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Biomedical subjects

R D Baynes

Publications and source records attributed to R D Baynes.

At least 73 records · Page 4Linked to original sources
PubMed1988

Neutrophil lactoferrin content in viral infections.

In an attempt to elucidate the previously observed decrease in plasma lactoferrin-neutrophil ratio in subjects with acute viral infections, a study of the neutrophil lactoferrin content in such infections was undertaken. With the use of an immunoperoxidase stain for lactoferrin, neutrophils in viral illness were shown to have reduced lactoferrin content (mean score 97.9 +/- SD [38.0] per 100 neutrophils) as compared with normal subjects (mean score 196.4 +/- SD [3.6] per 100 neutrophils) (t = 7.69; P less than 0.0005). This suggests an acquired defect of neutrophil lactoferrin synthesis in viral infection. This finding is of importance when seen against the well-recognized increased risk of bacterial superinfection in subjects who have recently had a viral infection.

Adult↗
PubMed1988

Effect of lupines, a protein-rich legume, on iron absorption.

The absorption of iron from lupines, a protein-rich legume, was assessed in 35 parous Indian women. Iron bioavailability was shown to be as low for lupines as soybeans (geometric mean absorptions 0.9 and 1.7 per cent respectively, P less than 0.005). The addition of 30 mg of ascorbic acid moderately improved the geometric mean iron absorption from 1.0 to 5.3 per cent (P less than 0.0001), and 60 mg ascorbic acid from 0.7 to 6.9 per cent (P less than 0.0001). The phytate and polyphenol content of lupines was negligible. The demonstration of poor iron bioavailability from a legume of otherwise rich nutritional potential has important implications in nutritional planning programmes for developing countries.

Dietary Proteins↗
PubMed1987

Idiopathic haemochromatosis. Family studies and results of a pilot prevalence survey.

HLA typing for the A and B loci was carried out in conjunction with measurements of iron status on 38 of the first-degree relatives of 8 patients suffering from idiopathic haemochromatosis (IHC). Seven of the 8 probands had the A3 allele, 2 in the homozygous form. Seven had the B7 allele and in 5 it was present with the A3 allele on the same chromosome. Six family members were diagnosed as homozygous for the HLA-linked iron-loading gene on the basis of genotype assessment, while 27 were assessed as being heterozygous. Five of the 6 homozygous subjects had developed significant iron overload. In contrast, disturbances of iron metabolism in the heterozygotes were mild and present in only 33%. Pseudodominant inheritance of IHC was noted in one family, presumably as the result of a homozygous/heterozygous mating. A pilot epidemiological survey was carried out on 222 Afrikaans-speaking men in an attempt to find affected individuals using the serum ferritin concentration as the screening test. One homozygous subject was identified (genotype A3, B7/A3, B7) and further family studies confirmed the presence of the HLA-linked iron-loading gene. These preliminary results suggest a disease frequency of about 4-5/1,000 in the Afrikaner population.

Adolescent↗
PubMed1987

Apotransferrin receptors and the delivery of iron from cultured human blood monocytes.

A study was done to find out whether apotransferrin receptors are involved in the release of iron from reticuloendothelial cells. To this end, human macrophages which had been obtained by culturing blood monocytes for 7 days were incubated with either diferric or apotransferrin at the physiological pH of 7.4 or at an acidic pH (6.0). While specific diferric transferrin receptors (Kd 1.3 X 10(-8) M) were demonstrated at pH 7.4, no apotransferrin receptors were found. In contrast, both diferric receptors (Kd 2.1 X 10(-8) M) and apotransferrin receptors (Kd 6.8 X 10(-9) M) were found at pH 6.0. The findings of specific apotransferrin binding at acidic pH fits in with the current understanding of iron uptake by cells, in which the iron-transferrin complex is endocytosed and the iron is released at acidic pH. The present results suggest that the apotransferrin remains attached to its receptor in the endocytosed vesicle at this acidic pH but that it becomes detached at the cell surface where the pH is neutral. No evidence was found to indicate that iron is transported out of macrophages via apotransferrin receptors at the physiological pH.

Apoproteins↗
PubMed1987

The effects of fruit juices and fruits on the absorption of iron from a rice meal.

