Observation of a correlated free four-neutron system.

A long-standing question in nuclear physics is whether chargeless nuclear systems can exist. To our knowledge, only neutron stars represent near-pure neutron systems, where neutrons are squeezed together by the gravitational force to very high densities. The experimental search for isolated multi-neutron systems has been an ongoing quest for several decades1, with a particular focus on the four-neutron system called the tetraneutron, resulting in only a few indications of its existence so far2-4, leaving the tetraneutron an elusive nuclear system for six decades. Here we report on the observation of a resonance-like structure near threshold in the four-neutron system that is consistent with a quasi-bound tetraneutron state existing for a very short time. The measured energy and width of this state provide a key benchmark for our understanding of the nuclear force. The use of an experimental approach based on a knockout reaction at large momentum transfer with a radioactive high-energy 8He beam was key.

OPTN/SRTR 2020 Annual Data Report: Lung.

For the first time in a decade, both the number of candidates added to the waiting list and the number of lung transplants performed decreased from the year prior; the number of lung donors also declined. This slowing of transplant activities in 2020 was associated with a modest increase in waitlist mortality. The year 2020 was notable for the global outbreak of the COVID-19 pandemic, which undoubtedly influenced all trends noted in lung transplantation. Time to transplant continued to decrease, with a median time to transplant of 1.4 months across all waitlist candidates. Posttransplant survival remained stable, with 89.4% of transplant recipients surviving to 1 year, 74.8% to 3 years, and 61.2% to 5 years.

OPTN/SRTR 2019 Annual Data Report: Lung.

The number of lung transplants performed continues to increase annually and reached an all-time high in 2019, with decreasing waitlist mortality. These trends are attributable to an increasing number of candidates listed for transplant each year and a continuing increase in the number of donors. Despite these favorable trends, 6.4% of lungs recovered for transplant were not transplanted in 2019, and strategies to optimize use of these available organs may reduce the number of waitlist even further. Time to transplant continued to decrease, as over 50% of candidates waited 3 months or less in 2019, yet regional heterogeneity remained despite policy changes intended to improve allocation equity. Small gains continued in posttransplant survival, with 1-year survival at 88.8%; 3 year, 74.4%; 5 year, 59.2%, and 10 year, 33.1 %.

OPTN/SRTR 2018 Annual Data Report: Lung.

The primary goal of US lung allocation policy is to ensure that candidates with the highest risk for mortality receive appropriate access to lung transplant. In 2018, 2562 lung transplants were performed in the US, reflecting a 31% increase over the past 5 years. More candidates are being listed for lung transplant, and the number of donors has increased substantially. Despite an increase of 84 lung transplants in 2018, 365 adult candidates died or became too sick to undergo transplant. In 2018, 24 new child (ages 0-11 years) candidates were added to the lung transplant waiting list. Fifteen lung transplants were performed in recipients aged 0-11 years, three in recipients aged younger than 1 year, two in recipients aged 1-5 years, and ten in recipients aged 6-11 years. Of 27 child candidates removed from the waiting list in 2018, 16 (59.3%) were removed due to undergoing transplant, six (22.2%) due to death, one (3.7%) due to improved condition, and one (3.7%) due to becoming too sick to undergo transplant.

OPTN/SRTR 2017 Annual Data Report: Lung.

Each year since 2012, the number of lung transplants has increased, reflecting an increase in the number of donors, improved use of recovered organs, and more candidates being listed for transplant. However, the need for organs continues to outpace available donors. Despite an increase of 126 donors in 2017, 1360 candidates remained on the waiting list at the end of the year, and 326 patients died or became too sick to undergo transplant. Approximately 14,000 individuals were living with a lung transplant in 2017; 9492 were aged 50 years or older, 4075 were aged 18-49 years, and 408 were aged younger than 18 years.

[Postmenopausal lichen planopilaris also known as fibrosing frontotemporal alopecia Kossard : An evidence-oriented practical guide to treatment from the University of the Saarland, Hair Research Center of the Dr. Rolf M. Schwiete Foundation]. / Postmenopausaler Lichen planopilaris alias fibrosierende frontotemporale Alopezie Kossard : Ein evidenzorientierter "practical guide to treatment" des Haarforschungszentrums der Dr. Rolf M. Schwiete Stiftung an der Universität des Saarlandes.

