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Biomedical subjects

J De Jersey

Publications and source records attributed to J De Jersey.

At least 19 recordsLinked to original sources
PubMed1995

Studies on the reactivity of acyl glucuronides--VIII. Generation of an antiserum for the detection of diflunisal-modified proteins in diflunisal-dosed rats.

Acyl glucuronide metabolites of carboxylic drugs such as the salicylate derivative diflunisal (DF) have been shown to react with proteins to produce covalent adducts. To aid in the study of the formation and distribution of these adducts in both humans and rats, we raised an antiserum against human serum albumin modified by covalent attachment of DF via an amide bond, using a carbodiimide reagent. This antiserum had wide reactivity, reacting with all types of DF-modified proteins tested and with free DF (albeit at a lower affinity). It did not cross-react with other salicylates or other non-steroidal anti-inflammatory drugs. The antiserum has been used in immunoblotting to detect proteins covalently modified by DF in the plasma and livers of rats treated with the drug for 7 days. Although some cross-reactivity was apparent on the blots, a series of DF-modified proteins was found in cytosolic, mitochondrial and mixed membrane fractions of hepatocytes, with molecular weights ranging from 28 to 130 kDa.

Animals↗
PubMed1994

Anti-acetaldehyde adduct antibodies generated by ethanol-fed rats react with reduced and unreduced acetaldehyde-modified proteins.

We have previously shown that rats fed ethanol for prolonged periods generate antibodies reactive with proteins modified by acetaldehyde in vitro. In this report we demonstrate that these antibodies react with two groups of adducts: those formed when acetaldehyde reacts with proteins at 37 degrees C for 24 hr ('unreduced' adducts) and those formed by a 1 hr incubation followed by the addition of sodium cyanoborohydride (a reducing agent specific for Schiff bases) to the reaction mixture ('reduced' adducts). These data suggest that adducts from both of these groups are formed in vivo as a result of ethanol ingestion by rats.

Acetaldehyde↗
PubMed1994

Biosynthesis and possible pathological significance of fatty acid ethyl esters.

Fatty acid ethyl esters have been found in human and other animal tissues following alcohol consumption and may be involved in the pathology of alcohol abuse. In this review, current information on the biogenesis of fatty acid ethyl esters is considered and their potentially deleterious effects are discussed.

Acyltransferases↗
PubMed1993

Antibodies from alcoholics, ethanol-fed rats and a rabbit immunised with proteins modified by acetaldehyde in vitro react with liver cytosolic proteins from ethanol-fed rats.

In previous studies we have shown that ethanol-fed rats generate antibodies reactive with proteins modified by acetaldehyde in vitro and that their livers contain proteins modified by acetaldehyde. In this study we demonstrate that the antibodies from these animals react with the modified proteins found in their livers. Furthermore, when the antibodies reactive with specific proteins were isolated, they were found to react with all of the modified proteins detected by the whole serum. This suggests that all of the proteins modified by acetaldehyde in vivo carry the same or similar epitope(s). In addition, antibodies from alcoholics and a rabbit immunised with proteins modified by acetaldehyde in vitro also reacted with the liver cytosolic proteins from ethanol-fed rats. Therefore it appears that similar epitopes are generated in alcoholics as a result of ethanol misuse, in rat liver due to prolonged ethanol feeding and by the in vitro modification procedure used to produce the immunogen for the rabbit.

Acetaldehyde↗
PubMed1991

Acetaldehyde-modified proteins and associated antibodies in ethanol-fed rats.

Rats fed ethanol for periods of 3-27 months were found to produce an immune response to acetaldehyde-modified proteins, whereas treatment for a shorter period (3 weeks) did not lead to such a response. The antibodies from the ethanol-fed animals were shown to be reactive with a series of proteins modified by acetaldehyde in vitro. This suggests that reactivity towards the modified proteins is independent of the carrier protein, with antibodies being raised which interact solely with the acetaldehyde-containing adduct and not the protein itself. We have also been able to demonstrate the presence of modified proteins in the liver cytosol of these ethanol-fed rats. However, unlike previous reports which suggested that only one protein was modified, we found that many cytosolic proteins were modified. This suggests that the modification of proteins by acetaldehyde is less specific than was previously thought.

Acetaldehyde↗
PubMed1991

Alcohol abusers exhibit a higher IgA response to acetaldehyde-modified proteins.

In the present study we have used an enzyme-linked immunosorbent assay to measure the immunoreactivity towards acetaldehyde-modified proteins in plasma from alcoholics, patients with non-alcoholic liver disease and control social drinkers. All three groups showed a response to modified proteins when total immunoglobulin binding was measured. However, when the assay was modified such that class-specific immunoglobulin binding was measured, it was found that the alcoholic response had a significantly greater immunoglobulin A component than patients with non-alcoholic liver disease or controls who were social drinkers. Thus measurement of IgA binding to acetaldehyde-modified proteins may be a marker for alcohol abuse.

