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Biomedical subjects

J R Samples

Publications and source records attributed to J R Samples.

At least 73 records · Page 4Linked to original sources
PubMed1985

An ophthalmic beta antagonist with rapid systemic deactivation.

The intraocular pressure response to ACC-9447, a topical beta adrenergic antagonist, in six drug concentrations from 0.2% to 4.0%, was evaluated in 17 normal human subjects. ACC-9447 employs a new strategy for reducing systemic effects of ocular drugs by exploiting physiologic blood esterases to deactivate the drug rapidly after systemic absorbtion. Each patient received the test drug in one eye and placebo in the fellow eye. Intraocular pressure was measured nine times over the subsequent 24-hour period. The tests were repeated for six increasing concentrations over six weekend days. Although the eyes receiving ACC-9447 exhibited a significant 24-hour reduction in pressure from baseline, the effect was not different in placebo-treated eyes. Further studies are planned in ocular hypertensive patients using matched patient rather than fellow eye controls.

Adrenergic beta-Antagonists↗
PubMed1984

Acanthamoeba keratitis possibly acquired from a hot tub.

An irritated left eye followed by a geographic epithelial corneal defect developed in a 42-year-old man. Disciform edema developed in the cornea, and the lesion progressed to a ring-shaped abscess. The lesion failed to respond to medical therapy. After two penetrating keratoplasties, histopathologic examination and electron microscopic studies established the diagnosis of Acanthamoeba keratitis. Subsequent cultures and immunofluorescent studies identified the organism as Acanthamoeba castellani. Following treatment with antibiotics and corneal cryotherapy, there has been no evidence of recurrence. Morphologically and immunologically identical amebae were also cultured from the patient's hot tub and surrounding garden.

Adult↗
PubMed1984

The value of the Terry keratometer in predicting postoperative astigmatism.

The Terry keratometer was used immediately before and immediately after cataract surgery. The results were compared with keratometry readings taken before surgery and readings taken on the morning of the first postoperative day. The mean preoperative cylinder in 27 eyes was 1/2 diopter less than that measured prior to the start of surgery. Preoperative readings and readings obtained prior to the start of surgery differed by more than 1 diopter in 37% of eyes. The keratometer readings obtained at the end of the surgery in 63 eyes were flatter than those obtained on the first postoperative day. Forty-four percent of the intraoperative cylinder readings differed from postoperative readings by more than 2 diopters. The factors which can produce errors with the use of this instrument include changes in intraocular pressure, the effect of the lid speculum, rectus suture tension, the alignment of the eye with respect to the keratometer , and user experience.

Aged↗
PubMed1984

Epithelial ingrowth on an intraocular lens.

Following 36 months of chronic uveitis and glaucoma, an epithelial membrane was documented over the retrocorneal surface, the iris, chamber intraocular lens, and surface of the intraocular lens. In spite of an inhospitable surface for cell growth, an intraocular lens can support the proliferation of epithelium.

Aged↗
PubMed1984

Morphology of hydrogel implants used for refractive keratoplasty.

The pathology of 14 keratophakia procedures in nine nonhuman primates using various hydrogel lenses as donor lenticles is presented. The lenses were treated as if they were human donor corneas using currently practiced keratophakia procedures. This included microkeratome resection of the recipient cornea, staining of the lenses before cryolathing and, in most instances, lathing according to a modified computer program after which the lenses were inserted into the previously dissected recipient lamellar bed. There was no histologic evidence of an inflammatory reaction to the hydrogels. The major pathologic feature was the presence of activated keratocytes lining the dissected intrastromal pockets.

Animals↗
PubMed1984

Epikeratophakia: clinical evaluation and histopathology of a non-human primate model.

We performed four aphakic and two myopic epikeratophakia procedures in a non-human primate model using two fresh and three prefrozen corneas and one glycerin-preserved cornea. The experiments were terminated 4 to 5 months postoperatively, and the eyes examined with correlative microscopy. The glycerin-preserved cornea sloughed and was not available for analysis. All but one prefrozen specimen demonstrated donor keratocyte repopulation. Active keratocytes were noted lining the optical interface. Focal areas of missing Bowman's layer were present in three recipient corneas. Epithelial interface ingrowth occurred in two specimens. The recipient corneas were otherwise normal.

Animals↗
PubMed1984

Contamination of irrigating solution used for cataract surgery.

A cloudy, floating opacity was found in a bottle of irrigating solution during routine cataract surgery. This was subsequently identified as Penicillium, and the patient was successfully treated. Surgeons are urged to check the containers of solutions used for intraocular irrigation prior to beginning surgery.

Aged↗
PubMed1984

Suppurative interstitial ring keratitis due to streptococcus.

