Search PubMed⌕ Search

Biomedical subjects

J C Merritt

Publications and source records attributed to J C Merritt.

45 records · Page 3Linked to original sources
PubMedDate not supplied

Topical delta 9-tetrahydrocannabinol and aqueous dynamics in glaucoma.

Systemic delta 9-tetrahydrocannabinol (THC), administered either by smoking marihuana or as synthetic THC in soft gelatin capsules, lowers ocular tension in various glaucomas, but at the expense of significant decreases in systolic blood pressure. Topical THC in light mineral oil vehicles, though effective in laboratory animals, was not shown effective in 0.05 and 0.1% topical solutions when administered to six subjects with primary open-angle glaucoma in a randomized, balanced, double-masked protocol. Light mineral oil, which has an affinity for corneal epithelium, is an optimum vehicle for administering drugs whose mechanisms of action are systemic rather than local within the eye. Further glaucoma research should therefore proceed with marihuanas containing insignificant levels of THC (less than 0.4%) and with various local delivery systems of the ocular-active cannabinoid found in Cannabis sativa.

Aged↗
PubMedDate not supplied

Effect of mydriatics on blood pressure in premature infants.

Systolic blood pressure (SBP) was measured by doppler methods at 5, 15, 30, 45, and 60 minutes in 52 premature infants after triple instillation of aqueous phenylephrine 2.5% and tropicamide 1.0%. Systolic blood pressures were insignificantly increased 3.9 +/- 2.0 mm Hg (mean +/- S.E.) at 15 minutes when compared with controls matched for initial blood pressure, birth weights and age at examination. Though a 964 gm, 28-week Caucasian male with retinopathy of prematurity had been uneventfully dilated, pupillary dilatation one week later with triple instillations of phenylephrine 2.5% and tropicamide 1.07% was accompanied by an acute increase in systolic blood pressure to 108 mm Hg at 15 minutes, which remained elevated for 150 minutes. A new lower dose, single instillation mydriatic became available whose final concentration was phenylephrine 2.5%, tropicamide 0.5% and cyclogyl 0.5%. A single drop was found to produce mydriasis equal to the triple instillation regime. The single administration produced no significant effect on systolic blood pressure in 30 low birth weight infants (birth weight less than 1750 gm) when compared with balanced salt solution (placebo) in a randomized, double--masked study. Mechanisms of acute hypertension after topical mydriasis are discussed.

Blood Pressure↗
PubMedDate not supplied

Bilateral macular infaction in SS disease.

A 10-year-old Afro-American female with SS disease presented with a history of painless loss of vision (RE) of 26 hours duration. Sequential fluorescein angiography revealed bilateral parafoveal occlusions and evidence of prior vaso-occlusions in each eye. Initial hydration therapy with dextrose 5% and 1/4 normal saline was followed within eight hours by transfusion with two units of packed red blood cells. Patency was restored to the occluded arterioles with return of normal acuity in LE, though the vision remains at hand motions in the RE. Sudden loss of central acuity in sickle hemoglobinopathies may result from vaso-occlusion in terminal arterioles near the foveal avascular zone. Therefore a reduced number of permanently irreversibly sickled red blood cells may prevent these macular infarcts.

Anemia, Sickle Cell↗
PubMedDate not supplied

Coats' disease: a study of 62 histologically confirmed cases.

We studied 62 eyes submitted to the Armed Forces Institute of Pathology (AFIP) from 1958 through 1980 that satisfied our criteria for the histologic diagnosis of Coats' disease. Our histopathologic definition of Coats' disease was the presence of a primary vascular lesion consisting of retinal telangiectasia with leakage of plasma to form intraretinal and subretinal exudates. In the cases we reviewed, Coats' disease occurred more frequently in boys, it usually affected only one eye, and was generally detected in the first decade of life. In 52 cases (79%) the clinical manifestations, strabismus and leukokoria, were thought to be caused by retinoblastoma. Angle closure glaucoma was present in 36 cases (58%). In all but one of the cases studied, the lesion was located peripheral to the equator. We further identified diffuse involvement of capillaries in the peripheral retina using trypsin-digest preparations. Associated histologic findings included: rubeosis iridis, cataract, vitreous neovascularization, and nodules resulting from fibrous metaplasia of the retinal pigment epithelium. These fibrous nodules typically occurred in the macular area and occasionally contained calcium or bone.

Child↗
PubMedDate not supplied

Infantile esotropia: results in the neurologic impaired and "normal" child at NCMH (six years).

Charts of all infantile esotropes who received their primary surgical procedure at the North Carolina Memorial Hospital, between February 1978 and June 1984 were reviewed. Neurologic problems (general and ocular) were identified in 29 of the 47 patients (61.7%) followed a minimum three months (mean = 25.0 +/- 2.9 mos). Frequent general neurologic problems were prematurity, hydrocephalus, mental retardation, cerebral palsy, meningomyelocele, intraventricular hemorrhage, and seizures (neonatal and/or postnatal). Abducens nerve palsy was the most common ocular neurologic impairment. Neurologic impaired esotropes were older (mean = 31.9 +/- 3.8 mos) than the "normal" group (mean = 17.0 +/- 3.3 mos) at the time of surgery. Recession/resection procedures were performed on 13 (44.8%) of the neurologically impaired and nine (50.0%) of the normal esotropes. Bimedial recessions were employed on 12 (41.4%) of the patients with neurologic problems and seven (38.8%) of the normal esotropes. Unilateral medial recessions and/or inferior oblique recessions were performed on six patients. At last follow-up, orthophoria (+/- 10 delta) was present in 16 (55.2%) neurologically impaired patients and 15 (83.3%) normal esotropes (p less than 0.05 by the normal deviate (z) test). Seven (24.1%) neurologically impaired patients had residual esotropia, while consecutive exotropia was present in six (20.7%) patients. Among normal esotropes, residual esotropia was found in one patient and consecutive exotropia in two (11.1%) patients. DVD's occurred in nine patients while four subjects developed a postoperative accommodative component.

Accommodation, Ocular↗