Superoxide anion generation in human milk macrophages: opsonin-dependent versus opsonin-independent stimulation compared with blood monocytes

Water disinfection processes change the cytotoxicity of C60 fullerene: Reactions at the nano-bio interface

The environmental transformation of nanoparticles results in significant changes in their structure, properties, and toxicity, which are imperative for assessing their environmental impact and health risks. Little is known about the toxicity alteration of fullerene nanoparticles (C₆₀) after water disinfection processes considering their potential application in antimicrobial control in water treatment ultimately ending in sewage treatment plants. We showed that C₆₀ aggregates (nC₆₀) were converted to more oxidized forms via commonly used water disinfection processes (i.e., phototransformation and photochlorination treatment). The light-irradiated nanoparticles (UV_nC₆₀) exhibited mitigated cytotoxicity relative to nC₆₀, whereas photochlorinated nC₆₀ (UV/Cl_nC₆₀) showed an exacerbated outcome. We revealed a distinct toxic mechanism occurring at the nano-bio interface, for which electrons were shuttled by C₆₀ nanoparticles from membrane-bound NADPH oxidase to extracellular molecular oxygen, resulting in the production of various extracellular reactive oxygen species (ROS). UV/Cl_nC₆₀ showed the highest electron-shuttling activity due to its high carbonyl content, and more than 2.4-fold higher level of extracellular hydroxyl radicals were detected relative to that in untreated cells. Although UV_nC₆₀ possessed a somewhat higher carbonyl content than nC₆₀, it showed a weaker adhesion to the cell membrane, which compromised the electron-transfer process. The intrinsic ROS generation/quenching capabilities and oxidative potentials of the various nanoparticles were also systematically compared. Overall, this report highlights the importance of understanding environmental transformations in risk assessment and uncovers an overlooked mechanism through which nC₆₀/derivatives can modulate the electron transfer process at the nano-bio interface via acting as electron shuttles.

Host factors in amniotic fluid and breast milk that contribute to gut maturation

The gut represents a complex organ system with regional differences, which reflect selective digestive and absorptive functions that change constantly in response to bodily requirements and the outside milieu. As a barrier to the external environment, gut epithelium must be renewed rapidly and repeatedly. Growth and renewal of gut epithelial cells is dependent on controlled cell stimulation and proliferation by a number of signaling processes and agents, including gut peptides-both endogenous and exogenous sources. This cascade of events begins during fetal development; with the ingestion of amniotic fluid, this process is enhanced and continued during infancy and early childhood through the ingestion of human milk. Events influenced by amniotic fluid during fetal development and those influenced by human milk that unfold after birth and early childhood to render the gut mature are presented.

Effect of fetal bovine serum and heat-inactivated fetal bovine serum on microbial cell wall-induced expression of procoagulant activity by equine and canine mononuclear cells in vitro

OBJECTIVE

To determine the effect of fetal bovine serum (FBS) and heat-inactivated FBS (HI-FBS) on lipopolysaccharide (LPS)- and zymosan-induced procoagulant activity of equine and canine mononuclear cells.

SAMPLE POPULATION

Mononuclear cells from 18 horses and 3 dogs.

PROCEDURES

Cells were incubated with various concentrations of FBS, HI-FBS, LPS, zymosan, polymyxin B, and anti-LPS-binding protein monoclonal antibody or combinations of these constituents. A 1 stage recalcification assay was used to determine procoagulant activity.

RESULTS

Addition of FBS to media significantly increased procoagulant activity; equine and canine cells were stimulated by 1% and 10% FBS, respectively. Coincubation of cells with FBS and polymyxin B did not reduce this effect, suggesting that the response was not attributable to LPS contamination. Addition of HI-FBS to media did not stimulate procoagulant activity of equine or canine cells, and the sensitivity of the equine cells to LPS was significantly increased by HI-FBS. This increased LPS sensitivity was reduced 40% with monoclonal antibody directed against human recombinant LPS-binding protein. Increasing concentrations of HIFBS significantly increased LPS- and zymosan-induced procoagulant activity of canine cells.

CONCLUSION AND CLINICAL RELEVANCE

Procoagulant activity production in equine and canine mononuclear cells was significantly increased by addition of FBS, whereas heat inactivation of FBS eliminated this effect. Heat inactivation did not eliminate the function of serum proteins involved in enhancement of LPS and zymosan-induced procoagulant activity. Results suggest that HI-FBS can be used as a source of serum proteins that increase the sensitivity of mononuclear cells to bacterial and yeast cell wall components.

[Current topics in pediatric nutrition]

As main current topics in pediatric nutrition we have considered the results of the continuing research on the long term consequences of fetal malnutrition and intra-uterine growth retardation with the concept of metabolic imprinting leading to chronic disease in adulthood, the progresses of knowledge in the fields of iron metabolism and regulatory mechanisms of satiety, hunger and energetic balance, a better determination of recommended docosahexanoic and arachidonic acids intake in the first months of life for premature and term infants, and the studies on probiotics and prebiotics utilization for preventive and curative purposes. The concerns about vitamin D insufficiency in France have markedly decreased with the generalization ten years ago of cholecalciferol supplementation of infant formula, and more recently the authorization of dairy products supplementation. On the contrary the problem of iron deficiency in young children remains, as well as two major nutritional concerns: the very low percentage of breast-fed infants and the dramatic increase of childhood obesity which affects presently 14% of 10 year old children versus 5% in 1980.