). The grades of the four factors, P, H, N and S, were compared between them. Combination of P0 and H0 was seen less often in the former group than in the latter (48% vs. 78%, p less than 0.005). While no patient with P3, H2-3 or N4 could live more than two years. The year-by-year survival rates were calculated according to the grades of the four factors. The 1-year, 2-year, 3-year and 4-year survival rates for the patients with both P0 and H0 were significantly higher than those of the remaining patients. The 1-year and 2-year survival rates for the patients with N0-3 significantly exceeded those of N4 patients. Based on these findings, we finally proposed a new subgrouping of Stage IV:IVa [P0, H0, N3, S3] and IVb [P1-3, H1-3, N4]. At every year up to five, the survival rates for IVa significantly exceeded those of IVb. Another merit of this classification consists in that most cancer in IVa might be radically resected if we add the lymph nodes dissection of R3 and the combined resection of the invaded organs.

Adult↗
PubMed1987

[Sleep spindles and physical parameters].

In 4 identical (Nos. 1-4) and 3 fraternal (Nos. 5-7) male twin pairs (mean age, 16 years), sleep spindles were analysed during sleep. The height, body weight, plantar length and chest circumference were measured, and the correlations between sleep spindles and these physical parameters were examined. The physical parameters showed concordance between identical twin pairs except one pair (No. 4) and one fraternal pair (No. 5) but discordance between two fraternal twin pairs (Nos. 6 and 7). Number of sleep spindles and sleep spindle density showed almost concordance between identical twin pairs and one fraternal pair (No. 5), while discordance between two fraternal ones (Nos. 6 and 7). Both number of sleep spindles and sleep spindle density were inversely correlated with body weight (r = -0.61, p less than 0.02; r = -0.62, p less than 0.02). These facts would suggest that sleep spindles rather reflect the individual development than genetic trait.

Adolescent↗