Postcolumn fluorometric detection system for liquid chromatographic analysis of amino and imino acids using o-phthalaldehyde/N-acetyl-L-cysteine reagent

Determination of o-phthalaldehyde for dose verification of the clinical disinfectant by fluorescent sequential injection analysis

A new automated, generic analytical approach for determining the clinical disinfectant o-phthalaldehyde (OPA) is reported in this study. The proposed sequential injection analysis (SIA) is based on the online reaction of the OPA with glycine/N-acetylcysteine (NAC) in a neutral medium (pH = 7.0) to form a highly fluorescent isoindole derivative. All critical flow and reaction variables were investigated, while validation was carried out in the linearity detection range (0.0075-0.02%). As a result, excellent linearity (R2 > 0.99) and precision (1.5-2.4% for repeatability and 0.7-2.2% for reproducibility) were achieved for the reference OPA solutions. Furthermore, reasonable concentration verification of OPA disinfection (0.2-0.6%) in healthcare institutes can be achieved using the developed fluorescent SIA due to its good sensitivity (0.111 V/%) and precision (1.0-2.3% for intermediate precision) around the minimum effective concentration (MEC) of 0.3% for Cidex-OPA disinfectant.

Body weight reduction by exercise increases the urinary 3-methylhistidine excretion level with relatively positive nitrogen, sodium, and potassium balances when compared to dietary restriction

Background

Regarding changes in muscle mass, differences due to types of exercise and/or nutritional interventions, and associations with nutrient balances are still unclear.

Methods

To estimate changes in muscle mass during a body weight loss program using either a diet or exercise regimen, we investigated levels of muscle mass-related indices, and body contents of nitrogen, sodium, and potassium as measured by the balance method. Six healthy young adult male volunteers participated in two 10-day crossover experiments (20 days total). The first 5 days comprised an adjustment period (energy intake, 2656 ± 367 kcal/day (mean ± standard deviation)). During the second 5-day period, the participants either reduced their energy intake to 1770 ± 244 kcal/day (diet regimen) or exercised on a bicycle ergometer to expend 886 ± 122 kcal/day (exercise regimen).

Results

The nitrogen, sodium, and potassium balances were significantly more positive during the exercise regimen than during the diet regimen. The urinary excretion levels of creatinine, 3-methylhistidine (3-MH), aldosterone, and catecholamines, and the 3-MH/creatinine ratio were significantly increased only during the exercise regimen.

Conclusions

The exercise regimen suppresses the decrease in muscle mass-related indices during body weight loss compared to the diet regimen with a relatively positive state of whole-body protein, sodium, and potassium balances, accompanied by an increase in sympathetic/adrenal cortical functions.

Increase in insulin secretion and decrease in muscle degradation by fat-free milk intake are attenuated by physical exercise

BACKGROUND

Protein intake, particularly branched chain amino acids (BCAAs), and exercise have opposing actions on insulin secretion, but the same action on protein anabolism. We examined the effects of BCAA-rich fat-free milk intake and/or exercise on levels of insulin secretion and indices related to muscle protein metabolism in order to assess the potency of dietary and exercise therapies against metabolic and locomotive disorders.

METHODS

Eight adult female volunteers participated in all four 24 h experiments; control diet intake with or without exercise, and fat-free milk-containing diet intake with or without exercise. Fat-free milk was replaced with one-sixth of all foods in the control diet. Exercise was set at an equal-energy level as fat-free milk. Urine and fasting blood samples were collected for each experiment.

RESULTS

Urinary C-peptide immunoreactivity excretion and serum insulin levels were significantly higher, but urinary 3-methyl-histidine excretion levels were significantly lower with low urinary adrenaline and dopamine excretion in the fat-free milk-containing diet than in the control diet. These findings were reduced by exercise with high urinary adrenaline and noradrenaline excretion.

CONCLUSIONS

BCAA-rich fat-free milk intake enhanced insulin secretion and suppressed muscle protein degradation, but these effects are attenuated by exercise accompanied with increase in catecholamine secretion.

Hydrolysis of trichosanthin (TCS) catalyzed by imidazolium-based ionic liquids in heating and microwave-assisted modes

Two modes of TCS hydrolysis based on ILs were compared and a higher degree of hydrolysis can be obtained compared to common catalysts.

Comparison of Neuroprotective and Cognition-Enhancing Properties of Hydrolysates from Soybean, Walnut, and Peanut Protein

Hydrolysates were prepared from soybean, walnut, and peanut protein by papain, respectively. Their amino acid compositions and molecular weight distributions, the effects of various hydrolysates on H2O2-induced injury PC12 cells, and cognition of mice were investigated, respectively. Results showed that the three hydrolysates were dominated by the peptides with 1–3 KDa with large amount of neurotrophic amino acids. All the hydrolysates exhibited much stronger inhibitory activity against H2O2-induced toxicity than cerebrolysin, and soy protein hydrolysate showed the highest activity. Moreover, the hydrolysates also could reduce the rate of nonviable apoptotic cells at the concentration of 2 mg/mL. The test of animal’s cognition indicated that three hydrolysates could present partly better effect of improving recurred memory ability of normal mice and consolidated memory ability of anisodine-treated mice than piracetam. Therefore, soybean, walnut, and peanut protein hydrolysates were recommended as a potential food raw material for prevention or treatment of neurodegenerative disorders.

