PubMed Health⌕ Search

Biomedical subjects

G G Thompson

Publications and source records attributed to G G Thompson.

At least 91 records · Page 5Linked to original sources
PubMed1977

Alterations in the activity of enzymes of haem biosynthesis in lead poisoning and acute hepatic prophyria.

1. The activities of six of the enzymes of haem biosynthesis have been assayed in peripheral blood from patients with lead poisoning, acute intermittent porphyria or hereditary coproprophyria. 2. Compared with normal subjects the lead-poisoned subjects had highly significant depression of delta-aminolaevulinate dehydratase, coproporphyrinogen oxidase and ferrochelatase. 3. Lead-poisoned subjects had highly significant elevation of delta-aminolaevulinate synthase activity. 4. delta-Aminolaevulinate synthase activity was inversely related to the haemoglobin concentration. 5. Increased delta-aminolaevulinate synthase and decreased delta-aminolaevulinate dehydratase activity are also found in acute intermittent porphyria. 6. Increased delta-aminolaevulinate synthase, normal prophobilinogen deaminase and uroporphyrinogen decarboxylase and decreased coproporphyrinogen oxidase are found in both lead poisoning and hereditary coproporphyria. 7. These enzyme changes explain the recognized patterns of porphyrins and prophyrin precurosrs in blood and urine in these conditions.

5-Aminolevulinate Synthetase↗
PubMed1977

The treatment of acute intermittent porphyria with laevulose.

1. The activities of the enzymes of haem biosynthesis were studied in 23 patients with acute intermittent porphyria. The mitochondrial enzymes delta-aminolaevulinate synthase, coproporphyrinogen oxidase and ferrochelatase were measured in leucocytes and the cytosolic enzymes delta-aminolaevulinate dehydratase, porphobilinogen deaminase and uroporphyrinogen decarboxylase in erythrocytes. 2. Leucocyte delta-aminolaevulinate synthase activity was elevated (P less than 0-001), with marked diminution of porphobilinogen deaminase activity (P less than 0-001) and reduction in the activities of delta-aminolaevulinate dehydratase (P less than 0-01) and uroporphyrinogen decarboxylase (P less than 0-005). 3. A therapeutic regimen based on intravenous laevulose infusion was studied. In four patients in acute attack and one in remission laevulose treatment was associated with a fall in delta-aminolaevulinate synthase activity, a rise in porphobilinogen deaminase and uroporphyrinogen decarboxylase activities, and a fall in urinary prophyrin precursor excretion (P less than 0-001). These studies provide a basis for the evaluation of the use of sugars in acute intermittent porphyria.

5-Aminolevulinate Synthetase↗
PubMed1977

Hereditary coproporphyria presenting with photosensitivity induced by the contraceptive pill.

A 26-year-old woman developed photosensitivity and jaundice after starting on an oral contraceptive agent. She was found to have hereditary coproporphyria. Histological examination of two liver biopsies taken during and after the acute attack did not reveal any changes thought to be due to hereditary coproporphyria. Screening of the patient's family revealed a further six latent cases.

Adult↗
PubMed1977

Pregnancy and the acute porphyrias.

An analysis is presented of the obstetric histories of 50 women with acute porphyria, comprising 39 with acute intermittent porphyria, 3 with variegate porphyria and 8 with hereditary coporporphyria. Fifty-four per cent of the women with acute intermittent porphyria had an acute attack of porphyria in pregnancy and/or the puerperium. Only one maternal death was recorded. One patient with variegate prophyria and two with hereditary coproporphyria had an attack related to pregnancy. The total fetal wastage was 13 per cent. The babies born to mothers with acute intermittent porphyria, who experienced an acute attack during pregnancy, were smaller than those in which no such attack occurred (P less than 0.001). In 13 non-porphyric primigravidae there was a rise in urinary excretion of delta-aminolaevulinic acid, porphobilinogen and coproporphyrin up to the 28th week of gestation. It is probable that pregnancy has some deleterious effects in acute prophyria but the prognosis of the porphyric pregnancy is much better than the literature suggests.

Acute Disease↗
PubMed1977

Hereditary coproporphyria and epilepsy.

