William Jefferson Darby, Jr., M.D., Ph.D.--nutritionist.
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Arkansas↗
Biomedical subjects
C Hanna
Publications and source records attributed to C Hanna.
Influence of drug vehicle on ocular contact time of sulfacetamide sodium.
Sulfacetamide sodium drops and ointments were applied to the conjunctiva of patients and volunteers. Tear samples were taken and analyzed for sulfacetamide sodium content. The minimal inhibitory concentrations of the drug in para-aminobenzoic acid-free media were determined to be between 20 and 50 micrograms/mL against Escherichia coli and Staphylococcus aureus, and the effective concentrations of the sulfa were taken as 50 micrograms/mL. The concentration of sulfacetamide sodium in tears fell to the 50 micrograms/mL level in 30 minutes, two hours, and five and a half hours after the single application of 10 microL of 15% and 30% drops and 25 microL of all three ointments, respectively. The ocular contact time of the sulfa was increased by increasing the concentration of drug. The makeup of the three ointments differed greatly, yet the ocular contact time was similar.
Escherichia coli↗
Adverse effects of iron supplementation: a comparative trial of a wax-matrix iron preparation and conventional ferrous sulfate tablets.
The acceptability of supplemental iron delivered from a wax-matrix tablet of ferrous sulfate was compared with that of a conventional ferrous sulfate tablet in a single-blind, parallel-group study. Both tablets were formulated to deliver 50 mg of elemental iron. The incidence of adverse effects was found to be significantly greater among 272 subjects taking the conventional tablets than among 271 subjects taking the wax-matrix preparation. Eighty-one percent of the subjects taking the wax-matrix preparation experienced no severe or moderate side effects as compared with only 50% of those taking the conventional tablets.
Adolescent↗
Treatment of glaucoma using minidrops of clonidine.
A single regular (70 microL) or mini (15 microL) eyedrop of 0% (placebo), 0.25%, and 0.50% strengths of clonidine hydrochloride was administered to 16 patients with open-angle glaucoma in a double-masked crossover study. Both the regular drops and minidrops of 0.25% and 0.50% concentrations of the drug substantially lowered the intraocular pressure over a five-hour period as compared with the placebo. Only the regular drops of 0.50% clonidine substantially lowered the systemic BP. These results indicate the value of using a smaller volume of clonidine drop as an ocular hypotensive agent to avoid systemic effects.
Adult↗
Ocular penetration of amikacin following intramuscular injection.
Amikacin sulfate was given intramuscularly (IM) (7.5 mg/kg) to study its ocular penetration in man. Seventy-three patients with cataracts received a single dose and 35 received two doses given 5 1/2 to 12 hours apart. After a single dose the aqueous humor levels of the antibiotic between two and ten hours ranged from 0.15 to 3.10 mg/L (average and median, 1.0 mg/L). Two doses given 5 1/2 to eight hours apart produced an average level of 3.5 mg/L (range, 0.91 to 8.31 mg/L). When the second dose was given nine to 12 hours after the first, the aqueous humor levels were similar to those found for a single dose. Aqueous humor concentrations of 1.0 mg/L of amikacin would be expected to be bactericidal for most gram-negative bacterial pathogens, whereas levels of 3.5 mg/L would inhibit most strains of Staphylococcus aureus and many strains of Pseudomonas aeruginosa.
Adult↗
Allergic dermatoconjunctivitis caused by phenylephrine.
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Conjunctivitis↗
Evaluation of superoxide dismutase (orgotein) in medical treatment of canine cataract.
Orgotein (Palosein) is a veterinary product with marked superoxide dismutase activity that has been used intracamerally to treat senile cataracts in the dog. Fourteen old dogs with bilateral senile cataracts were injected twice in one eye with orgotein and twice in the other eye with isotonic saline under masked conditions. Observations were made over an average of a 12-week period. No clearing of lenses could be detected and there was no observed subjective improvement in the dogs' visual behavior.
Animals↗
Cataracts associated with allopurinol therapy.
The National Registry of Drug-Induced Ocular Side Effects has accumulated 30 cases of suspected allopurinol-induced lens changes. The cataracts associated with this antihyperuricemic agent are initially anterior and posterior lens capsule changes with anterior subcapsular vacuoles. With time, wedge-shaped anterior and posterior cortical haze occurs, along with dense posterior subcapsular cataracts. Histologic studies of these cataracts showed no unique or identifying features. These cases do not prove a cause-and-effect relationship, but raise the suspicion that allopurinol may be cataractogenic in some patients. Additional case reports and lens material should be sent to the National Registry of Drug-Induced Ocular Side Effects, Oregon Health Sciences University, 3181 S.W. Sam Jackson Park Rd., Portland, OR 97201.
Adult↗
Mydriasis from topically administered phenylephrine HCl powder.
Microgram amounts of finely powdered phenylephrine HCl were administered to the conjunctiva of volunteers. A dose-response curve for white subjects showed a threshold mydriasis of less than 5 micrograms and a clinically useful mydriasis was obtained with one application of 50 micrograms. The time-response curve for the one time use of 50 micrograms of the powder was equivalent to giving three applications of 10% phenylephrine HCl drops. Twenty-five micrograms of pilocarpine HCl powder produced marked miosis. We investigated methods to deliver nonirritating microgram amounts of powdered phenylephrine HCl, pilocarpine HCl, and fluorescein.
Adult↗
Nurse training and staffing in the neonatal intensive care unit.
