970 resultados para Complete Tripartite Graph 5-cycle


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Eosinophils have long been thought to be effectors of immunity to helminths but have also been implicated in the pathogenesis of asthma. Patterns of cytokine production in the host may influence the pathogenesis of these diseases by regulating the activities of eosinophils and other components of the immune response. Mice which constitutively over-express IL-5 have profound and life-long eosinophilia in a restricted number of tissues. Although eosinophils from IL-5 transgenics are functionally competent for a number of parameters considered to be important in inflammation, untreated animals are overtly normal and free of disease. In addition, the responses of these animals when exposed to aeroallergens and helminths present a number of apparent paradoxes. Eosinophil accumulation in tissues adjacent to major airways is rapid and extensive in transgenics exposed to the aeroallergen, but even after treatment with antigen over many months these mice show no evidence of respiratory distress or pathology. Helminth-infected IL-5 transgenics and their non-transgenic littermates develop similar inflammatory responses at mucosal sites and are comparable for a number of T cell and antibody responses, but they differ considerably in their ability to clear some parasite species. The life-cycle of Nippostrongylus brasiliensis is significantly inhibited in IL-5 transgenics, but that of Toxocara canis is not. Our results also suggest that eosinophilia and/or over-expression of IL-5 may actually impair host resistance to Schistosoma mansoni and Trichinella spiralis. The pathogenesis of diseases in which eosinophils are involved may therefore be more complex than previously thought.

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We use a dynamic factor model to provide a semi-structural representation for 101 quarterly US macroeconomic series. We find that (i) the US economy is well described by a number of structural shocks between two and six. Focusing on the four-shock specification, we identify, using sign restrictions, two non-policy shocks, demand and supply, and two policy shocks, monetary and fiscal. We obtain the following results. (ii) Both supply and demand shocks are important sources of fluctuations; supply prevails for GDP, while demand prevails for employment and inflation. (ii) Policy matters, Both monetary and fiscal policy shocks have sizeable effects on output and prices, with little evidence of crowding out; both monetary and fiscal authorities implement important systematic countercyclical policies reacting to demand shocks. (iii) Negative demand shocks have a large long-run positive effect on productivity, consistently with the Schumpeterian "cleansing" view of recessions.

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The life cycle of Lutzomyia shannoni (Dyar), was described for laboratory conditions with maximum daily temperatures of 27-30°C, minimum daily temperatures of 22-27°C and relative humidity between 87-99 %. Life cycle in each stage was as follows: egg 6-12 days (ave. 8.5 days); first stage larva 5-13 days (ave. 9.6 days); second stage larva 4-13 days (ave. 9.2 days ); third stage larva 5-19 days (ave. 11.8 days); fourth stage larva 7-37 days (ave. 19.9 days); pupa 7-32 days (ave. 15.2 days). The life expectancy of adults ranged from 4 to 15 days (ave. 8.6 days). The entire egg to adult period ranged from 36 to 74 days (ave. 54.6 days). On average, each female oviposited 22.7 eggs; the average egg retention per female was 24.3 eggs.

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The life cycle and reproductive patterns of Triatoma rubrofasciata were studied along with laboratory conditions for the establishment of a prolific colony. The insects were divided into four groups: two of them were maintained at room temperature (20.5°C to 33°C and 85% ± 5% of relative humidity), the other two in a climatic chamber (CC) (temperature: 29°C, humidity: 80% ± 5%). The groups were fed weekly or fortnightly on Swiss mice. The females from the group kept in the CC and fed weekly had longer life span, as well as a higher number of eggs, fertile eggs and hatchings; the group kept in the CC and fed fortnightly had a shorter life span for the 1st, 2nd and 3rd instars and a lower mortality rate for all instars. It was concluded that a constant high temperature (CC at 29°C) is the most suitable condition for the maintenance of a colony of T. rubrofasciata regardless of the interval between repasts.

