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1.
Forensic Sci Int ; 359: 112033, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38678987

RESUMO

Recent events in conflict zones have emphasized that the successful detection and characterisation of buried clandestine complexes, bunkers and tunnels is vitally important for forensic investigators globally, to reduce or solve criminal activities, address national security threats and avoid potential terrorist attacks. However, this can often prove very difficult, particularly in urban areas, with potentially both below-ground non target items and above-ground infrastructures present, that can interfere with detecting target(s). Here we provide selected successful case studies where forensic geoscience techniques were used to detect and characterise buried clandestine complexes, bunkers and tunnels using different geophysical techniques. Generally, desktop studies assessing pre-existing information, including local geology, soils, historical/modern remote sensing, maps and photographs inform appropriate geophysical survey technique(s) selection. Subsequent near-surface geophysical techniques are then employed to produce accurate plans of sub-surface targets, with numerical modelling and correction for the interfering effects of above ground infrastructure, enabling the calibration of geophysical datasets to provide confidence in their respective interpretations. All forensic investigations are, of course, unique to every site, and thus require an individual approach to their respective ground conditions. Investigations should be both phased and iterative, with techniques tailored to local conditions: the selection of geophysical method(s) is crucial to improve successful detection rates of such important buried targets.

3.
Stroke ; 40(12): 3740-4, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19834021

RESUMO

BACKGROUND AND PURPOSE: Previous (31)P-magnetic resonance spectroscopy ((31)P-MRS) studies have shown that cerebral cortical energy metabolism is abnormal in migraine and that cortical energy reserves decrease with increasing severity and duration of aura. Migrainous infarction is a rare complication of migraine with aura, and its pathophysiology is poorly understood. We used (31)P-MRS to determine whether migrainous stroke shows similar interictal abnormalities in cortical energy metabolism as severe, prolonged aura. METHODS: We used (31)P-MRS to study patients with a diagnosis of either migrainous infarction or migraine with persistent aura without infarction (aura duration >7 days) according to International Headache Society criteria. We compared clinical presentation and metabolite ratios between patient groups. We also studied healthy controls with no history of migraine. RESULTS: Patients with persistent aura without infarction had lower phosphocreatine-phosphate (PCr/Pi) ratios (mean+/-SD, 1.61+/-0.10) compared with controls (1.94+/-0.35, P=0.011) and with patients with migrainous stroke (1.96+/-0.16, P<0.0001). These differences were present in cortical tissue only. In migrainous stroke patients, the metabolite ratios did not differ significantly from those of controls without migraine. CONCLUSIONS: The differences in cortical energy reserves between patients with migrainous stroke and in those with migraine with persistent aura suggest that the pathomechanisms of these conditions differ and that migrainous infarction does not simply represent a particularly severe form of migrainous aura. This finding supports the revised International Headache Society criteria, which now distinguish between migrainous infarction and migraine with persistent aura without infarction.


Assuntos
Córtex Cerebral/metabolismo , Metabolismo Energético/fisiologia , Transtornos de Enxaqueca/diagnóstico , Transtornos de Enxaqueca/metabolismo , Acidente Vascular Cerebral/diagnóstico , Acidente Vascular Cerebral/metabolismo , Biomarcadores/análise , Biomarcadores/metabolismo , Córtex Cerebral/fisiopatologia , Diagnóstico Diferencial , Espectroscopia de Ressonância Magnética/métodos , Transtornos de Enxaqueca/complicações , Enxaqueca com Aura/diagnóstico , Enxaqueca com Aura/metabolismo , Fosfatos/análise , Fosfatos/metabolismo , Fosfocreatina/análise , Fosfocreatina/metabolismo , Radioisótopos de Fósforo , Valor Preditivo dos Testes , Acidente Vascular Cerebral/etiologia
4.
Synapse ; 61(11): 925-32, 2007 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-17701967

RESUMO

BACKGROUND: Acute depletion of tyrosine using a tyrosine-free amino acid mixture offers a novel dietary approach to inhibit activated dopamine pathways in the brain. This study investigated the potential of in vivo functional magnetic resonance imaging (fMRI) methods as a noninvasive means to detect effects of tyrosine depletion on dopamine function. METHODS: Changes in blood-oxgenation level dependent (BOLD) contrast induced by administration of the dopamine-releasing agent, amphetamine (3 mg/kg i.v.), were measured in halothane-anaesthetised rats. RESULTS: Amphetamine evoked changes in BOLD signal intensity with the greatest effects observed in the nucleus accumbens (-7.7%), prefrontal cortex (-13.6%), and motor cortex (+12.5%). Pretreatment with a tyrosine-free amino acid mixture attenuated the response to amphetamine in some regions (nucleus accumbens and prefrontal cortex), but not others (motor cortex). Amphetamine itself had no effect in thalamus and hippocampus but, surprisingly, increased the BOLD signal after the amino acid mixture. CONCLUSION: These experiments demonstrate that amphetamine evokes region-specific changes in the BOLD signal in rats, and that this effect is attenuated in some but not all regions by tyrosine depletion. The data support the application of fMRI techniques for studying the effects of tyrosine depletion on dopamine function in animals and also humans.


