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Biomedical subjects

R Matsuo

Publications and source records attributed to R Matsuo.

At least 73 records · Page 4Linked to original sources
PubMed1992

Synthesis and nonthrombogenicity of polymer membrane with surface-graft polymers carrying thrombin inhibitor.

An acrylamide derivative of a thrombin inhibitor was synthesized and graft polymerized to the surfaces of polymer membranes. The thrombin-inhibitor activity was unaffected by the introduction of an acryloyl group. The surface-graft membrane deactivated thrombin markedly and suppressed adhesion of platelets, resulting in a high nonthrombogenicity. Immersion of polymer membranes blended with the thrombin inhibitor in phosphate-buffered saline for 10 d resulted in the loss of nonthrombogenicity, while the polymer membranes grafted with the thrombin inhibitor derivative maintained the nonthrombogenicity over a long period.

Acrylamides↗
PubMed1992

The role of Kupffer cells in complement activation in D-Galactosamine/lipopolysaccharide-induced hepatic injury of rats.

To investigate the role of Kupffer cells in complement activation, we used a rat model of acute hepatic injury induced by D-Galactosamine (GalN) and lipopolysaccharide (LPS). In in vivo study, minimal histological changes were observed after i.p. GalN (200 mg/kg) single administration. Complement hemolytic activity (CH 50) decreased to 70% of its initial value 2-3 h after i.p. LPS (1.5 mg/kg) single administration. Massive hepatic necrosis was induced by simultaneous administration of GalN and LPS. After 2-3 h, CH 50 decreased to 70% of its initial value, and deposition of C3 fluorescence (C3) was observed in Kupffer cells. After 4 h, GPT was greatly increased (1286 +/- 240 IU/l), CH 50 was further reduced, and C3 was observed on hepatocyte membranes and in the cytosol. In in vitro study, we used hepatocyte cultures and co-cultures of hepatocytes and Kupffer cells to investigate the participation of GalN, LPS, complement, and Kupffer cells in hepatic cell necrosis. We found no increase of LDH (% leakage) when LPS and complement were added to the medium (22.7 +/- 5.7%). A moderate increase was observed with the addition of GalN (33.2 +/- 2.6%). A remarkable increase was observed only with the addition of GalN, LPS, and complement to the co-culture (50.0 +/- 8.8%). These results suggest that Kupffer cells activated by LPS are very important in promoting acute hepatic injury by complement.

Alanine Transaminase↗
PubMed1992

Clinical evaluation of interventional radiology for renal cell carcinoma in 100 patients.

One hundred of 160 patients with renal cell carcinoma (RCC) were treated by interventional radiology (IVR) in the period from 1978 to 1989. The number and kind of interventions done each year were classified retrospectively. More than half of the patients underwent therapeutic arterial embolization or intraarterial infusion of anticancer drugs during the first half of the period. More recently, about half of the patients have had nephrectomies without IVR. One patient with advanced RCC by IVR 18 times lived 8 years and three months after diagnosis, but that was exceptionally long. IVR has been more effective against hepatocellular carcinoma than RCC, for several reasons.

Angiography↗
PubMed1991

Multiloculated renal cell carcinoma.

Multiloculated renal cell carcinoma and multilocular renal cyst with renal cell carcinoma are uncommon diseases. We report on 2 cases of multiloculated renal cell carcinoma. To our knowledge 16 cases of multiloculated renal cell carcinoma and multilocular renal cyst with renal cell carcinoma have been previously described in detail. The authors review the literature and discuss the aetiology and diagnosis of the disease.

Carcinoma, Renal Cell↗
PubMed1991

Electrophysiological and behavioral studies on the taste of umami substances in the rat.

Electrophysiological and behavioral experiments were performed to reveal taste properties of "umami" substances such as monosodium glutamate (MSG) and disodium inosine monophosphate (IMP) in rats. To eliminate the taste effects of Na ions contained in these umami substances, we dissolved them in 0.01 mM amiloride, which is known to block sodium responses. In the electrophysiological study, taste responses of the whole chorda tympani nerve were recorded. The magnitude of responses to MSG (or IMP) at concentrations below 0.1 M (or 0.01 M) was less than 10% of that to 0.1 M NaCl. On the other hand, the mixtures of MSG and IMP showed responses 2-7 times larger than the arithmetric sum of the responses to each component of the mixtures. A new sweet taste inhibitor (Gymnema sylvestre extract) strongly suppressed neural responses to mixtures of MSG and IMP as well as sucrose, but only weakly or negligibly to individual solutions of these umami substances. In the behavioral study, the brief exposure two-bottle preference test and conditioned taste aversion paradigm were used. MSG was most preferred at 0.3 M (preference ratio = 57%), IMP, at 0.01 M (61%), and both were less preferred or rejected at higher concentrations. In contrast, mixtures of MSG and IMP were more preferred at a broad concentration range (e.g., 82% for 0.1 M MSG + 0.01 M IMP). Aversive conditioning to umami substances was generalized to sucrose, and vice versa, but not to 0.1 M NaCl, 0.01 M HCl, and 0.1 mM quinine hydrochloride.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Aversive taste stimuli increase CGRP levels in the gustatory insular cortex of the rat.

