Deletion of EP4 in S100a4-lineage cells reduces scar tissue formation during early but not later stages of tendon healing

AbstractTendon injuries heal via scar tissue rather than regeneration. This healing response forms adhesions between the flexor tendons in the hand and surrounding tissues, resulting in impaired range of motion and hand function. Mechanistically, inflammation has been strongly linked to adhesion formation, and Prostaglandin E2 (PGE2) is associated with both adhesion formation and tendinopathy. In the present study we tested the hypothesis that deletion of the PGE2 receptor EP4 in S100a4-lineage cells would decrease adhesion formation. S100a4-Cre; EP4flox/flox (EP4cKOS100a4) repairs healed with improved gliding function at day 14, followed by impaired gliding at day 28, relative to wild type. Interestingly, EP4cKOS100a4 resulted in only transient deletion of EP4, suggesting up-regulation of EP4 in an alternative cell population in these mice. Loss of EP4 in Scleraxis-lineage cells did not alter gliding function, suggesting that Scx-lineage cells are not the predominant EP4 expressing population. In contrast, a dramatic increase in α-SMA+, EP4+ double-positive cells were observed in EP4cKOS100a4 suggesting that EP4cKOS100a4 repairs heal with increased infiltration of EP4 expressing α-SMA myofibroblasts, identifying a potential mechanism of late up-regulation of EP4 and impaired gliding function in EP4cKOS100a4 tendon repairs.</jats:p

Predictive validity of the UK clinical aptitude test in the final years of medical school:a prospective cohort study

Peer reviewedPublisher PD

Interactive Effects of Drought and Fire on Co-Existing Woody and Herbaceous Communities in a Temperate Mesic Grassland

Increased drought and woody encroachment are likely to have substantial and interactive effects on grassland carbon and water cycling in the future. However, we currently lack necessary information to accurately predict grassland responses to drought-by-fire interactions in areas experiencing woody encroachment. A more thorough understanding of these interactive effects on grass-shrub physiology would improve the effectiveness of demographic vegetation models and refine predictions of future changes in grassland ecosystem function. To this end, we constructed passive rainout shelters over mature Cornus drummondii shrubs and co-existing grasses in two fire treatments (1-year and 4-year burn frequency) at the Konza Prairie Biological Station (north-eastern Kansas, USA) that reduced precipitation by 50%. Plant responses to drought and fire were monitored at the leaf-level (gas exchange, predawn and midday water potential, turgor loss point) and the whole-plant level (aboveground biomass). Here, we report results from the 2020 growing season, after three years of treatment. Photosynthetic rates of C. drummondii and Andropogon gerardii, a dominant C4 grass, were lower in drought treatments at the end of the growing season. A. gerardii also exhibited higher photosynthetic rates in the 4-year burn watershed, but C. drummondii rates were not impacted by burn frequency. Predawn and midday leaf water potential for both species, as well as turgor loss point for C. drummondii, were lower in the 4-year burn treatment, indicating increased water stress. This trend was more pronounced in drought shelters for C. drummondii. These results indicate that three years of 50% precipitation reduction has resulted in modest impacts on water stress and gas exchange in both species. Long-term studies of co-existing grasses and shrubs are useful for informing management of woody encroachment during drought and help to identify whether multiple external pressures (drought and fire) are needed to reverse grassland-to-shrubland transitions in temperate mesic grasslands

Hydraulic Responses of Shrubs and Grasses to Fire Frequency and Drought in a Tallgrass Prairie Experiencing Bush Encroachment

