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Biomedical subjects

K Fukuda

Publications and source records attributed to K Fukuda.

At least 811 records · Page 45Linked to original sources
PubMed1986

[The results of investigation by the Japanese version of Morningness-Eveningness Questionnaire].

Morningness-Eveningness Questionnaire (MEQ) developed by Horne & Ostberg (1976) was translated into Japanese, and then, MEQ and Life Habits Inventory were administered to approximately 1,500 university students. The distribution of MEQ scores was essentially normal, and the reliability of this questionnaire was high (r alpha = .702). Comparing among the morning, evening, and intermediate types, it was found that the morning type retired and arose significantly earlier than other types, although there was no significant differences in sleep length. Furthermore, there were significant differences between the morning and evening types in sleep latency, mood on arising, adequate amount of sleep, frequency and duration of nap, and number of staying awake all night per month. These results suggested that the evening type had more irregular sleep-waking habits than the morning type. Since the above results were obtained only from student population, further investigation on various populations is requested.

Adult↗
PubMed1986

Stimulation of cardiac slow Ca++ current by high concentration of cimetidine.

Electrophysiological studies on the cardiac effects of a H2-antagonist, cimetidine, were examined in three kinds of preparations: guinea-pig papillary muscles, rat left atria and perfused chick hearts. Cimetidine (10(-5) to 10(-4) M) depressed or abolished the slow action potentials (APs) induced by histamine (10(-5) to 10(-4) M) in hearts whose fast Na+ channels had been inactivated by 25 mM K+. Higher concentrations of cimetidine (10(-3) to 5 X 10(-3) M) increased myocardial cyclic AMP level and allowed the generation of slow APs in such inexcitable tissues. These cimetidine-induced slow APs were not prevented by propranolol (10(-6) to 10(-5) M) or pretreatment with 6-hydroxydopamine (50 mg/kg). These results suggest that cimetidine, in doses higher than that required to block cardiac H2-receptors, may have a cardio-stimulating action mediated through increase of inward Ca++ current.

Action Potentials↗
PubMed1986

Effects of intermittent and continuous haloperidol administration on the dopaminergic system in the rat brain.

The effects of intermittent and continuous treatment with haloperidol (HPD) on dopamine turnover in the rat brain were studied. Each rat was treated with HPD for 14 days by either once daily intraperitoneal injections (2 mg/kg/day) (intermittent HPD group) or continuous infusion by a subcutaneously implanted pump which was adjusted to release 28 mg/kg of HPD over 14 days (continuous HPD group). Seven days after cessation of injections or removal of the pump, the regional changes in DA turnover following an acute dose of HPD (1 mg/kg, intraperitoneally) were examined. The continuous HPD group showed more prominent tolerance to HPD effect of augmenting DA turnover than the intermittent HPD group. It is presumed that continuously administered HPD produces greater tolerance to the acute effect of HPD than intermittently administered HPD.

Animals↗
PubMed1986

[The immunological role of carotenoids in the prevention of cancer].

Epidemiological studies have suggested that the intake of green-yellow vegetables decrease the risk of cancer. Vitamin A, which is abundantly present in green-yellow vegetables in the form of provitamin A, was demonstrated to inhibit chemical and viral-carcinogenesis in experimental animals. However, little is known about the mechanism of anti-carcinogenic effect of vitamin A. Our data seem to support a hypothesis that vitamin A may contribute to the prevention of cancer by augmenting an immunosurveillance system. We found that vitamin A and provitamin A, beta-carotene, enhanced tumor immunity using a syngeneic murine tumor system.

Animals↗
PubMed1986

Optic atrophy, diabetes mellitus and diabetes insipidus.

A 19-year-old Japanese woman developed diabetes mellitus, diabetes insipidus and optic atrophy. Other abnormal ocular findings included color blindness, elevated dark adaptation threshold, loss of oscillatory potentials after a single white flash electroretinogram (ERG), reduced cone response in photopic ERG, and reduced pupillary response to light and convergence. Diabetic retinopathy, which has been thought to be very rare in this syndrome, also was found in the fundi of this patient.

Adult↗
PubMed1986

Extrahepatic portal obstruction in adults--report of an autopsy case.

