Publications by authors named "Michael Lanz"

30 Publications

  • Page 1 of 1

Checkpoint-mediated DNA polymerase ε exonuclease activity curbing counteracts resection-driven fork collapse.

Mol Cell 2021 Apr 22. Epub 2021 Apr 22.

Center for Biological Research Margarita Salas (CIB-CSIC), Spanish National Research Council, Madrid, Spain. Electronic address:

DNA polymerase ε (Polε) carries out high-fidelity leading strand synthesis owing to its exonuclease activity. Polε polymerase and exonuclease activities are balanced, because of partitioning of nascent DNA strands between catalytic sites, so that net resection occurs when synthesis is impaired. In vivo, DNA synthesis stalling activates replication checkpoint kinases, which act to preserve the functional integrity of replication forks. We show that stalled Polε drives nascent strand resection causing fork functional collapse, averted via checkpoint-dependent phosphorylation. Polε catalytic subunit Pol2 is phosphorylated on serine 430, influencing partitioning between polymerase and exonuclease active sites. A phosphormimetic S430D change reduces exonucleolysis in vitro and counteracts fork collapse. Conversely, non-phosphorylatable pol2-S430A expression causes resection-driven stressed fork defects. Our findings reveal that checkpoint kinases switch Polε to an exonuclease-safe mode preventing nascent strand resection and stabilizing stalled replication forks. Elective partitioning suppression has implications for the diverse Polε roles in genome integrity maintenance.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.molcel.2021.04.006DOI Listing
April 2021

Resective epilepsy surgery in patients aged 50years and older - a retrospective study regarding seizure outcome, memory performance, and psychopathology.

Epilepsy Behav 2021 May 8;118:107933. Epub 2021 Apr 8.

Protestant Hospital Alsterdorf, Epilepsy Center Hamburg, Elisabeth-Flügge-Str. 1, 22337 Hamburg, Germany. Electronic address:

Purpose: To assess clinical and demographic characteristics in two cohorts of elderly patients with drug-resistant focal epilepsy, undergoing resective epilepsy surgery (RES). Further, to determine seizure, neuropsychological, and mental health outcomes after RES and evaluate possible influencing factors.

Methods: Consecutive patients aged ≥50 years with temporal lobe epilepsy (TLE) who underwent curative RES in the Hamburg epilepsy surgery program (2004-2017) were identified. Data were retrospectively analyzed. Seizure outcome was classified according to ILAE and Engel outcome scales in patients with first-time surgeries and with reoperations. Previously reported predictors of the seizure outcome were evaluated using regression analyses. Changes in verbal memory were assessed for patients with complete pre- and postoperative datasets (n=30) using repeated-measures analysis of variance. For evaluation of possible predictors of psychopathologic changes after RES a regression analysis was conducted.

Results: Fifty-one elderly patients underwent RES of the temporal lobe, including twelve aged ≥60 years, and five with reoperations. After one year, 65% of the patients with first-time surgeries were seizure free and 91% had a favorable outcome. At last follow-up, 49% were seizure free since surgery. Three reoperated patients had an Engel I outcome. Seizure outcome was not dependent on age at surgery, duration of epilepsy, or other evaluated variables. There was no significant decline in the memory performance after surgery. Significant improvements in mental health were found.

Conclusion: RES for drug-resistant TLE is safe, effective, and improves mental health also in patients aged ≥ 50 years. Thus, it should be evaluated as the treatment of choice also in this age group.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.yebeh.2021.107933DOI Listing
May 2021

In-depth and 3-dimensional exploration of the budding yeast phosphoproteome.

EMBO Rep 2021 Feb 25;22(2):e51121. Epub 2021 Jan 25.

Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY, USA.

Phosphorylation is one of the most dynamic and widespread post-translational modifications regulating virtually every aspect of eukaryotic cell biology. Here, we assemble a dataset from 75 independent phosphoproteomic experiments performed in our laboratory using Saccharomyces cerevisiae. We report 30,902 phosphosites identified from cells cultured in a range of DNA damage conditions and/or arrested in distinct cell cycle stages. To generate a comprehensive resource for the budding yeast community, we aggregate our dataset with the Saccharomyces Genome Database and another recently published study, resulting in over 46,000 budding yeast phosphosites. With the goal of enhancing the identification of functional phosphorylation events, we perform computational positioning of phosphorylation sites on available 3D protein structures and systematically identify events predicted to regulate protein complex architecture. Results reveal hundreds of phosphorylation sites mapping to or near protein interaction interfaces, many of which result in steric or electrostatic "clashes" predicted to disrupt the interaction. With the advancement of Cryo-EM and the increasing number of available structures, our approach should help drive the functional and spatial exploration of the phosphoproteome.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.15252/embr.202051121DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7857435PMC
February 2021

The Rad53-Spt21 and Tel1 axes couple glucose tolerance to histone dosage and subtelomeric silencing.

Nat Commun 2020 08 19;11(1):4154. Epub 2020 Aug 19.

The FIRC Institute of Molecular Oncology (IFOM), Via Adamello 16, 20139, Milan, Italy.

