117 research outputs found

    Fungus Cultivation by Ambrosia Beetles: Behavior and Laboratory Breeding Success in Three Xyleborine Species

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    Fungus cultivation by ambrosia beetles is one of the four independently evolved cases of agriculture known in animals. Such cultivation is most advanced in the highly social subtribe Xyleborina (Scolytinae), which is characterized by haplodiploidy and extreme levels of inbreeding. Despite their ubiquity in forests worldwide, the behavior of these beetles remains poorly understood. This may be in part because of their cryptic life habits within the wood of trees. Here we present data obtained by varying a laboratory breeding technique based on artificial medium inside glass tubes, which enables behavioral observations. We studied species of the three most widespread genera of Xyleborina in the temperate zone: Xyleborus, Xyleborinus, and Xylosandrus. We raised several generations of each species with good breeding success in two types of media. The proportion of females of Xyleborinus saxesenii Ratzeburg producing offspring within 40 d depended significantly on founder female origin, which shows a transgenerational effect. Labor-intensive microbial sterilization techniques did not increase females' breeding success relative to a group of females shortly treated with ethanol. Gallery productivity measured as the mean number of mature offspring produced after 40 d varied between species and was weakly affected by the type of medium used and foundress origin (field or laboratory) in X. saxesenii, whereas different preparation and sterilization techniques of the beetles had no effect. Behavioral observations showed the time course of different reproductive stages and enabled to obtain detailed behavioral information in all species studied. We propose that the laboratory techniques we describe here are suited for extensive studies of sociality and modes of agriculture in the xyleborine ambrosia beetles, which may yield important insights into the evolution of fungal agriculture and advanced social organizatio

    Hemodynamic effects of nitroglycerin in an experimental model of acute aortic regurgitation

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    AbstractAfterload reduction is an accepted therapeutic modality for the treatment of congestive heart failure caused by chronic aortic regurgitation. However, the role of vasodilator therapy in acute aortic incompetence has not been established. To investigate this, left ventricular volume overload was produced in 18 dogs by constructing a valved conduit from the descending thoracic aorta to the left ventricular apex. The time course of aortic, pulmonary and conduit flows was analyzed in eight control studies and established stability of the experimental model.In the remaining 10 dogs, intravenous nitroglycerin, titrated to reduce mean aortic blood pressure by 40%, and placebo (ethanol) were each infused for 20 min periods. Compared with placebo, nitroglycerin significantly reduced aortic flow (3,945 ± 324 to 3,397 ± 362 ml/min, p < 0.01), regurgitant flow (1,304 ± 131 to 764 ± 90 ml/min, p < 0.001), septal-lateral end-diastolic diameter (47.5 ± 1.8 to 46.5 ± 1.8 mm, p < 0.001), left ventricular end-diastolic pressure (6.9 ± 0.8 to 6.0 ± 0.6 mm Hg, p < 0.05), left ventricular stroke work (19.0 ± 2.6 to 10.8 ± 1.7 g-m/beat, p < 0.001) and systemic vascular resistance (2,253 ± 173 to 1,433 ± 117 dyne-s/cm5, p < 0.001). In contrast, pulmonary flow, left anterior descending coronary flow and subendocardial pH did not change during infusion of either nitroglycerin or placebo.These data indicate that by decreasing preload and afterload, and by preserving coronary flow and tissue pH, nitroglycerin effectively reduced ventricular and regurgitant volumes in the setting of acute volume overload. This study supports the clinical use of nitroglycerin in severe acute aortic incompetence

    Serum N-Terminal propeptide of collagen type I is associated with the number of bone Metastases in breast and prostate cancer and correlates to other bone related markers

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    Background A number of biomarkers have been proven potentially useful for their ability to indicate bone metastases (BM) in cancer patients. The aim of this study was to investigate the relative utility of a newly developed N-terminal propeptide of collagen type I (PINP) human serum assay for the detection of BM in cancer patients. This assay has a corresponding rat PINP assay which in the future might help in translational science between rodent and human trials. Methods Participants were 161 prostate, lung and breast cancer patients stratified by number of BM(Soloway score). PINP was assessed and correlated to number of BM. Additionally, the PINP marker was correlated to bone resorption of young (ALPHA CTX-I)- and aged bone (BETA CTX-I); number of osteoclasts (Tartrate-resistant acid phosphatase 5b, TRACP5B) and osteoclast activity (CTX-I/TRACP5B). Results PINP was significantly elevated in breast- and prostate cancer patients +BM, compared to –BM ( P < 0.001), however not in lung cancer patients. A strong linear association was seen between PINP and the number of BMs. Significant elevation of PINP was observed at Soloway scores 1–4 (<0 BM) compared with score 0 (0 BM) ( P < 0.001). The correlation between bone resorption of young bone or aged bone and bone formation was highly significant in patients +BM and –BM ( P < 0.0001). Conclusions Data suggest that the present PINP potentially could determine skeletal involvement in patients with breast or prostate cancer. Correlations suggested that coupling between bone resorption and bone formation was maintained in breast- and prostate cancer patients

    Cross-Attraction between an Exotic and a Native Pine Bark Beetle: A Novel Invasion Mechanism?

