The competing influence of surface roughness, hydrophobicity, and electrostatics on protein dynamics on a self-assembled monolayer.

Surface morphology, in addition to hydrophobic and electrostatic effects, can alter how proteins interact with solid surfaces. Understanding the heterogeneous dynamics of protein adsorption on surfaces with varying roughness is experimentally challenging. In this work, we use single-molecule fluorescence microscopy to study the adsorption of α-lactalbumin protein on the glass substrate covered with a self-assembled monolayer (SAM) with varying surface concentrations. Two distinct interaction mechanisms are observed: localized adsorption/desorption and continuous-time random walk (CTRW). We investigate the origin of these two populations by simultaneous single-molecule imaging of substrates with both bare glass and SAM-covered regions. SAM-covered areas of substrates are found to promote CTRW, whereas glass surfaces promote localized motion. Contact angle measurements and atomic force microscopy imaging show that increasing SAM concentration results in both increasing hydrophobicity and surface roughness. These properties lead to two opposing effects: increasing hydrophobicity promotes longer protein flights, but increasing surface roughness suppresses protein dynamics resulting in shorter residence times. Our studies suggest that controlling hydrophobicity and roughness, in addition to electrostatics, as independent parameters could provide a means to tune desirable or undesirable protein interactions with surfaces.

[One hundred years of health in a demographic, epidemiological and public policy context: the transition of childhood morbidity and its challenges]. / Cien años de salud en un contexto demográfico, epidemiológico y de políticas públicas: la transición de la morbilidad infantil y sus desafíos.

Chile is in an advanced stage of demographic and epidemiological transition. It is in this scenario that the political, economic and health crisis occurred, with the social outbreak in 2019 and then the COVID-19 pandemic. The mortality of children and adolescents dropped significantly, however, changes in lifestyles and demotivation, associated with long confinement and worsening health of parents and caregivers triggered an epidemic of mental health, developmental and nutritional problems. Pediatricians were forced to reinvent themselves, exposing themselves to stress and burnout. The aim of the manuscript is to describe the demographic, epidemiological and public policy context of child health in Chile in the last century, as a backdrop to dimension the immediate impact of the COVID-19 pandemic. The new health challenges for this age group in the medium and long term are discussed. Some theories, conceptualizations, and relevant milestones of the public health system in Chile are presented. The emergence of "post-pandemic morbidity", such as sedentary lifestyle, food insecurity, screen addiction, identity conflicts, violence, mental health disorders and reemergence of morbidity and mortality due to infectious and contagious diseases is discussed. Professionals responsible for the care of children must redouble their efforts to provide comprehensive care, accompanying families in the new challenges, in order to rehabilitate a healthy childhood.

Untying the Gordian KNOT: Unbiased Single Particle Tracking Using Point Clouds and Adaptive Motion Analysis.

Achieving mechanistic understanding of transport in complex environments such as inside cells or at polymer interfaces is challenging. We need better ways to image transport in 3-D and better single particle tracking algorithms to determine transport that are not systemically biased toward any classical motion model. Here we present an unbiased single particle tracking algorithm: Knowing Nothing Outside Tracking (KNOT). KNOT uses point clouds provided by iterative deconvolution to educate individual particle localizations and link particle positions between frames to achieve 2-D and 3-D tracking. Information from prior point clouds fuels an independent adaptive motion model for each particle to avoid global models that could introduce biases. KNOT competes with or surpasses other 2-D methods from the 2012 particle tracking challenge while accurately tracking adsorption dynamics of proteins on polymer surfaces and early endosome transport in live cells in 3-D. We apply KNOT to study 3-D endosome transport to reveal new physical insight into locally directed and diffusive transport in live cells. Our analysis demonstrates better accuracy in classifying local motion and its direction compared to previous methods, revealing intricate intracellular transport heterogeneities.

Single-Molecule Dynamics Reflect IgG Conformational Changes Associated with Ion-Exchange Chromatography.

Conformational changes of antibodies and other biologics can decrease the effectiveness of pharmaceutical separations. Hence, a detailed mechanistic picture of antibody-stationary phase interactions that occur during ion-exchange chromatography (IEX) can provide critical insights. This work examines antibody conformational changes and how they perturb antibody motion and affect ensemble elution profiles. We combine IEX, three-dimensional single-protein tracking, and circular dichroism spectroscopy to investigate conformational changes of a model antibody, immunoglobulin G (IgG), as it interacts with the stationary phase as a function of salt conditions. The results indicate that the absence of salt enhances electrostatic attraction between IgG and the stationary phase, promotes surface-induced unfolding, slows IgG motion, and decreases elution from the column. Our results reveal previously unreported details of antibody structural changes and their influence on macroscale elution profiles.

Imaging Switchable Protein Interactions with an Active Porous Polymer Support.

Mechanistic details about how local physicochemistry of porous interfaces drives protein transport mechanisms are necessary to optimize biomaterial applications. Cross-linked hydrogels made of stimuli-responsive polymers have potential for active protein capture and release through tunable steric and chemical transformations. Simultaneous monitoring of dynamic changes in both protein transport and interfacial polymer structure is an experimental challenge. We use single-particle tracking (SPT) and fluorescence correlation spectroscopy Super-resolution Optical Fluctuation Imaging (fcsSOFI) to relate the switchable changes in size and structure of a pH-responsive hydrogel to the interfacial transport properties of a model protein, lysozyme. SPT analysis reveals the reversible switching of protein transport dynamics in and at the hydrogel polymer in response to pH changes. fcsSOFI allows us to relate tunable heterogeneity of the hydrogels and pores to reversible changes in the distribution of confined diffusion and adsorption/desorption. We find that physicochemical heterogeneity of the hydrogels dictates protein confinement and desorption dynamics, particularly at pH conditions in which the hydrogels are swollen.

