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G Blakey

Publications and source records attributed to G Blakey.

4 recordsLinked to original sources
PubMed2003

Modulation of human vestibular-evoked postural responses by alterations in load.

The effects of body loading and unloading on human postural responses elicited by 1 mA bilateral, bipolar galvanic vestibular stimulation (GVS) were investigated. Subjects stood symmetrically, and in separate experiments were either loaded by 16, 33 and 50 % of their body weight with weights attached to the trunk, or unloaded by 10, 20 and 30 % using a whole-body harness that partially lifted the body but was free to translate horizontally. Randomised blocks of stimuli for each loading/unloading condition were compared to a non-loaded control condition. The rate of lateral reaction force development over the period 200-350 ms poststimulus increased in both legs with loading and decreased with unloading. The rate of force development was always larger from the leg on the side of cathodal stimulation. Vertical force responses were equal and opposite in the two legs, increasing on the side of the cathode and decreasing on the side of the anode. The rate of vertical force development over the period 200-350 ms after stimulus onset was increased with loading and decreased with unloading. In the frontal plane, the rate of head and trunk tilt in space was increased and decreased with loading and unloading, respectively. However, the relative rate of head tilt with respect to the trunk was not affected by loading conditions. These experiments provide further evidence that load-related afferent feedback influences the processing of vestibular information for the control of balance.

Adult↗
PubMed1993

Confocal and conventional immunofluorescence and ultrastructural localisation of intracellular strength-giving components of human amniochorion.

Key cytoskeletal polypeptides of human fetal membranes have been localised at subcellular level using confocal and conventional indirect immunofluorescence microscopy. Correlation with electron microscope data has allowed us to examine how cellular compartments of this multilaminar tissue maintain their mechanical integrity until the time of membrane rupture at parturition. Evidence is presented for myofibroblastic characteristics of cells in both the fibroblast and reticular layers which may therefore have tension-generating, position-adjustment and wound-healing roles in the amniochorion. Desmin and vimentin are coexpressed in these cells, but a small localised population of cells in the fibroblast layer contains vimentin alone. An interaction of cytokeratin filaments with nuclei and desmosomes of amniotic epithelium in vivo is demonstrated, indicating that nuclei of cells of ectodermal origin are integrated into a mechanical structure extending throughout the tissue as a whole. Cells of the basal 1 or 2 layers of trophoblast have been shown to have a more extensive and better integrated cytoskeletal organisation than those overlying and forming the boundary with decidua. Structures within the trophoblast, identified previously as degenerate villi, contain cells with intermediate filaments with similar immunofluorescence properties to those of the neighbouring reticular layer and thus may represent papillae that prevent shearing at this interface.

Amnion↗