Evaluation of calibrated and uncalibrated optical imaging approaches for relative cerebral oxygen metabolism measurements in awake mice.

Objective. The continuous delivery of oxygen is critical to sustain brain function, and therefore, measuring brain oxygen consumption can provide vital physiological insight. In this work, we examine the impact of calibration and cerebral blood flow (CBF) measurements on the computation of the relative changes in the cerebral metabolic rate of oxygen consumption (rCMRO2) from hemoglobin-sensitive intrinsic optical imaging data. Using these data, we calculate rCMRO2, and calibrate the model using an isometabolic stimulus.Approach. We used awake head-fixed rodents to obtain hemoglobin-sensitive optical imaging data to test different calibrated and uncalibrated rCMRO2models. Hypercapnia was used for calibration and whisker stimulation was used to test the impact of calibration.Main results. We found that typical uncalibrated models can provide reasonable estimates of rCMRO2with differences as small as 7%-9% compared to their calibrated models. However, calibrated models showed lower variability and less dependence on baseline hemoglobin concentrations. Lastly, we found that supplying the model with measurements of CBF significantly reduced error and variability in rCMRO2change calculations.Significance. The effect of calibration on rCMRO2calculations remains understudied, and we systematically evaluated different rCMRO2calculation scenarios that consider including different measurement combinations. This study provides a quantitative comparison of these scenarios to evaluate trade-offs that can be vital to the design of blood oxygenation sensitive imaging experiments for rCMRO2calculation.

Translation and validation of the evidence-based practice attitude scale (EBPAS-15) to Brazilian Portuguese: Examining providers' perspective about evidence-based parent intervention.

Background: Few existing evidence-based parent interventions (EBPIs) for prevention and treatment of child and youth mental health disorders are implemented in low-middle-income countries. This study aimed to translate and confirm the factor structure of the Evidence-Based Practice Attitude Scale (EBPAS-15) survey in Brazilian Portuguese with the goal of examining providers' perspective about EBPIs. Methods: We translated and back translated the EBPAS-15 from English to Brazilian Portuguese. Participants were recruited via snowball sampling and data were collected using an online survey from July of 2018 through January of 2020. A confirmatory factor analysis was conducted to determine if the scale retained its original structure. Open-ended questions about providers' perspectives of their own clinical practice were coded using the Theoretical Domains Framework (TDF). Analyses included data from 362 clinicians (318 women, 41 men) from 20 of the 27 states of Brazil. Participants on average were 26.7 years old, held specialist degrees in the field of psychology, actively worked as therapists, and practiced in private clinics. Results: The translation of the EBPAS to Brazilian Portuguese retained the same four-factor structure as the English version except for dropping one item from the Divergence domain. When asked about the challenges in their practices, providers generally referred to parents as clients with little skills to discipline their children and lacking knowledge about child development. Discussion: The Brazilian version of the EBPAS-15 is promising, but future research should consider using quantitative data alongside qualitative information to better understand providers' attitudes about evidence-based interventions to inform implementation efforts. Trial registration: N/A.

Meningeal inflammatory response and fibrous tissue remodeling around intracortical implants: An in vivo two-photon imaging study.

Meningeal inflammation and encapsulation of neural electrode arrays is a leading cause of device failure, yet little is known about how it develops over time or what triggers it. This work characterizes the dynamic changes of meningeal inflammatory cells and collagen-I in order to understand the meningeal tissue response to neural electrode implantation. We use in vivo two-photon microscopy of CX3CR1-GFP mice over the first month after electrode implantation to quantify changes in inflammatory cell behavior as well as meningeal collagen-I remodeling. We define a migratory window during the first day after electrode implantation hallmarked by robust inflammatory cell migration along electrodes in the meninges as well as cell trafficking through meningeal venules. This migratory window attenuates by 2 days post-implant, but over the next month, the meningeal collagen-I remodels to conform to the surface of the electrode and thickens. This work shows that there are distinct time courses for initial meningeal inflammatory cell infiltration and meningeal collagen-I remodeling. This may indicate a therapeutic window early after implantation for modulation and mitigation of meningeal inflammation.

Amaranth 7S globulin Langmuir films and its interaction with l-α-dipalmitoilphosphatidilcholine at the air-fluid interface.

