Biomedical subjects

Satoshi Maeda

Publications and source records attributed to Satoshi Maeda.

At least 19 recordsLinked to original sources

PubMed2007

Two-directional elaboration of hydroxyacetone under thermodynamically controlled conditions: allylation or 2-propynylation and aldol reaction.

Enolate generated from O-(tetrahydropyran-2-yl)hydroxyacetone under thermodynamically controlled conditions (1.3 equiv of NaH, THF, 0 degrees C to rt) was allylated at the carbon bearing the protected hydroxy group with very high regioselectively. When tert-BuOH, equivalent to the excessive portion of initially added NaH, was introduced into the mixture followed by addition of aldehyde, aldol reaction took place on the methyl group to give 1-substituted 4-hydroxy-(1E),6-heptadien-3-one in acceptable yields after acidic treatment of the mixture for dehydration and deprotection. Introducing a chiral auxiliary protecting group into hydroxyacetone led to asymmetric allylation though stereoselectivity was around 50% ee. Thus, the hidden aspect of the chemoselective nature of protected hydroxyacetone-derived enolate generated under thermodynamically controlled conditions has opened a new avenue for two-directional elaboration of hydroxyacetone that should be potentially useful in organic synthesis.

Acetone↗

PubMed2006

Anisotropic interaction and stereoreactivity in a chemi-ionization process of OCS by collision with He*(2(3)S) metastable atoms.

Ionic-state-resolved collision energy dependence of Penning ionization cross sections for OCS with He*(2(3)S) metastable atoms was measured in a wide collision energy range from 20 to 350 meV. Anisotropic interaction potential for the OCS-He*(2(3)S) system was obtained by comparison of the experimental data with classical trajectory simulations. It has been found that attractive potential wells around the O and S atoms are clearly different in their directions. Around the O atom, the collinear approach is preferred (the well depth is ca. 90 meV), while the perpendicular approach is favored around the S atom (the well depth is ca. 40 meV). On the basis of the optimized potential energy surface and theoretical simulations, stereo reactivity around the O and S atoms was also investigated. The results were discussed in terms of anisotropy of the potential energy surface and the electron density distribution of molecular orbitals to be ionized.

Journal Article↗

PubMed2006

Global reaction route mapping on potential energy surfaces of formaldehyde, formic acid, and their metal-substituted analogues.

Global reaction route mapping of equilibrium structures, transition structures, and their connections on potential energy surface (PES) has been done for MCHO (M = H, Li, Na, Al, Cu) and HCO2M (M = H, Li). A one-after-another technique based on the scaled hypersphere search method has been successfully applied to exploring unknown chemical structures, transition structures, and reaction pathways for organometallic systems. Upon metal substitution, considerable changes of stable structures, reaction pathways, and relative heights of transition structures have been discovered, though some features are similar among the analogues. Al and Cu atoms were found to behave as very strong scissors to cut the CO double bond in MCHO. Energy profiles of the CO insertion into Li-H and Li-CH3 bonds were found to be very similar, especially around the structures where the Li atom is not directly connected with the methyl group, which indicates little effects of alkyl substitution on the reaction route topology.

Journal Article↗

PubMed2006

Conversion pathways between a fullerene and a ring among C(20) clusters by a sphere contracting walk method: Remarkable difference in local potential energy landscapes around the fullerene and the ring.

Conversion pathways from a fullerene to a ring and vice versa among C(20) clusters have been explored. A new technique has been developed for discovering multistep reaction pathways, which can be searched by finding constrained energy minima on spheres whose surfaces are contracting from the starting point to the terminal. Local landscapes that appeared on the pathways were found to be considerably different around the fullerene and the ring, from which one can make a new interpretation for no generation of the C(20) fullerene in laser vaporization of graphite.

Journal Article↗

PubMed2006

Synthesis of bis(azafulvene)s by dehydration of hydroxymethylpyrrole derivatives.

