RESUMO
OBJECTIVES: This study aimed to assess the nutritional quality of food products marketed at children, with and without nutrient claims, using two different approaches. METHODS: Analyses were performed based on a data set with food composition and labelling data from every packaged food marketed at children sold in a major Brazilian supermarket (n=535). Foods were classified as 'healthier' and 'less healthy' according to the UK/Ofcom nutrient profile model and to the NOVA classification based on the level of food processing. Pearson's χ2 test was used to compare proportions between models. Agreement was assessed using Cohen's κ-statistic (P<0.05). RESULTS: The NOVA model was stricter than the UK/Ofcom model, classifying more products as 'less healthy' (91.4%) compared with the nutrient profile-based model (75.0%; P<0.001). Agreement between models was 79.4% (k=0.30), because 72.9% (n=390) of products were categorised as 'less healthy' by both models, and 6.5% (n=35) as 'healthier'. Half of the food products marketed at children from the database (270; 50.5%) bore nutrient claims. From these products with nutrient claims, 95.9% (92.8-98.0) were classified as 'less healthy' by the NOVA model, whereas this percentage was 74.1% (68.4-79.2) according to the UK/Ofcom model (P<0.05). CONCLUSIONS: The high number of foods with low nutritional quality being marketed at children via product packaging and nutrient claims should be of concern to policy makers wanting to improve children's diets and to tackle childhood obesity. The implementation of nutritional quality criteria to ensure that foods targeted at children should be eligible to bear nutrient claims on their labels could avoid a situation where claims mask the overall nutritional status of a food.
Assuntos
Rotulagem de Alimentos/legislação & jurisprudência , Embalagem de Alimentos/legislação & jurisprudência , Marketing/legislação & jurisprudência , Política Nutricional , Valor Nutritivo , Brasil , Criança , Fenômenos Fisiológicos da Nutrição Infantil , Comportamento de Escolha , Estudos Transversais , Análise de Alimentos , Rotulagem de Alimentos/ética , Rotulagem de Alimentos/normas , Fidelidade a Diretrizes , Promoção da Saúde , Humanos , Marketing/ética , Marketing/normasRESUMO
Viruses are associated with several human diseases that infect a large number of individuals, hence directly affecting global health and economy. Owing to the lack of efficient vaccines, antiviral therapy and emerging resistance strains, many viruses are considered as a potential threat to public health. Therefore, researches have been developed to identify new drug candidates for future treatments. Among them, antiviral research based on natural molecules is a promising approach. Phospholipases A2 (PLA2s) isolated from snake venom have shown significant antiviral activity against some viruses such as Dengue virus, Human Immunodeficiency virus, Hepatitis C virus and Yellow fever virus, and have emerged as an attractive alternative strategy for the development of novel antiviral therapy. Thus, this review provides an overview of remarkable findings involving PLA2s from snake venom that possess antiviral activity, and discusses the mechanisms of action mediated by PLA2s against different stages of virus replication cycle. Additionally, molecular docking simulations were performed by interacting between phospholipids from Dengue virus envelope and PLA2s from Bothrops asper snake venom. Studies on snake venom PLA2s highlight the potential use of these proteins for the development of broad-spectrum antiviral drugs.
Assuntos
Antivirais/farmacologia , Fosfolipases A2/farmacologia , Venenos de Serpentes/enzimologia , Serpentes/metabolismo , Animais , Vírus da Dengue/efeitos dos fármacos , Farmacorresistência Viral/efeitos dos fármacos , HIV/efeitos dos fármacos , Hepacivirus/efeitos dos fármacos , Simulação de Acoplamento Molecular , Proteínas de Répteis/farmacologia , Vírus da Febre Amarela/efeitos dos fármacosRESUMO
Peptides derived from a phage display library may mimic essential features of epitopes (mimotopes), including their immunogenicity. A recombinant peptide library of 12 amino acids displayed on the phage capsid was used to obtain peptides that mimic epitopes of antigens that are reactive to specific polyclonal antibodies anti-neuwiedase (NEU), a toxin from Bothrops neuwiedi snake venom. These polyclonal antibodies are protective against NEU activity and were used as target for the peptide library biopannings, resulting in the selection of 80 peptides. Antibody-binding epitopes were obtained by sequence alignment with the primary and tertiary structures of the NEU protein. Antigenicity and specificity of the mimotopes mixture were confirmed by dot blot, immuno dot blot, plaque reduction and Western blot assays. Their immunogenicity was demonstrated by immunization of BALB/c mice and ELISA tests. The NEU toxin is an important antigen that has many common structural regions to several toxic venom metalloproteinases, in which two epitope regions have been detected. The two mapped epitopes were found in primary sequences of several snake venom toxins, thus demonstrating the potential application of these NEU mimotopes as possible antigen components that are toxicity free.