Three cases of interstitial ring abscess of the cornea caused by different strains of streptococcus are described. These infections occurred in three different clinical settings: after penetrating trauma at the limbus, after a cataract operation, and in conjunction with keratoconjunctivitis sicca. The acute appearance of a light, interstitial ring not extending to the limbus in the post-traumatized eye should alert the clinician to the possibility that a streptococcus may be responsible. The ring frequently progresses rapidly to a total ring abscess with intraocular extension. The outcome was poor in all three patients.

Aged↗
PubMed1983

Syringomesencephalia. Report of a case.

A woman had progressive neurologic deterioration attributed to multiple sclerosis. Ophthalmologic findings were consistent with a unilateral lesion of the medial longitudinal fasciculus. Autopsy disclosed a mesencephalic syrinx and cerebellar atrophy secondary to alcoholism. Syringomesencephalia is distinctly uncommon; this is the third known case to our knowledge.

Adult↗
PubMed1983

Optic nerve meningioma.

An obese white woman presented with a 10-month history of progressive loss of vision in the right eye associated with a moderate proptosis. Examination of the fundus revealed marked congestion of the retinal vasculature with dilation of both the arteries and the veins. Numerous blot hemorrhages were scattered throughout the retina. The retina was elevated and appeared to be displaced anteriorly by solid tissue, but B-scan ultrasonography demonstrated only a serous detachment of a thickened, markedly convoluted retina. A diagnosis of optic nerve meningioma was considered, but definitive treatment was deferred because of medical problems. One month later the patient returned with a blind, painful right eye associated with neovascular glaucoma. High resolution CT coronal sections of the orbit showed generalized thickening of the optic nerve. The blind eye was enucleated facilitating exposure of the optic nerve which was found to be diffusely thickened by meningioma. The orbital portion of the optic nerve was subsequently removed and meningioma was demonstrated along its entire length to the bony optic canal. A transfrontal craniotomy was later performed to rid the patient of residual tumor.

Adult↗
PubMed1983

Ocular involvement in disseminated intravascular coagulation (DIC).

A 27-year-old white woman with anorexia, abdominal pain, arthralgias, spiking fever, diarrhea, and bizarre neurologic symptoms developed yellowish-gray plaques surrounded by hemorrhage in the posterior choroid of both eyes. Progressive thrombocytopenia, hypofibrinoginemia, and accelerated fibrinolysis supported the diagnosis of disseminated intravascular coagulation (DIC). Death occurred from complications of DIC. Widespread thrombotic occlusion of small blood vessels was present in numerous organs, including the posterior choriocapillaris and larger choroidal vessels of both eyes. Other ocular vessels were normal.

Adult↗
PubMed1981

Tobacco-alcohol amblyopia.

A series of 52 patients with scotomas attributed to tobacco smoking, alcohol consumption, and nutritional deficits--alone and in combination--was reviewed. Whether use of tobacco alone can produce a scotoma has been a controversial point; our series suggests that it can. Central and cecocentral scotomas did occur in association with smoking alone; there seems to be an association between cecocentral scotoma and cigar smoking especially. Central scotomas were seen more often in patients who consumed alcohol. Recovery from either type of scotoma was observed in 3 months when a therapeutic program of abstinence and B vitamins was followed. Although the number of patients we see with these scotomas has decreased, clinicians are urged to be aware of this disorder.

Aged↗
PubMed1977

Platelet aggregate ratios--standardization of technique and test results in patients with myocardial ischemia and patients with cerebrovascular disease.

The technique for measuring platelet aggregate ratios described by Wu and Hoak (1974) was evaluated in normal subjects. The following had no influence upon the test result: age, sex, fasting versu the postprandial state, and the degree of stasis prior to drawing the sample. Variance within subjects was small compared to variance between subjects (0.009 versus 0.0053, p less than 0.01). Platelet aggregate ratios were then measured in 36 patients with coronary artery disease hospitalized with acute chest pain. Their mean platelet aggregate ratio of 0.86 was identical to the mean ratio for 47 normal subjects. Greater variability was found within patients (between samples) than within the normal subjects. This observation raises doubts about the significance of a single measurement of platelet aggregate ratio in such acutely ill patients. Mean platelet aggregate ratios measured daily did not differ over a 7-day period between 11 patients who developed a myocardial infarction and 10 patients who did not. A normal mean platelet ratio was also found on a single measurement from 30 patients with a history of completed stroke (0.87) and from 11 patients with a history of transient ischemic attacks (0.92).

Adult↗
PubMed1977

Lethal effects of physostigmine plus lithium in rats.

The interaction between the reversible cholinesterase inhibitor, physostigmine, and lithium chloride was studied in adult male rats. A combination of lithium plus physostigmine increased lethality more than that caused by either physostigmine or lithium alone. Scopolamine completely reversed this effect. These drug interactions may have clinical significance, since lithium plus cholinesterase inhibitors may be used together in the practice of medicine.

Animals↗