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Biomedical subjects

C A Paterson

Publications and source records attributed to C A Paterson.

At least 127 records · Page 7Linked to original sources
PubMed1976

Ascorbic acid prevents corneal ulceration and perforation following experimental alkali burns.

Depressed aqueous humor glucose and ascorbic acid levels returned to control values within 14 days following a 20 sec, 6 mm. diameter, 1N sodium hydroxide burn of the rabbit cornea. These corneas did not ulcerate or perforate. After a 20 sec., 12 mm. diameter, 1N sodium hydroxide burn, aqueous humor glucose levels returned to normal values, but ascorbic acid levels remained significantly depressed for up to 30 days. These corneas became markedly ulcerated in about 60 per cent of animals and frequently perforated. Following 12 mm. alkali burns, rabbits treated daily with 1.5 Gm. of subcutaneous ascorbic acid rarely developed corneal ulcerations and the corneas did not perforate. It is suggested that exogenous maintenance of adequate aqueous humor levels of ascorbic acid overcomes the relatively scorbutic state of the anterior segment induced by a 12 mm. alkali burn, thereby impairing the development of corneal ulceration and perforation. Elevated aqueous humor levels of ascorbic acid had no influence on corneal epithelial cell migration patterns following alkali burns.

Alkalies↗
PubMed1975

An electrogenic component of the potential difference in the rabbit lens.

The normal resting potential of the rabbit lens, -70mV, is altered to -59mV by ouabain concentrations up to 5-1- minus 6M, and to -52mV at 4 degrees C. Ouabain acts only at the anterior lens surface. The temperature effect id completely reversible. The Hodgkin-Katz-Goldman equation can be used with the measured lens potentials and Na+ and K+ levels in the lens and bathing medium to obtain alpha, the ration of the membrane permeabilities to Na+ and K+. The alpha-values obtained were 0.052 at 4 degrees C and 0.053 in 5-10 minus 6M ouabain. These data suggest that the change in potential due to cold and ouabain is caused by an inhibition of an electrogenic Na+ ump in the anterior lens epithelium.

Animals↗
PubMed1975

Aqueous humor pH changes after experimental alkali burns.

Following application of 2N sodium hydroxide, or 8.1N ammonium hydroxide to rabbit cornea, the aqueous humor pH reached a maximum of 10.2, 11.9, and 12 within six minutes following 20-, 50-, and 100-mu1 sodium hydroxide burns, respectively; after two hours the pH had fallen to 8.5, 10, and 10.5. The maximum rise following application of 100-mu1 of ammonium hydroxide was 10.8, declining to about 9 at two hours. The fall in pH following a 100-mu1 sodium hydroxide burn was not greatly influence by external lavage. However, the pH was significantly lowered (12 to 10) by paracentesis alone and further reduced by immediate or delayed intracameral administration of phosphate buffer. On the basis of these results moderately severe and severe alkali burns of the eye should be treated by paracentesis and if possible with anterior chamber reformation with a sterile solution.

Alkalies↗
PubMed1975

Prostaglandin-like activity in the aqueous humor following alkali burns.

Following application of 20 mul of 2 N sodium hydroxide to the rabbit cornea, the prostaglandin-like activity in the aqueous humor increased from undetectable levels to around 30 ng, per milliliter, a level which was sustained for up to 24 hours. This increase correlated with the previously reported sustained elevation of intraocular pressure following a 20 mul alkali burn. Pretreatment with aspirin or indomethacin virtually abolished the increase in intraocular pressure and elevation of prostaglandin-like activity in the aqueous humor following a 20 mul burn. Marked ocular hypotension following 50 mul and 100 mul sodium hydroxide burns correlated with very low prostaglandin-like activity in the aqueous humor. The low prostaglandin-like activity probably resulted from alkaline hydrolysis of aqueous prostaglandins and massive cellular death in iris and ciliary body tissues.

Alkalies↗
PubMed1974

Nuclear magnetic resonance studies and water "ordering" in the crystalline lens.

Nuclear magnetic resonance studies of the relaxation times of the water in the crystalline lens show that, as in all interfacial systems, these parameters are markedly reduced from their values in pure water, that T(2) is less than T(1), and that both depend on water content. Determination of diffusion coefficients and studies on physiologically inert lenses indicate that reduced relaxation times do not provide direct evidence for ordering of the bulk of the cell water.

Animals↗