Whole-Brain Magnetic Resonance Spectroscopy Reveals Distinct Alterations in Neurometabolic Profile in Progressive Supranuclear Palsy.

BACKGROUND: Progressive supranuclear palsy (PSP) is an atypical Parkinsonian syndrome characterized by supranuclear gaze palsy, early postural instability, and a frontal dysexecutive syndrome. Contrary to normal brain magnetic resonance imaging in Parkinson's disease (PD), PSP shows specific cerebral atrophy patterns and alterations, but these findings are not present in every patient, and it is still unclear if these signs are also detectable in early disease stages. OBJECTIVE: The aim of the present study was to analyze the metabolic profile of patients with clinically diagnosed PSP in comparison with matched healthy volunteers and PD patients using whole-brain magnetic resonance spectroscopic imaging (wbMRSI). METHODS: Thirty-nine healthy controls (HCs), 29 PD, and 22 PSP patients underwent wbMRSI. PSP and PD patients were matched for age and handedness with HCs. Clinical characterization was performed using the Movement Disorder Society Unified Parkinson's Disease Rating Scale, PSP rating scale, and DemTect (test for cognitive assessment). RESULTS: In PSP patients a significant reduction in N-acetyl-aspartate (NAA) was detected in all brain lobes. Fractional volume of the cerebrospinal fluid significantly increased in PSP patients compared to PD and healthy volunteers. CONCLUSIONS: In PSP much more neuronal degeneration and cerebral atrophy have been detected compared with PD. The most relevant alteration is the decrease in NAA in all lobes of the brain, which also showed a partial correlation with clinical symptoms. However, more studies are needed to confirm the additional value of wbMRSI in clinical practice. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Brain metabolic and microstructural alterations associated with hepatitis C virus infection, autoimmune hepatitis and primary biliary cholangitis.

BACKGROUND AND AIMS: Neuropsychiatric symptoms in hepatitis C (HCV) patients resemble those of patients with autoimmune hepatitis (AIH) or primary biliary cholangitis (PBC), whilst the mechanisms behind them are unknown. Here we looked for cerebral metabolic and/or microstructural alterations in patients with HCV, AIH or PBC as possible causes behind these symptoms. METHODS: Patients with HCV infection (n = 17), AIH (n = 14) or PBC (n = 11) and age-adjusted healthy controls (n = 18) underwent brain magnetic resonance imaging (MRI), magnetic resonance spectroscopy (MRS) and psychometric assessment of memory and attention. Brain relative proton density (PD) and T2 relaxation time (T2) were determined in 17 regions of interest (ROIs), as were the concentrations of N-acetyl-aspartate, choline, creatine, myo-inositol and glutamine + glutamate in frontal- (fWM) and parietal white matter (pWM). One-way analysis of variance and Kruskal-Wallis tests were used for group comparison. Correlations between altered neuropsychological findings and MRI/MRS observations were estimated with the Spearman ρ test. RESULTS: HCV, AIH and PBC patients revealed similar alterations in brain PD and metabolites compared to controls: significantly decreased PD in 7/17 ROIs in the HCV group, 16/17 ROIs in the PBC group and 14/17 ROIs in the AIH group, significantly increased N-acetyl-aspartate in fWM in all patients, significantly increased choline in the PBC group in both fWM and pWM, in the AIH group only in pWM and with a trend in the HCV group in pWM. Correlation analysis did not reveal significant associations between MRI/MRS alterations and neuropsychological dysfunction. CONCLUSION: The findings suggest similar pathophysiological mechanisms behind neuropsychiatric symptoms associated with HCV infection, AIH and PBC.

Reduced microglia activity in patients with long-term immunosuppressive therapy after liver transplantation.

PURPOSE: Calcineurin inhibitors (CNI) can cause long-term impairment of brain function. Possible pathomechanisms include alterations of the cerebral immune system. This study used positron emission tomography (PET) imaging with the translocator protein (TSPO) ligand 18F-GE-180 to evaluate microglial activation in liver-transplanted patients under different regimens of immunosuppression. METHODS: PET was performed in 22 liver-transplanted patients (3 CNI free, 9 with low-dose CNI, 10 with standard-dose CNI immunosuppression) and 9 healthy controls. The total distribution volume (VT) estimated in 12 volumes-of-interest was analyzed regarding TSPO genotype, CNI therapy, and cognitive performance. RESULTS: In controls, VT was about 80% higher in high affinity binders (n = 5) compared to mixed affinity binders (n = 3). Mean VT corrected for TSPO genotype was significantly lower in patients compared to controls, especially in patients in whom CNI dose had been reduced because of nephrotoxic side effect. CONCLUSION: Our results provide evidence of chronic suppression of microglial activity in liver-transplanted patients under CNI therapy especially in patients with high sensitivity to CNI toxicity.

