Updated from 1:49 p.m. EDTDespite analyst speculation and a trickle of earnings, health indices were relatively flat at the start of the week. Amgen ( AMGN) got a nudge Monday after an upgrade to outperform from market perform by Sanford C. Bernstein & Co. Bernstein attributed the upgrade to potential restructuring. "We believe it is now inevitable that Amgen will announce a restructuring and that such an announcement could emerge within the next month, potentially even prior to the September 11 FDA advisory committee review of EPO safety in Chronic Kidney Disease (CKD)," Bernstein analysts said in a report. The stock closed up $1.18, or 2.4%, to $51.26. Speaking of upgrades, ImClone ( IMCL), which named John Johnson CEO last week, was upgraded by Cowen & Co. on Friday to neutral from underperform. ImClone stock continued to rise into this week, closing up $1.41, or 4.5%, to $32.69. ImClone and Amgen are both components of the Nasdaq biotechnology index, which was up 1.87, or 0.2%, to 797.42 on Monday. On the earnings side, Ziopharm Oncology ( ZIOP) posted quarterly results Monday that showed a loss of $6.5 million, or 31 cents a share, compared with a loss of $5.4 million, or 43 cents a share, in the year-ago quarter. Analysts surveyed by Thomson Financial had expected a loss of 27 cents a share.