Chronic sleep loss disrupts blood–testis and blood–epididymis barriers,and reduces male fertility

Sleep loss increases blood–brain barrier permeability. As the blood–brain barrier and the blood–tissue barriers in the reproductive tract (blood–testis and blood–epididymis barriers) share common characteristics, we hypothesized that sleep restriction may also modify their barrier function. Previous reports showed that sleep loss decreased sperm viability and progressive fast mobility, which may be a consequence of altered blood–testis and blood–epididymis barrier. Therefore, we quantified changes in blood–testis and blood–epididymis barrier after sleep loss and related them to male fertility. Adult male Wistar rats were sleep restricted using the multiple‐platform technique in a protocol of 20 hr daily sleep deprivation plus 4 hr of sleep recovery in the home‐cage. At the 10th day, barrier permeability assays were performed with Na‐fluorescein, 10 kDa Cascade blue‐dextrans and Evans blue, and the expression of tight junction proteins, actin and androgen receptor was quantified. At the 10th day of sleep restriction and after sleep recovery days 1–7, males were placed with sexually receptive females, sexual behaviour was tested, and the percentage of pregnancies was calculated. Sleep restriction increased the barrier permeability to low‐ and high‐molecular‐weight tracers, and decreased the expression of tight junction proteins, actin and androgen receptor. Concomitantly, sleep restriction reduced the percentage of ejaculating males and the number of pregnancies. Sleep recovery for 2–3 days progressively re‐established fertility, as indicated by a higher percentage of ejaculating males and impregnated females. In conclusion, chronic sleep loss alters fertility concomitantly with the disruption of the blood–tissue barriers at the reproductive tract, the mechanism involves androgen signalling.     

Deriving bathymetry and water properties from hyperspectral imagery by spectral matching using a full radiative transfer model

ABSTRACT

Many existing techniques for estimating the optical properties of a body of water directly from a hyperspectral remote sensing spectrum are based on the idea of ‘spectral matching’ – that is, input parameters in a forward model are systematically varied until the measured and modelled spectra are sufficiently similar. This is usually done by using numerical optimization methods with a simplified forward model, or by precomputing a large library of spectra with a more realistic model, and then searching the library for the best match. In this letter, we show that is possible to combine the two approaches by using a full radiative transfer model in an optimization routine. We include results of running the algorithm on both simulated and measured data.     

An ultrastructural study of alkaline phosphatase activity in normal and neoplastic human salivary glands

Alkaline phosphatase activity of normal human parotid and submandibular glands and four benign mixed tumours of the parotid gland was investigated by ultrastructural cytochemistry in order to identify myoepithelial cells and the extent of their participation in the histogenesis of such tumours. The results indicated that myoepithelial cells in the normal salivary glands were negative for alkaline phosphatase activity and, therefore, enzyme localization as a marker for identification of such cells in mixed tumours was not reliable. Occasional neoplastic cells in the more glandular parts of the tumours displayed surface membrane associated alkaline phosphatase reactivity. In addition, the luminal microvilli of some neoplastic cells were positive for the enzyme, thereby suggesting a resorptive or absorptive function for cells which were formerly secretory in nature.     

Evaluation of silver methenamine method for nanoleakage

OBJECTIVES: The aim of this study was to evaluate nanoleakage patterns following silver methenamine staining of restorations bonded with a total-etch single bottle system, a self-etching primer system and a total-etch single bottle system after collagen depletion. METHODS: The dentin bonding systems used in this study were Prime and bond 2.1 (PB) and Clearfil SE Bond (CSEB). Cavities were made in grounded labial surfaces of 15 extracted bovine lower incisors, randomly divided into 3 Groups. Group 1 (PB), Group 2 (CSEB) and Group 3 (PB/SH) PB after collagen depletion with sodium hypochlorite (SH). The specimens were restored, sectioned and submitted to silver methenamine staining, polished and observed with low-vacuum back-scattered SEM. One way ANOVA and multiple-comparison Tukey's test were used for statistical analysis of the leakage scores. RESULTS: PB presented significantly greater silver deposition and a distinct pattern when compared to CSEB. No silver deposition was detected for PB after collagen depletion. SIGNIFICANCE: The dentine bonding systems tested were unable to prevent nanoleakage when used according to the manufacturers' instructions; however, CSEB presented a lower level of silver deposition. Collagen depletion prior to PB application may prevent nanoleakage occurrence in dentine walls. Silver methenamine staining may be a useful method for detection of nanoleakage in dentine when the collagen fibrils remain exposed within the hybrid layers.