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1.
Appl Microbiol Biotechnol ; 106(7): 2503-2516, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35352150

RESUMO

The biocatalytic production of fuels and chemicals from plant biomass represents an attractive alternative to fossil fuel-based refineries. In this context, the mining and characterization of novel biocatalysts can promote disruptive innovation opportunities in the field of lignocellulose conversion and valorization. In the present work, we conducted the biochemical and structural characterization of two novel hydroxycinnamic acid catabolic enzymes, isolated from a lignin-degrading microbial consortium, a feruloyl-CoA synthetase, and a feruloyl-CoA hydratase-lyase, named LM-FCS2 and LM-FCHL2, respectively. Besides establishing the homology model structures for novel FCS and FCHL members with unique characteristics, the enzymes presented interesting biochemical features: LM-FCS2 showed stability in alkaline pHs and was able to convert a wide array of p-hydroxycinnamic acids to their respective CoA-thioesters, including sinapic acid; LM-FCHL2 efficiently converted feruloyl-CoA and p-coumaroyl-CoA into vanillin and 4-hydroxybenzaldehyde, respectively, and could produce vanillin directly from ferulic acid. The coupled reaction of LM-FCS2 and LM-FCHL2 produced vanillin, not only from commercial ferulic acid but also from a crude lignocellulosic hydrolysate. Collectively, this work illuminates the structure and function of two critical enzymes involved in converting ferulic acid into high-value molecules, thus providing valuable concepts applied to the development of plant biomass biorefineries. KEY POINTS: • Comprehensive characterization of feruloyl-CoA synthetase from metagenomic origin. • Novel low-resolution structures of hydroxycinnamate catabolic enzymes. • Production of vanillin via enzymatic reaction using lignocellulosic hydrolysates.


Assuntos
Lignina , Metagenoma , Escherichia coli/genética , Hiperlipidemia Familiar Combinada , Lignina/metabolismo , Solo
2.
Am J Physiol Gastrointest Liver Physiol ; 307(4): G420-9, 2014 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-24970779

RESUMO

Despite well-known intestinal epithelial barrier impairment and visceral hypersensitivity in irritable bowel syndrome (IBS) patients and IBS-like models, structural and physical changes in the mucus layer remain poorly understood. Using a water avoidance stress (WAS) model, we aimed at evaluating whether 1) WAS modified gut permeability, visceral sensitivity, mucin expression, biochemical structure of O-glycans, and related mucus physical properties, and 2) whether Lactobacillus farciminis treatment prevented these alterations. Wistar rats received orally L. farciminis or vehicle for 14 days; at day 10, they were submitted to either sham or 4-day WAS. Intestinal paracellular permeability and visceral sensitivity were measured in vivo. The number of goblet cells and Muc2 expression were evaluated by histology and immunohistochemistry, respectively. Mucosal adhesion of L. farciminis was determined ex situ. The mucin O-glycosylation profile was obtained by mass spectrometry. Surface imaging of intestinal mucus was performed at nanoscale by atomic force microscopy. WAS induced gut hyperpermeability and visceral hypersensitivity but did not modify either the number of intestinal goblet cells or Muc2 expression. In contrast, O-glycosylation of mucins was strongly affected, with the appearance of elongated polylactosaminic chain containing O-glycan structures, associated with flattening and loss of the mucus layer cohesive properties. L. farciminis bound to intestinal Muc2 and prevented WAS-induced functional alterations and changes in mucin O-glycosylation and mucus physical properties. WAS-induced functional changes were associated with mucus alterations resulting from a shift in O-glycosylation rather than from changes in mucin expression. L. farciminis treatment prevented these alterations, conferring epithelial and mucus barrier strengthening.


Assuntos
Mucosa Intestinal/metabolismo , Mucina-2/biossíntese , Probióticos/uso terapêutico , Estresse Psicológico/fisiopatologia , Animais , Colo/metabolismo , Corticosterona/sangue , Glicosilação , Células Caliciformes/fisiologia , Mucosa Intestinal/microbiologia , Lactobacillus/metabolismo , Masculino , Muco/metabolismo , Permeabilidade , Ratos , Ratos Wistar
3.
Psicol Reflex Crit ; 37(1): 9, 2024 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-38483652

