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Unusual Example (unusual + example)

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Medical Sciences50%
Chemistry50%

Selected Abstracts

Marinesco-Sjögren syndrome with atrophy of the brain stem tegmentum and dysplastic cytoarchitecture in the cerebral cortex

NEUROPATHOLOGY, Issue 5 2008
Kenji Sakai
Marinesco-Sjögren syndrome (MSS) is a progressive multisystem disease with autosomal recessive inheritance characterized by cataracts, mental retardation, and cerebellar ataxia. Recently, two causative genes for MSS, SIL1 and SARA2, have been identified. On the other hand, the histopathologic features of the CNS in this syndrome have not yet been clarified in detail. We report here the features of an autopsy case of MSS with progressive myopathy, in which atrophy of the cerebellum and brain stem tegmentum, retinal degeneration, and dysplastic cytoarchitecture in the cerebral cortex were evident. An elder brother of the patient showed quite similar symptoms, implying an autosomal recessive mode of inheritance. However, we detected no mutations in the available genes. This case appears to represent an unusual example of MSS manifesting widespread developmental anomaly and neuronal degeneration in the CNS. [source]

A capped trigonal prismatic cadmium complex with tetra- and tridentate ligands: bis­(tri­ethanol­amine)-,3N,O,O,;,4N,O,O,,O,,-cadmium(II) squarate monohydrate

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 8 2004
brahim Uçar
In the crystal structure of the title compound, [Cd(C6H15NO3)2](C4O4)·H2O, a supramolecular structure is observed. The asymmetric unit consists of one unit of the cationic Cd complex, one water mol­ecule and two half-squarate anions, each sitting on a crystallographic inversion center. The different coordinations of the two triethanolamine (TEA) ligands results in an unusual example of coordination number seven for the CdII ion. Both TEA ligands coordinate to the CdII ion, forming a distorted monocapped trigonal prismatic geometry with approximate C2v symmetry. One of the TEA ligands acts as an N,O,O,-tridentate ligand, whereas the other behaves as an N,O,O,,O,,-tetradentate donor. The anions and cations are linked to one another by hydrogen bonds between hydroxy H atoms of the TEA ligands and squarate O atoms. The crystal structure is stabilized by O,H,O hydrogen bonds between the unligated water mol­ecule and a squarate O atom, together with a weak ,,ring interaction between the ethyl­ene group of a TEA ligand and a squarate anion. [source]

Diboryl and Diboranyl Porphyrin Complexes: Synthesis, Structural Motifs, and Redox Chemistry: Diborenyl Porphyrin or Diboranyl Isophlorin?

CHEMISTRY - A EUROPEAN JOURNAL, Issue 21 2007
Andre Weiss Dr.
Abstract The syntheses of diboryl porphyrin complexes [(BX2)2(ttp)] (ttp: dianion of tetra- p -tolylporphyrin) and the BB single-bond diboranyl complexes [(BX)2(ttp)] (X=F, Cl, Br, I) are given. The former are prepared from the reactions of BX3 (X=F, Cl) with [Li2(ttp)] and the latter from B2Cl4 (X=Cl), the reaction of SbF3 with [(BCl)2(ttp)] (for X=F), and, in the cases of X=Br or I, in a remarkable reductive coupling reaction resulting directly from the reaction of BBr3 or BI3 with [Li2(ttp)]. Density functional theory (DFT) calculations on the thermochemical parameters for the reductive coupling reactions (and those calculated for related dipyrromethene complexes) indicate that a combination of the reducing ability of bromide and iodide ions combined with the constrained environment of the porphyrin ligand contribute to the driving force. The reductive coupling is also observed in the reaction of [(BCl2)2(ttp)] with nBuLi to give [(BnBu)2(ttp)], which was characterised crystallographically. The reaction of [(BCl)2(ttp)] with catechol gives a boron catecholato porphyrin complex, [B2(O2C6H4)(ttp)]. Chloride abstraction from [(BCl)2(ttp)] gives the planar dication [B2(ttp)]2+, whereas chemical reduction of [(BCl)2(ttp)] by using magnesium anthracenide gives a neutral complex, [B2(ttp)], in which the TTP ligand has been reduced by two electrons to give an unusual example of an isophlorin complex. The cationic and neutral complexes [B2(ttp)]2+ and [B2(ttp)] were characterised through a combination of spectroscopic data that is supported by DFT calculations on the porphine analogues. [source]

Myopericytoma: report of two cases associated with trauma

JOURNAL OF CUTANEOUS PATHOLOGY, Issue 9 2008
Alvaro C. Laga
Myopericytoma is a rare, recently described tumor demonstrating a hemangiopericytoma-like vascular pattern. We present two cases of myopericytoma associated with trauma: a 64-year-old man who developed several nodules on his nose four months after sustaining multiple abrasions to his forehead and nose, and a 72-year-old woman with a solitary growth in the alveolar ridge of unknown duration. Biopsy specimens of the lesions in both cases demonstrated a striking concentric perivascular proliferation of bland spindle-shaped pericytic cells characteristic of myopericytoma. Despite sharing morphologic features with angioleiomyoma, myofibroma and glomus tumor, myopericytoma is thought to represent a distinct perivascular myoid neoplasm of skin and soft tissues. The tumor is characterized by a radial and perivascular arrangement of ovoid, spindled to round neoplastic cells that are immunoreactive to alpha-smooth muscle actin, often for h-caldesmon as well as smooth muscle myosin-heavy chain, and usually negative for desmin antibodies. Most cases of myopericytoma are benign, however, local recurrence and malignancy have recently been reported, Myopericytoma can be multifocal involving a single or multiple anatomic regions, and tends to occur in dermal and superficial soft tissues of adults primarily on the extremities. Our cases are unusual examples of myopericytoma manifesting as multiple nodules on the nose, and a solitary growth on the buccal mucosa after trauma. [source]