Potentiel des liposomes pour l'injection intravitréenne de molécules thérapeutiques [Potential of liposomes for the intravitreal injection of therapeutic molecules].

Intravitreal administration has been widely used since 20 years and has been shown to improve the treatment of diseases of the posterior segment of the eye with infectious origin or in edematous maculopathies. This route of administration allows to achieve high concentration of drug in the vitreous and avoids the problems resulting from systemic administration. However, two basic problems limit the use of intravitreal therapy. Many drugs are rapidly cleared from the vitreous humor; therefore, to reach and to maintain effective therapy repeated injections are necessary. Repeated intravitreal injections increase the risk of endophthalmitis, damage to lens, retinal detachment. Moreover, some drugs provoke a local toxicity at their effective dose inducing side-effects and possible retinal lesions. In this context, the development and the use of new drug delivery systems for intravitreal administration are necessary to treat chronic ocular diseases. Among them, particulate systems such as liposomes have been widely studied. Liposomes are easily injectable and permit to reduce the toxicity and to increase the residence time of several drugs in the eye. They are also able to protect in vivo poorly-stable molecules from degradation such as peptides and nucleic acids. Some promising results have been obtained for the treatment of retinitis induced by cytomegalovirus in human and more recently for the treatment of uveitis in animal. Finally, the fate of liposomes in ocular tissues and fluids after their injection into the vitreous and their elimination routes begin to be more known.

Two's company, three's a crowd: experimental evaluation of the evolutionary maintenance of trioecy in Mercurialis annua (Euphorbiaceae).

Trioecy is an uncommon sexual system in which males, females, and hermaphrodites co-occur as three clearly different gender classes. The evolutionary stability of trioecy is unclear, but would depend on factors such as hermaphroditic sex allocation and rates of outcrossing vs. selfing. Here, trioecious populations of Mercurialis annua are described for the first time. We examined the frequencies of females, males and hermaphrodites across ten natural populations and evaluated the association between the frequency of females and plant densities. Previous studies have shown that selfing rates in this species are density-dependent and are reduced in the presence of males, which produce substantially more pollen than hermaphrodites. Accordingly, we examined the evolutionary stability of trioecy using an experiment in which we (a) indirectly manipulated selfing rates by altering plant densities and the frequency of males in a fully factorial manner across 20 experimental plots and (b) examined the effect of these manipulations on the frequency of the three sex phenotypes in the next generation of plants. In the parental generation, we measured the seed and pollen allocations of hermaphrodites and compared them with allocations by unisexual plants. In natural populations, females occurred at higher frequencies in denser patches, a finding consistent with our expectations. Under our experimental conditions, however, no combination of plant densities and male frequencies was associated with increased frequencies of females. Our results suggest that the factors that regulate female frequencies in trioecious populations of M. annua are independent of those regulating male frequencies (density), and that the stable co-existence of all three sex phenotypes within populations is unlikely.

Transanal endoscopic microsurgery resection of rectal tumors: outcomes and recommendations.

PURPOSE: Transanal endoscopic microsurgery provides a minimally invasive alternative to radical surgery for excision of benign and malignant rectal tumors. The purpose of this study was to review our experience with transanal endoscopic microsurgery to clarify its role in the treatment of different types of rectal pathology. METHODS: A prospective database documented all patients undergoing transanal endoscopic microsurgery from October 1996 through June 2008. We analyzed patient and operative factors, complications, and tumor recurrence. For recurrence analysis, we excluded patients with fewer than 6 months of follow-up, previous excisions, known metastases at initial presentation, and those who underwent immediate radical resection following transanal endoscopic microsurgery. RESULTS: Two hundred sixty-nine patients underwent transanal endoscopic microsurgery for benign (n = 158) and malignant (n = 111) tumors. Procedure-related complications (21%) included urinary retention (10.8%), fecal incontinence (4.1%), fever (3.8%), suture line dehiscence (1.5%), and bleeding (1.5%). Local recurrence rates for 121 benign and 83 malignant tumors were 5% for adenomas, 9.8% for T1 adenocarcinoma, 23.5% for T2 adenocarcinoma, 100% for T3 adenocarcinoma, and 0% for carcinoid tumors. All 6 (100%) recurrent adenomas were retreated with endoscopic techniques, and 8 of 17 (47%) recurrent adenocarcinomas underwent salvage procedures with curative intent. CONCLUSIONS: Transanal endoscopic microsurgery is a safe and effective method for excision of benign and malignant rectal tumors. Transanal endoscopic microsurgery can be offered for (1) curative resection of benign tumors, carcinoid tumors, and select T1 adenocarcinomas, (2) histopathologic staging in indeterminate cases, and (3) palliative resection in patients medically unfit or unwilling to undergo radical resection.

