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1.
BJOG ; 126(4): 459-470, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30230190

RESUMO

OBJECTIVE: Evidence on the impact of leisure time physical activity (LTPA) in pregnancy on birth size is inconsistent. We aimed to examine the association between LTPA during early and late pregnancy and newborn anthropometric outcomes. DESIGN: Individual level meta-analysis, which reduces heterogeneity across studies. SETTING: A consortium of eight population-based studies (seven European and one US) comprising 72 694 participants. METHODS: Generalised linear models with consistent inclusion of confounders (gestational age, sex, parity, maternal age, education, ethnicity, BMI, smoking, and alcohol intake) were used to test associations between self-reported LTPA at either early (8-18 weeks gestation) or late pregnancy (30+ weeks) and the outcomes. Results were pooled using random effects meta-analyses. MAIN OUTCOME MEASURES: Birth weight, large-for-gestational age (LGA), macrosomia, small-for-gestational age (SGA), % body fat, and ponderal index at birth. RESULTS: Late, but not early, gestation maternal moderate to vigorous physical activity (MVPA), vigorous activity, and LTPA energy expenditure were modestly inversely associated with BW, LGA, macrosomia, and ponderal index, without heterogeneity (all: I2  = 0%). For each extra hour/week of MVPA, RR for LGA and macrosomia were 0.97 (95% CI: 0.96, 0.98) and 0.96 (95% CI: 0.94, 0.98), respectively. Associations were only modestly reduced after additional adjustments for maternal BMI and gestational diabetes. No measure of LTPA was associated with risk for SGA. CONCLUSIONS: Physical activity in late, but not early, pregnancy is consistently associated with modestly lower risk of LGA and macrosomia, but not SGA. TWEETABLE ABSTRACT: In an individual participant meta-analysis, late pregnancy moderate to vigorous physical activity modestly reduced birth size outcomes.


Assuntos
Peso ao Nascer , Exercício Físico , Macrossomia Fetal/epidemiologia , Recém-Nascido Pequeno para a Idade Gestacional , Tecido Adiposo , Adulto , Estudos de Coortes , Diabetes Gestacional/epidemiologia , Metabolismo Energético , Feminino , Humanos , Recém-Nascido , Modelos Lineares , Obesidade/epidemiologia , Sobrepeso/epidemiologia , Gravidez , Complicações na Gravidez/epidemiologia , Primeiro Trimestre da Gravidez , Segundo Trimestre da Gravidez , Terceiro Trimestre da Gravidez , Fatores de Proteção , Fatores de Risco , Adulto Jovem
2.
Mol Psychiatry ; 22(7): 1044-1055, 2017 07.
Artigo em Inglês | MEDLINE | ID: mdl-27137743

RESUMO

Post-traumatic stress disorder (PTSD) is characterized by exaggerated fear expression and impaired fear extinction. The underlying molecular and cellular mechanisms of PTSD are largely unknown. The current pharmacological and non-pharmacological treatments for PTSD are either ineffective or temporary with high relapse rates. Here we report that adiponectin-deficient mice exhibited normal contextual fear conditioning but displayed slower extinction learning. Infusions of adiponectin into the dentate gyrus (DG) of the hippocampus in fear-conditioned mice facilitated extinction of contextual fear. Whole-cell patch-clamp recordings in brain slices revealed that intrinsic excitability of DG granule neurons was enhanced by adiponectin deficiency and suppressed after treatment with the adiponectin mimetic AdipoRon, which were associated with increased input resistance and hyperpolarized resting membrane potential, respectively. Moreover, deletion of AdipoR2, but not AdipoR1 in the DG, resulted in augmented fear expression and reduced extinction, accompanied by intrinsic hyperexcitability of DG granule neurons. Adiponectin and AdipoRon failed to induce facilitation of fear extinction and elicit inhibition of intrinsic excitability of DG neurons in AdipoR2 knockout mice. These results indicated that adiponectin action via AdipoR2 was both necessary and sufficient for extinction of contextual fear and intrinsic excitability of DG granule neurons, implying that enhancing or dampening DG neuronal excitability may cause resistance to or facilitation of extinction. Therefore, our findings provide a functional link between adiponectin/AdipoR2 activation, DG neuronal excitability and contextual fear extinction, and suggest that targeting adiponectin/AdipoR2 may be used to strengthen extinction-based exposure therapies for PTSD.


