Helminth infection modulates number and function of adipose tissue Tregs in high fat diet-induced obesity.

BACKGROUND: Epidemiological and experimental studies have shown a protective effect of helminth infections in weight gain and against the development of metabolic dysfunctions in the host. However, the mechanisms Treg cells exert in the helminth-obesity interface has been poorly investigated. The present study aimed to verify the influence of Heligmosomoides polygyrus infection in early stages of high fat diet-induced obesity. PRINCIPAL FINDINGS: The presence of infection was able to prevent exacerbated weight gain in mice fed with high fat diet when compared to non-infected controls. In addition, infected animals displayed improved insulin sensitivity and decreased fat accumulation in the liver. Obesity-associated inflammation was reduced in the presence of infection, demonstrated by lower levels of leptin and resistin, lower infiltration of Th1 and Th17 cells in adipose tissue, higher expression of IL10 and adiponectin, increased infiltration of Th2 and eosinophils in adipose tissue of infected animals. Of note, the parasite infection was associated with increased Treg frequency in adipose tissue which showed higher expression of cell surface markers of function and activation, like LAP and CD134. The infection could also increase adipose Treg suppressor function in animals on high fat diet. CONCLUSION: These data suggest that H. polygyrus modulates adipose tissue Treg cells with implication for weight gain and metabolic syndrome.

Morita-Baylis-Hillman adducts derived from thymol: synthesis, in silico studies and biological activity against Giardia lamblia.

Giardiasis is a neglected disease, and there is a need for new molecules with less side effects and better activity against resistant strains. This work describes the evaluation of the giardicidal activity of thymol derivatives produced from the Morita-Baylis-Hillman reaction. Thymol acrylate was reacted with different aromatic aldehydes, using 1,4-diazabicyclo[2.2.2]octane (DABCO) as a catalyst. Eleven adducts (8 of them unpublished) with yields between 58 and 80% were obtained from this reaction, which were adequately characterized. The in silico prediction showed theoretical bioavailability after oral administration as well as antiparasitic activity against Giardia lamblia. Compound 4 showed better biological activity against G. lamblia. In addition to presenting antigiardial activity 24 times better than thymol, this MBHA was obtained in a short reaction time (3 h) with a yield (80%) superior to the other investigated molecules. The molecule was more active than the precursors (thymol and MBHA 12) and did not show cytotoxicity against HEK-293 or HT-29 cells. In conclusion, this study presents a new class of drugs with better antigiardial activity in relation to thymol, acting as a basis for the synthesis of new bioactive molecules. Molecular hybridization technique combined with the Morita-Baylis-Hillman reaction provided new thymol derivatives with giardicidal activity superior to the precursor molecules.

Effect of dexamethasone on experimental enteritis produced by Giardia lamblia in a Meriones unguiculatus model.

Our aim was to evaluate the impact of immunosuppression on the development of giardiasis. Thirty-six gerbils (4-6 weeks old) were distributed in four groups containing nine animals each: Control (CT); Control-Infected by Giardia lamblia (CTIn), Immunosuppressed (IS), and Immunosuppressed-Infected by G. lamblia (ISIn). Animals in the IS and ISIn groups received intramuscular dexamethasone solution for 25 days. On the 11th day, the animals in the CTIn and ISIn groups were inoculated with G. lamblia. After 14 days of infection, the 25th day of the experiment, all groups were euthanized. Four hours after euthanasia, the intestinal permeability was evaluated and sections of the duodenum and spleen were harvested for morphometric and histopathological analyses. Immunosuppressed groups showed a significant increase in intestinal permeability compared to control and infected groups. Considering that the infection can become chronic in immunosuppressed groups, we should be alert to the possibilities of chronic inflammatory changes, both locally and systemically, due to the loss of the intestinal barrier. Lesions were observed in the duodenal mucosa of the gerbils of the CTIn group, with reduced villi size, crypt hyperplasia, edema, and the presence of inflammatory infiltrate in the lamina propria. In the ISIn group, we observed no inflammation, long and intact villi, and a significant increase in the area of intestinal mucins, despite the large number of trophozoites identified. Our results suggest that exacerbation of the immune response has a direct relationship with the appearance of lesions during enteritis produced by G. lamblia in the assessed model.

Obesity-induced diet leads to weight gain, systemic metabolic alterations, adipose tissue inflammation, hepatic steatosis, and oxidative stress in gerbils (Meriones unguiculatus).

