Sex differences in condition dependence of natal dispersal in a large herbivore: dispersal propensity and distance are decoupled.

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.

A stochastic movement simulator improves estimates of landscape connectivity.

Conservation actions often focus on restoration or creation of natural areas designed to facilitate the movements of organisms among populations. To be efficient, these actions need to be based on reliable estimates or predictions of landscape connectivity. While circuit theory and least-cost paths (LCPs) are increasingly being used to estimate connectivity, these methods also have proven limitations. We compared their performance in predicting genetic connectivity with that of an alternative approach based on a simple, individual-based "stochastic movement simulator" (SMS). SMS predicts dispersal of organisms using the same landscape representation as LCPs and circuit theory-based estimates (i.e., a cost surface), while relaxing key LCP assumptions, namely individual omniscience of the landscape (by incorporating perceptual range) and the optimality of individual movements (by including stochasticity in simulated movements). The performance of the three estimators was assessed by the degree to which they correlated with genetic estimates of connectivity in two species with contrasting movement abilities (Cabanis's Greenbul, an Afrotropical forest bird species, and natterjack toad, an amphibian restricted to European sandy and heathland areas). For both species, the correlation between dispersal model and genetic data was substantially higher when SMS was used. Importantly, the results also demonstrate that the improvement gained by using SMS is robust both to variation in spatial resolution of the landscape and to uncertainty in the perceptual range model parameter. Integration of this individual-based approach with other developing methods in the field of connectivity research, such as graph theory, can yield rapid progress towards more robust connectivity indices and more effective recommendations for land management.

The link between behavioural type and natal dispersal propensity reveals a dispersal syndrome in a large herbivore.

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.

Utility of Ki67 immunostaining in the grading of pineal parenchymal tumours: a multicentre study.

AIMS: Pineal parenchymal tumours (PPTs) are rare neoplasms that are divided into pineocytoma (PC), pineoblastoma (PB) and PPT of intermediate differentiation (PPTID). Factors affecting the survival of patients with PPTs are morphological subtype and histological grading according to mitotic index and neurofilament immunostaining. Grading criteria to distinguish PPTIDs are difficult to define, particularly when using small specimens. The Ki67 labelling index (LI) might be helpful in distinguishing between grade II and III PPTIDs. Our study was performed to assess the predictive value of the Ki67 LI in a large cooperative series of PPTs and to evaluate whether inclusion of this data would improve and refine the World Health Organization classification. METHODS: A retrospective analysis of 33 PPTs was performed. The histological features of the tumours were reviewed and Ki67 LI scoring was evaluated by immunohistochemistry. Data were correlated with the patients' survival. RESULTS: The mean Ki67 LI was significantly different for tumour grades (0 in PC, 5.2 ± 0.4 in PPTID grade II, 11.2 ± 2.0 in PPTID grade III, 36.4 ± 6.2 in PB; P < 0.0001). However, there was no statistically significant difference in either overall or disease-free survival evaluated by the Kaplan-Meier method for patients with different grade tumours or Ki67 LI, possibly due to the different clinical management of patients in different centres. CONCLUSIONS: The Ki67 LI may be a useful additional tool for grading PPTs, more particularly in small tumour samples.

Infected hepatic cyst complicating urinary sepsis.

Congenital hepatic cysts are a common disorder. Usually they are asymptomatic and do not have to be treated. However, some serious complications can occur. We report here the case of an 86-year old patient who has been treated by a percutaneous drainage for an infected solitary hepatic cyst due to urinary sepsis. She was admitted to the Department of Internal Medicine for epigastric pain with fever and chills. The patient was treated for a urinary tract infection 3 weeks ago by her General Practitioner. On admission, blood tests showed 21 620 neutrophils per microliter with a C-reactive protein level at 443.7 mg/L, procalcitonin > 200 ng/mL, total bilirubin at 1.43 mg/dL, lactate dehydrogenase at 666 U/L and alanine aminotransferase at 227 U/L. Urinalysis and hemocultures highlighted the presence of Escherichia coli and Streptococcus constellatus. The abdominal tomodensitometry indicated the presence of a left hepatic biliary cyst with banal appearance. She was first treated with intravenous amoxicillin clavulanic acid. After a few days, another abdominal tomodensitometry with contrast pinpointed a large abscess of 11 centimeters in diameter extending to liver segments II and IV with a similar small lesion in segments IV and V. clindamycin per os was added to the treatment because of its good diffusion in tissues. Percutaneous drain was inserted under tomodensitometric control and stayed in place until the follow-up at three weeks. Bacteriologic culture on the fluid sample demonstrated the presence of Escherichia coli and Streptococcus constellatus. The abscess completely regressed after 6 weeks of treatment and the biologic abnormalities resolved at the same time.

