Longitudinally consistent estimates of intrinsic functional networks

Increasing numbers of neuroimaging studies are acquiring data to examine changes in brain architecture by investigating intrinsic functional networks (IFN) from longitudinal resting‐state functional MRI (rs‐fMRI). At the subject level, these IFNs are determined by cross‐sectional procedures, which neglect intra‐subject dependencies and result in suboptimal estimates of the networks. Here, a novel longitudinal approach simultaneously extracts subject‐specific IFNs across multiple visits by explicitly modeling functional brain development as an essential context for seeking change. On data generated by an innovative simulation based on real rs‐fMRI, the method was more accurate in estimating subject‐specific IFNs than cross‐sectional approaches. Furthermore, only group‐analysis based on longitudinally consistent estimates identified significant developmental effects within IFNs of 246 adolescents from the National Consortium on Alcohol and NeuroDevelopment in Adolescence (NCANDA) study. The findings were confirmed by the cross‐sectional estimates when the corresponding group analysis was confined to the developmental effects. Those effects also converged with current concepts of neurodevelopment.     

An appraisal of current dysphagia diagnosis and treatment strategies

Dysphagia is a common, serious health problem with a wide variety of etiologies and manifestations. This review gives a general overview of diagnostic and therapeutic options for oropharyngeal as well as esophageal swallowing disorders respecting the considerable progress made over recent years. Diagnosis can be challenging and requires expertise in interpretation of symptoms and patient history. Endoscopy, barium radiography and manometry are still the diagnostic mainstays. Classification of esophageal motor-disorders has been revolutionized with the introduction of high-resolution esophageal pressure topography and a new standardized classification algorithm. Automated integrated impedance manometry is a promising upcoming tool for objective evaluation of oropharyngeal dysphagia, in non-obstructive esophageal dysphagia and prediction of post fundoplication dysphagia risk. Impedance planimetry provides new diagnostic information on esophageal and LES-distensibility and allows controlled therapeutic dilatation without the need for radiation. Peroral endoscopic myotomy is a promising therapeutic approach for achalasia and spastic motility disorders.     

Contribution of alcoholism to brain dysmorphology in HIV infection: effects on the ventricles and corpus callosum

Nonrigid registration and atlas-based parcellation methods were used to compare the volume of the ventricular system and the cross-sectional area of the midsagittal corpus callosum on brain MRIs from 272 subjects in four groups: patients with HIV infection, with and without alcoholism comorbidity, alcoholics, and controls. Prior to testing group differences in regional brain metrics, each measure was corrected by regression analysis for significant correlations with supratentorial cranial volume and age, observed in 121 normal control men and women, whose age spanned six decades. Disregarding HIV disease severity, we observed a graded pattern of modest enlargement of the total ventricular system (0.28 SD for uncomplicated HIV, 0.65 SD for HIV comorbid with alcoholism, and 0.72 SD for the alcoholism group). The pattern of callosal thinning showed a similar but small ( approximately 0.5 SD) graded effect. A different pattern emerged, however, when HIV severity in the context of alcoholism comorbidity was factored into the analysis. Substantially greater volume abnormalities were present in individuals with a history of an AIDS-defining event or low CD4+ T cell counts (相似文献   

fMRI evidence for individual differences in premotor modulation of extrastriatal visual-perceptual processing of redundant targets

To perceive the vast array of stimuli in the world around us, the visual system employs parallel processing mechanisms that ensure efficiency in perceiving multiple objects in a scene. A way to test this efficiency is to measure reaction time (RT) to pairs of identical stimuli, presented singly or as doublets; typically, the resulting phenomenon is the redundant targets effect (RTE), which manifests as faster RTs to paired than singly presented stimuli. It is controversial, however, whether the neural locus of the parallel processing mechanisms invoked to produce the RTE is perceptual or motor and why some studies observe a substantial RTE and others do not. To resolve these two issues, we measured the RTE in young adults while undergoing functional MRI. Regarding the question of a perceptual or motor basis for the RTE, we observed that bilateral activation of extrastriate cortex was prominent in paired vs. the sum of the two single stimulus conditions, indicating that the RTE invoked perceptual mechanisms; by contrast, the motor cortex was not disproportionately activated in this comparison. Regarding the magnitude of the RTE, we compared activation patterns in individuals with small vs. large RTEs and observed that frontal and premotor areas were activated with small RTEs. These data indicate that the primary processing level of response facilitation, observed as the RTE, is perceptual, but the modulation of the RTE magnitude is premotor and associated with basic aspects of response selection and preparation.     

A Novel Method of Forceps Biopsy Improves the Diagnosis of Proximal Biliary Malignancies

Background and Aims  

Tissue specimen collection represents a cornerstone in diagnosis of proximal biliary tract malignancies offering great specificity, but only limited sensitivity. To improve the tumor detection rate, we developed a new method of forceps biopsy and compared it prospectively with endoscopic transpapillary brush cytology.     

