Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 1.076
Filtrar
1.
Bipolar Disord ; 21(4): 330-341, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30864200

RESUMO

OBJECTIVES: To investigate neurochemical abnormalities in the left and right ventrolateral prefrontal cortex (VLPFC) and anterior cingulate cortex (ACC) of youth at risk for bipolar disorder using proton magnetic resonance spectroscopy before and after their first mood episode. METHODS: Children and adolescents offspring of parents with bipolar I disorder (at-risk group, n = 117) and matched healthy controls (HC group, n = 61) were recruited at the University of Cincinnati. At-risk subjects had no lifetime major mood and psychotic disorders at baseline, and were followed up every 4 months to monitor for development of a major depressive, manic, hypomanic, or mixed mood episode. Levels of N-acetyl-aspartate (NAA), phosphocreatine plus creatine (PCr + Cr), choline-containing compounds, myo-inositol, and glutamate were determined using LCModel and corrected for partial volume effects. RESULTS: There were no baseline differences in metabolite levels for any of the brain regions between at-risk and HC youth. Nineteen at-risk subjects developed a first mood episode during follow-up. Survival analyses showed that baseline PCr + Cr levels in the left VLPFC significantly predicted a mood episode during follow-up in the at-risk group (HR: 0.47, 95% CI: 0.27-0.82, P = 0.008). There were no longitudinal changes in metabolites levels in the VLPFC and ACC before and after a mood episode in at-risk subjects. CONCLUSIONS: We found no evidence for abnormal proton spectroscopy metabolite levels in the VLPFC and ACC of at-risk youth, prior and after the development of their first mood episode. Preliminary findings of association between baseline PCr + Cr levels in the left VLPFC and risk to develop a mood episode warrant further investigation.


Assuntos
Sintomas Afetivos , Transtorno Bipolar , Filho de Pais Incapacitados/psicologia , Creatina/análise , Giro do Cíngulo/metabolismo , Fosfocreatina/análise , Córtex Pré-Frontal/metabolismo , Medição de Risco , Adolescente , Adulto , Sintomas Afetivos/diagnóstico , Sintomas Afetivos/metabolismo , Transtorno Bipolar/diagnóstico , Transtorno Bipolar/metabolismo , Criança , Creatina/metabolismo , Feminino , Humanos , Estudos Longitudinais , Masculino , Espectroscopia de Prótons por Ressonância Magnética/métodos , Medição de Risco/métodos
2.
Nutrients ; 11(1)2019 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-30621358

RESUMO

Type 2 diabetic women have a high risk of mortality via myocardial infarction even with anti-diabetic treatments. Resveratrol (RSV) is a natural polyphenol, well-known for its antioxidant property, which has also shown interesting positive effects on mitochondrial function. Therefore, we aim to investigate the potential protective effect of 1 mg/kg/day of RSV on high energy compounds, during myocardial ischemia-reperfusion in type 2 diabetic female Goto-Kakizaki (GK) rats. For this purpose, we used 31P magnetic resonance spectroscopy in isolated perfused heart experiments, with a simultaneous measurement of myocardial function and coronary flow. RSV enhanced adenosine triphosphate (ATP) and phosphocreatine (PCr) contents in type 2 diabetic hearts during reperfusion, in combination with better functional recovery. Complementary biochemical analyses showed that RSV increased creatine, total adenine nucleotide heart contents and citrate synthase activity, which could be involved in better mitochondrial functioning. Moreover, improved coronary flow during reperfusion by RSV was associated with increased eNOS, SIRT1, and P-Akt protein expression in GK rat hearts. In conclusion, RSV induced cardioprotection against ischemia-reperfusion injury in type 2 diabetic female rats via increased high energy compound contents and expression of protein involved in NO pathway. Thus, RSV presents high potential to protect the heart of type 2 diabetic women from myocardial infarction.


Assuntos
Diabetes Mellitus Tipo 2/complicações , Metabolismo Energético/efeitos dos fármacos , Traumatismo por Reperfusão Miocárdica/prevenção & controle , Óxido Nítrico Sintase Tipo III/genética , Resveratrol/administração & dosagem , Sirtuína 1/genética , Trifosfato de Adenosina/análise , Animais , Cardiotônicos , Cardiomiopatias Diabéticas/prevenção & controle , Feminino , Expressão Gênica/efeitos dos fármacos , Espectroscopia de Ressonância Magnética , Infarto do Miocárdio/prevenção & controle , Traumatismo por Reperfusão Miocárdica/genética , Miocárdio/química , Óxido Nítrico/metabolismo , Fosfocreatina/análise , Ratos , Ratos Wistar
3.
Magn Reson Med ; 81(1): 69-78, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30246265

RESUMO

PURPOSE: To obtain high-resolution Cr and PCr maps of mouse skeletal muscle using a polynomial and Lorentzian line-shape fitting (PLOF) CEST method. METHODS: Wild-type mice and guanidinoacetate N-methyltransferase-deficient (GAMT-/-) mice that have low Cr and PCr concentrations in muscle were used to assign the Cr and PCr peaks in the Z-spectrum at 11.7 T. A PLOF method was proposed to simultaneously extract and quantify the Cr and PCr by assuming a polynomial function for the background and 2 Lorentzian functions for the CEST peaks at 1.95 ppm and 2.5 ppm. RESULTS: The Z-spectra of phantoms revealed that PCr has 2 CEST peaks (2 ppm and 2.5 ppm), whereas Cr only showed 1 peak at 2 ppm. Comparison of the Z-spectra of wild-type and GAMT-/- mice indicated that, contrary to brain, there was no visible protein guanidinium peak in the skeletal-muscle Z-spectrum, which allowed us to extract clean PCr and Cr CEST signals. High-resolution PCr and Cr concentration maps of mouse skeletal muscle were obtained by the PLOF CEST method after calibration with in vivo MRS. CONCLUSIONS: The PLOF method provides an efficient way to map Cr and PCr concentrations simultaneously in the skeletal muscle at high MRI field.


