Detailed anatomic segmentations of a fetal brain diffusion tensor imaging atlas between 23 and 30 weeks of gestation

This work presents detailed anatomic labels for a spatiotemporal atlas of fetal brain Diffusion Tensor Imaging (DTI) between 23 and 30 weeks of post‐conceptional age. Additionally, we examined developmental trajectories in fractional anisotropy (FA) and mean diffusivity (MD) across gestational ages (GA). We performed manual segmentations on a fetal brain DTI atlas. We labeled 14 regions of interest (ROIs): cortical plate (CP), subplate (SP), Intermediate zone‐subventricular zone‐ventricular zone (IZ/SVZ/VZ), Ganglionic Eminence (GE), anterior and posterior limbs of the internal capsule (ALIC, PLIC), genu (GCC), body (BCC), and splenium (SCC) of the corpus callosum (CC), hippocampus, lentiform Nucleus, thalamus, brainstem, and cerebellum. A series of linear regressions were used to assess GA as a predictor of FA and MD for each ROI. The combination of MD and FA allowed the identification of all ROIs. Increasing GA was significantly associated with decreasing FA in the CP, SP, IZ/SVZ/IZ, GE, ALIC, hippocampus, and BCC (p < .03, for all), and with increasing FA in the PLIC and SCC (p < .002, for both). Increasing GA was significantly associated with increasing MD in the CP, SP, IZ/SVZ/IZ, GE, ALIC, and CC (p < .03, for all). We developed a set of expert‐annotated labels for a DTI spatiotemporal atlas of the fetal brain and presented a pilot analysis of developmental changes in cerebral microstructure between 23 and 30 weeks of GA.     

In Envelope Additive/Subtractive Manufacturing and Thermal Post-Processing of Inconel 718

This study investigated the application of an in envelope additive/subtractive (LPBF) manufacturing method (Matsuura LUMEX-Avance-25) to fabricate IN718 benchmarking coupons. The coupons were then examined comprehensively for surface finish both with and without high-speed micro-machining. The microstructure of the manufactured IN718 coupons was investigated thoroughly in the as-fabricated condition and following three different standard and one non-standard post-processing heat treatments. As built coupons revealed columnar grain morphology mainly along the <100> direction with a cellular dendritic sub-grain structure and without any strengthening precipitates. Grain size, aspect ratio, and texture were maintained after each of the applied four heat treatments. Only one of the standard heat treatments resulted in the δ phase formation. The other three heat treatments effectively dissolved the Laves phase preventing the δ formation while promoting the formation of γ′/γ″ precipitates. Despite the observed differences in their microstructures, all of the heat treatments resulted in similar yield and ultimate tensile strength values that ranged between 1103–1205 MPa and 1347–1387 MPa, respectively. These values are above the minimum requirements of 1034 MPa and 1241 MPa for the wrought material. The non-standard heat treatment provided the highest elongation of 24.0 ± 0.1% amongst all the heat-treated specimens without a significant loss in strength, while the standard heat treatment for the wrought parts resulted in the lowest elongation of 18.3 ± 0.7% due to the presence of δ phase.     

Role of nitric oxide in the anticonvulsive effect of progesterone

Described here is an investigation of the potential interaction of the nitric oxide signaling pathway with the anticonvulsant effects of progesterone. In ovariectomized Swiss mice, the threshold for seizures induced by intravenous infusion of pentylenetetrazole was determined after treatment with progesterone (25, 50, or 75 mg/kg, given subcutaneously 6h before seizure testing) or vehicle. Progesterone induced significant anticonvulsive activity at moderate (50 mg/kg) and high (75 mg/kg) doses. This effect of progesterone was abolished by the NO precursor compound L-arginine (200 mg/kg). Moreover, when subeffective doses of progesterone (25 mg/kg) and the NO synthase inhibitor N(omega)-nitro-L-arginine methyl ester (10 mg/kg) were injected, a strong anticonvulsant effect was observed. These findings suggest a potential role for NO signaling as an anticonvulsant target in females.     

