Dynamics of Single-Chain Nanoparticles under Crowding: A Neutron Spin Echo Study.

We present a neutron spin echo (NSE) investigation to examine the impact of macromolecular crowding on the dynamics of single-chain nanoparticles (SCNPs), serving as synthetic models for biomacromolecules with flexibility and internal degrees of freedom, such as intrinsically disordered proteins (IDPs). In particular, we studied the dynamics of a medium-size poly(methyl methacrylate) (PMMA)-based SCNP (33 kDa) in solutions with low- (10 kDa) and high- (100 kDa) molecular weight analogous deuterated PMMA linear crowders. The dynamic structure factors of the SCNPs in dilute solution show certain degrees of freedom, yet the analysis in terms of the Zimm model reveals high internal friction that effectively stiffens the chain-a phenomenon also observed for IDPs. Under crowding conditions, the internal dynamics remains essentially unchanged, but the center-of-mass diffusion slows down. The effective viscosity felt by the SCNPs at the timescales probed by NSE is lower than the macroscopic viscosity of the crowder solution, and it does not depend significantly on the molecular weight.

Cryopreservation of cerebrospinal fluid cells preserves the transcriptional landscape for single-cell analysis.

Cerebrospinal fluid (CSF) matrix biomarkers have become increasingly valuable surrogate markers of neuropsychiatric diseases in research and clinical practice. In contrast, CSF cells have been rarely investigated due to their relative scarcity and fragility, and lack of common collection and cryopreservation protocols, with limited exceptions for neurooncology and primary immune-based diseases like multiple sclerosis. the advent of a microfluidics-based multi-omics approach to studying individual cells has allowed for the study of cellular phenotyping, intracellular dynamics, and intercellular relationships that provide multidimensionality unable to be obtained through acellular fluid-phase analyses. challenges to cell-based research include site-to-site differences in handling, storage, and thawing methods, which can lead to inaccuracy and inter-assay variability. In the present study, we performed single-cell RNA sequencing (10x Genomics) on fresh or previously cryopreserved human CSF samples from three alternative cryopreservation methods: Fetal Bovine Serum with Dimethyl sulfoxide (FBS/DMSO), FBS/DMSO after a DNase step (a step often included in epigenetic studies), and cryopreservation using commercially available Recovery© media. In comparing relative differences between fresh and cryopreserved samples, we found little effect of the cryopreservation method on being able to resolve donor-linked cell type proportions, markers of cellular stress, and overall gene expression at the single-cell level, whereas donor-specific differences were readily discernable. We further demonstrate the compatibility of fresh and cryopreserved CSF immune cell sequencing using biologically relevant sexually dimorphic gene expression differences by donor. Our findings support the utility and interchangeability of FBS/DMSO and Recovery cryopreservation with fresh sample analysis, providing a methodological grounding that will enable researchers to further expand our understanding of the CSF immune cell contributions to neurological and psychiatric disease.

Enhancing disinfection and microcontaminant removal by coupling LED driven UVC and UVA/photo-Fenton processes in continuous flow reactors.

For the first time, the sequential combination of UVC-LED (276 nm) and photo-Fenton/UVA-LED (376 nm) process has been assessed in continuous flow mode for wastewater reclamation according to the new European Regulation for reuse in agricultural irrigation (EU 2020/741). The results show that it is possible to obtain water quality class B (Escherichia coli ≤ 100 CFU/100 mL) by UVC-LED irradiation alone, operating the system with a hydraulic residence time (HRT) of 6.5 min and liquid depth of 5 cm in the case of secondary effluents with low Escherichia coli load (8.102-3.1.103 CFU/100 mL). As for high bacteria concentrations (1.2-4.2.104 CFU/100 mL), HRTs longer than 30 min are required. The bacterial load has not influenced decontamination, removing 18 ± 4 % of microcontaminants. Coupling the UVC (30-min HRT and 5.0 cm liquid depth) and the UVA/photo-Fenton (60-min and 15-cm liquid depth) systems allows 58 ± 4 % of real organic microcontaminants to be removed, in addition to achieving water quality class B.

Structure of Single-Chain Nanoparticles under Crowding Conditions: A Random Phase Approximation Approach.