Postmenopausal lichen planopilaris (PLPP), also known as fibrosing frontotemporal alopecia Kossard (FFAK), is a not uncommon inflammatory scalp disease affecting approximately 5% of patients at specialized hair centers. The overall incidence of sporadic occurrence is believed to be just under 1% in the older, predominantly female, general population. Since the disease is often undiagnosed, it is statistically likely to be underrepresented. It especially occurs in postmenopausal women who are in the 6th and 7th decade of life (90%), but also in about 10% of premenopausal women, and in men it is documented only in isolated cases. The result is a permanent scarring hair loss accentuated at the front hairline with backward movement towards the neck mostly accompanied by a typical loss of the eyebrows. The disease therefore often leads to significant mental distress and social anxiety in those affected. This is the basis for a compelling need to develop evidence-based therapeutic concepts. While numerous retrospective case series have characterized the phenomenology of FFAK very well, to date there are no randomized controlled trials on evidence-based therapy. Here, we present the Homburger Evidence-Oriented Therapy Algorithm, which is oriented along the available case series evidence: It may (1) serve as a therapy guide for practice and (2) can be used as a basis for working out reliable data based on study evidence. The article contains detailed practical information on photo documentation, biopsy and histological processing up to the practical implementation of, for example, intralesional steroid therapy as well as information on selection criteria for suitable systemic therapies.

OPTN/SRTR 2016 Annual Data Report: Lung.

In 2016, 2692 candidates aged 12 years or older were added to the lung transplant waiting list; 2345 transplants were performed, the largest number of any prior year. The median waiting time for listed candidates in 2016 was 2.5 months, and waiting times were shortest for group D candidates. The transplant rate increased to 191.9 transplants per 100 waitlist years in 2016, with a slight decrease in waitlist mortality to 15.1 deaths per 100 waitlist years. Short-term survival continued to improve, with a 6-month death rate of 6.6% and a 1-year death rate of 10.8% among recipients in 2015 compared with 8.0% and 13.3%, respectively, among recipients in 2014. Long-term survival rates remained unchanged; 55.6% of recipients were alive at 5 years. In 2016, 23 new candidates aged 0-11 years were added to the waiting list and 16 lung transplants were performed. Incidence of posttransplant mortality for lung transplant recipients aged 0-11 years who underwent transplant in 2014-2015 was 13.8% at 6 months and 19.6% at 1 year. Changes in waitlist and transplant demographic features continued to evolve following implementation of the revised lung allocation score in 2015. Some early trends that may be attributable to the revised LAS are shorter waiting times, stabilization of the number of group D candidates listed for transplant, and convergence of LAS with lower prevalence of extremely high scores.

The effect of polymer size and charge of molecules on permeation through synovial membrane and accumulation in hyaline articular cartilage.

The treatment of joint related diseases often involves direct intra-articular injections. For rational development of novel delivery systems with extended residence time in the joint, detailed understanding of transport and retention phenomena within the joint is mandatory. This work presents a systematic study on the in vitro permeation, penetration and accumulation of model polymers with differing charges and molecular weights in bovine joint tissue. Permeation experiments with bovine synovial membrane were performed with PEG polymers (6-200 kDa) and methylene blue in customized diffusion chambers. For polyethylene glycol, 2-fold (PEG 6 kDa), 3-fold (PEG 10 kDa) and 13-fold (PEG 35 kDa) retention by the synovial membrane in reference to the small molecule methylene blue was demonstrated. No PEG 200 kDa was found in the acceptor in detectable amounts after 48 h. This showed the potential for a distinct extension of joint residence times by increasing molecular weights. In addition, experiments with bovine cartilage tissue were conducted. The ability for positively charged, high molecular weight chitosans and HEMA-Co-TMAP (HCT) polymers (up to 233 kDa) to distribute throughout the entire cartilage matrix was demonstrated. In contrast, a distribution into cartilage was not observed for neutral PEG polymers (6-200 kDa). Furthermore, the positive charge density of different compounds (chitosan, HEMA-Co-TMAP, methylene blue, MSC C1 (neutral NCE) and MSC D1 (positively charged NCE) was found to correlate with their accumulation in bovine cartilage tissue. In summary, the results offer pre-clinical in vitro data, indicating that the modification of molecular size and charge of a substance has the potential to decelerate its clearance through the synovial membrane and to promote accumulation inside the cartilage matrix.

