Saving Mothers' Lives 2006-2008

The eighth Report of the Confidential Enquiries into Maternal Deaths in the UK investigates the deaths of 261 women who died in the triennium 2006-08, from causes directly or indirectly related to pregnancy. The full Report is available for purchase or download from the Centre for Maternal and Child Enquiries (CMACE; www.cmace.org.uk). Although every maternal death is a tragedy, particularly where avoidable factors were identified by the Enquiry process, the overall picture is encouraging. The maternal death rate in the UK continues to decline despite increasing pressures on maternity services and a changing maternal population. For the first time there has been a reduction in the inequalities gap between women living in different socio-economic circumstances, and timely production of guidelines and tools appears to have helped clinical staff to deliver improved clinical care.

Evolution of foraging behaviour in response to chronic malnutrition in Drosophila melanogaster.

Chronic exposure to food of low quality may exert conflicting selection pressures on foraging behaviour. On the one hand, more active search behaviour may allow the animal to find patches with slightly better, or more, food; on the other hand, such active foraging is energetically costly, and thus may be opposed by selection for energetic efficiency. Here, we test these alternative hypotheses in Drosophila larvae. We show that populations which experimentally evolved improved tolerance to larval chronic malnutrition have shorter foraging path length than unselected control populations. A behavioural polymorphism in foraging path length (the rover-sitter polymorphism) exists in nature and is attributed to the foraging locus (for). We show that a sitter strain (for(s2)) survives better on the poor food than the rover strain (for(R)), confirming that the sitter foraging strategy is advantageous under malnutrition. Larvae of the selected and control populations did not differ in global for expression. However, a quantitative complementation test suggests that the for locus may have contributed to the adaptation to poor food in one of the selected populations, either through a change in for allele frequencies, or by interacting epistatically with alleles at other loci. Irrespective of its genetic basis, our results provide two independent lines of evidence that sitter-like foraging behaviour is favoured under chronic larval malnutrition.

Coadaptation and malaria control

Malaria emerges from a disequilibrium of the system 'human-plasmodium-mosquito' (HPM). If the equilibrium is maintained, malaria does not ensue and the result is asymptomatic plasmodium infection. The relationships among the components of the system involve coadaptive linkages that lead to equilibrium. A vast body of evidence supports this assumption, including the strategies involved in the relationships between plasmodium and human and mosquito immune systems, and the emergence of resistance of plasmodia to antimalarial drugs and of mosquitoes to insecticides. Coadaptive strategies for malaria control are based on the following principles: (1) the system HPM is composed of three highly complex and dynamic components, whose interplay involves coadaptive linkages that tend to maintain the equilibrium of the system; (2) human and mosquito immune systems play a central role in the coadaptive interplay with plasmodium, and hence, in the mainten-ance of the system's equilibrium; the under- or overfunction of human immune system may result in malaria and influence its severity; (3) coadaptation depends on genetic and epigenetic phenomena occurring at the interfaces of the components of the system, and may involve exchange of infectrons (genes or gene fragments) between the partners; (4) plasmodia and mosquitoes have been submitted to selective pressures, leading to adaptation, for an extremely long while and are, therefore, endowed with the capacity to circumvent both natural (immunity) and artificial (drugs, insecticides, vaccines) measures aiming at destroying them; (5) since malaria represents disequilibrium of the system HPM, its control should aim at maintaining or restoring this equilibrium; (6) the disequilibrium of integrated systems involves the disequilibrium of their components, therefore the maintenance or restoration of the system's equilibrium depend on the adoption of integrated and coordinated measures acting on all components, that means, panadaptive strategies. Coadaptive strategies for malaria control should consider that: (1) host immune response has to be induced, since without it, no coadaptation is attained; (2) the immune response has to be sustained and efficient enough to avoid plasmodium overgrowth; (3) the immune response should not destroy all parasites; (4) the immune response has to be well controlled in order to not harm the host. These conditions are mostly influenced by antimalarial drugs, and should also be taken into account for the development of coadaptive malaria vaccines.

