Biomedical subjects

M Otsuki

Publications and source records attributed to M Otsuki.

At least 91 records · Page 5Linked to original sources

PubMed1999

[The study of the anesthetic action of halothane on the rat spinal cord by fos immunoreactivity].

This study was performed to examine the anesthetic action of halothane on the spinal cord of rats by using fos immunoreactivity, a marker for neuronal activity following noxious stimulation. Sprague-Dawley rats were injected with 150 microliters of 5% formalin subcutaneously into the left hindpaw. Control group (n = 5) received 100% oxygen for 3 hours after injection. 1 MAC group (n = 5) and 1.5 MAC group (n = 5) of rats were anesthetized with 1 MAC or 1.5 MAC halothane, respectively, for 3 hours after injection. The number of fos immunoreactive cells was counted in the lumbar spinal cord of each rat. All rats showed escape reactions against noxious stimulation in the control group. In the 1 MAC and 1.5 MAC groups, two of five rats showed response to noxious stimulation and the another three showed no response, respectively. There was profound relation between the responding rats and the expression of fos immunoreactivity in the spinal dorsal horn. The number of fos immunoreactive cells decreased in the cord of rats that showed no response to noxious stimulation by halothane 1 or 1.5 MAC. These findings suggest that halothane has analgesic action on spinal nociceptive neurons in the rats on the condition that its reactions to noxious stimulation are suppressed by halothane of any concentration.

Anesthesia, Inhalation↗

PubMed1999

Biological basis for clinical success: pulp protection and the tooth-restoration interface.

This article provides biological and technological information that strengthens clinicians' understanding of cohesive hybridization and pulp therapy in order to support their routine use of bonding and resin systems. Utilizing cohesive systems, clinicians should experience several advantages over traditional water-soluble base and liner systems. When properly applied, cohesive hybridization of vital dentin prevents immediate postoperative hypersensitivity under all restorations and completely seals the entire tooth-restoration interface, which provides a reduction in recurrent caries.

Animals↗

PubMed1999

The effects on pulp tissue of microleakage in resin composite restorations.

The purpose of this study was to evaluate histopathologically the effect on pulp tissue of microleakage in resin composite restorations. Seventy-two class V cavities were prepared on buccal surfaces of monkeys and divided into 3 groups, F, O, and S. Every cavity was etched with 37% phosphoric acid. In group F cavities, each cavity was restored with photo-curable composite without any dentin adhesives. In group O, the cavities were left unfilled. In group S, each cavity was treated with a dentin adhesive system and restored with a restorative composite. After 3, 30, or 90 days, animals were sacrificed and the subjected teeth were immediately removed, then fixed and decalcified. Following sectioning and staining with hematoxylin and eosin or Taylor's modified bacteria staining, each sample was examined with a light microscope. In most teeth with group S cavities, bacterial invasion was not found indicating excellent marginal sealing. The pulpal reaction was much less than that in other groups. In group F as well as in group O, bacteria were frequently observed in the cavity; however, bacteria penetrated into dentinal tubules more in group F than in group O at 30 and 90 days. A correlation between the presence of bacteria and pulpal inflammation was strongly indicated. It was suggested that a leaky restoration was more harmful to the pulp than an open prepared cavity without restoration.

Acid Etching, Dental↗

PubMed1998

Stimulatory effects of vanadate on amylase release from isolated rat pancreatic acini.

