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Biomedical subjects

Makoto Yasuda

Publications and source records attributed to Makoto Yasuda.

At least 19 recordsLinked to original sources
PubMed2006

Epithelial ion transport of human nasal polyp and paranasal sinus mucosa.

Nasal cavity and paranasal sinus have various functions. However, little information is available on ion transport in these upper airway epithelia. In the present study, we measured the anion secretion and the anion channel activity to characterize the ion transport in epithelial cells prepared from human paranasal sinus mucosa (PSM) and nasal polyp (NP). To estimate the anion secretion and the anion channel activity, we measured the short-circuit current (Isc) and the transepithelial conductance (Gt) sensitive to NPPB (a Cl(-) channel blocker). The NPPB-sensitive Isc in PSM was larger than that in NP, correlating to the NPPB-sensitive Gt (Cl(-) channel activity). Forskolin stably elevated the NPPB-sensitive Isc associated with an increase in the NPPB-sensitive Gt in PSM and NP. UTP transiently stimulated the Isc associated with an elevation of Gt in PSM and NP. The stimulatory action of UTP on Isc and Gt was diminished by application of NPPB but not benzamil in PSM and NP, suggesting that UTP induced the NPPB-sensitive Isc (Cl(-) secretion) and Gt (Cl(-) channel activity). These observations suggest that in human PSM and NP, cAMP stably stimulates anion secretion by activating the Cl(-) (anion) channels, and that UTP just transiently elevates anion secretion via activation of some Cl(-) (anion) channels.

Amiloride↗
PubMed2006

Direct coupling reaction between alcohols and silyl compounds: enhancement of Lewis acidity of Me3SiBr using InCl3.

The combination of InCl3 and Me3SiBr provided an enhanced Lewis acid system that can be used to promote a wide range of direct coupling reactions between alcohols and silyl nucleophiles in non-halogenated solvents, such as hexane or MeCN. The enhanced Lewis acidity of this system was measured by the 13C NMR in terms of the coordination to an alcohol. Moreover, the interaction between Me3SiBr and the In(III) species was revealed by 29Si NMR spectral analysis. Highly chemoselective allylations toward a hydroxyl moiety over ketone and acetoxy ones have been demonstrated.

Journal Article↗
PubMed2006

High chelation control of three contiguous stereogenic centers in the Reformatsky reactions of indium enolates with alpha-hydroxy ketones: unexpected stereochemistry of lactone formation.

[reaction: see text] A boat-type of chelated bicyclic transition state involving highly diastereoselective construction of three contiguous stereogenic centers in the Reformatsky reaction of indium enolates with alpha-alkoxy/hydroxy ketones is proposed. alpha-Hydroxy ketones with indium enolates furnished highly diastereoselective lactones, while alpha-alkoxy ketones gave acyclic esters in moderate selectivities. X-ray structure analyses of key products unequivocally revealed the unexpected stereochemistry of products and the reaction pathway.

Journal Article↗
PubMed2006

Cage-shaped borate esters with enhanced Lewis acidity and catalytic activity.

[structure: see text] A cage shape causes high Lewis acidity and catalytic activity on boron. Borate esters that have cage-shaped ligands have accessible LUMO with lower eigenvalues than normal open-shaped borate esters. A large dihedral angle at C-O-B-O in cage-shaped borate esters induces less overlap between p-orbitals on O and B. The hetero-Diels-Alder reaction is effectively catalyzed by the cage-shaped borate, although the open-shaped borate does not act as a catalyst.

Journal Article↗
PubMed2006

Practical and simple synthesis of substituted quinolines by an HCl-DMSO system on a large scale: remarkable effect of the chloride ion.

[reaction: see text] A variety of substituted quinolines are synthesized from imines and enolizable carbonyl compounds under aerobic conditions, in which only water is a byproduct. In DMSO, a catalytic amount of HCl activates carbonyl compounds quite effectively to give the quinolines. A simple and practical procedure is demonstrated on a large scale.

Chlorides↗
PubMed2006

Primary chemotherapy-associated effect of second-line chemotherapy on survival of patients with advanced ovarian cancer.

