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Biomedical subjects

S Roath

Publications and source records attributed to S Roath.

At least 37 records · Page 2Linked to original sources
PubMed1987

Transient acquired blood group B antigen associated with diverticular bowel disease.

Transient acquired B red cell antigen was found in a patient with inflammatory bowel disease. Removal of the affected portion of the bowel was associated with disappearance of the B antigen. This phenomenon has usually been recorded in association with neoplasms of the bowel, but appears to be a marker for the release of bacterial enzymes into the systemic circulation associated with breakdown of the normal bowel barrier to such materials.

ABO Blood-Group System↗
PubMed1985

Lymphocyte labelling with indium: cytotoxicity studies.

Viability studies on lymphocytes labelled with indium In111 using oxine as a ligand showed impairment as measured by trypan-blue assessment and rosetting ability. In addition, lymphocyte response to phytohaemagglutinin stimulation as measured by tritiated-thymidine uptake was also impaired at levels where adequate cell labelling had taken place. Cadmium toxicity was not noticed, and the use of tropolone as a ligand offered possibilities of reduced cellular toxicity. Such cytotoxicity may not have been important in earlier reported studies on granulocytes where the large numbers available for in vivo work and the short periods of study still allowed useful conclusions to be drawn. However, because of the prolonged lifespan of the human lymphocyte, the cytotoxic effects of the processing might well make the long-term studies which would be of interest much less reliable for clinical assessment.

Cytotoxicity, Immunologic↗
PubMed1985

The morphology and viability of blood components processed by high-gradient magnetic separation.

The effect of high-gradient magnetic separation on blood components has been investigated. For erythrocytes there is no significant change in the morphology, size distribution and in the in-vivo survival times at the confidence level P = 0.05. For neutrophils stimulated nitro-blue tetrazolium reduction is maintained after HGMS. No change in chemotaxis and yeast cell phagocytosis was observed. Platelet distribution curves show no detectable changes before and after filtration. It is concluded that blood separated by HGMS is suitable for diagnostic analysis and may be considered for return to the patient.

Animals↗
PubMed1984

The acute effects of nifedipine on red cell deformability in angina pectoris.

In a randomised double-blind study, the effects on red cell deformability of a single sublingual dose of nifedipine were compared with placebo in eight patients with stable angina pectoris. Red cell deformability, measured by filtration and centrifugation techniques, was significantly increased at rest in all eight patients 1 h after nifedipine, while no change occurred after placebo. The improvement in deformability after nifedipine was maintained at the end of a period of exercise and unchanged from resting values after placebo. The results suggest that the increased deformability of red cells after nifedipine could contribute to the therapeutic effects of the drug in myocardial ischaemia.

Aged↗
PubMed1984

Assessment of therapeutic control of anticoagulation.

The control achieved in two anticoagulant clinics over 1 year was studied. The result of 430 patient years of treatment in 732 patients was assessed. Overall, the patients were maintained in the therapeutic range (British ratio 2.0-4.0) 85% of the time, 'under-anticoagulated' 10% and 'overtreated' 5% of the time. Patients on long-term treatment had better control than those on short-term treatment (87 and 72% of time in therapeutic range, respectively). Short-term patients were 'undertreated' one quarter of the time. Assessment of the percentage of time individual patients spent within the therapeutic range was a useful index: 77% short-term patients and 99% long-term patients were controlled more than half the time; and 30% short-term plus 40% long-term patients were controlled all the time. Two complementary methods of assessing therapeutic control are used. The standard of control compares favourably with other reports, but shows areas where improvements can be made. For assessment of clinical benefit from anticoagulants, close quality control of treatment by such methods is essential.

Adolescent↗
PubMed1983

The relationship between cyclic AMP changes and histamine release from basophil-rich human leucocytes.

Histamine release and changes in cyclic AMP levels induced by a variety of stimuli have been measured in isolated human leucocytes from a patient with 40-70% basophilia. Adenosine and sodium fluoride induced early monophasic rises in cyclic AMP which peaked at 1 min, but they did not release histamine. 2',5'-Dideoxyadenosine (DDA) caused a transient fall in cyclic AMP levels. Anti-IgE, polylysine and calcium ionophore A23187 induced a slow release of histamine commencing 2-5 min after addition of secretagogue. With polylysine and A23187, release was still proceeding 45 min after challenge. In contrast, the chemotactic peptide formyl-methionyl-leucyl-phenylalanine (f-met-leu-phe) induced a rapid secretion of histamine which was complete within 2 min. Anti-IgE induced a rapid monophasic rise in cyclic AMP which reached a maximum at 45 sec and was inhibited by pretreatment with DDA. Cyclic AMP rises induced by polylysine and f-met-leu-phe were kinetically similar but smaller in magnitude. A23187 caused a later rise in cyclic AMP which peaked 3 min after challenge. A high concentration (50 microM) of compound 48/80 induced a slow cytotoxic release of histamine which was not accompanied by changes in cyclic AMP levels. The inconsistent quantitative and kinetic relationships of histamine release and cyclic AMP production suggest that changes in cyclic AMP levels may not play a key role in the biochemical events leading to mediator secretion from human basophil leucocytes.

