Fate of cadmium in rat renal tubules: a micropuncture study.

Free-flow micropuncture was carried out in superficial nephrons of Munich-Wistar type rats infused acutely with Cd acetate (CdA) or Cd-DTPA (141 microM Cd). Fluid obtained from Bowman's space (BS) or end-proximal tubule sites was analyzed for Cd and inulin. The fluid/plasma Cd concentration ratio in BS averaged 0.2 and 1.0 during CdA and Cd-DTPA infusions, respectively. End-proximal tubule fractional excretion of Cd during CdA infusion averaged 0.34. Previous administration of CdA (1.0 mg/kg, 48 hr before micropuncture) increased the level of circulating Cd-metallothioneins, as measured by radioimmunoassay, but did not affect the luminal tubular uptake of Cd during CdA infusion. No net transepithelial movement of Cd-DTPA was measured. It is concluded that Cd ultrafiltered during inorganic Cd administration is taken up to a large extent by the convoluted part of proximal tubules.

Fate of cadmium in rat renal tubules: a microinjection study.

109Cd was injected into the lumen of superficial proximal or distal tubules of rat kidneys, and recovery in the pelvic urine from the ipsilateral kidney was measured. Fractional recovery of labeled inulin always exceeded 90%. About 70% of injected inorganic Cd (CdCl2) was taken up by the epithelium of proximal tubules, while more than 90% of the injected amount was recovered after distal microinjection. The proximal fractional Cd uptake of a 1:1 (molar) Cd-L-cysteine complex was 82%, but was below 60% for a 5-10:1 molar ratio of cysteine:Cd. The chelate Cd-pentetic acid was recovered in final urine nearly quantitatively after proximal or distal microinjection. Fractional uptake of 109Cd from a Cd-metallothionein (Mt) complex, following proximal microinjection, ranged between 17 (Cd-Mt 0.19 mM) and 8% (Cd-Mt 1.5 mM). It is concluded that luminal Cd uptake by the tubular epithelium depends markedly on the chemical form of Cd and, when present, occurs mostly or exclusively in proximal tubules.

Birth Weight, Working Memory and Epigenetic Signatures in IGF2 and Related Genes: A MZ Twin Study.

Neurodevelopmental disruptions caused by obstetric complications play a role in the etiology of several phenotypes associated with neuropsychiatric diseases and cognitive dysfunctions. Importantly, it has been noticed that epigenetic processes occurring early in life may mediate these associations. Here, DNA methylation signatures at IGF2 (insulin-like growth factor 2) and IGF2BP1-3 (IGF2-binding proteins 1-3) were examined in a sample consisting of 34 adult monozygotic (MZ) twins informative for obstetric complications and cognitive performance. Multivariate linear regression analysis of twin data was implemented to test for associations between methylation levels and both birth weight (BW) and adult working memory (WM) performance. Familial and unique environmental factors underlying these potential relationships were evaluated. A link was detected between DNA methylation levels of two CpG sites in the IGF2BP1 gene and both BW and adult WM performance. The BW-IGF2BP1 methylation association seemed due to non-shared environmental factors influencing BW, whereas the WM-IGF2BP1 methylation relationship seemed mediated by both genes and environment. Our data is in agreement with previous evidence indicating that DNA methylation status may be related to prenatal stress and later neurocognitive phenotypes. While former reports independently detected associations between DNA methylation and either BW or WM, current results suggest that these relationships are not confounded by each other.

Reversal of a full-length mutant huntingtin neuronal cell phenotypeby chemical inhibitors of polyglutamine-mediated aggregation

