Content of PAHs in soil of a hazel orchard depending on the method of weed control.

PAHs belong to persistent organic pollutants (POPs) found in the natural environment. They eventually accumulate in the highest quantities in soil. The purpose of this study has been to determine quantities of PAHs in soil depending on the method applied to control weeds in rows of a 4-year plantation of hazel (mulch fabric, bark chips, sawdust, manure compost, bare fallow, chemical fallow, grass sward). The highest concentration of PAHs (16 PAHs) was found in soil kept as bare fallow. The second most abundant concentration of these compounds was determined in soil under grass sward, followed by soil under sawdust, chemical fallow, and fabric. Less of these compounds accumulated in soil mulched with bark chips. The best method for protection of orchard soil against the accumulation of unwanted and toxic PAHs was mulching with manure compost. In most cases, lower concentrations of PAHs (total 16) were found in the subsoil (30-60 cm) than in the topmost soil layer, except the soil covered with mulch fabric, where fourfold more PAHs accumulated.

Chaperone-mediated autophagy components are upregulated in sporadic inclusion-body myositis muscle fibres.

AIMS: Sporadic inclusion-body myositis (s-IBM) is an age-associated degenerative muscle disease. Characteristic features are muscle-fibre vacuolization and intramuscle-fibre accumulations of multiprotein aggregates, which may result from the demonstrated impairments of the 26S proteasome and autophagy. Chaperone-mediated autophagy (CMA) is a selective form of lysosomal degradation targeting proteins carrying the KFERQ motif. Lysosome-associated membrane protein type 2A (LAMP2A) and the heat-shock cognate protein 70 (Hsc70) constitute specific CMA components. Neither CMA components nor CMA activity has been studied in normal or disease human muscle, to our knowledge. METHODS: We studied CMA components by immunocytochemistry, immunoblots, real-time PCR and immunoprecipitation in: (a) 16 s-IBM, nine aged-matched normal and nine disease control muscle biopsies; and (b) cultured human muscle fibres (CHMFs) with experimentally inhibited activities of either the 26S proteasome or autophagy. RESULTS: Compared with age-matched controls, in s-IBM muscle, LAMP2A and Hsc70 were on a given transverse section accumulated as aggregates in approximately 5% of muscle fibres, where they (a) colocalized with each other and α-synuclein (α-syn), a CMA-targeted protein; and (b) were bound to each other and to α-syn by immunoprecipitation. By immunoblots, LAMP2A was increased sevenfold P < 0.001 and Hsc70 2.6-fold P < 0.05. LAMP2A mRNA was increased 4.4-fold P < 0.001 and Hsc70 mRNA 1.9-fold P < 0.05. In CHMFs inhibition of either the 26S proteasome or autophagy induced CMA, evidenced by a significant increase of both LAMP2A and Hsc70. CONCLUSIONS: Our study demonstrates, for the first time, up-regulation of CMA components in s-IBM muscle, and it provides further evidence that altered protein degradation is likely an important pathogenic aspect in s-IBM.

Myostatin and its precursor protein are increased in the skeletal muscle of patients with Type-II muscle fibre atrophy.

Preferential atrophy of Type-II muscle fibres occurs in several clinical situations, including cachexia, muscle disuse, chronic glucocorticoid treatment, remote neoplasia, and sometimes as an aspect of recent-denervation. For the patient, the Type-II atrophy itself might be unfavourable (as a glucocorticoid side-effect) or favourable (survivalistic via the muscle-alanine liver-gluconeogenesis pathway in starvation). The cellular mechanisms underlying Type-II fibre atrophy are unclear. Myostatin (Mstn) is physiologically a negative regulator of muscle mass and strength. In this study we evaluated a possible role of Mstn in Type-II fibre atrophy in human muscle. Mstn and Mstn precursor protein (MstnPP) were studied in 10-muscle biopsies containing Type-II fibre atrophy and in 17 disease and normal control muscle biopsies. When comparison was made with normal control fibres, we found the following: 1) by immunocytochemistry, diffusely increased Mstn/MstnPP in the atrophic Type-II muscle fibres; 2) by immunoblots, Mstn/MstnPP increased individually; 3) by RT-PCR, no increase in MstnPP mRNA. In conclusion, our results a) suggest that Mstn/ /MstnPP might play a role in the pathogenic cascade of Type-II muscle fibre atrophy; b) broaden our previously-described associations of Mstn in human muscle pathology, and c) could possibly lead to clinical prevention when Type-II muscle fibre atrophy is unfavourable, for instance in glucocorticoid therapy.

The age-related differences in obese and fatty acid synthase gene expression in white adipose tissue of rat.

To determine if the age-dependent increase of adiposity is directly related to altered obese (ob) and fatty acid synthase (FAS) gene expression, we assessed an adiposity index, leptin and FAS mRNA levels, FAS activity in perirenal adipose tissue and serum leptin concentration in rats aged 1, 2, 3, 6 and 20 months. The results indicate that there are two distinct phases of changes in perirenal white adipose tissue leptin mRNA level and serum leptin concentration. The first phase, between 1 and 3 months of the animals' lives, was characterized by a strong positive correlation between adiposity index and leptin mRNA level as well as serum leptin concentration. In the second phase (over 3 months) no significant changes of leptin mRNA and serum concentration occurred. A close correlation between the age-induced increase of leptin mRNA abundance and serum leptin concentration and the age-induced suppression of FAS gene expression in the same tissue was observed. This suggests that the changes of FAS gene expression occur in response to serum leptin concentration and that in mature rats the high level of ob gene expression and consequently the high leptin concentration protect the white adipose tissue cells against fat overload by two independent mechanisms: (a) preventing an increase of food intake through the leptin action on the hypothalamus; (b) inhibiting FAS gene expression and consequently decreasing the rate of lipogenesis.