RESUMO O uso de soluções eletrolíticas hipotônicas na hidratação enteral ainda é pouco estudado em bezerros. O objetivo do presente estudo foi avaliar os efeitos de soluções eletrolíticas enterais de manutenção com diferentes concentrações de acetato de sódio e diferentes osmolaridades em bezerros. Para isso, foram utilizados 18 bezerros, seis machos e 12 fêmeas, holandeses, com 20 dias de nascidos e pesando por volta dos 52kg. Os animais foram divididos aleatoriamente em três grupos e cada grupo recebeu um dos tratamentos. As três soluções eletrolíticas continham os mesmos componentes, mas em diferentes concentrações, resultando em uma solução hiposmótica, uma isosmótica e uma hiperosmótica. Cada animal foi mantido em hidratação enteral durante 12 horas com taxa de infusão de 15mL kg-1h-1. Foram aferidos perímetro abdominal, peso corporal, consistência das fezes, glicose e lactato plasmático, pH, pCO2, HCO- 3 e excesso de base nos seguintes tempos: T0h, T6h, T12h e T24h. A solução hiposmótica não gerou aparecimento de diarreia, enquanto a isosmótica e a hiperosmótica geraram. Independentemente da dose utilizada, o acetato não causou alcalose metabólica nos animais avaliados. Os resultados sugerem que o uso da solução hiposmótica em bezerros diarreicos, desidratados e sem acidose metabólica, pode ser clinicamente importante.

ABSTRACT The use of hypotonic electrolytic solutions in enteral fluid therapy is still understudied in calves. The objective of the present study was to evaluate the effects of maintenance enteral electrolytic solutions with different concentrations of sodium acetate and different osmolarities in calves. For this, 18 Holstein calves, six male and 12 female, 20 days old and weighing around 52kg, were used. The animals were randomly divided into three groups and each group received one of the treatments. The three electrolytic solutions contained the same components in different concentrations, resulting in a hyposmotic, an isosmotic and a hyperosmotic solution. Each animal was maintained in enteral fluid therapy for 12 hours with infusion rate of 15mL kg-1 h-1. Abdominal circumference, body weight, feces consistency, glucose and plasma lactate, pH, pCO2, HCO- 3 and BE were measured at the following times: T0h, T6h, T12h and T24h. The hyposmotic solution did not generate the onset of diarrhea, while the isosmotic and the hyperosmotic did. Regardless of the dose used, acetate did not cause metabolic alkalosis in the evaluated animals. The results suggest that the use of hyposmotic solution in diarrheic calves, dehydrated and without metabolic acidosis, may be clinically important.

RESUMO: A identificação de compostos com potencial alelopático produzidos pelas plantas de cobertura pode auxiliar na seleção de espécies para fins de manejo de plantas daninhas em sistema de plantio direto. O objetivo deste estudo foi identificar os principais compostos fenólicos com potencial alelopático na parte aérea das plantas de cobertura centeio (Secale cereale L.) e nabo forrageiro (Raphanus sativus L.), bem como avaliar se o sistema de cultivo e o estádio fenológico influenciam na produção desses metabólitos secundários e na emergência de plantas daninhas. Foram coletadas amostras da parte aérea das plantas de cobertura aos 60, 80 e 100 dias após a semeadura (DAS) e 15 e 30 dias após o acamamento delas (DAA), em um experimento de campo. Foi avaliada a emergência de plantas daninhas aos 45, 75 e 100 DAA das plantas de cobertura. No centeio, os compostos majoritários foram o 6-metoxi-2-benzoxazolinona (MBOA) e o 2-benzoxazolinona (BOA) em cultivo solteiro e consorciado, e no nabo-forrageiro foi o flavonoide quercetina, em todas as épocas avaliadas. Ao longo do ciclo de cultivo, os maiores conteúdos de compostos fenólicos foram encontrados no estádio de alongamento (60 DAS) para a espécie centeio cultivada solteira e consorciada (9,33 e 8,22 mg g-1 MS) e no estádio de enchimento de grãos (100 DAS) para o nabo forrageiro em sistema de cultivo consorciado com centeio e aveia (3,24 e 3,83 mg g-1 MS). Não houve diferença nos conteúdos dos principais compostos quando a espécie foi cultivada solteira ou consorciada. Após o acamamento, houve redução nos conteúdos de MBOA, BOA e quercetina. A produção de MS de plantas daninhas foi menor aos 45 DAA em todos os tratamentos com resíduos de centeio e nabo, quando comparados com a testemunha. O consórcio do centeio com o nabo forrageiro é uma alternativa de manejo para o controle das plantas daninhas em sistemas agroecológicos, tanto pela barreira física exercida por essas espécies como pela presença de compostos fenólicos com potencial alelopático.

