Red Flags for early referral of people with symptoms suggestive of narcolepsy: a report from a national multidisciplinary panel

OBJECTIVE

Narcolepsy is a lifelong disease, manifesting with excessive daytime sleepiness and cataplexy, arising between childhood and young adulthood. The diagnosis is typically made after a long delay that burdens the disease severity. The aim of the project, promoted by the "Associazione Italiana Narcolettici e Ipersonni" is to develop Red Flags to detect symptoms for early referral, targeting non-sleep medicine specialists, general practitioners, and pediatricians.

MATERIALS AND METHODS

A multidisciplinary panel, including patients, public institutions, and representatives of national scientific societies of specialties possibly involved in the diagnostic process of suspected narcolepsy, was convened. The project was accomplished in three phases. Phase 1: Sleep experts shaped clinical pictures of narcolepsy in pediatric and adult patients. On the basis of these pictures, Red Flags were drafted. Phase 2: Representatives of the scientific societies and patients filled in a form to identify barriers to the diagnosis of narcolepsy. Phase 3: The panel produced suggestions for the implementation of Red Flags.

RESULTS

Red Flags were produced representing three clinical pictures of narcolepsy in pediatric patients ((1) usual sleep symptoms, (2) unusual sleep symptoms, (3) endocrinological signs) and two in adult patients ((1) usual sleep symptoms, (2) unusual sleep symptoms). Inadequate knowledge of symptoms at onset by medical doctors turned out to be the main reported barrier to diagnosis.

CONCLUSIONS

This report will hopefully enhance knowledge and awareness of narcolepsy among non-specialists in sleep medicine in order to reduce the diagnostic delay that burdens patients in Italy. Similar initiatives could be promoted across Europe.

Biochemical and molecular characterization of the novel BRAFV599Ins mutation detected in a classic papillary thyroid carcinoma

Activating mutations of the BRAF gene are the most common genetic alterations in papillary thyroid carcinomas (PTCs) and the T1799A transversion, resulting in BRAFV600E, appeared virtually unique in this cancer type. Here, we report on the identification in a classic PTC of a novel BRAF mutation, namely a 1795GTT insertion, resulting in BRAFV599Ins, and describe its biochemical and molecular characterization. Kinase assays carried out on BRAFV599Ins and BRAFV600E revealed a three- to five-fold increase in the enzymatic activity of both mutants with respect to BRAFWT. Similarly, evaluation of BRAF-induced phosphorylation of MEK, MAPK and RSK revealed a significant MAPK cascade activation in cells expressing BRAFV599Ins or BRAFV600E, but not in cells expressing BRAFWT. Molecular dynamic simulations showed a destabilization of the inactive conformation of the enzyme in both BRAFV599Ins and BRAFV600E mutants, but not in BRAFWT. The analysis of the interaction energies inside the catalytic site allowed to demonstrate the presence of repulsive electrostatic forces acting on the activation loop and moving from inward to outward of the mutant enzymes. Finally, focus assays in NIH-3T3 cells confirmed a high transformation rate in the cells transfected either with BRAFV599Ins or BRAFV600E. In conclusion, this study demonstrated that BRAFV599Ins, as BRAFV600E, is a 'gain of function' mutation, characterized by a constitutive catalytic activation, which accounts for its causative role in the studied PTC.

Accentuated response to phenylhydrazine and erythropoietin in mice genetically impaired for their GATA-1 expression (GATA-1(low) mice)

The response of mice genetically unable to up-regulate GATA-1 expression (GATA-1(low) mice) to acute (phenylhydrazine [PHZ]-induced anemia) and chronic (in vivo treatment for 5 days with 10 U erythropoietin [EPO] per mouse) erythroid stimuli was investigated. Adult GATA-1(low) mice are profoundly thrombocytopenic (platelet counts [x 10(9)/L] 82.0 +/- 28.0 vs 840 +/- 170.0 of their control littermates, P <.001) but have a normal hematocrit (Hct) (approximately.47 proportion of 1.0 [47%]). The spleens of these mutants are 2.5-fold larger than normal and contain 5-fold more megakaryocytic (4A5(+)), erythroid (TER-119(+)), and bipotent (erythroid/megakaryocytic, TER-119(+)/4A5(+)) precursor cells. Both the marrow and the spleen of these animals contain higher frequencies of burst-forming units-erythroid (BFU-E)- and colony-forming units-erythroid (CFU-E)-derived colonies (2-fold and 6-fold, respectively) than their normal littermates. The GATA-1(low) mice recover 2 days faster from the PHZ-induced anemia than their normal littermates (P <.01). In response to EPO, the Hct of the GATA-1(low) mice raised to.68 proportion of 1.0 (68%) vs the.55 proportion of 1.0 (55%) reached by the controls (P <.01). Both the GATA-1(low) and the normal mice respond to PHZ and EPO with similar (2- to 3-fold) increases in size and cellularity of the spleen (increases are limited mostly to cells, both progenitor and precursor, of the erythroid lineage). However, in spite of the similar relative cellular increases, the increases of all these cell populations are significantly higher, in absolute cell numbers, in the mutant than in the wild-type mice. In conclusion, the GATA-1(low) mutation increases the magnitude of the response to erythroid stimuli as a consequence of the expansion of the erythroid progenitor cells in their spleen.