Thyroid hormone enhances transected axonal regeneration and muscle reinnervation following rat sciatic nerve injury.

Improvement of nerve regeneration and functional recovery following nerve injury is a challenging problem in clinical research. We have already shown that following rat sciatic nerve transection, the local administration of triiodothyronine (T3) significantly increased the number and the myelination of regenerated axons. Functional recovery is a sum of the number of regenerated axons and reinnervation of denervated peripheral targets. In the present study, we investigated whether the increased number of regenerated axons by T3-treatment is linked to improved reinnervation of hind limb muscles. After transection of rat sciatic nerves, silicone or biodegradable nerve guides were implanted and filled with either T3 or phosphate buffer solution (PBS). Neuromuscular junctions (NMJs) were analyzed on gastrocnemius and plantar muscle sections stained with rhodamine alpha-bungarotoxin and neurofilament antibody. Four weeks after surgery, most end-plates (EPs) of operated limbs were still denervated and no effect of T3 on muscle reinnervation was detected at this stage of nerve repair. In contrast, after 14 weeks of nerve regeneration, T3 clearly enhanced the reinnervation of gastrocnemius and plantar EPs, demonstrated by significantly higher recovery of size and shape complexity of reinnervated EPs and also by increased acetylcholine receptor (AChRs) density on post synaptic membranes compared to PBS-treated EPs. The stimulating effect of T3 on EP reinnervation is confirmed by a higher index of compound muscle action potentials recorded in gastrocnemius muscles. In conclusion, our results provide for the first time strong evidence that T3 enhances the restoration of NMJ structure and improves synaptic transmission.

Personality and melanin-based colouration traits in barn owls, tawny owl and kestrels

Individuals need to adapt to their local environment in order to survive. When selection pressures differ in local populations, polymorphism can evolve. Colour polymorphism is one of the most obvious polymorphisms since it is readily observable. Different sources of colouration exist, but melanin-based colouration is one of the most common in birds. The melanocortin system produces this colouration and because the melanocortin system has pleiotropic effects on behavioural and physiological traits, it is a good candidate to be an underlying mechanism to explain the maintenance of colour polymorphism. In this thesis I studied three different raptors which all display melanin-based colouration; barn owls (Tyto alba), tawny owls (Strix aluco) and Eurasian kestrels (Falco tinnunculus). The main question was if there was a relationship between melanin-based colouration and individual behavioural differences. The underlying hypothesis is that colour could be a signal of certain adaptive traits. Our goal was to find evolutionary explanations for the persistence of colour polymorphism. I found that nestling kestrels and barn owls differ in anti-predatory behaviour, with respect to their melanic colouration (chapters 1 and 2). Darker individuals show less reaction to human handling, but in kestrels aggression and colouration are related in opposite ways than in barn owls. More reddish barn owls travel greater distances in natal dispersal and this behaviour is repeatable between parents and same sex offspring (chapter 3). Dark reddish tawny owls defend their nests more intensely against intruders and appear to suffer less from nest predation (chapter 4). Finally I show that polymorphism in the Melanocortin 1 receptor gene (MC1R), which is strongly correlated with reddish colouration in the barn owl, is related to natal dispersal distance, providing a first indication for a genetic basis of the relation between this behaviour and colouration (chapter 5). My results demonstrate a clear link between melanin-based colouration and animal personality traits. I demonstrated this relation in three different species, which shows there is most likely a general underlying mechanism responsible. Different predation pressures might have shaped the reactions to predation, but also differences in sex-related colouration. Male-like and female-like colouration might signal more or less aggressive behaviour. Fluctuating environmental conditions might cause different individual strategies to produce equal reproductive success. The melanocortin system with its pleiotropic effects might be an underlying mechanism, as suggested by the results from the genetic polymorphism, the similar results found in these three species and by the similar relations reported in other species. This thesis demonstrates that colouration and individual differences are correlated and it provides the first glimpse of an underlying system. We can now conduct a more directed search for underlying mechanisms and evolutionary explanations with the use of quantitative genetic methods.

