Differential effects of dual and unihemispheric motor cortex stimulation in older adults

Bihemispheric transcranial direct current stimulation (tDCS) is thought to upregulate excitability of the primary motor cortex (M1) using anodal stimulation while concurrently downregulating contralateral M1 using cathodal stimulation. This “dual” tDCS method enhances motor learning in healthy subjects and facilitates motor recovery after stroke. However, its impact on motor system activity and connectivity remains unknown. Therefore, we assessed neural correlates of dual and unihemispheric anodal tDCS effects in 20 healthy older subjects in a randomized, sham-controlled study using a cross-over design. Participants underwent tDCS and simultaneous functional magnetic resonance imaging during a choice reaction time task and at rest. Diffusion tensor imaging (DTI) allowed us to relate potential functional changes to structural parameters. The resting-state analysis demonstrated that, compared with sham, both dual and anodal tDCS decreased connectivity of right hippocampus and M1 (contralateral to the anode position) while increasing connectivity in the left prefrontal cortex. Notably, dual but not anodal tDCS enhanced connectivity of the left dorsal posterior cingulate cortex. Furthermore, dual tDCS yielded stronger activations in bilateral M1 compared with anodal tDCS when participants used either their left or right hand during the motor task. The corresponding tDCS-induced changes in laterality of activations were related to the microstructural status of transcallosal motor fibers. In conclusion, our results suggest that the impact of bihemispheric tDCS cannot be explained by mere add-on effects of anodal and concurrent cathodal stimulation, but rather by complex network modulations involving interhemispheric interactions and areas associated with motor control in the dorsal posterior cingulate cortex

Effects of transcranial direct current stimulation on neural networks in young and older adults

Transcranial direct current stimulation (tDCS) may be a viable tool to improve motor and cognitive function in advanced age. However, although a number of studies have demonstrated improved cognitive performance in older adults, other studies have failed to show restorative effects. The neural effects of beneficial stimulation response in both age groups is lacking. In the current study, tDCS was administered during simultaneous fMRI in 42 healthy young and older participants. Semantic word generation and motor speech baseline tasks were used to investigate behavioral and neural effects of uni-and bihemispheric motor cortex tDCS in a three-way, crossover, sham tDCS controlled design. Independent components analysis assessed differences in task-related activity between the two age groups and tDCS effects. at the network level. We also explored whether laterality of language network organization was effected by tDCS. Behaviorally, both active tDCS conditions significantly improved semantic word retrieval performance in young and older adults and were comparable between groups and stimulation conditions. Network-level tDCS effects were identified in the ventral and dorsal anterior cingulate networks in the combined sample during semantic fluency and motor speech tasks. In addition, a shift toward enhanced left laterality was identified in the older adults for both active stimulation conditions. Thus, tDCS results in common network-level modulations and behavioral improvements for both age groups, with an additional effect of increasing left laterality in older adults

Acetylation Suppresses the Proapoptotic Activity of GD3 Ganglioside

GD3 synthase is rapidly activated in different cell types after specific apoptotic stimuli. De novo synthesized GD3 accumulates and contributes to the apoptotic program by relocating to mitochondrial membranes and inducing the release of apoptogenic factors. We found that sialic acid acetylation suppresses the proapoptotic activity of GD3. In fact, unlike GD3, 9-O-acetyl-GD3 is completely ineffective in inducing cytochrome c release and caspase-9 activation on isolated mitochondria and fails to induce the collapse of mitochondrial transmembrane potential and cellular apoptosis. Moreover, cells which are resistant to the overexpression of the GD3 synthase, actively convert de novo synthesized GD3 to 9-O-acetyl-GD3. The coexpression of GD3 synthase with a viral 9-O-acetyl esterase, which prevents 9-O-acetyl-GD3 accumulation, reconstitutes GD3 responsiveness and apoptosis. Finally, the expression of the 9-O-acetyl esterase is sufficient to induce apoptosis of glioblastomas which express high levels of 9-O-acetyl-GD3. Thus, sialic acid acetylation critically controls the proapoptotic activity of GD3

RV POSEIDON Cruise Report POS473 LORELEI II: LOphelia REef Lander Expedition and Investigation II, Tromsø – Bergen – Esbjerg, 15.08. – 31.08. – 04.09.2014

