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1.
J Dairy Sci ; 107(7): 4704-4713, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38310964

RESUMEN

The large-scale recording of traits such as feed efficiency (FE) and methane emissions (ME) for use in genetic improvement programs is complex, costly, and time-consuming. Therefore, heritable traits that can be continuously recorded in dairy herds and are correlated with FE and ME traits could provide useful information for genetic evaluation. Rumination time has been suggested to be associated with FE, methane production (MeP; ME in g/d), and production traits at the phenotypic level. Therefore, the objective of this study was to investigate the genetic relationships among rumination time (RT), FE, methane and production traits using 7,358 records from 656 first-lactation Holstein cows. The estimated heritabilities were moderate for RT (0.45 ± 0.14), MeP (0.36 ± 0.12), milk yield (0.40 ± 0.08), fat yield (0.29 ± 0.06), protein yield (0.32 ± 0.07), and energy-corrected milk (0.28 ± 0.07), but were low and nonsignificant for FE (0.15 ± 0.07), which was defined as the residual of the multiple linear regression of DMI on energy-corrected milk and metabolic body weight. A favorable negative genetic correlation was estimated between RT and MeP (-0.53 ± 0.24), whereas a positive favorable correlation was estimated between RT and energy-corrected milk (0.49 ± 0.11). The estimated genetic correlation of RT with FE (-0.01 ± 0.17) was not significantly different from zero but showed a trend of a low correlation with dry matter intake (0.21 ± 0.13). These results indicate that RT is genetically associated with MeP and milk production traits, but high standard errors indicate that further analyses should be conducted to verify these findings when more data for RT, MeP, and FE become available.


Asunto(s)
Lactancia , Metano , Leche , Animales , Bovinos/genética , Metano/biosíntesis , Metano/metabolismo , Femenino , Lactancia/genética , Leche/metabolismo , Leche/química , Alimentación Animal , Fenotipo , Dieta/veterinaria
2.
Arch Biochem Biophys ; 731: 109424, 2022 11 30.
Artículo en Inglés | MEDLINE | ID: mdl-36220378

RESUMEN

As in most enveloped RNA viruses, the Respiratory Syncytial Virus Matrix (RSV-M) protein plays key roles in viral assembly and uncoating. It also plays non-structural roles related to transcription modulation through nucleo-cytoplasmic shuttling and nucleic acid binding ability. We dissected the structural and conformational changes underlying the switch between multiple functionalities, identifying Ca2+ binding as a key factor. To this end, we tackled the analysis of M's conformational stability and equilibria. While in silico calculations predict two potential calcium binding sites per protomer, purified RSV-M dimer contains only one strongly bound calcium ion per protomer. Incubation of RSV-M in the presence of excess Ca2+ leads to an increase in the thermal stability, confirming additional Ca2+ binding sites. Moreover, mild denaturant concentrations trigger the formation of higher order oligomers which are otherwise prevented under Ca2+ saturation conditions, in line with the stabilizing effect of the additional low affinity binding site. On the other hand, Ca2+ removal by chelation at pH 7.0 causes a substantial decrease in the thermal stability leading to the formation of amorphous, spherical-like aggregates, as assessed by TEM. Even though the Ca2+ content modulates RSV-M oligomerization propensity, it does affect its weak RNA binding ability. RSV-M undergoes a substantial conformational change at pHs 4.0 to 5.0 that results in the exposure of hydrophobic surfaces, an increase beta sheet content but burial of tryptophan residues. While low ionic strength promotes dimer dissociation at pH 4.0, physiological concentrations of NaCl lead to the formation of soluble oligomers smaller than 400 kDa at pH 4.0 or insoluble aggregates with tubular morphology at pH 5.0, supporting a fine tuning by pH. Furthermore, the dissociation constants estimated for the low- and high affinity calcium binding sites are 13 µM and 58 nM, respectively, suggesting an intracellular calcium sensing mechanism of RSV-M upon infection. We uncover a finely tuned interplay between calcium binding, ionic strength, and pH changes compatible with the different cellular compartments where M plays key roles, revealing diverse conformational equilibria, oligomerization, and high order structures, required to stabilize the virion particle by a layer of molecules positioned between the membrane and the nucleocapsid.