Assuntos
Anfetamina/farmacologia , Encéfalo/irrigação sanguínea , Encéfalo/efeitos dos fármacos , Inibidores da Captação de Dopamina/farmacologia , Imageamento por Ressonância Magnética , Tirosina/deficiência , Animais , Encéfalo/anatomia & histologia , Mapeamento Encefálico , Processamento de Imagem Assistida por Computador , Masculino , Oxigênio/sangue , Ratos , Ratos Sprague-Dawley , Fatores de Tempo
5.
J Cardiovasc Magn Reson ; 9(4): 709-17, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17578728

RESUMO

BACKGROUND: The Marfan syndrome is an inherited multisystem disorder caused by mutations in fibrillin 1, with cardiovascular involvement being the most important feature of the phenoptype. Affected individuals have impaired flow-mediated dilatation (FMD) of large arteries of a similar severity to patients with chronic heart failure (CHF). AIMS: Skeletal muscle bioenergetics were studied in patients with the Marfan syndrome in order to evaluate the impact of impaired flow-mediated dilatation on skeletal muscle metabolism. Skeletal muscle metabolism is abnormal in CHF and the aetiology is unclear. METHODS: Thirteen patients and 12 controls were studied by phosphorus Magnetic Resonance spectroscopy of the calf muscle using an incremental exercise protocol and by Magnetic Resonance imaging. RESULTS: Metabolic variables measured at rest were normal in Marfan patients. For a similar total work output measured at end of the standardized incremental exercise, the total rate of energy consumption (EC) was significantly increased in patients (21.2 +/- 2.3 mM ATP/min/W vs 13.6 +/- 1.4 mM ATP/min/W in controls). Similarly, both PCr and pH time-dependent changes were significantly different between groups. The absolute contributions of aerobic and glycolytic pathways to energy production were significantly higher in patients whereas they were similar when expressed relative to EC. CONCLUSIONS: The higher EC measured in patients with Marfan syndrome was supported by both oxidative and anaerobic metabolic pathways, thereby suggesting a decrease in muscle efficiency and/or muscle mass, as previously described in other diseases affecting skeletal muscle function such as heart failure and peripheral vascular disease.


Assuntos
Metabolismo Energético , Espectroscopia de Ressonância Magnética/métodos , Síndrome de Marfan/metabolismo , Músculo Esquelético/metabolismo , Adolescente , Adulto , Análise de Variância , Estudos de Casos e Controles , Feminino , Humanos , Perna (Membro) , Masculino , Síndrome de Marfan/fisiopatologia , Pessoa de Meia-Idade , Músculo Esquelético/fisiopatologia , Fosfocreatina/metabolismo , Fósforo/metabolismo , Descanso
6.
Neurobiol Dis ; 26(3): 707-17, 2007 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-17490889

RESUMO

Prion diseases are fatal chronic neurodegenerative diseases. Previous qualitative magnetic resonance imaging (MRI) and spectroscopy (MRS) studies report conflicting results in the symptomatic stages of the disease, but little work has been carried out during the earlier stages of the disease. Here we have used the murine ME7 model of prion disease to quantitatively investigate MRI and MRS changes during the period prior to the onset of overt clinical signs (20+ weeks) and have correlated these with pathological and behavioural abnormalities. Using in vivo MRI, at the later stages of the preclinical period (18 weeks) the diffusion of tissue water was significantly reduced, coinciding with significant microglial activation and behavioural hyperactivity. Using in vivo MRS, we found early (12 weeks) decreases in the ratio of N-acetyl aspartate to both choline (NAA/Cho) and creatine (NAA/Cr) in the thalamus and hippocampus, which were associated with early behavioural deficits. Ex vivo MRS of brain extracts confirmed and extended these findings, showing early (8-12 weeks) decreases in both the neuronal metabolites NAA and glutamate, and the metabolic metabolites lactate and glucose. Increases in the glial metabolite myo-inositol were observed at later stages when microglial and astrocyte activation is substantial. These changes in MRI and MRS signals, which precede overt clinical signs of disease, could provide insights into the pathogenesis of this disease and may enable early detection of pathology.


