Electric burn of the skull: treatment by applying trepanations and wound dressing. Illustrative case.

BACKGROUND: Although electric injuries to human tissue are uncommon in contemporary times, their occurrence implies a high degree of morbidity and mortality. These are primarily attributed to the impact of electric current on cellular membranes, resulting in the disruption of ionic changes. OBSERVATIONS: In this paper, the authors present the case of an electric burn on the skull in a 50-year-old male, treated by utilizing trepanation and daily sterile wound dressing. This approach differs from the conventional treatment involving tissue grafts. LESSONS: Although the techniques utilized in this case are not commonly chosen as the initial treatment option, they have demonstrated effectiveness. Despite the absence of tissue flaps or grafts, satisfactory coverage of the skull cap was achieved.

Crystal structure of an anhydrous form of trehalose: structure of water channels of trehalose polymorphism.

alpha, alpha-Trehalose (trehalose) is a nonreducing disaccharide of glucose and is accumulated at high concentrations in some anhydrobiotic organisms, which can survive without water for long periods and rapidly resume active metabolism upon hydration. Although it has been proposed that the intriguing mechanism of bioprotection in anhydrobiosis is conferred by a water channel, details of such a channel have yet to be revealed. We determined the crystal structure of a trehalose anhydrate to further understand the relationship between the structure of water channels and the trehalose polymorph. The space group was identical to that of the dihydrate and the lattice constants were also very similar. Among the five intermolecular hydrogen bonds between the trehalose molecules, four were preserved in the anhydrate. If dehydration of the dihydrate is slow and/or gentle enough to preserve the hydrogen bonds, transformation from the dihydrate to the anhydrate may occur. There are two different holes, hole-1 and hole-2, along one crystal axis. Hole-1 is constructed by trehalose molecules with a screw diad at its center, while hole-2 has a smaller diameter and is without a symmetry operator. Because of the screw axis at the center of hole-1, hollows are present at the side of the hole with diameters roughly equal to that of hole-1. Hole-1 and side pockets followed by hollows correspond to the positions of two water molecules of the dihydrate. The side hollows of the water channel are also observed in the water-filled hole of the dihydrate. Consequently, hole-1 is considered to be a one-dimensional water channel with side pockets. We also calculated molecular and crystal energies to examine the rapid water uptake of the anhydrate. It was demonstrated that the intermolecular interactions in the anhydrate were weaker than in the other anhydrous form, and probably also than those in amorphous trehalose. The anhydrate provides water capture for another solid form and gives protection from water uptake. These structural properties of the anhydrate may elucidate bioprotection in anhydrobiosis.

Circumferential ablation of Barrett's esophagus that contains high-grade dysplasia: a U.S. Multicenter Registry.

BACKGROUND: The management strategies for Barrett's esophagus (BE) that contains high-grade dysplasia (HGD) include intensive endoscopic surveillance, photodynamic therapy, thermal ablation, EMR, and esophagectomy. OBJECTIVE: To assess the safety and effectiveness of endoscopic circumferential balloon-based ablation by using radiofrequency energy for treating BE HGD. DESIGN: Multicenter U.S. registry. SETTING: Sixteen academic and community centers; treatment period from September 2004 to March 2007. PATIENTS: Patients with histologic evidence of intestinal metaplasia (IM) that contained HGD confirmed by at least 2 expert pathologists. A prior EMR was permitted, provided that residual HGD remained in the BE region for ablation. INTERVENTION: Endoscopic circumferential ablation with follow-up esophageal biopsies to assess the histologic response to treatment. OUTCOMES: Histologic complete response (CR) end points: (1) all biopsy specimen fragments obtained at the last biopsy session were negative for HGD (CR-HGD), (2) all biopsy specimens were negative for any dysplasia (CR-D), and (3) all biopsy specimens were negative for IM (CR-IM). RESULTS: A total of 142 patients (median age 66 years, interquartile range [IQR] 59-75 years) who had BE HGD (median length 6 cm, IQR 3-8 cm) underwent circumferential ablation (median 1 session, IQR 1-2). No serious adverse events were reported. There was 1 asymptomatic stricture and no buried glands. Ninety-two patients had at least 1 follow-up biopsy session (median follow-up 12 months, IQR 8-15 months). A CR-HGD was achieved in 90.2% of patients, CR-D in 80.4%, and CR-IM in 54.3%. LIMITATIONS: A nonrandomized study design, without a control arm, a lack of centralized pathology review, ablation and biopsy technique not standardized, and a relatively short-term follow-up. CONCLUSIONS: Endoscopic circumferential ablation is a promising modality for the treatment of BE that contains HGD. In this multicenter registry, the intervention safely achieved a CR for HGD in 90.2% of patients at a median of 12 months of follow-up.

