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Biomedical subjects

M Endo

Publications and source records attributed to M Endo.

At least 1,009 records · Page 56Linked to original sources
PubMed1982

[Insulin resistance with acanthosis nigricans: a case report].

We described a 12 7/12-year-old boy presenting the syndrome of insulin resistance and acanthosis nigricans Type A. Insulin levels at fasting state and after glucose loading were 149 +/- 63 microunits/ml (mean +/- SD) and over 1000 microunits/ml, respectively, while fasting levels of blood glucose were 77.7 +/- 8.9 mg/dl (mean +/- SD). A marked resistance to exogenous insulin was observed. Circulating levels of insulin antagonists such as growth hormone, cortisol and glucagon, were within the normal range. Proinsulin was less than 5% of the total radioimmunoassayable insulin. Insulin antibody and anti-receptor antibody were not detected. Insulin binding to mononuclear cells were decreased to about 50% of controls. Analysis of membrane receptors demonstrated the normal average affinity, dissociation kinetics and negative cooperativity with a decreased number of receptors. After two days fasting, plasma IRI levels decreased to 27 microunits/ml, however insulin binding kinetics were not affected. This might suggesting that the receptor decrease was not secondary to hyperinsulinemia. These findings indicate that a decreased number of receptors was one of the causes for insulin resistance in the patient.

Acanthosis Nigricans↗
PubMed1982

Histological and enzyme histochemical studies on the nephrons of the freshwater fishes, Cyprinus carpio and Carassius auratus.

The nephrons of carp (Cyprinus carpio) and goldfish (Carassius auratus) were examined histologically and also histochemically for enzymes. In both species the distal and collecting tubules have much wider lumens than do the other renal tubules; thus urine probably flows more slowly in these larger tubules. Enzyme histochemistry shows that epithelium of the neck and proximal and intermediate tubules respires anaerobically, whereas that of the distal and collecting tubules respires aerobically. The distribution of Na-K-ATPase in the distal and collecting tubules indicates that they also transport sodium actively. The slow flow of urine and the energy produced by aerobic metabolism probably increase the efficiency of active transport.

Animals↗
PubMed1982

Effect of correction function on image characteristics of Positologica: a positron CT device for the head.

The effects of correction function on image characteristics were studied experimentally for a positron CT device Positologica. Correction functions were obtained by smoothing the Shepp and Logan function by convolution of Gaussian functions. Signal-to-noise ratio (SNR) and spatial resolution were measured for phantoms and related to the magnitude of smoothing. The relation between SNR and spatial resolution is also discussed. Some suggestions are made to indicate how to select correction functions for clinical images. A flow of data processing for Positologica is described together with an outline of its hardware.

Computers↗
PubMed1982

Prolactin response to thyrotropin-releasing hormone in children with Turner's syndrome and hyperthyroidism.

Plasma prolactin (PRL) response to synthetic thyrotropin-releasing hormone (TRH) was studied in 26 prepubertal and 19 pubertal children with constitutional short stature, 7 patients with Turner's syndrome and 10 patients with hyperthyroidism. The mean basal concentrations of plasma PRL did not differ among groups. In prepubertal children PRL responses to TRH were comparable in both sexes, while pubertal children plasma PRL levels after TRH in females were significantly higher (P less than 0.05) than those in age-matched males. Plasma PRL levels after TRH in patients with Turner's syndrome were significantly higher (P less than 0.05) than those in age-matched males, but were not significantly different from those in age-matched females. Plasma PRL response to TRH was markedly suppressed in patients with hyperthyroidism before treatment, but it returned to normal after treatment when patients became euthyroid. A significant correlation (P less than 0.05) between peak concentrations of plasma PRL and TRH stimulation and plasma T3 but not T4 levels was observed. These data suggest that a sex difference in TRH-stimulated PRL secretion appears around puberty and that plasma PRL response to TRH is suppressed in children with hyperthyroidism. The magnitude of plasma PRL response to TRH is closely correlated with the severity of hyperthyroidism when judged by plasma T3 but not T4 concentrations.

Adolescent↗
PubMed1982

Lung phosphatidylcholine and fasting in male and female rats.

Lung from male and female rats fasted for 4 days were used. Phospholipid, phosphatidylcholine and its molecular species were analyzed in lungs frm these rats and effects of fasting upon the biosynthesis of phosphatidylcholine in lungs from both sexes were determined using radioactive choline. The molecular species of phosphatidylcholine in both male and female rats did not differ with fasting except the monoenoic species. Incorporation of choline into phosphatidylcholine in both male and female rats significantly increased after fasting, but distribution of radioactivity in phosphatidylcholine yielded similar values in each group. These results suggest that the decrease of saturated phosphatidylcholine content after fasting may not be due to specific change in saturated phosphatidylcholine.

