Preparation and optimization of agarose or polyacrylamide/amino acid-based double network hydrogels for photocontrolled drug release

The high water content and biocompatibility of amino-acid-based supramolecular hydrogels have generated growing interest in drug delivery research. Nevertheless, the existing dominant approach of constructing such hydrogels, the exploitation of a single amino acid type, typically comes with several drawbacks such as weak mechanical properties and long gelation times, hindering their applications. Here, we design a near-infrared (NIR) light-responsive double network (DN) structure, containing amino acids and different synthetic or natural polymers, i.e., polyacrylamide, poly(N-isopropylacrylamide), agarose, or low-gelling agarose. The hydrogels displayed high mechanical strength and high drug-loading capacity. Adjusting the ratio of Fmoc-Tyr-OH/Fmoc-Tyr(Bzl)-OH or Fmoc-Phe-OH/Fmoc-Tyr(Bzl)-OH, we could drastically shorten the gelation time of the DN hydrogels at room and body temperatures. Moreover, introducing photothermal agents (graphene oxide, carbon nanotubes, molybdenum disulfide nanosheets, or indocyanine green), we equipped the hydrogels with NIR responsivity. We demonstrated the light-triggered release of the drug baclofen, which is used in severe spasticity treatment. Rheology and stability tests confirmed the positive impact of the polymers on the mechanical strength of the hydrogels, while maintaining good stability under physiological conditions. Overall, our study contributed a novel hydrogel formulation with high mechanical resistance, rapid gel formation, and efficient NIR-controlled drug release, offering new opportunities for biomedical applications.

Gelatin Methacryloyl (GelMA) Hydrogel Scaffolds: Predicting Physical Properties Using an Experimental Design Approach

There is a growing interest for complex in vitro environments that closely mimic the extracellular matrix and allow cells to grow in microenvironments that are closer to the one in vivo. Protein-based matrices and especially hydrogels can answer this need, thanks to their similarity with the cell microenvironment and their ease of customization. In this study, an experimental design was conducted to study the influence of synthesis parameters on the physical properties of gelatin methacryloyl (GelMA). Temperature, ratio of methacrylic anhydride over gelatin, rate of addition, and stirring speed of the reaction were studied using a Doehlert matrix. Their impact on the following parameters was analyzed: degree of substitution, mass swelling ratio, storage modulus (log(G')), and compression modulus. This study highlights that the most impactful parameter was the ratio of methacrylic anhydride over gelatin. Although, temperature affected the degree of substitution, and methacrylic anhydride addition flow rate impacted the gel's physical properties, namely, its storage modulus and compression modulus. Moreover, this experimental design proposed a theoretical model that described the variation of GelMA's physical characteristics as a function of synthesis conditions.

A lysine-based 2:1-[α/aza]-pseudopeptide series used as additives in polymeric membranes for CO2 capture: synthesis, structural studies, and application†

The current study presents for the first time the synthesis of a new 2:1-[α/aza]-pseudopeptide series possessing charged amino acids (i.e., lysine) and aims at studying the influences of chirality, backbone length, and the nature of the lysine side chains on the conformation of the 2:1-[α/aza]-oligomers in solution using NMR, FTIR spectroscopy and molecular dynamic calculations. The spectroscopic results emphasized the conservation of the β-turn conformation adopted by the trimers regardless of the chirality which demonstrated a noticeable effect on the conformation of homochiral hexamer (8c) compared with the hetero-analogue (8d). The molecular dynamic calculations predicted that the chirality and the side chain of the lysine residues caused a little distortion from the classical β-turn conformation in the case of short trimer sequences (7c and 7d), while the chirality and the backbone length exerted more distortion on the β-turn adopted by the longer hexamer sequences (8c and 8d). The large disturbance in hexamers from classical β-turn was attributed to increasing the flexibility and the possibility of molecules to adopt a more energetically favorable conformation stabilized by non-classical β-turn intramolecular hydrogen bonds. Thus, alternating d- and l-lysine amino acids in the 2:1-[α/aza]-hexamer (8d) decreases the high steric hindrance between the lysine side chains, as in the homo analogue (8c), and the distortion is less recognized. Finally, short sequences of aza-pseudopeptides containing lysine residues improve CO₂ separation when used as additives in Pebax® 1074 membranes. The best membrane performances were obtained with a pseudopeptidic dimer as an additive (6b′; deprotected lysine side chain), with an increase in both ideal selectivity α_CO2/N2 (from 42.8 to 47.6) and CO₂ permeability (from 132 to 148 Barrer) compared to the virgin Pebax® 1074 membrane.

