اصلاح روش GMS براي رنگ آميزي پنوموسيستيس كاريني در نمونه هاي بيوپسي ريه

Correction of GMS method for staining Pneumocystis carini in lung biopsy samples

Aims. This study was to introduce a modified GMS staining for more rapid, more accurate and simpler detection of Pneumocystis carini infection. Materials & Methods. Sprague-Dawley rats were weekly administered methylprednisolone acetate (40 mg/kg) subcutaneously for 8 weeks. Then, their lungs were obtained and paraffinized sections were prepared. The sections subsequently were stained with two common GMS staining and our modified staining method. With lOOOx magnification, the quality of stained sections was evaluated and the number of organisms in 50 microscopic fields were enumerated for each method. Results. Our modified GMS method could make better contrast between organisms and lung tissue. Also, the mean number of countable cysts at each microscopic field in our modified method was 35.6±16.7 that was significantly greater than two current methods (3.5+2.65 and 2+1.86; p<0.0001) Conclusion. Our modified GMS staining method can help to more accurate and more rapid diagnosis of PCP and use of this method is recommended as routine diagnostic procedure for diagnosis of PCP.