Nicotinamide phosphoribosyltransferase production in human spermatozoa is influenced by maturation stage.

High amounts of nicotinamide phosphoribosyltransferase (NAMPT) were found in human seminal plasma. This enzyme influences energy metabolism and apoptosis and is essential for the regulation of cellular nicotinamide adenine dinucleotide (NAD)+ levels in somatic cells. NAD+ is required as a co-substrate for dehydrogenases, which are potentially important for spermatogenesis. The functional significance of intra- and extracellular NAMPT in human reproduction, however, has not been defined yet. The objectives of the study were therefore to determine NAMPT protein expression in human spermatozoa and testes, the secretion of NAMPT by spermatozoa depending on their maturation stage and the impact of NAMPT enzymatic function on sperm viability, motility, fertilisation capacity and induction of apoptosis. Firstly, we detected NAMPT protein in different cell types of human testes. NAMPT protein was also detected in spermatozoa, with significantly higher amounts in immature than in mature ejaculated spermatozoa. Additionally, NAD+ levels were significantly higher in immature than in mature spermatozoa. Secondly, NAMPT was released into the supernatant of human spermatozoa, with significantly higher NAMPT levels in supernatant of immature spermatozoa compared with mature cells. Finally, the specific inhibition of the enzyme by FK866 did not influence motility, capacitation or apoptosis signalling. In summary, NAMPT is produced in human spermatozoa in a maturation-dependent manner.

Effects of a short-term reduction in brain serotonin synthesis on the availability of the soluble leptin receptor in healthy women.

Serotonin (5-HT) and the hormone leptin have been linked to the underlying neurobiology of appetite regulation with evidence coming from animal and cellular research, but direct evidence linking these two pathways in humans is lacking. We examined the effects of reduced brain 5-HT synthesis due to acute tryptophan depletion (ATD) on levels of soluble leptin receptor (sOb-R), the main high-affinity leptin binding protein, in healthy adults using an exploratory approach. Women, but not men, showed reduced sOb-R concentrations after ATD administration. With females showing reduced baseline levels of central 5-HT synthesis compared to males diminished brain 5-HT synthesis affected the leptin axis through the sOb-R in females, thereby potentially influencing their vulnerability to dysfunctional appetite regulation and co-morbid mood symptoms.

Multi-biochemical test system for distinguishing enteric and other gram-negative bacilli.

A multi-biochemical test system consisting of nine tests, entitled Enterotube, was evaluated in parallel with conventional tests to determine its value in the identification of enteric and certain other gram-negative bacilli. The 242 bacterial strains studied were from a variety of pathological specimens and from our culture collection. When the results with individual tests represented in both test systems were compared, no discrepancies were noted in the indole test, and one discrepancy was recorded for dextrose. In 7 of 242 hydrogen sulfide tests, 3 of 242 phenylalanine tests, 22 of 242 urease tests, 15 of 242 dulcitol tests, 12 of 242 lactose tests, 27 of 217 lysine decarboxylase tests, and 5 of 242 citrate tests, the Enterotube results were contrary to those obtained with conventional methods. The lysine decarboxylase test in the Enterotube posed a problem of interpretation and readability and is not an acceptable alternative to the conventional methods. Fifteen of the strains studied were incorrectly identified by the Enterotube system and four could not be differentiated from other closely related strains. Salmonella could be identified as to group, whereas Shigella strains were frequently misidentified as Escherichia. The Enterotube method is simple and convenient, and all media are inoculated at once from a single colony.