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1.
AJNR Am J Neuroradiol ; 44(4): 424-433, 2023 04.
Article in English | MEDLINE | ID: mdl-36927760

ABSTRACT

BACKGROUND AND PURPOSE: Superagers are defined as older adults with episodic memory performance similar or superior to that in middle-aged adults. This study aimed to investigate the key differences in discriminative networks and their main nodes between superagers and cognitively average elderly controls. In addition, we sought to explore differences in sensitivity in detecting these functional activities across the networks at 3T and 7T MR imaging fields. MATERIALS AND METHODS: Fifty-five subjects 80 years of age or older were screened using a detailed neuropsychological protocol, and 31 participants, comprising 14 superagers and 17 cognitively average elderly controls, were included for analysis. Participants underwent resting-state-fMRI at 3T and 7T MR imaging. A prediction classification algorithm using a penalized regression model on the measurements of the network was used to calculate the probabilities of a healthy older adult being a superager. Additionally, ORs quantified the influence of each node across preselected networks. RESULTS: The key networks that differentiated superagers and elderly controls were the default mode, salience, and language networks. The most discriminative nodes (ORs > 1) in superagers encompassed areas in the precuneus posterior cingulate cortex, prefrontal cortex, temporoparietal junction, temporal pole, extrastriate superior cortex, and insula. The prediction classification model for being a superager showed better performance using the 7T compared with 3T resting-state-fMRI data set. CONCLUSIONS: Our findings suggest that the functional connectivity in the default mode, salience, and language networks can provide potential imaging biomarkers for predicting superagers. The 7T field holds promise for the most appropriate study setting to accurately detect the functional connectivity patterns in superagers.


Subject(s)
Gyrus Cinguli , Magnetic Resonance Imaging , Aged , Middle Aged , Humans , Magnetic Resonance Imaging/methods , Cognition , Prefrontal Cortex , Temporal Lobe , Brain Mapping/methods , Brain/diagnostic imaging
2.
AJNR Am J Neuroradiol ; 42(10): 1790-1797, 2021 10.
Article in English | MEDLINE | ID: mdl-34446458

ABSTRACT

BACKGROUND AND PURPOSE: Youthful memory performance in older adults may reflect an underlying resilience to the conventional pathways of aging. Subjects having this unusual characteristic have been recently termed "superagers." This study aimed to explore the significance of imaging biomarkers acquired by 1H-MRS to characterize superagers and to differentiate them from their normal-aging peers. MATERIALS AND METHODS: Fifty-five patients older than 80 years of age were screened using a detailed neuropsychological protocol, and 25 participants, comprising 12 superagers and 13 age-matched controls, were statistically analyzed. We used state-of-the-art 3T 1H-MR spectroscopy to quantify 18 neurochemicals in the posterior cingulate cortex of our subjects. All 1H-MR spectroscopy data were analyzed using LCModel. Results were further processed using 2 approaches to investigate the technique accuracy: 1) comparison of the average concentration of metabolites estimated with Cramer-Rao lower bounds <20%; and 2) calculation and comparison of the weighted means of metabolites' concentrations. RESULTS: The main finding observed was a higher total N-acetyl aspartate concentration in superagers than in age-matched controls using both approaches (P = .02 and P = .03 for the weighted means), reflecting a positive association of total N-acetyl aspartate with higher cognitive performance. CONCLUSIONS: 1H-MR spectroscopy emerges as a promising technique to unravel neurochemical mechanisms related to cognitive aging in vivo and providing a brain metabolic signature in superagers. This may contribute to monitoring future interventional therapies to avoid or postpone the pathologic processes of aging.


