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1.
Cereb Cortex ; 33(11): 7044-7060, 2023 05 24.
Artículo en Inglés | MEDLINE | ID: mdl-36786655

RESUMEN

Human auditory cortex (AC) organization resembles the core-belt-parabelt organization in nonhuman primates. Previous studies assessed mostly spatial characteristics; however, temporal aspects were little considered so far. We employed co-registration of functional magnetic resonance imaging (fMRI) and magnetoencephalography (MEG) in musicians with and without absolute pitch (AP) to achieve spatial and temporal segregation of human auditory responses. First, individual fMRI activations induced by complex harmonic tones were consistently identified in four distinct regions-of-interest within AC, namely in medial Heschl's gyrus (HG), lateral HG, anterior superior temporal gyrus (STG), and planum temporale (PT). Second, we analyzed the temporal dynamics of individual MEG responses at the location of corresponding fMRI activations. In the AP group, the auditory evoked P2 onset occurred ~25 ms earlier in the right as compared with the left PT and ~15 ms earlier in the right as compared with the left anterior STG. This effect was consistent at the individual level and correlated with AP proficiency. Based on the combined application of MEG and fMRI measurements, we were able for the first time to demonstrate a characteristic temporal hierarchy ("chronotopy") of human auditory regions in relation to specific auditory abilities, reflecting the prediction for serial processing from nonhuman studies.


Asunto(s)
Corteza Auditiva , Animales , Humanos , Corteza Auditiva/diagnóstico por imagen , Corteza Auditiva/fisiología , Potenciales Evocados Auditivos/fisiología , Estimulación Acústica , Mapeo Encefálico/métodos , Magnetoencefalografía/métodos , Imagen por Resonancia Magnética/métodos
2.
Immunology ; 166(1): 121-137, 2022 05.
Artículo en Inglés | MEDLINE | ID: mdl-35196398

RESUMEN

Resting conventional T cells (Tconv) can be distinguished from T regulatory cells (Treg) by the canonical markers FOXP3, CD25 and CD127. However, the expression of these proteins alters after T-cell activation leading to overlap between Tconv and Treg. The objective of this study was to distinguish resting and antigen-responsive T effector (Tconv) and Treg using single-cell technologies. CD4+ Treg and Tconv cells were stimulated with antigen and responsive and non-responsive populations processed for targeted and non-targeted single-cell RNAseq. Machine learning was used to generate a limited set of genes that could distinguish responding and non-responding Treg and Tconv cells and which was used for single-cell multiplex qPCR and to design a flow cytometry panel. Targeted scRNAseq clearly distinguished the four-cell populations. A minimal set of 27 genes was identified by machine learning algorithms to provide discrimination of the four populations at >95% accuracy. In all, 15 of the genes were validated to be differentially expressed by single-cell multiplex qPCR. Discrimination of responding Treg from responding Tconv could be achieved by a flow cytometry strategy that included staining for CD25, CD127, FOXP3, IKZF2, ITGA4, and the novel marker TRIM which was strongly expressed in Tconv and weakly expressed in both responding and non-responding Treg. A minimal set of genes was identified that discriminates responding and non-responding CD4+ Treg and Tconv cells and, which have identified TRIM as a marker to distinguish Treg by flow cytometry.


Asunto(s)
Activación de Linfocitos , Linfocitos T Reguladores , Biomarcadores/metabolismo , Citometría de Flujo , Factores de Transcripción Forkhead/metabolismo , Recuento de Linfocitos
3.
Ann Rheum Dis ; 81(8): 1106-1118, 2022 08.
Artículo en Inglés | MEDLINE | ID: mdl-35418478

RESUMEN

OBJECTIVE: The aim of this study was to assess the extent and the mechanism by which activin A contributes to progressive joint destruction in experimental arthritis and which activin A-expressing cell type is important for disease progression. METHODS: Levels of activin A in synovial tissues were evaluated by immunohistochemistry, cell-specific expression and secretion by PCR and ELISA, respectively. Osteoclast (OC) formation was assessed by tartrat-resistant acid phosphatase (TRAP) staining and activity by resorption assay. Quantitative assessment of joint inflammation and bone destruction was performed by histological and micro-CT analysis. Immunoblotting was applied for evaluation of signalling pathways. RESULTS: In this study, we demonstrate that fibroblast-like synoviocytes (FLS) are the main producers of activin A in arthritic joints. Most significantly, we show for the first time that deficiency of activin A in arthritic FLS (ActßAd/d ColVI-Cre) but not in myeloid cells (ActßAd/d LysM-Cre) reduces OC development in vitro, indicating that activin A promotes osteoclastogenesis in a paracrine manner. Mechanistically, activin A enhanced OC formation and activity by promoting the interaction of activated Smad2 with NFATc1, the key transcription factor of osteoclastogenesis. Consistently, ActßAd/d LysM-Cre hTNFtg mice did not show reduced disease severity, whereas deficiency of activin A in ColVI-Cre-expressing cells such as FLS highly diminished joint destruction reflected by less inflammation and less bone destruction. CONCLUSIONS: The results highly suggest that FLS-derived activin A plays a crucial paracrine role in inflammatory joint destruction and may be a promising target for treating inflammatory disorders associated with OC formation and bone destruction like rheumatoid arthritis.


