Asp Concentration Research Articles

Effects of exercise and dietary interventions on asprosin, leptin, and lipid metabolism in males with abdominal obesity, a randomized controlled trial

Addressing abdominal obesity requires multifaceted strategies, with physical activity and diet playing a pivotal role. The objective of this study was to assess alterations in body composition, adipokine concentrations, insulin resistance parameters, and lipid metabolism in males with abdominal obesity following two distinct interventions: exercise alone and exercise combined with a specific diet. The study involved 44 males with abdominal obesity (average age 34.7 ± 5.5 years, waist circumference [WC] 110.3 ± 8.5), randomly assigned to three groups: an experimental group with aerobic-resistance exercise (EG, n = 16), an experimental group with aerobic-resistance exercise combined with a high-protein, low-glycemic index carbohydrate diet (EDG, n = 16), both interventions lasting 6 weeks, and a control group without interventions (CG, n = 12). Body composition (body mass [BM], body fat percentage [BF%], fat-free mass [FFM], android body fat percentage [ANDR]), as well as biochemical blood analyses (asprosin [ASP], leptin [LEP], quantitative insulin sensitivity check index [QUICKI], and total cholesterol [TC]), were conducted at baseline and after 6 weeks of intervention. The impact of interventions on the analyzed variables among groups was assessed using mixed ANOVA tests with post-hoc comparisons. Effect size (ES) was also evaluated using \U0001d702p2. Significant reductions in ASP concentration after intervention were observed in both EG (p = 0.04) and EDG (p = 0.01). However, post-hoc tests revealed a decrease in LEP only in the EDG group (p < 0.01). In EDG substantial decreases after 6 weeks of intervention were noted in BM (p < 0.01), BF% (p < 0.01), ANDR (p < 0.01) and TC (p < 0.01). The most notable increase in FFM was observed in the EDG group (p < 0.01). More favourable metabolic outcomes were confirmed in the group combining diet with exercise, where there was a notable reduction in ASP levels by 16% and LEP by 48% after 6 weeks of intervention, compared to the group undergoing exercise alone.

Exploring the role of aspartic acid in modulating micellization behavior of cationic cetyltrimethylammonium bromide

The study of the interaction between aspartic acid (Asp) and cetyltrimethylammonium bromide (CTAB) reveals important information about surfactant organization, surface tension, critical micelle concentration (CMC), and surface pressure. Because of enhanced surfactant solubility brought about by electrostatic interactions, Asp’s ionization lowers CTAB’s CMC. The maximal surface excess concentration falls with increasing Asp concentration, suggesting competition for surface adsorption. The minimum occupied area per surfactant molecule increases at the same time, indicating changed surfactant activity at the interface between air and water. Higher CTAB concentrations are associated with a decrease in surface tension, which suggests that when Asp concentration rises, micelle formation would be promoted. Saturation effects, on the other hand, happen at high Asp concentrations and interfere with micelle formation. These tendencies are supported by surface pressure measurements, highlighting the significance of ionic interactions in micelle behavior.Moreover, surfactant structuring is impacted by the packing parameter decreasing as Asp concentration increases. The changing balance between hydrophilic and hydrophobic interactions within the CTAB/Asp micellar complexes is further explained by variations in degree of counterion dissociation of micelles (α) values. The complex dynamics of ionic interactions and their impact on surfactant behavior in CTAB/Asp systems are highlighted by these studies.

