Prognostic significance of histopathology in canine anal sac gland adenocarcinomas: Preliminary results in a retrospective study of 39 cases.

Metastatic rates and survival times of canine anal sac gland adenocarcinomas (ASGACs) vary among studies, making prognostication difficult. Little is known about the prognostic significance of histopathology of ASGACs. This retrospective study investigated associations between histological features, clinical presentation and outcome for 39 ASGACs. Most tumours were incompletely excised (62%) and had moderate to marked peripheral infiltration (74%). The predominant growth pattern was solid, tubules/rosettes/pseudorosettes and papillary in 49%, 46% and 5% of the cases, respectively. Nuclear pleomorphism was either moderate (77%) or mild (23%). Necrosis and lymphovascular invasion were present in 54% and 10% of the cases, respectively. All histological features except mitotic count and necrosis were associated with nodal metastasis at presentation. A statistically significant poorer outcome was identified for tumours with a solid growth pattern, moderate or marked peripheral infiltration, necrosis and lymphovascular invasion. These results need further validation in a larger cohort of dogs.

One Health, One Caribbean, One Love ­ Caribbean Leadership, Regional Cooperation, Local Action

Inter-sectoral collaboration is extremely limited, both at policy and technical levels, across the Caribbean region. However, many of the priority health problems currently facing the region, like climate change, food security, ocean health, and emerging diseases arise from the interactions between people, animals and our shared environment. If these health issues are to be addressed effectively and efficiently, an intersectoral or One Health approach is clearly required. The European Union funded project "One Health, One Caribbean, One Love" set out to promote and entrench a "One Health" approach to priority health issues affecting humans, animals and the environment within the Caribbean region. The project, which spanned from March 2014 and ended in June 2017, successfully built the capacity of the national veterinary, public health and environmental health services, through the development of a cadre of One Health Leaders, the creation of Caribbean regional and national One Health Networks, and the development of a One Health strategic framework. The One Health Leadership Series developed a core group of One Health Leaders from 12 Caribbean countries. The leaders attended a series of 5 themed One Health Leadership workshops, and each country team developed and conducted a One Health project addressing a national priority health issue at the interface between human, animal and environmental health ­ a learning by doing approach. The One Health leadership series has enabled the leaders to more effectively design and manage One Health policies, programs and projects in order to develop more holistic scientific solutions to emerging health problems.

Parapatric distribution and sexual competition between two tick species, Amblyomma variegatum and A. hebraeum (Acari, Ixodidae), in Mozambique.

BACKGROUND: Amblyomma variegatum and A. hebraeum are two ticks of veterinary and human health importance in south-east Africa. In Zimbabwe they occupy parapatric (marginally overlapping and juxtaposed) distributions. Understanding the mechanisms behind this parapatry is essential for predicting the spatio-temporal dynamics of Amblyomma spp. and the impacts of associated diseases. It has been hypothesized that exclusive competition between these species results from competition at the levels of male signal reception (attraction-aggregation-attachment pheromones) or sexual competition for mates. This hypothesis predicts that the parapatry described in Zimbabwe could also be present in other countries in the region. METHODS: To explore this competitive exclusion hypothesis we conducted field surveys at the two species' range limits in Mozambique to identify areas of sympatry (overlapping areas) and to study potential interactions (communicative and reproductive interference effects) in those areas. At sympatric sites, hetero-specific mating pairs were collected and inter-specific attractiveness/repellent effects acting at long and short distances were assessed by analyzing species co-occurrences on co-infested herds and co-infested hosts. RESULTS: Co-occurrences of both species at sampling sites were infrequent and localized in areas where both tick and host densities were low. At sympatric sites, high percentages of individuals of both species shared attachment sites on hosts and inter-specific mating rates were high. Although cross-mating rates were not significantly different for A. variegatum and A. hebraeum females, attraction towards hetero-specific males was greater for A. hebraeum females than for A. variegatum females and we observed small asymmetrical repellent effects between males at attachment sites. CONCLUSIONS: Our observations suggest near-symmetrical reproductive interference between A. variegatum and A. hebraeum, despite between-species differences in the strength of reproductive isolation barriers acting at the aggregation, fixation and partner contact levels. Theoretical models predict that sexual competition coupled with hybrid inviability, greatly reduces the probability of one species becoming established in an otherwise suitable location when the other species is already established. This mechanism can explain why the parapatric boundary in Mozambique has formed within an area of low tick densities and relatively infrequent host-mediated dispersal events.

