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Method of TCR-γ gene rearrangement
Method of TCR-γ gene rearrangement

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RESEARCH TECHNIQUES MADE SIMPLE: ENZYME IMMUNOASSAY (EIA) and ENZYME-LINKED IMMUNOSORBENT ASSAY (ELISA): Q&A

The questions and answers below relate to the Research Techniques Made Simple article  “Enzyme Immunoassay (EIA) and Enzyme-Linked Immunosorbent Assay (ELISA),” published online with the September 2013 issue of JID.

 

Correct answers appear in bold underline.

 

Multiple Choice Questions & Answers:

 

1.    Which of the following molecule(s) can be detected by ELISA?

a)     proteins

b)     hormones

c)     antibodies

d)     all of the above

 

2.     What does a weak color signal in competitive ELISA represent?

a)     more antigen in the sample

b)     less antigen in the sample

c)     less antigen retained on the well

d)     both a and c

 

3.    Which of the following is immobilized on the microtiter well in sandwich ELISA?

a)    detection antibody

b)    sample

c)    capture antibody

d)    secondary antibody conjugated to an enzyme

 

4.    What is a major advantage of ELISA in comparison to other biological quantification techniques?

a)    detection of a molecule at a low concentration

b)    inexpensive

c)    low specificity

d)    easily available

Research Techniques Made Simple: COMPARATIVE EFFECTIVENESS RESEARCH

For details, we refer you to the article “Research Techniques Made Simple:  COMPARATIVE EFFECTIVENESS RESEARCH” by Vinod E Nambudiri and Abrar Qureshi at http://www.jidonline.org.

 

Questions

1.  Study designs used for comparative effectiveness research include:

a) Systematic review

b) Randomized controlled trial

c) Cross sectional study

d) All of the above

 

2. Differences in survival between two treatment groups are best compared using which of the following statistical methods?

a) Paired t-test

b) Log-rank test

c) ANOVA

d) Fisher’s exact test

 

3. The intraclass correlation coefficent representing the best degree of agreement between two diagnostic tools among the following is:

a) ICC < 0.01

b) ICC = 0.05

c) ICC = 0.50

d) ICC = 0.95

 

____________________________________

 

Answers:

 

1.  Study designs used for comparative effectiveness research include:

d) All of the above

 

2. Differences in survival between two treatment groups are best compared using which of the following statistical methods?

               b) Log-rank test

 

3. The intraclass correlation coefficent representing the best degree of agreement between two diagnostic tools among the following is:

               d) ICC = 0.95

 

Research Techniques Made Simple: IMMUNOFLUORESCENCE Q&A

For details, we refer you to the article “Research Techniques Made Simple: Immunofluorescence Techniques” by Ian D. Odell1, MD, PhD and Deborah Cook2, MD

Departments of Medicine1 and Pathology2 University of Vermont College of Medicine, Burlington, VT

Questions

  1. What is the purpose of Michel’s solution?
    1. Fix the tissue before detection
    2. Cross link cellular components to retain the integrity of cellular structures
    3. Disrupt plasma membranes to give antibodies access to their target antigens
    4. Precipitate the immune complexes to preserve antigenicity

 

  1. How many additional antibodies are required to detect autoimmune complexes?
    1. 1
    2. 2
    3. 3
    4. 4

 

  1. Which of the following techniques is more sensitive than immunofluorescence for the diagnosis of some autoimmune bullous diseases?
    1. Light microscopy
    2. ELISA
    3. Dermatoscope
    4. Western blot

Answers

1. D

2. A

3. B

RESEARCH TECHNIQUES MADE SIMPLE: CONFOCAL MICROSCOPY Q&A

These questions and answers relate the the article “RESEARCH TECHNIQUES MADE SIMPLE:  INTRODUCTION TO CONFOCAL MICROSCOPY” by Nwaneshiudu et al.  For details see the December 2012 issue of JID.

