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Biomedical subjects

N Suenaga

Publications and source records attributed to N Suenaga.

At least 37 records · Page 2Linked to original sources
PubMed1990

[Severe bronchial reaction induced by hydrocortisone sodium succinate in an aspirin-sensitive asthmatic patient].

This is a report of a female patient who had an anaphylaxis-like reactions to hydrocortisone sodium succinate (Saxizon). A 31-year-old female with intrinsic bronchial asthma and aspirin sensitivity was admitted to our hospital because of an episode of asthmatic attack. The patient had had episodes of dyspnea since 1976, and had been treated with oral bronchodilators and intermittent corticosteroids. After admission, she was given 100 mg of hydrocortisone sodium succinate intravenously. A few minutes later she developed severe bronchospasm and lost consciousness. An endotracheal tube was inserted and she was mechanically ventilated for 2 hours. The patient recovered after 1 hour. An inhalation challenge test with Sulpyrin was positive. When the provocation challenge test with 100 mg of hydrocortisone sodium succinate (Saxizon) injection was performed, she developed subjective and objective evidence of bronchospasm. Intradermal skin test revealed positive immediate reactions to Saxizon, Solu-cortef, Predonine. It is suggested that she had immediate hypersensitivity to hydrocortisone sodium succinate, but the mechanism of this anaphylaxis-like reaction to steroids is not certain.

Adult↗
PubMed1984

A 26K fragment of troponin T from rabbit skeletal muscle.

A 26K fragment of troponin T, which was produced by endogenous proteases in rabbit skeletal muscle, was isolated by SE-Sephadex column chromatography. This fragment sensitized both superprecipitation and ATPase of actomyosin to calcium ions, to the same extent as troponin T. There was no difference in affinity for tropomyosin between this fragment and troponin T as examined by affinity chromatography. Amino acid analysis showed that this fragment consisted of residues Ala-46-Lys-259 of troponin T. The N-terminal 45 residues of troponin T, therefore, are not essential for the physiological action of troponin T. It was also observed that Ca2+-activated neutral protease digested troponin T into the 26K fragment in the native thin filament, while the protease digested troponin T in a different way in the reconstituted thin filament.

Amino Acids↗
PubMed1983

Infantile digital fibromatosis. Identification of actin filaments in cytoplasmic inclusions by heavy meromyosin binding.

Cell cultures were carried out from four patients with infantile digital fibromatosis. The cultured cells, which contained cytoplasmic inclusions identical to those of the original tumor cells, possessed cortical bundles of microfilaments, rich network of granular endoplasmic reticulum, and well-developed Golgi complex. To demonstrate the distribution of actin filaments in the cultured cells, the heavy meromyosin-binding method was applied to saponin-treated cells from one of the four patients. The microfilaments constituting the inclusions as well as the cortical bundles were decorated with heavy meromyosin, presenting the "arrowhead complexes" specific for actin filaments. The inclusion may represent abnormal contraction of actin filaments in the cytoplasm of myofibroblasts.

Actins↗
PubMed1982

Effect of troponin and tropomyosin on the interaction between cytochalasin B and actin filaments.

Effects of troponin (TN) components and tropomyosin (TM) on the interactions between actin filament and cytochalasin B (CB) at low ionic strength were investigated using electron microscopy and viscometry. CB decreased the viscosity of the actin filament and this effect became apparent at 10 microM CB and reached the maximum at 40 microM. CB (40 microM) shortened the average actin filament length from 0.50 to 0.25 micrometers as observed electron microscopically. Presence of TN components and TM diminished the effect of CB on both viscosity and filament length. TN-T but not TN-I had an inhibitory effect on the decrease of the viscosity of the A+TM filament induced by CB. TN-T1 but not TN-T2, one of two chymotryptic subfragments of TN-T, had the same inhibitory effect seen with TN-T. Thus, the cooperation between the T1 region of TN-T and TM is probably essential for the inhibitory action on CB-actin interactions.

Actins↗
PubMed1982

The role of the locus coeruleus in regulation of seizure susceptibility in rats.