Asunto(s)
Activinas , Artritis Experimental , Sinoviocitos , Activinas/genética , Animales , Artritis Experimental/patología , Fibroblastos/metabolismo , Inflamación/patología , Ratones , Índice de Severidad de la Enfermedad , Membrana Sinovial/metabolismo , Sinoviocitos/metabolismo
4.
Diabetologia ; 64(5): 1079-1092, 2021 05.
Artículo en Inglés | MEDLINE | ID: mdl-33515070

RESUMEN

AIMS/HYPOTHESIS: Oral administration of antigen can induce immunological tolerance. Insulin is a key autoantigen in childhood type 1 diabetes. Here, oral insulin was given as antigen-specific immunotherapy before the onset of autoimmunity in children from age 6 months to assess its safety and immune response actions on immunity and the gut microbiome. METHODS: A phase I/II randomised controlled trial was performed in a single clinical study centre in Germany. Participants were 44 islet autoantibody-negative children aged 6 months to 2.99 years who had a first-degree relative with type 1 diabetes and a susceptible HLA DR4-DQ8-containing genotype. Children were randomised 1:1 to daily oral insulin (7.5 mg with dose escalation to 67.5 mg) or placebo for 12 months using a web-based computer system. The primary outcome was immune efficacy pre-specified as induction of antibody or T cell responses to insulin and measured in a central treatment-blinded laboratory. RESULTS: Randomisation was performed in 44 children. One child in the placebo group was withdrawn after the first study visit and data from 22 insulin-treated and 21 placebo-treated children were analysed. Oral insulin was well tolerated with no changes in metabolic variables. Immune responses to insulin were observed in children who received both insulin (54.5%) and placebo (66.7%), and the trial did not demonstrate an effect on its primary outcome (p = 0.54). In exploratory analyses, there was preliminary evidence that the immune response and gut microbiome were modified by the INS genotype Among children with the type 1 diabetes-susceptible INS genotype (n = 22), antibody responses to insulin were more frequent in insulin-treated (72.7%) as compared with placebo-treated children (18.2%; p = 0.03). T cell responses to insulin were modified by treatment-independent inflammatory episodes. CONCLUSIONS/INTERPRETATION: The study demonstrated that oral insulin immunotherapy in young genetically at-risk children was safe, but was not associated with an immune response as predefined in the trial primary outcome. Exploratory analyses suggested that antibody responses to oral insulin may occur in children with a susceptible INS genotype, and that inflammatory episodes may promote the activation of insulin-responsive T cells. TRIAL REGISTRATION: Clinicaltrials.gov NCT02547519 FUNDING: The main funding source was the German Center for Diabetes Research (DZD e.V.).


Asunto(s)
Diabetes Mellitus Tipo 1/prevención & control , Inmunoterapia/métodos , Insulina/administración & dosificación , Administración Oral , Formación de Anticuerpos/efectos de los fármacos , Formación de Anticuerpos/genética , Autoanticuerpos/efectos de los fármacos , Autoanticuerpos/genética , Autoinmunidad/efectos de los fármacos , Preescolar , Diabetes Mellitus Tipo 1/genética , Diabetes Mellitus Tipo 1/inmunología , Familia , Femenino , Alemania , Humanos , Lactante , Insulina/inmunología , Masculino , Prevención Primaria/métodos
5.
Blood ; 134(13): 1046-1058, 2019 09 26.
Artículo en Inglés | MEDLINE | ID: mdl-31434705

RESUMEN

Although bone marrow niche cells are essential for hematopoietic stem cell (HSC) maintenance, their interaction in response to stress is not well defined. Here, we used a mouse model of acute thrombocytopenia to investigate the cross talk between HSCs and niche cells during restoration of the thrombocyte pool. This process required membrane-localized stem cell factor (m-SCF) in megakaryocytes, which was regulated, in turn, by vascular endothelial growth factor A (VEGF-A) and platelet-derived growth factor-BB (PDGF-BB). HSCs and multipotent progenitors type 2 (MPP2), but not MPP3/4, were subsequently activated by a dual-receptor tyrosine kinase (RTK)-dependent signaling event, m-SCF/c-Kit and VEGF-A/vascular endothelial growth factor receptor 2 (VEGFR-2), contributing to their selective and early proliferation. Our findings describe a dynamic network of signals in response to the acute loss of a single blood cell type and reveal the important role of 3 RTKs and their ligands in orchestrating the selective activation of hematopoietic stem and progenitor cells (HSPCs) in thrombocytopenia.