BACKGROUND: Nowadays, the number of obese people in the world has reached alarming proportions. During the expansion of adipose tissue, a number of functions such as activation and release of cytokines and hormones may be affected. This leads the body to a pro-inflammatory pattern, which may affect the proper functioning of many tissues. Thus, studying the mechanisms by which obesity induces physiological disorders is necessary, and may be facilitated by the use of animal models, in particular rodents. We sought to characterize the metabolic and adipose tissue changes resulting from a diet rich in fats and simple sugars in gerbils. METHODS: We divided 14 gerbils into two experimental groups that received a diet rich in simple carbohydrates and fats with 5,86 kcal/g (OB, n = 7) or a standard diet with 4.15 kcal/g (CT; n = 7) for 11 weeks. The animals had free access to water and food. The animal weight and food consumption were measured weekly. Blood, adipose tissue and liver of each animal were collected at the end of experiment. The following parameters were determined: cholesterol (COL), triglycerides (TGL) and glycemia (GLI) in the plasma; cytokines (IL-6, IL-10 and TNF-α) and hormones (adiponectin and leptin) in adipose tissue; activity of superoxide dismutase (SOD) and catalase (CAT), extraction and differentiation of fat and histology in liver. RESULTS: The consumption of a diet rich in simple carbohydrates and fats led to increased total body weight and increased relative weights of liver and adipose tissue. In addition, we observed increased fasting glucose levels and circulating triglycerides, along with high TNF-α production in adipose tissue and increased total fat, cholesterol and triglyceride contents in the liver, contributing to higher intensity of hepatic steatosis. On the other hand, the animals of this group showed depletion in the enzyme activity of SOD and CAT in the liver, as well as reduction of IL-10 and adiponectin levels in adipose tissue. DISCUSSION: High intake of saturated fat and simple carbohydrates establish the gerbil as an experimental model for the study of metabolic and hepatic abnormalities resulting from obesity.

Genetic differences between two Leishmania major-like strains revealed by suppression subtractive hybridization.

Leishmania major, the causative agent of zoonotic leishmaniasis, is restricted to Old World countries. Molecular and biochemical techniques have been used to identify some L. major-like isolated in South America including Brazil. Here, two L. major-like strains, one virulent (BH49) and one non-virulent (BH121), were subjected to suppression subtractive hybridization (SSH) technique in order to identify differentially expressed genes. SSH technique identified nine cDNA fragments exhibiting high homology to previously sequenced L. major genes. Five cDNAs (four specific for BH49 and one for BH121) were confirmed by RT-PCR. Among those differentially expressed subtracted genes, some were involved in physiological processes including metabolism, translation and destination of proteins, production of energy, virulence factors and unknown functions. Western-blot analysis confirmed a higher expression level of ß-1,3-galactosyl residues in L. major-like lipophosphoglycan (LPG). This molecular analysis opens the possibility for identification of potential virulence factors not only in different strains, but also in others species of Leishmania.

Differentially expressed genes of virulent and nonvirulent Entamoeba histolytica strains identified by suppression subtractive hybridization.

Entamoeba histolytica is a parasite which presents capacity to degrade tissues and therefore has a pathogenic behavior. As this behavior is not shown by all strains, there have been several studies investigating molecular basis of the cytotoxicity process. Using the suppression subtractive hybridization (SSH) technique, differential gene expressions of two E. histolytica strains, one virulent (EGG) and one nonvirulent (452), have been analyzed with the purpose of isolating genes which may be involved with amoebic virulence. Nine cDNA fragments presenting high homology with E. histolytica previously sequenced genes were subtracted. Of these, four genes were confirmed by RT-PCR. Two coding for hypothetical proteins, one for a cysteine-rich protein, expressed only in the virulent strain, EGG and another one, coding for grainin 2 protein, exclusive from 452 strain. This study provided new insight into the proteins differences in the virulent and nonvirulent E. histolytica strains. We believe that further studies with these proteins may prove association of them with tissue damage, providing new perceptions to improve treatment or diagnosis of the invasive disease.

Retinopathy of prematurity screening and treatment cost in Brazil.