Assuntos
Adiponectina/metabolismo , Giro Denteado/metabolismo , Receptores de Adiponectina/metabolismo , Potenciais de Ação/fisiologia , Adiponectina/deficiência , Adiponectina/genética , Animais , Condicionamento Clássico/fisiologia , Modelos Animais de Doenças , Extinção Psicológica/fisiologia , Medo/fisiologia , Feminino , Hipocampo , Aprendizagem/fisiologia , Sistema Límbico , Masculino , Potenciais da Membrana , Erros Inatos do Metabolismo/genética , Erros Inatos do Metabolismo/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Neurônios/fisiologia , Técnicas de Patch-Clamp , Córtex Pré-Frontal/fisiologia , Transtornos de Estresse Pós-Traumáticos/metabolismo
3.
Artigo em Inglês | MEDLINE | ID: mdl-38126041

RESUMO

The roles and responsibilities of radiation therapists (RTTs) are many and varied. Professional expectations are influenced by the technology available, as well as the level of autonomy RTTs have in their daily practice. This professional range requires RTTs to possess a unique set of ever evolving skills, posing challenges from an educational perspective. Teaching these "advanced skills" has been the ambition the ESTRO Advanced Skills in Modern Radiotherapy course. In the 10th year of this course, the Faculty look back and reflect on how our programme has evolved and what it has achieved.

4.
Mult Scler ; 19(5): 631-8, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23069874

RESUMO

BACKGROUND: Cognitive decline has been recognised as a frequent symptom in multiple sclerosis (MS). Cholinesterase inhibitors (ChEIs) are employed for the treatment of Alzheimer's disease, but there is some evidence that ChEIs might also be effective in MS patients with cognitive deficits, particularly deficits of memory function. OBJECTIVE: The aim of this study was to evaluate efficacy on memory function and safety of the ChEI rivastigmine in MS patients with cognitive deficits as measured by the change from baseline of the total recall score of the selective reminding test (SRT) after 16 weeks of treatment. METHODS: Efficacy and safety of rivastigmine were analysed in a 16-week, multicentre, double-blind, randomised, placebo-controlled study, followed by an optional one-year open-label treatment phase. Effects of rivastigmine and placebo were compared by an analysis of covariance. RESULTS: In total, 86 patients were enrolled. Patients who received rivastigmine (n = 43) showed a non-significant increase in total recall score (sum of all words immediately recalled over all six trials) over placebo (n = 38) after 16 weeks of treatment (p = 0.2576). Other outcome measures provided no evidence supporting benefits of rivastigmine. Treatment with rivastigmine was well tolerated. CONCLUSIONS: With the results of this study, the need for an effective therapy in cognitively impaired MS patients is still required. Thus, intensive and continued clinical research is required to explore therapeutic options for cognitive deficits in MS patients.


Assuntos
Inibidores da Colinesterase/uso terapêutico , Transtornos Cognitivos/tratamento farmacológico , Esclerose Múltipla/complicações , Fenilcarbamatos/uso terapêutico , Adulto , Transtornos Cognitivos/etiologia , Método Duplo-Cego , Feminino , Humanos , Masculino , Rememoração Mental , Pessoa de Meia-Idade , Rivastigmina , Resultado do Tratamento
5.
Nutr Metab Cardiovasc Dis ; 23(8): 723-31, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22682975

