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Introduction: The aim of this study was to compare age-related changes in chronically infected, asymptomatic HIV-positive patients under combination antiretroviral therapy (cART), with age-, gender-, and educational-level-matched healthy subjects, using multi-voxel magnetic-resonance spectroscopy (MRS). Methods: There were 66 chronically infected HIV-positive subjects and 65 age-, gender-, and educational-level-matched control subjects, divided into four groups according to the age: group 1 (20-29 years old), group 2 (30-39), group 3 (40-49) and group 4 (50-59). MRS was performed and ratios of N-acetyl-aspartate (NAA)/creatine (Cr) were analyzed in ten locations of the supracallosal gray matter. For the comparison of NAA/Cr ratios in healthy and HIV-positive subjects, ANCOVA with age and education as covariates was performed. Correlations of NAA/Cr ratios with duration of cART were performed using Pearson's correlation test. Statistical significance was set at p < 0.05. Results: The NAA/Cr ratios were decreased in the 20-29-year-old HIV-positive subjects in 8/10 locations (p < 0.005) compared to the healthy controls, while in the 50-59-year-old groups they were significiantly lower only in one location (p = 0.004). There were significant positive correlations of NAA/Cr levels with the duration of cART in the oldest group of HIV-positive subjects, while in the youngest group there were no significant correlations. Conclusion: The aging pattern in chronic HIV infection under cART is accentuated rather than accelerated. There is an initial HIV-related neuronal damage with a significant decline in NAA/Cr ratios; after the initiation of cART, however, NAA/Cr ratios increase continuously to become similar to healthy aging individuals, probably due to beneficial effect of long-standing cART. Summary: Brain aging in chronic HIV infection under cART is accentuated, with an initial HIV-related neuronal damage followed by a subtle NAA/Cr increase after the initiation of cART. Under cART, in advanced age, NAA/Cr ratios become similar to healthy aging individuals.
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The aim of this study was to evaluate the resolution of brain lesions in patients with Wilson's disease during the long-term chelating therapy using magnetic resonance imaging and a possible significance of the time latency between the initial symptoms of the disease and the introduction of this therapy. Initial magnetic resonance examination was performed in 37 patients with proven neurological form of Wilson's disease with cerebellar, parkinsonian and dystonic presentation. Magnetic resonance reexamination was done 5.7 ± 1.3 years later in 14 patients. Patients were divided into: group A, where chelating therapy was initiated < 24 months from the first symptoms and group B, where the therapy started ≥ 24 months after the initial symptoms. Symmetry of the lesions was seen in 100% of patients. There was a significant difference between groups A and B regarding complete resolution of brain stem and putaminal lesions (P = 0.005 and P = 0.024, respectively). If the correct diagnosis and adequate treatment are not established less than 24 months after onset of the symptoms, irreversible lesions in the brain parenchyma could be expected. Signal abnormalities on magnetic resonance imaging might therefore, at least in the early stages, represent reversible myelinolisis or cytotoxic edema associated with copper toxicity.
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We present a case of partial rhombencephalosynapsis, diagnosed by magnetic resonance imaging (MRI), in fetus aged 27 gestational weeks, in a dizygotic twin pregnancy. The distinctive MRI features of this cerebellar malformation (segmental hypogenesis of the cerebellar vermis, partial fusion of the cerebellar hemispheres and dentate nuclei) without associated cerebral abnormalities were confirmed by 32-weeks prenatal and 3-months postnatal MRI studies. At the age of 12 months the affected twin had a slight delay in psychomotor development, mild hypotonia with normal cognitive development. To the authors' best knowledge, this is the first report of a fetal case with isolated partial rhombencephalosynapsis. Its MRI features enlarges the narrow spectrum of uncommon variants of rhombencephalosynapsis, and allow an accurate differentiation from other vermian and cerebellar anomalies with less favorable postnatal outcome.
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Imageamento por Ressonância Magnética/métodos , Diagnóstico Pré-Natal/métodos , Rombencéfalo/anormalidades , Rombencéfalo/patologia , Adulto , Doenças em Gêmeos , Feminino , Número de Gestações , Humanos , Estudos Longitudinais , GravidezRESUMO
PURPOSE: To determine the triceps brachii functional adaptation and regional body composition changes after 12 months of detraining. MATERIALS AND METHODS: Seventeen healthy young men (22.2 ± 1.0 y, body mass index 24.9 ± 3.1 kg/m(2) ) were put in the detraining regimen for 12 months after completing a 12-week exercise protocol on isoacceleration dynamometer (5 times a week, 5 daily series with 10 maximal elbow extensions, 1 min rest between sets). Triceps brachii muscle strength was measured by isoacceleration dynamometry, using identical protocol as during the training. Muscle volumes, subcutaneous adipose tissue (SCAT), and intermuscular adipose tissue (IMAT) at mid-humerus were assessed by using MRI. RESULTS: Long-term detraining resulted in the significant decrease of 17% and 19% in endurance strength and fatigue rate, respectively. Maximal muscle strength slightly changed, and its 4% decrease was not significant. Triceps brachii volumes of both arms returned to their pretraining values (475.7 ± 54.91 cm(3) for right arm, and 483.9 ± 77.5 cm(3) for left arm). IMAT depots in upper arm significantly increased by 14% after 12 months of detraining, when compared with baseline values (P < 0.05). CONCLUSION: Long-term detraining leads to triceps brachii adaptation with endurance strength decrease, volume return to its baseline values, and significant IMAT accumulation. IMAT values after 12 months of detraining exceed baseline, pretraining values, which is significant accumulation as a result of physiologically decreased muscle activity.
