Search results for "cortical"

Synergistic effects of neurons and astrocytes on the differentiation of brain capillary endothelial cells in culture

2003

Brain capillary endothelial cells form a functional barrier between blood and brain, based on the existence of tight junctions that limit paracellular permeability. Occludin is one of the major transmembrane proteins of tight junctions and its peripheral localization gives indication of tight junction formation. We previously reported that RBE4.B cells (brain capillary endothelial cells), cultured on collagen IV, synthesize occludin and correctly localize it at the cell periphery only when cocultured with neurons. In the present study, we describe a three-cell type-culture system that allowed us to analyze the combined effects of neurons and astrocytes on differentiation of brain capillary …

Spreading Depression Induces Permanent Cell Swelling Under Penumbra Conditions

2000

Background. Spreading depression (SD) is known to go along with temporary breakdown of ion gradients and cell swelling which spontaneously normalizes. Here, the effects of SD at reduced flow conditions as encountered in the ischemic penumbra are examined.

Cortical Hypoactivity or Reduced Efficiency of Cortical Inhibition in Migraine?

2007

Glutamate Enhances Brain Damage from Ischemia and Trauma

1997

The amino acid glutamate is a model agent to demonstrate the significance of neurotoxic mediator compounds in secondary brain damage from trauma, ischemia or other adverse conditions. Intensive research of the role of mediator compounds is clinically worthwile as more specific forms of treatment may emerge for the benefit of afflicted patients. In view of the great number of factors, cytokines, etc., which could play a role, it is mandatory that a mediator function in secondary brain damage is identified according to the stringent requirements established for that purpose. Glutamate has been shown — as is the case for only a few other agents — to meet all the criteria of a mediator of secon…

Progressive femoral cortical and cancellous bone density loss after uncemented tapered-design stem fixation

2010

Background Aseptic implant loosening and periprosthetic bone loss are major problems after total hip arthroplasty (THA). We present an in vivo method of computed tomography (CT) assisted osteodensitometry after THA that differentiates between cortical and cancellous bone density (BD) and area around the femoral component.Method Cortical and cancellous periprosthetic femoral BD (mg CaHA/mL), area (mm2) and contact area between the prothesis and cortical bone were determined prospectively in 31 patients 10 days, 1 year, and 6 years after uncemented THA (mean age at implantation: 55 years) using CT-osteodensitometry.Results 6 years postoperatively, cancellous BD had decreased by as much as 41%…

Influence of Different Rehydration Protocols on Biomechanical Properties of Allogeneic Cortical Bone Plates: A Combined in-vitro/in-vivo Study

2020

Introduction: Allogeneic cortical bone plates (CP) are used for alveolar ridge augmentation. Since CP are freeze-dried and dehydrated during processing, the breaking strength (BS) and the flexibility (FX) are reduced, resulting in a relevant risk for plate fractures during insertion. The aim of this study was to evaluate the influence of rehydration time on the biomechanical properties (BS & FX) of CP in-vitro and in vivo.Material and Methods: 40 CP were randomly divided into four experimental groups. (A) untreated control (n = 10), rehydration for 10 (B), 30 (C) and 60 (D) minutes in 0.9% saline solution (n = 10 each). BS [Newton, N] and FX [mm] (force till fracture and distance of deflect…

Cortical excitability in episodic cluster headache

2014

Background: Cluster headache (CH) is a severe primary headache disorder, whose pathophysiological processes remain largely unknown. Along with central disinhibition of the trigeminal nociceptive system and hypothalamic impairment, a cortical involvement has been supposed. Aim: To evaluate cortical excitability in episodic CH patients by using different paradigms of transcranial magnetic stimulation (TMS). Methods: Twenty-five patients with episodic CH and thirteen healthy subjects underwent an experimental session where we evaluated, in both hemispheres, motor-cortical response to: 1) single-pulse TMS: i.e. motor threshold (MT); input-output (IO) curves and cortical silent period (CSP) and …

Cortical excitability in episodic cluster headache. Neurol Sci

2014

Smadzeņu aktivitāte un volumetriskais ekrāns

2020

Maģistra darbs uzrakstīts angļu valodā uz 32 lappusēm. Tas satur 15 attēlus un ir atsauces uz 37 literatūras avotiem. Strauji attīstoties trīsdimensiju (3D) vizualizācijas tehnoloģijai ir nepieciešams precīzi novērtēt cilvēka spēju pielāgoties tai. Šādos pētījumos plaši tiek izmantots EEG. Pētījuma mērķis bija izpētīt smadzeņu aktivitātes īslaicīgās izmaiņas, skatoties uz volumetriskiem attēliem un salīdzinot ar anaglifa 3D attēlu aplūkošanu. Uzdevums bija noteikt tuvāk esošo apli starp četriem projicētiem apļiem. Smadzeņu aktivitātes signālu reģistrēšanai tika izmantots EEG. Izsaukto potenciālu P300 komponentē darba slodzes ietekmē netika novērotas būtiskas izmaiņas. Būtiskas izmaiņas tika…

Reproducibility of Rolandic beta rhythm modulation in MEG and EEG

2022

The Rolandic beta rhythm, at ∼20 Hz, is generated in the somatosensory and motor cortices and is modulated by motor activity and sensory stimuli, causing a short lasting suppression that is followed by a rebound of the beta rhythm. The rebound reflects inhibitory changes in the primary sensorimotor (SMI) cortex, and thus it has been used as a biomarker to follow the recovery of patients with acute stroke. The longitudinal stability of beta rhythm modulation is a prerequisite for its use in long-term follow-ups. We quantified the reproducibility of beta rhythm modulation in healthy subjects in a 1-year-longitudinal study both for MEG and EEG at T0, 1 month (T1-month, n = 8) and 1 year (T1-ye…