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1.
Artigo em Inglês | MEDLINE | ID: mdl-38669595

RESUMO

OBJECTIVES: To investigate the association between varying degrees of abnormality in the uterine artery Doppler pulsatility index (UtA-PI) and adverse perinatal outcomes. METHODS: Prospective study of 33,364 women who gave birth to singleton, non-anomalous babies in Oxford, following universal measurement of UtA-PI in mid-pregnancy. Relative risk ratios for the primary outcomes of extended perinatal mortality and live birth with severe small-for-gestational-age (SGA) were calculated by multinomial logistic regression, for early preterm birth (<34+0) and late preterm/term birth (≥34+0). The risks were also investigated for iatrogenic preterm birth or a composite adverse outcome before 34+0 weeks. RESULTS: Compared with women with normal UtA-PI, the risk of extended perinatal mortality before 34+0 weeks was higher in women with UtA-PI >90th centile (RRR 4.7, 95% CI 2.7-8.0, p<0.001), but this was not demonstrated in later births. The risk of severe SGA birth was strongly associated with abnormal UtA-PI for both early births (RRR 26.0, 95% CI 11.6-58.2, p<0.001), and later births (RRR 2.3, 95% CI 1.8-2.9, p<0.001). Women with a raised UtA-PI were more likely to undergo early iatrogenic birth (RRR 7.8, 95% CI 5.5-11.2, p<0.001). For each of the outcomes and the composite outcome, the risk increased significantly in association with the degree of abnormality, through the 90th, 90-94th, 95-99th and >99th centiles (ptrend<0.001). CONCLUSIONS: An elevated UtA-PI is a key predictor of iatrogenic preterm birth, severe SGA and perinatal loss up to 34+0 weeks. It is the 90th centile that should be used, and management should be further tailored to the degree of abnormality, as pregnancies with very raised UtA-PI measurements constitute a group at extreme risk. This article is protected by copyright. All rights reserved.

2.
Nat Struct Mol Biol ; 30(12): 2009-2019, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37945741

RESUMO

p97, also known as valosin-containing protein, is an essential cytosolic AAA+ (ATPases associated with diverse cellular activities) hexamer that unfolds substrate polypeptides to support protein homeostasis and macromolecular disassembly. Distinct sets of p97 adaptors guide cellular functions but their roles in direct control of the hexamer are unclear. The UBXD1 adaptor localizes with p97 in critical mitochondria and lysosome clearance pathways and contains multiple p97-interacting domains. Here we identify UBXD1 as a potent p97 ATPase inhibitor and report structures of intact human p97-UBXD1 complexes that reveal extensive UBXD1 contacts across p97 and an asymmetric remodeling of the hexamer. Conserved VIM, UBX and PUB domains tether adjacent protomers while a connecting strand forms an N-terminal domain lariat with a helix wedged at the interprotomer interface. An additional VIM-connecting helix binds along the second (D2) AAA+ domain. Together, these contacts split the hexamer into a ring-open conformation. Structures, mutagenesis and comparisons to other adaptors further reveal how adaptors containing conserved p97-remodeling motifs regulate p97 ATPase activity and structure.


Assuntos
Proteínas de Ciclo Celular , Humanos , Proteína com Valosina/metabolismo , Ligação Proteica , Estrutura Terciária de Proteína , Proteínas de Ciclo Celular/metabolismo
3.
bioRxiv ; 2023 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-37645969

