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Biomedical subjects

A Goldberg

Publications and source records attributed to A Goldberg.

At least 217 records · Page 12Linked to original sources
PubMed1978

Delta-aminolaevulinic acid metabolism in normal and lead-exposed humans.

The activity of the haem biosynthetic enzymes delta-aminolaevulinic acid synthetase (ALA.S) and delta-aminolaevulinic acid dehydratase (ALA.D) were measured in the peripheral blood of a group of lead workers and control subjects. The haem precursor delta-aminolaevulinic acid (ALA) was measured in blood and urine, whilst lead levels were measured in whole blood. The inter-relationships between all these parameters were examined and quantified. The results demonstrate that above a blood lead concentration of 2 mumole/l and below an erythrocyte ALA.D activity of 18 nmole ALA utlized/min/ml red blood cells (R.B.C.), Haem synthesis is depressed to such an extent that the activity of leucocyte ALA.S, the rate-limiting enzyme of haem biosynthesis, is increased by negative feedback.

5-Aminolevulinate Synthetase↗
PubMed1978

Thyroid function in acute intermittent porphyria: a neurogenic cause of hyperthyroidism?

Thyroid function was investigated in 17 patients with acute intermittent porphyria (AIP). In 13 patients in remission and latent for the disease, thyroid function was normal. In contrast, transient hyperthyoridism with elevated total T4, T3 free T4 and T3, and FTI levels occurred in one pregnant patient with severe attacks of AIP, and similar, though less pronounced, alterations in thyroid function were found in three other symptomatic female patients. It is suggested that increased thyroidal sympathetic neural stimulation is responsible for these changes in thyroid function.

Adult↗
PubMed1978

Erythrocyte delta-aminolaevulinic acid dehydratase activity and changes in delta-aminolaevulinic acid concentration in various forms of anaemia.

Whole blood delta-aminolaevulinic acid (ALA) concentrations and erythrocyte ALA dehydratase activity have been measured in patients with iron deficiency anaemia, megaloblastic anaemia and secondary anaemia, and in normal subjects. ALA concentration was found to be significantly increased in all types of anaemia compared with normal. Erythrocyte ALA dehydratase activity was significantly increased in iron deficiency and megaloblastic anaemia but not in secondary anaemia.

Aminolevulinic Acid↗
PubMed1978

Haem biosynthesis in rheumatoid disease.

The activities in blood of six enzymes of the haem biosynthetic pathway have been determined in 12 patients with rheumatoid disease, six of whom were anaemic. The porphyrin and porphyrin-precursor intermediary products of haem biosynthesis were also determined in blood, urine and faeces. No significant differences were found between anaemic and non-anaemic subjects. Failure of delta-amino-laevulinate synthase activity to increase in response to anaemia may be the nature of the marrow unresponsiveness suggested as one factor in the causation of the anaemia. Normal ferrochelatase activity and normal concentrations of free protoporphyrin support the view that iron is effectively unavailable although present in normal amounts. Coproporphyrinogen oxidase activity was significantly depressed.

5-Aminolevulinate Synthetase↗
PubMed1978

Hepatic drug metabolism and haem biosynthesis in lead-poisoned rats.

1 Pretreatment of rats with intraperitoneal injections of lead was shown to result in a depression of the microsomal mixed function oxidase system, as assessed by a decrease in hepatic microsomal P-450 and b5 content and by a decrease in the activity of the enzymes aniline hydroxylase and aminopyrine demethylase. Lead had a more marked effect on cytochrome P-450 than b5. 2 The activity of the rate-limiting enzyme of haem biosynthesis, delta-aminolaevulinic acid synthase, was inversely correlated with the microsomal cytochrome P-450 content. 3 The activity of the haem biosynthetic enzymes delta-aminolaevulinic acid dehydratase, coproporphyrinogen oxidase and ferrochelatase were decreased by increasing lead pretreatment. 4 The activity of the haem catabolic enzyme, haem oxygenase, was increased by lead pretreatment.

