Glaucoma represents the second leading cause of blindness worldwide. While both age and intraocul... more Glaucoma represents the second leading cause of blindness worldwide. While both age and intraocular pressure ͑IOP͒ are wellrecognized risk factors for this disease, the underlying pathologic process involves the accelerated death of retinal ganglion cells ͑RGCs͒ that is associated with progressive loss of vision. The loss of RGCs has been postulated to occur primarily by injury to axons in the optic nerve head ͑ONH͒ due to its anatomic features and the mechanical vulnerability of the lamina cribrosa, the specialized ONH zone comprised of collagen beams that define the channels or pores through which axon bundles exit the eye. Recent advances in multiphoton microscopy using femtosecond lasers that generate second harmonic ͑SH͒ signals from collagen allows for direct optical imaging of the lamina cribrosa. We assess the application of SH generated microscopy ͑SHG͒ to the study of the ONH, and test the general hypothesis that increasing intraocular pressure in the same eye results in the movement of ONH collagen beams leading to distortion of the lamina cribrosa channels and compression of the axon bundles.
The application of second harmonic generation (SHG) microscopy to plant materials has been neglec... more The application of second harmonic generation (SHG) microscopy to plant materials has been neglected hitherto even though it would seem to have promise for identification and characterisation of biologically and commercially important plant polysaccharides. We have found that imaging of cellulose requires rather high laser powers which are above optimal values for live cell imaging. Starch, however is easily imaged by the technique at laser fluences compatible with extended cell viability. This also has useful applications in imaging plant-derived starchy food products. Lignin in plant cell walls shows a strong 3-photon excited fluorescence which may be enhanced by resonance effects.
Density of Meissner's corpuscles in the prepuce as a function of age in patients circumcised ... more Density of Meissner's corpuscles in the prepuce as a function of age in patients circumcised for phimosis and redundant prepuce.
As part of a programme of comparative measurements of P d (diffusional water permeability) the RB... more As part of a programme of comparative measurements of P d (diffusional water permeability) the RBCs (red blood cells) from an aquatic monotreme, platypus (Ornithorhynchus anatinus), and an aquatic reptile, saltwater crocodile (Crocodylus porosus) were studied. The mean diameter of platypus RBCs was estimated by light microscopy and found to be ,6.3 mm. P d was measured by using an Mn 2+-doping 1H NMR (nuclear magnetic resonance) technique. The P d (cm/s) values were relatively low: ,2.1610 23 at 25˚C, 2.5610 23 at 30˚C, 3.4610 23 at 37˚C and 4.5 at 42˚C for the platypus RBCs and ,2.8610 23 at 25˚C, 3.2610 23 at 30˚C, 4.5610 23 at 37˚C and 5.7610 23 at 42˚C for the crocodile RBCs. In parallel with the low water permeability, the E a,d (activation energy of water diffusion) was relatively high, ,35 kJ/mol. These results suggest that ''conventional'' WCPs (water channel proteins), or AQPs (aquaporins), are probably absent from the plasma membranes of RBCs from both the platypus and the saltwater crocodile.
SUMMARYSections of plant tissue cut for the electron microscope sometimes show localized wrinkles... more SUMMARYSections of plant tissue cut for the electron microscope sometimes show localized wrinkles running across the cell wall. These resemble plasmodesmata under low‐power magnification, and appear identical to the ‘densely stained plasmodesmata’ described in some early papers.
