The influence of cis/trans isomerism on the physical properties of a cyano-bridged dinuclear mixed valence complex

The cyano-bridged complexes cis-[L14CoIIINCFeII(CN)5]– and cis-[L14CoIIINCFeIII(CN)5] (L14= 6-methyl-1,4,8,11-tetraazacyclotetradecan-6-amine) are prepared and characterised spectroscopically, electrochemically and structurally: Na{cis-[L14CoIIINCFeII(CN)5]}·9H2O, monoclinic space group P21/c, a= 14.758(3), b= 10.496(1), c= 19.359(3) , = 92.00(2)°, Z= 4; cis-[L14CoIIINCFeIII(CN)5]·4H2O, orthorhombic space group P212121, a= 9.492(1), b= 14.709(2), c= 18.760(3) , Z= 4. In both complexes, the pendant amine is cis to the bridging cyanide ligand. An analysis of the metal-to-metal charge transfer (MMCT) transition in these systems with Hush theory has been carried out. This has revealed that the change in the configuration of the macrocycle both decreases the redox isomer energy difference (E1/2) and increases the reorganisational energy () of the cis-[L14CoIIINCFeII(CN)5]– complex with respect to the trans-[L14CoIIINCFeII(CN)5]– complex, the result being that both isomers display an MMCT transition of similar energy. The variation in redox isomer energy differences of the configurational isomers has been related to strain energy differences by molecular mechanics analysis of the [CoL14Cl]2+/+ precursor complexes.

Outcomes after trans-tibial amputation: The relationship between quiet stance ability, strength of the hip abductor muscles and gait

Background and Purpose Previous research regarding the symmetry of trans-tibial amputees has examined weight distribution and various gait parameters between prosthetic and sound limbs. However, to date, no known research has determined if asymmetry is present in the strength of the hip abductor muscles or if correlations exist between these categories of symmetry. The purpose of the present study was, therefore, to document asymmetry present in stance, strength and gait measures, and to determine the relationship between these variables. Method Twenty-three elderly, unilateral trans-tibial amputees stood on two adjacent forceplates whilst the weight distribution and standard deviation (SD) of the anterior-posterior and the medio-lateral centre of pressure excursion (COPE) under each limb was recorded during four 40 s trials: quiet stance (QS), with eyes open and eyes closed; and even stance (ES), with eyes open and eyes closed. Gait measures (velocity, cadence, step and stride lengths, stance:swing ratio and period of double support) over 10 m of fast, yet safe walking and measures of the strength of hip abductor muscles were also obtained by use of a stride analyser and a dynamometer, respectively. Results No significant differences were found between QS and ES measures. However, significantly more weight was taken on the sound limb than on the amputated limb. Notably, more anterior-posterior movement occurred under the sound limb than the amputated limb, with this becoming more apparent with the eyes closed. Movement in the medio-lateral direction was found to be the same between sides. No differences in muscle strength or gait measures between limbs were demonstrated. However. strong hip abductor muscles were correlated with increased weight-bearing on the amputated limb, improved gait parameters and reduced medio-lateral COPE under the amputated limb. Conclusions This research confirms the asymmetrical nature of amputee stance and demonstrates symmetry of strength and gait measures between limbs. The correlations between hip abductor muscle strength, weight distribution and gait measures illustrates the importance of pre- and postoperative training of these muscles. Copyright © 2002 Whurr Publishers Ltd.

Solution Structures of the cis- and trans-Pro30 Isomers of a Novel 38-Residue Toxin from the Venom of Hadronyche Infensa sp. that Contains a Cystine-Knot Motif within Its Four Disulfide Bonds

The primary sequence and three-dimensional structure of a novel peptide toxin isolated from the Australian funnel-web spider Hadronyche infensa sp. is reported. ACTX-HI:OB4219 contains 38 amino acids, including eight-cysteine residues that form four disulfide bonds. The connectivities of these disulfide bonds were previously unknown but have been unambiguously determined in this study. Three of these disulfide bonds are arranged in an inhibitor cystine-knot (ICK) motif, which is observed in a range of other disulfide-rich peptide toxins. The motif incorporates an embedded ring in the structure formed by two of the disulfides and their connecting backbone segments penetrated by a third disulfide bond. Using NMR spectroscopy, we determined that despite the isolation of a single native homologous product by RP-HPLC, ACTX-HI:OB4219 possesses two equally populated conformers in solution. These two conformers were determined to arise from cis/trans isomerization of the bond preceding Pro30. Full assignment of the NMR spectra for both conformers allowed for the calculation of their structures, revealing, the presence of a triple-stranded antiparallel sheet consistent with the inhibitor cystine-knot (ICK) motif.