Asunto(s)
Calcio , Virus Sincitial Respiratorio Humano , Subunidades de Proteína , Virus Sincitial Respiratorio Humano/química , Ensamble de Virus , Concentración Osmolar , Unión Proteica
3.
Proc Biol Sci ; 287(1923): 20192922, 2020 03 25.
Artículo en Inglés | MEDLINE | ID: mdl-32183629

RESUMEN

The role of cognitive factors in triggering the stress response is well established in humans and mammals (aka cognitive appraisal theory) but very seldom studied in other vertebrate taxa. Predictability is a key factor of the cognitive evaluation of stimuli. In this study, we tested the effects of stressor predictability on behavioral, physiological and neuromolecular responses in the European sea bass (Dicentrarchus labrax). Groups of four fish were exposed to a predictable (signalled) or unpredictable (unsignalled) stressor. Stressor predictability elicited a lower behavioural response and reduced cortisol levels. Using the expression of immediate early genes (c-fos, egr-1, bdnf and npas4) as markers of neuronal activity, we monitored the activity of three sea bass brain regions known to be implicated in stressor appraisal: the dorsomedian telencephalon, Dm (putative homologue of the pallial amygdala); and the dorsal (Dld) and ventral (Dlv) subareas of the dorsolateral telencephalon (putative homologue of the hippocampus). The activity of both the Dm and Dlv significantly responded to stressor predictability, suggesting an evolutionarily conserved role of these two brain regions in information processing related to stressor appraisal. These results indicate that stressor predictability plays a key role in the activation of the stress response in a teleost fish, hence highlighting the role of cognitive processes in fish stress.


Asunto(s)
Lubina/fisiología , Estrés Fisiológico/fisiología , Animales , Cognición/fisiología , Estrés Psicológico
4.
Arch Biochem Biophys ; 671: 77-86, 2019 08 15.
Artículo en Inglés | MEDLINE | ID: mdl-31229488

RESUMEN

Virus from the Mononegavirales order share common features ranging from virion structure arrangement to mechanisms of replication and transcription. One of them is the way the nucleoprotein (N) wraps and protects the RNA genome from degradation by forming a highly ordered helical nucleocapsid. However, crystal structures from numerous Mononegavirales reveal that binding to the nucleoprotein results in occluded nucleotides that hinder base pairing necessary for transcription and replication. This hints at the existence of alternative conformations of the N protein that would impact on the protein-RNA interface, allowing for transient exposure of the nucleotides without complete RNA release. Moreover, the regulation between the alternative conformations should be finely tuned. Recombinant expression of N from the respiratory syncytial virus form regular N/RNA common among all Mononegavirales, and these constitute an ideal minimal unit for investigating the mechanisms through which these structures protect RNA so efficiently while allowing for partial accessibility during transcription and replication. Neither pH nor high ionic strength could dissociate the RNA but led to irreversible aggregation of the nucleoprotein. Low concentrations of guanidine chloride dissociated the RNA moiety but leading to irreversible aggregation of the protein moiety. On the other hand, high concentrations of urea and long incubation periods were required to remove bound RNA. Both denaturants eventually led to unfolding but converged in the formation of an RNA-free ß-enriched intermediate species that remained decameric even at high denaturant concentrations. Although the N-RNA rings interact with the phosphoprotein P, the scaffold of the RNA polymerase complex, this interaction did not lead to RNA dissociation from the rings in vitro. Thus, we have uncovered complex equilibria involving changes in secondary structure of N and RNA loosening, processes that must take place in the context of RNA transcription and replication, whose detailed mechanisms and cellular and viral participants need to be established.


Asunto(s)
Proteínas de la Nucleocápside/metabolismo , ARN Viral/metabolismo , Concentración de Iones de Hidrógeno , Simulación de Dinámica Molecular , Conformación de Ácido Nucleico , Proteínas de la Nucleocápside/química , Concentración Osmolar , Unión Proteica , Estructura Secundaria de Proteína , Estabilidad del ARN , ARN Viral/química , Virus Sincitial Respiratorio Humano/química , Temperatura , Termodinámica
5.
Genetica ; 143(5): 613-31, 2015 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-26280323