Assuntos
Creatina/análise , Espectroscopia de Ressonância Magnética/métodos , Músculo Esquelético/metabolismo , Fosfocreatina/análise , Algoritmos , Animais , Meios de Contraste , Feminino , Guanidinoacetato N-Metiltransferase/genética , Guanidinoacetato N-Metiltransferase/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Modelos Teóricos , Imagens de Fantasmas , Fosfocreatina/análogos & derivados , Fosfocreatina/sangue
4.
J Strength Cond Res ; 33(1): 36-43, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28445224

RESUMO

Kasai, N, Mizuno, S, Ishimoto, S, Sakamoto, E, Maruta, M, Kurihara, T, Kurosawa, Y, and Goto, K. Impact of six consecutive days of sprint training in hypoxia on performance in competitive sprint runners. J Strength Cond Res 33(1): 36-43, 2019-The purpose of this study was to determine the effects of 6 successive days of repeated sprint (RS) training in moderate hypoxia on anaerobic capacity in 100-200-m sprint runners. Eighteen male sprint runners (age, 20.0 ± 0.3 years; height, 175.9 ± 1.1 cm; and body mass, 65.0 ± 1.2 kg) performed repeated cycling sprints for 6 consecutive days in either normoxic (NOR; fraction of inspired oxygen [FiO2], 20.9%; n = 9) or hypoxic conditions (HYPO; FiO2, 14.5%; n = 9). The RS ability (10 × 6-second sprints), 30-second maximal sprint ability, maximal oxygen uptake ((Equation is included in full-text article.)max), and 60-m running time on the track were measured before and after the training period. Intramuscular phosphocreatine (PCr) content (quadriceps femoris muscle) was measured by P-magnetic resonance spectroscopy (P-MRS) before and after the training period. Both groups showed similar improvements in RS ability after the training period (p < 0.05). Power output during the 30-second maximal sprint test and (Equation is included in full-text article.)max did not change significantly after the training period in either group. Running time for 0-10 m improved significantly after the training period in the HYPO only (before, 1.39 ± 0.01 seconds; after, 1.34 ± 0.02 seconds, p < 0.05). The HYPO also showed a significant increase in intramuscular PCr content after the training period (before, 31.5 ± 1.3 mM; after, 38.2 ± 2.8 mM, p < 0.05). These results suggest that sprint training for 6 consecutive days in hypoxia or normoxia improved RS ability in competitive sprint runners.


Assuntos
Desempenho Atlético , Hipóxia , Condicionamento Físico Humano , Corrida/fisiologia , Atletas , Humanos , Masculino , Fosfocreatina/análise , Músculo Quadríceps/química , Adulto Jovem
5.
J Affect Disord ; 235: 15-19, 2018 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-29631202

RESUMO

BACKGROUND: Despite the diagnostic challenges in categorizing bipolar disorder subtypes, bipolar I and II disorders (BD-I and BD-II respectively) are valid indices for researchers. Subtle neurobiological differences may underlie clinical differences between mood disorder subtypes. The aims of this study were to investigate neurochemical differences between bipolar disorder subtypes. METHODS: Euthymic BD-II patients (n = 21) are compared with BD-I (n = 28) and healthy comparison subjects (HCs, n = 30). Magnetic Resonance Imaging (MRI) and proton spectroscopy (1H MRS) were performed on a 3T Siemens Tim Trio system. MRS voxels were located in the left/right superior temporal cortices, and spectra acquired with the single voxel Point REsolved Spectroscopy Sequence (PRESS). The spectroscopic data were analyzed with LCModel (Version 6.3.0) software. RESULTS: There were significant differences between groups in terms of glutamate [F = 6.27, p = 0.003], glutamate + glutamine [F = 6.08, p = 0.004], inositol containing compounds (Ino) (F = 9.25, p < 0.001), NAA [F = 7.63, p = 0.001] and creatine + phosphocreatine [F = 11.06, p < 0.001] in the left hemisphere and Ino [F = 5.65, p = 0.005] in the right hemisphere. Post-hoc comparisons showed that the BD-I disorder group had significantly lower metabolite levels in comparison to the BD-II and the HC groups. LIMITATIONS: This was a cross-sectional study with a small sample size. In addition, patients were on various psychotropic medications, which may have impacted the results. CONCLUSIONS: Neurochemical levels, in the superior temporal cortices, measured with 1H-MRS discriminated between BD-II and BD-I. Although further studies are needed, one may speculate that the superior temporal cortices (particularly left hemispheric) play a critical role, whose pathology may be related to subtyping bipolar disorder.


