RESUMO
The scorpion Centruroides limpidus limpidus (C.l.l.) is endemic in México, producing hundreds of accidents in humans; children being one of the most susceptible targets. Few studies reported that severe envenoming by scorpion venom induces cardiac damage and electrolytes abnormalities in children, but the relationship of envenoming severity and toxic blood levels is unknown. The aim of this study was to determine the relationship among clinical status of envenoming, serum electrolyte, electrocardiographic abnormalities, and serum toxin levels in 44 children stung by scorpion over a period of 6 months in the State of Morelos, Mexico. The patients were said to be asymptomatic, when they presented just local symptoms, and were said to be symptomatic when showing local symptoms and at least one systemic symptom. The clinical status was evaluated at the admission at the emergency room of the Hospital, and 30 min after the administration of polyspecific F(ab')2 anti-scorpion therapy to symptomatic children. Forty-one percent of the children were asymptomatic and 59% symptomatic. Potassium and sodium imbalance and an elongation of the QT interval were detected; the rate of hypokalemia was higher in symptomatic than on asymptomatic children (50% and 6%, respectively). Hypokalemia persisted in 19% in symptomatic patients, whereas sodium reached normal levels 30 min after anti-venom therapy. The hypokalemia statistically correlated with elongation of the QT interval. The concentration of the toxic components of C.l.l in serum was significantly higher in symptomatic than asymptomatic children, and the serum levels of the toxic component significantly decreased to undetectable levels after the application of anti-venom therapy. Despite the small size of the sample, this study establishes that severity of envenoming was statistically related to potassium imbalance in serum, QT interval and the concentration of toxic components in serum, which decreased at undetectable levels after specific treatment with the anti-scorpion venom, correlating with clinical disappearance or greatly reduction of symptoms of envenomation.
Assuntos
Mordeduras e Picadas , Eletrólitos/metabolismo , Venenos de Escorpião/metabolismo , Escorpiões , Adolescente , Animais , Criança , Eletrocardiografia , Feminino , Humanos , Lactente , Masculino , MéxicoRESUMO
BACKGROUND: Patients with systemic lupus erythematosus (SLE) have a higher risk for cardiovascular disease (CVD), not fully explained by the conventional risk factors. These patients have endothelial dysfunction (ED) as an early process of atherosclerosis, which can be reversed with therapy. OBJECTIVE: To determine the effect of ezetimibe plus pravastatin on endothelial function in patients with SLE after 12 months of treatment. PATIENTS AND METHODS: An open study, before and after, which assessed the effect of ezetimibe plus pravastatin treatment, was performed. Twenty two patients (21 women and one man) with diagnosis of SLE were studied, with a mean age 40 ± 5 years. Endothelial dysfunction was evaluated using vascular ultrasound of the brachial artery in order to measure the flow-mediated vasodilation (FMV) basal and after 12 months of treatment with pravastatin 40 mg/day plus ezetimibe 10 mg/day. In addition, a lipid profile: total cholesterol (TC), HDL-cholesterol (HDL-C), LDL-cholesterol (LDL-C), and serum C-reactive protein (CRP), was done. RESULTS: We found a basal FMV of 7.58% and 18.22% after 12 months of treatment, with an improvement of 10.64 points 95% CI (7.58-13.58), p < 0.001. TC decreased from 201.3 ± 58.9 mg/dL to 158.06 ± 50.13 mg/dL (p < 0.01); LDL-C from 125.78 ± 44.4 mg/dL to 78.8 ± 32.9 mg/dL (p < 0.001); HDL-C increased from 49.0 ± 16.8 mg/dL to 52.2 ± 13.8 mg/dL (p = 0.077). The basal and final concentrations of CRP were 4.49 and 2.8, respectively, with a mean decrease of 2.11 mg/dL, 95% CI (0.908-3.32), p < 0.002. Both drugs were well tolerated. CONCLUSION: Ezetimibe plus pravastatin significantly improved FMV in patients with SLE, decreasing ED and the lipid profile. This treatment ameliorated an early process of atherosclerosis and a risk factor for CVD.
