Placental transfer dynamics and durability of maternal COVID-19 vaccine-induced antibodies in infants.

Completion of a COVID-19 vaccination series during pregnancy effectively reduces COVID-19 hospitalization among infants less than 6 months of age. The dynamics of transplacental transfer of maternal vaccine-induced antibodies, and their persistence in infants at 2, 6, 9, and 12 months, have implications for new vaccine development and optimal timing of vaccine administration in pregnancy. We evaluated anti-COVID antibody IgG subclass, Fc-receptor binding profile, and activity against wild-type Spike and RBD plus five variants of concern (VOCs) in 153 serum samples from 100 infants. Maternal IgG1 and IgG3 responses persisted in 2- and 6-month infants to a greater extent than the other IgG subclasses, with high persistence of antibodies binding placental neonatal Fc-receptor and FcγR3A. Lowest persistence was observed against the Omicron RBD-specific region. Maternal vaccine timing, placental Fc-receptor binding capabilities, antibody subclass, fetal sex, and VOC all impact the persistence of antibodies in infants through 12 months of age.

What facilitates or prevents academic fraud in a Colombian faculty of medicine-Protocol of a study using fuzzy cognitive mapping.

INTRODUCTION: Academic fraud is any behavior that gives a student an undeserved advantage over another student. Few studies have explored the causes of and possible solutions to academic fraud in Latin America. We aim to map the knowledge of stakeholders in a Colombian faculty of medicine about the factors that facilitate and prevent academic fraud. METHODS: Fuzzy cognitive mapping. We will use the approach proposed by Andersson and Silver to generate fuzzy cognitive maps representing stakeholder knowledge. This process consists of ten steps: (1) definition of the research question; (2) identification of participants; (3) generation of ideas; (4) rationalization of ideas; (5) organization and connection of ideas; (6) weighing; (7) pattern grouping; (8) list of links and digitization; (9) combination of maps and network analysis; and (10) deliberative dialogue. To draw the maps, we will invite medical students, interns, resident physicians, master's students, and professors in the faculty of medicine. Four medical students will receive training to facilitate the sessions. Participants will identify the factors contributing to academic fraud and their causal relationships. We will use a combination of network analysis and graph theory to identify the chains of factors with greatest influence on academic fraud. CONCLUSION: The maps will serve to discuss strategies to reduce academic fraud in the Faculty of Medicine and to identify factors that could be addressed in other contexts with similar problems. This research will allow the students who facilitate mapping sessions to learn about research techniques, fuzzy cognitive mapping and academic fraud. Study registration: Registered in OSF Registries on August 2nd, 2022. Registration number: osf.io/v4amz.

Efficient quenching sheds light on early stages of gold nanoparticle formation.

The formation mechanism of plasmonic gold nanoparticles (Au NPs) by fast NaBH4 induced reduction of the precursors is still under debate. In this work we introduce a simple method to access intermediate species of Au NPs by quenching the solid formation process at desired time periods. In this way, we take advantage of the covalent binding of glutathione on Au NPs to stop their growth. By applying a plethora of precise particle characterization techniques, we shed new light on the early stages of particle formation. The results of in situ UV/vis measurements, ex situ sedimentation coefficient analysis by analytical ultracentrifugation, size exclusion high performance liquid chromatography, electrospray ionization mass spectrometry supported by mobility classification and scanning transmission electron microscopy suggest an initial rapid formation of small non-plasmonic Au clusters with Au10 as the main species followed by their growth to plasmonic Au NPs by agglomeration. The fast reduction of gold salts by NaBH4 depends on mixing which is hard to control during the scale-up of batch processes. Thus, we transferred the Au NP synthesis to a continuous flow process with improved mixing. We observed that the mean volume particle sizes and the width of the particle size distribution decrease with increasing flow rate and thus higher energy input. Mixing- and reaction-controlled regimes are identified.

Understanding Barriers and Facilitators of Attention-Deficit/Hyperactivity Disorder Treatment Initiation and Adherence in Black and Latinx Children.

