Photophysical and photobiological studies of a silicon tribenzonaphthoporphyrazinato incorporated into liposomes for photodynamic therapy use

Nanostructured drug delivery systems (NDDS), such as liposomes, represent a growing area in biomedical research. These microheterogeneous media can be used in many biological systems to provide appropriate drug levels with a specific biodistribution. The photophysical properties of a silicon derivative of tribenzonaphthoporphyrazinato (Si-tri-PcNc) incorporated into liposome were studied by steady-state techniques, time-resolved fluorescence and laser flash photolysis. All the spectroscopy measurements performed allowed us to conclude that Si-tri-PcNc in liposome is a promising NDDS for PDT The in vitro experiments with liposomal NDDS showed that the system is not cytotoxic in darkness, but exhibits a substantial phototoxicity at 1 mu M of photosensitizer concentration and 10.0 J/cm(2) of light. These conditions are sufficient to kill about 80% of the cells.

Electrical burns: A retrospective analysis across a 5-year period

This study aims to review the experience, at an institution, with patients who suffered electrical burns and study the peculiar characteristics of this type of burn as well as its complications and epidemiological aspects. The study includes medical records of patients with electrical burns who were admitted to the Burn Unit of Hospital das Clinicas in Sao Paulo, Brazil, from November 2001 to October 2006. They were classified into four categories: high voltage (>= 1000 V), low voltage (<1000 V), `flash burn` (in which there is no electrical current flow through the body of the patient) and burns caused by lightning. The complications were more severe and common in the high-voltage group, while longer hospital stays and more complex surgical procedures due to the greater depth of burns were also observed in this group. High-voltage burns are mainly labour-/occupation-related. The majority of the patients were young men at the beginning of their professional lives. This factor generates an important socio-economic impact due to the high incidence of sequelae, resulting in amputations, rendering them unable to maintain their occupations. (C) 2009 Elsevier Ltd and ISBI. All rights reserved.

Effect of Isolated Fractions of Harpagophytum procumbens DC (Devil`s Claw) on COX-1, COX-2 Activity and Nitric Oxide Production on Whole-Blood Assay

The present study evaluates the effect of isolated fractions of Harpagophytum procumbens (devil`s claw) on cyclooxygenase (COX-1 and COX-2) activities and NO production using a whole blood assay. The activity of COX-1 was quantified as platelet thromboxane B(2) production in blood clotting and COX-2 as prostaglandin E(2) production in LPS-stimulated whole blood. Total NO(2)(-)/NO(3)(-) concentration was determined by Griess reaction in LPS stimulated blood. Assays were performed by incubation of isolated fractions obtained by flash chromatography monitored with HPLC, TLC and identified by (1)HNMR, containing different amounts of harpagoside with blood from healthy donors. Indomethacin and etoricoxib were the positive controls of COX-1 and COX-2 Inhibition. Data shows that fraction containing the highest concentration of harpagoside inhibited indistinctively COX-1 and COX-2 (37.2 and 29.5% respectively) activity and greatly inhibited NO production (66%). In contrast the fraction including iridoid pool increased COX-2 and did not alter NO and COX-1 activities. The fraction containing cinnamic acid was able to reduce only NO production (67%). Our results demonstrated that the harpagoside fraction is the main responsible for the effect of devils claw on these enzyme activities. However, other components from devil`s claw crude extract could antagonize or increase the synthesis of inflammatory mediators. Copyright (C) 2010 John Wiley & Sons, Ltd.

A method to immunolabel rodent spinal cord neurons and glia for molecular study in specific laser microdissected cells involved in neurodegenerative disorders

Neuron-glia interaction is involved in physiological function of neurons, however, recent evidences have suggested glial cells as participants in neurotoxic and neurotrophic mechanisms of neurodegenerative/neuroregenerative processes. Laser microdissection offers a unique opportunity to study molecular regulation in specific immunolabeled cell types. However, an adequate protocol to allow morphological and molecular analysis of rodent spinal cord astrocyte, microglia and motoneurons remains a big challenge. In this paper we present a quick method to immunolabel those cells in flash frozen sections to be used in molecular biology analyses after laser microdissection and pressure catapulting.

