Biomedical subjects

Masaru Sato

Publications and source records attributed to Masaru Sato.

At least 19 recordsLinked to original sources

PubMed2006

Long-term maxillomandibular skeletal and dental changes in children with cleft lip and palate after maxillary distraction.

Long-term skeletal and dental changes were examined in 8 children with cleft lip and palate who underwent maxillary distraction to allow the maxilla to catch up to their mandibular growth at the treatment point. Changes in the overjet (OJ), overbite (OB), and positions of the anterior nasal spine (ANS), upper incisors (U1), pogonion (Pog), and lower incisors (L1) were measured on preoperative to 36 months postoperative lateral-cephalograms. In most of the children, the long-term changes after the maxillary distraction resulted in an inferior growth of the maxilla and anteroinferior growth of the mandible. This seems to suggest that maxillary distraction performed during childhood needs considerable overcorrection. However, if the maxilla is distracted to an adult position during childhood, the masticatory functions of the children will markedly deteriorate until their jaws grow. Therefore, we believe that one goal of maxillary distraction during childhood can be to allow the maxilla to catch up to the mandibular growth of the children at the treatment point.

Adolescent↗

PubMed2006

Synthesis and some properties of binuclear ruthenocenes bridged by oligoynes: formation of bis(cyclopentadienylidene)cumulene diruthenium complexes in the two-electron oxidation.

The monoynes [Rc*C[triple bond]CRc*] and [Rc'C[triple bond]CRc'] were obtained in improved yields using [Mo(CO)6]/2-FC6H5OH as a catalyst in the alkyne metathesis of [Rc*C[triple bond]CMe] and [Rc'C[triple bond]CMe], respectively (Rc = ruthenocenyl, Rc* = 1'',2'',3'',4'',5''-pentamethylruthenocenyl, and Rc' = 2',3',4',5'-tetramethylruthenocenyl groups). The diynes [Rc*(C[triple bond]C)2Rc*] and [Rc'(C[triple bond]C)2Rc'] were synthesized by the oxidative coupling of the corresponding terminal ethynes in good yields. The triyne [Rc*(C[triple bond]C)3Rc*] and the tetrayne [Rc*(C[triple bond]C)4Rc*] were prepared by the hetero- and homocoupling of [Rc*C[triple bond]CC[triple bond]CH], which was obtained from the reaction of [Rc*C[triple bond]CCHO] with Li[N2CSiMe3], respectively. Although the oxidation waves did not always exhibit a clear two-electron oxidation process, the oxidation potentials shifted to a lower potential with an increase in the number of methyl substituents on the ruthenocenyl ring, and shifted to a higher potential with the increase in the number of C[triple bond]C units; this result is in contrast to that found in the [Rc(CH=CH)(n)Rc] series. The chemical oxidation of [Rc'C[triple bond]CRc'] yielded a stable two-electron-oxidized species, the structure of which was confirmed by X-ray crystallography to be [Ru2(mu2-eta(6):eta(6)-C5Me4C=CC5Me4)(eta-C5H5)2](BF4)2. Changing the substituents (Rc, Rc*, and Rc') had no effect on the chemical oxidation, but in the case of the Rc' series the Me substituent increased the stability of the two-electron-oxidized species in solution. The diyne [Rc*(C[triple bond]C)2Rc*] and the triyne [Rc*(C[triple bond]C)3Rc*] also gave a similar but unstable two-electron-oxidized species. In acetone or acetonitrile, the two-electron-oxidized species of [Rc*C[triple bond]CRc*] and [Rc*(C[triple bond]C)2Rc*] gradually formed the corresponding bis(fulvene)-type complexes. This implies that the two-electron-oxidized species of [Rc*(C[triple bond]C)(n)Rc*] are destabilized with the increasing n.

Journal Article↗

PubMed2005

Circadian rhythms of ocular melatonin in the wrasse Halichoeres tenuispinnis, a labrid teleost.

