Doublecortin mutation leads to persistent defects in the Golgi apparatus and mitochondria in adult hippocampal pyramidal cells.

Human doublecortin (DCX) mutations are associated with severe brain malformations leading to aberrant neuron positioning (heterotopia), intellectual disability and epilepsy. DCX is a microtubule-associated protein which plays a key role during neurodevelopment in neuronal migration and differentiation. Dcx knockout (KO) mice show disorganized hippocampal pyramidal neurons. The CA2/CA3 pyramidal cell layer is present as two abnormal layers and disorganized CA3 KO pyramidal neurons are also more excitable than wild-type (WT) cells. To further identify abnormalities, we characterized Dcx KO hippocampal neurons at subcellular, molecular and ultrastructural levels. Severe defects were observed in mitochondria, affecting number and distribution. Also, the Golgi apparatus was visibly abnormal, increased in volume and abnormally organized. Transcriptome analyses from laser microdissected hippocampal tissue at postnatal day 60 (P60) highlighted organelle abnormalities. Ultrastructural studies of CA3 cells performed in P60 (young adult) and > 9 months (mature) tissue showed that organelle defects are persistent throughout life. Locomotor activity and fear memory of young and mature adults were also abnormal: Dcx KO mice consistently performed less well than WT littermates, with defects becoming more severe with age. Thus, we show that disruption of a neurodevelopmentally-regulated gene can lead to permanent organelle anomalies contributing to abnormal adult behavior.

Two cases of lupus vulgaris in childhood and review of the clinical challenges.

BACKGROUND: Lupus vulgaris (LV) is the most common form of cutaneous tuberculosis (TB) in Europe, nevertheless the overall incidence is low. It constitutes about 1.5% of all extra-pulmonary cases worldwide. A slight raise in TB incidence rates among children was recently registered in Germany, which can be explained by the increased immigration. PATIENTS AND METHODS: We present 2 cases of immigrated children who were diagnosed with Lupus vulagris, both clinically and histopathologically. Although the symptoms and the duration of the skin lesions were very different, both patients had a non-healing skin ulceration.In our cases cultures of the skin biopsy were positive for Mycobacterium tuberculosis and the lesions showed marked improvement in response to antituberculous treatment. In the first patient, it took 6 years between occurrence of skin lesions and final diagnosis. The second patient had an extracutaneous focus, namely abdominal TB. CONCLUSION: We report our experience and emphasize on recent advances in the diagnosis and treatment of paediatric skin TB.

Hippocampal development - old and new findings.

The hippocampus, derived from medial regions of the telencephalon, constitutes a remarkable brain structure. It is part of the limbic system, and it plays important roles in information encoding, related to short-term and long-term memory, and spatial navigation. It has also attracted the attention of many clinicians and neuroscientists for its involvement in a wide spectrum of pathological conditions, including epilepsy, intellectual disability, Alzheimer disease and others. Here we address the topic of hippocampal development. As well as original landmark findings, modern techniques such as large-scale in situ hybridizations, in utero electroporation and the study of mouse mutants with hippocampal phenotypes, add further detail to our knowledge of the finely regulated processes which form this intricate structure. Molecular signatures are being revealed related to field, intra-field and laminar cell identity, as well as, cell compartments expressing surface proteins instrumental for connectivity. We summarize here old and new findings, and highlight elegant tools used to fine-study hippocampal development.