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Biomedical subjects

M Irie

Publications and source records attributed to M Irie.

At least 37 records · Page 2Linked to original sources
PubMed2001

Can conditioned histamine release occur under urethane anesthesia in guinea pigs?

Many clinical and experimental data have shown that learning can occur under general anesthesia. To clarify this possibility with respect to allergic reactions, particularly asthmatic responses, we first established classical conditioned histamine release in response to a neutral odor by using pairings of the odor and an inhaled antigen for five sessions (Experiment 1) and then investigated whether conditioned histamine release into the plasma, bronchoalveolar lavage fluid (BALF), and lung tissue, which followed such a conditioning procedure, would be produced in urethane-anesthetized guinea pigs in the presence or absence of antigen (Experiment 2). Ovalbumin (OA) was used as the unconditioned stimulus (US) and dimethylsulfide (DMS) served as the conditioned stimulus (CS) in both experiments. In Experiment 1, the plasma histamine levels in the conditioned group increased significantly more than those of the unpaired control group in response to the CS during consciousness. In Experiment 2 in the absence of antigen, however, no significant differences in the histamine levels were found regarding the groups (DMS, triethylamine, saline, or unsensitized) or the time course (before, immediately, 5 min, and 10 min after the inhalations) during anesthesia, except for the finding that the histamine levels in the lung tissue specimens from the DMS group were significantly higher than those from the triethylamine group. In Experiment 2 in the presence of antigen, there was a significant increase in the plasma histamine levels after exposure to the US, irrespective of the presence of the CS, however, no significant difference in the histamine levels was observed between the US and the CS+US groups. These results indicated that a classically CS might not induce asthmatic responses under anesthesia.

Anesthesia, Intravenous↗
PubMed2001

Ribonuclease T2.

Explore the source record for details and available documents.

Amino Acid Sequence↗
PubMed2001

Current luting cements: marginal gap formation of composite inlay and their mechanical properties.

OBJECTIVE: The aims of this investigation were to investigate the effect of thermocycling on the marginal gap formation of composite inlays using three types of luting cements (Compolute, PermaCem, Fuji Plus, Panavia 21: as a control) and on mechanical properties of four luting cements. METHODS: The maximum marginal gap in the dentin cavity of each of ten resin inlay specimens in each group, was measured by a microscope before and after 10,000 thermocycles. The dimensional change, shear bond strength to dentin, and material and conditions for flexural strength and modulus testing were examined. RESULTS: Compolute and Panavia 21 showed marginal gaps of approximately 10 microm before thermocycling. In contrast, the gap widths after thermocycling was significantly wider. Although the gap widths of PermaCem and Fuji Plus were approximately 60-110 microm prior to thermocycling, they were significantly smaller in width after thermocycling. Statistical differences in the shear bond strength to dentin were not observed before or after thermocycling for all materials. The flexural strength and modulus were significantly increased after thermocycling compared with three products and with all four products, respectively. SIGNIFICANCE: The mechanical properties of all four luting cements were closely related to their marginal gap formations and these mechanical factors have important roles in determining their marginal gap formations.

Chi-Square Distribution↗
PubMed2001

Influences of cholinergic neurotoxin ethylcholine aziridinium ion on circadian rhythms in rats.

To investigate whether damages of cholinergic neurons in the brain produce aging-like changes in circadian rhythms, we examined the influences of intracerebroventricular injection of cholinergic neurotoxin ethylcholine aziridinium ion (AF64A, 5 nmol/5 microl) on circadian rhythms in rats, by measuring locomotor activity and body temperature with the automatic behavioral measurement system combined with the telemetry. Daily rhythms in locomotor activity and body temperature were observed in AF64A-treated rats under a 12:12 h light:dark (LD) cycle, however, in AF64A-treated rats, the amplitude of activity and temperature rhythms was significantly decreased, the phase of the both rhythms was advanced and the amount of activity was decreased, compared with control rats. Locomotor activity and body temperature also showed a circadian rhythm in AF64A-treated rats under the constant dark condition with the period similar to that in the control rats. The present findings are in accordance with the observation in aged animals in which cholinergic hypofunction are often observed, suggesting that hypofunctions of the cholinergic systems in the brain might be involved in aging-like changes in the circadian rhythms.

