Role of cholesterol, DOTAP, and DPPC in prostasome/spermatozoa interaction and fusion.

Prostasomes are membranous vesicles present in ejaculated human semen. They are very rich in cholesterol and can interact with spermatozoa. Their physiological roles are still under study.

Cytosolic calcium levels in spermatozoa are modulated differently in healthy subjects and patients with varicocele.

Objective: To study parameters connected to fertility in the semen of patients with varicocele.

Design: We examine the ability of spermatozoa obtained from patients with varicocele to respond with an increase of cytosolic Ca2+ ([Ca2+]i) to some stimuli that are connected with spermatozoa activation.

Setting: An academic research environment.

Antagonism between olive oil phenolics and nitric oxide on lymphomonocyte cytosolic calcium.

Some biological actions of olive oil phenolics (inhibition of platelet aggregation, decrease of LDL-oxidation, inhibition of bacterial growth and hypertensive action) have been attributed to NOS stimulation in endothelial cells through an increase of cytosolic calcium, notwithstanding the scavenging activity of phenolics on NO and superoxide. In this paper, we determine the concentration of cytosolic calcium in human lymphomonocytes incubated with high concentrations of NO-donors (CysNO) and we evaluate the effects of olive oil phenolics on this parameter. CysNO induces a marked decrease of cytosolic calcium; both olive oil phenolics oppose this action of CysNO.

Activity of olive oil phenols on lymphomonocyte cytosolic calcium.

Phenols, present in the Mediterranean diet, have antioxidant properties and are free radical scavengers; however, the molecular mechanisms of their beneficial effects are not yet fully understood. The level of cytosolic calcium ([Ca2+]i) is an important signal also in nonexcitable cells, including immune cells, and regulates fundamental processes. In this paper, we determine [Ca2+]i in human lymphomonocytes incubated with two olive oil phenols: 3,4-(dihydroxyphenyl)ethanol and p-(hydroxyphenyl)ethanol.

Fusion of prostasomes to human spermatozoa stimulates the acrosome reaction.

Objective: To determine the effect of the fusion of prostasomes to spermatozoa on the acrosome reaction.

Design: In vitro study of human spermatozoa.

Setting: Healthy volunteers in an academic research environment.

Nitric oxide and fusion with prostasomes increase cytosolic calcium in progesterone-stimulated sperm.

Spermatozoa must undergo a number of reactions before they are able to fertilize the oocyte. Among these is the acrosome reaction, which is related to an increase in cytosolic Ca2+ concentration ([Ca2+]i). It has been reported in the literature that progesterone may achieve this effect through the intervention of extragenomic receptors.