Evolutionary psychology of spatial representations in the hominidae

Comparatively little is known about the inherited primate background underlying human cognition, the human cognitive "wild-type." Yet it is possible to trace the evolution of human cognitive abilities and tendencies by contrasting the skills of our nearest cousins, not just chimpanzees, but all the extant great apes, thus showing what we are likely to have inherited from the common ancestor. By looking at human infants early in cognitive development, we can also obtain insights into native cognitive biases in our species. Here, we focus on spatial memory, a central cognitive domain. We show, first, that all nonhuman great apes and 1-year-old human infants exhibit a preference for place over feature strategies for spatial memory. This suggests the common ancestor of all great apes had the same preference. We then examine 3-year-old human children and find that this preference reverses. Thus, the continuity between our species and the other great apes is masked early in human ontogeny. These findings, based on both phylogenetic and ontogenetic contrasts, open up the prospect of a systematic evolutionary psychology resting upon the cladistics of cognitive preferences.     

Community regulation by herbivore parasitism and density: Trait-mediated indirect interactions in the intertidal

The abundant herbivorous mud-snail Hydrobia ulvae is an ecosystem engineer in soft-bottom intertidal habitats due to its grazing and bioturbation activity. However, mud snails are commonly infected by trematodes that reduce their overall activity, which in turn may affect their impact on the surrounding benthic community. To test this hypothesis, we performed field experiments manipulating both the abundance of uninfected snails (0, 7500 and 15.000 ind. m^- 2) and the level of snail parasitism (0, 33 and 100% trematode prevalence) on a Danish mud-flat. The results showed that increasing snail abundance and parasitism generally had opposite effects on the community of microphytobenthos and zoobenthos. Increasing snail density increased the chlorophyll-a concentration in the substrate (enhancement), whereas increasing parasitism decreased it. In accordance, the benthic primary producers were generally less nutrient limited at high snail density and mostly so at high levels of snail parasitism. Moreover, epipsammic diatoms were favoured over epipelic diatoms at increasing snail density, whereas the opposite was evident at increasing snail parasitism. At the community level, increasing snail density increased evenness among epipelic diatoms, whereas increasing snail parasitism decreased evenness and species diversity. Probably through the action of trophic cascades and varying levels of disturbance, the zoobenthic community was influenced by experimental treatments as well. The indirect effects of snail parasitism influenced significantly the abundance of more faunal species (seven) than did snail density (two). At the community level, increasing snail density decreased evenness and lowest species richness coincided with intermediate snail density. In contrast, increasing snail parasitism resulted in increasing evenness and peaking species richness at intermediate level of parasitism. Together, the results show that parasites solely through their impact on the behaviour of a single community member can be significant indirect determinants of community organisation and function.     

Development of models for specific crop calendar events

In order to test growth prediction and yield prediction equations on historical weather data for areas where planting dates were not published, or for areas where dates of planting will not be as readily accessible as weather data, there is a need for a model to predict the date of planting. Such a model was developed by regressing reported percentages of the wheat crop planted on various weather variables and their transformations. The model for predicting percentage of wheat acreage planted in North Dakota was tested on data not used in formulating the coefficients of the model. Although the predictions may have errors of several days the model is considered to be an improvement over a system utilizing a constant year-to-year average planting date.The research was supported by funds supplied by the National Aeronautics and Space Administration under contract No. NAS 9-14006.Presented at the Seventh International Biometeorological Congress, 17–23 August 1975, College Park, Maryland, USA.     

A simple method for studying whole sections of rice grain

We developed a new and simple method to collect sections of a whole brown rice kernel for investigation of histological properties. A single kernel of rice was dehydrated through a graded ethanol series, transferred to xylene, and embedded in paraffin. During sectioning of the blocks using a rotary microtome, we used a special adhesive tape to collect and place the sections on slides so they remained flat. The use of the adhesive tape technique combined with autofluorescence characteristics allowed us to visualize cell walls throughout an entire longitudinal or transverse section of a whole rice kernel. We obtained scanning electron microscopy images of the sections to determine section quality.     

