Current Pharmaceutical Biotechnology - Volume 6, Issue 4, 2005

Human exploration of space raises plenty of questions regarding physiological changes within the body subjected to a new and foreign environment. Nearly every component of the human body is affected. During microgravity conditions, the almost complete reduction in weight of all its components, plus exposure to heightened levels and different types of radiation may work together to increase risk during space t Read More

We used various orthostatic stimulus combinations to better understand the physiology and countermeasure potential of repeated change of body position in humans. The purpose of the investigations reported was threefold: To investigate cardiovascular and hormonal effects of repeated transition between partially antiorthostatic (-30° HDT) and partially head-up passive body tilt (+30° HUT). Protocol Y denotes the repeate Read More

This review summarizes what has been learned from studies of human neurovestibular system in weightless conditions, including balance and locomotion, gaze control, vestibular-autonomic function and spatial orientation, and gives some examples of the potential Earth benefits of this research. Results show that when astronauts and cosmonauts return from space flight both the peripheral and central neural processes Read More

Cardiovascular adaptations driven by exposure to weightlessness cause some astronauts to experience orthostatic intolerance upon return to Earth. Maladaptations of spaceflight that lead to hemodynamic instability are temporary, and therefore astronauts provide for researchers a powerful model to study cardiovascular dysfunction in terrestrial patients. Orthostatic intolerance in astronauts is linked to changes in th Read More

The present manuscript summarizes recent discoveries that were made by studying salt and fluid homeostasis in weightlessness. These data indicate that 1. atrial natriuretic peptide appears not to play an important role in natriuresis in physiology, 2. the distribution of body fluids appears to be tightly coupled with hunger and thirst regulation, 3. intrathoracic pressure may be an important co-regulator of body fluid homeos Read More

The detrimental impact of long duration space flight on physiological systems necessitates the development of exercise countermeasures to protect work capabilities in gravity fields of Earth, Moon and Mars. The respective rates of physiological deconditioning for different organ systems during space flight has been described as a result of data collected during and after missions on the Space Shuttle, International Space Read More

Autonomic neural functions are important to regulate vital functions in the living body. There are different methods to evaluate indirectly and directly autonomic, sympathetic and parasympathetic, neural functions of human body. Among various methods, microneurography is a technique to evaluate directly sympathetic neural functions in humans. Using this technique sympathetic neural traffic leading to skeletal muscles ( Read More

The human cardiovascular system and regulation of fluid volume are heavily influenced by gravity. When decreasing the effects of gravity in humans such as by anti-orthostatic posture changes or immersion into water, venous return is increased by some 25%. This leads to central blood volume expansion, which is accompanied by an increase in renal excretion rates of water and sodium. The mechanisms for the changes Read More

Echocardiographic measurements of astronaut cardiac function have documented an initial increase, followed by a progressive reduction in both left ventricular end-diastolic volume index and stroke volume with entry into microgravity (μ-G). The investigators hypothesize that the observed reduction in cardiac filling may, in part, be due to the absence of a gravitational acceleration dependent, intraventricular hydrostatic pre Read More

Exposure to space flight conditions has been shown to result in alterations in immune responses. Changes in immune responses of humans and experimental animals have been shown to be altered during and after space flight of humans and experimental animals or cell cultures of lymphoid cells. Exposure of subjects to ground-based models of space flight conditions, such as hindlimb unloading of rodents or chronic bed rest Read More