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Biomedical subjects

A R Wilson

Publications and source records attributed to A R Wilson.

14 recordsLinked to original sources
PubMed1992

A statistical model and computer program to estimate association constants for the binding of fluorescent-labelled monoclonal antibodies to cell surface antigens and to interpret shifts in flow cytometry data resulting from alterations in gene expression.

Flow cytometry is used to obtain estimates for the distribution of fluorescent ligands bound to cell surface receptors throughout a cell sample. The equipment used provides light scattering parameters and also cell staining data in the form of dot plots and histograms of fluorescence intensities and the frequency of occurrence of particular fluorescence intensities. It is then assumed that fluorescence intensity is proportional to the number of labelled ligands bound to surface receptors. In this paper we present an outline of a statistical theory to account for the stretching and translation of such flow cytometry profiles which occur either as a result of alterations in gene expression, or from changing the sub-saturating concentration of fluorescent-labelled monoclonal antibodies or lectins used to stain the cells. We describe how the theory has been incorporated into two programs CSAFIT (cell surface antigen fit) and MAKCSA (make data to test CSAFIT). The program CSAFIT can be used to estimate two parameters, alpha and beta, by constrained non-linear regression analysis of the flow cytometry profiles. If the shift results from changes in the concentration of a staining agent then the estimates alpha and beta calculated by CSAFIT are functions of the ligand concentration, the ligand type and the cell line characteristics. They quantify the stretch and translation events that are encountered in flow cytometry. So when the parameter estimates alpha and beta are then further analysed as functions of ligand concentration, estimates for the average association constant K for the binding-site/ligand interaction can be obtained. This paper describes details of the development of programs CSAFIT and MAKCSA. We also discuss the distribution of parameter estimates calculated by CSAFIT and the overall performance of CSAFIT as assessed by simulation studies using data generated by MAKCSA.

Antibodies, Monoclonal↗
PubMed1992

Thrombolytic therapy of synthetic graft occlusions before vascular reconstructive procedures.

The objective of this study was to evaluate the impact of thrombolysis of synthetic grafts before urgent vascular reconstruction. In 29 patients, 41 thrombosed synthetic grafts that underwent intraarterial thrombolysis were studied. The cases were divided into three groups: group I--complete thrombolysis followed by reconstruction; group II--complete thrombolysis alone; and group III--incomplete lysis requiring reconstruction or sympathectomy. Follow-up ranged from 1 to 556 days (mean: 149 days). Kaplan-Meier analysis was used to determine patency and limb salvage rates. One-year patency and limb salvage rates were 53% and 95%, 34% and 67%, and 38% and 48%, respectively, for groups I, II, and III. Eighteen complications occurred in 16 of the 41 (39%) episodes. One patient died of intracranial hemorrhage. The best results were achieved when complete lysis was followed by appropriate reconstruction. Patency was equally poor in complete thrombolysis alone and reconstructions required by incomplete thrombolysis. Limb salvage was better after complete thrombolysis, regardless of the appropriate reconstruction.

Aged↗
PubMed1990

Mammography in the pre-operative assessment and post-operative surveillance of patients treated by excision and radiotherapy for primary breast cancer.

To evaluate the place of mammography in the selection of patients for excision and radiotherapy for primary breast cancer a detailed analysis of pre-operative mammograms was performed in (i) a study group of 37 patients who developed local recurrence; (ii) a matched control group with a median local recurrence free survival of 57 months. There were significantly more multifocal tumours in the study group. Tumours were significantly larger (P = 0.02) and closer to the nipple (P = 0.008) in the study group compared to the control group. Regular follow-up mammograms were available in 26 of the study group. Twenty-one patients had mammographic evidence of either residual or recurrent tumour. We conclude that pre-operative mammography is essential in the selection of patients for excision and radiotherapy. Following treatment, mammography is useful in detecting residual or recurrent disease.

Adult↗
PubMed1989

Acquired coronal cleft vertebra.

Five patients with acquired coronal clefts in lower lumbar vertebral bodies are presented. The appearances on plain radiographs, skeletal scintigraphy, discography, computed tomography and magnetic resonance imaging (MRI) are described. The aetiological factors are discussed with particular emphasis on the role of the intervertebral disc and the discovertebral junction in the pathomechanics of vertebral body injury. Magnetic resonance imaging was helpful in the radiological assessment and provided information from which an explanation of the clefts could be proposed.