Nanocarriers for optimizing the balance between interfollicular permeation and follicular uptake of topically applied clobetasol to minimize adverse effects.

The treatment of various hair disorders has become a central focus of good dermatologic patient care as it affects men and women all over the world. For many inflammatory-based scalp diseases, glucocorticoids are an essential part of treatment, even though they are known to cause systemic as well as local adverse effects when applied topically. Therefore, efficient targeting and avoidance of these side effects are of utmost importance. Optimizing the balance between drug release, interfollicular permeation, and follicular uptake may allow minimizing these adverse events and simultaneously improve drug delivery, given that one succeeds in targeting a sustained release formulation to the hair follicle. To test this hypothesis, three types of polymeric nanocarriers (nanospheres, nanocapsules, lipid-core nanocapsules) for the potent glucocorticoid clobetasol propionate (CP) were prepared. They all exhibited a sustained release of drug, as was desired. The particles were formulated as a dispersion and hydrogel and (partially) labeled with Rhodamin B for quantification purposes. Follicular uptake was investigated using the Differential Stripping method and was found highest for nanocapsules in dispersion after application of massage. Moreover, the active ingredient (CP) as well as the nanocarrier (Rhodamin B labeled polymer) recovered in the hair follicle were measured simultaneously, revealing an equivalent uptake of both. In contrast, only negligible amounts of CP could be detected in the hair follicle when applied as free drug in solution or hydrogel, regardless of any massage. Skin permeation experiments using heat-separated human epidermis mounted in Franz Diffusion cells revealed equivalent reduced transdermal permeability for all nanocarriers in comparison to application of the free drug. Combining these results, nanocapsules formulated as an aqueous dispersion and applied by massage appeare to be a good candidate to maximize follicular targeting and minimize drug penetration into the interfollicular epidermis. We conclude that such nanotechnology-based formulations provide a viable strategy for more efficient drug delivery to the hair follicle. Moreover, they present a way to minimize adverse effects of potent glucocorticoids by releasing the drug in a controlled manner and simultaneously decreasing interfollicular permeation, offering an advantage over conventional formulations for inflammatory-based skin/scalp diseases.

Nanoparticle-Based Mucosal Vaccines Targeting Tumor-Associated Antigens to Human Dendritic Cells.

The induction of effective T cell-mediated immune responses is the main objective of vaccination against cancer. T cell responses are initiated by dendritic cells (DCs) as the most potent antigen-presenting cells. Designing vaccines for efficient delivery of tumor antigens to these cells in immunogenic fashion is, therefore, a major task in tumor immunology. In this human-based in vitro study we investigated the suitability of different polymeric nanoparticles (NPs) for delivering the tumor-associated antigen Her2/neu to DCs for induction of T cell responses by mucosal vaccination. The natural polymer chitosan and novel functionalized PLGA-based polymers were used for NP production. All NPs were efficiently taken up by DCs. Her2/neu delivered by NPs was more efficiently processed and presented by DCs than the soluble protein and induced more vigorous CD4+ and CD8+ T cell proliferation, and cytotoxic T cells. Testing the suitability of this platform for mucosal vaccination, NPs were applied to the apical side of an intestinal epithelium model and found to be efficiently transported across the epithelial layer to become available to basolateral DCs. Thus, chitosan and PLGA-based NPs are efficient carriers for delivery of antigens to DCs for induction of T cell-based immunity, and suitable for mucosal vaccine formulations.

Preparation of nanosized coacervates of positive and negative starch derivatives intended for pulmonary delivery of proteins.