RESUMO

BACKGROUND AND AIMS: Crown-like structures (CLS) are characteristic histopathology features of inflamed adipose tissues in obese mice and humans. In previous work, we suggested that these cells derived from macrophages primarily involved in the reabsorption of dead adipocytes. Here, we used a well-characterized transgenic mouse model in which the death of adipocytes in adult mice is inducible and highly synchronized. In this "FAT ATTAC" model, apoptosis is induced through forced dimerization of a caspase-8 fusion protein. METHODS AND RESULTS: 0, 0.5, 1, 2, 3 and 10 days post induction of adipocyte cell death, we analyzed mesenteric and epididymal adipose depots by histology, immunohistochemistry and electron microscopy. Upon induction of caspase-8 dimerization, numerous adipocytes lost immunoreactivity for perilipin, a marker for live adipocytes. In the same areas, we found adipocytes with hypertrophic mitochondria and signs of organelle degeneration. Neutrophils and lymphocytes were the main inflammatory cells present in the tissue, and the macrophages were predominantly Mac-2 negative. Over the course of ablation, Mac-2 positive macrophages substituted for Mac-2 negative macrophages, followed by CLS formation. All perilipin negative, dead adipocytes were surrounded by CLS structures. The time course of histopathology was similar in both fat pads studied, but occurred at earlier stages and was more gradual in mesenteric fat. CONCLUSION: Our data demonstrate that CLS formation results as a direct consequence of adipocyte death, and that infiltrating macrophages actively uptake remnant lipids of dead adipocytes. Upon induction of adipocyte apoptosis, inflammatory cells infiltrate adipose tissue initially consisting of neutrophils followed by macrophages that are involved in CLS formation.


Assuntos
Adipócitos/patologia , Tecido Adiposo/patologia , Apoptose , Lipodistrofia/patologia , Doença Aguda , Adipócitos/citologia , Adiponectina/sangue , Animais , Proteínas de Transporte/metabolismo , Caspase 8/metabolismo , Inflamação/patologia , Macrófagos/citologia , Masculino , Camundongos , Camundongos Obesos , Camundongos Transgênicos , Microscopia Eletrônica , Mitocôndrias/patologia , Neutrófilos/citologia , Perilipina-1 , Fosfoproteínas/metabolismo
6.
Diabetologia ; 55(9): 2319-26, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22688349

RESUMO

Adiponectin is an adipocyte-derived secretory protein that has been very widely studied over the past 15 years. A multitude of different functions have been attributed to this adipokine. It has been characterised in vitro at the level of tissue culture systems and in vivo through genetic manipulation of rodent models. It is also widely accepted as a biomarker in clinical studies. Originating in adipose tissue, generally positive metabolic effects have been attributed to adiponectin. In this review, we briefly discuss the key characteristics of this interesting but very complex molecule, highlight recent results in the context of its mechanism of action and summarise some of the key epidemiological data that helped establish adiponectin as a robust biomarker for insulin sensitivity, cardiovascular disease and many additional disease phenomena.


Assuntos
Adiponectina/metabolismo , Tecido Adiposo/metabolismo , Doenças Cardiovasculares/metabolismo , Inflamação/metabolismo , Resistência à Insulina , Receptores de Adiponectina/metabolismo , Adiponectina/genética , Animais , Biomarcadores/metabolismo , Doenças Cardiovasculares/genética , Regulação da Expressão Gênica/genética , Humanos , Inflamação/genética , Resistência à Insulina/genética , Receptores de Adiponectina/genética
7.
Diabetologia ; 54(10): 2515-24, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21779869

RESUMO

AIMS/HYPOTHESIS: Plasma levels of adiponectin are inversely associated with body mass. We hypothesised that adipose tissue distribution and body composition influences adiponectin levels. METHODS: We assessed plasma adiponectin concentrations and dual-energy X-ray absorptiometry (DEXA) measurements of body composition among 2,820 participants from the Dallas Heart Study. RESULTS: Among both women and men, adiponectin levels were higher in whites than in either Hispanics or African-Americans (for women: median 9.99 µg/ml [25th,75th percentile 7.11, 13.77] vs 7.56 µg/ml [5.05, 9.98] vs 6.39 µg/ml [4.37, 9.41], respectively, p < 0.0001; for men: 6.43 µg/ml [4.66, 9.19] vs 5.55 µg/ml [3.64, 7.50] vs 5.03 µg/ml [3.39, 7.28], p < 0.0001). In univariate analysis, each individual component of body mass was inversely associated with adiponectin. After multivariate analysis, adiponectin levels were found to be positively associated with lower extremity fat, whether expressed in absolute mass (for women: ß = 0.055, p < 0.0001; for men: ß = 0.061, p < 0.0001), or as a relative proportion (for women: ß = 0.035, p < 0.0001; for men: ß = 0.034, p < 0.0001). This association was consistent across ethnicities. Conversely, adiponectin was negatively correlated with truncal fat, both in absolute (for women: ß = -0.039, p < 0.0001; for men: ß = -0.044, p < 0.0001) and relative terms (for women: ß = -0.027, p < 0.0001; for men ß = -0.033, p < 0.0001). At the extreme of body mass, higher degrees of lower extremity and truncal adiposity were associated with higher levels of adiponectin. CONCLUSIONS/INTERPRETATION: These data suggest that the location of adipose depots differentially influences circulating adiponectin concentrations-a finding observed across ethnicity and sex. Gross measures of body mass alone do not adequately account for adiponectin levels. This supports a role of adiponectin as a mediator of the positive effects of lower extremity adiposity on improvements in insulin sensitivity.


