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B Edwards

Publications and source records attributed to B Edwards.

At least 73 records · Page 4Linked to original sources
PubMed1991

Quantitation of hepatitis B surface antibody by an automated microparticle enzyme immunoassay.

A fully automated microparticle enzyme immunoassay, IMx AUSAB, was developed for the detection and quantitation of antibody against hepatitis B surface antigen (anti-HBs). The IMx AUSAB assay can complete 24 tests in less than 45 minutes. Anti-HBs concentrations in specimens are calculated automatically by comparison of the specimen rate to values determined from a stored standard curve. IMx AUSAB sensitivity is 2-3 mIU/ml, equivalent in sensitivity to AUSAB RIA or EIA. Specimens from blood donors, diagnostic and hospital patients, hepatitis B vaccinees, and individuals with a variety of infectious and autoimmune diseases tested in parallel by IMx AUSAB and AUSAB RIA or IMx AUSAB and EIA gave overall qualitative agreement of 97.8% (1265/1293) and 99.1% (1281/1293), respectively. The prevalence of anti-HBs ranged from 5.9% in volunteer blood donors to 47.0% of specimens from a sexually transmitted disease clinic. Most discordant specimens (18/34) were low level reactive (less than 10 mIU/ml) by AUSAB RIA, but negative by IMx AUSAB and AUSAB EIA. These specimens were also negative for antibodies to hepatitis B core antigen (anti-HBc). Six discordants were low level reactive by IMx but negative by RIA and EIA. Three of these six specimens were also reactive for anti-HBc suggesting that the IMx AUSAB reactivity resulted from the presence of low level anti-HBs. Quantitative agreement between IMx AUSAB and RIA or IMx and EIA for 106 specimens ranging in anti-HBs concentration from 1 to 30,000 mIU/ml gave linear correlation coefficients of 0.91 and 0.96, respectively. The IMx test was useful for monitoring hepatitis B vaccine response and seroconversion levels after hepatitis B infection.

Automation↗
PubMed1990

Isotretinoin-basal cell carcinoma prevention trial. Design, recruitment results, and baseline characteristics of the trial participants. The ISO-BCC Study Group.

The Isotretinoin-Basal Cell Carcinoma Prevention Trial (ISO-BCC Study) is a double-masked, randomized, placebo controlled, multicenter clinical trial. It is the first intramural cancer chemoprevention trial sponsored by the Division of Cancer Prevention and Control of the National Cancer Institute. This trial was designed to evaluate the effectiveness of chronic administration of low dosage levels (10 mg) of a synthetic retinoid, isotretinoin, in reducing the incidence of basal cell carcinoma in a high-risk population and to determine the incidence and severity of side effects associated with this long-term treatment. Between 1984 and 1987, eight clinical centers enrolled 981 participants between the ages of 40 and 75, who had two or more biopsy proven basal cell carcinomas in the 5 years before trial entry. This article describes the trial design, recruitment results, and baseline characteristics of the participant population in the ISO-BCC Study.

Adult↗
PubMed1990

Turning danger into opportunity.

Brian Edwards looks at the management of change required to pave the way for successful implementation of the white paper, and sees a challenging time ahead.

Administrative Personnel↗
PubMed1990

Rapid and sensitive detection of DNA in Southern blots with chemiluminescence.

A new chemiluminescent Southern blot procedure offers molecular biologists a safe, ultrasensitive and rapid alternative to conventional 32P-based systems. This new DNA detection system, SOUTHERN-LIGHT, has been developed by Tropix, Inc. The luminescent signal is produced from a direct chemiluminescent substrate, disodium 3-(4-methoxyspiro[1,2-dioxetane-3-2'-tricyclo-[3.3.1.1 .3,7]decan]-4-yl) phenyl phosphate (AMPPD), which decomposes upon dephosphorylation with alkaline phosphatase. SOUTHERN-LIGHT is an ultrasensitive, rapid detection kit for use with membrane-bound DNA. It is the first test kit to incorporate AMPPD. It requires no specialized equipment and results can be conveniently imaged on instant film or x-ray film within 5-60 min of exposure.

Adamantane↗
PubMed1989

1,2-dioxetanes: novel chemiluminescent enzyme substrates. Applications to immunoassays.

We have synthesized and studied two 1,2-dioxetane-based chemiluminescent enzyme substrates: 3-(2'-spiroadamantane)-4-methoxy-4-(3"-phosphoryloxy)phenyl- 1,2-dioxetane (AMPPD), and, 3-(2'-spiroadamantane)-4-methoxy-4-(3"-beta-D'-galactopyrano -yloxy)phenyl-1,2- dioxetane (AMPGD), which can be activated to chemiluminescence at 470 nm by alkaline phosphatase and beta-D-galactosidase, respectively. In addition, we observed that certain macromolecules enhance the luminescence of AMPPD. For example, the addition of 0.1% bovine serum albumin amplifies the luminescent signal and improves the detection limit for alkaline phosphatase by approximately one order of magnitude under certain conditions. This effect is due to the presence of a hydrophobic microenvironment provided by the enhancer which 'stabilizes' the dephosphorylated AMPPD emitter. Alkaline phosphatase catalysed chemiluminescence from AMPPD is constant for a prolonged period of time. Using AMPPD we were able to detect 0.01 attomole quantities of alkaline phosphatase immobilized on membrane supports and imaged on photographic film and, in solution, measured in a luminometer. AMPPD and AMPGD offer alternatives to colorimetric and fluorescent substrates for alkaline phosphatase and beta-D-galactosidase labels used in enzyme immunoassays. The simplicity and sensitivity of this chemiluminescent readout allowed the development of rapid clinical assays (e.g. beta-hCG, LH, TSH and others).

