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Biomedical subjects

M B Simpson

Publications and source records attributed to M B Simpson.

At least 19 recordsLinked to original sources
PubMed1994

The effect of postoperative wound drainage reinfusion in reducing the need for blood transfusions in elective total joint arthroplasty: a prospective, randomized study.

A prospective, randomized study was conducted in 24 patients using the Solcotrans Orthopaedic Drainage Reinfusion System (Smith & Nephew Richards Inc, Memphis, Tenn) for postoperative blood salvage in total joint arthroplasty. The amount of postoperative autologous blood salvage averaged 946 mL. Only 25% of the study group required postoperative transfusions, compared to 83% of the control group (P = .016). In total knee arthroplasties, only 11% of the study group required transfusions, compared to 78% of the control group (P = .018). There were no transfusion reactions, infectious complications, or coagulopathies. Postoperative blood salvage is a safe, reliable, and effective source of autologous blood.

Adult↗
PubMed1992

The incidence of permanent upper and lower extremity profiles in active duty Army officers.

The records of 89,955 active duty Army officers were reviewed to determine their incidence of permanent upper and lower extremity profiles. Only 1,706 officers (1.897%) have permanent upper or lower extremity profiles. However, the incidence of such profiles varies with respect to rank, branch, and sex. Some officer groups have an incidence as high as 37%. Although the overall incidence of such profiles is quite low, the dramatically increased incidence in some officer groups demands scrutiny.

Cross-Sectional Studies↗
PubMed1992

Autologous transfusions for orthopaedic procedures at a children's hospital.

We conducted a critical review of the use of autologous transfusions in orthopaedics at a tertiary-care children's hospital. The cases of 198 children who deposited blood before an orthopaedic operation were analyzed. There were 175 children who were enrolled in the program of preoperative deposit of autologous blood who later needed transfusion of blood; 73 per cent of them received only autologous blood. Seventy patients also had intraoperative salvage. We were unable to document a proved benefit of intraoperative salvage of blood in this group of patients. Forty patients had some difficulty donating autologous blood preoperatively, but these problems were rarely serious. Major human errors occurred in thirteen patients and resulted in some patients receiving homologous transfusions while autologous blood components were still available. Fifty-five (40 per cent) of all of the transfusions were administered in clinical circumstances that failed to meet generally accepted criteria for transfusion, and fifty-four (38 per cent) of the postoperative transfusions also failed to meet these criteria. This was true of the homologous transfusions in the study as well. Although an autologous blood transfusion is a generally safe procedure, it is not without risk, and human errors can occur. In light of the potential complications, surgeons should adhere to the standard indications for transfusion when administering autologous blood.

Adolescent↗
PubMed1988

Long-term treatment of severe dysarthria: a case study.

This case study describes the long-term treatment and changing symptoms in a single subject with dysarthria secondary to basilar artery thrombosis. Initially, the subject was anarthric. Treatment efforts thereafter were directed toward modifying speech respiration, velopharyngeal function, articulatory precision, speech intensity, and speech intelligibility. A variety of treatment and measurement techniques are illustrated. The behavioral change resulting from each of the treatments was small. However, when combined, these small gains in conjunction with some neurological recovery resulted in significantly improved communication and quality of life for this subject. Implications for management of similar subjects are discussed.

Behavior Therapy↗
PubMed1985

Automatic identification of late potentials.

The purpose of the present study was to develop an algorithm for the automated identification of ventricular late potentials (LP) that can be recorded non-invasively by means of the signal averaging technique. This new algorithm was designed to determine the possible presence and the onset and duration of a given LP by analyzing the end of the QRS complex. As there is no objective standard for identifying these late potentials, the new algorithm was developed by continuous comparison and adaptation to visual analysis in 65 patients (algorithm definition phase). In the subsequent trial phase, visual and automated analysis were compared in a second cohort of 50 patients (40 patients with and 10 patients without late potentials). In the latter 50 patients, the results obtained with the new algorithm corresponded to the analysis made by at least two of three independent observers in 92% of cases. In only four patients--one without and three with late potentials--there was no agreement between the observers and the new program. In conclusion, the new algorithm can be used reliably for the evaluation of late potentials. The results are more objective. They are reproducible, which is of great advantage when data from different groups are to be compared or when less experienced investigators are using non-invasive methods for registration of late potentials.

