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Biomedical subjects

T W Jordan

Publications and source records attributed to T W Jordan.

29 records · Page 2Linked to original sources
PubMed1982

Is Percoll innocuous to cells?

Peritoneal macrophages from mice, isolated rat liver Kupffer cells and rat testis Leydig cells ingested large numbers of Percoll particles, a gradient medium widely used for separation of cells and subcellular organelles by density-gradient centrifugation. A decrease in the percentage of macrophages adhering to plastic also occurred after exposure of the cells to Percoll, even at 4 degrees C, a temperature at which Percoll was not ingested. The effect of Percoll on macrophage adherence may involve a loose association between the density medium and the cell surface. Other cell-surface-related phenomena may also be affected by prior exposure of cells to Percoll.

Animals↗
PubMed1981

Subcellular distribution of hepatic bile acid-conjugating enzymes.

1. The subcellular location of enzymes conjugating bile acids with glycine or taurine was investigated by centrifugation of rat liver homogenates. 2. [14C]Cholic acid-conjugating activity was predominantly associated with the soluble-microsomal region of the gradient after centrifugation in a Ti-15 zonal rotor but the bulk of the conjugating activity sedimented with mitochondrial-lysosomal fractions in differential pelleting experiments. 3. Cholate: CoA ligase (EC 6.2.1.7) and cholyltransferase (EC 2.3.1) were not enriched in purified Golgi or plasma-membrane fractions. Cholate: CoA ligase was distributed evenly between rough- and smooth-surfaced microsomal subfractions but cholyltransferase showed a dual soluble-rough microsomal activity distribution. 4. Sedimentation of cholyltransferase in mitochondria-enriched fractions prepared by differential centrifugation appears to be an artefact of sedimentation of rough microsomal membranes in mitochondrial fractions. 5. The subcellular distribution of bile acid-conjugating enzymes is discussed with reference to hepatic processing of bile acids.

Acyltransferases↗
PubMed1981

Inhibition of housefly oxidative detoxication by phthaleins, fluoresceins and related compounds.

1. Phenolphthalein, halogenated fluoresceins, and other triphenylmethane and diphenylmethane derivatives inhibited biphenyl hydroxylation, aldrin epoxidation and several O-dealkylations in insect abdomen homogenates. Phenolphthalein and eosin (50 muM) were 2-3 times more effective than SKF 525-A and piperonyl butoxide (50 muM) as inhibitors of biphenyl hydroxylation in vitro. 2. The phthaleins, Aurin and Aluminon, inhibited both epoxidation and hydroxylation to similar extents, but fluoresceins, Rhodamine B, Malachite Green, and basic diphenylmethane derivatives preferentially inhibited hydroxylation. 3. Tetrabromophenolphthalein ethyl ester and bis-(N-dimethyl-4-aminophenyl-methane inhibited biphenyl hydroxylation in vivo. Bis-(N-dimethyl-4-aminophenyl) methane synergized the toxic effects of 1-naphthyl N-methylcarbamate in live houseflies.

Abdomen↗
PubMed1980

The 4-methylumbelliferone sulphate sulphatases of human tears.

The properties of human tear 4-methylumbelliferone sulphate sulphatase (EC 3.1.6.1) have been investigated. More than 80% of the enzyme activity behaved as the acidic A isoenzyme on isoelectric focusing and DEAE-cellulose ion exchange chromatography. The distribution of enzyme activity in a normal population has been investigated. The least interindividual variation was seen when enzyme activities were calculated as units per mg tears. The alpha-galactosidase, beta-N-acetylglucosaminidase and sulphatase enzyme activities in human tears varied independently of each other. The use of tear sulphatases for the detection of metachromatic leukodystrophy (McKusick 24980) is discussed.

Acetylglucosaminidase↗
PubMed1977

Enzymic detection of metachromatic leukodystrophy patients and heterozygotes.

Two unrelated families with metachromatic leukodystrophy have been examined for the leukocyte enzyme arylsufatase A. The enzyme activities clearly reflect an autosomal recessive mode of inherence. All four parents showed heterozygote enzyme levels 40-60 percent of the control range while the two affected children had less than 20 percent normal activity. The two sibs of one affected child were shown to be heterozygote carriers. A simple screening method for sulfatase activity in tears has been developed which distinguished between metachromatic leukodystrophy patients and a control population which included other neurological disorders. Enzyme screening on tears may also be used to detect other lysosomal storage diseases including Tay-Sachs and Fabry disease.

Adult↗
PubMed1976

Pharmacokinetics of indoramin in man.

1 The fate of oral and intravenous indoramin has been studied after single doses in man using the 14C labelled drug. Plasma concentrations of indoramin have been determined during chronic oral antihypertensive therapy employing a stable isotope dilution assay. 2 Following singleoral dosing the drug is well absorbed and extensively metabolised. Faecal excretion in 72 h accounts for 46% of the administered radioactivity of which approximately 4% is associated with indoramin. Less than 2% of the radioactivity in urine is accountable as the concentration of total metabolites. Peak plasma levels both of drug and metabolites occur 1-2 h after dosing, the maximal lowering of blood pressure occurring at this time. 3 The clearance of indoramin, determined after intravenous administration is of the same order as liver blood flow. In the isolated perfused rat liver, the extraction ratio is 0.98.

Administration, Oral↗
PubMed1970

Detoxications in peripatus. Sulphate, phosphate and histidine conjugations.

Phenols were detoxified in the Onycophoran Peripatoides novaezealandiae by conjugation with sulphuric acid and phosphoric acid, but no evidence for a glycoside detoxication could be found. [(14)C]Benzoic acid was metabolized in 24h to N(2)-benzoyl-l-histidine, which was identified by electrophoresis, chromatography and dilution analysis. Similar conjugates were formed with p-aminobenzoic acid and p-nitrobenzoic acid. In longer-duration experiments further unidentified metabolites were formed, two of which appeared to result from the further metabolism of the histidine conjugate.

Aminobenzoates↗
PubMedDate not supplied

Antibody to liver membrane antigens in chronic active hepatitis. IV. Exclusion of specific reactivity to polypeptides and glycolipids by immunoblotting.

The reactivity of sera was examined in patients with autoimmune chronic active hepatitis and other liver diseases by immunoblotting. Polypeptides and glycolipids of liver plasma membrane, liver-specific lipoprotein and kidney membrane were separated and probed with sera from patients and from a rabbit immunized with mouse liver plasma membrane. Chronic active hepatitis sera reacted with a number of polypeptides in the liver plasma membrane preparations; similar but weaker reactivity was observed with sera from patients with other diseases and in some healthy subjects. Chronic active hepatitis sera did not react with glycolipids from liver plasma membrane. The immune rabbit serum reacted with two polypeptides of 180 kd present in liver plasma membrane but absent from kidney membrane, with two polypeptides of 50 kd which were nonliver-specific but species-specific, and with three major glycolipid components of liver plasma membrane: this reactivity thus differed markedly from that of the chronic active hepatitis sera. In studies using dot-blotting, it was found that solubilization of liver plasma membrane in detergents resulted in a marked reduction of the reactivity to liver plasma membrane of chronic active hepatitis sera, but little change in the reactivity of the chronic active hepatitis and other sera with liver-specific lipoprotein by immunoblotting indicated that liver-specific lipoprotein consisted of constituents of liver plasma membrane together with intracellular proteins.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