Subject(s)
Brain Mapping , Brain , Aged , Brain/diagnostic imaging , Cognition , Humans , Pilot Projects , Proton Magnetic Resonance Spectroscopy
3.
AJNR Am J Neuroradiol ; 42(5): 961-968, 2021 05.
Article in English | MEDLINE | ID: mdl-33664107

ABSTRACT

BACKGROUND AND PURPOSE: Primary posterior fossa tumors comprise a large group of neoplasias with variable aggressiveness and short and long-term outcomes. This study aimed to validate the clinical usefulness of a radiologic decision flow chart based on previously published neuroradiologic knowledge for the diagnosis of posterior fossa tumors in children. MATERIALS AND METHODS: A retrospective study was conducted (from January 2013 to October 2019) at 2 pediatric referral centers, Children's Hospital of Philadelphia, United States, and Great Ormond Street Hospital, United Kingdom. Inclusion criteria were younger than 18 years of age and histologically and molecularly confirmed posterior fossa tumors. Subjects with no available preoperative MR imaging and tumors located primarily in the brain stem were excluded. Imaging characteristics of the tumors were evaluated following a predesigned, step-by-step flow chart. Agreement between readers was tested with the Cohen κ, and each diagnosis was analyzed for accuracy. RESULTS: A total of 148 cases were included, with a median age of 3.4 years (interquartile range, 2.1-6.1 years), and a male/female ratio of 1.24. The predesigned flow chart facilitated identification of pilocytic astrocytoma, ependymoma, and medulloblastoma sonic hedgehog tumors with high sensitivity and specificity. On the basis of the results, the flow chart was adjusted so that it would also be able to better discriminate atypical teratoid/rhabdoid tumors and medulloblastoma groups 3 or 4 (sensitivity = 75%-79%; specificity = 92%-99%). Moreover, our adjusted flow chart was useful in ruling out ependymoma, pilocytic astrocytomas, and medulloblastoma sonic hedgehog tumors. CONCLUSIONS: The modified flow chart offers a structured tool to aid in the adjunct diagnosis of pediatric posterior fossa tumors. Our results also establish a useful starting point for prospective clinical studies and for the development of automated algorithms, which may provide precise and adequate diagnostic tools for these tumors in clinical practice.


Subject(s)
Algorithms , Infratentorial Neoplasms/diagnosis , Magnetic Resonance Imaging/methods , Adolescent , Child , Child, Preschool , Female , Humans , Infant , Infratentorial Neoplasms/pathology , Male
4.
Transl Psychiatry ; 7(4): e1086, 2017 04 11.
Article in English | MEDLINE | ID: mdl-28398341

ABSTRACT

Calcium channels control the inflow of calcium ions into cells and are involved in diverse cellular functions. The CACNA1C gene polymorphism rs1006737 A allele has been strongly associated with increased risk for bipolar disorder (BD) and with modulation of brain morphology. The medial prefrontal cortex (mPFC) has been widely associated with mood regulation in BD, but the role of this CACNA1C polymorphism in mPFC morphology and brain aging has yet to be elucidated. One hundred seventeen euthymic BD type I subjects were genotyped for CACNA1C rs1006737 and underwent 3 T three-dimensional structural magnetic resonance imaging scans to determine cortical thickness of mPFC components (superior frontal cortex (sFC), medial orbitofrontal cortex (mOFC), caudal anterior cingulate cortex (cACC) and rostral anterior cingulate cortex (rACC)). Carriers of the CACNA1C allele A exhibited greater left mOFC thickness compared to non-carriers. Moreover, CACNA1C A carriers showed age-related cortical thinning of the left cACC, whereas among A non-carriers there was not an effect of age on left cACC cortical thinning. In the sFC, mOFC and rACC (left or right), a negative correlation was observed between age and cortical thickness, regardless of CACNA1C rs1006737 A status. Further studies investigating the direct link between cortical thickness, calcium channel function, apoptosis mechanism and their underlying relationship with aging-associated cognitive decline in BD are warranted.