Calcitonin gene-related peptide-like immunoreactivity (CGRP-IR) was surveyed immunohistochemically in the insular cortex of the rat, and the levels of insular cortical CGRP-IR were measured with the radioimmunoassay method following intraoral stimulation with various taste stimuli. CGRP-IR was localized in nerve fibers within the agranular and dysgranular insular cortices. The CGRP-IR levels in the rostral (gustatory) part of the insular cortex were increased significantly by strongly aversive taste stimuli such as quinine hydrochloride and conditioned taste stimuli (NaCl and sucrose) which animals had been taught to avoid. The results suggest that CGRP in the gustatory insular cortex is concerned with rejection or avoidance behaviors to aversive taste stimuli.

Animals↗
PubMed1990

Taste nerve responses during licking behavior in rats: importance of saliva in responses to sweeteners.

Taste responses of the rat chorda tympani nerve, innervating taste cells on the anterior part of the tongue, were recorded under awake and anesthetic conditions. Responses to licking of taste solutions in conscious animals were compared with those to taste solutions poured onto the tongue, without contamination of saliva, in anesthetized ones. The most noticeable finding was that sweet-tasting substances such as sugars and amino acids elicited larger magnitudes of neural responses (2-4 times) under awake condition than under anesthetic experimental condition. We conclude that a proper ionic composition of mucous substances covering the surface of the taste cell membrane is important in generating good responses to sweeteners as observed in licking rats.

Action Potentials↗
PubMed1990

REM sleep without muscle atonia (stage 1-REM) and its relation to delirious behavior during sleep in patients with degenerative diseases involving the brain stem.

Nocturnal sleep was examined in 12 patients with degenerative diseases involving the brain stem and in 2 patients with late cerebellar cortical atrophy (LCCA). A peculiar sleep state, characterized by the concomitant appearance of a low-voltage mixed frequency EEG, rapid eye movements (REMs) and tonic EMG in mental muscles, repeatedly appeared during nocturnal sleep in all of the 12 patients with degenerative diseases involving the brain stem and it was called stage 1-REM after Tachibana et al. In 8 of the 12 patients, delirious or oneiric behavior appeared during, or soon after, the episodes of stage 1-REM. Inner experiences reported by one of the subjects well corresponded to his behavior during the episode of stage 1-REM. Stage 1-REM was not observed during nocturnal sleep of the patients with LCCA. These results indicate that a degenerative lesion in the brain stem induced stage 1-REM and delirious behavior during nocturnal sleep through abolishing muscle atonia of REM sleep and causing dissociation of the functional components characterizing REM sleep.

Aged↗
PubMed1989

Response properties of lateral hypothalamic neurons during ingestive behavior with special reference to licking of various taste solutions.

Activity of 58 single neurons in the lateral hypothalamic area (LHA) was recorded while Wistar male rats were drinking water and various taste solutions in a test box. A cue tone was presented before opening of a shutter for access to a drinking spout. Except 8 neurons which were non-responsive in the present experimental paradigm, 50 neurons were classified into 3 types according to their response properties: (1) 10 neurons changed their activity with arousal state or circadian rhythm, (2) 10 neurons responded to specific sensory stimuli, i.e. 2 were classified as taste-responsive neurons, which responded excitatory to sodium salts, 3 neurons responded to olfactory stimulation, 5 to somatosensory stimulation applied to the perioral region, and (3) the remaining 30 decreased their activity during licking of liquids regardless of their qualities. Besides this classification, activity of 28 of 58 LHA neurons was altered after onset of the cue tone (or before start of licking), i.e. 24 increased their activity (learned anticipatory response), and 3 modulated their tonic activity into burst discharges corresponding to sniffing, and 1 increased its activity in relation to stepping toward the drinking spout. These data suggest that about half of the LHA neurons increased their activity in anticipatory (searching or approaching) periods just before ingestion, and decreased activity in rewarding periods during ingestion of water or sapid solutions.

Action Potentials↗
PubMed1989

Sensory and motor responses of trigeminal and reticular neurons during ingestive behavior in rats.

