Objective-To determine the effect of ranitidine on gastric emptying in horses. Animals-11 adult horses. Procedures-In vitro, isolated muscle strips from the pyloric antrum and duodenum of 5 horses were suspended in baths and attached to isometric force transducers. Once stable spontaneous contractions were observed, ranitidine or diluent was added at cumulative increasing concentrations. Isometric stress responses were compared. In vivo, 6 horses were assigned to a group in a prospective randomized crossover study design with a wash-out period of 2 weeks between trials. Ranitidine (2.2 mg/kg) or saline (0.9% NaCl) solution was administered IV, and 15 minutes later, acetaminophen (20 mg/kg), diluted in 400 mL of water, was administered via nasogastric tube to evaluate the liquid phase of gastric emptying. Serum acetaminophen concentration was measured at several time points for 3 hours by use of liquid chromatography tandem mass spectrometry. Frequency of defecation was recorded during the 3 hours of the study. Results-Ranitidine increased the contractile activity of the pyloric antrum smooth muscle at a concentration of 10(4) M. No significant effect of ranitidine on plasma kinetics of acetaminophen was identified. Frequency of defecation did not differ between groups. Conclusions and Clinical Relevance-Ranitidine did increase gastric motility in vitro, but no effect on liquid phase gastric emptying was identified in healthy horses by use of the acetaminophen absorption model. Results do not support the use of ranitidine to promote gastric emptying. 相似文献
Cadaveric material has long been used to teach anatomy and more recently to train students in clinical skills. The aim of this study was to develop a systematic approach to compare the impact of four embalming solutions on the tissues of human cadavers. To this end, a formalin‐based solution, Thiel, Genelyn and Imperial College London soft‐preservation (ICL‐SP) solution were compared. The effect of these chemicals on the properties of the tissue was assessed by measuring the range of motion (ROM) of joints and measuring the dimensions of different structures on computed tomography (CT) images before and after embalming. The mean changes in the ratio (angle to ROM) differed statistically between embalming methods (Welch Statistic 3,1.672 = 67.213, p = 0.026). Thiel embalmed cadavers showed an increase in range of motion while ICL‐SP cadavers remained relatively the same. Genelyn and formalin embalmed cadavers registered a notable decrease in range of motion. Furthermore, investigation into the impact of the embalming chemicals on the dimensions of internal organs and vessels revealed that Thiel embalming technique leads to a decrease in the dimension of the cardiovascular system alone while formalin‐based solutions maintain the shape of the organs and vessels investigated. Our findings suggest that the joints of cadavers’ embalmed using ICL‐SP technique may faithfully mimic that of unembalmed cadavers and that formalin is necessary to retain shape and size of the organs and vessels investigated in this study. Despite this, a study with larger numbers of cadavers is required to confirm these findings. 相似文献
Digestive alkaline proteinases from golden grey mullet (Liza aurata) were extracted and characterized. The crude alkaline protease showed optimum activity at pH 8.0 and 60°C, and it was highly stable over a wide range of pH from 4.0 to 10.0, retaining more than 80% activity after incubation for 1 h at 4°C. The alkaline proteases showed extreme stability toward nonionic and anionic surfactants after preincubation for 1 h at 25°C and relative stability toward oxidizing agents. Additionally, the crude enzyme showed excellent stability and compatibility with various solid and liquid detergents. Further, proteases from golden grey mullet viscera were found to be effective in the deproteinization of shrimp wastes. The protein removal after 3 h at 45°C with an enzyme/substrate (E/S) ratio of 10 U/mg protein was about 76%. The golden grey mullet proteases were also shown to be efficient in the production of antioxidant protein hydrolysate. 相似文献
This study was carried out over three successive years (2003–2004–2005) in the southern Mediterranean region of Europe. Soybean plants were subjected to well-watered and water-stress conditions, and three levels of ozone (zero, low and high) in open top chambers (OTC) during the growing seasons.
