Viability and Contractility of Rat Brain Pericytes in Conditions That Mimic Stroke; an Study.

Reopening of the cerebral artery after occlusion often results in "no-reflow" that has been attributed to the death and contraction () of pericytes. Since this hypothesis still needs to be confirmed, we explored the effects of oxygen glucose deprivation (OGD) on viability and cell death of primary rat pericytes, in the presence or absence of neurovascular unit-derived cytokines. Two morphodynamic parameters, single cell membrane mobility (SCMM) and fractal dimension (D), were used to analyze the cell contractions and membrane complexity before and after OGD.

Differential Release of Exocytosis Marker Dyes Indicates Stimulation-Dependent Regulation of Synaptic Activity.

There is a general consensus that synaptic vesicular release by a full collapse process is the primary machinery of synaptic transmission. However, competing view suggests that synaptic vesicular release operates via a kiss-and-run mechanism. By monitoring the release dynamics of a synaptic vesicular marker, FM1-43 from individual synapses in hippocampal neurons, we found evidence that the release of synaptic vesicle was delayed by several seconds after the start of field stimulation.

Quantitative Determination of Cellular-and Neurite Motility Speed in Dense Cell Cultures.

Mobility quantification of single cells and cellular processes in dense cultures is a challenge, because single cell tracking is impossible. We developed a software for cell structure segmentation and implemented 2 algorithms to measure motility speed. Complex algorithms were tested to separate cells and cellular components, an important prerequisite for the acquisition of meaningful motility data.

Multidimensional plasma protein separation technique for identification of potential Alzheimer's disease plasma biomarkers: a pilot study.

Neurochemical differential diagnosis between Alzheimer's disease and other dementias is currently based on CSF biomarkers. Here, we report a method by which potential biomarkers can be identified in blood. Blood plasma samples from seven well-characterized Alzheimer's patients and seven non-Alzheimer's patients were subjected to a multi-dimensional protein separation procedure.

Systematic heterogeneity of fractional vesicle pool sizes and release rates of hippocampal synapses.

Hippocampal neurons in tissue culture develop functional synapses that exhibit considerable variation in synaptic vesicle content (20-350 vesicles). We examined absolute and fractional parameters of synaptic vesicle exocytosis of individual synapses. Their correlation to vesicle content was determined by activity-dependent discharge of FM-styryl dyes.

Pre-aggregated Aβ1-42 peptide increases tau aggregation and hyperphosphorylation after short-term application.

Neuritic amyloid plaques and neurofibrillary tangles, consisting of hyperphosphorylated tau protein, are the hallmarks of Alzheimer disease. It is not clear so far, how both structures are functionally and physiologically connected. We have investigated the role of Aβ1-42 on hyperphosphorylation and aggregation of tau in SY5Y cells by transfection and overexpression with two tau constructs, a shortened wildtype tau (2N4R) and a point mutation tau (P301L), found in fronto-temporal dementia.

Synapse clusters are preferentially formed by synapses with large recycling pool sizes.

Synapses are distributed heterogeneously in neural networks. The relationship between the spatial arrangement of synapses and an individual synapse's structural and functional features remains to be elucidated. Here, we examined the influence of the number of adjacent synapses on individual synaptic recycling pool sizes.

Distinct intracellular vesicle transport mechanisms are selectively modified by spastin and spastin mutations.

Spastin is a microtubule severing ATPase that regulates intracellular and axonal transport of vesicles. Intracellular vesicle trafficking was analyzed in differentiated SH-SY5Y-neuroblastoma cells, transfected with spastin wild-type and three spastin mutations (ΔN, K388R, S44L) to investigate spastin-mediated effects on the velocity of vesicles, stained with LysoTracker Red®. The vesicle velocity varied considerably between mutations and detailed analysis revealed up to five distinct velocity classes.

Fluoxetine prevents stimulation-dependent fatigue of synaptic vesicle exocytosis in hippocampal neurons.

Effects of the antidepressant fluoxetine on stimulation-dependent synaptic vesicle exocytosis were examined in cultured primary hippocampal neurons. Synaptic vesicles were fluorescently labeled in vitro with FM1-43, washed and subsequently destained in two consecutive cycles. Exocytosis was triggered by electric field stimulation and imaged by fluorescence microscopy.

Lipophilic cationic drugs increase the permeability of lysosomal membranes in a cell culture system.

Lysosomes accumulate many drugs several fold higher compared to their extracellular concentration. This mechanism is believed to be responsible for many pharmacological effects. So far, uptake and release kinetics are largely unknown and interactions between concomitantly administered drugs often provoke mutual interference.

The role of ceramide in major depressive disorder.

