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J R Samples

Publications and source records attributed to J R Samples.

At least 55 records · Page 3Linked to original sources
PubMed1987

The corneal endothelium after laser therapy for glaucoma.

Using computer assisted morphologic analysis of central corneal endothelial specular micrographs, we prospectively examined the effects of glaucoma laser procedures on the corneal endothelium. Argon laser trabeculoplasty was performed in 22 eyes of 17 patients. Argon laser iridotomy was performed in 14 eyes of seven patients. Untreated fellow eyes in ten patients undergoing laser trabeculoplasty were used as controls. After one year, no statistically significant difference in cell area, percent hexagonal cells, or shape factor was observed. Our results suggest that argon laser procedures do not pose any long-term hazard to the corneal endothelium.

Cornea↗
PubMed1987

Pupillary block with posterior chamber intraocular lenses.

We present 12 cases of pupillary block associated with extracapsular cataract extraction and posterior chamber intraocular lenses. In one case, pupillary block occurred despite the presence of a surgical iridectomy. The other 11 patients did not have a surgical iridectomy performed. We recommend that a surgical iridectomy or laser iridotomy be performed in all patients who undergo extracapsular cataract extraction with the implantation of posterior chamber intraocular lenses. Ophthalmologists need to be vigilant in watching for the development of pupillary block in these patients, since pupillary block is not a benign event and serious visual loss or disability may occur.

Aged↗
PubMed1987

Ocular inflammatory effects of intravitreal interleukin 1.

Locally injected endotoxin induces potent inflammatory changes in the rabbit eye. To clarify the possible role of interleukin 1 (Il-1), an endotoxin-induced monokine, in rabbit eye inflammation, we injected rabbits with recombinant Il-1 (rIl-1). Twelve and a half to 200 U of intravitreally injected rIl-1 consistently induced inflammation, which was documented using slit-lamp biomicroscopy, histologic methods, or direct quantitation of protein in the aqueous humor. Responses including a cellular infiltrate in the anterior chamber, protein extravasation, and iris vessel dilatation became evident within six hours, peaked at 24 hours, and began to recede by 48 to 72 hours after the injection. Pathologic changes primarily occurred in the anterior chamber and included edema, hemorrhage, and cellular infiltration. Locally injected corticosteroid reduced but did not prevent rIl-1-induced changes in vascular permeability. Heat-inactivated rIl-1 induced minimal changes, as determined by histologic methods, slit-lamp examination, or direct protein measurement. These data support the conclusion that Il-1 should be considered as a potential mediator of ocular inflammation.

Animals↗
PubMed1987

Chemotactic activity of lens proteins and the pathogenesis of phacolytic glaucoma.

Leakage of lens proteins from a hypermature cataract can result in a characteristic glaucoma that is associated with the invasion of the anterior chamber by monocytes. We hypothesized that the lens proteins themselves might account for the monocyte response. A sonicated lens induced concentration-dependent migration of monocytes in a Boyden chamber assay system. Checkerboard analysis indicated that the movement was directed rather than merely random. Relative to a control chemoattractant, N-formyl-methionyl-leucyl-phenylalanine, the lens induced monocyte migration more potently than neutrophil migration. The ability to induce migration was markedly reduced by incubating the lens with either trypsin or papain. Chemotactic activity was readily demonstrable in lenses from young donors without cataracts. Separation of lens proteins by gel filtration with high-performance liquid chromatography indicated that the chemotactic activity was most consistently associated with the gamma crystallin fraction. The chemotactic activity of lens proteins may contribute to the pathogenesis of phacolytic glaucoma or the uveitis resulting from retained cortical material after cataract extraction.

Aging↗
PubMed1987

Chemotactic activity in aqueous humor from patients with anterior uveitis.