Syntheses and physical properties of quasi-one-dimensional halogen-bridged Cu(II)(-)Pt(IV) mixed-metal complexes [Cu(chxn)(2)][PtX(2)(chxn)(2)]X(4).

Quasi-one-dimensional halogen-bridged Cu(II)-Pt(IV) mixed-metal complexes of the form [Cu(chxn)(2)][PtX(2)(chxn)(2)]X(4), where chxn = 1R,2R-diaminocyclohexane and X is either Cl or Br, have been synthesized. The crystal structures of these compounds have been determined by single-crystal X-ray diffraction. The Cl-bridged compound crystallizes in the space group I222 with dimensions a = 24.237(1) A, b = 5.103(1) A, c = 6.854(1) A, and V = 847.7(1) A(3) and with Z = 1. The Br-bridged complex crystallizes in the space group I222 with dimensions a = 23.700(8) A, b = 5.344(5) A, c = 6.978(8) A, and V = 883.8(8) A(3) and with Z = 1. These structures are isomorphic to each other and to homometal [Pt(chxn)(2)][PtX(2)(chxn)(2)]X(4) complexes. In these complexes, the planar [Cu(chxn)(2)] and the octahedral [PtX(2)(chxn)(2)] groups are stacked alternatively with the axial bridging halogen ions, forming linear chain structures. The neighboring [Cu(chxn)(2)] and [PtX(2)(chxn)(2)] moieties along the chains are linked by hydrogen bonds between amino hydrogens and the counteranions (X). Moreover, there are hydrogen bonds among the neighboring chains that form a two-dimensional hydrogen-bonded network parallel to the bc plane. Therefore, the Cu(II) and Pt(IV) units are two-dimensionally ordered. The b axes correspond to the Cu(II)-Pt(IV) separations, which are shorter than those of [Pt(chxn)(2)][PtX(2)(chxn)(2)]X(4) due to the smaller ionic radius of the Cu(II) ions. In the XP spectra, the Pt(IV) 4f(7/2) and Pt(IV) 4f(5/2) binding energies in homometal [Pt(chxn)(2)][PtX(2)(chxn)(2)]X(4) are lower than those of [Cu(chxn)(2)][PtX(2)(chxn)(2)]X(4) (X = Cl and Br), indicating that the electron-phonon interaction in Cu(II)-Pt(IV) compounds is stronger than that in Pt(II)-Pt(IV) compounds. In the Raman spectra, nu(Pt(IV)(-)X) of the homometal Pt(II)-Pt(IV) complexes is lower than that of the Cu(II)-Pt(IV) complexes, indicating again that the electron-phonon interaction in Cu(II)-Pt(IV) compounds is stronger than that of Pt(II)-Pt(IV) compounds. The temperature-dependent magnetic susceptibilities of the Cu(II)-Pt(IV) complexes show weak antiferromagnetic interactions between Cu(II) components along the chain axes.

Daphnicyclidins A-H, novel hexa- or pentacyclic alkaloids from two species of Daphniphyllum.

Eight highly modified Daphniphyllum alkaloids with unprecedented fused hexa- or pentacyclic skeletons, daphnicyclidins A-H (1-8), have been isolated from the stems of Daphniphyllum humile and D.teijsmanni, and their structures were elucidated on the basis of spectroscopic data and chemical means. The stereochemistry was elucidated by combination of NOESY correlations, X-ray crystallographic data, and CD analyses.

Synthesis, structure, and reactions of (acylimino)triaryl-lambda(5)-bismuthanes: first comparative study of the (acylimino)pnictorane series.

