RESUMO
Designated under the name of chromoanagenesis, the phenomena of chromothripsis, chromanasynthesis and chromoplexy constitute new types of complex rearrangements, including many genomic alterations localized on a few chromosomal regions, and whose discovery over the last decade has changed our perception about the formation of chromosomal abnormalities and their etiology. Although exhibiting specific features, these new catastrophic mechanisms generally occur within a single cell cycle and their emergence is closely linked to genomic instability. Various non-exclusive exogenous or cellular mechanisms capable of generating chromoanagenesis have been evoked. However, recent experimental data shed light on 2 major processes, which following a defect in the mitotic segregation of chromosomes, can generate a cascade of cellular events leading to chromoanagenesis. These mechanisms are the formation of micronuclei integrating isolated chromosomal material, and the occurrence of chromatin bridges around chromosomal material resulting from telomeric fusions. In both cases, the cellular and molecular mechanisms of fragmentation, repair and transmission of damaged chromosomal material are consistent with the features of chromoanagenesis-related complex chromosomal rearrangements. In this review, we introduce each type of chromoanagenesis, and describe the experimental models that have allowed to validate the existence of chromoanagenesis events and to better understand their cellular mechanisms of formation and transmission, as well as their impact on the stability and the plasticity of the genome.
Assuntos
Cromotripsia , Aberrações Cromossômicas , Rearranjo Gênico , Instabilidade Genômica/genética , Genômica , Humanos , Telômero/genéticaRESUMO
Tyrosine kinase inhibitor (TKI) discontinuation in chronic phase chronic myeloid leukemia (CML) patients has been examined in a real-life setting in the east occitania region of France. We have collected sex, age, prognostic scores, pre-TKI treatment, TKI length and response, relapse data from patients who had stopped TKI in prolonged complete molecular remission (CMR), and analyzed relapse risk factors. Sixty consecutive patients were included from january 2010 to december 2016. Sixteen received pre-TKI treatment. Fifty-three received a first-generation TKI, and seven had a second-generation TKI in first-line therapy. The median TKI time to achieve CMR was 20.5 months [5-137]. The median TKI length before discontinuation treatment was 73 months [12-158]. Twenty-two patients (37%) relapsed with a median time to relapse of 6 months [3-27]. An intermediate or high Sokal score was the only relapse risk factor (HR = 3.32, p < 0.05) associated with relapse after TKI discontinuation. TKI discontinuation was possible without relapse for half of the patients in chronic phase CML. In a real-life cohort, a high-risk Sokal score at diagnosis appears to be an adverse prognosis feature for TKI discontinuation.
Assuntos
Leucemia Mielogênica Crônica BCR-ABL Positiva , Leucemia Mieloide de Fase Crônica , Humanos , Leucemia Mielogênica Crônica BCR-ABL Positiva/induzido quimicamente , Leucemia Mielogênica Crônica BCR-ABL Positiva/tratamento farmacológico , Leucemia Mielogênica Crônica BCR-ABL Positiva/epidemiologia , Inibidores de Proteínas Quinases/efeitos adversos , Recidiva , Estudos RetrospectivosRESUMO
Evolution should favour plasticity in dispersal decisions in response to spatial heterogeneity in social and environmental contexts. Sex differences in individual optimization of dispersal decisions are poorly documented in mammals, because species where both sexes commonly disperse are rare. To elucidate the sex-specific drivers governing dispersal, we investigated sex differences in condition dependence in the propensity and distance of natal dispersal in one such species, the roe deer, using fine-scale monitoring of 146 GPS-collared juveniles in an intensively monitored population in southwest France. Dispersal propensity increased with body mass in males such that 36% of light individuals dispersed, whereas 62% of heavy individuals did so, but there was no evidence for condition dependence in dispersal propensity among females. By contrast, dispersal distance increased with body mass at a similar rate in both sexes such that heavy dispersers travelled around twice as far as light dispersers. Sex differences in the strength of condition-dependent dispersal may result from different selection pressures acting on the behaviour of males and females. We suggest that females disperse prior to habitat saturation being reached, likely in relation to the risk of inbreeding. By contrast, natal dispersal in males is likely governed by competitive exclusion through male-male competition for breeding opportunities in this strongly territorial mammal. Our study is, to our knowledge, a first demonstration that condition dependence in dispersal propensity and dispersal distance may be decoupled, indicating contrasting selection pressures drive the behavioural decisions of whether or not to leave the natal range, and where to settle.