DESKRIPTIF KUALITATIF ALASAN MAHASISWA AKUNTANSI FAKULTAS EKONOMI UNPATTI MEMILIH KONSENTRASI AKUNTANSI SEKTOR PUBLIK

&lt;p align="justify"&gt;This study aims to find out the reasons students majoring in accounting at the Faculty of Economics, Pattimura University decided to choose a concentration in public sector accounting, to be precise, students in their sixth semester of the 2022/2023 academic year. This research is a type of qualitative research using an interpretive paradigm. Retrieval of data using interviews packaged in the form of Fucus Group Discussion. The results showed that the reasons for students choosing the ASP (Public Sector Accounting) concentration were due to the preparation of their final project, preferred career goals, factors of interest in Public Sector Accounting, perceptions of wider availability of employment opportunities, perceptions of ASP courses tend to be easier, as well as factors teaching lecturer. Another finding is that almost all respondents are interested in a career as a government employee, although not all stated that the reason for choosing the ASP concentration was because of this.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Keywords&lt;/strong&gt;: Concentration, Accounting, Public, Qualitative, Interpretive&lt;/p&gt;

Impact of Molecular Surface Diffusion on the Physical Stability of Co-Amorphous Systems.

In this study, surface diffusion of l-aspartic acid-carvedilol (ASP-CAR) co-amorphous systems at different ASP concentrations is measured and correlated with their physical stability. ASP-CAR films at ASP concentrations of 1-5% (w/w) were prepared by a newly developed method based on a vacuum compression molding process. Surface diffusion measurements were conducted on these systems based on the surface grating decay method using atomic force microscopy (AFM). The results demonstrate that a small amount of ASP (i.e., ≤ 5% w/w) in the co-amorphous systems could significantly slow down the grating decay process compared with that of pure amorphous CAR, indicating a reduced surface diffusion of CAR molecules. The decay time gradually increased in co-amorphous systems with increasing ASP concentration from 1 to 5% (w/w), with the longest observed decay time of around 800 h for the 5%ASP-CAR system, which was more than 200 times longer compared to the decay time of pure amorphous CAR (approximately 3 h). A good correlation between the decay constants of the pure amorphous CAR and co-amorphous films at ASP concentrations of 1-5% (w/w) and the physical stability of corresponding amorphous powder samples was found. Overall, this study provides a new method to prepare co-amorphous films for surface property measurements and reveals the impact of surface diffusion on the physical stability of co-amorphous systems.

Thermodynamic Impact of Mineral Surfaces on Amino Acid Polymerization: Aspartate Dimerization on Two-Line Ferrihydrite, Anatase, and γ-Alumina

The presence of amino acids in diverse extraterrestrial materials has suggested that amino acids are widespread in our solar system, serving as a common class of components for the chemical evolution of life. However, there are a limited number of parameters available for modeling amino acid polymerization at mineral–water interfaces, although the interfacial conditions inevitably exist on astronomical bodies with surface liquid water. Here, we present a set of extended triple-layer model parameters for aspartate (Asp) and aspartyl-aspartate (AspAsp) adsorptions on two-line ferrihydrite, anatase, and γ-alumina determined based on the experimental adsorption data. By combining the parameters with the reported thermodynamic constants for amino acid polymerization in water, we computationally demonstrate how these minerals impact the AspAsp/Asp equilibrium over a wide range of environmental conditions. It was predicted, for example, that two-line ferrihydrite strongly promotes Asp dimerization, leading to the AspAsp/Asp ratio in the adsorbed state up to 41% even from a low Asp concentration (0.1 mM) at pH 4, which is approximately 5 × 107 times higher than that attainable without mineral (8.5 × 10−6%). Our exemplified approach enables us to screen wide environmental settings for abiotic peptide synthesis from a thermodynamic perspective, thereby narrowing down the geochemical situations to be explored for life’s origin on Earth and Earth-like habitable bodies.

Salicylic acid regulates adventitious root formation via competitive inhibition of the auxin conjugation enzyme CsGH3.5 in cucumber hypocotyls.

