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Biomedical subjects

B J Bain

Publications and source records attributed to B J Bain.

At least 91 records · Page 5Linked to original sources

The association of age with dosage requirement for warfarin.

Two groups of patients have been studied in order to investigate the relationship between age and the effect of oral anticoagulant therapy. The first group comprised 364 patients aged 23-89 years who showed a stable anticoagulant effect on medium- or long-term warfarin therapy; in this group the elderly subjects were found to require, on average, a lower drug dose to maintain the same degree of anticoagulation. The second group comprised 130 patients aged 15-83 years who had received an initial standard oral dose of 10 mg of warfarin. No significant difference was found in the degree of anticoagulation achieved by 16 hours. Although the maintenance dose in elderly patients is somewhat lower than in younger, the same protocols can be used for the introduction of therapy.

Administration, Oral↗

Acute changes in atherogenic and thrombogenic factors with cessation of smoking.

Tobacco smoking is associated with alterations in several factors considered to be important in the atherosclerotic process. Thirty chronic smokers were studied 2 weeks before and 2 weeks after complete tobacco withdrawal. Significant reductions in fibrinogen, haematocrit, plasma viscosity and whole blood viscosity as well as a significant increase in HDL-cholesterol were observed. As these factors are important in both atherogenesis and thrombogenesis, these observations may give insight into tobacco-induced atherosclerotic disease and may be responsible for the more rapid reduction in the incidence of cardiovascular disease that is believed to occur after stopped smoking.

Adult↗

Prediction and diagnosis of sickling disorders in neonates.

A pilot scheme for the prediction and detection of sickle cell disease in neonates was set up and the results from its first three years of operation analysed. A total of 153 women booking at the antenatal clinic were found to have haemoglobin S. The protocol required that all partners of the women so identified be screened for abnormal haemoglobins and beta thalassaemia trait, and that the babies of these women should have cord blood electrophoresis performed. In fact this was only achieved in 75 partners (49%) and 91 of 145 infants (63%). Of 10 babies born with sickle cell disease during the study period, nine had mothers known to have haemoglobin S or C, but only four of these mothers' partners had been tested before delivery of the child. This pilot study highlights the problems in establishing effective antenatal screening programmes, especially in ethnic minority groups. The results show that detailed staff training, careful organisation of administrative arrangements, and education of 'at risk' groups should all be undertaken before the launching of major screening initiatives.

Anemia, Sickle Cell↗

Screening of antenatal patients in a multiethnic community for beta thalassaemia trait.

An investigation of the reliability of screening tests for beta thalassaemia trait in pregnant women was carried out as part of a programme to predict beta thalassaemia major in the fetus. Women with a mean corpuscular volume (MCV) of less than 83fl were examined further, and the reliability of various red cell indices as screening tests was assessed and compared. Over three years 696 women were found to be microcytic and were investigated further. If no abnormal haemoglobin was found by cellulose acetate electrophoresis at alkaline pH, haemoglobin A2 estimation was performed. Beta thalassaemia trait was diagnosed in 56 (8%) of the microcytic women. Both the MCV and the mean corpuscular haemoglobin (MCH) were found to be suitable screening tests for detecting patients who required further investigation. Women found to have beta thalassaemia trait or a functionally equivalent disorder were of varied ethnic origins. Of 58 such women, partners were investigated in 45 instances, and three pregnancies at risk of beta thalassaemia major were identified. Investigations for beta thalassaemia trait should preferably be carried out before pregnancy but for those already pregnant investigation should be carried out, irrespective of whether the patient seems to be iron deficient. It is advisable that partners of women with beta thalassaemia trait have hemoglobin electrophoresis, whatever their red cell indices, as double heterozygosity for either haemoglobin S or haemoglobin E and beta thalassaemia may produce severe disease.

Erythrocyte Count↗

Platelet count and platelet size in healthy Africans and West Indians.

Healthy subjects of African origin were found to have lower platelet counts than simultaneously studied healthy Caucasians. A similar reduction was found in a large group of West Indian females, though not in a small group of West Indian males. It is suggested that the lower platelet counts observed in Africans and West Indians may be partly environmental and partly genetic in origin. The mean platelet volume and platelet distribution width in the Africans and West Indians showed the same relationship with the platelet count as was found in Caucasians, so that the same nomograms can be used in all ethnic groups to assess whether there is deviation from normality.

Africa↗

An assessment of the three-population differential count on the Coulter Counter Model S Plus IV.

The accuracy and precision of a three-population differential count on a Coulter Counter S Plus IV were assessed. In general a good correlation was found between manual and automated lymphocyte and granulocyte percentages although various abnormal samples caused discrepancies, and it was found that some eosinophils were categorized as mononuclear cells rather than granulocytes. The automated mononuclear cell percentage was found to be imprecise and often inaccurate as a reflection of monocyte numbers. The instrument sometimes failed to either reject or 'flag' samples containing an appreciable percentage of lymphoma cells, nucleated red blood cells, blast cells, or eosinophils but was found useful in reducing the number of differential counts required.

Adult↗

The use of hydroxocobalamin in the Schilling test.

