Thoracoabdominal restriction in supine men: CT and lung function measurements

Thoracoabdominal restriction was brought on by means of a corset, and the subsequent effects on thoracic dimensions and lung tissue were studied by computerized tomography (CT) and by various lung function tests in supine healthy volunteers (mean age 30 yr). Restriction caused reductions in total lung capacity (helium equilibration) from mean 6.84 to 4.80 liters, in functional residual capacity (FRC) from 2.65 to 2.08 liters, and in vital capacity from 5.16 to 3.45 liters. Closing capacity (single-breath N2 washout) fell from 2.42 to 1.88 liters, thus matching the reduction in FRC. The static pressure-lung volume curve was shifted to the right by 1.5 cmH2O at 50% of total lung capacity. However, no change in the slope of the curve was observed. The diaphragm was moved cranially by 1.2 cm, and the thoracic cross-sectional area was reduced by a mean 32 cm2 at a level just above the diaphragm. No changes in the lung tissue were seen on CT scanning. Gas exchange, as assessed by multiple inert gas elimination technique and arterial blood gas analysis, was unaffected by restriction. It is concluded that in supine subjects, thoracoabdominal restriction that reduces FRC by 0.6 liter is not accompanied by atelectasis (normal CT scan). In this respect the result differs from that found in anesthetized supine subjects who show the same fall in FRC and atelectasis in dependent lung regions.     

Tauchbeobachtungen an Plankton und an Echostreuschichten

Zusammenfassung 1. Das Tauchen als Methode zur Untersuchung von Plankton und Echostreuschichten wird durch vier Beispiele erläutert: (a) Visuelle Beobachtungen an Wasserschichtungen und Grenzschichten durch Schwimmtaucher. (b) Untersuchung von Echostreuschichten durch Freitaucher, wobei sich ergab, daß angesammeltes biogenes Material in den untersuchten Sprung- beziehungsweise Streuschichten die Schallreflektion nicht beeinflußt. (c) Beobachtung von Großplankton und Feststellung von Planktonund Sestonkonzentrationen beim Tauchen mit dem Bathyscaph. (d) Untersuchung der Tiefenstreuschicht (deep scattering layer) durch Beobachtung der Vertikalwanderung bestimmter Arten des Großplanktons mit den Tauchbooten Bathyscaph und Soucoupe Plongeante. Physonectide Siphonophoren und Myctophiden standen in deutlicher Beziehung zur Tiefenstreuschicht und wurden als Echogeber erkannt.2. Die Möglichkeiten, von Tauchbooten aus quantitative und qualitative Proben von Plankton und auch vom Benthos zu nehmen, sind zur Zeit noch unzureichend. Die Entwicklung entsprechender Geräte für den wahlweisen und mehrfachen Einsatz bei demselben Tauchgang wird empfohlen.

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Diving observations on plankton and on scattering layers

Diving techniques are employed as a research tool in plankton investigations carried out in shallow water of the western Baltic Sea. Observations and samplings were made by skin divers on scattering layers corresponding to the discontinuity layers. Biogene materials, sometimes concentrated at the thermocline, are not responsible for this special kind of scattering, but rather discontinuity of salinity and temperature (Lenz 1965). For observations in deep water the use of undersea vehicles is recommended. From the Bathyscaph and the diving saucer, single plankton organisms and plankton concentrations were observed (e. g.Bernard 1958); investigations on the deep scattering layer have shown physonectid siphonophores and myctophids to be scatterers (Barham 1966). The equipment for sampling plankton and benthos from undersea vehicles is poorly developed. We need urgently gear for quantitative and qualitative sampling and for manifold use during single dives, i. e., multiple sampling gear and magazins for storage of samples.

     

Human proximity and habitat fragmentation are key drivers of the rangewide bonobo distribution

Habitat loss and hunting threaten bonobos (Pan paniscus), Endangered (IUCN) great apes endemic to lowland rainforests of the Democratic Republic of Congo. Conservation planning requires a current, data-driven, rangewide map of probable bonobo distribution and an understanding of key attributes of areas used by bonobos. We present a rangewide suitability model for bonobos based on a maximum entropy algorithm in which data associated with locations of bonobo nests helped predict suitable conditions across the species’ entire range. We systematically evaluated available biotic and abiotic factors, including a bonobo-specific forest fragmentation layer (forest edge density), and produced a final model revealing the importance of simple threat-based factors in a data poor environment. We confronted the issue of survey bias in presence-only models and devised a novel evaluation approach applicable to other taxa by comparing models built with data from geographically distinct sub-regions that had higher survey effort. The model’s classification accuracy was high (AUC = 0.82). Distance from agriculture and forest edge density best predicted bonobo occurrence with bonobo nests more likely to occur farther from agriculture and in areas of lower edge density. These results suggest that bonobos either avoid areas of higher human activity, fragmented forests, or both, and that humans reduce the effective habitat of bonobos. The model results contribute to an increased understanding of threats to bonobo populations, as well as help identify priority areas for future surveys and determine core bonobo protection areas.     