Subject(s)
Alleles , Bipolar Disorder/genetics , Bipolar Disorder/pathology , Calcium Channels, L-Type/genetics , Genetic Predisposition to Disease/genetics , Prefrontal Cortex/pathology , Adolescent , Adult , Age Factors , Bipolar Disorder/diagnostic imaging , Dominance, Cerebral/genetics , Dominance, Cerebral/physiology , Female , Genetic Carrier Screening , Humans , Imaging, Three-Dimensional , Magnetic Resonance Imaging , Male , Polymorphism, Genetic/genetics , Prefrontal Cortex/diagnostic imaging , Statistics as Topic , Young Adult
5.
Nutr Hosp ; 26(2): 415-20, 2011.
Article in English | MEDLINE | ID: mdl-21666983

ABSTRACT

OBJECTIVES: To evaluate the effect of flaxseed upon body growth and brain of rats. METHODS: Experimental phase lasted 52 days, using 42 Wistar rats which were divided into four groups: Control (CG, n = 12), 10% casein diet; Flaxseed (GL, n = 12), 10% flaxseed diet plus casein; Modified Control (GCM, n = 12), 10% casein diet with changes in lipid and fiber comparable to GL; Non-protein (GA, n = 6), diet without protein. Considering food intake, protein intake and weight variation, the Protein Efficiency Ratio (PER) was calculated. Net Protein Retention (NPR) and the Food Efficiency Ratio (CEA) were also determined relative to brain weight at 30 days of life (M30) and at 52 days (M52). Analysis of Variance (ANOVA), Test of Sheffe and post-test of Bonferroni were used, p < 0.05. RESULTS: GL had lower food intake, protein and weight variation than GC, but had higher values than GCM. Concerning PER, GL was lower than GC and similar to the GCM, as well as CEA. As for NPR, GL had lower values than the CG and GCM. At M30, GL was superior to GC in relation to brain weight. Likewise, the same was observed at M52. CONCLUSION: Flaxseed promoted adequate growth and better brain development in animals, which might be explained by increased incorporation of omega-3 into these tissues.


Subject(s)
Brain/growth & development , Flax , Growth/drug effects , Animals , Body Weight/physiology , Brain/drug effects , Brain Chemistry , Diet , Dietary Proteins/administration & dosage , Dietary Proteins/analysis , Eating , Fatty Acids, Omega-3/pharmacology , Organ Size/drug effects , Rats , Rats, Wistar
6.
Br J Radiol ; 83(989): 437-46, 2010 May.
Article in English | MEDLINE | ID: mdl-20223908

ABSTRACT

Wernicke's encephalopathy (WE) is a serious neurological disorder secondary to thiamine deficiency. Improved recognition by radiologists and allied health providers of the different clinical settings and imaging findings associated with this emergency can optimise the management of this condition and help prevent its severe consequences. The aim of this study is to illustrate the broad clinicoradiological spectrum of non-alcoholic WE, while emphasising atypical MRI findings.


Subject(s)
Thiamine Deficiency/diagnosis , Wernicke Encephalopathy/diagnosis , Adolescent , Adult , Contrast Media , Female , Humans , Magnetic Resonance Imaging/methods , Male , Middle Aged , Thiamine Deficiency/complications , Wernicke Encephalopathy/etiology
7.
Neuroradiol J ; 23(5): 554-73, 2010 Oct.
Article in English | MEDLINE | ID: mdl-24148677

ABSTRACT

Infectious diseases of the central nervous system vary in frequency in different locations in America and Europe. What is common in Brazil can be a sporadic presentation in Europe. Cooperative work gathering experiences from neuroradiologists working in various places can be achieved and will help to identify uncommon cases that can present in our daily practice.

9.
Neurology ; 62(7): 1206-9, 2004 Apr 13.
Article in English | MEDLINE | ID: mdl-15079028

ABSTRACT

We describe three cases of the rare syndrome of leukoencephalopathy, brain calcifications, and cysts. Conventional MRI, proton spectroscopy, and diffusion-weighted imaging yielded additional information on the disease. Imaging findings favor increased water content rather than a demyelinating process in the pathophysiology of this disease. Clinical features of Coats disease and consanguinity were also encountered.


