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1.
Neural Comput Appl ; 35(16): 11497-11516, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-35039718

RESUMO

This study investigated the application of a recurrent neural network for optimising pharmacological treatment for depression. A clinical dataset of 458 participants from specialist and community psychiatric services in Australia, New Zealand and Japan were extracted from an existing custom-built, web-based tool called Psynary . This data, which included baseline and self-completed reviews, was used to train and refine a novel algorithm which was a fully connected network feature extractor and long short-term memory algorithm was firstly trained in isolation and then integrated and annealed using slow learning rates due to the low dimensionality of the data. The accuracy of predicting depression remission before processing patient review data was 49.8%. After processing only 2 reviews, the accuracy was 76.5%. When considering a change in medication, the precision of changing medications was 97.4% and the recall was 71.4% . The medications with predicted best results were antipsychotics (88%) and selective serotonin reuptake inhibitors (87.9%). This is the first study that has created an all-in-one algorithm for optimising treatments for all subtypes of depression. Reducing treatment optimisation time for patients suffering with depression may lead to earlier remission and hence reduce the high levels of disability associated with the condition. Furthermore, in a setting where mental health conditions are increasing strain on mental health services, the utilisation of web-based tools for remote monitoring and machine/deep learning algorithms may assist clinicians in both specialist and primary care in extending specialist mental healthcare to a larger patient community.

2.
Chemistry ; 27(34): 8714-8722, 2021 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-33830552

RESUMO

The separation and isolation of many of the platinum group metals (PGMs) is currently achieved commercially using solvent extraction processes. The extraction of rhodium is problematic however, as a variety of complexes of the form [RhCln (H2 O)6-n ](n-3)- are found in hydrochloric acid, making it difficult to design a reagent that can extract all the rhodium. In this work, the synergistic combination of a primary amine (2-ethylhexylamine, LA ) with a primary amide (3,5,5-trimethylhexanamide, L1 ) is shown to extract over 85 % of rhodium from 4 M hydrochloric acid. Two rhodium complexes are shown to reside in the organic phase, the ion-pair [HLA ]3 [RhCl6 ] and the amide complex [HLA ]2 [RhCl5 (L1 )]; in the latter complex, the amide is tautomerized to its enol form and coordinated to the rhodium centre through the nitrogen atom. This insight highlights the need for ligands that target specific metal complexes in the aqueous phase and provides an efficient synergistic solution for the solvent extraction of rhodium.


Assuntos
Ródio , Amidas , Aminas , Ácido Clorídrico , Solventes
3.
Inorg Chem ; 58(13): 8720-8734, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-31247879

RESUMO

Current methods for the extraction of rhodium carry the highest carbon footprint and worst pollution metrics of all of the elements used in modern technological applications. Improving upon existing methods is made difficult by the limited understanding of the molecular-level chemistry occurring in extraction processes, particularly in the hydrometallurgical separation step. While many of the precious metals can be separated by solvent extraction, there currently exist no commercial extractants for Rh. This is due to its complicated mixed speciation upon leaching into hydrochloric acid, which gives rise to difficulties in designing effective reagents for solvent extraction. Herein we show that the diamidoamine reagent N- n-hexylbis( N-methyl- N- n-octylethylamide)amine transports Rh(III) from aqueous HCl into an organic phase as the monoaquated dianion [RhCl5(H2O)]2- through the formation of an outer-sphere assembly; this assembly has been characterized by experimentation (slope analysis, FT-IR and NMR spectroscopy, EXAFS, SANS, and ESI-MS) and computational modeling. The paper demonstrates the importance of applying a broad range of techniques to obtain a convincing mode of action for the complex processes involved in anion recognition in the solution phase. A consistent and comprehensive understanding of how the ligand operates to achieve Rh(III) selectivity over the competitor anion Cl- has emerged. This knowledge will guide the design of extractants and thus offers promise for improving the sustainability of metal extraction from both traditional mining sources and the recycling of secondary source materials.