Health-related quality of life and functional ability in patients with early arthritis during remission steered treatment: results of the IMPROVED study

Introduction

The aim of this study was to investigate patient reported outcomes (PROs) of functional ability and health related quality of life (HRQoL) in patients with early (rheumatoid) arthritis during one year of remission steered treatment.

Methods

In this study, 610 patients with early rheumatoid arthritis (RA) or undifferentiated arthritis (UA) were treated with methotrexate (MTX) and tapered high dose of prednisone. Patients in early remission (Disease Activity Score (DAS) <1.6 after 4 months) tapered prednisone to zero and when in persistent remission, also tapered MTX. Patients not in early remission were randomized to either MTX + hydroxychloroquine + sulphasalazine + prednisone (arm 1) or to MTX + adalimumab (arm 2). Every 4 months, patients filled out the Health Assessment Questionnaire (HAQ) and the McMaster Toronto Arthritis Patient Preference Questionnaire (MACTAR), the Short Form 36 (SF-36) and visual analogue scales (VAS). Change scores were compared between treatment groups. The association with achieving remission was analyzed using linear mixed models.

Results

During year 1, patients who achieved early remission had the most improvement in PROs with scores comparable to the general population. Patients in the randomization arms showed less improvement. Scores were comparable between the arms. There was a significant association between achieving remission and scores of HAQ, MACTAR and physical HRQoL.

Conclusions

In early arthritis, PROs of functional ability and HRQoL after one year of remission steered treatment reach normal values in patients who achieved early remission. In patients not in early remission, who were randomized to two strategy arms, PROs improved less, with similar scores in both treatment arms.

Trial registrations

ISRCTN11916566 and EudraCT2006-006186-16     

Synovial T cell hyporesponsiveness to myeloid dendritic cells is reversed by preventing PD-1/PD-L1 interactions

Introduction

The aim of this study was to investigate PD-1/PD-L1 involvement in the hyporesponsiveness of rheumatoid arthritis (RA) synovial fluid (SF) CD4 T cells upon stimulation by thymic stromal lymphopoietin (TSLP)–primed CD1c myeloid dendritic cells (mDCs).

Methods

Expression of PD-1 on naïve (Tn), central memory (Tcm) and effector memory (Tem) CD4 T cell subsets was assessed by flow cytometry. PD-L1 expression and its regulation upon TSLP stimulation of mDCs from peripheral blood (PB) and SF of RA patients were investigated by quantitative RT-PCR and flow cytometry. The involvement of PD-1/PD-L1 interactions in SF T cell hyporesponsiveness upon (TSLP-primed) mDC activation was determined by cell culture in the presence of PD-1 blocking antibodies, with or without interleukin 7 (IL-7) as a recognized suppressor of PD-1 expression.

Results

PD-1 expression was increased on CD4 T cells derived from SF compared with PB of RA patients. TSLP increased PD-L1 mRNA expression in both PB and SF mDCs. PD-L1 protein expression was increased on SF mDCs compared with PB mDCs and was associated with T cell hyporesponsiveness. Blockade of PD-1, as well as IL-7 stimulation, during cocultures of memory T cells and (TSLP-primed) mDCs from RA patients significantly recovered T cell proliferation.

Conclusion

SF T cell hyporesponsiveness upon (TSLP-primed) mDC stimulation in RA joints is partially dependent on PD-1/PD-L1 interactions, as PD-1 and PD-L1 are both highly expressed on SF T cells and mDCs, respectively, and inhibiting PD-1 availability restores T cell proliferation. The potential of IL-7 to robustly reverse this hyporesponsiveness suggests that such proinflammatory cytokines in RA joints strongly contribute to memory T cell activation.     

