1,175 research outputs found
From patriliny to matriliny : structural change among the Redjang of southwest Sumatra
This thesis attempts to describe in its cultural
setting the social structure of the Redjang people of
Southwest Sumatra in the way that I observed and experienced
it in the course of twenty months field work from
May to October 1961 and from March 1962 to April 1963. The
rich variety of Redjang social life can only partly be described
with the written word. The structural forms of the
remote past, the near past and the infinite gradations of the present, need more than written words to describe them«,
Patterns of domestic organisation, for example, require
graphic illustration to explain past and present arrangements
adequately. Similarly the change of ideology from
patriliny to matriliny is not merely a change in a
sociological norm or an institutional adjustment but represents
a major social and cultural shift that is expressed
and reflected in myths, legends, anecdotes, ceremonial
songs, lamentations, dances, gestures, rituals,
sociodramas, apparel, ornamentation, cuisine, domestic
architecture, household composition, kinship relations and
terminology, village structure, the rules of marriage and
the relative statuses of the spouses
Myocardial mechanics in young adult patients with diabetes mellitus: Effects altered load, inotropic state and dynamic exercise
AbstractThe disease entity âdiabetic cardiomyopathyâ has been extensively described in young patients with diabetes in the absence of ischemic, hypertensive or valvular heart disease. The most convincing data have been a 30% to 40% incidence of decreased radionuclide angiographic left ventricular ejection fraction response to dynamic exercise. In the current study, the hypothesis was tested that this abnormal ejection fraction response was due to alterations in ventricular loading conditions or cardiac autonomic innervation (extrinsic factors), or both, rather than to abnormalities in intrinsic ventricular systolic fiber function (contractility).Twenty normotensive patients with diabetes (mean age 30 ± 5 years, mean duration 15 ± 6 years) and 20 age-matched normal subjects were studied. All patients with diabetes had a normal treadmill exercise tolerance test without evidence of myocardial ischemia. By radionuclide angiography, all normal subjects increased ejection fraction with exercise (62 ± 4% to 69 ± 6%; p < 0.001). In contrast, 11(55%) of 20 patients with diabetes maintained or increased ejection fraction with exercise (group 1; 62 ± 4% to 69 ± 6%; p < 0.001) and 9 (45%) of 20 showed an exercise-induced decrease (group 2; 73 ± 4% to 66 ± 6%; p < 0.001). No difference in the incidence of microangiopathy, as noted by funduscopic examination, was present between the diabetic groups. Despite the abnormal ejection fraction response to exercise in the group 2 patients with diabetes, all patients with diabetes had a nor response to afterload manipulation, normal baseline ventricular contractility as assessed by load- and heart rate-independent end-systolic indexes and normal contractile reserve as assessed with dobutamine challenge.Autonomic dysfunction did not explain the disparate results between the group 2 patients' radionuclide angiographic data and their load-independent tests of ventricular contractility and reserve. In addition, the high ejection fraction at rest in group 2 patients (73±4% versus 62 ± 4% for normal subjects; p < 0.001) was not related to the abnormal tests of autonomic function. Thus, when left ventricular systolic performance was assessed by load- and rate-independent indexes, there was no evidence for cardiomyopathy in young adult patients with diabetes who have normal blood nressure and no ischemie heart disease
Switching from linear to macrocyclic gadoliniumâbased contrast agents halts the relative T 1 âWeighted signal increase in deep gray matter of children with brain tumors: A retrospective study
BackgroundStudies have shown signal intensity (SI) changes in the brains of children exposed to repeated doses of a gadoliniumâbased contrast agent (GBCA).HypothesisThe trajectory of changes in relative dentate nucleus (DN) and globus pallidus (GP) SI in children receiving multiple doses of GBCA will alter when switched from linear to macrocyclic agents.Study TypeRetrospective longitudinal.PopulationThirtyâfive children, age range 0.5â17.0 years, undergoing brain tumor followâup between 2006 and 2017.Field Strength/SequenceUnenhanced T1WI, serial scans at both 1.5T and 3T.AssessmentRegions of interest were drawn on DN, GP, and SIs normalized to middle cerebellar peduncle (DN/MCP) and cerebral white matter (GP/CWM), respectively. A change in SI ratios as a function of dose (slope gradient) calculated according to the type of contrast agent received: linear only, macrocyclic only, or switchover from linear to macrocyclic. For the latter, gradients were compared before and after switchover. The effect of anticancer treatment on slope gradient was tested.Statistical TestsOneâsample tâtest or MannâWhitney Uâtest for slope gradients differing from zero. Independent samples tâtests to compare slope gradient groups. Paired sample tâtests to compare slope gradients before and after switchover.ResultsA significant (P < 0.05) increase in SI ratio was observed following multiple doses of linear but not macrocyclic agents: mean percentage increase per dose in SI was 0.063% vs. â0.034% for DN/MCP, and 0.078% vs. 0.004% for GP/CWM ratios. A significant (P < 0.05) change of SI trajectory in the DN/MCP ratio was demonstrated when switching from a linear to macrocyclic agent. There was no difference in SI trajectory between patients who had anticancer therapies and those who did not, DN/MCP P = 0.740; GP/BWM P = 0.694.Data ConclusionSwitching from linear to macrocyclic gadoliniumâbased contrast agents seems to halt the relative T1 signal increase in deep gray matter in children. Anticancer treatments appeared to have no impact on the trajectory of T1 SI
Serial MR diffusion to predict treatment response in high-grade pediatric brain tumors: a comparison of regional and voxel-based diffusion change metrics
Background
Assessment of treatment response by measuring tumor size is known to be a late and potentially confounded response index. Serial diffusion MRI has shown potential for allowing earlier and possibly more reliable response assessment in adult patients, with limited experience in clinical settings and in pediatric brain cancer. We present a retrospective study of clinical MRI data in children with high-grade brain tumors to assess and compare the values of several diffusion change metrics to predict treatment response.