Second harmonic generation (SHG) results from molecules being polarized by an external electric f... more Second harmonic generation (SHG) results from molecules being polarized by an external electric field, often provided by an intense laser beam. The polarizability depends on firstly the intrinsic structural properties of the substance and hence the second order nonlinear susceptibility, and secondly the intensity and polarization direction of the incident light. The polarization characteristics of the beam are therefore of
Glaucoma represents the second leading cause of blindness worldwide. While both age and intraocul... more Glaucoma represents the second leading cause of blindness worldwide. While both age and intraocular pressure ͑IOP͒ are wellrecognized risk factors for this disease, the underlying pathologic process involves the accelerated death of retinal ganglion cells ͑RGCs͒ that is associated with progressive loss of vision. The loss of RGCs has been postulated to occur primarily by injury to axons in the optic nerve head ͑ONH͒ due to its anatomic features and the mechanical vulnerability of the lamina cribrosa, the specialized ONH zone comprised of collagen beams that define the channels or pores through which axon bundles exit the eye. Recent advances in multiphoton microscopy using femtosecond lasers that generate second harmonic ͑SH͒ signals from collagen allows for direct optical imaging of the lamina cribrosa. We assess the application of SH generated microscopy ͑SHG͒ to the study of the ONH, and test the general hypothesis that increasing intraocular pressure in the same eye results in the movement of ONH collagen beams leading to distortion of the lamina cribrosa channels and compression of the axon bundles.
The application of second harmonic generation (SHG) microscopy to plant materials has been neglec... more The application of second harmonic generation (SHG) microscopy to plant materials has been neglected hitherto even though it would seem to have promise for identification and characterisation of biologically and commercially important plant polysaccharides. We have found that imaging of cellulose requires rather high laser powers which are above optimal values for live cell imaging. Starch, however is easily imaged by the technique at laser fluences compatible with extended cell viability. This also has useful applications in imaging plant-derived starchy food products. Lignin in plant cell walls shows a strong 3-photon excited fluorescence which may be enhanced by resonance effects.
Density of Meissner's corpuscles in the prepuce as a function of age in patients circumcised ... more Density of Meissner's corpuscles in the prepuce as a function of age in patients circumcised for phimosis and redundant prepuce.
As part of a programme of comparative measurements of P d (diffusional water permeability) the RB... more As part of a programme of comparative measurements of P d (diffusional water permeability) the RBCs (red blood cells) from an aquatic monotreme, platypus (Ornithorhynchus anatinus), and an aquatic reptile, saltwater crocodile (Crocodylus porosus) were studied. The mean diameter of platypus RBCs was estimated by light microscopy and found to be ,6.3 mm. P d was measured by using an Mn 2+-doping 1H NMR (nuclear magnetic resonance) technique. The P d (cm/s) values were relatively low: ,2.1610 23 at 25˚C, 2.5610 23 at 30˚C, 3.4610 23 at 37˚C and 4.5 at 42˚C for the platypus RBCs and ,2.8610 23 at 25˚C, 3.2610 23 at 30˚C, 4.5610 23 at 37˚C and 5.7610 23 at 42˚C for the crocodile RBCs. In parallel with the low water permeability, the E a,d (activation energy of water diffusion) was relatively high, ,35 kJ/mol. These results suggest that ''conventional'' WCPs (water channel proteins), or AQPs (aquaporins), are probably absent from the plasma membranes of RBCs from both the platypus and the saltwater crocodile.
SUMMARYSections of plant tissue cut for the electron microscope sometimes show localized wrinkles... more SUMMARYSections of plant tissue cut for the electron microscope sometimes show localized wrinkles running across the cell wall. These resemble plasmodesmata under low‐power magnification, and appear identical to the ‘densely stained plasmodesmata’ described in some early papers.
Second harmonic generation (SHG) results from molecules being polarized by an external electric f... more Second harmonic generation (SHG) results from molecules being polarized by an external electric field, often provided by an intense laser beam. The polarizability depends on firstly the intrinsic structural properties of the substance and hence the second order nonlinear susceptibility, and secondly the intensity and polarization direction of the incident light. The polarization characteristics of the beam are therefore of
The polarization dependence of the second harmonic emission of purified in-vitro reconstituted fi... more The polarization dependence of the second harmonic emission of purified in-vitro reconstituted fibrils of collagen has been examined. The results confirmed the quasi-hexagonal crystalline structure within the fibrils. Interesting different polarization behaviours were seen between collagen types I and II, which can be utilized as an experimental technique for differentiation.
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Papers by Guy Cox