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.

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.

A 4-vinylprotochlorophyllide complex accumulated by "phofil" mutant of Rhodopseudomonas spheroides. An authentic intermediate in the development of the photosynthetic apparatus.

A photosynthetically competent mutant strain of Rhodopseudomonas spheroides was isolated. In addition to bacteriochlorophyll, this organism produced particle-bound precursor 4-vinylprotochlorophyllide. The spectral characteristics of the pigment complexes(es) accumulated in the culture medium were very variable. The spectral form occurring within the bacteria was characterized from fluorescence data. Its particle weight, 130 000, was determined by Sephadex G200 filtration. The main components of the complex were protein, lipid and pigment (6.8:61, w/w). As indicated by qualitative analysis, the lipid components were characteristic constituents of the photosynthetic membrane. Kinetics of pigments synthesis showed that the total pigment synthesis was not affected by the mutation; bacteriochlorophyll content was always lower in the mutant than in the parent strain. The repigmentation process was followed by fluorescence emission. The results indicated that the mutation affected membrane component synthesis required for the bacteriochlorophyll(ide) incorporation. The pigment complex was concluded to be an authentic intermediate in photosynthetic apparatus morphogenesis. The reasons for its excretion are discussed.

Formation and development of photosynthetic units in repigmenting Rhodopseudomonas sphaeroides wild type and "Phofil" mutant strain.

The formation of the photosynthetic apparatus in the wild type Rhodopseudomonas sphaeroides and in the "Phofil" mutant was investigated by analyzing absorption and fluorescence parameters and the kinetics of fluorescence induction. Repigmentation was induced by transfer of bleached cells to semi-aerobic culture conditions. 1. In the "Phofil" mutant, functional photosynthetic units appear at pigment cellular contents which depend on the physiological state of the inoculum. The unadapted mutant can reach the functional units stage at a cellular pigment level 20 times lower than that of the wild type, although the size and composition of the units are identical in both strains. This rules out the hypothesis of photosynthetic units forming by random integration of pigments into the membrane. Moreover, the fact that units are separate at this stage (as shown by the exponential shape of fluorescence induction kinetics) suggests that the units' formation proceeds from discrete predetermined membrane sites. 2. In repigmentng wild type cells, the multistep assembly of bacteriochlorophyll complexes appears correlated to their organization in photosynthetic units as follows: (i) During a first stage, B-875 is mostly synthesized, while the efficiency of transfer increases, suggesting that the pigments are initially interpersed at comparatively large average distances from each other in the bleached membrane. (ii) After 1.5 h of repigmentation, the transfer and trapping efficiencies reach a maximum. The units (26 B-875 + 11 B-850 per center) are still separate, as shown by exponential fluorescence kinetics. (iii) The increase in the units' size then essentially proceeds through B-850 incorporation. Energy transfer between units occurs at a comparatively late stage, i.e., 5 h repigmentation.

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.

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.

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.

The Drosophila teashirt homeotic protein is a DNA-binding protein and modulo, a HOM-C regulated modifier of variegation, is a likely candidate for being a direct target gene.

The Drosophila teashirt (tsh) gene has an homeotic function which, in combination with HOM-C genes, determines thoracic and abdominal (trunk) identities. Analysis of TSH protein distribution during embryogenesis using a specific polyclonal antibody shows that it is nuclear. The protein is present with regional modulation in several tissues within the trunk, suggesting additional tsh functions to those already studied. We identified a candidate tsh target shared with some HOM-C genes, the modifier of variegation gene modulo (mod). The TSH zinc-finger protein recognizes in vitro two specific sites within a 5' control element of the mod gene which responds in vivo to tsh activity. TSH is therefore a DNA binding protein and might directly control mod expression.

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.

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.

Genetic and molecular analysis of terminal deletions of chromosome 3R of Drosophila melanogaster.

Terminal deletions of chromosome 3R are induced at a high frequency (3.2 x 10(-3)) by irradiating 45-4 Drosophila melanogaster females with a low dose of X-rays. The 45-4 line carries a white transgene inserted at 16 kb from the terminus and is homozygous for the mu-2 mutation, a gene involved in the repair of double-strand DNA breaks. Four of the 51 recovered deleted strains have lost modulo, the distalmost essential gene on chromosome 3R. Breakpoints of 22 deletions have been localised in a single hybridisation step, using pulsed-field gel electrophoresis to separate genomic DNA fragments obtained from digestion with a rare-cutter restriction enzyme. Breaks do not occur at random, but are rather clustered in three susceptible chromosomal domains. Backcross experiments resulting in transheterozygous (deleted chromosome/45-4) animals indicate that the activity of the white transgene is enhanced when the DNA break has occurred proximal to a critical position. This suggests that homologous chromosomal pairing distal to the critical position results in the definition of a more compact chromatin structure and, due to position effect, in the silencing of white.

