217 research outputs found
Glomerular thrombosis in pregnancy: Role of the L-arginine-nitric oxide pathway
Glomerular thrombosis in pregnancy: Role of the L-arginine-nitric oxide pathway. E. coli endotoxin (LPS) and certain cytokines induce synthesis of nitric oxide (NO) from L-arginine, but also promote endothelial injury and intravascular coagulation. NO has vasodilator and antithrombogenic properties. We investigated the relationship between the L-arginine-NO pathway and the susceptibility to LPS-induced glomerular thrombosis in pregnancy. Pregnant rats were given either 0.15 or 0.75 mg/kg/body wt of LPS intraperitoneally. In rats given 0.15 mg/kg/body wt of LPS urinary NO2−/NO3− (end products of NO) increased 200% (P < 0.05), plasma L-arginine did not change, and glomerular thrombosis was minimal. Pregnant rats given 0.75 mg/kg/body wt of LPS developed glomerular thrombosis in 75% of glomeruli (P < 0.05). In these rats plasma L-arginine fell 98%, from 53 ± 4 to 1.4 ± 0.9 mmol/liter (P < 0.05) but the urinary NO2−/NO3− did not increase. Oral administration of L-arginine but not D-arginine increased urinary NO2−/NO3− by 250% and averted glomerular thrombosis in these rats (P < 0.05). Virgin rats given 0.75 mg/kg/body wt of LPS did not contract glomerular thrombosis. In these rats plasma L-arginine decreased only 40% while urinary NO2−/NO3− concomitantly increased over 200% (P < 0.05). Plasma endothelin-1 increased only in rats exhibiting glomerular thrombosis. Thus, limited maternal reserve capability for NO synthesis may underlie, at least in part, the susceptibility for glomerular thrombosis in pregnancy
The Rose Bengal Test in Human Brucellosis: A Neglected Test for the Diagnosis of a Neglected Disease
Brucellosis is a highly contagious zoonosis affecting livestock and human beings. The human disease lacks pathognomonic symptoms and laboratory tests are essential for its diagnosis. However, most tests are difficult to implement in the areas and countries were brucellosis is endemic. Here, we compared the simple and cheap Rose Bengal Test (RBT) with serum agglutination, Coombs, competitive ELISA, Brucellacapt, lateral flow immunochromatography for IgM and IgG detection and immunoprecipitation with Brucella proteins. We tested 208 sera from patients with brucellosis proved by bacteriological isolation, 20 contacts with no brucellosis, and 1559 sera of persons with no recent contact or brucellosis symptoms. RBT was highly sensitive in acute and long evolution brucellosis cases and this related to its ability to detect IgM, IgG and IgA, to the absence of prozones, and to the agglutinating activity of blocking IgA at the pH of the test. RBT was also highly specific in the sera of persons with no contact with Brucella. No test in this study outperformed RBT, and none was fully satisfactory in distinguishing contacts from infected patients. When modified to test serum dilutions, a diagnostic titer >4 in RBT resulted in 87.4% sensitivity (infected patients) and 100% specificity (contacts). We discuss the limitations of serological tests in the diagnosis of human brucellosis, particularly in the more chronic forms, and conclude that simplicity and affordability of RBT make it close to the ideal test for small and understaffed hospitals and laboratories
Selective IgA Deficiency
Immunoglobulin A (IgA) deficiency is the most common primary immunodeficiency defined as decreased serum level of IgA in the presence of normal levels of other immunoglobulin isotypes. Most individuals with IgA deficiency are asymptomatic and identified coincidentally. However, some patients may present with recurrent infections of the respiratory and gastrointestinal tracts, allergic disorders, and autoimmune manifestations.
Although IgA is the most abundant antibody isotype produced in the body, its functions are not clearly understood. Subclass IgA1 in monomeric form is mainly found in the blood circulation, whereas subclass IgA2 in dimeric form is the dominant immunoglobulin in mucosal secretions. Secretory IgA appears to have prime importance in immune exclusion of pathogenic microorganisms and maintenance of intestinal homeostasis. Despite this critical role, there may be some compensatory mechanisms that would prevent disease manifestations in some IgA-deficient individuals.
In IgA deficiency, a maturation defect in B cells to produce IgA is commonly observed. Alterations in transmembrane activator and calcium modulator and cyclophilin ligand interactor gene appear to act as disease-modifying mutations in both IgA deficiency and common variable immunodeficiency, two diseases which probably lie in the same spectrum. Certain major histocompatibility complex haplotypes have been associated with susceptibility to IgA deficiency.
The genetic basis of IgA deficiency remains to be clarified. Better understanding of the production and function of IgA is essential in elucidating the disease mechanism in IgA deficiency
Recommended from our members
US assistance in physical protection at the Kharkov Institute of Physics and Technology and the Sevastopol Institute of Nuclear Energy and Industry, Ukraine
The U.S. DOE is providing nuclear material safeguards assistance in both material control & accountability and physical protection to several nuclear facilities in Ukraine. This paper describes the types of physical protection upgrades that are presently being implemented at the Kharkov Institute of Physics and Technology and at the Sevastopol Institute of Nuclear Energy and Industry. These upgrades include: hardening of storage areas, improvements in access control, intrusion detection, CCTV assessment, alarm monitoring and voice communication systems. Methods used to implement these upgrades and problems encountered are discussed. 4 refs., 2 figs
Recommended from our members
Status of U.S. programs for material protection, control & accounting assistance to Ukraine and Kazakstan
The United States is one of several donor states providing technical assistance to the Newly Independent States (NIS) of the Former Soviet Union (FSU) for improving their systems for control of nuclear materials. Ukraine and Kazakstan have significant nuclear energy programs. Both countries have committed to nonproliferation of nuclear weapons. They have signed the NPT and have safeguards agreements with the U.S. concerning development of state systems of control, accounting and physical protection of nuclear materials. As directed by the DOE - International Safeguards Division (now the DOE - Russia/NIS Nuclear Materials Security Task Force), technical specialists from several national laboratories, including Argonne, Los Alamos, Oak Ridge, Pacific Northwest and Sandia, as well as representatives of other U.S. Government organizations, such as the NRC, DOD/DNA and the New Brunswick Laboratory, are interacting with government regulatory and facility personnel of Ukraine and Kazakstan. Argonne has program coordination responsibilities for both countries. In support of agreements between the U.S. and Ukraine and the U.S. and Kazakstan, the DOE is responsible for providing technical assistance and training to aid in the evaluation, design, development, and implementation of nuclear material safeguards. This assistance includes: (1) information systems for tracking and reporting the location of nuclear materials, (2) application of nuclear measurement techniques for verifying inventories, (3) material control and accounting (MC&A) systems, and (4) physical protection (PP) systems. Site survey teams, including both MC&A and PP experts from several national labs, have visited Ukraine and Kazakstan. This paper summarizes activities to date and future plans
- …