Exogenous SA treatment at appropriate concentrations promotes adventitious root formation in cucumber hypocotyls, via competitive inhibiting the IAA-Asp synthetase activity of CsGH3.5, and increasing the local free IAA level. Adventitious root formation is critical for the cutting propagation of horticultural plants. Indole-3-acetic acid (IAA) has been shown to play a central role in regulating this process, while for salicylic acid (SA), its exact effects and regulatory mechanism have not been elucidated. In this study, we showed that exogenous SA treatment at the concentrations of both 50 and 100µM promoted adventitious root formation at the base of the hypocotyl of cucumber seedlings. At these concentrations, SA could induce the expression of CYCLIN and Cyclin-dependent Kinase (CDK) genes during adventitious rooting. IAA was shown to be involved in SA-induced adventitious root formation in cucumber hypocotyls. Exposure to exogenous SA led to a slight increase in the free IAA content, and pre-treatment with the auxin transport inhibitor 1-naphthylphthalamic acid (NPA) almost completely abolished the inducible effects of SA on adventitious root number. SA-induced IAA accumulation was also associated with the enhanced expression of Gretchen Hagen3.5 (CsGH3.5). The in vitro enzymatic assay indicated that CsGH3.5 has both IAA- and SA-amido synthetase activity and prefers aspartate (Asp) as the amino acid conjugate. The Asp concentration dictated the functional activity of CsGH3.5 on IAA. Both affinity and catalytic efficiency (Kcat/Km) increased when the Asp concentration increased from 0.3 to 1mM. In contrast, CsGH3.5 showed equal catalytic efficiency for SA at low and high Asp concentrations. Furthermore, SA functioned as a competitive inhibitor of the IAA-Asp synthetase activity of CsGH3.5. During adventitious formation, SA application indeed repressed the IAA-Asp levels in the rooting zone. These data show that SA plays an inducible role in adventitious root formation in cucumber through competitive inhibition of the auxin conjugation enzyme CsGH3.5. SA reduces the IAA conjugate levels, thereby increasing the local free IAA level and ultimately enhancing adventitious root formation.

Resilient Intracrystalline Occlusions: A Solid-State NMR View of Local Structure as It Tunes Bulk Lattice Properties.

In many marine organisms, biomineralization—the crystallization of calcium-based ionic lattices—demonstrates how regulated processes optimize for diverse functions, often via incorporation of agents from the precipitation medium. We study a model system consisting of l-aspartic acid (Asp) which when added to the precipitation solution of calcium carbonate crystallizes the thermodynamically disfavored polymorph vaterite. Though vaterite is at best only kinetically stable, that stability is tunable, as vaterite grown with Asp at high concentration is both thermally and temporally stable, while vaterite grown at 10-fold lower Asp concentration, yet 2-fold less in the crystal, spontaneously transforms to calcite. Solid-state NMR shows that Asp is sparsely occluded within vaterite and calcite. CP-REDOR NMR reveals that each Asp is embedded in a perturbed occlusion shell of ∼8 disordered carbonates which bridge to the bulk. In both the as-deposited vaterites and the evolved calcite, the perturbed shell contains two sets of carbonate species distinguished by their proximity to the amine and identifiable based on 13C chemical shifts. The embedding shell and the occluded Asp act as an integral until which minimally rearranges even as the bulk undergoes extensive reorganization. The resilience of these occlusion units suggests that large Asp-free domains drive the vaterite to calcite transformation—which are retarded by the occlusion units, resulting in concentration-dependent lattice stability. Understanding the structure and properties of the occlusion unit, uniquely amenable to ssNMR, thus appears to be a key to explaining other macroscopic properties, such as hardness.

Maternal nutrition and stage of early pregnancy in beef heifers: impacts on hexose and AA concentrations in maternal and fetal fluids1.

