18 research outputs found
Network topology of stable isotope interactions in a sub-arctic raptor guild
Predation is an ecologically important process, and intra-guild interactions may
substantially influence the ecological effects of predator species. Despite a rapid expansion
in the use of mathematical graph theory to describe trophic relations, network approaches
have rarely been used to study interactions within predator assemblages. Assemblages of
diurnal raptors are subject to substantial intra and interspecific competition. Here we used
the novel approach of applying analyses based on network topology to species-specific
data on the stable isotopes 13C and 15N in feathers to evaluate patterns of relative resource
utilization within a guild of diurnal raptors in northern Sweden. Our guild consisted of the
golden eagle (Aquila chrysaetos), the gyrfalcon (Falco rusticolus), the peregrine falcon
(Falco peregrinus) and the rough-legged buzzard (Buteo lagopus). We found a modular
trophic interaction structure within the guild, but the interactions were less nested than
expected by chance. These results suggest low redundancy and hence a strong ecological
importance of individual species. Our data also suggested that species were less connected
through intra-guild interactions than expected by chance. We interpret our results as a
convergence on specific isotope niches, and that body size and different hunting behaviour
may mediate competition within these niches. We finally highlight that generalist predators
could be ecologically important by linking specialist predator species with disparate
dietary niches.http://link.springer.com/journal/4422017-10-31hb2016Mammal Research InstituteZoology and Entomolog
Time constraints on magmatism, mineralisation and metamorphism at the Falun base metal sulphide deposit, Sweden, using UâPb geochronology on zircon and monazite
Experiences from implementing value-based healthcare at a Swedish University Hospital â a longitudinal interview study
Association between plasma concentrations of linoleic acid-derived oxylipins and the perceived pain scores in an exploratory study in women with chronic neck pain
Comparative metabolomics of muscle interstitium fluid in human trapezius myalgia : an in vivo microdialysis study
The mechanisms behind trapezius myalgia are unclear. Many hypotheses have been presented suggesting an altered metabolism in the muscle. Here, muscle microdialysate from healthy and myalgic muscle is analysed using metabolomics. Metabolomics analyse a vast number of metabolites, enabling a comprehensive explorative screening of the cellular processes in the muscle. Microdialysate samples were obtained from the shoulder muscle of healthy and myalgic subjects that performed a work and stress test. Samples from the baseline period and from the recovery period were analysed using gas chromatography-mass spectrometry (GC-MS) together with multivariate analysis to detect differences in extracellular content of metabolites between groups. Systematic differences in metabolites between groups were identified using multivariate analysis and orthogonal partial least square discriminate analysis (OPLS-DA). A complementary Mann-Whitney U test of group difference in individual metabolites was also performed. A large number of metabolites were detected and identified in this screening study. At baseline, no systematic differences between groups were observed according to the OPLS-DA. However, two metabolites, l-leucine and pyroglutamic acid, were significantly more abundant in the myalgic muscle compared to the healthy muscle. In the recovery period, systematic difference in metabolites between the groups was observed according to the OPLS-DA. The groups differed in amino acids, fatty acids and carbohydrates. Myristic acid and putrescine were significantly more abundant and beta-d-glucopyranose was significantly less abundant in the myalgic muscle. This study provides important information regarding the metabolite content, thereby presenting new clues regarding the pathophysiology of the myalgic muscle.Originally published in thesis in manuscript form.</p
The progression of doxorubicin-induced intestinal mucositis in rats
Chemotherapy-induced intestinal mucositis is a severe side effect contributing to reduced quality of life and premature death in cancer patients. Despite a high incidence, a thorough mechanistic understanding of its pathophysiology and effective supportive therapies are lacking. The main objective of this rat study was to determine how 10 mg/kg doxorubicin, a common chemotherapeutic, affected jejunal function and morphology over time (6, 24, 72, or 168 h). The secondary objective was to determine if the type of dosing administration (intraperitoneal or intravenous) affected the severity of mucositis or plasma exposure of the doxorubicin. Morphology, proliferation and apoptosis, and jejunal permeability of mannitol were examined using histology, immunohistochemistry, and single-pass intestinal perfusion, respectively. Villus height was reduced by 40% after 72 h, preceded at 24 h by a 75% decrease in proliferation and a sixfold increase in apoptosis. Villus height recovered completely after 168 h. Mucosal permeability of mannitol decreased after 6, 24, and 168 h. There were no differences in intestinal injury or plasma exposure after intraperitoneal or intravenous doxorubicin dosing. This study provides an insight into the progression of chemotherapy-induced intestinal mucositis and associated cellular mucosal processes. Knowledge from this in vivo rat model can facilitate development of preventive and supportive therapies for cancer patients