Mast cells mediate malignant pleural effusion formation

Mast cells (MCs) have been identified in various tumors; however, the role of these cells in tumorigenesis remains controversial. Here, we quantified MCs in human and murine malignant pleural effusions (MPEs) and evaluated the fate and function of these cells in MPE development. Evaluation of murine MPE-competent lung and colon adenocarcinomas revealed that these tumors actively attract and subsequently degranulate MCs in the pleural space by elaborating CCL2 and osteopontin. MCs were required for effusion development, as MPEs did not form in mice lacking MCs, and pleural infusion of MCs with MPE-incompetent cells promoted MPE formation. Once homed to the pleural space, MCs released tryptase AB1 and IL-1β, which in turn induced pleural vasculature leakiness and triggered NF-κB activation in pleural tumor cells, thereby fostering pleural fluid accumulation and tumor growth. Evaluation of human effusions revealed that MCs are elevated in MPEs compared with benign effusions. Moreover, MC abundance correlated with MPE formation in a human cancer cell-induced effusion model. Treatment of mice with the c-KIT inhibitor imatinib mesylate limited effusion precipitation by mouse and human adenocarcinoma cells. Together, the results of this study indicate that MCs are required for MPE formation and suggest that MC-dependent effusion formation is therapeutically addressable.

A murine model of airway fibrosis induced by repeated naphthalene exposure

The airway epithelium serves as a biological barrier essential for host defense against inhaled pollutants. While chronic epithelial injury, commonly associated with chronic obstructive pulmonary disease and bronchiolitis obliterans syndrome, often results in airway fibrosis, limited animal models of airway fibrosis have been established. Club cells (Clara cells) in the small airways represent an important population of epithelial progenitor cells and also the principal site of localization of the cytochrome P-450 monooxygenase system, which metabolically activates xenobiotic chemicals such as naphthalene by converting them to toxic epoxide intermediates. We hypothesized that repeated exposure to naphthalene may cause prolonged loss of club cells, triggering aberrant local epithelial repair mechanisms that lead to peribronchial fibrosis. We administered intraperitoneal injections of naphthalene to C57/BL6J mice once a week for 14 consecutive weeks. Repeated club cell injury caused by naphthalene triggered regional hyperproliferation of epithelial progenitor cells, while other regions remained denuded or squamated, resulting in fibroblast proliferation and peribronchial collagen deposition associated with upregulation of the fibrogenic cytokines transforming growth factor-β and connective tissue growth factor. The total collagen content of the lung assessed by measurement of the hydroxyproline content was also increased after repeated exposure to naphthalene. These results lend support to the relevance of repeated injury of airway epithelial cells as a trigger for resting fibroblast proliferation and airway fibrosis. This model of airway fibrosis is simple and easy to reproduce, and may be expected to advance our understanding of the pathogenesis and potential treatment of airway fibrotic disorders.

Porcine Splenic Hydrolysate has Antioxidant Activity in vivo and in vitro

The antioxidant capacity of porcine splenic hydrolysate (PSH) was studied in vitro and in vivo. Peptide hydrolysates were prepared, using the proteolytic enzyme Alcalase^®. The molecular weights of PSH were 37,666, 10,673, 6,029, and 2,918 g/mol. Rats were fed a 5% (w/v) PSH diet, instead of a casein diet, for 4 wk. The food intake, body weight gain, and liver weight of rats in the PSH group were similar to those in the control (CONT) group. There were no differences in the serum total cholesterol, triglyceride, total protein, or albumin levels between PSH and CONT groups. However, the level of in vivo hepatic lipid peroxidation in PSH group was significantly lower than that in CONT. In vivo hepatic catalase and glutathione peroxidase activities in the PSH group were significantly higher than those in the control group. The in vitro protein digestibility of PSH was lower than that of casein. The in vitro trolox equivalent antioxidant capacity of PSH was significantly higher than that of the peptide hydrolysate from casein. The in vitro radical scavenging activities of PSH were significantly higher than those of the peptide hydrolysate from casein. The present findings suggest that porcine splenic peptides improve the antioxidant status in rats by enhancing hepatic catalase and GSH-Px activities, and indicate a potential mechanism of radical scavenging activity during gastrointestinal passage.

Survivability and abiotic reactions of selected amino acids in different hydrothermal system simulators

We tested the stability and reaction of several amino acids using hydrothermal system simulators: an autoclave and two kinds of flow reactors at 200-250 °C. This study generally showed that there is a variation in the individual amino acids survivability in the simulators. This is mainly attributed to the following factors; heat time, cold quenching exposure, metal ions and also silica. We observed that, in a rapid heating flow reactor, high aggregation and/or condensation of amino acids could occur even during a heat exposure of 2 min. We also monitored their stability in a reflow-type of simulator for 120 min at 20 min intervals. The non-hydrolyzed and hydrolyzed samples for this system showed a similar degradation only in the absence of metal ions.

