Low Molecular Weight Research Articles

A facile strategy for tuning the density of surface-grafted biomolecules for melt extrusion-based additive manufacturing applications

AbstractMelt extrusion-based additive manufacturing (ME-AM) is a promising technique to fabricate porous scaffolds for tissue engineering applications. However, most synthetic semicrystalline polymers do not possess the intrinsic biological activity required to control cell fate. Grafting of biomolecules on polymeric surfaces of AM scaffolds enhances the bioactivity of a construct; however, there are limited strategies available to control the surface density. Here, we report a strategy to tune the surface density of bioactive groups by blending a low molecular weight poly(ε-caprolactone)5k (PCL5k) containing orthogonally reactive azide groups with an unfunctionalized high molecular weight PCL75k at different ratios. Stable porous three-dimensional (3D) scaffolds were then fabricated using a high weight percentage (75 wt.%) of the low molecular weight PCL5k. As a proof-of-concept test, we prepared films of three different mass ratios of low and high molecular weight polymers with a thermopress and reacted with an alkynated fluorescent model compound on the surface, yielding a density of 201–561 pmol/cm2. Subsequently, a bone morphogenetic protein 2 (BMP-2)-derived peptide was grafted onto the films comprising different blend compositions, and the effect of peptide surface density on the osteogenic differentiation of human mesenchymal stromal cells (hMSCs) was assessed. After two weeks of culturing in a basic medium, cells expressed higher levels of BMP receptor II (BMPRII) on films with the conjugated peptide. In addition, we found that alkaline phosphatase activity was only significantly enhanced on films containing the highest peptide density (i.e., 561 pmol/cm2), indicating the importance of the surface density. Taken together, these results emphasize that the density of surface peptides on cell differentiation must be considered at the cell-material interface. Moreover, we have presented a viable strategy for ME-AM community that desires to tune the bulk and surface functionality via blending of (modified) polymers. Furthermore, the use of alkyne–azide “click” chemistry enables spatial control over bioconjugation of many tissue-specific moieties, making this approach a versatile strategy for tissue engineering applications. Graphic abstract

Lipopolysaccharide with long O-antigen is crucial for Salmonella Enteritidis to evade complement activity and to facilitate bacterial survival in vivo in the Galleria mellonella infection model

Bacterial resistance to serum is a key virulence factor for the development of systemic infections. The amount of lipopolysaccharide (LPS) and the O-antigen chain length distribution on the outer membrane, predispose Salmonella to escape complement-mediated killing. In Salmonella enterica serovar Enteritidis (S. Enteritidis) a modal distribution of the LPS O-antigen length can be observed. It is characterized by the presence of distinct fractions: low molecular weight LPS, long LPS and very long LPS. In the present work, we investigated the effect of the O-antigen modal length composition of LPS molecules on the surface of S. Enteritidis cells on its ability to evade host complement responses. Therefore, we examined systematically, by using specific deletion mutants, roles of different O-antigen fractions in complement evasion. We developed a method to analyze the average LPS lengths and investigated the interaction of the bacteria and isolated LPS molecules with complement components. Additionally, we assessed the aspect of LPS O-antigen chain length distribution in S. Enteritidis virulence in vivo in the Galleria mellonella infection model. The obtained results of the measurements of the average LPS length confirmed that the method is suitable for measuring the average LPS length in bacterial cells as well as isolated LPS molecules and allows the comparison between strains. In contrast to earlier studies we have used much more precise methodology to assess the LPS molecules average length and modal distribution, also conducted more subtle analysis of complement system activation by lipopolysaccharides of various molecular mass. Data obtained in the complement activation assays clearly demonstrated that S. Enteritidis bacteria require LPS with long O-antigen to resist the complement system and to survive in the G. mellonella infection model.

Pelvic vein thrombosis in patients with pelvic venous disorders.

