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Biomedical subjects

H Ashida

Publications and source records attributed to H Ashida.

At least 145 records · Page 8Linked to original sources
PubMed1986

The effect of orally administered secondary autoxidation products of linoleic acid on the activity of detoxifying enzymes in the rat liver.

Radioactive secondary autoxidation products of linoleic acid were administered orally to rats and the incorporation of radioactive substances into lipids was investigated in the liver. The radioactive substances were significantly incorporated into hepatic mitochondrial and microsomal lipids 12 h after the administration. 80% of the radioactivity in mitochondria was detected in neutral lipids. The radioactivity in microsomal neutral lipids significantly decreased and the activity in phospholipids increased 12 h after the administration. On the other hand, contents of lipid peroxide and thiobarbituric acid reactive substances in liver were significantly increased by 40% at 15 h after the administration of the secondary autoxidation products. Activity of marker enzymes used for an indication of the hepatic injury was also elevated. Glutathione peroxidase activity increased 3-fold and catalase activity increased 1.5-fold. Activity of mitochondrial NAD-dependent aldehyde dehydrogenase, however, was decreased by 50%. It seems likely that the secondary autoxidation products orally administered are detoxified in the hepatic mitochondria, metabolized to neutral lipids, and further metabolized to phospholipids in microsomes, while as the incorporated secondary autoxidation products induces hepatic injury by lipid peroxidation.

Administration, Oral↗
PubMed1986

Stochastic description of the three-state model of the Na channel.

The three-state model of the Na channel is formulated stochastically and various observable quantities calculated from this model. This model assumes that the Na channel can occupy one of three states--resting, open and inactivated--and that each channel is independent. This is a simplified representation of the model proposed by Aldrich et al. (1983) mainly with respect to the neuroblastoma. When the system contains many channels, the probability distribution of the numbers of the channels that occupy each of these states is a time-dependent multinomial distribution and the distribution of the first passage time from resting state to open state becomes an exponential decay function with higher components. The average and variance of the channel current calculated by the distribution show the time course with a single peak and its ratio converges to the current of a single channel. Stochastic treatment of the transient process developed here gives a method of estimating all of the transition rates and the number of channels in the system.

Ion Channels↗
PubMed1986

Bronchial artery aneurysm.

Two patients with bronchial artery aneurysm were surgically treated. One patient had a saccular aneurysm in the root of the left bronchial artery, and the other had a mediastinal as well as an intrapulmonary aneurysm, rupture of the latter of which had resulted in massive hemoptysis. Twelve reports of bronchial artery aneurysm have appeared in the literature to date. Those of mediastinal location frequently have symptoms mimicking dissecting aortic aneurysm, whereas their intrapulmonary counterparts usually are manifested by hemoptysis. Although its etiological process remains to be elucidated, this rare entity should be recognized in the clinical practice.

Adolescent↗
PubMed1986

[A case of colon cancer associated with schistosomiasis japonica].

A case of colon cancer associated with schistosomiasis japonica is reported. A 60-year-old man was admitted with the complaint of melena. Barium enema study revealed a colon tumor (type 1') 11 cm from the anal ring. Sigmoidectomy was performed, and no lymph node metastasis was observed. Histologically, the tumor was diagnosed as well-differentiated adenocarcinoma, and also many schistosoma ova were found not only in the lesion of the carcinoma, but also in the tissue surrounding the carcinoma. In the latter lesion, ova were observed beneath muscularis mucosae. The distributions of the ova in the anal side of the tumor were more dominant than those in oral side. We review the direct correlation between gastrointestinal tract cancer and the schistosomiasis japonica in other reports.

Adenocarcinoma↗
PubMed1986

[Percutaneous nephrolithotomy by electrohydraulic shock wave].

Twelve patients underwent percutaneous nephrolithotomy in our hospital. Six of these patients had stone disintegration by electrohydraulic shock wave. The procedure was safe and effective for achieving rapid stone disintegration. Translocation of the stone fragments and central metal core of the probe left in the ureter were clinical problems. However, they passed spontaneously. Usefulness and problems of electrohydraulic lithotripsy were discussed.

Humans↗
PubMed1985

General solution of cable theory with both ends sealed.

General solution of the cable theory with both ends sealed when injecting an arbitrary current at an arbitrary point of the cable is presented, which is a time-dependent transient solution. The solution is an infinite series, each term of which is the product of a cosine term including a position variable only and an exponential term including a time variable only. The general solution contains almost all solutions reported hitherto as particular cases and the mutual relations among the various solutions of quite different forms are clarified by this general solution. Moreover the shorter the cable becomes, the more rapidly this solution converges, therefore it is useful for an analysis of the short cable in the case where the relative deviation error may grow large. The truncation error can also be estimated as the solution is an infinite series of simple functions.

Animals↗
PubMed1984

Field mapping of EEG by unbiased polynomial interpolation.

The technique for field mapping of EEG using interpolation by an unbiased estimator of two-dimensional isotropic higher-order polynomial is developed. Assuming that the observed EEG contains noise, this method permits free positioning of the electrodes and does not reveal artificial oscillations as large as those of the Gibbs' phenomenon as in the case of the widely used Fourier interpolation. In the example of RMS (root mean square) amplitude at anesthesia, the onset of the fast activities began to appear clearly in the frontal and occipital area. By this method, not only RMS amplitude, but also instantaneous amplitude, such as visual evoked potential and somatosensory evoked potential, can be mapped.

Anesthesia↗
PubMed1983

Combined spikes induced by Ca and Na currents in cultured cerebellar neurons from the chick embryo.

Evoked spikes in explanted cerebellar neurons cultured for 17-25 days, presumably including Purkinje cells, were not completely blocked by 10(-5) g/ml TTX. The TTX-resistant components of the spike were suppressed by Co2+ or Mn2+. It is suggested that combined Ca and Na components are involved in spike generation mechanisms in cultured neurons from the chick cerebellum and that they may be related to the maturation process of excitable membranes of cell soma.

Animals↗
PubMed1983

The development of action potentials in cultures of explanted cortical neurons from chick embryos.

Action potentials of explanted cortical neurons from 7- to 9-day chick embryos were investigated at different stages during culturing. The maximum rates of rise of action potentials gradually increased and reached a plateau level at about 1 month in culture. Action potentials were resistant to 10(-7) g/ml tetrodotoxin (TTX) at early stages, became sensitive to TTX in an age-dependent manner, and almost all action potentials were blocked by this concentration of TTX after 25 days. However, 10(-5) g/ml TTX suppressed action potentials at early stages. When action potentials were suppressed by TTX, impulses could still be obtained from immature neurons following addition of 10 mM Ca2+ to the saline. This effect was not observed in mature neurons. The application of 10 mM Mn2+ frequently enhanced action potentials in immature neurons. This effect was not blocked by TTX (10(-5) g/ml) or the removal of external Na+. These results suggest that action potentials in immature neurons depend on Ca2+ and Na+, that Mn2+ can pass through Ca channels, that the sensitivity to TTX develops as the contribution by Na+ becomes greater, and that the contribution by Ca2+ diminishes during maturation.

Action Potentials↗
PubMed1983

Human major psoas muscle and sacrospinalis muscle in relation to age: a study by computed tomography.

The size and density of the major psoas and sacrospinalis muscles in humans were measured in vivo by X-ray computed tomography to determine the relationship of age and sex of these two muscles. Measurements of 44 men and 52 women clarified patterns of development and aging. Differences due to age were significant in the density of both muscles. There existed also a difference between the sexes in the size of the two muscles.

Adolescent↗