131 I-induced changes in rat thyroid gland function.

Therapeutic doses of (131)I administered to thyrotoxic patients may cause thyroid failure. The present study used a rat model to determine thyroid function after the administration of different doses of (131)I (64-277 microCi). Thirty male Fisher rats in the experimental group and 30 in the control group (untreated) were followed for 6 months. The animals were 4 months old at the beginning of the experiment and were sacrificed at an age of 9 months. Hormone concentration was determined before (131)I administration (4-month-old animals) and three times following (131)I administration, when the animals were 7, 8, and 9 months old. The thyroid glands were removed and weighed, their volume was determined and histopathological examination was performed at the end of the experiment. Significant differences in serum triiodothyronine and thyroid-stimulating hormone concentration, measured at the age of 7, 8, and 9 months, were found in the experimental group. During aging of the animals, the concentration of thyroxin fell from 64.8 +/- 8.16 to 55.0 +/- 6.1 nM in the control group and from 69.4 +/- 6.9 to 25.4 +/- 3.2 nM in the experimental group. Thyroid gland volume and weight were significantly lower in the experimental than in the control group. Thyroid glands from the experimental group showed hyaline thickness of the blood vessel wall, necrotic follicles, a strong inflammatory reaction, and peeling of necrotic cells in the follicles. In conclusion, significant differences in hormone levels and histopathological findings indicated prolonged hypothyroidism after (131)I administration to rats, which was not (131)I dose dependent.

131I-induced changes in rat thyroid gland function

Therapeutic doses of 131I administered to thyrotoxic patients may cause thyroid failure. The present study used a rat model to determine thyroid function after the administration of different doses of 131I (64-277 µCi). Thirty male Fisher rats in the experimental group and 30 in the control group (untreated) were followed for 6 months. The animals were 4 months old at the beginning of the experiment and were sacrificed at an age of 9 months. Hormone concentration was determined before 131I administration (4-month-old animals) and three times following 131I administration, when the animals were 7, 8, and 9 months old. The thyroid glands were removed and weighed, their volume was determined and histopathological examination was performed at the end of the experiment. Significant differences in serum triiodothyronine and thyroid-stimulating hormone concentration, measured at the age of 7, 8, and 9 months, were found in the experimental group. During aging of the animals, the concentration of thyroxin fell from 64.8 ± 8.16 to 55.0 ± 6.1 nM in the control group and from 69.4 ± 6.9 to 25.4 ± 3.2 nM in the experimental group. Thyroid gland volume and weight were significantly lower in the experimental than in the control group. Thyroid glands from the experimental group showed hyaline thickness of the blood vessel wall, necrotic follicles, a strong inflammatory reaction, and peeling of necrotic cells in the follicles. In conclusion, significant differences in hormone levels and histopathological findings indicated prolonged hypothyroidism after 131I administration to rats, which was not 131I dose dependent.

Croatia has reached iodine sufficiency.

This study was performed in 2002, 6 yr after the introduction of a new regulation on salt iodination with 25 mg KI/kg of salt. The aim of the study was to evaluate whether further significant positive results of improved iodine intake could be observed among schoolchildren in Croatia. A total of 927 schoolchildren of both sexes, aged 6-12 yr, were included in the study. In Croatia, with a population of 4,437,460 the research was implemented in four major geographical regions: the Northwestern, Slavonia, Northern Adriatic and Dalmatian regions. Investigations included randomly selected pupils from regional centers and neighboring smaller towns or villages. The results have revealed that thyroid volumes were within the normal range according to the provisional WHO/ICCIDD reference values for sonographic thyroid volume in iodine-replete school-age children, updated in 2001. A significant improvement in medians of urinary iodine excretion was detected in 2002: from 9 microg/dl in 1991 to 14.6 microg/dl in Zagreb, from 4.3 microg/dl in 1995 to 13.1 microg/dl in Split, from 9.4 microg/dl in 1997 to 14.2 microg/dl in Rijeka and from 13.4 microg/dl in 1997 to 14.7 microg/dl in Osijek. An overall median of 14.0 microg/dl of urinary iodine excretion was detected in Croatian schoolchildren. The control of salt at different levels, from production to consumption, including salt produced in all three Croatian salt plants and imported salt, revealed that Croatian salt is adequately iodized. From severe iodine deficiency before the 1950s, through mild-to-moderate iodine deficiency in the 1990s, Croatia has now reached iodine sufficiency.