OBJECTIVE: To assess the additional cost of incorporating the detection and treatment of retinopathy of prematurity (ROP) into neonatal care services of Brazil's Unified Health System (SUS). METHODS: A deterministic decision-tree simulation model was built to estimate the direct costs of screening for and treating ROP in neonatal intensive-care units (NICUs), based on data for 869 preterm infants with birth weight less than 1 500 g examined in six governmental NICUs in the capital city of Rio de Janeiro, where coverage was 52% and 8% of infants were treated. All of the parameters from this study were extrapolated to Brazilian newborn estimates in 2010. Costs of screening and treatment were estimated considering staff, equipment and maintenance, and training based on published data and expert opinion. A budget impact analysis was performed considering the population of preterm newborns, screening coverage, and the incidence of treatable ROP. One- and two-way sensitivity analyses were performed. RESULTS: In Rio de Janeiro, unit costs per newborn were US$ 18 for each examination, US$ 398 per treatment, and US$ 29 for training. The estimated cost of ROP diagnosis and treatment for all at-risk infants NICUs was US$ 80 per infant. The additional cost to the SUS for one year would be US$ 556 640 for a ROP program with 52% coverage, increasing to US$ 856 320 for 80% coverage, and US$ 1.07 million or 100% coverage. CONCLUSIONS: The results of this study indicate that providing ROP care is affordable within the framework of the SUS in Brazil, and might be feasible elsewhere in Latin America, considering the evidence of the effectiveness of ROP treatment and the social benefits achieved.

Retinopathy of prematurity screening and treatment cost in Brazil / Costo de la detección y el tratamiento de la retinopatía de la prematuridad en el Brasil

OBJECTIVE: To assess the additional cost of incorporating the detection and treatment of retinopathy of prematurity (ROP) into neonatal care services of Brazil's Unified Health System (SUS). METHODS: A deterministic decision-tree simulation model was built to estimate the direct costs of screening for and treating ROP in neonatal intensive-care units (NICUs), based on data for 869 preterm infants with birth weight less than 1 500 g examined in six governmental NICUs in the capital city of Rio de Janeiro, where coverage was 52% and 8% of infants were treated. All of the parameters from this study were extrapolated to Brazilian newborn estimates in 2010. Costs of screening and treatment were estimated considering staff, equipment and maintenance, and training based on published data and expert opinion. A budget impact analysis was performed considering the population of preterm newborns, screening coverage, and the incidence of treatable ROP. One- and two-way sensitivity analyses were performed. RESULTS: In Rio de Janeiro, unit costs per newborn were US$ 18 for each examination, US$ 398 per treatment, and US$ 29 for training. The estimated cost of ROP diagnosis and treatment for all at-risk infants NICUs was US$ 80 per infant. The additional cost to the SUS for one year would be US$ 556 640 for a ROP program with 52% coverage, increasing to US$ 856 320 for 80% coverage, and US$ 1.07 million or 100% coverage. CONCLUSIONS: The results of this study indicate that providing ROP care is affordable within the framework of the SUS in Brazil, and might be feasible elsewhere in Latin America, considering the evidence of the effectiveness of ROP treatment and the social benefits achieved.

OBJETIVO: Evaluar el costo adicional de incorporar la detección y el tratamiento de la retinopatía de la prematuridad (RP) en los servicios de atención neonatal del Sistema Único de Salud (SUS) del Brasil. MÉTODOS: Se estableció un modelo de simulación determinístico en forma de árbol de decisión para calcular los costos directos del tamizaje y el tratamiento de la RP en las unidades de cuidados intensivos neonatales (UCIN), con base en los datos correspondientes a 869 lactantes prematuros con un peso al nacer inferior a 1 500 g examinados en seis UCIN gubernamentales de Rio de Janeiro, capital del estado del mismo nombre, donde la cobertura fue de 52% y se trató a un 7% de los lactantes. Todos los parámetros de este estudio se extrapolaron a los cálculos de recién nacidos brasileños correspondientes al año 2010. Se calcularon los costos de la detección y el tratamiento, teniendo en cuenta el personal, el equipo y la capacitación, con base en los datos publicados y la opinión de los expertos. Se llevó a cabo un análisis de la repercusión presupuestaria considerando la población de recién nacidos prematuros, la cobertura del tamizaje y la incidencia de RP susceptible de tratamiento. Se realizaron análisis de sensibilidad en uno y dos sentidos. RESULTADOS: En Rio de Janeiro, los costos unitarios por recién nacido fueron de US$ 18 por cada examen, US$ 398 por tratamiento y US$ 29 por capacitación. El costo calculado del diagnóstico y el tratamiento de la RP en todos los lactantes en situación de riesgo de las UCIN fue de US$ 80 por lactante. El costo anual adicional para el SUS de un programa de RP con una cobertura de 52% sería de US$ 556 640, y ascendería a US$ 856 320 para una cobertura de 80%, y a US$ 1,07 millones si la cobertura fuera de 100%. CONCLUSIONES: Los resultados de este estudio indican que, teniendo en cuenta los datos probatorios de la eficacia del tratamiento de la RP y los beneficios sociales obtenidos, la prestación de asistencia a la RP es asequible en Brasil en el marco del SUS y podría ser factible en otros lugares de América Latina.

