Hungarian experience with Langerhans cell histiocytosis in childhood.

The Langerhans cell histiocytosis (LCH) in children is relatively rare and the long-term analysis of therapy results has not been done yet in Hungary. The aim of this study was to investigate the incidence, clinical features, prognostic risk factors, and treatment results of children's LCH in Hungary in a 20-year period. Children less than 18 years of age with newly diagnosed LCH in Hungary were entered in this study. Clinical data of all children with LCH were reported to the National Childhood Cancer Registry in Hungary from 1981 to 2000. The clinical files were collected and abstracted for information regarding age at diagnosis, gender, disease characteristics, treatment, and outcome of treatment. Median follow-up duration of surviving patients is 10.98 years. Between January 1981 and December 2000, 111 children under 18 years of age were newly diagnosed with LCH in Hungary. The annual incidence of LCH in children younger than 18 years of age was 2.24/million children. The male-female ratio was 1.36:1; the mean age was 4 years 11 months. Thirty-eight children had localized disease and in 73 cases systemic dissemination was found already at the time of diagnosis. Twenty-two patients were treated only by local surgery, 7 by surgery with local irradiation, and 5 children got only local irradiation. In 2 cases remission was achieved with local steroid administration. Seventy-five patients received chemotherapy. In the 20 years of the study 14 children died, 9 due to the progression of the disease. Sixteen patients had relapse with a mean of 2.16 +/- 1.29 years after the first diagnosis. Three patients with relapse got chemotherapy generally used in lymphoma and remission was achieved. The overall survival of all patients (n = 111) was 88.3 +/- 3.1% at 5 years and 87.3 +/- 3.2% at 10 and 20 years. Childhood LCH is a well-treatable disease and the survival rate is high. Even disseminated diseases have a quite good prognosis in childhood.

Temporary pure red-cell aplasia during valproate monotherapy: clinical observations and spectral electroencephalographic aspects.

We report the case of a 4-year-old boy with pure red-cell aplasia associated with sodium valproate monotherapy. Treatment with valproate was initiated because of idiopathic tonic-clonic seizures; he became free of seizures. During the introduction of and ongoing antiepileptic drug treatment, clinical and laboratory controls using electroencephalographic (EEG) spectral analysis were performed at regular intervals and disclosed normal values. Ten months after the introduction of valproate, clinical examination was normal except for marked pallor. Peripheral blood showed macrocytic anemia and the bone marrow finding was isolated absolute erythroblastopenia. At the same time, significant changes in EEG background activity were present as well-defined slowing. There was an increase in the relative power of theta activity and a decrease in alpha 2 activity in the occipital regions. Valproate was discontinued and phenobarbital therapy introduced. A complete resolution of the hematologic damage was observed after valproate withdrawal. Recovery of the hematologic parameters started 14 days after discontinuation of valproate therapy, while normalization of EEG background activity was observed earlier. The patient maintained stable hematologic values and seizure control without disturbances of the spectral EEG. After 6 months of phenobarbital therapy, re-administration of sodium valproate was not followed by recurrence of any clinical or electrophysiologic symptoms or abnormalities.

Subcellular distribution of normal and mutant vitamin D receptors in living cells. Studies with a novel fluorescent ligand.

To understand the subcellular localization of the vitamin D receptor (VDR) and to measure VDR content in single cells, we recently developed a fluorescent labeled ligand, 4,4-difluoro-4-bora-3a, 4a-diaza-s-indacene (BODIPY)-calcitriol. This tagged hormone has intact biological activity, high affinity and specific binding to the receptor, and enhanced fluorescent emission upon receptor binding. Using BODIPY-calcitriol, here we monitored the subcellular distribution of VDR in living cultured cells by microscopy. Time course studies showed that an equilibrium between the cytoplasmic and nuclear hormone binding developed within 5 min and was maintained thereafter. We found a substantial proportion of VDR residing in the cytoplasm, colocalized with endoplasmic reticulum, the Golgi complex, and microtubules. Confocal microscopy clarified the presence of VDR within discrete regions of the nucleus and along the nuclear envelope. There was no VDR in the plasma membrane. Low affinity BODIPY-calcitriol binding sites were in the mitochondria. Mutations in the VDR gene selectively and specifically altered BODIPY-calcitriol distribution. Defects in the hormone binding region of VDR prevented both nuclear and cytoplasmic hormone binding. Defects in the DNA binding region decreased the nuclear retention of VDR and prevented localization to nuclear foci. These results with BODIPY-calcitriol reveal cytoplasmic VDR localization in living cells and open the possibility of studying the three-dimensional architecture of intranuclear target sites.

