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Harmful Substances (harmful + substance)
Selected AbstractsLiposomes for entrapping local anesthetics: A liposome electrokinetic chromatographic studyELECTROPHORESIS, Issue 9 2010Jana Lokajová Abstract Bupivacaine is a lipophilic, long-acting, amide class local anesthetic commonly used in clinical practice to provide local anesthesia during surgical procedures. Several cases of accidental overdose with cardiac arrest and death have been reported since bupivacaine was introduced to human use. Recent case reports have suggested that Intralipid (Fresenius Kabi) is an effective therapy for cardiac toxicity from high systemic concentrations of, e.g. bupivacaine, even though the mechanism behind the interaction is not fully clear yet. Our long-term aim is to develop a sensitive, efficient, and non-harmful lipid-based formulation to specifically trap harmful substances in vivo. In this study, the in vitro interaction of local anesthetics (bupivacaine, prilocaine, and lidocaine) with Intralipid or lipid vesicles containing phosphatidylglycerol, phosphatidylcholine, cardiolipin, cholesterol, and N -palmitoyl- D - erythro -sphingosine (ceramide) was determined by liposome electrokinetic chromatography. The interactions were evaluated by calculating the retention factors and distribution constants. Atomic force microscopy measurements were carried out to confirm that the interaction mechanism was solely due to interactions between the analytes and the moving pseudostationary phase and not by interactions with a stationary lipid phase adsorbed to the fused-silica wall. The heterogeneity of the liposomes was also studied by atomic force microscopy. The liposome electrokinetic chromatography results demonstrate that there is higher interaction between the drugs and negatively charged liposome dispersion than with the commercial Intralipid dispersion. [source] Characterization of Biogenic Amines and Factors Influencing Their Formation in Traditional Chinese SausagesJOURNAL OF FOOD SCIENCE, Issue 6 2010Shiling Lu Abstract:, Biogenic amines in 42 traditional Chinese sausage samples obtained from different regions were determined by HPLC. The result showed that cadaverine was the major amine, followed by tyramine and putrescine. A total of 4 groups of samples were identified on the basis of total amines by cluster analysis. Group A included samples showing low amine contents (76.5 to 220 mg/kg) and accounted for 28.5% of the sausages examined. Group B included samples with moderate amine contents (220 to 600 mg/kg) and accounted for 45.2%. Group C included 11.9% of the samples showing high total biogenic amines contents (600 to 1000 mg/kg) and group D contained 14.28% of the samples showing very high levels of biogenic amines (higher than 1000 mg/kg). High correlation coefficients were found between the total counts of,Enterobacteria,and concentrations of total biogenic amines (r,= 0.73). Sanitary quality of raw materials and the specific flora are import factors influencing biogenic amines formation in traditional Chinese sausages. Practical Application: Biogenic amines are considered potentially harmful substances to human health worldwide and are usually found in fermented sausage.Traditional Chinese sausage is one form of spontaneously fermented sausage and manufactured in small-scale plants following spontaneous fermentation. Little information, however, exists on the traditional Chinese sausage. [source] Internal loading: A new solution to an old problem in aquatic sciencesLAKES & RESERVOIRS: RESEARCH AND MANAGEMENT, Issue 1 2004Lars Håkanson Abstract Internal loading has long been regarded as an ,Achilles heel' in aquatic science and management. Internal loading is of fundamental importance in large and shallow lakes, where even low wind velocities can cause a considerable resuspension of matter deposited on the lake bed. The resuspended matter, and the chemical substances bound to the resuspended matter, will influence almost all processes in the aquatic ecosystem, such as water clarity and depth of the photic zone, and hence, primary and secondary production. If the sediments are contaminated, it will increase the concentrations of harmful substances in water and sediments and the potential ecosystem effects related to such concentrations. This paper presents an overview of the processes regulating bottom dynamic conditions in lakes (erosion, transport, accumulation), provides examples on the role of internal loading within the context of limnology and water management, and presents a new, general approach to quantify internal loading from sediments in lakes. The new approach has been critically tested, being a key factor behind the increase in predictive power of a new generation of lake models meant to be used for practical water management. Internal loading of any water pollutant depends on sedimentation. Sedimentation in this approach is presented as a function of two substance-specific variables, including