Polysaccharide-Targeting Lipid Nanoparticles to Kill Gram-Negative Bacteria.

The rapid increase and spread of Gram-negative bacteria resistant to many or all existing treatments threaten a return to the preantibiotic era. The presence of bacterial polysaccharides that impede the penetration of many antimicrobials and protect them from the innate immune system contributes to resistance and pathogenicity. No currently approved antibiotics target the polysaccharide regions of microbes. Here, describe monolaurin-based niosomes, the first lipid nanoparticles that can eliminate bacterial polysaccharides from hypervirulent Klebsiella pneumoniae, are described. Their combination with polymyxin B shows no cytotoxicity in vitro and is highly effective in combating K. pneumoniae infection in vivo. Comprehensive mechanistic studies have revealed that antimicrobial activity proceeds via a multimodal mechanism. Initially, lipid nanoparticles disrupt polysaccharides, then outer and inner membranes are destabilized and destroyed by polymyxin B, resulting in synergistic cell lysis. This novel lipidic nanoparticle system shows tremendous promise as a highly effective antimicrobial treatment targeting multidrug-resistant Gram-negative pathogens.

Gelofusine Ameliorates Colistin-Induced Nephrotoxicity.

Colistin therapy is used as the last line of defense against life-threatening Gram-negative infections. Nephrotoxicity is the major dose-limiting side effect that impedes optimal dosing of patients. This study aims to examine the nephroprotective effect of the plasma volume expander gelofusine against colistin-induced nephrotoxicity. Renal protection was assessed in mice that were subcutaneously injected with colistin sulfate (14 mg/kg of body weight × 6 doses every 2 h; accumulated dose, 84 mg/kg) and simultaneously injected in the intraperitoneal region with gelofusine (75, 150, 300, or 600 mg/kg × 6). At 2 and 20 h after the last colistin dose, mice were euthanized, and the severity of renal alteration was examined histologically. Histological findings in mice revealed that colistin-induced nephrotoxicity was ameliorated by gelofusine in a dose-dependent manner, whereas significant histological abnormalities were detected in the kidneys of mice in the colistin-only group. The impact of coadministered gelofusine on colistin pharmacokinetics was investigated in rats. Rats were administered a single intravenous dose of gelofusine at 400 mg/kg 15 min prior to the intravenous administration of colistin (1 mg/kg). Gelofusine codosing did not alter the pharmacokinetics of colistin in rats; however, gelofusine did significantly lower the accumulation of colistin in the kidney tissue of mice. This is the first study demonstrating the protective effect of gelofusine against colistin-induced nephrotoxicity. These findings highlight the clinical potential of gelofusine as a safe adjunct for ameliorating the nephrotoxicity and increasing the therapeutic index of polymyxins.

Gut microbiota, a key to understanding the knowledge gaps on micro-nanoplastics-related biological effects and biodegradation.

Micro-nanoplastics (MNPs) pollution as a global environmental issue has received increasing interest in recent years. MNPs can enter and accumulate in the organisms including human beings mainly via ingestion and inhalation, and large amounts of foodborne MNPs have been frequently detected in human intestinal tracts and fecal samples. MNPs regulate the structure composition and metabolic functions of gut microbiota, which may cause the imbalance of intestinal ecosystems of the hosts and further mediate the occurrence and development of various diseases. In addition, a growing number of MNPs-degrading strains have been isolated from organismal feces. MNPs-degraders colonize the plastic surfaces and form the biofilms, and the long-chain polymers of MNPs can be biologically depolymerized into short chains. In general, MNPs are gradually degraded into small molecule substances (e.g., N2, CH4, H2O, and CO2) via a series of enzymatic catalyses, mainly including biodeterioration, fragmentation, assimilation, and mineralization. In this review, we outline the current progress of MNPs effects on gut microbiota and MNPs degradation by gut microbiota, which provide a certain theoretical basis for fully understanding the knowledge gaps on MNPs-related biological effect and biodegradation.

The effects of combined application of transcranial magnetic stimulation and language training on children with language retardation.

