Purification of lipopeptide biosurfactant extracts obtained from a complex residual food stream using Tricine-SDS-PAGE electrophoresis

Protocols to identify lipopeptide biosurfactant extracts contained in complex residual streams are very important, as fermented agri-food matrices are potential sources of these valuable compounds. For instance, corn steep liquor (CSL), a secondary stream of the corn wet-milling industry, is composed of a mixture of microbial metabolites, produced during the corn steeping process, and other natural metabolites released from corn, that can interfere with the purification and analysis of lipopeptides. Electrophoresis could be an interesting technique for the purification and further characterization of lipopeptide biosurfactant extracts contained in secondary residual streams like CSL, but there is little existing literature about it. It is necessary to consider that lipopeptide biosurfactants, like Surfactin, usually are substances that are poorly soluble in water at acidic or neutral pH, forming micelles what can inhibit their separation by electrophoresis. In this work, two lipopeptide biosurfactant extracts obtained directly from CSL, after liquid-liquid extraction with chloroform or ethyl acetate, were purified by applying a second liquid extraction with ethanol. Following that, ethanolic biosurfactant extracts were subjected to electrophoresis under different conditions. Lipopeptides on Tricine-SDS-PAGE (polyacrylamide gels) were better visualized and identified by fluorescence using SYPRO Ruby dye than using Coomassie blue dye. The matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) analysis of lipopeptide isoforms separated by electrophoresis revealed the presence of masses at 1,044, 1,058, and 1,074 m/z, concluding that Tricine-SDS-PAGE electrophoresis combined with MALDI-TOF-MS could be a useful tool for purifying and identifying lipopeptides in complex matrices.

Solubilization of cuprous oxide in water using biosurfactant extracts from corn steep liquor: a comparative study

In this work the chemical characterization (elemental analysis and the content of phospholipids) and surface-active properties of two biosurfactants (BS) extracted with both chloroform or ethyl acetate from corn steep liquor were compared. The phospholipids content for the BS extracted with chloroform (BS1) was considerably higher (8.15%) than that obtained for the BS extracted with ethyl acetate (BS2), 0.11%. When comparing the FTIR spectra of the two BS studied in this work with the spectrum of the commercial surfactant lecithin, a greater similarity (75%) was observed with the spectrum of the BS1. The biosurfactant extract (BS2) provided the most favorable conditions for the solubilization of cuprous oxide (Cu-Ox) in water (12.54% of copper dissolved), in comparison with BS1. The results achieved were considerably better than those obtained with chemical surfactants (Tween 80, SDS and CTAB) on solubilizing Cu-Ox, resulting in the latter cases on percentages of Cu dissolved always lower than 0.21%. In addition, a factorial design was performed obtaining the optimum conditions to solubilize Cu-Ox, where the maximum water solubility of Cu-Ox (13.17%) was achieved using 3.93 g/L of BS2 with a contact time of 19.86 min and using a concentration of Cu-Ox of 1.96 g/L. Thus, the BS2 extract could have a promising future as solubilizing agent in the formulation of more sustainable Cu-Ox based pesticides. Moreover, it was confirmed that the presence of phospholipids prevents the solubilization of copper-based pesticides in water.

Enfermedad podal en bovinos: prevalencia y asociación con algunas variables

La enfermedad podal constituye uno de los síndromes más difíciles de controlar en la industria lechera. El presente estudio tuvo como objetivo cuantificar la prevalencia de enfermedad podal, evaluando su asociación con factores como raza, orden de parto y peso. Se trata de un estudio retrospectivo que utiliza los registros sanitarios y productivos de un hato lechero ubicado en el trópico alto de Colombia. Los componentes raciales presentes fueron F1 Holstein × Blanco Orejinegro, 3/4 Holstein 1/4 Blanco Orejine- gro, 5/8 Holstein 3/8 Blanco Orejinegro y Holstein 100%. Se consideraron 6 órdenes de parto. La variable enfermedad podal presenta una distribución binomial. El efecto de los factores se verificó utilizando un modelo lineal generalizado, por medio de una regresión logística (PROC GENMOD, sas versión 9.4). En caso de existir diferencias significativas, se aplicó el procedimiento LSMEANS del sas (versión 9.4) y un Odds Rattio entre los niveles que presentaron significancia. La prevalencia de enfermedad podal en el hato fue de 10,55%. Los factores de riesgo considerados fueron estadísticamente significativos: componente racial (p < 0,0009), orden parto (p < 0,0001) y peso medio de las vacas (p < 0,0001). Se observó un incremento en la prevalencia de la enfermedad asociado a la raza Holstein, orden de parto alto y bajo peso corporal. La prevalencia de enfermedad podal fue mayor en vacas Holstein puras y menor en vacas Holstein cruzadas con Blanco Orejinegro, debido a la resistencia por heterosis que la raza criolla aporta. El incremento del orden de parto al igual que el bajo peso se relacionan con una mayor prevalencia de esta enfermedad.

First passage of an active particle in the presence of passive crowders

We experimentally study the stochastic transport of a self-propelled camphor boat, driven by Marangoni forces, through a crowd of passive paper discs floating on water. We analyze the statistics of the first passage times of the active particle to travel from the center of a circular container to its boundary. While the mean times rise monotonically as a function of the covered area fraction φ of the passive paper discs, their fluctuations show a non-monotonic behavior - being higher at low and high value of φ compared to intermediate values. The reason is traced to an interplay of two distinct sources of fluctuations - one intrinsic to the dynamics, while the other due to the crowding.

