A multifunctional cascade enzyme system for enhanced starvation/chemodynamic combination therapy against hypoxic tumors

Starvation therapy has shown promise as a cancer treatment, but its efficacy is often limited when used alone. In this work, a multifunctional nanoscale cascade enzyme system, named CaCO3@MnO2-NH2@GOx@PVP (CMGP), was fabricated for enhanced starvation/chemodynamic combination cancer therapy. CMGP is composed of CaCO3 nanoparticles wrapped in a MnO2 shell, with glucose oxidase (GOx) adsorbed and modified with polyvinylpyrrolidone (PVP). MnO2 decomposes H2O2 in cancer cells into O2, which enhances the efficiency of GOx-mediated starvation therapy. CaCO3 can be decomposed in the acidic cancer cell environment, causing Ca2+ overload in cancer cells and inhibiting mitochondrial metabolism. This synergizes with GOx to achieve more efficient starvation therapy. Additionally, the H2O2 and gluconic acid produced during glucose consumption by GOx are utilized by MnO2 with catalase-like activity to enhance O2 production and Mn2+ release. This process accelerates glucose consumption, reactive oxygen species (ROS) generation, and CaCO3 decomposition, promoting the Ca2+ release. CMGP can alleviate tumor hypoxia by cycling the enzymatic cascade reaction, which increases enzyme activity and combines with Ca2+ overload to achieve enhanced combined starvation/chemodynamic therapy. In vitro and in vivo studies demonstrate that CMGP has effective anticancer abilities and good biosafety. It represents a new strategy with great potential for combined cancer therapy.

Polyvinylpyrrolidone-coated copper nanoparticles dose-dependently conferred tolerance to wheat under salinity and/or drought stress by improving photochemical activity and antioxidant system

Copper (Cu) is one of the essential micronutrients for plants and has been used extensively in agricultural applications from the past to the present. However, excess copper causes toxic effects such as inhibiting photosynthesis, and disrupting biochemical processes in plants. Nanotechnology applications have offered a critical method for minimizing adverse effects and improving the effectiveness of copper nanoparticles. For this purpose, this study investigated the physiological and biochemical effects of polyvinylpyrrolidone (PVP)-coated Cu nanoparticles (PVP-Cu NP, N1, 100 mg L-1; N2, 400 mg L-1) in Triticum aestivum under alone or combined with salt (S, 150 mM NaCl) and/or drought (D, %10 PEG-6000) stress. Salinity and water deprivation caused 51% and 22% growth retardation in wheat seedlings. The combined stress condition (S + D) resulted in an approximately 3-fold reduction in the osmotic potential of the leaves. PVP-Cu NP treatments to plants under stress, especially N1 dose, were effective in restoring growth rate and regulating water relations. All stress treatments limited gas exchange in stomata and suppressed the maximal quantum yield of PSII (Fv/Fm). More than 50% improvement was observed in stomatal permeability and carbon assimilation rate under S + N1 and S + N2 applications. Examination of OJIP transient parameters revealed that N1 treatments protected photochemical reactions by reducing the dissipated energy flux (DIo/RC) in drought and S + D conditions. Exposure to S and/or D stress caused high hydrogen peroxide (H2O2) accumulation and lipid peroxidation in wheat leaves. The results indicated that S + N1 and S + N2 treatments reduced oxidative damage by stimulating the activities of antioxidant enzymes superoxide dismutase (SOD), peroxidase (POX), and ascorbate peroxidase (APX). Although similar effects were observed at D and S + D conditions with 100 mg L-1 PVP-Cu NP treatments (N1), the curative effect of the N2 dose was not observed. In D + N1 and S + D + N1 groups, AsA regeneration and GSH redox status were maintained by triggering APX, GR, and other enzyme activities belonging to the AsA-GSH cycle. In these groups, N2 treatment did not contribute to the availability of enzymatic and non-enzymatic antioxidants. As a result, this study revealed that N1 dose PVP-Cu NP application was successful in providing stress tolerance and limiting copper-induced adverse effects under all stress conditions.

Curcumin-PVP improves the in vitro efficacy of ivermectin against resistant and susceptible Haemonchus contortus

Ivermectin (IVM) resistance in parasitic nematodes such as Haemonchus contortus has spurred a search for substances that help to recover its efficacy. One potential agent is the natural product curcumin (CUR). In this study, CUR was combined with polyvinylpyrrolidone (PVP) (CUR/PVP) to improve its solubility and biological applicability. This study determined the effect of CUR preincubation on the effective concentration 50% (EC50) of IVM in three H. contortus isolates with different susceptibilities to IVM. The IVM EC50 was determined for three H. contortus isolates with different IVM susceptibilities using the larval migration inhibition (LMI) test. The three isolates were (i) PARAISO (IVM resistant), (ii) FMVZ-UADY (IVM susceptible), and (iii) CENID-SAI INIFAP (reference IVM susceptible). The L3 of each isolate were preincubated for 3 h with one of three concentrations of CUR (μg curcumin/mL): CONC-1 (3.67), CONC-2 (5.67), or CONC-3 (8.48). Corresponding controls were performed without CUR. The EC50 of IVM was determined for each isolate after they were exposed to the different CUR concentrations. The EC50 of IVM differed between the isolates PARAISO > FMVZ-UADY > CENID-SAI INIFAP (P < 0.05). The CUR preincubation at CONC-1 did not decrease the EC50 of IVM for any of the three isolates, suggesting a hormetic effect. By contrast, CUR preincubation at CONC-2 or CONC-3 decreased the IVM EC50 for the PARAISO isolate (P < 0.05) compared with the reference isolate and reduced the EC50 of IVM for the FMVZ-UADY and CENID-SAI INIFAP isolates below the EC50 for the CENID-SAI INIFAP isolate without CUR preincubation. In conclusion, preincubation of H. contortus L3 with CUR reduced the EC50 of IVM for field isolates classified as resistant and susceptible to IVM. The CUR preincubation reduced the IVM resistance factor in the different isolates tested.

Efficient Strategies to Use β-Cationic Porphyrin-Imidazolium Derivatives in the Photoinactivation of Methicillin-Resistant Staphylococcus aureus

Bacterial resistance to antibiotics is a critical global health issue and the development of alternatives to conventional antibiotics is of the upmost relevance. Antimicrobial photodynamic therapy (aPDT) is considered a promising and innovative approach for the photoinactivation of microorganisms, particularly in cases where traditional antibiotics may be less effective due to resistance or other limitations. In this study, two β-modified monocharged porphyrin-imidazolium derivatives were efficiently incorporated into polyvinylpyrrolidone (PVP) formulations and supported into graphitic carbon nitride materials. Both porphyrin-imidazolium derivatives displayed remarkable photostability and the ability to generate cytotoxic singlet oxygen. These properties, which have an important impact on achieving an efficient photodynamic effect, were not compromised after incorporation/immobilization. The prepared PVP-porphyrin formulations and the graphitic carbon nitride-based materials displayed excellent performance as photosensitizers to photoinactivate methicillin-resistant Staphylococcus aureus (MRSA) (99.9999% of bacteria) throughout the antimicrobial photodynamic therapy. In each matrix, the most rapid action against S. aureus was observed when using PS 2. The PVP-2 formulation needed 10 min of exposure to white light at 5.0 µm, while the graphitic carbon nitride hybrid GCNM-2 required 20 min at 25.0 µm to achieve a similar level of response. These findings suggest the potential of graphitic carbon nitride-porphyrinic hybrids to be used in the environmental or clinical fields, avoiding the use of organic solvents, and might allow for their recovery after treatment, improving their applicability for bacteria photoinactivation.

