98 research outputs found
Activations in temporal areas using visual and auditory naming stimuli: A language fMRI study in temporal lobe epilepsy
OBJECTIVE: Verbal fluency functional MRI (fMRI) is used for predicting language deficits after anterior temporal lobe resection (ATLR) for temporal lobe epilepsy (TLE), but primarily engages frontal lobe areas. In this observational study we investigated fMRI paradigms using visual and auditory stimuli, which predominately involve language areas resected during ATLR.
METHODS: Twenty-three controls and 33 patients (20 left (LTLE), 13 right (RTLE)) were assessed using three fMRI paradigms: verbal fluency, auditory naming with a contrast of auditory reversed speech; picture naming with a contrast of scrambled pictures and blurred faces.
RESULTS: Group analysis showed bilateral temporal activations for auditory naming and picture naming. Correcting for auditory and visual input (by subtracting activations resulting from auditory reversed speech and blurred pictures/scrambled faces respectively) resulted in left-lateralised activations for patients and controls, which was more pronounced for LTLE compared to RTLE patients.
Individual subject activations at a threshold of T > 2.5, extentâ>10 voxels, showed that verbal fluency activated predominantly the left inferior frontal gyrus (IFG) in 90% of LTLE, 92% of RTLE, and 65% of controls, compared to right IFG activations in only 15% of LTLE and RTLE and 26% of controls.
Middle temporal (MTG) or superior temporal gyrus (STG) activations were seen on the left in 30% of LTLE, 23% of RTLE, and 52% of controls, and on the right in 15% of LTLE, 15% of RTLE, and 35% of controls.
Auditory naming activated temporal areas more frequently than did verbal fluency (LTLE: 93%/73%; RTLE: 92%/58%; controls: 82%/70% (left/right)). Controlling for auditory input resulted in predominantly left-sided temporal activations.
Picture naming resulted in temporal lobe activations less frequently than did auditory naming (LTLE 65%/55%; RTLE 53%/46%; controls 52%/35% (left/right)). Controlling for visual input had left-lateralising effects.
CONCLUSION: Auditory and picture naming activated temporal lobe structures, which are resected during ATLR, more frequently than did verbal fluency. Controlling for auditory and visual input resulted in more left-lateralised activations. We hypothesise that these paradigms may be more predictive of postoperative language decline than verbal fluency fMRI
Decoupling of functional and structural language networks in temporal lobe epilepsy
OBJECTIVE: To identify functional and structural alterations in language networks of people with temporal lobe epilepsy (TLE), who frequently present with naming and word-finding difficulties. METHODS: Fifty-five patients with unilateral TLE (29Â left) and 16 controls were studied with auditory and picture naming functional magnetic resonance imaging (fMRI) tasks. Activation maxima in the left posterobasal temporal lobe were used as seed regions for whole-brain functional connectivity analyses (psychophysiological interaction). White matter language pathways were investigated using diffusion tensor imaging and neurite orientation dispersion and density imaging metrics extracted along fiber bundles starting from fMRI-guided seeds. Regression analyses were performed to investigate the correlation of functional connectivity with diffusion MRI metrics. RESULTS: In the whole group of patients and controls, weaker functional connectivity from the left posterobasal temporal lobe (1) to the bilateral anterior temporal lobe, precentral gyrus, and lingual gyrus during auditory naming and (2) to the bilateral occipital cortex and right fusiform gyrus during picture naming was associated with decreased neurite orientation dispersion and higher free water fraction of white matter tracts. Compared to controls, TLE patients exhibited fewer structural connections and an impaired coupling of functional and structural metrics. SIGNIFICANCE: TLE is associated with an impairment and decoupling of functional and structural language networks. White matter damage, as evidenced by diffusion abnormalities, may contribute to impaired functional connectivity and language dysfunction in TLE
ICN_Atlas: Automated description and quantification of functional MRI activation patterns in the framework of intrinsic connectivity networks.