Amaranth seeds are one of the more promising food ingredients, due to their high protein content, among which the most important are storage proteins known as globulins. However, little is known about the physicochemical of the globulin proteins. In this work, we study the physicochemical behavior of films made of amaranth 7S globulin and its interaction with a model membrane made of L-α-dipalmitoylphosphatidylcholine (L-α-DPPC) at the air-liquid interface. The study was done by means of Langmuir balance, Brewster angle microscopy (BAM), fluorescence microscopy, and atomic force microscopy (AFM). We found that isotherms of pure 7S globulin directly deposited on either water or buffer subphases behave similarly and globulin forms a condensed film made of globular and denature structures, which was confirmed by BAM observations. Good mixtures of the protein with L-α-DPPC are formed at low surface pressure. However, they phase separate from moderate to high surface pressure as observed by BAM. Isotherms detect the presence of the protein in the mixture with L-α-DPPC, but we were unable to detect it through BAM or AFM. We show that fluorescence microscopy is a very good technique to detect the presence of the protein when it is well-mixed within the LE phase of the lipid. AFM images clearly show the formation of protein mono- and multilayers, and in phase mode, we detected domains that are formed by protein and LE lipid phase, which were corroborated by fluorescence microscopy. We have shown that globulin 7S mix well with lipid phases, which could be important in food applications as stabilizers or emulsifiers, but we also show that they can phase separate with a moderate to high surface pressure.

Evaluación de la conveniencia del cambio de vía de administración de rivastigmina en pacientes con enfermedad de Alzheimer / Evaluation of the convenience of changing the rivastigmine administration route in patients with Alzheimer disease

Introducción: Los parches transdérmicos de rivastigmina para el tratamiento de la enfermedad de Alzheimer presentan posibles beneficios respecto a las cápsulas por su absorción sostenida a través de la piel, buena tolerabilidad local y reducción de problemas gastrointestinales. Objetivo: Evaluar la tolerabilidad gastrointestinal y cutánea y la necesidad de titulación para obtener dosis óptimas de rivastigmina transdérmica en pacientes con Alzheimer previamente tratados oralmente. Pacientes y métodos: Se llevó a cabo un estudio multicéntrico, aleatorizado y abierto que incluyó a 142 pacientes con Alzheimer de leve a moderado y previamente tratados con rivastigmina oral (6-12 mg/día). La muestra fue aleatorizada a: continuar con tratamiento oral durante 3 meses (n = 49); cambio al parche sin titulación (9,5 mg/día durante 3 meses, n = 47) o cambio al parche con titulación (4,6 mg/día por 1 mes seguido de 9,5 mg/día por 2 meses, n = 43). Resultados: La incidencia de efectos adversos gastrointestinales fue del 6,1% en el grupo tratado oralmente y del 4,2% en el grupo tratado con parche sin titulación (p = 0,908). La tolerabilidad cutánea fue buena (n = 15, 16,7%), sin observarse acontecimientos adversos graves. El tratamiento con parche fue considerado muy fácil de utilizar por el 72% de pacientes en comparación con el 30% con tratamiento oral (p = 0,0005). El 60% se mostraron satisfechos con el parche, mientras que únicamente un 14% se declaró satisfecho con las cápsulas (p < 0,0001). Conclusiones: Los parches de rivastigmina presentan un perfil de tolerabilidad similar a las cápsulas y se asocian con una mayor satisfacción de los pacientes (AU)

Introduction: Rivastigmine transdermal patches for the treatment of Alzheimer’s disease (AD) have potential benefits compared to capsules because of their sustained absorption through the skin, good local tolerability and reduction of gastrointestinal problems. Purpose: To assess gastrointestinal and skin tolerability and the need for optimal dose titration of rivastigmine transdermal patches in Alzheimer’s disease patients previously treated with oral rivastigmine. Patients and methods: A multicenter, randomized, open-label study including patients with mild to moderate AD (DSM-IV) previously treated with rivastigmine capsules (6-12 mg/day) was conducted. Patients were randomized to: continue with capsules for 3 months (n = 49) or switch to rivastigmine patch without titration (9.5 mg/day for 3 months; n = 48), or switch to rivastigmine patch with titration (4.6 mg/day for 1 month followed by 9.5 mg/day for 2 months, n = 43). Results: Incidence of gastrointestinal adverse events was 6.1% in the group treated orally and 4.2% in the group treated with non-titrated patches (P = .908). Skin tolerability was good (n = 15, 16.7%) without any serious adverse events registered. Patch treatment was considered very easy to use by 72% of patients compared with 30% in the group with oral treatment (P = .0005). 60% of patients were satisfied with the patch, while only 14% were satisfied with capsules (P < .0001). Conclusions: Rivastigmine patches have a tolerability profile similar to that shown by capsules, but are associated with greater patient satisfaction (AU)

Evaluation of the convenience of changing the rivastigmine administration route in patients with Alzheimer disease.