Using in vivo and in vitro methods we studied the regulation of ocular melatonin rhythms in the wrasse Halichoeres tenuispinnis, by either light or the circadian clock. Rhythmic changes in ocular melatonin levels under light-dark (LD) cycles were persistent under constant darkness (DD), and had a circadian periodicity of approximately 24h. However, ocular melatonin levels remained low under constant light conditions. When wrasse were exposed to a single 6-h light pulse at three different circadian phases under DD, phase-dependent phase shifts in the circadian rhythms of ocular melatonin were observed. When eyecups were prepared during mid-light periods or at the onset of darkness, and incubated in vitro in either light or dark periods, both time and light conditions affected melatonin release. These results indicate that the melatonin rhythms in the wrasse eye are driven by an ocular circadian clock that is entrained to LD cycles via local photoreceptors.

Animals↗

PubMed2005

Long-term skeletal and dental changes in patients with cleft lip and palate after maxillary distraction: a report of three cases treated with a rigid external distraction device.

We examined long-term skeletal and dental changes in three patients with cleft lip and palate who underwent maxillary distraction using a rigid external distraction device. Two were children, and one was an adult. Changes in the overjet (OJ), overbite (OB), and positions of the anterior nasal spine (ANS), upper incisors (U1), pogonion (Pog), and lower incisors (L1) were measured on preoperative to 36 months postoperative lateral-cephalograms. In the adult, the positions of all examination points were relatively stable from 6 to 36 months postoperatively, and the OJ and OB were maintained at over 2 mm at 36 months. In the children, the positions of ANS and U1 changed inferiorly, Pog and L1 changed anteroinferiorly, and OJ and OB tended to decrease from 6 to 36 months postoperatively. Long-term skeletal and dental stability following maxillary distraction was relatively well maintained in the adult patient. In the children, the maxillomandibular growth was observed after maxillary distraction, but the mandibular overgrowth might have been inhibited by the correction of class III dentoskeletal deformity resulting from the maxillary distraction.

Adult↗

PubMed2005

D-Amino acid dipeptide production utilizing D-alanine-D-alanine ligases with novel substrate specificity.

D-Alanine-D-alanine ligase (Ddl) is an important enzyme in the synthesis of bacterial peptidoglycan. The genes encoding Ddls from Escherichia coli K12 (EcDdlB), Oceanobacillus iheyensis JCM 11309 (OiDdl), Synechocystis sp. PCC 6803 (SsDdl) and Thermotoga maritima ATCC 43589 (TmDdl), the genomic DNA sequences of which have been determined, were cloned and the substrate specificities of these recombinant Ddls were investigated. Although OiDdl had a high substrate specificity for D-alanine; EcDdlB, SsDdl and TmDdl showed broad substrate specificities for D-serine, D-threonine, D-cysteine and glycine, in addition to D-alanine. Four D-amino acid dipeptides were produced using EcDdlB, and D-amino acid homo-dipeptides were successfully produced at high yields except for D-threonyl-D-threonine.

Amino Acid Sequence↗

PubMed2004

Synthesis and redox behavior of ruthenocene-terminated oligoenes: characteristic and stable two-electron redox system and lower potential shift of the two-electron oxidation wave with elongating conjugation.

Ruthenocene-terminated butadienes and hexatrienes were prepared by the Wittig reaction of 3-ruthenocenyl-2-propenals with ruthenocenylmethylphosphonium salts and the Mukaiyama coupling of the propenals, respectively. Cyclic voltammetry of these complexes indicated that they were involved in a stable two-electron redox process. The oxidation potentials for ruthenocene-terminated oligoenes shifted progressively to lower potential with the increasing CH==CH units as follows: Rc--Rc (0.32 V)>RcCH==CHRc (+0.09 V)>Rc(CH==CH)(2)Rc (-0.06 V)>Rc(CH==CH)(3)Rc (-0.07 V), (Rc=ruthenocene). The tendency is in remarkable contrast to that in the successive one-electron redox process. These complexes were chemically oxidized to give stable crystalline solids, whose structures were confirmed by NMR spectroscopy and X-ray analysis to be oligoene analogues of a bis(fulvene) complex, for example, [(eta(5)-C(5)Me(5))Ru[mu(2)-eta(6):eta(6)-C(5)H(4)CH(CH==CH)(n)CHC(5)H(4)]Ru(eta(5)-C(5)Me(5))](2+) (n=1 or 2). The DFT calculation of the two-electron-oxidized species reproduced well the fulvene-complex structure for the ruthenocene moieties. Since both the neutral and oxidized species are stable and chemically reversible, this redox system may be serviceable as a two-electron version of the ferrocene one-electron redox system.

