RESUMO
PURPOSE: Single large hepatocellular carcinoma >5cm (SLHCC) traditionally requires a major liver resection. Minor resections are often performed with the goal to reduce morbidity and mortality. Aim of the study was to establish if a major resection should be considered the best treatment for SLHCC or a more limited resection should be preferred. METHODS: A multicenter retrospective analysis of the HE.RC.O.LE.S. Group register was performed. All collected patients with surgically treated SLHCC were divided in 5 groups of treatment (major hepatectomy, sectorectomy, left lateral sectionectomy, segmentectomy, non-anatomical resection) and compared for baseline characteristics, short and long-term results. A propensity-score weighted analysis was performed. RESULTS: 535 patients were enrolled in the study. Major resection was associated with significantly increased major complications compared to left lateral sectionanectomy, segmentectomy and non-anatomical resection (all p<0.05) and borderline significant increased major complications compared to sectorectomy (p=0.08). Left lateral sectionectomy showed better overall survival compared to major resection (p=0.02), while other groups of treatment resulted similar to major hepatectomy group for the same item. Absence of oncological benefit after major resection and similar outcomes among the 5 groups of treatment was confirmed even in the sub-population excluding patients with macrovascular invasion. CONCLUSION: Major resection was associated to increased major post-operative morbidity without long-term survival benefit; when technically feasible and oncologically adequate, minor resections should be preferred for the surgical treatment of SLHCC.
Assuntos
Carcinoma Hepatocelular , Hepatectomia , Neoplasias Hepáticas , Pontuação de Propensão , Humanos , Hepatectomia/métodos , Carcinoma Hepatocelular/cirurgia , Carcinoma Hepatocelular/patologia , Carcinoma Hepatocelular/mortalidade , Neoplasias Hepáticas/cirurgia , Neoplasias Hepáticas/patologia , Neoplasias Hepáticas/mortalidade , Masculino , Feminino , Estudos Retrospectivos , Pessoa de Meia-Idade , Idoso , Complicações Pós-Operatórias/etiologia , Resultado do Tratamento , Taxa de Sobrevida , AdultoRESUMO
The genetic architecture of speciation, i.e., how intrinsic genomic incompatibilities promote reproductive isolation (RI) between diverging lineages, is one of the best-kept secrets of evolution. To directly assess whether incompatibilities arise in a limited set of large-effect speciation genes, or in a multitude of loci, we examined the geographic and genomic landscapes of introgression across the hybrid zones of 41 pairs of frog and toad lineages in the Western Palearctic region. As the divergence between lineages increases, phylogeographic transitions progressively become narrower, and larger parts of the genome resist introgression. This suggests that anuran speciation proceeds through a gradual accumulation of multiple barrier loci scattered across the genome, which ultimately deplete hybrid fitness by intrinsic postzygotic isolation, with behavioral isolation being achieved only at later stages. Moreover, these loci were disproportionately sex linked in one group (Hyla) but not in others (Rana and Bufotes), implying that large X-effects are not necessarily a rule of speciation with undifferentiated sex chromosomes. The highly polygenic nature of RI and the lack of hemizygous X/Z chromosomes could explain why the speciation clock ticks slower in amphibians compared to other vertebrates. The clock-like dynamics of speciation combined with the analytical focus on hybrid zones offer perspectives for more standardized practices of species delimitation.
Assuntos
Anuros/genética , Loci Gênicos , Especiação Genética , Animais , Genoma , Isolamento ReprodutivoRESUMO
OBJECTIVE: To evaluate the effect of a liver transplantation (LT) program on the outcomes of resectable hepatocellular carcinoma (HCC). BACKGROUND: Surgical treatment of HCC includes both hepatic resection (HR) and LT. However, the presence of cirrhosis and the possibility of recurrence make the management of this disease complex and probably different according to the presence of a LT program. METHODS: Patients undergoing HR for HCC between January 2005 and December 2019 were identified from a national database of HCC. The main study outcomes were major surgical complications according to the Comprehensive Complication Index, posthepatectomy liver failure (PHLF), 90-day mortality, overall survival, and disease-free survival. Secondary outcomes were salvage liver transplantation (SLT) and postrecurrence survival. RESULTS: A total of 3202 patients were included from 25 hospitals over the study period. Three of 25 (12%) had an LT program. The presence of an LT program within a center was associated with a reduced probability of PHLF (odds ratio=0.38) but not with overall survival and disease-free survival. There was an increased probability of SLT when HR was performed in a transplant hospital (odds ratio=12.05). Among transplant-eligible patients, those who underwent LT had a significantly longer postrecurrence survival. CONCLUSIONS: This study showed that the presence of a LT program was associated with decreased PHLF rates and an increased probability to receive SLT in case of recurrence.