To assess the incidence of pelvic vein thrombosis (PVT) and outcomes of anticoagulant therapy for PVT in patients with pelvic venous disorders (PeVDs). This prospective cohort study included 588 female patients with PeVDs underwent clinical examination followed by duplex ultrasound of the pelvic veins in 2021-2023. Patients with PVT were administered with anticoagulant therapy in an outpatient setting using low molecular weight heparins at a therapeutic dose. PVT was detected in 7.6% of patients with PeVDs and was symptomatic in 28.8% of them. The majority of asymptomatic patients had thrombosis in only one of the parametrial veins (90.6%). Anticoagulant therapy resulted in the PVT symptoms relief in all patients within 10 days and recanalization of the pelvic veins in 1-3 months. In our study, PVT was diagnosed in 7.6% of patients with PeVDs. Anticoagulant therapy is effective and safe in resolving PVT symptoms.

Meta-analysis of new intervention measures for preventing side effects of artificial joint replacement

BACKGROUND Intertrochanteric fracture of the femur occurs mostly among older people, and seriously affects daily life and quality of life. At present, physical intervention, drug treatment, routine intervention and rehabilitation training are widely used for prevention of side effects, but it is still inconclusive which intervention has the best effect. AIM To compare the effects of new intervention measures for preventing side effects of artificial joint replacement. METHODS We searched the Chinese and English literatures for comparative studies on the prevention of side effects of new interventions for artificial joint replacement from July 2013 to June 2023 in China HowNet, PubMed, Wanfang, Weipu and other databases. Study quality was evaluated by improved Jadad scoring standard, and the effects of different interventions on preventing different complications were analyzed by meta-analysis of evidence-based medicine with Review Manager 5.0 software. RESULTS Ten articles, including 869 cases, were finally included. The preventive effects of different interventions on the side effects of artificial joint replacement were studied, and valid data were extracted. There were two articles on the preventive effects of drug intervention, four on comparison of the preventive effects of combined and single interventions, and three on the preventive effects of physical intervention, rehabilitation training and routine intervention. Meta-analysis showed that the preventive effect of rivaroxaban was significantly better than low molecular weight heparin calcium [mean difference (MD) = -0.16, 95%CI: -0.28 to -0.04, P < 0.05]. The effect of combined intervention was significantly better than that of single intervention (MD = -0.08, 95%CI: -0.16 to -0.01, P < 0.001). Physical intervention was significantly better than routine intervention and rehabilitation training (MD = 0.26, 95%CI: 0.16–0.36, P < 0.001). CONCLUSION Rivaroxaban combined with rehabilitation training is preferred for preventing deep vein thrombosis after artificial joint replacement. In the prevention of pulmonary embolism, rivaroxaban drug intervention is given priority. The effect of combined intervention is better than that of single intervention.

Novel catalyst-solvent system for high molecular weight polylactic acid synthesis via azeotropic solution polycondensation method

ABSTRACT Polycondensation for PLA synthesis is widely used due to its cost-effectiveness, but it often leads to low molecular weight PLA. To address this limitation, researchers have explored different catalysts, with the stannous chloride and p-toluene sulfonic acid combination being a popular choice. However, this method typically yields PLA with a MW of no more than 35000 g/mol, which is unsuitable for commercial applications. In contrast, ring-opening polymerization is considered the most effective method for synthesizing high MW PLA, despite its complexity and cost. Industrial-scale production predominantly employs ROP due to its capability to produce high MW PLA. The use of stannous octoate as a catalyst for ROP has shown promise in synthesizing higher MW PLA. However, its sensitivity to water limits its use in polycondensation, where stannous chloride is commonly employed but is not capable of synthesizing high MW PLA. This study explores the use of stannous octoate for the synthesis of high MW PLA with higher yield.