RESUMO

Microtubule-associated protein tau (MAPT/tau) accumulates in a family of neurodegenerative diseases, including Alzheimer's disease (AD). In disease, tau is aberrantly modified by post-translational modifications (PTMs), including hyper-phosphorylation. However, it is often unclear which of these PTMs contribute to tau's accumulation or what mechanisms might be involved. To explore these questions, we focused on a cleaved proteoform of tau (tauC3), which selectively accumulates in AD and was recently shown to be degraded by its direct binding to the E3 ubiquitin ligase, CHIP. Here, we find that phosphorylation of tauC3 at a single residue, pS416, is sufficient to block its interaction with CHIP. A co-crystal structure of CHIP bound to the C-terminus of tauC3 revealed the mechanism of this clash and allowed design of a mutation (CHIPD134A) that partially restores binding and turnover of pS416 tauC3. We find that pS416 is produced by the known AD-associated kinase, MARK2/Par-1b, providing a potential link to disease. In further support of this idea, an antibody against pS416 co-localizes with tauC3 in degenerative neurons within the hippocampus of AD patients. Together, these studies suggest a discrete molecular mechanism for how phosphorylation at a specific site contributes to accumulation of an important tau proteoform.

4.
J Mol Biol ; 435(11): 168026, 2023 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-37330289

RESUMO

Hyper-phosphorylated tau accumulates as insoluble fibrils in Alzheimer's disease (AD) and related dementias. The strong correlation between phosphorylated tau and disease has led to an interest in understanding how cellular factors discriminate it from normal tau. Here, we screen a panel of chaperones containing tetratricopeptide repeat (TPR) domains to identify those that might selectively interact with phosphorylated tau. We find that the E3 ubiquitin ligase, CHIP/STUB1, binds 10-fold more strongly to phosphorylated tau than unmodified tau. The presence of even sub-stoichiometric concentrations of CHIP strongly suppresses aggregation and seeding of phosphorylated tau. We also find that CHIP promotes rapid ubiquitination of phosphorylated tau, but not unmodified tau, in vitro. Binding to phosphorylated tau requires CHIP's TPR domain, but the binding mode is partially distinct from the canonical one. In cells, CHIP restricts seeding by phosphorylated tau, suggesting that it could be an important barrier in cell-to-cell spreading. Together, these findings show that CHIP recognizes a phosphorylation-dependent degron on tau, establishing a pathway for regulating the solubility and turnover of this pathological proteoform.


Assuntos
Chaperonas Moleculares , Agregados Proteicos , Ubiquitina-Proteína Ligases , Proteínas tau , Humanos , Doença de Alzheimer/metabolismo , Chaperonas Moleculares/química , Fosforilação , Proteínas tau/química , Ubiquitina-Proteína Ligases/química , Ubiquitinação
5.
bioRxiv ; 2023 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-37292947

RESUMO

p97/VCP is an essential cytosolic AAA+ ATPase hexamer that extracts and unfolds substrate polypeptides during protein homeostasis and degradation. Distinct sets of p97 adapters guide cellular functions but their roles in direct control of the hexamer are unclear. The UBXD1 adapter localizes with p97 in critical mitochondria and lysosome clearance pathways and contains multiple p97-interacting domains. We identify UBXD1 as a potent p97 ATPase inhibitor and report structures of intact p97:UBXD1 complexes that reveal extensive UBXD1 contacts across p97 and an asymmetric remodeling of the hexamer. Conserved VIM, UBX, and PUB domains tether adjacent protomers while a connecting strand forms an N-terminal domain lariat with a helix wedged at the interprotomer interface. An additional VIM-connecting helix binds along the second AAA+ domain. Together these contacts split the hexamer into a ring-open conformation. Structures, mutagenesis, and comparisons to other adapters further reveal how adapters containing conserved p97-remodeling motifs regulate p97 ATPase activity and structure.

6.
J Am Chem Soc ; 2023 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-36753572

RESUMO

The aggregation of tau into insoluble fibrils is a defining feature of neurodegenerative tauopathies. However, tau has a positive overall charge and is highly soluble; so, polyanions, such as heparin, are typically required to promote its aggregation in vitro. There are dozens of polyanions in living systems, and it is not clear which ones might promote this process. Here, we systematically measure the ability of 37 diverse, anionic biomolecules to initiate tau aggregation using either wild-type (WT) tau or the disease-associated P301S mutant. We find that polyanions from many different structural classes can promote fibril formation and that P301S tau is sensitive to a greater number of polyanions (28/37) than WT tau (21/37). We also find that some polyanions preferentially reduce the lag time of the aggregation reactions, while others enhance the elongation rate, suggesting that they act on partially distinct steps. From the resulting structure-activity relationships, the valency of the polyanion seems to be an important chemical feature such that anions with low valency tend to be weaker aggregation inducers, even at the same overall charge. Finally, the identity of the polyanion influences fibril morphology based on electron microscopy and limited proteolysis. These results provide insights into the crucial role of polyanion-tau interactions in modulating tau conformational dynamics with implications for understanding the tau aggregation landscape in a complex cellular environment.

