The Experts below are selected from a list of 5685 Experts worldwide ranked by ideXlab platform
Neil Roberts - One of the best experts on this subject based on the ideXlab platform.
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voxel based morphometry and Stereology provide convergent evidence of the importance of medial prefrontal cortex for fluid intelligence in healthy adults
NeuroImage, 2005Co-Authors: Qiyong Gong, Vanessa Sluming, Andrew R Mayes, Simo S Kelle, T R Arrick, Enis Cezayirli, Neil RobertsAbstract:Abstract We investigated whether a relationship exists between frontal lobe volume and fluid intelligence as measured by both Cattell's Culture Fair test and the Wechsler Adult Intelligence Scale-Revised (WAIS-R) Performance scale, but not with crystallized intelligence as measured by the WAIS-R Verbal scale, in healthy adults, using two well-established image analysis techniques applied to high-resolution MR brain images. Firstly, using voxel-based morphometry (VBM), we investigated whether a significant relationship exists between gray matter concentration and fluid intelligence on a voxel-by-voxel basis. Secondly, we applied the Cavalieri method of modern design Stereology in combination with point counting to investigate possible relationships between macroscopic volumes of relevant brain regions defined as dorsolateral, dorsomedial, orbitolateral, and orbitomedial prefrontal cortex on the basis of neuroanatomical landmarks, and fluid intelligence. We also examined the effect on these relationships of normalizing regional brain volumes to intracranial volume. VBM analysis revealed a positive correlation between gray matter concentration in the medial region of prefrontal cortex and Culture Fair scores (corrected for multiple comparisons), and also WAIS-R Performance Intelligence sum of scaled scores (SSS) (uncorrected for multiple comparisons before controlling for age, and this converges with the stereological finding of the positive correlation between volume of dorsomedial prefrontal cortex normalized to intracranial volume and Culture Fair scores after controlling for age. WAIS-R Verbal Intelligence SSS showed no correlations. We interpret our findings, from independent analyses of both VBM and Stereology, as evidence of the importance of medial prefrontal cortex in supporting fluid intelligence.
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voxel based morphometry of grey matter abnormalities in patients with medically intractable temporal lobe epilepsy effects of side of seizure onset and epilepsy duration
Journal of Neurology Neurosurgery and Psychiatry, 2002Co-Authors: Simon S. Keller, U C Wieshmann, Clare E Mackay, Christine Denby, J A Webb, Neil RobertsAbstract:Objectives: To investigate the use of whole brain voxel based morphometry (VBM) and stereological analysis to study brain morphology in patients with medically intractable temporal lobe epilepsy; and to determine the relation between side, duration, and age of onset of temporal lobe epilepsy, history of childhood febrile convulsions, and grey matter structure. Methods: Three dimensional magnetic resonance images were obtained from 58 patients with left sided seizure onset (LSSO) and 58 patients with right sided seizure onset (RSSO), defined using EEG and foramen ovale recordings in the course of presurgical evaluation for temporal lobectomy. Fifty eight normal controls formed a comparison group. VBM was used to characterise whole brain grey matter concentration, while the Cavalieri method of modern design Stereology in conjunction with point counting was used to estimate hippocampal and amygdala volume. Age and sex were used as confounding covariates in analyses. Results: LSSO and RSSO patients showed significant reductions in volume (using Stereology) and grey matter concentration (using VBM) of the hippocampus, but not of the amygdala, in the presumed epileptogenic zone when compared with controls, but hippocampal (and amygdala) volume and grey matter concentration were not related to duration or age of onset of epilepsy. LSSO and RSSO patients with a history of childhood febrile convulsions had reduced hippocampal volumes in the presumed epileptogenic zone compared with patients without such a history. Left amygdala volume was also reduced in LSSO patients with a history of childhood convulsions. VBM results indicated bilateral thalamic, prefrontal, and cerebellar GMC reduction in patients, which correlated with duration and age of onset of epilepsy. Conclusions: Hippocampal sclerosis is not necessarily the consequence of recurrent temporal lobe seizures. A major cause of hippocampal sclerosis appears to be an early aberrant neurological insult, such as childhood febrile seizures. Secondary brain abnormalities exist in regions outside the presumed epileptogenic zone and may result from recurrent seizures.