Journal Article↗

PubMed2004

Synergistic effects of mupirocin and an isoflavanone isolated from Erythrina variegata on growth and recovery of methicillin-resistant Staphylococcus aureus.

The phytochemical 2',4'-dihydroxy-8-gamma,gamma-dimethylallyl-2",2"-dimethylpyrano[5",6":6,7]isoflavanone (bidwillon B) was isolated from Erythrina variegata and its antibacterial properties against methicillin-resistant Staphylococcus aureus (MRSA) were investigated. Bidwillon B inhibited the growth of 12 MRSA strains at minimum inhibitory concentrations (MICs) of 3.13-6.25mg/l, while MICs of mupirocin were 0.20-3.13 mg/l. The minimum bactericidal concentration (MBC) for bidwillon B and mupirocin against MRSA were 6.25-25mg/l (MBC(90): 12.5mg/l) and 3.13-25mg/l (MBC(90): 25mg/l), respectively. When bidwillon B and mupirocin were combined, synergistic effects were observed for 11 strains of MRSA (fractional inhibitory concentration indices, 0.5-0.75). The MBCs of mupirocin in the presence of bidwillon B (3.13 mg/l) were reduced to 0.05-1.56 mg/l. Bidwillon B at MIC values strongly inhibited incorporation of radio-labelled thymidine, uridine, glucose and isoleucine into MRSA cells. Mupirocin showed lower inhibitory effects than bidwillon B on thymidine, uridine and glucose incorporation, but incorporation of isoleucine was completely blocked with this antibiotic. These results indicate that bidwillon B possesses sufficient anti-MRSA activity for inhibiting growth and recovery, and that the compound acts synergistically with mupirocin. The results also suggest that both compounds act on MRSA via different mechanisms. Bidwillon B may prove to be a potent phytotherapeutic and/or combination agent with mupirocin in the elimination of nasal and skin carriage of MRSA.

Anti-Bacterial Agents↗

PubMed2004

Blood-flow and neurosensory changes in the maxillary dental pulp after differing Le Fort I osteotomies.

PURPOSE: The objective of this study was to examine changes in blood flow and the recovery of sensibility in the maxillary dental pulp after two different types of maxillary osteotomies. Study design Nine patients (C-group) who underwent a combined of Le Fort I and horseshoe osteotomy and 14 patients (NC-group) who underwent a single-segment Le Fort I osteotomy were compared. Thirty-two (C-group) and 54 (NC-group) maxillary incisors were examined preoperatively and at 1-7 days, 14 days, and 3, 6, and 12 months postoperatively. The pulpal blood flow (PBF) was measured by laser Doppler flowmetry, and the pulpal sensibility (PS) was investigated by electrodiagnostics. RESULTS: In both groups, the PBF dropped to its lowest value at 1 day after surgery and increased thereafter. Though a temporary drop of the PBF was observed in the NC-group on day 4, the PS recovered earlier in the NC-group than in the C-group. CONCLUSION: These results suggest that the method of maxillary osteotomy influences the postoperative change of the PBF and recovery of the PS in the maxillary teeth.

Adult↗

PubMed2004

Blood-flow change and recovery of sensibility in the maxillary dental pulp during and after maxillary distraction: a pilot study.