We report the case of a 31-year-old female with extrahepatic portal vein obstruction. At the age of 16 she had developed hematemesis from esophageal varices. Trans-splenic portography failed to demonstrate the portal trunk, but showed instead well developed collateral circulation. She suffered from repeated hematemesis and ascites despite mesocaval shunt operation and resection of the esophagus for varices. Death resulted from gastrointestinal hemorrhage. Her family history revealed a 30-year-old sister with Takayasu's disease. On autopsy, the portal trunk and the portal vein at the hilus were indistinguishable due to proliferation of hyalinized connective tissue. Cavernous transformation was observed at the hilus. Histologically the presence of the portal trunk and the portal vein was confirmed, but they showed marked sclerosis, and were almost occluded by possible organized thrombus. The cavernous transformation consisted of numerous thin-walled vessels, which were also observed in the medium-sized portal tracts in the liver. The peripheral portal tracts showed no obvious narrowing nor occlusion of the portal vein branches, which are factors usually considered to play an important role in the genesis of portal hypertension in idiopathic portal hypertension. Even though the etiology is not clear, the portal trunk obstruction is concluded to be a significant factor in this case contributing to the development of protracted portal hypertension.

Adult↗
PubMed1986

Biomechanical study of the ligamentous system of the acromioclavicular joint.

The ligamentous structures of the acromioclavicular joint were studied by gross examination and quantitative measurement in twelve human cadaver specimens. Distances between insertions at various extreme positions of the clavicle were studied with the biplane radiographic technique. Ligamentous contributions to joint constraint under displacements were determined by performing load-displacement tests along with sequential sectioning of the ligaments. Twelve modes of joint displacement were examined. The acromioclavicular ligament acted as a primary constraint for posterior displacement of the clavicle and posterior axial rotation. The conoid ligament appeared to be more important than has been previously described. That ligament played a primary role in constraining anterior and superior rotation as well as anterior and superior displacement of the clavicle. The trapezoid ligament contributed less constraint to movement of the clavicle in both the horizontal and the vertical plane except when the clavicle moved in axial compression toward the acromion process. The various contributions of different ligaments to constraint changed not only with the direction of joint displacement but also with the amount of loading and displacement. For many directions of displacement, the acromioclavicular joint contributed a greater amount to constraint at smaller degrees of displacement, while the coracoclavicular ligaments, primarily the conoid ligament, contributed a greater amount of constraint with larger amounts of displacement.

Acromioclavicular Joint↗
PubMed1985

Saponins can cause the agglutination of phospholipid vesicles.

The interaction of saponins with phospholipid vesicles was investigated by means of liposomal agglutination or a precipitation assay. Ginsenoside-Rc, which has an alpha-L-arabinofuranose residue at the non-reducing terminus, exhibited remarkable agglutinability toward egg yolk phosphatidylcholine vesicles, while other saponins lacking this characteristic sugar residue showed less or no agglutinability. The molar ratio of ginsenoside-Rc to egg phosphatidylcholine in the aggregates was estimated to be 0.4-0.5 by a precipitation assay using 14C-labeled egg phosphatidylcholine vesicles. The agglutination was inhibited by p-nitrophenyl alpha-L-arabinofuranoside but not by p-nitrophenyl beta-D-glucopyranoside or arabinogalactan. The results indicated that the alpha-L-arabinofuranose residue in ginsenoside-Rc should be important for the expression of the agglutinability. The agglutinability of ginsenoside-Rc toward lipid vesicles depended on both the polar head groups and fatty acyl chains of phospholipids. Egg yolk phosphatidylcholine vesicles were strongly agglutinated by ginsenoside-Rc, although sphingomyelin, phosphatidylethanolamine, phosphatidic acid and phosphatidylserine were less agglutinated. The agglutinability of ginsenoside-Rc was effective for phosphatidylcholines with short or unsaturated fatty acyl chains. The results suggested that the interaction of ginsenoside-Rc with phospholipid membranes should be affected not only by the chemical structure of the phospholipid but also by the membrane fluidity.

Agglutination↗
PubMed1985

Evaluation of portal circulation in rats by rectal administration of 201Tl followed by intrasplenic injection of 51Cr-labeled microspheres.