The effects of vanadate on exocrine pancreatic function were examined in isolated rat pancreatic acini. Vanadate caused a concentration-dependent stimulation of amylase release above a concentration of 1 mM. Co-incubation of vanadate with vasoactive intestinal polypeptide, 8-bromoadenosine 3':5'-cyclic monophosphate, and the Ca2+ ionophore A23187 produced a synergistic pattern of amylase release, whereas co-incubation with cholecystokinin octapeptide (CCK-8), carbamylcholine, and 12-O-tetradecanoylphorbol 13-acetate produced an additive effect. Vanadate alone had no influence on acinar cyclic AMP content, Ca2+ efflux, or intracellular Ca2+ concentration. However, preincubation with vanadate prevented the plateau phase of CCK-8-induced Ca2+ transient increase from returning to baseline. Moreover, depletion of the intracellular Ca2+ pool by pretreatment of acini with CCK-8 in Ca2+-free medium (plus ethyleneglycol bis[beta-aminoethylether]-N,N'-tetraacetic acid) had no effect on subsequent stimulation by vanadate, although it abolished the response to both CCK-8 and carbamylcholine stimulation. The protein kinase C (PKC) inhibitors staurosporine and calphostin C significantly inhibited vanadate-stimulated amylase release, whereas the protein tyrosine kinase inhibitor genistein had no inhibitory effect. Moreover, vanadate caused a significant translocation of PKC from cytosol to membrane fraction in pancreatic acinar cells. This translocation was inhibited significantly by staurosporine and calphostin C but not by genistein. These results suggest that vanadate acts directly on pancreatic acini and stimulates amylase release by activating PKC without an effect on Ca2+ mobilization, cyclic AMP, or protein tyrosine kinase.

8-Bromo Cyclic Adenosine Monophosphate↗

PubMed1998

Relationship between circulating vascular cell adhesion molecule-1 and microvascular complications in type 2 diabetes mellitus.

The soluble form of the vascular cell adhesion molecule-1 (VCAM-1) is detectable in human sera and is elevated in diabetic patients, with unknown clinical significance. In the present study, the relationship between serum soluble VCAM-1 and diabetic microvascular complications (retinopathy, nephropathy, and neuropathy) was evaluated in 95 Japanese patients with Type 2 diabetes mellitus (DM). Serum soluble VCAM-1 concentration was higher in patients with more advanced stages of retinopathy as well as nephropathy. There was a significant correlation between soluble VCAM-1 and log10 (urinary albumin excretion) in 69 patients with normal serum creatinine levels (r = 0.51, p < 0.0001) and a significant correlation between soluble VCAM-1 and log10 (serum creatinine) in all the patients (r = 0.83, p < 0.0001). Soluble VCAM-1 concentration was also elevated in patients with neuropathy. There was a significant correlation between soluble VCAM-1 concentration and the number of microvascular complications (r = 0.59, p < 0.0001). However, multivariate regression analysis revealed that only diabetic nephropathy, was associated with the soluble VCAM-1 concentration. The elevation of circulating VCAM-1 level in diabetic nephropathy may result from underlying systemic endothelial dysfunction, increased VCAM-1 production in damaged renal tubular or glomerular epithelial cells and/or decreased renal clearance of this molecule, depending on the stage of nephropathy.

Analysis of Variance↗

PubMed1998

Transcortical sensory aphasia following left frontal infarction.

Two right-handed patients who exhibited language disability after left frontal infarction are described. The patients spoke fluently and exhibited excellent repetition ability from the onset of infarction without exhibiting any oral apraxia, but had deficits in auditory comprehension, naming, reading and writing. In both patients, brain magnetic resonance imaging (MRI) revealed infarction in the left inferior frontal gyrus, the middle frontal gyrus and the anterior part of the lower precentral gyrus. Single photon emission computed tomography (SPECT) revealed decreased blood flow in the same regions as those shown to be infarcted by MRI. The MRI and SPECT findings and the symptoms of these patients suggest that left frontal lesions that encompass Broca's area produce fluent aphasia if the posterior part of the left precentral gyrus or motor cortex remains intact and that lesions anterior to Broca's area and the middle frontal gyrus produce a deficit in auditory comprehension of single words as well as sentences.

Aphasia, Wernicke↗

PubMed1998

Defects of cholecystokinin (CCK)-A receptor gene expression and CCK-A receptor-mediated biological functions in Otsuka Long-Evans Tokushima Fatty (OLETF) rats.