We examined the hypothesis that maternal nutrition and day of gestation would affect the concentrations of AAs and hexoses in bovine utero-placental fluids and maternal serum from days 16 to 50 of gestation. Forty-nine cross-bred Angus heifers were bred via artificial insemination and fed a control diet (CON = 100% of requirements for growth) or a restricted diet (RES = 60% of CON) and ovariohysterectomized on days 16, 34, or 50 of gestation; nonpregnant controls were not bred and ovariohysterectomized on day 16 of the synchronized estrous cycle. The resulting design was a completely randomized design with a 2 × 3 factorial + 1 arrangement of treatments. Maternal serum, histotroph, allantoic fluid, and amniotic fluid were collected at time of ovariohysterectomy. Samples were then analyzed for concentrations of AAs and intermediary metabolites: alanine (Ala), arginine, asparagine (Asn), aspartate (Asp), citrulline, cysteine, glutamine, glutamate (Glu), glycine (Gly), histidine, isoleucine, leucine (Leu), lysine, methionine (Met), ornithine, phenylalanine (Phe), proline (Pro), serine (Ser), threonine (Thr), tryptophan, tyrosine (Tyr), and valine (Val). The concentrations of Gly, Ser, and Thr in maternal serum were greater (P ≤ 0.05) in CON compared with RES. Furthermore, day of gestation affected (P ≤ 0.05) concentrations of Asn, Glu, Phe, Thr, and Tyr in maternal serum. Status of maternal nutrition affected the Asp concentration of histotroph where RES was greater (P = 0.02) than CON. In histotroph, Ala, Leu, Met, and Val concentrations were greater (P ≤ 0.05) on day 50 compared with day 16. Additionally, Glu and Pro concentrations in histotroph were greater (P < 0.01) on days 34 and 50 compared with day 16. A day × treatment interaction was observed for the concentration of Val in allantoic fluid where day 34 CON was greater (P = 0.05) than all other days and nutritional treatments. In addition, the concentration of Gln in amniotic fluid experienced a day × treatment interaction where day 34 RES was greater (P ≤ 0.05) than day 34 CON, which was greater (P ≤ 0.05) than day 50 CON and RES. These data support our hypothesis that day of gestation and maternal nutrition affect the concentrations of various neutral and acidic AA in beef heifer utero-placental fluids and maternal serum from days 16 to 50 of gestation.

Inhibition of Naphthenates Emulsion Soaps Chemical EOR using Synthesis Compound Derived from Fatty Hydrazide.

Naphthenates soaps emulsion generated from alkaline (A), surfactant (S) and polymer (P) flooding were studied with crude oil contained amphiphilic carboxylic acids, RCOOH from Malaysian oilfield. These naphthenic acids were characterised using high-resolution fourier transform ion-cyclotron resonance mass spectroscopy (FTCIR-MS). Alkaline Na2CO3 resulted in increase in pH of produced water to between pH 9 to 11 and generates in-situ oil-rich colloidal dispersion ultralow interfacial tension (IFT) character of sodium carboxylate soaps emulsion. Predictive measurement and inhibition were evaluated using new naphthenate inhibitor (NI)- demulsifier synthesized from fatty hydrazide. The structures of the synthesized compounds have been established by FTIR, 1H NMR, 13C NMR, and mass spectrometry (LCMS/MS). Inhibition and demulsification properties have been evaluated at operating parameters such as produce water cut level, ASP concentration and temperatures under dynamic testing condition using Multifunctional Mini Flow Loop (MMFLTM).

Effect of protein or energy restriction during late gestation on hormonal and metabolic status in pregnant goats and postnatal male offspring