The degradation of nucleotide triphosphates extracted under boiling ethanol conditions is prevented by the yeast cellular matrix

Introduction

Boiling ethanol extraction is a frequently used method for metabolomics studies of biological samples. However, the stability of several central carbon metabolites, including nucleotide triphosphates, and the influence of the cellular matrix on their degradation have not been addressed.

Objectives

To study how a complex cellular matrix extracted from yeast (Saccharomyces cerevisiae) may affect the degradation profiles of nucleotide triphosphates extracted under boiling ethanol conditions.

Methods

We present a double-labelling LC–MS approach with a ¹³C-labeled yeast cellular extract as complex surrogate matrix, and ¹³C¹⁵N-labeled nucleotides as internal standards, to study the effect of the yeast matrix on the degradation of nucleotide triphosphates.

Results

While nucleotide triphosphates were degraded to the corresponding diphosphates in pure solutions, degradation was prevented in the presence of the yeast matrix under typical boiling ethanol extraction conditions.

Conclusions

Extraction of biological samples under boiling ethanol extraction conditions that rapidly inactivate enzyme activity are suitable for labile central energy metabolites such as nucleotide triphosphates due to the stabilizing effect of the yeast matrix. The basis of this phenomenon requires further study.

Graphical abstract

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Effects of various squalene epoxides on coenzyme Q and cholesterol synthesis

2,3-Oxidosqualene is an intermediate in cholesterol biosynthesis and 2,3:22,23-dioxidosqualene act as the substrate for an alternative pathway that produces 24(S),25-epoxycholesterol which effects cholesterol homeostasis. In light of our previous findings concerning the biological effects of certain epoxidated all-trans-polyisoprenes, the effects of squalene carrying epoxy moieties on the second and third isoprene residues were investigated here. In cultures of HepG2 cells both monoepoxides of squalene and one of their hydrolytic products inhibited cholesterol synthesis and stimulated the synthesis of coenzyme Q (CoQ). Upon prolonged treatment the cholesterol content of these cells and its labeling with [³H]mevalonate were reduced, while the amount and labeling of CoQ increased. Injection of the squalene monoepoxides into mice once daily for 6 days elevated the level of CoQ in their blood, but did not change the cholesterol level. The same effects were observed upon treatment of apoE-deficient mice and diabetic GK-rats. This treatment increased the hepatic level of CoQ10 in mice, but the amount of CoQ9, which is the major form, was unaffected. The presence of the active compounds in the blood was supported by the finding that cholesterol synthesis in the white blood cells was inhibited. Since the ratio of CoQ9/CoQ10 varies depending on the experimental conditions, the cells were titrated with substrate and inhibitors, leading to the conclusion that the intracellular isopentenyl-PP pool is a regulator of this ratio. Our present findings indicate that oxidosqualenes may be useful for stimulating both the synthesis and level of CoQ both in vitro and in vivo.     

Seasonal Changes in Osmotic and Ionic Regulation in Arctic Charr, Salvelinus Alpinus, From a High- and a Sub-arctic Anadromous Population

Seasonal changes in hypoosmoregulatory capacity were studied in hatchery-reared offspring of a high-Arctic strain of anadromous Arctic charr, Salvelinus alpinus, from Svalbard (79°N) and a sub-Arctic strain from Hammerfest, north Norway (70°N). The fish were held in freshwater under simulated, natural light conditions (Tromsø, 69°N) and natural water temperatures, and hypoosmoregulatory capacity was determined by seawater challenge tests between February and November. An improved hypoosmoregulatory capacity was seen in both strains at the time when their wild conspecifics migrate to the sea. The time when maximum hypoosmoregulatory capacity was achieved differed significantly between the two strains, suggesting that there may be genetic differences between the two populations in how environmental cues (e.g. temperature, photoperiod) entrain the development of seawater tolerance. The development and loss of hypoosmoregulatory capacity seemed to be more rapid and abrupt in the Svalbard charr than in the Hammerfest charr. This is hypothesised to be an adaptation to the stochastic and unpredictable variations in the time when the fish are allowed to migrate in the high-Arctic, and the need to prevent migration in years when the ice break occurs very late.     

Modeling preindustrial ANC and pH during the spring flood in northern Sweden

The natural preindustrial ANC and pH decline associated with 22 melt events from 11 streams during spring flood of 1997 and 1998 in Northern Sweden have been assessed using the Boreal Dilution Model (BDM). The results show that the spring flood pH decline of 0.5 to 2.5 pH units in the streams was largely caused by natural processes. The most important driving factors influencing pH were TOC increase in combination with ANC dilution. The study also demonstrates that pH in some streams can decline to pH values close to 4.5 as a result of natural processes alone. In general the anthropogenic component of the pH decline was between 0.1 and 0.3 pH units superimposed on the natural pH decline. Furthermore, the anthropogenic contribution to ANC and pH decline generally followed the gradient of anthropogenic S deposition in the region. The sites with the greatest inferred anthropogenic influence are also those for which the assumptions used in the BDM were most sensitive. Nevertheless, the results from this study suggest that the regional impact of anthropogenic acid deposition on the ANC and pH in northern Sweden is currently limited.