Characteristics of a protein error in determination of serum protein in the presence of inorganic salt.

There is a possibility that the color development of the dye-binding method based on a protein error of a pH indicator is affected by the coexisting inorganic salt. Thus, the author theoretically and experimentally investigated the effect of the inorganic salt on the protein error. In a theoretical analysis, the anion of an inorganic salt, like the dissociated dye and buffer anions, was assumed to react with the protein, forming a colorless anion-protein complex. The calculated results were compared with those obtained by experiments using three pH indicators and various kinds of inorganic salts. The calculated results obtained are as follows: (1) The color development decreases with increasing the concentration of the inorganic salt and the equilibrium constant of the reaction between the inorganic salt and protein; (2) The rate of the absorbance decrease is larger for a lower concentration of the inorganic salt than for a higher one; (3) The larger is the equilibrium constant, the larger is the absorbance decrease. The absorbance decrease was caused by the anion, and was increased by increasing the anion concentration. The magnitude of the effect of the anion was iodide > bromide > chloride, which was associated with their ionic radius. The difference in the effect of the anion was thought to indicate that the equilibrium constant, in other words, the bonding strength of the anion to protein is iodide > bromide > chloride.     

High-performance liquid chromatographic method for determining trichothecene mycotoxins by post-column fluorescence derivatization

The method described here is based on a separation of deoxynivalenol, nivalenol and fusarenon-X on a C18 column using aqueous acetonitrile, and successive post-column fluorescence derivatization involving an alkaline decomposition to form formaldehyde and modified Hantzsch reaction with methyl acetoacetate and ammonium acetate (lambda ex = 370 nm and lambda em = 460 nm). By this method, 5-10 ng of the standard trichothecenes could be determined. By employing a clean-up procedure with a florisil column and a Sep-Pak CN cartridge, 61.4-96.9% recoveries were obtained for deoxynivalenol and nivalenol added to corn, wheat and barley at concentration levels of 0.05-1 ppm.     

Relativistic time delays in the Dirac approach to nucleon-nucleus scattering

In connection with a characteristic feature of the effective optical potential in the Dirac approach two types of time delays are considered in the relativistic eikonal approximation. One is obtained from the scattering amplitude and the other given by the wave packet motion in the interaction region. These time delays turn out to differ in sign at intermediate energies, in contrast to the agreement between corresponding nonrelativistic time delays.     

Effect of pressure on the solubilities ofo-,m- andp-xylene in water

The solubilities of o-, m- and p-xylene in water were measured at 25.0°C up to 250, 385, and 50 MPa, respectively. The solubility increased with increasing pressure up to 120 MPa (50 MPa for p-xylene) and then decreased. The reaction volumes, V^o accompanying the dissolution at 0.1 MPa were estimated as –3.6±0.5, –3.4±0.5, and –4.1±0.5 cm³-mol^–1 for o-, m-, and p-xylene, respectively, from the pressure dependences of the solubilities. The limiting partial molar volumes, of p- and o-xylene in water under high pressure were estimated from V^o and the molar volume of the xylene. The partial molar volumes decreased with increasing pressure. The reaction volume for the formation of intra-molecular pairwise hydrophobic interaction between the methyl groups, as proposed by Ben-Naim, is discussed for the V^o of p- and o-xylene at 0.1 MPa.     

Inhibitory effects of non-steroidal anti-inflammatory drugs on superoxide generation.

Effects of non-steroidal anti-inflammatory drugs (NSAID: amfenac sodium, diclofenac sodium, indomethacin and ketoprofen) on the generation of superoxide anion (O2-) by isolated rat polymorphonuclear leukocytes (PMN) were studied spectrophotometrically using cytochrome c. The effects of these drugs were also studied on O2- production by the xanthine-xanthine oxidase and reduced nicotinamide adenine dinucleotide phosphate (NADPH)-NADPH oxidase systems. Amfenac sodium, at 0.1 mM, inhibited significantly O2- generation in rat PMN induced by opsonized zymosan. At 0.5 mM, diclofenac sodium and indomethacin inhibited the O2- generation in rat PMN. All of the above drugs slightly inhibited O2- production by the xanthine-xanthine oxidase system. On the other hand, O2- production by the NADPH-NADPH oxidase system was significantly inhibited by the addition of amfenac sodium, ketoprofen or indomethacin. These results suggest that non-steroidal anti-inflammatory drugs do not work as an O2- scavenger and block O2- production by the NADPH-NADPH oxidase system of rat PMN. It is concluded that amfenac sodium and the other drugs are able to inhibit granulocyte O2- production by blocking the activation of NADPH-oxidase.     

A facile synthesis of (−)-prostaglandin E1 via a three-component coupling process

A very short synthesis of chiral prostaglandin E₁ methyl ester is described.