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Biomedical subjects

K Fujimoto

Publications and source records attributed to K Fujimoto.

At least 685 records · Page 38Linked to original sources
PubMed1990

[Improvement in the mechanical properties of artificial blood vessel suitable for the extracranial cerebral artery].

Saphenous vein interposition grafts have been commonly used for the reconstruction of occlusive lesions in the extracranial cerebral vessels, such as carotid or vertebral arteries. In contrast, cerebral revascularization using an artificial blood vessel has not been so common. This is due to the fact that conventional artificial blood vessels have been too firm or too rigid for use in the neurosurgery. Another reason is that the long term patency rate of small caliber artificial blood vessels has usually been inferior to that found in autologous vein grafts. The purpose of this study was to develop a soft and compliant artificial blood vessel suitable for cerebrovascular surgery. This new artificial blood vessel is made of polyurethane, porous in structure (porous polyurethane). Thus, multiple small-sized pores exist both in the inner and outer surfaces, and in the wall of the porous polyurethane graft. To test its mechanical properties, we evaluated stress-strain curves and compliance. In comparison to expanded polytetrafluoroethylene graft (Goretex), which has been one of the most commonly used artificial blood vessels in the cardiovascular surgery, the mechanical properties of the porous polyurethane graft more closely resembled those of the common carotid artery in dogs. Thus, porous polyurethane graft was shown to be a soft and compliant new artificial blood vessel. This means not only that it can be maneuvered with technical ease for anastomosis but also that there is a reduction of compliance-mismatch between the host vessel and the artificial vessel. Compliance mismatch has been documented as a major factor in the inducement of intimal hyperplasia, which causes a delayed occlusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Measurement of K vitamins in animal tissues by high-performance liquid chromatography with fluorimetric detection.

A highly sensitive method for measuring endogenous phylloquinone and menaquinones in animal tissues was developed, based on high-performance liquid chromatography with coulometric reduction and fluorimetric detection, following extraction from tissue homogenate and purification on a Sep-Pak silica cartridge followed by thin-layer chromatography. The detection limits of phylloquinone, menaquinone-4, -6, -10 and -13 were 40, 40, 50, 70 and 80 pg/g in rat liver, respectively.

Animals↗
PubMed1989

Extraneuronal localization of acetylcholine and its release upon nicotinic stimulation in rabbits.

A study was undertaken to examine the origin of plasma acetylcholine (ACh). The ACh content of blood cells was about 25 times higher than that of plasma in normal rabbits (3,722 vs 140 pg/ml blood, n = 7). Plasma ACh content in rabbits having antibody against ACh was about 80 times higher than in normal rabbits, while no difference was observed in the ACh content of blood cells between the groups. Nicotine (100 micrograms/kg, i.v.) produced a significant increase in plasma ACh content and a decrease in the ACh content of blood cells in normal rabbits. These data demonstrate that a large amount of ACh is localized in blood cells and that a considerable proportion of plasma ACh originates from blood cells, suggesting that ACh acts not only as a neurotransmitter but also as an autacoid.

Acetylcholine↗
PubMed1989

The effect of dietary autoxidized oils on immunocompetent cells in mice.

Effects of dietary autoxidized oil on immunocompetent cells, such as splenocytes and thymocytes, were studied in mice. When the autoxidized methyl linoleate was administered orally to male C57BL/6 mice in a single dose, the DNA synthesis of thymocytes was remarkably depressed 1 day after the treatment, and then the mitogenic response to concanavalin A of splenocytes was increased 3 days after the dose. With long-term (90 days) feeding of slightly autoxidized soybean oil (with a peroxide value of 150 mequiv/kg) in mice, the DNA synthesis of thymocytes was depressed and the mitogenic response to concanavalin A of splenocytes was increased. No effect was observed on plasma glutamic acid-oxaloacetic acid transaminase and glutamic acid-pyruvic acid transaminase levels, nor on liver thiobarbituric acid reactants due to the dose of autoxidized soybean oil. These findings indicate that oral intake of autoxidized oil affects immunocompetent cells and causes depression of the DNA synthesis of thymocytes in mice.

Animals↗
PubMed1989

Hypothalamic sites of neuronal histamine action on food intake by rats.

