Akt Signaling and Nitric Oxide Synthase as Possible Mediators of the Protective Effect of N-acetyl-L-cysteine in Prediabetes Induced by Sucrose.

The aim of this work was to evaluate possible mechanisms involved in the protective effect of N-acetyl-L-cysteine (NAC) on hepatic endocrine-metabolic, oxidative stress, and inflammatory changes in prediabetic rats. For that, normal male Wistar rats (60 days old) were fed for 21 days with 10% sucrose in their drinking water and 5 days of NAC administration (50 mg/kg, i.p.) and thereafter, we determined: serum glucose, insulin, transaminases, uric acid, and triglyceride levels; hepatic fructokinase and glucokinase activities, glycogen content, lipogenic gene expression; enzymatic and non-enzymatic oxidative stress, insulin signaling pathway, and inflammatory markers. Results showed that alterations evinced in sucrose-fed rats (hypertriglyceridemia, hyperinsulinemia, and high liver fructokinase activity together with increased liver lipogenic gene expression and oxidative stress and inflammatory markers) were prevented by NAC administration. P-endothelial nitric oxide synthase (P-eNOS)/eNOS and pAKT/AKT ratios, decreased by sucrose ingestion, were restored after NAC treatment. In conclusion, the results suggest that NAC administration improves glucose homeostasis, oxidative stress, and inflammation in prediabetic rats probably mediated by modulation of the AKT/NOS pathway. Administration of NAC may be an effective complementary strategy to alleviate or prevent oxidative stress and inflammatory responses observed in type 2 diabetes at early stages of its development (prediabetes).

Protective Effect of Monoterpene Isoespintanol in a Rat Model of Prediabetes Induced by Fructose.

A high-fructose diet (HFD) induces murine alterations like those recorded in human prediabetes. Protective effects of isoespintanol (monoterpene isolated from Oxandra cf. xylopioides) on changes induced by HFD were evaluated. Animals were maintained for 21 days with a standard diet (C), 10% fructose (F), and F plus isoespintanol (FI, 10 mg/kg, i.p.). Glycemia, triglyceridemia, total and HDL-cholesterol, and insulin resistance index (IRX) were determined. Intraperitoneal glucose tolerance test (IGTT) was performed. In the liver, we measured glycogen, lipogenic gene expression (SREBP-1c, GPAT, FAS, and CPT1), oxidative stress (GSH and 3'-nitrotyrosine content), inflammation markers (iNOS, TNF-α, and PAI-1 gene expression; iNOS and COX-2 protein levels), p-eNOS, p-Akt, and p-GSK3ß protein levels. Isoespintanol corrected enhanced triglycerides, lipogenic genes, and IRX, and reduced HDL-cholesterol induced by HFD. Increased liver glycogen and inflammatory markers and decreased GSH, p-Akt, and p-GSK3ß measured in F rats were reversed by isoespintanol, and p-eNOS/e-NOS and iNOS/GADPH ratios were normalized. Isoespintanol restored glucose tolerance (IGTT) compared to F rats. These results demonstrate for the first time that isoespintanol prevents endocrine-metabolic alterations induced by HFD in prediabetic rats. These effects could be mediated by Akt/eNOS and Akt/GSK3ß pathways, suggesting its possible use as a therapeutic tool for the prevention of diabetes at early stages of its development (prediabetes).

A study of the effects of imidacloprid under laboratory and field conditions on nymphs of Triatoma infestans (Hemiptera: Reduviidae)

The aim of this study was to determine imidacloprid's lethal activity against fifth-instar nymphs of Triatoma infestans. In the first stage of this work, it was assayed the topical application of this insecticide on non-fed and repletion-fed nymphs. Results showed a DL50 three times greater in non-fed bugs than in those fully engorged. The presence of food determined less time for the insecticide's maximum lethal effect: 24 h post topical application in fed nymphs and 72 h in non-fed nymphs. In the study's second stage, we assayed a xenointoxication assay on dogs. The commercial products, Advantage®, Bayer (imidacloprid 10 % p/v) and Power Ultra®, Brouwer (imidacloprid 5.15 %, permethrin 40 % and piperonyl butoxide [PBO] 3%) were evaluated. Following administration of the insecticide, nymphs were fed on dogs 24, 72, 168, 240 and 336 h. Blood intake was similar in nymphs exposed to treated dogs versus controls. Although both commercial products showed low triatomicidal activity, a higher efficacy of the product combining imidacloprid with the synergist piperonyl butoxide and permethrin versus the product with imidacloprid as the only active ingredient was observed, causing in nymphs a mortality rate of 36.3 % and 20.7 %, respectively. Our results suggest that imidacloprid, alone or in combination with permethrin and PBO, is not an alternative for control of T. infestans.