Sodium cromoglycate, verapamil and nicardipine antagonism to leukotriene D4 bronchoconstriction.

1--The effects of nicardipine, verapamil and sodium cromoglycate (SCG) on the increase in pulmonary airway resistance(RAw) and decrease in pulmonary dynamic compliance (CDyn) induced by leukotriene D4 (LTD4) 0.5 micrograms kg-1 and acetylcholine (ACh) 3 micrograms kg-1 were investigated in anaesthetized guinea-pigs. The effects of these three agents on the contractile effects of LTD4 and ACh were tested on isolated tracheal preparations of the guinea-pig. 2--Nicardipine and verapamil (0.3 and 1 mg kg-1), as well as SCG (3 and 10 mg kg-1), partially but significantly inhibited the effects of LTD4 on RAw. Partial inhibition of the effect of LTD4 on CDyn was only observed with verapamil (0.3 and 1 mg kg-1). Nicardipine and verapamil had no effect on ACh-induced bronchoconstriction in vivo. 3--In concentrations higher than 10(-5) M, nicardipine and verapamil inhibited the contractile effects of LTD4 and ACh on guinea-pig isolated trachea. SCG had no effect on this preparation. 4--These results suggest that nicardipine, verapamil and SCG partially reduce the component of bronchoconstriction associated with stimulation of irritant receptors by LTD4. However, the site and mechanism of action of Ca2+-entry antagonists remain uncertain.

Role of CT in the acute nontraumatic abdomen.

The diagnostic workup of the acute abdomen always begins with a precise clinical history, a complete physical examination, and careful reading of plain films. Commonly performed additional imaging studies include contrast examination and, more recently, ultrasound. CT offers the advantage of allowing a comprehensive diagnostic evaluation of both solid and hollow viscera in neoplastic as well as in inflammatory and vascular disorders.

[Failure factors of guided puncture of hepatic masses]. / Facteurs d'échec de la ponction guidée des masses hépatiques.

This study was carried out to assess the failure factors of guided hepatic mass puncture in 320 biopsies. Results of the puncture, follow-up or surgery allowed us to divide 320 biopsies into true positives or false negatives. Compared with the group of true positive diagnosis, the group of false negative diagnosis revealed a significantly higher percentage either of lesions less than 2 cm (52.5% versus 34%), of benign tumors (19% versus 5%), or of pseudotumors (24% versus 1.5%). Compared with the group with cytology and histology diagnosis, the group in which only histology established the diagnosis revealed a significantly higher percentage of hepatocellular carcinoma (52.5% versus 34%) and of benign tumors (21% versus 0%). A diameter less than 2 cm, a histology of benign tumors or pseudotumors, are failure factors of guided biopsy. The use of histology is useful for the diagnosis of benign tumors and increases the accuracy of diagnosis for hepatocellular carcinoma.

[Value of percutaneous hepatic biopsy in the diagnosis of presumed benign tumors of the liver]. / Valeur de la ponction biopsie hépatique percutanée dans le diagnostic des tumeurs présumées bénignes du foie.

The purpose of this study was to assess the accuracy of guided hepatic biopsy (GHB) and imaging techniques for presumed benign liver tumours and to determine their impact on surgical treatment. The study was carried out retrospectively in a surgical series of 15 consecutive patients with presumed benign liver tumours. The final diagnosis was 8 cases of focal nodular hyperplasia (FNH), 6 hepatic adenomas (HA) and one association FNH-HA. No morbidity was related to guided hepatic biopsy. All FNH detected on radiologic imaging or pathological examination of the biopsy specimen were true positive diagnoses. This study demonstrates that combined results of imaging techniques and percutaneous GHB could correctly diagnose three quarters of FNH before surgery. GHB is also useful when MRI imaging is indeterminate allowing a conservative approach for undiagnosed FNH.

[The posterior interparieto-peritoneal or retroperitoneal spaces. 2: Pathological x-ray computed tomographic image]. / Les espaces interpariétopéritonéaux postérieurs ou espaces rétropéritonéaux. 2 Partie: Anatomie tomodensitométrique pathologique.