Bioanalytical LC separation techniques for quantitative analysis of free amino acids in human plasma

The quantitative analysis of free amino acids in human plasma has become an important and essential analysis parameter in different areas of life sciences. Free amino acid concentrations in human plasma samples are generally determined by means of GC or LC after chemical derivatization followed by UV, fluorescent or MS detection of the amino acid derivatives. Derivatization of free amino acids is done either pre- or post-column, and the amino acid derivatives obtained posess improved chromatographic behavior, increased detection sensitivity and selectivity compared with non-derivatized free amino acids. This work gives an overview of different chemical derivatization methods applied and their liquid separation techniques in bioanalytical assays for quantitative free amino acid analysis in human plasma samples. Important plasma preparation procedures, pre- and post-column derivatization, and different LC separation techniques are presented.

Cell volume regulation in the perfused liver of a freshwater air-breathing cat fish Clarias batrachus under aniso-osmotic conditions: roles of inorganic ions and taurine

The roles of various inorganic ions and taurine, an organic osmolyte, in cell volume regulation were investigated in the perfused liver of a freshwater air-breathing catfish Clarias batrachus under aniso-osmotic conditions. There was a transient increase and decrease of liver cell volume following hypotonic (-80 mOsmol/l) and hypertonic (+80 mOsmol/l) exposures,respectively, which gradually decreased/increased near to the control level due to release/uptake of water within a period of 25-30 min. Liver volume decrease was accompanied by enhanced efflux of K+ (9.45 +/- 0.54 micromol/g liver) due to activation of Ba(2+)- and quinidine-sensitive K(+) channel, and to a lesser extent due to enhanced efflux of Cl(-) (4.35+/- 0.25 micromol/g liver) and Na+ (3.68+/- 0.37 micromol/g liver). Conversely, upon hypertonic exposure, there was amiloride-and ouabain-sensitive uptake of K+ (9.78+/- 0.65 micromol/g liver), and also Cl(-) (3.72 +/- 0.25 micromol/g liver).The alkalization/acidification of the liver effluents under hypo-/hypertonicity was mainly due to movement of various ions during volume regulatory processes. Taurine,an important organic osmolyte, appears also to play a very important role in hepatocyte cell volume regulation in the walking catfish as evidenced by the fact that hypo- and hyper-osmolarity caused transient efflux (5.68 +/- 0.38 micromol/g liver) and uptake (6.38 +/- 0.45 micromol/g liver) of taurine, respectively. The taurine efflux was sensitive to 4,4' -di-isothiocyanatostilbene-2,2'-disulphonic acid (DIDS, an anion channel blocker), but the uptake was insensitive to DIDS, thus indicating that the release and uptake of taurine during volume regulatory processes are unidirectional. Although the liver of walking catfish possesses the RVD and RVI mechanisms, it is to be noted that liver cells remain partly swollen and shrunken during anisotonic exposures,thereby possibly causing various volume-sensitive metabolic changes in the liver as reported earlier.

A local GABAergic system within rat trigeminal ganglion cells

We investigated the GABAergic system within the Sprague-Dawley rat (2-3-weeks old) trigeminal ganglion (TG). Reverse transcription-polymerase chain reaction (RT-PCR) analysis revealed expression of glutamate decarboxylase (GAD) 65 and GAD67 mRNAs and mRNAs encoding GABA(A) receptor subunits alpha1-6, beta1-3, gamma1-3, and delta. In situ hybridization revealed that GAD65 and GAD67 mRNAs were expressed in neuronal cell bodies but not satellite cells. Immunohistochemical analysis showed that only GAD65 was expressed in all neuronal cell bodies, and approximately 70% of all neurons exhibited GABA immunoreactivity. Satellite cells were strongly immunopositive for GABA. GABA(A) receptor alpha1, alpha5, beta2/3 and gamma1/2/3 subunit immunoreactivities were observed in the majority of neurons, but no immunoreactivity for alpha2 was observed. Two types of cells were identified in TG based on cell size and morphology, type A and B. The percentage of cells expressing alpha3, alpha4, alpha6, and delta subunits appeared to be dependent on cell size, as delta and alpha6 expression were only observed in small (B-type) neurons. In whole-cell patch clamp experiments, GABA application induced inward Cl- currents in all neurons examined. The EC50 for GABA varied from 5.3 to 240 microm, and the Hill Coefficient (nH) varied between 0.98 and 2.6 at -60 mV. We found that GABA was released from TG cells by increasing extracellular K+ concentration to 100 mm. We speculate that GABA acts as a nonsynaptically released diffusible neurotransmitter, which may modulate somatic inhibition of neurons within the TG.

