Postnatal isoform switch and protein localization of LEF1 and TCF7L2 transcription factors in cortical, thalamic, and mesencephalic regions of the adult mouse brain

β-Catenin signaling, leading to the activation of lymphoid enhancer-binding factor 1/T cell factor (LEF1/TCF) transcription factors, plays a well-established role in transcription regulation during development and tissue homeostasis. In the adult organism, the activity of this pathway has been found in stem cell niches and postmitotic thalamic neurons. Recently, studies show that mutations in components of β-catenin signaling networks have been associated with several psychiatric disorders, indicating the involvement of β-catenin and LEF1/TCF proteins in the proper functioning of the brain. Here, we report a comprehensive analysis of LEF1/TCF protein localization and the expression profile of their isoforms in cortical, thalamic, and midbrain regions in mice. We detected LEF1 and TCF7L2 proteins in neurons of the thalamus and dorsal midbrain, i.e., subcortical regions specialized in the integration of diverse sources of sensory information. These neurons also exhibited nuclear localization of β-catenin, suggesting the involvement of β-catenin/LEF1/TCF7L2 in the regulation of gene expression in these regions. Analysis of alternative splicing and promoter usage identified brain-specific TCF7L2 isoforms and revealed a developmentally coordinated transition in the composition of LEF1 and TCF7L2 isoforms. In the case of TCF7L2, the typical brain isoforms lack the so-called C clamp; in addition, the dominant-negative isoforms are predominant in the embryonic thalamus but disappear postnatally. The present study provides a necessary framework to understand the role of LEF1/TCF factors in thalamic and midbrain development until adulthood and predicts that the regulatory role of these proteins in the adult brain is significantly different from their role in the embryonic brain or other non-neural tissues.

Effectiveness of the iodine prophylaxis model adopted in Poland

OBJECTIVE

Most of the Polish territory has been classified as an iodine-deficient and endemic goiter area according to the International Council for Control of Iodine Deficiency (ICCIDD) criteria. In 1997 the obligatory model of iodine prophylaxis was implemented. Our investigations were aimed at the effectiveness of iodine prophylaxis in Poland.

METHODS

We assessed urinary iodine excretion and goiter prevalence in 5663 children aged 6-12 yr. The population of children from the same 27 schools was investigated from 1992 to 1994 (1406 girls and 1244 boys) and from 1999 to 2005 (1563 girls and 1450 boys) using identical laboratory and ultrasound methods.

RESULTS

We found significant increase in iodine urinary concentration (median 52 microg/l vs 93 microg/l, p<0.001) with accompanying drop in goiter prevalence (29.6% vs 5.2%, p<0.001) after implementation of iodine prophylaxis. Iodine excretion distribution changed significantly after 1997 with an increase in the percentage of children with iodine urinary concentration above 100 microg/l from 10.8% to 45.4%, respectively. A significantly higher iodine urinary concentration was observed in lowlands compared to uplands both before and after implementation of iodine prophylaxis (median, 50 microg/l vs 57 microg/l and 86 microg/l vs 114 microg/l, respectively, p<0.001). The goiter prevalence did not differ between girls and boys from 1992 to 1994 (28.8% vs 30.5%, p=0.35) and 1999 to 2005 (5.5% vs 4.9%, p=0.45).

CONCLUSIONS

Implementation of the new model of iodine prophylaxis in Poland in 1997 has led to significant increase in iodine urinary concentration and decrease in goiter prevalence among Polish schoolchildren. In the youngest group of children (6-8 yr olds), prevalence of goiter decreased to 3.2%--i.e. below endemic levels.