RESUMO

BACKGROUND: Dating violence in adolescence is a serious public health issue due to its significant impact on mental health and its significant predictive value for intimate partner violence in adulthood. Universal and selective programs can contribute to the prevention of this issue. Nonetheless, there are few selective programs with evidence of feasibility in contexts of social vulnerability. OBJECTIVE: The present study examined evidence of the feasibility of a dating violence selective prevention program for girls in foster care by monitoring process indicators during the implementation phase of a pilot study. METHODS: The program, originally designed for adolescents in the general population, was adapted to the context of girls at risk. The pilot study was conducted in the southern region of Brazil and involved the participation of six girls aged between 15 and 17. Both quantitative and qualitative measures were used, and the data were explored through frequency analysis, the Jacobson and Truax test, and content analysis. RESULTS: The study identified favorable evidence regarding demand, acceptability, and adaptation of the intervention. On the other hand, contextual and institutional barriers hindered recruitment and restricted the reach of the intervention. CONCLUSION: Although there are changes to be made to improve the program's applicability in its specific context, it should be emphasized that this study provides evidence to maintain the methods and content of the intervention.

4.
Diseases ; 12(1)2024 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-38248380

RESUMO

Massive vaccination positively impacted the SARS-CoV-2 pandemic, being a strategy to increase the titers of neutralizing antibodies (NAbs) in the population. Assessing NAb levels and understanding the kinetics of NAb responses is critical for evaluating immune protection. In this study, we optimized and validated a PRNT50 assay to assess 50% virus neutralization and evaluated its accuracy to measure NAbs to the original strain or variant of SARS-CoV-2. The optimal settings were selected, such as the cell (2 × 105 cells/well) and CMC (1.5%) concentrations and the viral input (~60 PFU/well) for PRNT-SARS-CoV-2 with cut-off point = 1.64 log5 based on the ROC curve (AUC = 0.999). The validated PRNT-SARS-CoV-2 assay presented high accuracy with an intraassay precision of 100% for testing samples with different NAb levels (low, medium, and high titers). The method displays high selectivity without cross-reactivity with dengue (DENV), measles (MV), zika (ZIKV), and yellow fever (YFV) viruses. In addition, the standardized PRNT-SARS-CoV-2 assay presented robustness when submitted to controlled variations. The validated PRNT assay was employed to test over 1000 specimens from subjects with positive or negative diagnoses for SARS-CoV-2 infection. Patients with severe COVID-19 exhibited higher levels of NAbs than those presenting mild symptoms for both the Wuhan strain and Omicron. In conclusion, this study provides a detailed description of an optimized and validated PRNT50 assay to monitor immune protection and to subsidize surveillance policies applied to epidemiologic studies of COVID-19.

5.
J Immunol Methods ; 522: 113568, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-37748728

RESUMO

Although it is considered the reference for quantification of neutralizing antibodies, classical method of the plaque reduction neutralization test (PRNT) is labor intensive, requires specific equipment and inputs, besides a long time for its finalization, even in the micro-PRNT version (in 96-well plates). It has a higher sample throughput, however the smaller wells make the reading of plaques more difficult. With an immunoenzymatic revelation step and a semi-automated reading, the µFRN-HRP (micro Focus Reduction Neutralization - Horseradish Peroxidase) is a faster and more efficient test for the quantification of YF neutralizing antibodies. This study aimed to standardize, validate, and compare it with the reference method in 6-well plates (PRNT). Once the execution protocol was standardized, precision, accuracy, selectivity, and robustness were evaluated to validate the µFRN-HRP. In addition, 200 sera of vaccinees were processed by the µFRN-HRP and by the micro-PRNT to compare with the reference test, estimating agreement by Intraclass Correlation Coefficient (ICC). The standardization and validation of the µFRN-HRP was carried out successfully. Weak to moderate agreement was observed between µFRN-HRP and PRNT for titers in reciprocal dilution, while the same comparison between the classical tests resulted in a better ICC. However, titers in milli-international units obtained by µFRN-HRP showed a substantial agreement with PRNT, while the agreement between micro-PRNT and PRNT was inferior. Therefore, µFRN-HRP can be used in the confirmation of natural YF infection and immune response to vaccination, replacing the micro-PRNT, gaining agility, while preserving the specificity of the result.


