Effects of prolonged exercise at a similar percentage of maximal oxygen consumption in trained and untrained subjects

Six trained male cyclists and six untrained but physically active men participated in this study to test the hypothesis that the use of percentage maximal oxygen consumption (%VO2max) as a normalising independent variable is valid despite significant differences in the absolute VO2max of trained and untrained subjects. The subjects underwent an exercise test to exhaustion on a cycle ergometer to determine VO2max and lactate threshold. The subjects were grouped as trained (T) if their VO2max exceeded 60 ml.kg-1.min-1, and untrained (UT) if their VO2max was less than 50 ml.kg-1.min-1. The subjects were required to exercise on the ergometer for up to 40 min at power outputs that corresponded to approximately 50% and 70% VO2max. The allocation of each exercise session (50% or 70% VO2max) was random and each session was separated by at least 5 days. During these tests venous blood was taken 10 min before exercise (- 10 min), just prior to the commencement of exercise (0 min), after 20 min of exercise (20 min), at the end of exercise and 10 min postexercise (+ 10 min) and analysed for concentrations of cortisol, [Na+], [K+], [Cl-], glucose, free fatty acid, lactate [la-], [NH3], haemoglobin [Hb] and for packed cell volume. The oxygen consumption (VO2) and related variables were measured at two time intervals (14-15 and 34-35 min) during the prolonged exercise tests. Rectal temperature was measured throughout both exercise sessions. There was a significant interaction effect between the level of training and exercise time at 50% VO2max for heart rate (fc) and venous [la-].(ABSTRACT TRUNCATED AT 250 WORDS)     

Ion Transport in Isolated Rabbit Ileum : III. Chloride fluxes

Unidirectional Cl fluxes across in vitro segments of rabbit ileum have been determined both in the absence and in the presence of an electrochemical potential gradient. The results indicate that Cl transport in this preparation can be attributed to purely passive forces uninfluenced by solvent drag or exchange diffusion. Furthermore, on the basis of this and previous studies, it has been demonstrated that the sum of the partial ionic conductances of Na and Cl accounts for at least 90 per cent of the total tissue conductance.     

A Simple, Inexpensive Metabolism Cage for Small Mammals

By utilizing ordinary laboratory equipment and a spherical feces-urine separator, a simple, inexpensive metabolism cage for small mammals can be constructed. A hardware cloth animal cage over a cylindrical battery jar containing a spherical feces-urine separator affords the following advantages not commonly found in commercial metabolism cages: 1) complete separation of feces and urine through minimal contact, 2) minimal evaporation of urine due to proximity of storage vessel and lack of exogenous air currents, and 3) extremely low cost of less than five dollars. The metabolism cage is designed to allow measurement of fluid intake, and to separate and collect feces and urine for numerous qualitative and quantitative determinations. In addition, the metabolism cage permits observation of the animal, feces, and urine at all times, is readily cleaned or sterilized, and is easily fashioned from common laboratory equipment.     

Physicians' and nurses' retention of knowledge and skill after training in cardiopulmonary resuscitation.

Physicians and nurses in a community hospital who successfully completed the standard 1-day training program in basic life support cardiopulmonary resuscitation (CPR) were retested 6 and 12 months after training. Their perceptions of their knowledge of and skill in CPR were recorded along with an account of the roles they had taken in CPR incidents. The physicians and nurses initially had the same level of knowledge of CPR, but the physicians learned significantly more and retained it longer. After training, the nurses participated much more in CPR incidents, limiting themselves to basic life support functions. The physicians'' participation, however, remained at about the same level and was limited to advanced life support functions. By 12 months after training the scores in both groups were similar to the pretraining scores, which suggests that practice with feedback is necessary during the 1-year period before retraining and recertification. It may be that the two groups require different training programs.     

Development of Dipetalonema viteae third-stage larvae (Nematoda: Filarioidea) in micropore chambers implanted into jirds, hamsters, normal and immunized mice

Development of third-stage larvae of Dipetalonema viteae within subcutaneously implanted micropore chambers proceeded in all hosts tested up to the fourth-stage larvae and occasionally to adolescent worms. In the jird the timing of development was comparable to a natural infection. Although the mouse is an insusceptible host, larval development could take place, but was very slow. Two intraperitoneal inoculations of living third-stage larvae into mice induced the production of antibodies against the larval cuticle and against common antigens. In such immune mice the development of third- and fourth-stage larvae within micropore chambers was significantly inhibited, larval mortality was increased, and the larval motility was impaired.     

An assessment of the breeding range,colony sizes and population of the Westland petrel (Procellaria westlandica)

Abstract

The Westland petrel (Procellaria westlandica) is an endemic New Zealand species and one of the very few burrowing seabird species still breeding on mainland New Zealand. It nests only on a series of coastal ridgelines near to Punakaiki on the West Coast of the South Island. Between 2002 and 2005, surveys were undertaken at 28 of the 29 known colonies. The area occupied by the colonies was 73 ha; most colonies had fewer than 50 burrows, but six colonies had 201–500 burrows and four colonies had more than 1000 burrows. We find that the current breeding range of Westland petrel and the location of individual colonies are similar to those reported in both the 1950s and 1970s. Based on total burrow counts at 28 colonies and burrow occupancy rates determined by annual monitoring, the annual breeding population is estimated to be between 2954 and 5137 breeding pairs.     

Landscape context modulates alien plant invasion in Mediterranean forest edges

Natural habitats in human-altered landscapes are especially vulnerable to biological invasions, especially in their edges. We aim to understand the influence of landscape and local characteristics on biological invasions by exploring the level of plant invasion and alien species traits in forest edges in highly urbanized landscapes. We identified all plant species in 73 paired plots in the edge and 50 m towards the interior of the forest. We explored the association between alien species richness and similarity in species composition between edge and interior plots with landscape and local variables, using generalized linear models and variance partitioning techniques. Then, we performed Fourth-corner analyses to explore the association between alien plant traits and local and landscape variables. In contrast to native species richness, alien species richness was more affected by the surrounding landscape than by the local characteristics of the edge. Road proximity was positively associated with alien species richness and proportion and was its most important correlate, whereas disturbance was negatively associated with native species richness and was its most influential factor. Alien plant traits were also primarily associated with landscape characteristics. For instance, species of Mediterranean origin and introduced for agriculture were associated with higher agriculture use in the landscape. Our findings suggest that risk analyses of habitat vulnerability to invasion must consider the landscape context in order to successfully predict highly invaded areas and identify potentially successful invaders.     

Learned helplessness: unique features and translational value of a cognitive depression model

The concept of learned helplessness defines an escape or avoidance deficit after uncontrollable stress and is regarded as a depression-like coping deficit in aversive but avoidable situations. Based on a psychological construct, it ideally complements other stress-induced or genetic animal models for major depression. Because of excellent face, construct, and predictive validity, it has contributed to the elaboration of several pathophysiological concepts and has brought forward new treatment targets. Whereas learned helplessness can be modeled not only in a broad variety of mammals, but also in fish and Drosophila, we will focus here on the use of this model in rats and mice, which are today the most common species for preclinical in vivo research in psychiatry.