Influence of Carboxymethyl Cellulose as a Thickening Agent for Glauber’s Salt-Based Low Temperature PCM

This work is focused on a novel, promising low temperature phase change material (PCM), based on the eutectic Glauber’s salt composition. To allow phase transition within the refrigeration range of temperatures of +5 °C to +12 °C, combined with a high repeatability of melting–freezing processes, and minimized subcooling, the application of three variants of sodium carboxymethyl cellulose (Na-CMC) with distinct molecular weights (700,000, 250,000, and 90,000) is considered. The primary objective is to optimize the stabilization of this eutectic PCM formulation, while maintaining the desired enthalpy level. Preparation methods are refined to ensure repeatability in mixing components, thereby optimizing performance and stability. Additionally, the influence of Na-CMC molecular weight on stabilization is examined through differential scanning calorimetry (DSC), T-history, and rheology tests. The PCM formulation of interest builds upon prior research in which borax, ammonium chloride, and potassium chloride were used as additives to sodium sulfate decahydrate (Glauber’s salt), prioritizing environmentally responsible materials. The results reveal that CMC with molecular weights of 250 kg/mol and 90 kg/mol effectively stabilize the PCM without phase separation issues, slowing crystallization kinetics. Conversely, CMC of 700 kg/mol proved ineffective due to the disruption of gel formation at its low gel point, hindering higher concentrations. Calculations of ionic concentration indicate higher Na ion content in PCM stabilized with 90 kg/mol CMC, suggesting increased ionic interactions and gel strength. A tradeoff is discovered between the faster crystallization in lower molecular weight CMC and the higher concentration required, which increases the amount of inert material that does not participate in the phase transition. After thermal cycling, the best formulation had a latent heat of 130 J/g with no supercooling, demonstrating excellent performance. This work advances PCM’s reliability as a thermal energy storage solution for diverse applications and highlights the complex relationship between Na-CMC molecular weight and PCM stabilization.

Source identification of polycyclic aromatic hydrocarbons (PAHs) in soils around crude oil contaminated area in Ohaji/Egbema, Imo State

ABSTRACT This study aims to determine the source of polycyclic aromatic hydrocarbons (PAHs) in the soils surrounding an area in Ohaji/Egbema, Imo State, that has been contaminated by crude oil. Soil samples were collected in the study area using a soil auger at a depth of 0–20 cm at three sampling locations (sample A, sample B, and sample C) in the Mmahu community in Ohaji/Egbema. In each of the sampling locations, twenty sub-samples were collected from twenty sampling points and pooled together to form representative samples for each of the sampling locations. Prior to GC-MS analysis, the composite samples were air-dried, sieved through a 2-mm mesh, and then kept in pet bottles that had been previously cleaned. The GC-MS investigations were carried out using a Shimadzu Model 2010 GC-MS (Shimadzu, Japan) fitted with an HP-5 MS fused silica column. This was used to quantify the 16 USEPA priority PAHs in the studied soils. The sum of the 16 USEPA priority PAHs in the sample locations ranged from 0.0192 mg/kg in the control sample to 10.73 mg/kg in sample A. Compared to high molecular weight PAHs (4–6 rings), the total concentration of low molecular weight PAHs (2–3 rings) was found to be substantially greater. According to the PAH molecular diagnostic ratio, all sampling points had low to high molecular mass ratios >1, which suggests that the origin of the PAH contamination was petrogenic. The petrogenic source of contamination was attributed to oil spillage around the study area. The knowledge of source identification of PAHs in soils helps in the determination of the most appropriate remediation strategy in order to prevent further contamination and minimise the risks to human health and the environment.

Synthesis of Membrane-Permeable Macrocyclic Peptides via Imidazopyridinium Grafting.

Macrocyclic peptides (MPs) are a class of compounds that have been shown to be particularly well suited for engaging difficult protein targets. However, their utility is limited by their generally poor cell permeability and bioavailability. Here, we report an efficient solid-phase synthesis of novel MPs by trapping a reversible intramolecular imine linkage with a 2-formyl- or 2-keto-pyridine to create an imidazopyridinium (IP+)-linked ring. This chemistry is useful for the creation of macrocycles of different sizes and geometries, including head-to-side and side-to-side chain configurations. Many of the IP+-linked MPs exhibit far better passive membrane permeability than expected for "beyond Rule of 5" molecules, in some cases exceeding that of much lower molecular weight, traditional drug molecules. We demonstrate that this chemistry is suitable for the creation of libraries of IP+-linked MPs and show that these libraries can be mined for protein ligands.

