RESUMEN

Lactobacillus delbrueckii UFV-H2b20 has been shown to increase clearance of bacteria injected into the blood of germ-free mice. Moreover, it induces the production of type 1 cytokines by human peripheral mononuclear cells. The objective of the present study was to investigate the production of inflammatory cytokines [interleukin-12 (IL-12 p40), tumor necrosis factor-α (TNF-α), and interferon-γ (IFN-γ)] triggered in vitro by live, heat-killed or lysozyme-treated L. delbrueckii UFV-H2b20 and in vivo by a live preparation. Germ-free, L. delbrueckii-monoassociated and lipopolysaccharide (LPS)-resistant C3H/HeJ mice were used as experimental models. UFV-H2b20 induced the production of IL-12 p40 and TNF-α by peritoneal cells and IFN-γ by spleen cells from germ-free or monoassociated Swiss/NIH mice and LPS-hyporesponsive mice (around 40 ng/mL for IL-12 p40, 200 pg/mL for TNF-α and 10 ng/mL for IFN-γ). Heat treatment of L. delbrueckii did not affect the production of these cytokines. Lysozyme treatment decreased IL-12 p40 production by peritoneal cells from C3H/HeJ mice, but did not affect TNF-α production by these cells or IFN-γ production by spleen cells from the same mouse strain. TNF-α production by peritoneal cells from Swiss/NIH L. delbrueckii-monoassociated mice was inhibited by lysozyme treatment. When testing IL-12 p40 and IFN-γ levels in sera from germ-free or monoassociated Swiss/NIH mice systemically challenged with Escherichia coli we observed that IL-12 p40 was produced at marginally higher levels by monoassociated mice than by germ-free mice (40 vs 60 ng/mL), but IFN-γ was produced earlier and at higher levels by monoassociated mice (monoassociated 4 and 14 ng/mL 4 and 8 h after infection, germfree 0 and 7.5 ng/mL at the same times). These results show that L. delbrueckii UFV-H2b20 stimulates the production of type 1 cytokines in vitro and in vivo, therefore suggesting...

Asunto(s)

Animales , Ratones , Interferón gamma/biosíntesis , /biosíntesis , Lactobacillus delbrueckii/inmunología , Macrófagos Peritoneales/inmunología , Factor de Necrosis Tumoral alfa/biosíntesis , Escherichia coli/inmunología , Vida Libre de Gérmenes/inmunología , Macrófagos Peritoneales/microbiología

RESUMEN

Lactobacillus delbrueckii UFV-H2b20 has been shown to increase clearance of bacteria injected into the blood of germ-free mice. Moreover, it induces the production of type 1 cytokines by human peripheral mononuclear cells. The objective of the present study was to investigate the production of inflammatory cytokines [interleukin-12 (IL-12 p40), tumor necrosis factor-alpha (TNF-alpha), and interferon-gamma (IFN-gamma)] triggered in vitro by live, heat-killed or lysozyme-treated L. delbrueckii UFV-H2b20 and in vivo by a live preparation. Germ-free, L. delbrueckii-monoassociated and lipopolysaccharide (LPS)-resistant C3H/HeJ mice were used as experimental models. UFV-H2b20 induced the production of IL-12 p40 and TNF-alpha by peritoneal cells and IFN-gamma by spleen cells from germ-free or monoassociated Swiss/NIH mice and LPS-hyporesponsive mice (around 40 ng/mL for IL-12 p40, 200 pg/mL for TNF-alpha and 10 ng/mL for IFN-gamma). Heat treatment of L. delbrueckii did not affect the production of these cytokines. Lysozyme treatment decreased IL-12 p40 production by peritoneal cells from C3H/HeJ mice, but did not affect TNF-alpha production by these cells or IFN-gamma production by spleen cells from the same mouse strain. TNF-alpha production by peritoneal cells from Swiss/NIH L. delbrueckii-monoassociated mice was inhibited by lysozyme treatment. When testing IL-12 p40 and IFN-gamma levels in sera from germ-free or monoassociated Swiss/NIH mice systemically challenged with Escherichia coli we observed that IL-12 p40 was produced at marginally higher levels by monoassociated mice than by germ-free mice (40 vs 60 ng/mL), but IFN-gamma was produced earlier and at higher levels by monoassociated mice (monoassociated 4 and 14 ng/mL 4 and 8 h after infection, germfree 0 and 7.5 ng/mL at the same times). These results show that L. delbrueckii UFV-H2b20 stimulates the production of type 1 cytokines in vitro and in vivo, therefore suggesting that L. delbrueckii might have adjuvant properties in infection in which these cytokines play a major role.

