Extraction of Ascorbate Oxidase from Cucurbita maxima by Continuous Process in Perforated Rotating Disc Contactor Using Aqueous Two-Phase Systems

The ascorbate oxidase is the enzyme used to determine the content of ascorbic acid in the pharmaceutical and food industries and clinics analyses. The techniques currently used for the purification of this enzyme raise its production cost. Thus, the development of alternative processes and with the potential to reduce costs is interesting. The application of aqueous two-phase system is proposed as an alternative to purification because it enables good separation of biomolecules. The objective of this study was to determine the conditions to continuously pre-purify the enzyme ascorbate oxidase by an aqueous two-phase system (PEG/citrate) using rotating column provided with perforated discs. Under the best conditions (20,000 g/mol PEG molar mass, 10% PEG concentration, and 25% citrate concentration), the system showed satisfactory results (partition coefficient, 3.35; separation efficiency, 54.98%; and purification factor, 1.46) and proved suitable for the pre-purification of ascorbate oxidase in continuous process.

Sterilization of Medical Devices by Ethylene Oxide, Determination of the Dissipation of Residues, and Use of Green Fluorescent Protein as an Indicator of Process Control

Ethylene oxide (EO) is used to sterilize Oxygenator and Tubing applied to heart surgery. Residual levels of EO and its derivatives, ethylene chlorohydrin (ECH) and ethylene glycol (EG), may be hazardous to the patients. Therefore, it must be removed by the aeration process. This study aimed to estimate the minimum aeration time for these devices to attain safe limits for use (avoiding excessive aeration time) and to evaluate the Green Fluorescent Protein (GFP) as a biosensor capable of best indicating the distribution and penetration of EO gas throughout the sterilization chamber. Sterilization cycles of 2, 4, and 8 h were monitored by Bacillus atrophaeus ATCC 9372 as a biological indicator (131) and by the GFP. Residual levels of EO, ECH, and EG were determined by gas chromatography (GC), and the residual dissipation was studied. Safe limits were reached right after the sterilization process for Oxygenator and after 204 h of aeration for Tubing. In the 2 h cycle, the GFP concentration decreased from 4.8 (+/- 3.2)% to 7.5 (+/- 2.5)%. For the 4 h cycle, the GFP concentration decreased from 17.4 (+/- 3.0)% to 21.5 (+/- 6.8)%, and in the 8 h cycle, it decreased from 22.5 (+/- 3.2)% to 23.9 (+/- 3.9)%. This finding showed the potentiality for GFP applications as an EO biosensor. (C) 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 9113: 626-630, 2009

Aqueous two-phasemicellar systems in an oscillatory flowmicro-reactor: study of perspectives and experimental performance

BACKGROUND: Aqueous two-phase micellar systems (ATPMS) are micellar surfactant solutions with physical properties that make them very efficient for the extraction/concentration of biological products. In this work the main proposal that has been discussed is the possible applicability and importance of a novel oscillatory flow micro-reactor (micro-OFR) envisaged for parallel screening and/or development of industrial bioprocesses in ATPMS. Based on the technology of oscillatory flow mixing (OFM), this batch or continuous micro-reactor has been presented as a new small-scale alternative for biological or physical-chemical applications. RESULTS: ATPMS experiments were carried out in different OFM conditions (times, temperatures, oscillation frequencies and amplitudes) for the extraction of glucose-6-phosphate dehydrogenase (G6PD) in Triton X-114/buffer with Cibacron Blue as affinity ligand. CONCLUSION: The results suggest the potential use of OFR, considering this process a promising and new alternative for the purification or pre-concentration of bioproducts. Despite the applied homogenization and extraction conditions have presented no improvements in the partitioning selectivity of the target enzyme, when at rest temperature they have influenced the partitioning behavior in Triton X-114 ATPMS. (C) 2011 Society of Chemical Industry

Continuous extraction of alpha-toxin from a fermented broth of Clostridium perfringens Type A in perforated rotating disc contactor using aqueous two-phase PEG-phosphate system

A 2(3-1) factorial experimental design was used to evaluate the performance of a perforated rotating disc contactor to extract alpha-toxin from the fermented broth of Clostridium perfringens Type A by aqueous two-phase system of polyethylene glycol-phosphate salts. The influence of three independent variables, specifically the dispersed phase flowrate, the continuous phase flowrate and the disc rotational speed, was investigated on the hold up, the mass transfer coefficient, the separation efficiency and the purification factor, taken as the response variables. The optimum dispersed phase flowrate was 3.0 mL/min for all these responses. Besides, maximum values of hold up (0.80), separation efficiency (0. 10) and purification factor (2.4) were obtained at this flowrate using the lowest disc rotational speed (35 rpm), while the optimum mass transfer coefficient (0. 165 h(-1)) was achieved at the highest agitation level (140 rpm). The results of this study demonstrated that the dispersed phase flowrate strongly influenced the performance of PRDC, in that both the mass transfer coefficient and hold up increased with this parameter. (c) 2007 Elsevier B. V. All rights reserved.