Alkaline Phosphatase↗
PubMed1989

Cobalt, chromium, and nickel concentrations in body fluids of patients with porous-coated knee or hip prostheses.

Co, Cr, and Ni concentrations were determined by electrothermal atomic absorption spectrophotometry in serum and urine specimens collected from a group of 28 patients at intervals of from 1 day to 2.5 years after total knee or hip arthroplasty with porous-coated prostheses fabricated of Co-Cr alloy (ASTM F-75-82). Two control groups were also tested: (a) 42 healthy adults and (b) 16 orthopaedic patients after total knee or hip arthroplasty with porous-coated prostheses fabricated predominantly of Ti-Al-V alloy (ASTM F-136-84). All prostheses contained polyethylene components to avoid metal-to-metal contact. Mean Co concentrations in serum and urine were slightly increased in patients with Co-Cr knee implants at 6-120 weeks after surgery, compared with (a) preoperative values, (b) corresponding values in patients with Co-Cr hip implants, and (c) corresponding values in control patients with Ti-Al-V knee and hip prostheses. Substantially increased Co levels were observed in serum and urine of two patients at 7 weeks and 22 months postarthroplasty, associated with loosening of the prostheses; one of the patients also had elevated Cr levels in serum and urine. Although ASTM F-75-82 and F-136-84 alloys contain very little Ni (less than 1.0 and less than 0.2% Ni, respectively, by wt), mean Ni concentrations in serum and urine were greatly increased at 1-2 days after implantation of Ti-Al-V and Co-Cr prostheses, diminishing by 2 weeks. The postoperative hypernickelemia and nickeluresis may reflect contamination of the operative field with Ni-containing particles from the drills, cutting jigs, and drilling jigs, or it may represent a previously unrecognized pathophysiological response to surgery.

Adult↗
PubMed1989

A comparison of chemiluminescent and colorimetric substrates in a hepatitis B virus DNA hybridization assay.

We compared the sensitivity of a chemiluminescent substrate 3-(2'-spiroadamantane)-4-methoxy-4-(3"-phosphoryloxy)phenyl- 1,2-dioxetane (AMPPD) and a chromogenic substrate 5-bromo-4-chloro-3-indolyl phosphate/nitroblue tetrazolium (BCIP/NBT) for detection of an alkaline phosphatase label in a hepatitis B virus "core antigen" DNA (HBVc) probe hybridization assay. Chemiluminescent signal obtained from AMPPD hydrolysis by alkaline phosphatase was detected with Polaroid Instant Black and White Type 612 film. The chemiluminescent assay detected 1.18 x 10(6) copies of HBVc plasmid DNA in 30 min. By comparison, 9.8 x 10(7) copies of DNA could be measured using chromogenic BCIP/NBT substrate within the same incubation time. After further development, the chemiluminescent endpoint permitted detection of 4.39 x 10(4) copies of HBVc plasmid DNA in 2 h.

Adamantane↗
PubMed1989

Second generation assays for the detection of antibody to HBsAg using recombinant DNA-derived HBsAg.

A second generation radioimmunoassay (RIA) and enzyme-linked immunoassay (EIA) for the detection and quantitation of the antibody to hepatitis B surface antigen (anti-HBs) was developed which utilizes recombinant DNA-derived HBsAg (rHBsAg) in place of human plasma derived HBsAg. In these sandwich assays, rHBsAg immobilized on a solid phase was used to capture anti-HBs from the specimen and rHBsAg conjugated to horseradish peroxidase or radiolabeled with 125I was used as a detecting reagent. These rHBsAg-based assays were compared to a commercial radioimmunoassay for anti-HBs detection (AUSAB RIA). For a population of 1711 sera and plasma specimens, 99.2% overall agreement was demonstrated between the recombinant RIA and EIA and 98.6% agreement was observed between the recombinant assays and AUSAB-RIA. The recombinant assays demonstrated equivalent sensitivity and detectability to AUSAB RIA. Most discrepant samples were low-level reactive by AUSAB-RIA, generally less than 10 mIU/ml, and likely represent nonspecific reactivity since no other marker for hepatitis B infection was detected in these samples.

Autoimmune Diseases↗
PubMed1989

Patellar fractures. A 30-year follow-up.

Forty patients who had had a patellar fracture during the years 1950-58 were reevaluated 30 years later. A clinical and radiographic examination was performed. Fourteen patients had subjective complaints. Two thirds of the patients who had more than 2-mm diastasis or 1-mm incongruity had complaints and reduced quadriceps strength. Radiographically, all the patients had a reduction in the lateral patellofemoral distance in the axial view with the greatest reduction in the knees with diastasis or incongruity of the fracture.

