CARLOS PRIETO PLAYS SHOSTAKOVICH. Cello Concerto No. 1; Sonata for cello and piano, Opus 40. Carlos Prieto, cello; Doris Stevenson, piano; Xalapa Symphony conducted by Luis Herrera de la Fuente. Angel-EMI Digital SAM-35087. The shadow of Mstislav Rostropovich looms over anyone who attempts Shostakovich's cello music. Even on a 1720 Stradivarius, Prieto cannot measure up to the sublime standard set by Rostropovich, the composer's long-time friend and collaborator. Nonetheless, Prieto's is an entirely respectable, if somewhat academic, performance. Of the two works, the 1959 Cello Concerto is far superior, though the Mexican musician's lush tone, complacent demeanor and perfect intonation are too pretty for its savage, bleak mood. Orchestral and piano accompaniments are competent.