Determination microspectrophotometric

The second activation maximum for Echinocystis Factor I is approximately 30 mfi higher than that of gibberellic acid. The intensity of fluorescence is only about 3% that of gibberellic acid. Microspectrophotometric techniques for the determination of the acid equivalent weight (II) and of ethylenic double bonds (II) give a ratio of 0.75 double bond per acid equivalent in this fraction. 

M9. Matioli, G., Brody, S., and Thorell, B., Microspectrophotometric determination of differentially extracted haemoglobin in single erythrocytes. Acta Hematol. 28, 73-85 (1962). 

Figure 6. Rate of the glucose-6-phosphate dehydrogenase reaction as a function of the concentration of the substrate glucose-6-phosphate expressed in log-log coordinates. An isolated ascites cell (EL2) was impaled with a microelectrode, which then was used to electrophoretically inject known concentrations of the substrate into a localized region of the cell. The oxidatiorVreduction state of the cofactor to which the reaction is coupled was monitored by microspectrophotometric methods to determine the rate of the corresponding reaction in situ. (Replotted from the data of Kohen et al., 1973.)...

Chambers for oxygen consumption measurements are prepared from microscopic slides coated with a thin paraffin film. With a tip of a hypodermic needle held in a micromanipulator, a small round dent of 10—15 pm is made in the paraffin film, and a drop of 40% HF applied to the dent enables the formation of small circular cavities visible after the removal of paraffin. To increase the measuring capacity, an automatic cuvettechanging device has been developed. The object stage maintained at constant temperature by water circulation from a temperature controlled bath, is moved in six discrete steps by a synchronous motor. Thus, oxygen consumption in six different chambers can be assayed simultaneously. The basic equipment used for microspectrophotometric determinations of oxygen consumption does not differ essentially from the equipment used for other purposes, such as cytophotometry (Hamberger et al., 1975). 

S. WUlmann, A. Terenji, l.V. Yaroslavsky, T. Kahn, P. Hering, Determination of the optical properties of a human brain tumor using a new microspectrophotometric technique. Proc. SPIE 3598, 233 (1999)... 

Preliminary experiments in our laboratory have indicated a disturbance in the functional activity of splenic cells from pantothenic acid-deficient rats immunized with diphtheria toxoid. In studies conducted in collaboration with Dr. Abram Stavitsky it was shown that splenic cells from immunized pantothenic acid-deficient rats, in contrast to those from normal immunized rats, were unable to fabricate antibody when cultured in vitro or when passively transferred to normal rats. In co-operation with Dr. Cecile Leuchtenberger evidence was obtained that the mean deoxyribonucleic acid content of isolated splenic nuclei from immunized pantothenic acid-deficient rats was lower than that of comparable controls. Deoxyribonucleic acid was determined by microspectrophotometric analysis of the Feulgen reaction (Leuchtenberger et al, 1951). These results may be interpreted to mean that the deficiency interfered with the acceleration of cellular division which normally accompanies antibody production in the spleen. Since cellular division is always preceded by an increase in deoxyribonucleic acid content, the direct participation of pantothenic acid in deoxyribonucleic acid synthesis becomes an intriguing possibility. 

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