OBJECTIVE: To examine the change in blood flow and recovery of sensibility in the maxillary dental pulp during and after maxillary distraction. STUDY DESIGN: The subjects included 5 patients undergoing high Le Fort I osteotomy and maxillary distraction (D-group) and a reference group of 14 patients who underwent a common single-segment Le Fort I osteotomy, 1-stage maxillary advancement, and mandibular setback surgery (C-group). Eleven (D-group) and 54 (C-group) maxillary incisors were assessed preoperatively and at 1-7 days, 14 days, and 3 months postoperatively. Pulpal blood flow (PBF) was measured by laser Doppler flowmetry, and pulpal sensibility (PS) was investigated by electrodiagnostics. RESULTS: From postoperative days 1 to 5 (the latency period), the PBF tended to be higher in the D-group than in the C-group. From day 6 to 3 months postoperatively (during and after maxillary distraction), the PBF values of the 2 groups were similar. The PS remained negative up to 14 days postoperatively in both groups. However, at 3 months after the operation, a higher proportion (90.9%) of teeth in the D-group was positive for PS. CONCLUSION: These results suggest that maxillary distraction is a favorable technique for maintenance of PBF and recovery of PS in the maxillary teeth after surgery.

Adolescent↗

PubMed2004

Maxillary distraction in patients with cleft deformity using a rigid external distraction device: a pilot study on the distraction ratio of the maxilla to the device.

We examined the ratio between actual maxillary distraction and the distraction of the rigid external distraction device (Rigid external distraction (RED) system) used for maxillary distraction in patients with a cleft deformity. Twelve patients were examined. The amount of maxillary advancement was measured on lateral cephalograms and divided by the activation amount on the RED system. The value obtained was represented as the distraction ratio of the maxilla to the system. The mean ratio in 10 patients with complete cleft lip, palate, and alveolus (complete cleft) was 0.24. However, the ratios in two patients with cleft lip and alveolus or soft cleft palate (incomplete cleft) were considerably higher than the mean ratios in patients with complete cleft. When the maxilla is distracted in patients with complete cleft using the RED system, the amount of activation on the system needs to be about four times the amount of planned maxillary distraction. However, the distraction ratio may be affected by the type of cleft.

Adolescent↗

PubMed2004

Numerical analysis of the depletion zone formation around a growing protein crystal.

It is expected that a protein depletion zone and an impurity depletion zone are formed around a crystal during protein crystal growth if the diffusion field around the crystal is not disturbed. The growth rate of the crystal may be decreased and the impurity uptake may be suppressed to result in highly ordered crystals if these zones are not disturbed. It is well known that a microgravity environment can reduce convective fluid motion, and this is thought to disturb the depletion zones. Therefore, we expect that crystals grown in space can attain better quality than those grown on the ground. In this study, we estimate the depletion zone formation numerically and discuss the results of crystallization in space experiments. In case of alpha-amylase, most of the crystals form a cluster-like morphology on the ground using PEG 8000 as a precipitant. However, in space, we have obtained a single and high-quality crystal grown from the same sample compositions. We have measured the viscosity of the solution, the diffusion coefficient, and the growth rate of protein crystals on the ground. Applying numerical analysis to these values a significant depletion zone was expected to form mainly due to higher values of the viscosity. This might be one of the main reasons for better quality single crystals grown in space, where the depletion zone is thought to remain undisturbed. For protein crystallization experiments, salts are widely used as a precipitant. However, in that case, reduced concentration depletion zone effects can be expected because of a low viscosity. Therefore, if it is possible to increase the viscosity of the protein solution by means of an additive, the depletion zone formation effect would be enhanced to provide a technique that would be especially effective in space.

Aspergillus oryzae↗

PubMed2004

Design specifications of audio-guidance systems for the blind in public spaces.

