Daytime Exposure to Blue Light Alters Cardiovascular Circadian Rhythms, Electrolyte Excretion and Melatonin Production.

Artificial light is characterized by certain features of its impact on the body in terms of its spectral distribution of power, duration of exposure and intensity. Short waves, perceived as blue light, are the strongest synchronizing agent for the circadian system. In the present work, we investigated the features of the circadian rhythms of blood pressure (BP), heart rate (HR), the excretion of electrolytes and the secretion of melatonin in normotensive (Wistar-Kyoto) and hypertensive (SHR) rats under the action of monochromatic blue light in the daytime period. It was found that the exposure of Wistar-Kyoto rats to monochromatic blue light was accompanied by a significant decrease in nighttime and 24 h systolic BP. The most remarkable changes are characteristic of the HR in SHR rats under monochromatic light. A significant decrease in HR in each time period was found, but the predominance of nighttime over daytime values remained in SHR animals. There was also a significant increase in the mesor of the HR in SHR rats. Additionally, the amplitude of diastolic BP and HR, as well as the range of oscillations in HR, were significantly increased compared with the standard light pattern. In contrast to SHR rats, the regulation of the circadian rhythms in Wistar-Kyoto rats was more flexible and presented more changes, which may be aimed at the adaptation of the body to environmental conditions. For Wistar-Kyoto rats, an increase in the level of excreted electrolytes was observed under the action of monochromatic light, but no similar changes were found in SHR rats. For Wistar-Kyoto rats, a significant decrease in the urine concentration of aMT6s in the daytime and nighttime periods is characteristic, which results in the loss of the circadian rhythm. In SHR rats, there was a significant decrease in the nighttime content of aMT6s in the urine, while the daytime concentration, on the contrary, increased. The obtained data demonstrate that prolonged exposure to monochromatic blue light in the daytime period affects the circadian structure of the rhythms of the cardiovascular system, the rhythm of electrolyte excretion and the production of epiphyseal melatonin in wild-type and hypertensive animals. In SHR rats, the rhythms of BP and HR exhibit a more rigid pattern.

Assessing the biological effects of microwave irradiation on human semen in vitro and determining the role of seminal plasma polyamines in this process.

The aim of the present study was to investigate the influence of millimeter-wave electromagnetic (MW) irradiation on normal and pathological human sperm in vitro, and to evaluate a possible role of polyamines (PA) in this process. The stability of sperm membranes, the number of apoptotic gametes, and the content of seminal plasma PA in the ejaculates of fertile and subfertile men were compared before and after short-term MW electromagnetic exposure in vitro. The ejaculate samples were collected from healthy donors [n=25, age 22-38 years old (y.o.), average age 30.6±1.1 y.o. (mean ± SEM)] and from subfertile men (n=78, age 25-48 y.o., average age 34.1±0.8 y.o.) and exposed to MW radiation. The electromagnetic field had a wavelength of 7.1 mm, a frequency of 42.194 GHz and an exposure time of 20 min. The fragility of sperm membranes was evaluated by their resistance to sodium chloride solution (Milovanov test) and to acetic acid (Joel test). Acrosin activity was assayed spectrophotometrically. Apoptosis was determined by the externalization of phosphatidylserine on the outer side of the sperm membrane and propidium iodide staining. The PA levels were determined by agar gel electrophoretic fractionation. An increase in the resistance of sperm membranes, a decrease in acrosin activity, a decrease in the number of apoptotic gametes and a decrease in the seminal plasma PA concentrations were found after exposure of the native human sperm to low-intensity MW irradiation. Two types of reactions were revealed for the subfertile samples. The results revealed positive bio-effects of specific microwaves on the human semen and the participation of PA in the realization of these effects.

BCL2­regulated apoptotic process in myocardial ischemia­reperfusion injury (Review).

The leading cause of death in developed countries is cardiovascular disease, where coronary heart disease is the main cause of death. Myocardial reperfusion is the most significant method to prevent cell death after ischemia. However, restoration of blood flow may paradoxically lead to myocardial ischemia­reperfusion injury (MI/RI) accompanied by metabolic disturbances and cardiomyocyte death. As the myocardium has an extremely limited ability to regenerate, the mechanisms of regulated cell death, including apoptosis, are the most significant for contemporary research due to their reversibility. BCL2 is a key anti­apoptotic protein. There are several signaling pathways and compounds regulating BCL2, including PI3K/AKT and MEK1/ERK1/2, JAK2/STAT3, endothelial nitric oxide synthase, PTEN, cardiac ankyrin repeat protein and microRNA, which can serve as targets for modern methods of cardioprotective therapy inhibiting intrinsic apoptosis and saving viable cardiomyocytes after MI/RI. The present review considers the mechanisms of Bcl2­regulated apoptosis in the development and treatment of MI/RI.

Polyamine Analogues of Propanediamine Series Inhibit Prostate Tumor Cell Growth and Activate the Polyamine Catabolic Pathway.

BACKGROUND/AIM: Polyamines are important for the growth of eukaryotic cells. At high levels, they promote proliferation, invasion and migration of tumour cells. Polyamine metabolism is an important new target for anticancer therapy. Some polyamine analogues can have an inhibitory effect on tumour cells. The aim of this study was to explore the potential of certain butylated derivatives of propanediamine for prostate cancer chemotherapy. MATERIALS AND METHODS: Human prostate cancer cells, LNCaP, were used for the evaluation of the antiproliferative activity of polyamine analogs and their influence on spermine oxidase. RESULTS: Tetrabutyl propanediamine and two new polyamine analogues inhibited the growth of LNCaP cells. At the same time, a strong activation of spermine oxidase was observed. CONCLUSION: The investigated compounds demonstrated their potential value in the therapy of human prostate cancer. Their effect might be attributed to the activation of the polyamine catabolic pathway.

The investigation of structure-activity relationship of polyamine-targeted synthetic compounds from different chemical groups.

The polyamine (PA) metabolism is involved in cell proliferation and differentiation. Increased cellular PA levels are observed in different types of cancers. Products of PA oxidation induce apoptosis in cancer cells. These observations open a perspective to exploit the enzymes of PA catabolism as a target for anticancer drug design. The substances capable to enhance PA oxidation may become potential anticancer agents. The goal of our study was to explore how the mode of ligand binding with a PA catabolic enzyme is associated with its stimulatory or inhibitory effect upon PA oxidation. Murine N1-acetylpolyamine oxidase (5LFO) crystalline structure was used for molecular docking with ligands of various chemical structures. In vitro experiments were carried out to evaluate the action of the tested compounds upon PA oxidative deamination in a cell-free test system from rat liver. Two amino acid residues (Aps211 and Tyr204) in the structure of 5LFO were found to be significant for binding with the tested compounds. 19 out of 51 screened compounds were activators and 17 were inhibitors of oxidative deamination of PA. Taken together, these results enabled to construct a recognition model with characteristic descriptors depicting activators and inhibitors. The general tendency indicated that a strong interaction with Asp211 or Tyr204 was rather typical for activators. The understanding of how the structure determines the binding mode of compounds with PA catabolic enzyme may help in explanation of their structure-activity relationship and thus promote structure-based drug design.