Structural changes in the jejunal mucosa of mice infected with Schistosoma mansoni, fed low or high protein diets

The effects of high and low-protein diets on the structure of the jejunal mucosa were studied in Schistosoma mansoni infected mice (morphology and histomorphometry). Weaning male albino mice were infected with 80 cercariae, fed with high (20%) or low-protein (5%) diets and compared to uninfected controls under the same conditions. Mice were sacrificed 12 weeks after infection. Animals submitted to a low-protein diet showed lower weight curves, mainly when infected. In the jejunal mucosa, finger-like villi were the predominant pattern among uninfected high-protein fed animals, while the infected ones showed leaf-shaped and flattened villi in most cases. Undernourished infected mice had 65.7% leaf-shaped villi. A significant increase in the number of goblet cells was seen in infected mice. A decrease in the number of absorptive cells was detected in undernourished mice, particularly in infected ones.

Blood feeding patterns of Nyssomyia intermedia and Nyssomyia neivai (Diptera, Psychodidae) in a cutaneous leishmaniasis endemic area of the Ribeira Valley, State of São Paulo, Brazil

Introduction The aim of this study was to identify the blood feeding sources of Nyssomyia intermedia (Ny. intermedia) and Nyssomyia neivai (Ny. neivai), which are Leishmania vectors and the predominant sandfly species in the Ribeira Valley, State of São Paulo, Brazil, an endemic area for cutaneous leishmaniasis. Methods Specimens were captured monthly between February 2001 and December 2003 on a smallholding and a small farm situated in the Serra district in the Iporanga municipality. The blood meals of 988 engorged females were tested using the avidin-biotin immunoenzymatic enzyme-linked immunosorbent assay (ELISA). Seven blood meal sources were investigated: human, dog, chicken, bovine, pig, horse and rat. Results The results showed that among the females that fed on one or more blood sources, the respective percentages for Ny. intermedia and Ny. neivai, respectively, were as follows: human (23% and 36.8%), pig (47.4% and 26.4%), chicken (25.7% and 36.8%) and dog (3.9% and 0%), and the differences in the blood sources between the two species were statistically significant (p = 0.043). Conclusions Both species had predominant reactivity for one or two blood sources, and few showed reactivity indicating three or four sources. Many different combinations were observed among the females that showed reactivity for more than one source, which indicated their opportunistic habits and eclecticism regarding anthropic environmental conditions.

Physiological responses of matrinxã (Brycon amazonicus) fed different levels of vitamin C and submitted to air exposure

The role of vitamin C on physiological responses of matrinxã (Brycon amazonicus) submitted to air exposure was analyzed. Nine hundred fish (70.15 g) were distributed in fifteen 500 l boxes (60 fish.box-1) and fed five rations (treatments): Control (no vitamin C); T100 (100 mg); T200 (200 mg); T400 (400 mg) and T800 (800 mg of vitamin C kg.ration-1). Each ration was offered to fish of three boxes during 60 days before the stress challenge that consisted of exposing fish to air for two minutes. Samplings were carried out for 5, 15, 30 and 60 minutes after the air exposure. Blood was collected for glucose, cortisol, total protein, sodium, chloride, hematocrit, hemoglobin determination, and white and red cell count. Liver was removed for hepatosomatic index (HSI) calculation and glycogen determination. Vitamin C did not affect the levels of cortisol, chloride, total protein, hemoglobin, leukocytes, hepatic glycogen or HSI in air exposed fish. Blood glucose levels elevation observed 60 minutes after the challenge did not depend on the levels of vitamin C, nor did the drop in serum sodium levels verified 60 minutes after stressor. In general, hematocrit did not change by effect of vitamin C but it was lower at 15 and 30 minutes after the challenge. The number of erythrocytes decreased in fish after 5 minute sampling in all treatments, especially at 30 and 60 minutes. The air exposure evoked alterations in stress indicators of matrinxã, and the vitamin C did not alter the responses.

