586 research outputs found
Nuclear magnetic resonance measurements reveal the origin of the Debye process in monohydroxy alcohols
Monohydroxy alcohols show a structural relaxation and at longer time scales a
Debye-type dielectric peak. From spin-lattice relaxation experiments using
different nuclear probes an intermediate, slower-than-structural dynamics is
identified for n-butanol. Based on these findings and on diffusion
measurements, a model of self-restructuring, transient chains is proposed. The
model is demonstrated to explain consistently the so far puzzling observations
made for this class of hydrogen-bonded glass forming liquids.Comment: 4 pages, 4 figure
Spatiotemporal visualization of the dynamics of absorbing layers in a two-stage atomizer
This paper describes an experimental apparatus for studying the dynamics of the variation of the spatial distribution of the absorbing layers in a two-stage atomizer. An optical system with a telecentric beam, using a diode laser as the radiation source, is proposed and analyzed. The spatiotemporal resolution and the contribution of refraction effects to the resulting absorption pattern are estimated. The dynamics of the evaporation and condensation processes are visualized in a two-stage atomizer of Cd atoms and NaCl molecules
A randomised, double-blind, placebo-controlled phase 3 study of lenabasum in diffuse cutaneous systemic sclerosis: RESOLVE-1 design and rationale
OBJECTIVES:
The multi-systemic, heterogenous nature of diffuse cutaneous systemic sclerosis (dcSSc) presents challenges in designing clinical studies that can demonstrate a treatment effect on overall disease burden. We describe the design of the first Phase 3 study in dcSSc patients where the American College of Rheumatology (ACR) Combined Response Index in diffuse cutaneous Systemic Sclerosis (CRISS) score was chosen prospectively as the primary outcome. The CRISS measures key clinical disease parameters and patient-reported outcomes (PROs).
METHODS:
RESOLVE-1 is a Phase 3, randomised, double-blind, placebo-controlled trial of dcSSc patients evaluating the efficacy and safety of lenabasum. Patients ≥18 years of age with dc-SSc and disease duration ≤6 years were eligible. Patients could continue stable background therapy for dcSSc, including stable immunosuppressive therapies. They were randomised to lenabasum 5 or 20 mg twice daily or placebo. The primary efficacy outcome was the mean change from baseline to 52 weeks in the ACR CRISS score.
RESULTS:
The study enrolled 365 patients over 1.5 years at 77 sites in 13 countries in North America, Europe, Israel, and Asia-Pacific, with the last patient first visit on May 1, 2019.
CONCLUSIONS:
RESOLVE-1 is the first Phase 3 interventional study to date in dcSSc to prospectively use the ACR CRISS as the primary efficacy outcome. Eligibility criteria allowed background therapy as might occur in clinical practice. This approach also facilitated timely patient enrolment. RESOLVE-1 provides a novel study design that may be used for future Phase 3 dcSSc studies to assess the holistic efficacy of therapy
Platform-to-platform sample transfer, distribution, dilution, and dosing via electrothermal vaporization and electrostatic deposition
A novel system for solid sample pretreatment, handling and dosing for analytical atomic spectrometry is described. A primary solid or liquid sample is vaporized in a graphite furnace and then condensed in a specially designed condensation zone. On the further transport path, the analyte aerosol can be diluted and distributed in pre-set ratios in the laboratory made flow control system. Applying a corona discharge, aerosol particulates are then quantitatively re-collected by means of intra-furnace electrostatic precipitation on the platform of another graphite furnace or by external precipitation on one or a set of platforms. This makes possible to produce a set of secondary platforms with equal analyte compositions from one individual primary sample. Such multitudes allow sequential multi-element determinations with single-element instrumentation or comparative measurements with different techniques. Furthermore, the described procedure allows external thermal sample pretreatment with preceding pyrolysis and additional vaporization, condensation, and re-precipitation that significantly reduces or removes the sample matrix. Owing to different losses, transport efficiencies of electrothermal vaporization (ETV) instrumentation depend on analyte element, matrix, vaporization temperature, ramp rate, and tube history. In order to reduce the losses and therewith such dependencies of the losses, new laboratory constructed ETV unit with analyte condensation in an axially focusing upstream convection zone has been constructed. Analytical performance of the new setup is compared with the performance of a commercial end-on flow-through ETV unit when analyzing both liquid dosed samples and certified solid reference materials. The new system shows much higher transport efficiencies that are, in addition, more uniform for elements of different volatility. The effects of chemical sample modifiers and elements supporting analyte condensation are studied. Most of the analytical measurements were carried out with a continuum source coherent forward scattering multi-element spectrometer. Comparative measurements were also carried out independently in the co-authors' laboratories with atomic absorption and inductively coupled plasma mass spectrometry techniques. © 2004 Elsevier B.V. All rights reserved
Systemic pharmacological treatment of digital ulcers in systemic sclerosis: a systematic literature review
Objective: To evaluate the evidence concerning systemic pharmacological treatments for SSc digital ulcers (DUs) to inform the development of evidence-based treatment guidelines. Methods: A systematic literature review of seven databases was performed to identify all original research studies of adult patients with SSc DUs. Randomized controlled trials (RCTs) and prospective longitudinal observational studies (OBSs) were eligible for inclusion. Data were extracted, applying the patient, intervention, comparison, outcome framework, and risk of bias (RoB) was assessed. Due to study heterogeneity, narrative summaries were used to present data. Results: Forty-seven studies that evaluated the treatment efficacy or safety of pharmacological therapies were identified among 4250 references. Data from 18 RCTs of 1927 patients and 29 OBSs of 661 patients, at various RoB (total 2588 patients) showed that i.v. iloprost, phosphodiesterase-5 inhibitors and atorvastatin are effective for the treatment of active DUs. Bosentan reduced the rate of future DUs in two RCTs (moderate RoB) and eight OBSs at low to high RoB. Two small studies (moderate RoB) indicate that Janus kinase inhibitors may be effective for the treatment of active DUs, otherwise there are no data to support the use of immunosuppression or anti-platelet agents in the management of DUs. Conclusion: There are several systemic treatments, across four medication classes, that are effective therapies for the management of SSc DUs. However, a lack of robust data means it is not possible to define the optimal treatment regimen for SSc DUs. The relatively low quality of evidence available has highlighted further areas of research need
Non-surgical local treatments of digital ulcers in systemic sclerosis: a systematic literature review
Introduction: Digital ulcers (DUs) are difficult to treat in patients with systemic sclerosis (SSc) and systemic (i.e., pharmacological) therapy is currently considered the 'standard of care'. Our aim was to examine the safety and efficacy of local, non-surgical treatment for SSc-DUs. Methods: A systematic literature review (SLR) of original research articles up to August, 29 2022 was performed according to the PICO framework. References were independently screened by two reviewers and risk of bias was assed using validated tools. Due to study heterogeneity narrative summaries are used to present data. Results: Among 899 retrieved references, 14 articles were included (2 randomised trials (RTs), and 12 observational (OBS) studies). The most frequently studied procedure (5 studies) was botulin A toxin (hand or single finger) injection with a reported healing rate (HR) of 71%-100%. Amniotic and hydrocolloid membranes were examined in one study each and associated with a good HR. Tadalafil 2% cream was studied in a single study with a reduction in the number of DUs. Vitamin E gel was associated with a reduction in ulcer healing time. Low-level light therapy, hydrodissection and corticosteroid injection, extracorporeal shock wave (ESW) and photobiomodulation were evaluated in a single study each and showed a positive trend. Dimethyl sulfoxide was associated with significant local toxicity. Conclusions: A range of non-surgical, local treatments for SSc-DUs have been explored and showed efficacy to some extent. We have identified methodological flaws that should be avoided in the design of future studies to explore locally-acting treatments for SSc-DUs
Surgical management of digital ulcers in systemic sclerosis: A systematic literature review
Background: There is a strong rationale to develop locally-acting surgical treatments for digital ulcers (DUs) in patients with systemic sclerosis (SSc). Our aim was to examine the safety and efficacy of local surgical management for SSc-DU. Methods: A systematic literature review was carried out until to August 2022 using 7 different databases. Original research studies concerning adult patients with SSc-DUs, and local surgical treatments were analysed using the PICO framework. We included randomized controlled trials, prospective/retrospective studies, and case series (minimum of 3 patients) References were independently screened by two reviewers including assessment of the risk of bias using validated tools. Results: Out of 899, 13eligible articles were included. Autologous fat (adipose tissue AT) grafting was the surgical modality most identified (7 studies, 1 randomized controlled double blinded trial and 6 prospective open-label single arm studies). The healing rate (HR) with autologous fat grafting (4 studies) was 66-100 %. Three studies reported autologous adipose-derived stromal vascular fraction grafting: HR of 32-60 %. Bone marrow derived cell transplantation in a single study showed 100 % healing rate over 4-24 weeks. Surgical sympathectomy was examined in 3 studies, prospective without comparator with a median healing rate of 81 %. Two surgical studies (of direct microsurgical revascularisation and microsurgical arteriolysis) showed 100 % healing of ulcers, with no complications. Conclusion: Several surgical approaches for SSc-DUs have demonstrated some degree of safety and effectiveness for DU healing. However, there are significant methodological issues. Future studies are warranted to rigorously investigate surgical interventions for SSc-DUs
Conservation of copy number profiles during engraftment and passaging of patient-derived cancer xenografts
Patient-derived xenografts (PDXs) are resected human tumors engrafted into mice for preclinical studies and therapeutic testing. It has been proposed that the mouse host affects tumor evolution during PDX engraftment and propagation, affecting the accuracy of PDX modeling of human cancer. Here, we exhaustively analyze copy number alterations (CNAs) in 1,451 PDX and matched patient tumor (PT) samples from 509 PDX models. CNA inferences based on DNA sequencing and microarray data displayed substantially higher resolution and dynamic range than gene expression-based inferences, and they also showed strong CNA conservation from PTs through late-passage PDXs. CNA recurrence analysis of 130 colorectal and breast PT/PDX-early/PDX-late trios confirmed high-resolution CNA retention. We observed no significant enrichment of cancer-related genes in PDX-specific CNAs across models. Moreover, CNA differences between patient and PDX tumors were comparable to variations in multiregion samples within patients. Our study demonstrates the lack of systematic copy number evolution driven by the PDX mouse host.</p
Immunochip analysis identifies multiple susceptibility loci for systemic sclerosis
In this study, 1,833 systemic sclerosis (SSc) cases and 3,466 controls were genotyped with the Immunochip array. Classical alleles, amino acid residues, and SNPs across the human leukocyte antigen (HLA) region were imputed and tested. These analyses resulted in a model composed of six polymorphic amino acid positions and seven SNPs that explained the observed significant associations in the region. In addition, a replication step comprising 4,017 SSc cases and 5,935 controls was carried out for several selected non-HLA variants, reaching a total of 5,850 cases and 9,401 controls of European ancestry. Following this strategy, we identified and validated three SSc risk loci, including DNASE1L3 at 3p14, the SCHIP1-IL12A locus at 3q25, and ATG5 at 6q21, as well as a suggested association of the TREH-DDX6 locus at 11q23. The associations of several previously reported SSc risk loci were validated and further refined, and the observed peak of association in PXK was related to DNASE1L3. Our study has increased the number of known genetic associations with SSc, provided further insight into the pleiotropic effects of shared autoimmune risk factors, and highlighted the power of dense mapping for detecting previously overlooked susceptibility loci
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