Background: Huntington's disease (HD) is an inherited neurodegenerative disorder triggered by an expanded polyglutamine tract in huntingtin that is thought to confer a new conformational property on this large protein. The propensity of small amino-terminal fragments with mutant, but not wild-type, glutamine tracts to self-aggregate is consistent with an altered conformation but such fragments occur relatively late in the disease process in human patients and mouse models expressing full-length mutant protein. This suggests that the altered conformational property may act within the full-length mutant huntingtin to initially trigger pathogenesis. Indeed, genotypephenotype studies in HD have defined genetic criteria for the disease initiating mechanism, and these are all fulfilled by phenotypes associated with expression of full-length mutant huntingtin, but not amino-terminal fragment, in mouse models. As the in vitro aggregation of amino-terminal mutant huntingtin fragment offers a ready assay to identify small compounds that interfere with the conformation of the polyglutamine tract, we have identified a number of aggregation inhibitors, and tested whether these are also capable of reversing a phenotype caused by endogenous expressionof mutant huntingtin in a striatal cell line from the HdhQ111/Q111 knock-in mouse. Results: We screened the NINDS Custom Collection of 1,040 FDA approved drugs and bioactive compounds for their ability to prevent in vitro aggregation of Q58-htn 1¿171 amino terminal fragment. Ten compounds were identified that inhibited aggregation with IC50 < 15 ¿M, including gossypol, gambogic acid, juglone, celastrol, sanguinarine and anthralin. Of these, both juglone and celastrol were effective in reversing the abnormal cellular localization of full-length mutant huntingtin observed in mutant HdhQ111/Q111 striatal cells. Conclusions: At least some compounds identified as aggregation inhibitors also prevent a neuronal cellular phenotype caused by full-length mutant huntingtin, suggesting that in vitro fragment aggregation can act as a proxy for monitoring the disease-producing conformational property in HD. Thus, identification and testing of compounds that alter in vitro aggregation is a viable approach for defining potential therapeutic compounds that may act on the deleterious conformational property of full-length mutant huntingtin.

A mild form of SLC29A3 disorder: a frameshift deletion leads to the paradoxical translation of an otherwise noncoding mRNA splice variant

We investigated two siblings with granulomatous histiocytosis prominent in the nasal area, mimicking rhinoscleroma and Rosai-Dorfman syndrome. Genome-wide linkage analysis and whole-exome sequencing identified a homozygous frameshift deletion in SLC29A3, which encodes human equilibrative nucleoside transporter-3 (hENT3). Germline mutations in SLC29A3 have been reported in rare patients with a wide range of overlapping clinical features and inherited disorders including H syndrome, pigmented hypertrichosis with insulin-dependent diabetes, and Faisalabad histiocytosis. With the exception of insulin-dependent diabetes and mild finger and toe contractures in one sibling, the two patients with nasal granulomatous histiocytosis studied here displayed none of the many SLC29A3-associated phenotypes. This mild clinical phenotype probably results from a remarkable genetic mechanism. The SLC29A3 frameshift deletion prevents the expression of the normally coding transcripts. It instead leads to the translation, expression, and function of an otherwise noncoding, out-of-frame mRNA splice variant lacking exon 3 that is eliminated by nonsense-mediated mRNA decay (NMD) in healthy individuals. The mutated isoform differs from the wild-type hENT3 by the modification of 20 residues in exon 2 and the removal of another 28 amino acids in exon 3, which include the second transmembrane domain. As a result, this new isoform displays some functional activity. This mechanism probably accounts for the narrow and mild clinical phenotype of the patients. This study highlights the"rescue" role played by a normally noncoding mRNA splice variant of SLC29A3, uncovering a new mechanism by which frameshift mutations can be hypomorphic.

An Advocacy for the Use of 3D Stem Cell Culture Systems for the Development of Regenerative Medicine: An Emphasis on Photoreceptor Generation

The availability of stem cells is of great promise to study early developmental stages and to generate adequate cells for cell transfer therapies. Although many researchers using stem cells were successful in dissecting intrinsic and extrinsic mechanisms and in generating specific cell phenotypes, few of the stem cells or the differentiated cells show the capacity to repair a tissue. Advances in cell and stem cell cultivation during the last years made tremendous progress in the generation of bona fide differentiated cells able to integrate into a tissue after transplantation, opening new perspectives for developmental biology studies and for regenerative medicine. In this review, we focus on the main works attempting to create in vitro conditions mimicking the natural environment of CNS structures such as the neural tube and its development in different brain region areas including the optic cup. The use of protocols growing cells in 3D organoids is a key strategy to produce cells resembling endogenous ones. An emphasis on the generation of retina tissue and photoreceptor cells is provided to highlight the promising developments in this field. Other examples are presented and discussed, such as the formation of cortical tissue, the epithelial gut or the kidney organoids. The generation of differentiated tissues and well-defined cell phenotypes from embryonic stem (ES) cells or induced pluripotent cells (iPSCs) opens several new strategies in the field of biology and regenerative medicine. A 3D organ/tissue development in vitro derived from human cells brings a unique tool to study human cell biology and pathophysiology of an organ or a specific cell population. The perspective of tissue repair is discussed as well as the necessity of cell banking to accelerate the progress of this promising field.