Use of diamond-like carbon with tungsten (W-DLC) films as biocompatible material

Diamond-like carbon (DLC), also known as amorphous hydrogenated carbon (a-C:H), are a class of materials with excellent mechanical, tribological and biological properties. When the DLC films are enhanced with other elements, all of these properties can be changed within a certain range. In this work, reactive magnetron sputtering was used to deposit W-DLC (hydrogenated tungsten carbide) films on Ti6A14V (implant material). Many films were made using pure tungsten (99.99%) target and different plasmas processes, with different ratio among argon and methane. It was possible to change the films composition (from pure amorphous carbon to carbon enhanced with tungsten) according to ratio of argon and methane plasma. Between all films processed, the carbon films enhanced with tungsten showed good results in the ""in vitro"" cytotoxicity testing. Raman spectroscopy was used to analyze the chemical bonds kinds and the chemical bonds quantities. The Rutherford Back Scattering (RBS) was used to analyze the films compositions. The chemical inertness was analyzed by scanning voltametry. W-DLC thin films obtained in these processes have low roughness, high chemical resistance, good adhesion and show a high biocompatibility, when compared with common DLC thin films. Hence we have concluded that the tungsten concentrations in the DLC films make an important role to improve the properties of the DLC layers. (C) 2007 Elsevier B.V. All rights reserved.

In vitro studies of cutaneous retention of magnetic nanoemulsion loaded with zinc phthalocyanine for synergic use in skin cancer treatment

In this study was developed a new nano drug delivery system (NDDS) based on association of biodegradable surfactants with biocompatible magnetic fluid of maguemita citrate derivative. This formulation consists in a magnetic emulsion with nanostructured colloidal particles. Preliminary in vitro experiments showed that the formulation presents a great potential for synergic application in the topical release of photosensitizer drug (PS) and excellent target tissue properties in the photodynamic therapy (PDT) combined with hyperthermia (HPT) protocols. The physical chemistry characterization and in vitro assays were carried out by Zn(II) Phtalocyanine (ZnPc) photosensitizer incorporated into NDDS in the absence and the presence of magnetic fluid, showed good results and high biocompatibility. In vitro experiments were accomplished by tape-stripping protocols for quanti. cation of drug association with different skin tissue layers. This technique is a classical method for analyses of drug release in stratum corneum and epidermis+ dermis skin layers. The NDDS formulations were applied directly in pig skin (tissue model) fixed in the cell`s Franz device with receptor medium container with a PBS/EtOH 20% solution (10mM, pH 7.4) at 37 degrees C. After 12 h of topical administration stratum corneum was removed from fifty tapes and the ZnPc retained was evaluated by solvent extraction in dimetil-sulphoxide under ultrasonic bath. These results indicated that magnetic nanoemulsion (MNE) increase the drug release on the deeper skin layers when compared with classical formulation in the absence of magnetic particles. This could be related with the increase of biocompatibility of NDDS due to the great affinity for the polar extracelullar matrix in the skin and also for the increase in the drug partition inside of corneocites wall. (C) 2008 Elsevier B.V. All rights reserved.

Use of virtual screening, flexible docking, and molecular interaction fields to design novel HMG-CoA reductase inhibitors for the treatment of hypercholesterolemia

Dietary changes associated with drug therapy can reduce high serum cholesterol levels and dramatically decrease the risk of coronary artery disease, stroke, and overall mortality. Statins are hypolipemic drugs that are effective in the reduction of cholesterol serum levels, attenuating cholesterol synthesis in liver by competitive inhibition regarding the substrate or molecular target HMG-CoA reductase. We have herewith used computer-aided molecular design tools, i.e., flexible docking, virtual screening in large data bases, molecular interaction fields to propose novel potential HMG-CoA reductase inhibitors that are promising for the treatment of hypercholesterolemia.

