Influence of Hyperbaric Oxygen on Blood Vessel Reactivity: Concept of Changes in Conducted Vasomotor Response

The actions of oxygen in the body are extremely complex, and are also involved in various signalling pathways. Hyperbaric oxygen is known to contribute to the improvement of conditions where tissue circulation is suboptimal, and has considerable usage in different treatment protocols and experimental investigations. However, the precise mechanism by which hyperbaric oxygen changes the functioning of coordinated blood vessel systems and microcirculation is still unknown. Taking into account the known facts, we suggest that hyperbaric oxygen induces changes in conducted vasomotor responses, and in that way influences vascular sensitivity and reactivity to vasodilators and vasoconstrictors. Conducted vasomotor responses are constrictions and dilations that are propagated along the vessel, leading to changes in vessel diameter on a certain distance of the initial site of vasoactive substance activity. Because these vascular responses are of substantial significance in physiological processes, their modification would subsequently cause alterations of blood vessel function and tissue perfusion that could explain observed effects of hyperbaric oxygen. We also discuss potential molecular targets of hyperbaric oxygen, investigation of which could presumably help in the eventual clarification of hyperbaric oxygen action

Different Roles of Sex Steroid Hormones in the Pathogenesis of Vascular Dysfunction and the Development of Cardiovascular Disease in Men and Women

In this review an overview of current literature on the topic of the relation between sex steroid hormones and cardiovascular diseases (CVDs) is presented. The influence of the mentioned hormones on the three levels has been analyzed: their interaction with the blood vessel receptors, their modulation of the vascular function, and finally their role in the pathogenesis of CVDs. This review is focused not only on already known facts of the protective role of estrogens and the inceptive role of testosterone, but attempts to give examples of their opposite effects on vascular function and development of CVDs

Microcirculation impairment and blood pressure in sepsis

Blood pressure is crucial for the tissue perfusion, oxygenation andelimination of metabolites in normal tissue. In septic patients itmay be altered by several mechanisms. Endothelial lesions andimpaired vasoregulation resulting from bacteriemia may producevasodilatation, hypotension, tissue hypoxia and decrease in theblood velocity. These events may favour disseminated intravascularcoagulation in septic patients, and thus pronounce perfusionmisdistribution. Since hypotension is commonly treated byvasoactive drugs to increase vascular tone toward normal values,more pronounced peripheral tissue ischemia may result. Duringthe process of blood pressure regulation in septic patients a diversityof physiological parameters should be encountered, i.e. age,body weight, core temperature, overall patients’ cardiovascularperformance, anemia, and protein status. In a healthy, adult person,in the absence of other causes of hypotension systolic bloodpressure of > 90 mmHg or mean arterial pressure ≥ 70 mmHgshould maintain adequate tissue perfusion. Together with specificantibiotics, therapeutic procedures like haemodilution, use of vasoconstrictors,vasopressin and its analogue terlipressin, corticosteroidsare currently used to improve outcome of hypotensive septicpatients. Numerous studies were undertaken to point the valuesof the biochemical tests suggesting a need for prompt intervention.The arterial lactate, cortisol response, TNF, interleukin (IL)6, IL-12p70 and IL-12p40 production, together with submucosal(gastric intramucosal or sublingual) CO2 values were proven as indicative.These may suggest whether microcirculatory impairmentis reversible or not, and which therapeutic maneuver should beappropriate

The Web system for coronary disease risk estimation by logistic regression (“CHD risk”)

Aim Coronary and heart diseases (CHD) represent one of thegreatest medical problems in the developed world. To facilitatethe CHD probability estimation procedure, as well as to speed upthe procedure of making and issuing patient’s final diagnosis, wedeveloped the Risk estimation application (‘’CHD Risk’’).Methods Risk estimation is based upon a multivariate analysis ofstatistical data by using logistic regression as a method for probabilityestimation. The method estimates how the final outcome isinfluenced by every single factor. Risk factors represent independentvariables of the model, while a coronary disease risk indicatoris dependent variable.Results The ‘’CHD Risk” was tested for three cases and showedapplication credibility. The system provides coronary disease riskprobability estimation for the given risk factor values, as well asadvice for factors whose values exceed the range of normal values.The system allows input of additional statistical data, whichimproves its learning properties.Conclusions Although the “CHD Risk” system can neither makefinal decisions nor replace the medical professionals themselves, itfulfills the aim to develop the web based tool to help the physiciansto monitor their patients’ health condition, as well as to suggestpreventive measures and therapy

