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Biomedical subjects

T Ikeno

Publications and source records attributed to T Ikeno.

68 records · Page 4Linked to original sources
PubMed1980

Partial characterization of monoamine oxidase in the salivary gland of rats.

Changes in the substrate specificity of monoamine oxidase in the rat submaxillary gland were examined after ligation of the excretory duct and after denervation by postganglionic sympathectomy. Atrophy of the parenchymal cells after ligation of the excretory duct was observed, but such was not so clear after the denervation. The rate of decreases in the enzyme activity after the duct ligation was highest with serotonin, intermediate with dopamine and tyramine and lowest with beta-phenylethylamine, used as substrates. The proportion of form A monoamine oxidase was examined using clorgyline as an inhibitor specific for form A enzyme; approximately 95%, 90% and 85% of the total enzyme activities were attributed to form A enzyme in the intact glands, in the denervated glands and in the duct ligated glands, respectively. These results indicate that 90% of the enzyme activity in the parenchymal cells and almost of all the enzyme activity in the sympathetic nerves of the gland may be attributed to form A enzyme and the atrophy of parenchymal cells after the duct ligation results in a decrease in form A enzyme more markedly than form B.

Animals↗
PubMed1979

Growth regulation by nerve growth factor.

Although a great deal of descriptive information has been obtained about the actions of nerve growth factor on its target tissues, its structure, its receptors, and even its biosynthesis, there is no clear understanding, as yet, of the intracellular events mediating its transcriptional involvements. Work in this laboratory over the past five years has uncovered a number of nerve growth factor-initiated intracellular changes in sympathetic neurons and other nerve growth factor-sensitive systems, and has provided a framework into which they might fit. This article is written in an attempt to collect the data in a single communication and to suggest at least one mechanism by which the nerve growth factor may work.

Animals↗
PubMed1978

Intraventricular administration of nerve growth factor induces ornithine decarboxylase in peripheral tissues of the rat.

Intraventricular administration of nerve growth factor causes an increase in the activity of ornithine decarboxylase (L-ornithine carboxy-lyase, EC 4.1.1.17) in liver, kidney, and adrenal as well as in brain itself. An increase in the concentration of corticosterone in the blood was also observed. Adrenalectomy, hypophysectomy, or pituitary stalk section inhibits the increase of ornithine decarboxylase activity in the peripheral tissues. Ornithine decarboxylase activity in the brain, however, responds to nerve growth factor in these animals. The data indicate that nerve growth factor causes an acitivation of the hypothalamo-hypophyseal endocrine system.

Adrenal Glands↗
PubMed1977

Purification and properties of human serum dopamine-beta-hydroxylase.

1. Two different molecular forms of dopamine-beta-hydroxylase were isolated from human serum; a major component (Peak I enzyme) with a molecular weight of 368000 and with a higher specific activity and a minor component (Peak II enzyme) with a molecular weight of 188000 and with a lower specific activity. 2. Both forms require ascorbic acid for the activity, and are stimulated by fumarate. Addition of N-ethylmaleimide or copper also increased the activity. The optimal pH of both forms in the presence of 20mM tyramine as substrate is 5.0. 3. Km values toward tyramine of Peak I enzyme and Peak II enzyme were 1.67 mM and 14.2 mM respectively. 4. Both Peak I enzyme and Peak II enzyme are glycoprotein.

Animals↗
PubMedDate not supplied

An analytic study of epileptic falls.

The subject of this study was a total of 48 epileptic falls or drop attacks in 15 children, captured by a self-tracking video monitoring system. A fall was defined as a complete loss of the maintenance of either standing or sitting posture, which took place within 1 s. The patients with epileptic falling attacks thus defined fulfilled the diagnostic criteria of Lennox-Gastaut syndrome. Through precise analysis of the ongoing sequence from the onset to the completion of the fall, it was possible to classify them into the following four types: (a) tonic type, 9 falls in five patients; (b) flexor spasms type, 25 falls in eight patients; (c) myoclonic-atonic type, 12 falls in three patients; and (d) atonic type, 2 falls in one patient. In contrast to the generally accepted view, it was found that atonic or myoclonic-atonic falls were rather exceptional. Seven of eight children whose falls were categorized as the flexor spasms type, which is reminiscent of infantile spasms in terms of clinical as well as EEG expressions, in fact experienced in their individual history West syndrome before it evolved to Lennox-Gastaut syndrome. In particular, the extreme pathophysiological complexity of epileptic falls or drop attacks is stressed.

Adolescent↗
PubMedDate not supplied

Retroperitoneal malignant fibrous histiocytoma surgically removed six times using a harmonic scalpel.

This paper describes a patient with retroperitoneal malignant fibrous histiocytoma who underwent surgical removal of the tumor 6 times. It is difficult to remove locally recurrent retroperitoneal malignant fibrous histiocytoma many times by repeat surgery, since the tumor tends to adhere tightly to the surrounding scar tissue. In the 5th and 6th operations we conducted on the patient, a harmonic scalpel was useful for separating the tumor from the scar tissue at the previous surgical site.

Cicatrix↗