Dual-Pulsed Laser Ablation of Oyster Shell Producing Novel Thin Layers Deposed to Saccharomyces cerevisiae.

Dual-pulsed (DPL) laser deposition using oyster shells as targets was studied in order to find out if this method can replace the use of high-power pulsed lasers. Aspects related to changes in the morphological structure of the thin layer but also to the chemical composition of the obtained thin layer were analyzed and compared with the target as well as with the thin layers obtained with a higher power pulsed laser in a single-pulsed (SPL) regime. Orthorhombic structures were noticed with Scanning Electron Microscopy for the thin film obtained in DPL mode compared to the irregular particles obtained in SPL mode. The deacetylation process during ablation was evidenced by Fourier Transform Infrared spectroscopy, resulting in chitosan-based thin films. The effect of the obtained thin films of chitosan on the cells of baker's yeast (Saccharomyces cerevisiae) was studied. Restoration of the yeast paste into initial yeast was noticed mainly when the hemp fabric was used as support for the coating with yeas which was after that coated with chitosan thin film produced by DPL method.

Synthesis, Characterization and Biocompatibility Evaluation of Novel Chitosan Lipid Micro-Systems for Modified Release of Diclofenac Sodium.

The purpose of our study was the obtaining, characterization and biocompatibility estimation of novel carrier systems for diclofenac. Diclofenac is a potent nonsteroidal anti-inflammatory drug with frequent gastrointestinal side effects, impairing the quality of the patient's life. Original diclofenac-loaded micro-vesicles coated with chitosan were prepared and physico-chemical analyzed. We investigated their in vitro hemocompatibility and in vivo biocompatibility in rats. The animals were treated orally as follows: group 1 (Control): distilled water 0.3 mL/100 g body weight; Group 2 (CHIT): 0.3 mL/100 g body weight 0.5% chitosan solution; Group 3 (DCF): 15 mg/kg body weight diclofenac; Group 4 (DCF-ves): lipid vesicles loaded with diclofenac 15 mg/kg body weight. Blood samples were collected for assessing: red blood cells, hemoglobin, hematocrit and leukocyte formula. A series of specific parameters of the liver and kidney function, some markers of immune defense, as well as the activity of some enzymes involved in oxidative processes, were also investigated. At the end of the experiment, the animals were sacrificed and fragments of liver, kidney and stomach were collected for histopathological examination. No blood hemolysis was evidenced by the in vitro test with the administration of diclofenac vesicles. The animals treated with diclofenac lipid vesicles stabilized with chitosan did not display any notable differences in their hematological and biochemical profile compared to control animals. These data correlated with the histological results, which showed the absence of architectural changes in the examined tissues. Biological in vitro and in vivo evaluation revealed that the microvesicles containing diclofenac are biocompatible, with potential to be used as delivery systems to modify the drug release, thus making them an attractive candidate for biomedical applications.

Chitosan Soft Matter Vesicles Loaded with Acetaminophen as Promising Systems for Modified Drug Release.

Our study was designed to acquire, characterize and evaluate the biocompatibility of novel lipid vesicles loaded with acetaminophen (APAP) and coated with chitosan (CS). We investigated the in vitro and in vivo drug release kinetics from these systems, and we conducted assessments for both in vitro hemocompatibility and in vivo biocompatibility. For the in vivo biocompatibility evaluation, the mice were randomly divided into four groups of six animals and were treated orally as follows: control group: 0.1 mL/10 g body weight of double-distilled water; CS group: 0.1 mL/10 g body weight 1% CS solution; APAP group: 150 mg/kg body weight APAP; APAP-v group: 150 mg/kg body weight APAP-loaded lipid vesicles. The impact of APAP-v on various hematological, biochemical, and immune parameters in mice were assessed, and the harvested tissues were subjected to histopathological examination. The innovative formulations effectively encapsulating APAP within soft vesicles exhibited reasonable stability in solution and prolonged drug release in both in vitro and in vivo studies. The in vitro hemolysis test involving APAP-loaded vesicles revealed no signs of damage to red blood cells. The mice treated with APAP-v showed neither significant variances in hematological, biochemical, and immune parameters, nor structural changes in the examined organ samples, compared to the control group. APAP-v administration led to prolonged drug release. We can conclude that the APAP-v are innovative carrier systems for modifying drug release, making them promising candidates for biomedical applications.

