Comparison of the Antimicrobial and Hemolytic Activities of Various Forms of Silver (Ions, Nanoparticles, Bioconjugates) Stabilized in a Zeolite Matrix.

A quantitative and qualitative comparison of the antimicrobial and hemolytic activities of silver in various states, in the form of ions, nanoparticles, and bioconjugates with the antimicrobial protein lysozyme stabilized in an inert zeolite matrix, has been carried out. A synthetic zeolite with a ß structure was chosen as a zeolite matrix. Using the ion-exchange method, the method of chemical reduction, and treating the matrix with a silver hydrosol with specified characteristics, samples of zeolites with the same silver content in various forms (Ag+, Ag° - Ag°/Lyz) in the amounts of 0.8 and 5 wt % have been synthesized. The samples obtained were studied by a complex of physicochemical research methods: X-ray diffraction, UV absorption spectroscopy, low-temperature nitrogen adsorption, electron microscopy, and atomic absorption. Antimicrobial activity was assessed against antibiotic-resistant Gram-negative microbe (e.g., Escherichia coli ML-35, Pseudomonas aeruginosa 522/17 MDR, Klebsiella pneumoniae ESBL 344) and Gram-positive microbe (e.g., Staphylococcus aureus 1399/17). The hemolytic activity in relation to human erythrocytes was estimated. The results obtained showed significant antimicrobial activity with a simultaneously high hemolytic activity of ionic silver. Silver nanoparticles have a lower level of antimicrobial activity and toxicity. Bioconjugates of silver nanoparticles and lysozyme showed an optimal combination of antimicrobial properties and lack of hemolytic activity.

Aluminosilicate Nanosponges: Synthesis, Properties, and Application Prospects.

A simple one-step method is presented for fabricating inorganic nanosponges with a kaolinite [Al2Si2O5(OH)4] structure. The nanosponges were synthesized by the hydrothermal treatment of aluminosilicate gels in an acidic medium (pH = 2.6) at 220 °C without using organic cross-linking agents, such as cyclodextrin or polymers. The formation of the nanosponge morphology was confirmed by scanning electron microscopy, and the assignment of the synthesized aluminosilicates to the kaolinite group was confirmed by X-ray diffraction and infrared spectroscopy. The effect of the synthesis conditions, in particular, the nature (HCl, HF, NaOH, and H2O) and pH of the reaction medium (2.6, 7, and 12), as well as the duration of the synthesis (3, 6, and 12 days), on the morphology of aluminosilicates of the kaolinite group was studied. The sorption capacity of aluminosilicate nanosponges with respect to cationic (e.g., methylene blue) and anionic (e.g., azorubine) dyes in aqueous solutions was studied. The pH sensitivity of the surface ζ potential of the synthesized nanosponges was demonstrated. The dependence of the hemolytic activity (the ability to destroy erythrocytes) of aluminosilicate nanoparticles on the particle morphology (platy, spherical, and nanosponge) has been identified for the first time. Aluminosilicate nanosponges were not found to exhibit hemolytic activity. The prospects of using aluminosilicate nanosponges to prepare innovative functional materials for ecology and medicine applications, in particular, as matrices for drug delivery systems, were identified.

Comprehensive peripheral blood immunoprofiling reveals five immunotypes with immunotherapy response characteristics in patients with cancer.

The lack of comprehensive diagnostics and consensus analytical models for evaluating the status of a patient's immune system has hindered a wider adoption of immunoprofiling for treatment monitoring and response prediction in cancer patients. To address this unmet need, we developed an immunoprofiling platform that uses multiparameter flow cytometry to characterize immune cell heterogeneity in the peripheral blood of healthy donors and patients with advanced cancers. Using unsupervised clustering, we identified five immunotypes with unique distributions of different cell types and gene expression profiles. An independent analysis of 17,800 open-source transcriptomes with the same approach corroborated these findings. Continuous immunotype-based signature scores were developed to correlate systemic immunity with patient responses to different cancer treatments, including immunotherapy, prognostically and predictively. Our approach and findings illustrate the potential utility of a simple blood test as a flexible tool for stratifying cancer patients into therapy response groups based on systemic immunoprofiling.

Effect of selumetinib on the growth of anastrozole-resistant tumors.