Bis(azafulvene) was isolated in 55% yield by the reaction of 4 equivalents of phenyllithium with 5,5'-diformyl-3,3',4,4'-tetraethyl-2,2'-bipyrrole followed by quenching with acetic anhydride. Unstable bis(azafulvene)s were obtained in much higher yields by dehydrating 5,5'-bis(hydroxymethyl) derivatives of 2,2'-bipyrrole and gem-dimethyl-2,2'-dipyrrylmethane with (Boc)2O-DMAP at room temperature. X-Ray crystallography of two bis(azafulvene)s is reported.

Journal Article↗

PubMed2006

Probing anisotropic interaction potentials of unsaturated hydrocarbons with He*(2 3S) metastable atom: attractive-site preference of sigma-direction in C2H2 and pi-direction in C2H4.

State-resolved collision energy dependence of Penning ionization cross sections of acetylene (C2H2) and ethylene (C2H4) with He*(2 3S) metastable atoms was observed in a wide collision energy range from 20 to 350 meV. A recently developed discharge nozzle source with a liquid N2 circulator was employed for the measurements in the low-energy range from 20 to 80 meV. Based on classical trajectory calculations for the energy dependence of the partial ionization cross sections, anisotropic potential energy surfaces for the present systems were obtained by optimizing ab initio model potentials for the chemically related systems Li+C2H2 and C2H4. In the case of C2H2, the global minimum was found to be located around the H atom along the molecular axis with a well depth of 48 meV (ca. 1.1 kcal/mol). On the other hand, a dominant attractive well with a depth of 62 meV (ca. 1.4 kcal/mol) was found in the piCC electron region of C2H4. These findings were discussed in connection with orbital interactions between molecular orbitals of the target molecules and atomic orbitals of the metastable atom. It is concluded that sigma-type unoccupied molecular orbitals of C2H2 and a piCC-type highest occupied molecular orbital of C2H4 play a significant role for the attractive-site preference of sigma direction in C2H2 and pi direction in C2H4, respectively.

Journal Article↗

PubMed2005

Development of a cooled He*(23S) beam source for measurements of state-resolved collision energy dependence of Penning ionization cross sections: Evidence for a stereospecific attractive well around methyl group in CH3CN.

A low-temperature discharge nozzle source with a liquid-N(2) circulator for He*(2(3)S) metastable atoms has been developed in order to obtain the state-resolved collision energy dependence of Penning ionization cross sections in a low collision energy range from 20 to 80 meV. By controlling the discharge condition, we have made it possible to measure the collision energy dependence of partial ionization cross sections (CEDPICS) for a well-studied system of CH(3)CN+He*(2(3)S) in a wide energy range from 20 to 350 meV. The anisotropic interaction potential energy surface for the present system was obtained starting from an ab initio model potential via an optimization procedure based on classical trajectory calculations for the observed CEDPICS. A dominant attractive well depth was found to be 423 meV (ca. 10 kcal/mol) at a distance of 3.20 A from the center of mass of CH(3)CN in the N-atom side along the CCN axis. In addition, a weak attractive well (ca. 0.9 kcal/mol) surrounding the methyl group (-CH(3)) has been found and ascribed to the interaction between an unoccupied molecular orbital of CH(3)CN and 2s atomic orbital of He*(2(3)S).

Journal Article↗

PubMed2005

A phase I combination chemotherapy study of biweekly paclitaxel and S-1 administration in patients with advanced gastric cancer.

The aim of the current study was to determine the maximum tolerated dose (MTD) and the dose limiting toxicity (DLT) of a combination of paclitaxel and S-1 in patients with advanced gastric cancer. Fifteen patients were enrolled. The dose for S-1 was set at 80 mg/m2/day (days 1-14), while the dose for paclitaxel increased by 10 mg/m2 for every three patients, with a starting dose of 100 mg/m2 and was given biweekly on day 1 and 15. There was no severe toxicity (grade 4) recorded in patients receiving up to 120 mg/m2 of paclitaxel. Leukopenia/neutrophilia with grade 1 to 3 occurred in six patients up to level 3. At 130 mg/m2 of paclitaxel, grade 4 leukocytopenia and neutropenia events and grade 3 diarrhea developed in one out of three patients. One patient in another group of three patients that were enrolled at level 3, developed grade 4 granulocytopenia with fever (a body temperature higher than 38 degrees C) and grade 3 leukocytopenia. Eight patients, out of a total of 15, showed a partial response, resulting in an objective response rate of 53%. Five patients received gastrectomy. Median survival time was 428 days and the 1 year survival rate was 53%. Biweekly paclitaxel/S-1 combination chemotherapy could be safely used for the treatment of advanced gastric cancer. The recommended doses for a phase II study with paclitaxel and S-1 are 120 mg/m2 and 80 mg/m2, respectively.