To identify sites of histaminergic modulation of food intake, histamine H1-receptor antagonist was microinfused into the rat hypothalamus, the ventromedial hypothalamus (VMH), the lateral hypothalamus (LHA), the paraventricular nucleus (PVN), the dorsomedial hypothalamus (DMH), or the preoptic anterior hypothalamus (POAH), during the early light period. Feeding, but not drinking, was elicited in 100% of the rats (P less than 0.01) that were bilaterally microinfused with 26 nmol chlorpheniramine into the VMH. Unilateral infusion into the VMH did not affect food intake at doses of 26 or 52 nmol. Feeding was also induced by bilateral microinfusion into the PVN, but only the 52 nmol dose was effective. Bilateral infusions into the LHA, the DMH or the POAH did not affect ingestive behavior. Feeding induced by an H1-antagonist was completely abolished in all 7 rats tested when endogenous neuronal histamine was decreased by pretreatment with alpha-fluoromethylhistidine (100 mg/kg). The findings suggest that H1-receptors in the VMH and the PVN, but not in the LHA, the DMH or the POAH, may be involved in histaminergic suppression of food intake.

Animals↗
PubMed1989

Mutations in the cytoplasmic domain of the 275 kd mannose 6-phosphate receptor differentially alter lysosomal enzyme sorting and endocytosis.

The cation-independent mannose 6-phosphate receptor (Cl-MPR) sorts newly synthesized lysosomal enzymes in the Golgi and endocytoses extracellular lysosomal enzymes. To determine the role of the 163 amino acid cytoplasmic domain of the Cl-MPR in these functions, receptor-deficient mouse L cells were transfected with normal bovine Cl-MPR cDNA or cDNAs mutated in the cytoplasmic domain. The normal Cl-MPR functioned in sorting and endocytosis. Mutant receptors with 40 and 89 residues deleted from the carboxyl terminus of the cytoplasmic tail functioned normally in endocytosis, but were partially impaired in sorting. Mutant receptors with larger deletions leaving only 7 and 20 residues of the cytoplasmic tail were defective in endocytosis and sorting. A mutant receptor containing alanine instead of tyrosine residues at positions 24 and 26 was defective in endocytosis, and partially impaired in sorting. Receptors deficient in endocytosis accumulated at the cell surface. These results indicate that the cytoplasmic domain of the Cl-MPR contains different signals for rapid endocytosis and efficient lysosomal enzyme sorting.

Amino Acid Sequence↗
PubMed1989

Sex-linked differences in susceptibility of cynomolgus monkeys to type II collagen-induced arthritis. Evidence that epitope-specific immune suppression is involved in the regulation of type II collagen autoantibody formation.

To determine whether sex-linked factors are important in the susceptibility and resistance of cynomolgus monkeys to type II collagen-induced arthritis, we immunized 5 males and 10 females with chick type II collagen (CII) and studied their clinical and immune responses. All 10 females developed overt arthritis and produced antibodies to CII and cross-reactive antibodies to monkey type II collagen (MkII). In contrast, only 1 male monkey developed arthritis, which was transient and mild in severity. Examination of antisera obtained from the male monkeys disclosed high titers of antibody to CII, but little antibody to MkII. The cyanogen bromide peptide recognition patterns varied markedly from animal to animal, implying that monkeys are capable of recognizing multiple arthritogenic determinants on CII.

Animals↗
PubMed1989

Attenuation of anorexia induced by heat or surgery during sustained administration of ginsenoside Rg1 into rat third ventricle.

Effects of ginsenoside Rg1 (Rg1), a major component of panax ginseng, on modulation of ingestive behavior were investigated. No direct effect was observed on food intake after 10 microliters infusion of 1.0, 2.0, 4.0 or 8.0 mM Rg1 into the rat third ventricle for 10 min. Continuous osmotic infusion of 4.0 mM Rg1 at a rate of 0.966 microliter/h into the third ventricle prevented feeding suppression caused by surgical procedure to implant an osmotic minipump. Continuous infusion of Rg1 attenuated anorexia, increased water intake, and decreased ambulation, that were produced by elevation of environmental temperature from 21 degrees C to 30 degrees C. Consequently, rats maintained body weight and rectal temperature unchanged. The results indicate that sustained central administration of Rg1 may relieve anorexia caused by implantation surgery or by a heated environment.

Animals↗
PubMed1989

Dry heat popping of amaranth seed might damage some of its essential amino acids.

Amaranth was a major crop among the Aztecs. In Mexico the seed is popped and eaten with brown sugar. The crude protein content of the seed is 14 +/- 2% but its contents of lysine and tryptophan are 6.2 and 1.6 g/16 g N respectively. We developed a popping method based on a fluid bed system (FBS) whereas the traditional method (TM) is just to pop the seeds manually in a hot plate. Assays carried out were evaluation of racemization of the amaranth protein due to heat treatment, amino acid composition of the raw and heat treated seeds and a biological experiment testing whether leucine was the most limiting amino acid of amaranth protein. Male rats were fed both popped amaranths and roasted amaranth. Parboiled amaranth and casein were controls. The results were: (a) Lys, Arg and Cys were damaged in the heat treated seeds; (b) Asp, Met, Glu, Ala and Phe were racemized in that decreasing order in the seeds popped and roasted by the TM; (c) the estimated net protein retention (NPR) and estimated net protein utilization (NPU) of popped amaranths by either method were not different, but were lower than for the parboiled amaranth. The parboiled amaranth was not different from casein; (d) Leu was not the most limiting amino acid in any of the amaranth seeds tested. After Lys, sulfur amino acids appear to be the next most limiting in severely heat treated amaranth. The FBS seems to be a promising method for popping amaranth at industrial level.

