Efecto del estrés crónico y de la masticación sobre los niveles séricos de interleuquina-6 e interferón-gama / Effect of chronic stress and chewing on serum interleukin-6 and interferon-gamma levels

Introducción: el estrés crónico afecta el equilibrio inmunológico alterando los niveles séricos de interleuquina-6 (IL-6) e interferón gama (INF-γ), dicha alteración afecta al sistema nervioso y al comportamiento humano. La masticación adecuada disminuiría dichos efectos. El objetivo del estudio fue determinar el efecto del estrés crónico y de la masticación sobre los niveles séricos de IL-6 e INF-γ. Métodos: experimento donde se emplearon 64 ratones Balb/c de 8 semanas de edad. Se dividieron en 4 tratamientos: Grupo NE: Masticación normal + estrés, Grupo N: masticación normal sin estrés, Grupo DE: Masticación deficiente + estrés, Grupo D: masticación deficiente sin estrés. Mediante test de ELISA se midió IL-6 e IFN-γ alfinal de la 4ta y de la 8va semana de tratamiento. Resultados: tanto la IL-6 como el IFN-γ fueron mayores en el grupo DE (p<0,05) al final de la 4ta semana. Al evaluarlos al término de la 8va semana se observó que en el grupo NE se incrementó la IL-6 respecto al resto de grupos (p<0,0001), y en el grupo DE fue donde se encontró mayor cantidad de IFN-γ (p<0,0001). Conclusión: el estrés crónico y la masticación deficiente incrementan los niveles séricos de IL-6 e IFN-γ. En cambio, la adecuada masticación disminuye el nivel de tales citoquinas al final de la cuarta semana de tratamiento.

Introduction: chronic stress affects the immune balance by altering the serum levels of interleukin-6 (IL-6) and gamma interferon (INF-γ), this alteration affects the nervous system and human behavior. Appropriate chewing would lessen these effects. The aim of this study was to determine the effect of chewing and chronic stress over serum levels of IL-6 and INF-γ. Methods: experiment in which 64 Balb/C mice of 8 weeks of age were used, they were divided into 4 treatments: Group NE: Normal chewing + stress, Group N: normal chewing without stress, Group DE: Chewing poor + stress, Group D: poor chewing without stress. IL-6 and IFN-γ were measured by ELISA after 4 and 8 weeks of treatment. Results: both IL-6 and IFN-γ were higher in the DE group (p < 0,05) at the end of fourth week of treatment. When evaluating the animals at the end of the eighth week of treatment, it was observed that in the NE group, the IL-6 was increased with respect to the rest (p < 0,0001) and the DE group showed more IFN-γ (p < 0,0001). Conclusion: stress and poor chewing increase serum IL-6 and IFN-γ. In contrast, appropriate chewing decreases the effects of stress on the increase of such cytokines at the end of the fourth week of treatment in animals.

Neuropsychological Test Performance in Cognitively Normal Spanish-speaking Nonagenarians with Little Education.

To find associations of age, sex, and education with neuropsychological test performance in cognitively normal Spanish-speaking Costa Rican nonagenarians with little education; to provide norms; and to compare their performance with similar Puerto Ricans. For 95 Costa Ricans (90-102 years old, 0-6 years of education), multiple regression assessed associations with demographics of performance on six neuropsychological tests. Analyses of covariance compared them with 23 Puerto Ricans (90-99 years old). Younger age and being female-but not education-were associated with better performance on some neuropsychological tests, in particular episodic memory. The Puerto Ricans performed better on learning and memory tasks. In cognitively intact Spanish-speaking nonagenarians with little or no education, education did not affect test performance. Additional studies of the effect of education on cognitive performance are warranted in other samples with extremely low education or old age. National differences in performance highlight the importance of group-specific norms.

Association of apolipoprotein E-e4 and dementia declines with age.