Acetylcholine↗
PubMed2001

Psychosocial factors as a potential trigger of oxidative DNA damage in human leukocytes.

Although numerous studies have been carried out on the stress-cancer linkage, the results are still inconclusive. One of the useful, but rarely applied, methods to assess this linkage is to examine the relationship between psychosocial stress and cancer-predisposing genetic alterations simultaneously. We investigated whether various psychosocial factors can be associated with the levels of 8-hydroxydeoxyguanosine (8-OH-dG), a biomarker of cancer-related oxidative DNA damage, in peripheral blood leukocytes in 362 healthy workers (276 males and 86 females). After adjustments for age, body mass index, cigarette smoking, and alcohol use, female subjects showed positive relationships between the amount of 8-OH-dG and the Tension-Anxiety, Depression-Rejection, Anger-Hostility, Fatigue, and Confusion scores of the Profile of Mood States, respectively. The levels of 8-OH-dG also increased reliably in the female subjects who had poor stress-coping behaviors, particularly wishful thinking strategy, in the NIOSH general job stress instrument. There were positive relationships of the 8-OH-dG levels to average working hours, a self-blame coping strategy, and recent loss of a close family member in male subjects. These findings in a nonclinical sample of healthy adults not only provide evidence of a stress-cancer linkage, but also suggest possible sex differences in the mechanisms of stress-related cancer initiation.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed2001

Amino acid sequence of a trypsin inhibitor from a Spirometra (Spirometra erinaceieuropaei).

A trypsin inhibitor that is highly homologous with bovine pancreatic trypsin inhibitor (BPTI) was co-purified along with RNase from Spirometra (Spirometra erinaceieuropaei). The amino acid sequence of this inhibitor (SETI) and the nucleotide sequence of the cDNA encoding this protein were determined by protein chemistry and gene technology. SETI contains 68 amino acid residues and has a molecular mass of 7,798 Da. SETI has 31 amino acid residues that are identical with BPTI's sequence, including 6 half-cystine and 5 aromatic amino acid residues. The active site Lys residue in BPTI is replaced by an Arg residue in SETI. SETI is an effective inhibitor of trypsin and moderately inhibits a-chymotrypsin, but less inhibits elastase or subtilisin. SETI was expressed by E. coli containing a PelB vector carrying the SETI encoding cDNA; an expression yield of 0.68 mg/l was obtained. The phylogenetic relationship of SETI and the other BPTI-like trypsin inhibitors was analyzed using most likelihood inference methods.

Amino Acid Sequence↗
PubMed2001

Enzymatic properties of sialic acid binding lectin from Rana catesbeiana modified with a water-soluble carbodiimide in the presence of various nucleophiles.

The anti-tumor activity of sialic acid binding lectin from Rana catesbeiana (cSBL) was increased by chemical modification with a water-soluble carbodiimide (EDC) in the presence of nucleophiles such as ethylenediamine and glycine methylester. Investigations on ribonuclease (RNase) activities of the modified cSBLs were conducted to elucidate the fundamental mechanisms underlying enhancement of the anti-tumor activity conferred by these modifications. The following three characteristics were observed with modification. (i) RNase activity of the modified cSBL was enhanced towards double stranded RNA and RNA-oligo dA hybrids. The activity increase was observed even under physiologic ionic strength conditions; (ii) RNase activity of the modified cSBL towards single stranded RNA and poly U decreased, while the activity towards poly C was unaffected; (iii) the base preference of the B2 base recognition site of modified cSBL decreased for guanine. On the contrary, the preference for cytosine and adenine increased. This result may explain why the RNase activity towards poly C was not affected by EDC-modification as mentioned above.

Amphibian Proteins↗
PubMed2001

Amino acid sequence and characterization of a rice bran ribonuclease.