Methods
Eighteen patients (age range, 1.9â20.6 years) with high-grade brain tumors and serial diffusion MRI (pre- and posttreatment interval range, 1â16 weeks posttreatment) were identified after obtaining parental consent. The following diffusion change metrics were compared with the clinical response status assessed at 6 months: (1) regional change in absolute and normalized apparent diffusivity coefficient (ADC), (2) voxel-based fractional volume of increased (fiADC) and decreased ADC (fdADC), and (3) a new metric based on the slope of the first principal component of functional diffusion maps (fDM).
Results
Responders (n = 12) differed significantly from nonresponders (n = 6) in all 3 diffusional change metrics demonstrating higher regional ADC increase, larger fiADC, and steeper slopes (P < .05). The slope method allowed the best response prediction (P < .01, η2 = 0.78) with a classification accuracy of 83% for a slope of 58° using receiver operating characteristic (ROC) analysis.
Conclusions
We demonstrate that diffusion change metrics are suitable response predictors for high-grade pediatric tumors, even in the presence of variable clinical diffusion imaging protocols
QuantiFERONÂź-TB gold in-tube performance for diagnosing active tuberculosis in children and adults in a high burden setting.
To determine whether QuantiFERONÂź-TB Gold In-Tube (QFT) can contribute to the diagnosis of active tuberculosis (TB) in children in a high-burden setting and to assess the performance of QFT and tuberculin skin test (TST) in a prospective cohort of TB suspect children compared to adults with confirmed TB in Tanzania. Sensitivity and specificity of QFT and TST for diagnosing active TB as well as indeterminate QFT rates and IFN-Îł levels were assessed in 211 TB suspect children in a Tanzanian district hospital and contrasted in 90 adults with confirmed pulmonary TB. Sensitivity of QFT and TST in children with confirmed TB was 19% (5/27) and 6% (2/31) respectively. In adults sensitivity of QFT and TST was 84% (73/87) and 85% (63/74). The QFT indeterminate rate in children and adults was 27% and 3%. Median levels of IFN-Îł were lower in children than adults, particularly children <2 years and HIV infected. An indeterminate result was associated with age <2 years but not malnutrition or HIV status. Overall childhood mortality was 19% and associated with an indeterminate QFT result at baseline. QFT and TST showed poor performance and a surprisingly low sensitivity in children. In contrast the performance in Tanzanian adults was good and comparable to performance in high-income countries. Indeterminate results in children were associated with young age and increased mortality. Neither test can be recommended for diagnosing active TB in children with immature or impaired immunity in a high-burden setting
Metrics and textural features of MRI diffusion to improve classification of pediatric posterior fossa tumors
BACKGROUND AND PURPOSE: Qualitative radiologic MR imaging review affords limited differentiation among types of pediatric posterior fossa brain tumors and cannot detect histologic or molecular subtypes, which could help to stratify treatment. This study aimed to improve current posterior fossa discrimination of histologic tumor type by using support vector machine classifiers on quantitative MR imaging features.
MATERIALS AND METHODS: This retrospective study included preoperative MRI in 40 children with posterior fossa tumors (17 medulloblastomas, 16 pilocytic astrocytomas, and 7 ependymomas). Shape, histogram, and textural features were computed from contrast-enhanced T2WI and T1WI and diffusivity (ADC) maps. Combinations of features were used to train tumor-type-specific classifiers for medulloblastoma, pilocytic astrocytoma, and ependymoma types in separation and as a joint posterior fossa classifier. A tumor-subtype classifier was also produced for classic medulloblastoma. The performance of different classifiers was assessed and compared by using randomly selected subsets of training and test data.