The conformation of poly(methyl methacrylate) (PMMA)-based single-chain nanoparticles (SCNPs) and their corresponding linear precursors in the presence of deuterated linear PMMA in deuterated dimethylformamide (DMF) solutions has been studied by small-angle neutron scattering (SANS). The SANS profiles were analyzed in terms of a three-component random phase approximation (RPA) model. The RPA approach described well the scattering profiles in dilute and crowded solutions. Considering all the contributions of the RPA leads to an accurate estimation of the single chain form factor parameters and the Flory-Huggins interaction parameter between PMMA and DMF. The value of the latter in the dilute regime indicates that the precursors and the SCNPs are in good solvent conditions, while in crowding conditions, the polymer becomes less soluble.

Life Satisfaction and Character Strengths in Women With Breast Cancer: Zest and Hope as Predictors.

BACKGROUND: Empirical evidence shows that life satisfaction is positively related to character strengths, and although this association has been observed in different populations, it is scarce in breast cancer patients. This study analyzes the relationship between character strengths and life satisfaction in Spanish women diagnosed with breast cancer. METHODS: A sample of 117 women completed the Satisfaction with Life Scale (SWLS) and the Spanish version of the VIA Inventory of Strengths (VIA-IS). Correlation analysis and regression modeling were performed to determine which strengths predict life satisfaction. RESULTS: The results of the correlation analysis showed that 15 strengths were positively and significantly associated with life satisfaction, with the highest correlations corresponding to zest, hope, curiosity, social intelligence, love, gratitude, and judgment. Regression modeling indicated that of these, zest and hope were key strengths for predicting life satisfaction. CONCLUSIONS: These findings suggest that intervention programs based on the development of zest and hope could help to improve life satisfaction and, therefore, the psychological well-being of women with breast cancer.

CD300f immune receptor contributes to healthy aging by regulating inflammaging, metabolism, and cognitive decline.

Emerging evidence suggests that immune receptors may participate in many aging-related processes such as energy metabolism, inflammation, and cognitive decline. CD300f, a TREM2-like lipid-sensing immune receptor, is an exceptional receptor as it integrates activating and inhibitory cell-signaling pathways that modulate inflammation, efferocytosis, and microglial metabolic fitness. We hypothesize that CD300f can regulate systemic aging-related processes and ultimately healthy lifespan. We closely followed several cohorts of two strains of CD300f-/- and WT mice of both sexes for 30 months and observed an important reduction in lifespan and healthspan in knockout mice. This was associated with systemic inflammaging, increased cognitive decline, reduced brain glucose uptake observed by 18FDG PET scans, enrichment in microglial aging/neurodegeneration phenotypes, proteostasis alterations, senescence, increased frailty, and sex-dependent systemic metabolic changes. Moreover, the absence of CD300f altered macrophage immunometabolic phenotype. Taken together, we provide strong evidence suggesting that myeloid cell CD300f immune receptor contributes to healthy aging.

Neat Protein Single-Chain Nanoparticles from Partially Denatured BSA.

The main challenge for the preparation of protein single-chain nanoparticles (SCNPs) is the natural complexity of these macromolecules. Herein, we report the suitable conditions to produce "neat" bovine serum albumin (BSA) single-chain nanoparticles (SCNPs) from partially denatured BSA, which involves denaturation in urea and intramolecular cross-linking below the overlap concentration. We use two disuccinimide ester linkers containing three and six methylene spacer groups: disuccinimidyl glutarate (DSG) and disuccinimidyl suberate (DSS), respectively. Remarkably, the degree of internal cross-linking can be followed simply and efficiently via 1H NMR spectroscopy. The associated structural changes-as probed by small-angle neutron scattering (SANS)-reveal that the denatured protein has a random-like coil conformation, which progressively shrinks with the addition of DSG or DSS, thus allowing for size control of the BSA-SCNPs with radii of gyration down to 5.4 nm. The longer cross-linker exhibits slightly more efficiency in chain compaction with a somewhat stronger size reduction but similar reactivity at a given cross-linker concentration. This reliable method is applicable to a wide range of compact proteins since most proteins have appropriate reactive amino acids and denature in urea. Critically, this work paves the way to the synthesis of "neat", biodegradable protein SCNPs for a range of applications including nanomedicine.