The effects of the chemical composition of fruit juices and fruit on the absorption of iron from a rice (Oryza sativa) meal were measured in 234 parous Indian women, using the erythrocyte utilization of radioactive Fe method. The corrected geometric mean Fe absorptions with different juices varied between 0.040 and 0.129, with the variation correlating closely with the ascorbic acid contents of the juices (rs 0.838, P less than 0.01). Ascorbic acid was not the only organic acid responsible for the promoting effects of citrus fruit juices on Fe absorption. Fe absorption from laboratory 'orange juice' (100 ml water, 33 mg ascorbic acid and 750 mg citric acid) was significantly better than that from 100 ml water and 33 mg ascorbic acid alone (0.097 and 0.059 respectively), while Fe absorption from 100 ml orange juice (28 mg ascorbic acid) was better than that from 100 ml water containing the same amount of ascorbic acid (0.139 and 0.098 respectively). Finally, Fe absorption from laboratory 'lemon juice' (100 ml orange juice and 4 g citric acid) was significantly better than that from 100 ml orange juice (0.226 and 0.166 respectively). The corrected geometric mean Fe absorption from the rice meal was 0.025. Several fruits had little or no effect on Fe absorption from the meal (0.013-0.024). These included grape (Vitis vinifera), peach (Prunus persica), apple (Malus sylvestris) and avocado pear (Persea americana). Fruit with a mild to moderate enhancing effect on Fe absorption (0.031-0.088) included strawberry (Fragaria sp.) (uncorrected values), plum (Prunus domestica), rhubarb (Rheum rhaponticum), banana (Musa cavendishii), mango (Mangifera indica), pear (Pyrus communis), cantaloup (Cucumis melo) and pineapple (Ananas comosus) (uncorrected values). Guava (Psidium guajava) and pawpaw (Carica papaya) markedly increased Fe absorption (0.126-0.293). There was a close correlation between Fe absorption and the ascorbic acid content of the fruits tested (rs 0.738, P less than 0.0001). There was also a weaker but significant correlation with the citric acid content (rs 0.55, P less than 0.03). Although this may have reflected a direct effect of citric acid on Fe absorption, it should be noted that fruits containing citric acid also contained ascorbic acid (rs 0.70, P less than 0.002).(ABSTRACT TRUNCATED AT 400 WORDS)

Absorption↗
PubMed1987

Factors influencing the absorption of iron from soya-bean protein products.

The absorption of iron from soya-bean (Glycine hispida)-based and milk-based infant formulas was assessed in 138 multiparous Indian women, using the erythrocyte utilization of radioactive Fe method. Fe absorption was significantly greater from the basal milk formula (1.5 g protein) than it was from the basal soya-bean formula (2.3 g protein), with geometric mean values of 0.083 and 0.044 respectively. Ascorbic acid markedly increased Fe absorption from the milk-based formula in a dose-dependent fashion. The increase was fivefold when the ascorbic acid:Fe ratio on a weight-for-weight basis was 6:1 and over tenfold when it was 20:1. In contrast, ascorbic acid had a less-marked effect on the absorption of Fe from the soya-bean-based formula, with only a two- to threefold increase at an ascorbic acid:Fe ratio of 20:1. The geometric mean Fe absorption from the soya-bean formula (1.27 mg Fe, 2.3 g isolated soya-bean protein (ISP] was somewhat less than that from the same amounts of ISP and ascorbic acid made up in milk (0.075 and 0.113 respectively). However, a direct comparison between the soya-bean formula in milk and in water showed no significant difference (0.043 and 0.060 respectively). Fe absorption from a drink containing 10 g ISP and 30 mg ascorbic acid was significantly better than that from a similar drink containing the soya-bean flour from which ISP is extracted (0.044 and 0.027 respectively). Heating ISP to 200 degrees for 2 h before its use had no effect on Fe availability.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorption↗
PubMed1987

Curry powder as a vehicle for iron fortification: effects on iron absorption.

Curry powder was investigated as a vehicle for targeted iron (Fe) fortification, and especially for NaFeEDTA, by assessing its acceptability to consumers and its effects on Fe absorption. A random survey in an Indian community in the Republic of South Africa, indicated that fortified premixed curry powder was acceptable in terms of color, palatability, and stability. The effect of curry powder on Fe absorption from a potato meal was assessed in 64 Indian housewives. Curry powder caused a significant though modest rise in Fe absorption in two of the studies (t = 2.716, p less than 0.05 and t = 3.126, p less than 0.025) but, in the third, the effect was noted only in the more Fe-depleted subjects. There was no enhancement of Fe absorption from a dhal soup of low-Fe bioavailability (t = 0.224, p greater than 0.1). The results of both the human and animal studies suggested that curry powder's overall mild enhancing effect on Fe absorption was due to its capacity to stimulate gastric acid secretion.

Anemia, Hypochromic↗
PubMed1987

Hematologic and iron-related measurements in rheumatoid arthritis.

