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1.
Public Health ; 225: 305-310, 2023 Dec.
Article in English | MEDLINE | ID: mdl-37963420

ABSTRACT

OBJECTIVES: The COVID-19 pandemic hit Portugal in March 2020, causing widespread disruption to various aspects of society. While extensive research has been conducted on the significance of socio-economic disparities in infection risk, this study aims to enhance our understanding of their evolving relationship over time by analysing four distinct periods in 2020. STUDY DESIGN AND METHODS: This retrospective observational ecological study included individuals residing in the Primary Healthcare Cluster areas of Almada-Seixal and Western Lisbon and Oeiras, who tested positive for SARS-CoV-2 through a polymerase chain reaction (PCR) test between the 2nd of March and the 8th of November of 2020. Using incidence rates for each specific neighbourhood (n = 29) and period, we explored the relationship between neighbourhood-level socio-economic variables and the risk of infection using negative-binomial regression models. RESULTS: In the analysed period, a total of 8562 confirmed COVID-19 cases were identified. Overall incidence rates for each period were sequentially 2.74, 5.03, 3.99 and 14.29 COVID-19 cases per 100,000 person-days. Housing overcrowding, illiteracy rate and place of birth were associated with increased risk of infection, while age, congregate living, and employment in the secondary sector exhibited the opposite association. No association was consistent across all time periods. CONCLUSIONS: Our findings support the idea that the influence of socio-economic determinants of health is not immutable throughout time. In a pandemic context where information, knowledge, beliefs, and behaviours are ever-changing and evolving, a dynamic, inclusive, and adaptable approach to disease control can lead to a more equitable distribution of improved outcomes, benefiting all strata of society.


Subject(s)
COVID-19 , Humans , COVID-19/epidemiology , SARS-CoV-2 , Incidence , Pandemics , Retrospective Studies
2.
Poult Sci ; 102(1): 102270, 2023 Jan.
Article in English | MEDLINE | ID: mdl-36435166

ABSTRACT

Two trials were carried out to assess the effects of different ratios of standardized ileal digestible isoleucine:lysine (SID Ile:Lys) on the growth performance of broiler chickens fed low-protein diets. A total of 1,320 male chickens were distributed in each trial into 6 treatments, with 10 replicates with 22 birds each. A control diet was formulated that satisfied the nutritional requirements of the broilers, and a low-protein diet was formulated with reduced protein content, meeting broiler nutritional requirements, except for the SID Ile levels. Five SID Ile:Lys ratios (56%, 61%, 66%, 71%, and 76%) were obtained by adding l-isoleucine to the low-protein diet. The body weight (BW), body weight gain (BWG), average daily feed intake (ADFI), and feed conversion ratio (FCR) were evaluated from day 1 to day 21 in trial 1, and from day 22 to day 44 in trial 2. ANOVA was performed on the data, and the treatments were compared to the control group using Dunnett's test (P ≤ 0.05). Regression analyses were performed for modeling the variables assessed and the ratios of SID Ile:Lys. There was no significant difference between the treatments on ADFI of birds (P > 0.05). The BW, BWG, and FCR showed a quadratic effect as the SID Ile:Lys ratio increased in low-protein diets in trials 1 and 2 (P ≤ 0.05). In conclusion, the recommended ratio of SID Ile:Lys in low-protein diets for growth performance is around 66% for broiler chickens from 1 to 21 d old and is around 65% for broiler chickens from 22 to 44 d old.


Subject(s)
Isoleucine , Lysine , Animals , Male , Lysine/metabolism , Diet, Protein-Restricted/veterinary , Chickens/metabolism , Digestion , Diet/veterinary , Body Weight , Weight Gain , Animal Feed/analysis , Animal Nutritional Physiological Phenomena
3.
Radiologia (Engl Ed) ; 64(5): 397-406, 2022.
Article in English | MEDLINE | ID: mdl-36243439

