Increased core body temperature in astronauts during long-duration space missions.

Humans' core body temperature (CBT) is strictly controlled within a narrow range. Various studies dealt with the impact of physical activity, clothing, and environmental factors on CBT regulation under terrestrial conditions. However, the effects of weightlessness on human thermoregulation are not well understood.

Agreement between 24-hour salt ingestion and sodium excretion in a controlled environment.

Accurately collected 24-hour urine collections are presumed to be valid for estimating salt intake in individuals. We performed 2 independent ultralong-term salt balance studies lasting 105 (4 men) and 205 (6 men) days in 10 men simulating a flight to Mars. We controlled dietary intake of all constituents for months at salt intakes of 12, 9, and 6 g/d and collected all urine.

Long-term space flight simulation reveals infradian rhythmicity in human Na(+) balance.

The steady-state concept of Na(+) homeostasis, based on short-term investigations of responses to high salt intake, maintains that dietary Na(+) is rapidly eliminated into urine, thereby achieving constant total-body Na(+) and water content. We introduced the reverse experimental approach by fixing salt intake of men participating in space flight simulations at 12 g, 9 g, and 6 g/day for months and tested for the predicted constancy in urinary excretion and total-body Na(+) content. At constant salt intake, daily Na(+) excretion exhibited aldosterone-dependent, weekly (circaseptan) rhythms, resulting in periodic Na(+) storage.

Body mass estimations for Plateosaurus engelhardti using laser scanning and 3D reconstruction methods.

Both body mass and surface area are factors determining the essence of any living organism. This should also hold true for an extinct organism such as a dinosaur. The present report discusses the use of a new 3D laser scanner method to establish body masses and surface areas of an Asian elephant (Zoological Museum of Copenhagen, Denmark) and of Plateosaurus engelhardti, a prosauropod from the Upper Triassic, exhibited at the Paleontological Museum in Tübingen (Germany).

Erythropoietin as a volume-regulating hormone: an integrated view.

The intravascular volume consists of 40% to 45% red cells. Their production is controlled predominantly by erythropoietin (EPO), a hormone that is secreted particularly when tissue hypoxia is present. Because of this high percentage of the total intravascular volume the question comes to mind that, in addition to hypoxia, can volume-regulation mechanisms, known to be responsible for the maintenance of plasma volume, modulate EPO secretion when the total vascular volume changes? Indeed, there is evidence that in situations in which the intravascular volume or specifically the intrathoracic volume is altered, EPO secretion is affected.

Anemia and erythropoietin in space flights.

Since the very early manned missions in space, a state of anemia associated with reduced erythropoietin levels and reduced plasma volume was disclosed. The reduction in red blood cell mass is driven by a process of selective hemolysis, which has been named neocytolysis. This phenomenon also occurs in people living at a high altitude who descend rapidly to sea level.

Differential expression of nitric oxide synthases (NOS 1-3) in human skeletal muscle following exercise countermeasure during 12 weeks of bed rest.

Adaptive changes of major body systems in astronauts during spaceflight can be simulated by strict anti-orthostatic head-down tilt (HDT) bed rest (BR), a ground-based microgravity (microG) model that provides a meaningful opportunity to study atrophy mechanisms and possible countermeasures under controlled experimental conditions. As nitric oxide (NO) signaling is linked to muscle activity, we investigated altered expression of the three major isoforms of nitric oxide synthase (NOS 1-3) at cellular compartments during prolonged HDT BR without (control group) and with resistance exercise interventions (exercise group) using a flywheel ergometer (FWE). Atrophy detected in mixed (fast-slow) m.

Hypertension, sodium retention, calcium excretion and osteopenia in Dahl rats.

Background: Salt-sensitive hypertension in the Dahl rat is associated with abnormalities in both calcium (Ca2+) and sodium (Na) homeostasis.

Objective: To test the hypothesis that salt-induced abnormal Ca(2+) handling in Dahl salt-sensitive (DSS) rats is associated with negative Ca(2+) balance and bone disease.

Methods: Ca(2+) excretion in acute and chronic Na(+) loading and electrolyte and water balance were determined by balance studies in Dahl salt-resistant (DSR) and salt-sensitive (DSS) rats fed 8 or 0.

Formation of edema and fluid shifts during a long-haul flight.

Background: More than 1.5 billion passengers travel by aircraft every year. Leg edema, as a sign of venous stasis, is a well-known problem among passengers during and after long-haul flights.

Osmotically inactive skin Na+ storage in rats.

Compared with age-matched men, women are resistant to the hypertensive effects of dietary NaCl; however, after menopause, the incidence of salt-sensitive hypertension is similar in women and men. We recently suggested that osmotically inactive Na+ storage contributes to the development of salt-sensitive hypertension. The connective tissues, including those immediately below the skin that may serve as a reservoir for osmotically inactive Na+ storage, are affected by menopause.

Austrian Moderate Altitude Study 2000 (AMAS 2000). The effects of moderate altitude (1,700 m) on cardiovascular and metabolic variables in patients with metabolic syndrome.

We investigated the changes in the cardiovascular system [resting blood pressure (BP) and heart rate (HR), measured by means of a 24-h ambulatory BP and a holter-electrocardiogram (ECG)], glycemic parameters, and lipid metabolism of subjects suffering from metabolic syndrome during a 3-week sojourn at 1,700 m in the Austrian Alps. A total of 22 male subjects with metabolic syndrome were selected. Baseline investigations were performed at Innsbruck (500 m above sea level).

Austrian Moderate Altitude Study (AMAS 2000) - fluid shifts, erythropoiesis, and angiogenesis in patients with metabolic syndrome at moderate altitude (congruent with 1700 m).

It was hypothesized that subjects with metabolic syndrome (hypertension, obesity, hyperlipidemia, diabetes mellitus): (1) develop measurable peripheral edema at moderate altitude and (2) might show differences on erythropoiesis, iron status and vascular endothelial growth factor (VEGF) in comparison to healthy subjects during and after a long-term stay (3-week exposure) at moderate altitude (congruent with 1700 m). Twenty-two male subjects with metabolic syndrome were selected. Baseline investigations (t1) were performed in Innsbruck (500 m).

Long-term sodium balance in humans in a terrestrial space station simulation study.

Background: Sodium accumulation has been considered to take place in the extracellular space, leading to water retention and weight gain. This traditional view has been questioned by recent studies that showed sodium accumulation in humans without expansion of the extracellular volume. We investigated sodium balance and its impact on body weight (BW) during a long-term balance study.

Voice monitoring to measure emotional load during short-term stress.

It is well known that there is a relationship between the voice the human emotional status. Previous studies have demonstrated that changes of fundamental frequency ( f(0)), in particular, have a significant relationship with emotional load. The aim of the present study was to investigate how f(0) changes in response to an unknown emotionally stressful task under real-life conditions.

Reduced osmotically inactive Na storage capacity and hypertension in the Dahl model.

Recent evidence suggested that Na can be stored in an osmotically inactive form. We investigated whether osmotically inactive Na storage is reduced in a rat model of salt-sensitive (SS) hypertension. SS and salt-resistant (SR) Dahl-Rapp rats as well as Sprague-Dawley (SD) rats were fed a high (8%)- or low (0.