Zn2+ @Polyvinylpyrrolidone and Urushiol Preparation of Nanofibrous Membranes and Their Synergistic Effect

In this study, lacquer is gathered from a lacquer tree and rotary evaporation is used to remove impurities to obtain urushiol. Next, 10 mL of anhydrous ethanol serves as the solvent for blending polyvinylpyrrolidone (PVP) at a specified content (0.7 g and 0.2-0.7 g urushiol) to form an electrospinning solution. Electrospinning is carried out with a voltage of 18 kV to prepare PVP/urushiol nanofibrous membranes. At a ratio of 7/4, the PVP/urushiol nanofibrous membranes are not eroded in 98% sulfuric acid and these membranes also demonstrate a 50-60% antibacterial effect against Staphylococcus aureus and Escherichia coli. Moreover, the antibacterial effect can be boosted to 98% with the incorporation of zinc ions. The results indicate that anhydrous ethanol can remove the sensitization of urushiol from PVP/urushiol membranes. Furthermore, animal test results indicate that when rats are in contact with PVP/urushiol anhydrous ethanol for 48 h, their skins are free from dark brown skin allergy. The presence of PVP eliminates the sensitization of urushiol, and the nanofibrous membranes demonstrate low toxicity. Hence, urushiol is the only natural material that enables PVP to withstand 98% sulfuric acid as well as acquire hydrolyzability, thereby qualify PVP as a medical material.

Antimicrobial potential and rhodamine B dye degradation using graphitic carbon nitride and polyvinylpyrrolidone doped bismuth tungstate supported with in silico molecular docking studies

The environmental-friendly hydrothermal method has been carried out to synthesize Bi2WO6 and g-C3N4/PVP doped Bi2WO6 nanorods (NRs) by incorporating different concentrations of graphitic carbon nitride (g-C3N4) as well as a specified quantity of polyvinylpyrrolidone (PVP). Bi2WO6 doped with g-C3N4 provides structural and chemical stability, reduces charge carriers, degrades dyes, and, owing to lower bandgap energy, is effective for antibacterial, catalytic activity, and molecular docking analysis. The purpose of this research is the treatment of polluted water and to investigate the bactericidal behavior of a ternary system. The catalytic degradation was performed to remove the harmful rhodamine B (RhB) dye using NaBH4 in conjunction with prepared NRs. The specimen compound demonstrated antibacterial activity against Escherichia coli (E. coli) at both high and low concentrations. Higher doped specimens of g-C3N4/PVP-doped Bi2WO6 exhibited a significant improvement in efficient bactericidal potential against E. coli (4.55 mm inhibition zone). In silico experiments were carried out on enoyl-[acylcarrier-protein] reductase (FabI) and β-lactamase enzyme for E. coli to assess the potential of Bi2WO6, PVP doped Bi2WO6, and g-C3N4/PVP-doped Bi2WO6 NRs as their inhibitors and to justify their possible mechanism of action.

Ultrasmall zirconium carbide nanodots for synergistic photothermal-radiotherapy of glioma

Glioma is characterized by highly invasive, progressive, and lethal features. In addition, conventional treatments have been poorly effective in treating glioma. To overcome this challenge, synergistic therapies combining radiotherapy (RT) with photothermal therapy (PTT) have been proposed and extensively explored as a highly feasible cancer treatment strategy. Herein, ultrasmall zirconium carbide (ZrC) nanodots were successfully synthesized with high near-infrared absorption and strong photon attenuation for synergistic PTT-RT of glioma. ZrC-PVP nanodots with an average size of approximately 4.36 nm were prepared by the liquid exfoliation method and modified with the surfactant polyvinylpyrrolidone (PVP), with a satisfactory absorption and photothermal conversion efficiency (53.4%) in the near-infrared region. Furthermore, ZrC-PVP nanodots can also act as radiosensitizers to kill residual tumor cells after mild PTT due to their excellent photon attenuating ability, thus achieving a significant synergistic therapeutic effect by combining RT and PTT. Most importantly, both in vitro and in vivo experimental results further validate the high biosafety of ZrC-PVP NDs at the injected dose. This work systematically evaluates the feasibility of ZrC-PVP NDs for glioma treatment and provides evidence of the application of zirconium-based nanomaterials in photothermal radiotherapy.

Silk protein/polyvinylpyrrolidone nanofiber membranes loaded with puerarin accelerate wound healing in mice by reducing the inflammatory response

In modern clinical applications, wound healing remains a considerable challenge. Excessive inflammatory response is associated with delayed wound healing. In this study, we prepared composite nanofibrous membranes by mixing the Chinese herbal extract puerarin (PUE) with natural silk protein (SF) and synthetic polymer polyvinylpyrrolidone (PVP) using electrostatic spinning technique, and conducted a series of studies on the structural and biological properties of the fibrous membranes. The results showed that the loading of PUE increased the diameter, porosity and hydrophilicity of nanofibers, which were more favorable for cell adhesion and proliferation. ABTS radical scavenging assay also showed that the loading of PUE enhanced the antioxidant properties of the fibrous membranes. In addition, SF/PVP/PUE nanofibers are non-toxic and can be used as wound dressings. In vitro experiments showed that SF/PVP/PUE nanofibers could effectively alleviate lipopolysaccharide (LPS)-induced inflammation in Immortalized human keratinocytes (HaCaT) cells and down-regulate pro-inflammatory cytokine expression in cells. In vivo studies further showed that the SF/PVP/PUE nanofibers could effectively accelerate wound repair. The mechanism is that SF/PVP/PUE nanofibers can inhibit the activation and transduction of toll-like receptor 4/myeloid differentiation factor88/nuclear factor kappa B (TLR4/MyD88/NF-κB) and phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) signaling pathways, thereby reducing the inflammatory response and achieving wound healing.

[Study on the Effect of Polystyrene-Polyvinylpyrrolidone Electrospun Fibre in Inhibiting the Adhesion of Porphyromonas gingivalis]

OBJECTIVE

To explore the effect of polystyrene (PS) and PS-polyvinylpyrrolidone (PVP) electrospun materials on the adhesion ability of Porphyromonas gingivalis( P. gingivalis), a common periodontal pathogen.

METHODS

PS and PS-PVP electrospun materials were prepared with stainless steel needles in high-voltage electric field. The growth and adhesion of P. gingivalis on the surface of different materials were observed with scanning electron microscope (SEM). The changes in the amount of P. gingivalis biofilm formed on the surface of different materials were measured according to viable colony forming units (CFU). The effect of surface charge of the different materials on the adhesion ability of P. gingivalis was determined through changing the charge properties on the surface of the electrospun materials.

RESULTS

SEM images showed that both PS and PS-PVP can be used to form electrospun fibers with a diameter of 0.2 μm. SEM images and CFU counts of the biofilm at 24 h and 48 h showed that there was a smaller amount of P. gingivalis biofilm on the surface of the two materials ( P<0.05). After treatment with tetrabutylammonium bromide (TBAB), the surface charge of the PS-PVP electrospun material changed from being negatively charged to being positively charged, and the amount of bacterial adhesion on the surface increased significantly in comparison to that of untreated PS and PS-PVP materials ( P<0.05).

CONCLUSION

PS and PS-PVP electrospun materials can be used to reduce the adhesion ability of P. gingivalis on the surface of different materials, and this ability may be related to the surface charge properties of the materials.

Protective Effects of Polyvinylpyrrolidone-Wrapped Fullerene Against Nitric Oxide/Peroxynitrite-Induced Cellular Injury in Human Skin Keratinocytes

Excess ultraviolet (UV) exposure accelerates skin inflammation, melanogenesis, wrinkle formation, photoaging, and carcinogenesis through oxidative stress and deoxyribonucleic acid damage. These deleterious effects to skin are closely associated with UV-induced reactive oxygen species (ROS) and reactive nitrogen species (RNS) produced via nitric oxide (NO^·) generation. RNS are known to be responsible for various skin disorders, such as erythema, melanin production, reduced barrier function, and psoriasis. These skin disorders are major cosmetic problems; RNS control, in addition to ROS control, is important for maintaining healthy skin. In the present study, we investigated the cytoprotective effects of polyvinylpyrrolidone-entrapped fullerene (C₆₀/PVP), a water-soluble ROS scavenger, against nitric oxide (NO^·) and peroxynitrite (ONOO^-)-induced human keratinocyte injuries. Protective effects of C₆₀/PVP on NO^·/ONOO^--induced cellular damage and intracellular ONOO^- generation were evaluated using a NO^· donor S-nitroso-N-acetylpenicillamine (SNAP) in human skin epidermal HaCaT keratinocytes. Furthermore, the suppressive effect of C₆₀/PVP on UVB-induced generation of intracellular ONOO^- levels was also investigated. C₆₀/PVP exerted suppressive effects on intracellular increases in NO^·-induced ONOO^- generation and subsequent cellular damage. Additionally, C₆₀/PVP significantly decreased the UVB-induced generation of intracellular ONOO^- levels. These findings suggest that C₆₀/PVP could be useful as a cosmetics ingredient for prevention of skin injuries and/or dysfunction from NO^·/ONOO^--induced effects in human skin keratinocytes.