The DNA damage response (DDR) coordinates DNA metabolism with nuclear and non-nuclear processes. The DDR kinase Rad53 controls histone degradation to assist DNA repair. However, Rad53 deficiency causes histone-dependent growth defects in the absence of DNA damage, pointing out unknown physiological functions of the Rad53-histone axis. Here we show that histone dosage control by Rad53 ensures metabolic homeostasis. Under physiological conditions, Rad53 regulates histone levels through inhibitory phosphorylation of the transcription factor Spt21 on Ser276. Rad53-Spt21 mutants display severe glucose dependence, caused by excess histones through two separable mechanisms: dampening of acetyl-coenzyme A-dependent carbon metabolism through histone hyper-acetylation, and Sirtuin-mediated silencing of starvation-induced subtelomeric domains. We further demonstrate that repression of subtelomere silencing by physiological Tel1 and Rpd3 activities coveys tolerance to glucose restriction. Our findings identify DDR mutations, histone imbalances and aberrant subtelomeric chromatin as interconnected causes of glucose dependence, implying that DDR kinases coordinate metabolism and epigenetic changes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41467-020-17961-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7438486PMC
August 2020

Characterization of an anti-FLAG antibody binding protein in V. cholerae.

Biochem Biophys Res Commun 2020 07 3;528(3):493-498. Epub 2020 Jun 3.

Weill Institute for Cell and Molecular Biology, Cornell, University, Ithaca, NY, 14853, USA; Department of Microbiology, Cornell University, Ithaca, NY, 14853, USA; Cornell Institute of Host-Microbe Interactions and Disease, Cornell University, Ithaca, NY, 14853, USA. Electronic address:

FLAG-tags are commonly used for protein abundance measurements and for identification of protein-protein interactions in living cells. We have observed that the cholera pathogen Vibrio cholerae encodes a FLAG-antibody-reactive protein and identified this protein as an outer membrane porin, Porin4, which contains a sequence very similar to the 3xFLAG epitope tag. We have demonstrated the binding affinity of the conserved peptide sequence (called Porin 4 tag) in Porin4 against monoclonal anti-FLAG M2 antibody. In addition, we created a porin4 deletion mutant, which can be used for background-less FLAG antibody detection experiments.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.bbrc.2020.05.169DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7357423PMC
July 2020

MaXLinker: Proteome-wide Cross-link Identifications with High Specificity and Sensitivity.

Mol Cell Proteomics 2020 03 15;19(3):554-568. Epub 2019 Dec 15.

Department of Computational Biology, Cornell University, Ithaca, New York,14853; Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, New York, 14853. Electronic address:

Protein-protein interactions play a vital role in nearly all cellular functions. Hence, understanding their interaction patterns and three-dimensional structural conformations can provide crucial insights about various biological processes and underlying molecular mechanisms for many disease phenotypes. Cross-linking mass spectrometry (XL-MS) has the unique capability to detect protein-protein interactions at a large scale along with spatial constraints between interaction partners. The inception of MS-cleavable cross-linkers enabled the MS2-MS3 XL-MS acquisition strategy that provides cross-link information from both MS2 and MS3 level. However, the current cross-link search algorithm available for MS2-MS3 strategy follows a "MS2-centric" approach and suffers from a high rate of mis-identified cross-links. We demonstrate the problem using two new quality assessment metrics ["fraction of mis-identifications" (FMI) and "fraction of interprotein cross-links from known interactions" (FKI)]. We then address this problem, by designing a novel "MS3-centric" approach for cross-link identification and implementing it as a search engine named MaXLinker. MaXLinker outperforms the currently popular search engine with a lower mis-identification rate, and higher sensitivity and specificity. Moreover, we performed human proteome-wide cross-linking mass spectrometry using K562 cells. Employing MaXLinker, we identified a comprehensive set of 9319 unique cross-links at 1% false discovery rate, comprising 8051 intraprotein and 1268 interprotein cross-links. Finally, we experimentally validated the quality of a large number of novel interactions identified in our study, providing a conclusive evidence for MaXLinker's robust performance.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1074/mcp.TIR119.001847DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7050104PMC
March 2020

Use of the mixed reality tool "VSI Patient Education" for more comprehensible and imaginable patient educations before epilepsy surgery and stereotactic implantation of DBS or stereo-EEG electrodes.

Epilepsy Res 2020 01 26;159:106247. Epub 2019 Nov 26.

Hamburg Epilepsy Center, Protestant Hospital Alsterdorf, Department of Neurology and Epileptology, Hamburg, Germany.

Purpose: It is unknown which patient education strategy before epilepsy surgery or stereotactic electrode implantation is best for patients. This prospective and randomized clinical study investigates whether the use of the mixed reality tool "VSI Patient Education" (VSI PE) running on HoloLens® glasses is superior to the use of a rubber brain model as a 3-dimensional tool for patient education before epilepsy surgery and stereotactic electrode implantation.

Material And Methods: 17 patients with indication for epilepsy surgery or stereotactic electrode implantation were included in the study and randomized into two groups. All patients were informed with both comparative tools VSI PE (apoQlar®) and a rubber brain model (3B Scientific®) in a chronological order depending on group assignment. Afterwards, the patient and, if present, a relative (12) each filled out a questionnaire. For statistical analysis, Wilcoxon rank-sum tests were performed.

Results: Patients found their patient education highly significantly more comprehensible (p = 0.001**, r = 0.84) and almost significantly more imaginable (p=0.020, r = 0.57), when their doctor used VSI PE compared to the rubber brain model. The patients felt significantly less anxious as a result of VSI PE (p = 0.008*, r = 0.64). Highly significantly more patients chose VSI PE as the preferred patient education tool (p < 0.001**, r = 0.91), and almost significantly more patients decided VSI PE to be the future standard tool (p = 0.020, r = 0.56). Significantly more relatives chose VSI PE as the preferred patient education tool (p = 0.004*, r = 0.83), and significantly more relatives decided VSI PE to be the future standard tool (p = 0.002*, r = 0.91).