When studying the role of the locus coeruleus (LC) in the regulation of seizure susceptibility in rats, we found that bilateral LC lesion significantly lowered the electroshock seizure threshold for the tonic extension of forelegs. The pattern of maximal electroshock seizure was not affected by LC lesion, although the recovery time was slightly prolonged. In the pentylenetetrazol (PTZ) seizure threshold test, LC lesion significantly elevated the twitch threshold, but did not affect the threshold for the generalized clonic seizure or clonic convulsion. Incidence of the tonic extension in the PTZ seizure test tended toward an increase with LC lesion. Biochemical determinations revealed that LC lesion significantly decreased the norepinephrine contents in various brain regions as well as the 5-hydroxytryptamine contents of some brain regions, but not the 5-hydroxyindoleacetic acid contents. These results suggest that while the LC is involved in the regulation of seizure susceptibility, the involvement differs with various types of seizures.

Animals↗
PubMed1979

The role of locus coeruleus in decapitation convulsions of rats.

The role of the central norepinephrine (NE) system, especially the locus coeruleus (LC), in the occurrence of decapitation convulsions was investigated in rats. Intraspinal injection of 6-hydroxydopamine (6-OHDA) caused a significant inhibition of decapitation convulsions as shown by prolongation of the latency and shortening of the convulsion's duration, as well as decreasing the NE content of the spinal cord to 35% of the control value without affecting the NE content of the various regions in the brain. Chemical lesion of the descending bundle from the LC by treatment with 6-OHDA significantly inhibited decapitation convulsions in a similar manner. Moreover, there was a decrease in the NE content of the spinal cord and hypothalamus to 24% and 47% of the control value, respectively. Bilateral electrolytic lesion of the LC also significantly inhibited decapitation convulsions and decreased the NE content of the cortex and spinal cord to 15% and 74% of the control value, respectively. However, lesions of the dorsal and ventral NE bundle by treatment with 6-OHDA, which caused a marked decrease in the NE content of the cortex and hypothalamus, respectively, did not affect the decapitation convulsion. Intraspinal injection of 5,6-dihydroxytryptamine resulted in a decrease in the 5-hydroxytryptamine content of the spinal cord only; moreover, it did not change the decapitation convulsion. These results suggest that coeruleospinal NE neurons play an important role in the occurrence of decapitation convulsions.

5,6-Dihydroxytryptamine↗
PubMed1979

Possible involvement of brainstem norepinephrine in pentylenetetrazol convulsions in rats.

The thresholds of twitch and clonic convulsion induced by intravenous infusion of pentylenetetrazol (PTZ) were measured in rats treated with 6-hydroxydopamine (6-OHDA). In adult rats, intraventricularly applied 6-OHDA increased susceptibility to PTZ convulsions and decreased norepinephrine (NE) contents of the cortex, hypothalamus and brainstem. When 6-OHDA was applied intraventricularly at 8 days after birth, PTZ convulsion susceptibility was slightly decreased and brainstem NE content was significantly increased. However, the effects of 6-OHDA given at 20 days after birth were similar to those observed in adults. Significant decrease of cortical and hypothalamic NE contents, but no change in PTZ convulsion susceptibility, occurred following 6-OHDA injections into the dorsal and ventral NE bundles. These results suggest that the brainstem NE neurons play an inhibitory role on the development of PTZ convulsions.

Animals↗
PubMed1977

Changes in spontaneous activity and emotional responses of rats treated with 6-hydroxydopamine at the suckling age.

Spontaneous activity and emotional responses in mature rats treated with 6-hydroxydopamine (6-OHDA: 100 microgram X 2) injected into their left and right lateral ventricles during the suckling age (12th and 15th day of birth) were investigated. The 6-OHDA treated rats showed normal growth and no significant change in the norepinephrine levels of peripheral organs despite a marked and long-lasting decrease of catecholamine levels in the central nervous system. In the open field test, ambulation and rearing within 3 min were not altered by 6-OHDA treatment whereas a significant decrease in ambulation was noted in the treated rats during continuous 30 min observation. The running-wheel activity of the treated rats was significantly lower than that of control rats during 10 days of continuous observation. Methamphetamine (1 mg/kg s.c.) produced a marked increase of activity in both groups, but the activity of the treated rats was significantly higher than that of the control rats. In the emotional response test, an increased startle response to tail pinching was observed in the 6-OHDA treated rats. Thr results showed that compensatory mechanisms following destruction of catecholamine neurons developed to a considerable extent in the rats injected with 6-OHDA intraventricularly at their suckling age. The possible role of increased activity in the remaining intact or regenerated catecholamine neurons on the compensatory mechanisms was discussed.

Age Factors↗