Mapping Antibody Domain Exposure on Nanoparticle Surfaces Using DNA-PAINT

Decorating nanoparticles with antibodies (Ab) is a key strategy for targeted drug delivery and imaging. For this purpose, the orientation of the antibody on the nanoparticle is crucial to maximize fragment antibody-binding (Fab) exposure and thus antigen binding. Moreover, the exposure of the fragment crystallizable (Fc) domain may lead to the engagement of immune cells through one of the Fc receptors. Therefore, the choice of the chemistry for nanoparticle-antibody conjugation is key for the biological performance, and methods have been developed for orientation-selective functionalization. Despite the importance of this issue, there is a lack of direct methods to quantify the antibodies' orientation on the nanoparticle's surface. Here, we present a generic methodology that enables for multiplexed, simultaneous imaging of both Fab and Fc exposure on the surface of nanoparticles, based on super-resolution microscopy. Fab-specific Protein M and Fc-specific Protein G probes were conjugated to single stranded DNAs and two-color DNA-PAINT imaging was performed. Hereby, we quantitatively addressed the number of sites per particle and highlight the heterogeneity in the Ab orientation and compared the results with a geometrical computational model to validate data interpretation. Moreover, super-resolution microscopy can resolve particle size, allowing the study of how particle dimensions affect antibody coverage. We show that different conjugation strategies modulate the Fab and Fc exposure which can be tuned depending on the application of choice. Finally, we explored the biomedical importance of antibody domain exposure in antibody dependent cell mediated phagocytosis (ADCP). This method can be used universally to characterize antibody-conjugated nanoparticles, improving the understanding of relationships between structure and targeting capacities in targeted nanomedicine.

Extracellular vesicles secreted by triple-negative breast cancer stem cells trigger premetastatic niche remodeling and metastatic growth in the lungs

Tumor secreted extracellular vesicles (EVs) are potent intercellular signaling platforms. They are responsible for the accommodation of the premetastatic niche (PMN) to support cancer cell engraftment and metastatic growth. However, complex cancer cell composition within the tumor increases also the heterogeneity among cancer secreted EVs subsets, a functional diversity that has been poorly explored. This phenomenon is particularly relevant in highly plastic and heterogenous triple-negative breast cancer (TNBC), in which a significant representation of malignant cancer stem cells (CSCs) is displayed. Herein, we selectively isolated and characterized EVs from CSC or differentiated cancer cells (DCC; EVs^CSC and EVs^DCC , respectively) from the MDA-MB-231 TNBC cell line. Our results showed that EVs^CSC and EVs^DCC contain distinct bioactive cargos and therefore elicit a differential effect on stromal cells in the TME. Specifically, EVs^DCC activated secretory cancer associated fibroblasts (CAFs), triggering IL-6/IL-8 signaling and sustaining CSC phenotype maintenance. Complementarily, EVs^CSC promoted the activation of α-SMA+ myofibroblastic CAFs subpopulations and increased the endothelial remodeling, enhancing the invasive potential of TNBC cells in vitro and in vivo. In addition, solely the EVs^CSC mediated signaling prompted the transformation of healthy lungs into receptive niches able to support metastatic growth of breast cancer cells.

Precision and Accuracy of Receptor Quantification on Synthetic and Biological Surfaces Using DNA-PAINT

Characterization of the number and distribution of biological molecules on 2D surfaces is of foremost importance in biology and biomedicine. Synthetic surfaces bearing recognition motifs are a cornerstone of biosensors, while receptors on the cell surface are critical/vital targets for the treatment of diseases. However, the techniques used to quantify their abundance are qualitative or semi-quantitative and usually lack sensitivity, accuracy, or precision. Detailed herein a simple and versatile workflow based on super-resolution microscopy (DNA-PAINT) was standardized to improve the quantification of the density and distribution of molecules on synthetic substrates and cell membranes. A detailed analysis of accuracy and precision of receptor quantification is presented, based on simulated and experimental data. We demonstrate enhanced accuracy and sensitivity by filtering out non-specific interactions and artifacts. While optimizing the workflow to provide faithful counting over a broad range of receptor densities. We validated the workflow by specifically quantifying the density of docking strands on a synthetic sensor surface and the densities of PD1 and EGF receptors (EGFR) on two cellular models.