RESUMEN

The objective of this study was to evaluate information on minisatellite and microsatellite markers in papaya (Carica papaya L.). Forty minisatellites and 91 microsatellites were used for genotyping 24 papaya accessions. Estimates of genetic diversity, genetic linkage and analyses of population structure were compared. A lower average number of alleles per locus was observed in minisatellites (3.10) compared with microsatellites (3.57), although the minisatellites showed rarer alleles (18.54 %) compared with microsatellite (13.85 %). Greater expected (He = 0.52) and observed (Ho = 0.16) heterozygosity was observed in the microsatellites compared with minisatellites (He = 0.42 and Ho = 0.11), possibly due to the high number of hermaphroditic accessions, resulting in high rates of self-fertilization. The polymorphic information content and Shannon-Wiener diversity were also higher for microsatellites (from 0.47 to 1.10, respectively) compared with minisatellite (0.38 and 0.85, respectively). The probability of paternity exclusion was high for both markers (>0.999), and the combined probability of identity was from 1.65(-13) to 4.33(-38) for mini- and micro-satellites, respectively, which indicates that both types of markers are ideal for genetic analysis. The Bayesian analysis indicated the formation of two groups (K = 2) for both markers, although the minisatellites indicated a substructure (K = 4). A greater number of accessions with a low probability of assignment to specific groups were observed for microsatellites. Collectively, the results indicated higher informativeness of microsatellites. However, the lower informative power of minisatellites may be offset by the use of larger number of loci. Furthermore, minisatellites are subject to less error in genotyping because there is greater power to detect genotyping systems when larger motifs are used.


Asunto(s)
Carica/genética , Repeticiones de Microsatélite , Repeticiones de Minisatélite , Alelos , Teorema de Bayes , Ligamiento Genético , Variación Genética , Genética de Población , Técnicas de Genotipaje , Polimorfismo Genético
6.
Genet Mol Res ; 13(3): 6472-85, 2014 Aug 25.
Artículo en Inglés | MEDLINE | ID: mdl-25158266

RESUMEN

Single nucleotide polymorphism (SNP) markers were used in the largest cassava (Manihot esculenta Crantz) germplasm collection from Brazil to develop core collections based on the maximization strategy. Subsets with 61, 64, 84, 128, 256, and 384 cassava accessions were selected and named PoHEU, MST64, PoRAN, MST128, MST256, and MST384, respectively. All the 798 alleles identified by 402 SNP markers in the entire collection were captured in all core collections. Only small alterations in the diversity parameters were observed for the different core collections compared with the complete collection. Because of the optimal adjustment of the validation parameters representative of the complete collection, the absence of genotypes with high genetic similarity and the maximization of the genetic distances between accessions of the PoHEU core collection, which contained 4.7% of the accessions of the complete collection, maximized the genetic conservation of this important cassava collection. Furthermore, the development of this core collection will allow concentrated efforts toward future characterization and agronomic evaluation of accessions to maximize the diversity and genetic gains in cassava breeding programs.


Asunto(s)
Genotipo , Manihot/genética , Repeticiones de Microsatélite , Polimorfismo de Nucleótido Simple , Alelos , Brasil , Cruzamiento , Marcadores Genéticos , Variación Genética , Dispersión de las Plantas , Análisis de Componente Principal
7.
J Environ Manage ; 124: 108-14, 2013 Jul 30.
Artículo en Inglés | MEDLINE | ID: mdl-23624428

RESUMEN

This work describes the efficiency of photoelectrocatalysis based on Ti/TiO2 nanotubes in the degradation of the azo dyes Disperse Red 1, Disperse Red 13 and Disperse Orange 1 and to remove their toxic properties, as an alternative method for the treatment of effluents and water. For this purpose, the discoloration rate, total organic carbon (TOC) removal, and genotoxic, cytotoxic and mutagenic responses were determined, using the comet, micronucleus and cytotoxicity assays in HepG2 cells and the Salmonella mutagenicity assay. In a previous study it was found that the surfactant Emulsogen could contribute to the low mineralization of the dyes (60% after 4 h of treatment), which, in turn, seems to account for the mutagenicity of the products generated. Thus this surfactant was not added to the chloride medium in order to avoid this interference. The photoelectrocatalytic method presented rapid discoloration and the TOC reduction was ≥87% after 240 min of treatment, showing that photoelectrocatalysis is able to mineralize the dyes tested. The method was also efficient in removing the mutagenic activity and cytotoxic effects of these three dyes. Thus it was concluded that photoelectrocatalysis was a promising method for the treatment of aqueous samples.