Effects of LED Light Spectra on the Development, Phytochemical Profile, and Antioxidant Activity of Curcuma longa from Easter Island.

Curcuma longa (C. longa), an herbaceous plant used for medicinal purposes by the indigenous people of Easter Island, has been overexploited in its natural habitat, leading to its conservation status being designated as a vulnerable species. We have recently reported on the use of light-emitting diodes (LEDs) to improve the productivity of C. longa in vitro cultures under a temporary immersion system (TIS), but the effects of light quality on plant growth, phytochemical composition, and antioxidant capacity remained unexplored. Here, we set out to study these three aspects as observed at the end of TIS culture (day 0) and after 30 days of greenhouse acclimation (day 30). Thus, we evaluated plant morphological characteristics, phytochemical profile (polyphenols, tannins, flavonoids, reducing sugars, and curcumin), and radical scavenging activity by DPPH, ORAC, and FRAP assays. The results showed that, during in vitro cultivation under TIS, the red:blue (RB) LED light spectrum promoted C. longa shoot proliferation, with the resulting seedlings exhibiting greater fresh weight and no signs of etiolation. In the acclimation phase, the RB spectrum increased phytochemicals, such as polyphenols, flavonoids, and reducing sugars, and boosted curcumin synthesis. Nevertheless, the antioxidant activity of the plants under the RB light spectrum did not intensify. We surmise that this may be due to the premature intraplant allocation of metabolites to alternative pathways (e.g., curcumin synthesis) under RB light.

Comparison of pneumonia features in children caused by SARS-CoV-2 and other viral respiratory pathogens.

BACKGROUND: Pneumonia is a frequent manifestation of coronavirus disease 2019 (COVID-19) in hospitalized children. METHODS: The study involved 80 hospitals in the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Spanish Pediatric National Cohort. Participants were children <18 years, hospitalized with SARS-CoV-2 community-acquired pneumonia (CAP). We compared the clinical and radiological characteristics of SARS-CoV-2-associated CAP with CAP due to other viral etiologies from ValsDance (retrospective) cohort. RESULTS: In total, 151 children with SARS-CoV-2-associated CAP and 138 with other viral CAP were included. Main clinical features of SARS-CoV-2-associated CAP were cough, fever, or dyspnea. Lymphopenia was found in 43% patients and 15% required admission to the pediatric intensive care unit (PICU). Chest X-ray revealed condensation (42%) and other infiltrates (58%). Compared with CAP from other viral pathogens, COVID-19 patients were older, with lower C-reactive protein (CRP) levels, less wheezing, and greater need of mechanical ventilation (MV). There were no differences in the use of continuous positive airway pressure (CPAP) or HVF, or PICU admission between groups. CONCLUSION: SARS-CoV-2-associated CAP in children presents differently to other virus-associated CAP: children are older and rarely have wheezing or high CRP levels; they need less oxygen but more CPAP or MV. However, several features overlap and differentiating the etiology may be difficult. The overall prognosis is good.

Efectos del Ejercicio Físico Aeróbico sobre los Factores de Riesgo Modificables que Predisponen a un Segundo Evento de Accidente Cerebrovascular. Revisión Sistemática / Effects of Aerobic Physical Exercise on Modifiable Risk Factors that Predispose to a Second Stroke Event. Systematic review