Complex pBAE nanoparticles cell trafficking: tracking both position and composition using super resolution microscopy

Nanomedicine emerged some decades ago with the hope to be the solution for most unmet medical needs. However, tracking materials at nanoscale is challenging to their reduced size, below the resolution limit of most conventional techniques. In this context, we propose the use of direct stochastic optical reconstruction microscopy (dSTORM) to study time stability and cell trafficking after transfection of oligopeptide end‐modified poly(β‐aminoester) (OM‐pBAE) nanoparticles. We selected different combinations of cationic end oligopeptides (arginine – R; histidine – H; and lysine – K) among polymer libraries, since the oligopeptide combination demonstrated to be useful for different applications, such as vaccination and gene silencing. We demonstrate that their time evolution as well as their cell uptake and trafficking are dependent on the oligopeptide. This study opens the pave to broad mechanistic studies at nanoscale that could enable a rational selection of specific pBAE nanoparticles composition after determining their stability and cell trafficking.

Extracellular vesicles from recombinant cell factories improve the activity and efficacy of enzymes defective in lysosomal storage disorders

In the present study the use of extracellular vesicles (EVs) as vehicles for therapeutic enzymes in lysosomal storage disorders was explored. EVs were isolated from mammalian cells overexpressing alpha-galactosidase A (GLA) or N-sulfoglucosamine sulfohydrolase (SGSH) enzymes, defective in Fabry and Sanfilippo A diseases, respectively. Direct purification of EVs from cell supernatants was found to be a simple and efficient method to obtain highly active GLA and SGSH proteins, even after EV lyophilization. Likewise, EVs carrying GLA (EV-GLA) were rapidly uptaken and reached the lysosomes in cellular models of Fabry disease, restoring lysosomal functionality much more efficiently than the recombinant enzyme in clinical use. In vivo, EVs were well tolerated and distributed among all main organs, including the brain. DiR-labelled EVs were localized in brain parenchyma 1 h after intra-arterial (internal carotid artery) or intravenous (tail vein) administrations. Moreover, a single intravenous administration of EV-GLA was able to reduce globotriaosylceramide (Gb3) substrate levels in clinically relevant tissues, such kidneys and brain. Overall, our results demonstrate that EVs from cells overexpressing lysosomal enzymes act as natural protein delivery systems, improving the activity and the efficacy of the recombinant proteins and facilitating their access to organs neglected by conventional enzyme replacement therapies.

Nanoscopy for endosomal escape quantification

The successful cytosolic delivery of nanoparticles is hampered by their endosomal entrapment and degradation. To push forward the smart development of nanoparticles we must reliably detect and quantify their endosomal escape process. However, the current methods employed are not quantitative enough at the nanoscale to achieve this. Nanoscopy is a rapidly evolving field that has developed a diverse set of powerful techniques in the last two decades, opening the door to explore nanomedicine with an unprecedented resolution and specificity. The understanding of key steps in the drug delivery process - such as endosomal escape - would benefit greatly from the implementation of the most recent advances in microscopy. In this review, we provide the latest insights into endosomal escape of nanoparticles obtained by nanoscopy, and we discuss the features that would allow these techniques to make a great impact in the field.

Island effect in the shell phenotypic plasticity of an intertidal gastropod

The pattern of shell shape variation in populations of the top shell, Phorcus sauciatus from Madeira Island (NE Atlantic) was analysed as a function of substrate type and wave exposure, using geometric morphometrics. We hypothesized that P. sauciatus shows morphological variations to inhabit contrasting environments. Highly significant differences in shell shape were found depending on both substrate type and coastal exposure. The most marked differences were found between exposed and sheltered environments. Rounded shells in exposed environments may be explained by physiological reasons, since larger muscles are needed to ensure attachment to substrate in areas subject to harsh conditions. On the other side, conically-shaped shells may accommodate a larger body but with a smaller foot, an adaptation to sheltered environments. Slight shape variations were also observed among substrates, mostly in the degree of differentiation of some whorls. Differences could be related to a particular use of habitat and/or to the degree of exposure to water current. These results suggest that P. sauciatus is locally adapted to varying coastal hydrodynamics and may be considered as a good model in studies on adaptations of fauna to certain climate change effects.