Conclusion: VSI Patient Education is a promising new mixed reality tool for informing patients before epileptic surgery or stereotactic electrode implantation in order to enhance comprehension and imagination and reduce fear and worries. It might strengthen patient commitment and have a positive influence on patients' decisions in favor of medically indicated surgical operations.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.eplepsyres.2019.106247DOI Listing
January 2020

Deubiquitination of phosphoribosyl-ubiquitin conjugates by phosphodiesterase-domain-containing effectors.

Proc Natl Acad Sci U S A 2019 11 5;116(47):23518-23526. Epub 2019 Nov 5.

Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853;

Posttranslational protein modification by ubiquitin (Ub) is a central eukaryotic mechanism that regulates a plethora of physiological processes. Recent studies unveiled an unconventional type of ubiquitination mediated by the SidE family of effectors, such as SdeA, that catalyzes the conjugation of Ub to a serine residue of target proteins via a phosphoribosyl linker (hence named PR-ubiquitination). Comparable to the deubiquitinases in the canonical ubiquitination pathway, here we show that 2 paralogous effectors, Lpg2154 (DupA; deubiquitinase for PR-ubiquitination) and Lpg2509 (DupB), reverse PR-ubiquitination by specific removal of phosphoribosyl-Ub from substrates. Both DupA and DupB are fully capable of rescuing the Golgi fragmentation phenotype caused by exogenous expression of SdeA in mammalian cells. We further show that deletion of these 2 genes results in significant accumulation of PR-ubiquitinated species in host cells infected with In addition, we have identified a list of specific PR-ubiquitinated host targets and show that DupA and DupB play a role in modulating the association of PR-ubiquitinated host targets with -containing vacuoles. Together, our data establish a complete PR-ubiquitination and deubiquitination cycle and demonstrate the intricate control that has over this unusual Ub-dependent posttranslational modification.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1073/pnas.1916287116DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6876201PMC
November 2019

Can commercially available wearable EEG devices be used for diagnostic purposes? An explorative pilot study.

Epilepsy Behav 2020 02 20;103(Pt A):106507. Epub 2019 Oct 20.

Technical University of Munich, Department of Informatics, Boltzmannstraße 3, 85748 Garching, Germany. Electronic address:

Electroencephalography (EEG) is a core element in the diagnosis of epilepsy syndromes and can help to monitor antiseizure treatment. Mobile EEG (mEEG) devices are increasingly available on the consumer market and may offer easier access to EEG recordings especially in rural or resource-poor areas. The usefulness of consumer-grade devices for clinical purposes is still underinvestigated. Here, we compared EEG traces of a commercially available mEEG device (Emotiv EPOC) to a simultaneously recorded clinical video EEG (vEEG). Twenty-two adult patients (11 female, mean age 40.2 years) undergoing noninvasive vEEG monitoring for clinical purposes were prospectively enrolled. The EEG recordings were evaluated by 10 independent raters with unmodifiable view settings. The individual evaluations were compared with respect to the presence of abnormal EEG findings (regional slowing, epileptiform potentials, seizure pattern). Video EEG yielded a sensitivity of 56% and specificity of 88% for abnormal EEG findings, whereas mEEG reached 39% and 85%, respectively. Interrater reliability coefficients were better in vEEG as compared to mEEG (ϰ = 0.50 vs. 0.30), corresponding to a moderate and fair agreement. Intrarater reliability between mEEG and vEEG evaluations of simultaneous recordings of a given participant was moderate (ϰ = 0.48). Given the limitations of our exploratory pilot study, our results suggest that vEEG is superior to mEEG, but that mEEG can be helpful for diagnostic purposes. We present the first quantitative comparison of simultaneously acquired clinical and mobile consumer-grade EEG for a clinical use-case.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.yebeh.2019.106507DOI Listing
February 2020

Decision-making in temporal lobe epilepsy surgery based on invasive stereo-electroencephalography (sEEG).

Neurosurg Rev 2020 Oct 9;43(5):1403-1408. Epub 2019 Sep 9.

Department of Neurosurgery, University Medical Center Hamburg-Eppendorf, Martinistraße 52, 20246, Hamburg, Germany.

In medical refractory temporal lobe epilepsy (TLE), the epileptogenic zone can be difficult to identify and therefore difficult to treat, especially in the absence of clear MRI pathologies and specific results from presurgical evaluation. Invasive monitoring with stereo-electroencephalography (sEEG) is a tool for a better determination of the epileptogenic zone. Here, we investigate the impact of sEEG on decision-making in temporal lobe epilepsy surgery. We reviewed patients with TLE who underwent further investigation with sEEG in our epilepsy unit. We examined specifically how sEEG findings influenced our decision regarding indication for a surgical procedure and resection volume. From 2013 to 2017, we performed 152 temporal resections in epilepsy patients. Twenty-one of these patients were designated for further preoperative investigation with sEEG due to incongruent findings in presurgical evaluation. Six patients were implanted bitemporally. In five cases, the hypothesis for the epileptogenic zone and localization had to be changed due to sEEG findings and resulted in a different tailored resection than intended. In three cases, sEEG findings led to the cancelation of the originally intended temporal resection as the epileptogenic zone was not definable or bilateral. In another three cases, the prognosis for reduction of seizures postoperatively had to be reduced due to the sEEG findings. However, the resection was performed after interdisciplinary discussion and informed consent of the patient. The examination by sEEG led to a change of plan for further treatment in 13 patients (61.9%) suffering TLE in total. Invasive monitoring with sEEG electrodes had a strong impact on decision-making for further treatment in patients suffering from temporal lobe epilepsy with incongruent findings in presurgical examination designated for epilepsy surgery. This applies to resection volumes as well as to prediction of seizure outcome.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s10143-019-01175-4DOI Listing
October 2020

DNA damage kinase signaling: checkpoint and repair at 30 years.