Adult↗

PubMed2005

Global investigation on the potential energy surface of CH3CN: application of the scaled hypersphere search method.

An extensive quantum chemical study of the potential energy surface (PES) for all possible isomerization and dissociation reactions of CH3CN is reported at the DFT (B3LYP/6-311++G(d,p)) and CCSD(T)/ cc-pVTZ//B3LYP/6-311++G(d,p) levels of theory. The pathways around the equilibrium structures can be discovered by the scaled hypersphere search (SHS) method, which enables us to make a global analysis of the potential energy surface for a given chemical composition in combination with a downhill-walk algorithm. Seventeen equilibrium structures and 59 interconversion transition states have been found on the singlet PES. The four lowest lying isomers with thermodynamic stability are also kinetically stable with the lowest conversion barriers of 49.69-101.53 kcal/mol at the CCSD(T)/cc-pVTZ//B3LYP/6-311++G(d,p) level, whereas three-membered-ring isomers c-CH2NCH, c-CH2CNH, and c-CHNHCH can be considered as metastable intermediates which can further convert into the low-lying chain-like isomers and higher lying acyclic isomers with the lowest conversion energies of 21.70-59.99 kcal/mol. Thirteen available dissociation channels depending on the different initial isomers have been identified. A prediction can be made for the possible mechanism explaining the migration of a hydrogen atom in competition with the CC bond dissociation. Several new energetically accessible pathways are found to be responsible for the migration of the hydrogen atom. The present results demonstrate that the SHS method is an efficient and powerful technique for global mapping of reaction pathways on PESs.

Acetonitriles↗

PubMed2005

Arthroscopic transtendon repair of partial-thickness articular-side tears of the rotator cuff: anatomical and clinical study.

BACKGROUND: The precise results of arthroscopic transtendon repair of partial-thickness articular-side tears of the rotator cuff remain to be reported. HYPOTHESIS: Arthroscopic transtendon repair is useful in patients with Ellman grade 3 (>6 mm) partial-thickness articular-side tears of the supraspinatus tendon. STUDY DESIGN: Descriptive laboratory study and case series; Level of evidence, 4. METHODS: In 43 cadaveric shoulders (mean age, 80 years; range, 50-97 years), the authors measured the width of the supraspinatus insertion (medial-to-lateral direction) and the distance between the articular cartilage edge and the tendon insertion at a site 10 mm lateral to the anterior margin of the greater tuberosity. A clinical study group of 17 patients (mean age, 42 years; range, 17-51 years) was observed for a mean follow-up of 39 months (range, 25-57 months). University of California at Los Angeles and Japanese Orthopaedic Association shoulder scores and postoperative overhead athletic activities were evaluated. RESULTS: The mean width of the supraspinatus insertion was 9.6 mm (SD, 1.6 mm; range, 7-13 mm; 95% confidence interval, 9.1-10.1 mm; 95% prediction interval, 6.4-12.8 mm). The mean distance between the articular cartilage edge and the tendon insertion was 0.3 mm (range, 0-2 mm). After the procedure, the mean University of California at Los Angeles and Japanese Orthopaedic Association scores significantly improved from 17.3 and 68.4 points to 32.9 and 94.8 points, respectively (P < .01). Rated on the Japanese Orthopaedic Association scale, results were excellent in 14, good in 2, and fair in 1 patient; there were no poor results. Of 6 overhead-throwing athletes, 2 returned to their previous sports at the same level, 3 returned at a lower level, and 1 was unable to return. CONCLUSION: Arthroscopic transtendon repair is a safe, reliable procedure in patients with grade 3 partial-thickness articular-side tears. In the majority of patients, partial tears of more than 6 mm of the supraspinatus tendon thickness involved more than 50% of the entire tendon thickness.