GLUT4 recycles via a trans-Golgi network (TGN) subdomain enriched in Syntaxins 6 and 16 but not TGN38: Involvement of an acidic targeting motif

Insulin stimulates glucose transport in fat and muscle cells by triggering exocytosis of the glucose transporter GLUT4. To define the intracellular trafficking of GLUT4, we have studied the internalization of an epitope-tagged version of GLUT4 from the cell surface. GLUT4 rapidly traversed the endosomal system en route to a perinuclear location. This perinuclear GLUT4 compartment did not colocalize with endosomal markers (endosomal antigen I protein, transferrin) or TGN38, but showed significant overlap with the TGN target (t)-soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) Syntaxins 6 and 16. These results were confirmed by vesicle immunoisolation. Consistent with a role for Syntaxins 6 and 16 in GLUT4 trafficking we found that their expression was up-regulated significantly during adipocyte differentiation and insulin stimulated their movement to the cell surface. GLUT4 trafficking between endosomes and trans-Golgi network was regulated via an acidic targeting motif in the carboxy terminus of GLUT4, because a mutant lacking this motif was retained in endosomes. We conclude that GLUT4 is rapidly transported from the cell surface to a subdomain of the trans-Golgi network that is enriched in the t-SNAREs Syntaxins 6 and 16 and that an acidic targeting motif in the C-terminal tail of GLUT4 plays an important role in this process.

The trans-membrane protein p25 forms highly specialized domains that regulate membrane composition and dynamics

Trans-membrane proteins of the p24 family are abundant, oligomeric proteins predominantly found in cis-Golgi membranes. They are not easily studied in vivo and their functions are controversial. We found that p25 can be targeted to the plasma membrane after inactivation of its canonical KKXX motif (KK to SS, p25SS), and that p25SS causes the co-transport of other p24 proteins beyond the Golgi complex, indicating that wild-type p25 plays a crucial role in retaining p24 proteins in cis-Golgi membranes. We then made use of these observations to study the intrinsic properties of these proteins, when present in a different membrane context. At the cell surface, the p25SS mutant segregates away from both the transferrin receptor and markers of lipid rafts, which are enriched in cholesterol and glycosphingolipids. This suggests that p25SS localizes to, or contributes to form, specialized membrane domains, presumably corresponding to oligomers of p25SS and other p24 proteins. Once at the cell surface, p25SS is endocytosed, together with other p24 proteins, and eventually accumulates in late endosomes, where it remains confined to well-defined membrane regions visible by electron microscopy. We find that this p25SS accumulation causes a concomitant accumulation of cholesterol in late endosomes, and an inhibition of their motility - two processes that are functionally linked. Yet, the p25SS-rich regions themselves seem to-exclude not only Lamp1 but also accumulated cholesterol. One may envision that p25SS accumulation, by excluding cholesterol from oligomers, eventually overloads neighboring late endosomal membranes with cholesterol beyond their capacity (see Discussion). In any case, our data show that p25 and presumably other p24 proteins are endowed with the intrinsic capacity to form highly specialized domains that control membrane composition and dynamics. We propose that p25 and other p24 proteins control the fidelity of membrane transport by maintaining cholesterol-poor membranes in the Golgi complex.

GRIP domain-mediated targeting of two new coiled-coil proteins, GCC88 and GCC185, to subcompartments of the trans-Golgi network

