J. A. Van Best

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Autofluorescence (lambda = 530 nm) of the human lens was determined as a function of age by fluorophotometry in insulin-dependent diabetics and in healthy controls. Statistical analysis revealed a significant linear age dependency for both groups (7.98 ng eq X ml-1 y-1 for diabetic patients, P less than 0.001 and 6.36 ng eq X ml-1 y-1 for healthy controls,(More)
Lens transmission for blue-green light (lambda = 490 nm and 530 nm) was assessed by means of fluorophotometry in 67 diabetic patients without cataracts and compared with that of 52 healthy controls. Lens transmission was determined from peak autofluorescence values in the anterior and posterior parts of the lens, assuming an about equal fluorescence peak(More)
The photosensitizing properties of bacteriochlorin a (BCA), a nontoxic derivative of bacteriochlorophyll a, were investigated in vivo. BCA has an absorption band at a wavelength at which tissue penetration is optimal (760 nm), and it shows preferential tumor retention in Greene melanoma implanted in the anterior chamber of rabbit eyes. A dose of 20 mg/kg(More)
In EMG to force processing the force of a muscle or the corresponding muscle moment with respect to the joint is determined from EMG and muscle length by means of a model of the muscle's contractile and elastic properties. In kinetic analysis the joint moment is calculated from the ground reaction force and the positions and accelerations of the body(More)
Exposure to low-intensity white light can induce dysfunction of the blood-retinal barrier (BRB) at the retinal pigment epithelium (RPE). To determine whether the shorter wavelengths white light are responsible for this dysfunction, rabbit retinas were exposed to blue light (400-520 nm) or yellow light (510-740 nm). The permeability of the BRB, a parameter(More)
To assess the effect of glaucoma and timolol on tear secretion, basal tear turnover was measured with fluorophotometry in 13 open-angle glaucoma patients not using any ophthalmic medication, 24 patients using timolol medication daily, and 41 healthy control subjects. Basal tear turnover is defined as the tear turnover at the lowest level of reflex(More)
The metabolic disorder in diabetics often results in progressive retinopathy with severe visual impairment. Changes in metabolism can influence corneal autofluorescence. This has led to speculation that diabetic retinopathy might be associated with changes in corneal autofluorescence. Corneal autofluorescence of both eyes was determined by fluorophotometry(More)
A method for assessing the inward permeability of the blood-retinal barrier by fluorophotometry is presented. The permeability value is calculated with the fluorophotometer computer from fluorophotometric scan values in vitreous and non-protein-bound fluorescein concentration values in plasma. No diffusion coefficient of fluorescein in vitreous was required(More)
Aqueous flow in normal human eyes was assessed at 1 hr intervals via fluorophotometric measurements, starting 4 hr after fluorescein instillation. The average coefficients of variation of the individual flow values were 5.3% and 8.4% for 1 hr and 1 week intervals, respectively. Aqueous flow was measured in 11 healthy volunteers after the instillation of(More)
One of the inflammatory responses of the eye to local application of platelet-activating factor (PAF) is oedema of the conjunctiva, caused by extravasation of plasma. Aim of the study was to investigate if fluorescein would leak from the blood into the tears together with plasma protein after application of PAF to the eye. Fluorescein was given(More)