Ultraviolet-C light for treatment of Candida albicans burn infection in mice

Burn patients are at high risk of invasive fungal infections, which are a leading cause of morbidity, mortality, and related expense exacerbated by the emergence of drug resistant fungal strains. In this study, we investigated the use of UVC light (254 nm) for the treatment of yeast Candida albicans infection in mouse third degree burns. In vitro studies demonstrated that UVC could selectively kill the pathogenic C. albicans compared with a normal mouse keratinocyte cell line in a light exposure dependent manner. A mouse model of chronic C. albicans infection in non-lethal third degree burns was developed. The C. albicans strain was stably transformed with a version of the Gaussia princeps luciferase gene that allowed real-time bioluminescence imaging of the progression of C. albicans infection. UVC treatment with a single exposure carried out on day 0 (30 min postinfection) gave an average 2.16-log(10)-unit (99.2%) loss of fungal luminescence when 2.92 J cm(-2) UVC had been delivered, while UVC 24 h postinfection gave 1.94-log(10)-unit (95.8%) reduction of fungal luminescence after 6.48 J cm(-2). Statistical analysis demonstrated that UVC treatment carried out on both day 0 and day 1 significantly reduced the fungal bioburden of infected burns. UVC was found to be superior to a topical antifungal drug, nystatin cream. UVC was tested on normal mouse skin and no gross damage was observed 24 h after 6.48 J cm(-2). DNA lesions (cyclobutane pyrimidine dimers) were observed by immunofluorescence in normal mouse skin immediately after a 6.48 J cm(-2) UVC exposure, but the lesions were extensively repaired at 24 h after UVC exposure.     

Nanostructuring carbon fibre probes for use in central venous catheters

A carbon fibre probe is described which utilises the oxidation of an endogenous biomarker to provide diagnostic information on the condition of intravascular access lines. The probe surface was modified through anodic oxidation to provide a high selectivity towards urate which was used as a redox probe through which the pH could be determined. A Nernstian response (−60 mV/pH) was obtained which was free from the interference of other redox species common to biofluids. The electroanalytical performance of the probe has been optimised and the applicability of the approach demonstrated through testing the responses in whole blood.     

Acetylation of the HIV-1 Tat protein: an in vitro study

In the last few years, the understanding of lysine acetylation as a regulatory post-translational modification of proteins in cell signalling cascades has increased. It is now known that not only histones but also non-histone factors can serve as substrates of different acetyltransferase enzymes. Acetylated lysine residues in non-histone factors are often identified using radioactive labelling experiments and immunochemical analysis of synthetic peptides. In this study of the human immunodeficiency virus 1 (HIV-1) Tat protein, we demonstrate the benefits of matrix-assisted laser desorption/ionisation mass spectrometry, proteolytic digestion and Edman sequencing for the mapping of acetylation sites. We confirmed that the HIV-1 Tat protein is acetylated in vitro by the acetyltransferase p300 at a specific lysine residue at position 50 in its RNA binding region. Furthermore, we showed that the Tat cysteine-rich region is acetylated at multiple cysteine residues in the absence of enzyme. Since this non-enzymatic cysteine acetylation occurs independently from the surrounding peptide sequence, we consider the presence of cysteine residues in acetylated peptides an important factor for the interpretation of in vitro acetylation assays in general.Abbreviations aa Amino acid - AcCoA Acetyl coenzyme A - acm Acetamidomethyl - ARM Arginine-rich motif - CRR Cysteine-rich region - HAT Histone acetyltransferaseThis article is dedicated to Harald zur Hausen on the occasion of his retirement as head of the German Cancer Research Center (Deutsches Krebsforschungszentrum) with gratitude and appreciation for 20 years of leadership     

Temperature dynamics of magnetoactive compounds under terahertz irradiation: characterization by an EPR study