The synthesis, structure, and reactions of (acylimino)triaryl-lambda(5)-bismuthanes and a comparative study of the structure and reactivity of a series of (acylimino)pnictoranes are reported. Treatment of ortho-substituted triarylbismuth dichlorides 1 (Ar(3)BiCl(2); Ar = 2-MeC(6)H(4), 2-MeOC(6)H(4), 2,4,6-Me(3)C(6)H(2)) with amides 2 (H(2)NCOR; R = CF(3), CCl(3), 3,5-(CF(3))(2)C(6)H(3)) in the presence of 2.2 equiv of KO-t-Bu in dichloromethane afforded (acylimino)triaryl-lambda(5)-bismuthanes 3 (Ar(3)Bi=NCOR) in yields of 77-96%. The ortho-substituted aryl ligands and the electron-withdrawing N-substituents afford kinetic and thermodynamic stabilization, respectively, to the reactive Bi=N bond. The structures and properties of a series of (acylimino)pnictoranes (Ar(3)M=NCOR and H(3)M=NCOCF(3); M = P, As, Sb, Bi) are compared by IR and (13)C and (15)N NMR, X-ray crystallography, and ab initio molecular orbital calculations. It was found that the contribution of the M(+)-N=C-O(-) canonical form becomes more prominent and the single-bond character of the M=N bond increases progressively as the pnictogen atom becomes heavier. The Bi=N bond of (acylimino)-lambda(5)-bismuthanes 3 possesses a highly polarized single-bond character, probably due to the differences in orbital size and electronegativity between the bismuth and nitrogen atoms. Thermal decomposition of (aroylimino)triaryl-lambda(5)-bismuthane 3f (o-Tol(3)Bi=NCOAr; Ar = 3,5-(CF(3))(2)C(6)H(3)) produces a gel in dry conditions or aniline 12 (ArNH(2)) in slightly wet conditions with a good recovery of tris(2-methylphenyl)bismuthane (4a). It is likely that the aryl isocyanate 13 (ArNCO) is produced during the thermolysis via a concerted C --> N migration of the Ar group with an elimination of the triarylbismuthonio group as bismuthane 4a. (Acylimino)triaryl-lambda(5)-bismuthanes 3 oxidize 1,1,2,2-tetraphenylethanediol, benzenethiol, methanol, and ethanol to benzophenone, diphenyl disulfide, methyl formate, and acetaldehyde, respectively, in two different reaction pathways depending on the structure of the substrates. Compound 3d (o-Tol(3)Bi=NCOCCl(3)) transfers the nitrenoid moiety to triphenylphosphane, triphenylarsane, and tris(2-methylphenyl)stibane to give the corresponding (acylimino)pnictoranes (Ar(3)M=NCOCl(3); M = P, As, Sb) and 4a, suggesting that 3d is thermodynamically much less stable than their lighter pnictogen counterparts. The copper-catalyzed decomposition of 3 (o-Tol(3)Bi=NCOR) afforded N-acyl-o-toluidines 18 (o-TolNHCOR) via a Bi --> N migration of the tolyl group. The observed reactivities of (acylimino)triaryl-lambda(5)-bismuthanes 3 demonstrate a good leaving ability of the bismuthonio group.

Enantioselective fluorination mediated by cinchona alkaloid derivatives/Selectfluor combinations: reaction scope and structural information for N-fluorocinchona alkaloids.

Cinchona-alkaloid/Selectfluor combinations efficiently fluorinate a variety of carbonyl compounds in a highly enantioselective manner to furnish chiral alpha-fluorocarbonyl compounds. The DHQB/Selectfluor combination is effective for the enantioselective fluorination of indanones and tetralones 1 in up to 91% ee. The first enantioselective syntheses of chiral derivatizing reagents 3 was accomplished with high ee and in high chemical yields by the DHQDA/Selectfluor combination. 3-Fluorooxindoles 7 were prepared with ee up to 83% using the (DHQ)2AQN/Selectfluor or the (DHQD)2PYR/Selectfluor combination. Since the combinations are conveniently prepared in situ from readily available reagents, the present system represents a practical method for enantioselective fluorination. X-ray crystallography and 1H NMR analyses of the cinchona alkaloids/Selectfluor combination have established that the species that mediate this novel reaction are N-fluoroammonium cinchona alkaloid tetrafluoroborates, which adopt open conformations.

A double-functionalized cyclen with carbamoyl and dansyl groups (cyclen = 1,4,7,10-tetraazacyclododecane): a selective fluorescent probe for Y(3+) and La(3+).