A new DTL-electrode holder for recording of electroretinograms in animals

Purpose: Contact lens electrodes (CLEs) are frequently used to register electroretinograms (ERGs) in small animals such as mice or rats. CLEs are expensive to buy or difficult to be produced individually. In addition, CLE`s have been noticed to elicit inconstant results and they carry potential to injure the cornea. Therefore, a new electrode holder was constructed based on the clinically used DTL-electrode and compared to CLEs. Material and methods: ERGs were recorded with both electrode types in nine healthy Brown-Norway rats under scotopic conditions. For low intensity responses a Naka-Rushton function was fitted and the parameters V(max), k and n were analyzed. The a-wave, b-wave and oscillatory potentials were analyzed for brighter flash intensities (1-60 scot cd s/m(2)). Repeatability was assessed for both electrode types in consecutive measurements. Results: The new electrode holder was faster in setting up than the CLE and showed lower standard deviations. No corneal alterations were observed. Slightly higher amplitudes were recorded in most of the measurements with the new electrode holder (except amplitudes induced by 60 cd s/m(2)). A Bland-Altman test showed good agreement between the DTL holder and the CLE (mean difference 35.2 mu V (Holder-CLE)). Pearson`s correlation coefficient for test-retest-reliability was r = 0.783. Conclusions: The DTL holder was superior in handling and caused far less corneal problems than the CLE and produced comparable or better electrophysiological results. The minimal production costs and the possibility of adapting the DTL holder to bigger eyes, such as for dogs or rabbits, offers with broader application prospects. (C) 2010 Elsevier B.V. All rights reserved.

INTRAVITREAL INJECTION OF AUTOLOGOUS BONE MARROW-DERIVED MONONUCLEAR CELLS FOR HEREDITARY RETINAL DYSTROPHY A Phase I Trial

Purpose: To evaluate the short-term (10 months) safety of a single intravitreal injection of autologous bone marrow-derived mononuclear cells in patients with retinitis pigmentosa or cone-rod dystrophy. Methods: A prospective, Phase I, nonrandomized, open-label study including 3 patients with retinitis pigmentosa and 2 patients with cone-rod dystrophy and an Early Treatment Diabetic Retinopathy Study best-corrected visual acuity of 20/200 or worse. Evaluations including best-corrected visual acuity, full-field electroretinography, kinetic visual field (Goldman), fluorescein and indocyanine green angiography, and optical coherence tomography were performed at baseline and 1, 7, 13, 18, 22, and 40 weeks after intravitreal injection of 10 X 10(6) autologous bone marrow-derived mononuclear cells (0.1 mL) into 1 study eye of each patient. Results: No adverse event associated with the injection was observed. A 1-line improvement in best-corrected visual acuity was measured in 4 patients 1 week after injection and was maintained throughout follow-up. Three patients showed undetectable electroretinography responses at all study visits, while 1 patient demonstrated residual responses for dark-adapted standard flash stimulus (a wave amplitude approximately 35 mu V), which remained recordable throughout follow-up, and 1 patient showed a small response (a wave amplitude approximately 20 mu V) recordable only at Weeks 7, 13, 22, and 40. Visual fields showed no reduction (with a Goldman Standard V5e stimulus) for any patient at any visit. No other changes were observed on optical coherence tomography or fluorescein and indocyanine green angiograms. Conclusion: Intravitreal injection of autologous bone marrow-derived mononuclear cells in eyes with advanced retinitis pigmentosa or cone-rod dystrophy was associated with no detectable structural or functional toxicity over a period of 10 months. Further studies are required to investigate the role, if any, of autologous bone marrow-derived mononuclear cell therapy in the management of retinal dystrophies. RETINA 31: 1207-1214, 2011

Effect of solvent hydration and temperature in the deacidification process of sunflower oil using ethanol

This work presents liquid-liquid experimental data for systems composed of sunflower seed oil, ethanol and water from 10 to 60 degrees C. The influence of process variables (temperature (T) and water concentration in the solvent (W)) on both the solvent content present in the raffinate (S(RP)) and extract (S(EP)) phases and the partition of free fatty acids (k(2)) was evaluated using the response surface methodology, where flash calculations were performed for each trial using the UNIQUAC equation. Water content in the solvent was the most important factor on the responses of S(EP) and k(2). Additionally, statistical analysis showed that the S(RP) was predominantly affected by temperature factor for low water content in the solvent. (c) 2009 Elsevier Ltd. All rights reserved.

