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1.
J Neurosci ; 43(6): 885-901, 2023 02 08.
Article in English | MEDLINE | ID: mdl-36535770

ABSTRACT

Memory formation and maintenance is a dynamic process involving the modulation of the actin cytoskeleton at synapses. Understanding the signaling pathways that contribute to actin modulation is important for our understanding of synapse formation and function, as well as learning and memory. Here, we focused on the importance of the actin regulator, noncatalytic region of tyrosine kinase adaptor protein 1 (NCK1), in hippocampal dependent behaviors and development. We report that male mice lacking NCK1 have impairments in both short-term and working memory, as well as spatial learning. Additionally, we report sex differences in memory impairment showing that female mice deficient in NCK1 fail at reversal learning in a spatial learning task. We find that NCK1 is expressed in postmitotic neurons but is dispensable for neuronal proliferation and migration in the developing hippocampus. Morphologically, NCK1 is not necessary for overall neuronal dendrite development. However, neurons lacking NCK1 have lower dendritic spine and synapse densities in vitro and in vivo EM analysis reveal increased postsynaptic density (PSD) thickness in the hippocampal CA1 region of NCK1-deficient mice. Mechanistically, we find the turnover of actin-filaments in dendritic spines is accelerated in neurons that lack NCK1. Together, these findings suggest that NCK1 contributes to hippocampal-dependent memory by stabilizing actin dynamics and dendritic spine formation.SIGNIFICANCE STATEMENT Understanding the molecular signaling pathways that contribute to memory formation, maintenance, and elimination will lead to a better understanding of the genetic influences on cognition and cognitive disorders and will direct future therapeutics. Here, we report that the noncatalytic region of tyrosine kinase adaptor protein 1 (NCK1) adaptor protein modulates actin-filament turnover in hippocampal dendritic spines. Mice lacking NCK1 show sex-dependent deficits in hippocampal memory formation tasks, have altered postsynaptic densities, and reduced synaptic density. Together, our work implicates NCK1 in the regulation of actin cytoskeleton dynamics and normal synapse development which is essential for memory formation.


Subject(s)
Actins , Dendritic Spines , Animals , Female , Male , Mice , Actins/metabolism , Dendritic Spines/metabolism , Hippocampus/metabolism , Neurons/physiology , Protein-Tyrosine Kinases/metabolism , Synapses/physiology , Memory
2.
J Thorac Oncol ; 16(4): 572-582, 2021 04.
Article in English | MEDLINE | ID: mdl-33309988

ABSTRACT

INTRODUCTION: Robust data on the outcome of MET-aberrant NSCLC with nontargeted therapies are limited, especially in consideration of the heterogeneity of MET-amplified tumors (METamp). METHODS: A total of 337 tumor specimens of patients with MET-altered Union for International Cancer Control stage IIIB/IV NSCLC were analyzed using next-generation sequencing, fluorescence in situ hybridization, and immunohistochemistry. The evaluation focused on the type of MET aberration, co-occurring mutations, programmed death-ligand 1 expression, and overall survival (OS). RESULTS: METamp tumors (n = 278) had a high frequency of co-occurring mutations (>80% for all amplification levels), whereas 57.6% of the 59 patients with MET gene and exon 14 (METex14) tumors had no additional mutations. In the METamp tumors, with increasing gene copy number (GCN), the frequency of inactivating TP53 mutations increased (GCN < 4: 58.2%; GCN ≥ 10: 76.5%), whereas the frequency of KRAS mutations decreased (GCN < 4: 43.2%; GCN ≥ 10: 11.8%). A total of 10.1% of all the METamp tumors with a GCN ≥ 10 had a significant worse OS (4.0 mo; 95% CI: 1.9-6.0) compared with the tumors with GCN < 10 (12.0 mo; 95% confidence interval [CI]: 9.4-14.6). In the METamp NSCLC, OS with immune checkpoint inhibitor (ICI) therapy was significantly better compared with chemotherapy with 19.0 months (95% CI: 15.8-22.2) versus 8.0 months (95% CI: 5.8-10.2, p < 0.0001). No significant difference in median OS was found between ICI therapy and chemotherapy in the patients with METex14 (p = 0.147). CONCLUSIONS: METex14, METamp GCN ≥ 10, and METamp GCN < 10 represent the subgroups of MET-dysregulated NSCLC with distinct molecular and clinical features. The patients with METex14 do not seem to benefit from immunotherapy in contrast to the patients with METamp, which is of particular relevance for the prognostically poor METamp GCN ≥ 10 subgroup.