INTRODUCTION: Rivastigmine transdermal patches for the treatment of Alzheimer's disease (AD) have potential benefits compared to capsules because of their sustained absorption through the skin, good local tolerability and reduction of gastrointestinal problems. PURPOSE: To assess gastrointestinal and skin tolerability and the need for optimal dose titration of rivastigmine transdermal patches in Alzheimer's disease patients previously treated with oral rivastigmine. PATIENTS AND METHODS: A multicenter, randomized, open-label study including patients with mild to moderate AD (DSM-IV) previously treated with rivastigmine capsules (6-12 mg/day) was conducted. Patients were randomized to: continue with capsules for 3 months (n=49) or switch to rivastigmine patch without titration (9.5mg/day for 3 months; n=48), or switch to rivastigmine patch with titration (4.6 mg/day for 1 month followed by 9.5mg/day for 2 months, n=43). RESULTS: Incidence of gastrointestinal adverse events was 6.1% in the group treated orally and 4.2% in the group treated with non-titrated patches (P=.908). Skin tolerability was good (n=15, 16.7%) without any serious adverse events registered. Patch treatment was considered very easy to use by 72% of patients compared with 30% in the group with oral treatment (P=.0005). 60% of patients were satisfied with the patch, while only 14% were satisfied with capsules (P<.0001). CONCLUSIONS: Rivastigmine patches have a tolerability profile similar to that shown by capsules, but are associated with greater patient satisfaction.

Globulin 11S and its mixture with L-dipalmitoylphosphatidylcholine at the air/liquid interface.

Langmuir films of globulin 11S protein, l-dipalmitoylphosphatidylcholine (L-DPPC), and mixtures of both on water and on buffer subphases were studied. Brewster angle microscopy (BAM) was used to characterize in situ the films morphology along Pi-A isotherms at the air/liquid interface. The L-DPPC monolayer on water behaved as has been reported extensively in the literature but a slight increase on surface pressure and a notable change in domain morphology is observed on buffer. This difference in domain behavior is due to the stabilization interaction of the LE phase by the buffer ions. On the other hand, the protein monolayer was prepared by direct deposit or injection below the surface. Both methods formed mostly a condensed film, with a multilayer formed by globular aggregates in the first method with the two subphases. However, the second method showed different behavior of the protein films depending on the subphase; on water the protein formed a homogeneous film with some globule aggregates, but on buffer a remarkably well-organized monolayer was observed by atomic force microscopy (AFM). Mixtures of globulin 11S and L-DPPC were prepared using both methods for the protein film formation at the air/fluid interface. BAM showed that the mixtures formed coexistence regions between two condensed phases, whose domains of both phases behave like liquids. Fingering phenomena were observed at the interface between protein-rich and L-DPPC-rich domains, which indicates that both phases are fluid. AFM images of the mixtures show the formation of protein- or L-DPPC-rich domains. The liquidlike behavior could be explained due to different sizes of the protein and the L-DPPC, the minority compound in each kind of domain produces defects making them behave as liquids. Interestingly enough, as the monolayer is compressed to higher surface pressure, the lipid molecules are squeezed out and complete separation of the protein and L-DPPC is produced. Furthermore, we present evidence that the protein/L-DPPC mixtures produce films with holes, which might indicate its tendency to form hollow aggregates that could have some relevance in water-channel formation for in vivo seed germination.

Interaction of the cationic peptide bactenecin with phospholipid monolayers at the air-water interface: i interaction with 1,2-dipalmitoyl-sn-glycero-3-phosphatidilcholine.

In this work we have investigated the influence of NaCl on the adsorption of the antimicrobial cationic peptide bactenecin in the monolayer of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) at the air-water interface, as a function of NaCl concentrations in the subphase. We show that the effect of the salt concentration on DPPC monolayers is a monotonic decrease of the liquid-condensed-liquid-expanded (LC-LE) coexistence region. By contrast, the effect of the bactenecin adsorption at the DPPC monolayer not only removed the LC-LE coexistence region plateau, but also shifted the DPPC isotherms to higher pressures and increased the compressibility of the DPPC/bactenecin monolayers with respect to the pure DPPC monolayer around the LC phase. Analysis of the domain structure, obtained by Brewster angle and atomic force microscopes, indicates that the salt concentration in the subphase builds an electrostatic barrier, increasing the rigidity of DPPC monolayers and limiting the bactenecin adsorption at the LC-LE phase coexistence.

