Nitric oxide released from luminal s-nitroso-n-acetylcysteine increases gastric mucosal blood flow

Nitric oxide (NO)-mediated vasodilation plays a key role in gastric mucosal defense, and NO-donor drugs may protect against diseases associated with gastric mucosal blood flow (GMBF) deficiencies. In this study, we used the ex vivo gastric chamber method and Laser Doppler Flowmetry to characterize the effects of luminal aqueous NO-donor drug S-nitroso-N-acetylcysteine (SNAC) solution administration compared to aqueous NaNO2 and NaNO3 solutions (pH 7.4) on GMBF in Sprague-Dawley rats. SNAC solutions (600 μM and 12 mM) led to a rapid threefold increase in GMBF, which was maintained during the incubation of the solutions with the gastric mucosa, while NaNO2 or NaNO3 solutions (12 mM) did not affect GMBF. SNAC solutions (600 μM and 12 mM) spontaneously released NO at 37 °C at a constant rate of 0.3 or 14 nmol·mL-1·min-1, respectively, while NaNO2 (12 mM) released NO at a rate of 0.06 nmol·mL-1·min-1 and NaNO3 (12 mM) did not release NO. These results suggest that the SNAC-induced GMBF increase is due to their higher rates of spontaneous NO release compared to equimolar NaNO2 solutions. Taken together, our data indicate that oral SNAC administration is a potential approach for gastric acid-peptic disorder prevention and treatment.Nitric oxide (NO)-mediated vasodilation plays a key role in gastric mucosal defense, and NO-donor drugs may protect against diseases associated with gastric mucosal blood flow (GMBF) deficiencies. In this study, we used the ex vivo gastric chamber method and Laser Doppler Flowmetry to characterize the effects of luminal aqueous NO-donor drug S-nitroso-N-acetylcysteine (SNAC) solution administration compared to aqueous NaNO2 and NaNO3 solutions (pH 7.4) on GMBF in Sprague-Dawley rats. SNAC solutions (600 μM and 12 mM) led to a rapid threefold increase in GMBF, which was maintained during the incubation of the solutions with the gastric mucosa, while NaNO2 or NaNO3 solutions (12 mM) did not affect GMBF. SNAC solutions (600 μM and 12 mM) spontaneously released NO at 37 °C at a constant rate of 0.3 or 14 nmol·mL-1·min-1, respectively, while NaNO2 (12 mM) released NO at a rate of 0.06 nmol·mL-1·min-1 and NaNO3 (12 mM) did not release NO. These results suggest that the SNAC-induced GMBF increase is due to their higher rates of spontaneous NO release compared to equimolar NaNO2 solutions. Taken together, our data indicate that oral SNAC administration is a potential approach for gastric acid-peptic disorder prevention and treatment2034109412

Oxidative stress in rheumatoid arthritis: what the future might hold regarding novel biomarkers and add-on therapies

Numerous rheumatologic autoimmune diseases, among which rheumatoid arthritis, are chronic inflammatory diseases capable of inducing multiple cumulative articular and extra-articular damage, if not properly treated. Nevertheless, benign conditions may, similarly, exhibit arthritis as their major clinical finding, but with short-term duration instead, and evolve to spontaneous resolution in a few days to weeks, without permanent articular damage. Such distinction-self-limited arthritis with no need of immunosuppressive treatment or chronic arthritis at early stages?-represents one of the greatest challenges in clinical practice, once many metabolic, endocrine, neoplastic, granulomatous, infectious diseases and other autoimmune conditions may mimic rheumatoid arthritis. Indeed, the diagnosis of rheumatoid arthritis at early stages is a crucial step to a more effective mitigation of the disease-related damage. As a prototype of chronic inflammatory autoimmune disease, rheumatoid arthritis has been linked to oxidative stress, a condition in which the pool of reactive oxygen species increases over time, either by their augmented production, the reduction in antioxidant defenses, or the combination of both, ultimately implying compromise in the redox signaling. The exact mechanisms through which oxidative stress may contribute to the initiation and perpetuation of local (in the articular milieu) and systemic inflammation in rheumatoid arthritis, particularly at early stages, still remain to be determined. Furthermore, the role of antioxidants as therapeutic adjuvants in the control of disease activity seems to be overlooked, as a little number of short studies addressing this issue is currently found. Thus, the present review focuses on the binomial rheumatoid arthritis-oxidative stress, bringing insights into their pathophysiological relationships, as well as the implications of potential diagnostic oxidative stress biomarkers and therapeutic interventions directed to the oxidative status in patients with rheumatoid arthritis