Sodium channels and nociception – the effects of local anesthetics

Background and Purpose: Pain is an unpleasant warning sensation of imminent damage of the tissue or organ, and is a very frequent reason for patients to seek the physician\u27s help. The aim of this paper is to give an overview on the role of voltage gated sodium channels in nociception and to highlight the mechanisms of the action of local anesthetics in inhibiting conduction of ion currents, thus affecting the sense of pain. Materials and Methods: A comprehensive search of the literature with key words: voltage gated sodium channels (VGSC), nociception, local anesthetics, α, β- subunit isoforms in Medline was conducted. Results: VGSC isoforms Nav1.7, Nav1.8, Nav1.9 are highly expressed in nociceptive neurons and associated with neuropathic pain syndrome. Human studies demonstrated that point mutations of these isoforms, particularly Nav1.7 underlie insensitivity or hypersensitivity to pain. The sodium channel blockers are anesthetics of choice for local analgesia and anesthesia. However, currently available drugs are not considered selective enough and have relatively narrow therapeutic windows, which can limit their usefulness. Isoform – selective pharmacological blockers or gene therapy approaches targeted at down-regulating specific isoforms could show increased therapeutic efficacy for treating pain. Conclusions: Due to restrictive appearance of isoforms Nav1.7 and Nav1.8 in nociceptive neurons, drugs targeting these isoforms would be of great interest, especially in treatment of neuropathic pain syndrome

Scaling-up Undergraduate Medical Education: Enabling Virtual Mobility by Online Elective Courses

AIM: To evaluate online elective courses at Croatian medical schools with respect to the virtual mobility of national teachers and students and virtual team collaboration. ----- METHODS: A student-centered virtual learning environment developed within the framework of the European Union Tempus Programme allowed national educational services to design and deliver online undergraduate elective courses. Three online elective courses were created for second-year medical students of four Croatian medical schools by using Moodle, an open-source learning management system. The courses supported problem-, project-, and decision-based learning and required students to work in small collaborative teams using problem-solving and decision-making activities. The purpose was to foster teamwork and produce better outcomes than those potentially achieved through individual work. We evaluated the results of these online courses on the basis of the course test results and students' evaluation questionnaires. ----- RESULTS: Of 68 students enrolled in all e-courses, 97% (n=66) successfully passed the final exam. An anonymous online questionnaire was filled out by 83% (n=50) of the students. The majority expressed their satisfaction with the online electives, mostly because they had more contact with tutors and peers (n=47), better possibilities of self-assessment (n=38), more flexible learning (n=33), better access to learning materials (n=32), faster and easier information retrieval (n=31), and better quality of communication with tutors and peers (n=28). Although 38 of 50 students claimed that participating in e-courses was more demanding than participating in traditional electives, more than half (n=27) would enroll in an e-course again. ----- CONCLUSION: Elective e-courses may be a successful model of how faculty and students at higher education institutions can collaborate and integrate e-learning into their current curricula

Scaling-up Undergraduate Medical Education: Enabling Virtual Mobility by Online Elective Courses Medical Education Medical Education 344

Aim To evaluate online elective courses at Croatian medical schools with respect to the virtual mobility of national teachers and students and virtual team collaboration. Methods A student-centered virtual learning environment developed within the framework of the European Union Tempus Programme allowed national educational services to design and deliver online undergraduate elective courses. Three online elective courses were created for second-year medical students of four Croatian medical schools by using Moodle, an open-source learning management system. The courses supported problem-, project-, and decision-based learning and required students to work in small collaborative teams using problem-solving and decision-making activities. The purpose was to foster teamwork and produce better outcomes than those potentially achieved through individual work. We evaluated the results of these online courses on the basis of the course test results and students' evaluation questionnaires. Results Of 68 students enrolled in all e-courses, 97% (n = 66) successfully passed the final exam. An anonymous online questionnaire was filled out by 83% (n = 50) of the students. The majority expressed their satisfaction with the online electives, mostly because they had more contact with tutors and peers (n = 47), better possibilities of self-assessment (n = 38), more flexible learning (n = 33), better access to learning materials (n = 32), faster and easier information retrieval (n = 31), and better quality of communication with tutors and peers (n = 28). Although 38 of 50 students claimed that participating in e-courses was more demanding than participating in traditional electives, more than half (n = 27) would enroll in an e-course again. Conclusion Elective e-courses may be a successful model of how faculty and students at higher education institutions can collaborate and integrate e-learning into their current curricula

The Role of Nitric Oxide in the Micro- and Macrovascular Response to a 7-Day High-Salt Diet in Healthy Individuals

This study aimed to investigate the specific role of nitric oxide (NO) in micro- and macrovascular response to a 7-day high-salt (HS) diet, specifically by measuring skin microvascular local thermal hyperemia and the flow-mediated dilation of the brachial artery, as well as serum NO and three NO synthase enzyme (NOS) isoform concentrations in healthy individuals. It also aimed to examine the concept of non-osmotic sodium storage in the skin following the HS diet by measuring body fluid status and systemic hemodynamic responses, as well as serum vascular endothelial growth factor C (VEGF-C) concentration. Forty-six young, healthy individuals completed a 7-day low-salt diet, followed by a 7-day HS diet protocol. The 7-day HS diet resulted in impaired NO-mediated endothelial vasodilation in peripheral microcirculation and conduit arteries, in increased eNOS, decreased nNOS, and unchanged iNOS concentration and NO serum level. The HS diet did not change the volume of interstitial fluid, the systemic vascular resistance or the VEGF-C serum level. These results indicate that the 7-day HS-diet induces systemic impairment of NO-mediated endothelial vasodilation, while dissociation in the eNOS and nNOS response indicates complex adaptation of main NO-generating enzyme isoforms to HS intake in healthy individuals. Our results failed to support the concept of non-osmotic sodium storage