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Biomedical subjects

K Nakai

Publications and source records attributed to K Nakai.

At least 343 records · Page 19Linked to original sources
PubMed1985

[Assessment of regional wall motion of the hypertrophic heart by phase analysis of thallium-201 images].

Combined technique with gated planner thallium (Tl)-201 images and gated cardiac pool images were applied to evaluate cardiac hypertrophy and regional wall motion for 13 persons. These subjects consisted of four normal persons, four patients with hypertrophic obstructive cardiomyopathy (HOCM) and five patients with asymmetrical apical hypertrophy (AAH). The Tl-201 image and cardiac pool image were obtained using the gated technique, in which the R-R interval was divided into 16 parts, in the 30 degree left anterior oblique projection. The region of interest (ROI) in the left ventricle was defined by the threshold method and radially divided into 16 segments in the center of the left ventricular area. The count ratio, considered as an indicator of regional myocardial contractility, was calculated using the formula (EDC-ESC/EDC) in each ROI. The functional image and histogram, an indicators of the synchronization of left ventricular wall motion, were constructed by the fluctuation of the phase distribution in volume curves of Tl-201. These indicators were evaluated for the normals and the two groups of patients. The count ratio indicated a higher value in the region of the left ventricular free wall and the cardiac apex in the normals, HOCM and AAH. The count ratio at the septal region indicated a lower value in HOCM, in spite of marked septal hypertrophy. A significant fluctuation of the phase distribution was demonstrated in the septal region in HOCM, and also at the apical region in AAH.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1984

Accelerated regeneration of central catecholamine fibers in cat occipital cortex: effects of substance P.

Remarkably fast regeneration of central noradrenaline (NA) fibers was recently observed in the 6-hydroxydopamine (6-OHDA)-perfused occipital cortex. In the present study, we found that this reinnervation by NA fibers was further accelerated by substance P (SP) perfused into the fourth ventricle but not by SP directly perfused into the cortex. The site of SP's action is therefore most likely located in the soma-dendritic area of NA cells in the locus coeruleus (LC). The regeneration-stimulating effect of SP seems to be mediated by a process specific to SP, since the similar treatment with bethanechol in place of SP was ineffective.

Animals↗
PubMed1984

A light and electron microscopic immunohistochemical study of vasoactive intestinal polypeptide- and substance P-containing nerve fibers along the cerebral blood vessels: comparison with aminergic and cholinergic nerve fibers.

Vasoactive intestinal polypeptide (VIP)- and substance P-containing nerve fibers were observed in the cerebral blood vessels using an immunohistochemical technique. VIP-containing nerve fibers distributed in a spiral pattern, similar to that of muscle cells. Under electron microscopic observation, VIP-immunoreactive terminals lay close to a muscle cell in the inner layer of the adventitia. In contrast, substance P-containing nerve fibers showed a meshwork pattern in the outer layer of the adventitia. Using both acetylcholinesterase (AChE) staining and VIP immunohistochemistry, AChE-positive and VIP-immunoreactive nerve fibers revealed almost the same distribution in the same specimen. The present data suggest that VIP-containing nerve fibers may play a role in the smooth muscle control of the blood vessels, whereas substance P-containing nerve fibers may not take part in muscle control.

Animals↗
PubMed1984

Aminergic innervation of cerebral veins. Histochemical comparison with extracranial veins.

The density and distribution pattern of aminergic nerve fibers in intracranial and extracranial veins were compared by means of catecholamine histofluorescence studies. Extracranial veins (internal jugular, inferior caval, portal, renal, internal iliac, and femoral veins) showed quite a uniform distribution pattern. Large veins (jugular, caval, renal, and iliac veins) revealed a spiral pattern, and small veins presented as a meshwork (femoral vein) or in a longitudinal pattern (a branch of the femoral vein). In contrast, intracranial veins displayed more complex patterns: the dural sinus showed a longitudinal pattern and the internal cerebral vein and the superficial vein of Labbé revealed a meshwork of nerve fibers. The aminergic fibers were denser in cerebral veins (dural sinus and internal cerebral vein) than in extracranial veins. The complex distribution and the density of aminergic fibers in cerebral veins suggest that the aminergic innervation of the circulatory system may be more important in the brain than in the extracranial organs.