Tracking the DNA complexation state of pBAE polyplexes in cells with super resolution microscopy

The future of gene therapy relies on the development of efficient and safe delivery vectors. Poly(β-amino ester)s are promising cationic polymers capable of condensing oligonucleotides into nanoparticles - polyplexes - and deliver them into the cell nucleus, where the gene material would be expressed. The complexation state during the crossing of biological barriers is crucial: polymers should tightly complex DNA before internalization and then release to allow free DNA to reach the nucleus. However, measuring the complexation state in cells is challenging due to the nanometric size of polyplexes and the difficulties to study the two components (polymer and DNA) independently. Here we propose a method to visualize and quantify the two components of a polyplex inside cells, with nanometre scale resolution, using two-colour direct stochastic reconstruction super-resolution microscopy (dSTORM). With our approach, we tracked the complexation state of pBAE polyplexes from cell binding to DNA release and nuclear entry revealing time evolution and the final fate of DNA and pBAE polymers in mammalian cells.

Vertical zonation and functional diversity of fish assemblages revealed by ROV videos at oil platforms in The Gulf

An assessment of vertical distribution, diel migration, taxonomic and functional diversity of fishes was carried out at offshore platforms in The (Arabian-Iranian-Persian) Gulf. Video footage was recorded at the Al Shaheen oil field between 2007 and 2014 using a remotely operated vehicle (ROV). A total of 12 822 individual fishes, from 83 taxonomic groups were recorded around the platforms. All the species identified are considered native to The Gulf, although Cyclichthys orbicularis and Lutjanus indicus were recorded for the first time in Qatari waters. Several trends were uncovered in the vertical distribution of the fish community; most species were observed between 20 and 50 m depth and fish abundance decreased towards the bottom, with the highest abundances recorded in the upper layers, i.e. down to 40 m depth. Vertical variation in fish diversity, however, was generally not accompanied by differences in vertical movements. Carnivores and invertivores were the dominant trophic groups, being found at each depth range from surface to seabed. The functional indices showed no significant differences between water depths or diel cycles. The study demonstrates that oil platforms represent a hotspot of fish diversity and interesting sites for studying fish communities, abundance and behaviour.

Estados electrónicos para un cascarón cuántico semiconductor de geometría cilíndrica

En este trabajo obtenemos los estados electrónicos para un cascarón cuántico semiconductor de geometría cilíndrica obtenido a partir de una matriz de . En este caso hemos asumido que el sistema solo tiene una banda la cual se desdobla en un sistema de sub-bandas debido al confinamiento. Utilizando el formalismo de la masa efectiva determinamos las funciones de onda y las energías de los estados.

Treatment for agenesis of maxillary lateral incisors: a systematic review

OBJECTIVES

To compare the efficacy and safety of three orthodontic treatment modalities for agenesis of maxillary lateral incisors: 1) closing the space with the reshaped canine substituting the lateral incisor, 2) opening the space with placement of a conventional fixed bridge, and 3) opening the space with placement of a single-unit implant and an implant-supported crown.

SETTING

Brazilian Cochrane Center and Universidade Federal de São Paulo, Brazil.

MATERIAL AND METHODS

The following databases were investigated: Cochrane Register of Controlled Trials (Edition 12, 2011), EMBASE (from 1974 to December 2011), MEDLINE (from 1965 to December 2011), LILACS (from 1966 to November 2011), and Odontology Brazilian Bibliography Database (from 1966 to November 2011). Conference abstracts, main Brazilian dissertations and theses databases, and reference lists were handsearched. This systematic review included randomized or quasi-randomized controlled trials (RCTs) including women aged 15 years or over and men aged 21 years or over who received one of the interventions stated above. Two observers independently evaluated all the studies regarding eligibility criteria and assessed the risk of bias of included studies.