Recent studies in genetically obese and diabetic Otsuka Long-Evans Tokushima Fatty (OLETF) rats suggest defects of cholecystokinin (CCK)-A receptor gene expression and CCK-A receptor-mediated biological functions such as pancreatic juice, protein, and gastric acid secretion. The present studies were undertaken to further examine CCK-A receptor gene expression and CCK-A receptor-mediated biological functions in the pancreas, stomach, and brain of OLETF rats. Expression of the CCK-A receptor gene could not be detected in the stomach, pancreas and brain by the reverse-transcription polymerase chain reaction (RT-PCR) method and Southern blotting of the PCR products. Southern blot analysis of genomic DNA from OLETF and control Long-Evans Tokushima Otsuka (LETO) rats with CCK-A receptor fragment as a probe revealed different restriction bands. Expression of the CCK-B receptor gene was observed in the stomach, pancreas, and brain in both OLETF and LETO rats by the RT-PCR method, with expression of the CCK-B receptor gene markedly enhanced in OLETF rats compared with that in LETO rats. Consistent with the defect of CCK-A receptor gene expression, CCK-A receptor-mediated biological functions were not observed in these organs. Perfused exocrine and endocrine pancreas of OLETF rats were insensitive to CCK stimulation but not to carbamylcholine stimulation. Basal gastric acid and pepsinogen secretions in OLETF rats were higher than in LETO rats. OLETF rats showed a significantly higher average daily food intake, gained body weight faster, and were heavier than LETO rats. The present study confirmed that OLETF rats have CCK-A receptor gene anomalies and demonstrated deficient CCK-A receptor-mediated biological function in the pancreas, stomach, and brain.

Animals↗

PubMed1998

Effects of branched-chain-enriched amino acid solution on insulin and glucagon secretion and blood glucose level in liver cirrhosis.

BACKGROUND: The aim of this study was to determine whether therapeutically used branched-chain amino acids (BCAAs) solution influences glucose metabolism in liver cirrhosis (LC). METHODS: BCAAs solution (200 ml) was infused in LC patients at different stages, and plasma concentrations of glucose and pancreatic hormones were determined. RESULTS: In patients with mild LC, BCAAs caused a significant increase in glucose level (maximal increment, 12.5+/-2.5 mg/dl) with a great increase in insulin (maximal increment, 39.5+/-8.3 microU/ml) and a small increase in glucagon secretion (maximal increment, 101.0+/-16.0 pg/ml). In patients with advanced LC, BCAAs caused a great increase in glucagon secretion (220.5+/-19.4 pg/ml) with only a slight increase in glucose levels (5.8+/-2.2 mg/dl). CONCLUSION: BCAAs solution causes hyperglycemia in mild LC due to insulin resistance, whereas it causes only a slight increase in severe LC due to hepatic glucagon resistance. Thus, there is a possibility that BCAAs solution may lead to hypoglycemia in advanced LC with hepatic glycogen depletion.

Adult↗

PubMed1998

In-vitro and in-vivo antibacterial activities of CS-834, a new oral carbapenem.

We evaluated the in-vitro and in-vivo antibacterial activities of R-95867 and CS-834, a new oral carbapenem which is an ester-type prodrug of R-95867. Against Gram-positive bacteria, R-95867 was as active or two to 256 times more active than cefpodoxime, cefdinir, cefditoren and ofloxacin, while its activity was similar to or two to eight times lower than that of imipenem. Against most Gram-negative bacteria it was as active or two to 1024 times more active than the other compounds tested. Against Helicobacter pylori it was two to 64 times more active than orally active anti-H. pylori agents, i.e. amoxycillin, clarithromycin and lansoprazole. It also showed potent bactericidal activity against Staphylococcus aureus and Escherichia coli. R-95867 induced a spherical form in E. coli and showed high affinity for PBP 2 in E. coli. Against systemic infections in mice caused by various bacteria, CS-834 showed an excellent protective effect and its in-vivo efficacy correlated well with the in-vitro activity of R-95867. These results suggest that CS-834 may be effective in the therapy of various bacterial infections.

