Richard D. Batt

Quantitative analysis of sulfolipid (sulfoquinovosyl diglyceride) and galactolipids (monogalactosyl and digalactosyl diglycerides) in plant tissues.

Abstract A method has been developed for the quantitative and rapid estimation of sulfolipid and galactolipids in plant tissues. The procedure is based on the isolation of pure glycolipids by a combination of DEAE-cellulose column and thin-layer chromatography. The sugar component is estimated by the reaction of the lipid on the thin-layer adsorbent with phenol and sulfuric acid. Alternatively, the lipid is deacylated on the adsorbent in 2 N sulfuric acid and an aliquot of the hydrolyzate is reacted with phenol and sulfuric acid. Very small amounts of sulfo- and galacto-lipids can be reproducibly estimated by this method.

Intracellular localisation and properties of aldehyde dehydrogenases from sheep liver

Abstract 1. 1. The distribution of aldehyde dehydrogenases in sheep liver was studied. Activity was found in the cytoplasm, mitochondria and microsomes. 2. 2. Cross-contamination of activities from different subcellular fractions, during the isolation procedures used, was shown to be insignificant. Accordingly, the level of aldehyde dehydrogenase activity found in each fraction should reflect the distribution pattern in vivo. 3. 3. Aldehyde dehydrogenases from the cytoplasm and mitochondria were isolated and some of their catalytic properties examined. The results show that the enzymes from the two fractions are not identical.

Acetaldehyde formation during deproteinization of human blood samples containing ethanol.

Abstract Production of acetaldehyde during deproteinization of ethanol-containing human blood with perchloric acid has been studied using a semiautomated acetaldehyde assay based on vapor-phase transfer followed by enzymic oxidation and fluorimetry. Results obtained compare well with and extend those obtained in similar studies which have used gas chromatography as the method of acetaldehyde analysis. The extent of acetaldehyde production was variable but was related to blood ethanol concentration and could be decreased by increasing the dilution of the blood with the deproteinizing solution. Thiourea (25 m m ) was found to have no effect on the acetaldehyde production, and insignificant quantities of acetaldehyde were formed during deproteinization of plasma in the presence of ethanol. It is suggested that more than 90% of the acetaldehyde produced during processing of ethanol-containing human blood for assay originates from reactions occurring when blood cells, as distinct from plasma, are treated with a deproteinizing agent.

Stability of acetaldehyde in human blood samples

Abstract Acetaldehyde was found to disappear rapidly in human venous blood samples when added in concentrations ranging from 10 to 50 μ m . The disappearance was dependent on temperature and the presence of blood cells. Evidence is presented for the conversion of acetaldehyde to acetate. By contrast, acetaldehyde which accumulates in human venous blood samples from the metabolism of ethanol in vivo did not disappear under conditions where added acetaldehyde disappeared rapidly. It is suggested that acetaldehyde formed from ethanol in vivo may be bound reversibly to blood constituents.

Determination of acetaldehyde in blood using automated distillation and fluorometry

Abstract A sensitive enzymic method for the determination of acetaldehyde in human blood has been developed. The method may be operated in a semiautomated or fully automated mode and involves continuous-flow distillation of samples with fluorometry. Levels of acetaldehyde between 0.5 and 20 μmol/liter in blood may be determined, using either yeast or sheep liver aldehyde dehydrogenases.

Factors influencing rates of ethanol oxidation in isolated rat hepatocytes

The stimulation of ethanol oxidation by fructose which has frequently been observed in isolated hepatocytes was found to occur only in unsupplemented cells. In the presence of other substrates (lactate, pyruvate) which accelerate ethanol oxidation, fructose had no additional effect. Acceleration of ethanol oxidation by fructose was not directly related to the ATP demand created by fructose. The effects of fructose on ethanol oxidation rates were not due to changes in acetaldehyde concentration. In cells from fed animals, acetaldehyde concentrations rose as high as 200 microM in some incubations, and therefore became a significant factor limiting ethanol oxidation rates. In hepatocytes isolated from starved rats incubated with pyruvate, where acetaldehyde concentrations were very low, (1-2 microM) it was possible to assess the effect of changes in [lactate]/[pyruvate] (and hence free cytosolic NADH) on rates of ethanol oxidation. The results showed that the increase in free cytosolic [NADH] usually found during ethanol oxidation in vivo would inhibit rates of ethanol clearance by a maximum of 20%.

Acetaldehyde and Acetate Production during Ethanol Metabolism in Perfused Rat Liver

It has been reported that, in isolated perfused liver metabolizing 16 or 32 mM ethanol, as much as 60% of acetaldehyde formed from ethanol left the liver unmetabolized (Lindros et al., 1972). Krebs (1969) found that sufficient acetaldehyde was formed during perfusion with 10 mM ethanol to bring the alcohol dehydrogenase reaction into equilibrium. By contrast, Williamson et al. (1969) found that only trace amounts of acetaldehyde were released by livers metabolising 10 mM ethanol. Eriksson et al. (1975) have claculated that, in vivo, less that 5% of acetaldehyde formed from ethanol leaves the liver un-metabolized. This is so even in the presence of ethanol concentrations as high as 50 μmol/g wet wt. liver (Eriksson and Sippel, 1977).

A new method for the assay of glycolytic activity with special reference to microorganisms.

Abstract The method described provides a rapid and accurate assay of glycolytic activity by simultaneously measuring the rates of glucose utilization and lactate formation (plus other anionic products) in a single operation. The assay involves the separation of lactate-C 14 (plus other anionic products) from nonfermented glucose-U-C 14 by ascending chromatography on DEAE-cellulose paper with deionized water as solvent. Papers were dried and the portions containing lactate-C 14 and glucose-C 14 were cut out and counted separately using a liquid scintillation spectrometer. The sensitivity of the assay can be increased by increasing the specific activity of the glucose-C 14 substrate and the assay was at least as efficient as conventional methods. In nongrowing buffer suspensions of Streptococcus lactis , glucose-U-C 14 was fermented at a linear rate proportional to bacterial density.

Acetaldehyde Levels in Peripheral Venous Blood and Breath of Human Volunteers

If the extrahepatic metabolism of acetaldehyde in humans is similar to that which occurs in rats (1-6), venous blood acetaldehyde concentrations may not reflect those in potentially sensitive organs such as the brain. It is important to obtain estimates of the levels of acetaldehyde in blood (a) leaving the liver, in order to determine the maximum toxic potential of acetaldehyde, and (b) presented to the brain, since current theories proposing a role for acetaldehyde in the development of addiction to ethanol involve its interaction with components of the central nervous system (7,8).

Effects of ethanol treatment and castration on liver alcohol dehydrogenase activity

Induction of alcohol dehydrogenase (ADH) activity by chronic ethanol treatment and castration has previously been reported to occur in Sprague-Dawley rats. In the present study, no induction was found following chronic ethanol treatment and only a low level of induction was found with castration. However the activity of ADH was high in control animals compared with those used in other studies. The activity of ADH in control animals was not decreased by testosterone administration, which has been shown to reverse induction of the enzyme produced by chronic ethanol treatment or castration in other studies. It is concluded that the male Sprague-Dawley rat is not necessarily a suitable animal for the study of ADH induction by chronic ethanol treatment and that further unknown factors must be identified before the regulation of ADH activity in vivo is fully understood.