Measurements of Vapor Pressures of Aqueous Amino Acid Solutions and Determination of Activity Coefficients of Amino Acids

1997 ◽  
Vol 42 (3) ◽  
pp. 470-474 ◽  
Author(s):  
Hidetoshi Kuramochi ◽  
Hidetaka Noritomi ◽  
Daisuke Hoshino ◽  
Kunio Nagahama
2016 ◽  
Vol 283 (1839) ◽  
pp. 20160996 ◽  
Author(s):  
Noboru Katayama ◽  
Kobayashi Makoto ◽  
Osamu Kishida

Conventional food-web theory assumes that nutrients from dissolved organic matter are transferred to aquatic vertebrates via long nutrient pathways involving multiple eukaryotic species as intermediary nutrient transporters. Here, using larvae of the salamander Hynobius retardatus as a model system, we provide experimental evidence of a shortcut nutrient pathway by showing that H. retardatus larvae can use dissolved amino acids for their growth without eukaryotic mediation. First, to explore which amino acids can promote larval growth, we kept individual salamander larvae in one of eight different high-concentration amino acid solutions, or in control water from which all other eukaryotic organisms had been removed. We thus identified five amino acids (lysine, threonine, serine, phenylalanine, and tyrosine) as having the potential to promote larval growth. Next, using 15 N-labelled amino acid solutions, we demonstrated that nitrogen from dissolved amino acids was found in larval tissues. These results suggest that salamander larvae can take up dissolved amino acids from environmental water to use as an energy source or a growth-promoting factor. Thus, aquatic vertebrates as well as aquatic invertebrates may be able to use dissolved organic matter as a nutrient source.


1985 ◽  
Vol 248 (3) ◽  
pp. G307-G312 ◽  
Author(s):  
J. C. Reynolds ◽  
A. Ouyang ◽  
S. Cohen

Intraluminal pressures and myoelectric activity were recorded from the feline antrum, pylorus, and duodenum in response to intraduodenal amino acid solutions. Mixed amino acids (0.02 mg/ml, 3.0 ml) increased the amplitude of pyloric contractions (59.7 +/- 7.9 mmHg) and pyloric spike activity (73.7 +/- 6.8% of slow waves with spike activity) compared with a saline control (P less than 0.001). The selectivity of these responses was determined with specific amino acids. L-Tryptophan (10 or 40 mM) produced a response similar to the mixed amino acid response, while L-phenylalanine or L-glycine (10 or 40 mM) had no effect. Intra-arterial tetrodotoxin, intraluminal ethyl aminobenzoate, or intravenous naloxone (1.0 mg/kg) abolished the pyloric responses to amino acids (P less than 0.02). Bilateral cervical vagotomy had no effect. Cholecystokinin octapeptide (CCK-OP) produced dose-dependent increases in the amplitude of pyloric contractions and in pyloric spike activity. The ED50 dose of CCK-OP (1.0 microgram/kg iv) gave an increase in pyloric pressure of 155.6 +/- 49.9 mmHg and in spike activity of 77.7 +/- 9.4%, similar to mixed amino acids or tryptophan. These effects of CCK-OP were not antagonized, however, by a dose of naloxone (1.0 mg/kg) that blocked the maximal pyloric response to leucine-enkephalin. We concluded intraduodenal mixed amino acids or tryptophan increase phasic, spike-dependent pyloric contractions in the cat via nonvagal, naloxone-sensitive neural pathways, phenylalanine, a structurally similar essential amino acid, had no effect on the feline gastroduodenal junction, and the pyloric responses to exogenous CCK-OP are mediated by pathways distinct from the responses to tryptophan or mixed amino acids.