The increase in abundance and density of woody plants in herbaceous ecosystems (i.e. bush encroachment) is occurring globally and is driven by reduced fire frequency, climate change, and the utilization of deeper, more reliable soil water by woody plants. Thus, a comprehensive understanding of the physiological processes through which woody and herbaceous plants use water will provide greater insight into the mechanisms of bush encroachment, as well as the trajectory of encroachment in a changing climate. Our objective was to assess how experimental changes in water availability and fire frequency impact belowground water-use traits in Cornus drummondii, the primary encroaching shrub within North American tallgrass prairies, and Andropogon gerardii, a dominant C4 grass. Shelters that reduced precipitation by 50% (drought) and 0% (control) were built over mature shrubs growing in sites that were burned at 1-year and 4-year frequencies. We assessed the water transport capability of shrubs and grasses growing in each treatment by measuring the maximum hydraulic conductance (Kmax) of entire root systems. We also assessed the vulnerability of shrub root segments to loss of hydraulic function by measuring the pressure at which 50% of the maximum hydraulic conductivity is lost (P50). Grass and shrub roots had opposite responses to drought and these patterns varied with fire treatment. Grasses growing in drought plots had lower root Kmax than control grasses. Conversely, root Kmax did not differ significantly between treatments in shrubs. However, drought shrub roots were less vulnerable to water stress than control roots (P50=-1.5 and -0.20 MPa, respectively). These results suggest that the ability of grass roots to use water declined with drought, while the ability of shrub roots to resist water stress increased with drought. Future work should investigate whether these drought responses are associated with altered root growth patterns

The vertebrate fauna of the Upper Permian of Niger—III, morphology and ontogeny of the hindlimb of Moradisaurus grandis (Reptilia, Captorhinidae)

We describe hindlimb elements of the large captorhinid Moradisaurus grandis (Reptilia: Captorhinidae) recently collected from the Upper Permian Moradi Formation of north-central Niger. This description is based primarily on an associated partial skeleton comprising a hemimandible, vertebral column, and partial left and nearly complete right hindlimb. Additionally, we report on a well-preserved, articulated, and essentially complete juvenile pes that provides important information on the ontogeny of the captorhinid tarsus. The hindlimb of Moradisaurus is stout and more massively built than in any other known captorhinid. The femur displays several features interpreted as adaptations to the demands of large body size, and the tibia and fibula have short, wide shafts and hypertrophied condyles and epicondyles. The astragalus is very derived, possessing two accessory ossifications and a relatively horizontal tibial articulation, indicating that the tibia was held more vertically than in other captorhinids. The calcaneum is co-ossified with distal tarsal five. The juvenile pes indicates that the captorhinid centrale arose from the fusion of two ossification centers, and that the captorhinid astragalus arose from the fusion of at least three ossification centers

Representational capacity of a set of independent neurons

The capacity with which a system of independent neuron-like units represents a given set of stimuli is studied by calculating the mutual information between the stimuli and the neural responses. Both discrete noiseless and continuous noisy neurons are analyzed. In both cases, the information grows monotonically with the number of neurons considered. Under the assumption that neurons are independent, the mutual information rises linearly from zero, and approaches exponentially its maximum value. We find the dependence of the initial slope on the number of stimuli and on the sparseness of the representation.Comment: 19 pages, 6 figures, Phys. Rev. E, vol 63, 11910 - 11924 (2000

Avian Host-Selection by Culex pipiens in Experimental Trials

Evidence from field studies suggests that Culex pipiens, the primary mosquito vector of West Nile virus (WNV) in the northeastern and north central United States, feeds preferentially on American robins (Turdus migratorius). To determine the contribution of innate preferences to observed preference patterns in the field, we conducted host preference trials with a known number of adult female C. pipiens in outdoor cages comparing the relative attractiveness of American robins with two common sympatric bird species, European starling, Sternus vulgaris and house sparrow, Passer domesticus. Host seeking C. pipiens were three times more likely to enter robin-baited traps when with the alternate host was a European starling (n = 4 trials; OR = 3.06; CI [1.42–6.46]) and almost twice more likely when the alternative was a house sparrow (n = 8 trials; OR = 1.80; CI = [1.22–2.90]). There was no difference in the probability of trap entry when two robins were offered (n = 8 trials). Logistic regression analysis determined that the age, sex and weight of the birds, the date of the trial, starting-time, temperature, humidity, wind-speed and age of the mosquitoes had no effect on the probability of a choosing a robin over an alternate bird. Findings indicate that preferential feeding by C. pipiens mosquitoes on certain avian hosts is likely to be inherent, and we discuss the implications innate host preferences may have on enzootic WNV transmission

Are there socioeconomic inequalities in polypharmacy among older people? A systematic review and meta-analysis

