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Cycling ergometer protocols are commonly integrated with a virtual reality environment (VRE), especially because of its static position that also allows multiple exercise experiments. Concerning VRE scenarios, visually delayed situations like the ones produced at excessive low update rates can also affect the sense of presence and physiological responses. However, the main interface between the subject and a cycling VRE is the power applied over the crank, and there are only a few experiments to evaluate the effect of delayed situations on this particular interface. Thus, this work aims to investigate the effects of the power update rate (PUR) over the subject's performance on an avatar-based simulator during a drafting task. A custom cycling VRE was built, and 21 male recreational cyclists (175.9 ± 7.5 cm; 76.5 ± 13.9 kg) were tested at six different PUR levels from 100 to 3000 ms. As a result, PUR affects performance scores (virtual distance, efficiency, and heart rate, p < 0.01) at the given VRE conditions. The case-by-case analysis of the groups reveals that higher update rates always lead to a statistical equivalent or superior performance. Nevertheless, no parameter shows any group difference between 500 ms and lower PUR. These results suggest that virtual cycling protocols should consider PUR and other delay-related mechanisms as possible intervening factors over physiological responses and performance scores. [ABSTRACT FROM AUTHOR]

ABCC2 (MRP2, cMOAT) expression has been implicated in cisplatin resistance in vitro. In mice, cisplatin disposition and toxicity were unaffected by Abcc2 knockout (Abcc2−/−). Moreover, in cancer patients (n = 237), cisplatin pharmacokinetics (P > 0.12) and efficacy (P > 0.41) were not associated with seven of the single-nucleotide polymorphisms (SNPs) in ABCC2. These SNPs were also not correlated with ABCC2 expression in the NCI60 panel (P > 0.26) or with cisplatin-induced cytotoxicity (P = 0.21). These findings highlight the importance of verifying drug-transporter interactions with in vitro tests in humans. [ABSTRACT FROM AUTHOR]

Introduction/objectives: The serine/threonine kinase homeodomain-interacting protein kinase 2 (HIPK2) is a co-regulator of an increasing number of transcription factors and cofactors involved in DNA damage response and development. We and others have cloned HIPK2 as an interactor of the p53 oncosuppressor, and have studied the role of this interaction in cell response to stress. Nevertheless, our original cloning of HIPK2 as a p53-binding protein, was aimed at discovering partners of p53 involved in cell differentiation and development, still controversial p53 functions. To this aim, we used p53 as bait in yeast two-hybrid screening of a cDNA library from mouse embryo (day 11 postcoitus) when p53 is highly expressed. Methods and results: In this study, we directly explored whether HIPK2 and p53 cooperate in cell differentiation. By measuring HIPK2 expression and activity in skeletal muscle and haemopoietic differentiation, we observed inverse behaviour of HIPK2 and p53 – excluding cooperation activity of these two factors in this event. However, by HIPK2 depletion experiments, we showed that drastic HIPK2 suppression promotes cell-cycle arrest by induction of the cyclin-dependent kinase inhibitor p21 Waf-1/ Cip-1. HIPK2 activity is independent of DNA damage and takes place in cell-cycle-arresting conditions, such as terminal differentiation, growth factor deprivation, and G0 resting. Conclusions: HIPK2 was found to be involved in cell-cycle regulation dependent on p21 Waf-1/ Cip-1 and independent of DNA damage. [ABSTRACT FROM AUTHOR]

This paper reports the results of the cross-sectional phase of a long-term follow-up investigation, carried out on a sample representative of the broad population of HIV-1 infected patients, with the objective of evaluating the possible neurocognitive effects of zidovudine and 2′, 3′-dideoxyinosine, compared to a group of people who refused antiretroviral therapy. The sample was composed of 88 people, 42 of whom were treated with ZDV at a daily dose of 500–600 mg, 19 with ddI at a daily dose of 400 mg, and 27 with no therapy. To assess the relevance of different antiretroviral therapies on cognitive performance adjusting for demographic and clinical characteristics, a stepwise logistic regression analysis was performed with neuropsychological performance as the dependent variable and age, education, sex, at-risk behaviour, CD4 count, presence of prominent depressive and anxious symptoms, HIV-1 serostatus and type of antiretroviral treatment as independent variables. The results confirm that people with AIDS and AIDS-related complex treated with ZDV and ddI show a better neuropsychological performance when compared to non-treated patients. By examining the mean performance on each of the previous neuropsychological tests, we found that the most impaired functions in untreated patients were related to short-term memory, long-term memory, vocational competence, and ultimate adjustment. [ABSTRACT FROM AUTHOR]

