We report on a detailed characterization of complex dielectric response of Na-DNA aqueous solutions by means of low-frequency dielectric spectroscopy (40 Hz-110 MHz). Results reveal two broad relaxation modes of strength 20

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A study performed over 12 months with caged mussels M. galloprovincialis in the coastal marine zone which is under the urban pressure, reveales a temporal variation of digestive gland mass which causes "biological dilution" of cytosolic metallothionein (MT) and trace metal (Cd, Cu, Zn, Fe, Mn) concentrations. The dilution effect was corrected by expressing the cytosolic MT and metal concentrations as the tissue content.

The fundamental length scales in semidilute Na-DNA aqueous solutions have been investigated by dielectric spectroscopy. The low- and the high-frequency relaxation modes are studied in detail. The length scale of the high-frequency relaxation mode at high DNA concentrations can be identified with the de Gennes-Pfeuty-Dobrynin correlation length of polyelectrolytes in semidilute solution, whereas at low DNA concentrations and in the low added salt limit the length scale shows an unusual exponent reminiscent of semidilute polyelectrolyte chains with hydrophobic backbone. The length scale of the low-frequency relaxation mode corresponds to a Gaussian chain composed of correlation blobs in the low added salt limit, and to the Odijk-Skolnick-Fixman value of the single chain persistence length in the high added salt limit.

A follow-up study of respiratory function in cotton textile workers was performed 10 yr after the original cross-sectional study (1975 to 1985). There were 35 nonsmoking female and 31 smoking male textile workers restudied from the original group of 116. The majority of those lost to follow-up had left the industry. The prevalence of byssinosis among the female workers at the time of follow-up was 15/35 (42.9%) compared with 8/35 (22.9%) at the time of the initial study (p = 0.063). For men the byssinosis prevalence at follow-up was 16/31 (51.6%) compared with 8/31 (22.9%) at the time of the initial study (p = 0.03). Similarly, the prevalence of almost all other respiratory symptoms was significantly higher at the follow-up than at the time of the initial study. Significant across-shift decrements in FEV1 and FVC were documented at both surveys. The mean annual decline in ventilatory capacity was greater than expected for both female (FVC: -0.036 +/- 0.005 L/yr; FEV1: -0.059 +/- 0.009 L/yr) and male workers (FVC: -0.059 +/- 0.008 L/yr; FEV1: -0.068 +/- 0.006 L/yr) (Mean +/- SE). The mean total airborne dust concentration measured at the time of the follow-up study was 3.95 mg/m3 with an average respirable dust concentration of 0.97 mg/m3. We conclude that continued exposure to high dust concentrations in the cotton textile industry is associated with an increasing prevalence of respiratory symptoms and progressive impairment of lung function. The increase in respiratory impairment was seen both in smokers and nonsmokers.

Cytosolic distributions of nonessential metals Cd and Tl and seven essential elements among compounds of different molecular masses were studied in the liver of brown trout (Salmo trutta) from the karstic Krka River in Croatia. Analyses were done by size exclusion high performance liquid chromatography and high resolution inductively coupled plasma mass spectrometry. Common feature of Cd and Tl, as highly toxic elements, was their distribution within only two narrow peaks. The increase of cytosolic Cd concentrations was reflected in marked increase of Cd elution within low molecular mass peak (maximum at ∼15 kDa), presumably containing metallothioneins (MTs), which indicated successful Cd detoxification in brown trout liver under studied exposure conditions. Contrary, the increase of cytosolic Tl concentrations was reflected in marked increase of Tl elution within high molecular mass peak (maximum at 140 kDa), which probably indicated incomplete Tl detoxification. Common feature of the majority of studied essential elements was their distribution within more peaks, often broad and not well resolved, which is consistent with their numerous physiological functions. Among observed associations of essential metals/nonmetal to proteins, the following could be singled out: Cu and Zn association to MTs, Fe association to storage protein ferritin, and Se association to compounds of very low molecular masses (<5 kDa). The obtained results present the first step towards identification of metal-binding compounds in hepatic cytosol of brown trout, and thus a significant contribution to better understanding of metal fate in the liver of that important bioindicator species.