Major depression is a severe mood disorder with a lifetime prevalence of more than 10%. The pharmacokinetic hypothesis claims that a slow accumulation of antidepressant drugs by acid trapping mainly into lysosomes is responsible for the therapeutic latency and that a lysosomal target mediates the antidepressant effects. The lysosomal lipid metabolizing enzyme acid sphingomyelinase (ASM) cleaves sphingomyelin into ceramide and phosphorylcholine.

Antidepressant drugs modulate growth factors in cultured cells.

Background: Different classes of antidepressant drugs are used as a treatment for depression by activating the catecholinergic system. In addition, depression has been associated with decrease of growth factors, which causes insufficient axonal sprouting and reduced neuronal damage repair. In this study, antidepressant treatments are analyzed in a cell culture system, to study the modulation of growth factors.

Urea-based two-dimensional electrophoresis of beta-amyloid peptides in human plasma: evidence for novel Abeta species.

The detailed analysis of beta-amyloid (Abeta) peptides in human plasma is still hampered by the limited sensitivity of available mass spectrometric methods and the lack of appropiate ELISAs to measure Abeta peptides other than Abeta(1-38), Abeta(1-40), and Abeta(1-42). By combining high-yield Abeta immuno- precipitation (IP), IEF, and urea-based Abeta-SDS-PAGE-immunoblot, at least 30 Abeta-immuno-reactive spots were detected in human plasma samples as small as 1.6 mL.

Light-induced exocytosis in cell development and differentiation.

Calcium-dependent exocytosis of fluorescently labeled single secretory vesicles in PC12 cells and primary embryonic telencephalon cells can be triggered by illumination with visible light and imaged by TIRF or epifluorescence microscopy. Opsin 3 was identified by quantitative PCR expression analysis as the putative light receptor molecule for light-induced exocytosis. In primary chicken telencephalon cells, light-induced exocytosis is restricted to a specific period during embryonic development, and involves fusion of rather large vesicles.

Staurosporine restores GTPgammaS induced block of rapid endocytosis in chromaffin cells.

Fast capacitance measurements demonstrated that chromaffin cells retrieve membrane by several kinetically different pathways. Here, we show that rapid endocytosis is blocked and slow endocytosis reduced by intracellular application of GTPgammaS, an activator of G-proteins, but not by the competitive blocker GDPbetaS. The inhibition of rapid endocytosis by GTPgammaS can be restored with GDPbetaS or staurosporine completely.

Neurochemical diagnosis of Alzheimer's dementia by CSF Abeta42, Abeta42/Abeta40 ratio and total tau.

Cerebrospinal fluid (CSF) concentrations of amyloid beta peptides ending at positions 42 and 40 (Abeta42 and Abeta40, respectively), and total tau (tTau) protein were measured by ELISA in order to compare their accuracy in discriminating patients with Alzheimer's disease (AD, n = 22), non-Alzheimer dementia (nAD, n = 11) and control subjects (CON, n=35). As compared to the other groups, the concentrations of Abeta42 and tTau were decreased (P<0.001) and increased (P<0.

Patch-clamp capacitance measurements: new insights into the endocytic uptake of transferrin.

Since its introduction by Neher and Sakmann in 1976 the patch-clamp technique has been extensively used to study processes such as signalling and synaptic transmission, but also for monitoring endo- and exocytosis. Since biological membranes behave like electrical capacitors high-resolution measurements of membrane capacitance allow detection of small changes in membrane surface area that accompany exocytosis and endocytosis. We here describe our recent work on patch-clamp capacitance measurements in stably transfected HeLa cells expressing HFE, the hereditary hemochromatosis gene product, under the control of a tetracycline-sensitive promotor.

Are obese adolescents and young adults at higher risk for mental disorders? A community survey.

Objective: Associations between body mass index (BMI) and mental disorders meeting Axis-I diagnoses according to the Diagnostic and Statistical Manual for Mental Disorders IV (DSM-IV) were investigated in The Early Developmental Stages of Psychopathology Study in a large population-based sample, which included adolescents and young adults of both genders for the first time.

Research Methods And Procedures: A total of 3021 German subjects ranging from 14 to 24 years of age were assessed for specific DSM-IV diagnoses derived from a modified version of the standardized Composite International Diagnostic Interview, and general psychological disturbances, using the Symptom Checklist-90-Revised. BMI percentiles for age and gender were calculated to avoid systematic bias in the BMI distribution resulting from the young age range represented in the sample.

Regulation of transferrin-induced endocytosis by wild-type and C282Y-mutant HFE in transfected HeLa cells.

The hereditary hemochromatosis protein HFE is known to complex with the transferrin receptor; however, its function regarding endocytosis of transferrin is unclear. We performed patch-clamp capacitance measurements in transfected HeLa cells carrying wild-type or C282Y-mutant HFE cDNA under the control of a tetracycline-sensitive promoter. Whole cell experiments in cells with suppressed expression of wild-type HFE revealed a decrease in membrane capacitance, reflecting predominance of endocytosis in the presence of transferrin.