Effect of cyhalothrin on Ehrlich tumor growth and macrophage activity in mice

Cyhalothrin, a pyrethroid insecticide, induces stress-like symptoms, increases c-fos immunoreactivity in the paraventricular nucleus of the hypothalamus, and decreases innate immune responses in laboratory animals. Macrophages are key elements in cellular immune responses and operate at the tumor-host interface. This study investigated the relationship among cyhalothrin effects on Ehrlich tumor growth, serum corticosterone levels and peritoneal macrophage activity in mice. Three experiments were done with 10 experimental (single gavage administration of 3.0 mg/kg cyhalothrin daily for 7 days) and 10 control (single gavage administration of 1.0 mL/kg vehicle of cyhalothrin preparation daily for 7 days) isogenic BALB/c mice in each experiment. Cyhalothrin i) increased Ehrlich ascitic tumor growth after ip administration of 5.0 x 106 tumor cells, i.e., ascitic fluid volume (control = 1.97 ± 0.39 mL and experimental = 2.71 ± 0.92 mL; P < 0.05), concentration of tumor cells/mL in the ascitic fluid (control = 111.95 ± 16.73 x 106 and experimental = 144.60 ± 33.18 x 106; P < 0.05), and total number of tumor cells in the ascitic fluid (control = 226.91 ± 43.22 x 106 and experimental = 349.40 ± 106.38 x 106; P < 0.05); ii) increased serum corticosterone levels (control = 200.0 ± 48.3 ng/mL and experimental = 420.0 ± 75.5 ng/mL; P < 0.05), and iii) decreased the intensity of macrophage phagocytosis (control = 132.3 ± 19.7 and experimental = 116.2 ± 4.6; P < 0.05) and oxidative burst (control = 173.7 ± 40.8 and experimental= 99.58 ± 41.7; P < 0.05) in vitro in the presence of Staphylococcus aureus. These data provide evidence that cyhalothrin simultaneously alters host resistance to Ehrlich tumor growth, hypothalamic-pituitary-adrenocortical (HPA) axis function, and peritoneal macrophage activity. The results are discussed in terms of data suggesting a link between stress, HPA axis activation and resistance to tumor growth.

Antipyretic and antioxidant activities of 5-trifluoromethyl-4,5-dihydro-1H-pyrazoles in rats

The objective of this study was to determine the effect of eight 5-hydroxy-5-trifluoromethyl-4,5-dihydro-1H-1-carboxyamidepyrazoles (TFDPs) on rat body temperature and baker’s yeast-induced fever. TFDPs or vehicle (5% Tween 80 in 0.9% NaCl, 5 mL/kg) were injected subcutaneously and rectal temperature was measured as a function of time in 28-day-old male Wistar rats (N = 5-12 per group). Antipyretic activity was determined in feverish animals injected with baker’s yeast (Saccharomyces cerevisiae suspension, 0.135 mg/kg, 10 mL/kg, ip). 3-Ethyl- and 3-propyl-TFDP (140 and 200 μmol/kg, respectively, 4 h after yeast injection) attenuated baker’s yeast-induced fever by 61 and 82%, respectively. These two effective antipyretics were selected for subsequent analysis of putative mechanisms of action. We then determined the effects on cyclooxygenase-1 and -2 (COX-1 and COX-2) activities on 1,1-diphenyl-2-picrylhydrazyl (DPPH) oxidation in vitro, on tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) levels and on leukocyte counts in the washes of peritoneal cavities of rats injected with baker’s yeast. While 3-ethyl- and 3-propyl-TFDP did not reduce baker’s yeast-induced increases of IL-1β or TNF-α levels, 3-ethyl-TFDP caused a 42% reduction in peritoneal leukocyte count. 3-Ethyl- and 3-propyl-TFDP did not alter COX-1 or COX-2 activities in vitro, but presented antioxidant activity in the DPPH assay with an IC50 of 39 mM (25-62) and 163 mM (136-196), respectively. The data indicate that mechanisms of action of these two novel antipyretic pyrazole derivatives do not involve the classic inhibition of the COX pathway or pyrogenic cytokine release.

