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PubMed2000

Electromagnetic field strength levels surrounding electronic article surveillance (EAS) systems.

Electronic article surveillance (EAS) is used in many applications throughout the world to prevent theft. EAS systems produce electromagnetic (EM) energy around exits to create an EM interrogation zone through which protected items must pass before leaving the establishment. Specially designed EAS tags are attached to these items and must either be deactivated or removed prior to passing through the EAS EM interrogation zone to prevent the alarm from sounding. Recent reports in the scientific literature have noted the possibility that EM energy transmitted by EAS systems may interfere with the proper operation of sensitive electronic medical devices. The Food and Drug Administration has the regulatory responsibility to ensure the safety and effectiveness of medical devices. Because of the possibility of electromagnetic interference (EMI) between EAS systems and electronic medical devices, in situ measurements of the electric and magnetic fields were made around various types of EAS systems. Field strength levels were measured around four types of EAS systems: audio frequency magnetic, pulsed magnetic resonant, radio frequency, and microwave. Field strengths from these EAS systems varied with magnetic fields as high as 1073.6 Am(-1) (in close proximity to the audio frequency magnetic EAS system towers), and electric fields up to 23.8 Vm(-1) (in close proximity to the microwave EAS system towers). Medical devices are only required to withstand 3 Vm(-1) by the International Electrotechnical Commission's current medical device standards. The modulation scheme of the signal transmitted by some types of EAS systems (especially the pulsed magnetic resonant) has been shown to be more likely to cause EMI with electronic medical devices. This study complements other work in the field by attaching specific characteristics to EAS transmitted EM energy. The quantitative data could be used to relate medical device EMI with specific field strength levels and signal waveforms. This is one of several efforts being made by the FDA, the electronic medical device industry and the EAS industry to mitigate the potential for EMI between EAS and medical devices.

Electromagnetic Fields↗

PubMed1997

Multicenter evaluation of the flow cytometry T-cell crossmatch: results from the American Society of Histocompatibility and Immunogenetics-College of American Pathologists proficiency testing program.

BACKGROUND: The performance characteristics and interlaboratory comparisons of the T-cell flow cytometry crossmatch remain largely unknown. METHODS: This study was performed using data from the ASHI-CAP proficiency testing program. Four unknown sera and two unknown cells were sent to participating laboratories twice a year for 4 years. RESULTS: In one survey in which different crossmatch techniques were compared, flow cytometry was slightly more sensitive than the antiglobulin method and considerably more sensitive than direct cytotoxicity. However, the proportion of participants in any given survey detecting antibodies in all sera expected to be positive was 50-60% and has not changed over the years. Failure to detect antibodies correlated with low antibody concentration, diluting the unknown serum by the testing laboratory, and with the instrument used. False positive results with normal sera were infrequent. Fluorescence intensity values were not standardized and were highly variable, but when fluorescence units reported by individual laboratories were divided by their own positive-negative cutoff values, results from different centers were more comparable. In general, fluorescence-to-cutoff ratios >5 correlated with complement binding activity, whereas values <5 denoted concentrations below those required to fix complement. CONCLUSIONS: Flow cytometry, as used by most centers, is highly sensitive and allows relative antibody quantitation. Furthermore, the data define objective parameters that may help to standardize the test and improve its predictive value in clinical transplantation.

Antibodies↗

PubMed1995

Assessment of myocardial viability by ultrasonic tissue characterization.

In conclusion, myocardial tissue characterization with quantitative ultrasonic indices descriptive of the physical state of the tissue is a promising approach to complement conventional echocardiography in the evaluation of patients with coronary artery disease. In particular, differentiation among hibernating, stunned and scarred myocardium may be possible on the basis of the experience accumulated thus far.

Animals↗

PubMed2001

Evaluation of the BTA tests for the detection of bilharzial related bladder cancer: the Cairo experience.

