Detection and Determination of Porphobilinogen in Urine

Król, Sylwia; Rimington, C.; Tooth, B. E.

doi:10.3109/00365515609049281

Cited by 16 publications

(2 citation statements)

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“…The findings of & Scott (1959), who showed that labelled opsopyrrole dicarboxylic acid is not incorporated into porphyrin during biosynthesis, make unlikely any modification of this scheme whereby opsopyrrole dicarboxylic acid acts as an intermediate or as a cofactor of an isomerizing enzyme. Rimington (1955) has' pointed out' that the mechanism of the Corwin-Andrews reaction with formation of a tripyrromethane can apply only to the dipyrromethenes, not to the dipyrromethanes, an argument against the mechanisms proposed by Shemin (1955) and by Granick (1955 1959) There is practically no information on the biosynthesis of flavinadenine dinucleotide in plants. The available evidence relating to this process in animal tissues or micro-organisms is meagre, although the function of flavin nucleotides as components of respiratory enzymes has long been known.…”

Section: Discussionmentioning

confidence: 99%

The enzymic condensation of porphobilinogen to porphyrins

Lockwood

Benson

1960

Biochemical Journal

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is no correlation between anticholinesterase activity and effectiveness as reactivator. The ratios (potency as reactivator:reactivity with organophosphates), obtained with different oximes, support the interpretation that attachment to the phosphorylated enzyme during reactivation enhances activity. Possible sites of attachment are discussed. We wish to thank the Department of Scientific and Industrial Research for the special research grant to P. W.S., which has defrayed some of the cost of this work. We are also grateful to Miss M. E. Williams for her help.

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Section: Discussionmentioning

confidence: 99%

The enzymic condensation of porphobilinogen to porphyrins

Lockwood

Benson

1960

Biochemical Journal

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“…The withdrawal from the market of the Trace Õ PBG kit by Thermo Scientific has left a gap in the methodology for rapid urinary PBG analysis. Previously widely used qualitative methods such as the Watson-Schwartz test 18 the Rimington method 19 and the Hoesch test 20 are all simple procedures with a lower detection limit of approximately 12 mol/L. However, these methods have been criticized for low sensitivity and poor specificity 21,22 and EQA data from WEQAS showed that at a concentration of 10.7 mol/L (upper reference limit) the percentage assessed as positive was 40% vs. 80% positive using the Trace Õ PBG kit (WEQAS porphyrin guide).…”

Section: Methodsmentioning

confidence: 99%

Best practice guidelines on first-line laboratory testing for porphyria

et al. 2017

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The porphyrias are disorders of haem biosynthesis which present with acute neurovisceral attacks or disorders of sun-exposed skin. Acute attacks occur mainly in adults and comprise severe abdominal pain, nausea, vomiting, autonomic disturbance, central nervous system involvement and peripheral motor neuropathy. Cutaneous porphyrias can be acute or chronic presenting at various ages. Timely diagnosis depends on clinical suspicion leading to referral of appropriate samples for screening by reliable biochemical methods. All samples should be protected from light. Investigation for an acute attack: • Porphobilinogen (PBG) quantitation in a random urine sample collected during symptoms. Urine concentration must be assessed by measuring creatinine, and a repeat requested if urine creatinine <2 mmol/L. • Urgent porphobilinogen testing should be available within 24 h of sample receipt at the local laboratory. Urine porphyrin excretion (TUP) should subsequently be measured on this urine. • Urine porphobilinogen should be measured using a validated quantitative ion-exchange resin-based method or LC-MS. • Increased urine porphobilinogen excretion requires confirmatory testing and clinical advice from the National Acute Porphyria Service. • Identification of individual acute porphyrias requires analysis of urine, plasma and faecal porphyrins. Investigation for cutaneous porphyria: • An EDTA blood sample for plasma porphyrin fluorescence emission spectroscopy and random urine sample for TUP. • Whole blood for porphyrin analysis is essential to identify protoporphyria. • Faeces need only be collected, if first-line tests are positive or if clinical symptoms persist. Investigation for latent porphyria or family history: • Contact a specialist porphyria laboratory for advice. Clinical, family details are usually required.

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Acute Intermittent Porphyria

Watson¹

1961

JAMA

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THE TERM porphobilinogen (PBG) was introduced by Waldenstr\l=o"\mand Vahlquist 1 to designate the Ehrlich aldehyde-reacting chromogen which Sachs 2 first distinguished from urobilinogen and which characterizes the urine in cases of acute porphyria. The dominantly genetic character of acute intermittent porphyria, as well as its ease of confusion with many other diseases, the protection that may be offered by knowledge of precipitating factors, such as barbiturates, together with newer knowledge about therapy during relapse, emphasize the need of definitive diagnosis.Historical Background PBG was first crystallized by Westall3 and its monopyrrolic structure was soon elucidated by Cookson and Rimington.4 Subsequent studies have shown that it is an intermediary in heme biosynthesis, although not in evidence under normal circumstances and only rarely in diseases other than porphyria.In 1941 Watson and Schwartz 5 observed that the Ehrlich aldehyde compound of PBG is not extracted by chloroform, in contradistinction to that of urobilinogen, and pointed out that this difference was characteristic of urine samples from patients with acute porphyria. Hammond and Welcker 6 examined 1,000 samples from as many general hospital cases of all varieties and found no positive reactions by this simple method. This gave some indication of the relative infrequence of the reaction in diseases other than acute porphyria. Nevertheless, false-positive tests are at times observed and have given rise to incorrect diagnoses. Positive tests were reported by one of us (C. J. W.) in several cases of severe systemic disease in which there was nothing suggestive of acute porphyria,7 including Hodgkin's disease, hepatic cirrhosis, poliomyelitis, tetanus, cancer of the pancreas, carcinomatosis of the bone marrow, and intra-abdominal hemorrhage, as from a dissecting aneurysm.At the time these cases were studied, the nature of the Ehrlich reactor was not examined by additional methods such as will be discussed; hence, it is not certain that porphobilinogen itself was represented. Schwartz8a observed that the porphobilinogen aldehyde compound is not extracted by butanol, in contrast to certain other Ehrlich reactors not extracted by chloroform. This behavior has been observed both in human and experimental porphyria. Schwartz and co-workers8bl 8c found that in the urine of rabbits in the early stages of experimental porphyria, a substance yielding a butanol-soluble Ehrlich compound was often preponderant and later gave way to PBG itself. Normal rabbit urine at times contains a similar substance in small amounts. A similar Ehrlich reactor was observed, without PBG, in a patient with porphyria who developed volvulus of the cecum.9 The chromogen itself was extractible by ethyl acetate at pH 4.0 (acetic), quite unlike PBG. This behavior has also been well correlated in other instances in which butanol solubility of the aldehyde compound has been noted. There is reason to believe that a variety of substances, some as yet unidentified, may behave in this ...

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Detection and Determination of Porphobilinogen in Urine

Cited by 16 publications

References 15 publications

The enzymic condensation of porphobilinogen to porphyrins

The enzymic condensation of porphobilinogen to porphyrins

Best practice guidelines on first-line laboratory testing for porphyria

Acute Intermittent Porphyria

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