Fucoxanthin@Polyvinylpyrrolidone Nanoparticles Promoted Oxidative Stress-Induced Cell Death in Caco-2 Human Colon Cancer Cells

Fucoxanthin (FX), a natural carotenoid found in seaweed with multiple functional activities, is unstable with a poor water solubility that limits its utilization. This study aimed to improve FX's stability and bioavailability via the nano-encapsulation of FX in polyvinylpyrrolidone (PVP)-coated FX@PVP nanoparticles (NPs). The FX@PVP NPs were evaluated in terms of their morphology, stability, encapsulation efficiency (EE), loading capacity (LC), and in vitro release to optimize the encapsulation parameters, and a 1:8 FX:PVP ratio was found to perform the best with the highest EE (85.50 ± 0.19%) and LC (10.68 ± 0.15%) and improved FX stability. In addition, the FX@PVP NPs were shown to effectively deliver FX into Caco-2 cancer cells, and the accumulation of FX in these cancer cells showed pro-oxidative activities to ameliorate H2O2-induced damage and cell death. The FX@PVP NPs could potentially become a new therapeutical approach for targeted cancer treatment.

Biological autoluminescence as a noninvasive monitoring tool for chemical and physical modulation of oxidation in yeast cell culture

Normal or excessive oxidative metabolism in organisms is essential in physiological and pathophysiological processes, respectively. Therefore, monitoring of biological oxidative processes induced by the chemical or physical stimuli is nowadays of extreme importance due to the environment overloaded with various physicochemical factors. Current techniques typically require the addition of chemical labels or light illumination, which perturb the samples to be analyzed. Moreover, the current techniques are very demanding in terms of sample preparation and equipment. To alleviate these limitations, we propose a label-free monitoring tool of oxidation based on biological autoluminescence (BAL). We demonstrate this tool on Saccharomyces cerevisiae cell culture. We showed that BAL can be used to monitor chemical perturbation of yeast due to Fenton reagents initiated oxidation-the BAL intensity changes with hydrogen peroxide concentration in a dose-dependent manner. Furthermore, we also showed that BAL reflects the effects of low-frequency magnetic field on the yeast cell culture, where we observed a disturbance of the BAL kinetics in the exposed vs. control case. Our results contribute to the development of novel techniques for label-free, real-time, noninvasive monitoring of oxidative processes and approaches for their modulation.

An upgraded and universal strategy to reinforce chitosan/polyvinylpyrrolidone film by incorporating active silica nanorods derived from natural palygorskite

Active silica nanorod (OPal) was prepared from natural palygorskite (RPal) using an updated acid leaching route, and then the effect of RPal and OPal as nano-filler on the network structure, mechanical, thermal and anti-aging properties of chitosan/polyvinylpyrrolidone (CS/PVP) films was studied comparatively. It was revealed that OPal had a better dispersibility than RPal in CS/PVP substrate, and its incorporation improved the mechanical properties and thermal stability of the films significantly. The optimal composite film containing OPal shows the maximum tensile strength of 27.53 MPa (only 14.87 MPa and 22.47 MPa for CS/PVP and CS/PVP/RPal films, respectively), resulting from the more uniform dispersion of OPal in polymer substrate and its stronger interaction with 3D polymer network. By a controllable acid-leaching process, the metal ions in octahedral sheets of RPal were dissolved out continuously, which is favorable to alleviate the adverse effects of variable metal ions on the film under UV light irradiation, and thus improve the aging-resistant ability of films. This study provides new ideas for improving the reinforcing ability of natural clay minerals towards biopolymer-based material, finds a new way to resolve the aging problem of polymer composites caused by incorporation of natural clay minerals.

Peculiarities of Cell Seeding on Electroformed Polycaprolactone Scaffolds Modified with Surface-Active Agents Triton X-100 and Polyvinylpyrrolidone

We compared the capability of human fibroblasts to populate porous polycaprolactone (PCL) scaffolds modified during fabrication with surface-active agents Triton Х-100 (type 1 scaffold) and polyvinylpyrrolidone (type 2 scaffold). The mean fiber diameter in both scaffolds was almost the same: 3.90±2.19 and 2.46±2.15 μ, respectively. Type 1 scaffold had higher surface density and hydrophilicity, when type 2 scaffold was 1.6 times thicker. The cells were seeded on the scaffolds by the dynamic seeding technique and then cultured in Petri dishes with nutrient medium in a humid atmosphere. During 3-day culturing, no cell release from the matrix was noted. DAPI staining proved the presence of cells in both scaffolds. However, in type 1 scaffold the cells populated the whole thickness, while in type 2 scaffold, the cells were present only in the superficial layer. These findings suggest that PCL scaffolds modified with Triton Х-100 or polyvinylpyrrolidone are not cytotoxic, but the structure of the scaffold treated with Triton Х-100 is more favorable for population with cells.

Sonochemical synthesis of PVA/PVP blend nanocomposite containing modified CuO nanoparticles with vitamin B1 and their antibacterial activity against Staphylococcus aureus and Escherichia coli

The aim of this paper was to blend the polymers, poly(N-vinyl-2-pyrrolidone) (PVP) and poly(vinyl alcohol) (PVA) to produce a novel composite materials possessing the benefits of both. CuO nanoparticles (NPs) were used as a suitable filler to fabricate the blend nanocomposites (NCs) with desired properties. First, the surface of NPs, was modified with vitamin B₁ (VB₁) as a bio-safe coupling agent. Then, the blend NCs with various ratios of modified CuO (3, 5, and 7 wt%) were fabricated under ultrasonic irradiations followed by casting/solvent evaporation method. These processes are fast and green way to disperse the NPs sufficiently. Several techniques were applied for the characterization of the obtained NCs. morphology examination demonstrated the morphology of NCs and compatibility of NPs with the blend polymer. EDX results indicated the weight and atomic percentage of the achieved materials. TGA analysis verified that the NCs show higher thermal properties than the neat blend polymer. Also embedding the modified NPs into the blend polymer had effected on optical absorbance of the obtained NCs. The contact angle measurements confirmed that the hydrophilicity decreased for different proportions of the modified NPs loaded in the blend polymer. Finally, NCs show better bactericidal effects against gram-positive than gram-negative bacteria.

Reducing Facial Wrinkle Size and Increasing Skin Firmness Using Skin Care Polymers

Many cosmetic polymers shrink on drying, producing a tensile force if coated on a substrate. This tensile force can be used to smoothen wrinkles and pores in facial skin. In this study, we evaluated two polymers, a polyvinylpyrrolidone (PVP) and a polyacrylate, for skin tightening properties. We conducted a double-blinded, placebo-controlled and randomized clinical study with 32 female volunteers aged 35-65 years who perceived themselves to have a loss of skin elasticity. Both polymers were formulated in a model cosmetic emulsion with hydrogenated polyisobutene as the oil phase. We measured skin firmness and tightening parameters at baseline and after each product application. Also, facial images were recorded with a fringe projection instrument. The firming measurements indicated that both polymers instantly tightened facial skin, whereas the placebo product offered no significant tightening benefit. However, in clinical evaluation, only the polyacrylate polymer produced statistically significant improvements in wrinkle size and skin firmness on the face without significant consumer use complaints such as tackiness. We concluded that skin care products using PVP and polyacrylates have the potential to offer immediate and visible benefits to consumers with aged skin.

Cryopreservation Protocols for Human Adipose Tissue Derived Adult Stem Cells

The development of simple but effective storage protocols for adult stem cells will greatly enhance their use and utility in tissue-engineering applications. Cryopreservation has shown to be most promising but is a fairly complex process, necessitating the use of chemicals called cryoprotective agents (CPAs), freezing equipment, and obviously, storage in liquid nitrogen. The purpose of this chapter is to present a general overview of cryopreservation storage techniques and the optimal protocols/results obtained in our laboratory for long-term storage of adult stem cells using freezing storage.