OBJECTIVE: Despite evidence that consistent treatment is important for Attention-Deficit/Hyperactivity Disorder (ADHD) management, ADHD treatment initiation and adherence remains suboptimal in minoritized children. The goal of this study was to explore barriers and facilitators to ADHD treatment initiation/adherence for minoritized children to further inform development of our family navigation intervention. METHODS: Using a virtual platform, we completed 7 focus group sessions (total n.ß=.ß26) and 6 individual interviews with representatives from 4 stakeholder groups: experienced caregivers of children with ADHD, caregivers of children newly diagnosed with ADHD, family navigators, and clinicians who care for children with ADHD. All caregivers identified as Black and/or Latinx. Separate sessions were conducted for each stakeholder group and caregivers had the option to attend an English or Spanish session. Using a thematic analysis strategy, barriers and facilitators to ADHD treatment initiation and/or adherence were coded in focus group/interview data and themes were identified across groups. RESULTS: The primary barriers to ADHD treatment initiation and/or adherence identified for minoritized children were lack of support from school/healthcare/family members, cultural barriers, limited resources, limited access, and treatmentconcerns, with variability in endorsement across participants. Reported facilitators included caretakers having experience with ADHD, strong support, access to resources, andwitnessing their child...s functional improvement with treatment. CONCLUSIONS: Caregiver experience with and knowledge about ADHD, support, and access to resources facilitate ADHD treatment in minoritized children. The results from this study have the potential to improve ADHD treatment initiation/adherence and outcomes for minoritized children through the development of culturally tailored, multipronged interventions.

Educational games created by medical students in a cultural safety training game jam: a qualitative descriptive study.

BACKGROUND: Cultural safety training, whereby health professionals learn to reflect on their own culture and to respect the cultural identity of patients, could address intercultural tensions in health care. Given the context of their medical education, however, medical students might perceive such training to be dull or even unnecessary. Game jams, collaborative workshops to create and play games, are a potentially engaging learning environment for medical students today. How medical students learn while making games is poorly documented. This study describes the characteristics of educational games created by participants in a cultural safety game jam and the concepts they used to create games. METHODS: As part of a trial, 268 Colombian medical students divided into 48 groups participated in an eight-hour game jam to create a prototype of an educational game on cultural safety. In this qualitative descriptive study, we reviewed the description of the games uploaded by participants, including the name, objective, game narrative, rules, rewards, penalties, and pictures. An inductive thematic analysis collated their descriptions. RESULTS: The game descriptions illustrated the characteristics of the educational games and the aspects of the cultural safety concept that the students used to create games. Medical students situated cultural safety within a continuum with culturally unsafe actions at one end and cultural safety at the other end. Although not familiar with game design, the students designed prototypes of basic educational games including game dynamics, game scenarios, learning objectives, and pedagogical strategies. CONCLUSION: The findings of this study could help researchers and educators to understand how medical students learn from game design and the kind of games that game jam participants can create without previous game design skills.

Single-Chain Fragment Variable: Recent Progress in Cancer Diagnosis and Therapy.

Cancer remains a public health problem worldwide. Although conventional therapies have led to some excellent outcomes, some patients fail to respond to treatment, they have few therapeutic alternatives and a poor survival prognosis. Several strategies have been proposed to overcome this issue. The most recent approach is immunotherapy, particularly the use of recombinant antibodies and their derivatives, such as the single-chain fragment variable (scFv) containing the complete antigen-binding domains of a whole antibody that successfully targets tumor cells. This review describes the recent progress made with scFvs as a cancer diagnostic and therapeutic tool, with an emphasis on preclinical approaches and their potential use in clinical trials.

Recombinant Attenuated Salmonella enterica as a Delivery System of Heterologous Molecules in Cancer Therapy.

Over a century ago, bacterial extracts were found to be useful in cancer therapy, but this treatment modality was obviated for decades. Currently, in spite of the development and advances in chemotherapies and radiotherapy, failure of these conventional treatments still represents a major issue in the complete eradication of tumor cells and has led to renewed approaches with bacteria-based tumor therapy as an alternative treatment. In this context, live-attenuated bacteria, particularly Salmonella enterica, have demonstrated tumor selectivity, intrinsic oncolytic activity, and the ability to induce innate or specific antitumor immune responses. Moreover, Salmonella enterica also has strong potential as a delivery system of tumor-associated antigens, cytotoxic molecules, immunomodulatory molecules, pro-apoptotic proteins, and nucleic acids into eukaryotic cells, in a process known as bactofection and antitumor nanoparticles. In this review, we present the state of the art of current preclinical and clinical research on the use of Salmonella enterica as a potential therapeutic ally in the war against cancer.