Adolescent↗

PubMed2005

Global mapping of equilibrium and transition structures on potential energy surfaces by the scaled hypersphere search method: applications to ab initio surfaces of formaldehyde and propyne molecules.

Technical details of a new global mapping technique for finding equilibrium (EQ) and transition structures (TS) on potential energy surfaces (PES), the scaled hypersphere search (SHS) method (Ohno, K.; Maeda, S. Chem. Phys. Lett. 2004, 384, 277), are presented. On the basis of a simple principle that reaction pathways are found as anharmonic downward distortions of PES around an EQ point, the reaction pathways can be obtained as energy minima on the scaled hypersphere surface, which would have a constant energy when the potentials are harmonic. Connections of SHS paths between each EQ are very similar to corresponding intrinsic reaction coordinate (IRC) connections. The energy maximum along the SHS path reaches a region in close proximity to the TS of the reaction pathway, and the subsequent geometry optimization from the SHS maximum structure easily converges to the TS. The SHS method, using the one-after-another algorithm connecting EQ and TS, considerably reduces the multidimensional space to be searched to certain limited regions around the pathways connecting each EQ with the neighboring TS. Applications of the SHS method have been made to ab initio surfaces of formaldehyde and propyne molecules to obtain systematically five EQ and nine TS for formaldehyde and seven EQ and 32 TS for propyne.

Journal Article↗

PubMed2005

Sports activity after arthroscopic superior labral repair using suture anchors in overhead-throwing athletes.

PURPOSE: To evaluate the results of arthroscopic repair of type II superior labral anterior posterior lesions of the shoulder in overhead athletes. HYPOTHESIS: Such repair is useful for overhead athletes in terms of postoperative sports activity. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: The study group was composed of 40 patients with a mean age of 24 years (range, 15-38 years); mean follow-up was 41 months (range, 24-58 months). They were divided into an overuse (n=22) and a trauma group (n=18). The authors used 2 suture anchors loaded with a nonabsorbable suture at the 11-o'clock and 1-o'clock positions through the anterosuperior and lateral trans-rotator cuff portal. A modified Rowe score and postoperative athletic activities were evaluated. RESULTS: After arthroscopic repair, mean modified Rowe scores improved from 27.5 to 92.1 points (P<.0001). Rated on this scale, the results were excellent in 30 (75%), good in 6 (15%), and fair in 4 (10%) athletes; there were no poor results. Satisfactory outcomes were achieved in 36 (90%) of these patients; 30 (75%) experienced a return to the preinjury level. The complete return rate of baseball players in the overuse group was lower than that of other overhead athletes in the trauma group. CONCLUSION: Arthroscopic superior labral repair is a safe and reliable procedure in overhead athletes.

Adolescent↗

PubMed2005

Penning ionization electron spectroscopy of C6H6 by collision with He*(2 3 S) metastable atoms and classical trajectory calculations: optimization of ab initio model potentials.

The potential energy surface of benzene (C(6)H(6)) with a He*(2(3)S) atom was obtained by comparison of experimental data in collision-energy-resolved two-dimensional Penning ionization electron spectroscopy with classical trajectory calculations. The ab initio model interaction potentials for C(6)H(6)+He*(2(3)S) were successfully optimized by the overlap expansion method; the model potentials were effectively modified by correction terms proportional to the overlap integrals between orbitals of the interacting system, C(6)H(6) and He*(2(3)S). Classical trajectory calculations with optimized potentials gave excellent agreement with the observed collision-energy dependence of partial ionization cross sections. Important contributions to corrections were found to be due to interactions between unoccupied molecular orbitals and the He*2s orbital. A C(6)H(6) molecule attracts a He*(2(3)S) atom widely at the region where pi electrons distribute, and the interaction of -80 meV (ca. -1.8 kcal/mol) just cover the carbon hexagon. The binding energy of a C(6)H(6) molecule and a He* atom was 107 meV at a distance of 2.40 A on the sixfold axis from the center of a C(6)H(6) molecule, which is similar to that of C(6)H(6)+Li and is much larger than those of the C(6)H(6)+[He,Ne,Ar] systems.