Assuntos
Bothrops/fisiologia , Venenos de Crotalídeos/enzimologia , Epitopos/química , Epitopos/imunologia , Metaloendopeptidases/metabolismo , Venenos de Víboras/metabolismo , Sequência de Aminoácidos , Animais , Antígenos , Biologia Computacional , Venenos de Crotalídeos/imunologia , Epitopos/genética , Metaloendopeptidases/química , Camundongos , Modelos Moleculares , Biblioteca de Peptídeos , Peptídeos , Ligação Proteica , Conformação Proteica , Coelhos , Venenos de Víboras/químicaRESUMO
Snake venom metalloproteinases (SVMPs) have been extensively studied and their effects associated with the local bleeding observed in human accidents by viper snakes. Representatives of P-I and P-III classes of SVMPs similarly hydrolyze extracellular matrix proteins or coagulation factors while only P-III SVMPs induce significant hemorrhage in experimental models. In this work, the effects of P-I and P-III SVMPs on plasma proteins and cultures of muscle and endothelial cells were compared in order to enlighten the mechanisms involved in venom-induced hemorrhage. To reach this comparison, BnP1 was isolated from B. neuwiedi venom and used as a weakly hemorrhagic P-I SVMPs and jararhagin was used as a model of potently hemorrhagic P-III SVMP. BnP1 was isolated by size exclusion and anion-exchange chromatographies, showing apparent molecular mass of approximately 24kDa and sequence similarity with other members of SVMPs, which allowed its classification as a group P-I SVMP. The comparison of local effects induced by SVMPs showed that BnP1 was devoid of significant myotoxic and hemorrhagic activities and jararhagin presented only hemorrhagic activity. BnP1 and jararhagin were able to hydrolyze fibrinogen and fibrin, although the latter displayed higher activity in both systems. Using HUVEC primary cultures, we observed that BnP1 induced cell detachment and a decrease in the number of viable endothelial cells in levels comparable to those observed by treatment with jararhagin. Moreover, both BnP1 and jararhagin induced apoptosis in HUVECs while only a small increase in LDH supernatant levels was observed after treatment with jararhagin, suggesting that the major mechanism involved in endothelial cell death is apoptosis. Jararhagin and BnP1 induced little effects on C2C12 muscle cell cultures, characterized by a partial detachment 24h after treatment and a mild necrotic effect as evidenced by a small increase in the supernatants LDH levels. Taken together, our data show that P-I and P-III SVMPs presented comparable effects except for the hemorrhagic activity, suggesting that hydrolysis of coagulation factors or damage to endothelial cells are not sufficient for induction of local bleeding.
Assuntos
Bothrops/metabolismo , Venenos de Crotalídeos/química , Metaloendopeptidases/farmacologia , Metaloproteases/farmacologia , Sequência de Aminoácidos , Animais , Benchmarking , Fatores de Coagulação Sanguínea , Células Cultivadas , Venenos de Crotalídeos/farmacologia , Células Endoteliais/efeitos dos fármacos , Hemorragia/induzido quimicamente , Humanos , Metaloendopeptidases/química , Metaloproteases/química , Camundongos , Dados de Sequência Molecular , Veneno de Bothrops jararacaRESUMO
AIM: The aim of the present study was to compare the highest heart rate (HR) of soccer players recorded during competition matches with the maximum HR (HR(max)) estimated from age and the highest HR recorded in effort tests within a single category (intracategory) and between categories (intercategories). METHODS: The sample was made up of 19 under-17 athletes, 12 under-20 athletes and 14 professional athletes of a Brazilian first division soccer team. Players' HR was monitored during official competition matches and maximum effort test with a set of HR monitors. The highest HR recorded during competitive matches (MHR1) was considered as the highest HR value attained by each player during matches. HR(max) estimated from age (MHR2) was estimated by using the equation HR(max)= (220-age). The highest HR recorded in effort tests (MHR3) was determined as being the highest HR value recorded during a maximum effort test (1 000-m run). The Wilcoxon test was used in intracategory statistical analysis. The Kruskal Wallis test was used in intercategory statistical analysis. The significance level adopted was P<0.05. RESULTS: In all categories, MHR3 was lower than MHR1. Concerning intercategory analysis, the three categories did not exhibit a difference in MHR1 RESULTS: Relative to MHR3, the under-17 and under-20 categories were not different from each other. These two categories exhibited larger MHR3 values than the professional one did. CONCLUSION: HR(max) measured during field tests can be underestimated in relation to that measured during competition activities, maybe because the tests represent an artificial situation for athletes, who do not feel as motivated as during competitions.