5-Aminolevulinate Synthetase↗
PubMed1978

Computer-assisted review of digoxin therapy in the elderly.

Current practice with digoxin was assessed in a group of 42 elderly patients by comparing plasma digoxin concentrations attained on previously established maintenance doses with those generated by a computer programme designed to calculate dosage schedules to suit individual patients. Discrepancies between measured and computed plasma levels and between established and computed doses dictated withdrawal of the drug or revision of dosage in 26 patients (62%), with obvious clinical benefit. An important determinant of dosage was renal function; reduction in creatinine clearance provided good evidence for the loss of ability of the elderly kidney to eliminate digoxin. Simple bedside methods are available which permit a reliable estimate of creatinine clearance without a 24-hour urine collection, provoding a rational basis for the choice of digoxin dosage in the elderly.

Aged↗
PubMed1978

A study of thyroid function in psychiatric in-patients.

The prevalence of abnormal serum total thyroxine (T4) and triiodothyronine (T3) concentrations were determined in 1,206 in-patients in two associated psychiatric hospitals. The biochemical pattern of primary hypothyroidism occurred in five females and one male (prevalence 0.5 per cent), but in only one patient was the diagnosis clinically obvious. Eight patients (all female) were clinically hyperthyroid (prevalence 0.7 per cent), of whom six were previously undiagnosed. There was no evidence that phenothiazines or benzodiazepine therapy had any significant effect on thyroid hormone levels. The small differences in thyroid hormone levels between psychiatric diagnostic groups could be explained by differences in age distribution.

Adolescent↗
PubMed1978

Adipose tissue lipoprotein lipase in chronic hemodialysis: role in plasma triglyceride metabolism.

The role of adipose tissue lipoprotein lipase (LPL) in the pathogenesis of hypertriglyceridemia in uremic patients receiving maintenance hemodialysis was evaluated. The fasting level of adipose tissue LPL activity was reduced below normal (3.4 +/- 2.5 microU/106 cells; n = 23; mean +/- SD) in hypertriglyceridemic dialysis patients (1.5 +/- 0.8; P less than 0.01; n = 15) and did not differ from normal in normotriglyceridemic dialysis patients (2.5 +/- 2.4; P = NS; n = 13). The enzyme activity increased as a function of relative body weight in normotriglyceridemic hemodialysis patients (r = 0.21; P less than 0.05) but not in the hypertriglyceridemic group (r = 0.21; P = NS). There was an abnormal response of LPL to feeding in the hypertriglyceridemic dialysis patients. The postprandial level of LPL was significantly lower in hypertriglyceridemic dialysis patients (2.2 +/- 1.0; n = 9) than in normotriglyceridemic dialysis patients (3.9 +/- 1.9; P less than 0.05; n = 10) or normal controls (4.8 +/- 1.8; P less than 0.01; n = 12). Whereas the postprandial change in LPL was inversely related to the fasting enzyme activity in normotriglyceridemic dialysis patients (r = 0.74; P less than 0.02; n = 10) and in normal controls (r = 0.58; P less than 0.05; n = 12), no such relationship existed in hypertriglyceridemic dialysis patients (r = 0.17; P = NS; n = 9). Furthermore, fasting plasma triglyceride levels in the entire group of dialysis patients were a function of the postprandial level of LPL activity (rs = 0.574; P less than 0.02; n = 19). Since the level of LPL 1) is below normal in both the fasted and fed state in the hypertriglyceridemic hemodialysis patients, 2) is normal in both the fasted and fed state in the normotriglyceridemic hemodialysis patients, and 3) in the fed state is inversely correlated with the fasting plasma triglyceride concentration in the entire group of hemodialysis patients, it is proposed that adipose tissue LPL plays a role in the etiology of hypertriglyceridemia in hemodialysis patients.

Adipose Tissue↗
PubMed1977

The effects of industrial lead poisoning on cytochrome P450 mediated phenazone (antipyrine) hydroxylation.