The Emulsification and Stabilization Mechanism of an Oil-in-Water Emulsion Constructed from Tremella Polysaccharide and Citrus Pectin

The objective of this study was to investigate the feasibility of the mixture of tremella polysaccharide (TP) and citrus pectin (CP) as an emulsifier by evaluating its emulsifying ability/stability. The results showed that the TP:CP ratio of 5:5 (w/w) could effectively act as an emulsifier. CP, owing its lower molecular weight and highly methyl esterification, facilitated the emulsification of oil droplets, thereby promoting the dispersion of droplets. Meanwhile, the presence of TP enhanced the viscosity of emulsion system and increased the electrostatic interactions and steric hindrance, therefore hindering the migration of emulsion droplets, reducing emulsion droplets coalesce, and enhancing emulsion stability. The emulsification and stabilization performances were influenced by the molecular weight, esterified carboxyl groups content, and electric charge of TP and CP, and the potential mechanism involved their impact on the buoyant force of droplet size, viscosity, and steric hindrance of emulsion system. The emulsions stabilized by TP-CP exhibited robust environmental tolerance, but demonstrated sensitivity to Ca2+. Conclusively, the study demonstrated the potential application of the mixture of TP and CP as a natural polysaccharide emulsifier.

AN ACUTE MYOCARDIAL INFARCTION IN A VERY YOUNG MAN DUE TO HYPERHOMOCYSTEINEMIA

Abstract Introduction A young 17–year–old boy smoker and obese was admitted to our cardiology unit for continuous oppressive chest pain radiating to the left arm that had arisen three days earlier. In the emergency room, he had performed blood tests with evidence of an increased troponin and an electrocardiogram that showed mild ST–elevation in inferior leads with ST depression in aVL. We performed an urgent transthoracic echocardiography examination that was unremarkable Investigation Once diagnosed with acute ST–segment elevation myocardial infarction, the patient underwent emergency coronary angiography. Coronary angiography highlighted an intermediate stenosis of the first branch diagonal to the proximal tract and a possible occlusion of the periapical branch of the anterior descending artery. It was decided not to perform PTCA as we could not exclude a distal coronary dissection and considering the vessel was of small caliber. We decided to complete the diagnostic process by performing a cardiac MRI showing edema in the apex and distal inferior wall and transmural gadolinium enhancement at the level of the septum and inferior wall of the distal section. In the context of the damaged wall a focal area of hypointensity to be referred to the "no–reflow" phenomenon Management The patient was treated with DAPT, low molecular weight heparin and high dose statin. A few hours after the coronary angiography the patient stopped having chest pain and remained asymptomatic for the rest of the hospital stay. We performed complete blood tests including with evidence of hyperhomocysteinemia. The lipid panel was normal. Hematological consultation recommended folate and Vitamine B12 treatment. After 12 months the patient is asymptomatic, has stopped smoking and continues to take DAPT. He repeated the echocardiogram which showed no alterations. Genetic testing was performed after hospital discharge and was positive for Methylenetetrahydrofolate reductase (MTHFR) homozygous mutation Conclusion Our clinical case shows a rare case of acute myocardial infarction in a very young person. Diagnosis and treatment were complicated by the extreme distality of the occlusion and the few modifiable risk factors identified (smoker, obesity and hyperhomocysteinemia). Hyperhomocysteinemia is an often underestimated cardiovascular risk factor associated with a high risk of cardiovascular events and multivessel coronary disease that should be sought in all young patients with AMI.

