Romanian journal of physiology : physiological sciences最新文献

The dynamic study of oxyhemoglobin in general, and especially in traumatic shock, represents one of the aspects of pathophysiology which is of interest to practitioners as well as to pathophysiologists due to its relatively practical accessibility. The study was performed on two groups of 30 subjects: a healthy subjects group and a control group. The patients hospitalized in the Intensive Care Section of the Clinical Hospital Department of Constanţa represented the subjects of the control group. Using an Oximeter--AVL 912 oxylite, the arterial hemoglobin oxygen saturation, venous hemoglobin oxygen saturation and the calculation of arterio-venous oxygen difference were measured in their dynamics. The results showed a diminution of oxygen extraction at the tissular level. We also noticed a good correlation between oxyhemoglobin dynamics and the evolution of the patients during specific therapy.

Our study concentrated upon the modifications of some parameters which characterize uterine smooth muscle contractile activity under the action of active substances. We studied the isotonic contractions of the uterine smooth muscle in a classical organ bath in which we introduced some contracting and relaxing substances. At the beginning, we introduced Oxytocin to determine uterine smooth muscle contractions. After that, we added relaxing substances (Papaverin, Diazepam, Terbutalin, Isoxuprin, Hexoprenalin) in the organ bath, and then, in another protocol, we added combinations of two relaxing substances. We determined for each wave some parameters: minimum, mean, maximum and net amplitude, wave area and duration, the interval between waves, the time while the curve increases from the minimal value of the amplitude to the maximum value, the frequency of contractile waves. For each parameter we determined the variance coefficient (C.V. %), which reflects the regularity of the uterine activity. We observed a regularizing effect of the uterine activity after administration of some active substances. The smallest variance coefficient (C.V. %) was found for HEXO + PAP combination (mean value for C.V. % is 4.71%).

The World Health Organization and the International Society of Hypertension continue to focus on assessing the cardiovascular risk of arterial hypertension and on developing a hierarchy of risk factors. Among the factors involved in the etiopathogeny of arterial hypertension, less attention has been given to the relations between the figurate elements of the blood (red cells and platelets) and the endothelial factors involved in vasomotricity. This motivates further research into the permeability of the erythrocyte and the platelet membrane in physiological and pathological conditions. Modern investigation methods have been employed in the study of a group of 100 patients with hypertension, both females and males, in various stages of the disease, who were compared with a group of controls. Results pointed to alterations of both eryhtrocyte and platelet membrane permeability dependent on the stage of the hypertensive disease and its complications. Despite the important individual variations that limit the diagnostic value of the investigations, they will contribute to an early diagnosis in the initial stages (I and II) of the disease and will point to the possibility of complications to occur. The correlations between alterations of platelet and erythrocyte permeability and the activity of gammaglutamyltransferase, the level of thiolic grouping and of cholesterol in the blood cell membrane provide additional information about the mechanism of interrelations between the latter and the vascular endothelial factors in physiological and pathological conditions such as arterial hypertension in various stages of evolution and its complications.

Any living structure, from cell to the entire organism, can adapt to internal or external factors only by triggering pre-existing mechanisms. All these mechanisms have a morphological support programmed within foetal inactive genes or adult genes with low activity. These genes are activated by a chain of reactions that usually starts with perceiving the stimulus at the membrane level and finishes with the synthesis of some proteins (enzymes, membrane receptors, etc.). The adaptative changes of the enzymatic and structural register would be impossible without the activation of genes other than those operating in normal condition. It is obvious that the same pre-existing genetic mechanism also functions in myocardial hypertrophy or neoangiogenesis. Actually, "a genetic orchestra" is ready to perform at a given moment the new tone suggested by the ever changing condition under which the myocardial fiber acts. However, the concept of programmed adaption has not only a theoretical value; in medical practice, the prediction, prevention and treatment of ischemic heart disease will benefit from the theoretic support of understanding the cardiac adaptative behaviour. It is obvious that this adaptation programmes cannot always save the heart from necrosis and the subject from death due to fatal arrhythmias or cardiogenic shock.