Asunto(s)
Células Madre Hematopoyéticas/patología , Proteínas Tirosina Quinasas Receptoras/metabolismo , Transducción de Señal , Trombocitopenia/patología , Enfermedad Aguda , Animales , Becaplermina/metabolismo , Plaquetas/metabolismo , Plaquetas/patología , Células Madre Hematopoyéticas/metabolismo , Ratones Endogámicos C57BL , Proteínas Proto-Oncogénicas c-kit/metabolismo , Trombocitopenia/metabolismo , Factor A de Crecimiento Endotelial Vascular/metabolismo , Receptor 2 de Factores de Crecimiento Endotelial Vascular/metabolismo
6.
Exp Dermatol ; 28(12): 1493-1500, 2019 12.
Artículo en Inglés | MEDLINE | ID: mdl-31419309

RESUMEN

Itch is the commonest skin-related symptom, and sex differences are increasingly recognised as important determinants in stratified medicine, but only little is known about sex differences in itch. Questionnaire-based studies indicated that women perceive itch as more intensive and bothersome in comparison with men. However, data of studies using standardised itch models to objectify sex differences are scarce and inconsistent. To determine sex differences in intensity, skin flares and central processing of histaminergic itch, we compared 15 female and 15 male healthy subjects in a double-blinded, within-subject, placebo-controlled study using a histamine skin prick itch model (histamine 1% applied onto the volar forearm) and functional MRI. We found trends in higher mean itch intensity (0.58 VAS, CI 95% 0.004-1.19, P = .056) and maximum itch intensity (men 3.93 VAS ± 0.39 SD at 3 minutes, women 4.73 VAS ± 0.31 SD at 4 minutes, P = .073) in women paralleled by a trend in a stronger positive correlation between itch intensity and blood oxygen level-dependent (BOLD) activity in brain structures identified during itch in comparison with men (rs in women: .46, P = .08, rs in men: .07, P = .79). The erythema and wheal following histamine skin pricking were (non-significantly) larger in men, indicating that higher mean itch intensities on the right volar forearm in women may not be explained by more intense flares. The comparison of the activation patterns between the sexes revealed increased activity in men compared to women in the left middle temporal gyrus (temporooccipital part)/lateral occipital cortex. Thus, our findings indicate that histaminergic itch perception and central itch processing differ between the sexes under standardised conditions.


Asunto(s)
Encéfalo/fisiopatología , Prurito/fisiopatología , Caracteres Sexuales , Piel/fisiopatología , Adulto , Encéfalo/diagnóstico por imagen , Femenino , Histamina , Humanos , Imagen por Resonancia Magnética , Masculino , Proyectos Piloto , Prurito/diagnóstico por imagen , Adulto Joven
7.
Clin Immunol ; 188: 23-30, 2018 03.
Artículo en Inglés | MEDLINE | ID: mdl-29229565

RESUMEN

The phenotype of autoreactive T cells in type 1 diabetes is described as Th1, Th17 and/or Th21, but is largely uncharacterized. We combined multi-parameter cytokine profiling and proliferation, and identified GM-CSF producing cells as a component of the response to beta cell autoantigens proinsulin and GAD65. Overall cytokine profiles of CD4+ T cell were not altered in type 1 diabetes. In contrast, patients with recent onset type 1 diabetes had increased frequencies of proinsulin-responsive CD4+CD45RA- T cells producing GM-CSF (p=0.002), IFNγ (p=0.004), IL-17A (p=0.008), IL-21 (p=0.011), and IL-22 (p=0.007), and GAD65-responsive CD4+CD45RA- T cells producing IL-21 (p=0.039). CD4+ T cells with a GM-CSF+IFNγ-IL-17A-IL-21-IL-22- phenotype were increased in patients for responses to both proinsulin (p=0.006) and GAD65 (p=0.037). GM-CSF producing T cells are a novel phenotype in the repertoire of T helper cells in type 1 diabetes and consolidate a Th1/Th17 pro-inflammatory pathogenesis in the disease.