Developing a disease prevention strategy in the Caribbean: the importance of assessing animal health-related risks at regional level.

In 2009 CaribVET conducted a survey among Caribbean national Veterinary Services to assess perceptions of risk assessment and to identify the principal exotic diseases of concern in the region and their means of introduction. The results showed that the introduction of live animals was considered the most likely route of introduction of exotic animal pathogens, followed by the uncontrolled introduction of animal products by boat passengers. The results were used to define a regional strategy for assessing animal health risks that highlights the importance of within-region exchanges.

Is Culex modestus (Diptera: Culicidae), vector of West Nile virus, spreading in the Dombes area, France?

As a main vector of West Nile (WN) virus (family Flaviviridae, genus Flavivirus) in Europe, Culex modestus Ficalbi (Diptera: Culicidae) is commonly found in delta regions, lakes, and ponds. The Dombes area is located along one of the main corridors of bird migrations in France and lies 300 km north of the Camargue region, a frequent focus of WN virus circulation. It is an important breeding, wintering, and stopover site for many bird species that are putative carriers of viruses of different kinds. It is also a continental wetland with approximately =1200 fish farming ponds, scattered over the area, that provide suitable breeding sites for Cx. modestus. This article reports an entomological study based on larval surveys conducted in ponds in 2007 to assess the prevalence and abundance of Cx. modestus in the Dombes. Using the larval survey as an ecological screening test, we investigated the proportion of ponds found positive for Cx. modestus, and the relative abundance of this species was estimated in larval samples. We found that its pond distribution was more extensive in the 2007 survey than in that conducted in the 1970s. Survey methods and meteorological and anthropological factors that could account for the differences or variations between the findings of the two investigations are discussed.

Risk factors for West Nile virus seropositivity of equids in Guadeloupe.

In Guadeloupe, West Nile virus (WNV) activity was first observed in equids in 2002, and a high seroprevalence was found in 2003. The objective of our study was to determine individual and environmental factors associated with the risk of WNV seropositivity during 2002-2003. Fieldwork was conducted to retrospectively determine the location of equids at the time of virus circulation and to collect information regarding environmental and individual variables. Sera were collected from 369 equids out of an estimated total population of less than 500. Thirty-four environmental and individual variables were investigated. Equids had a higher risk (p<0.001) for WNV seropositivity if they lived within the proximity "distance less than 1.5km" of marshes or swamp forests "a large freshwater formation behind mangroves" or if they remained outside after dusk. Equids living within the proximity of ouassous shrimp (Macrobrachium rosenbergii) basins or sugar cane fields had a lower risk (p<0.001) for WNV seropositivity. These results confirm that WNV circulation is more likely in the humid coastal areas of Guadeloupe. The identification of risk factors is useful for predicting future emergence sites of WNV in the archipelago and other Neotropical islands, and to better target sentinel surveillance in the region.

DWnt4 and wingless elicit similar cellular responses during imaginal development.

Wnt genes encode evolutionarily conserved secreted proteins that provide critical functions during development. Although Wnt proteins share highly conserved features, they also show sequence divergence, which almost certainly contributes to the variety of their signaling activities. We previously reported that DWnt4 and wingless (wg), two divergent clustered Wnt genes, can have either antagonist or distinct functions during Drosophila embryogenesis. Here we provide evidence that both genes can elicit similar cellular responses during imaginal development. Ectopic expression of DWnt4 along the anterior/posterior (A/P) boundary of imaginal discs alters morphogenesis of adult appendages. In the wing disc, DWnt4 phenocopies ectopic Wg activity by inducing notum to wing transformation, suggesting similar signaling capabilities of both molecules. In support of this, we demonstrate that DWnt4 can rescue wg loss-of-function phenotypes in the antenna and haltere and is able to substitute for Wg in wing field specification. We also show that both genes are transcribed in overlapping domains in imaginal discs, suggesting that DWnt4 may cooperate with wg during limb patterning.

Pontin52 and reptin52 function as antagonistic regulators of beta-catenin signalling activity.

