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Biomedical subjects

C M Calthorpe

Publications and source records attributed to C M Calthorpe.

4 recordsLinked to original sources

Chemoattractants produced by ocular cells induce trabecular meshwork cell migration.

Media conditioned by bovine corneal endothelium and scleral fibroblasts were found to induce the migration of bovine trabecular meshwork cells. The migrational activity had both chemokinetic (stimulated random motion) and chemotactic (directional migration) components. That produced by corneal endothelial cells had a markedly more potent effect. The relevance of these in vitro studies is discussed. Biochemically stimulated migration and loss of meshwork cells may be involved in the pathogenesis of glaucoma.

Animals↗

Fibronectin induces migration of bovine trabecular meshwork cells in vitro.

The migration of cultured bovine trabecular meshwork cells in response to fibronectin was studied using a 48-well migration chamber. Fibronectin was shown to be a potent chemoattractant for these cells, with a dose optimum of 30 micrograms ml-1. At this dose, the number of migrated cells was approximately 12 times that of the control, which was serum-free medium. Analysis of the migratory response revealed it to be mainly a chemokinesis, but chemotaxis was a substantial component. Electron microscopy demonstrated that adhesion and spreading of cells on the surface of the pore-containing membrane are necessary prerequisites to their migration through a pore. Microspikes are abundant during the movement of cellular processes into and through the pores. The migrated cells are extremely thin with a large surface area, but despite this phenotypic alteration the ultrastructure of migrated cells is unchanged.

Animals↗

The pattern electroretinogram (PERG) in ocular hypertension and glaucoma.

Studies of normal subjects and of patients with optic nerve disorders suggest that one of the components of the pattern electroretinogram (PERG), the second negative wave, is related to optic nerve function and appears to be diminished even when the condition is relatively mild, with little alteration of visual acuity. It is known that significant loss of nerve fibers may occur prior to the development of visual field loss. We have investigated the PERGs of a group of subjects with early glaucoma and ocular hypertension, comparing them with normal subjects, and have found a selective reduction in the second negative wave in patients with evidence of optic nerve dysfunction. The PERG may prove helpful in discriminating those patients with ocular hypertension who are destined to develop visual field loss unless medical or surgical therapy were to be employed.

Adolescent↗

Posterior scleritis: a clinical and histological survey.

The clinical course of 47 patients with posterior scleritis is reviewed. Though clinical presentation varied widely, 73% of the patients presented with a visual acuity of 6/18 or less. Because the posterior scleritis was not always associated with pain or with anterior scleritis, the diagnosis was often not considered when the patient was first seen. The most common findings in the fundus were disc swelling, retinal detachment, and macular oedema and the most useful investigation was B scan ultrasound. No common aetiology was found, although 60% had a systemic disorder which was accompanied by a vasculitis. Those who were diagnosed and treated with the minimum delay had the most satisfactory visual outcome. However, there appears to be a group of patients with no underlying systemic disease who fail to respond to intensive therapy, and lose vision. A new sub-group of West Indians with the disease is described. The histopathology of 7 cases confirmed the presence of scleral vasculitis of the vessels in and around the sclera in all the specimens. Other significant findings include inflammatory swelling and focal loss of pigment epithelium together with choroidal vascular closure. This could account for the fluorescein angiographic findings.

Adolescent↗