Introducción. El accidente cerebrovascular (ACV) es una condición de salud que ha aumentado su prevalencia en los últimos años, la cual se encuentra intrínsecamente asociada a la presencia de enfermedades crónicas no transmisibles (ECNT), como lo son la diabetes mellitus, dislipidemia e hipertensión, las que, de no ser controladas tras la instauración del primer episodio, predisponen a la afección de un segundo evento de ACV. Es sabido que el ejercicio físico aeróbico juega un rol fundamental en el control de las ECNT, junto con otros factores, como lo son los cambios de hábitos y adherencia a los tratamientos farmacológicos. Objetivo. Analizar los efectos que tiene el ejercicio físico aeróbico en población secuelada de un ACV sobre las ECNT que predisponen a sufrir un segundo evento cerebrovascular. Método. Se realizó una exhaustiva búsqueda en las bases de datos EBSCO, Scielo, PubMed y PEdro, utilizando las palabras claves "stroke and modifiable risk factors and aerobic physical exercise"; obteniendo un total de 56438 artículos. Para la selección, se consideraron los siguientes criterios de inclusión: pacientes entre 45 y 65 años con secuelas de ACV de más de 6 meses, que analizaran el efecto del ejercicio físico sobre las ECNT tras un evento cerebrovascular. Resultados. Se seleccionaron tres artículos científicos tipo ensayo clínico aleatorizados controlados, los cuales analizan los efectos que produce el ejercicio físico aeróbico sobre las ECNT tras un ACV. Entre los resultados con mayor significancia estadística (P entre 0.01 y 0.05) se encuentra el aumento en el consumo peak de oxígeno y el aumento en el colesterol HDL. Conclusiones. Es indispensable sistematizar la información de los programas de rehabilitación neurológica, que permitan levantar datos de las intervenciones, y así poder potenciar el ejercicio físico aeróbico de forma segura para poder controlar las ECNT subyacentes y así prevenir futuros eventos cerebrovasculares.

Background. Cerebrovascular accident (CVA) is a health condition that has suspected its prevalence in recent years, which is intrinsically associated with the presence of chronic non-communicable diseases (CNCD), such as diabetes mellitus, dyslipidemia and hypertension, which, if not controlled after the establishment of the first episode, predispose to the condition of a second stroke event. It is known that aerobic physical exercise plays a fundamental role in the control of NCDs, along with other factors, such as changes in habits and adherence to pharmacological treatments. Objective. To analyze the effects of aerobic physical exercise in the population after a stroke on NCDs that predispose to a second cerebrovascular event. Method. An exhaustive search was carried out in the EBSCO, Scielo, PubMed and PEdro databases, using the keywords "stroke and modifiable risk factors and aerobic physical exercise"; obtaining a total of 56438 articles. For selection, consider the following inclusion criteria: patients between 45 and 65 years of age, stroke sequelae of more than 6 months, who will analyze the effect of physical exercise on NCDs after a cerebrovascular event. Results. Three controlled randomized clinical trial were selected, which analyze the effects produced by aerobic physical exercise on NCDs after a stroke. Among the results with the highest statistical significance (P between 0.01 and 0.05) is the increase in peak oxygen consumption and the increase in HDL cholesterol. Conclusion. It is essential to systematize the information on neurological rehabilitation programs, to collect data from the interventions, and thus be able to promote aerobic physical exercise safely to control the underlying NCDs and thus prevent future cerebrovascular events.

TRPV2: A Key Player in Myelination Disorders of the Central Nervous System.

Transient potential receptor vanilloid 2 (TRPV2) is widely expressed through the nervous system and specifically found in neuronal subpopulations and some glial cells. TRPV2 is known to be sensitized by methionine oxidation, which results from inflammation. Here we aim to characterize the expression and regulation of TRPV2 in myelination pathologies, such as hypomyelination and demyelination. We validated the interaction between TRPV2 and its putative interactor Opalin, an oligodendrocyte marker, in mixed glial cultures under pro- and anti-inflammatory conditions. Then, we characterized TRPV2 time-course expression in experimental animal models of hypomyelination (jimpy mice) and de-/remyelination (cuprizone intoxication and experimental autoimmune encephalomyelitis (EAE)). TRPV2 showed upregulation associated with remyelination, inflammation in cuprizone and EAE models, and downregulation in hypomyelinated jimpy mice. TRPV2 expression was altered in human samples of multiple sclerosis (MS) patients. Additionally, we analyzed the expression of methionine sulfoxide reductase A (MSRA), an enzyme that reduces oxidated methionines in TRPV2, which we found increased in inflammatory conditions. These results suggest that TRPV2 may be a key player in myelination in accordance with the recapitulation hypothesis, and that it may become an interesting clinical target in the treatment of demyelination disorders.

IGF-1 regulates astrocytic phagocytosis and inflammation through the p110α isoform of PI3K in a sex-specific manner.