Assuntos
Encéfalo/patologia , Imageamento por Ressonância Magnética/métodos , Espectroscopia de Ressonância Magnética/métodos , Doenças Priônicas/diagnóstico , Doenças Priônicas/patologia , Animais , Ácido Aspártico/análogos & derivados , Ácido Aspártico/análise , Ácido Aspártico/metabolismo , Astrócitos/metabolismo , Água Corporal/fisiologia , Encéfalo/metabolismo , Encéfalo/fisiopatologia , Colina/análise , Colina/metabolismo , Creatina/análise , Creatina/metabolismo , Difusão , Modelos Animais de Doenças , Progressão da Doença , Gliose/etiologia , Gliose/patologia , Gliose/fisiopatologia , Glucose/metabolismo , Ácido Glutâmico/análise , Ácido Glutâmico/metabolismo , Hipercinese/etiologia , Hipercinese/patologia , Hipercinese/fisiopatologia , Inositol/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Microglia/metabolismo , Doenças Priônicas/fisiopatologia
7.
Eur J Heart Fail ; 9(3): 287-91, 2007 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-17023203

RESUMO

BACKGROUND: Chronic heart failure (CHF) is associated with abnormalities of skeletal muscle metabolism. This may be due to impaired oxygen delivery as a result of endothelial dysfunction. AIMS: We postulated that ascorbic acid would improve oxygen delivery to exercising muscle and improve skeletal muscle metabolism. METHODS: We studied skeletal muscle metabolism using (31)P magnetic resonance spectroscopy in 39 CHF patients. Endothelial function was assessed by changes in pulse wave velocity. Subjects were randomised to receive 4 g ascorbic acid daily for 4 weeks in a placebo-controlled double-blind study. RESULTS: Ascorbic acid significantly increased phosphocreatine utilization during exercise. In addition, glycolytic ATP synthesis increased in the ascorbic acid group (change in rate of ATP synthesis at 1 min -0.21+/-0.76 with placebo, 2.06+/-0.60 following ascorbic acid; p<0.05). Phosphocreatine and ADP recovery after exercise were not changed. The fall in pulse wave velocity during reactive hyperaemia was increased by ascorbic acid from -6.3+/-2.6% to -12.1+/-2.0% (p<0.05). CONCLUSIONS: These findings suggest that ascorbic acid increased both phosphocreatine utilization and glycolytic ATP synthesis during exercise in patients with CHF implying worsened skeletal muscle metabolism despite improvements in endothelial function.


Assuntos
Ácido Ascórbico/uso terapêutico , Endotélio Vascular/efeitos dos fármacos , Insuficiência Cardíaca/metabolismo , Músculo Esquelético/efeitos dos fármacos , Trifosfato de Adenosina/biossíntese , Idoso , Ácido Ascórbico/sangue , Doença Crônica , Método Duplo-Cego , Endotélio Vascular/fisiopatologia , Feminino , Insuficiência Cardíaca/fisiopatologia , Humanos , Espectroscopia de Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Músculo Esquelético/metabolismo , Fosfocreatina/metabolismo , Reino Unido
8.
Arch Neurol ; 62(4): 621-6, 2005 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15824263

RESUMO

BACKGROUND: Decreased mitochondrial respiratory chain function and increased oxidative stress have been implicated in the pathogenesis of Friedreich ataxia (FRDA), raising the possibility that energy enhancement and antioxidant therapies may be an effective treatment. OBJECTIVE: To evaluate the long-term efficacy of a combined antioxidant and mitochondrial enhancement therapy on the bioenergetics and clinical course of FRDA. DESIGN: Open-labeled pilot trial over 47 months.Patients Seventy-seven patients with clinical and genetically defined FRDA. Intervention A combined coenzyme Q(10) (400 mg/d) and vitamin E (2100 IU/d) therapy of 10 patients with FRDA over 47 months. MAIN OUTCOME MEASURES: Clinical assessment using echocardiography and the International Cooperative Ataxia Rating Scale and cardiac and skeletal muscle bioenergetics as assessed using phosphorus P 31 magnetic resonance spectroscopy. RESULTS: There was a significant improvement in cardiac and skeletal muscle bioenergetics that was maintained throughout the 47 months of therapy. Echocardiographic data revealed significantly increased fractional shortening at the 35- and 47-month time points. Comparison with cross-sectional data from 77 patients with FRDA indicated the changes in total International Cooperative Ataxia Rating Scale and kinetic scores over the trial period were better than predicted for 7 patients, but the posture and gait and hand dexterity scores progressed as predicted. CONCLUSION: This therapy resulted in sustained improvement in mitochondrial energy synthesis that was associated with a slowing of the progression of certain clinical features and a significant improvement in cardiac function.