Erythropoietin-dependent suppression of the expression of the beta subunits of the interleukin-3 receptor during erythroid differentiation

To clarify how erythroid cells lose their response to interleukin-3 (IL-3), we analyzed the expression of the alpha (alpha(IL-3)) and beta (beta(IL-3)/beta(com)) subunits of its receptor in a panel of murine cell lines immortalized at different stages of hemopoietic differentiation. The panel was composed by the mast cell line 32D and by its granulo-monocytic (32D GM), granulocytic (32D G), and erythroid (32D Epo1.1 and Epo) subclones. The 32D Epo cells grow only in erythropoietin (EPO) while the Epo1.1 subclone grows in either EPO or IL-3. The phenotype of these cells is that of early (expression of globins and erythroid-specific carbonic anhydrase II) and late (also expression of the erythroid-specific band 4.1 mRNA) erythroblasts when they grow in IL-3 or EPO, respectively. All the cell lines expressed comparable levels of alpha(IL-3). In contrast, the expression of beta(IL-3)/beta(com) was restricted to cells growing in IL-3 and was barely detectable in 32D Epo and 32D Epo1.1 cells growing in EPO. When switched from EPO to IL-3, 32D Epo1.1 cells expressed 10 times more beta(IL-3)/beta(com) by rapidly activating (within 1 h) their transcription rate. When reexposed to EPO, 32D Epo1.1 cells first expressed (1-6 h) more beta(IL-3)/beta(com) (2 times) but suppressed such an expression at later time points (by 48 h). The beta(IL-3)/beta(com) mRNA half-life was also different when 32D Epo1.1 cells grew in EPO or IL-3 (2-3 h vs >5 h, respectively). These results indicate that EPO specifically induces transcriptional and posttranscriptional downmodulation of beta(IL-3)/beta(com) expression in late erythroid cells.

In vivo expansion of purified hematopoietic stem cells transplanted in nonablated W/Wv mice

We have evaluated the in vivo amplification potential of purified murine hematopoietic stem cells, identified as Wheat Germ Agglutinin+ (WGA+), 15-1.1(-) , Rhodamine 123 Dull (Rho-dull) cells, by serial transplantation into stem cell defective nonmyeloablated W/Wv mice. C57BL Rho-dull cells (250/ 500 cells/mouse) permanently engrafted nonablated W/Wv mice as defined by the presence of > 95% red and > 20% white donor-derived circulating cells for at least 1.5 years following transplantation. At this time, approximately 61% of Rho-dull cells and all the Rho-bright progenitor and colony forming cells of the engrafted mice were found to be donor-derived by c-Kit genotyping and by their response to stem cell factor (SCF). Retransplantation of 250-1000 Rho-dull cells from primary into secondary W/Wv recipients generated C57BL hematopoiesis in 40%-64% of animals revealing the presence of donor derived hematopoietic stem cells (HSC) in the bone marrow of the primary recipients. One and half years after transplantation, the bone marrow of the secondary engrafted animals contained C57BL Rho-dull cells approximately = 51% by genotype), which were capable of reconstituting tertiary W/Wv recipients. In this respect, 25% of tertiary mice expressed C57BL hematopoiesis when transplanted with 250-1000 Rhodull cells purified from secondary W/Wv recipients. On the basis of the number of Rho-dull cells purified from a single mouse, we calculate that approximately 7.3x10(4) Rho-dull cells, which are genotypically and functionally defined as C57BL long-term repopulating stem cells, were generated in the marrow of reconstituted primary W/Wv recipients transplanted 1.5 years earlier with 250-500 C57BL Rho-dull cells. We conclude that murine HSC have extensive amplification capacity in nonmyeloablated animals.