A cyclen (=1,4,7,10-tetraazacyclododecane) doubly functionalized with three carbamoylmethyl groups and one dansylaminoethyl (dansyl = 2-(5-(dimethylamino)-1-naphthalenesulfonyl) group (L(2) = 1-(2-(5-(dimethylamino)-1-naphthalenesulfonylamido)ethyl)-4,7,10-tris(carbamoylmethyl)-cyclen) was synthesized and characterized. Potentiometrtic pH titration and UV spectrophotometric titration of L(2) served to determine deprotonation of the pendant dansylamide (L(2) --> H(-1)L(2)) with a pK(a) value of 10.6, while the fluorometric titration disclosed a pK(a) value of 8.8 +/- 0.2, which was assigned to the dansyl deprotonation in the excited state. The 1:1 M(3+)-H(-1)L(2) complexation constants (log K(app) = 6.0 for Y(3+) and 5.2 for La(3+), where K(app)(M-H(-1)L(2)) = [M(3+)-H(-1)L(2)]/[M(3+)](free)[L(2)](free) (M(-1)) at pH 7.4) were determined by potentiometric pH titration and UV and fluorescence spectrophotometric titrations (excitation at 335 nm and emission at 520 nm) in aqueous solution (with I = 0.1 (NaNO(3))) and 25 degrees C. The X-ray structure analysis of the Y(3+)-H(-1)L complex showed nine-coordinated Y(3+) with four nitrogens of cyclen, three carbamoyl oxygens, and the deprotonated nitrogen and a sulfonyl oxygen of the dansylamide. The crystal data are as follow: formula C(28)H(49)N(11)O(13.5)SY (Y(3+)-H(-1)L(2) x 2(NO(3)(-)) x 2.5H(2)O), M(r) = 876.73, monoclinic, space group P2(1)/n (No. 14), a = 18.912(3) A, b = 17.042(3) A, c = 24.318(4) A, beta = 95.99(1) degrees, V = 7794(2) A(3), Z = 8, R1 = 0.099. Upon M(3+)-H(-1)L(2) complexation, the dansyl fluorescence greatly increased (8.6 and 3.8 times for Y(3+) and La(3+), respectively) in aqueous solution at pH 7.4. Other lanthanide ions also yielded Ln(3+)-H(-1)L(2) complexes with similar K(app) values, although all the dansyl fluorescences were weakly quenched. On the other hand, zinc(II) formed only a 1:1 Zn(2+)-L(2) complex at neutral pH with negligible fluorescence change. The X-ray crystal structure of the Zn(2+)-L(2) complex confirmed the pendant dansylamide being noncoordinating. The crystal data are as follow: formula C(28)H(51)N(11)O(14)SZn (Zn(2+)-L(2) x 2(NO(3)(-)) x 3H(2)O), M(r) = 863.22, monoclinic, space group C2/n (No. 15), a = 35.361(1) A, b = 13.7298(5) A, c = 18.5998(6) A, beta = 119.073(2) degrees, V = 7892.3(5) A(3), Z = 8, R1 = 0.084. Other divalent metal ions did not interact with L(2) at all (e.g., Mg(2+) and Ca(2+)) or interacted with L(2) with the dansyl fluorescence quenched (e.g., Cu(2+)).

A novel intramolecular through-space interaction between F and CN: a strategy for the conformational control of an acyclic system.

X-Ray crystallographic analyses of fluorocyanides anti-1 and 2 revealed a novel intramolecular through-space interaction between F and CN in an acyclic system, which was applied to a stereoselective protonation of acyclic fluorocyanides 2 having flexible conformation.

Synthesis and antibacterial activity of new 1beta-methylcarbapenems having the potential for intramolecular nonbonded S...O interactions.

Mercaptoacetyliminothiadiazoline derivatives (19, 20) useful for the pendant moiety of 1beta-methylcarbapenem antibiotics were efficiently synthesized. Acetyl derivative (18) of 20 was submitted to X-ray analysis, and a significant nonbonded S...O close contact was recognized in the crystallographic structure. New 1beta-methylcarbapenems (5, 6) were synthesized by exploiting 19 and 20, and exhibited considerable antibacterial activities in vitro.

Synthesis and structure of 4-O,6-O-glycosylidene glycosides.

Interglycosidic spiro ortho esters (9-20) were efficiently prepared from methyl 2,6-di-O-benzylgluco- or galactopyranoside and various sugar lactones in the presence of methoxytrimethylsilane and a catalytic amount of trimethylsilyl triflate. All of the prepared sugar ortho esters possess perhydrospiro[2H-pyran-2,2'-pyrano[3,2-d][1,3]dioxin] ring systems commonly in their molecules and, remarkably, were afforded as single isomers. The configurations of the spiro centers in their molecules were determined or estimated by X-ray single crystallographic analysis and molecular modeling studies. By comparing the conformations of prepared ortho esters, we revealed that the difference in the stability between two possible isomers was principally caused from that between the spiro ring systems in their molecules in each case.

Intramolecular carbostannation reaction of active methine compounds with an unactivated C-C pi-bond mediated by SnCl(4)-Et(3)N

In the presence of SnCl(4) and Et(3)N, intramolecular carbostannation reaction of various active methine compounds having an unactivated alkenyl, alkynyl, or allenyl group proceeds in good yields with complete regioselectivity. The subsequent reaction of the resulting Sn intermediates with some electrophiles provides functionalized cyclopentane and cyclohexane derivatives.

A new quinolizidine alkaloid from the Papua New Guinean sponge Xestospongia exigua.