The objective of this study was to investigate the effects of maternal protein or energy restriction on hormonal and metabolic status of pregnant goats during late gestation and their postnatal male kids. Forty-five pregnant goats were fed a control (CON), 40% protein-restricted (PR) or 40% energy-restricted (ER) diet from 90 days of gestation until parturition. Plasma of mothers (90, 125 and 145 days of gestation) and kids (6 weeks of age) were sampled to determine metabolites and hormones. Glucose concentration for pregnant goats subjected to PR or ER was less (P<0.001) than that of CON goats at 125 and 145 days of gestation. However, plasma nonesterified fatty acids concentration was greater (P<0.01) at 125 and 145 days for PR and ER than CON. Protein restriction increased (P<0.01) maternal cortisol concentration by 145 days of gestation, and ER decreased (P<0.01) maternal insulin concentration at 125 days of gestation. Moreover, maternal amino acid (AA) concentrations were affected by nutritional restriction, with greater (P<0.05) total AA (TAA) and nonessential AA (NEAA) for PR goats but less (P<0.05) TAA and NEAA for ER goats at 125 days of gestation. After 6 weeks of nutritional recovery, plasma concentrations of most metabolic and hormonal parameters in restricted kids were similar to CON kids, except for reduced (P<0.05) insulin concentration in ER, and reduced (P<0.05) Asp concentration in PR and ER kids. These results provide information on potential metabolic mechanisms responsible for fetal programming.

The Effect of Aspartic Acid and Glycine on Amorphous Calcium Carbonate (ACC) Structure, Stability and Crystallization

The effect of organic molecules on CaCO3 crystallization, in particular on the formation of the initial amorphous calcium carbonate (ACC) phase, is poorly understood despite this knowledge being crucial for designing biomimetic compounds with specific function, strength and stability. We monitored ACC crystallization in the presence of varying concentrations of aspartic acid (ASP) and glycine (GLY). We observed an increase in ACC lifetime with increasing amino acid concentrations and showed that the amino acid molecules sorbed onto the ACC particles. However, little if any difference in composition and atomic structure or the so formed ACC was observed. Similarly, the crystallization pathway of ACC via vaterite and calcite although delayed, was only slightly affected by the added amino acids. The only exemption was at the highest tested ASP concentration where ACC formation was inhibited, The calcite crystals that formed in the presence of ASP had rounded edges and rough surfaces, features that are not observed for the pure, inorganic calcite or calcite formed in the presence of GLY. Overall, the results suggest that the amino acids affected ACC lifetime through the inhibition of crystal nucleation and growth, more so in the presence of ASP than GLY.

Asparagine quantification in cellular culture media using copper modified carbon nanotubes composite electrodes

Direct quantification of Asparagine (Asp) in a Streptomyces sp. M7 ( SM7) culture medium was performed using multi-wall carbon nanotubes composite electrodes modified with copper microparticles (CNTPE-Cu). A sensitive and fast response is achieved at CNTPE-Cu after additions of SM7 cultures supernatant, without interference of the culture medium components. This response allows determining the Asp concentration as a function of the bacteria growth. The results reveal that the SM7 bacteria consume Asp as a carbon and nitrogen sources in the absence of another carbon source such as glucose.

Influence of the magnesium aspartate hydrochloride administration to the maternal circuit on the aspartate concentration of the fetal circuit under in vitro perfusion of human placenta

Objectives Magnesium aspartate hydrochloride (Magnesiocard ®, Mg–Asp–HCl) is proposed as a substitute of magnesium sulfate for the treatment of preeclampsia and premature labor. After an i.v. administration of a dose equivalent to that used in the treatment of preeclampsia to nonpregnant volunteers, a 10-fold increase of aspartic acid (Asp) over the physiological level was observed. Animal experiments have demonstrated that highly increased fetal levels of acidic amino acids such as Asp could be associated with neurotoxic damage in the fetal brain. The influence of such an elevation of Asp concentration in the maternal circuit on the fetal level, using the in vitro perfusion model of human placenta, was investigated. Study design After a control phase (2 h), a therapeutic dose of Mg combined with Asp (Magnesiocard ®, Mg–Asp–HCl) was applied to the maternal circuit approaching 10 times the physiological level of Asp. The administration was performed in two different phases simulating either a peak of maximum concentration (bolus application, 2 h) or a steady state level (initially added, 4 h). Results In four experiments, during experimental phases (6 h) a slow increase in concentration in the fetal circuit was seen for Mg, AIB (alpha-aminoisobutyric acid, artificial amino acid) and creatinine confirming previous observations. In contrast, no net transfer of Asp across the placenta was seen. A continuous decrease in the concentration of Asp on both maternal and fetal side suggests active uptake and metabolization by the placenta. Viability control parameters remained stable indicating the absence of an effect on placental metabolism, permeability and morphology. Conclusion Elevation of Asp concentration up to 10 times the physiological level by the administration of Mg–Asp–HCl to the maternal circuit under in vitro perfusion conditions of human placenta has no influence on the fetal level of Asp suggesting no transfer of Asp from the maternal to fetal compartment. Therefore, the administration of Mg–Asp–HCl to preeclamptic patients would be beneficial for the patients without any impact on placental or fetal physiology.

