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Biomedical subjects

R W Charlton

Publications and source records attributed to R W Charlton.

At least 19 recordsLinked to original sources
PubMed1979

Serum ferritin concentrations in black miners.

Serum ferritin concentrations were measured in 651 Black male miners who originated from rural areas throughout southern Africa and who were aged between 17 and 57 years. The mean serum ferritin concentration of 229 microgram/l was above the normal range reported for White subjects, and in 52,8% of the subjects the values were greater than 200 microgram/l. The serum ferritin concentration rose with age, as did the proportion of subjects in each age group who exhibited high values (more than 200 microgram/l). The lowest mean ferritin concentration (112 microgram/l) as well as the lowest proportion of high values (22,9%) were found in subjects from the most northerly area studied. Similarly, the highest mean proportion of high values (66,3%) was seen in the most southerly group studied. Calculations from the present data suggest that the degree of iron overload is currently greater in rural than in urban Black male subjects.

Adult↗
PubMed1979

Changing patterns of dietary iron overload in black South Africans.

Over the last 17 years there has been a significant reduction in the prevalence and severity of dietary iron overload in urban blacks of Johannesburg. This is attributed to a decrease in the consumption of traditionally brewed beer of high iron content over this period. A 40% reduction was found in hepatic iron concentrations measured in necropsy specimens from 248 male patients who died in 1976 as compared with 220 who died in 1959 and 1960. While hepatic iron concentrations rose with age in both groups there was no evidence of iron accumulation during the period between the two studies. Hepatic iron concentrations measured in 345 female subjects were many fold less than those of males and the 1976 group did not differ significantly from the 1959 to 1960 group. A paradoxical increase in the prevalence of portal fibrosis and cirrhosis was seen and may be due to the effects of increased ingestion of spirits and fortified wine in recent years. Iron overload was significantly greater in males with carcinoma of the esophagus and in those with idiopathic heart failure when compared to subjects who died of other causes. This suggests excessive exposure of these subjects to traditionally brewed beverages and the adulterants present in them.

Adult↗
PubMed1979

The relationship between marrow iron stores, plasma ferritin concentrations and iron absorption.

The percentage absorption from a 3 mg dose of ferrous iron was measured in 50 subjects with iron stores that varied over a wide range. Iron status was assessed by a number of measurements, including the haemoglobin concentration, the plasma iron concentration, the total iron-binding capacity, the plasma ferritin concentration and the concentration of non-haem iron in the bone marrow. There were good inverse correlations between the log percentage iron absorption and both the log marrow non-haem iron concentration (r -0.94; P less than 0.001) and the log plasma ferritin concentration (r -0.78; P less than 0.001). In addition, there was a positive ferritin concentration (r +0.84; P less than 0.001). These results suggest that reticuloendothelial iron stores represent an important determinant of iron absorption and that their size can be guaged from the plasma ferritin concentration.

Anemia↗
PubMed1978

The mechanism of endotoxin-induced hypoferraemia.

The effect of endotoxin on the processing of erythrocyte iron by reticuloendothelial cells of the liver and spleen was studied in rats using heat damaged erythrocytes labelled with 59Fe. Endotoxin did not alter the uptake of the damaged cells but markedly inhibited the subsequent early phase of iron release from the reticuloendothelial cells. The inhibition seemed to be due to both a decreased rate of labelled haem destruction and an increased incorporation of radioiron into ferritin. Although early iron release was decreased 0--2 h after endotoxin administration, the diversion of iron into ferritin was more marked when endotoxin was given 18 h before. The block in iron release was partially overcome in animals that had been kept on an iron free diet or had been phlebotomised. In these animals the decreased rate of haem catabolism remained unaltered but less iron was diverted into ferritin.

Anemia, Hypochromic↗
PubMed1978

Serum and tumour ferritins in primary liver cancer.

Serum ferritin concentrations were found to be raised, often considerably, in 58 of 76 black patients with primary liver cancer (PLC). No correlation could be demonstrated between the serum ferritin concentration and several other measurements, including the following: hepatic iron stores measured chemically, the size of the tumour, serum transaminase values, and the presence or absence of cirrhosis in the non-tumorous liver. There was, however, a negative correlation between serum ferritin and alpha-foetoprotein concentrations. Ferritin was purified from PLC tissue obtained from three patients at necropsy and the distribution of isoferritins was determined by isoelectric focusing. Acidic isoferritins similar to those previously found in PLC tissue were obtained. Their acidic nature was confirmed chromatographically using DEAE cellulose. Because the serum ferritin in patients with PLC probably consists of a mixture of normal and acidic isoferritins, it is likely that the serum assay used in the present study underestimated the actual concentrations present. With the development of an assay which utlises a specific antibody against acidic PLC isoferritins, serum ferritin may prove to be a second marker for PLC.