A new 2:1-[α/aza]-pseudopeptide series based charged lysine amino acid was synthesized. Influences of chirality, backbone length, and lysine side chains on the oligomers conformation were investigated in solution using NMR, FTIR and MD calculations.

Epidemiology and impact of frailty in patients with atrial fibrillation in Europe

BACKGROUND

Frailty is a medical syndrome characterised by reduced physiological reserve and increased vulnerability to stressors. Data regarding the relationship between frailty and atrial fibrillation (AF) are still inconsistent.

OBJECTIVES

We aim to perform a comprehensive evaluation of frailty in a large European cohort of AF patients.

METHODS

A 40-item frailty index (FI) was built according to the accumulation of deficits model in the AF patients enrolled in the ESC-EHRA EORP-AF General Long-Term Registry. Association of baseline characteristics, clinical management, quality of life, healthcare resources use and risk of outcomes with frailty was examined.

RESULTS

Among 10,177 patients [mean age (standard deviation) 69.0 (11.4) years, 4,103 (40.3%) females], 6,066 (59.6%) were pre-frail and 2,172 (21.3%) were frail, whereas only 1,939 (19.1%) were considered robust. Baseline thromboembolic and bleeding risks were independently associated with increasing FI. Frail patients with AF were less likely to be treated with oral anticoagulants (OACs) (odds ratio 0.70, 95% confidence interval 0.55-0.89), especially with non-vitamin K antagonist OACs and managed with a rhythm control strategy, compared with robust patients. Increasing frailty was associated with a higher risk for all outcomes examined, with a non-linear exponential relationship. The use of OAC was associated with a lower risk of outcomes, except in patients with very/extremely high frailty.

CONCLUSIONS

In this large cohort of AF patients, there was a high burden of frailty, influencing clinical management and risk of adverse outcomes. The clinical benefit of OAC is maintained in patients with high frailty, but not in very high/extremely frail ones.

P-721 Prediction model of pregnancy after intrauterine insemination: accessibility, relevance for clinical use and patient counseling

Study question

The aim of this study is to develop a prognostic model for the outcome of intrauterine insemination that is useful for daily clinical practice and to develop an app

Summary answer

Our predictive model is able to make a good distinction between patients with a good or poor pregnancy chance

What is known already

IUI is a common, accessible and easily accepted method of treating infertile couples with a success rate varying largely between 5% and 70%.

The factors that contribute to the successful IUI rate are numerous including the woman's age, type of infertility, the number of follicles obtained by ovarian stimulation, the estradiol concentration on the day of human chorionic gonadotrophin administration, the sperm parameters (concentration, motility), duration of infertility, endometrial thickness, the number of IUI cycles.

Several studies have already tried to establish a success rate formula, but no prediction model is largely used.

Study design, size, duration

This retrospective cohort study has been conducted at an university level fertility clinic from Oradea, Romania. Patients eligible to participate in the study were 426 infertile couples who underwent IUI treatment between January 2015 and October 2020.

Participants/materials, setting, methods

The 426 couples were classified into three groups: 1. male infertility factor 2. female infertility factor (minimal/mild endometriosis, ovulation disorders, tubal disease, with a single patented Fallopian tube), 3. Unexplained infertility.

All couples underwent IUI with/or without ovarian stimulation and we documented several factors: age, type of infertility, infertility duration, number of procedures, ovarian stimulation, number of follicles, endometrial thickness, ovulation induction, day of induction, associated pathology, tubal patency, post wash sperm count.

Main results and the role of chance

Our pregnancy rate was 10.3%, according to this the couples were divided intro two groups the negative and the positive result group. We found 4 factors to be significantly associated to a positive result: age of the partners (p-value = 0.012), infertility duration (p-value = 0.018), endometrium thickness (p-value = 0.035) and semen preprocess concentration (p-value = 0.046).

We calculated a probability function for a woman to get pregnant after IUI procedure:

Prob = 1/(1+e-z)

Z = -3.36998 + 0.364*Endometrium (mm) – 0.04567*Female Age (years) – 0.049956*Age of partner (years)– 0.17299*Duration of infertility (years) + 0.018562*prewash count (mil) – 0.9933*A (motility) + 2.29085*B(motility)+ 0.03203*post wash count

For example, a patient with a score of 1.507 will have a probability of 81.86% of becoming pregnant.

Our predictive model in general has a performance that is close to 0.7 AUROC -0.687 (AUROC between 0.7-0.8 has a fair performance) with a value p-0.001 (high statistical significance, CI confidence interval - 99.9%), meaning it is able to make a good distinction between couples with a good pregnancy chance and those with a poor pregnancy chance after IUI.