Assuntos
Cervos , Herbivoria , Animais , Feminino , França , Humanos , Endogamia , Masculino , Caracteres SexuaisRESUMO
Nowadays there are approximately 80 Anglophone journals that deal primarily with disaster risk reduction (DRR) and allied fields. This large array signals a sustained, if uneven, growth in DRR scholarship but also competition between the offerings of different publishers and institutions. The purpose of this article is first to summarise the development of academic publishing on DRR from its early beginnings to the present day. The paper then evaluates the current state of publishing in this field and discusses possible future trends. Next, it identifies some possible opportunities, challenges, expectations, and commitments for journal editors both within DRR and academia more broadly, including those that refer to changes in the use of terminology, the relentless increase in the number of papers submitted, the expansion and dangers of predatory journals, different peer review models, open access versus paywalls, citations and bibliography metrics, academic social networks, and copyright and distribution issues.
Assuntos
Desastres , Editoração/tendências , Comportamento de Redução do Risco , HumanosAssuntos
Vítimas de Desastres , Desastres , Pesquisa , Códigos de Ética , Planejamento em Desastres , HumanosRESUMO
The induced membrane technique is now well accepted for reconstruction of segmental bone defect. On the other hand, some cases of aseptic non-union are unsuccessfully treated by several surgical attempts for obtaining bone healing. The two stages wrapping induced membrane technique was developed initially for treating atrophic and recalcitrant aseptic non union without bone loss. At the first stage, the site of non-union was firmly fixed and tiles of cement were placed close to the bone on two or three aspects of the bone. At the second stage, after removing the spacers, the induced cavities were filled with cancellous bone autograft. In the two reported cases bone healing was acquired in 4 months. One case was a recalcitrant atrophic non-union of the humeral shaft, the other case concerned the enhancement of an insufficient segmental reconstruction of the femur. The follow up were respectively 3 years and 2 years without complication. The membrane induced by the cement tiles prevents the bone graft resorption and improves the osteogenicity through its biological properties.
Assuntos
Transplante Ósseo , Consolidação da Fratura , Humanos , Transplante Autólogo , Resultado do TratamentoRESUMO
According to the principle of allocation, trade-offs are inevitable when resources allocated to one biological function are no longer available for other functions. Growth, and to a lesser extent, immunity are energetically costly functions that may compete with allocation to reproductive success and survival. However, whether high allocation to growth impairs immune system development during the growing period or immune system performance during adulthood is currently unknown in wild mammals. Using three roe deer (Capreolus capreolus) populations experiencing contrasting environmental conditions, we tested for potential costs of growth on immune phenotype over both the short-term (during growth), and the long-term (during adulthood) over the course of an individuals' life. We investigated potential costs on a set of 12 immune traits that reflect both innate and adaptive responses, and compared them between sexes and populations. Although fast growth tended to be associated with low levels of some humoral traits (globulins) during the growing period and some cellular immune traits (i.e. eosinophil and neutrophil counts) during adulthood, evidence for a trade-off between growth and other immune components was limited. Unexpectedly, no detectable growth costs on immunity were found in females from the population experiencing the least favourable environment. We discuss our findings in the light of the complex interplay between resource allocation strategies among reproduction, maintenance and immunity, in relation to local environmental conditions experienced by roe deer.
Assuntos
Cervos , Herbivoria , Adulto , Animais , Feminino , Fenótipo , ReproduçãoRESUMO
Disaster studies is faced with a fascinating anomaly: frequently it claims to be critical and innovative, as suggested by the so-called vulnerability paradigm that emerged more than 40 years ago, yet often it is perpetuating some of the core and problematic tenets of the hazard paradigm that we were asked to challenge initially. This paper interrogates why such an anomaly persists. In so doing, it employs Antonio Gramsci's concept of hegemony to unpack why disaster studies is still dominated by Western epistemologies and scholars that perpetuate an orientalist view of disasters. Ultimately, it suggests a research agenda for the 40 years to come, which builds on the importance of local researchers analysing local disasters using local epistemologies, especially in the non-Western world. Such subaltern disaster studies are to be fuelled by increasing consciousness of the need to resist the hegemony of Western scholarship and to relocate disaster studies within the realm of its original political agenda.