The Analysis of Chitosan-Coated Nanovesicles Containing Erythromycin-Characterization and Biocompatibility in Mice.

Nanoantibiotics have proved improved pharmacokinetic characteristics and antimicrobial features. Recent studies have shown non-toxicity, non-immunogenicity, antioxidant, anti-hyperlipidemic, and hepatocyte protective actions, among other advantages of chitosan-based nanoparticles. The purpose of our study was the structural analysis of novel chitosan-coated vesicles entrapping erythromycin (ERT) and the assessment of their biocompatibility in mice. According to the group in which they were randomly assigned, the mice were treated orally with one of the following: distilled water; chitosan; ERT; chitosan vesicles containing ERT. Original nanosystems entrapping ERT in liposomes stabilized with chitosan were designed. Their oral administration did not produce sizeable modifications in the percentages of the leukocyte formula elements, of some blood constants useful for evaluating the hepatic and renal function, respectively, and of some markers of oxidative stress and immune system activity, which suggests a good biocompatibility in mice. The histological examination did not reveal significant alterations of liver and kidney architecture in mice treated with chitosan liposomes entrapping ERT. The results indicate the designed liposomes are a promising approach to overcome disadvantages of conventional ERT treatments and to amplify their benefits and can be further studied as carrier systems.

Study of Physico-Chemical Interactions during the Production of Silver Citrate Nanocomposites with Hemp Fiber.

In the study presented in this paper, the results obtained by producing nanocomposites consisting of a silver citrate thin layer deposited on hemp fiber surfaces are analyzed. Using the pulsed laser deposition (PLD) method applied to a silver target with impurities of nickel and iron, the formation of the silver citrate film is performed in various ways and the results are discussed based on Fourier Transform Infrared (FTIR) and Scanning Electron Microscopy coupled with Energy Dispersive X-ray (SEM-EDX) spectroscopy analyses. A mechanism of the physico-chemical processes that take place based on the FTIR vibrational modes and the elemental composition established by the SEM-EDS analysis is proposed. Inhibition of the fermentation process of Saccharomyces cerevisae is demonstrated for the nanocomposite material of the silver citrate thin layer, obtained by means of the PLD method, on hemp fabric. The usefulness of composite materials of this type can extend from sensors and optoelectronics to the medical fields of analysis and treatment.

Assessment of the In Vivo Release and Biocompatibility of Novel Vesicles Containing Zinc in Rats.

This paper is focused on the in vivo release and biocompatibility evaluation in rats of some novel systems entrapping zinc chloride in lipid vesicles. The particles were prepared by zinc chloride immobilization inside lipid vesicles made using phosphatidylcholine, stabilized with 0.5% chitosan solution, and dialyzed for 10 h to achieve a neutral pH. The submicrometric systems were physico-chemically characterized. White Wistar rats, assigned into four groups of six animals each, were treated orally with a single dose, as follows: Group I (control): deionized water 0.3 mL/100 g body weight; Group II (Zn): 2 mg/kg body weight (kbw) zinc chloride; Group III (LV-Zn): 2 mg/kbw zinc chloride in vesicles; Group IV (LVC-Zn): 2 mg/kbw zinc chloride in vesicles stabilized with chitosan. Haematological, biochemical, and immune parameters were assessed after 24 h and 7 days, and then liver fragments were collected for histopathological examination. The use of zinc submicrometric particles-especially those stabilized with chitosan-showed a delayed zinc release in rats. No substantial changes to blood parameters, plasma biochemical tests, serum complement activity, or peripheral neutrophils phagocytic capacity were noted; moreover, the tested substances did not induce liver architectural disturbances. The obtained systems provided a delayed release of zinc, and showed good biocompatibility in rats.

Biocompatibility and Pharmacological Effects of Innovative Systems for Prolonged Drug Release Containing Dexketoprofen in Rats.