Assuntos
Anticolesterolemiantes/administração & dosagem , Endotélio Vascular/efeitos dos fármacos , Ezetimiba/administração & dosagem , Lúpus Eritematoso Sistêmico/complicações , Pravastatina/administração & dosagem , Adulto , Anticolesterolemiantes/efeitos adversos , Aterosclerose/prevenção & controle , Artéria Braquial/diagnóstico por imagem , Proteína C-Reativa/análise , Colesterol/sangue , Quimioterapia Combinada , Endotélio Vascular/fisiopatologia , Ezetimiba/efeitos adversos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Pravastatina/efeitos adversos , Ultrassonografia , VasodilataçãoRESUMO
We studied the interethnic variation of the MMP-9 microsatellite in the Mestizo and Amerindian populations using blood samples collected from 435 healthy unrelated individuals from the Central Valley of Mexico. DNA samples were genotyped using the -90 (CA)12-27 repeat near the MMP transcriptional start site using capillary electrophoresis. Our data were compared with those from African, Asian, and European populations (N = 729). Both Mestizo and Amerindian populations were in Hardy-Weinberg equilibrium (P ≥ 0.05). However, strong genetic heterogeneity was found within the Mestizo population (94%, P ≤ 0.0001), which exhibited the highest frequency of Amerindian, African, and European alleles. Likewise, Amerindians showed 6.7% variation among populations (P ≤ 0.0001), suggesting a genetic substructure potentially associated with linguistic affiliations. These findings were corroborated with principal component and population differentiation analyses, which showed relative proximity among the Mestizos and their historical parental populations: Asian (FST ≥ 0.05), European (FST ≥ 0.09), and African (FST ≥ 0.02). Nevertheless, important differences were found between Mestizo and Nahuas (P ≤ 0.0001), and between Mestizo and Me'Phaas (P ≤ 0.0001). These findings highlight the importance of determining local-specific patterns to establish the population variability of MMP-9 and other polymorphic markers. Validation of candidate markers is critical to identifying risk factors; however, this depends on knowledge of population genetic variation, which increases the possibility of finding true causative variants. We also show that dissimilar ethnic backgrounds might lead to spurious associations. Our study provides useful considerations for greater accuracy and robustness in future genetic association studies.
Assuntos
População Negra/genética , Variação Genética , Indígenas Norte-Americanos/genética , Metaloproteinase 9 da Matriz/genética , Repetições de Microssatélites/genética , População Branca/genética , Alelos , Análise de Variância , Frequência do Gene , Genética Populacional/métodos , Genótipo , Geografia , Humanos , Desequilíbrio de Ligação , México , Análise de Componente Principal , Análise de Sequência de DNARESUMO
Humans may be exposed to arsenic (As) and fluoride (F) through water consumption. However, the interaction between these two elements and gene expression in apoptosis or inflammatory processes in children has not been thoroughly investigated. Herein, the expression of cIAP-1, XIAP, TNF-α, ENA-78, survivin, CD25, and CD40 was evaluated by RT-PCR. Additionally, the surface expression of CD25, CD40, and CD40L on peripheral blood mononuclear cells was analyzed by flow cytometry, and TNF-α was measured by Western blotting. This study examined 72 children aged 6-12 years who were chronically exposed to As (154.2µg/L) and F (5.3mg/L) in drinking water and in food cooked with the same water. The urine concentrations of As (6.9-122.4µg/L) were positively correlated with the urine concentrations of F (1.0-8.8mg/L) (r(2)=0.413, p<0.0001). The CD25 gene expression levels and urine concentrations of As and F were negatively correlated, though the CD40 expression levels were negatively correlated only with the As concentration. Age and height influenced the expression of cIAP-1, whereas XIAP expression was correlated only with age. Additionally, there was a lower percentage of CD25- and CD40-positive cells in the group of 6- to 8-year-old children exposed to the highest concentrations of both As and F when compared to the 9- to 12-year-old group (CD25: 0.7±0.8 vs. 1.1±0.9, p<0.0014; CD40: 16.0±7.0 vs. 21.8±5.8, p<0.0003). PHA-stimulated lymphocytes did not show any changes in the induction of CD25, CD69, or CD95. In summary, high concentrations of As and F alter the expression patterns of CD25 and CD40 at both the genetic and protein levels. These changes could decrease immune responses in children exposed to As and F.
Assuntos
Apoptose/efeitos dos fármacos , Arsênio/toxicidade , Exposição Ambiental , Fluoretos/toxicidade , Expressão Gênica/efeitos dos fármacos , Imunidade Ativa/efeitos dos fármacos , Leucócitos Mononucleares/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Apoptose/genética , Proteínas Reguladoras de Apoptose/genética , Proteínas Reguladoras de Apoptose/metabolismo , Arsênio/urina , Criança , Feminino , Fluoretos/urina , Humanos , Inflamação/genética , Inflamação/metabolismo , Leucócitos Mononucleares/metabolismo , Ativação Linfocitária/efeitos dos fármacos , Masculino , Fator de Necrose Tumoral alfa/genética , Fator de Necrose Tumoral alfa/metabolismo , Poluentes Químicos da Água/urinaRESUMO
A three-dimensional model of the alphaX I-domain of the horse integrin CD11c from dendritic cells provided information for selecting two segments of the primary structure for peptide synthesis. Peptide 1 contains 20 amino acids and peptide 2 has 17 amino acid residues. The first spans from position Thr229 to Arg248 of an alpha-helix segment of the structure, whereas peptide 2 goes from Asp158 to Phe174 and corresponds to an exposed segment of the loop considered to be the metal ion-dependent adhesion site. Murine polyclonal antisera against both peptides were generated and assayed in peripheral blood cell suspensions and in cryosections of horse lymph nodes. Only the serum against peptide 2 was capable of identifying cells in suspension and in situ by immunohistochemistry, some with evident dendritic morphology. Using this approach, an immunogenic epitope exposed in CD11c was identified in cells from horse lymph node in situ.