High prevalence of PRPH2 in autosomal dominant retinitis pigmentosa in france and characterization of biochemical and clinical features.

PURPOSE: To assess the prevalence of PRPH2 in autosomal dominant retinitis pigmentosa (adRP), to report 6 novel mutations, to characterize the biochemical features of a recurrent novel mutation, and to study the clinical features of adRP patients. DESIGN: Retrospective clinical and molecular genetic study. METHODS: Clinical investigations included visual field testing, fundus examination, high-resolution spectral-domain optical coherence tomography (OCT), fundus autofluorescence imaging, and electroretinogram (ERG) recording. PRPH2 was screened by Sanger sequencing in a cohort of 310 French families with adRP. Peripherin-2 protein was produced in yeast and analyzed by Western blot. RESULTS: We identified 15 mutations, including 6 novel and 9 previously reported changes in 32 families, accounting for a prevalence of 10.3% in this adRP population. We showed that a new recurrent p.Leu254Gln mutation leads to protein aggregation, suggesting abnormal folding. The clinical severity of the disease in examined patients was moderate with 78% of the eyes having 1-0.5 of visual acuity and 52% of the eyes retaining more than 50% of the visual field. Some patients characteristically showed vitelliform deposits or macular involvement. In some families, pericentral RP or macular dystrophy were found in family members while widespread RP was present in other members of the same families. CONCLUSIONS: The mutations in PRPH2 account for 10.3% of adRP in the French population, which is higher than previously reported (0%-8%) This makes PRPH2 the second most frequent adRP gene after RHO in our series. PRPH2 mutations cause highly variable phenotypes and moderate forms of adRP, including mild cases, which could be underdiagnosed.

Jasmonic acid and the THO/TREX complex participate in phosphate starvation response