EMBO J 2019 09 8;38(18):e101801. Epub 2019 Aug 8.

Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY, USA.

From bacteria to mammalian cells, damaged DNA is sensed and targeted by DNA repair pathways. In eukaryotes, kinases play a central role in coordinating the DNA damage response. DNA damage signaling kinases were identified over two decades ago and linked to the cell cycle checkpoint concept proposed by Weinert and Hartwell in 1988. Connections between the DNA damage signaling kinases and DNA repair were scant at first, and the initial perception was that the importance of these kinases for genome integrity was largely an indirect effect of their roles in checkpoints, DNA replication, and transcription. As more substrates of DNA damage signaling kinases were identified, it became clear that they directly regulate a wide range of DNA repair factors. Here, we review our current understanding of DNA damage signaling kinases, delineating the key substrates in budding yeast and humans. We trace the progress of the field in the last 30 years and discuss our current understanding of the major substrate regulatory mechanisms involved in checkpoint responses and DNA repair.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.15252/embj.2019101801DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6745504PMC
September 2019

Mec1 Autophosphorylation and Ddc2 Phosphorylation Regulates DNA Damage Checkpoint Signaling.

Cell Rep 2019 07;28(4):1090-1102.e3

Department of Biology and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA 02454, USA. Electronic address:

In budding yeast, a single DNA double-strand break (DSB) triggers the activation of Mec1-dependent DNA damage checkpoint. After about 12 h, cells turn off the checkpoint signaling and adapt despite the persistence of the DSB. We report that the adaptation involves the autophosphorylation of Mec1 at site S1964. A non-phosphorylatable mec1-S1964A mutant causes cells to arrest permanently in response to a single DSB without affecting the initial kinase activity of Mec1. Autophosphorylation of S1964 is dependent on Ddc1 and Dpb11, and it correlates with the timing of adaptation. We also report that Mec1's binding partner, Ddc2, is an inherently stable protein that is degraded specifically upon DNA damage. Ddc2 is regulated extensively through phosphorylation, which, in turn, regulates the localization of the Mec1-Ddc2 complex to DNA lesions. Taken together, these results suggest that checkpoint response is regulated through the autophosphorylation of Mec1 kinase and through the changes in Ddc2 abundance and phosphorylation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.celrep.2019.06.068DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7218798PMC
July 2019

The importance of size, location, and vegetation composition of perennial fallows for farmland birds.

Ecol Evol 2018 Sep 24;8(18):9270-9281. Epub 2018 Aug 24.

Swiss Ornithological Institute Sempach Switzerland.

Across Europe, patches of un-cropped land (field margins, fallows, etc.) have been established and managed as part of agri-environment schemes (AES) to counteract the decrease in farmland biodiversity. Various studies demonstrate a positive impact of such un-cropped land on different taxa. However, there is potential to further improve the efficiency of fallow options for farmland birds. In a long-term monitoring, 12 breeding farmland bird species and sizes of perennial fallows were recorded from 1992 to 2015 in a 6.1 km area in Switzerland. Furthermore, habitat composition and fallow characteristics were mapped in 2012. We calculated population trends, analyzed habitat associations and revealed the impact of fallow habitat characteristics on territory density. The proportion of fallows in the study site increased from 1.4% (1992) to 8.5% (2012). Population trends of six of 12 censused species increased significantly over the same time, four species showed no trend and trends of two species decreased. Seven species were analyzed in more detail, for five of them fallows were overrepresented around their territory center points compared to arable fields and grassland. The overall territory density of these five species was higher in small fallows which were not placed next to a wood and which held bramble spp., shrubs and the tall-growing forb goldenrod ( and ). Our study confirms that perennial fallows are a highly suitable option to support different farmland birds in arable landscapes. Yet, we recommend optimizing fallows through careful site selection and management, such that they are not established on shady locations and are structurally diverse by allowing brambles, shrubs, and tall-growing forbs to occur. We suggest adapting the Swiss AES in this regard. Biodiversity-related advisory services available for farmers could increase the probability that fallow options are implemented and managed properly for targeted species.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/ece3.4420DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6194211PMC
September 2018

SUDEP following the second seizure in new-onset epilepsy due to limbic encephalitis.

Seizure 2018 11 10;62:124-126. Epub 2018 Oct 10.

Protestant Hospital Alsterdorf, Epilepsy Center Hamburg, Elisabeth-Flügge-Str. 1, 22337 Hamburg, Germany. Electronic address:

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.seizure.2018.10.007DOI Listing
November 2018

Separable roles for Mec1/ATR in genome maintenance, DNA replication, and checkpoint signaling.

Genes Dev 2018 06 13;32(11-12):822-835. Epub 2018 Jun 13.

Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, New York 14853, USA.