Assuntos
Carcinoma Hepatocelular , Falência Hepática , Neoplasias Hepáticas , Transplante de Fígado , Humanos , Carcinoma Hepatocelular/cirurgia , Cirrose Hepática/complicações , Falência Hepática/complicações , Recidiva Local de Neoplasia/epidemiologia , Estudos RetrospectivosRESUMO
BACKGROUND: We aimed to evaluate, in a large Western cohort, perioperative and long-term oncological outcomes of salvage hepatectomy (SH) for recurrent hepatocellular carcinoma (rHCC) after primary hepatectomy (PH) or locoregional treatments. METHODS: Data were collected from the Hepatocarcinoma Recurrence on the Liver Study Group (He.RC.O.Le.S.) Italian Registry. After 1:1 propensity score-matched analysis (PSM), two groups were compared: the PH group (patients submitted to resection for a first HCC) and the SH group (patients resected for intrahepatic rHCC after previous HCC-related treatments). RESULTS: 2689 patients were enrolled. PH included 2339 patients, SH 350. After PSM, 263 patients were selected in each group with major resected nodule median size, intraoperative blood loss and minimally invasive approach significantly lower in the SH group. Long-term outcomes were compared, with no difference in OS and DFS. Univariate and multivariate analyses revealed only microvascular invasion as an independent prognostic factor for OS. CONCLUSION: SH proved to be equivalent to PH in terms of safety, feasibility and long-term outcomes, consistent with data gathered from East Asia. In the awaiting of reliable treatment-allocating algorithms for rHCC, SH appears to be a suitable alternative in patients fit for surgery, regardless of the previous therapeutic modality implemented.
Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , Carcinoma Hepatocelular/patologia , Hepatectomia/efeitos adversos , Humanos , Neoplasias Hepáticas/patologia , Recidiva Local de Neoplasia/patologia , Pontuação de Propensão , Estudos Retrospectivos , Resultado do TratamentoRESUMO
BACKGROUND: Benchmark analysis for open liver surgery for cirrhotic patients with hepatocellular carcinoma (HCC) is still undefined. METHODS: Patients were identified from the Italian national registry HE.RC.O.LE.S. The Achievable Benchmark of Care (ABC) method was employed to identify the benchmarks. The outcomes assessed were the rate of complications, major comorbidities, post-operative ascites (POA), post-hepatectomy liver failure (PHLF), 90-day mortality. Benchmarking was stratified for surgical complexity (CP1, CP2 and CP3). RESULTS: A total of 978 of 2698 patients fulfilled the inclusion criteria. 431 (44.1%) patients were treated with CP1 procedures, 239 (24.4%) with CP2 and 308 (31.5%) with CP3 procedures. Patients submitted to CP1 had a worse underlying liver function, while the tumor burden was more severe in CP3 cases. The ABC for complications (13.1%, 19.2% and 28.1% for CP1, CP2 and CP3 respectively), major complications (7.6%, 11.1%, 12.5%) and 90-day mortality (0%, 3.3%, 3.6%) increased with the surgical difficulty, but not POA (4.4%, 3.3% and 2.6% respectively) and PHLF (0% for all groups). CONCLUSION: We propose benchmarks for open liver resections in HCC cirrhotic patients, stratified for surgical complexity. The difference between the benchmark values and the results obtained during everyday practice reflects the room for potential growth, with the aim to encourage constant improvement among liver surgeons.