Subject(s)
Lung Neoplasms , Genetic Heterogeneity , Humans , Immunotherapy , In Situ Hybridization, Fluorescence , Lung Neoplasms/drug therapy , Lung Neoplasms/genetics , Mutation , Proto-Oncogene Proteins c-met/genetics
3.
BMC Neurol ; 19(1): 345, 2019 Dec 29.
Article in English | MEDLINE | ID: mdl-31884946

ABSTRACT

BACKGROUND: Hyperprolinemia type 2 (HPII) is a rare autosomal recessive disorder of the proline metabolism, that affects the ALDH4A1 gene. So far only four different pathogenic mutations are known. The manifestation is mostly in neonatal age, in early infancy or early childhood. CASE PRESENTATION: The 64-years female patient had a long history of abdominal pain, and episode of an acute neuritis. Ten years later she was admitted into the neurological intensive-care-unit with acute abdominal pain, multiple generalized epileptic seizures, a vertical gaze palsy accompanied by extensive lactic acidosis in serum 26.0 mmol/l (reference: 0.55-2.2 mmol/l) and CSF 12.01 mmol/l (reference: 1.12-2.47 mmol/l). Due to repeated epileptic seizures and secondary complications a long-term sedation with a ventilation therapy over 20 days was administered. A diagnostic work-up revealed up to 400-times increased prolin-level in urine CSF and blood. Furthermore, a low vitamin-B6 serum value was found, consistent with a HPII causing secondary pyridoxine deficiency and seizures. The ALDH4A1 gene sequencing confirmed two previously unknown compound heterozygous variants (ALDH4A1 gene (NM_003748.3) Intron 1: c.62 + 1G > A - heterozygous and ALDH4A1 gene (NM_003748.3) Exon 5 c.349G > C, p.(Asp117His) - heterozygous). Under high-dose vitamin-B6 therapy no further seizures occurred. CONCLUSION: We describe two novel ALDH4A1-variants in an adult patient with hyperprolinemia type II causing secondary pyridoxine deficiency and seizures. Severe and potentially life-threatening course of this treatable disease emphasizes the importance of diagnostic vigilance and thorough laboratory work-up including gene analysis even in cases with atypical late manifestation.


Subject(s)
1-Pyrroline-5-Carboxylate Dehydrogenase/deficiency , Amino Acid Metabolism, Inborn Errors/genetics , 1-Pyrroline-5-Carboxylate Dehydrogenase/genetics , Acidosis, Lactic/etiology , Adult , Amino Acid Metabolism, Inborn Errors/complications , Female , Humans , Mutation , Status Epilepticus/etiology
4.
Front Cell Neurosci ; 13: 291, 2019.
Article in English | MEDLINE | ID: mdl-31316356

ABSTRACT

Neuronal activity is thought to drive the remodeling of circuits in the mammalian cerebral cortex. However, its precise function in the underlying formation and elimination of glutamatergic synapses has remained controversial. To clarify the role of activity in synapse turnover, we have assessed the effects of inhibition of glutamate release from a sparse subset of cultured hippocampal neurons on synapse turnover. Sustained chemogenetic attenuation of release through presynaptic expression of a designer receptor exclusively activated by designer drugs (DREADD) had no effect on the formation or elimination of glutamatergic synapses. Sparse expression of tetanus neurotoxin light chain (TeNT-LC), a synaptobrevin-cleaving protease that completely abolishes neurotransmitter release, likewise did not lead to changes in the rate of synapse elimination, although it reduced the rate of synapse formation. The stability of active and silenced synapses correlated with measures of synapse size. While not excluding a modulatory role in synapse elimination, our findings show that synaptic activity is neither required for the removal nor the maintenance of glutamatergic synapses between hippocampal neurons. Our results also demonstrate that the stability of glutamatergic synapses scales with their size irrespective of their activity.