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Imageamento por Ressonância Magnética/métodos , Força Muscular/fisiologia , Músculo Esquelético/patologia , Aceleração , Tecido Adiposo/patologia , Adulto , Composição Corporal , Índice de Massa Corporal , Exercício Físico/fisiologia , Humanos , Masculino , Modelos Biológicos , Músculos/patologiaRESUMO
The aim of this study was to determine morphological and functional changes of the elbow extensor muscles in response to a 12-week self-perceived maximal resistance training (MRT). Twenty-one healthy sedentary young men were engaged in elbow extensor training using isoacceleration dynamometry for 12 weeks with a frequency of five sessions per week (five sets of ten maximal voluntarily contractions, 1-min rest period between each set). Prior to, at 6 weeks and after the training, a series of cross-sectional magnetic resonance images of the upper arm were obtained and muscle volumes were calculated. Maximal and endurance strength increased (P<0.01) by 15% and 45% at 6 weeks, and by 29% and 70% after 12 weeks compared with baseline values, while fatigue rate of the elbow extensors decreased by 67%. The volume of triceps brachii increased in both arms (P<0.01) by 4% at 6 weeks, and by 8% after 12 weeks compared with baseline values (right arm--from 487.4 ± 72.8 cm³ to 505.8 ± 72.3 cm³ after 6 weeks and 525.3 ± 73.7 cm³ after 12 weeks; left arm--from 475.3 ± 79.1 cm³ to 493.2 ± 72.7 cm³ after 6 weeks and 511.3 ± 77.0 cm³ after 12 weeks). A high correlation was found between maximal muscle strength and muscle volume prior (r² = 0.62) and after (r² = 0.69) the training (P≤0.05). A self-perceived MRT resulted in an increase in maximal and endurance strength. Morphological adaptation changes of triceps brachii as a result of 12-week specific strength training can explain only up to 26% of strength gain.
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Contração Muscular , Músculo Esquelético/fisiopatologia , Percepção , Treinamento Resistido , Adaptação Fisiológica , Cotovelo , Humanos , Hipertrofia , Imageamento por Ressonância Magnética , Masculino , Fadiga Muscular , Força Muscular , Dinamômetro de Força Muscular , Músculo Esquelético/patologia , Tamanho do Órgão , Resistência Física , Fatores de Tempo , Adulto JovemRESUMO
PURPOSE: To evaluate the effect of 6-week self-perceived maximal resistance training on muscle volume utilizing magnetic resonance imaging and maximal, average, and endurance strength of the elbow extensors and to assess the relationship between muscle strength and volume before and after the training. MATERIALS AND METHODS: This was a prospective blinded study. A total of 15 healthy untrained men, aged 22.5+/-3.7 years (mean+/-SD), were engaged in elbow extensor training using isoacceleration dynamometry for 6 weeks with a frequency of five sessions per week (five sets of 10 maximal voluntary contractions, 1-minute rest period between each set). Prior to and after the training, cross-sectional magnetic resonance images of the upper arm were obtained and muscle volumes were calculated using the truncated cone formula. RESULTS: Average, maximal, and endurance strength of the upper arm extensors increased significantly by 43%, 15%, and 56%, respectively. The volume of triceps brachii increased in both arms (P<0.05): right from 456.9+/-113.8 cm3 to 475.8+/-100.9 cm3 and left from 444.3+/-121.9 cm3 to 468.4+/-110.4 cm3, or 5%. Maximal and average strength correlated significantly with muscle volume before and after the training. CONCLUSION: A specific 6-week resistance training protocol resulted in muscle strength improvement, together with increase in triceps brachii muscle volume, as demonstrated by volumetric imaging.
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Imageamento por Ressonância Magnética/métodos , Músculo Esquelético/anatomia & histologia , Músculo Esquelético/fisiologia , Resistência Física/fisiologia , Esforço Físico/fisiologia , Treinamento Resistido/métodos , Adulto , Braço , Humanos , Imageamento Tridimensional/métodos , Contração Isométrica/fisiologia , Masculino , Dinamômetro de Força Muscular , Estudos Prospectivos , Valores de Referência , Adulto JovemRESUMO
Leptomeningeal metastasis from malignant mesothelioma is very rare; to our knowledge, only one imaging report exists in the literature. We present the case of widespread leptomeningeal lesions secondary to a malignant mesothelioma in a 61-year-old woman.