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Screening whole effluent toxicity tests are cost/effective methods for detecting the presence of toxic concentrations of unknown pollutants, but the application must solve the problem associated with the effect of high and variable concentrations of nutrients in the effluent on the results of algal toxicity tests. This work proposes a cost/effective test, based on three dilution levels measured at a single point time and a discriminant model for establishing if this kind of complex samples, with difficult interpretation of dilution-response curves, should be considered toxic to algae. This procedure identified properly around 85% of the samples considered toxic by expert judgement. [ABSTRACT FROM AUTHOR]

In this work we have developed a cost-effective method for the analysis of methyl mercury (MeHg) in seawater fish muscle. The novelty of this method lies in the use of microwave-assisted extraction with acidic solution (HCl), addition of toluene, and subsequent extraction with cysteine acetate solution where only MeHg is present because of its affinity for cysteine groups. MeHg in cysteine phase and total mercury in the homogenate muscle tissue were determined using a direct Hg analyzer (DMA-80). Validation, precision, and accuracy of the method were evaluated and monitored with a tuna fish certified reference material (CRM 463) containing MeHg. [ABSTRACT FROM AUTHOR]

Introduction: Serratia marcescens is widely distributed in nature, and has emerged in the last years as an important nosocomial pathogen. The organism may also be found in subgingival biofilm in periodontitis patients. This study aimed to verify the subgingival prevalence of S. marcescens in different periodontal conditions and to evaluate whether the oral cavity would harbor strains similar to those causing infectious diseases. Methods: The subgingival occurrence of S. marcescens was determined in 334 subjects. The phenotypic and genotypic diversity of 23 isolates from subgingival biofilm, 22 from extra-oral infections and 10 environmental strains, was compared by prodigiosin production, O and H serotyping and genotyping using polymorphic GC-rich repetitive sequences–polymerase chain reaction. Results: S. marcescens was found more frequently in severe periodontitis patients (4.1%) than in gingivitis (3.2%) and healthy subjects (2.5%), but these differences were not statistically significant. Analysis of serotype distribution, prodigiosin production, and genotyping revealed that environmental strains were markedly different from most human isolates, either oral or extraoral. Conclusion: These data suggest that S. marcescens isolates from subgingival biofilm are not just contaminants from the environment, but that the oral cavity may act as a reservoir of strains able to promote human infections. However, further studies are needed to elucidate the role of this bacterium in the pathogenesis of periodontal diseases. [ABSTRACT FROM AUTHOR]

This article presents a study which deals with toxicity identification evaluation of organic pollutants based on solid-phase micro-extraction and gas chromatography/mass spectrometry. Since 1989, solid phase micro-extraction (SPME) is being applied to organic characterization of all kinds of environmental samples, generally linked to gas chromatography. It has also been used to assess aquatic toxicity in complex mixtures. SPME has been applied successfully in sewage characterization and could be applied in toxicity identification evaluation protocols representing a cost/effective tool.

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The article cites a study on the effect of antimicrobial pharmaceuticals on the aquatic plant lemna minor. Lemna minor was collected in the Jarama River in Madrid, Spain and cultured in a laboratory for over 3 years. The toxicity of both antimicrobials to the unicellular algae Chlorella vulgaris was also studied. Oxytetracycline showed a similar toxicity for lemna than for Chlorella. Results of the study suggested that a single and practical parameter, number of green fronds, can be sufficient for summarising the outcome of this assay in a way compatible with other standard tests.

This article presents information on Linear Alkyl Benzene (LAB) which is the parent material for manufacturing anionic surfactant Linear Alkylbenzene Sulfonate (LAS) that is used in commercial detergent formulations. During the sulfonation reaction a small percentage, currently less than 1 percent, of LAB remains unsulfonated and is found as impurity in LAS. Moreover, LAB toxicity to aquatic organisms is expected to be related to non-polar narcosis, and therefore associated to the total body burden, while the only available information on the toxicity of LAB to aquatic organisms focuses on waterborne exposures.