Monthly mobility inferred from isoscapes and laser ablation strontium isotope ratios in caprine tooth enamel.

Strontium isotopic analysis of sequentially formed tissues, such as tooth enamel, is commonly used to study provenance and mobility of humans and animals. However, the potential of 87Sr/86Sr in tooth enamel to track high-frequency movements has not yet been established, in part due to the lack of data on modern animals of known movement and predictive model of isotope variation across the landscape. To tackle this issue, we measured the 87Sr/86Sr in plant samples taken from a 2000 km2 area in the Altai Mountains (Mongolia), and the 87Sr/86Sr in tooth enamel of domestic caprines whose mobility was monitored using GPS tracking. We show that high-resolution, sequential profiles of strontium isotope composition of tooth enamel reliably reflect the high-frequency mobility of domestic livestock and that short-term residency of about 45 days can be resolved. This offers new perspectives in various disciplines, including forensics, ecology, palaeoanthropology, and bioarchaeology.

[Pathologic characteristics of the most frequent peripheral nerve tumors]. / Aspects histopathologiques des principales tumeurs des nerfs périphériques.

Benign tumors of the peripheral nerves come from ectodermic tissues. This chapter describes the most common forms: the schwannomas and the neurofibromas. Schwannomas have two possible patterns of cells: Antoni A and B types. Neurofibromas are most often associated with neurofibromatosis NF1 and may be localized, diffuse, or plexiform. The benign tumor structures account for the fact that they can be removed with or without preserving the concerned nerve. Malignant tumors (malignant peripheral sheath tumors) come from degeneration of neurofibromas in two out of three cases and have a poor prognosis.

Population density and sex do not influence fine-scale natal dispersal in roe deer.

It is commonly assumed that the propensity to disperse and the dispersal distance of mammals should increase with increasing density and be greater among males than among females. However, most empirical evidence, especially on large mammals, has focused on highly polygynous and dimorphic species displaying female-defence mating tactics. We tested these predictions on roe deer, a weakly polygynous species of large herbivore exhibiting a resource-defence mating tactic at a fine spatial scale. Using three long-term studies of populations that were subject to the experimental manipulation of size, we did not find any support for either prediction, whether in terms of dispersal probability or dispersal distance. Our findings of similar dispersal patterns in both sexes of roe deer suggest that the underlying cause of natal dispersal is not related to inbreeding avoidance in this species. The absence of positive density dependence in fine-scale dispersal behaviour suggests that roe deer natal dispersal is a pre-saturation process that is shaped by heterogeneities in habitat quality rather than by density per se.

Congruent population structure inferred from dispersal behaviour and intensive genetic surveys of the threatened Florida scrub-jay (Aphelocoma coerulescens).

The delimitation of populations, defined as groups of individuals linked by gene flow, is possible by the analysis of genetic markers and also by spatial models based on dispersal probabilities across a landscape. We combined these two complimentary methods to define the spatial pattern of genetic structure among remaining populations of the threatened Florida scrub-jay, a species for which dispersal ability is unusually well-characterized. The range-wide population was intensively censused in the 1990s, and a metapopulation model defined population boundaries based on predicted dispersal-mediated demographic connectivity. We subjected genotypes from more than 1000 individual jays screened at 20 microsatellite loci to two Bayesian clustering methods. We describe a consensus method for identifying common features across many replicated clustering runs. Ten genetically differentiated groups exist across the present-day range of the Florida scrub-jay. These groups are largely consistent with the dispersal-defined metapopulations, which assume very limited dispersal ability. Some genetic groups comprise more than one metapopulation, likely because these genetically similar metapopulations were sundered only recently by habitat alteration. The combined reconstructions of population structure based on genetics and dispersal-mediated demographic connectivity provide a robust depiction of the current genetic and demographic organization of this species, reflecting past and present levels of dispersal among occupied habitat patches. The differentiation of populations into 10 genetic groups adds urgency to management efforts aimed at preserving what remains of genetic variation in this dwindling species, by maintaining viable populations of all genetically differentiated and geographically isolated populations.

Dispersal is not female biased in a resource-defence mating ungulate, the European roe deer.

Dispersal is frequently more prevalent in one sex compared to the other. Greenwood proposed that patterns of sex-biased dispersal among birds and mammals are linked to their mating strategies. For species where males defend resources rather than females, he predicted female-biased dispersal, because males should remain at their birth site where they are familiar with the distribution of the resources that they must defend. Greenwood's hypothesis has been extensively supported among birds, where most species exhibit a resource-defence mating strategy. However, almost no equivalent information is available for mammals as males generally defend mates in this group. An exception is the European roe deer, a resource-defence mating ungulate. We thus tested Greenwood's hypothesis on this atypical mammalian model, looking for female-biased dispersal using sex-specific inter-individual genetic distances. We conclusively show that gene flow is not higher among females compared to males in the studied roe deer population, and hence that dispersal is not female-biased, suggesting that male mating strategy is not the primary selective force driving the evolution of dispersal in roe deer. We discuss the role of female mate choice and intra-sexual competition as possible alternative selective pressures involved.

