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Biomedical subjects

C Hanna

Publications and source records attributed to C Hanna.

At least 55 records · Page 3Linked to original sources
PubMed1977

An ultrastructure study of posterior polymorphous dystrophy of the cornea.

The cornea from an early developing and uncomplicated case of posterior polymorphous dystrophy in a 15-year-old boy shows a thin abnormal Descemet's membrane and reduced number of endothelial cells as the primary findings. Ultrastructurally, the membrane was composed of a very thin, three-dimensional lattice pattern layer covered by layers of fibrous material. This lattice pattern is normally formed between late fetal and early adolescent life. The 3 previously reported histologic cases of this entity were from cases with long-standing corneal opacities in the late third to fifth decade of life with additional corneal changes. However, in each case the lattice pattern layer of the membrane was abnormally thin. This report suggests that a progressive form of posterior polymorphous dystrophy of the cornea is due to cells forming abnormal Descemet's membrane beginning in late fetal life to soon after birth.

Adolescent↗
PubMed1977

Effects of dimethyl sulfoxide on ocular inflammation.

The anti-inflammatory properties of topical ocular dimethyl sulfoxide (DMSO) were investigated using a standard experimental model of an acute inflammatory ocular inflammation. Ninety percent and 100% DMSO aggravated the inflammatory response, 50% to 70% DMSO had similar responses as the control eye; however, 30% DMSO had definite anti-inflammatory properties. Dexamethasone 0.1% was superior to 30% DMSO as an anti-inflammatory agent. From this study it is evident that high concentrations of DMSO are irritating to the inflammatory ocular model used while lower concentrations have anti-inflammatory properties. The two side effects of skin irritation at the site of application and breath odor may be the subjective influence that leads certain patients to report a beneficial effect of DMSO treatment in ocular inflammation.

Acute Disease↗
PubMed1977

Use of drugs in ointment for routine mydriasis.

The mydriatic effect produced by ointment preparations of cyclopentolate 1%, tropicamide 1%, and phenylephrine hydrochloride 10% was compared to the mydriasis elicited by the aqueous solutions of the same concentrations of drugs in children and adults. There was no difference in the amount of mydriasis produced by one instillation of a very small volume of the drug in ointment in one eye when compared to multiple instillations of the aqueous solution of the same drug in the contralateral eye in 30 minutes. There were no complaints of ocular irritation when the ointment preparations were instilled into the eye; however, there were frequent complaints with the use of these drugs in aqueous solutions.

Adolescent↗
PubMed1977

Idiopathic chorioretinal effusion: An analysis of extracellular fluids.

A case of nonrhegmatogenous retinal detachment with choroidal detachment was seen 3 weeks after onset and was evaluated clinically with emphasis on the fluid contents from one eye. The right eye showed slight subretinal fluid and minimal RPE pigmentary mottling. The left eye was severely involved with a near flat anterior chamber, a 360 degrees peripheral serous retinal detachment with shifting fluid and 360 degrees choroidal separations. Fluorescein showed mottled retinal pigment epithelium changes in each eye. Cell free samples of the subretinal fluid were high in protein (16.5 gm/100 ml) with a near absence of the alpha-2 fraction. Epichoroidal fluid from the choroidal detachments exhibited a protein content and makeup similar to that of normal plasma. The concentration of protein in the cerebrospinal fluid was elevated (0.096 gm/100 ml) without evidence of inflammatory changes. Ultrastructural examinations of sclera revealed a normal structure. There was no indication of the cause of the elevated protein content of the subretinal and spinal fluids. Following subretinal and epichoroidal fluid evacuation, the patient was treated with systemic steroids. The retinal and choroidal separations subsided slowly over several months, leaving multiple retinal pigment epithelial pigmentary clumps with drusen-like centers. A more appropriate name for this entity is idiopathic chorioretinal effusion.

Blood Proteins↗
PubMed1976

Recurrent tapioca melanoma of the iris and ciliary body treated with the argon laser.

A 25-year-old white woman underwent iridocyclectomy for an iris tumor. Clinically, histologically, and ultrastructurally this tumor was the same as a recently reported tapioca melanoma of the iris. During the next four months, there were recurrent growths on the ciliary body that we treated with the argon laser through a three-mirror lens. No further recurrences of the tumor were noted three years later.