Productos naturales para el tratamiento de la diabetes (I): mecanismos de acción / Produtos naturais para o tratamento da diabetes (I): mecanismos de acçao / Natural products for the treatment of diabetes (I): mechanism of action

La diabetes mellitus tipo 2 (DMT2) es una enfermedad metabólica caracterizada por un hipergluciemia persistente, la cual, si no es tratada adecuadamente, a largo plazo puede producir complicaciones cardiovasculares, trastornos renales o retinopatía. El desarrollo de la enfermedad puede prevenirse o retrasarse en personas con tolerancia a la glucosa alterada, mediante la implementación de los cambios de estilo de vida o el uso de agentes terapéuticos. Algunos de estos medicamentos se han obtenido a partir de plantas o tienen origen microbiano, como la galegina aislada de Galega officinalis, que tiene una gran similitud estructural con la metformina. Picnogenol, miglitol, acarbosa y voglibosa son otros antidiabéticos de origen natural. En la presente revisión se recopilan los principales artículos sobre plantas medicinales y productos naturales utilizados para el tratamiento de la DMT2 y sus comorbilidades, sobre la base de sus mecanismos de acción como agentes antidiabéticos. S excluyen las drogas vegetales ricas en polisacáridos. La inhibición de la alpha-glucosidasa y la alpha-amilasa, efectos sobre la capacitación y transportadores de glucosa, y la modificación de mecanismos mediados por el receptor activados por proliferadores de peroxisomas (PPAR), la inhibición de la actividad tirosina-fosfatasa 1B (PTP1B), la modificación de la expresión génica y las actividades de hormonas implicadas en la homeostasis de la glucosa, tales como la adiponectina, resistina e incretina, yl a reducción del estrés oxidativo, son algunos de los mecanismos en los que productos naturales están involucrados (AU)

Adiabetes mellitus tipo 2 (DMT2) è uma doença metabólica caracterizada por hiperglicemia persistente, a qual, se nao for adequadamente tratada, a longo prazo pode originar complicaçoes cardiovasculares, disturbios renais ou retinopatía. O desnvolvimiento da doença pode ser prevenido ou adiado empessoas com tolerancia à glicose alterada, através da implementaçao de mudanças no estilo de vido ou do uso de agentes terapéuticos. Alguns destes medicamentos tem origen microbiana ou sao derivados de plantas, tal como a galefina, composto isolado da espècie Galega officinalis, que tem uma grande semelhança estrutural com a metformina. Picnogenol, acarbose, miglitol e Voglibose sao exemplos de outros antiabéticos de origen natural. Esta revisao compila os principais artigos sobre plantas medicinais e productos naturais usados para o tratamento da DMT2 e suas comorbilidades, tendo como base os respectivos mecanismos de acçao como agentes antidiabéticos. As drogas vegetais ricas em policárideos sao excluidas. A inhibiçao de alpha-glicosade e da alpha-amilase, efeitos sobre a captaçao e transportadores de glicose, modificaçao de mecanismos mediados pelos recptores activados por proliferadores de peroxisomas (PPAR), inhibiçao da actividade da tirosina fosfatase 1B (PTB1B), modificaçao da expressao génica e da actividade de hormonas envolvidas na homeostase da glicose, como adiponectina, resistina e incretinas, bem como a reduçao do stress oxidativo, sao alguns dos mecanismos em que os productos naturais estao envueltos (AU)

Type 2 diabetes mellitus is a metabolic disorder characterized by persistent hyperglycemia, which can cause long-term cardiovascular complications, kidney disorders, retinopathy and circulatory problems. Development of disease can be prevented or delayed in people with impaired glucose tolerance, by implementing changes in lifestyle or with the use of therapeutic agents. Some of these medicines are derived from plants or microbial origin, such as galegine isolated from Galega officinalis, which has a great similarity with the antidiabetic drug metformin. Pycnogenol, acarbose, miglitol and voglibose are other antidiabetic agents from natural origin. This review compiles the main articles on medicinal plants and natural products used for the treatment of diabetes and its comorbidities, focusing on their mechanisms of action as antidiabetic agents. Polysacharide containing hebal drugs are excluded. The inhibition of alpha-glucosidase and alpha-amylase, the effect on glucose uptake and glucose transporters, the modification of perosixome proliferator activated receptors (PPAR), inhibition of protein-tyrosine phosphatase activity 1B (PTP1B), modification of gene expression and activities of hormones involved in glucose homeostasis, such as adiponectin, resistin and incretin, as well as the reduction of oxidative stress are some of the mechanisms in which natural products are involved (AU)

Drogas vegetales para el tratamiento de la diabetes (II): ensayos clínicos / Drogas vegetais para o tratamento da diabetes (2): ensaios clínicos / Herbal drugs for the treatment of diabetes (2): clinical trials