BACKGROUND: The current treatment of patients with recurrent ovarian cancer who have received initial platinum- or taxane-based chemotherapy depends on the results of the initial chemotherapy. The purpose of this study was to evaluate how to make the selection of second-line agents for patients with recurrent ovarian carcinoma initially diagnosed as stage II to IV. METHODS: We conducted a retrospective crossover study in patients who received second-line chemotherapy at Jikei University School of Medicine. We evaluated the responses, progression-free survivals, survivals of second-line chemotherapy, and overall survivals after primary surgery for 51 patients. The treatment cohorts were defined as follows: TC1, patients who were given paclitaxel and carboplatin as first-line chemotherapy and who, upon recurrence, were treated with a platinum-based combination as second-line; and TC2, patients who were given a non-taxane-based platinum combination as first-line chemotherapy, followed, at the time of recurrence, with paclitaxel and carboplatin. RESULTS: The response rates of the second-line chemotherapy for the TC1 and TC2 groups were 44% and 25% (P=0.09). The median progression-free survivals of TC1 and TC2 were 12.9 and 6.4 months (P=0.018; hazard ratio [HR], 2.42; 95% confidence interval [CI], 1.16-5.04). The median survivals after second-line chemotherapy for the two groups were 16.8 and 10.4 months (P=0.007; HR, 2.78; 95% CI, 1.33-5.84) and overall survivals after primary surgery were 36.6 and 27.9 months (P=0.007; HR, 2.36; 95% CI, 1.07-5.21). CONCLUSION: The TC1 group demonstrated a significantly better response and extension of progression-free survival, as well as significantly better survival after crossover and overall survival after primary surgery. As this was a retrospective analysis, this effect should be considered as hypothesis-generating and assessed prospectively in other trials comparing these two chemotherapy schedules.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2006

Characterization of mitochondria in cisplatin-resistant human ovarian carcinoma cells.

One of the mechanisms of cisplatin cell cytotoxicity is the mitochondria-associated induction of apoptosis. The morphological or functional change of mitochondria in cisplatin-resistant cells has already been reported. Herein we present additional data describing the mitochondrial genomic and functional changes in cisplatin- resistant cells. Cisplatin increased the level of apoptotic cells in cisplatin-sensitive human ovarian carcinoma OV 2008 and C13 cells by 3.90+/-1.01 (SD; N=3) (p<0.01)-fold and 2.03+/-0.20 (SD; N=3) (p<0.01)-fold compared to the basal apoptotic level. This indicates a lower level induction of apoptosis by 50% in cisplatin-resistant OV 2008/C13 *5.25 variant (C13) cells. In both cell types, cisplatin cytotoxicity is mostly inhibited by the caspase-9 inhibitor as well as the caspase-3 inhibitor, Ac-DEVD-CHO, suggesting that the mitochondrial downstream event was functioning well in both the C13 cells and in OV 2008 cells. Mitochondrial transmembrane potential (DeltaPsim) determined by flow cytometry using DiOC6-stained cells revealed a significant depolarization of C13 cells as compared to OV 2008 cells. Treatment of these cells with cisplatin or hydrogen peroxide induces complete mitochondrial DNA damage in OV 2008 cells, while only partial DNA-destruction is observed in C13 cells, strongly suggesting that mitochondria are resistant to cisplatin and oxidative stress response. Continuous oxygen consumption of these cells monitored by a multi-channel dissolved oxygen meter is 1.70-fold higher in OV 2008 cells than C13 cells and the oxygen consumption was decreased by 30% in C13 cells, suggesting mitochondrial respiratory malfunction in these cells. The hypothesis generated here is that mitochondrial DNA resistance to cisplatin and oxidative stress response might be one of the main characteristics concerning the lower level of apoptosis induced by cisplatin. However, the mechanism by which the mitochondrial DNA encoded molecule is involved in cisplatin resistance remains to be determined.

Apoptosis↗
PubMed2006

[Combined chemotherapy with weekly paclitaxel and carboplatin for recurrent and refractory epithelial ovarian cancer--phase I study].