BETWEEN SCYLLA AND CHARYBDIS: MULTIPLE LEFT ATRIAL THROMBI DESPITE ORAL ANTICOAGULATION AND ANTIPLATELET THERAPY IN A PATIENT CANDIDATE FOR LEFT ATRIAL APPENDAGE OCCLUSION

Abstract Introduction Left atrial (LA) thrombosis usually occurs in patients affected by atrial fibrillation (AF), generally involving the left atrial appendage (LAA). We present the unexpected echocardiographic finding of multiple LA thrombi despite an adequate antithrombotic strategy. Case Presentation A 76–year–old lady underwent transesophageal echocardiographic examination (TOE) to assess eligibility for percutaneous LAA occlusion (LAAO) procedure due to high bleeding risk. Her medical history included AF and a recent percutaneous coronary revascularization; therefore, her antithrombotic therapy included apixaban 2.5 mg bid and clopidogrel 75 mg od. The TOE showed LA structural and functional remodeling with spontaneous echo contrast and multiple thrombi involving the LAA (one [12 x 9 mm] overflowing the orifice and attached to the Coumadin Ridge and the second [12 x 7 mm] attached and arising from the tunnel of patent foramen ovale). Mitral valve stenosis was excluded (Fig.1). Due to TOE findings, the patient was not considered eligible for percutaneous LAAO. Due to the concomitant very high thromboembolic risk, despite the previous intracranial bleeding, we decided to stop apixaban and to start parenteral anticoagulation for 3 weeks with low–molecular weight heparin (100 UI/kg bid) followed by the switch to a vitamin k antagonist (VKA). We also prescribed a hematological evaluation to exclude a hypercoagulability disorder. Our patient’s daughter was a carrier of a mutation in both the methylenetetrahydrofolatereductase and Thrombin genes. A TOE after 30 days showed the persistence of LA thrombi, although with significantly reduced size and mobility (Fig.2). The follow–up was clinically uneventful. We suggested to continue anticoagulation therapy with VKA, and we planned a new TOE after 4 weeks. Discussion Although proper anticoagulation decreases cardioembolic risk in patients with AF, atrial thrombosis may occur due to LA remodeling, high CHA2DS2–VASc score and other factors, including hypercoagulability disorders. The presence of multiple LA thrombi represents a challenge for clinicians, especially in case of concomitant high thromboembolic and bleeding risk. However, the best treatment strategies for these extreme conditions are not defined, so far. Therefore, the therapeutic choice is often tailored to the single patient and based on the clinical judgment, bearing in mind that avoiding Charybdis means passing to close to Scylla and vice versa.

[68Ga]Ga-NODAGA-TriGalactan, a low molecular weight tracer for the non-invasive imaging of the functional liver reserve

BackgroundDetermination of the functional liver mass is important in a variety of clinical settings including liver surgery and transplantation. [99mTc]Tc-diethylenetriamine-pentaacetic acid galactosyl human serum albumin (99mTc-GSA) is a radiotracer targeting the asialoglycoprotein receptor (ASGR) and is routinely used in Japan for this purpose. Here we describe the development and evaluation of [68Ga]Ga-NODAGA-TriGalactan a low molecular weight PET-tracer targeting this structure.ResultsFor synthesis TRIS as branching unit and NODAGA as chelator for labelling with [68Ga]Ga are included. Three galactose moieties are conjugated via a click chemistry approach resulting in the desired labelling precursor.68Ga-labelling could be accomplished in high radiochemical yield and purity. [68Ga]Ga-NODAGA-TriGalactan is very hydrophilic and revealed high plasma stability and low plasma protein binding. Fluorescence imaging showed binding on ASGR-positive organoids and the IC50-value was in the nanomolar range. Most importantly, both biodistribution as well as animal imaging studies using normal mice demonstrated high liver uptake with rapid elimination from all other organs leading to even higher liver-to-background ratios as found for 99mTc-GSA.Conclusion[68Ga]Ga-NODAGA-TriGalactan shows high in vitro stability and selectively binds to the ASGR allowing imaging of the functional liver mass with high contrast. Thus, our first generation compound resulted already in an alternative to 99mTc-GSA for imaging the functional liver reserve and might allow the broader use of this imaging technique.

