Biomedical subjects

T Ushio

Publications and source records attributed to T Ushio.

15 recordsLinked to original sources

PubMed2001

Preferential enrichment: an essential crystal structure.

The crystal structure of (+/-)-[2-[4-(2-hydroxyhexyloxy)phenylcarbamoyl]ethyl]dimethylsulfonium p-chlorobenzenesulfonate [(+/-)-SCC], which failed to effect preferential enrichment due to the chemical modification of the prototype (+/-)-[2-[4-(3-ethoxy-2- hydroxypropoxy)phenylcarbamoyl]ethyl]dimethylsulfonium p-chlorobenzenesulfonate [(+/-)-SC] showing preferential enrichment, has been determined by x-ray crystallographic analysis. The crystalline form of (+/-)-SCC is not a mixed crystal of the two enantiomers, but a racemic compound. In addition, the revised crystal structures of (+/-)-[2-[4-(3-ethoxy-2-hydroxypropoxy)phenylcarbamoyl]ethyl] dimethylsulfonium p-toluenesulfonate [(+/-)-ST] and (+/-)-SC, both of which showed preferential enrichment, are described. The crystal structure of (+/-)-SCC is different from that of (+/-)-SC, but very similar to that of (+/-)-ST. The formation of the crystal phase of the (+/-)-SC type, which can be followed by polymorphic transition to afford the crystal one of (+/-)-ST type if necessary, seems to be essential for successful preferential enrichment.

Journal Article↗

PubMed1999

Chiral resolution of basic drugs by capillary electrophoresis with new glycosaminoglycans.

New glycosaminoglycans, fucose-containing glycosaminoglycan (FGAG) and depolymerized holothurian glycosaminoglycan (DHG), were investigated as chiral additives for the separation of drug enantiomers by capillary electrophoresis. The average molecular masses of FGAG and DHG were estimated to be about 59,000 and 14,000, respectively. A variety of basic drug enantiomers were resolved using 10 mM phosphate buffer, pH 5.0, containing 3% FGAG or DHG. Since chiral recognition properties of FGAG and DHG are different, some drug enantiomers were only separated by using FGAG or DHG. With regard to comparison of chiral recognition abilities of FGAG and DHG with other chiral selectors, tolperisone and eperisone enantiomers were not separated with alpha- or beta-cyclodextrin, or heparin as the chiral additives, but were separated with FGAG and DHG. The results obtained reveal that FGAG and DHG are useful as the chiral selectors for separations of drug enantiomers by CE, and that they could be complementarily used with other chiral additives.

Buffers↗

PubMed1998

Spatio-temporal receptive fields in carp retinal horizontal cells.

1. The dynamics of the receptive fields of retinal horizontal cells were examined by applying a spatio-temporal modulated light signal to the retina. 2. The spatio-temporal receptive fields of both cone- and rod-driven horizontal cells, estimated through cross-correlation between the modulated light signal and the cells' responses, showed their receptive fields (the space-dependent component) to be reduced in size with time. 3. In cone-driven horizontal cells, the reduction in receptive field size was initially small but then rapidly became prominent with time. The time to peak of the time-dependent component of spatio-temporal receptive fields did not depend on the distance from the centre. 4. Application of a small amount of Co2+, an agent blocking the cone-driven horizontal cells' feedback action on cones, or GABA, resulted in a reversal of the time-dependent shrinkage of receptive fields to time-dependent expansion. 5. In rod-driven horizontal cells, the receptive field shrinkage was slow. The time to peak of the time-dependent component decreased with the distance from the centre. 6. Image processing experiments examining the response pattern in the horizontal cell layer (neural image) to a moving square of light showed smudging of the neural image when the time-dependent receptive field expansion was present, while there was essentially no smudging under conditions of receptive field shrinkage.

Animals↗

PubMed1998

Effect of arylthiolated 2,3-dimethoxy-1,4-benzoquinones on respiratory activity and lipid peroxidation in bovine heart mitochondria.