Optimum dietary protein requirement for Amazonian Tambaqui, Colossoma macropomum Cuvier, 1818, fed fish meal free diets

Fish meal free diets were formulated to contain graded protein levels as 25% (diet 1), 30% (diet 2), 35% (diet 3) and 40% (diet 4). The diets were fed to tambaqui juveniles (Colossoma macropomum) (46.4 ± 6.3g) in randomly designed recirculating systems for 60 days, to determine the optimum protein requirement for the fish. The final weight of the fish, weight gain (28.1, 28.5, 32.2, 28.0g) and specific growth rate increased (P>0.05) consistently with increasing dietary protein up to treatment with 35% protein diet and then showed a declining trend. Feed intake followed the same trend resulting in best feed efficiency (62.5%) in fish fed diet with 35% protein. Similarly, the protein intake increased significantly with increasing dietary protein levels and reduced after the fish fed with 35% protein; while protein efficiency ratio (2.28, 1.99, 1.87, 1.74) decreased with increasing dietary protein levels. Carcass ash and protein had linear relationship with dietary protein levels while the lipid showed a decreasing trend. Ammonia content (0.68, 0.73, 0.81, 1.21 mg L-1) of the experimental waters also increased (P<0.05) with increasing protein levels while pH, dissolved oxygen and temperature remained fairly constant without any clear pattern of inclination. Broken-line estimation of the weight gain indicated 30% protein as the optimum requirement for the fish.

Hematological responses of tambaqui Colossoma macropomum (Serrassalmidae) fed with diets supplemented with essential oil from Mentha piperita (Lamiaceae) and challenged with Aeromonas hydrophila

ABSTRACTIn fish farmings, diseases can be reduced by using immunostimulants. The aim of this study was to evaluate the immunostimulant potential of Mentha piperita in tambaqui fed with 0, 0.5, 1.0 and 1.5% of oil per kg of commercial fish feed. The fish were inoculated with Aeromonas hydrophila to challenge them. Hematological and biochemical parameters were determined after 30 days of feeding and seven days after the challenge. There was no mortality and M. piperita oil did not influence fish production parameters. However, blood hemoglobin concentration (Hb) increased in the fish fed with 0.5 and 1.5% of oil per kg of diet; albumin increased in those fed with 1.0%; cholesterol increased in all groups with oil; and triglycerides increased in those fed with 0.5%. After the bacterial challenge, the fish showed decreases in Hb when fed with diet enriched with 1.5% oil per kg of diet, in mean corpuscular volume with 1.0% and in mean corpuscular hemoglobin concentration with 0 and 1.5%. Protein levels increased in groups with 0 and 1.5% of oil and albumin when fed with 0 and 1.0%; cholesterol levels increased in the control group; and high levels of triglycerides were observed in the groups with 0, 0.5 and 1.5%. Thus, M. piperita essential oil promoted hematological alterations in tambaqui and can be recommended in diets containing up to 1.0% per kg, because of the minimal physiological modifications caused. However, additional studies are necessary to obtain more information regarding to the physiological effects of this immunostimulant.

Mitral valve repair with a malleable bovine pericardium ring

OBJECTIVE: To describe a surgical procedure utilizing a malleable bovine pericardium ring in mitral valve repair and clinical and echodopplercadiographic results. METHODS: Thirty-two (25 female and 7 male) patients, aged between 9 and 66 (M=36.4±17.2) years, were studied over a 16-month period, with 100% follow-up. In 23 (72%) of the patients, the mitral approach was the only one applied; 9 patients underwent associated operations. The technique applied consisted of measuring the perimeter of the anterior leaflet and implanting, according to this measurement, a flexible bovine pericardium prosthesis for reinforcement and conformation of the posterior mitral annulus, reducing it to the perimeter of the anterior leaflet with adjustment of the valve apparatus. RESULTS: The patient survival ratio was 93.8%, with 2 (6.2%) fatal outcomes, one from unknown causes, the other due to left ventricular failure. Only one reoperation was performed. On echodopplercardiography, 88% of the patients had functional recovery of the mitral valve (50% without and 38% with mild insufficiency and no hemodynamic repercussions). Of four (12%) of the remaining patients, 6% had moderate and 6% had seigre insufficiency. Twenty-eight percent of class II patients and 72% of class III patients passed into classes I (65%), II (32%), and III (3%), according to NYHA classification criteria. CONCLUSION: Being flexible, the bovine pericardium ring fit perfectly into the valve annulus, taking into account its geometry and contractility. Valve repair was shown to be reproducible, demonstrating significant advantages during patient evolution, which did not require anticoagulation measures.