Assuntos
Antioxidantes/administração & dosagem , Metabolismo Energético/efeitos dos fármacos , Ataxia de Friedreich/tratamento farmacológico , Mitocôndrias/efeitos dos fármacos , Músculo Esquelético/efeitos dos fármacos , Ubiquinona/análogos & derivados , Ubiquinona/administração & dosagem , Vitamina E/administração & dosagem , Adolescente , Adulto , Criança , Coenzimas , Quimioterapia Combinada , Metabolismo Energético/fisiologia , Seguimentos , Ataxia de Friedreich/metabolismo , Ataxia de Friedreich/fisiopatologia , Coração/efeitos dos fármacos , Coração/fisiopatologia , Humanos , Proteínas de Ligação ao Ferro/genética , Pessoa de Meia-Idade , Mitocôndrias/metabolismo , Músculo Esquelético/metabolismo , Músculo Esquelético/fisiopatologia , Miocárdio/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/fisiologia , Projetos Piloto , Resultado do Tratamento , Frataxina
9.
J Cereb Blood Flow Metab ; 25(2): 204-16, 2005 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-15678123

RESUMO

Magnetic resonance imaging (MRI) is an established clinical tool for diagnosing multiple sclerosis (MS), the archetypal central nervous system neuroinflammatory disease. In this study, we have used a model of delayed-type hypersensitivity in the rat brain, which bears many of the hallmarks of an MS lesion, to investigate the development of MRI-detectable changes before the appearance of conventional indices of lesion development. In addition, we have correlated the MRI-detectable changes with the developing histopathology. Significant increases in regional cerebral blood volume (rCBV) preceded overt changes in blood-brain barrier (BBB) permeability, T2 relaxation and the diffusion properties of tissue water. Thus, changes in rCBV might be a more sensitive indicator of lesion onset than the conventional indices used clinically in MS patients, such as contrast enhancement. In addition, we show that BBB breakdown, and consequent edema formation, are more closely correlated with astrogliosis than any other histopathologic changes, while regions of T1 and T2 hypointensity appear to reflect hypercellularity.


Assuntos
Volume Sanguíneo/fisiologia , Barreira Hematoencefálica/patologia , Encéfalo/irrigação sanguínea , Encéfalo/diagnóstico por imagem , Animais , Encéfalo/patologia , Modelos Animais de Doenças , Hipersensibilidade Tardia/patologia , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Masculino , Esclerose Múltipla/fisiopatologia , Permeabilidade , Intensificação de Imagem Radiográfica , Ratos , Ratos Endogâmicos Lew
10.
J Neurotrauma ; 21(6): 645-54, 2004 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-15253793

RESUMO

Following diffuse traumatic brain injury, there may be persistent functional or psychological deficits despite the presence of normal conventional MR images. Previous experimental animal and human studies have shown diffusion abnormalities following focal brain injury. Our aim was to quantify changes in apparent diffusion coefficient (ADC) and absolute relaxation times of normal appearing white matter (NAWM) in humans following traumatic brain injury. Twenty-three patients admitted with a diagnosis of head injury (nine mild, eight moderate, and six severe) were scanned an average of 7.6 days after injury using a quantitative echo planar imaging acquisition to obtain co-registered T1, T2, and ADC parametric maps. Mean NAWM values were compared with a control group (n = 13). The patient group showed a small but significant increase in ADC in NAWM, with no significant change in T1 or T2 relaxation times. There was a correlation between injury severity and increasing ADC (p = 0.03) but no correlation with either T1 or T2, suggesting that ADC is a sensitive and independent marker of diffuse white matter tissue damage following traumatic insult. None of the patients had a reduced ADC, making ischaemia unlikely in this cohort. Pathophysiological mechanisms that may explain diffusely raised ADC include vasogenic edema, chronic ischemic phenomena, or changes in tissue cytoarchitecture or neurofilament alignment.


Assuntos
Lesões Encefálicas/patologia , Lesões Encefálicas/fisiopatologia , Encéfalo/patologia , Encéfalo/fisiopatologia , Adolescente , Adulto , Estudos de Casos e Controles , Estudos de Coortes , Difusão , Imagem de Difusão por Ressonância Magnética , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Tempo , Índices de Gravidade do Trauma
11.
Biochim Biophys Acta ; 1657(2-3): 146-50, 2004 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-15238271

RESUMO

Cardiomyopathy is a frequent cause of morbidity and mortality in patients carrying the A3243G transition in the mitochondrial DNA (mtDNA) tRNALeu(UUR) gene, the most common heteroplasmic single mtDNA defect. We used phosphorus magnetic resonance spectroscopy (31P-MRS) to look for evidence of an in vivo bioenergetics defect in patients carrying the A3243G mtDNA mutation with and without echocardiographic signs of left ventricle hypertrophy (LVH). Eight patients, three with LVH, carrying the A3243G mtDNA mutation and 10 healthy subjects underwent one-dimensional chemical shift imaging 31P-MRS. In the patients, mean cardiac phosphocreatine to adenosine triphosphate ratio (PCr/ATP) (1.55 +/- 0.58) was significantly reduced compared to the control group (2.34 +/- 0.14; P < 0.001). Cardiac PCr/ATP was within the normal range only in one case that showed normal echocardiography. Our results point to a central role of bioenergetics deficit in the development of cardiac hypertrophy in patients with the A3243G mtDNA mutation. Impaired cardiac energy metabolism in patients with normal echocardiography suggests that the enhancement of mitochondrial function may be beneficial not only to patients with cardiac hypertrophy but also to those patients carrying the mutation in the absence of signs of cardiac hypertrophy and/or dysfunction but with cardiac bioenergetics deficit.