OBJECTIVE: To study the association of dementia with apolipoprotein E-e4 (APOE-e4) and its interaction with age in a nonagenarian Costa Rican group (N-sample) and a general elderly contrast group (GE-sample). METHODS: In both case-control studies, participants were cognitively intact or diagnosed with dementia. The N-sample (N = 112) was at least age 90 years; the GE-sample (N = 98) was at least age 65 years. RESULTS: Dementia and APOE-e4 were not significantly associated in the N-sample, but were in the GE-sample. There was a significant interaction of age with APOE-e4 in the N-sample, but not in the GE-sample. Descriptively dividing the N-sample at the median (age 93 years) showed a group interaction: APOE-e4 was more associated with dementia in the younger N-sample than in the older N-sample, where six of seven APOE-e4 carriers were cognitively intact. CONCLUSIONS: The results support the reduction in association of APOE-e4 with dementia in extreme old age, consistent with a survivor effect model for successful cognitive aging.

Heritability of cognitive functions in families of successful cognitive aging probands from the Central Valley of Costa Rica.

We sought to identify cognitive phenotypes for family/genetic studies of successful cognitive aging (SCA; maintaining intact cognitive functioning while living to late old age). We administered a battery of neuropsychological tests to nondemented nonagenarians (n = 65; mean age = 93.4 ± 3.0) and their offspring (n = 188; mean age = 66.4 ± 5.0) from the Central Valley of Costa Rica. After covarying for age, gender, and years of education, as necessary, heritability was calculated for cognitive functions at three pre-defined levels of complexity: specific neuropsychological functions (e.g., delayed recall, sequencing), three higher level cognitive domains (memory, executive functions, attention), and an overall neuropsychological summary. The highest heritability was for delayed recall (h² = 0.74, se = 0.14, p < 0.0001) but significant heritabilities involving memory were also observed for immediate recall (h² = 0.50), memory as a cognitive domain (h² = 0.53), and the overall neuropsychological summary (h² = 0.42). Heritabilities for sequencing (h² = 0.42), fluency (h² = 0.39), abstraction (h² = 0.36), and the executive functions cognitive domain (h² = 0.35) were also significant. In contrast, the attention domain and memory recognition were not significantly heritable in these families. Among the heritable specific cognitive functions, a strong pleiotropic effect (i.e., evidence that these may be influenced by the same gene or set of genes) for delayed and immediate recall was identified (bivariate statistic = 0.934, p < 0.0001) and more modest but significant effects were found for four additional bivariate relationships. The results support the heritability of good cognitive function in old age and the utilization of several levels of phenotypes, and they suggest that several measures involving memory may be especially useful for family/genetic studies of SCA.

Curcumin could prevent methemoglobinemia induced by dapsone in rats.

The curcumin's effect given orally by gavage in single- or multiple-dose regimens on methemoglobinemia induced by dapsone (DDS) was investigated in male Wistar rats. In the single-dose regimen, groups of 10 rats received either vehicle alone, or curcumin at 0.1, 1.0, 10, or 30 mg/kg body weight (bw), or curcumin at 0.02, 0.1, 1, 10, or 30 mg/kg bw plus DDS at 40 mg/kg bw, intraperitoneally (i.p.), 2 hours after. In the multiple-dose regimen, groups of 10 rats received either vehicle alone, or curcumin at 0.1, 1.0, 10, or 30 mg/kg bw for 5 days, with or without DDS (40 mg/kg bw, i.p.) 2 hours after on the fifth day. In both regimens, further groups of 10 rats were given DDS alone (positive controls) or normal saline (negative controls) i.p. Single-dose treatment with curcumin at 0.02 and 0.1 mg/kg bw significantly reduced DDS-induced methemoglobin formation, while the higher doses showed a pro-oxidant effect, significantly increasing DDS-induced methemoglobinemia. In the multiple-dose regimen, treatment with curcumin at 0.1 mg/kg bw significantly reduced DDS-induced methemoglobin formation, but the higher doses were without significant effect compared to DDS alone. It is concluded that curcumin at low doses mitigates methemoglobinemia induced by dapsone in rats, both in single- and multiple-dose regimens.