Generally, the interpretation of functional MRI (fMRI) activation maps continues to rely on assessing their relationship to anatomical structures, mostly in a qualitative and often subjective way. Recently, the existence of persistent and stable brain networks of functional nature has been revealed; in particular these so-called intrinsic connectivity networks (ICNs) appear to link patterns of resting state and task-related state connectivity. These networks provide an opportunity of functionally-derived description and interpretation of fMRI maps, that may be especially important in cases where the maps are predominantly task-unrelated, such as studies of spontaneous brain activity e.g. in the case of seizure-related fMRI maps in epilepsy patients or sleep states. Here we present a new toolbox (ICN_Atlas) aimed at facilitating the interpretation of fMRI data in the context of ICN. More specifically, the new methodology was designed to describe fMRI maps in function-oriented, objective and quantitative way using a set of 15 metrics conceived to quantify the degree of 'engagement' of ICNs for any given fMRI-derived statistical map of interest. We demonstrate that the proposed framework provides a highly reliable quantification of fMRI activation maps using a publicly available longitudinal (test-retest) resting-state fMRI dataset. The utility of the ICN_Atlas is also illustrated on a parametric task-modulation fMRI dataset, and on a dataset of a patient who had repeated seizures during resting-state fMRI, confirmed on simultaneously recorded EEG. The proposed ICN_Atlas toolbox is freely available for download at http://icnatlas.com and at http://www.nitrc.org for researchers to use in their fMRI investigations
Naming fMRI predicts the effect of temporal lobe resection on language decline
Objective:
To develop language functional MRI (fMRI) methods that accurately predict postsurgical naming decline in temporal lobe epilepsy (TLE).
Methods:
Fortyâsix patients with TLE (25 left) and 19 controls underwent two overt fMRI paradigms (auditory naming and picture naming, both with active baseline conditions) and one covert task (verbal fluency). Clinical naming performance was assessed preoperatively and 4 months following anterior temporal lobe resection. Preoperative fMRI activations were correlated with postoperative naming decline. Individual laterality indices (LI) were calculated for temporal (auditory and picture naming) and frontal regions (verbal fluency) and were considered as predictors of naming decline in multiple regression models, along with other clinical variables (age at onset of seizures, preoperative naming scores, hippocampal volume, age).
Results:
In left TLE patients, activation of the left posterior inferior temporal gyrus during auditory naming and activation of left fusiform gyrus during picture naming were related to greater postoperative naming decline. Activation LI were the best individual predictors of naming decline in a multivariate regression model. For picture naming, an LI of higher than 0.34 gave 100% sensitivity and 92% specificity (positive predictive value (PPV) 91.6%). For auditory naming, a temporal lobe LI higher than 0.18 identified all patients with a clinically significant naming decline with 100% sensitivity and 58% specificity (PPV: 58.3%). No effect was seen for verbal fluency.
Interpretation:
Auditory and picture naming fMRI are clinically applicable to predict postoperative naming decline after left temporal lobe resection in individual patients, with picture naming being more specific
Facing the stranger in the mirror: Staged complicities in recent South African performances
The staging of complicity has developed into one of the most prevalent trends in
recent South Africa theatre. The audience may become aware of their own
complicity in injustice, or complicity may feature as a subject to be explored in the
play. I will argue that one can identify three broadly defined performance
modalities which shape current engagements with complicity. These modalities
are identified by the adjectives, 'thick' (as in densely layered, complex, deep),
'reflective' (as in reflecting upon as well as revealing), and 'hard' (in the sense of
direct, uncompromising, difficult to penetrate). Rather than signifying distinct
categories, these terms are attributed to a cluster of performance dynamics.DHE
Influence of pharmacogenetic variability on the pharmacokinetics and toxicity of the aurora kinase inhibitor danusertib
Objectives Danusertib is a serine/threonine kinase inhibitor of multiple kinases, including aurora-A, B, and C. This explorative study aims to identify possible relationships between single nucleotide polymorphisms in genes coding for drug metabolizing enzymes and transporter proteins and clearance of danusertib, to clarify the interpatient variability in exposure. In addition, this study explores the relationship between target receptor polymorphisms and toxicity of danusertib. Methods For associations with clearance, 48 cancer patients treated in a phase I study were analyzed for ABCB1, ABCG2 and FMO3 polymorphisms. Association analyses between neutropenia and drug target receptors, including KDR, RET, FLT3, FLT4, AURKB and AURKA, were performed in 30 patients treated at recommended phase II dose-levels in three danusertib phase I or phase II trials. Results No relationships between danusertib clearance and drug metabolizing enzymes and transporter protein polymorphisms were found. Only, for the one patient with FMO3 18281AA polymorphism, a significantly higher clearance was noticed, compared to patients carrying at least 1 wild type allele. No effect of target receptor genotypes or haplotypes on neutropenia was observed. Conclusions As we did not find any major correlations between pharmacogenetic variability in the studied enzymes and transporters and pharmacokinetics nor toxicity, it is unlikely that danusertib is highly susceptible for pharmacogenetic variation. Therefore, no dosing alterations of danusertib are expected in the future, based on the polymorphisms studied. However, the relationship between FMO3 polymorphisms and clearance of danusertib warrants further research, as we could study only a small group of patients