Amino Acids, Essential↗
PubMed1989

Structural evaluation of glucose analogues on feeding elicitation in rat.

The effects of 12-mumol doses of the glucose analogues glucosamine, 2-fluoroglucose, 2-chloroglucose, 2-deoxyglucose (which were modified at carbon 2 of the glucopyranose ring), 1-aminoglucose and 1-deoxyglucose (modified at carbon 1), on feeding behavior and plasma glucose, insulin, and glycerol were examined after infusion into the rat third cerebroventricle. Plasma glucose and glycerol levels were elevated by glucosamine or 1-aminoglucose. Plasma insulin levels were unchanged by these analogues. Feeding was induced in 62% to 87% of the rats tested after infusion of glucosamine, 2-fluoroglucose, 2-chloroglucose, 2-deoxyglucose, 1-aminoglucose, or 1-deoxyglucose (mean meal size in responding rats, 43.9, 25.8, 22.7, 16.0, 42.3, and 3.8 pellets, respectively). The order of potency to induce feeding was amino, halogen, and hydrogen groups. These data reinforced the concept that the potency of glucose analogues to induce feeding depends on substituents at carbon 1 and carbon 2 of the glucopyranose ring.

Animals↗
PubMed1989

Characteristics of psychomotor performance and time cognition in moderately obese patients.

To clarify adherence of obese subjects to external food-relevant stimuli, we examined time cognition and psychomotor functioning of the obese under noneating conditions in the present study. Matched on the basis of age, sex, height, intelligence quotient and education, 13 moderately, but adult-onset obese (mean obesity index +/- SEM, 53.9 +/- 5.0% by Matsuki's method) and 13 normal weight subjects (-6.3 +/- 2.3%) were tested. Obese females were slower than normal weight control subjects in alternate tapping of two metal plates (p less than 0.01) and in transfer of a dowel (p less than 0.05). Normal subjects were slightly but significantly (p less than 0.05) more efficient in a self-cued traverse movement test, whereas the obese subjects were very much less efficient in the self-cued than in the externally-cued test. These findings suggest that evaluation of deficits of the obese must consider other factors in addition to simple physical slowness due to fattening. In time cognition tests, cognitive levels of the obese were more accurate when initiated by time cues than when they were self-cued (p less than 0.01). The results indicate that obese (even after adult-onset) may exhibit impairment in internal time cognition when deprived of external modulating time cues.

Adult↗
PubMed1989

Impaired hypophagia induced by fecal anorexigenic substance in Zucker obese rats.

Influence of fecal anorexigenic substance (FS-T) on feeding by Zucker obese rats was compared to that by their lean littermates and Wistar King A rats. FS-T, which has been found to suppress food intake mainly by activation of glucoreceptor neurons in the ventromedial hypothalamus, was injected intraperitoneally in a dose of 7 U/kg at 1930 hr, immediately before the dark period. Potency of FS-T in feeding suppression was much less in the obese rats than in their lean littermates or the Wistar King A rats. Meal size of the obese rats was decreased after the injection, but meal duration was unaffected. The suppressive effect on the lean rats and the Wistar King A rats included decrease of both size and duration of the meal. These results suggest that chemosensitivity in the ventromedial hypothalamus of Zucker obese rats may be impaired, which may be one explanation of the obesity in Zucker obese rats.

Animals↗
PubMed1989

Impairment of active avoidance produced after destruction of pedunculopontine nucleus areas in the rat.

Pedunculopontine nucleus areas were lesioned bilaterally in the rat by local injection of kainic acid. When rats so treated were tested for active avoidance behavior in shuttle boxes we found that their avoidance acquisition was completely abolished, whereas their intertrial locomotor activity and escape behavior were not affected. In the lesioned rats, choline acetyltransferase activity in the medial thalamus and substantia nigra decreased, but not in the lateral thalamus, hippocampus, or cerebral cortex. These findings suggest that the cholinergic pedunculopontine-medial thalamus projection plays an important role in memory acquisition in the rat.

Animals↗
PubMed1989

Reduction in blood pressure and vascular reactivities to pressor substances by chronic treatment with piretanide in spontaneously hypertensive rats.