As a result of the raising CO2-emissions and the resultant ocean acidification (decreasing pH and carbonate ion concentration), the impact on marine organism that build their skeletons and protective shells with calcium carbonate (e.g., mollusks, sea urchins, coccolithophorids, and stony corals) becomes more and more detrimental. In the last few years, many experiments with tropical reef building corals have shown, that a lowering of the carbonate ion concentration significantly reduces calcification rates and therefore growth (e.g., Gattuso et al. 1999; Langdon et al. 2000, 2003; Marubini et al. 2001, 2002). In the middle of this century, many tropical coral reefs may well erode faster than they can rebuild. Cold-water corals are living in an environment (high geographical latitude, cold and deep waters) already close to a critical carbonate ion concentration below calcium carbonate dissolves. Actual projections indicate that about 70% of the currently known Lophelia reef structures will be in serious danger until the end of the century (Guinotte et al. 2006). Therefore L. pertusa was cultured at GEOMAR to determine its long-term response to ocean acidification. Our work has revealed that – unexpectedly and controversially to the majority of warm-water corals – this species is potentially able to cope with elevated concentrations of CO2. Whereas short-term (1 week) high CO2 exposure resulted in a decline of calcification by 26-29 % for a pH decrease of 0.1 units and net dissolution of calcium carbonate, L. pertusa was capable to acclimate to acidified conditions in long-term (6 months) incubations, leading to slightly enhanced rates of calcification (Form & Riebesell, 2012). But all these studies were carried out in the laboratory under controlled conditions without considering natural variability and ecosystem interactions with the associated fauna. Moreover, only very little is known about the nutrition (food sources and quantity) of cold-water corals in their natural habitat. In a multifactorial laboratory study during BIOACID phase II we could show that food availability is one of the key drivers that promote the capability of these organisms to withstand environmental pressures such as alterations in the carbonate chemistry and temperature (Büscher, Form & Riebesell, in prep.). To take into account the influences of natural fluctuations and interactions (e.g. bioerosion), we aim to merge in-situ results from the two research cruises POS455 and POS473 with laboratory experimental studies for a comprehensive understanding of likely ecosystem responses under past, present and future environmental conditions

A combined approach of MALDI-TOF mass spectrometry and multivariate analysis as a potential tool for the detection of SARS-CoV-2 virus in nasopharyngeal swabs

Coronavirus disease 2019, known as COVID-19, is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The early, sensitive and specific detection of SARS-CoV-2 virus is widely recognized as the critical point in responding to the ongoing outbreak. Currently, the diagnosis is based on molecular real time RT-PCR techniques, although their implementation is being threatened due to the extraordinary demand for supplies worldwide. That is why the development of alternative and / or complementary tests becomes so relevant. Here, we exploit the potential of mass spectrometry technology combined with machine learning algorithms, for the detection of COVID-19 positive and negative protein profiles directly from nasopharyngeal swabs samples. According to the preliminary results obtained, accuracy =67.66 %, sensitivity =61.76 %, specificity =71.72 %, and although these parameters still need to be improved to be used as a screening technique, mass spectrometry- based methods coupled with multivariate analysis showed that it is an interesting tool that deserves to be explored as a complementary diagnostic approach due to the low cost and fast performance. However, further steps, such as the analysis of a large number of samples, should be taken in consideration to determine the applicability of the method developed.Fil: Rocca, María Florencia. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud "Dr. C. G. Malbrán"; Argentina. Universidad Nacional de Santiago del Estero. Facultad de Humanidades Ciencias Sociales y de la Salud. Instituto de Estudios e Investigaciones en Enfermería; Argentina. Red Nacional de Espectrometría de Masas Aplicada a la Microbiología Clínica; ArgentinaFil: Zintgraff, Jonathan Cristian. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud "Dr. C. G. Malbrán"; Argentina. Universidad Nacional de Santiago del Estero. Facultad de Humanidades Ciencias Sociales y de la Salud. Instituto de Estudios e Investigaciones en Enfermería; Argentina. Red Nacional de Espectrometría de Masas Aplicada a la Microbiología Clínica; ArgentinaFil: Dattero, María Elena. Universidad Nacional de Santiago del Estero. Facultad de Humanidades Ciencias Sociales y de la Salud. Instituto de Estudios e Investigaciones en Enfermería; Argentina. Administración Nacional de Laboratorios e Institutos de Salud "Dr. Carlos G. Malbrán". Instituto Nacional de Medicina Tropical; ArgentinaFil: Santos, Leonardo Silva. Universidad de Talca; ChileFil: Ledesma, Martin Manuel. Red Nacional de Espectrometría de Masas Aplicada A la Microbiología Clínica (renaem Argentina); Argentina. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Vay, Carlos Alberto. Red Nacional de Espectrometría de Masas Aplicada a la Microbiología Clínica; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; ArgentinaFil: Prieto, Mónica Raquel. Red Nacional de Espectrometría de Masas Aplicada a la Microbiología Clínica; Argentina. Universidad de Buenos Aires; ArgentinaFil: Benedetti, Estefanía. Universidad Nacional de Santiago del Estero. Facultad de Humanidades Ciencias Sociales y de la Salud. Instituto de Estudios e Investigaciones en Enfermería; Argentina. Administración Nacional de Laboratorios e Institutos de Salud "Dr. Carlos G. Malbrán". Instituto Nacional de Medicina Tropical; ArgentinaFil: Avaro, Martín. Universidad Nacional de Santiago del Estero. Facultad de Humanidades Ciencias Sociales y de la Salud. Instituto de Estudios e Investigaciones en Enfermería; Argentina. Administración Nacional de Laboratorios e Institutos de Salud "Dr. Carlos G. Malbrán". Instituto Nacional de Medicina Tropical; ArgentinaFil: Russo, Mara Laura. Universidad Nacional de Santiago del Estero. Facultad de Humanidades Ciencias Sociales y de la Salud. Instituto de Estudios e Investigaciones en Enfermería; Argentina. Administración Nacional de Laboratorios e Institutos de Salud "Dr. Carlos G. Malbrán". Instituto Nacional de Medicina Tropical; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Nachtigall, Fabiane Manke. Universidad Autónoma de Chile; ChileFil: Baumeister, Elsa. Universidad Nacional de Santiago del Estero. Facultad de Humanidades Ciencias Sociales y de la Salud. Instituto de Estudios e Investigaciones en Enfermería; Argentina. Administración Nacional de Laboratorios e Institutos de Salud "Dr. Carlos G. Malbrán". Instituto Nacional de Medicina Tropical; Argentin