Assuntos
Transtorno Bipolar/metabolismo , Transtorno Ciclotímico/metabolismo , Imagem por Ressonância Magnética/métodos , Espectroscopia de Prótons por Ressonância Magnética/métodos , Lobo Temporal/metabolismo , Adulto , Transtorno Bipolar/diagnóstico por imagem , Creatina/análise , Estudos Transversais , Transtorno Ciclotímico/diagnóstico por imagem , Feminino , Ácido Glutâmico/análise , Humanos , Masculino , Fosfocreatina/análise , Lobo Temporal/diagnóstico por imagem , Adulto Jovem
6.
Magn Reson Med ; 79(2): 974-980, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-28560829

RESUMO

PURPOSE: To develop a high temporal resolution imaging method that measures muscle-specific phosphocreatine (PCr) resynthesis time constant (τPCr ) and pH changes in muscles of the lower leg following exercise on a clinical 3T MRI scanner. METHODS: We developed a frequency-selective 3D non-Cartesian FLORET sequence to measure PCr with 17-mm nominal isotropic resolution (28 mm actual resolution) and 6-s temporal resolution to capture dynamic metabolic muscle activity. The sequence was designed to additionally collect inorganic phosphate spectra for pH quantification, which were localized using sensitivity profiles of individual coil elements. Nineteen healthy volunteers were scanned while performing a plantar flexion exercise on an in-house developed ergometer. Data were acquired with a dual-tuned multichannel coil array that enabled phosphorus imaging and proton localization for muscle segmentation. RESULTS: After a 90-s plantar flexion exercise at 0.66 Hz with resistance set to 40% of the maximum voluntary contraction, τPCr was estimated at 22.9 ± 8.8 s (mean ± standard deviation) with statistical coefficient of determination r2 = 0.89 ± 0.05. The corresponding pH values after exercise were in the range of 6.9-7.1 in the gastrocnemius muscle. CONCLUSION: The developed technique allows measurement of muscle-specific PCr resynthesis kinetics and pH changes following exercise, with a temporal resolution and accuracy comparable to that of single voxel 31 P-MRS sequences. Magn Reson Med 79:974-980, 2018. © 2017 International Society for Magnetic Resonance in Medicine.


Assuntos
Exercício/fisiologia , Imagem Tridimensional/métodos , Imagem por Ressonância Magnética/métodos , Músculo Esquelético/diagnóstico por imagem , Fosfocreatina/análise , Adulto , Humanos , Concentração de Íons de Hidrogênio , Músculo Esquelético/fisiologia , Fosfocreatina/química , Fosfocreatina/metabolismo , Isótopos de Fósforo , Adulto Jovem
7.
Neonatology ; 113(1): 37-43, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29024930

RESUMO

BACKGROUND: Hypoxia-ischemia (HI) results in increased activation of Ca2+/calmodulin kinase IV (CaM kinase IV) mediated by Src kinase. Therapeutic hypothermia ameliorates neuronal injury in the newborn. HYPOTHESIS: Inhibition of Src kinase concurrently with hypothermia further attenuates the hypoxia-induced increased activation of CaM kinase IV compared with hypothermia alone. DESIGN/METHODS: Ventilated piglets were exposed to HI, received saline or a selective Src kinase inhibitor (PP2), and were cooled to 33°C. Neuropathology, adenosine triphosphate (ATP) and phosphocreatine (PCr) concentrations, and CaM kinase IV activity were determined. RESULTS: The neuropathology mean score (mean ± SD) was 0.4 ± 0.43 in normoxia-normothermia (p < 0.05 vs. hypoxia-normothermia), 3.5 ± 0.89 in hypoxia-normothermia (p < 0.05 vs. normoxia-normothermia), 0.7 ± 0.73 in hypoxia-hypothermia (p < 0.05 vs. normoxia-normothermia), and 0.5 ± 0.70 in normoxia-hypothermia (p < 0.05 vs. hypoxia-normothermia). The CaM kinase IV activity in cerebral tissue (pmol Pi/mg protein/min; mean ± SD) was 2,002 ± 729 in normoxia-normothermia, 1,704 ± 18 in normoxia-hypothermia, 6,017 ± 2,510 in hypoxia-normothermia, 4,104 ± 542 in hypoxia-hypothermia (p < 0.05 vs. normoxia-hypothermia), and 2,165 ± 415 in hypoxia-hypothermia with PP2 (p < 0.05 vs. hypoxia-hypothermia). The hypoxic groups with and without hypothermia or Src kinase inhibitor were comparable in the levels of ATP and PCr, indicating that they were similar in their degree of energy failure prior to treatments. Hypothermia or Src kinase inhibitor (PP2) did not restore the ATP and PCr levels. CONCLUSIONS: Hypothermia and Src kinase inhibition attenuated apoptotic cell death and improved neuropathology after hypoxia. The combination of short-duration hypothermia with Src kinase inhibition following hypoxia further attenuates the increased activation of CaM kinase IV compared to hypothermia alone in the newborn swine brain.