[The muscle system functioning in children in physiology and diabetes mellitus type I]

The muscular system of children and adolescents is characterized by a number of physiological distinct features, which result in weaker muscle strength and especially their sooner fatigue. All conditions that have negative effect on the metabolism of muscle fibres may easily lead to the intensification of that state of affairs. The muscle tissue is observed to have specific insulin action, which ensures proper muscle functioning. The imbalanced diabetes mellitus triggers off complex abnormalities of the cell metabolism, which may result in improper functioning of the muscular system. In good health, during muscle activity, some homeostatic mechanisms undergo certain disorders that bring about the development of fatigue. Diabetes mellitus intensifies the previously mentioned changes and may result in the increase of muscle fatigue. The above facts point out the necessity of further examinations of children suffering from diabetes mellitus type I, as physical effort is one of the elements of therapeutic treatment

[Hypothyroidism as the cause of lowered blood pressure during hemodialysis]

We present a case of a 19.5 years old, hemodialyzed, girl with frequent and dramatic episodes of hypotension. She presented slightly expressed symptoms of hypothyroidism, while the serum levels of hTSH, T3, T4 and fT4 were close to the bottom border of norm. The therapy with L-thyroxin (1.75 mg/kg b. w./24h) normalized the arterial blood-pressure and led to subside coexisting symptoms of hypothyroidism.

[Osteopenia and renal calcification in a 4.5 year old child with primary distal renal tubular acidosis treated for idiopathic renal hypercalciuria]

We present a case of a 4.5 years old boy suffering from hypercalciuria caused by a not diagnosed distal renal tubular acidosis. In the age of 2.5 years, after a banal infection the routine analysis showed a presence of numerous calcium phosphates in urine. Other diagnostic procedures showed: hypercalciuria, hyperphosphaturia, rather high calcemia and high values of UCa/cr and UPO4/cr ratios. HCO3 in serum 21.2 mmol/l, pH of urine 7.0. Kidneys and urinary tract-usg normal. These results induced the family doctor to make the diagnosis: idiopathic renal hypercalciuria. He advised the therapy with hydrochlorothiazide and limitations of calcium and vitamins D3 oral supply. This decision caused an illusory positive effect: decreased the UCa/cr ratio (to 0.96 mmol/mmol) without any reduction of calcemia. After a period of 12 months the UCa/cr ratio increased up to 1.31 and calcification of renal pyramids appeared. We diagnosed the distal renal tubular acidosis (some medical informations suggested the essential distal renal tubular acidosis) and osteopenia (DXA BMD L1-L4 below -1 s.d.). The therapy with NaHCO3 (about 2.6 mmol/kg) normalized the levels of HCO3a and calcium in serum, decreased the UCa/cr ratio to values 0.09-0.16 mmol/mmol.

A programme of iodine supplementation using only iodised household salt is efficient--the case of Poland

BACKGROUND

Iodine prophylaxis in Poland started in 1935 and has been interrupted twice: by World War II and in 1980 for economic reasons. Epidemiological surveys carried out after the Chernobyl accident in 1989 as well as in 1992/1993 and in 1994 as a 'ThyroMobil' study, revealed increased prevalence of goitre in children and adults. Ninety per cent of Poland was classified as an area of moderate iodine deficiency, and 10%, in the seaside area, as mild iodine deficiency territory. Iodine prophylaxis based on iodisation of household salt was introduced again in 1986 as a voluntary model and in 1997 as a mandatory model with 30+/-10 mg KI/kg salt.

OBJECTIVE

The evaluation of the obligatory model of iodine prophylaxis in schoolchildren from the same schools in 1994 and 1999.

METHODS

Thyroid volume was determined by ultrasonography. Ioduria in casual morning urine samples was measured using Sandell-Kolthoff's method, within the framework of the ThyroMobil study.

RESULTS

Goitre prevalence decreased from 38.4 to 7% and urinary iodine concentration increased from 60.4 to 96.2 microg/l mean values between 1994 and 1999. In four schools the prevalence of goitre diminished below 5%. In 1999, 70% of children excreted over 60 microg I/l, and 36% over 100 microg I/l, whereas in 1994 the values were 44 and 13% respectively.

