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D O Rodgerson

Publications and source records attributed to D O Rodgerson.

At least 37 records · Page 2Linked to original sources
PubMed1989

Measurement of cyclosporine in plasma from patients with various transplants: HPLC radioimmunoassay with a specific monoclonal antibody compared.

This study compares cyclosporin A (CsA) concentrations in plasma from patients receiving various transplants, as measured by HPLC and RIA with a monoclonal antibody for CsA and an 125I-labeled ligand. The RIA was restandardized with in-house standards because it overestimated CsA by an average of 23%. The RIA was sensitive to 2 micrograms/L, the standard curve was linear from 20 to 500 micrograms of CsA per liter, analytical recovery was 98%, and CVs were less than 8% for intra- and interassay precision. RIA (y) vs HPLC (x) for 283 plasma samples from 145 patients gave a slope = 1.1256, r = 0.979. When the results were segregated according to transplant type, CsA in liver and heart recipients was overestimated by RIA as compared with HPLC: slope = 1.202, r = 0.973 and slope = 1.1477, r = 0.983, respectively. Adult and pediatric CsA values were acceptable when RIA and HPLC were compared: slope = 1.0755, r = 0.977 and slope = 1.0563, r = 0.980, respectively. For six samples (four heart, two liver recipients) where HPLC and RIA values demonstrated wide discrepancies, repeat HPLC and analysis of eluate fractions gave CsA concentrations nearer values by the initial HPLC assay. We conclude that this RIA cannot be substituted for HPLC in the case of heart and liver recipients. The need for each laboratory to standardize the RIA is obvious.

Adult↗
PubMed1988

Standardization for four protein analytes with the Behring Nephelometer.

Owing to the generally higher values observed in the initial establishment of immunoglobulins (Ig) G, A, and M assays with the Behring Nephelometer, we elected to verify five commercial protein calibrators. This initial verification was performed by standardizing the Behring Nephelometer with the World Health Organization (WHO) International Reference Preparation for Human Serum Immunoglobulins G, A, and M. The instrument was also standardized for immunoglobulins and transferrin with use of the Reference Preparation for Serum Proteins (RPSP II). Analytical recoveries of the commercial calibrators varied. Also, assigned protein concentrations in both the WHO and RPSP II preparations made them unacceptable to us as benchmark calibrators for the Behring Nephelometer. Individual proteins (IgG, IgA, IgM, and transferrin) were obtained and primary standards prepared. Both transferrin and IgG were successfully standardized. However, IgA and IgM primary standards lacked 100% antigenicity, requiring removal of nonreactive IgA and IgM or reassignment of the correct value. The problem remains to find appropriate purified materials for IgA and IgM standardization.

Blood Proteins↗
PubMed1987

Influence of specimen treatment on nonreactive HTLV-III sera.

We investigated effects of specimen treatment on HTLV-III antibody assay results. Freezing and thawing specimens 10 times did not increase specimen mean absorbance (A) values measured by the Abbott immunoenzymometric assay (IEMA). Heating blood donor serum specimens at 56 degrees C for at least 10 min inactivates virus, but converted 7.1% of nonreactive specimens to positive when measured by this IEMA. Also heating at 56 degrees C for 30 min increased A values of most specimens; however, the conversion to positive within assay ranged from 0 to 75%, with a mean of 17%. When 56 nonreactive patient specimens were heated, 55% became Abbott IEMA reactive, although ENI IEMA values did not increase and Western blot results remained nonreactive. Binding of immunoglobulins G and A to Abbott IEMA beads did not cause this conversion after heat treatment. We postulate that heating specimens causes alteration of some serum matrices and introduces nonspecific binding to assay bead antigen or antibody reagents. We recommend that for the Abbott IEMA, specimens may be stored frozen, and must not be heated to avoid altered reactivity.

Antibodies, Viral↗
PubMed1987

Presence of HTLV-III antibodies in immune serum globulin preparations.