Assuntos
Carcinoma Hepatocelular , Falência Hepática , Neoplasias Hepáticas , Benchmarking , Hepatectomia/efeitos adversos , Hepatectomia/métodos , Humanos , Cirrose Hepática/complicações , Cirrose Hepática/patologia , Cirrose Hepática/cirurgia , Falência Hepática/etiologia , Neoplasias Hepáticas/complicações , Neoplasias Hepáticas/cirurgia , Complicações Pós-Operatórias , Estudos RetrospectivosRESUMO
A few prospective trials in HIV-positive patients with Burkitt lymphoma (BL) or high-grade B-cell lymphoma (HGBL) have been reported. Investigated therapies have shown good efficacy but relevant safety problems, with high rates of interruptions, severe mucositis, septic complications, and fungal infections. Here, we report the results of a multicentre phase II trial addressing a new dose-dense, short-term therapy aimed at maintaining efficacy and improving tolerability. The experimental programme included a 36-day polychemotherapy induction followed by high-dose cytarabine-based consolidation and response-tailored BEAM (carmustine, etoposide, cyatarabine, and melphalan)- conditioned autologous stem cell transplantation (ASCT). This therapy would be considered active if ≥11 complete remissions (CR) after induction (primary endpoint) were recorded among 20 assessable patients. HIV-positive adults (median age 42, range 26-58; 16 males) with untreated BL (n = 16), HGBL (n = 3) or double-hit lymphoma (n = 1) were enrolled. All patients had high-risk features, with meningeal and bone marrow infiltration in five and nine patients respectively. The experimental programme was safe and active in a multicentre setting, with only two episodes of grade 4 non-haematological toxicity (hepatotoxicity and mucositis), and no cases of systemic fungal infections; two patients died of toxicity (bacterial infections). Response after induction (median duration: 47 days; interquartile range 41-54), was complete in 13 patients and partial in five [overall response rate = 90%; 95% confidence interval (CI) = 77-100]. All responders received consolidation, and five required autologous stem cell transplant. At a median follow-up of 55 (41-89) months, 14 patients are relapse-free and 15 are alive, with a five-year progression-free survival and an overall survival of 70% (95% CI = 60-80%) and 75% (95% CI = 66-84) respectively. No patient with cerebrospinal fluid (CSF)/meningeal lymphoma experienced central nervous system recurrence. With respect to previously reported regimens, this programme was delivered in a shorter period, and achieved the main goal of maintaining efficacy and improving tolerability.
Assuntos
Síndrome da Imunodeficiência Adquirida/complicações , Síndrome da Imunodeficiência Adquirida/terapia , Antimetabólitos Antineoplásicos/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Linfoma de Burkitt/terapia , Citarabina/uso terapêutico , Linfoma de Células B/terapia , Adulto , Antimetabólitos Antineoplásicos/administração & dosagem , Antimetabólitos Antineoplásicos/efeitos adversos , Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Antivirais/administração & dosagem , Antivirais/efeitos adversos , Antivirais/uso terapêutico , Linfoma de Burkitt/complicações , Carmustina/administração & dosagem , Carmustina/efeitos adversos , Carmustina/uso terapêutico , Citarabina/administração & dosagem , Citarabina/efeitos adversos , Etoposídeo/administração & dosagem , Etoposídeo/efeitos adversos , Etoposídeo/uso terapêutico , Feminino , Infecções por HIV/complicações , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Humanos , Linfoma de Células B/complicações , Masculino , Melfalan/administração & dosagem , Melfalan/efeitos adversos , Melfalan/uso terapêutico , Pessoa de Meia-Idade , Transplante Autólogo/efeitos adversosRESUMO
BACKGROUND AND AIM: Viral pneumonia is the most relevant clinical presentation of COVID-19 which may lead to severe acute respiratory syndrome and even death. Eosinopenia was often noticed in patients with COVID-19 pneumonia, but its role is poorly investigated. The aim of the present study was to investigate the characteristics and clinical outcomes of patients with COVID-19 pneumonia and eosinopenia. METHODS: We revised the records of consecutive patients with COVID-19 pneumonia admitted to our ER-COVID-19 area in order to compare clinical characteristics and outcomes of patients with and without eosinopenia. We considered the following clinical outcomes: 4-weeks survival; need for intensive respiratory support; and hospital discharge. RESULTS: Out of first 107 consecutive patients with pneumonia and a positive COVID-19 nasopharyngeal swab, 75 patients showed undetectable eosinophil count (absolute eosinopenia). At 4 weeks, 38 patients (38.4%) had required intensive respiratory treatment, 25 (23.4%) deceased and 42 (39.2%) were discharged. Compared with patients without absolute eosinopenia, patients with absolute eosinopenia showed higher need of intensive respiratory treatment (49.3% vs 13.3%, P < .001), higher mortality (30.6% vs 6.2%, P .006) and lower rate of hospital discharge (28% vs 65.6%, P < .001). Binary logistic regression analyses including neutrophil, lymphocyte, eosinophil, basophil and monocyte counts showed that absolute eosinopenia was an independent factor associated with 4-weeks mortality, need for intensive respiratory support and hospital discharge. CONCLUSIONS: Absolute eosinopenia is associated with clinical outcomes in patients with COVID-19 pneumonia and might be used as a marker to discriminate patients with unfavourable prognosis.
