Micropatterned surfaces for the control of endothelial cell behaviour

Micropatterned materials were synthesised by photoimmobilising the sulphated hyaluronic acid, adequately functionalised with a photoreactive moiety, on glass substrates. Four different patterns (10, 25, 50 and 100 microns) were obtained. The spectroscopic and microscopic analysis of the microstructured surfaces revealed that the photoimmobilisation process was successful, demonstrating that the photomask was well reproduced on the sample surface. Analysis of endothelial cell behaviour on these micropatterned materials was performed in terms of adhesion, locomotion and orientation. Decreasing the stripe dimensions a more fusiform shape of the adhered endothelial cells was observed. At the same time the cell locomotion and orientation were increased. Furthermore, a photoimmobilisation of stripes of HyalS (10 and 100 microns) was performed on a continuous HyalS layer, in turn immobilised on glass substrate. Being excluded a different chemistry between the stripe and the substrate, the influence of topography on the behaviour of endothelia cells was thus envisaged.     

Fibrinogen conformation and platelet reactivity in relation to material-blood interaction: effect of stress hormones

The performance of many biomaterials in hemocompatibility tests is altered when blood is drawn from stressed subjects. A salient physiological response during stress is one in which hormones are released into plasma by the hypothalamo-pituitary-adrenal axis. We investigated the influence of basal and stress levels of epinephrine and beta-endorphin on the conformation of fibrinogen (Fbg), both in saline solution (under physiological conditions) and after its adsorption to polyethylene (PE), by FT-IR spectroscopy. Moreover, as Fbg is one of the major mediators of platelet adhesion, the behavior of platelets in contact with PE was also evaluated as a function of the two different hormone concentrations. Epinephrine was found to affect Fbg conformation and to increase platelet adhesion to PE at stress level. Basal and stress levels of beta-endorphin did not significantly affect the Fbg conformation and only induced adhesion of isolated platelets to the PE surface. A direct relationship was therefore found between Fbg conformation and platelet behavior. The response of platelets was affected by the stress status of donors through the influence of epinephrine on Fbg conformation.     

A study of Choughs'' vocal repertoire: variability related to individuals, sexes and ages

Summary The calls uttered by Choughs (Pyrrhocorax pyrrhocorax) on Islay (S-W Scotland) were recorded during the breeding season. We analysed the vocal repertoire and the degree of call variation, among and within individuals. Eight structurally different calls were identified in Choughs' vocal repertoire. Significant differences in temporal and frequency variables of calls were found between fledglings and adults, whereas females' and males' calls turned out to differ only in two parameters of the commonest call type (chwee-ow). Despite sex-related differences in this call, partners appeared to utter similar versions of it, which suggests that mate vocal mimicry might occur. A certain degree of individuality, i.e. a greater among than within individuals variability, was found in three call types, but the reverse was found in the commonest call of the species. Accordingly, we hypothesise that this call might promote effective species recognition, whereas the other call types would be involved in individual recognition.

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Das stimmliche Repertoire der Alpenkrähe: individuelle, geschlechtliche und altersabhängige Variabilität

Zusammenfassung Während der Brutzeit 1996 wurde das Rufinventar von Alpenkrähen (Pyrrhocorax pyrrhocorax) auf der Insel Islay (SW Schottland) aufgenommen und hinsichtlich individueller Variation und Unterschieden zwischen verschiedenen Individuen analysiert. Acht grundsätzlich verschiedene Rufe wurden unterschieden. Signifikante Unterschiede bestanden zwischen flüggen Jungvögeln und Altvögeln in der Ruffrequenz und der zeitlichen Abfolge der Rufe. Männchen und Weibchen unterschieden sich dagegen nur geringfügig in dem am häufigsten vorgetragenen Ruf. Ungeachtet dieser geringen sexuellen Unterschiede riefen Paarpartner sehr ähnlich, was als Hinweise auf eine Stimmenmimikrie angesehen wird. In drei Ruftypen fand sich eine gewisse Individualität mit größerer Variablität zwischen verschiedenen als innerhalb eines Rufers, wogegen der häufigste Ruf von allen Individuen sehr ähnlich vorgetragen wurde. Es wird geschlossen, daß dieser Ruf der Arterkennung dient, die anderen dagegen mehr der individuellen Erkennung.

     

Bayesian analysis for nonlinear regression model under skewed errors,with application in growth curves

We have considered a Bayesian approach for the nonlinear regression model by replacing the normal distribution on the error term by some skewed distributions, which account for both skewness and heavy tails or skewness alone. The type of data considered in this paper concerns repeated measurements taken in time on a set of individuals. Such multiple observations on the same individual generally produce serially correlated outcomes. Thus, additionally, our model does allow for a correlation between observations made from the same individual. We have illustrated the procedure using a data set to study the growth curves of a clinic measurement of a group of pregnant women from an obstetrics clinic in Santiago, Chile. Parameter estimation and prediction were carried out using appropriate posterior simulation schemes based in Markov Chain Monte Carlo methods. Besides the deviance information criterion (DIC) and the conditional predictive ordinate (CPO), we suggest the use of proper scoring rules based on the posterior predictive distribution for comparing models. For our data set, all these criteria chose the skew‐t model as the best model for the errors. These DIC and CPO criteria are also validated, for the model proposed here, through a simulation study. As a conclusion of this study, the DIC criterion is not trustful for this kind of complex model.     

