Faculty Bibliography

Lignin, the structural polymer of the plant cell walls, is produced by free radical polymerization of phenolic alcohols, catalyzed by different peroxidases. The mechanism and the structural organization of lignin in the cell have not been completely understood. In this study we applied fractal analysis to images of lignin polymer obtained using scanning tunneling microscope. The analysis showed the regularity of the polymer at different levels of organization. According to the results obtained, at the 95% confidence level, there is no significant difference in the fractal dimension between images representing different organizational levels of lignin. In other words, lignin produced in in vitro conditions has fractal structural organization and, consequently the polymer can be expected to be regular in in vivo conditions. The value of the fractal dimension 1.929 +/- 0.021 is in good agreement with the theoretically predicted value for polyaddition and polycondensation mechanism of polymerization. The mechanism of in vivo lignin synthesis is discussed in terms of various experimental and theoretical evidences. In this paper, we could show that fractal analysis of the lignin polymer is a useful complementary approach to the experimental data collection in structural and phenomenological studies

INTRODUCTION: Renal cell carcinoma, also known as renal adenocarcinoma is the most common primary renal malignancy. Protean and often nonspecific clinical manifestations of renal carcinoma have lead to its description as the 'great imitator' in medicine. Because of the importance of early diagnosis and lack of specific clinical features, imaging has a vital role in its diagnosis. Since the only successful curative treatment of renal adenocarcinoma is surgery, preoperative evaluation of the extent of the disease may play an important role for determining surgical approach and tumor resectability. Over the past decade, computerized tomography has become the most widely used technique for staging renal adenocarcinoma, partly due to the very high overall accuracy of up to 90% that has been achieved. Ultrasonography is an effective, noninvasive and safe procedure that can be used as an initial method in patients suspected for renal adenocarcinoma. MATERIAL AND METHODS: We studied 58 patients (24 females and 34 males, mean age 55.7 years) between 1995-1997 with a histologically confirmed diagnosis of renal adenocarcinoma. A total of 58 patients underwent radical nephrectomy for renal adenocarcinoma. Preoperatively. All patients were examined both by ultrasound and computerized tomography for various tumors characteristics, most commonly evaluation of tumor extension into perirenal structures and major veins invasion. RESULTS AND DISCUSSION: The sensitivity of computerized tomography was higher than that of ultrasonography for the demonstration of tumor extension into the perirenal structures (73.3% vs. 20%). CT does not demonstrate microscopic transcapsular spread of tumor. Criteria for perinephric invasion required a soft-tissue mass at least 1 cm in diameter in the perinephric space. False positive diagnoses do occur. This can be attributed to perinephric oedema, fat necrosis or fibrosis from remote inflammation which may simulate perinephric soft tissue nodules. For surgical planning it is important to determine whether the tumor extends into renal veins and inferior vena cava. Computerized tomography is better to study invasion of inferior vena cava than ultrasonography (100% vs. 66.6%). With regard to renal veins invasion both imaging procedures made false negative results, mainly ultrasonography. In relatively high proportion of cases overlying bowel gas precludes adequate visualization of the renal veins by ultrasonography. CONCLUSION: Newer imaging modalities such as ultrasonography and computerized tomography have superseded conventional radiological methods in the diagnosis and evaluation of renal adenocarcinoma. Our results show that ultrasonography alone is unreliable in detecting tumor spread. Computerized tomography appears to be a more sensitive means of identifying tumor thrombus and tumor extension into perirenal structures. Perinephric tumor spread is the most difficult to detect but is of minor importance if radical nephrectomy is planned

Despite sophisticated equipment like computerized tomography, in some cases doctors have a problem with the diagnostic procedure in relation to patients with serious injuries of the central nervous system (CNS). There may be no clinical signs of disorders of the CNS, or other evidence of difficulties, but diffuse axonal lesions and demyelinisation processes often exist. This type of lesion is a special pathomorphological entity, known as the syndrome of patient who talks and dies. Macroscopical and microscopical findings are poor and rare, especially in the hours immediately following the injury. The main findings are not evidential and the problem is the explanation of sudden death from unknown causes. The following studies are based on human tissue analyses. They are based on the analyses of the CNS of patients who suffered from brain trauma. The specimens from the brain stem were taken in order to perform histological, microscopic analysis. Percentage value of surface of myelin for the control group was X1 38.62% for HE technique and X1 33.46% for Gomory's method. The value for the test group was X2 16.12% for HE technique and X2 13% for Gomory's technique. Statistical probability for both groups was 95% (P < 0.05; T = 14.9). Application of these procedures helps legal authorities to make trials more objective

The vascular network of the area striata consists of four vascular layers. The capillary network of the first vascular layer is completely filled only in some parts of the area striata. The capillary networks of second, third and fourth vascular layer have high density, although the capillary networks in border zones of each two adjacent cortical arteries have lower density. In the area striata the fountain-like arteries have been found, with some collateral branches dividing in fountain-like branches, too. In the brain of a 70 year old male we have found collateral branches initially twisted around its main trunk. The tangential sections of the area striata show the existence of vertically-oriented vascular units with centrally located venous vessel surrounded with one or two arterial rings

Vascular network of gyrus cinguli has been examined in adult brains. This vascular network is extended in the form of a cone from lower to upper lip of Sulcus corporis calosi. The blood vessels in the area of lower lip and bottom of the Sulcus corporis calosi are oriented obliquely, almost parallel to cerebral cortex surface, while in the area of upper lip of sulcus are oriented perpendicularly to the cerebral cortex surface. Arteries in this area have few recurrent branches, while fountain shaped arteries are found infrequently. Shorter spiral arteries are found, too. Longer veins predominates in this area (V4 and V5). Drainage territories of certain veins are larger than irrigation territories of the appropriate arteries

The aim of the study regarding adult brains is to determine the sources of vascularization, vascular area, the size and density of the capillary network of the human subfornical organ. The examined brain blood vessels under filled with a mixture of Indian ink and gelatin. The serial paraffin sections of 50 and 200 microns were cleared after Spalteholz. In the vascularization of this neuroendocrine structure of the diencephalon, two arterial stems take part with their branches: a. cerebri anterior and a. choroidea posterior. In order to quantify the density of the capillary network, the authors used the standard stereologic parameters volume density, surface density and mean radius of blood vessels. By the comparative test of obtained mean values of males and females no statistically significant differences pertaining to sex and in respect to the size and density of capillary network in subfornical organ were confirmed. While the precise functions of the human subfornical organ have yet to be fully elucidated, the similarity in organization of this region to the vascular organ of the lamina terminalis, has led several authors to suggest that the subfornical organ is a site of receptors which are stimulated by circulating angiotensin II to induce water drinking and vasopressin secretion