Asunto(s)
Compuestos Azo/toxicidad , Cloruros/análisis , Colorantes/toxicidad , Técnicas Electroquímicas/métodos , Nanotubos , Titanio/química , Contaminantes Químicos del Agua/toxicidad , Pruebas de Carcinogenicidad , Catálisis , Pruebas de Mutagenicidad , Procesos Fotoquímicos , Agua/química
8.
J Toxicol Environ Health A ; 75(16-17): 1000-11, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-22852850

RESUMEN

Chrysin is one of the natural flavonoids present in plants, and large amounts are present in honey and propolis. In addition to anticancer, antioxidation, and anti-inflammatory activities, chrysin has also been reported to be an inhibitor of aromatase, an enzyme converting testosterone into estrogen. The present study evaluated the mutagenicity of this flavonoid using micronucleus (MN) with HepG2 cells and Salmonella. Cell survival after exposure to different concentrations of chrysin was also determined using sulforhodamine B (SRB) colorimetric assay in HepG2 cells and the influence of this flavonoid on growth of cells in relation to the cell cycle and apoptosis. The MN test showed that from 1 to 15 µM of this flavonoid mutagenic activity was noted in HepG2 cells. The Salmonella assay demonstrated a positive response to the TA100 Salmonella strain in the presence or absence of S9, suggesting that this compound acted on DNA, inducing base pair substitution before or after metabolism via cytochrome P-450. The SRB assay illustrated that chrysin promoted growth inhibition of HepG2 cells in both periods studied (24 and 48 h). After 24 h of exposure it was noted that the most significant results were obtained with a concentration of 50 µM, resulting in 83% inhibition and SubG0 percentage of 12%. After 48 h of incubation cell proliferation inhibition rates (97% at 50 µM) were significantly higher. Our results showed that chrysin is a mutagenic and cytotoxic compound in cultured human HepG2 cells and Salmonella typhimurium. Although it is widely accepted that flavonoids are substances beneficial to health, one must evaluate the risk versus benefit relationship and concentrations of these substances to which an individual may be exposed.


Asunto(s)
Inhibidores de la Aromatasa/farmacología , Flavonoides/farmacología , Salmonella/efectos de los fármacos , Ciclo Celular , Proliferación Celular/efectos de los fármacos , Estradiol/química , Estradiol/metabolismo , Células Hep G2 , Hepatocitos/efectos de los fármacos , Hepatocitos/enzimología , Humanos , Pruebas de Micronúcleos , Estructura Molecular , Mutagénesis , Testosterona/química , Testosterona/metabolismo
9.
Braz J Med Biol Res ; 55: e11631, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34909910

RESUMEN

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has caused several problems in healthcare systems around the world, as to date, there is no effective and specific treatment against all forms of COVID-19. Currently, drugs with therapeutic potential are being tested, including antiviral, anti-inflammatory, anti-malarial, immunotherapy, and antibiotics. Although antibiotics have no direct effect on viral infections, they are often used against secondary bacterial infections, or even as empiric treatment to reduce viral load, infection, and replication of coronaviruses. However, there are many concerns about this therapeutic approach as it may accelerate and/or increase the long-term rates of antimicrobial resistance (AMR). We focused this overview on exploring candidate drugs for COVID-19 therapy, including antibiotics, considering the lack of specific treatment and that it is unclear whether the widespread use of antibiotics in the treatment of COVID-19 has implications for the emergence and transmission of multidrug-resistant bacteria.


Asunto(s)
COVID-19 , Pandemias , Antibacterianos/uso terapéutico , Antivirales/uso terapéutico , Humanos , SARS-CoV-2
10.
Mutat Res ; 703(2): 200-8, 2010 Dec 21.
Artículo en Inglés | MEDLINE | ID: mdl-20851777

RESUMEN

The treatment of textile effluents by the conventional method based on activated sludge followed by a chlorination step is not usually an effective method to remove azo dyes, and can generate products more mutagenic than the untreated dyes. The present work evaluated the efficiency of conventional chlorination to remove the genotoxicity/mutagenicity of the azo dyes Disperse Red 1, Disperse Orange 1, and Disperse Red 13 from aqueous solutions. The comet and micronucleus assays with HepG2 cells and the Salmonella mutagenicity assay were used. The degradation of the dye molecules after the same treatment was also evaluated, using ultraviolet and visible absorption spectrum measurements (UV-vis), high performance liquid chromatography coupled to a diode-array detector (HPLC-DAD), and total organic carbon removal (TOC) analysis. The comet assay showed that the three dyes studied induced damage in the DNA of the HepG2 cells in a dose-dependent manner. After chlorination, these dyes remained genotoxic, although with a lower damage index (DI). The micronucleus test showed that the mutagenic activity of the dyes investigated was completely removed by chlorination, under the conditions tested. The Salmonella assay showed that chlorination reduced the mutagenicity of all three dyes in strain YG1041, but increased the mutagenicity of Disperse Red 1 and Disperse Orange 1 in strain TA98. With respect to chemical analysis, all the solutions showed rapid discoloration and a reduction in the absorbance bands characteristic of the chromophore group of each dye. However, the TOC was not completely removed, showing that chlorination of these dyes is not efficient in mineralizing them. It was concluded that conventional chlorination should be used with caution for the treatment of aqueous samples contaminated with azo dyes.