Assuntos
Desastres , Pesquisa/tendências , HumanosRESUMO
BACKGROUND: Understanding the genetic and environmental mechanisms governing variation in morphology or phenology in wild populations is currently an important challenge. While there is a general consensus that selection is stronger under stressful conditions, it remains unclear whether the evolutionary potential of traits should increase or decrease with increasingly stressful conditions. Here, we investigate how contrasting environmental conditions during growth may affect the maternal and genetic components of body mass in roe deer, the most abundant and widespread wild ungulate in Western Europe. Body mass is a key life history trait that strongly influences both survival and reproductive performance in large herbivores. We used pedigrees and animal models to determine the variance components of juvenile and adult winter body mass in two populations experiencing contrasting early-life conditions. RESULTS: Our analyses showed that roe deer at Chizé, where habitat was poor and unpredictable, exhibited very low genetic variance in juvenile body mass. Instead, variance in mass was mainly driven by among-cohort differences in early-life conditions and maternal environment. In contrast, roe deer at Bogesund, where resource availability during the critical period of fawn rearing was higher, displayed a substantial level of genetic variance in body mass. We discuss the potential role of past demography and viability selection on fawn body mass on the erosion of genetic variance in the poor habitat. CONCLUSIONS: Our study highlights the importance of accounting for both spatial (i.e. between-population variation) and temporal (i.e. cohort variation) heterogeneity in environmental conditions, especially in early life, to understand the potential for adaptive responses of wild populations to selection.
Assuntos
Peso Corporal/genética , Cervos/anatomia & histologia , Cervos/genética , Genética Populacional , Animais , Demografia , Ecossistema , Europa (Continente) , Feminino , Variação Genética , Masculino , Reprodução/fisiologia , Estações do AnoRESUMO
The perforators of the fibular artery provide a well vascularised supra fascial network which allows to raise a proximally or a distally based island fascio cutaneous flap with an adipo-fascial pedicle. We present a short series of five cases of this flap for coverage of soft tissue defects involving the region of the knee, the distal third of the leg and the lateral aspect of the heel. All flaps healed entirely without venous congestion. The advantages of the fascio cutaneous fibular island flap are the supine operative position, the preservation of the sural nerve and the lesser saphenous vein and a pivot point which can be located at the middle third of the leg. According to our experience, the fascio cutaneous fibular island flap is especially indicated for repairing defects of the distal leg.
Assuntos
Fíbula/irrigação sanguínea , Extremidade Inferior/cirurgia , Retalhos Cirúrgicos/irrigação sanguínea , Humanos , Úlcera da Perna/cirurgia , Necrose/cirurgia , Osteíte/cirurgia , Pele/patologiaRESUMO
How selection pressures acting within species interact with developmental constraints to shape macro-evolutionary patterns of species divergence is still poorly understood. In particular, whether or not sexual selection affects evolutionary allometry, the increase in trait size with body size across species, of secondary sexual characters, remains largely unknown. In this context, bovid horn size is an especially relevant trait to study because horns are present in both sexes, but the intensity of sexual selection acting on them is expected to vary both among species and between sexes. Using a unique data set of sex-specific horn size and body mass including 91 species of bovids, we compared the evolutionary allometry between horn size and body mass between sexes while accounting for both the intensity of sexual selection and phylogenetic relationship among species. We found a nonlinear evolutionary allometry where the allometric slope decreased with increasing species body mass. This pattern, much more pronounced in males than in females, suggests either that horn size is limited by some constraints in the largest bovids or is no longer the direct target of sexual selection in very large species.
Assuntos
Evolução Biológica , Bovinos/anatomia & histologia , Bovinos/classificação , Cornos/anatomia & histologia , Animais , Tamanho Corporal , Feminino , Masculino , Filogenia , Seleção Genética , Caracteres SexuaisRESUMO
Consideration of gender in the disaster sphere has centred almost exclusively on the vulnerability and capacities of women. This trend stems from a polarised Western understanding of gender as a binary concept of man-woman. Such an approach also mirrors the dominant framing of disasters and disaster risk reduction (DRR), emphasising Western standards and practices to the detriment of local, non-Western identities and experiences. This paper argues that the man-woman dichotomy is an insufficient construct with which to address the gendered dimensions of a disaster as it fails to capture the realities of diverse gender minorities in non-Western contexts. The paper presents case studies from the Philippines, Indonesia, and Samoa, where gender minorities display specific patterns of vulnerability associated with their marginal positions in society, yet, importantly, also possess a wide array of endogenous capacities. Recognition of these differences, needs, skills, and unique resources is essential to moving towards inclusive and gender-sensitive DRR.