Proteins and peptides represent a large fraction of the compounds currently in drug development pipelines. Their application however often depends on the use of carrier systems. Nanoparticles (NPs) are widely used such carrier systems for protein delivery. The aim of this study was to design a new drug delivery system (DDS), prepared under mild conditions in aqueous solution without the requirement of a stabilizer. The biodegradability and biocompatibility of the designed system was explored with a view to specifically determine its potential to facilitate the pulmonary delivery of proteins. As a first step, anionic and cationic water soluble starch-derivatives were synthesized. These starch polymers allowed for NP formation via coacervation, as well as protein loading. Physicochemical characterization of the prepared NPs was then carried out: NPs were found to have a narrow size distribution with an average size ranging from 140 to 350 nm, and a ζ-potential ranging from -10 to -35 mV, depending on the formulation conditions. In a proof of concept study, starch NPs were found to be readily degraded by the human enzyme α-amylase, and showed good biocompatibility with A549 cells after 4 h. Upon nebulization, NPs were seen to be internalized by air-liquid interface cultivated A549 cells as well as 16HBE14o- cells. To evaluate the ability of starch NPs to load proteins of various characteristics, NPs were loaded with four model proteins/peptides possessing different molecular weights and isoelectric points - IgG1, RNAse A, insulin, and vancomycin. The greatest loading was achieved in the case of vancomycin with up to 23% drug loading and 43% encapsulation efficiency, indicating an optimal loading of proteins with an isoelectric point close to the pH of the NP suspension. In conclusion, starch NPs prepared by the developed mild and straightforward technique show potential as a safe platform for pulmonary delivery of proteins and peptides.

Cyclodextrin-based star polymers as a versatile platform for nanochemotherapeutics: Enhanced entrapment and uptake of idarubicin.

A series of cyclodextrin-based star polymers were synthesized using ß-cyclodextrin (CD) as hydrophilic core, methyl methacrylate (MMA) and tert-butyl acrylate (tBA) as hydrophobic arms. Star polymers, either homopolymers or random/block copolymers, showed narrow molecular weight distributions. Grafting hydrophobic arms created CD-based nanoparticles (CD-NPs) in the size range (130-200nm) with narrow PdI <0.15 and slightly negative ζ-potential. Particle surface could be modified with chitosan to impart a positive surface charge. Colloidal stability of CD-NPs was a function of pH as revealed by the pH-titration curves. CD-NPs were used as carrier for the chemotherapeutic drug idarubicin (encapsulation efficiency, EE ∼40%) ensuring prolonged release profile (∼80% after 48h). For cell-based studies, coumarin-6 was encapsulated as a fluorescent marker (EE ∼75%). Uptake studies carried out on A549 and Caco-2 cell lines proved the uptake of coumarin-loaded NPs as a function of time and preferential localization in the cytoplasm. Uptake kinetics revealed no saturation or plateau over 6h. Chitosan-modified NPs showed significantly improved, concentration-dependent cellular uptake. Meanwhile, CD-NPs were non-cytotoxic on both cell lines over the concentration range (0.25-3mg/ml) as studied by MTT and LDH assays. In conclusion, CD star polymers can be considered a versatile platform for a new class of biocompatible nanochemotherapy.

Enhanced uptake and siRNA-mediated knockdown of a biologically relevant gene using cyclodextrin polyrotaxane.

Ideal cationic polymers for siRNA delivery could result in its enhanced cellular internalization, escape from endosomal degradation, and rapid release in cell cytoplasm, to facilitate knockdown of the target gene. In this study, we have investigated the ability of an in-house synthesized cationic polyrotaxane to bind siRNA into nanometric complexes. This polymer, which had earlier shown improved transfection of model siRNA (luciferase), was used to improve the cellular internalization of the siRNA molecule with therapeutic implications. In cellular assays, the polymer enhanced the knockdown of a gene involved in the pathogenesis of tuberculosis, when the nanocomplexes were compared with free siRNA. The efficacy and cellular non-toxicity of this polymer encourage its further exploitation in animal models of tuberculosis and other intracellular bacterial infections.

Statistical comparison of dissolution profiles to predict the bioequivalence of extended release formulations.