A series of arylthiolated 2,3-dimethoxy-1,4-benzoquinones was synthesized and tested for the effect on the respiratory system and the lipid peroxidation in bovine heart mitochondria (BHM). These quinones showed intense inhibitory activities on the respiratory system in BHM. Their inhibitory activity in the succinate oxidase system was greater than that in the NADH oxidase system. No difference between the difference spectra, with and without these quinones, of the reduced minus oxidized forms of cytochromes (cyt.) suggested that these quinones inhibit at the site after cyt. a+a3 in the respiratory chain. Moreover, these quinones were as efficient as exogenous ubiquinone-10 (UQ-10) for the inhibition of lipid peroxidation. 5- And 5,6-di-arylthio groups on the quinone ring were found to be favorable for inhibition of the respiratory system and lipid peroxidation. Our results suggest that arylthiolated 2,3-dimethoxy-1,4-benzoquinones act as antioxidants by increasing the amount of endogenous reduced UQ-10 in BHM.

Animals↗

PubMed1997

[Lung cancer with a sarcoid-like reaction in the primary tumor].

An 80-year-old woman was admitted to the hospital because of a nodular lesion in the right upper lobe of the lung. Transbronchial biopsy was performed and adenocarcinoma of the lung was confirmed by pathological examination. The tumor was resected by right upper lobectomy and was found to be a moderately differentiated tubular adenocarcinoma. Numerous non-caseating epithelioid cell granulomas were also found intermingled with the cancer cells. Metastasis was apparent in several regional lymph nodes but no granulomatous lesions were found in any lymph node, regardless of metastasis. These findings were compatible with a "sarcoid-like reaction" because there was no clinical evidence of generalized sarcoidosis or pulmonary mycobacterial infection. Although sarcoid-like reactions are occasionally associated with cancer, formation of an epithelioid cell granuloma inside the primary tumor is very rare. All the reported cases of a sarcoid-like reaction within the primary lung tumor so far were with adenocarcinoma. The sarcoid-like reaction may be a local immune response to the cancer cells.

Adenocarcinoma↗

PubMed1996

[Physicochemical properties of suplatast tosilate racemate and enantiomers].

The physicochemical properties of the enantiomer and racemates of suplatast tosilate (ST) were investigated by means of infrared spectroscopy, solid-state 13C CP/MAS NMR spectroscopy, thermal analysis, and X-ray diffraction analysis, and by measuring the solubility and hygroscopy. The infrared and NMR spectra and X-ray diffraction pattern of the enantiomer were distinctly different from those of the racemate. The melting point of the enantiomer was lower than that of the racemate by 5 degrees C, while the solubility of the enantiomer was 1.3 times higher than that of the racemate. The hygroscopic rate of the enantiomer was greater than that of the racemate. These results suggested that ST was classified into a racemic compound crystal. Furthermore, by comparing the relative peak intensity ratios on X-ray diffraction patterns of the crystals with various optical purities prepared by recrystallization, it was found that a mixture of racemic compound crystals and either of racemic mixture crystals or racemic solid solutions was obtained by recrystallization of ST in the content of 0 to 64%ee, while the recrystallization of ST in the content of more than 64%ee led to the formation of racemic mixture crystals or racemic solid solutions.

Anti-Allergic Agents↗

PubMed1994

[A case of Castleman's disease that recurred nine years after initial surgical removal].

Castleman's disease (CD) is a lymphoproliferative disorder with resemblance in histopathology of thymoma. Here we describe a 48-year-old man with bloody sputum and a mass lesion of the right hilum on chest roentgenogram. He had undergone an incomplete surgical removal of a mediastinal tumor nine years earlier, which proved to be CD with characteristics of hyaline-vascular type pathology. The regrown mass lesion as well as the right upper and middle lobes were removed surgically. Histological examination of the tumor specimen revealed characteristics of hyaline-vascular type CD which were nearly identical to those of the tumor removed nine years earlier. Recurrence of CD as observed in the present report is very uncommon, since only 5 cases, including this one, have been reported. We suggest that in CD the primary tumor as well as regional lymph nodes should be completely removed, and the patients should be kept under long-term postoperative observation to check for recurrence.

Castleman Disease↗

PubMed1986