Adult↗
PubMed1988

Ventilatory function during urography: a comparison of iopamidol and sodium iothalamate.

The effects on respiratory function during intravenous urography of the ionic contrast medium sodium iothalamate and the non-ionic contrast medium iopamidol were compared. Forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC) were recorded in 37 non-atopic patients referred for intravenous urography. Nineteen patients received iopamidol and 18 patients received sodium iothalamate. Both the sodium iothalamate and the iopamidol groups showed a significant fall in FEV1 and FVC (P less than 0.001). The reductions in FEV1 and FVC were comparable and were not symptomatic. The differences in the percentage changes of the FEV1 and FVC in the iopamidol and the sodium iothalamate groups were not statistically significant (P greater than 0.5 and P greater than 0.1 respectively). No significant change in the ratio of the FEV1 and the FVC was demonstrated in either the iopamidol or the sodium iothalamate groups. Both the ionic and the non-ionic contrast media produced a measurable but asymptomatic and biologically insignificant fall in static ventilatory function. Bronchospasm does not appear to be an important contrast-induced effect in non-atopic individuals. Iopamidol offers no advantage over sodium iothalamate with respect to ventilatory effects in non-atopic patients undergoing intravenous urography.

Adult↗
PubMed1979

Role of bovine serum albumin in the nutrition of Mycobacterium tuberculosis.

Bovine serum albumin promotes the growth of small inocula of Mycobacterium tuberculosis in media containing unesterified fatty acids. Albumin binds fatty acids present in concentrations toxic for the organisms. In the present study, additional roles of albumin were investigated. When present in a basal medium, fatty acid-free albumin could be utilized by M. tuberculosis as a sole source of carbon. Since albumin could not substitute for the amino acids in basal medium as a nitrogen source, it was concluded that the protein component in albumin was not utilized as a nutrient by the organisms. An ether extract of fatty acid-free albumin supported a small but significant amount of growth. Analysis of the lipids in fatty acid-free albumin by gas chromatography revealed the presence of 686 microgram of fatty acid per g of albumin. Although a small amount of growth occurred when a lipid extract of albumin was present in the medium, growth stimulation was dependent in major part on the presence of undenatured albumin in the medium. Lipids, when bound to albumin, can serve as a nontoxic source of carbon and energy.

Culture Media↗
PubMed1978

A new method for the simultaneous assay of rosette-forming and antibody-secreting cells, utilising immune adhesion reactions in monolayer.

Mixtures of sheep erythrocytes and immune spleen cells from mice were incubated in shallow slide chambers coated with erythrocyte ghosts or anti-mouse Ig, with poly L-lysine as a coupling agent. Antigen-binding cells and erythrocytes surrounding antibody-releasing lymphocytes became bound to the reactive surfaces by immunocytoagglutination and could be readily observed on inversion of the chambers. The sensitivity of the method compares with those currently in use for quantification of antibody-releasing cells, and resolution of rosettes is markedly superior to that obtainable in other assay systems. The advantages and limitations of the method are discussed.

Animals↗
PubMed1976

Cardiopulmonary changes during flexible fiberoptic bronchoscopy.

Changes of pulse rate and arterial blood gases were measured before, during, and after fiberoptic bronchoscopy in eleven patients with resting arterial PO2 breathing room air of 75 mm Hg or greater. Tachycardia was greatest after anesthesia (mean change greater than 20 beats/min) and declined thereafter. Hypoxemia was progressive from the time of entrance of the bronchoscope into the respiratory tree and continued into the immediate postbronchoscopic period when the mean fall was about 16 mm Hg. Mild hyperventilation was noted under all conditions. Since progressive hypoxemia persists following removal of the instrument and does not occur during rigid bronchoscopy, direct irritation causing reflex bronchospasm and the effects of aspirated secretions, anesthetic or lavage must be considered as possible causes for the hypoxemia.

Adult↗
PubMed1976

Evaluation of carrageenan as an immunosuppressive agent and mediator of intravascular coagulation.

Carrageenan suppressed antibody responses to SRBC in mice and rats, measured in terms of splenic IgM PFC production. The effect, in mice, was dependent on dose and on the temporal relationship between treatment and antigen administration. Carrageenan was found to alter the time course of the PFC response and also to produce disseminated intravascular coagulation. Some correlation between the observed effects and the use of chemically distinct carrageenans was found. The possible mode of action of carrageenan is discussed in the light of these, and other findings.

Animals↗
PubMedDate not supplied

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Schools, Veterinary↗