Assuntos
Comportamento Competitivo/fisiologia , Frequência Cardíaca/fisiologia , Adolescente , Adulto , Brasil , Humanos , Masculino , Monitorização Ambulatorial/instrumentação , Consumo de Oxigênio/fisiologia , Esforço Físico/fisiologia , Futebol/fisiologiaRESUMO
Crystals of a myotoxic phospholipase A(2) from Bothrops neuwiedi pauloensis have been obtained. They diffracted at 2.5 A resolution using a synchrotron radiation source and belong to space group P3(1)21. Preliminary analysis shows that there are two molecules in the asymmetric unit.
Assuntos
Bothrops , Venenos de Crotalídeos/química , Neurotoxinas/química , Fosfolipases A/química , Animais , Brasil , Cristalização , Proteínas de Répteis , Difração de Raios XRESUMO
The use of plants as medicine has been referred to since ancient peoples, perhaps as early as Neanderthal man. Plants are a source of many biologically active products and nowadays they are of great interest to the pharmaceutical industry. The study of how people of different culture use plants in particular ways has led to the discovery of important new medicines. In this work, we verify the possible activity of Musa paradisiaca L. (Musaceae) against the toxicity of snake venoms. Musa paradisiaca, an important source of food in the world, has also been reported to be popularly used as an anti-venom. Interaction of Musa paradisiaca extract (MsE) with snake venom proteins has been examined in this study. Phospholipase A2 (PLA2), myotoxic and hemorrhagic activities, including lethality in mice, induced by crotalidae venoms were significantly inhibited when different amounts of MsE were mixed with these venoms before assays. On the other hand, mice that received MsE and venoms without previous mixture or by separated routes were not protected against venom toxicity. Partial chemical characterization of MsE showed the presence of polyphenols and tannins and they are known to non-specifically inactivate proteins. We suggest that these compounds can be responsible for the in vitro inhibition of the toxic effects of snake venoms. In conclusion, according to our results, using mice as experimental model, MsE does not show protection against the toxic effects of snake venoms in vivo, but if was very effective when the experiments were done in vitro.
Assuntos
Venenos de Crotalídeos/antagonistas & inibidores , Hemorragia/prevenção & controle , Musa/metabolismo , Músculo Esquelético/efeitos dos fármacos , Fosfolipases A/efeitos dos fármacos , Extratos Vegetais/farmacologia , Animais , Venenos de Crotalídeos/química , Venenos de Crotalídeos/toxicidade , Avaliação Pré-Clínica de Medicamentos/métodos , Flavonoides/química , Flavonoides/farmacologia , Frutas/química , Frutas/metabolismo , Hemorragia/induzido quimicamente , Masculino , Camundongos , Musa/química , Músculo Esquelético/patologia , Músculo Esquelético/ultraestrutura , Neurotoxinas/efeitos adversos , Neurotoxinas/antagonistas & inibidores , Neurotoxinas/química , Fenóis/química , Fenóis/farmacologia , Fosfolipases A/efeitos adversos , Fosfolipases A2 , Extratos Vegetais/química , Plantas Medicinais , Polifenóis , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Taninos/química , Taninos/farmacologiaRESUMO
The aqueous extract from the leaves of Casearia mariquitensis (C. m.), a plant found in Brazilian open pastures, was assayed for its ability to inhibit some hematological and hemostatic effects induced by neuwiedase, a 22 kDa class P-I metalloproteinase from the venom of the South American pit viper Bothrops neuwiedi pauloensis. The aqueous extract from C. m. was able to neutralize the hematological alterations induced by the crude venom (C.V.) upon erythrocytes when the venom was incubated at a ratio of 1:10 (w/w, venom/extract), but it did not neutralize the platelet decreasing ability of C.V. The plasma fibrinogen concentration decreased approximately 36% and 83% when 0.6 LD(50) of the C.V. or neuwiedase, respectively, were injected by i.p. route in mice, and the aqueous extract from C. m. was able to inhibit this effect. The Bbeta fibrinogen chain was protected against degradation caused by crude venom and neuwiedase when the venom or toxin were incubated with C. m. extract. We also observed that this extract exerted a very slight effect on the clotting time, prolonging it only to a little extent. The pulmonary hemorrhage induced by neuwiedase when injected intravenously with 0.6 LD(50) was completely inhibited when this toxin was incubated with the extract at a ratio of 1:10 (w/w, toxin/extract). It is concluded that C. m. displays components able to inhibit some hematological and systemic alterations induced by C.V.