Neuropsychiatric symptoms in hepatitis C patients resemble those of patients with autoimmune liver disease but are different from those in hepatitis B patients.

Chronic fatigue, mood alterations and cognitive impairment are frequent accessory symptoms of HCV infection. Fatigue and mood alterations have also been observed in autoimmune hepatitis (AIH) and primary biliary cholangitis (PBC), but not in hepatitis B virus (HBV)-infection, thus indicating an autoimmune response as possible cause of HCV infection-associated encephalopathy. Data, however, are sparse. This study aimed to prove that HCV patients feature similar to those with autoimmune liver disease but contrary to HBV patients regarding neuropsychiatric symptoms. A total of 132 noncirrhotic patients (HCV: 46, HBV: 22, AIH: 27, PBC: 29, AIH/PBC: 8) completed questionnaires addressing the domains mentioned above. Eighty-eight underwent a comprehensive neuropsychological assessment. Patient groups were compared among each other and to 33 healthy controls. Fatigue, anxiety and depression scores were significantly increased, and the SF-36 mental score significantly decreased in all patient groups compared to controls. Fatigue was significantly more pronounced in HCV than in HBV patients. HCV patients scored significantly worse than HBV patients but not AIH and PBC patients in the SF-36. HCV, AIH and PBC but not HBV patients did significantly worse than controls in word learning. Recognition of words was impaired in HCV, AIH and PBC patients and recognition of figures in HCV patients, exclusively (P ≤ 0.002). HCV patients did also worse than controls and HBV patients concerning alertness and working memory (P ≤ 0.001). The neuropsychiatric profiles of HCV patients are similar to those of AIH and PBC patients but differ from those of HBV patients, suggesting an autoimmune response as a possible cause for these differences.

Longterm calcineurin inhibitor therapy and brain function in patients after liver transplantation.

Calcineurin inhibitors (CNIs) frequently induce neurological complications early after orthotopic liver transplantation (OLT). We hypothesize that longterm CNI therapy after OLT causes dose-dependent cognitive dysfunction and alteration of brain structure. In this study, 85 OLT patients (20 with CNI-free, 35 with CNI low-dose, and 30 with standard-dose CNI immunosuppression) underwent psychometric testing and cerebral magnetic resonance imaging approximately 10 years after OLT to assess brain function and structural brain alterations. A total of 33 healthy patients adjusted for age, sex, and education served as controls. Patients receiving CNI showed a significantly worse visuospatial/constructional ability compared with controls (P ≤ 0.04). Furthermore, patients on low-dose CNI therapy had an overall impaired cognitive function compared with controls (P = 0.01). The tacrolimus total dose and mean trough level were negatively correlated to cognitive function. CNI doses had been adjusted in 91% of the patients in the low-dose and CNI-free groups in the past due to CNI-induced kidney damage. Patients treated with CNI showed significantly more white matter hyperintensities (WMH) than patients on CNI-free immunosuppression and controls (P < 0.05). Both the mean cyclosporine A and tacrolimus trough levels correlated significantly with WMH. In conclusion, longterm CNI therapy carries a risk of cognitive dysfunction especially in patients who already showed nephrotoxic side effects indicating an increased susceptibility of these patients against toxic CNI effects. This subgroup of patients might benefit from a change to CNI-free immunosuppression. Liver Transplantation 24 56-66 2018 AASLD.

Physiological neuronal decline in healthy aging human brain - An in vivo study with MRI and short echo-time whole-brain (1)H MR spectroscopic imaging.

