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Several classes of environmental contaminants have been claimed or suggested to possess endocrine-disrupting potency, which may result in reproductive problems and developmental disorders. In this paper the focus is on the multiple and interactive mechanisms of interference of persistent polyhalogenated aromatic hydrocarbons (PHAHs) and their metabolites(More)
Previous results from our laboratory indicated specific and competitive interactions of hydroxylated metabolites of 3,3', 4,4'-tetrachlorobiphenyl with the plasma thyroid hormone transport protein, transthyretin (TTR), in rats in vivo and with human TTR in vitro. In the present study the structural requirements for competition with thyroxine (T4) for(More)
The influence on the survival of ascitic liver tumor (TLT)-bearing mice of combined vitamins C and K3 administered before or after a single i.p. dose of 6 different cytotoxic drugs, all commonly used in human cancer therapy, was investigated. Combined i.p. administration of these vitamins produced a distinct chemotherapy-potentiating effect for all drugs(More)
In an earlier study several hydroxylated polychlorinated biphenyls (PCBs), dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) competitively displaced [125I]thyroxine (T4) from transthyretin with different potencies. Transthyretin is the major T4 transport protein in plasma of rodents. In man, however, thyroxine-binding globulin transports most of the T4 in(More)
Alkaline deoxyribonuclease (DNase) is present in human circulating serum but its physiological role and signification of its variations are still largely unknown. The present report demonstrates that between 37 degrees C and 50 degrees C, as measured in the presence of 0.25 mmol/l Ca2+ and 5 mmol/l Mg2+, serum alkaline DNase activity increases, in most(More)
A histochemical technique for detection of the in vivo induced cellular aldehydes based on the direct Schiff's reaction is reported in this paper. CCl4-intoxicated rat liver was used as an experimental model. Fresh and non-pretreated rat liver cryostat sections fixed in 10% formol calcium solution and washed in distilled water were exposed to Schiff's(More)
Supplementary introduction of a phenobarbital (PB) promotion step after the Solt and Farber procedure dramatically increases the number of phenotypically-altered hepatocytes. These hepatocytes occupy approximately 40% of the liver volume after one week of PB treatment. These areas constitute a relatively uniform cellular population with altered histological(More)
Tumorigenic effect in rat liver was increased when phenobarbital was given chronically after N-nitrosomorpholine. In these rats the liver parenchyma surrounding pre- and neo-plastic lesions demonstrated distinct, mainly centrilobular zones of hypertrophic hepatocytes with abundant eosinophilic, filamentous cytoplasm, increase in nucleic acids and decrease(More)
The majority of the known transthyretin (TTR) variants are associated with amyloidosis, but there are also variants associated with euthyroid hyperthyroxinemia and others are apparently nonpathogenic. TTR Met 119 is a nonpathogenic variant found to be frequent in the Portuguese population. Previous studies on thyroxine (T4) binding to semi-purified TTR from(More)
Serum alkaline DNase activity (SADA) was investigated in rats receiving s.c. transplants of tumor cells sensitive or resistant to chemotherapy. Serum samples from each animal were collected before transplantation, during the development of tumors and after therapy. Within a few days after transplantation of both tumor lines (sensitive or resistant), SADA(More)