The most significant change for Colombian medical trainees going transformative learning on cultural safety: qualitative results from a randomised controlled trial.

BACKGROUND: Cultural safety training is not yet standard in Colombian medical education. If incorporated, it could address currently adversarial interactions between health professionals and the 40% of people who use traditional medicine practices. In 2019, a randomised controlled trial tested the impact of cultural safety training for medical students using participatory serious game design. The quantitative evaluation showed improved cultural safety intentions of Colombian medical trainees. We report here a qualitative evaluation of the most significant change perceived by trial participants. METHODS: This qualitative descriptive study used the most significant change technique. We invited the trial participants engaged in clinical settings to describe stories of change in their supervised clinical practice that they attributed to the intervention. Using a deductive thematic analysis based on a modified theory of planned behaviour, two independent reviewers coded the stories and, by consensus, created themes and sub-themes. RESULTS: From 27 stories of change, we identified seven themes and 15 subthemes: (a) Conscious knowledge: benefits of cultural safety training, consequences of culturally unsafe behaviour, cultural diversity and cultural practices; (b) Attitudes: respect and appreciation for cultural diversity, openness, and self-awareness; (c) Subjective norms: positive perception of cultural practices and less ethnocentrism; (d) Intention to Change; (e) Agency to accept cultural diversity and to prevent culturally unsafe actions; (f) Discussion; and (g) Action: better communication and relationship with patients and peers, improved outcomes for patients, physicians, and society, investigation about cultural health practices, and efforts to integrate modern medicine and cultural health practices. CONCLUSION: The narratives illustrated the transformative impact of cultural safety training on a results chain from conscious knowledge through to action. Our results encourage medical educators to report other cultural safety training experiences, ideally using patient-related outcomes or direct observation of medical trainees in clinical practice. TRIAL REGISTRATION: Registered on ISRCTN registry on 18/07/2019. REGISTRATION NUMBER: ISRCTN14261595.

Mucosal Vaccination: A Promising Alternative Against Flaviviruses.

The Flaviviridae are a family of positive-sense, single-stranded RNA enveloped viruses, and their members belong to a single genus, Flavivirus. Flaviviruses are found in mosquitoes and ticks; they are etiological agents of: dengue fever, Japanese encephalitis, West Nile virus infection, Zika virus infection, tick-borne encephalitis, and yellow fever, among others. Only a few flavivirus vaccines have been licensed for use in humans: yellow fever, dengue fever, Japanese encephalitis, tick-borne encephalitis, and Kyasanur forest disease. However, improvement is necessary in vaccination strategies and in understanding of the immunological mechanisms involved either in the infection or after vaccination. This is especially important in dengue, due to the immunological complexity of its four serotypes, cross-reactive responses, antibody-dependent enhancement, and immunological interference. In this context, mucosal vaccines represent a promising alternative against flaviviruses. Mucosal vaccination has several advantages, as inducing long-term protective immunity in both mucosal and parenteral tissues. It constitutes a friendly route of antigen administration because it is needle-free and allows for a variety of antigen delivery systems. This has promoted the development of several ways to stimulate immunity through the direct administration of antigens (e.g., inactivated virus, attenuated virus, subunits, and DNA), non-replicating vectors (e.g., nanoparticles, liposomes, bacterial ghosts, and defective-replication viral vectors), and replicating vectors (e.g., Salmonella enterica, Lactococcus lactis, Saccharomyces cerevisiae, and viral vectors). Because of these characteristics, mucosal vaccination has been explored for immunoprophylaxis against pathogens that enter the host through mucosae or parenteral areas. It is suitable against flaviviruses because this type of immunization can stimulate the parenteral responses required after bites from flavivirus-infected insects. This review focuses on the advantages of mucosal vaccine candidates against the most relevant flaviviruses in either humans or animals, providing supporting data on the feasibility of this administration route for future clinical trials.

Egr1 is a 3D matrix-specific mediator of mechanosensitive stem cell lineage commitment.

