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Biomedical subjects

N Oda

Publications and source records attributed to N Oda.

At least 163 records · Page 9Linked to original sources
PubMed1986

Histopathological observation of the heart with diffuse and abnormal proliferation of mitochondria in myocardial cells (mitochondrial cardiomyopathy): report of an adult case.

An autopsy case of idiopathic dilated cardiomyopathy with abnormal proliferation of mitochondria in the myocardial cells is reported. The case is that of a 39-year-old male with congestive heart failure. The heart was 700 g and showed marked dilatation of all cardiac chambers with myocardial fibrosis of the left ventricular myocardium and interventricular septum, especially in the basal portion of the left ventricular posterior wall. Myocardial cells were hypertrophied with a marked increase of fine-granular sarcoplasm, containing numerous mitochondria, seen by electron microscopy. The mitochondria were usually round or oval and ranged in size from 0.3 to 1.2 micron in diameter. The cristae of these mitochondria frequently showed a concentric lamellar or reticular configuration. Myofibrils were unusually scarce, but the sarcomere structure and arrangement of myofilaments were well-preserved. Epicardial and intramural coronary vessels were almost normal. From these findings, we consider this to be an adult case of mitochondrial cardiomyopathy.

Adult↗
PubMed1986

Radiation quality of tritium beta-rays: microdosimetric distributions for nanometer-size targets in a medium containing tritiated water.

To elucidate the characteristics of the action of tritium beta-rays, the following parameters are derived: electron slowing down spectra of primary electrons (beta-rays) and delta-rays in a medium containing tritiated water; and frequency distributions for the microdosimetric quantity j (number of effective primary events per track per target), fj, for nanometer-size targets exposed to tritiated water. Features of the radiation quality of tritium beta-rays are discussed by comparing the present results with those for 60Co gamma-rays and 7 MeV electrons. It is concluded that, although tritium beta-rays, 60Co gamma-rays, and 7 MeV electrons are classified as the same low l.e.t. radiation, the radiation quality of tritium beta-rays is considerably different from those of 60Co gamma-rays and 7 MeV electrons, and has specific features such as a high average l.e.t., a small total electron fluence per unit absorbed dose, and a different microdosimetric distribution, fj, for nanometer-size targets.

Beta Particles↗
PubMed1986

Interactions of Trimeresurus flavoviridis phospholipase A2 and its N-terminal octapeptide-removed and p-bromophenacylated derivatives with acridine and anilinonaphthalene dyes.

Interactions of dimeric Trimeresurus flavoviridis (the Habu snake) phospholipase A2 (PLA2), des-octapeptide(1-8)-PLA2 (L-fragment) (14% of PLA2 activity), and p-bromophenacyl bromide (BPB)-inactivated PLA2 (BP-PLA2) with dyes, namely, proflavine, 1-anilinonaphthalene-8-sulfonate (Ans), and 2-toluidinylnaphthalene-6-sulfonate (Tns), were investigated. All dyes were bound in a 1:1 molar ratio to the subunit of the proteins. Proflavine was bound most strongly to PLA2 and Ans and Tns were bound to the three proteins with comparable affinities. Capabilities of the dyes for inhibiting alkylation of His-47 of PLA2 with BPB were in the following order: Ans greater than proflavine greater than Tns. Fluorescences of Ans and Tns that were increased in the presence of PLA2 were further greatly enhanced upon the addition of Ca2+, with concomitant formation of the ternary complexes. Ca2+, however, inhibited, competitively or noncompetitively, the bindings of the dyes to PLA2. All dyes were bound to the active site of PLA2 but with different orientations. Inactivation of L-fragment with BPB was inhibited by the dyes in the following order: Tns greater than proflavine approximately Ans. Addition of Ca2+ to the binary complexes formed from L-fragment and Ans or Tns caused no additional enhancement of fluorescence in spite of the formation of the ternary complexes. The active site structures are different between PLA2 and L-fragment, and the N-terminal octapeptide moiety of PLA2 possibly plays a role in maintaining the optimally arranged active site structure of the molecule. Comparison of the data suggests that the N-terminal moieties of PLA2S from snakes of an elapid family and from mammalian pancreas are essential for catalysis of a micellar substrate, whereas those of PLA2S from snakes of a viperid family, such as T. flavoviridis, are not. BP-PLA2 bound Ca2+ and was similar to L-fragment in terms of the fluorescence measurements. It appears that the active site of PLA2 has a space large enough to accommodate p-bromophenacyl, Ans or Tns, and Ca2+ together. Comparison of the emission maxima of Ans and Tns complexed with the three proteins indicated that Tns could be a useful fluorescent probe informing us of the state (disorder) of the active site of PLA2.