Processing of Rosmarinus officinalis Linne extract on spray and spouted bed dryers

This article presents an investigation of the potential of spray and spouted bed technology for the production of dried extracts of Rosmarinus officinalis Linne, popularly known as rosemary. The extractive solution was characterized by loss on drying, extractable matter and total phenolic and flavonoid compounds (chemical markers). The product was characterized by determination of loss on drying, size distribution, morphology, flow properties and thermal degradation and thermal behavior. The spray and spouted bed dryer performance were assessed through estimation of thermal efficiency, product accumulation and product recovery. The parameters studied were the inlet temperature of the spouting gas (80 and 150 degrees C) and the feed mass flow rate of concentrated extract relative to the evaporation capacity of the dryer, W-s/W-max (15 to 75%). The atomizing air flow rate was maintained at 20 l/min with a pressure of 196.1 kPa. The spouting gas flow rate used in the drying runs was 40% higher than the gas flow under the condition of minimum spouting. The spray drying gas flow rate was fixed at 0.0118 kg/s. Under the conditions studied, performance in the spray and spouted bed drying of rosemary extract was poor, causing high degradation of the marker compounds (mainly the phenolic compounds). Thus, process improvements are required before use on an industrial scale.

Renal toxicity caused by oral use of medicinal plants: The yacon example

Aim of the study: Yacon [Smallanthus sonchifolius (Poepp. 82 Endl.) H. Robinson, Asteraceae] is an Andean species that has traditionally been used as an anti-diabetic herb in several countries around the world, including Brazil. Its hypoglycaemic action has recently been demonstrated in normal and diabetic rats. However, studies about the safety of prolonged oral consumption of yacon leaf extracts are lacking. Thus, this work was undertaken to evaluate the repeated-dose toxicity of three extracts from yacon leaves: the aqueous extract (AE) prepared as a tea infusion; the leaf-rinse extract (LRE), which is rich in sesquiterpene lactones (STLs); and a polar extract from leaves without trichomes, or polar extract (PE), which lacks STLs but is rich in chlorogenic acids (CGAs). Materials and methods: The major classes of the compounds were confirmed in each extract by IR spectra and HPLC-UV-DAD profiling as well as comparison to standard compounds. The toxicity of each extract was evaluated in a repeated-dose toxicity study in Wistar rats for 90 days. Results: The PE was rich in CGAs, but we did not detect any STLs. The AE and LEE showed the presence of STLs. The polar extract caused alterations in some biochemical parameters, but the animals did not show signs of behavioural toxicity or serious lesions in organs. Alterations of specific biochemical parameters in the blood (creatinine 7.0 mg/dL, glucose 212.0 mg/dL, albumin 2.8 g/dL) of rats treated with AE (10,50 and 100 mg/kg) and LRE (10 and 100 mg/kg) pointed to renal damage, which was confirmed by histological analysis of the kidneys. Conclusions: The renal damage was associated with increased blood glucose levels after prolonged oral administration of the AE. This observation suggested that the hypoglycaemic effect observed after treatment for 30 days in an earlier study is reversible and was likely the result of renal injury caused by the toxicity of yacon. Because STLs were detected in both AE and LRE, there is strong evidence that these terpenoids are the main toxic compounds in the leaves of the yacon. Based on our results, we do not recommend the oral use of yacon leaves to treat diabetes. (C) 2010 Elsevier Ireland Ltd. All rights reserved.

Use of Carnobacterium maltaromaticum cultures and hydroalcoholic extract of Lippia sidoides Cham. against Listeria monocytogenes in fish model systems