The authors tested 15 immune serum globulin pharmaceutical preparations for antibody reactivity to human T cell lymphotrophic virus type III (HTLV-III) by the Abbott immunoenzymometric assay (IEMA). Although no evidence of HTLV-III infectivity has appeared after injection of similar preparations into humans, the authors found all samples IEMA reactive. Upon dilution, the authors demonstrated parallel decreases of antibody reactivity among two samples of gamma globulin, the Abbott-positive control, and a markedly reactive patient specimen. Gamma globulin isolated from sera of six animal species was nonreactive in the Abbott assay. All samples were nonreactive with the H-9 cell line antigen. Antibody reactivity to HTLV-III was confirmed in 13 of 15 gamma globulin samples when tested by the Electro-Nucleonics IEMA, and 14 samples contained at least the p24 band on Western blot analysis. Although false positivity occurs in IEMA assays possibly because of elevated protein concentrations and nonspecific binding, the authors, results show that in most circumstances immune serum globulin preparations tested do contain true reactivity to HTLV-III.

Antibodies, Viral↗
PubMed1986

Prevalence of antibodies to HTLV-III in quality-assurance sera.

We tested 146 clinical-laboratory quality-assurance sera for antibodies to human T-lymphotropic virus III (HTLV-III). Of 127 human-based samples, 39 (31%) were positive by an immunoenzymometric assay (IEMA). Samples of human origin that gave IEMA reactivity included four of 10 ethylene glycol-based (liquid) samples, two of six in-house pools of fresh sera, and 32 of 111 lyophilized samples. All 19 bovine-based samples were negative. Antibodies to HTLV-III in 16 samples were remeasured by a second IEMA and the Western blot technique. All assays detected antibody reactivity in four of the 16 samples; however, results of the second IEMA and the Western blot agreed best. We report large discrepancies between assay results when laboratory reagents are tested for HTLV-III antibodies, and find that many quality-assurance samples containing human sera have measurable IEMA reactivity for HTLV-III antibody. Reactivity in these assays indicates the presence of antibody, not viral infectivity.

Animals↗
PubMed1986

Triclonal gammopathy in a patient with plasma cell dyscrasia.

A triclonal gammopathy is an immunoglobulin abnormality in which three discrete monoclonal subpopulations of immunoglobulin molecules are present in a patient's serum. Monoclonal and biclonal gammopathies have been studied extensively, but relatively little is known about the much rarer triclonal gammopathies. The case described below illustrates some of the difficulties that this condition can present to the clinician and the clinical laboratory.

Humans↗
PubMed1985

Effect of arylsulfatase A and sialidase on the biochemical and immunological properties of creatine kinase isoenzyme BB.

This work describes the action of the lysosomal enzymes arylsulfatase A (EC 3.1.6.1) and sialidase (EC 3.2.1.18) on human creatine kinase (CK, EC 2.7.3.2) isoenzyme BB. The isoenzyme, which gives a positive reaction with the periodic acid-Schiff reagent, contains 12 molecules of sulfate and two molecules of sialic acid per molecule. On treatment with arylsulfatase, CK-BB lost enzyme activity but retained immunoreactivity, its isoelectric point was altered, and it was partly bound to a "Glyco-gel" affinity column. On treatment with sialidase, the isoenzyme lost activity, its immunoreactivity was decreased by 70%, and the inactivated CK-BB would not bind to either "Glyco-gel" or concanavalin A. We propose that the sulfate groups are involved in maintaining the integrity of the active site of the enzyme but are not involved in antigenic recognition sites on the molecule. Sialic acid plays an important role in both the structural pattern of the antigenic determinant and the active site of CK-BB.

Brain↗
PubMed1985

Thyrotropin as measured by a sensitive immunoradiometric assay.