Effects of Aspartic Acid on Calcite Dissolution Rate and Solubility

Abstract The dissolution rate and solubility of calcite, a polymorph of CaCO3, were determined in aspartic acid (Asp) solutions: Asp inhibited the surface reaction of calcite dissolution but accelerated the transport process. The crossover of these contrastive effects caused a local maximum of the dissolution rate constant and the transition of rate-determining processes. The calcite solubility increased with increasing Asp concentration, which may reflect its association with the change of the calcite surface structure derived from the addition of Asp.

Pharmacodynamics and Tolerability of Twice-Weekly Erwinia Asparaginase after E. coli Asparaginase Allergy in Children with ALL.

BACKGROUND: E.coli L-asparaginase (ASP) is an important component of multiagent chemotherapy for childhood ALL; however, allergic symptoms develop in 25–30% of patients (pts). Erwinia ASP is an alternative preparation which has been used after E.coli ASP allergy; however, it has not been previously shown how well E.coli ASP-allergic pts tolerate Erwinia ASP or whether they achieve therapeutic ASP levels.METHODS: On DFCI ALL Consortium Protocol 00–01 (2000–2005), newly diagnosed children with ALL (aged 1–18 years) received 30 weeks (wks) of IM ASP during consolidation beginning 7 weeks after diagnosis. All pts initially received weekly E.coli ASP. Nadir serum ASP concentrations were measured every 3 wks by a validated biochemical assay and antibodies to E.coli and Erwinia ASP were measured by ELISA every 6 wks. If E.coli ASP allergy developed, children received Erwinia ASP (25000 IU/m2/dose twice weekly) until 2003, when Erwinia ASP became unavailable.RESULTS: We analyzed the data of all 44 patients treated between 2000–2002 who received Erwinia ASP after E.coli ASP-allergy. Median age at diagnosis was 5.5 years. Median duration of E.coli ASP prior to development of allergy was 5 wks (range 1–23). 26 (59%) pts were positive for E.coli ASP antibodies. Erwinia ASP toxicities included: allergy in 15 (34%) pts (which occurred a median 8 wks after starting Erwinia, range 2–15.5), pancreatitis in 1 (2%) and insulin-requiring hyperglycemia in 1 (2%) pt. 18 (41%) pts became positive for Erwinia ASP antibodies, 4 of whom developed Erwinia ASP allergy. Highest nadir ASP concentrations observed after Erwinia ASP in the 44 E.coli-allergic pts are displayed in the Table (below). Prior data has suggested that a nadir serum ASP level of >=0.1 IU/mL is associated with asparagine depletion (therapeutic level).Nadir Serum ASP Levels after Erwinia ASP in E.coli ASP-allergic ptsNMedian (range) ASP Level (IU/mL)% with ASP Level >= 0.1 IU/mLAll E.coli ASP allergic pts440.231(0.00–3.33)84%Subsequent allergy to ErwiniaYes150.418 (0.00–3.33)80%No290.215 (0.00–0.93)86%E.coli ASP antibodypositive260.171 (0.00–3.33)73%negative180.318 (0.10–0.93)100%Erwinia ASP antibodyPositive180.171 (0.00–3.33)72%negative260.322 (0.00–0.93)92%Highest ASP concentration with E.coli ASP prior to allergySubtherapeutic(<0.1 IU/mL)200.221 (0.00–1.04)85%Therapeutic(>=0.1 IU/mL)240.323 (0.00–3.33)83%Excluding pts who switched to PEG when Erwinia became unavailable in 2003 (N=11), pts remained on Erwinia ASP for a median of 16 wks (range 2–28). 31 pts (70%) ultimately completed all planned 30 wks of ASP consolidation.CONCLUSIONS: We conclude that twice-weekly Erwinia ASP is well-tolerated and achieves detectable and potentially therapeutic serum ASP levels in the majority of E.coli ASP-allergic pts, including those with ASP antibodies (E.coli and/or Erwinia), pts who developed subsequent allergy to Erwinia ASP and pts who never achieved therapeutic nadir levels with prior E.coli ASP. Erwinia ASP should be considered as alternative therapy for pts with ALL who develop E.coli ASP allergy.