Limitations, reasons for caution

In statistical models fertility treatment chances are never 0 or 100%, and the outcome of IUI is a subject to chance and from this point of view the trick would be in repeating the cycles. Another limitation is the small cohort sample and the fact that it needs external validation.

Wider implications of the findings

Developing an application program that could be used easily by the clinicians in their daily clinical practice and also by the patients in order to better understand their chances at a successful procedure of assisted human reproduction that could also mean the next step after IUI, the in vitro fertilization.

Trial registration number

not applicable

Does radiofrequency with contact force supersede cryoballoon for atrial fibrillation ablation? A one-year follow-up retrospective study

Introduction

If catheter ablation of atrial fibrillation (AF) is now proved to be a safe and superior alternative to antiarrhythmic drugs for maintenance of sinus rhythm and improvement of symptoms, the best transcatheter technique is still a matter of debate. Radiofrequency (RF) and cryoballoon (CRYO) are the principal technologies sharing the spotlight, and several observational studies and RCT have compared both techniques with conflicting results.

Purpose

Current RF catheters now use contact-force technologies to precisely calibrate the energy delivered to tissue, according to the force applied to adjacent tissue in grams, time of contact in seconds and more recently power delivered in watts. The purpose of our study is to evaluate the contribution of this technology in “real life ” conditions and its hypothetical potential to supersede CRYO for the ablation of AF.

Methods

Design and population. We conducted a single center retrospective study, spreading over two years (1st January 2018–30th December 2019) and enrolling 376 patients that underwent a first ablation procedure in this period.

Endpoints. The primary endpoint was a comparison of the rate of AF recurrence for each technique, twelve months after initial procedure, respecting an initial 90 days blanking period.

Recurrence was defined as documented AF, atrial flutter, atrial tachycardia lasting at least 30 seconds (12-lead ECG, holter or telemetry) or 6 minutes (for atrial high rate episode on pacemaker interrogation), and/or the need of a second ablation procedure.

We evaluated secondary efficacy endpoints including death, procedure duration, fluoroscopy time and hospitalization for cardiovascular causes. Complications in direct relation with the initial procedure were the primary safety endpoint. Finally, we studied the impact of five factors on recurrence: temporal pattern of AF, left atrium dimension, arrhythmia duration, body mass index and CHADS2VA2Sc score.

Results

Patients who underwent RF ablation were similar to those who underwent cryoablation except for chronic kidney disease, type 2 diabetes and coronaropathy which were more prevalent in RF group.

We found a trend toward lower incidence of recurrences in the cryoballoon group, despite not statistically significant. Hospitalizations for cardiovascular causes and deaths from any cause were slightly higher in the radiofrequency group. As expected, time of procedure was lower and fluoroscopy time higher in cryoballoon group. Significant association was detected between recurrence and both left atrium diameter and CHADS2VA2Sc score.

Conclusion

In this retrospective study, albeit using latest generation ablation catheters in the two different technics, we found no significant difference in recurrence of AF between radiofrequency and cryoballoon ablation of AF. Left atrium diameter and higher CHADS2VA2Sc score are two predictors of recurrence, easy to use in daily clinical practice.

Funding Acknowledgement

Type of funding sources: None. Baseline characteristics – endpointsPrimary efficacy end point

Cyclohexamer [-(d-Phe-azaPhe-Ala)2-]: good candidate to formulate supramolecular organogels

Molecular self-assembly is a fascinating process which has become an area of great interest in supramolecular chemistry, as it leads in certain cases to molecular gels. Organogels formulated from low molecular weight compounds (LMWOGs) have attracted much interest in the past decades due to their applications as new soft materials. Herein, we report on the ability of the cyclic pseudopeptide cyclo-[-(d-Phe-azaPhe-Ala)2-] (2) to self-assemble in some aromatic solvents and to form organogels driven by non-covalent forces, mainly hydrogen bonding and π-stacking interactions. Comprehensive FTIR and NMR studies emphasized that this cyclic aza-peptide adopts a β-turn conformation at low concentration in toluene, while an equilibrium between the monomeric states (intramolecular forces) and the supramolecular structures (intra- and intermolecular forces) is established at high concentration (gel state). Rheological investigations of the organogels highlight the dependence of their stiffness (up to ∼4 kPa) and sol/gel transition temperatures (up to 100 °C) as a function of the solvent and concentration of gelator used. The formulation of fibrous structures confirmed the phenomenon of self-assembly. Finally, we found that cyclo-[-(d-Phe-azaPhe-Ala)2-] is an effective organogelator for application in phase selective gelation (PSG) of organic solvents from aqueous/organic mixtures with recovery percents up to 96%.