Appropriate setting of dissolution specification of extended release (ER) formulations should include precise definition of a multidimensional space of complex definition and interpretation, including limits in dissolution parameters, lag time (t-lag), variability, and goodness of fit. This study aimed to set dissolution specifications of ER by developing drug-specific dissolution profile comparison tests (DPC tests) that are able to detect differences in release profiles between ER formulations that represent a lack of bioequivalence (BE). Dissolution profiles of test formulations were simulated using the Weibull and Hill models. Differential equations based in vivo-in vitro correlation (IVIVC) models were used to simulate plasma concentrations. BE trial simulations were employed to find the formulations likely to be declared bioequivalent and nonbioequivalent (BE space). Customization of DPC tests was made by adjusting the delta of a recently described tolerated difference test (TDT) or the limits of rejection of f2. Drug ka (especially if ka is small), formulation lag time (t-lag), the number of subjects included in the BE studies, and the number of sampled time points in the DPC test were the factors that affected the most these setups of dissolution specifications. Another recently described DPC test, permutation test (PT), showed excellent statistical power. All the formulations declared as similar with PT were also bioequivalent. Similar case-specific studies may support the biowaiving of ER drug formulations based on customized DPC tests.

Budesonide loaded nanoparticles with pH-sensitive coating for improved mucosal targeting in mouse models of inflammatory bowel diseases.

The purpose of this study was to investigate the therapeutic potential of budesonide loaded nanocarriers for the treatment of inflammatory bowel disease (IBD). First, budesonide was encapsulated in poly(lactic-co-glycolic) acid (PLGA) nanoparticles by an oil in water (O/W) emulsion technique. A second batch of the same nanoparticles was additionally coated with a pH-sensitive methyl-methacrylate-copolymer. The particle sizes of the plain and the coated PLGA were 200±10.1nm and ~240±14.7nm, respectively. As could be shown in vitro, the pH-sensitive coating prevented premature drug release at acidic pH and only releases the drug at neutral to slightly alkaline pH. The efficacy of both coated and plain nanoparticle formulations was assessed in different acute and chronic colitis mouse models, also in comparison to an aqueous solution of the drug. The dose was always the same (0.168mg/kg). It was found that delivery by coated PLGA nanoparticles alleviated the induced colitis significantly better than by plain PLGA particles, which was already more effective than treatment with the same dose of the free drug. These data further corroborate the potential of polymeric nanocarriers for targeted drug delivery to the inflamed intestinal mucosa, and that this concept can still be further improved regarding the oral route of administration by implementing pH-dependent drug release characteristics.

Quantification of nanoparticle uptake into hair follicles in pig ear and human forearm.

Drug delivery via the hair follicle (HF) especially with nanoparticles (NP) recently gained attention due to a depot effect and facilitated absorption conditions within the lower HF. With the prospect of transdermal drug delivery, it is of interest to optimize the follicular uptake of NP. In this study, a method was developed to quantify NP uptake into HF and applied in vitro in a pig ear model and in vivo in human volunteers. The influence of NP material on HF uptake was investigated using fluorescence-labeled NP based on poly(D,L-lactide-co-glycolide) (PLGA). All NP had similar hydrodynamic sizes (163-170 nm) but different surface modifications: (i) plain PLGA, (ii) chitosan-coated PLGA (Chit.-PLGA), and (iii) Chit.-PLGA coated with different phospholipids (PL) (DPPC (100), DPPC:Chol (85:15), and DPPC:DOTAP (92:8). Differential stripping was performed, including complete mass balance. The samples were extracted for fluorescence quantification. An effect of the PL coating on follicular uptake was observed as DPPC (100) and DPPC:DOTAP (92:8) penetrated into HF to a higher extent than the other tested NP. The effect was observed both in the pig ear model as well as in human volunteers, although it was statistically significant only in the in vitro model. An excellent in vitro-in vivo correlation (IVIVC, r(2)=0.987) between both models was demonstrated, further supporting the suitability of the pig ear model as a surrogate for the in vivo situation in humans for quantifying NP uptake into HF. These findings may help to optimize NP for targeting the HF and to improve transdermal delivery.

Crystal suspensions of poorly soluble peptides for intra-articular application: a novel approach for biorelevant assessment of their in vitro release.

Crystal suspensions of 3 poorly soluble peptides (MSC1, 2 and 3), intended for intra-articular administration were prepared and in vitro release was tested by a modified USP IV apparatus, combined with a dialysis system. Half-lives of release profiles were ∼5 days for MSC1 and ∼0.5 days for MSC2 and MSC3, showing the potential to achieve sustained exposure from crystal suspensions after intra-articular administration. The in vitro release setup discriminated between (i) different formulations, (ii) different concentrations of API and (iii) different APIs. In addition it was shown that this method allows the modification of release conditions in order to gain more biorelevance for in vitro release testing in the field of intra-articular application: the influence of synovial fluid components hyaluronic acid and albumin was demonstrated, showing prolonged half-lives for suspensions containing 2.5% bovine serum albumin (5 days) and accelerated release rates for suspensions containing 1% sodium hyaluronate (2.5 days) in comparison to a suspension in phosphate buffered saline (4 days). Furthermore, it was demonstrated that release rates of a suspension containing an artificial synovial fluid were in accordance with suspensions containing bovine synovial fluid (t1/2∼4 days).