BACKGROUND: The objective of the present manuscript was to explore the effects of combined application of transcranial magnetic stimulation (TMS) and language training on children with language retardation. METHODS: Forty-five children with language retardation were selected as subjects and randomly divided into the treatment group with 24 patients and the control group with 21 patients. The control group was treated with traditional language training, while the treatment group was treated with TMS combined with language training. According to the Gesell pediatric neuropsychological development schedules, the development quotient of children in the two groups were observed and compared before and after two courses of treatment. The evaluation of mouth movement was conducted with Dr. Speech supervised by East China Normal University. RESULTS: Development quotient scores and mouth movement evaluation scores of all Gesell parameters of children in the two groups after treatment were significantly higher than those before treatment (P<0.05). The body movement ability, linguistic competence, development quotient scores, and mouth movement evaluation scores in the treatment group after treatment were higher than those of the control group, and the differences were statistically significant (P<0.05). CONCLUSIONS: The combined application of TMS and language training can effectively improve linguistic competence, action ability, and mouth movement in children with language retardation.

Sustained release of peptides and proteins from polymeric nanocarriers produced by inverse Flash NanoPrecipitation.

Peptide and protein therapeutics generally exhibit high potency and specificity and are increasingly important segments of the pharmaceutical market. However, their clinical applications are limited by rapid clearance and poor membrane permeability. Encapsulation of the peptide or protein into a nano-scale carrier can modify its pharmacokinetics and biodistribution. This might be employed to promote uptake in desired cell types or tissues, to limit systemic exposure, or to reduce the need for frequent injections. We have recently described inverse Flash NanoPrecipitation (iFNP), a scalable technique to encapsulate water-soluble therapeutics into polymeric nanocarriers, and have demonstrated improvements in therapeutic loading of an order of magnitude over comparable approaches. Here, we describe the formulation parameters that control release rates of encapsulated model therapeutics polymyxin B, lysozyme, and bovine serum albumin from nanocarriers produced using iFNP. Using a neutropenic lung infection mouse model with a multi-drug resistant Acinetobacter baumannii clinical isolate, we demonstrate enhanced therapeutic effect and safety profile afforded by nanocarrier-encapsulated polymyxin B following pulmonary administration. The encapsulated formulation reduced toxicity observed at elevated doses and resulted in up to 2.7-log10 reduction in bacterial burden below that of unencapsulated polymyxin B. These results establish the promise of iFNP as a platform for nanocarrier delivery of water-soluble therapeutics.

Controlled Hydration, Transition, and Drug Release Realized by Adjusting Layer Thickness in Alginate-Ca2+/poly(N-isopropylacrylamide) Interpenetrating Polymeric Network Hydrogels on Cotton Fabrics.

The controlled hydration, transition, and drug release are realized by adjusting layer thickness in thermoresponsive interpenetrating polymeric network (IPN) hydrogels on cotton fabrics. IPN hydrogels are synthesized by sodium alginate (SA) and poly(N-isopropylacrylamide) (PNIPAM) with a ratio of 1:5/% (w/v). The cotton-fabric-supported IPN hydrogels with a thickness of 1000 µm exhibit a transition temperature (TT) at 35.2 °C. When the hydrogel thicknesses are thinned to 500 and 250 µm, the TTs are reduced to 34.8 and 34.1 °C, respectively. Interestingly, the morphology of IPN hydrogels switches from a well-defined honeycomb-like network structure (1000 µm) to a densely packed layer structure (250 µm). The thinner layers not only present a smaller extent of hydration and collapse but also require longer time to reach an equilibrium state, which can be attributed to the more pronounced hindrance of the chain rearrangement by the cotton fabrics. To address the influence of layer thickness on the drug release, we compare the release rate and cumulative release percentage of the test drugs tetracycline hydrochloride (TCH) and levofloxacin hydrochloride (LH) between pure IPN hydrogels and cotton-fabric-supported IPN hydrogels (250, 500, and 1000 µm) at 25 °C (below the TT) and 37 °C (above the TT). Because of the compressive stress from the collapsed hydrogels, a higher release is observed in both hydrogels when the temperature is above TT. The cotton fabric induces a slower and less prominent drug release in IPN hydrogels. Thus, combining the obtained correlation between the transition and hydrogels layer thickness, the drug release in cotton-fabric-supported IPN hydrogels can be regulated by the layer thickness, which appears especially suitable for a controlled release in wound dressing applications.

Wearable Bracelet Monitoring the Solar Ultraviolet Radiation for Skin Health Based on Hybrid IPN Hydrogels.