Stochastic resonance via parametric adaptation: Experiments and numerics

In contrast with the conventionally observed mechanism of stochastic resonance (SR) wherein the level of additive noise is systematically varied with a fixed set-point parameter, in this work we report the emergence of the SR phenomena in an electrochemical system maintaining the same level of noise and varying the parametric distance from a homoclinic bifurcation inherent to the system. The experimental system involves the corrosion of a metal disk in an acidic medium under potentiostatic conditions. The applied potential is used as a control parameter and the anodic current generated during the electrodissolution of the metal is the accessible system variable. In the presence of noise, it was observed that the system was able to enhance its output's fidelity with a weak subthreshold input signal when the set point was kept at an optimal parametric distance from the bifurcation. Numerical simulations were performed on a model for this system to corroborate the experimental observations. This type of SR may be critical in scenarios where a biological entity has control only on its sensory parameters and not on the environmental noise amplitude.

Technical approaches to evaluate the surfactant-enhanced biodegradation of biodiesel and vegetable oils

This research compared the effects of biosurfactant on the biodegradation of biodiesel and vegetable oils while validating two conceptually diverging methodologies. The two experimental setups were successfully modeled towards the effects of biosurfactants during biodegradation. We established the equivalence of both methodologies from the data output. As expected, the biosurfactants caused an increased oil uptake, thus increasing biodegradation performance. Cooking oils were favored by the microbial consortium as a carbon source when compared with biodiesel fuel, especially after use in food preparation. However, we found that biodiesel substrate standout with the highest biodegradation rates. Our results might indicate that a rapid metabolic change from the original compound initially favored biodiesels during the assimilation of organic carbon for a set specialized microbial inoculum. The data output was successfully combined with mathematical models and statistical tools to describe and predict the actual environmental behavior of biodiesel and vegetable oils. The models confirmed and predicted the biodegradation effectiveness with biosurfactants and estimated the required timeframe to achieve satisfactory contaminant removal.

Pattern selection and regulation using noise in a liquid metal

Electric forcing can be used to select and to regulate the shape of liquid metals. In this work, we present a transition among different patterns in a liquid mercury drop regulated by noise. A stochastic resonancelike phenomenon was observed for two different structural transitions of the liquid metal. In the first set of experiments, the transition from irregular (I) → triangular (T) → irregular (I) patterns was obtained by increasing the amplitude of biased white noise. In the second part, we observed the transition from irregular (I) → elliptical (E) → irregular (I) patterns using the same kind of noise. Periodic stochastic resonance was corroborated in our experiments by employing the cross-correlation coefficient technique.

Evaluation of a biosurfactant extract obtained from corn for dermal application

At present, there is an increasing demand to improve the sustainability of surface-active compounds in dermal formulations. Biosurfactants, which are derived from living cells, are considered to be more environmentally friendly than synthetic surfactants. Thus, the use of biosurfactants is a promising strategy for the formulation of more environmentally friendly and sustainable dermal products. In this work, a biosurfactant extract (BS) obtained from corn wet-milling industry was studied for its potential use in dermal formulations. The corn derived BS possesses good surface-active properties and was found to be a suitable co-stabilizer for nanoemulsions and nanocrystals for dermal application. It also possesses antioxidative and skin protective properties and was also able to increase the dermal penetration efficacy for lipophilic actives. In dermal formulations the BS can therefore be used as co-stabilizer with antioxidative and penetration enhancing properties at the same time.

Study of the synergic effect between mica and biosurfactant to stabilize Pickering emulsions containing Vitamin E using a triangular design

HYPOTHESIS

Vitamin E has interesting biological functions for the cosmetic and pharmaceutical industry because it can act as a fat-soluble antioxidant, as well as peroxyl radical scavenger. However, this vitamin is formed by a group of compounds that include tocopherols (γ-tocopherols, α-tocopherol) characterized by their poor solubility in water, what implies the need of using stabilizing agents such as biosurfactants or minerals, in order to make them soluble or stable in formulations composed by water and oil.

EXPERIMENTS

In this work, it has been evaluated the synergic effect between a mining silicate mineral (mica) and a biosurfactant extract, obtained from corn steep liquor, to stabilize emulsions containing water and a non-aqueous soluble antioxidant consisting of Vitamin E, through the use of a triangular design.

FINDINGS

The results show that the presence of biosurfactant extract improves the emulsion volume up to 70% after 22 days, for an emulsion composed of Vitamin E and biosurfactant, whereas the mica component was able to increase the emulsion stability until values of 80% after 30 days of experiment, for those emulsions containing 10% of mica. Hence, both novel ingredients produce a synergistic effect on the Pickering emulsions carried out in the study.