The paper has four objectives: (i) to reproduce in OTCs the ozone concentrations actually observed in the field; (ii) to analyze the effect of ozone on well-watered crops by comparing a “control” (OTC ozone filtered treatment) with two ozone levels (at the end of the soybean growing seasons accumulated AOT40 values were 3400 and 9000 ppb h for low and high ozone treatments, respectively); observations were carried out both at leaf scale (stomatal conductance) and at canopy scale (determination of daily evapotranspiration, AET); (iii) to take into consideration the effect of drought, where the leaf and canopy scale observations were also implemented on water-stressed crops; and (iv) to analyze and verify the reliability of the ozone exposure–plant response relationship.
In well-watered conditions, an increase in ozone concentration levels reduced stomatal conductance and AET. Reductions in AET were 14% and 28% at low and high ozone levels, respectively, as compared to the control treatment. Hence, the results of daily AET were consistent with stomatal conductance results.
In water stress conditions, on the contrary, an increase in ozone had no effect on stomatal conductance and AET.
During the 3-year study, significant relationships were found between AOT40 and relative (low or high to control ozone treatment) values of stomatal conductance and AET in well-watered conditions. The reliability observed for these relationships suggest that they will be useful in soybean growth and yield-prediction models. 相似文献
Selenium (Se) is a contaminant of concern in environments affected by discharges from smelting and coal-burning industries. Experiments hate been performed to investigate the phase associations of selenium in contaminated sediments under a range of controlled redox conditions. In this study, Se sediment associations were examined using the BCR sequential extraction technique after stabilisation at different redox states. It was shown that although most of the sediment-bound Se is associated with the operationally-defined “organic sulfide” fraction, as the measured redox potential of the system is increased. more Se moves into the “exchangeable” and “iron manganese oxy hydroxide” fractions. In these fractions. contaminants can be expected to be more bioavailable. As the mass of Se absorbed to sediments is typically at least an order of magnitude higher than the mass dissolved in porewaters. significant Se exposure may result from oxidative shifts in Se associations. 相似文献
Physical and flow properties of proteins can provide information necessary for the optimal design of unit processes and quality control of the manufacturing process and final products. Therefore, the purpose of this investigation was to characterize the rheological behavior of a whey protein isolate (WPI) (BiPRO) dispersion as a function of pH and protein concentration. A rotational viscometer was used to determine the apparent viscosity, shear rate, and shear stress of WPI dispersions. Both the consistency index (k) and the flow behavior index (n) were sensitive to changes in pH and protein concentration. Mathematical relations obtained from experimental values of k and n allowed the determination of a model for apparent viscosity (eta) of WPI dispersions as a function of pH and protein concentration. At 5 and 10% BiPRO, whatever the pH, the rheological behavior appeared to be a newtonian fluid, while at 20% BiPRO, the rheological behavior appeared to be a nonnewtonian pseudoplastic fluid. Furthermore, at 20% Bipro, the apparent viscosity presented an increase in viscosity from 5.6 to 5.4, followed by a decrease from pH 5.4 to 5.0 at all shear rates. The highest viscosity was obtained at 20% pH 5.4, with an approximate value of 0.25 Pa.s, 10 times higher than the one obtained at 5 and 10% BiPRO. 相似文献
Four bulking agents, pine shavings, mixed (long and chopped) grass hay, chopped grass hay and long (whole) wheat straw, were each mixed with pig slurry and tap water to obtain three moisture contents (MC) of 60, 65 and 70%. Quadruplets of each treatment were placed in laboratory composting vessels with a capacity of 105 l and a composting depth of 0·95 m. Using the air plenum at the bottom of each vessel, air was forced at apparent velocities of 0–0·002 m s−1 through each compost mass to measure the air static pressure drop across the compost mass as a function of apparent air velocity. Airflow resistance values were measured for compost depths ranging from 0·55 to 0·85 m. Following this test, all mixtures were aerated for 21 days of composting without overturning. The static pressure measurement procedure was then repeated on all quadruplet mixtures.The air static pressure drop was found with respect to a packed bed under laminar flow, defined using the particle size distribution, porosity, depth and airflow channel characteristics of the compost material. Although MC affected the value of the airflow channel characteristics of the compost material, both the hay and straw demonstrated similar values, while shavings demonstrated values more variable and wider values for MC between 60 and 70%.There was a significant increase in airflow resistance after 21 days of composting, which supports the need for compost overturning to reestablish the material's structure and to restore the airflow channels or pores. 相似文献