A possibility of fast rapid temperature changing for the studied compound makes it possible to study related phenomena, such as thermally induced trapping of metastable states in magnetoactive compounds and thermally activated catalytic and biological processes. The Electron Paramagnetic Resonance (EPR) spectroscopy station at the Novosibirsk Free Electron Laser (NovoFEL) allows one to study effects of powerful terahertz (THz) radiation on the spin state of paramagnetic systems. A change in the sample temperature as a result of radiation absorption is an inevitable consequence of such an exposure. However, the sample heating at the NovoFEL EPR station itself is of interest due to the record power of THz radiation and small sizes of the samples used. A combination of these two factors can provide a significantly high heating rate. The magnetoactive complex [Cu(hfac)₂L^Et] was chosen as a model system for studying the heating process, since the complex has a magnetostructural transition at ～125 K with substantially different spin states above and below the transition temperature. The heating processes with the amplitudes above 60 K were studied, the heating and cooling rates of the sample in similar experiments were estimated, and prospects for using the method to study various thermally induced effects are discussed.

     

Photon energy limits for food irradiation: a feasibility study

The penetrating nature of the photons produced by the X-ray (bremsstrahlung) process makes them attractive for the treatment of dense materials in industrial radiation processing. The inefficiency of the conversion process can be balanced by the exposure of high Z materials to electrons with high energy. However, activation of the product being irradiated and the equipment imposes energy limits. Results of a theoretical and experimental study to investigate the key parameters have resulted in recommendations for the design of X-ray converters in the electron energy range 7 to 11 MeV. Results of the Monte Carlo calculations and the methods used in conversion experiments with the 50 kW IMPELA accelerator are reported.     

Spermicidal activity of the hexane extract of Piper longum: an in vitro study

This study was carried out to assess the spermicidal action of hexane extract from the fruits of Piper longum Linn. The sperm immobilisation studies showed that 20 mg/mL of hexane extract was able to immobilise sperms completely within 20 s. The sperm revival test revealed that the effects were spermicidal as sperm immobilisation effect was irreversible. There was also a significant reduction in sperm viability in the treated group in comparison to the control. The hypo-osmotic swelling of these sperms was significantly reduced, indicating that the hexane extract may probably cause injury to the sperm plasma membrane. Hence, this study showed that the hexane extract of P. longum possesses potential contraceptive spermicidal activity in vitro.     

Selectivity under microwave irradiation. Benzylation of 2-pyridone: an experimental and theoretical study

The reaction of 2-pyridone with benzyl bromide in the absence of base and under solvent-free conditions has been studied experimentally and by computational methods. This reaction was one of the first reported examples in which modification of selectivity under microwave irradiation was observed. C- and/or N-alkylations were obtained depending on the benzyl halide and the heating system. N-Alkylation through mechanism A (S_N2 mechanism) is kinetically favoured while C-alkylation through an S_N1-type mechanism is thermodynamically favoured and is observed under microwave irradiation. Two S_N1-type mechanisms (mechanisms B and C) have been calculated, mechanism C being a kind of S_Ni. The influence of the pyridone/benzyl bromide ratio was studied. A second molecule of pyridone stabilizes the transition state and assists the leaving of the bromide ion. The occurrence of C-alkylation under microwave irradiation is explained by the predominance of the thermodynamic control in these conditions. Under microwave irradiation N-alkylation through an S_N1-type mechanism (mechanism C) can also occur. The dependence of the outcome of N-alkylation on the benzyl bromide ratio has been explained by a shift in the mechanism from S_N2 to S_N1 under microwave irradiation. Computational calculations have shown to be a useful tool for determination of the origin of the selectivity under microwave irradiation.     