Assuntos
Antígeno CD11c/imunologia , Células Dendríticas/imunologia , Cavalos/imunologia , Sequência de Aminoácidos , Animais , Formação de Anticorpos , Antígeno CD11c/química , Antígeno CD11c/genética , Reações Cruzadas , Epitopos/química , Epitopos/genética , Feminino , Cavalos/genética , Humanos , Imuno-Histoquímica , Linfonodos/citologia , Linfonodos/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Modelos Moleculares , Dados de Sequência Molecular , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/genética , Fragmentos de Peptídeos/imunologia , Engenharia de Proteínas , Dobramento de Proteína , Estrutura Terciária de Proteína , Homologia de Sequência de AminoácidosRESUMO
The elevated expression of stress proteins is considered to be a universal response to adverse conditions, representing a potential mechanism of cellular defense against disease and a potential target for novel therapeutics. Exposure to arsenicals either in vitro or in vivo in a variety of model systems has been shown to cause the induction of a number of the major stress protein families such as heat shock proteins (Hsp). Among them are members with low molecular weight, such as metallotionein and ubiquitin, as well as ones with masses of 27, 32, 60, 70, 90, and 110 kDa. In most of the cases, the induction of stress proteins depends on the capacity of the arsenical to reach the target, its valence, and the type of exposure, arsenite being the biggest inducer of most Hsp in several organs and systems. Hsp induction is a rapid dose-dependent response (1-8 h) to the acute exposure to arsenite. Thus, the stress response appears to be useful to monitor the sublethal toxicity resulting from a single exposure to arsenite. The present paper offers a critical review of the capacity of arsenicals to modulate the expression and/or accumulation of stress proteins. The physiological consequences of the arsenic-induced stress and its usefulness in monitoring effects resulting from arsenic exposure in humans and other organisms are discussed.
Assuntos
Arsênio/toxicidade , Proteínas de Choque Térmico/biossíntese , Animais , Arsênio/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Proteínas de Choque Térmico HSP70/biossíntese , Proteínas de Choque Térmico HSP70/fisiologia , Proteínas de Choque Térmico/genética , Proteínas de Choque Térmico/fisiologia , Heme Oxigenase (Desciclizante)/biossíntese , Heme Oxigenase (Desciclizante)/fisiologia , Humanos , Proteínas de Membrana/biossíntese , Proteínas de Membrana/fisiologia , Metalotioneína/biossíntese , Metalotioneína/fisiologia , Estresse Oxidativo , Ubiquitina/biossínteseRESUMO
The Na+-channel-affecting toxin Cn2 represents the major and one of the most toxic components of the venom of the Mexican scorpion Centruroides noxius Hoffmann. A monoclonal antibody BCF2 raised against Cn2 has been shown previously to be able to neutralize the toxic effect of Cn2 and of the whole venom of C. noxius. In the present study the epitope was mapped to a surface region comprising the N- and C-terminal segments of Cn2, using continuous and discontinuous synthetic peptides, designed on the basis of the sequence and a three-dimensional model of Cn2. The study of peptides of varying length resulted in the identification of segments 5-14 and 56-65 containing residues essential for recognition by BCF2. The peptide (abbreviated SP7) with the highest affinity to BCF2 (IC50 = 5.1 microM) was a synthetic heterodimer comprising the amino acid sequence from position 3-15 (amidated) of Cn2, bridged by disulfide to peptide from position 54-66, acetylated and amidated. Similar affinity was found with peptide SP1 [heterodimer comprising residues 1-14 (amidated) of Cn2, bridged with synthetic peptide 52-66 (acetylated)]. SP1 and SP7 were used to induce anti-peptide antibodies in mouse and rabbit. Both peptides were highly immunogenic. The sera obtained were able to recognize Cn2 and to neutralize Cn2 in vitro. The most efficient protection (8.3 microgram Cn2 neutralized per mL of serum) was induced by rabbit anti-SP1 serum.