Anterior uveitis, inflammation of the iris or ciliary body of the eye, may be associated with a variety of systemic diseases. Although a leukocytic infiltrate is characteristic of anterior uveitis, few studies have sought to detect factors in aqueous humor that could attract neutrophils or monocytes into the anterior chamber. Using modified Boyden chambers, we found that a 5% concentration of aqueous humor from patients with anterior uveal inflammation induced monocyte movement comparable to optimal or near-optimal concentrations of C (complement)5a or platelet-derived growth factor. Aqueous humor from patients with anterior uveitis induced significantly more monocyte migration than did aqueous humor from two sets of controls (either patients undergoing cataract extraction or patients with posterior uveitis). "Checkerboard" or gradient analysis indicated that a majority of inflammatory disease samples induced monocyte chemotaxis (directed migration) while the control aqueous humor consistently induced chemokinesis (stimulated random migration) (P less than 0.02). Despite their ability to induce monocyte migration, samples tended to induce minimal neutrophil migration with the exception of aqueous humor that was obtained from one patient with acute anterior disease. This sample induced marked chemokinesis. Identification of chemotactic activity may clarify the pathogenesis of uveitis and the characterization of leukocyte migration factors in aqueous humor may help define subsets of anterior uveal inflammation.

Aqueous Humor↗
PubMed1987

Three-year efficacy of argon laser trabeculoplasty.

The authors report on the effect of argon laser trabeculoplasty on intraocular pressure (IOP) over a 3-year period with a mean follow-up period of 1.8 years in patients with uncontrolled primary open-angle glaucoma who had not undergone prior surgery. An analysis of the effect of laser trabeculoplasty using the criteria for success of an IOP of 22 mmHg or less with no further laser trabeculoplasty or glaucoma surgery, showed a cumulative success of 79% (112 eyes) at 1 year, 69% (85 eyes) at 2 years, and 59% (58 eyes) at 3 years. Similar results are presented for 22 eyes from patients with pseudoexfoliation glaucoma. The authors conclude that although the initial success rate of laser trabeculoplasty is high, it diminishes progressively over time.

Actuarial Analysis↗
PubMed1986

Open-angle glaucoma associated with vitreous humor filling the anterior chamber.

We studied the diagnostic features of vitreous humor filling the anterior chamber in open-angle glaucoma in one patient who developed this phenomenon several years after an intracapsular cataract extraction. In two other patients, vitreous filled the anterior chamber after ocular trauma. These patients had markedly increased intraocular pressures that responded poorly to medical therapy. Follow-up of at least one year with each of our patients suggests that with vitrectomy they have done well.

Aged↗
PubMed1986

Reopening filtration fistulas with the neodymium-YAG laser.

We used the mode-locked neodymium-YAG laser to reopen filtration fistulas in nine eyes in which the fistula had become occluded internally by a variably pigmented membrane, vitreous, or, in one case, capsular lens material. In five eyes filtration was successfully reestablished, reducing the intraocular pressure to less than 21 mm Hg (range, 10 to 20 mm Hg). The remaining four eyes had fistulas thought to be open internally after laser treatment; however, filtration was not established because of external subconjunctival scarring of the bleb. As with needling or argon laser fistular reopening, successful filtration followed Nd-YAG laser fistular surgery only when the fistula was occluded by an identifiable membrane and when the eye already had had a well-established bleb.

Cicatrix↗
PubMed1986

The use of plasma melatonin levels and light in the assessment and treatment of chronobiologic sleep and mood disorders.

Using the highly accurate and sensitive gas chromatographic-negative chemical ionization mass spectrometric assay for plasma melatonin we have measured plasma melatonin in humans as a biological marker for 24-hour (circadian) and seasonal rhythms and the effects of light on these rhythms. We propose that there are at least three critical parameters for light to be chronobiologically active in humans: intensity, wavelength and timing. With regard to timing, we have found that bright light exposure in the morning advances circadian rhythms (shifts them to an earlier time) and bright light in the evening delays them (shifts them to a later time). We have suggested that chronobiologic sleep and mood disorders be "phase typed" into either the phase advance subtype or the phase delayed subtype and that these disorders can then be treated with either evening light (for phase advanced disorders) or morning light (for phase delayed disorders). Regarding the function of melatonin in humans, we have preliminary evidence that it may participate in the regulation of the circadian rhythm of intraocular pressure.

Biological Clocks↗
PubMed1986

Growth characteristics of primate (baboon) corneal endothelium in vitro.

