Given an abstract, generate a keyword (a noun phrase) that best describes the focus or contribution of the paper. Such keywords can be directly from the given abstract or outside it.
Q: Abstract: Serum from patients with amyotrophic lateral sclerosis (ALS) was tested by immunoblotting for reactivity against three muscle-derived preparations: denervated chick leg muscle extracts, media conditioned by denervated rat hemidiaphragms, and a human muscle extract. For each preparation, multiple bands were present using serum from all patients and controls, and no band was unique to ALS. Against rat muscle-conditioned medium, bands in the 56,000 (56K) molecular weight range were present to an equal degree in ALS and in controls; in addition, different bands near 56K were recognized by serum from different ALS patients. These results fail to confirm a recent report suggesting that anti-56K reactivity is characteristic of ALS.
A:
Adult