Functional connectivity in patients with idiopathic generalized epilepsy

Purpose: Idiopathic generalized epilepsy (IGE) is characterized by electroencephalography (EEG) recordings with generalized spike wave discharges (GSWDs) arising from normal background activity. Although GSWDs are the result of highly synchronized activity in the thalamocortical network, EEG without GSWDs is believed to represent normal brain activity. The aim of this study was to investigate whether thalamocortical interactions are altered even during GSWD‐free EEG periods in patients with IGE. Methods: A GSWD‐related group analysis was performed in 12 IGE patients to define seeds in areas involved during GSWDs. EEG–functional magnetic resonance imaging (fMRI) datasets from 22 IGE patients without GSWDs during the investigation and 30 age‐matched healthy controls were then selected to investigate functional connectivity in GSWD‐related areas. Blood oxygen level dependent (BOLD) signal changes were extracted from seeds defined by the GSWD‐related group analysis. The averaged time course within each seed was used to detect brain regions with BOLD signal correlated with the seed. Group differences between patients and controls were estimated. Key Findings: The GSWD‐related group analysis showed BOLD activation in the thalamus, the frontomesial cortex, and the cerebellum and BOLD deactivation in default mode areas. For the connectivity analysis, eight seeds were placed bilaterally in the thalamus, mesial frontal cortex, precuneus, and cerebellum. The functional connectivity analysis of these seeds did not show clearly altered functional connectivity for patients versus controls. Significance: The results underscore the paroxysmal nature of GSWDs: Although GSWDs are characterized by highly synchronized activity in the thalamocortical network, the functional connectivity in areas involved during GSWDs does not demonstrate abnormality in GSWD‐free periods.     

Bilateral Hippocampal Restricted Diffusion: Same Picture Many Causes

With some regularity, we have encountered the unusual imaging abnormality of bilateral hippocampal restricted diffusion, either in isolation or in combination with other coincident abnormalities. In this retrospective case series, we examine clinical and imaging data to explore potential etiologies and clinical implications of this imaging finding. Sixteen cases with the imaging abnormality are presented, with etiologies including hypoxemia, hypoxemia‐ischemia, and seizures.     

A direct amygdala‐motor pathway for emotional displays to influence action: A diffusion tensor imaging study

An important evolutionary function of emotions is to prime individuals for action. Although functional neuroimaging has provided evidence for such a relationship, little is known about the anatomical substrates allowing the limbic system to influence cortical motor‐related areas. Using diffusion‐weighted magnetic resonance imaging and probabilistic tractography on a cohort of 40 participants, we provide evidence of a structural connection between the amygdala and motor‐related areas (lateral and medial precentral, motor cingulate and primary motor cortices, and postcentral gyrus) in humans. We then compare this connection with the connections of the amygdala with emotion‐related brain areas (superior temporal sulcus, fusiform gyrus, orbitofrontal cortex, and lateral inferior frontal gyrus) and determine which amygdala nuclei are at the origin of these projections. Beyond the well‐known subcortical influences over automatic and stereotypical emotional behaviors, a direct amygdala‐motor pathway might provide a mechanism by which the amygdala can influence more complex motor behaviors. Hum Brain Mapp 35:5974–5983, 2014. © 2014 Wiley Periodicals, Inc.     

Tracking Toxoplasma gondii in freshwater ecosystems: interaction with the invasive American mink (Neovison vison) in Spain

Parasitology Research - Water-borne transmission may play an important role in the epidemiology of Toxoplasma gondii. Mammals closely related to freshwater ecosystems, such as the American mink...     

A histopathological study of esophageal cancer on the western side of the Caspian littoral from 1994 to 2003

SUMMARY. Esophageal cancer (EC) accounts for a considerable proportion of carcinomas of the upper gastrointestinal tract in the population of the Caspian littoral. The global histologic pattern of the disease has changed recently. The intent of this study was to determine the incidence of EC over the past decade in Eastern Azerbaijan – a north‐western province of Iran – on the western side of the Caspian littoral and to assess the alteration of the histological pattern of the disease. In a retrospective study, all 1792 documented EC cases of all registered cancer, surgery, pathology, and radiotherapy centers of the province over a period of 9 years (from March 1994 to March 2003) were enrolled in the study. Data concerning demographic characteristics, EC risk factors, and histological findings were recorded. The incidence and the relative incidence of the pathological subtypes of EC in the population of the province were determined. The change in incidence rates and the interaction between main risk factors and tumor histology of the patients were assessed over the study years. The average incidence of EC in the over 30‐year‐old population of the province was 16.2 (12.7 for squamous cell carcinoma [SCC] and 1.9 for adenocarcinoma [AC]) cases per 100 000 person‐years. Incidence of SCC, as well as AC, peaked at ages older than 65. Compared to women, men had higher incidences of AC and lower incidences of SCC; the average incidence rate of EC was equal in men and women. AC and SCC accounted for 12.8% and 86.9% of cases, respectively. Upper, middle and lower thirds of the esophagus were the location of tumors in 9.8%, 32.9% and 57.3% of cases, respectively. During the study period, incidence rates of EC and SCC tended to decrease. The incidence rate of EC from 1995 to 1998 was almost 30% higher than that of the period from 1999 to 2002. Incidence rate of EC on the western side of the Caspian littoral is moderately high, but much lower than that of the eastern Caspian littoral as it was three decades ago. The incidence of EC was lower in the second half than the first half of the study period. Unlike the global pattern of EC, the incidence of EC as well as SCC in women is as high as or higher than in men, which is identical to the pattern in the eastern Caspian littoral.