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Biomedical subjects

J D Priddle

Publications and source records attributed to J D Priddle.

34 records · Page 2Linked to original sources
PubMed1987

Effects of olsalazine in the jejunum of the rat.

Olsalazine (ADS) is the azo-linked dimer of 5-aminosalicylic acid (5-ASA). It is of value for the management of patients with ulcerative colitis but may be associated with increasing diarrhoea in a few. This study examines the effect of 5-ASA and ADS on small intestinal transport systems of the rat. Krebs-Ringer-bicarbonate solution was circulated through the lumen of a jejunal segment and the appearance of fluid, glucose and lactate on the serosal surface was shown to be linear over a two hour period. Addition of 5-ASA (10 mmol/l) or ADS (5 mmol/l and 10 mmol/l) caused a significant inhibition both of fluid transport (p less than 0.001), and of the appearance of glucose (p less than 0.001) and lactate (p less than 0.001 for 5 mmol/l and 10 mmol/l ADS, p less than 0.01 for 10 mmol/l 5-ASA). The uptake of glucose by rings of rat jejunum was shown to be markedly reduced by ADS. Experiments substituting glucose with either sucrose of 2-aminoisobutyric acid showed that ADS (5 mmol/l, 10 mmol/l) also inhibited the serosal appearance of fructose and the amino acid. These results show that 5-ASA and ADS, at concentrations which could be expected in the jejunum of patients receiving therapeutic doses, are able to inhibit small intestinal transport systems. The resulting increase in load on the diseased colon could be important for the pathogenesis of diarrhoea.

Aminoisobutyric Acids↗
PubMed1987

Cellular hypersensitivity to gluten derived peptides in coeliac disease.

Wheat gluten derived antigens have been tested for their ability to inhibit the migration of leucocytes from healthy subjects and patients with coeliac disease. Three preparations of a water soluble fraction (Frazer's fraction III, FIII) of partial peptic tryptic digests of wheat gluten had different effects in a direct (one stage) assay. Subfractions B and B2 caused migration inhibition of leucocytes from patients with treated coeliac disease but not of leucocytes from healthy volunteers or patients with Crohn's disease or ulcerative colitis. This migration inhibition seems to be specific for gluten fractions because maize zein fraction B, beta-lactoglobulin and ovalbumin did not cause it. The sensitivity of coeliac leucocytes to fraction B is not related to factors present in coeliac serum as the migration of leucocytes from healthy individuals preincubated with coeliac sera was not inhibited. Puromycin diminished inhibition by fraction B, which was active at 1.2 micrograms/ml in an indirect (two stage) migration inhibition assay; this is consistent with a process involving elaboration of lymphokine(s). More highly purified fractions of B2, P1-P4 were prepared by reverse phase high performance liquid chromatography (HPLC) and showed differing potency in direct and indirect assays, with P4 being the most active fraction. Inhibition of migration by gluten derived peptides appears to result from the release of lymphokine by leucocytes specifically from coeliac patients.

Antigens↗
PubMed1985

Antigenic reactivity of peptides derived from wheat gluten with sera from patients with coeliac disease.

Fraction B from a peptic-tryptic digest of gluten from Scout 66 wheat has already been shown to cause histological damage to the jejunal mucosa of coeliac patients. Peptide fractions, designated P1-P4, have been prepared from it by a combination of gel filtration (producing an intermediate fraction pseudo-B2: psi B2) and reverse-phase high pressure liquid chromatography. An enzyme-linked immunosorbent assay (ELISA) has been used to measure IgG antibodies to fraction B in sera from untreated coeliac patients, patients with inflammatory bowel disease (IBD) and healthy individuals. The coeliac group had significantly higher (P less than 0.05) antibody levels to fraction B than either of the control groups [medians: coeliac disease (n = 21), 0.247; IBD (n = 17) 0.019; healthy controls (n = 13) 0.020]. Five coeliac sera which gave high absorbance values in the ELISA were chosen and preincubated with fraction B in a range of concentrations, before assay by ELISA: a dose-dependent inhibition of binding was found. Two sera which gave high ELISA values were preincubated with fractions B2 and P1-P4. B2, P1, P2 and P4 gave a dose-dependent inhibition, with P1 being the most potent. Absolute values were different for the two sera but the same relative pattern of reactivity was observed for each. With the serum giving the higher ELISA value the concentration of fraction (microgram/ml) giving a 50% inhibition of binding when 0.5 ml was added to 0.5 ml of a 1/500 dilution of the serum (IC50) was 2.6 for fraction B, 61 for P1, 155 for B2 and 285 and 295 for P4 and P2 respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Antigen-Antibody Reactions↗
PubMed1984

The preparation of human intrinsic factor-cobalamin complex from human gastric juice by immunoadsorption.

Immune complexes of human intrinsic factor were prepared by mixing gastric juice saturated with vitamin B12, and sera from patients with pernicious anaemia that had a high proportion of binding (Type II) antibody. The complexes were isolated by sodium sulphate precipitation followed by Sephadex G-150 gel filtration. Acid conditions dissociated the immune complexes and allowed separation of specific antibody and purified antigen bound to vitamin B12 by Sephadex G-200 gel filtration. Specific antibody was covalently attached to Protein A Sepharose CL-4B by coupling with water soluble carbodiimide which allowed intrinsic factor-B12 complex to be purified directly from gastric juice. The intrinsic factor obtained after iodination, ran as a single band on SDS-polyacrylamide gel electrophoresis and was biologically active.

