Hope for Haiti?

Haiti, one of the world''s five poorest nations, gets international attention because of the number of refugees who leave by boat in search of a better future. The 80,000 inhabitants of Ile de la Gonave are neglected, even in Haiti--there is no government medical post, and facilities in the health posts run by missions are minimal. Typhoid and cholera epidemics threaten the island. Médecins Sans Frontières plans to send staff and supplies and train local health workers.     

Myocardial Hypertrophy in Athletes: Physiology or Pathology?

This paper includes data from the 11th century to the present day on athlete’s heart and its most controversial trait, myocardial hypertrophy. Four historical stages in the evolution of the concept of athlete’s heart are considered: physical, electrocardiographic, echocardiographic, and magnetic resonance imaging stages.     

Movement Control: Dedicated or Distributed?

Neural networks in which 'commands' spread 'horizontally' across multiple neurons have been believed to mediate motor pattern variation. A recent study shows that dedicated 'vertical' neural pathways can also underlie these variations.     

Trypanosomiasis and Tsetse Control with Insecticidal Pour-ons- Fact and Fiction?

Insecticidal pour-ons that are applied directly to cattle have been promoted widely in the last decade as a new means of controlling tsetse flies in Africa. Tsetse attracted to treated cattle get a lethal dose of insecticide and die. Following a large trial in Kenya, Matthew Baylis and Peter Stevenson argue here that the reduction in trypanosomiasis incidence caused by pour-ons exceeds that expected from the impact (if there is any) on the tsetse population and that certain other (as yet unknown) factors must also be involved.     

Hope for a broken heart?

Heart failure affects 23 million people worldwide and results from cardiac dysfunction characterized by decreased responsiveness to beta-adrenergic stimulation. A recent publication by W.J. Koch and colleagues highlights evidence for targeted beta-adrenergic receptor kinase (betaARK1) inhibition by gene transfer to improve contractile function and beta-adrenergic responsiveness in failing human myocardium. This proof-of-concept study has great importance for future heart failure therapy because it provides evidence for the therapeutic effectiveness of betaARK1 inhibition in failing human myocardium.     

Hope for a broken heart?

Heated debate has surrounded the issue of whether adult stem cells can differentiate into cardiac myocytes and contribute to the function of the heart. In this issue of Cell, demonstrate stem cells in the adult rat heart that differentiate into cardiac myocytes in vitro and, when injected into the adult rat heart, can reconstitute the injured myocardium and improve function. These findings should weigh heavily in future debates about the existence of stem cells in the adult heart and their capacity for functional repair after injury.     

The headcase Gene: Proliferation or Hormonal Control?

A new insertion allele of the hdc gene was isolated and described. The nucleotide sequence of the coding region had no detectable homology with genomic DNA of any other Drosophila species, except for D. mauritiana. Gene expression was found both in adult testes and ovaries and at embryonic and larval stages. This expression pattern exhibits a strong similarity to that of cell-cycle genes. In contrast to cycE (a typical cell-cycle gene), which leads to expression termination after in vivo culturing of the wing disk, hdc did not arrest expression. It is concluded thathdc is a species-specific differentiation gene, whose regulatory activity in the development of an organism differs from that of proliferation genes.     

Control or re-treat? Model-based guidelines for managing established plant invasions

Established invasions have wide-ranging negative impacts but constraints relating to invader detectability, cost, and efficacy of control may hamper management efforts. One choice that managers face is whether to target control efforts at heavily invaded areas that are sources of invasive propagules or to re-treat previously controlled areas that may be cheaper to control and in which local elimination may be achieved. We developed a mathematical model for the dynamics and control of a plant invasion to determine whether prioritizing heavily invaded or recently controlled areas better achieves each of two management objectives: minimizing the total number of detectable invaded sites (eradication) or heavily invaded sites only (beautification). We provide general guidelines for management by considering how invader traits, budgetary and time constraints, and control efficacy influence prioritization of control efforts and discuss their applicability to long-established invasive plants. For a wide range of invaders and control types, we find that prioritizing heavily-invaded sites performs better for meeting the beautification objective, while re-treating previously controlled sites better achieves eradication. However, combinations of invader traits can lead to the alternate strategy being favored for each management objective, while the optimal choice of management strategy can switch depending on the time horizon of control and annual budget. We summarize model findings to provide general guidelines for invasion managers on how to efficiently allocate limited resources based on invader life history, control cost, and mode of action.     

Hope for the Best or Prepare for the Worst? Towards a Spatial Cognitive Bias Test for Mice

Cognitive bias, the altered information processing resulting from the background emotional state of an individual, has been suggested as a promising new indicator of animal emotion. Comparable to anxious or depressed humans, animals in a putatively negative emotional state are more likely to judge an ambiguous stimulus as if it predicts a negative event, than those in positive states. The present study aimed to establish a cognitive bias test for mice based on a spatial judgment task and to apply it in a pilot study to serotonin transporter (5-HTT) knockout mice, a well-established mouse model for the study of anxiety- and depression-related behavior. In a first step, we validated that our setup can assess different expectations about the outcome of an ambiguous stimulus: mice having learned to expect something positive within a maze differed significantly in their behavior towards an unfamiliar location than animals having learned to expect something negative. In a second step, the use of spatial location as a discriminatory stimulus was confirmed by showing that mice interpret an ambiguous stimulus depending on its spatial location, with a position exactly midway between a positive and a negative reference point provoking the highest level of ambiguity. Finally, the anxiety- and depression-like phenotype of the 5-HTT knockout mouse model manifested - comparable to human conditions - in a trend for a negatively distorted interpretation of ambiguous information, albeit this effect was not statistically significant. The results suggest that the present cognitive bias test provides a useful basis to study the emotional state in mice, which may not only increase the translational value of animal models in the study of human affective disorders, but which is also a central objective of animal welfare research.     

Virus adaptation to quantitative plant resistance: erosion or breakdown?

Adaptation of populations to new environments is frequently costly due to trade‐offs between life history traits, and consequently, parasites are expected to be locally adapted to sympatric hosts. Also, during adaptation to the host, an increase in parasite fitness could have direct consequences on its aggressiveness (i.e. the quantity of damages caused to the host by the virus). These two phenomena have been observed in the context of pathogen adaptation to host's qualitative and monogenic resistances. However, the ability of pathogens to adapt to quantitative polygenic plant resistances and the consequences of these potential adaptations on other pathogen life history traits remain to be evaluated. Potato virus Y and two pepper genotypes (one susceptible and one with quantitative resistance) were used, and experimental evolutions showed that adaptation to a quantitative resistance was possible and resulted in resistance breakdown. This adaptation was associated to a fitness cost on the susceptible cultivar, but had no consequence either in terms of aggressiveness, which could be explained by a high tolerance level, or in terms of aphid transmission efficiency. We concluded that quantitative resistances are not necessarily durable but management strategies mixing susceptible and resistant cultivars in space and/or in time should be useful to preserve their efficiency.