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Structural and dynamical properties of Sr2+ and Ba2+ dications in ammonia microsolvation environments were studied through hybrid density functional theory Born-Oppenhemier molecular dynamics of [Sr(NH3)n]2+ and [Ba(NH3)n]2+ clusters with n = 2, 3, 4, 5, 6, 8, 10, and 27. The largest cluster models were used to explore bulk phase solvation of Sr2+ and Ba2+ in liquid ammonia for which experimental data are available. Results are discussed in the light of previous results obtained for the [Mg(NH3)n]2+ and [Ca(NH3)n]2+ systems with the same methodology. Vibrational and EXAFS spectra are reported for the first time for [Sr(NH3)n]2+ and [Ba(NH3)n]2+ systems. It was found that alkaline earth dications have coordination numbers (CN) in ammonia as follows: Mg2+ (6) < Ca2+ (8) < Sr2+ (8.3) < Ba2+ (9.4). The coordination structures found turn out to be rather flexible with CN greater than six and these structures depart from the simple geometry of hexamine in the solid phase.
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The increasing prevalence of fluconazole-resistant clinical isolates of Candida spp. strongly hinders the widespread use of the drug. To tackle this problem, great efforts have been made to fully understand the fungal response to fluconazole. In this work, we show that the role of Zap1 in Candida glabrata goes beyond regulating yeast adaptation to zinc deficiency. In line with our previous observation that deletion of ZAP1 makes yeast cells more sensitive to fluconazole, we found that the mutant CgΔzap1 accumulates higher levels of the drug, which correlates well with its lower levels of ergosterol. Surprisingly, Zap1 is a negative regulator of the drug efflux transporter gene CDR1 and of its regulator, PDR1. The apparent paradox of drug accumulation in cells where genes encoding transporters relevant for drug extrusion are being overexpressed led us to postulate that their activity could be impaired. In agreement, Zap1-depleted cells present, in addition to decreased ergosterol levels, an altered composition of membrane phospholipids, which together should impact membrane function and impair the detoxification of fluconazole. Overall, our study brings to light Zap1 as an important hub in Candida glabrata response to fluconazole.
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Candida glabrata , Fluconazol , Proteínas Fúngicas , Antifúngicos/farmacología , Candida , Candida glabrata/efectos de los fármacos , Candida glabrata/genética , Farmacorresistencia Fúngica , Ergosterol , Fluconazol/farmacología , Proteínas Fúngicas/genética , Proteínas Fúngicas/farmacología , Pruebas de Sensibilidad MicrobianaRESUMEN
We report the structural and energetic features of the Mg2+ and Ca2+ cations in ammonia microsolvation environments. Born-Oppenhemier molecular dynamics studies are carried out for [Mg(NH3)n]2+ and [Ca(NH3)n]2+ clusters with n = 2, 3, 4, 6, 8, 20, and 27 at 300 K based on hybrid density functional theory calculations. We determine binding energies per ammonia molecule and the metal cation solvation patterns as a function of the number of molecules. The general trend for Mg2+ is that the Mg-N distances increase as a function of n until the first solvation shell is populated by six ammonia molecules, and then the distances slightly decrease while CN = 6 does not change. For Ca2+, the first solvation shell at room temperature is populated by eight ammonia molecules for clusters with more than one solvation shell, leading to a different structure from that of [Ca(NH3)6]2+ hexamine. The evaporation of NH3 molecules was found at 300 K only for Mg2+ clusters with n ≥ 10; this was not the case for Ca2+ clusters. Vibrational spectra are obtained for all of the clusters, and the evolution of the main features is discussed. EXAFS spectra are also presented for the [Mg(NH3)27(NH3)27]2+ and [Ca(NH3)27]2+ clusters, which yield valuable data to be compared with experimental data in the liquid phase, as previously done for the aqueous solvation of these dications.