Lipid metabolism in rats fed diets containing different types of lipids

OBJECTIVE: To assess the effect of different types of lipid diets on the lipid metabolism of aging rats. METHODS: Fifty male Wistar rats were studied from the time of weaning to 12 and 18 months of age. Their diets were supplemented as follows: with soybean oil (S), canola oil (CA), lard and egg yolk (LE), and canola oil + lard and egg yolk (CA + LE). Blood pressure (BP) was measured every month, and the heart/body ratio (H/BR) was determined. The rats were euthanized at the age of 12 and 18 months, and blood samples were collected for lipid analysis as follows: total cholesterol (TC), LDL-C, VLDL-C, HDL-C, triglycerides (TG), and glucose. RESULTS: The type of oil ingested by the animals significantly altered BP, H/BR, and serum lipid levels in rats at 12 and 18 months. No difference was observed in the survival curve of the animals in the different groups. The LE group had the highest BP, and the CA group was the only one in which BP did not change with aging. A reduction in the H/BR was observed in the LE and CA+LE animals. At the age of 12 months, differences in TC, HDL-C, LDL-C, VLDL-C, TG, and glucose were observed. At the age of 18 months, a significant difference in TC, HDL-C, and glucose was observed. The highest TC value was found in the CA group and the lowest in the S group. CONCLUSION: No increase in BP occurred, and an improvement was evident in the lipid profile of rats fed a diet supplemented with CA, in which an elevation in HDL-C levels was observed, as compared with levels with the other types of diet.

Performance of Anastrepha obliqua (Diptera, Tephritidae) larvae fed on artificial diets

Moscas das frutas do gênero Anastrepha Schiner, 1868 são conhecidas por sua importância econômica devido aos danos que elas causam nos frutos comerciais. As exigências nutricionais dos estágios imaturo e adulto são diferentes e as larvas não se desenvolvem bem utilizando a mesma dieta do adulto. Embora as necessidades nutricionais básicas dos insetos sejam bem conhecidas, existe ainda o problema de elaborar dietas de criação adequadas para espécies com necessidades específicas. O objetivo deste trabalho foi verificar o efeito de diferentes tipos e quantidades de carboidratos na dieta sobre a performance larval de Anastrepha obliqua (Macquart, 1835). Larvas foram criadas individualmente em tubos de ensaio contendo uma das dietas artificiais a serem testadas onde elas foram mantidas até a pupação. A composição básica das dietas testadas incluia 2,5 g de agar, 3,25 g de levedo de cerveja e quantidades variadas de sacarose e farinha de trigo. A adequação do meio artificial para A. obliqua foi testada pela avaliação da sobrevivência larval e pupal (%) e o tempo de desenvolvimento larval, pupal e de larva-adulto. A dieta contendo farinha de trigo (2 g) e sacarose (2 g) e a dieta somente com sacarose (5,5 g) foram as que apresentaram melhor performance larval. Todas as dietas testadas apresentaram resultados similares ou superiores às dietas utilizadas em outros trabalhos. A importância da presença da farinha de trigo e seu valor nutricional para as larvas são discutidos.

Flagellates in the Malpighian tubules of laboratory-bred Lutzomyia longipalpis fed on a hamster experimentally infected with Leishmania mexicana amazonensis

As a preparatory stage for a study aiming at identifying the species and subspecies of local Leishmania in naturally infected sandflies through immunoradiometric assay with monoclonal antibodies, we tried to obtain experimental infections of phlebotomines with well characterized stocks of parasites, in order to test the effectiveness of the method.

Experimental infection of Lutzomyia longipalpis fed on a patient with cutaneous leishmaniasis due to Leishmania mexicana amazonensis

The authors were able to infect phlebotomine sandflies on a human case of American Cutaneous Leishmaniasis by feeding females of Lutzomyia longipalpis on a patient with a lesion due to Leishmania mexicana amazonensis.