Assuntos
Venenos de Escorpião/imunologia , Escorpiões/imunologia , Sequência de Aminoácidos , Animais , Anticorpos Monoclonais , Mapeamento de Epitopos , Feminino , Humanos , Imunização , Técnicas In Vitro , Dose Letal Mediana , Camundongos , Modelos Moleculares , Dados de Sequência Molecular , Testes de Neutralização , Fragmentos de Peptídeos/genética , Fragmentos de Peptídeos/imunologia , Conformação Proteica , Coelhos , Venenos de Escorpião/genética , Venenos de Escorpião/toxicidade , Escorpiões/genética , Escorpiões/patogenicidade , Canais de Sódio/efeitos dos fármacosRESUMO
Envenomations after scorpion stings are a major health problem throughout the world. Their specific treatment is immunotherapy which consists of the injection of specific antibody. In this article, we studied the pharmacokinetics of the toxic fraction of Centruroides limpidus limpidus venom (fraction II) in experimentally envenomed rabbits. After an intravenous injection, fraction II (FII) was rapidly distributed and eliminated from the body (terminal half-life of 1.9 h). When injected subcutaneously, high concentrations of FII were measured in the vascular space rapidly after the injection (Tmax = 1 h) and FII was eliminated with a terminal half-life of 1.8 h, close to that determined after intravenous injection. These observations go along with the rapid onset of clinical symptoms observed after accidental envenomations. To investigate the mechanism of action of antivenom, we examined the effects of the intravenous administration of antivenom (horse F(ab')2 directed against Centruroides venoms) on the pharmacokinetics of FII. Immunotherapy performed 2 h after the experimental envenomation largely increased the area under the concentration time curve of FII compared to that calculated in absence of immunotherapy (13,000 versus 170 ng h ml(-1), respectively). These observations agree with previous findings which showed that specific antibody fragments are able to remove drugs from their site of action and sequester them in the vascular space. These studies provide a powerful tool to determine an excellent procedure for further improvement of immunotherapy.
Assuntos
Antivenenos/uso terapêutico , Fragmentos Fab das Imunoglobulinas/uso terapêutico , Imunoterapia , Picadas de Escorpião/metabolismo , Venenos de Escorpião/farmacocinética , Animais , Área Sob a Curva , Western Blotting , Eletroforese em Gel de Poliacrilamida , Meia-Vida , Coelhos , Picadas de Escorpião/terapia , Venenos de Escorpião/imunologia , Escorpiões/imunologia , Distribuição TecidualRESUMO
Seven toxic peptides from the venom of Tityus bahiensis and Tityus stigmurus was isolated and sequenced, five of them to completion. The most abundant peptide from each of these two species of scorpion was 95% identical with that of toxin gamma from the venom of Tityus serrulatus. They were consequently named gamma-b and gamma-st respectively. The genes encoding these new gamma-like peptides were cloned and sequenced by utilizing oligonucleotides synthesized according to known cDNA sequences of toxin gamma, and amplified by PCR on templates of DNA purified from both T. bahiensis and T. stigmurus. They contain an intron of approx. 470 bp. Possible mechanisms of processing and expressing these peptides are discussed, in view of the fact that glycine is the first residue of the N-terminal sequence of T. stigmurus, whereas lysine is the residue at position 1 of toxin gamma from T. serrulatus and T. bahiensis. In addition, chemical characterization of the less abundant toxic peptides showed the presence of at least four distinct families of peptides in all three species of the genus Tityus studied. There is a large degree of similarity among peptides from different venoms of the same family. By using specific horse and rabbit antisera, the venoms of T. bahiensis, T. serrulatus and T. stigmurus were compared. They showed an extended degree of cross-reactivity. Thus these three species of scorpion have similar toxic components, the genes of which are similarly organized, processed and expressed.
Assuntos
Genes , Peptídeos/química , Peptídeos/genética , Venenos de Escorpião/química , Venenos de Escorpião/genética , Escorpiões/genética , Sequência de Aminoácidos , Animais , Anticorpos , Sequência de Bases , Clonagem Molecular , DNA Complementar/genética , Imunoquímica , Camundongos , Dados de Sequência Molecular , Coelhos , Venenos de Escorpião/imunologia , Homologia de Sequência de Aminoácidos , Especificidade da EspécieRESUMO
Seven peptides corresponding to the amino acid sequence of toxin 2 from the scorpion Centruroides noxius were chemically synthesized, purified and assayed in mice for their putative neutralizing properties against scorpion toxins. All the peptides were immunogenic and some produced neutralizing antibodies, as verified by injecting the antisera with toxin into naive animals. However, direct challenge of pre-immunized mice (with the longest synthetic peptides of 27 and 57 amino acid residues) revealed an unexpected sensitization phenomena: the animals did not resist injection of one LD50 of purified toxin 2 (5% survival), but pre-immunization of mice with native toxin protected 100% of the animals. These findings suggest that vaccine preparations with synthetic peptides corresponding to the amino acid sequence of certain toxins should be analyzed cautiously.