Hydrogels coupled with self-assembled monolayers: an in vitro matrix to study calcite biomineralization

This paper describes the control of the nucleation and growth of calcite crystals by a matrix composed of an agarose hydrogel on top of a carboxylate-terminated self-assembled monolayer (SAM). The design of this matrix is based upon examples from biomineralization in which hydrogels are coupled with functionalized, organic surfaces to control, simultaneously, crystal morphology and orientation. In the synthetic system, calcite crystals nucleate from the (012) plane (the same plane that is observed in solution growth). The aspect ratio (length/width) of the crystals decreases from 2.1 +/- 0.22 in solution to 1.2 +/- 0.04 in a 3 w/v % agarose gel. One possible explanation for the change in morphology is the incorporation of gel fibers inside of the crystals during the growth process. Etching of the gel-grown crystals with deionized water reveals an interpenetrating network of gel fibers and crystalline material. This work begins to provide insight into why organisms use hydrogels to control the growth of crystals.     

Zinc and copper oxide nanoparticles decrease synaptosomal glutamate uptake: an in vitro study

Nanoparticles (NPs) are considered as an important environmental risk factor for cognitive impairments and neurodegenerative disorders. Recent evidences have reported a glutamatergic system response against air-borne NPs. Zinc and copper oxides (ZnO and CuO) NPs are the most common metal oxide NPs in industries. The effects of these NPs on hippocampal voltage-dependent ion channels and spatial cognition have been previously studied. However, there is a lack of evidence regarding the effects of ZnO and CuO NPs on glutamatergic synapse neurotransmission in central nervous system. In the present study, the effects of ZnO and CuO NPs on glutamate (Glu) release and uptake have been investigated in isolated nerve terminals (synaptosomes). Our findings have shown that, even in high doses of ZnO and CuO NPs, no significant effect on Glu release is observed. However, a decrease has been observed in uptake of Glu. Hence, ZnO and CuO NPs can be considered as hazardous agents inducing neurodegenerative disorders through Glu excitotoxicity.     

Electrospun cellulose acetate wound dressings loaded with Pramipexole for diabetic wound healing: an in vitro and in vivo study

In the current study, a Pramipexole-loaded wound dressing was produced via electrospinning of cellulose acetate solution. Pramipexole was added to cellulose acetate solution at 3, 5, and 10% w/w concentrations and then electrospun. The produced wound dressings were studied regarding their physicochemical and biological properties. Results of cell viability assay and cytoprotection studies showed that cellulose acetate wound dressings containing 3% w/w Pramipexole had significantly higher cell viability compared with other concentrations. The wound healing potential of dressings incorporated with 3% drug was studied in a rat model of diabetic wound. Study showed that the cellulose acetate/3% Pramipexole scaffolds had significantly higher percentage of wound closure, epithelial thickness, and collagen deposition compared with drug-free dressings and control group. Gene expression study showed that the drug-loaded wound dressings could reduce oxidative stress and alleviate inflammation at significantly higher extent compared with other groups.

     

A comparative study of 632.8 and 532 nm laser irradiation on some rheological factors in human blood in vitro

The effects of laser irradiation with 632.8 and 532 nm on rheological properties of blood were comparatively studied in vitro. Under the irradiation condition of 30 mW, laser irradiation of blood samples using a spot diameter of 5 mm with each laser, showed promising results in the modulation of hemorheological properties. When blood samples from patients with abnormally high values of erythrocyte sedimentation rate (ESR) were irradiated, the values of ESR were lowered statistically by either of the 632.8 or 532 nm lasers. The laser irradiation reduced blood viscosities at different shear rates (10-110 S(-1)) for the hyper-viscosity blood samples. Laser irradiation increased the electrophoretic mobility (EPM) of erythrocytes when the values of the sample's EPM were abnormally slow. The erythrocyte deformability was enhanced by laser irradiation when the deformability of the sample from the patients was originally poor. For verifying the improvement of laser irradiation on erythrocyte deformability, the typical erythrocyte samples with poor deformability were produced by the pre-treatment of the erythrocytes with Ca(2+). The deformability of these erythrocyte samples was also improved after laser irradiation. These results suggest that membrane-bound hemoglobin (Hbm) might be the initial site of the interaction, since Hbm is the main cause of poor deformability when erythrocytes were treated with Ca(2+). In all experiments including ESR, blood viscosity, EPM and erythrocyte deformability, the 532 nm laser demonstrated more efficient effects on modulating rheological properties than 632.8 nm laser. This wavelength effect is consistent with the absorption spectrum of hemoglobin, reflecting that hemoglobin may be one of the action targets under laser irradiation.     