The current initial standard chemotherapy for advanced ovarian cancer is a regimen with a combination of platinum and taxane. However, the 5-year survival rate remains at 40% or lower, and the recurrence rate is as high as 70-80%. Second-line chemotherapy for recurrent cases has not yet been established. We conducted a phase I study of combined chemotherapy with paclitaxel (TXL) and carboplatin (CBDCA) administered weekly for recurrent and refractory ovarian cancer. The subjects were patients with a histopathologically confirmed diagnosis of malignant epithelial ovarian cancer, with recurrent or refractory disease after the initial chemotherapy. TXL was administered at escalating concentrations up to 60-100 mg/m(2), while the dose of CBDCA was fixed at an AUC of 2. In regard to the dosing schedule, premedication was performed as defined before TXL administration, and TXL and CBDCA were administered, in that order, by intravenous infusion for over at least 1 hour. The 4-week period, including the administration of both drugs on Day 1, 8, and 15, was regarded as one course of treatment. No cases developed grade 4 hematoxicity, but leukopenia and neutropenia occurred. All cases of leukopenia of step 4 and step 5 developed grade 3 leukopenia. Grade 2 thrombocytopenia was one example at a low rate. Non-hematological toxicity included neuropathy, arthralgia and muscle pain, but none of the patients developed grade 3 or 4. The response rate was 41.7% (5/12). The response rate of cases administered over TXL 80 mg was 66.7% (4/6). Based on these results,the following dose schedule was recommended for planning and designing a phase II study in the future: CBDCA AUC 2+TXL 80 mg/m(2) (Days 1, 8, and 15 q 4 weeks).

Adenocarcinoma↗
PubMed2005

In- or In(I)-employed tailoring of the stereogenic centers in the Reformatsky-type reactions of simple ketones, alpha-alkoxy ketones, and beta-keto esters.

[reactions: see text] Comprehensive studies were carried out on efficient In- or In(I)-based diastereoselective Reformatsky-type reactions of simple ketones, alpha-alkoxy ketones, and beta-keto esters. High anti selectivity was established in the addition of the branched alpha-halo ester derivatives to simple ketones using indium metal under THF-refluxing conditions. The stereochemistry undoubtedly indicated that the involvement of a cyclic transition state, formed from the ketone and stereochemically preferred transient E-enolate derived from the branched alpha-halo ester. Next, with the view of tailoring high degree of stereoselection, the concept of chelation-controlled addition of indium enolates was envisioned. In this line, marvelously syn selective additions to alpha-alkoxy ketones and beta-keto esters were established. Interestingly, these diastereoselective additions to alpha-alkoxy ketones and beta-keto esters require either In(I)X or In-InCl3 systems in toluene under ultrasonication, while very poor efficiency and diastereoselectivity were obtained using indium metal or THF as solvent. The stereochemistry of key products was unambiguously determined by the single-crystal X-ray structure analyses. On the basis of the observed astonishing diastereoselectivities due to strong chelation plausibly, a low-valent RIn(I)-type transient spices could be projected as very reactive spices in the Reformatsky-type reactions.

Journal Article↗
PubMed2005

A clinical study of endoscopic sinus surgery for sinusitis in patients with bronchial asthma.

BACKGROUND: An association between bronchial asthma and sinusitis has long been suspected. Our aim is to study the clinical features of chronic sinusitis associated with bronchial asthma as two manifestations of one airway disease. METHODS: We conducted a prospective analysis of the outcome of 88 patients, with or without bronchial asthma, who underwent endoscopic sinus surgery (ESS) for chronic sinusitis. Patients were divided into two groups by the presence or absence of asthma and were evaluated. One surgeon performed the ESS, and the same postoperative treatment was given to both groups. The postoperative outcomes of symptoms and objective findings related to sinusitis were evaluated numerically, with a maximum score of 2 points for each examination item. Twenty-eight patients with asthma symptoms were assessed before and after surgery, using peak flow (liter/second) and medication scores (according to US Food and Drug Administration) to determine whether bronchial asthma was improved by first-time ESS. RESULTS: The outcomes of ESS were significantly worse in the asthma group, especially the endonasal findings. Patients suffering from chronic sinusitis and bronchial asthma showed improvement following ESS in terms of their asthma symptoms, peak flow and medication score. Patients with a good ESS result tended to have the greatest improvement in their asthma. CONCLUSIONS: We conclude that sinusitis and asthma are closely related to each other, acting as two manifestations of one airway disease. We recommend treating cases of sinusitis complicated by asthma as a single disease of the entire respiratory tract.

Adult↗
PubMed2005

Deltamethrin, a pyrethroid insecticide, is a potent inducer for the activity-dependent gene expression of brain-derived neurotrophic factor in neurons.

