Morphological and functional changes in neonatally X-irradiated thyroid gland in rats.

Exposure to ionized radiation in childhood has been recognized as a risk factor for the development of thyroid cancer and possibly for other thyroid disorders. However, the effects of neonatal radiation exposure on thyroid morphology and functions have never been explored despite its potential importance. One-week-old male Wistar rats were subjected to cervical X-irradiation at 6 and 12 Gy. Animals were examined at the ages of 2, 8 and 18 weeks old. For comparison, 8-week-old rats were cervically X-irradiated at the same doses. Thyroid histology was examined by computer-assisted microscopy to measure areas of colloid and epithelium of thyroid follicles as well as epithelial heights. In rats that received cervical X-irradiation at 1 week old, the colloid size of thyroid follicles decreased at the age of 8 weeks old in a radiation-dose dependent manner. This morphological change was persistently found at 18 weeks old. There were no significant differences in serum total T3 or T4 levels among the groups. Serum TSH levels increased significantly in 8-week-old rats neonatally X-irradiated. Thyroglobulin (Tg) mRNA and protein expressions were significantly decreased in the neonatally-irradiated group while thyroid peroxidase mRNA express increased at 18 weeks old. None of these changes were observed in the rats X-irradiated at 8 weeks old. In conclusion, our results clearly demonstrated that neonatal rat thyroid was sensitive to ionized radiation, developing specific morphological changes characterized by smaller thyroid follicles along with changes in serum TSH levels and Tg expressions in the thyroid tissue.

Decomposition of Iodinated Pharmaceuticals by UV-254 nm-assisted Advanced Oxidation Processes.

Iodinated pharmaceuticals, thyroxine (a thyroid hormone) and diatrizoate (an iodinated X-ray contrast medium), are among the most prescribed active pharmaceutical ingredients. Both of them have been reported to potentially disrupt thyroid homeostasis even at very low concentrations. In this study, UV-254 nm-based photolysis and photochemical processes, i.e., UV only, UV/H2O2, and UV/S2O82-, were evaluated for the destruction of these two pharmaceuticals. Approximately 40% of 0.5µM thyroxine or diatrizoate was degraded through direct photolysis at UV fluence of 160mJcm-2, probably resulting from the photosensitive cleavage of C-I bonds. While the addition of H2O2 only accelerated the degradation efficiency to a low degree, the destruction rates of both chemicals were significantly enhanced in the UV/S2O82- system, suggesting the potential vulnerability of the iodinated chemicals toward UV/S2O82- treatment. Such efficient destruction also occurred in the presence of radical scavengers when biologically treated wastewater samples were used as reaction matrices. The effects of initial oxidant concentrations, solution pH, as well as the presence of natural organic matter (humic acid or fulvic acid) and alkalinity were also investigated in this study. These results provide insights for the removal of iodinated pharmaceuticals in water and/or wastewater using UV-based photochemical processes.

Effect of three different protocols of low-level laser therapy on thyroid hormone production after dental implant placement in an experimental rabbit model.

OBJECTIVE: The purpose of this study was to assess the systemic effects of low-level laser therapy (LLLT) on thyroid gland function and, consequently, calcium regulation - as measured by serum triiodothyronine (T3), thyroxine (T4), and free calcium levels - when administered after dental implant placement in a rabbit model. BACKGROUND DATA: Protocols for the use of laser therapy in several clinical procedures are currently under investigation, as not all of the actions and systemic effects of laser irradiation have been clearly established. MATERIALS AND METHODS: Forty male adult New Zealand rabbits were distributed across five groups of eight animals each: two control groups (C-I and C-II) of unirradiated animals, and three experimental groups (E-5, E-10, and E-20), each exposed to a distinct dose of gallium-aluminum-arsenide (GaAlAs) laser [λ=830 nm, 50 mW, continuous wave (CW)] every 48 h for a total of seven sessions. The total dose per session was 5 J/cm(2) in E-5, 10 J/cm(2) in E-10, and 20 J/cm(2) in E-20. Animals in C-II and all experimental groups underwent surgical extraction of the mandibular left incisor followed by immediate placement of an osseointegrated implant (Nanotite(®), Biomet 3i(™)) into the socket. Animals in group C-I served as an absolute control for T3, T4, and calcium measurements. The level of significance was set at 5% (p≤0.05). RESULTS: ANOVA with Tukey's post-hoc test revealed significant differences in T3 and calcium levels among experimental groups, as well as significant within-group differences in T3, T4, and calcium levels over time. CONCLUSIONS: Although not reaching abnormal values, LLLT applied to the mandible influenced thyroid function in this model.

Assessment of the systemic effects of low-level laser therapy (LLLT) on thyroid hormone function in a rabbit model.