Assuntos
Casearia/química , Inibidores Enzimáticos/farmacologia , Metaloendopeptidases/antagonistas & inibidores , Venenos de Víboras/antagonistas & inibidores , Animais , Coagulação Sanguínea/efeitos dos fármacos , Plaquetas/efeitos dos fármacos , Bothrops , Venenos de Crotalídeos/antagonistas & inibidores , Venenos de Crotalídeos/enzimologia , Eritrócitos/efeitos dos fármacos , Fibrinogênio/análise , Fibrinogênio/metabolismo , Fibrinólise/efeitos dos fármacos , Hematócrito , Metaloproteases/antagonistas & inibidores , Metaloproteases/metabolismo , Camundongos , Extratos Vegetais/farmacologia , Venenos de Víboras/enzimologiaRESUMO
The pathological alterations induced by neuwiedase, a 22 kDa class P-I metalloproteinase from the venom of the South American pit viper Bothrops neuwiedi, were studied in mice. Neuwiedase was devoid of hemorrhagic activity when tested in the skin up to a dose of 200 microgram, and also after intramuscular injection in the gastrocnemius. However, it induced bleeding when applied onto the mouse cremaster muscle in intravital microscopy experiments, and caused pulmonary hemorrhage when injected intravenously at doses higher than 5 microgram/g. Median lethal dose (LD(50)) by the intravenous route was 5 microgram/g, whereas LD(50) of crude venom was 0.47 microgram/g. After intramuscular injection, neuwiedase induced a mild myotoxic effect, evidenced histologically and by the increment in plasma creatine kinase activity, but it was devoid of hemorrhagic and thrombotic effects. In contrast, crude B. neuwiedi venom induced prominent hemorrhage and myonecrosis in gastrocnemius muscle. Both venom and neuwiedase induced an inflammatory reaction in muscle tissue characterized by abundant polymorphonuclear leukocytes. Moreover, a conspicuous edema developed in the foot pad after subcutaneous injection of neuwiedase. Anti-neuwiedase antibodies produced in rabbits were effective in the neutralization of hemorrhagic activity of crude venom, evidencing immunological cross-reactivity between neuwiedase and other hemorrhagic metalloproteinases present in the venom, and suggesting that metalloproteinases devoid of, or having low, hemorrhagic activity could be good immunogens to generate antibodies effective against high molecular mass metalloproteinasas having potent hemorrhagic activity. It is concluded that neuwiedase, despite its lack of hemorrhagic effect when injected in the gastrocnemius muscle, contributes to local tissue damage by inducing edema, inflammatory infiltrate and mild myotoxicity, and by degrading extracellular matrix components. In addition, large doses of neuwiedase may contribute to pulmonary bleeding
Assuntos
Bothrops , Venenos de Crotalídeos/enzimologia , Metaloendopeptidases/toxicidade , Venenos de Víboras/toxicidade , Animais , Anticorpos/imunologia , Anticorpos/farmacologia , Anticorpos/uso terapêutico , Creatina Quinase/metabolismo , Venenos de Crotalídeos/antagonistas & inibidores , Venenos de Crotalídeos/imunologia , Venenos de Crotalídeos/toxicidade , Edema/induzido quimicamente , Edema/tratamento farmacológico , Hemorragia/induzido quimicamente , Hemorragia/tratamento farmacológico , Técnicas In Vitro , Inflamação/induzido quimicamente , Inflamação/tratamento farmacológico , Dose Letal Mediana , Pulmão/efeitos dos fármacos , Pulmão/patologia , Masculino , Metaloendopeptidases/antagonistas & inibidores , Metaloendopeptidases/imunologia , Camundongos , Músculos/efeitos dos fármacos , Músculos/patologia , Testes de Neutralização , Fatores de Tempo , Venenos de Víboras/antagonistas & inibidores , Venenos de Víboras/imunologiaRESUMO
Venoms from eight Bothrops spp. were fractionated by ion-exchange chromatography on CM-Sepharose at pH 8.0 for the purification of myotoxins. Chromatographic profiles showed differences regarding myotoxic components among these venoms. B. alternatus, B. atrox and B. jararaca venoms did not show the major basic myotoxic fractions identified in the other venoms. Polyacrylamide gel electrophoresis for basic proteins also showed distinct patterns for these toxins. In vivo, all the isolated myotoxins induced release of creatine kinase due to necrosis of muscle fibers, accompanied by polymorphonuclear cell infiltration, and edema in the mouse paw. In addition, the toxins showed cytotoxic and liposome-disrupting activities in vitro. B. jararacussu bothropstoxins-I (BthTX-I) and II (BthTX-II) were submitted to chemical modifications of: His, by 