A base-nonspecific and acid ribonuclease (RNase Os) belonging to the RNase T2 family was purified from rice bran to a homogeneous state by SDS-PAGE. The primary structure of RNase Os was determined by protein chemistry and molecular cloning. The RNase Os was a simple protein and consisted of 205 amino acid residues. Its molecular weight was 22578 and its amino acid sequence showed that it was most similar to barley RNase among the known RNase T2 family enzymes having 157 amino acid residues identical with barley RNase. However, its N-terminus was blocked by a gamma-pyroglutamyl residue. The optimal pH of RNase Os was around 5.5. The base preference at the B1 and B2 site of RNase Os was estimated from the rates of hydrolysis of 16 dinucleoside phosphates, to be guanine as the case of RNase LE from tomato. RNase Os was successfully expressed from yeast cells using the E. coli yeast expression vector pYE-RNAP.

Amino Acid Sequence↗
PubMed2001

Effect of modification of the carboxyl groups of the sialic acid binding lectin from bullfrog (Rana catesbeiana) oocyte on anti-tumor activity.

The sialic acid binding lectin from bullfrog Rana catesbeiana oocyte (cSBL) is known to have anti-tumor activity. In order to investigate the relationship between the net charge of cSBL and its anti-tumor effect, cSBL was modified with a water-soluble carbodiimide (EDC) in the presence of three kinds of nucleophiles, taurine, glycine methylester and ethylenediamine. cSBL having four carboxyl groups was partially modified (ca. 2 residues). The anti-tumor activity of modified cSBLs was in the order of ethylenediamine-modified cSBL > glycine methylester-modified cSBL > taurine modified cSBL > or = native cSBL. The results suggested that anti-tumor activity seems to increase with the increase in positive net charge, possibly enhancing the interaction of cSBL with sialoglycoprotein on the surface of tumor cells. The ribonuclease activity of ethylenediamine-modified cSBL decreased with the progress of the reaction, but the number of internalized molecules in the tumor cell increased. Thus, for antitumor activity, a higher incorporation of cSBL with reasonable RNase activity seems to be more important than total RNase activity.

Amino Acid Sequence↗
PubMed2001

Recognition and transport characteristics of nonpeptidic compounds by basolateral peptide transporter in Caco-2 cells.

Recent studies have revealed that diverse compounds lacking peptide bonds, such as valacyclovir and delta-aminolevulinic acid (delta-ALA), can be recognized by H+-coupled peptide transporters (PEPT1 and PEPT2). In the present study, recognition and transport characteristics of nonpeptidic compounds by the basolateral peptide transporter, which is distinct from PEPTs, were compared with those by PEPT1 using the human intestinal Caco-2 cells. [14C]Glycylsarcosine uptake via PEPT1 was inhibited by all nonpeptidic compounds tested. Similarly, most nonpeptidic compounds showed an inhibitory effect on [14C]glycylsarcosine uptake by the basolateral peptide transporter, although some kinds of nonpeptidic compounds, such as valine methyl ester, did not. Direct measurements of valacyclovir and delta-ALA transport revealed that both compounds were able to be transported by the basolateral peptide transporter. Because delta-ALA has been used recently in vitro and in clinical studies as an endogenous photosensitizer for photodynamic therapy, the intestinal transport characteristics of delta-ALA were further examined. Inhibition studies and Eadie-Hofstee plot analysis suggested that delta-ALA transport across the brush-border and basolateral membranes of the intestine was mainly mediated by peptide transporters. In addition, the apical-to-basolateral transport of delta-ALA was greater than that of the opposite direction. These findings provide the first evidence that the intestinal basolateral peptide transporter can recognize and transport nonpeptidic compounds, and play a definitive role in the absorption of delta-ALA.

ATP-Binding Cassette Transporters↗
PubMed2001

Investigation and evaluation of the change in the outpatients flow before and after the move of the hospital.

In order to estimate the changes in the service for outpatients with hospital movement, patient flow investigation has been performed at both old and new hospitals. IC memory card was handed out to each outpatient, and timestamps and places were recorded on the card at the places that the patient have been by using card writers set at each department. By comparing with two results, old and new hospitals, patient-waiting time at payment counter was remarkably shortened because of the effect of order-entry system. However, there were few changes in stay time at clinical departments. From the results, it is found that optimization of booking system was required for improvement of patients flow at clinical departments.