Bio-based protic salts as precursors for sustainable free-standing film electrodes

Transforming amines with low boiling points and high volatilities into protic salts is a versatile strategy to utilize low molecular weight compounds as precursors for N-doped carbon structures in a straightforward carbonization procedure. Herein, conventional mineral acids commonly used for the synthesis of protic salts were replaced by bio-derived phytic acid, which, combined with various amines and amino acids, yielded partially or fully bio-derived protic salts. The biomass-based salts showed higher char-forming ability than their mineral acid-based analogs (up to 55.9% at 800°), simultaneously providing carbon materials with significant porosity (up to 1177 m2g−1) and a considerable level of N,P,O-doping. Here, we present the first comprehensive study on the correlation between the structure of the bio-derived protic precursors and the properties of derived carbon materials to guide future designs of biomass-derived precursors for the one-step synthesis of sustainable carbon materials. Additionally, we demonstrate how to improve the textural properties of the protic-salt-derived carbons (which suffer from high brittleness) by simply upgrading them into highly flexible nanocomposites using high-quality single-walled carbon nanotubes. Consequently, self-standing electrodes for the oxygen reduction reaction were created.

Towards Sustainable Viscose-to-Viscose Production: Strategies for Recycling of Viscose Fibres

The potential for using discarded viscose textiles to produce high-quality viscose fibres is limited by the low molecular weight of the cellulose and its continued reduction in the recycling process. Herein, we present a straightforward approach of reprocessing discarded viscose textiles while achieving high-quality recycled viscose fibres. Discarded viscose textile was defibrated and centrifuged, and the resulting fibres were reprocessed under industrially relevant conditions. The produced viscose dope was fluid and resulted in viscose fibres with properties comparable to fibres made from commercial wood cellulose pulp (titer ~2 dtex; dry elongation ~16%, dry tenacity ~15 cN/tex). To explore the potential for a more environmentally friendly production process, the steeping step was performed twice (double-steeping), thereby producing a more homogeneous viscose dope. Through double-steeping, the consumption of carbon disulfide (CS2) could be reduced by 30.5%. The double-steeping method shows to be a suitable approach to reprocess discarded viscose textiles while reducing the environmental impact of the viscose process associated with the use of CS2. Our work demonstrates that discarded viscose textile has the potential to be part of a circular textile value chain.

Daphnia magna model for the study of mycotoxins present in food: Gliotoxin, ochratoxin A and its combination

Mycotoxins are low molecular weight compounds present in food and feed. Although their effects on human health have been widely described, their mechanisms of action are still undefined. Gliotoxin (GTX) and ochratoxin A (OTA) are among the most dangerous mycotoxins produced by Aspergillus spp. Therefore, their toxicity was studied in the Daphnia magna model, which has high capacity to predict cytotoxicity and assess ecotoxicity, comparable to mammalian models. The study consisted of a series of tests to evaluate the effects of mycotoxins GTX, OTA and their combinations at different dilutions on Daphnia magna that were conducted according to standardized OECD 202 and 211 guidelines. The following assays were carried out: acute toxicity test, heartbeat, delayed toxicity test, reproduction, growth rate test. Reproducibility was determined by observing the offspring after 21 days of GTX exposure. In acute and delayed toxicity transcript levels of genes involved in xenobiotic metabolism (mox, gst, abcb1, and abcc5), and oxidative stress (vtg-SOD) were analyzed by qPCR. GTX showed acute toxicity and decreased heart rate in D. magna compared to OTA. On the other hand, OTA showed a delayed effect as evidenced by the immobility test. Both mycotoxins showed to increase genes involved in xenobiotic metabolism, while only the mycotoxin mixture increased oxidative stress. These results suggest that the mycotoxins tested could have negative impact on the environment and human health.

Association of timing and agent for VTE prophylaxis in patients with severe traumatic brain injury on VTE, mortality, neurosurgical intervention, and discharge disposition.