The heart-to-liver (H/L) uptake ratio in rats was determined 8 min after the rectal administration of 201Tl. Apart from normal controls, three groups of rats were examined; these were composed of animals with induced (1) acute hepatic damage, (2) liver cirrhosis, and (3) partial portal-vein ligation. After the rectal administration of 201Tl, 51Cr-labeled microspheres were injected into the spleen. The radioactivity of the removed liver, lungs, and heart was determined in a gamma-well scintillation counter, and the radioactivity of 201Tl and the 51Cr-labeled microspheres was separately calculated using simultaneous equations derived from the results of a preliminary experiment. The H/L ratios (201Tl) in the normal controls and the animals with acute hepatic damage were not significantly different; however, there was a positive correlation (P less than 0.01) between the H/L ratio and the shunt index (51Cr microspheres) in three groups, i.e., normal controls, liver cirrhosis, and partial portal-vein ligation.

Animals↗
PubMed1985

Hyperphenylalaninaemia due to impaired dihydrobiopterin biosynthesis: leukocyte function and effect of tetrahydrobiopterin therapy.

We have described the clinical and biochemical status of two patients with tetrahydrobiopterin (BH4) deficiency due to impaired dihydrobiopterin biosynthesis. BH4 administration appeared to improve the mental and psychological status more than did neurotransmitter replacement therapy alone. This enhancement of activities of daily life was seen with a dose of BH4 as low as 1.25 mg kg-1 day-1. Granulocyte adherence capacity was below normal and recovered after BH4 therapy in both patients. B-cell differentiation capacity was altered either before or after therapy.

Amino Acid Metabolism, Inborn Errors↗
PubMed1985

Wasp venom peptides; wasp kinins, new cytotrophic peptide families and their physico-chemical properties.

In addition to wasp kinins, the wasp venom contains a series of hydrophobic peptides, mastoparans and chemotactic peptides as major peptidergic components. The first major component in the venom is mastoparam. The peptides in the mastoparan family are tetradecapeptide amides which cause degranulation of the mast cells to release histamine from the cells, and act on the adrenal chromaffin cells to release catecholamines and adenylic acids. Some mastoparans cause hemolysis and serotonin release from the platelets. The new cytotrophic peptides as the second major components are tridecapeptide amides possessing chemotactic activity for polymorphonuclear leucocytes and monocytes. Some of the peptides in this family also cause histamine release from the mast cells. Mastoparan takes a random coil structure in aqueous solution but changes its conformation to alpha-helix in methanolic solution or in the presence of lysophosphatidyl choline. This fact is confirmed also by the transferred nuclear overhauser effect by NMR analysis. The similar phenomenon was observed in the family of chemotactic peptides. The helical conformation of these peptides are amphipathic structure in which all of side chains of the hydrophobic amino acids are located on one side of the axis, and those of the basic or the hydrophilic amino acid residues are on an opposite side. Mastoparan enhances the membrane conductivity of the lipid bilayer when the peptide is investigated by the black lipid membrane experiment. This indicates that the peptide may be assembled in the membrane by changing its conformation and, for some reason, enhances the ion transfer through the membrane. These properties of the peptide may reveal various activities on the cell membrane.

Animals↗
PubMed1985

Short latency somatosensory evoked potentials to peroneal nerve stimulation in normal Japanese children.

Short latency somatosensory evoked potentials (SSEP) were elicited by stimulation of the peroneal nerve in 68 normal children of 39 weeks to 15 years old. In all subjects, three positive potentials (P1, P2 and P3) and one negative potential (N1) were consistently recorded. A further positive potential (P4) after N1 was not always observed. There was no change of wave form with development. P1, P2, P3 and N1 might be generated in subcortical structures; caudal cervical spine, brainstem, thalamus and thalamocortical pathway, respectively. The latency of each peak per one meter body length decreased with age until 5 or 6 years of age. Moreover, the latency between peaks per one meter body length also decreased with age until 5 to 6 years of age. These findings are consistent with the development of SSEP on median nerve stimulation and with the developmental phenomenon of spinal conduction velocity, and might be related to the increase in the diameter and the progressive myelination of nerve fibers.

Adolescent↗