Asunto(s)
Compuestos Azo/toxicidad , Colorantes/toxicidad , Halogenación , Mutágenos/toxicidad , Contaminantes Químicos del Agua/toxicidad , Antimutagênicos/farmacología , Células Hep G2 , Humanos , Pruebas de Mutagenicidad
11.
J Periodontal Res ; 44(6): 714-7, 2009 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-19453853

RESUMEN

BACKGROUND AND OBJECTIVE: Hereditary gingival fibromatosis (HGF) is a benign disorder manifested by fibrous enlargement of keratinized gingiva. Evidence exists concerning the role of matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) in mediating normal and pathological processes, including HGF. Nevertheless, there are few and contradictory results on the analysis of MMPs and TIMPs transcripts in this pathology. MATERIAL AND METHODS: We studied the expression of the transcripts encoding MMP-1, -2 and -9 and TIMP-1 and -2 in gingival biopsies, obtained from three cases of HGF within a family, by semi-quantitative reverse transcriptase-polymerase chain reaction analysis. Samples were also processed for gelatin zymography. RESULTS: Except for MMP-9, most transcripts presented a higher level of expression in biopsies from HGF patients compared with control subjects. Accordingly, MMP-9 gelatinase activity was detected at low and similar levels among samples. Moreover, MMP-2 enzymatic activity was not detected at all. CONCLUSION: The mRNA expression of MMP-1 and -2 and TIMP-1 and -2 does not explain the gingival overgrowth presented in these cases. In addition, it is suggested that the gene expression of those molecules in the course of HGF is regulated at the translational or post-translational level.


Asunto(s)
Fibromatosis Gingival/genética , Metaloproteinasas de la Matriz/análisis , Inhibidores Tisulares de Metaloproteinasas/análisis , Biopsia , Precursores Enzimáticos/análisis , Precursores Enzimáticos/genética , Fibromatosis Gingival/enzimología , Regulación Enzimológica de la Expresión Génica/genética , Encía/enzimología , Encía/patología , Humanos , Metaloproteinasa 1 de la Matriz/análisis , Metaloproteinasa 1 de la Matriz/genética , Metaloproteinasa 2 de la Matriz/análisis , Metaloproteinasa 2 de la Matriz/genética , Metaloproteinasa 9 de la Matriz/análisis , Metaloproteinasa 9 de la Matriz/genética , Metaloproteinasas de la Matriz/genética , ARN Mensajero/análisis , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Inhibidor Tisular de Metaloproteinasa-1/análisis , Inhibidor Tisular de Metaloproteinasa-1/genética , Inhibidor Tisular de Metaloproteinasa-2/análisis , Inhibidor Tisular de Metaloproteinasa-2/genética , Inhibidores Tisulares de Metaloproteinasas/genética , Transcripción Genética/genética
12.
Sci Rep ; 7(1): 13181, 2017 10 13.
Artículo en Inglés | MEDLINE | ID: mdl-29030568

RESUMEN

The occurrence of emotions in non-human animals has been the focus of debate over the years. Recently, an interest in expanding this debate to non-tetrapod vertebrates and to invertebrates has emerged. Within vertebrates, the study of emotion in teleosts is particularly interesting since they represent a divergent evolutionary radiation from that of tetrapods, and thus they provide an insight into the evolution of the biological mechanisms of emotion. We report that Sea Bream exposed to stimuli that vary according to valence (positive, negative) and salience (predictable, unpredictable) exhibit different behavioural, physiological and neuromolecular states. Since according to the dimensional theory of emotion valence and salience define a two-dimensional affective space, our data can be interpreted as evidence for the occurrence of distinctive affective states in fish corresponding to each the four quadrants of the core affective space. Moreover, the fact that the same stimuli presented in a predictable vs. unpredictable way elicited different behavioural, physiological and neuromolecular states, suggests that stimulus appraisal by the individual, rather than an intrinsic characteristic of the stimulus, has triggered the observed responses. Therefore, our data supports the occurrence of emotion-like states in fish that are regulated by the individual's perception of environmental stimuli.