In Wnt-stimulated cells, beta-catenin becomes stabilized in the cytoplasm, enters the nucleus and interacts with HMG box transcription factors of the lymphoid-enhancing factor-1 (LEF-1)/T-cell factor (TCF) family, thereby stimulating the transcription of specific target genes. We recently identified Pontin52 as a nuclear protein interacting with beta-catenin and the TATA-box binding protein (TBP), suggesting its involvement in regulating beta-catenin-mediated transactivation. Here, we report the identification of Reptin52 as an interacting partner of Pontin52. Highly homologous to Pontin52, Reptin52 likewise binds beta-catenin and TBP. Using reporter gene assays, we show that the two proteins antagonistically influence the transactivation potential of the beta-catenin-TCF complex. Furthermore, we demonstrate the evolutionary conservation of this mechanism in Drosophila. dpontin and dreptin are essential genes that act antagonistically in the control of Wingless signalling in vivo. These results indicate that the opposite action of Pontin52 and Reptin52 on beta-catenin-mediated transactivation constitutes an additional mechanism for the control of the canonical Wingless/Wnt pathway.

dlarp, a new candidate Hox target in Drosophila whose orthologue in mouse is expressed at sites of epithelium/mesenchymal interactions.

Hox complex genes are key developmental regulators highly conserved throughout evolution. They encode transcription factors that initiate genetic programs of diversified morphogenesis along the anteroposterior embryonic axis. We report the characterization of the novel Drosophila Hox target gene dlarp, isolated from a further screen of a previously described library of genomic DNA fragments associated in vivo with Ultrabithorax proteins. The dlarp spatio-temporal pattern of transcription in wild-type and homeotic mutant embryos is consistent with a positive regulation by Sex combs reduced and Ultrabithorax in the parasegment 2 ectoderm and the abdominal mesoderm, respectively. The teashirt gene product, thought to act in concert with Hox proteins, is also required for the transcriptional control of this target. Search in databases revealed that dlarp has been highly conserved during evolution. The embryonic expression pattern of the mouse orthologue does not support a function downstream of Hox proteins. It is mainly transcribed in neural structures and in developing organs characterized by epithelial-mesenchymal interactions.

Dynamic expression of d-CdGAPr, a novel Drosophila melanogaster gene encoding a GTPase activating protein.

Small GTPases of the rho family function as signal transducer for extra-cellular stimuli to control cytoskeletal re-organization and a variety of other cellular processes including adhesion, proliferation and transcriptional regulation (Hall, A., 1998. RhoGTPases and the actin cytoskeleton. Science 279, 509-514). Usually widely expressed, their activities are tightly controlled by conformational changes induced by hydrolysis of the GTP bound molecule (Bourne H.R., Sanders D.A., 1990. The GTPase superfamily: a conserved switch for diverse cell functions. Nature 348, 125-132). Conversion of GTP to GDP relies on a rho intrinsic GTPase domain that requires GTPase activating proteins (GAPs) for potent activity (Lamarche, N., Hall. A., 1994. GAPs for rho-related GTPases. Trends Genet. 10, 436-440). Here we report on the identification of a novel Drosophila GAP gene, d-CdGAPr, encoding a protein related to mammalian CdGAPs. The gene is expressed throughout development as well as in adults. Spatio-temporal transcription pattern of d-CdGAPr during embryogenesis is highly dynamic. Abundant in the pre-blastoderm embryo prior to the onset of zygotic transcription, messengers accumulate at the blastoderm posterior pole after cellularisation. During gastrulation and subsequent development, all cells accumulate low levels of d-CdGAPr RNA, while a few territories transiently display stronger expression. Sites of preferential expression include the posterior pole of the early cellular blastoderm, the neuro-ectoderm prior to neuroblast delamination, rows of epidermal cells in the most posterior part of thoracic and first abdominal segments and a ring of epidermal cells at the posterior end of the embryo.

Distinct hox protein sequences determine specificity in different tissues.

Hox genes encode evolutionarily conserved transcription factors that control the morphological diversification along the anteroposterior (A/P) body axis. Expressed in precise locations in the ectoderm, mesoderm, and endoderm, Hox proteins have distinct regulatory activities in different tissues. How Hox proteins achieve tissue-specific functions and why cells lying at equivalent A/P positions but in different germ layers have distinctive responses to the same Hox protein remains to be determined. Here, we examine this question by identifying parts of Hox proteins necessary for Hox function in different tissues. Available genetic markers allow the regulatory effects of two Hox proteins, Abdominal-A (AbdA) and Ultrabithorax (Ubx), to be distinguished in the Drosophila embryonic epidermis and visceral mesoderm (VM). Chimeric Ubx/AbdA proteins were tested in both tissues and used to identify protein sequences that endow AbdA with a different target gene specificity from Ubx. We found that distinct protein sequences define AbdA, as opposed to Ubx, function in the epidermis vs. the VM. These sequences lie mostly outside the homeodomain (HD), emphasizing the importance of non-HD residues for specific Hox activities. Hox tissue specificity is therefore achieved by sensing distinct Hox protein structures in different tissues.