The aim of this study was to assess the effects of low-level laser therapy (LLLT) applied to a dental extraction socket on thyroid gland function in a rabbit model, based on serum triiodothyronine and thyroxine levels. Sixteen male New Zealand rabbits were randomly distributed into two groups: a control group (non-irradiated animals) and an experimental group (irradiated animals: one irradiation point in the extraction socket of the lower incisor). Animals in the experimental group were irradiated with an aluminium gallium arsenide diode laser (AlGaAs; wavelength 830 nm, 40 mW, CW laser), for 13 days, every 48 h, at a dose of 6 J/cm(2) per session, resulting in a total dose of 42 J/cm(2). Serum triiodothyronine and thyroxine levels were measured in both groups before extraction and on the last day of observation (day 15). There were no statistically significant differences between the groups in pre- and post-irradiation triiodothyronine and thyroxine values. With the irradiation protocol used in this study, LLLT did not affect thyroid function in rabbits as assessed by circulating serum triiodothyronine and thyroxine levels.

Effects of the electromagnetic field, 60 Hz, 3 microT, on the hormonal and metabolic regulation of undernourished pregnant rats.

Epidemiological studies have implicated maternal protein-calorie deficiency as an important public health problem in developing countries. Over the last decades, a remarkable diffusion of electricity and an increased level of the electromagnetic field (EMF) in the environment have characterized modern societies. Therefore, researchers are concerned with the biological effects of 50-60 Hz, EMF. The aim of this paper is to show the effects of EMF of 60 Hz, 3 muT, exposure for two hours per day in the regulation of the hormonal and metabolic concentrations in pregnant rats, which were fed by Regional Basic Diet (RBD) during their pregnancy as compared with pregnant rats fed a standard diet. Pregnant rats exposed to EMF of 60 Hz, 3 muT, over the pregnancy and fed with RBD presented an increase in glucose release when compared with the Group subjected only to the RBD ration. Rats fed RBD presented a decrease in their insulin and cortisol serum levels when compared with the Group fed with casein. The T3 and T4 concentrations presented the greatest variation among the Groups. The relation T4:T3 was much exaggerated in the Group subjected to RDB and exposed to EMF when compared to the others. In conclusion, the group subjected to the association of EMF and undernutrition suffered a decrease in its serum concentration of T4 and T3 when compared to the well-nourished group and the relationship T4:T3 in the former group was almost eighteen-fold the later one.

Effects of the Electromagnetic field, 60 Hz, 3 µT, on the hormonal and metabolic regulation of undernourished pregnant rats / Efeitos do campo eletromagnético, 60 Hz, 3µT, na regulação hormonal e metabólica de ratas prenhes desnutridas

Epidemiological studies have implicated maternal protein-calorie deficiency as an important public health problem in developing countries. Over the last decades, a remarkable diffusion of electricity and an increased level of the electromagnetic field (EMF) in the environment have characterized modern societies. Therefore, researchers are concerned with the biological effects of 50-60 Hz, EMF. The aim of this paper is to show the effects of EMF of 60 Hz, 3 μT, exposure for two hours per day in the regulation of the hormonal and metabolic concentrations in pregnant rats, which were fed by Regional Basic Diet (RBD) during their pregnancy as compared with pregnant rats fed a standard diet. Pregnant rats exposed to EMF of 60 Hz, 3 μT, over the pregnancy and fed with RBD presented an increase in glucose release when compared with the Group subjected only to the RBD ration. Rats fed RBD presented a decrease in their insulin and cortisol serum levels when compared with the Group fed with casein. The T3 and T4 concentrations presented the greatest variation among the Groups. The relation T4:T3 was much exaggerated in the Group subjected to RDB and exposed to EMF when compared to the others. In conclusion, the group subjected to the association of EMF and undernutrition suffered a decrease in its serum concentration of T4 and T3 when compared to the well-nourished group and the relationship T4:T3 in the former group was almost eighteen-fold the later one.