Phototoxic effect of visible light on Porphyromonas gingivalis and Fusobacterium nucleatum: an in vitro study

The antibacterial effect of visible light irradiation combined with photosensitizers has been reported. The objective of this was to test the effect of visible light irradiation without photosensitizers on the viability of oral microorganisms. Strains of Porphyromonas gingivalis, Fusobacterium nucleatum, Streptococcus mutans and Streptococcus faecalis in suspension or grown on agar were exposed to visible light at wavelengths of 400-500 nm. These wavelengths are used to photopolymerize composite resins widely used for dental restoration. Three photocuring light sources, quartz-tungsten-halogen lamp, light-emitting diode and plasma-arc, at power densities between 260 and 1300 mW/cm2 were used for up to 3 min. Bacterial samples were also exposed to a near-infrared diode laser (wavelength, 830 nm), using identical irradiation parameters for comparison. The results show that blue light sources exert a phototoxic effect on P. gingivalis and F. nucleatum. The minimal inhibitory dose for P. gingivalis and F. nucleatum was 16-62 J/cm2, a value significantly lower than that for S. mutans and S. faecalis (159-212 J/cm2). Near-infrared diode laser irradiation did not affect any of the bacteria tested. Our results suggest that visible light sources without exogenous photosensitizers have a phototoxic effect mainly on Gram-negative periodontal pathogens.     

Modifications of in vitro skin penetration under solar irradiation: evaluation on flow-through diffusion cells

The effect of solar irradiation on ex vivo dermatomed hairless rat skin samples maintained in culture on flow-through diffusion cells for at least 24 h was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay and by histological observations. Transepidermal water loss (TEWL) measurements and kinetic analysis of the permeation of both tritiated water and 14C caffeine through the skin were performed after full-spectrum solar exposure involving the use of a xenon arc solar simulator. After a UV exposure of less than 420 mJ/cm2, skin integrity and permeation of both water and caffeine did not change significantly. In contrast, after a 420 mJ/cm2 UV exposure, the epidermis appeared more contracted, associated with an increase of 55% of TEWL and 220% of the skin permeation of tritiated water after 6 h. The data suggested a dramatic alteration of the skin barrier integrity. Moreover, the flux of 14C caffeine increased rapidly by 338% of the absorption of water 12 h after irradiation. These results reveal the presence of a threshold UV exposure that would not modify skin penetration.     

Fabrication and characterization of an irradiation facility for large-sample geometry

An irradiation facility consisting of a modified beam port shielding plug has been designed, fabricated built and characterized for use in irradiating non-standard sample geometries. The shielding plug features a graphite moderator at the core end with a hole, or “well” drilled of sufficient diameter and depth to accommodate an eight ounce (227 gram) sample bottle. Added shielding behind the graphite consists of castable neutron- and -gamma-ray shielding. The modified shielding plug can be removed relatively quickly from its irradiation position to minimize personnel exposures. It is mounted in close proximity to the Ohio State University Research Reactor reactor core to allow performance of high-sensitivity neutron activation analysis studies. Using the SAND-II unfolding code, the energy-dependent neutron flux has been measured in the sample irradiation position. When operating at 100 % power, the total flux is 3.9 × 10¹² n/cm²/s. Of this, 55 % is thermal (<0.5 eV), 23 % is epithermal (>0.5 eV, <0.5 MeV), and 22 % is “fast” (>0.5 MeV). This makes the facility suitable for neutron activation studies. Recently it has been used for irradiation of filter papers collected in a study of particulate air pollution in the form of atmospheric particulate matter in an urban environment.     

