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Biomedical subjects

D Logan

Publications and source records attributed to D Logan.

30 records · Page 2Linked to original sources

Heterogeneity of drug-dependent platelet antigens and their antibodies in quinine- and quinidine-induced thrombocytopenia: involvement of glycoproteins Ib, IIb, IIIa, and IX.

The molecular nature of platelet receptors for quinine- and quinidine-dependent antiplatelet antibodies (Q.Ab and Qd.Ab) was studied by immunoblotting. One Q.Ab caused quinine-dependent IgG binding to platelet proteins with molecular weights (mol wts) of 174 Kd and 93 Kd and another to only a 93-Kd protein. A third Q.Ab caused binding to 174-, 140-, 93-, and 57-Kd proteins, while a fourth Q.Ab and a Qd.Ab caused IgG binding to 174- and 18-Kd proteins. Using platelets from patients with Glanzmann's thrombasthenia or Bernard Soulier syndrome and purified GPIIIa, these proteins were shown to be GPIb, GPIIb, GPIIIa, GPIX, and an unidentified 57-Kd protein missing in Bernard Soulier syndrome. Binding to the 93-Kd protein was independent of the PIA1 antigen. Absorption of one Q.Ab with Glanzmann's thrombasthenia platelets revealed different populations of antibodies with different specificities within the one patient. Thus Q.Ab and Qd.Ab are heterogeneous and may be directed toward different epitopes on major platelet glycoproteins.

Antigens, Differentiation

Analysis of immunoglobulins that bind to platelets from serum of patients with immune thrombocytopenia: molecular weight distribution.

The nature of platelet- bindable immunoglobulins (PB-Ig) in serum has been investigated. PB-IgG, -A and -M were measured by an ELISA using platelets coated on microtitre plates. This assay detected alloantibodies at high serum dilutions. In 32 patients with idiopathic thrombocytopenic purpura (ITP) or systemic lupus erythematosus (SLE) raised levels of at least one PB-Ig class were found in 18. To distinguish binding due to immune complexes, the molecular weight of PB-IgG was studied by gel filtration on Sepharose 4B. In sera from patients with ITP and SLE, PB-IgG with Mr of primarily 150 Kd was observed, compatible with monomeric IgG antiplatelet antibodies. Levels of PB-IgG in serum were not related to total serum IgG. In sera from the patients with SLE and some with ITP (most of whom had several of the features of SLE), PB-IgG with Mr of 200 Kd - greater than 1000 Kd was seen. In heat-aggregated preparations of normal IgG, PB-IgG with Mr up to 1000 Kd was also found. Rabbit IgG was able to block PB-IgG in fractions of high molecular weight in purified normal IgG, heat-aggregated normal IgG and in patient serum, but had no effect on the 150 Kd peak. In whole serum from patients who had high molecular weight PB-IgG, the inhibitory effects of rabbit IgG were much less than in isolated high molecular weight column fractions. Thus although the majority of PB-IgG is monomeric antiplatelet antibody, some PB-IgG with higher molecular weight, characteristic of immune complexes, occurs in sera of some patients with autoimmune thrombocytopenia and it makes a small contribution to PB-IgG levels measured in whole serum.

Animals

The role of myo-inositol in multiple sclerosis.

Myo-inositol was given orally to nine multiple sclerosis patients and nine healthy control subjects. Pattern reversal evoked potential testing was used to assess its effect. The principal positive wave increased in amplitude, duration and area in a dose-dependent manner in the multiple sclerosis group compared with controls. Cerebrospinal fluid concentrations of myo-inositol in multiple sclerosis and controls were similar. The significance of these observations is discussed in relation to recent discoveries in inositol phospholipid function.

Adult

Experience with bladder training in 65 patients.

The results of in-patient bladder training in 65 women with frequency, urgency and urge incontinence are reported. There was a good initial response in 88%. By 6 months the response rate had fallen to 38%. Patients with sensory urgency appeared to do better than those with detrusor instability and it is suggested that bladder training may be indicated as primary treatment in sensory urgency. Eysenck Personality Inventory testing was carried out in 43 patients. The mean neuroticism score was high, with non-responders having a higher neuroticism score than responders. Patients with detrusor instability had a higher mean neuroticism score than those with sensory urgency. Introverted patients appeared to do better than extraverts with bladder training.

Adolescent

Comparison of left ventricular ejection fraction by EKG-gated radionuclide techniques and contrast angiography using a microcomputer system.

The left ventricular ejection fractions of 53 patients were determined from multi-image cardiac blood pool scintigrams in the left anterior oblique position utilizing a microcomputer and floppy disc. These data were compared to ejection fractions obtained at cardiac catheterization in the right anterior oblique position. The ejection fraction obtained by radionuclide technique was comparable to that obtained by contrast angiography in the 53 patients with an r = 0.93. Forty-five patients with coronary artery disease showed an r = 0.92. In the coronary artery group with regional wall dysfunction, the correlation was r = 0.89.

Angiography

First-pass or single-pass radionuclide angiography evaluation of left ventricular ejection fraction using a microcomputer system.

Left ventricular ejection fractions of 31 patients determined from first-pass or single-pass radionuclide angiography from the anterior position using a microcomputer system and floppy disc were compared to angiographic catheterization data obtained from the right anterior oblique position. This study demonstrated a good correlation with r = 0.91. To our knowledge, this is the first report of comparative first-pass left ventricular ejection fraction data and contrast angiography using a microcomputer system and a floppy disc.

Albumins

Endoscopic palliation of obstructive esophagogastric malignancy.

To investigate the efficacy of alternative endoscopic palliative therapies for obstructive esophagogastric malignancy, the experience of 53 patients treated between 1979 and 1986 was analyzed. Forty-seven patients had placement of intraesophageal prostheses. Ten patients had prostheses placed after neodymium:YAG laser therapy. In four of these patients, prosthesis placement was planned as part of the initial therapy. Twelve patients initially received laser therapy. In six, recurrent tumor was treated with intraesophageal prostheses 3 to 24 weeks after laser treatment. Comparing neodymium:YAG laser therapy to placement of the prosthesis, both techniques provided similar improvement in dysphagia. Patients receiving prostheses required less additional treatment for dysphagia. Life table analysis comparing survival rates from diagnosis to death showed no difference. The palliation provided by prostheses and neodymium:YAG laser appears to be quite similar; however, the prosthesis seems to be more lasting and require fewer resources.

Adenocarcinoma

Protection against hemolysis in ABO mismatched renal transplantation.

The kidneys from a blood group O cadaver donor were transplanted into two patients whose blood groups were B and A2B. The former developed a positive direct antiglobulin test (DAT) and hemolysis due to anti-B; the latter also developed a positive DAT, but due to anti-A. However, this second patient, unlike the first, did not have any hemolysis. Both patients were on the same immunosuppression regimen with cyclosporine. The possible protective roles of patients' ABO subgroup and blood group substances in plasma are discussed.

ABO Blood-Group System