While extracellular matrix (ECM) mechanics strongly regulate stem cell commitment, the field's mechanistic understanding of this phenomenon largely derives from simplified two-dimensional (2D) culture substrates. Here, we found a 3D matrix-specific mechanoresponsive mechanism for neural stem cell (NSC) differentiation. NSC lineage commitment in 3D is maximally stiffness sensitive in the range of 0.1 to 1.2 kPa, a narrower and more brain-mimetic range than we had previously identified in 2D (0.75 to 75 kPa). Transcriptomics revealed stiffness-dependent up-regulation of early growth response 1 (Egr1) in 3D but not in 2D. Egr1 knockdown enhanced neurogenesis in stiff ECMs by driving ß-catenin nuclear localization and activity in 3D, but not in 2D. Mechanical modeling and experimental studies under osmotic pressure indicate that stiff 3D ECMs are likely to stimulate Egr1 via increases in confining stress during cell volumetric growth. To our knowledge, Egr1 represents the first 3D-specific stem cell mechanoregulatory factor.

Determination of the yield, mass and structure of silver patches on colloidal silica using multiwavelength analytical ultracentrifugation.

Anisotropic nanoparticles offer considerable promise for applications but also present significant challenges in terms of their characterization. Recent developments in the electroless deposition of silver patches directly onto colloidal silica particles have opened up a simple and scalable synthesis method for patchy particles with tunable optical properties. Due to the reliance on patch nucleation and growth, however, the resulting coatings are distributed in coverage and thickness and some core particles remain uncoated. To support process optimization, new methods are required to rapidly determine patch yield, thickness and coverage. Here we present a novel approach based on multiwavelength analytical ultracentrifugation (MWL-AUC) which permits simultaneous hydrodynamic and spectroscopic characterization. The patchy particle colloids are produced in a continuous flow mixing process that makes use of a KM-type micromixer. By varying the process flow rate or metal precursor concentration we show how the silver to silica mass ratio distribution derived from the AUC-measured sedimentation coefficient distribution can be influenced. Moreover, through reasoned assumptions we arrive at an estimation of the patch yield that is close to that determined by arduous analysis of scanning electron microscopy (SEM) images. Finally, combining MWL-AUC, electrodynamic simulations and SEM image analysis we establish a procedure to estimate the patch thickness and coverage.

A Qualitative Study on Noncommunicable Diseases in Waste Pickers in Brazil.

BACKGROUND: Noncommunicable chronic diseases are associated with multiple risks factors and negative outcomes that are long-lasting and difficult to treat. Some populations may be at greater risk because of their socioeconomic status, lack of healthcare, environment, and poor work and living conditions. Informal waste pickers may experience higher levels of chronic diseases and often do not have access to care to manage symptoms. OBJECTIVES: The aim of the present study was to understand the prevalence of chronic diseases in waste pickers, along with perceived associated risks and available treatments. METHODS: A qualitative study was conducted, using interviews with 24 waste pickers who worked at Estrutural dumpsite in Brasilia, Brazil which was historically the second largest open-air dumpsite in the world. RESULTS: Participants believed their commonly experienced chronic diseases were a result of working in the open-air dumpsite. Chronic diseases commonly noted in the interviews included hypertension, chronic pain, respiratory disease, diabetes, and kidney problems. Participants discussed self-medication or prescribed medication used to treat their conditions. Most participants had varying beliefs regarding prevention strategies to reduce disease; some ideas for prevention focused on religion, fate, and God when discussing outcomes related to illnesses. When answering questions regarding ideal working conditions to help prevent diseases, participants responded by expressing a desire for protective gear (e.g. PPE) which could help mitigate hazards associated with the dump. CONCLUSIONS: Recyclable collectors were aware of occupational hazards to which they were exposed and associated noncommunicable chronic diseases but lacked education on the importance of preventive measures and access to healthcare services. The findings of the present study confirm the need to strengthen intersectoral actions to protect and uphold the health rights of this vulnerable population. PARTICIPANT CONSENT: Obtained. ETHICS APPROVAL: This study was approved by the Research and Ethics Committee of the Health School of Brasília University under Opinion n. 1.517.670/2016. COMPETING INTERESTS: The authors declare no competing financial interests.

Adeno-Associated Virus Vector for Central Nervous System Gene Therapy.