The hematologic status of 265 patients with rheumatoid arthritis was assessed. In the group as a whole, a mild depression in the hemoglobin concentration and mean cell volume (MCV) was associated with an increase in the red blood cell distribution width (RDW), erythrocyte sedimentation rate (ESR), and platelet count. Bone marrow trephine biopsies and further measurements of iron status and disease activity were done in [a further] 38 more anemic patients, and the findings in those with absent marrow iron (iron deficiency) were compared with those having stainable stores (anemia of chronic disorders). The RDW was raised in both, and there was no significant difference between the two groups. The concentrations of nonheme iron in the marrow and of serum ferritin were significantly lower in the iron-deficient group, but the geometric mean serum ferritin of 34 micrograms/L was still a good deal higher than that associated with uncomplicated iron deficiency. This was presumably because of the fact that the serum ferritin, which was significantly correlated with the ESR (r 0.55; P less than 0.0004) and C-reactive protein (CRP) r 0.41; P less than 0.01), was also functioning as an acute phase protein. While there was a weak correlation (r 0.37; P less than 0.04) between the marrow nonheme iron and the serum ferritin concentrations, it disappeared when nonactive patients with normal CRP concentrations were excluded. The absence of a correlation is unlike the findings that have previously been noted in other chronic inflammatory conditions and in neoplasia. This raises the possibility that serum ferritin concentrations in rheumatoid arthritis may reflect, in part at least, another store of iron located in affected joints.

Anemia↗
PubMed1987

Reactive thrombocytosis in pulmonary tuberculosis.

The incidence of reactive thrombocytosis in active pulmonary tuberculosis was studied in 122 patients. Thrombocytosis was common, platelet counts often exceeding 1 X 10(12)/1. A significant inverse correlation was noted between the mean platelet volume and the platelet count (r = -0.54, p less than 0.0001). Interval estimation suggested that this relation was non-linear. Further studies were done in a small group of six patients. Platelet survival was considerably shortened, the platelets aggregated excessively in vitro, serum concentrations of thrombopoiesis stimulating activity were raised, and serotonin uptake and release were within normal limits. The degree of thrombocytosis correlated significantly with the degree of inflammation measured by the erythrocyte sedimentation rate (r = 0.40, p less than 0.003) and serum C-reactive protein concentration (r = 0.35, p less than 0.008).

Arachidonic Acids↗
PubMed1987

The HLA linked iron loading gene in an Afrikaner population.

The serum ferritin concentration was used as a screening test to identify the presence of iron overload in 599 Afrikaans subjects (300 males and 299 females) living in the South Western Cape, South Africa. Seventeen of the males with concentrations greater than 400 micrograms/l were reevaluated three and five years later. Serum ferritin concentrations were measured again and further diagnostic procedures were carried out. These included an assessment of alcohol intake and measurements of serum gamma glutamyltransferase, the percentage saturation of transferrin, and HLA-A,-B,-C, and -DR loci typing on the subjects as well as their families. Liver biopsies were performed on some affected subjects. Of the original 16 index subjects, four were diagnosed as homozygous for the HLA linked iron loading gene which is responsible for the clinical disease idiopathic haemochromatosis. Six appeared to be heterozygotes, three were heterozygotes who were also abusing alcohol, and two did not fit into any of the diagnostic groups. The calculated gene frequency was 0.082, with an expected heterozygote frequency of 0.148. The fact that no females were identified in the study suggested that the diagnostic criteria for homozygosity (serum ferritin greater than 400 micrograms/l and % saturation greater than 60%) were set too high. The data were therefore recalculated for the 300 males; when this was done the gene frequency was 0.115 and the heterozygote frequency 0.024. Two subjects were diagnosed as homozygotes in the study of family members and 37 as heterozygotes (33 definite and four probable). Both the homozygotes and nine of the heterozygotes showed mild to moderate disturbances of iron metabolism. There was considerable overlap between the phenotype expression in these nine heterozygotes and the homozygotes, probably as a result of setting the threshold for the serum ferritin concentrations at the relatively high value of 400 microgram/ml. By doing this a small subset of heterozygotes with biochemical abnormalities was identified. The results of the present pilot study suggest a high frequency of the HLA linked iron loading gene in the Afrikaner population of South Western Cape.

Adolescent↗
PubMed1987

Hematologic, iron-related, and acute-phase protein responses to sustained strenuous exercise.

