Image-guided Interstitial Brachytherapy in the Treatment of Primary and Recurrent Vulvovaginal Gynaecological Malignancies.

AIMS: To evaluate the use, outcomes and toxicities of high dose rate brachytherapy (HDRB) to the vulvovaginal region in previously irradiated and radiotherapy-naïve patients for primary or recurrent gynaecological malignancies. MATERIALS AND METHODS: From January 2010 to December 2020, 94 women with a median age of 64 years (range 31-88 years) were treated with interstitial HDRB for vulvovaginal disease. Treatment details, including cumulative radiotherapy doses, were recorded together with reported toxicity, using Common Terminology Criteria for Adverse Events (CTCAE) grading. Dosimetric parameters, including D90, V100 and V150 together with treatment response at 3 months, overall survival, relapse-free survival and long-term toxicity data, were collated from referring centres. RESULTS: The median follow-up was 78 months (range 2-301). Primary sites of disease included vagina (37), endometrium (29), vulva (16), ovary (7) and cervix (5). Eighty-six (91.5%) patients were treated with curative intent, eight (8.5%) were palliative treatments. Fifty patients received HDRB for recurrent disease, 39 patients for primary disease and five as part of adjuvant treatment. The anatomical site of disease treated with HDRB ranged from vagina (76), vulva (14) and peri-urethral sites (four). The 2- and 5-year local relapse-free survival rates were 76% and 72%, respectively; 15 patients experienced local failure only, whereas six patients had local and nodal/distant failure. The median time to local recurrence was 8 months (range 2-88 months). The 2- and 5-year overall survival rates for all patients were 67% and 47%, respectively; the median overall survival was 59 months. Seventy-nine (84%) patients had a complete response measured with imaging at 3 months. Grade 3 toxicity was reported in 14 patients (14.8%). CONCLUSION: This retrospective series suggests the use of interstitial brachytherapy for vulvovaginal gynaecological malignancy to be an effective and safe treatment option. Good local control was achieved with a tolerable toxicity profile; it is a valuable treatment modality.

Correlative Atomic Force Microscopy and Raman Spectroscopy in Acid Erosion of Dentin.

Physical properties and chemical composition are fundamentally defining and interconnected surface characteristics. However, few techniques are able to capture both in a correlative fashion at the same sample location and orientation. This is especially important for complex materials such as dentin, which is an inner tooth structure and is a heterogeneous, composite inorganic-organic material with open channels (tubules) that extend toward the tooth pulp. Here, a combined microscope system consisting of an atomic force microscope and a confocal Raman spectrometer was used to study the correlative physical and chemical properties of human dentin. The local hardness of dentin was highly correlated with the Raman signal ratio of inorganic to organic material, and this was enhanced in the peritubular regions of dentin. When the samples were etched with citric acid, Young's modulus, hardness, and inorganic-to-organic material ratio decreased significantly, collagen fibrils on the surface were exposed, the peritubular regions were removed, and the tubule diameters increased. Thus, the combined atomic force microscopy (AFM)-Raman approach allows for comprehensive and correlative physical-chemical analysis of material surfaces and will be invaluable for evaluating oral therapeutic strategies.

Real-World Treatment Patterns, Resource Use and Costs in Adult Patients With Atopic Dermatitis Receiving Systemic Treatment: Derma-Atopic Study in Spain / Características de los pacientes, patrones de tratamiento, uso de recursos y costes en adultos con dermatitis atópica moderada-grave en la práctica habitual en España: Estudio Derma-Atopic