En un artículo previo se analizaron los mecanismos de acción de los principales compuestos antidiabéticos de plantas medicinales utilizadas en medicina tradicional y en fitoterapia. La presente revisión se ha enfocado como una continuación de la anterior, para lo cual se han seleccionado los ensayos clínicos más relevantes realizados con las principales especies antidiabéticas estudiadas hasta la fecha. Ajo, alcaparra, alholva, aloe, banaba, cacao, café, canela de China, cúrcuma, gimnema, guayaba, mate, melón amargo, nogal, olivo, ortiga mayor, salvia, soja y té verde son las plantas medicinales conocidas que han sido objeto de estudios en humanos. Aunque el número de ensayos es limitado y las características de los mismos dispares, aún así muchas de ellas han demostrado un excelente perfil yse pueden considerar de interés para estudios más definidos y completos (AU)

No artigo anterior foram analisados os mecanismos de açáo dos principais compostos antidiabéticos de plantas medicinais utilizadas na medicina tradicional e da medicina herbal. Esta avaliaçáo tem sido focada como uma continuaçáo do anterior, para o qual nos selecionamos os ensaios clinicos mais relevantes com os principais espécies antidiabéticos estudados até o momento. Alho, alcaparra, feno-grego, aloe, banaba, cacau, café, chinés canela, açafráo, gymnema, goiaba, magante, meláo amargo, noz, azeitona, urtiga, sálvia, soja e chá verde 550 conhecidos plantas medicinais que tem sido objecto de estudos em seres humanos. Embora o número de testes é limitado e as caracteristicas desses dispares, mas muitos deles tem demonstrado um excelente perfil e pode ser considerado de interesse para estudos mais definidos e abrangentes (AU)

In the previous review, we analyzed the mechanisms of action of the main antidiabetic compounds from medicinal plants used in traditional herbal medicine and phytotherapy. This review has been focused as a continuation of the previous one, in which we have selected the most relevant clinical trials with the major antidiabetic species. Aloe, banaba, bitter melon, caper, Chinese cinnamon, cocoa, coffee, fenugreek, garlic, green tea, guava, gymnema, mate, nettle, olive, saga, soy, stinging, turmeric and walnut, are known medicinal plants that have been subject of studies in humans. Although the number of tests is limited and the characteristics of these unlike, yet many of them have shown an excellent profile and can be considered of interest to more defined and comprehensive studies (AU)

Epidemiologia del latrodectismo en la Provincia de Buenos Aires, Argentina / Epidemiology of latrodectism in province of Buenos Aires, Argentina

Säo relatados os resultados do latrodecismo e seu tratamento específico durante um período de 10 anos (1979-1988), em Buenos Aires, Argentina. Säo evidenciados dados de distribuiçäo de acidentes por ano, meses, por sexo, residência do acidentado, regiäo corporal da picada, sintomas apresentados, tempo transcorrido entre o acidente e a aplicaçäo do soro antilatrodectus e a captura do animal agressor. Observou-se o pico entre 1982 a 1983 com 83 acidentes e uma média de 28,1 acidentes anuais, com maior índice de dezembro a março. Com respeito ao sexo e local de residência do acidentado, 80 por cento corresponde a homens, sendo principalmente trabalhadores rurais os mais afectados. A maior percentagem dos acidentes localizou-se no antebraço, cintura pélvica e coxa. Com respeito ao tempo transcorrido desde o acidente até a aplicaçäo do soro, 46 por cento foi realizado entre as três primeiras horas, sendo que foram capturados apenas 15 por cento dos animais agressores

Ultrastructural study of the endocrine pancreas of the toad Bufo arenarum

The aim of the present report was to identify by electron microscopy the different endocrine cell types of the toad pancreas. Thus, we studied the pancreas from male specimens of Bufo arenarum with routine techniques for transmission electron microscopy. The results showed the presence of four endocrine cells types which would correspond to those responsible for the different pancreatic hormonal secretions in other species (B, A, D and PP cells). Type 1 cells contained rounded secretory granules with a clear halo which responded to two varieties: a) measuring 200 to 400 mm, and b) having a crystalloid core and a diameter of 400 to 600 nm; these cells would correspond to B cells showed rounded or irregular granules of 104 to 400 nm; they would be equivalent to A cells. Type 3 cells presented polymorphic ganules, most of them peanut-shaped, measuring 115 to 850 nm; they would resemble D cells. Finally, Type 4 cells contained rounded granules of 80 to 400 nm; these cells would correspond to PP cells. In addition, we also observed mixed cells exhibiting similar characteristics to acinar cells, but containing secretory granules resembling those found in some of the endocrine cell types; these would correspond to the acinar-islet cells reported in other animals. In conclusion, we described the ultrastructure of the toad endocrine pancreas and compare it with previous observations made in other amphibians.