Activities of 53 neurons in the brain stem were recorded with chronically implanted fine wires in freely eating and drinking rats. Twenty units were isolated from the trigeminal mesencephalic nucleus; 18 were spindle afferents and 2 periodontal afferents. The spindle units were classified into 4 types: 5 units showed rhythmical activity related only to the jaw opening phase during both licking and chewing, 8 units discharged at jaw opening phase during licking, but both at jaw opening and jaw closing phases during eating, 2 units increased phasic activity at jaw opening phase during licking, but increased tonically independent of jaw movements during eating, and the remaining 3 units responded only at jaw closing phase both in licking and eating behavior. Nine units were assumed to be alpha motoneurons isolated from the trigeminal motor nucleus; 2 innervating the temporalis muscle, 3 the masseter muscle, 2 the digastric muscle, and the remaining 2 presumably the pterygoid muscles. These units, with a mean tonic spontaneous rate of about 10 impulses/s, showed phase-related rhythmical burst activities during licking and eating. Four units were isolated from the trigeminal main sensory nucleus. Sixteen units were isolated from the medullary reticular formation and 1 from the pontine reticular formation. Of these 16 units, 3 from the parvocellular part of the medullary reticular formation were presumably premotor interneurons, and 3 units in the "intertrigeminal region", 2 units in the "juxtatrigeminal region", and 8 units in the "supratrigeminal region" were responsive to multiple sensory modalities. These results demonstrate that almost all the units sampled showed characteristic rhythmic activities associated with the position of the tongue or mandible during rhythmical jaw movements.

Action Potentials↗
PubMed1989

Gustatory-salivary reflex: neural activity of sympathetic and parasympathetic fibers innervating the submandibular gland of the hamster.

Electrophysiological experiments were performed to clarify the neural control mechanisms subserving gustatory-salivary reflex in anesthetized and decerebrate hamsters. Efferent neural activities of postganglionic sympathetic and preganglionic parasympathetic fibers, innervating the submandibular gland, were recorded when taste stimuli were infused into the oral cavity. Neural activities of primary gustatory afferents were also recorded from the chorda tympani (innervating the anterior part of the tongue) and the glossopharyngeal nerve (innervating the posterior part of the tongue). The parasympathetic fibers showed a low rate of spontaneous discharges (about 0.3 Hz), and responded tonically in an excitatory manner to taste stimulation. The magnitude of parasympathetic activity was highly correlated with the magnitude of gustatory afferent responses of the chorda tympani rather than that of the glossopharyngeal nerve. On the other hand, the sympathetic fibers showed irregular burst discharges (1.5 burst/s), and the rate of burst discharges was increased in response to high concentrations of HCl (0.03 M) or NaCl (1 M) solutions. Deafferentation experiments suggest that the parasympathetic activity is mainly influenced by gustatory information via the chorda tympani, while the sympathetic activity can be evoked by both the chorda tympani and glossopharyngeal nerve.

Action Potentials↗
PubMed1989

Taste responses of cortical neurons in freely ingesting rats.

1. Activities of 35 taste-responsive neurons in the cortical gustatory area were recorded with chronically implanted fine wires in freely ingesting Wistar rats. Quantitative analyses were performed on responses to distilled water, food solution, and four taste stimuli: sucrose, NaCl, HCl, and quinine hydrochloride. 2. Taste-responsive neurons were classified into type-1 and type-2 groups according to the response patterns to licking of the six taste stimuli. Type-1 neurons (n = 29) responded in excitatory or inhibitory directions to one or more of the taste stimuli. Type-2 neurons (n = 6) showed responses in different directions depending upon palatability of the liquids to rats: neurons showing excitatory (or inhibitory) responses to palatable stimuli exhibited inhibitory (or excitatory) responses to unpalatable stimuli. 3. Correlation coefficients of responses to pairs of stimuli across neurons suggested that palatable stimuli (water, food solution, sucrose, and NaCl) and unpalatable stimuli (HCl and quinine) elicited reciprocal (excitatory vs. inhibitory) responses in type-2 neurons, whereas type-1 neurons showed positively correlated responses to specific combinations of stimuli such as food solution and NaCl, sucrose and HCl, NaCl and quinine, and HCl and quinine. 4. A tendency toward equalization of effectiveness in eliciting responses among the four basic taste stimuli was detected on the cortex. The ratios of mean evoked responses in 29 type-1 neurons in comparison with spontaneous rate (4.4 spikes/s) were 1.7, 1.9, 1.8, and 1.9 for sucrose, NaCl, HCl, and quinine, respectively. 5. The breadth of responsiveness to the four basic taste stimuli was quantified by means of the entropy measure introduced by Smith and Travers (33). The mean entropy value was 0.540 for 29 type-1 neurons, which was similar to 0.588 previously reported for rat chorda tympani fibers, suggesting that breadth of tuning is not more narrowly tuned in a higher level of the gustatory system in the rat. 6. Convergent inputs of other sensory modalities were detected exclusively in type-1 neurons. Thirteen (45%) of 29 type-1 neurons also responded to cold and/or warm water, but none of 6 type-2 neurons responded to thermal stimuli. Two (7%) of 29 type-1 neurons responded to almond and acetic acid odors, but the 6 type-2 neurons did not. Two (13%) of 16 type-1 neurons responded to interperitoneal injection of LiCl, which is known to induce gastrointestinal disorders, with a latency of approximately 5 min, but 4 type-2 neurons tested were not responsive to this stimulation.(ABSTRACT TRUNCATED AT 400 WORDS)

