Being an old timer, I have been around since before the advent of vials of glutaraldehyde. In the 1970s, the Merck index described a method for purifying glutaraldehyde using activated charcoal.

Basically, glutaraldehyde begins to polymerize when stored at room temperature. Since best fixation is achieved with the monomeric form, this purification protocol was designed to remove the more complex forms. Storage under nitrogen in a sealed vial slows the polymerization, and lower concentrations degrade more slowly. Storing at 4°C is advised.

Interplanetary dust particles (IDPs) comprise an important source of extraterrestrial materials available for study of our solar system and originate from either the asteroid belt or from short period comets. IDPs from cometary sources are particularly important as they constitute the only physical samples of comets available; all known meteorites are derived from the asteroids, the Moon or Mars. By measuring the densities of IDPs and using an appropriate atmospheric entry heating model, it is possible to determine whether an individual IDP has been derived from an asteraidal or cometary source region. Calculating the density of an IDP requires knowledge of both its mass and volume, which can be determined by using a combination of secondary and transmission electron microscopy techniques. We have developed methods to measure both of these parameters and thus routinely measure densities for individual IDPS in the size range of 5-15 μm.

With the advent of Mohs surgery in the dermatology clinics, making sure the margins are clear of any cancer is of the utmost importance to both patient and dermatopathologist. While the patient is stiil in the surgery suite, immunohistochemistry staining can be done in the laboratory microwave (Pelco microwave with waiter load cooler wattage controller arid temperature probe). The immunohistochemistry procedure takes only 25-30 minutes as compared to the more conventional methods that take 2 hours or more.

The microwave needs to be checked for hot spots using the Pelco #36140 microwave bulb array. Make sure the area in which you are going to put your slides has no hot spots, indicated by no illuminating bulbs. Using a Sigma Diagnostics #H6644 Humid Chamber; place a paper towel in the bottom of the chamber and fill with 1/4 inch of water.

Small tissues are always difficult to work with. The limited size often leads to many technical problems. In spite of the care normally given to a specimen, the unthinkable can happen. A block may be cut through, slides may be broken, and sections may fall off. When this type of tragedy occurs, the creativity and technical abilities of a histology technician are often tested.

An example of this occurred when a technician was cutting a prostate biopsy. Two slides were taken, with two sections on each. The slides were taken, with two sections on each. The slides were stained with hematoxylin and eosin (H&E), and coverslipped with a Tissue Tek automatic coverslipper. This coverslipper uses a plastic film, which causes the film to adhere to the slide with xylene. The slides were then given to the pathologist who then requested an immunohistochemical (IHC) test to be performed. In the process, the specimen was exhausted.