Assuntos
DNA Mitocondrial/genética , Imageamento por Ressonância Magnética/métodos , Mutação , Miocárdio/metabolismo , Adulto , Ecocardiografia , Feminino , Humanos , Masculino , Fósforo
12.
FEBS Lett ; 568(1-3): 49-54, 2004 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-15196919

RESUMO

Multiple sclerosis is a major cause of non-traumatic neurological disability. The identification of markers that differentiate disease progression is critical to effective therapy. A combination of NMR spectroscopic metabolic profiling of urine and statistical pattern recognition was used to detect focal inflammatory central nervous system (CNS) lesions induced by microinjection of a replication-deficient recombinant adenovirus expressing TNF-alpha or IL1-beta cDNA into the brains of Wistar rats. These animals were compared with a group of naïve rats and a group of animals injected with an equivalent null adenovirus. Urine samples were collected 7 days after adenovirus injection, when the inflammatory lesion is maximally active. Principal components analysis and Partial Least Squares-Discriminate analysis of the urine (1)H NMR spectra revealed significant differences between each of the cytokine adenovirus groups and the control groups; for the TNF-alpha group the main differences lay in citrate and succinate, while for the IL-1beta group the predominant changes occurred in leucine, isoleucine, valine and myo-inositol. Thus, we can identify urinary metabolic vectors that not only separate rats with inflammatory lesions in the brain from control animals, but also distinguish between different types of CNS inflammatory lesions.


Assuntos
Encéfalo/patologia , Interleucina-1/urina , Fator de Necrose Tumoral alfa/urina , Adenoviridae/genética , Animais , DNA Complementar , Vírus Defeituosos/genética , Interleucina-1/genética , Interleucina-1/fisiologia , Ressonância Magnética Nuclear Biomolecular , Ratos , Ratos Wistar , Fator de Necrose Tumoral alfa/genética , Fator de Necrose Tumoral alfa/fisiologia
13.
Magn Reson Med ; 51(2): 248-52, 2004 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-14755648

RESUMO

MRI is an increasingly important clinical tool, but it is clear that conventional imaging fails to identify the full extent of lesion load in certain conditions, such as multiple sclerosis. The aim of this study was to determine whether a novel contrast agent (Gd-DTPA-B(sLeX)A, which contains an sLeX mimetic moiety that enables it to bind to the adhesion molecule E-selectin) can be used to identify endothelial activation in the brain. Microinjection of the proinflammatory cytokines IL-1beta or TNF-alpha into the striatum of Wistar rats rapidly induces focal adhesion molecule expression on the endothelium in the absence of MRI-visible changes. This phenomenon was used to investigate the potential of Gd-DTPA-B(sLeX)A to reveal MRI-invisible brain pathology. T1-weighted serial images were acquired in anesthetized animals before and after administration of Gd-DTPA-B(sLeX)A, 3-4 hr after cytokine was injected intracerebrally. Both TNF-alpha and IL-1beta up-regulated E-selectin on the brain endothelium, which correlated with increased signal intensity observed after administration of the novel contrast agent. No enhancement was visible with the nonselective contrast agent Gd-DTPA-BMA, indicating that there was no leakage of the agent across the blood-brain barrier (BBB) or nonselective binding to the endothelium. These data demonstrate the potential of such contrast agents for the early detection of brain injury and inflammation.


Assuntos
Selectina E/metabolismo , Encefalite/metabolismo , Imageamento por Ressonância Magnética/métodos , Animais , Meios de Contraste , Gadolínio DTPA , Injeções , Interleucina-1/administração & dosagem , Interleucina-1/farmacologia , Masculino , Ratos , Ratos Wistar , Fator de Necrose Tumoral alfa/administração & dosagem , Fator de Necrose Tumoral alfa/farmacologia
14.
Dev Neurosci ; 25(5): 324-31, 2003.
Artigo em Inglês | MEDLINE | ID: mdl-14614259

