argyrophilic staining of nucleolar organizer regions (agnor) has been considered to be useful in the diagnosis and prognostic evaluation of different cutaneous tumors. in order to evaluate the role of the agnor technique in discriminating aggressive from non-aggressive basal cell carcinoma (bcc), paraffin-embedded histologic sections from 30 cases of aggressive bcc (bcc2) and 30 cases of non-ag...

nucleolar organizer regions (nor) are defined as nucleolar components containing a set of argyrophilic proteins which are selectively stained by colloidal silver nitrate staining. although studies have shown that the number of nor dots or particles is directly related to the rapidity of cell proliferation in cancer cells, prognostic or diagnostic value of nor remains controversial. the aim of t...

background: tuberculosis continues to be a serious public health problem causing nearly three million deaths per year all over the world. despite major improvement in diagnosis, it is not possible to control the disease in the absence of surveillance treatment, and follow-up programs. objectives: this research was designed to study the frequency of mycobacterium tuberculosis among specimens ref...

The incorporation of thymidine in Novikoff hepatoma cells and Ehrlich ascites cells was severely and irreversibly inhibited by the polyenic antibiotics filipin and lucensomycin, known for their action on phospholipid-cholesterol membranes. No inhibition could be shown on regenerating liver cells or on acellular preparations from tumor cells. Despite the well-known site of action of these antibi...

herpetosiphon giganteus is a filamentous gliding bacterium. gliding motility is the movement of the cells over surfaces without the aid of flagella. the mechanism responsible for bacterial gliding motility has not been known and there are only a few data on herpetosiphon giganteus. the aim of this study was to observe the ultrastructure and negative staining of isolated strains of herpetosiphon...

The mechanism of cholera toxin (CT) internalization has been investigated using Caco-2 cells transfected with caveolin to induce formation of caveolae, HeLa cells with inducible synthesis of mutant dynamin (K44A) and BHK cells in which antisense mRNA to clathrin heavy chain can be induced. Here we show that endocytosis and the ability of CT to increase the level of cAMP were unaltered in caveol...

Tubulointerstitial fibrosis is characterized by tubular atrophy with basement membrane thickening and accumulation of interstitial extracellular matrix. Decreased matrix metalloproteinase-2 (MMP-2) activity may promote the process. Although human renal proximal tubular cells are sensitive to oxygen deprivation, it is unknown whether cellular endocytosis induced by hypoxia could alter the activi...