Knowledge of physiological aging in healthy human brain is increasingly important for neuroscientific research and clinical diagnosis. To investigate neuronal decline in normal aging brain eighty-one healthy subjects aged between 20 and 70years were studied with MRI and whole-brain (1)H MR spectroscopic imaging. Concentrations of brain metabolites N-acetyl-aspartate (NAA), choline (Cho), total creatine (tCr), myo-inositol (mI), and glutamine+glutamate (Glx) in ratios to internal water, and the fractional volumes of brain tissue were estimated simultaneously in eight cerebral lobes and in cerebellum. Results demonstrated that an age-related decrease in gray matter volume was the largest contribution to changes in brain volume. Both lobar NAA and the fractional volume of gray matter (FVGM) decreased with age in all cerebral lobes, indicating that the decreased NAA was predominantly associated with decreased gray matter volume and neuronal density or metabolic activity. In cerebral white matter Cho, tCr, and mI increased with age in association with increased fractional volume, showing altered cellular membrane turn-over, energy metabolism, and glial activity in human aging white matter. In cerebellum tCr increased while brain tissue volume decreased with age, showing difference to cerebral aging. The observed age-related metabolic and microstructural variations suggest that physiological neuronal decline in aging human brain is associated with a reduction of gray matter volume and neuronal density, in combination with cellular aging in white matter indicated by microstructural alterations and altered energy metabolism in the cerebellum.

Reproducibility and reliability of short-TE whole-brain MR spectroscopic imaging of human brain at 3T.

PURPOSE: A feasibility study of an echo-planar spectroscopic imaging (EPSI) using a short echo time (TE) that trades off sensitivity, compared with other short-TE methods, to achieve whole brain coverage using inversion recovery and spatial oversampling to control lipid bleeding. METHODS: Twenty subjects were scanned to examine intersubject variance. One subject was scanned five times to examine intrasubject reproducibility. Data were analyzed to determine coefficients of variance (COV) and intraclass correlation coefficient (ICC) for N-acetylaspartate (NAA), total creatine (tCr), total choline (tCho), glutamine/glutamate (Glx), and myo-inositol (mI). Regional metabolite concentrations were derived by using multi-voxel analysis based on lobar-level anatomic regions. RESULTS: For whole-brain mean values, the intrasubject COVs were 14%, 15%, and 20% for NAA, tCr, and tCho, respectively, and 31% for Glx and mI. The intersubject COVs were up to 6% higher. For regional distributions, the intrasubject COVs were ≤ 5% for NAA, tCr, and tCho; ≤ 9% for Glx; and ≤15% for mI, with about 6% higher intersubject COVs. The ICCs of 5 metabolites were ≥ 0.7, indicating the reliability of the measurements. CONCLUSION: The present EPSI method enables estimation of the whole-brain metabolite distributions, including Glx and mI with small voxel size, and a reasonable scan time and reproducibility.

Cerebral white matter lesions in patients with cirrhosis - causative for hepatic encephalopathy or bystanders?

BACKGROUND & AIMS: Focal white matter lesions mimicking microvascular lesions were connected to the development of hepatic encephalopathy (HE) in patients with cirrhosis. This study aims to assess the relationship between cerebrovascular risk factors and the prevalence and extent of these lesions in patients with cirrhosis, as well as their impact upon cognitive function. METHODS: 55 cirrhotic patients underwent neurological examination, psychometric testing and magnetic resonance imaging. T2-weighted images were reviewed for white matter lesions by a neuroradiologist and a neurologist, independently. Patients were allocated into three groups: (i) no or <5, (ii) 6-15 and (iii) more than 15 lesions. Allocation was confirmed by a senior neuroradiologist blinded for the clinical data. The patient groups were compared concerning age, underlying liver disease, mortality, MELD Score, history of HE, treatment for HE, cerebrovascular risk factors and psychometric test results. Regression analysis was performed to identify risk factors for the presence and extent of white matter lesions. RESULTS: Patient groups 2 and 3 were older and showed worse results in the psychometric tests than group 1 (P < 0.05). Correlation analyses showed a significant relationship between the number of white matter lesions and the grade of HE (P < 0.001) and cognitive function (P < 0.05), but no interrelationship between the lesions and cerebrovascular risk factors or other factors tested. CONCLUSIONS: Focal white matter lesions in patients with cirrhosis do not represent cerebrovascular small-vessel disease but are related to the pathology of HE. Further studies are needed to clarify the mechanisms behind in detail.