Assuntos
Encéfalo/patologia , Proteína Quinase Tipo 4 Dependente de Cálcio-Calmodulina/metabolismo , Hipotermia Induzida/métodos , Hipóxia Encefálica/metabolismo , Neurônios/patologia , Quinases da Família src/metabolismo , Trifosfato de Adenosina/análise , Animais , Animais Recém-Nascidos , Hipóxia Encefálica/patologia , Hipóxia Encefálica/terapia , Hipóxia-Isquemia Encefálica/metabolismo , Masculino , Fosfocreatina/análise , Suínos
8.
NMR Biomed ; 30(11)2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28915314

RESUMO

Proton magnetic resonance spectroscopy (1 H-MRS) can be used to quantify in vivo metabolite levels, such as lactate, γ-aminobutyric acid (GABA) and glutamate (Glu). However, there are considerable analysis choices which can alter the accuracy or precision of 1 H-MRS metabolite quantification. It is currently unknown to what extent variations in the analysis pipeline used to quantify 1 H-MRS data affect outcomes. The purpose of this study was to evaluate whether the quantification of identical 1 H-MRS scans across independent and experienced research groups would yield comparable results. We investigated the influence of model parameters and spectral quantification software on fitted metabolite concentration values. Sixty spectra in 30 individuals (repeated measures) were acquired using a 7-T MRI scanner. Data were processed by four independent research groups with the freedom to choose their own individualized and optimal parameter settings using LCModel software. Data were processed a second time in one group using an independent software package (NMRWizard) for an additional comparison with a different post-processing platform. Correlations across research groups of the ratio between the highest and, arguably, the most relevant resonances for neurotransmission [N-acetyl aspartate (NAA), N-acetyl aspartyl glutamate (NAAG) and Glu] over the total creatine [creatine (Cr) + phosphocreatine (PCr)] concentration, using Pearson's product-moment correlation coefficient (r), were calculated. Mean inter-group correlations using LCModel software were 0.87, 0.88 and 0.77 for NAA/Cr + PCr, NAA + NAAG/Cr + PCr and Glu/Cr + PCr, respectively. The mean correlations when comparing NMRWizard results with LCModel fitting results at University Medical Center Utrecht (UMCU) were 0.87, 0.89 and 0.71 for NAA/Cr + PCr, NAA + NAAG/Cr + PCr and Glu/Cr + PCr, respectively. Metabolite quantification using identical 1 H-MRS data was influenced by processing parameters, basis sets and software choice. Locally preferred processing choices affected metabolite quantification, even when using identical software. Our results reinforce the notion that standard practices should be established to regularize outcomes of 1 H-MRS studies, and that basis sets used for processing should be made available to the scientific community.


Assuntos
Espectroscopia de Ressonância Magnética/métodos , Ácido Aspártico/análogos & derivados , Ácido Aspártico/análise , Creatina/análise , Ácido Glutâmico/análise , Humanos , Fosfocreatina/análise
9.
Artigo em Inglês | MEDLINE | ID: mdl-28477512

RESUMO

The main purpose of this study was the determination and comparison of anomalies in creatine (Cr) accumulation occurring within CA3 and DG areas of hippocampal formation as a result of two high-fat, carbohydrate-restricted ketogenic diets (KD) with different ketogenic ratio (KR). To reach this goal, Fourier transformed infrared microspectroscopy with synchrotron radiation source (SRFTIR microspectroscopy) was applied for chemical mapping of creatine absorption bands, occurring around 1304, 1398 and 2800 cm-1. The samples were taken from three groups of experimental animals: control group (N) fed with standard laboratory diet, KD1 and KD2 groups fed with high-fat diets with KR 5:1 and 9:1 respectively. Additionally, the possible influence on the phosphocreatine (PhCr, the high energetic form of creatine) content was evaluated by comparative analysis of chemical maps obtained for creatine and for compounds containing phosphate groups which manifest in the spectra at the wavenumbers of around 1240 and 1080 cm-1. Our results showed that KD2 strongly modifies the frequency of Cr inclusions in both analyzed hippocampal areas. Statistical analysis, performed with Mann-Whitney U test revealed increased accumulation of Cr within CA3 and DG areas of KD2 fed rats compared to both normal rats and KD1 experimental group. Moreover, KD2 diet may modify the frequency of PhCr deposits as well as the PhCr to Cr ratio.


Assuntos
Creatina/análise , Dieta Hiperlipídica , Dieta Cetogênica , Hipocampo/química , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Animais , Creatina/metabolismo , Hipocampo/metabolismo , Masculino , Fosfocreatina/análise , Fosfocreatina/metabolismo , Ratos , Ratos Wistar , Síncrotrons
10.
Artigo em Inglês | MEDLINE | ID: mdl-27747196

RESUMO

Seizures and neurologic involvement have been reported in patients infected with Shiga toxin (Stx) producing E. coli, and hemolytic uremic syndrome (HUS) with neurologic involvement is associated with more severe outcome. We investigated the extent of renal and neurologic damage in mice following injection of the highly potent form of Stx, Stx2a, and less potent Stx1. As observed in previous studies, Stx2a brought about moderate to acute tubular necrosis of proximal and distal tubules in the kidneys. Brain sections stained with hematoxylin and eosin (H&E) appeared normal, although some red blood cell congestion was observed. Microglial cell responses to neural injury include up-regulation of surface-marker expression (e.g., Iba1) and stereotypical morphological changes. Mice injected with Stx2a showed increased Iba1 staining, mild morphological changes associated with microglial activation (thickening of processes), and increased microglial staining per unit area. Microglial changes were observed in the cortex, hippocampus, and amygdala regions, but not the nucleus. Magnetic resonance imaging (MRI) of Stx2a-treated mice revealed no hyper-intensities in the brain, although magnetic resonance spectroscopy (MRS) revealed significantly decreased levels of phosphocreatine in the thalamus. Less dramatic changes were observed following Stx1 challenge. Neither immortalized microvascular endothelial cells from the cerebral cortex of mice (bEnd.3) nor primary human brain microvascular endothelial cells were found to be susceptible to Stx1 or Stx2a. The lack of susceptibility to Stx for both cell types correlated with an absence of receptor expression. These studies indicate Stx causes subtle, but identifiable changes in the mouse brain.