Entamoeba histolytica: gene expression analysis of cells invading tissues.

Entamoeba histolytica is a protozoan parasite that presents a risk to the health of millions of people worldwide. Due to the existence of different clinical forms caused by the parasite and also different virulence levels presented by one strain, one would expect differences in the profile of gene transcripts between virulent and nonvirulent cultures. In this study we used the differential display to select gene segments related to invasiveness of amoeba. One Brazilian strain of E. histolytica in two conditions, able or not to cause lesions in experimental animals, was used. RNA from this strain, was used to study the differential expression of genes. 29 specific gene fragments differentially expressed in the virulent strain were selected. By real-time PCR, six of these genes had confirmed their differential expression in the virulent culture. These genes may have important roles in triggering invasive amoebiasis and may be related to adaptation of trophozoites to difficulties encountered during colonization of the intestinal epithelium and liver tissue. Future studies with these genes may elucidate its actual role in tissue invasion by E. histolytica generating new pathways for diagnosis and treatment of amoebiasis.

High prevalence of enteroparasitosis in urban slums of Belo Horizonte-Brazil. Presence of enteroparasites as a risk factor in the family group.

The present study evaluates the prevalence of enteroparasitosis in the urban slums of Belo Horizonte, Brazil and the risk of transmitting enteroparasites to the family members of infected individuals. Stool samples were collected and examined at clinical laboratories near each slum. Individuals were identified and classified as positive for parasitosis (IP(+)), and individuals with negative stool tests were classified as negative for parasitosis (IP(-)) and enrolled as control patients. We collected samples from 594 patients, of which 20·2% and 79·8% were classified as IP(+) and IP(-), respectively. In addition, 744 family members (FIPs) effectively participated in the study by providing fecal samples. In total, 1338 participants were evaluated. Of these, 34·6% were tested positive for parasitosis. Blastocystis was the most prevalent parasite, infecting 22·4% of individuals. Among FIPs, the overall prevalence was 46·1%. Of these, 50·6% and 44·7% were classified as FIPs(+) and FIPs(-), respectively. These results showed that IP(+) did not impact the prevalence of infection within the studied communities, not constituting index cases of specific risk behaviors, suggesting that, in fact, these communities are exposed to similar oral-fecal routes of contamination.

Prevalence of intestinal parasitism and associated symptomatology among hemodialysis patients.

Intestinal parasites are an important cause of morbidity and mortality. Immunocompromised individuals may develop more severe forms of these infections. Taking into account the immunity impairment in patients suffering from chronic renal failure (CRF), we will determine the prevalence and associated symptoms of intestinal parasites in these patients. Controls without CRF were used for comparison. Stool samples were collected and processed for microscopic identification of parasites using the Formalin-ether concentration method. For Cryptosporidium diagnosis, the ELISA technique was used. One hundred and ten fecal samples from hemodialysis patients were analyzed, as well as 86 from a community group used as control group. A result of 51.6% of intestinal parasites was observed in hemodialysis patients and 61.6% in the control group. Cryptosporidium and Blastocystis were the most common infections in patients with CRF (26.4% and 24.5%, respectively). Blastocystis was the most common infection in the control group (41.9%), however no individual was found positive for Cryptosporidium. Among the CRF patients, 73.6% were symptomatic, 54.3% of these tested positive for at least one parasite, in contrast to 44.8% in asymptomatic patients (p = 0.38). The most common symptoms in this group were flatulence (36.4%), asthenia (30.0%) and weight loss (30.0%). In the control group, 91.9% were symptomatic, 60.8% of these tested positive for at least one parasite, in contrast to 71.4% in asymptomatic patients (p = 0.703). A significant difference between the two groups was observed with regard to symptoms, with bloating, postprandial fullness, and abdominal pain being more frequent in the control group than in the hemodialysis group (all p < 0.05). Comparing symptomatic with asymptomatic, there was no association in either group between symptoms or the prevalence of parasitic infection, nor with the type of parasite or with multiple parasitic infections. Patients with chronic renal failure are frequent targets for renal transplantation, which as well as the inherent immunological impairment of the disease itself, results in immunosuppression by medication. For this reason, carriers of intestinal parasites with pathogenic potential can develop serious clinical complications influencing the success of transplantation. This fact, coupled with the high prevalence of intestinal parasites and the dissociation between symptoms and infection in CRF patients, suggests that the stool test should be incorporated in routine propedeutics. Furthermore, preventive measures for the acquisition of parasites through the fecal-oral contamination route should be introduced.

