Publications by authors named "Hiroko Ohta"

Purpose: To identify the factors that characterize cycles with empty zona pellucida (EZP).

Methods: Thirty-six oocyte retrieval cycles from which EZP were collected and another 36 cycles from which no EZP was collected were compared. The patients were divided into three groups: those with no EZP collected during any cycle, those with EZP collected during all cycles, and those experiencing cycles both with and without EZP.

View Article and Find Full Text PDF

We have previously reported potent substrate-based pentapeptidic BACE1 inhibitors possessing a hydroxymethylcarbonyl isostere as a substrate transition-state mimic. While these inhibitors exhibited potent activities in enzymatic and cellular assays (KMI-429 in particular inhibited Aβ production in vivo), these inhibitors contained some natural amino acids that seemed to be required to improve enzymatic stability in vivo and permeability across the blood-brain barrier, so as to be practical drug. Recently, we synthesized non-peptidic and small-sized BACE1 inhibitors possessing a heterocyclic scaffold at the P2 position.

View Article and Find Full Text PDF

A 59-year-old male with chronic kidney disease was diagnosed as having advanced gastric cancer(cT2N1P0H1M0), and CPT-11+CDDP therapy was started for him simultaneously with hemodialysis(HD). Serum CDDP concentrations were measured in the 1st course, and free-platinum(f-Pt)showing the anti-tumor effect was found to be eliminated by HD. Serum f-Pt levels, however, re-elevated until 24 hours after HD completion.

View Article and Find Full Text PDF

Recently, we reported potent substrate-based pentapeptidic BACE1 inhibitors possessing a hydroxymethylcarbonyl isostere as a substrate transition-state mimic. Because these inhibitors contained some natural amino acids, we would need to improve their enzymatic stability in vivo and permeability across the blood-brain barrier, so that they become practically useful. Subsequently, non-peptidic and small-sized BACE1 inhibitors possessing a heterocyclic scaffold, 2,6-pyridenedicarboxylic, chelidamic or chelidonic moiety, at the P(2) position were reported.

View Article and Find Full Text PDF

A complex mixture of diverse oligosaccharides related to the carbohydrates in glycoconjugates involved in various biological events is found in animal milk/colostrum and has been challenging targets for separation and structural studies. In the current study, we isolated oligosaccharides having high molecular masses (MW approximately 3800) from the milk samples of bearded and hooded seals and analyzed their structures by off-line normal-phase-high-performance liquid chromatography-matrix-assisted laser desorption/ionization-time-of-flight (NP-HPLC-MALDI-TOF) mass spectrometry (MS) by combination with sequential exoglycosidase digestion. Initially, a mixture of oligosaccharides from the seal milk was reductively aminated with 2-aminobenzoic acid and analyzed by a combination of HPLC and MALDI-TOF MS.

View Article and Find Full Text PDF

Recently, we reported substrate-based beta-secretase (BACE1) inhibitors with a hydroxymethylcarbonyl (HMC) isostere as a substrate transition-state mimic. These inhibitors showed potent BACE1 inhibitory activities (approximately 1.2 nM IC(50)).

View Article and Find Full Text PDF

Labeling of ferrocenecarboaldehyde (Fc-CHO) to immunoglobulin G (IgG) via formation of Schiff-base and its reduction was investigated for construction of an electrochemical probe for miniaturized amperometric flow immunoassay. Approximately eight molecules of Fc-CHO were labeled to IgG and the reversible redox property of ferrocene was observed. Labeling efficiency improved by over three times as compared to the conventional method using ferrocenemonocarboxylic acid (Fc-COOH).

View Article and Find Full Text PDF

We synthesized a temperature-responsive polymer, N-(isopropylacrylamide)-methacrylic acid copolymer, to which poly-l-lysine was introduced. The synthesized polymer as well as the parent polymer showed reversible soluble-insoluble changes in response to temperature changes across the lower critical solution temperature at 32 degree C in an aqueous solution. We found that the polymer efficiently captured acidic bio-macromolecules such as RNA, glycosaminoglycans and mucin-type glycoproteins in biological samples, and the captured molecules were recovered using aqueous NaCl solutions at high concentration.

View Article and Find Full Text PDF

This paper describes an on-chip-type electrochemical flow immunoassay system with a multichanneled matrix column. The multichanneled matrix column was functionally coated with cation-exchange resin and used for separation of proteins. Antihistamine immunoglobulin G (IgG) antibody conjugated with ferrocenemonocarboxylic acid (Fc) was also prepared and used as a novel analytical reagent.

View Article and Find Full Text PDF