The Mec1/ATR kinase coordinates multiple cellular responses to replication stress. In addition to its canonical role in activating the checkpoint kinase Rad53, Mec1 also plays checkpoint-independent roles in genome maintenance that are not well understood. Here we used a combined genetic-phosphoproteomic approach to manipulate Mec1 activation and globally monitor Mec1 signaling, allowing us to delineate distinct checkpoint-independent modes of Mec1 action. Using cells in which endogenous Mec1 activators were genetically ablated, we found that expression of "free" Mec1 activation domains (MADs) can robustly activate Mec1 and rescue the severe DNA replication and growth defects of these cells back to wild-type levels. However, unlike the activation mediated by endogenous activator proteins, "free" MADs are unable to stimulate Mec1-mediated suppression of gross chromosomal rearrangements (GCRs), revealing that Mec1's role in genome maintenance is separable from a previously unappreciated proreplicative function. Both Mec1's functions in promoting replication and suppressing GCRs are independent of the downstream checkpoint kinases. Additionally, Mec1-dependent GCR suppression seems to require localized Mec1 action at DNA lesions, which correlates with the phosphorylation of activator-proximal substrates involved in homologous recombination-mediated DNA repair. These findings establish that Mec1 initiates checkpoint signaling, promotes DNA replication, and maintains genetic stability through distinct modes of action.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1101/gad.308148.117DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6049512PMC
June 2018

Quantitative Analysis of DNA Damage Signaling Responses to Chemical and Genetic Perturbations.

Methods Mol Biol 2018 ;1672:645-660

Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, 339 Weill Hall, Ithaca, NY, 14853-7202, USA.

Phosphorylation-mediated signaling is essential for maintenance of the eukaryotic genome. The evolutionarily conserved kinases ATR and ATM sense specific DNA structures generated upon DNA damage or replication stress and mediate an extensive signaling network that impinges upon most nuclear processes. ATR/ATM signaling is highly regulated and can function in a context-dependent manner. Thus, the ability to quantitatively monitor most, if not all, signaling events in this network is essential to investigate the mechanisms by which kinases maintain genome integrity. Here we describe a method for the Quantitative Mass-Spectrometry Analysis of Phospho-Substrates (QMAPS) to monitor in vivo DNA damage signaling in a systematic, unbiased, and quantitative manner. Using the model organism Saccharomyces cerevisiae, we provide an example for how QMAPS can be applied to define the effect of genotoxins, illustrating the importance of quantitatively monitoring multiple kinase substrates to comprehensively understanding kinase action. QMAPS can be easily extended to other organisms or signaling pathways where kinases can be deleted or inhibited.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/978-1-4939-7306-4_42DOI Listing
June 2018

Stability of medicines after repackaging into multicompartment compliance aids: eight criteria for detection of visual alteration.

Drugs Ther Perspect 2017 26;33(10):487-496. Epub 2017 Jul 26.

Pharmaceutical Care Research Group, University of Basel, Klingelbergstrasse 50, 4056 Basel, Switzerland.

Introduction: Multicompartment compliance aids (MCA) are widely used by patients. They support the management of medication and reduce unintentional nonadherence. MCA are filled with medicines unpacked from their original packaging. Swiss pharmacists currently provide MCA for 1-2 weeks, although little and controversial information exists on the stability of repackaged medicines.

Objective: We aimed to validate the usefulness of a simple screening method capable of detecting visual stability problems with repackaged medicines.

Methods: We selected eight criteria for solid formulations from : (1) rough surface, (2) chipping, (3) cracking, (4) capping, (5) mottling, (6) discoloration, (7) swelling, and (8) crushing. A selection of 24 critical medicines was repackaged in three different MCA (Pharmis, SureMed™, and self-produced blister) and stored at room temperature for 4 weeks. Pharmis was additionally stored at accelerated conditions. Appearance was scored weekly.

Results: Six alterations (rough surface, cracking, mottling, discoloration, swelling, and crushing) were observed at accelerated conditions. No alteration was observed at room temperature, except for the chipping of tablets that had been stuck to cold seal glue.

Conclusion: The eight criteria can detect alterations of the appearance of oral solid medicines repackaged in MCA. In the absence of specific guidelines, they can serve as a simple screening method in community pharmacies for identifying medicines unsuitable for repackaging.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s40267-017-0431-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5610216PMC
July 2017

Effects of a sustained release formulation of 1,25-dihydroxyvitamin D3-glycosides for milk fever prevention on serum 1,25-dihydroxyvitamin D3, calcium and phosphorus in dairy cows.

J Steroid Biochem Mol Biol 2017 10 23;173:301-307. Epub 2017 Mar 23.

Institute for Animal Nutrition, Ludwig Maximilians University München, D-85764 Oberschleissheim, Germany. Electronic address:

Milk fever (MF) is a metabolic disease in dairy cows around parturition. The clinical lead sign is muscular paresis leading in severe cases to paralysis of the affected animal. Multiparturient animals of high performing dairy breeds are most likely to be affected and have a high probability of recurrence. An acute drop in blood calcium levels causes the disease when the demand for calcium at the onset of lactation exceeds the ability to replete blood calcium levels through mobilization from bone and intestinal uptake. With the understanding of the underlying mechanism, calcium supply management and vitamin D supplementation became prime candidates for MF prevention and therapy. Several strategies have been developed for MF prevention. Application of the active form of Vitamin D, 1,25(OH)D, was found to prevent MF effectively. In order to prevent a delayed hypocalcemia, which was occasionally seen after stopping the treatment with 1,25(OH)D a new approach was chosen by applying Solanum glaucophyllum extract (SGE), which contains 1,25(OH)D-glycosides, as instant-release (irSGE) in combination with slow-release (srSGE) tablets. In a first study, non-lactating cows were treated with a single bolus of either synthetic 1,25(OH)D, irSGE, or srSGE and the results were compared to a control group without treatment. Blood serum levels of 1,25(OH)D (1,25D), calcium (Ca), phosphate (P) and magnesium (Mg) were followed for 11days and the area under the curve (AUC) was calculated. Calcium and phosphate excretion in urine were determined during 15days. While serum concentration of 1,25(OH)D was back to pre-treatment level in the irSGE, srSGE and 1,25(OH)D treated group within 3days, calcium and phosphate levels remained elevated for up to 9days. AUC of serum 1,25(OH)D was 2.89 (1,25D), 3.13 (irSGE) and 4.21 (srSGE) times higher than control. Serum calcium levels were 1.07 (for 1.25D); 1.08 (for irSGE) and 1.12 (for srSGE) times higher than control. Serum phosphate levels were 1.20 (for 1,25D); 1.30 (for irSGE) and 1.41 (for srSGE) times higher than control, with p<0.05. In a second field study calving cows treated with one bolus containing ir- and sr- tablets of SGE were compared to an untreated control group and to a group treated with 4 boli of commercial calcium salts. As a result, calcium serum levels increased (+19% compared to baseline) around calving after treatment with the single bolus of SGE. The single bolus of SGE lead also to an increase of serum phosphate (+31% compared to baseline). These calcium and phosphate increases were statistically significant (p<0.001) 0-24h after calving compared to the control group and to the group treated with calcium salts. The sample size of the study was too small to draw a conclusion on the effect on MF prevention. In conclusion, application of a single bolus of a SGE extract lead to an increase of serum calcium and phosphate for up to 9days and may thus have the potential to prevent a hypocalcemia and -phosphatemia, an important cause for clinical milk fever.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jsbmb.2017.03.020DOI Listing
October 2017

Kinesin-2 and Apc function at dendrite branch points to resolve microtubule collisions.

Cytoskeleton (Hoboken) 2016 Jan;73(1):35-44

Huck Institutes of the Life Sciences and Biochemistry and Molecular Biology, the Pennsylvania State University, University Park, Pennsylvania.

In Drosophila neurons, kinesin-2, EB1 and Apc are required to maintain minus-end-out dendrite microtubule polarity, and we previously proposed they steer microtubules at branch points. Motor-mediated steering of microtubule plus ends could be accomplished in two ways: 1) by linking a growing microtubule tip to the side of an adjacent microtubule as it navigates the branch point (bundling), or 2) by directing a growing microtubule after a collision with a stable microtubule (collision resolution). Using live imaging to distinguish between these two mechanisms, we found that reduction of kinesin-2 did not alter the number of microtubules that grew along the edge of the branch points where stable microtubules are found. However, reduction of kinesin-2 or Apc did affect the number of microtubules that slowed down or depolymerized as they encountered the side of the branch opposite to the entry point. These results are consistent with kinesin-2 functioning with Apc to resolve collisions. However, they do not pinpoint stable microtubules as the collision partner as stable microtubules are typically very close to the membrane. To determine whether growing microtubules were steered along stable ones after a collision, we analyzed the behavior of growing microtubules at dendrite crossroads where stable microtubules run through the middle of the branch point. In control neurons, microtubules turned in the middle of the crossroads. However, when kinesin-2 was reduced some microtubules grew straight through the branch point and failed to turn. We propose that kinesin-2 functions to steer growing microtubules along stable ones following collisions.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/cm.21270DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5093339PMC
January 2016

Morphometric MRI analysis enhances visualization of cortical tubers in tuberous sclerosis.

Epilepsy Res 2015 Nov 8;117:29-34. Epub 2015 Aug 8.

Swiss Epilepsy Centre, Zürich, Switzerland.

Purpose: Focal cortical dysplasias (FCD) type IIb and cortical tubers in tuberous sclerosis complex (TSC) are histopathologically similar and are both epileptogenic lesions frequently causing pharmacoresistant epilepsies. Morphometric analysis of T1- and T2-weighted MRI volume data sets can enhance visualization of FCD. Here, we retrospectively investigated whether morphometric MRI analysis is of equal benefit for visualizing cortical tubers.

Materials And Methods: Morphometric analysis was applied to T1- and partly also T2-weighted 1.5T or 3T MRI volume data sets of 15 TSC patients using a fully automated MATLAB(®) script (i.e. MAP07) commonly used for FCD detection. In this study, focus was on the most sensitive of the resulting morphometric feature maps (i.e. the 'junction image') which highlights blurring of the gray-white matter junction in comparison to a normal database. The visualization of tubers in these 'junction images' was quantitatively compared with that in conventional MR sequences.

Results: In all patients, morphometric analysis visualized almost all tubers detected in the normal MRI, and additionally highlighted on average 23% (range 3-50%) more tubers which were not detected by visual analysis of the conventional MR sequences. When T2 volume data sets from a 3T scanner were available for postprocessing, the rate of additionally detected tubers increased to 29% on average. These formerly overlooked tubers were usually smaller than the tubers already found in the conventional MRI.

Conclusion: Morphometric analysis of MRIs in TSC can highlight cortical tubers which are likely to be overlooked in conventional MRI sequences alone. Additionally detected tubers may be of potential importance for both presurgical evaluation and initial diagnosis of TSC.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.eplepsyres.2015.08.002DOI Listing
November 2015

Chewability testing in the development of a chewable tablet for hyperphosphatemia.

