301 research outputs found
Occurence of heavy metals (Hg, Cd, and Pb) and polychlorinated biphenyls in salted anchovies
No full textLevels of contaminants in fish are of particular interest because of the potential risks for consumers. Among the metals analyzed, mercury (average: 0.21 g g-1 weight wet) and cadmium (average: 0.19 g g-1 weight wet) were the most abundant, while Pb (average: 0.09 g g-1 weight wet) was present in relatively low levels. PCB levels in fillets were. Metal concentrations found in these fish species, are below the proposed limit values for human consumption
Na(+)-D-glucose cotransport by intestinal BBMVs of the Antarctic fish Trematomus bernacchii.
No full textIntestinal nutrient absorption in fish adapted to low temperature was investigated by isolating, with a Mg2+-precipitation procedure, brush-border membrane vesicles (BBMVs) from intestines of the Antarctic teleost Trematomus bernacchii. In particular, D-glucose transport was analyzed by measuring both 1) fluorescence changes of the electrical potential-sensitive dye 3,3'-diethylthiadicarbocyanine iodide. [DiS-C-2(5)] and 2) intravesicular uptake of D-[C-14]glucose. Results demonstrated that transport of D-glucose across intestinal BBMs of the Antarctic fish is stimulated by the presence of a transmembrane Na+ gradient (out > in) and was specifically inhibited by phloridzin. Furthermore, Na+-dependent D-glucose uptake was strongly enhanced by the presence of an electrical potential (inside-negative) across the membrane. There was a marked difference in temperature dependence of Na+-sugar cotransport between the Antarctic fish and temperate fish, such as the European yellow eel. Na+-dependent D-glucose uptake in T. bernacchii intestinal BBMV reached its maximal rate at -2-0 degrees C (close to fish living temperature) and was exponentially inactivated by incubation at higher temperatures. Kinetic analysis of D-glucose influx indicated the presence of a single Na+-dependent carrier process (apparent maximal carrier-mediated influx = 0.233 +/- 0.009 nmol . mg protein(-1). min(-1); apparent half-saturation constant for carrier-mediated influx - 0.157 +/- 0.026 mmol/l) and a nonsaturable transfer component (apparent diffusional permeability of membrane to the sugar = 0.233 +/- 0.016 mu l . mg protein(-1). min(-1)). The Na+-dependent carrier-mediated mechanism was specific for sugars, since it ws partially inhibited by the presence in the extravesicular medium of other monosaccharides, but not by ascorbic acid or amino acids of different types. These data suggest that in the intestine of Antarctic fish luminal D-glucose transport takes place by a specific Na+-dependent electrogenic secondary active transport working well at subzero temperatures
Na-dependent D-glucose and L-alanine transport in eel intestinal brush border membrane vesicles
No full textBrush border membrane vesicles (BBMV) were prepared from eel (Anguilla anguilla) intestine by a Mg-ethylene-glycol-bis(beta-aminoethylether)-N,N'-tetraacetic acid precipitation technique; the BBMV were enriched 16, 12, and 13 times in leucine aminopeptidase, maltase, and alkaline phosphatase activities with respect to the starting mucosal scraping. D-[3H]glucose and L-[3H]alanine transport by these vesicles was studied by a rapid filtration technique. D-Glucose uptake was stimulated by a transmembrane Na gradient but not by an identical Na gradient in the presence of phloridzin or by a choline gradient. The Na-dependent D-glucose uptake was increased by rendering the vesicle interior electrically negative, suggesting electrogenic cotransport of the sugar with Na+. Kinetic analysis gave an apparent affinity constant (Kapp) of 0.20 mM and maximal rate (Jmax) of 6.87 nmol X mg protein-1 X min-1 for glucose influx in the presence of a Na gradient. In addition, a significant apparent diffusional permeability of these membranes to glucose (1.41 microliters X mg protein-1 X min-1) was observed. L-Alanine uptake in eel BBMV was shown to occur via 1) saturable Na-dependent pathway (Kapp = 1.29 mM, Jmax = 3.61 nmol X mg protein-1 X min-1), 2) a saturable Na-independent pathway (Kapp = 0.59, Jmax = 1.49), and 3) a nonsaturable component representing apparent diffusion (permeability coefficient P = 0.57 microliter X mg protein-1 X min-1). These findings suggest that similar transport systems for glucose and alanine are found in the fish and mammalian intestinal brush border membrane
Expression of cathepsin D in malignant and in the corresponding non-malignant node-negative laryngeal samples: correlation with receptors for androgen, glucocorticoid, oestrogen and progesterone.
