Polychlorinated biphenyls and organochlorine pesticide levels in tissues of Caretta caretta from the Adriatic Sea.

We detected concentrations of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCs) in the liver, muscle, and fat of 11 loggerhead sea turtles Caretta caretta from the central and southern Adriatic Sea. All samples contained PCBs at various concentrations, with Congener 138 (28%), 153 (27%), and 180 (32%) dominating the congener composition of the tissues. The dioxin-like congener (118, 13%) was detected in all tissues analyzed. The lower-chlorinated PCBs were not detected. The average of the total PCB concentrations, expressed in nanograms per gram wet weight, was 459.6 ng g(-1) in fat, 82.9 ng g(-1) in liver, and 5.8 ng g(-1) in muscle. Among 13 organochlorine pesticides for which analyses were conducted, 4 were detected: p,p'-DDE (57%); p,p'-DDD (16%); and p,p'-DDT and o,p'-DDT (27%). Spatial differences were found among OC concentrations in loggerheads from the central and southern Adriatic Sea. The only samples containing detectable concentrations of p,p'-DDT and o,p'-DDT were from the southern area.

Transthyretin fibrillogenesis entails the assembly of monomers: a molecular model for in vitro assembled transthyretin amyloid-like fibrils.

Extracellular accumulation of transthyretin (TTR) variants in the form of fibrillar amyloid deposits is the pathological hallmark of familial amyloidotic polyneuropathy (FAP). The TTR Leu55Pro variant occurs in the most aggressive forms of this disease. Inhibition of TTR wild-type (WT) and particularly TTR Leu55Pro fibril formation is of interest as a potential therapeutic strategy and requires a thorough understanding of the fibril assembly mechanism. To this end, we report on the in vitro assembly properties as observed by transmission electron microscopy (TEM), atomic force microscopy (AFM) and quantitative scanning transmission electron microscopy (STEM) for both TTR WT fibrils produced by acidification, and TTR Leu55Pro fibrils assembled at physiological pH. The morphological features and dimensions of TTR WT and TTR Leu55Pro fibrils were similar, with up to 300 nm long, 8 nm wide fibrils being the most prominent species in both cases. Other species were evident; 4-5 nm wide fibrils, 9-10 nm wide fibrils and oligomers of various sizes. STEM mass-per-length (MPL) measurements revealed discrete fibril types with masses of 9.5 and 14.0(+/-1.4) KDa/nm for TTR WT fibrils and 13.7, 18.5 and 23.2(+/-1.5) kDa/nm for TTR Leu55Pro fibrils. These MPL values are consistent with a model in which fibrillar TTR structures are composed of two, three, four or five elementary protofilaments, with each protofilament being a vertical stack of structurally modified TTR monomers assembled with the 2.9 nm axial monomer-monomer spacing indicated by X-ray fibre diffraction data. Ex vivo TTR amyloid fibrils were examined. From their morphological appearance compared to these, the in vitro assembled TTR WT and Leu55Pro fibrils examined may represent immature fibrillar species. The in vitro system operating at physiological pH for TTR Leu55Pro and the model presented for the molecular arrangement of TTR monomers within fibrils may, therefore, describe early fibril assembly events in vivo.

Capture assay for specific IgE. An improved quantitative method.

A capture assay for the measurement of specific IgE in the serum of allergic patients is described, using monoclonal anti-human IgE (coated to the wells of a microtiter plate) and biotinylated allergens in solution. In a single incubation, IgE is bound to the solid phase through the Fc fragment and biotinylated allergens react with their specific IgE Fab regions, if present. In a second step, streptavidin-HRP conjugate is added to reveal the amount of biotin fixed on the solid phase. Quantitative determinations are obtained by comparison with a standard curve of total IgE incubated with a biotinylated monoclonal anti-IgE, complementary to the one employed as capture antibody. The assay is unaffected by allergen-specific IgG, shows good intra- and interassay reproducibility and is linear over a wide range of specific IgE concentrations. The method could be used with a wide range of different allergens.

