Effects of thyroid hormone withdrawal on natriuretic peptides during radioactive iodine therapy in female patients with differentiated thyroid cancer

Objective: We aimed to investigate the effects of thyroid hormone withdrawal on N-terminal prohormone forms of atrial natriuretic peptide (NT-proANP) and brain natriuretic peptide (NT-proBNP) during radioiodine therapy in female patients with differentiated thyroid cancer (DTC).

Methods: Serum concentrations of thyroid-stimulating hormone (TSH), free triiodothyronine (FT3), NT-proANP and NT-proBNP were measured in 51 female patients with DTC (48.7?±?4.2 years) at three time-points: day of radioiodine therapy (t1 – under acute hypothyroidism), 5 days after radioiodine (t2 – under acute hypothyroidism) and 3 months after radioiodine (t3 – under TSH suppression). Thirty healthy euthyroid women served as controls (42.8?±?5.6 years).

Results: At t1/t2/t3, median NT-proANP was 5.2/1.7/487?pmol/L vs. 297.7?pmol/L in control group (p?p?p?r?=?0.38, p?=?0.005), NT-proANP/NT-proBNP ratios (r?=?0.47, p?=?0.001), heart rate (r?=?0.39, p?=?0.005), and negatively with mean arterial blood pressure (r?=??0.58, p?Conclusions: Our results indicate that NT-proANP reflects more accurately direct thyroid hormone effects than NT-proBNP. Thyroid hormone-dependent hemodynamic effects seem to be overlapped on the direct stimulatory effect of thyroid hormones on NT-proANP secretion by cardiac myocytes.     

Puberty, pregnancy, gender and hormonal status--putative risk factors for diabetic nephropathy

Contemplation of non-genetic risk factors that are influencing the onset and development of diabetic nephropathy (diabetic kidney disease--DKD) is very important. This article is integrative, assessing the existent data about several possible risk factors for DKD. Because the age of onset and postpubertal duration of diabetes seems to be strongly correlated with DKD, it is feasible for puberty to be another independent risk factor. Data analysis regarding puberty and possible explanatory mechanisms to link it with DKD, as the connection with DKD of other situations, with special hormonal status (like pregnancy), is also part of this article. Summing up the data about hormonal status, we can conclude that ANF levels are a risk factor for diabetic nephropathy because they are implicated in diminution of urinary Na elimination and hypertension and subsequent urinary albumin excretion (UAE) in case of inadequate glycaemic control. The evidences regarding GH are indicating that it is a risk factor for DKD and that he is probably implicated in glomerular hypertrophy onset at puberty. The urinary elimination levels of GH are very strong correlated with UAE being putative early marker for DKD. Also the GH deficiency seems to be a protective mechanism for DKD apparition. GH is strongly correlated with IGF-1 that has very high urinary levels in microalbuminuric patients. These levels are very well related to UAE, kidney volume--important markers for glomerular hypertrophy. The evidences accumulated until now regarding the role of masculine gender, testosterone and estrogens in DKD are inarticulate.     

New tendencies in controlled drug release--liposomes entrapped in polymer matrices

Liposomes entrapment in different forms of polymers represents in the last few years a method to modify the drug release kinetics in order to attend the specificity of this phenomenon. This will result generally in complex systems in which liposomes are dispersed in polymer matrices like gels, hydrogels and microparticles. As a consequence the drug release will be influenced by both polymer matrix and small carrier entrapped in. The researchers are trying to control the release of drug from such solid complex system by modulating not only the vesicle properties but also those of polymer support. This kind of system is necessary also for the cases when time stable liposomes are desired, being already well known that the major drawback of this type of carrier is the stability in time and in different physiologic conditions.