DWnt-4 and Wingless have distinct activities in the Drosophila dorsal epidermis.

Wnt genes are often expressed in overlapping patterns, where they affect a wide array of developmental processes. To address the way in which various Wnt signals elicit distinct effects we compared the activities of two Wnt genes in Drosophila, DWnt-4, and wingless. We show that these Wnt signals produce distinct responses in cells of the dorsal embryonic epidermis. Whereas wingless acts independently of hedgehog signaling in these cells, we show that DWnt-4 requires Hh to elicit its effects. We also show that expression of Wg signal transduction components does not mimic expression of DWnt-4, suggesting that DWnt-4 signaling proceeds through a distinct pathway. The dorsal epidermis may therefore be useful in the identification of novel Wnt signaling components.

nessy, an evolutionary conserved gene controlled by Hox proteins during Drosophila embryogenesis.

From a library of DNA fragments associated with Ultrabithorax protein in vivo, we have isolated nessy, a new Drosophila gene that encodes a putative transmembrane protein conserved in evolution from Caenorhabditis elegans, to human. Zygotic expression occurs transiently in mesectodermal cells at gastrulation, proceeds in mesoderm and endoderm lineages during germ band movements and becomes then restricted to anterior and posterior domains in the visceral mesoderm. The Hox proteins Ultrabithorax, Antennapedia and AbdominalA are likely acting simultaneously to repress nessy in the other parts of the visceral mesoderm.

Antagonist activity of DWnt-4 and wingless in the Drosophila embryonic ventral ectoderm and in heterologous Xenopus assays.

Wnt genes encode secreted signalling molecules involved in a number of basic developmental processes. In Drosophila, wingless and DWnt-4 are two physically clustered Wnt genes, which are transcribed in overlapping patterns during embryogenesis and, in several instances, are controlled by the same regulatory molecules. To address the question of the functional relationship of wingless and DWnt-4, we analysed how embryonic cells respond when they are exposed, simultaneously or not, to the encoded Wnt signals. We show that DWnt-4 has the capacity to antagonise Wingless signalling both in the Drosophila ventral epidermis and in a heterologous system, the Xenopus embryo. We provide evidence that DWnt-4 inhibits the Wingless/Wnt-1 signalling pathway upstream of the activation of transcriptional targets. This is the first report that antagonising Wnt signals exist in Drosophila.

The Drosophila modifier of variegation modulo gene product binds specific RNA sequences at the nucleolus and interacts with DNA and chromatin in a phosphorylation-dependent manner.

modulo belongs to the modifier of Position Effect Variegation class of Drosophila genes, suggesting a role for its product in regulating chromatin structure. Genetics assigned a second function to the gene, in protein synthesis capacity. Bifunctionality is consistent with protein localization in two distinct subnuclear compartments, chromatin and nucleolus, and with its organization in modules potentially involved in DNA and RNA binding. In this study, we examine nucleic acid interactions established by Modulo at nucleolus and chromatin and the mechanism that controls the distribution and balances the function of the protein in the two compartments. Structure/function analysis and oligomer selection/amplification experiments indicate that, in vitro, two basic terminal domains independently contact DNA without sequence specificity, whereas a central RNA Recognition Motif (RRM)-containing domain allows recognition of a novel sequence-/motif-specific RNA class. Phosphorylation moreover is shown to down-regulate DNA binding. Evidence is provided that in vivo nucleolar Modulo is highly phosphorylated and belongs to a ribonucleoprotein particle, whereas chromatin-associated protein is not modified. A functional scheme is finally proposed in which modification by phosphorylation modulates Mod subnuclear distribution and balances its function at the nucleolus and chromatin.

Doppler study of mesenteric, hepatic, and portal circulation in alcoholic cirrhosis: relationship between quantitative Doppler measurements and the severity of portal hypertension and hepatic failure.