Evidence for eosinophil recruitment, leukotriene B4 production and mast cell hyperplasia following Toxocara canis infection in rats

It is well known that eosinophilia is a key pathogenetic component of toxocariasis. The objective of the present study was to determine if there is an association between peritoneal and blood eosinophil influx, mast cell hyperplasia and leukotriene B4 (LTB4) production after Toxocara canis infection. Oral inoculation of 56-day-old Wistar rats (N = 5-7 per group) with 1000 embryonated eggs containing third-stage (L3) T. canis larvae led to a robust accumulation of total leukocytes in blood beginning on day 3 and peaking on day 18, mainly characterized by eosinophils and accompanied by higher serum LTB4 levels. At that time, we also noted increased eosinophil numbers in the peritoneal cavity. In addition, we observed increased peritoneal mast cell number in the peritoneal cavity, which correlated with the time course of eosinophilia during toxocariasis. We also demonstrated that mast cell hyperplasia in the intestines and lungs began soon after the T. canis larvae migrated to these compartments, reaching maximal levels on day 24, which correlated with the complete elimination of the parasite. Therefore, mast cells appear to be involved in peritoneal and blood eosinophil infiltration through an LTB4-dependent mechanism following T. canis infection in rats. Our data also demonstrate a tight association between larval migratory stages and intestinal and pulmonary mast cell hyperplasia in the toxocariasis model.

Aging alters the production of iNOS, arginase and cytokines in murine macrophages

The limited amount of information on the primary age-related deficiencies in the innate immune system led us to study the production of inducible nitric oxide synthase (iNOS), arginase, and cytokines in macrophages of young (8 weeks old) and old (72 weeks old) female BALB/c mice. We first evaluated iNOS and arginase inducers on peritoneal (PMΦ) and bone marrow-derived (BMMΦ) macrophages of young BALB/c and C57BL/6 mice, and then investigated their effects on macrophages of old mice. Upon stimulation with lipopolysaccharide (LPS), resident and thioglycolate-elicited PMΦ from young mice presented higher iNOS activity than those from old mice (54.4%). However, LPS-stimulated BMMΦ from old mice showed the highest NO levels (50.1%). Identical NO levels were produced by PMΦ and BMMΦ of both young and old mice stimulated with interferon-γ. Arginase activity was higher in resident and elicited PMΦ of young mice stimulated with LPS (48.8 and 32.7%, respectively) and in resident PMΦ stimulated with interleukin (IL)-4 (64%). BMMΦ of old mice, however, showed higher arginase activity after treatment with IL-4 (46.5%). In response to LPS, PMΦ from old mice showed the highest levels of IL-1α (772.3 ± 51.9 pg/mL), whereas, those from young mice produced the highest amounts of tumor necrosis factor (TNF)-α (937.2 ± 132.1 pg/mL). Only TNF-α was expressed in LPS-treated BMMΦ, and cells from old mice showed the highest levels of this cytokine (994.1 ± 49.42 pg/mL). Overall, these results suggest that macrophages from young and old mice respond differently to inflammatory stimuli, depending on the source and maturity of the cell donors.

Paradoxical effect of a pequi oil-rich diet on the development of atherosclerosis: balance between antioxidant and hyperlipidemic properties

