Pain catastrophizing, depression, and anxiety in THA patients with differing radiographic severity

Background: Comorbid mood disorders and pain catastrophizing behavior in patients with hip osteoarthritis have been associated with worse pain scores and more functional limitations before and after undergoing a total hip arthroplasty (THA). There remain questions regarding the relationship between severity of hip disease and mental health factors on preoperative measures in patients with differing radiographic disease. The purpose of this study was to assess preoperative pain catastrophizing, depression, and anxiety scores in THA patients with less severe radiographic hip arthritis compared to those with more severe radiographic disease. Methods: A total of 785 patients were enrolled in a prospective cohort of THA patients at a tertiary hip program over a 5-year period. Study participation consisted of preoperative and postoperative survey completion with a minimum of 1-year postoperative follow-up. The Pain Catastrophizing Scale (PCS) was used to assess for pain catastrophizing. The Hospital Anxiety and Depression Scale (HADS-A, HADS-D) was used to assess for anxiety and depression. Radiographic severity was assessed using preoperative radiographs and was graded with the Tönnis classification of osteoarthritis and joint space width. Results: Preoperative and postoperative surveys were completed for 411 patients. Preoperatively, 58 patients (14.11%) had a clinically relevant PCS score, 72 patients (17.52%) had an abnormal HADS-D score, and 69 patients (16.79%) had an abnormal HADS-A score. Tönnis Grade 0/1 patients had more abnormal preoperative HADS-A scores than Tönnis Grade 2/3 patients (20.51% vs 11.11%, p = 0.036). There were no statistically significant differences in the preoperative PCS (p = 0.104) and HADS-D (p = 0.188) scores between Tönnis Grade 0/1 patients and Tönnis Grade 2/3 patients. Conclusions: Our study demonstrates that patients with less severe radiographic disease had greater anxiety scores. This suggests that patients with clinically relevant anxiety were more likely to undergo a THA earlier in the course of their hip pathology rather than continuing with conservative management until they progress to end-stage disease. There was no difference in pain catastrophizing and depression scores between groups of less and more severe hip disease

Disease-specific molecular events in cortical multiple sclerosis lesions

Cortical lesions constitute an important part of multiple sclerosis pathology. Although inflammation appears to play a role in their formation, the mechanisms leading to demyelination and neurodegeneration are poorly understood. We aimed to identify some of these mechanisms by combining gene expression studies with neuropathological analysis. In our study, we showed that the combination of inflammation, plaque-like primary demyelination and neurodegeneration in the cortex is specific for multiple sclerosis and is not seen in other chronic inflammatory diseases mediated by CD8-positive T cells (Rasmussen’s encephalitis), B cells (B cell lymphoma) or complex chronic inflammation (tuberculous meningitis, luetic meningitis or chronic purulent meningitis). In addition, we performed genome-wide microarray analysis comparing micro-dissected active cortical multiple sclerosis lesions with those of tuberculous meningitis (inflammatory control), Alzheimer’s disease (neurodegenerative control) and with cortices of age-matched controls. More than 80% of the identified multiple sclerosis-specific genes were related to T cell-mediated inflammation, microglia activation, oxidative injury, DNA damage and repair, remyelination and regenerative processes. Finally, we confirmed by immunohistochemistry that oxidative damage in cortical multiple sclerosis lesions is associated with oligodendrocyte and neuronal injury, the latter also affecting axons and dendrites. Our study provides new insights into the complex mechanisms of neurodegeneration and regeneration in the cortex of patients with multiple sclerosis

Sending Mixed Signals: A Study of the Melanocortin-1-Receptor

Skin tone varies considerably among humans across the world. These variations are due in part to different types of skin pigments known as melanin. The two main types of melanin are eumelanin and pheomelanin. Eumelanin, a brown/black pigment, is produced in response to ultraviolet radiation (UVR) and provides protection from harmful UV rays. On the other hand, pheomelanin is a red/yellow pigment and is not photoprotective. According to the World Health Organization, skin cancer is one of the most common forms of cancer. Individuals who produce predominantly pheomelanin typically have fair skin, red or blonde hair, are unable to tan, and are at greater risk for developing melanoma skin cancer. Melanoma is cancer of the pigment-producing cells known as melanocytes. UV exposure causes release of the melanocyte stimulating hormone (MSH), which activates a receptor on melanocytes called the melanocortin-1 receptor (MC1R). MSH stimulates MC1R signaling pathways which produce photoprotective eumelanin. In contrast, pheomelanin is produced when the MC1R signaling pathway is inactive. MC1R signaling is typically inactive in individuals who carry melanoma-associated MC1R variants. Two of the most frequent melanoma-associated mutations are MC1R-R151C and MC1R-D294H. Both of these mutations cause red hair, fair skin, and increased skin cancer risk. These mutations also impact surface levels of MC1R, which in turn affect the eumelanin synthesis pathway. Previous work in human embryonic kidney cells suggests that MC1R signaling is reduced in both of these mutations and that MC1R-R151C decreases MC1R surface levels, while MC1R-D294H increases MC1R surface levels. How these mutations alter MC1R localization in melanocytes is unknown. We investigated how MC1R surface levels differ among wild type MC1R and MC1R skin cancer mutants. We observed that MC1R-R151C decreases receptor surface levels and MC1R-D294H increases surface levels in mouse melanocytes

