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Biomedical subjects

H D Keiser

Publications and source records attributed to H D Keiser.

26 records · Page 2Linked to original sources
PubMed1979

The effect of contaminant proteases in testicular hyaluronidase preparations on the immunological properties of bovine nasal cartilage proteoglycan.

Commercial testicular hyaluronidase preparations are contaminated by a small amount of protease activity which is partially inhibited by serine-protease inhibitors or pepstatin. These protease inhibitors can be shown by Sepharose gel column chromatography to abolish or reduce hyaluronidase-induced degradation of bovine nasal cartilage proteoglycan subunit without affecting the ability of the enzyme to degrade chondroitin sulfate. In addition, immunodiffusion studies indicate that pretreatment of hyaluronidase with these protease inhibitors reduces or abolishes the ability of the enzyme to produce a second "link-related" immunoprecipitin line upon digestion of link protein-containing proteoglycan fractions. Thus, the enhancement of immune reactivity and the unmasking of an additional antigen noted after digestion of cartilage proteoglycan with testicular hyaluronidase are most likely due to the exposure of additional antigenic sites or the the release of more highly immunoreactive fragments by the contaminant proteases rather than to the action of hyaluronidase itself.

Animals↗
PubMed1977

A comparison of bovine nasal cartilage proteoglycan core protein produced by chondroitinase and hyaluronidase: the possible role of protease contaminants.

The basic subunit of cartilage proteoglycan consists of multiple glycosaminoglycan chains covalently attached to a core protein. It is unclear as to whether there is a single core protein or multiple different core proteins, since previous studies using either chondroitinase or testicular hyaluronidase to enzymatically remove chondroitin sulfate side chains from the proteoglycan subunit have yielded conflicting results. In the present study, a chondroitinase-produced core protein preparation isolated as a single peak on Sepharose gel chromatography was found to contain at least two immunologically distinct components. Hyaluronidase-produced core protein from the same proteoglycan subunit fraction was found to contain multiple components nearly all of which were smaller than the components in the chondroitinase digest. A possible explanation of these findings is that they resulted from proteolytic degradation of the core protein in the course of the enzymatic removal of its chondroitin sulfate. The presence of small amounts of protease contaminants in several commercial chondroitinase and hyaluronidase preparations was detected by an extremely sensitive radioassay. Until proteases can be rigorously excluded from enzyme preparations used to degrade the proteoglycan subunit, it will not be possible to determine whether it consists of a single or several different core proteins.

Animals↗
PubMed1975

The induction of non-specific autoimmune phenomena by radiotherapy.

Induction of autoimmune phenomena by radiotherapy was evaluated with fluorescent antinuclear antibodies (FANA), latex fixation, and C'3 complement. 27 random serum samples obtained prior to radiotherapy revealed only a low C'3 in a patient with Hodgkin's disease and Sjögren's syndrome. 33 random serum samples obtained after radiotherapy revealed 7 positive values (5 FANA, 1 latex fixation, and 1 C'3). The increase in positive values was statistically significant.

Antibodies, Antinuclear↗