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Biomedical subjects

T Sakamoto

Publications and source records attributed to T Sakamoto.

At least 1,207 records · Page 67Linked to original sources
PubMed1978

Studies on anticoccidial agents. 12. Synthesis and anticoccidial activity of methyl-2(6)-nitro- and -3(5)-nitropyridinecarboxamides.

A number of methyl-2- and 3-nitropyridinecarboxamides have been synthesized. It has been established that the presence of at least one hydrogen atom, adjacent to the NO2 function, is important for anticoccidial activity and introduction of a methyl group to the adjacent position of the CONH2 function sometimes confers enhanced activity. Among the compounds herein, 5- and 6-methyl-2-nitropyridine-4-carboxamides possess optimal anticoccidial activity, being as potent as the parent compound.

Coccidiostats↗
PubMed1978

Some new or poorly recognized physical and graphic findings in various forms of pericardial disease.

The eight new items concerning pericarditis (acute pericarditis, acute or chronic pericardial effusion, and constrictive or sero-constrictive pericarditis) were demonstrated based on the clinical observation of 115 patients. Pericarditis, a disease of remote antiquity, still has many fascinating and unrecognized aspects, which will be uncovered by the meticulous observation of the patients.

Adult↗
PubMed1978

[Arrest reaction in man: motor arrest response by electrical stimulation of the deep structure of the cerebrum (author's transl)].

In spite of many reports of arrest reaction in animals, there are very few reports in man. During a therapeutic stereotaxic operation we observed peculiar phenomena caused by electrical stimulation to the deep structure of the cerebrum. This phenomenon is quite similar to that reported by Van Buren, but there are a few differences between them. Arrest reaction was observed in 14 of 23 cases, 17 of 28 tracks. Stimuli which caused the arrest reaction were 60--100 Hz square waves of, 1 msec duration and 5--15 V. The electrical stimulation caused an interruption of counting and other motor actions, which could be resumed following release of stimuli. Psychic confusion or memory disturbances were not observed with the exception of a few cases. The arrest reaction that we observed is thought to be due to a direct effect on the head of the caudate nucleus, not due to secondary effects on the internal capsule and the motor fiber in the vicinity of the caudate nucleus. However, the possibility that the current spread to the motor fiber cannot be definitely ruled out.

Adult↗
PubMed1978

Arrest reaction in man. Motor arrest response by electrical stimulation of the deep structure of the cerebrum.

In spite of many reports of arrest reaction in animals, there are very few reports in man. During a therapeutic stereotactic operation we observed peculiar phenomena caused by electrical stimulation to the deep structure of the cerebrum. This phenomenon is quite similar to that reported by Van Buren, but there are a few differences between them. Arrest reaction was observed in 14 of 23 cases, 17 of 28 tracks. Stimuli which caused the arrest reaction were 60--100 Hz square waves of 1 msec duration and 5--15 V. The electrical stimulation caused an interruption of counting and other motor actions, which could be resumed following release of stimuli. Psychic confusion or memory disturbances were not observed with the exception of a few cases. The arrest reaction that we observed is thought to be due to a direct effect on the head of the caudate nucleus, not due to secondary effects on the internal capsule and the motor fiber in vicinity of the caudate nucleus. However, the possibility that the current spread to the motor fiber cannot be definitely ruled out.

Adult↗
PubMed1978

[Experimental cerebral infarction. Part 1: Production of thalamus infarction model in dogs (author's transl)].

Difficulties in producing temporary cerebral ischemia in experimental animals have delayed the study on the prevention and treatment of cerebral infarction. Although occlusion of the middle cerebral artery in dog proved to be fruitless, we eventually succeeded in producing focal cerebral infarction by temporary occlusions of brain arteries. Infarction confined to the anterior portion of the thalamus was obtained by simultaneous occlusion of four arteries for 60 or 120 minutes: internal carotid, anterior cerebral, middle cerebral and posterior communicating arteries. This experimental model in dogs is unique, since a marked infarction can be seen in high frequency, and the dogs can be managed for sufficient periods after temporary clipping. Consequently, it is possible to investigate cerebral infarction not only from the pathophysiological viewpoint, but also for its prevention and treatment.

Animals↗
PubMed1978

[Effects of bilateral amygdalectomy on levers pressing for food reward in the rabbit (author's transl)].

Effects for continuous reinforcement (CRF) learning and differential reinforcement of low rate (DRL) learning for food in the rabbit by bilateral amygdalectomy were examined with the Skinner box. There was no changes in general behaviour and no impediment of CRF learning. But the completion of DRL learning was delayed by amygdalectomy. In the stage of completion of DRL learning there was no difference of total number of the reinforcement and the lever pressing between the control group and amygdalectmized group. But there was the impediment of DRL learning by the analysis of frequency distribution of inter-response time and of transition probability matrix in the amygdalectimized group. We thought that this impediment of DRL learning was due to the impediment of selection of decision of lever pressing action. The memory of the preamygdalectomy was maintained well after amygdalectomy.

Amygdala↗