RESULTS: ADC histogram features (25th and 75th percentiles and skewness) yielded the best classification of tumor type (on average >95.8% of medulloblastomas, >96.9% of pilocytic astrocytomas, and >94.3% of ependymomas by using 8 training samples). The resulting joint posterior fossa classifier correctly assigned >91.4% of the posterior fossa tumors. For subtype classification, 89.4% of classic medulloblastomas were correctly classified on the basis of ADC texture features extracted from the Gray-Level Co-Occurence Matrix.
CONCLUSIONS: Support vector machineâbased classifiers using ADC histogram features yielded very good discrimination among pediatric posterior fossa tumor types, and ADC textural features show promise for further subtype discrimination. These findings suggest an added diagnostic value of quantitative feature analysis of diffusion MR imaging in pediatric neuro-oncology
Classification of paediatric brain tumours by diffusion weighted imaging and machine learning
To determine if apparent diffusion coefficients (ADC) can discriminate between posterior fossa brain tumours on a multicentre basis. A total of 124 paediatric patients with posterior fossa tumours (including 55 Medulloblastomas, 36 Pilocytic Astrocytomas and 26 Ependymomas) were scanned using diffusion weighted imaging across 12 different hospitals using a total of 18 different scanners. Apparent diffusion coefficient maps were produced and histogram data was extracted from tumour regions of interest. Total histograms and histogram metrics (mean, variance, skew, kurtosis and 10th, 20th and 50th quantiles) were used as data input for classifiers with accuracy determined by tenfold cross validation. Mean ADC values from the tumour regions of interest differed between tumour types, (ANOVA Pâ<â0.001). A cut off value for mean ADC between Ependymomas and Medulloblastomas was found to be of 0.984âĂâ10-3 mm2 s-1 with sensitivity 80.8% and specificity 80.0%. Overall classification for the ADC histogram metrics were 85% using NaĂŻve Bayes and 84% for Random Forest classifiers. The most commonly occurring posterior fossa paediatric brain tumours can be classified using Apparent Diffusion Coefficient histogram values to a high accuracy on a multicentre basis
MRI and Molecular Characterization of Pediatric High-Grade Midline Thalamic Gliomas: The HERBY Phase II Trial
Background: Diffuse midline gliomas (DMG) are characterized by a high incidence of H3 K27 mutations and poorer outcome. The HERBY trial has provided one of the largest cohorts of pediatric DMGs with available radiologic, histologic-genotypic, and survival data. / Purpose: To define MRI and molecular characteristics of DMG. / Materials and Methods: This study is a secondary analysis of a prospective trial (HERBY; ClinicalTrials.gov identifier, NCT01390948) undertaken between October 2011 and February 2016. Among 121 HERBY participants, 50 had midline nonpontine-based tumors. Midline high-grade gliomas were reclassified into DMG H3 K27 mutant, H3 wild type with enhancer of zest homologs inhibitory protein overexpression, epidermal growth factor receptormutant, or not otherwise stated. The epicenter of each tumor and other radiologic characteristics were ascertained from MRI and correlated with the new subtype classification, histopathologic characteristics, surgical extent, and outcome parameters. Kaplan-Meier curves and log-rank tests were applied to determine and describe survival differences between groups. / Results: There were 42 participants (mean age, 12 years ± 4 [SD]; 23 girls) with radiologically evaluable thalamic-based DMG. Eighteen had partial thalamic involvement (12 thalamopulvinar, six anteromedial), 10 involved a whole thalamus, nine had unithalamic tumors with diffuse contiguous extension, and five had bithalamic tumors (two symmetric, three partial). Twenty-eight participants had DMG H3 K27 mutant tumors; there were no differences in outcome compared with other DMGs (n = 4). Participants who underwent major debulking or total or near-total resection had longer overall survival (OS): 18.5 months vs 11.4 months (P = .02). Enrolled participants who developed leptomeningeal metastatic dissemination before starting treatment had worse outcomes (event-free survival, 2.9 months vs 8.0 months [P = .02]; OS, 11.4 months vs 18.5 months [P = .004]). / Conclusion: Thalamic involvement of diffuse midline gliomas ranged from localized partial thalamic to holo- or bithalamic with diffuse contiguous spread and had poor outcomes, irrespective of H3 K27 subtype alterations. Leptomeningeal dissemination and less than 50% surgical resection were adverse risk factors for survival. / Clinical trial registration no. NCT0139094
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