Acetaldehyde↗
PubMed1990

Antibodies against acetaldehyde-modified epitopes: presence in alcoholic, non-alcoholic liver disease and control subjects.

Several studies have recently shown the presence of antibodies against acetaldehyde-modifications in the sera of alcoholic patients. To assess the specificity of this immune response, plasma immunoreactivity with proteins modified in vitro by acetaldehyde was measured using an enzyme-linked immunosorbent assay in 97 alcoholic patients with varying degrees of alcoholic liver disease, in 35 patients with non-alcoholic liver diseases and in 33 control subjects who were social drinkers. All three groups showed some response against acetaldehyde-modified epitopes. The highest plasma reactivities were found in alcoholics, especially those with steatosis and alcoholic hepatitis. Plasma from patients with non-alcoholic liver disease and control subjects also reacted with the acetaldehyde conjugates, but to a lesser extent than plasma from alcoholics. The reliability of these antibodies as markers of either alcohol abuse or alcoholic liver disease therefore appears to be low. However, further studies using more precisely modified proteins or elucidation of the classes of immunoglobulin involved in the immune response against the modified proteins may give clearer differences between the three groups.

Acetaldehyde↗
PubMed1989

Biospecific interactions: their quantitative characterization and use for solute purification.

Biospecificity is due largely to the formation and dissociation of non-covalent complexes between small molecules and macromolecules, or between two macromolecules. The first part of this review is concerned with the use of such biospecificity in the fractionation and identification of solutes. Major emphasis is given to affinity chromatography, especially in regard to the practical considerations inherent in an experimental situation and to the wide range of specific interactions that can be utilized. The second part of the review considers the quantitative characterization of biospecific complex formation. The merits of frontal gel chromatography, electrophoretic methods and affinity chromatography are discussed, and special consideration is given to the effects of ligand and/or acceptor multivalency because of its relevance to many biospecific interactions. Finally attention is drawn to the feasibility of employing quantitative affinity chromatographic theory for the determination of association constants for antigen-antibody systems by radioimmunoassay and enzyme-linked immunosorbent assay techniques.

Biochemistry↗
PubMed1989

Amino acid sequence of a crystalline seed albumin (winged bean albumin-1) from Psophocarpus tetragonolobus (L.) DC. Sequence similarity with Kunitz-type seed inhibitors and 7S storage globulins.

The complete amino acid sequence of winged bean albumin-1 (WBA-1) of Psophocarpus tetragonolobus (L.) DC has been determined. The protein consists of a single polypeptide chain of 175 amino acid residues, with one disulfide bond, corresponding to a molecular mass of 19333 Da. WBA-1 was found to be homologous with the Kunitz-type seed trypsin inhibitors. The similarity between WBA-1 and the trypsin inhibitors from soybean and winged bean was 38% and 28%, respectively; similarity was most marked in the C-terminal third of the sequence with identities of 47% and 37%, respectively. Significant similarity was found also between the 2S Kunitz-type proteins and the carboxy-terminal region of the 7S storage globulins, suggesting that these two groups of proteins are related and may have evolved from a common ancestral precursor. Circular dichroism measurements suggest a high content of beta sheet (52%) while secondary structure predictions based on amino acid sequence indicate a similar content and distribution of beta sheet to that found for soybean trypsin inhibitor by X-ray diffraction studies.

Albumins↗
PubMed1989

Ethanol induces the production of antibodies to acetaldehyde-modified epitopes in rats.

Rats treated with ethanol for periods of 3-27 months were found to produce an immune response to acetaldehyde-modified proteins, whereas treatment for a shorter period (3 weeks) did not lead to such a response. The reactivity towards the modified proteins was shown to be independent of the carrier protein as antibodies were reactive with modified human plasma proteins and modified bovine haemoglobin. The data presented here support the hypothesis that acetaldehyde-modified proteins may act as neoantigens in alcoholics and may play a role in the aetiology of alcoholic liver disease.

Acetaldehyde↗
PubMed1987

Effects of acetaldehyde on polymerization of microtubule proteins.

The in vitro effects of ethanol and acetaldehyde on polymerization of calf brain microtubular proteins (MTP) were examined. While ethanol up to 100 mM had no effect on the polymerization of MTP, acetaldehyde above 0.5 mM had an inhibitory effect. This effect was not dependent on the presence of microtubule-associated proteins (MAPs), since acetaldehyde had a similar effect on the polymerization of highly purified tubulin. Electron microscopy revealed that the number and the length of microtubules at equilibrium was reduced by the presence of acetaldehyde. Acetaldehyde raised the critical concentration for tubulin assembly and caused greater inhibition at lower tubulin concentrations. Acetaldehyde augmented the depolymerizing effects of Ca2+ on preassembled microtubules. In addition, acetaldehyde itself caused depolymerization of microtubules but only in the absence of MAPs. Long-term (19.5 h) incubation of MTP with acetaldehyde led to significant loss of polymerization ability which could not be reversed by removal of acetaldehyde. This loss of activity was apparently independent of the observed formation of reducible adducts between acetaldehyde and MTP.