Assuntos
Anticorpos Neutralizantes , Febre Amarela , Humanos , Testes de Neutralização/métodos , Anticorpos Antivirais , Padrões de Referência
6.
Mol Omics ; 19(10): 743-755, 2023 Dec 04.
Artigo em Inglês | MEDLINE | ID: mdl-37581345

RESUMO

Microbial biostimulants have emerged as a sustainable alternative to increase the productivity and quality of important crops. Despite this, the effects of the treatment on plant metabolism are poorly understood. Thus, this study investigated the metabolic response of common bean (Phaseolus vulgaris) related to the treatment with a biostimulant obtained from the extract of Corynebacterium glutamicum that showed positive effects on the development, growth, and yield of crops previously. By untargeted metabolomic analysis using UHPLC-MS/MS, plants and seeds were subjected to treatment with the biostimulant. Under ideal growth conditions, the plants treated exhibited higher concentration levels of glutamic acid, nicotiflorin and glycosylated lipids derived from linolenic acid. The foliar application of the biostimulant under water stress conditions increased the chlorophyll content by 17% and induced the accumulation of flavonols, mainly quercetin derivatives. Also, germination seed assays exhibited longer radicle lengths for seeds treated compared to the untreated control even in the absence of light (13-18% increase, p-value <0.05). Metabolomic analysis of the seeds indicated changes in concentration levels of amino acids (tryptophan, phenylalanine, tyrosine, glutamine, and arginine) and their derivatives. The results point out the enhancement of abiotic stress tolerance and the metabolic processes triggered in this crop associated with the treatment with the biostimulant, giving the first insights into stress tolerance mechanisms in P. vulgaris.


Assuntos
Corynebacterium glutamicum , Phaseolus , Phaseolus/química , Phaseolus/metabolismo , Phaseolus/microbiologia , Espectrometria de Massas em Tandem , Estresse Fisiológico , Clorofila/metabolismo
7.
Biotechnol Biofuels Bioprod ; 16(1): 5, 2023 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-36624471

RESUMO

BACKGROUND: Lignin is an attractive alternative for producing biobased chemicals. It is the second major component of the plant cell wall and is an abundant natural source of aromatic compounds. Lignin degradation using microbial oxidative enzymes that depolymerize lignin and catabolize aromatic compounds into central metabolic intermediates is a promising strategy for lignin valorization. However, the intrinsic heterogeneity and recalcitrance of lignin severely hinder its biocatalytic conversion. In this context, examining microbial degradation systems can provide a fundamental understanding of the pathways and enzymes that are useful for lignin conversion into biotechnologically relevant compounds. RESULTS: Lignin-degrading catabolism of a novel Rhodosporidium fluviale strain LM-2 was characterized using multi-omic strategies. This strain was previously isolated from a ligninolytic microbial consortium and presents a set of enzymes related to lignin depolymerization and aromatic compound catabolism. Furthermore, two catabolic routes for producing 4-vinyl guaiacol and vanillin were identified in R. fluviale LM-2. CONCLUSIONS: The multi-omic analysis of R. fluviale LM-2, the first for this species, elucidated a repertoire of genes, transcripts, and secreted proteins involved in lignin degradation. This study expands the understanding of ligninolytic metabolism in a non-conventional yeast, which has the potential for future genetic manipulation. Moreover, this work unveiled critical pathways and enzymes that can be exported to other systems, including model organisms, for lignin valorization.

8.
Viruses ; 15(7)2023 06 30.
Artigo em Inglês | MEDLINE | ID: mdl-37515173

RESUMO

Successful SARS-CoV-2 inactivation allows its safe use in Biosafety Level 2 facilities, and the use of the whole viral particle helps in the development of analytical methods and a more reliable immune response, contributing to the development and improvement of in vitro and in vivo assays. In order to obtain a functional product, we evaluated several inactivation protocols and observed that 0.03% beta-propiolactone for 24 h was the best condition tested, as it promoted SARS-CoV-2 inactivation above 99.99% and no cytopathic effect was visualized after five serial passages. Moreover, RT-qPCR and transmission electron microscopy revealed that RNA quantification and viral structure integrity were preserved. The antigenicity of inactivated SARS-CoV-2 was confirmed by ELISA using different Spike-neutralizing monoclonal antibodies. K18-hACE2 mice immunized with inactivated SARS-CoV-2, formulated in AddaS03TM, presented high neutralizing antibody titers, no significant weight loss, and longer survival than controls from a lethal challenge, despite RNA detection in the oropharyngeal swab, lung, and brain. This work emphasizes the importance of using different techniques to confirm viral inactivation and avoid potentially disastrous contamination. We believe that an efficiently inactivated product can be used in several applications, including the development and improvement of molecular diagnostic kits, as an antigen for antibody production as well as a control for non-clinical trials.


