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Biomedical subjects

G L White

Publications and source records attributed to G L White.

At least 73 records · Page 4Linked to original sources
PubMed1988

Prevention of the rise in intraocular pressure following neodymium-YAG posterior capsulotomy using topical 1% apraclonidine.

We studied apraclonidine hydrochloride (aplonidine hydrochloride or ALO 2145), an alpha-agonist, for its effect on the intraocular pressure (IOP) rise following neodymium-YAG posterior capsulotomy (YPC). In a prospective multicentered double-masked study, 63 eyes were pretreated with one drop of either 1% apraclonidine hydrochloride or placebo one hour before performing YPC and again following the laser treatment. The greatest IOP rise in the placebo-treated eyes occurred in the third hour after YPC, when the mean (+/- SD) IOP rose from a baseline pressure of 16.4 +/- 3.7 to 20.8 +/- 6.8 mm Hg. In apraclonidine-treated eyes, the IOP fell from a mean of 15.6 +/- 3.8 to 12.8 +/- 6.0 mm Hg three hours postoperatively. There were five times as many eyes that had an IOP rise greater than 10 mm Hg in the placebo-treated group compared with those treated with apraclonidine. Apraclonidine proved to be highly effective in preventing the rise in IOP following YPC.

Administration, Topical↗
PubMed1988

Orbital emphysema: a potentially blinding complication following orbital fractures.

A case of visual loss due to orbital emphysema secondary to a blow-out fracture of the orbit is presented. Because vision returned to 20/20 following an optic nerve decompression procedure, we hypothesize that our patient developed a compressive optic neuropathy with ischemia due to the emphysema. Essential instructions concerning the injury that the emergency physician should give the patient suffering an orbital blow-out are also presented.

Adolescent↗
PubMed1988

Effectiveness of apraclonidine in preventing the rise in intraocular pressure after neodymium:YAG posterior capsulotomy.

Apraclonidine (para-aminoclonidine) is an alpha agonist that was studied for its effect on the IOP rise following YPC. In a prospective multicentered double-masked study 63 eyes were pretreated with one drop of either 1% apraclonidine or placebo 1 hour prior to performing YAG and again after the laser treatment. The greatest IOP rise in the placebo-treated eyes occurred in the third hour after YPC when the mean IOP rose from a baseline pressure of 16.4 +/- 3.7 mm Hg to 20.8 +/- 6.8 mm Hg (P less than .01). In apraclonidine-treated eyes the IOP fell from a mean of 15.6 +/- 3.8 mm Hg to 12.8 +/- 6.0 mm Hg 3 hours postoperatively (P less than .001). There were five times as many eyes that had a pressure rise greater than 10 mm Hg in the placebo-treated group compared to those treated with apraclonidine. Apraclonidine proved to be highly effective in preventing the rise in IOP following YPC.

Administration, Topical↗
PubMed1988

Corneal transplantation.

Corneal transplantation has become increasingly successful as a result of improved methods of tissue procurement and preservation, refined surgical techniques, better medical care, heightened public awareness and an expanded network of eye banks. Vision improves within a day of surgery and continues to improve for six months to one year. Careful screening of donors and donor corneal tissue is essential. Causes of transplantation failure include rejection, glaucoma and recurrent infections.

Corneal Transplantation↗
PubMed1988

Contact lens care and complications.

In the past 20 years, great strides have been made in contact lens technology, but this progress has been accompanied by a multitude of lens-related problems. Bacterial keratitis may be the most significant problem, but reports of Acanthamoeba keratitis, a parasitic corneal infection, are increasing. Infectious complications may be lessened by proper lens care. Thermal disinfection is recommended for soft lenses with a low water content; chemical decontamination is preferred for soft contact lenses with a high water content.

Amebiasis↗
PubMed1986

Humanitarian responsibilities and corporate medicine.

The practitioner's moral mandate to administer to those in need is seriously compromised by recent changes in the medical marketplace. A clinician and an administrator encourage emerging medical corporations voluntarily to assume more responsibility for the poor and indigent. They also challenge PAs to champion the cause of those who cannot afford proper medical attention.

Economics, Hospital↗
PubMed1986

What patients should know about radial keratotomy.