Arterial hypertension, including the elucidation of hypertension pathogenic mechanisms involving elements in the composition of the blood, continues to represent a topical research area. Recent work, such as nuclear magnetic resonance studies looking into red cell permeability, illustrates the presence of modifications of red cell permeability to water (RCPW) related to the stage of arterial hypertension. The identification of a significant increase of RCPW compared to that present in the population with normal arterial pressure values can be useful both in early diagnosis and in warning about a possible predisposition for this condition. At the same time, the dynamic investigation of protonic relaxation time of both intra- and extra-erythrocytic water, the assessment of proton exchange time across the red cell and the calculation of permeability to water enable one not only to diagnose arterial hypertension but also to ascertain the evolution of the disease, its complications and the effectiveness of anti-hypertensive medication. Our studies have also proven the existence of a correlation between the values of systolic arterial pressure and red cell permeability to water. The curve describing the interdependence of the two values has the shape of a bell, in the case of males. The peak of the curve is reached for a systolic pressure of 160 mmHg and gets below the values of the control group in the case of systolic pressures above 200 mmHg. The RCPW test can also be considered a valuable indicator in evaluating the risk of stroke in hypertensive patients. In the chronic therapy of arterial hypertension with various types of anti-hypertensive drugs, one can note differences in the RCPW values related to the effectiveness of the respective medication, to the clinical form and stage of the disease, the sex of the patient as well as to the existence of cerebro-vascular complications.

The personality of the scientist I. Athanasiu united the happy complementarity of an exceptional professor and researcher. If Professor I. Athanasiu perceived science by its past and transmitted it in a synthetized form to his contemporaries, the researcher I. Athanasiu was permanently interested in the future, in the following stages of scientific research. In his short life, Professor I. Athanasiu illustrated brilliantly both aspects of a scientist's personality. Adding these qualities to his vivid, nonalterated and discrete patriotism, shown honestly among foreigners in the major European countries as well as among Romanians and foreigners in his country, his worries for the future of his homeland, especially for its youth, we realise another aspect of I. Athanasiu's personality, that of a scientist and patriot. By his scientific research, I. Athanasiu surpassed the limits of medical-veterinary area, approaching with talent and efficiency its related fields: human medicine and animal biology.

The background concerns the present-day psychobiological construct on stress and its models. Psychoneuroendocrine mechanisms, cellular and molecular alterations, oxidative and immune reactions and stress system disorder, related to physical, psychosocial and emotional stress became hot research areas. Other important directions regard occupational stress, objective and subjective assessment methods and stress prevention and management. For the physiology of exercise the investigation of central and peripheral limiting factors of human physical performances and the involvement of neuroscience to exercise studies are of main interest. A commentary of the stress concept in terms of testability (Popper) and of a paradigm (Kuhn) follows. The contributions of the Cluj laboratory to the neuroendocrine control in stress, exercise and work, leading to some practical outcomes, and the connections between psychoanalysis and the stress construct are discussed.

Stress system is very important in the co-ordination of the generalised stress response, which takes place when a stressor of any kind exceeds a threshold. In our experiments we have analysed aspects of opiate involvement in the interactions among the emotional, motivational and cognitive processes, as well as aspects concerning the relations between physiological and behavioural mechanisms, both in normal conditions and under stress. We also analysed aspects of the interaction between stress system and endogenous opioid systems (e.o.s.). As emotional states interfere with perception and cognition, in our experiments we used suitable variants of the open-field test, which evaluates the exploratory drive and emotional reactivity. We used 30 Wistar male rats, 18 months old, weighing 350-400 g, divided into three groups, of 10 animals each. In order to assess the behaviour of the animals, we have analysed exploratory (cognitive) and non-exploratory (emotional) parameters. In order to evaluate the manner in which endogenous opioid systems are involved in these aspects, different groups of rats were treated with an opiate agonist (codeine syrup, 0.117, 5 ml/kg to approximately 0.5 mg/kg morphine as active compound, p.o.) and an antagonist (naloxone 0.4 mg/kg i.p.), before testing in open-field. To distinguish between the effect of habituation and the effect of the opiate agonist and antagonist, the placebo treatment and the test/retest method were used. At these doses, the opiate agonist has stimulated the exploratory behaviour, while the antagonist has inhibited the cognitive behaviour and enhanced the emotional response. Our experimental data together with data from literature allowed us to present an interactive model that points out a general manner of interaction between emotions and cognition, in relation to the interactions between physiological and behavioural mechanisms.

There has been reported, in some diurnal or equivocal species (man, respectively guinea pig), a circadian rhythm of the phagocytic activity of blood neutrophils, with an acrophase occurring at the end of the light span. The present study, carried out on NMRI adult male mice kept on a LD 12:12 regimen, aimed to assess any circadian variation in the blood neutrophils' phagocytosis level. Basal phagocytic activity was tested against E. coli, every three hours of a 24 h cycle. The results show that phagocytosis in mice's blood neutrophils also presents a rhythmic circadian variation, whose acrophase is delayed with about eight hours compared to that in man, occurring in the second half of the dark period (3:00 h). The occurrence of high circadian phagocytic levels appears to be correlated with the activity type of the species and, of this point of view, mice cannot be used as a model for chronotherapeutical approaches in humans, without keeping in mind the differences between the time structure of the two species.