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BACKGROUND: Copeptin, a surrogate marker for arginin vasopressin production, is evaluated as an osmo-dependent stress and inflammatory biomarker in different diseases. We investigated copeptin during the menstrual cycle and its relationship to sex hormones, markers of subclinical inflammation and estimates of body fluid. METHODS: In 15 healthy women with regular menstrual cycles, blood was drawn on fifteen defined days of their menstrual cycle and was assayed for copeptin, progesterone, estradiol, luteinizing hormone, high-sensitive C-reactive protein, tumor necrosis factor-alpha and procalcitonin. Symptoms of fluid retention were assessed on each visit, and bio impedance analysis was measured thrice to estimate body fluid changes. Mixed linear model analysis was performed to assess the changes of copeptin across the menstrual cycle and the relationship of sex hormones, markers of subclinical inflammation and estimates of body fluid with copeptin. RESULTS: Copeptin levels did not significantly change during the menstrual cycle (p = 0.16). Throughout the menstrual cycle, changes in estradiol (p = 0.002) and in the physical premenstrual symptom score (p = 0.01) were positively related to copeptin, but changes in other sex hormones, in markers of subclinical inflammation or in bio impedance analysis-estimated body fluid were not (all p = ns). CONCLUSION: Although changes in estradiol and the physical premenstrual symptom score appear to be related to copeptin changes, copeptin does not significantly change during the menstrual cycle.

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Polyomavirus JC (JCV) is ubiquitous in humans and causes a chronic demyelinating disease of the central nervous system , progressive multifocal leukoencephalopathy which is common in AIDS. JCV is excreted in urine of 30-70% of adults worldwide. Based on sequence analysis of JCV complete genomes or fragments thereof, JCV can be classified into geographically derived genotypes. Types 1 and 2 are of European and Asian origin respectively while Types 3 and 6 are African in origin. Type 4, a possible recombinant of European and African genotypes (1 and 3) is common in the USA. To delineate the JCV genotypes in an aboriginal African population, random urine samples were collected from the Biaka Pygmies and Bantu from the Central African Republic. There were 43 males and 25 females aged 4-55 years, with an average age of 26 years. After PCR amplification of JCV in urine, products were directly cycle sequenced. Five of 23 Pygmy adults (22%) and four of 20 Bantu adults (20%) were positive for JC viruria. DNA sequence analysis revealed JCV Type 3 (two), Type 6 (two) and one Type 1 variant in Biaka Pygmies. All the Bantu strains were Type 6. Type 3 and 6 strains of JCV are the predominant strains in central Africa. The presence of multiple subtypes of JCV in Biaka Pygmies may be a result of extensive interactions of Pygmies with their African tribal neighbors during their itinerant movements in the equatorial forest.

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The type three secretion system (T3SS) operons of Chlamydiales bacteria are distributed in different clusters along their chromosomes and are conserved at both the level of sequence and genetic organization. A complete characterization of the temporal expression of multiple T3SS components at the transcriptional and protein levels has been performed in Parachlamydia acanthamoebae, replicating in its natural host cell Acanthamoeba castellanii. The T3SS components were classified in four different temporal clusters depending on their pattern of expression during the early, mid- and late phases of the infectious cycle. The putative T3SS transcription units predicted in Parachlamydia are similar to those described in Chlamydia trachomatis, suggesting that T3SS units of transcriptional expression are highly conserved among Chlamydiales bacteria. The maximal expression and activation of the T3SS of Parachlamydia occurred during the early to mid-phase of the infectious cycle corresponding to a critical phase during which the intracellular bacterium has (1) to evade and/or block the lytic pathway of the amoeba, (2) to differentiate from elementary bodies (EBs) to reticulate bodies (RBs), and (3) to modulate the maturation of its vacuole to create a replicative niche able to sustain efficient bacterial growth.

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The Great Tohoku-Kanto earthquake and resulting tsunami has brought considerable attention to the issue of the construction of new power plants. We argue in this paper, nuclear power is not a sustainable solution to energy problems. First, we explore the stock of uranium-235 and the different schemes developed by the nuclear power industry to exploit this resource. Second, we show that these methods, fast breeder and MOX fuel reactors, are not feasible. Third, we show that the argument that nuclear energy can be used to reduce CO2 emissions is false: the emissions from the increased water evaporation from nuclear power generation must be accounted for. In the case of Japan, water from nuclear power plants is drained into the surrounding sea, raising the water temperature which has an adverse affect on the immediate ecosystem, as well as increasing CO2 emissions from increased water evaporation from the sea. Next, a short exercise is used to show that nuclear power is not even needed to meet consumer demand in Japan. Such an exercise should be performed for any country considering the construction of additional nuclear power plants. Lastly, the paper is concluded with a discussion of the implications of our findings.