Complete in vitro oogenesis: retrospects and prospects

Precise control of mammalian oogenesis has been a traditional focus of reproductive and developmental biology research. Recently, new reports have introduced the possibility of obtaining functional gametes derived in vitro from stem cells. The potential to produce functional gametes from stem cells has exciting applications for regenerative medicine though still remains challenging. In mammalian females ovulation and fertilization is a privilege reserved for a small number of oocytes. In reality the vast majority of oocytes formed from primordial germ cells (PGCs) will undergo apoptosis, or other forms of cell death. Removal occurs during germ cell cyst breakdown and the establishment of the primordial follicle (PF) pool, during the long dormancy at the PF stage, or through follicular atresia prior to reaching the ovulatory stage. A way to solve this limitation could be to produce large numbers of oocytes, in vitro, from stem cells. However, to recapitulate mammalian oogenesis and produce fertilizable oocytes in vitro is a complex process involving several different cell types, precise follicular cell-oocyte reciprocal interactions, a variety of nutrients and combinations of cytokines, and precise growth factors and hormones depending on the developmental stage. In 2016, two papers published by Morohaku et al. and Hikabe et al. reported in vitro procedures that appear to reproduce efficiently these conditions allowing for the production, completely in a dish, of a relatively large number of oocytes that are fertilizable and capable of giving rise to viable offspring in the mouse. The present article offers a critical overview of these results as well as other previous work performed mainly in mouse attempting to reproduce oogenesis completely in vitro and considers some perspectives for the potential to adapt the methods to produce functional human oocytes.

Influence of Poly(vinylpyrrolidone) concentration on properties of silver nanoparticles manufactured by modified thermal treatment method

Very narrow and pure silver nanoparticles were synthesized by modified thermal treatment method via oxygen and nitrogen flow in succession. The structural and optical properties of the calcined silver nanoparticles at 600°C with diverse Poly(vinylpyrrolidone) concentrations varied from 2% to 4% were studied by means of different techniques. Fourier transform infrared spectroscopy was used to monitor the production of pure Ag nanoparticles at a given Poly(vinylpyrrolidone) concentration. The X-ray powder diffraction spectra are evidence for the transformation of the amorphous sample at 30°C to the cubic crystalline nanostructures at the calcination temperatures for all Poly(vinylpyrrolidone) concentrations. The transmission electron microscopy images showed the creation of spherical silver nanoparticles with the average particle size decreased by increasing Poly(vinylpyrrolidone) concentrations from 4.61 nm at 2% to 2.49 nm at 4% Poly(vinylpyrrolidone). The optical properties were investigated by means of UV-vis absorption spectrophotometer, which showed an increase in the conduction band of Ag nanoparticles with increasing Poly(vinylpyrrolidone) concentrations from 2.83 eV at 2% Poly(vinylpyrrolidone) to 2.94 eV at 4% Poly(vinylpyrrolidone) due to decreasing particle size. This was due to less attraction between conduction electrons and metal ions for smaller particle size corresponding to fewer atoms that made up the metal nanoparticles.

Synthesis of platinum nanoparticles using seaweed Padina gymnospora and their catalytic activity as PVP/PtNPs nanocomposite towards biological applications

In the recent years, synthesis of nanomaterials using seaweeds and their diverse applications is escalating research in modern era. Among the noble metals, platinum nanoparticles (PtNPs) are of great importance owing to their catalytic property and less toxicity. The significance of this work is a simple one-step synthesis of PtNPs using aqueous extract of Indian brown seaweed Padina gymnospora and their catalytic activity with a polymer Polyvinylpyrrolidone (PVP) as PVP/PtNPs nanocomposite towards antimicrobial, haemolytic, cytotoxic (Artemia salina) and antioxidant properties. Fourier Transform Infrared (FT-IR) spectrum results showed diversified functional groups (biomoeities such as carbohydrates and proteins) present in the seaweed extract is responsible for the reduction of platinum ions (Pt+) to PtNPs. The seaweed mediated PtNPs was characterized by UV-vis spectrophotometer, X-ray diffraction (XRD) pattern, Field Emission Scanning Electron Microscopy (FESEM) equipped with Energy Dispersive X-ray (EDX) spectroscopy and High Resolution Transmission Electron Microscopy (HRTEM) analysis. The synthesized PtNPs was found to be truncated octahedral in shape with the range of 5-50nm. Crystalline nature of the nanoparticles was evidenced by Selected Area Electron Diffraction (SAED) pattern with bright circular spots corresponding to (111), (200), (220) and (311) Bragg's reflection planes. The size of the PtNPs was further evidenced by Dynamic Light Scattering (DLS) analysis and it is originate to be stable at -22.5mV through Zeta Potential (ZP) analysis. The present study shows that the catalytic behavior of PtNPs as polymer/metal nanocomposite (PVP/PtNPs) preparation for an antibacterial activity against seven disease causing pathogenic bacterial strains with the maximum activity against Escherichia coli (15.6mm) followed by Lactococcus lactis (14.8mm) and Klebsiella pneumoniae (14.4mm). But no haemolytic activity was seen at their effective bactericidal concentration, whereas increase in the haeomyltic activity was seen only in higher concentrations (600, 900 and 1200μgmL-1). On the other hand, PVP/PtNPs nanocomposite has shown cytotoxic activity at 100±4μgmL-1 (LC50) against Artemia salina nauplii. Furthermore, PVP/PtNPs nanocomposite showed an enhanced scavenging activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH), superoxide, nitric oxide and hydroxyl radicals.

Polyvinyl Pyrrolidone: A Novel Cryoprotectant in Islet Cell Cryopreservation

The present study was performed on the basis of the hypothesis that the low molecular weight (MW) compounds, DMSO and glycerol, permeate the cell and interact hydrophobically with intracellular proteins, thereby perturbing the cytoskeletal architecture of frozen cells and diminishing islet cell integrity and function. Isolated rat islets were cultured overnight (18–24 h) at 37°C in RPMI medium supplemented with 10% fetal calf serum and 1% mixture of penicillin/streptomycin. Using a programmable temperature controller, samples of precounted islets were then frozen under liquid nitrogen, in the presence of either 2 M DMSO (MW = 0.078 kDa), 3 M glycerol (MW = 0.092 kDa), 5% polyethylene glycol (PEG, MW = 20 kDa), or 10% polyvinylpyrrolidone (PVP, MW = 40 kDa), and stored at −80°C for 1 week. Following thawing and overnight (18–24 h) culture, intact islet recovery was determined by islet counting after dithizone staining. Islet function was assessed by determination of glucose-stimulated insulin secretion in perifusion experiments with Krebs-Ringer bicarbonate buffer, pH 7.4, containing either basal (3.3 mM) or high (16.7 mM) glucose concentrations. The assessment of islet recovery and function of all cryopreserved samples was performed only after thawing and overnight culture (18–24 h) of islets. The mean ± SEM percent intact islet recovery was higher with PVP compared with DMSO (82 ± 4.6 vs. 62.7 ± 3.1%, respectively, p < 0.005, n = 9). Furthermore, the glucose stimulation index of insulin secretion by islets taken from samples frozen with PEG and PVP, after thawing and overnight culture, was comparable to that of freshly isolated islets, in contrast to DMSO and glycerol. There was no significant difference in intact islet recovery and function between samples frozen with PVP and those frozen with PEG. Samples frozen with DMSO and glycerol had similar results in islet recovery and function. These data show that PVP is a new and potent cryoprotectant for islet cell freezing.

