Katsumi Sumida

Mutagenicity from ozonation of humic substances

Eight structural components of humic substances were ozonated. Mutagenic activity was found using TA100 with and without S9 mix for all ozonated components. p-Hydroxybenzaldehyde was chosen as an important component and ozonation products were determined by gas chromatography-mass spectrometry (GC-MS). Aldehydes, ketones and carboxylic acids were identified as the ozonation products. Among these products, acetaldehyde, formaldehyde, glyoxal, methylglyoxal and glyoxylic acid were recognized to be mutagenic. Furthermore, p-hydroxybenzaldehyde was first ozonated and then chlorinated. A great variety of chlorinated organic compounds, many of which are known mutagens, have been identified by GC-MS in the ether extract. The same compounds have previously been reported as chlorination products of humic substances. Aldehydic products by ozonation were identified from ozonation followed by chlorination of humic substances and p-hydroxybenzaldehyde.

Aldehydes as mutagens formed by ozonation of humic substances

Humic substances and p-hydroxybenzaldehyde, one of their components, were ozonated and quantitative analysis of the mutagenic aldehydes (formaldehyde, acetaldehyde, glyoxal, glyoxylic acid and methylglyoxal) was performed. Glyoxal and glyoxylic acid were the main mutagenic compounds. The ozone-treated solutions were flowed through a granular activated carbon (GAC) column and the KMnO4 consumed of the effluent decreased to about 40-50%. Most of the aldehydes formed by ozonation reduced, but glyoxal increased.

Mutagenicity of the components of ozonated humic substance

Eight components of humic substances were ozonated. Mutagenic activity was found with TA100 with and without S9 mix for all ozonated components. Ozonated products of p-hydroxybenzaldehyde were separated into five fractions by silica gel chromatography and each fraction subjected to mutagenicity assay. Mutagenic activity was found in the chloroform and chloroform-acetone (1:1) fractions. The compounds in these fractions were identified, and aldehydes such as formaldehyde, acetaldehyde, glyoxal, glyoxylic acid and methyl glyoxal were found to be mutagenic. Mutagenic compounds are present in the polar fraction.

Sequence-dependent antitumor effect of VP-16 and 1-β-d-arabinofuranosylcytosine in L1210 ascites tumor

The sequence-dependence of the antitumor effect of etoposide (VP-16) and 1-beta-D-arabinofuranosylcytosine (ara-C) was investigated against the L1210 ascites tumor in BDF1 mice. Treatment with VP16 (7.5 or 15 mg/kg) and ara-C (25 or 500 mg/kg) was administered intraperitoneally on days 1, 4 and 7 after tumor inoculation. Six hour pretreatment with 15 mg/kg VP16 followed by 500 mg/kg ara-C yielded a 100% cure rate, but only a 20% cure rate was obtained with the reverse sequence. Simultaneous administration of 15 mg/kg of VP-16 and 500 mg/kg ara-C interacted synergistically, producing a 70% cure rate. In contrast with the results obtained with VP-16 and 500 mg/kg ara-C, simultaneous administration of 25 mg/kg ara-C neither antagonized nor potentiated the antitumor effect of VP-16. Twenty-five mg/kg ara-C was too low to produce any antitumor effect with VP-16 in simultaneous administration. At every dose investigated, pretreatment with VP-16 followed by ara-C was the most effective antitumor schedule in L1210 leukemia. This sequence of drug administration did not cause greater toxicity as measured by weight loss or toxic death.

ENHANCED INCORPORATION OF 1-BETA -D-ARABINOFURANOSYLCYTOSINE BY PRETREATMENT WITH ETOPOSIDE

We examined the effects of timing of administration of etoposide on cytosine arabinoside (ara-C) incorporation into DNA in L1210 ascites tumor. At 1 hr after injection of ara-C, 3-hr and 6-hr pretreatments with 15 mg/kg of etoposide increased ara-C incorporation to more than 200% as compared to that of ara-C given alone. Simultaneous administration of etoposide, however, decreased ara-C incorporation to 33% of that of ara-C alone. These results might explain the previously reported sequence dependency of the antitumor effect of etoposide and ara-C.