Insulin-like growth factor-I (IGF-I) signaling plays a key role in neuroinflammation. Here we show that IGF-1 also regulates phagocytosis of reactive astrocytes through p110α isoform of phosphatidylinositol 3-kinase (PI3K), differentially in both sexes. Systemic bacterial lipopolysaccharide (LPS)-treatment increased the expression of GFAP, a reactive astrocyte marker, in the cortex of mice in both sexes and was blocked by IGF-1 only in males. In primary astrocytes, LPS enhanced the mRNA expression of Toll-like receptors (TLR2,4) and proinflammatory factors: inducible nitric oxide synthase (iNOS), chemokine interferon-γ-inducible protein-10 (IP-10) and cytokines (IL-1ß, IL-6, and IL-10) in male and female. Treatment with IGF-1 counteracted TLR4 but not TLR2, iNOS, and IP10 expression in both sexes and cytokines expression in males. Furthermore, reactive astrocyte phagocytosis was modulated by IGF-1 only in male astrocytes. IGF-1 was also able to increase AKT-phosphorylation only in male astrocytes. PI3K inhibitors, AG66, TGX-221, and CAL-101, with selectivity toward catalytic p110α, p110ß, and p110δ isoforms respectively, reduced AKT-phosphorylation in males. All isoforms interact physically with IGF-1-receptor in both sexes. However, the expression of p110α is higher in males while the expression of IGF-1-receptor is similar in male and female. AG66 suppressed the IGF-1 effect on cytokine expression and counteracted the IGF-1-produced phagocytosis decrease in male reactive astrocytes. Results suggest that sex-differences in the effect of IGF-1 on the AKT-phosphorylation could be due to a lower expression of the p110α in female and that IGF-1-effects on the inflammatory response and phagocytosis of male reactive astrocytes are mediated by p110α/PI3K subunit.

Chronic IL-10 overproduction disrupts microglia-neuron dialogue similar to aging, resulting in impaired hippocampal neurogenesis and spatial memory.

The subgranular zone of the dentate gyrus is an adult neurogenic niche where new neurons are continuously generated. A dramatic hippocampal neurogenesis decline occurs with increasing age, contributing to cognitive deficits. The process of neurogenesis is intimately regulated by the microenvironment, with inflammation being considered a strong negative factor for this process. Thus, we hypothesize that the reduction of new neurons in the aged brain could be attributed to the age-related microenvironmental changes towards a pro-inflammatory status. In this work, we evaluated whether an anti-inflammatory microenvironment could counteract the negative effect of age on promoting new hippocampal neurons. Surprisingly, our results show that transgenic animals chronically overexpressing IL-10 by astrocytes present a decreased hippocampal neurogenesis in adulthood. This results from an impairment in the survival of neural newborn cells without differences in cell proliferation. In parallel, hippocampal-dependent spatial learning and memory processes were affected by IL-10 overproduction as assessed by the Morris water maze test. Microglial cells, which are key players in the neurogenesis process, presented a different phenotype in transgenic animals characterized by high activation together with alterations in receptors involved in neuronal communication, such as CD200R and CX3CR1. Interestingly, the changes described in adult transgenic animals were similar to those observed by the effect of normal aging. Thus, our data suggest that chronic IL-10 overproduction mimics the physiological age-related disruption of the microglia-neuron dialogue, resulting in hippocampal neurogenesis decrease and spatial memory impairment.

Loss of presenilin function enhances tau phosphorylation and aggregation in mice.

Mutations in the presenilin (PS/PSEN) genes encoding the catalytic components of γ-secretase accelerate amyloid-ß (Aß) and tau pathologies in familial Alzheimer's disease (AD). Although the mechanisms by which these mutations affect Aß are well defined, the precise role PS/γ-secretase on tau pathology in neurodegeneration independently of Aß is largely unclear. Here we report that neuronal PS deficiency in conditional knockout (cKO) mice results in age-dependent brain atrophy, inflammatory responses and accumulation of pathological tau in neurons and glial cells. Interestingly, genetic inactivation of presenilin 1 (PS1) or both PS genes in mutant human Tau transgenic mice exacerbates memory deficits by accelerating phosphorylation and aggregation of tau in excitatory neurons of vulnerable AD brain regions (e.g., hippocampus, cortex and amygdala). Remarkably, neurofilament (NF) light chain (NF-L) and phosphorylated NF are abnormally accumulated in the brain of Tau mice lacking PS. Synchrotron infrared microspectroscopy revealed aggregated and oligomeric ß-sheet structures in amyloid plaque-free PS-deficient Tau mice. Hippocampal-dependent memory deficits are associated with synaptic tau accumulation and reduction of pre- and post-synaptic proteins in Tau mice. Thus, partial loss of PS/γ-secretase in neurons results in temporal- and spatial-dependent tau aggregation associated with memory deficits and neurodegeneration. Our findings show that tau phosphorylation and aggregation are key pathological processes that may underlie neurodegeneration caused by familial AD-linked PSEN mutations.