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Kelps are canopy-forming brown seaweed sustaining critical ecosystem services in coastal habitats, including shelter, nursery grounds, and providing food resources to a myriad of associated species. This study modeled the fundamental niche of Laminaria abyssalis along the Brazilian continental margin, an endemic species of the South Atlantic, to anticipate potential distributional range shifts under two contrasting scenarios of future environmental changes (RCP2.6 and RCP8.5). The model for fundamental niche predictions considering the "present scenario" has shown a wider potential area than the realized niche (i.e., the area where the species actually occurs) along the Brazilian coast. In both future scenarios, the models have shown niche erosion on the northern portion of the Brazilian coast and niche gains towards the south. In both scenarios, L. abyssalis populations tend to shift to deeper regions of the reef. The restricted range of occurrence (33,000 km2), intense anthropic activities along these beds (e.g., trawling fisheries, oil/gas mining, or removal for agricultural purposes) acting synergically with global warming, may drive this ecosystem to collapse faster than kelp species' ability to adapt. We propose to classify L. abyssalis as Endangered - (EN) under IUCN criteria, and highlight that long-term monitoring of kelp beds is an urgent need to develop effective conservation initiatives to protect such rare and invaluable ecosystem.
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Kelp , Brasil , Ecosistema , Explotaciones Pesqueras , Calentamiento GlobalRESUMEN
OBJECTIVE: This study aimed to investigate whether the occurrence of urinary incontinence (UI) is associated with increased odds of depression in perimenopausal and postmenopausal women. METHODS: This cross-sectional study included 208 women with depressive symptoms, confirmed by the Beck Depression Inventory, and 247 patients without depression. All participants were perimenopausal or postmenopausal women aged 35 to 65 years who attended an outpatient clinic from a tertiary-academic hospital in Northeastern Brazil. Urinary incontinence symptoms were assessed using patient's self-report and the validated versions of the International Consultation on Incontinence Questionnaire-Short Form and the Questionnaire for Urinary Incontinence Diagnosis. To investigate the severity of climacteric symptoms, the Blatt-Kupperman Index was used, and menopause-related quality of life was analyzed using the Utian Quality of Life Questionnaire. RESULTS: In univariate analysis, the Beck Depression Inventory-II mean scores for UI and non-UI women were, respectively, 15.5 (95% confidence interval, 14.28-16.72) and 11.83 (10.52-13.13; P < 0.05). Patients with moderate and severe scores of depression reported higher International Consultation on Incontinence Questionnaire-Short Form and Questionnaire for Urinary Incontinence Diagnosis scores when compared with women with mild depression scores and women without depression (P < 0.001). Conversely, in multivariate analysis, having UI was not associated with having depression (odds ratio [OR], 0.85; 0.52-1.37; P = 0.50), after adjusting for confounders. Older age (>55 years) was associated with decreased odds of depression (OR, 0.43; 0.21-0.88; P = 0.02), whereas moderate (OR, 2.28; 1.40-3.71; P = 0.001) and severe (OR, 7.70; 2.79-21.23) intensities of menopause symptoms were associated with increased odds of depression. CONCLUSION: Urinary incontinence was not associated with depression within climacteric women after multivariate analysis.
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Climaterio , Depresión/epidemiología , Incontinencia Urinaria/epidemiología , Adulto , Factores de Edad , Anciano , Estudios Transversales , Femenino , Humanos , Persona de Mediana Edad , Calidad de Vida , Índice de Severidad de la EnfermedadRESUMEN
Invasive fungal infections (IFIs) are life threatening and existing antifungal drugs are not completely effective due to undesirable side effects and resistance emergence. Azoles are often the treatment of choice for IFIs and growing evidence suggests that copper can act synergistically with these drugs. In this work, we designed a compound bringing together azole and copper(II)-binding groups and studied the molecular mechanisms underlying its biological toxicity. Our results show that both the compound, 4, and its copper(II) complex, Cu.4, are active against Candida spp. We found that Cu.4 acts as a copper(II) ionophore, which results in the intracellular accumulation of reactive oxygen species (ROS), whereas compound 4 is an iron chelator and exerts its toxicity by decreasing iron bioavailability. Interestingly, while 4 is not very toxic to macrophages or HeLa cells, Cu.4 significantly affects their viability. Overall, this work provides evidence of how copper can be combined with azoles to deregulate copper homeostasis, opening new horizons for the development of bifunctional antifungals.