Pequi is the fruit of Caryocar brasiliense and its oil has a high concentration of monounsaturated and saturated fatty acids, which are anti- and pro-atherogenic agents, respectively, and of carotenoids, which give it antioxidant properties. Our objective was to study the effect of the intake of a cholesterol-rich diet supplemented with pequi oil, compared to the same diet containing soybean oil, on atherosclerosis development, and oxidative stress in atherosclerosis-susceptible LDL receptor-deficient mice (LDLr-/-, C57BL/6-background). Female mice were fed a cholesterol-rich diet containing 7% soybean oil (Soybean group, N = 12) or 7% pequi oil (Pequi group, N = 12) for 6 weeks. The Pequi group presented a more atherogenic lipid profile and more advanced atherosclerotic lesions in the aortic root compared to the Soybean group. However, the Pequi group presented a less advanced lesion in the aorta than the Soybean group and showed lower lipid peroxidation (Soybean group: 50.2 ± 7.1; Pequi group: 30.0 ± 4.8 µmol MDA/mg protein) and anti-oxidized LDL autoantibodies (Soybean group: 35.7 ± 9.4; Pequi group: 15.6 ± 3.7 arbitrary units). Peritoneal macrophages from the Pequi group stimulated with zymosan showed a reduction in the release of reactive oxygen species compared to the Soybean group. Our data suggest that a pequi oil-rich diet slows atherogenesis in the initial stages, possibly due to its antioxidant activity. However, the increase of serum cholesterol induces a more prominent LDL migration toward the intimae of arteries, increasing the advanced atherosclerotic plaque. In conclusion, pequi oil associated with an atherogenic diet worsens the lipid profile and accelerates the formation of advanced atherosclerotic lesions despite its antioxidant action.

Effect of chronic ethanol consumption in female rats subjected to experimental sepsis

The objective of this research was to evaluate the interference of ethanol consumption by female rats with cytokines involved in the sepsis process and its correlation with mortality, the main outcome of sepsis. Female Wistar rats in estrus phase were evaluated in three experiments. Experiment 1 (n=40) was performed to determine survival rates. Experiment 2 (n=69) was designed for biochemical analysis, measurement of cytokine and estrogen levels before and after sepsis, and experiment 3 (n=10) was performed to evaluate bacterial growth by colony counts of peritoneal fluid. In all experiments, treated animals were exposed to a 10% ethanol/water solution (v/v) as the single drinking source, while untreated animals were given tap water. After 4 weeks, sepsis was induced in the rats by ip injection of feces. In experiment 1, mortality in ethanol-exposed animals was delayed compared with those that drank water (48 h; P=0.0001). Experiment 2 showed increased tumor necrosis factor alpha (TNF-α) and decreased interleukin-6 (IL-6) and macrophage migration inhibitory factor in septic animals exposed to ethanol compared to septic animals not exposed. Sepsis also increased TNF-α and IL-6 levels in both ethanol- and water-exposed groups. Biochemical analysis showed higher creatinine, alanine aminotransferase and aspartate aminotransferase and decreased glucose levels in septic animals that were exposed to ethanol. In experiment 3, septic animals exposed to ethanol showed decreased numbers of colony-forming units than septic animals exposed to water. These results suggest that ethanol consumption delays the mortality of female rats in estrus phase after sepsis induction. Female characteristics, most probably sex hormones, may be involved in cytokine expression.

Elevated levels of plasma osteoprotegerin are associated with all-cause mortality risk and atherosclerosis in patients with stages 3 to 5 chronic kidney disease

Osteoprotegerin (OPG) regulates bone mass by inhibiting osteoclast differentiation and activation, and plays a role in vascular calcification. We evaluated the relationship between osteoprotegerin levels and inflammatory markers, atherosclerosis, and mortality in patients with stages 3-5 chronic kidney disease. A total of 145 subjects (median age 61 years, 61% men; 36 patients on hemodialysis, 55 patients on peritoneal dialysis, and 54 patients with stages 3-5 chronic kidney disease) were studied. Clinical characteristics, markers of mineral metabolism (including fibroblast growth factor-23 [FGF-23]) and inflammation (high-sensitivity C-reactive protein [hsCRP] and interleukin-6 [IL-6]), and the intima-media thickness (IMT) in the common carotid arteries were measured at baseline. Cardiac function was assessed by color tissue Doppler echocardiography. After 36 months follow-up, the survival rate by Kaplan-Meier analysis was significantly different according to OPG levels (χ2=14.33; P=0.002). Increased OPG levels were positively associated with IL-6 (r=0.38, P<0.001), FGF-23 (r=0.26, P<0.001) and hsCRP (r=0.0.24, P=0.003). In addition, OPG was positively associated with troponin I (r=0.54, P<0.001) and IMT (r=0.39, P<0.0001). Finally, in Cox analysis, only OPG (HR=1.07, 95%CI=1.02-1.13) and hsCRP (HR=1.02, 95%CI=1.01-1.04) were independently associated with increased risk of death. These results suggested that elevated levels of serum OPG might be associated with atherosclerosis and all-cause mortality in patients with chronic kidney disease.