Cardenolides, induced responses, and interactions between above- and belowground herbivores of milkweed (Asclepias spp.).

Theory has long predicted allocation patterns for plant defense against herbivory, but only recently have both above- and belowground plant defenses been considered simultaneously. Milkweeds in the genus Asclepias are a classic chemically defended clade of plants with toxic cardenolides (cardiac glycosides) and pressurized latex employed as anti-herbivore weapons. Here we combine a comparative approach to investigate broadscale patterns in allocation to root vs. shoot defenses across species with a species-specific experimental approach to identify the consequences of defense allocational shifts on a specialist herbivore. Our results show phylogenetic conservatism for inducibility of shoot cardenolides by an aboveground herbivore, with only four closely related tropical species showing significant induction; the eight temperate species examined were not inducible. Allocation to root and shoot cardenolides was positively correlated across species, and this relationship was maintained after accounting for phylogenetic nonindependence. In contrast to long-standing theoretical predictions, we found no evidence for a trade-off between constitutive and induced cardenolides; indeed the two were positively correlated across species in both roots and shoots. Finally, specialist root and shoot herbivores of common milkweed (A. syriaca) had opposing effects on latex production, and these effects had consequences for caterpillar growth consistent with latex providing resistance. Although cardenolides were not affected by our treatments, A. syriaca allocated 40% more cardenolides to shoots over roots. We conclude that constitutive and inducible defenses are not trading off across plant species, and shoots of Asclepias are more inducible than roots. Phylogenetic conservatism cannot explain the observed patterns of cardenolide levels across species, but inducibility per se was conserved in a tropical clade. Finally, given that above- and belowground herbivores can systemically alter the defensive phenotype of plants, we concur with recent calls for a whole-plant perspective in testing models of plant defense allocation.

Allergen-induced IgE-dependent gut inflammation in a human PBMC-engrafted murine model of allergy.

BACKGROUND: Humanized murine models comprise a new tool to analyze novel therapeutic strategies for allergic diseases of the intestine.¦OBJECTIVE: In this study we developed a human PBMC-engrafted murine model of allergen-driven gut inflammation and analyzed the underlying immunologic mechanisms.¦METHODS: Nonobese diabetic (NOD)-scid-γc(-/-) mice were injected intraperitoneally with human PBMCs from allergic donors together with the respective allergen or not. Three weeks later, mice were challenged with the allergen orally or rectally, and gut inflammation was monitored with a high-resolution video miniendoscopic system, as well as histologically.¦RESULTS: Using the aeroallergens birch or grass pollen as model allergens and, for some donors, also hazelnut allergen, we show that allergen-specific human IgE in murine sera and allergen-specific proliferation and cytokine production of human CD4(+) T cells recovered from spleens after 3 weeks could only be measured in mice treated with PBMCs plus allergen. Importantly, these mice had the highest endoscopic scores evaluating translucent structure, granularity, fibrin, vascularity, and stool after oral or rectal allergen challenge and a strong histologic inflammation of the colon. Analyzing the underlying mechanisms, we demonstrate that allergen-associated colitis was dependent on IgE, human IgE receptor-expressing effector cells, and the mediators histamine and platelet-activating factor.¦CONCLUSION: These results demonstrate that allergic gut inflammation can be induced in human PBMC-engrafted mice, allowing the investigation of pathophysiologic mechanisms of allergic diseases of the intestine and evaluation of therapeutic interventions.

