Previous studies demonstrated that the dopamine- and adenosine 3',5'-monophosphate-regulated phosphatase inhibitor known as "DARPP-32" is present in rat, cat, monkey, and human retinas. We have followed up these studies by asking what specific cell subtypes contain DARPP-32. Using a polyclonal antibody directed against a peptide sequence of human DARPP-32, we immunostained adult rat retinas that were either transretinally sectioned or flat mounted and found DARPP-32-like immunoreactivity in some cells of the amacrine cell layer across the entire retinal surface. We report here, based on the shape and spatial distribution of these cells, their staining by an anti-parvalbumin antibody, and their juxtaposition with processes containing tyrosine hydroxylase, that DARPP-32-like immunoreactivity is present in AII amacrine cells of rat retina. These results suggest that the response of AII amacrine cells to dopamine is not mediated as simply as previously supposed.

with 14-, 18-and 20-G biopsy needles. One experienced genitourinary pathologist, unaware of patient identifiers and final pathology results, determined the biopsy histology and tumour grade, based on standard haematoxylin and eosin (H&E) techniques and immunohistochemistry. RESULTSThe final pathological evaluation classified 21 masses (68%) as clear cell renal cell carcinoma (RCC), three (10%) as papillary RCC, three (10%) as chromophobe RCC, three (10%) as oncocytoma and one (3%) as a benign lymphoid infiltrate. The biopsy histology correlated with the final pathology in 29/31 cases (94%) with the 14-G, 30/31 cases (97%) with the 18-G and 25/31 cases (81%) with the 20-G needles. In two cases chromophobe RCC was misdiagnosed with oncocytoma, and vice versa. CONCLUSIONIn this study a minimum of an 18-G biopsy needle was the most accurate in determining the histological diagnosis. Clear cell and papillary RCCs were accurately diagnosed on biopsy using an 18-G, whereas oncocytoma and chromophobe RCC were difficult to differentiate using standard H&E techniques and immunohistochemistry.

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