4.
Exp Neurobiol ; 25(3): 103-12, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27358578

RESUMO

The subgranular zone (SGZ) and subventricular zone (SVZ) are developmental remnants of the germinal regions of the brain, hence they retain the ability to generate neuronal progenitor cells in adult life. Neurogenesis in adult brain has an adaptive function because newly produced neurons can integrate into and modify existing neuronal circuits. In contrast to the SGZ and SVZ, other brain regions have a lower capacity to produce new neurons, and this usually occurs via parenchymal and periventricular cell genesis. Compared to neurogenesis, gliogenesis occurs more prevalently in the adult mammalian brain. Under certain circumstances, interaction occurs between neurogenesis and gliogenesis, facilitating glial cells to transform into neuronal lineage. Therefore, modulating the balance between neurogenesis and gliogenesis may present a new perspective for neurorestoration, especially in diseases associated with altered neurogenesis and/or gliogenesis, cell loss, or disturbed homeostasis of cellular constitution. The present review discusses important neuroanatomical features of adult neurogenesis and gliogenesis, aiming to explore how these processes could be modulated toward functional repair of the adult brain.

5.
J Vis Exp ; (108): 53673, 2016 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-26967767

RESUMO

Long descending fibers to the spinal cord are essential for locomotion, pain perception, and other behaviors. The fiber termination pattern in the spinal cord of the majority of these fiber systems have not been thoroughly investigated in any species. Serotonergic fibers, which project to the spinal cord, have been studied in rats and opossums on histological sections and their functional significance has been deduced based on their fiber termination pattern in the spinal cord. With the development of CLARITY and CUBIC techniques, it is possible to investigate this fiber system and its distribution in the spinal cord, which is likely to reveal previously unknown features of serotonergic supraspinal pathways. Here, we provide a detailed protocol for imaging the serotonergic fibers in the mouse spinal cord using the combined CLARITY and CUBIC techniques. The method involves perfusion of a mouse with a hydrogel solution and clarification of the tissue with a combination of clearing reagents. Spinal cord tissue was cleared in just under two weeks, and the subsequent immunofluorescent staining against serotonin was completed in less than ten days. With a multi-photon fluorescent microscope, the tissue was scanned and a 3D image was reconstructed using Osirix software.


Assuntos
Neurônios Serotoninérgicos/metabolismo , Medula Espinal/anatomia & histologia , Animais , Camundongos , Microscopia de Fluorescência/métodos , Fibras Nervosas/metabolismo , Ratos , Serotonina/metabolismo , Medula Espinal/diagnóstico por imagem , Coloração e Rotulagem/métodos
6.
Br J Clin Pharmacol ; 78(2): 320-8, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25099258

RESUMO

AIMS: Aspirin is widely used as an anti-platelet agent for cardiovascular prophylaxis. Despite aspirin treatment, many patients experience recurrent thrombotic events, and aspirin resistance may contribute to this. We examined the prevalence of aspirin resistance in a healthy population, and investigated whether the platelet proteome differed in aspirin-resistant subjects. METHODS: Ninety-three healthy subjects received aspirin 300 mg daily for 28 days. Before and at the end of treatment, urine was taken to determine 11-dehydrothromboxane B2 , and blood was taken to measure arachidonic acid (AA)-induced aggregation of platelet-rich plasma and to interrogate the platelet proteome by mass spectrometric analysis with further confirmation of findings using Western blotting. RESULTS: In two of the 93 subjects, neither AA-induced aggregation nor urinary 11-dehydrothromboxane B2 was effectively suppressed by aspirin, despite measurable plasma salicylate concentrations, suggesting the presence of true aspirin resistance. Despite no detectable differences in the platelet proteome at baseline, following aspirin a marked increase was seen in platelet glycoprotein IIIa expression in the aspirin-resistant but not aspirin-sensitive subjects. An increase in platelet glycoprotein IIIa expression with aspirin resistance was confirmed in a separate cohort of 17 patients with stable coronary artery disease on long term aspirin treatment, four of whom exhibited aspirin resistance. CONCLUSIONS: In a healthy population, true aspirin resistance is uncommon but exists. Resistance is associated with an increase in platelet glycoprotein IIIa expression in response to aspirin. These data shed new light on the mechanism of aspirin resistance, and provide the potential to identify aspirin-resistant subjects using a novel biomarker.