Radial keratotomy is a relatively new, widely advertised procedure that promises patients with myopia 20/20 vision without corrective lenses. However, radial keratotomy sometimes does not fulfill this promise. New studies have reported numerous cases in which patients were not helped or were actually harmed by radial keratotomy. Also, its long-term effects are unknown. Family physicians should advise patients to approach the procedure with caution.

Cornea↗
PubMed1986

Longitudinal evaluation of pulmonary function in copper smelter workers exposed to sulfur dioxide.

From 1973 to 1974, a longitudinal study of pulmonary function in 113 Utah copper smelter workers reported significant declines in FVC and FEV1 related to sulfur dioxide exposure. In 1980, we performed a 7-yr follow-up study, finding significant increases in FVC and FEV1. The 66 follow-up participants were similar to those 47 lost to follow-up with regard to age and initial pulmonary function. Subgroups of smelter workers with initial higher exposures to sulfur dioxide and FEV1 less than 90% predicted did not show an accelerated rate of decline. To reconcile these differences between the 2 studies, we reevaluated the spirometry curves from 1973 and 1974. All had short expiratory times, with none 6 s or longer, whereas all of the curves from the spirograms obtained in 1980 exceeded 6 s. In addition, from 1980 to 1983, we performed a longitudinal study of 48 of the original workers, finding small annual mean declines for FVC of 6 ml and FEV1 of 5 ml. Personal exposures to sulfur dioxide were not significantly different in 1982 than in 1976; thus, we were unable to corroborate the findings of the initial longitudinal study.

Copper↗
PubMed1985

Mutagenic activation of 2-aminofluorene by fluorescent light.

To determine the effect of artificially produced light on the direct mutagenicity of 2-aminofluorene, that arylamine was irradiated with either sun, cool-white, black, blue, or yellow fluorescent light or held in the dark prior to assaying for mutagenicity using Salmonella typhimurium strain TA98. The effectiveness of these exposures in potentiating the mutagenicity of 2-aminofluorene was sun greater than black greater than cool-white greater than blue greater than yellow approximately equal to dark. By varying the radiant flux densities produced by the lamps and using optical filters, wavelengths of light up to approximately 450 nm were found to be effective in the mutagenic potentiation. Studies using radical scavengers and oxygen modifiers indicated that the light-induced mutagenicity was dependent on oxygen and that singlet oxygen may be an effective activator of 2-aminofluorene. The mutagenicity of fluorene was not increased by exposure to light, while only sunlight potentiated the mutagenicity of 2-acetylaminofluorene. This result suggested the importance of the primary amine in the mutagenic activation of 2-aminofluorene by light. Light-activated 2-aminofluorene was less mutagenic in strains TA98NR and TA98/1,8-DNP6 than in TA98. This observation, combined with the dependence of the photoactivation on oxygen and amino-substitution, indicated that the light-enhanced mutagenicity was at least partially due to N-oxidized photoproducts. These studies indicate that the effect of light on environmental contaminants must be considered in assessing their genotoxic potential.

Animals↗
PubMed1985

Fungal metabolism and detoxification of polycyclic aromatic hydrocarbons.

The mutagenic activity of ethyl acetate extracts of culture medium from Cunninghamella elegans incubated 72 h with various polycyclic aromatic hydrocarbons (PAHs) was evaluated in the Salmonella typhimurium reversion assay. All of the PAH extracts were assayed in tester strains TA98 and TA100 both with and without metabolic activation using a liver fraction from Aroclor 1254-treated rats. None of the extracts from fungal incubations with the mutagenic PAHs, benzo[a]pyrene, 7,12-dimethylbenz[a]anthracene, 3-methylcholanthrene and benz[a]anthracene, as well as the non-mutagenic PAHs, naphthalene, phenanthrene and anthracene, displayed any appreciable mutagenic activity. In addition, time course experiments indicated that the rate of decrease in mutagenic activity in the extracts from cultures incubated with benzo[a]pyrene or 7,12-dimethylbenz[a]anthracene was coincident with the rate of increase in total metabolism. The results demonstrated the ability of the fungus C. elegans to detoxify known carcinogens and mutagens and suggests that this organism may play an important role in the metabolism and inactivation of PAHs in the environment.

Animals↗