RESULTS

No studies were included in the review as no RCTs were found. Most of the evidence comes from case reports and narrative reviews on case reports and from three studies with a single post-intervention evaluation and non-comparable control groups with high risk of bias.

CONCLUSIONS

There is no scientific evidence for any of the three most common types of treatment for agenesis of the maxillary lateral incisors. RCTs into this issue are still necessary.

Arbitrary-order corrections for finite-time drift and diffusion coefficients

We address a standard class of diffusion processes with linear drift and quadratic diffusion coefficients. These contributions to dynamic equations can be directly drawn from data time series. However, real data are constrained to finite sampling rates and therefore it is crucial to establish a suitable mathematical description of the required finite-time corrections. Based on Itô-Taylor expansions, we present the exact corrections to the finite-time drift and diffusion coefficients. These results allow to reconstruct the real hidden coefficients from the empirical estimates. We also derive higher-order finite-time expressions for the third and fourth conditional moments that furnish extra theoretical checks for this class of diffusion models. The analytical predictions are compared with the numerical outcomes of representative artificial time series.

[Diagnosis and therapeutical management offered to rheumatoid arthritis patients in Brazil--rheumatologists' answers from an assessment questionnaire]

OBJECTIVES

The aim of this study was to evaluate in relation to diagnosis and treatment for Rheumatoid Arthritis (RA) patients Brazilian population, and compare the management offered to patients who are followed up in the public and private sectors.

MATERIAL AND METHODS

An electronic questionnaire was sent to 650 rheumatologists, members of the Brazilian Rheumatology Society (SBR) and who were attending adult RA patients in the public and/or private sector, who had a contact e-mail address available in the SBR register and agreed to take part in the survey.

RESULTS

The rheumatologists estimated that 51.7% of the patients had had their disease diagnosed and of these, 56.1% were undergoing treatment. It was also estimated that 53.9% of the RA patients that was under treatment were being followed up by rheumatologists. The mean time interval estimated by the rheumatologists, between the appearance of the first symptoms of RA and the diagnosis made by a doctor, was greater among the patients who sought attendance in public services (1.8 years). There was no difference in clinical and radiographic assessment measures between the two types of service, with the exception of the application of HAQ, which was used more in public services. The principal drug association reported in both types of services was methotrexate and chloroquine. The rate of usage of associations between biological agents and methotrexate ranged from 6 to 8%. The main treatment-related difficulties were: access to the health system (public services) and cost of medication (private services).

CONCLUSION

Approximately 50% of RA patients are being diagnosed and half of these are under treatment. There was no great difference in attendance within the public and private systems for these patients, whereas the main difficulty for the public system was access to attendance, for the private system it was the cost of the medication.

Additive-multiplicative stochastic models of financial mean-reverting processes

We investigate a generalized stochastic model with the property known as mean reversion, that is, the tendency to relax towards a historical reference level. Besides this property, the dynamics is driven by multiplicative and additive Wiener processes. While the former is modulated by the internal behavior of the system, the latter is purely exogenous. We focus on the stochastic dynamics of volatilities, but our model may also be suitable for other financial random variables exhibiting the mean reversion property. The generalized model contains, as particular cases, many early approaches in the literature of volatilities or, more generally, of mean-reverting financial processes. We analyze the long-time probability density function associated to the model defined through an Itô-Langevin equation. We obtain a rich spectrum of shapes for the probability function according to the model parameters. We show that additive-multiplicative processes provide realistic models to describe empirical distributions, for the whole range of data.

Thrombotic pulmonary arteriopathy in polycythemia vera

Pulmonary infarction and hemorrhage are important differential diagnoses in pulmonary coin lesions, especially in patients with underlying hematologic malignancies. We report a 58-year-old female patient suffering from polycythemia vera presenting with multiple pulmonary coin lesions. Open lung biopsy and subsequent histologic investigations showed organized pulmonary infarction and primary pulmonary thrombotic arteriopathy. Although histologic features are non-contributory in distinguishing organized thrombosis from organized thromboembolism, the clinical setting and localization of the lesions suggest that in the present case the vascular lesions are due to organized thrombosis.