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The intermediate host of Fasciola hepatica, Lymnaea columella, collected in Belo Horizonte, Minas Gerais, Brazil, was reared in our laboratory. The aim of the current study was to standardize a rearing and maintenance technique. Two kinds of diet were tested: fresh lettuce (A) and rodent ration + 10% CaCO3 plus fresh lettuce (B). The age for the beginning of oviposition ranged from 27 to 57 days. Ten days after oviposition at 24.7°C, 100% eclosion occurred. The complete life cycle varied from 37 to 67 days. The average numbers of eggs per egg mass were 26.3 and 31.1 with diets (A) and (B), respectively. The lettuce and ration fed snails presented a increased growth although the difference was not statistically significant (p > 0.05). The mortality rate varied from 40 to 64% after 90 days. The maximum longevity was 183 days, 21.5 mm length and 11 mm wide. The methodology to mass breed and maintain these snails was found to be suitable in the laboratory

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The life cycle of Clerada apicicornis was determined under laboratory conditions. Mean development times in days were: egg 27.2, nymph I 12.5, nymph II 12, nymph III 13.4, nymph IV 16.4, nymph V 26. The life expectancy of adults ranged from 117 to 317 days (mean 196 days). Based on a cohort of 29 females of C. apicicornis, a horizontal life table was constructed. The following predictive parameters were obtained: net rate of reproduction (Ro = 48.31), intrinsic rate of population increase (r m = 0.153), generation time (Tc = 28.20 weeks), and finite rate of population increment (lambda = 1.16). The reproductive value (Vx) for each age class of the cohort females was calculated. The following observed parameters were calculated after mortality in each stage: net rate of reproduction (R'o=13.4), intrinsic rate of population increase (r c' =0.09 ), and finite rate of population increment (lambda' =1.1). The generation time (Tc' =27.4) was estimated using the methods of Laughlin and Bengstron. A vertical life table was elaborated and mortality was described for one generation of the cohort.

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The complete life cycle of Triatoma flavida, weekly fed on hens, was studied at 28±2°C and 80±10% RH. Aspects related to hatching, life span, mortality and feeding behavior for each stage of its life cycle were evaluated. The hatching rate observed for 100 eggs was 93% with an average incubation period of 27.2 days. Sixty-two nymphs completed the cycle and the mean egg to adult development time was 230.4 days. Mean duration of 1st, 2nd, 3rd, 4th and 5th instar nymphs was 22.1, 25.3, 36.7, 49.7 and 69.4 days, respectively. The number of blood meals on each nymphal stage varied from 1 to 7. The mortality rate was 6.5% for NI, 23% for NIII and 7.5% for NV nymphs. Mean number of laid eggs per female was 283.1. Adult survival rates were 344.8 ± 256.4 days for males and 285.3 ± 201.8 days for females.

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Although a disease of great antiquity, scientific studies of schistosomiasis began only 150 years ago. The complete life-cycle was not described until just before the First World War, making it possible at last to plan proper community control programmes. Inadequate tools prevented their effective implementation until well after the Second World War when new tools became available, thanks to the newly formed World Health Organization. Molluscicides spearheaded control programmes until the late 1970s but were then replaced by the newly developed, safe drugs still used today. Whatever the method used, the initial goal of eradication was, in the light of experience and cost, gradually replaced by less ambitious targets; first to stop transmission and then to reduce morbidity. The most successful programmes combined several methods to minimise reinfection after chemotherapy. Comparisons between different programmes are difficult without using appropriate, standardised diagnostic techniques and the correct epidemiological measurements. Some examples will be presented, mainly from our studies on Schistosoma mansoni in Kenya. Drug resistance on a scale comparable with malaria has not occurred in schistosomiasis but the likely withdrawal of all drugs except praziquantel leaves its control extremely vulnerable to this potential problem. An effective, affordable vaccine for use in endemic countries is unlikely to be ready for at least 5 years, and developing strategies for its use could take a further decade or more, judging from experience with drugs and molluscicides. In the interim, by analogy with malaria, the most cost-effective approach would the use of drugs combined with other methods to stop transmission, including molluscicides. The cost of molluscicides needs to be reduced and fears allayed about their supposedly adverse ecological effects.

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Fascioliasis is a parasitic disease of domestic ruminants that occurs worldwide. The lymnaeid intermediate hosts of Fasciola hepatica include Lymnaea columella, which is widely distributed in Brazil. A colony of L. columella from Belo Horizonte, MG, was reared in our laboratory to be used in studies of the F. hepatica life cycle, the intermediate host-parasite relationship and development of an anti-helminthic vaccine. In the first experiment 1,180 snails were exposed to miracidia of F. hepatica eggs removed from the biliary tracts of cattle from the State of Rio Grande do Sul. In the second and third experiments the snails were exposed to miracidia that had emerged from F. hepatica eggs from Uruguay, maintained in rabbits. The rates of infection in the first, second and third experiments were 0, 42.1 and 0% respectively. Over 15,806 metacercariae were obtained and stored at 4ºC. Four rabbits weighing 1.5 kg each were infected with 32-44 metacercariae and two with 200. Three rabbits begin to eliminate eggs of the parasite in the feces from 84 days after infection onwards. The biological cycle of F. hepatica in L. columella and the rabbit was completed within 124 days.