The present study reports on the in vivo biocompatibility investigation and evaluation of the effects of liposomes containing dexketoprofen in somatic sensitivity in rats. METHOD: The liposomes were prepared by entrapping dexketoprofen in vesicular systems stabilized with chitosan. The in vivo biocompatibility was evaluated after oral administration in white Wistar rats: Group I (DW): distilled water 0.3 mL/100 g body weight; Group II (DEX): dexketoprofen 10 mg/kg body weight (kbw); Group III (nano-DEX): liposomes containing dexketoprofen 10 mg/kbw. Blood samples were collected from caudal lateral vein one day and seven days after the substance administration, to assess the eventual hematological, biochemical, and immunological changes. The investigation of somatic pain reactivity was performed using the hot plate test, to count the latency time response evoked by the thermal paws' noxious stimulation. RESULTS: Original liposomes entrapping dexketoprofen, with mean size of 680 nm and good stability, were designed. Laboratory analysis indicated no substantial variances between the three treated groups. The treatment with liposomes containing dexketoprofen resulted in a prolongation of the latency time response, statistically significant in the interval between 90 min and 10 h, in the hot plate test. CONCLUSIONS: The use of liposomes with dexketoprofen proved a good in vivo biocompatibility in rats and prolonged analgesic effects in the hot plate test.

Citrate-silver nanoparticles and their impact on some environmental beneficial fungi.

Colloidal suspensions of silver nanoparticles (AgNPs) with surface modified by capping with citrate ions were synthesized by chemical reduction method. Transmission and Scanning Electron Microscopy as well as darkfield Optical Microscopy provided information on the nanoparticle morphology, with fine symmetrical grains and log-normal fitted size distribution. Small Angle X-ray Scattering method allowed theoretical confirmation of colloidal silver nanoparticle fine granularity, based on measurements in the native fluid sample. UV-Vis spectrophotometry allowed studying the Localized Surface Plasmon Resonance band versus the stability of the citrate-AgNP sample after storage and after UV-C exposure. The colloidal AgNP impact on Phanerochaete chrysosporium environmental microorganisms was studied by specific biochemical investigations. Silver released from the colloidal suspension of AgNPs was supposed to induce changes in some antioxidant enzymes and in some enzymes of Krebs' cycle. Catalase activity was moderately changed (an increase with over 50%) as well as superoxide dismutase activity, while the diminution of the activities of four dehydrogenases synthesized in the fungus mycelium was emphasized also: a decrease with about 60% for malate dehydrogenase, with over 50% for isocitrate dehydrogenase and succinate dehydrogenase and with about 40% for alpha-ketoglutarate dehydrogenase. These findings suggested the nano-toxicological issues of citrate-AgNPs impact on the environmental beneficial microorganisms.

Effect of TAT-DOX-PEG irradiated gold nanoparticles conjugates on human osteosarcoma cells.

The paper aims to investigate the cytotoxic effect on tumor cells of irradiated AuNPs in green light and subsequently functionalized with HS-PEG-NH2. The toxicity level of gold conjugates after their functionalization with DOX and TAT peptide was also evaluated. The AuNPs were prepared using the modified Turkevich method and exposed to visible light at a wavelength of 520 nm prior their PEGylation. The optical properties were analyzed by UV-vis spectroscopy, the surface modification was investigated using FTIR and XPS spectroscopies and their sizes and morphologies were evaluated by TEM and DLS techniques. DOX and TAT peptide were linked to the surface of PEGylated AuNPs by reacting their amino groups with glycidyloxypropyl of PEGylated DOX or TAT conjugates under mild conditions at room temperature and in the presence of ethanol as catalyst. The conjugates containing DOX or DOX and TAT have been characterized by fluorescence and FTIR techniques. The changes of electrochemical features were observed using cyclic voltammetry, suggesting a better stability of irradiated nanoparticles. By mass spectrometry it was confirmed that the compounds of interest were obtained. The cell viability test showed that irradiated and non-irradiated nanoparticles coated with PEG are not toxic in normal cells. Tumor cell viability analysis showed that the PEGylated nanoparticles modified with DOX and TAT peptide were more effective than pristine DOX, indicating cytotoxicity up to 10% higher than non-irradiated ones.