5.
Clin Chem Lab Med ; 57(9): 1308-1318, 2019 08 27.
Article in English | MEDLINE | ID: mdl-30721141

ABSTRACT

Background Procalcitonin (PCT)-guided antibiotic stewardship (ABS) has been shown to reduce antibiotics (ABxs), with lower side-effects and an improvement in clinical outcomes. The aim of this experts workshop was to derive a PCT algorithm ABS for easier implementation into clinical routine across different clinical settings. Methods Clinical evidence and practical experience with PCT-guided ABS was analyzed and discussed, with a focus on optimal PCT use in the clinical context and increased adherence to PCT protocols. Using a Delphi process, the experts group reached consensus on different PCT algorithms based on clinical severity of the patient and probability of bacterial infection. Results The group agreed that there is strong evidence that PCT-guided ABS supports individual decisions on initiation and duration of ABx treatment in patients with acute respiratory infections and sepsis from any source, thereby reducing overall ABx exposure and associated side effects, and improving clinical outcomes. To simplify practical application, the expert group refined the established PCT algorithms by incorporating severity of illness and probability of bacterial infection and reducing the fixed cut-offs to only one for mild to moderate and one for severe disease (0.25 µg/L and 0.5 µg/L, respectively). Further, guidance on interpretation of PCT results to initiate, withhold or discontinue ABx treatment was included. Conclusions A combination of clinical patient assessment with PCT levels in well-defined ABS algorithms, in context with continuous education and regular feedback to all ABS stakeholders, has the potential to improve the diagnostic and therapeutic management of patients suspected of bacterial infection, thereby improving ABS effectiveness.


Subject(s)
Antimicrobial Stewardship/methods , Procalcitonin/metabolism , Adult , Algorithms , Anti-Bacterial Agents/therapeutic use , Bacterial Infections/diagnosis , Biomarkers/blood , Calcitonin/therapeutic use , Consensus , Female , Humans , Male , Middle Aged , Procalcitonin/physiology , Sepsis/diagnosis
6.
J Cell Biol ; 217(2): 715-730, 2018 02 05.
Article in English | MEDLINE | ID: mdl-29317530

ABSTRACT

The actin cytoskeleton is essential for the structural changes in dendritic spines that lead to the formation of new synapses. Although the molecular mechanisms underlying spine formation are well characterized, the events that drive spine maturation during development are largely unknown. In this study, we demonstrate that Angiomotin (AMOT-130) is necessary for spine stabilization. AMOT-130 is enriched in mature dendritic spines and functions to stabilize the actin cytoskeleton by coupling F-actin to postsynaptic protein scaffolds. These functions of AMOT are transiently restricted during postnatal development by phosphorylation imposed by the kinase Lats1. Our study proposes that AMOT-130 is essential for normal spine morphogenesis and identifies Lats1 as an upstream regulator in this process. Moreover, our findings may link AMOT-130 loss and the related spine defects to neurological disorders.


Subject(s)
Dendritic Spines/metabolism , Intercellular Signaling Peptides and Proteins/metabolism , Membrane Proteins/metabolism , Angiomotins , Animals , Cells, Cultured , Rats , Rats, Sprague-Dawley
7.
Sci Rep ; 7: 42920, 2017 02 21.
Article in English | MEDLINE | ID: mdl-28220838

ABSTRACT

Neurexins are a diverse family of cell adhesion molecules that localize to presynaptic specializations of CNS neurons. Heterologous expression of neurexins in non-neuronal cells leads to the recruitment of postsynaptic proteins in contacting dendrites of co-cultured neurons, implicating neurexins in synapse formation. However, isoform-specific knockouts of either all α- or all ß-neurexins show defects in synaptic transmission but an unaltered density of glutamatergic synapses, a finding that argues against an essential function of neurexins in synaptogenesis. To address the role of neurexin in synapse formation and function, we disrupted the function of all α- and ß-neurexins in cultured hippocampal neurons by shRNA knockdown or by overexpressing a neurexin mutant that is unable to bind to postsynaptic neurexin ligands. We show that neurexin perturbation results in an attenuation of neurotransmitter release that is in large part due to a reduction in the number of readily releasable synaptic vesicles. We also find that neurexin perturbation fails to alter the ability of neurons to form synapses, but rather leads to more frequent synapse elimination. These experiments suggest that neurexins are dispensable for the formation of initial synaptic contacts, but play an essential role in the stabilization and functional maturation of synapses.


Subject(s)
Glycoproteins/metabolism , Nerve Tissue Proteins/metabolism , Neuropeptides/metabolism , Synapses/metabolism , Animals , COS Cells , Cells, Cultured , Chlorocebus aethiops , Coculture Techniques , Glycoproteins/antagonists & inhibitors , Glycoproteins/genetics , Hippocampus/cytology , Hippocampus/metabolism , Membrane Proteins/metabolism , Nerve Tissue Proteins/antagonists & inhibitors , Nerve Tissue Proteins/genetics , Neural Cell Adhesion Molecules/metabolism , Neuropeptides/antagonists & inhibitors , Neuropeptides/genetics , Neurotransmitter Agents/metabolism , RNA Interference , RNA, Small Interfering/metabolism , Rats , Rats, Sprague-Dawley , Synaptic Vesicles/metabolism
8.
Biomed Eng Online ; 12: 7, 2013 Jan 28.
Article in English | MEDLINE | ID: mdl-23356939