Background Moderate–severe atopic dermatitis (AD) has a significant impact on patients’ lives, with many requiring systemic treatment to manage symptoms (e.g., pruritus). Several drugs are used off-label to treat AD. This study describes sociodemographic/clinical characteristics, treatment patterns, health resource use (HRU) and costs in adults with AD who initiated systemic treatment or phototherapy in routine practice. Methods This retrospective observational study of electronic medical records in the BIG-PAC database identified adults with prior diagnosis of AD (ICD-9: 691.8 or 692.9) starting oral corticosteroids, immunosuppressants, biologics or phototherapy between 01/01/2012 and 31/12/2016. Patients were followed for 3 years from treatment initiation, up to 31/12/2019. Data on patient characteristics, treatment patterns, HRU and costs were analyzed descriptively. Results Patients (N = 1995) had a mean age of 60 years, 64% were female, with a mean time of 23 years since diagnosis (84% were ≥18 years at AD onset). Main comorbidities were anxiety (38%), arterial hypertension (36%) and dyslipidemia (35%). Most patients used oral corticosteroids as first systemic (84%; median duration 29 days) and immunosuppressants in 13% of patients (median duration 117 days, 5% cyclosporine and 4% methotrexate). Half of patients required a second line systemic and 12% a third line. The use of immunosuppressants and biologics increased with treatment lines. About 13% of patients received systemic treatments continuously over the 3-year follow-up. The average 3-year per patient cost was 3835 euros, with an average annual cost of 1278 euros. Conclusions Results suggest a high comorbidity and economic burden in this real-world adult population with AD, and the need for systemic treatments indicated for use in AD (AU)

Antecedentes La dermatitis atópica (DA) moderada-grave tiene un impacto significativo en la vida de los pacientes, muchos de los cuales requieren tratamiento sistémico para controlar los síntomas (p. ej., prurito). Algunos tratamientos son usados fuera de indicación. Este estudio describió características sociodemográficas y clínicas, patrones de tratamiento, uso de recursos sanitarios (URS) y costes asociados en adultos con DA que iniciaron tratamiento sistémico o fototerapia en la práctica habitual. Métodos Este estudio observacional retrospectivo de historias clínicas electrónicas en la base de datos BIG-PAC identificó adultos con diagnóstico previo de DA (CIE-9: 691.8 o 692.9) que comenzaron con corticosteroides orales, inmunosupresores, biológicos o fototerapia entre el 01/01/2012 y el 31/12/2016. Se siguió a los pacientes durante 3 años desde el inicio del tratamiento, hasta 31/12/2019. Los datos sobre las características clínicas de los pacientes, patrones de tratamiento, URS y costes se analizaron de forma descriptiva. Resultados Los pacientes (N = 1995) tenían una edad media de 60 años, el 64% eran mujeres, con una media de 23 años desde el diagnóstico (84% tenían ≥ 18 años al inicio de la DA). Las principales comorbilidades fueron ansiedad (38%), hipertensión arterial (36%) y dislipidemia (35%). La mayoría de los pacientes utilizaron corticosteroides orales como primer tratamiento sistémico (84%; duración media 29 días) e inmunosupresores en el 13% de los pacientes (duración media 117 días, ciclosporina en el 5% y metotrexato en el 4%). La mitad de los pacientes requirieron una segunda línea de tratamiento sistémico y el 12% una tercera. El uso de inmunosupresores y biológicos aumentó simultáneamente con las líneas de tratamiento. Aproximadamente el 13% de los pacientes recibieron tratamientos sistémicos de forma continua durante los 3 años de seguimiento. El coste medio por paciente a 3 años fue de 3.835 euros, con un coste medio anual de 1.278 euros (AU)

[Artículo traducido] Características de los pacientes, patrones de tratamiento, uso de recursos y costes en adultos con dermatitis atópica moderada-grave en la práctica habitual en España: Estudio Derma-Atopic / Real-World Treatment Patterns, Resource Use and Costs in Adult Patients With Atopic Dermatitis Receiving Systemic Treatment: Derma-Atopic Study in Spain

