11 resultados para Licitação do tipo menor preço
em Universidade Federal do Rio Grande do Norte(UFRN)
Resumo:
Heparin is a pharmaceutical animal widely used in medicine due to its potent anticoagulant effect. Furthermore, it has the ability to inhibit the proliferation, invasion and adhesion of cancer cells to vascular endothelium. However, its clinical applicability can be compromised by side effects such as bleeding. Thus, the search for natural compounds with low bleeding risk and possible therapeutic applicability has been targeted by several research groups. From this perspective, this study aims to evaluate the hemorrhagic and anticoagulant activities and citotoxic effect for different tumor cell lines (HeLa, B16-F10, HepG2, HS-5,) and fibroblast cells (3T3) of the Heparin-like from the crab Chaceon fenneri (HEP-like). The HEP-like was purified after proteolysis, ion-exchange chromatography, fractionation with acetone and characterized by electrophoresis (agarose gel) and enzymatic degradation. Hep-like showed eletroforetic behavior similar to mammalian heparin, and high trisulfated /Nacetylated disaccharides ratio. In addition, HEP-like presented low in vitro anticoagulant activity using aPTT and a minor hemorrhagic effect when compared to mammalian heparin. Furthermore, the HEP-like showed significant cytotoxic effect (p<0.001) on HeLa, HepG2 and B16-F10 tumor cells with IC50 values of 1000 ug/mL, after incubation for 72 hours. To assess the influence of heparin-like on the cell cycle in HeLa cells, analysis was performed by flow cytometry. The results of this analysis showed that HEP-like influence on the cell cycle increasing S phase and decreasing phase G2. Thus, these properties of HEP-like make these compounds potential therapeutic agents
Resumo:
Heparin, a sulfated polysaccharide, was the first compound used as an anticoagulant and antithrombotic agent. Due to their structural characteristics, also has great potential anti-inflammatory, though such use is limited in inflammation because of their marked effects on coagulation. The occurrence of heparin-like compounds that exhibit anticoagulant activity decreased in aquatic invertebrates, such as crab Goniopsis cruentata, sparked interest for the study of such compounds as anti-inflammatory drugs. Therefore, the objective of this study was to evaluate the potential modulator of heparin-like compound extracted from Goniopsis cruentata in inflammatory events, coagulation, and to evaluate some aspects of its structure. The heparin-type compound had a high degree of N-sulphation in its structure, being able to reduce leukocyte migration into the peritoneal cavity at lower doses compared to heparin and diclofenac sodium (anti-inflammatory commercial). Furthermore, it was also able to inhibit the production of nitric oxide and tumor necrosis factor alpha by activated macrophages, inhibited the activation of the enzyme neutrophil elastase in low concentrations and showed a lower anticoagulant effect in high doses as compared to porcine mucosal heparin. Because of these observations, the compound extracted from crab Goniopsis cruentata can be used as a structural model for future anti-inflammatory agents
Resumo:
The partial fixed prosthodontics restoration is used to rehabilitate form and function of partial or total compromised teeth, having to remain permanently joined to remainder tooth. The most useful material on prosthodontics is the feldspar porcelain, commercialized as aluminosilicate powders. Dental porcelains are presented with limited mechanical properties to rehabilitate extensive spaces. The association with Ni-Cr metallic systems (metal-ceramic system) allows that the metallic substructure compensates the fragile porcelain nature, preserving the thermal insulation and aesthetics desirable, as well as reducing the possibility of cracking during matication efforts. Cohesive flaws by low mechanical strength connect the metallic substructure to the oral environment, characterized by a electrolytic solution (saliva), by aggressive temperature, pH cyclic changes and mechanical requests. This process results on ionic liberation that could promote allergic or inflammatory responses, and/or clinical degradation of ceramometal system. The aim of this study was to evaluate the presence of an intermediate titanium layer on the microscopic fracture behavior of porcelains on ceramometal systems. Plasma deposition of titanium films result in regular passivating oxide layers which act as barriers to protect the metallic substrate against the hazardous effects of corrosive saliva. Tribocorrosion tests were performed to simulate the oral environment and mechanical stress, making it possible the early detection of crack formation and growth on metal-ceramic systems, which estimate the adherence between the compounds of this system. Plain samples consisting of dental feldspar porcelain deposited either onto metallic substrates or titanium films were fired and characterized by scanning electron microscopy. The result showed that the titanium film improved the adherence of the system compared to conventional metal-ceramic interfaces, thus holding crack propagation
Resumo:
Sexually transmitted diseases (STDs) are among the largest public health problems, especially in developing countries. The acquisition of these infections during early sexual activity is common and many infections have a benign course. However, in some pathogens remain in the state of latency can be reactivated and cause productive infection that may progress to severe forms. In addition, some of them are transmitted vertically resulting in congenital infection, causing immediate damage or long-term child. The classic risk factors for sexually transmitted agents are: early onset of sexual and reproductive health, multiple sexual partners throughout life, use of oral contraceptives and co-infections with different pathogens. We present the results of a cross-sectional study aimed to estimate the prevalence of genital infection by human papillomavirus (HPV), Herpes simplex virus (HSV) and Chlamydia trachomatis (CT) in a segment of the female population of the metropolitan area Christmas, among those who enrolled voluntarily sought, Basic Health Units for the examination of cancer screening cervix in the period 2008 to 2010. All participants, a total of 261 women answered a standard questionnaire by which identified the socio-demographic characteristics, classical risk factors for STDs, reproductive and sexual activity and smoking. Of each patient were obtained two samples, one for the completion of the Pap test for detection of cellular changes and the other processed for DNA extraction and analyzed by PCR (polymerase chain reaction) to detect the three pathogens studied. The population of the study was composed of sexually active women aged between 13 and 79 years, mean 38.7 years, most of them being married, low education levels and low incomes. The majority (87%) had normal results on cytology and only 2.7% had low-grade cytological abnormalities. Prevalence rates were 37.9% for HPV, 4.6% for CT and 26% for HSV. HPV prevalence was higher in women under 25, unmarried and in those who had multiple sexual partners. Women with simultaneous infection by HSV-1 and 2 had higher prevalence of HPV infection. The prevalence of HSV infection showed no association whatsoever with the risk factors analyzed and HSV-1 was the predominant type among the cases of genital HSV infection. The overall prevalence of C. Trachomatis was relatively low, thus providing greater value in younger women aged less than or equal to 20 years
Resumo:
Herpes simplex is a virus that can be transmitted sexually and is potentially associated with vertical transmission. This study evaluated the prevalence of genital infection by herpes simplex virus (HSV) types 1 and 2 in pregnant and nonpregnant care in the city of Natal / RN, including a total of 222 women, 92 pregnant and 130 nonpregnant. The participants answered a questionnaire to obtain data and socio-demographic characteristics, as well as potential risk factors for sexually transmitted diseases. After the interview, we collected two cervical specimens, one for the Pap test and the other for DNA extraction and analyzed by polymerase chain reaction (PCR) to detect both virus serotypes. Then the women underwent a clinical examination by colposcopy. For statistical analysis, we used the chi-square and logistic regression by SSPS 17.0 Statistic. Most women were up to 30 years of age, nonwhite ethnicity, married, elementary education, family income below the poverty level; initiated sexual activity with age up to 18 years; had more than one sexual partner lifelong and was not pregnant, but has had at least one child. The HSV-1 showed a prevalence of 26.1% among pregnant women and 30.0% in non-pregnant women. While HSV-2 prevalence was found with 10.9% and 19.2% in pregnant and nonpregnant women, respectively. The largest proportion of morphological changes of the uterine cervix was detected among nonpregnant women, both in cytology and in colposcopy. The women were nonwhite ethnicity, married, became pregnant aged less than or equal to 18 years and who had one to two pregnancies had a lower risk of acquiring genital HSV infection. There was a high prevalence of genital HSV infection, HSV-1 is more prevalent than HSV-2. No association was found between morphological changes of the uterine cervix and the presence of the virus in pregnant and nonpregnant women, nor between genital HSV infection and the classic risk factors for sexually transmitted diseases
Resumo:
The caffeine is a mild psychostimulant that has positive cognitive effects at low doses, while promotes detrimental effects on these processes at higher doses. The episodic-like memory can be evaluated in rodents through hippocampus-dependent tasks. The dentate gyrus is a hippocampal subregion in which neurogenesis occurs in adults, and it is believed that this process is related to the function of patterns separation, such as the identification of spatial and temporal patterns when discriminating events. Furthermore, neurogenesis is influenced spatial and contextual learning tasks. Our goal was to evaluate the performance of male Wistar rats in episodic-like tasks after acute or chronic caffeine treatment (15mg/kg or 30mg/kg). Moreover, we assessed the chronic effect of the caffeine treatment, as well as the influence of the hippocampus-dependent learning tasks, on the survival of new-born neurons at the beginning of treatment. For this purpose, we used BrdU to label the new cells generated in the dentate gyrus. Regarding the acute treatment, we found that the saline group presented a tendency to have better spatial and temporal discrimination than caffeine groups. The chronic caffeine group 15 mg/kg (low dose) showed the best discrimination of the temporal aspect of episodic-like memory, whereas the chronic caffeine group 30mg/kg (high dose) was able to discriminate temporal order, only in a condition of greater difficulty. Assessment of neurogenesis using immunohistochemistry for evaluating survival of new-born neurons generated in the dentate gyrus revealed no difference among groups of chronic treatment. Thus, the positive mnemonic effects of the chronic caffeine treatment were not related to neuronal survival. However, another plastic mechanism could explain the positive mnemonic effect, given that there was no improvement in the acute caffeine groups