Differential allocation and deployment of direct and indirect defences by Vicia sepium along elevation gradients

Dissecting drivers of plant defence investment remains central for understanding the assemblage of communities across different habitats. There is increasing evidence that direct defence strategies against herbivores, including secondary metabolites production, differ along ecological gradients in response to variation in biotic and abiotic conditions. In contrast, intraspecific variation in indirect defences remains unexplored. Here, we investigated variation in herbivory rate, resistance to herbivores, and indirect defences in ant-attracting Vicia species along the elevation gradient of the Alps. Specifically, we compared volatile organic compounds (VOCs) and ant attraction in high and low elevation ecotypes. Consistent with adaptation to the lower herbivory conditions that we detected at higher elevations in the field, high elevation plants were visited by fewer ants and were more susceptible to herbivore attack. In parallel, constitutive volatile organic compound production and subsequent ant attraction were lower in the high elevation ecotypes. We observed an elevation-driven trade-off between constitutive and inducible production of VOCs and ant attraction along the environmental cline. At higher elevations, inducible defences increased, while constitutive defence decreased, suggesting that the high elevation ecotypes compensate for lower indirect constitutive defences only after herbivore attack. Synthesis. Overall, direct and indirect defences of plants vary along elevation gradients. Our findings show that plant allocation to defences are subject to trade-offs depending on local conditions, and point to a feedback mechanism linking local herbivore pressure, predator abundance and the defence investment of plants.

Sudden cardiac death in the young (5-39 years) in the canton of Vaud, Switzerland.

BACKGROUND: Sudden cardiac death (SCD) among the young is a rare and devastating event, but its exact incidence in many countries remains unknown. An autopsy is recommended in every case because some of the cardiac pathologies may have a genetic origin, which can have an impact on the living family members. The aims of this retrospective study completed in the canton of Vaud, Switzerland were to determine both the incidence of SCD and the autopsy rate for individuals from 5 to 39 years of age. METHODS: The study was conducted from 2000 to 2007 on the basis of official statistics and analysis of the International Classification of Diseases codes for potential SCDs and other deaths that might have been due to cardiac disease. RESULTS: During the 8 year study period there was an average of 292'546 persons aged 5-39 and there were a total of 1122 deaths, certified as potential SCDs in 3.6% of cases. The calculated incidence is 1.71/100'000 person-years (2.73 for men and 0.69 for women). If all possible cases of SCD (unexplained deaths, drowning, traffic accidents, etc.) are included, the incidence increases to 13.67/100'000 person-years. However, the quality of the officially available data was insufficient to provide an accurate incidence of SCD as well as autopsy rates. The presumed autopsy rate of sudden deaths classified as diseases of the circulatory system is 47.5%. For deaths of unknown cause (11.1% of the deaths), the autopsy was conducted in 13.7% of the cases according to codified data. CONCLUSIONS: The incidence of presumed SCD in the canton of Vaud, Switzerland, is comparable to the data published in the literature for other geographic regions but may be underestimated as it does not take into account other potential SCDs, as unexplained deaths. Increasing the autopsy rate of SCD in the young, better management of information obtained from autopsies as well developing of structured registry could improve the reliability of the statistical data, optimize the diagnostic procedures, and the preventive measures for the family members.

Location Determinants of New Firms: Does Skill Level of Human Capital Really Matter?

This paper is about the role played by stock of human capital on location decisions of new manufacturing plants. We analyse the effect of several skill levels (from basic school to PhD) on decisions about the location of plants in various industries and, therefore, of different technological levels. We also test whether spatial aggregation level biases the results and determine the most appropriate areas to be considered in analyses of these phenomena. Our main statistical source is the Register of Manufacturing Establishments of Catalonia (REIC), which has plant-level microdata on the locations of new manufacturing plants. Keywords: agglomeration economies, industrial location, human capital, count-data models, spatial econometrics.

MAP kinase pathways in UV-induced apoptosis of retinal pigment epithelium ARPE19 cells.

The retinal pigment epithelium (RPE) is constantly exposed to external injuries which lead to degeneration, dysfunction or loss of RPE cells. The balance between RPE cells death and proliferation may be responsible for several diseases of the underlying retina, including age-related macular degeneration (AMD) and proliferative vitreoretinopathy (PVR). Signaling pathways able to control cells proliferation or death usually involve the MAPK (mitogen-activated protein kinases) pathways, which modulate the activity of transcription factors by phosphorylation. UV exposure induces DNA breakdown and causes cellular damage through the production of reactive oxygen species (ROS) leading to programmed cell death. In this study, human retinal pigment epithelial cells ARPE19 were exposed to 100 J/m(2) of UV-C and MAPK pathways were studied. We first showed the expression of the three major MAPK pathways. Then we showed that activator protein-1 (AP-1) was activated through phosphorylation of cJun and cFos, induced by JNK and p38, respectively. Specific inhibitors of both kinases decreased their respective activities and phosphorylation of their nuclear targets (cJun and cFos) and reduced UV-induced cell death. The use of specific kinases inhibitors may provide excellent tools to prevent RPE apoptosis specifically in RPE diseases involving ROS and other stress-related compounds such as in AMD.