The demographic benefits of belligerence and bravery: defeated group repopulation or victorious group size expansion?

Intraspecific coalitional aggression between groups of individuals is a widespread trait in the animal world. It occurs in invertebrates and vertebrates, and is prevalent in humans. What are the conditions under which coalitional aggression evolves in natural populations? In this article, I develop a mathematical model delineating conditions where natural selection can favor the coevolution of belligerence and bravery between small-scale societies. Belligerence increases an actor's group probability of trying to conquer another group and bravery increase the actors's group probability of defeating an attacked group. The model takes into account two different types of demographic scenarios that may lead to the coevolution of belligerence and bravery. Under the first, the fitness benefits driving the coevolution of belligerence and bravery come through the repopulation of defeated groups by fission of victorious ones. Under the second demographic scenario, the fitness benefits come through a temporary increase in the local carrying capacity of victorious groups, after transfer of resources from defeated groups to victorious ones. The analysis of the model suggests that the selective pressures on belligerence and bravery are stronger when defeated groups can be repopulated by victorious ones. The analysis also suggests that, depending on the shape of the contest success function, costly bravery can evolve in groups of any size.

Vaporization behaviour and some thermodynamic properties of the Pd-In, Pd-Pb, Pd-Sn systems

In this study, the vaporization behaviour of solid Pd-rich phases in the Pd-Pb, Pd-In and Pd-Sn systems was investigated by Knudsen-effusion-cell coupled with mass-spectrometry. The Pb, Pd, In vapor pressures [no Sn(g) has been detected in the vapor of Pd-Sn system] were evaluated in the temperatures range 1190-1563 K from the ion intensities measured over two-phases regions. Thermodynamic quantities were derived from vapor pressure data. In particular, for the Pd-Sn binary, the intermediate phase Pd7Sn2, the existence of which has been recently proposed, has been studied here for the first time. Furthermore, preliminary thermochemical data are presented for the diatomic intermetallic molecules PdSn and PdPb, which have been for the first time identified in the vapors in equilibrium over liquid solutions of appropriate composition at higher temperatures (1935-2025 K). (C) 2000 Elsevier Science Ltd. All rights reserved.

Isolated office hypertension: a prehypertensive state?

OBJECTIVE AND METHOD: Isolated office hypertension, defined as hypertensive blood pressure values in a medical setting but normal self-measured or ambulatory-recorded blood pressures, is frequently encountered in clinical practice. Yet, whether this condition represents a transient state in the development of a sustained ambulatory hypertension is still unknown as no long-term analysis of the evolution of ambulatory blood pressure has been carried out in patients with isolated office hypertension. To evaluate whether such patients should be considered as truly normotensive or hypertensive, we have studied the long-term changes in office and ambulatory blood pressures in 81 patients in whom isolated office hypertension was observed between 1982 and 1988. RESULTS: After a 5-6 year follow-up, 60 of the 81 patients had a mean 12 h daytime ambulatory blood pressure greater than 140/90 mmHg, suggesting an evolution towards ambulatory hypertension. The development of hypertension could not be predicted on the basis of the follow-up office blood pressures as these tended to decrease during the follow-up period. CONCLUSIONS: The results of this study suggest that patients with isolated office hypertension should not be considered as truly normotensive individuals. Hence, these patients require a careful medical follow-up. Office blood pressure readings alone, however, do not appear to provide a good indicator of the long-term outcome of isolated office hypertension.

Improving influenza vaccination rates in the elderly.