Estudos epidemiológicos têm mostrado que a deficiência proteico-calórica é um importante problema nos países em desenvolvimento. Durante as últimas décadas, a sociedade moderna tem sido caracterizada pelo aumento no número de equipamentos elétricos e como consequência um aumento no nível do campo eletromagnético (CEM) no ambiente. No entanto, os pesquisadores estão preocupados com os efeitos biológicos dos CEM de 50-60 Hz. O objetivo deste artigo é mostrar os efeitos do CEM de 60 Hz, 3 μT, nas concentrações hormonais e metabólicas de ratas prenhes, expostas duas horas por dia ao CEM, alimentadas pela Dieta Básica Regional (DBR) comparando com ratas submetidas às mesmas condições, mas alimentas com dieta padrão. Ratas prenhes expostas ao CEM de 60 Hz, 3 μT, durante a prenhez e alimentadas com a DBR apresentaram um aumento na liberação de glicose quando comparadas com o grupo alimentado pela DBR sem CEM. As ratas alimentadas pela DBR apresentaram uma diminuição nos níveis de insulina e cortisol quando comparadas com o grupo alimentado pela caseína. As concentrações de T3 e T4 apresentaram a maior variação entre os grupos. A relação T4:T3 foi muito exagerada no grupo alimentado pela DBR e exposto ao CEM quando comparado com os outros. Conclusão, os animais que foram submetidos à desnutrição e ao CEM sofreram uma diminuição na concentração sérica de T4 e T3 quando comparados com os animais bem nutridos e a relação T4:T3 no primeiro grupo foi quase 18 vezes a relação de T4:T3 no grupo bem nutrido.

Effects of 900 MHz electromagnetic field on TSH and thyroid hormones in rats.

In this study, the effects of exposure to a 900 megahertz (MHz) electromagnetic field (EMF) on serum thyroid stimulating hormone (TSH) and triiodothronine-thyroxin (T3-T4) hormones levels of adult male Sprague-Dawley rats were studied. Thirty rats were used in three independent groups, 10 of which were control (without stress and EMF), 10 of which were exposed to 900 MHz EMF and 10 of which were sham-exposed. The exposures were performed 30 min/day, for 5 days/week for 4 weeks to 900 MHz EMF. Sham-exposed animals were kept under the same environmental conditions as the study groups except with no EMF exposure. The concentration of TSH and T3-T4 hormones in the rat serum was measured by using an immunoradiometric assay (IRMA) method for TSH and a radio-immunoassay (RIA) method for T3 and T4 hormones. TSH values and T3-T4 at the 900 MHz EMF group were significantly lower than the sham-exposed group (p<0.01). There were no statistically significant differences in serum TSH values and T3-T4 hormone concentrations between the control and the sham-exposed group (p>0.05). These results indicate that 900 MHz EMF emitted by cellular telephones decrease serum TSH and T3-T4 levels.

Direct labeling of chemotactic peptide ForNleLFNleYK with radioiodine in vivo stability evaluation

Some peptides are naturally occuring inflammatory mediators which specifically bind to receptors abundantly present in the area of inflammation, and owing to their small size, they rapidly clear from all non-target tissues. ForNleLFNleYK is a synthetic chemotactic peptide with high affinity to receptors on the white blood cell membranes. This hexapeptide contains a tyrosine residue susceptible to iodination by oxidative eletrophilic substitution - direct labeling. The aim of this study was the radioiodination of ForNleLFNleYK using the direct method (chloramine T) and its in vivo stability evaluation. The labeled compound was obtained in a short reaction time with high radiochemical purity (96.8 ± 0.84 por ciento) and remained stable over 48 hours when stored at low temperature. Biological distribution studies showed an uptake in inflammated tight significantly greater than the normal tight (p < 0.05, Student t test), and some in vivo dehalogenation of the compound.

[The functional status of the thyroid system in those irradiated as a consequence of the accident at the Chernobyl Atomic Electric Power Station (based on screening study data)]. / Funktsional'nyi stan tyreoïdnoï systemy u oprominenykh vnaslidok avariï na ChAES (za danymy skryninhovoho doslidzhennia).

A screening study was made of functional indices for the status of the thyroid system in 1097 persons who took part in the elimination of the effects of the Chernobyl accident (PChAEE) during the "iodine" and "non-iodine" periods of irradiation. In 94.6% of the "iodine" period PChAEE, the basal levels of the thyroid-stimulating hormone (TSH) were in the normal range, 4.79% displayed a rise in the parameter. 90.06% of the "non-iodine" period had normal range TSH, 8.77% exhibited augmented levels. 94.68% of the "iodine" period PChAEE showed normal range for the basal levels of free thyroxin, in 3.72% there was a rise, in 1.6% a decrease in the values. Among the examinees of the "non-iodine" period, the levels of free thyroxin were within normal range in 92%, above norm in 5%, decreased in 3%. The level of antibodies to thyroglobulin in 86.38% of the "iodine" period examinees was in the normal range, in 90.99% of the "non-iodine" period it was also normal. There were no statistically significant differences suggesting effects of radiation factors of the "iodine" period of irradiation on the functional indices for the hypophysis-thyroid system during the first 7 years following irradiation.

[Concentration of T3 and T4 in blood of non-irradiated and irradiated with different doses rats fasted for two days beforehand]. / Kontsentratsiia T3 i T4 v krovi u neobluchennykh i obluchennykh v raznykh dozakh krys, golodavshikh v techenii 2 sutok pered zaboem.