Quercetin reduces inflammatory pain: inhibition of oxidative stress and cytokine production.

Quercetin (1) is known to have both antioxidant and antinociceptive effects. However, the mechanism involved in its antinociceptive effect is not fully elucidated. Cytokines and reactive oxygen species have been implicated in the cascade of events resulting in inflammatory pain. Therefore, we evaluated the antinociceptive mechanism of 1 focusing on the role of cytokines and oxidative stress. Intraperitoneal and oral treatments with 1 dose-dependently inhibited inflammatory nociception induced by acetic acid and phenyl-p-benzoquinone and also the second phase of formalin- and carrageenin-induced mechanical hypernociception. Compound 1 also inhibited the hypernociception induced by cytokines (e.g., TNFalpha and CXCL1), but not by inflammatory mediators that directly sensitize the nociceptor such as PGE2 and dopamine. On the other hand, 1 reduced carrageenin-induced IL-1beta production as well as carrageenin-induced decrease of reduced glutathione (GSH) levels. These results suggest that 1 exerts its analgesic effect by inhibiting pro-nociceptive cytokine production and the oxidative imbalance mediation of inflammatory pain.

Caracterización social y comercial de los sistemas ovinos y caprinos de la región noroeste de República Dominicana / Social and commercial profile of the sheep and goat cattle systems in the northwestern region of the Dominican Republic / Caracterização social e comercial dos sistemas ovinos e caprinos da região noroeste da República Dominicana

A fin de estudiar los aspectos sociales y comerciales que caracterizan al sistema de producción de ovinos y caprinos de la región noroeste de República Dominicana, se muestrearon 94 explotaciones (24% de la población), aplicando el método de encuesta directa mediante muestreo aleatorio estratificado con asignación proporcional. Las explotaciones que conforman este sistema ganadero son en un 82% familiares, con antigüedad en torno a 16 ±1,3 años. El 93% de los propietarios son hombres, con edad media de 51 ±1,2 años, el 63% ha iniciado estudios primarios y 8% no ha realizado estudios. El régimen de tenencia de tierra está relacionado al tipo de explotación según la especie productiva (p<0,05); el 84% de las explotaciones caprinas se desarrollan en tierras públicas y las explotaciones ovinas y mixtas hacen mayor uso de terrenos privados. Para 53% de los propietarios la producción de ovinos y caprinos constituye la actividad principal y 78% de las explotaciones utiliza mano de obra familiar. La comercialización se efectúa mediante canales largos con los carniceros (70%), mientras el 14% de las explotaciones vende directamente al consumidor. El sistema estudiado se caracteriza por explotaciones familiares, cuyos propietarios presentan edad avanzada, bajo nivel de formación, alta dependencia de terrenos públicos y escasa participación activa del productor en la comercialización. Esta situación limita el acceso al crédito y la adopción e innovación tecnológica. Finalmente, se considera que el fomento del asociacionismo podría ayudar a superar estas restricciones.

In order to study the social and commercial aspects that characterize the sheep and goat cattle production systems in the Northwestern region of the Dominican Republic, 94 farms (24% of the population) were sampled, applying the direct survey method through random sampling with proportional weighting. The farms comprising this cattle system are 82% family owned, with a standing of 16 ±1.3 years. Of the owners, 93% are men, with average age of 51 ±1.2 years; 63% began primary schooling and 8% did not go to school. The land ownership regime is related to the type of exploitation according to the productive species (p<0.05); 84% of goat farms are on public land, and sheep and mixed farms make a larger use of private lots. For 53% of the owners the production of sheep and goats is their main activity and 75% of the farms use family labor. Marketing is carried out through long channels to butchers (70%), while 14% of the farms sell directly to consumers. The system under study is characterized by family farms whose owners are of advanced age, low training level, with a high dependency on public land y meager participation of the producer in marketing. This situation limits access to credit, as well as technological adoption and innovation. Finally, it is considered that the promotion of associations could help overcome such restrictions.