Crowding Effects on the Structure and Dynamics of the Intrinsically Disordered Nuclear Chromatin Protein NUPR1.

The intracellular environment is crowded with macromolecules, including sugars, proteins and nucleic acids. In the cytoplasm, crowding effects are capable of excluding up to 40% of the volume available to any macromolecule when compared to dilute conditions. NUPR1 is an intrinsically disordered protein (IDP) involved in cell-cycle regulation, stress-cell response, apoptosis processes, DNA binding and repair, chromatin remodeling and transcription. Simulations of molecular crowding predict that IDPs can adopt compact states, as well as more extended conformations under crowding conditions. In this work, we analyzed the conformation and dynamics of NUPR1 in the presence of two synthetic polymers, Ficoll-70 and Dextran-40, which mimic crowding effects in the cells, at two different concentrations (50 and 150 mg/ml). The study was carried out by using a multi-spectroscopic approach, including: site-directed spin labelling electron paramagnetic resonance spectroscopy (SDSL-EPR), nuclear magnetic resonance spectroscopy (NMR), circular dichroism (CD), small angle X-ray scattering (SAXS) and dynamic light scattering (DLS). SDSL-EPR spectra of two spin-labelled mutants indicate that there was binding with the crowders and that the local dynamics of the C and N termini of NUPR1 were partially affected by the crowders. However, the overall disordered nature of NUPR1 did not change substantially in the presence of the crowders, as shown by circular dichroism CD and NMR, and further confirmed by EPR. The changes in the dynamics of the paramagnetic probes appear to be related to preferred local conformations and thus crowding agents partially affect some specific regions, further pinpointing that NUPR1 flexibility has a key physiological role in its activity.

Dynamic Processes and Mechanisms Involved in Relaxations of Single-Chain Nano-Particle Melts.

We present a combined study by quasielastic neutron scattering (QENS), dielectric and mechanical spectroscopy, calorimetry and wide-angle X-ray diffraction on single-chain nano-particles (SCNPs), using the corresponding linear precursor chains as reference, to elucidate the impact of internal bonds involving bulky cross-links on the properties of polymer melts. Internal cross-links do not appreciably alter local properties and fast dynamics. This is the case of the average inter-molecular distances, the ß-relaxation and the extent of the atomic displacements at timescales faster than some picoseconds. Contrarily, the α-relaxation is slowed down with respect to the linear precursor, as detected by DSC, dielectric spectroscopy and QENS. QENS has also resolved broader response functions and stronger deviations from Gaussian behavior in the SCNPs melt, hinting at additional heterogeneities. The rheological properties are also clearly affected by internal cross-links. We discuss these results together with those previously reported on the deuterated counterpart samples and on SCNPs obtained through a different synthesis route to discern the effect of the nature of the cross-links on the modification of the diverse properties of the melts.

Specific microglial phagocytic phenotype and decrease of lipid oxidation in white matter areas during aging: Implications of different microenvironments.

Physiological aging is characterized by an imbalance of pro-inflammatory and anti-inflammatory mediators leading to neuroinflammation. Microglial cells, which are highly regulated by the local microenvironment, undergo specific changes depending upon the brain area during aging. The aim of this study was to evaluate the influence of age over microglial cells along different brain areas and microenvironments. For this purpose, transgenic mice with overproduction of either the anti-inflammatory IL-10 cytokine or the pro-inflammatory IL-6 cytokine were used. Our results show that, during aging, microglial cells located in white matter (WM) areas maintain their phagocytic capacity but present a specific phagocytic phenotype with receptors involved in myelin recognition, arguing for aging-derived myelin damage. Whereas IL-10 overproduction anticipates the age-related microglial phagocytic phenotype, maintaining it over time, IL-6 overproduction exacerbates this phenotype in aging. These modifications were linked with a higher efficiency of myelin engulfment by microglia in aged transgenic animals. Moreover, we show, in a novel way, lower lipid oxidation during aging in WM areas, regardless of the genotype. The novelty of the insights presented in this study open a window to deeply investigate myelin lipid oxidation and the role of microglial cells in its regulation during physiological aging.

