Vitreous Fluorophotometry in Three Models of Experimental Diabetes Mellitus

Ss, Smith; Fs, Ashburn; Ar, Pilkerton; Recant, Lillian

doi:10.1097/00006982-198200220-00009

Cited by 9 publications

(4 citation statements)

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“…Full pupillary dilatation is mandatory for proper VFP records. Previous studies reported the use of different combinations of medications, such as 2.5% phenylephrine and 1% cyclopentolate [5,16,18] or 2.5% phenylephrine with 1% tropicamide [19]. We found a combination of 1% cyclopentolate and 1% tropicamide to be most satisfactory for maximum and long-lasting pupillary dilatation.…”

Section: Discussionmentioning

confidence: 65%

“…The mortality rate was low (2 of 24) due to short duration of anesthesia and type of anesthetic used [5,6,13,18,22]. Although many sites have been tested for fluorescein injection (tail vein [20], femoral vein [6,19]), we found the external jugular vein to be the most accessible.…”

Section: Discussionmentioning

confidence: 79%

“…Smith et al [18] and Vine et al [20] showed that mid-vitreous fluorescein concentrations in rats with STZ induced diabetes were significantly lower than in normal rats. However, vitreous fluorescein concentrations, when compared with total plasma fluorescein concentration, was significantly increased for after two weeks of diabetes.…”

Section: Discussionmentioning

confidence: 99%

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Effect of piroxicam on the blood-retina barrier in experimentally induced diabetes in rats

et al. 1991

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The effect of piroxicam on the blood-retina barrier was evaluated in rats with experimentally induced diabetes. Diabetes was induced in rats by intraperitoneal injection of streptozocin (STZ). Diabetic rats were divided into two equal groups: those treated with piroxicam, a long-acting platelet inhibitor, and an untreated control group. Vitreous fluorophotometry (VFP) was performed both before and two weeks after induction of diabetes and piroxicam intake. Streptozocin-induced diabetes caused an alteration in the blood-retinal barrier evidenced by an increase in vitreous fluorescein concentration in diabetic rats compared with normal rats. Piroxicam intake did not lead to significant change in vitreous fluorescein concentrations. However, the examination had to be terminated at two weeks because of cataract formation. The piroxicam treated group showed less incidence of lens opacity formation (59.1% compared to 81.8% in the untreated group, p = 0.0006). Piroxicam administration appears to protect the diabetic rat eye against lens opacification.

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Section: Discussionmentioning

confidence: 65%

Section: Discussionmentioning

confidence: 79%

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Effect of piroxicam on the blood-retina barrier in experimentally induced diabetes in rats

et al. 1991

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“…As in studies on man, these studies yielded conflicting results. Elevated vitreous fluorescein levels [7,8] in diabetic rats which could be normalized by insulin treatment [9,10], as well as no differences between normal and diabetic rats, have been reported [11,12]. Technical difficulties [13,14] in measuring vitreous fluorescein levels in rats and biological factors [11,14] such as metabolic state and strain differences of the animals might have caused these inconsistent data.…”

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confidence: 99%

Vitreous fluorescein accumulation determined by in vivo fluorophotometry and by vitreous extraction in normal and diabetic rats

Kaufmann

Lacoste

1986

Diabetologia

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Summary.Vitreous fluorophotometry was performed on pigmented male rats (Piebald strain) 2 weeks after induction of diabetes by streptozotocin. In vivo fluorophotometry data were compared with measurements obtained by direct extraction of the vitreous 60 rain after an intravenous injection of sodium fluorescein. In addition, the rate of fluorescein disappearance from blood plasma, plasma protein binding of fluorescein and the effect of insulin treatment of diabetic animals were investigated. Age-matched nondiabetic animals served as controls. In vivo fluorophotometric measurements showed a good correlation with fluorescein determinations after direct extraction of the vitreous. Vitreous fluorescein concentrations were similar in diabetic and normal rats and were strongly related to the dye plasma levels within each group of animals. In the diabetic rats, however, the elimination of plasma fluorescein was accelerated and the percentage of free fluorescein, as determined by ultrafiltration and equilibrium dialysis, was consistently higher (130-150% of controls). The ratios of vitreous to total or free plasma fluorescein levels were elevated in diabetic rats. Experimental data indicate that plasma concentration of free fluorescein is crucial for vitreous dye accumulation. Insulin treatment of diabetic rats markedly improved their metabolic state and normalized the plasma fluorescein elimination and the vitreous to plasma fluorescein concentration ratios. It is concluded that vitreous fluorophotometry can be adequately applied to pigmented rats, provided that plasma fluorescein elimination rate and protein binding are considered in the interpretation of the results, since both influence the vitreous fluorescein accumulation and both may be altered by disease and drug treatment.Key words: Rat, streptozotocin diabetes, vitreous fluorophotometry, vitreous fluorescein extraction, insulin, fluorescein pharmacokinetics, fluorescein protein binding.Vitreous fluorophotometry, an in vivo method of assessing fluorescein levels in the vitreous body after a systemic application, was introduced some years ago in medical research. Ever since, several authors [1-3] have reported enhanced vitreous fluorescein concentrations in diabetic patients without angiographically detectable retinopathy. It was then suggested that elevated vitreous fluorescein levels may represent the earliest abnormality in developing diabetic retinopathy and indicate a breakdown of the blood retinal barrier. Tight metabolic control resulted in a normalization of the vitreous fluorophotometric readings [4]. Other groups have been unable to demonstrate any alteration between healthy and diabetic patients without observable retinopathy [5,6]. The technique was also applied to study the effect of experimentally induced diabetes by streptozotocin or pancreatectomy on the blood retinal barrier in rats. As in studies on man, these studies yielded conflicting results. Elevated vitreous fluorescein levels [7,8] in diabetic rats which could be normalized by insulin tre...

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