Dexamethasone and sodium carboxymethyl cellulose prevent postoperative intraperitoneal adhesions in rats

We aimed to evaluate the effects of the barrier agent sodium carboxymethyl cellulose (SCMC) with and without dexamethasone for the prevention of postoperative adhesion formation in a rat model of postoperative peritoneal adhesion. A total of 160 three-month old male and female Wistar rats underwent a laparotomy, and adhesions were induced by ileocecal abrasion. Rats were randomly assigned to 4 groups (n=40 each): group A, untreated; group B, treated with SCMC only; group C1, treated with SCMC + 3 mg dexamethasone, and group C2, treated with SCMC + 8 mg dexamethasone. After 12 days, adhesion formation and histopathological changes were compared. In groups A, B, C1, and C2, the mortality rates were 10, 5, 5, and 5%, respectively. In groups C1 and C2, the adhesions were filmy and easy to dissect and were milder compared with those in groups A and B. The total adhesion score in group C1 (3.38±0.49) was significantly lower than that of group B (6.01±0.57; P<0.01) or group A (8.01±0.67; P<0.05). There was no significant difference in adhesion formation between groups C1 and C2. Compared with groups A and B, groups C1 and C2 exhibited milder histopathological changes. SCMC in combination with dexamethasone can prevent adhesion formation and is a better barrier agent than SCMC alone. The safety and feasibility of SCMC in combination with dexamethasone to prevent adhesion formation after abdominal surgery warrants further clinical study.

Alterações químicas e nutricionais do grão-de-bico (Cicer arietinum L.) cru irradiado e submetido à cocção

O presente trabalho teve por objetivos analisar, em grãos não submetidos à irradiação, a composição centesimal e mineral, para verificar as alterações provocadas pela cocção. Em grãos crus e cozidos, não irradiados (controle) e irradiados (doses de 2, 4, 6, 8 e 10 kGy), foram realizadas também as análises de: disponibilidade de ferro in vitro, digestibilidade da proteína in vitro e perfil de aminoácidos. Os resultados das análises dos minerais demonstraram que ocorreu diminuição significativa (p<0,05) somente para o potássio com o processo de cocção. Na composição centesimal o teor de cinzas e dos carboidratos disponíveis foi significativamente (p<0,05) diminuído. No controle e nas doses de 4 e 6 kGy, a cocção não influenciou na digestibilidade da proteína, mas nos tratamentos que receberam doses de radiação de 2, 8 e 10 kGy, houve diferença significativa (p<0,05), sendo que o grão-de-bico cozido apresentou melhor digestibilidade em doses maiores de radiação, embora os tratamentos tenham apresentado digestibilidade baixa. O grão-de-bico cru apresentou melhor diálise de ferro no controle e nas doses 2 e 4 kGy, e o grão-de-bico cozido apresentou melhora conforme o aumento da dose de radiação. Em relação aos aminoácidos essenciais o grão-de-bico apresentou valor nutricional adequado, exceto para metionina.

