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Biomedical subjects

T Topping

Publications and source records attributed to T Topping.

4 recordsLinked to original sources

Retinal pigment epithelial tears associated with trauma.

Two previously healthy patients, a 66-year-old man with blunt trauma to the right eye, and a 28-year-old man with head trauma from a motorcycle accident, were observed to have parafoveal retinal pigment epithelial tears after injury. In both patients, fluorescein angiography demonstrated mottled window defects in the areas of the tears, and blocked fluorescence in the areas of the rolled-up pigment epithelium. Neither eye had evidence of pigment epithelial detachments. We hypothesize that this unusual phenomenon is caused by an acute tractional force oriented tangentially to the macular plane, the result of a rapid spherically expansile deformation of the globe during trauma.

Accidents, Traffic↗

Evidence that trypsin digestion exposes a channel in the sarcoplasmic reticulum membrane.

We present evidence that proteolytic digestion of sarcoplasmic reticulum membranes with trypsin exposes an ionophore that is capable of translocating calcium across the membrane of preloaded vesicles. Net transport of calcium appears to stop when the chemical potential of the ion on both sides of the membrane is equal. The temperature coefficient of steady-state leakage suggests that the ionophore is of the channel or pore type. We suggest that tryptic digestion exposes a channel in sarcoplasmic reticulum membranes through which calcium, and perhaps other ions as well, can diffuse down concentration gradients.

Adenosine Triphosphate↗

An improved method for practice vitrectomy.

Practice is essential for acquiring the skills necessary for the delicate technique of pars plana vitrectomy. An improved animal model is presented for the beginning surgeon and the assistant to learn basic as well as advanced vitrectomy techniques. A stepwise scheme progressing from simple vitrectomy in the phakic rabbit eye to complicated situations is introduced. Fluorescein staining helps in visualization of the normal vitreous. Double perforating injuries are created to simulate complicated vitreoretinal problems. Methods for learning manipulations with two instruments in the eye are described.

Animals↗