Asunto(s)
Linfocitos T CD4-Positivos/inmunología , Citocinas/inmunología , Diabetes Mellitus Tipo 1/inmunología , Factor Estimulante de Colonias de Granulocitos y Macrófagos/inmunología , Autoantígenos/inmunología , Linfocitos T CD4-Positivos/metabolismo , Células Cultivadas , Citocinas/metabolismo , Diabetes Mellitus Tipo 1/metabolismo , Expresión Génica/inmunología , Glutamato Descarboxilasa , Factor Estimulante de Colonias de Granulocitos y Macrófagos/biosíntesis , Humanos , Proinsulina/inmunología , Proinsulina/metabolismo , Células TH1/inmunología , Células TH1/metabolismo , Células Th17/inmunología , Células Th17/metabolismo
8.
J Biol Chem ; 291(1): 103-9, 2016 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-26553871

RESUMEN

Inflammasomes are high molecular weight protein complexes that assemble in the cytosol upon pathogen encounter. This results in caspase-1-dependent pro-inflammatory cytokine maturation, as well as a special type of cell death, known as pyroptosis. The Nlrp3 inflammasome plays a pivotal role in pathogen defense, but at the same time, its activity has also been implicated in many common sterile inflammatory conditions. To this effect, several studies have identified Nlrp3 inflammasome engagement in a number of common human diseases such as atherosclerosis, type 2 diabetes, Alzheimer disease, or gout. Although it has been shown that known Nlrp3 stimuli converge on potassium ion efflux upstream of Nlrp3 activation, the exact molecular mechanism of Nlrp3 activation remains elusive. Here, we describe a genome-wide CRISPR/Cas9 screen in immortalized mouse macrophages aiming at the unbiased identification of gene products involved in Nlrp3 inflammasome activation. We employed a FACS-based screen for Nlrp3-dependent cell death, using the ionophoric compound nigericin as a potassium efflux-inducing stimulus. Using a genome-wide guide RNA (gRNA) library, we found that targeting Nek7 rescued macrophages from nigericin-induced lethality. Subsequent studies revealed that murine macrophages deficient in Nek7 displayed a largely blunted Nlrp3 inflammasome response, whereas Aim2-mediated inflammasome activation proved to be fully intact. Although the mechanism of Nek7 functioning upstream of Nlrp3 yet remains elusive, these studies provide a first genetic handle of a component that specifically functions upstream of Nlrp3.


Asunto(s)
Proteínas Portadoras/metabolismo , Repeticiones Palindrómicas Cortas Agrupadas y Regularmente Espaciadas/genética , Genoma , Inflamasomas/metabolismo , Proteínas Serina-Treonina Quinasas/metabolismo , Animales , Células HEK293 , Humanos , Ratones , Quinasas Relacionadas con NIMA , Proteína con Dominio Pirina 3 de la Familia NLR , Transducción de Señal
9.
Neurobiol Learn Mem ; 141: 53-59, 2017 May.
Artículo en Inglés | MEDLINE | ID: mdl-28347876

RESUMEN

The parietal lobe is important for successful recognition memory, but its role is not yet fully understood. We investigated the parietal lobes' contribution to immediate paired-associate memory and delayed item-recognition memory separately for hits (targets) and correct rejections (distractors). We compared the behavioral performance of 56 patients with known parietal and medial temporal lobe dysfunction (i.e. early Alzheimer's Disease) to 56 healthy control participants in an immediate paired and delayed single item object memory task. Additionally, we performed voxel-based morphometry analyses to investigate the functional-neuroanatomic relationships between performance and voxel-based estimates of atrophy in whole-brain analyses. Behaviorally, all participants performed better identifying targets than rejecting distractors. The voxel-based morphometry analyses associated atrophy in the right ventral parietal cortex with fewer correct responses to familiar items (i.e. hits) in the immediate and delayed conditions. Additionally, medial temporal lobe integrity correlated with better performance in rejecting distractors, but not in identifying targets, in the immediate paired-associate task. Our findings suggest that the parietal lobe critically supports successful immediate and delayed target recognition memory, and that the ventral aspect of the parietal cortex and the medial temporal lobe may have complementary preferences for identifying targets and rejecting distractors, respectively, during recognition memory.