7.
Methods Mol Biol ; 2444: 243-269, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35290642

RESUMO

With improvements in biophysical approaches, there is growing interest in characterizing large, flexible multi-protein complexes. The use of recombinant baculoviruses to express heterologous genes in cultured insect cells has advantages for the expression of human protein complexes because of the ease of co-expressing multiple proteins in insect cells and the presence of a conserved post-translational machinery that introduces many of the same modifications found in human cells. Here we describe the preparation of recombinant baculoviruses expressing DNA ligase IIIα, XRCC1, and TDP1, their subsequent co-expression in cultured insect cells, the purification of complexes containing DNA ligase IIIα from insect cell lysates, and their characterization by multi-angle light scattering linked to size exclusion chromatography and negative stain electron microscopy.


Assuntos
DNA Ligases , Proteínas de Ligação a DNA , Animais , DNA Ligase Dependente de ATP/genética , DNA Ligase Dependente de ATP/metabolismo , DNA Ligases/química , Proteínas de Ligação a DNA/metabolismo , Humanos , Insetos/metabolismo , Proteínas de Ligação a Poli-ADP-Ribose , Proteína 1 Complementadora Cruzada de Reparo de Raio-X , Proteínas de Xenopus/metabolismo
8.
Mol Cell ; 81(17): 3496-3508.e5, 2021 09 02.
Artigo em Inglês | MEDLINE | ID: mdl-34380015

RESUMO

The Hsp90 chaperone promotes folding and activation of hundreds of client proteins in the cell through an ATP-dependent conformational cycle guided by distinct cochaperone regulators. The FKBP51 immunophilin binds Hsp90 with its tetratricopeptide repeat (TPR) domain and catalyzes peptidyl-prolyl isomerase (PPIase) activity during folding of kinases, nuclear receptors, and tau. Here we determined the cryoelectron microscopy (cryo-EM) structure of the human Hsp90:FKBP51:p23 complex to 3.3 Å, which, together with mutagenesis and crosslinking analyses, reveals the basis for cochaperone binding to Hsp90 during client maturation. A helix extension in the TPR functions as a key recognition element, interacting across the Hsp90 C-terminal dimer interface presented in the closed, ATP conformation. The PPIase domain is positioned along the middle domain, adjacent to Hsp90 client binding sites, whereas a single p23 makes stabilizing interactions with the N-terminal dimer. With this architecture, FKBP51 is positioned to act on specific client residues presented during Hsp90-catalyzed remodeling.


Assuntos
Proteínas de Choque Térmico HSP90/química , Proteínas de Ligação a Tacrolimo/química , Sequência de Aminoácidos , Sítios de Ligação , Biomarcadores Tumorais/química , Biomarcadores Tumorais/metabolismo , Microscopia Crioeletrônica/métodos , Proteínas de Choque Térmico HSP90/metabolismo , Humanos , Chaperonas Moleculares/química , Chaperonas Moleculares/metabolismo , Conformação Molecular , Ligação Proteica , Proteínas de Ligação a Tacrolimo/metabolismo , Proteína Tumoral 1 Controlada por Tradução
9.
Preprint em Inglês | bioRxiv | ID: ppbiorxiv-443524