Abstract. The response of Triatoma infestans (Klug) to odours left behind by walking insects was analysed. The insects aggregated on papers marked with putative chemical footprints in the absence of other assembling chemical signals. Contact of the receptor insect with the treated surface was necessary to elicit the response because the signal was not able to attract insects, only to arrest them on marked surfaces. These requirements contrast with other chemical aggregation signals of triatomines that attract the insect and involve olfactory responses. By washing the cuticle of the insects with hexane and impregnating papers with the extract, a response was evoked in test insects similar to that elicited by papers on which insects had walked. The biological role of this novel aggregation factor is discussed in relation to other assembling signals of different origin. [ABSTRACT FROM AUTHOR]

The effect of the addition of egg yolk to a blood meal on the development of Triatoma infestans (Klug) was analysed. Egg yolk was added in different quantities to heparinized, citrated or defibrinated bovine blood, which was offered in an artificial feeder. Control groups were fed on either non-supplemented blood or hen in vivo. Results indicated that the addition of egg yolk to a blood meal reduced the intermoult interval and the moult success increased when egg yolk was added to the diet. The effect was more dramatic for the less suitable diets, as follows: citrated blood > defibrinated blood > heparinized blood. The minimal and most effective concentration of egg yolk in the diet was 10% v/v. When the egg yolk was centrifuged in a density-gradient, fractions with different performance could be obtained; middleweight fractions, but not the heaviest or lightest ones reproduced the observed effects of the whole yolk at the corresponding concentration. Growth rate and moulting success showed to be differentially affected by the diets and the growth performance of in vivo-fed experimental groups could be completely reproduced by adding yolk to the blood diets offered in artificial feeders. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented about the role of interferon-alpha in treating patients with chronic hepatitis.

Mutations in amyloid precursor protein (APP), and presenilin-1 and presenilin-2 (PS1 and PS2) have causally been implicated in Familial Alzheimer's Disease (FAD), but the mechanistic link between the mutations and the early onset of neurodegeneration is still debated. Although no consensus has yet been reached, most data suggest that both FAD-linked PS mutants and endogenous PSs are involved in cellular Ca2+ homeostasis. We here investigated subcellular Ca2+ handling in primary neuronal cultures and acute brain slices from wild type and transgenic mice carrying the FAD-linked PS2-N141I mutation, either alone or in the presence of the APP Swedish mutation. Compared with wild type, both types of transgenic neurons show a similar reduction in endoplasmic reticulum (ER) Ca2+ content and decreased response to metabotropic agonists, albeit increased Ca2+ release induced by caffeine. In both transgenic neurons, we also observed a higher ER-mitochondria juxtaposition that favors increased mitochondrial Ca2+ uptake upon ER Ca2+ release. A model is described that integrates into a unifying hypothesis the contradictory effects on Ca2+ homeostasis of different PS mutations and points to the relevance of these findings in neurodegeneration and aging., (© 2012 The Authors. Aging Cell © 2012 Blackwell Publishing Ltd/Anatomical Society of Great Britain and Ireland.)

Hemodynamic instability, mostly due to vertical lifting of the heart, is usually observed during beating-heart surgical procedures. However, some hemodynamic parameters, such as coronary blood flow, are not routinely measured. A digital computer model of the circulation able to simulate and analyze the effects of heart lifting and the Trendelenburg maneuver, and thus supply detailed hemodynamic information to the clinicians would provide a useful analytical tool. A lumped parameters model of the circulation was applied to both beta-blocked and not beta-blocked pigs. The results confirmed a drop of cardiac output and coronary flow during heart lifting and a rise of both variables after the Trendelenburg maneuver for beta-blocked animals. In not beta-blocked pigs, the analysis was more complex but the model reproduced experimental data and permitted coronary flow to be estimated. These results showed the feasibility of numerical simulation for specific circulatory conditions encountered during beating-heart surgery.