984 resultados para RARE EARTHS COMPLEXES
Resumo:
Two new macropolycyclic hexaamines L(2) and L(4) as their copper(II) complexes have been isolated as products from the condensation of the diamino-substituted macrocyclic complex trans-(6,13-dimethyl-1,4,8,11-tetraazacyclo-tetradecane-6,13-diamine)copper(II) [CuL(1)](2+) with aqueous formaldehyde. Both of the complexes exhibit methylene bridges between the pendant amine and the adjacent co-ordinated macrocyclic N-donors. Their crystal structures have been determined: [CuL(2)(NCS)][SCN], triclinic, space group P (1) over bar, a = 7.133(2), b = 9.813(2), c = 16.745(3) Angstrom, alpha = 101.05(2), beta = 99.36(2), gamma = 99.77(2)degrees, Z = 2; [CuL(4)Cl][ClO4]. H2O, triclinic, space group P (1) over bar, a = 9.3327(8), b = 10.8989(6), c = 12.672(1) Angstrom, alpha = 68.591(6), beta = 78.899(6), gamma = 87.384(6)degrees, Z = 2. The complexes exhibit square-pyramidal geometries, and significantly lower-energy electronic maxima relative to their parent complex [CuL(1)](2+). Electrochemistry of [CuL(2)](2+) revealed a reversible Cu-II-Cu-I redox couple, by contrast to those of macromonocyclic analogues.
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Mixed connective tissue disease (MCTD) is a rare disease that includes clinical and laboratorial manifestations of systemic lupus erythematosus, scleroderma and polymyositis that is associated with high titers of anti-U1RNP antibodies. In general, muscle involvement is subclinical, usually appearing as an increase in muscle enzyme levels that tends to be a characteristic of the initial phases of the disease. Severe clinical muscle weakness is not observed in this disease. The objective of this study is to report a rare case of a patient who presented a severe onset of myositis characterized by dysphagia, an increase in myopathy and a weakening of the cervical musculature. While there was no response to the administration of an initial dose of corticosteroids, improvement was observed after increasing the dose of corticosteroids, in addition to the initiation of pulse therapy with methylprednisolone accompanied by methotrexate treatment. The authors emphasize that there is only one previously reported case regarding a child with MCTD and severe clinical myopathy on electromyography and muscle biopsy, and they report in this article one adult female patient who presented severe myositis and was refractive to corticotherapy. Lupus (2010) 19, 1659-1661.
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Introduction: Number 3 cleft or oral-nasal-ocular cleft is a well-known entity that was described by Morian over a century ago. This malformation is a paranasal-medial orbitomaxillary cleft running across the lacrimal segment of the lower eyelid and over the lacrimal groove. The Tessier number 3 naso-ocular cleft represents one of the most difficult and challenging malformations to correct for the reconstructive surgeon. We have conducted a retrospective analysis of our series consisting of 21 cases. Objective: The objective was to review the functional outcome and aesthetic results of the different techniques applied for each case. Materials and Methods: From 1997 to 2007, 21 patients with a Tessier number 3 cleft were treated in our craniofacial units. The clinical findings, tomographic studies, and surgical procedures were reviewed and analyzed. We have discussed our protocol of the treatment. Results: We have treated facial malformation in 2 craniofacial centers. Fourteen patients were evaluated in the first year of their life, with an average age at presentation of 3 years. Twelve patients were female, and 9 were male; 6 patients had amniotic bands in limbs, 5 patients had an association with Tessier number 11 cleft, 3 patients with number 9 cleft, and 1 with number 7 cleft. Related to cleft lip, 10 patients had bilateral cleft lip, and 8 patients had unilateral cleft lip. Three patients did not have any involvement of the upper lip. The alar base was deviated upward in 19 patients, 11 cases had severe anatomic alteration with the lateral border of the ala above the medial canthus, and 8 cases had a mild dislocation. Nine cases of lacrimal duct obstruction and 8 cases of lacrimal duct extrophy were identified. Twelve patients had a lower eyelid coloboma of varying grades, and there were 2 cases of microblepharia. Aiming the soft tissue reconstruction, eyelid, nose, and upper lip were evaluated regarding their position, absence of tissue, and position of medial canthus and ala. Twelve of our patients underwent correction in the same moment, their medial canthus rotated upward and the ala downward, using the contralateral side as the reference. The lip was treated using a Millard-like technique. Neo-conjunctivorhinostomy was performed in the same moment in 2 patients or later in 1 case. Four patients had plagiocephaly due to the cranial involvement, and they were submitted to cranioplasty. Three had neurosurgical approach and advancement of the frontal bandeau. One adult patient received an acrylic plate to reshape the frontal area. Conclusions: Tessier number 3 cleft is one of the most difficult and challenging malformations to correct for the reconstructive surgeon. Besides the difficulties of its treatment, patients with Tessier number 3 cleft may achieve good results when the team has good skills.