ABSTRACT

INTRODUCTION AND AIMS: Contradictory results have been reported about hyperintensity of the globus pallidus and/or dentate nucleus on unenhanced T1-weighted magnetic resonance (MR) images after exposure to various gadolinium-based contrast agents. This change in signal intensity varies with different gadolinium-based contrast agents. We aimed to determine whether signal intensity in the dentate nucleus is increased in unenhanced T1-weighted images in patients who have undergone multiple studies with the macrocyclic gadolinium-based contrast agent gadoterate meglumine. We thoroughly reviewed the literature to corroborate our results. MATERIALS AND METHODS: We included patients who had undergone more than 10 MR studies with gadoterate meglumine. We quantitatively analyzed the signal intensity in unenhanced T1-weighted MR images measured in regions of interest placed in the dentate nucleus and the pons, and we calculated the dentate nucleus-to-pons signal intensity ratios and the differences between the ratio in the first MR study and the last MR study. We used t-tests to evaluate whether the differences between the signal intensity ratios were different from 0. We also analyzed the subgroups of patients who had been administered <15 and ≥15 doses of gadoterate meglumine. We used Pearson correlation to determine the relationships between the differences in the signal intensity ratios and the number of doses of gadoterate meglumine administered. RESULTS: The 54 patients (26 men) had received a mean of 13.8±3.47 doses (range, 10-23 doses). The difference in the dentate nucleus-pons signal intensity ratio between the first and last MR study was -0.0275±0.1917 (not significantly different from 0; p=0.2968) in the entire group, -0.0357±0.2204 (not significantly different from 0; p = 0.351 in the patients who had received <15 doses (n=34), and -0.0135±0.1332 (not significantly different from 0; p = 0.655) in those who had received ≥15 doses (n=20). Differences in signal intensity ratios did not correlate significantly with the accumulated dose of gadoterate meglumine (P = 0.9064; ρ = -0.0164 [95%]). CONCLUSIONS: Receiving more than 10 doses of gadoterate meglumine was not associated with increased signal intensity in the dentate nucleus.


Subject(s)
Contrast Media , Gadolinium , Cerebellar Nuclei/diagnostic imaging , Cerebellar Nuclei/pathology , Heterocyclic Compounds , Humans , Male , Meglumine , Organometallic Compounds , Retrospective Studies
4.
Poult Sci ; 101(11): 102148, 2022 Nov.
Article in English | MEDLINE | ID: mdl-36152435

ABSTRACT

Two trials were carried out to assess the effects of arginine supplementation through ratios of digestible arginine:lysine on growth performance, skin quality and creatine levels in muscle and serum of broiler chickens fed diets reduced in protein content. A total of 1,540 Cobb500 male chickens were distributed into 7 treatments, with 10 replicates with 22 birds each. The experimental diets were based on corn and soybean meal, and a control diet was formulated to satisfy broiler nutritional requirements. A basal diet with reduced protein content was formulated to meet broiler nutritional requirements, except for SID Arg levels. The experimental diets were obtained by adding L-arginine to basal diets, meeting 6 different SID Arg:Lys ratios (94, 100, 106, 112, 118, and 124%). Body weight, body weight gain, average daily feed intake, and feed conversion ratio were evaluated from 01 to 21 d old (trial 1) and from 22 to 44 d old (trial 2). At 21 and 44 d, in trials 1 and 2, respectively, birds were slaughtered to assess skin thickness (ST), skin strength (SS), creatine level in muscle (CRM) and serum (CRS). Data were subjected to ANOVA, and treatments were compared to the control group by Dunnett's test (P ≤ 0.05). Regression analyses were performed to model the variables assessed and the ratios of SID Arg:Lys. The SID Arg:Lys ratios did not affect ADFI of broilers in both trials (P > 0.05), whereas it linearly increased the BW, BWG, and ST, in both trials (P < 0.001). The FCR of broilers linearly decreased, in trial 1 (P = 0.038) and trial 2 (P < 0.001). The CRM of birds had a linear effect (P < 0.001) in trial 1, and a quadratic effect (P = 0.001) in trial 2. The CRS and SS of broilers linearly increased, in trial 2 (P < 0.001). In conclusion, increasing SID Arg:Lys ratios in diets reduced CP enhanced growth performance, skin quality and CR levels in muscle and serum of broiler chickens from 01 to 21 and 22 to 44 d old.


Subject(s)
Chickens , Animals , Male , Animal Feed/analysis , Animal Nutritional Physiological Phenomena , Arginine/metabolism , Body Weight , Chickens/physiology , Creatine/metabolism , Diet/veterinary , Dietary Supplements/analysis , Lysine/metabolism , Proteins/metabolism
5.
Radiología (Madr., Ed. impr.) ; 64(5): 397-406, Sep.-Oct. 2022. ilus, tab, graf
Article in Spanish | IBECS | ID: ibc-209915

ABSTRACT

Introducción y objetivo: Se han notificado resultados contradictorios sobre un aumento en la intensidad de la señal (IS) en las imágenes de resonancia magnética (RM) ponderadas en T1 no realzadas en el globo pálido y/o el núcleo dentado (ND) después de la exposición a varios agentes de contraste con gadolinio (ACG). Este cambio en la señal varía en función del ACG específico. Nuestro objetivo fue investigar si existe un aumento en la IS del ND en imágenes ponderadas en T1 no realzadas en pacientes sometidos a múltiples administraciones del ACG macrocíclico gadoterato de meglumina. Se realizó una revisión exhaustiva de la bibliografía para corroborar nuestros resultados. Materiales y métodos: Se incluyeron pacientes que se habían sometido a más de 10 estudios de RM con contraste y administración exclusiva de gadoterato de meglumina. Se llevó a cabo un análisis cuantitativo mediante el uso de mediciones de regiones de interés en el ND y el puente en imágenes no realzadas ponderadas en T1. Se calcularon las proporciones ND-puente y las diferencias en las proporciones entre el inicio y la última RM realizada. Se utilizó una prueba de la t de una muestra para evaluar si las diferencias en la proporción de la IS difieren de 0. Se realizó un análisis de subgrupos de pacientes con<15 y ≥15 dosis. Se utilizó el análisis de correlación de Pearson para determinar las correlaciones entre las diferencias de las proporciones de la IS y el número de administraciones del ACG.(AU)