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La majorité des organelles d'une cellule adaptent leur nombre et leur taille pendant les processus de division cellulaire, de trafic vésiculaire ou suite à des changements environnementaux par des processus de fusion et de fragmentation membranaires. Ceci est valable notamment pour le golgi, les mitochondries, les péroxisomes et les lysosomes. La vacuole est le compartiment terminal de la voie endocytaire dans la levure Saccharomyces cerevisiae\ elle correspond aux lysosomes des cellules mammifères. Suite à un choc hyperosmotique, la vacuole se fragmente en plusieurs petites vésicules. Durant ce projet, cette fragmentation a été étudiée en utilisant la technique de microscopie confocale in vivo. J'ai observé que la division de la vacuole se produit d'une façon asymétrique. La première minute après le choc osmotique, les vacuoles rétrécissent et forment des longues invaginations tubulaires. Cette phase est dépendante de la protéine Vps1, un membre de la famille des protéines apparentées à la dynamine, ainsi que d'un gradient transmembranaire de protons. Pendant les 10-15 minutes qui suivent, des vésicules se détachent dans les régions où l'on observe les invaginations pendant la phase initiale. Cette deuxième phase qui mène à la fission des nouveaux compartiments vacuolaires dépend de la production du lipide PI(3,5)P2 par la protéine Fab1. J'ai établi la suite des événements du processus de fragmentation des vacuoles et propose la possibilité d'un rôle régulateur de la protéine kinase cycline-dépendante Pho85.¦En outre, j'ai tenté d'éclaircir plus spécifiquement le rôle de Vps1 pendant la fusion et fission des vacuoles. J'ai trouvé que tous les deux processus sont dépendants de l'activité GTPase de cette protéine. De plus l'association avec la membrane vacuolaire paraît régulée par le cycle d'hydrolyse du GTP. Vps1 peut lier la membrane sans la présence d'un autre facteur protéinique, ce qui permet de conclure à une interaction directe avec des lipides de la membrane. Cette interaction est au moins partiellement effectuée par le domaine GTPase, ce qui est une nouveauté pour un membre de cette famille de protéines. Une deuxième partie de Vps1, nommée insert B, est impliquée dans la liaison à la vacuole, soit par interaction directe avec la membrane, soit par régulation du domaine GTPase. En assumant que Vps1 détienne deux régions capables de liaison aux membranes, je conclus qu'elle pourrait fonctionner comme facteur de « tethering » lors de la fusion des vacuoles.¦-¦La cellule contient plusieurs sous-unités, appelées organelles, possédant chacune une fonction spécifique. Dépendant des processus qui s'y déroulent à l'intérieur, un environnement chimique spécifique est requis. Pour maintenir ces différentes conditions, les organelles sont séparées par des membranes. Lors de la division cellulaire ou en adaptation à des changements de milieu, les organelles doivent être capables de modifier leur morphologie. Cette adaptation a souvent lieu par fusion ou division des organelles. Le même principe est valable pour la vacuole dans la levure. La vacuole est une organelle qui sert principalement au stockage des aliments et à la dégradation des différents composants cellulaires. Alors que la fusion des vacuoles est un processus déjà bien décrit, la fragmentation des vacuoles a jusqu'ici été peu étudiée. Elle peut être induit par un choc osmotique: à cause de la concentration de sel élevé dans le milieu, le cytosol de la levure perd de l'eau. Par un flux d'eau de la vacuole au cytosol, la cellule est capable d'équilibrer celui-ci. Quand la vacuole perd du volume, elle doit réadapter le rapport entre surface membranaire et volume, ce qui se fait efficacement par une fragmentation d'une grande vacuole en plusieurs petites vésicules. Comment ce processus se déroule d'un point de vue morphologique n'a pas été décrit jusqu'à présent. En analysant la fragmentation vacuolaire par microscopie, j'ai trouvé que celle-ci se déroule en deux phases. Pendant la première minute suivant le choc osmotique, les vacuoles rétrécissent et forment des longues invaginations tubulaires. Cette phase dépend de la protéine Vps1, un membre de la famille des protéines apparentées à la dynamine, ainsi que du gradient transmembranaire de protons. Ce gradient s'établit par une pompe membranaire, la V-ATPase, qui transporte des protons dans la vacuole en utilisant l'énergie libérée par hydrolyse d'ATP. Après cette phase initiale, la formation de nouvelles vésicules vacuolaires dépend de la synthèse du lipide PI(3,5)P2.¦Dans la deuxième partie de l'étude, j'ai tenté de décrire comment Vps1 lie la membrane pour effectuer un remodelage de la vacuole. Vps1 est nécessaire pour la fusion et la fragmentation des vacuoles. J'ai découvert que tous les deux processus dépendent de sa capacité d'hydrolyser du GTP. Ainsi l'association avec la membrane est couplée au cycle d'hydrolyse du GTP. Vps1 peut lier la membrane sans la présence d'une autre protéine, et interagit donc très probablement avec les lipides de la membrane. Deux parties différentes de la protéine sont impliquées dans la liaison, dont une, inattendue, le domaine GTPase.¦-¦Numerous organelles undergo membrane fission and fusion events during cell division, vesicular traffic, or in response to changes in environmental conditions. Examples include Golgi (Acharya et al., 1998) mitochondria (Bleazard et al., 1999) peroxisomes (Kuravi et al., 2006) and lysosomes (Ward et al., 1997). In the yeast Saccharomyces cerevisiae the vacuole is the terminal component of the endocytic pathway and corresponds to lysosomes in mammalian cells. Yeast vacuoles fragment into multiple small vesicles in response to a hypertonic shock. This rapid and homogeneous reaction can serve as a model to study the requirements of the fragmentation process. Here, I investigated osmotically induced fragmentation by time-lapse microscopy. I observe that the small fragmentation products originate directly from the large central vacuole by asymmetric scission rather than by consecutive equal divisions and that fragmentation occurs in two distinct phases. During the first minute, vacuoles shrink and generate deep invaginations, leaving behind tubular structures. This phase requires the dynamin-like GTPase Vps1 and the vacuolar proton gradient. In the subsequent 10-15 minutes, vesicles pinch off from the tubular structures in a polarized fashion, directly generating fragmentation products of the final size. This phase depends on the production of phosphatidylinositol- 3,5-bisphosphate by the Fab1 complex. I suggest a possible regulation of vacuole fragmentation by the CDK Pho85. Based on my microscopy study I established a sequential involvement of the different fission factors.¦In addition to the morphological description of vacuole fragmentation I more specifically aimed to shed some light on the role of Vps1 in vacuole fragmentation and fusion. I find that both functions are dependent on the GTPase activity of the protein and that also the membrane association of the dynamin-like protein is coupled to the GTPase cycle. I found that Vps1 has the capacity for direct lipid binding on the vacuole and that this lipid binding is at least partially mediated through residues in the GTPase domain, a complete novelty for a dynamin family member. A second stretch located in the region of insert Β has also membrane-binding activity or regulates the association with the vacuole through the GTPase domain. Under the assumption of two membrane-binding regions I speculate on Vps1 as a possible tethering factor for vacuole fusion.