Drug Dev Ind Pharm 2014 Dec 6;40(12):1623-31. Epub 2013 Sep 6.

Institute of Pharmaceutical Technology, School of Life Sciences - FHNW, Gründenstrasse 40 , Muttenz , Switzerland .

The official Pharmacopeia does not include a test procedure for the in vitro estimation of the chewability of tablets and publications in the scientific literature on this subject are rare. The purpose of this study was to evaluate a number of different test procedures for assessing chewability, starting from standard breaking force and strength testing and progressing to develop new procedures that simulate the actual chewing action on tablets. A further goal was to apply these test procedures to characterize the chewability of the novel phosphate binder PA21 in comparison with a commercially available phosphate binder chewable tablet product based on lanthanum (Fosrenol®) and a chewable tablet product containing calcium (Calcimagon®) - the latter being used as a standard for its very good chewability. For this purpose, a number of development formulations (different batches of PA21) were tested. The radial or diametrical tablet breaking force offers a poor means of assessing chewability while the axial breaking force was concluded to better reflect the effect of chewing on the tablet. Measurement of tablet behavior upon repeated loading afforded the best simulation of the actual chewing action and was found to have a good discriminating power with respect to chewability of the tested tablets, especially when the tablet was moistened with artificial saliva. The developed tests are shown to be more suitable for evaluating chewing properties of tablets than currently used Pharmacopeial tests. Following ICHQ6, which calls for specification of hardness for chewable tablets, these test procedures enabled the optimal chewability features of PA21 tablets in development to be confirmed whilst still maintaining capabilities for robust production and transportation processes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3109/03639045.2013.838583DOI Listing
December 2014

Comparison of morphometric analysis based on T1- and T2-weighted MRI data for visualization of focal cortical dysplasia.

Epilepsy Res 2013 Oct 25;106(3):403-9. Epub 2013 Jul 25.

Hamburg Epilepsy Center, Protestant Hospital Alsterdorf, Bodelschwinghstr. 24, 22337 Hamburg, Germany. Electronic address:

Purpose: Focal cortical dysplasias (FCD) are highly epileptogenic lesions frequently accounting for pharmaco-resistant focal epilepsy. Visual MRI analysis combined with morphometric analysis of T1-weighted MRI data was shown to be of higher diagnostic sensitivity in detecting and delineating FCD than conventional visual analysis alone. Here we investigate whether morphometric analysis of T2-weighted MRI volume data sets is of equal benefit or perhaps more helpful for visualizing FCD.

Materials And Methods: Morphometric analysis was applied to T1- and T2-weighted MRI volume data sets of 20 epilepsy patients with FCD using a fully automated MATLAB script with scanner- and sequence-specific normal databases for T1 and T2 images. For each modality, a new feature map (i.e., 'junction image') highlighting the FCD-typical blurring of the gray-white matter junction and quantifying this feature in comparison to the normal database in terms of z-scores was calculated. The resulting T1 and T2 'junction images' were compared for conspicuity and recognizability of the FCD both qualitatively by visual assessment and quantitatively by analysis of the mean z-scores inside and outside the lesions.

Results: In 80% of the cases, the FCD presented with higher contrast and/or clearer delineation in the T2 than in the T1 'junction images' and were thus easier to recognize in these images. The quantitative analysis supported this impression: in 95% of cases, the ratio of mean z-scores inside and outside the FCD was higher in T2- than in T1-based 'junction images'. For the T2 'junction images', this ratio amounted to 8.7 on average and was thus more than twice as high as the corresponding T1 result of 3.7 (p<.003).

Conclusion: Concerning visualization of FCD by highlighting blurring of the gray-white matter junction, the results of the present study indicate that morphometric analysis of T2-weighted MRI data on average is superior to T1-based morphometry.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.eplepsyres.2013.06.016DOI Listing
October 2013

Occipital lobe epilepsy with fear as leading ictal symptom.

Epilepsy Behav 2012 Mar 27;23(3):379-83. Epub 2012 Feb 27.

Epilepsy Center, University Hospital Freiburg, Breisacher Straße 64, 79106 Freiburg, Germany.

Ictal fear is a semiological feature which is commonly associated with mesial temporal lobe epilepsy. Here, we describe fear as a leading symptom in cryptogenic occipital lobe epilepsy. In a patient with negative MRI findings, intracranial EEG recordings documented a strict correlation between habitual ictal anxiety attacks and both spontaneous and stimulation-induced epileptic activity in a right occipital epileptogenic area with subsequent spreading to the symptomatogenic zone in the amygdala. Circumscribed occipital topectomy led to seizure freedom. Episodes of non-epileptic fear ceased shortly afterwards. This report provides insight into pathways of propagation of epileptic activity, illustrates different etiologies of pathologic fear and underlines the importance of ictal EEG recordings.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.yebeh.2011.12.014DOI Listing
March 2012

Comparison of diffusion tensor-based tractography and quantified brain atrophy for analyzing demyelination and axonal loss in MS.

J Neuroimaging 2010 Oct;20(4):334-44

From the Klinikum Bremen-Ost, Department of Neurology, Bremen, Germany.