Resumo:
One of the main applications of methane is in the production of syngas, a mixture of hydrogen and carbon monoxide. Procedures used in this process are steam reforming, CO2 reforming, partial oxidation and autothermal reforming. The present study evaluated and compared the behavior of nickel catalysts supported on mixed oxides of cerium and manganese in the partial oxidation of methane with that of nickel catalysts supported on mixed oxides of cerium and zirconium. Mixed oxides of cerium and zirconium or cerium and manganese were synthesized using two different preparation methods, the polymeric precursor based on Pechini method and combustion reaction using a microwave. This was followed by impregnation with nickel content of 15 %. Samples were calcined at 300, 800 and 900 °C and characterized by specific surface area (SSA), X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM), temperature programmed reduction (TPR) and the reaction of partial oxidation of methane. The specific areas of samples decrease with the rise in calcination temperature and after nickel impregnation. Metal-cerium solid solution was formed and the presence of other manganese species outside the solid solution structure was confirmed in the compound with the highest amounts of manganese oxides showed. With regard to scanning electron microscopy, supports based on cerium and zirconium prepared by Pechini method exhibited agglomerated particles without uniform geometry or visible pores on the surface. However, compounds containing manganese presented empty spaces in its structure. Through synthesis by combustion reaction, morphology acquired independently of the proposed composition demonstrated greater porosity in relation to Pechini synthesis. Although catalysts were prepared using different synthesis methods, the insertion of nickel showed very similar reduction profiles (TPR). In relation to nickel catalysts supported on mixed oxide of cerium and zirconium, there is an initial reduction of NiO species that present certain interaction with the support. This is followed by the reduction of Ce4+ in Ce3+ surface, with subsequent bulk reduction. For catalysts containing manganese, a reduction of nickel oxide species occurs, followed by two stages of reduction for species Mn2O3 in Mn3O4 and Mn3O4 in MnO, with subsequent reduction of bulk. With respect to partial oxidation reactions, the nickel catalyst supported on mixed oxide of cerium and zirconium, prepared using the Pechini method, exhibited CH4 conversion of approximately 80 %, with conversion of 81 % when prepared by combustion. This behavior continued for 10 hours of reaction. Manganese content was also found to directly influence catalytic activity of materials; the greater the manganese oxide content, the faster deactivation and destabilization occurred in the catalyst. In both synthesis methods, the nickel catalyst supported on mixed oxide of cerium and zirconium maintained an H2/CO ratio very close to 2 during the 10 hours of partial oxidation reaction. Samples containing manganese displayed smaller H2/CO ratios and lower performance in partial oxidation.
Resumo:
The chemical recycling of polyolefins has been the focus of increasing attention owing potential application as a fuel and as source chemicals. The use of plastic waste contributes to the solution of pollution problems.The use of catalysts can enhance the thermal degradation of synthetic polymers, which may be avaliated by Themogravimetry (TG) and mass spectrometry (MS) combined techniques. This work aims to propose alternatives to the chemistry recycling of low-density polyethylene (LDPE) on mesoporous silica type SBA-15 and AlSBA-15.The mesoporous materials type SBA-15 and AlSBA-15 were synthesized through the hydrothermal method starting from TEOS, pseudobohemite, cloridric acid HCl and water. As structure template was used Pluronic P123. The syntheses were accomplished during the period of three days. The best calcination conditions for removal of the organic template (P123) were optimized by thermal analysis (TG/DTG) and through analyses of Xray diffraction (XRD), infrared spectroscopy (FT-IR), nitrogen adsorption and scanning electron microscopy (SEM) was verified that as much the hydrothermal synthesis method as the calcination by TG were promising for the production of mesoporous materials with high degree of hexagonal ordination. The general analysis of the method of Analog Scan was performed at 10oC/min to 500 oC to avoid deterioration of capillary with very high temperatures. Thus, with the results, we observed signs mass/charge more evident and, using the MID method, was obtained curve of evolution of these signals. The addition of catalysis produced a decrease in temperature of polymer degradation proportional to the acidity of the catalyst. The results showed that the mesoporous materials contributed to the formation of compounds of lower molecular weight and higher value in the process of catalytic degradation of LDPE, representing an alternative to chemical recycling of solid waste