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Antifúngicos/química , Antifúngicos/farmacología , Candida/efectos de los fármacos , Cobre/química , Ionóforos/química , Triazoles/química , Triazoles/farmacología , Antifúngicos/toxicidad , Supervivencia Celular/efectos de los fármacos , Células HeLa , Humanos , Triazoles/toxicidadRESUMEN
STUDY QUESTION: Do human granulosa cells (GCs) ingest and destroy apoptotic oocytes? SUMMARY ANSWER: Somatic GCs ingest and destroy apoptotic oocytes and other apoptotic substrates through unconventional autophagy-assisted phagocytosis. WHAT IS KNOWN ALREADY: Most (99%) ovarian germ cells undergo apoptosis through follicular atresia. The mode of cleaning of atretic follicles from the ovary is unclear. Ovarian GCs share striking similarities with testicular Sertoli cells with respect to their origin and function. Somatic Sertoli cells are responsible for the elimination of apoptotic spermatogenic cells through unconventional autophagy-assisted phagocytosis. STUDY DESIGN, SIZE, DURATION: Human GCs were tested for the ability to ingest and destroy the apoptotic oocytes and other apoptotic substrates. A systemic study of the main phagocytosis steps has been performed at different time points after loading of apoptotic substrates into the GC. PARTICIPANTS/MATERIALS, SETTING, METHODS: Primary cultures of GC retrieved following controlled ovarian stimulation of five women for IVF/ICSI and a human granulosa KGN cell line were incubated with different apoptotic substrates: oocytes which underwent spontaneous apoptosis during the cultivation of immature germ cells for IVF/ICSI; apoptotic KGN cells; and apoptotic membranes from rat retinas. Cultured GC were analyzed for the presence of specific molecular markers characteristic of different steps of phagocytic and autophagy machineries by immunocytochemistry, confocal microscopy, transmission electron microscopy and western blotting, before and after loading with apoptotic substrates. MAIN RESULTS AND THE ROLE OF CHANCE: Incubation of human GC with apoptotic substrates resulted in their translocation in cell cytoplasm, concomitant with activation of the phagocytosis receptor c-mer proto-oncogene tyrosine kinase MERTK (P < 0.001), clumping of motor molecule myosin II, recruitment of autophagy proteins: autophagy-related protein 5 (ATG5), autophagy-related protein 6 (Beclin1) and the rise of a membrane form of microtubule-associated protein 1 light chain 3 (LC3-II) protein. Ingestion of apoptotic substrates was accompanied by increased expression of the lysosomal protease Cathepsin D (P < 0.001), and a rise of lysosomes in the GCs, as assessed by different techniques. The level of autophagy adaptor, sequestosome 1/p62 (p62) protein remained unchanged. LARGE SCALE DATA: N/A. LIMITATIONS, REASONS FOR CAUTION: The number of patients described here is limited. Also the dependence of phagocytosis on reproductive hormone status of patients should be analyzed. WIDER IMPLICATIONS OF THE FINDINGS: Removal of apoptotic oocytes by surrounding GC seems likely to be a physiological mechanism involved in follicular atresia. Proper functioning of this mechanism may be a new strategy for the treatment of ovarian dysfunctions associated with an imbalance in content of germ cells in the ovaries, such as premature ovarian failure and polycystic ovary syndrome. STUDY FUNDING/COMPETING INTEREST(S): The study was funded by Rennes Metropole (AIS 2015) and Agence de BioMédecine. This work was supported by funding from Université de Rennes1, Institut National de la Santé et de la Recherche Médicale (INSERM) and CHU de Rennes. A.B. is funded in part by the program Actions Concertées Interpasteuriennes (ACIP) and a research grant from the European Society of Pediatric Endocrinology. This work is supported by the Agence Nationale de la Recherche Grants ANR-17-CE14-0038 and ANR-10-LABX-73. The authors declare no competing interests.
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Atresia Folicular , Células de la Granulosa , Animales , Autofagia , Femenino , Humanos , Masculino , Oocitos , Fagocitosis , Proto-Oncogenes Mas , RatasRESUMEN
The Pb2+ presents unique hydration features that make the experimental characterization and its theoretical modeling challenging: classical molecular dynamics (MD) with standard force-fields fails to produce the experimentally determined diffusion coefficient and the EXAFS spectrum. Here we study the hydration of Pb2+ in aqueous solution employing a polarizable model compatible with the MCDHO water model. The MCDHO FF for the Pb2+-water interaction was fitted to reproduce the configurations and interaction energies of various [Pb(H2O)n]2+ clusters obtained with ab initio calculations, with n = 4, 6, and 8. Its use in classical MD simulations yielded qualitative agreement with Born-Oppenheimer molecular dynamics of gas-phase hydrated clusters and MD simulations of the aqueous solution resulted in good agreement with the experimental DPb2+ and EXAFS spectrum. Analysis of the MD trajectories revealed a labile and very dynamic hemidirected first hydration shell in the aqueous solution with a non-well-defined coordination number CN; nonetheless, it was found that the more probable hydration structures have either 3 or 4 water molecules directly bound to the Pb2+ with another 3 or 2 at slightly larger distances. The simulations of the gas-phase [Pb(H2O)29]2+ cluster were found to capture the main structural features of the diluted aqueous solution.