Assuntos
COVID-19 , SARS-CoV-2 , Camundongos , Animais , Formação de Anticorpos , COVID-19/prevenção & controle , Anticorpos Antivirais , Imunização , Ensaio de Imunoadsorção Enzimática , Anticorpos Neutralizantes
9.
Perspect Behav Sci ; 43(1): 57-103, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32440645

RESUMO

Stimulus-stimulus pairing (SSP) is a procedure used by behavior analysis practitioners that capitalizes on respondent conditioning processes to elicit vocalizations. These procedures usually are implemented only after other, more customary methods (e.g., standard echoic training via modeling) have been exhausted. Unfortunately, SSP itself has mixed research support, probably because certain as-yet-unidentified procedural variations are more effective than others. Even when SSP produces (or increases) vocalizations, its effects can be short-lived. Although specific features of SSP differ across published accounts, fundamental characteristics include presentation of a vocal stimulus proximal with presentation of a preferred item. In the present article, we draw parallels between SSP procedures and autoshaping, review factors shown to affect autoshaping, and interpret autoshaping research for suggested SSP tests and applications. We then call for extended use and reporting of SSP in behavior-analytic treatments. Finally, three bridges created by this article are identified: basic-applied, respondent-operant, and behavior analysis with other sciences.

10.
Psicol. reflex. crit ; 37: 9, 2024. tab
Artigo em Inglês | LILACS-Express | LILACS, INDEXPSI | ID: biblio-1558772

RESUMO

Abstract Background Dating violence in adolescence is a serious public health issue due to its significant impact on mental health and its significant predictive value for intimate partner violence in adulthood. Universal and selective programs can contribute to the prevention of this issue. Nonetheless, there are few selective programs with evidence of feasibility in contexts of social vulnerability. Objective The present study examined evidence of the feasibility of a dating violence selective prevention program for girls in foster care by monitoring process indicators during the implementation phase of a pilot study. Methods The program, originally designed for adolescents in the general population, was adapted to the context of girls at risk. The pilot study was conducted in the southern region of Brazil and involved the participation of six girls aged between 15 and 17. Both quantitative and qualitative measures were used, and the data were explored through frequency analysis, the Jacobson and Truax test, and content analysis. Results The study identified favorable evidence regarding demand, acceptability, and adaptation of the intervention. On the other hand, contextual and institutional barriers hindered recruitment and restricted the reach of the intervention. Conclusion Although there are changes to be made to improve the program's applicability in its specific context, it should be emphasized that this study provides evidence to maintain the methods and content of the intervention.

11.
Viruses ; 11(12)2019 12 16.
Artigo em Inglês | MEDLINE | ID: mdl-31888285

RESUMO

Zika virus (ZIKV) was first discovered in 1947 in Uganda but was not considered a public health threat until 2007 when it found to be the source of epidemic activity in Asia. Epidemic activity spread to Brazil in 2014 and continued to spread throughout the tropical and subtropical regions of the Americas. Despite ZIKV being zoonotic in origin, information about transmission, or even exposure of non-human vertebrates and mosquitoes to ZIKV in the Americas, is lacking. Accordingly, from February 2017 to March 2018, we sought evidence of sylvatic ZIKV transmission by sampling whole blood from approximately 2000 domestic and wild vertebrates of over 100 species in West-Central Brazil within the active human ZIKV transmission area. In addition, we collected over 24,300 mosquitoes of at least 17 genera and 62 species. We screened whole blood samples and mosquito pools for ZIKV RNA using pan-flavivirus primers in a real-time reverse-transcription polymerase chain reaction (RT-PCR) in a SYBR Green platform. Positives were confirmed using ZIKV-specific envelope gene real-time RT-PCR and nucleotide sequencing. Of the 2068 vertebrates tested, none were ZIKV positive. Of the 23,315 non-engorged mosquitoes consolidated into 1503 pools tested, 22 (1.5%) with full data available showed some degree of homology to insect-specific flaviviruses. To identify previous exposure to ZIKV, 1498 plasma samples representing 62 species of domestic and sylvatic vertebrates were tested for ZIKV-neutralizing antibodies by plaque reduction neutralization test (PRNT90). From these, 23 (1.5%) of seven species were seropositive for ZIKV and negative for dengue virus serotype 2, yellow fever virus, and West Nile virus, suggesting potential monotypic reaction for ZIKV. Results presented here suggest no active transmission of ZIKV in non-human vertebrate populations or in alternative vector candidates, but suggest that vertebrates around human populations have indeed been exposed to ZIKV in West-Central Brazil.