Antecedentes La dermatitis atópica (DA) moderada-grave tiene un impacto significativo en la vida de los pacientes, muchos de los cuales requieren tratamiento sistémico para controlar los síntomas (p. ej., prurito). Algunos tratamientos son usados fuera de indicación. Este estudio describió características sociodemográficas y clínicas, patrones de tratamiento, uso de recursos sanitarios (URS) y costes asociados en adultos con DA que iniciaron tratamiento sistémico o fototerapia en la práctica habitual. Métodos Este estudio observacional retrospectivo de historias clínicas electrónicas en la base de datos BIG-PAC identificó adultos con diagnóstico previo de DA (CIE-9: 691.8 o 692.9) que comenzaron con corticosteroides orales, inmunosupresores, biológicos o fototerapia entre el 01/01/2012 y el 31/12/2016. Se siguió a los pacientes durante 3 años desde el inicio del tratamiento, hasta 31/12/2019. Los datos sobre las características clínicas de los pacientes, patrones de tratamiento, URS y costes se analizaron de forma descriptiva. Resultados Los pacientes (N = 1995) tenían una edad media de 60 años, el 64% eran mujeres, con una media de 23 años desde el diagnóstico (84% tenían ≥ 18 años al inicio de la DA). Las principales comorbilidades fueron ansiedad (38%), hipertensión arterial (36%) y dislipidemia (35%). La mayoría de los pacientes utilizaron corticosteroides orales como primer tratamiento sistémico (84%; duración media 29 días) e inmunosupresores en el 13% de los pacientes (duración media 117 días, ciclosporina en el 5% y metotrexato en el 4%). La mitad de los pacientes requirieron una segunda línea de tratamiento sistémico y el 12% una tercera. El uso de inmunosupresores y biológicos aumentó simultáneamente con las líneas de tratamiento. Aproximadamente el 13% de los pacientes recibieron tratamientos sistémicos de forma continua durante los 3 años de seguimiento. El coste medio por paciente a 3 años fue de 3.835 euros, con un coste medio anual de 1.278 euros (AU)

Background Moderate–severe atopic dermatitis (AD) has a significant impact on patients’ lives, with many requiring systemic treatment to manage symptoms (e.g., pruritus). Several drugs are used off-label to treat AD. This study describes sociodemographic/clinical characteristics, treatment patterns, health resource use (HRU) and costs in adults with AD who initiated systemic treatment or phototherapy in routine practice. Methods This retrospective observational study of electronic medical records in the BIG-PAC database identified adults with prior diagnosis of AD (ICD-9: 691.8 or 692.9) starting oral corticosteroids, immunosuppressants, biologics or phototherapy between 01/01/2012 and 31/12/2016. Patients were followed for 3 years from treatment initiation, up to 31/12/2019. Data on patient characteristics, treatment patterns, HRU and costs were analyzed descriptively. Results Patients (N = 1995) had a mean age of 60 years, 64% were female, with a mean time of 23 years since diagnosis (84% were ≥18 years at AD onset). Main comorbidities were anxiety (38%), arterial hypertension (36%) and dyslipidemia (35%). Most patients used oral corticosteroids as first systemic (84%; median duration 29 days) and immunosuppressants in 13% of patients (median duration 117 days, 5% cyclosporine and 4% methotrexate). Half of patients required a second line systemic and 12% a third line. The use of immunosuppressants and biologics increased with treatment lines. About 13% of patients received systemic treatments continuously over the 3-year follow-up. The average 3-year per patient cost was 3835 euros, with an average annual cost of 1278 euros. Conclusions Results suggest a high comorbidity and economic burden in this real-world adult population with AD, and the need for systemic treatments indicated for use in AD (AU)

Real-World Treatment Patterns, Resource Use and Costs in Adult Patients With Atopic Dermatitis Receiving Systemic Treatment: Derma-Atopic Study in Spain.

BACKGROUND: Moderate-severe atopic dermatitis (AD) has a significant impact on patients' lives, with many requiring systemic treatment to manage symptoms (e.g., pruritus). Several drugs are used off-label to treat AD. This study describes sociodemographic/clinical characteristics, treatment patterns, health resource use (HRU) and costs in adults with AD who initiated systemic treatment or phototherapy in routine practice. METHODS: This retrospective observational study of electronic medical records in the BIG-PAC database identified adults with prior diagnosis of AD (ICD-9: 691.8 or 692.9) starting oral corticosteroids, immunosuppressants, biologics or phototherapy between 01/01/2012 and 31/12/2016. Patients were followed for 3 years from treatment initiation, up to 31/12/2019. Data on patient characteristics, treatment patterns, HRU and costs were analyzed descriptively. RESULTS: Patients (N=1995) had a mean age of 60 years, 64% were female, with a mean time of 23 years since diagnosis (84% were ≥18 years at AD onset). Main comorbidities were anxiety (38%), arterial hypertension (36%) and dyslipidemia (35%). Most patients used oral corticosteroids as first systemic (84%; median duration 29 days) and immunosuppressants in 13% of patients (median duration 117 days, 5% cyclosporine and 4% methotrexate). Half of patients required a second line systemic and 12% a third line. The use of immunosuppressants and biologics increased with treatment lines. About 13% of patients received systemic treatments continuously over the 3-year follow-up. The average 3-year per patient cost was 3835 euros, with an average annual cost of 1278 euros. CONCLUSIONS: Results suggest a high comorbidity and economic burden in this real-world adult population with AD, and the need for systemic treatments indicated for use in AD.

