The VVR incidence rate was particularly high in women apheresis donors over 45 years old and increased with repeating cycles of apheresis. Smaller CBV, high sensitivity of low-pressure baroreceptors, and citrate effects on cardiovascular reflex might be major factors involved in the high incidence of VVRs.

The cells of Blepharisma which possess red pigment (blepharismin) show step‐up photophobic response (temporal ciliary reversal induced by a sudden increase in light intensity). Bleaching of the cells by cold shock raised a threshold light intensity for the response, Oxidation of red pigment that produced blue pigment did not raise the threshold for the response. The action spectrum for the step‐up photophobic response of the cells which possess normal red pigment had peaks at about 580, 540 and 490 nm, a value which coincided with peaks of an absorption spectrum of the red pigment. The absorption spectrum of oxidized pigment (blue pigment) shifted 20 nm toward infrared light. The action spectrum for the response of the cells which possess blue pigment also shifted 20 nm toward infrared light. Results suggest that red pigment might be involved in the step‐up photophobic response. Key words. Blepharismin, ciliary reversal, photoreceptors, photoresponse.

Abstract‐The red pigment granule of Belpharisma japonicum is believed to be a photoreceptor organelle mediating photodispersal. Freeze‐fracture and thin section electron microscopy revealed that the pigment granules contained a honeycomb‐like structure constructed of folded membranes. In the fracture face of the honeycomb‐like structure, small membrane particles were observed, which might correspond to pigment—protein complexes. The pigment granules were isolated and detergent‐solubilized. Sodium dodecyl sulfate‐polyacrylamide gel electrophoresis (SDS‐PAGE) showed that the pigment granules mainly contained a 200 kDa membrane protein. The complex of red pigment and 200 kDa protein was isolated by gel‐filtration chromatography of the detergent‐solubilized components, and the protein was subjected to SDS‐PAGE and amino acid analysis. The 200 kDa protein could not be dissociated into subunits by 2‐mercaptoethanol, indicating that the protein is composed of a single polypeptide chain. Hydrophobic amino acids contained in the 200 kDa protein were not dominant, suggesting that only partial domains may extend across the membrane of the honeycomb‐like structure.

A manual enzymatic method is described for sensitive fluorometric determination of uric acid in human serum. This method is based on an enzymatic reaction with uricase to form hydrogen peroxide from uric acid and the following oxidation of o-phenylenediamine with peroxidase and hydrogen peroxide for the production of a fluorescence compound. The specificity and the selectivity in the method are due to the uricase reaction and the fluorometry, respectively. The formed fluorescence in the reaction mixture is measured at 410 nm (an excitation) and 550 nm (an emission). This enzymatic method can determine uric acid at 30-1000 microM, with a between-assay relative standard deviation of 4.35% or less. A good correlation is obtained between the present method and the colorimetric kit method.