Organic matter fluxes and biogeochemical processes in the OMZ off Peru, Cruise No. M138, 01 June - 03 July 2017, Callao (Peru) - Bahia Las Minas (Panama)

The oxygen minimum zone (OMZ) in the eastern tropical South Pacific Ocean is tightly connected to the coastal upwelling system off Peru. The high biological productivity off Peru is therefore, driven by the complex interplay between the amount of nutrients recycled by remineralisation processes in the OMZ and the upwelling which brings these nutrients to the surface layer. However, surprisingly little is known about organic matter cycling and its effects on biogeochemical processes in the OMZ off Peru. To this end we conducted a first comprehensive study on the role of organic matter for the biogeochemical processes and the maintenance of the OMZ off Peru. M138 combined measurements of marine biogeochemistry, microbiology, physical oceanography and air chemistry with foci on (i) the efficiency of the biological pump, (ii) the nitrogen cycle processes in the OMZ, (iii) the ventilation of the OMZ as well as (iv) the air/sea gas exchange across the ocean/atmosphere interface and (v) aerosol deposition. The METEOR cruise M138 was performed as part of the third phase of the SFB754 'Climate-Biogeochemistry Interactions in the Tropical Ocean' (www.sfb754.de)

Significant benefits of AIP testing and clinical screening in familial isolated and young-onset pituitary tumors

Context Germline mutations in the aryl hydrocarbon receptor-interacting protein (AIP) gene are responsible for a subset of familial isolated pituitary adenoma (FIPA) cases and sporadic pituitary neuroendocrine tumors (PitNETs). Objective To compare prospectively diagnosed AIP mutation-positive (AIPmut) PitNET patients with clinically presenting patients and to compare the clinical characteristics of AIPmut and AIPneg PitNET patients. Design 12-year prospective, observational study. Participants & Setting We studied probands and family members of FIPA kindreds and sporadic patients with disease onset ≤18 years or macroadenomas with onset ≤30 years (n = 1477). This was a collaborative study conducted at referral centers for pituitary diseases. Interventions & Outcome AIP testing and clinical screening for pituitary disease. Comparison of characteristics of prospectively diagnosed (n = 22) vs clinically presenting AIPmut PitNET patients (n = 145), and AIPmut (n = 167) vs AIPneg PitNET patients (n = 1310). Results Prospectively diagnosed AIPmut PitNET patients had smaller lesions with less suprasellar extension or cavernous sinus invasion and required fewer treatments with fewer operations and no radiotherapy compared with clinically presenting cases; there were fewer cases with active disease and hypopituitarism at last follow-up. When comparing AIPmut and AIPneg cases, AIPmut patients were more often males, younger, more often had GH excess, pituitary apoplexy, suprasellar extension, and more patients required multimodal therapy, including radiotherapy. AIPmut patients (n = 136) with GH excess were taller than AIPneg counterparts (n = 650). Conclusions Prospectively diagnosed AIPmut patients show better outcomes than clinically presenting cases, demonstrating the benefits of genetic and clinical screening. AIP-related pituitary disease has a wide spectrum ranging from aggressively growing lesions to stable or indolent disease course