Asunto(s)
Peces/fisiología , Animales , Cognición/fisiología , Emociones/fisiología
13.
Braz. j. med. biol. res ; 55: e11631, 2022. tab
Artículo en Inglés | LILACS-Express | LILACS | ID: biblio-1350333

RESUMEN

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has caused several problems in healthcare systems around the world, as to date, there is no effective and specific treatment against all forms of COVID-19. Currently, drugs with therapeutic potential are being tested, including antiviral, anti-inflammatory, anti-malarial, immunotherapy, and antibiotics. Although antibiotics have no direct effect on viral infections, they are often used against secondary bacterial infections, or even as empiric treatment to reduce viral load, infection, and replication of coronaviruses. However, there are many concerns about this therapeutic approach as it may accelerate and/or increase the long-term rates of antimicrobial resistance (AMR). We focused this overview on exploring candidate drugs for COVID-19 therapy, including antibiotics, considering the lack of specific treatment and that it is unclear whether the widespread use of antibiotics in the treatment of COVID-19 has implications for the emergence and transmission of multidrug-resistant bacteria.

14.
Immunol Lett ; 28(3): 227-32, 1991 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-1679416

RESUMEN

Monoclonal antibodies directed against the Thy-1 molecule or the CD3 complex were used to analyze the activation of T cells from mice acutely infected with Trypanosoma cruzi. When stimulated with G7, a mitogenic anti-Thy-1 monoclonal antibody, spleen cells from infected mice showed a markedly reduced or absent response that could not be restored by varying the culture time or the antibody concentration. However, cells from acutely infected animals proliferated to 145-2C11, an anti-CD3 monoclonal antibody. Flow cytometric analysis showed that the impaired response to G7 could not be attributed to a lack of expression of Thy-1 or CD3. Indeed, G7 seemed to deliver a positive signal to the cells since the proliferative response was completely restored by the addition of PMA. Moreover, purified T cells from infected mice responded to G7 in the presence of accessory cells from uninfected animals. These results suggest that a defective co-stimulatory cell function could be involved in the immunosuppression. In addition, our data present evidence against a generalized T cell anergy in the acute phase of the disease, since CD3-mediated activation was normal.


Asunto(s)
Antígenos de Diferenciación de Linfocitos T/inmunología , Antígenos de Superficie/inmunología , Enfermedad de Chagas/inmunología , Activación de Linfocitos , Receptores de Antígenos de Linfocitos T/inmunología , Linfocitos T/inmunología , Trypanosoma cruzi/inmunología , Enfermedad Aguda , Animales , Anticuerpos Monoclonales/inmunología , Complejo CD3 , Citometría de Flujo , Ratones , Ratones Endogámicos , Bazo/inmunología , Acetato de Tetradecanoilforbol/farmacología , Antígenos Thy-1
15.
Infect Control Hosp Epidemiol ; 22(7): 443-8, 2001 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-11583214

RESUMEN

OBJECTIVE: To evaluate the possible presence of vancomycin-resistant Staphylococcus aureus (VRSA) in a Brazilian hospital. DESIGN: Epidemiological and laboratory investigation of nosocomial VRSA. METHODS: 140 methicillin-resistant S aureus strains isolated between November 1998 and October 1999 were screened for susceptibility to vancomycin. The screening was carried out by using brain-heart infusion agar (BHIA) supplemented with 4, 6, and 8 microg/mL of vancomycin. The minimum inhibitory concentration (MIC) determination was carried out as standardized by the National Committee for Clinical Laboratory Standards using the broth macrodilution, agar-plate dilution, and E-test methods. PATIENTS: Hospitalized patients exposed to vancomycin. RESULTS: 5 of the 140 isolates had a vancomycin MIC of 8 microg/mL by broth macrodilution, agar plate dilution, and E-test methods. Four VRSA strains were isolated from patients in a burn unit who had been treated with vancomycin for more than 30 days, and one from an orthopedic unit patient who had received vancomycin treatment for 7 days. Pulsed-field gel electrophoresis characterized four of the VRSA strains as belonging to the Brazilian endemic clone. All five strains were negative for vanA, vanB, and vanC genes by polymerase chain reaction. Transmission electron microscopy of the five strains revealed significantly thickened cell walls. One patient died due to infection caused by the VRSA strain. CONCLUSIONS: This is the first report of isolation of VRSA in Brazil and the first report of isolation of multiple VRSA strains from one facility over a relatively short period of time. This alerts us to the possibility that VRSA may be capable of nosocomial transfer if adequate hospital infection control measures are not taken.