Asunto(s)
Amnesia/fisiopatología , Disfunción Cognitiva/fisiopatología , Lóbulo Parietal/fisiología , Reconocimiento en Psicología/fisiología , Anciano , Anciano de 80 o más Años , Amnesia/diagnóstico por imagen , Mapeo Encefálico , Disfunción Cognitiva/diagnóstico por imagen , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Imagen por Resonancia Magnética , Masculino , Pruebas Neuropsicológicas , Lóbulo Parietal/diagnóstico por imagen
10.
Exp Dermatol ; 26(10): 845-853, 2017 10.
Artículo en Inglés | MEDLINE | ID: mdl-28109199

RESUMEN

The skin and brain have a close bi-directional anatomical and functional connection. Historically, the skin-brain axis and the brain-skin axis have been well described. However, brain function in this context has only recently been demystified with the introduction of functional neuroimaging in dermatology. Functional neuroimaging, especially functional magnetic resonance imaging (fMRI), allows indirect visualisation of brain function. This review looks back to the beginnings of functional neuroimaging in dermatology, summarises the currently available dermatology-related fMRI studies and discusses the potential future role of fMRI as a stratifying tool in clinical dermatology and in the development of novel therapies. According to the main body of research made in this field, the focus is placed on experimental itch studies, which described the brain structures involved in itch processing, the regulation of the scratch response, contagious itch and itch suppression.


Asunto(s)
Encéfalo/diagnóstico por imagen , Neuroimagen Funcional , Imagen por Resonancia Magnética , Prurito/tratamiento farmacológico , Prurito/fisiopatología , Encéfalo/fisiología , Delirio de Parasitosis/diagnóstico por imagen , Humanos , Prurito/psicología , Psoriasis/diagnóstico por imagen , Psoriasis/psicología , Fenómenos Fisiológicos de la Piel
11.
Eur Radiol ; 27(1): 267-278, 2017 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-27193934

RESUMEN

OBJECTIVES: To analyse the long-term feasibility and limitations of presurgical fMRI in a cohort of tumour and epilepsy patients with different MR-scanners at 1.5 and 3.0 T. METHODS: Four hundred and ninety-one consecutive patients undergoing presurgical fMRI between 2000 and 2012 on five different MR-scanners using established paradigms and semi-automated data processing were included. Success rates of task performance and BOLD-activation were determined for motor and somatosensory somatotopic mapping and language localisation. Procedural success, failures and imaging artifacts were analysed. MR-field strengths were compared. RESULTS: Two thousand three hundred fifteen of 2348 (98.6 %) attempted paradigms (1033 motor, 1220 speech, 95 somatosensory) were successfully performed. 100 paradigms (4.3 %) were repetition runs. 23 speech, 6 motor and 2 sensory paradigms failed for non-compliance and technical issues. Most language paradigm failures were noted in overt sentence generation. Average significant BOLD-activation was higher for motor than language paradigms (95.8 vs. 81.6 %). Most language paradigms showed significantly higher activation rates at 3 T compared to 1.5 T, whereas no significant difference was found for motor paradigms. CONCLUSIONS: fMRI proved very robust for the presurgical localisation of the different motor and somatosensory body representations, as well as Broca's and Wernicke's language areas across different MR-scanners at 1.5 and 3.0 T over 13 years. KEY POINTS: • Standardised presurgical motor and language fMRI is robust across various MRI platforms. • Motor fMRI is less dependent on field strength than language fMRI. • fMRI task failures are relatively low and are reduced by paradigm repetition.


Asunto(s)
Mapeo Encefálico/métodos , Neoplasias Encefálicas/cirugía , Epilepsia/cirugía , Lenguaje , Actividad Motora/fisiología , Corteza Somatosensorial/fisiopatología , Adolescente , Adulto , Artefactos , Neoplasias Encefálicas/patología , Neoplasias Encefálicas/fisiopatología , Epilepsia/patología , Epilepsia/fisiopatología , Estudios de Factibilidad , Femenino , Humanos , Imagen por Resonancia Magnética/métodos , Masculino , Persona de Mediana Edad , Cuidados Preoperatorios/métodos , Estudios Retrospectivos , Adulto Joven
12.
BMC Anesthesiol ; 16(1): 118, 2016 11 25.
Artículo en Inglés | MEDLINE | ID: mdl-27884107