Using Microemulsions: Formulation Based on Knowledge of Their Mesostructure.

Microemulsions, as thermodynamically stable mixtures of oil, water, and surfactant, are known and have been studied for more than 70 years. However, even today there are still quite a number of unclear aspects, and more recent research work has modified and extended our picture. This review gives a short overview of how the understanding of microemulsions has developed, the current view on their properties and structural features, and in particular, how they are related to applications. We also discuss more recent developments regarding nonclassical microemulsions such as surfactant-free (ultraflexible) microemulsions or ones containing uncommon solvents or amphiphiles (like antagonistic salts). These new findings challenge to some extent our previous understanding of microemulsions, which therefore has to be extended to look at the different types of microemulsions in a unified way. In particular, the flexibility of the amphiphilic film is the key property to classify different microemulsion types and their properties in this review. Such a classification of microemulsions requires a thorough determination of their structural properties, and therefore, the experimental methods to determine microemulsion structure and dynamics are reviewed briefly, with a particular emphasis on recent developments in the field of direct imaging by means of electron microscopy. Based on this classification of microemulsions, we then discuss their applications, where the application demands have to be met by the properties of the microemulsion, which in turn are controlled by the flexibility of their amphiphilic interface. Another frequently important aspect for applications is the control of the rheological properties. Normally, microemulsions are low viscous and therefore enhancing viscosity has to be achieved by either having high concentrations (often not wished for) or additives, which do not significantly interfere with the microemulsion. Accordingly, this review gives a comprehensive account of the properties of microemulsions, including most recent developments and bringing them together from a united viewpoint, with an emphasis on how this affects the way of formulating microemulsions for a given application with desired properties.

[Evaluation of spoligotyping-smear sputum as an alternative and culture-independent methodology for Mycobacterium tuberculosis genotyping]. / Evaluación de spoligotyping a partir de baciloscopías como metodología alterna e independiente de cultivo para la genotipificación de Mycobacterium tuberculosis.

BACKGROUND: Tuberculosis (TB) remains as the second cause of death by an infectious disease preceded by the acquired immune deficiency syndrome (AIDS). Currently, laboratory techniques and methodologies of diagnosis and drug susceptibility testing are constantly changing. Therefore, it has been recommended the introduction of rapid assays based on the amplification of nucleic acids test (NAAT's) through a polymerase chain reaction (PCR). Based on this principle, outstands spoligotyping - as a genotype and molecular epidemiology tool in tuberculosis - it is standardized to use isolated bacteria for the study of Mycobacterium genome through the amplification of 43 non-repetitive sequences, located at the direct repetitive region 1 (RD1). AIM: Evaluation of spoligotyping from acid fast staining smears as an independent option from bacterial isolation to characterize Mycobacterium tuberculosis by using sputum samples from TB patients from National Cardiopulmonary Institute in Tegucigalpa, Honduras. METHOD: Of 37 patients with positive culture (and smear microscopy) for M. tuberculosis, 50 expectoration samples were obtained. Microbiological and molecular tests were performed in respiratory samples containing mycobacterial DNA from sputum smears, concentrates and solid culture, for identification and genotype analysis by spoligotyping technique. RESULTS: Spoligotyping was positive in 37/37 of positive culture samples (S: 100%), in 36/37 (S: 97.3%) of smear-positive samples and in 6/10 (S: 60%) of concentrate samples sputum. The intensity of positive smear microscopy had a direct relationship with the sensitivity of spoligotyping. DISCUSSION: This study combined the potential of a molecular epidemiology tool to analyse DNA from sputum samples in smears acid fast staining, it visualizes diagnosis and genotyping platform in developing countries gathering innovation and high sensitivity in the hibridization of specific olignonucleotides from positive smears (P+, P++, P+++). However, the low specificity showed the need to improve better agreement among genetic patterns compared to the standardized bacterial isolation from M. tuberculosis strains.