Characterisation of the RNA-dependent RNA polymerase from Rabbit hemorrhagic disease virus produced in Escherichia coli.

All positive-strand RNA viruses encode a RNA-dependent RNA polymerase which in most cases has been only identified on the basis of its sequence conservation. Catalytic activity has been experimentally demonstrated in only a handful of these viral proteins, including that from Rabbit hemorrhagic disease virus. Studies from our laboratory have reported that RHDV RNA polymerase produced in Escherichia coli was enzymatically active showing poly(A)-dependent poly(U) polymerase as well as RNA polymerase activity on heteropolymeric substrates. In this work, we have investigated the in vitro activity of the recombinant 3Dpol from RHDV, including ion requirements, resistance to inhibitors, substrate specificity as well as data on the initiation mechanism of the template-linked products derived from heteropolymeric RNA substrates. Our study demonstrates that in an in vitro reaction recombinant RHDV RNA polymerase generated the minus strand of the heteropolymeric RNA substrates by a "copy-back" mechanism that initiated at the template 3'-terminal OH.

Mutation analysis of the GDD sequence motif of a calicivirus RNA-dependent RNA polymerase.

The RNA-dependent RNA polymerase from rabbit hemorrhagic disease virus, a calicivirus, is known to have a conserved GDD amino acid motif and several additional regions of sequence homology with all types of polymerases. To test whether both aspartic acid residues are in fact involved in the catalytic activity and metal ion coordination of the enzyme, several defined mutations have been made in order to replace them by glutamate, asparagine, or glycine. All six mutant enzymes were produced in Escherichia coli, and their in vitro poly(U) polymerase activity was characterized. The results demonstrated that the first aspartate residue was absolutely required for enzyme function and that some flexibility existed with respect to the second, which could be replaced by glutamate.

Evaluation of respiratory artifact correction techniques in multishot spiral functional MRI using receiver operator characteristic analyses.

Navigator corrections and low-spatial frequency (LSF) oversampling are investigated as methods for reducing respiration-related effects in multishot functional MRI. Both techniques take advantage of the smoothly varying or nearly constant phase variations linked to the respiration cycle. These techniques were tested in functional MRI studies with spiral k-space acquisitions. Receiver operator characteristic (ROC) analyses and the temporal variance averaged across the brain were used to evaluate their effectiveness. Both methods were found to increase the area under the ROC curve and to reduce the standard deviation, with the LSF oversampling method being more effective.

Expression of enzymatically active rabbit hemorrhagic disease virus RNA-dependent RNA polymerase in Escherichia coli.

The rabbit hemorrhagic disease virus (RHDV) (isolate AST/89) RNA-dependent RNA-polymerase (3Dpol) coding region was expressed in Escherichia coli by using a glutathione S-transferase-based vector, which allowed milligram purification of a homogeneous enzyme with an expected molecular mass of about 58 kDa. The recombinant polypeptide exhibited rifampin- and actinomycin D-resistant, poly(A)-dependent poly(U) polymerase. The enzyme also showed RNA polymerase activity in in vitro reactions with synthetic RHDV subgenomic RNA in the presence or absence of an oligo(U) primer. Template-size products were synthesized in the oligo(U)-primed reactions, whereas in the absence of added primer, RNA products up to twice the length of the template were made. The double-length RNA products were double stranded and hybridized to both positive- and negative-sense probes.

Nonlinear aspects of the BOLD response in functional MRI.

Functional magnetic resonance imaging (fMRI) using blood oxygenation level-dependent (BOLD) contrast has progressed rapidly and is commonly used to study function in many regions of the human brain. This paper introduces a method for characterizing the linear and nonlinear properties of the hemodynamic response. Such characterization is essential for accurate prediction of time-course behavior. Linearity of the BOLD response was examined in the primary visual cortex for manipulations of the stimulus amplitude and duration. Stimuli of 1, 2, 4, and 8 s duration (80% contrast) and 10, 20, 40, and 80% contrast (4 s duration) were used to test the hemodynamic response. Superposition of the obtained responses was performed to determine if the BOLD response is nonlinear. The nonlinear characteristics of the BOLD response were assessed using a Laplacian linear system model cascaded with a broadening function. Discrepancies between the model and the observed response provide an indirect measure of the nonlinearity of the response. The Laplacian linear system remained constant within subjects so the broadening function can be used to absorb nonlinearities in the response. The results show that visual stimulation under 4 s in duration and less than 40% contrast yield strong nonlinear responses.

