Rapid changes in chimpanzee (Pan troglodytes) urinary cortisol excretion

Behavioral endocrinologists are aware that many hormones exhibit a diurnal rhythm, and attempt to correct for this pattern by collecting physiological samples only during specified time windows of varying lengths. In studies utilizing urinary measures of hormone levels, this window often spans 2 h or longer. In this study, we compared chimpanzee urinary cortisol levels in sample pairs collected within 1 h of each other in an attempt to validate the use of a time window for sample collection. Chimpanzees were housed at the University of Louisiana New Iberia Research Center and trained to urinate into a paper cup on command; a total of 41 sample pairs were included in this analysis. We found that mean cortisol levels in the two sets of samples, collected within 1 h or less of each other, were significantly different; the mean cortisol level of the first set of samples was significantly higher than that of the second set. This hormone's diurnal pattern of secretion accounts for this significant decrease over a very short time period. We conclude that collection methodologies involving time windows of 1 h or longer need to take into account such rapid changes in levels of excreted hormone. We advocate the use of methodological and statistical corrections to decrease the impact of short-term fluctuations in urinary cortisol.     

Seasonal variations of cellular stress response in the heart and gastrocnemius muscle of the water frog (Pelophylax ridibundus)

The present study aimed to investigate the seasonal cellular stress response in the heart and the gastrocnemius muscle of the amphibian Pelophylax ridibundus (former name Rana ridibunda) during an 8 month acclimatization period in the field. Processes studied included heat shock protein expression and protein kinase activation. The cellular stress response was addressed through the expression of Hsp70 and Hsp90 and the phosphorylation of stress-activated protein kinases and particularly p38 mitogen-activated protein kinase (p38 MAPK), the extracellular signal-regulated kinases (ERK-1/2) and c-Jun N-terminal kinases (JNK1/2/3). Due to a general metabolic depression during winter hibernation, the induction of Hsp70 and Hsp90 and the phosphorylation of p38 MAPK, JNKs and ERKs are retained at low levels of expression in the examined tissues of P. ridibundus. Recovery from hibernation induces increased levels of the specific proteins, probably providing stamina to the animals during their arousal.     

Succinic acid fermentation in a stationary-basket bioreactor with a packed bed of immobilized Actinobacillus succinogenes: 1. Influence of internal diffusion on substrate mass transfer and consumption rate

This paper is dedicated to the study on external and internal mass transfers of glucose for succinic fermentation under substrate and product inhibitions using a bioreactor with a stationary basket bed of immobilized Actinobacillus succinogenes cells. By means of the substrate mass balance for a single particle of biocatalysts, considering the Jerusalimsky kinetic model including both inhibitory effects, specific mathematical expressions have been developed for describing the profiles of the substrate concentrations and mass flows in the outer and inner regions of biocatalyst particles, as well as for estimating the influence of internal diffusion on glucose consumption rate. The results indicated that very low values of internal mass flow could be reached in the particles center. The corresponding region was considered biologically inactive, with its extent varying from 0.24% to 44% from the overall volume of each biocatalyst. By immobilization of bacterial cells and use of a basket bed, the rate of glucose consumption is reduced up to 200 times compared with the succinic fermentation system containing free cells.     

Investigation of pulsed electromagnetic field as a novel organic pre-sowing method on germination and initial growth stages of cotton

Two different pre-sowing techniques have been investigated for their influence in an important industrial plant, namely cotton. Priming methods are very useful for agricultural practices because they improve crop seedling establishment, especially when environmental conditions are not optimum. Pulsed electromagnetic fields have been found to promote germination and improve early growth characteristics of cotton seedlings. Such priming techniques are especially valuable in organic cultivation, where chemical compounds are prohibited. PEG treatment showed an enhancement in some measurements, however in some cases the results were not statistically different compared to control plants. In addition, PEG treatment is a sophisticated method that is far from agricultural practices and farmers. In this research, two different ages of seeds were used (1- and 2-year-old) in order to investigate the promotory effects of priming techniques. Magnetic field treatment of 15?min was found to stimulate germination percentage and to promote seeds, resulting in 85% higher values than control seeds under real field conditions. Furthermore, seeds that were treated with magnetic field performed better in terms of early-stage measurements and root characteristics.     

Combined metformin-salicylate treatment provides improved anti-tumor activity and enhanced radiotherapy response in prostate cancer; drug synergy at clinically relevant doses

BackgroundThere is need for well-tolerated therapies for prostate cancer (PrCa) secondary prevention and to improve response to radiotherapy (RT). The anti-diabetic agent metformin (MET) and the aspirin metabolite salicylate (SAL) are shown to activate AMP-activated protein kinase (AMPK), suppress de novo lipogenesis (DNL), the mammalian target of rapamycin (mTOR) pathway and reduce PrCa proliferation in-vitro. The purpose of this study was to examine whether combined MET+SAL treatment could provide enhanced PrCa tumor suppression and improve response to RT.MethodsAndrogen-sensitive (22RV1) and resistant (PC3, DU-145) PrCa cells and PC3 xenografts were used to examine whether combined treatment with MET+SAL can provide improved anti-tumor activity compared to each agent alone in non-irradiated and irradiated PrCa cells and tumors. Mechanisms of action were investigated with analysis of signaling events, mitochondria respiration and DNL activity assays.ResultsWe observed that PrCa cells are resistant to clinically relevant doses of MET. Combined MET + SAL treatment provides synergistic anti-proliferative activity at clinically relevant doses and enhances the anti-proliferative effects of RT. This was associated with suppression of oxygen consumption rate (OCR), activation of AMPK, suppression of acetyl-CoA carboxylase (ACC)-DNL and mTOR-p70^s6k/4EBP1 and HIF1α pathways. MET + SAL reduced tumor growth in non-irradiated tumors and enhanced the effects of RT.ConclusionMET+SAL treatment suppresses PrCa cell proliferation and tumor growth and enhances responses to RT at clinically relevant doses. Since MET and SAL are safe, widely-used and inexpensive agents, these data support the investigation of MET+SAL in PrCa clinical trials alone and in combination with RT.     

Specific gravity as an alternative to creatinine for estimating urine concentration in captive and wild chimpanzee (Pan troglodytes) Samples

The measurement of hormones in urine has become a widely used technique in primatology. Because urine concentration varies according to fluid intake, concentration must be measured in each sample collected, and hormone values are always expressed per unit of concentration. Traditionally, creatinine has been used as a concentration index, but some studies in humans have shown that creatinine varies among populations and even within and between individuals within a population, and that it begins to degrade after just one freeze-thaw cycle. In addition, creatinine measurement is relatively time-consuming and expensive and creates hazardous waste. In this study, we tested the hypothesis that specific gravity, or the ratio of the density of a sample to that of water, is highly correlated with creatinine measurement in urine samples collected from captive chimpanzees at the New Iberia Research Center in Louisiana and wild chimpanzees at the Ngogo study site in the Kibale National Park, Uganda. We found that specific gravity and creatinine were highly correlated in both captive (N=124) and wild (N=13) chimpanzee samples, and that specific gravity measurement was robust to actual and simulated transport conditions and repeated freeze-thaw cycles. We recommend that researchers consider specific gravity measurement as a preferable alternative to creatinine measurement in their studies of primate endocrinology.