RESUMO

We obtained (31)P magnetic resonance spectra from the brains in vivo of 101 males (range 6-72 years). In addition, cognitive test data were obtained from 42 boys (6-13 years) and from 26 adult males (22-56 years) of this test group. Significant correlations were observed in both adults and children between various inorganic phosphate (Pi)-containing (31)P peak ratios [e.g. Pi/adenosine triphosphate (ATP)] and (predominantly verbal) cognitive tasks. No change in the Pi/ATP ratio was observed across the age range studied. Brain pH was shown to decrease significantly with age in a relationship best described by a decaying exponential. This indicated that brain pH does not stabilize at adult values until at least the late teens. We explored the possibility of a relationship between brain pH and neuronal density. In particular, we noted that our previous observation of a relationship between pH and IQ in children was not readily detected in the adult populations, whereas phosphorus metabolite ratios (in particular, those containing Pi) were found to correlate with (predominantly verbal) cognitive task performance in both adults and children. We assessed how these observations may be interpreted in the context of a metabolic vs. histological debate.


Assuntos
Envelhecimento , Química Encefálica/fisiologia , Encéfalo/fisiologia , Cognição/fisiologia , Metabolismo Energético , Adolescente , Adulto , Idoso , Criança , Humanos , Concentração de Íons de Hidrogênio , Testes de Inteligência , Espectroscopia de Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Isótopos de Fósforo/análise , Isótopos de Fósforo/metabolismo
15.
Clin Neurol Neurosurg ; 105(3): 193-202, 2003 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-12860514

RESUMO

Magnetic resonance techniques were used to investigate haemodynamic abnormalities and their consequences in normal pressure hydrocephalus (NPH) and to assess changes in these parameters following surgery. Eleven patients with NPH were studied pre- and post-operatively using perfusion and diffusion weighted imaging and compared with ten age-matched controls. Pre-operative periventricular relative cerebral blood volume (rCBV) was reduced in patients (0.76+/-0.11) compared with control (1.16+/-0.16, P<0.01). There was no difference between outcome groups and no change in haemodynamic parameters following surgery. The periventricular apparent diffusion coefficient (ADC) was elevated in the poor outcome group (1.67+/-0.3 x 10(-3) mm(2) s(-1)) compared with both controls (1.04+/-0.4 x 10(-3) mm(2) s(-1), P<0.05) and the good outcome group (0.99+/-0.3 x 10(-3) mm(2) s(-1), P<0.05) despite appearing normal on conventional imaging. In white matter hyperintensities (WMH), rCBV was reduced (0.70+/-0.12 vs. 1.00+/-0.10, P<0.01), and the ADC was increased (1.98+/-0.6 vs. 1.04+/-0.4 x 10(-3) mm(2) s(-1), P<0.05) compared with the same anatomical location in controls. As low rCBV and high ADC is characteristic of chronic infarction, the findings in WMH regions suggest they are irreversibly damaged. Normal appearing periventricular tissue rCBV was reduced, implying that significant haemodynamic consequences contribute to symptoms in NPH. The elevated pre-operative ADC of the same region, was correlated with poor outcome, and may, therefore, be useful in selecting patients for surgery.


Assuntos
Encéfalo/fisiopatologia , Hidrocefalia de Pressão Normal/fisiopatologia , Idoso , Idoso de 80 Anos ou mais , Encéfalo/patologia , Circulação Cerebrovascular , Humanos , Hidrocefalia de Pressão Normal/cirurgia , Imageamento por Ressonância Magnética , Pessoa de Meia-Idade , Resultado do Tratamento , Derivação Ventriculoperitoneal
16.
Circulation ; 107(24): 3040-6, 2003 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-12810608

RESUMO

BACKGROUND: It is well known that patients with type 2 diabetes have increased risk of cardiovascular disease, but it is not known whether they have underlying abnormalities in cardiac or skeletal muscle high-energy phosphate metabolism. METHODS AND RESULTS: We studied 21 patients with type 2 diabetes with no evidence of coronary artery disease or impaired cardiac function, as determined by echocardiography, and 15 age-, sex-, and body mass index-matched control subjects. Cardiac high-energy phosphate metabolites were measured at rest using 31P nuclear magnetic resonance spectroscopy (MRS). Skeletal muscle high-energy phosphate metabolites, intracellular pH, and oxygenation were measured using 31P MRS and near infrared spectrophotometry, respectively, before, during, and after exercise. Although their cardiac morphology, mass, and function appeared to be normal, the patients with diabetes had significantly lower phosphocreatine (PCr)/ATP ratios, at 1.50+/-0.11, than the healthy volunteers, at 2.30+/-0.12. The cardiac PCr/ATP ratios correlated negatively with the fasting plasma free fatty acid concentrations. Although skeletal muscle energetics and pH were normal at rest, PCr loss and pH decrease were significantly faster during exercise in the patients with diabetes, who had lower exercise tolerance. After exercise, PCr recovery was slower in the patients with diabetes and correlated with tissue reoxygenation times. The exercise times correlated negatively with the deoxygenation rates and the hemoglobin (Hb)A1c levels and the reoxygenation times correlated positively with the HbA1c levels. CONCLUSIONS: Type 2 diabetic patients with apparently normal cardiac function have impaired myocardial and skeletal muscle energy metabolism related to changes in circulating metabolic substrates.