Assuntos
Modelos Animais de Doenças , Sistema Nervoso/efeitos dos fármacos , Sistema Nervoso/patologia , Toxina Shiga/toxicidade , Tonsila do Cerebelo/efeitos dos fármacos , Tonsila do Cerebelo/patologia , Animais , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Encéfalo/patologia , Proteínas de Ligação ao Cálcio , Técnicas de Cultura de Células , Córtex Cerebral/efeitos dos fármacos , Córtex Cerebral/patologia , Proteínas de Ligação a DNA , Células Endoteliais/efeitos dos fármacos , Células Endoteliais/patologia , Eritrócitos/efeitos dos fármacos , Escherichia coli/metabolismo , Escherichia coli/patogenicidade , Síndrome Hemolítico-Urêmica/microbiologia , Síndrome Hemolítico-Urêmica/patologia , Hipocampo/efeitos dos fármacos , Hipocampo/patologia , Humanos , Rim/efeitos dos fármacos , Rim/patologia , Imagem por Ressonância Magnética/métodos , Masculino , Camundongos , Proteínas dos Microfilamentos , Microglia/efeitos dos fármacos , Microglia/patologia , Fosfocreatina/análise , Coelhos , Proteínas Repressoras , Toxina Shiga/administração & dosagem , Toxina Shiga II/administração & dosagem , Toxina Shiga II/toxicidade , Análise Espectral/métodos , Tálamo/química , Testes de Toxicidade/métodos , Fator de Necrose Tumoral alfa/farmacologia , Ganho de Peso/efeitos dos fármacos , Perda de Peso/efeitos dos fármacos
11.
Sci Rep ; 6: 30568, 2016 07 28.
Artigo em Inglês | MEDLINE | ID: mdl-27465636

RESUMO

Magnetic resonance imaging (MRI) provides the unique ability to study metabolic and microvasculature functions in skeletal muscle using phosphorus and proton measurements. However, the low sensitivity of these techniques can make it difficult to capture dynamic muscle activity due to the temporal resolution required for kinetic measurements during and after exercise tasks. Here, we report the design of a dual-nuclei coil array that enables proton and phosphorus MRI of the human lower extremities with high spatial and temporal resolution. We developed an array with whole-volume coverage of the calf and a phosphorus signal-to-noise ratio of more than double that of a birdcage coil in the gastrocnemius muscles. This enabled the local assessment of phosphocreatine recovery kinetics following a plantar flexion exercise using an efficient sampling scheme with a 6 s temporal resolution. The integrated proton array demonstrated image quality approximately equal to that of a clinical state-of-the-art knee coil, which enabled fat quantification and dynamic blood oxygen level-dependent measurements that reflect microvasculature function. The developed array and time-efficient pulse sequences were combined to create a localized assessment of calf metabolism using phosphorus measurements and vasculature function using proton measurements, which could provide new insights into muscle function.


Assuntos
Imagem por Ressonância Magnética/instrumentação , Imagem por Ressonância Magnética/métodos , Músculo Esquelético/fisiologia , Fosfocreatina/análise , Adulto , Desenho de Equipamento , Humanos , Contração Isométrica/fisiologia , Cinética , Masculino , Músculo Esquelético/metabolismo , Fosfocreatina/metabolismo , Razão Sinal-Ruído
12.
MAGMA ; 29(3): 491-501, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27059982

RESUMO

OBJECTIVE: To demonstrate that high resolution (1)H semi-LASER MRSI acquired at 7 T permits discrimination of metabolic patterns of different thalamic nuclei. MATERIALS AND METHODS: Thirteen right-handed healthy volunteers were explored at 7 T using a high-resolution 2D-semi-LASER (1)H-MRSI sequence to determine the relative levels of N-Acetyl Aspartate (NAA), choline (Cho) and creatine-phosphocreatine (Cr) in eight VOIs (volume <0.3 ml) centered on four different thalamic nuclei located on the Oxford thalamic connectivity atlas. Post-processing was done using the CSIAPO software. Chemical shift displacement of metabolites was evaluated on a phantom and correction factors were applied to in vivo data. RESULTS: The global assessment (ANOVA p < 0.05) of the neurochemical profiles (NAA, Cho and Cr levels) with thalamic nuclei and hemispheres as factors showed a significant global effect (F = 11.98, p < 0.0001), with significant effect of nucleus type (p < 0.0001) and hemisphere (p < 0.0001). Post hoc analyses showed differences in neurochemical profiles between the left and the right hemisphere (p < 0.05), and differences in neurochemical profiles between nuclei within each hemisphere (p < 0.05). CONCLUSION: For the first time, using high resolution 2D-PRESS semi-LASER (1)H-MRSI acquired at 7 T, we demonstrated that the neurochemical profiles were different between thalamic nuclei, and that these profiles were dependent on the brain hemisphere.