Com a finalidade de estudar os aspectos sociais e comerciais que caracterizam o sistema de produção de ovinos e caprinos da região noroeste da República Dominicana, foi realizada amostragem em 94 explorações (24% da população), aplicando o método de pesquisa direta mediante amostra aleatória estratificada com designação proporcional. As explorações que conformam este sistema de criação de gado são 82% familiares, com antiguidade aproximada de 16 ±1,3 años. 93% dos proprietários são homens, com idade média de 51 ±1,2 anos, 63% tem iniciado estudos primários e 8% não tem realizado estudos. O regime de posse de terra esta relacionado ao tipo de exploração segundo a espécie produtiva (p<0,05); 84% das explorações caprinas se desenvolvem em terras públicas e as explorações ovinas e mistas utilizam em maior proporção, terrenos privados. Para 53% dos proprietários a produção de ovinos e caprinos constitui a atividade principal e 78% das explorações utiliza mão de obra familiar. A comercialização é efetuada mediante longos canais, 70% com os açogueiros, enquanto que 14% das explorações vende diretamente ao consumidor. O sistema estudado se caracteriza por explorações familiares, cujos proprietários apresentam idade avançada, baixo nível de formação, alta dependência de terras públicas e escassa participação ativa do produtor na comercialização. Esta situação limita o acesso ao crédito e a adoção e inovação tecnológica. Finalmente, se considera que o fomento do associacionismo poderia ajudar a superar estas restrições.

Quantification of carbamazepine, carbamazepine-10,11-epoxide, phenytoin and phenobarbital in plasma samples by stir bar-sorptive extraction and liquid chromatography.

A sensitive and reproducible stir bar-sorptive extraction and high-performance liquid chromatography-UV detection (SBSE/HPLC-UV) method for therapeutic drug monitoring of carbamazepine, carbamazepine-10,11-epoxide, phenytoin and phenobarbital in plasma samples is described and compared with a liquid:liquid extraction (LLE/HPLC-UV) method. Important factors in the optimization of SBSE efficiency such as pH, extraction time and desorption conditions (solvents, mode magnetic stir, mode ultrasonic stir, time and number of steps) assured recoveries ranging from 72 to 86%, except for phenytoin (62%). Separation was obtained using a reverse phase C18 column with UV detection (210nm). The mobile phase consisted of water:acetonitrile (78:22, v/v). The SBSE/HPLC-UV method was linear over a working range of 0.08-40.0microgmL(-1) for carbamazepine, carbamazepine-10,11-epoxide and phenobarbital and 0.125-40.0microgmL(-1) for phenytoin, The intra-assay and inter-assay precision and accuracy were studied at three concentrations (1.0, 4.0 and 20.0microgmL(-1)). The intra-assay coefficients of variation (CVs) for all compounds were less than 8.8% and all inter-CVs were less than 10%. Limits of quantification were 0.08microgmL(-1) for carbamazepine, carbamazepine-10,11-epoxide and phenobarbital and 0.125microgmL(-1) for phenytoin. No interference of the drugs normally associated with antiepileptic drugs was observed. Based on figures of merit results, the SBSE/HPLC-UV proved adequate for antiepileptic drugs analyses from therapeutic levels. This method was successfully applied to the analysis of real samples and was as effective as the LLE/HPLC-UV method.

Role of cytokines in mediating mechanical hypernociception in a model of delayed-type hypersensitivity in mice.