Prevalence of ittestinal parasitism and associated symptomatology among hemodialysis patients / Prevalência de parasitismo intestinal e sintomatologia associada em pacientes hemodialíticos

Intestinal parasites are an important cause of morbidity and mortality. Immunocompromised individuals may develop more severe forms of these infections. Taking into account the immunity impairment in patients suffering from chronic renal failure (CRF), we will determine the prevalence and associated symptoms of intestinal parasites in these patients. Controls without CRF were used for comparison. Stool samples were collected and processed for microscopic identification of parasites using the Formalin-ether concentration method. For Cryptosporidium diagnosis, the ELISA technique was used. One hundred and ten fecal samples from hemodialysis patients were analyzed, as well as 86 from a community group used as control group. A result of 51.6% of intestinal parasites was observed in hemodialysis patients and 61.6% in the control group. Cryptosporidium and Blastocystis were the most common infections in patients with CRF (26.4% and 24.5%, respectively). Blastocystis was the most common infection in the control group (41.9%), however no individual was found positive for Cryptosporidium. Among the CRF patients, 73.6% were symptomatic, 54.3% of these tested positive for at least one parasite, in contrast to 44.8% in asymptomatic patients (p = 0.38). The most common symptoms in this group were flatulence (36.4%), asthenia (30.0%) and weight loss (30.0%). In the control group, 91.9% were symptomatic, 60.8% of these tested positive for at least one parasite, in contrast to 71.4% in asymptomatic patients (p = 0.703). A significant difference between the two groups was observed with regard to symptoms, with bloating, postprandial fullness, and abdominal pain being more frequent in the control group than in the hemodialysis group (all p < 0.05). Comparing symptomatic with asymptomatic, there was no association in either group between symptoms or the prevalence of parasitic infection, nor with the type of parasite or with multiple parasitic infections. Patients with chronic renal failure are frequent targets for renal transplantation, which as well as the inherent immunological impairment of the disease itself, results in immunosuppression by medication. For this reason, carriers of intestinal parasites with pathogenic potential can develop serious clinical complications influencing the success of transplantation. This fact, coupled with the high prevalence of intestinal parasites and the dissociation between symptoms and infection in CRF patients, suggests that the stool test should be incorporated in routine propedeutics. Furthermore, preventive measures for the acquisition of parasites through the fecal-oral contamination route should be introduced.