Madres y padres de adolescentes urbanos: percepciones y expectativas de la atención en salud sexual y reproductiva para sus hijos / Parental perceptions and expectations about sexual and reproductive health care for urban adolescents

Studies have reported which expectations and demands adolescents have for more accessible sexual and reproductive health (SRH) services. However, there is limited information regarding parents’ requirements and demands for SRH services their adolescents need. Aim: To explore the knowledge of parents regarding SRH needs of their adolescent daughters and sons and what they demand from primary health care services (PHCS). Material and Methods: A quali-quantitative, descriptive, cross-sectional study was performed. Nine fathers and 24 mothers were interviewed to design a survey. In the quantitative phase, 125 mothers voluntarily, anonymously and confidentially were interviewed. All participants were users of PHCS of urban communities in the Metropolitan Area showing a high percentage of births by adolescents’ mothers. Data analysis was descriptive and analytical. Results: Interviews served as input to design the questionnaire. Seventy seven percent (77,6%) of interviewed mothers knew that their sons/daughters, regardless of their gender, had concern about sexuality; their main fear was adolescent pregnancy. Seventy six percent (76%) was aware that their sons/daughters might request attention in SRH clinics and 97% agreed that they should require these services during early adolescence. The most desirable features of such services were identified. Conclusions: Parents recognize that they would prefer their sons/daughters postponed sexual initiation; however, they are aware that pregnancy prevention is needed. Mothers approve SRH services. They agree that counseling to prevent pregnancies and sexual transmitted diseases (STD) and AIDS was an important issue. They require support for themselves and their sons/daughters.

[Parental perceptions and expectations about sexual and reproductive health care for urban adolescents]. / Madres y padres de adolescentes urbanos: percepciones y expectativas de la atención en salud sexual y reproductiva para sus hijos.

UNLABELLED: Studies have reported which expectations and demands adolescents have for more accessible sexual and reproductive health (SRH) services. However, there is limited information regarding parents' requirements and demands for SRH services their adolescents need. AIM: To explore the knowledge of parents regarding SRH needs of their adolescent daughters and sons and what they demand from primary health care services (PHCS). MATERIAL AND METHODS: A quali-quantitative, descriptive, cross-sectional study was performed. Nine fathers and 24 mothers were interviewed to design a survey. In the quantitative phase, 125 mothers voluntarily, anonymously and confidentially were interviewed. All participants were users of PHCS of urban communities in the Metropolitan Area showing a high percentage of births by adolescents' mothers. Data analysis was descriptive and analytical. RESULTS: Interviews served as input to design the questionnaire. Seventy seven percent (77,6%) of interviewed mothers knew that their sons/daughters, regardless of their gender, had concern about sexuality; their main fear was adolescent pregnancy. Seventy six percent (76%) was aware that their sons/daughters might request attention in SRH clinics and 97% agreed that they should require these services during early adolescence. The most desirable features of such services were identified. CONCLUSIONS: Parents recognize that they would prefer their sons/daughters postponed sexual initiation; however, they are aware that pregnancy prevention is needed. Mothers approve SRH services. They agree that counseling to prevent pregnancies and sexual transmitted diseases (STD) and AIDS was an important issue. They require support for themselves and their sons/daughters.

Gentamicina en dosis fraccionada y única diaria: comparación de eficacia, toxicidad y costo / Gentamicine in fractioned and single dose a day: comparisson of efficacy, toxicity and cost

En un estudio prospectivo se comparó eficacia, toxicidad renal, coclear y vestibular de gentamicina administrada en dosis fraccionada de 1,7 mg/kg peso cada 8 horas (DF) y dosis única de 3 mg/kg peso/día (DU). El sitio de la infección fue apendicular en 13 casos, urinario en 11, perianal en 9 y otros en 6 casos. En el 59 por ciento de los pacientes se aisló Escherichia coli y en el 23 por ciento otros gérmenes Gram negativos. Fueron tratados 21 pacientes con DF y 18 con DU. La evolución fue similar en relación al número de días con fiebre y compromiso del estado general de los pacientes. El recuento de glóbulos blancos, VHS y proteína C reactiva aumentaron al inicio del tratamiento, pero se normalizaron en ambos grupos al término del mismo. Se registraron 3 fracasos de tratamiento con DF y 1 con DU. La creatinina plasmática no se modificó al término del tratamiento (p = 0,79) y en un control a los 30 días post tratamiento (p = 0,79). El clearence de creatinina se redujo en ambos grupos, siendo esta reducción al término del tratamiento más severa en el grupo DU, pero sin alcanzar significación estadística (p = 0,62), con normalización a los 30 días. La evaluación del 8º par a través de pérdida de audición de frecuencia específica,pérdida media para frecuencias altas y pruebas calóricas no identificó daño post tratamiento en ambos grupos hasta 30 días de seguimiento. El costo diario de la DF fue de $ 1.552 y de la DU de $ 141. El consumo de tiempo de la administración de la DF fue nueve veces mayor. En conclusión, la modalidad de tratamiento con gentamicina en dosis única diaria resultó efectiva,segura, con menos fracasos de tratamiento, considerablemente más barata y de más rápida administración que la alternativa de dosis fraccionada, por lo que recomendamos el uso de gentamicina en dosis única diaria de 3 mg/kg/día