In order to understand the mechanism for maintaining life of animals based on the search of dynamics of bio-molecules, I have developed several sensitive and selective methods for their quantification. Using the methods of derivatization with the developed benzofurazan fluorogenic reagents (4-fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F), ammonium 7-fluoro-2,1,3-benzoxadiazole 4-sulfonate (SBD-F) and etc.) followed by high-performance liquid chromatography (HPLC)—fluorescence detection, a certain kind of biological and clinical importances was demonstrated of chiral bio-molecules (D-amino acids, D-lactic acid and so on), peptides and proteins. The proposed method (derivatization with SBD-F, isolation of the fluorescent proteins by two-dimensional HPLC, enzymatic digestion and identification of the altered proteins by HPLC-mass spectrometry (MS)/MS with database-searching algorithm) for proteomics studies revieled the changed proteins in the islets of Langerhans of the dexamethazone-induced diabetic rats. An importance of catecholamine metabolism on the blood pressure regulation was also suggested by the method of HPLC-chemiluminescence detection of catecholamines and their 3-O-methylmetabolites. A new field of Analytical Chemistry, i.e., Bio-Analytical Chemistry, was also proposed.
Enzyme-catalyzed organic syntheses have enormous potential in the development of environmentally benign processes. In the last two decades, increased efforts have been devoted to making this a reality. However, the utility of the enzymes is generally limited. For example, although the lipases are extensively used for the kinetic resolution or the desymmetrization of alcohols and carboxylic acid derivatives, little is known about their ability to catalyze carbon-carbon bond-forming reactions. In the past several years, we have been engaged in exploiting a next-generation enzymatic synthesis by using the lipases for the construction of carbon skeletons. This review article describes the results. First, the development of a new type of acyl donor, 1-ethoxyvinyl esters (EVEs), that have significant advantages over common acyl donors (e.g., vinyl esters) for lipase-catalyzed esterification reactions. Second, the highly enantioselective desymmetrization of prochiral 1,3-propanediols and meso 1,2-diols using 1-ethoxyvinyl 2-furoate. The application of this technology for the asymmetric syntheses of fredericamycin A analogues and the oxindoles with a chiral, nonracemic quaternary carbon center has been demonstrated. Third, the first lipase-catalyzed domino reaction using EVEs possessing a suitably functionalized acyl moiety is described. The acyl moiety installed during the enzymatic kinetic resolution was used as a part of the constituent structure for the subsequent Diels—Alder reaction to produce optically pure tricyclic compounds with five chiral carbon centers via a one-pot operation. The potential influence of the lipase on the Diels—Alder reaction and the domino process accompanied by the dynamic kinetic resolution are also described.
Novel zirconium-mediated carbon-carbon bond-forming reactions were developed. The allylic, γ-alkoxyallylic, allenyl, and γ,γ-dialkoxyallylic zirconium species can be prepared from corresponding ethers under mild conditions through the addition of a zirconocene-butene complex to the carbon-carbon multiple bond of the ethers and subsequent β-elimination of the alkoxyl group. The γ,γ-dialkoxyallylic zirconium species reacts with carbonyl compounds at the β-position of the zirconium atom like a ketene dialkyl acetal in the presence of stoichiometric amounts of Lewis acid and gave cyclopropane and/or cyclobutane derivatives. Intramolecular reaction of allylic zirconium species with acetal also develops as a ring contraction reaction of carbohydrates and morpholine derivatives. This method is useful for the construction of chiral highly functionalized carbocycles and pyrrolidines. The intramolecular ester transfer reaction through the zirconium-mediated coupling reaction of alkenyl carbamates gave γ-aminobutyric acid derivatives and pyrrolidine-3-carboxylic acids.
Adipocyte differentiation takes place via a complex series of steps. While PPARγ and C/EBPα are known to be master regulators, the events at the earliest stage of adipocyte differentiation are not yet known. In this study, we cloned the genes that are induced at the beginning of the differentiation of 3T3-L1 preadipocyte cells. Of 102 clones obtained, only several clones were already reported as genes that are expressed differentially during adipocyte development. The expression of TCL/TC10βL (TC10-like/TC10βLong) and RGS2 (regulators of G protein signaling 2) genes isolated here rapidly increased after the addition of inducers (insulin, dexamethasone, 3-isobutyl-1-methylxanthine, fetal bovine serum[FBS]). Further, the antisense TCL/TC10βL inhibited the adipogenesis of mouse 3T3-L1 preadipocyte cells, prevented cytoplasmic triglyceride accumulation, and decreased the expression of PPARγ and C/EBPα. Moreover, the constitutive overexpression of TCL/TC10βL or RGS2 in the mouse fibroblast cell line NIH-3T3 results in efficient adipocyte conversion when stimulated with 10% FBS, insulin, 3-isobutyl-1-methylxanthine, dexamethasone, and PPARγ ligand BRL49653. These results strongly suggest that TCL/TC10βL and RGS2 have crucial roles in the program of adipocyte differentiation, probably linked to the PPARγ pathway. Using a subtraction protocol, the genes specifically regulated by TCL/TC10βL were also isolated. The expression pattern of some was similar to TCL/TC10βL expression in adipogenesis, suggesting that these genes are regulated by TCL/TC10βL.