Administration, Oral↗

PubMed1998

CCK administration after CCK receptor blockade accelerates recovery from cerulein-induced acute pancreatitis in rats.

We examined the effects of treatment with cholecystokinin (CCK) octapeptide (CCK-8) and the CCK receptor antagonist loxiglumide on the recovery of exocrine pancreas in post-acute pancreatitic rats. Acute pancreatitis was induced in rats by intravenous infusion of 20 microg/kg/h cerulein for 4 h. At 24 h after the start of cerulein infusion, rats were divided into nine treatment groups: oral administration of saline (control), or oral administration of 10 or 50 mg/kg body weight loxiglumide twice daily for the first 3 days, followed by saline administration (Loxi-1 and Loxi-2), 10 or 50 mg/kg body weight loxiglumide twice daily for 6 days (Loxi-3 and Loxi-4), oral administration of saline or 10 or 50 mg/kg body weight loxiglumide twice daily for the first 3 days, followed by subcutaneous injection of 2.5 microg/kg body weight CCK-8 twice daily for the next 3 days (CCK-1, CCK-2, and CCK-3), and subcutaneous injection of 2.5 microg/kg body weight CCK-8 twice daily for 6 days (CCK-4). Pancreatic wet weight and biochemical changes were evaluated on day 8 at 12 h after the last treatment. Treatment with loxiglumide (Loxi-3 and Loxi-4) or CCK-8 for 6 days (CCK-4) or with a high dose of loxiglumide for the first 3 days (Loxi-2) significantly suppressed the recovery of pancreatic weight and DNA content compared to saline treatment or to the untreated normal control rats. However, when loxiglumide treatment was followed by 3 days of CCK-8 injections (CCK-2 and CCK-3), pancreatic protein and DNA content recovered to levels comparable to or above the control levels. The most remarkable increase in enzyme content was obtained in postpancreatitic rats treated with high-dose loxiglumide for the first 3 days, followed by CCK-8 injection (CCK-3). On the other hand, 6 days of CCK-8 treatment (CCK-4) had no significant influences on pancreatic enzyme contents. These results suggest that the most favorable strategy for the treatment of acute pancreatitis is to give high-dose loxiglumide during the early stage for only a short period, followed by CCK-8 administration.

Acute Disease↗

PubMed1998

Exocrine pancreatic physiology: overview.

Exocrine pancreatic physiology has been actively investigated in Japan during the past 30 years. We selected three areas and reviewed them for this article. The selected areas are perfusion of the isolated pancreas, cholecystokinin (CCK)-releasing factor from pancreatic juice (monitor peptide), and genetically diabetic rats. The aim of this article is to present a brief overview of the selected areas of exocrine pancreatic physiology in Japan so that future research can be productively directed.

Animals↗

PubMed1998

Carcinoma of the stomach with hyperkeratosis palmaris et plantaris and acanthosis of the esophagus.

A 59-yr-old man with carcinoma of the stomach, concurrent acquired hyperkeratosis (tylosis) of the palms and soles, and acanthosis of the esophageal mucosa is reported. He presented the tylosis and esophageal lesions when the carcinoma was evident. Resection of the stomach resulted in diminution of the skin and esophageal lesions. The association of sporadic tylosis and carcinoma of the stomach is extremely rare. This is the first case report documenting the association of gastric cancer, tylosis, and acanthosis of the esophageal mucosa.

Adenocarcinoma↗

PubMed1998

Effects of endoscopic variceal ligation on portal hypertensive gastropathy and gastric mucosal blood flow.