Influence of vitamin D supplementation on bone mineral content, bone turnover markers and fracture risk in South African schoolchildren: Multicentre double-blind randomised placebo-controlled trial (ViDiKids)
Randomised controlled trials (RCT) to determine the influence of vitamin D on bone mineral content (BMC) and fracture risk in children of Black African ancestry are lacking. We conducted a sub-study (n=450) nested within a Phase 3 RCT of weekly oral supplementation with 10,000 IU vitamin D3 vs. placebo for 3 years in HIV- uninfected Cape Town schoolchildren aged 6-11 years. Outcomes were BMC at the whole body less head (WBLH) and lumbar spine (LS) and serum 25-hydroxyvitamin D3 (25[OH]D3), parathyroid hormone (PTH), alkaline phosphatase, C-terminal telopeptide and procollagen type 1 N propeptide. Incidence of fractures was a secondary outcome of the main trial (n=1682). At baseline, mean serum 25(OH)D3 concentration was 70.0 nmol/L (s.d. 13.5), and 5.8% of participants had serum 25(OH)D3 concentrations <50 nmol/L. Among sub-study participants, end-trial serum 25(OH)D3 concentrations were higher for participants allocated to vitamin D vs. placebo (adjusted mean difference [aMD] 39.9 nmol/L, 95% CI 36.1 to 43.6) and serum PTH concentrations were lower (aMD -0.55 pmol/L, 95% CI -0.94 to -0.17). However, no interarm differences were seen for WBLH BMC (aMD -8.0 g, 95% CI - 30.7 to 14.7) or LS BMC (aMD -0.3 g, 95% CI -1.3 to 0.8) or serum concentrations of bone turnover markers. Fractures were rare among participants in the main trial randomised to vitamin D vs. placebo (7/755 vs. 10/758 attending at least one follow- up; adjusted odds ratio 0.70, 95% CI 0.27 to 1.85). In conclusion, a 3-year course of weekly oral vitamin D supplementation elevated serum 25(OH)D3 concentrations and suppressed serum PTH concentrations in HIV-uninfected South African schoolchildren of Black African ancestry but did not influence BMC or serum concentrations of bone turnover markers. Fracture incidence was low, limiting power to detect an effect of vitamin D on this outcome
âDrink lots of clean, safe waterâ: A food-based dietary guideline for South Africa
The purpose of this review is to summarise the literature that supports the importance of the food-based dietary guideline on water consumption. General recommendations for total daily water intake are between 2 and 3.7 l for women and men, 0.7 l for infants aged 0-6 months, 0.8 l for infants aged 7-12 months, 1.3 l for children aged 1-3 years, and 1.7 l for children aged 4-8 years. Water recommendations for the elderly and people who are involved in exercise or hard physical labour may be higher and might need special consideration. Water remains one of the primary sources of fluoride, and in areas with low levels, the fluoridation of drinking water is recommended. Defluoridation of water is suggested in areas where water fluoride levels exceed 3 mg/l. There is a paucity of South African data on general fluid intake, but some evidence suggests an increase in the intake of energy-containing beverages and in the demand for bottled water, posing unique challenges relating to weight gain and diabetes incidence, and effects on the environment and chemical leaching, respectively. Water quality remains a concern. Low rainfall, declining fresh water sources and the impact of industrial activity, urbanisation, climate change, deforestation, mining and agriculture add pressure on water bodies. This effect on water quality could lead to water-borne illnesses and disease. Managing the quality of drinking water is of utmost importance, and pertains to the microbiological and chemical safety of water, as well as to the physical and organoleptic qualities of drinking water, which is an important cornerstone for health
Drink lots of clean, safe water:Â Â a foodâbased dietary guideline for South Africa
The purpose of this review is to summarise the literature that supports the importance of the food-based dietary guideline
on water consumption. General recommendations for total daily water intake are between 2 and 3.7 l for women
and men, 0.7 l for infants aged 0-6 months, 0.8 l for infants aged 7-12 months, 1.3 l for children aged 1-3 years, and
1.7 l for children aged 4-8 years. Water recommendations for the elderly and people who are involved in exercise or
hard physical labour may be higher and might need special consideration. Water remains one of the primary sources
of fluoride, and in areas with low levels, the fluoridation of drinking water is recommended. Defluoridation of water is
suggested in areas where water fluoride levels exceed 3 mg/l. There is a paucity of South African data on general fluid
intake, but some evidence suggests an increase in the intake of energy-containing beverages and in the demand for
bottled water, posing unique challenges relating to weight gain and diabetes incidence, and effects on the environment
and chemical leaching, respectively. Water quality remains a concern. Low rainfall, declining fresh water sources and
the impact of industrial activity, urbanisation, climate change, deforestation, mining and agriculture add pressure on
water bodies. This effect on water quality could lead to water-borne illnesses and disease. Managing the quality of
drinking water is of utmost importance, and pertains to the microbiological and chemical safety of water, as well as to
the physical and organoleptic qualities of drinking water, which is an important cornerstone for healt
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