A successful development of therapeutic proteins requires a formulation optimal for long-term storage of the proteins. During storage and shipment, proteins are subjected to multiple stresses. Here we show that ciliary neurotrophic factor (CNTF) readily aggregates upon exposure to mechanical stress such as agitation and elevated temperature at 37°C. Sucrose and lysine or arginine protect CNTF from heat stress, while detergents such as Tween20 and organic solvents such as propylene glycol (PG) are effective against agitation. Combination of the amino acids and PG protected the protein from both stresses. The results suggest the importance of combining additives, against multiple stresses, which may have negative as well as positive influence individually against one particular stress.
Twelve N-caffeoylamino acids and N-cinnamoylamino acids were synthesized and their vasorelaxation activity against norepinephrine (NE)-induced contraction of rat aorta was examined. The following structure-activity relationships were found. 1) On the benzene ring, the caffeoyl structure is effective for vasorelaxation, while the cinnamoyl structure reduced vasorelaxation activity. 2) Four to six carbons are more effective as the carbon chain connecting the acylamino and carboxyl terminal groups. N-Caffeoyl-β-alanine and N-caffeoyltranexamic acid were used to investigate the action mechanism of vasorelaxing activities. It is believed that these compounds antagonize NE-induced vasocontraction by inhibiting receptor-operated calcium channels.
We conducted an investigation to determine whether the visual analogue scale (VAS) method could be utilized in evaluating the lectures and pharmacy experience of the Division of Pharmacy and Health Sciences, Graduate School of Natural Science and Technology, Kanazawa University. Graduate students who had finished the 1-year pharmacy experience at the Kanazawa University Hospital were asked to make a self-evaluation of the understanding/attainment of lectures and experience in the course. Since the experience was carried out as a one-student-to-one-pharmacist system, the preceptors (pharmacists) were also asked to evaluate their corresponding students. When evaluating the necessity of the lectures, students tended to feel that the medical science- or pharmacotherapy-related subjects were important and those of social sciences were less important. These results suggest the need to review the contents of the lectures to enhance the interests of the students in the latter. By comparing the extent of understanding of each lecture before and after pharmacy experience, it was found that students had a better understanding of the lectures through their experience. In most results from the answers in pharmacy experience, students also scored themselves higher than their preceptors. Therefore comparisons of evaluation may provide more objective results in pharmacy experience. It was demonstrated that utilization of the VAS method and comparing the data are very useful in evaluating not only students' understanding/attainment but also the importance and usefulness of lectures and pharmacy experience in an objective way.
In order to complete TDM manual for pirmenol in Sapporo Medical Center NTT East, we developed HPLC method and pretreatment procedure for pirmenol samples obtained from patients. Serum (250 μl) was alkalinized and pirmenol was extracted into n-hexane, and then the drug was again extracted into an acidic solvent, 0.044 M KH2PO4 (pH 2.6) including 0.5% triethylamine. The aqueous extract was used for quantitative determination of the drug by HPLC. The mobile phase consisted of the above acidic solvent-acetonitrile (5:1, v/v) was delivered at 45°C with a flow rate of 1 ml/min through a 4.6 mm×25 cm ODS-3, a reversed-phase column. Detection of pirmenol and the internal standard (disopyramide) was achieved at 263 nm. Pirmenol and disopyramide was eluted at 5 and 11 min, respectively. Assay limit (25 ng/ml) and accuracy of the analytical method were satisfactory for TDM of pirmenol. During the HPLC analysis of patient samples, no substances that interfered with pirmenol detection were found. It was shown that 1) hemolysis did not affect pirmenol assay at all, 2) pirmenol was stable in the blood samples for at least 24 h even if they were stood at room temperature, and 3) pirmenol was stable for at least 3 days in frozen serum but there significant decrease was observed in pirmenol concentration after 7 days.