Aktuelle Konzepte in der Diagnostik und Therapie des Diabetes mellitus

Die Radiologie - In Deutschland sind aktuell ca. 7,2 % der Bevölkerung an Diabetes mellitus erkrankt. Mit einer weiteren Zunahme der Prävalenz ist in den kommenden Jahren zu...     

Brain responses to emotional salience and reward in alcohol use disorder

Heightened neural responsiveness of alcoholics to alcohol cues and social emotion may impede sobriety. To test mesocorticolimbic network responsivity, 10 (8 men) alcohol use disorder (AUD) patients sober for 3 weeks to 10 months and 11 (8 men) controls underwent fMRI whilst viewing pictures of alcohol and non-alcohol beverages and of emotional faces (happy, sad, angry). AUD and controls showed similarities in mesocorticolimbic activity: both groups activated fusiform for emotional faces and hippocampal and pallidum regions during alcohol picture processing. In AUD, less fusiform activity to emotional faces and more pallidum activity to alcohol pictures were associated with longer sobriety. Using graph theory-based network efficiency measures to specify the role of the mesocorticolimbic network nodes for emotion and reward in sober AUD revealed that the left hippocampus was less efficiently connected with the other task-activated network regions in AUD than controls when viewing emotional faces, while the pallidum was more efficiently connected when viewing alcohol beverages. Together our findings identified lower occipito-temporal sensitivity to emotional faces and enhanced striatal sensitivity to alcohol stimuli in AUD than controls. Considering the role of the striatum in encoding reward, its activation enhancement with longer sobriety may reflect adaptive neural changes in the first year of drinking cessation and mesocorticolimbic system vulnerability for encoding emotional salience and reward potentially affecting executive control ability and relapse propensity during abstinence.     

Predominance of IncL/M and IncF plasmid types among CTX‐M‐ESBL‐producing Escherichia coli and Klebsiella pneumoniae in Bulgarian hospitals

Our objective was to investigate the plasmid replicon‐types involved in spread of ESBLs among Bulgarian Klebsiella pneumoniae and Escherichia coli. Sixty‐three isolates, with transferable beta‐lactam resistance determinants, collected between 2007 and 2009 in six medical institutions, were analysed with respect to their antimicrobial susceptibility, ESBL‐, RAPD‐, and plasmid replicon‐type. Phylogenetic typing and screening for the O25b‐ST131 lineage were carried out for E. coli. The predominant ESBLs were CTX‐M‐15 (81%) among E. coli and CTX‐M‐3 (58%) among K. pneumoniae. Other sporadically found ESBLs were SHV‐12 and TEM‐139, and for the first time in Bulgaria, CTX‐M‐1 and CTX‐M‐14. Replicon typing revealed that plasmids carrying bla_CTX‐M‐3 exclusively belonged to IncL/M‐type, while bla_CTX‐M‐15 was predominantly (94%) associated with IncF‐type plasmids. Among E. coli, 59% of the isolates were clonally related. Isolates of that cluster produced CTX‐M‐15, belonged to the O25b‐ST131 lineage, predominantly harboured plasmids with the FIA replicon, and were found in five centres. Among CTX‐M‐3‐producing K. pneumoniae, two prevailing RAPD‐types were found, one remained restricted to one centre and the second was found in three centres. The incompatibility groups IncN and IncA/C linked with bla_SHV‐12 respectively bla_TEM‐139 were found only once. To the best of our knowledge, this is the first detailed investigation of plasmids carrying ESBL genes among Bulgarian isolates demonstrating wide distribution of conjugative IncF plasmids among CTX‐M‐15‐producing E. coli and IncL/M plasmids among CTX‐M‐3 positive K. pneumoniae isolates.     

Pregnancy and adolescence entail similar neuroanatomical adaptations: A comparative analysis of cerebral morphometric changes

Mapping the impact of pregnancy on the human brain is essential for understanding the neurobiology of maternal caregiving. Recently, we found that pregnancy leads to a long‐lasting reduction in cerebral gray matter volume. However, the morphometric features behind the volumetric reductions remain unexplored. Furthermore, the similarity between these reductions and those occurring during adolescence, another hormonally similar transitional period of life, still needs to be investigated. Here, we used surface‐based methods to analyze the longitudinal magnetic resonance imaging data of a group of 25 first‐time mothers (before and after pregnancy) and compare them to those of a group of 25 female adolescents (during 2 years of pubertal development). For both first‐time mothers and adolescent girls, a monthly rate of volumetric reductions of 0.09 mm³ was observed. In both cases, these reductions were accompanied by decreases in cortical thickness, surface area, local gyrification index, sulcal depth, and sulcal length, as well as increases in sulcal width. In fact, the changes associated with pregnancy did not differ from those that characterize the transition during adolescence in any of these measures. Our findings are consistent with the notion that the brain morphometric changes associated with pregnancy and adolescence reflect similar hormonally primed biological processes.