The government of Fukuoka City conducted a survey to determine the effectiveness of an audio-guidance system for the blind. The blind participants confirmed the usefulness of the audio-guidance. In addition, the blind participants and the walking instructors also provided various comments and suggestions for the better utilization of audio-guidance systems for smoother transportation. In order for the participants to be able to recognize auditory signals, it was important to be able to hear them at their peak volumes. To understand the actual meaning of announcements, however, the average volumes of the signals were more important than their peak volumes. The blind participants suggested that auditory signals and announcements should provide short and simple messages. The walking instructors provided comments regarding the placement of loudspeakers to enhance auditory localization. They recommended hanging the loudspeakers from ceilings located in front of passengers. Furthermore, the necessity of controlling excess reverberations was indicated in order to better enable blind citizens to recognize and localize the auditory signals. It was suggested that using different auditory signals for different purposes and places was effective for smoother transportation.

Acoustics↗

PubMed2003

A simplified counter diffusion method combined with a 1D simulation program for optimizing crystallization conditions.

We developed a new protein crystallization method has been developed using a simplified counter-diffusion method for optimizing crystallization condition. It is composed of only a single capillary, the gel in the silicon tube and the screw-top test tube, which are readily available in the laboratory. The one capillary can continuously scan a wide range of crystallization conditions (combination of the concentrations of the precipitant and the protein) unless crystallization occurs, which means that it corresponds to many drops in the vapor-diffusion method. The amount of the precipitant and the protein solutions can be much less than in conventional methods. In this study, lysozyme and alpha-amylase were used as model proteins for demonstrating the efficiency of this method. In addition, one-dimensional (1-D) simulations of the crystal growth were performed based on the 1-D diffusion model. The optimized conditions can be applied to the initial crystallization conditions for both other counter-diffusion methods with the Granada Crystallization Box (GCB) and for the vapor-diffusion method after some modification.

Capillary Action↗

PubMed2003

Effects of photic environment on ocular melatonin contents in a labrid teleost, the wrasse Halichoeres tenuispinnis.

The wrasse Halichoeres tenuispinnis is a labrid teleost that exhibits robust circadian rhythms in locomotor activity under constant light (LL). This fish buries itself in the bottom sand during the subjective-night, thereby suggesting that behaviorally it adjusts its circadian clock to avoid photoreception. In this study, we determined ocular melatonin contents of the wrasse under various photic environments and used ocular melatonin to indicate photoreception. Under light-dark (LD) cycles, ocular melatonin contents of the wrasse exhibited a daily rhythm, with higher levels during the dark phase than those during the light phase. The duration of nocturnal melatonin elevation was longer under LD 9:15 than under LD 15:9. Acute exposure to 2-h light during the dark phase resulted in a significant decrease in ocular melatonin at mid-dark in an intensity-dependent manner. However, acute exposure to different intensities of light for 2h during the light phase had only a small effect on ocular melatonin contents at mid-day. Under LL, ocular melatonin contents in the wrasse reared with bottom sand present exhibited circadian rhythms and were significantly higher than those with transluscent acryl pellets on the bottom. These results indicate that the ocular melatonin rhythm in the wrasse is driven both by the photic environment and by a circadian clock, and that the wrasse that buries itself in the bottom sand can perceive low intensity of light.

Animals↗

PubMed2003

An arylbenzofuran and four isoflavonoids from the roots of Erythrina poeppigiana.

An arylbenzofuran, erypoegin F and four isoflavonoids, erypoegins G-J, together with six known compounds were isolated from the roots of Erythrina poeppigiana, and their structures were elucidated on the basis of spectroscopic evidence. Erypoegin F is a rare 2-arylbenzofuran possessing a formyl group from a natural source, and erypoegin I is the first naturally occurring isoflavonoid with a 2-oxo-3-methylbutyl group.

Benzofurans↗

PubMed2003

Isoflavonoids from roots of Erythrina zeyheri.

Five isoflavonoids, (+/-)-7,2',4'-trihydroxy-8,3'-di(gamma,gamma-dimethylallyl)isoflavanone, (3R)-7,4'-dihydroxy-2'-methoxy-6,8-di(gamma,gamma-dimethylallyl)isoflavanone, (3R)-7,2',4'-trihydroxy-6,8-di(gamma,gamma-dimethylallyl)isoflavan, 2',4'-dihydroxy-8-gamma,gamma-dimethylallyl-2",2"-dimethylpyrano-[5,6:6,7]isoflavan and (6aS, 11aS)-3,6a-dihydroxy-9-methoxy-4,10-di(gamma,gamma-dimethylallyl)pterocarpan, along with five known compounds, were isolated from the roots of Erythrina zeyheri. Their structures were established on the basis of spectroscopic evidence, and their antibacterial activities against methicillin-resistant Staphylococcus aureus (MRSA) were estimated by determining minimum inhibitory concentrations.