Infection of Anopheles darlingi fed on patients infected with Plasmodium vivax before and during treatment with chloroquine plus primaquine in Costa Marques, Rondônia, Brazil

Five patients with asexual and sexual parasites of Plasmodium vivax were treated orally with 600 mg chloroquine diphosphate (hour 0) followed with 300 mg at 8, 24 and 48 h later. Primaquine phospate, 15 mg, was administered concurrently at h 0 and 24 h intervals for 14 days. Anopheles darlingi were fed before the first dose (h-0.5) and 0.5, 1, 2, 4, 6, 8, 10, 12, 16, 20, 24, 36, 48, 60 and 72 h later. Mosquitoes were examined for oocysts on day 8 and for sporozoites on day 15 after infection. Four of the five patients studied were still infective to mosquitoes from 1-5 h after the first dose of chloroquine plus primaquine. One of these and one other patient, who vomited 15 min after the first dose, became inffective again at hours 10 and 12, respectively. Once produced, oocysts in mosquitoes fed on patients before, during and after chloroquine plus primaquine treatment appeared normal and produced sporozoite infected salivary glands. In view of these data , it is concluded that primaquine demonstrated rapid gametocytocidal activity and should be administred concurrently with chloroquine to reduce vivax malaria transmission.

Extrachromosomal nucleic acids in bovine babesia

Two kinds of small extrachromosomal nucleic acid elements were found in the bovine babesias, Babesia bovis and B. bigemina. One element with an apparent size of 5.5 kilobase pairs (kbp) is a double stranded RNA related to virus like particles. Another molecule is a double stranded DNA with a molecular size of about 6.2 kbp. Southern blot comparison of restriction DNA fragments of the latter molecule, which is present in both B. bovis and B. bigemina is described.

Development of a vaccine strategy against human and bovine schistosomiasis: background and update

Schistosomiasis is a chronic and debilitating parasitic disease that affects over 200 million people throughout the world and causes about 500,000 deaths annually. Two specific characteristics of schistosome infection are of primordial importance to the development of a vaccine: schistosomes do not multiply within the tissues of their definitive hosts (unlike protozoan parasites) and a partial non-sterilizing immunity can have a marked effect on the incidence of pathology and on disease transmission. Since viable eggs are the cause of disease pathology, a reduction in worm fecundity whether or not accompanied by a reduction in parasite burden is a sufficient goal for vaccine induced immunity. We originally showed that IgE antibodies played in experimental models a pivotal role for the development of protective immunity. These laboratory findings have been now confirmed in human populations. Following the molecular cloning and expression of a protein 28 kDa protein of Schistosoma mansoni and its identification as a glutathion S-transferase, immunization experiments have been undertaken in several animal species (rats, mice, baboons). Together with a significant reduction in parasite burden, vaccination with Sm28 GST was recently shown to reduce significantly parasite fecundity and egg viability leading to a decrease in liver pathology. Whereas IgE antibodies were shown to be correlated with protection against infection, IgA antibodies have been identified as one of the factors affecting egg laying and viability. In human populations, a close association was found between IgA antibody production to Sm28 GST and the decrease of egg output. The use of appropriate monoclonal antibody probes has allowed the demonstration that the inhibition of parasite fecundity following immunization was related to the inhibition of enzymatic activity of the molecule. Epitope mapping of Sm28 GST has indicated the prominent role of the N and C terminal domains. Immunization with the corresponding synthetic peptides was followed by a decrease of 70% of parasite fecundity and egg viability. As a preliminary step towards phase I human trials, vaccination experiments have been performed in cattle, a natural model for Schistosoma bovis. Vaccination of calves with the S. bovis GST has led to a reduction of ever 80% of egg output and tissue egg count. Significant levels of protection were also observed in goats after immunization with the recombinant S. bovis GST. Increasing evidence of the participation of IgA antibodies in protective immunity has prompted us toward the development of mucosal immunization. Preliminary results indicate that significant levels of protection can be achieved following oral immunization with live attenuated vectors or liposomes. These studies seem to represent a promising approach towards the future development of a vaccine strategy against one of major human parasitic diseases.