Resumo:
Heparin is a pharmaceutical animal widely used in medicine due to its potent anticoagulant effect. Furthermore, it has the ability to inhibit the proliferation, invasion and adhesion of cancer cells to vascular endothelium. However, its clinical applicability can be compromised by side effects such as bleeding. Thus, the search for natural compounds with low bleeding risk and possible therapeutic applicability has been targeted by several research groups. From this perspective, this study aims to evaluate the hemorrhagic and anticoagulant activities and citotoxic effect for different tumor cell lines (HeLa, B16-F10, HepG2, HS-5,) and fibroblast cells (3T3) of the Heparin-like from the crab Chaceon fenneri (HEP-like). The HEP-like was purified after proteolysis, ion-exchange chromatography, fractionation with acetone and characterized by electrophoresis (agarose gel) and enzymatic degradation. Hep-like showed eletroforetic behavior similar to mammalian heparin, and high trisulfated /Nacetylated disaccharides ratio. In addition, HEP-like presented low in vitro anticoagulant activity using aPTT and a minor hemorrhagic effect when compared to mammalian heparin. Furthermore, the HEP-like showed significant cytotoxic effect (p<0.001) on HeLa, HepG2 and B16-F10 tumor cells with IC50 values of 1000 ug/mL, after incubation for 72 hours. To assess the influence of heparin-like on the cell cycle in HeLa cells, analysis was performed by flow cytometry. The results of this analysis showed that HEP-like influence on the cell cycle increasing S phase and decreasing phase G2. Thus, these properties of HEP-like make these compounds potential therapeutic agents
Resumo:
Heparin, a sulfated polysaccharide, was the first compound used as an anticoagulant and antithrombotic agent. Due to their structural characteristics, also has great potential anti-inflammatory, though such use is limited in inflammation because of their marked effects on coagulation. The occurrence of heparin-like compounds that exhibit anticoagulant activity decreased in aquatic invertebrates, such as crab Goniopsis cruentata, sparked interest for the study of such compounds as anti-inflammatory drugs. Therefore, the objective of this study was to evaluate the potential modulator of heparin-like compound extracted from Goniopsis cruentata in inflammatory events, coagulation, and to evaluate some aspects of its structure. The heparin-type compound had a high degree of N-sulphation in its structure, being able to reduce leukocyte migration into the peritoneal cavity at lower doses compared to heparin and diclofenac sodium (anti-inflammatory commercial). Furthermore, it was also able to inhibit the production of nitric oxide and tumor necrosis factor alpha by activated macrophages, inhibited the activation of the enzyme neutrophil elastase in low concentrations and showed a lower anticoagulant effect in high doses as compared to porcine mucosal heparin. Because of these observations, the compound extracted from crab Goniopsis cruentata can be used as a structural model for future anti-inflammatory agents
Resumo:
The partial fixed prosthodontics restoration is used to rehabilitate form and function of partial or total compromised teeth, having to remain permanently joined to remainder tooth. The most useful material on prosthodontics is the feldspar porcelain, commercialized as aluminosilicate powders. Dental porcelains are presented with limited mechanical properties to rehabilitate extensive spaces. The association with Ni-Cr metallic systems (metal-ceramic system) allows that the metallic substructure compensates the fragile porcelain nature, preserving the thermal insulation and aesthetics desirable, as well as reducing the possibility of cracking during matication efforts. Cohesive flaws by low mechanical strength connect the metallic substructure to the oral environment, characterized by a electrolytic solution (saliva), by aggressive temperature, pH cyclic changes and mechanical requests. This process results on ionic liberation that could promote allergic or inflammatory responses, and/or clinical degradation of ceramometal system. The aim of this study was to evaluate the presence of an intermediate titanium layer on the microscopic fracture behavior of porcelains on ceramometal systems. Plasma deposition of titanium films result in regular passivating oxide layers which act as barriers to protect the metallic substrate against the hazardous effects of corrosive saliva. Tribocorrosion tests were performed to simulate the oral environment and mechanical stress, making it possible the early detection of crack formation and growth on metal-ceramic systems, which estimate the adherence between the compounds of this system. Plain samples consisting of dental feldspar porcelain deposited either onto metallic substrates or titanium films were fired and characterized by scanning electron microscopy. The result showed that the titanium film improved the adherence of the system compared to conventional metal-ceramic interfaces, thus holding crack propagation