Anti-Infective Agents↗

PubMed2003

Rabeprazole treatment attenuated Helicobacter pylori-associated gastric mucosal lesion formation in Mongolian gerbils.

BACKGROUND AND AIM: Although rabeprazole (RPZ), a proton pump inhibitor, has been reported to have a bactericidal effect on Helicobacter pylori (H. pylori), no studies have been conducted regarding the effect of RPZ on gastric mucosal lesion formation caused by this bacterium. In the present study, we investigated the effect of RPZ on H. pylori-associated gastric mucosal lesion formation. METHODS: Sixty-two male Mongolian gerbils were inoculated with H. pylori (ATCC43504) (Hp group) and 60 gerbils with the culture media alone (control group). Some gerbils in the Hp group and in the control group were injected with RPZ (1 mg/kg/day, for 7 days) at the 5th week. Gerbils were evaluated at the 12th, 24th and 48th weeks. RESULTS: In the Hp group, all gerbils were persistently infected for 24 weeks, but 36% became negative for H. pylori at the 48th week. In the Hp + RPZ group, 18% of gerbils at the 12th week, 40% at the 24th week, and 80% at the 48th week, became negative for H. pylori. The level of neutrophil infiltration was significantly decreased in the Hp + RPZ group in comparison to the Hp group, possibly through the effects of RPZ on initial bacterial colonization and resultant inflammation. Even in the gerbils that became H. pylori-negative, the level of neutrophil infiltration was lower in the Hp + RPZ group than in the Hp group. RPZ treatment significantly increased the level of the reduced form of glutathione (GSH) at the 48th week. The elevated levels of the reduced form of GSH may have been reduced by an antioxidation process in the H. pylori-positive Hp + RPZ group. CONCLUSION: Administration of RPZ not only inhibited gastric H. pylori colonization, but also reduced gastric mucosal inflammation in gerbils, possibly through its antibacterial action as well as pharmacological recruitment of the reduced form of GSH.

2-Pyridinylmethylsulfinylbenzimidazoles↗

PubMed2003

Changes in bite force and dentoskeletal morphology in prognathic patients after orthognathic surgery.

OBJECTIVE: We sought to evaluate the changes in bite force and dentoskeletal morphology in prognathic patients after orthognathic surgery. STUDY DESIGN: Twenty-four patients underwent orthognathic surgery to correct Class III skeletal and dental malocclusions. Ten patients who underwent Le Fort I and bilateral sagittal split ramus osteotomy of the mandible (ie, surgical correction of 2 jaws) and 14 patients who underwent only bilateral sagittal split ramus osteotomy (ie, surgical correction of 1 jaw) were compared. Bite force was measured preoperatively and at 3, 6, and 12 months postoperatively. The dentoskeletal morphology was assessed through lateral cephalograms obtained preoperatively and 12 months postoperatively. RESULTS: Twelve months postoperatively, the bite force was significantly greater in the patients who underwent surgery on 1 jaw than in the patients who underwent surgery on 2 jaws. Significant decreases in the gonial angle, occlusal plane angle, and anterior facial height were observed postoperatively in the patients with 1 surgically corrected jaw, but not in the patients with 2 surgically corrected jaws. Patients with 2 surgically corrected jaws experienced a greater increase in the Frankfort mandibular plane angle and a greater decrease in the posterior facial height than did those with 1 surgically corrected jaw. CONCLUSION: The difference in the preoperative-to-postoperative change in dentoskeletal morphology between the 2 groups is one of the factors responsible for the significant difference in postoperative bite force between the 2 groups.

Adolescent↗