Ischemic Tolerance Protects the Rat Retina from Glaucomatous Damage

Glaucoma is a leading cause of acquired blindness which may involve an ischemic-like insult to retinal ganglion cells and optic nerve head. We investigated the effect of a weekly application of brief ischemia pulses (ischemic conditioning) on the rat retinal damage induced by experimental glaucoma. Glaucoma was induced by weekly injections of chondroitin sulfate (CS) in the rat eye anterior chamber. Retinal ischemia was induced by increasing intraocular pressure to 120 mmHg for 5 min; this maneuver started after 6 weekly injections of vehicle or CS and was weekly repeated in one eye, while the contralateral eye was submitted to a sham procedure. Glaucoma was evaluated in terms of: i) intraocular pressure (IOP), ii) retinal function (electroretinogram (ERG)), iii) visual pathway function (visual evoked potentials, (VEPs)) iv) histology of the retina and optic nerve head. Retinal thiobarbituric acid substances levels were assessed as an index of lipid peroxidation. Ischemic conditioning significantly preserved ERG, VEPs, as well as retinal and optic nerve head structure from glaucomatous damage, without changes in IOP. Moreover, ischemia pulses abrogated the increase in lipid peroxidation induced by experimental glaucoma. These results indicate that induction of ischemic tolerance could constitute a fertile avenue for the development of new therapeutic strategies in glaucoma treatment

The relationship between stimulus intensity and response amplitude for the photopic negative response of the flash electroretinogram

The aim of this study was to investigate the relationship between stimulus intensity and response amplitude for the photopic negative response (PhNR) of the flash ERG. Specific aims were (i) to determine whether a generalized Naka-Rushton function provided a good fit to the intensity-response data and (ii) to determine the variability of the parameters of the best-fitting Naka-Rushton models. Electroretinograms were recorded in 18 participants, on two occasions, using both DTL fibre and skin active electrodes, in response to Ganzfeld red stimuli (Lee filter "terry red") ranging in stimulus strength from -1.30 to 0.53 log cd.s.m(-2) (0.28-2.11 log phot td.s) presented over a steady blue background (Schott glass filter BG28; 3.9 log scot td). PhNR amplitude was measured from b-wave peak and from pre-stimulus baseline. The Naka-Rushton function was fitted to all intensity-response data, and parameters, 'n', 'Vmax' and 'K' were obtained. Coefficients of variation (CoV), and inter-ocular and inter-session limits of agreement (LoA) were calculated for both Naka-Rushton parameters. A generalized Naka-Rushton function was found to provide a good fit to the intensity-response data, except at the highest stimulus intensity, where a reduction in amplitude occurred in many individuals. The 'Vmax' parameter was less variable than 'K' for all intensity-response data. Variability was lower for DTL than skin electrodes, and for peak-to-trough PhNR measurements, compared to baseline-to-trough. This study has demonstrated for the first time that the Naka-Rushton model provides a useful means of quantifying the intensity-response relationship of the PhNR

Young carers in Germany: to live on as normal as possible – a grounded theory study

<p>Abstract</p> <p>Background</p> <p>In contrast to a growing body of research on the situation of adult family care givers, in Germany hardly anything is known about the situation of children and teenagers who are involved in the care of their relatives.</p> <p>Methods</p> <p>In this Grounded Theory study 81 semi structured interviews have been carried out with children and their parents in 34 families, in which one member is chronically ill. 41 children and 41 parents participated and the sample is heterogeneous and diverse.</p> <p>Results</p> <p>On the one hand, there is the phenomenon 'keeping the family together", which describes how families themselves cope with the chronic illness and also, which tasks to what extent are being shifted and redistributed within the family in order to manage daily life. Influencing factors, the children's motives as well as the impact on the children also belong to this phenomenon. The second phenomenon 'to live a normal course of life' describes concrete wishes and expectations of support for the family to manage the hindered daily life. These two phenomena linked together constitute the 'model of experience and construction of familial care, in which children take over an active role'.</p> <p>Conclusion</p> <p>It will be discussed, that the more families are in dire need of support, the more their distress becomes invisible, furthermore, that management of chronic illness is a process, in which the entire family is involved, and thus needs to be considered, and finally, that young carer's relief is not possible without relief of their parents.</p

