1. The light fraction of the proteoglycan of bovine nasal cartilage was split by treatment with 0.1m-hydrochloric acid in acetone. The products were separated by gel filtration on 4% agarose and two retarded fractions were detected and isolated. These two fractions were found to have a Stokes radius of 134 and 47 A respectively, as determined by calibration of the column against proteins of known hydrodynamic volumes. 2. The 47 A fraction had a protein content of 4% and a glucosamine/galactosamine ratio 1:23. The 134 A fraction had a protein content of 20% and a glucosamine/galactosamine ratio 1:4.8. 3. The results of the viscometric studies on both fractions suggested that the 134 A fraction alone exhibited the property of undergoing reversible pH-dependent aggregation with a transition point at pH4.9. 4. It was concluded that these fractions could represent subunits of the native cartilage proteoglycan.

Acetone↗

PubMedDate not supplied

Rheumatoid factor induction in the mouse: sex differences and the effect of the sex steroids.

Female CBA mice produced a significantly higher plasma rheumatoid factor (RF) response to Salmonella typhosa lipopolysaccharide than did male mice. The peak level in females was observed on day 5-6 after injection and in males on day 7-8. Elevated RF levels continued to be detected more than 30 days later. A second injection of LPS, 38 days after the first, to assess the secondary response, had no more than an additive effect on plasma RF concentration, although the day of peak response was earlier by two days in both sexes. Administration of oestradiol-17 beta by Silastic implant brought forward the day of peak response by two days in both sexes although it reduced its amplitude considerably. Testosterone had little effect on the peak concentrations achieved in both sexes, but did produce a slower decay in plasma RF level. This investigation indicates that the sex hormones can influence the response to LPS, a polyclonal B cell activator. This may have implications for the sex differences seen in autoimmune diseases.

Animals↗

PubMedDate not supplied

Determination of ochratoxin A by monoclonal antibody-based enzyme immunoassay.

A simple and rapid indirect enzyme-linked immunosorbent assay was developed for the quantitative determination of ochratoxin A in barley after the successful production of a high affinity, specific monoclonal antibody. A rapid sample cleanup was achieved by extracting ochratoxin A from barley with chloroform and partitioning the toxin into bicarbonate buffer; the buffer solution was then added directly to the assay plate and ochratoxin A content was assessed. Recoveries were greater than 85% and detection limits were 5 micrograms ochratoxin A/kg barley.

Antibodies, Monoclonal↗