The mRNA expression of brain-derived neurotrophic factor (BDNF) is controlled in an activity-dependent manner through Ca(2+) influx into neurons. Pyrethroids are widely used insecticides of low acute toxicity in mammals, but their effects on sodium channels are known to lead to hyperexcitation in neuronal cells of insects. In this study, we found that deltamethrin, a type II pyrethroid insecticide, was highly effective in inducing BDNF expression in culture and in the rat brain. Addition of deltamethrin to rat cortical cells in culture markedly increased the expression of BDNF exon III-V mRNA and protein, dependent upon the neuronal activity accompanying the influx of Ca(2+) into neurons and the Ca(2+) influx-dependent phosphorylation of extracellular signal-regulated kinases 1/2. The elevated expression was maintained for at least 48 h, even after deltamethrin was withdrawn from the culture medium. Comparison of the effects of selected pyrethroids on the expression revealed that type II but not type I pyrethroids effectively induced BDNF mRNA expression. In addition, administration of deltamethrin to rats increased the level of BDNF protein in the cerebral cortex and hippocampus. These results indicate that deltamethrin is a potent inducer of BDNF expression in neurons and that it may induce neuronal hyperexcitation if it reaches the brain.

Anesthetics, Local↗
PubMed2005

Reductive cross-aldol reaction using bromoaldehyde and an aldehyde mediated by germanium(II): one-pot, large-scale protocol.

[reaction: see text] The reaction of alpha-bromoaldehyde with aldehyde in the presence of GeCl(2)-dioxane gave the syn-selective cross-aldol equivalent. A catalytic amount of Bu(4)NBr improved the yield and selectivity. The initially formed aldol adduct (beta-germoxyaldehyde) did not suffer from over-reaction. This system enabled an intramolecular aldol reaction to give cyclic compounds effectively. One-pot synthetic methodology including bromination of aldehyde followed by cross-aldol reaction with the second aldehyde was successful on a large-scale.

Journal Article↗
PubMed2005

Identification of essential amino acid residues of the NorM Na+/multidrug antiporter in Vibrio parahaemolyticus.

NorM is a member of the multidrug and toxic compound extrusion (MATE) family and functions as a Na+/multidrug antiporter in Vibrio parahaemolyticus, although the underlying mechanism of the Na+/multidrug antiport is unknown. Acidic amino acid residues Asp32, Glu251, and Asp367 in the transmembrane region of NorM are conserved in one of the clusters of the MATE family. In this study, we investigated the role(s) of acidic amino acid residues Asp32, Glu251, and Asp367 in the transmembrane region of NorM by site-directed mutagenesis. Wild-type NorM and mutant proteins with amino acid replacements D32E (D32 to E), D32N, D32K, E251D, E251Q, D367A, D367E, D367N, and D367K were expressed and localized in the inner membrane of Escherichia coli KAM32 cells, while the mutant proteins with D32A, E251A, and E251K were not. Compared to cells with wild-type NorM, cells with the mutant NorM protein exhibited reduced resistance to kanamycin, norfloxacin, and ethidium bromide, but the NorM D367E mutant was more resistant to ethidium bromide. The NorM mutant D32E, D32N, D32K, D367A, and D367K cells lost the ability to extrude ethidium ions, which was Na+ dependent, and the ability to move Na+, which was evoked by ethidium bromide. Both E251D and D367N mutants decreased Na+-dependent extrusion of ethidium ions, but ethidium bromide-evoked movement of Na+ was retained. In contrast, D367E caused increased transport of ethidium ions and Na+. These results suggest that Asp32, Glu251, and Asp367 are involved in the Na+-dependent drug transport process.

Amino Acid Sequence↗
PubMed2004

In- or in(I)-employed diastereoselective Reformatsky-type reactions with ketones: 1H NMR investigations on the active species.

An efficient In- or In(I)-based stereoselective C-C bond formation is reported; the diastereoselective Reformatsky-type reactions of ketones. The predominant formations of anti isomers, confirmed by the X-ray structure analyses of ester derivatives of respective alcohols 9a(1)() and 13a(1)(), conclusively revealed the stereochemistry of the reaction path. (1)H NMR investigations revealed the formation of two types of alpha-metalated transient species from alpha-halo esters with In or In(I) halides. [reaction: see text]

Journal Article↗