An immunohistochemical and electron-microscopic study of vascular endothelial cells in vocal fold polyps

Origin and Distribution of Connective Tissue and Pericytes Impacting Vascularization in Brain Metastases With Different Growth Patterns

The impact of growth pattern on the distribution of connective tissue and on the vascularization of brain metastases (40 colon, lung and breast carcinoma samples) was analyzed. Most of the cases showed either a "pushing-type" (18/40, mostly colon and lung carcinomas) or a "papillary-type" (19/40, mostly breast carcinomas) growth pattern. There was a striking difference in the growth pattern and vascularization of colon/lung versus breast carcinoma metastases. Pushing-type brain metastases incorporated fewer vessels and accumulated more collagen in the adjacent brain parenchyma, whereas papillary-type brain metastases incorporated more vessels and accumulated collagen in the center of the tumor. We observed duplication of the PDGFRβ-positive pericyte layer accompanied by an increase in the amount of collagen within the vessel walls. The outer layer of pericytes and the collagen was removed from the vessel by invasive activity of the tumors, which occurred either peri- or intratumorally, depending on the growth pattern of the metastasis. Our findings suggest that pericytes are the main source of the connective tissue in brain metastases. Vascularization and connective tissue accumulation of the brain metastases largely depend on the growth pattern of the tumors.

The effect of smoking and forced use of the voice to development of the vocal polyps

Dysphonia is often caused by polyps which are benign changes of pseudotumors With their presence they are hampering with glotis oclusion Laryngomicroscopy of general and endotracheal anaesthesia has been preformed on all of the patients. Microsurgical technique has been used to remove the polyps. Bioptic material was analyzed in pathohystlogoical laboratory of clinic of pathology in Banjaluka. All of the results were presented through tables and graphic representations. Frequency of polyps through age and sex groups, along with the examination of ethyological factors in emergence of polyps of vocal cords. Results are in accordance with the results of other authors who were involved in similar problematics. Through analysis of our data we percieve that the abuse of voice is part of ethiological factors that lead not only to emergence of vocal fold lesions but as well as other benign changes.

Possible involvement of nitric oxide and peroxynitrite in the pathogenesis of human vocal polyps and nodules

Nitric oxide (NO) is a molecule involved in multiple functions including vasodilatation, neural transmission, immune response and inflammation. However, the role of NO in the pathophysiology of vocal cord diseases is not clear. The present study investigated the possible involvement of NO and its toxic metabolite, peroxynitrite, in the pathogenesis of vocal polyps and nodules. Vocal polyps and nodules were obtained from patients receiving surgery for their conditions. Immunohistochemistry was applied to evaluate the expression of the inducible form of nitric oxide synthase (iNOS) as well as the production of peroxynitrite represented by the formation of its biological footprint, 3-nitrotyrosine (3-NT). Each section was given a score of 0 to 4 according to the labeling intensity seen, with the highest number representing the highest labeling intensity. The results showed that vocal polyp had an average iNOS labeling score of 3.2, which was significantly higher than the value of 1.9 in vocal nodules. The average labeling score of 3-NT was 2.8 in vocal polyps, which was also significantly higher than the value of 1.8 in vocal nodules. There was also a positive correlation between the level of iNOS expression and the extent of 3-NT formation. These results suggest that increased peroxynitrite production, resulting from increased iNOS expression and NO formation, may have an important pathogenic role in these vocal diseases.

Abnormalities in pericytes on blood vessels and endothelial sprouts in tumors

Endothelial cells of tumor vessels have well-documented alterations, but it is less clear whether pericytes on these vessels are abnormal or even absent. Here we report that alpha-smooth muscle actin (alpha-SMA) and desmin-immunoreactive pericytes were present on >97% of blood vessels viewed by confocal microscopy in 100-microm-thick sections of three different spontaneous or implanted tumors in mice. However, the cells had multiple abnormalities. Unlike pericytes on capillaries in normal pancreatic islets, which had desmin but not alpha-SMA immunoreactivity, pericytes on capillary-size vessels in insulinomas in RIP-Tag2 transgenic mice expressed both desmin and alpha-SMA. Furthermore, pericytes in RIP-Tag2 tumors, as well as those in MCa-IV breast carcinomas and Lewis lung carcinomas, had an abnormally loose association with endothelial cells and extended cytoplasmic processes deep into the tumor tissue. alpha-SMA-positive pericytes also covered 73% of endothelial sprouts in RIP-Tag2 tumors and 92% of sprouts in the other tumors. Indeed, pericyte sleeves were significantly longer than the CD31-immunoreactive endothelial cell sprouts themselves in all three types of tumors. All three tumors also contained alpha-SMA-positive myofibroblasts that resembled pericytes but were not associated with blood vessels. We conclude that pericytes are present on most tumor vessels but have multiple abnormalities, including altered expression of marker proteins. In contrast to some previous studies, the almost ubiquitous presence of pericytes on tumor vessels found in the present study may be attributed to our use of both desmin and alpha-SMA as markers and 100-microm-thick tissue sections. The association of pericytes with endothelial sprouts raises the possibility of an involvement in sprout growth or retraction in tumors.