Assuntos
Adiponectina/sangue , Tecido Adiposo/metabolismo , Absorciometria de Fóton , Adiposidade/fisiologia , Adulto , Composição Corporal/fisiologia , Índice de Massa Corporal , Peso Corporal/fisiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Obesidade/sangue , Obesidade/metabolismo , Adulto Jovem
8.
Nat Med ; 7(8): 947-53, 2001 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-11479628

RESUMO

Acrp30 is a circulating protein synthesized in adipose tissue. A single injection in mice of purified recombinant Acrp30 leads to a 2-3-fold elevation in circulating Acrp30 levels, which triggers a transient decrease in basal glucose levels. Similar treatment in ob/ob, NOD (non-obese diabetic) or streptozotocin-treated mice transiently abolishes hyperglycemia. This effect on glucose is not associated with an increase in insulin levels. Moreover, in isolated hepatocytes, Acrp30 increases the ability of sub-physiological levels of insulin to suppress glucose production. We thus propose that Acrp30 is a potent insulin enhancer linking adipose tissue and whole-body glucose metabolism.


Assuntos
Adipócitos/metabolismo , Proteínas Sanguíneas/fisiologia , Insulina/fisiologia , Peptídeos e Proteínas de Sinalização Intercelular , Fígado/fisiologia , Proteínas , Tiazolidinedionas , Adiponectina , Animais , Proteínas Sanguíneas/metabolismo , Linhagem Celular , Ingestão de Energia , Glucose/biossíntese , Humanos , Hipoglicemiantes/farmacologia , Camundongos , Camundongos Endogâmicos C57BL , Proteínas Recombinantes/metabolismo , Tiazóis/farmacologia
9.
Appl Environ Microbiol ; 76(6): 1842-50, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-20097828

RESUMO

Beet silage and beet juice were digested continuously as representative energy crops in a thermophilic biogas fermentor for more than 7 years. Fluorescence microscopy of 15 samples covering a period of 650 days revealed that a decrease in temperature from 60 degrees C to 55 degrees C converted a morphologically uniform archaeal population (rods) into a population of methanogens exhibiting different cellular morphologies (rods and coccoid cells). A subsequent temperature increase back to 60 degrees C reestablished the uniform morphology of methanogens observed in the previous 60 degrees C period. In order to verify these observations, representative samples were investigated by amplified rRNA gene restriction analysis (ARDRA) and fluorescence in situ hybridization (FISH). Both methods confirmed the temperature-dependent population shift observed by fluorescence microscopy. Moreover, all samples investigated demonstrated that hydrogenotrophic Methanobacteriales dominated in the fermentor, as 29 of 34 identified operational taxonomic units (OTUs) were assigned to this order. This apparent discrimination of acetoclastic methanogens contradicts common models for anaerobic digestion processes, such as anaerobic digestion model 1 (ADM1), which describes the acetotrophic Euryarchaeota as predominant organisms.