Trauma patients are at increased risk for venous thromboembolism events (VTE). The decision of when to initiate VTE chemoprophylaxis (VTEP) and with what agent remains controversial in patients with severe traumatic brain injury (TBI). This comparative effectiveness study evaluated the impact of timing and agent for VTEP on outcomes for patients with severe TBI (AIS Head = 3,4, or 5). Data was collected at 35 Level 1 and 2 trauma centers from January 1, 2017 to June 1, 2022. Patients were placed into analysis cohorts: No VTEP, low-molecular weight heparin (LMWH) ≤ 48 hours, LMWH>48 hours, Heparin≤48 hours, Heparin>48 hours. Propensity score matching accounting for patient factors and injury characteristics was used with logistic regression modeling to evaluate in-hospital mortality, VTE events, and discharge disposition. Neurosurgical intervention after initiation of VTEP was used to evaluate extension of intracranial hemorrhage. Of 12,879 patients, 32% had no VTEP, 36% LMWH, and 32% Heparin. Overall mortality was 8.3% and lowest among patients receiving LMWH≤48 hours (4.1%). VTE rates were lower with use of LMWH (1.6 vs 4.5%, OR 2.98, 95% CI 1.40-6.34, p = 0.005) without increasing mortality or neurosurgical interventions. VTE rates were lower with early prophylaxis (2.0 vs 3.5%, OR 1.76, 95% CI 1.15-2.71, p = 0.01) without increasing mortality (p = 1.0). Early VTEP was associated with more non-fatal intracranial operations (p < 0.001). However, patients undergoing neurosurgical intervention after VTEP initiation had no difference in rates of mortality, withdrawal of care, or unfavorable discharge disposition (p = 0.7, p = 0.1, p = 0.5). In patients with severe TBI, LMWH usage was associated with lower VTE incidence without increasing mortality or neurosurgical interventions. Initiation of VTEP≤48 hours decreased VTE incidence and increased non-fatal neurosurgical interventions without affecting mortality. LMWH is the preferred VTEP agent for severe TBI, and initiation ≤48 hours should be considered in relation to these risks and benefits. Therapeutic/Care Management, Level III.

Collagen-Mesenchymal Stem Cell Microspheres Embedded in Hyaluronic Acid Solutions as Biphasic Stem Niche Delivery Systems for Pulmonary Differentiation.

Cell therapy has the potential to become a feasible solution for several diseases, such as those related to the lungs and airways, considering the more beneficial intratracheal administration route. However, in lung diseases, an impaired pulmonary extracellular matrix (ECM) precludes injury resolution with a faulty engraftment of mesenchymal stem cells (MSCs) at the lung level. Furthermore, a shielding strategy to avoid cell damage as well as cell loss due to backflow through the injection path is required. Here, an approach to deliver cells encapsulated in a biomimetic stem niche is used, in which the interplay between cells and physiological lung ECM constituents, such as collagen and hyaluronic acid (HA), can occur. To this aim, a biphasic delivery system based on MSCs encapsulated in collagen microspheres (mCOLLs) without chemical modification and embedded in an injectable HA solution has been developed. Such biphasic delivery systems can both increase the mucoadhesive properties at the site of interest and improve cell viability and pulmonary differentiation. Rheological results showed a similar viscosity at high shear rates compared to the MSC suspension used in intratracheal administration. The size of the mCOLLs can be controlled, resulting in a lower value of 200 μm, suitable for delivery in alveolar sacs. Biological results showed that mCOLLs maintained good cell viability, and when they were suspended in lung medium implemented with low molecular weight HA, the differentiation ability of the MSCs was further enhanced compared to their differentiation ability in only lung medium. Overall, the results showed that this strategy has the potential to improve the delivery and viability of MSCs, along with their differentiation ability, in the pulmonary lineage.

