Unexpected cleavage of upper rim-bridged calix[4]arenes leading to linear oligophenolic derivatives.

Regioselective meta-mercuration followed by Pd-catalysed intramolecular bridging gave birth to a novel type of calixarene bearing a single bond bridge between the meta positions of the neighboring aromatic subunits. These bridged derivatives possess extremely distorted cavities that imply possible amended properties over common calix[4]arenes. This new type of calixarene reactivity can be documented by acid-/electrophile-mediated cleavage of the basic macrocyclic skeleton leading to open oligomeric structures-the behavior of which has never been observed before in classic calix[4]arenes bearing alkoxy groups on the lower rim.

Malignant tumors of the uterine corpus: molecular background of their origin.

Tumors of the uterine corpus can be divided into two main groups: endometrial tumors and mesenchymal tumors. The former ones are common gynecological diseases, whereas malignant mesenchymal tumors, which behave in a much more aggressive way, are quite rare with a poorer prognosis. The most common type of endometrial tumors is endometrioid adenocarcinomas, and in case of mesenchymal tumors, these are carcinosarcomas, or leiomyosarcomas, if only clear types of tumors are taken into account. The objective of this article is to review molecular-genetic abnormalities associated with tumorigenesis of both types of tumors, with focus on the most aggressive forms. This view includes a different expression pattern of genes, usually aberrant in cases of uterine cancer that can arise due to epigenetic modifications, mostly hypermethylation of promoters or microRNA (miRNA)'s interference with concrete genes. Furthermore, clinical predispositions of tumorigenesis, involving hormonal factors, age, and ethnicity, are also mentioned.

Histological status of the liver in relation to serum aminotransferase levels in patients with chronic hepatitis C.

INTRODUCTION: The diagnosis of chronic hepatitis C is based on serological, biochemical and histological parameters. However, the correlation between the activity of liver enzymes and the degree of histomorphological damage may be very poor. It has been recognised that serum aminotransferase levels do not accurately reflect the extent of liver inflammation. OBJECTIVES: The aim of this retrospective study was to determine the predictive value of ALT, AST levels and AST/ALT ratio compared to histological grading and staging in patients with chronic hepatitis C. MATERIAL AND METHODS: We analysed data of 58 chronically HCV-infected adult patients who had udergone core needle liver biopsy. RESULTS AND CONCLUSION: In our study, most patients with chronic hepatitis C manifested with only mild histological findings. Although liver enzymes levels in general corresponded with the activity of the disease, even a normal level could not exclude a serious histological liver damage. Therefore, these facts should remind the physicians to perform a liver biopsy prior to therapy (Tab. 3, Ref. 19). Full Text (Free, PDF) www.bmj.sk.

A mechanoreceptor model for rapidly and slowly adapting afferents subjected to periodic vibratory stimuli.

A simple model of Freeman and Johnson on cutaneous mechanoreceptors is modified by introducing mechanisms for hyperexcitation and refractoriness. These lead to significant improvements in the match between the neural and model data.

[Deep soft-tissue leiomyoma]. / Leiomyóm hlbokých mäkkých tkanív.

Deep soft tissue leiomyomas (DSTL) are very rare. For this reason they are neither histologically, nor clinically reliably characterized, especially regarding their dignity. The authors present two cases of leiomyomas which grew from the deep soft tissue in the region of the head and perineum. Both cases involved women 43 and 63 years of age. Characteristically morphological traits, as e.g. good borderline of lesion, the presence of fibrous pseudocapsule, and classical morphologic appearance of leiomyoma were present in both cases. While in the first case the foci of dystrophic calcification within regressively altered foci of the tumour were found, the second case involved the presence of foci of myxohyalin degeneration of stroma. The first tumour contained also parts with a palisade arrangement of nuclei which gives a hint of resemblance to that of neurilemmoma. Mitoses did not exceed the HPF index of 2/10 in neither of the cases. Both cases were S-100 immunohistochemically negative, actin and human muscle actin were significantly positive, desmin was weakly or mediately positive, and vimentin significantly or mediately positive. The first case involved a clinical recurrence of a histologically verified leiomyoma after 5 years in the same location with MI being of zero value. Regarding the presented characteristics, the authors classify the described leiomyomas as DSTL. These tumours with an uncertain prognosis can metastatize despite their benign morphology. (Tab. 2, Fig. 4, Ref. 19.)