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  • Author: J. Bezakova x
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Micro RNAs: an arguable appraisal in medicine

Abstract

Micro RNAs (miRNAs) represent a newly discovered class of regulatory molecules in the human body. miRNA is a short double stranded RNA sequence interfering with mRNA, causing in most cases, inhibition of translation. Synthesis of miRNAs shows an increasing developmental pattern and postnatally miRNAs are synthesized in all cells possessing transcriptional machinery. miRNAs usually target several mRNAs and therefore conclusive evidences proving their functions are not always ease to be acquired. In spite of this difficulty, functions of miRNAs were firmly established in the development, the cardiovascular and neural diseases, and cancer. Many miRNAs have been reported to be associated with physiological state of cells and/or tissues. This finding becomes fundamental, especially when consider that these miRNAs can be released from cell into intracellular space or circulation. Correlation between miRNA production in tissues and its contribution to multisource miRNA pool in the circulation is in a focus of biomarker-oriented researchers. Recently, circulating miRNAs have been suggested to be applicable as biomarkers in several types of cancer, cardiovascular injury, and diabetes. Role of miRNAs in the organism intercellular signaling is still under the broad investigation. Several miRNA mimics, intended for treatment of disease, are being currently tested in the clinical trials.

Open access
Progress in micro RNA focused research in endocrinology

Abstract

Micro RNAs (miRNAs) are small regulatory molecules of increasing biologists’ interest. miRNAs, unlikely mRNA, do not encode proteins. It is a class of small double stranded RNA molecules that via their seed sequence interact with mRNA and inhibit its expression. It has been estimated that 30% of human gene expression is regulated by miRNAs. One miRNA usually targets several mRNAs and one mRNA can be regulated by several miRNAs. miRNA biogenesis is realized by key enzymes, Drosha and Dicer. miRNA/mRNA interaction depends on binding to RNA-induced silencing complex. Today, complete commercially available methodical proposals for miRNA investigation are available. There are techniques allowing the identification of new miRNAs and new miRNA targets, validation of predicted targets, measurement of miRNAs and their precursor levels, and validation of physiological role of miRNAs under in vitro and in vivo conditions. miRNAs have been shown to influence gene expression in several endocrine glands, including pancreas, ovary, testes, hypothalamus, and pituitary.

Open access
Study of stability of potential betaadrenolytics, derivatives of the [(arylcarbonyl)oxy]aminopropanol by kinetics of alkaline hydrolysis

Study of stability of potential betaadrenolytics, derivatives of the [(arylcarbonyl)oxy]aminopropanol by kinetics of alkaline hydrolysis

This work deals with the study of the stability of six derivatives of the [(arylcarbonyl)oxy]amino propanol with carbamate substitution on the benzene ring. The studied compounds are different in the substitution on the amine group in the side chain as well as in the substitution on the carbamate functional group. The hydrolysis of compounds was measured in the aqueous-ethanol sodium hydroxide solution (0.1 mol.l-1) at 25, 37, 45 and 60°C spectrophotometrically in the ultraviolet and visual regions. The studied compounds possess two functional groups, which undergo hydrolysis. The pseudo-first order rate constants of hydrolysis for individual reaction steps were determined. The ester functional group of compounds hydrolyses very quickly in this medium. The compounds possessing the tertiary substitution on the amino group are less stable toward alkaline hydrolysis. The course of hydrolysis of compounds was also investigated by thin layer chromatography (TLC).

Open access
Study of physico-chemical properties of potential beta-adrenolytics

Abstract

The aim of this paper is the study of physico-chemical properties of the chosen compounds, derivatives of 2-hydroxy-3-[2-(4-methoxyphenyl) ethylamino]propyl-4-[(alkoxycarbonyl)amino]benzoates and 2-hydroxy-3-[2-(2-methoxyphenyl)ethylamino]propyl-4-[(alkoxycarbonyl) amino]benzoates with potential ultra-short beta-adrenolytic activity. The studied compounds are different in the position of the substituent on the benzene ring in the side chain as well as in the aromatic ring in position 4 with alkyl- (methylto butyl-) carbamate. The physico-chemical characteristics, for example, lipophilicity, surface activity, adsorbability, acidobasic properties etc., are very important for the explanation of the relationship between structure and biological activity of the drug. These parameters serve as the base of quantitative structure-activity study. The goal of this work is to establish the spectral characteristics of studied compounds in UV-area, pKa values, the parameters of lipophilicity (the values of Rf and RM from thin layer chromatography, retention time t´R and capacity factor k´ from liquid chromatography and experimental partition coefficients log P´ values), surface tension, critical micelle concentrations, the adsorbability of compounds expressed by percent of adsorbed compound on active charcoal β% as well as by Freundlich adsorption isotherms. The obtained values are correlated with the parameters characterising the size of molecule, for example, the number of carbon atoms on carbamate functional group.

Open access
Evaluation of Stability of Potential Betaadrenolytics in Various Solutions by thin Layer Chromatography and by Kinetics of Hydrolysis

Abstract

The aim of this work is the study of stability and kinetics of hydrolysis of the chosen compounds, derivatives of 2-hydroxy-3-[2-(4-methoxyphenyl)ethylamino]propyl-4- [(alkoxycarbonyl)amino]benzoates and 2-hydroxy-3-[2-(2-methoxyphenyl)ethylamino] propyl-4-[(alkoxycarbonyl)amino]benzoates with potential ultra-short beta-adrenolytic activity. The studied compounds are different in the position of the substituent on the benzene ring in the side chain as well as in the aromatic ring in position 4 with alkyl- (methyl- to butyl-) carbamate. Thin layer chromatography and UV-area spectrophotometry are used in order to establish the stability of these potential pharmaceuticals. The stability studies of the compounds were examined in acidic and alkaline media, in buffers and due oxidation at room and at elevated temperature chromatographically, and Rf values of incipient products and degradation products were detected. Kinetics of acid and base hydrolysis in various solutions at temperatures 80 °C and 100 °C were examined through UV-area spectrophotometry. Kinetic parameters such as rate constant k, half-life period t1/2 and usable life t90 were determined.

Open access