Appointments and Schedules↗
PubMed2001

Effect of a novel insole on the subtalar joint of patients with medial compartment osteoarthritis of the knee.

OBJECTIVE: To assess the efficacy of a lateral wedge insole with elastic strapping of the subtalar joint for conservative treatment of osteoarthritis (OA) of the knee. METHODS: The efficacy of a novel insole with elastic subtalar strapping and a traditional shoe insert wedge insole was compared. Ninety female outpatients with OA of the knee were treated with wedge insoles for 8 weeks. Randomization was performed according to birth date. Standing radiographs with unilateral insole use were used to analyze the femorotibial and talar tilt angles for each patient with and without their respective insole. Visual analog scale (VAS) score for subjective knee pain at the final assessment was compared with that at baseline in both groups. RESULTS: Participants wearing the elastically strapped insole (n = 46) had significantly decreased femorotibial angle (p < 0.0001) and talar tilt angle (p = 0.005) and significantly improved VAS pain score (p = 0.045) in comparison with baseline assessments. These significant differences were not found in the group with the inserted insole (n = 44). CONCLUSION: The novel strapped insole leads to valgus angulation of the talus, resulting in correction of the femorotibial angle in patients with knee OA with varus deformity, and may have a therapeutic effect similar to that of high tibial osteotomy.

Aged↗
PubMed2000

Syntheses of optically active trifluoronorcoronamic acids.

Syntheses of optically active trifluoronorcoronamic acid 6 and its diastereomer 9 are described. Highly stereospecific and diastereoselective S(N)2 cyclization of gamma-cyanohydrins 3a and 3b gave cyclopropyl nitriles 4a and 4b. Hydrolysis of the cyano group and deprotection of the amino group of 4a provide trifluoronorcoronamic acid 6. Hofmann rearrangement of the amide which was generated by hydrolysis of the cyano group and oxidative cleavage of the aryl ring of 4b to provide trifluoro-allo-norcoronamic acid 9.

Amino Acids↗
PubMed2000

Classical conditioning of oxidative DNA damage in rats.

This study investigated whether the formation of 8-hydroxydeoxyguanosine (8-OH-dG), a known oxidative DNA modification relevant to carcinogenicity, can be classically conditioned to a novel taste in order to clarify the possible role of the central nervous system (CNS) or psychological stress on cancer initiation via a classical conditioning mechanism. Male Wistar rats underwent one or two conditioned taste aversion (CTA) experiments in which ferric nitrilotriacetate (Fe-NTA), which has renal toxicity and can induce renal cell carcinoma, served as a visceral unconditioned stimulus (US), and a saccharin solution (SAC) was used as a conditioned stimulus (CS). The 8-OH-dG levels in the group conditioned with the combination of SAC and Fe-NTA significantly increased as compared to those of the uncombined groups by two repeats of the conditioning procedure (P=0.013). The rats that showed a painful response at the Fe-NTA administration had significantly higher values of 8-OH-dG than those without pain (P=0. 003). These results not only provide the first evidence regarding classical conditioning of oxidative DNA damage using the CTA procedure, but also suggest the involvement of the CNS and psychological stress in the pathogenesis of cancer via oxidative DNA damage.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed2000

Crystal structure of a plant ribonuclease, RNase LE.

