OXIDATIVE STRESS IN HUMAN THYROID GLAND UNDER IODINE DEFICIENCY NODULAR GOITER: FROM HARMLESSNESS TO HAZARD DEPENDING ON COPPER AND IODINE SUBCELLULAR DISTRIBUTION

Background. Thyroid disorders are the second most common endocrinopathies found in humans and animals. Determination of their key molecular markers presents a special interest.Objective. We studied iodine and copper accumulation in nodular, paranodular and contralateral (not affected tissue by node) tissues of human thyroid gland in relation to the level of metal-binding proteins, potential antioxidants, and oxidative changes in tissue for this goal. Lower level of organificated iodine and higher level and mass fraction of inorganic iodine and copper in the nodular and paranodular tissue versus contralateral part of thyroid gland was established.Results. The level of both metal-binding and apo-form of metallothioneins was higher. Content of reduced glutathione was lower in node-affected tissue compared to the contralateral part. Signs of oxidative stress (higher activity of superoxide dismutase, catalase, glutathione-transferase and level of oxyradicals) and cytotoxicity (higher cathepsin D activity, higher level of DNA strand breaks and glycolysis activation) in affected tissue were observed. The range of indice variability in paranodular tissue was smaller than in nodule compared to the parenchyma of contralateral part.Conclusions. Excess of copper unbound to metallothionein in goitrous-changed tissue and high level of inorganic iodine could be the reason for elevated DNA fragmentation and increased lysosomal membrane permeability and activation of antioxidant defense. The main criterions of goiter formation were represented by low level of organificated iodine and high level of DNA damage in thyroid gland.KEY WORDS: iodine deficiency nodular colloidal goiter, iodine, copper, metallothioneins, oxidative stress, cytotoxicit

Trace elements storage peculiarities and metallothionein content in human thyroid gland under iodine deficiency euthyroid nodular goiter

Accumulation of iodine and copper in the node, paranodular and contralateral (not affected tissue by node) tissues of thyroid gland in relation to the level of metal-binding proteins, potential antioxidants and oxidative changes in tissue was investigated. To assess the severity of the pathological process the molecular markers of cytotoxicity were used. The reduction of total iodine (by 19.5%), increase of inorganic iodine fraction (by 82.4%) and total copper content (twice) in paranodular and nodular tissues compared with contrlateral part have been established. Excess of copper in goitrous-changes tissue was partially accumulated in the metallothioneins. The level of metal-binding form of metallothioneins and reserve of free thiols of these proteins was higher two-three times and lower content of reduced glutathione in node-affected tissue compared to the contralateral part. Signs of cytotoxicity among them: higher cathepsine D free activity (up to 84.6% and 134.4% in paranodular tissue and node respectively) and higher level of DNA strand breaks in the node (up to 22.6%) were observed. In paranodular tissue the range of indices variability compared with parenchyma of contralateral part is shorter than in the node. Thus, under low level of iodine organification and high copper level in goitrous-modified tissue of thyroid gland metallothionein may provide a partial compensatory effect on prooxidative processes

Dual SLO/T-scan based en face ultrahigh resolution OCT for ophthalmic imaging

We report a versatile imaging system combining scanning laser ophthalmoscopy (SLO) and T-scan based en face ultrahigh resolution optical coherence tomography (OCT). The image carrier is generated using the optical path difference modulation introduced by the X-Y galvo-scanner mirrors specific to en face OCT (without optical modulators in the reference arm). The light source is a compact superluminescent diode based source with 150 nm FWHM spectrum, centered at 890 nm. We demonstrate en face B-scan and C-scan ultrahigh resolution OCT imaging of the human retina in vivo, with an axial resolution of 3.2 μm in tissue. The system is capable of acquiring large lateral size ultrahigh resolution OCT scans of a maximum field size of 20°. The acquisition speed is up to 2 frames/s for both OCT B-scans and C-scans. The measured system sensitivity is more than 98 dB, for a power level to the target of 1 mW and maximum lateral scan size. The C-scans are, to the best of our knowledge, the first and the largest size reported ultrahigh resolution C-scans of the human retina in vivo. The instrument is assembled on a chin rest and ready to be used for clinical imaging. SLO and ultrahigh resolution OCT C-scans are acquired simultaneously and displayed side by side. This allows users in a clinical environment to correlate details of the same feature in the area of interest in both images and also choose precisely in the SLO image the location where to perform the ultrahigh resolution en face B-scan

Dual Amplification 850 nm FDML Laser

Fourier domain mode locked (FDML) lasers have been widely used in optical coherence tomography (OCT) for many years at 1550 nm, 1310 nm and 1064 nm [1]–[4]. Developing a shorter wavelength FDML laser is interesting for eye imaging for instance, due to less water absorption and increased scattering which can improve the contrast of low scattering features