A 9-year-old boy with mental deterioration and epilepsy suffered an acute attack of hereditary coproporphyria associated with worsening of seizure control. Leucocyte coproporphyrinogen oxidase activity was undetectable in the patient during this attack, and was reduced in his mother, a latent case. The complex relationship between porphyria, epilepsy, and anticonvulsant drugs is discussed.

Aminolevulinic Acid↗
PubMed1977

Hereditary coproporphyria. Demonstration of the abnormalities in haem biosynthesis in peripheral blood.

Hereditary coproporphyria is biochemically distinct from the other porphyrias and is characterized by excessive excretion of coproporphyrin in faeces and usually in urine. The laboratory findings in 28 patients with this disease are presented and the clinical details of eight patients who have been in attack summarised. The remaining 20 patients were latent for the disease. In all patients studied the activity of delta-aminolaevulinic acid synthase was raised and coproporphyrinogen oxidase depressed in the leucocyte. This indicates the partial enzyme block in the haem biosynthetic pathway in this disease. The activities of the other enzymes in the pathway, leucocyte ferrochelatase and erythrocyte delta-aminolaevulinic acid dehydratase, porphobilinogen deaminase and uroporphyrinogen decarboxylase showed no consistent change. On review of 111 cases, 35 per cent presented in acute attack: 80 per cent had abdominal pain, 34 per cent vomiting, 29 per cent solar sensitivity, 23 per cent neurological involvement, 23 per cent psychiatric symptoms and 20 per cent severe constipation. Only two fatalities have been published, both from respiratory failure. There was a female preponderance of cases in attack of 2-5:1 and in the latent cases of 1-5:1 suggesting hormonal provocation in the uncovering of the disease. Drugs were implicated as precipitating 54 per cent of acute attacks and in 34 per cent of cases, these were barbiturates. This study demonstrates the reduction in activity of coproporphyrinogen oxidase in the haem biosynthetic pathway and the elevation of delta-aminolaevulinic acid synthase in the peripheral blood. These features, together with the typical abnormal porphyrin excretion pattern, appear to be diagnostic of hereditary coproporphyria whether in attack, remission, or in the latent form.

5-Aminolevulinate Synthetase↗
PubMed1976

The porphyrinogenic effects of kryptopyrrole in the rat and the occurrence of urinary kryptopyrrole in human hereditary hepatic porphyria.

1. Kryptopyrrole (2,4-dimethyl-3-ethyl pyrrole) was shown to elevate the urinary porphyrin excretion and the hepatic content of porphyrins in the rat. The simultaneous administration of sigma-aminolaevulinic acid increased these effects. 2. Kryptopyrrole was present in the urine of patients with hereditary hepatic porphyria, in attack and in remission, but not in those with latent porphyria.

Aminolevulinic Acid↗
PubMed1976

Alcohol and absorption from the small intestine. 1. Impairment of absorption from the small intestine in alcoholics.

An absorption screen was performed in 10 chronic alcoholic patients within a few days of admission due to an acute alcoholic episode. Impaired absorption of d-Xylose was noted in three patients and low leucocyte ascorbic acid and serum folate levels in five. No abnormality was detected in jejunal histology. The absorption of water and electrolytes from the jejunum was studied in these patients using a triple-lumen tube perfusion system. The mean rate of absorption of water in the alcoholic subjects (50-0 +/- 2-3 ml/h) was significantly lower (P less than 0-001) than the mean value in 14 healthy control subjects (205 +/- 15-9 ml/h). A significant reduction of Na+ and Cl-absorption was also demonstrated in the alcoholic subjects. These results indicate that patients with acute-on-chronic alcoholism may have a function impairment of water and electrolyte absorption from the jejunum. This may, in part, account for some of the nutritional deficiencies in such patients and for symptoms such as diarrhoea which may be present.

Adult↗
PubMed1976

Alcohol and absorption from the small intestine. 2. Effect of ethanol on ATP and ATPase activities in guinea-pig jejunum.

After the exposure of isolated segments of guinea-pig jejunum to 2% ethanol for one hour, a significant reduction (P less than 0-001) in the adenosine triphosphate content (ATP) was observed when compared with levels found in segments perfused with Krebs' solution. However, no alteration was noted in the activity of adenosine triphosphatase (ATPase). The chronic administration of 50% ethanol in a dose of 2-5 g/kg for two weeks did not affect either the ATP content or ATPase activity in jejunal mucosa.

Adenosine Triphosphatases↗