Primate (baboon) corneal endothelial cells have been grown continuously in vitro for over 40 passages. Endothelial cells migrated from the explants within three to five days. Growth became confluent by 14 to 21 days; the cells in culture were polygonal in shape and formed a compact monolayer. In passages one to four, cells divided with a doubling time of 72 hours; this increased to 96 hours after the 16th passage. Even though the general morphological appearance was unchanged in passages greater than 10, the cells became irregular, exhibiting an enlarged and elongated profile. The addition of epidermal growth factor to the medium resulted in increased cell growth. Cultured cells were successfully transplanted onto Descemet's membrane of de-endothelialized baboon corneas. This study demonstrates that primate corneal endothelial cells can be grown continuously in tissue culture and subsequently transplanted in vitro.

Animals↗
PubMed1985

Pigmentary glaucoma associated with posterior chamber intraocular lenses.

Six cases of glaucoma associated with pigment dispersion syndrome occurred after the implantation of posterior chamber intraocular lenses. All six patients had iris transillumination defects associated with the intraocular lens haptics, increased intraocular pressure, and pigment deposition in the trabecular meshwork and the anterior chamber. Medication controlled the glaucoma and none of the patients required further surgery.

Aged↗
PubMed1985

Optic nerve head drusen and glaucoma.

The simultaneous occurrence of both optic nerve head drusen and glaucoma may make it difficult to evaluate visual field defects and the appearance of the optic nerve head. We saw five patients with both conditions, of whom four had pigmentary glaucoma or pigmentary dispersion syndrome. Drusen do not preclude the development of cupping, and they make it difficult to interpret its significance. Management of these patients requires serial visual field testing, serial disc photographs, and treatment aimed at keeping the intraocular pressures as low as possible.

Adult↗
PubMed1985

Effect of hydrocortisone on corneal endothelial cells in vitro.

The effect of hydrocortisone on the growth potential of human and baboon corneal endothelial cells in tissue culture was evaluated. Hydrocortisone-21-sodium succinate was incorporated into growth medium at 10(-3) to 10(-7) M concentrations in a standard tissue culture medium. Inclusion of hydrocortisone into growth medium at higher concentrations (e.g. 10(-4) and 10(-3) M) resulted in a significantly reduced cell growth and a decreased level of DNA synthesis. Higher concentrations of hydrocortisone induced morphological alterations in the corneal endothelial cells in vitro. The incorporation of 5% dextran into the growth medium failed to alter the negative hydrocortisone effects. These experiments suggest the potential adverse effects of hydrocortisone for the corneal endothelium in vitro when used at higher concentrations.

Adolescent↗
PubMed1985

Myectomy for essential blepharospasm.

Essential blepharospasm is a progressive, bilateral, involuntary facial spasm. In this study, we conducted a prospective analysis of myectomy for the treatment of this condition in 21 patients. The procedure consisted of extirpation of the muscles that close the eyelids (protractors), which include the pretarsal, preseptal, and orbital components of the orbicularis oculi, as well as the procerus and corrugator supercilii muscles of the brow. In addition, the muscles that open the eyelids (retractors) were strengthened (by resection of the frontalis muscle and repair of disinsertion of the levator aponeuroses). The most common symptoms that necessitated myectomy were difficulty with driving (20 patients), watching television (17 patients), reading (15 patients), and eating (5 patients). Overall, the 21 patients had a 70% mean decrease in symptoms postoperatively. Five patients required an additional operation for management of residual blepharospasm.

Aged↗
PubMed1985

Visual acuity, refractive error, and astigmatism following corneal transplantation for pseudophakic bullous keratopathy.

Seventy-six corneal transplants performed by one surgeon for pseudophakic bullous keratopathy (PBK) were studied. The mean follow-up was 23 months (range 2-76). Of 41 eyes with lenses left in situ, the mean acuity was 20/45; 60.9% of the eyes saw 20/40 or better. In contrast, the mean acuity for 18 eyes with lens removal and 17 eyes with intraocular lens exchange was 20/52 and 20/62, respectively; 42.8% saw 20/40 or better. Eighty-three percent of all grafts remained clear. Vitreous loss, glaucoma, and cystoid macular edema were more common with eyes with lens removals and exchanges. The type of lens present at transplant for PBK did not affect visual outcome. Although the results were not statistically significant, this study suggests that lenses left in situ are associated with a better visual prognosis, and that there is no difference in the clinical results between aphakic and pseudophakic bullous keratopathy.

Aged↗