OBJECTIVE: To evaluate the clinical performance of the BTA stat test and the BTA TRAK assay in the diagnosis of bilharzia-related bladder cancer and to calculate a new 'Egyptian' cut-off value for the BTA TRAK (quantitative) assay. METHODS: Urine samples of 149 individuals were tested for the presence of the human complement factor H-related protein, the antigen detected by the BTA stat and BTA TRAK tests. The group consisted of 53 healthy volunteers, 20 patients with active bilharziasis, 11 patients with other urologic disorders including prostate cancer, and 65 patients with histologically proven bladder cancer. All samples were obtained prior to surgery or therapy. RESULTS: The BTA stat test was positive in 64 of 65 samples from patients with bladder cancer, for an overall sensitivity of 99%. With a BTA TRAK assay cut-off of 60 U/ml (set at 97% specificity in the healthy population), the sensitivity of the TRAK assay was 94%. There was no statistically significant difference between the sensitivities of the two BTA tests in patients diagnosed with squamous cell carcinoma and those with transitional cell carcinoma. The overall specificity of the BTA stat test was 67% ranging from 15% in patients with bilharziasis to 94% in healthy volunteers. The overall specificity of the TRAK assay was 66%, again with negative results in 15% of the patients with bilharziasis. CONCLUSIONS: The BTA stat test and TRAK tests are extremely sensitive in the detection of bladder cancer in the Egyptian population. Positive results (85%) are also observed in patients with active bilharziasis, which often leads to bladder cancer. Longitudinal follow-up of these positive cases is needed to determine whether these positive results are false or predictive of bladder cancer.

Adult↗

PubMedDate not supplied

Vestibular system abnormalities in otosclerotic subjects.

A technique to quantify the tandem Romberg test (posturography) was used to study ten patients with otosclerosis before (series 1), 48 hours after (series 2), and between two to four months after (series 3) a stapedectomy. The results were analyzed by power spectrum analysis and then compared to findings from electronystagmographic testing performed with series 1 and 3. There was no significant change in the electronystagmography (ENG) test findings between series 1 and 3. Posturography, however, demonstrated an uncompensated vestibular pattern in the immediate postoperative period which, after two months, converted to a compensated vestibular pattern. Posturography serves as a useful quantitative test for the study of patients with balance disorders because the procedure supplements rather than complements the ENG. In addition, posturography detects vestibular reflex abnormalities in stapedectomized patients two months afterwards. Other testing modalities have not consistently demonstrated this postoperative vestibular system instability.

Adult↗

PubMed1992

Opsonization of middle ear bacteria during chronic suppurative and secretory otitis media.

Samples of middle ear effusion were obtained from 16 patients with chronic suppurative otitis media (COM) (20 ears, age range from 1 1/12 to 69 years) and 13 patients with secretory otitis media (SOM) (15 years, age range from 8 months to 13 8/12 years). Qualitative and quantitative bacteriological analyses of the effusions were performed and the intensity of immunoglobulin G (IgG) and complement component C3b adhering to the bacteria was estimated using immunofluorescence technique. In COM effusions, S. aureus in particular was intensely opsonized, whereas Ps. aeruginosa showed minimal, if any, coating with IgG and C3b. SOM effusions exhibited extremely sparse IgG- and C3b-coated bacteria. The difference in IgG and C3b coated bacteria between COM and SOM effusions was significant (p less than 0.01). Specific (IgG) as well as non-specific (C3b) coating of the bacteria that have gained access to the middle ear cavity is of importance for the host defence.

Adolescent↗

PubMed1992

Influence of cell cycle synchronization on digital image analysis of HL-60 granulopoiesis.

Retinoic acid (RA)-treated HL-60 cells subjected to density arrest (DA) and double thymidine block (TB) synchronization demonstrated image feature changes associated with cellular proliferation and differentiation. RA-treated TB cells demonstrated an increased level of morphologic differentiation (assessed by differential counts and quantitation of nuclear shape) and more rapid functional differentiation (assessed by superoxide production and expression of complement receptors) than RA-treated DA cells. By comparison to DA cells, TB cells had less variation in virtually all image features values. A Kruskal-Wallis test of image features ranked total optical density (TOD) of Feulgen-stained cells, nuclear area and shape factor as the top three features regardless of synchronization method. Statistically significant changes in image feature values of RA-treated cells were first noted on day 1. The computer-assisted ability to discriminate RA-treated cells on a given day after induction from paired controls by means of an unsupervised learning algorithm increased over a seven-day period for both DA and TB cells. However, in the dichotomous (RA-treated versus untreated) classification scheme employed, which did not account for continuous levels of morphologic differentiation, there was no advantage in the use of the TB over DA procedure.

Cell Count↗

PubMed1990

Human basophils express interleukin-4 receptors.

