Agent Orange studies

Article Abstract:

Agent Orange was used as a defoliating agent in the Vietnam War. There have been contradictory epidemiological reports on the effects of dioxin, a contaminant of Agent Orange, on the soldiers who were exposed to the chemical. An American Legion study published in the July 21, 1989 issue of Science by Marcia Barinaga reported adverse heath effects of Agent Orange in Vietnam veterans. However, soldiers who actually sprayed the chemical, and who have blood concentrations of dioxin that are up to seven times greater than the soldiers on the ground, do not have a higher incidence of any of the adverse health effects reported. These health effects are also not apparent in people exposed to high concentrations of dioxin during several chemical plant accidents from the 1940s to the 1970s. There is an elevated rate of the incidence of chloracne, characterized by small, black skin lesions, in the people exposed, but higher rates of cancers and other serious diseases do not occur, nor do premature deaths. Therefore, there are contradictory results between studies that link various levels of exposure to dioxin with various cancers. The Centers for Disease Control will release a study in March 1990 examining the incidence among Vietnam War veterans of six cancers, including those commonly associated with exposure to Agent Orange, soft tissue sarcomas and non-Hodgkin's lymphomas. This study will provide more information about the effects of Agent Orange on the Vietnam veterans. However, it should be understood that the American Legion study included data on troops that the Centers for Disease Control did not include in their study. The reason this data was not included is not clear, as the necessary information such as the amount of exposure to dioxin is known. There remain many controversial issues surrounding the Vietnam War, including these studies on the effect of Agent Orange on the soldiers.

Dioxin, Dioxins, American Legion, Vietnam veterans, United States. Centers for Disease Control and Prevention, Environmentally induced diseases, Environmental illness, Agent Orange, letter to the editor

---

Biohybrid artificial pancreas: long-term implantation studies in diabetic, pancreatectomized dogs

Article Abstract:

The difficulties faced by diabetics in complying with long-term regimens of daily insulin injections, and the possibility that suboptimal control of blood sugar levels causes some of the long-term complications of the disease, have prompted a search for alternatives to insulin therapy. One alternative is transplantation of pancreatic tissue, the organ whose islet cells normally manufacture insulin. However, the disadvantages to organ transplantation are considerable. Transplantation of isolated islet cells, while offering some advantages, is associated with complications, particularly that of graft rejection. This is minimized by immunosuppression, which can be accomplished by several methods. One experimental approach is the biohybrid artificial implantable pancreas, a device that consists of islet cells protected from the body's immune system by a semipermeable membrane that lets glucose, insulin, and other factors pass through, but excludes larger entities such as antibody molecules or white blood cells. The artificial pancreas is designed so that fresh islet cells (from dog or calf) can be added if necessary. This was tested on 10 dogs whose pancreases had been removed (pancreatectomized), and which required more than 10 units of insulin daily. In six (four of which needed 30 or more units daily), the device replaced exogenous insulin therapy completely. Glycemic control lasted as long as five months, but was never completely normal, particularly in its response to glycemic stress (sudden, extreme changes in glucose levels). The results indicate that the biohybrid artificial pancreas is of potential therapeutic utility for treating diabetes, and could regulate blood glucose levels in a way similar to that of the pancreas itself. (Consumer Summary produced by Reliance Medical Information, Inc.)

Health aspects, Care and treatment, Models, Diabetes, Diabetes mellitus, Transplantation of organs, tissues, etc., Organ transplantation, Tissue transplantation, Transplantation, Artificial organs, Pancreas, Pancreas transplantation

---

Protection of mice against the Lyme disease agent by immunizing with recombinant OspA

Article Abstract:

Lyme disease, a condition associated with joint, neurologic, cardiac and skin symptoms, is transmitted by the bite of Ixodes ticks; the agent that they carry and that causes the disease is Borrelia burgdorferi. A vaccine against Lyme disease needs to be developed, but characterization of an effective immune response on the part of the bitten animal or human is not complete. To learn more about this, an animal model of Lyme disease was developed. Mice were injected with a strain of B. burgdorferi called N40; they subsequently developed arthritic and cardiac symptoms. Mice that were immunized with antiserum (containing antibodies) to B. burgdorferi did not develop Lyme disease after being injected with N40. The specific antigen (protein) that elicited this immune response was then identified from several candidate molecules using gene amplification techniques. This protein (OspA), found on the surface of B. burgdorferi, was injected into mice to see whether they developed an immune response to subsequent injections of B. burgdorferi. As hoped, they did; no signs of disease were detected in mice protected in this manner. Moreover, the immune response generated after injection of OspA was strong. Whether it will protect animals against infection with different strains of B. burgdorferi remains to be seen; however, the results suggest that recombinant OspA could be investigated for its possible use as a vaccine to prevent Lyme disease. (Consumer Summary produced by Reliance Medical Information, Inc.)

Prevention, Lyme disease, Borrelia burgdorferi

Similar abstracts:

• Abstracts: Spall study in mild steel. Modeling and identification of elastic-plastic systems using the distributed-element method
• Abstracts: Strategies for remediation managers. Removing incentives for conflict. Unintended consequences
• Abstracts: The anvil of evolution. The case of the missing migrants. The gene machine
• Abstracts: The birth and death of Nova V1974 Cygni. The timing of birth
• Abstracts: Light adaptation in cat retinal rods. Retinal representations. Consequences of retinal color coding for cortical color decoding

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