Source identification of Indian opium based on chromatographic fingerprinting of amino acids

Total and free pool of amino acids was determined in Indian opium samples using liquid chromatography (LC) with post-column opthalaldehyde derivatization followed by its fluorimetric detection. The limit of detection (LOD) was found to be in the range of 2-10 pmol with a signal to noise ratio of 3:1 and limit of quantitation (LOQ) was found to be in the range of 7-31 pmol with a signal to noise ratio of 10:1. The recovery of amino acids was found to be in the range of 86-103%. A total of 124 Indian opium samples were collected from the states of Madhya Pradesh (MP), Uttar Pradesh (UP) and Rajasthan (Raj), covering 14 licit opium growing divisions of India were chromatographically fingerprinted for the presence of various amino acids. The amino acids identified in sample hydrosylate included D, T, S, S, G, A, V, I, L, Y, F, H, K and R, while the analysis of free pool of amino acids (80% aqueous ethanol extract) indicated the presence of D, T, S, E, A, V, I, L, Y, H, K respectively. Multiple discriminant analysis was applied to the quantitative total amino acid data to determine an optimal classifier in order to evaluate the source of Indian opium. The foremost amino acid variables that accounted for the true discrimination were identified as D, E, G, A, F and K in evaluating the geographical origin of Indian opium and the predictive value based on the discriminant analysis was found to be 90% in relation to the source of opium samples. Chemometrics performed with amino acid analytical data was used successfully in discriminating the licit opium growing divisions of India into three major groups, viz. groups I, II and III. The methodology developed may find wide application in forensic analysis.

Dietary whey protein modulates liver glycogen level and glycoregulatory enzyme activities in exercise-trained rats

This study compared the effects of dietary whey protein with dietary casein or soy protein on glycogen storage and glycoregulatory enzyme activities in the liver of sedentary and exercise-trained rats. Male Sprague-Dawley rats (ca. 130 g) were divided into one sedentary and three exercise-trained groups, with eight animals in each group. Casein was provided as the source of dietary protein in the sedentary group while the exercise-trained groups were fed casein, whey, or soy protein. Rats in the exercise-trained groups ran for 30 mins/day, 4 days/week on a motor-driven treadmill. In the exercise-trained rats, animals fed whey protein had higher liver glycogen content than animals in the other two diet groups. Glucokinase activity was significantly higher in rats fed whey protein compared to that in rats fed soy protein, while glucose 6-phosphatase activity was significantly decreased in animals on the whey protein diet compared with those the other two diets. Although 6-phospho-fructokinase activity was significantly lower in the whey protein group than in the soy protein group, we found that fructose 1,6-bisphosphatase activity was significantly higher in the whey group compared with either the casein or soy groups. Pyruvate kinase activity in rats fed the casein diet was significantly higher than in rats fed either the whey or soy protein diets. In addition, hepatic alanine aminotransferase activity and serum alanine level were also increased in the whey protein group compared with the casein or soy protein groups. Taken together, these results demonstrate that the whey protein diet in exercise-trained rats results in significantly higher levels of liver glycogen, because of the combined effects of regulation of rate limiting glycolytic and gluconeogenic enzyme activities and activation of glycogenesis from alanine via alanine amino-transferase.

Anthelmintic efficacy of genistein, the active principle of Flemingia vestita (Fabaceae): alterations in the free amino acid pool and ammonia levels in the fluke, Fasciolopsis buski

The crude root-peel extract of Flemingia vestita, its active principle genistein and the reference flukicide oxyclozanide were tested against Fasciolopsis buski, the giant intestinal trematode. The amino acid composition of F. buski was demonstrated using HPLC and it was observed that the free amino acid (FAA) pool of the control worm consisted of aspartate, threonine, serine, glutamic acid, glutamine, proline, glycine, alanine, valine, methionine, isoleucine, leucine, tyrosine, lysine, histidine, arginine, phosphoserine, taurine, citrulline, ornithine, beta-alanine, and gamma-amino butyric acid (GABA). Of the amino acids detected valine was found to be the maximum in quantitative analysis. In qualitative analysis the FAA pool of the parasites under various treatments remained same as that of the control; however, quantitatively the level of various FAAs in the parasite was significantly affected. The treated parasites showed a marked decrease in the levels of arginine, ornithine, tyrosine, leucine, isoleucine, valine, alanine, glycine, proline, serine, threonine, and taurine following treatment with 20 mg/ml of crude peel extract, 0.5 mg/ml of genistein and 20 mg/ml of the reference drug, though an increase in the levels of glutamic acid, glutamine, phosphoserine, citrulline and GABA was noticeable. Enhanced levels of GABA and citrulline under the influence of genistein may be implicated in alterations of nitric oxide release and consequent neurological change (e.g. paralysis) in the parasite. Ammonia in the tissue homogenate as well as in the incubation medium showed a quantitative increase compared to the controls after treatment with the various test materials. The ammonia level increased by 40.7%, 66.4% and 18.16% in treatments with F. vestita, genistein and oxyclozanide, respectively, at the mentioned dosages. The changes in the levels of the amino acids and nitrogen components post treatment suggest that the amino acid metabolism in the parasite may have been altered under the influence of the test materials.

