Coordination of Pt(2+) to a family of tunable Schiff base proligands directs the 12-component self-assembly of disk-shaped Pt(4) rings in a head-to-tail fashion. Aggregation of these S(4) symmetric Pt(4) macrocycles into columnar architectures was investigated by dynamic and static light scattering, NMR spectroscopy, powder X-ray diffraction, and transmission electron microscopy. Data from these experiments support the formation of columnar architectures for all of the structures studied except when bulky tris(4-tert-butylphenyl)methyl substituents were present. In this case, aggregation was limited to dimers in CHCl(3) (K(dim) = 3200 +/- 200 L mol(-1) at 25 degrees C) and a thermodynamic analysis revealed that dimerization is an entropy driven process. Columnar architectures of Pt(4) rings with branched 2-hexyldecyl substituents organize into lyotropic mesophases in nonpolar organic solvents. These new self-assembled supramolecules are promising candidates to access nanotubes with multiple linear arrays of Pt(2+) ions.

The reactions between chalcogen tetrahalides (ChX(4); Ch = Se, Te; X = Cl, Br) and the neutral donors (n)Bu(3)P, Ph(3)P, or the N-heterocyclic carbene, 2,5-diisopropylimidazole-2-ylidene ((i)Pr(2)IM), have been investigated. In cases involving a phosphine, the chemistry can be understood in terms of a succession of two-electron redox reactions, resulting in reduction of the chalcogen center (e.g., Se(IV) --> Se(II)) and the oxidation of phosphorus to the [R(3)P-X] cation (P(III) --> P(V)). The stepwise reduction of Se(IV) --> Se(II) --> Se(0) --> Se(-II) occurs upon the successive addition of stoichiometric equivalents of Ph(3)P to SeCl(4), which can readily be monitored by 31P{(1)H} NMR spectroscopy. In the case of reacting SeX(4) with (i)Pr(2)IM, a similar two-electron reduction of the chalcogen is observed and there is the concomitant production of a haloimidazolium hexahaloselenate salt. The products have been comprehensively characterized, and the solid-state structures of [R(3)PX][SeX(3)] (9), [Ph(3)PCl](2)[TeCl(6)] (10), (i)Pr(2)IM-SeX(2) (11), and [(i)Pr(2)IM-Cl](2)[SeCl(6)] (12) have been determined by X-ray diffraction analysis. These data all support two electron redox reactions and can be considered in terms of the formal reductive elimination of X2, which is sequestered by the Lewis base.

Background:We recently introduced a clinical practice pathway for the management of asthma that uses the Pediatric Respiratory Assessment Measure (PRAM) to guide emergency department (ED) treatment and disposition. The pathway recommends discharge for patients who achieve improvement to PRAM <4 at 1 hour after the last bronchodilator. We evaluated practice variation and patient outcomes associated with PRAM-directed disposition recommendations. Methods: We conducted a retrospective cohort study of children aged 2 to 17 years treated for moderate asthma (PRAM score 4-7) using our asthma clinical pathway. We measured 1) the proportion of children discharged per pathway criteria who returned to our ED within 24 hours and 2) the proportion of children observed beyond the pathway discharge criteria who deteriorated (PRAM ≥4). Results: We analyzed 385 patient records from September 2013 to February 2015. Among 145 (37.7%) patients discharged per pathway criteria, 4 (4/145; 2.8%) returned within 24 hours. The remaining 240 (62.2%) were observed beyond the pathway discharge criteria; 76/240 (31.7%) had a subsequent deterioration (PRAM score ≥ 4) and 25/240 (10.4%) were hospitalized. Of those who deteriorated, 46/76 (60.5%) worsened within the first additional hour of observation. Conclusion:We observed significant deviation from our PRAM-directed pathway discharge criteria and that a significant proportion of observed patients experienced clinical deterioration beyond the first hour of observation. We recommend observing children with moderate asthma for 2 or 3 hours from last bronchodilator therapy if PRAM < 4 is maintained, to capture the majority (97.7% or 99.7%) of patients who require further intervention and hospitalization.

Initial presentationA 12-year-old boy presented with a two-day history of gross hematuria and vomiting. Further questioning revealed a one-year history of position-induced paroxysmal headaches, polyuria, polydipsia, nocturia, dehydration, and lethargy. He denied any syncopal episodes, palpitations, night sweats, blurry vision, or anxiety attacks. He was noted to have normal pubertal development. An abdominal ultrasound was performed, and showed an 8.1 x 7.5cm bladder mass on the posterior bladder wall with hypervascular components (Figure 1). The patient was brought to the operating theater for cystoscopy, which revealed a large, necrotic mass on the postero-lateral bladder wall. Bladder biopsy was performed. There were significant blood pressure fluctuations during the biopsy. Final pathology reported the mass to be a bladder paraganglioma (PGL).The patient received a two-week course of alpha-adrenergic blockade with Prazosin and Amlodipine for blood pressure control prior to definitive surgery. Echocardiogram did not reveal significant cardiomyopathy. PET/CT scan showed no evidence of metastatic disease, but avid F18-fludeoxyglucose ([F-18]FDG) uptake was noted at the tumor site (Figure 2). ManagementThe patient was brought back to operating theatre for treatment via partial cystectomy. The tumor was located near the right ureteric opening, and a ureteric stent was placed for 6 weeks. Pathology reported the resected PGL had negative surgical margins and no invasion into extravesicular fat. The patient was followed with urine metanephrine and blood pressure measurements every three months for surveillance. Subsequent medical genetics consultation revealed an underlying succinate dehydrogenase B (SDHB) gene mutation. First-degree patient relatives were subsequently investigated for the SDHB mutation.