Relationship between Lesion Parameters after Radiofrequency Catheter Ablation in Striated Muscles and Parenchymal Tissue.

Background and Objectives: Radiofrequency catheter ablation (RFCA) is a highly successful intervention. By comparing the lesion changes in prostate parenchymal and striated muscle tissues after RFCA with and without cooling, it was possible to assess the correlation between the shape regularity, area, and perimeter of the thermal lesion, and to predict the geometric shape changes of the lesions. Materials and Methods: A standard prostate and striated muscle RFCA procedure was performed on 13 non-purebred dogs in two sessions: no cooling and cooling with 0.1% NaCl solution. Microtome-cut 2-3 µm sections of tissue samples were stained with haematoxylin and eosin and further examined. The quotient formula was employed to evaluate the geometric shape of the damage zones at the ablation site. Results: The extent of injury following RFCA in striated muscle tissue was comparable to that in prostate parenchymal tissue. Regression analysis indicated a strong and positive relationship between area and perimeter in all experimental groups. In the experimental groups of parenchymal tissues with and without cooling, an increase in the area or perimeter of the damage zone corresponded to an increase in the quotient value. A similar tendency was observed in the striated muscle group with cooling. However, in the striated muscle group without cooling, an increase in lesion area or perimeter lowered the quotient value. Standardised regression coefficients demonstrated that in the striated muscle with cooling, the damage zone shape was more determined by area than perimeter. However, in the parenchymal tissue, the perimeter had a more substantial impact on the damage zone shape than the area. Conclusions: The damage area and perimeter have predictive power on the overall shape regularity of damage zone geometry in both striated muscles and parenchymal tissue. This approach is employed to achieve a balance between the need for tumour eradication and the minimisation of ablation-induced complications to healthy tissue.

Effects of normalized summation in the visual illusion of extent.

In the present study, the features of summation of effects caused by contextual distracting dots in the length-matching task (a variant of the filled-space illusion) were investigated. In the first two series of psychophysical experiments, the illusion magnitude was measured as a function of the displacement of distractors (either single or double sets of dots) orthogonally to the main axis of the stimulus. It was demonstrated that with increasing displacement, the illusion smoothly decreases for a single set of distractors, while for two sets, the illusion first increases to a certain maximum value, and then gradually decreases. In the third and fourth series of experiments, magnitude of the illusion was measured as a function of the luminance of one set of distracting dots, while the luminance of the other set was fixed. It has been shown that increasing the luminance until the same value is reached for both sets leads to a monotonous growth in the illusion magnitude; after that, the illusion asymptotically decreases to an almost constant level. The theoretical interpretation of the established functional dependencies was performed using a quantitative model based on the assumption that the illusion may arise due to the weighted summation of the distractor-induced normalized neural activity, which leads to the perceptual mislocalization of terminators of stimulus spatial intervals.

Analysis of Morphological and Morphometric Changes in a Parenchymal Tissue after the Radiofrequency Ablation Procedure.

Background and Objectives: Prostate cancer is on the rise in the European Union, and radiofrequency ablation (RFA) is one of the minimally invasive treatment options used for its treatment. Therefore, the aim of this study was to investigate and analyze the effects of RFA on prostate tissues. Materials and Methods: A standard prostate RFA procedure was performed on 13 non-purebred dogs in three sessions: no cooling (NC), cooling with a 0.1% NaCl solution (C.01), and cooling using a 0.9% NaCl solution (C.09). Microtome-cut 2-3 µm sections of prostate samples were stained with hematoxylin and eosin and further examined. Results: A histopathologic evaluation identified four zones of exposure: direct, application, necrosis, and transitional, as the damage on tissues decreased going further from the ablation site. The areas and perimeters of these zones were calculated, and geometric shapes of ablative lesions were evaluated using the quotient formula. Areas and perimeters of prostate tissue lesions in the NC and C.09 sessions were of similar size, whereas those found in C.01 were statistically significantly smaller. Lesions observed in session C.01 were of the most regular geometric shape, while the most irregular ones were found in session C.09. The shapes of lesions closest to the ablation electrode were the most irregular, becoming more regular the further away from the electrode they were. Conclusions: Prostate RFA leads to tissue damage with distinct morphological zones. Notably, the prostate lesions were the smallest and the most regular in shape after RFA procedures using the 0.1% NaCl cooling solution. It can be argued that smaller ablation sites may result in smaller scars, thus allowing for faster tissue healing if the blood flow and innervation at the ablation site are not compromised.

Neuroprotective properties of anthocyanidin glycosides against H2O2-induced glial cell death are modulated by their different stability and antioxidant activity in vitro.