Assuntos
Aspirina/farmacologia , Plaquetas/efeitos dos fármacos , Resistência a Medicamentos , Integrina beta3/biossíntese , Agregação Plaquetária/efeitos dos fármacos , Adulto , Ácido Araquidônico/farmacologia , Aspirina/administração & dosagem , Aspirina/sangue , Aspirina/urina , Plaquetas/citologia , Plaquetas/metabolismo , Estudos de Coortes , Doença da Artéria Coronariana/sangue , Doença da Artéria Coronariana/tratamento farmacológico , Relação Dose-Resposta a Droga , Feminino , Voluntários Saudáveis , Humanos , Masculino , Tromboxano B2/análogos & derivados , Tromboxano B2/urina
8.
J Mol Neurosci ; 47(1): 192-203, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22351109

RESUMO

The role of hyperphosphorylation of the microtubule-associated protein tau in the pathological processes of several neurodegenerative diseases is becoming better understood. Consequently, development of new compounds capable of preventing tau hyperphosphorylation is an increasingly hot topic. For this reason, dependable in vitro and in vivo models that reflect tau hyperphosphorylation in human diseases are needed. In this study, we generated and validated an in vitro model appropriate to test potential curative and preventive compound effects on tau phosphorylation. For this purpose, a stably transfected SH-SY5Y cell line was constructed over-expressing mutant human tau441 (SH-SY5Y-TMHT441). Analyses of expression levels and tau phosphorylation status in untreated cells confirmed relevance to human diseases. Subsequently, the effect of different established kinase inhibitors on tau phosphorylation (e.g., residues Thr231, Thr181, and Ser396) was examined. It was shown with several methods including immunosorbent assays and mass spectrometry that the phosphorylation pattern of tau in SH-SY5Y-TMHT441 cells can be reliably modulated by these compounds, specifically targeting JNK, GSK-3, CDK1/5, and CK1. These four protein kinases are known to be involved in in vivo tau phosphorylation and are therefore authentic indicators for the suitability of this new cell culture model for tauopathies.


Assuntos
Doença de Alzheimer/tratamento farmacológico , Doença de Alzheimer/genética , Testes Genéticos/métodos , Farmacogenética/métodos , Proteínas tau/genética , Doença de Alzheimer/patologia , Animais , Linhagem Celular Tumoral , Desenho de Fármacos , Humanos , Camundongos , Camundongos Transgênicos , Mutagênese/fisiologia , Neuroblastoma/tratamento farmacológico , Neuroblastoma/genética , Neuroblastoma/patologia , Fosforilação/efeitos dos fármacos , Fosforilação/genética , Tauopatias/tratamento farmacológico , Tauopatias/genética , Tauopatias/metabolismo , Transfecção/métodos
9.
J Neurol ; 259(3): 482-90, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21837549

RESUMO

In order to determine the relationship between regional neuropathology and severity of clinical features in Richardson's syndrome (PSP-RS), the following hypotheses were tested: (1) executive dysfunction relates to prefrontal pathology; (2) language difficulties to pathology in Broca's area and/or the perirhinal cortex; and (3) visuospatial impairment to pathology in the supramarginal region. A prospectively studied case series of brain donors at a specialist clinic in Addenbrooke's Hospital Cambridge, UK, were examined. All those fulfilling postmortem criteria for PSP-RS and their last cognitive assessment within 24 months of death (N = 11/25) were included. The degree of regional neuronal loss and neuronal tau deposition across a number of cortical brain regions was performed and compared to 10 age- and sex-matched controls from the Sydney Brain Bank. Stepwise multiple linear regressions were used to determine the neuropathological correlates to cognitive scores and revealed the following. Executive dysfunction, as indexed by letter fluency, related to the degree of tau deposition in the superior frontal gyrus and supramarginal cortices (p < 0.020), language deficits related to neuron loss in the perirhinal gyrus (p < 0.001) and tau deposition in Broca's area (p = 0.020), while visuospatial dysfunction and global cognitive impairment related to tau deposition in the supramarginal gyrus (p < 0.007). The severity of cognitive deficits relate to regional cortical tau deposition in PSP-RS, although language impairment related to neuronal loss in the perirhinal region. Global cognitive dysfunction related most to the severity of tau deposition in the supramarginal gyrus warranting further research on the role of this brain region in PSP-RS.