Assuntos
Archaea/crescimento & desenvolvimento , Bactérias/crescimento & desenvolvimento , Beta vulgaris/metabolismo , Reatores Biológicos/microbiologia , Metano/metabolismo , Silagem/microbiologia , Temperatura , Anaerobiose , Archaea/classificação , Archaea/metabolismo , Bactérias/classificação , Bactérias/metabolismo , Impressões Digitais de DNA , Hibridização in Situ Fluorescente , Metagenômica , Dados de Sequência Molecular , Análise de Sequência de DNA
10.
Trends Cell Biol ; 4(7): 231-5, 1994 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-14731661

RESUMO

Caveolae, 50-100 nm invaginations that represent a subcompartment of the plasma membrane, have been known for many years, but their exact roles remain uncertain. The findings that the caveolae coat protein caveolin is a v-Src substrate and that G-protein-coupled receptors are present in caveolae have suggested a relationship between caveolae, caveolin and transmembrane signalling. The recent isolation of caveolin-rich membrane domains in which caveolin exists as a hetero-oligomeric complex with integral membrane proteins and known cytoplasmic signalling molecules provides support for this hypothesis. Compartmentalization of certain signalling molecules within caveolae could allow efficient and rapid coupling of activated receptors to more than one effector system.

11.
J Cell Biol ; 127(5): 1233-43, 1994 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-7962086

RESUMO

Caveolae, also termed plasmalemmal vesicles, are small, flask-shaped, non-clathrin-coated invaginations of the plasma membrane. Caveolin is a principal component of the filaments that make up the striated coat of caveolae. Using caveolin as a marker protein for the organelle, we found that adipose tissue is the single most abundant source of caveolae identified thus far. Caveolin mRNA and protein are strongly induced during differentiation of 3T3-L1 fibroblasts to adipocytes; during adipogenesis there is also a dramatic increase in the complexity of the protein composition of caveolin-rich membrane domains. About 10-15% of the insulin-responsive glucose transporter GLUT4 is found in this caveolin-rich fraction, and immuno-isolated vesicles containing GLUT4 also contain caveolin. However, in non-stimulated adipocytes the majority of caveolin fractionates with the plasma membrane, while most GLUT4 associates with low-density microsomes. Upon addition of insulin to 3T3-L1 adipocytes, there is a significant increase in the amount of GLUT4 associated with caveolin-rich membrane domains, an increase in the amount of caveolin associated with the plasma membrane, and a decrease in the amount of caveolin associated with low-density microsomes. Caveolin does not undergo a change in phosphorylation upon stimulation of 3T3-L1 adipocytes with insulin. However, after treatment with insulin it is associated with a 32-kD phosphorylated protein. Caveolae thus may play an important role in the vesicular transport of GLUT4 to or from the plasma membrane. 3T3-L1 adipocytes offer an attractive system to study the function of caveolae in several cellular trafficking and signaling events.


Assuntos
Adipócitos/citologia , Caveolinas , Membrana Celular/metabolismo , Proteínas de Membrana/metabolismo , Proteínas de Transporte de Monossacarídeos/metabolismo , Proteínas Musculares , Células 3T3 , Adipócitos/metabolismo , Adipócitos/ultraestrutura , Tecido Adiposo/química , Animais , Transporte Biológico , Caveolina 1 , Diferenciação Celular , Membrana Celular/ultraestrutura , Endocitose , Transportador de Glucose Tipo 4 , Insulina/farmacologia , Proteínas de Membrana/análise , Proteínas de Membrana/biossíntese , Proteínas de Membrana/genética , Camundongos , Microscopia Eletrônica , Fosfoproteínas/metabolismo , Fosforilação , RNA Mensageiro/genética , RNA Mensageiro/metabolismo
12.
J Cell Biol ; 133(2): 257-68, 1996 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-8609160

RESUMO

We have identified and characterized Cab45, a novel 45-kD protein from mouse 3T3-L1 adipocytes. Cab45 is ubiquitously expressed, contains an NH2-terminal signal sequence but no membrane-anchor sequences, and binds Ca2+ due to the presence of six EF-hand motifs. Within the superfamily of calcium-binding proteins, it belongs to a recently identified group of proteins consisting of Reticulocalbin (Ozawa, M., and T. Muramatsu. 1993. J. Biol. Chem. 268:699-705) and ERC 55 (Weis, K., G. Griffiths, and A.I. Lamond. 1994. J. Biol Chem. 269:19142-19150), both of which share significant sequence homology with Cab45 outside the EF-hand motifs. In contrast to reticulocalbin and ERC-55 which are soluble components of the endoplasmic reticulum, Cab45 is a soluble protein localized to the Golgi. Cab45 is the first calcium-binding protein localized to the lumenal portion of a post-ER compartment; Cab45 is also the first known soluble protein resident in the Golgi lumen. Cab45 can serve as a model protein to determine the mechanism of retention of soluble proteins in the Golgi compartment.