Visualization of glucocorticoid receptor translocation and intranuclear organization in living cells with a green fluorescent protein chimera.

A highly fluorescent mutant form of the green fluorescent protein (GFP) has been fused to the rat glucocorticoid receptor (GR). When GFP-GR is expressed in living mouse cells, it is competent for normal transactivation of the GR-responsive mouse mammary tumor virus promoter. The unliganded GFP-GR resides in the cytoplasm and translocates to the nucleus in a hormone-dependent manner with ligand specificity similar to that of the native GR receptor. Due to the resistance of the mutant GFP to photobleaching, the translocation process can be studied by time-lapse video microscopy. Confocal laser scanning microscopy showed nuclear accumulation in a discrete series of foci, excluding nucleoli. Complete receptor translocation is induced with RU486 (a ligand with little agonist activity), although concentration into nuclear foci is not observed. This reproducible pattern of transactivation-competent GR reveals a previously undescribed intranuclear architecture of GR target sites.

Development of a biologically active fluorescent-labeled calcitriol and its use to study hormone binding to the vitamin D receptor.

To gain better insight into the mechanism of steroid receptor activation and calcitriol action, we have developed the first pharmacologically relevant fluorescent-labeled ligand for the vitamin D receptor (VDR). Purity and structure of three BODIPY-labeled calcitriol derivatives were characterized by TLC, HPLC, and 1H-NMR spectroscopy. 3 beta-BODIPY-calcitriol was the most potent derivative to induce 25-hydroxyvitamin D3 24-hydroxylase activity and to inhibit cell proliferation. It was taken up rapidly and specifically and was not cleaved by endogenous esterases. 3 beta-BODIPY-calcitriol also retained high-affinity binding to the VDR. Hormone binding to the receptor was measured by spectrofluorometry in high-salt extracts from cultured cells with wild-type VDR, from cells virally over-expressing the human VDR, and in intact cells with and without VDR. Results from fluorescent binding studies agreed with results from radioligand assays. The most useful feature of this reagent is that its fluorescence emission increases severalfold upon binding to VDR. This allows direct monitoring by microscopy of ligand receptor interactions in living cells. Fluorescent-labeled calcitriol can be a valuable diagnostic tool for cancer research and is essential for exploring the subcellular localization of VDRs.

Ki-1 positive (anaplastic, large cell) lymphoma (case reports and review).

Ki-1 positive (anaplastic, large cell) lymphoma is a subgroup of non-Hodgkin lymphomas identified recently by Ki-1 (or BER-H2) (CD 30) monoclonal antibody. The clinicopathological features of two such pediatric cases of lymph node origin described here, and also the available literature emphasize the heterogenous nature of Ki-1 positive lymphomas, in almost every respect. Nevertheless, the Ki-1 antibody serves as an important diagnostic tool to differentiate lymphomas from other anaplastic, large malignancies.

[Pelvic masses in childhood: ultrasonographic imaging]. / Kismedencei terimék gyermekkorban: az ultrahangkép sajátosságai.

The echographic appearance of pelvic masses in children was examined in 38 patients. Sonography was correct in determining the site of origin in all cases. Cystic uterine masses and cystic ovarian masses were the most specific, representing hydrometrocolpos and benign ovarian cysts. A nonspecific sonographic pattern was encountered with complex masses, which proved to be ovarian teratomas, hemorrhagic ovarian cysts and pelvic abscesses. Although a number of characteristic features of teratomes have been described, these signs were seen very rarely in children.