Activation of autophagy by elevated reactive oxygen species rather than released silver ions promotes cytotoxicity of polyvinylpyrrolidone-coated silver nanoparticles in hematopoietic cells

Silver nanoparticles (AgNPs) are the most commonly used engineered nanomaterials in commercialized products because of their antimicrobial activity. Previously, we have shown that polyvinylpyrrolidone (PVP)-coated AgNPs have an anti-leukemia effect against human myeloid leukemia cells; however, whether AgNPs are able to trigger autophagy in normal hematopoietic cells and the role of autophagy in AgNP-induced cytotoxicity remain unclear. In the current study, we observed that AgNPs were taken up by murine pro-B cells (Ba/F3), and then promoted accumulation of autophagosomes, which resulted from the induction of autophagy rather than the blockade of autophagic flux. AgNPs induced cytotoxicity in a dose-dependent manner accompanied by apoptosis and DNA damage through the production of reactive oxygen species (ROS) and the release of silver ions. The ROS-mediated mTOR signaling pathway was responsible for the induction of autophagy. More importantly, the inhibition of autophagy with the addition of 3-methyladenine (3-MA) or silencing of Atg5 significantly attenuated the cytotoxicity of AgNPs in Ba/F3. These findings suggest that autophagy is involved in the cytotoxicity of PVP-coated AgNPs in normal hematopoietic cells, and the inhibition of autophagy is a novel and potent strategy to protect normal hematopoietic cells upon treatment with AgNPs.

Colorimetric detection of endogenous hydrogen sulfide production in living cells

Hydrogen sulfide (H₂S) has received great attention as a third gaseous signal transmitter, following nitric oxide and carbon monoxide. In particular, H₂S plays an important role in the regulation of cancer cell biology. Therefore, the detection of endogenous H₂S concentrations within biological systems can be helpful to understand the role of gasotransmitters in pathophysiology. Although a simple and inexpensive method for the detection of H₂S has been developed, its direct and precise measurement in living cells remains a challenge. In this study, we introduced a simple, facile, and inexpensive colorimetric system for selective H₂S detection in living cells using a silver-embedded Nafion/polyvinylpyrrolidone (PVP) membrane. This membrane could be easily applied onto a polystyrene microplate cover. First, we optimized the composition of the coating membrane, such as the PVP/Nafion mixing ratio and AgNO₃ concentration, as well as the pH of the Na₂S (H₂S donor) solution and the reaction time. Next, the in vitro performance of a colorimetric detection assay utilizing the silver/Nafion/PVP membrane was evaluated utilizing a known concentration of Na₂S standard solution both at room temperature and at 37°C in a 5% CO₂ incubator. As a result, the sensitivity of the colorimetric assay for H₂S at 37°C in the incubator (0.0056Abs./μM Na₂S, R²=0.9948) was similar to that at room temperature (0.0055Abs./μM Na₂S, R²=0.9967). Moreover, these assays were less sensitive to interference from compounds such as glutathione, l-cysteine (Cys), and dithiothreitol than to the H₂S from Na₂S. This assay based on the silver/Nafion/PVP membrane also showed excellent reproducibility (2.8% RSD). Finally, we successfully measured the endogenous H₂S concentrations in live C6 glioma cells by s-(5'-adenosyl)-l-methionine stimulation with and without Cys and l-homocysteine, utilizing the silver/Nafion/PVP membrane. In summary, colorimetric assays using silver/Nafion/PVP-coated membranes can be simple, robust, and reliable tools for the detection of H₂S that can avoid the complicated and labor-intensive analytical approach used in conventional biology. In addition, we expect that this assay will demonstrate a powerful ability to study pathophysiological pathways that involve H₂S.

Changes in the membrane carbohydrates from sperm cryopreserved with dimethylsulfoxide or polyvinylpyrrolidone of red-tailed hawk (Buteo jamaicencis)

BACKGROUND

That cryopreservation can induce alterations in sperm.

OBJECTIVE

The goal of this study was to evaluate sperm quality and distribution of N-acetylglucosamine, sialic acid and mannose residues in sperm cryopreserved of red-tailed hawk (Buteo jamaicensis).

MATERIALS AND METHODS

We studied twenty samples of ejaculated semen for each cryoprotectant dimethylsulfoxide or polyvinylpyrrolidone. Carbohydrate identification was carried out with lectins Triticum vulgaris agglutinin to N-acetylglucosamine and sialic acid and Concanavalia ensiformis for mannose residues. Sperm viability was not altered but motility decreased significantly with both crioprotectants compared with fresh sperm.

RESULTS

Neither the number of WGA positive sperm nor the distribution of N-acetylglucosamine and/or sialic acid residues were affected by the cryopreservation procedure. The sperm proportion with fluorescence associated with the presence of mannose residues was higher in thawed sperm.

CONCLUSION

Values obtained with the cryopreservation technique proposed in this study by freezing drops in liquid nitrogen, were within normal parameters established for good quality fresh semen. We can say that it can be used for assisted reproduction of Buteo jamaicensis.

Multi-Functional Nanogels for Tumor Targeting and Redox-Sensitive Drug and siRNA Delivery

(1) Background: A new family of nanosystems able to discern between normal and tumor cells and to release a therapeutic agent in controlled way were synthetized by e-beam irradiation. This technique permits to obtain biocompatible, sterile, carboxyl-functionalized polyvinylpyrrolidone (PVP-co-acrylic acid) nanogels (NGs); (2) Methods: Here, we performed a targeting strategy based on the recognition of over-expressed proteins on tumor cells, like the folate receptor. The selective targeting was demonstrated by co-culture studies and flow cytometry analysis, using folate conjugated NGs. Moreover, nanoparticles were conjugated to a chemotherapeutic drug or to a pro-apoptotic siRNA through a glutathione sensitive spacer, in order to obtain a controlled release mechanism, specific for cancer cells. The drug efficiency was tested on tumor and healthy cells by flow cytometric analysis, confocal and epifluorescence microscopy and cytotoxicity assay; the siRNA effect was investigated by RNAi experiment; (3) Results: The data obtained showed that the use of NGs permits a faster cargo release in cancer cells, in response to high cytosolic glutathione level, also improving their efficacy; (4) Conclusion: The possibility of releasing biological molecules in a controlled way and to recognize a specific tumor target allows overcoming the typical limits of the classic cancer therapy.

[Toxicological evaluation of nanosized colloidal silver, stabilized with polyvinylpyrrolidone, in 92-day experiment on rats. II. Internal organs morphology]

The aim of the study was to evaluate the safe doses of commercially available nanosized colloidal silver (NCS), stabilized with polyvinilpirrolidone (PVP, food additive E1201) when administered in gastrointestinal tract of rats in the 92-day experiment in terms of the morphological changes in the internals of animals. The sample studied contained non-aggregated nanoparticles (NPs) of silver belonging to size fractions with a diameter of less than 5 nm, 10-20 nm or 50-80 nm. 80% of NPs were inside the range of hydrodynamic diameters 10.6-61.8 nm. The preparation of NCS was administered to growing male Wistar rats. (initial body weight 80 ± 10 g) for 1 month by intragastric gavage and then consumed with food at doses of 0.1, 1.0 and 10 mg/kg of body weight based on silver. The control animals received water or vehicle of nanomaterial--water solution of PVP. After withdrawal of animals from the experiment by exsanguination under ether anesthesia organs (liver, spleen, kidney, ileum) were isolated and their slides were prepared by standard methods following 'by staining with hematoxylin-eosin. Analysis was performed in light optical microscope equipped with a digital camera at a magnification from 1 x 100 to 1 x 1000. It was shown that the experimental animals treated with the NCS developed series of morphological changes in the tissues of the internal organs (liver, spleen and kidney) with the elevation of the range and severity of structural changes with increasing doses of silver. The most sensitive target of NCS action was apparently liver, which has already shown at a dose of 0.1 mg of silver NP/kg of body weight marked eosinophilic infiltration of portal tracts, which was accompanied at doses of 1.0 and 10.0 mg/kg by the emergence of medium and large-drop fat vacuoles in the cytoplasm of hepatocytes, swelling and lympho-macrophage. infiltration of the portal tracts. Detectable changes can be regarded as symptoms of inflammation of hepatocytes, at least, at a dose nanomaterial of 1.0 mg/kg body weight or more. Relative intensity of morphological changes in the internal organs correlated with published data on the biodistribution of silver NP administered to the gastrointestinal tract. It is concluded that the threshold dose corresponding to the minimum adverse effect of NCS is, according to the study of the above, no more than 1.0 mg/kg of body weight based on silver.