Avaliação da disponibilidade de ferro de feijão comum (Phaseolus vulgaris L.) em comparação com carne bovina

O presente trabalho avaliou a disponibilidade do ferro do feijão comum e os efeitos de suas interações com ácido ascórbico e cistina em comparação a disponibilidade deste metal em carne bovina. Para a determinação do teor de ferro e diálise de ferro in vitro, foram realizadas análises químicas nas amostras de carne bovina (C), feijão comum (F), feijão comum com ácido ascórbico (FA), feijão comum com cistina (FCI) e feijão comum com ácido ascórbico e cistina (FACI). Em F foram determinados taninos, ácido fítico e ácido oxálico. Em F foi encontrado 0,065 g de tanino/100 g; 8,03 mg de ácido fítico/g e 7,12 mg de ácido oxálico/g. A quantidade de ferro variou de 9,64 mg/100 g a 10,37 mg/100 g. A amostra FCI e FA apresentaram os menores teores de ferro. A quantidade de ferro encontrada na amostra C foi de 10,37 mg/100 g. A porcentagem de ferro dialisável variou de 17,33% a 24,31%. As amostras de carne bovina apresentaram a maior porcentagem de ferro dialisável, seguida por FACI. A menor porcentagem de ferro dialisável foi observada nas amostras F e FCI. Portanto, pode-se concluir que a adição simultânea de ácido ascórbico e cistina, tornou o ferro presente no feijão mais biodisponível, equiparando-o ao da carne bovina.

Avaliação da disponibilidade de ferro em ovo, cenoura e couve e em suas misturas

A desordem nutricional mais comum no mundo é a deficiência de ferro. Sua disponibilidade é influenciada por outras substâncias. Os objetivos da pesquisa foram: avaliar a disponibilidade de ferro em alimentos fonte deste e de vitamina A, ovo (o), cenoura (c) e couve (cv), e verificar interação do ferro com alfa e beta-caroteno, e com outros interferentes. As misturas foram de ovo com cenoura e ovo com couve nas proporções (1:1), (1:1,5), (1:2), (1:2,5) e (1:3) e 3 alimentos sozinhos, totalizando 13 amostras. As amostras, após preparo, foram submetidas às análises de composição centesimal, ferro total, taninos, ácido fítico, ácido oxálico, alfa-caroteno e b-caroteno e diálise de ferro. Os dados foram analisados por teste de Tukey e correlação. Foi observada correlação positiva do ferro dialisável em relação à umidade e beta-caroteno e negativa para extrato etéreo, proteínas e cinza. A amostra 1,5 c apresentou teores mais elevados de taninos. As amostras 1 cv e 1,5 cv maiores teores de oxalato e ferro dialisável mais baixo. Pode ser concluído que misturas com maiores proporções de cenoura e couve aumentaram a disponibilidade do ferro e não houve interferência dos fatores antinutricionais. O beta-caroteno apresentou correlação positiva com ferro dialisável, exercendo influência na diminuição do efeito dos fatores antinutricionais.

Disponibilidade de ferro em misturas de alimentos com adição de alimentos com alto teor de vitamina C e de cisteína

A disponibilidade do ferro é fator importante na dieta, pois a anemia ferropriva atinge grande parte da população mundial. A cisteína e a vitamina C são fatores que melhoram sua absorção. A pesquisa teve por objetivos avaliar a disponibilidade de ferro em carne, feijão comum (Phaseolus vulgaris) e a combinação de arroz e tomate ao feijão, bem como analisar se o ácido fítico, o ácido oxálico e os taninos das combinações contendo feijão influenciam na disponibilidade de ferro de forma significativa. Os alimentos foram preparados para consumo e as amostras obtidas com a combinação de carne, feijão, arroz e tomate foram: A1 - carne bovina; A2 - feijão comum; A3 - feijão comum e tomate; A4 - feijão comum e arroz; e A5 - feijão comum, arroz e tomate. Foram realizadas as análises de taninos, ácido fítico, ácido oxálico, vitamina C e teor e diálise de ferro in vitro. Os teores de taninos, ácido fítico e ácido oxálico foram baixos para influenciar a disponibilidade do ferro. A diálise de 5,73 a 13,61% indicando que a adição de cisteína e vitamina C em conjunto tem efeito maior do que quando presentes separadamente.

