Myosin VI-Dependent Actin Cages Encapsulate Parkin-Positive Damaged Mitochondria

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Polyhedrocytes in blood clots of type 2 diabetic patients with high cardiovascular risk: association with glycemia,oxidative stress and platelet activation

Background

Little is known about factors that affect the composition of contracted blood clots in specific diseases. We investigated the content of polyhedral erythrocytes (polyhedrocytes) formed in blood clots and its determinants in type 2 diabetes (T2D) patients.

Methods

In 97 patients with long-standing T2D [median HbA_1c, 6.4% (interquartile range 5.9–7.8)], we measured in vitro the composition of blood clots, including a clot area covered by polyhedrocytes using scanning electron microscopy and the erythrocyte compression index (ECI), defined as a ratio of the mean polyhedrocyte area to the mean native erythrocyte area. Moreover, plasma fibrin clot permeability (K_s), clot lysis time (CLT), thrombin generation, oxidative stress [total protein carbonyl (total PC), total antioxidant capacity and thiobarbituric acid reactive substances (TBARS)], and platelet activation markers were determined. The impact of glucose concentration on polyhedrocytes formation was assessed in vitro.

Results

Polyhedrocytes content in contracted clots was positively correlated with glucose (r?=?0.24, p?=?0.028), glycated hemoglobin (r?=?0.40, p?=?0.024), total cholesterol (r?=?0.22, p?=?0.044), TBARS (r?=?0.60, p?=?0.0027), P-selectin (r?=?0.54, p?=?0.0078) and platelet factor-4, PF4 (r?=?0.59, p?=?0.0032), but not with thrombin generation, platelet count, K_s or CLT. Patients who formed more polyhedrocytes (≥?10th percentile) (n?=?83, 85.6%) had higher glucose (+?15.7%, p?=?0.018), fibrinogen (+?16.6%, p?=?0.004), lower red blood cell distribution width (RDW, ??8.8%, p?=?0.034), reduced plasma clot density (??21.8% K_s, p?=?0.011) and impaired fibrinolysis (+?6.5% CLT, p?=?0.037) when compared to patients with lesser amount of polyhedrocytes (<?10th percentile). ECI and the content of polyhedrocytes were strongly associated with total PC (r?=?0.79, p?=?0.036 and r?=?0.67, p?=?0.0004, respectively). In vitro an increase of glucose concentration by 10 mmol/L was associated with 94% higher polyhedrocytes content (p?=?0.033) when compared to the baseline (7.1 mM). After adjustment for age, sex and fibrinogen, multiple regression analysis showed that RDW was the only independent predictor of polyhedrocytes content in T2D (OR?=?0.61, 95% CI 0.39–0.92).

Conclusions

Poor glycemic control, together with enhanced platelet activation and oxidative stress, increase the content of polyhedrocytes in blood clots generated in T2D patients.

     

Investigating Niche Construction in Dynamic Human-Animal Landscapes: Bridging Ecological and Evolutionary Timescales

Human influence on the environment is evident at all landscape and ecological scales, from local to global, shaping both abiotic and biotic processes. Niche construction theory provides a means by which to investigate the consequences of these anthropogenic effects, but primatological research has been slow to integrate ecological and evolutionary timelines. We review methods that can be used to study how human niche construction influences nonhuman primates including phenological assessment, nonhuman primate behavioral observations, and ethnographic interview techniques. We argue that this approach provides a starting place to examine niche construction theory but that scholars of primate behavioral ecology must expand our methodologies to bridge the disconnect between ecological and evolutionary research time frames. We suggest areas of research and methods that have been underused but offer opportunities for integrative, innovative research. We conclude that an integrated, synthetic methodological approach is a major goal and that it will likely require a cross-disciplinary, collaborative effort.     

PATTERNS OF RELATIVE GROWTH IN NEREOCYSTIS LUETKEANA (PHAEOPHYTA)1

Plants of Nereocystis luetkeana (Mert.) Post. et Rupr. of different sizes were held on a raft at the surface of the sea off the Friday Harbor Laboratories, San Juan Island, Washington for 5 day periods for observation of detailed relative growth of different parts. Each stipe was marked at intervals with injected Indian ink and each blade was punched with a series of holes. Measurements of diameter, length, width and thickness were made before and after the 5 day periods. Blades showed a very similar pattern of relative growth rate (R) over an 18-fold range of sizes. The maximum local R in length was about 0.2 day⁻¹ and occurred at 6.5% of the distance from the bulb to the tip, declining to 0.01 at half way. Half the linear growth occurred in the proximal one tenth of the blade and 95% within the proximal half. The relative growth rate of the whole blade declined only slightly with increased size and lay between 0.0.3 and 0.06 day⁻¹ (approx. 3–6% day⁻¹). The linear growth rate therefore increased with blade size, the maximum observed being 14 cm day⁻¹. The maximum relative growth rate in blade width was slower, and sited more distally than that in length. Unless fertile tissue was involved all blade tissue, except that closely adjoining the bulb, became thinner during growth. R in volume reached 0.3 day⁻¹. Presumably because the plants were held near the sea surface stipes grew slowly, with a maximum linear rate of 9 mm day⁻¹. The maximum R in length decreased with stipe length. Bulb R in volume also decreased as size increased, from a maximum of 0.3 day⁻¹.     