Assuntos
Imagem por Ressonância Magnética , Espectroscopia de Ressonância Magnética , Tálamo/diagnóstico por imagem , Adulto , Análise de Variância , Ácido Aspártico/análogos & derivados , Ácido Aspártico/análise , Encéfalo/diagnóstico por imagem , Colina/análise , Creatina/análise , Feminino , Voluntários Saudáveis , Humanos , Lasers , Masculino , Doenças Neurodegenerativas/diagnóstico por imagem , Imagens de Fantasmas , Fosfocreatina/análogos & derivados , Fosfocreatina/análise , Software , Espectrofotometria , Tálamo/metabolismo , Adulto Jovem
13.
Adv Exp Med Biol ; 876: 49-54, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26782194

RESUMO

Previous studies have reported significant region-dependent differences in the fiber-type composition of human skeletal muscle. It is therefore hypothesized that there is a difference between the deep and superficial parts of muscle energy metabolism during exercise. We hypothesized that the inorganic phosphate (Pi)/phosphocreatine (PCr) ratio of the superficial parts would be higher, compared with the deep parts, as the work rate increases, because the muscle fiber-type composition of the fast-type may be greater in the superficial parts compared with the deep parts. This study used two-dimensional 31Phosphorus Chemical Shift Imaging (31P-CSI) to detect differences between the deep and superficial parts of the human leg muscles during dynamic knee extension exercise. Six healthy men participated in this study (age 27±1 year, height 169.4±4.1 cm, weight 65.9±8.4 kg). The experiments were carried out with a 1.5-T superconducting magnet with a 5-in. diameter circular surface coil. The subjects performed dynamic one-legged knee extension exercise in the prone position, with the transmit-receive coil placed under the right quadriceps muscles in the magnet. The subjects pulled down an elastic rubber band attached to the ankle at a frequency of 0.25, 0.5 and 1 Hz for 320 s each. The intracellular pH (pHi) was calculated from the median chemical shift of the Pi peak relative to PCr. No significant difference in Pi/PCr was observed between the deep and the superficial parts of the quadriceps muscles at rest. The Pi/PCr of the superficial parts was not significantly increased with increasing work rate. Compared with the superficial areas, the Pi/PCr of the deep parts was significantly higher (p<0.05) at 1 Hz. The pHi showed no significant difference between the two parts. These results suggest that muscle oxidative metabolism is different between deep and superficial parts of quadriceps muscles during dynamic exercise.


Assuntos
Metabolismo Energético , Imagem por Ressonância Magnética/métodos , Músculo Esquelético/metabolismo , Adulto , Humanos , Concentração de Íons de Hidrogênio , Masculino , Fosfatos/análise , Fosfocreatina/análise , Fósforo
14.
Magn Reson Med ; 75(6): 2324-31, 2016 06.
Artigo em Inglês | MEDLINE | ID: mdl-26115021

RESUMO

PURPOSE: Simultaneous acquisition of spatially resolved (31) P-MRI data for evaluation of muscle specific energy metabolism, i.e., PCr and pH kinetics. METHODS: A three-dimensional (3D) gradient-echo sequence for multiple frequency-selective excitations of the PCr and Pi signals in an interleaved sampling scheme was developed and tested at 7 Tesla (T). The pH values were derived from the chemical shift-induced phase difference between the resonances. The achieved spatial resolution was ∼2 mL with image acquisition time below 6 s. Ten healthy volunteers were studied performing plantar flexions during the delay between (31) P-MRI acquisitions, yielding a temporal resolution of 9-10 s. RESULTS: Signal from anatomically matched regions of interest had sufficient signal-to-noise ratio to allow single-acquisition PCr and pH quantification. The Pi signal was clearly detected in voxels of actively exercising muscles. The PCr depletions were in gastrocnemius 42 ± 14% (medialis), 48 ± 17% (lateralis) and in soleus 20 ± 11%. The end exercise pH values were 6.74 ± 0.18 and 6.65 ± 0.27 for gastrocnemius medialis and lateralis, respectively, and 6.96 ± 0.12 for soleus muscle. CONCLUSION: Simultaneous acquisition of PCr and Pi images with high temporal resolution, suitable for measuring PCr and pH kinetics in exercise-recovery experiments, was demonstrated at 7T. This study presents a fast alternative to MRS for quantifying energy metabolism of posterior muscle groups of the lower leg. Magn Reson Med 75:2324-2331, 2016. © 2015 Wiley Periodicals, Inc.


Assuntos
Exercício/fisiologia , Processamento de Imagem Assistida por Computador/métodos , Imagem por Ressonância Magnética/métodos , Músculo Esquelético/diagnóstico por imagem , Fosfocreatina/metabolismo , Adulto , Feminino , Humanos , Concentração de Íons de Hidrogênio , Masculino , Músculo Esquelético/metabolismo , Músculo Esquelético/fisiologia , Fosfocreatina/análise , Isótopos de Fósforo/metabolismo , Razão Sinal-Ruído , Adulto Jovem
15.
J Vet Med Sci ; 78(1): 55-9, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26369431