Bioactivity of glycolipopeptide cell-bound biosurfactants against skin pathogens

The antimicrobial and anti-adhesive activities of the cell-bound biosurfactants, produced by Lactobacillus pentosus (PEB), characterized as glycolipopeptide macromolecules, were evaluated against several microorganisms present in the skin microflora, envisaging its potential use as a "natural" ingredient in cosmetic and personal care formulations. Their performance was compared with another cell-bound biosurfactants also characterized as glycolipopeptides produced by Lactobacillus paracasei (PAB). At concentrations of 50mg/mL, the PEB showed an important antimicrobial activity against Pseudomonas aeruginosa (85% when extracted with phosphate buffer (PB) and 100% when extracted with phosphate buffer saline (PBS)), Streptococcus agalactiae (100% for both extracts), Staphylococcus aureus (67% when extracted with PBS and 100% when extracted with PB), Escherichia coli (72% when extracted with PB and 89% when extracted with PBS), Streptococcus pyogenes (about 85% for both extracts) and Candida albicans (around 70% for both extracts), comparable with that obtained for the PAB. However, at lower concentrations the PAB exhibited in general higher antimicrobial activities. Biosurfactants produced by both microorganisms also showed significant anti-adhesive properties against all the microorganisms under study, except for E. coli and C. albicans (less than 30%). Overall, these cell-bound biosurfactants could be used as potential antimicrobial and anti-adhesive agents in cosmetic and pharmaceutical formulations.

Novel cosmetic formulations containing a biosurfactant from Lactobacillus paracasei

Cosmetic and personal care products including toothpaste, shampoo, creams, makeup, among others, are usually formulated with petroleum-based surfactants, although in the last years the consume trend for "green" products is inducing the replacement of surface-active agents in these formulations by natural surfactants, so-called biosurfactants. In addition to their surfactant capacity, many biosurfactants can act as good emulsifiers, which is an extra advantage in the preparation of green cosmetic products. In this work, a biosurfactant obtained from Lactobacillus paracasei was used as a stabilizing agent in oil-in-water emulsions containing essential oils and natural antioxidant extract. In the presence of biosurfactant, maximum percentages of emulsion volumes (EV=100%) were observed, with droplets sizes about 199nm. These results were comparable with the ones obtained using sodium dodecyl sulfate (SDS), a synthetic well known surfactant with high emulsify capacity. Moreover, the biosurfactant and emulsions cytotoxicity was evaluated using a mouse fibroblast cell line. Solutions containing 5g/L of biosurfactant presented cell proliferation values of 97%, whereas 0.5g/L of SDS showed a strong inhibitory effect. Overall, the results herein gathered are very promising towards the development of new green cosmetic formulations.

Biosurfactants in cosmetic formulations: trends and challenges

Cosmetic products play an essential role in everyone's life. People everyday use a large variety of cosmetic products such as soap, shampoo, toothpaste, deodorant, skin care, perfume, make-up, among others. The cosmetic industry encompasses several environmental, social and economic impacts that are being addressed through the search for more efficient manufacturing techniques, the reduction of waste and emissions and the promotion of personal hygiene, contributing to an improvement of public health and at the same time providing employment opportunities. The current trend among consumers is the pursuit for natural ingredients in cosmetic products, as many of these products exhibit equal, better or additional benefits in comparison with the chemical-based products. In this sense, biosurfactants are natural compounds with great potential in the formulation of cosmetic products given by their biodegradability and impact in health. Indeed, many of these biosurfactants could exhibit a "prebiotic" character. This review covers the current state-of-the-art of biosurfactant research for cosmetic purposes and further discusses the future challenges for cosmetic applications.

Influence of micelle formation on the adsorption capacity of a biosurfactant extracted from corn on dyed hair

Biosurfactants obtained from corn steep liquor were applied to dyed hair and showed good adsorption while maintaining the dyed hair structure in a good state.

A multifunctional extract from corn steep liquor: antioxidant and surfactant activities

In the last few years the awareness of consumers and institutions about the impact that our industrial processes has on health and the environment has increased, demanding more natural products. In this work, a multifunctional bioactive extract with surfactant and antioxidant properties, composed mainly of C16 and C18 fatty acids, and phenolic compounds (vanillic acid, p-coumaric acid, ferulic acid, sinapic acid and quercetin) was obtained from corn steep liquor (CSL). Different liquid-liquid extraction protocols were evaluated obtaining a natural extract, which was able to reduce the surface tension of water by more than 30 units, showing antioxidant activity with an EC50 of 8.51 mg mL(-1) and a yield of 6.85 g of extract per kg of CSL. Additionally, it was observed that after liquid-liquid extraction with chloroform, the aqueous phase can be subjected to a hydrothermal treatment, followed by extraction with ethyl acetate, in order to obtain another extract (24.7 g of extract per kg of CSL) with a higher antioxidant capacity (EC50 of 4.02 mg mL(-1)). In this case the antioxidant extract is composed of protocatechuic acid, vanillic acid, caffeic acid, epicatechin, p-coumaric acid, ferulic acid, sinapic acid and quercetin.

Adsorption of natural surface active compounds obtained from corn on human hair

In this work, an aqueous solution containing surface-active compounds, extracted from corn steep liquor (CSL), was added to human hair and its adsorption was studied by applying an incomplete factorial design.