Doenças parasitárias infectam grande número de indivíduos em todo o mundo. Manifestações clínicas mais severas podem se apresentar em pacientes imunocomprometidos. Considerando o importante comprometimento imunológico observado em pacientes com insuficiência renal crônica (IRC), foi determinada a prevalência e sintomas associados a parasitoses intestinais nesses pacientes em comparação a controles saudáveis. Foram coletadas amostras fecais de cada participante e processadas para identificação microscópica dos parasitas pelo método de concentração por formol-éter. Foi utilizada a técnica de ELISA para identificar coproantígenos de Cryptosporidium. Foram analisadas 110 amostras fecais de pacientes em hemodiálise e 86 de um grupo controle comunitário. Cryptosporidium e Blastocystis foram as infecções mais freqüentes nos pacientes em hemodiálise (26,4% e 24,5%, respectivamente). Blastocystis foi a infecção mais freqüente no grupo controle (41,9%), entretanto nenhum indivíduo positivo para Cryptosporidium foi identificado. Considerando os pacientes com IRC, 73,6% eram sintomáticos, sendo 54,3% positivos para algum parasita, contra 44,8% nos assintomáticos (p = 0,38). Os sintomas mais frequentes neste grupo foram flatulência (36,4%), adinamia (30,0%) e perda de peso (30,0%). No grupo controle, 91,9% eram sintomáticos, sendo 60,8% positivos para algum parasita, contra 71,4% nos assintomáticos (p = 0,703). Em relação aos sintomas, houve diferença significativa entre os dois grupos, sendo que flatulência, plenitude pós-prandial, e dor abdominal foram mais freqüentes no grupo controle que nos pacientes em hemodiálise (todos p < 0,05). Comparando-se sintomáticos com assintomáticos, não houve associação entre a sintomatologia e a prevalência de parasitose, nem com o tipo de parasita, e nem com o poliparasitismo, nos dois grupos. Considerando que pacientes com IRC são frequentes alvos de transplante renal, resultando em imunossupressão por medicamentos, que é somada à deficiência imunológica inerente à própria doença. Os portadores de parasitas intestinais com potencial patogênico podem desenvolver sérias complicações clínicas que influenciam o sucesso do transplante. Este fato, aliado a alta prevalência de parasitas intestinais e dissociação entre os sintomas e infecção nesses pacientes, sugerem a incorporação do exame de fezes na propedêutica de rotina dos mesmos, juntamente com medidas preventivas para a aquisição de parasitas com rota de contaminação fecal-oral.

Impact of protein malnutrition on histological parameters of experimentally infected animals with Giardia lamblia.

Giardiasis is one of the most common parasitic diseases worldwide, and the disease is an important cause of diarrhoea and malabsorption in children and immunosuppressed individuals. However, there is no evidence that characterises malnutrition as an aggravating factor for this disease. We evaluated changes in villi structures to examine the association between malnutrition and Giardia lamblia infection. We used 32 gerbils, divided into 4 groups: Control (CT) and Control Infected (CTIn), which each received a 20% protein diet, Malnourished (MN) and Malnourished Infected (MNIn), which each received a 5% protein diet. Groups CTIn and MNIn were inoculated with 1×10(6) trophozoites of G. lamblia, while the remaining groups were mock infected. Seven days post-infection, all groups were sacrificed, and the proximal portions of the small intestines were collected for the analysis of villus height, mucus area and extent of Giardia infection. Gerbils fed with a low-protein diet had significantly lower body weights. Malnourished infected animals presented significantly increased production of mucus, suggesting a synergism occurs between malnutrition and Giardiasis, potentially to control the adhesion of Giardia in the mucosa. Villus height was significantly lower in group MNIn compared to CTIn. This work suggests that malnutrition contributes to severity of Giardiasis by decreasing the intestinal absorption capacity via shortening of the villi.

Effects of metronidazole analogues on Giardia lamblia: experimental infection and cell organization.

The chemotherapeutic agents used for the treatment of giardiasis are often associated with adverse side effects and are refractory cases, due to the development of resistant parasites. Therefore the search for new drugs is required. We have previously reported the giardicidal effects of metronidazole (MTZ) and its analogues (MTZ-Ms, MTZ-Br, MTZ-N(3), and MTZ-I) on the trophozoites of Giardia lamblia. Now we evaluated the activity of some giardicidal MTZ analogues in experimental infections in gerbils and its effects on the morphology and ultrastructural organization of Giardia. The giardicidal activity in experimental infections showed ED(50) values significantly lower for MTZ-I and MTZ-Br when compared to MTZ. Transmission electron microscopy was employed to approach the mechanism(s) of action of MTZ analogues upon the protozoan. MTZ analogues were more active than MTZ in changing significantly the morphology and ultrastructure of the parasite. The analogues affected parasite cell vesicle trafficking, autophagy, and triggered differentiation into cysts. These results coupled with the excellent giardicidal activity and lower toxicity demonstrate that these nitroimidazole derivates may be important therapeutic alternatives for combating giardiasis. In addition, our results suggest a therapeutic advantage in obtaining synthetic metronidazole analogues for screening of activities against other infectious agents.

Difficulties in the dissemination and implementation of clinical guidelines in government neonatal intensive care units in Brazil: how managers, medical and nursing, position themselves.