RESUMO

The SARS-CoV-2 protein Nsp2 has been implicated in a wide range of viral processes, but its exact functions, and the structural basis of those functions, remain unknown. Here, we report an atomic model for full-length Nsp2 obtained by combining cryo-electron microscopy with deep learning-based structure prediction from AlphaFold2. The resulting structure reveals a highly-conserved zinc ion-binding site, suggesting a role for Nsp2 in RNA binding. Mapping emerging mutations from variants of SARS-CoV-2 on the resulting structure shows potential host-Nsp2 interaction regions. Using structural analysis together with affinity tagged purification mass spectrometry experiments, we identify Nsp2 mutants that are unable to interact with the actin-nucleation-promoting WASH protein complex or with GIGYF2, an inhibitor of translation initiation and modulator of ribosome-associated quality control. Our work suggests a potential role of Nsp2 in linking viral transcription within the viral replication-transcription complexes (RTC) to the translation initiation of the viral message. Collectively, the structure reported here, combined with mutant interaction mapping, provides a foundation for functional studies of this evolutionary conserved coronavirus protein and may assist future drug design.

10.
Sci Adv ; 7(16)2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33853786

RESUMO

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) macrodomain within the nonstructural protein 3 counteracts host-mediated antiviral adenosine diphosphate-ribosylation signaling. This enzyme is a promising antiviral target because catalytic mutations render viruses nonpathogenic. Here, we report a massive crystallographic screening and computational docking effort, identifying new chemical matter primarily targeting the active site of the macrodomain. Crystallographic screening of 2533 diverse fragments resulted in 214 unique macrodomain-binders. An additional 60 molecules were selected from docking more than 20 million fragments, of which 20 were crystallographically confirmed. X-ray data collection to ultra-high resolution and at physiological temperature enabled assessment of the conformational heterogeneity around the active site. Several fragment hits were confirmed by solution binding using three biophysical techniques (differential scanning fluorimetry, homogeneous time-resolved fluorescence, and isothermal titration calorimetry). The 234 fragment structures explore a wide range of chemotypes and provide starting points for development of potent SARS-CoV-2 macrodomain inhibitors.


Assuntos
Domínio Catalítico/fisiologia , Ligação Proteica/fisiologia , Proteínas não Estruturais Virais/metabolismo , Domínio Catalítico/genética , Cristalografia por Raios X , Humanos , Modelos Moleculares , Simulação de Acoplamento Molecular , Conformação Proteica , SARS-CoV-2/genética , SARS-CoV-2/fisiologia , Proteínas não Estruturais Virais/genética , Tratamento Farmacológico da COVID-19
11.
bioRxiv ; 2020 Nov 24.
Artigo em Inglês | MEDLINE | ID: mdl-33269349

RESUMO

The SARS-CoV-2 macrodomain (Mac1) within the non-structural protein 3 (Nsp3) counteracts host-mediated antiviral ADP-ribosylation signalling. This enzyme is a promising antiviral target because catalytic mutations render viruses non-pathogenic. Here, we report a massive crystallographic screening and computational docking effort, identifying new chemical matter primarily targeting the active site of the macrodomain. Crystallographic screening of diverse fragment libraries resulted in 214 unique macrodomain-binding fragments, out of 2,683 screened. An additional 60 molecules were selected from docking over 20 million fragments, of which 20 were crystallographically confirmed. X-ray data collection to ultra-high resolution and at physiological temperature enabled assessment of the conformational heterogeneity around the active site. Several crystallographic and docking fragment hits were validated for solution binding using three biophysical techniques (DSF, HTRF, ITC). Overall, the 234 fragment structures presented explore a wide range of chemotypes and provide starting points for development of potent SARS-CoV-2 macrodomain inhibitors.