Journal Article↗

PubMed2005

A comparison of arthroscopic and open rotator cuff repair.

PURPOSE: The purpose of this study was to compare the results of all-arthroscopic repair of full-thickness rotator cuff tears including massive tear with those of open repair. TYPE OF STUDY: Nonrandomized control study. METHODS: We evaluated 100 consecutive patients (100 shoulders) who were treated for full-thickness rotator cuff tears either by all-arthroscopic (50 patients) or open repair (50 patients). The mean age was 57 years (range, 24 to 78 years). The mean follow-up period was 49 months (range, 25 to 83 months). Of all the patients, 7 had a small tear, 63 a medium tear, 17 a large tear, and 13 a massive tear; in the arthroscopic group, 5 had a small tear, 28 a medium tear, 9 a large tear, and 8 a massive tear. The results of the arthroscopic and open groups were compared using the shoulder rating scale of the University of California at Los Angeles (UCLA) and the Japanese Orthopaedic Association (JOA). RESULTS: The 2 groups were statistically similar in terms of age, gender, trauma incidence, tear size, duration of symptoms, and preoperative shoulder scores. The UCLA and JOA scores improved significantly in both groups postoperatively. Outcomes and the postoperative UCLA and JOA scores were not significantly different between the 2 groups. The postoperative UCLA and JOA scores in patients with a large-to-massive tear were significantly lower than those with a small-to-medium tear, but outcomes were not statistically different between the arthroscopic and open groups depending on the tear size. The percentage of satisfactory results of arthroscopic and open repair for small-to-medium tears was 97.0% and 94.6%, respectively. Those of arthroscopic and open repair for large-to-massive tears was 82.4% and 76.9%, respectively. CONCLUSIONS: Arthroscopic repair of small-to-massive tears had outcomes equivalent to those of open repair. Outcomes in patients with large-to-massive tears were inferior to those in patients with small-to-medium tears, regardless of repair method. LEVEL OF EVIDENCE: Level III, case-control study.

Activities of Daily Living↗

PubMed2004

Increased plasma lipid-poor apolipoprotein A-I in patients with coronary artery disease.

BACKGROUND: Pre-beta 1-HDL participates in a cyclic process involved in the retrieval of cholesterol from peripheral tissues. Although pre-beta 1-HDL can be measured by two-dimensional electrophoresis or crossed immunoelectrophoresis, these methods are time-consuming and require technical expertise. In this study, we separated plasma lipid-poor apolipoprotein A-I (apo A-I) by high-performance size-exclusion chromatography. METHODS: We measured plasma lipid-poor apo A-I in 20 male patients with coronary artery disease [CAD; mean (SD) age, 64.0 (18) years] and 15 male controls [54.7 (17) years] and in 7 female CAD patients [70.3 (7.7) years] and 9 female controls [65.1 (4.7) years]. RESULTS: Lipid-poor apo A-I was most stable when stored at -80 degrees C in the presence of aprotinin (final concentration, 50 kIU/L). The lipid-poor apo A-I concentration decreased during incubation at 37 degrees C, and this was not prevented by the addition of 2 mmol/L of the lecithin:cholesterol acyltransferase (LCAT) inhibitor 5,5'-dithiobis(2-nitrobenzoic acid). Lipid-poor apo A-I was significantly higher in CAD patients than in controls [38.3 (7.9) mg/L for male CAD patients vs 29.3 (7.3) mg/L for male controls; 43.3 (11) mg/L for female CAD patients vs 27.1 (7.4) mg/L for female controls (P <0.01 for both)]. There were no significant differences in LCAT activity or cholesteryl ester transfer protein (CETP) concentration between patients and controls. Moreover, the plasma lipid-poor apo A-I concentration was not significantly correlated with LCAT or CETP activities. CONCLUSIONS: Although the production of lipid-poor apo A-I in plasma is not fully understood, our results indicate that lipid-poor apo A-I could be used as a marker for arteriosclerosis and demonstrate that it is not identical to the pre-beta1-HDL measured by other methods.

Aged↗

PubMed2004

Changes in quinolinic acid production and its related enzymes following D-galactosamine and lipopolysaccharide-induced hepatic injury.

