Thyroid hormone autoantibodies: are they a better marker to detect early thyroid damage in patients with hematologic cancers receiving tyrosine kinase inhibitor or immunoregulatory drug treatments?

BACKGROUND

Unlike cytotoxic agents, novel antineoplastic drugs can variably affect thyroid function and so impair patient outcomes. However, the widely used standard thyroid tests have demonstrated low sensitivity for detecting early thyroid damage that leads to dysfunction of the gland. To find a more reliable thyroid marker, we assessed the presence of antibodies binding thyroid hormones (thAbs) in a cancer population undergoing potentially thyrotoxic treatment.

METHODS

From April 2010 to September 2013, 82 patients with hematologic malignancies treated with tyrosine kinase inhibitors or immunoregulatory drugs were recruited. Healthy volunteers (n = 104) served as control subjects. Thyroid function, autoimmunity tests, thAbs, and thyroid sonography were assessed once during treatment.

RESULTS

Overall, thAb positivity was recorded in 13% of the entire cohort. In most cases, the thAbs were of a single type, with a predominance of T3 immunoglobulin G. More specifically, thAbs were detected in 11 cancer patients; and abnormal levels of thyroid-stimulating hormone, thyroglobulin antibody, and thyroperoxidase antibody were detected in 6 (p = 0.05), 0 (p = 0.0006), and 2 cancer patients (p = 0.001) respectively. Ultrasonographic alterations of the thyroid were observed in 12 cancer patients. In contrast, of the 104 healthy control subjects, only 1 was positive for thAbs (1%).

CONCLUSIONS

We have demonstrated for the first time that thAbs are a reliable marker of early thyroid dysfunction when compared with the widely used standard thyroid tests. A confirmatory prospective trial aiming at evaluating thAbs at various time points during treatment could clarify the incidence and timing of antibody appearance.

Different effects of cGMP and cAMP in the intestine of the European eel, Anguilla anguilla

The regulation of salt absorption in the sea water eel intestine was studied by evaluating the effects of theophylline, 8 Br cyclic adenosine monophosphate, 8 Br cyclic guanosine monophosphate, atriopeptin III, porcine vasoactive intestinal peptide and prostaglandin E1 on the short-circuit current, the transepithelial voltage difference and conductance and on the dilution potentials. It was shown that theophylline increased the transepithelial conductance and reduced the magnitude of the dilution potentials, indicating that the drug increases the anion conductance of the tight junctions. In addition its inhibitory effect on short-circuit current and transepithelial voltage difference suggests that theophylline also affects the transcellular transport mechanisms. It was shown that 8 Br cyclic guanosine monophosphate and 8 Br cyclic adenosine monophosphate affect transcellular mechanisms underlying C1- transport since both compounds reduced short-circuit current and transepithelial voltage difference; however, cyclic adenosine monophosphate is less effective since unlike cyclic guanosine monophosphate, even at maximal concentration, it was not able to completely abolish transepithelial voltage difference and short-circuit current. The effects of cyclic guanosine monophosphate and cyclic adenosine monophosphate were not additive even if cyclic guanosine monophosphate may produce further inhibition of ion transport in 8 Br cyclic adenosine monophosphate-treated tissues. In addition, cyclic guanosine monophosphate but not cyclic adenosine monophosphate reduced the magnitude of the dilution potentials, suggesting that cyclic guanosine monophosphate acts also on the paracellular pathway. Rat atriopeptin III, a peptide known to increase cyclic guanosine monophosphate cellular levels, behaved like 8 Br cyclic guanosine monophosphate since it lowered the dilution potentials and reduced short-circuit current and transepithelial voltage difference to near zero values, suggesting that the hormone modulates both paracellular and transcellular transport mechanisms, probably acting on the Na-K-2Cl cotransport. Agents acting via cyclic adenosine monophosphate, like porcine Basoactive intenstinal peptide and prostaglandin, behaved like 8 Br cyclic adenosine monophosphate. They were less effective in inhibiting ion transport and did not interfere with the paracellular pathway.

Some aspects of zinc transport across eel (Anguilla anguilla) red blood cell membranes

Zinc movement across eel and human red blood cell membranes was measured by atomic absorption spectrophotometry. It was observed that: 1) In human red blood cells zinc uptake is twice as rapid as in fish red blood cells over a temperature range of 10-40 degrees C. The low rate of zinc uptake in eel red blood cell may be simply the side effect of different surface area to volume ratios for the differences in cell size or, it may be due to the low permeability of bicarbonate through the red blood cell membranes. 2) Zinc uptake measured in eel and human red blood cells treated and untreated with external trypsin shows different features. The zinc uptake was reduced by about 40% in treated eel red blood cells with respect to the total uptake of untreated red blood cells. Human red blood cells treated and untreated with trypsin do not show any differences in the amount of zinc transported. 3) In fish red blood cells, zinc uptake in NaNO3 medium is markedly reduced, compared with that measured in NaCl medium. The [Zn2+i slightly increases in the presence of bicarbonate. In human red blood cells in NaNO3 medium the zinc uptake is strongly reduced and the presence of bicarbonate marginally increases the zinc influx. 4) In eel red blood cells there seem to be two independent pathways for zinc uptake: one DIDS-sensitive and the other DIDS-insensitive. DIDS 10 microM inhibits only 64% of the total zinc transported. Increasing the DIDS concentration did not give more inhibition. In human red blood cells only one DIDS-sensitive pathway for zinc transported seems to exist, because, 2, 5 microM DIDS inhibits 97% of zinc uptake.

The inhibitory effect of anthranilate derivatives on HCO3-/Cl- exchange in red blood cells of human, pigeon and trout

All ten of anthranilate derivatives were found to be inhibitors of HCO3-/Cl- exchange in human, trout and pigeon red blood cells. The individual l50 values covered a range of 2-3 orders of magnitude for human, trout and pigeon RBCs. The results obtained confirm that the anion transporting region of the band 3 protein in human, trout and pigeon red blood cells are highly preserved even though the RBCs belong to animals living in entirely different habitats. However, in spite of the general similarities, significant differences between human trout and pigeon red blood cells could be observed. They could be attributed to differences of the hydrophobic character of the various probes.