451 research outputs found
Myocardial Dysfunction in an Animal Model of Cancer Cachexia
Aims Fatigue is a common occurrence in cancer patients regardless of tumor type or anti-tumor therapies and is an especially problematic symptom in persons with incurable tumor disease. In rodents, tumor-induced fatigue is associated with a progressive loss of skeletal muscle mass and increased expression of biomarkers of muscle protein degradation. The purpose of the present study was to determine if muscle wasting and expression of biomarkers of muscle protein degradation occur in the hearts of tumor-bearing mice, and if these effects of tumor growth are associated with changes in cardiac function. Main methods The colon26 adenocarcinoma cell line was implanted into female CD2F1 mice and skeletal muscle wasting, in vivo heart function, in vitro cardiomyocyte function, and biomarkers of muscle protein degradation were determined. Key findings Expression of biomarkers of protein degradation were increased in both the gastrocnemius and heart muscle of tumor-bearing mice and caused systolic dysfunction in vivo. Cardiomyocyte function was significantly depressed during both cellular contraction and relaxation. Significance These results suggest that heart muscle is directly affected by tumor growth, with myocardial function more severely compromised at the cellular level than what is observed using echocardiography
Opioid-induced glial activation: mechanisms of activation and implications for opioid analgesia, dependence, and reward
Ā© 2007 with author. Published by TheScientificWorldThis review will introduce the concept of toll-like receptor (TLR)-mediated glial activation as central to all of the following: neuropathic pain, compromised acute opioid analgesia, and unwanted opioid side effects (tolerance, dependence, and reward). Attenuation of glial activation has previously been demonstrated both to alleviate exaggerated pain states induced by experimental pain models and to reduce the development of opioid tolerance. Here we demonstrate that selective acute antagonism of TLR4 results in reversal of neuropathic pain as well as potentiation of opioid analgesia. Attenuating central nervous system glial activation was also found to reduce the development of opioid dependence, and opioid reward at a behavioral (conditioned place preference) and neurochemical (nucleus accumbens microdialysis of morphine-induced elevations in dopamine) level of analysis. Moreover, a novel antagonism of TLR4 by (+)- and (-)-isomer opioid antagonists has now been characterized, and both antiallodynic and morphine analgesia potentiating activity shown. Opioid agonists were found to also possess TLR4 agonistic activity, predictive of glial activation. Targeting glial activation is a novel and as yet clinically unexploited method for treatment of neuropathic pain. Moreover, these data indicate that attenuation of glial activation, by general or selective TLR antagonistic mechanisms, may also be a clinical method for separating the beneficial (analgesia) and unwanted (tolerance, dependence, and reward) actions of opioids, thereby improving the safety and efficacy of their use.Mark R. Hutchinson, Sondra T. Bland, Kirk W. Johnson, Kenner C. Rice, Steven F. Maier, and Linda R. Watkin
The multifunctional CaĀ²āŗ/calmodulin-dependent protein kinase II delta (CaMKIIĪ“) phosphorylates cardiac titinās spring elements
Titin-based passive stiffness is post-translationally regulated by several kinases that phosphorylate specific spring elements located within titin's elastic I-band region. Whether titin is phosphorylated by calcium/calmodulin dependent protein kinase II (CaMKII), an important regulator of cardiac function and disease, has not been addressed. The aim of this work was to determine whether CaMKIIĪ“, the predominant CaMKII isoform in the heart, phosphorylates titin, and to use phosphorylation assays and mass spectrometry to study which of titin's spring elements might be targeted by CaMKIIĪ“. It was found that CaMKIIĪ“ phosphorylates titin in mouse LV skinned fibers, that the CaMKIIĪ“ sites can be dephosphorylated by protein phosphatase 1 (PP1), and that under baseline conditions, in both intact isolated hearts and skinned myocardium, about half of the CaMKIIĪ“ sites are phosphorylated. Mass spectrometry revealed that both the N2B and PEVK segments are targeted by CaMKIIĪ“ at several conserved serine residues. Whether phosphorylation of titin by CaMKIIĪ“ occurs in vivo, was tested in several conditions using back phosphorylation assays and phospho-specific antibodies to CaMKIIĪ“ sites. Reperfusion following global ischemia increased the phosphorylation level of CaMKIIĪ“ sites on titin and this effect was abolished by the CaMKII inhibitor KN-93. No changes in the phosphorylation level of the PEVK element were found suggesting that the increased phosphorylation level of titin in IR (ischemia reperfusion) might be due to phosphorylation of the N2B element. The findings of these studies show for the first time that titin can be phosphoryalated by CaMKIIĪ“, both in vitro and in vivo, and that titin's molecular spring region that determines diastolic stiffness is a target of CaMKIIĪ“.Centro de Investigaciones Cardiovasculare
Pre-Diagnostic Circulating Vitamin D and Risk of Melanoma in Men