Assuntos
COVID-19 , Pneumonia Viral , Eosinófilos , Humanos , Contagem de Leucócitos , SARS-CoV-2RESUMO
INTRODUCTION: Retroperitoneal soft tissue sarcomas (RPSs) are mesenchymal neoplasms. The prevalence of protein energetic malnutrition (PEM) and its impact in RPS patients who were candidates for surgery is unknown. MATERIALS AND METHODS: A prospective feasibility study enrolled 35 patients with primary RPS who were candidates for extended multivisceral resection. PEM was screened at enrollment. Preoperative high protein ß-hydroxy-ß-methyl butyrate oral nutritional support (ONS) was provided according to the degree of PEM. After surgery, nutritional support followed standard practice, targeting at least 1 g/kg/day protein and 20 kcal/kg/day caloric intake within the third postoperative day (POD). PEM was re-evaluated before surgery on POD 10, and at 4 and 12 months after surgery. Primary outcomes were the patient's compliance to preoperative ONS and the physician's compliance to postoperative nutritional targets. RESULTS: PEM was documented in 46% of patients at baseline; ONS met a 91% adherence (overall well tolerated). After ONS, PEM reduced to 38% (p = 0.45). The postoperative caloric target was reached on day 4.1 (standard error ± 2.7), with a protocol adherence rate of 52%. On POD 10, 91% of patients experienced PEM, the worsening of which was greater after resection of four or more organs (p = 0.06). At 4 and 12 months after surgery, almost all patients had fully recovered. A significant correlation between PEM at surgery and postoperative complications was found (p = 0.04). CONCLUSIONS: Relevant PEM prevalence in RPS is documented for the first time. PEM correlates with greater morbidity. In this setting, preoperative ONS was feasible and well-tolerated. Disease-related factors for PEM and the ideal perioperative caloric target in the context of extended multivisceral resection need to be further investigated. Nutritional support should be included in enhanced recovery after surgery programs for RPS. TRIAL REGISTRY: ClinicalTrials.gov identifier: NCT03877588.