Estimating test-retest reliability in functional MR imaging. II: Application to motor and cognitive activation studies.

Functional magnetic resonance imaging (fMRI) using blood oxygenation contrast has rapidly spread into many application areas. In this paper, a new statistical model is used to evaluate the reliability of fMRI activation in a finger opposition motor paradigm for both within-session and between-session data and in a working memory paradigm for between-session data. A slice prescription procedure for between-session reproducibility is introduced. Estimates are made for the probabilities of correctly and falsely classifying voxels as active or inactive and receiver operator characteristic curves are generated. In the motor paradigm, estimated between-session reliability was found to be somewhat reduced relative to within-session reliability; however, this includes additional sources of variation and may not reflect intrinsically lower reliability. After matching false-positive classification probabilities, between-session reliability was found to be nearly identical for both motor and cognitive activation paradigms.

Comparative effects of intestinal absorption of folic acid and methyltetrahydrofolic acid in chronic ethanol-fed rats.

This study concerns in vivo folic acid and methyltetrahydrofolic acid (MTHF) absorption by the whole intestinal surface after 20 weeks of 30% ethanol ingestion in drinking water. The results were compared with control rats fed ad libitum. The total intestinal serosal areas were similar in ethanol-fed and control rats. Significant increases in intestinal length, and decreases in tissue wet and dry weights were found in ethanol-fed rats. Serum folic acid concentrations were significantly less in the animals which had ingested ethanol than in the control rats. Intestinal folic acid absorption was significantly increased at lower substrate concentrations (0.5 and 1 microM), while no difference was observed at 2.5 microM in the ethanol-fed rats. Folic acid absorption relative to tissue wet weight showed significant increases at all tested concentrations in the ethanol-fed rats. Intestinal MTHF absorption showed no significant changes at 0.5 microM MTHF concentration, and an increase was observed in the absorption values at 1 and 2.5 microM concentrations in the ethanol-fed rats. When expressed as tissue wet weight, MTHF absorption values in ethanol-fed rats increased at 1 and 2.5 microM but did not differ at 0.5 microM substrate concentrations. The above results indicate compensatory responses in the folic acid and MTHF intestinal absorption after chronic ethanol ingestion. These effects are observed when the whole intestinal surface is evaluated.

The effect of ethanol on intestinal L-leucine absorption in rats.

The chronic effect of ethanol on leucine absorption by the whole rat intestine (between duodenum and rectum) was studied using an in vivo multiple-pass perfusion technique. Leucine concentrations in the perfusion medium were 5, 10 and 25 mM respectively in successive passes. Ethanol was administered in drinking water during a one month induction period and then for a four week period of ad libitum ingestion of 30% ethanol solution. The results were compared with ad libitum-fed control rats. The total calorie consumption due to the chow diet plus ethanol increased in the rats which had ingested ethanol when compared with that of the controls. The daily protein intake in ethanol-fed rats was less than that of the controls. No significant differences in morphometric tissue parameters were found between the two experimental groups. Chronic ethanol ingestion provoked a slight (but not significant) decrease in net leucine absorption at 5 mM leucine concentration. In contrast, minor increases in the absorption values were found at 10 and 25 mM leucine concentrations. These findings suggest that the diminished active mechanisms of leucine absorption provoked by ethanol ingestion are compensated for by the enhanced diffusive processes, the passage of the nutrients through the whole intestine, and that the low protein consumption of ethanol-fed rats in ad libitum conditions isn't enough to provoke significant decreases in leucine absorption by the whole intestine.

Effect of chronic ethanol on D-galactose absorption by the rat whole intestinal surface.

The in vivo absorption of D-galactose by rat whole intestinal surface after 4 weeks of 30% ethanol ingestion in drinking water has been studied, and the results were compared with ad lib-fed control rats. The total serosal intestinal area was determined by integration obtaining similar values between control and alcohol-treated groups. In the caecum surface of ethanol-fed rats slight but not significant increases were found, while the jejunum area decreased with respect to control rats. Total galactose absorption during 10 min of perfusion was slightly increased in ethanol-fed rats but these results were not significant with the substrate concentrations tested. When absorption data were referred to serosal surface, the absorption/cm2 values in ethanol-fed rats were increased at the studied galactose concentrations although these results were only statistically significant at 10 mM. In conclusion, the present data indicates a slight increase in D-galactose absorptive capacity by the whole intestine in ethanol-fed rats which suggest that the tissue traditionally not evaluated such as caecum and colon could modify the functional response to the absorption nutrients.