Bermuda-based reinsurer Platinum Underwriters Holdings yesterday said it expects to book $112.4 million in catastrophe losses in its third-quarter results.Some of these losses relate to increases in its loss estimates for catastrophes that occurred in the first half of the year, based primarily on new claims information recently received from clients.Platinum attributed $14.1 million to the effects of Hurricane Irene, which caused extensive flooding and wind damage in the Caribbean and along the east coast of the US in August.The losses are net of retrocessional coverage, reinstatement premiums, taxes and the expected impact of foreign exchange rates.