Interleukin-4 (IL-4), a multipotential lymphokine reputed to play an important role in the regulation of immune responses, interacts with a variety of hemopoietic target cells through specific cell surface membrane receptors. The present study was designed to investigate whether human basophils express IL-4 binding sites. For this purpose, basophils were enriched to homogeneity (93% and 98% purity, respectively) from the peripheral blood of two chronic granulocytic leukemia (CGL) donors using a cocktail of monoclonal antibodies (MoAbs) and complement. Purified basophils bound 125I-radiolabeled recombinant human (rh) IL-4 in a specific manner. Quantitative binding studies and Scatchard plot analysis revealed the presence of a single class of high affinity IL-4 binding sites (280 +/- 40 sites per cell in donor 1 and 640 +/- 45 sites per cell in donor 2) with an apparent dissociation constant, kd, of 7.12 x 10(-11) +/- 2.29 x 10(-11) and 9.55 +/- 3.5 x 10(-11) mol/L, respectively. KU812-F, a human basophil precursor cell line, was found to express a single class of 810 to 1,500 high affinity IL-4 binding sites with a kd of 2.63 to 5.54 x 10(-10) mol/L. No change in the numbers or binding constants of IL-4 receptors was found after exposure of KU812-F cells to rhIL-3 (a potent activator of basophils) for 60 minutes. No effect of rhIL-4 on 3H-thymidine uptake, release or synthesis of histamine, or expression of basophil differentiation antigens (Bsp-1, CD11b, CD25, CD40, CD54) on primary human CGL basophils or KU812-F cells was observed.

Antigens, Surface↗

PubMed1987

Identification of three major target molecules of IgM antilymphocyte autoantibodies in systemic lupus erythematosus.

Three cell lymphocyte antigens of m.w. 55,000, 70,000, and 105,000 to 110,000 were identified by Western blotting as targets of IgM autoantibodies in serum from a group of 49 patients with systemic lupus erythematosus. The 55- and 70-kDa antigens were well expressed on unstimulated peripheral T cells, whereas the 105- to 110-kDa target was demonstrable only on mitogen-activated T cells and lymphoblastoid T cell lines. Localization of these molecules to the plasma membrane was established by cytoabsorption experiments in which IgM antibody staining of blotted antigens was specifically absorbed from systemic lupus erythematosus serum during 4 degrees C incubations with intact lymphocytes, and by their detection in purified lymphocyte plasma membranes. While the identity of these target antigens vis a vis known surface determinants was not defined, their expression on peripheral T cells from multiple donors and on cell lines of both undifferentiated (HSB-2) and phenotypically mature (Jurkat; HUT 78) types excluded alloantigens, major histocompatibility complex-encoded determinants, and most T cell differentiation antigens as candidates in this regard. Expression of the IgM autoantibody targets on HSB-2 cells argues against discrete T subset specificities as well. IgM reactivity with the 55-, 70-, and 105- to 110-kDa antigens by blotting was highly correlated with antilymphocyte antibody activity in complement-dependent cytotoxicity assays (Fisher's p less than 0.001), and paralleled flow microfluorimetric and microcytotoxicity quantitation of IgM antibody activity in serial observations of individual patients studied during different phases of disease activity. Taken together, these data suggest that IgM lymphocytotoxic antibodies in systemic lupus erythematosus are directed predominantly against a limited number of non-T cell subset-specific antigens.

Antibody Specificity↗

PubMedDate not supplied

Differences of antigen composition of rheumatoid arthritic (RA) and non-RA derived tissue cultured synovial cells as detected by monkey anti-RA synovial cell sera.

Antisera produced in a monkey by injections of RA-derived synovial cells grown in tissue culture react preferentially with synovial cells compared to fibroblastic cell strains of other tissues. The antisera also detected differences of the antigenic components of RA and non-RA synovial cells utilizing a number of immunochemical techniques. Following adsorptions with cross-reactive antigen sources the antisera exhibited quantitative differences of reactivity to either RA or non-RA cells by immunofluorescence and complement-mediated cytotoxicity assays. The data were interpreted as indicating that fetal calf serum antigens differentially adhere to RA and non-RA synovial cells, and that antigens in synovial fluid cross-reactive with synovial cell antigens are expressed to a greater degree on RA-derived synovial cells. The results substantiate other reports that synovial cells from RA individuals are different from non-RA cells by a number of growth, metabolic and antigenic characteristics.

Adsorption↗

PubMed1995

[The genetic map of HLA].