Exploration and Purification of Secondary Metabolites from Lactobacillus acidophilus and Their Potential as a Bio-preservative

The natural tendency of many food items to spoil requires the use of natural preservatives to extend shelf life while maintaining their original qualities, such as texture and flavour. Consequently, there's a rising demand for preservatives derived from organic sources. This research focused on producing a bioactive compound with a low molecular weight using Lactobacillus acidophilus (MTCC 10307). The study investigated how different production mediums, temperatures, and pH levels influenced the synthesis process. With optimized conditions, the molecule was synthesized, extracted, purified, and characterized. UV analysis detected an absorption peak characteristic of a proteinaceous substance in the extracted material. The isolated compound was then tested for its antibacterial activity against foodborne pathogens. By utilizing the isolated component as a bio-preservative in various types of juices, its effect on shelf life was assessed. One advantage of a low molecular weight compound is its ability to quickly penetrate cell walls and combat bacteria responsible for food spoilage.

Contamination Levels and Accumulation Profiles of Polycyclic Aromatic Hydrocarbons (PAHs) in Surface Sediments from South Central Coast of Vietnam

Polycyclic aromatic hydrocarbons (PAHs) are typical organic pollutants of great concern due to their negative impacts on environmental and human health. The less polar and hydrophobic nature of PAHs is responsible for their ability to adsorb onto suspended particles and to accumulate in sediments. In this study, surface sediment samples were collected in the South Central Coast of Binh Dinh Province, Vietnam to determine concentrations of 16 PAHs. The sediment samples were directly ultrasound extracted with a mixture of acetone/hexane (1:1) and toluene. The extract was purified on a chromatographic column containing activated silica gel with dichloromethane/hexane (1:3) as elution solvent. PAHs were separated and quantified on a gas chromatography/mass spectrometry (GC/MS) system with a DB-5ms column. The MS detector was operated in electron impact ionization (EI) mode and ion selective monitoring (SIM) mode. Levels of 16 PAHs ranged from 33.1 to 196 (mean 80.0) nanograms per gram sediment (ng/g). In all sediment samples, proportions of high molecular weight PAHs (4-6 rings, 63–88%) were higher than those of low molecular weight PAHs (2-3 rings, 12–37%), indicating that emission sources are mainly related to thermal processes rather than petroleum products. The most predominant substances were: Pyr (14% ± 3%), Flt (12% ± 3%), Phe (10% ± 3%), Chr (9% ± 2%), and BaP (9% ± 3%). Further studies on the pollution status of PAHs and their derivatives in Vietnamese marine environments are essential.

Interaction of heparin with human cardiac troponin complex and its influence on the immunodetection of troponins in human blood samples.

Heparin is a highly charged polysaccharide used as an anticoagulant to prevent blood coagulation in patients with presumed myocardial infarction and to prepare heparin plasma samples for laboratory tests. There are conflicting data regarding the effects of heparin on the measurement of cardiac isoforms of troponin I (cTnI) and troponin T (cTnT), which are used for the immunodiagnosis of acute myocardial infarction. In this study, we investigated the influence of heparin on the immunodetection of human cardiac troponins. Gel filtration (GF) techniques and sandwich fluoroimmunoassay were performed. The regions of сTnI and cTnT that are affected by heparin were investigated with a panel of anti-cTnI and anti-cTnT monoclonal antibodies, specific to different epitopes. Heparin was shown to bind to the human cardiac full-size ternary troponin complex (ITC-complex) and free cTnT, which increased their apparent molecular weights in GF studies. Heparin did not bind to the low molecular weight ITC-complex and to binary cTnI-troponin С complex. We did not detect any sites on cTnI in the ITC-complex that were specifically affected by heparin. In contrast, cTnT regions limited to approximately 69-99, 119-138 and 145-164 amino acid residues (aar) in the ITC-complex and a region that lies approximately between 236 and 255 aar of free cTnT were prone to heparin influence. Heparin binds to the ITC-complex via cTnT, interacting with several sites on the N-terminal and/or central parts of the cTnT molecule, which might influence the immunodetection of analytes in human blood.