Assuntos
Diabetes Mellitus Tipo 2/metabolismo , Metabolismo Energético , Músculo Esquelético/metabolismo , Miocárdio/metabolismo , Difosfato de Adenosina/metabolismo , Trifosfato de Adenosina/metabolismo , Glicemia , Diabetes Mellitus Tipo 2/diagnóstico , Ácidos Graxos não Esterificados/sangue , Feminino , Hemoglobinas Glicadas/análise , Humanos , Concentração de Íons de Hidrogênio , Líquido Intracelular/metabolismo , Lipídeos/sangue , Espectroscopia de Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Oxigênio/metabolismo , Fosfocreatina/metabolismo , Isótopos de Fósforo/análise , Valores de Referência , Espectroscopia de Luz Próxima ao Infravermelho
17.
J Am Coll Cardiol ; 41(10): 1776-82, 2003 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-12767664

RESUMO

OBJECTIVES: We investigated cardiac energetics in subjects with mutations in three different familial hypertrophic cardiomyopathy (HCM) disease genes, some of whom were nonpenetrant carriers without hypertrophy, using phosphorus-31 magnetic resonance spectroscopy. BACKGROUND: Familial hypertrophic cardiomyopathy is caused by mutations in sarcomeric protein genes. The mechanism by which these mutant proteins cause disease is uncertain. A defect of myocyte contractility had been proposed, but in vitro studies of force generation have subsequently shown opposing results in different classes of mutation. An alternative hypothesis of "energy compromise" resulting from inefficient utilization of adenosine triphosphate (ATP) has been suggested, but in vivo data in humans with genotyped HCM are lacking. METHODS: The cardiac phosphocreatine (PCr) to ATP ratio was determined at rest in 31 patients harboring mutations in the genes for either beta-myosin heavy chain, cardiac troponin T, or myosin-binding protein C, and in 24 controls. Transthoracic echocardiography was used to measure left ventricular (LV) dimensions and maximal wall thickness. RESULTS: The PCr/ATP was reduced in the HCM subjects by 30% relative to controls (1.70 +/- 0.43 vs. 2.44 +/- 0.30; p < 0.001), and the reduction was of a similar magnitude in all three disease-gene groups. The PCr/ATP was equally reduced in subjects with (n = 24) and without (n = 7) LV hypertrophy. CONCLUSIONS: Our data provide evidence of a bioenergetic deficit in genotype-confirmed HCM, which is present to a similar degree in three disease-gene groups. The presence of energetic abnormalities, even in those without hypertrophy, supports a proposed link between altered cardiac energetics and development of the disease phenotype.


Assuntos
Miosinas Cardíacas/genética , Cardiomiopatia Hipertrófica/genética , Metabolismo Energético , Mutação , Miocárdio/metabolismo , Troponina T/genética , Trifosfato de Adenosina/metabolismo , Adolescente , Adulto , Idoso , Cardiomiopatia Hipertrófica/diagnóstico por imagem , Cardiomiopatia Hipertrófica/metabolismo , Proteínas de Transporte/genética , Criança , Ecocardiografia Transesofagiana , Feminino , Humanos , Espectroscopia de Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Mutação de Sentido Incorreto , Fosfocreatina/metabolismo , Miosinas Ventriculares/genética
18.
Ann Neurol ; 53(4): 533-7, 2003 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-12666123

RESUMO

Neurodevelopmental disorders could be caused by maternal antibodies or other serum factors. We detected serum antibodies binding to rodent Purkinje cells and other neurons in a mother of three children: the first normal, the second with autism, and the third with a severe specific language disorder. We injected the serum (0.5-1.0 ml/day) into pregnant mice during gestation and found altered exploration and motor coordination and changes in cerebellar magnetic resonance spectroscopy in the mouse offspring, comparing with offspring of mice injected with sera from mothers of healthy children. This evidence supports a role for maternal antibodies in some forms of neurodevelopmental disorder.