1. Effects of treatment with piretanide (10 and 30 mg/kg per day p.o.) for 9 weeks on blood pressure, urinary excretion of electrolytes, and vascular reactivities to pressor substances were investigated in 10-week-old spontaneously hypertensive (SHR) rats. 2. Piretanide (30 mg/kg) prevented development of hypertension and produced a significant reduction in blood pressure from the 2nd week of the treatment. A slight decrease in blood pressure was observed in rats treated with the lower dose of piretanide. 3. Piretanide produced significant and dose-dependent diuresis throughout the experiment. Although significant natriuresis was observed in the 1st and 4th week of the treatment, natriuresis disappeared in the 8th week. Urinary excretion of potassium was decreased significantly by piretanide throughout the experiment. 4. Attenuation of pressor responses to phenylephrine and angiotensin II was observed after chronic administration of piretanide (30 mg/kg). 5. These data demonstrate the contribution of attenuated vascular reactivities to pressor substances as well as a diuretic action to the antihypertensive effect of piretanide during its long-term administration in SHR rats.

Angiotensin II↗
PubMed1989

Effects of TRH and DN-1417 on high potassium-evoked acetylcholine release from rat basal forebrain slices determined directly by radioimmunoassay.

1. High potassium (50 mM)-evoked acetylcholine (ACh) release from rat basal forebrain slices under conditions without an exogenous choline supply was determined using a radioimmunoassay for ACh. 2. A consistent amount of ACh release was observed at each repetitive stimulation and ACh content in brain slices was not altered by potassium stimulations. These results indicate the existence of a large intracellular releasable ACh store, which is independent of new synthesis from exogenous choline. 3. Atropine, even at a concentration of 10(-6) M, did not affect the potassium-evoked ACh release. Thus, modulation of ACh release by the muscarinic autoreceptor was not revealed under the conditions employed. 4. Thyrotropin-releasing hormone (TRH, 10(-4) M) caused a slight and statistically insignificant increase in potassium-evoked ACh release. DN-1417, a TRH analogue, at a concentration of 10(-4) M significantly increased potassium-evoked ACh release. These findings indicate that DN-1417 is able to enhance ACh output independently of ACh synthesis from exogenous choline.

Acetylcholine↗
PubMed1989

Possible active components of tan-shen (Salvia miltiorrhiza) for protection of the myocardium against ischemia-induced derangements.

Extract of Tan-Shen (Salvia miltiorrhiza, Labiatae), a Chinese traditional crude drug, was reported to show beneficial activity for heart disease. Chemical examination on the extract was performed on the basis of screening for protective action on the ischemic myocardium. Isolated hearts were subjected to hypoxic perfusion for 20 min, followed by 45 min reoxygenation, and the recovery of cardiac contractile force and changes in UV absorbance of the perfusate were examined. Among the components isolated, tanshinone I, cryptotanshinone, and tanshinone VI elicited a significant enhanced recovery of the contractile force upon reoxygenation. This was associated with a decrease in the increase in UV absorbance of the perfusate, suggesting the preservation of ATP metabolites in the myocardium. This, in turn, may enhance the restoration of ATP upon oxygen-replenishment. The results suggest that tanshinone I, cryptotanshinone, and tanshinone VI can protect the myocardium against ischemia-induced derangements.

Animals↗
PubMed1989

Reexamination of 123I-IMP-SPECT at interictal stages in adult partial epilepsy.

123I-IMP-SPECT scans at the interictal stages in 13 epileptic patients with normal X-ray CT findings were reexamined at intervals of 1.9 +/- 0.8 years. Interictal scalp EEGs were recorded a few hours after each SPECT scan. All of the SPECT abnormalities indicated focal hypofixation images of 123I-IMP, i.e. zones of a decreased rCBF reflecting a functional inactivation. Among 11 patients with the SPECT abnormalities in the first SPECTs, eight cases had the complete or partial regional reproduction of the abnormalities in the second SPECTs. As changes in the SPECT findings, an alteration from the abnormal SPECT images to normal images (normalization), the reverse change, the enlargement and reduction of hypofixation sites were seen. Also the EEG foci had various changes (right and left regional changes, etc.). Because of these SPECT and EEG changes, the regional relationship between the SPECT abnormalities and EEG foci altered in 7 patients (a change from disagreement to agreement, etc.). The high reproduction rate of SPECT abnormalities appears to increase the reliability or utility of SPECT scans for a regional diagnosis of epileptic foci. The present SPECT changes, especially the normalization or the severse change, suggest that the interictal epileptic focus may have a functional fluctuation. In addition, the causes of regional disagreement between the SPECT abnormalities and EEG foci were discussed on the basis of the present SPECT and EEG changes.

Adult↗