1025
Whole blood serotonin levels were investigated in a control group ( n = 35 ) and in a group of chronic renal failure patients ( n = 127 ) on various treatment regimen i . e . conservative treatment ( n = 39 ) , maintenance haemodialysis ( n = 35 ) and after renal transplantation ( n = 53 ) .
 None
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: GENE 
Text: {0} 
Answer:
 None