The risk of extensive exposure of the human epidermis to solar ultraviolet radiation is significantly increased nowadays. It not only induces skin aging and solar erythema but also increases the possibility of skin cancer. Therefore, a simply prepared, highly sensitive, and optically readable device for monitoring the solar ultraviolet radiation is highly desired for the skin health management. Because of the photoinitiated polymerization triggered by graphene-carbon nitride (g-C3N4) under ultraviolet radiation, g-C3N4 is homogeneously distributed in the hybrid hydrogels containing N-isopropylacrymide (NIPAM), poly(ethylene glycol) methyl ether methacrylate (OEGMA300), and sodium alginate (SA). By further immersing the hybrid hydrogels into calcium chloride solution, hybrid alginate-Ca2+/P(NIPAM-co-OEGMA300)/g-C3N4 interpenetrating polymeric network (IPN) hydrogels are obtained. Due to the homogeneous distribution of g-C3N4 and the existence of thermoresponsive polymers, the hybrid IPN hydrogels present good adsorption capability and high degradation efficiency for methylene blue (MB) especially at high temperature under ultraviolet radiation. Based on this unique property, the bracelet monitoring skin health is prepared by simply immersing the hybrid IPN hydrogels into the MB solution and then wrapping it with PET foil. Because the immersion time for the top, middle, and bottom parts of the hybrid IPN hydrogels is gradually increased, their colors vary from light to dark blue. A longer time is required for the discoloration of the darker part under solar ultraviolet radiation. Thus, the bracelet can be used to conveniently monitor the dose of solar ultraviolet radiation by simply checking the discoloration in the bracelet under sunshine. Due to the facile preparation and low cost of the bracelet, it is a promising candidate for wearable devices for skin health management.

Linear Control of Moisture Permeability and Anti-adhesion of Bacteria in a Broad Temperature Region Realized by Cross-Linking Thermoresponsive Microgels onto Cotton Fabrics.

Linear control of moisture permeability and anti-adhesion of bacteria in a broad temperature region are realized by cross-linking thermoresponsive microgels onto cotton fabrics. The microgels are copolymerized by monomers di(ethylene glycol) methyl ether methacrylate (MEO2MA), (ethylene glycol) methyl ether methacrylate (OEGMA300), and ethylene glycol methacrylate (EGMA) with a molar ratio of 10:10:1. Transition temperatures of PMEO2MA and POEGMA300 are 25 and 60 °C, respectively. Due to the compression of already collapsed PMEO2MA to still swollen POEGMA300, the microgels present a linear shrinkage in a broad temperature region (20-70 °C). Additionally, the contact angle of the microgels stays below 60° even if the temperature is increased to 50 °C, illustrating the reserved surface hydrophilicity. The obtained microgels are cross-linked onto cotton fabrics by 1,2,3,4-butanetetracarboxylic (BTCA). The weight gain ratios (WGRs) are 15% and 30%. The moisture permeability shows an excellent linear increase between 20 and 50 °C when the WGR is 30%, which is attributed to the linear shrinkage of the cross-linked microgels upon heating. Because the moisture permeability is related to the fabric comfort, a linear control of comfort is obtained. In addition, the cross-linked cotton fabrics can realize 96.5% bacterial anti-adhesion at 30 °C as the surface remains hydrophilic. On the basis of these two unique properties, the realized cotton fabrics cross-linked with microgels are promising for application as smart textiles for wound addressing.

Bioactive gel self-assembled from phosphorylate biomimetic peptide: A potential scaffold for enhanced osteogenesis.

Bone morphogenetic protein-2 biomimetic peptide (BMPBP) is a potent osteoinductive cytokine and plays a critical role during bone regeneration. Efforts to prepare hydrogels with surface modification or physical absorption of bioactive molecules do not provide sufficient bioactivity to meet the requirements of clinical application. The goal of this study was to form a three-dimensional hydrogel comprised of BMP-2 core sequence oligopeptide, phosphoserine, a synthetic cell adhesion peptide (RGDS), and polyaspartic acid to synergistically promote osteogenesis. Experiments performed in vitro revealed that the peptide gel was conducive to adhesion and proliferation of rat marrow mesenchymal stem cells (rMSCs). In addition, RT-PCR analysis indicated that rMSCs allowed better expression of osteogenesis-related genes such as BMP-2, runt-related transcription factor 2 (RUNX2), alkaline phosphatase (ALP), osteocalcin (OCN), and osteopontin (OPN). Use of the rat cranial bone defects model with micro-CT 3D reconstruction showed that bone regeneration patterns occurred from one side edge toward the center of the area implanted with the prepared biomimetic peptide hydrogels, demonstrating significantly accelerated bone regeneration. This work will provide a basis to explore the further application potential of this bioactive scaffold.