Specific Roles of Akt iso Forms in Apoptosis and Axon Growth Regulation in Neurons

Akt is a member of the AGC kinase family and consists of three isoforms. As one of the major regulators of the class I PI3 kinase pathway, it has a key role in the control of cell metabolism, growth, and survival. Although it has been extensively studied in the nervous system, we have only a faint knowledge of the specific role of each isoform in differentiated neurons. Here, we have used both cortical and hippocampal neuronal cultures to analyse their function. We characterized the expression and function of Akt isoforms, and some of their substrates along different stages of neuronal development using a specific shRNA approach to elucidate the involvement of each isoform in neuron viability, axon development, and cell signalling. Our results suggest that three Akt isoforms show substantial compensation in many processes. However, the disruption of Akt2 and Akt3 significantly reduced neuron viability and axon length. These changes correlated with a tendency to increase in active caspase 3 and a decrease in the phosphorylation of some elements of the mTORC1 pathway. Indeed, the decrease of Akt2 and more evident the inhibition of Akt3 reduced the expression and phosphorylation of S6. All these data indicate that Akt2 and Akt3 specifically regulate some aspects of apoptosis and cell growth in cultured neurons and may contribute to the understanding of mechanisms of neuron death and pathologies that show deregulated growth

Genome-wide association study reveals a set of genes associated with resistance to the Mediterranean corn borer (Sesamia nonagrioides L.) in a maize diversity panel

[Background] Corn borers are the primary maize pest; their feeding on the pith results in stem damage and yield losses. In this study, we performed a genome-wide association study (GWAS) to identify SNPs associated with resistance to Mediterranean corn borer in a maize diversity panel using a set of more than 240,000 SNPs.[Results] Twenty five SNPs were significantly associated with three resistance traits: 10 were significantly associated with tunnel length, 4 with stem damage, and 11 with kernel resistance. Allelic variation at each significant SNP was associated with from 6 to 9% of the phenotypic variance. A set of genes containing or physically close to these SNPs are proposed as candidate genes for borer resistance, supported by their involvement in plant defense-related mechanisms in previously published evidence. The linkage disequilibrium decayed (r2 < 0.10) rapidly within short distance, suggesting high resolution of GWAS associations.[Conclusions] Most of the candidate genes found in this study are part of signaling pathways, others act as regulator of expression under biotic stress condition, and a few genes are encoding enzymes with antibiotic effect against insects such as the cystatin1 gene and the defensin proteins. These findings contribute to the understanding the complex relationship between plant-insect interactions.This work was supported by the National Plan for Research and Development of Spain (projects AGL2012-33415). L.F. Samayoa acknowledges a contract JAE-Predoc from the Spanish Council for Scientific Research (CSIC).Peer reviewe

Influência do processo de familiarização para avaliação da força muscular em testes de 1-RM Influencia del proceso de familiarizacion para evaluación de la fuerza muscular en tests de 1-RM Influence of familiarization process on muscular strength assessment in 1-RM tests