Despite significant improvement in the treatment outcome of hormone responsive postmenopausal breast cancer, some patients eventually acquire resistance to aromatase inhibitors (AIs). Using our MCF-7Ca xenograft model, we observed that although AIs such as anastrozole initially inhibit tumor growth effectively, tumors eventually began to grow. Our previous data show that anastrozole-resistant tumors upregulate growth factor receptor pathways as they adapt to grow in the low estrogen environment. Therefore, in the current study, we investigated the effect of inhibiting the growth factor receptor pathways with a MEK-1/2 inhibitor selumetinib (AZD6244, ARRY-142866). We treated the mice with anastrozole-resistant tumors with selumetinib alone or in combination with anastrozole. MCF-7Ca cells were inoculated sc into ovariectomized athymic nude mice supplemented throughout the experiment with androstenedione (100 µg/day), the substrate for aromatase conversion to estrogen. Once the tumors reached a measurable size (~300 mm(3)), the mice were treated with anastrozole (200 µg/day), supplemented with androstenedione (Δ(4)A). The tumors in the anastrozole group doubled in volume after 6 weeks, at which time the animals were regrouped to receive the following treatments: (i) anastrozole, (ii) anastrozole withdrawal (Δ(4)A alone), (iii) selumetinib (25 mg/kg/d, bid, po), and (iv) selumetinib + anastrozole, (n = 10 mice/group). The treatments were given for 6 weeks (till week 12) and then the mice were euthanized, the tumors were collected and analyzed. The tumors of mice treated with selumetinib + anastrozole had significantly lower growth rates than those treated with single agents (p = 0.008). Western blot analysis of the tumors showed that treatment with anastrozole resulted in upregulation of proteins in the growth factor receptor cascade such as p-mTOR, pAkt, pMEK, and pMAPK. This was accompanied by downregulation of ERα protein, consistent with previous findings. The treatment of mice with selumetinib resulted in downregulation of activated MAPK, along with p-mTOR, which likely resulted in upregulation of ERα. Our results suggest that inhibition of the growth factor receptor pathway with selumetinib can reverse anastrozole resistance.

Hemolytic Activity and Cytotoxicity of Synthetic Nanoclays with Montmorillonite Structure for Medical Applications.

The factors influencing the appearance of toxicity in samples of synthetic montmorillonite with a systematically changing chemical composition Nax(Al, Mg)2-3Si4O10(OH)2 nH2O, which are potentially important for their use in medicine as drug carriers, targeted drug delivery systems, entero- and hemosorbents have been studied. Samples synthesized under hydrothermal conditions had the morphology of nanolayers self-organized into the nanosponge structures. The effect of the aluminum content, particle sizes, porosity, and ζ-potential of the samples on their toxicity was studied. The cytotoxic effect of the samples on eukaryotic cells Ea. hy 926 was determined using the MTT assay. The hemolytic activity of the samples in the wide concentration range in relation to human erythrocytes was also estimated. It has been established that the toxicity of aluminosilicate nanoparticles can be significantly reduced by correctly selecting their synthesis conditions and chemical composition, which opens up the opportunities for their use in medicine.

Particles Morphology Impact on Cytotoxicity, Hemolytic Activity and Sorption Properties of Porous Aluminosilicates of Kaolinite Group.

A comparative study of the properties of aluminosilicates of the kaolinite (Al2Si2O5(OH)4∙nH2O) group with different particles morphology has been carried out. Under conditions of directed hydrothermal synthesis, kaolinite nanoparticles with spherical, sponge, and platy morphologies were obtained. Raw nanotubular halloysite was used as particles with tubular morphology. The samples were studied by X-ray diffraction, SEM, solid-state NMR, low-temperature nitrogen adsorption, and the dependence of the zeta potential of the samples on the pH of the medium was defined. The sorption capacity with respect to cationic dye methylene blue in aqueous solutions was studied. It was found that sorption capacity depends on particles morphology and decreases in the series spheres-sponges-tubes-plates. The Langmuir, Freundlich, and Temkin models describe experimental methylene blue adsorption isotherms on aluminosilicates of the kaolinite subgroup with different particles morphology. To process the kinetic data, pseudo-first order and pseudo-second order were used. For the first time, studies of the dependence of hemolytic activity and cytotoxicity of aluminosilicate nanoparticles on their morphology were carried out. It was found that aluminosilicate nanosponges and spherical particles are not toxic to human erythrocytes and do not cause their destruction at sample concentrations from 0.1 to 1 mg/g. Based on the results of the MTT test, the concentration value that causes 50% inhibition of cell population growth (IC50, mg/mL) was calculated. For nanotubes, this value turned out to be the smallest-0.33 mg/mL. For samples with platy, spherical and nanosponge morphology, the IC50 values were 1.55, 2.68, and 4.69 mg/mL, respectively.

Pharmacological evaluation of Potentilla alba L. in mice: adaptogenic and central nervous system effects.

