Endothelial cells regulate p53-dependent apoptosis of neural progenitors after irradiation

Endothelial cells represent an important component of the neurogenic niche and may regulate self-renewal and differentiation of neural progenitor cells (NPCs). Whether they have a role in determining the apoptotic fate of NPCs after stress or injury is unclear. NPCs are known to undergo p53-dependent apoptosis after ionizing radiation, whereas endothelial cell apoptosis after irradiation is dependent on membrane acid sphingomyelinase (ASMase) and is abrogated in sphingomyelin phosphodiesterase 1 (smpd1)- (gene that encodes ASMase) deficient mice. Here we found that p53-dependent apoptosis of NPCs in vivo after irradiation was inhibited in smpd1-deficient mice. NPCs cultured from mice, wild type (+/+) or knockout (−/−), of the smpd1 gene, however, demonstrated no difference in apoptosis radiosensitivity. NPCs transplanted into the hippocampus of smpd1−/− mice were protected against apoptosis after irradiation compared with those transplanted into smpd1+/+ mice. Intravenous administration of basic fibroblast growth factor, which does not cross the blood–brain barrier, known to protect endothelial cells against apoptosis after irradiation also attenuated the apoptotic response of NPCs. These findings provide evidence that endothelial cells may regulate p53-dependent apoptosis of NPCs after genotoxic stress and add support to an important role of endothelial cells in regulating apoptosis of NPCs after injury or in disease

The Probable Cell of Origin of NF1- and PDGF-Driven Glioblastomas

Primary glioblastomas are subdivided into several molecular subtypes. There is an ongoing debate over the cell of origin for these tumor types where some suggest a progenitor while others argue for a stem cell origin. Even within the same molecular subgroup, and using lineage tracing in mouse models, different groups have reached different conclusions. We addressed this problem from a combined mathematical modeling and experimental standpoint. We designed a novel mathematical framework to identify the most likely cells of origin of two glioma subtypes. Our mathematical model of the unperturbed in vivo system predicts that if a genetic event contributing to tumor initiation imparts symmetric self-renewing cell division (such as PDGF overexpression), then the cell of origin is a transit amplifier. Otherwise, the initiating mutations arise in stem cells. The mathematical framework was validated with the RCAS/tv-a system of somatic gene transfer in mice. We demonstrated that PDGF-induced gliomas can be derived from GFAP-expressing cells of the subventricular zone or the cortex (reactive astrocytes), thus validating the predictions of our mathematical model. This interdisciplinary approach allowed us to determine the likelihood that individual cell types serve as the cells of origin of gliomas in an unperturbed system

Potential use of high-temperature and low-temperature steam treatment, sodium hydroxide and an enzyme mixture for improving the nutritional value of sugarcane pith

The effectiveness of different treatment methods to improve the nutritional value of the sugarcane by-products (pith or bagasse) has been evaluated. The treatment methods included a high-pressure steam treatment (HPST; 19 bar, 3 min), treating the products with sodium hydroxide, sulphuric acid plus an enzyme mixture, or low-temperature steam treatment (LTST) under different conditions. Gas production (GP), two-step in vitro digestibility (IVD) and in situ degradability (ISD) techniques were used to monitor the effectiveness of the treatments. HPST resulted in a significant increased in the total soluble sugar (TSS) content of unsteamed pith (USP), 20 vs. 123.75 mg/100 mL. Except for the enzyme treatment, the other treatments led to a significant improvement in the nutritional value of sugarcane by-products, as measured by the IVD method. LTST resulted in an increase in potential GP (B) at higher temperature, reaction time and amount of acid. The highest potential GP (110.92 mL/300 mg DM) was achieved under the conditions, 134 °C, 18 g acid/kg DM, 120 min, and the lowest (72.4 mL/300 mg DM) under the conditions, 121 °C, no acid, 40 min. In situ dry matter degradability (ISDMD) was unaffected by LTST. Dry matter digestibility results indicated that the optimal treatments for treating pith were HPST and NaOH, but that enzymes were ineffective. Furthermore, considering treatment cost (creating high-pressure are more expensive than low temperature treatments), potential environmental health problems and the relative improvement in the nutritional value of pith achieved by the LTST + acid method, compared to the HPST method (as measured using GP), these results suggested that the methods based on the use of LTST and acid (especially under harsher conditions), have the best potential to improve the nutritive value of sugarcane by-products.Keywords: Saccharum officinarum, steam, bagasse, raw or unsteam-treated pit

Potential use of high-temperature and low-temperature steam treatment, sodium hydroxide and an enzyme mixture for improving the nutritional value of sugarcane pith

________________________________________________________________________________ Abstract The effectiveness of different treatment methods to improve the nutritional value of the sugarcane byproducts (pith or bagasse) has been evaluated. The treatment methods included a high-pressure steam treatment (HPST; 19 bar, 3 min), treating the products with sodium hydroxide, sulphuric acid plus an enzyme mixture, or low-temperature steam treatment (LTST) under different conditions. Gas production (GP), two-step in vitro digestibility (IVD) and in situ degradability (ISD) techniques were used to monitor the effectiveness of the treatments. HPST resulted in a significant increased in the total soluble sugar (TSS) content of unsteamed pith (USP), 20 vs. 123.75 mg/100 mL. Except for the enzyme treatment, the other treatments led to a significant improvement in the nutritional value of sugarcane by-products, as measured by the IVD method. LTST resulted in an increase in potential GP (B) at higher temperature, reaction time and amount of acid. The highest potential GP (110.92 mL/300 mg DM) was achieved under the conditions, 134 °C, 18 g acid/kg DM, 120 min, and the lowest (72.4 mL/300 mg DM) under the conditions, 121 °C, no acid, 40 min. In situ dry matter degradability (ISDMD) was unaffected by LTST. Dry matter digestibility results indicated that the optimal treatments for treating pith were HPST and NaOH, but that enzymes were ineffective. Furthermore, considering treatment cost (creating high-pressure are more expensive than low temperature treatments), potential environmental health problems and the relative improvement in the nutritional value of pith achieved by the LTST + acid method, compared to the HPST method (as measured using GP), these results suggested that the methods based on the use of LTST and acid (especially under harsher conditions), have the best potential to improve the nutritive value of sugarcane by-products. _______________________________________________________________________________

Seasonal Variations in Semen Characteristics in Arabic Rams

The aim of this study was to evaluate the seasonal variations in semen characteristics in Arabic rams. 8 adult Arabic rams at the age of 2-3 years were used for this research. Semen was collected with electro ejaculator every 15 days for a period of 6 months (3 months of in breeding season and 3 months of non breeding season). Semen samples of these rams were subjected to the parameters including semen volume, sperm motility, sperm concentration, abnormal and live sperm percentage. Semen quality difference between breeding and non breeding seasons was significant. Semen volume, sperm motility, percent of live sperm, the percentage of abnormal sperm and sperm concentration determined in breeding and non breeding seasons had significant differences. Therefore, better progressive motility of sperm, sperm concentration, percent of live sperm and low percentage of abnormal sperm clearly explained high fertility potential of male in breeding season when compared with non breeding season. In conclusion, this study indicated that sexual performance of Arabic rams completely dependent on season