Faculty Bibliography

We describe here the use of northern blotting, PCR and in situ hybridization for the analysis of cytokine gene expression. These techniques, each with their advantages and disadvantages, have been used to monitor cytokine gene expression in sites of immune reactivity and in the developing thymus. Whilst expression of a gene usually correlates well with protein production from that gene, this may not always be the case. The development of methods to analyze protein production in situ, for instance by immunohistochemistry, together with analysis of mRNA expression will allow us to begin to understand the role of cytokines within the immune system of the intact animal.

Confirmation of the diagnosis of lymphedema often requires lymphangiography, a procedure that is painful for the patient and technically demanding. Radioisotope lymphoscintigraphy is a relatively new technique that uses technetium 99 m antimony trisulfide colloid to produce a diagnostic image similar to a lymphangiogram. The procedure requires a single subcutaneous injection in the involved extremity, and images are obtained 3 hours later. It is technically easy to perform, produces minimal discomfort for the patient, and has no adverse effects. We have recently used radioisotope lymphoscintigraphy to evaluate 17 patients with extremity edema. These patients initially had a presumed diagnosis of lymphedema involving the upper or lower extremity. Lymphoscintigraphy confirmed the diagnosis of lymphedema in 12 (70.6%) patients. In five of the 17 patients (29.4%) the clinical impression of lymphedema was not supported by lymphoscintigraphy, leading to alternative diagnoses such as lipomatosis, venous insufficiency (two patients), congestive heart failure, and disuse edema. In all patients with secondary lymphedema the lymphatic system in the involved extremity could be partially visualized. Conversely, three of four patients with primary lymphedema had no ascent of the tracer from the foot and no lymphatic channels could be visualized. Lymphoscintigraphy is relatively easy to perform, safe, minimally invasive, and not uncomfortable for the patient. It is useful in differentiating lymphedema from other causes of extremity edema, allowing institution of appropriate therapy.