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A technique is described for measuring the effect on the aqueous flow rate in man of drugs topically applied to one eye. Fluorescent measurements are taken from the treated and control eyes after both are stained with fluorescein by the corneal route. A mathematical treatment is developed which takes account only of the ratio of the measurements obtained from the two eyes. Subsidiary experiments with systematically administered fluorescein make it possible to assess changes in iris permeability induced by the drug; the mathematical treatment takes these changes into consideration in calculating the change in the flow rate. Six steroid reactors who reacted to Dexamethasone with a large rise in tension showed no change in flow rate. Five normal subjects showed a marked drop in flow on treatment with guanethidine. Iris permeability decreased with the steroid and increased with guanethidine. Experiments with pilocarpine gave uncertain results, showing the technique cannot be applied universally.

Publisher Summary Physical methods that have been employed in vitamin and hormone studies include: visible- and ultraviolet-absorption spectrophotometry, photochemical techniques, colorimetry, fluorescence spectroscopy, fluorophotometry, infrared and Raman spectroscopy, x-ray diffraction studies, manometric techniques, polarography, and isotopic tracer methods. Of these techniques, some have had limited application and others are not universally regarded as physical. As this chapter is limited to methods that are both essentially physical, and of broad application in the vitamin and hormone field, only the following topics are included: visible- and ultraviolet-absorption spectrophotometry, colorimetry, fluorescence spectroscopy, and fluorophotometry. It has not been practicable to consider all aspects of these techniques. In discussing colorimetry, for example, it has been necessary to omit reference to the many chemical problems concerned with the devising of color reactions and of procedures for eliminating interfering substances. In deciding what material to include and what to exclude, preference has been given to the quantitative and physical aspects of the methods discussed.

Two methods of determining the rate of loss of fluorescein from the aqueous humour in man are described. The dye is introduced into the cornea by means of iontophoresis and estimated in the eye with the slit-lamp fluorophotometer. In the first method the time course of the fluorescein concentration in the anterior chamber is observed, from which its turnover rate in the chamber is derived. In the second method measurements of the ratio of the total fluorescence of the eye to that of the aqueous humour lead to a direct evaluation of the aqueous flow rate. The errors and limitations of the methods are discussed and it is concluded that the second method, though generally more reliable, is inapplicable to blue-eyed subjects. In other cases there is good accordance between the results obtained by the two methods. In a small group of young normal volunteers the mean turnover rate found by the first method was 0·015 min and the mean rate of flow by the second method 2·5 μl/min.

Fluorescein arrival in each ocular fundus subsequent to intravenous injection was plotted simultaneously in humans by a fluorophotometric method. In 17 normal subjects arrival time was equal in the two eyes; the resultant dye dilution curves were symmetric in shape when simultaneous curves of right and left eyes were compared. In eight patients with proven unilateral carotid artery occlusion and ten others with probable unilateral carotid artery or ocular circulatory disease, there was either delay in arrival of dye to the affected eye or asymmetry of the resultant dye dilution curves. Potential diagnostic and investigative uses of this apparatus in the study of circulation are suggested.

Lysergic acid and clavine alkaloids in the extracts of 68 kinds of Convolvulaceae seeds were investigated by fluorophotometry, thin-layer chromatography, column chromatography and infrared spectrophotometry. Lysergic acid amide, isolysergic acid amide, lysergol and elymoclavine were identified as the alkaloidal components in nine morning glory seeds of horticultural varieties which were commercially available. The total alkaloid contents in these seeds determined by the colorimetric method with Van Urk reagent were 0.0003 to 0.0206% as lysergic acid amide.

労働科学 43巻 2 号（1967) J. Science of Labour Vol. 43, No. 2 UDC 613.63:543.4 有害物測定法（ 概論） 多田台＊ ON THE METHODS FOR THE DETERMINATION OF TOXIC SUBSTANCES IN AIR By Osamu TADA＊ In the control of toxic air contaminants in work places, it is most important to assess precisely the level of exposure of workers by appropriate method of air sampling. For such a purpose, there are required simple and rapid methods of sampling and chemical analysis, because the concentrations of toxic substances in the air are usually fluctuating in work places. Regarding the method of air sampling, especially, should be designed as adequate to the purpose of occupational health. In this paper are discussed the general principles for the methods of determining toxic substances in the air of work places and the choice of sampling devices for gas, fume and dust on the basis of results of some experiments, which were made on midget bubbler and midget impinger for gas and vapor, midget impinger and filter paper sampler for dust, mist and fume. Regarding the analytical methods, merits of colorimetry, ultraviolet spectrophotometry, fluorophotometry and flame-photometry are discussed from the view-point of practical use in industrial hygiene. -------------------------------------------------------------- 労働科学研究所・労働衛生学研究部・労働衛生学第1研究室 Lab. of Hygiene (I), Division of Hygiene, Institute for Science of Labour