Assuntos
Infecção por Zika virus/epidemiologia , Infecção por Zika virus/virologia , Zika virus , Animais , Brasil/epidemiologia , Culicidae , Geografia Médica , Humanos , Mosquitos Vetores , Testes de Neutralização , Vigilância em Saúde Pública , Estudos Soroepidemiológicos , Infecção por Zika virus/transmissão , Zoonoses
12.
Nutrients ; 10(6)2018 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-29882841

RESUMO

We aimed to determine whether a cumulative dose of vitamin D3 produces the same effects on the serum concentration of 25(OH)D3 if it is given daily or monthly. This is a monocentric, two-armed, randomized, interventional, open, and parallel study conducted from November 2016 to March 2017 in Belgium. We randomized 60 subjects with vitamin D deficiency to receive 2000 IU vitamin D3 daily or 50,000 IU monthly. The same cumulative dose of vitamin D3 was given to each treatment group (150,000 IU). The 25(OH)D3 serum concentrations from baseline to day 75 were 14.3 ± 3.7 to 27.8 ± 3.9 ng/mL in the monthly group and 14.1 ± 3.4 to 28.8 ± 5.4 ng/mL in the daily group. The mean change versus the baseline level was significantly different between the groups at day 2, 4, 7, and 14 and no longer different from day 25. One day after the intake of vitamin D3, as expected, serum 25(OH)D3 and 1,25(OH)2D3 increased significantly in the monthly group, whereas they did not change significantly in the daily group. The median time to reach the 20 ng/mL target concentration was significantly different in the two groups, in favor of the monthly regimen (1 day versus 14 days; p = 0.02). In conclusion, a monthly administration of 50,000 IU vitamin D3 provides an effective tool for a rapid normalization of 25(OH)D3 in deficient subjects. A daily administration of the same cumulative dose is similarly effective but takes two weeks longer to reach the desirable level of 20 ng/mL.


Assuntos
Colecalciferol/administração & dosagem , Suplementos Nutricionais , Deficiência de Vitamina D/tratamento farmacológico , Adulto , Bélgica , Biomarcadores/sangue , Calcifediol/sangue , Colecalciferol/sangue , Esquema de Medicação , Feminino , Fator de Crescimento de Fibroblastos 23 , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Tempo , Resultado do Tratamento , Regulação para Cima , Deficiência de Vitamina D/sangue , Deficiência de Vitamina D/diagnóstico , Adulto Jovem
13.
Brain Struct Funct ; 223(2): 883-895, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29022091

RESUMO

The medial prefrontal cortex (mPFC) is a key area for the regulation of numerous brain functions including stress response and cognitive processes. This brain area is also particularly affected by adversity during early life. Using an animal model in rats, we recently demonstrated that maternal exposure to a high-fat diet (HFD) prevents maternal separation (MS)-induced gene expression alterations in the developing PFC and attenuates several long-term deleterious behavioral effects of MS. In the present study, we ask whether maternal HFD could protect mPFC neurons of pups exposed to early life stress by examining dendritic morphology and spine density in juvenile [postnatal day (PND) 21] and adult rats submitted to MS. Dams were fed either a control or an HFD throughout gestation and lactation, and pups were submitted to MS from PND2 to PND14. We report that maternal HFD prevents MS-induced spine loss at PND21 and dendritic atrophy at adulthood. Furthermore, we show in adult MS rats that PFC-dependent memory extinction deficits are prevented by maternal HFD. Finally, perinatal HFD exposure reverses gut leakiness following stress in pups and seems to exert an anti-stress effect in dams. Overall, our work demonstrates that maternal HFD affects the developing brain and suggests that nutrition, possibly through gut-brain interactions, could modulate mPFC sensitivity to early stress.


Assuntos
Envelhecimento , Dendritos/patologia , Dieta Hiperlipídica , Troca Materno-Fetal/fisiologia , Córtex Pré-Frontal/patologia , Estresse Psicológico/patologia , Estresse Psicológico/prevenção & controle , Animais , Animais Recém-Nascidos , Contagem de Células , Dendritos/ultraestrutura , Feminino , Trato Gastrointestinal/fisiopatologia , Masculino , Neurônios/patologia , Neurônios/ultraestrutura , Odorantes , Permeabilidade , Córtex Pré-Frontal/crescimento & desenvolvimento , Gravidez , Ratos , Ratos Wistar , Privação de Água
14.
Inflamm Bowel Dis ; 24(4): 792-805, 2018 03 19.
Artigo em Inglês | MEDLINE | ID: mdl-29529198

