198 research outputs found
A dohányzás és az anyagi helyzet összefüggése serdülőkori és felnőttkori terhesség esetén
INTRODUCTION: Smoking occurs frequently during pregnancy, thereby putting mother and child at health risks. Low socio-economic status is a risk factor for smoking. AIM: To investigate the relationship between smoking and low income in teenage and adult pregnancy, which is an important measure of poor socioeconomic status. METHOD: The authors used subject-level data from the US NSDUH database, which contains information on pregnancies and smoking. RESULTS: Teenage pregnancy is associated with higher, whereas adult pregnancy with lower prevalence of smoking, compared to the age-matched female population. The association between income and smoking is age-dependent. Among adults there is an inverse relationship (high income -- low-risk of smoking), while in teenage pregnancy smoking increases with income. CONCLUSIONS: To investigate in teenage and adult pregnancy the relationship between smoking and low income, which is an important measure of poor socio-economic status. Higher socioeconomic status may be associated with risky behaviour, thereby increasing both the risk of smoking and early pregnancy
Development and Screening of Contrast Agents for In Vivo Imaging of Parkinson’s Disease
Purpose: The goal was to identify molecular imaging probes that would enter the brain, selectively bind to Parkinson’s disease (PD) pathology, and be detectable with one or more imaging modalities.
Procedure: A library of organic compounds was screened for the ability to bind hallmark pathology in human Parkinson’s and Alzheimer’s disease tissue, alpha-synuclein oligomers and inclusions in two cell culture models, and alpha-synuclein aggregates in cortical neurons of a transgenic mouse model. Finally, compounds were tested for blood–brain barrier permeability using intravital microscopy.
Results: Several lead compounds were identified that bound the human PD pathology, and some showed selectivity over Alzheimer’s pathology. The cell culture models and transgenic mouse models that exhibit alpha-synuclein aggregation did not prove predictive for ligand binding. The compounds had favorable physicochemical properties, and several were brain permeable.
Conclusions: Future experiments will focus on more extensive evaluation of the lead compounds as PET ligands for clinical imaging of PD pathology
Apolipoprotein E: Isoform Specific Differences in Tertiary Structure and Interaction with Amyloid-β in Human Alzheimer Brain
We applied a novel application of FLIM-FRET to in situ measurement and quantification of protein interactions to explore isoform specific differences in Aβ-ApoE interaction and ApoE tertiary conformation in senile plaques in human Alzheimer brain. ApoE3 interacts more closely with Aβ than ApoE4, but a greater proportion of Aβ molecules within plaques are decorated with ApoE4 than ApoE3, lending strong support to the hypothesis that isoform specific differences in ApoE are linked with Aβ deposition. We found an increased number of ApoE N-terminal fragments in ApoE4 plaques, consistent with the observation that ApoE4 is more easily cleaved than ApoE3. In addition, we measured a small but significant isoform specific difference in ApoE domain interaction. Based on our in situ data, supported by traditional biochemical data, we propose a pathway by which isoform specific conformational differences increase the level of cleavage at the hinge region of ApoE4, leading to a loss of ApoE function to mediate clearance of Aβ and thereby increase the risk of AD for carriers of the APOEε4 allele
In vivo imaging reveals dissociation between caspase activation and acute neuronal death in tangle-bearing neurons
Impaired spine stability underlies plaque-related spine loss in an Alzheimer's disease mouse model
Dendritic spines, the site of most excitatory synapses in the brain, are lost in Alzheimer’s disease and in related mouse models, undoubtedly contributing to cognitive dysfunction. We hypothesized that spine loss results from plaque-associated alterations of spine stability, causing an imbalance in spine forma-tion and elimination. To investigate effects of plaques on spine stability in vivo, we observed cortical neu-rons using multiphoton microscopy in a mouse model of amyloid pathology before and after extensive plaque deposition. We also observed age-matched non-transgenic mice to study normal effects of aging on spine plasticity. We found that spine density and struc-tural plasticity are maintained during normal aging. Tg2576 mice had normal spine density and plasticity before plaques appeared, but after amyloid pathology is established, severe disruptions were observed. In con-trol animals, spine formation and elimination were equivalent over 1 hour of observation (5 % of observed spines), resulting in stable spine density. However, in aged Tg2576 mice spine elimination increased, specifi-cally in the immediate vicinity of plaques. Spine forma-tion was unchanged, resulting in spine loss. These data show a small population of rapidly changing spines in adult and even elderly mouse cortex; further, in the vicinity of amyloid plaques, spine stability is markedly impaired leading to loss of synaptic structural in