RESUMO

To elucidate the dependence of aerobic energy metabolism and utilization of glucose in contraction of urinary bladder smooth muscle, we investigated the changes in the reduced pyridine nucleotide (PNred) fluorescence, representing glycolysis activity, and determined the phosphocreatine (PCr) and ATP contents of the porcine urinary bladder during contractions induced by high K(+) or carbachol (CCh) and with and without hypoxia (achieved by bubbling N2 instead of O2) or in a glucose-free condition. Hyperosmotic addition of 65 mM KCl (H-65K(+)) and 1 µM CCh induced a phasic contraction followed by a tonic contraction. A glucose-free physiological salt solution (PSS) did not change the subsequent contractile responses to H-65K(+) and CCh. However, hypoxia significantly attenuated H-65K(+)- and CCh-induced contraction. H-65K(+) and CCh induced a sustained increase in PNred fluorescence, representing glycolysis activity. Hypoxia enhanced H-65K(+)- and CCh-induced increases in PNred fluorescence, whereas glucose-free PSS decreased these increases, significantly. In the presence of H-65K(+), hypoxia decreased the PCr and ATP contents; however, the glucose-free PSS did not change the PCr contents. In conclusion, we demonstrated that high K(+)- and CCh-induced contractions depend on aerobic metabolism and that an endogenous substrate may be utilized to maintain muscle contraction in a glucose-free PSS in the porcine urinary bladder.


Assuntos
Hipóxia/veterinária , Contração Muscular/fisiologia , Músculo Liso/fisiopatologia , Bexiga Urinária/fisiopatologia , Trifosfato de Adenosina/análise , Animais , Feminino , Glucose/metabolismo , Hipóxia/complicações , Masculino , Técnicas de Cultura de Órgãos/veterinária , Fosfocreatina/análise , Suínos/fisiologia , Bexiga Urinária/química
16.
PLoS One ; 10(11): e0143972, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26619330

RESUMO

Conventional (CONV) neuromuscular electrical stimulation (NMES) (i.e., short pulse duration, low frequencies) induces a higher energetic response as compared to voluntary contractions (VOL). In contrast, wide-pulse, high-frequency (WPHF) NMES might elicit--at least in some subjects (i.e., responders)--a different motor unit recruitment compared to CONV that resembles the physiological muscle activation pattern of VOL. We therefore hypothesized that for these responder subjects, the metabolic demand of WPHF would be lower than CONV and comparable to VOL. 18 healthy subjects performed isometric plantar flexions at 10% of their maximal voluntary contraction force for CONV (25 Hz, 0.05 ms), WPHF (100 Hz, 1 ms) and VOL protocols. For each protocol, force time integral (FTI) was quantified and subjects were classified as responders and non-responders to WPHF based on k-means clustering analysis. Furthermore, a fatigue index based on FTI loss at the end of each protocol compared with the beginning of the protocol was calculated. Phosphocreatine depletion (ΔPCr) was assessed using 31P magnetic resonance spectroscopy. Responders developed four times higher FTI's during WPHF (99 ± 37 × 10(3) N.s) than non-responders (26 ± 12 × 10(3) N.s). For both responders and non-responders, CONV was metabolically more demanding than VOL when ΔPCr was expressed relative to the FTI. Only for the responder group, the ∆PCr/FTI ratio of WPHF (0.74 ± 0.19 M/N.s) was significantly lower compared to CONV (1.48 ± 0.46 M/N.s) but similar to VOL (0.65 ± 0.21 M/N.s). Moreover, the fatigue index was not different between WPHF (-16%) and CONV (-25%) for the responders. WPHF could therefore be considered as the less demanding NMES modality--at least in this subgroup of subjects--by possibly exhibiting a muscle activation pattern similar to VOL contractions.


Assuntos
Contração Isométrica , Fosfocreatina/análise , Adulto , Estimulação Elétrica/métodos , Feminino , Humanos , Imagem por Ressonância Magnética , Masculino , Fadiga Muscular , Adulto Jovem
17.
NMR Biomed ; 28(10): 1218-27, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26269430

RESUMO

(31)P MRS provides a unique non-invasive window into myocardial energy homeostasis. Mouse models of cardiac disease are widely used in preclinical studies, but the application of (31)P MRS in the in vivo mouse heart has been limited. The small-sized, fast-beating mouse heart imposes challenges regarding localized signal acquisition devoid of contamination with signal originating from surrounding tissues. Here, we report the implementation and validation of three-dimensional image-selected in vivo spectroscopy (3D ISIS) for localized (31)P MRS of the in vivo mouse heart at 9.4 T. Cardiac (31)P MR spectra were acquired in vivo in healthy mice (n = 9) and in transverse aortic constricted (TAC) mice (n = 8) using respiratory-gated, cardiac-triggered 3D ISIS. Localization and potential signal contamination were assessed with (31)P MRS experiments in the anterior myocardial wall, liver, skeletal muscle and blood. For healthy hearts, results were validated against ex vivo biochemical assays. Effects of isoflurane anesthesia were assessed by measuring in vivo hemodynamics and blood gases. The myocardial energy status, assessed via the phosphocreatine (PCr) to adenosine 5'-triphosphate (ATP) ratio, was approximately 25% lower in TAC mice compared with controls (0.76 ± 0.13 versus 1.00 ± 0.15; P < 0.01). Localization with one-dimensional (1D) ISIS resulted in two-fold higher PCr/ATP ratios than measured with 3D ISIS, because of the high PCr levels of chest skeletal muscle that contaminate the 1D ISIS measurements. Ex vivo determinations of the myocardial PCr/ATP ratio (0.94 ± 0.24; n = 8) confirmed the in vivo observations in control mice. Heart rate (497 ± 76 beats/min), mean arterial pressure (90 ± 3.3 mmHg) and blood oxygen saturation (96.2 ± 0.6%) during the experimental conditions of in vivo (31)P MRS were within the normal physiological range. Our results show that respiratory-gated, cardiac-triggered 3D ISIS allows for non-invasive assessments of in vivo mouse myocardial energy homeostasis with (31)P MRS under physiological conditions.