4-bromophenacyl bromide (BPB) or photooxidation by Rose Bengal (RB); Tyr, by 2-nitrobenzenesulphonyl fluoride (NBSF); and Trp, by o-nitrophenylsulphenyl chloride (NPSC). The myotoxic and cytotoxic activities of BthTX-I, a Lys49 PLA(2) homologue, after modification by BPB, RB, NBSF and NPSC, were reduced to 50%, 20%, 75%, 65% and 13%, 0.5%, 76%, 58%, respectively. However, the edema-inducing and liposome-disrupting activities were not significantly reduced by the above modifications. BPB-treated BthTX-II, an Asp49 PLA(2) homologue, lost most of its catalytic, indirect hemolytic, anticoagulant, myotoxic and cytotoxic activities. The edema-inducing and liposome-disrupting activities were reduced to 50% and 80%, respectively. Lethality caused by BthTX-I and -II was strongly reduced after treatment with BPB or RB, but only partially with NBSF or NPSC. BthTX-I and -II, both native or modified, migrated similarly in a charge-shift electrophoresis. Antibodies raised against BthTX-I or -II, B. asper Basp-II and the C-terminal 115-129 peptide from Basp-II did not show significant differences in their cross-reactivity with the modified toxins, except with RB photooxidized toxins.
Assuntos
Venenos de Crotalídeos/toxicidade , Músculo Esquelético/efeitos dos fármacos , Fosfolipases A/toxicidade , Animais , Bothrops , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Cromatografia por Troca Iônica , Venenos de Crotalídeos/química , Venenos de Crotalídeos/isolamento & purificação , Edema/induzido quimicamente , Dose Letal Mediana , Lipossomos , Masculino , Camundongos , Músculo Esquelético/patologia , Necrose , Fosfolipases A/isolamento & purificaçãoRESUMO
Aqueous extract from Casearia sylvestris leaves, a typical plant from Brazilian open pastures, was able to neutralize the hemorrhagic activity caused by Bothrops asper, Bothrops jararacussu, Bothrops moojeni, Bothrops neuwiedi and Bothrops pirajai venoms. It also neutralized two hemorrhagic metalloproteinases from Bothrops asper venom. Proteolytic activity on casein induced by bothropic venoms and by isolated proteases, including Bn2 metalloproteinase from B. neuwiedi venom, was also inhibited by the C. sylvestris extract in different levels. The alpha-fibrinogen chain was partially protected against degradation caused by B. jararacussu venom, when this venom was incubated with C. sylvestris extract. We also observed that this extract partially increased the time of plasma coagulation caused by B. jararacussu, B. moojeni and B. neuwiedi venoms. C. sylvestris extract did not induce proteolysis in any substrate assayed.
Assuntos
Bothrops/fisiologia , Venenos de Crotalídeos/antagonistas & inibidores , Inibidores Enzimáticos/farmacologia , Metaloendopeptidases/antagonistas & inibidores , Extratos Vegetais/farmacologia , Animais , Caseínas/metabolismo , Venenos de Crotalídeos/enzimologia , Fibrinogênio/metabolismo , Fibrinólise/efeitos dos fármacos , Hemorragia/patologia , Hemorragia/prevenção & controle , Metaloendopeptidases/metabolismo , Dermatopatias/patologia , Dermatopatias/prevenção & controleRESUMO
Bothtrops moojeni snake venom was fractionated on a CM-Sepharose column which was previously equilibrated with 0.05 M ammonium bicarbonate buffer at pH 8.0 and subsequently eluted with an ammonium bicarbonate concentration gradient from 0.05 to 0.5 M at constant pH (8.0) and temperature (25 degrees C). The fraction which eluted last (M-VI) showed, after direct lyophilization, a single band by polyacrylamide gel electrophoresis (PAGE) and SDS-PAGE, indicating an approximate Mr of 14000 and 27000, in the presence and absence of dithiothreitol, respectively. Its amino acid composition revealed a high level of hydrophobic and basic amino acids as well as 14 half-cystine residues. Its isoelectric point and extinction coefficient (E(1.0 mg/ml) (1.0 cm) at 278 nm and pH 7.0) were 8.2 and 1.170, respectively. M-VI was devoid of phospholipase A2 (PLA2) activity on egg yolk, as well as of hemorrhagic, anticoagulant and coagulant activities, but could induce drastic necrosis on skeletal muscle fibres as well as rapid and transient edema on the rat paw. Its N-terminal sequence: SLFELGKMILQETGKNPAKSYGVYGCNCGVGGRGKPKDATDRCCYVHKCCYK... revealed high homology with other Lys 49 PLA2-like myotoxins from other bothropic venoms. Orthorhombic crystals of M-VI, which diffracted to a maximal resolution of 1.6 A, were obtained and indicated the presence of a dimer in the asymmetrical unit.
