Detection of human leucocytes by cyclic voltammetry and its application to monitoring of allergic reaction

Cyclic voltammetry was applied to the detection of human leucocytes and the monitoring of allergic reactions. A basal plane pyrolytic graphite electrode with attached leucocytes on a porous nitrocellulose membrane filter was employed as a working electrode. An anodic peak current appeared at 0.33 V versus the saturated calomel electrode (SCE) when the potential of the working electrode was scanned in the range of 0-1.0 V versus SCE. This peak current was attributed to the electrochemical oxidation of serotonin. When egg white was added to leucocytes obtained from patients who were allergic to egg, the peak current decreased owing to degranulation of leucocytes leading to serotonin release. The peak current decreased with increasing allergen concentration in the range of 5-50 micrograms ml-1. Leucocytes did not respond to other allergens such as soybean, milk and dinitrophenylated bovine serum albumin (DNP-BSA).     

Efficient acetic acid production by repeated fed-batch fermentation using two fermentors

Summary In acetic acid fermentation, the number of viable cells decrease as the acetic acid concentration increases to more than about 40 g/l, which means that the productivity attainable by conventional fed-batch and repeated fed-batch operations using one fermentor is limited. In this paper, based on a fed-batch experiment using Acetobacter aceti 2096, a mathematical model was developed. The optimization carried out showed the superiority of repeated fed-batch operation using two fermentors. The performance evaluation was made with respect to productivity and product concentration. It was shown to be attractive in practice to use multiple fermentors, in particular for high product concentrations. Experiments were then conducted to ascertain the simulation results. Offprint requests to: T. Kobayashi     

Study on the retrogradation of starch. I. Particle size and its distribution of amylose retrograded from aqueous solutions

The morphological features of amylose precipitates, especially the particle size and size distribution, during retrogradation have been investigated using scanning electron microscopy. It was found that the retrograded amyloses consisted of particles with a surprising uniformity in size, and the volume of each particle increased proportionally with the degree of retrogradation. These facts suggest that the retrogradation of amylose proceeds via a nucleation process, which is complete within a short time after the onset of retrogradation; this is then followed by growth of the nuclei. It was also found that, at a given percentage of retrogradation, the particle volume increased with increasing concentration of KCl in the solution. It was, therefore, considered that the reduction in the rate of retrogradation induced by KCl may be attributed to a decrease in the number of nuclei produced in the initial stage.     

Structure and expression of human thrombomodulin, a thrombin receptor on endothelium acting as a cofactor for protein C activation.

We have deduced the entire 575-amino acid sequence of the human thrombomodulin precursor from cDNA clones. The precursor starts with an 18-residue signal peptide domain, followed by the NH2-terminal domain, a domain with six epidermal growth factor-like structures, an O-glycosylation site-rich domain, a 24-residue transmembrane domain and a cytoplasmic domain. Simian COS cells transfected with the expression vector pSV2 containing thrombomodulin cDNA synthesized immunoreactive and functionally active thrombomodulin.     

Formation of anti-plant viral protein by Mirabilis jalapa L. cells in suspension culture

The extract of Mirabilis jalapa cultured cells and its precipitate fraction with 90% saturated ammonium sulfate showed an anti-plant viral activity comparable to that of the roots and leaves of the original plant. In the immunodiffusion experiment, the extract of cultured cells positively reacted with MAP (Mirabilis Anti-plant viral Protein) anti-serum. The changes in MAP formation during cell growth and the MAP content of roots and leaves were examined using enzyme-linked immunosorbent assay (ELISA). MAP formation proceeded almost in parallel with cell growth. The MAP content of cultured cells reached the highest level (0.6 mg/g dry weight) on the 9th day after inoculation, which was less than one-third of the content of the roots but three times larger than that of the leaves.Abbreviations MAP Mirabilis anti-plant viral protein - TMV tobacco mosaic virus - 2,4-D 2,4-dichlorophenoxyacetic acid - ELISA enzyme-linked immunosorbent assay Studies on the production of anti-plant viral substances of higher plant cells in suspension culture. Part 1     

A Combined Stain for Identifying Epithelial Cells of the Gastric Mucosa

New techniques are proposed for differentiating each type of gastric epithelial cell in the same tissue section. The techniques combine the following stains: A) paradoxical concanavalin A staining (PCS) to identify mucous neck cells, B) periodic acid Schiff-concana-valin A staining to distinguish mucous neck cells from surface mucous cells, and C) a modified Bowie's stain to demonstrate zymogen granules of chief cells. Feulgen hydrolysis preceding the Bowie stain was found to remove most of the nonspecific coloration encountered with the original Bowie method. The results obtained by the new sequences were as follows: 1) Feulgen hydroIysis-PCS-Bowie staining: mucous neck cells stained brown and chief cell zymogen granules deep blue. The other mucin-secreting cells remained unstained; 2) Feulgen hydrolysis-PAS-concanavalin A-Bowic staining: mucous neck cells stained brown, zymogen granules stained deep blue to purplish blue and surface mucous cells stained purplish red.     

Effects of low magnesium diet on the vascular prostaglandin and fatty acid metabolism in rats

Deficiency of magnesium with cardiovascular effects is thought to be related to alterations in the biosynthesis of prostaglandins (PGs) in the vasculature. Measurements were made of the PGE2, 6-keto-PGF1 alpha and thromboxane B2 (TxB2) outflow from the perfused isolated mesenteric arterial bed and the fatty acid composition of the tissue in rats maintained for 14 weeks on a low magnesium (LMg) diet. The serum Mg levels were significantly decreased and the serum Ca levels were significantly increased in the LMg group as compared to the controls. The arachidonic acid concentration in the triacylglyceride fraction was significantly increased in the LMg group. Long chain polyunsaturates such as 22:4n6 and 22:6n3 were consistently increased in the LMg rats as compared to the controls in both the phospholipid and triglyceride fractions as previously reported in other tissues. The PGE2, 6-keto-PGF1 alpha and TxB2 outflows were significantly increased in the LMg group as compared to the controls. These findings suggest that the biosynthesis of eicosanoids, mainly PGI2, is stimulated in Mg deficiency, and this may provide protection against intracellular Mg depletion and Ca accumulation, so as to counteract to the constricted and hyperreactive state of the vasculature in such a condition.     

Stimulatory effect of vanadate on hyaluronic acid synthesis in mesothelial cells from rabbit pericardium

Vanadate dose-dependently stimulated the incorporation of [3H]glucosamine into glycosaminoglycan, especially hyaluronic acid, in mesothelial cells from rabbit pericardium. The activity of hyaluronic acid synthase in the mesothelial cells treated with 50 microM vanadate for 0.5-1 h was stimulated to a level about 2 times over that of the control. Neither DNA synthesis nor protein synthesis in the mesothelial cells under the same experimental conditions was affected. The enhancement of the activity of hyaluronic acid synthase in the mesothelial cells treated with vanadate (50 microM) was not inhibited by the addition of cycloheximide (1 microgram/ml). These results suggest that vanadate stimulates the hyaluronic acid synthesis by activation of hyaluronic acid synthase in mesothelial cells from rabbit pericardium.