Formulation of an alginate-vineyard pruning waste composite as a new eco-friendly adsorbent to remove micronutrients from agroindustrial effluents

The cellulosic fraction of vineyard pruning waste (free of hemicellulosic sugars) was entrapped in calcium alginate beads and evaluated as an eco-friendly adsorbent for the removal of different nutrients and micronutrients (Mg, P, Zn, K, N-NH4, SO4, TN, TC and PO4) from an agroindustrial effluent (winery wastewater). Batch adsorption studies were performed by varying the amounts of cellulosic adsorbent (0.5-2%), sodium alginate (1-5%) and calcium chloride (0.05-0.9M) included in the biocomposite. The optimal formulation of the adsorbent composite varied depending on the target contaminant. Thus, for the adsorption of cationic contaminants (Mg, Zn, K, N-NH4 and TN), the best mixture comprised 5% sodium alginate, 0.05M calcium chloride and 0.5% cellulosic vineyard pruning waste, whereas for removal of anionic compounds (P, SO4 and PO4), the optimal mixture comprised 1% sodium alginate, 0.9M calcium chloride and 0.5% cellulosic vineyard pruning waste. To remove TC from the winery wastewater, the optimal mixture comprised 3% of sodium alginate, 0.475M calcium chloride and 0.5% cellulosic vineyard pruning waste.

Study of the surfactant properties of aqueous stream from the corn milling industry

Corn steep liquor (CSL) is a liquid byproduct generated by the corn wet-milling industry. This agroindustrial residue is obtained when corn is digested with warm water and SO2 in the presence of different spontaneously growing microorganisms. The microbial population of CSL includes lactic acid bacteria, which are widely known to produce biosurfactants. However, there is no information available about the possible existence of surface-active compounds in CSL. In this work the surface tension activity of CSL was evaluated and the biosurfactant contained in this residue was extracted with different organic solvents and characterized. The biosurfactant obtained from CSL was analyzed by Fourier transform infrared spectroscopy, and the composition in fatty acid was analyzed by gas chromatography-mass spectrometry. The hydrophobic chain of the biosurfactant contained in CSL comprised 50-55.2% linolelaidic acid, 15.7-22.2% oleic and/or elaidic acid, 5.9-14.6% stearic acid, and 14.9-19.6% palmitic acid.

Evaluation of biosurfactant obtained from Lactobacillus pentosus as foaming agent in froth flotation

This study analyzes the kinetics of sediment sorption on two chemical surfactants (Tween 20 and SDS) and a biotechnologically produced surfactant (obtained from Lactobacillus pentosus). Biosurfactants were produced by fermentation of hemicellulosic sugars from vineyard pruning waste supplied as a substrate to L. pentosus. Results obtained showed that almost no SDS was adsorbed onto the sediments, whereas Tween 20 and biosurfactants from L. pentosus were absorbed after a few minutes. Kinetic models revealed that adsorption of surfactant onto riverbed sediments is governed not only by an intra-particle diffusion model (evaluated by the Weber and Morris model), but also by surface reaction models (evaluated by first, second, third order equations and Elovich equation), showing the best fit when employing the Elovich model. The adsorption properties showed by biosurfactant from L. pentosus onto sediments present it as a potential foaming agent in froth flotation.

Removal of pigments from aqueous solution by a calcium alginate-grape marc biopolymer: a kinetic study

In this work, the potential use of a biopolymer based on grape marc entrapped in calcium alginate beads for the removal of pigments from an agro industrial effluent was evaluated. The parameters that affect the pigment adsorption such as pH (3.5-7.0), temperature (10-40°C) and initial pigment concentration (6.9-55.1mg/L) were studied by applying an incomplete factorial design. The dependent variables evaluated consisted of color effluent parameters from CIELAB and Tristimulus system, as well as the concentration of pigments in the wastewater after the adsorption treatment. The most significant independent variables tested were the pigments concentration followed by pH, whereas temperature had a negligible effect on the adsorption process. Moreover, at the optimal operational conditions (pH 3.5 and room temperature) kinetic studies were carried out by applying pseudo-first order, pseudo-second order, Chien-Clayton and intraparticle diffusion models, observing a good agreement between theoretical and experimental results.

Valorization of winery waste vs. the costs of not recycling

Wine production generates huge amounts of waste. Before the 1990s, the most economical option for waste removal was the payment of a disposal fee usually being of around 3000 Euros. However, in recent years the disposal fee and fines for unauthorized discharges have increased considerably, often reaching 30,000-40,000 Euros, and a prison sentence is sometimes also imposed. Some environmental friendly technologies have been proposed for the valorization of winery waste products. Fermentation of grape marc, trimming vine shoot or vinification lees has been reported to produce lactic acid, biosurfactants, xylitol, ethanol and other compounds. Furthermore, grape marc and seeds are rich in phenolic compounds, which have antioxidants properties, and vinasse contains tartaric acid that can be extracted and commercialized. Companies must therefore invest in new technologies to decrease the impact of agro-industrial residues on the environment and to establish new processes that will provide additional sources of income.

Optimisation of entrapped activated carbon conditions to remove coloured compounds from winery wastewaters

The objective of this work was to study the entrapped conditions of activated carbon in calcium-alginate beads for the clarification of winery wastewaters. An incomplete 3(3) factorial design was carried out to study the efficiency of activated carbon (0.5-2%); sodium alginate (1-5%); and calcium chloride (0.050-0.900 M), on the following dependent variables: colour reduction at 280, 465, 530 and 665 nm. The activated carbon and calcium chloride were the most influential variables in the colour reduction. Nearly 100% colour reductions were found for the wavelengths assayed when employing 2% of activated carbon, 5% of sodium alginate and intermediate concentrations of calcium chloride (0.475 M). Instead, other conditions like, 2% of activated carbon, 4% of sodium alginate and 0.580 M of calcium chloride can also give absorbance reductions close to 100%.