Molecular cloning and characterization of wheat calreticulin (CRT) gene involved in drought-stressed responses.

Calreticulin (CRT) is a highly conserved and ubiquitously expressed Ca(2+)-binding protein in multicellular eukaryotes. CRT plays a crucial role in many cellular processes including Ca(2+) storage and release, protein synthesis, and molecular chaperone activity. To elucidate the function of CRTs in plant responses against drought, a main abiotic stress limiting cereal crop production worldwide, a full-length cDNA encoding calreticulin protein namely TaCRT was isolated from wheat (Triticum aestivum L.). The deduced amino acid sequence of TaCRT shares high homology with other plant CRTs. Phylogenetic analysis indicates that TaCRT cDNA clone encodes a wheat CRT3 isoform. Southern analysis suggests that the wheat genome contains three copies of TaCRT. Subcellular locations of TaCRT were the cytoplasm and nucleus, evidenced by transient expression of GFP fused with TaCRT in onion epidermal cells. Enhanced accumulation of TaCRT transcript was observed in wheat seedlings in response to PEG-induced drought stress. To investigate further whether TaCRT is involved in the drought-stress response, transgenic plants were constructed. Compared to the wild-type and GFP-expressing plants, TaCRT-overexpressing tobacco (Nicotiana benthamiana) plants grew better and exhibited less wilt under the drought stress. Moreover, TaCRT-overexpressing plants exhibited enhanced drought resistance to water deficit, as shown by their capacity to maintain higher WUE (water use efficiency), WRA (water retention ability), RWC (relative water content), and lower MDR (membrane damaging ratio) (P < or = 0.01) under water-stress conditions. In conclusion, a cDNA clone encoding wheat CRT was successfully isolated and the results suggest that TaCRT is involved in the plant response to drought stress, indicating a potential in the transgenic improvements of plant water-stress.

A Hydrogel-Based Localized Release of Colistin for Antimicrobial Treatment of Burn Wound Infection.

There is an urgent unmet medical need for new treatments for wound and burn infections caused by multidrug-resistant Gram-negative "superbugs," especially the problematic Pseudomonas aeruginosa. In this work, the incorporation of colistin, a potent lipopeptide into a self-healable hydrogel (via dynamic imine bond formation) following the chemical reaction between the amine groups present in glycol chitosan and an aldehyde-modified poly(ethylene glycol), is reported. The storage module (G') of the colistin-loaded hydrogel ranges from 1.3 to 5.3 kPa by varying the amount of the cross-linker and colistin loading providing different options for topical wound healing. The majority of the colistin is released from the hydrogel within 24 h and remains active as demonstrated by both antibacterial in vitro disk diffusion and time-kill assays. Moreover and pleasingly, the colistin-loaded hydrogel performs almost equally well as native colistin against both the colistin-sensitive and also colistin-resistant P. aeruginosa strain in the in vivo animal "burn" infection model despite exhibiting a slower killing profile in vitro. Based on this antibiotic performance along with the biodegradability of the product, it is believed the colistin-loaded hydrogel to be a potential localized wound-healing formulation to treat burn wounds against microbial infection.

A traceless reversible polymeric colistin prodrug to combat multidrug-resistant (MDR) gram-negative bacteria.

Colistin methanesulfonate (CMS) is the only prodrug of colistin available for clinical use for the treatment of infections caused by multidrug-resistant (MDR) Gram-negative bacteria. Owing to its slow and variable release, an alternative is urgently required to improve effectiveness. Herein we describe a PEGylated colistin prodrug whereby the PEG is attached via a cleavable linker (col-aaPEG) introducing an acetic acid terminated poly (ethylene glycol) methyl ether (aaPEG) onto the Thr residue of colistin. Due to the labile ester containing link, this prodrug is converted back into active colistin in vitro within 24h. Compared to CMS, it showed a similar or better antimicrobial performance against two MDR isolates of Pseudomonas aeruginosa and Acinetobacter baumannii through in vitro disk diffusion, broth dilution and time-kill studies. In a mouse infection model, col-aaPEG displayed acceptable bacterial killing against P. aeruginosa ATCC 27853 and no nephrotoxicity was found after systemic administration, suggesting it to be a potential alternative for CMS.

Polybrene: Observations on cochlear hair cell necrosis and minimal lentiviral transduction of cochlear hair cells.