A new bis-quinolizidine alkaloid, xestosin A (1), possessing cis- and trans-quinolizidine nuclei, has been isolated from the Papua New Guinean sponge Xestospongia exigua. The structure was determined by spectrometric and single-crystal X-ray analyses.

Absolute stereochemistry of amphidinolides G and H.

[structure: see text] Absolute stereochemistry of amphidinolides G (1) and H (2), potent cytotoxic 27- and 26-membered macrolides, respectively, isolated from a marine dinoflagellate Amphidinium sp., was determined by X-ray diffraction analysis, synthesis of a degradation product (3) of 2, and interconversion between 1 and 2.

Structure and stereochemistry of the higher bile acid isolated from turtle bile: (22S,25R)-3 alpha,12 alpha,15 alpha,22-tetrahydroxy-5 beta-cholestan-26-oic acid.

The structure and stereochemistry of the higher bile acid, tetrahydroxyisosterocholanic acid (TISA), which was previously isolated from the bile of Amyda japonica (turtle) and proposed as a tetrahydroxyisosterocholanic acid, have been established as (22S,25R)-3 alpha,12 alpha,15 alpha,22-tetrahydroxy-5 beta-cholestan-26-oic acid by X-ray crystallographic analysis of its ethyl ester.

1:1 complexes of dimethylthio- and ethylenedithio-tetrathiafulvalenothioquinone-1,3-dithiolemethides with CuBr2 as a new type of pi/d molecular system.

The reaction of dimethylthio- (1) and ethylenedithio-tetrathiafulvalenothioquinone-1,3-dithiolemethides (2) with CuBr2 gave 1:1 complexes between the donors and CuBr2, 1.CuBr2 and 2.CuBr2, in which the Cu atom of CuBr2 binds to the thiocarbonyl S atom in 1 and 2. The electrical conductivity (sigma) of 1.CuBr2 at room temperature was ca. 10(-5) S cm-1, while a comparatively high value of 4.0 S cm-1 was obtained for 2.CuBr2, whose temperature dependence of sigma exhibited, however, semiconducting behavior with a very small activation energy of 0.18 eV. The observed paramagnetic susceptibilities (chi p's) of the Cu complexes were composed of both a component due to the localized Cu spins obeying the Curie-Weiss law and a temperature-independent chi p due to the conducting pi electrons on the 1- or 2-stacked columns. From the Curie constants obtained, the degrees of intramolecular electron transfer from 1 and 2 to CuBr2 moieties were estimated at ca. 90% and 60%, respectively. The small, negative Weiss temperature suggest very weak antiferromagnetic interactions among the Cu spins on the CuBr2 moieties.

A Cu(II)-mediated C-H oxygenation of sterically hindered tripyridine ligands to form triangular Cu(II)3 complexes.

Two sterically hindered tris-pyridyl methane ligands, tris(6-methyl-2-pyridyl)methane (L1) and bis(6-methyl-2-pyridyl)pyridylmethane (L2), are newly synthesized. Under aerobic conditions, Ln (n = 1 or 2) reacts with CuX2 (X = Cl or Br), oxygenated at the methine position to LnOH or LnOMe. The former alcoholate ligand creates trinuclear Cu(II) complexes [Cu3(X)(LnO)3](PF6)2 [(X, n) = (Br, 1) 1, (C1, 1) 2, (Br, 2) 3, or (C1, 2) 4] in which the alkoxide oxygen atoms bridge copper centers. The crystal structures of 1-4 are presented along with their magnetic susceptibility data. The weak antiferromagnetic coupling between the Cu(II) centers in this trinuclear arrangement is due to weak interaction of the magnetic orbitals (dz2) which are oriented along three alternate sides in a hexagon of the Cu3O3 core in 1-4. Under anaerobic conditions, L1 reacts with CuBr2 to form a square pyramidal complex [CuL1Br2] (9) with the ligand facially capping. [Cu(Br)2(L1OMe)] (10) was obtained after the suspension of 9 in MeOH was stirred under air for 48 h. In the presence of cyclohexene, 9 is converted to [Cu(Br)(L1)]m (m = 1 or 2) 5 quantitatively to give trans- 1,2-dibromocyclohexane, indicating that Br2 is generated during the reaction. The FAB MS spectrum of [18O]-1 prepared by the reaction of L1 with CuBr2 under 18O2 shows that the ligand of [18O]-1 is L1(18O-.) L1(18OH), L1OCD3, and bis(6-methyl-2-pyridyl) ketone were obtained from reaction of L1 with CuBr2 in CD3OD under 18O2. These results indicate that the origins of the O atom in L1OH and L1OMe are O2 and MeOH, respectively. On the basis of these results, a mechanism of the oxygenation of L1 in the present system will be proposed.