We combined diffusion tensor imaging (DTI) measures of the corpus callosum (CC) and the superior longitudinal fascicle (SLF) with calculation of brain atrophy in 53 patients with relapsing-remitting multiple sclerosis (MS) and 15 healthy controls, to analyze their interrelation and their correlation with disease duration and clinical impairment. The lateral ventricle volume in MS patients was increased; the fractional anisotropy in the CC was decreased as was the fiber volume. Perpendicular (in the literature also referred to as radial) diffusivity (ped), which reflects the diffusion perpendicular to the long axis of the axons within the fiber bundle, was increased in the SLF and the posterior CC, but contrary to our predictions, parallel (also called axial) diffusivity (pad) that refers to the amount of diffusion in the direction of the axon was increased, too. Brain atrophy and DTI-derived parameters were highly intercorrelated and both correlated with disease duration. Discriminant analysis showed that DTI-derived atrophy measures are superior to brain atrophy measures in classifying patients and controls. In light of our results, animal studies focusing on demyelination and axonal loss are reinterpreted.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/j.1552-6569.2009.00377.xDOI Listing
October 2010

Breath holding - A rapid eye movement (REM) sleep parasomnia (catathrenia or expiratory groaning).

Sleep Med 2008 May 17;9(4):455-6. Epub 2007 Oct 17.

Department of Clinical Neurophysiology, Klinikum Bremen-Ost/University of Göttingen, Germany.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.sleep.2007.08.008DOI Listing
May 2008

[When the legs have to keep moving at night--the restless legs syndrome].

MMW Fortschr Med 2007 May;149 Suppl 2:42-4

Abteilung für Klinische Neurophysiologie, Klinikum Bremen-Ost.

The restless legs syndrome (RLS) is a frequently occurring neurological disease that is often associated with sleep disorders and reduced quality of life. The cause of RLS still has not been clearly established; however, the dopaminergic and opioid systems and iron metabolism appear to have major roles in the disease. The therapy of choice is treatment with dopaminergic drugs. In addition, opiates and anticonvulsants such as gabapentin are used. The most important side effect of dopaminergic therapy is augmentation. If therapy-related augmentation occurs while taking levodopa, the medication should be changed to dopamine agonists. If augmentation occurs while taking dopamine agonists, opiates or gabapentin should be taken instead.
View Article and Find Full Text PDF

Download full-text PDF

Source
May 2007

Brain atrophy and cognitive impairment in multiple sclerosis: a review.

J Neurol 2007 May;254 Suppl 2:II43-8

Dept. of Neurology, Klinikum Bremen-Ost, Züricher Str. 40, 28325, Bremen, Germany.

Multiple sclerosis (MS) is a common neurological disease in the Western hemisphere that leads to neurological dysfunctions and frequently from its onset to cognitive impairment, which together predict quality of life. Recent pathological and imaging studies have focused on brain atrophy representing axonal injury and loss as being crucial for developing disability and neuropsychological impairment. Brain atrophy has therefore been proposed to be a tool for monitoring disease progress. Here, we review the possible origins of brain atrophy and its correlation with cognitive impairment in MS.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00415-007-2011-8DOI Listing
May 2007

Cognitive training in MS: effects and relation to brain atrophy.

Restor Neurol Neurosci 2007 ;25(1):33-43

Klinikum Bremen-Ost, Department of Neurology, Züricher Str. 40, 28325 Bremen, Germany.

Purpose: Cognitive disorders are common in MS patients without any generally recommended treatment. Recent brain imaging studies show considerable neuroplasticity for cognitive tasks in MS patients, but also brain atrophy already early in the disease progression. We explored the benefits of a home-based cognitive training program for memory and working memory functions in relapsing-remitting MS patients controlling for whole brain and central brain atrophy as covariates.

Methods: Using a single-blinded controlled study design, 42 patients were randomised into a treatment group and a control group. Home based computer training focusing on memory and working memory was started at least 4 weeks after the discontinuation of methylprednisolone treatment and lasted for 6 weeks. Two weeks later the patients were re-investigated for their clinical and cognitive performance. We assessed also quality of life (QoL), depression and fatigue using self-rating scales.

Results: Training had no effect on the neurological status and on QoL or fatigue. However, the treatment group showed better verbal learning, long-delay verbal memory performance, and working memory performance. The impact of treatment on long-delay verbal memory performance was independent from the extent of brain atrophy, whereas for the other findings brain atrophy played a significant role.

Conclusions: An intensive home-based cognitive training program is suitable to improve the cognitive performance of MS patients. The impact of brain atrophy on rehabilitation outcome may differ for cognitive functions.
View Article and Find Full Text PDF

Download full-text PDF

Source
August 2007

Response shifting and inhibition, but not working memory, are impaired after long-term heavy alcohol consumption.

Neuropsychology 2004 Apr;18(2):203-11

Department of Neurology, Municipal Hospital of Bremen, Bremen, Germany.

Chronic alcohol abuse leads to cognitive deficits. The authors investigated whether a systematic increase of interference in a 2-back working memory paradigm would lead to cognitive deficits in alcoholic participants and compared their performance in such a task with that in an alternate-response task. Twenty-four nonamnesic and nondemented alcohol abuse (AA) patients and 12 patients with Korsakoff's syndrome (KS) were compared with a control group. AA patients were impaired in the alternate-response task but not in working memory interference resolution. KS patients performed worse than the AA patients and the controls in both tasks. The neurotoxic side effects of alcohol therefore lead to a specific deficit in alternating between response rules but not in working memory, independently of whether the working memory task involves interference resolution or not.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1037/0894-4105.18.2.203DOI Listing
April 2004