This study was undertaken to gain insight into the mechanisms responsible for the hypoferremia occurring after severe exercise. To this end, 18 athletes who were competing in a 160-km triathlon involving canoeing, cycling, and running were evaluated before the race, immediately after the finish, and thereafter at 30 min, 24 h, and 48 h. The evaluation included plasma iron, total iron-binding capacity, lactoferrin, ferritin, haptoglobin, cortisol, various enzymes, and white cell count. The cortisol, white cell count, and lactoferrin were significantly increased immediately after the race, while the plasma iron and transferrin saturation were significantly decreased. There was a 40% but nonsignificant rise in the plasma ferritin at the completion of the race, while the C-reactive protein was raised by nearly 300% at 24 h. In contrast, haptoglobin declined significantly by 24 h but was normal again 24 h later. Quantitative considerations suggested that the lactoferrin was not responsible for removing transferrin iron from circulation and hence causing the hypoferremia. Instead, it seemed more likely that the iron-related changes were occurring as part of an acute phase response initiated by muscle injury.

Acute-Phase Proteins↗
PubMed1987

Relationship between absorption of inorganic and food iron in field studies.

Food iron absorption data on 853 Indian women were compared to the haemoglobin concentrations, other iron-related measurements and the absorption of a reference dose of 3 mg iron given as ferrous ascorbate. The serum ferritin concentration was identified as the best predictor of the absorption of the reference dose (r = -0.54, p less than 0.0001). These two measurements were then compared in terms of their relative ability to predict the absorption of iron from 10 individual meals. Results were comparable, with correlations for the pooled data of -0.50 (p less than 0.0001) for the serum ferritin and 0.47 (p less than 0.0001) for the reference dose. Since serum ferritin is a simple and non-invasive test, it may represent the more satisfactory way of standardising food iron absorption results to a common iron status in field studies. However, the value of such an approach is limited by the wide confidence limits of the relationship between food iron absorption and both the other measurements.

Absorption↗
PubMed1986

Blastomycosis. A case report.

Blastomycosis was once thought to be restricted to North America; it has rarely been found in the RSA. The first case reported in the RSA was associated with a diffuse pulmonary infiltrate and cavitation; the patient responded to amphotericin B.

Amphotericin B↗
PubMed1986

Iron and folate status of pregnant black women in Gazankulu.

A limited nutritional survey was carried out in 229 first attenders at an antenatal clinic in Gazankulu during the winter of 1984. Haemoglobin concentrations equal to or less than 11 g/dl were found in 33% of these women, the prime reason being folate deficiency. Serum folate concentrations were less than a 3.5 ng/ml in 60% of subjects and less than 3.0 ng/ml in 48%. A mean corpuscular volume of 100 fl or more, which reflects a defect in red cell DNA synthesis, was present in 35%. Iron related measurements indicated that only 17% were also iron deficient but the figure is certainly an underestimate, since the presence of folate deficiency tends to mask concomitant iron deficiency. The findings underline the need for folate and iron supplementation in pregnancy; the very high prevalence of significant folate deficiency also indicates that serious consideration should be given to the fortification of maize meal with folic acid.

Black or African American↗
PubMed1986

Red blood cell distribution width in the anemia secondary to tuberculosis.

A study was done to explore the claim that anisocytosis as measured by the red blood cell volume distribution width (RDW) is raised in iron-deficiency anemia, but is normal in the anemia of chronic disorders. Measurements were done on 283 normal patients, 22 iron-deficient patients, and 102 tuberculotic patients, using a model S plus Coulter Electronic Counter with standard calibration. Mean (+/- SD) values for RDW were as follows: normals, 7.36 (+/- 0.57); untreated iron deficiency, 10.39 (+/- 1.37); and 15 untreated anemic patients with tuberculosis, 10.44 (+/- 0.63). Mean values remained above 10.4 in 69 patients with tuberculosis during treatment, irrespective of whether or not the patients were anemic, but had fallen towards the normal mean (8.49 +/- 0.8) in the 18 subjects in whom it was measured at the end of therapy. By this time the mean corpuscular volume (MCV) and hemoglobin concentrations had risen to normal. It is concluded that RDW values in the chronic inflammatory disorder tuberculosis are not significantly different from those occurring in iron-deficiency anemia.

Anemia↗
PubMed1986

Failure of transferrin to enhance iron absorption in achlorhydric human subjects.

There is evidence in experimental animals that transferrin, produced either by gastrointestinal cells or derived from bile, mediates the luminal absorption of iron. The applicability of these findings to human subjects was tested by administering diferric transferrin labelled with 3 mg 59Fe to seven patients with pernicious anaemia. Achlorhydric subjects were chosen to ensure that the iron transferrin complex did not dissociate in the stomach. The geometric mean absorption of 1.4% was similar to that of 3 mg iron given as ferric chloride (1.9%) and much less than that of ferrous ascorbate (18.9%). These findings suggest that transferrin does not play a physiological role in the absorption of iron in human subjects.

Achlorhydria↗