The major histocompatibility complex (MHC) gene products are known to play a fundamental role in foreign antigen presentation to the cellular immune system. The human major histocompatibility complex (HLA) spans about 4 million base pairs (4 Mbp) of DNA at chromosome position 6p21.3 and is one of the most intensively studied regions of the human genome, containing over 70 known genes. The HLA can be divided up into three regions: the class I sequences at the telomeric end of the complex; the class II loci at the centromeric end; and, between these, the class III genes including those for the complement components. The analysis of HLA has focused primarily on their structure and function. However, the quantitative differences in gene expression are also important, since quantitative variations of cell surface HLA influences immunoregulation and the expression of immunologically mediated diseases. Recently, biochemical and genetic studies have revealed the existence of tissue-specific cis-acting regulatory gene elements and trans-acting protein factors, capable of binding to the cis-acting regions, that govern HLA gene expression.

Chromosome Mapping↗

PubMed1998

An A B C of glaucoma: apoptosis, blood flow and confocal imaging.

A clear understanding and definition of the glaucomas continues to elude the clinician. Broadening awareness of the many risk factors in glaucoma, the wide variety of presentations of the disease and greater understanding of the pattern of progression will help to improve treatment protocols. In the meantime, the diagnosis and monitoring of the disease remains a huge clinical and financial burden. Modern imaging techniques permit quantitative stereometric assessment of the optic nerve head and nerve fibre layer, affording morphologic evaluation to complement clinical psychophysical investigation.

Apoptosis↗

PubMed1980

Predictive value of serum complement (C3) in renal allograft rejection.

The purpose of this study was to investigate whether or not changes in serum concentrations of complement component C3 are of value in predicting the long term survival of the transplanted kidney. C3 was quantitated by radial immunodiffusion in fresh sera drawn immediately before transplantation and twice weekly thereafter from 10 recipients. Fourteen episodes of acute rejection occurred during the first 3 months postoperatively. These were diagnosed by the demonstration of graft tenderness, fever without evidence of infection and a rise in serum creatinine of 1 mg/dl in the absence of urinary or vascular obstruction. Five rejection episodes in 3 patients were associated with a fall in C3. In one of these patients, C3 returned to normal levels after the episode was reversed, and the kidney is functioning well 2 years after transplantation. In the other 2 patients, C3 remained at low levels regardless of anti-rejection therapy. Transplant nephrectomy was soon required for irreversible rejection. In contrast, only 1 episode unaccompanied by a fall in C3 was irreversible. Evidence is provided concerning the value of serial C3 complement determinations as a predictor of rejection in renal allografts. Using the variability measure Si, the cumulated standard deviation up to week i, Si > 10 not only predicts rejection but does so rather early, providing more than 90 per cent of the ideal lead time. This suggests that loss of a graft may be predicted, but this needs confirmation in additional cases.

Complement C3↗

PubMed1978

In vitro histamine and serotonin release by radiographic contrast media (RCM). Complement-dependent and -independent release reaction and changes in ultrastructure of human blood cells.

Peripheral leucocytes and platelets from twenty healthy volunteers were incubated in vitro with radiographic contrast media (diatrizoate-Hypaque, iothalamate-Conray and iodipamide-Cholografin) under varying conditions. All radiographic contrast media (RCM) were able to induce histamine release from peripheral leucocytes and the release reaction was dose-dependent. There were individual differences in the sensitivity of leucocytes to different RCM. The highest values (up to 80% histamine release) were found with high concentrations (0.07-0.3 M) of diatrizoate. The addition of normal human serum (NHS) to the reaction mixture led to a further increase in histamine release (P is less than 0.01), probably due to complement activation. The mechanism seems to be mediated by proteins of the alternative pathway, because serum depleted of complement components (factor B, factor D, properdin) did not show this synergistic effect. IgG-depleted serum, however, was able to show the augmented release reaction. Washed platelets incubated with RCM released serotonin in a dose- and time-dependent reaction. The most powerful serotonin-releasing RCM was found to be iodipamide, which produced a release reaction in all people investigated at concentrations of 0.04-0.09 M, while diatrizoate and iothalamate were effective only in half of the tested individuals at high concentrations (0.3 and 0.2 M respectively). The addition of plasma proteins to the reaction mixture inhibited the serotonin release quantitatively. There was no difference in inhibitory potency between autologous and heterologous plasma or serum; sera depleted of various complement components showed similar effects as NHS. The serotonin release was not due to platelet lysis, as determined by the concentration of lactic dehydrogenase present in the supernatant during serotonin release. Incubation of the leucocytes with RCM produced ultrastructural changes, including degranulation of basophils, aggregation of platelets and infiltration of the aggregates by polymorphonuclear leucocytes. The most prominent changes were observed when complement was present in the reaction mixture.