Animals↗
PubMed1982

Analytical study of the performance of a multilayer positron computed tomography scanner.

The image-forming performance of multilayer positron tomographs for extended sources is evaluated analytically. The analysis is simplified by "rotation transform," by which three-dimensional photon detection problems are solved by two-dimensional treatment. Event rates of singles, unscattered true coincidence, and a single- and double-scattered coincidence are formulated for a uniform cylinder phantom as functions of various design parameters. Angle factors for Compton scattering and other parameters used in the evaluation are presented. Scatter components in projections and their effect on the reconstructed images are also evaluated. The scatter component in the reconstructed image depends critically on the detector ring radius, phantom radius, method of attenuation correction, etc. When the director radius is relatively small (40 or approximately 45 cm in diameter), the scatter/true ratio at the image center of a 20 cm diameter phantom may be larger than the scatter/true ratio in the event rates. Comparison with experimental data obtained with a head positron tomograph, POSITOLOGICA, showed reasonable agreement both in the total coincidence rates and in the scatter components in the images for a cylindrical phantom of 20 cm in diameter.

Mathematics↗
PubMed1982

Normal-mirrored letter recognition, same-different judgment and cerebral dominance.

Either normal or mirror images of Kana, Kanji and capital letters were presented tachistoscopically in a left or right visual field, and then normal letters were flashed simultaneously at the fixation point. Subjects were trained to give same (formula: see text) or different (formula: see text) judgments to pairs of stimuli. Reaction time (RT) and percentage of errors (PE) were measured. Generally, normal letters with same judgments revealed a right field advantage, while with different judgments, there were not significant laterality differences. In the case of mirrored letters, each of two judgments showed no lateral asymmetries for each kind of letters excepting a left field advantage for mirrored Kana words with different judgments. PE methods tended to produce a right field advantage more consistently than did RT methods.

Adult↗
PubMed1982

Angiographic evidence of left main trunk spasm as a possible cause of syndrome X.

The present case is a 49-year-old female who began to feel a chest pain during exercise 2 years ago. Recently, the chest pain occurred during light exercise as well as at rest. The electrocardiogram during the attack showed remarkable ischemic ST segment depression. No abnormality was found in the coronary cineangiography. She was diagnosed as Syndrome X. However, coronary cineangiography during an attack on another day showed a severe spasm in the left main trunk. Thus, a spasm must be considered as one of the causes of "Syndrome X".

Angina Pectoris, Variant↗
PubMed1982

Mechanism of action of dantrolene sodium, a peripherally acting muscle relaxant.

The mechanism of action of dantrolene sodium, a peripherally acting muscle relaxant, is reviewed. It does not alter action potentials or responses of the contractile proteins to Ca. The amount of Ca acting on the contractile proteins during twitch must, therefore, be reduced, but since Ca uptake by the SR is not altered, Ca release from the SR must be reduced by the drug. Other characteristics of this drug and their clinical implications are discussed.

Action Potentials↗
PubMed1982

Tension-pCa relation and sarcoplasmic reticulum responses in chemically skinned smooth muscle fibers.

Properties of bundles of smooth muscle fibers in which the surface membrane has been rendered highly permeable by chemical treatment (saponin) are described. These preparations are termed chemically skinned smooth muscle fiber bundles. Thin bundles were isolated from guinea pig teniae ceci and skinned in a relaxing solution by treatment with 50 micrograms/ml saponin for 20-30 min. Because Ca2+ sensitivity progressively decreased on repeating contractions or on incubating in a relaxing solution, the tension-pCa (-log10 [free Ca2+]) relationship was determined soon after the skinning by a single contraction in which the [free Ca2+] was increased in a stepwise manner. Unlike skinned skeletal muscle fibers, in skinned smooth muscle fiber bundles the tension-pCa relationship was not affected appreciably by the changes in pH from 6.4 to 7.2, in ionic strength from 0.15 to 0.30 M, or in [MgATP] from 0.4 to 8 mM. The saponin-treated smooth muscle fiber bundles retained a functional sarcoplasmic reticulum (SR). Ca can be loaded in the SR if the [free Ca2+] is in the micromolar range and MgATP is present and can be released by an application of caffeine. Mitochondria also appear to be functional in saponin-treated fibers.

Adenosine Triphosphate↗