Assuntos
Desastres , Identidade de Gênero , Grupos Minoritários , Populações Vulneráveis , Feminino , Humanos , Indonésia , Masculino , Filipinas , Comportamento de Redução do Risco , SamoaRESUMO
A central tenet of evolutionary biology states that life-history traits are linked via trade-offs, as classically exemplified by the van Noordwijk and de Jong model. This model, however, assumes that the relative resource allocation to a biological function varies independently of the total resource acquisition. Based on current empirical evidence, we first explored the dependency between the total resource acquisition and the relative resource allocation to reproduction and showed that such dependency is the rule rather than the exception. We then derived the expression of the covariance between traits when the assumption of independence is relaxed and used simulations to quantify the importance of such dependency on the detection of trade-offs between current reproduction and future survival. We found that the dependency between the total energy acquisition and the relative allocation to reproduction can influence the probability to detect trade-offs between survival and reproduction. As a general rule, a negative dependency between the total energy acquisition and the relative allocation to reproduction should lead to a higher probability of detecting a trade-off in species with a fast pace of life, whereas a positive dependency should lead to a higher probability of detecting a trade-off in species with a slow pace of life. In addition to confirming the importance of resource variation to reveal trade-offs, our finding demonstrates that the covariance between resource allocation and resource acquisition is generally not null and also plays a fundamental role in the detection of trade-offs.
Assuntos
Evolução Biológica , Reprodução , FenótipoRESUMO
This short communication provides insights into water, sanitation and hygiene (WASH) for homeless people through a scoping study conducted in Dhaka, Bangladesh. It investigates homeless access to WASH through the lens of a rights-based approach. It demonstrates that homeless people's denial of their right to WASH reflects their marginal position in society and an unequal distribution of power and opportunities. The study ultimately suggests a rights-based approach to work toward dealing with the root causes of discrimination and marginalisation rather than just the symptoms. For the homeless, who not only lack substantive rights, but also the means through which to claim their rights, an integrated rights-based approach to WASH offers the possibility for social inclusion and significant improvements in their life conditions. Given the unique deprivation of homelessness it is argued that in addressing the lack of access to adequate WASH for homeless people the immediate goal should be the fulfilment and protection of the right to adequate shelter.
Assuntos
Higiene , Pessoas Mal Alojadas , Saneamento/métodos , Abastecimento de Água , Bangladesh , Cidades , Humanos , Higiene/normas , Abastecimento de Água/estatística & dados numéricosRESUMO
Liver regeneration after injury occurs in many mammals. Rat liver regenerates after partial hepatectomy over a period of 2 weeks while human liver regeneration takes several months. Notwithstanding this enormous difference in time-scales, with new data from five human live liver transplant donors, we show that a mathematical model of rat liver regeneration can be transferred to human, with all biochemical interactions and signaling unchanged. Only six phenomenological parameters need change, and three of these parameter changes are rescalings of rate constants by the ratio of human lifespan to rat lifespan. Data from three donor subjects with approximately equal resections were used to fit the three parameters and the data from the other two donor subjects was used to independently verify the fit.
Assuntos
Hepatócitos/fisiologia , Regeneração Hepática/fisiologia , Fígado/fisiologia , Modelos Biológicos , Hepatócitos/citologia , Humanos , Fatores de Tempo , Doadores de TecidosRESUMO
When individuals disperse, they modify the physical and social composition of their reproductive environment, potentially impacting their fitness. The choice an individual makes between dispersal and philopatry is thus critical, hence a better understanding of the mechanisms involved in the decision to leave the natal area is crucial. We explored how combinations of behavioural (exploration, mobility, activity and stress response) and morphological (body mass) traits measured prior to dispersal were linked to the subsequent dispersal decision in 77 roe deer Capreolus capreolus fawns. Using an unusually detailed multi-trait approach, we identified two independent behavioural continuums related to dispersal. First, a continuum of energetic expenditure contrasted individuals of low mobility, low variability in head activity and low body temperature with those that displayed opposite traits. Second, a continuum of neophobia contrasted individuals that explored more prior to dispersal and were more tolerant of capture with those that displayed opposite traits. While accounting for possible confounding effects of condition-dependence (body mass), we showed that future dispersers were less neophobic and had higher energetic budgets than future philopatric individuals, providing strong support for a dispersal syndrome in this species.