Platelet Recruitment Promotes Keratocyte Repopulation following Corneal Epithelial Abrasion in the Mouse

Corneal abrasion not only damages the epithelium but also induces stromal keratocyte death at the site of injury. While a coordinated cascade of inflammatory cell recruitment facilitates epithelial restoration, it is unclear if this cascade is necessary for keratocyte recovery. Since platelet and neutrophil (PMN) recruitment after corneal abrasion is beneficial to epithelial wound healing, we wanted to determine if these cells play a role in regulating keratocyte repopulation after epithelial abrasion. A 2 mm diameter central epithelial region was removed from the corneas of C57BL/6 wildtype (WT), P-selectin deficient (P-sel^-/-), and CD18 hypomorphic (CD18^hypo) mice using the Algerbrush II. Corneas were studied at 6h intervals out to 48h post-injury to evaluate platelet and PMN cell numbers; additional corneas were studied at 1, 4, 14, and 28 days post injury to evaluate keratocyte numbers. In WT mice, epithelial abrasion induced a loss of anterior central keratocytes and keratocyte recovery was rapid and incomplete, reaching ~70% of uninjured baseline values by 4 days post-injury but no further improvement at 28 days post-injury. Consistent with a beneficial role for platelets and PMNs in wound healing, keratocyte recovery was significantly depressed at 4 days post-injury (~30% of uninjured baseline) in P-sel^-/- mice, which are known to have impaired platelet and PMN recruitment after corneal abrasion. Passive transfer of platelets from WT, but not P-sel^-/-, into P-sel^-/- mice prior to injury restored anterior central keratocyte numbers at 4 days post-injury to P-sel^-/- uninjured baseline levels. While PMN infiltration in injured CD18^hypo mice was similar to injured WT mice, platelet recruitment was markedly decreased and anterior central keratocyte recovery was significantly reduced (~50% of baseline) at 4–28 days post-injury. Collectively, the data suggest platelets and platelet P-selectin are critical for efficient keratocyte recovery after corneal epithelial abrasion.     

Neisseria gonorrhoeae Modulates Immunity by Polarizing Human Macrophages to a M2 Profile

Current data suggest that Neisseria gonorrhoeae is able to suppress the protective immune response at different levels, such as B and T lymphocytes and antigen-presenting cells. The present report is focused on gonococcus evasion mechanism on macrophages (MФ) and its impact in the subsequent immune response. In response to various signals MФ may undergo classical-M1 (M1-MФ) or alternative-M2 (M2-MФ) activation. Until now there are no reports of the gonococcus effects on human MФ polarization. We assessed the phagocytic ability of monocyte-derived MФ (MDM) upon gonococcal infection by immunofluorescence and gentamicin protection experiments. Then, we evaluated cytokine profile and M1/M2 specific-surface markers on MФ challenged with N. gonorrhoeae and their proliferative effect on T cells. Our findings lead us to suggest N. gonorrhoeae stimulates a M2-MФ phenotype in which some of the M2b and none of the M1-MФ-associated markers are induced. Interestingly, N. gonorrhoeae exposure leads to upregulation of a Programmed Death Ligand 1 (PD-L1), widely known as an immunosuppressive molecule. Moreover, functional results showed that N. gonorrhoeae-treated MФ are unable to induce proliferation of human T-cells, suggesting a more likely regulatory phenotype. Taken together, our data show that N. gonorroheae interferes with MФ polarization. This study has important implications for understanding the mechanisms of clearance versus long-term persistence of N. gonorroheae infection and might be applicable for the development of new therapeutic strategies.     

Road Traffic Injury Trends in the City of Valledupar,Colombia. A Time Series Study from 2008 to 2012

Objective

To analyze the behavior temporal of road-traffic injuries (RTI) in Valledupar, Colombia from January 2008 to December 2012.

Methodology

An observational study was conducted based on records from the Colombian National Legal Medicine and Forensic Sciences Institute regional office in Valledupar. Different variables were analyzed, such as the injured person’s sex, age, education level, and type of road user; the timeframe, place and circumstances of crashes and the vehicles associated with the occurrence. Furthermore, a time series analysis was conducted using an auto-regressive integrated moving average.

Results

There were 105 events per month on an average, 64.9% of RTI involved men; 82.3% of the persons injured were from 18 to 59 years of age; the average age was 35.4 years of age; the road users most involved in RTI were motorcyclists (69%), followed by pedestrians (12%). 70% had up to upper-secondary education. Sunday was the day with the most RTI occurrences; 93% of the RTI occurred in the urban area. The time series showed a seasonal pattern and a significant trend effect. The modeling process verified the existence of both memory and extrinsic variables related.

Conclusions

An RTI occurrence pattern was identified, which showed an upward trend during the period analyzed. Motorcyclists were the main road users involved in RTI, which suggests the need to design and implement specific measures for that type of road user, from regulations for graduated licensing for young drivers to monitoring road user behavior for the promotion of road safety.     

Peruvian Red Uakaris (<Emphasis Type="Italic">Cacajao calvus ucayalii</Emphasis>) Are Not Flooded-Forest Specialists

In the literature, particularly in primatological books, the Peruvian red uakari (Cacajao calvus ucayalii) is generally considered as a species that is specialized on living in flooded forest, despite existing evidence to the contrary. Here we review all available information on habitats where Cacajao calvus ucayalii have been observed. Most sightings are from terra firme, including palm swamps, or from mixed habitats, including terra firme and flooded forest. Therefore, we conclude that the species is not a flooded-forest specialist, but is flexible in its habitat requirements and generally uses terra firme forests or a mixture of habitats. Proper recognition of habitat requirements is important for understanding the ecoethological adaptations of a species and for appropriate conservation measures.