Minimally processed refrigerated ready-to-eat fishes may offer health risk of severe infection to susceptible individuals due to contamination by the psychrotolerant bacterium L monocytogenes. In this work, inhibition of L monocytogenes by a plant extract and lactic acid bacteria (IAB) was studied in model fish systems kept at 5 degrees C for 35 days. For that, fillets of tropical fish ""surubim"" (Pseudoplatystoma sp.) and hydroalcoholic extract of the plant Lippia sidoides Cham. (""alecrim pimenta"") were used. Fish peptone broth (FPB), ""surubim"" broth and ""surubim"" homogenate were inoculated with combinations of L monocytogenes and bacteriocin-producing Carnobacterium maltaromaticum (C2 and A9b(+)) and non bacteriocin-producing C. maltaromaticum (A9b(-)), in the presence or absence of extract of ""alecrim pimenta"" (EAP). In all model systems, monocultures of L monocytogenes and carnobacteria reached final populations >= 10(8) CFU/ml after 35 days, except for L monocytogenes in ""surubim"" homogenate (10(4) CFU/ml). In FPB, EAP alone and combined with cultures of LAB inhibited L monocytogenes but carnobacteria without EAP were only weakly antilisterial. In ""surubim"" broth, EAP alone did not prevent L monocytogenes growth but cultures of carnobacteria combined or not with EAP inhibited L monocytogenes, with more pronounced effect being observed for C maltaromaticum C2, which produced bacteriocin. In ""surubim"" homogenate, EAP alone and combined with cultures of C. maltaromaticum A9b(-) and A9b(+) were strongly inhibitory to L monocytogenes, while C maltaromaticum C2 with EAP caused transient inhibition of L monocytogenes. No significant inhibition of L monocytogenes was observed for carnobacteria in ""surubim"" homogenate without EAP. In conclusion, it was observed that the use of EAP and cultures of carnobacteria have potential to inhibit L monocytogenes in fish systems and the applications should be carefully studied, considering the influence of food matrix. (c) 2011 Elsevier B.V. All rights reserved.

RE: Does Snus use have a harm reduction effect in Sweden?

Eletter to Tobacco Control in response to an eletter published in the same journal about whether snus (Swedish moist oral snuff) was responsible for a decline in smoking prevalence among men in Sweden.

The use of transcriptional profiles to predict adult mosquito age under field conditions

Age is a critical determinant of an adult female mosquito's ability to transmit a range of human pathogens. Despite its central importance, relatively few methods exist with which to accurately determine chronological age of field-caught mosquitoes. This fact is a major constraint on our ability to fully understand the relative importance of vector longevity to disease transmission in different ecological contexts. It also limits our ability to evaluate novel disease control strategies that specifically target mosquito longevity. We report the development of a transcriptional profiling approach to determine age of adult female Aedes aegypti under field conditions. We demonstrate that this approach surpasses current cuticular hydrocarbon methods for both accuracy of predicted age as well as the upper limits at which age can be reliably predicted. The method is based on genes that display age-dependent expression in a range of dipteran insects and, as such, is likely to be broadly applicable to other disease vectors.

Test–retest repeatability of self-reported environmental exposures in Parkinson’s disease cases and healthy controls

There is substantial disagreement among published epidemiological studies regarding environmental risk factors for Parkinson’s disease (PD). Differences in the quality of measurement of environmental exposures may contribute to this variation. The current study examined the test–retest repeatability of self-report data on risk factors for PD obtained from a series of 32 PD cases recruited from neurology clinics and 29 healthy sex-, age-and residential suburb-matched controls. Exposure data were collected in face-to-face interviews using a structured questionnaire derived from previous epidemiological studies. High repeatability was demonstrated for ‘lifestyle’ exposures, such as smoking and coffee/tea consumption (kappas 0.70–1.00). Environmental exposures that involved some action by the person, such as pesticide application and use of solvents and metals, also showed high repeatability (kappas>0.78). Lower repeatability was seen for rural residency and bore water consumption (kappa 0.39–0.74). In general, we found that case and control participants provided similar rates of incongruent and missing responses for categorical and continuous occupational, domestic, lifestyle and medical exposures.

A cross-linguistic comparison of address pronoun use in four European languages: Intralingual and interlingual dimensions

As part of a major ongoing project, we consider and compare contemporary patterns of address pronoun use in four major European languages- French, German, Italian and Swedish. We are specifically interested in two major aspects: intralingual behaviour, that is, within the same language community, and interlingual dimensions of address pronoun use. With respect to the former, we summarize our key findings to date. We then give consideration in a more preliminary fashion to issues and evidence relevant to the latter.

Continuous high-frequency turbulence and suspended sediment concentration measurements in an upper estuary

The present study details new turbulence field measurements conducted continuously at high frequency for 50 hours in the upper zone of a small subtropical estuary with semi-diurnal tides. Acoustic Doppler velocimetry was used, and the signal was post-processed thoroughly. The suspended sediment concentration wad further deduced from the acoustic backscatter intensity. The field data set demonstrated some unique flow features of the upstream estuarine zone, including some low-frequency longitudinal oscillations induced by internal and external resonance. A striking feature of the data set is the large fluctuations in all turbulence properties and suspended sediment concentration during the tidal cycle. This feature has been rarely documented.