Hookworm infection aggravates metabolic disorder in obesity.

Obesity and ancylostomiasis are considered public health problems. Recent studies have shown that infection by intestinal helminths in obese individuals can ameliorate metabolic disorder and improve glucose tolerance by decreasing both insulin resistance and low-intensity inflammation. However, few helminth species have been studied in this context, and some modulation mechanisms still require deeper investigation. Therefore, the present work aimed to investigate the role of experimental infection with Ancylostoma ceylanicum in the modulation of the immune response in an obese experimental model. Four groups of hamsters were used as follows: two groups were submitted to a hyperlipidic and hypercaloric diet capable of inducing obesity, one infected and the other uninfected; and two normonourished control groups, one infected and one uninfected by A. ceylanicum. Biochemical, haematological, parasitological and immunological parameters were evaluated. The results demonstrated that A. ceylanicum infection accentuated weight loss in obese animals compared to normonourished animals. However, obesity reduced the recovery of worms and oviposition of the females, and both infected groups showed decreased levels of haemoglobin, albumin, iron and erythrocytes. Significant relations were observed for pathogenesis in the following cases: infection interfered in lipid metabolism, which increased levels of total cholesterol and triglycerides in the obese group, and caused a decrease in HDL levels in both groups. Obesity led to an increase in glucose levels, and the infection exacerbated this parameter in both the normonourished and obese groups. Inflammation was intensified in obese animals that showed elevated macrophage and neutrophil activation in adipose tissue, enlargement of the spleen and accumulation of lipids in the liver and faeces. Despite the decrease in IFN-γ levels, the infection did not potentiated the expression of the Foxp3, IL-10 and IL-2 transcription factor for any of the infected groups, markers that could positively compensate the host from the damage caused by obesity.

Função neuromuscular do bíceps braquial em contração isométrica após termoterapia / Neuromuscular function of braquial biceps in isometric contraction after termotherapy

A alteração na temperatura de um tecido pode promover efeitos fisiológicos que levam a alterações circulatórias e nervosas, tais como vasodilatação e aumento na flexibilidade. Objetivo: Avaliar, através de uma avaliação neuromuscular não invasiva, como a termoterapia influencia na força muscular e nos sinais mioelétricos do bíceps braquial em contração isométrica. Métodos: Dezessete voluntários foram orientados a fazer contração isométrica do músculo bíceps braquial concomitantemente com a eletromiografia de superfície. A avaliação eletromiográfica e de força foram realizadas antes e após a intervenção com recursos termoterapêuticos: gelo (15 minutos) e ultrassom continuo (1MHz, 0.8W/cm2, 7 minutos). Resultados: Mostraram que as mulheres possuem menos força e ativam menos unidades motoras. No entanto, a frequência de disparos elétricos nas vias efetoras é maior, o que indica maior propensão à fadiga. Após a aplicação do calor, não foram observadas diferenças na resposta neuromuscular do bíceps braquial em contração. Já a crioterapia, promoveu redução significativa na força e no número de unidades motoras ativadas durante a contração. O resfriamento do tecido muscular promove a diminuição da ação das fibras musculares, uma vez que há redução da velocidade da condução do impulso nervoso e do reflexo do arco miotático. Além disso, a crioterapia também diminui a sensibilidade dos órgãos tendinosos de Golgi, aumenta a viscosidade sanguínea, provoca a vasoconstrição. Todos estes fatores, somam-se para culminar na diminuição da ativação neuromuscular e, consequentemente, na redução da força do músculo

The change in temperature of a biological tissue can promote physiological effects that lead to circulatory and nerve changes, such as vasodilation and increased flexibility. Objective: The objective of this study was to evaluate, through a noninvasive neuromuscular assessment, how thermotherapy influences the muscular strength and the myoelectric signals of the biceps brachial in isometric contraction. Methods: Seventeen volunteers were instructed to perform isometric contraction of the brachial biceps muscle concomitantly with surface electromyography. Electromyographic and force evaluation were performed before and after the intervention with thermotherapeutic resources that consisted of ice therapy for 15 minutes and continuous ultrasound (1MHz, 0.8W/cm2) for 7 minutes. Results: Women have less strength and fewer motor units. However, the frequency of electric inputs of the effector pathways is higher, which indicates a greater propensity to fatigue. After the application of heat, no differences were observed in the neuromuscular response of the contracting brachial biceps. The cryotherapy, however, promoted a significant reduction in the strength and number of motor units activated during the contraction. Conclusion: The cooling of muscle tissue promotes a decrease of muscle fibers activities, since there is a reduction in the velocity of nerve impulse conduction and the reflex of the myotatic arch. In addition, cryotherapy also decreases the sensitivity of the Golgi tendon organs, increases blood viscosity, and causes vasoconstriction. All these factors are combined to culminate in the decrease of neuromuscular activation and, consequently, in the reduction of muscle strength

Obesity induction in hamster that mimics the human clinical condition.