Assuntos
Proteínas de Ligação ao Cálcio/análise , Glicoproteínas/análise , Complexo de Golgi/química , Células 3T3 , Adipócitos , Sequência de Aminoácidos , Animais , Sequência de Bases , Brefeldina A , Proteínas de Ligação ao Cálcio/química , Proteínas de Ligação ao Cálcio/genética , Proteínas de Ligação ao Cálcio/metabolismo , Clonagem Molecular , Ciclopentanos/farmacologia , DNA Complementar/genética , Expressão Gênica , Glicoproteínas/química , Glicoproteínas/genética , Glicoproteínas/metabolismo , Glicosilação , Camundongos , Dados de Sequência Molecular , Peso Molecular , Inibidores da Síntese de Proteínas/farmacologia , RNA Mensageiro/análise , Proteínas Recombinantes de Fusão/metabolismo , Análise de Sequência de DNA
13.
J Cell Biol ; 126(1): 111-26, 1994 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-7517942

RESUMO

Caveolae are 50-100-nm membrane microdomains that represent a subcompartment of the plasma membrane. Previous morphological studies have implicated caveolae in (a) the transcytosis of macromolecules (including LDL and modified LDLs) across capillary endothelial cells, (b) the uptake of small molecules via a process termed potocytosis involving GPI-linked receptor molecules and an unknown anion transport protein, (c) interactions with the actin-based cytoskeleton, and (d) the compartmentalization of certain signaling molecules, including G-protein coupled receptors. Caveolin, a 22-kD integral membrane protein, is an important structural component of caveolae that was first identified as a major v-Src substrate in Rous sarcoma virus transformed cells. This finding initially suggested a relationship between caveolin, transmembrane signaling, and cellular transformation. We have recently developed a procedure for isolating caveolin-rich membrane domains from cultured cells. To facilitate biochemical manipulations, we have applied this procedure to lung tissue--an endothelial and caveolin-rich source-allowing large scale preparation of these complexes. These membrane domains retain approximately 85% of caveolin and approximately 55% of a GPI-linked marker protein, while they exclude > or = 98% of integral plasma membrane protein markers and > or = 99.6% of other organelle-specific membrane markers tested. Characterization of these complexes by micro-sequencing and immuno-blotting reveals known receptors for modified forms of LDL (scavenger receptors: CD 36 and RAGE), multiple GPI-linked proteins, an anion transporter (plasma membrane porin), cytoskeletal elements, and cytoplasmic signaling molecules--including Src-like kinases, hetero-trimeric G-proteins, and three members of the Rap family of small GTPases (Rap 1--the Ras tumor suppressor protein, Rap 2, and TC21). At least a fraction of the actin in these complexes appeared monomeric (G-actin), suggesting that these domains could represent membrane bound sites for microfilament nucleation/assembly during signaling. Given that the majority of these proteins are known molecules, our current studies provide a systematic basis for evaluating these interactions in vivo.


Assuntos
Caveolinas , Endotélio Vascular/química , Membranas Intracelulares/química , Pulmão/química , Proteínas de Membrana/química , Sequência de Aminoácidos , Animais , Antígenos CD/análise , Antígenos CD36 , Caveolina 1 , Compartimento Celular , Transformação Celular Viral , Membranas Intracelulares/ultraestrutura , Camundongos , Dados de Sequência Molecular , Processamento de Proteína Pós-Traducional , Análise de Sequência , Transdução de Sinais , Frações Subcelulares/química , Distribuição Tecidual
14.
Biotechnol Bioeng ; 102(3): 736-48, 2009 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-18988261