Adult↗
PubMed1989

Chemiluminescent enzyme immunoassay of alpha-fetoprotein based on an adamantyl dioxetane phenyl phosphate substrate.

We have evaluated a new chemiluminescent substrate for the alkaline phosphatase (EC 3.1.3.1) label used in a Hybritech Tandem-E immunoassay of alpha-fetoprotein (AFP). The new substrate, adamantyl 1,2-dioxetane phenyl phosphate (AMPPD), emits light at 477 nm when acted upon by the enzyme. Detection limits for AFP with this method were 33 ng/L (mean of 20 replicates of the zero standard + 2 SD) and 470 ng/L (twice background). Between-batch CVs ranged from 4.31% to 9.60% for AFP in the range 29.1-132.0 micrograms/L. Comparison of results for 49 specimens assayed with use of the chemiluminescent kit and a colorimetric version of the AFP assay gave statistical values as follows: slope = 0.88, intercept = 4.19, and r = 0.94.

Adamantane↗
PubMed1989

Reported illness and compliance in US travelers attending an immunization facility.

Two hundred fourteen international travelers were retrospectively interviewed by telephone. The incidence of diarrhea was found to be highest in East Africa (44%) and Southeast Asia (42%). Other reported illnesses were rare, the highest incidence occurring in China with four upper respiratory tract infections reported among ten travelers. Antimalarial compliance was assessed and found to be age-related, with noncompliance reported in 41% of patients younger than 40 years and in only 19% of patients older than 40 years. Eight of 35 women who were receiving chloroquine phosphate reported menstrual irregularities. Further investigation of this possible association is underway. We continue to stress compliance with antimalarial medication.

Adolescent↗
PubMed1988

Platelet aggregation is inhibited by long chain acyl-CoA.

Oleoyl coenzyme A and other acyl-CoA derivatives inhibited ADP or thrombin-induced aggregation of platelets. Arachidonic acid-induced aggregation was also inhibited, but not the slower aggregation caused by 1-oleoyl-2-acetylglycerol or tetradecanoyl-phorbol-13-acetate. Coenzyme A and free fatty acids had little or no effect, and transfer of labeled oleate from oleoyl Co-A to other lipid classes was not detected. Because acyl Co-A compounds have recently been shown to modulate protein kinase C activity, acyl Co-A may provide a useful tool for investigating activation sequences in platelets and other membranes.

Acyl Coenzyme A↗
PubMed1987

In vitro activity of BMY 28100, a new oral cephalosporin.

BMY 28100, a new oral cephalosporin, demonstrated good in vitro activity against common gram-positive and gram-negative respiratory and urinary tract pathogens. Its activity was shown by microdilution techniques to be generally higher than those of ampicillin, cephalothin and cephalexin, but comparable to those of cefaclor and, except for Haemophilus spp. and Branhamella spp., to amoxicillin/clavulanate.

Bacteria↗
PubMed1987

Skeletal localization of samarium-153 chelates: potential therapeutic bone agents.

A series of stable complexes of 153Sm has been produced using multidentate acetate and phosphonate ligands. Biodistribution studies in unanesthetized rats showed varying degrees of bone and soft-tissue uptake for these complexes. Of the complexes studied, [153Sm] ethylenediaminetetramethylenephosphonate (EDTMP) showed the best combination of high bone uptake, low nonosseous uptake, and rapid blood clearance which warranted its further investigation in rabbits. Rabbit studies confirmed the [153Sm]EDTMP results obtained in rats. Blood clearance in rabbits was found to be more rapid than [99mTc] methylene diphosphonate (MDP). Scintigraphic images were virtually indistinguishable from [99mTc]MDP images. Lesion/normal bone ratios were determined from digitized images obtained using a drill hole model and found to be approximately 17:1. Based on these excellent biodistribution characteristics, [153Sm] EDTMP could be therapeutically useful in treating metastatic bone cancer.

Animals↗
PubMed1986

153Sm radiotherapeutic bone agents.

Samarium-153 is a radionuclide which can be produced in high yield by neutron irradiation and which has nuclear properties that make it attractive for use as a radiotherapeutic agent. Several phosphonate complexes of 153Sm were synthesized and characterized by electrophoresis and HPLC. A procedure based on cation exchange chromatography was developed for measuring complex yields. The complexes could be produced in yields greater than 99%, were anionic, and most exhibited a single HPLC peak.

Acetates↗
PubMed1986

In vivo skeletal localization properties of 99mTc complexes of large phosphonate ligands.

Tetramethylenephosphonate derivatives of norborane (TPNB) and dicyclopentadiene (TPDCPD) were shown to readily form stable chelates with 99mTc that had high and selective bone uptake. The skeletal uptake and blood clearance properties of 99mTc-TPNB were similar to 99mTc-MDP in both rats and rabbits. This suggests additional studies to further evaluate 99mTc-TPNB or perhaps other large-organic based multidentate phosphonate ligands as potential bone imaging agents is warranted.

Animals↗