Antibacterial activity of tetraaryl-porphyrin photosensitizers: an in vitro study on Gram negative and Gram positive bacteria

BACKGROUND: Photodynamic therapy exploits visible light and photosensitizers to inactivate cells and this methodology is currently used for the treatment of several types of malignancy. Although various tumours are successfully treated with PSs and light, the application on microorganisms (photodynamic antimicrobial chemotherapy) has not yet found specific medical applications and still remains an open field of fundamental research. PURPOSE: The assessment of the effect of a panel of seven tetraaryl-porphyrins, two commercial (PS 1 and 2) and five synthetic (PS 3-7) in in vitro experiments against Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus. METHODS: Three of the new photosensitizers (PS 3, 4 and 5) are tetracationic porphyrins and were prepared by N-alkylation of 5,10,15,20-tetra-4-pyridylporphyrin with a large excess of different benzyl chlorides; compound 7 is a dicationic porphyrin and was obtained in a similar way using a lower excess of 4-methoxybenzyl chloride. The neutral porphyrin (PS 6) was previously described. Dose-response curves were obtained titrating the survivors of cell suspensions (10(8)cfu/ml) exposed to the PSs and irradiated with visible light (total fluence rate 266 J/cm2). RESULTS: The non ionic porphyrin 6 was the least active PS against all the tested bacteria. Cationic PSs 3, 4, 5 and 7 were more active than the commercial 1 and 2. The Gram positive S. aureus was more sensitive to all the PSs than the Gram negative E. coli and P. aeruginosa, the latter being the more resistant one. Compound 7 was found particularly efficient against P. aeruginosa, causing a 7 log units reduction of survivors at a concentration of 8 microM. CONCLUSIONS: The reported results confirm that the presence of positively charged groups on porphyrin frame is fundamental for PSs antibacterial activity, however our data suggest that a moderate degree of lipophilicity, achievable by the introduction of aromatic hydrocarbon side chains on the pyridyl moieties, may improve PSs efficiency. Furthermore dicationic porphyrin 7 seems to be more efficient than the corresponding tetracationic derivatives thus emphasizing an interesting feature involved in the PSs activity.     

Effects of UV irradiation on skin and nonskin-associated herpes simplex virus infections in rats

Herpes simplex virus (HSV) normally causes vescular lesions on mucocutaneous surfaces but can also cause encephalitis. The virus can reactivate from the latent state in neurons to form recrudescent lesions. One common stimulus for reactivation is exposure to sunlight. In the present study, the effects of irradiating rats with suberythemal ultraviolet (UV) before or after infecting them epidermally with HSV was investigated. Preexposure to UV impaired HSV-specific cellular immune responses, as indicated by delayed type hypersensitivity (DTH) and in vitro lymphoproliferation assays. However, the number and severity of the skin lesions were not altered. In contrast, exposure after infection did not affect cellular immunity but resulted in a large increase in the severity and number of lesions. In a second series of experiments, the effects of preirradiating with UV on HSV infection was examined using a route of inoculation which was not skin-associated, namely intranasal, allowing direct non-invasive access to the nervous system. It was found that suppressed DTH resulted, together with an increase in the incidence and severity of neurological symptoms and an increased viral load in the brain. Therefore, unlike the situation in the skin, irradiation of rats before intranasal inoculation led to a suppressed immune response to HSV which correlated with increased viral load and symptoms. These results indicate that the effects of UV may be dependent on whether the animal is exposed before or after the infection, and whether the infection is skin-associated or systemic.     

Development of an up-flow irradiation device for electron beam wastewater treatment

Electron beam irradiation processing is an available technology to treat sludge, groundwater, surface water and industrial and municipal wastewater. The use of this technology into environmental areas has moved slowly because industry and government are always conservative in the adoption of new processes, especially when they can not observe the efficiency and cost effectiveness of a treatment in a full scale facility.