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Systemic lupus erythematosus (SLE) is associated with several cardiac manifestations but, to our knowledge, there have been no previously published reports on left ventricular (LV) pseudoaneurysm in this disease. We describe a case of a 30-year-old woman with SLE who presented with a disease flare (acute and subacute cutaneous lupus, pericarditis, fever, leukopenia) associated with heart failure syndrome. The patient was diagnosed with a large LV pseudoaneurysm and a bovine pericardium patch closure was performed. Coronary arteries were angiographically normal, and cardiac magnetic resonance imaging did not exhibit detectable myocardial fibrosis or infarction. Trauma, previous cardiac surgery, Chagas disease, and antiphospholipid syndrome were excluded. Histopathology of the pericardium revealed lymphocytic arteriolitis raising the possibility of an autoimmune-mediated mechanism for this complication. The unequivocal concomitant diagnosis of lupus flare, the exclusion of other causes of pseudoaneurysm and the histopathological finding of arteriolitis in this patient reinforces the hypothesis of lupus-mediated lesion.
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Aneurisma Falso/diagnóstico por imagen , Aneurisma Falso/patología , Ventrículos Cardíacos/patología , Lupus Eritematoso Sistémico/complicaciones , Adulto , Aneurisma Falso/cirugía , Animales , Bovinos , Angiografía Coronaria , Femenino , Aneurisma Cardíaco/diagnóstico por imagen , Aneurisma Cardíaco/cirugía , Insuficiencia Cardíaca/etiología , Ventrículos Cardíacos/diagnóstico por imagen , Humanos , Imagen por Resonancia Magnética , Radiografía TorácicaRESUMEN
For more than a decade, the existence of ovarian stem cells that can contribute to neo-oogenesis in the adult ovary is reported by some teams, challenging the dogma according to which mammalian females are born with a fixed and non-renewed germinal cell pool. The presence of germinal stem cells with mitotic activity suggests the possibility of potential postnatal oogenesis. These cells have both germ-line and stem cell markers in culture. They have been isolated using different strategies and their ability to differentiate into oocytes has been demonstrated since after reintroduction in an ovarian somatic environment, these cells generate follicles capable of producing healthy offspring in rodents. However, many scientists remain skeptical and question the reliability of the methods used. Despite that there is no consensus on the origin of these ovarian stem cells, private companies are now proposing to use their stem cell potential to treat human infertility.
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Oogénesis , Ovario/citología , Células Madre/fisiología , Adulto , Animales , Diferenciación Celular , ARN Helicasas DEAD-box , Femenino , Humanos , Ratones , Modelos Biológicos , Oocitos/fisiologíaRESUMEN
CFTR protein regulates electrolyte and fluid transport in almost all tissues with exocrine function, including male reproductive tract. Mutation of CFTR gene causes cystic fibrosis (CF), which affects the function of several organs, and impairs male fertility. The role of CFTR protein in different compartments of male reproductive tract (testis, epididymis, sperm) as well as an impact of CFTR mutation(s) on male fertility phenotype is discussed in relation with the choice of optimal technique for Assisted Reproductive Techniques (ART) management.