RESUMEN

BACKGROUND: Cognitive decline is frequently observed in elderly patients after major surgery. The pathophysiology of postoperative cognitive dysfunction (POCD) remains unclear. The aim of our investigation is to identify potential associations between brain volume change and POCD in elderly patients undergoing major surgery. METHODS: This is a prospective observational cohort study approved by the regional ethics board. We intend to compare specific brain volumes (hippocampus, lateral ventricle, total grey matter volume, regional cortical thickness) on magnetic resonance imaging and cognitive functions determined by a neuropsychological assessment battery in 70 study participants aged ≥65 years before and 3 and 12 months after major noncardiac surgery. Thirty volunteers will be included as matched nonsurgical controls. The primary endpoint of the study is the change in hippocampal volume over time in patients with and without POCD. The secondary endpoint is the correlation between the change in cerebral volume and cognitive function. We will follow the STROBE guidelines for reporting the results of observational studies. DISCUSSION: We hypothesize that surgery under general anesthesia is associated with a loss of cerebral grey matter, and that the degree of postoperative cognitive dysfunction correlates with the extent of atrophy in areas of the brain that are relevant for cognitive functions. The validation of reproducible anatomical biomarkers, such as the specific brain volumes examined in our cohort, may serve to evaluate the effect of preventive strategies and treatment interventions for POCD in follow-up studies. TRIAL REGISTRATION: Clinicaltrials.gov NCT02045004 . Registered 22 January 2014. Kofam.ch SNCTP000001751. Registered 21 April 2016 (retrospectively registered).


Asunto(s)
Protocolos Clínicos , Trastornos del Conocimiento/patología , Sustancia Gris/patología , Complicaciones Posoperatorias/patología , Anciano , Estudios de Casos y Controles , Corteza Cerebral/patología , Femenino , Hipocampo/patología , Humanos , Ventrículos Laterales/patología , Imagen por Resonancia Magnética , Masculino , Neuroimagen , Pruebas Neuropsicológicas , Estudios Prospectivos
13.
Neuroimage ; 108: 87-94, 2015 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-25536494

RESUMEN

Different pathological processes like demyelination and axonal loss can alter the magnetisation transfer ratio (MTR) in brain tissue. The standard method to measure this effect is to scan the respective tissue twice, one with and one without a specific saturation pulse. A major drawback of this technique based on spoiled gradient echo (GRE) sequences relates to its long acquisition time due to the saturation pulses. Recently, an alternative concept for MT imaging based on balanced steady state free precession (bSSFP) has been proposed. Modification of the duration of the radiofrequency pulses for imaging allows scanning MT sensitive and non-sensitive images. The steady-state character of bSSFP with high intrinsic signal-to-noise ratio (SNR) allows three-dimensional (3D) whole brain MTR at high spatial resolution within short and thus clinically feasible acquisition times. In the present study, both bSSFP-MT and 2D GRE-MT imaging were used in a cohort of 31 patients with multiple sclerosis (MS) to characterize different normal appearing (NA) and pathological brain structures. Under the constraint of identical SNR and scan time, a 3.4 times higher voxel size could be achieved with bSSFP. This increased resolution allowed a more accurate delineation of the different brain structures, especially of cortex, hippocampus and MS lesions. In a multiple linear regression model, we found an association between MTR of cortical lesions and a clinical measure of disability (r= -0.407, p=0.035) in the bSSFP dataset only. The different relaxation weighting of the base images (T2/T1 in bSSFP, proton density in GRE) had no effects besides a larger spreading of the MTR values of the different NA structures. This was demonstrated by the nearly perfect linearity between the NA matter MTR of both techniques as well as in the absolute MTR differences between NA matter and the respective lesions.


Asunto(s)
Interpretación de Imagen Asistida por Computador/métodos , Imagenología Tridimensional/métodos , Imagen por Resonancia Magnética/métodos , Esclerosis Múltiple Recurrente-Remitente/patología , Neuroimagen/métodos , Adulto , Anciano , Encéfalo/patología , Femenino , Humanos , Masculino , Persona de Mediana Edad
15.
Cereb Cortex ; 24(5): 1127-37, 2014 May.
Artículo en Inglés | MEDLINE | ID: mdl-23302811

RESUMEN

Absolute pitch (AP) perception is the auditory ability to effortlessly recognize the pitch of any given tone without external reference. To study the neural substrates of this rare phenomenon, we developed a novel behavioral test, which excludes memory-based interval recognition and permits quantification of AP proficiency independently of relative pitch cues. AP- and non-AP-possessing musicians were studied with morphological and functional magnetic resonance imaging (fMRI) and magnetoencephalography. Gray matter volume of the right Heschl's gyrus (HG) was highly correlated with AP proficiency. Right-hemispheric auditory evoked fields were increased in the AP group. fMRI revealed an AP-dependent network of right planum temporale, secondary somatosensory, and premotor cortices, as well as left-hemispheric "Broca's" area. We propose the right HG as an anatomical marker of AP and suggest that a right-hemispheric network mediates AP "perception," whereas pitch "labeling" takes place in the left hemisphere.