Hydroxocobalamin and cyanocobalamin have been compared as the 'flushing dose' in the Schilling test. In healthy, haematologically normal subjects excretion of the test dose was greater following a hydroxocobalamin flushing dose than following a cyanocobalamin flushing dose, and to a lesser extent this was also true in patients requiring investigation. There were occasional discrepant results, but in general it appears that, although reference values differ, hydroxocobalamin is a suitable replacement for cyanocobalamin in the Schilling test.

Adult↗

A comparison of the white cell counts of cord blood from babies of different ethnic origins.

Cord blood samples were collected from 242 babies of five different ethnic groups. All had a birth weight of at least 2.5 kg, but they were otherwise unselected. No ethnic differences were found in the total white cell count, neutrophil, lymphocyte, monocyte or eosinophil counts. Thus the lower total white cell and neutrophil count which has been observed in adults of African and Afro-Caribbean origin is not present in neonates. Similarly eosinophil counts did not differ between the different ethnic groups suggesting that high eosinophil counts previously reported in Indian and African subjects have an environmental cause.

Asian People↗

Platelet count and platelet size in males and females.

The platelet count of healthy males was compared to that of healthy females. A higher platelet count in women was confirmed. A similar inverse non-linear relationship between the platelet count and the mean platelet volume (MPV) was found in the two sexes. The slightly higher MPV in men was insufficient to compensate for the lower platelet count so that the plateletcrit, which measures total volume of platelets in a given volume of blood, was also significantly higher in women.

Adolescent↗

Assessment of the value of a competitive protein binding radioassay of folic acid in the detection of folic acid deficiency.

The diagnostic value of the Becton Dickinson Radioassay Kit (125I) for the the assay of red cell folate has been investigated. The assay was acceptable with regards to precision but was non-linear with changing packed cell volume. Sensitivity of the assay was satisfactory, with 24 of 25 folate deficient patients giving red cell folate values which fell below the reference range. Specificity of the assay in the detection of folate deficiency was less satisfactory. As with microbiological assays, a considerable proportion of vitamin B12 deficient patients had low red cell folate values. In addition, low concentrations were found in 12% of patients who were unlikely to be deficient in either vitamin B12 or folic acid.

Binding, Competitive↗

Some influences on the ESR and the fibrinogen level in healthy subjects.

In healthy subjects the ESR is higher in women than in men, and in both sexes a rise with age occurs. It is well established that pathological elevation of the ESR may be due to elevation of the fibrinogen level. The present study has shown that in normal subjects the ESR correlates not only inversely with the haemoglobin level but also directly with the fibrinogen level. These two factors together explain the difference in ESR between men and women, and the major part of the age-related increase in the ESR. Fibrinogen levels were found to be significantly higher in male smokers than male non-smokers, and in women were inversely correlated with alcohol consumption; despite this the ESR did not differ in smokers and non-smokers, nor was it related to alcohol intake. Oral contraceptive intake influenced neither the fibrinogen level nor the ESR. The correlation of ESR and fibrinogen concentration in healthy subjects suggests that physiological variation in the ESR is determined by the fibrinogen concentration as well as the haemoglobin level.

Adolescent↗

An assessment of the Coulter Counter Models S Plus II and III.

The Coulter Counter Models S Plus II and III have been evaluated. No serious safety hazards were identified. Scientific assessment showed some non-linearity in the Hb which caused the MCH and MCHC to vary as samples were diluted. Precision and carry-over were satisfactory. The results obtained compared well with those of the Coulter Counter Model S, except for WBC; reference methods showed better accuracy on the Models S Plus II and III. Platelet counts agreed with those by phase-contrast microscopy and the lymphocyte percentage was similar to that from the blood film except in the lymphoproliferative disorders. The whole blood and pre-dilute modes gave similar results though the platelet count was slightly higher in the whole blood mode. In the National External Quality Assessment Scheme results were in accordance with those from other Model S Plus Users. Time did not allow a detailed evaluation of the cell volume distribution curves but it was noted that the white cell profile was useful for detecting platelet aggregation. Efficiency assessment showed throughputs of 66 and 93 samples per hour on the Models S Plus II and III respectively. The platelet count was clinically useful as was the lymphocyte percentage measurement which rendered some differentials unnecessary. Rejection of the white cell profile was a helpful index of abnormality on the Model S Plus II but occurred non-specifically on the Model III tested.

Adult↗

Sideroblastic anaemia in association with malignant histiocytosis.

A 69-year-old women died of malignant histiocytosis in association with sideroblastic anaemia. Respiratory insufficiency was a prominent clinical feature and was found to be due to obstruction of pulmonary capillaries by malignant histiocytes. It is possible that the same abnormal myeloid clone gave rise to malignant histiocytosis and sideroblastic anaemia.

Aged↗

Megakaryoblastic leukemia presenting as acute myelofibrosis -- a study of four cases with the platelet-peroxidase reaction.

Acute myelofibrosis (AM) or malignant myelosclerosis is a myeloprofilerative syndrome in which bone marrow fibrosis is associated with a proliferation of immature myeloid cells. In four patients with typical AM, investigated by the platelet-peroxidase reaction at ultrastructural level, the blast cells were found to be megakaryoblasts. One patient, treated with the drug combination DAT, achieved a complete remission of 5 mo duration. This study supports the view that megakaryoblastic leukemia is the most frequent underlying cause of AM and proposes that it should be classified as a form of acute myeloid leukemia.

Acute Disease↗