Differential effects of dual and unihemispheric motor cortex stimulation in older adults

Mittels transcranieller Gleichstromstimulation (tDCS, engl. transcranial direct current stimulation) kann die neuronale Erregbarkeit des primären Motorcortex (M1) nicht-invasiv moduliert werden. Durch anodale Stimulation kommt es zu einer Heraufregulierung der Erregbarkeit des Areals, während eine cathodale Stimulation eine Herabregulierung bewirkt. Neben solchen unihemisphärischen Ansätzen kommt auch die sogenannte bihemisphärische oder „duale“ Stimulation zum Einsatz. Durch diese simultane anodale und cathodale tDCS kann die motorische Lernleistung bei Gesunden sowie die motorische Rehabilitation nach Schlaganfall verbessert werden. Allerdings ist deren Wirkweise nur unzureichend verstanden. Daher untersuchten wir den Einfluss dualer tDCS auf funktionelle Netzwerke (resting state-fMRT), aufgabenspezifische Aktivierungen (fMRT) und deren Zusammenhang mit strukturellen Charakteristika motorischer Bahnen (DTI) bei 20 gesunden älteren Probanden in einer randomisierten, verblindeten, Placebo-kontrollierten Studie mit einem Cross-over Design. Die Teilnehmer wurden in Ruhe und bei Ausführung eines Motortasks in einem 3T-MRT gescannt und gleichzeitig je nach Bedingung dual, anodal oder schein-stimuliert. Mit Hilfe von DTI konnten wir potentielle Funktionsänderungen mit strukturellen Parametern in Verbindung bringen. Die resting-state Analyse zeigte, dass im Vergleich zur Schein-Stimulation sowohl durch duale als auch anodale tDCS die Konnektivität im rechten Hippocampus und dem M1-Areal (kontralateral zur Anode) herabgesetzt wurde, während die Verbindung im linken präfrontalen Cortex gesteigert wurde. Weiterhin verbesserte die duale, allerdings nicht die anodale Stimulation die Verbindungen im linken dorsalen posterioren Cingulum. In den aufgabenspezifischen Aktivierungen im fMRT zeigte sich bei dualer im Vergleich zu anodaler tDCS eine stärkere Aktivierung in beiden M1, wenn die Probanden entweder die linke oder die rechte Hand während der motorischen Aufgaben nutzten. Die entsprechend durch die tDCS hervorgerufenen Veränderungen in der Lateralisation der Aktivierung standen im Verhältnis zum mikrostrukturellen Zustand der motorischen Fasern des Corpus callosum. Zusammenfassend legen unsere Ergebnisse nahe, dass sich der Einfluss von dualer tDCS nicht nur durch rein additive Effekte von anodaler und gleichzeitiger cathodaler Stimulation erklären lässt, sondern durch ein komplexes Regulierungssystem zwischen den Hemisphären und den für die motorische Kontrolle verantwortlichen Bereichen des posterioren Cingulums. Die Kenntnis über die Auswirkungen von dualer tDCS liefert wertvolle Hinweise für weitere Studien zu Therapieansätzen in der Rehabilitation bei Schlaganfallpatienten.Bihemispheric transcranial direct current stimulation (tDCS) is thought to upregulate excitability of the primary motor cortex (M1) using anodal stimulation while concurrently downregulating contralateral M1 using cathodal stimulation. This “dual” tDCS method enhances motor learning in healthy subjects and facilitates motor recovery after stroke. However, its impact on motor system activity and connectivity remains unknown. Therefore, we assessed neural correlates of dual and unihemispheric anodal tDCS effects in 20 healthy older subjects in a randomized, sham-controlled study using a cross-over design. Participants underwent tDCS and simultaneous functional magnetic resonance imaging during a choice reaction time task and at rest. Diffusion tensor imaging (DTI) allowed us to relate potential functional changes to structural parameters. The resting-state analysis demonstrated that, compared with sham, both dual and anodal tDCS decreased connectivity of right hippocampus and M1 (contralateral to the anode position) while increasing connectivity in the left prefrontal cortex. Notably, dual but not anodal tDCS enhanced connectivity of the left dorsal posterior cingulate cortex. Furthermore, dual tDCS yielded stronger activations in bilateral M1 compared with anodal tDCS when participants used either their left or right hand during the motor task. The corresponding tDCS-induced changes in laterality of activations were related to the microstructural status of transcallosal motor fibers. In conclusion, our results suggest that the impact of bihemispheric tDCS cannot be explained by mere add-on effects of anodal and concurrent cathodal stimulation, but rather by complex network modulations involving interhemispheric interactions and areas associated with motor control in the dorsal posterior cingulate cortex