Reconstructing the origins of high-alpine niches and cushion life form in the genus Androsace S.L. (Primulaceae).

Relatively, few species have been able to colonize extremely cold alpine environments. We investigate the role played by the cushion life form in the evolution of climatic niches in the plant genus Androsace s.l., which spreads across the mountain ranges of the Northern Hemisphere. Using robust methods that account for phylogenetic uncertainty, intraspecific variability of climatic requirements and different life-history evolution scenarios, we show that climatic niches of Androsace s.l. exhibit low phylogenetic signal and that they evolved relatively recently and punctually. Models of niche evolution fitted onto phylogenies show that the cushion life form has been a key innovation providing the opportunity to occupy extremely cold environments, thus contributing to rapid climatic niche diversification in the genus Androsace s.l. We then propose a plausible scenario for the adaptation of plants to alpine habitats.

The Bernhard Nocht Institute: 100 years of tropical medicine in Hamburg

The Bernhard Nocht Institute (BNI) is a four months younger and much smaller sibling of the Instituto Oswaldo Cruz. It was founded on 1 October 1900 as an Institut für Schiffs- und Tropenkrankheiten (Institute for Maritime and Tropical Diseases) and was later named after its founder and first director Bernhard Nocht. Today it is the Germany's largest institution for research in tropical medicine. It is a government institution affiliated to the Federal Ministry of Health of Germany and the Department of Health of the State of Hamburg. As the center for research in tropical medicine in Germany the BNI is dedicated to research, training and patient care in the area of human infectious diseases, which are of particular relevance in the tropics. It is the primary mission of the BNI to develop means to the control of these diseases. Secondary missions are to provide expertise for regional and national authorities and to directly and indirectly improve the health care for national and regional citizens in regard to diseases of the tropics.

Pursestring closure of the stoma site leads to fewer wound infections: results from a multicenter randomized controlled trial.

BACKGROUND: Surgical site infection after stoma reversal is common. The optimal skin closure technique after stoma reversal has been widely debated in the literature. OBJECTIVE: We hypothesized that pursestring near-complete closure of the stoma site would lead to fewer surgical site infections compared with conventional primary closure. DESIGN: This study was a parallel prospective multicenter randomized controlled trial. SETTINGS: This study was conducted at 2 university medical centers. PATIENTS: Patients (N = 122) presenting for elective colostomy or ileostomy reversal were selected. INTERVENTIONS: Pursestring versus conventional primary closure of stoma sites were compared. MAIN OUTCOME MEASURES: Stoma site surgical site infection within 30 days of surgery, overall surgical site infection, delayed healing (open wound for >30 days), time to wound epithelialization, and patient satisfaction were the primary outcomes measured. RESULTS: The pursestring group had a significantly lower stoma site infection rate (2% vs 15%, p = 0.01). There was no difference in delayed healing or patient satisfaction between groups. Time to epithelialization was measured in only 51 patients but was significantly longer in the pursestring group (34.6 ± 20 days vs 24.1 ± 17 days, p = 0.02). LIMITATIONS: This study was limited by the variability in procedures and surgeons, the limited follow-up after 30 days, and the inability to perform blinding. CONCLUSION: Pursestring closure after stoma reversal has a lower risk of stoma site surgical site infection than conventional primary closure, although wounds may take longer to heal with the use of this approach. REGISTRATION NUMBER: NCT01713452 (www.clinicaltrials.gov).

Chagas disease: current epidemiological trends after the interruption of vectorial and transfusional transmission in the Southern Cone countries