Although obesity is well established in hamsters, studies using diets with high levels of simple carbohydrate associated with lipids are necessary to assess the impact of this type of food in the body. In this study a high sugar and butter diet (HSB) and high temperature were employed towards this end. Obesity was successfully induced at a temperature of 30.3°C to 30.9°C after 38 days feeding the animals an HSB diet. It was shown that although diet is important for the induction of obesity, temperature is also essential because at a temperature slightly below the one required, obesity was not induced, even when the animals were fed for a longer period (150 days).The obese clinical condition was accompanied by biochemical and hematological changes, as increased cholesterol and triglyceride levels and increased leukocyte numbers, similar to alterations observed in obese humans. Furthermore, it was demonstrated that increasing the intake of simple carbohydrates associated with lipids provided evidence of inflammation in obese animals.

The crowding effect in Ancylostoma ceylanicum: density-dependent effects on an experimental model of infection.

This study compared the course of Ancylostoma ceylanicum infection in hamsters infected with different inocula and the consequences for the host and helminth populations. The average of adult worms recovered, according to the number of third stage larva used, were 28.0, 24.8, 24.6, and 24.8% to inocula size of 25 L3, 75 L3, 125 L3, and 250 L3, respectively. The size of the inoculum did not affect the establishment, survival, or fecundity of adult helminths. Reductions in the red blood cell and hemoglobin levels in the infected group were inversely proportional to the number of white blood cells. Moreover, differential cell counting revealed a positive correlation between the worm load and leucocyte numbers. The humoral response against excretion-secretion antigens was more robust and sensitive compared with the response against crude extract, with no direct linear correlation with the number of worms. The effect of the population density was more evident in females.

Identification of a new Schistosoma mansoni SMYB1 partner: putative roles in RNA metabolism.

SMYB1 is a Schistosoma mansoni protein highly similar to members of the Y-box binding protein family. Similar to other homologues, SMYB1 is able to bind double- and single-stranded DNA, as well as RNA molecules. The characterization of proteins involved in the regulation of gene expression in S. mansoni is of great importance for the understanding of molecular events that control morphological and physiological changes in this parasite. Here we demonstrate that SMYB1 is located in the cytoplasm of cells from different life-cycle stages of S. mansoni, suggesting that this protein is probably acting in mRNA metabolism in the cytoplasm and corroborating previous findings from our group that showed its ability to bind RNA. Protein-protein interactions are important events in all biological processes, since most proteins execute their functions through large supramolecular structures. Yeast two-hybrid screenings using SMYB1 as bait identified a partner in S. mansoni similar to the SmD3 protein of Drosophila melanogaster (SmRNP), which is important in the assembly of small nuclear ribonucleoprotein complexes. Also, pull-down assays were conducted using immobilized GST-SMYB1 proteins and confirmed the SMYB1-SmRNP interaction. The interaction of SMYB1 with a protein involved in mRNA processing suggests that it may act in processes such as turnover, transport and stabilization of RNA molecules.

Evaluation of parasitological and immunological aspects of acute infection by Ancylostoma caninum and Ancylostoma braziliense in mixed-breed dogs.

This study compared the course of infection by Ancylostoma caninum and Ancylostoma braziliense in mixed-breed dogs infected with L3 larvae. Dogs infected with A. caninum eliminated more eggs than did those infected with A. braziliense. A total of 38 % of A. caninum and 44 % of A. braziliense larvae were recovered as adult worms. There were no marked clinical abnormalities in dogs with either infection. A. caninum was associated with anemia and an increased number of circulating neutrophils, whereas infection with A. braziliense led to a decrease in the number of leukocytes. The humoral response against excreted and secreted antigens from adult worms was more sensitive and specific than the response induced with the crude antigen. No immune response was observed for either crude or excreted-secreted (ES) antigens from larvae of either species. A nonspecific response against the crude antigen of A. braziliense was found at 0 and 7 days postinfection and maintained throughout the infection period. However, antibody titers against ES antigens were elevated in A. caninum infection at patency and death, showing that this antigen has a higher specificity. The immune response elicited by infection with A. braziliense in dogs has not been described previously. No significant differences were observed in the infection processes of the two Ancylostoma species, except for the higher number of eggs eliminated from dogs infected with A. caninum, which may indicate a better evolutionary adaptation of the parasite to its host in comparison with A. braziliense.

Prednisolone and cyclosporine A: effects on an experimental model of ancylostomiasis.