Response surface for biodiesel production from soybean oil by ethylic route

Petroleum has been the most consumed energy source in the world, but it tends to run out due its non-renewable character. Among biofuels, biodiesel has emerged as the main candidate to substitute petroleum diesel. The present study aimed to identify the maximum yield point of biodiesel production by generating a response surface using molar ratio, temperature and agitation time as independent variables, and yield as a dependent variable. From the response surface, it is observed that the increase in temperature and reaction time leads to reduced yield. The configuration that resulted in maximum yield of 93.30% was 12:1 molar ratio, 30 °C temperature and 30-minute reaction time. From the chromatographic analysis it was possible to identify five different fatty acids in the composition of the biodiesels. Total saturated fatty acids (palmitic and stearic acids) ranged from 41.53% to 42.09% and total unsaturated fatty acids including monounsaturated and polyunsaturated fatty acids (oleic, linoleic and linolenic acids) ranged from 57.92% to 58.48%. According to the results of the physicochemical analyses, the specific mass at 68°F is in agreement with Brazilian, American and European specifications, ranging from 877.46 kg m-3 to 879.64 kg m-3 . The kinematic viscosity at 104 °F ranged from 4.49 mm² s -1 to 4.82 mm² s -1 . The acid value obtained did not vary within the limits established by the norms, and values between 0.54 and 2.74 mg KOH g -1 were observed

Silicone resin to improve corrosion resistance of Zn and ZnFe coated steel

Chromatation pre-treatments have been widely used to improve galvanized steel corrosion resistance. However, due to the high toxicity of chromate ions, chromatation pre-treatments tend to be banned and, in last years, alternative coating systems are under investigation. Recently, polysiloxanes have been developed for application as coatings. Among them, and due to their specific properties, such as hardness, chemical resistance and hydrophobicity, silicone resins may be considered as promising substitutes for chromatation pre-treatments. In this work silicone films, obtained from the hydrolysis of a methoxy functional silicone reactive intermediate, were applied on galvanized steel and on steel electroplated with a ZnFe alloy. Electrochemical techniques were used to characterize the degradation behavior of the samples. These consisted on the monitoring of the open circuit potential (OCP), and on the potentiodynamic polarization of the samples, which was performed in a 3% NaCl aqueous solution. Additionally, electrochemical impedance spectroscopy (EIS) was used as a complementary technique for the evaluation of the corrosion mechanisms of the coating system. SEM and EDS were employed to inspect the surface of the samples before and after the electrochemical tests. EIS data was fitted to an equivalent circuit from which the electrochemical parameters were obtained. Results show the protective character of the resin films, when compared with uncovered specimens. The capacitance of the films increased with the immersion time, in accordance to the behavior expected for an organic film. The overall performance of the coating systems appears to be highly dependent on the type of metallic coating applied to the steel. During the first three days of immersion the coatings applied upon galvanized steel showed larger |Z| values when compared with those applied to the electroplated steel, indicating a superior corrosion resistance of the former. However, after that time, an abrupt drop of |Z| is observed in the film applied on galvanized steel. In comparison, the coating system involving ZnFe alloy evidences a better stability throughout the immersion time.1623Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Experimental model to study intervertebral disc herniation

