Temperature-Dependent Biomarkers of Estrogenic Exposure in a Piscivore Freshwater Fish.

The biological effects of endocrine-active compounds and increasing water temperatures as a result of climate change have been studied extensively and independently, but there is a dearth of research to examine the combined effect of these factors on exposed organisms. Recent data suggest that estrogenic exposure and rising ambient temperatures independently impact predator-prey relationships. However, establishing these connections in natural settings is complex. These obstacles can be circumvented if biomarkers of estrogenic exposure in resident fish can predict changes in predator-prey relationships. To test the effects of estrone and temperature, the piscivore bluegill sunfish (Lepomis macrochirus) was exposed for 30 days to estrone at concentrations (90 ± 17.6 ng/L [mean ± standard deviation] and 414 ± 146 ng/L) previously shown to reduce prey-capture success. Exposures were conducted at four temperatures (15 °C, 18 °C, 21 °C, 24 °C) to simulate breeding season ambient temperatures across the natural range of this species. A suite of morphological and physiological biomarkers previously linked to estrogenic exposures were examined. Biomarkers of estrone exposure were more commonly and severely impacted in male fish than in female fish. Notably, the gonadosomatic index was lower and gonads were less mature in exposed males. Additionally, temperature modulated the effects of estrone similarly in males and females with fish exposed at higher temperatures typically exhibiting a decreased morphological index. This study provides evidence that alterations in hepatic function and gonadal function may cause shifts in metabolism and energy allocation that may lead to declining prey capture performance.

Temperature and Estrogen Alter Predator-Prey Interactions between Fish Species.

A variety of environmental estrogens are commonly detected in human-impacted waterways. Although much is known about the effects of these environmental estrogens on the reproductive physiology and behavior of individuals within species, comparatively less is known about how these compounds alter the outcomes of interactions between species. Furthermore, few studies have considered how the effects of contaminants are modulated by natural variation in abiotic factors, such as temperature. To help fill this knowledge gap, we conducted a factorial experiment to examine the independent and combined effects of estrone (E1) and temperature on the outcome of predator-prey interactions between two common North American freshwater fishes, fathead minnows (Pimephales promelas) and bluegill sunfish (Lepomis macrochirus). Larval fathead minnows and adult sunfish were exposed to either a low (mean±standard deviation, 90.1 ± 18 ng/L; n = 16) or high (414 ± 147 ng/L; n = 15) concentration of E1 or to a solvent control for 30 days at one of four natural seasonal temperatures (15°C, 18°C, 21°C, and 24°C) before predation trials were performed. Exposure to E1 was associated with a significant increase in larval predation mortality that was independent of temperature. Across all temperature treatments, approximately 74% of control minnows survived; this survivorship significantly exceeded that of minnows exposed to either concentration of E1 (49% and 53% for minnows exposed to the low and high concentrations, respectively). However, exposure to E1 also impaired the prey-capture success of sunfish, partially mitigating predation pressure on exposed minnows. Overall prey-capture success by sunfish showed an inverted U-shaped distribution with temperature, with maximal prey consumption occurring at 21°C. This study illustrates the vulnerability of organismal interactions to estrogenic pollutants and highlights the need to include food web interactions in assessments of risk.

[Quality of life five years after total or partial knee arthroplasty]. / Lebensqualität von Patienten fünf Jahre nach Knie-Arthroplastik.

AIM: Multiple aspects of health-related quality of life were assessed in elderly patients after total or partial knee arthroplasty. METHOD: 187 subjects who had undergone knee arthroplasty 5 years ago were asked to fill out 3 questionnaires, the Nottingham Health Profile, the SF-36 Health Survey and the Funktionsfragebogen Hannover. Results were compared to standard data. The impact of gender and age was analyzed, and 3 different types of prostheses were compared. RESULTS: Response rate was 74 % (n = 138). Regarding the main symptoms pain and subjective function, as well as almost all other aspects, quality of life proved to be significantly reduced compared to the age-matched general population. Correlations between age and quality of life scales were low. Different types of implants led to similar results in all scales but one. CONCLUSION: 5 years after knee arthroplasty the quality of life is markedly reduced compared to the general population. The impact of age, gender, and type of implant is low. In our sample, the SF-36 showed methodological advantages compared to the NHP for the measurement of subjective pain and function.

[Principle of solid-frequent oscillo-resistometry]. / Prinzip der festfrequenten Oszillo-Resistometrie.

A small device for the oscillatory measurement of both respiratory resistance and residual volume (SIRE-GNOST FD5), introduced in the late 70ies, found wide-spread use. It is working with a constant frequency of 10 Hz and uses a simple signal conditioning to combine the two components of the "complex" respiratory impedance into a single parameter "Ros", thus allowing to plot e.g. Resistance-Volume-Curves.

A direct-display oscillation method for measurement of respiratory impedance.

The basic principle of the method described here is derived from a variant of the oscillation method. A reference impedance is connected to the mouth; between these two an oscillating flow is imposed. As a reference impedance we use a flexible tube, which acts as a virtually pure inductance or inertance. Respiration is hardly impeded. The only measured parameter is the alternating pressure in front of the mouth and this is easily picked up by a simple microphone. In contrast to former direct-display methods, the inertia and elasticity of the respiratory gas and the respiratory tract, i.e., airways including lungs and thorax, are also taken into account for the evaluation. The respiratory resistance is studied as a complex parameters, i.e., as an impedance. With the aid of diagrams or via electronic computation circuitry, the direct and continuous display of all impedance components such as its magnitude and phase, resistance, and reactance is possible. They can be read out as a function of time, respiratory flow, or volume.

[Oscillatory determination of functional residual capacity (FRC)]. / Oszillatorische Bestimmung der funktionellen Residualkapazität (FRC).

The washing-in of a low density gas (80% He, 20% O2) into the lung is being eased by greater diffusibility and diminished work of breathing. Helium analysis was performed by means of the oscillation method with an equipment suitable for the assessment of resistance to breathing. The density of helium gas mixture is being compared to the density of ambient air.