Selected physicochemical properties of amniotic fluid according to week of pregnancy.

BACKGROUND: A hundred years ago, scientists believed that amniotic fluid is a yellowish hypotonic mixture of foetal urine and maternal transudate with peculiar odour. Current knowledge shows that it represents a dynamic, complex mixture of inorganic and organic compounds. OBJECTIVES: Despite modern technological procedures, information is still lacking about the composition and properties of amniotic fluid. We focused on dynamics of selected physical and chemical properties of the amniotic fluid with the increasing gestational week. METHODS: The physicochemical characteristics of 89 amniotic fluid samples were determined according to the week of pregnancy. The determination of pH, specific gravity, glucose and nitrites was performed immediately, at room temperature. RESULTS: Our results show a significant negative correlation between week of pregnancy and semi-quantitative determined parameters of specific gravity (p < 0.001), pH (p < 0.01) and glucose (p < 0.001) values. Within the whole group of samples (n = 89), 29 % (n = 26) were nitrites positive (N+) and 71 % (n = 63) nitrites negative (N-). CONCLUSION: In this study were determined basic parameters of amniotic fluid, which could be related to a wide range of pathological states (Tab. 2, Fig. 1, Ref. 27).

[The Importance of MITF Signaling Pathway in the Regulation of Proliferation and Invasiveness of Malignant Melanoma]. / Význam signálnej dráhy MITF pri regulácii proliferácie a invazivity malígneho melanómu.

BACKGROUND: Malignant melanoma is one of the most aggressive types of cancers. Melanoma is derived from pigment-producing cells, melanocytes, which are characterized by a specific survival mechanism. Microphthalmia-associated transcription factor (MITF-M) plays a role in the metabolism of melanoma and is involved in the regulation of the expression of multiple genes mediating processes such as melanogenesis, proliferation, differentiation, and melanocyte survival. The expression of this transcription factor in melanocytes is activated by several signaling pathways, and reduced expression or function of MITF-M can cause the dysregulation of anti-apoptotic mechanisms. MITF-M is also involved in matrix metalloproteinase 14 (MMP14) activity, which is responsible for shape changes in melanocytes and increases in their motility and invasiveness. Very low levels of expression of MITF-M are found in human melanocytes with an invasive phenotype, indicating that this transcription factor acts as a suppressor of the metastatic process. Cancer cells with low expression of cytosolic/nuclear ß-catenin have a small amount of MITF-M 14 that is insufficient to inhibit MMP transcription. The enzyme catalyzes the degradation of laminin and fibronectin, thereby changing the shape of melanocytes, which leads to their increased mobility and invasiveness. AIMS: This review describes the regulatory pathway of MITF-M activation, its involvement in the proliferation of transformed melanocytes, and its role in increasing the invasiveness of malignant melanoma. A detailed understanding of the MITF-M signaling pathway is highly topical and could help to develop new diagnostic and therapeutic applications for patients with malignant melanoma.Key words: neoplastic cell transformation - melanoma - MITF transcription factorThis work was supported by grant projects VEGA 1/0115/14 and VEGA 1/0873/16.The authors declare they have no potential confl icts of interest concerning drugs, products, or services used in the study.The Editorial Board declares that the manuscript met the ICMJE recommendation for biomedical papers.Submitted: 4. 12. 2015Accepted: 14. 6. 2016.