Introduction and aims: Contradictory results have been reported about hyperintensity of the globus pallidus and/or dentate nucleus on unenhanced T1-weighted magnetic resonance (MR) images after exposure to various gadolinium-based contrast agents. This change in signal intensity varies with different gadolinium-based contrast agents. We aimed to determine whether signal intensity in the dentate nucleus is increased in unenhanced T1-weighted images in patients who have undergone multiple studies with the macrocyclic gadolinium-based contrast agent gadoterate meglumine. We thoroughly reviewed the literature to corroborate our results. Materials and methods: We included patients who had undergone more than 10 MR studies with gadoterate meglumine. We quantitatively analyzed the signal intensity in unenhanced T1-weighted MR images measured in regions of interest placed in the dentate nucleus and the pons, and we calculated the dentate nucleus-to-pons signal intensity ratios and the differences between the ratio in the first MR study and the last MR study. We used t-tests to evaluate whether the differences between the signal intensity ratios were different from 0. We also analyzed the subgroups of patients who had been administered<15 and ≥15 doses of gadoterate meglumine. We used Pearson correlation to determine the relationships between the differences in the signal intensity ratios and the number of doses of gadoterate meglumine administered.(AU)


Subject(s)
Humans , Male , Female , Cerebellar Nuclei , Gadolinium , Magnetic Resonance Spectroscopy , Globus Pallidus , Contrast Media , Radiology , Radiology Department, Hospital , Spain , 28599
6.
Radiologia (Engl Ed) ; 2020 Oct 05.
Article in English, Spanish | MEDLINE | ID: mdl-33032813

ABSTRACT

INTRODUCTION AND AIMS: Contradictory results have been reported about hyperintensity of the globus pallidus and/or dentate nucleus on unenhanced T1-weighted magnetic resonance (MR) images after exposure to various gadolinium-based contrast agents. This change in signal intensity varies with different gadolinium-based contrast agents. We aimed to determine whether signal intensity in the dentate nucleus is increased in unenhanced T1-weighted images in patients who have undergone multiple studies with the macrocyclic gadolinium-based contrast agent gadoterate meglumine. We thoroughly reviewed the literature to corroborate our results. MATERIALS AND METHODS: We included patients who had undergone more than 10 MR studies with gadoterate meglumine. We quantitatively analyzed the signal intensity in unenhanced T1-weighted MR images measured in regions of interest placed in the dentate nucleus and the pons, and we calculated the dentate nucleus-to-pons signal intensity ratios and the differences between the ratio in the first MR study and the last MR study. We used t-tests to evaluate whether the differences between the signal intensity ratios were different from 0. We also analyzed the subgroups of patients who had been administered<15 and ≥15 doses of gadoterate meglumine. We used Pearson correlation to determine the relationships between the differences in the signal intensity ratios and the number of doses of gadoterate meglumine administered. RESULTS: The 54 patients (26 men) had received a mean of 13.8±3.47 doses (range, 10-23 doses). The difference in the dentate nucleus-pons signal intensity ratio between the first and last MR study was -0.0275±0.1917 (not significantly different from 0; p=0.2968) in the entire group, -0.0357±0.2204 (not significantly different from 0; p=0.351 in the patients who had received <15 doses (n=34), and -0.0135±0.1332 (not significantly different from 0; p=0.655) in those who had received ≥15 doses (n=20). Differences in signal intensity ratios did not correlate significantly with the accumulated dose of gadoterate meglumine (P=0.9064; ρ=-0.0164 [95%]). CONCLUSIONS: Receiving more than 10 doses of gadoterate meglumine was not associated with increased signal intensity in the dentate nucleus.

