1,444 research outputs found
Direct method for detection and characterization of cell surface receptors for insulin by means of 125I-labeled autoantibodies against the insulin receptor.
SNIP/p140Cap mRNA expression is an unfavourable prognostic factor in breast cancer and is not expressed in normal breast tissue
The prevalence and clinical relevance of SNIP/p140Cap has not been extensively investigated. Here SNIP/p140Cap mRNA expression was studied in 103 breast tumour biopsies, where it was detected in ∼37% of tumour specimens, but not in any normal breast specimens. Expression correlated significantly with unfavourable overall survival. This suggests that SNIP/p140Cap may be a useful diagnostic and prognostic marker for breast cancer and its expression in breast cancer, but not in normal breast tissue, suggests that it may have potential as a therapeutic target
Biomarker testing in MCI patients—deciding who to test
BACKGROUND: We aimed to derive an algorithm to define the optimal proportion of patients with mild cognitive impairment (MCI) in whom cerebrospinal fluid (CSF) testing is of added prognostic value.
METHODS: MCI patients were selected from the Amsterdam Dementia Cohort (n = 402). Three-year progression probabilities to dementia were predicted using previously published models with and without CSF data (amyloid-beta1-42 (Abeta), phosphorylated tau (p-tau)). We incrementally augmented the proportion of patients undergoing CSF, starting with the 10% patients with prognostic probabilities based on clinical data around the median (percentile 45–55), until all patients received CSF. The optimal proportion was defined as the proportion where the stepwise algorithm showed similar prognostic discrimination (Harrell’s C) and accuracy (three-year Brier scores) compared to CSF testing of all patients. We used the BioFINDER study (n = 221) for validation.
RESULTS: The optimal proportion of MCI patients to receive CSF testing selected by the stepwise approach was 50%. CSF testing in only this proportion improved the performance of the model with clinical data only from Harrell’s C = 0.60, Brier = 0.198 (Harrell’s C = 0.61, Brier = 0.197 if the information on magnetic resonance imaging was available) to Harrell’s C = 0.67 and Brier = 0.190, and performed similarly to a model in which all patients received CSF testing. Applying the stepwise approach in the BioFINDER study would again select half of the MCI patients and yielded robust results with respect to prognostic performance.
INTERPRETATION:
CSF biomarker testing adds prognostic value in half of the MCI patients. As such, we achieve a CSF saving recommendation while simultaneously retaining optimal prognostic accuracy
Transgenic amplification of glucocorticoid action in adipose tissue causes high blood pressure in mice
Obesity is closely associated with the metabolic syndrome, a combination of disorders including insulin resistance, diabetes, dyslipidemia, and hypertension. A role for local glucocorticoid reamplification in obesity and the metabolic syndrome has been suggested. The enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) regenerates active cortisol from inactive 11-keto forms, and aP2-HSD1 mice with relative transgenic overexpression of this enzyme in fat cells develop visceral obesity with insulin resistance and dyslipidemia. Here we report that aP2-HSD1 mice also have high arterial blood pressure (BP). The mice have increased sensitivity to dietary salt and increased plasma levels of angiotensinogen, angiotensin II, and aldosterone. This hypertension is abolished by selective angiotensin II receptor AT-1 antagonist at a low dose that does not affect BP in non-Tg littermates. These findings suggest that activation of the circulating renin-angiotensin system (RAS) develops in aP2-HSD1 mice. The long-term hypertension is further reflected by an appreciable hypertrophy and hyperplasia of the distal tubule epithelium of the nephron, resembling salt-sensitive or angiotensin II–mediated hypertension. Taken together, our findings suggest that overexpression of 11β-HSD1 in fat is sufficient to cause salt-sensitive hypertension mediated by an activated RAS. The potential role of adipose 11β-HSD1 in mediating critical features of the metabolic syndrome extends beyond obesity and metabolic complications to include the most central cardiovascular feature of this disorder
?-Tanycytes of the adult hypothalamic third ventricle include distinct populations of FGF-responsive neural progenitors
Emerging evidence suggests that new cells, including neurons, can be generated within the adult hypothalamus, suggesting the existence of a local neural stem/progenitor cell niche. Here, we identify a-tanycytes as key components of a hypothalamic niche in the adult mouse. Long-term lineage tracing in vivo using a GLAST::CreERT2 conditional driver indicates that α-tanycytes are self-renewing cells that constitutively give rise to new tanycytes, astrocytes and sparse numbers of neurons. In vitro studies demonstrate that α-tanycytes, but not β-tanycytes or parenchymal cells, are neurospherogenic. Distinct subpopulations of α-tanycytes exist, amongst which only GFAP-positive dorsal α2-tanycytes possess stem-like neurospherogenic activity. Fgf-10 and Fgf-18 are expressed specifically within ventral tanycyte subpopulations; α-tanycytes require fibroblast growth factor signalling to maintain their proliferation ex vivo and elevated fibroblast growth factor levels lead to enhanced proliferation of a-tanycytes in vivo. Our results suggest that α-tanycytes form the critical component of a hypothalamic stem cell niche, and that local fibroblast growth factor signalling governs their proliferation. © 2013 Macmillan Publishers Limited. All rights reserved
Intestinal stem cells lacking the Math1 tumour suppressor are refractory to Notch inhibitors
Intestinal cells are constantly produced from a stem cell reservoir that gives rise to proliferating transient amplifying cells, which subsequently differentiate into one of the four principal cell types. Signalling pathways, including the Notch signalling pathway, coordinate these differentiation processes and their deregulation may cause cancer. Pharmacological inhibition through γ-secretase inhibitors or genetic inactivation of the Notch signalling pathway results in the complete loss of proliferating crypt progenitors due to their conversion into post-mitotic goblet cells. The basic helix–loop–helix transcription factor Math1 is essential for intestinal secretory cell differentiation. Because of the critical roles of both Math1 and Notch signalling in intestinal homeostasis and neoplastic transformation, we sought to determine the genetic hierarchy regulating the differentiation of intestinal stem cells into secretory cells. In this paper, we demonstrate that the conversion of intestinal stem cells into goblet cells upon inhibition of the Notch signalling pathway requires Math1