ABSTRACT

BACKGROUND: Extracorporeal membrane oxygenation (ECMO) can replace the lungs' gas exchange capacity in refractory lung failure. However, its limited hemocompatibility, the activation of the coagulation and complement system as well as plasma leakage and protein deposition hamper mid- to long-term use and have constrained the development of an implantable lung assist device. In a tissue engineering approach, lining the blood contact surfaces of the ECMO device with endothelial cells might overcome these limitations. As a first step towards this aim, we hypothesized that coating the oxygenator's gas exchange membrane with proteins might positively influence the attachment and proliferation of arterial endothelial cells. METHODS: Sheets of polypropylene (PP), polyoxymethylpentene (TPX) and polydimethylsiloxane (PDMS), typical material used for oxygenator gas exchange membranes, were coated with collagen, fibrinogen, gelatin or fibronectin. Tissue culture treated well plates served as controls. Endothelial cell attachment and proliferation were analyzed for a period of 4 days by microscopic examination and computer assisted cell counting. RESULTS: Endothelial cell seeding efficiency is within range of tissue culture treated controls for fibronectin treated surfaces only. Uncoated membranes as well as all other coatings lead to lower cell attachment. A confluent endothelial cell layer develops on fibronectin coated PDMS and the control surface only. CONCLUSIONS: Fibronectin increases endothelial cells' seeding efficiency on different oxygenator membrane material. PDMS coated with fibronectin shows sustained cell attachment for a period of four days in static culture conditions.


Subject(s)
Endothelial Cells/cytology , Fibronectins/chemistry , Oxygenators, Membrane , Animals , Biocompatible Materials , Cell Adhesion , Collagen/chemistry , Dimethylpolysiloxanes/chemistry , Endothelium, Vascular/cytology , Extracorporeal Membrane Oxygenation/methods , Fibrinogen/chemistry , Gelatin/chemistry , Polypropylenes/chemistry , Sheep , Tissue Culture Techniques , Tissue Engineering/methods
9.
Sensors (Basel) ; 13(1): 898-917, 2013 Jan 14.
Article in English | MEDLINE | ID: mdl-23344383

ABSTRACT

Body sensor networks (BSN) are an important research topic due to various advantages over conventional measurement equipment. One main advantage is the feasibility to deploy a BSN system for 24/7 health monitoring applications. The requirements for such an application are miniaturization of the network nodes and the use of wireless data transmission technologies to ensure wearability and ease of use. Therefore, the reliability of such a system depends on the quality of the wireless data transmission. At present, most BSNs use ZigBee or other IEEE 802.15.4 based transmission technologies. Here, we evaluated the performance of a wireless transmission system of a novel BSN for biomedical applications in the 433MHz ISM band, called Integrated Posture and Activity NEtwork by Medit Aachen (IPANEMA) BSN. The 433MHz ISM band is used mostly by implanted sensors and thus allows easy integration of such into the BSN. Multiple measurement scenarios have been assessed, including varying antenna orientations, transmission distances and the number of network participants. The mean packet loss rate (PLR) was 0.63% for a single slave, which is comparable to IEEE 802.15.4 BSNs in the proximity of Bluetooth or WiFi networks. Secondly, an enhanced version is evaluated during on-body measurements with five slaves. The mean PLR results show a comparable good performance for measurements on a treadmill (2.5%), an outdoor track (3.4%) and in a climate chamber (1.5%).


Subject(s)
Biomedical Technology/instrumentation , Biomedical Technology/methods , Monitoring, Ambulatory/instrumentation , Computer Communication Networks/instrumentation , Humans , Signal Processing, Computer-Assisted , Spectrum Analysis , Time Factors
10.
Urol Int ; 86(4): 393-8, 2011.
Article in English | MEDLINE | ID: mdl-21335950