Adult↗
PubMed1977

Anaemia, iron deficiency and exercise: extended studies in human subjects.

1. Ventilation and cardiac frequency were measured during repeated treadmill exercise in three healthy subjects over 36 weeks, before, during and after iron-deficiency anaemia was produced and after iron treatment. The haemoglobin and 2,3-diphosphoglycerate concentrations and the oxygen-binding (P50) were measured. 2. There was an inverse relationship between the haemoglobin concentrations and the 2,3-diphosphoglycerate concentrations and the P50 values. 3. The mean cardiac frequencies during the fourth to tenth minutes of exercise showed a negative correlation with the haemoglobin concentrations in all three subjects, and the mean minute ventilations in two of them.

Adult↗
PubMed1976

Patterns of food iron absorption in iron-deficient white and indian subjects and in venesected haemochromatotic patients.

The absorption of radioactive iron from a solution of ferrous ascorbate, and from a standard meal containing intrinsically labelled haemoglobin and wheat, was measured in 12 Indian housewives, 18 white hospital patients and 12 subjects with idiopathic haemochromatosis. Eight of the latter had been fully treated by multiple venesections, so that their serum ferritin concentrations were below 25 mug/1. Since the serum ferritin concentrations of the housewives and the hospital patients were comparable, their body iron stores were considered to be depleted to a similar degree. There were no significant differences between the absorptions of ferrous ascorbate or of the haem iron in the standard meal by each group, but the housewives and the hospital patients absorbed significantly less of the non-haem food iron. The mean non-haem food iron absorptions were 36.4%, 5.8% and 18.9% for the treated haemochromatotic subjects, the Indian housewives and the white hospital patients respectively. The discrepancies between the absorptions of the different forms of food iron were highlighted by calculating the ratios between them. The mean non-haem: haem food iron absorption ratio for the group of treated haemochromatotic subjects was 0.98, and for the Indian housewives only 0.18. The white hospital patients did not form a homogenous population: the ratios of the five males and three of the females were greater than 1.0, whereas those of the remaining 10 females were less than 0.5. The results of this study suggest that mal-absorption of non-haem iron from a meal containing bread, presumably due to a defect at the luminal level, may be an important factor in the pathogenesis of iron deficiency in some subjects. The abnormality appears to be particularly prevalent among Indian women living in Durban.

Adolescent↗
PubMed1975

Studies on the fortification of cane sugar with iron and ascorbic acid.

1. The feasibility of improving iron nutrition by fortifying cane sugar with Fe and ascorbic acid was studied. 2. It was found to be possible to add a number of Fe salts together with ascorbic acid to sugar without affecting its appearance or storage properties. 3. The absorption of Fe from fortified sugar eaten with maize-meal porridge or made into jam or biscuits was measured in ninety-four volunteer multiparous Indian women using the 59-Fe erythrocyte utlization method. 4. The absorption of Fe from sugar fortified with ascorbic acid and ferrous sulphate and eaten with maize-meal porridge was increased about twofold in the ratio, ascorbic acid:Fe was 10:1 by weight. If the ratio was increased to 20:2, Fe absorption was increased a further threefold. 5. Sugar fortified with soluble Fe salts, including FeSO4.7H2O, discoloured both tea and coffee; sugar fortified with ferric orthophosphate did not have this effect. 6. Fe from FePO4.H2O was poorly absorbed when added with sugar to maize-meal porridge, and also when added with adequate quantities of ascorbic acid. This form of Fe was absorbed much less well than was the intrinsic Fe present in the maize. 7. When sugar fortified with FePO4.H2O and ascorbic acid was added to maize-meal porridge before cooling or was made into jam there was a several-fold increase in the amount of Fe absorbed.

Adult↗
PubMed1975

The effect of tea on iron absorption.

The effect of tea on iron absorption was studied in human volunteers. Absorption from solutions of FeCl3 and FeSO4, bread, a meal of rice with potato and onion soup, and uncooked haemoglobin was inhibited whether ascorbic acid was present or not. No inhibition was noted if the haemoglobin was cooked. The effect on the absorption of non-haem iron was ascribed to the formation of insoluble iron tannate complexes. Drinking tannin-containing beverages such as tea with meals may contribute to the pathogenesis of iron deficiency if the diet consists largely of vegetable foodstuffs.

Adult↗