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Biomedical subjects

J Fielding

Publications and source records attributed to J Fielding.

At least 37 records · Page 2Linked to original sources
PubMed1985

Size of spleen rather than amount of platelet sequestration may determine long term responses to splenectomy in adult idiopathic thrombocytopenic purpura.

Fourteen adults with idiopathic thrombocytopenic purpura suffered a relapse after treatment with steroids, vinca alkaloids, or intravenous gammaglobulin. Splenic sequestration of platelets labelled with 111In-oxine was assessed, and the patients then underwent splenectomy. During follow up of four to 47 months (mean 20.7) none of the patients required further treatment, including three of 14 who showed partial relapses. Splenic sequestration patterns did not predict relapses, but an unexpected finding was that patients who relapsed had significantly smaller spleens. It is concluded that splenectomy is beneficial in most adult patients with idiopathic thrombocytopenic purpura and that radiological techniques to measure the size of the spleen may be useful in predicting which patients may relapse.

Adolescent↗
PubMed1984

Streptococcus salivarius strains carry either fibrils or fimbriae on the cell surface.

Strains of Streptococcus salivarius were screened by negative staining for the presence of surface structures. Two structural subgroups were found, carrying either fibrils or fimbriae, projecting from the cell surface. Eight strains carried a very dense peritrichous array of fibrils of two distinct lengths. Long fibrils had an average length of 175 nm, and short fibrils had an average length of 95 nm. Two strains carried only long fibrils, one strain carried only short fibrils, and another strain carried a lateral tuft of very prominent fibrils of two lengths, with a fibrillar fuzz covering the remainder of the cell surface. In all the strains in which they were present, the long fibrils were unaffected by protease or trypsin treatment. In contrast, the short fibrils were completely digested by protease and partially removed by trypsin. Neither long nor short fibrils were affected structurally by mild pepsin digestion or by lipase. The Lancefield extraction procedure removed both long and short fibrils. These twelve fibrillar strains were therefore divisible into four structural subgroups. Extracts of all the fibrillar strains reacted with group K antiserum. The second main structural subgroup consisted of nine strains of S. salivarius, all of which carried morphologically identical, flexible fimbriae arranged peritrichously over the cell surface. The fimbriae were structurally distinct from fibrils and measured 0.5 to 1.0 micron long and 3 to 4 nm wide, with an irregular outline and no obvious substructure. There was no obvious reduction in the number of fimbriae after protease or trypsin treatment. Extracts of the fimbriated strains did not react with the group K antiserum. The two serological and structural subgroups could also be distinguished by colony morphology.

Fimbriae, Bacterial↗
PubMed1979

Ferritin as a cytosol iron transport intermediate in human reticulocytes.

The major iron-bearing cytosol components of human reticulocytes identified after incubation with 59 Fe-125I-transferrin have been studied further. Component C previously found to behave consistently as an intermediate in the iron transport pathway to haem is shown to consist entirely of ferritin. After a short pulse of labelled transferrin incubation, chase experiments showed a fall of ferritin label with time and a corresponding increase in haemoglobin-iron incorporation. There was no loss of ferritin to the culture medium. Restriction of iron uptake by reticulocytes using both p-hydroxymercuribenzoate inhibition of uptake and incubation with progressively lower saturations of iron-transferrin gave linearly related incorporation of 59Fe into ferritin and haemoglobin at all levels of iron uptake, thus negating the concept of ferritin as an 'overspill' form of reticulocyte iron. The results suggest that cytosol ferritin is an obligatory intermediate in reticulocyte iron transport.

Biological Transport, Active↗
PubMed1978

The pregnant drinker.

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Abnormalities, Drug-Induced↗
PubMed1977

Does sarcoma occur in man after intramuscular iron?

Several factors influence the induction of sarcomas at the site of iron carbohydrate complex injection in high dosage, in animals. 1. Species specificity: tumours have been induced in rats, mice and hamsters but not in guinea pigs or dogs; 2. dose-response: a threshold dose may be defined and the yield of tumours increases with the dose; 3. the amount of residual iron at the injection site: the effect is a local oncogenesis; 4. the latent period relative to life span in the species: the probable latent period in man has been estimated to be 15-20 years. Since iron-dextran was introduced 22 years ago, nine malignancies in man allegedly related to iron-complex injection have been described in five reports during the period 1960-1977. A critical review of the information available on these cases suggests that in one case only is the data sufficiencyl strong to support the probability of iron-dextran induced sarcoma in man. Soft tissue tumours of the buttock are not rare: on the basis of this single case a causal relationship in man cannot yet be made.