Assuntos
Bothrops/metabolismo , Venenos de Crotalídeos/química , Fosfolipases A/análise , Fosfolipases A/isolamento & purificação , Sequência de Aminoácidos , Animais , Edema/induzido quimicamente , Eletroforese em Gel de Poliacrilamida , Membro Posterior , Dados de Sequência Molecular , Peso Molecular , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/patologia , Miofibrilas/efeitos dos fármacos , Necrose , Fosfolipases A/química , Fosfolipases A/toxicidade , Fosfolipases A2 , Ratos , Difração de Raios XRESUMO
The crude aqueous extract from the leaves of Casearia sylvestris, a plant found in Brazilian open pastures, was assayed for its ability to inhibit phospholipase A2 (PLA2) activity and some biological activities of bee and several snake venoms, and of a number of isolated PLA2s. The extract induced partial inhibition of the PLA2 activity of venoms containing class I, II and III PLA2s. When tested against the purified toxins, it showed the highest efficacy against class II PLA2s from viperid venoms, being relatively ineffective against the class I PLA2 pseudexin. In addition, C. sylvestris extract significantly inhibited the myotoxic activity of four Bothrops crude venoms and nine purified myotoxic PLA2s, including Lys-49 and Asp-49 variants. The extract was able to inhibit the anticoagulant activity of several isolated PLA2s, with the exception of pseudexin. Moreover, it partially reduced the edema-inducing activity of B. moojeni and B. jararacussu venoms, as well as of myotoxins MjTX-II and BthTX-I. The extract also prolonged the survival time of mice injected with lethal doses of several snake venoms and neutralized the lethal effect induced by several purified PLA2 myotoxins. It is concluded that C. sylvestris constitutes a rich source of PLA2 inhibitors.
Assuntos
Antitoxinas/farmacologia , Venenos de Abelha/metabolismo , Fosfolipases A/antagonistas & inibidores , Fosfolipases A/metabolismo , Extratos Vegetais/farmacologia , Rosales/química , Venenos de Serpentes/metabolismo , Animais , Anticoagulantes/farmacologia , Venenos de Abelha/antagonistas & inibidores , Venenos de Crotalídeos/metabolismo , Relação Dose-Resposta a Droga , Edema/tratamento farmacológico , Eletroforese em Gel de Poliacrilamida , Masculino , Camundongos , Fosfolipases A2 , Venenos de Serpentes/antagonistas & inibidores , Fatores de TempoRESUMO
The aim of this study is to describe and analyze Epidemiological Surveillance activities (ES) developed in a Health Care Unit and to identify their adherence to recommended Health Surveillance (HS) strategies. A checklist with the activities recommended by the Ministry of Health was used to conduct interviews with health professionals involved in ES activities. The data obtained from these interviews showed that Epidemiological Surveillance activities are limited to the notification and control of infectious diseases, and the nurses' labor is characterized by bureaucratic tasks. This shows that further discussion about Health Surveillance strategies is necessary to find ways to better implement them in health services.
Assuntos
Métodos Epidemiológicos , Vigilância da População , Brasil , Enfermagem em Saúde Comunitária , Humanos , Saúde Pública , Inquéritos e QuestionáriosRESUMO
Snake venom metalloproteinases (SVMPs) participate in a number of important biological, physiological and pathophysiological processes and are primarily responsible for the local tissue damage characteristic of viperid snake envenomations. The use of medicinal plant extracts as antidotes against animal venoms is an old practice, especially against snake envenomations. Such plants are sources of many pharmacologically active compounds and have been shown to antagonize the effects of some venoms and toxins. The present study explores the activity of triacontyl p-coumarate (PCT), an active compound isolated from root bark of Bombacopsis glabra vegetal extract (Bg), against harmful effects of Bothropoides pauloensis snake venom and isolated toxins (SVMPs or phospholipase A(2)). Before inhibition assays, Bg or PCT was incubated with venom or toxins at ratios of 1:1 and 1:5 (w/w; venom or isolated toxins/PCT) for 30 min at 37°C. Treatment conditions were also assayed to simulate snakebite with PCT inoculated at either the same venom or toxin site. PCT neutralized fibrinogenolytic activity and plasmatic fibrinogen depletion induced by B. pauloensis venom or isolated toxin. PCT also efficiently inhibited the hemorrhagic (3MDH - minimum hemorrhagic dose injected i.d into mice) and myotoxic activities induced by Jararhagin, a metalloproteinase from B. jararaca at 1:5 ratio (toxin: inhibitor, w/w) when it was previously incubated with PCT and injected into mice or when PCT was administered after toxin injection. Docking simulations using data on a metalloproteinase (Neuwiedase) structure suggest that the binding between the protein and the inhibitor occurs mainly in the active site region causing blockade of the enzymatic reaction by displacement of catalytic water. Steric hindrance may also play a role in the mechanism since the PCT hydrophobic tail was found to interact with the loop associated with substrate anchorage. Thus, PCT may provide a alternative to complement ophidian envenomation treatments.
