Absolutely. If you (the OP) are from Europe you may be used to well-defined hiring windows where a job ad closes on date X and after that it doesn't matter if you are a triple-Nobel-prizewinner, you will not be considered.

The US has a much more fluid model in the commercial sector (in fact it is possibly to apply and be hired where no job has been advertised at all). There is nothing dodgy about directly contacting people you had good leads with and mentioning your circumstances have changed, recap anything positive they have said to you previously, and re-attach your resume.

Standard job-seeking advice applies, for example don't go into any details about the previous employer or the fact that you are desperate for a job in the US. Keep it to the minimum facts.