The past several years have witnessed significant advances in the development of therapeutic gene delivery for neurological disorders of the central nervous system (CNS). In particular, genome-wide sequencing analysis has deepened our understanding of mutations that underlie many monogenic disorders, which in turn has contributed to clinical advances involving adeno-associated virus (AAV) vector delivery of replacement genes to treat recessive disorders. Moreover, gene therapy has been further bolstered with advances in genome editing tools that allow researchers to silence, repair, and amend endogenous genes. However, despite strong preclinical and clinical progress, challenges remain, including delivery and safety. Here, we discuss advances in AAV engineering, recent developments in cargo design, and translation of these technologies towards clinical progress.

Cell-Permeable Bak BH3 Peptide Induces Chemosensitization of Hematologic Malignant Cells.

Hematologic malignancies such as leukemias and lymphomas are among the leading causes of pediatric cancer death worldwide, and although survival rates have improved with conventional treatments, the development of drug-resistant cancer cells may lead to patient relapse and limited possibilities of a cure. Drug-resistant cancer cells in these hematologic neoplasms are induced by overexpression of the antiapoptotic B-cell lymphoma 2 (Bcl-2) protein families, such as Bcl-XL, Bcl-2, and Mcl-1. We have previously shown that peptides from the BH3 domain of the proapoptotic Bax protein that also belongs to the Bcl-2 family may antagonize the antiapoptotic activity of the Bcl-2 family proteins, restore apoptosis, and induce chemosensitization of tumor cells. Furthermore, cell-permeable Bax BH3 peptides also elicit antitumor activity and extend survival in a murine xenograft model of human B non-Hodgkin's lymphoma. However, the activity of the BH3 peptides of the proapoptotic Bak protein of the Bcl-2 family against these hematologic malignant cells requires further characterization. In this study, we report the ability of the cell-permeable Bak BH3 peptide to restore apoptosis and induce chemosensitization of acute lymphoblastic leukemia and non-Hodgkin's lymphoma cell lines, and this event is enhanced with the coadministration of cell-permeable Bax BH3 peptide and represents an attractive approach to improve the patient outcomes with relapsed or refractory hematological malignant cells.

Physiopathological and diagnostic aspects of cirrhotic cardiomyopathy.

Cirrhotic cardiomyopathy is characterized by the presence of structural and functional cardiac alterations in patients suffering from hepatic cirrhosis, without previously known cardiac causes that may explain it. Clinically, it is characterized by the presence of variable grades of diastolic and systolic dysfunction (SD), alterations in the electric conductance (elongation of corrected QT interval) and inadequate chronotropic response. This pathology has been related to substandard response in the management of patients with portal hypertension and poor outcome after transplant. Even when the first description of this pathology dates back from 1953, it remains a poorly studied and frequently underdiagnosed entity. Echocardiography prevails as a practical diagnostic tool for this pathology since simple measurements as the E/A index can show diastolic dysfunction. SD discloses as a diminished ejection fraction of the left ventricle and the latent forms are detected by echocardiography studies with pharmacological stress. In recent years, new techniques such as the longitudinal strain have been studied and they seem promising for the detection of early alterations.

La miocardiopatía cirrótica se caracteriza por la presencia de alteraciones cardiacas estructurales y funcionales en pacientes con cirrosis hepática, sin que existan otras causas de enfermedad cardiaca. Clínicamente se caracteriza por la presencia de grados variables de disfunción diastólica y sistólica, alteraciones de la conducción eléctrica (prolongación del intervalo QT) y respuesta cronotrópica inapropiada. Esta patología se ha relacionado con desenlaces clínicos adversos, mala respuesta en el manejo de la hipertensión portal y resultados desfavorables posterior a trasplante hepático ortotópico. A pesar de que las primeras descripciones datan de 1953, es una entidad poco estudiada y frecuentemente subdiagnosticada. El ecocardiograma es una herramienta de diagnóstico importante en esta entidad. Mediciones simples como el índice E/A pueden traducir disfunción diastólica. La disfunción sistólica se manifiesta con disminución de la fracción de eyección del ventrículo izquierdo y las formas latentes se detectan mediante estudios de ecocardiografía con estrés farmacológico; en los últimos años se han estudiado otras técnicas como el strain longitudinal, que parecen prometedoras en la detección de alteraciones tempranas.