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BACKGROUND: Gemcitabine, oxaliplatin and 5-fluorouracil (5-FU) are active in biliary tract cancer and have a potentially synergistic mode of action and non-overlapping toxicity. The objective of these trials was to determine response, survival and toxicity separately in patients with bile duct cancer (BDC) and gallbladder cancer (GBC) treated with gemcitabine/oxaliplatin/5-FU chemotherapy. METHODS: Eligible patients with histologically proven, advanced or metastatic BDC (n=37) or GBC (n=35) were treated with gemcitabine (900 mg m(-2) over 30 min), oxaliplatin (65 mg m(-2)) and 5-FU (1500 mg m(-2) over 24 h) on days 1 and 8 of a 21-day cycle. Tumour response was the primary outcome measure. RESULTS: Response rates were 19% (95% CI: 6-32%) and 23% (95% CI: 9-37%) for BDC and GBC, respectively. Median survivals were 10.0 months (95% CI: 8.6-12.4) and 9.9 months (95% CI: 7.5-12.2) for BDC and GBC, respectively, and 1- and 2-year survival rates were 40 and 23% in BDC and 34 and 6% in GBC (intention-to-treat analysis). Major grade III and IV adverse events were neutropenia, thrombocytopenia, elevated bilirubin and anorexia. CONCLUSION: Triple-drug chemotherapy achieves comparable results for response and survival to previously reported regimens, but with more toxicity.