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Biomedical subjects

E R Gordon

Publications and source records attributed to E R Gordon.

At least 55 records · Page 3Linked to original sources

Definition of a conjugation of dysfunction in Gilbert's syndrome: studies of the handling of bilirubin loads and of the pattern of bilirubin conjugates secreted in bile.

1. Intravenous doses of bilirubin (3.4 mumol/kg) were given to normal subjects and patients with Gilbert's syndrome. Both groups displayed an identical initial disappearance of a substantial proportion of the bilirubin but, late in time, the Gilbert's patients exhibited reduced clearance with a sustained elevation of the plasma bilirubin and no reflux into the plasma space of conjugated bilirubin. Increasing the dose in normal subjects (by factors of 3 and 6) failed to reproduce the response found in the Gilbert's patients. 2. In the the bile-containing duodenal aspirates of Gilbert's patients the average proportion of bilirubin found as bilirubin diglucuronide was 68% (normal 88%) and of bilirubin monoglucuronide, 23% (normal 7%). Both differences were significant at the P less than 0.001 level. In the Gilbert's patients restriction of caloric intake to 1569 kJ/day for 2 days characteristically raised the serum bilirbuin with no modification of the biliary pigment pattern; phenobarbital (180 mg/day for 2 weeks) decreased the plasma bilirubin to the normal range with, concomitantly, a reversion of the biliary pigment pattern towards normal. 3. We conclude that there is no hepatic uptake defect in Gilbert's syndrome but that there is decreased activity in the conjugation process underlying the addition of the second glucuronic acid moiety to bilirubin, to form bilirubin diglucuronide.

Adolescent↗

The isolation and further characterization of the bilirubin tetrapyrroles in bile-containing human duodenal juice and dog gall-bladder bile.

Bilirubin and its conjugates were extracted from either dog gall-bladder bile or bile-containing human duodenal juice into chloroform containing 10mm-tetraheptylammonium chloride. The intact bilirubin tetrapyrroles were then separated by t.l.c. Structural elucidation was made after coupling of the individual pigments with diazonium salts. Four azopigments were detected: azopigment alpha(o) or dipyrrolic azobilirubin; azopigment delta or dipyrrolic azobilirubin monoglucuronide; azopigment alpha(3) or dipyrrolic azobilirubin monoglucoside; and, from dog gall-bladder bile, azopigment alpha(2). The last conjugate required further verification of its structure. After methanolysis, it was shown by combined g.l.c.-mass spectrometry to contain xylose in a 1:1 molar ratio with the azopigments of bilirubin. Human bile contained 86% bilirubin diglucuronide, 7% bilirubin monoglucuronide monoglucoside diester, 4% bilirubin monoglucuronide and 3% bilirubin. Dog gall-bladder bile had a considerably different composition; it contained 47% bilirubin diglucuronide, 40% bilirubin monoglucuronide monoglucoside diester, 8% bilirubin monoglucuronide, 4% bilirubin diglucoside, 1-2% bilirubin and traces of conjugates containing xylose. The total bilirubin content and proportions of the conjugates did not change in bile that was frozen and stored at -20 degrees C under N(2), whereas in the chloroform/tetraheptylammonium chloride extract, similarly stored, total pigment was slowly lost and the diglucuronide conjugate converted into the monoglucuronide.

Animals↗

The isolation and characterization of bilirubin diglucuronide, the major bilirubin conjugate in dog and human bile.

The chemical structure of the major conjugate of bilirubin was unequivocally elucidated by structural analysis. The conjugated bilirubins were first separated from the lipid components of human duodenal aspirates or dog gall-bladder bile, and then resolved by t.l.c. into a series of tetrapyrroles. The major tetrapyrrole was then converted into its more stable dipyrrolic azo derivative for further analysis. The conjugated moiety of the azopigment was characterized after methanolysis with sodium methoxide. This reaction yields two types of product, those soluble in water and those soluble in organic solvents. The organic-soluble fraction was shown by t.l.c. and mass spectrometry to contain the methyl esters of the dipyrrolic azo derivatives of bilirubin. The water-soluble materials were analysed by enzymic procedures, t.l.c., n.m.r. spectrometry and combined g.l.c. and mass spectrometry. This analysis showed that the only water-soluble product resulting from the methanolysis was glucuronic acid. The structure was identical with that of pure standards, on both mass spectrometry and n.m.r. spectroscopy. No contaminating moieties were found. Quantitative measurement indicated that the glucuronic acid had been released in a 1:1 molar ratio with the resulting methyl esters of the dipyrrolic azo derivatives of bilirubin. This unequivocally establishes bilirubin diglucuronide as the major pigment present in bile. Past problems with identification of bilirubin diglucuronide were shown to originate from procedures which resulted in incomplete separation and isolation of the azopigments of the conjugated bilirubins, owing to contamination by biliary lipids.