Effects of aspartic acid and potassium chloride on arginine kinase from shrimp

The aspartic acid (Asp)-induced unfolding and the salt-induced folding of arginine kinase (AK) were studied in terms of enzyme activity, intrinsic fluorescence emission spectra, 1-anilino-8-naphthalenesulfonate (ANS) fluorescence spectra and far-UV circular dichroism (CD) spectra. The results showed that Asp caused inactivation and unfolding of AK with no aggregation during AK denaturation. The unfolding of the whole molecule and the inactivation of AK in different Asp concentrations were compared. Much lower Asp concentration was required to induce inactivation than to produce significant conformational changes of the enzyme molecule. However, with further addition of Asp, the molar ellipticity at 222 and 208 nm, the wavelength shift and the emission intensity of ANS hardly changed. Asp denatured AK was reactivated by dilution. In addition, potassium chloride (KCl) induced the molten globule state with a compact structure after AK was denatured with 7.5 mM Asp. These results collectively elucidate the osmotic effect of Asp anions for the molten globule formed during unfolding process. They also suggest that the effect of Asp differed from that of other denaturants such as guanidine hydrochloride or urea during AK folding. The molten globule state indicates that intermediates exist during AK folding.

Weighting and improvement of silk properties

AbstractSilk was modified with the aim to increase the weight and improve the physical properties. A grafting chemical redox technique was adopted in this investigation by using ammonium persulfate (APS), copper sulfate as initiator and accelelerator for the reaction, glycidyl methacrylate (GM), and acrylamide (AM), or their mixture. The optimum ASP and copper sulfate concentration needed to decrease the homopolymerization reaction was noted in the case of GM and AM. The percentage graft yield was found to be highly affected by the various parameters studied, including the initiator, the monomer concentrations, the reaction time, and the temperature. The physical properties of the grafted silk fabric were done including crease recovery angles, abrasion resistance, and moisture regain. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1743–1747, 2004

Effects of Taurine Deficiency and Chronic Methanol Administration on Rat Retina, Optic Nerve and Brain Amino Acids and Monoamines

A chronic methanol (MeOH) intoxication scheme (2 g/kg/day ip for 2 weeks) was carried out in Sprague-Dawley rats, previously depleted of folates with methotrexate (MTX). β-Alanine (β-Ala), 5%, was also administered to some animals in the drinking water. Amino acids were determined in plasma, retina, optic nerve, hippocampus and posterior cortex by HPLC with fluorescence detection and monoamines in retina, hippocampus and posterior cortex by electrochemical detection. β-Ala administration reduced taurine (Tau) levels in plasma, hippocampus and posterior cortex, but not in retina and optic nerve. Aspartate (Asp) concentration in the optic nerve was increased in MTX-MeOH treated animals, and the administration of β-Ala did not modify this elevation. The association of β-Ala with MTX-MeOH produced an increase of threonine, and a decrease of 5-hydroxytryptamine (5-HT) in the retina without modifying 5-hydroxyindoleacetic acid, whereas in the hippocampus an elevation of asparagine was observed. We conclude that, in the retina, β-Ala in combination with MTX-MeOH increased serotonin and decreased dopamine (DA) turnover rate, and resulted in changes in the amino acid balance, that could affect glycinergic activity. On the other hand, in the hippocampus, Asp metabolism could be affected by Tau depletion with β-Ala.