Corticosteroids and cyclosporine A (CsA) are important clinical immunosuppressive drugs used in the maintenance of organ transplants and in suppressing undesired autoimmune or allergic immune responses. To study the effect of CsA and prednisolone on the course of an Ancylostoma ceylanicum infection, hamsters were treated with commercially available prednisolone or CsA. For both drugs, half the recommended dose was sufficient to inhibit the proliferation of more than 70% of hamster lymph node cells. There was no difference in the recovery of adult worms; however, animals treated with prednisolone presented with low egg counts in the feces. Infection with A. ceylanicum resulted in an increase in specific antibodies against adult worm antigens, but hamsters treated with either drug presented with lower IgG titers. We observed that A. ceylanicum infection caused peripheral cellular immune suppression, which is characterized by a reduction in the total white cell count, neutropenia and lymphopenia. We also observed a lymphoplasmacytic pattern and few eosinophils in the mucosal inflammatory infiltrate for all the animals. The animals treated with prednisolone showed changes in the architecture of the intestine, including the loss of the mucosa, intense congestion and inflammation. In spleen, we observed hyperplasia of white pulp in all infected animals; in addition, there was a loss of tissue architecture in the animals treated with prednisolone. In conclusion, this work shows that an A. ceylanicum infection leads to acute peripheral cellular immune suppression in hamsters but not humoral immune suppression and that CsA treatment does not interfere with the process of infection. However, prednisolone treatment causes intestinal injury, what could hamper the parasite attachment to the intestinal wall, and as a result affects copulation and, consequently, decreases the number of eggs eliminated in the feces. Moreover, the possibility that the drug can also be exerting an effect on female fertility should be considered.

Effect of temperature on activity of third-stage larvae of Angiostrongylus vasorum.

To evaluate the effect of temperature on the activity and mortality of the L3 of Angiostrongylus vasorum, 1,500 L3 were isolated from experimentally infected snails and distributed into five equal groups. Three groups were incubated at 37°C, 27°C, and 5°C. The remaining two groups were incubated at 27°C and 5°C for 10 days, at which time the temperature for the 27°C group was reduced to 5°C and the 5°C group increased to 27°C. Larva activity was observed daily and inactive larvae were removed. At 37°C, larvae survived up to 8 days. At 27°C, larvae were active until day 6. When subjected to a reduction in temperature from 27°C to 5°C beginning on day 10, the number of active larvae increased until day 13. Only on day 17 did the number of active larvae decline to zero. At 5°C, larvae remained active until day 15, surviving to 24 days. When temperature was increased from 5°C to 27°C beginning on day 10, larvae were found active until day 12 and maintained an intermediate level of activity to day 21. Survival of larvae was greater at lower temperatures, while high temperatures were associated with higher mortality.

Evidence for reductive genome evolution and lateral acquisition of virulence functions in two Corynebacterium pseudotuberculosis strains.

BACKGROUND: Corynebacterium pseudotuberculosis, a gram-positive, facultative intracellular pathogen, is the etiologic agent of the disease known as caseous lymphadenitis (CL). CL mainly affects small ruminants, such as goats and sheep; it also causes infections in humans, though rarely. This species is distributed worldwide, but it has the most serious economic impact in Oceania, Africa and South America. Although C. pseudotuberculosis causes major health and productivity problems for livestock, little is known about the molecular basis of its pathogenicity. METHODOLOGY AND FINDINGS: We characterized two C. pseudotuberculosis genomes (Cp1002, isolated from goats; and CpC231, isolated from sheep). Analysis of the predicted genomes showed high similarity in genomic architecture, gene content and genetic order. When C. pseudotuberculosis was compared with other Corynebacterium species, it became evident that this pathogenic species has lost numerous genes, resulting in one of the smallest genomes in the genus. Other differences that could be part of the adaptation to pathogenicity include a lower GC content, of about 52%, and a reduced gene repertoire. The C. pseudotuberculosis genome also includes seven putative pathogenicity islands, which contain several classical virulence factors, including genes for fimbrial subunits, adhesion factors, iron uptake and secreted toxins. Additionally, all of the virulence factors in the islands have characteristics that indicate horizontal transfer. CONCLUSIONS: These particular genome characteristics of C. pseudotuberculosis, as well as its acquired virulence factors in pathogenicity islands, provide evidence of its lifestyle and of the pathogenicity pathways used by this pathogen in the infection process. All genomes cited in this study are available in the NCBI Genbank database (http://www.ncbi.nlm.nih.gov/genbank/) under accession numbers CP001809 and CP001829.

Angiostrongylus vasorum (Baillet, 1866) Kamensky, 1905: emergence of third-stage larvae from infected Biomphalaria glabrata snails.

Biomphalaria glabrata snails were experimentally infected with Angiostrongylus vasorum first-stage larvae and divided into four groups of 30 snails. To assess the shedding of third-stage larvae (L3), the snails were maintained under different stimuli: group 1 60 W light bulb for 24 h, group 2 37 degrees C water bath for 24 h, group 3 room temperature (23-25 degrees C) for 24 h, Group 4 room temperature (23-25 degrees C) for up to 15 days. After 24 h, a total of 512 A. vasorum L3, alive and active, were released by snails from group 1, while 2,446 L3 were released from group 2 and five L3 from group 3. After 15 days, snails from group 4 released a total of 44 L3. To evaluate the infectivity of A. vasorum L3, two mongrel dogs were successfully infected with L3 released by snails from groups 1 and 2, confirming that the infection of dogs with A. vasorum L3 was possible, independently of ingestion of the mollusk intermediate host. The results shown in these experiments suggest that angiostrongylosis could be directly transmitted to the definitive hosts, with implications for the parasite's life cycle.