ABSTRACT

OBJECTIVES: Endorectal coil MRI (endoMRI) of the prostate is useful to evaluate tumor localization. There is little evidence on patient characteristics affecting its diagnostic performance. We evaluate the influence of clinical and histological parameters on the accuracy of endoMRI. METHODS: Sixty-nine patients with prostate cancer were included. After virtually dividing the prostate into pixels of 1 cm2, results of endoMRI were compared with those from prostatectomy specimens' whole-mount sections. Univariate and multivariate analyses were performed to calculate the impact of clinical and histological parameters on the number of appropriately described pixels. RESULTS: In 9, no tumor could be demonstrated by endoMRI. 48.3% of patients were staged correctly, 23.3% were over- and 28.3% understaged. Mean rates of correctly labeled pixels were 0.44 (± 0.04 SEM) for tumor and 0.90 (± 0.01) for benign segments. In univariate analysis, the rate of correctly labeled tumor segments showed significant positive correlations with Gleason score ≥7 and negative correlations with prostate weight and multifocality. The rate of correctly labeled benign segments showed significant negative correlation with tumor weight. All factors were independent variables in multivariate analysis. CONCLUSIONS: The reliability of endoMRI depends on clinical parameters. Higher Gleason scores, unifocal tumors and smaller prostate volumes ameliorate endoMRI performance.


Subject(s)
Magnetic Resonance Imaging/methods , Prostatic Neoplasms/pathology , Aged , Humans , Male , Medical Oncology/methods , Middle Aged , Neoplasm Staging/methods , Organ Size , Prostate/pathology , Prostate-Specific Antigen/biosynthesis , Prostatectomy/methods , Prostatic Neoplasms/diagnosis
11.
Hum Mutat ; 32(4): 424-35, 2011 Apr.
Article in English | MEDLINE | ID: mdl-21309039

ABSTRACT

The effects of missense changes and small in-frame deletions and insertions on protein function are not easy to predict, and the identification of such variants in individuals at risk of a genetic disease can complicate genetic counselling. One option is to perform functional tests to assess whether the variants affect protein function. We have used this strategy to characterize variants identified in the TSC1 and TSC2 genes in individuals with, or suspected of having, Tuberous Sclerosis Complex (TSC). Here we present an overview of our functional studies on 45 TSC1 and 107 TSC2 variants. Using a standardized protocol we classified 16 TSC1 variants and 70 TSC2 variants as pathogenic. In addition we identified eight putative splice site mutations (five TSC1 and three TSC2). The remaining 24 TSC1 and 34 TSC2 variants were classified as probably neutral.


Subject(s)
Genetic Variation , Tuberous Sclerosis/genetics , Tumor Suppressor Proteins/genetics , Cells, Cultured , Humans , Models, Genetic , Tuberous Sclerosis/metabolism , Tuberous Sclerosis Complex 1 Protein , Tuberous Sclerosis Complex 2 Protein
12.
J Neurochem ; 114(1): 311-22, 2010 Jul.
Article in English | MEDLINE | ID: mdl-20456004

ABSTRACT

Imbalances in brain cholesterol homeostasis have been observed in several neurodegenerative diseases. In Niemann-Pick Type C (NPC) disease, mutations in NPC1 or NPC2 lead to endosomal cholesterol accumulation, neuronal dysfunction and death. Cholesterol in synaptic plasma membranes influences membrane fluidity, curvature, and protein function, and its depletion may adversely affect synaptic vesicle cycling. We have investigated pre-synaptic function in primary hippocampal neurons with altered cholesterol distribution because of NPC1 deficiency or cyclodextrin treatment. In NPC1-deficient neurons grown in serum-free medium, plasma membrane cholesterol was reduced and total synaptic vesicle release during prolonged stimulation was attenuated. In NPC1-deficient neurons cultured in the presence of high-density lipoproteins, plasma membrane cholesterol markedly increased, but the defects in synaptic vesicle release in NPC1-deficient neurons were exacerbated. Treatment with 1 mM methyl-beta-cyclodextrin acutely depleted plasma membrane cholesterol in wild-type neurons to levels below those in NPC1 deficiency, but did not alter synaptic vesicle exo- or endocytosis. Defects only became apparent when higher methyl-beta-cyclodextrin concentrations were used. Our data indicate that synaptic vesicle release can tolerate some degree of plasma membrane cholesterol depletion and suggest that the pre-synaptic defects in NPC1-deficient neurons are not solely caused by a reduction of plasma membrane cholesterol.