12.
Preprint em Inglês | bioRxiv | ID: ppbiorxiv-393405

RESUMO

The SARS-CoV-2 macrodomain (Mac1) within the non-structural protein 3 (Nsp3) counteracts host-mediated antiviral ADP-ribosylation signalling. This enzyme is a promising antiviral target because catalytic mutations render viruses non-pathogenic. Here, we report a massive crystallographic screening and computational docking effort, identifying new chemical matter primarily targeting the active site of the macrodomain. Crystallographic screening of diverse fragment libraries resulted in 214 unique macrodomain-binding fragments, out of 2,683 screened. An additional 60 molecules were selected from docking over 20 million fragments, of which 20 were crystallographically confirmed. X-ray data collection to ultra-high resolution and at physiological temperature enabled assessment of the conformational heterogeneity around the active site. Several crystallographic and docking fragment hits were validated for solution binding using three biophysical techniques (DSF, HTRF, ITC). Overall, the 234 fragment structures presented explore a wide range of chemotypes and provide starting points for development of potent SARS-CoV-2 macrodomain inhibitors.

13.
J Sci Med Sport ; 23(11): 1074-1079, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32646745

RESUMO

OBJECTIVES: To investigate diurnal patterns of sedentary time and interruptions to sedentary time and their associations with achievement of pre-meal glucose, post-meal glucose, bedtime glucose and the dawn phenomenon targets and with duration of hypoglycaemia, euglycaemia, hyperglycaemia and above target range. DESIGN: Intensive longitudinal study. METHODS: In 37 adults with type 2 diabetes, the FreeStyle Libre and activPAL3 were used to monitor glucose and sedentary time and interruptions to sedentary time in the morning (07:00-12:00), afternoon (12:00-17:00) and evening (17:00-23:00) for 14 days. Diurnal patterns of sedentary behaviour and associations with glycaemic indices were assessed using repeated measures ANOVA and linear regressions. RESULTS: Sedentary time was significantly higher in the evening (43.47±7.37min/h) than the morning (33.34±8.44min/h) and afternoon (37.26±8.28min/h). Interruptions to sedentary time were significantly lower in the evening (2.64±0.74n/h) than the morning (3.69±1.08n/h) and afternoon (3.06±0.87n/h). Sedentary time in the morning and afternoon was associated with lower achievement of the dawn phenomenon target. Sedentary time in the evening was associated with lower achievement of post-lunch glucose target. Interruptions to sedentary time in the morning and afternoon were associated with higher achievement of pre-dinner glucose target. Interruptions to sedentary time in the evening showed beneficial associations with achievement of post-dinner glucose and bedtime glucose targets and euglycaemia. CONCLUSIONS: Prolonged sedentary behaviour is high in the evening. Interruptions to sedentary time, particularly in the evening, have beneficial associations with glycaemic indices. Interventions targeting interruptions to sedentary time in the evening may be more clinically relevant.


Assuntos
Ritmo Circadiano , Diabetes Mellitus Tipo 2/sangue , Índice Glicêmico , Comportamento Sedentário , Actigrafia , Idoso , Análise de Variância , Glicemia/análise , Carboidratos da Dieta , Metabolismo Energético , Feminino , Humanos , Modelos Lineares , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Período Pós-Prandial
14.
Proc Natl Acad Sci U S A ; 117(25): 14127-14138, 2020 06 23.
Artigo em Inglês | MEDLINE | ID: mdl-32522879

RESUMO

Xeroderma pigmentosum group G (XPG) protein is both a functional partner in multiple DNA damage responses (DDR) and a pathway coordinator and structure-specific endonuclease in nucleotide excision repair (NER). Different mutations in the XPG gene ERCC5 lead to either of two distinct human diseases: Cancer-prone xeroderma pigmentosum (XP-G) or the fatal neurodevelopmental disorder Cockayne syndrome (XP-G/CS). To address the enigmatic structural mechanism for these differing disease phenotypes and for XPG's role in multiple DDRs, here we determined the crystal structure of human XPG catalytic domain (XPGcat), revealing XPG-specific features for its activities and regulation. Furthermore, XPG DNA binding elements conserved with FEN1 superfamily members enable insights on DNA interactions. Notably, all but one of the known pathogenic point mutations map to XPGcat, and both XP-G and XP-G/CS mutations destabilize XPG and reduce its cellular protein levels. Mapping the distinct mutation classes provides structure-based predictions for disease phenotypes: Residues mutated in XP-G are positioned to reduce local stability and NER activity, whereas residues mutated in XP-G/CS have implied long-range structural defects that would likely disrupt stability of the whole protein, and thus interfere with its functional interactions. Combined data from crystallography, biochemistry, small angle X-ray scattering, and electron microscopy unveil an XPG homodimer that binds, unstacks, and sculpts duplex DNA at internal unpaired regions (bubbles) into strongly bent structures, and suggest how XPG complexes may bind both NER bubble junctions and replication forks. Collective results support XPG scaffolding and DNA sculpting functions in multiple DDR processes to maintain genome stability.