Brain atrophy accelerates cognitive decline in cerebral small vessel disease: The LADIS study
Objective: To examine the independent contributions and combined interactions of medial temporal lobe atrophy (MTA), cortical and subcortical atrophy, and white matter lesion (WML) volume in longitudinal cognitive performance. Methods: A total of 477 subjects with age-relatedWMLwere evaluated with brain MRI and annual neuropsychological examinations in 3-year follow-up. Baseline MRI determinants of cognitive decline were analyzed with linear mixed models controlling for multiple confounders. Results: MTA and subcortical atrophy predicted significantly steeper rate of decline in global cognitive measures as well as compound scores for psychomotor speed, executive functions, and memory after adjusting for age, gender, education, lacunes/infarcts, and WML volume. Cortical atrophy independently predicted decline in psychomotor speed. WML volume remained significantly associated with cognitive decline even after controlling for the atrophy scores. Moreover, significant synergistic interactions were found between WML and atrophy measures in overall cognitive performance across time and the rate of cognitive decline. Synergistic effects were also observed between baseline lacunar infarcts and all atrophy measures on change in psychomotor speed. The main results remained robust after exclusion of subjects with clinical stroke or incident dementia, and after additional adjustments for progression of WML and lacunes. Conclusions: Brain atrophy and WML are independently related to longitudinal cognitive decline in small vessel disease. MTA, subcortical, and cortical atrophy seem to potentiate the effect ofWML and lacunes on cognitive decline
Location of lacunar infarcts correlates with cognition in a sample of non-disabled subjects with age-related white-matter changes: the LADIS study
Objectives: In cerebral small vessel disease, whitematter hyperintensities (WMH) and lacunes are both related to cognition. Still, their respective contribution in older people remains unclear. The purpose of this study is to assess the topographic distribution of lacunes and determine whether it has an impact on cognitive functions in a sample of non-disabled patients with age-related white-matter changes. Methods: Data were drawn from the baseline evaluation of the LADIS (Leucoaraioisis and Disability study) cohort of non-disabled subjects beyond 65 years of age. The neuropsychological evaluation was based on the Mini Mental Status Examination (MMSE), a modified Alzheimer Diseases Assessment Scale for global cognitive functions, and compound Z scores for memory, executive functions, speed and motor control. WMH were rated according to the Fazekas scale; the number of lacunes was assessed in the following areas: lobar white matter, putamen/ pallidum, thalamus, caudate nucleus, internal/external capsule, infratentorial areas. An analysis of covariance was performed after adjustment for possible confounders. Results: Among 633 subjects, 47% had at least one lacune (31% at least one within basal ganglia). The presence of lacunes in the thalamus was associated with lower scores of MMSE (b=20.61; p=0.043), and worse compound scores for speed and motor control (b=20.25; p=0.006), executive functions (b=20.19; p=0.022) independently of the cognitive impact of WMH. There was also a significant negative association between the presence of lacunes in putamen/ pallidum and the memory compound Z score (b=20.13; p=0.038). By contrast, no significant negative association was found between cognitive parameters and the presence of lacunes in internal capsule, lobar white matter and caudate nucleus. Conclusion: In non-disabled elderly subjects with leucoaraisosis, the location of lacunes within subcortical grey matter is a determinant of cognitive impairment, independently of the extent of WMH
Differential trajectories of hypometabolism across cognitively-defined Alzheimer’s disease subgroups
Disentangling biologically distinct subgroups of Alzheimer’s disease (AD) may facilitate a deeper understanding of the neurobiology underlying clinical heterogeneity. We employed longitudinal [18F]FDG-PET standardized uptake value ratios (SUVRs) to map hypometabolism across cognitively-defined AD subgroups. Participants were 384 amyloid-positive individuals with an AD dementia diagnosis from ADNI who had a total of 1028 FDG-scans (mean time between first and last scan: 1.6 ± 1.8 years). These participants were categorized into subgroups on the basis of substantial impairment at time of dementia diagnosis in a specific cognitive domain relative to the average across domains. This approach resulted in groups of AD-Memory (n = 135), AD-Executive (n = 8), AD-Language (n = 22), AD-Visuospatial (n = 44), AD-Multiple Domains (n = 15) and AD-No Domains (for whom no domain showed substantial relative impairment; n = 160). Voxelwise contrasts against controls revealed that all AD-subgroups showed progressive hypometabolism compared to controls across temporoparietal regions at time of AD diagnosis. Voxelwise and regions-of-interest (ROI)-based linear mixed model analyses revealed there were also subgroup-specific hypometabolism patterns and trajectories. The AD-Memory group had more pronounced hypometabolism compared to all other groups in the medial temporal lobe and posterior cingulate, and faster decline in metabolism in the medial temporal lobe compared to AD-Visuospatial. The AD-Language group had pronounced lateral temporal hypometabolism compared to all other groups, and the pattern of metabolism was also more asymmetrical (left < right) than all other groups. The AD-Visuospatial group had faster decline in metabolism in parietal regions compared to all other groups, as well as faster decline in the precuneus compared to AD-Memory and AD-No Domains. Taken together, in addition to a common pattern, cognitively-defined subgroups of people with AD dementia show subgroup-specific hypometabolism patterns, as well as differences in trajectories of metabolism over time. These findings provide support to the notion that cognitively-defined subgroups are biologically distinct
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