In a group of ten male adults admitted to hospital with clinical symptoms of lead exposure, phenazone, elimination rates, blood delta-amino-laevulinic acid dehydratase (ALA.D) activity, blood lead levels and haemoglobin were measured. Investigations were carried out before, immediately after and again at least 12 weeks after cessation of CaEDTA (sodium calcium edetate) chelation therapy. Following chelation, phenazone elimination rates were increased as assessed by a decrease in half life and increase in clearance. This was significant, both immediately after and 12 weeks after cessation of chelation therapy. The change in rate of phenazone metabolism was associated with improved clinical status, with lowered blood lead levels and raised haemoglobin and ALA.D activity. The results of the study suggest that the depression in phenazone elimination in lead intoxication is possibly due to depressed hepatic cytochrome P450 levels.

Adult↗
PubMed1977

Enzyme abnormalities in the porphyrias.

Evidence is presented that each of the porphyrias represents a different inborn error of metabolism in haem biosynthesis. Control of the pathway takes place by feedback repression and inhibition by haem of delta-aminolaevulinic-acid synthase. It is suggested that insituations where the activity of this enzyme is derepressed, prophobilinogen deaminase represents a secondary control step.

5-Aminolevulinate Synthetase↗
PubMed1977

The effect of calcium on lead absorption in rats.

The effects of Ca2+ on lead absorption as PbCl2 and 203PbCl2 were studied in rats. 1. Doubling of dietary calcium with Ca3(PO4)2 significantly decreased lead absorption as assessed by 203Pb retention, tissue lead concentration, urinary excretion of delta-aminolaevulinate and increased activities of delta-aminolaevulinate dehydratase and ferrochelatase. 2. Similar effects on lead absorption were shown by the Ca2+ salts, Cl-, CO32-, PO43-, SO42-, gluconate and glycerophosphate. 3. CaCl2 and calcium glycerophosphate were found to be most effective in decreasing lead absorption when administered immediately before lead dosage. 4. A negative exponential relationship was found between CaCl2 concentration and 203Pb absorption at 120h. The result suggest that, above 4 mmol of administered calcium, residual lead absorption is unaffected by increasing gastrointestinal calcium concentrations. 5. Increased systemic calcium had no effect on lead retention. 6. Calcium in the concentrations found in domestic hard-water supplies significantly decreased absorption of a solution of 203Pb dissolved in it compared with absorption of 203Pb dissolved in soft or distilled water. 7. Milk and skimmed milk were found to have no effect on 203Pb absorption in rats.

Animals↗
PubMed1977

A retrospective analysis of blood-lead in mentally retarded children.

Blood-lead concentrations were measured retrospectively in the blood contained on cards used for testing for phenylketonuria in the first two weeks of life. Cards which belonged to 80 of a group of 77 children with mental retardation of unknown aetiology and 77 controls were identified. Of 77 usable cards, 41 were from mentally retarded children and 36 were from controls; 24 mental-retardation/control pairs were found. There was a highly significant trend towards higher blood-lead concentrations in the mentally retarded children. Water-lead concentrations in the maternal home during pregnancy correlated with blood-lead concentrations in the mentally retarded children. These results reinforce the probable association between lead exposure during pregnancy and the development of mental retardation of otherwise unknown aetiology.

Child↗
PubMed1977

Renal insufficiency associated with excessive lead exposure.

Water lead concentrations were measured in 970 households throughout Scotland. Blood lead concentrations were measured in 283 people living in houses with water lead levels of over 0-48 mumol/l (100 mug/l). A highly significant correlation was found between lead concentrations in water and blood. Raised blood lead concentrations were associated with renal insufficiency, reflected in raised serum urea concentrations, and with hyperuricaemia, although there was no evidence of clinical disease in any of the affected people. This is further evidence that excessive lead in domestic water supplies has a harmful effect on the community's health.

Environmental Exposure↗