To determine the relationship between quantitative Doppler parameters of portal, hepatic, and splanchnic circulation and hepatic venous pressure gradient (HVPG), variceal size, and Child-Pugh class in patients with alcoholic cirrhosis, we studied forty patients with proved alcoholic cirrhosis who underwent Doppler ultrasonography, hepatic vein catheterization, and esophagoscopy. The following Doppler parameters were recorded: time-averaged mean blood velocity, volume flow of the main portal vein flow, and resistance index (RI) of the hepatic and of the superior mesenteric artery. Doppler findings were compared with HVPG, presence and size of esophageal varices, and Child-Pugh class. There was a significant inverse correlation between portal velocity and HVPG (r = -.69), as well as between portal vein flow and HVPG (r = -.58). No correlation was found between RI in the hepatic artery or superior mesenteric artery and HVPG. No correlation was found between portal vein measurements and presence and size of varices. Severe liver failure was associated with lower portal velocity and flow. In patients with alcoholic cirrhosis, only portal vein blood velocity and flow, but neither hepatic nor mesenteric artery RI, are correlated to the severity of portal hypertension and to the severity of liver failure.

Dynamics of the sub-nuclear distribution of Modulo and the regulation of position-effect variegation by nucleolus in Drosophila.

modulo belongs to the class of Drosophila genes named 'suppressor of position-effect variegation', suggesting the involvement of the encoded protein in chromatin compaction/relaxation processes. Using complementary procedures of cell fractionation, immunolocalisation on mitotic and polytene chromosomes and cross-linking/immunoprecipitation of genomic DNA targets, we have analysed the sub-nuclear distribution of Modulo. While actually associated to condensed chromatin and heterochromatin sites, the protein is also abundantly found at nucleolus. From a comparison of Modulo pattern on chromosomes of different cell types and mutant lines, we propose a model in which the nucleolus balances the Modulo protein available for chromatin compaction and PEV modification. At a molecular level, repetitive elements instead of rDNA constitute Modulo DNA targets, indicating that the protein directly contacts DNA in heterochromatin but not at the nucleolus. Consistent with a role for Modulo in nucleolus activity and protein synthesis capacity, somatic clones homozygous for a null mutation express a cell-autonomous phenotype consisting of growth alteration and short slender bristles, characteristic traits of Minute mutations, which are known to affect ribosome biogenesis. The results provide evidence suggesting that Modulo participates in distinct molecular networks in the nucleolus and heterochromatin and has distinct functions in the two compartments.

From selectors to realizators.

In 1975 Antonio Garcia-Bellido proposed a framework for understanding the morphogenetic function of homeotic genes in terms of selector genes and realizator genes. Since then, much has been learnt of the molecular nature and expression patterns of the Hox selector genes. Our identification of realizator genes, and our understanding of how specific sets of realizators are activated in different segments, is still far from complete, however. Here we discuss the nature of the Hox target genes identified so far and the basis of the target specificity of Hox gene products.

Doppler study of fasting and postprandial resistance indices in the superior mesenteric artery in healthy subjects and patients with cirrhosis.

PURPOSE: We assessed the resistance index (RI) in the superior mesenteric artery under fasting and postprandial conditions in healthy subjects and in patients with cirrhosis to determine whether the amount of change in the RI reflects the presence or severity of liver dysfunction. METHODS: Fifteen subjects with normal livers and 27 patients with cirrhosis underwent Doppler sonography of the superior mesenteric artery before and after ingesting a standard meal. The RI at baseline (fasting state) and the postprandial RI were compared between the 2 groups. The fasting RIs and post postprandial RIs changes in cirrhotic patients were correlated with the severity of disease. RESULTS: No difference was found between the baseline RIs in healthy (RI = 0.85) and cirrhotic subjects (RI = 0.84), nor was there a difference in baseline RIs between subgroups of cirrhotic patients according to the severity of liver disease. The RI decreased significantly (p < 0.05) after the meal in both the healthy (13%) and cirrhotic (8%) subjects, but the postprandial decrease was significantly less pronounced (p < 0.05) in cirrhotic patients than in healthy subjects. Among cirrhotic patients, there was no correlation between the postprandial decrease of the RI and severity of liver disease. CONCLUSIONS: The marked decrease in the postprandial RI in the SMA in healthy subjects is generally not seen in patients with cirrhosis, and changes in the postprandial RI do not reliably predict the severity of liver dysfunction.