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Regulador de Conductancia de Transmembrana de Fibrosis Quística/genética , Fertilidad/genética , Infertilidad Masculina/genética , Inyecciones de Esperma Intracitoplasmáticas/métodos , Animales , Regulador de Conductancia de Transmembrana de Fibrosis Quística/metabolismo , Asesoramiento Genético/métodos , Humanos , Infertilidad Masculina/patología , Infertilidad Masculina/terapia , Masculino , Mutación , Espermatozoides/metabolismo , Resultado del TratamientoRESUMEN
While arsenous acid, As(OH)3, has been the subject of a plethora of studies due to its worldwide ubiquity and its toxicity, pentavalent As in the form of arsenic acid, AsO(OH)3, has recently been found in rivers in central Mexico as the most abundant naturally occurring arsenic species. To better understand the solvation patterns of both toxic acids at the molecular level, we report the results of Born-Oppenheimer molecular dynamics simulations on the aqueous solvation of the AsO(OH)3 and As(OH)3 molecules at room temperature using the cluster microsolvation approach including 30 water molecules at the B3LYP/6-31G** level of theory. We found that the average per-molecule water binding energy is ca. 1 kcal mol-1 larger for the As(v) species as compared to the As(iii) one. To account for the asymmetry of both molecules, the hydration patterns were studied separately for a "lower" hemisphere, defined by the initially protonated oxygens, and for the opposite "upper" hemisphere. Similar lower hydration patterns were found for both As(iii) and As(v), with the same coordination number CN = 7. The upper pattern for As(iii) was found to be of a hydrophobic type, whereas that for As(v) showed the fourth oxygen to be hydrogen-bonded to the water network, yielding CN = 3.7; moreover, a proton "hopped" from the lower to the upper side, through the Grotthuss mechanism. Theoretical EXAFS spectra were obtained that showed good agreement with experimental data for As(iii) and As(v) in liquid water, albeit with somewhat longer As-O distances due to the level of theory employed. Proton transfer processes were also addressed; we found that the singly deprotonated H2AsO3- species largely dominated (99% of the simulation) for the As(iii) case, and that the deprotonated H2AsO4- and HAsO42- species were almost equally present (45% and 55%, respectively) for the As(v) case, which is in line with the experimental data pKa1 = 2.24 and pKa2 = 6.96. Through vibrational analysis the features of the Eigen and Zundel ions were found in the spectra of the microsolvated As(iii) and As(v) species, in good agreement with experimental data in aqueous solutions.
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PURPOSE: To report total fluid intake (TFI) and the intake of different fluid types in adults (≥ 18 years old) from Mexico, Argentina, Brazil and Uruguay. To compare intakes between countries and with recommended adequate intake (AI) of water from fluids. METHODS: Cross-sectional data were collected using a validated liquid intake 7-day record (Liq.In 7 ) in populations from Argentina (n = 1089), Brazil (n = 477), Mexico (n = 1677) and Uruguay (n = 554). Population characteristics, including age, gender, body mass index and socioeconomic level were recorded. Mean TFI was compared with the AI of water from fluids set by the USA Institute of Medicine. RESULTS: The lowest TFI was recorded in Mexican women (1748 mL/day) and the highest in Argentinean men (2318 mL/day). Median daily TFI was significantly different between countries; Uruguay and Argentina had higher values than Mexico and Brazil. In the former, plain water contributed to only 25% of TFI, the remainder being predominantly from hot beverages. Approximately, a third of adults did not drink enough fluid to meet the recommended AI. High SSB consumption was reported, which was significantly different between countries (p < 0.05), the highest being in Mexico (median 25-75th percentiles): 531 (300-895 mL/day. CONCLUSIONS: This survey highlights the need to increase water consumption and reduce SSB intake in this region to avoid potential associated health risks. These findings may be useful information in monitoring public health policy strategies.
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Bebidas/estadística & datos numéricos , Ingestión de Líquidos , Encuestas Nutricionales , Adolescente , Adulto , Argentina , Brasil , Comparación Transcultural , Estudios Transversales , Deshidratación , Femenino , Humanos , Masculino , México , Persona de Mediana Edad , Uruguay , Adulto JovenRESUMEN
PURPOSE: The primary aim of this survey was to report total fluid intake (TFI) and different fluid types for children (4-9 years) and adolescents (10-17 years) in Mexico, Brazil, Argentina and Uruguay. The second aim was to compare TFI with the adequate intake (AI) of water from fluids as recommended by the USA Institute of Medicine. METHODS: Data were collected using a validated liquid intake 7-day record (Liq.In 7 ). Participants' characteristics, including age, sex and anthropometric measurements were recorded. RESULTS: A total of 733 children and 933 adolescents were recruited. Over 75% of children in Uruguay met the IOM's recommended intake. Fewer children in Argentina (64-72%) and Brazil (41-50%) obtained AI and the lowest values were recorded in Mexico (33-44%), where 16% of boys and 14% girls drank 50% or less of the AI. More adolescents in Argentina (42%) met the AIs than other countries; the lowest was in Mexico (28%). Children and adolescents in Mexico and Argentina drank more sugar sweetened beverages than water. CONCLUSIONS: Large numbers of children and adolescents did not meet AI recommendations for TFI, raising concerns about their hydration status and potential effects on mental and physical well-being. Given the negative effects on children's health, the levels of SSB consumption are worrying.