Polybrene is widely used to enhance viral transduction; however, little is known about the utility thereof, in enhancing lentiviral transduction of cochlear cells. In the present study, we examined the cytotoxic effects of polybrene, and the further effects thereof, on lentiviral transduction of cochlear cells, especially sensory hair cells. Cochlear basilar membranes of newborn rats were cultured and treated with 0.1-10 µg/mL polybrene for 24h to explore the potential development of ototoxicity. PI staining and TUNEL detection were used to evaluate necrosis or apoptosis of hair cell. Various doses of lentivirus-GFP were added to cochlear organotypic cultures with safe concentrations of polybrene, incubated for 24h, and cultured (in the absence of the virus and polybrene) for a further 48 h. Transduction efficiencies were evaluated. The results showed that polybrene at 0.1 µg/mL was safe to cochlear cells, and 0.5-10 µg/mL concentration induced hair cell necrosis in a dose-dependent manner. However, supporting cells were not damaged. Lentiviral vectors transduced into cochlear cells and 0.1 µg/mL polybrene enhanced transduction efficiency. However, hair cells were hardly transduced with lentiviral vectors either alone or in the presence of 0.1 µg/mL polybrene. The use of polybrene to aid lentiviral transduction of cochlear hair cells requires further attention.

Evaluation of the anti-inflammatory properties of Dodonaea polyandra, a Kaanju traditional medicine.

ETHNOPHARMACOLOGICAL RELEVANCE: Extracts of the medicinal plant species Dodonaea polyandra were investigated as part of a collegial research partnership between Northern Kaanju traditional owners represented by Chuulangun Aboriginal Corporation (centred on the Wenlock and Pascoe Rivers, Cape York Peninsula, Queensland, Australia) and university-based researchers. D. polyandra, known as "Uncha" in Kaanju language, is used in Northern Kaanju Traditional Medicine for relief from pain associated with toothache and related ailments. The species has a restricted distribution in Cape York Peninsula and there has been no previous Western scientific investigation of its pharmacology or chemistry. AIM OF THE STUDY: The current study investigates the anti-inflammatory effects of several extracts from D. polyandra. MATERIALS AND METHODS: Phytochemical screening was conducted using TLC. Anti-inflammatory effects of leaf extracts were determined using an acute mouse ear oedema model induced by croton oil and 12-o-tetradecanoylphorbol-13-acetate (TPA) chemical irritants. RESULTS: Flavonoid and terpenoid secondary compounds were detected in leaf extracts of D. polyandra. Non-polar hexane and methylene chloride/methanol extracts showed potent inhibition of inflammation in TPA-induced mouse ear oedema by 72.12 and 79.81%, respectively, after 24 h at 0.4 mg/ear. CONCLUSION: In a mouse model of acute inflammation, this study revealed that leaf extracts of D. polyandra possess significant anti-inflammatory potential. These results contribute to a Western scientific understanding of the ethnopharmacological use of the plant in Northern Kaanju Medicine for reducing tooth-related pain.

[A "silicone suture" technique aided to scalp reduction for the treatment of scarring alopecia].

OBJECTIVE: To evaluate a "silicone suture" technique for enhancing the effect of scalp reduction. METHODS: Under the local anesthesia, when an incision was made in the midline of the lesion, the dissection was carried out underlying the sub-galea on both sides of the lesion, as far as the width of the lesion. A 3 mm silicone suture in diameter was placed in the galea beyond the lesion. After the first suture bite was anchored in the tissue at one end, the suture device was continued across the midline in such a way as a running, buried, horizontal mattress suture and it was brought out to the skin surface through the deep tissue at the another end of the lesion with a locker. The extra-tissue of the lesion was then excised and the wound was directly closed in layers. After one week of the operation, the silicone suture was gradually tightened in 2-3 times a week for about 3-5 weeks, until both sides of the lesion were approximately closed. The device was there after removed and the wound was directly closed in layers after the scar was excised. RESULTS: Between October of 1999 and March of 2006, 12 scarring-scalp patients, 7 males and 5 females, were treated by using the silicone suture device without complications. The excised defects were 5-10.5 cm in width. The stretching period was 26.4 days in mean. With the following-ups over 3 months, no hypertrophic scar and widening scar cases appeared. CONCLUSIONS: The silicone suture as an alternative device for tissue extension could be a safe, simple, effective and economical device. It could significantly enhance the efficiency of scalp reduction.