Sentence:  For the albumin method , equal volumes of 30 % bovine albumin , sample and 2 % cells suspended in saline were allowed to stand at room temperature for 1 hr and then were centrifuged at <WSD>1000</WSD> rpm for 1 min . 
Meaning of the word marked with <WSD> tags:  denoting a quantity consisting of 1,000 items or units