Extracellular concentrations of taurine, glutamate, and aspartate in the cerebral cortex of rats at the asymptomatic stage of thioacetamide-induced hepatic failure: modulation by ketamine anesthesia.

Subclinical hepatic encephalopathy (SHE) was produced in rats by two intraperitoneal injections of TAA at 24 h intervals and the animals were examined 21 days later. Concentrations of the neuroactive amino acids taurine (Tau), glutamate (Glu) and aspartate (Asp), were measured in the cerebral cortical microdialysates of thioacetamide (TAA)-treated and untreated control rats. During microdialysis some animals were awake while others were anesthetized with ketamine plus xylazine. There was no difference in the water content of cerebral cortical slices isolated from control and SHE rats, indicating a recovery from cerebral cortical edema that accompanies the acute, clinical phase of hepatic encephalopathy in this model. When microdialysis was carried out in awake rats, dialysate concentrations of all the three amino acids were 30% to 50% higher in SHE rats than in control rats. Ketamine anesthesia caused a 2.2% increase of water content of cerebral cortical slices and increased Asp, Glu, and Tau concentration in microdialysates of control rats. In SHE rats, ketamine anesthesia produced a similar degree of cerebral edema, however, it did not alter Asp and Glu concentrations in the microdialysates. These data may reflect on one hand a neuropathological process of excitotoxic neuronal damage related to increased Glu and Asp, on the other hand neuroprotection from neuronal swelling indicated by Tau redistribution in the cerebral cortex. The reduction of the effects of SHE on Glu and Asp content in ketamine-anesthesized rats is likely to be due to interference of ketamine with the NMDA receptor-mediated component of the SHE-evoked excitatory neurotransmitter efflux and/or reuptake of the two amino acids. By contrast, the SHE-related increase of Tau content was not affected by ketamine anesthesia, indicating that the mechanism(s) underlying SHE-evoked accumulation of Tau must be different from the mechanism causing release of excitatory amino acids. The results with ketamine advocate caution when using this anesthetic in studies employing the cerebral microdialysis technique for measurement of extracellular amino acids.

High aspartate accumulation and defect of glutamate/aspartate transport in low potassium dog red blood cells

The accumulation of Asp in low potassium (LK) dog red blood cells (RBCs) with defective Na-dependent (ND) glutamate (Glu)/aspartate (Asp) transport was examined. In RBCs with LK and defective ND-Glu/Asp transport (LK/GAT−), the amino acid influx defect appears to be specific to Glu/Asp, since influxes of the neutral amino acids alanine (Ala) and glutamine (Gln) were similar in both LK/GAT− RBCs and LK dog RBCs without the defect (LK/GAT+). Contrary to what might be expected with this transport defect, the Asp concentration in LK/GAT− RBCs was 10-fold higher than that in LK/GAT+ RBCs. Large, light RBCs separated by specific gravity were younger than small, dense RBCs in both LK/GAT− and LK/GAT+ RBCs. The youngest 10% of the cells had a 20% higher Asp concentration than the oldest 10% of the cells in both LK/GAT+ and LK/GAT− RBCs. The Glu and Gln concentrations decreased by 37%–47% as the cells aged, whereas Asp concentration decreased by 18%–19%. Therefore, the change in Asp metabolism during cell ageing might be smaller than the changes in the other amino acids. Thus, the Asp accumulation perhaps occurs at an early stage of cell development in LK/GAT− RBCs. The most likely cause of the Asp accumulation is a defect in Asp extrusion through ND-Glu/Asp transport.