RESUMO

A fuzzy logic control (FLC) system was developed at the Hamburg University of Applied Sciences (HAW Hamburg) for operation of biogas reactors running on energy crops. Three commercially available measuring parameters, namely pH, the methane (CH4) content, and the specific gas production rate (spec. GPR = m(3)/kg VS/day) were included. The objective was to avoid stabilization of pH with use of buffering supplements, like lime or manure. The developed FLC system can cover most of all applications, such as a careful start-up process and a gentle recovery strategy after a severe reactor failure, also enabling a process with a high organic loading rate (OLR) and a low hydraulic retention time (HRT), that is, a high throughput anaerobic digestion process with a stable pH and CH4 content. A precondition for a high load process was the concept of interval feeding, for example, with 8 h of interval. The FLC system was proved to be reliable during the long term fermentation studies over 3 years in one-stage, completely stirred tank reactors (CSTR) with acidic beet silage as mono-input (pH 3.3-3.4). During fermentation of the fodder beet silage (FBS), a stable HRT of 6.0 days with an OLR of up to 15 kg VS/m(3)/day and a volumetric GPR of 9 m(3)/m(3)/day could be reached. The FLC enabled an automatic recovery of the digester after two induced severe reactor failures. In another attempt to prove the feasibility of the FLC, substrate FBS was changed to sugar beet silage (SBS), which had a substantially lower buffering capacity than that of the FBS. With SBS, the FLC accomplished a stable fermentation at a pH level between 6.5 and 6.6, and a volatile fatty acid level (VFA) below 500 mg/L, but the FLC had to interact and to change the substrate dosage permanently. In a further experiment, the reactor temperature was increased from 41 to 50 degrees C. Concomitantly, the specific GPR, pH and CH4 dropped down. Finally, the FLC automatically enabled a complete recovery in 16 days.


Assuntos
Bactérias Anaeróbias/metabolismo , Processamento Eletrônico de Dados/métodos , Fontes Geradoras de Energia , Lógica Fuzzy , Silagem , Beta vulgaris/metabolismo , Biomassa , Reatores Biológicos , Soluções Tampão , Produtos Agrícolas/metabolismo , Ácidos Graxos Voláteis/metabolismo , Gases/análise , Concentração de Íons de Hidrogênio , Metano/análise , Temperatura
15.
Science ; 208(4439): 69-71, 1980 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-7361109

RESUMO

A new transport mechanism explains the importance of the shape of bronchial bifurcations in the transfer of gases and particles between the atmosphere and the alveoli. Photographs of flow visualization experiments illustrate the effect in models of bronchial branching. The mechanism provides a means of nondiffusional transport that helps to explain normal respiratory exchange of gases as well as successful ventilation with very low tidal volumes, as in some lung diseases and in the high-frequency panting of dogs.


Assuntos
Brônquios/anatomia & histologia , Respiração , Animais , Brônquios/fisiologia , Humanos , Volume de Ventilação Pulmonar
17.
Int J Obes (Lond) ; 32(5): 740-8, 2008 May.
Artigo em Inglês | MEDLINE | ID: mdl-18180784

RESUMO

BACKGROUND: There are limited data concerning the relationships between changes in adipocytokines and cardiovascular disease (CVD) risk factors. OBJECTIVE: To examine the longitudinal associations between leptin, adiponectin, resistin and ghrelin levels and CVD risk factor levels in women at midlife. DESIGN: Prospective, observational study. SUBJECTS AND MEASUREMENTS: Leptin, adiponectin, resistin, ghrelin levels and CVD risk factors were measured in specimens collected from 40 women at 3 points in time corresponding to the pre-, peri- and postmenopause stages of their natural menopause transition. RESULTS: In longitudinal analyses adjusted for CVD risk factors and leptin at the previous menopausal stage, aging, education, smoking and physical activity, greater increases in leptin over the menopause transition were associated with greater decreases in high-density lipoprotein cholesterol (HDL-c) and greater increases in diastolic blood pressure, glucose, insulin and insulin resistance (all P < 0.05). Larger decreases in adiponectin over the menopause transition were associated with greater increases in systolic blood pressure, insulin and insulin resistance and with greater decreases in HDL-c. Greater increases in ghrelin levels over the menopausal transition were associated with greater low-density lipoprotein cholesterol increases (P = 0.014). Resistin was not associated with CVD risk factor changes. CONCLUSION: There were significant adverse associations of adipocytokines and ghrelin with multiple CVD risk factor changes in women across midlife. Given that this time period is dynamic for CVD risk, these data underscore the need for additional prospective studies.


