Publications by authors named "Gadsden R"

Sterile whole human blood control materials were commercially prepared in batches containing anticoagulants and preservatives and approximately 90, 150, and 230 mg/dL ethanol with and without 0.3% (w/v) sodium azide. Aliquots in sealed vials were stored by the manufacturer at 2-8 degrees C until shipped monthly to three academic toxicology laboratories that analyzed them in duplicate by gas chromatographic headspace methods at monthly intervals for one year.

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Combinations of certain phospholipids and gangliosides increase the specific activity of m calpain and can activate m calpain at 1 to 10 microM Ca2+ concentration. However, this level of calcium is still greater than the normal intracellular calcium level. We have used combinations of lipids to demonstrate the m calpain activity at the physiological Ca2+ level.

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The purpose of this study was to evaluate immunoassay methods for the measurement of serum cardiac creatine kinase isoenzyme (CK-MB) with respect to sensitivity and specificity. The CK-MB electrophoretic assay (Helena Laboratories) was used as the reference. Two principles of immunoassay were included in the evaluation,--immunoinhibition and solid phase separation.

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Proton nuclear magnetic resonance spectroscopy (1H MRS) has been used to identify ethanol in vivo and to detect other exogenous low molecular weight volatiles in human serum. 1H MRS was used to detect and quantitate 15 human sera containing various concentrations and combinations of ethanol, isopropanol, acetone, and methanol as previously quantitated by headspace gas chromatography. The 1H MRS method was linear for each alcohol.

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A precise, accurate, and nondestructive method for the detection and quantitation of serum ethanol in humans using proton (1H) nuclear magnetic resonance spectroscopy (MRS) was developed. The 1H MRS method was linear within the range of 30-1500 mg/L. The lowest detectable ethanol concentration was 15 mg/L, with 30 mg/L being the lowest level reproducibly quantitated.

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Irradiation of stored red blood cells (RBC) is increasingly utilized for patients who are immunosuppressed or on chemotherapeutic regimens. With the growing demand for irradiated cellular blood products, there has been an increasing need for transfusion services to store previously irradiated blood until needed for transfusion. The effect of irradiation on aging stored RBC has not been studied to date.

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A prospective clinical evaluation is reported for analysis of maternal serum alpha fetoprotein (s.AFP) testing by recently developed enzymeimmunoassay automated systems. The reference method for the study was a manual competitive binding radioimmunoassay which has been utilized by us in the Maternal Serum AFP Screening Program at the Medical University of South Carolina for the past five years.

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Serum alpha-fetoprotein (s.AFP) has been established as a useful tool in monitoring of high-risk pregnancies, as an indicator of fetal neural tube defects, and has been used as an adjunct tumor marker and for monitoring therapeutic efficacy in the treatment of certain tumors. To date, the methods for measuring s.

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Red blood cells (pRBC) collected in citrate, phosphate, dextrose, adenine-formula 1 (CPDA-1) and citrate, phosphate, dextrose-adenine, manitol saline solution (CPD-ADSOL [AS-1]) anticoagulants are increasingly being stored for variable periods in transfusion service inventories following irradiation. While anecdotal reports of increased K+ following irradiation and storage have recently appeared in the literature, concomitant in vitro biochemical changes resulting from differences in anticoagulants have not been reported. Utilizing two venipunctures, two units each of 225 mL of blood from five volunteers were collected in anticoagulant-adjusted CPDA-1 and AS-1 bags.

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Spironolactone and one of its metabolites, canrenone, cross-react with some digoxin immunoassays to result in erroneous serum digoxin concentrations. Recently, additional compounds, 7-alpha-thiomethylspirolactone (7-a-TMS) and 6-beta-hydroxy-7-alpha-thiomethylspirolactone (6-B-OH-7-a-TMS), have been reported to be quantitatively important metabolites of spironolactone. This study was initiated to evaluate the cross-reactivity of these metabolites, canrenone, and spironolactone with four different digoxin immunoassays.

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The appropriateness of serum digoxin concentration (SDC) orders was evaluated with respect to indication for use, sampling time, and action taken by physicians when the reported SDC was out of the normal therapeutic range; the effect of the two data-collection methods used (retrospective and concurrent audits) on the results was studied. Criteria for the appropriate use of SDCs were approved by the medical staff through the pharmacy and therapeutics committee. Patients on adult medicine services were entered into the study as daily SDC determinations were reported by the clinical laboratory.

