Uremia and host defenses

Article Abstract:

Uremia is a condition associated with the accumulation of urea and other waste products in the blood. It is a consequence of kidney failure and the cause of approximately one-fifth of the deaths among patients suffering from this disorder. A study in the March 15, 1990, issue of The New England Journal of Medicine focused on the effects of uremic toxins on the body's defense system against infection. Patients with uremia face onslaughts to their immune systems from these toxins themselves, from deficiencies of vitamin and other substances brought on by their treatment, from the effects of dialysis filtration membranes on cells and factors in the blood, and from infectious agents that can enter the vascular system at the point where the dialysis machine is connected. These agents are responsible for about half the serious infections contracted by kidney patients. Uremia itself causes rejection of grafts and impairment of several aspects of the immune response. Reduction of defenses due to treatment effects comes about from nutritional abnormalities and changes in blood cells after repeated dialysis. The study found defects in the macrophages, blood cells specialized to remove substances from the bloodstream, including molecules already deactivated by the body's immune system. The greatest defects were found in patients in whom the worst infections later developed. Since it is known that macrophages are important agents against several types of bacteria that commonly invade patients with kidney disease, therapeutic approaches can benefit from insights gained by molecular biology to specifically enhance the responses of these cells. Such 'immunomodulating therapy' may be the next step in combating the effects of uremia. (Consumer Summary produced by Reliance Medical Information, Inc.)

Research, Abnormalities, Physiological aspects, Macrophages, Kidney diseases, Uremia

---

Rubor, dolor, calor, tumor, and radionuclide scans

Article Abstract:

Detection of suspected but hidden (occult) infections usually follows one of two paths, anatomical observation by special techniques or direct methods such as inflammation scans. While the first method works well for individuals whose anatomy is essentially intact, it works less well among patients in whom surgery, trauma or the disease process has caused distortion of the normal anatomy. Inflammation scans have proven very helpful in those cases where anatomy has been distorted. A recent method of inflammation scanning uses a substance (indium-111-labeled IgG; human gammaglobulin) which is very sensitive to inflammation (91 percent) and totally specific at detecting inflammation and nothing else. In recent research, this new method allowed rapid identification of inflammation and was found to be cheaper, easier, and more easily detected than previous scanning methods of identification. The method also uses less radioactivity and is more suitable for examining children because it does not require the collection of a large volume of white blood cells as do other methods. The IgG-labelled method does have several major problems, including uptake by the liver and spleen, reduced uptake in some conditions, and false negative results in patients with low-grade infection. Although the specific biochemical or physiologic mechanisms that permit the technique are currently unknown, they may involve interactions of inflammatory products or cells with the labelled IgG. In cases where anatomic relationships remain intact, anatomic means of assessing inflammation remain the first choice; however, new nuclear medical techniques including inflammation scanning with IgG can be extremely helpful in other cases.

---

In-labeled nonspecific immunoglobulin scanning in the detection of focal infection

Article Abstract:

Knowledge of the exact location and degree of infection within the cavities of the body is critical for diagnosis and selecting the best course of treatment. Although various clinical imaging techniques such as CAT scanning, ultrasound and magnetic resonance imaging are all useful, interpretation of their images is often difficult after the anatomical disruption induced by surgery. A simple test is presented to identify inflammation using a radioactively labeled human immunoglobulin (IgG) that is simply injected into the patient and detected by a nuclear camera. Immunoglobulins are proteins that are active in the immune response. The IgG scan was able to find localized areas of inflammation that were confirmed by other diagnostic methods in 51 infected patients. There were no false positive identifications in the population of 63 noninflamed patients who were also examined. When the inflammation was treated, treatment was successfully followed by repeating the IgG scan. There is also indication that IgG scanning may help identify infections that frequently arise within the vascular system when such prosthetic devices as heart valves are put in place. Results also suggest that the method will allow evaluation of orthopedic (joint) inflammation as in arthritis. In an attempt to discover if the test was specific for inflammation, a group of 16 patients with various cancers were similarly examined. In 13 of this group localization of IgG was found to occur in the area of tumor, a finding that may prove useful for scanning for occult (undiscovered) tumor.

Infection

Similar abstracts:

• Abstracts: Head and neck cancer. Clonal origin of bladder cancer
• Abstracts: Chemical and biological warfare: should defenses be researched and deployed? The use of chemical weapons; conducting an investigation using survey epidemiology
• Abstracts: Pulmonary neoplastic and lymphoproliferative disease in AIDS: a review. Parasternal sonography of the internal mammary vessels: technique, normal anatomy, and lymphadenopathy
• Abstracts: Expanding AIDS drug availability. HIV/AIDS care calls for reallocation of resources. Coma-inducing drug GHB may be reclassified
• Abstracts: Intestinal electrolyte transport and diarrheal disease. Diarrheal disease during Operation Desert Shield

This website is not affiliated with document authors or copyright owners. This page is provided for informational purposes only. Unintentional errors are possible.