Assuntos
Suplementos Nutricionais , Assistência Perioperatória , Desnutrição Proteico-Calórica/terapia , Neoplasias Retroperitoneais/cirurgia , Sarcoma/cirurgia , Adulto , Idoso , Estudos de Viabilidade , Feminino , Humanos , Itália , Masculino , Pessoa de Meia-Idade , Avaliação Nutricional , Estado Nutricional , Apoio Nutricional , Cooperação do Paciente , Estudos Prospectivos , Desnutrição Proteico-Calórica/diagnóstico , Valeratos/administração & dosagemRESUMO
Molecular ecologists often rely on phylogenetic evidence for assessing the species-level systematics of newly discovered lineages. Alternatively, the extent of introgression at phylogeographic transitions can provide a more direct test to assign candidate taxa into subspecies or species categories. Here, we compared phylogenetic versus hybrid zone approaches of species delimitation in two groups of frogs from the Western Mediterranean region (Discoglossus and Pelodytes), by using genomic data (ddRAD). In both genera, coalescent analyses recovered almost all nominal taxa as "species". However, the least-diverged pairs D. g. galganoi/jeanneae and P. punctatus/hespericus admix over hundreds of kilometers, suggesting that they have not yet developed strong reproductive isolation and should be treated as conspecifics. In contrast, the comparatively older D. scovazzi/pictus and P. atlanticus/ibericus form narrow contact zones, consistent with species distinctiveness. Due to their complementarity, we recommend taxonomists to combine phylogenomics with hybrid zone analyses to scale the gray zone of speciation, i.e., the evolutionary window separating widely admixing lineages versus nascent reproductively isolated species. The radically different transitions documented here conform to the view that genetic incompatibilities accumulating with divergence generate a weak barrier to gene flow for long periods of time, until their effects multiply and the speciation process then advances rapidly. Given the variability of the gray zone among taxonomic groups, at least from our current abilities to measure it, we recommend to customize divergence thresholds within radiations to categorize lineages for which no direct test of speciation is possible.
Assuntos
Anuros , DNA Mitocondrial , Fluxo Gênico , Especiação Genética , Animais , Anuros/classificação , Anuros/genética , Região do Mediterrâneo , Filogenia , Análise de Sequência de DNARESUMO
BACKGROUND: Acute alcohol intoxication is universally considered a risk factor for traumatic brain injury (TBI), therefore an indication for head CT scan. There is no evidence in the literature for this attitude. Aim of this study is to assess the need for head CT scan in acutely alcohol-intoxicated subjects with mTBI and the role of Glasgow coma scale (GCS) score in this kind of patients. METHODS: We retrospectively analyzed all 3358 consecutive patients presenting to our department in Switzerland, with TBI as chief complaint between January 2014 and January 2018. RESULTS: Alcohol was a statistically significant factor for presentation with a GCS score lower than 15. As for bleedings in mild TBI patients, the results were somewhat contradictory with GCS 15 patients showing a higher percentage of hemorrhages than GCS 14 patients. By dividing alcohol-intoxicated subjects into groups per blood alcohol concentration, the higher was the alcohol level, the lower the GCS score. CONCLUSIONS: We can affirm that GCS score is underestimated in acutely intoxicated head trauma patients. In this kind of patient, alcohol is a confounding factor and mild TBI could be safely managed by watchful waiting.
Assuntos
Intoxicação Alcoólica , Concussão Encefálica , Intoxicação Alcoólica/epidemiologia , Concentração Alcoólica no Sangue , Escala de Coma de Glasgow , Humanos , Estudos Retrospectivos , SuíçaRESUMO
Disentangling the sources of variation in developing an effective immune response against pathogens is of major interest to immunoecology and evolutionary biology. To date, the link between immunocompetence and genetic variation at the major histocompatibility complex (MHC) has received little attention in wild animals, despite the key role of MHC genes in activating the adaptive immune system. Although several studies point to a link between MHC and immunocompetence, negative findings have also been reported. Such disparate findings suggest that limited statistical power might be affecting studies on this topic, owing to insufficient sample sizes and/or a generally small effect of MHC on the immunocompetence of wild vertebrates. To clarify this issue, we investigated the link between MHC variation and seven immunocompetence proxies in a large sample of barn owls and estimated the effect sizes and statistical power of this and published studies on this topic. We found that MHC poorly explained variation in immunocompetence of barn owls, with small-to-moderate associations between MHC and immunocompetence in owls (effect size: .1 ≥ r ≤ .3) similar to other vertebrates studied to date. Such small-to-moderate effects were largely associated with insufficient power, which was only sufficient (>0.8) to detect moderate-to-large effect sizes (r ≥ .3). Thus, studies linking MHC variation with immunocompetence in wild populations are underpowered to detect MHC effects, which are likely to be of generally small magnitude. Larger sample sizes (>200) will be required to achieve sufficient power in future studies aiming to robustly test for a link between MHC variation and immunocompetence.