Subject(s)
Cell Membrane/metabolism , Cholesterol/metabolism , Hippocampus/metabolism , Neurons/metabolism , Proteins/genetics , Animals , Cyclodextrins/pharmacology , Endocytosis , Endosomes/metabolism , Exocytosis , Fluorescent Dyes , Genes, Reporter , Intracellular Signaling Peptides and Proteins , Lipoproteins, HDL/pharmacology , Mice , Mice, Knockout , Niemann-Pick C1 Protein , Proteins/physiology , Pyridinium Compounds , Quaternary Ammonium Compounds , Synaptic Vesicles/metabolism
13.
J Clin Oncol ; 28(16): 2712-8, 2010 Jun 01.
Article in English | MEDLINE | ID: mdl-20439646

ABSTRACT

PURPOSE: Invasion and migration are key processes of glioblastoma and are tightly linked to tumor recurrence. Integrin inhibition using cilengitide has shown synergy with chemotherapy and radiotherapy in vitro and promising activity in recurrent glioblastoma. This multicenter, phase I/IIa study investigated the efficacy and safety of cilengitide in combination with standard chemoradiotherapy in newly diagnosed glioblastoma. PATIENTS AND METHODS: Patients (age > or = 18 to < or = 70 years) were treated with cilengitide (500 mg) administered twice weekly intravenously in addition to standard radiotherapy with concomitant and adjuvant temozolomide. Treatment was continued until disease progression or for up to 35 weeks. The primary end point was progression-free survival (PFS) at 6 months. RESULTS: Fifty-two patients (median age, 57 years; 62% male) were included. Six- and 12-month PFS rates were 69% (95% CI, 54% to 80%) and 33% (95% CI, 21% to 46%). Median PFS was 8 months (95% CI, 6.0 to 10.7 months). Twelve- and 24-month overall survival (OS) rates were 68% (95% CI, 53% to 79%) and 35% (95% CI, 22% to 48%). Median OS was 16.1 months (95% CI, 13.1 to 23.2 months). PFS and OS were longer in patients with tumors with O(6)-methylguanine-DNA methyltransferase (MGMT) promoter methylation (13.4 and 23.2 months) versus those without MGMT promoter methylation (3.4 and 13.1 months). The combination of cilengitide with temozolomide and radiotherapy was well tolerated, with no additional toxicity. No pharmacokinetic interactions between temozolomide and cilengitide were identified. CONCLUSION: Compared with historical controls, the addition of concomitant and adjuvant cilengitide to standard chemoradiotherapy demonstrated promising activity in patients with glioblastoma with MGMT promoter methylation.


Subject(s)
Brain Neoplasms/mortality , Brain Neoplasms/therapy , Dacarbazine/analogs & derivatives , Glioblastoma/mortality , Glioblastoma/therapy , Snake Venoms/administration & dosage , Adult , Aged , Antineoplastic Agents, Alkylating/administration & dosage , Antineoplastic Agents, Alkylating/adverse effects , Biopsy, Needle , Brain Neoplasms/pathology , Combined Modality Therapy , Confidence Intervals , Dacarbazine/administration & dosage , Dacarbazine/adverse effects , Disease-Free Survival , Dose-Response Relationship, Drug , Drug Administration Schedule , Female , Follow-Up Studies , Glioblastoma/pathology , Humans , Immunohistochemistry , Infusions, Intravenous , Kaplan-Meier Estimate , Male , Maximum Tolerated Dose , Middle Aged , Neoplasm Recurrence, Local/mortality , Neoplasm Recurrence, Local/pathology , Neoplasm Staging , Neurosurgical Procedures/methods , Probability , Radiotherapy, Adjuvant , Radiotherapy, Conformal , Risk Assessment , Snake Venoms/adverse effects , Survival Analysis , Temozolomide , Treatment Outcome
14.
Proc Natl Acad Sci U S A ; 107(19): 8836-41, 2010 May 11.
Article in English | MEDLINE | ID: mdl-20421490

ABSTRACT

The likelihood with which an action potential elicits neurotransmitter release, the release probability (p(r)), is an important component of synaptic strength. Regulatory mechanisms controlling several steps of synaptic vesicle (SV) exocytosis may affect p(r), yet their relative importance in determining p(r) and eliciting temporal changes in neurotransmitter release at individual synapses is largely unknown. We have investigated whether the size of the active zone cytomatrix is a major determinant of p(r) and whether changes in its size lead to corresponding alterations in neurotransmitter release. We have used a fluorescent sensor of SV exocytosis, synaptophysin-pHluorin, to measure p(r) at individual synapses with high accuracy and employed a fluorescently labeled cytomatrix protein, Bassoon, to quantify the amount of active zone cytomatrix present at these synapses. We find that, for synapses made by a visually identified presynaptic neuron, p(r) is indeed strongly correlated with the amount of active zone cytomatrix present at the presynaptic specialization. Intriguingly, active zone cytomatrices are frequently subject to synapse-specific changes in size on a time scale of minutes. These spontaneous alterations in active zone size are associated with corresponding changes in neurotransmitter release. Our results suggest that the size of the active zone cytomatrix has a large influence on the reliability of synaptic transmission. Furthermore, they implicate mechanisms leading to rapid structural alterations at active zones in synapse-specific forms of plasticity.