CONTEXT: Potentilla alba L. (Rosaceae) rhizomes have anti-inflammatory, antioxidant, and adaptogenic effects and are used for the treatment of diarrhea and intestinal colic. However, the data concerning the adaptogenic and central nervous system activities of P. alba are fragmentary. OBJECTIVES: To determine the effect of oral administration of dried P. alba extract on the swimming endurance, light/dark exploration, and open-field tests for mice. MATERIALS AND METHODS: The mice were orally administered Rhodiola rosea extract (RR group); dry extract of P. alba at doses of 12, 36, or 72 mg/kg (groups: PA12, PA36, and PA72); or distilled water (control group) for 7 consecutive days. RESULTS: The swimming times of the RR, PA36, and PA72 groups were significantly longer than those of the control group. The administration of P. alba significantly increased the light time, latency time, and the number of rearings in a dose-dependent manner. In the open-field test, the P. alba extract at a dose of 12 mg/kg produced a significant increase in the frequency of head dipping and the number of squares crossed and a significant decrease in grooming compared with the control treatment. CONCLUSION: The current findings demonstrate that P. alba extracts significantly increased swimming endurance time and have anxiolytic-like action with a predominant locomotor component.

Silver Nanoparticles Functionalized With Antimicrobial Polypeptides: Benefits and Possible Pitfalls of a Novel Anti-infective Tool.

Silver nanoparticles (AgNPs) and antimicrobial peptides or proteins (AMPs/APs) are both considered as promising platforms for the development of novel therapeutic agents effective against the growing number of drug-resistant pathogens. The observed synergy of their antibacterial activity suggested the prospect of introducing antimicrobial peptides or small antimicrobial proteins into the gelatinized coating of AgNPs. Conjugates with protegrin-1, indolicidin, protamine, histones, and lysozyme were comparatively tested for their antibacterial properties and compared with unconjugated nanoparticles and antimicrobial polypeptides alone. Their toxic effects were similarly tested against both normal eukaryotic cells (human erythrocytes, peripheral blood mononuclear cells, neutrophils, and dermal fibroblasts) and tumor cells (human erythromyeloid leukemia K562 and human histiocytic lymphoma U937 cell lines). The AMPs/APs retained their ability to enhance the antibacterial activity of AgNPs against both Gram-positive and Gram-negative bacteria, including drug-resistant strains, when conjugated to the AgNP surface. The small, membranolytic protegrin-1 was the most efficient, suggesting that a short, rigid structure is not a limiting factor despite the constraints imposed by binding to the nanoparticle. Some of the conjugated AMPs/APs clearly affected the ability of nanoparticle to permeabilize the outer membrane of Escherichia coli, but none of the conjugated AgNPs acquired the capacity to permeabilize its cytoplasmic membrane, regardless of the membranolytic potency of the bound polypeptide. Low hemolytic activity was also found for all AgNP-AMP/AP conjugates, regardless of the hemolytic activity of the free polypeptides, making conjugation a promising strategy not only to enhance their antimicrobial potential but also to effectively reduce the toxicity of membranolytic AMPs. The observation that metabolic processes and O2 consumption in bacteria were efficiently inhibited by all forms of AgNPs is the most likely explanation for their rapid and bactericidal action. AMP-dependent properties in the activity pattern of various conjugates toward eukaryotic cells suggest that immunomodulatory, wound-healing, and other effects of the polypeptides are at least partially transferred to the nanoparticles, so that functionalization of AgNPs may have effects beyond just modulation of direct antibacterial activity. In addition, some conjugated nanoparticles are selectively toxic to tumor cells. However, caution is required as not all modulatory effects are necessarily beneficial to normal host cells.

Application of Antimicrobial Peptides of the Innate Immune System in Combination With Conventional Antibiotics-A Novel Way to Combat Antibiotic Resistance?

Rapidly growing resistance of pathogenic bacteria to conventional antibiotics leads to inefficiency of traditional approaches of countering infections and determines the urgent need for a search of fundamentally new anti-infective drugs. Antimicrobial peptides (AMPs) of the innate immune system are promising candidates for a role of such novel antibiotics. However, some cytotoxicity of AMPs toward host cells limits their active implementation in medicine and forces attempts to design numerous structural analogs of the peptides with optimized properties. An alternative route for the successful AMPs introduction may be their usage in combination with conventional antibiotics. Synergistic antibacterial effects have been reported for a number of such combinations, however, the molecular mechanisms of the synergy remain poorly understood and little is known whether AMPs cytotoxicy for the host cells increases upon their application with antibiotics. Our study is directed to examination of a combined action of natural AMPs with different structure and mode of action (porcine protegrin 1, caprine bactenecin ChBac3.4, human alpha- and beta-defensins (HNP-1, HNP-4, hBD-2, hBD-3), human cathelicidin LL-37), and egg white lysozyme with varied antibiotic agents (gentamicin, ofloxacin, oxacillin, rifampicin, polymyxin B, silver nanoparticles) toward selected bacteria, including drug-sensitive and drug-resistant strains, as well as toward some mammalian cells (human erythrocytes, PBMC, neutrophils, murine peritoneal macrophages and Ehrlich ascites carcinoma cells). Using "checkerboard titrations" for fractional inhibitory concentration indexes evaluation, it was found that synergy in antibacterial action mainly occurs between highly membrane-active AMPs (e.g., protegrin 1, hBD-3) and antibiotics with intracellular targets (e.g., gentamicin, rifampcin), suggesting bioavailability increase as the main model of such interaction. In some combinations modulation of dynamics of AMP-bacterial membrane interaction in presence of the antibiotic was also shown. Cytotoxic effects of the same combinations toward normal eukaryotic cells were rarely synergistic. The obtained data approve that combined application of antimicrobial peptides with antibiotics or other antimicrobials is a promising strategy for further development of new approach for combating antibiotic-resistant bacteria by usage of AMP-based therapeutics. Revealing the conventional antibiotics that increase the activity of human endogenous AMPs against particular pathogens is also important for cure strategies elaboration.