Assuntos
Imunidade Adaptativa/genética , Evolução Molecular , Imunocompetência/genética , Complexo Principal de Histocompatibilidade/genética , Imunidade Adaptativa/imunologia , Alelos , Animais , Animais Selvagens , Variação Genética/genética , Variação Genética/imunologia , Complexo Principal de Histocompatibilidade/imunologia , Seleção Genética/genética , Estrigiformes/genética , Estrigiformes/imunologia , Vertebrados/genética , Vertebrados/imunologiaRESUMO
Comparative molecular studies emphasized a new biogeographic paradigm for the terrestrial fauna of North Africa, one of the last uncharted ecoregions of the Western Palearctic: two independent east-west divisions across the Maghreb. Through a comprehensive phylogeography, we assessed how this model suits the genetic diversification documented for the tree frog Hyla meridionalis sensu lato. Analyses of mtDNA variation and thousands of nuclear loci confirmed the old split (low-Pliocene) between Tunisian and Algerian populations. These lineages meet but barely admix in the eastern Maghreb (Algerian-Tunisian border), a sign of putatively advanced reproductive isolation. In the western Maghreb, we report a Pleistocene divergence between Moroccan and Algerian populations. Tree frogs thus follow both predictions: a double east-west break that gave rise to two suture zones characteristic of North-African phylogeography. Moreover, some intraspecific mtDNA variation is not mirrored by the nuclear data, emphasizing that evolutionary units should always be designated by multilocus approaches. Last but not least, we describe the Tunisian lineage as a new species endemic to Africa.
Assuntos
Anuros/genética , Especiação Genética , Variação Genética , África do Norte , Animais , Núcleo Celular/genética , DNA Mitocondrial/genética , Genética Populacional , Mitocôndrias/genética , Filogenia , Filogeografia , Análise de Componente PrincipalRESUMO
Genetic bottlenecks resulting from human-induced population declines make alarming symbols for the irreversible loss of our natural legacy worldwide. The grey wolf (Canis lupus) is an iconic example of extreme declines driven by anthropogenic factors. Here, we assessed the genetic signatures of 150 years of wolf persecution throughout the Western Palaearctic by high-throughput mitochondrial DNA sequencing of historical specimens in an unprecedented spatio-temporal framework. Despite Late Pleistocene bottlenecks, we show that historical genetic variation had remained high throughout Europe until the last several hundred years. In Western Europe, where wolves nearly got fully exterminated, diversity dramatically collapsed at the turn of the twentieth century and recolonization from few homogeneous relict populations induced drastic shifts of genetic composition. By contrast, little genetic displacement and steady levels of diversity were maintained in Eastern European regions, where human persecution had lesser effects on wolf demography. By comparing prehistoric, historic and modern patterns of genetic diversity, our study hence traces the timeframe and the active human role in the decline of the grey wolf, an emblematic yet controversial animal which symbolizes the complex relationship between human societies and nature conservation.
Assuntos
Variação Genética , Lobos/genética , Animais , DNA Mitocondrial , Europa (Continente) , Genética Populacional , Haplótipos , História do Século XIX , História do Século XX , Filogeografia/história , Dinâmica Populacional , Análise de Sequência de DNARESUMO
The owl family Tytonidae comprises two genera: Phodilus, limited to the forests of central Africa and South-East Asia, and the ubiquitous Tyto. The genus Tyto is majorly represented by the cosmopolitan Common Barn Owl group, with more than 30 subspecies worldwide. Discrete differences in body size and plumage colouration have led to the classification of this family into many species and subspecies, but the taxonomic status and phylogenetic relationships between taxa remain unclear, and in some groups controversial. Although several previous studies attempted to resolve this problem, they have been limited in their taxonomic and geographical coverage, or have relied on restricted molecular evidence and low sample sizes. Based on the most comprehensive sampling to date (16 out of 17 Tyto species, and one out of three Phodilus species), a multi-locus approach using seven mitochondrial and two nuclear markers, and taking advantage of field data and museum collections available worldwide, our main questions in this study were: (1) what are the phylogenetic relationships and classification status of the whole family; (2) when and where did the most important speciation events occur? We confirm that the Common Barn Owl, Tyto alba is divided into three main evolutionary units: the American Barn Owl, T. furcata; the Western Barn Owl, T. alba; and the Eastern Barn Owl, T. javanica, and suggest a Late Miocene (ca. 6â¯mya) Australasian and African origin of the group. Our results are supported by fossil age information, given that the most recent common ancestor between the Tytonidae genera Phodilus and Tyto was probably from the Oligocene (ca. 28â¯mya) of Australasia. We finally reveal six major Pleistocene radiations of Tyto, all resulting in wide-range distributions.