Assuntos
Transtorno do Deficit de Atenção com Hiperatividade/etiologia , Encéfalo/patologia , Transtornos Cognitivos/etiologia , Transtornos da Percepção/etiologia , Paralisia Supranuclear Progressiva/complicações , Paralisia Supranuclear Progressiva/patologia , Idoso , Encéfalo/metabolismo , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Neurônios/metabolismo , Neurônios/patologia , Testes Neuropsicológicos , Percepção Visual , Proteínas tau/metabolismo
10.
Mov Disord ; 26(2): 256-63, 2011 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-21412832

RESUMO

To determine whether brain atrophy differs between the two subtypes of progressive supranuclear palsy (PSP), Richardson's syndrome (PSP-RS), and PSP parkinsonism (PSP-P), and whether such atrophy directly relates to clinical deficits and the severity of tau deposition. We compared 24 pathologically confirmed PSP cases (17 PSP-RS and 7 PSP-P) with 22 controls from a Sydney brain donor program. Volume loss was analyzed in 29 anatomically discrete brain regions using a validated point-counting technique, and tau-immunoreactive neurons, astrocytes and oligodendrocytes/threads semiquantified. Correlations between the two pathological measures and the presence or absence of cardinal PSP symptoms were investigated. Cortical atrophy was more severe in PSP-RS than PSP-P and affected more frontal lobe regions (frontal pole, inferior frontal gyrus). The supramarginal gyrus was atrophic in both subtypes. Additionally, atrophy of the internal globus pallidus, amygdala, and thalamus was more severe in PSP-RS. As expected, more severe frontal lobe tau pathology differentiated PSP-RS from PSP-P. No correlations were found between the degree of atrophy and severity of tau pathology in any region assessed, or between the severity of atrophy or tau pathology and the presence or absence of cardinal PSP symptoms. Our study shows that thalamocortical atrophy is a defining feature of PSP-RS, but this atrophy does not correlate with the presence of any specific cardinal clinical feature. Interestingly, there is a disassociation between tau pathology and atrophy in the brain regions affected in PSP-RS that requires further investigation.


Assuntos
Córtex Cerebral/patologia , Transtornos Parkinsonianos/patologia , Paralisia Supranuclear Progressiva/patologia , Astrócitos/patologia , Atrofia/patologia , Contagem de Células , Diagnóstico Diferencial , Humanos , Imuno-Histoquímica , Neurônios/patologia , Oligodendroglia/patologia
11.
J Alzheimers Dis ; 22(3): 981-4, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20858962

RESUMO

Serum progranulin is decreased in frontotemporal dementia (FTD) patients with progranulin gene (PGRN) mutations. We investigate the utility of prospective serum screening as a surrogate diagnostic marker for progranulin mutations. A commercial ELISA was used to measure progranulin protein concentration in serum from 63 FTD patients and 32 normal controls, and DNA screening then performed. Four patients (2/17 behavioral variant, 2/8 corticobasal syndrome) had abnormally low progranulin levels with PGRN mutations confirmed on DNA testing. Surprisingly, elevated levels were found in 6/16 patients with progressive non-fluent aphasia, the significance of which is unclear. Serum testing is an accurate and cost effective means of predicting PGRN mutations.


Assuntos
Demência Frontotemporal/sangue , Demência Frontotemporal/genética , Peptídeos e Proteínas de Sinalização Intercelular/sangue , Peptídeos e Proteínas de Sinalização Intercelular/genética , Mutação/genética , Idoso , Idoso de 80 Anos ou mais , Biomarcadores/sangue , Feminino , Demência Frontotemporal/epidemiologia , Humanos , Peptídeos e Proteínas de Sinalização Intercelular/biossíntese , Masculino , Programas de Rastreamento/métodos , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Progranulinas , Estudos Prospectivos
12.
Proteomics ; 9(11): 3022-35, 2009 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19526546

RESUMO

We report a quantitative proteomic study to investigate the changes induced in membrane rafts by the inhibition of glycogen synthase kinase-3. Sensitive quantitation of membrane raft proteins using isobaric tagging chemistries was enabled by a novel hybrid proteomic method to isolate low-microgram (10-30 microg) membrane raft protein preparations as unresolved bands in a low-density acrylamide gel. Samples were in-gel digested, differentially tagged and combined for 2-D LC and quantitative MS. Analysis of hippocampal membrane preparations using this approach resulted in a sixfold increase in sensitivity and a threefold increase in the number of quantifiable proteins compared with parallel processing using a traditional in-solution method. Quantitative analysis of membrane raft preparations from a human neuronal cell line treated with glycogen synthase kinase-3 inhibitors SB415286 or lithium chloride, that have been reported to modulate processing of the Alzheimer amyloid precursor protein, identified several protein changes. These included decreases in lamin B1 and lamin B receptor, as well as increases in several endosome regulating rab proteins, rab5, rab7 and rab11 that have been implicated in processing of the amyloid precursor protein in Alzheimer's disease.