7.
Int Urol Nephrol ; 51(10): 1823-1829, 2019 Oct.
Article in English | MEDLINE | ID: mdl-31368056

ABSTRACT

PURPOSE: The recent observation that urinary calcium excretion (UCE) drops considerably with CKD and that this effect may occur beyond compensation for reduced intestinal calcium absorption suggests that CKD per se is a state of sustained positive calcium balance, a mechanism likely to contribute to vascular calcification and CVD in CKD. However, the determinants of UCE reduction in CKD are not well understood and there is a lack of clinical studies, particularly in the CKD population. Therefore, in this study, we aimed to evaluate variables associated with UCE in a CKD cohort. METHODS: Baseline data on 356 participants of the Progredir Study, Sao Paulo, Brazil, essentially composed of CKD G3a-G4, were analyzed according to UCE (24 h urine collection). RESULTS: Median 24 h UCE was 38 mg/day (IQR 21-68 mg/day) and 0.48 mg/kg/day (IQR 0.28-0.82 mg/kg/day). In univariate analysis, UCE was inversely related to age, phosphorus, 1-84 PTH, FGF-23 and sclerostin, and positively associated with eGFR, DBP, 1,25(OH)2-vitamin D, calcium, bicarbonate, total calorie intake and spironolactone use. After adjustments for age, sex and eGFR, only 1,25(OH)2-vitamin D, calcium, FGF-23, bicarbonate and total calorie intake remained associated with it, but not PTH nor sclerostin. Lastly, in a multivariable model, eGFR, serum 1,25(OH)2-vitamin D, calcium, and FGF-23 remained associated with UCE. Similar results were observed when calcium fractional excretion was used instead of UCE, with eGFR, 1-25-vitamin D and FGF-23 remaining as independent associations. CONCLUSION: Our results showed that CKD is associated with very low levels of UCE and that 1,25(OH)2-vitamin D, serum calcium and FGF-23 were independently associated with UCE in this population, raising the question whether these factors are modulators of the tubular handling of calcium in CKD.


Subject(s)
Adaptor Proteins, Signal Transducing/physiology , Calcitriol/physiology , Fibroblast Growth Factors/physiology , Hypercalciuria/etiology , Parathyroid Hormone/physiology , Renal Insufficiency, Chronic/complications , Aged , Cross-Sectional Studies , Female , Fibroblast Growth Factor-23 , Humans , Male
8.
Bone ; 116: 215-220, 2018 11.
Article in English | MEDLINE | ID: mdl-30098418

ABSTRACT

The trabecular bone score (TBS) is a novel tool using grayscale variograms of the lumbar spine bone mineral density (BMD) to assess trabecular bone microarchitecture. Studies in patients with chronic kidney disease (CKD) suggest it may be helpful in assessing fracture risk. However, TBS has not been validated as a measure of trabecular architecture against transiliac bone biopsy with histomorphometry in CKD patients. We hypothesized that TBS would reflect trabecular architecture at the iliac crest in CKD patients. We obtained tetracycline double labeled transiliac crest bone biopsy, areal BMD of the spine, total hip, femoral neck (FN) and spine TBS by dual energy X-ray absorptiometry (DXA), and cortical and trabecular volumetric density and microarchitecture by high resolution peripheral quantitative computed tomography (HR-pQCT) in CKD patients from two centers: twenty-two patients from Columbia University Medical Center, USA and thirty patients from Hospital das Clinicas - Universidade de São Paulo, Brazil. Two patients were excluded for outlier status. Univariate and multivariate relationships between TBS and measures from DXA, HR-pQCT and histomorphometry were determined. Patients were 50.2 ±â€¯15.8 years old, 23 (46%) were men, and 33 (66%) were on dialysis. TBS was <1.31 in 21 (42%) patients and 22%, 14% and 10% had T-scores ≤ -2.5 at spine, FN and total hip respectively. In univariate regression, TBS was significantly associated with trabecular bone volume (BV/TV), trabecular width (Tb.Wi), trabecular spacing, cortical width but not with trabecular number or cortical porosity. FN Z-score and height were also associated with cancellous BV/TV and Tb.Wi, In multivariate analysis, TBS remained an independent predictor of BV/TV and Tb.Wi. There were no relationships between TBS and dynamic parameters from histomorphometry. These data suggest that TBS reflected trabecular microarchitecture and cortical width measured by bone biopsy in CKD patients. Future studies should address its utility in the identification of CKD patients who may benefit from fracture prevention strategies.


Subject(s)
Absorptiometry, Photon , Cancellous Bone/diagnostic imaging , Cancellous Bone/pathology , Cortical Bone/diagnostic imaging , Cortical Bone/pathology , Renal Insufficiency, Chronic/diagnostic imaging , Female , Humans , Linear Models , Male , Middle Aged , Multivariate Analysis , Renal Insufficiency, Chronic/pathology , Statistics, Nonparametric
9.
J Hazard Mater ; 323(Pt A): 575-583, 2017 Feb 05.
Article in English | MEDLINE | ID: mdl-27329790