Assuntos
Síndrome de Cockayne/genética , Proteínas de Ligação a DNA/química , Endonucleases/química , Proteínas Nucleares/química , Mutação Puntual , Fatores de Transcrição/química , Xeroderma Pigmentoso/genética , Sítios de Ligação , Sequência Conservada , DNA/metabolismo , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Endonucleases/genética , Endonucleases/metabolismo , Estabilidade Enzimática , Humanos , Simulação de Dinâmica Molecular , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Fenótipo , Ligação Proteica , Dobramento de Proteína , Multimerização Proteica , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
15.
Nat Struct Mol Biol ; 27(5): 406-416, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32313240

RESUMO

The ClpAP complex is a conserved bacterial protease that unfolds and degrades proteins targeted for destruction. The ClpA double-ring hexamer powers substrate unfolding and translocation into the ClpP proteolytic chamber. Here, we determined high-resolution structures of wild-type Escherichia coli ClpAP undergoing active substrate unfolding and proteolysis. A spiral of pore loop-substrate contacts spans both ClpA AAA+ domains. Protomers at the spiral seam undergo nucleotide-specific rearrangements, supporting substrate translocation. IGL loops extend flexibly to bind the planar, heptameric ClpP surface with the empty, symmetry-mismatched IGL pocket maintained at the seam. Three different structures identify a binding-pocket switch by the IGL loop of the lowest positioned protomer, involving release and re-engagement with the clockwise pocket. This switch is coupled to a ClpA rotation and a network of conformational changes across the seam, suggesting that ClpA can rotate around the ClpP apical surface during processive steps of translocation and proteolysis.


Assuntos
Endopeptidase Clp/química , Endopeptidase Clp/metabolismo , Proteínas de Escherichia coli/química , Proteínas de Escherichia coli/metabolismo , Escherichia coli/química , Escherichia coli/metabolismo , Trifosfato de Adenosina/análogos & derivados , Trifosfato de Adenosina/metabolismo , Microscopia Crioeletrônica , DNA Helicases/metabolismo , Endopeptidase Clp/genética , Escherichia coli/genética , Proteínas de Escherichia coli/genética , Modelos Moleculares , Complexos Multiproteicos , Conformação Proteica , Desdobramento de Proteína , Transativadores/metabolismo
16.
Eur J Appl Physiol ; 120(1): 171-179, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31705275

RESUMO

PURPOSE: To investigate how the pattern of sedentary behaviour affects intra-day glucose regulation in type 2 diabetes. METHODS: This intensive longitudinal study was conducted in 37 participants with type 2 diabetes (age, 62.8 ± 10.5 years). Glucose and sedentary behaviour/physical activity were assessed with a continuous glucose monitoring (Abbott FreeStyle Libre) and an activity monitor (activPAL3) for 14 days. Multiple regression models with generalised estimating equations (GEEs) approach were used to assess the associations of sedentary time and breaks in sedentary time with pre-breakfast glucose, pre-lunch glucose, pre-dinner glucose, post-breakfast glucose, post-lunch glucose, post-dinner glucose, bedtime glucose, the dawn phenomenon, time in target glucose range (TIR, glucose 3.9-10 mmol/L) and time above target glucose range (TAR, glucose > 10 mmol/L). RESULTS: Sedentary time was associated with higher pre-breakfast glucose (p = 0.001), pre-dinner glucose (p < 0.001), post-lunch glucose (p = 0.005), post-dinner glucose (p = 0.013) and the dawn phenomenon (p < 0.001). Breaks in sedentary time were associated with lower pre-breakfast glucose (p = 0.023), pre-dinner glucose (p = 0.023), post-breakfast glucose (p < 0.001) and the dawn phenomenon (p = 0.004). The association between sedentary time and less TIR (p = 0.022) and the association between breaks in sedentary time and more TIR (p = 0.001) were also observed. CONCLUSIONS: Reducing sedentary time and promoting breaks in sedentary time could be clinically relevant to improve intra-day glucose regulation in type 2 diabetes.