Possible role of L-carnosine in the regulation of blood glucose through controlling autonomic nerves

Mammalian muscles synthesize L-carnosine, but its roles were unknown. Previously, we found in rats that the administration of a certain amount of L-carnosine elicited an inhibition of the hyperglycemia induced by the injection of 2-deoxy-D-glucose (2DG) into the lateral cerebral ventricle (LCV), and that intravenous injection of L-carnosine inhibited sympathetic nerves and facilitated the parasympathetic nerve. Moreover, the suppressive effect of L-carnosine on the hyperglycemia induced by 2DG was eliminated by thioperamide, a histaminergic H3 receptor. These findings suggested that L-carnosine might control the blood glucose level through regulating autonomic nerves via H3 receptor. To further clarify the function of L-carnosine, we examined its role in the control of the blood glucose. In this experiment, the following results were observed in rats: (i) A certain amount (0.01% or 0.001%) but not a larger amount (0.1%) of L-carnosine given as a diet suppressed the hyperglycemia induced by LCV-injection of 2DG (2DG-hyperglycemia); (ii) LCV-injection but not the injection into the intraperitoneal space (IP) of a certain amount of L-histidine suppressed the 2DG-hyperglycemia; (iii) treatments of diphenhydramine, an H1 antagonist, and alpha-fluoromethylhistidine, an inhibitor of histamine-synthesizing enzyme, reduced the 2DG-hyperglycemia; (iv) the plasma L-carnosine concentration and carnosinase activity showed daily changes; (v) the plasma L-carnosine concentration was significantly lower in the streptozotocin-diabetic rats; (vi) exercise by a running wheel tended to increase carnosine synthase activity in the gastrocnemius muscle and elevated the plasma L-carnosine concentration in the dark (active) period, and enhanced the plasma carnosinase activity in the light period; (vii) IP-injection of certain amount of L-carnosine stimulated the feeding response to IP-injection of 2DG. These findings suggest a possibility that L-carnosine released from muscles due to exercise functions to reduce the blood glucose level through the regulation of the autonomic nerves.

Antioxidant activity of peptides obtained from porcine myofibrillar proteins by protease treatment

Hydrolysates obtained from porcine myofibrillar proteins by protease treatment (papain or actinase E) exhibited high antioxidant activity in a linolenic acid peroxidation system induced by Fe(2+). Hydrolysates produced by both papain and actinase E showed higher activities at pH 7.1 than at pH 5.4. The antioxidant activity of the papain hydrolysate was almost the same as that of vitamin E at pH 7.0. These hydrolysates possessed 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity and chelating activity toward metal ions. Antioxidant peptides were separated from the papain hydrolysate by ion exchange chromatography. The acidic fraction obtained by this method exhibited higher activity than the neutral or basic fractions. Antioxidant peptides in the acidic fraction were isolated by high-performance liquid chromatography on an ODS column and shown to possess the structures DSGVT, IEAEGE, DAQEKLE, EELDNALN, and VPSIDDQEELM. The DAQEKLE peptide showed the highest activity among these peptides.

Repression of bleomycin-induced pneumopathy by TNF

Idiopathic pulmonary fibrosis is a chronic inflammatory lung disease with interstitial fibrosis. As a potent proinflammatory cytokine, TNF has been suggested to play critical roles in the pathogenesis of the human disease and its animal model, bleomycin-induced pneumopathy. However, studies using TNF-deficient mice have demonstrated that TNF also has an anti-inflammatory function. To determine the role of TNF in pulmonary inflammation induced by bleomycin, we injected bleomycin intratracheally into TNF-deficient mice. In this study, we demonstrated persistent and intense inflammation in TNF-deficient mice due to reduced apoptosis of inflammatory cells. We also showed that in TNF-deficient mice, challenge via airways with murine, but not human rTNF, efficiently eliminated inflammatory cells from the bronchoalveolar space by apoptosis, and thus promoted tissue repair of damaged lungs. Contrary to previous reports that showed that TNF was a central mediator of pulmonary inflammation, we have demonstrated that TNF is essential for repressing pulmonary inflammation in bleomycin-induced pneumopathy.

Role of amino acid metabolism in an air-breathing catfish, Clarias batrachus in response to exposure to a high concentration of exogenous ammonia

The air-breathing ureogenic walking catfish (Clarias batrachus) faces various environmental constraints throughout the year leading to the problem of accumulation of toxic ammonia. In the present study, the possible role of conversion of accumulated ammonia to various non-essential free amino acids (FAAs) was tested in this fish under hyper-ammonia stress caused by exposing the fish at 25 mM NH(4)Cl for 7 days. Significant accumulation of ammonia of approximately two- to threefold was observed in different tissues (except in the brain), which was accompanied with the significant accumulation of non-essential FAAs in the NH(4)Cl-exposed fish. There was approximately two- to threefold increase of non-essential FAAs in different tissues and in the plasma of the NH(4)Cl-exposed fish compared to the control fish after 7 days of exposure, which was mainly attributable to the increase of Asp, Ala, Gly, Glu, Gln and taurine (Tau) concentrations in general, with certain tissue-specific variations. This was also accompanied with significant increase of activity of certain amino acid metabolism-related enzymes such as the glutamine synthetase (approx. two- to threefold), glutamate dehydrogenase (ammonia utilizing direction) (approx. twofold), aspartate and alanine aminotransaminases (approx. twofold) mainly in the liver, kidney and muscle of the NH(4)Cl-exposed fish. Thus, it appears that the walking catfish has the capacity of active conversion of accumulated ammonia to non-essential FAAs under condition of high concentrations of external ammonia. However, the increase of urea excretion rate due to active conversion of ammonia to urea via the induced urea cycle appears to be quantitatively much more important pathway than the increase of tissue levels of FAAs in dealing with a severe ammonia load.

