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Biomedical subjects

S Shoda

Publications and source records attributed to S Shoda.

5 recordsLinked to original sources
PubMed1995

[Surgical and botulinum toxin treatment in two cases of abnormal retinal correspondence-exotropia with congenital homonymous hemianopsia].

We report 2 unusual cases of congenital occipital hemianopsia associated with abnormal retinal correspondence (ARC)-exotropia. Two Japanese males, 25 and 28 years of age, visited our hospital for surgical correction of manifest exotropia with dissociated vertical deviation and overaction of the superior oblique muscle. Visual field examination demonstrated homonymous hemianopsia with approximately 5 to 10 degrees of macular sparing. Visually evoked potential examination showed small amplitude similar to dissociated vertical deviation patients in all half-field stimulation. Electrooculogram examination demonstrated defective pursuit to the ipsilateral side. Some investigators have speculated that progressive exotropia compensates for homonymous hemianopsia and is a rare contraindication for strabismus surgery. To confirm the deterioration of motor and visual functions before surgery in these patients, we tried injections of botulinum A type toxin into the lateral rectus muscle ipsilateral to the hemianopsia. Contrary to the hypothesis, our patients had no change in their binocular visual fields and visual function. Finally, we performed recession of the lateral rectus muscle, so that both patients were satisfied with their ocular alignment, with no marked change of visual behavior.

Adult↗
PubMed1995

[Pattern-reversal visual evoked potentials dissociated vertical deviation].

We recorded pattern-reversal visual evoked potentials (P-VEP) from dissociated vertical deviation (DVD) patients to evaluate the sensory system abnormalities in DVD. 91 DVD patients with good visual acuity were studied. Normal subjects and horizontal strabismic patients without DVD were compared for evaluation. Transient and steady state P-VEPs were recorded from three EEG electrodes placed on the posterior scalp. Half-field checker-board reversal stimulation was applied to stimulate monocular temporal retina and responses from right and left hemispheres were also compared for evaluation. Paradoxical lateralization was observed in all normal subjects. Abnormal P-VEPs were observed in 4 of 20 (20%) horizontal strabismic patients without DVD when employing the transient stimulation method and in 2 of 8 (25%) when using steady state stimulation. Abnormal P-VEPs were observed in 31 of 67 (46.3%) DVD patients, with the transient stimulation method and in 20 of 25 (80.0%) DVD patients with the steady state stimulation method. The abnormalities were various and diverse. Our observations indicate that DVD patients frequently have an abnormal sensory system detected by P-VEP, and DVD might be a complex and multi-origin condition involving both sensory and motor systems.

Adolescent↗
PubMed1994

Assembly of synthetic cellulose I.

Cellulose microfibrils with an electron diffraction pattern characteristic of crystalline native cellulose I have been assembled abiotically by means of a cellulase-catalyzed polymerization of beta-cellobiosyl fluoride substrate monomer in acetonitrile/acetate buffer. Substantial purification of the Trichoderma viride cellulase enzyme was found to be essential for the formation of the synthetic cellulose I allomorph. Assembly of synthetic cellulose I appears to be a result of a micellar aggregation of the partially purified enzyme and the substrate in an organic/aqueous solvent system favoring the alignment of glucan chains with the same polarity and extended chain conformation, resulting in crystallization to form the metastable cellulose I allomorph.

Acetates↗
PubMed1993

A facile enzymatic synthesis of cellooligosaccharide derivatives using beta-lactosyl fluoride.

A convenient method for the preparation of cellooligosaccharide derivatives has been developed that uses beta-lactosyl fluoride as the glycosyl donor. The reaction consists of the following enzymatic processes; (1) a cellulase-catalyzed regio- and stereo-selective lactosylation of a beta-cellobioside as the glycosyl acceptor, utilizing the transglycosylating ability of an enzyme-substrate complex formed from beta-lactosyl fluoride and cellulase; (2) beta-D-galactosidase-catalyzed regioselective cleavage of the terminal D-galactose unit from the lactosylated product, giving rise to a beta-cellotrioside derivative. A cellotetraoside derivative has successfully been prepared in a stereo- and regio-selective manner by repeating these enzymatic reactions and using the resulting beta-cellotrioside as starting material.

Carbohydrate Conformation↗