Identification of a Novel Chitinase from Bacillus paralicheniformis: Gene Mining, Sequence Analysis, and Enzymatic Characterization.

In this study, a novel strain for degrading chitin was identified as Bacillus paralicheniformis HL37, and the key chitinase CH1 was firstly mined through recombinant expression in Bacillus amyloliquefaciens HZ12. Subsequently, the sequence composition and catalytic mechanism of CH1 protein were analyzed. The molecular docking indicated that the triplet of Asp526, Asp528, and Glu530 was a catalytic active center. The enzymatic properties analysis revealed that the optimal reaction temperature and pH was 65 °C and 6.0, respectively. Especially, the chitinase activity showed no significant change below 55 °C and it could maintain over 60% activity after exposure to 85 °C for 30 min. Moreover, the optimal host strain and signal peptide were obtained to enhance the expression of chitinase CH1 significantly. As far as we know, it was the first time finding the highly efficient chitin-degrading enzymes in B. paralicheniformis, and detailed explanations were provided on the catalytic mechanism and enzymatic properties on CH1.

Quantitative MRI shows cerebral microstructural damage in hemolytic-uremic syndrome patients with severe neurological symptoms but no changes in conventional MRI.

INTRODUCTION: Severe neurological symptoms in Shiga toxin-producing Escherichia coli infection associated hemolytic-uremic syndrome (STEC-HUS) are often accompanied by none or only mild alterations of cerebral magnetic resonance imaging (MRI). This study aims to analyze if quantitative MRI is able to reveal cerebral pathological alterations invisible for conventional MRI. METHODS: In nine patients with STEC-HUS associated severe neurological symptoms but inconspicuous cerebral MRI findings maps of the parameters T2 relaxation time, relative proton density (PD), apparent diffusion coefficient (ADC), and fractional anisotropy (FA) were generated. Quantitative values of these parameters were measured at the basal ganglia, thalamus, and white matter of the frontal and parietal lobe and compared to those of nine age- and sex-matched controls. RESULTS: Significant T2 prolongation (p < 0.01) was found in the basal ganglia of all patients compared to controls. PD and ADC were not significantly altered. A significant reduction of FA in patients was seen at caput nuclei caudati (p < 0.01). CONCLUSION: Prolonged T2 relaxation time indicates cerebral microstructural damages in these patients despite their inconspicuous MRI findings. T2 relaxometry could be used as a complementary tool for the assessment of metabolic-toxic brain syndromes.

Effects of an eastward shift in the Agulhas retroflection region on chlorophyll-a bloom on its south flank.

As observed by remote sensing images in December 2013 and January 2014, chlorophyll-a (Chl-a) bloom occurred on the south side of the Agulhas Current (38°S-45°S). The dynamic mechanisms of Chl-a bloom were studied by satellite remote sensing data, reanalysis data and Argo data. The periodic shedding of the Agulhas ring led to a significant eastward shift of the Agulhas retroflection from December 2013 to January 2014, without the obstruction of flowing complex eddies and with increased current flow. Then, the horizontal transfer of Chl-a occurred along the south side of the Agulhas Current (38°S-45°S). Nitrate concentrations reached 10-15 µmol·L-1 on the south side of the Agulhas Current, where a deepened mixed layer and upwelling and the vertical transport of nutrients contributed to the Chl-a bloom. In addition, sufficient light and suitable precipitation provide good conditions for Chl-a bloom on the south side of the Agulhas Current.

Effects of Tropical Cyclone (TC) Hellen on the north-westward movement of chlorophyll in the northern Mozambique Channel.

An intense tropical cyclone (TC), TC Hellen, occurred in the northern Mozambique Channel on March 27, 2014, and moved from the east coast of the African continent to the northern Madagascar island. TC Hellen dramatically altered the marine environment in the northern Mozambique Channel, resulting in a significant chlorophyll-a (Chl-a) bloom. A giant surface Chl-a northwest-ward movement from the northwest coast of Madagascar Island was first observed after the passage of TC Hellen in the northern Mozambique Channel. The dynamic mechanisms of these phenomenon were studied by satellite remote sensing, multisource reanalysis data, and Argo float data. The results show that transient northwestward-moving eddies, upwelling, and winds had important effects on the Chl-a bloom and its northwestward movement. Ekman transport driven by coastal southeasterly winds entrained waters with high Chl-a concentrations to the northwest, while TC Hellen enhanced cyclonic eddy upwelling and uplifted nutrient-rich deep water to the upper ocean. This vertical mixing and upwelling in turn triggered the Chl-a bloom in the offshore surface layer. This study provides insight into the reflection of phytoplankton dynamics by TCs in the northern Mozambique Channel.