The GRIP domain is a targeting sequence found in a family of coiled-coil peripheral Golgi proteins. Previously we demonstrated that the GRIP domain of p230/golgin245 is specifically recruited to tubulovesicular structures of the traps-Golgi network (TGN). Here we have characterized two novel Golgi proteins with functional GRIP domains, designated GCC88 and GCC185. GCC88 cDNA encodes a protein of 88 kDa, and GCC185 cDNA encodes a protein of 185 kDa. Both molecules are brefeldin A-sensitive peripheral membrane proteins and are predicted to have extensive coiled-coil regions with the GRIP domain at the C terminus. By immunofluorescence and immunoelectron microscopy GCC88 and GCC185, and the GRIP protein golgin97, are all localized to the TGN of Hela cells. Overexpression of full-length GCC88 leads to the formation of large electron dense structures that extend from the traps-Golgi. These de novo structures contain GCC88 and co-stain for the TGN markers syntaxin 6 and TGN38 but not for alpha2,6-sialyltransferase, beta-COP, or cis-Golgi GM130. The formation of these abnormal structures requires the N-terminal domain of GCC88. TGN38, which recycles between the TGN and plasma membrane, was transported into and out of the GCC88 decorated structures. These data introduce two new GRIP domain proteins and implicate a role for GCC88 in the organization of a specific TGN subcompartment involved with membrane transport.

GAIP participates in budding of membrane carriers at the trans-Golgi network

Galpha interacting protein (GAIP) is a regulator of G protein signaling protein that associates dynamically with vesicles and has been implicated in membrane trafficking, although its specific role is not yet known. Using an in vitro budding assay, we show that GAIP is recruited to a specific population of trans-Golgi network-derived vesicles and that these are distinct from coatomer or clathrin-coated vesicles. A truncation mutant (NT-GAIP) encoding only the N-terminal half of GAIP is recruited to trans -Golgi network membranes during the formation of vesicle carriers. Overexpression of NT-GAIP induces the formation of long, coated tubules, which are stabilized by microtubules. Results from the budding assay and from imaging in live cells show that these tubules remain attached to the Golgi stack rather than being released as carrier vesicles. NT-GAIP expression blocks membrane budding and results in the accumulation of tubular carrier intermediates. NT-GAIP-decorated tubules are competent to load vesicular stomatitis virus protein G-green fluorescent protein as post-Golgi, exocytic cargo and in cells expressing NT-GAIP there is reduced surface delivery of vesicular stomatitis virus protein G-green fluorescent protein. We conclude that GAIP functions as an essential part of the membrane budding machinery for a subset of post-Golgi exocytic carriers derived from the trans-Golgi network.

The AF-1 Domain of the Orphan Nuclear Receptor NOR-1 Mediates Trans-activation, Coactivator Recruitment, and Activation by the Purine Anti-metabolite 6-Mercaptopurine

NOR-1/NR4A3 is an orphan member of the nuclear hormone receptor superfamily. NOR-1 and its close relatives Nurr1 and Nur77 are members of the NR4A subgroup of nuclear receptors. Members of the NR4A subgroup are induced through multiple signal transduction pathways. They have been implicated in cell proliferation, differentiation, T-cell apoptosis, chondrosarcomas, neurological disorders, inflammation, and atherogenesis. However, the mechanism of transcriptional activation, coactivator recruitment, and agonist-mediated activation remain obscure. Hence, we examined the molecular basis of NOR-1-mediated activation. We observed that NOR-1 trans-activates gene expression in a cell- and target-specific manner; moreover, it operates in an activation function (AF)-1-dependent manner. The N-terminal AF-1 domain delimited to between amino acids 1 and 112, preferentially recruits the steroid receptor coactivator (SRC). Furthermore, SRC-2 modulates the activity of the AF-1 domain but not the C-terminal ligand binding domain (LBD). Homology modeling indicated that the NOR-1 LBD was substantially different from that of hRORbeta, a closely related AF-2-dependent receptor. In particular, the hydrophobic cleft characteristic of nuclear receptors was replaced with a very hydrophilic surface with a distinct topology. This observation may account for the inability of this nuclear receptor LBD to efficiently mediate cofactor recruitment and transcriptional activation. In contrast, the N-terminal AF-1 is necessary for cofactor recruitment and can independently conscript coactivators. Finally, we demonstrate that the purine anti-metabolite 6-mercaptopurine, a widely used antineoplastic and anti-inflammatory drug, activates NOR-1 in an AF-1-dependent manner. Additional 6-mercaptopurine analogs all efficiently activated NOR-1, suggesting that the signaling pathways that modulate proliferation via inhibition of de novo purine and/or nucleic acid biosynthesis are involved in the regulation NR4A activity. We hypothesize that the NR4A subgroup mediates the genotoxic stress response and suggest that this subgroup may function as sensors that respond to genotoxicity.