Beck et al. Oikos 2018 Top-Down Bottom-Up Biomass Responses

This file includes data on periphyton biomass response variables including chlorophyll a, ash-free dry mass, and the autotrophic index

Data from: Seasonal shifts in the importance of bottom-up and top-down factors on stream periphyton community structure

We examined the importance of temporal variability in top-down and bottom-up effects on the accumulation of stream periphyton, which are complex associations of autotrophic and heterotrophic microorganisms. Periphyton contributes to primary production and nutrient cycling and serves as a food resource for herbivores (grazers). Periphyton growth is often limited by the availability of nitrogen and phosphorus, and biomass can be controlled by grazers. In this study we experimentally manipulated nutrients and grazers simultaneously to determine the relative contribution of bottom-up and top-down controls on periphyton over time. We used nutrient diffusing substrates to regulate nutrient concentrations and an underwater electric field to exclude grazing insects in three sequential 16-17 day experiments from August to October in montane Colorado, USA. We measured algal biomass, periphyton organic mass, and algal community composition in each experiment and determined densities of streambed insect species, including grazers. Phosphorus was the primary limiting nutrient for algal biomass, but it did not influence periphyton organic mass across all experiments. Effects of nutrient additions on algal biomass and community composition decreased between August and October. Grazed substrates supported reduced periphyton biomass only in the first experiment, corresponding to high benthic abundances of a dominant mayfly grazer (Rhithrogena spp.). Grazed substrates in the first experiment also showed altered algal community composition with reduced diatom relative abundances, presumably in response to selective grazing. We showed that top-down grazing effects were strongest in late summer when grazers were abundant. The effects of phosphorus additions on algal biomass likely decreased over time because temperature became more limiting to growth than nutrients, and because reduced current velocity decreased nutrient uptake rates. These results suggest that investigators should proceed with caution when extending findings based on short-term experiments. Furthermore, these results support the need for additional seasonal-scale field research in stream ecology

Beck et al. Oikos 2018 Top-Down Bottom-Up Community Responses

This file includes data on the community composition response variables (green algae, cyanobacteria, and diatoms) determined using UPLC-UV-MS pigment analysis

The role of warm, dry summers and variation in snowpack on phytoplankton dynamics in mountain lakes

Climate change is altering biogeochemical, metabolic, and ecological functions in lakes across the globe. Historically, mountain lakes in temperate regions have been unproductive because of brief ice-free seasons, a snowmelt-driven hydrograph, cold temperatures, and steep topography with low vegetation and soil cover. We tested the relative importance of winter and summer weather, watershed characteristics, and water chemistry as drivers of phytoplankton dynamics. Using boosted regression tree models for 28 mountain lakes in Colorado, we examined regional, intraseasonal, and interannual drivers of variability in chlorophyll a as a proxy for lake phytoplankton. Phytoplankton biomass was inversely related to the maximum snow water equivalent (SWE) of the previous winter, as others have found. However, even in years with average SWE, summer precipitation extremes and warming enhanced phytoplankton biomass. Peak seasonal phytoplankton biomass coincided with the warmest water temperatures and lowest nitrogen-to-phosphorus ratios. Although links between snowpack, lake temperature, nutrients, and organic-matter dynamics are increasingly recognized as critical drivers of change in high-elevation lakes, our results highlight the additional influence of summer conditions on lake productivity in response to ongoing changes in climate. Continued changes in the timing, type, and magnitude of precipitation in combination with other globalchange drivers (e.g., nutrient deposition) will affect production in mountain lakes, potentially shifting these historically oligotrophic lakes toward new ecosystem states. Ultimately, a deeper understanding of these drivers and pattern at multiple scales will allow us to anticipate ecological consequences of global change better