RESUMO

Background: Peroxisome proliferator-activated receptor-gamma (PPARγ) exerts anti-inflammatory effects and is therefore a potential target in ulcerative colitis (UC). A novel PPARγ agonist (AS002) developed for local action was evaluated ex vivo in biopsies from UC patients and in vivo in mice with low-grade dextran sodium sulfate (DSS)- and trinitrobenzene sulfonic acid (TNBS)-induced colitis. Methods: Colonic biopsies from UC patients (n = 18) and healthy controls (n = 6) were incubated with AS002 or rosiglitazone (positive control) to measure mRNA expression of the PPARγ-responsive gene ADIPOPHILIN and protein levels of UC-related cytokines (enzyme-linked immunosorbent assay). AS002 absorption was determined in the colonic mucosa of UC patients. DSS-colitis mice received PPARγ agonists or vehicle daily by intrarectal administration starting 2 days before induction of colitis (preventive) or from days 3 to 8 (curative). Myeloperoxidase (MPO) and cytokine levels in colonic mucosa were determined. In addition, AS002 effects were studied in TNBS colitis. Results: AS002 displayed an absorption pattern of a lipophilic drug totally metabolized in the mucosa. AS002 and rosiglitazone increased ADIPOPHILIN mRNA expression (3-fold) and decreased TNF-α, IL-1ß, and IL-13 levels in human UC biopsies. In DSS, in both preventive and curative treatment and in TNBS colitis, AS002 protected against macroscopic and histological damage and lowered MPO and TNF-α, IL-1ß, and IL-13 levels. Conclusions: AS002 triggers anti-inflammatory PPARγ activity in the human colonic mucosa of UC patients and prevents and reverses colitis in mice. Our data suggest that AS002 has potential for topical maintenance treatment of UC, which warrants further studies in vivo in patients.


Assuntos
Colite Ulcerativa/tratamento farmacológico , Colite/prevenção & controle , Mucosa Intestinal/efeitos dos fármacos , PPAR gama/agonistas , Perilipina-2/metabolismo , Adulto , Idoso , Animais , Colite/induzido quimicamente , Colite Ulcerativa/metabolismo , Colo/patologia , Citocinas/efeitos dos fármacos , Citocinas/metabolismo , Sulfato de Dextrana/administração & dosagem , Feminino , Humanos , Mucosa Intestinal/metabolismo , Masculino , Camundongos Endogâmicos BALB C , Pessoa de Meia-Idade , PPAR gama/metabolismo , Perilipina-2/genética , Peroxidase/efeitos dos fármacos , Peroxidase/metabolismo , Rosiglitazona/farmacologia , Ácido Trinitrobenzenossulfônico/administração & dosagem
15.
Behav Processes ; 75(2): 115-28, 2007 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-17395402

RESUMO

Resurgence refers to the transient recovery of previously reinforced, but presently not reinforced, responding when more recently reinforced responding is extinguished. The primary purpose of our research was to determine how differential resurgence results from the procedures used to eliminate that responding. There were three conditions in each of five experiments. In Condition 1, key pecking by pigeons was maintained under a two-component multiple variable-interval (VI) 30-s VI 30-s schedule. In Condition 2, this pecking was eliminated in different ways across components. In Condition 3, extinction was in effect for all responses, and resurgence of key pecking was compared across components. These three conditions were repeated for most pigeons, and the procedures used to eliminate responding in Condition 2 varied across experiments. In Experiment 1, there was greater resurgence, and an earlier onset of it, after a differential-reinforcement-of-other-behavior (DRO) schedule than after a VI schedule was correlated with pecking an alternative key. Experiments 2 and 3 showed that the differential resurgence in Experiment 1 probably was not due to conditional stimulus control or the periodicity of food delivery, respectively. In Experiment 4, there was no systematic difference in resurgence after either a DRO schedule or a VI schedule correlated with treadle pressing. In Experiment 5, there was greater resurgence, and/or an earlier onset of it, after a VI schedule correlated with treadle pressing than after a VI schedule correlated with pecking an alternative key. Taken together, the results showed that the reinforcement of an alternative key-peck response was the most effective means of reducing subsequent key-peck resurgence. The relation of these results to an understanding of resurgence is discussed.