Assuntos
Glicemia/metabolismo , Diabetes Mellitus Tipo 2/sangue , Comportamento Sedentário , Idoso , Diabetes Mellitus Tipo 2/fisiopatologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Período Pós-Prandial
17.
J Sci Med Sport ; 22(7): 808-813, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30770192

RESUMO

OBJECTIVES: This study aimed to investigate dose-response between frequency of breaks in sedentary time and glucose control. DESIGN: Randomised three-treatment, two-period balanced incomplete block trial. METHODS: Twelve adults with type 2 diabetes (age, 60±11years; body mass index, 30.2±4.7kg/m2) participated in two of the following treatment conditions: sitting for 7h interrupted by 3min light-intensity walking breaks every (1) 60min (Condition 1), (2) 30min (Condition 2), and (3) 15min (Condition 3). Postprandial glucose incremental area under the curves (iAUCs) and 21-h glucose total area under the curve (AUC) were measured using continuous glucose monitoring. Standardised meals were provided. RESULTS: Compared with Condition 1 (6.7±0.8mmolL-1×3.5h-1), post-breakfast glucose iAUC was reduced for Condition 3 (3.5±0.9 mmolL-1×3.5h-1, p˂0.04). Post-lunch glucose iAUC was lower in Condition 3 (1.3±0.9mmolL-1×3.5h-1, p˂0.03) and Condition 2 (2.1±0.7mmolL-1×3.5h-1, p˂0.05) relative to Condition 1 (4.6±0.8mmolL-1×3.5h-1). Condition 3 (1.0±0.7mmolL-1×3.5h-1, p=0.02) and Condition 2 (1.6±0.6mmolL-1×3.5h-1, p˂0.04) attenuated post-dinner glucose iAUC compared with Condition 1 (4.0±0.7mmolL-1×3.5h-1). Cumulative 10.5-h postprandial glucose iAUC was lower in Condition 3 than Condition 1 (p=0.02). Condition 3 reduced 21-h glucose AUC compared with Condition 1 (p<0.001) and Condition 2 (p=0.002). However, post-breakfast glucose iAUC, cumulative 10.5-h postprandial glucose iAUC and 21-h glucose AUC were not different between Condition 2 and Condition 1 (p˃0.05). CONCLUSIONS: There could be dose-response between frequency of breaks in sedentary time and glucose. Interrupting sedentary time every 15min could produce better glucose control.


Assuntos
Glicemia/metabolismo , Diabetes Mellitus Tipo 2/sangue , Comportamento Sedentário , Caminhada/fisiologia , Idoso , Biomarcadores/metabolismo , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Período Pós-Prandial , Estudo de Prova de Conceito , Postura Sentada , Posição Ortostática , Fatores de Tempo
18.
Diabetes Res Clin Pract ; 146: 289-299, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30399393