Amines↗
PubMed1984

[Morphological study on innervation of the cerebrospinal blood vessels. II. Spinal blood vessels].

The distribution patterns of aminergic and cholinergic nerve fibers in the feline spinal blood vessels were studied by means of amine histofluorescence and acetylcholinesterase (AChE) staining. The anterior spinal artery had a dense network of aminergic and AChE-positive (probably cholinergic) nerve fibers. The posterior spinal vein, in contrast, had only aminergic nerve fibers. Intraparenchymal small blood vessels in the spinal cord also had strongly fluorescent (probably peripheral) aminergic nerve fibers. This was quite a characteristic feature in the spinal cord. The distribution pattern and the density of these two sorts of nerve fibers widely varied with the individual segment of the spinal cord. The thoracic spinal cord had the lowest number of these nerve fibers throughout the spinal cord. This fact may give a clue to explain why the thoracic spinal cord is most susceptible to ischemic change.

Acetylcholinesterase↗
PubMed1984

[Peptidergic innervation of the cerebral blood vessels--an immunohistochemical study].

By an immunohistochemical technique, vasoactive polypeptide (VIP)-and substance P-containing nerve fibers are observed in the cerebral blood vessels. VIP-containing nerve fibers distribute in a spiral pattern, similar to the muscle cell distribution pattern. Under an electron microscopic observation, VIP-immunoreactive terminals lie just near to a muscle cell in the inner layer of the adventitia. In contrast, substance P-containing nerve fibers show a meshwork pattern in the outer layer of the adventitia. In combination of acetylcholinesterase (AChE) staining and VIP immunohistochemistry, AChE-positive and VIP-immunoreactive nerve fibers reveal almost same distribution in the same specimen. The present data suggest that VIP-containing nerve fibers may play a role of smooth muscle control of the blood vessels, while substance P-containing nerve fibers may not take part in muscle control.

Animals↗
PubMed1984

[Morphological study on innervation of the cerebrospinal blood vessels. I. Cerebral blood vessels].

The distribution of nerve fibers in the cerebral blood vessels was studied by a catecholamine histofluorescence method, acetylcholinesterase (AChE) staining and immunohistochemistry. The ultrastructure of the terminal boutons in the vessel wall was also studied. In the adventitia of the cerebral artery, green fluorescence aminergic fibers and brownish AChE-positive (probably cholinergic) fibers were observed. In contrast, the cerebral venous system showed no AChE-positive fibers. The highest density of aminergic fibers were found in the dural sinus and the second highest in the internal cerebral vein. Serotonin immunoreactive nerve fibers were found along small intraparenchymal blood vessels such as perforating arteries in the brain stem, and arterioles and venules in the cerebral cortex. Under ultrastructural observation, a serotonin immunoreactive terminal was demonstrated in conjunction with the basement membrane of the capillary.

Acetylcholinesterase↗
PubMed1983

Spontaneous subperiosteal hematoma of the orbit.

Spontaneous subperiosteal hematoma of the orbit is extremely rare. This is a case of an 81-year-old woman. The presenting symptom was protrusion of the right eye with severe intraorbital pain. Computed tomography scanning showed a high-density area in the upper part of the right orbit, which, at operation, was found to be a subperiosteal hematoma of the orbit.

Aged↗
PubMed1983

In vivo release of testosterone from vinyl polymer composites prepared by radiation-induced polymerization.

Polymer-testosterone composites with long periods of controlled slow release were made by radiation-induced polymerization in a supercooled state at low temperature using glass-forming monomers. The in vitro release of testosterone from various vinyl polymer composites was found to follow a matrix-controlled process (Q-t1/2). The rate of drug delivery was accelerated with increasing water content of polymers. In experiments in vivo, the composites were implanted subcutaneously in the back of castrated rats during the 30 day test period. The in vivo release rate of testosterone was a little smaller than in vitro. This difference between two releases also increased with the increase of hydrophilicity of polymer. The physiological response in rats was investigated by measuring the weight of ventral prostate and serum testosterone concentration with testosterone-containing composites. The weight of ventral prostate increased linearly with increasing rate of drug release and the serum testosterone concentration could be correlated with the release and with the weight increase of ventral prostate. It was found from microscopic observation that the used polymer carriers had relatively good biocompatibility to cause little foreign body reaction.

Animals↗