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We have characterized and identified uric acid as an interferent to peroxidase catalyzed reactions where hydrogen peroxide is generated at relatively low concentrations. The implications of these findings are important for those utilizing peroxidase as an indicator reaction where low primary substrate concentrations require their preliminary extraction or chemical modification. We have shown that the elimination of uric acid as an interferent from biologic fluid obviates the necessity for such treatment.

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The purpose of this study was to determine if serum digoxin concentration data using three different automated immunoassay methods would produce similar pharmacokinetic values in normal volunteer subjects. Area under the curve (AUC), steady-state volume of distribution/bioavailability ratio (Vd/F), terminal elimination rate constant (beta), clearance/bioavailability ratio (CL/F), maximum digoxin concentration (Cmax), minimum digoxin concentration (Cmin), and time of peak (Tp) were evaluated. Ten healthy volunteers received digoxin capsules 0.

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We describe a method for analyzing the choline-containing phospholipids, namely phosphatidylcholine, lysophosphatidylcholine, and sphingomyelin that is highly sensitive, easy to perform, and very reliable. The method employs enzymic hydrolysis of choline from these phospholipids by phospholipase D with subsequent oxidation of choline by choline oxidase and generation of hydrogen peroxide. Hydrogen peroxide is then reduced by peroxidase with p-hydroxy-phenylacetic acid acting as an oxygen acceptor to form a fluorescent product which is stable for at least 24 h without loss of linearity.

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Running is associated with an increase in plasma concentrations of certain anterior pituitary hormones and adrenal steroids. This study reports such increases after a marathon race. Six trained female runners, 26 to 42 years old, participated in a marathon race.

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The effect of renal function and digoxin use in adult patients on interference from digoxin-like immunoreactive substances (DLIS) with three digoxin immunoassays was studied. Hospital patients entered into the study were categorized into the following groups according to renal function: group I (serum creatinine less than 1.5 mg/dL), group II (serum creatinine 1.

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The enzymatic alcohol (ethanol, ALC) analytical pack for the duPont aca is intended primarily for the analysis of serum or plasma samples containing no visibly detectable free hemoglobin (non-hemolyzed samples). It has become apparent, through clinical and medicolegal consultation, that this methodology has been applied for assay of ethanol content in hemolyzed samples (sample sources: clinical and forensic cases). The influence of sample free hemoglobin on the ace ethanol method was investigated.

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The timely availability and presentation of critical and interesting patient data is essential to ensure quality patient care as well as ease of recognition and, secondarily, to provide material for teaching and research. The ability to accomplish these goals expeditiously in a complex and busy clinical laboratory may be difficult to acquire. An on-line, computerized system has been developed which automatically searches each patient record for up to 600 different laboratory tests, compares each result against individually established limits, and then formats pertinent test results for maximum discrimination.

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Following spinal cord injury in rats there was a time-dependent change of vascular permeability as reflected by extravasation of 125I-labelled serum albumin. The change of vascular permeability correlated with tissue calcium and water accumulation suggesting that cord exposure to plasma calcium as a consequence of vascular injury may contribute to the progressive post-traumatic cord necrosis.

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The authors prospectively performed simultaneous determinations of serum delta osmolality (delta-Osm), enzymic (alcohol dehydrogenase [ADH]) quantitation of serum ethanol (EtOH), and urine drug screens on 339 acutely intoxicated patients. In addition, the authors established reference ranges for measured and calculated serum osmolalities in a group of 55 healthy volunteers. The authors determined the clinical utility of the combined delta-Osm/ADH procedure for detecting the presence of EtOH or other low molecular weight (Mr) volatiles.

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Prostatic carcinoma is a significant cause of male cancer death. The majority of cases present as incurable disease. The measurement of acid phosphatase has served to confirm clinically suspected disease and staging.

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We have developed a rapid extraction process using the DuPont Prep I automated extractor/concentrator to prepare serum samples for the high-performance liquid chromatographic (HPLC) determination of clonazepam. The drug, at an alkaline pH, is applied to a styrene divinylbenzene preparatory extraction column. The Prep I is a reversible centrifuge that allows the sample to pass through the preparatory column, followed by a wash solution of deionized water.

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Parenteral calcium may augment the degree of calcification within brains of human neonates (p less than 0.01). This observation is supported by histochemistry, atomic absorption of ashed brain, selected area diffraction, and energy dispersive microanalysis.

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A new enzyme linked immunosorbent assay (ELISA) kit which utilizes a monoclonal antibody against prostatic acid phosphatase (PAP) was compared with current radioimmunoassay (RIA) methodology which uses a polyclonal antibody. Both assays are double antibody immunoassays with the major difference being the method of antibody preparation. A study of intrarun precision using control material showed an average within run coefficient of variation (CV) percent as 7.

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