A total of 291 unvaccinated sheep from Brucella melitensis-infected flocks were examined for delayed-type hypersensitivity (DTH) responses with Brucellergene commercial allergen and with cold saline extract and cytosol from rough B. melitensis 115, and their sera were tested in the rose bengal test (RBT), complement fixation test (CFT), and enzyme-linked immunosorbent assay (ELISA) with lipopolysaccharide. DTH reactions were maximal after 72 h, with no intensity differences among allergens, inoculation sites (eyelid and tail), and doses tested. There were no differences in the results recorded by visual inspection and palpation of inoculation sites, by measuring skin thickness with a caliper, or by microscopic examination of samples taken at necropsy. Six days after DTH testing, anergy was observed in 100%Yo of the animals, and 100%v reactivity was recovered only after 24 days. All animals were necropsied, and thorough bacteriological searches were performed. The sensitivities found with the 140 animals from which B. melitensis was isolated were ELISA, 100%o; DTH, 97.1%; RBT, 92.1%; and CFT, 88.6%. Those results put into question the value of RBT and CFT as screening and confirmatory tests for sheep brucellosis and at least indicate that their standardization should be modified. For 151 tested sheep from which B. melitensis was not isolated, the percentages of positive animals were ELISA, 100%o; DTH, 94.0%; RBT, 57.6%; and CFT, 53.6%. All tests were negative for 100 tested sheep from Brucella-free flocks. The different results of bacteriological and immunological tests suggest the usefulness of developing indirect tests able to distinguish truly infected animals from those that have developed an immunological response.
A lipid extract with a composition similar to that of myelin was used to prepare liposomes and proteoliposomes containing the Folch-Lees proteolipid apoprotein. Freeze-fracture replicas of the proteoliposomes were prepared to demonstrate the presence of intramembrane protein particles in the fracture faces of the lipid bilayer. Experiments with 45CaCl2 showed that a steady calcium movement occurs across liposomal membranes, approaching equilibrium between intra- and extravesicular spaces. The most significant finding was that Mg-ATP, ATP analogues, and other nucleotides depressed significantly the calcium fluxes in proteoliposomes, having no effect on liposomes that lacked the proteolipid protein. It is suggested that this intrinsic protein, interacting with nucleotides and endogenous lipids, could be involved in the regulation of calcium levels in myelin by means of a conformational change mechanism. These observations could lead to implications concerning the pathophysiology of myelin.
BackgroundCardiovascular events (CVE) are an increasing cause of morbi-mortality for HIV patients. The antiretroviral therapy (ART), persistent immune activation, and life style are factors that can increase CVE for such patients. We performed a case-control study to evaluate the role of coinfections and immune markers associated with CVE.MethodsWe included patients under ART, with undetectable plasma viral load ≥12 months. Patients presenting any condition of risk for CVE were considered cases, and those without CVE risk conditions were controls. History of viral infections (Epstein–Barr virus, hepatitis C virus, hepatitis B virus, and cytomegalovirus), exposure to antiretroviral drugs, time since HIV diagnosis/under ART, and life style (demographics, weight, smoking, alcohol, and illicit drug use) were assessed. CD4/CD8 nadir and current counts, nadir and current CD4/CD8 ratio, immune activation markers (CD4CD38HLADR, CD8CD38HLADR), and serum levels of eight cytokines [IL-2, IL-4, IL-6, IL-10, tumoral necrosis factor-alpha (TNF-α), interferon gamma, macrophage inflammatory proteins 1 alpha, and interferon-inducing protein (IP-10)] were measured.ResultsTwo-thirds of patients were males. Cases (N = 106) were older (52.8 vs 49.5 years, p = 0.002), had higher levels of creatinine (0.97 vs 0.87 mg/dL, p = 0.002) and IL-6 (0.67 vs 0.52 pg/mL, p = 0.04) than controls (N = 114). There was no difference between groups regarding frequency of CD4CD39HLADR+ or CD8CD38HLADR+ cells. We found a significant correlation (all patients) between increased frequency of CD4CD38HLADR+ cells and levels of IP-10 (r = 0.171, p = 0.02) and TNF-α (r = 0.187, p = 0.01). Levels of IL-6 (r = 0.235, p = 0.02), TNF-α (r = 0.267, p = 0.01), and IP-10 (r = 0.205, p = 0.04) were correlated with CD4CD38HLADR+ cells, in controls. Higher frequency of CD4CD38HLADR+ cells was also correlated with levels of IP-10 (r = 0.271, p = 0.04) in patients presenting with arterial hypertension. Frequency of CD4CD38HLADR+ cells was negatively correlated with levels of IL-2 (r = −0.639, p = 0.01) and IL-6 (r = −0.0561, p = 0.03) in patients with hypercholesterolemia. No association was detected between viral infections or smoking/alcohol use and immune activation markers.ConclusionOur results indicate IL-6 levels are associated with increased CV risk. Activated CD4+ T cells were associated with increased levels of proinflammatory cytokines.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.