ABSTRACT

Pharmaceutical residues presence in the environment is among nowadays top emergent environmental issues. For removal of such pollutants, adsorption is a generally efficient process that can be complementary to conventional treatment. Research of cheap, widely available adsorbents may make this process economically attractive. The aim of the present work was to evaluate the capacity of two clay materials (exfoliated vermiculite, LECA) to adsorb gemfibrozil, mefenamic acid and naproxen in lab-scale batch assays. Results show that both adsorbents are able to remove the pharmaceuticals from aqueous medium. Although vermiculite exhibited higher adsorption capacities per unit mass of adsorbent, LECA yielded higher absolute removals of the pharmaceuticals due to the larger mass of adsorbent. Quantum chemistry calculations predicted that the forms of binding of the three molecules to the vermiculite surface are essentially identical, but the adsorption isotherm of naproxen differs substantially from the other two's. The linear forms of the latter impose limits at lower concentrations to the removal efficiencies of these pharmaceuticals by vermiculite, thereby electing LECA as more efficient. Notwithstanding, vermiculite's high specific adsorption capacity and also its much faster adsorption kinetics suggest that there may be some benefits in combining both materials as a composite adsorbent solution.


Subject(s)
Aluminum Silicates/chemistry , Pharmaceutical Preparations/isolation & purification , Adsorption , Clay , Computer Simulation , Drug Residues/isolation & purification , Gemfibrozil/chemistry , Gemfibrozil/isolation & purification , Kinetics , Mefenamic Acid/chemistry , Mefenamic Acid/isolation & purification , Models, Molecular , Naproxen/chemistry , Naproxen/isolation & purification , Particle Size , Thermodynamics , Waste Disposal, Fluid
10.
Biochim Biophys Acta ; 1858(11): 2647-2661, 2016 Nov.
Article in English | MEDLINE | ID: mdl-27475296

ABSTRACT

Fluorescence spectroscopy and microscopy have been utilized as tools in membrane biophysics for decades now. Because phospholipids are non-fluorescent, the use of extrinsic membrane probes in this context is commonplace. Among the latter, 1,6-diphenylhexatriene (DPH) and its trimethylammonium derivative (TMA-DPH) have been extensively used. It is widely believed that, owing to its additional charged group, TMA-DPH is anchored at the lipid/water interface and reports on a bilayer region that is distinct from that of the hydrophobic DPH. In this study, we employ atomistic MD simulations to characterize the behavior of DPH and TMA-DPH in 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and POPC/cholesterol (4:1) bilayers. We show that although the dynamics of TMA-DPH in these membranes is noticeably more hindered than that of DPH, the location of the average fluorophore of TMA-DPH is only ~3-4Å more shallow than that of DPH. The hindrance observed in the translational and rotational motions of TMA-DPH compared to DPH is mainly not due to significant differences in depth, but to the favorable electrostatic interactions of the former with electronegative lipid atoms instead. By revealing detailed insights on the behavior of these two probes, our results are useful both in the interpretation of past work and in the planning of future experiments using them as membrane reporters.


Subject(s)
Cholesterol/chemistry , Diphenylhexatriene/analogs & derivatives , Diphenylhexatriene/chemistry , Fluorescent Dyes/chemistry , Molecular Dynamics Simulation , Phosphatidylcholines/chemistry , Fluorescence , Fluorescence Polarization , Hydrophobic and Hydrophilic Interactions , Lipid Bilayers/chemistry , Membrane Fluidity , Static Electricity , Thermodynamics , Water/chemistry
11.
AJNR Am J Neuroradiol ; 37(8): 1427-31, 2016 Aug.
Article in English | MEDLINE | ID: mdl-27032972

ABSTRACT

BACKGROUND AND PURPOSE: Different T1-weighted sequences have been used for qualitative and quantitative evaluation of T1 signal intensity related to gadolinium deposition in the dentate nucleus in patients who underwent several enhanced MR imaging studies. Our purpose was to perform an intraindividual qualitative and quantitative comparison between T1-weighted spin-echo and 3D magnetization-prepared rapid acquisition of gradient echo sequences in patients who had multiple exposures to gadodiamide. MATERIALS AND METHODS: Our retrospectively selected population included 18 patients who underwent at least 3 administrations of gadodiamide and had a baseline and a final MR imaging performed with both T1-weighted sequences. Qualitative and quantitative analyses were independently performed. Dentate nucleus/middle cerebellar peduncle signal-intensity ratios and signal changes between the baseline and final examinations were compared by using the Wilcoxon signed rank test. Correlation between quantitative and qualitative evaluations was assessed by using a polyserial correlation test. RESULTS: The differences between the 2 sequences for both baseline and last examination dentate nucleus/middle cerebellar peduncle ratios were statistically significant (P = .008 and P = .006, respectively); however, the signal-intensity changes of the ratios with time were not (P = .64). The correlation between the qualitative and quantitative analysis was very strong (near-perfect) (r = 0.9) for MPRAGE and strong (r = 0.63) for spin-echo sequences. CONCLUSIONS: T1-weighted spin-echo and MPRAGE sequences cannot be used interchangeably for qualitative or quantitative analysis of signal intensity in the dentate nucleus in patients who received gadodiamide. Baseline and final examination ratios should be evaluated across time by using the same sequence. Qualitative analysis performed with MPRAGE correlated better with quantitative analysis and may offer advantages over spin-echo sequences for research purposes.