Assuntos
Transtorno Autístico/imunologia , Dislexia/imunologia , Imunidade Materno-Adquirida , Células de Purkinje/imunologia , Adulto , Animais , Criança , Feminino , Humanos , Imunoglobulina G/farmacologia , Imunoglobulina M/farmacologia , Imageamento por Ressonância Magnética , Espectroscopia de Ressonância Magnética , Masculino , Camundongos , Atividade Motora , Equilíbrio Postural , Gravidez
19.
NMR Biomed ; 16(1): 47-54, 2003 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-12577297

RESUMO

A two-dimensional COSY-based localization sequence was designed to allow the in vivo monitoring of proton metabolites in rat brain [particularly gamma-aminobutyric acid (GABA), glutamine, taurine and myo-inositol]. The sequence incorporated OSIRIS signal localization, B1-insensitive water suppression and phase-sensitive COSY acquisition. The method was used to study the effects of the GABA-transaminase inhibitor vigabatrin on rat brain metabolite concentrations. Wistar rats were treated daily for 3 days with an oral dose of vigabatrin (200 mg/kg, n = 4). Localized COSY spectra were obtained during a 120 min acquisition from a 270 microl central brain voxel and compared with nine untreated control animals. Significant elevations were observed in GABA (267% of control, p < 0.005, Mann-Witney test), glutamine (130% of control, p < 0.005) and taurine (113% of control, p < 0.05). Changes in GABA and taurine were consistent with previous data on the action of Vigabatrin, and support a previously hypothesized link between these compounds. The increase in glutamine was more surprising and may reflect the balance between the level and/or site of GABA-transaminase inhibition and downregulation of GABA synthesis.


Assuntos
Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Espectroscopia de Ressonância Magnética/métodos , Vigabatrina/farmacologia , Ácido gama-Aminobutírico/análise , Animais , Glutamina/análise , Glutamina/química , Glutamina/metabolismo , Masculino , Ratos , Ratos Wistar , Valores de Referência , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Taurina/análise , Taurina/química , Taurina/metabolismo , Ácido gama-Aminobutírico/química , Ácido gama-Aminobutírico/metabolismo
20.
Brain ; 125(Pt 11): 2446-59, 2002 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-12390971

RESUMO

TNF-alpha expression is elevated in a variety of neuropathologies, including multiple sclerosis, cerebral malaria and HIV encephalitis. However, the consequences of such high cerebral TNF-alpha expression remain unresolved. Here, using MRI, we demonstrate that a focal intrastriatal injection of TNF-alpha causes a significant, acute reduction (15-30%) in cerebral blood volume (CBV), which is dependent on TNF-alpha-type 2 receptor (TNFR2) activation, and can be ameliorated by pre-treatment with a non-specific endothelin (ET) receptor antagonist. An acute breakdown of the blood-cerebrospinal fluid barrier (B-CSF-B) and a delayed breakdown of the blood-brain barrier (BBB) were also observed using contrast-enhanced MRI. Furthermore, a significant reduction in tissue water diffusion was apparent 24 h after intrastriatal injection of TNF-alpha injection, which may indicate compromise of tissue energy metabolism. Prolonged expression of endogenous TNF-alpha, achieved through the use of an adenoviral vector expressing TNF-alpha cDNA (Ad5TNF-alpha(m)), caused a sustained depression in CBV in accordance with the single TNF-alpha bolus data. These findings identify vasoconstriction, disrupted tissue homeostasis and damage to the BBBs as adverse effects of TNF-alpha within the brain, and suggest that antagonists of the endothelin and TNF-alpha type 2 receptors may be therapeutic in TNF-alpha-associated neuropathologies.


Assuntos
Antígenos CD/metabolismo , Barreira Hematoencefálica/efeitos dos fármacos , Encéfalo/efeitos dos fármacos , Doenças do Sistema Nervoso Central/metabolismo , Circulação Cerebrovascular/efeitos dos fármacos , Endotelinas/metabolismo , Receptores do Fator de Necrose Tumoral/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Animais , Barreira Hematoencefálica/fisiologia , Encéfalo/metabolismo , Encéfalo/patologia , Doenças do Sistema Nervoso Central/tratamento farmacológico , Doenças do Sistema Nervoso Central/fisiopatologia , Líquido Cefalorraquidiano/efeitos dos fármacos , Líquido Cefalorraquidiano/metabolismo , Circulação Cerebrovascular/fisiologia , Esquema de Medicação , Endotelinas/antagonistas & inibidores , Metabolismo Energético/efeitos dos fármacos , Metabolismo Energético/fisiologia , Homeostase/efeitos dos fármacos , Homeostase/fisiologia , Imageamento por Ressonância Magnética , Masculino , Neostriado/efeitos dos fármacos , Neostriado/metabolismo , Neostriado/patologia , Ratos , Ratos Wistar , Receptores Tipo II do Fator de Necrose Tumoral , Proteínas Recombinantes de Fusão/farmacologia , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/fisiologia , Fator de Necrose Tumoral alfa/genética , Fator de Necrose Tumoral alfa/farmacologia , Equilíbrio Hidroeletrolítico/efeitos dos fármacos , Equilíbrio Hidroeletrolítico/fisiologia
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