Resumo:
A number of N- and C-based diastereomeric copper(II) complexes of the pendant-arm macrocyclic hexaamines trans- and cis-6,13-dimethyl-1,4,8,11-tetraazacyclotetradecane-6,13-diamine (L-1 and L-2) have been isolated and characterised. The crystal structures of the complexes RRSS-[CuL1(OH2)(2)][ClO4](2), SSRR-[Cu(H2L1)(OClO3)(2)]-[ClO4](2) . 2H(2)O RSRS-[CuL1(OClO3)]ClO4, RSRS-[CuL2(OClO3)]ClO4 and RRSS-[Cu(H2L2)(OClO3)(2)][ClO4](2) have been determined. Some unusual structural and spectroscopic variations are found across this series of diastereomers. The protonation constants of the pendant primary amines are dependent on the relative dispositions of the adjacent macrocyclic secondary amine H atoms, which is indicative of intramolecular hydrogen-bonding interactions.
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The syntheses and characterisation of the new macrocyclic hexaamine trans-(5(S),7(S),12(R),14(R)-tetramethyl)-1,4,8,11-tetraazacyclotetradecane-6,13-diamine (L-6) and its Co-III complex are reported. The X-ray crystal structural analyses of [CoL6]Cl-2(ClO4) [monoclinic, space group C2/c, a = 16.468(3) Angstrom, b = 9.7156(7) Angstrom, c = 15.070(3) Angstrom, beta = 119.431(8)degrees, Z = 4] and the closely related cis-diamino-substituted macrocyclic complex [CoL2](ClO4)(3) . 2H(2)O (L-2 = cis-6,13-dimethyl-1,4,8,11-tetraazacyclotetradecane-6,13-diamine) [orthorhombic, space group Pna2(1), a = 16.8220(8) Angstrom, b = 10.416(2) Angstrom, c = 14.219(3) Angstrom, Z = 4] reveal significant variations in the observed Co-N bond lengths and coordination geometries, which may be attributed to the trans or cis disposition of the pendent primary amines. The Co-III/II self-exchange electron transfer rate constants for these and other closely related hexaamines have been determined, and variations of some 2 orders of magnitude are found between pairs of trans and cis isomeric Co-III complexes.
Resumo:
Three carbohydrate conjugated dipicolylamine chelators, 2-bis(2-pyridinylmethyl)amino)ethyl 1-deoxy-1-thio-beta-D-glucopyranoside (L(1)), 2-bis(2-pyridinylmethyl)amino)ethyl-beta-D-glucopyranoside (L(2)), and 2-bis(2-pyridinylmethyl)amino)carboxamide-N-(2-amino-2-deoxy-D-glucopyranose) (L(3)) were complexed to the [M(Co)(3)](+) core (M=Tc, Re) and the properties of the resulting complexes were investigated. Synthesis and characterization of the chelator 2-bis(2-pyridinylmethyl)amino)ethyl 1-deoxy-1-thio-beta-D-glucopyranoside (L(1)) and the corresponding Re complex are reported. All chelators were radiolabeled in high yield with [(99)mTc(CO)(3)(H(2)O)(3)](+) ( > 98%) and [(186)Re(CO)(3)(H(2)O)(3)](+) ( > 80%). The chelators and Re-complexes were determined to not be substrates for the glucose metabolism enzyme hexokinase. However, the biodistribution of each of the (99m)Tc complexes demonstrated fast clearance from most background tissue, including >75% clearance of the activity in the kidneys and the liver within 2 h post-injection. (C) 2010 Elsevier Ltd. All rights reserved.
Resumo:
A study of spin-orbit mixing and nephelauxetic effects in the electronic spectra of nickel(II)-encapsulating complexes involving mixed nitrogen and sulfur donors is reported. As the number of sulfur donors is systematically varied through the series [Ni(N6-xSx)](2+) (x = 0-6), the spin-forbidden (3)A(2)g --> E-1(g) and (3)A(2g) --> (1)A(1g) transitions undergo a considerable reduction in energy whereas the spin-allowed transitions are relatively unchanged. The [Ni(diAMN(6)sar)](2+) and [Ni(AMN(5)Ssar)](2+) complexes exhibit an unusual band shape for the (3)A(2g) --> T-3(2g) transition which is shown to arise from spin-orbit mixing of the E spin-orbit levels associated with the E-1(g) and T-3(2g) states. A significant differential nephelauxetic effect also arises from the covalency differences between the t(2g) and e(g) orbitals with the result that no single set of Racah B and C interelectron repulsion parameters adequately fit the observed spectra. Using a differential covalency ligand-field model, the spectral transitions are successfully reproduced with three independent variables corresponding to 10Dq and the covalency parameters f(t) and f(e), associated with the t(2g) and e(g) orbitals, respectively. The small decrease in f(t) from unity is largely attributed to central-field covalency effects whereas the dramatic reduction in f(e) with increasing number of sulfur donors is a direct consequence of the increased metal-ligand covalency associated with the sulfur donors. Covalency differences between the t(2g) and e(g) orbitals also result in larger 10Dq values than those obtained simply from the energy of the (3)A(2g) --> T-3(2g) spin-allowed transition.