Disponibilidade de ferro in vitro de grãos de soja tostados por diferentes tratamentos

A disponibilidade de alguns minerais, como o ferro, é alterada pela utilização de tratamentos pelo calor. Este trabalho teve por objetivo avaliar a disponibilidade de ferro in vitro e a composição centesimal de grãos de soja tostados por diferentes tratamentos. Realizaram-se cinco tratamentos, sendo dois com secagem prévia e três sem secagem prévia. O controle foi seco em estufa. Os teores de umidade, extrato etéreo, cinzas, fibra alimentar e carboidratos das amostras estudadas diferiram significativamente (p < 0,05), enquanto que os teores de proteína não apresentaram diferenças estatísticas. A quantidade de ferro nas amostras analisadas variou de 83,67 a 58,8 mg.kg-1 e a porcentagem de ferro dialisado foi de 0,95 a 1,38%. Conclui-se que a composição esteve dentro dos valores esperados para grãos de soja e que a tostagem foi responsável pela melhora na diálise de ferro in vitro.

Disponibilidade de cálcio em leite bovino tratado por raios gama

O leite bovino é um alimento de grande importância com fonte de cálcio e proteínas. O objetivo deste trabalho foi o de avaliar os efeitos da radiação gama proveniente do 60Co sobre a disponibilidade de cálcio e o aspecto sensorial. O leite utilizado foi embalado em sacos para leite conforme o encontrado no comércio. As amostras foram submetidas à radiação gama nas doses 0,1, 0,5, 1,0, 2,0 e 3,0 kGy e ficaram armazenadas a 4 °C, e suas avaliações ocorreram nos 1º, 4º, 7º e 10º dias de armazenamento. Foi avaliado o teor de cálcio e a composição centesimal do leite logo após sua obtenção. A diálise de cálcio in vitro foi realizada nos diferentes tempos de armazenamento. Nas duas doses, com pH mais estável na menor dose de radiação e uma dose abaixo, 0,5 e 1,0 kGy, foi realizada análise sensorial. A análise dos dados foi feita empregando teste de Tukey (5%). Quanto à análise físico-química, as amostras irradiadas melhoraram a disponibilidade do cálcio sendo a dose mais adequada a de 1 kGy devido a sua maior estabilidade do pH no período de 10 dias, porém sensorialmente as amostras não foram bem aceitas.

Disponibilidade de ferro, digestibilidade de proteína e teor de β-caroteno em formulados alternativos de baixo custo para alimentação enteral de idosos

O objetivo geral deste trabalho foi elaborar formulados alternativos à base de mistura de alimentos convencionais provenientes da cesta básica distribuída por entidades do município de Piracicaba-SP, entre outros alimentos, com o intuito de suplementar a alimentação enteral de idosos. Os alimentos utilizados para elaboração dos formulados foram fubá, óleo de soja, arroz, feijão, macarrão, sardinha, leite em pó, amido de milho, ovos, proteína texturizada de soja, couve-manteiga e cenoura. Foram realizadas análises químicas: composição centesimal, digestibilidade de proteína, determinação do mineral ferro, diálise de ferro in vitro, determinação de β-caroteno e fatores antinutricionais, assim como fenólicos totais e ácido fítico; e análise de custos dos formulados. Os resultados obtidos foram submetidos às análises estatísticas empregando o teste de Tukey e análises de regressão. Concluiu-se com este estudo que os formulados líquidos apresentaram os melhores resultados nutricionais e viabilidade econômica. Dentre estes, podem-se eleger duas alternativas. O formulado F3 se destacou na disponibilidade de ferro, quantidades de β-caroteno e digestibilidade. O formulado F4 se destacou na distribuição do valor calórico total de macronutrientes. Os formulados contribuem com percentual médio de 20% de adequação para idosos, quando ingeridas duas porções de 250 mL/dia de formulados líquidos ou em pó.