Assuntos
Quinase 3 da Glicogênio Sintase/metabolismo , Microdomínios da Membrana/metabolismo , Proteínas de Membrana/metabolismo , Neurônios/metabolismo , Proteômica/métodos , Doença de Alzheimer/metabolismo , Animais , Western Blotting , Linhagem Celular Tumoral , Eletroforese em Gel Bidimensional , Quinase 3 da Glicogênio Sintase/análise , Quinase 3 da Glicogênio Sintase/antagonistas & inibidores , Hipocampo/citologia , Humanos , Modelos Lineares , Masculino , Espectrometria de Massas , Microdomínios da Membrana/química , Proteínas de Membrana/análise , Camundongos , Camundongos Endogâmicos DBA , Neurônios/química , Neurônios/enzimologia , Sensibilidade e Especificidade
13.
Chemistry ; 15(23): 5740-8, 2009 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-19388028

RESUMO

Metal complexes [M(phtpy)(pztpy)](PF(6))(2) (phtpy = 4'-phenyl-2,2':6',2''-terpyridine, pztpy = 4'-(N-piperazinyl)-2,2':6',2''-terpyridine, M = Ru, Os) were prepared and examined spectroscopically and electrochemically. The piperazine attachment was found to significantly modify the photophysical and electrochemical properties compared to the parent bis-terpyridine complexes, causing a red-shift of the (1)MLCT (23 nm, 53.9 eV) and a substantial cathodic shift of the redox potential (0.3 V for Ru, 0.23 V for Os). Self-assembled monolayers (SAMs) of the complexes on polished gold electrodes were generated simply by the in situ formation of a dithiocarbamate (DTC) anchoring group at the terminal piperazinyl nitrogen on the pztpy ligand. Cyclic voltammetry revealed that the monolayers show excellent reversible behaviour and exceptional stability. The high stability of the SAMs is attributed to the strong bidentate attachment to the gold surface of the DTC tether and the favourable low oxidation potentials of the complexes which result from the electron-rich piperazine nitrogen on the pztpy ligand. Such DTC-based SAMs demonstrate a substantial improvement over commonly-employed thiol-based systems, and offer new scope for future development.

14.
Eur J Neurosci ; 25(1): 81-6, 2007 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-17241269

RESUMO

Glycogen synthase kinase-3 (GSK-3) is a serine/threonine kinase regulating diverse cellular functions including metabolism, transcription and cell survival. Numerous intracellular signalling pathways converge on GSK-3 and regulate its activity via inhibitory serine-phosphorylation. Recently, GSK-3 has been involved in learning and memory and in neurodegeneration. Here, we present evidence that implicates GSK-3 in synaptic plasticity. We show that phosphorylation at the inhibitory Ser9 site on GSK-3beta is increased upon induction of long-term potentiation (LTP) in both hippocampal subregions CA1 and the dentate gyrus (DG) in vivo. The increase in inhibitory GSK-3beta phosphorylation is robust and persists for at least one hour postinduction. Furthermore, we find that LTP is impaired in transgenic mice conditionally overexpressing GSK-3beta. The LTP deficits can be attenuated/rescued by chronic treatment with lithium, a GSK-3 inhibitor. These results suggest that the inhibition of GSK-3 facilitates the induction of LTP and this might explain some of the negative effects of GSK-3 on learning and memory. It follows that this role of GSK-3beta in LTP might underlie some of the cognitive dysfunction in diseases where GSK-3 dysfunction has been implicated, including Alzheimer's and other dementias.


Assuntos
Quinase 3 da Glicogênio Sintase/fisiologia , Potenciação de Longa Duração/fisiologia , Animais , Western Blotting/métodos , Relação Dose-Resposta à Radiação , Estimulação Elétrica/métodos , Lateralidade Funcional , Quinase 3 da Glicogênio Sintase/genética , Hipocampo/fisiologia , Hipocampo/efeitos da radiação , Potenciação de Longa Duração/efeitos da radiação , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Fosforilação/efeitos da radiação , Serina/metabolismo , Sinaptofisina/metabolismo , Sinaptossomos/metabolismo , Fatores de Tempo
15.
Chemistry ; 12(17): 4600-10, 2006 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-16557628