All plants are typically confronted to simultaneous biotic and abiotic stress throughout their life cycle. Low inorganic phosphate (Pi) is the most common nutrient deficiency limiting plant growth in natural and agricultural ecosystems while insect herbivory accounts for major losses in plant productivity and impacts on ecological and evolutionary changes in plant populations. Here we report that plants experiencing Pi deficiency induce the jasmonic acid (JA) pathway and enhance their defence against insect herbivory. The phol mutant is impaired in the translocation of Pi from roots to shoots and shows the typical symptoms associated with Pi deficiency, including high anthocyanin and poor shoot growth. These phol shoot phenotypes were significantly attenuated by blocking the JA biosynthesis or signalling pathways. Wounded phol leaves hyper-accumulated JA in comparison to wild type, leading to increased resistance against the generalist herbivore Spodoptera littoralis. Pi deficiency also triggered enhanced resistance to herbivory in wild-type Arabidopsis as well as tomato and tobacco, revealing that the link between Pi deficiency and JA-mediated herbivory resistance is conserved in a diversity of plants, including crops. We performed a phol suppressor screen to identify new components involved in the adaptation of plants to Pi deficiency. We report that the THO RNA TRANSCRIPTION AND EXPORT (THO/TREX) complex is a crucial component involved in modulating the Pi- deficiency response. Knockout mutants of at least three members of the THO/TREX complex, including TEX1, HPR1, and TH06, can suppress the phol shoot phenotype. Grafting experiments showed that loss of function of TEX1 only in the root was sufficient to suppress the reduced shoot growth phenotype of phol while maintaining low Pi contents. This indicates that TEX1 is involved in a long distance root-to-shoot signalling component of the Pi-deficiency response. We identified a small MYB-like transcription factor, RAD LIKE 3 (RL3), as a potential downstream target of the THO/TREX complex. RL3 expression is induced in phol mutants but attenuated in phol-7 texl-4 double mutants. Identical to knockout mutants of the THO/TREX complex, rl3 mutants can suppress the phol shoot phenotypes. Interestingly, RL3 is induced during Pi deficiency and is described in the literature as likely being mobile. It is therefore a promising new candidate involved in the root-to-shoot Pi-deficiency signalling response. Finally, we report that PHOl and its homologue PH01:H3 are involved in the co-regulation of Pi and zinc (Zn) homeostasis. PH01;H3 is up-regulated in response to Zn deficiency and, like PHOl, is expressed in the root vascular cylinder and localizes to the Golgi when expressed transiently in tobacco cells. The phol;h3 mutant accumulates more Pi as compared to wild-type when grown in Zn-deficient medium, but this increase is abolished in the phol phol;h3 double mutant. These results suggest that PH01;H3 restricts the PHOl-mediated root-to-shoot Pi transfer in responsé to Zn deficiency. Résumé Au cours de leur cycle de vie, toutes les plantes sont généralement confrontées à divers stress biotiques et abiotiques. La carence nutritionnelle la plus fréquente, limitant la croissance des plantes dans les écosystèmes naturels et agricoles, est la faible teneur en phosphate inorganique (Pi). Au niveau des stress biotiques, les insectes herbivores sont responsables de pertes majeures de rendement et ont un impact considérable sur les changements écologiques et évolutifs dans les populations des plantes. Au cours de ce travail, nous avons mis en évidence que les plantes en situation de carence en Pi induisent la voie de l'acide jasmonique (JA) et augmentent leur défense contre les insectes herbivores. Le mutant phol est déficient dans le transport du phosphate des racines aux feuilles et démontre les symptômes typiques associés à la carence, tels que la forte concentration en anthocyane et une faible croissance foliaire. Ces phénotypes du mutant phol sont significativement atténués lors d'un blocage de la voie de la biosynthèse ou des voies de signalisation du JA. La blessure des feuilles induit une hyper-accumulation de JA chez phol, résultant en une augmentation de la résistance contre l'herbivore généraliste Spodoptera littoralis. Outre Arabidopsis, la carence en Pi induit une résistance accrue aux insectes herbivores aussi chez la tomate et le tabac. Cette découverte révèle que le lien entre la carence en Pi et la résistance aux insectes herbivores via le JA est conservé dans différentes espèces végétales, y compris les plantes de grandes cultures. Nous avons effectué un crible du suppresseur de phol afin d'identifier de nouveaux acteurs impliqués dans l'adaptation de la plante à la carence en Pi. Nous rapportons que le complexe nommé THO RNA TRANSCRIPTION AND EXPORT (THO/TREX) est un élément crucial participant à la réponse des feuilles à la carence en Pi. Les mutations d'au moins trois des membres que composent le complexe THO/TREX, incluant TEX1, HPR1 et 77/06, peuvent supprimer le phénotype de phol. Des expériences de greffes ont montré que la perte de fonction de TEX1, seulement dans la racine, est suffisante pour supprimer le phénotype de la croissance réduite des parties aériennes observé chez le mutant phol, tout en maintenant de faibles teneurs en Pi foliaire. Ceci indique que TEX1 est impliqué dans la signalisation longue distance entre les racines et les parties aériennes. Nous avons identifié un petit facteur de transcription proche de la famille des MYB, RAD LIKE 3 (RL3), comme une cible potentielle en aval du complexe THO / TREX. L'expression du gène RL3 est induite dans le mutant phol mais atténuée dans le double mutant phol-7 texl-4. Exactement comme les plantes mutées d'un des membres du complexe THO/TREX, le mutant rl3 peut supprimer le phénotype foliaire de phol. RL3 est induit au cours d'une carence en Pi et est décrit dans la littérature comme étant potentiellement mobile. Par conséquent, il serait un nouveau candidat potentiellement impliqué dans la réponse longue distance entre les racines et les parties aériennes lors d'un déficit en Pi. Enfin, nous reportons que PHOl et son homologue PHOl: H3 sont impliqués dans la co- régulation de l'homéostasie du Pi et du zinc (Zn). PHOl; H3 est sur-exprimé en réponse au déficit en Zn et, comme PHOl, est exprimé dans les tissus vasculaires des racines et se localise dans l'appareil de Golgi lorsqu'il est exprimé de manière transitoire dans des cellules de tabac. Le mutant phol; h3 accumule plus de Pi par rapport aux plantes sauvages lorsqu'il est cultivé sur un milieu déficient en Zn, mais cette augmentation en Pi est abolie dans le double mutant phol phol; h3. Ces résultats suggèrent qu'en réponse à une carence en Zn, PHOl; H3 limite l'action de PHOl et diminue le transfert du Pi des racines aux parties aériennes.