ABSTRACT: The identification of compounds with allelopathic potential produced by cover crops can assist in selecting species for weed management purposes in no-tillage systems. This study aimed to identify the main phenolic compounds with allelopathic potential in the shoot of rye (Secale cereale L.) and oilseed radish (Raphanus sativus L.) cover crops, as well as evaluate whether the cultivation system and phenological stage may influence secondary metabolite production and weed emergence. Samples of the shoot of these cover crops were collected at 60, 80, and 100 days after sowing (DAS) and 15 and 30 days after lodging (DAL) under field conditions. Weed emergence was evaluated at 45, 75, and 100 DAL of cover crops. The main compounds in rye were 6-methoxy-2-benzoxazolinone (MBOA) and 2-benzoxazolinone (BOA) under monocropping and intercropping, while flavonoid quercetin was found in oilseed radish at all evaluated times. During the growing cycle, the highest contents of phenolic compounds were found at the elongation stage (60 DAS) of rye under monocropping and intercropping systems (9.33 and 8.22 mg g-1 DM, respectively) and at grain filling stage (100 DAS) for oilseed radish intercropped with rye and black oat (3.24 and 3.83 mg g-1 DM, respectively). No differences were found in the contents of the main compounds when the species was grown under monocropping or intercropping systems. A reduction in the contents of MBOA, BOA, and quercetin was observed after lodging. Weed dry matter production was lower at 45 DAL in all treatments with rye and oilseed radish residues when compared to the control. The intercropping of rye with oilseed radish is an alternative management for weed control in agroecological systems due to the physical barrier created by these species and the presence of phenolic compounds with allelopathic potential.

Estudamos o problema bem conhecido dos dois capacitor através de uma nova perspectiva, com foco nos aspectos termodinâmicos do processo de descarga. O modelo de gás de elétrons livres é usado para descrever os níveis de energia dos elétrons nos dois condensadores no regime de baixas temperaturas. Consideramos uma troca de calor isotérmica entre o resistor e o reservatório térmico. Mesmo nesse caso limite, obtém-se uma variação positiva da entropia devido à descarga, apontando o caráter irreversível desse processo.

We study the well-known two-capacitor problem from a new perspective, focusing on the thermodynamic aspects of the discharge process. The free electron gas model is used to describe the electrons’ energy levels in both capacitors in the low temperature regime. We assume an isothermal heat exchange between the resistor and the heat reservoir. Even in this limiting case, we obtain a positive entropy variation due to the discharge, which points out the irreversibility of this process.

A planta Sideroxylon obtusifolium, conhecida popularmente como "quixabeira", é utilizada na medicina popular para o tratamento de processos inflamatórios e dolorosos. O objetivo deste trabalho foi avaliar a possível ação cicatrizante, bem como anti-inflamatória tópica, do extrato etanólico (EE) da entrecasca da S. obtusifolium no modelo de ferida e cicatrização cutânea. Para isso, ratos Wistar foram anestesiados, submetidos à incisão dorsal, e discos de esponja de álcool polivinílico foram inseridos subcutâneamente. Quarenta e oito horas após os animais foram eutanasiados avaliando-se medidas de tensão de ruptura nas cicatrizes da pele dorsal, a atividade de mieloperoxidase (MPO), e a contagem de células nos exsudatos das esponjas. A atividade sequestradora do radical 2,2-difenil-1-picrilhidrazil (DPPH) foi determinada para avaliar a capacidade antioxidante do EE. Observamos que a administração tópica, 2 vezes ao dia, do EE da S. obtusifolium (3-30 mg 0,4 mL-1 de creme Lanette(r)) não alterou a tensão de ruptura das cicatrizes. Entretanto, o EE da S. obtusifolium (30 mg 0,4 mL-1 de creme Lanette(r)) foi capaz de diminuir a atividade de MPO (p<0,01) e a contagem celular (p<0,05) no exsudato das esponjas, após 48 h da indução da ferida. O EE mostrou-se ativo como sequestrador do radical DPPH. Os valores de IC50 para o EE e ácido gálico foram semelhantes (1,04 ± 0,27 e 1,15 ± 0,02 μg mL-1 de DPPH, respectivamente). Concluímos que o EE da entrecasca da S. obtusifolium possui atividade anti-inflamatória através da administração tópica no modelo de cicatrização cutânea em ratos, além de seu potencial antioxidante.

