Defining atypical croup: A case report and review of the literature.

BACKGROUND: Croup is a common respiratory illness in children. It presents with a barky cough, stridor and hoarseness occurring secondary to inflammation of the subglottis and larynx. The clinical course of croup is well-described, however atypical presentations pose a diagnostic and management challenge. OBJECTIVES: This case report and systematic review aims to synthesize the published literature on the definition, diagnosis and treatment of atypical croup. STUDY SELECTION: Peer-reviewed journal publications in Ovid MEDLINE® and EMBASE from inception to January 1, 2019 in English, focusing on pediatric patients (<18 years of age) with diagnoses of atypical croup. DATA EXTRACTION: Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. RESULTS: Twelve studies involving 670 patients ranging from 6 months to 11 years of age presenting with atypical croup were selected. A variety of definitions of atypical croup were identified based on recurrence, duration of symptoms, severity, and etiology. Data on the incidence of atypical croup, the overall rates of intubation and tracheostomy, and patient characteristics leading to definitive airway management were not clearly characterized. LIMITATIONS: All studies were case series, case reports or retrospective chart reviews. CONCLUSIONS: Atypical croup is a poorly defined clinical entity that is used to describe recurrent, refractory, or croup-like illness that follows an uncharacteristic natural history. Our case presentation and accompanying literature review highlights the variable, but limited, information available on the diagnosis of atypical croup. Given the commonality of its use in clinical practice, we propose some guidelines around the use of the term 'atypical croup' as well as a management algorithm.

An evaluation of in-office flexible fiber-optic biopsies for laryngopharyngeal lesions.

BACKGROUND: Operative endoscopy and flexible fiber-optic in-office tissue biopsy are common techniques to assess suspicious laryngopharyngeal lesions. METHODS: The primary outcome was the delay to the initiation of treatment. Secondary outcomes were delay to biopsy, histopathological diagnosis, and assessment at a multidisciplinary oncology clinic. A retrospective analysis was performed to assess the relative delays between these approaches to biopsy of laryngopharyngeal lesions. RESULTS: There were 114 patients in the study cohort; 44 in-office and 70 operative endoscopic biopsies). The mean delay from consultation to biopsy was 17.4 days for the operative endoscopy group and 1.3 days for the in-office group. The mean delay from initial otolaryngology consultation to initiation of treatment was 51.7 days and 44.6 days for the operative endoscopy and in-office groups, respectively. CONCLUSION: In-office biopsy reduced the time from initial consultation to biopsy. The temporal gains via in-office biopsy did not translate into faster access to treatment. This outcome highlights the opportunity to improve access to treatment for patients with early diagnosis.

Arenechromiumtricarbonyl complexes of silyl(germyl)(stannyl)- and silyl(germyl)(plumbyl)methanes including unexpected formation of arenechromiumtricarbonyldimethylsilanol, (eta-C(6)H(5))Cr(CO)(3)SiMe(2)OH.

Treatment of PhMe(2)SiCH(2)GeMe(3) (1) with t-BuLi followed by addition of Me(3)ECl, E = Sn, Pb, results in the formation of phenylsilyl(germyl)stannyl- and phenylsilyl(germyl)plumbyl-methanes, PhMe(2)Si(Me(3)Ge)(EMe(3))CH, E = Sn (2), Pb (3). The thermal reaction of 1, 2 and 3 with Cr(CO)(6) yields the corresponding aryl-Cr(CO)(3) analogs, {(eta(6)-C(6)H(5))Cr(CO)(3)}Me(2)Si(Me(3)Ge)CH(2) (4) and {(eta(6)-C(6)H(5))Cr(CO)(3)}Me(2)Si(Me(3)Ge)(EMe(3))CH, E = Sn (5), Pb (6). The thermal treatment of 2 with Cr(CO)(6) in wet THF/di-n-butyl ether mixture results in the formation of the arenechromiumtricarbonyl silanol {(eta(6)-C(6)H(5))Cr(CO)(3)}Me(2)SiOH (7) which exhibits amphiphilic character, forming H-bonded chains in the solid state in a head-to-head arrangement of the areneCr(CO)(3) units.

Intramolecular chalcogen-tin interactions in [(o-MeEC6H4)CH2]2SnPh(2-n)Cl(n) (E = S, O, CH2; n = 0, 1, 2) and intermolecular chlorine-tin interactions in the meta- and para-methoxy isomers.

Organotin(IV) compounds of the type [(o-MeEC(6)H(4))CH(2)](2)SnPh(2-n)Cl(n) were synthesized, E = O, n = 0 (1), n = 1 (2), and n = 2 (3); E = S, n = 0 (4), n = 1 (5), and n = 2 (6); and E = CH(2), n = 0 (7), n = 1 (8), and n = 2 (9). The dichloro compounds 3 and 6 have been investigated by single-crystal X-ray diffraction and exhibit bicapped tetrahedral geometry at the tin atom as a consequence of significant intramolecular Sn...O (3) and Sn...S (6) secondary bonding, in monomolecular units. Compound 3, when crystallized from a hexane/THF solvent mixture, shows two different conformers, 3' and 3'', in the crystal structure; 3' has two equivalent Sn...O interactions, while 3'' has two nonequivalent Sn...O interactions. Upon the recrystallization of 3 from hexane, only a single structural form is observed, 3'. The Sn...E distances in 3', 3'', and 6 are 71.3, 73.5 and 72.9, and 76.3% of the SigmavdW radii, respectively. The meta- and para-substituted isomers of 3 (10, 11) exhibit a distortion at the tin atom due to self-association via intermolecular Sn...Cl interactions, resulting in polymeric structures. (119)Sn NMR spectroscopy suggests that the intramolecular Sn...E interactions persist in solution for the dichloride compounds 3 and 6.

Synthesis and cyclic voltammetric studies of diiron complexes, ER(2)[(eta-C(5)H(4))Fe(L(2))Me](2) (E = C, Si, Ge, Sn; R = H, alkyl; L(2) = diphosphine] and (eta-C(5)H(5))Fe(L(2))ER(2)Fc [Fc = (eta-C(5)H(4))Fe(eta-C(5)H(5))].

The cyclic voltammetric studies on ER(2)[(eta(5)-C(5)H(4))Fe(L(2))Me](2) (L(2) = dppe; ER(2) = CH(2) (1a), SiMe(2) (2a), GeMe(2) (3a), SnMe(2) (4a) revealed two well resolved reversible waves [(1)E(1/2) = -0.33 V, (2)E(1/2) = -0.20 V (for 1a); (1)E(1/2) = -0.35 V, (2)E(1/2) = -0.21 V (for 2a);(1)E(1/2) = -0.36 V, (2)E(1/2) = -0.23 V (for 3a);(1)E(1/2) = -0.36 V, (2)E(1/2) = -0.22 V (for 4a)] in CH(2)Cl(2) suggesting electronic communication between two iron centers which is seen for the first time in this family of organometallic complexes. The resolution between two reversible waves increases in the order of 1a < 2a < 3a < 4a; however, coordinating solvents such as pyridine, PhCN, DMSO and DMF decreased these interactions attributable to the stabilization of cationic species formed after the first oxidation. UV/Vis spectroelectrochemistry of 1a-4a revealed two distinct absorbance patterns for both redox processes and reflected the stepwise oxidation. Homobimetallic complexes containing ferrocenyl groups, (eta(5)-C(5)H(5))Fe(L(2))ER(2)Fc [ER(2) = none, L(2) = cis-dppen (5a), ER(2) = SiMe(2), L(2) = cis-dppen (6a), dppm (6b); ER(2) = GeMe(2), L(2) = cis-dppen (7a), dppm (7b); ER(2) = Sn(t)Bu(2), L(2) = dmpe (8a); Fc = (eta(5)-C(5)H(4))Fe(eta(5)4-C(5)H(5))] were prepared and studied in terms of electrochemistry. The cyclic voltammogram of 5a exhibited two well resolved one electron reversible waves at (1)E(1/2) = -0.21 V and (2)E(1/2) = 0.58 V corresponding to oxidation of the Fe(P-P) and Fc iron atoms respectively. Other complexes in this series (6a/6b, 7a/7b, 8a) containing direct Fe-E-Fc (E = Si, Ge and Sn) bridging units were not stable under electrochemical conditions and rupture of the Fe-E bonds was observed.

Single-crystal to single-crystal phase transitions of bis(N-phenylisonicotinamide)silver(I) nitrate reveal cooperativity properties in porous molecular materials.

Two single-crystal to single-crystal phase transitions in trans-[Ag(NPI)(2)](NO(3)).2CH(3)OH (), (NPI = N-phenylisonicotinamide) were characterized with X-ray crystallography; the first transition is reversible and arises from a desolvation transition induced by vacuum and generated ; the second transition was induced by heat at 140 degrees C and generated .

Intramolecular chalcogen-tin interactions in (o-MeE-C6H4)CH2SnPh3-nCln (E = S, O; n = 0, 1, 2), characterized by X-ray diffraction and 119Sn solution and solid-state NMR.

Organotin(IV) compounds of the type (o-MeE-C6H4)CH2SnPh3-nCln were synthesized, E = O, n = 0 (1), n = 1 (2), n = 2 (3) and E = S, n = 0 (4), n = 1 (5), n = 2 (6). The complexes exhibit significant trigonal bipyramidal pentacoordination at tin as a consequence of intramolecular Sn-O (1-3) and Sn-S (4-6) interactions upon substitution of the phenyl groups by chloro groups. The intramolecular Sn-O distances in 1, 2, and 3 are 83%, 75%, and 79% of the sum of the van der Waals radii. The equivalent Sn-S values for 4, 5, and 6 are 90%, 73%, and 71%, respectively. The geometry of compound 3 is complicated by intermolecular dimerization via bridging chlorines creating a distorted octahedral geometry at tin. The related dichloro sulfur compound 6 also exhibits an intermolecular association in the form of Sn-Cl-H hydrogen bonding leading to a polymeric structure in the solid state. CPMAS 119Sn NMR spectroscopy suggests that the intramolecular Sn-E interactions persist in solution and also facilitated the discovery of a new crystalline form of 4, 4', that contains a Sn-S distance which is 95% the sum of the van der Waals radii.

Synthesis, structural and spectroscopic characterization, catalytic properties, and thermal transformations of new cyclic di- and trisiloxanediolato tantalum complexes.

The reaction between Ta(OEt)5 and 1,1,3,3-tetramethyl-1,3-disiloxanediol, (HOSiMe2OSiMe2OH), leads to new siloxy complexes in which the dimeric nature of Ta(OEt)5 is maintained with both bridging ethoxide and disiloxanediolato bridges. With equal amounts of the reagents, two terminal OEt groups are replaced to form [Ta(OEt)2]2(mu-OEt)2(mu-OSiMe2OSiMe2O)2, 1, whereas with an excess of diol, the remaining terminal OEt groups are also replaced but with a trisiloxanediolato unit to form [Ta(OSiMe2OSiMe2OSiMe2O)]2(mu-OEt)2(mu-OSiMe2OSiMe2O)2, 2. Complexes 1 and 2 catalyze the transformation of HOSiMe2OSiMe2OH to polysiloxanes. Thermal treatment of 1 results in the formation of a 1:2 mixture of Ta2O5/SiO2; no new phases are observed. The molecular structures of 1 and 2 are confirmed by X-ray crystallography.

Investigating bidentate and tridentate carbamoylmethylphosphine oxide ligand interactions with rare-Earth elements using electrospray ionization quadrupole ion trap mass spectrometry.

Electrospray ionization (ESI) quadrupole ion trap mass spectrometry (QIT-MS) and collisionally activated dissociation (CAD) were used to evaluate the rare-earth binding properties of two hydrophobic carbamoylmethylphosphine oxide (CMPO) ligands, the normal bidentate variety, (t-BuC6H4)2P(O)CH2C(O)N(i-Bu)2 (A), a new potentially tridentate extractant, (t-BuC6H4)2P(O)CH[CH2C(O)N(i-Bu)2]C(O)N(i-Bu)2 (B), and tributyl phosphate. The mass spectral results obtained from analysis of 1% HNO3/methanol solution containing the ligands and dissolved lanthanide salts reveal that the favorable stoichiometries of the ligand/metal/nitrate complexes are 2:1:2 for the bidentate ligand A, 1:1:2 for the tridentate ligand B, and 3:1:2 for the monodentate tributyl phosphate. These observed stoichiometries correlate with the number of available binding sites on each ligand as well as with potential steric effects. Energy-variable collisionally activated dissociation experiments showed that for the 2:1:2 complexes involving ligand A or B, as the ionic radius of the bound metal decreased, the removal of nitric acid required less energy and resulted in less extensive spontaneous solvent coordination. This experimental trend suggests that, as the ionic radius of the lanthanide ion decreases, a pair of the carbamoylmethylphosphine ligands is able to more completely solvate the bound metal ion thereby weakening the nitrate-metal interaction.

A new synthetic route to bulky "second generation" tris(imidazol-2-ylidene)borate ligands: synthesis of a four coordinate iron(II) complex.

A bulky tripodal tris(carbene)borate ligand, prepared from 1-tert-butylimidazole, is cleanly transferred to iron(II) by a magnesium reagent.

Isolation and ring-opening of new 1-sila-3-metallacyclobutanes (eta 5-C5H4Fe)(CO)2CH2SiR2 leading to a new class of organometallic polymer.

Treatment of FpCH2SiR2Cl [Fp = (eta5-C5H5)Fe(CO)2] with lithium diisopropylamide leads to the formation of new metallacycle complexes. When R2 = Me2 and MenBu, these ring-open to form a new class of organometallic polymer. When R2 = nBu2, the metallacycle resists ring-opening and may be structurally characterized as the Ph3P-substituted species.

Synthesis of furanophane derivatives through [8+2]-cycloaddition of dienylisobenzofurans and alkynes.

The coupling of various dienylisobenzofurans with dimethyl acetylenedicarboxylate (DMAD) has been examined. In most cases, this reaction proceeds via [8+2]-cycloaddition to afford furan-bridged decatetraene ring systems. The major competing reaction pathway is [4+2]-cycloaddition between DMAD and the isobenzofuran nucleus. Isobenzofuran intermediates were generated using either a chromium carbene-based method or an acid-catalyzed method.

Synthesis and structural characterization of trinuclear Cu(II)-pyrazolato complexes containing mu(3)-OH, mu(3)-O, and mu(3)-Cl ligands. Magnetic susceptibility study of [PPN](2)[(mu(3)-O)Cu(3)(mu-pz)(3)Cl(3)].

The nine-membered [-Cu(II)-N-N-](3) ring of trimeric copper-pyrazolato complexes provides a sturdy framework on which water is twice deprotonated in consecutive steps, forming mu(3)-OH and mu(3)-O species. In the presence of excess chlorides the mu(3)-O(H) ligand is replaced by two mu(3)-Cl ions. The interconversion of mu(3)-OH and mu(3)-O and the exchange of mu(3)-O(H) and mu(3)-Cl are reversible, and the three species involved have been structurally characterized: [PPN][Cu(3)(mu(3)-OH)(mu-pz)(3)Cl(3)(thf)].CH(2)Cl(2) (1a), monoclinic P2(1)/n, a = 10.055(2) A, b = 35.428(5) A, c = 15.153(2) A, beta = 93.802(3) degrees, V = 5386(1) A(3), Z = 4; [Bu(4)N][Cu(3)(mu(3)-OH)(mu-pz)(3)Cl(3)] (1b), triclinic P-1, a = 9.135(2) A, b = 13.631(2) A, c = 14.510(2) A, alpha = 67.393(2) degrees, beta = 87.979(2) degrees, gamma = 80.268(3) degrees, V = 1643.2(4) A(3), Z = 2; [PPN](2)[Cu(3)(mu(3)-O)(mu-pz)(3)Cl(3)] (2), monoclinic P2/c, a = 12.807(2) A, b = 13.093(2) A, c = 23.139(4) A, beta = 105.391(3) degrees, V = 3741(1) A(3), Z = 2; [PPN](2)[Cu(3)(mu(3)-Cl)(2)(mu-pz)(3)Cl(3)].0.75H(2)O.0.5CH(2)Cl(2) (3a), triclinic P-1, a = 14.042(2) A, b = 23.978(4) A, c = 25.195(4) A, alpha = 76.796(3) degrees, beta = 79.506(3) degrees, gamma = 77.629(3) degrees, V = 7988(2) A(3), Z = 4; [Bu(4)N](2)[Cu(3)(mu(3)-Cl)(2)(mu-pz)(3)Cl(3)] (3b), monoclinic C2/c, a = 17.220(2) A, b = 15.606(2) A, c = 20.133(2) A, beta = 103.057(2) degrees, V = 5270(1) A(3), Z = 4; [Et(3)NH][Cu(3)(mu(3)-OH)(mu-pz)(3)Cl(3)(pzH)] (4), triclinic P-1, a = 11.498(2) A, b = 11.499(2) A, c = 12.186(2) A, alpha = 66.475(3) degrees, beta = 64.279(3) degrees, gamma = 80.183(3) degrees, V = 1331.0(5) A(3), Z = 2. Magnetic susceptibility measurements show that the three copper centers of 2 are strongly antiferromagnetically coupled with J(Cu-Cu) = -500 cm(-1).

Highly stereoselective syntheses of syn- and anti-1,2-amino alcohols.

The reduction of N-protected amino ketones can be carried stereoselectively to produce either the syn- or anti-amino alcohol diastereomer. Carbamate-protected amino ketones can be reduced predictably and selectively to anti-amino alcohols with LiAlH(O-t-Bu)3 in ethanol at -78 degrees C. N-Trityl-protected amino ketones can be reduced selectively to syn-amino alcohols with LiAlH(O-t-Bu)3 in THF at -5 degrees C.