Assuntos
Trifosfato de Adenosina/análise , Imagem Tridimensional/métodos , Espectroscopia de Ressonância Magnética/métodos , Miocárdio/química , Fosfocreatina/análise , Anestesia por Inalação , Anestésicos Inalatórios , Animais , Aorta , Metabolismo Energético , Hemodinâmica , Homeostase , Isoflurano , Ligadura , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Miocárdio/metabolismo , Oxigênio/sangue , Isótopos de Fósforo , Disfunção Ventricular Esquerda/metabolismo , Disfunção Ventricular Esquerda/patologia
19.
Am J Drug Alcohol Abuse ; 41(4): 281-9, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25871447

RESUMO

BACKGROUND: A high prevalence of tobacco smoking has been observed in methamphetamine users, but there have been no in vivo brain neurochemistry studies addressing gender effects of tobacco smoking in methamphetamine users. Methamphetamine addiction is associated with increased risk of depression and anxiety in females. There is increasing evidence that selective analogues of nicotine, a principal active component of tobacco smoking, may ease depression and improve cognitive performance in animals and humans. OBJECTIVES: To investigate the effects of tobacco smoking and gender on brain phosphocreatine (PCr) levels, a marker of brain energy metabolism reported to be reduced in methamphetamine-dependent subjects. METHODS: Thirty female and 27 male methamphetamine-dependent subjects were evaluated with phosphorus-31 magnetic resonance spectroscopy ((31)P-MRS) to measure PCr levels within the pregenual anterior cingulate, which has been implicated in methamphetamine neurotoxicity. RESULTS: Analysis of covariance revealed that there were statistically significant slope (PCr versus lifetime amount of tobacco smoking) differences between female and male methamphetamine-dependent subjects (p = 0.03). In females, there was also a statistically significant interaction between lifetime amounts of tobacco smoking and methamphetamine in regard to PCr levels (p = 0.01), which suggests that tobacco smoking may have a more significant positive impact on brain PCr levels in heavy, as opposed to light to moderate, methamphetamine-dependent females. CONCLUSION: These results indicate that tobacco smoking has gender-specific effects in terms of increased anterior cingulate high energy PCr levels in methamphetamine-dependent subjects. Cigarette smoking in methamphetamine-dependent women, particularly those with heavy methamphetamine use, may have a potentially protective effect upon neuronal metabolism.


Assuntos
Transtornos Relacionados ao Uso de Anfetaminas/complicações , Química Encefálica/efeitos dos fármacos , Metanfetamina/efeitos adversos , Fosfocreatina/análise , Fumar/efeitos adversos , Adulto , Feminino , Humanos , Imagem por Ressonância Magnética , Masculino , Neuroimagem , Fatores Sexuais
20.
NMR Biomed ; 28(4): 505-13, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25802215

RESUMO

Conventional MRI is frequently used during the diagnosis of multiple sclerosis but provides only little additional pathological information. Proton MRS ((1) H-MRS), however, provides biochemical information on the lesion pathology by visualization of a spectrum of metabolites. In this study we aimed to better understand the changes in metabolite concentrations following demyelination of the white matter. Therefore, we used the cuprizone model, a well-established mouse model to mimic type III human multiple sclerosis demyelinating lesions. First, we identified CX3 CL1/CX3 CR1 signaling as a major regulator of microglial activity in the cuprizone mouse model. Compared with control groups (heterozygous CX3 CR1(+/-) C57BL/6 mice and wild type CX3 CR1(+/+) C57BL/6 mice), microgliosis, astrogliosis, oligodendrocyte cell death and demyelination were shown to be highly reduced or absent in CX3 CR1(-/-) C57BL/6 mice. Second, we show that (1) H-MRS metabolite spectra are different when comparing cuprizone-treated CX3 CR1(-/-) mice showing mild demyelination with cuprizone-treated CX3 CR1(+/+) mice showing severe demyelination and demyelination-associated inflammation. Following cuprizone treatment, CX3 CR1(+/+) mice show a decrease in the Glu, tCho and tNAA concentrations as well as an increased Tau concentration. In contrast, following cuprizone treatment CX3 CR1(-/-) mice only showed a decrease in tCho and tNAA concentrations. Therefore, (1) H-MRS might possibly allow us to discriminate demyelination from demyelination-associated inflammation via changes in Tau and Glu concentration. In addition, the observed decrease in tCho concentration in cuprizone-induced demyelinating lesions should be further explored as a possible diagnostic tool for the early identification of human MS type III lesions.


Assuntos
Doenças Desmielinizantes/patologia , Gliose/patologia , Imagem por Ressonância Magnética , Neuroimagem/métodos , Espectroscopia de Prótons por Ressonância Magnética , Animais , Ácido Aspártico/análogos & derivados , Ácido Aspártico/análise , Química Encefálica , Colina/análise , Creatina/análise , Cuprizona/toxicidade , Doenças Desmielinizantes/induzido quimicamente , Doenças Desmielinizantes/diagnóstico , Dipeptídeos/análise , Modelos Animais de Doenças , Feminino , Gliose/induzido quimicamente , Gliose/diagnóstico , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Oligodendroglia/patologia , Fosfocreatina/análise
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA