Composition and Charge Compensation in Chitosan/Gum Arabic Complex Coacervates in Dependence on pH and Salt Concentration.

In this study, complex coacervates of the biopolyelectrolytes chitosan and gum arabic were investigated with respect to their composition and charge compensation depending on the pH and salt concentration. Individual polyelectrolyte yields were deduced from thermogravimetric analysis and chitosan quantification via enzymatic hydrolysis/HPLC-ELSD. The polyelectrolyte mass ratio in the complex coacervate is found to remain approximately constant irrespective of the pH, despite the latter's effect on the polyelectrolyte charge ratio. Two regimes are identified, including either chitosan charges in excess (at pH < 6.0) or gum arabic charges in excess (at pH > 6.0). The amount of extrinsic charge compensation in the complex coacervates is discussed in detail. We show for the first time that the doping level, a quantity traditionally used to describe salt-induced changes of the charge compensation in polyelectrolyte complexes, is also suitable for the description of pH-induced extrinsic charge compensation in such systems.

Percutaneous Bioelectric Current Stimulation in the Treatment of Chronic Achilles Tendinopathy: Protocol for a Double-Blind, Placebo-Controlled Randomized Multicenter Trial.

BACKGROUND: The consensus for the optimal treatment strategy for chronic Achilles tendinopathy (AT) is still debated and treatment options are limited. This results in a significant medical need for more effective treatment options. OBJECTIVE: The aim of this study is to investigate the therapeutic effects of percutaneous bioelectric current stimulation (PBCS) on AT. METHODS: A multicenter, randomized, double-blind, placebo-controlled clinical trial will be conducted. A total of 72 participants with chronic (ie, >3 months) midpoint AT will be randomized and receive four PBCS sessions-either verum or placebo-over 3 weeks. Both groups will complete daily Achilles tendon loading exercises in addition to the intervention. Evaluation sessions will be completed at baseline and during the intervention (weeks 0-3). Self-reported outcome measures will be completed at follow-up at weeks 4, 12, 26, and 52. The primary outcomes are the Victorian Institute of Sports Assessment-Achilles questionnaire scores and statistical evaluation of intraindividual differences between baseline and 12-week evaluations after initial treatment of verum therapy compared to control. Secondary outcomes will assess Pain Disability Index scores; average pain, using the 11-point Numeric Rating Scale; return to sports; and use of emergency medication. RESULTS: The study began in May 2021. As of October 2022, we randomized 66 out of 72 participants. We anticipate completing recruitment by the end of 2022 and completing primary data analysis by March 2023. CONCLUSIONS: The study will evaluate the effects of PBCS on pain, physical function, and clinical outcomes. TRIAL REGISTRATION: German Clinical Trials Register DRKS00017293; https://tinyurl.com/mvz7s98k. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/40894.

Quantification of chitosan in aqueous solutions by enzymatic hydrolysis and oligomer analysis via HPLC-ELSD.

A new method for quantitative analysis of chitosan in aqueous solution is introduced, comprising an enzyme-driven cleavage to water-soluble chitooligosaccharides (COS), N-acetylation, separation via UHPLC and detection by use of an evaporative light scattering detector (ELSD). Chitosans with different fractions of acetylation (FA) and molecular weights (Mw) were hydrolyzed using a chitosanase/chitinase mixture. By subsequent N-acetylation with isotopically labelled acetic anhydride, COS mixtures with FA = 1 were obtained allowing for chromatographic separation solely based on their degree of polymerization (DP). ELSD data conversion into molar concentrations was realized using COS-specific external calibration curves, and mass spectrometry (MS) data informed about the chitosan's FA. The overall chitosan concentration was determined by simple addition of the COS concentrations multiplied by their DP. Validity of the method is shown for chitosan in presence of various co-solutes such as the protein BSA, the polysaccharide dextran and the monosaccharide glucosamine.

Pain localization in cluster headache patients: Onset, peak, and radiation.

OBJECTIVE AND AIM: To describe differences in pain locations for onset, peak, and radiation aspects of cluster headache (CH) attacks. METHODS AND MATERIALS: Data were collected for 23 months using a cross-sectional online survey composed of 117 questions on pain location, demographics, and clinical features. 5260 datapoints on 44 pain locations from 631 respondents were analyzed. RESULTS: During the onset and peak of attacks, pain is concentrated periorbitally. Pain locations outside the periorbital region were reported more frequently for radiation than for onset and peak of attacks. Dorsal (occipital, neck, shoulder) pain was reported more frequently in connection with onset and radiation than during peak: onset (13%) versus peak (6%), p < 0.001, and radiation (22%) versus peak (6%), p < 0.001. There was no significant difference in dorsal pain frequencies for onset (13%) vs. radiation (22%), p = 0.552. Furthermore, the frequency with which individual pain locations were reported differed significantly for onset, peak, and radiation in CH. CONCLUSIONS: Analysis of the pain location data shows specific frequencies and distributions of pain location for three aspects of CH attacks. The frequency with which individual pain points were reported differed significantly for onset, peak, and radiation. In general, dorsal pain points were reported more frequently for onset and radiation than for peak pain. Pain locations beyond the eye (extraorbital points) were more frequently reported in connection with radiating pain. Our findings could serve as a basis for future research, correlating CH pain patterns with the outcome of treatment approaches.

Direct synthesis of dilithium tetraphenylporphyrin: facile reaction of a free-base porphyrin with vapor-deposited lithium.

A solvent-free dilithium porphyrin was synthesized by direct reaction of free-base meso-tetraphenylporphyrin with elemental lithium in ultra-high vacuum. The reaction product dilithium tetraphenylporphyrin was studied by temperature-programmed desorption mass spectrometry (TPD-MS) and hard X-ray photoelectron spectroscopy (HAXPES). The solid-state reaction is thermodynamically favored, according to density functional theory (DFT) calculations.

Clinimetric properties and suitability of selected quality indicators for assessing antibiotic use in hospitalized adults: a multicentre point prevalence study in 24 hospitals in Germany.

OBJECTIVES: The capability to measure and monitor the quality of antibiotic prescribing is an important component of antibiotic stewardship (ABS) programmes. Several catalogues of consensus-based structure and process-of-care quality indicators (QIs) have been proposed, but only a few studies have tested and validated ABS QIs in practice tests. This multicentre study determined the clinimetric properties and suitability of a set of 33 process QIs for ABS that had earlier been developed and in part recommended in a German-Austrian hospital ABS practice guideline. METHODS: Two point prevalence surveys were conducted in a convenience sample of 24 acute care hospitals throughout Germany, and data of all screened adult inpatients with prescription of a systemic antibiotic at a given day (n=4310) were included in the study. For each QI, the following clinimetric properties were assessed: applicability, feasibility, performance, case mix stability and interobserver reliability. RESULTS: Eighteen QIs were considered sufficiently feasible, applicable and reliable, and had adequate room for improvement. The finally selected QIs primarily cover antibiotic therapy of common infections (bloodstream infection, pneumonia and urinary tract infection), while two of the QIs each address surgical prophylaxis and general aspects of antibiotic administration. CONCLUSIONS: Practice tests may be important to test the suitability of consensus process-of-care QIs in the field of hospital ABS. The 18 selected QIs considered suitable enough for hospital ABS in this study should be regarded as priority QIs useful for internal quality control and assurance. More research and additional practice tests may be needed to confirm their suitability for external quality assessment schemes.

Validation of adapted daily dose definitions for hospital antibacterial drug use evaluation: a multicentre study.

Background: The WHO/ATC (Anatomical Therapeutic Chemical) index DDD (WHO-DDD) is commonly used for drug consumption measurement. Discrepancies between WHO-DDD and actual prescribed daily doses (PDD) in hospitals have prompted alternative dose definitions adapted to doses recommended in hospital practice guidelines [recommended daily doses (RDD)]. Methods: In order to validate RDD we performed modified point prevalence surveys in 24 acute care hospitals and recorded 20620 PDD of antibiotics given to 4226 adult patients on the day of the survey and the 6 preceding days. We calculated RDD and WHO-DDD and compared them with PDD. Results: The rate of RDD corresponding to PDD was higher than the corresponding rate for WHO-DDD (pooled data, 55% versus 30%) and the differences were similar across the hospital sample, but varied according to drug/drug class, route of administration, indication and renal function. RDD underestimated actual consumption by 14% overall, while WHO-DDD overestimated total antibacterial consumption by 28% (pooled data; median values RDD -10% versus WHO-DDD +32%). The deviations of estimated from actual drug use volumes were largest for ß-lactams (RDD -11% versus WHO-DDD +49%), in particular for penicillins (-11% versus +64%), if WHO-DDD were used. Conclusions: Hospital antibiotic consumption surveillance systems using current WHO-DDD should address the uneven discrepancies between actual prescribing and consumption estimates according to drug class that may lead to misclassification in benchmark analyses. We recommend using validated RDD as a supplementary measure to the WHO-DDD for detailed analyses.