There were no changes in concentration of T3 and T4 in blood of the rats that were irradiated with a dose of 0.5, 1, 2, 4 and 6 Gy in comparison with non-irradiated rats, if the animals were not fed for two days before decapitation. This suggests that the effect of ionizing radiation on thyroid function is mediated by anorexia syndrome. The decrease in concentration of T4 after exposure to 8 Gy cannot be explained by postradiative anorexia and most likely is connected with starting enterotoxemy in difficult cases of acute radiation sickness.

[Seasonal changes in the triiodothyronine level of the blood evoked by ultraviolet irradiation in vitro]. / Sezonnye izmeneniia urovnia triiodtironina v krovi, vyzvannye ul'trafioletovym oblucheniem in vitro.

Ultraviolet irradiation (lambda = 254 nm) of the whole blood of juvenile bulls in vitro results in a plasmatic T3 increase dependent on the time of exposure. Dynamics of the growth of hormone content because of UV varies with season. No negative correlation between plasmatic T3 and T4 in irradiated and non-irradiated blood samples was stated. Hence, increased T3 levels in blood after UV irradiation in vitro is a consequence of the output of erythrocyte-deposited hormone rather than photoactivation of the T4 to T3 conversion.

[The structural-functional status of the thyroid in patients with nodular goiter evacuated from the 30-kilometer zone of the Chernobyl Atomic Electric Power Station]. / Strukturno-funktsional'nyi stan shchytovydnoï zalozy khvorykh na vuzlovyi zob, evakuiovanykh iz 30-kilometrovoï zony ChAES.

An analysis was performed of results of ultrasonic and hormonal investigations in 239 patients with nodular goiter revealed in a screening-type clinical and laboratory examination of the 3371 persons evacuated from the 30-km zone of ChNPP, at their ages randing between 18 to 68 years. In 84.20% of patients in the group who took part in the elimination of effects of the Chernobyl accident (PEEA)--"PEEA + the evacuated"--the diameter of the nodules did not exceed 1 cm, in 6.1% it ranged from 1 to 2 cm, and in 13.41% it exceeded 2 cm. Distribution of nodules in the group "the evacuated" did not differ much from that in the above group. In 20% of patients with nodular goiter, there were functional disturbances concurrent with the autoimmune processes. No effects were detected of small doses of extra irradiation on the pattern of structural-and-functional indices in patients with nodular goiter evacuated from the 30-km zone of ChNPP who took part in EEA.

[Distribution of ionizing radiation absorption in microstructures of a biosystem]. / Raspredelenie pogloshcheniia énergii ioniziruiushchego izlucheniia po mikrostrukturam biosistem.

The method of determination of the gamma-radiation absorption distribution in microstructures of a biosystem is proposed. The absorption capacity and energy absorption distribution of some biomolecules, mass coefficients and optical density of blood and thyroid gland are calculated. Influence of the pollution of biosystem microstructures (liver, blood, thyroid, gland) by hard elements on the energy absorption distribution is demonstrated.

[Modification of Ca2+ metabolism in the blood cells of cattle with radiation-induced thyroid disorder after the Chernobyl nuclear power plant accident]. / Modifikatsiia obmena Ca2+ v kletkakh krovi korov s radiatsionnym povrezhdeniem shchitovidnoi zhelezy posle avarii na Chernobylskoi AES.

Increasing of Ca2+ concentration in cytoplasm and of the rate of 45Ca iflux into cows erythrocytes in 19-24 month after Chernobyl accident was revealed. Correlation between Ca2+ concentration in cytoplasm of erythrocytes and thyroxin content in plasma of cows with radioiodine damage of thyroid gland was found. Reduction of the rate of 45Ga influx into erythrocytes in cows with radiation doses of 20-60 By on thyroid gland was shown in later time after accident (3-5 years). Changes in Ca2+ permeability through membranes of erythrocytes and neutrophils after injection of 131I into calves in doses of 300 Gy and more on thyroid gland was found.

Effect of excipients on the stability of levothyroxine sodium tablets.

Levothyroxine sodium tablets from two different manufacturers were analysed using the USP-NF method of analysis, a stability-indicating high pressure liquid chromatographic (HPLC) procedure. The results indicate that one particular manufacturer's 0.2-mg pink tablets contain some excipient(s) which act as a catalyst to hasten decomposition after extraction of levothyroxine for analysis. The same tablets from a different batch showed an additional long peak in the chromatogram, which indicated that the excipient(s) may have been changed. The same manufacturer has also used three different types of bottles/lids for the same product during the last year. Good manufacturing practice requires that new compatibilities/stability studies be conducted to assure the quality of the product. Ongoing stability studies are required by the Food and Drugs Administration (FDA). The use-life of 0.2-mg pink tablets of this manufacturer may be short.