Asunto(s)
Infección Hospitalaria/tratamiento farmacológico , Infecciones Estafilocócicas/tratamiento farmacológico , Staphylococcus aureus/efectos de los fármacos , Staphylococcus aureus/aislamiento & purificación , Resistencia a la Vancomicina , Antibacterianos/farmacología , Antibacterianos/uso terapéutico , Brasil , Infección Hospitalaria/prevención & control , Femenino , Hospitales Públicos , Humanos , Control de Infecciones/métodos , Masculino , Resistencia a la Meticilina , Pruebas de Sensibilidad Microbiana , Infecciones Estafilocócicas/prevención & control , Vancomicina/farmacología , Vancomicina/uso terapéutico
17.
Braz J Infect Dis ; 5(4): 163-70, 2001 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-11712960

RESUMEN

The objective of this study was to characterize patterns of the Brazilian endemic clone of methicillin-resistant Staphylococcus aureus (MRSA) from hospitals throughout Brazil. We studied 83 MRSA strains isolated from patients hospitalized in 27 public and private hospitals in 19 cities located in 14 Brazilian states from September, 1995, to June, 1997. The MRSA strains were typed using antibiograms, bacteriophage typing and pulsed field gel electrophoresis (PFGE). The analysis of genomic DNA by PFGE showed that 65 isolates presented the same PFGE pattern. This pattern was present in all of the hospitals studied indicating the presence of an endemic MRSA clone widely disseminated throughout Brazilian hospitals (BEC). All isolates belonging to the BEC proved to be resistant to ciprofloxacin, erythromycin, lincomycin, trimethoprim-sulphamethoxazole, and tetracycline. Variable susceptibility to these drugs was found only in isolates belonging to clones other than the BEC. The results show that, among MRSA, the BEC is common in Brazil. The best method for mapping changes in the frequency of this clone among MRSA is pulsed field gel electrophoresis. Use of molecular mapping is an important tool for monitoring the spread of potentially dangerous microbes.


Asunto(s)
Infección Hospitalaria/epidemiología , Resistencia a la Meticilina/genética , Infecciones Estafilocócicas/epidemiología , Staphylococcus aureus/genética , Antibacterianos/farmacología , Tipificación de Bacteriófagos , Brasil/epidemiología , Infección Hospitalaria/microbiología , ADN Bacteriano/genética , Electroforesis en Gel de Campo Pulsado , Hospitales Privados , Hospitales Públicos , Humanos , Control de Infecciones , Pruebas de Sensibilidad Microbiana , Infecciones Estafilocócicas/microbiología , Staphylococcus aureus/clasificación , Staphylococcus aureus/efectos de los fármacos , Staphylococcus aureus/aislamiento & purificación
18.
Braz J Infect Dis ; 7(1): 32-43, 2003 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-12807690

RESUMEN

Staphylococcus aureus has long been recognised as an important pathogen in human disease. Serious staphylococcal infections can frequently occur in inpatients and may lead to dire consequences, especially for therapy with antimicrobial agents. The increase in the frequency of Methicillin-Resistant Staphylococcus aureus (MRSA) as the causal agent of nosocomial infection and the possibility of emergence of resistance to vancomycin demands a quick and trustworthy characterization of isolates and identification of clonal spread within hospitals. Enough information must be generated to permit the implementation of appropriate measures for control of infection, so that outbreaks can be contained. Molecular typing techniques reviewed in this manuscript include: plasmid profile analysis, analysis of chromosomal DNA after enzymatic restriction, Southern blotting, pulsed field gel electrophoresis (PFGE), techniques involving polymerase chain reaction and multilocus sequence typing (MLST). Repetitive DNA Sequence PCR (rep-PCR) may be used for screening due to its practicality, low cost and reproducibility. Because of its high discriminatory power Pulsed-Field Gel Electrophoresis (PFGE) still remains the gold standard for MRSA typing. New techniques with higher reproducibility and discriminatory power, such as Multi-Locus Sequence Typing (MLST), are appearing. These are mostly useful for global epidemiology studies. Molecular typing techniques are invaluable tools for the assessment of putative MRSA outbreaks and so should be extensively used for this purpose.