Adenosine↗
PubMed1983

The evaluation of neutropenia: the use of the granulocyte mobilization test.

Ten individuals with idiopathic neutropenia and similar numbers of normal and abnormal controls were tested for mobilization of their marginal granulocyte pools and bone marrow reserve by using epinephrine and hydrocortisone intravenously. Individuals with 'benign' idiopathic neutropenia appeared to have a normal response while half the abnormal controls responded poorly. It is suggested that granulocyte mobilization tests are valuable in the assessment of individuals with neutropenia.

Adult↗
PubMed1983

Impairment of neutrophil chemotaxis by serum from patients with chronic lymphoproliferative disease.

The sera of 74 individuals with chronic lymphoproliferative disease were screened for the presence of inhibitory activity against neutrophil chemotaxis. This was present in more than half the patients with IgA myeloma and Hodgkin's disease but was less common in chronic lymphocytic leukaemia, lymphocytic lymphoma and non-IgA paraproteinaemia. Heating the sera prior to testing frequently enhanced inhibitory activity particularly in myeloma and lymphoma.

Blood↗
PubMed1982

The comparison of 8-hydroxyquinoline, tropolone, and acetylacetone as mediators in the labelling of polymorphonuclear leucocytes with indium-111: a functional study.

Tropolone forms a lipophilic complex with indium-111 which is capable of mediating the labelling of polymorphonuclear leucocytes (PMNs) by this isotope; labelling efficiencies are comparable with the best achieved using 8-hydroxyquinoline and acetylacetone. However, in terms of PMN chemotaxis and phagocytosis, tropolone is significantly less toxic than either of te other ligands. 8-Hydroxyquinoline was found to reduce PMN chemotaxis and phagocytosis to approximately 70% of the control values at a concentration of 20 micro M. Tropolone may prove a superior labelling reagent.

Chemotaxis, Leukocyte↗
PubMed1982

Granulocyte chemotaxis: multiple assay screening using a raft technique.

The assessment of granulocyte chemotaxis is complicated by the difficulty of precisely reproducing results in serial estimations and deciding on the best end point which would reflect most accurately the degree of travel taken by the cells under observation. The methods in use are generally based on the Boyden chamber, following this, we have further developed the principle of the "raft" technique of chamber based migration. In order to overcome the problems associated with reproducibility of results when performing multiple assays of chemotaxis, especially when sera of widely differing activity are encountered in the screening procedure, we have used a "batching" system and a simple method of presenting the results so that they are comparable.

Chemotaxis, Leukocyte↗
PubMed1981

Blood thixotropy.

Explore the source record for details and available documents.

Blood Viscosity↗
PubMed1979

B-cell acute lymphatic leukaemia: immunoglobulin synthesis, morphology and clinical features.

A detailed case study of a B cell acute lymphocytic leukaemia (ALL) is described. Ultrastructurally the neoplastic cells resembled other cases of ALL studied. The majority of the neoplastic cells had detectable surface IgGlambda and receptors for Fcgamma while a majority of the cells had receptors for the C3 component of complement. Neoplastic cell preparations were able to synthesize IgGlambda with a surplus of free lambda chains. This case did not respond to treatment, and death ensued within 36 h of presentation. The clinical and laboratory findings are discussed with respect to other cases of ALL.

Adult↗
PubMed1978

Differential blood cell separation using a high gradient magnetic field.

A technique for the separation of erythrocytes from whole blood is described which exploits the magnetic property of haemoglobin in the reduced state. The technique is characterized by the use of a filter consisting of a cylinder, containing stainless steel wire mesh, placed between the jaws of an electro magnet. When activated, the electromagnet induces a magnetic field gradient in the vicinity of each of the constituent wires, sufficient to attract and trap erythrocytes in suspension. The number of erythrocytes captured varies with the applied field (0-1.4 Tesla in these experiments) and flow rate (1.9-12.9 x 10(-4) m s-1). The capture process does not cause haemolysis or observable surface damage to the erythrocytes and neither leucocytes nor platelets are retained by the filter.

Cell Separation↗