Arthroscopic reconstruction for acromioclavicular joint dislocation.

We describe an arthroscopic reconstruction technique for acromioclavicular joint dislocation. Subsequent to Baum's first repair of the coracoclavicular complex in 1886, over 60 operative procedures have been described in the literature. This procedure is the first described arthroscopic approach used in reconstruction for acromioclavicular dislocation. It provides an anatomically correct and structurally sound reconstruction of the coracoclavicular ligament complex. This arthroscopic technique is also a cosmetically pleasing alternative to previously described open procedures for reconstruction of acromioclavicular joint dislocations. As with most arthroscopic procedures, this technique achieves its goals with minimal morbidity and violation of the surrounding soft tissues.

The 1,2,4-triazolyl cation: thermolytic and photolytic studies.

The generation of the 1,2,4-triazolyl cation (1) has been attempted by the thermolysis and photolysis of 1-(1,2,4-triazol-4-yl)-2,4,6-trimethylpyridinium tetrafluoroborate (2) and the thermolysis of 1- and 4-diazonium-1,2,4-triazoles, using mainly mesitylene as the trapping agent. Thermolysis of 2 gave mostly 1,2,4-triazole, together with 3-(1,2,4-triazol-4-yl)-2,4,6-trimethylpyridine, 4-(1,2,4-triazol-4-ylmethyl)-2,6-dimethylpyridine, and 4-(2,4,6-trimethylbenzyl)-2,6-dimethylpyridine. Thermolysis of each of the diazonium salts in the presence of mesitylene again gave mainly triazole together with very low yields of 1-(1,2,4-triazol-1-yl)-2,4,6-trimethylbenzene and the corresponding -4-yl isomer in about the same ratio. On the other hand, photolysis of 2 in mesitylene gave mainly 1-(1,2,4-triazol-1-yl)-2,4,6-trimethylbenzene. A photoinduced electron transfer from mesitylene to 2 has been observed and preliminary laser flash photolyses of 2 and the corresponding 2,4,6-triphenylpyridinium salt have been carried out. The observed transients are explained as arising from the first excited states of the pyridinium salts rather than from 1. Ab initio MO calculations are reported and indicate that the predicted electronic ground-state of the triazolyl cation is a triplet state of B1 symmetry with five pi electrons, which corresponds to a diradical cation (1c). Possible mechanisms for the formation of the various products are proposed.

Redetermination of CaMn2O4.

The title compound, calcium dimanganese tetraoxide, CaMn(2)O(4), was synthesized hydrothermally and is made up of edge-sharing Mn(3+) distorted octahedral layers and eight-coordinate Ca(2+) centered polyhedral layers.

Complexes of acridine and 9-chloroacridine with I2: formation of unusual I6 chains through charge-transfer interactions involving amphoteric I2.

Acridine and 9-chloroacridine form charge-transfer complexes with iodine in which the nitrogen-bound I2 molecule is amphoteric; one end serves as a Lewis acid to the heterocyclic donor, while the other end acts as a Lewis base to a second I2 molecule that bridges two acridine.I2 units. In the acridine derivative [(acridine.I2)2.I2, 1], the dimer has a "zigzag" conformation, while in the 9-chloroacridine derivative [(9-Cl-acridine.I2)2.I2, 2], the dimer is "C-shaped". The thermal decomposition of the two complexes is very different. Compound 1 loses one molecule of I2 to form an acridine.I2 intermediate, which has not been isolated. Further decomposition gives acridine as the form II polymorph, exclusively. Decomposition of 2 involves the loss of two molecules of I2 to form a relatively stable intermediate [(9-Cl-acridine)2.I2, 3]. Compound 3 consists of two 9-Cl-acridine molecules bridged through N...I charge-transfer interactions by a single I2 molecule. This compound represents the first known example, in which both ends of an I2 molecule form interactions in a complex that is not stabilized by the extended interactions of an infinite chain structure. The ability of the terminal iodine of an N-bound I2 to act either as an electron donor (complexes 1 and 2) or as an electron acceptor (complex 3) can be understood through a quantum mechanical analysis of the systems. Both electrostatic interactions and the overlap of frontier molecular orbitals contribute to the observed behavior.

Coordination polymers of copper(I) halides.

A total of 21 complexes of CuX (X = Cl, Br, I) with bridging ligand (B = 4,4'-dipyridyl (Bpy), pyrazine (Pyz), quinoxaline (Quin), phenazine (Phz), 1,4-diazabicyclo[2.2.2]octane (DABCO), and hexamethylenetetramine (HMTA)) have been synthesized. The products show two stoichiometries: [CuXB] (type 1) and [(CuX)2B] (type 2). Both types can be obtained for B = Bpy, depending on the conditions of preparation. In these cases, the type 2 stoichiometry is the kinetic product. Type 2 complexes only are found for B = Pyz (X = I), Quin, Phz, DABCO, and HMTA. Type 1 complexes form for Pyz (X = Cl, Br). Thermogravimetic analyses of the complexes reveal the general decomposition trend: 1 --> 2 --> [(CuX)2B(1/2)] --> CuX. The X-ray crystal structure of [CuBr(Pyz)] (type 1) features copper atoms bridged by Br and Pyz, forming 2D sheets of fused rectangular Cu4Br2(Pyz)2 units. The X-ray structure of [(CuI)2(Quin)] (type 2) shows 2D layers composed of [Cu2I2]infinity "stair step" chains which are cross-linked by Quin ligands. A total of 16 complexes of CuXL (L = P(OPh)3) with bridging ligand (B = those above and 1,4-dimethylpiperazine (DMP)) have also been prepared. All of these products, except those of HMTA, are of type 3 formulation, [(CuXL)2B]. The HMTA products have the formula [CuX(HMTA)], type 4. Thermal decomposition of the type 3 and 4 complexes occurs with initial loss of B, L, or both. The X-ray structures of [(CuBrL)2(Bpy)] and [(CuBrL)2(Pyz)] (type 3) reveal 1D chains formed from rhomboidal (LCu)2Br2 units linked by the B ligand. The type 4 structure of [CuBrL(HMTA)] is shown by X-ray to be a simple halide-bridged dimer.

Photopenic bone scan osteomyelitis: a clinical perspective.

Eighty-one pediatric patients had nuclear bone-imaging studies confirmatory of osteomyelitis during the past 10 years. Seven (8.6%) of 81 had "cold" osteomyelitis. These seven patients were all toxic [mean temperature (T), 39.9 degrees C; heart rate (HR), 145 beats/min], all had markedly elevated erythrocyte sedimentation rates (mean ESR, 76 mm/h), and six of seven had both confirmatory bone and blood cultures. All patients required surgical intervention. The average length of hospital stay for these seven patients was 32 days (range, 8-65 days). A control group of matched patients with "hot" osteomyelitis was constructed for statistical evaluation. This analysis confirmed significantly increased temperature, resting pulse rate, ESR, length of hospital stay, and rate of surgical intervention in patients with cold versus hot osteomyelitis. Patients with osteomyelitis presenting as a cold defect on bone imaging appeared to have a more aggressive type of bone infection, often requiring aggressive medical and surgical intervention adequately to control this infectious process.