Resumo:
Molybdenum hexacarbonyl reacted with the pendant-arm macrocycles 10-methyl-1,4,8, 12-tetraazacyclopentadecane-10-amine (L-1) and trans-6,13-dimethyl-1,4,8,11-tetraazacyclotetradecane-6, 13-diamine (L-2) in the absence of air to form complexes fac-[MoL1(CO)(3)] and [Mo2L2(CO)(8)] respectively. The mononuclear complex has the macrocycle bound in a tridentate manner, including the pendant primary amine, whereas the dinuclear complex exhibits a bridging bis(didentate) co-ordination mode, again involving the pendant primary amines. Structures have been defined by crystal structure analyses. The preferential binding of the pendant primary amines rather than additional secondary amines parallels similar behaviour observed earlier with some mercury(II) and rhodium(III) complexes, and points to the important general role of this pendant, despite being fused directly to the macrocyclic ring, in metal-ion binding.
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We describe in this paper the phenotype-genotype analysis of a Brazilian cohort of patients with cryopyrin-associated periodic syndromes (CAPS). Patient 1 presented with an urticarial rash and recurrent fever exacerbated by cold weather, arthritis, and anterior uveitis, thus, receiving a clinical diagnosis of familial cold autoinflammatory syndrome. CIAS1 sequencing identified the T436I mutation, previously associated to a clinical phenotype of chronic infantile neurological cutaneous and articular/neonatal onset multisystem inflammatory disease. Patient 2 developed a papular exanthema with daily fever shortly after birth, frontal bossing, patellae enlargement, and cognitive and motor impairments. Sequencing identified the exceedingly rare G755R CIAS1 mutation in exon 4. Patient 3 developed skin rash and articular symptoms 6 h after birth, followed by aseptic meningitis. He was found to have the novel C148Y missense mutation in CIAS1. This report expands the spectrum of CIAS1 mutations associated to clinical disease, suggests that the same mutation can be associated with different clinical syndromes, and supports the evidence that CAPS patients should always be screened for mutations outside exon 3.
Resumo:
PRES is a neuroclinical and radiological syndrome that results from treatment with calcineurin inhibitor immunosuppressives. Severe hypertension is commonly present, but some patients may be normotensive. We report herein two children who received liver transplants, as treatment for biliary atresia in the first case and for Alagille`s syndrome in the second one. In the early postoperative, both patients presented hypertension and seizures. In both cases, the image findings suggested the diagnosis of PRES. The CT scan showed alterations in the posterior area of the brain, and brain MRI demonstrated parietal and occipital areas of high signal intensity. Both children were treated by switching the immunosuppressive regimen and controlling arterial blood pressure. They displayed full recuperation without any neurologic sequelae. Probably, the pathophysiology of PRES results from sparse sympathetic innervation of the vertebrobasilar circulation, which is responsible for supplying blood to the posterior areas of the brain. In conclusion, all liver-transplanted children who present with neurological symptoms PRES should be considered in the differential diagnosis, although this is a rare complication. As treatment, we recommend rigorous control of arterial blood pressure and switching the immunosuppressive regimen.
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Alagille syndrome is a rare developmental disorder combining bile duct paucity, congenital cardiopathy, facial dysmorphy, vertebrae defects, and ocular abnormalities; and frequent renal abnormalities. It does not usually predispose to malignancies. Nephroblastoma has been observed in many developmental disorders, but never in Alagille syndrome. We report two original cases of nephroblastoma associated to Alagille syndrome. We identified a new V136G JAG1 missense mutation in one patient and a constitutional deletion of 20p12 in the other. In one nephroblastoma an additional somatic 1p36 deletion was present. The link between Alagille syndrome, JAG1 alterations and nephroblastoma is discussed.
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Sellar masses are associated most commonly with pituitary adenomas. Many other neoplastic, inflammatory, infectious, and vascular lesions, however, may affect the sellar region and mimic pituitary tumors. These lesions must be considered in a differential diagnosis. This article describes the characteristics of rare sellar masses that provide clues to their differential diagnosis.
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The complexes trans-[Ru(NO)(NH(3))(4)L](X)(3) (X = BF(4)(-), PF(6)(-) or Cl(-) and L = N-heterocyclic ligands, P (OEt)(3), SO(3)(-2)), and [Ru(NO)Hedta)] were shown to exhibit IC(50pro) in the range of 36 (L = imN) to 5000 mu M (L = imC). The inhibitory effects of trans-[Ru(NO)(NH(3))(4)imN](BF(4))(3) and of the Angeli`s salt on the growth of the intramacrophage amastigote form studied were found to be similar while the trans-[Ru(NH(3))(4)imN(H(2)O)](2+) complex was found not to exhibit any substantial antiamastigote effect. The trans-[Ru(NO)(NH(3))(4)imN](BF(4))(3) compound, administered (500 nmol kg(-1) day(-1)) in BALB/c mice infected with Leishmania major, was found to exhibit a 98% inhibition on the parasite growth. Furthermore, this complex proved to be at least 66 times more efficient than glucantime in in vivo experiments. (C) 2010 Elsevier Masson SAS. All rights reserved.