A musculo-skeletal model of rat ankle motion and its experimental test on rat

A biomechanical musculo-skeletal model of functional electrical stimulation (FES)-induced rat ankle motion was implemented and tested in rat experiments. The muscle model is a new Hill-based model which includes established physiological relations of force-velocity and force-length-frequency. However, the series-elastic component and the activation component of previous Hill-based models are replaced by a new component which accounts for dynamic time delays and recruitment that occur in real muscle force generation during limb movements. The skeletal model includes gravity and dynamic forces that occur in real rat ankle motions. In computer simulations, various FES patterns were applied to the tibialis anterior (TA) and soleus (SO) model muscles to produce walk-like ankle motions. In lab experiments, the same stimulation patterns were applied by epimysial electrodes implanted in the TA and SO muscles of live rats cordotomized at level T7. The resulting rat motions were recorded by video camera. Video data was converted to ankle angle-vs-time files for comparison with corresponding model angle-vs-time files. Over a physiologically significant range of ankle motions, model parameters were adjustable to yield model motions that agreed with rat motions to within 2 degrees (root mean square differences of rat and model ankle angles). This is shown in plots of model and rat motions presented here for representative cases of FES. The accuracy of our model in reproducing real ankle motions supports the hypothesis that our new muscle model generates correct muscle forces over a useful range of limb motions. It suggests that the model may be useful in the design of FES neural prostheses.     

Seasonal occurrence and ecological aspects of Afrodiplozoon polycotyleus (Monogenea: Diplozoidae) from the gills of three cyprinids from the Nwanedi-Luphephe dams,South Africa

The effect of seasonal changes and ecological aspects of Afrodiplozoon polycotyleus (Paperna, 1973) collected on Labeobarbus marequensis (Smith, 1841), Enteromius trimaculatus (Peters, 1852) and Enteromius radiatus (Peters, 1853) was investigated from January to October 2008. Fish were collected at the Nwanedi-Luphephe dams, Limpopo River System, South Africa using gill, cast and seine nets and electrofishing gear. Enteromius radiatus and E. trimaculatus were the most infested compared with L. marequensis. Seasonal changes had an influence on the intensity of A. polycotyleus, with infestation rates higher in spring, summer and autumn. The adults predominantly infected the medial region of the second gill arch, whereas diporpae were mainly found on the first gill. Neither sex nor water quality changes had an influence on the intensity of the parasite. The health condition of the hosts was not affected by the parasite. The different infestation rates of the parasite between the species could be attributed to host characteristics, behaviour and habitat preferences. The selection of a particular gill/region could be attributed to space for attachment organs and food supply, as well as flow and velocity of the water over the gills. The occurrence of A. polycotyleus on E. radiatus constitutes a new host record.     

Studies on ageing and the severity of radiographic joint damage in rheumatoid arthritis

IntroductionThe western population is ageing. It is unknown whether age at diagnosis affects the severity of Rheumatoid Arthritis (RA), we therefore performed the present study.Method1,875 RA-patients (7,219 radiographs) included in five European and North-American cohorts (Leiden-EAC, Wichita, Umeå, Groningen and Lund) were studied on associations between age at diagnosis and joint damage severity. In 698 Leiden RA-patients with 7-years follow-up it was explored if symptom duration, anti-citrullinated-peptide-antibodies (ACPA), swollen joint count (SJC) and C-reactive-protein (CRP) mediated the association of age with joint damage. Fifty-six other RA-patients of the EAC-cohort underwent baseline MRIs of wrist, MCP and MTP-joints; MRI-inflammation (RAMRIS-synovitis plus bone marrow edema) was also evaluated in mediation analyses. Linear regression and multivariate normal regression models were used.ResultsAnalysis on the five cohorts and the Leiden-EAC separately revealed 1.026-fold and 1.034-fold increase of radiographic joint damage per year increase in age (β=1.026, 1.034, both p<0.001); this effect was present at baseline and persisted over time. Age correlated stronger with baseline erosion-scores compared to joint space narrowing (JSN)-scores (r=0.38 versus 0.29). Symptom duration, ACPA, SJC and CRP did not mediate the association of age with joint damage severity. Age was significantly associated with the MRI-inflammation-score after adjusting for CRP and SJC (β=1.018, p=0.027). The association of age with joint damage (β=1.032, p=0.004) decreased after also including the MRI-inflammation-score (β=1.025, p=0.021), suggesting partial mediation.ConclusionRA-patients presenting at higher age have more severe joint damage; this might be partially explained by more severe MRI-detected inflammation at higher age.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-015-0740-0) contains supplementary material, which is available to authorized users.