Subject(s)
Neurotransmitter Agents/metabolism , Synaptic Vesicles/chemistry , Synaptic Vesicles/metabolism , Animals , Biosensing Techniques , Exocytosis , Green Fluorescent Proteins/metabolism , Hippocampus/metabolism , Neuronal Plasticity , Probability , Rats , Synaptophysin/metabolism , Time Factors
15.
J Neurosci ; 30(13): 4796-805, 2010 Mar 31.
Article in English | MEDLINE | ID: mdl-20357130

ABSTRACT

The formation and function of the neuronal synapse is dependent on the asymmetric distribution of proteins both presynaptically and postsynaptically. Recently, proteins important in establishing cellular polarity have been implicated in the synapse. We therefore performed a proteomic screen with known polarity proteins and identified novel complexes involved in synaptic function. Specifically, we show that the tumor suppressor protein, Scribble, associates with neuronal nitric oxide synthase (nNOS) adaptor protein (NOS1AP) [also known as C-terminal PDZ ligand of nNOS (CAPON)] and is found both presynaptically and postsynaptically. The Scribble-NOS1AP association is direct and is mediated through the phosphotyrosine-binding (PTB) domain of NOS1AP and the fourth PDZ domain of Scribble. Further, we show that Scribble bridges NOS1AP to a beta-Pix [beta-p21-activated kinase (PAK)-interacting exchange factor]/Git1 (G-protein-coupled receptor kinase-interacting protein)/PAK complex. The overexpression of NOS1AP leads to an increase in dendritic protrusions, in a fashion that depends on the NOS1AP PTB domain. Consistent with these observations, both full-length NOS1AP and the NOS1AP PTB domain influence Rac activity. Together these data suggest that NOS1AP plays an important role in the mammalian synapse.


Subject(s)
Adaptor Proteins, Signal Transducing/metabolism , Dendritic Spines/physiology , Tumor Suppressor Proteins/metabolism , Amino Acid Sequence , Animals , Binding Sites , Cell Cycle Proteins/metabolism , Cell Line , Guanine Nucleotide Exchange Factors/metabolism , Humans , Molecular Sequence Data , Multiprotein Complexes , Phosphotyrosine/metabolism , Protein Isoforms/metabolism , Protein Structure, Tertiary , Rats , Rho Guanine Nucleotide Exchange Factors , p21-Activated Kinases/metabolism , rac GTP-Binding Proteins/metabolism
16.
Dermatol Online J ; 15(10): 4, 2009 Oct 15.
Article in English | MEDLINE | ID: mdl-19951622

ABSTRACT

Basal cell carcinoma (BCC), the most common cutaneous malignant tumor, may display neuroendocrine differentiation in very rare instances. We here describe a case of a BCC with neuroendocrine differentiation that arose in a scar resulting from a trauma 75 years earlier. Neuroendocrine differentiation was proven by immunohistochemistry and electron microscopy. The simultaneous occurrence of BCC development in a scar and neuroendocrine differentiation is quite rare.


Subject(s)
Carcinoma, Basal Cell/complications , Cicatrix/complications , Skin Neoplasms/complications , Aged , Carcinoma, Basal Cell/pathology , Female , Humans , Skin Neoplasms/pathology
17.
Int J Colorectal Dis ; 22(2): 137-43, 2007 Feb.
Article in English | MEDLINE | ID: mdl-16896994

ABSTRACT

INTRODUCTION: N-Acetyltransferase (NAT) 2 is an important enzyme involved in the metabolism of different xenobiotics, including potential carcinogens. Allelic variants of the NAT2 gene are determined by a pattern of single nucleotide polymorphisms (SNPs) resulting in slow (SA), intermediate (IA) or rapid acetylator (RA) phenotypes and causing the individual differences in the NAT2 metabolic capacity. To clarify the potential modifying role of the NAT2 acetylator status in microsatellite stable (MSS) colorectal cancer (CRC), we studied 140 patients with sporadic CRC (group 1) and 69 patients with CRC who met at least one criterion of the revised Bethesda guidelines (group 2). OBSERVATIONS: We did not observe any significant difference in the NAT2 acetylator status frequency between patients in both groups and 100 healthy controls (P=0.486). Regardless of a younger median age of tumour onset (AO) of 41 years in group 2 patients compared to 64 years in group 1 patients, no significant difference in AO was found between RA and SA status patients in both groups. The median AO in group 1 was 65 years in patients with RA and 63 years with SA status (P=0.065). The median AO in group 2 was 40 years in patients with RA and 42 years with SA status (P=0.814). Multivariate Cox regression analysis revealed that neither the NAT2 acetylator status (P=0.064 and 0.810, respectively) nor the gender (P=0.165 and 0.918, respectively) was a risk factor for the AO in both groups. These data do not support the hypothesis that the NAT2 acetylatorship acts as a modifying factor on the AO in sporadic and familial, microsatellite stable CRC.


