scholarly journals Biotin interference in several electrochemiluminescence immunoassays (eclia)

2021 ◽  
Vol 87 (87(03)) ◽  
pp. 239-246
Author(s):  
José Luis Martín-Calderón
Keyword(s):  
Bone Markers ◽  
Critical Level ◽  
Endocrine Tumor ◽  
Relative Bias ◽  
Microsoft Excel ◽  
Ca 15.3 ◽  
High Bias ◽  
Medical Importance ◽  
Sandwich Assays ◽  
Phosphate Buffered Saline

– Background: The aim of this study is to define the interference of biotin in several endocrine, tumor marker, and vitamin assays performed by an electrochemiluminescence method, trying to determinate the critical level that causes biotin interference. – Material and methods: Working biotin solutions were prepared in phosphate-buffered saline (PBS) at different concentrations (10000, 7500, 5000, 2500, 1250, 625, and 312.5 ng/mL), which were spiked on the samples to obtain final concentrations ten-fold lower. Each serum biotin dilution was tested in triplicate, using at least two levels of analytes. Determinations of several endocrine, vitamins, tumor and bone markers were carried-out with eletrochemilumenescent immunoassays on the cobas e801 and cobas e411. Comparison between the results obtained by analyzing the biotin-spiked samples and the reference PBS-spiked samples was performed using Microsoft Excel. The relative bias with the interfering-free specimen was calculated for each biotin concentration. Interference was considered significant when the relative bias exceeded 10%. Glick´s interferographs were performed plotting the percentage of change vs. biotin concentration. – Results: Analyte concentrations were spuriously decreased in 12 sandwich immunoassays and falsely increased in 11 competitive immunoassays. However thyrotropin and CA 15.3 antigen were not significantly affected. – Conclusions: Except CA 15.3 and TSH, the methods tested were susceptible to biotin interference. Falsely low values occurred in sandwich assays and high bias in competitive assays. Clinicians and laboratorians should be aware of the medical importance of biotin interference as a cause of misdiagnosis and incorrect treatment.

Ultrastructure of developing visual cortical synapses in the cat superior colliculus

1991 ◽  
Vol 49 ◽  
pp. 156-157
Author(s):  
Caroline A. Miller ◽  
Laura L. Bruce
Keyword(s):  
Superior Colliculus ◽  
Phosphate Buffer ◽  
Receptive Fields ◽  
Visual Cortical Area ◽  
Cortical Synapses ◽  
Visual Cortical ◽  
And Function ◽  
Phosphate Buffered Saline ◽  
The Brain ◽  
Cat Superior Colliculus

The first visual cortical axons arrive in the cat superior colliculus by the time of birth. Adultlike receptive fields develop slowly over several weeks following birth. The developing cortical axons go through a sequence of changes before acquiring their adultlike morphology and function. To determine how these axons interact with neurons in the colliculus, cortico-collicular axons were labeled with biocytin (an anterograde neuronal tracer) and studied with electron microscopy.Deeply anesthetized animals received 200-500 nl injections of biocytin (Sigma; 5% in phosphate buffer) in the lateral suprasylvian visual cortical area. After a 24 hr survival time, the animals were deeply anesthetized and perfused with 0.9% phosphate buffered saline followed by fixation with a solution of 1.25% glutaraldehyde and 1.0% paraformaldehyde in 0.1M phosphate buffer. The brain was sectioned transversely on a vibratome at 50 μm. The tissue was processed immediately to visualize the biocytin.

Artifact-free electron microscopic immunocytochemistry on rat brain tissue

1991 ◽  
Vol 49 ◽  
pp. 272-273
Author(s):  
Veronika Burmeister ◽  
N. Ludvig ◽  
P.C. Jobe
Keyword(s):  
Microscopic Examination ◽  
Free Electron ◽  
Electron Microscopic Examination ◽  
Ultrastructural Localization ◽  
Rabbit Serum ◽  
Electron Microscopic ◽  
Electron Microscopic Immunocytochemistry ◽  
Phosphate Buffered Saline ◽  
Rat Brain Tissue ◽  
Immune Rabbit