Magnesium alloys and graphite wastes encapsulated in cementitious materials: Reduction of galvanic corrosion using alkali hydroxide activated blast furnace slag

Magnesium alloys and graphite from spent nuclear fuel have been stored together in La Hague plant. The packaging of these wastes is under consideration. These wastes could be mixed in a grout composed of industrially available cement (Portland, calcium aluminate…). Within the alkaline pore solution of these matrixes, magnesium alloys are imperfectly protected by a layer of Brucite resulting in a slow corrosion releasing hydrogen. As the production of this gas must be considered for the storage safety, and the quality of wasteform, it is important to select a cement matrix capable of lowering the corrosion kinetics. Many types of calcium based cements have been tested and most of them have caused strong hydrogen production when magnesium alloys and graphite are conditioned together because of galvanic corrosion. Exceptions are binders based on alkali hydroxide activated ground granulated blast furnace slag (BFS) which are presented in this article.

[A CASE OF FLECAINIDE INTOXICATION]

Flecainide acetate is an antiarrhythmic agent commonly used in clinical practice, in particular, for the treatment of supraventricular tachycardias. We report a rare case of voluntary poisoning by flecainide. The patient was successfully resuscitated.A review of the literature related to this type of intoxication is presented.

Ultra-high-Q thin-silicon nitride strip-loaded ring resonators

We report on the design, fabrication, and characterization of thin Si3N4 ultra-high-quality (UHQ) factor ring resonators monolithically integrated on a silicon chip. The devices are based on a strip-loaded configuration and operate at both near-infrared (NIR) and third-telecom wavelengths. This approach allows us to use a guiding Si3N4 core that is one order of magnitude thinner than what has been reported in the past for obtaining similar device performances. Our strip-loaded devices benefit from the absence of physically etched lateral boundaries to show minute light scattering and, therefore, reducing significantly scattering-related losses. Consequently, UHQs of 3.7×10(6) in the NIR and high-quality factors of up to 9×10(5) in the C-band were measured for the guiding material thickness of 80 nm and 115 nm, respectively. These first results are subject to further improvements that may allow employing strip-loaded resonators in nonlinear frequency conversion or quantum computing schemes within the desired spectral range provided by the material transparency.

Identifying three-way DNA junction-specific small-molecules

Three-way junction DNA (TWJ-DNA, also known as 3WJ-DNA) is an alternative secondary DNA structure comprised of three duplex-DNAs that converge towards a single point, termed the branch point. This point is characterized by unique geometrical properties that make its specific targeting by synthetic small-molecules possible. Such a targeting has already been demonstrated in the solid state but not thoroughly biophysically investigated in solution. Herein, a set of simple biophysical assays has been developed to identify TWJ-specific small-molecule ligands; these assays, inspired by the considerable body of work that has been reported to characterize the interactions between small-molecules and other higher-order DNA (notably quadruplex-DNA), have been calibrated with a known non-specific DNA binder (the porphyrin TMPyP4) and validated via the study of a small series of triazacyclononane (TACN) derivatives (metal-free or not) and the identification of a fairly-affinic and exquisitely TWJ-selective candidate (a TACN-quinoline construct named TACN-Q).

Extended applications with smart cards for integration of health care and health insurance services

In 1999 in Romania has initiated the reformation of the national health care system based on health insurance. In 1998 we analyzed this system from the point of view of its IT support and we studied methods of optimisation with relational, distributed databases and new technologies such as Our objectives were to make a model of the information and services flow in a modern health insurance system, to study the smart card technology and to demonstrate how smart card can improve health care services. The paper presents only the smart cards implementations.

Computerized system for the networking of health services (Proposed solution for the informational support of the health insurance law in Romania)

The integration of health services in the health insurance system can only be performed by using an advanced informational system, due to the large volume of documents needed for the payment of medical services by the health insurance firms. To better facilitate the access to the medical databases throughout the country is it necessary that the different application and their respective supports are able to communicate with each other. Every component of the health system (doctors' offices, clinics, hospitals, pharmacies, county health insurance offices) consist of a local LAN/WAN network according to the individual computer capabilities. These networks are connecting through the Internet which can be describe as a network of networks that permits long range communication.

Leak detection and low level monitoring of halogenated anesthetics

Halogenated compounds used in anesthetics are generally detected and monitored by gas chromatography or infrared analysis. For a quick, reliable, and economical method of detecting these compounds, the HLD-440 leak detector proved to be effective. The instrument is simple to calibrate and operate. It is safe and is capable of detecting halogenated anesthetics in concentrations at least as low as 2 parts per million.