Animals↗

Bilirubin secretion and conjujation in the Crigler-Najjar syndrome type II.

Features characteristic of the Crigler-Najjar syndrome (type II) are described in an adolescent boy with severe congenital unconjugated hyperbilirubinemia. Bilirubin encephalopathy developed only in early puberty after surgery and fasting, coincident with a dramatic rise in serum bilirubin, which responded to intensive therapy. Fasting was later shown to increase markedly the serum bilirubin levels and probably was a major factor in precipitating the initial acute event. One year later, while the patient was in a metabolic steady state, the secretion rate of bilirubin was measured by aduodenal marker-perfusion technique, and the nature of the secreted bilirubin conjugates was characterized. Total bilirubin secretion rates were low, 4.39 mg per hr and 4.44 mg per hr on two separate studies. The major pigment detected in bile was bilirubin monoglucuronide. Bilirubin diglucuronide comprised only a minor fraction of the pigments, and other conjugates were not detected. The present study documents a reduced biliary bilirubin secretion and suggests that the addition of the second glucuronic acid moiety to the bilirubin molecule may be defective in Crigler-Najjar syndrome (type II).

Adolescent↗

Herpes zoster in general practice.

Eighty-seven patients with the clinical diagnosis of herpes zoster were seen during a one-year period in eight general practices in Glasgow, the rate per 1,000 practice population being approximately 2.4. Of these, 78 (90 per cent) had serological evidence of active infection with herpes zoster. The anatomical location of the skin eruption was most common in the areas of the fifth cranial nerve, middle and lower trunk and thigh. A possible reactivating agent (trauma four, steroids two, irradiation one) was found in only seven patients. The illness as assessed by systemic upset and dissemination of lesions was generally not severe. Post-herpetic neuralgia was the most troublesome complication, found in 44 per cent of 64 patients revisisted 3-18 months after the acute illness.

Adult↗

The isolation of an azobilirubin beta-D-monoglucoside from dog gall-bladder bile.

An ethyl anthranilate azopigment of bilirubin conjugated to beta-d-monoglucoside was isolated from dog gall-bladder bile. Glucose was cleaved from the azopigment by treatment with beta-glucosidase and beta-glucuronidase. Mild alkaline hydrolysis of the compound by sodium methoxide yielded two kinds of compounds, water-soluble and organic-soluble. The former were shown, by enzymic analysis, t.l.c., nuclear magnetic resonance, and combined g.l.c. and mass spectrometry, to contain glucose. No evidence was obtained from these data that a disaccharide was present in this fraction. The organic-soluble compounds formed during this methanolysis were shown, by t.l.c. and mass spectrometry, to be the isomeric dipyrrole azopigments of bilirubin. These findings contribute further evidence to the controversy surrounding the nature of conjugated bilirubin.

Animals↗

Biochemical aspects associated with an ethanol-induced fatty liver.

Isocaloric replacement of either the fat or carbohydrate content of the diet by ethanol (36% of the total caloric intake) produced fatty infiltration of the liver in rats. The increase in hepatic triglyceride content was associated with a decrease in both ATP and glycogen contents. Increased activity of mitochondrial Mg(2+)-stimulated adenosine triphosphatase paralleled the increase in the free P(i) content of the liver homogenate. During the regression of the fatty liver, glycogen contents returned to normal within 24h of the removal of ethanol from the diet. Not until the third day after the withdrawal of ethanol had the Mg(2+)-stimulated adenosine triphosphatase activity and free P(i) content of the homogenate returned to normal. A slow regression of the triglyceride content from the liver occurred and by the fifth day both ATP and triglyceride concentrations had returned to the values observed in the rats given the liquid control diet.

Adenosine Triphosphatases↗