Action Potentials↗
PubMed1989

Neural substrates for reflex salivation induced by taste, mechanical, and thermal stimulation of the oral region in decerebrate rats.

In order to investigate the neural mechanisms of reflex salivary secretion, experiments were carried out on anesthetized, decerebrate rats from which the volumes of submandibular salivary secretion and the efferent discharges in the preganglionic parasymapathetic fibers innervating the submandibular gland were recorded. Salivary secretion was induced by either infusing a taste solution, or an aliquot of hot water (45-55 degrees C) into the oral cavity, or by pinching the frontal parts of the oral region with a pair of forceps. The reflex salivation induced by noxious thermal and mechanical stimuli was markedly reduced by lesioning either the caudal (VC), or the interpolar (VI) trigeminal sensory nuclei. Taste-elicited salivary secretion was significantly reduced by lesioning the nucleus of the tractus solitarius (NTS). Of 43 preganglionic parasympathetic fibers sampled, 27 responded to both noxious mechanical and thermal stimulation of the oral region, and to electrical stimulation of the VC. Ten fibers responded only to taste stimulation and to electrical stimulation of the NTS. The remaining 6 fibers responded to both taste and noxious thermal stimulation of the oral region. These fibers responded well to NTS stimulation, but gave only a slight response to VC stimulation. These results suggest that two distinct neural pathways exist which mediate reflex salivation in the lower brain stem of the rat, i.e., the taste pathway via the NTS and the nociceptive pathway via the trigeminal sensory nuclei.

Animals↗
PubMed1989

Two cases of venous aneurysm of the intrahepatic portal vein branch: MR demonstration.

Two cases are reported of congenital intrahepatic portal vein aneurysm in women who had chronic hepatitis. Ultrasound (US) and computed tomography (CT) investigations revealed vascular communication between intrahepatic portal vein and venous aneurysms in both cases. These portal vein aneurysms were fusiform in shape and two and one centimeter in diameter in each case. On angiography portal-hepatic venous shunt was observed in one case. The MR image of two cases were presented. We believe this is the first report of MR image of portal vein aneurysm.

Aged↗
PubMed1988

Taste effects of 'umami' substances in hamsters as studied by electrophysiological and conditioned taste aversion techniques.

Behavioral and electrophysiological experiments were performed to examine whether or not the taste of 'umami' substances such as monosodium glutamate (MSG), disodium 5'-inosinate (IMP), and disodium 5'-guanilate (GMP) is really unique in hamsters. When the animals were conditioned to avoid ingestion of MSG (or IMP) or their mixture by pairing its ingestion with an i.p. injection of LiCl, suppression of drinking generalized to IMP (or MSG), GMP, NaCl, and other sodium salts. Suppression of drinking after conditioning to NaCl generalized to MSG, IMP, GMP, and inorganic sodium salts. These learned aversions to umami substances and sodium salts were abolished by bilateral deafferentation of the chorda tympani, but were not affected by destruction of the bilateral glossopharyngeal nerves. The integrated whole-nerve responses of the chorda tympani to MSG, IMP, and NaCl were similar to each other, consisting of the initial dynamic phase and the following tonic phase. Synergism of chorda tympani responses to a mixture of MSG and IMP was not observed. Across-fiber response patterns of the chorda tympani for MSG, IMP, or their mixture were very similar to that for NaCl. Even the high concentrations of umami substances (0.3 M MSG, 0.3 M IMP, and the mixture) did not elicit any detectable responses in the glossopharyngeal nerve. These results suggest that the taste of umami substances is not unique in the hamster, but is similar to that of sodium salts, and is mediated exclusively via the chorda tympani.

Animals↗