The Sideroxylon obtusifolium is a medicinal plant known as “quixabeira” in Portuguese that has been used in folk medicine for the treatment of inflammatory and painful processes. The aim of this study was to evaluate the effect of the ethanol extract (EE) of S. obtusifolium on the cicatrization and local anti-inflammatory activities using a model of wound healing in rats. Wistar rats were submitted to a dorsal skin incision and polyvinyl alcohol sponge discs were implanted. Animals were euthanized after 48 h, and the tensile strength measurement at the wound site, the myeloperoxidase (MPO) activity and the leukocyte counts in the wound exudates were evaluated. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity was determined to evaluate the antioxidant capacity of the EE. We observed that the topical administration of the EE of S. obtusifolium (3-30 mg 0.4 mL-1 of Lanette® cream) twice a day did not alter the tensile strength, but it decreased the MPO activity (p<0,01)and leukocyte infiltration (p<0,05) after 48 h of induction of wound. The EE shows to be active as DPPH radical scavenger. The IC50 value for the EE was similar to the IC50 value of gallic acid (1.04 ± 0.27 and 1.15 ± 0.02 μg mL-1 DPPH, respectively). In conclusion, the EE of Sideroxylon obtusifolium shows local anti-inflammatory activity in the model of wound healing in rats, in addition to antioxidant potential.

We have shown that myocardial dysfunction induced by food restriction is related to calcium handling. Although cardiac function is depressed in food-restricted animals, there is limited information about the molecular mechanisms that lead to this abnormality. The present study evaluated the effects of food restriction on calcium cycling, focusing on sarcoplasmic Ca2+-ATPase (SERCA2), phospholamban (PLB), and ryanodine channel (RYR2) mRNA expressions in rat myocardium. Male Wistar-Kyoto rats, 60 days old, were submitted to ad libitum feeding (control rats) or 50% diet restriction for 90 days. The levels of left ventricle SERCA2, PLB, and RYR2 were measured using semi-quantitative RT-PCR. Body and ventricular weights were reduced in 50% food-restricted animals. RYR2 mRNA was significantly decreased in the left ventricle of the food-restricted group (control = 5.92 ± 0.48 vs food-restricted group = 4.84 ± 0.33, P < 0.01). The levels of SERCA2 and PLB mRNA were similar between groups (control = 8.38 ± 0.44 vs food-restricted group = 7.96 ± 0.45, and control = 1.52 ± 0.06 vs food-restricted group = 1.53 ± 0.10, respectively). Down-regulation of RYR2 mRNA expressions suggests that chronic food restriction promotes abnormalities in sarcoplasmic reticulum Ca2+ release.

Endometriosis is a progressive estrogen-dependent disease affecting women during their reproductive years. The objective of the present study was to investigate whether endometriosis is associated with stress parameters. We determined cortisol and prolactin levels in serum, peritoneal and follicular fluid from infertile women with endometriosis and fertile women without the disease. The extent of the disease was staged according to the revised American Fertility Society classification (1997). Serum and peritoneal fluid were collected from 49 women aged 19 to 39 years undergoing laparoscopy. Eighteen women had stage I-II endometriosis and 10 had stage III-IV. Controls were 21 women undergoing laparoscopy for tubal sterilization. Follicular fluid was obtained from 39 women aged 25-39 years undergoing in vitro fertilization (21 infertile women with endometriosis and 18 infertile women without endometriosis). Serum prolactin levels were significantly higher in infertile women with stage III-IV endometriosis (28.9 ± 2.1 ng/mL) than in healthy controls (13.2 ± 2.1 ng/mL). Serum cortisol levels were significantly higher in infertile women with stage III-IV endometriosis (20.1 ± 1.3 ng/mL) than in controls (10.5 ± 1.4 ng/mL). Cortisol and prolactin levels in follicular fluid and peritoneal fluid did not differ significantly between groups. The high levels of cortisol and prolactin in the serum from women with endometriosis might contribute to the subfertility frequently associated with the disease. Moreover, since higher levels of cortisol and prolactin are often associated with stress, it is probable that stress might contribute to the development of endometriosis and its progression to advanced stages of the disease.