Activity of the right cardiac ventricle and metabolism in healthy persons during an orthostatic test after short term immobilization

A 15 minute orthostatic test was performed on healthy male volunteers under conditions of catheterization of the right ventricle of the heart and the radial (or brachial) artery before and after 5 day bedrest in an antiorthostatic position of the body (with the foot of the bed raised 4.5 degrees). The change to a vertical position after immobilization was attended by a more marked increase in the rate of cardiac contractions, an increase of max dp/dt pressure in the right ventricle, and a decrease of cardiac and stroke indices. The decrease of the cardiac index was compensated for, to a certain measure, by a further increase in the extraction and utilization of O2 by the tissues. The arterial blood pH did not change essentially, while the decrease in pCO2 and content of standard bicarbonate was more marked

Tree species richness affecting fine root biomass in European forests

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Prevention of bone mineral changes induced by bed rest: Modification by static compression simulating weight bearing, combined supplementation of oral calcium and phosphate, calcitonin injections, oscillating compression, the oral diophosphonatedisodium etidronate, and lower body negative pressure

The phenomenon of calcium loss during bed rest was found to be analogous to the loss of bone material which occurs in the hypogravic environment of space flight. Ways of preventing this occurrence are investigated. A group of healthy adult males underwent 24-30 weeks of continuous bed rest. Some of them were given an exercise program designed to resemble normal ambulatory activity; another subgroup was fed supplemental potassium phosphate. The results from a 12-week period of treatment were compared with those untreated bed rest periods. The potassium phosphate supplements prevented the hypercalciuria of bed rest, but fecal calcium tended to increase. The exercise program did not diminish the negative calcium balance. Neither treatment affected the heavy loss of mineral from the calcaneus. Several additional studies are developed to examine the problem further

The experience of taking methotrexate for juvenile idiopathic arthritis: results of a cross-sectional survey with children and young people

Background: Children and young people (CYP) with juvenile idiopathic arthritis (JIA) are known to have impaired health-related quality of life (HRQoL), which is improved significantly for many by treatment with methotrexate (MTX). However, a significant proportion of CYP experience difficulties in taking MTX, which may reduce its potential benefits for HRQoL. The aim of this research was to examine how CYP with JIA perceive MTX treatment and how this relates to HRQoL. Methods: CYP aged 8-16 years taking MTX for JIA completed an adapted Parent Adherence Report Questionnaire, which contains 100mm visual analogue scales, to assess difficulty taking MTX, adherence, frequency of negative reactions and helpfulness of MTX. They also completed the Pediatric Quality of Life Inventory (PedsQL) Generic and Rheumatology scales. We collected data on age, gender, JIA course, disease duration, MTX duration of use, route and dose. Number of inflamed and limited joints were indicators of disease severity. Results: 116 CYP participated. Most considered MTX helpful (median 87; interquartile range (IQR) 50.75–98) and reported adherence was high (median 98; IQR 90–100). There was greater variability on scores for difficulty (median 22; IQR 2–69) and frequency of negative reactions (median 14.5; IQR 1.25–80). Mean (S.D.) scores on the PedsQL Physical and Psychosocial subscales were 71.63 (24.02) and 71.78 (19.59) respectively, indicating poorer HRQoL than that reported by healthy children. After controlling for demographic and disease variables, poorer physical HRQoL was significantly accounted for by greater difficulty in taking MTX. Poorer psychosocial HRQoL was significantly accounted for by subcutaneous MTX administration, a lower rating of MTX helpfulness and a greater reported difficulty in taking MTX. Conclusions: Taking MTX for JIA was viewed as helpful by most CYP but HRQoL was poorer in those who reported greater difficulty in taking MTX

Chemical and physical properties of bulk aerosols within four sectors observed during TRACE-P

Chemical and physical aerosol data collected on the DC-8 during TRACE-P were grouped into four sectors based on back trajectories. The four sectors represent long-range transport from the west (WSW), regional circulation over the western Pacific and Southeast Asia (SE Asia), polluted transport from northern Asia with substantial sea salt at low altitudes (NNW) and a substantial amount of dust (Channel). WSW has generally low mixing ratios at both middle and high altitudes, with the bulk of the aerosol mass due to non-sea-salt water-soluble inorganic species. Low altitude SE Asia also has low mean mixing ratios in general, with the majority of the aerosol mass comprised of non-sea-salts, however, soot is also relatively important in this region. NNW had the highest mean sea salt mixing ratios, with the aerosol mass at low altitudes (\u3c2 km) evenly divided between sea salts, non-sea-salts, and dust. The highest mean mixing ratios of water-soluble ions and soot were observed at the lowest altitudes (\u3c2 km) in the Channel sector. The bulk of the aerosol mass exported from Asia emanates from Channel at both low and midaltitudes, due to the prevalence of dust compared to other sectors. Number densities show enhanced fine particles for Channel and NNW, while their volume distributions are enhanced due to sea salt and dust. Low-altitude Channel exhibits the highest condensation nuclei (CN) number densities along with enhanced scattering coefficients, compared to the other sectors. At midaltitudes (2–7 km), low mean CN number densities coupled with a high proportion of nonvolatile particles (≥65%) observed in polluted sectors (Channel and NNW) are attributed to wet scavenging which removes hygroscopic CN particles. Low single scatter albedo in SE Asia reflects enhanced soot

Spatial tethering of kinases to their substrates relaxes evolutionary constraints on specificity

Signal transduction proteins are often multi-domain proteins that arose through the fusion of previously independent proteins. How such a change in the spatial arrangement of proteins impacts their evolution and the selective pressures acting on individual residues is largely unknown. We explored this problem in the context of bacterial two-component signalling pathways, which typically involve a sensor histidine kinase that specifically phosphorylates a single cognate response regulator. Although usually found as separate proteins, these proteins are sometimes fused into a so-called hybrid histidine kinase. Here, we demonstrate that the isolated kinase domains of hybrid kinases exhibit a dramatic reduction in phosphotransfer specificity in vitro relative to canonical histidine kinases. However, hybrid kinases phosphotransfer almost exclusively to their covalently attached response regulator domain, whose effective concentration exceeds that of all soluble response regulators. These findings indicate that the fused response regulator in a hybrid kinase normally prevents detrimental cross-talk between pathways. More generally, our results shed light on how the spatial properties of signalling pathways can significantly affect their evolution, with additional implications for the design of synthetic signalling systems.National Science Foundation (U.S.) (CAREER Award)National Science Foundation (U.S.). Graduate Research Fellowship Progra