Identificació de nous gens que participen en la remodelació del sistema traqueal de Drosophila melanogaster

Un dels organismes model més utilitzats en experimentació genètica és la Drosophila melanogaster ja que la facilitat de manipulació genètica i la seva simplicitat permeten estudiar processos biològics amb múltiples aplicabilitats en diferents àmbits d’estudi com el desenvolupament embrionari i la morfogènesis. La morfogènesi es un dels esdeveniments més importants durant el desenvolupament embrionari que permet la formació dels diferent teixits i òrgans, i que depèn de l'expressió genètica i de l'activació i coordinació de diferents vies de senyalització. Entendre com es coordinen aquest processos es fonamental per conèixer com es forma un òrgan. Així, l’objectiu principal d’aquest Treball de Final de Grau és identificar nous gens implicats en la formació del sistema traqueal (el nostre òrgan model) mitjançant un mini-­‐cribratge funcional de gens que s’expressen en la tràquea, a més de generar eines per a l'estudi de la via de senyalització FGF/Bnl durant la remodelació del sistema traqueal mitjançant la tècnica de knock in. Per a dur-­‐ho a terme, amb el suport de la base de dades de Gens i Genomes de Drosophila melanogaster (mod-­‐ENCODE Tissue Expression Data) s’han seleccionat gens candidats expressats a la tràquea en estat larvari. Un cop identificats, s'ha estudiat la seva possible funció en el desenvolupament de les tràquees mitjançant el seu silenciament amb el sistema UAS-­‐Gal4. Així hem vist que Vein (CG10491), CG17098, No Ocelli (CG4491) i Peptidasa (CG4017) presenten diversos fenotips que afecten la formació dels traqueoblasts. També hem vist que Vein, lligand de la via EGF és necessari per a la proliferació i supervivència de les cèl·∙lules traqueals del sac aeri. Finalment s’ha iniciat la generació d'un knock in en el gen branchless (bnl). Per aquest motiu s'han amplificat les regions 5’ i 3’ de l’exó 2 del gen Bnl i s'ha iniciat la seva clonació dirigida al vector de destí pTV-­‐Cherry. Aquesta tècnica generarà eines que permetran entendre la funció del gen bnl durant la remodelació del sistema traqueal.