Asunto(s)
Corteza Auditiva/anatomía & histología , Corteza Auditiva/fisiología , Potenciales Evocados Auditivos/fisiología , Lateralidad Funcional/fisiología , Percepción de la Altura Tonal/fisiología , Estimulación Acústica , Adulto , Mapeo Encefálico , Electroencefalografía , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Imagen por Resonancia Magnética , Magnetoencefalografía , Masculino , Persona de Mediana Edad , Oxígeno/sangre , Psicoacústica , Tiempo de Reacción/fisiología , Análisis de Regresión , Adulto Joven
16.
Sci Rep ; 14(1): 8109, 2024 04 06.
Artículo en Inglés | MEDLINE | ID: mdl-38582757

RESUMEN

Bone resorption is highly dependent on the dynamic rearrangement of the osteoclast actin cytoskeleton to allow formation of actin rings and a functional ruffled border. Hem1 is a hematopoietic-specific subunit of the WAVE-complex which regulates actin polymerization and is crucial for lamellipodia formation in hematopoietic cell types. However, its role in osteoclast differentiation and function is still unknown. Here, we show that although the absence of Hem1 promotes osteoclastogenesis, the ability of Hem1-/- osteoclasts to degrade bone was severely impaired. Global as well as osteoclast-specific deletion of Hem1 in vivo revealed increased femoral trabecular bone mass despite elevated numbers of osteoclasts in vivo. We found that the resorption defect derived from the morphological distortion of the actin-rich sealing zone and ruffled border deformation in Hem1-deficient osteoclasts leading to impaired vesicle transport and increased intracellular acidification. Collectively, our data identify Hem1 as a yet unknown key player in bone remodeling by regulating ruffled border formation and consequently the resorptive capacity of osteoclasts.


Asunto(s)
Resorción Ósea , Osteoclastos , Humanos , Osteoclastos/metabolismo , Actinas/metabolismo , Resorción Ósea/metabolismo , Huesos/metabolismo , Osteogénesis
17.
Glia ; 61(7): 1122-33, 2013 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-23633299

RESUMEN

Sialic-acid-binding immunoglobulin-like lectin-h (Siglec-h) is a recently identified mouse-specific CD33-related Siglec that signals via DAP12/TYROBP. Expression of Siglec-h has been observed on plasmacytoid dendritic cells and microglia, but the ligand and the function of Siglec-h remained elusive. Here, we demonstrate gene transcription and protein expression of Siglec-h by mouse microglia after interferon-γ treatment or polarization into a M1-subtype. Microglial Siglec-h acted as phagocytosis receptor since targeting of microsphere beads to Siglec-h triggered their uptake into the microglia. The extracellular domain of Siglec-h protein bound to mouse glioma lines, but not to astrocytes or other normal mouse cells. Microglial cells stimulated to express Siglec-h engulfed intact glioma cells without prior induction of apoptosis and slightly reduced glioma cell number in culture. Phagocytosis of glioma cells by activated microglia was dependent on Siglec-h and its adapter molecule DAP12. Thus, data show that M1-polarized microglial cells can engulf glioma cells via a DAP12-mediated Siglec-h dependent mechanism.


Asunto(s)
Glioma/metabolismo , Neuroglía/metabolismo , Lectina 1 Similar a Ig de Unión al Ácido Siálico/metabolismo , Animales , Animales Recién Nacidos , Anexina A5/metabolismo , Apoptosis/genética , Apoptosis/fisiología , Encéfalo/citología , Polaridad Celular/efectos de los fármacos , Polaridad Celular/genética , Células Cultivadas , Técnicas de Cocultivo , Cricetulus , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Regulación Neoplásica de la Expresión Génica/genética , Glioma/patología , Humanos , Interferón gamma/farmacología , Ratones , Ratones Endogámicos C57BL , Invasividad Neoplásica/genética , Neuroglía/efectos de los fármacos , Fagocitosis/fisiología , Unión Proteica/efectos de los fármacos , Unión Proteica/genética , Lectina 1 Similar a Ig de Unión al Ácido Siálico/genética
18.
Brain Sci ; 13(6)2023 May 24.
Artículo en Inglés | MEDLINE | ID: mdl-37371329

RESUMEN

Objective: Evaluation of interrater reliability for manual segmentation of brain structures that are affected first by neurofibrillary tau pathology in Alzheimer's disease. Method: Medial perirhinal cortex, lateral perirhinal cortex, and entorhinal cortex were manually segmented by two raters on structural magnetic resonance images of 44 adults (20 men; mean age = 69.2 ± 10.4 years). Intraclass correlation coefficients (ICC) of cortical thickness and volumes were calculated. Results: Very high ICC values of manual segmentation for the cortical thickness of all regions (0.953-0.986) and consistently lower ICC values for volume estimates of the medial and lateral perirhinal cortex (0.705-0.874). Conclusions: The applied manual segmentation protocol allows different raters to achieve remarkably similar cortical thickness estimates for regions of the parahippocampal gyrus. In addition, the results suggest a preference for cortical thickness over volume as a reliable measure of atrophy, especially for regions affected by collateral sulcus variability (i.e., medial and lateral perirhinal cortex). The results provide a basis for future automated segmentation and collection of normative data.