Abnormal pattern of tyrosine phosphorylation in unstimulated peripheral blood T lymphocytes from patients with systemic lupus erythematosus

Previous reports have shown abnormal responses mediated via the TCR/CD3 pathway in T lymphocytes from systemic lupus erythematosus (SLE) patients. Recently, we and others have reported augmented TCR/CD3-mediated responses in lupus T cells. It is possible that the pattern of downstream biochemical signals triggered by TCR/CD3 ligation may be altered in T lymphocytes from patients with SLE, thus leading to abnormal distal cell responses. In this paper we have examined the phosphorylation of proteins on tyrosine residues in peripheral blood T lymphocytes from a group of SLE patients and controls. We found a lower frequency of constitutively tyrosine-phosphorylated 119- and 113-kDa substrates and an enhanced frequency of tyrosine-phosphorylated 66- and 25-kDa proteins in unstimulated cultures of SLE T lymphocytes, suggesting an altered pattern of tyrosine phosphorylation in T cells from patients in vivo. Additionally, the protein tyrosine phosphatase (PTP) activity of CD45 immunoprecipitates was lower in unstimulated lupus T cells and was enhanced after stimulation via the CD3 pathway in lupus but not control T lymphocytes. The present results seem to suggest abnormal regulation of in-vivo tyrosine phosphorylation in T cells from patients with SLE.

[Hydatid cyst in the hepatic hilum causing a cavernous transformation in the portal vein]

Portal cavernomatosis consists in the substitution of the portal vein by many fine, twisting venules leading to the liver. This phenomenon is produced as a consequence of anterior thrombosis of the portal vein and is associated with chronic pancreatitis, cancer of the pancreas, intraabdominal sepsis and cholelithiasis. The symptomatology may be nul or present as obstructive jaundice or portal hypertension. Diagnosis is made by Doppler echography. The treatment is portal shunt when symptomatology is produced. In patients with cholelithiasis requiring surgery, the shunt is advised prior to biliary surgery since perioperative hemorrhage, if present, may be incoercible as in the case herein described. We present a 84-year-old woman with portal cavernomatosis the etiology of which was a hydatidic cyst located in the hepatic bifurcation and treated with mebendazol 10 years previously. This etiology has not been previously reported.

Massive cerebral calcifications associated with increased renal phosphate reabsorption

Extensive bilateral cerebral cortical calcifications were demonstrated in a young patient with a history of convulsions since the age of 4 years. Initial metabolic workup showed normal serum calcium levels, hyperphosphatemia, normal renal function, low urinary calcium excretion, and normal serum immunoreactive parathyroid hormone levels. The intravenous infusion of edetate disodium (disodium EDTA) showed a normal phosphaturic and cyclic adenosine monophosphate response, ruling out the diagnosis of pseudohypoparathyroidism. The infusion of acetazolamide produced a blunted phosphaturia with almost no change in the renal phosphorus threshold, suggesting a tubular defect that allows enhanced proximal tubular reabsorption of phosphorus. Although the exact mechanisms responsible for the localized calcifications remain obscure, we suggest that an enhanced proximal tubular reabsorption of phosphorus could be involved in the pathophysiologic basis of this abnormality.

Orciprenaline and fetal lung maturation in rabbits

The palmitic and stearic acids and the palmitic/stearic ratio in fetal rabbit lungs were studied after orciprenaline administration to the mother from the 26th to the 31st day of gestation. The results were significantly higher in the treated groups than in the control group for the palmitic acid and palmitic/stearic ratio.

The use of urokinase in acute myocardial infarction: report of two cases

In the course of a study (now including 53 patients) on the effectiveness of urokinase in the treatment of acute coronary occlusion, coronary angiography was performed in 2 patients before and after the use of this drug. In both instances the angiograms demonstrated obstruction in the coronary-artery branches, with additional narrowing and some collateral circulation. After urokinase therapy, blood flow was restored in the areas previously obstructed. These 2 case reports are presented because they demonstrate this favorable change in coronary blood flow in association with this particular form of therapy. It is hoped that the completed urokinase study may add some information concerning the effect of thrombolysis in the management of myocardial infarction.