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Bebidas/estadística & datos numéricos , Ingestión de Líquidos , Encuestas Nutricionales , Adolescente , Argentina , Brasil , Niño , Preescolar , Estudios Transversales , Femenino , Humanos , Masculino , México , UruguayRESUMEN
The hydration features of [Mg(H2O)n]2+ and [Ca(H2O)n]2+ clusters with n = 3-6, 8, 18, and 27 were studied by means of Born-Oppenheimer molecular dynamics simulations at the B3LYP/6-31+G** level of theory. For both ions, it is energetically more favorable to have all water molecules in the first hydration shell when n ≤ 6, but stable lower coordination average structures with one water molecule not directly interacting with the ion were found for Mg2+ at room temperature, showing signatures of proton transfer events for the smaller cation but not for the larger one. A more rigid octahedral-type structure for Mg2+ than for Ca2+ was observed in all simulations, with no exchange of water molecules to the second hydration shell. Significant thermal effects on the average structure of clusters were found: while static optimizations lead to compact, spherically symmetric hydration geometries, the effects introduced by finite-temperature dynamics yield more prolate configurations. The calculated vibrational spectra are in agreement with infrared spectroscopy results. Previous studies proposed an increase in the coordination number (CN) from six to eight water molecules for [Ca(H2O)n]2+ clusters when n ≥ 12; however, in agreement with recent measurements of binding energies, no transition to a larger CN was found when n > 8. Moreover, the excellent agreement found between the calculated extended X-ray absorption fine structure spectroscopy spectra for the larger cluster and the experimental data of the aqueous solution supports a CN of six for Ca2+.
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BACKGROUND: Liver transplantation has become commonplace for patients with end-stage liver disease. The liver is a bodily organ of great importance, and its dysfunction can cause significant complications throughout the body. Patients with hepatic disease should be able to acquire knowledge of the physiology of the liver via the dental profession, and it is also necessary to modify some aspects of dental treatment even in healthy patients. Problems such as excessive bleeding and hepatotoxicity caused by some of the drugs used in dental treatment can lead to a decrease in systemic health. Otherwise, patients with liver disease will have poorer oral health than the general population. Thus, it is important to have well-established routine dental care in this patient group and offer management of oral health in view of the effects of liver disease. METHODS: The objective of this work was to undertake a bibliographic review of the dental approaches to patients with liver disease and liver transplant recipients and to propose a dental care routine for such patients in an outpatient setting. RESULTS: A search was carried out on the main scientific databases (PubMed, Medline, and SciELO) for publications related to this subject and, particularly those published after 2010. The articles selected describe poor oral hygiene among patients, independent of the etiology of their liver disease. These patients also had a high index of xerostomia, caries, periodontal disease, apical lesions, and fungical infections. To control bleeding during and after surgery, hemostatic measures must be understood and adopted. CONCLUSION: There are no data about routine dental care among liver disease/transplantation patients. Thus, our findings will hopefully encourage other services to structure their approaches and consider enhancing their dental care protocols for patients with liver-related complications.
