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Biomedical subjects

D W Dawson

Publications and source records attributed to D W Dawson.

At least 37 records · Page 2Linked to original sources
PubMed1981

Vitamin B12 quality control trials.

The results of regional quality control trials of vitamin B12 assays are reported. Consideration is given to the materials suitable for such trials. The technical and clinical performance of the participants are assessed together with the methods used. The introduction of a target coefficient of variation has produced better identification of good and bad performance and the use of a reference serum has permitted comparison of assays of different methods. The linearity of most methods is suspect and indicates the need for reference sera of varying concentration. Introduction of kits has not generally improved precision and variation between laboratories shows the use of kits can be improved.

England↗
PubMed1980

An evaluation of commercial radioisotope methods for the determination of folate and vitamin B12.

Five commercial kits for the determination of folate and six kits for the determination of vitamin B12 were investigated. Their performance has been compared with microbiological methods for the two vitamins and with a non-commercial radioisotopic method for B12. The results show the importance of the determination of the reference range for an individual laboratory for each method. The precision of the kits varied appreciably, as did their performance using specimens from patients with different haematological disorders. In particular, certain kits failed to detect all patients with pernicious anaemia. The relative accuracy of the kits was assessed. Various factors which should be taken into account in the final selection of a satisfactory kit are discussed.

Anemia, Pernicious↗
PubMed1977

A regional quality control trial of folate assays.

A regional quality control trial of folate assays is described. It is concluded that the trial is practical and useful in allowing inter-laboratory comparison of results, promoting discussion, and improving precision but it is impossible to assess accuracy. It was of no use in the comparison of assay methods, probably on account of the small number of laboratories participating.

Blood Chemical Analysis↗
PubMed1977

Evaluation of a commercial radioisotopic kit for folate assays.

A commercial kit for the radioisotopic assay of folate in serum, the Bio-Rad 'Quanta Count' folate kit, produced lower results than the Lactobacillus casei microbiological assay method. Its normal range was 2-0-13-0 microng/l and the reproducibility was similar to that of the microbiological assay method. The kit was also satisfactory for whole bood folate assays. The cost requires careful consideration before the kit is used for routine purposes.

Biological Assay↗
PubMed1975

Changes in erythroblast morphology as an index of response to cyanocobalamin in patients with megaloblastic anaemia.

Fifty-three patients with megaloblastic anaemia treated with cyanocobalamin and folic acid have been studied. Repeat marrow examination was found to be of value in assessing response to treatment. The early improvement in marrow morphology in patients with pernicious anaemia was greater with 1000 mug than with 5 mug doses of cyanocobalamin. The effect of folate deficiency in delaying marrow response to cyanocobalamin in patients with pernicious anaemia is described and combined cyanocobalamin and folic acid treatment was found to be more effective than either alone. The response to large doses of cyanocobalamin in folate deficient patients was unrelated to the initial serum vitamin B12 level.

Adult↗
PubMed1968

Plasmacytoma of the thyroid.

Three cases of plasmacytoma of the thyroid are described and their clinical and histological features recorded. Two were considered to be true extramedullary plasmacytomas, the third the initial manifestation of a disseminated myelomatous process. Plasmacytomas of the thyroid are shown to have many features in common with malignant lymphomas in this site, including an association with Hashimoto thyroiditis in more than half the reported cases. No certain method of assessing the prognosis in any individual case has yet been described.

Adult↗