Laringectomia frontal anterior: técnica de Tucker. Estudo retrospectivo

O carcinoma epidermóide da laringe é a sexta neoplasia mais comum, sendo uma das neoplasias malignas mais freqüentes na cabeça e pescoço, ocupando o segundo lugar imediatamente após o câncer da cavidade oral. FORMA DE ESTUDO: Estudo clínico retrospectivo. MATERIAL E MÉTODO: Entre os anos de 1991 e 2003, 24 pacientes portadores de lesões glóticas envolvendo a comissura anterior foram submetidos a laringectomia frontal anterior com epiglotoplastia descrita por Tucker e colaboradores no ano de 1979. RESULTADO: Nossos resultados confirmam aqueles encontrados em outras publicações. Não ocorreram mortes no pós-operatório e o seguimento foi relativamente simples. Todos os pacientes foram decanulizados e recuperaram um efetivo trato digestivo e aéreo. CONCLUSÃO: Nossos achados mostram que a laringectomia pela técnica de Tucker é uma cirurgia efetiva para o tratamento dos carcinomas glóticos que acometem a comissura anterior e a porção membranosa das cordas vocais com a motilidade preservada, pois tais lesões não devem ser tratadas pela ressecção endoscópica trans-oral ou por uma laringectomia fronto lateral.

Estudo comparativo entre duas técnicas de tonsilectomia: bisturi harmônico (Ultracision) e dissecção tradicional com bisturi de lâmina fria

Tonsilectomia é a cirurgia realizada com maior frequência na clínica otorrinolaringológica. As modificações e as evoluções da técnica ocorrem no sentido de simplificar o procedimento e minimizar as complicações. O bisturi harmônico (Ultracision) começou a ser utilizado na Otorrinolaringologia em 1999 para tonsilectomia com bons resultados. OBJETIVO: O objetivo deste estudo foi comparar o tempo cirúrgico, sangramento e hemostasia trans-operatórios, dor pós-operatória, aspecto cicatricial da loja tonsilar e intercorrências no trans e pós-operatório em pacientes submetidos a tonsilectomia pela técnica tradicional com lâmina fria e pela técnica utilizando lâmina cirúrgica em ganchos de coagulação Ultracision. FORMA DE ESTUDO: Coorte transversal. CASUÍSTICA E MÉTODO: Vinte e seis pacientes foram submetidos a tonsilectomia: 13 pela técnica tradicional com bisturi de lâmina fria e 13 pela técnica com Ultracision, avaliando os parâmetros previamente estabelecidos através de um protocolo padrão. Os pacientes foram submetidos a uma análise da intensidade da dor através da escala analógica visual horizontal. RESULTADOS: O tempo cirúrgico foi estatisticamente menor na cirurgia realizada pela técnica com o bisturi harmônico comparada com a técnica tradicional. O percentual de pontos dados na loja tonsilar também mostrou-se mais baixo do que pela técnica tradicional. Não houve diferença significativa em relação ao padrão de dor e a evolução pós-operatória do aspecto cicatricial da loja. CONCLUSÃO: O bisturi harmônico mostrou ser um excelente recurso para a realização de cirurgias onde o tempo cirúrgico e o sangramento trans-operatório são de grande importância.

Acesso transmaxilar à base do crânio: avaliação de 11 casos

O acesso cirúrgico à região de base do crânio é sempre difícil principalmente pelas estruturas anatômicas nobres associadas. A osteotomia maxilar proporciona visão direta à região de clivus e coluna cervical, além de apresentar uma menor morbidade em relação aos diversos acessos descritos na literatura. OBJETIVO: Avaliar 11 casos submetidos à osteotomia transmaxilar, descrevendo técnica cirúrgica, resultados e complicações pós-operatórias. PACIENTES E MÉTODOS: O estudo retrospectivo de onze pacientes foi submetido à cirurgia transmaxilar para acesso à região do tronco encefálico. Registros quanto à oclusão dentária, hemorragia trans e pós-operatória, necrose óssea e alterações de tecido mole foram estudados. Todos seguiram o mesmo protocolo cirúrgico e acompanhamento médio de dois anos. RESULTADOS: Após o tratamento todos os pacientes apresentaram melhora do quadro clínico e nenhum dano neurológico, hemorragia trans e pós-operatória ou intercorrências maiores foram identificadas. Dentre as complicações, em dois pacientes ocorreu fratura incompleta da maxila, dois apresentaram laceração da mucosa nasal e um apresentou como complicação tardia uma fístula bucossinusal. CONCLUSÃO: A osteotomia transmaxilar possibilitou adequado acesso a região de clivus para descompressão do tronco encefálico com baixo índice de complicações nesta série de casos.