Most nurses are unfamiliar with the highly sophisticated level of technology that must be utilized in the delivery of care in an NICU. This article has presented the measures that are utilized at one medical center to provide the nursing staff for its NICU. The presentation focused on the organization, selection, and development of a nursing staff that is capable of delivering a sophisticated level of care to sick neonates. However, it should be emphasized that it is essential to be alert to changes in patient therapies and related technology that may well alter the practice of neonatal intensive care nursing.
Decision Making↗
Evaluation of drugs in ointment for mydriasis and cycloplegia.
Ointment preparations of cyclopentolate hydrochloride and tropicamide were compared with aqueous drops of these medications for the production of mydriasis and/or cycloplegia in clinic patients. Mydriasis and/or cycloplegia could be accomplished by the single application of a minute volume (around 0.005 ml) of ointment containing these drugs. With the use of ointment preparation, ocular irritation was minimal, and there was no interference with subsequent ocular examination. A delivery system was devised with a piece of silicone-rubber tubing that was filled with an ointment preparation. By squeezing the tubing, a minute volume (about 0.005 ml) of ointment preparation was expressed.
Accommodation, Ocular↗
Ocular penetration of topical chloramphenicol in humans.
Commercial ophthalmic chloramphenicol solutions and ointments were applied to human eyes, and the concentrations of chloramphenicol in aqueous humor and tear samples were analyzed using gas-liquid chromatography. Within several minutes after a single application of 0.5% chloramphenicol solution, the tear concentrations of the drug had fallen below 1 mg/liter, the minimal bacteriostatic concentration for many ocular pathogens. Repeated drops of 0.5% chloramphenicol solutions during several hours were required to produce an aqueous humor concentration of 1 mg/liter. A single application of 1% chloramphenicol ointment gave prolonged drug concentrations in the tears and aqueous humor, falling to 1 mg/liter in two to four hours. The repeated use of chloramphenicol solution or ointment was well tolerated by the patients. We conclude that the penetration of chloramphenicol in the anterior segment of the eye is best carried out by the repeated application of chloramphenicol ointment.
Administration, Topical↗
Endothelial cell population changes of human cornea during life.
A photo slit lamp was used to obtain color, specular reflex, high magnification photographs of the corneal endothelium of subjects ranging in age from 3 to 88 years. Multiple areas of the cornea were examined to determine the endothelial cell population. No appreciable difference in cell density was found between the right and left eyes of the subjects nor between male and female subjects of similar age. Apparent defects in the endothelial cell coverage of Descemets membrane were found in subjects as young as 20 years of age and with increased frequency in older age groups. These defects were at times associated with variations in endothelial cell populations between the central and peripheral cornea. The average corneal cell population fell from nearly 1 million cells in the first years of life to about one third that number by the eight decade of life.
Adolescent↗
Use of dilute drug solutions for routine cycloplegia and mydriasis.
Clinic patients and students were given several regular drops of commercial 10% phenylephrine HCl, and 1.0% cyclopentolate HCl or 1.0% tropicamide HCl. The drops were given three times at five-minute intervals. Mydriasis and cycloplegia were determined and compared with the results obtained by using one of the following: microdrops (0.005 or 0.01 ml) of a mixture of 5% phenylephrine HCl and 0.5% tropicamide HCl, or regular drops of mixtures of 1% phenylephrine HCl, or 0.4% hydroxyamphetamine hydrobromide with 0.1% cyclopentolate HCl, or 0.1% tropicamide in a vehicle of 1.6% or 1.0% methylcellulose 400, or artificial tears or lubricants (Absorbobase, Contique, Isopto Tears, Liquifilm, Lyteers, Ultra Tears). Except for an initial lag in the production of mydriasis with the diluted mixtures, the results were similar for all preparations. The diluted solutions produced little ocular irritation or tearing.
Adolescent↗
Route of absorption of drug and ointment after application to the eye.
Chloramphenicol, tetracycline hydrochloride, sodium sulfacetamide, and fluorescein sodium prepared in both aqueous solutions and ointments were placed in the conjunctival sac of humans. Each drug soon was tasted in the back of the mouth with no difference being noticed with the use of aqueous solution or ointment. Tetracycline and fluorescein studies showed that systemic absorption were similar regardless of whether solution or ointment were used. Furthermore, it was found that the ointment passed through the lacrimal drainage system and into the nose and throat. The ocular contact time of ointment with the eye is greater than that of water, and ointment is much more slowly absorbed via the lacrimal drainage system. Both the drugs and the ointment base applied topically to the eye travel through the nasolacrimal system as the way of elimination when given in the small volumes that are held by the conjunctival sac.
Absorption↗
Foreign body granuloma of the conjunctiva.
Foreign body granulomas of the conjunctiva of children and deer were studied. The granulomas can develop rapidly and may not be readily diagnosed.
Animals↗
Ocular penetration of chloramphenicol. Effects of route of administration.
Chloramphenicol was applied topically to the eye in ointment, as a powder, or injected subconjunctivally and intravenously in rabbits. Aqueous humor samples were taken at varying time intervals up to six hours and analyzed for chloramphenicol using gas-liquid chromatography. The topical route using ointment and the subconjunctival injection route produced bacteriostatic concentrations of chloramphenicol in the aqueous humor lasting for several hours, while the topical powder and intravenous routes yielded relatively low concentrations. As compared with the other means of drug delivery, ointment was the most efficient in that it provided the highest aqueous concentration per total amount of drug administered.
Animals↗
Use of a spray to deliver drugs to the eye.
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Administration, Topical↗