Arrhythmias, Cardiac↗
PubMed1985

Lea blood group antigen on human platelets.

One- and two-stage radioligand assays were used to determine if human platelets possess the Lea antigen. Goat IgG anti-Lea antibody was purified by multiple adsorptions with Le(a-b-) human red blood cells, followed by affinity chromatography with synthetic Lea substance and labeling with 125I. Human IgG anti-Lea antibody was used either in a two stage radioassay with 125I-labeled mouse monoclonal IgG anti-human IgG as the second antibody or, alternatively, purified by Staph protein A chromatography, labeled with 125I, and used in a one-stage radioassay. Platelets from donors of appropriate red blood cell phenotypes were incubated with the antisera, centrifuged through phthalate esters, and assayed in a gamma scintillation counter. Dose response and saturation curve analysis demonstrate the presence of Lewis a antigen on platelets from Lea+ donors. Furthermore, platelets from an Le(a-b-) donor incubated in Le (a+b-) plasma adsorb Lea antigen in a similar manner to red blood cells. The clinical significance of these antigens in platelet transfusion remains undefined.

Blood Platelets↗
PubMed1985

Presence of P blood group antigens on human platelets.

Except for ABH antigens, the presence of red cell (RBC) antigens on human platelets has been a source of disagreement among investigators. Because ABH antigens share precursor sequences with P-system saccharides, the authors examined human platelets for evidence of P blood group antigens. Anti-P was directly labeled with 125I and incubated with normal platelets in a one-stage radioimmunoassay (RIA). Alternatively, platelets from donors of known RBC phenotype were incubated with anti-P, anti-P1, or anti-Tja, washed, incubated with FITC-labeled goat anti-human immunoglobulin and evaluated by fluorescence flow cytometry. The results of these assays demonstrate that platelets express P blood group antigens in parallel to the donor's RBCs. The role of these antigens in platelet transfusion is not known.

Blood Group Antigens↗
PubMed1985

Heterogeneous distribution of antigens on human platelets demonstrated by fluorescence flow cytometry.

We have used fluorescence flow cytometry to analyse cell-to-cell variability in the density of platelet ABH, Ii, Lewis, P, P1A1, Bak,a and HLA class I antigens. Human IgG and IgM antibodies were used in a two-stage assay with goat FITC-conjugated antihuman IgG (H&L) antibody as the label, followed by single cell analysis of 10 000 platelets per sample using a 256-channel fluorescence flow cytometer (Becton-Dickinson FACS Analyser). Computer analysis of fluorescence intensity histograms for mean and peak channel and coefficient of variation shows that the degree of heterogeneity in platelet antigen density varies with each particular blood group. The broad fluorescence distribution curves with oligosaccharide antigens (CVs: A = 53, B = 40, I = 44, Lea = 40, P = 40) indicate that these antigens possess a greater variability in the number of sites per cell compared to the more homogeneous distribution of P1,A1 BaK,a and HLA (CVs: P1A1 = 24, HLA = 30). These findings may partly account for the mechanism by which transfusion of ABO-incompatible platelets results in a biphasic survival curve, with a period of early rapid removal of those platelets with a high density of antigen sites, followed by a relatively normal survival curve for those platelets that possess only a few or no antigen sites. In contrast, P1A1 and HLA sites are less variable in number from one platelet to another in a given donor, and immune-mediated removal would be more likely to approximate a single exponential curve.

Blood Group Antigens↗
PubMed1985

Absence of ABH antigens on neutrophils.

Many investigators have concluded that polymorphonuclear leucocytes (PMN) express ABH antigens in parallel to red cells (RBC). We have examined human PMN for ABH antigens using human isoantibodies and mouse monoclonal antibodies with three highly sensitive and specific two-stage assay systems: fluorescence flow cytometry, immunofluorescence microscopy, and avidin-biotin immunoperoxidase microscopy. In all three assays the ABH antigens could not be detected on the surface of PMN. Previous reports alleging that ABH antigens occur on PMN probably represent false positive reactions due to inherent technical problems.

