While Fools should generally take the opinion of Wall Street with a grain of salt, it's not a bad idea to take a look at particularly stock-shaking analyst upgrades and downgrades -- just in case their reasoning behind the call makes sense.

What: Shares of ISIS Pharmaceuticals, (NASDAQ:IONS) popped 6% today after Deutsche Bank initiated coverage on the biotechnology company with a buy rating.

So what: Along with the call, analyst Alethia Young planted a price target of $60 on the stock, representing 25% worth of upside to yesterday's close. While contrarians might be turned off by ISIS' massive run-up over the past year, Young's sum-of-the-parts valuation analysis suggests that there's plenty of room for the shares to run.

Now what: According to Deutsche, ISIS' risk/reward trade-off remains particularly attractive. "ISIS is a leading platform biotech company with a technology that can silence genes called antisense. We think the platform has significantly evolved and is validated," noted Young. "We see competitive risks on APOC-3 franchise in '14 but think the downside is manageable ($7-10/sh)." So while ISIS' red-hot and volatile shares might not be suited for conservative investors, less risk-averse Fools might want to look into Deutsche's bull call.