Subject(s)
Arylamine N-Acetyltransferase/genetics , Colorectal Neoplasms/genetics , Acetylation , Adult , Age of Onset , Aged , Female , Humans , Male , Microsatellite Instability , Middle Aged , Polymorphism, Single Nucleotide
18.
Physiology (Bethesda) ; 21: 346-51, 2006 Oct.
Article in English | MEDLINE | ID: mdl-16990455

ABSTRACT

The cellular mechanisms contributing to long-term potentiation and activity-induced formation of glutamatergic synapses have been intensely debated. Recent studies have sparked renewed interest in the role of presynaptic components in these processes. Based on the present evidence, it appears likely that long-term plasticity utilizes both pre- and postsynaptic expression mechanisms.


Subject(s)
Neuronal Plasticity , Presynaptic Terminals/physiology , Action Potentials , Animals , Glutamic Acid/metabolism , Glutamic Acid/physiology , Humans , Neurotransmitter Agents/metabolism , Neurotransmitter Agents/physiology , Synapses/physiology
19.
J Neurosci Methods ; 152(1-2): 32-9, 2006 Apr 15.
Article in English | MEDLINE | ID: mdl-16198002

ABSTRACT

The use of fluorescent probes such as FM 1-43 or synapto-pHluorin to study the dynamic aspects of synaptic function has dramatically increased in recent years. The analysis of such experiments is both labor intensive and subject to potentially significant experimenter bias. For our analysis of fluorescently labeled synapses in cultured hippocampal neurons, we have developed an automated approach to punctum identification and classification. This automatic selection and processing of fluorescently labeled synaptic puncta not only reduces the chance of subjective bias and improves the quality and reproducibility of the analyses, but also greatly increases the number of release sites that can be rapidly analyzed from a given experiment, increasing the signal-to-noise ratio of the data. An important innovation to the automation of analysis is our method for objectively selecting puncta for analysis, particularly important for studying and comparing dynamic functional properties of a large population of individual synapses. The fluorescence change for each individual punctum is automatically scored according to several criteria, allowing objective assessment of the quality of each site. An entirely automated and thus unbiased analysis of fluorescence in the study of synaptic function is critical to providing a comprehensive understanding of the cellular and molecular underpinnings of neurotransmission and plasticity.


Subject(s)
Image Processing, Computer-Assisted/methods , Synapses/physiology , Animals , Cells, Cultured , Data Interpretation, Statistical , Fluorescent Dyes , Hippocampus/cytology , Hippocampus/metabolism , Mice , Microscopy, Fluorescence , Neuronal Plasticity/physiology , Neurons/metabolism , Software , Synaptic Transmission/physiology
20.
Arch Gynecol Obstet ; 273(5): 312-4, 2006 Feb.
Article in English | MEDLINE | ID: mdl-16328396

ABSTRACT

BACKGROUND: Epidermal cyst of the breast is a rare benign intramammary lesion; however, a common finding in other parts of the body and most often located in the scalp, back, and neck. Only a few cases of epidermal cysts of the breast have been reported in literature. CASE REPORT: The patient presented with a small movable left breast lump. Mammography and ultrasonography did not show features of a benign lesion. Ultrasound-guided core biopsy was undertaken. Histology showed an epidermal cyst. The patient returned with an inflammation at the puncture site and a small abscess seen on ultrasound. The abscess was removed surgically. CONCLUSION: Mammographic and sonographic features of an epidermal cyst may mimick a malignant lesion. Biopsy can result in complications, such as inflammation. In addition, an association between epidermal cyst and squamous carcinoma has been reported. Therefore, it is recommended that these lesions are resected.


Subject(s)
Breast Neoplasms , Epidermal Cyst/diagnostic imaging , Epidermal Cyst/pathology , Biopsy , Diagnosis, Differential , Female , Humans , Mammography , Middle Aged , Ultrasonography
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