BACKGROUND: Vaccination coverage for influenza in the elderly remains low when the physician is the only person responsible for immunization. Integration of other health care workers may improve the coverage rate of at-risk groups. OBJECTIVES: To estimate vaccination coverage rate by using a strategy based on the systematic intervention of a health care professional proposing vaccination before the doctor's consultation, to evaluate the changes in coverage rates before and after introduction of this strategy, and to assess the feasibility of this intervention and the achieved coverage rate in family physician offices. STUDY DESIGN: Prospective study in a medical outpatient clinic and 5 family physician practices in Switzerland. POPULATION: Participants consisted of all patients 65 years or older attending a medical outpatient clinic during the vaccination period in 1999 (n = 401), patients 65 years or older regularly followed at a medical outpatient clinic in 1998 and 1999 (n = 195), and patients 65 years or older presenting to 5 family physician offices in 1999 (n = 598). OUTCOME MEASURED: Rates of vaccination coverage. RESULTS: Among all participants, vaccination coverage rates in 1999 were 85% at the medical outpatient clinic and 83% in family physician offices. Among participants regularly followed at the medical outpatient clinic, vaccination coverage increased from 48% in 1998 to 76% in 1999. Rates of refusal were 9% at the medical outpatient clinic and 14% in the family physician offices. CONCLUSIONS: The systematic intervention of a health care professional to suggest vaccination before the doctor's visit is an effective measure to achieve high coverage rate. Such a strategy also improves outpatient clinic or private practice efficiency by reducing pressures on physicians.

The renin-angiotensin system and arterial wall behavior.

To assess the behavior of the arterial wall in hypertensive patients, we developed a noninvasive ultrasonic device. Simultaneous recordings of internal diameter and blood pressure over the whole cardiac cycle are used to establish compliance-pressure curves. Blood pressure, which is a co-determinant of compliance, is thus taken into account. This method allows one to compare arteries from patients with different blood pressures. Arterial compliance and distensibility were first investigated in healthy young volunteers administered either lisinopril (20 mg), atenolol (100 mg) or nitrendipine (20 mg) once a day. After 8 days of treatment, only lisinopril was found to increase arterial compliance. Subsequently, we compared arterial diameter- and distensibility-pressure curves from newly diagnosed and untreated hypertensive patients with those of matched normotensive control patients. Diameter-pressure curves did not differ significantly between the groups and distensibility was not reduced. Similar findings were later obtained in an animal model, when mechanical properties of carotid arteries were compared between spontaneously hypertensive rats and normotensive counterparts (Wistar-Kyoto rats). These results, although interesting by providing noninvasive information on the elastic response of the wall, call for further development of the technique to be able to measure arterial wall thickness. Stress-strain relationship could ultimately be established to thoroughly characterize physical properties of blood vessel walls.

Estudi de la vegetació dels camins de ronda de Palafrugell: impacte i mesures de control de la flora introduïda

El treball consisteix en un estudi aprofundit de la vegetació que configura el veritable ecosistema mediterrani de la costa de Palafrugell (inventaris de les espècies al.lòctones i les autòctones) fent una sèrie de propostes de millora de les zones més degradades intentant evitar la colonització de les espècies no desitjables amb la posterior elaboració d’un llistat d’espècies aconsellables per plantar en espais públics enjardinats

Evolutionary histories of expanded peptidase families in Schistosoma mansoni

Schistosoma mansoni is one of the three main causative agents of human schistosomiasis, a major health problem with a vast socio-economic impact. Recent advances in the proteomic analysis of schistosomes have revealed that peptidases are the main virulence factors involved in the pathogenesis of this disease. In this context, evolutionary studies can be applied to identify peptidase families that have been expanded in genomes over time in response to different selection pressures. Using a phylogenomic approach, we searched for expanded endopeptidase families in the S. mansoni predicted proteome with the aim of contributing to the knowledge of such enzymes as potential therapeutic targets. We found three endopeptidase families that comprise leishmanolysins (metallopeptidase M8 family), cercarial elastases (serine peptidase S1 family) and cathepsin D proteins (aspartic peptidase A1 family). Our results suggest that the Schistosoma members of these families originated from successive gene duplication events in the parasite lineage after its diversification from other metazoans. Overall, critical residues are conserved among the duplicated genes/proteins. Furthermore, each protein family displays a distinct evolutionary history. Altogether, this work provides an evolutionary view of three S. mansoni peptidase families, which allows for a deeper understanding of the genomic complexity and lineage-specific adaptations potentially related to the parasitic lifestyle.