The effect of visible light on gold nanoparticles and some bioeffects on environmental fungi.

The oxidative stress induced by light exposed gold nanoparticles in some microorganism cells was investigated. Gold nanoparticles are currently used in biomedical and pharmaceutical research. For this study citrate-gold nanoparticles were synthesized in alkaline conditions at constant temperature of 85°C under magnetic stirring. Equal volumes of such prepared colloidal solution, were exposed to visible light at different wavelengths for 90min at room temperature. The spectra in the visible and ultraviolet range have revealed an increase in the intensity of the absorption band for gold nanoparticles exposed to light, due to the effect of surface plasmon resonance. Versatility of gold nanoparticles photocatalytic action was shown by means of manipulating wavelengths of incident light, which evidenced differences in the bioeffects induced in cellulolytic fungi - known for their environmental role but also for other applications such as in cosmetics industry. The comparative analysis of fungal response to gold nanoparticle stressors has revealed different enzyme activity and lipid peroxidation when fungi were supplied with gold nanoparticles exposed to different wavelength lights. The activity of catalase and superoxide dismutase were remarkably increased for green light exposure of gold nanoparticles suggesting fungi adaption to increased oxidative stress induced by irradiated particles; increased level of lipid peroxidation was showed by high concentration of malondialdehyde for white light exposed gold particles since antioxidant enzymes were less active.

Attenuated effects of chitosan-capped gold nanoparticles on LPS-induced toxicity in laboratory rats.

The impact of nanoparticles in medicine and biology has increased rapidly in recent years. Gold nanoparticles (AuNP) have advantageous properties such as chemical stability, high electron density and affinity to biomolecules. However, the effects of AuNP on human body after repeated administration are still unclear. Therefore, the purpose of the present study was to evaluate the effects of gold-11.68 nm (AuNP1, 9.8 µg) and gold-22.22 nm (AuNP2, 19.7 µg) nanoparticles capped with chitosan on brain and liver tissue reactivity in male Wistar rats exposed to lipopolysaccharide (LPS from Escherichia coli serotype 0111:B4, 250 µg) upon 8 daily sessions of intraperitoneal administration. Our results suggest that the smaller size of chitosan-capped AuNP shows the protective effects against LPS-induced toxicity, suggesting a very high potential for biomedical applications.

Enhanced antibacterial effect of silver nanoparticles obtained by electrochemical synthesis in poly(amide-hydroxyurethane) media.

In the present study, we report enhanced antimicrobial properties of 29 and 23 nm silver nanoparticles (Ag NPs) obtained by electrochemical synthesis in poly(amide-hydroxyurethane) media. Antibacterial activity assessed by disk diffusion method indicates that silver nanoparticles produced inhibition zones for both Escherichia coli and Staphylococcus aureus depending on silver concentration. The bacterial growth curve performed in the presence of silver nanoparticles showed a stronger antibacterial effect at lower concentrations than those described in the earlier reports. The effect was both dose and size dependent and was more pronounced against Gram negative bacteria than Gram positive one. The smallest Ag NPs used had a bactericidal effect resulting in killing E. coli cells. Scanning electron microscopy analysis indicated major damage and morphology changes of the silver nanoparticles treated bacterial cells. The major mechanism responsible for the antibacterial effect probably consists in clusters formation and nanoparticles anchorage to the bacterial cell surface.

[Difficulties in diagnostic of biliary ileus]. / Dificultati de diagnostic în ileusul biliar.

UNLABELLED: Gallstone ileus is a rare disease which can be life-threatening because of misdiagnosis preoperatively. The authors analyze the clinical observations about two women where, because of associated diseases, delayed in presentation to the hospital, volume depleted electrolyte abnormalities and, not in the last place, because of lack in accuracy of paraclinical investigations, the diagnosis was mad only intraoperatively. CONCLUSIONS: The appearance of clinical setting of high intestinal obstruction in associating with extra-kidney azotemy in female patients with gallstone in their history and no previous abdominal operations must we make to thinking about gallstone ileus.