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fetal and fetal organ volume estimations with magnetic resonance imaging
American Journal of Obstetrics and Gynecology, 1996Co-Authors: Anne Garden, Neil RobertsAbstract:Abstract OBJECTIVE: Our purpose was to estimate, with the Cavalieri method of Stereology and a point-counting technique, the volume of the fetus, fetal brain, fetal liver, and fetal lungs. STUDY DESIGN: Four pregnancies were studied on three to five occasions at gestations from 27 weeks until term. RESULTS: In the four fetuses studied the total fetal volume increased at a rate of between 19.0 and 30.8 ml/day. The fetal liver constituted 2.5% to 4.9% of the total fetal volume; the fetal lung, 2.5% to 4.4%; and the fetal brain, 11.5% to 16.9%. The fetal liver increased in size by 0.4 to 1.3 ml/day; the lungs, by 1.2 to 1.4 ml/day; and the fetal brain, by 2.7 to 3.8 ml/day. The fetal brain/liver ratio, which may be an indicator of an asymmetric growth pattern, was between 2.4 and 5.6 with a tendency to a decreased ratio with increasing gestation. CONCLUSION: This is the first serial study of total fetal volume and fetal organ volume with magnetic resonance imaging and Stereology. Measurement of the total fetal volume and differential growth of fetal organs may be a more sensitive method of assessing fetal intrauterine growth than two-dimensional measurements obtained with ultrasonography. (Am J Obstet Gynecol 1996;175:442-8.)
Issam I Raad - One of the best experts on this subject based on the ideXlab platform.
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a design based stereologic method to quantify the tissue changes associated with a novel drug eluting tracheobronchial stent
Respiration, 2019Co-Authors: Labib Debiane, Horiana B. Grosu, Joel Rosenblatt, Mihai Gagea, Miguel A Chavez, Roberto Adachi, Ajay Sheshadri, Lori R Hill, Ruth Reitzel, Issam I RaadAbstract:BACKGROUND: Granulation tissue is a common complication of airway stenting, but no published methods can quantify the volume and type of tissue that develops. OBJECTIVE: To use design-based Stereology to quantify changes in tissue volume and type associated with airway stenting. METHODS: We compared drug-eluting stents (DES) filled with gendine to standard silicone stents in pigs in an assessor-blinded randomized trial. Tracheal stents were placed via rigid bronchoscopy. After 1 month, animals were euthanized and necropsies were performed. Antimicrobial effects of the DES were assessed in trachea tissue samples, on the DES surface, and with residual gel from the DES reservoir. Tracheal thickness was measured using orthogonal intercepts. Design-based Stereology was used to quantify the volume density of tissues using a point-counting method. The volume of each tissue was normalized to cartilage volume, which is unaffected by stenting. RESULTS: Pigs were randomized to DES (n = 36) or control stents (n = 9). The drug was successfully eluted from the DES, and the stent surface showed antibacterial activity. DES and controls did not differ in tissue microbiology, tracheal thickness, or granulation tissue volume. Compared to nonstented controls, stented airways demonstrated a 110% increase in soft-tissue volume (p = 0.005). Submucosal connective tissue (118%; p < 0.0001), epithelium (70%; p < 0.0001), submucosal glands (47%; p = 0.001), and smooth muscle (41%; p < 0.0001) increased in volume. CONCLUSION: Stenting doubles the volume of soft tissue in the trachea. Design-based Stereology can quantify the tissue changes associated with airway stenting.
Oyekoya T Ayonrinde - One of the best experts on this subject based on the ideXlab platform.
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stereological analysis of liver biopsy histology sections as a reference standard for validating non invasive liver fat fraction measurements by mri
PLOS ONE, 2016Co-Authors: Timothy G St Pierre, Michael J House, Sander J Bangma, Wenjie Pang, Andrew Bathgate, Eng K Gan, Oyekoya T AyonrindeAbstract:Background and Aims Validation of non-invasive methods of liver fat quantification requires a reference standard. However, using standard histopathology assessment of liver biopsies is problematical because of poor repeatability. We aimed to assess a stereological method of measuring volumetric liver fat fraction (VLFF) in liver biopsies and to use the method to validate a magnetic resonance imaging method for measurement of VLFF. Methods VLFFs were measured in 59 subjects (1) by three independent analysts using a stereological point counting technique combined with the Delesse principle on liver biopsy histological sections and (2) by three independent analysts using the HepaFat-Scan® technique on magnetic resonance images of the liver. Bland Altman statistics and intraclass correlation (IC) were used to assess the repeatability of each method and the bias between the methods of liver fat fraction measurement. Results Inter-analyst repeatability coefficients for the Stereology and HepaFat-Scan® methods were 8.2 (95% CI 7.7–8.8)% and 2.4 (95% CI 2.2–2.5)% VLFF respectively. IC coefficients were 0.86 (95% CI 0.69–0.93) and 0.990 (95% CI 0.985–0.994) respectively. Small biases (≤3.4%) were observable between two pairs of analysts using Stereology while no significant biases were observable between any of the three pairs of analysts using HepaFat-Scan®. A bias of 1.4±0.5% VLFF was observed between the HepaFat-Scan® method and the stereological method. Conclusions Repeatability of the stereological method is superior to the previously reported performance of assessment of hepatic steatosis by histopathologists and is a suitable reference standard for validating non-invasive methods of measurement of VLFF.