The role of direct radionuclide cystography in evaluation of vesicoureteral reflux.

The validity of voiding cystourethrography (VCUG) for detecting vesicoureteral reflux in children and assessing its extent was compared with that of direct radionuclide cystography (DRNC). Of 131 patients with recurrent urinary tract infection, all underwent DRNC and most also VCUG. Vesicoureteral reflux was found at DRNC in nine renal units (9 patients) in which VCUG was negative. In 17 renal units (15 patients) VCUG showed reflux to the ureter, but not to the renal pelvis, whereas DRNC revealed backflow from the bladder up to the renal pelvis. Reflux visualized at DRNC but not at VCUG was defined as grade Io. In all cases with reflux of grade I according to current classifications, DRNC showed reflux up to the renal pelvis. These observations make the distinction between grades I and II reflux in presently used classification less relevant and indicated the possible pathway of renal infection in patients with grade I vesicoureteral reflux and in so-called "elusive" reflux. We propose the addition of an extra grade (Io) of vesicoureteral reflux.

[Endemic goiter in Croatia]. / Endemska gusavost u Hrvatskoj.

In the early nineties, 40 years after the introduction of iodine prophylaxis in Croatia (10 mg KI/kg salt), a nationwide study was initiated with the aim to determine the real prevalence of goiter in the country. A total of 2436 schoolchildren of both sexes, aged 7-15 years, were included in the study. Investigations were designed in a way to cover most of geographical regions in Croatia and subjects were randomly selected. The prevalence of goiter in schoolchildren was assessed by palpation and in part by ultrasonography of the neck. At the same time urinary iodine excretion was measured and potassium iodide content in salt samples was determined. The results revealed the persistence of mild endemic goiter in the inland parts of Croatia with the prevalence of 6-29% in the age group 7-11 years and 10-43% among the age group 12-15 years. The overall goiter prevalence in schoolchildren in Croatia fluctuates from 8% to 35%. The urinary iodine excretion in Zagreb varied from 1.6 to 24.4 micrograms/dL with a median of 9.0, while in 14% it was below 5 micrograms/dL. The urinary iodine excretion in Samobor varied between 0.5 and 19 micrograms/dL with a median of 7.4 micrograms/dL, while in 30% it was below 5 micrograms/dL. Examination of salt from all three salt plants in Croatia showed iodine contents between 0.0 and 12.73 mg/kg with the average value of 5.39 mg/kg. Such prevalence, most probably due to less than optimum iodine intake, is unlikely to change until potassium iodide content of salt is increased from its present level of 10 mg of KI per kg of salt, with concomitant stricter observance of legal regulations.

Current status of endemic goiter in Croatia: the results of a nationwide study (1995).

In the beginning of the nineties, 40 years after introduction of iodine prophylaxis in Croatia, on a basis of a frequent reports coming from general practitioners about the presence of a rather high prevalence of goiter among schoolchildren, a nationwide study was initiated with the aim to determine the real prevalence of goiter in the country. A total of 2856 schoolchildren of both sexes, aged 7-15 years, were included into the study. Investigations were designed in a way to cover most of geographical regions in Croatia and subjects were randomly selected. The prevalence of goiter in schoolchildren was assessed by palpation and in part by ultrasonography of the neck. At the same time urinary iodine excretion was measured and iodine content in salt samples was determined. The results have revealed the persistence of mild endemic goiter in inland parts of Croatia with the prevalence of 6-29% in the age group 7-11 years and those of 10-43% among the age group 12-15 years. The overall goiter prevalence in schoolchildren in Croatia fluctuates from 8% to 35%. Such prevalence, most probably due to less than optimum iodine intake, is unlikely to change until iodine content of the salt is increased from its present level of 10 mg of Kl per kg of salt.