Adolescent↗
PubMed1977

Interaction between Ferastral and plasma factors.

Ferastral, iron-poly (sorbitol-gluconic acid) complex, in aqueous solution is completely adsorbed by magnesium carbonate; Ferastral in serum solution is only partially adsorbed by magnesium carbonate. Adsorption by magnesium carbonate removes the fraction of Ferastral in serum solution which donates iron more readily to transferrin. It is suggested that this fraction comprises the smaller molecular species of the Ferastral complex and that these species have a faster rate of absorption from an intramuscular injection site than the larger molecular species of the iron complex preparation. These findings shed some light on the patterns of serum transferrin bound iron compared with serum Ferastral concentrations which occur with time after intramuscular Ferastral injection.

Adsorption↗
PubMed1977

The assay of iron-poly (sorbitol-gluconic acid) complex (Ferastral) and its separation from transferrin in serum.

A new iron-poly (sorbitol-gluconic acid) complex (Ferastral) has been studied. A method of assay is described. The iron complex may be separated from serum transferrin using a Sephadex DEAE A50 column. This binds the iron complex and elutes iron-transferrin which can then be assayed. It is shown that the assay of serum transferrin unsaturated binding capacity using excess 59FeCl2 and MgCO3 adsorption, is valid in the presence of Ferastral. Serum unsaturated iron binding capacity may therefore be used to follow the binding of Ferastral iron by transferrin. These methods may be used to follow the distribution of iron in plasma after an intramuscular injection of Ferastral.

Chromatography, Ion Exchange↗
PubMed1977

Transfer of iron from Ferastral and other organic complexes to transferrin as measured by reticulocyte uptake.

The transfer of iron from the iron carbohydrate complexes, Ferastral, Imferon, and Jectofer, and from ferric chloride has been studied by the effect of such transfer in reducing reticulocyte uptake of 59Fe from labelled transferrin. There are plasma factors which augment the transfer of iron from complex to transferrin. The pattern of transfer from Ferastral and from Imferon are similar: at concentration of 5000 microgram/100 ml and 1250 microgram/100 ml in plasma these complexes transfer about 0.8% and 1.7%, respectively. Jectofer transfers about four times these amounts under similar conditions. In the case of Ferastral there is evidence of an equilibrium between transferrin-bound and Ferastral-bound iron. The characteristics of Ferastral assessed in this way suggest that it may prove suitable for therapeutic use as a total dose infusion.

Cells, Cultured↗
PubMed1977

Patterns of plasma iron fractions after intramuscular Ferastral.

The distribution of plasma iron fractions after intramuscular Ferastral is described for times up to eight days after injection. Transferrin-bound iron reaches a peak value in 4-8 hours and falls towards normal values while circulating iron-complex concentration remains high. The peak concentration of iron-complex occurs 8-24 hours after injection, and is virtually cleared from the circulation in 6-8 days. An approximate T 1/2 of 30 hours for plasma Ferastral is deduced from the rate of fall from peak values. UIBC values fell as transferrin-bound iron increased, but did not reach zero in any subject studied.

Drug Combinations↗
PubMed1975

Manpower training and child-development services.

Making quality child-development services available for children of mothers in one vocational training program significantly improved the mothers' performances. On the average, mothers with children receiving these services stayed in the Job Corps longer and more frequently completed their vocational training program. Since longer length of stay and program completion show a positive correlation with a better chance of placement and higher initial wage, the new Job Corps program improves a mother's potential for economic self-sufficiency. In addition, mothers in the program are able to learn how to better understand their children and provide for their needs. Nonresident mothers in the new mother-and-child program performed as well as resident mothers. This similarity points towards the widespread potential for initiating similar programs in many vocational training and educational settings. If, as in the Job Corps program, providing quality child-care arrangements for mothers in such settings as high schools, colleges, other manpower training programs, prisons, and places of employment can improve the mother's general motivation, enhance her earning capacity, and improve her ability to be a good mother, then dollars invested in these programs will show a high return.

Adolescent↗