Persistent cAMP-Signals Triggered by Internalized G-Protein–Coupled Receptors
Real-time monitoring of G-protein-coupled receptor (GPCR) signaling in native cells suggests that the receptor for thyroid stimulating hormone remains active after internalization, challenging the current model for GPCR signaling
Neurofibrillary tangle-bearing neurons are functionally integrated in cortical circuits in vivo
Alzheimer's disease (AD) is pathologically characterized by the deposition of extracellular amyloid-β plaques and intracellular aggregation of tau protein in neurofibrillary tangles (NFTs) (1, 2). Progression of NFT pathology is closely correlated with both increased neurodegeneration and cognitive decline in AD (3) and other tauopathies, such as frontotemporal dementia (4, 5). The assumption that mislocalization of tau into the somatodendritic compartment (6) and accumulation of fibrillar aggregates in NFTs mediates neurodegeneration underlies most current therapeutic strategies aimed at preventing NFT formation or disrupting existing NFTs (7, 8). Although several disease-associated mutations cause both aggregation of tau and neurodegeneration, whether NFTs per se contribute to neuronal and network dysfunction in vivo is unknown (9). Here we used awake in vivo two-photon calcium imaging to monitor neuronal function in adult rTg4510 mice that overexpress a human mutant form of tau (P301L) and develop cortical NFTs by the age of 7–8 mo (10). Unexpectedly, NFT-bearing neurons in the visual cortex appeared to be completely functionally intact, to be capable of integrating dendritic inputs and effectively encoding orientation and direction selectivity, and to have a stable baseline resting calcium level. These results suggest a reevaluation of the common assumption that insoluble tau aggregates are sufficient to disrupt neuronal function
In Vivo Detection of Amyloid-β Deposits Using Heavy Chain Antibody Fragments in a Transgenic Mouse Model for Alzheimer's Disease
This study investigated the in vivo properties of two heavy chain antibody fragments (VHH), ni3A and pa2H, to differentially detect vascular or parenchymal amyloid-β deposits characteristic for Alzheimer's disease and cerebral amyloid angiopathy. Blood clearance and biodistribution including brain uptake were assessed by bolus injection of radiolabeled VHH in APP/PS1 mice or wildtype littermates. In addition, in vivo specificity for Aβ was examined in more detail with fluorescently labeled VHH by circumventing the blood-brain barrier via direct application or intracarotid co-injection with mannitol. All VHH showed rapid renal clearance (10–20 min). Twenty-four hours post-injection 99mTc-pa2H resulted in a small yet significant higher cerebral uptake in the APP/PS1 animals. No difference in brain uptake were observed for 99mTc-ni3A or DTPA(111In)-pa2H, which lacked additional peptide tags to investigate further clinical applicability. In vivo specificity for Aβ was confirmed for both fluorescently labeled VHH, where pa2H remained readily detectable for 24 hours or more after injection. Furthermore, both VHH showed affinity for parenchymal and vascular deposits, this in contrast to human tissue, where ni3A specifically targeted only vascular Aβ. Despite a brain uptake that is as yet too low for in vivo imaging, this study provides evidence that VHH detect Aβ deposits in vivo, with high selectivity and favorable in vivo characteristics, making them promising tools for further development as diagnostic agents for the distinctive detection of different Aβ deposits
ApoE Receptor 2 Regulates Synapse and Dendritic Spine Formation
Apolipoprotein E receptor 2 (ApoEr2) is a postsynaptic protein involved in long-term potentiation (LTP), learning, and memory through unknown mechanisms. We examined the biological effects of ApoEr2 on synapse and dendritic spine formation-processes critical for learning and memory.In a heterologous co-culture synapse assay, overexpression of ApoEr2 in COS7 cells significantly increased colocalization with synaptophysin in primary hippocampal neurons, suggesting that ApoEr2 promotes interaction with presynaptic structures. In primary neuronal cultures, overexpression of ApoEr2 increased dendritic spine density. Consistent with our in vitro findings, ApoEr2 knockout mice had decreased dendritic spine density in cortical layers II/III at 1 month of age. We also tested whether the interaction between ApoEr2 and its cytoplasmic adaptor proteins, specifically X11α and PSD-95, affected synapse and dendritic spine formation. X11α decreased cell surface levels of ApoEr2 along with synapse and dendritic spine density. In contrast, PSD-95 increased cell surface levels of ApoEr2 as well as synapse and dendritic spine density.These results suggest that ApoEr2 plays important roles in structure and function of CNS synapses and dendritic spines, and that these roles are modulated by cytoplasmic adaptor proteins X11α and PSD-95
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