Functional impact of genetic variation on gene expression

Numerous links between genetic variants and phenotypes are known and genome-wide association studies dramatically increased the number of genetic variants associated with traits during the last decade. However, how changes in the DNA perturb the molecular mechanisms and impact on the phenotype of an organism remains elusive. Studies suggest that many traitassociated variants are in the non-coding region of the genome and probably act through regulation of gene expression. During my thesis I investigated how genetic variants affect gene expression through gene regulatory mechanisms. The first chapter was a collaborative project with a pharmaceutical company, where we investigated genome-wide copy number variation (CNVs) among Cynomolgus monkeys (Macaca fascicularis) used in pharmaceutical studies, and associated them to changes in gene expression. We found substantial copy number variation and identified CNVs linked to tissue-specific expression changes of proximal genes. The second and third chapters focus on genetic variation in humans and its effects on gene regulatory mechanisms and gene expression. The second chapter studies two human trios, where the allelic effects of genetic variation on genome-wide gene expression, protein-DNA binding and chromatin modifications were investigated. We found abundant allele specific activity across all measured molecular phenotypes and show extended coordinated behavior among them. In the third chapter, we investigated the impact of genetic variation on these phenotypes in 47 unrelated individuals. We found that chromatin phenotypes are organized into local variable modules, often linked to genetic variation and gene expression. Our results suggest that chromatin variation emerges as a result of perturbations of cis-regulatory elements by genetic variants, leading to gene expression changes. The work of this thesis provides novel insights into how genetic variation impacts gene expression by perturbing regulatory mechanisms. -- De nombreux liens entre variations génétiques et phénotypes sont connus. Les études d'association pangénomique ont considérablement permis d'augmenter le nombre de variations génétiques associées à des phénotypes au cours de la dernière décennie. Cependant, comprendre comment ces changements perturbent les mécanismes moléculaires et affectent le phénotype d'un organisme nous échappe encore. Des études suggèrent que de nombreuses variations, associées à des phénotypes, sont situées dans les régions non codantes du génome et sont susceptibles d'agir en modifiant la régulation d'expression des gènes. Au cours de ma thèse, j'ai étudié comment les variations génétiques affectent les niveaux d'expression des gènes en perturbant les mécanismes de régulation de leur expression. Le travail présenté dans le premier chapitre est un projet en collaboration avec une société pharmaceutique. Nous avons étudié les variations en nombre de copies (CNV) présentes chez le macaque crabier (Macaca fascicularis) qui est utilisé dans les études pharmaceutiques, et nous les avons associées avec des changements d'expression des gènes. Nous avons découvert qu'il existe une variabilité substantielle du nombre de copies et nous avons identifié des CNVs liées aux changements d'expression des gènes situés dans leur voisinage. Ces associations sont présentes ou absentes de manière spécifique dans certains tissus. Les deuxième et troisième chapitres se concentrent sur les variations génétiques dans les populations humaines et leurs effets sur les mécanismes de régulation des gènes et leur expression. Le premier se penche sur deux trios humains, père, mère, enfant, au sein duquel nous avons étudié les effets alléliques des variations génétiques sur l'expression des gènes, les liaisons protéine-ADN et les modifications de la chromatine. Nous avons découvert que l'activité spécifique des allèles est abondante abonde dans tous ces phénotypes moléculaires et nous avons démontré que ces derniers ont un comportement coordonné entre eux. Dans le second, nous avons examiné l'impact des variations génétiques de ces phénotypes moléculaires chez 47 individus, sans lien de parenté. Nous avons observé que les phénotypes de la chromatine sont organisés en modules locaux, qui sont liés aux variations génétiques et à l'expression des gènes. Nos résultats suggèrent que la variabilité de la chromatine est due à des variations génétiques qui perturbent des éléments cis-régulateurs, et peut conduire à des changements dans l'expression des gènes. Le travail présenté dans cette thèse fournit de nouvelles pistes pour comprendre l'impact des différentes variations génétiques sur l'expression des gènes à travers les mécanismes de régulation.

Combined deletion of cathepsin protease family members reveals compensatory mechanisms in cancer.

Proteases are important for regulating multiple tumorigenic processes, including angiogenesis, tumor growth, and invasion. Elevated protease expression is associated with poor patient prognosis across numerous tumor types. Several multigene protease families have been implicated in cancer, including cysteine cathepsins. However, whether individual family members have unique roles or are functionally redundant remains poorly understood. Here we demonstrate stage-dependent effects of simultaneously deleting cathepsin B (CtsB) and CtsS in a murine pancreatic neuroendocrine tumor model. Early in tumorigenesis, the double knockout results in an additive reduction in angiogenic switching, whereas at late stages, several tumorigenic phenotypes are unexpectedly restored to wild-type levels. We identified CtsZ, which is predominantly supplied by tumor-associated macrophages, as the compensatory protease that regulates the acquired tumor-promoting functions of lesions deficient in both CtsB and CtsS. Thus, deletion of multiple cathepsins can lead to stage-dependent, compensatory mechanisms in the tumor microenvironment, which has potential implications for the clinical consideration of selective versus pan-family cathepsin inhibitors in cancer.

Reciprocal preening and food sharing in colour-polymorphic nestling barn owls.