Assuntos
Comportamento Animal , Condicionamento Clássico , Extinção Psicológica , Inibição Psicológica , Esquema de Reforço , Animais , Columbidae , Tempo de Reação , Reforço Psicológico , Fatores de Tempo
16.
Behav Processes ; 71(2-3): 157-63, 2006 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-16364564

RESUMO

The question of how temporal control of responding might be influenced by contingency changes in other contexts was investigated. Each of three pigeons first was exposed to a two-component multiple schedule in which a two-key free-operant psychophysical procedure operated in one component and a variable-interval schedule operated in the other component. The variable-interval schedule then was changed to extinction while the free-operant psychophysical procedure remained unchanged. Finally, the variable-interval schedule was reintroduced. Response rates on the left key and the estimated temporal threshold under the free-operant psychophysical procedure increased for each pigeon when the alternate component schedule was changed to extinction and then decreased again when the variable-interval schedule was reintroduced. The results suggest one way that temporal control is affected by its context, and may be interpreted through the direct effects of overall reinforcement rate on temporal control mechanisms or the disruptive effects of alternative sources of reinforcement on temporally controlled behavior.


Assuntos
Comportamento Animal/fisiologia , Condicionamento Operante/fisiologia , Limiar Diferencial/fisiologia , Tempo de Reação/fisiologia , Percepção do Tempo/fisiologia , Animais , Columbidae , Meio Ambiente , Psicofísica
17.
Nutrients ; 8(5)2016 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-27213447

RESUMO

Vitamin D3 is known to be liposoluble and its release could be a factor limiting the rate of absorption. It was presumed that the presence of fat could favor absorption of vitamin D3. However, as bioavailability is related not only to the active molecules but also to the formulations and excipients used, the optimization of the pharmaceutical form of vitamin D3 is also important. The objective of this study was to evaluate if there is a food effect on absorption when a high dose of vitamin D3 is completely solubilized in an oily solution. In the present cross-over study, 88 subjects were randomized and received a single dose of 50,000 IU of vitamin D3 in fasting state or with a standardized high-fat breakfast. Assessment of serum concentrations of 25 hydroxyvitamin D3 (25(OH)D3) was performed three, five, seven, 14, 30 and 60 days after supplementation. In fed and fast conditions, the 25(OH)D3 serum concentrations were significantly higher than the baseline value three days after administration and remained significantly higher during the first month. No significant difference between fasting vs. fed conditions was observed. It is therefore concluded that the vitamin D3 absorption from an oily solution was not influenced by the presence or absence of a meal.


Assuntos
Calcifediol/sangue , Colecalciferol/administração & dosagem , Gorduras na Dieta/administração & dosagem , Suplementos Nutricionais , Interações Alimento-Droga , Adulto , Bélgica , Disponibilidade Biológica , Biomarcadores/sangue , Desjejum , Colecalciferol/sangue , Colecalciferol/farmacocinética , Estudos Cross-Over , Gorduras na Dieta/metabolismo , Feminino , Absorção Gastrointestinal , Humanos , Masculino , Pessoa de Meia-Idade , Período Pós-Prandial , Adulto Jovem
18.
J Neurosurg Pediatr ; 15(4): 392-8, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25658248

RESUMO

OBJECT: There is a known association of hydrocephalus with encephaloceles. Risk factors for hydrocephalus and neurological deficit were ascertained in a series of patients born with an encephalocele. METHODS: A retrospective analysis was undertaken of patients treated for encephaloceles at Children's Hospital Los Angeles between 1994 and 2012. The following factors were evaluated for their prognostic value: age at presentation, sex, location of encephalocele, size, contents, microcephaly, presence of hydrocephalus, CSF leak, associated cranial anomalies, and neurological outcome. RESULTS: Seventy children were identified, including 38 girls and 32 boys. The median age at presentation was 2 months. The mean follow-up duration was 3.7 years. Encephalocele location was classified as anterior (n = 14) or posterior (n = 56) to the coronal suture. The average maximum encephalocele diameter was 4 cm (range 0.5-23 cm). Forty-seven encephaloceles contained neural tissue. Eight infants presented at birth with CSF leaking from the encephalocele, with 1 being infected. Six patients presented with hydrocephalus, while 11 developed progressive hydrocephalus postoperatively. On univariate analysis, the presence of neural tissue, cranial anomalies, encephalocele size of at least 2 cm, seizure disorder, and microcephaly were each positively associated with hydrocephalus. On multivariate logistic regression modeling, the single prognostic factor for hydrocephalus of borderline statistical significance was the presence of neural tissue (odds ratio [OR] = 5.8, 95% confidence interval [CI] = 0.8-74.0). Fourteen patients had severe developmental delay, 28 had mild/moderate delay, and 28 were neurologically normal. On univariate analysis, the presence of cranial anomalies, larger size of encephalocele, hydrocephalus, and microcephaly were positively associated with neurological deficit. In the multivariable model, the only statistically significant prognostic factor for neurological deficit was presence of hydrocephalus (OR 17.2, 95% CI 1.7-infinity). CONCLUSIONS: In multivariate models, the presence of neural tissue was borderline significantly associated with hydrocephalus and the presence of hydrocephalus was significantly associated with neurological deficit. The location of the encephalocele did not have a statistically significant association with incidence of hydrocephalus or neurological deficit. In contrast to modestly good/fair neurological outcome in children with an encephalocele without hydrocephalus, the presence of hydrocephalus resulted in a far worse neurological outcome.


