Antecedent Minor Trauma and Hyperacute Presentations in Childhood Transverse Myelitis.

INTRODUCTION: Fibrocartilaginous embolism and spinal cord infarction may resemble transverse myelitis with antecedent minor trauma (sporting activity or minor falls) or with hyperacute (<12-hour) presentation. METHODS: Diagnostic criteria for fibrocartilaginous embolism and spinal cord infarction were applied to a 10-year (2007-2016) cohort of children aged 1 month to 16 years with transverse myelitis and clinical, laboratory, neuroimaging, and outcome data compared between those with and without antecedent minor trauma. RESULTS: Thirty-two children of median age 8.9 (range 2.7-15.8) years were included; 19 (59%) were female. Falls at home, school, or play (6 children, 60%), swimming (2, 20%), physical education (1, 10%), and caning (1, 10%) were antecedent events in 10 (31%) children. Six (19%) had hyperacute presentations. One patient met spinal cord infarction criteria; none had fibrocartilaginous embolism. Children with transverse myelitis and antecedent minor trauma had single, short spinal cord lesions (median 3 vertebral bodies) but without a specific neuroimaging lesion pattern. None had intervertebral disc abnormalities or brain involvement and were negative for myelin oligodendrocyte and aquaporin 4 antibodies. Twenty-five (86%) of 29 had cerebrospinal fluid inflammation, and 30 (94%) received immunotherapy. Thirty (97%) were followed for a median of 3.6 (0.1-10.2) years, with good outcome (modified Rankin Scale score 0-1) in the majority (80%). Four (75%) with hyperacute presentation had a good outcome (modified Rankin Scale score 0-1), but the patient with spinal cord infarction was the most disabled (modified Rankin Scale score 4). CONCLUSION: Minor trauma or hyperacute presentations does not always indicate fibrocartilaginous embolism or spinal cord infarction. Children with minor trauma preceding transverse myelitis have a distinct clinicoradiologic syndrome, with good outcome following immunotherapy.

Coexistence of two distinct G-quadruplex conformations in the hTERT promoter.

The catalytic subunit of human telomerase, hTERT, actively elongates the 3' end of the telomere in most cancer cells. The hTERT promoter, which contains many guanine-rich stretches on the same DNA strand, exhibits an exceptional potential for G-quadruplex formation. Here we show that one particular G-rich sequence in this region coexists in two G-quadruplex conformations in potassium solution: a (3 + 1) and a parallel-stranded G-quadruplexes. We present the NMR solution structures of both conformations, each comprising several robust structural elements, among which include the (3 + 1) and all-parallel G-tetrad cores, single-residue double-chain-reversal loops, and a capping A.T base pair. A combination of NMR and CD techniques, complemented with sequence modifications and variations of experimental condition, allowed us to better understand the coexistence of the two G-quadruplex conformations in equilibrium and how different structural elements conspire to favor a particular form.