Barn owl (Tyto alba) siblings preen and offer food items to one another, behaviours that can be considered prosocial because they benefit a conspecific by relieving distress or need. In experimental broods, we analysed whether such behaviours were reciprocated, preferentially exchanged between specific phenotypes, performed to avoid harassment and food theft or signals of hierarchy status. Three of the results are consistent with the hypothesis of direct reciprocity. First, food sharing was reciprocated in three-chick broods but not in pairs of siblings, that is when nestlings could choose a partner with whom to develop a reciprocating interaction. Second, a nestling was more likely to give a prey item to its sibling if the latter individual had preened the former. Third, siblings matched their investment in preening each other. Manipulation of age hierarchy showed that food stealing was directed towards older siblings but was not performed to compensate for a low level of cooperation received. Social behaviours were related to melanin-based coloration, suggesting that animals may signal their propensity to interact socially. The most prosocial phenotype (darker reddish) was also the phenotype that stole more food, and the effect of coloration on prosocial behaviour depended upon rank and sex, suggesting that colour-related prosociality is state dependent.

Obstrução duodenal por hematoma parietal pós-trauma: relato de caso e revisão da literatura

Os hematomas parietais de alças intestinais por trauma abdominal fechado, determinando rápida obstrução luminal, são lesões raras e podem ser confundidas com afecções neoplásicas estenosantes (parietais ou por mecanismo de compressão extrínseca). Neste estudo é relatado um caso de obstrução intestinal por hematoma parietal da terceira porção duodenal pós-trauma e são discutidos o diagnóstico por imagem e o tratamento para tal obstrução.

Environmental influence on the phenotype of ant workers revealed by common garden experiment

Many organism traits vary along environmental gradients. Common garden experiments provide powerful means to disentangle the role of intrinsic factors, such as genetic or maternal effects, from extrinsic environmental factors in shaping phenotypic variation. Here, we investigate body size and lipid content variation in workers of the socially polymorphic ant Formica selysi along several independent elevation gradients in Switzerland. We compare field-collected workers and workers sampled as eggs from the same colonies but reared in common laboratory conditions. Overall, field-collected workers from high elevation are larger than those from low elevation, but the trend varies substantially among valleys. The same pattern is recovered when the eggs are reared in a common garden, which indicates that body size variation along elevation gradients and valleys is partly explained by genetic or maternal effects. However, both body size and lipid content exhibit significantly greater variation in field-collected workers than in laboratory-reared workers. Hence, much of the phenotypic variation results from a plastic response to the environment, rather than from genetic differences. Eggs from different elevations also show no significant difference in development time in the common garden. Overall, selection on individual worker phenotypes is unlikely to drive the altitudinal distribution of single- and multiple-queen colonies in this system, as phenotypic variation tends to be plastic and can be decoupled from social structure. This study provides insights into the interplay between individual phenotypic variation and social organization and how the two jointly respond to differing environmental conditions.

Genomics of clinal variation in Drosophila: disentangling the interactions of selection and demography.

Clines in phenotypes and genotype frequencies across environmental gradients are commonly taken as evidence for spatially varying selection. Classical examples include the latitudinal clines in various species of Drosophila, which often occur in parallel fashion on multiple continents. Today, genomewide analysis of such clinal systems provides a fantastic opportunity for unravelling the genetics of adaptation, yet major challenges remain. A well-known but often neglected problem is that demographic processes can also generate clinality, independent of or coincident with selection. A closely related issue is how to identify true genic targets of clinal selection. In this issue of Molecular Ecology, three studies illustrate these challenges and how they might be met. Bergland et al. report evidence suggesting that the well-known parallel latitudinal clines in North American and Australian D. melanogaster are confounded by admixture from Africa and Europe, highlighting the importance of distinguishing demographic from adaptive clines. In a companion study, Machado et al. provide the first genomic comparison of latitudinal differentiation in D. melanogaster and its sister species D. simulans. While D. simulans is less clinal than D. melanogaster, a significant fraction of clinal genes is shared between both species, suggesting the existence of convergent adaptation to clinaly varying selection pressures. Finally, by drawing on several independent sources of evidence, Bo?ičević et al. identify a functional network of eight clinal genes that are likely involved in cold adaptation. Together, these studies remind us that clinality does not necessarily imply selection and that separating adaptive signal from demographic noise requires great effort and care.