Biomedical subjects
D Apple
Publications and source records attributed to D Apple.
Evidence of hyaluronic acid and hyaluronic acid binding sites on human corneal endothelium.
A highly specific hyaluronic acid (HA) recognizing protein (HABR) was used to study whether the human corneal endothelium is covered by HA and to quantify the amount. Tritiated high molecular weight HA was used to determine the capacity of the human endothelium to bind exogenous HA. Human corneas were obtained from keratoconus patients having corneal transplantation and from postmortem eyes. The corneas were immersed in a 4% formaldehyde solution containing 1% cetylpyridine chloride for histochemistry, frozen for biochemistry, or used for 3H-HA (Mr 3 x 10(6) binding. For the biochemical determinations, 125I-labeled HABR was used. Tritiated HA was used for the binding experiment. A specific layer of HA covering the endothelial cells of the corneal buttons was demonstrated. The biochemical analysis also revealed the presence of HA. Finally, the human endothelial cells had specific hyaluronic acid binding sites.
Phrenic nerve pacing of the quadriplegic patient.
Phrenic nerve pacing can be used to free a quadriplegic patient from ventilatory dependency. During a 6-year period (1982 to 1988), 23 patients with an age range of 17 to 63 years (mean 31 years) underwent implantation of a phrenic nerve pacemaker because of ventilatory dependency resulting from quadriplegia. Fourteen patients had a unilateral phrenic nerve implant and nine had a bilateral implant. The time from injury to implantation was 12 to 16 weeks. The site of implantation was the cervical phrenic nerve in 13 patients and the thoracic phrenic nerve in 10 patients. During the past 24 months, only a transthoracic approach has been used. The indication for pacing was failure to be weaned from ventilatory support in all patients. Failure to stimulate the phrenic nerve at implantation was noted in three patients, despite preoperative testing indicating an acceptable response. There were no deaths, and minor complications developed in three patients. Follow-up is available in all patients: Eight patients are completely free from the ventilator; nine patients are in markedly improved condition but require the ventilator at night; three patients are in moderately improved condition; and three patients had no response. Three patients required reexploration for component failure from 6 weeks to 18 months after implantation.
[Congenital corneal opacity caused by thickening of Bowman's membrane].
Congenital corneal opacifications are rare, yet their causes are manifold. Only a few cases have been described in which the most striking histopathological feature is a thickening of Bowman's membrane. The authors found an isolated thickening of this membrane in the corneas of a baby who, shortly after birth, presented with corneal opacifications in both eyes. Only a few months after penetrating keratoplasty was performed the condition recurred. Bowman's membrane was found to be thickened in the graft as well.
[Congenital corneal opacity caused by hyperplasia of Bowman's membrane].
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Ocular histopathology in juvenile rheumatoid arthritis.
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The syndrome of inappropriate antidiuretic hormone secretion in multiple sclerosis.
The syndrome of inappropriate secretion of antidiuretic hormone (SIADH) occurred during an excerbation of multiple sclerosis (MS). Rapid symptomatic improvement occurred with correction of the hyponatremia. Although the pathophysiology responsible for development of the SIADH in this patient is unknown, CNS involvement by MS is a likely explanation.
Acute choroidal ischemia as a complication of photocoagulation.
Acute choroidal vascular insufficiency as a complication of photocoagulation has been little noticed. In 17 eyes of 16 patients photocoagulated with either xenon or argon sources for proliferative sickle cell retinopathy, gray lesions of the fundus developed peripheral to the photocoagulation sites. Histologic examination of similar gray lesions produced in monkeys showed necrosis and atrophy of the outer half of the retina. Intense photocoagulation of the human fundus, even with smaller spot sizes, may occlude a choroidal artery, producing separate gray lesions of distinctive shape. The lesions in both the patients and the monkeys progressed to granular hyperpigmentation by two to three weeks after photocoagulation.
Angioid streaks and sickle haemoglobinopathies.
Five patients had angioid streaks associated with sickle cell haemoglobinopathy. Other diseases associated with angioid streaks were ruled out, as was elastic tissue degenegation in sickle cell patients. After studying over 350 patients, we believe the incidence of angioid streaks in sickle cell disease to be between 1 and 2 per cent.
Intraocular injection of gentamicin. Toxic effects of clearance.
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Cataracts induced by the polypeptide antibiotic polymyxin B sulfate.
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Peroxidase diffusion processes in the optic nerve.
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Cushing's syndrome due to ectopic ACTH production by a nasal paraganglioma.
A patient is described with Cushingoid features and a tumor of the paranasal sinuses. Laboratory studies revealed hyperglycemia, hypokalemia, alkalosis, hypercortisolemia, and elevated serum ACTH levels. The cortisol level increased briskly in response to parenteral ACTH, but was only partially suppressed by dexamethasone. Microscopically, the tumor was found to be a paraganglioma containing many neurosecretory granules.. Treatment with methyrapone, o,p'DDD, and irradiation of the tumor resulted in a lasting remission. It is concluded that this unique patient suffered from Cushing's syndrome due to ectopic ACTH production by a paraganglioma of the paranasal sinuses.