Coagulation and proteolysis of high-protein milks in the gastric environment.

Gastric digestion of 2 commercial ultrafiltered milks and milk enriched with skim milk powder (to simulate concentration by reverse osmosis) was investigated and compared with the digestion of nonconcentrated milk. Curd formation and proteolysis of high-protein milks in simulated gastric conditions were studied using oscillatory rheology, extrusion testing, and gel electrophoresis. The presence of pepsin in the gastric fluid triggered coagulation at pH >6 and the elastic modulus of gels from high-protein milks was ~5 times larger than the gel from reference milk.

Effect of emulsifiers on linseed oil emulsion structure, lipolysis and oxidation during digestion.

Health benefits have been associated with the consumption of omega-3 polyunsaturated fatty acids (PUFA). Linseed oil is rich in long chain omega-3 PUFA, but can generate toxic compounds due to its high susceptibility to oxidation. The nature of the emulsifier can affect both lipolysis and oxidation during digestion since these phenomena occur at the oil-water interface.

Gonad differentiation toward ovary.

Gonad differentiation depends on a set of cellular and hormonal signals interacting in a specific order, with very precise windows of action, to contribute to the establishment of the genital tract and a male or female phenotype. Research initially focused on the stages of gonad differentiation toward testis, in particular following the identification in 1990 of the SRY factor on chromosome Y. The mechanisms involved in gonad differentiation toward ovary took longer to identify.

Antioxidant activity of milk and polyphenol-rich beverages during simulated gastrointestinal digestion of linseed oil emulsions.

Polyunsaturated fatty acids (PUFA) are associated with health benefits. However, high PUFA intake increases the risk of lipid oxidation and formation of potentially toxic lipid oxidation species. The objective of this study was to determine the antioxidant activity of milk fractions (whole milk, skim milk, acid whey, ultrafiltration (UF) permeate) and polyphenol-rich beverages (green tea, grape juice) during simulated gastrointestinal digestion.

Effect of milk proteins and food-grade surfactants on oxidation of linseed oil-in-water emulsions during in vitro digestion.

Health benefits are associated with polyunsaturated fatty acids, but their sensitivity to oxidation may generate toxic oxidation species. The objective of this study was to compare the effect of milk proteins (casein, whey protein) and surfactants (Citrem, Tween 20) on the in vitro digestion and oxidation of linseed oil emulsions. The emulsion produced with Tween 20 resisted coalescence in the gastric phase and showed the highest concentrations of free fatty acids and reactive carbonyl compounds in the intestinal digestion phase.

[Semen quality and fertility: the role of the environment and health].

Sperm quality appears to be degrading over the past 40 years. Nowadays, more than 35 % of causes of male infertility are still idiopathic. More and more studies have suggested an impact of environment on sperm quality, essentially through epigenetic and hormonal changes.

Autocrine actions of prolactin contribute to the regulation of lactotroph function in vivo.

Prolactin (PRL), whose principal role is regulation of lactation, is mainly synthesized and secreted by lactotroph anterior pituitary cells. Its signaling is exerted via a transmembrane PRL receptor (PRLR) expressed in a wide variety of tissues, including the anterior pituitary. Dopamine, which is secreted by tuberoinfundibular hypothalamic neurons, is the major inhibitory regulator of prolactin secretion.

Natural and molecular history of prolactinoma: insights from a mouse model.

Lactotroph adenoma, also called prolactinoma, is the most common pituitary tumor but little is known about its pathogenesis. Mouse models of prolactinoma can be useful to better understand molecular mechanisms involved in abnormal lactotroph cell proliferation and secretion. We have previously developed a prolactin receptor deficient ( ) mouse, which develops prolactinoma.

Influence of dairy matrices on nutrient release in a simulated gastrointestinal environment.

The objective of this study was to compare the kinetics of the release of nutrients (peptides and fatty acids) from different dairy matrices (milks, yogurts, and cheeses) in a simulated gastrointestinal environment. Prior to processing, different heat and homogenization treatments were applied to milks, and different drainage pH levels were used to control calcium concentration in cheeses. The dairy matrices were then subjected to simulated digestion.

Antioxidant activity and nutrient release from polyphenol-enriched cheese in a simulated gastrointestinal environment.

Green tea polyphenols are recognized for their antioxidant properties and their effects on lipid digestion kinetics. Polyphenols are sensitive to degradation in the intestinal environment. Interactions with dairy proteins could modulate the stability and biological activity of polyphenols during digestion.

Interaction of green tea polyphenols with dairy matrices in a simulated gastrointestinal environment.

The consumption of polyphenols in green tea has been associated with beneficial health effects. Although polyphenols are unstable in the intestinal environment, they may be protected by interactions with dairy proteins during digestion. The objectives of this study were to evaluate the effect of a green tea extract on the digestibility of different dairy matrices and to monitor the antioxidant activity of these matrices with or without the green tea extract during digestion in a simulated gastrointestinal environment.

Congenital hypogonadotropic hypogonadism and Kallmann syndrome as models for studying hormonal regulation of human testicular endocrine functions.

Men with Kallmann syndrome (KS) and those with congenital isolated hypogonadotropic hypogonadism with normal olfaction share a chronic, usually profound deficit, in FSH and LH, the two pituitary gonadotropins. Many studies indicate that this gonadotropin deficiency is already present during fetal life, thus explaining the micropenis, cryptorchidism and marked testicular hypotrophy already present at birth. In addition, neonatal activation of gonadotropin secretion is compromised in boys with severe CHH/Kallmann, preventing the first phase of postnatal testicular activation.

Influence of cheese matrix on lipid digestion in a simulated gastro-intestinal environment.

Foods are complex nutrient assemblies which are subjected to various industrial processes that can influence their nutritional value. The food matrix acts as a nutrient-release regulator, and further understanding of its behavior during digestion is essential. The objective of this study was to compare the kinetics of matrix degradation and fatty acids release for different cheeses in a gastro-intestinal environment.

Butter making from caprine creams: effect of washing treatment on phospholipids and milk fat globule membrane proteins distribution.

A washing treatment was applied to caprine cream before churning in order to improve phospholipids and MFGM protein purification from buttermilk and butter serum. Cream obtained from a first separation was diluted with water and separated a second time using pilot plant equipment. Regular and washed creams were churned to produce buttermilk and butter, from which butter serum was extracted.