Boron neutron capture therapy (BNCT) is based on the nuclear reaction that occurs when the stable isotope, Boron-10, is irradiated with low-energy thermal neutrons to yield ionizing Helium and Lithium ions that are highly damaging and usually lethal to cells. The successful treatment of cancer by BNCT requires the selective concentration of Boron-10 within malignant tumours. Liposomes have been used as therapeutic compound delivery vehicles for in vivo application, including several anticancer agents. The ability of the boroncontaining compound, o-carboranylpropylamine chloride, to accumulate within unilamellar liposomes in response to a transmembrane pH gradient is evaluated. Characterization of the systems obtained is performed for conventional and polyethylene glycol (PEG)-modified (stealth) liposomes, in terms of lipid and CPA contents, vesicle size and stability in detergent solutions. Results demonstrate that CPA loading and vesicle stability can be controlled by the experimental procedure. The loading of CPA into liposomes with average diameters of 100nm is estimated at 13000 molecules per vesicle for the most stable systems. CPA toxicity to normal human peripheral blood lymphocytes and to adherent glioblastoma multiforme SK-MG-1 cells in vitro is observed to decrease as a result of the entrapment of CPA in liposomes. [ABSTRACT FROM AUTHOR]

The article studies the levels of several metals in sediments from shrimp aquaculture areas in Nicaragua and Honduras. Similar ranges were obtained among sampling sites from both areas with iron concentrations from 15.5 to 43.5 g/kg, manganese from 197 to 694 μg/g, zinc from 59.8 to 122.4 μg/g, and copper from 26 to 51.2 μg/g. Cadmium ranging from 0.03 to 0.095 μg/g and mercury from 0 to 0.15 μg/g have the lowest values with lithium having the greatest fluctuation. River runoff and ship-related inputs are the main source of metals in marine sediments in addition to direct disposal of solid or liquid wastes. The levels of metals in sediments from the Gulf of Fonseca's shrimp culture area were lower than those in other parts of the world.

The article focuses on the metal concentrations in shrimps accumulated from the Gulf of Fonseca in Central America. Four intensive culture areas were selected in Nicaragua while three were chosen from Honduras. The shrimps were frozen at -20 degrees Celsius and the edible portions were analyzed by atomic absorption spectrophotometry. The results show average metal concentrations in shrimps samples and the most abundant elements found were iron, zinc, and copper. Metal concentrations detected in shrimps from the Gulf of Fonseca were also presented and compared to the different shellfish species of commercial value. The low metal levels and the absence of important correlations between sediments and shrimp metal concentration indicate that the degree of contamination is low.

The article presents a study regarding a field event on the lethal poisoning of rainbow trout (Oncorhynchus mykiss), Atlantic salmon (Salmo salar), and coho salmon (Oncorhynchus kisutch) by sulfide in a Spanish fish farm. The study uses a histopathological study and ecotoxicological index to quantify the environmental impact on the macrobenthic community. Results show sulfide poisoning of salmonid fish in a well-aerated river unexposed to industrial or main urban waste dumping.

The difference between the methods of amylase determination lies the use of different substrates and in the final product of reaction. There are three methods in use: 1) amyloclastic method (determination of decreases in iodine-starch color); 2) saccharogenic method (determination of increases of reducing substances); 3) chromogenic method (splitting of semisynthetic substrates). Each method determines a certain set of amylolytic enzymes splitting glycogen or starch and differs from each other by the quantity of substrates being split, the quantity of the final product as well as the specific isoenzyme tested. Moreover, the groups of enzymes determined by the different methods differ in availability and properties of enzyme inhibitors. Amylolytic enzymes (pancreatic) determined by splitting semi-synthetic substrates have minimal inhibitors and are demonstrated by increases of serum amylase as seen in acute and exacerbation of chronic pancreatitis. Amylases possessing inhibitors may be of significance in diagnosing of chronic pancreatitis. Increase of amylase activity in blood indicates only the acuteness of the process but not the severity of the disease. Such increases can be observed as well in acute or active processes in the hepato-biliary tract, e.g., active liver cirrhosis, acute or exacerbation of chronic cholecystitis, and in patients after cholecystectomy. Two amylase inhibitors were determined in serum: in diluted serum (DAI) and in serum incubated with trypsin (TAI). Amylase inhibitors increase in patients with chronic pancreatitis. In exacerbation of pancreatitis the inhibitors are significantly depressed. [ABSTRACT FROM AUTHOR]

Examines the possible effect of manipulating protein intake and steroid levels on serum trypsin and trypsin inhibitor concentration in patients with chronic pancreatitis and Addison's disease. Method used to determine serum amylase activity; Average serum amylase and trypsin activity data in healthy subjects and in patients with chronic pancreatitis before and after a protein diet; Effect of anabolic steroid administration to patients with chronic pancreatitis.