Physiopathological and diagnostic aspects of cirrhotic cardiomyopathy / Aspectos fisiopatológicos y diagnósticos de la miocardiopatía cirrótica

Abstract Cirrhotic cardiomyopathy is characterized by the presence of structural and functional cardiac alterations in patients suffering from hepatic cirrhosis, without previously known cardiac causes that may explain it. Clinically, it is characterized by the presence of variable grades of diastolic and systolic dysfunction (SD), alterations in the electric conductance (elongation of corrected QT interval) and inadequate chronotropic response. This pathology has been related to substandard response in the management of patients with portal hypertension and poor outcome after transplant. Even when the first description of this pathology dates back from 1953, it remains a poorly studied and frequently underdiagnosed entity. Echocardiography prevails as a practical diagnostic tool for this pathology since simple measurements as the E/A index can show diastolic dysfunction. SD discloses as a diminished ejection fraction of the left ventricle and the latent forms are detected by echocardiography studies with pharmacological stress. In recent years, new techniques such as the longitudinal strain have been studied and they seem promising for the detection of early alterations.

Resumen La miocardiopatía cirrótica se caracteriza por la presencia de alteraciones cardiacas estructurales y funcionales en pacientes con cirrosis hepática, sin que existan otras causas de enfermedad cardiaca. Clínicamente se caracteriza por la presencia de grados variables de disfunción diastólica y sistólica, alteraciones de la conducción eléctrica (prolongación del intervalo QT) y respuesta cronotrópica inapropiada. Esta patología se ha relacionado con desenlaces clínicos adversos, mala respuesta en el manejo de la hipertensión portal y resultados desfavorables posterior a trasplante hepático ortotópico. A pesar de que las primeras descripciones datan de 1953, es una entidad poco estudiada y frecuentemente subdiagnosticada. El ecocardiograma es una herramienta de diagnóstico importante en esta entidad. Mediciones simples como el índice E/A pueden traducir disfunción diastólica. La disfunción sistólica se manifiesta con disminución de la fracción de eyección del ventrículo izquierdo y las formas latentes se detectan mediante estudios de ecocardiografía con estrés farmacológico; en los últimos años se han estudiado otras técnicas como el strain longitudinal, que parecen prometedoras en la detección de alteraciones tempranas.

Physiopathological and diagnostic aspects of cirrhotic cardiomyopathy.

Cirrhotic cardiomyopathy is characterized by the presence of structural and functional cardiac alterations in patients suffering from hepatic cirrhosis, without previously known cardiac causes that may explain it. Clinically, it is characterized by the presence of variable grades of diastolic and systolic dysfunction, alterations in the electric conductance (elongation of corrected QT interval) and inadequate chronotropic response. This pathology has been related to substandard response in the management of patients with portal hypertension and poor outcome after transplant. Even when the first description of this pathology dates back from 1953, it remains a poorly studied and frequently underdiagnosed entity. Echocardiography prevails as a practical diagnostic tool for this pathology since simple measurements as the E/A index can show diastolic dysfunction. Systolic dysfunction discloses as a diminished ejection fraction of the left ventricle and the latent forms are detected by echocardiography studies with pharmacological stress. In recent years new techniques such as the longitudinal strain have been studied and they seem promising for the detection of early alterations.

La miocardiopatía cirrótica se caracteriza por la presencia de alteraciones cardiacas estructurales y funcionales en pacientes con cirrosis hepática, sin que existan otras causas de enfermedad cardiaca. Clínicamente se caracteriza por la presencia de grados variables de disfunción diastólica y sistólica, alteraciones de la conducción eléctrica (prolongación del intervalo QT) y respuesta cronotrópica inapropiada. Esta patología se ha relacionado con desenlaces clínicos adversos, mala respuesta en el manejo de la hipertensión portal y resultados desfavorables posterior a trasplante hepático ortotópico. A pesar de que las primeras descripciones datan de 1953, es una entidad poco estudiada y frecuentemente subdiagnosticada. El ecocardiograma es una herramienta de diagnóstico importante en esta entidad. Mediciones simples como el índice E/A pueden traducir disfunción diastólica. La disfunción sistólica se manifiesta con disminución de la fracción de eyección del ventrículo izquierdo y las formas latentes se detectan mediante estudios de ecocardiografía con estrés farmacológico; en los últimos años se han estudiado otras técnicas como el strain longitudinal, que parecen prometedoras en la detección de alteraciones tempranas.