ABO Blood-Group System↗
PubMed1985

The origin of ABH antigens on human platelets.

ABH antigens are present on platelets from individuals of the corresponding red cell phenotype, but the extent to which these antigens are intrinsic or adsorbed remains undefined. To evaluate platelets for intrinsic H substance, an IgM mouse monoclonal antibody against type 2H chain (the intrinsic H structure found on erythrocytes) was labeled with 125I and incubated with platelets from donors of different ABO type. The antibody showed dose-response saturation curves, and binding to platelets paralleled that of the red cell ABO type, with O greater than B greater than A1 greater than A1B greater Oh cells, giving a single factor variance F of 190 (P less than .0005). Passive adsorption of A antigens by platelets has been previously reported. To verify this phenomenon for A and B antigens and to quantitate the elution of A and B antigens from platelets, the following assay system was used. Platelets from group A1 and B donors were incubated in plasma from group O donors, and platelets from group O donors were incubated in plasma from different ABO, Lewis, and presumed secretor-type donors. Human IgG anti-A or anti-B was added to the platelets. The amount of antibody bound was determined with a 125I-labeled mouse monoclonal anti-human IgG. When incubated for 96 hours in group O plasma, group A1 platelets showed a 45% to 50% decrease in binding of anti-A. There was no significant change in the level of type 2H antigen on these platelets during the same incubation period. Group O platelets incubated in A or B plasmas rapidly acquired the antigens, but if returned to their original plasma, 95% of this passively adsorbed antigen eluted off within 18 hours. The maximum uptake of A and B substances was influenced by the Lewis and secretor type of donor plasma. Our present study demonstrates that ABH antigens on platelets consist of type 2H chains, which are presumably intrinsic as when found on red cells, and of passively adsorbed ABH structures, which are presumably type 1H chains.

ABO Blood-Group System↗
PubMed1984

The presence of the Ii blood group system on human platelets.

To examine platelets for the Ii antigens, high-titer human IgM anti-I and anti-i antibodies were affinity purified, radiolabeled with 125I, and incubated with adult and cord platelets. Saturation binding curves were performed by incubating adult platelets with serial dilutions of concentrated 125I-anti-I. Inhibition binding curves were performed by incubating adult platelets with doubling dilutions of concentrated unlabeled anti-I mixed with 125I-labeled anti-I. Adult platelets bound significantly more anti-I than anti-i, while cord platelets bound more anti-i than anti-I (P less than 0.025). Both anti-I and anti-i show a temperature-dependent dose-response curve of maximum binding at 4 degrees C. Binding of 125I-labeled anti-I was inhibited by preincubation with 100-fold concentration of unlabeled anti-I. The authors conclude that platelets express I/i antigens in parallel with that of red blood cells.

Adult↗
PubMed1984

Pelvic-femoral osteomyelitis complicating Crohn's disease.

Osteomyelitis of the pelvic bones arises in Crohn's disease when enteric fistulas from the ileocolonic region allow extention of the anaerobic intestinal flora to the psoas region of the right hemipelvis. Bone destruction is usually an unexpected finding during roentgenographic evaluation of abdominal symptoms in young men with severe ileocecal disease. Suppressive therapy and previous abdominal surgery do not appear to be significant predisposing factors. Therapy requires dé-bridement, resection/saucerization, drainage, and appropriate antibiotic coverage.

Adolescent↗
PubMed1978

Appearance of maternal anti-JK a antibody following intrauterine transfusions and amniocentesis.

A case is presented that suggests that intrauterine transfusion carries the risk of sensitization to red cell antigens other than Rho. In this case intrauterine transfusions of JK a-positive red cells were followed by the appearance in the mother's serum of anti-JK a, an antibody known to cause hemolytic disease of the newborn. The use of the mother as a donor of red cells for her fetus will circumvent the problem of further maternal sensitization.

Adult↗