OBJECTIVE: Portal hypertensive gastropathy (PHG) has been recognized recently as a potential cause of upper gastrointestinal tract bleeding and is associated with a change in gastric hemodynamic indices in cirrhotic patients with portal hypertension. Endoscopic variceal ligation (EVL) is the treatment of choice for esophageal varices. We investigated the early effect of EVL on PHG and gastric mucosal blood flow (GMBF). METHODS: We examined 35 cirrhotic patients who were treated by EVL. PHG was evaluated endoscopically and GMBF was measured by laser Doppler flowmetry before and 1 or 2 wk after EVL. RESULTS: After EVL, only two patients (5.7%) developed severe PHG, 6 (17.1%) developed mild PHG, and 27 (77.1%) showed no change in endoscopic appearance of PHG. In those patients who developed PHG, EVL significantly decreased GMBF at the corpus (p < .05). However, no significant changes of GMBF at the corpus were noted after EVL in those patients who had no worsening of endoscopic features. EVL had no effect on GMBF at the antrum in any patients. CONCLUSIONS: Endoscopic variceal ligation is safe and does not lead, at least within 1-2 wk, to worsening of gastropathy in most cases. Our finding that gastropathy developed in the presence of reduced GMBF may suggest that PHG develops as a result of congestion caused by blockade of gastric blood drainage rather than by hyperemia.

Adult↗

PubMed1998

CCK-, secretin-, and cholinergic-independent pancreatic fluid hypersecretion in protease inhibitor-treated rats.

Plasma cholecystokinin (CCK) levels in fed rats increased from 2.59 +/- 0.13 pmol/l to the peak of 27.6 +/- 4.1 pmol/l at 1 h after a single oral administration of synthetic protease inhibitor (PI; ethyl N-allyl-N-[(E)-2-methyl-3-[4-(4-amidino-phenoxycarbonyl)phenyl] propenoyl] amino acetate methansulfonate; 20 mg/kg body wt), but then returned to the preloading value at 12 h after administration. The pancreatic fluid secretion, rich in chloride but poor in bicarbonate, was significantly elevated at 6-12 h postfeeding (100.9 +/- 8.2 vs. 27.3 +/- 2.3 microliters/30 min in control rats, P < 0.01). Loxiglumide (50 mg.kg body wt-1.h-1), atropine (100 micrograms.kg body wt-1.h-1), or antisecretin serum (100 microliters/rat) at 12 h postfeeding did not modify the fluid hypersecretion. Loxiglumide, when given together with PI, completely abolished fluid hypersecretion, but it could not inhibit hypersecretion when applied 3 h after PI treatment. Labeling with 5-bromo-2'-deoxyuridine showed active proliferation of acinar cells at 3 h after PI treatment (3.56 +/- 0.29% vs. 0.46 +/- 0.08% in control, P < 0.001), but not in rats given loxiglumide together with PI. In rats that fasted from 12 h before to 12 h after PI feeding, neither pancreatic fluid hypersecretion nor active proliferation of acinar cells was observed. These results suggest that pancreatic fluid hypersecretion in fed rats at 6-12 h after PI treatment is caused not by CCK-, secretin-, or cholinergic-dependent mechanisms but probably by acinar cell proliferation.

Acetylcholine↗

PubMed1998

Supramaximal CCK and CCh concentrations abolish VIP potentiation by inhibiting adenylyl cyclase activity.

Exocrine pancreatic secretion stimulated by vasoactive intestinal polypeptide (VIP), which acts through the adenylyl cyclase-cAMP pathway, is potentiated by stimulation with other secretagogues such as CCK and carbachol (CCh). However, the potentiating effect is abolished by the same secretagogues at supramaximal concentrations. In the present study, we examined the mechanisms by which supramaximal concentrations of CCK octapeptide (CCK-8) or CCh reduce the VIP-induced potentiation of amylase secretion from isolated rat pancreatic acini. VIP-stimulated amylase secretion was potentiated by submaximal stimulatory concentrations of CCK-8 and CCh but was reduced by the same reagents at higher concentrations. Supramaximal concentrations of CCK-8 or CCh also reduced forskolin-induced potentiation of amylase release but did not reduce that induced by 8-bromo-cAMP. Moreover, supramaximal concentrations of CCK-8 or CCh inhibited VIP-stimulated intracellular cAMP production as well as adenylyl cyclase activity. 12-O-tetradecanoylphorbol 13-acetate (TPA) also reduced the magnitude of the potentiation of amylase release caused by VIP plus CCK-8 or CCh, although TPA itself decreased neither VIP-stimulated adenylyl cyclase activity nor intracellular cAMP accumulation. These results indicate that supramaximal concentrations of CCK-8 and CCh reduce the potentiating effect of VIP and forskolin on amylase secretion by inhibiting the adenylyl cyclase activity. In addition, protein kinase C is suggested to be partly implicated in this inhibitory mechanism. The mechanisms that lead to such inhibition may be interlinked but distinct from each other.