No full textA standard immunoradiometric technique was used to investigate the distribution of the intracellular aspartic proteinase cathepsin D in 33 malignant and in the corresponding histologically-proven non-malignant fragments obtained from lymph node negative patients suffering from larynx cancer. In both tissues the androgen, glucocorticoid, oestrogen and progesterone receptors were also assayed. Our data indicate that cathepsin D was present in both tissues, with level significantly higher (P < 0.0001) in the cancerous fragments (with a mean of 33 +/- 3.4 pmol/mg protein) than in the corresponding non-cancerous specimen (with a mean of 20.8 +/- 2 pmol/mg protein). A significant positive association (P < 0.001) between cathepsin D and PR concentration values in the cancerous larynx was observed; accordingly, tumours expressing PR had significantly (P = 0.0005) higher cathepsin D levels than the tumours which did not contain the receptor. In contrast, such a relationship was absent in the non-malignant specimens. As regards the other steroid receptors, no significant relationship between them and cathepsin D was observed. We conclude that cathepsin D may have a role also in laryngeal carcinoma and that its association with the PR could indicate a possible role of the receptor in the biology of this disease
Residui di policlorobifenili (PCBs) nel tessuto muscolare di pesci bentonici di largo consumo alimentare
No full textPolychlorinated biphenyl (PCBs) residues in the muscle tissue of Arnoglossus
laterna and Lepidorhombus whiffiagonis have been determined in order to evaluate the risk for
humans, resulting from the consumption of these marine species. PCBs concentrations were 281
μg/kg for A. laterna and 409 μg/kg for L. whiffiagonis. Isomer-specific analysis revealed a
profile dominated by hexa- and pentachlorobiphenyls. PCB dietary intake was below to 8 pg
TEQs/kg per weekly recently set by European Commission. The results obtained are not to
underestimate, considering that the weekly intake do not consider other food which might pass
these contaminants to man
Trace Metals in Pork Meat Products Marketed in Italy: Occurrence and Health Risk Characterization
No full textThis study provides valuable information on the levels of various trace metals (Pb, Cd, Hg, Zn, Cu, Cr) in meat products (baked ham, raw ham, mortadella, cured sausage, würstel, salami) from South Italy and calculates potential health risk toxicity associated with their consumption for the total population and for children. In the samples studied metal concentrations are within the permissible legal limits (Cd: 0.01–0.03 μg g−1 w.w., Hg: 0.01–0.02 μg g−1 w.w., Zn: 5.71–7.32 μg g−1 w.w., Cu: 1.08–1.21 μg g−1 w.w., Cr: 0.15–0.23 μg g−1 w.w.), except for Pb (Pb: 0.22–0.38 μg g−1 w.w.). The estimated intake values are within the provisional tolerable daily intake limits for toxic metals and recommended daily intake values for essential metals in both tested groups. The noncarcinogenic risk values of the individual metals indicate that there is no health risk, but their combined effects might constitute a potential risk for children. Furthermore, the cumulative cancer risk of all samples studied exceeds the recommended threshold risk limit (> 10−4) in both total population and children, indicating a risk of potential health problems for consumers especially for children, who are more vulnerable to toxic metal exposure
Relation of cathepsin D level to the estrogen receptor in human breast cancer
No full textSeventy-three primary human breast cancers were analyzed to assess the presence of estrogen and progesterone receptors, the p29 protein, and the total cathepsin D status. No significant relationship was found between cathepsin D concentration and the presence of ER or PR, either by Fisher's exact test or Spearman's rank correlation (P greater than 0.1). However, a significant association was found between cathepsin D and p29 (Fisher's exact test, P less than 0.001) and between cathepsin D and steroid receptor status in samples expressing both estrogen and progesterone receptors (positive by steroid binding assay and enzyme immunoassay) (P less than 0.05). This association was more significant in tissues expressing estrogen and progesterone receptors as well as p29 (P less than 0.001). In contrast, cathepsin D synthesis was not related to tumor size, lymph node involvement, or patient's age (P greater than 0.05). Steroid receptors and cathepsin D were also assayed in samples of non-malignant tissue from 16 mastectomies; there was a significantly higher relative concentration of cathepsin D in the malignant specimens (Student's t-test, P less than 0.001)
Functional and structural characterization of the zebrafish Na+-sulfate cotransporter 1 (NaS1) cDNA and gene (slc13a1)
No full textSulfate plays an essential role during growth, development and cellular metabolism. In this study, we characterized the function and structure of the zebrafish (Danio rerio) Na+-sulfate cotransporter 1 (NaS1) cDNA and gene (slc13a1). Zebrafish NaS1 encodes a protein of 583 amino acids with 13 putative transmembrane domains. Expression of zebrafish NaS1 protein in Xenopus oocytes led to Na+-sulfate cotransport, which was significantly inhibited by thiosulfate, selenate, molybdate, and tungstate. Zebrafish NaS1 transport kinetics were: V(max) = 1,731.670 +/- 92.853 pmol sulfate/oocyte.hour and K(m) = 1.414 +/- 0.275 mM for sulfate and V(max) = 307.016 +/- 32.992 pmol sulfate/oocyte x hour, K(m) = 24.582 +/- 4.547 mM and n (Hill coefficient) = 1.624 +/- 0.354 for sodium. Zebrafish NaS1 mRNA is developmentally expressed in embryos from day 1 postfertilization and in the intestine, kidney, brain, and eye of adult zebrafish. The zebrafish NaS1 gene slc13a1 contains 15 exons spanning 8,716 bp. Characterization of the zebrafish NaS1 contributes to a greater understanding of sulfate transporters in a well-defined genetic model and will allow the elucidation of evolutionary and functional relationships among vertebrate sulfate transporters
Co-expression of thymidine kinase and cathepsin D in 200 primary breast carcinomas.
No full textWe assayed thymidine kinase (TK) and cathepsin D (Cath-D) in 200 breast carcinomas and we found that they were significantly correlated. This correlation was present in lymph node positive rumours. in G2 and G3, in T1 and in invasive ductal carcinomas. In addition, TK and Cath-D did not correlate with oestrogen receptor (ER) and progesterone receptor (PgR) status. We conclude that the relationship between Cath-D and TK may indicate a tumour population of high proliferation activity and invasiveness potential, related to a more aggressive phenotype. whose identification may be useful in defining prognosis
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