In the present study, we used the electronic version of the von Frey test to investigate the role of cytokines (TNF-alpha and IL-1beta) and chemokines (KC/CXCL-1) in the genesis of mechanical hypernociception during antigen-induced inflammation in mice. The nociceptive test consisted of evoking a hindpaw flexion reflex with a hand-held force transducer (electronic anesthesiometer) adapted with a 0.5 mm(2) polypropylene tip. The intraplantar administration of methylated bovine serum albumin (mBSA) in previously immunized (IM), but not in sham-immunized (SI) mice, induced mechanical hypernociception in a dose-dependent manner. Hypernociception induced by antigen was reduced in animals pretreated with IL-1ra and reparixin (a non-competitive allosteric inhibitor of CXCR2), and in TNF receptor type 1 deficient (TNFR1-/-) mice. Consistently, antigen challenge induced a time-dependent release of TNF-alpha, IL-1beta and KC/CXCL-1 in IM, but not in SI, mice. The increase in TNF-alpha levels preceded the increase in IL-1beta and KC/CXCL1. Antigen-induced release of IL-1beta and KC/CXCL1 was reduced in TNFR1-/- mice, and TNF-alpha-induced hypernociception was inhibited by IL-1ra and reparixin. Hypernociception induced by IL-1beta in immunized mice was inhibited by indomethacin, whereas KC/CXCL1-induced hypernociception was inhibited by indomethacin and guanethidine. Antigen-induced hypernociception was reduced by indomethacin and guanethidine and abolished by the two drugs combined. Together, these results suggest that inflammation associated with an adaptive immune response induces hypernociception that is mediated by an initial release of TNF-alpha, which triggers the subsequent release of IL-1beta and KC/CXCL1. The latter cytokines in turn stimulate the release of the direct-acting final mediators, prostanoids and sympathetic amines.

IL-33 mediates antigen-induced cutaneous and articular hypernociception in mice.

IL-33, a new member of the IL-1 family, signals through its receptor ST2 and induces T helper 2 (Th2) cytokine synthesis and mediates inflammatory response. We have investigated the role of IL-33 in antigen-induced hypernociception. Recombinant IL-33 induced cutaneous and articular mechanical hypernociception in a time- and dose-dependent manner. The hypernociception was inhibited by soluble (s) ST2 (a decoy receptor of IL-33), IL-1 receptor antagonist (IL-1ra), bosentan [a dual endothelin (ET)(A)/ET(B) receptor antagonist], clazosentan (an ET(A) receptor antagonist), or indomethacin (a cyclooxygenase inhibitor). IL-33 induced hypernociception in IL-18(-/-) mice but not in TNFR1(-/-) or IFNgamma(-/-) mice. The IL-33-induced hypernociception was not affected by blocking IL-15 or sympathetic amines (guanethidine). Furthermore, methylated BSA (mBSA)-induced cutaneous and articular mechanical hypernociception depended on TNFR1 and IFNgamma and was blocked by sST2, IL-1ra, bosentan, clazosentan, and indomethacin. mBSA also induced significant IL-33 and ST2 mRNA expression. Importantly, we showed that mBSA induced hypernociception via the IL-33 --> TNFalpha --> IL-1beta --> IFNgamma --> ET-1 --> PGE(2) signaling cascade. These results therefore demonstrate that IL-33 is a key mediator of immune inflammatory hypernociception normally associated with a Th1 type of response, revealing a hitherto unrecognized function of IL-33 in a key immune pharmacological pathway that may be amenable to therapeutic intervention.

Exposição ambiental a desreguladores endócrinos: alterações na homeostase dos hormônios esteroidais e tireoideanos / Environmental exposure to endocrine disrupters: alterations in steroidal and thyroid hormones homeostasis