Iron Oxide@PEDOT-Based Recyclable Photothermal Nanoparticles with Poly(vinylpyrrolidone) Sulfobetaines for Rapid and Effective Antibacterial Activity

Growing microbial resistance that renders antibiotic treatment vulnerable has emerged, attracting a great deal of interest in the need to develop alternative antimicrobial treatments. To contribute to this effort, we report magnetic iron oxide (Fe3O4) nanoparticles (NPs) coated with catechol-conjugated poly(vinylpyrrolidone) sulfobetaines (C-PVPS). This negatively charged Fe3O4@C-PVPS is subsequently encapsulated by poly(3,4-ethylenedioxythiophene) (PEDOT) following a layer-by-layer (LBL) self-assembly method. The obtained Fe3O4@C-PVPS:PEDOT nanoparticles appear to be novel NIR-irradiated photothermal agents that can achieve effective bacterial killing and are reusable after isolation of the used particles using external magnetic fields. The recyclable Fe3O4@C-PVPS:PEDOT NPs exhibit a high efficiency in converting photothermal heat for rapid antibacterial effects against Staphylococcus aureus and Escherichia coli. In this study, antibacterial tests for repeated uses maintained almost 100% antibacterial efficiency during three cycles and provided rapid and effective killing of 99% Gram-positive and -negative bacteria within 5 min of near-infrared (NIR) light exposure. The core-shell nanoparticles (Fe3O4@C-PVPS:PEDOT) exhibit the required stability, and their paramagnetic nature means that they rapidly convert photothermal heat sufficient for use as NIR-irradiated antibacterial photothermal sterilizing agents.

Expression of proapoptotic BAX and TP53 genes and antiapoptotic BCL-2 gene in MCF-7 and T-47D tumour cell cultures of the mammary gland after a photodynamic therapy with photolon

BACKGROUND

Breast cancer is the most common malignant tumour in women in the whole world. Despite significant developments in the early diagnosis of breast cancer, there is no effective method which would assure total recovery of the patient. Currently available clinical data and laboratory tests indicate a possibility to introduce photodynamic therapy (PDT) to the supplementary treatment of breast cancer.

OBJECTIVES

The aim of this study was to assess the influence of PDT with Photolon as a photosensibilizator on the expression of apoptosis associated genes (BCL-2, BAX, TP53) in human breast cancer cell lines, preceded by assessment of survivorship and proliferative activity in the tested cells after PDT.

MATERIAL AND METHODS

In the present study human breast cancer cell lines MCF-7 and T-47D were used. Photolon (chlorin e6 complex: PVP 1:1) was used as a photosensitizer. Assessments of survivorship and proliferative activity of cells under the influence of PDT (WST-1 test) were conducted along with the expression of selected genes involved in the process of apoptosis: BCL-2, BAX, TP53 (RT-QPCR).

RESULTS

PDT limited both survivorship and proliferative activity of breast cancer cells in the two tested lines. In case of T-47D cell line was found increase of BAX and BCL-2 genes expression after PDT and sustained activity of TP53 gene. Conversely, in MCF-7 cell line a decrease in expression was found for both BAX and TP53 genes, but also an increase of BCL-2 gene expression.

CONCLUSIONS

A progressing decrease (24, 48 and 72 h after PDT) in the count of culture cells, which suggests the occurrence of apoptosis initiated by a photodynamic reaction with simultaneous increase of BCL-2/BAX index, indicates activation of a different endogenous apoptosis pathway than the one examined, namely pointing to suicidal death of cells after PDT.

The expression of the 14D9 catalytic antibody in suspended cells of Nicotiana tabacum cultures increased by the addition of protein stabilizers and by transference from Erlenmeyer flasks to a 2-L bioreactor

The effect of two protein stabilizers (polyvinylpyrrolidone [PVP] and gelatine) on growth and 14D9 yield of Nicotiana tabacum cell suspension cultures (Ab-KDEL and sec-Ab) was analyzed. The addition of PVP at a concentration of 1.0 g L(-1) produced the highest total 14D9 yield (biomass + culture medium) in the Ab-KDEL line (4.82% total soluble protein [TSP]). With the addition of gelatine, the highest total 14D9 yield (2.48% TSP) was attained in the Ab-KDEL line at 5.0 g L(-1) gelatine. When the Ab-KDEL suspended cells were cultured in a 2-L bioreactor, the highest 14D9 yield was 8.1% TSP at a 5% w/v inoculum size, which was the best 14D9 yield so far obtained in the platforms tested (E. coli, N. tabacum leaves and seeds, N. tabacum hairy roots, and cell suspension cultures).

In vitro investigation of antioxidant, anti-Inflammatory, and antiplatelet adhesion properties of genistein-modified poly(ethersulfone)/poly(vinylpyrrolidone) hemodialysis membranes

Hemocompatibility of genistein-modified poly(ethersulfone)/poly(vinylpyrrolidone) (PES/PVP) hemodialysis (HD) membranes has been investigated in vitro with emphasis on evaluation of cell viability, antioxidant, anti-inflammatory, and antiplatelet adhesion properties. Genistein modified PES/PVP membranes reveal significant reduction of the reactive oxygen species and also considerable suppression of interleukin-1β and tumor necrosis factor-α levels in whole blood, but to a lesser extent ininterleukin-6. The incorporation of PVP into the HD membrane reduces platelet adhesion by virtue of its hydrophilicity. Of particular importance is that platelet adhesion of the genistein modified membranes declines noticeably at low concentrations of genistein for about 5-10%, beyond which it raises the number of adhered platelets. The initial decline in the platelet adhesion is attributable to genistein's ability to inhibit intercellular and/or vascular cell adhesion, whereas the reversal of this adhesion trend with further increase of genistein loading is ascribed to the inherent hydrophobicity of the genistein modified HD membrane.

Anti-inflammatory effects of silver-polyvinyl pyrrolidone (Ag-PVP) nanoparticles in mouse macrophages infected with live Chlamydia trachomatis

Chlamydia trachomatis is a very common sexually transmissible infection in both developing and developed countries. A hallmark of C. trachomatis infection is the induction of severe inflammatory responses which play critical roles in its pathogenesis. Antibiotics are the only treatment option currently available for controlling C. trachomatis infection; however, they are efficacious only when administered early after an infection. The objectives of this study are to explore alternative strategies in the control and regulation of inflammatory responses triggered by a C. trachomatis infection. We employed silver-polyvinyl pyrrolidone (Ag-PVP) nanoparticles, which have been shown to possess anti-inflammatory properties, as our target and the in vitro mouse J774 macrophage model of C. trachomatis infection. Our hypothesis is that small sizes of Ag-PVP nanoparticles will control inflammatory mediators triggered by a C. trachomatis infection. Cytotoxicity studies using Ag-PVP nanoparticles of 10, 20, and 80 nm sizes revealed >80% macrophage viability up to a concentration of 6.25 μg/mL, with the 10 nm size being the least toxic. All sizes of Ag-PVP nanoparticles, especially the 10 nm size, reduced the levels of the prototypic cytokines, tumor necrosis factor (TNF) and interleukin (IL)-6, as elicited from C. trachomatis infected macrophages. Additionally, Ag-PVP nanoparticles (10 nm) selectively inhibited a broad spectrum of other cytokines and chemokines produced by infected macrophages. Of significance, Ag-PVP nanoparticles (10 nm) caused perturbations in a variety of upstream (toll like receptor 2 [TLR2], nucleotide-binding oligomerization-protein 2 [NOD2], cluster of differentiation [CD]40, CD80, and CD86) and downstream (IL-1 receptor-associated kinase 3 [IRAK3] and matrix metallopeptidase 9 [MMP9]) inflammatory signaling pathways by downregulating their messenger ribonucleic acid (mRNA) gene transcript expressions as induced by C. trachomatis in macrophages. Collectively, our data provides further evidence for the anti-inflammatory properties of Ag-PVP nanoparticles, and opens new possibilities for smaller sizes of Ag-PVP nanoparticles to be employed as regulators of inflammatory responses induced by C. trachomatis.

lGnRH-III -- a promising candidate for anticancer drug development

Lamprey gonadotropin-releasing hormone-III (lGnRH-III; Glp-His-Trp-Ser-His-Asp-Trp-Lys-Pro-Gly-NH2), a native isoform of human GnRH (GnRH-I), was initially isolated from the brain of the sea lamprey (Petromyzon marinus). It is a weak GnRH agonist, which exerts a direct antiproliferative effect on cancer cells and has an insignificant LH and FSH releasing potency in mammals. These features reveal the advantages of lGnRH-III and its derivatives for use in cancer therapy. Here we give an overview of various strategies to increase the antitumor activity of lGnRH-III, such as amino acid replacement, cyclization, dimerization and conjugation to polymers or to chemotherapeutic agents. In vitro and in vivo antitumor activity of lGnRH-III based compounds was demonstrated both on hormone dependent and independent tumors.

