Search PubMed⌕ Search

Biomedical subjects

D E Gaasterland

Publications and source records attributed to D E Gaasterland.

48 records · Page 3Linked to original sources
PubMed1978

Ah locus: genetic differences in susceptibility to cataracts induced by acetaminophen.

The Ahb/Ahb homozygous and the Ahb/Ahd heterozygous inbred mouse strains from the (C57BL/6)(DBA/2)F1 X DBA/2 backcross are genetically responsive to 3-methylcholanthrene. They both also develop, within 6 hours after a large intraperitoneal dose of acetaminophen, an irreversible opacity in the anterior portion of the lens. Such cataract formation does not occur in similarly treated nonresponsive inbred strains or nonresponsive Ahd/Ahd individuals from the same backcross. Differences in acetaminophen metabolism and toxicity are associated with the Ah locus in the mouse, and differences in heritability at the Ah locus exist in the human. Our ophthalmologic findings may be important clinically to certain patients receiving either a single large overdose of this drug or high doses over a long period.

Acetaminophen↗
PubMed1978

Accuracy of aqueous humor flow determination by fluorophotometry.

After corneal iontophoresis of fluorescein, freshly enucleated rhesus monkey eyes were perfused at a known rate with glutathione-bicarbonate-Ringer's solution. Total fluorescein mass and aqueous fluorescein concentration were measured with a fluorophotometer every 15 min for 6 to 8 hr. The aqueous flow was calculated from the fluorophotometry data by the second method of Jones and Maurice. This flow was then compared to the known perfusion rate. The curve for total fluorescence decay was not precisely parallel to the curve for aqueous fluorescence decay. This affected the value of the ratio of total:aqueous fluorescence. The most accurate and consistent flow values were obtained with the decay constant from the aqueous fluorescence decay curve combined with the ratio of total:aqueous fluorescence extrapolated back to zero time. Under these two conditions, the calculated flow in five experiments was 5.4% +/- 3.3 (+/- S.D.) lower than the known flow. The 99% confidence interval of the true mean percent difference between the known and calculated flows is--12% to +1%. A small effect of corneal fluorescein concentration on measured aqueous fluorescence was observed.

Animals↗
PubMed1978

Perfusate effects upon resistance to aqueous humor outflow in the rhesus monkey eye. A comparison of glutathione-bicarbonate Ringer's solution to pooled aqueous humor as perfusate.

In vivo perfusion of the anterior chamber of normal rhesus monkeys with pooled rhesus aqueous humor gives an initial total facility of 0.48 +/- 0.08 (+/-S.E.) microliter/min/mm Hg. With continued intermittent perfusion for 2 hr this value increased only slightly to 0.57 +/- 0.10 microliter/min/mm Hg. Perfusion of the paired eyes of the same monkeys with glutathionebicarbonate Ringer's solution gives an initial total facility of 0.55 +/- 0.08 microliter/min/mm Hg. This value increased to 1.21 +/- 0.15 microliter/min/mm Hg with continued intermittent perfusion. Thus aqueous is a satisfactory perfusate for experiments requiring prolonged stability of the eye, but glutathione-bicarbonate Ringer's solution is not a satisfactory substitute perfusate. Neither addition of physiologic amounts of ascorbic acid to the buffered salt solution nor careful modification of the pH of the solution to the physiologic level prevented the increase of total facility it produces when used as a perfusate. A reversible, fast-phased small-magnitude increase in total facility was noted in eyes perfused with either perfusate. It is speculated this is caused by neural mechanisms for intraocular pressure control.

Animals↗
PubMed1977

Uveoscleral aqueous outflow in the rhesus monkey: importance of uveal reabsorption.

The uveal absorption of aqueous humor at two different intraocular pressures was measured in rhesus monkeys by sampling vortex vein blood during anterior chamber perfusion of Ringer's solution containing both fluorescein and 125I albumin. At 20 mm. Hg, an excess of fluorescein equivalent in amount to 0.45 microliter/min. of anterior chamber perfusate and an excess of 125I albumin equivalent to 0.18 microliter/min. of perfusate was found in the vortex vein blood compared to systemic blood. At 32 mm. Hg, an excess of 0.86 microliter/min. of fluorescein and 0.26 microliter/min. of 125I albumin was measured. The increase in fluorescein absorption at the higher intraocular pressure was significant (0.025 less than p less than 0.05), with a uveal outflow facility of 0.034 microliter/min./mm. Hg. At an intraocular pressure of 20 mm. Hg, uveal aqueous outflow is less than 10% of total aqueous outflow. The pressure dependence of the uveal uptake of fluorescein implies an aqueous reabsorption into the uveal vessels by ultrafiltration. Uveoscleral aqueous "outflow" appears to consist of intraocular uveal reabsorption of water and small molecules from the aqueous, with only larger molecules like albumin actually leaving the eye through posterior scleral vessel perforations. This reabsorption plays a minor role in intraocular pressure regulation under normal conditions.

Absorption↗