Effects of hormone replacement therapy and methylenetetrahydrofolate reductase polymorphism on plasma folate and homocysteine levels in postmenopausal Japanese women

OBJECTIVE

To evaluate the relationships among the methylenetetrahydrofolate reductase (MTHFR) polymorphism, plasma folate, total homocysteine (Hcy) levels, lipids, and the reduction of Hcy levels resulting from hormone replacement therapy (HRT).

DESIGN

Clinical study.

SETTING

Outpatient department of obstetrics and gynecology in a general hospital.

PATIENT(S)

Two hundred seventeen postmenopausal Japanese women.

INTERVENTION(S)

Of the 217 women, 172 patients were under continuous treatment with oral conjugated equine estrogen and medroxyprogesteron acetate.

MAIN OUTCOME MEASURE(S)

Fasting Hcy, folate, methionine, lipids, and apolipoproteins were measured before and after 3 months of HRT.

RESULT(S)

The plasma Hcy concentration was significantly higher in the low folate than in the high-folate group only in patients with the homozygous (T/T) mutant. Plasma Hcy concentrations were significantly correlated with age (R = 0.64, P=.02) or years since menopause (R = 0.73, P=.02) only in the low-folate group with T/T. The plasma Hcy concentration decreased significantly in all genotypes after 3 months of HRT, but the levels of serum folate and methionine remained unchanged.

CONCLUSION(S)

The MTHFR polymorphism was associated with a higher Hcy concentration, and this association was related to the serum folate level. Hormone replacement therapy reduced the plasma Hcy concentration independently of the MTHFR polymorphism.

Effect of clonazepam treatment on antipsychotic drug-induced Meige syndrome and changes in plasma levels of GABA, HVA, and MHPG during treatment

We demonstrated the effect of clonazepam (2 mg/day) on Meige syndrome in two schizophrenic patients under continuous treatment with antipsychotic drugs, and changes in the plasma levels of gamma-aminobutyric acid (GABA), homovanillic acid (HVA), and 3-methoxy-4-hydroxyphenylglycol (MHPG) in these cases. The plasma levels of HVA and MHPG during treatment with clonazepam were decreased in the responder, while not changed in the non-responder to clonazepam. A difference between the responder and the non-responder was not found in the plasma GABA levels. These results suggest that hyperactivities of the central dopaminergic and noradrenergic neurones are involved in the pathophysiology of Meige syndrome.

Antiinflammatory and antiarteriosclerotic actions of HMG-CoA reductase inhibitors in a rat model of chronic inhibition of nitric oxide synthesis

Recent studies suggest that some of the beneficial effects of 3-hydroxyl-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) may be due to their cholesterol-lowering independent effects on the blood vessels. Chronic inhibition of endothelial nitric oxide (NO) synthesis by oral administration of N(omega)-nitro-L-arginine methyl ester (L-NAME) to rats induces early vascular inflammation as well as subsequent arteriosclerosis. The aim of the study is to test whether treatment with statins attenuates such arteriosclerotic changes through their cholesterol-lowering independent effects. We investigated the effect of statins (pravastatin and cerivastatin) on the arteriosclerotic changes in the rat model. We found that treatment with statins did not affect serum lipid levels but markedly inhibited the L-NAME-induced vascular inflammation and arteriosclerosis. Treatment with statins augmented endothelial NO synthase activity in L-NAME-treated rats. We also found the L-NAME induced increase in Rho membrane translocation in hearts and its prevention by statins. Such vasculoprotective effects of statins were suppressed by the higher dose of L-NAME. In summary, in this study, we found that statins such as pravastatin and cerivastatin inhibited vascular inflammation and arteriosclerosis through their lipid-lowering independent actions in this model. Such antiarteriosclerotic effects may involve the increase in endothelial NO synthase activity and the inhibition of Rho activity.

Decreased plasma and cerebrospinal fluid glutamine concentrations in a patient with bialaphos poisoning

A 47-year-old Japanese woman undergoing maintenance hemodialysis (HD) was admitted to our hospital because of poisoning with the herbicide bialaphos. Respiratory arrest and loss of consciousness ensued rapidly, accompanied by convulsions and nystagmus. Treatment with HD and direct hemoperfusion, followed by HD alone, effectively removed bialaphos and its chief toxic metabolite (L-AMPB) from the circulation (bialaphos decreased from 0.33 to < 0.05 microg/ml and L-AMPB from 14 to 0.86 microg/ml). The glutamate concentration improved gradually after the removal of bialaphos and L-AMPB from plasma (plasma glutamate concentration: 250.4 nmol/l on day 5 to 120.6 nmol/l on day 26). Decreased glutamine concentration in cerebrospinal fluid was demonstrated for the first time as well as in plasma, indicating glutamine synthetase inhibition not only in plants but also in humans by bialaphos poisoning.