Subject(s)
Cerebellar Nuclei/diagnostic imaging , Contrast Media , Gadolinium DTPA , Image Interpretation, Computer-Assisted/methods , Magnetic Resonance Imaging/methods , Adult , Aged , Female , Humans , Male , Middle Aged , Retrospective Studies
12.
AJNR Am J Neuroradiol ; 37(5): E42, 2016 05.
Article in English | MEDLINE | ID: mdl-26915565
13.
Phys Chem Chem Phys ; 18(10): 7042-54, 2016 Mar 14.
Article in English | MEDLINE | ID: mdl-26727975

ABSTRACT

Nitrobenzoxadiazole (NBD)-labeled lipids are popular fluorescent membrane probes. However, the understanding of important aspects of the photophysics of NBD remains incomplete, including the observed shift in the emission spectrum of NBD-lipids to longer wavelengths following excitation at the red edge of the absorption spectrum (red-edge excitation shift or REES). REES of NBD-lipids in membrane environments has been previously interpreted as reflecting restricted mobility of solvent surrounding the fluorophore. However, this requires a large change in the dipole moment (Δµ) of NBD upon excitation. Previous calculations of the value of Δµ of NBD in the literature have been carried out using outdated semi-empirical methods, leading to conflicting values. Using up-to-date density functional theory methods, we recalculated the value of Δµ and verified that it is rather small (∼2 D). Fluorescence measurements confirmed that the value of REES is ∼16 nm for 1,2-dioleoyl-sn-glycero-3-phospho-l-serine-N-(NBD) (NBD-PS) in dioleoylphosphatidylcholine vesicles. However, the observed shift is independent of both the temperature and the presence of cholesterol and is therefore insensitive to the mobility and hydration of the membrane. Moreover, red-edge excitation leads to an increased contribution of the decay component with a shorter lifetime, whereas time-resolved emission spectra of NBD-PS displayed an atypical blue shift following excitation. This excludes restrictions to solvent relaxation as the cause of the measured REES and TRES of NBD, pointing instead to the heterogeneous transverse location of probes as the origin of these effects. The latter hypothesis was confirmed by molecular dynamics simulations, from which the calculated heterogeneity of the hydration and location of NBD correlated with the measured fluorescence lifetimes/REES. Globally, our combination of theoretical and experiment-based techniques has led to a considerably improved understanding of the photophysics of NBD and a reinterpretation of its REES in particular.


Subject(s)
Benzoxazoles/chemistry , Fluorescent Dyes/chemistry , Lipids/chemistry , Fluorescence , Molecular Dynamics Simulation , Quantum Theory , Spectrometry, Fluorescence
14.
AJNR Am J Neuroradiol ; 37(7): 1192-8, 2016 Jul.
Article in English | MEDLINE | ID: mdl-26659341

ABSTRACT

In current practice, gadolinium-based contrast agents have been considered safe when used at clinically recommended doses in patients without severe renal insufficiency. The causal relationship between gadolinium-based contrast agents and nephrogenic systemic fibrosis in patients with renal insufficiency resulted in new policies regarding the administration of these agents. After an effective screening of patients with renal disease by performing either unenhanced or reduced-dose-enhanced studies in these patients and by using the most stable contrast agents, nephrogenic systemic fibrosis has been largely eliminated since 2009. Evidence of in vivo gadolinium deposition in bone tissue in patients with normal renal function is well-established, but recent literature showing that gadolinium might also deposit in the brain in patients with intact blood-brain barriers caught many individuals in the imaging community by surprise. The purpose of this review was to summarize the literature on gadolinium-based contrast agents, tying together information on agent stability and animal and human studies, and to emphasize that low-stability agents are the ones most often associated with brain deposition.


Subject(s)
Contrast Media/adverse effects , Contrast Media/pharmacokinetics , Gadolinium/adverse effects , Gadolinium/pharmacokinetics , Nephrogenic Fibrosing Dermopathy/chemically induced , Animals , Cerebellar Nuclei/diagnostic imaging , Humans , Magnetic Resonance Imaging/adverse effects , Nephrogenic Fibrosing Dermopathy/epidemiology
15.
Phys Chem Chem Phys ; 17(35): 22736-48, 2015 Sep 21.
Article in English | MEDLINE | ID: mdl-26255832