Assuntos
Ácidos Cumáricos/química , Ácidos Cumáricos/farmacologia , Metaloproteases/antagonistas & inibidores , Metaloproteases/metabolismo , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Venenos de Serpentes/enzimologia , AnimaisRESUMO
Gyroxin, a thrombin-like enzyme isolated from Crotalus durissus terrificus venom and capable of converting fibrinogen into fibrin, presents coagulant and neurotoxic activities. The aim of the present study was to evaluate such coagulant and toxic properties. Gyroxin was isolated using only two chromatographic steps - namely gel filtration (Sephadex G-75) and affinity (Benzamidine Sepharose 6B) - resulting in a sample of high purity, as evaluated by RP-HPLC C2/C18 and electrophoretic analysis that showed a molecular mass of 30 kDa. Gyroxin hydrolyzed specific chromogenic substrates, which caused it to be classified as a serine proteinase and thrombin-like enzyme. It was stable from pH 5.5 to 8.5 and inhibited by Mn²+, Cu²+, PMSF and benzamidine. Human plasma coagulation was more efficient at pH 6.0. An in vivo toxicity test showed that only behavioral alterations occurred, with no barrel rotation. Gyroxin was not able to block neuromuscular contraction in vitro, which suggests that its action, at the studied concentrations, has no effect on the peripheral nervous system.
Assuntos
Animais , Ratos , Venenos de Crotalídeos , Trombina/isolamento & purificação , Trombina/toxicidadeRESUMO
The damaging effects of neuwiedase, a non-hemorrhagic snake venom metalloproteinase from P-I class, on gastrocnemius muscle are studied herein. Following neuwiedase injection, ultrastructural alterations were detected early showing disarrangement of skeletal muscle fibers (characterized by discontinuity of Z lines), mitochondrial swelling, and disruption of plasma membrane and basal lamina. Degradation of skeletal muscle and the appearance of an amorphous substance, primarily composed of cellular debris, were noted after 24 hours. The presence of neuwiedase at the injection site (detected by immunocytochemistry) revealed highly specific labeling of myofibril components of damaged myocytes. In addition, proteolysis of muscle proteins assayed through myofibrils extracted from gastrocnemius muscle indicated that neuwiedase provoked degradation of myofibrils, especially myosin. These results suggest that skeletal muscle damage, induced by neuwiedase, is probably due to its proteolytic action on myofibrils, which are responsible for the maintenance of the cellular architecture.
Assuntos
Animais , Coelhos , Bothrops , Metaloproteases/isolamento & purificação , Músculo Esquelético/ultraestrutura , Venenos de Víboras , CoelhosRESUMO
A fibrino(geno)lytic nonhemorrhagic metalloprotease (neuwiedase) was purified from Bothrops neuwiedi snake venom by a single chromatographic step procedure on a CM-Sepharose column. Neuwiedase represented 4.5% (w/w) of the crude desiccated venom, with an approximate Mr of 20,000 and pI 5.9. As regards the amino acid composition, neuwiedase showed similarities with other metalloproteases, with high proportions of Asx, Glx, Leu, and Ser. Atomic absorption spectroscopy showed that one mole of Zn2+ and one mole of Ca2+ were present per mole of protein. The cDNA encoding neuwiedase was isolated by RT-PCR from venom gland RNA, using oligonucleotides based on the partially determined amino-acid sequences of this metalloprotease. The full sequence contained approximately 594 bp, which codified the 198 amino acid residues with an estimated molecular weight of 22,375. Comparison of the nucleotide and amino acid sequences of neuwiedase with those of other snake venom metalloproteases showed a high level of sequential similarity. Neuwiedase has two highly conserved characteristics sequences H142E143XXH146XXG149XXH152 and C164I165M166. The three-dimensional structure of neuwiedase was modeled based on the crystal structure of Crotalus adamanteus Adamalysin II. This model revealed that the zinc binding site region showed a high structural similarity with other metalloproteases. The proteolyitc specificity, using the Bbeta-chain of oxidized insulin as substrate, was shown to be directed to the Ala14-Leu15 and Tyr16-Leu17 peptide bonds which were preferentially hydrolyzed. Neuwiedase is a Aalpha,Bbeta fibrinogenase. Its activity upon the Aalpha chain of fibrinogen was detected within 15 min of incubation. The optimal temperature and pH for the degradation of both Aalpha and Bbeta chains were 37 degrees C and 7.4-8.0, respectively. This activity was inhibited by EDTA and 1,10-phenantroline. Neuwiedase also showed proteolytic activity upon fibrin and some components of the extracellular matrix. However, it did not show TAME esterase activity and was not able to inhibit platelet aggregation.