Subject(s)
Aspartic Acid/analogs & derivatives , Brain Diseases/diagnosis , Brain/pathology , Calcinosis/diagnosis , Central Nervous System Cysts/diagnosis , Retinal Diseases/diagnosis , Adolescent , Aspartic Acid/metabolism , Brain/metabolism , Brain Diseases/complications , Brain Diseases/pathology , Calcinosis/complications , Central Nervous System Cysts/complications , Child , Choline/metabolism , Creatine/metabolism , Diffusion Magnetic Resonance Imaging , Disease Progression , Female , Humans , Lactic Acid/metabolism , Magnetic Resonance Imaging , Magnetic Resonance Spectroscopy , Male , Rare Diseases/diagnosis , Retinal Diseases/complications , Syndrome , Tomography, X-Ray Computed
10.
Can J Microbiol ; 50(9): 767-70, 2004 Sep.
Article in English | MEDLINE | ID: mdl-15644931

ABSTRACT

A vancomycin-resistant Enterococcus (VRE) was isolated from a blood culture of a patient in a Brazilian hospital who had a treatment history of a bone marrow transplant in the USA. The organism was identified as Enterococcus faecium, which exhibited an MIC (minimum inhibitory concentration) >or= 256 microg/mL for vancomycin. This was confirmed by E-test and the vanA gene was detected by PCR. Overlapping PCR revealed a left IR deletion and an additional 1.5 kb fragment between vanSH genes. DdeI digestion of vanRSHAX genes showed the determinant to be a T type variant, and the element was cloned and sequenced. These results revealed an IS1251 downstream of nucleotide 5820 of the VanA element. Insertions like this have not been reported previously in Brazil, but have been detected in the USA. The genotype and association with a patient previously treated in the USA suggest that this VRE was introduced from abroad, probably through inter-hospital strain spread.


Subject(s)
Bacterial Proteins/genetics , Carbon-Oxygen Ligases/genetics , Enterococcus faecium/classification , Transportation of Patients , Vancomycin Resistance , Aged , Bone Marrow Transplantation/adverse effects , Brazil , DNA Transposable Elements , Enterococcus faecium/drug effects , Enterococcus faecium/genetics , Female , Gram-Positive Bacterial Infections/microbiology , Humans , Microbial Sensitivity Tests , Molecular Sequence Data , Sequence Analysis, DNA , United States
11.
J Microbiol Methods ; 37(3): 223-9, 1999 Sep.
Article in English | MEDLINE | ID: mdl-10480266

ABSTRACT

Polymerase chain reaction amplification of part of the gene coding for the heat shock protein hsp65 followed by restriction enzyme analysis (PRA) is a recently described tool for rapid identification of mycobacteria. In this study, the speed and simplicity of PRA for identification of isolates of mycobacteria from patients with clinical symptoms of tuberculosis was evaluated and compared with identification results obtained by commercially available methods. Established PRA patterns were observed for nineteen isolates of Mycobacterium tuberculosis, eleven belonging to the complex M. avium-intracellulare, four of M. kansasii, one of M. fortuitum, one of M. abscessus, three of M. gordonae and one of the recently described species M. lentiflavum, as identified by commercially available methods. Two isolates of M. fortuitum and one of M. gordonae had unique and so far undescribed PRA patterns, suggesting geographically-related intra-species variation within the hsp65 sequence. We propose the inclusion of these new patterns in the PRA identification algorithm and have defined more accurately the molecular weight values of the restriction fragments. This is the first report on the isolation of M. lentiflavum in Brazil suggesting that identification by means of PRA could be useful for detection of mycobacterial species that are usually unnoticed. Where the use of several commercial techniques in combination was necessary for correct identification, PRA demonstrated to be a simple technique with good cost-benefit for characterization of all mycobacterial isolates in this study.


Subject(s)
Bacterial Proteins , Chaperonins/genetics , Mycobacterium Infections/microbiology , Mycobacterium/classification , Polymerase Chain Reaction/methods , Polymorphism, Restriction Fragment Length , Brazil , Chaperonin 60 , DNA, Bacterial/analysis , Deoxyribonucleases, Type II Site-Specific/metabolism , Humans , Image Processing, Computer-Assisted/methods , Molecular Sequence Data , Mycobacterium/genetics , Tuberculosis/microbiology
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