RESUMO

AIMS: To assess continuous glucose monitoring (CGM) derived intra-day glucose profiles using global guideline for type 2 diabetes recommended by the International Diabetes Federation (IDF). METHODS: The Cochrane Library, MEDLINE, PubMed, CINAHL and Science Direct were searched to identify observational studies reporting intra-day glucose profiles using CGM in people with type 2 diabetes on any anti-diabetes agents. Overall and subgroup analyses were conducted to summarise mean differences between reported glucose profiles (fasting glucose, pre-meal glucose, postprandial glucose and post-meal glucose spike/excursion) and the IDF targets. RESULTS: Twelve observational studies totalling 731 people were included. Pooled fasting glucose (0.81 mmol/L, 95% CI, 0.53-1.09 mmol/L), postprandial glucose after breakfast (1.63 mmol/L, 95% CI, 0.79-2.48 mmol/L) and post-breakfast glucose spike (1.05 mmol/L, 95% CI, 0.13-1.96 mmol/L) were significantly higher than the IDF targets. Pre-lunch glucose, pre-dinner glucose and postprandial glucose after lunch and dinner were above the IDF targets but not significantly. Subgroup analysis showed significantly higher fasting glucose and postprandial glucose after breakfast in all groups: HbA1c <7% and ≥7% (53 mmol/mol) and duration of diabetes <10 years and ≥10 years. CONCLUSIONS: Independent of HbA1c, fasting glucose and postprandial glucose after breakfast are not well-controlled in type 2 diabetes.


Assuntos
Automonitorização da Glicemia/métodos , Diabetes Mellitus Tipo 2/terapia , Adulto , Idoso , Diabetes Mellitus Tipo 2/patologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
19.
Prev Med Rep ; 12: 94-100, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30214853

RESUMO

The aim of this study was to investigate the associations of accelerometer-assessed sedentary time and breaks in sedentary time with 24-h events and duration of hypoglycaemia (<3.9 mmol/l), euglycaemia (3.9-7.8 mmol/l), hyperglycaemia (>7.8 mmol/l) and above target glucose (>9 mmol/l). Thirty-seven participants with type 2 diabetes (age, 62.8 ±â€¯10.5 years; body mass index, 29.6 ±â€¯6.8 kg/m2) in Glasgow, United Kingdom were enrolled between February 2016 and February 2017. Participants wore an activity monitor (activPAL3) recording the time and pattern of sedentary behaviour and a continuous glucose monitoring (CGM, Abbott FreeStyle Libre) for up to 14 days. Linear regression analyses were used to investigate the associations. Participants spent 3.7%, 64.7%, 32.1% and 19.2% of recording h/day in hypoglycaemia, euglycaemia, hyperglycaemia and above target, respectively. There was a negative association between sedentary time and time in euglycaemia (ß = -0.44, 95% CI -0.86; -0.03, p = 0.04). There was a trend towards a positive association between sedentary time and time in hyperglycaemia (ß = 0.36, 95% CI -0.05; 0.78, p = 0.08). Breaks in sedentary time was associated with higher time in euglycaemia (ß = 0.38, 95% CI 0.00; 0.75, p = 0.04). To conclude, in individuals with type 2 diabetes, more time spent in unbroken and continuous sedentary behaviour was associated with poorer glucose control. Conversely, interrupting sedentary time with frequent breaks appears to improve glycaemic control. Therefore, this should be considered as a simple adjunct therapy to improve clinical outcomes in type 2 diabetes.

20.
Case Rep Infect Dis ; 2017: 1402320, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28386491

RESUMO

Mycotic pseudoaneurysm of aorta following cardiac surgery is rare but is highly fatal if it is unrecognized and untreated. Here, we report a case of a 45-year-old male patient who presented with rapidly progressive multiple pseudoaneurysms of the ascending aorta infected with multidrug resistant (MDR) Pseudomonas aeruginosa at 5 weeks after cardiac transplantation, on a background of prior bridging therapy with left ventricular assistant device (LVAD). The patient was successfully treated with the newer cephalosporin, Ceftolozane/Tazobactam, in combination with surgery. This is the first reported case of mycotic pseudoaneurysm infected with MDR Pseudomonas. This case also highlights the importance of high vigilance and timely multimodality treatment in the diagnosis and management of mycotic pseudoaneurysm following cardiac transplant, especially in patients who had LVAD.

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