Phase-flip transition in coupled electrochemical cells

Time delay is introduced in the coupling between a pair of electrochemical cells. As coupling parameters are varied, the anodic current in the two cells oscillate in synchrony in regimes of periodic as well as chaotic dynamics. When the time delay is varied a phase-flip transition is observed: the relative phase between the synchronized oscillations changes abruptly by pi . This is accompanied by an experimentally measurable discontinuous change in the frequency of the synchronized oscillators.

Mitral valve replacement in sickle cell disease

Cardiac dysfunction, including mitral valve regurgitation and congestive heart failure, can occur in patients with sickle cell disease. However, major surgery poses a greater risk in this population. This paper reports on the management of a patient with sickle cell disease who underwent successful replacement of the mitral valve.

[Tunneled catheters. Complications during insertion]

INTRODUCTION

The creation of vascular accesses for hemodialysis in patients affected with terminal kidney failure affections, is presented periodically as a problem. Because of it, the availability of alternatives to the arteriovein fistula is something necessary; different types of tunnelled dialysis catheters are being developed, among which the Tesio catheter is the most well known and most widely utilized. Often it is implanted by vascular surgeons or radiologists; this creates dependence for the nephrology services that can delay obtaining the new vascular access and initiating or reinitiating the treatment.

MATERIAL AND METHODS

A descriptive study with the objective of analyzing the immediate complications during the insertion of tunnelled central catheters for hemodialysis and to evaluate the possibility of its attainment was carried out by nephrologists and personnel specialized in dialysis. Between January of 2003 and December of 2005, 175 Tesio tunnelled central catheters were implanted in our hemodialysis unit. Age and sex of the patient was registered, time in dialysis, diagnosis of hypertension, diabetes mellitus or prior heart disease, previous anticoagulant or platelet antiaggregate treatment, difficulty perceived by the nephrologist for the development of the technique, bleeding, systolic and diastolic arterial pressure, cardiac frequency, oxygen saturation and changes in the monitoring of electrocardiogram, at the beginning of the intervention, during the channelling of the vein, insertion of the dilatators and catheter, and at the end of it.

RESULTS

The patients were 88 men and 82 women, with an average of age of 64. 21% of the patients habitually followed a treatment with platelet antiaggregate or anticoagulant, which had been withdrawn in the prior days. The ultrasound size of the vein was greater than one cm in 79% of the cases. Of 175 insertions only three patients (2%) presented signs of hemodynamic instability, two of them due to a descent of arterial tension and one by oxygen saturation descent; none of them required assisted backup, neither hemorrhage nor other complications appeared.

CONCLUSIONS

The implant of tunnelled catheters, under local anesthesia, presents minimal complications and incidents during its insertion. It can be carried out by a nephrologist and specialized personnel, in hospitals with backup units that can undertake any possible complications.

Control, synchronization, and replicability of aperiodic spike trains

Aperiodic spike sequences, characterized by an almost constant spike amplitude and randomly distributed interspike intervals, are studied experimentally in an electrochemical cell. In the first set of experiments, these aperiodic spike trains are converted to regular spike sequences using periodic forcing. Subsequently, synchronization of two such irregular spike time series is achieved for an appropriate bidirectional coupling. Finally, reproducibility of these irregular spike profiles is evoked by virtue of an externally superimposed stochastic stimulus.

Variations in liver and blood copper concentrations in young beef cattle raised in north-west Spain: associations with breed, sex, age and season

The aim of the present study was to evaluate the influence of breed and other factors (age, sex and season) on copper (Cu) accumulation by calves reared in a region in north-west Spain where pig slurry is widely used for slurry fertilization, and where cattle typically have hepatic Cu concentrations above the generally accepted safe-adequate levels. In December 2000 and August 2001, paired liver and blood samples were obtained at slaughter from 532 male and female Galician Blond, Holstein-Friesian and Galician Blond×Holstein-Friesian calves, aged between 6 and 10 months, from 434 different farms. Samples were acid-digested and Cu concentrations determined by ICP-OES. Holstein-Friesian calves showed significantly higher mean Cu concentrations both in the liver (80·6 mg/kg fresh weight) and blood (0·891 mg/l) than Galician Blond calves (50·4 mg/kg and 0·748 mg/l respectively) and crosses between the two breeds (61·3 mg/kg and 0·829 mg/l respectively). Holstein-Friesian was the breed with the highest percentage (42%) of calves with hepatic Cu concentrations above safe-adequate levels (25 to 100 mg/kg fresh weight) and Galician Blond the breed with the highest proportion (29%) of hypocupraemia during the winter sampling. Considering all breeds, hepatic Cu levels were higher in males (63·8 mg/kg) than in females (53·5 mg/kg) and significantly increased with age in summer. A significant three-way breed×sex×age interaction was observed for liver Cu but this may be attributable to the small number of animals in some groups, having a confounding effect on the analysis. A significant sex×age×season interaction was also observed which could indicate greater male dominance in summer, so that they consume more forage (and thus more Cu) than females. Calves slaughtered in winter showed significantly lower mean blood Cu concentration (0·703 mg/l) than calves slaughtered in summer (0·940 mg/l).