Asunto(s)

Interferón gamma/biosíntesis , Interleucina-12/biosíntesis , Lactobacillus delbrueckii/inmunología , Macrófagos Peritoneales/inmunología , Factor de Necrosis Tumoral alfa/biosíntesis , Animales , Escherichia coli/inmunología , Vida Libre de Gérmenes/inmunología , Macrófagos Peritoneales/microbiología , Ratones , Ratones Endogámicos C3H

RESUMEN

In order to investigate the importance of the host microbiota on differentiation of T cell subsets in response to infection, Swiss/NIH germ-free mice and conventional (microbiota-bearing) mice were infected with Leishmania major, and lesion development, parasite loads, and cytokine production were assessed. Germ-free mice failed to heal lesions and presented a higher number of parasites at the site of infection than their conventional counterparts. In addition, histopathological analysis indicated a higher density of parasitized macrophages in lesions from germ-free mice than in conventional mice. The initial production of interleukin (IL)-12 and interferon-gamma (IFN-gamma) in germ-free mice was comparable to the conventional controls. Also, germ-free mice produced elevated levels of IFN-gamma and lower levels of IL-4 throughout the course of infection, suggesting the development of a Th1 response. Macrophages from germ-free mice exposed to IFN-gamma and infected with amastigotes in vitro were not as efficient at killing parasites as macrophages from conventional animals. These observations indicate that the microbiota is not essential for the development of Th1 immune responses, but seems to be important for macrophage activation.

Asunto(s)

Citocinas/biosíntesis , Interferón gamma/biosíntesis , Leishmania major , Leishmaniasis Cutánea/patología , Células TH1/microbiología , Animales , Técnicas de Cultivo de Célula , Citocinas/análisis , Modelos Animales de Enfermedad , Femenino , Vida Libre de Gérmenes , Interferón gamma/análisis , Leishmaniasis Cutánea/inmunología , Leishmaniasis Cutánea/microbiología , Activación de Macrófagos/inmunología , Ratones , Células TH1/inmunología

RESUMEN

Although the role of oxidized lipoproteins is well known in atherogenesis, the role of vitamin E supplementation is still controversial. There is also little information about cholesterol metabolism (hepatic concentration and fecal excretion) in the new models of atherosclerosis. In the present study, we evaluated the effect of moderate vitamin E supplementation on cholesterol metabolism and atherogenesis in apolipoprotein E (apo E)-deficient mice. Apo E-deficient mice were fed an atherogenic diet containing 40 or 400 mg/kg of alpha-tocopherol acetate for 6 weeks. Total cholesterol in serum and liver and 3-OH-alpha-sterols in feces, and fecal excretion of bile acids were determined and histological analyses of aortic lesion were performed. A vitamin E-rich diet did not affect body weight, food intake or serum cholesterol. Serum and hepatic concentrations of cholesterol as well as sterol concentration in feces were similar in both groups. However, when compared to controls, the alpha-tocopherol-treated mice showed a reduction of about 60 percent in the atherosclerotic lesions when both the sum of lesion areas and the average of the largest lesion area were considered. These results demonstrate that supplementation of moderate doses of alpha-tocopherol was able to slow atherogenesis in apo E-deficient mice and to reduce atherogenic lipoproteins without modifying the hepatic pool or fecal excretion of cholesterol and bile acids

Asunto(s)

Animales , Ratones , Antioxidantes , Apolipoproteínas E , Colesterol , Dieta Aterogénica , Vitamina E , Aorta , Ácidos y Sales Biliares , Peso Corporal , Colesterol , Heces , Hígado , Ratones Endogámicos C57BL