Background: Socioeconomic status (SES) may influence prescribing, concordance and adherence to medication regimens. This review set out to investigate the association between polypharmacy and an individual’s socioeconomic status. Methods: A systematic review and meta-analyses of observational studies was conducted across four databases. Older people (≥ 55 years) from any healthcare setting and residing location were included. The search was conducted across four databases: Medline (OVID), Web of Science, Embase (OVID) and CINAHL. Observational studies from 1990 that reported polypharmacy according to SES were included. A random-effects model was undertaken comparing those with polypharmacy (≥ 5 medication usage) with no polypharmacy. Unadjusted odds ratios (ORs), 95% confidence intervals (CIs) and standard errors (SE) were calculated for each study. Results: Fifty-four articles from 13,412 hits screened met the inclusion criteria. The measure of SES used were education (50 studies), income (18 studies), wealth (6 studies), occupation (4 studies), employment (7 studies), social class (5 studies), SES categories (2 studies) and deprivation (1 study). Thirteen studies were excluded from the meta-analysis. Lower SES was associated with higher polypharmacy usage: individuals of lower educational backgrounds displayed 21% higher odds to be in receipt of polypharmacy when compared to those of higher education backgrounds. Similar findings were shown for occupation, income, social class, and socioeconomic categories. Conclusions: There are socioeconomic inequalities in polypharmacy among older people, with people of lower SES significantly having higher odds of polypharmacy. Future work could examine the reasons for these inequalities and explore the interplay between polypharmacy and multimorbidity

Fun versus Practical: Physiological Responses and Preference of Exercise Equipment

The elliptical cross trainer has become a popular a mode of exercise, but can only be used indoors. The StreetStrider was designed as an outdoor elliptical-bike. PURPOSE: The purpose of this study is to determine whether the elliptical or the StreetStrider was more enjoyable, and to compare the physiological variables for energy expenditure, heart rate (HR), VO2, and Rate of Perceived Exertion (RPE). METHODS: Thirty participants (15 male, 15 female, mean age=22±2) from Cleveland State University exercised for 20 minutes at 75% of their age predicted maximal heart rate on the StreetStrider and elliptical. Energy expenditure was measured with a COSMED K4b metabolic system. Participants’ RPE was recorded every five minutes using the Borg Scale for Rate of Perceived Exertion. Data was analyzed using SPSS version 18. A paired sample t-test compared physiological responses. A one-way ANOVA analyzed gender differences. A significance level of .05 was used to determine significance. RESULTS: No significant differences were shown in energy expenditure (p=.930), HR (p=.098), or in average RPE (p=.529) between the exercise trials. A preference survey concluded that most subjects found the StreetStrider more enjoyable than the elliptical. CONCLUSION: The StreetStrider is more enjoyable than the elliptical and as effective in energy expenditure, and could serve as a substitute for the elliptical.https://engagedscholarship.csuohio.edu/u_poster_2014/1034/thumbnail.jp

Comparison of Electronic and Mechanical Handgrip Devices in Lowering Blood Pressure

Hypertension causes billions of deaths per year (Millar et al., 2013). The Zona PlusTM is an expensive tool designed to lower blood pressure (BP) using isometric exercise. This exercise may be achieved using a less expensive Handgrip Dynamometer. PURPOSE: The purpose of this research is to determine if the Zona or Handgrip Dynamometer is more efficient at lowering BP and most cost effective for patients. METHODS: Twenty subjects used the Zona and twenty subjects used the dynamometer three times per week for six weeks. BP was taken once per week prior to the treatment. A maximum voluntary contraction (MVC) was recorded for each hand before every treatment. Participants were required to hold the handgrip at 30% of their MVC for four two-minute contractions. A paired samples T test was used to analyze changes in participants’ BP. A one-way ANOVA was used to compare the BP changes between the Zona and the Handgrip. RESULTS: The results indicated no significant changes in participants’ pre- and post- treatment after training when using the Zona for either stolic (p=0.225) or diastolic BP (p=1.000). There was also no significant difference in participants’ post treatment systolic BP (p=0.199), however, the post treatment for diastolic increased significantly (p=0.027 BP between those that used the Zona PlusTM and Handgrip Dynamometer. CONCLUSION: Though the Dynamometer is more cost efficient, neither the Zona nor the Dynamometer resulted in lowered BP.https://engagedscholarship.csuohio.edu/u_poster_2014/1037/thumbnail.jp