From the structure of the skin barrier and dermal formulations to in vitro transport models for skin absorption: skin research in the Netherlands and in Germany.

This review presents an overview of German and Dutch research institutions and their studies in the field of skin drug delivery and adjacent topics. In the Netherlands, the involved research groups are mainly localized in Leiden, whereas in Germany the skin research institutions are spread over the whole country. The scientific studies in the Netherlands focus on the in-depth analysis of human skin composition and its individual components as well as on the development and characterization of dermal drug delivery systems ranging from liquid crystalline systems and vesicles up to microneedles with an emphasis on examining the interactions of these drug delivery systems with the human skin in vitro and in vivo. In Germany, the individual areas of research span from in-depth investigations on various drug delivery systems intended for skin application and the development of novel in vitro models for skin absorption testing up to in vivo studies focusing on the biological performance of topically applied actives. Furthermore, sophisticated analytical techniques are applied for the elucidation of skin assembly and transport processes. In addition, experimentally derived data are correlated with advanced computational modelling. Even though the individual research topics in the Netherlands and Germany are quite diverse, the exchange of knowledge and interdisciplinary collaborations between the two neighbouring countries were and are still frequently made. In this context, the review aims at highlighting crosslinks between the different institutions and individual persons to complete the picture. For each institution, the principal investigators and their studies are presented and the upcoming young scientists are introduced as an outlook for the field. This review does not claim completeness, but is rather intended to give a general overview of Dutch and German research in the field of skin drug delivery and adjacent topics.

Finite dose skin mass balance including the lateral part: comparison between experiment, pharmacokinetic modeling and diffusion models.

This work investigates in vitro finite dose skin absorption of the model compounds flufenamic acid and caffeine experimentally and mathematically. The mass balance in different skin compartments (donor, stratum corneum (SC), deeper skin layers (DSL), lateral skin parts and acceptor) is analyzed as a function of time. For both substances high amounts were found in the lateral skin compartment after 6h of incubation, which emphasizes not to elide these parts in the modeling. Here, three different mathematical models were investigated and tested with the experimental data: a pharmacokinetic model (PK), a detailed microscopic two-dimensional diffusion model (MICRO) and a macroscopic homogenized diffusion model (MACRO). While the PK model was fitted to the experimental data, the MICRO and the MACRO models employed input parameters derived from infinite dose studies to predict the underlying diffusion process. All models could satisfyingly predict or describe the experimental data. The PK model and MACRO model also feature the lateral parts.

Pulmonary delivery and tissue distribution of aerosolized antisense 2'-O-Methyl RNA containing nanoplexes in the isolated perfused and ventilated rat lung.

Pulmonary delivery of drugs, particularly in the treatment of lung cancer, is an attractive strategy for future targeted therapy. In this context, inhalation of nanoplexes might offer a new mode for drug delivery in gene therapy. However, limited data are currently available demonstrating pulmonary delivery, cellular uptake as well as local tolerability in lung tissue. The aim of this study was to elucidate the pulmonary delivery, tissue distribution and local tolerability of aerosolized chitosan-coated poly(lactide-co-glycolide) based nanoplexes containing antisense 2'-O-Methyl RNA (OMR). Therefore, an aerosol of OMR-nanoplexes or OMR alone was administered intra-tracheally using the model of the isolated perfused and ventilated rat lung. Localization of OMR in rat lung tissue was examined by immunohistochemistry. Administration of the OMR-nanoplex formulation resulted in significantly higher cellular OMR uptake of the respiratory epithelium in contrast to the administration of OMR alone, indicating that drug administration via aerosolized nanoplexes is able to target lung tissue. No prominent changes in lung physiology parameters were observed following inhalation, suggesting good local tolerability of OMR-nanoplex formulation.