PURPOSE: Various studies have examined the association between serum vitamin D levels and different cancers; however, this is the first prospective study of this association with melanoma risk. The aim of this study is to investigate the association between serum vitamin D [25(OH)D] levels and melanoma in a cohort of older, middle-aged Finnish male smokers. METHODS: We conducted a nested case-control study within the Alpha-Tocopherol Beta-Carotene Cancer Prevention (ATBC) Study. From the ATBC cohort, 368 subjects were chosen for our study; 92 participants that developed melanoma and 276 matched control subjects. At study baseline, lifestyle questionnaires and blood samples were collected. Serum 25(OH)D was modeled as three sets of categorical variables: clinically-defined categories, season-specific quartiles and season-adjusted residual quartiles. Conditional logistic regression was used to obtain odds ratios (ORs) and 95% confidence intervals (95% CIs) to estimate the association between circulating vitamin D and melanoma risk. RESULTS: Overall no association of serum 25(OH)D and melanoma risk was observed. A decreased risk of developing melanoma was observed in the middle categories compared to the lowest category, albeit not significant. CONCLUSION: Results indicate no association between serum 25(OH)D levels and melanoma. Additional studies, including possibly consortium efforts, are needed to investigate the association between serum 25(OH)D levels and risk of melanoma in larger, more diverse study populations
Systemic Maternal Inflammation and Neonatal Hyperoxia Induces Remodeling and Left Ventricular Dysfunction in Mice
The impact of the neonatal environment on the development of adult cardiovascular disease is poorly understood. Systemic maternal inflammation is linked to growth retardation, preterm birth, and maturation deficits in the developing fetus. Often preterm or small-for-gestational age infants require medical interventions such as oxygen therapy. The long-term pathological consequences of medical interventions on an immature physiology remain unknown. In the present study, we hypothesized that systemic maternal inflammation and neonatal hyperoxia exposure compromise cardiac structure, resulting in LV dysfunction during adulthood.Pregnant C3H/HeN mice were injected on embryonic day 16 (E16) with LPS (80 Āµg/kg; i.p.) or saline. Offspring were placed in room air (RA) or 85% O(2) for 14 days and subsequently maintained in RA. Cardiac echocardiography, cardiomyocyte contractility, and molecular analyses were performed. Echocardiography revealed persistent lower left ventricular fractional shortening with greater left ventricular end systolic diameter at 8 weeks in LPS/O(2) than in saline/RA mice. Isolated cardiomyocytes from LPS/O(2) mice had slower rates of contraction and relaxation, and a slower return to baseline length than cardiomyocytes isolated from saline/RA controls. Ī±-/Ī²-MHC ratio was increased and Connexin-43 levels decreased in LPS/O(2) mice at 8 weeks. Nox4 was reduced between day 3 and 14 and capillary density was lower at 8 weeks of life in LPS/O(2) mice.These results demonstrate that systemic maternal inflammation combined with neonatal hyperoxia exposure induces alterations in cardiac structure and function leading to cardiac failure in adulthood and supports the importance of the intrauterine and neonatal milieu on adult health
Understanding Plant-Microbe Interactions for Phytoremediation of Petroleum-Polluted Soil
Plant-microbe interactions are considered to be important processes determining
the efficiency of phytoremediation of petroleum pollution, however relatively
little is known about how these interactions are influenced by petroleum
pollution. In this experimental study using a microcosm approach, we examined
how plant ecophysiological traits, soil nutrients and microbial activities were
influenced by petroleum pollution in Phragmites australis, a
phytoremediating species. Generally, petroleum pollution reduced plant
performance, especially at early stages of plant growth. Petroleum had negative
effects on the net accumulation of inorganic nitrogen from its organic forms
(net nitrogen mineralization (NNM)) most likely by decreasing the inorganic
nitrogen available to the plants in petroleum-polluted soils. However, abundant
dissolved organic nitrogen (DON) was found in petroleum-polluted soil. In order
to overcome initial deficiency of inorganic nitrogen, plants by dint of high
colonization of arbuscular mycorrhizal fungi might absorb some DON for their
growth in petroleum-polluted soils. In addition, through using a real-time
polymerase chain reaction method, we quantified hydrocarbon-degrading bacterial
traits based on their catabolic genes (i.e. alkB (alkane
monooxygenase), nah (naphthalene dioxygenase) and
tol (xylene monooxygenase) genes). This enumeration of
target genes suggests that different hydrocarbon-degrading bacteria experienced
different dynamic changes during phytoremediation and a greater abundance of
alkB was detected during vegetative growth stages. Because
phytoremediation of different components of petroleum is performed by different
hydrocarbon-degrading bacteria, plantsā ability of phytoremediating
different components might therefore vary during the plant life cycle.