Real-World Treatment Patterns, Resource Use and Costs in Adult Patients With Atopic Dermatitis Receiving Systemic Treatment: Derma-Atopic Study in Spain. / [Artículo traducido] Características de los pacientes, patrones de tratamiento, uso de recursos y costes en adultos con dermatitis atópica moderada-grave en la práctica habitual en España: Estudio Derma-Atopic.

BACKGROUND: Moderate-severe atopic dermatitis (AD) has a significant impact on patients' lives, with many requiring systemic treatment to manage symptoms (e.g., pruritus). Several drugs are used off-label to treat AD. This study describes sociodemographic/clinical characteristics, treatment patterns, health resource use (HRU) and costs in adults with AD who initiated systemic treatment or phototherapy in routine practice. METHODS: This retrospective observational study of electronic medical records in the BIG-PAC database identified adults with prior diagnosis of AD (ICD-9: 691.8 or 692.9) starting oral corticosteroids, immunosuppressants, biologics or phototherapy between 01/01/2012 and 31/12/2016. Patients were followed for 3 years from treatment initiation, up to 31/12/2019. Data on patient characteristics, treatment patterns, HRU and costs were analyzed descriptively. RESULTS: Patients (N = 1995) had a mean age of 60 years, 64% were female, with a mean time of 23 years since diagnosis (84% were ≥18 years at AD onset). Main comorbidities were anxiety (38%), arterial hypertension (36%) and dyslipidemia (35%). Most patients used oral corticosteroids as first systemic (84%; median duration 29 days) and immunosuppressants in 13% of patients (median duration 117 days, 5% cyclosporine and 4% methotrexate). Half of patients required a second line systemic and 12% a third line. The use of immunosuppressants and biologics increased with treatment lines. About 13% of patients received systemic treatments continuously over the 3-year follow-up. The average 3-year per patient cost was 3835 euros, with an average annual cost of 1278 euros. CONCLUSIONS: Results suggest a high comorbidity and economic burden in this real-world adult population with AD, and the need for systemic treatments indicated for use in AD.

Structure and Function of a Dehydrating Condensation Domain in Nonribosomal Peptide Biosynthesis.

Dehydroamino acids are important structural motifs and biosynthetic intermediates for natural products. Many bioactive natural products of nonribosomal origin contain dehydroamino acids; however, the biosynthesis of dehydroamino acids in most nonribosomal peptides is not well understood. Here, we provide biochemical and bioinformatic evidence in support of the role of a unique class of condensation domains in dehydration (CmodAA). We also obtain the crystal structure of a CmodAA domain, which is part of the nonribosomal peptide synthetase AmbE in the biosynthesis of the antibiotic methoxyvinylglycine. Biochemical analysis reveals that AmbE-CmodAA modifies a peptide substrate that is attached to the donor carrier protein. Mutational studies of AmbE-CmodAA identify several key residues for activity, including four residues that are mostly conserved in the CmodAA subfamily. Alanine mutation of these conserved residues either significantly increases or decreases AmbE activity. AmbE exhibits a dimeric conformation, which is uncommon and could enable transfer of an intermediate between different protomers. Our discovery highlights a central dehydrating function for CmodAA domains that unifies dehydroamino acid biosynthesis in diverse nonribosomal peptide pathways. Our work also begins to shed light on the mechanism of CmodAA domains. Understanding CmodAA domain function may facilitate identification of new natural products that contain dehydroamino acids and enable engineering of dehydroamino acids into nonribosomal peptides.

Brain Abnormalities in Patients with Germline Variants in H3F3: Novel Imaging Findings and Neurologic Symptoms Beyond Somatic Variants and Brain Tumors.

BACKGROUND AND PURPOSE: Pathogenic somatic variants affecting the genes Histone 3 Family 3A and 3B (H3F3) are extensively linked to the process of oncogenesis, in particular related to central nervous system tumors in children. Recently, H3F3 germline missense variants were described as the cause of a novel pediatric neurodevelopmental disorder. We aimed to investigate patterns of brain MR imaging of individuals carrying H3F3 germline variants. MATERIALS AND METHODS: In this retrospective study, we included individuals with proved H3F3 causative genetic variants and available brain MR imaging scans. Clinical and demographic data were retrieved from available medical records. Molecular genetic testing results were classified using the American College of Medical Genetics criteria for variant curation. Brain MR imaging abnormalities were analyzed according to their location, signal intensity, and associated clinical symptoms. Numeric variables were described according to their distribution, with median and interquartile range. RESULTS: Eighteen individuals (10 males, 56%) with H3F3 germline variants were included. Thirteen of 18 individuals (72%) presented with a small posterior fossa. Six individuals (33%) presented with reduced size and an internal rotational appearance of the heads of the caudate nuclei along with an enlarged and squared appearance of the frontal horns of the lateral ventricles. Five individuals (28%) presented with dysgenesis of the splenium of the corpus callosum. Cortical developmental abnormalities were noted in 8 individuals (44%), with dysgyria and hypoplastic temporal poles being the most frequent presentation. CONCLUSIONS: Imaging phenotypes in germline H3F3-affected individuals are related to brain features, including a small posterior fossa as well as dysgenesis of the corpus callosum, cortical developmental abnormalities, and deformity of lateral ventricles.

The utility of a standardised breath sampler in school age children within a real-world prospective study.

Clinical assessment of children with asthma is problematic, and non-invasive biomarkers are needed urgently. Monitoring exhaled volatile organic compounds (VOCs) is an attractive alternative to invasive tests (blood and sputum) and may be used as frequently as required. Standardised reproducible breath-sampling is essential for exhaled-VOC analysis, and although the ReCIVA (Owlstone Medical Limited) breath-sampler was designed to satisfy this requirement, paediatric use was not in the original design brief. The efficacy of the ReCIVA at sampling breath from children has been studied, and 90 breath-samples from 64 children (5-15 years) with, and without asthma (controls), were collected with two different ReCIVA units. Seventy samples (77.8%) contained the specified 1 l of sampled-breath. Median sampling times were longer in children with acute asthma (770.2 s, range: 532.2-900.1 s) compared to stable asthma (690.6 s, range: 477.5-900.1 s;p= 0.01). The ReCIVA successfully detected operational faults, in 21 samples. A leak, caused by a poor fit of the face mask seal was the most common (15); the others were USB communication-faults (5); and, a single instance of a file-creation error. Paediatric breath-profiles were reliably monitored, however synchronisation of sampling to breathing-phases was sometimes lost, causing some breaths not to be sampled, and some to be sampled continuously. This occurred in 60 (66.7%) of the samples and was a source of variability. Importantly, multi-variate modelling of untargeted VOC analysis indicated the absence of significant batch effects for eight operational variables. The ReCIVA appears suitable for paediatric breath-sampling. Post-processing of breath-sample meta-data is recommended to assess the quality of sample-acquisition. Further, future studies should explore the effect of pump-synchronisation faults on recovered VOC profiles, and mask sizes to fit all ages will reduce the potential for leaks and importantly, provide higher levels of comfort to children with asthma.

Biosynthesis of fluopsin C, a copper-containing antibiotic from Pseudomonas aeruginosa.

Metal-binding natural products contribute to metal acquisition and bacterial virulence, but their roles in metal stress response are underexplored. We show that a five-enzyme pathway in Pseudomonas aeruginosa synthesizes a small-molecule copper complex, fluopsin C, in response to elevated copper concentrations. Fluopsin C is a broad-spectrum antibiotic that contains a copper ion chelated by two minimal thiohydroxamates. Biosynthesis of the thiohydroxamate begins with cysteine and requires two lyases, two iron-dependent enzymes, and a methyltransferase. The iron-dependent enzymes remove the carboxyl group and the α carbon from cysteine through decarboxylation, N-hydroxylation, and methylene excision. Conservation of the pathway in P. aeruginosa and other bacteria suggests a common role for fluopsin C in the copper stress response, which involves fusing copper into an antibiotic against other microbes.

Type IV Pili-Independent Photocurrent Production by the Cyanobacterium Synechocystis sp. PCC 6803.

Biophotovoltaic devices utilize photosynthetic organisms such as the model cyanobacterium Synechocystis sp. PCC 6803 (Synechocystis) to generate current for power or hydrogen production from light. These devices have been improved by both architecture engineering and genetic engineering of the phototrophic organism. However, genetic approaches are limited by lack of understanding of cellular mechanisms of electron transfer from internal metabolism to the cell exterior. Type IV pili have been implicated in extracellular electron transfer (EET) in some species of heterotrophic bacteria. Furthermore, conductive cell surface filaments have been reported for cyanobacteria, including Synechocystis. However, it remains unclear whether these filaments are type IV pili and whether they are involved in EET. Herein, a mediatorless electrochemical setup is used to compare the electrogenic output of wild-type Synechocystis to that of a ΔpilD mutant that cannot produce type IV pili. No differences in photocurrent, i.e., current in response to illumination, are detectable. Furthermore, measurements of individual pili using conductive atomic force microscopy indicate these structures are not conductive. These results suggest that pili are not required for EET by Synechocystis, supporting a role for shuttling of electrons via soluble redox mediators or direct interactions between the cell surface and extracellular substrates.

Cell response to substrate rigidity is regulated by active and passive cytoskeletal stress.

Morphogenesis, tumor formation, and wound healing are regulated by tissue rigidity. Focal adhesion behavior is locally regulated by stiffness; however, how cells globally adapt, detect, and respond to rigidity remains unknown. Here, we studied the interplay between the rheological properties of the cytoskeleton and matrix rigidity. We seeded fibroblasts onto flexible microfabricated pillar arrays with varying stiffness and simultaneously measured the cytoskeleton organization, traction forces, and cell-rigidity responses at both the adhesion and cell scale. Cells adopted a rigidity-dependent phenotype whereby the actin cytoskeleton polarized on stiff substrates but not on soft. We further showed a crucial role of active and passive cross-linkers in rigidity-sensing responses. By reducing myosin II activity or knocking down α-actinin, we found that both promoted cell polarization on soft substrates, whereas α-actinin overexpression prevented polarization on stiff substrates. Atomic force microscopy indentation experiments showed that this polarization response correlated with cell stiffness, whereby cell stiffness decreased when active or passive cross-linking was reduced and softer cells polarized on softer matrices. Theoretical modeling of the actin network as an active gel suggests that adaptation to matrix rigidity is controlled by internal mechanical properties of the cytoskeleton and puts forward a universal scaling between nematic order of the actin cytoskeleton and the substrate-to-cell elastic modulus ratio. Altogether, our study demonstrates the implication of cell-scale mechanosensing through the internal stress within the actomyosin cytoskeleton and its coupling with local rigidity sensing at focal adhesions in the regulation of cell shape changes and polarity.

Broadband, millimeter-wave antireflection coatings for large-format, cryogenic aluminum oxide optics.

We present two prescriptions for broadband ($ {\sim} 77 - 252\;{\rm GHz} $), millimeter-wave antireflection coatings for cryogenic, sintered polycrystalline aluminum oxide optics: one for large-format (700 mm diameter) planar and plano-convex elements, the other for densely packed arrays of quasi-optical elements-in our case, 5 mm diameter half-spheres (called "lenslets"). The coatings comprise three layers of commercially available, polytetrafluoroethylene-based, dielectric sheet material. The lenslet coating is molded to fit the 150 mm diameter arrays directly, while the large-diameter lenses are coated using a tiled approach. We review the fabrication processes for both prescriptions, then discuss laboratory measurements of their transmittance and reflectance. In addition, we present the inferred refractive indices and loss tangents for the coating materials and the aluminum oxide substrate. We find that at 150 GHz and 300 K the large-format coating sample achieves $ (97 \pm 2)\% $ transmittance, and the lenslet coating sample achieves $ (94 \pm 3)\% $ transmittance.

A subtle relationship between substrate stiffness and collective migration of cell clusters.

The physical cues from the extracellular environment mediates cell signaling spatially and temporally. Cells respond to physical cues from their environment in a non-monotonic fashion. Despite our understanding of the role of substrate rigidity on single cell migration, how cells respond collectively to increasing extracellular matrix stiffness is not well established. Here we patterned multicellular epithelial Madin-Darby canine kidney (MDCK) islands on polyacrylamide gels of varying stiffness and studied their expansion. Our findings show that the MDCK islands expanded faster with increasing stiffness only up to an optimum stiffness, over which the expansion plateaued. We then focused on the expansion of the front of the assemblies and the formation of leader cells. We observed cell front destabilization only above substrate stiffness of a few kPa. The extension of multicellular finger-like structures at the edges of the colonies for intermediate and high stiffnesses from 6 to 60 kPa responded to higher substrate stiffness by increasing focal adhesion areas and actin cable assembly. Additionally, the number of leader cells at the finger-like protrusions increased with stiffness in correlation with an increase of the area of these multicellular protrusions. Consequently, the force profile along the epithelial fingers in the parallel and transverse directions of migration showed an unexpected relationship leading to a global force decrease with the increase of stiffness. Taken together, our findings show that epithelial cell colonies respond to substrate stiffness but in a non-trivial manner that may be of importance to understand morphogenesis and collective cell invasion during tumour progression.

Exceedingly Small Gadolinium Oxide Nanoparticles with Remarkable Relaxivities for Magnetic Resonance Imaging of Tumors.

Gd chelates have occupied most of the market of magnetic resonance imaging (MRI) contrast agents for decades. However, there have been some problems (nephrotoxicity, non-specificity, and low r1 ) that limit their applications. Herein, a wet-chemical method is proposed for facile synthesis of poly(acrylic acid) (PAA) stabilized exceedingly small gadolinium oxide nanoparticles (ES-GON-PAA) with an excellent water dispersibility and a size smaller than 2.0 nm, which is a powerful T1 -weighted MRI contrast agent for diagnosis of diseases due to its remarkable relaxivities (r1 = 70.2 ± 1.8 mM-1 s-1 , and r2 /r1 = 1.02 ± 0.03, at 1.5 T). The r1 is much higher and the r2 /r1 is lower than that of the commercial Gd chelates and reported gadolinium oxide nanoparticles (GONs). Further ES-GON-PAA is developed with conjugation of RGD2 (RGD dimer) (i.e., ES-GON-PAA@RGD2) for T1 -weighted MRI of tumors that overexpress RGD receptors (i.e., integrin αv ß3 ). The maximum signal enhancement (ΔSNR) for T1 -weighted MRI of tumors reaches up to 372 ± 56% at 2 h post-injection of ES-GON-PAA@RGD2, which is much higher than commercial Gd-chelates (<80%). Due to the high biocompatibility and high tumor accumulation, ES-GON-PAA@RGD2 with remarkable relaxivities is a promising and powerful T1 -weighted MRI contrast agent.

Reciprocal regulation of actomyosin organization and contractility in nonmuscle cells by tropomyosins and alpha-actinins.

Contractile arrays of actin and myosin II filaments drive many essential processes in nonmuscle cells, including migration and adhesion. Sequential organization of actin and myosin along one dimension is followed by expansion into a two-dimensional network of parallel actomyosin fibers, in which myosin filaments are aligned to form stacks. The process of stack formation has been studied in detail. However, factors that oppose myosin stack formation have not yet been described. Here, we show that tropomyosins act as negative regulators of myosin stack formation. Knockdown of any or all tropomyosin isoforms in rat embryonic fibroblasts resulted in longer and more numerous myosin stacks and a highly ordered actomyosin organization. The molecular basis for this, we found, is the competition between tropomyosin and alpha-actinin for binding actin. Surprisingly, excessive order in the actomyosin network resulted in smaller focal adhesions, lower tension within the network, and smaller traction forces. Conversely, disordered actomyosin bundles induced by alpha-actinin knockdown led to higher than normal tension and traction forces. Thus, tropomyosin acts as a check on alpha-actinin to achieve intermediate levels of myosin stacks matching the force requirements of the cell.

Cell shape and substrate stiffness drive actin-based cell polarity.

A general trait of living cells is their ability to exert contractile stresses on their surroundings and thus respond to substrate rigidity. At the cellular scale, this response affects cell shape, polarity, and ultimately migration. The regulation of cell shape together with rigidity sensing remains largely unknown. In this article we show that both substrate rigidity and cell shape contribute to drive actin organization and cell polarity. Increasing substrate rigidity affects bulk properties of the actin cytoskeleton by favoring long-lived actin stress fibers with increased nematic interactions, whereas cell shape imposes a local alignment of actin fibers at the cell periphery.