Chagas disease, named after Carlos Chagas who first described it in 1909, exists only on the American Continent. It is caused by a parasite, Trypanosoma cruzi, transmitted to humans by blood-sucking triatomine bugs and by blood transfusion. Chagas disease has two successive phases, acute and chronic. The acute phase lasts 6 to 8 weeks. After several years of starting the chronic phase, 20% to 35% of the infected individuals, depending on the geographical area will develop irreversible lesions of the autonomous nervous system in the heart, esophagus, colon and the peripheral nervous system. Data on the prevalence and distribution of Chagas disease improved in quality during the 1980's as a result of the demographically representative cross-sectional studies carried out in countries where accurate information was not available. A group of experts met in Brasília in 1979 and devised standard protocols to carry out countrywide prevalence studies on human T. cruzi infection and triatomine house infestation. Thanks to a coordinated multi-country program in the Southern Cone countries the transmission of Chagas disease by vectors and by blood transfusion has been interrupted in Uruguay in1997, in Chile in 1999, and in 8 of the 12 endemic states of Brazil in 2000 and so the incidence of new infections by T. cruzi in the whole continent has decreased by 70%. Similar control multi-country initiatives have been launched in the Andean countries and in Central America and rapid progress has been recorded to ensure the interruption of the transmission of Chagas disease by 2005 as requested by a Resolution of the World Health Assembly approved in 1998. The cost-benefit analysis of the investments of the vector control program in Brazil indicate that there are savings of US$17 in medical care and disabilities for each dollar spent on prevention, showing that the program is a health investment with good return. Since the inception in 1979 of the Steering Committee on Chagas Disease of the Special Program for Research and Training in Tropical Diseases of the World Health Organization (TDR), the objective was set to promote and finance research aimed at the development of new methods and tools to control this disease. The well known research institutions in Latin America were the key elements of a world wide network of laboratories that received - on a competitive basis - financial support for projects in line with the priorities established. It is presented the time line of the different milestones that were answering successively and logically the outstanding scientific questions identified by the Scientific Working Group in 1978 and that influenced the development and industrial production of practical solutions for diagnosis of the infection and disease control.

Trypanocidal activity of Meliaceae and Rutaceae plant extracts

The in vitro trypanocidal activity of 22 extracts and 43 fractions of plants belonging to the families Meliaceae and Rutaceae was evaluated. The extracts from leaves of Conchocarphus heterophyllus and branches of Trichilia ramalhoi were the most active. The trypanocidal activity seems to be increased by fractionation of the extracts. Fractions from C. heterophyllus and Galipea carinata were the most active and a 100% lysis of the parasites was observed for five fractions. From one of them were isolated two flavonoids: flavone and 7-methoxyflavone, which showed weak trypanocidal activity. The results obtained from the extracts and fractions revealed that the order Rutales is a promising source for the search of new drugs for Chagas disease. Phytochemical studies with the other active fractions are underway in order to isolate compounds, which could be associated with observed activities.

The glycoinositol-phospholipids of Phytomonas.

The Phytomonas spp. are trypanosomatid parasites of plants. A polar glycolipid fraction of a Phytomonas sp., isolated from the plant Euphorbia characias and grown in culture, was fractionated into four major glycolipid species (Phy 1-4). The glycolipids were analysed by chemical and enzymic modifications, composition and methylation analyses, electrospray mass spectrometry and microsequencing after HNO2 deamination and NaB3H4 reduction. The water-soluble headgroup of the Phy2 glycolipid was also analysed by 1H NMR. All four glycolipids were shown to be glycoinositol-phospholipids (GIPLs) with phosphatidylinositol (PI) moieties containing the fully saturated alkylacylglycerol lipids 1-O-hexadecyl-2-O-palmitoylglycerol and 1-O-hexadecyl-2-O-stearoylglycerol. The structures of the Phy 1-4 GIPLs are: Man alpha 1-2Man alpha 1-6Man alpha 1-4GlcN alpha 1-6PI, Glc alpha 1-2(NH2-CH2CH2-HPO4-)Man alpha 1-2Man alpha 1-6Man alpha 1-4GlcN alpha 1-6PI, [formula: see text] Glc alpha 1-2(NH2CH2CH2-HPO4-)Man alpha 1-2Man alpha 1-6Man alpha 1-4(NH2-CH2CH2-HPO4-)GlcN alpha 1-6PI [formula: see text] and Glc alpha 1-2Glc alpha 1-2(NH2CH2-CH2-HPO4-)Man alpha 1-2Man alpha 1-6Man alpha 1-4(NH2CH2CH2-HPO4-)-GlcN alpha 1-6PI. [formula: see text] The Phytomonas GIPLs represent a novel series of structures. This is the first description of the chemical structure of cell-surface molecules of this plant pathogen. The Phytomonas GIPLs are compared with those of other trypanosomatid parasites and are discussed with respect to trypanosomatid phylogenetic relationships.