Responses of crustose corallines to epiphyte and canopy cover

Although a dense cover of epiphytes is generally considered to be harmful for some coralline algae (Corallinaceae, Rhodophyta), crustose corallines in the littoral zone seem to be preserved from bleaching when covered by canopy plants and epiphytes during summer. This study aimed to test the responses of coralline crusts to epiphytes and canopy algae and their interaction with grazing limpets. Growth rates and color changes were followed in two crust species in areas with or without canopy algae in the Isle of Man, British Isles. Limpets were excluded, to allow epiphytes to grow upon crusts. Responses were measured both on pieces of crusts upon acrylic plates and on crusts growing naturally on the shore. Fucus canopy and epiphytic Enteromorpha significantly influenced the crusts' growth, depending on season. Epiphytes reduced the light levels beneath by up to 78%, more than the canopy algae (62%). Crusts exposed outside the canopy bleached in summer, but gradually restored their color once they were covered by epiphytes. The fast-growing Phymatolithon lenormandii (Aresch.) Adey recovered its coloration more quickly than the slow-growing P. purpureum (P. et H. Crouan) Woelkerling et Irvine. However, neither crust species could restore its color when epiphytes were reduced by grazing limpets, Patella vulgata L. Bleaching did not kill the crusts, but seemed to interfere with crusts' growth. Restoration of pigmentation was quantified for the first time on bleached coralline crusts. Epiphyte and canopy algae were experimentally shown to be beneficial, probably by providing shade and also protecting crusts from desiccation.     

Male-biased sex ratio among unhatched eggs in great tit Parus major, blue tit P. caeruleus and collared flycatcher Ficedula albicollis

An increasing number of studies have demonstrated that brood sex ratios are frequently unequal, but the proximate mechanisms underlying this deviation are largely unknown. In the current study we analysed deviation from expected 1:1 sex ratio among dead embryos from unhatched eggs collected from partially unhatched clutches of three passerine bird species. We showed that male embryos were significantly overrepresented among unhatched eggs of great tit Parus major , blue tit P. caeruleus and collared flycatcher Ficedula albicollis . Moreover, the bias in sex ratio differed among species and tended to differ among study years. We discuss several hypotheses to explain the observed male bias among unhatched eggs. We conclude that sex specific embryo mortality may contribute to explain the observed variation in sex ratios in several species of wild birds and that sexing unhatched eggs is important in studies of sex ratio allocation.     

Suppression of contact hypersensitivity after repeated exposures of humans to low doses of solar simulated radiation.

Although it is generally recognised that UV radiation (UVR) can induce suppression of contact hypersensitivity (CHS) in human subjects, most protocols to date have not tested the effect of low daily doses of solar simulated radiation (SSR). In the present study, healthy individuals, divided into four groups each consisting of approximately 34 subjects, were whole-body irradiated with 1.2 standard erythema doses of SSR for 2, 10 or 30 consecutive days, or were unirradiated. They were sensitised with diphenylocyclopropenone (DPCP) on one exposed body site 24 h after the final UVR. The occurrence and severity of the primary allergic response were noted, and both parameters were shown to be significantly lowered in the group irradiated for 30 days compared with the unirradiated group. Elicitation of CHS was undertaken 3 weeks after the sensitisation, using a range of concentrations of DPCP on a UV-protected body site. The extent of the CHS at 48 h was assessed by the clinical score, by an erythema meter and by histological examination of a biopsy taken from the site challenged with one selected concentration of DPCP. Although erythema and pigmentation did not differ between the groups, a significant negative correlation was found between the clinical CHS score and the number of days of UV exposure, at the lowest challenge dose of DPCP. In addition a significant negative correlation was revealed between the intensity of spongiosis (intraepidermal oedema and vesicles, as evaluated by histology) and the number of days of UV exposure. Thus small daily doses of SSR induce suppression of CHS in human subjects and the effect is cumulative, indicating that there is no adaptation to the immunomodulating effects of UVR, at least over the test period of 30 days.