Experimental observation of different types of chaotic synchronization in an electrochemical cell

Chaotic synchronization for a pair of electrochemical oscillators is studied experimentally. The underlying bidirectional coupling between the two oscillators is achieved by immersing the two anodes in a common electrolytic solution. The horizontal distance between these two electrodes determines the strength of the coupling constant. On monotonically decreasing the distance between the two anodes, different domains of chaotic synchronization, namely, no, phase, lag, and complete synchronization, are identified. Furthermore, dynamics from the different transition intervals are also characterized.

[DOPPS estimate of patient life years attributable to modifiable hemodialysis practices in Spain]

The increased mortality risk in hemodialysis (HD) patients unable to meet six targets in different areas of HD practice has been reported previously. Using a prevalent cross-sectional sample of Spanish HD patients (n = 613) from the second stage of the Dialysis Outcomes and Practice Patterns Study to determine the percentage with low dialysis dose, hyperphosphatemia, hypercalcemia, hypoalbuminemia, anemia, and catheter use and based on the mortality hazard ratios and the total HD population in Spain, according to the Spanish Society of Nephrology Report, we estimated the number of patient life years that could potentially be gained in our country. These characteristics of HD practice were selected because each is modifiable through changes in practice, each is associated with mortality, and each has a large number of patients outside the target guidelines. The targets that define "within guidelines" are as follows: dialysis dose (single pool Kt/V >1.2), anemia (hemoglobin >110 g/L), albumin after standardization (>40 g/L), serum phosphorus (1.1-1.5 mmol/L), serum calcium (2.1-2.4 mmol/L), and facility catheter use (<10%). Cox proportional hazards regression models were used to calculate the relative risk of mortality for all patients outside each guideline. In all models, calcium values were adjusted for low serum albumin. A separate Cox survival model adjusted for all six HD practices simultaneously to account for correlation that may exist between some facility practices. All models were adjusted for age, sex, race, time on ESRD, and 14 summary comorbid conditions. Patient years attributable to each of the six practice patterns were estimated and are reported here as the potential patient years gained. Comparison of the estimates by individual guideline shows that, in Spain, increasing patient albumin above 40 g/L in all patients would lead to an estimated gain of 9,269 patient years (a 7.9% increase). Additionally, if all facilities could decrease catheter use to less than 10%, 2,842 patient years could be gained (a 2.4% increase). Though it may be an unrealistic goal, if all Spanish patients currently outside the guidelines achieved all six target levels, an estimated 17,300 life years could be gained over the next five years (a 15% increase). A more achievable goal of bringing 50% of patients who are currently outside targets within targets would result in 9,266 life years gained. In conclusion, this analysis suggests large opportunities to improve HD patient care in Spain.

Influence of copper status on the accumulation of toxic and essential metals in cattle

The aim of the present study was to assess whether the use of pig slurry and associated copper accumulation in calves grazing pastures fertilized with pig slurry from the Deza region in NW Spain has a significant influence on toxic metal and essential metal levels, and to investigate whether copper accumulation is correlated with the levels of these other metals. Correlations between copper, toxic metals (cadmium, lead) and essential metals (molybdenum, iron, zinc, selenium, manganese and cobalt) concentrations were evaluated in liver and kidney of 195 calves from the region of Deza. Metal concentrations were determined by ICP-OES and correlations between pairs of elements by Pearson correlation analysis. There was a strongly significant positive association between copper and lead in the liver. Considering the trace metals, copper in the liver showed significant positive correlations with cobalt in both liver and kidney, and with molybdenum in the liver. In addition, significant correlations were observed between copper and most essential metals in kidney. These associations are similar to those found in different animal species experimentally dosed with copper and other metals, as well as in cattle exposed to normal copper concentrations.

[Infective endocarditis in the elderly]

BACKGROUND

The influence of age on the clinical presentation and on the prognosis of infective endocarditis (IE) is unclear. Our aim was to analyse the epidemiologic, clinical and bacteriological characteristics of IE in the elderly compared with younger adult patients. PATIENTS AND METHODS A retrospective study of all patients with IE non intravenous drug users diagnosed in our hospital during the period from 1990 to 2000. We used the Duke criteria to compare the characteristics of 46 episodes of definitive IE in elderly patients (>65 years old ) and of 46 episodes in younger adult patients (20-64 years of age ).

RESULTS

No significant differences were observed among the two groups with respect to the delay in diagnosed, possible source of infection, the frequency of positive blood cultures and the type of infective organism, clinical presentation and evolution of the IE. Elderly patients more often had risk factors predisposing (degenerative valvular disease, prosthetic valve and pacemaker ), which decreased the sensitivity of transthoracic echocardiography to 46.5% compared with 64.4% in the younger patients. Transesophageal echocardiography improved the diagnostic of IE in the 37.2% in elderly patients. The patients in the both groups underwent surgical therapy with similar frequency (36.9% in the elderly and the 39.1% in the younger adult patient ) and the mortality rate not was significantly higher in the elderly (19.5%) than in the younger adult patients (10.8%).

CONCLUSIONS

The age itself is not a poor prognostic, and should not be used prejudicially in denying a early and aggressive treatment of the patients with IE.