Asunto(s)
Técnicas de Tipificación Bacteriana , Infección Hospitalaria/microbiología , ADN Bacteriano/análisis , Resistencia a la Meticilina/genética , Infecciones Estafilocócicas/microbiología , Staphylococcus aureus/clasificación , Técnicas de Tipificación Bacteriana/métodos , Técnicas de Tipificación Bacteriana/normas , Brasil/epidemiología , Cromosomas Bacterianos/química , Infección Hospitalaria/epidemiología , Infección Hospitalaria/prevención & control , Electroforesis en Gel de Campo Pulsado , Genotipo , Humanos , Plásmidos/análisis , Reacción en Cadena de la Polimerasa , Secuencias Repetitivas de Ácidos Nucleicos , Infecciones Estafilocócicas/epidemiología , Staphylococcus aureus/efectos de los fármacos , Staphylococcus aureus/genética
19.
Braz J Infect Dis ; 7(3): 173-4, 2003 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-14499039

RESUMEN

Vancomycin-resistant enterococci strains (VRE) is an important pathogen related with hospital infections in many countries, presenting limited or no therapeutic options for treating serious infections. VRE has presented some different genotypes been VanA and VanB considered to be the most important in hospital environments. In the present study the authors investigated the prevalence of van genes (A, B an C) among clinical isolates of VRE in a five month period at a large tertiary hospital in Sao Paulo, Brazil. The results showed the presence of vanA, but not vanB or vanC in all 43 strains of E. faecalis and five E. faecium studied. The results bring an important issue, due to the possibility of resistance spread of vanA genes, to be monitored and solved by the hospital infection control team and the microbiology and molecular biology laboratories at tertiary Hospitals.


Asunto(s)
Enterococcus faecalis/genética , Enterococcus faecium/genética , Resistencia a la Vancomicina/genética , Proteínas Bacterianas/genética , Brasil , Ligasas de Carbono-Oxígeno/genética , Infección Hospitalaria/microbiología , Enterococcus faecalis/efectos de los fármacos , Enterococcus faecium/efectos de los fármacos , Humanos , Reacción en Cadena de la Polimerasa
20.
Oxid Med Cell Longev ; 2013: 194192, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-23577220

RESUMEN

2-[(2,6-Dichlorobenzylidene)amino]-5,6-dihydro-4H-cyclopenta[b]thiophene-3-carbonitrile, 5TIO1, is a new 2-aminothiophene derivative with promising pharmacological activities. The aim of this study was to evaluate its antioxidant activity in different areas of mice central nervous system. Male Swiss adult mice were intraperitoneally treated with Tween 80 dissolved in 0.9% saline (control group) and 5TIO1 (0.1, 1, and 10 mg kg(-1)). Brain homogenates-hippocampus, striatum, frontal cortex, and cerebellum-were obtained after 24 h of observation. Superoxide dismutase and catalase activities, lipid peroxidation and nitrite content were measured using spectrophotometrical methods. To clarify the 5TIO1's mechanism on oxidative stress, western blot analysis of superoxide dismutase and catalase was also performed. 5TIO1 decreased lipid peroxidation and nitrite content in all brain areas and increased the antioxidant enzymatic activities, specially, in cerebellum. The data of Western blot analysis did not demonstrate evidence of the upregulation of these enzymes after the administration of this compound. Our findings strongly support that 5TIO1 can protect the brain against neuronal damages regularly observed during neuropathologies.


Asunto(s)
Antioxidantes/farmacología , Encéfalo/metabolismo , Estrés Oxidativo , Bases de Schiff/farmacología , Tiofenos/farmacología , Animales , Antioxidantes/química , Encéfalo/efectos de los fármacos , Catalasa/metabolismo , Cerebelo/enzimología , Cerebelo/metabolismo , Cuerpo Estriado/enzimología , Cuerpo Estriado/metabolismo , Lóbulo Frontal/enzimología , Lóbulo Frontal/metabolismo , Hipocampo/enzimología , Hipocampo/metabolismo , Inyecciones Intraperitoneales , Peroxidación de Lípido , Masculino , Ratones , Nitritos/metabolismo , Estrés Oxidativo/efectos de los fármacos , Bases de Schiff/química , Superóxido Dismutasa/metabolismo , Tiofenos/química
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