Le Grand écho du Nord de la France

13 octobre 18991899/10/13 (A81,N286).Appartient à l’ensemble documentaire : NordPdeC

Effect of steroid hormone deprivation on the expression of ecto-ATPase in distinct brain regions of female rats

Abundant evidence indicates that ATP and adenosine act as neurotransmitters or co-transmitters, influencing nerve cell physiology in various ways. Therefore, regulation of ATP-metabolizing enzymes is essential for the normal development and function of neuronal tissue. In the present study we have examined the effect of gonadal (OVX) or adrenal (ADX) steroid hormone deprivation on the activity and expression of synaptic membrane ecto-ATPase in three extrahypothalamic brain areas of female rats, primarily not associated with reproductive function. It was shown that OVX significantly increased ecto-ATPase activity and the relative abundance of this enzyme in the hippocampal (Hip) and caudate nucleus (CN), but not in brain stem (BS) membrane preparations. ADX was followed by an upregulation of the enzyme activity and its relative abundance in all the brain areas investigated. The highest enzyme activity and the most profound effects of OVX and ADX were detected in the CN. The results obtained indicate that ADX and OVX upregulate the expression of ecto-ATPase, potentiating the production of adenosine in synaptic cleft thus modulating the activity of numerous neurotransmitter systems in distinct areas of the CNS

Neuroendocrine and oxidoreductive mechanisms of stress induced cardiovascular diseases

Running title: Molecular mechanism of stress induced cardiovascular disease 1 Summary The presented review addresses a number of basic molecular pathways that play crucial role in perception, transmission and modulation of the stress signals, and conduct adaptation of the vital processes in the cardiovascular system (CVS). These, highly complex systems for intracellular transfer of information include stress hormones and their receptors, stress-activated phosphoprotein kinases, stress-activated heat shock proteins, and antioxidant enzymes maintaining oxidoreductive homeostasis of the CVS. Failure to compensate for the deleterious effects of stress may result in development of different pathophysiologies in the CVS, such as, ischemia, hypertension, atherosclerosis and infarction. Stress-induced disbalance in each of the CVS molecular signaling systems and their contribution to the CVS malfunctioning is reviewed. The general picture of the molecular mechanisms of the stress-induced pathophysiology in the CVS pointed out the importance of stress duration and intensity as etiological factors, and suggested that future studies should be complemented by the careful insights into the individual factors of susceptibility to stress, prophylactic effects of 'healthy' life styles and beneficial action of antioxidant rich nutrition

The late effects of proton irradiation on cell growth, cell cycle arrest and apoptosis in a human melanoma cell line

The aim of this work is the in vitro study of the late effects of single proton irradiation on HTB63 human melanoma cell growth, cell cycle and cell death. The experimental conditions were focused on analyzing the effects of irradiation on the periphery of tumour that can be, in clinical practice, close to critical organs. Confluent cell monolayers were irradiated with single doses ranging from 1 - 20 Gy, using proton beams having an energy of 22.6 MeV at the target. Antiproliferative effect of protons, cell cycle analysis and initiation of cell death, were followed 48 hours after irradiation. The inhibition of melanoma cell growth was observed, especially after single application of 12 and 16 Gy. Cell cycle analysis and cell viability have shown the G2/M and G1/G0 arrest of irradiated cells correlating with the increase of the applied dose. The flow cytometric analysis has shown presence of apoptotic nuclei. These data demonstrate that irradiation with protons, under the chosen experimental conditions, have significant effects on melanoma cell growth inhibition being dose dependent, G2/M cell cycle arrest and appearance of apoptotic nuclei, even 48 hours after irradiation. The results obtained may help the understanding of the relationship between cell proliferation, death and cell cycle regulation of melanomas after proton irradiation

Inhibition of human melanoma cell growth by proton irradiation

The aim of this work is the in vitro study of human melanoma cell growth modulation after irradiation with protons. Confluent cell monolayers were irradiated with single doses ranging from 1 to 20 Gy, using proton beams having energy of 22.6 MeV at the target. 48 hours after irradiation, cell growth, cell cycle analyses and initiation of cell death were followed. The obtained results were compared with the effects of glucocorticoid hormones. The inhibition of melanoma cell growth was observed, especially after single application of 12 and 16 Gy. Cell cycle analyses of melanomas after proton irradiation, have shown the G2/M arrest of irradiated cells corresponding with the increase of applied dose. The flow cytometric analysis has shown presence of apoptotic nuclei. Glucocorticoid treatment has shown modest melanoma cell growth inhibition, cell cycle arrest in G2/M phase and ladder pattern on agarose gel electrophoresis.International Conference on Ocular Pathologies Therapy with Proton Beams, Oct 12-13, 2000, Catania, Ital