Electron microscopic immunocytochemistry provides an important tool to determine the ultrastructural distribution of various molecules in both normal and pathologic tissues. However, the specific immunostaining may be obscured by artifactual immunoreaction product, misleading the investigator. Previous observations show that shortening the incubation period with the primary antibody from the generally used 12-24 hours to 1 hour substantially reduces the artifactual immunostaining. We now extend this finding by the demonstration of artifact-free ultrastructural localization of the Ca2/calmodulindependent cyclic nucleotide phosphodiesterase (CaM-dependent PDE) immunoreactivity in brain.Anesthetized rats were perfused transcardially with phosphate-buffered saline followed by a fixative containing paraformaldehyde (4%) and glutaraldehyde (0.25%) in PBS. The brains were removed, and 40μm sections were cut with a vibratome. The sections were processed for immunocytochemistry as described by Ludvig et al. Both non-immune rabbit serum and specific CaM-dependent PDE antibodies were used. In both experiments incubations were at one hour and overnight. The immunostained sections were processed for electron microscopic examination.

Modified gach technique vs critical point drying: Shrinkage analysis for SEM

1987 ◽  
Vol 45 ◽  
pp. 954-955
Author(s):  
B. Thompson ◽  
N. Sculov ◽  
R.E. Crang
Keyword(s):  
Critical Point ◽  
Calf Serum ◽  
Drying Shrinkage ◽  
Specimen Preparation ◽  
Cell Shrinkage ◽  
Whole Cells ◽  
Critical Point Drying ◽  
Prepared Material ◽  
Inverted Microscope ◽  
Phosphate Buffered Saline

The use of co-polymerized glutaraldehyde-carbohydrazide (GACH) was proposed for specimen preparation in scanning electron microscopy (SEM) as a means of avoiding dehydration in organic solvents, and to provide dimensionally stable biological specimens through a process of air-drying. It has been assumed that shrinkage of specimens prepared by the GACH technique should be less than that of conventionally-prepared material by critical point drying (CPD). In a previous study, Bell has reported significant shrinkage of whole cells for SEM. This report compares cell shrinkage in GACH and CPD preparations.Fibroblasts from newborn rats were grown on collagen-coated glass cover-slips (with alpha numeric grids etched onto the surface of the coverslips) in Eagle's minimum essential medium + 10% fetal calf serum for 7 d. (3). Using an inverted microscope with phase-contrast optics, micrographs were taken of the cultures in their live state and 1 h. after fixation with 2.5% glutaraldehyde in Dulbecco's phosphate buffered saline (Figs. 1 and 3).

Cell surface changes during aging of human bladder epithelium examined by lectin probes and SEM

1990 ◽  
Vol 48 (3) ◽  
pp. 966-967
Author(s):  
J. Jacob ◽  
M.F.M. Ismail
Keyword(s):  
The Elderly ◽  
Ultrastructural Changes ◽  
Pokeweed Mitogen ◽  
Asymmetric Structure ◽  
Luminal Surface ◽  
Bladder Epithelium ◽  
Aldehyde Groups ◽  
Cell Surface Changes ◽  
Phosphate Buffered Saline ◽  
Surface Changes

Ultrastructural changes have been shown to occur in the urinary bladder epithelium (urothelium) during the life span of humans. With increasing age, the luminal surface becomes more flexible and develops simple microvilli-like processes. Furthermore, the specialised asymmetric structure of the luminal plasma membrane is relatively more prominent in the young than in the elderly. The nature of the changes at the luminal surface is now explored by lectin-mediated adsorption visualised by scanning electron microscopy (SEM).Samples of young adult (21-31 y old) and elderly (58-82 y old) urothelia were fixed in buffered 2% glutaraldehyde for 10 m and washed with phosphate buffered saline (PBS) containing Ca++ and Mg++ at room temperature. They were incubated overnight at 4°C in 0.1 M ammonium chloride in PBS to block any remaining aldehyde groups. The samples were then allowed to stand in PBS at 37°C for 2 h before incubation at 37°C for 30 m with lectins. The lectins used were concanavalin A (Con A), wheat germ agglutinin (WGA), phytohaemagglutinin (PHA) and pokeweed mitogen (PWM) at a concentration of 500 mg/ml in PBS at pH 7.A.