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    Aside from the ecological impacts, invasive species fascinate ecologists because of the unique opportunities that invasives offer in the study of community ecology. Some hypotheses have been proposed to illustrate the mechanisms that allow exotics to become invasive. However, positive interactions between exotic and native insects are rarely utilized to explain invasiveness of pests.Here, we present information on a recently formed association between a native and an exotic bark beetle on their shared host, Pinus tabuliformis, in China. In field examinations, we found that 35-40% of P. tabuliformis attacked by an exotic bark beetle, Dendroctonus valens, were also attacked by a native pine bark beetle, Hylastes parallelus. In the laboratory, we found that the antennal and walking responses of H. parallelus to host- and beetle-produced compounds were similar to those of the exotic D. valens in China. In addition, D. valens was attracted to volatiles produced by the native H. parallelus.We report, for the first time, facilitation between an exotic and a native bark beetle seems to involve overlap in the use of host attractants and pheromones, which is cross-attraction. The concept of this interspecific facilitation could be explored as a novel invasive mechanism which helps explain invasiveness of not only exotic bark beetles but also other introduced pests in principle. The results reported here also have particularly important implications for risk assessments and management strategies for invasive species

    The additional value of patient-reported health status in predicting 1-year mortality after invasive coronary procedures: A report from the Euro Heart Survey on Coronary Revascularisation

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    Objective: Self-perceived health status may be helpful in identifying patients at high risk for adverse outcomes. The Euro Heart Survey on Coronary Revascularization (EHS-CR) provided an opportunity to explore whether impaired health status was a predictor of 1-year mortality in patients with coronary artery disease (CAD) undergoing angiographic procedures. Methods: Data from the EHS-CR that included 5619 patients from 31 member countries of the European Society of Cardiology were used. Inclusion criteria for the current study were completion of a self-report measure of health status, the EuroQol Questionnaire (EQ-5D) at discharge and information on 1-year follow-up, resulting in a study population of 3786 patients. Results: The 1-year mortality was 3.2% (n = 120). Survivors reported fewer problems on the five dimensions of the EQ-5D as compared with non-survivors. A broad range of potential confounders were adjusted for, which reached a p<0.10 in the unadjusted analyses. In the adjusted analyses, problems with self-care (OR 3.45; 95% CI 2.14 to 5.59) and a low rating (≤ 60) on health status (OR 2.41; 95% CI 1.47 to 3.94) were the most powerful independent predictors of mortality, among the 22 clinical variables included in the analysis. Furthermore, patients who reported no problems on all five dimensions had significantly lower 1-year mortality rates (OR 0.47; 95% CI 0.28 to 0.81). Conclusions: This analysis shows that impaired health status is associated with a 2-3-fold increased risk of all-cause mortality in patients with CAD, independent of other conventional risk factors. These results highlight the importance of including patients' subjective experience of their own health status in the evaluation strategy to optimise risk stratification and management in clinical practice

    Sulfonylureas and ischaemic preconditioning: a double-blind, placebo-controlled evaluation of glimepiride and glibenclamide

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    Aims Glimepiride is a new sulfonylurea for diabetes treatment which is supposed to impact less on extra-pancreatic ATP-dependent K+channels than the conventional drug glibenclamide. This study was performed to evaluate whether this results in a better maintenance of ATP-dependent K+channel mediated ischaemic myocardial preconditioning. Methods and Results In a double-blind placebo-controlled study the period of total coronary occlusion during balloon angioplasty of high grade coronary artery stenoses was used as a model to compare the effects of both drugs. Quantification of myocardial ischaemia was achieved by recording the intracoronary ECG and the time to the occurrence of angina during vessel occlusion. All patients underwent three dilatations. The first dilatation (dilatation 1) served to determine the severity of ischaemia during vessel occlusion. During dilatation 2, baseline values were recorded. Thereafter, glimepiride (15 patients: 1·162mg), glibenclamide (15 patients: 2·54mg) or placebo (15 patients) were intravenously administered over 12min. Dilatation 3 started 10min after the beginning of the drug administration. Mean ST segment shifts in the placebo group decreased by 35% (dilatation 2: 0·23; dilatation 3: 0·15mV; CI −0·55 to 0·00mV;P=0·049). A similar reduction also occurred in the glimepiride group, in which repetitive balloon occlusion led to a 34% reduction (dilatation 2: 0·35; dilatation 3: 0·23mV; CI −0·21 to −0·02mV;P=0·01). There was little influence however, on mean ST segment shifts in the glibenclamide group (dilatation 2 and dilatation 3: 0·24mV; CI −0·10 to 0·25mV;P=0·34). Accordingly, time to angina during balloon occlusion slightly increased (by 30%) in the placebo group (dilatation 2: 37s; dilatation 3: 48s; CI 0·0 to 15·0s;P=0·16); increased by 13% in the glimepiride group (dilatation 2: 40s; dilatation 3: 45s; CI 0·0 to 14·0s;P=0·023); and remained unchanged in the glibenclamide group (dilatation 2 and dilatation 3: 30s; CI −7·5 to 7·5s;P=0·67). Conclusion These results show that glimepiride maintains myocardial preconditioning, while glibenclamide might be able to prevent i
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