Phytoremediation might be most effective during the vegetative growth stages as
greater abundances of hydrocarbon-degrading bacteria containing
alkB and tol genes were observed at these
stages. The information provided by this study enhances our understanding of the
effects of petroleum pollution on plant-microbe interactions and the roles of
these interactions in the phytoremediation of petroleum-polluted soil
HIV-1 drug resistance mutations emerging on darunavir therapy in PI-naive and -experienced patients in the UK
\ua9 The Author 2016. Background: Darunavir is considered to have a high genetic barrier to resistance. Most darunavir-associated drug resistance mutations (DRMs) have been identified through correlation of baseline genotype with virological response in clinical trials. However, there is little information on DRMs that are directly selected by darunavir in clinical settings. Objectives: We examined darunavir DRMs emerging in clinical practice in the UK. Patients and methods: Baseline and post-exposure protease genotypes were compared for individuals in the UK Collaborative HIV Cohort Study who had received darunavir; analyses were stratified for PI history. A selection analysis was used to compare the evolution of subtype B proteases in darunavir recipients and matched PInaive controls. Results: Of 6918 people who had received darunavir, 386 had resistance tests pre- and post-exposure. Overall, 2.8% (11/386) of these participants developed emergent darunavir DRMs. The prevalence of baseline DRMs was 1.0% (2/198) among PI-naive participants and 13.8% (26/188) among PI-experienced participants. Emergent DRMs developed in 2.0% of the PI-naive group (4 mutations) and 3.7% of the PI-experienced group (12 mutations). Codon 77 was positively selected in the PI-naive darunavir cases, but not in the control group. Conclusions: Our findings suggest that although emergent darunavir resistance is rare, it may be more common among PI-experienced patients than those who are PI-naive. Further investigation is required to explore whether codon 77 is a novel site involved in darunavir susceptibility
Assessing Arboreal Adaptations of Bird Antecedents: Testing the Ecological Setting of the Origin of the Avian Flight Stroke
The origin of avian flight is a classic macroevolutionary transition with research spanning over a century. Two competing models explaining this locomotory transition have been discussed for decades: ground up versus trees down. Although it is impossible to directly test either of these theories, it is possible to test one of the requirements for the trees-down model, that of an arboreal paravian. We test for arboreality in non-avian theropods and early birds with comparisons to extant avian, mammalian, and reptilian scansors and climbers using a comprehensive set of morphological characters. Non-avian theropods, including the small, feathered deinonychosaurs, and Archaeopteryx, consistently and significantly cluster with fully terrestrial extant mammals and ground-based birds, such as ratites. Basal birds, more advanced than Archaeopteryx, cluster with extant perching ground-foraging birds. Evolutionary trends immediately prior to the origin of birds indicate skeletal adaptations opposite that expected for arboreal climbers. Results reject an arboreal capacity for the avian stem lineage, thus lending no support for the trees-down model. Support for a fully terrestrial ecology and origin of the avian flight stroke has broad implications for the origin of powered flight for this clade. A terrestrial origin for the avian flight stroke challenges the need for an intermediate gliding phase, presents the best resolved series of the evolution of vertebrate powered flight, and may differ fundamentally from the origin of bat and pterosaur flight, whose antecedents have been postulated to have been arboreal and gliding
Modelling of the effect of ELMs on fuel retention at the bulk W divertor of JET
Effect of ELMs on fuel retention at the bulk W target of JET ITER-Like Wall was studied with multi-scale calculations. Plasma input parameters were taken from ELMy H-mode plasma experiment. The energetic intra-ELM fuel particles get implanted and create near-surface defects up to depths of few tens of nm, which act as the main fuel trapping sites during ELMs. Clustering of implantation-induced vacancies were found to take place. The incoming flux of inter-ELM plasma particles increases the different filling levels of trapped fuel in defects. The temperature increase of the W target during the pulse increases the fuel detrapping rate. The inter-ELM fuel particle flux refills the partially emptied trapping sites and fills new sites. This leads to a competing effect on the retention and release rates of the implanted particles. At high temperatures the main retention appeared in larger vacancy clusters due to increased clustering rate
Virological failure and development of new resistance mutations according to CD4 count at combination antiretroviral therapy initiation
Objectives: No randomized controlled trials have yet reported an individual patient benefit of initiating combination antiretroviral therapy (cART) at CD4 counts > 350 cells/Ī¼L. It is hypothesized that earlier initiation of cART in asymptomatic and otherwise healthy individuals may lead to poorer adherence and subsequently higher rates of resistance development. Methods: In a large cohort of HIV-positive individuals, we investigated the emergence of new resistance mutations upon virological treatment failure according to the CD4 count at the initiation of cART. Results: Of 7918 included individuals, 6514 (82.3%), 996 (12.6%) and 408 (5.2%) started cART with a CD4 count ā¤ 350, 351-499 and ā„ 500 cells/Ī¼L, respectively. Virological rebound occurred while on cART in 488 (7.5%), 46 (4.6%) and 30 (7.4%) with a baseline CD4 count ā¤ 350, 351-499 and ā„ 500 cells/Ī¼L, respectively. Only four (13.0%) individuals with a baseline CD4 count > 350 cells/Ī¼L in receipt of a resistance test at viral load rebound were found to have developed new resistance mutations. This compared to 107 (41.2%) of those with virological failure who had initiated cART with a CD4 count < 350 cells/Ī¼L. Conclusions: We found no evidence of increased rates of resistance development when cART was initiated at CD4 counts above 350 cells/Ī¼L. HIV Medicin
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