RATIONALE, AIMS AND OBJECTIVES: Clinical guidelines are tools that systematize scientific evidence and help to achieve proper care. Several difficulties are reported regarding the effective use, such as the shortcomings in the level of knowledge and attitudes by the professionals, the service structure and the preferences appointed by patients. An analysis of these difficulties was the objective of this study in the context of government Neonatal Intensive Care Units (NICU) in Brazil. METHOD: A semi-structured survey was carried out with 53 managers (medical and nursing) of the 15 NICU in a convenient sample of two groups of government units in Brazil. The managers chose their answers from a list of difficulties to implement the guidelines based on the analytical model of Cabana and graded the difficulties found on a 5-point scale with no reference to quality. RESULTS: Respondents have reported several difficulties with the following priority: lack of professionals to provide care, being perceived as more critical within the nursing and physiotherapy crews, minor participation of professionals in the discussion process and inadequate infrastructure. The lack of acquaintance with the guidelines by the professionals has been reported by few of the surveyed. CONCLUSION: These findings show some common ground to literature pointing the importance of adequate infrastructure. Managers showed a low valuation of both the level of knowledge and the professionals' adhesion to the guidelines.

Melatonin reduces the severity of experimental amoebiasis.

BACKGROUND: Melatonin has immunomodulatory effects but very little is known about its influence in protozoan infections, such as Entamoeba histolytica, which causes amoebiasis, a disease with significant morbidity and mortality. In this study, we evaluated the effects of exogenous melatonin interference in experimental amoebiasis and on interactions between human blood cells and E. histolytica trophozoites. METHODS: The effect of melatonin was investigated in models of experimental amoebiasis in hamsters and rats by evaluating the area of necrosis induced by E. histolytica. The activity of melatonin on the interactions between leukocytes and amoebae was determined by examining leukophagocytosis. For in vitro tests, polymorphonuclear and mononuclear human blood leucocytes were incubated with E. histolytica trophozoites. RESULTS: The areas of amoebic necrosis were significantly reduced in animals treated with melatonin. Melatonin treatment increased leukophagocytosis but was associated with a greater number of dead amoebae. CONCLUSIONS: These results suggest that melatonin may play a beneficial role in the control of amoebic lesions, raising the possibility that this drug may be used as an adjuvant in anti-amoebic therapy.

Entamoeba histolytica and E. dispar trophozoites in the liver of hamsters: in vivo binding of antibodies and complement.

BACKGROUND: Human amoebiasis is caused by the parasitic protozoan Entamoeba histolytica that lives in the large intestine of hosts, where can produce asymptomatic colonization until severe invasive infections with blood diarrhea and spreading to other organs. The amoebic abscesses in liver are the most frequent form of amoebiasis outside intestine and still there are doubts about the pathogenic mechanisms involved in their formation. In this study we evaluated the in situ binding of antibodies, C3 and C9 complement components on trophozoites, in livers of hamsters infected with E. histolytica or E. dispar. These parameters were correlated with the extension of the hepatic lesions observed in these animals and with trophozoites survivor. METHODS: Hamsters were inoculated intra-hepatically with 100,000 trophozoites of E. histolytica or E. dispar strain and necropsied 12, 24, 48, 72, 144 and 192 h after inoculation. Antibodies, C3 and C9 binding to trophozoites were detected by immunohistochemistry. The estimation of the necrosis area and the number of labeled trophozoites was performed using digital morphometry analysis. RESULTS: In the liver sections of animals inoculated with the amoebas, the binding of antibodies to E. histolytica trophozoites was significantly lower than to E. dispar trophozoites. Trophozoites of E. dispar were also more frequently vacuolated and high labeled cellular debris observed in the lesions. Positive diffuse reaction to C3 complement component was more intense in livers of animals inoculated with E. histolytica after 24 and 72 h of infection. C3(+) and C9(+) trophozoites were detected in the vascular lumen, granulomas and inside and in the border of necrotic areas of both infected group animals. C3(+) and C9(+) trophozoite debris immunostaining was higher in livers of E. dispar than in livers of E. histolytica. A positive correlation between necrotic areas and number of C9(+) trophozoites was observed in animals inoculated with E. dispar. CONCLUSION: Morphological and immunohistochemical results suggest that antibodies and complement are able to bind and destroy some trophozoites in the liver of experimentally infected hamsters, perhaps selecting the more resistant parasites which are responsible by progression of amoebic abscesses. The findings indicate that E. histolytica possesses an enhanced ability in vivo to evade the immune responses compared to E. dispar, although it also causes experimental hepatic lesions.