Large-scale and highly efficient synthesis of micro- and nano-fibers with controlled fiber morphology by centrifugal jet spinning for tissue regeneration

PLLA fibrous tissue scaffolds with controlled fiber nanoscale surface roughness are fabricated with a novel centrifugal jet spinning process. The centrifugal jet spinning technique is a highly efficient synthesis method for micron- to nano-sized fibers with a production rate up to 0.5 g min(-1). During the centrifugal jet spinning process, a polymer solution jet is stretched by the centrifugal force of a rotating chamber. By engineering the rheological properties of the polymer solution, solvent evaporation rate and centrifugal force that are applied on the solution jet, polyvinylpyrrolidone (PVP) and poly(l-lactic acid) (PLLA) composite fibers with various diameters are fabricated. Viscosity measurements of polymer solutions allowed us to determine critical polymer chain entanglement limits that allow the generation of continuous fiber as opposed to beads or beaded fibers. Above a critical concentration at which polymer chains are partially or fully entangled, lower polymer concentrations and higher centrifugal forces resulted in thinner fibers. Etching of PVP from the PLLA-PVP composite fibers doped with increasing PVP concentrations yielded PLLA fibers with increasing nano-scale surface roughness and porosity, which increased the fiber hydrophilicity dramatically. Scanning electron micrographs of the etched composite fibers suggest that PVP and PLLA were co-contiguously phase separated within the composite fibers during spinning and nano-scale roughness features were created after the partial etching of PVP. To study the tissue regeneration efficacy of the engineered PLLA fiber matrix, human dermal fibroblasts are used to simulate partial skin graft. Fibers with increased PLLA surface roughness and porosity demonstrated a trend towards higher cell attachment and proliferation.

Chromatin immunoprecipitation assay of brain tissues using Percoll gradient-purified nuclei

Protein-DNA interactions are critical to maintain genome stability, DNA replication, chromosome -segregation and to regulate gene expression. Chromatin immunoprecipitation (ChIP) is a powerful technique to study these interactions within living neurons and nervous tissue. In particular, ChIP analysis of chromatin in which protein-DNA interactions are first fixed in situ provides a valuable approach to identify specific transcription factor-DNA interactions and their regulation in the developing nervous system. Here we describe a procedure utilizing Percoll gradient purification of nuclei from fresh brain tissue pre-fixed with formaldehyde for ChIP analysis. This purification protocol provides an enrichment of neuronal nuclei in high yield. We also illustrate the suitability of chromatin prepared from Percoll-purified brain nuclei for ChIP analysis of regulated transcription factor interactions with neuronal gene promoters.

Direct and indirect method of plant regeneration from root explants of Caesalpinia bonduc (L.) Roxb.--a threatened medicinal plant of Western Ghats

An in vitro regeneration protocol has been standardized via direct and indirect methods from excised root explants of C. bonduc, a threatened woody legume used for the treatment of contagious diseases, inflammation, leprosy, antiperiodic, febrifuge, anthelmenthic, urinary disorders, leucorrhoea, piles and to heal wounds. MS medium supplemented with 17.75 micromol BAP and 2.46 micromol IBA, induced a mean of 3.40 +/- 1.07 shoots directly from the surface of excised root explant. Subsequently, the shoots rooted readily on MS half strength medium with out growth regulators. In indirect organogenesis, callogenic frequency was optimized (96.66%) at the concentration of 9.04 micromol 2, 4-D and 0.88 micromol BAP. An average, 15.30 +/- 5.25 shoots were differentiated from the root callus at the concentration of 17.57 micromol BAP and 2.85 micromol IAA. Shoots regenerated through callus were rooted well on MS half strength medium with growth regulators at 2.95 micromol IBA. Rooted plantlets were transferred to the pots containing sterilized soil and were successfully hardened at greenhouse condition for three weeks then exposed to the natural environment. Survival rate was more (95%) in plantlets derived through direct organogenesis than (60%) the plantlets regenerated through root calli.

Effects of combined sonodynamic and photodynamic therapies with photolon on a glioma C6 tumor model

The aim of this study was to investigate the low-power density sonication, sonodynamic therapy (SDT) with Photolon and combination of SDT and photodynamic therapy (PDT) with Photolon for the ablation of glioma C6 tumor model in rats.

METHODS

The study was performed on 50 rats bearing glioma C6. The tumors were sonicated with/without prior intravenous injection of photosensitizer (PS) Photolon (2.5 mg/kg b.w). Sonication was performed with 0.4; 0.7 and 1.0 W/cm² power density at 1 MHz frequency for 10 min, 2.0 h after Photolon administration using BTL-5710 Sono (BTL Industries Limited, Great Britain). PDT was carried out 2.5 h after Photolon administration using diode laser with 661 nm wavelength (IMAF-AXICON, Minsk, Republic of Belarus) at doses of 50 and 100 J/cm² with 0,17 W/cm² fluence rate. Assessment of tumor response was performed by vital staining with Evans blue and pathologic examination.

RESULTS

The maximal tumor necrosis area that underwent sonication (1 MHz; 0.7 W/cm²; 10 min.) followed by PDT at a dose of 100 J/cm² was 100%.

CONCLUSION

This is the first report to demonstrate the benefits of sono-photodynamic therapy (SPDT) consisting of low-power density ultrasound and PDT for the treatment of malignant glioma models.

[Antiamyloid properties of fullerene C60 derivatives]

A comparative estimation of the ability of complexes of fullerene C60 with polyvinylpyrrolidone and fullerene C60 derivatives (the sodium salt of the polycarboxylic derivative of fullerene C60, sodium fullerenolate), has been carried out. The fullerenes destroyed amyloid fibrils of the Abeta(1-42) peptide of the brain and the muscle X-protein. A study of the effect of fullerenes on muscle actin showed that complexes of fullerene C60 with polyvinylpyrrolidone and sodium fullerenolate did not prevent the filament formation of actin, nor did they destroy its filaments in vitro. Conversely, sodium salt of the polycarboxylic derivative of fullerene C60 destroyed actin filaments and prevented their formation. It was concluded that sodium fullerenolate and complexes of fullerene C60 with polyvinylpyrrolidone are the most effective antiamyloid compounds among the fullerenes examined.

Production and secretion of recombinant thaumatin in tobacco hairy root cultures

Production of recombinant proteins in plant cell or organ cultures and their secretion into the plant cell culture medium simplify the purification procedure and increase protein yield. In this study, the sweet-tasting protein thaumatin I was expressed and successfully secreted from tobacco hairy root cultures. The presence of an ER signal peptide appears to be crucial for the secretion of thaumatin: without an ER signal peptide, no thaumatin was detectable in the spent medium, whereas inclusion of the ER signal peptide calreticulin fused to the N terminus of thaumatin led to the secretion of thaumatin into the spent medium of hairy root cultures at concentrations of up to 0.21 mg/L. Extracellular thaumatin levels reached a maximum after 30 days (stationary phase) and the subsequent decline was linked to the rapid increase of proteases in the medium. Significant amounts of thaumatin were trapped in the apoplastic space of the root cells. The addition of polyvinylpyrrolidone and sodium chloride into the culture medium led to an increase of extracellular thaumatin amounts up to 1.4 and 2.63 mg/L, respectively. Thaumatin production compares well with yields from other transgenic plants, so that tobacco hairy roots can be considered an alternative production platform of thaumatin.