2007 ◽  
Vol 42 (3) ◽  
pp. 368-374
Author(s):  
Herbert N. Nigg ◽  
Rhonda A. Schumann ◽  
Jing J. Yang ◽  
Suzanne Fraser

The consumption of amino acids by Anastrepha suspensa Loew (Caribbean fruit fly) was quantified by measuring individual fly consumption. For no-choice tests, there were no differences in consumption between 0.2 M sucrose and 0.2 M sucrose plus L-alanine, L-glycine, L-histidine, L-phenylalanine, or L-serine solutions. There was increased consumption of 0.05 M L-lysine by 6-d males and of 0.03 M L-valine solutions by 6-d females compared to sucrose alone. Choice tests showed higher consumption of 0.2 M sucrose plus L-lysine, L-valine, and L-glycine, particularly by 6-d-old flies. There was a 3–8X increase in consumption of 0.05 M L-valine in 0.2 M sucrose for 6-d males and females. Commercial L-lysine, L-methionine, and L-taurine were not different from controls in no-choice tests; L-cysteine was about 95% inhibitory for consumption. Based on these data, better consumed A. suspensa baits might be formulated by eliminating L-cysteine and including 0.05 M L-valine.


1988 ◽  
Vol 88 (10) ◽  
pp. 6529-6533 ◽  
Author(s):  
Richard P. Kennan ◽  
Jeffrey F. Himm ◽  
Gerald L. Pollack

DICP ◽  
1989 ◽  
Vol 23 (10_suppl) ◽  
pp. S44-S46
Author(s):  
Linda S. Bullock

The use of histamine2-receptor antagonists could be beneficial in critically ill patients for protection against stress-induced gastrointestinal bleeding. Famotidine, similar to cimetidine and ranitidine, is stable when mixed in dextrose 5% injection and NaCl 0.9% injection at a concentration of 200 μg/mL and stored in polyvinyl chloride bags at 4 °C for 14 days or when frozen for 28 days and subsequently refrigerated for 14 days. Furthermore, famotidine, also like cimetidine and ranitidine, is stable when added to most common total parenteral nutrition (TPN) solutions. Famotidine in concentrations of 20 mg/L and 40 mg/L is stable in crystalline amino acid solutions (20 g/L and 42.5 g/L) when refrigerated for 24 hours, then held at room temperature for 24 hours, at room temperature for 48 hours, or refrigerated for seven days. The concentration of amino acids in the TPN solutions containing 42.5 g/L also is not affected by the addition of famotidine 40 mg/L when stored under conditions similar to those stated above for 48 hours. TPN solutions remain clear and free of turbidity.


1993 ◽  
Vol 27 (2) ◽  
pp. 146-150
Author(s):  
Michael L. Christensen ◽  
Julienne Burgess ◽  
Richard A. Helms ◽  
Joseph Mirro ◽  
David K. Kalwinsky ◽  
...  

Objective To assess the effect of parenteral amino acid solutions on plasma amino acid concentrations in patients with acute nonlymphocytic leukemia (ANLL) receiving parenteral nutrition (PN). Design Ten patients were studied at diagnosis, on the morning PN was started, and three times during PN therapy coinciding with the sequential administration of three different amino acid solutions (Aminosyn, FreAmine HBC, and TrophAmine). The order of amino acid solution administration in each patient was by a randomized, block design. Results The patients were undergoing identical intensive induction therapy. There was no significant difference in the number of days they received PN or the amount of protein or calories received during the three PN study periods. At diagnosis, phenylalanine and glutamic acid concentrations were elevated compared with previously published normal values and remained elevated at all observation times. During PN, asparagine, aspartic acid, and tyrosine concentrations were significantly lower with all three amino acid solutions compared with their concentrations at diagnosis. Glycine and threonine concentrations were also significantly lower with FreAmine HBC and TrophAmine administration and cysteine concentrations were significantly lower with FreAmine HBC administration than at the time of diagnosis. Aminosyn was associated with plasma amino acid concentrations most similar to those measured at diagnosis. Conclusions These results indicate that most amino acid concentrations fall within the normal range at diagnosis in the ANLL patients studied. Plasma concentrations for certain amino acids can be influenced by the amino acid solution used in PN. Further understanding of the derangements in amino acid metabolism and the influence of parenterally administered amino acid solutions on plasma amino acid concentrations may lead to improvements in the nutritional support of cancer patients.