The neuroprotective effect of several anthocyanins in combination with their stability and antioxidant/pro-oxidant activity has been investigated against H2O2-induced oxidative stress in C6 glial cells. First it was found that delphinidin (Dp) 3-O-glucoside and 3-O-rutinoside were degraded within an hour, and at the same time stimulated the production of H2O2 in the micromolar concentration range. The stability of peonidin, pelargonidin (Pg), malvidin (Mv) and cyanidin (Cy) 3-O-glucosides and Cy 3-O-rutinoside was significantly higher than that of Dp 3-O-glycosides, with Pg3G showing the highest percent recovery over time. Based on these findings and chemical difference (according to the set of functional groups on the B-ring) of tested anthocyanins Cy3G, Mv3G and Pg3G were selected as candidates for the protection of glial cells against H2O2-induced oxidative stress. It was revealed that Cy3G (5-20µM) and Mv3G (10-20µM) but not Pg3G protected glial cells against H2O2-induced necrotic cell death. Moreover, these anthocyanins sustained the glutathione antioxidant defence system. Finally, to the extent of our knowledge we were the first to demonstrate the protective effect of Cy3G on the resting mitochondrial respiration rate in H2O2-affected glial cells. The results suggest that Cy3G, as the most prominent antioxidant among tested anthocyanins, could be a potential adjuvant for the prevention or reduction of necrotic glial cell death during the oxidative stress conditions met in neurodegenerative diseases. However, further elucidation of other possible mechanisms for anthocyanins to protect the nervous system is encouraged.

Histology of human glioblastoma transplanted on chicken chorioallantoic membrane.

Glioblastoma is the most malignant tumor in the range of cerebral astrocytic gliomas. A lot of experimental models are used to evaluate various properties of glioblastoma. Chicken chorioallantoic membrane model is one of them. OBJECTIVE. To evaluate histology and survival of glioblastoma tumors taken immediately from operating theatre and transplanted on chicken chorioallantoic membrane. MATERIALS AND METHODS. Glioblastoma samples obtained from 10 patients were transplanted onto 200 eggs. Overall, we used 15 tumors; only 5 of them were not glioblastomas as it was revealed later. RESULTS. The transplanted tumors survive up to 6 days. Transplants do not survive longer because during embryo's development the nourishing membrane dries. Transplanted glioblastomas exhibited the same features as original glioblastomas - necrosis, endothelium proliferation, cellular polymorphism - while transplanted glioblastomas also showed glial fibrillary acidic protein (GFAP), vimentin, Ki67, S100 protein, neurofilament immunoreactivity, and infiltration of macrophages (CD68) and T cells (CD3(+), CD8(+)). Transplanted glioblastomas did not show any immunoreactivity of p53. Invasion of vessels from the chicken into transplanted tumor is not observed. Chicken erythrocytes did not appear within the transplants, and tumor cells invade chicken tissue at the minimum. CONCLUSION. Our data show that transplanted pieces of glioblastoma survive with all cytological features. The presence of macrophages (marker CD68) and T cells (markers CD3(+) and CD8(+)) can be registered in the transplant. The data revealed that transplanted glioblastoma remains as insulated unit, which survives from nourishment of the chorioallantoic membrane apparently only by diffusion. The features of original tumor-host reaction of the patient remained too.

Effect of Echinacea (Echinacea Purpurea L. Moench) preparations on experimental prostate gland.

This work has investigated the effect of echinacea extract on the weight of prostates in rats as well as on alterations of hystological structure and separate blood cells. This preparation was chosen for investigations due to its possible antiandrogenic effect and good immunostimulating features. Experiments were carried out with three-month old male Wistar rats, divided by six into three different groups. The first group was the control one. The rats of the second group were fed for 30 days with the usual food ration plus 50 mg/kg of echinacea extract. The third group was fed for 60 days in the same way as the second one. Clinical death of rats was caused by sodium phenobarbital, later a cervical dislocation was performed. After weighing the rats their prostates were removed and weighed. Patohystological investigations of the removed organs were carried out. Blood test for Shiling's analysis was taken. The weight of prostates in the first group of rats was 412.0+/-14.93 mg, in the second group - 403.0+/-13.33 mg, and in the third group it was 388.0+/-14.66 mg. Having calculated the proportion between prostates of rats and their body weight it was estimated that in the first group it made 0.125+/-0.009%, in the second group - 0.105+/-0.005%, and in the third group - 0.091+/-0.007%. The percentage of lymphocytes in the first group was 72+/-1.41; in the second group - 73+/-0.81; in the third group - 79+/-1,86. The percentage of segmented neutrophyle in the first group was 23+/-3.31; in the second group - 23+/-2.25; in the third group - 18+/-2.33. Having conducted analysis of the experimental results, a significantly important decrease of prostate weight of investigated rats, an increase in the number of lymphocyte as well as the alterations of hystological structures after using echinacea extract for eight weeks were observed.