The mechanisms for acquisition of iron by Haemophilus influenzae and their role in pathogenesis are not known. Heme and nonheme sources of iron were evaluated for their effect on growth of type b and nontypable strains of H. influenzae in an iron-restricted, defined medium. All 13 strains acquired iron from heme, hemoglobin, hemoglobin-haptoglobin, and heme-hemopexin. Among nonheme sources of p...

Introduction: Iron metabolism was found to be implicated in several cancers. Few epidemiologic studies; focusing on iron intake and lung cancer (LC), reported positive associations between heme iron and red meat. Based on estimates of iron contents in representative foods, we conducted the present study with the aim of analyzing dietary iron and its role on the incidence of LC in Uruguayan men,...

We used the Ussing chamber model to study heme iron absorption by rat duodenal mucosa. Heme iron was obtained by enzymic digestion of bovine haemoglobin and concentration of heme (HPH). Its uptake and mucosal transfer was compared to iron gluconate (Gluc), at 100 microM and 1 mM. At 100 microM iron uptake (Qtot), mucosal retention (Qm) and transfer across the mucosa (Qs) was similar for the two...

Helicobacter pylori chronically infects the gastric mucosa, where it can be found free in mucus, attached to cells, and intracellularly. H. pylori requires iron for growth, but the sources of iron used in vivo are unclear. In previous studies, the inability to culture H. pylori without serum made it difficult to determine which host iron sources might be used by H. pylori. Using iron-deficient,...

Mechanisms of superoxide.O2--generating systems on the pro-oxidant effect of iron from various sources were studied. Reaction mixtures were prepared with distilled water, oil emulsion, or meat homogenates. Free ionic iron (ferrous and ferric), ferritin and hemoglobin (Hb) were used as iron sources, and KO2 and xanthine oxidase (XOD) systems were used to produce .O2-. Thiobarbituric acid reactiv...

Leishmania chagasi, the cause of South American visceral leishmaniasis, requires iron for its growth. However, the extent to which different iron sources can be utilized by the parasite is not known. To address this question, we studied acquisition of iron from lactoferrin and transferrin by the extracellular promastigote form of L. chagasi during growth in vitro. A promastigote growth medium b...

Introduction: Iron metabolism was found to be implicated in several cancers. Few epidemiologic studies; focusing on iron intake and lung cancer (LC), reported positive associations between heme iron and red meat. Based on estimates of iron contents in representative foods, we conducted the present study with the aim of analyzing dietary iron and its role on the incidence of LC in Uruguayan men,...

Bioavailability of a single iron source is difficult to predict. It can vary considerably due to the enhancing or inhibitory effects of other food components on iron absorption and, especially for the less-available sources, it is strongly influenced by the physical characteristics of the iron compound itself. It is sometimes difficult for the food manufacturer or food scientist to interpret th...

Iron is a critical co-factor for several enzymes and is known to regulate gene expression in many pathogens. Streptococcus pneumoniae (pneumococcus) normally colonizes the upper respiratory mucosa, which is an iron-restricted environment. In contrast, during bacteremia available iron from heme and non-heme proteins potentially increases. In iron-depleted medium pneumococcal strain TIGR4 showed ...