Embora testes de uma repetição máxima (1-RM) sejam freqüentemente utilizados para a avaliação da força muscular, acredita-se que os resultados obtidos possam ser afetados pela falta de familiarização prévia, até mesmo em sujeitos com experiência em exercícios com pesos. Assim, o objetivo deste estudo foi investigar o impacto do processo de familiarização para avaliação da força muscular em testes de 1-RM. Para tanto, 21 homens (24,5 &plusmn; 3,8 anos), aparentemente saudáveis, com experiência prévia de pelo menos seis meses em treinamento com pesos, foram submetidos a testes repetitivos de 1-RM nos exercícios supino em banco horizontal, agachamento e rosca direta de bíceps. Os testes foram executados em quatro sessões, intervaladas a cada 48-72 horas. Um número máximo de três tentativas, com intervalo de três a cinco minutos para recuperação, foi utilizado em cada exercício, nas quatro sessões de testagem. ANOVA para medidas repetidas, seguida pelo teste post hoc de Tukey, quando p < 0,05, foi utilizada para o tratamento dos dados. Aumentos significantes na força muscular (p < 0,01) foram encontrados nos três exercícios analisados entre a primeira e a quarta sessão de familiarização (2,4% no supino em banco horizontal, 3,4% no agachamento e 5,4% na rosca direta de bíceps). Todavia, nenhuma diferença estatisticamente significante foi encontrada entre a segunda e a quarta sessão de familiarização na rosca direta de bíceps (p > 0,05), bem como entre a terceira e a quarta sessão no supino em banco horizontal e no agachamento (p > 0,05). Os resultados indicam que a falta de familiarização prévia com testes de 1-RM pode comprometer a avaliação da força muscular. Portanto, sugere-se, para avaliação mais acurada da força muscular mediante testes de 1-RM, a execução de duas a três sessões de familiarização em homens adultos com experiência em exercícios com pesos.<br>Embora la utilización de tests de una repetición máxima (1-RM) es frecuente para la evaluación de la fuerza muscular, se acredita que los resultados obtenidos puedan ser afectados por la falta de familiarización previa, hasta mismo en sujetos con experiencia en ejercicios con pesos. Asi, el objetivo de este estudio fué investigar el impacto del proceso de familiarización para evaluación de la fuerza muscular en tests de 1-RM. Por lo tanto, 21 hombres (24,5 &plusmn; 3,8 años), aparentemente saludables con experiencia previa de por lo menos seis meses de entrenamiento con pesos, fueron sometidos a tests reptitivos de 1-RM en los ejercicios supino en banco horizontal, agachamiento y rosca directa de bíceps. Los tests fueran ejecutados en cuatro sesiones, intervaladas en cada 48-72 horas. Un número máximo de tres tentativas, con intérvalo de tres a cinco minutos para recuperación, fué utilizado en cada ejercicio, en las cuatro sessiones de testeo. ANOVA se utilizó para medidas repetidas, seguida por el test post hoc de Tukey, cuando p < 0,05, fué utilizada para el tratamiento de los datos. Aumentos significantes en la fuerza muscular (p < 0,01) fueron encontrados los tres ejercicios analizados entre la primera y la cuarta sesión de familiarización (2,4% en supino en banco horizontal, 3,4% en agachamiento y 5,4% en la rosca directa del bíceps). Todavía, ninguna diferencia estadísticamente significativamente fuera encontrada entre la segunda y la cuarta sesión de familiarización en la rosca directa de bíceps (p > 0,05), bien con entre la tercera y la cuarta sesión en el supino en el banco horizontal y en el agachamiento (p > 0,05). Los resultados indican que la falta de familiarización previa con tests de 1-RM puede comprometer la evaluación de la fuerza muscular. Por lo tanto, se sugiere para la evaluación mas acurada de la fuerza muscular mediante tests de 1-RM la ejecución de dos a tres sesiones de familiarización en los hombres adultos con experiencia en ejercicios con pesos.<br>Although the use of maximum repetition tests (1-RM) is frequent for assessment of the muscular strength, one believes that the results obtained may be affected by the lack of previous familiarization, even in skilled subjects in exercises with weights. Thus, the objective of this study was to investigate the impact of the familiarization process on the muscular strength assessment in 1-RM tests. To do so, 21 men (24.5 &plusmn; 3.8 years of age), apparently healthy and with previous experience of at least six months on weight training, were submitted to repetitive tests of 1-RM in bench press, squat, and arm curl exercises. The tests were performed in four sessions with intervals every 48-72 hours. A maximum number of three attempts with 3-5 minutes interval for recovery was used in each exercise in the four testing sessions. The analysis of variance ANOVA for repeated measures followed by the post hoc Tukey test when p < 0.05 were used for the data treatment. Significant increases on the muscular strength (p < 0.01) were found in the three exercises analyzed between the first and the fourth familiarization session (2.4% in bench press, 3.4% in squat, and 5.4% in the arm curl). However, no statistically significant difference was found between the second and fourth familiarization sessions in the arm curl (p > 0.05) as well as between the third and fourth sessions in the bench press and squat (p > 0.05). The results indicate that the lack of previous familiarization with 1-RM tests may impair the muscular strength evaluation. Therefore, the performance of two to three familiarization sessions in adult men with previous experience with weightlifting is suggested for a more accurate muscular strength assessment by means of the 1-RM tests