19.
Neuropsychology ; 37(7): 717-740, 2023 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-36201797

RESUMEN

OBJECTIVE: We aimed to develop a measure to specifically assess the functioning of the perirhinal cortex (PRC), a brain structure affected very early in Alzheimer's disease (AD) pathology. In this novel task, participants were shown arrays of six complex figures and had to identify the "odd-one." METHOD: The pilot study included 50 normal controls (NCs) and 50 patients in very early stages of AD. Participants completed the task and received MRI scanning. Best differentiating items were determined and applied in a validation study including 25 NCs, 27 early-stage AD patients, and 26 patients with major depression. Logistic regression models investigated if task performance predicted group membership. Task performance was then related to whole-brain gray matter integrity. As proof of concept, cortical thickness values of four regions of interest (ROIs; e.g., medial PRC and entorhinal cortex [ERC]) were compared between the groups. The associations of task performance and cortical thickness of the ROIs were investigated using linear models. RESULTS: Task performance showed good discriminative ability between early-stage AD patients and NCs. Whole-brain analyses revealed four significant clusters (p < .001) with peak voxels in parahippocampal regions including PRC and ERC. ROI analyses showed distinctly reduced cortical thickness in the AD group compared to both other groups in the medial PRC and ERC (p ≤ .001). Task performance modeled by ROI cortical thickness did not achieve significant results. CONCLUSION: Although further validation is needed, especially with age-matched participant groups, these findings indicate that the task detects early cognitive impairment related to AD. (PsycInfo Database Record (c) 2023 APA, all rights reserved).


Asunto(s)
Enfermedad de Alzheimer , Disfunción Cognitiva , Humanos , Enfermedad de Alzheimer/diagnóstico por imagen , Enfermedad de Alzheimer/patología , Proyectos Piloto , Corteza Entorrinal/patología , Imagen por Resonancia Magnética/métodos , Encéfalo/diagnóstico por imagen , Encéfalo/patología , Disfunción Cognitiva/patología
20.
Front Aging Neurosci ; 14: 807971, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35401149

RESUMEN

Background: Professional musicians are a model population for exploring basic auditory function, sensorimotor and multisensory integration, and training-induced neuroplasticity. The brain of musicians exhibits distinct structural and functional cortical features; however, little is known about how these features evolve during aging. This multiparametric study aimed to examine the functional and structural neural correlates of lifelong musical practice in elderly professional musicians. Methods: Sixteen young musicians, 16 elderly musicians (age >70), and 15 elderly non-musicians participated in the study. We assessed gray matter metrics at the whole-brain and region of interest (ROI) levels using high-resolution magnetic resonance imaging (MRI) with the Freesurfer automatic segmentation and reconstruction pipeline. We used BrainVoyager semiautomated segmentation to explore individual auditory cortex morphotypes. Furthermore, we evaluated functional blood oxygenation level-dependent (BOLD) activations in auditory and non-auditory regions by functional MRI (fMRI) with an attentive tone-listening task. Finally, we performed discriminant function analyses based on structural and functional ROIs. Results: A general reduction of gray matter metrics distinguished the elderly from the young subjects at the whole-brain level, corresponding to widespread natural brain atrophy. Age- and musicianship-dependent structural correlations revealed group-specific differences in several clusters including superior, middle, and inferior frontal as well as perirolandic areas. In addition, the elderly musicians exhibited increased gyrification of auditory cortex like the young musicians. During fMRI, the elderly non-musicians activated predominantly auditory regions, whereas the elderly musicians co-activated a much broader network of auditory association areas, primary and secondary motor areas, and prefrontal and parietal regions like, albeit weaker, the young musicians. Also, group-specific age- and musicianship-dependent functional correlations were observed in the frontal and parietal regions. Moreover, discriminant function analysis could separate groups with high accuracy based on a set of specific structural and functional, mainly temporal and occipital, ROIs. Conclusion: In conclusion, despite naturally occurring senescence, the elderly musicians maintained musicianship-specific structural and functional cortical features. The identified structural and functional brain regions, discriminating elderly musicians from non-musicians, might be of relevance for the aging musicians' brain. To what extent lifelong musical activity may have a neuroprotective impact needs to be addressed further in larger longitudinal studies.

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