Short-term effects of gamma ray bursts on Earth

The aim of the present work is to study the potential short-term atmospheric and biospheric influence of Gamma Ray Bursts on the Earth. We focus in the ultraviolet flash at planet`s surface, which occurs as a result of the retransmission of the gamma radiation through the atmosphere. This would be the only important short-term effect on life. We mostly consider Archean and Proterozoic eons, and for completeness we also comment on the Phanerozoic. Therefore, in our study we consider atmospheres with oxygen levels ranging from 10(-5) to 1 of the present atmospheric level, representing different moments in the oxygen rise history. Ecological consequences and some strategies to estimate their importance are outlined.

Flood Risk Assessment in Coastal Drainage Basins through a Multivariate Analysis within a GIS-Based Model

This paper presents a GIS-based multicriteria flood risk assessment and mapping approach applied to coastal drainage basins where hydrological data are not available. It involves risk to different types of possible processes: coastal inundation (storm surge), river, estuarine and flash flood, either at urban or natural areas, and fords. Based on the causes of these processes, several environmental indicators were taken to build-up the risk assessment. Geoindicators include geological-geomorphologic proprieties of Quaternary sedimentary units, water table, drainage basin morphometry, coastal dynamics, beach morphodynamics and microclimatic characteristics. Bioindicators involve coastal plain and low slope native vegetation categories and two alteration states. Anthropogenic indicators encompass land use categories properties such as: type, occupation density, urban structure type and occupation consolidation degree. The selected indicators were stored within an expert Geoenvironmental Information System developed for the State of Sao Paulo Coastal Zone (SIIGAL), which attributes were mathematically classified through deterministic approaches, in order to estimate natural susceptibilities (Sn), human-induced susceptibilities (Sa), return period of rain events (Ri), potential damages (Dp) and the risk classification (R), according to the equation R=(Sn.Sa.Ri).Dp. Thematic maps were automatically processed within the SIIGAL, in which automata cells (""geoenvironmental management units"") aggregating geological-geomorphologic and land use/native vegetation categories were the units of classification. The method has been applied to the Northern Littoral of the State of Sao Paulo (Brazil) in 32 small drainage basins, demonstrating to be very useful for coastal zone public politics, civil defense programs and flood management.

On the preparation of clean tungsten single crystals

The cleaning procedure consists of two-step-flashing: (i) cycles of low power flashes T similar to 1200 K) at an oxygen partial pressure of P(o2) = 6 x 10(-8) mbar, to remove the carbon from the surface, and (ii) a single high power flash (T similar to 2200 K), to remove the oxide layer. The removal of carbon from the surface through the chemical reaction with oxygen during low power flash cycles is monitored by thermal desorption spectroscopy. The exposure to O(2) leads to the oxidation of the W surface. Using a high power flash, the volatile W-oxides and the atomic oxygen are desorbed, leaving a clean crystal surface at the end of procedure. The method may also be used for cleaning other refractory metals like Mo, Re and It. (C) 2009 Elsevier B.V. All rights reserved.

Tryptophan photooxidation promoted by new hybrid materials prepared by condensation of naphthalene imides with silicate by the sol-gel process

Three novel hybrid organic/inorganic materials were synthesized from 4-substituted (NO(2), Br, H) 1,8-naphthalene imide-N-propyltriethoxysilane by the sol-gel process. These materials were obtained as a xerogel and partially characterized. The ability to photosensitize the oxidation and degradation of tryptophan indole ring by these materials was studied through photophysical and photochemical techniques. Although the derivatives containing Br and NO(2) as substituent do not cause efficient tryptophan photodamage, the hybrid material obtained from 1,8-naphthalic anhydride is very efficient to promote tryptophan photooxidation. By using laser flash photolysis it was possible to verify the presence of naphthalene imide transient radical species. The presence of oxygen causes an increase of the yield of radical formation. These results suggest that the mechanism of photodegradation of tryptophan occurs by type I, i.e. the transient radical (TrpH(center dot+)) formed by the direct reaction of the triplet state of the naphthalene imide moiety with tryptophan. Thus a inorganic-organic hybrid material that can be used to promote the oxidation of biomolecules was obtained. (C) 2009 Elsevier B.V. All rights reserved.