Adult↗
PubMed1976

Effect of drug vehicle on human ocular retention of topically applied tetracycline.

Tetracycline hydrochloride--as a 1% suspension in oil, 1 and 2% suspension in ointment, and 1 and 2% solution in water or balanced salt solution USP--was applied once to the conjunctival cul-de-sacs of volunteers and patients before cataract extraction. The tear film concentrations of drug were maintained above a bacteriostatic level in excess of six hours for 1 and 2% tetracycline in ointment, less than two hours for 1% tetracycline in oil, and less than 30 minutes for 1 and 2% tetracycline in water or balanced salt solution. The 2% tetracycline in ointment produced the highest tear film levels of drug. The 1% tetracycline in oil induced excessive lacrimation and much of the drug was washed from the conjunctival surface. The tear film levels of the drug were mirrored by the maintenance of bacteriostatic levels of tetracycline in the aqueous humor for 1 1/2 hours with 2% tetracycline in ointment. Whereas 1% tetracycline in ointment produced drug levels approaching bacteriostasis in the aqueous humor, 1% tetracycline in oil produced only trace levels of the drug within the anterior chamber. The ointment acted as a depot for the suspended drug and most of the drug in the absence of excessive tearing was lost from the conjunctiva via the lacrimal system.

Administration, Topical↗
PubMed1975

Effects of drug vehicles on ocular contact time.

Radioactive sodium pentechnetate Tc 99m was added to commonly used ophthalmic drug vehicles of saline, 1% methyicellulose, 1.4% polyvinyl alcohol, and a 6:4 mixture of white petrolatum-mineral oil ointment. These drug vehicles containing 99m Tc were placed on both rabbit and human eyes and the rate of disappearance of the radioactivity determined. The ocular retention of 99m Tc by the eye was much longer in the nonblinking eye regardless of the vehicle used. The rate of loss of 99m Tc from the eye was fastest with saline and slowest with the ointment, with methylcellulose and polyvinyl alcohol in between. The longest contact time of the drug vehicle with the eye is afforded by the use of the ointment vehicle and the covering of both eyes.

Absorption↗
PubMed1975

Pseudoentrapment of ointment in the cornea.

A previously unrecognized characteristic clinical entity, "pseudoentrapment of ointment in the cornea" may occur in corneal lesions that have (1) topical application of ointments to the corneal lesion, (2) application of a firm pressure dressing, and (3) stromal loss or distortion of its normal architecture that allows for ointment globules to lie below the corneal surface. The clinical picture is that of a cluster of large ointment globules lodged within the corneal defect. Experimental data suggest that the ointment globules are entrapped within the wound exudates and lodged below the plane of the corneal surface. No treatment is necessary since the globules are extruded within the next 24 to 48 hours even if the pressure dressing is continued. Pseudoentrapment of ointment inthe cornea is compared with and differentiated from corneal ointment entrapment and corneal spheroidal degeneration.

Adult↗
PubMed1975

Subconjunctival and episcleral lipid globules.

Asymptomatic peripheral subconjunctival and episcleral clear, round globules, 30 to 50 mu in diameter, were found in more than 50% of patients over 50 years of age. This entity occurred in two basic patterns, adjacent to deep conjunctival or episcleral blood vessels or less commonly in isolated patches. These globules increased linearly with age, were more common in women and blacks, with a peak incidence in blacks during the fourth, and in whites, the sixth decade. Histologically, the globules were connective tissue fat cells identical to those found in orbital fat. This entity is not related to obesity, but has a clear relationship to increasing age. The clinical importance of these cells is unknown.

Adolescent↗
PubMed1975

Effects of drug vehicles on ocular uptake of tetracycline.

Varying concentrations of tetracycline hydrochloride were topically applied to the rabbit eye in several ophthalmic vehicles. The antibiotic levels in the corneal epithelium, aqueous humor, and lens were markedly elevated by increasing the drug concentration and the drug contact time with the eye. The ocular levels of tetracycline were increased by the vehicle in this ascending order: isotonic saline, 1.4% polyvinyl alcohol, 1% alpha-methylcellulose, and a 6:4 mixture of white petrolatum-mineral oil ointment. Tetracycline hydrochloride as a 2.0% suspension in ointment produced anterior chamber and corneal concentrations for several hours in the range of bacteriostasis for many gram-negative bacteria that occasionally invade the eye.

Absorption↗