Assuntos
Distribuição Animal , Peso Corporal , Cervos/fisiologia , Animais , Temperatura Corporal , Ecossistema , Feminino , França , Sistemas de Informação Geográfica , Masculino , Movimento , FenótipoRESUMO
Increasing evidence of senescence has been reported from long-term studies of wild populations. However, most studies have focused on life-history traits like survival, reproduction or body mass, generally from a single intensively monitored population. However, variation in the intensity of senescence across populations, and to a lesser extent between sexes, is still poorly understood. In addition, the pattern of age-specific changes in haematological parameters remains virtually unknown to date for any population of vertebrate living in the wild. Using repeated blood samples collected from known-aged (2-15 years of age) roe deer (Capreolus capreolus) from two populations facing highly different environmental conditions, we filled the gap. In particular, we investigated age-specific changes in haematocrit, albumin and creatinine. We reported clear evidence of senescence in all haematological parameters. Moreover, senescence patterns differed between sexes and populations. The rate of senescence was higher in males than in females for haematocrit with no site difference. On the other hand, the rate of senescence in creatinine was higher at Trois Fontaines than at Chizé with no sex difference. Our findings provide a first demonstration of age-specific declines in haematological parameters in wild populations of large herbivores and show that the process of senescence in vertebrates is not restricted to body mass or fitness components. We also demonstrate that the senescence pattern of haematological parameters is context dependent and varies both between sexes and according to environmental conditions.
Assuntos
Envelhecimento/fisiologia , Animais Selvagens/fisiologia , Cervos/fisiologia , Meio Ambiente , Fatores Etários , Envelhecimento/sangue , Animais , Animais Selvagens/sangue , Creatinina/sangue , Cervos/sangue , Feminino , França , Geografia , Hematócrito , Masculino , Modelos Biológicos , Fatores SexuaisRESUMO
Allometric relationships between sexually selected traits and body size have been extensively studied in recent decades. While sexually selected traits generally display positive allometry, a few recent reports have suggested that allometric relationships are not always linear. In male cervids, having both long antlers and large size provides benefits in terms of increased mating success. However, such attributes are costly to grow and maintain, and these costs might constrain antler length from increasing at the same rate as body mass in larger species if the quantity of energy that males can extract from their environment is limiting. We tested for possible nonlinearity in the relationship between antler size and body mass (on a log-log scale) among 31 cervids and found clear deviation from linearity in the allometry of antler length. Antler length increased linearly until a male body mass threshold at approximately 110 kg. Beyond this threshold, antler length did not change with increasing mass. We discuss this evidence of nonlinear allometry in the light of life-history theory and stress the importance of testing for nonlinearity when studying allometric relationships.
Assuntos
Chifres de Veado/anatomia & histologia , Tamanho Corporal , Cervos/anatomia & histologia , Cervos/fisiologia , Animais , Chifres de Veado/crescimento & desenvolvimento , Cervos/crescimento & desenvolvimento , Ingestão de Energia , Fenótipo , Caracteres Sexuais , Especificidade da EspécieRESUMO
The role of Campylobacter jejuni as the triggering agent of Guillain-Barré syndrome (GBS) has not been reassessed since the end of the 1990s in France. We report that the number of C. jejuni-related GBS cases increased continuously between 1996 and 2007 in the Paris region (mean annual increment: 7%, P = 0·007).
Assuntos
Infecções por Campylobacter/complicações , Campylobacter jejuni/imunologia , Síndrome de Guillain-Barré/epidemiologia , Adulto , Idoso , Feminino , França , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Paris/epidemiologiaRESUMO
The paramyxean parasite Marteilia refringens infects several bivalve species including European flat oysters Ostrea edulis and Mediterranean mussels Mytilus galloprovincialis. Sequence polymorphism allowed definition of three parasite types 'M', 'O' and 'C' preferably detected in oysters, mussels and cockles respectively. Transmission of the infection from infected bivalves to copepods Paracartia grani could be experimentally achieved but assays from copepods to bivalves failed. In order to contribute to the elucidation of the M. refringens life cycle, the dynamics of the infection was investigated in O. edulis, M. galloprovincialis and zooplankton over one year in Diana lagoon, Corsica (France). Flat oysters appeared non-infected while mussels were infected part of the year, showing highest prevalence in summertime. The parasite was detected by PCR in zooplankton particularly after the peak of prevalence in mussels. Several zooplanktonic groups including copepods, Cladocera, Appendicularia, Chaetognatha and Polychaeta appeared PCR positive. However, only the copepod species Paracartia latisetosa showed positive signal by in situ hybridization. Small parasite cells were observed in gonadal tissues of female copepods demonstrating for the first time that a copepod species other than P. grani can be infected with M. refringens. Molecular characterization of the parasite infecting mussels and zooplankton allowed the distinguishing of three Marteilia types in the lagoon.