Ribonuclease LE (RNase LE) from cultured tomato (Lycopersicon esculentum) cells is a member of the RNase T(2) family showing broad base specificity. The crystal structure of RNase LE has been determined at 1.65 A resolution. The structure consists of seven alpha-helices and seven beta-strands, belonging to an alpha+beta type structure. Comparison of the structure of RNase LE with that of RNase Rh, a microbial RNase belonging to the RNase T(2) family, reveals that while the overall folding topologies are similar to each other, major insertions and deletions are found at the N-terminal regions. The structural comparison, an amino acid sequence alignment of the RNase T(2) enzymes, and comparison of the disulfide-bonding pattern of these enzymes show that the structure of RNase LE shown here is the basic framework of the animal/plant subfamily of RNase T(2) enzymes (including a self-incompatibility protein called S-RNase), and the structure of RNase Rh is that of the fungal subfamily of RNase T(2) enzymes (including RNase T(2)). Subsequently, we superposed the active-site of the RNase LE with that of RNase Rh and found that (1) His39, Trp42, His92, Glu93, Lys96, and His97 of RNase LE coincided exactly with His46, Trp49, His104, Glu105, Lys108, and His109, respectively, of RNase Rh, and (2) two conserved water molecules were found at the putative P(1) sites of both enzymes. These facts suggest that plant RNase LE has a very similar hydrolysis mechanism to that of fungal RNase Rh, and almost all the RNase T(2) enzymes widely distributed in various species share a common catalytic mechanism. A cluster of hydrophobic residues was found on the active-site face of the RNase LE molecule and two large hydrophobic pockets exist. These hydrophobic pockets appear to be base binding sites mainly by hydrophobic interactions and are responsible for the base non-specificity of RNase LE.

Amino Acid Sequence↗
PubMed2000

Amino acids and peptides. LVII. Synthetic peptide with a sequence of ribonuclease from Sulfolobus solfataricus, SSR(1-62), does not function as an RNase.

The 62 residue peptide, SSR(1-62), whose sequence corresponds to that of ribonuclease (RNase) from Sulfolobus solfataricus, and its related peptides, SSR(1-22) and SSR(10-62), were chemically synthesized and their RNase activity and DNA-binding activity were examined. The RNase activity assay using yeast RNA or tRNA(fMet) as substrate showed that the synthetic peptide SSR(1-62) did not hydrolyze yeast RNA or tRNA(fMet). These data were not consistent with previous reports that both the native peptide isolated from S. solfataricus [Fusi et al. (1993) Eur. J. Biochem. 211, 305-311] and the recombinant peptide expressed in Escherichia coli [Fusi et al. (1995) Gene 154, 99-103] were able to hydrolyze tRNA(fMet). However, the synthetic SSR(1-62) exhibited DNA-binding activity. In the presence of synthetic SSR(1-62), the cleavage of DNA (plasmid pUCRh2-4) by restriction endonuclease (EcoRI) was not observed, suggesting that synthetic SSR(1-62) bound to DNA protected DNA from its enzymatic digestion. Neither SSR(1-22) nor SSR(10-62) prevented DNA from being cleaved by a restriction enzyme. These findings strongly suggest the importance of not only the N-terminal region of SSR(1-62) but also the C-terminal region for DNA-binding. Circular dichroism spectroscopy of synthetic SSR(1-62) indicated a beta-sheet conformation, in contrast with synthetic SSR(1-22), which exhibited an unordered conformation.

Amino Acid Sequence↗
PubMed2000

Structural requirements for determining the substrate affinity of peptide transporters PEPT1 and PEPT2.

Peptide transporters PEPT1 and PEPT2 transport numerous compounds including small peptides, peptide-like drugs and nonpeptidic compounds such as valacyclovir. PEPT1 and PEPT2 show low and high affinity for most substrates, respectively, but beta-lactam antibiotics without an alpha-amino group are the only known substrates that prefer PEPT1 to PEPT2. The aim of this study was to compare the recognition and affinity of various substrates between rat PEPT1 and rat PEPT2, and to determine the structural requirements influencing the substrate affinity. [14C]Glycylsarcosine uptake by PEPT1- or PEPT2-expressing transfectant was inhibited by di- and tripeptides, but not by amino acids, tetrapeptides or most cyclic dipeptides. All dipeptides and tripeptides examined showed more potent inhibition of [14C]glycylsarcosine uptake via PEPT2 than via PEPT1, irrespective of their charge and structure. Modification of the alpha-amino group of dipeptides reduced their substrate affinity to both transporters, as compared to unmodified dipeptides, but these dipeptides still showed potent inhibitory effects on PEPT2. Among the nonpeptidic substrates tested, only the eight-amino-octanoic acid displayed stronger inhibition of [14C]glycylsarcosine uptake in PEPT1 than in PEPT2. These findings suggest that alpha- or beta-amino carbonyl function is the key structure responsible for the higher affinity for PEPT2 than for PEPT1.

Animals↗