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Biomedical subjects

T Itakura

Publications and source records attributed to T Itakura.

At least 199 records · Page 11Linked to original sources
PubMed1981

The association of intracranial aneurysms and arteriovenous malformation of the brain. Case report.

A case of intracranial multiple aneurysms associated with an arteriovenous malformation (AVM) is described. Three aneurysms were found arising from an enlarged anterior cerebral artery feeding an AVM. In spite of the fact that two of these aneurysms received no surgical treatment, they disappeared almost completely several months after excision of the AVM. Seventy-three previously reported cases of cerebral aneurysms associated with AVM's are reviewed, and the effect of hemodynamic stresses on the development of these aneurysms is summarized.

Adult↗
PubMed1981

Intracortical spread of exogenous catecholamines: effective concentration for modifying cortical plasticity.

The present study is aimed to clarify the question of maximal intracortical spread of locally perfused 6-hydroxydopamine (6-OHDA) and norepinephrine (NE) through a continuous microperfusion system. The following analyses were performed: 1) catecholamine (CA) fluorescence histochemistry in 6-OHDA-perfused cortex, 2) spatial distribution of tritium counts in the visual cortex perfused either with [3H]-6-OHDA or with [3H]N# and 3) chemical assay of endogenous CAs in 6-OHDA-perfused cortex. 4) High voltage paper electrophoresis was also used to separate unchanged NE from NE metabolites in cortex samples perfused with [3H]NE. Taking the present results together with those in previous physiological assays of cortical synaptic plasticity, we calculated the lowest effective concentration of 6-OHDA for depletion and of NE for restoration of synaptic plasticity in kitten visual cortex: it was approximately 3 microM for 6-OHDA and 0.3 microM for NE, respectively. This concentration of 6-OHDA seems to be low enough for its specific uptake by CA-containing nerve terminals in the visual cortex. The effective concentration of NE appears to be close to or less than the endogenous level of NE per unit of volume of the normal cortical tissue. In addition, by comparing the size of chemical lesions placed by 6-OHDA perfusion in the visual cortex and the spatial distribution of endogenous NE in cortical tissues which had been treated similarly with 6-OHDA, we evaluated the lower limit of sensitivity of a modified glyoxylic acid-perfusion histofluorescence method for visualizing CA (mostly NE)-containing fibers and terminals. The threshold of sensitivity seemed to be 20% of the control.

Animals↗
PubMed1980

The prospects for amino acid infusion.

Amino acid preparations for intravenous infusion are indispensable materials in parenteral nutrition. We have surveyed the progress and problems related to such preparations. In recent years, the necessity of various amino acid preparations suitable for different morbid state and/or ages has been the subject of much interest. In practice, several new amino acid preparations for specific uses have been proposed.

Administration, Oral↗
PubMed1979

Thiamin and pyridoxine requirements during intravenous hyperalimentation.

Studies were undertaken to determine rational dosages of vitamin B1 and B6 during long-term intravenous hyperalimentation, using more sensitive techniques than formerly used to evaluate B1 and B6 status. A standard vitamin combination, type A, (usually commercially available products) has been used up to now because of convenience, disregarding the effects of long-term administration. This combination lacks biotin, folic acid, and vitamin E and contains from 10 to 100 times the dietary allowances of such vitamins as B1, B2, B6, B12, and C. In response to the possibility of vitamin overdose, two new vitamin combinations, type B (from commercial products) and type C (a convenient and easily administered combination produced at the hospital) were developed in order to provide the normal dietary allowances and at the same time eliminate any harmful side-effects. From the results obtained, 5 mg/day for thiamin HCl and 3 mg/day for pyridoxine HCl in type B and type C were found to be a sufficient and safe level as opposed to 55 mg/day for thiamin HCl and 102 mg/day for pyridoxine HCl in type A.

Adult↗
PubMed1978

Organization and projections of the neurons in the dorsal tegmental area of the rat.

The organization and projection of the neurons in the dorsal tegmental area at the locus coeruleus level of the rat have been investigated by means of the horseradish peroxidase (HRP) method, combined with monoamine oxidase staining to identify the noradrenaline (NA) neurons. Judging from the anatomical aspects elucidated in this study, this area is composed of various different cell groups. Although the functional role of these neuronal groups remains to be determined, the present study strongly suggests that the dorsal tegmental area participates in important regulation of several brain functions.

Animals↗
PubMed1977

Fine structure of noradrenaline containing nerve fibers in the median eminence of female rat demonstrated by in situ fixation of potassium permanganate.

Fine structure of noradrenaline (NA) terminals in the internal layer of the median eminence (ME) was elucidated by in situ fixation of potassium permanganate. The NA terminals in ME contained relatively large cored vesicles (about 1000 A) together with a large number of small core vesicle (400-600 A). The most dominant feature that NA terminals show is the closed contact with ependymal cells and their processes. In the bulging abutting on the contact membrane, some of core vesicles fused or touched the membrane appearing to release the content into intercellular space or take up NA from the space. This finding shows that the NA terminals abutting on the ependymal cells and their processes have a close contact with them and give an important influence on regulation of ependymal function. Our present study further revealed that the NA terminals also had a close contact not only with the axon terminals in which ordinary spherical non-cored vesicles were exclusively present but also with the axonal fibers of neurosecretary system. These findings would infer complicated function of NA in ME.

Animals↗
PubMed1976

Skin lesions during intravenous hyperalimentation: zinc deficiency.

Of 54 patients who received prolonged intravenous hyperalimentation during the past 4 years, six developed progressive, characteristic skin lesions. These cutaneous manifestations frequently were accompained by abdominal symptoms resembling those of acrodermatitis enteropathica in many respects. In the first four of these six patients, skin eruptions disappeared promptly after the initiation of oral feeding, which led us to assume that these skin manifestations are due to some unknown nutrient deficiency. Our experience in the remaining two patients enabled us to presume the underlying pathology to be zinc deficiency.

Adult↗