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Positive Areas (positive + area)

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Medical Sciences100%

Selected Abstracts

Cognitive response control in writer's cramp

EUROPEAN JOURNAL OF NEUROLOGY, Issue 6 2001
D. Berg
Disturbances of the motor and sensory system as well as an alteration of the preparation of movements have been reported to play a role in the pathogenesis of dystonias. However, it is unclear whether higher aspects of cortical , like cognitive , functions are also involved. Recently, the NoGo-anteriorization (NGA) elicited with a visual continuous performance test (CPT) during recording of a 21-channel electroencephalogram has been proposed as an electrophysiological standard-index for cognitive response control. The NGA consists of a more anterior location of the positive area of the brain electrical field associated with the inhibition (NoGo-condition) compared with that of the execution (Go-condition) of a prepared motor response in the CPT. This response control paradigm was applied in 16 patients with writer's cramp (WC) and 14 age matched healthy controls. Topographical analysis of the associated event-related potentials revealed a significant (P < 0.05) NGA effect for both patients and controls. Moreover, patients with WC showed a significantly higher global field power value (P < 0.05) in the Go-condition and a significantly higher difference-amplitude (P < 0.05) in the NoGo-condition. A source location analysis with the low resolution electromagnetic tomography (LORETA) method demonstrated a hypoactivity for the Go-condition in the parietal cortex of the right hemisphere and a hyperactivity in the NoGo-condition in the left parietal cortex in patients with WC compared with healthy controls. These results indicate an altered response control in patients with WC in widespread cortical brain areas and therefore support the hypothesis that the pathogenesis of WC is not restricted to a pure sensory-motor dysfunction. [source]

Expression of Fibroblast Growth Factor-2 in the Nucleus Ambiguus Following Recurrent Laryngeal Nerve Injury in the Rat

THE LARYNGOSCOPE, Issue 12 2000
Tetsuji Sanuki MD
Abstract Objectives To examine fibroblast growth factor-2 (FGF-2) immunoreactivity in the nucleus ambiguus (NA) after three different recurrent laryngeal nerve (RLN) injuries. Study Design Immunohistochemical analysis of FGF-2. Methods Thirty adult rats underwent left-sided RLN crush (group A). The left RLN was transected in groups B (n = 30) and C (n = 30); in group C, both nerve stumps were covered with silicone caps. FGF-2 in the NA was assessed as the ratio of the positive areas on the left (operated [O]) and right (unoperated [U]) sides. The ratio (O/U) was measured 1, 3, 7, 14, and 28 days after the procedure. Three rats underwent left-sided RLN exposure and were killed 7 days later (control). Results Left-sided RLN paralysis occurred until day 28 in group A. In the control group, O/U was approximately 1. In group A, O/U was significantly elevated on day 7; in group B, on days 3, 7, and 14; and in group C, on day 3. O/U in group B was significantly greater than that in group A on days 14 and 28. Maximal FGF-2 immunoreactivity was significantly lower in group C than in groups A and B. Conclusions We demonstrated elevated production of FGF-2 in the NA after RLN injury. This endogenous FGF-2 might contribute to preventing lesion-induced neuronal death. Blockage of axonal regeneration might suppress FGF-2 production in the NA. Further understanding of the roles of FGF-2 after RLN in-jury may contribute to the prevention of neuronal death and facilitation of axonal regeneration. [source]

In search for correlation among markers for limbal stem cells niche

ACTA OPHTHALMOLOGICA, Issue 2009
C CURCIO
Purpose The corneoscleral limbus is known to be the site of corneal epithelial stem cells (SC). Several molecules have been proposed as SC markers but none of them is able to univocally identify them. The aim of this study was to evaluate co-expression of different SC markers in human limbus. Methods In this work five corneoscleral specimens from normal human donor eye-bank eyes (age 52-73 years) were fixed in formalin, divided in 8 segments, embedded in paraffin and examined by immunohistochemistry and immunofluorescence for p63, vimentin (vim), laminin 5, integrin (Int) ,6, Int ,1, Int ,4, connexin 43, ki67 and N-cadherin positivity. We firstly analyzed the distribution and the anatomical structure of limbal crypts in each of the segments. Then we evaluated the percentage of positive areas in the niches. Finally we looked for colocalizations and possible correlations among markers. Results We confirmed a different number of niches among the segments of the same corneoscleral rim. Moreover we observed high variability of niches number among patients which interestingly correlates with the percentage of p63 positivity of niche cells. Confocal microscopy double staining for p63 and vim did not show evident colocalization and vim + cells were seen in the superficial layers rather than in the deep layer of crypts. Int ,1 staining directly correlated with p63 positivity while the remaining proteins appeared variably and widely distributed Conclusion Colocalization was evident at least for two SC markers (Int ,1/p63) within the basal layers, while vim, expressed mainly in the superficial layers could act as late progenitor cell marker. [source]

Plasticity of clonal populations of dedifferentiated adult human articular chondrocytes

ARTHRITIS & RHEUMATISM, Issue 5 2003
Andrea Barbero
Objective To investigate whether adult human articular chondrocytes (AHACs), dedifferentiated by monolayer expansion, can differentiate toward diverse mesenchymal lineages and, if so, whether this ability is regulated by growth factors during monolayer expansion. Methods AHACs were expanded as multiclonal or clonal populations in medium without (control) or with factors enhancing cell dedifferentiation (transforming growth factor ,1, fibroblast growth factor 2, and platelet-derived growth factor type BB [TFP]). Cells were then cultured under conditions promoting chondrogenic, osteogenic, or adipogenic differentiation, and the acquired phenotypes were assessed histologically, biochemically, and by real-time reverse transcriptase,polymerase chain reaction. Results Multiclonal populations of both control- and TFP-expanded AHACs differentiated toward the chondrogenic, osteogenic, and adipogenic lineages. Compared with control-expanded AHACs, TFP-expanded cells displayed enhanced chondrogenic differentiation capacity (2.4-fold higher glycosaminoglycan/DNA content and 2,500-fold higher up-regulation of type II collagen) and osteogenic differentiation capacity (9.4-fold higher increase in alkaline phosphatase activity and 12.4-fold higher up-regulation of bone sialoprotein), but reduced formation of adipocytes (5.2-fold lower oil red O,positive cells/area). Clonal populations of AHACs could be efficiently expanded in TFP, but not in control medium. Most TFP-expanded clones were able to redifferentiate only into chondrocytes (7 of 20) or were unable to differentiate (6 of 20). However, some clones (2 of 20) differentiated toward all of the lineages investigated, thus displaying characteristics of mesenchymal progenitor cells. Conclusion Dedifferentiated AHACs exhibit differentiation plasticity, which is modulated by growth factors used during monolayer expansion and is highly heterogeneous across different clones. Clonal culture of AHACs in the presence of regulatory molecules could lead to the identification of AHAC subpopulations with enhanced cartilage repair capacity. [source]