Assuntos
Adipocinas/sangue , Doenças Cardiovasculares , Grelina/sangue , Menopausa/sangue , Adiponectina/sangue , Adulto , Biomarcadores/sangue , Pesos e Medidas Corporais , Doenças Cardiovasculares/etiologia , Feminino , Humanos , Estudos Longitudinais , Pessoa de Meia-Idade , Resistina/sangue , Fatores de Risco
19.
Curr Biol ; 8(6): 335-8, 1998 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-9512423

RESUMO

ACRP30--adipocyte complement-related protein of 30 kDa or AdipoQ--is an abundant serum protein, secreted exclusively from fat cells, which is implicated in energy homeostasis and obesity [1,2]. ACRP30 is a close homologue of the complement protein C1q, which is involved in the recognition of microbial surfaces [3-5] and antibody-antigen complexes [6,7] in the classical pathway of complement. We have determined the crystal structure of a homotrimeric fragment from ACRP30 at 2.1 A resolution. The structure reveals an unexpected homology to the tumor necrosis factor (TNF) family. Identical folding topologies, key residue conservations, and similarity of trimer interfaces and intron positions firmly establish an evolutionary link between the TNF and C1q families. We suggest that TNFs--which control many aspects of inflammation, adaptive immunity, apoptosis and energy homeostasis--arose by divergence from a primordial recognition molecule of the innate immune system. The evolutionary connection between C1q-like proteins and TNFs illuminates the shared functions of these two important groups of proteins.


Assuntos
Complemento C1q/química , Fator de Necrose Tumoral alfa/química , Evolução Molecular , Modelos Estruturais , Conformação Proteica , Estrutura Terciária de Proteína , Alinhamento de Sequência
20.
J Clin Invest ; 108(12): 1875-81, 2001 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11748271

RESUMO

Intraperitoneal injection of purified recombinant Acrp30 lowers glucose levels in mice. To gain insight into the mechanism(s) of this hypoglycemic effect, purified recombinant Acrp30 was infused in conscious mice during a pancreatic euglycemic clamp. In the presence of physiological hyperinsulinemia, this treatment increased circulating Acrp30 levels by approximately twofold and stimulated glucose metabolism. The effect of Acrp30 on in vivo insulin action was completely accounted for by a 65% reduction in the rate of glucose production. Similarly, glucose flux through glucose-6-phosphatase (G6Pase) decreased with Acrp30, whereas the activity of the direct pathway of glucose-6-phosphate biosynthesis, an index of hepatic glucose phosphorylation, increased significantly. Acrp30 did not affect the rates of glucose uptake, glycolysis, or glycogen synthesis. These results indicate that an acute increase in circulating Acrp30 levels lowers hepatic glucose production without affecting peripheral glucose uptake. Hepatic expression of the gluconeogenic enzymes phosphoenolpyruvate carboxykinase and G6Pase mRNAs was reduced by more than 50% following Acrp30 infusion compared with vehicle infusion. Thus, a moderate rise in circulating levels of the adipose-derived protein Acrp30 inhibits both the expression of hepatic gluconeogenic enzymes and the rate of endogenous glucose production.


Assuntos
Proteínas Sanguíneas/fisiologia , Glucose/biossíntese , Peptídeos e Proteínas de Sinalização Intercelular , Proteínas , Adiponectina , Animais , Gluconeogênese , Glucose-6-Fosfatase/genética , Hiperinsulinismo/metabolismo , Fígado/metabolismo , Masculino , Camundongos , Fosfoenolpiruvato Carboxiquinase (ATP)/genética , RNA Mensageiro/análise , Proteínas Recombinantes/farmacologia
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