Pirfenidone inhibits dimethylnitrosamine-induced hepatic fibrosis in rats

1. In the present study, we investigated the preventive effects of pirfenidone (PFD), an antifibrotic agent, on experimental hepatic fibrosis induced by dimethylnitrosamine (DMN) in rats. 2. Treatment with DMN caused a significant decrease in bodyweight and liver weight. Oral PFD (500 mg/kg daily for 4 weeks) essentially prevented this DMN-induced loss in bodyweight and tended to suppress the loss in liver weight. There were no significant differences in liver weight and serum L-alanine aminotransferase levels between PFD-treated and -untreated groups. Pirfenidone has no major side effects in vivo. 3. Pirfenidone suppressed the induction of hepatic fibrosis determined by histological evaluation and reduced hepatic hydroxyproline levels. Expression of mRNA for type I collagen and transforming growth factor-beta in the liver was also suppressed by PFD treatment. 4. Because hepatic stellate cells (HSC) are the major cellular source of extracellular matrix in hepatic fibrosis, we examined the effects of PFD on type I collagen production in vitro using rat primary HSC cultures. Pirfenidone inhibited collagen production in HSC culture in a dose-dependent manner. 5. These results demonstrate that the inhibitory effects of PFD against hepatic fibrosis may be due, at least in part, to blockade of collagen production by HSC and suggest that PFD may be potentially useful in the prevention of the development of hepatic fibrosis.

Derivatization and chromatographic behavior of the o-phthaldialdehyde amino acid derivatives obtained with various SH-group-containing additives

An overview is presented of HPLC methods currently in use to determine amino acids as their o-phthaldialdyde derivatives in the presence of various SH-group-containing additives. Crucial points that proved to influence the stability of the amino acid OPA derivatives have been discussed in detail: (i) the mol ratios of the OPA-SH-group-containing additive amino acid; (ii) the preparation and storage conditions of the OPA reagents; (iii) the optimum pH conditions for the interactions and elutions; (iv) the behavior of the, believed to be, less stable amino acids, such as glycine, beta-alanine, gamma-aminobutyric acid, histidine, ornithine and lysine.

A selective ROCK inhibitor, Y27632, prevents dimethylnitrosamine-induced hepatic fibrosis in rats

BACKGROUND

p160ROCK is a direct Rho target which mediates Rho-induced assembly of focal adhesions and stress fibers. We previously reported that Rho signaling pathways are involved in the activation of hepatic stellate cells (HSC) in vitro. The aim of the present study was to test the hypothesis that an inhibitor specific for p160ROCK (Y27632) could prevent experimental hepatic fibrosis induced by dimethylnitrosamine (DMN) in rats.

METHODS

Y27632 was given orally at 30 mg/kg daily for 4 weeks after the first injection of DMN. The degree of fibrosis was evaluated by image analysis and also by measurements of collagen and hydroxyproline content in the liver. The expression of alpha-smooth muscle actin (alpha-SMA) in the liver and in the primary cultured HSC was also evaluated. Semi-quantitative RT-PCR was performed to evaluate the expression of type I collagen mRNA in the liver.

RESULTS

Y27632 treatment significantly decreased the occurrence of DMN-induced hepatic fibrosis and reduced the collagen and hydroxyproline content and alpha-SMA expression in the liver. The expression of alpha-SMA in HSC was also suppressed in vitro.

CONCLUSIONS

These findings indicate that inhibitors of the Rho-ROCK pathway might be useful therapeutically in hepatic fibrosis.

The Fas/Fas-ligand system is not required for bleomycin-induced pulmonary fibrosis in mice

Recent studies suggest that Fas-Fas-ligand (FasL) interactions play an important role in the development of lung injury and fibrosis. However, evidence to support this concept is still indirect. To determine whether Fas-FasL interaction is required for the development of bleomycin-induced pulmonary fibrosis in mice, we used Fas-deficient (lpr) and FasL-deficient (gld ) mice as animal models. After intratracheal instillation of bleomycin, we examined the lungs of mice through bronchoalveolar lavage, histologic studies, DNA nick-end labeling, and hydroxyproline assay. The development of cellular infiltrates, bronchiolar and alveolar epithelial apoptosis, and fibrosis following bleomycin instillation in the lungs in lpr mice and gld mice was similar to their development in wild-type mice. The results of this study show that bleomycin-induced pulmonary fibrosis does not require Fas-FasL interaction, and that epithelial cell apoptosis after bleomycin exposure is mediated by Fas-independent pathways.