Systematic investigation of the emerging pathogen of Tsukamurella species in a Chinese tertiary teaching hospital.

Tsukamurella species have been clinically regarded as rare but emerging opportunistic pathogens causing various infections in humans. Tsukamurella pneumonia has often been misdiagnosed as pulmonary tuberculosis due to its clinical presentation resembling tuberculosis-like syndromes. Tsukamurella species have also been confused in the laboratory with other phylogenetic bacteria, such as Gordonia. This study aimed to investigate the clinical, microbiological, and molecular characteristics; species distribution; and antimicrobial susceptibility of Tsukamurella species. Immunodeficiency and chronic pulmonary disease appeared to be risk factors for Tsukamurella pneumonia, and the presence of bronchiectasis and pulmonary nodules on imaging was highly correlated with this infection. The study confirmed that groEL (heat shock protein 60) and secA (the secretion ATPase) genes are reliable for identifying Tsukamurella species. Additionally, the ssrA (stable small RNA) gene showed promise as a tool for discriminating between different Tsukamurella species with the shortest sequence length. In terms of antimicrobial susceptibility, quinolones, trimethoprim/sulfamethoxazole, amikacin, minocycline, linezolid, and tigecycline demonstrated potent in vitro activity against Tsukamurella isolates in our study. The study also proposed a resistance mechanism involving a substitution (S91R) within the quinolone-resistance-determining region of the gyrA gene, which confers resistance to levofloxacin and ciprofloxacin. Furthermore, we found that disk diffusion testing is not suitable for testing the susceptibilities of Tsukamurella isolates to ciprofloxacin, imipenem, and minocycline. In conclusion, our systematic investigation may contribute to a better understanding of this rare pathogen. Tsukamurella species are rare but emerging human pathogens that share remarkable similarities with other mycolic acid-containing genera of the order Actinomycetales, especially Mycobacterium tuberculosis. Consequently, misdiagnosis and therapeutic failures can occur in clinical settings. Despite the significance of accurate identification, antimicrobial susceptibility, and understanding the resistance mechanism of this important genus, our knowledge in these areas remains fragmentary and incomplete. In this study, we aimed to address these gaps by investigating promising identification methods, the antimicrobial susceptibility patterns, and a novel quinolone resistance mechanism in Tsukamurella species, utilizing a collection of clinical isolates. The findings of our study will contribute to improve diagnosis and successful management of infections caused by Tsukamurella species, as well as establishing well-defined performance and interpretive criteria for antimicrobial susceptibility testing.

A novel positron emission tomography imaging protocol identifies seizure-induced regional overactivity of P-glycoprotein at the blood-brain barrier.

Approximately one-third of epilepsy patients are pharmacoresistant. Overexpression of P-glycoprotein and other multidrug transporters at the blood-brain barrier is thought to play an important role in drug-refractory epilepsy. Thus, quantification of regionally different P-glycoprotein activity in the brain in vivo is essential to identify P-glycoprotein overactivity as the relevant mechanism for drug resistance in an individual patient. Using the radiolabeled P-glycoprotein substrate (R)-[(11)C]verapamil and different doses of coadministered tariquidar, which is an inhibitor of P-glycoprotein, we evaluated whether small-animal positron emission tomography can quantify regional changes in transporter function in the rat brain at baseline and 48 h after a pilocarpine-induced status epilepticus. P-glycoprotein expression was additionally quantified by immunohistochemistry. To reveal putative seizure-induced changes in blood-brain barrier integrity, we performed gadolinium-enhanced magnetic resonance scans on a 7.0 tesla small-animal scanner. Before P-glycoprotein modulation, brain uptake of (R)-[(11)C]verapamil was low in all regions investigated in control and post-status epilepticus rats. After administration of 3 mg/kg tariquidar, which inhibits P-glycoprotein only partially, we observed increased regional differentiation in brain activity uptake in post-status epilepticus versus control rats, which diminished after maximal P-glycoprotein inhibition. Regional increases in the efflux rate constant k(2), but not in distribution volume V(T) or influx rate constant K(1), correlated significantly with increases in P-glycoprotein expression measured by immunohistochemistry. This imaging protocol proves to be suitable to detect seizure-induced regional changes in P-glycoprotein activity and is readily applicable to humans, with the aim to detect relevant mechanisms of pharmacoresistance in epilepsy in vivo.