Assuntos
Bothrops/metabolismo , Venenos de Crotalídeos/enzimologia , Metaloendopeptidases/química , Metaloendopeptidases/metabolismo , Venenos de Víboras/química , Venenos de Víboras/metabolismo , Sequência de Aminoácidos , Aminoácidos/análise , Animais , Sequência de Bases , Bothrops/genética , Venenos de Crotalídeos/genética , Venenos de Crotalídeos/toxicidade , DNA Complementar/genética , Fibrinólise/efeitos dos fármacos , Técnicas In Vitro , Ponto Isoelétrico , Metaloendopeptidases/genética , Modelos Moleculares , Dados de Sequência Molecular , Peso Molecular , Agregação Plaquetária/efeitos dos fármacos , Conformação Proteica , Coelhos , Homologia de Sequência de Aminoácidos , Venenos de Víboras/genéticaRESUMO
The antibothropic complex (ABC) from opossum (species Didelphis albiventris) serum was purified by chromatography on DEAE-Sephacel. It showed an acidic character and two polypeptide chains of ca. 45 kDa and 48 kDa, respectively. Lyophilized opossum serum or the ABC (100 micrograms), as well as ethylenediamine tetraacetate (0.25 mumoles) were able to completely neutralise the hemorrhagic effect of 50 micrograms of the desiccated venoms of Bothrops moojeni, Bothrops pirajai and Bothrops jararacussu. The myotoxic (100 micrograms venom in mice) and edematogenic (90 micrograms venom in rats) activities of Bothrops moojeni and Bothrops jararacussu venoms, as well as of the major myonecrotic protein (myotoxin-I) isolated from Bothrops moojeni venom, were also totally inhibited by the ABC (200 micrograms and 270 micrograms, respectively). The lyophilized opossum serum (30 micrograms) and the ABC (30 micrograms) reduced to 50% the phospholipase A2 activity of Bothrops moojeni venom (10 micrograms). The clotting activity of Bothrops alternatus and Bothrops moojeni (20 micrograms) on bovine plasma was also significantly inhibited by the ABC (60 micrograms).
Assuntos
Antivenenos/sangue , Antivenenos/farmacologia , Venenos de Crotalídeos/antagonistas & inibidores , Fosfolipases A/antagonistas & inibidores , Inibidores de Proteases/farmacologia , Animais , Bioensaio , Testes de Coagulação Sanguínea , Bothrops , Venenos de Crotalídeos/enzimologia , Edema/induzido quimicamente , Edema/prevenção & controle , Hemorragia/induzido quimicamente , Hemorragia/prevenção & controle , Masculino , Camundongos , Gambás/sangue , Fosfolipases A2 , Ratos , Ratos WistarRESUMO
The isolation and partial characterization of a serine protease with arginine ester hydrolase activity from Bothrops jararacussu snake venom are described. The purification procedure consisted of a gel filtration of the crude venom on Sephadex G-75 followed by an ion-exchange chromatography of the active fraction on DEAE-cellulose and a rechromatography on Bio-Rex 70 resin. The esterase fraction (DI-III), M(r) = 25,000 by SDS-PAGE, showed proteolytic activity on fibrinogen and casein. After 2 hr incubation, the A alpha and B beta chains of fibrinogen were intensely hydrolysed, while the gamma chain kept apparently intact, even after 20 hr of incubation. In spite of that, DI-III did not clot fibrinogen. DI-III induced edema in the rat paw. Although unable to release bradykinin, it induced contractions of the isolated rat uterus. DI-III did not catalyse the hydrolysis of bradykinin. Its arginine ester hydrolase activity was completely inhibited by diisopropyl fluorophosphate after 1 hr incubation, but not by phenylmethylsulfonyl fluoride under the same conditions.