Assuntos
Fósseis , Filogenia , Estrigiformes/classificação , Animais , Australásia , Teorema de Bayes , Geografia , Funções Verossimilhança , Estrigiformes/genética , Fatores de TempoRESUMO
High rates of gene duplication and the highest levels of functional allelic diversity in vertebrate genomes are the main hallmarks of the major histocompatibility complex (MHC), a multigene family with a primordial role in pathogen recognition. The usual tight linkage among MHC gene duplicates may provide an opportunity for the evolution of haplotypes that associate functionally divergent alleles and thus grant the transmission of optimal levels of diversity to coming generations. Even though such associations may be a crucial component of disease resistance, this hypothesis has been given little attention in wild populations. Here, we leveraged pedigree data from a barn owl (Tyto alba) population to characterize MHC haplotype structure across two MHC class I (MHC-I) and two MHC class IIB (MHC-IIB) duplicates, in order to test the hypothesis that haplotypes' genetic diversity is higher than expected from randomly associated alleles. After showing that MHC loci are tightly linked within classes, we found limited evidence for shifts towards MHC haplotypes combining high diversity. Neither amino acid nor functional within-haplotype diversity were significantly higher than in random sets of haplotypes, regardless of MHC class. Our results therefore provide no evidence for selection towards high-diversity MHC haplotypes in barn owls. Rather, high rates of concerted evolution may constrain the evolution of high-diversity haplotypes at MHC-I, while, in contrast, for MHC-IIB, fixed differences among loci may provide barn owls with already optimized functional diversity. This suggests that at the MHC-I and MHC-IIB respectively, different evolutionary dynamics may govern the evolution of within-haplotype diversity.
Assuntos
Evolução Molecular , Haplótipos , Complexo Principal de Histocompatibilidade/genética , Alelos , Sequência de Aminoácidos , Ligação Genética , Alinhamento de SequênciaRESUMO
BACKGROUND: Gene duplication has led to a most remarkable adaptation involved in vertebrates' host-pathogen arms-race, the major histocompatibility complex (MHC). However, MHC duplication history is as yet poorly understood in non-mammalian vertebrates, including birds. RESULTS: Here, we provide evidence for the evolution of two ancient avian MHC class IIB (MHCIIB) lineages by a duplication event prior to the radiation of all extant birds >100 million years ago, and document the role of concerted evolution in eroding the footprints of the avian MHCIIB duplication history. CONCLUSIONS: Our results suggest that eroded footprints of gene duplication histories may mimic birth-death evolution and that in the avian MHC the presence of the two lineages may have been masked by elevated rates of concerted evolution in several taxa. Through the presence of a range of intermediate evolutionary stages along the homogenizing process of concerted evolution, the avian MHCIIB provides a remarkable illustration of the erosion of multigene family duplication history.