RESUMO

A series of N-alkylated derivatives of [Ru(pytpy)(2)]2+ (pytpy=4'-(4-pyridyl)-2,2':6',2''-terpyridine) has been synthesised and characterised. These include both model and functionalised complexes that complement previously reported iron(II) analogues. Reaction of [Ru(pytpy)(2)]2+ with bis[4-(bromomethyl)phenyl]methane leads to the formation of a [2+2] ruthenamacrocycle. Related ferramacrocycles could not be accessed by this route, and instead were prepared in two steps by first reacting bis[4-(bromomethyl)phenyl]methane or 4,4'-bis(bromomethyl)biphenyl with two equivalents of pytpy, and then treating the resulting bis(N-alkylated) product with iron(II) salts.


Assuntos
Compostos Organometálicos/química , Piridinas/química , Rutênio/química , Alquilação , Ligantes , Modelos Moleculares , Conformação Molecular , Estrutura Molecular
17.
Mov Disord ; 20(1): 34-9, 2005 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-15390131

RESUMO

The movement disorders progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD) both deposit tau in degenerating neurons and are considered to be tauopathies. The recently developed scheme for staging tissue degeneration in another tauopathy, frontotemporal dementia [Broe et al., Neurology 2003;60:1005-1011] was applied to pathologically confirmed PSP (n = 24) and CBD (n = 9) cases and correlated with clinical indices. In contrast to frontotemporal dementia, the majority of PSP cases had limited or no visible atrophy, while the pattern of atrophy in CBD cases conformed to the existing staging scheme (all but one case exhibiting substantial visible tissue atrophy). Despite similar clinical severity and disease duration between groups, there was a marked difference between the PSP and CBD cases in pathological disease stage (chi(2) = 8.86; P = 0.03). The degree of global atrophy in PSP appears to be distinct from other tauopathies, while CBD fits the same pattern as other pathological forms of frontotemporal dementia.


Assuntos
Doenças dos Gânglios da Base , Degeneração Neural , Paralisia Supranuclear Progressiva , Proteínas tau/metabolismo , Idoso , Idoso de 80 Anos ou mais , Atrofia , Doenças dos Gânglios da Base/metabolismo , Doenças dos Gânglios da Base/patologia , Distribuição de Qui-Quadrado , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Degeneração Neural/classificação , Degeneração Neural/metabolismo , Degeneração Neural/fisiopatologia , Estudos Prospectivos , Paralisia Supranuclear Progressiva/metabolismo , Paralisia Supranuclear Progressiva/patologia
18.
Inorg Chem ; 43(26): 8346-54, 2004 Dec 27.
Artigo em Inglês | MEDLINE | ID: mdl-15606181

RESUMO

A series of photoreactive complexes of the type Ru(terpy*)(N-N)(L)(2+), where terpy* is 4'-(3,5-ditertiobutylphenyl)-2,2':6',2' '-terpyridine, N-N is the bidentate chelate phen or dmp (phen = 1,10-phenanthroline, dmp = 2,9-dimethyl-1,10-phenanthroline), and L is the monodentate ligand dms, MeBN, or MeOBN (dms = dimethyl sulfide, MeBN = 2,6-dimethyl benzonitrile, MeOBN = 2,6-dimethoxybenzonitrile), has been synthesized and fully characterized by proton NMR spectroscopy, electrospray mass spectrometry, and UV-vis spectroscopy. The X-ray structures of four complexes were also obtained. In neat pyridine, the quantum yields for the photosubsitution of L by pyridine were measured and showed dramatic variations depending on the steric interactions between the spectator bidentate ligand and the leaving monodentate ligand L. The use of dmp instead of phen multiplied the photosubstitution efficiency by a factor of 20-50, depending on L. This effect could be qualitatively correlated to the distortions observed in the X-ray structures of the corresponding complexes. The highly distorted structure of Ru(terpy)(dmp)(dms)(PF(6))(2) showed a very high photosubsitution quantum yield phi = 0.36 in neat pyridine. The high photoreactivity of some of the compounds makes them particularly promising as components of future light-driven molecular machines.