ABSTRACT

Following a recent experimental investigation of the effect of the length of the alkyl side chain in a series of cholesterol analogues (Angew. Chem., Int. Ed., 2013, 52, 12848-12851), we report here an atomistic molecular dynamics characterization of the behaviour of methyl-branched side chain sterols (iso series) in POPC bilayers. The studied sterols included androstenol (i-C0-sterol) and cholesterol (i-C8-sterol), as well as four other derivatives (i-C5, i-C10, i-C12 and i-C14-sterol). For each sterol, both subtle local effects and more substantial differential alterations of membrane properties along the iso series were investigated. The location and orientation of the tetracyclic ring system is almost identical in all compounds. Among all the studied sterols, cholesterol is the sterol that presents the best matching with the hydrophobic length of POPC acyl chains, whereas longer-chained sterols interdigitate into the opposing membrane leaflet. In accordance with the experimental observations, a maximal ordering effect is observed for intermediate sterol chain length (i-C5, cholesterol, i-C10). Only for these sterols a preferential interaction with the saturated sn-1 chain of POPC (compared to the unsaturated sn-2 chain) was observed, but not for either shorter or longer-chained derivatives. This work highlights the importance of the sterol alkyl chain in the modulation of membrane properties and lateral organization in biological membranes.


Subject(s)
Lipid Bilayers/chemistry , Molecular Dynamics Simulation , Phosphatidylcholines/chemistry , Sterols/chemistry , Molecular Conformation
16.
Braz J Biol ; 75(2): 414-22, 2015 May.
Article in English | MEDLINE | ID: mdl-26132026

ABSTRACT

AIMS: The present study verified the effect of propolis alone and its association with swimming in dyslipidemia, left ventricular hypertrophy and atherogenesis of hypercholesterolemic mice. METHODS AND RESULTS: The experiments were performed in LDLr-/- mice, fed with high fat diet for 75 days, and were divided into four experimental groups (n=10): HL, sedentary, subjected to aquatic stress (5 min per day, 5 times per week); NAT submitted to a swimming protocol (1 hour per day, 5 times per week) from the 16th day of the experiment; PRO, sedentary, submitted to aquatic stress and which received oral propolis extract (70 uL/animal/day) from the 16th day of the experiment; HL+NAT+PRO, submitted to swimming and which received propolis as described above. After 75 days, blood was collected for analysis of serum lipids. The ratio between the ventricular weight (mg) and the animal weight (g) was calculated. Histological sections of the heart and aorta were processed immunohistochemically with anti-CD40L antibodies to evaluate the inflammatory process; stained with hematoxylin/eosin and picrosirius red to assess morphological and morphometric alterations. The HL animals showed severe dyslipidemia, atherogenesis and left ventricular hypertrophy, associated with a decrease in serum HDLc levels and subsequent development of cardiovascular inflammatory process, characterized by increased expression of CD40L in the left ventricle and aorta. Swimming and propolis alone and\or associated prevented the LVH, atherogenesis and arterial and ventricular inflammation, decreasing the CD40L expression and increasing the HDLc plasmatic levels. CONCLUSION: Propolis alone or associated with a regular physical activity is beneficial in cardiovascular protection through anti-inflammatory action.


Subject(s)
Atherosclerosis/prevention & control , Hypercholesterolemia/complications , Hypertrophy, Left Ventricular/prevention & control , Physical Conditioning, Animal , Propolis/administration & dosage , Swimming , Animals , Atherosclerosis/etiology , Hypertrophy, Left Ventricular/etiology , Male , Mice , Mice, Inbred C57BL
17.
Phys Chem Chem Phys ; 17(31): 20066-79, 2015 Aug 21.
Article in English | MEDLINE | ID: mdl-26063509

ABSTRACT

A complete homologous series of fluorescent phosphatidylethanolamines (diCnPE), labelled at the head group with a 7-nitrobenz-2-oxa-1,3-diazo-4-yl(NBD) fluorophore and inserted in 1-palmitoyl, 2-oleoyl-sn-glycero-3-phosphocholine (POPC) bilayers, was studied using atomistic molecular dynamics simulations. The longer-chained derivatives of NBD-diCnPE, with n = 14, 16, and 18, are commercially available, and widely used as fluorescent membrane probes. Properties such as location of atomic groups and acyl chain order parameters of both POPC and NBD-diCnPE, fluorophore orientation and hydrogen bonding, membrane electrostatic potential and lateral diffusion were calculated for all derivatives in the series. Most of these probes induce local disordering of POPC acyl chains, which is on the whole counterbalanced by ordering resulting from binding of sodium ions to lipid carbonyl/glycerol oxygen atoms. An exception is found for NBD-diC16PE, which displays optimal matching with POPC acyl chain length and induces a slight local ordering of phospholipid acyl chains. Compared to previously studied fatty amines, acyl chain-labelled phosphatidylcholines, and sterols bearing the same fluorescent tag, the chromophore in NBD-diCnPE locates in a similar region of the membrane (near the glycerol backbone/carbonyl region) but adopts a different orientation (with the NO2 group facing the interior of the bilayer). This modification leads to an inverted orientation of the P-N axis in the labelled lipid, which affects the interface properties, such as the membrane electrostatic potential and hydrogen bonding to lipid head group atoms. The implications of this study for the interpretation of the photophysical properties of NBD-diCnPE (complex fluorescence emission kinetics, differences with other NBD lipid probes) are discussed.


