SHOX mutations in idiopathic short stature and Leri-Weill dyschondrosteosis: frequency and phenotypic variability

OBJECTIVE: The frequency of SHOX mutations in children with idiopathic short stature (ISS) has been found to be variable. We analysed the SHOX gene in children with ISS and Leri-Weill dyschondrosteosis (LWD) and evaluated the phenotypic variability in patients harbouring SHOX mutations. PATIENTS: Sixty-three ISS, nine LWD children and 21 affected relatives. METHODS: SHOX gene deletion was evaluated by fluorescence in situ hybridization (FISH), Southern blotting and segregation study of polymorphic marker. Point mutations were assessed by direct DNA sequencing. RESULTS: None of the ISS patients presented SHOX deletions, but two (3.2%) presented heterozygous point mutations, including the novel R147H mutation. However, when ISS patients were selected by sitting height : height ratio (SH/H) for age > 2 SD, mutation frequency detection increased to 22%. Eight (89%) LWD patients had SHOX deletions, but none had point mutations. Analysis of the other relatives in the families carrying SHOX mutations identified 14 children and 17 adult patients. A broad phenotypic variability was observed in all families regarding short stature severity and Madelung deformities. However, the presence of disproportional height, assessed by SH/H, was observed in all children and 82% of adult patients, being the most common feature in our patients with SHOX mutations. CONCLUSION: Patients with SHOX mutations present a broad phenotypic variability. SHOX mutations are very frequent in LWD (89%), in opposition to ISS (3.2%) in our cohort. The use of SH/H SDS as a selection criterion increases the frequency of SHOX mutation detection to 22% and should be used for selecting ISS children to undergo SHOX mutation molecular studies.     

Pulmonary hilar stereotactic body radiation therapy in the rat

Stereotactic Body Radiation therapy (SBRT) is an emerging modality of treatment for early stage non-small cell lung carcinoma. Concerns have arisen related to increased toxicities for medial tumors. We have developed a model of high dose, hypofractionated radiotherapy to the pulmonary hilum using the Leksell Gamma-Knife. Sprague-Dawley rats received hypofractionated SBRT to the unilateral lung hilum using a custom immobilization device on the Gamma Knife. Each animal was individually scanned, treatment planned, and treated with either two 4 mm or one 8 mm collimated shots at escalating doses of 20, 40, and 80 Gy to the 50% isodose volume, encompassing the right mainstem bronchus. All animals were carefully followed post-treatment and imaged by plain film and CT. In addition, histopathological analysis of all rats was performed at selected time points. Animals treated with 4 mm collimated shots demonstrated no appreciable changes on plain films or sequential, follow-up CT scans, or histopathologically. Animals irradiated with the 8 mm collimator were less active, gained weight at a reduced rate, and demonstrated histopathological changes in 7/34 animals six months post-irradiation. Cellular atypia and interstitial pneumonitis were found, three of the seven of the animals showed clear bronchial damage and two showed vascular damage. Significant volume and time effects were found. Utilizing a novel Gamma Knife based animal model to study SBRT toxicity, it was found that the bronchus will tolerate small volumes of very high dose radiotherapy. It was postulated that radiation of the surrounding support stroma and normal tissue are important in the etiology of bronchial or hilar damage.     

Methods to study adult hippocampal neurogenesis in humans and across the phylogeny

The hippocampus hosts the continuous addition of new neurons throughout life—a phenomenon named adult hippocampal neurogenesis (AHN). Here we revisit the occurrence of AHN in more than 110 mammalian species, including humans, and discuss the further validation of these data by single-cell RNAseq and other alternative techniques. In this regard, our recent studies have addressed the long-standing controversy in the field, namely whether cells positive for AHN markers are present in the adult human dentate gyrus (DG). Here we review how we developed a tightly controlled methodology, based on the use of high-quality brain samples (characterized by short postmortem delays and ≤24 h of fixation in freshly prepared 4% paraformaldehyde), to address human AHN. We review that the detection of AHN markers in samples fixed for 24 h required mild antigen retrieval and chemical elimination of autofluorescence. However, these steps were not necessary for samples subjected to shorter fixation periods. Moreover, the detection of labile epitopes (such as Nestin) in the human hippocampus required the use of mild detergents. The application of this strictly controlled methodology allowed reconstruction of the entire AHN process, thus revealing the presence of neural stem cells, proliferative progenitors, neuroblasts, and immature neurons at distinct stages of differentiation in the human DG. The data reviewed here demonstrate that methodology is of utmost importance when studying AHN by means of distinct techniques across the phylogenetic scale. In this regard, we summarize the major findings made by our group that emphasize that overlooking fundamental technical principles might have consequences for any given research field.     

Some aspects of the behavior of the hypothalamus-pituitary-adrenal axis in patients with uncomplicated Plasmodium falciparum malaria: Cortisol and dehydroepiandrosterone levels

We studied the behavior of cortisol and dehydroepiandrosterone (DHEA) in 24 patients with uncomplicated Plasmodium falciparum malaria of the Evandro Chagas Institute, Belém, Pará, Brazil. The patients were evaluated before treatment (Day 0), 24h after the beginning of medication (Day 1) and on Day 8 of follow-up (Day 7). Steroid levels were correlated with parasitemia, temperature and time of the disease. The levels of these hormones were found to be significantly higher on Day 0 than on Day 7, showing no correlation with parasitemia or temperature, but temperature had a positive effect on the correlation between cortisol and dehydroepiandrosterone. Cortisol was not correlated with the time of disease, but a significant negative correlation was observed between DHEA and time of disease on Day 7, suggesting a decline in the adrenal reserve of this steroid. In conclusion, an increase in cortisol and dehydroepiandrosterone is observed in patients with falciparum malaria, with these levels declining with decreasing parasitemia. The finding that temperature interfered with the correlation between cortisol and dehydroepiandrosterone suggests a common mechanism for the activation of these hormones in malaria.