Anemia, Pernicious↗
PubMed1984

Heterogeneity of rat TCGF defined by Mono P isoelectric focusing.

Interleukin-2 (IL-2) prepared from Con A-activated rat spleen cells was partially purified using hydroxylapatite chromatography (HTP) and chromatofocusing on Mono P. IL-2 eluted in a major peak between 0.1 and 0.25 M NaCl in PBS (purification factor 36-fold) and in a second peak in the high salt elution (purification factor 5-fold). When analysed on Mono P, the major peak was found to resolve into four components with apparent pI values in the range of 7.05-5.80; further activity eluted in the high salt fraction. Similar patterns were observed using high salt eluted activity with minor variations in the apparent pI values. Neuraminidase treatment caused a shift in IL-2 charge towards more basic pI values. This analysis of the multiple species of IL-2 suggests that part of the heterogeneity may be due to variation in the degree of sialylation of the peptide chain.

Animals↗
PubMed1983

Development of a gas chromatography mass spectrometry assay for the two eosinophil chemotactic factors of anaphylaxis.

Gas chromatography mass spectrometry has been used for over a decade for the determination of the amino acid sequences of fragment peptides derived from larger parent molecules. The majority of these fragments have from four to seven residues and several different methods of derivatization have been devised. Few reports have been published in which similar techniques have been used for the quantification of such peptides, but there is a growing list of small peptides which have been shown to have biological activity in their own right. This report is concerned with the development of a gas chromatographic mass spectrometric assay for the two eosinophil chemotactic peptides, Val-Gly-Ser-Glu and Ala-Gly-Ser-Glu, which appear to have a role to play in the course of the inflammatory process in skin disorders.

Anaphylaxis↗
PubMed1980

A mass-spectrometric method for the estimation of the ratio of gamma-carboxyglutamic acid to glutamic acid at specific sites in proteins. Application to the N-terminal region of bovine prothrombin.

When a polypeptide containing gamma-carboxyglutamic acid is decarboxylated in 2H2O, residue of (gamma gamma-2H2)glutamic acid are formed. Subsequent proteolytic digestion produces peptides which contain at each site 2H2-substituted and unsubstituted glutamic acid in the same ratio as existed for gramma-carboxy-substitution. The peptides may be identified and this ratio determined by combined gas chromatography--mass spectrometry. We also discuss decarboxylation in 3H2O followed by amino-acid analysis and Edman degradation.

1-Carboxyglutamic Acid↗
PubMed1976

The separation and sequencing of permethylated peptides by mass spectrometry directly coupled to gas-liquid chromatography.

The use of g.l.c. coupled to mass spectrometry to separate and sequence permethylated acetyl- and trifluoroacetyl-peptides in a single operation is described. Both electron impact and chemical ionization were used to induce fragmentation, and the latter was found to be more sensitive. Chromatographic retention data are presented which suggest that peptide derivatives of molecular weight of at least 750 are accessible to the technique. The application of our methods to the determination of the primary sequence of proteins is discussed.

Chromatography, Gas↗
PubMed1974

Studies on the subunit structure and amino acid sequence of trisoe phosphate isomerase from chicken breast muscle.

1. Triose phosphate isomerase was prepared by chromatography on DEAE-cellulose of an (NH(4))(2)SO(4) fraction of an extract of homogenized chicken breast muscle. The product is homogeneous on gel electrophoresis and is suitable for growing crystals for X-ray work. The specific activity is 10000 units/mg and the value for E(0.1%) (280) is 1.20. 2. Comparison between the sum of the amino acid compositions of the tryptic peptides of the protein and the amino acid composition obtained on total hydrolysis of the protein indicates that the relative subunit mass is about 27000. 3. These data, together with the results of the examination of the amino acid compositions of a number of minor peptides, the number of peptides in the tryptic digest and the complete amino acid sequences of the tryptic peptides (the determination of which is described here), give no indication that the subunits are dissimilar. 4. A tentative amino acid sequence is presented for the protein, in which the ordering of the tryptic peptides is derived by homology with the sequence of the rabbit muscle enzyme (Corran & Waley, 1973). 5. An appendix describes the use that was made of mass spectrometry in the determination of some of the sequences. Mass-spectrometric data have been obtained for 35 residues, that is about 15% of the total sequence of the protein. 6. An extended version of the present paper has been deposited as Supplementary Publication SUP 50025 at the British Library, Lending Division (formerly the National Lending Library for Science and Technology), Boston Spa, Yorks. LS23 7BQ, U.K., from whom copies may be obtained on the terms given in Biochem. J. (1973) 131, 5.

Amino Acid Sequence↗
PubMed1972

Active-site labelling of triose phosphate isomerase. The reaction of bromohydroxyacetone phosphate with a unique glutamic acid residue and the migration of the label to tyrosine.

Triose phosphate isomerase from chicken muscle reacts stoicheiometrically with the active-site-directed irreversible inhibitor bromohydroxyacetone phosphate with concomitant loss of all catalytic activity. The primary site of attachment has been shown to be a unique glutamic acid residue in the sequence Ala-Tyr-Glu-Pro-Val-Trp. Unless the inhibitor-enzyme bond is stabilized by reduction of the C-2 carbonyl group with borohydride, the phosphate group is lost and the label migrates to the adjacent tyrosine residue. It is suggested that the gamma-carboxylate group of the glutamic acid residue may be the base responsible for primary proton abstraction from substrate in the catalysis. The failure of this reagent specifically to inactivate either muscle or yeast aldolase, and the use of the reagent in preparing isomerase-free glycolytic enzymes, is discussed.

Acetone↗