Acetophenones↗
PubMed1985

Theory of survival of bacteria exposed to ionizing radiation. I. X and gamma rays.

A new model for the survival of bacteria exposed to ionizing radiation is constructed in the framework of a target theory based on microdosimetric concepts, where single- and double-strand breaks of DNA and their repair in vivo can be described consistently in terms of the microdosimetric quantity j (number of effective primary events per track per target). In this model, the ability of cells to repair DNA damage is taken into consideration in terms of the repair capacities for single- and double-strand breaks of DNA, xi 1 and xi 2 (0 less than or equal to xi 1, xi 2 less than or equal to 1). To apply this model to Escherichia coli K-12 strains with different repair abilities, values of the repair capacity for single-strand breaks, xi 1, were derived from experimental survival curves. The theoretical survival curves for 60Co gamma rays were found to be effectively insensitive to the value of xi 2. Experimental survival curves for the wild-type, uvr, and rec strains of E. coli K-12 were well reproduced in this model. From these results, it is concluded that the theoretical formulation for the survival fraction of bacteria can afford a quantitative method for analysis of the repair process for radiation-induced single-strand breaks in DNA in vivo.

Bacteria↗
PubMed1984

Conduction study in human muscle fibers in situ--a useful technique for diagnosing myopathies.

Direct muscle conduction studies were carried out using monopolar needle electrodes in the distal portion of the brachial biceps muscles in 13 normal and 10 myopathic subjects. Two monopolar Teflon-coated needles with exposed tips were placed as stimulation electrodes in the distal end of the biceps muscle. A pick-up monopolar electrode was then placed 4 cm proximal to the stimulation electrodes along the same muscle with a surface reference electrode in the vicinity of the active electrode. After the maximal evoked response was detected, the shape, amplitude and duration were recorded. The results revealed that the muscle conduction velocity was slower in polymyositis patients compared with normal subjects but was not significantly different in patients with progressive muscular dystrophy. However, the shape, amplitude and duration of the muscle-evoked potential were characteristic in the myopathies. It is concluded that this muscle conduction study technique is simple and of clinical use in making electrodiagnosis.

Action Potentials↗
PubMed1984

Behavioural genetics of early childhood: fears, restlessness, motion sickness and enuresis.

Seventy-nine pairs of same-sex twins were examined at the age of three years at a municipal clinic and their mothers were interviewed to assess the twins' current and past behaviours. The zygosity was determined after the interview by fingerprints and/or bloodtyping in the majority of cases. The following significant differences in concordance between monozygotic and dizygotic twins were found: fear of strangers during observation at the clinic; marked fear of strangers in the first year of life; whether or not the child was startled by sudden noises during infancy; whether or not the child was able to sleep alone at three years without a parent sitting nearby; susceptibility to motion sickness; nocturnal enuresis; short attention span or restlessness during the test.

Child Behavior Disorders↗
PubMed1984

Natural history and predictive significance of head-banging, head-rolling and breath-holding spells.

A five-year follow-up study of children who had had spells of head-banging or breath-holding at three years was carried out to see whether these symptoms have any behavioural sequelae. Of 36 children with breath-holding spells at three years, none still had them. 34 children had had spells of head-banging, and three still had the symptom at follow-up. The children with a history of head-banging were more restless and emotionally unstable at follow-up, but there was no significant difference between the index groups and their controls in other problems of behaviour or development.

Affective Symptoms↗
PubMed1984

Microdosimetric distributions for nanometer-size targets in water irradiated with 60Co gamma rays: frequency distributions of effective primary events by individual tracks of electrons.

A calculation method of frequency distributions for the microdosimetric quantity j (number of effective primary events per track per target), fj , is presented. fj distributions are calculated for nanometer-size targets in water irradiated with 60Co gamma rays, using degradation spectra of total electrons in water, phi t(E). Further, fractional total electron differential fluences effective to produce j effective primary events, phi t(E, j), are calculated. It is found that the frequency for occurrence of no effective primary event tracks (tracks traversing the target without any effective primary event inside the target) is very large for nanometer-size targets, and that the delta-ray effect on the fj distribution becomes more significant with the decrease of the target size and especially j effective primary events (j greater than or equal to 1) for very small targets are due mostly to delta rays.

Cobalt Radioisotopes↗