OBJETIVO: Apresentar um modelo experimental de hérnia de disco e sua validação para estudo da hiperalgesia mecânica e térmica produzidas pelo contato do núcleo pulposo (NP) com as estruturas nervosas envolvidas nessa afecção. MÉTODOS: Foram utilizados ratos Wistar, sendo o NP autólogo retirado da região sacrococcígea e depositado sobre a dura-máter, raiz nervosa ou gânglios das raízes dorsais L4, L5 ou L6. Os experimentos foram divididos em quatro etapas: 1ª) determinação da estrutura nervosa mais sensível ao contato com o NP; 2ª) identificação do melhor nível lombar para a indução da hiperalgesia; 3ª) determinação da ausência de lesão motora; e 4ª) determinação da influência do procedimento cirúrgico no desenvolvimento do processo inflamatório. A hiperalgesia foi avaliada nos testes de von Frey eletrônico e de Hargreaves e a função motora, pelo teste de rota-rod. RESULTADOS: O NP induziu hiperalgesia de maior intensidade na pata quando em contato com o gânglio da raiz dorsal (GRD) do que em contato com a dura-máter ou a raiz nervosa. Quando em contato com o GRD-L5, o NP induziu hiperalgesia ainda maior que a induzida pelo contato com os GRDs L4 e L6. Não foram observadas lesão motora e influência do processo inflamatório cirúrgico sobre a hiperalgesia. CONCLUSÃO: O GRD é a estrutura mais sensível aos componentes do NP para a produção da hiperalgesia, sendo o quinto nível lombar o que apresentou maior alteração nas sensibilidades mecânica e térmica avaliadas na pata dos animais, de acordo com os métodos utilizados.OBJECTIVE:The purpose of this study is to present an experimental model of disc herniation and to validate such model to study mechanic and thermal hyperalgesia produced by the contact of the nucleus pulposus (NP) with nerve structures involved in this condition. METHODS: The authors used Wistar rats, the autologous NP being removed from the sacrococcygeal region and deposited on the dura mater, nerve root, or L4, L5, or L6 dorsal root ganglia. The experiments were divided into four steps: 1) determining the nerve structure that is the most sensitive to the contact with NP; 2) identifying the best lumbar level to induce hyperalgesia; 3) determining absence of a motor lesion; and 4) determining the impact of the surgical procedure upon the inflammatory process. Hyperalgesia was evaluated by the von Frey electronic test and the Hargreaves test, and the motor function was evaluated by the rota-rod test. RESULTS: NP induced higher intensity hyperalgesia in the paw when it was in contact with the dorsal root ganglion (GRD) than when it was in contact with the dura mater or the nerve root. Contact with GRD-L5, led NP to induce even higher hyperalgesia than that induced in the contact with L4 and L6 GRDs. No motor lesion and impact of the surgical inflammatory process on hyperalgesia were observed. CONCLUSION: GRD is the structure that is most sensitive to NP components to produce hyperalgesia, the fifth lumbar level being that showed the greatest change in the mechanic and thermal sensitivities evaluated in the paws of the animals, under the methods used

Metabolic profiles of six African cultivars of cassava (Manihot esculenta Crantz) highlight bottlenecks of root yield

Open Access Article; Published online: 17 Jan 2020Cassava is an important staple crop in sub‐Saharan Africa, due to its high productivity even on nutrient poor soils. The metabolic characteristics underlying this high productivity are poorly understood including the mode of photosynthesis, reasons for the high rate of photosynthesis, the extent of source/sink limitation, the impact of environment, and the extent of variation between cultivars. Six commercial African cassava cultivars were grown in a greenhouse in Erlangen, Germany, and in the field in Ibadan, Nigeria. Source leaves, sink leaves, stems and storage roots were harvested during storage root bulking and analyzed for sugars, organic acids, amino acids, phosphorylated intermediates, minerals, starch, protein, activities of enzymes in central metabolism and yield traits. High ratios of RuBisCO:phosphoenolpyruvate carboxylase activity support a C3 mode of photosynthesis. The high rate of photosynthesis is likely to be attributed to high activities of enzymes in the Calvin–Benson cycle and pathways for sucrose and starch synthesis. Nevertheless, source limitation is indicated because root yield traits correlated with metabolic traits in leaves rather than in the stem or storage roots. This situation was especially so in greenhouse‐grown plants, where irradiance will have been low. In the field, plants produced more storage roots. This was associated with higher AGPase activity and lower sucrose in the roots, indicating that feedforward loops enhanced sink capacity in the high light and low nitrogen environment in the field. Overall, these results indicated that carbon assimilation rate, the K battery, root starch synthesis, trehalose, and chlorogenic acid accumulation are potential target traits for genetic improvement