the fall velocity of the carrier-particles and the particulate fraction (which, by definition, is the only fraction of a water pollutant that can settle out on the lake bed), and three generic variables, including mean depth, suspended particulate matter and ET-areas (areas of erosion and transport). On ET-areas there is, by definition, a discontinuous sedimentation of materials that settles according to Stokes' law. Basically, internal loading is the sum of advective (resuspension) and diffusive transport from the sediments. Resuspension from ET-areas is given as a function of the lake form (a new algorithm based on the volume development) and the age of ET-sediments. [source] The intestinal barrier and its regulation by neuroimmune factorsNEUROGASTROENTEROLOGY & MOTILITY, Issue 7 2010å. v. Keita Abstract Background, The ability to control uptake across the mucosa and protect from damage of harmful substances from the lumen is defined as intestinal barrier function. A disturbed barrier dysfunction has been described in many human diseases and animal models, for example, inflammatory bowel disease, irritable bowel syndrome, and intestinal hypersensitivity. In most diseases and models, alterations are seen both of the paracellular pathway, via the tight junctions, and of the transcellular routes, via different types of endocytosis. Recent studies of pathogenic mechanisms have demonstrated the important role of neuroimmune interaction with the epithelial cells in the regulation of barrier function. Neural impulses from extrinsic vagal and/or sympathetic efferent fibers or intrinsic enteric nerves influence mucosal barrier function via direct effects on epithelial cells or via interaction with immune cells. For example, by nerve-mediated activation by corticotropin-releasing hormone or cholinergic pathways, mucosal mast cells release a range of mediators with effects on transcellular, and/or paracellular permeability (for example, tryptase, TNF-,, nerve growth factor, and interleukins). Purpose, In this review, we discuss current physiological and pathophysiological aspects of the intestinal barrier and, in particular, its regulation by neuroimmune factors. [source] Assessing levels of contaminants in breast milk: methodological issues and a framework for future researchPAEDIATRIC & PERINATAL EPIDEMIOLOGY, Issue 1 2008Mary J. Renfrew Summary To assess the scale of the possible exposure by the breast-fed infant to potentially harmful substances in breast milk, methodologically robust studies are essential. Many studies in this field, however, do not report details of crucial issues such as recruitment and milk sampling. The aims of the study reported here were to develop robust methods for the study of contaminants in breast milk, and to develop a framework for future research and population monitoring. Three cohorts of women and babies were recruited by midwives from five sites in northern England. Cohort 1 (cross-sectional, n = 322) were asked to provide two milk samples, one at one week following birth and one at a subsequent time point. Cohort 2 (longitudinal, n = 54) were asked to provide five samples at specified time points over the first 12,16 weeks after birth. Cohort 3 (convenience, n = 18), mothers of babies in the Special Care Unit, were asked to donate surplus breast milk. A novel method of analysing fat concentration in small volumes was developed and tested. A randomly selected set of samples from different donors and stages of lactation was screened for organochlorine pesticide residues, polychlorinated biphenyls, dioxins/furans, phthalates and heavy metals. A total of 453 samples were donated. Cohort 3 was the least successful route of recruitment. Cohorts 1 and 2 combined were most representative of the population. Sample collection, transport and storage procedures, and the collection of data on life style and diet, were robust and acceptable to women. Midwifery involvement in recruitment was an essential component. This study offers a framework both for the conduct of future research studies, and for the establishment of regional and national monitoring mechanisms for contaminants in breast milk. Similar work on contaminants in formula as fed to babies is needed to inform risk assessment methods. [source] New Objectives of Sludge Treatment Considering a Safe Sludge RemovalCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 2 2003N. Dichtl Abstract Sewage sludge consists of valuable components such as nutrients as well as harmful substances, e.g. heavy metals. For sludge with a low concentration of pollutants, its utilization in agriculture is the best way of sludge reuse. Carbon recycling is also possible by using disintegration in combination with anaerobic degradation processes. The other important compound in sludge is phosphorus, which is a limited resource on earth. Recycling options for phosphorus are also described in the paper. A safe disposal of the residues can be achieved by using incineration. [source] | |||||||||||||