1993 ◽  
Vol 13 (4) ◽  
pp. 280-288 ◽  
Author(s):  
Min Sun Park ◽  
Olof Heimbürger ◽  
Jonas Bergström ◽  
Jacek Waniewski ◽  
Andrzej Werynski ◽  
...  

Objective To evaluate the potential clinical role of amino acids as an osmotic agent. Design The peritoneal transport of fluid, amino acids, and other solutes was investigated during a 6–hour single-cycle peritoneal dialysis with PDA 1% versus 1.36% glucose (n=6) or PDA 2.7% versus 3.86% glucose solution (n=9). Patients Fifteen stable nondiabetic continuous ambulatory peritoneal dialysis (CAPD) patients. Results The fractional absorption of the osmotic agents at 6 hours was higher with PDA 2.7% versus glucose 3.86% (p<0.005). The diffusive mass transport coefficient, KeD’ calculated for a period of dialysate isovolemia was higher with PDA 2.7% versus PDA 1% for essential, nonessential (p<0.005), and total (p<0.05) amino acids. The intraperitoneal volume-over-time curves and KqD values for urea, creatinine, glucose, albumin, β2microglobulin, and total protein did not differ between the amino acid solutions and the corresponding glucose solutions. KeD for urea was significantly higher during the dwell with PDA 2.7% versus PDA 1% (p<0.05). Plasma amino acid concentrations increased substantially during the first 1– 2 hours and then decreased gradually. Valine and methionine rose to 792% and 1119% of baseline values, respectively. Conclusions We conclude that the peritoneal transport of fluid and investigated solutes, except amino acids, was not different with the amino acid solutions compared with the corresponding equimolar glucose solutions. However, ultrafiltration tended to be lower with amino acid solutions. Furthermore, the fractional absorption of amino acids and KeD values for amino acids was higher with PDA 2.7% versus PDA 1 %, suggesting an effect of the hypertonic amino acid solution on the peritoneal membrane transport properties. Also, the hypertonic PDA2.7% solution yielded nonphysiologically high plasma levels of several amino acids. We therefore consider this solution not to be safe enough for long term clinical use.”


2019 ◽  
Vol 57 (1) ◽  
pp. 91-94
Author(s):  
Vera A. Petrukhina ◽  
◽  
Pavel I. Fedorov ◽  
Tatiana A. Kirillova ◽  
Ludmila Yu. Tcareva ◽  
...  

It is well-known fact that water is a universal solvent due to its physicochemical properties and dielectric constant. Therefore, the majority of substances with a crystalline structure and the structure close to it are well soluble in water due to the dissociation of molecules into ions. Amino acids are organic ampholytes – substances capable of being in ionic forms in water. The quantitative and qualitative composition of ampholytes depends on the structure and composition of amino acids and pH of solution. The interaction of amino acid ions in solution with hydrogen ions and hydroxyl leads to the formation of complex cations and anions. The presence of amino and carboxyl groups in amino acid molecules contributes to the formation of inter-ion positively and negatively charged complexes which leads to the decrease in their mobility and electrical conductivity of solutions. It is observed with increasing concentration of amino acid solutions. The conductivity of amino acid solutions is also influenced by temperature which has a non-linear relationship. We have proposed the approach based on studying the effect of temperature on the equivalent electrical conductivity at infinite dilution λ∞ and describing the experimental data λ∞(Т) by the exponential Arrhenius equation. This article studies the possibility of describing the experimental data λ∞(Т) for aqueous solutions of a number of amino acids by this equation. It is shown that the Arrhenius equation with the found activation energy values adequately describes the dependences of limiting equivalent conductivity on temperature for aqueous solutions of valine, leucine, isoleucine, threonine, lysine, methionine, phenylalanine, L-aspartic and D-aspartic acids, histidine, arginine.


Sign in / Sign up

Export Citation Format

Share Document