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Biomedical subjects

Y Chan

Publications and source records attributed to Y Chan.

63 records · Page 4Linked to original sources
PubMed1984

Porcine pancreatic alpha-amylase hydrolysis of hydroxyethylated amylose and specificity of subsite binding.

Hydrolysis of partially hydroxyethylated amylose by porcine pancreatic alpha-amylase gives rise to a number of hydroxyethylated di-, tri-, and tetrasaccharides, as well as larger products. No modified monosaccharides were detected. The structures of the products containing two to four D-glucose residues have been analyzed by chromatographic and enzymatic techniques. In no instance were these oligosaccharides modified in the reducing-end residue. The location of hydroxyethylated glucose residues within the oligosaccharides has been interpreted in terms of the ability of that (hydroxyethyl)glucose to bind productively at each of the five subsites of the enzyme active site. Results indicate that subsite 3, the subsite at which catalytic attack occurs, is especially sensitive to changes in the substrate and that unmodified glucose is required for productive binding at this subsite. Other subsites specifically allow binding of some (hydroxyethyl)glucose isomers, but not others. Hydroxyethylation is permitted at C-2, C-3, and C-6 for residues bound at subsite 1 and is permitted at C-6 and possibly at C-2 and C-3 for residues bound at subsite 5. However, substitution is permitted only at C-3 and C-6 for binding at subsite 2 and at C-2 and C-3 for binding at subsite 4.

Amylose↗
PubMed1982

Stimulating effect of the low dose laser - a new hypothesis.

Increase in the amount of secretary material (interreceptor matrix) surrounding the visual cells was observed after laser treatment. At the same time, an increase in labelled uridine uptake by the pigment epithelium was detected. The increase uptake was highest 4 h after laser treatment.

Animals↗
PubMed1981

[The association of Streptococcus mutans with human dental caries (author's transl)].

To investigate association of Streptococcus mutans with human dental caries, 323 adolescent students of Chung Shan Medical & Dental college were examined for decayed missing filled of tooth (DMFT) and then plaques were taken from their first and second upper molar's approximal surface using sterilized dental floss for S. mutans isolation. The result showed that among the 269 caries-active individuals 246 (94.98%) had detectable S. mutans, whereas among the 64 caries-free individuals only 23 (35.93%) were found positive, which showed significant association between plaque levels of S. mutans and dental caries (p less than 0.0001). Although the value is a little higher than that found in other literatures but has no statistically significant difference.

Adult↗