Basophils↗

PubMed2005

Intact-protein-based high-resolution three-dimensional quantitative analysis system for proteome profiling of biological fluids.

The substantial complexity and vast dynamic range of protein abundance in biological fluids, notably serum and plasma, present a formidable challenge for comprehensive protein analysis. Integration of multiple technologies is required to achieve high-resolution and high-sensitivity proteomics analysis of biological fluids. We have implemented an orthogonal three-dimensional intact-protein analysis system (IPAS), coupled with protein tagging and immunodepletion of abundant proteins, to quantitatively profile the human plasma proteome. Following immunodepletion, plasma proteins in each of paired samples are concentrated and labeled with a different Cy dye, before mixing. Proteins are subsequently separated in three dimensions according to their charge, hydrophobicity, and molecular mass. Differences in the abundance of resolved proteins are determined based on Cy dye ratios. We have applied this strategy to profile the plasma proteome for changes that occur with acute graft-versus-host disease (GVHD), following allogeneic bone marrow transplantation (BMT). Using capillary HPLC ESI Q-TOF MS, we identified 75 proteins in the micromolar to femtomolar range that exhibited quantitative differences between the pre- and post-GVHD samples. These proteins included serum amyloid A, apolipoproteins A-I/A-IV, and complement C3 that are well-known acute-phase reactants likely reflecting the post-BMT inflammatory state. In addition, we identified some potentially interesting immunologically relevant molecules including vitamin D-binding protein, fetuin, vitronectin, proline-rich protein 3 and 4, integrin-alpha, and leukocyte antigen CD97. IPAS provides a combination of comprehensive profiling and quantitative analysis, with a substantial dynamic range, for disease-related applications.

Adult↗

PubMed1980

A simple method of raising antiserum to the third fraction of mouse serum complement.

A simple method of raising antiserum to the third fraction of mouse serum complement (C3) is described. C3 was precipitated with activated zymosan and was injected with complete Freund's adjuvant subcutaneously into rabbits. The antiserum raised is monospecific and found suitable for quantitation of C3 concentration in mouse serum by single radial diffusion method.

Animals↗

PubMed1978

Activation of the alternative pathway of complement by grain. I. C3PA conversion and quantification of complement consumption by rye.

Ground whole rye and airborne rye dust of comparable size distribution were tested for their ability to activate the complement cascade via the alternative pathway. Precipitin-negative pooled normal human serum was incubated with increasing amounts of the two rye dusts. Electrophoresis of the resultant supernatant fluids demonstrated the conversion of the proactivator of the third component of complement to the gamma-migrating activator of the third component. This activation was completely prevented by pre-treating the serum with the chelator EDTA, while pre-treatment with EGTA allowed suboptimal arc conversion, strongly implying that complement was activated via the alternative pathway. Quantification of the supernanant fluids showed dose-dependent complement consumption as defined by both CH100 immunodiffusion and CH50 tube haemolytic techniques. Airborne rye dust showed a greater quantitative potential than ground whole rye for activating the alternative pathway. These results indicate the possibility of the direct action of airborne organic dusts on the induction of inflammatory sequelae in the lungs of both sensitized and unsensitized individuals.

Air Pollutants↗

PubMed1973

The nature of the antibody response to Yersinia enterocolitica serotype IX in cattle.

The nature of the antibody response of cattle to the antigen of Yersinia enterocolitica IX cross-reacting with Brucella spp. was examined. Density-gradient ultracentrifugation, ion-exchange chromatography, antibody adsorption and elution and disulphide bond reduction tests showed that both 19 S IgM and 7 S IgG(1) and IgG(2) antibodies were produced in response to the cross-reacting antigen. The highest titres of cross-reacting antibodies were detected by the agglutination and Coombs antiglobulin tests. Production of complement-fixing and precipitating antibodies cross-reacting with Br. abortus was transient and high titres were not attained.In contrast, although infection with Br. abortus also evoked cross-reacting antibodies of the IgM and IgG classes, much higher titres were produced in the complement fixation and precipitation tests and these persisted for long periods. At all stages of the serological response to both organisms, the two infections could be differentiated by the quantitative Rose Bengal plate test.

Animals↗