Increases in quinolinic acid (QUIN), a neurotoxic L-tryptophan metabolite, have been observed in human serum and cerebrospinal fluid and in animal models of severe hepatic injury. The aim of this study was to evaluate the changes in QUIN accumulation and its related enzymes after acute hepatic injury induced by D-galactosamine and endotoxin. Gerbils were given an intraperitoneal injection of pyrogen-free saline alone as control, lipopolysaccharide (LPS) alone (150 ng/kg), D-galactosamine alone (500 mg/kg) or a combination of D-galactosamine with LPS. Concentrations of QUIN, its related metabolites, and related enzyme activities were determined. D-Galactosamine treatment significantly decreased activities of hepatic aminocarboxymuconate-semialdehyde decarboxylase (ACMSDase) resulting in increased QUIN concentrations in serum and tissues. The magnitude of QUIN responses was markedly increased by endotoxin due to the increased availability of L-kynurenine, a rate-limiting substrate for QUIN synthesis. Further, infiltration of monocytes/macrophages, which is a possible major source of QUIN production in the liver, was shown by immunohistochemistry after hepatic injury induced by D-galactosamine and endotoxin. Increased serum QUIN concentrations are probably due to the increased substrate availability and the decreased activity of aminocarboxymuconate-semialdehyde decarboxylase in the liver, accompanying the increased monocyte/macrophage infiltration into the liver after hepatic injury.

Animals↗

PubMed2004

An overlap expansion method for improving ab initio model potentials: anisotropic intermolecular potentials of N2, CO, and C2H2 with He*(2(3)S).

An overlap expansion method is proposed for improving ab initio model potentials. Correction terms are expanded in terms of overlap integrals between orbitals of the interacting system. The method is used to improve ab initio model potentials for N2+He*(2(3)S), CO+He*(2(3)S), and C2H2+He*(2(3)S). Physical meanings of the optimization are elucidated in terms of target orbitals. Correction terms are found to be dominated by the components of HOMO, LUMO, next-HOMO, and next-LUMO on the target molecule. The present overlap expansion method using a limited number of correction terms related to frontier orbitals provides an efficient and intuitive approach for construction of highly anisotropic intermolecular interaction potentials.

Journal Article↗

PubMed2004

Normal variations of the glenohumeral ligament complex: an anatomic study for arthroscopic Bankart repair.

PURPOSE: The purpose of this study was to evaluate the prevalence and morphologic characteristics of normal variations in the glenohumeral ligament complex (GHLC). TYPE OF STUDY: Anatomic study in cadavers. METHODS: We investigated 84 cadaver shoulders and recorded visualization of the superior glenohumeral ligament (SGHL), middle glenohumeral ligament (MGHL), and anterior band of the inferior glenohumeral ligament (AIGHL). In cases with an AIGHL, we noted the location of its origin with respect to the anterior glenoid in terms of a clock face as in a right shoulder. If an MGHL was present, the site of its glenoid attachment was recorded. The presence of a cord-like MGHL, the Buford complex, and a sublabral foramen was also investigated. RESULTS: Of these, 79 (94.1%) manifested an SGHL, 53 (63.1%) an MGHL, and 76 (90.5%) an AIGHL. The AIGHL originated in an area located between the 2- and 5-o'clock position; in 11 (14.5%), the origin was at the 2-o'clock position; in 49 (64.5%) at the 3-o'clock position; in 11 (14.5%), the 4-o'clock position; and in 5 (6.5%) at the 5-o'clock position. Two common variations in the attachment of the MGHL were seen; 30 of 53 MGHL (56.6%) originated from the labrum separate from the origin of the SGHL, and 23 (43.4%) from the labrum at the origin of the SGHL. Of the 84 specimens, 15 (17.9%) manifested a cord-like MGHL, and one (1.2%) the Buford complex. None of the specimens had a sublabral foramen, a finding that requires further investigation. CONCLUSIONS: Our results suggest that the Buford complex is a rare variant of the GHLC, and the cord-like MGHL appears to be a relatively common normal variant. CLINICAL RELEVANCE: The present study provides useful information concerning normal variations of the GHLC to arthroscopists considering Bankart repair.

Aged↗