Determinação de resveratrol e características químicas em sucos de uvas produzidas em sistemas orgânico e convencional

O presente estudo avaliou os teores de trans-resveratrol e algumas características químicas: acidez total titulável (ATT), sólidos solúveis totais (SST) e relação SST/ATT, em amostras de sucos de uvas da variedade Concorde e Rúbea, sobre o porta-enxerto Campinas IAC 766, produzidas em sistemas orgânico e convencional. O suco foi obtido pelo método de cocção de uvas sadias e maduras. Os resultados encontrados para os sucos de uvas das variedades Concorde e Rúbea, sobre o porta-enxerto Campinas IAC 766, orgânico e convencional, apresentaram concentração de trans-resveratrol de 25,9; 27,2; 32,5 e 32,9 mg L-1, respectivamente. No suco das variedades Concorde e Rúbea de produção orgânica foram obtidos os valores de 0,77 e 0,91 g de ácido tartárico 100 mL-1. Para as mesmas variedades produzidas em sistema convencional 0,94 e 0,75 g de ácido tartárico 100 mL-1. Os valores observados para SST e SST/ ATT para as variedades de sistemas orgânico e convencional foram 10,95; 11,73; 14,23; e 13,23 ºBrix e 14,22; 12,64; 15,18; e 17,64, respectivamente. Das avaliações realizadas com relação ao trans-resveratrol pode-se concluir que as variedades, independentemente do sistema de cultivo, são fontes de resveratrol e que os sucos podem ser consumidos como alimento funcional.

Dois motores do crescimento corporativo

Este artigo propõe a estrutura geral de dois motores atuantes em processos de crescimento da empresa. São eles: o de crescimento contínuo, que compreende um processo no qual crescimento produz mais crescimento, e o de co-evolução, que relaciona o crescimento concomitante de um todo e suas partes, a exemplo de uma indústria (todo) e suas firmas (partes). A concepção dos motores inspirou-se na obra de Chandler intitulada The visible hand (1977). O minucioso exame da obra segundo a perspectiva orientada a processo de Mohr (1982) buscou responder à questão "qual é a teoria de Chandler a respeito de como e por que a moderna empresa de negócios (MEN) surgiu e cresceu?". Quatro classes de processos - formação da MEN, desenvolvimento da MEN, formação da indústria e desenvolvimento da indústria - foram identificadas e descritas por meio de encadeamentos de relações de necessidade (baseadas em condições necessárias mas não suficientes). Embora tenham menor poder preditivo que as relações causais (baseadas em condições necessárias e suficientes), as relações de necessidade parecem melhor descrever a realidade complexa das relações envolvidas em processos organizacionais. Finalmente, o exame do crescimento da indústria de microcomputadores à luz dos motores de crescimento propostos fornece evidências de que estes são adequados para analisar indústrias modernas, sugerindo que os motores de crescimento contínuo e de co-evolução são potencialmente trans-históricos e oferecem contribuição para uma teoria geral e para a prática da gestão do crescimento corporativo.

Desafios para a coordenação intergovernamental do Programa Bolsa Família

O artigo aborda a coordenação intergovernamental tiva intersetorial que rege o Programa. Duas ordens do Programa Bolsa Família (PBF), dado seu objetivo de desafios são destacadas. A primeira relaciona-se de enfrentamento da pobreza em um país de profun-à necessidade de maior investimento em espaços e da desigualdade social e regional. Busca qualificar o oportunidades de negociação intergovernamental, debate sobre a centralização dos programas de trans-sobretudo na dimensão da transferência de renda, a ferência de renda no Brasil por meio da análise das qual inicialmente se caracterizou pela centralização. relações intergovernamentais adotadas no âmbito das Na segunda, a questão intergovernamental demanda três principais dimensões do PBF - transferência de a organização de uma estratégia nacional coorderenda, acompanhamento de condicionalidades e arti-nada de articulação de programas complementares, culação de programas complementares - consideran-sugerindo-se maior participação dos estados na codo-se as implicações federativas derivadas da perspec-ordenação regional do Programa.