8-Bromo Cyclic Adenosine Monophosphate↗

PubMed1998

Slowly progressive pure word deafness.

Among the reports of primary progressive aphasia, there are few about patients who exhibited progressive pure word deafness with detailed auditory and radiological examination as well as neuropsychological assessment. We describe a 67-year-old right-handed man who exhibited slowly progressive pure word deafness over a period of 9 years without exhibiting any other cognitive or mental deterioration. Magnetic resonance imaging of his brain revealed generalized cortical atrophy, particularly in the left superior temporal region. Auditory examination revealed severe disability in discriminating each syllable or mora of Japanese words despite adequate auditory acuity. He also showed impairment in temporal auditory discrimination assessed by the click fusion test and the click counting test. His ability to discriminate meaningful environmental sounds was mildly impaired. We discuss the pathophysiology of slowly progressive pure word deafness over a period of many years which was not complicated by other language or cognitive dysfunctions.

Aged↗

PubMed1998

Comparison between Er:YAG laser and conventional technique for root caries treatment in vitro.

Effective ablation of dental hard tissues by means of the erbium-doped:yttrium-aluminum garnet (Er:YAG) laser has been reported recently, and its application to caries removal and cavity preparation has been expected. However, few studies have investigated the capability of the Er:YAG laser to treat caries. In the present study, the effectiveness of caries removal by using an Er:YAG laser in vitro was compared with that of conventional mechanical treatment. Thirty-one extracted human teeth with root caries were used. Half of the caries in each tooth was treated with the Er:YAG laser, and the other was removed with a conventional bur or was left untreated as a control. Laser treatment was performed by means of a combination of contact and non-contact irradiation modes with cooling water spray, with a new fiber delivery and contact probe system. Conventional bur treatment was conducted by means of a low-speed micromotor. Measurements of the time required for caries removal, histopathological observations of decalcified serial sections, scanning electron microscope (SEM) observations, and hardness measurements of the treated cavity-floor dentin were performed for each treatment. Due to the careful irradiation technique, a longer treatment time was required for the complete removal of carious dentin by the Er:YAG laser. However, the Er:YAG laser ablated carious dentin effectively with minimal thermal damage to the surrounding intact dentin, and removed infected and softened carious dentin to the same degree as the bur treatment. In addition, a lower degree of vibration was noted with the Er:YAG laser treatment. The SEM examination revealed characteristic micro-irregularities of the lased dentin surface. Our results show that the Er:YAG laser system is promising as a new technical modality for caries treatment.

Dental Cavity Preparation↗

PubMed1998

[Effect of positive end-expiratory pressure on respiration and hemodynamics in dogs with pulmonary edema caused by increased membrane permeability].

The effect of PEEP on the extravascular lung water, respiratory mechanics and hemodynamics were studied in dogs with oleic acid-induced pulmonary edema. The dogs were randomized into one of three groups according to PEEP of 0, 5 and 10 cmH2O, 60 minutes after oleic acid (0.1 ml.kg-1) injection. PEEP improved oxygenation accompanied by increased FRC and DLco. However, oxygen delivery decreased in association with the decreased cardiac index caused by application of PEEP. PEEP failed to decrease the extravascular lung water volume measured by double-indicator dilution technique after lung edema formation.

Animals↗