The University of Maryland Medical Center will send layoff notices to employees at the end of the month as it looks to cut costs in the wake of federal budget cuts and what it and other state hospitals have called inadequate rate increases. Jeffrey Rivest, president and CEO of the Baltimore hospital, sent an email to managers Tuesday that said individual letters regarding layoffs would be given out June 25, 26 and 27. The number of people who will lose their jobs still is being finalized, said spokeswoman Mary Lynn Carver said. She also said the dates of the layoff notifications could change.