Specialized physiological studies in support of manned space flight

Research in aerospace medicine is presented. The reports discussed include: circulatory and respiratory transients during and after orthostasis and the effects of beta adrenergic blockade; the determination of total body water by an ethanol dilution method; and increased total respiratory conductance breathing 100% oxygen (forced oscillation method)

Specialized physiological studies in support of manned space flight

The effects of a diuretic (Lasix) induced dehydration on the cardiovascular and hematological responses to lower body negative pressure (LBNP) were analyzed and compared to previous observations on dehydration following exercise in the heat. During LBNP runs the subjects were monitored for changes in blood volume, heart rate, blood pressure, and variations in the volume of the left calf. It was concluded that Lasix dehydration produced a depletion of the body electrolytes at the expense of both the plasma and extravascular compartments. Striking differences were found between those subjects who were physically active (Runners: R) and those who did not engage in any regular physical activity (Non-runners: NR). Tolerance to LBNP (Torr x min) was significantly lower in the R's than the NR's before and after dehydration, however the R's lost more of their tolerance after dehydration with Lasix than after exercise in the heat for about the same fluid loss. The opposite was true for the NR's. Two factors appear to be responsible for the lower LBNP tolerance in R's: parasympathetic inhibition of cardiac activity during LBNP and a greater propensity to pool blood in the lower extremities

The repertory of bone marrow progenitor cells associated with lymphogenic metastasis in patients with invasive carcinoma of no special type

The high mortality of patients with breast cancer is determined by metastatic disease. It is thought that the metastatic disease development associated with the repertory of bone marrow progenitor cells in breast cancer patients. In our study the correlation between the bone marrow progenitor cells presences in the tumor and blood of patients and the lymphogenic metastasis development was studied. The main clinical and pathological parameters of 24 patients with invasive breast carcinoma of non-specific type were analyzed. Endothelial progenitor cells, mesenchymal stem cells, macrophage precursors, hematopoietic progenitor cells were detected with specific antibodies against CD34, CD133, CD90, VEGFR1, CD11b, CD45, CD202 in the cell-rich fluid from frozen tumor. The amount of MCP-1 in the patients blood serum was assessed by enzymelinked immunosorbent assay (ELISA), at a wavelength of 450 nm. The cytokines concentration was calculated from the calibration plot. The program package Statistica 10.0. was used for statistical data processing. The high risk of lymphogenic metastasis in patients who didn't complete a neoadjuvant chemotherapy course was associated with the number of HPC, EPC and MSC in tumor and MCP-1 in blood

No Impact of Body Mass Index on Outcome in Stroke Patients Treated with IV Thrombolysis BMI and IV Thrombolysis Outcome.

The impact of excess body weight on prognosis after stroke is controversial. Many studies report higher survival rates in obese patients ("obesity paradox"). Recently, obesity has been linked to worse outcomes after intravenous (IV) thrombolysis, but the number and sample size of these studies were small. Here, we aimed to assess the relationship between body weight and stroke outcome after IV thrombolysis in a large cohort study. In a prospective observational multicenter study, we analyzed baseline and outcome data of 896 ischemic stroke patients who underwent IV thrombolysis. Patients were categorized according to body mass index (BMI) as underweight (<18.5 kg/m2), normal weight (18.5-24.9 kg/m2), overweight (25-29.9 kg/m2), obese (30-34.9 kg/m2) or severely obese (>35 kg/m2). Using uni- and multivariate modeling, we assessed the relationship of BMI with favorable outcome (defined as modified Rankin Scale 0 or 1) and mortality 3 months after stroke as well as the occurrence of symptomatic intracerebral hemorrhages (sICH). We also measured the incidence of patients that had an early neurological improvement of >40% on the National Institutes of Health Stroke Scale (NIHSS) after 24 hours. Among 896 patients, 321 were normal weight (35.8%), 22 underweight (2.5%), 378 overweight (42.2%), 123 obese (13.7%) and 52 severely obese (5.8%). Three-month mortality was comparable in obese vs. non-obese patients (8.1% vs. 8.3%) and did not differ significantly among different BMI groups. This was also true for favorable clinical outcome, risk of sICH and early neurological improvement on NIHSS at 24 hours. These results remained unchanged after adjusting for potential confounding factors in the multivariate analyses. BMI was not related to clinical outcomes in stroke patients treated with IVT. Our data suggest that the current weight-adapted dosage scheme of IV alteplase is appropriate for different body weight groups, and challenge the existence of the obesity paradox after stroke

Specialized physiological studies in support of manned space flight

Subjects were tested for tolerance to lower body negative pressure (LBNP) before and after acute dehydration by working intermittenly for two hours without fluid replacement. On the second day there-after the LBNP tests were repeated before and after acute dehydration. The LBNP test consisted of 5 min long consective stages at -20, -30, -40, -50 and -60 Torr. Tests were terminated when syncope was imminent or the full sequence was completed. Tolerance was expressed in terms of cumulative stress in Torr x min. Measurements of body mass, density, fat fraction and total body water (TBW) were made before and after acclimation. Blood volume and its constituents were determined before and after each of the four LBNP tests. During LBNP, heart rate, blood pressure, and changes in calf and forearm volume were recorded every minute. Results showed: acute dehydration caused a significant loss in average LBNP tolerance on all subjects. Acclimation to heat did not significantly affect LBNP tolerance in hydrated subjects but significantly improved it on dehydrated subjects

Specialized physiological studies in support of manned space flight

The reversible changes that take place in the cardiovascular system during weightlessness were investigated. Particular attention was given to the assessment of cardiovascular functions during and after space missions. One of the most important of these functions is the amount of blood pumped by the heart per min at rest and during exercise of gravitational stress

Research report on: Specialized physiological studies in support of manned space flight

An investigation of the role of 02 fluctuations in oxygen uptake observed with changing posture is reported. A comparison of the closing volume test with other pulmonary function measurements is presented along with a comparison of hydrostatic weighing, and a stereophotogrammetric method for determining body volume

Monitoring and Pay: An Experiment on Employee Performance under Endogenous Supervision

We present an experimental test of a shirking model where monitoring intensity is endogenous and effort a continuous variable. Wage level, monitoring intensity and consequently the desired enforceable effort level are jointly determined by the maximization problem of the firm. As a result, monitoring and pay should be complements. In our experiment, between and within treatment variation is qualitatively in line with the normative predictions of the model under standard assumptions. Yet, we also find evidence for reciprocal behavior. Our data analysis shows, however, that it does not pay for the employer to solely rely on the reciprocity of employees

The changing nature of risk and risk management: the challenge of borders, uncertainty and resilience

No abstract available

How to return to subjectivity? Natorp, Husserl, and Lacan on the limits of reflection

This article discusses the recent call within contemporary phenomenology to return to subjectivity in response to certain limitations of naturalistic explanations of the mind. The meaning and feasibility of this call is elaborated by connecting it to a classical issue within the phenomenological tradition concerning the possibility of investigating the first-person perspective through reflection. We will discuss how this methodological question is respectively treated and reconfigured in the works of Natorp, Husserl, and Lacan. Finally, we will lay out some possible consequences of such a cross-reading for the conception of subjectivity and the concomitant effort to account for this dimension of first-person experience in response and in addition to its omission within the standard third-person perspective of psychological research