Quantitative mechanical analysis of indentations on layered, soft elastic materials.

Atomic force microscopy (AFM) is becoming an increasingly popular method for studying cell mechanics, however the existing analysis tools for determining the elastic modulus from indentation experiments are unable to quantitatively account for mechanical heterogeneity commonly found in biological samples. In this work, we numerically calculated force-indentation curves onto two-layered elastic materials using an analytic model. We found that the effect of the underlying substrate can be quantitatively predicted by the mismatch in elastic moduli and the homogeneous-case contact radius relative to the layer height for all tested probe geometries. The effect is analogous to one-dimensional Hookean springs in series and was phenomenologically modeled to obtain an approximate closed-form equation for the indentation force onto a two-layered elastic material which is accurate for up to two orders of magnitude mismatch in Young's modulus when the contact radius is less than the layer height. We performed finite element analysis simulations to verify the model and AFM microindentation experiments and macroindentation experiments to demonstrate its ability to deconvolute the Young's modulus of each layer. The model can be broadly used to quantify and serve as a guideline for designing and interpreting indentation experiments into mechanically heterogeneous samples.

The feasibility of using the EQ-5D-3L with adults with mild to moderate learning disabilities within a randomized control trial: a qualitative evaluation.

BACKGROUND: In trials incorporating a health economic evaluation component, reliable validated measures for health-related quality of life (HRQOL) are essential. The EQ-5D is the preferred measure for cost-effectiveness analysis in UK trials. This paper presents a qualitative evaluation of the use of the EQ-5D-3L in a feasibility randomised control trial with participants who had a mild- to  moderate learning disability and type 2 diabetes. METHODS: Researchers administered the EQ-5D-3L to 82 participants at baseline and 77 at follow-up. After each interview, researchers rated the ease of administering the EQ-5D-3L and made free-text entries on the administration experience. For a subset of 16 interviews, researchers audio-recorded more detailed journal entries. Ease of administration data were analysed using descriptive statistics. Free-text responses were subject to a basic content analysis. The EQ-5D-3L-related journal entries were transcribed, coded and analysed thematically. RESULTS: Over half of participants were perceived to experience difficulty answering some or all of the items in the EQ-5D-3L (60% at baseline; 54% at follow-up). Analysis of the free-text entries and audio journals identified four themes that question the use of the EQ-5D-3L in this population. The first theme is related to observations of participant intellectual ability and difficulties, for example, in understanding the wording of the measure. Theme 2 is related to the normalisation of adjustments for impairments, which rendered the measure less sensitive in this population. Theme 3 is related to researcher adaptation and non-standard administration. An overarching fourth theme was identified in that people with learning disabilities were viewed as 'unreliable witnesses' by both researchers and supporters. CONCLUSIONS: It is recommended that the EQ-5D-3L should not be used in isolation to assess health-related quality of life outcomes in trials research in adults with a learning disability. Further research is required to develop and evaluate a version of the EQ-5D appropriate for this population in trials research. It is unrealistic to expect that adjustments to the wording alone will deliver an appropriate measure: supporter or researcher involvement will almost always be required. This requirement needs to be factored into the development and administration guidelines of any new version of the EQ-5D for adults with a learning disability. TRIAL REGISTRATION: Current Controlled Trials ISRCTN41897033 [registered 21 January 2013].

A comparison of methods to assess cell mechanical properties.

The mechanical properties of cells influence their cellular and subcellular functions, including cell adhesion, migration, polarization, and differentiation, as well as organelle organization and trafficking inside the cytoplasm. Yet reported values of cell stiffness and viscosity vary substantially, which suggests differences in how the results of different methods are obtained or analyzed by different groups. To address this issue and illustrate the complementarity of certain approaches, here we present, analyze, and critically compare measurements obtained by means of some of the most widely used methods for cell mechanics: atomic force microscopy, magnetic twisting cytometry, particle-tracking microrheology, parallel-plate rheometry, cell monolayer rheology, and optical stretching. These measurements highlight how elastic and viscous moduli of MCF-7 breast cancer cells can vary 1,000-fold and 100-fold, respectively. We discuss the sources of these variations, including the level of applied mechanical stress, the rate of deformation, the geometry of the probe, the location probed in the cell, and the extracellular microenvironment.