In this direction the hydraulic system where the water is presented to the electron beam governs the efficacy of this technology. The present work is based on the development of the irradiation device, an up-flow delivery system that alleviates the dependence of energy transfer to the stream with the beam accelerating voltage (penetration capability).

In this work a series of experiments were performed to establish the relationships between accelerating voltage ranging from 0.5 to 1.5 MeV, current, water flow and deposited dose in order to optimize the operating parameters and the selection of a cost-effective commercial electron beam.     

Repurposing homeopathic drug Lachesis 200C as an anticancer activity: In vitro and in ovo study

Cancer is one of the most critical health burdens with leading causes of death worldwide. Homeopathy is one of the complementary and alternative therapies, which utilizes venoms and toxins in ultra-high dilutions for therapeutics. In the present investigation, we used the homeopathy Lachesis 200C drug to study anticancer activity on the mouse fibroblast cells [L929], human prostate cancer cells [PC3], and in chick embryo model. Treating with Lachesis 200C showed 91.10% and 37.47% reduction in cell viability in L929 and PC3 respectively as compared to control by MTT assay. In the chick embryo model Lachesis 200C (dose of 50% and 100%) treatment resulted in antiangiogenic activity as compared to the control group. There was an antiproliferative and cytotoxic activity of Lachesis 200C in PC3 and L929 ​cell lines. Lachesis 200C inhibited the growth of PC3 cells. In the in vivo studies, Lachesis 200C treated chicks showed a significant decrease in or complete disappearance of blood vessels from chorioallantoic membrane (CAM) areas compared to control. The findings indicate that the level of angiogenesis was dramatically decreased by Lachesis 200C. Lachesis 200C showed the potential to act as an anticancer agent. Further studies with Lachesis200 could lead to a potential anticancer agent.     

A study of irradiation in the treatment of wastewater

A grafting copolymer of starch and acrylamide was prepared by ⁶⁰Co-γ pre-irradiation. After purification, the copolymer was modified by a cationic reaction to form a cationic copolymer. The structure of the cationic copolymer was identified by IR and NMR spectroscopy. Using the industrial and sanitary municipal wastewater from the Factory of Wastewater Treatment of Gaobeidian in Beijing as the study sample, three-treatment methods: flocculation deposition, flocculation deposition combined with γ irradiation and the direct irradiation were carried out. COD was applied to evaluate the treatment effect. The preliminary results show that the method of flocculation deposition combined with γ irradiation was effective than the other two.     

Bactericidal performance of photocatalytic titanium dioxide particle mixture under ultraviolet and fluorescent light: an in vitro study

When ultraviolet (UV) light comes into contact with titanium dioxide (TiO₂), a variety of free radicals are released to provide a potent oxidizing power. Few reports are available, however, evaluating the bactericidal effects of TiO₂ particle under UV light and fluorescent light (FL) in the same line of research for clinical applications. In the present study, we set out to evaluate the in vitro photocatalytic bactericidal effects on Staphylococcus aureus, which is one of the most common pathogens of infectious disease, in an aqueous system of TiO₂ particles irradiated by UV and FL. A TiO₂ particle mixture containing 0.019 mg/ml of TiO₂ was prepared. A bacterial solution was added dropwise to the mixture, and the resulting product was irradiated by UV or FL light. The colony‐forming units were counted and the bacterial survival rate was calculated. Control samples maintained a relatively high bacterial survival rate. In the TiO₂ mixture group, however, the bacterial survival rate decreased steadily, reaching 9.4% after 60 min of exposure to UV light and 10.9% after 60 min of FL irradiation. Distributing the TiO₂ particles in a water mixture produces highly efficient light absorption and enables greater and more frequent adhesion with bacteria, allowing a high degree of photocatalytic antibacterial action. Although the quantity was inferior to UV, our TiO₂ particles were able to show effective bactericidal activity even under FL. The TiO₂ particle mixture is expected to prove effective in preventing postoperative infection. Copyright © 2009 John Wiley & Sons, Ltd.