Imaging evidence of early brain tissue degeneration in patients with vanishing white matter disease: a multimodal MR study.

To find imaging signs of active degenerative processes in vanishing white matter disease (VWM), six VWM patients and six matched controls underwent MR examinations. The data were analyzed with modified Scheltens scales for morphological findings and determined quantitatively for apparent diffusion coefficient (ADC). Single-voxel MR spectra were acquired at the parietal white matter and analyzed with LCModel. Typical VWM brain lesions were found in all patients accompanied by proton diffusion abnormalities: Increased ADC appeared in brain regions with severe myelin destruction in all patients, and reduced ADC in two of six younger patients in remaining white matter adjacent to the lesions or at the borders around the lesions, who had a short history of the disease (≤ 1 year). The MR spectroscopy revealed reductions of NAA, Cho, and Cr, which correlate to the grade of white matter abnormalities. An increase of myo-inositol as marker of reactive gliosis was missing. Thus, restricted proton diffusion was evident in younger VWM patients with short history of disease, which in combination with lack of reactive gliosis may reflect early white matter degeneration in VWM. The multimodal MR methods are useful for characterizing such tissue degeneration in brain in vivo.

Patterns in early diffusion-weighted MRI in children with haemolytic uraemic syndrome and CNS involvement.

OBJECTIVES: Diffusion-weighted imaging (DWI) in children with diarrhoea associated haemolytic uraemic syndrome (D+HUS) and cerebral involvement was evaluated retrospectively. METHODS: DWI within 24 h of onset of neurological symptoms. The apparent diffusion coefficient (ADC) was measured in grey/white matter and correlated with clinical and laboratory findings. RESULTS: DWI was abnormal in all. Abnormal ADC was detected in the supratentorial white matter (6/12) and cortex (1/12), the basal ganglia (5/12), the thalami (4/12), and the cerebellum (1/12). ADC was reduced in 5/12, increased in 4/12, and both in 3/12. Mean serum sodium was lower in patients with DWI abnormalities affecting the white matter (6/12), than in those with basal ganglia/thalamic involvement (6/12). Neurological outcome was normal in 4/11 and abnormal in 7/11, and 1 patient died, outcome did not correlate to either localisation or type of DWI abnormality. CONCLUSIONS: In D+HUS with neurological symptoms, early DWI may reveal abnormal ADC not only in the basal ganglia/thalami, but also in the white matter/cortex. Besides thrombotic microangiopathy, toxic effects of shiga toxin, azotaemia and hyponatraemia / hypoosmolality may be involved in cerebral involvement in children with D+HUS. Findings on early MRI seem not to predict clinical course or outcome. KEY POINTS: • DWI MR imaging may detect early CNS involvement in haemolytic uraemic syndrome • Different pathogenetical mechanisms may contribute to the CNS disease in HUS • Early MRI findings do not seem to allow prediction of clinical outcome.

Impact of fasting on stress systems and depressive symptoms in patients with major depressive disorder: a cross-sectional study.

Major depressive disorder (MDD) is frequently associated with poor response to treatment. Common antidepressants target neurotransmission and neuronal plasticity, which require adequate energy supply. As imaging studies indicate disturbances in central energy metabolism, and caloric restriction improves neuroplasticity and impacts mood and cognition, correction of energy status might increase the effectiveness of antidepressant treatments and reduce the psychopathological symptoms of depression. Metabolic parameters, stress hormones, and brain-derived neurotrophic factor (BDNF) levels were assessed in serum of depressed inpatients (MDD, N = 21) and healthy volunteers (Ctrl, N = 28) before and after a 72 h fasting period during which only water was consumed. Depression severity was assessed by Beck's Depression Inventory (BDI)-2 sum-score and cognitive-affective and somatic sub-scores. Fasting similarly impacted metabolic parameters and stress systems in both groups. Fasting elevated BDI-2 sum-scores and somatic sub-scores in Ctrl. In MDD, fasting increased somatic-, but decreased cognitive-affective symptoms. Sub-group analyses based on BDI-2 sum-scores pre-fasting showed that cognitive-affective symptoms decreased in patients with moderate/severe but not in those with mild symptoms. This was associated with differential changes in BDNF levels. In conclusion, fasting improved cognitive-affective sub-scores in MDD patients with moderate/severe symptoms that had not responded to prior therapy. Interventions that modulate energy metabolism might directly improve cognitive-affective symptoms and/or augment therapeutic efficacy in moderate-to-severely depressed patients.