Behavioral/Cognitive Differential Effects of Dual and Unihemispheric Motor Cortex Stimulation in Older Adults

Bihemispheric transcranial direct current stimulation (tDCS) is thought to upregulate excitability of the primary motor cortex (M1) using anodal stimulation while concurrently downregulating contralateral M1 using cathodal stimulation. This "dual" tDCS method enhances motor learning in healthy subjects and facilitates motor recovery after stroke. However, its impact on motor system activity and connectivity remains unknown. Therefore, we assessed neural correlates of dual and unihemispheric anodal tDCS effects in 20 healthy older subjects in a randomized, sham-controlled study using a cross-over design. Participants underwent tDCS and simultaneous functional magnetic resonance imaging during a choice reaction time task and at rest. Diffusion tensor imaging (DTI) allowed us to relate potential functional changes to structural parameters. The resting-state analysis demonstrated that, compared with sham, both dual and anodal tDCS decreased connectivity of right hippocampus and M1 (contralateral to the anode position) while increasing connectivity in the left prefrontal cortex. Notably, dual but not anodal tDCS enhanced connectivity of the left dorsal posterior cingulate cortex. Furthermore, dual tDCS yielded stronger activations in bilateral M1 compared with anodal tDCS when participants used either their left or right hand during the motor task. The corresponding tDCS-induced changes in laterality of activations were related to the microstructural status of transcallosal motor fibers. In conclusion, our results suggest that the impact of bihemispheric tDCS cannot be explained by mere add-on effects of anodal and concurrent cathodal stimulation, but rather by complex network modulations involving interhemispheric interactions and areas associated with motor control in the dorsal posterior cingulate cortex

Transcranial direct current stimulation of the primary motor cortex improves word-retrieval in older adults

Language facilitation by transcranial direct current stimulation (tDCS) in healthy individuals has generated hope that tDCS may also allow improving language impairment after stroke (aphasia). However, current stimulation protocols have yielded variable results and may require identification of residual language cortex using functional magnetic resonance imaging (fMRI), which complicates incorporation into clinical practice. Based on previous behavioral studies that demonstrated improved language processing by motor system pre-activation, the present study assessed whether tDCS administered to the primary motor cortex (M1) can enhance language functions. This proof-of-concept study employed a sham-tDCS controlled, cross-over, within-subject design and assessed the impact of unilateral excitatory (anodal) and bihemispheric (dual) tDCS in 18 healthy older adults during semantic word-retrieval and motor speech tasks. Simultaneous fMRI scrutinized the neural mechanisms underlying tDCS effects. Both active tDCS conditions significantly improved word-retrieval compared to sham-tDCS. The direct comparison of activity elicited by word-retrieval vs. motor-speech trials revealed bilateral frontal activity increases during both anodal- and dual-tDCS compared to sham-tDCS. This effect was driven by more pronounced deactivation of frontal regions during the motor-speech task, while activity during word-retrieval trials was unaffected by the stimulation. No effects were found in M1 and secondary motor regions. Our results show that tDCS administered to M1 can improve word-retrieval in healthy individuals, thereby providing a rationale to explore whether M1-tDCS may offer a novel approach to improve language functions in aphasia. Functional magnetic resonance imaging revealed neural facilitation specifically during motor speech trials, which may have reduced switching costs between the overlapping neural systems for lexical retrieval and speech processing, thereby resulting in improved performance