CONCLUSION

The present findings indicate that iodine prophylaxis based only on iodised household salt is highly effective.

[Multifocal osteolysis as a result of delayed diagnosis for primary hyperparathyroidism]

Primary hyperparathyroidism caused by solitary adenomas occurs rarely (especially in children and adolescents). The clinical manifestations are usually subtle and that is why the mentioned disorder is usually late diagnosed and as an effect--late treated. We present the case of a 17 year old girl, an ambulatory patient who had been "observed" for over 12 months because of persistent ostealgia. She had not been properly diagnosed. The first diagnostic investigation of calcium and phosphate balance was provided only when multifocal osteolysis of tibias, hip and metacarpal bones was detected and biopsy of the mentioned osteolytic lesions was done. After the admission to The Department of Pediatrics, Endocrinology and Disease of Adolescents: Ca 3.02-3.06 mmol/l, PO4- 0.32-0.62 mmol/l, ACP 19.4 U/l, ALP 864 U/l, PTH 770 pg/ml [normal values: 10-70]. Densitometry findings: BMD (Neck[L]) 0.636 g/cm2, BMD (Neck[R]) 0.722 g/cm2. The parathyroid adenoma was removed after the exploration and localization with MIBI99mTc (scintigraphy). Clinical diagnosis was verified by histologic findings. 5 months after: BMD (Neck[L]) 0.850 g/cm2, BMD (Neck[R]) 0.741 g/cm2, calcemia 2.38 mmol/l, phosphatemia 1.14 mmol/l, ACP 6.2 U/l, ALP 159 U/l. Radiograms show evident improvement of bone tissue structure.

[Prolactinoma as a cause of primary amenorrhea in a 16-year-old girl]

16 years old girl with prolactinoma and amenorrhoea primaria was treated with Bromocorn. The symptoms of hyperprolactinemia regressed gradually--Graaf follicules started to mature in ovaries, the menstruation bleeding appeared after 12 months. The reduction of tumor mass has been obtained during this time.

Serum cholinesterase activity in children with gastroduodenitis or peptic ulcer disease

Serum cholinesterase /ChE/ investigation in children with gastroduodenitis or peptic ulcer disease indicate its low activity, specially in children with peptic ulcer disease. These investigation can be index of parasympathetic tonus in digestive tract disease.

[Bioelectric activity of the brain in insulin-induced hypoglycemia in children with growth deficiency]

The somatotropin levels during insulin-induced hypoglycemia was assessed in 30 children with growth deficiency. The variation of glycemia and somatotropin activity were evaluated during 120-minutes recording of the bioelectric activity of the brain. In 90% of children generalized and paroxysmal abnormalities were found during insulin-induced hypoglycemia. The exacerbation of them was correlated with the maximal decrease of the glucose level. Early appearance of the abnormal EEG findings after the administration of insulin and the significant intensity of them was more common in younger children with marked growth deficiency and low somatotropin activity.

[Excretion of catecholamines in juvenile diabetes mellitus]

Twenty four hours' urinary excretion of catecholamines was examined in 30 children suffering from diabetes and in 30 healthy children. The results showed that in children suffering from diabetes, excretion of adrenaline was increased and that of noradrenaline decreased when compared with healthy children. Taking into consideration changes in the sympatho-adrenergic system activity in cases with different degrees of compensation of metabolic processes during insulinization, it should be stressed that in children with ketoacidosis, excretion of catecholamines was still different in comparison with control group. On the other hand in children with compensate diabetes after insulin therapy, that differences were little. Marked increase in free adrenaline excretion observed in children with ketoacidosis and its normalization by effective insulinization seems to support the diabetogenic and ketogenic role of this neurohormone. Decrease in free noradrenaline excretion in children suffering from juvenile diabetes appears to suggest that there is a diminished sensitivity of the sympathetic system resulting probably from specific autonomic neuropathy accompanying this disease.