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Atención Dental para Enfermos Crónicos/organización & administración , Enfermedad Hepática en Estado Terminal/fisiopatología , Trasplante de Hígado/efectos adversos , Enfermedades Periodontales/terapia , Complicaciones Posoperatorias/terapia , Adulto , Caries Dental/etiología , Caries Dental/terapia , Enfermedad Hepática en Estado Terminal/cirugía , Femenino , Humanos , Masculino , Salud Bucal , Pacientes Ambulatorios , Enfermedades Periodontales/etiología , Complicaciones Posoperatorias/etiología , Periodo Posoperatorio , Xerostomía/etiología , Xerostomía/terapiaRESUMEN
One of the fundamental steps needed to design functional tissues and, ultimately organs is the ability to fabricate thick and densely populated tissue constructs with controlled vasculature and microenvironment. To date, bioprinting methods have been employed to manufacture tissue constructs with open vasculature in a square-lattice geometry, where the majority lacks the ability to be directly perfused. Moreover, it appears to be difficult to fabricate vascular tissue constructs targeting the stiffness of soft tissues such as the liver. Here we present a method for the fabrication of thick (e.g. 1â¯cm) and densely populated (e.g. 10â¯millionâ¯cells·mL-1) tissue constructs with a three-dimensional (3D) four arm branch network and stiffness in the range of soft tissues (1-10â¯kPa), which can be directly perfused on a fluidic platform for long time periods (>14â¯days). Specifically, we co-print a 3D four-arm branch using water-soluble Poly(vinyl alcohol) (PVA) as main material and Poly(lactic acid) (PLA) as the support structure. The PLA support structure was selectively removed, and the water soluble PVA structure was used for creating a 3D vascular network within a customized extracellular matrix (ECM) targeting the stiffness of the liver and with encapsulated hepatocellular carcinoma (HepG2) cells. These constructs were directly perfused with medium inducing the proliferation of HepG2 cells and the formation of spheroids. The highest spheroid density was obtained with perfusion, but overall the tissue construct displayed two distinct zones, one of rapid proliferation and one with almost no cell division and high cell death. The created model, therefore, simulate gradients in tissues of necrotic regions in tumors. This versatile method could represent a fundamental step in the fabrication of large functional and complex tissues and finally organs. STATEMENT OF SIGNIFICANCE: Vascularization within hydrogels with mechanical properties in the range of soft tissues remains a challenge. To date, bioprinting have been employed to manufacture tissue constructs with open vasculature in a square-lattice geometry that are most of the time not perfused. This study shows the creation of densely populated tissue constructs with a 3D four arm branch network and stiffness in the range of soft tissues, which can be directly perfused. The cells encapsulated within the construct showed proliferation as a function of the vasculature distance, and the control of the micro-environment induced the encapsulated cells to aggregate in spheroids in specific positions. This method could be used for modeling tumors and for fabricating more complex and densely populated tissue constructs with translational potential.
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Materiales Biocompatibles , Vasos Sanguíneos/crecimiento & desarrollo , Hígado/irrigación sanguínea , Impresión Tridimensional , Ingeniería de Tejidos , Bioimpresión , Matriz Extracelular , Células Hep G2 , Humanos , Hidrogeles , Perfusión , Poliésteres , Alcohol Polivinílico , Andamios del TejidoRESUMEN
In this work, a theoretical investigation was made to assess the coordination properties of Pb(ii) in [Pb(H2O)n]2+ clusters, with n = 4, 6, 8, 12, and 29, as well as to study proton transfer events, by means of Born-Oppenheimer molecular dynamics simulations at the B3LYP/aug-cc-pVDZ-pp/6-311G level of theory, that were calibrated in comparison with B3LYP/aug-cc-pVDZ-PP/aug-cc-pVDZ calculations. Hemidirected configurations were found in all cases; the radial distribution functions (RDFs) produced well defined first hydration shells (FHSs) for n = 4,6,8, and 12, that resulted in a coordination number CN = 4, whereas a clear-cut FHS was not found for n = 29 because the RDF did not have a vacant region after the first maximum; however, three water molecules remained directly interacting with the Pb ion for the whole simulation, while six others stayed at average distances shorter than 4 Å but dynamically getting closer and farther, thus producing a CN ranging from 6 to 9, depending on the criterion used to define the first hydration shell. In agreement with experimental data and previous calculations, proton transfer events were observed for n≤8 but not for n≥12. For an event to occur, a water molecule in the second hydration shell had to make a single hydrogen bond with a water molecule in the first hydration shell.
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Este estudo reuniu evidências acerca do altruísmo como um traço de personalidade. Participaram 438pessoas, divididas igualmente entre respondentes e seus informantes. Estes responderam os seguintesinstrumentos: Escala de Altruísmo Autoinformado, Questionário de Gratidão, Escala de Disposição paraPerdoar e Escala de Desejabilidade Social, além de perguntas demográficas; os informantes deramrespostas aos instrumentos descrevendo quais eram as características dos respondentes. Os resultadosindicaram convergência das estruturas fatoriais e consistência interna da medida de altruísmo,constatando-se correlação entre as medidas auto e heteroinformadas, assim como um padrão deassociação congruente de suas pontuações com disposição para perdoar. Concluiu-se que existemevidências do altruísmo como um traço de personalidade, que independe de contexto situacional, estandosua medida dissociada de desejabilidade social(AU)