Biotinylated recombinant interleukin-2. A tool for research on the interleukin-2 receptor.

Recombinant interleukin-2 was biotinylated using a N-hydroxyl-succinimidyl [3H]biotin ester. The biotinylated lymphokine retained full binding and growth-promoting activities when assayed on the interleukin-2-dependent murine cell line HT-2. In preliminary studies, biotinylated interleukin-2 was used in conjunction with immunogold staining to demonstrate cell surface interleukin-2 receptors using both light and electron microscopy techniques. In addition, with rabbit anti-biotin antibodies, biotin-interleukin-2 was able to precipitate the 55 kDa IL-2 receptor from murine HT-2 cells. Thus, biotin-interleukin-2 represents a useful, non-radioactive tool for studying the structure and function of the interleukin-2 receptor.

Stability and effectiveness of chlorine disinfectants in water distribution systems.

A test system for water distribution was used to evaluate the stability and effectiveness of three residual disinfectants--free chlorine, combined chlorine, and chlorine dioxide--when challenged with a sewage contaminant. The test distribution system consisted of the street main and internal plumbing for two barracks at Fort George G. Meade, MD. To the existing pipe network, 152 m (500 ft) of 13-mm (0.5 in.) copper pipe were added for sampling, and 60 m (200 ft) of 2.54-cm (1.0 in.) plastic pipe were added for circulation. The levels of residual disinfectants tested were 0.2 mg/L and 1.0 mg/L as available chlorine. In the absence of a disinfectant residual, microorganisms in the sewage contaminant were consistently recovered at high levels. The presence of any disinfectant residual reduced the microorganism level and frequency of occurrence at the consumer's tap. Free chlorine was the most effective residual disinfectant and may serve as a marker or flag in the distribution network. Free chlorine and chlorine dioxide were the least stable in the pipe network. The loss of disinfectant in the pipe network followed first-order kinetics. The half-life determined in static tests for free chlorine, chlorine dioxide, and combined chlorine was 140, 93, and 1680 min.

Immunoelectron microscopy of different forms of glomerulonephritis in routine biopsy material.

Renal biopsies were investigated of patients with IgA or membraneous glomerulonephritis or with systemic lupus erythematosus by light microscopy, electron microscopy, light microscopic immunohistology and by immunoelectron microscopy using the post-embedding technique applied to LR-White embedded tissue. Aim of the study was to explore whether immunoelectron microscopy is reproduced on routine biopsy material and in accordance with light microscopic immunohistological findings. The study shows that immunoelectron microscopy can be applied to routine biopsy material and gives reproducible results. The applied method proved to be reliable, and, hence, routine biopsy material may be used for further studies concerning subcellular mechanisms in immunocomplex deposition and removal.

Levels of polychlorinated biphenyls and organochlorine pesticides in some edible marine organisms from the Central Adriatic Sea.

Concentrations of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCs) were found in tissue of marine organisms such as Mediterranean mussel, Norway lobster, red mullet, common cuttle-fish, European flying squid, European anchovy, European pilchard and Atlantic mackerel, coming from two sites along the Abruzzo coast of the Adriatic Sea. Species were selected due to their habitat, trophic level, feeding behaviour and their use in the Italian diet. Mussels, filter feeder and sedentary organisms, were used in order to test water pollution whereas Norway lobster and red mullet (benthic fish) were used in order to test sediment pollution. The concentration of ?PCBs exceeded that of ?OCs in the samples analysed. The highest concentrations of ?PCBs (1415 ng/g lipid weight) and ?OCs (507 ng/g lipid weight) were found in pilchard while the lowest concentrations of the same pollutants were found in cephalopods. Our results have shown that species such as anchovy, pilchard and mackerel, were the most polluted due to their location at the last level of the trophic chain. All samples contained different concentrations of PCBs and among these, congeners 153 and 138 were the most representative. Among the OCs, except for the cuttle-fish, the highest concentrations were found for p,p(')-DDE and p,p(')-DDD that are metabolite of DDT. The prevailing DDE presence, compared to DDT (high DDE/DDT ratio), suggested that the biotransformation rate of pollutants was very efficacious in fish and above all in crustaceans. Results have also been interpreted in terms of geographical distribution and organisms' biological cycle. None of the samples analysed exceeded the tolerance limits established by the OCs Italian legislation.