[Results of the international hemodialysis study DOPPS in Spain and Europe]

The Dialysis Outcomes and Practice Pattern Study (DOPPS) is an international observational study of treatment conditions and medical outcomes in hemodialysis patients. Prospective sampling has yielded long-term observational data from randomly selected groups of patients receiving treatment at representative, randomly selected hemodialysis units in each country. The data shown were collected at 20 hemodialysis units/centers in Spain. The data pertaining to Spain--Sp--refers to 575 patients and their comparison with those of the Euro-DOPPS countries--Eu--(Germany, France, United Kingdom, Italy and Spain), which encompass 3,038 patients, represent the formal goal of this paper. Diabetes mellitus, at 21.5% in Eu and 21.7% in Sp, was the most common cause of renal insufficiency in dialysis and coronariopathy, as a concomitant disease, was present in 67.8% in Eu as opposed to 75.8% in Sp. Differences were observed in the incident of hypertension (73.4% in Eu vs 77.4% in Sp), hepatitis C (11.6% vs 19.5%), depression (12.7 vs 16.2%) and left ventricular hypertrophy (54.9% vs 62.3%). The patterns of vascular access were similar (79% vs 81% AV fistulas in Eu and Sp, and 10% synthetic grafts for both) and the mean applied dose of dialysis--Kt/V--smaller (1.19) in Sp than in Eu (1.24); likewise the duration of the dialysis (in minutes) was shorter (234 in Eu vs 217 in Sp) and the % of synthetic membranes used was smaller (60% in Eu vs 52% in Sp). There were no differences between the groups in the figures for urea, creatinine, albumin, nPCR, calcium, phosphate or PTH. There were also no differences in the mean values of Hb (10.7 for Eu vs 10.8 for Sp), given that the values of ferritin were noticeably lower in Sp (288 vs 355) and the dose of EPO/kg/week was higher to in Sp (115 vs 102); s.c. route was used in similar proportions (69% in Eu vs 67% in Sp). The level of medical care, understood as contact with the physician at all or almost all treatments, was noticeably better in Sp (90%) that in Eu (66%), whereas the number of patients per hour of specialized personnel and % of specialized staff, were smaller. Mortality (death/100 patients-years) was one point lower in Sp than in Eu (15.4 vs 16.3). These data suggest that an increment in dialysis time and in the percentage of synthetic membranes used, as well as in the supply of intravenous iron, would be justified.

An outbreak of legionnaires' disease in a municipality in northern Portugal

Eleven cases of legionnaires' disease, all patients living in the same municipality, were admitted to a district hospital in northern Portugal. Preliminary investigations suggested an association with the events of the annual festivities in that municipality. Legionella pneumophila was not isolated from any of the suspected sources, but evidence from a case control study suggested that an aerosol produced by a decorative fountain in the main square during the night of a rock concert was the likely vehicle of infection. The prevalence of smoking was higher among cases than controls.

An outbreak of legionnaires’ disease in a municipality in northern Portugal

Eleven cases of legionnaires´ disease, all patients living in the same municipality, were admitted to a district hospital in northern Portugal. Preliminary investigations suggested an association with the events of the annual festivities in that municipality. Legionella pneumophila was not isolated from any of the suspected sources, but evidence from a case control study suggested that an aerosol produced by a decorative fountain in the main square during the night of a rock concert was the likely vehicle of infection. The prevalence of smoking was higher among cases than controls.

An outbreak of legionnaires disease in a municipality in northern Portugal

Eleven cases of legionnaires disease, all patients living in the same municipality, were admitted to a district hospital in northern Portugal. Preliminary investigations suggested an association with the events of the annual festivities in that municipality. Legionella pneumophila was not isolated from any of the suspected sources, but evidence from a case control study suggested that an aerosol produced by a decorative fountain in the main square during the night of a rock concert was the likely vehicle of infection. The prevalence of smoking was higher among cases than controls.

Information needs and information-seeking behaviors of HIV positive men and women

Although a portion of the HIV/AIDS population has long been active in seeking out information in support of self-care, little work has been done to examine closely the information needs and information-seeking behaviors of this community relative to the provision of medical reference. This exploratory study provides insight into the types of information HIV positive individuals seek and the resources they consult in gathering information to bolster health and well-being. Having a better understanding of the information needs and information-seeking behaviors of individuals with HIV/AIDS will facilitate information intervention for this community.

Antioxidant and antimicrobial effects of extracts from hydrolysates of lignocellulosic materials

The antioxidant and antimicrobial activities of ethyl acetate extracts obtained from acid hydrolysates of several lignocellulosic materials (Eucalyptus globulus wood, barley bran, corn cobs, and corn leaves) were evaluated. The minimum inhibitory and bactericide concentrations (MIC and MBC, respectively) were determined against a selection of bacteria and yeasts. Extracts from Eucalyptus wood hydrolysates were the most active for inhibiting bacteria and yeast growth, with MIC in the range of 10(2)--5 x 10(3) microg/mL and MBC in the range of 10(3)--0(5) microg/mL. Bacteriogenic and bacteriostatic activities of extracts from Eucalyptus wood and barley bran acid hydrolysates were slightly higher than those of corn cobs and leaves. Both the radical scavenging capacity and the inhibition of the beta-carotene bleaching caused by extracts were determined and compared with those of synthetic antioxidants. The antioxidant activity of extracts increased with their concentrations in the media, the stronger properties corresponding to those obtained from Eucalyptus wood hydrolysates.