Mutagenicity of ozonation and chlorination products from p-hydroxybenzaldehyde

p-Hydroxybenzaldehyde, a component of soil humic substances, was ozonated and chlorinated. The ether extract and the residue were subjected to the Ames assay; mutagenic activities were identified. The non-ionic resin CSP800 and the anion exchange resin CHPA25 were used for separation of mutagenic compounds. The compounds in the water layer were not adsorbed on CSP800 or CHPA25 and exhibited strong mutagenic activity. Mutagenic activity was reduced as the added chlorine was increased. Ether extracts were analyzed by gas chromatography-mass spectrometry (GC-MS) and chloral, 1,3-dichloro-2-propanone, 1,2,3-trichloro-1-propene, tetrachloroethylene and 1,1,1,3,3-pentachloro-2-propanone were identified as mutagenic compounds.

Effects of 5-fluorouracil and a combination of tegafur and uracil (UFT) on nucleotide metabolism in L1210 ascites tumor.

Changes in the deoxyribonucleotide pools following a single oral administration of 13 mg/kg of 5-fluorouracil (5-FU) or of 64.8 mg/kg of UFT (a mixed compound of tegafur and uracil) were investigated. We compared their pharmacodynamics and effects on nucleotide metabolism in L1210 ascites tumor on day 3 after intraperitoneal tumor inoculation. The intracellular dTTP pool decreased to half the control level 1-6 hr after the administration of 5-FU. The dTTP pools rapidly recovered after 6 hr. In contrast, UFT kept the intracellular dTTP level to 1/3 to 1/2 of the control level for 24 hr. Either drug elevated the intracellular dATP pools, but decreased dCTP pools. UFT influenced the intracellular dATP and dCTP levels longer than 5-FU. Orally administered UFT seemed to exert a longer and more potent inhibitory effect on thymidylate synthetase than equimolar 5-FU. In view of these results, we suggest that UFT could be a more potent chemotherapeutic drug than 5-FU in oral administration.

Some studies on the determination of indicator transition and its use in the titration of weak basic samples

Abstract In the titration of a weak basic sample, especially in the dilute solution, the transition color of the indicator is not sharp at the equivalence point. In order to avoid the indicator error, the color transition near the equivalence point must be known accurately. The color transition of an acid-base indicator can be calculated from complementary tristimulus data. To ensure accuracy, however, the chemical stoichiometric relationships about the acid-base equilibria are considered. A general expression for determination of the equivalence point is presented and factors influencing the titration are discussed.

Compatibility of Sodium Ampicillin for Injection on Its Mixture with Other Drugs

The potency of ampicillin is known to be reduced when mixed with glutathione. Halogen or sulfonic acid group is related to the detoxication mechanism of Tathion. In this study, mixtures were prepared first by dissolving Tathion in halogen -or sulfonic acid groupcontaining injections such as Allergin, Metilon and Adona.Then the effect of Viccillin for injection, an ampicillin preparation, added to the mixtures, was examined by bioassay and colorimetry. It was found that the potency of Viccillin is well preserved by adding Allergin, Metilon or Adona mixed with Tathion.

Determination of Hexestrol in Ointment by High-pressure Liquid Chromatography

High-pressure liquid chromatography (HLC) was evaluated in determination of hexestrol in ointment. Sample ointments were mixed with ethanol and isooctane. Hexestrol in the Hexron ointment was extracted into ethanol layer. Butyl p-hydroxybenozate was used as the internal standard. HLC was performed under the following conditions: model, Shimadzu LC-2F; detector, UV visible spectrophotomer Shimadzu SPD-1; wave length, 280nm; column, Permaphase ODS (2.1φ×0.5m); mobile phase, gradient elution system, 10% to 40% MeOH in H2O at 3% min; flow rate, 1 ml/min (at room temperature). The calibration curve was traced by plotting the ratio of the peak weight against the amount of each hexestrol. Satisfactory linearity was observed in the range of 0.125 to 1μg and quantitative determination was found to be possible. Other components in the Hexron ointment did not interfere in determination of hexestrol in this method. Hexestrol in the Hexron ointment was recovered at the rate 94% on an average by ethanol extraction. The quantitative determination of hexestrol in an ointment by HLC was carried out simply and rapidly.