An immunoradiometric assay (Boots-Celltech's "Sucrosep"; IRMA) for thyrotropin (TSH) was evaluated and results were compared with those of our in-house RIA procedure. The IRMA had a sensitivity of 0.02 milli-int. unit/L. In addition it displayed excellent intra- and inter-batch precision, cross-reacted negligibly with other pituitary hormones, and appeared to be relatively free of matrix effects (although deionized water did give an apparent TSH concentration of 0.13 milli-int. unit/L). Over the range 1.2 to 64 milli-int. units/L, correlation between the IRMA (y) and RIA (x) was excellent: y = 1.16x - 1.69 (r = 0.98). The normal reference interval for the IRMA was 0.4 to 4.2 milli-int. units/L. For patients suspected of hyperthyroidism who had been subjected to the thyroliberin test, the IRMA more effectively differentiated between euthyroidism and hyperthyroidism. During testing with thyroliberin, all nonresponding hyperthyroid patients had initial baseline TSH concentrations of less than 0.02 milli-int. unit/L by IRMA. This sensitive assay represents an important advance in the ability to differentiate between euthyroidism and hyperthyroidism.

Humans↗
PubMed1984

The purification of human creatine kinase BB with high specific activity.

This paper describes the purification of human creatine kinase BB with high specific activity (1,122 U/mg). The procedure used resulted in a protein yield of 5.4 mg (21% recovery) from 150 g of brain tissue. Two-dimensional electrophoresis and PAGE studies indicated that purified CK-BB might exist as native isoenzyme along with structural aggregates since the multi-banded appearance was reduced to a single band with sodium dodecyl sulfate treatment but not with 2-mercaptoethanol. Investigators are cautioned not to store brain tissue for prolonged periods of time before isolation of the isoenzyme as this may lead to protein redistribution with additional bands becoming evident on PAGE.

Brain↗
PubMed1984

The elucidation of adrenal-cortical status by measuring two-hour urinary-free cortisol levels.

Urinary-free cortisol (UFC) measured in 24-h samples has provided unambiguous data regarding adrenal-cortical status, but collection is cumbersome and compliance is a problem. We reasoned that measuring UFC in 2-h samples collected at strategic times would distinguish patients with adrenal-cortical disorders from normal subjects. Patients with Cushing's syndrome demonstrated late P.M. (samples collected between 2000 and 2400 h) 2-h UFC levels that were greater than or equal to 12.0 micrograms/2 h (reference interval for this time period is 0.1-3.2 micrograms/2 h, n = 35). Several patients with various symptoms of Cushing's syndrome displayed late P.M. levels within the reference interval. Those with adrenal insufficiency had morning (collected between 0500 and 0900 h) levels less than or equal to 0.2 microgram/2 h (reference interval 1.7-21.2 micrograms/2 h, n = 37). These data indicate that adrenal-cortical status is reflected by measuring UFC levels in 2-h samples.

Adrenal Cortex Function Tests↗
PubMed1981

A multilaboratory-evaluated reference method for the determination of serum sodium.

We carried out a statistically designed, multilaboratory study to evaluate a flame atomic emission spectroscopic (FAES) method for serum sodium as a Reference Method. definitive values for the serum pools for the study, with sodium in the 110-160 mmol/L range, were determined at the National Bureau of Standards by an ion-exchange/gravimetry method. The multilaboratory FAES results were judged against the preselected performance criteria for the Reference Method: maximum imprecision 1.5 mmol/L, maximum bias 2.0 mmol/L. The standard error of a single laboratory's performance of the method varied with concentration from 0.46 to 0.86 mmol/L with a maximum bias of 1.0 mmol/L; thus, the criteria were satisfied. The cooperating laboratories performed the method with either manual or semi-automated pipetting. Although both modes of pipetting satisfied our acceptability criteria, only the method with semi-automated pipetting is described here as the Reference Method. The statistical results indicate that the precision criterion can be fulfilled with fewer than four replicate analyses.

Humans↗