Fluctuation Analysis: Dissecting Transcriptional Kinetics with Signal Theory.

Recent live-cell microscopy techniques now allow the visualization in multiple colors of RNAs as they are transcribed on genes of interest. Following the number of nascent RNAs over time at a single locus reveals complex fluctuations originating from the underlying transcriptional kinetics. We present here a technique based on concepts from signal theory-called fluctuation analysis-to analyze and interpret multicolor transcriptional time traces and extract the temporal signatures of the underlying mechanisms. The principle is to generate, from the time traces, a set of functions called correlation functions. We explain how to compute these functions practically from a set of experimental traces and how to interpret them through different theoretical and computational means. We also present the major difficulties and pitfalls one might encounter with this technique. This approach is capable of extracting mechanistic information hidden in transcriptional fluctuations at multiple timescales and has broad applications for understanding transcriptional kinetics.

[Spontaneous intraperitoneal rupture of the ureter]. / Rupture intrapéritonéale spontanée de l'uretère.

An unusual case of spontaneous intraperitoneal rupture of the ureter was observed in adult with acute renal pain. Diagnosis was best established with CT rather than intravenous urography. CT demonstrated ureteral leakage with the contrast medium extravasating into the peritoneal cavity. The patient was initially managed successfully by endourology. Secondary stenosis of the ureter required surgery for partial resection of the distal ureter.

[Imaging of osteoarticular tuberculosis]. / Imagerie de la tuberculose ostéo-articulaire.

PURPOSE: and methods. To perform an illustrated and educational review of musculoskeletal tuberculosis. RESULTS: As the incidence of musculoskeletal tuberculosis still increases, a review appears justified. The following four main presentations are detailed and illustrated, by emphasizing the value of both CT and MR imaging: a) spine tuberculosis (~ 50%) commonly involves two adjacent vertebral bodies with usual large paravertebral abscesses. The following lesions are highly suggestive of tuberculosis: solitary vertebral involvement, solitary epidural abscess with or without erosive spondylitis; b) osteo-arthritis: peripherally located erosions at synovial insertions with gradual narrowing of the joint space are highly suggestive; c) osteomyelitis: unusual, may involve any bones; d) tenosynovitis and bursitis. CONCLUSION: Imaging studies are essential for diagnosis and to assess the extent of musculo-skeletal tuberculosis.

Radio-histological correlations of subtle sonography images.

Breast lesions may, during their development, provide sonography signs can be difficult to view or are not very specific. They are called "subtle images". Proximal (ductal) lesions are differentiated from distal (ductal-lobular) lesions. Proximal lesions are mainly inflammatory or infectious, altering the duct walls that evolve into ectasia and then fibrosis with possible acute episodes of plasmocyte mastitis or bacterial mastitis. The fibrovascular stalks of the papilloma accounts for the Doppler flow. Certain secretory forms of intra-ductal carcinoma may distend the structure of the milk ducts. The sonography of lesions of the ductal-lobular units are related to the degree of fibrosis, the atrophy or cell proliferation, and the disorganisation of the architecture. The extent of the fibrosis, or the cell density of certain tumours may modify the tissue hardness in elastography.

Individual caspase-10 isoforms play distinct and opposing roles in the initiation of death receptor-mediated tumour cell apoptosis.

The cysteine protease caspase-8 is an essential executioner of the death receptor (DR) apoptotic pathway. The physiological function of its homologue caspase-10 remains poorly understood, and the ability of caspase-10 to substitute for caspase-8 in the DR apoptotic pathway is still controversial. Here, we analysed the particular contribution of caspase-10 isoforms to DR-mediated apoptosis in neuroblastoma (NB) cells characterised by their resistance to DR signalling. Silencing of caspase-8 in tumour necrosis factor-related apoptosis-inducing ligand (TRAIL)-sensitive NB cells resulted in complete resistance to TRAIL, which could be reverted by overexpression of caspase-10A or -10D. Overexpression experiments in various caspase-8-expressing tumour cells also demonstrated that caspase-10A and -10D isoforms strongly increased TRAIL and FasL sensitivity, whereas caspase-10B or -10G had no effect or were weakly anti-apoptotic. Further investigations revealed that the unique C-terminal end of caspase-10B was responsible for its degradation by the ubiquitin-proteasome pathway and for its lack of pro-apoptotic activity compared with caspase-10A and -10D. These data highlight in several tumour cell types, a differential pro- or anti-apoptotic role for the distinct caspase-10 isoforms in DR signalling, which may be relevant for fine tuning of apoptosis initiation.