19.
J Am Chem Soc ; 126(28): 8694-701, 2004 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-15250721

RESUMO

Tetra-peri-(tert-butyl-benzo)-di-peri-(pyrimidino)-coronene 1, the parent compound of the nitrogen heterosuperbenzene family N-HSB, is employed as a novel monotopic ligand in the formation of [Pd(eta3-C3H5)(1)]PF6 2 and [Ru(bpy)2(1)](PF6)2 (where bpy = 2,2'-bipyridine 3a and d8-2,2'-bipyridine 3b). These N-coordinated complexes are fully characterized by 1H NMR and IR spectroscopy and ESI-MS. Metal coordination has a profound effect on both the absorption and the emission properties of 1. Pd(II) coordination causes a red-shift in the low-energy absorptions, a decrease in the intensity of the n-pi absorptions, and a quenching of the emission. Ru(II) coordination causes absorption throughout the visible region and creates two new complexes that join an elite group of compounds known as "black" absorbers. 3a and 3b possess two discernible 1MLCT bands. The one of exceptionally low energy (lambda(max) = 615 nm) has an associated (3)MLCT emission (lambda(max) = 880 nm) due to the unprecedented electron delocalization and acceptor properties of the rigid aromatic N-HSB 1. Both Ru(II) complexes are near-IR emitters with unusually protracted emission lifetimes of 320 ns at 77 K. They are photochemically inert, and their electrochemical properties are consistent with the presence of a low-lying pi orbital on 1. The first two reversible reductions (E(1/2) (CH3CN), -0.54 V, -1.01 V vs SCE) are due to the stepwise reduction of 1 and are anodically shifted as compared to [Ru(bpy)3]2+. Temperature- and concentration-dependent NMR studies on 2 and 3a suggest extensive aggregation is occurring in solution.

20.
Brain ; 126(Pt 4): 827-40, 2003 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-12615642

RESUMO

Frontotemporal dementia is a term used to characterize diverse neuropathological conditions that can present with the same clinical phenotype. Five different neuropathologies underlie this disorder. However, consistent frontal and/or temporal neuronal loss and gliosis characterize all cases, the majority having no obvious pathological inclusions. Because neuronal loss and gliosis are consistent features across all cases, the present study aimed to determine the relationship between neuronal loss, gliosis and, for cases with abnormal tau inclusions, intracellular tau deposition. Formalin-fixed brain specimens from sporadic cases with frontotemporal dementia (eight with tau-positive Pick bodies, five with frontotemporal lobar degeneration without inclusions) were compared with those from non-diseased controls (n = 5). Brain specimens were cut into 3 mm coronal slices for evaluation and tissue samples from the superior frontal gyrus were taken for microscopic analysis. Immuno histochemistry for glia-specific proteins (astrocytic glial fibrillary acidic protein and microglial major histocompatibility complex II) and different tau epitopes was performed on 50 microm free-floating sections. Gross patterns of brain atrophy were analysed and upper and lower layer pyramidal neurons and glial cell numbers were quantified. A disease severity scheme was devised using the degree of gross macroscopic frontal and temporal atrophy to establish the relationship between the gliosis and neurodegeneration. In this small sample, the patterns of gross atrophy could be grouped reliably into four stages of severity. These stages were the same across disease groups and correlated with volume- corrected pyramidal neuron densities. In cases with Pick bodies, disease stage also correlated with duration, providing further evidence that these stages represent the progression of degeneration in this limited sample. Whereas there were, on average, many more reactive astrocytes in the cases with Pick bodies than in those with frontotemporal lobar atrophy, there was significant overlap between cases in the degree of astrocytosis. However, a large proportion of the astrocytes in Pick's disease displayed phosphorylated tau immunoreactivity, whereas no tau-positive astrocytes were found in frontotemporal lobar degeneration. The pattern and degree of microglia activation were similar in all the dementia cases analysed, with considerably more activated microglia accumulating in white matter. In this small sample, the abundance of white matter microglia at early disease stages suggests a prominent role for this cell type in the neurodegenerative process. In frontotemporal lobar degeneration, a significant proportion of the activated white matter microglia were tau-2-immunoreactive, suggesting direct involvement in axonal degeneration, possibly via immune processes.


Assuntos
Demência/patologia , Gliose/patologia , Proteínas tau/metabolismo , Adulto , Idoso , Astrócitos/metabolismo , Astrócitos/patologia , Morte Celular , Demência/etiologia , Feminino , Humanos , Masculino , Microglia/patologia , Pessoa de Meia-Idade , Doença de Pick/etiologia , Doença de Pick/patologia
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