The old reports about the interparieto-peritoneal spaces described particularly the renal space and its environment. The CT scan has modified the in vivo study of the extraperitoneal spaces (E.P.S.) and brought the question of the acquired knowledge up again. An anatomical research was performed in the first part of this study which describes the structures limited between the parietalis fascia and visceral peritoneal fascias. These are the true EPS which the main element is the propria fascia of Sappey (lateroconal fascia) and its anterior and posterior renal double layers. All these lamellar structures limits spaces variably infiltrated with fat tissue: the anterior pararenal space almost virtual, the posterior pararenal space which continues till the Bogros space and the anterior and posterior renal spaces of the renal compartment which the fat continues till the bladder and accompanies the ureter. The second part of this study precises some notions of general topography which are necessary for reading abnormal CT scan images. This part reminds the aortic and arterial general organization of the vertebrates as described by Mackay. It underlines the architectural importance of the three areas so defined: parietal or peripheral, intermediate or mesoblastic genitourinary and deep lateral or digestive endoblastic. These three areas corresponds to the three vascular aortic circles. It emphasized the importance to accept in practice the notion of visceral joining fascia which has been proved in adult people. The longitudinal architecture of the compartments is precise with respect to their appartenance to one among the three arterial arches of Mackay. What the anatomy suggest, the pathology can prove. Several pathological processes are studied on CT scan: large hemorrhagic or necrotic collections in acute pancreatitis, abnormalities or diseases of renal or adrenal compartments, extraperitoneal mesenchymomas, diseases of the psoas compartment. All these observations are analysed in order to explain anatomical and CT scan findings. This study refers not only to the oldest researches which are still valuable but also to the most recent controversies. All the questions are not solved using the clearest schemes.

[The posterior interparietoperitoneal spaces or retroperitoneal spaces. 1: Normal topographic anatomy]. / Les espaces interpariéto-péritonéaux postérieurs ou espaces rétropéritonéaux. 1re partie: Anatomie topographique normale.

The posterior spaces between the wall and peritoneum or extraperitoneal spaces are located between the visceral retrocolic and retro-duodenopancreatic fascias anteriorly and the parietalis fascia posteriorly. They were studied using an anatomic and computed tomographic comparison. The propria fascia (lateroconal fascia) divided into the anterior and posterior layers of the perirenal fascia. The fascias delimitate two anterior and posterior pararenal spaces around the kidney compartment and two anterior and posterior perirenal spaces in the compartment itself. These spaces extended above and below the renal compartment from the diaphragm to the pelvis. These large spaces composed of fat and organs can assume the guided migration of pathologic processes or their spread according to the importance of the fascias barriers. They below to the genito-urinary region. The extraperitoneal spaces are related anteriorly to the retroperitoneal alimentary organs: duodenum, pancreas, ascending and descending colon depending of the alimentary region. They are related posteriorly with the abdominal wall and its own fat. The individuality and the interdependance of these three territories (alimentary, genito-urinary and abdominal wall) and their consequences for pathologic CT scan imaging will be discussed in the second part of this paper.

[Retroperitoneal gas images following subperitoneal hollow viscus rupture (author's transl)]. / Images de rétropneumopéritoine dans les ruptures d'organes creux sous-péritonéaux.

Three cases of traumatic rupture of a subperitoneal hollow viscus are reported : two duodenal lesions and one rectal wound. Early diagnosis was possible in all three cases by the recognition of retroperitoneal gas on simple radiographs of the abdomen, which was evidenced by images containing air bubbles, which were also fasciculated and fairly fixed. They were unilateral, on the right side, and usually associated with disappearance of the psoas shadow in duodenal injuries. Rectal perforation produces a bilateral distribution of the retroperitoneal gas, which extends to the subperitoneal fat and the posterior extraperitoneal space, according to the amount of effusion.

[Angiographic exploration of a case of a case of adrenal APUD adenoma secreting three hormones: VIP, catecholamines, and somatostatin (author's transl)]. / Exploration angiographique d'un cas d'apudome surrénalien á triple composante hormonale. VIP--catécholamines--stomatostatine.

An APUD adenoma of the right adrenal was discovered in an adult after angiography and compted tomography The tumor had provoked a WDHH syndrome. Selective venous sampling before operation demostrated the presence in the tumor of hormonal secretions (VIP and catecholamines). The patient recovered after excision of the tumor, which contained large quantities of intracellular somatostatin and VIP.