BACKGROUND Alveolar macrophages from patients with sarcoidosis express increased quantities of HLA-DR during activation. Because silver staining has been described as a sensitive indicator of cellular activity a study was performed to examine whether it relates to HLA-DR antigen expression. METHODS The relation between silver staining patterns of nucleoli and HLA-DR antigen expression was exa...

The objective of this study was to cytogenetically analyze Phractocephalus hemioliopterus comparing the findings with other data to infer relationships among Pimelodidae species. The results revealed a diploid number of 2n = 56 and the karyotype composed of 16 metacentric, 20 submetacentric, 6 subtelocentric and 14 acrocentric chromosomes (FN = 98). The Ag-NORs, 18S rDNA and CMA3 signals were c...

The Nucleolar Organizer Regions (NORs) were first described by Heitz (1931) and McClintock (1934) as weakly stained chromatin regions around which, at the end of telophase, nucleoli are reformed after their disappearance during the mitotic phase of the cell cycle. NORs, located on short arm of acrocentric chromrsomes (Chromosome number 13,14,15,21 and 22) contain ribosomal genes which encode fo...

The aim of the study was an evaluation of the proliferation activity of Central Nervous System tumours by using silver colloid staining of nucleolar organiser regions (AgNORs) and comparing the results with the proliferation activity estimated by using PCNA and Ki-67 antibodies to clarify the clinicopathological significance of this method. The first part of the study describes the results of A...

Characidae is one of the predominant fish groups in the Neotropical region with approximately 30 highly diversified subfamilies, probably not representing a monophyletic group. Three Characidae species from the São Francisco River basin (Três Marias, MG, Brazil) were analyzed: Hasemania nana with 2n=50 chromosomes (8m+42sm), Orthospinus franciscencis with 2n=50 chromosomes (22m+20sm+2st+6a) and...