Nobuhide Kasagi - One of the best experts on this subject based on the ideXlab platform.
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1 Microstructure and Polarization Characteristics of Anode Supported Tubular SOFC with Co-precipitated and Mechanically Mixed Ni-YSZ Anodes
2015Co-Authors: Naoki Shikazono, Yusuke Sakamoto, Yu Yamaguchi, Nobuhide KasagiAbstract:An anode support tubular SOFC is fabricated and the dependence of its polarization resistance on anode microstructural parameters is investigated by means of Stereology and concept of contiguity (c-c) theory. Nickel yttria-stabilized zirconia (Ni-YSZ) anode supported cell with YSZ electrolyte, lanthanum-strontium-manganite (LSM)-YSZ composite cathode, and LSM cathode layers is fabricated by dip coating. Submicrometer resolution images of anode microstructure are successfully obtained by low voltage SEM-EDX and quantified by stereological analysis. Cell voltage measurements and impedance spectroscopy are performed at temperatures of 650 and 750˚C with hydrogen and nitrogen mixture gas as a fuel. A quantitative relationship between polarization resistance and microstructural parameters such as circularity, three-phase boundary length and contiguity etc. is investigated using the concept of contiguity (c-c) theory. The effectiveness of correlating polarization resistance of anode supported tubular SOFC using Stereology and c-c theory is evaluated
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microstructure and polarization characteristics of anode supported tubular solid oxide fuel cell with co precipitated and mechanically mixed ni ysz anodes
Journal of Power Sources, 2009Co-Authors: Naoki Shikazono, Yusuke Sakamoto, Yu Yamaguchi, Nobuhide KasagiAbstract:Abstract An anode support tubular solid oxide fuel cell (SOFC) is fabricated and the dependence of its polarization resistance on anode microstructural parameters is investigated by means of Stereology and concept of contiguity (c-c) theory. Nickel yttria-stabilized zirconia (Ni-YSZ) anode supported cell with YSZ electrolyte, lanthanum–strontium–manganite (LSM)-YSZ composite cathode, and LSM cathode layers is fabricated by dip coating. Submicrometer resolution images of anode microstructure are successfully obtained by low voltage SEM-EDX and quantified by stereological analysis. Cell voltage measurements and impedance spectroscopy are performed at temperatures of 650 and 750 °C with hydrogen and nitrogen mixture gas as a fuel. A quantitative relationship between polarization resistance and microstructural parameters such as circularity, three-phase boundary length, contiguity, etc. is investigated using the concept of contiguity (c-c) theory. The effectiveness of correlating polarization resistance of anode supported tubular SOFC using Stereology and c-c theory is evaluated.
Flemming Brandt Sorensen - One of the best experts on this subject based on the ideXlab platform.
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does heterogeneity matter in the estimation of tumour budding and tumour stroma ratio in colon cancer
Diagnostic Pathology, 2018Co-Authors: Ann C. Eriksen, Jan Lindebjerg, René Depont Christensen, Torben Hansen, Johnnie B. Andersen, Sanne Kjaerfrifeldt, Flemming Brandt SorensenAbstract:Tumour budding (TB) and Tumour Stroma Ratio (TSR) may be rewarding in the treatment stratification of patients with stage II colon cancer. However, lack of standardization may exclude these parameters from being used in a clinical setting. The purpose of this methodologic study was to compare Stereology with semi-quantitative estimations of TSR, to investigate the intra-tumoural heterogeneity of TB and TSR, and to assess the intra- and inter-observer agreement. Three paraffin embedded tumour blocks, one of them representing the deepest invasive front, were selected from each of 43 patients treated for stage II colon cancer. TSR was estimated in HE however due to low representation of high-budding tumours, results must be considered with caution.