Value of quantitative analysis of routine clinical MRI sequences in ALS.

Simple morphological assessment of conventional MRI used in routine neurological diagnostic work-up lacks sensitivity and specificity for amyotrophic lateral sclerosis (ALS). Quantitative analysis of routine MRI sequences might, however, be more suitable to reveal ALS-related pathological cerebral alterations. We investigated 10 ALS patients and 10 age- and sex-matched healthy controls by MRI. Brain maps of T2 relaxation time (T2), relative proton density (PD), and apparent diffusion coefficient (ADC) were obtained. Values of these parameters were measured in 22 selected brain regions, and compared among the patients and the controls by using paired t-test with Bonferroni corrected alpha level (= 0.002). In ALS patients, increased PD was found in the pyramidal tract, corpus callosum, and white and grey matter. T2 elongation was found at the genu of corpus callosum, and at the posterior limb of the internal capsule (ICP). ADC values showed a tendency towards an increase in patients, which was only significant at the ICP. PD therefore appeared to be the most sensitive parameter for the detection of degenerative changes not only in the motor system but also in extramotor brain regions.

Macromolecule content influences proton diffusibility in gliomas.

OBJECTIVES: Different compositions of the extra cellular matrix with changing concentrations of more or less hydrophilic components like proteins may have a major influence on the diffusion phenomena found in gliomas. METHODS: 24 patients (14 male / 10 female) with histologically confirmed non necrotic glioma underwent preoperative MRI, including magnetisation transfer (MTR), triple echo T2 weighted (T2W) and diffusion weighted (DWI) sequences. Apparent diffusion coefficient (ADC), quantitative T2 and MTR maps were calculated and regions of interest (ROIs) were placed in the tumour centre (TU) and in the contralateral hemisphere (NWM). Informed consent was obtained. The study was approved by the local ethic comity. RESULTS: Mean values evaluated in the NWM / TU were (± standard deviation); ADC: 0.78 (±0.08) × 10-3 mm2/s / 1.32 (±0.27) × 10-3 mm2/s, T2: 101.66 (±12.00) ms / 252.11 (±104.53) ms, MTR: 0.52 (±0.01) / 0.40 (±0.04). The mean value of each parameter correlated highly significant with the others (p < 0.01). CONCLUSION: Our results suggest that macromolecules binding protons in their vicinity are a major determinant of proton diffusivity in brain tumours in addition to other factors such as mechanical barriers like membranes or the size of the extra-cellular space.

Alterations of Striato-Thalamic Metabolism in Normal Aging Human Brain-An MR Metabolic Imaging Study.

Aging effects on striato-thalamic metabolism in healthy human brains were studied in vivo using short-TE whole brain 1H-MR spectroscopic imaging (wbMRSI) on eighty healthy subjects aged evenly between 20 to 70 years at 3T. Relative concentrations of N-acetyl-aspartate (NAA), choline, total creatine (tCr), myo-inositol (mI), glutamate, and glutamine in bilateral caudate nucleus, putamen, pallidum, and thalamus were determined using signal normalization relative to brain tissue water. Linear regression analysis was used to analyze the age-dependence of the metabolite concentrations. The metabolite concentrations revealed spatial inhomogeneity across brain regions and metabolites. With age, NAA decreased significantly in bilateral caudate nucleus and putamen, left pallidum, and left thalamus, tCr decreased in left putamen and bilateral pallidum, mI increased in bilateral caudate nucleus and right thalamus, and spectral linewidth increased in left putamen and right thalamus. In conclusion, normal aging of striato-thalamic metabolism in healthy human is associated with regional specific decreases of NAA and tCr and increases of mI, which may reflect the individual role of each brain structure within brain functionality.