RESUMEN

Although the role of oxidized lipoproteins is well known in atherogenesis, the role of vitamin E supplementation is still controversial. There is also little information about cholesterol metabolism (hepatic concentration and fecal excretion) in the new models of atherosclerosis. In the present study, we evaluated the effect of moderate vitamin E supplementation on cholesterol metabolism and atherogenesis in apolipoprotein E (apo E)-deficient mice. Apo E-deficient mice were fed an atherogenic diet containing 40 or 400 mg/kg of alpha-tocopherol acetate for 6 weeks. Total cholesterol in serum and liver and 3-OH-alpha-sterols in feces, and fecal excretion of bile acids were determined and histological analyses of aortic lesion were performed. A vitamin E-rich diet did not affect body weight, food intake or serum cholesterol. Serum and hepatic concentrations of cholesterol as well as sterol concentration in feces were similar in both groups. However, when compared to controls, the alpha-tocopherol-treated mice showed a reduction of about 60% in the atherosclerotic lesions when both the sum of lesion areas and the average of the largest lesion area were considered. These results demonstrate that supplementation of moderate doses of alpha-tocopherol was able to slow atherogenesis in apo E-deficient mice and to reduce atherogenic lipoproteins without modifying the hepatic pool or fecal excretion of cholesterol and bile acids.

Asunto(s)

Antioxidantes/administración & dosificación , Apolipoproteínas E/deficiencia , Arteriosclerosis/etiología , Colesterol/metabolismo , Dieta Aterogénica , alfa-Tocoferol/administración & dosificación , Animales , Enfermedades de la Aorta/etiología , Ácidos y Sales Biliares/análisis , Peso Corporal , Colesterol/análisis , Heces/química , Hígado/química , Ratones , Ratones Endogámicos C57BL

RESUMEN

BACKGROUND: This study was carried out to determine whether early inoculation of the plasmid-free human Escherichia coli into human newborns would reduce the frequency of acute diarrhea during a 1-year period. The plasmid-free E. coli strain isolated from the fecal microbiota of a healthy adult was nontoxigenic in vivo and in vitro and sensitive to all usual antibiotics. METHODS: In the experimental group, 51 healthy newborns were inoculated orally with 106 viable cells of the bacteria within 2 hours after birth. In the control group, the same number of newborns received the heat-killed bacteria. The clinical trial was double blind, and the newborns were randomly assigned to the experimental and control groups. RESULTS: Six months and 1 year after bacterial inoculation, infants in the experimental group showed a higher mean body weight (7.59 +/- 1.15 kg and 9.88 +/- 1.31 kg, respectively; P < 0.05) when compared with the control group (7.03 +/- 1.09 kg and 8.92 +/- 1.38 kg, respectively). At the end of the clinical trial, 48% (23/48) of the infants in the experimental group had shown at least one diarrhea episode during the 1-year period, as opposed to 71% (34/48) in the control group. These values were significantly different (P = 0.037), showing a 32.3% protective effect of inoculation. CONCLUSIONS: The present study shows that protection against diarrhea was obtained by oral inoculation with a single dose of plasmid-free human E. coli soon after birth.

Asunto(s)

Diarrea Infantil/prevención & control , Infecciones por Escherichia coli/prevención & control , Escherichia coli , Plásmidos , Administración Oral , Peso Corporal , Diarrea Infantil/epidemiología , Método Doble Ciego , Infecciones por Escherichia coli/epidemiología , Heces/microbiología , Femenino , Humanos , Incidencia , Lactante , Recién Nacido , Masculino

RESUMEN

High protein content in the diet during childhood and adolescence has been associated to the onset insulin-dependent diabetes mellitus. We investigated the effect of interleukin-1beta (IL-1beta) on insulin secretion, glucose metabolism, and nitrite formation by islets isolated from rats fed with normal protein (NP, 17%) or low protein (LP, 6%) after weaning. Pretreatment of islets with IL-1beta for 1 h or 24 h inhibited the insulin secretion induced by glucose in both groups, but it was less marked in LP than in NP group. Islets from LP rats exhibited a decreased IL-1beta-induced nitric oxide (NO) production, lower inhibition of D-[U(14)C]-glucose oxidation to (14)CO(2) and less pronounced effect of IL-1beta on alpha-ketoisocaproic acid-induced insulin secretion than NP islets. However, when the islets were stimulated by high concentrations of K(+) the inhibitory effect of IL-1beta on insulin secretion was not different between groups. In conclusion, protein restriction protects beta-cells of the deleterious effect of IL-1beta, apparently, by decreasing NO production. The lower NO generation in islets from protein deprived rats may be due to increased free fatty acids oxidation and consequent alteration in Ca(2+) homeostasis.

RESUMEN

The effect of gelatin ingestion on cholesterol metabolism and on atheroma formation was evaluated in both wild type (n=14) and apoprotein E (apoE) knock out (apoE(-/-)) (n=20) C57BL/6 7-week-old mice. Animals were fed a cholesterol-free isoproteic semi-purified diet containing 20% of casein (control diet) or 10% of casein plus 10% of gelatin (gel diet) for 8 weeks. In wild type mice, dietary gelatin caused a reduction in the serum triacylglycerols levels associated with an increase in the fecal excretion. No difference in blood cholesterol was seen at the sixth week of experiment. At the eighth week of experiment, there was a modest but significant reduction of serum total and high density lipoprotein (HDL) cholesterol in apoE(-/-) mice fed on gel diet compared to the control. Total cholesterol/HDL cholesterol ratio was 2-fold higher in the gel group than that seen in the control group (14.39 and 7.84, respectively). Histological analyzes showed a 2.2-fold increase in the dimension of the atherosclerotic plaques in the proximal aorta in apoE(-/-) mice fed on a gel diet compared to those fed on a control diet. The gel diet also promoted a reduction in the fecal excretion of bile acids. Hepatic cholesterol was similar in both groups. In conclusion, although gelatin reduced total serum cholesterol, this reduction was associated to a decrease of HDL cholesterol and consequent increase of total cholesterol/HDL cholesterol ratio, resulting in an acceleration of atherogenesis.

Asunto(s)

Apolipoproteínas E/deficiencia , Arteriosclerosis/etiología , Gelatina/administración & dosificación , Animales , Aorta/efectos de los fármacos , Aorta/patología , Apolipoproteínas E/genética , Arteriosclerosis/patología , Caseínas/administración & dosificación , Caseínas/farmacología , Colesterol/sangre , HDL-Colesterol/antagonistas & inhibidores , HDL-Colesterol/sangre , Dieta , Femenino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados/genética , Farmacología

RESUMEN

The effect of Saccharomyces boulardii on the immune system was evaluated, comparing germ-free Swiss/NIH mice monoassociated with the probiotic with germ-free mice. Saccharomyces boulardii colonized the gut of germ-free mice and survived the gastrointestinal conditions. An increase in sIgA production, both total and anti-S. boulardii, was observed in the intestinal contents of monoassociated mice when compared with germ-free controls. The number of Kupffer cells was significantly higher in monoassociated mice than in germ-free controls. In S. boulardii-monoassociated mice, clearance of Escherichia coli B41 was higher than in germ-free controls. TNF-alpha, IFN-gamma and IL-12 serum levels were higher at earlier time points in monoassociated mice when compared with germ-free mice. These results show that the yeast S. boulardii modulates the host immune responses. This effect may be of interest for improving the resistance to enteropathogenic bacterial infections.

Asunto(s)

Anticuerpos Antifúngicos/inmunología , Inmunoglobulina A/inmunología , Saccharomyces , Animales , Anticuerpos Antifúngicos/análisis , Recuento de Células , Femenino , Inmunoglobulina A/análisis , Interferón gamma/análisis , Interleucina-12/sangre , Intestino Delgado/inmunología , Macrófagos del Hígado/citología , Masculino , Ratones , Fagocitosis , Organismos Libres de Patógenos Específicos , Factor de Necrosis Tumoral alfa/análisis

RESUMEN

Eggplant (Solanum melongena) is consumed extensively in Brazil. It has been believed that infusion of a powdered preparation of the fruit may reduce serum cholesterol. However, there are few documented reports on its effects on cholesterol metabolism and its possible hypocholesterolemic effect has not been proved by well-controlled studies. The aim of the present study was to observe the effects of S. melongena on the serum cholesterol and triglycerides of 38 hypercholesterolemic human volunteers ingesting S. melongena infusion for five weeks. Thirty-eight hypercholesterolemic subjects receiving either S. melongena infusion (N = 19) or placebo (N = 19) participated in two clinical experiments in which the effect of S. melongena infusion was studied with (N = 16) or without (N = 38) dietary orientation. Total cholesterol and its fractions, triglycerides, and apolipoproteins A and B were measured in blood at the beginning of the experiment and three and five weeks thereafter. No differences were observed compared to control. Intraindividual analysis showed that S. melongena infusion significantly reduced the blood levels of total and LDL cholesterol and of apolipoprotein B. After dietary orientation, no intra- or intergroup differences were seen for any of the parameters analyzed. The results suggest that S. melongena infusion had a modest and transitory effect, which was not different from that obtained with standard orientation for dyslipidemia patients (diet and physical activities).

Asunto(s)

Colesterol/sangre , Hipercolesterolemia/terapia , Fitoterapia , Extractos Vegetales/uso terapéutico , Triglicéridos/sangre , Verduras/uso terapéutico , Adulto , Estudios de Casos y Controles , HDL-Colesterol/sangre , LDL-Colesterol/sangre , VLDL-Colesterol/sangre , Método Doble Ciego , Femenino , Humanos , Hipercolesterolemia/sangre , Masculino , Persona de Mediana Edad , Extractos Vegetales/química , Verduras/química

RESUMEN

Eggplant (Solanum melongena) is consumed extensively in Brazil. It has been believed that infusion of a powdered preparation of the fruit may reduce serum cholesterol. However, there are few documented reports on its effects on cholesterol metabolism and its possible hypocholesterolemic effect has not been proved by well-controlled studies. The aim of the present study was to observe the effects of S. melongena on the serum cholesterol and triglycerides of 38 hypercholesterolemic human volunteers ingesting S. melongena infusion for five weeks. Thirty-eight hypercholesterolemic subjects receiving either S. melongena infusion (N = 19) or placebo (N = 19) participated in two clinical experiments in which the effect of S. melongena infusion was studied with (N = 16) or without (N = 38) dietary orientation. Total cholesterol and its fractions, triglycerides, and apolipoproteins A and B were measured in blood at the beginning of the experiment and three and five weeks thereafter. No differences were observed compared to control. Intraindividual analysis showed that S. melongena infusion significantly reduced the blood levels of total and LDL cholesterol and of apolipoprotein B. After dietary orientation, no intra- or intergroup differences were seen for any of the parameters analyzed. The results suggest that S. melongena infusion had a modest and transitory effect, which was not different from that obtained with standard orientation for dyslipidemia patients (diet and physi

Asunto(s)

Humanos , Adulto , Persona de Mediana Edad , Masculino , Femenino , Colesterol/sangre , Hipercolesterolemia/terapia , Extractos Vegetales/uso terapéutico , Plantas/uso terapéutico , Estudios de Casos y Controles , HDL-Colesterol/sangre , LDL-Colesterol/sangre , VLDL-Colesterol/sangre , Método Doble Ciego , Hipercolesterolemia/sangre , Extractos Vegetales/química , Plantas/química

RESUMEN

Lactobacillus acidophilus, Saccharomyces boulardii and Escherichia coli are probiotic strains used individually to protect against enteropathogenic agents. In order to determine if a synergistic effect of the individual protective mechanisms ordinarily attributed to each of these biotherapeutic agents is possible, we orally administered Lact. acidophilus H2B20, S. boulardii and E. coli EMO (LSE) to germfree mice. Ten days after colonization of the digestive tract, groups of animals associated (experimental) or not (control) with LSE were challenged orally with streptomycin resistant (Sfr) or streptomycin sensitive (Sfs) Shigella flexneri strains or Salmonella enteritidis subsp. typhimurium. Bacterial counts in faeces from experimental mice showed that the Sfr strain was eliminated 11 d after challenge while Sfs and S. enteritidis subsp. typhimurium colonized the digestive tract and continued to be present at high population levels (108 CFU g-1 of faeces), which is similar to that observed in control animals. All possible di- and monoassociations of the three probiotics with gnotobiotic mice were also performed before experimental oral infection with Sfr. The data showed that antagonism was obtained only when E. coli EMO was present. Different sensitivity of Sh. flexneri Sfr and Sfs to E. coli EMO antagonism could be explained by the different generation times between Sfr and Sfs, as shown by colonization kinetic experiments in the digestive tract of gnotobiotic mice.

Asunto(s)

Infecciones por Enterobacteriaceae/microbiología , Enterobacteriaceae/crecimiento & desarrollo , Escherichia coli/crecimiento & desarrollo , Lactobacillus acidophilus/crecimiento & desarrollo , Probióticos , Saccharomyces/crecimiento & desarrollo , Animales , Antibiosis , Recuento de Colonia Microbiana , Disentería Bacilar/microbiología , Disentería Bacilar/prevención & control , Infecciones por Enterobacteriaceae/prevención & control , Heces/microbiología , Vida Libre de Gérmenes , Ratones , Salmonelosis Animal/microbiología , Salmonelosis Animal/prevención & control , Salmonella typhimurium/crecimiento & desarrollo , Shigella flexneri/crecimiento & desarrollo

RESUMEN

The heat shock response has imparted protective effects in animal models of septic shock and endotoxemia. This study has tested the hypothesis that it could be protective in experimental burns. One hundred and fifteen adult male Fischer rats were randomly divided into four groups. Rats in the first group (n = 12) were anesthetized and shaved. In the second group (n = 15) rats were anesthetized and heated in a 45 degrees C water bath. In the third group (n = 44), rats were anesthetized, shaved and submitted to 26-30% body surface third-degree burns using a brass bar. In the fourth group (n = 44), rats were anesthetized, heated and, 1 day after, they were burnt. Mortality rates were measured at 3, 7, 15 and 25 days. Liver and lung samples were collected from all groups for heat-shock protein 70 detection. Heat-shock protein 70 was positive in heated animals. No animals died in the first or second group. Heated and burnt animals showed significantly decreased mortality at days 3 (p < 0.05, Fischer's exact test) and at days 7, 15 and 25 (p < 0.01) after burns, when compared to unheated burnt animals. In conclusion, eliciting the heat-shock response significantly reduced mortality rates in this model of experimental burns.

Asunto(s)

Quemaduras/terapia , Proteínas de Choque Térmico/análisis , Respuesta al Choque Térmico/fisiología , Calor/uso terapéutico , Animales , Quemaduras/fisiopatología , Modelos Animales de Enfermedad , Puntaje de Gravedad del Traumatismo , Masculino , Distribución Aleatoria , Ratas , Ratas Endogámicas F344 , Valores de Referencia , Análisis de Supervivencia

RESUMEN

To study the possible influence of intestinal micro-organisms on the course of strongyloidiasis in mice, a method was developed to obtain axenic infective larvae of Strongyloides venezuelensis. Cultured larvae from conventional mice were treated with sodium hypochlorite 0.25% for 10 min, washed in distilled water and then exposed to various combinations of antibiotics for 30 or 60 min. Success was achieved with a combination of penicillin 180 mg/L and ceftazidime 1 mg/ml. Decontamination of the larvae was determined by aerobic and anaerobic culture and by inoculation into gnotobiotic mice. Viability was established by subcutaneous inoculation of larvae into germ-free and conventional mice. Preliminary results showed that gnotobiotic mice were more susceptible than conventional mice to infection with axenic S. venezuelensis larvae as judged by faecal egg excretion, recovery of worms in the small intestine and histopathological examination of the duodenal mucosa. These results suggest that the normal intestinal flora protects the host against experimental infection with S. venezuelensis.

Asunto(s)

Duodeno/parasitología , Strongyloides/patogenicidad , Estrongiloidiasis/parasitología , Animales , Antibacterianos/farmacología , Desinfectantes/farmacología , Duodeno/microbiología , Duodeno/patología , Heces/parasitología , Vida Libre de Gérmenes , Larva , Ratones , Ratones Endogámicos AKR , Recuento de Huevos de Parásitos , Hipoclorito de Sodio/farmacología , Strongyloides/efectos de los fármacos , Estrongiloidiasis/inmunología

RESUMEN

Infection of Swiss/NIH mice with Leishmania major was compared with infection in isogenic resistant C57BL/6 and susceptible BALB/c mice. Swiss/NIH mice showed self-controlled lesions in the injected foot pad. The production of high levels of interferon-gamma (IFN-gamma) and low levels of interleukin-4 (IL-4) by cells from these animals suggests that they mount a Th1-type immune response. The importance of the indigenous microbiota on the development of murine leishmaniasis was investigated by infecting germfree Swiss/NIH in the hind footpad with L. major and conventionalizing after 3 weeks of infection. Lesions from conventionalized Swiss/NIH mice were significantly larger than conventional mice. Histopathological analysis of lesions from conventionalized animals showed abscesses of variable shapes and sizes and high numbers of parasitized macrophages. In the lesions from conventional mice, besides the absence of abscess formation, parasites were rarely observed. On the other hand, cells from conventional and conventionalized mice produced similar Th1-type response characterized by high levels of IFN-gamma and low levels of IL-4. In this study, we demonstrated that Swiss/NIH mice are resistant to L. major infection and that the absence of the normal microbiota at the beginning of infection significantly influenced the lesion size and the inflammatory response at the site of infection.

Asunto(s)

Leishmaniasis Cutánea/patología , Animales , Técnicas de Cultivo de Célula , Citocinas/análisis , Citocinas/biosíntesis , Modelos Animales de Enfermedad , Femenino , Vida Libre de Gérmenes , Interferón gamma/análisis , Interferón gamma/biosíntesis , Leishmaniasis Cutánea/microbiología , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Células TH1/microbiología

RESUMEN

Helicobacter spp. have been the focus of considerable research because of the role of this genus in gastrointestinal diseases. We infected NIH germ-free mice with Helicobacter trogontum, a recently described intestinal bacterium of rats, in order to study the distribution of this bacterium in the gastrointestinal tract and the histopathological changes it can induce in this host. Sixteen mice were challenged with a single dose of H. trogontum (test group) and killed one and six weeks after inoculation (eight animals at each point). Eight animals were challenged with 0.85% saline alone (control group) and killed at the same time points (four at each point). Fragments from the gastric and intestinal mucosa were obtained for microbiological and histological examination. H. trogontum was isolated from the cecum and colon of all test mice and also from the gastric mucosa of several of them. All infected animals presented histological changes in at least one region of the bowel. Alterations in the gastric mucosa were also observed mainly in the six-week-infected group. The predominant histological change observed was a moderate diffuse inflammatory infiltrate of mononuclear cells in the lamina propria, often accompanied by a mild infiltration of polymorphonuclear cells. Two animals presented focal infiltration of inflammatory cells in the liver, although no bacteria were found in the liver of any animal. H. trogontum is an intestinal species that is able to elicit inflammatory responses in other regions of the gastrointestinal tract such as the gastric mucosa and the liver of gnotobiotic mice.

Asunto(s)

Sistema Digestivo/microbiología , Enfermedades Gastrointestinales/microbiología , Infecciones por Helicobacter/microbiología , Helicobacter/aislamiento & purificación , Animales , Sistema Digestivo/patología , Femenino , Mucosa Gástrica/microbiología , Mucosa Gástrica/patología , Enfermedades Gastrointestinales/patología , Vida Libre de Gérmenes , Infecciones por Helicobacter/patología , Mucosa Intestinal/microbiología , Mucosa Intestinal/patología , Intestino Grueso/microbiología , Intestino Grueso/patología , Intestino Delgado/microbiología , Intestino Delgado/patología , Hígado/patología , Ratones , Ratas , Bazo/patología , Estómago/microbiología , Estómago/patología

RESUMEN

In germfree mice, the administration of short-chain fatty acids (SCFA) protected the intestinal mucosa from damage produced by 1-beta-D-arabinofuranosylcytosine (Ara-C). Animals receiving SCFA and Ara-C had intestinal morphologies closer to normal than the control animals, which had severe intestinal lesions. We concluded that orally administrated SCFA reduce intestinal lesions, improving the mucosa pattern of the small intestine and colon.