Twitch potentia induced by two different modalities of neuromuscular electrical stimulation: implications for motor unit recruitment.

INTRODUCTION: We tested the hypothesis that twitch potentiation would be greater following conventional (CONV) neuromuscular electrical stimulation (50-µs pulse width and 25-Hz frequency) compared with wide-pulse high-frequency (WPHF) neuromuscular electrical stimulation (1-ms, 100-Hz) and voluntary (VOL) contractions, because of specificities in motor unit recruitment (random in CONV vs. random and orderly in WPHF vs. orderly in VOL). METHODS: A single twitch was evoked by means of tibial nerve stimulation before and 2 s after CONV, WPHF, and VOL conditioning contractions of the plantar flexors (intensity: 10% maximal voluntary contraction; duration: 10 s) in 13 young healthy subjects. RESULTS: Peak twitch increased (P<0.05) after CONV (+4.5±4.0%) and WPHF (+3.3±5.9%), with no difference between the 2 modalities, whereas no changes were observed after VOL (+0.8±2.6%). CONCLUSIONS: Our results demonstrate that presumed differences in motor unit recruitment between WPHF and CONV do not seem to influence twitch potentiation results.

Diversity and microdistribution of black fly (Diptera: Simuliidae) assemblages in the tropical savanna streams of the Brazilian cerrado

We describe the abiotic factors affecting the distribution of black flies at a microhabitat scale, rather than at the regional scale usually present in the literature on the Neotropics. Black fly larvae were sampled from the Tocantins River and three tributaries, located in the Brazilian savanna (state of Tocantins, Brazil) during six bi-monthly sampling periods from October 2004-August 2005. At each sampling site, 15 random quadrats (30 x 30 cm) were sampled each period and for each quadrat were determined mean water velocity, predominant substrate type (rocks, riffle litter or riparian vegetation) and depth detrended correspondence analysis (DCA) was used to determine associations with current velocity, whereas correspondence analysis (CA) was used to estimate site specific current velocity associations. Canonical correspondence analysis (CCA) was used to identify general microhabitat associations. The CCA showed that most species had a trend towards riffle litter, except for Simulium nigrimanum associated with rocky substrate and Simulium cuasiexiguum associated with riparian vegetation. The DCA showed a well defined pattern of water velocity associations. The CA revealed that the species showed different speed associations from one site to another, suggesting different competitive pressures resulting in the occurrence of different realized niches.

Temporal variation of wing geometry in Aedes albopictus

Although native to the tropical and subtropical areas of Southeast Asia, Aedes albopictus is now found on five continents, primarily due to its great capacity to adapt to different environments. This species is considered a secondary vector of dengue virus in several countries. Wing geometric morphometrics is widely used to furnish morphological markers for the characterisation and identification of species of medical importance and for the assessment of population dynamics. In this work, we investigated the metric differentiation of the wings of Ae. albopictus samples collected over a four-year period (2007-2010) in São Paulo, Brazil. Wing size significantly decreased during this period for both sexes and the wing shape also changed over time, with the wing shapes of males showing greater differences after 2008 and those of females differing more after 2009. Given that the wings play sex-specific roles, these findings suggest that the males and females could be affected by differential evolutionary pressures. Consistent with this hypothesis, a sexually dimorphic pattern was detected and quantified: the females were larger than the males (with respect to the mean) and had a distinct wing shape, regardless of allometric effects. In conclusion, wing alterations, particularly those involving shape, are a sensitive indicator of microevolutionary processes in this species.