Assuntos
Encefalocele/complicações , Encefalocele/cirurgia , Hidrocefalia/complicações , Microcefalia/complicações , Doenças do Sistema Nervoso/etiologia , Fatores Etários , Vazamento de Líquido Cefalorraquidiano/complicações , Criança , Pré-Escolar , Progressão da Doença , Feminino , Humanos , Hidrocefalia/etiologia , Hidrocefalia/terapia , Incidência , Lactente , Modelos Logísticos , Los Angeles/epidemiologia , Masculino , Doenças do Sistema Nervoso/epidemiologia , Valor Preditivo dos Testes , Prognóstico , Estudos Retrospectivos , Fatores de Risco , Convulsões/etiologia , Fatores Sexuais , Resultado do Tratamento
19.
Nutrients ; 7(7): 5413-22, 2015 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-26151178

RESUMO

Many people worldwide are vitamin D (VTD) deficient or insufficient, and there is still no consensus on the dose of VTD that should be administered to achieve a 25(OH)D concentration of 20 or 30 ng/mL. In this study, we aimed to determine an adapted supplementation of VTD able to quickly and safely increase the vitamin D status of healthy adults with low 25(OH)D. One hundred and fifty (150) subjects were randomized into three groups, each to receive, orally, a loading dose of 50,000, 100,000 or 200,000 IU of VTD3 at Week 0, followed by 25,000, 50,000 or 100,000 IU at Week 4 and Week 8. Whereas 25(OH)D baseline values were not different between groups (p = 0.42), a significant increase was observed at Week 12 (p < 0.0001) with a mean change from baseline of 7.72 ± 5.08, 13.3 ± 5.88 and 20.12 ± 7.79 ng/mL. A plateau was reached after eight weeks. No related adverse event was recorded. This study demonstrated a linear dose-response relationship with an increase in 25(OH)D levels proportional to the dose administered. In conclusion, a loading dose of 200,000 IU VTD3 followed by a monthly dose of 100,000 IU is the best dosing schedule to quickly and safely correct the VTD status.


Assuntos
Colecalciferol/administração & dosagem , Deficiência de Vitamina D/tratamento farmacológico , Vitamina D/análogos & derivados , Vitaminas/administração & dosagem , Adolescente , Adulto , Suplementos Nutricionais , Relação Dose-Resposta a Droga , Método Duplo-Cego , Esquema de Medicação , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Vitamina D/sangue , Deficiência de Vitamina D/sangue , Adulto Jovem
20.
PLoS One ; 10(9): e0136048, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26367538

RESUMO

The present study aimed at detecting the exogenously applied probiotic Lactobacillus farciminis in rats, after exposure to IBS-like chronic stress, based on 4-day Water Avoidance Stress (WAS). The presence of L. farciminis in both ileal and colonic mucosal tissues was demonstrated by FISH and qPCR, with ileum as the preferential niche, as for the SFB population. A different spatial distribution of the probiotic was observed: in the ileum, bacteria were organized in micro-colonies more or less close to the epithelium whereas, in the colon, they were mainly visualized far away from the epithelium. When rats were submitted to WAS, the L. farciminis population substantially decreased in both intestinal regions, due to a stress-induced increase in colonic motility and defecation, rather than a modification of bacterial binding to the intestinal mucin Muc2.


Assuntos
Mucosa Intestinal/microbiologia , Lactobacillus/patogenicidade , Estresse Psicológico/microbiologia , Animais , Colo/microbiologia , Colo/ultraestrutura , Íleo/microbiologia , Íleo/ultraestrutura , Mucosa Intestinal/ultraestrutura , Masculino , Mucina-2/metabolismo , Ligação Proteica , Ratos , Ratos Wistar , Estresse Psicológico/patologia
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