Mechanisms of Melanophore Induction in Amphibian Development: (pigment cells/ap /ap mutant/induction/mechanism).

Induction of melanophores was examined by the sandwich method of explantation with embryonic tissues of Xenopus laevis+/+ and the white mutant, aP /aP . Interspecific combinations of tissues of Triturus taeniatus and Xenopus borealis were also used. The ectoderm used as the reacting system was taken from embriyos at various stages and combined with various tissues known to be melanogenic inductors. The following results were obtained: 1) The sources of melanophore induction in both +/+ and ap /ap studied by sandwich explantation were the same in both retinal pigmented epithelium and dermal melanophores: 2) Melanophores were induced in epidermal material from embryos at stages from the early gastrula to the late tail bud stage: 3) The presence of melanoblasts together with other ectomesenchymal cells in the neural crest is not sine qua non for their determination and differentiation: 4) On isolation of reacting material from the late gastrula, melanophores appeared in all cases. This shows that two hours contact between inductor tissues and the ectoderm is necessary and sufficient for melanophore induction: 5) Melanophore induction is not species-specific, but occurred in Xenopus ectoderm under the action of endomesoderm of Tr. taeniatus or X. borealis, and vice versa. The shapes and structures of melanophores induced were typical for the species from which the ectoderm was taken: 6) Melanogenic activity in the late gastrula stage has a gradient of distribution with a maximum in the prechordal plate: 7) In the mutant only the primary source of melanogenic inductors, the prechordal plate (PrP1), was active in stages both before and after its invagination: 8) Despite the fact that skin melanophores and retinal melanocytes have different genesis in development, all the present data suggest the identity of the mechanisms of melanin synthesizing machinery in the two.

Isolation of a Factor Mediating Melanogenic Induction in Pigment Cells of Xenopus Laevis: (pigment cells/ap /ap mutant/melanocyte differentiation/embryonic induction).

An activity has been identified in +/+Xenopus laevis embryonic extract which stimulates intensive and stable melanoprotein synthesis in retinal pigmented epithelium and dermal melanophores of albino periodical mutants, ap /ap . Experiments involved four steps: 1) preparation of extract from +/+ embryos at stages NF 18-21 when melanogenesis occurs most extensively; 2) gel-filtration of the extract; 3) microinjection of the fractionated materials into ap /ap ; and 4) identification of the nature of active substances. The activity is heat-labile and is destroyed by treatment with pronase E. We call this material melanogenic factor (MGF) and suggest that it is responsible for initiating melanogenic activity in melanin-synthesizing cells.

Heterologous envelope immunogens contribute to AIDS vaccine protection in rhesus monkeys.

Because a strategy to elicit broadly neutralizing anti-human immunodeficiency virus type 1 (HIV-1) antibodies has not yet been found, the role of an Env immunogen in HIV-1 vaccine candidates remains undefined. We sought to determine whether an HIV-1 Env immunogen genetically disparate from the Env of the challenge virus can contribute to protective immunity. We vaccinated Indian-origin rhesus monkeys with Gag-Pol-Nef immunogens, alone or in combination with Env immunogens that were either matched or mismatched with the challenge virus. These animals were then challenged with a pathogenic simian-human immunodeficiency virus. The vaccine regimen included a plasmid DNA prime and replication-defective adenoviral vector boost. Vaccine regimens that included the matched or mismatched Env immunogens conferred better protection against CD4(+) T-lymphocyte loss than that seen with comparable regimens that did not include Env immunogens. This increment in protective immunity was associated with anamnestic Env-specific cellular immunity that developed in the early days following viral challenge. These data suggest that T-lymphocyte immunity to Env can broaden the protective cellular immune response to HIV despite significant sequence diversity of the strains of the Env immunogens and can contribute to immune protection in this AIDS vaccine model.