Asunto(s)

Citarabina/efectos adversos , Ácidos Grasos Volátiles/uso terapéutico , Enfermedades Intestinales/prevención & control , Sustancias Protectoras/uso terapéutico , Administración Oral , Animales , Modelos Animales de Enfermedad , Ácidos Grasos Volátiles/efectos adversos , Hígado Graso/inducido químicamente , Enfermedades Intestinales/inducido químicamente , Enfermedades Intestinales/patología , Mucosa Intestinal/efectos de los fármacos , Mucosa Intestinal/patología , Ratones , Sustancias Protectoras/efectos adversos

RESUMEN

Avaliaram-se os níveis de energia metabolizável normalmente utilizados nas raçöes de frangos de corte, obtidos pela inclusäo de óleos vegetais (soja, canola e palma) e seus efeitos sobre o perfil de ácidos graxos da pele e dos músculos da coxa e do peito, levando-se em consideraçäo a linhagem e o sexo. Foram utilizados 2400 pintos de um dia, machos e fêmeas, das linhagens comerciais Hubbard e Avian Farms. As aves receberam raçäo inicial e final com níveis de energia metabolízavel de 3050 e 3150kcal/kg, respectivamente, obtidos pela inclusäo dos óleos vegetais, fornecedores de ácidos graxos, inclusive "w-3". Utilizou-se um delineamento inteiramente ao acaso em um arranjo fatorial com 16 tratamentos (4 raçöes x 2 sexos x 2 linhagens) com duas repetiçöes cada. Diferenças entre médias foram testadas pela dms. Näo houve efeito significativo da inclusäo de óleos na raçäo sobre o perfil de ácidos graxos na carcaça. O mesmo ocorreu quanto ao efeito de sexo e de linhagem

Asunto(s)

Animales , Ácidos Grasos , Aceites de Plantas , Aves de Corral

RESUMEN

The ability of Bifidobacterium bifidum from a commercial bifidus milk to antagonize Salmonella enteritidis subsp. typhimurium in vivo, and to reduce the pathological consequences for the host, was determined using conventional and gnotobiotic mice. Conventional animals received daily, by gavage, 0.1 ml bifidus milk containing about 10(9) cfu B. bifidum and germ-free animals received a single 0.1 ml dose. The conventional and gnotobiotic groups were challenged orally with 10(2) cfu of the pathogenic bacteria 5 and/or 10 d after the beginning of treatment. Control groups were treated with milk. Bifidus milk protected both animal models against the challenge with the pathogenic bacteria, as demonstrated by survival and histopathological data. However, to obtain the protective effect in gnotobiotic animals, the treatment had to be initiated 10 d before the challenge. In experimental and control gnotobiotic mice, Salm. enteritidis subsp. typhimurium became similarly established at levels ranging from 10(8) to 10(9) viable cells g-1 of faeces and remained at these high levels until the animals died or were sacrificed. It was concluded that the protection against Salm. enteritidis subsp. typhimurium observed in conventional and gnotobiotic mice treated with bifidus milk was not due to the reduction of the intestinal populations of the pathogenic bacteria.

Asunto(s)

Bifidobacterium/crecimiento & desarrollo , Leche/microbiología , Probióticos , Salmonelosis Animal/prevención & control , Salmonella typhimurium/crecimiento & desarrollo , Animales , Antibiosis , Recuento de Colonia Microbiana , Heces/microbiología , Vida Libre de Gérmenes , Ratones , Salmonelosis Animal/mortalidad

RESUMEN

This work evaluated the efficacy of an improved method used to determine the frequency of bacterial infiltration and bacterial population levels and morphotypes in cavities restored with adhesive composites in conventional mice. By using the alternative methodology suggested in this work, bacteria from microleakage were recovered and identified in cavities subjected to restoration procedures that used acid etching of the dentin and dentin adhesives used with light-curing resin. The methodology presented herein seems to be more effective than the one normally used to investigate the presence of bacteria, which uses acid demineralization of dental structures for the histological processing of tissues. The results suggest that the methodology presented in this work made it possible to recover and identify Gram-negative and Gram-positive bacteria from microleakage. Frequencies of microleakage and bacterial population levels in restored cavities using two different adhesive systems were not statistically different (p < 0.05).

Asunto(s)

Técnicas Bacteriológicas , Filtración Dental/diagnóstico , Filtración Dental/microbiología , Cavidad Pulpar/microbiología , Animales , Recuento de Colonia Microbiana , Restauración Dental Permanente , Recubrimientos Dentinarios , Estudios de Evaluación como Asunto , Bacterias Gramnegativas/aislamiento & purificación , Bacterias Grampositivas/aislamiento & purificación , Ratones