Markers of eosinophilic inflammation and risk prediction in patients with coronary artery disease.

BACKGROUND: The eotaxin family comprises three distinct peptides (eotaxin, eotaxin-2 and eotaxin-3) which have been implicated in eosinophilic inflammation. In vitro and clinical studies suggest that eotaxins could play a role in vascular inflammation, but no data are available on their prognostic significance in patients with angiographically documented coronary artery disease (CAD). MATERIALS AND METHODS: Baseline plasma samples were obtained from 1014 patients with documented CAD. We tested the predictive effect of markers of eosinophilic inflammation and C-reactive protein (CRP) on death from cardiovascular causes and nonfatal myocardial infarction over a 2.7-4.1-year follow-up period. RESULTS: Unexpectedly, lower eotaxin-3 concentrations were observed in patients with adverse cardiovascular events, whereas both eotaxin and eotaxin-2 showed no association with risk. After adjustment for most potential confounders, patients in the upper-quartile of eotaxin-3 levels had a 0.42 hazard-ratio (95% CI, 0.29-0.61, P < 0.001) for adverse events compared with subjects in the lower-quartile. The highest risk of future cardiovascular events was observed in subjects with combined elevation of CRP and reduction of eotaxin-3; 4.4 hazard-ratio (95% CI, 2.1-9.5, P < 0.001). Importantly, receiver-operating-characteristic curves analysis suggested a superior prognostic value of eotaxin-3 compared with CRP for predicting cardiac events in patients with CAD. CONCLUSIONS: Low levels of eotaxin-3 are an independent predictor of future adverse cardiovascular events in patients with CAD and may be useful for risk stratification.

Disinfecting capabilities of oxychlorine compounds.

The bacterial virus f2 was inactivated by chlorine dioxide at acidic, neutral, and alkaline pH values. The rate of inactivation increased with increasing pH. Chlorine dioxide disproportionation products, chlorite and chlorate, were not active disinfectants. As chlorine dioxide solutions were degraded under alkaline conditions, they displayed reduced viricidal effectiveness, thereby confirming the chlorine dioxide free radical as the active disinfecting species.

Kinetics and mechanism of bacterial disinfection by chlorine dioxide.

Survival data are presented for a fecal strain of Escherichia coli exposed to three concentrations of chlorine dioxide at four temperatures. Chick's first-order reaction equation is generalized to a pseudo nth-order model. Nonlinear least squares curve-fitting of the survival data to the nth order model was performed on an analogue computer. The data were observed to follow fractional order kinetics with respect to survival concentration, with an apparent activation energy of 12,000 cal/mole. Initial experiments support the thesis that the mechanism of chlorine dioxide kill occurs via disruption of protein synthesis.

Oligomeric structure of the Bacillus subtilis cell division protein DivIVA determined by transmission electron microscopy.

DivIVA from Bacillus subtilis is a bifunctional protein with distinct roles in cell division and sporulation. During vegetative growth, DivIVA regulates the activity of the MinCD complex, thus helping to direct cell division to the correct mid-cell position. DivIVA fulfils a quite different role during sporulation in B. subtilis when it directs the oriC region of the chromosome to the cell pole before asymmetric cell division. DivIVA is a 19.5 kDa protein with a large part of its structure predicted to form a tropomyosin-like alpha-helical coiled-coil. Here, we present a model for the quaternary structure of DivIVA, based on cryonegative stain transmission electron microscopy images. The purified protein appears as an elongated particle with lateral expansions at both ends producing a form that resembles a 'doggy-bone'. The particle mass estimated from these images agrees with the value of 145 kDa measured by analytical ultracentrifugation suggesting 6- to 8-mers. These DivIVA oligomers serve as building blocks in the formation of higher order assemblies giving rise to strings, wires and, finally, two-dimensional lattices in a time-dependent manner.