 

 

QUESTIONS

 

1) Features of confocal microscopy include which of the following:

a. Formation of the focal point of the objective lens on a pinhole to decrease “noise”

b. Increase in the optical resolution and contrast of the image

c. Ability to reconstruct a 3-D image of the specimen

d. Ability to collect serial optical sections from thick specimens

e. All of the above

 

 

2) Which microscope uses a series of moving pinholes on a disk?

a. Programmable array microscope

b. Spinning-disk confocal microscope

c. Scanning transmission electron microscope

d. Phase-contrast microscope

 

 

3)  What is the role of a photomultiplier tube?

a. It collects fluorescence at the dichroic mirror
b. It provides the excitation light

c. It scans the emitted light
d. It detects the emitted light

 

4)  What may be the consequence of using two different fluorescent dyes?

a. Photobleaching

b. Phototoxicity

c. Chromatic and spherical aberration
d. Less detectable photons

 

ANSWERS

1) Features of confocal microscopy include which of the following:

e:  All of the above.

 

 

2) Which microscope uses a series of moving pinholes on a disk?

b:  Spinning-disk confocal microscope

 

3)  What is the role of a photomultiplier tube?

d:  It detects the emitted light

 

4)  What may be the consequence of using two different fluorescent dyes?

c:  Chromatic and spherical aberration

Research Techniques Made Simple — FLOW CYTOMETRY Q&A

RTMS-FlowCytometry.jpg

These questions and answers relate to the Research Techniques Made Simple article on FLOW CYTOMETRY by Richard R. Jahan-Tigh, Caitriona Ryan, Gerlinde Obermoser, and Kathryn Schwarzenberger in the October 2012 issue of JID.

We welcome your comments on the article and the quiz!

QUESTIONS:

1. Side Scatter (SSC) and Forward Scatter (FSC) provide information on ___________ and _________ , respectively.

A. tissue architecture, granularity
B. granularity, size
C. size, cell-cell interactions
D. cell-surface markers, intracellular signaling

2. “Gating” refers to:

A. the process of cells lining up single-file before entering the laser path.
B. the field the cells enter during the sorting process.
C. the restriction of a portion of the analyzed cells for further analysis.
D. the overlapping fluorophore signals generated in flow experiments with many fluorophores.

3. In a fluorescent by fluorescent scatter plot, cells present in the upper right quadrant of the plot are generally:

A. negative for one marker, positive for the other.
B. negative for both markers.
C. positive for aberrant marker expression.
D. positive for both markers.

ANSWERS:

1. B
Side scatter provides information that correlates to the cell granularity while forward scatter is a marker of cell size. With the aid of these two parameters and a few other stains, commercial blood analyzers are able to generate complete blood counts (CBC) with differentials. Remember, flow cytometry cannot provide information on tissue architecture or cell-cell interactions, as the cells must be suspended in solution for flow analysis. Flow cytometry can provide information on cell surface markers and intracellular signaling, but this is performed using fluorophore labeled antibodies, while measuring SSC and FSC does not require antibodies.

2. C
Gating refers to the process of selecting cell subsets of interest from parent populations during flow cytometry data analysis. For example, in a blood sample forward and side scatter can be used to define the lymphocyte region, and a second gate can be placed around CD3+ cells to discern them from CD3- natural killer cells. The field that the cells enter for a sorting is usually an electromagnetic field that separates based on charge. The overlapping signals generated from multiple fluorophores are termed “spillover”.

3. D
The interpretation of the basic fluorescent by fluorescent scatter plot is important, as virtually all flow experiments employ them. Cells in the upper right are positive for both markers, while cells in the bottom left are generally negative for both markers. The other two quadrants are negative for one marker and positive for the other as depicted in Figure 1ciii. Also, the axes for fluorescent by fluorescent plots are displayed logarithmically, meaning that even small visual differences reflect potentially large differences in fluorophore expression.

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