[Temperature regime of biological tissue under photodynamic therapy]

An analytical model is proposed to calculate heating of human skin cover under laser light action of photodynamic therapy. A photosensitizer of "Fotolon" is taken as an example. Temperatures of skin surface and of deep dermis regions are studied as a function of time under pulsed and stationary irradiation of skin surface at the wavelength of 665 nm corresponding to the maximum of the photosensitizer absorption band. It is shown that, under the action of a short light pulse, the photosensitizer can lead to an essential temperature rise of dermis due to a considerable increase in its absorption coefficient. However, this rise does not destruct tissue cells because of the short action. Under stationary irradiation, the photosensitizer concentration has a low effect on the temperature regime of tissue. This is related with the specific features in heating of the medium by red light, where the main thermal process in skin is heat transfer over tissue volume from epidermis having a substantially larger absorption coefficient than that of dermis in the said spectral range. The role of blood perfusion in dermis and its effect on the temperature regime of tissue are evaluated.

In vitro maturation supplements affect developmental competence of bovine cumulus-oocyte complexes and embryo quality after vitrification

Oocyte quality affects subsequent embryo development and quality. We examined the impact of bovine oocyte in vitro maturation (IVM) conditions on subsequent embryo yield, quality and cryosurvival. Cumulus-oocyte complexes (COCs) were sampled for cytological and gene expression analysis after IVM in TCM199 supplemented with 10% fetal bovine serum (FBS), 4 mg/ml of fatty-acid-free bovine serum albumin (FAFBSA), 4 mg/ml of polyvinylpyrrolidone (PVP), FAFBSA with epidermal growth factor (EGF, 100 ng/ml) and insulin-like growth factor 1 (IGF-I, 100 ng/ml) (FAFBSAGF), PVP with EGF and IGF-I (PVPGF) or PVP with single strength BME and MEM amino acids (PVPAA). The remaining COCs were fertilized. On day 7 (IVF=day 0) quality 1 blastocysts were vitrified or analyzed for glucose transporter 1 (Glut-1) expression levels. The remaining blastocysts (days 7-9) were evaluated for morphology and total cell counts. After warming, survival and hatching rates were evaluated followed by total cell counts and Glut-1 expression levels. Only PVPGF IVM resulted in embryo production rates comparable to those recorded with FBS IVM. Growth factors with FAFBSA and amino acids with PVP reduced embryo production rates whereas the effect of the growth factors with PVP was negligible. Insulin-like growth factor 2 binding protein 3 (IGF2BP3) and beta cell translocation gene 4 (BTG4) were revealed as potential candidates for oocyte developmental competence, and secreted protein, acidic and rich in cysteine (SPARC) for cumulus cell expansion. There were no differences among treatments in hatching rates of vitrified embryos after warming. However, total cell numbers and Glut-1 expression levels at 72 h were affected.

Photolon enhancement of ultrasound cytotoxicity

OBJECTIVE

To evaluate the impact of Photolon on cytostatic and cytotoxic effects of therapeutic range ultrasound in C6 glioma cells.

METHODS

C6 glioma cells in suspension or monolayer cell culture were exposed to ultrasound (880 kHz, 0.2-0.7 W/cm2) in the presence or absence of Photolon at the concentration of 1 μg/ml in the culture medium, and then cell viability was evaluated.

RESULTS

Photolon increased the cytotoxic effect of ultrasound by 1.5-2.3-fold but had no effect on its cytostatic activity.

CONCLUSION

Photolon produces a pronounced sonosensitizing effect on glioma C6 cells and is a promising drug for sonodynamic treatment of malignant tumors.

Surface characteristics of acrylic modified polysulfone membranes improves renal proximal tubule cell adhesion and spreading

Current polyvinylpyrrolidone-modified polysulfone (PVP-PSU) membranes in haemodialysers do not facilitate the attachment and proliferation of renal proximal tubule cells (RPTCs). For bioartificial kidney (BAK) development expensive extracellular matrices are employed to ensure the PVP-PSU membranes can serve as a substrate for RPTCs. In this study we modified PSU using an acrylic monomer (am-PSU) and polymerization using ultraviolet irradiation. We demonstrated that on adjusting the PSU or acrylic content of the membranes the wettability and surface chemistry were altered, and this affected the amount of fibronectin (Fn) that was adsorbed onto the membranes. Using an integrin blocking assay we ascertained that Fn is an important extracellular matrix component that mediates RPTC attachment. The amount of Fn adsorbed also led to different bioresponses of RPTCs, which were evaluated using attachment and proliferation assays and qualitative quantification of vinculin, focal adhesion kinase, zonula occludens and Na(+)/K(+) ATPase. Our optimized membrane, am-PSU1 (21.4% C-O groups, 19.1% PVP-PSU; contact angle 71.5-80.80, PVP-PSU: 52.4-67.50), supports a confluent monolayer of RPTCs and prevents creatinine and inulin diffusion from the apical to the basal side, meeting the requirements for application in BAKs. However, further in vivo evaluation to assess the full functionality of RPTCs on am-PSU1 is required.

Electrospun nano composites of poly(vinyl pyrrolidone)/ nano-silver for antibacterial materials

Poly(vinyl pyrrolidone) (PVP) and nanosilver are promising candidates for biomedical applications because of their biocompatibility and antibacterial efficacy, respectively. In this research, three kinds of nanosilver particles (NSPs) were prepared using the seed mediate growth method and added to electrospinning solutions. PVP/NSPs composites were prepared by electrospinning of 10 wt% PVP solutions that contained NSPs in ethanol. The electrospinability of PVP/NSPs nanowebs in ethanol was investigated according to three different concentrations of NSPs. The Electrospun PVP/NSPs nanocomposites were photocross-linked to improve their water stability. The antibacterial efficacy of the PVP/NSPs nanocomposites was assessed against three types of bacteria; Staphylococcus aureus, Klebsiella pneumoniae and Escherichia coli. The photocross-linked PVP/NSPs nanocomposites had high water stability and significant antibacterial efficacy against all three types of bacteria. Therefore, these composites could be applied as antimicrobial materials.

[Collagen-polyvinylpyrrolidone: a new therapeutic option for treatment of sequelae after radical mastectomy in women with breast cancer. Preliminary study]

BACKGROUND

Approximately 30% of women who undergo mastectomy without reconstructive treatment due to breast cancer present sequelae. These include paresthesias, keloid healing, hypoesthesia, lymphedema and limitation of the function of the ipsilateral upper extremity. We undertook this study to present the results using collagen-polyvinylpyrrolidone (Clg- Pvp) as treatment for posmastectomy sequelae in women with breast cancer.

METHODS

We conducted a unicentric, longitudinal and prospective clinical trial between August 1, 2007 and July 31, 2008. Included variables were age, lymphedema, limitation of the function of the ipsilateral upper extremity, collapse of the wound, keloid healing, paresthesias, and appearance of the surgical area. The appearance of the surgical area (aesthetic aspect) was evaluated before and 6 months after treatment was initiated. Clg-Pvp was administered weekly for a 6-month period.

RESULTS

Seven women were included with a median age of 49 years (range: 40-72 years). One patient (14.28%) presented lymphedema, two patients (28.57%) presented collapse of the wound, two patients (28.57%) had keloid healing, three patients (42.85%) experienced paresthesias, five patients (71.4%) reported pain, and five patients (71.4%) reported limitation of the function of the ipsilateral upper extremity. At the completion of the treatment, aesthetic improvement was statistically significant (p = 0.0020, Mann-Whitney U test).

CONCLUSIONS

Clinical and aesthetic results are good after application of Clg-Pvp for treating sequelae in women with breast cancer who underwent mastectomy without reconstructive surgery.

Synthesis of PVP-coated ultra-small Fe3O4 nanoparticles as a MRI contrast agent

Ultra-small Fe(3)O(4) nanoparticles were prepared by using the coprecipitation method, in which the polyvinylpyrrolidone (PVP) serves as a stabilizer. The nanoparticles were characterized by means of X-ray diffraction (XRD), transmission electron microscopy (TEM), infra spectrum (IR), X-ray photoelectron spectroscopy (XPS) and in vivo magnetic resonance imaging (MRI) test. The results showed that the particles' size was determined by the dripping rate and that PVP molecules played the role of preventing the aggregation and restricting the size of Fe(3)O(4) nanoparticles. The Fe(3)O(4) nanoparticles with diameter from 6.5 to 1.9 nm obviously exhibited negative contrast enhancement and concentrated at the target area guided by a permanent magnet.