Cholesterol (lipid) assays

Circulating levels of cholesterol in the blood play an important role in the health of an individual. High levels of total cholesterol and low-density lipoprotein (LDL, or 'bad') cholesterol increase your risk of developing heart disease and other cardiovascular-related diseases. However, high levels of high-density lipoprotein (HDL, or 'good') cholesterol act as a protective mechanism against heart and other cardiovascular-related diseases. The relationship between cholesterol levels and eye health are no exception. Perturbed cholesterol metabolism may play a role in age-related macular degeneration or retinal vein occlusion. Furthermore, cholesterol species form part of a greater lipid profile; circulating lipid species and lipid metabolism are essential aspects of eye health and disease. That said, an element of the Jiri Eye Study is measuring levels of total cholesterol, HDL cholesterol, and LDL cholesterol (empirically determined) in the serum of every individual participating in the study.

A single serum chiclet is used for the cholesterol assays.

Getting a serum chiclet ready for the clinical chemistry analyzer.

Clinical chemistry analyzer running cholesterol assay: positive control.

Clinical chemistry analyzer running cholesterol assay: study sample.

Screen output: positive control.

Screen output: study sample.

Making chiclets

Not to be confused with the candy-coated chewing gum, the chiclets we make in the laboratory is an ingenious way of preserving sample integrity. Developed by one of our esteemed STDOI professors, Dr. John VandeBerg, our chiclet protocol is a simple yet elegant way of making sample (serum or plasma) aliquots. Chiclet aliquots minimizes the freeze/thaw cycles a serum or plasma sample endures, therefore maintaining the integrity of the sample for numerous biochemical assays now and in the future.

Serum samples thawing.

Serum will be fed into tubing.

Tubing, with serum is passed through a heat sealer.

And presto! Serum chiclets are made!

Serum chiclet storage tubes labelled and ready.

Serum chiclets in their new long term 'home'.

Sample cataloging/inventory

It's been a few months now since we've been back. Things have been busy but we've now managed to catalog and store away the blood and serum samples. As it is with any other project, the time and effort it takes to set up a well characterized and well documented sample catalog is imperative for any future work that requires access to the samples. To know the location of a sample we generally document the following information: Freezer ID, freezer shelf number, the freezer rack on the shelf, the freezer rack row, the position of the sample box in the freezer rack row, and coordinates (A1, A2,...) within the sample freezer box.

Serum samples ready to be  placed in freezer storage box.  Samples are kept on dry ice to  prevent thawing.

Blood clots all packed away.  The displayed sample is in sample  box position A4.

Serum and blood clots stored away. On the  freezer shelf we see five freezer racks each with  three rows. Different sized freezer racks are due  to the size and shape of the sample tube.

To maintain sample integrity, all samples are stored at  -80 to -83 degrees Celsius (-112 to -117 Fahrenheit). At these temperatures protective equipment (cryo-gloves, lab coat, safety glasses/face shield) must be worn, otherwise cold burns may occur.