Live Attenuated Salmonella enterica Expressing and Releasing Cell-Permeable Bax BH3 Peptide Through the MisL Autotransporter System Elicits Antitumor Activity in a Murine Xenograft Model of Human B Non-hodgkin's Lymphoma.

The survival of patients with non-Hodgkin's lymphoma (NHL) has substantially improved with current treatments. Nevertheless, the appearance of drug-resistant cancer cells leads to patient relapse. It is therefore necessary to find new antitumor therapies that can completely eradicate transformed cells. Chemotherapy-resistant cancer cells are characterized by the overexpression of members of the anti-apoptotic B-cell lymphoma 2 (Bcl-2) protein family, such as Bcl-XL, Bcl-2, and Mcl-1. We have recently shown that peptides derived from the BH3 domain of the pro-apoptotic Bax protein may antagonize the anti-apoptotic activity of the Bcl-2 family proteins, restore apoptosis, and induce chemosensitization of tumor cells. In this study, we investigated the feasibility of releasing this peptide into the tumor microenvironment using live attenuated Salmonella enterica, which has proven to be an ally in cancer therapy due to its high affinity for tumor tissue, its ability to activate the innate and adaptive antitumor immune responses, and its potential use as a delivery system of heterologous molecules. Thus, we expressed and released the cell-permeable Bax BH3 peptide from the surface of Salmonella enterica serovar Typhimurium SL3261 through the MisL autotransporter system. We demonstrated that this recombinant bacterium significantly decreased the viability and increased the apoptosis of Ramos cells, a human B NHL cell line. Indeed, the intravenous administration of this recombinant Salmonella enterica elicited antitumor activity and extended survival in a xenograft NHL murine model. This antitumor activity was mediated by apoptosis and an inflammatory response. Our approach may represent an eventual alternative to treat relapsing or refractory NHL.

CRISPR-Cas9-Mediated Genome Editing Increases Lifespan and Improves Motor Deficits in a Huntington's Disease Mouse Model.

Huntington's disease (HD) is a currently incurable and, ultimately, fatal neurodegenerative disorder caused by a CAG trinucleotide repeat expansion within exon 1 of the huntingtin (HTT) gene, which results in the production of a mutant protein that forms inclusions and selectively destroys neurons in the striatum and other adjacent structures. The RNA-guided Cas9 endonuclease from CRISPR-Cas9 systems is a versatile technology for inducing DNA double-strand breaks that can stimulate the introduction of frameshift-inducing mutations and permanently disable mutant gene function. Here, we show that the Cas9 nuclease from Staphylococcus aureus, a small Cas9 ortholog that can be packaged alongside a single guide RNA into a single adeno-associated virus (AAV) vector, can be used to disrupt the expression of the mutant HTT gene in the R6/2 mouse model of HD following its in vivo delivery to the striatum. Specifically, we found that CRISPR-Cas9-mediated disruption of the mutant HTT gene resulted in a ∼50% decrease in neuronal inclusions and significantly improved lifespan and certain motor deficits. These results thus illustrate the potential for CRISPR-Cas9 technology to treat HD and other autosomal dominant neurodegenerative disorders caused by a trinucleotide repeat expansion via in vivo genome editing.

Diffusion-limited dissolution of calcium carbonate in a hydrogel.

In the process of fabricating porous polymers, we use dispersed calcite as a sacrificial solid that generates porosity after dissolution. To do this, we trap calcite particles in a hydrogel, dissolve the particles and dry the hydrogel; here, we describe in detail the dissolution kinetics. We prepare PEGDA [poly(ethylene glycol)-diacrylate] water solutions loaded with micron-sized calcite particles (containing mostly calcium carbonate) up to about 30% volume fraction; these dispersions are photo-polymerized into hydrogels as flat and shallow monoliths with a typical thickness of ≈100 µm and a lateral extent on the order of 1 cm. These soft hydrogels are then soaked into an acidic solution (HCl) which induces the dissolution of the carbonates. The dissolution fronts remain sharp throughout the dissolution and progress inward in a diffusive manner. Such a kinetics is well described numerically using a mean-field diffusion-reaction model where the diffusion of the acid strongly limits the process.