Astroglial differentiation of fibronectin­positive human "glia-like" cells.

OBJECTIVES: Fibronectin (Fn) is a glycoprotein of extracellular matrix produced by a variety of mesenchymal and neoplastic cell types. BACKGROUND: In adult brain tissue, Fn is restricted to blood vessels. However, adult human brain cultures are almost entirely comprised of flat or spindle­shaped Fn-positive cells usually referred to as "glia-like" cells. Since Fn is primarily present in fibroblasts, these cultures may be considered to be of non-glial origin. METHODS: Cells gained by long-term culturing of adult human brain tissue derived from brain biopsies obtained from 12 patients with non-malignant diagnoses were examined by immunofluorescence methods. RESULTS: Primary cultures contained GFAP-/Vim+/Fn+ "glia-like" cells (95-98 %) and GFAP+/Vim+/Fn- astrocytes (0.1 %) which disappeared by passage number 3. The formation of cell processes and enlargement of cell bodies was observed in 9 of 12 cultures with decreased cell growth during passages 12 to 17. It is remarkable that during this period, all "glia-like" cells became GFAP+/Vim+/Fn+. CONCLUSION: Herein, we confirm our previously published hypothesis about the origin of adult human "glia-like" cells, which we consider to be precursor cells scattered through the brain cortex and subcortical white matter. Cultures were comprised entirely of GFAP-/Fn+ "glia-like" cells and showed morphological and immunochemical astroglial differentiation with spontaneously decelerated growth during prolonged passaging. We propose that the adult human brain tissue contains a "dormant population" of undefined glial precursor cells. Under culture, these cells show to have a high proliferative capacity and different stages of cell dedifferentiation (Fig. 2, Ref. 21).

Impact of radiotherapy on laryngeal intrinsic muscles.

Ionizing radiation as a cancer therapy is associated with a variety of undesirable side effects. Consequently, radiotherapy can negatively affect neuromuscular function. Clinical observations have identified problems with swallowing and voice function. Our study aims to evaluate the impact of radiotherapy on laryngeal soft tissues using image analysis to quantify its effect on the structure of the vocalis and thyroarytenoid muscles. Case control study, retrospective analysis. We collected total laryngectomy specimens from six patients with persistent or recurrent cancer who had received preoperative radiotherapy (60-66 Gy). The control group consisted of total laryngectomy specimens from six patients who underwent surgery as primary treatment. Sampling of the specimens only included non-cancerous laryngeal tissue. Laryngeal histological slices were evaluated using digital morphometric analysis system. Percentage of fibrosis and density of muscle fibers within the thyroarytenoid muscle were evaluated in both groups. We found no significant quantitative differences in muscle fibrosis (7.92% vs. 7.52%, P > 0.1). Changes were rather qualitative and included changes in the organization of the muscular fibers. A significant reduction in muscle fibers, however, was observed in the samples from irradiated larynges (66.45% vs. 42.03%, P < 0.01). Our analysis suggests that radiotherapy is responsible for a significant reduction in muscle fibers in the thyroarytenoid muscle and that these changes occur during treatment or relatively early after its completion. Loss of muscle mass after irradiation correlates with clinical observations of muscle weakness and decreased function in patients who undergo radiotherapy.

Expression of constitutive nitric oxide synthase isoforms in varicose vein wall; preliminary results.

There are conflicting findings in literature about the structural changes of the primary varicose veins. NO (a potent vasodilatator) is synthesized by nitric oxide synthase (NOS). From 3 known NOS isoforms the two are constitutional: eNOS (endothelial NOS) and nNOS (neuronal NOS). 10 varicose and 10 control vein samples were processed by standard light microscopy and immuno-histochemica techniques using rabbit polyclonal antibodies against eNOS and nNOS. Antibodies expression was evaluated semiquantitatively and proved morphometrically by 2D-image analysis. total area of NOS isoforms expressions was determined by color analysis and color digital subtraction. The results showed discontinuous and significantly lower expression of both NOS isoforms the in the tunica media of varicose veins compared with the control group. For the statistical analysis the unpaired t-test was used. Our results suppose lower NO levels in varicose vein wall, deducing that varicose dilatation is due to other mechanism, and they contradict the results of previously published similar works.

Mast cell infiltration in the wall of varicose veins.

Varicose veins of the lower extremities are abnormally dilated, tortuous and elongated. The exact cause of vein dilatation has still not been established. Mast cells produce, store and release various types of vasoactive compounds (histamine, tryptase, prostaglandins, leukotrienes, and cytokines). Histamine enhances local vasopermeability and smooth muscle cell proliferation, leading to thickening of the intima. Tryptase can contribute to local vascular injury and subsequent weakness of the vascular wall causing varix formation. The aim of the present study was the comparison of mast cell infiltration in the wall of varicose and non-varicose veins. The mean mast cell density in the wall of varicose veins was 0.86 mast cell per mm2 and in healthy non-dilated vein walls, density was 1.23 mast cell per mm2. This difference was not statistically significant, therefore we could not confirm our hypothesis. Nevertheless, we suggest that mast cells could play an important role in the development of varices and the factor released by the mast cells should be further examined.