Acetaldehyde↗
PubMed1984

Enzymatically active zinc, copper and mercury derivatives of the one-iron form of pig allantoic fluid acid phosphatase.

Derivatives of the violet, iron-containing acid phosphatase of pig allantoic fluid have been prepared in which one of the two iron atoms present in the native enzyme has been replaced by zinc, copper or mercury. The derivatives so formed are enzymatically active: the Zn-Fe, Cu-Fe and Hg-Fe enzymes have specific activities of about 80%, 25% and 17% respectively, of the maximum specific activity of the Fe-Fe enzyme in the standard assay at pH 4.9 with p-nitrophenyl phosphate as substrate. In contrast to the Fe-Fe enzyme, the mixed metal derivatives are not rapidly inactivated by H2O2. Visible absorption spectra of the derivatives confirm that all of the visible absorption of the Fe-Fe enzyme is due to one of the iron atoms. Attempts to prepare an active Cu-Cu enzyme were unsuccessful.

Acid Phosphatase↗
PubMed1983

Mössbauer and EPR study of the binuclear iron centre in purple acid phosphatase.

Mössbauer spectra have been determined on 57Fe-enriched samples of both pink (reduced) and purple (oxidized) forms of pig allantoic acid phosphatase (EC 3.1.3.2), and EPR spectra on corresponding unenriched samples. The spectra show unambiguously that both forms of the enzyme contain two distinct, antiferromagnetically coupled, high-spin iron atoms: a ferrous-ferric ion pair in the pink, reduced form, and a pair of ferric ions in the purple, oxidized form.

Acid Phosphatase↗
PubMed1981

Lanthanide probes in biological systems: characterization of luminescence excitation spectra of terbium complexes with proteins.

Upon irradiation in the ultraviolet region aromatic chromophores may transfer energy to a nearby Tb3+, which in turn emits a green phosphorescence. This paper reports the characterization of the ultraviolet excitation spectra of aromatic chromophores capable of transferring energy to Tb3+ by monitoring of the green Tb3+ emission in the 540-550 nm region. Results are included for complexes containing phenyl, hydroxyphenyl, indole, and catechol chromophores. Characteristic excitation spectra are presented for the aromatic chromophores occurring as side chains in proteins. Though it is preferable to compare entire excitation spectra, the ratio of intensities at 292 to 276 nm, R, is suggested as a useful diagnostic criterion. Numerical R valves are indicative of the following aromatic side chains as the energy donor to Tb3+: R less than 0.2, unionized tyrosine; R = 0.5 to 1.0, tryptophan; and R less than 1.8, ionized tyrosine. The phenylalanyl chromophore displays a definitive excitation spectrum at shorter wavelengths. For ovotransferrin R = 0.9 and comparison of the full excitation spectra suggests that it contains comparable contributions from both ionized tyrosine and tryptophan side chains. Some difficulties in obtaining reliable excitation spectra are described. An analysis of inner-filtering of incident light reveals that for an absorbance less than 0.8 the excitation spectrum is broadened and flattened compared to the absorption spectrum. At maximum absorbances greater than 0.8 false maxima may appear to both sides of a real maximum. Two spurious maxima in an excitation spectrum were generated in a Tb3+ complex and compared to the correct excitation spectrum of the same complex obtained at lower absorbance.

Animals↗
PubMed1975

Organophosphate inhibitors: the reactions of bis(p-nitrophenyl) methyl phosphate with liver carboxylesterases and alpha-chymotrypsin.

Bis(p-nitrophenyl) methyl phosphate (BNMP) has been tested as a spectrophotometric titrant for a group of serine hydrolases. Bis(p-nitrophenyl) methyl phosphate reacts rapidly with liver carboxylesterases from chicken, sheep, and horse, and more slowly with alpha-chymotrypsin, releasing 2 mol of p-nitrophenol per active site titrated, and producing a phosphorylated enzyme very stable to dephosphorylation. However, pig liver carboxylesterase produces 2.2 mol of p-nitrophenol per active site titratedmreaction of pig and chicken liver carboxylesterases with bis(p-nitrophenyl) [3H]methyl [32P]phosphate clarified this differencemone molecule of the chicken enzyme reacts with one molecule of bis(p-nitrophenyl) methyl phosphate, releasing both p-nitrophenol residues, and resulting in an inhibited enzyme with one phosphorus atom and one methyl group covalently bound. Pig enzyme reacts rapidly, forming (presumably) methyl p-nitrophenyl phosphoryl-carboxylesterasemthis further reacts, concurrently producing methyl phosphoryl-carboxylesterase plus p-nitrophenol, or free enzyme plus methyl p-nitrophenyl phosphate, in the ratio of about 5 : 1 at pH 7.55. The free enzyme produced undergoes further reaction with bis(p-nitrophenyl) methyl phosphate until all the carboxylesterase is inhibited.

Animals↗