(-)-tarchonanthuslactone exerts a blood glucose-increasing effect in experimental type 2 diabetes mellitus

A number of studies have proposed an anti-diabetic effect for tarchonanthuslactone based on its structural similarity with caffeic acid, a compound known for its blood glucose-reducing properties. However, the actual effect of tarchonanthuslactone on blood glucose level has never been tested. Here, we report that, in opposition to the common sense, tarchonanthuslactone has a glucose-increasing effect in a mouse model of obesity and type 2 diabetes mellitus. The effect is acute and non-cumulative and is present only in diabetic mice. In lean, glucose-tolerant mice, despite a slight increase in blood glucose levels, the effect was not significant.A number of studies have proposed an anti-diabetic effect for tarchonanthuslactone based on its structural similarity with caffeic acid, a compound known for its blood glucose-reducing properties. However, the actual effect of tarchonanthuslactone on blood glucose level has never been tested. Here, we report that, in opposition to the common sense, tarchonanthuslactone has a glucose-increasing effect in a mouse model of obesity and type 2 diabetes mellitus. The effect is acute and non-cumulative and is present only in diabetic mice. In lean, glucose-tolerant mice, despite a slight increase in blood glucose levels, the effect was not significant2035038504

Productive efficiency and density and viscosity studies of biodiesels from vegetable oil mixtures

Received: January 31st, 2021 ; Accepted: April 10th, 2021 ; Published: April 29th, 2021 ; Correspondence: [email protected] in Brazil the minimum content of biodiesel in mixtures is 11% and, according to Brazilian laws, the goal is to reach 15% in volume in diesel fuel available for final consumers by 2023. Therefore, studies about different matrices of biodiesel and distinct mixtures are essential. The present work had two goals, the first one was to analyse physico-chemical properties of 16 biofuels produced from soybean and cotton oils, using S10 diesel, in mixtures B8, B10, B20 and B30. The second goal was to verify the vantages and disadvantages of biodiesel production through prior mixing of the oils, before and after the transesterification process. All biofuels produced presented results of specific mass values at 20 °C and kinematic viscosity at 40 °C within the limits established by ANP Resolution no 30/2016 and International Resolutions. The soybean B20 biofuel showed the best overall results, with the second highest production yield of 65.36%, the fifth lowest kinematic viscosity with 3.48 mm s -1 . The mixture of soybean and cotton oils before the transesterification process presented the highest production yield when compared with the production from a single oil or biodiesel mixtures. The results found proved to be satisfactory and corroborate to continue with the increase of biodiesel in the mixture with diesel to B15 until 2023 and support the possibility of planning for a gradual increase of this mixture in the following years

A student-centered approach for developing active learning: the construction of physical models as a teaching tool in medical physiology

BACKGROUND: Teaching physiology, a complex and constantly evolving subject, is not a simple task. A considerable body of knowledge about cognitive processes and teaching and learning methods has accumulated over the years, helping teachers to determine the most efficient way to teach, and highlighting student's active participation as a means to improve learning outcomes. In this context, this paper describes and qualitatively analyzes an experience of a student-centered teaching-learning methodology based on the construction of physiological-physical models, focusing on their possible application in the practice of teaching physiology. METHODS: After having Physiology classes and revising the literature, students, divided in small groups, built physiological-physical models predominantly using low-cost materials, for studying different topics in Physiology. Groups were followed by monitors and guided by teachers during the whole process, finally presenting the results in a Symposium on Integrative Physiology. RESULTS: Along the proposed activities, students were capable of efficiently creating physiological-physical models (118 in total) highly representative of different physiological processes. The implementation of the proposal indicated that students successfully achieved active learning and meaningful learning in Physiology while addressing multiple learning styles. CONCLUSION: The proposed method has proved to be an attractive, accessible and relatively simple approach to facilitate the physiology teaching-learning process, while facing difficulties imposed by recent requirements, especially those relating to the use of experimental animals and professional training guidelines. Finally, students' active participation in the production of knowledge may result in a holistic education, and possibly, better professional practices