Immunocytochemical localization of p65 with one-nanometer gold particles following silver development

1989 ◽  
Vol 47 ◽  
pp. 1042-1043
Author(s):  
Richard W. Burry ◽  
Diane M. Hayes
Keyword(s):  
Plasma Membrane ◽  
Bovine Serum Albumin ◽  
Calf Serum ◽  
Specific Protein ◽  
Immunocytochemical Localization ◽  
Electron Microscopic ◽  
Gold Particles ◽  
Pass Through ◽  
Label Distribution ◽  
Phosphate Buffered Saline

Electron microscopic (EM) immunocytochemistry localization of the neuron specific protein p65 could show which organelles contain this antigen. Antibodies (Ab) labeled with horseradish peroxidase (HRP) followed by chromogen development show a broad diffuse label distribution within cells and restricting identification of organelles. Particulate label (e.g. 10 nm colloidal gold) is highly desirable but not practical because penetration into cells requires destroying the plasma membrane. We report pre-embedding immunocytochemistry with a particulate marker, 1 nm gold, that will pass through membranes treated with saponin, a mild detergent.Cell cultures of the rat cerebellum were fixed in buffered 4% paraformaldehyde and 0.1% glutaraldehyde (Glut.). The buffer for all incubations and rinses was phosphate buffered saline with: 1% calf serum, 0.2% saponin, 0.1% gelatin, 50 mM glycine 1 mg/ml bovine serum albumin, and (not in the HRP labeled cultures) 0.02% sodium azide. The monoclonal #48 to p65 was used with three label systems: HRP, 1 nm avidin gold with IntenSE M development, and 1 nm avidin gold with Danscher development.

The use of 1nm silver enhanced gold probes for the detection of skin antigens

1990 ◽  
Vol 48 (3) ◽  
pp. 902-903
Author(s):  
J.P Cassella ◽  
H. Shimizu ◽  
A. Ishida-Yamamoto ◽  
R.A.J. Eady
Keyword(s):  
Type Iv Collagen ◽  
Freeze Substitution ◽  
Collagen Type Iv ◽  
Electron Microscopic ◽  
Normal Human Skin ◽  
Type Iv ◽  
Type Vii Collagen ◽  
Keratin Filaments ◽  
Normal Human ◽  
Phosphate Buffered Saline

1nm colloidal gold with silver enhancement has been used in conjunction with a low-temperature post-embedding (post-E) technique for the demonstration of skin antigens at both the light microscopic (LM) and electron microscopic (EM) levels.Keratin filaments and basement membrane zone (BMZ) associated antigens in normal human skin (NHS) were immunolabelled using antibodies against keratin 14, 10, and 1, the carboxy-terminus and collagenous portion of type VII collagen, type IV collagen and bullous pemphigoid antigen (BP-Ag).Fresh samples of NHS were cryoprotected in 15% glycerol, cryofixed in propane at -190°C, subjected to freeze substitution in methanol at -80°C and embedded in Lowicryl K11M at -60°C. Polymerisation of the resin was initiated under UVR at - 60°C for 48 hours and continued at room temperature for a further 48 hours. Semith in sections were air dried onto slides coated with 3-aminopropyltriethoxysilane. The following immunolabelling protocol was adopted: Primary antibody was applied for 2 hours at 37°C or overnight at 4°C. Following washing in Dulbecco’s phosphate buffered saline (PBSA) a biotinylated secondary antibody was applied for 2 hours at 37°C. The sections were further washed in PBSA and 1nm gold avidin was applied. Sections were finally washed in PBSA and silver enhanced.

Current Issues: Advanced Digital Technology for Supervising Graduate Clinicians

2010 ◽  
Vol 20 (1) ◽  
pp. 9-13 ◽  
Author(s):  
Glenn Tellis ◽  
Lori Cimino ◽  
Jennifer Alberti
Keyword(s):  
Real Time ◽  
Digital Technology ◽  
Clinical Training ◽  
State Of The Art ◽  
Clinical Skills ◽  
Slow Motion ◽  
Video Capture ◽  
Microsoft Excel ◽  
Clinical Supervisors ◽  
Training And Supervision

Abstract The purpose of this article is to provide clinical supervisors with information pertaining to state-of-the-art clinic observation technology. We use a novel video-capture technology, the Landro Play Analyzer, to supervise clinical sessions as well as to train students to improve their clinical skills. We can observe four clinical sessions simultaneously from a central observation center. In addition, speech samples can be analyzed in real-time; saved on a CD, DVD, or flash/jump drive; viewed in slow motion; paused; and analyzed with Microsoft Excel. Procedures for applying the technology for clinical training and supervision will be discussed.

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