Assuntos
Aves/genética , Evolução Molecular , Genes MHC da Classe II/genética , Família Multigênica/genética , Animais , Duplicação GênicaRESUMO
Understanding how speciation relates to ecological divergence has long fascinated biologists. It is assumed that ecological divergence is essential to sympatric speciation, as a mechanism to avoid competition and eventually lead to reproductive isolation, while divergence in allopatry is not necessarily associated with niche differentiation. The impact of the spatial context of divergence on the evolutionary rates of abiotic dimensions of the ecological niche has rarely been explored for an entire clade. Here, we compare the magnitude of climatic niche shifts between sympatric versus allopatric divergence of lineages in butterflies. By combining next-generation sequencing, parametric biogeography and ecological niche analyses applied to a genus-wide phylogeny of Palaearctic Pyrgus butterflies, we compare evolutionary rates along eight climatic dimensions across sister lineages that diverged in large-scale sympatry versus allopatry. In order to examine the possible effects of the spatial scale at which sympatry is defined, we considered three sets of biogeographic assignments, ranging from narrow to broad definition. Our findings suggest higher rates of niche evolution along all climatic dimensions for sister lineages that diverge in sympatry, when using a narrow delineation of biogeographic areas. This result contrasts with significantly lower rates of climatic niche evolution found in cases of allopatric speciation, despite the biogeographic regions defined here being characterized by significantly different climates. Higher rates in allopatry are retrieved when biogeographic areas are too widely defined-in such a case allopatric events may be recorded as sympatric. Our results reveal the macro-evolutionary significance of abiotic niche differentiation involved in speciation processes within biogeographic regions, and illustrate the importance of the spatial scale chosen to define areas when applying parametric biogeographic analyses.
Assuntos
Evolução Biológica , Borboletas/fisiologia , Clima , Ecossistema , África do Norte , Animais , Ásia , Borboletas/genética , Europa (Continente) , Especiação Genética , Filogenia , SimpatriaRESUMO
BACKGROUND: The burden of disease caused by Streptococcus agalactiae has increased significantly among older adults in the last decades. Group B streptococcus infection can be associated with invasive disease and severe clinical syndromes, such as meningitis and endocarditis. CASE PRESENTATION: We present the case of a 56-year-old man who developed multiple mycotic aneurysms of the right hepatic artery and massive splenic infarction as rare complications of Streptococcus agalactiae infective endocarditis. The patient underwent urgent right hepatic artery ligation and splenectomy. The postoperative course was complicated by an episode of hemobilia due to the rupture of a partially thrombosed mycotic aneurysm into the biliary tree. Thus, selective radiological embolization of the left hepatic artery branches was necessary. CONCLUSION: To our knowledge, this is the first case reported of infected aneurysms of visceral arteries caused by Group B streptococcus infection. Clinical and laboratory findings were non-specific, while imaging features with computed tomography scan and angiography were highly suggestive. In our case, early recognition, culture-specific intravenous antibiotics and urgent surgical treatment combined with interventional radiology played a decisive role in the final result.
Assuntos
Aneurisma Infectado/complicações , Endocardite Bacteriana/complicações , Hepatopatias/complicações , Infarto do Baço/complicações , Streptococcus agalactiae , Aneurisma Infectado/microbiologia , Aneurisma Infectado/cirurgia , Antibacterianos/uso terapêutico , Endocardite Bacteriana/tratamento farmacológico , Humanos , Hepatopatias/microbiologia , Hepatopatias/cirurgia , Masculino , Pessoa de Meia-Idade , Esplenectomia , Infarto do Baço/microbiologia , Infarto do Baço/cirurgiaRESUMO
Recent studies found fish egg-specific bacterial communities that changed over the course of embryogenesis, suggesting an interaction between the developing host and its microbiota. Indeed, single-strain infections demonstrated that the virulence of opportunistic bacteria is influenced by environmental factors and host immune genes. However, the interplay between a fish embryo host and its microbiota has not been studied yet at the community level. To test whether host genetics affects the assemblage of egg-associated bacteria, adult brown trout (Salmo trutta) were sampled from a natural population. Their gametes were used for full-factorial in vitro fertilizations to separate sire from dam effects. In total, 2520 embryos were singly raised under experimental conditions that differently support microbial growth. High-throughput 16S rRNA amplicon sequencing was applied to characterize bacterial communities on milt and fertilized eggs across treatments. Dam and sire identity influenced embryo mortality, time until hatching and composition of egg-associated microbiotas, but no link between bacterial communities on milt and on fertilized eggs could be found. Elevated resources increased embryo mortality and modified bacterial communities with a shift in their putative functional potential. Resource availability did not significantly affect any parental effects on embryo performance. Sire identity affected bacterial diversity that turned out to be a significant predictor of hatching time: embryos associated with high bacterial diversity hatched later. We conclude that both host genetics and the availability of resources define diversity and composition of egg-associated bacterial communities that then affect the life history of their hosts.