Quenching of excited states of red-pigment zinc protoporphyrin IX by hemin and natural reductors in dry-cured hams

Zinc protoporphyrin IX (ZnPP), the major red pigment in hams dry-cured without nitrates/nitrites, is an efficient photosensitizer, which upon absorption of visible light forms short-lived excited singlet state ((1)ZnPP*) and by intersystem crossing yields the very reactive triplet-excited state ((3)ZnPP*). Using nano-second laser flash photolysis and transient absorption spectroscopy NADH, ascorbic acid, hemin and dehydroascorbic acid were each found to be efficient quenchers of (3)ZnPP*. The deactivation followed, in homogeneous dimethyl sulfoxide (DMSO) or DMSO:water (1:1) solutions, second-order kinetics. The rate constant for ascorbic acid and NADH for reductive quenching of (3)ZnPP* was at 25 A degrees C found to be 7.5 +/- A 0.1 x 10(4) L mol(-1) s(-1) and 6.3 +/- A 0.1 x 10(5) L mol(-1) s(-1), respectively. The polyphenols catechin and quercetin had no effect on (3)ZnPP*. The quenching rate constant for oxidative deactivation of (3)ZnPP* by dehydroascorbic acid and hemin was at 25 A degrees C: 1.6 +/- A 0.1 x 10(5) L mol(-1) s(-1) and 1.47 +/- A 0.1 x 10(9) L mol(-1) s(-1), respectively. Oxidized glutathione did not act as an oxidative quencher for (3)ZnPP*. After photoexcitation of ZnPP to (1)ZnPP*, fluorescence was only found to be quenched by the presence of hemin in a diffusion-controlled reaction. The efficient deactivation of (3)ZnPP* and (1)ZnPP* by the metalloporphyrin (hemin) naturally present in meat may accordingly inherently protect meat proteins and lipids against ZnPP photosensitized oxidation.

Light-Induced Oxidation of Unsaturated Lipids as Sensitized by Flavins

Triplet-excited riboflavin ((3)RF*) was found by laser flash photolysis to be quenched by polyunsaturated fatty acid methyl esters in tert-butanol/water (7:3, v/v) in a second-order reaction with k similar to 3.0 x 10(5) L mol(-1) s(-1) at 25 degrees C for methyl linoleate and 3.1 x 10(6) L mol(-1) s(-1), with Delta H double dagger = 22.6 kJ mol(-1) and Delta S double dagger = -62.3 J K(-1) mol(-1), for methyl linolenate in acetonitrile/water (8:2, v/v). For methyl oleate, k was <10(4) L mol(-1) s(-1). For comparison, beta-casein was found to have a rate constant k similar to 4.9 x 10(8) L mol(-1) s(-1). Singlet-excited flavin was not quenched by the esters as evidenced by insensitivity of steady-state fluorescence to their presence. Density functional theory (DFT) calculations showed that electron transfer from unsaturated fatty acid esters to triplet-excited flavins is endergonic, while a formal hydrogen atom transfer is exergonic (Delta G(HAT)degrees = -114.3, -151.2, and -151.2 kJ mol(-1) for oleate, linoleate, and linolenate, respectively, in acetonitrile). The reaction is driven by acidity of the lipid cation radical for which a pK(a) similar to -0.12 was estimated by DFT calculations. Absence of electrochemical activity in acetonitrile during cyclic voltammetry up to 2.0 V versus NHE confirmed that Delta G(ET)degrees > 0 for electron transfer. Interaction of methyl esters with (3)RF* is considered as initiation of the radical chain, which is subsequently propagated by combination reactions with residual oxygen. In this respect, carbon-centered and alkoxyl radicals were detected using the spin trapping technique in combination with electron paramagnetic resonance spectroscopy. Moreover, quenching of 3RF* yields, directly or indirectly, radical species which are capable of initiating oxidation in unsaturated fatty acid methyl esters. Still, deactivation of triplet-excited flavins by lipid derivatives was slower than by proteins (factor up to 10(4)), which react preferentially by electron transfer. Depending on the reaction environment in biological systems (including food), protein radicals are expected to interfere in the mechanism of light-induced lipid oxidation.