Endocrine disruptors, exogenous compounds that alter the endogenous hormone homeostasis, have been systematically discharged in the environment during the last 60 years. These contaminants have been related to the decrease of human sperm number and increased of the incidence of testicular, breast and thyroid cancer. During the same period, developmental and reproductive effects have also been documented in wildlife species. This work presents a review of the effects and mechanisms of action of steroidal and thyroid disruptors. Several studies from 1950 until 2008 were reviewed in PubMed, ScienceDirect databases and text books. Our findings showed that endocrine disruptors can act by the following mechanisms: i) inhibition of enzymes related to hormone synthesis; ii) alteration of free concentration of hormones by interaction with plasmatic globulins; iii) alteration in expression of hormone metabolism enzymes; iv) interaction with hormone receptors, acting as agonists or antagonists; v) alteration of signal transduction resulting from hormone action. The importance of the identification of endocrine disruptors involves characterization of environmental contaminants and inquiry of new substances discharged in the environment. The minimization of exposure and/or rationalization of the use of these compounds are related to the preservation of some species, in order to prevent extinction process.

Desreguladores endócrinos, substâncias exógenas que alteram a homeostase de hormônios endógenos, têm sido constantemente lançados no ambiente durante os últimos 60 anos. Esses contaminantes têm sido relacionados à diminuição da contagem espermática humana e ao aumento da incidência de câncer de testículo, mama e tireóide. No mesmo período, alterações no desenvolvimento e reprodução foram documentadas em espécies de animais selvagens. O objetivo do trabalho foi revisar os efeitos e mecanismos de ação dos desreguladores endócrinos que alteram a homeostase dos hormônios esteroidais e tireoideanos. Foi realizado um levantamento de artigos do período de 1950 a 2008 através das bases de dados PUBMED e ScienceDirect, além de livros da área. Os resultados mostram que os desreguladores endócrinos podem agir pelos seguintes mecanismos: i) inibição de enzimas relacionadas com a síntese de hormônios; ii) alteração da concentração livre de hormônios através da interação com globulinas plasmáticas; iii) alteração da expressão de enzimas relacionadas ao metabolismo hormonal; iv) interação com receptores hormonais, agindo como agonistas ou antagonistas; v) alteração da transdução de sinais resultante da ação hormonal. A importância da identificação dos desreguladores endócrinos envolve o estudo dos contaminantes ambientais e a investigação de novas substâncias lançadas no meio ambiente. A minimização da exposição e/ou a racionalização do uso desses compostos está relacionada a preservação de espécies, para previnir processos de extinção.

Anti-inflammatory and analgesic effects of the sesquiterpene lactone budlein A in mice: inhibition of cytokine production-dependent mechanism.

The anti-inflammatory activities of some medicinal plants are attributed to their contents of sesquiterpene lactones. In the present study, the anti-inflammatory and anti-nociceptive activity of a sesquiterpene lactone isolated from Viguiera robusta, budlein A in mice was investigated. The treatment with budlein A dose--(1.0-10.0 mg/kg, p.o., respectively) dependently inhibited the carrageenan-induced: i. neutrophil migration to the peritoneal cavity (2-52%), ii. neutrophil migration to the paw skin tissue (32-74%), iii. paw oedema (13-74%) and iv. mechanical hypernociception (2-58%) as well as the acetic acid-induced writhings (0-66%). Additionally, budlein A (10.0 mg/kg) treatment inhibited the mechanical hypernociception-induced by tumour necrosis factor (TNF-alpha, 36%), Keratinocyte-derived chemokine (KC, 37%) and Interleukin-1beta (IL-1beta, 28%), but not of prostaglandin E(2) or dopamine. Budlein A also inhibited the carrageenan-induced release of TNF-alpha (52%), KC (70%) and IL-1beta (59%). Furthermore, an 8 days treatment with budlein A inhibited Complete Freund's adjuvant (10 microl/paw)-induced hypernociception, paw oedema and paw skin myeloperoxidase activity increase while not affecting the motor performance or myeloperoxidase activity in the stomach. Concluding, the present data suggest that budlein A presents anti-inflammatory and antinociceptive property in mice by a mechanism dependent on inhibition of cytokines production. It supports the potential beneficial effect of orally administered budlein A in inflammatory diseases involving cytokine-mediated nociception, oedema and neutrophil migration.