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Biomedical subjects

S Wada

Publications and source records attributed to S Wada.

At least 469 records · Page 26Linked to original sources
PubMed1982

Mammary carcinoma induced by a series of intragastric intubations of 7,12-dimethylbenz[a]anthracene in gonadectomized female and male Sprague-Dawley rats.

Biweekly intragastric intubations of 7,12-dimethylbenz[a]anthracene (DMBA) rapidly induce mammary carcinoma in high yield in gonadectomized female and male rats. These tumors are ovary-independent, though they contain estrogen receptors (ER). In 84.4% of 32 female rats and in 100% of 35 male rats which were gonadectomized at 27 days of age and given 10 mg of DMBA 8 times at 14-day intervals starting from 28 days of age, mammary carcinoma developed 102.4 +/- 28.1 (SD) and 107.2 +/- 25.5 (SD) days, respectively, after the first intubation of DMBA. More than 55% (55 approximately 83%) of seed tumors taken from 18 tumors induced in ovariectomized rats and 18 tumors induced in orchiectomized rats could grow in intact and ovariectomized females and intact and castrated males. Cytosol ER were found in all of 10 tumors induced in gonadectomized male and female rats.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1981

The dose of nicorandil in men predicted from the inhibition of MAO activity by organic nitrates.

The effect of N-(2-hydroxyethyl)-nicotinamide nitrate ester (nicorandil) on rat heart monoamine oxidase (MAO) was investigated in vitro. MAO activity was assayed by the isotopic method with 14C-tryptamine as substrate. Nicorandil significantly inhibited MAO activity of rat heart mitochondria. The effect of nicorandil on the enzymatic kinetics of MAO of rat heart mitochondria indicates that the anti-anginal drug acts as a competitive inhibitor of MAO. The inhibitor constant (Ki) of nicorandil was 4.93 mmol/l. The Ki of nicorandil was fitted to the formula derived from the relationship between the Ki values of glyceryl trinitrate, erythrytol tetranitrate, mannitol hexanitrate and isosorbide dinitrate and the dose of these drugs recommended to relieve anginal pain in patients. The dose of nicorandil was 0.071 mmol (15.0 mg at a time). This value agreed with the clinical dose for patients (10--20 mg at a time).

Animals↗
PubMed1980

Three types of reticular neurons involved in the spino-bulbo-spinal reflex of cats.

Reticular neuron activity was recorded in 28 chloralosed cats in order to analyze the reflex arc of the spino-bulbo-spinal (SBS) reflex. Three types of reticular neurons, types I (input), II(output) and III (relay), were identified by unit discharges in response to stimulation of the sural nerve. (1) Type I (input) neurons received spinal ascending volleys monosynaptically and responded to stimulation of the sural nerve with spikes of low amplitude and short latency. Unit spikes, however, were not produced by stimulation of the superficial radial nerve and the sensorimotor cortex. These input neurons were located in the dorsocaudal part of the medial bulbar reticular formation. (2) Type II (output) neurons were part of the reticulospinal tract, which sends axons to the spinal cord, since these neurons exhibited antidromic spikes following stimulation of the ventrolateral funiculus of the spinal cord. Unit spikes were evoked by stimulation either to the sural or superficial radial nerves. These neurons were located in the ventrocaudal part of the medial bulbar reticular formation. (3) Type III neurons included relay neurons. Unit spikes were evoked by stimulation of the sural nerve, superficial radial nerve and sensorimotor cortex. However, unit discharges were not obtained by antidromic stimulation to the reticulospinal tract. These neurons were distributed widely in the brain stem, both in the bulb and pons. (4) Latency difference of unit discharges between input and output neurons was 3.5--5 msec, indicating the presence of interneurons (relays) between input and output neurons. Spikes of output neurons with 3.8--4.2 msec latency were observed following stimulation of the region where input neuron activity was found. We may conclude that three kinds of reticular neurons, input, relay and output, were involved in pathways of the SBS reflex.

Afferent Pathways↗
PubMed1979

[Primary interhemispheric subdural abscess--case report (author's transl)].

A case of primary interhemispheric subdural abscess was reported, which was not accompanied by abscess formation in other places such as subdural spaces of the convexity or in the brain. A 13-year-old school boy was admitted with 8 days' history of fever, headache and progressive weakness of the left lower extremity. Prior to admission he developed 2 spells of jacksonian seizure initiating from the left leg. Right carotid angiography was performed on admission and separation of the pericallosal and callosomarginal arteries with small avascular area was shown indicating possible abscess formation in the interhemispheric fissure. There was no evidence of purulent infection in the laboratory findings including the CSF and EEG showed diffuse slow wave discharge, more in the right frontocentral leads. He was placed on the vigorous treatment with antibiotics and steroids, and one month later the left lower weakness as well as the EEG abnormality showed some improvement. However, the separation of the anterior cerebral arterial branches became more prominent and formed a lens shaped avascular area, although the pericallosal artery was in the midline. A diagnosis of interhemispheric subdural abscess was made and was confirmed by surgery. Patient showed progressive recovery of the left lower paralysis, and the abscess was totally collapsed in the repeated angiographic follow-up study. Angiographic characteristics of the interhemispheric subdural abscess were described and particular emphasis was placed on the peculiar neurological symptoms referring to the previous reports in the literature.

Adolescent↗