Subject(s)
Azoles/chemistry , Lipid Bilayers/chemistry , Molecular Dynamics Simulation , Nitrobenzenes/chemistry , Phosphatidylcholines/chemistry , Phosphatidylethanolamines/chemistry , Hydrogen Bonding , Molecular Conformation , Static Electricity
18.
AJNR Am J Neuroradiol ; 36(6): 1039-42, 2015 Jun.
Article in English | MEDLINE | ID: mdl-25678481

ABSTRACT

BACKGROUND AND PURPOSE: Because evidence-based articles are difficult to recognize among the large volume of publications available, some journals have adopted evidence-based medicine criteria to classify their articles. Our purpose was to determine whether an evidence-based medicine classification used by a subspecialty-imaging journal allowed consistent categorization of levels of evidence among different raters. MATERIALS AND METHODS: One hundred consecutive articles in the American Journal of Neuroradiology were classified as to their level of evidence by the 2 original manuscript reviewers, and their interobserver agreement was calculated. After publication, abstracts and titles were reprinted and independently ranked by 3 different radiologists at 2 different time points. Interobserver and intraobserver agreement was calculated for these radiologists. RESULTS: The interobserver agreement between the original manuscript reviewers was -0.2283 (standard error = 0.0000; 95% CI, -0.2283 to -0.2283); among the 3 postpublication reviewers for the first evaluation, it was 0.1899 (standard error = 0.0383; 95% CI, 0.1149-0.2649); and for the second evaluation, performed 3 months later, it was 0.1145 (standard error = 0.0350; 95% CI, 0.0460-0.1831). The intraobserver agreement was 0.2344 (standard error = 0.0660; 95% CI, 0.1050-0.3639), 0.3826 (standard error = 0.0738; 95% CI, 0.2379-0.5272), and 0.6611 (standard error = 0.0656; 95% CI, 0.5325-0.7898) for the 3 postpublication evaluators, respectively. These results show no-to-fair interreviewer agreement and a tendency to slight intrareviewer agreement. CONCLUSIONS: Inconsistent use of evidence-based criteria by different raters limits their utility when attempting to classify neuroradiology-related articles.


Subject(s)
Evidence-Based Medicine/classification , Periodicals as Topic/standards , Humans , Observer Variation
19.
J Mol Model ; 20(7): 2336, 2014 Jul.
Article in English | MEDLINE | ID: mdl-25069137

ABSTRACT

Widespread use of pharmaceuticals such as benzodiazepines has been resulting over the last decades in the dissemination of residues of these compounds in the environment, and such fact has been raising increasing concern. The generally low efficiencies of conventional wastewater treatment processes for the removal of this type of pollutants demands for the development of alternative or complementary water and wastewater treatment technologies, among which adsorption processes have been gaining popularity, provided that cheap efficient adsorbents are found. Clay materials have been one of the popular choices in this regard. In the present study, quantum chemical calculations have been performed by periodic DFT using the projector augmented-wave (PAW) method to characterize the interactions of two benzodiazepine molecules, alprazolam and diazepam, with a surface of clay mineral, vermiculite. It was observed that both molecules interact strongly with the vermiculite surface, both through a water-bridge binding and by cation-bridge provided by the exchangeable Mg(2+) cations of the vermiculite surface. The results point to an interesting potential of vermiculite to be used efficiently as filter medium to remove these pollutants from water and wastewater.

20.
Transpl Infect Dis ; 16(2): 315-9, 2014 Apr.
Article in English | MEDLINE | ID: mdl-24621124

ABSTRACT

Pneumocystis jirovecii pneumonia (PCP) continues to be a leading cause of morbidity and mortality in kidney transplant recipients. Granulomatous PCP is an unusual histological presentation that has been described in a variety of immunosuppressive conditions. Previous studies have demonstrated an association between granulomatous disorders and hypercalcemia, the purported mechanism of which is extrarenal production of 1,25-dihydroxyvitamin D by activated macrophages. Here, we report a case of granulomatous formation in a kidney transplant recipient with PCP who presented with hypercalcemia and suppressed parathyroid hormone, both of which resolved after successful treatment of the pneumonia. In immunocompromised patients, pulmonary infection associated with hypercalcemia should raise the suspicion of PCP and other granulomatous disorders.


Subject(s)
Granuloma/microbiology , Kidney Transplantation/adverse effects , Pneumonia, Pneumocystis/microbiology , Female , Granuloma/pathology , Humans , Hypercalcemia/etiology , Male , Middle Aged , Pneumocystis carinii
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