Family violence and substance use: the perceived effects of substance use within gay male relationships

The purpose of this research endeavor is to examine the life situations of gay men where domestic violence was present. The current article expands on previously published works by examining respondents' perceptions of what role alcohol and other drug use plays in causing substance use-related domestic violence. Three different perceptions emerged from the data and are presented here. First, drugs and alcohol use was perceived to be causally related to the domestic violence our respondents endured. Second, our respondents believed substance abuse resulted from the violence--it was used as a coping mechanism. Finally, many respondents did not believe there was any association between substance abuse and violence. The need for further in-depth data related to the relationship between drugs, alcohol, and domestic violence is noted.

Bone marrow cytogenetic abnormalities of aplastic anemia

Cytogenetic abnormalities in association with aplastic anemia have been reported fairly infrequently. Clonal cytogenetic abnormalities at initial diagnosis are uncommon. A retrospective study was performed of the cytogenetic findings in patients with typical morphological and clinical features of severe aplastic anemia from a single institution for the years 1988 through 1998. A total of 30 cases of aplastic anemia, 16 men and 14 women, were identified. The median age was 60 with females being significantly older (67.5 years) in comparison to males (44 years). Bone marrow specimens failed to yield metaphases in 16 cases and normal karyotypes were detected in 11 cases. Cytogenetic abnormalities were detected in 3 cases. Clonal abnormalities, as defined, occurred in only 2 cases (6.7%). A review of the literature identified a total of 24 cases of aplastic anemia with abnormal cytogenetic findings. Overall, the most common chromosome abnormalities are trisomies of 6 and 8 and loss of chromosome 7. Trisomy 6 is more common at diagnosis while loss of chromosome 7 is more common after therapy.

Detection of abnormal pretransplant clones in progenitor cells of patients who developed myelodysplasia after autologous transplantation

Secondary myelodysplastic syndromes (MDS) have been reported after autologous transplantation. It is not known whether the MDS results from the pretransplant conventional-dose chemotherapy or from the high-dose chemotherapy (HDC) used for the transplant procedure. We performed a multicenter, retrospective analysis of morphologically normal pretransplant marrow or stem cell specimens from 12 patients who subsequently developed myelodysplasia after HDC. To determine if the abnormal clone was present before HDC, we used fluorescence in situ hybridization (FISH) to detect the cytogenetic markers observed at the onset of posttransplant MDS. Cryopreserved, pretransplant bone marrow, peripheral blood stem cell specimens, obtained at the time of harvest, or archival smears were used. Standard cytogenetic analysis had been performed pretransplant in four patients, showing a normal karyotype. In 9 of 12 cases, the same cytogenetic abnormality observed at the time of MDS diagnosis was detected by FISH in the pre-HDC specimens. Our findings support the hypothesis that, in many cases of posttransplant MDS, the stem cell damage results from prior conventional-dose chemotherapy and may be unrelated to HDC or the transplantation process itself.

[Victimization by urban violence: incidence and associated factors in cities in Latin America and Spain]

This article looks at eight cities in Latin America and Spain and compares the chances of and variables associated with being a victim of various kinds of urban violence. The analysis was done using data from the ACTIVA Multicenter Study, which was coordinated by the Pan American Health Organization in 1996. The study sample consisted of 10,821 persons who were representative of residents between the ages of 18 and 70 in eight metropolitan areas of Latin America and Spain: Rio de Janeiro, Brazil; Salvador, Brazil; Santiago, Chile; Cali, Colombia; San José, Costa Rica; San Salvador, El Salvador; Caracas, Venezuela; and Madrid, Spain. The results show that the likelihood of being a victim of different types of violence varies from city to city. The variables associated with a greater likelihood of being a victim in most--though not all--of the cities are sex, age, and consumption of alcohol.

[Psychosocial impact of violence in San Salvador]

This study had two objectives: (1) to describe the levels of victimization of Salvadorians due to criminal violence, and the population groups most affected by it; (2) to learn if these levels of victimization are related to the presence of norms, attitudes, and behaviors that encourage the occurrence of violence. For this purpose data from the ACTIVA project of El Salvador were used. The project was carried out by the University Institute of Public Opinion during October and November 1996, with a sample of 1,290 personal interviews that were presumed to be representative of people between 18 and 70 years of age living in the Metropolitan Area of San Salvador. The sample was obtained through multistage probability sampling. The results show that the level of victimization from violence is quite high in San Salvador and that it especially affects adult and young men. The results also indicate that persons who have been victims of serious aggression tend to show, more frequently than average, norms justifying and approving the use of violence, a tendency to use weapons, and aggressive behaviors toward other people.

Xylitol Production from Wood Hydrolyzates by Entrapped Debaryomyces hansenii and Candida guilliermondii Cells

Debaryomyces hansenii cells were entrapped in Ca-alginate beads and used for producing xylitol from wood hydrolyzates. Batch experiments showed that bioconversion was severely hindered when Ca-alginate beads were hardened with Al3+ solutions. As an alternative to Al3+ hardening, the improvements in both mechanical stability of bioparticles and fermenting ability of the immobilized system derived from using increased concentrations of sodium alginate were assessed. The best results were obtained using a 4% (w/v) Na-alginate solution in the gelification step. This concentration was selected to perform continuous fermentations in a packed-bed reactor using raw or charcoal-treated hydrolyzates (15.5 g of xylose/L) with two different yeasts: Candida guilliermondii and Debaryomyces hansenii. With a final cell concentration of about 50 g of cells/L (0.075 g of cells/g of beads), the volumetric productivities reached with these yeasts in media made from charcoal-treated hydrolyzates were 0.58 and 0.91 g/L.h, respectively.