The beneficial effects of recombinant human insulin-like growth factor-I (IGF-I) on wound healing in severely wounded senescent mice

The effects of recombinant insulin-like growth factor I (rIGF-I) on wound healing were tested using senescent and young BDF-1 mice, aged 108 weeks and 10 weeks, respectively. After inflicting a full thickness dermal burn encompassing 15% of the body surface, a skin incision, 2 cm in length, was made in the back. A silicone tube containing a piece of polyvinyl sponge was then implanted into a subcutaneous pocket in the flank to collect body fluid. An osmotic pump was buried in the abdominal subcutaneous tissue for the continuous infusion of rIGF-I, the control being treated with the solvent of IGF-I, physiological saline, only. The administration of IGF-I produced favorable effects on wound healing in the senescent mice, shown by enhanced tensile strength and an elevated concentration in the hydroxyproline of the polyvinyl sponge content. The IGF-I-treated severely wounded senescent mice healed better than their counterparts and their skeletal muscles contained more glutamine. Furthermore, they showed more enhanced cutaneous hypersensitivity towards dinitrofluorobenzene than the controls, suggesting an enhanced grade of cellular immunity. There were no conspicuous differences between the two groups of young mice. These data may suggest the beneficial effects of rIGF-I on wound healing, especially in geriatric surgery.

Retention/quantitation properties of the o-phthaldialdehyde-3-mercaptopropionic acid and the o-phthaldialdehyde-N-acetyl-L-cysteine amino acid derivatives in reversed-phase high-performance liquid chromatography

The separation/identification of 25 amino acids as their o-phthaldialdehyde-3-mercaptopropionic acid (OPA/MPA) and o-phthaldialdehyde-N-acetyl-L-cysteine (OPA/NAC) derivatives have been optimized [paying particular attention to those amino acids which elute with more than one derivative (glycine, histidine, gamma-aminobutyric acid, beta-alanine, ornithine, lysine) and that are expected to be present in apples in their free form]. Optimum separation conditions are reported on six reversed-phase columns: Nucleosil 3 and 5 microm, 150(+20 guard)x4.0 mm; Gromsil 3 microm, 150(+10 guard)x4.0 mm; Hypersil 5 microm, 150(+20 guard)x4.0 mm and 200(+20 guard)x4.0 mm; and Hypersil 3 microm, 150(+20 guard)x4.0 mm. Elutions were followed, simultaneously, with photodiode array and fluorescence detectors connected in line. Optimization studies carried out in model solutions as a function of temperature (30-55 degrees C) and eluent flow-rate (0.8-2.5 mL/min) demonstrated that optimum resolutions are obtained with the highest flow-rate applicable (remaining on the safe side with a column pressure of << 3500 p.s.i.; 1 p.s.i.=6894.76 Pa) in the temperature range 30-50 degrees C. Twenty-five amino acids, eluting in 31 separate, characteristic derivatives, were determined on all six columns (the main component, asparagine, present in overwhelming excess, together with the minor constituents glutamine, beta-alanine, gamma-aminobutyric acid, homoserine, and homoarginine). Optimum conditions in the case of both derivatives were obtained on the same type of column (Hypersil, 5 microm), as follows: for the OPA/MPA amino acids with programmed flow-rate [1.3-2.3 ml/min; column, 200(+20 guard)x4 mm], at 50 degrees C, while, for the OPA/NAC amino acids at 2.1 ml/min flow rate, at 30 degrees C [column, 150(+20 guard)x4 mm], with 40 and 37 min run times, including equilibration. Responses of the corresponding amino acids proved to be independent of the column used; reproducibility in the concentration range 6-12,000 pmol, related to the injected amount of amino acids, was <3.4% RSD (average relative standard deviation percentage). The utility of the protocol was demonstrated in the quantitation of the free amino acid content of five apple varieties (Jonagored, Idared, Jonica, Florina, Freedom) on various harvesting dates and after different storage times. Derivatization of the apple pulp was performed with filtered samples, applying any special isolation processes.

Changes in free amino acid synthesis in the perfused liver of an air-breathing walking catfish, Clarias batrachus infused with ammonium chloride: a strategy to adapt under hyperammonia stress

The changes in the free amino acid (FAA) levels, the rate of efflux of FAAs from the perfused liver, and the activity of some enzymes related to amino acid metabolism such as glutamate dehydrogenase (GDH, both reductive amination and oxidative deamination), glutamine synthetase (GS), aspartate aminotransferase (AST), and alanine aminotransferase (ALT) were studied in the liver of a freshwater air-breathing teleost, the walking catfish, Clarias batrachus, perfused with 5 and 10 mM NH(4)Cl. The level of the various non-essential FAAs increased significantly, with a total increase of about 150%, which was accompanied by a significant increase of both ammonia and urea-N in the perfused liver both with 5 and 10 mM NH(4)Cl. The rate of efflux of these non-essential FAAs from the perfused liver also increased significantly with a total increase of about 115% and 160% at 5 and 10 mM NH(4)Cl, respectively. The activity of the mentioned amino acid metabolism-related enzymes in the perfused liver also got stimulated, except for GDH in the ammonia forming direction and ALT, under a higher ammonia load. The activity (both tissue and specific) of GDH in the glutamate forming direction increased maximally, followed by AST and GS in a decreasing order. Owing to these physiological adaptive strategies related to amino acid metabolism along with the presence of a functional and regulatory urea cycle (reported earlier), it is believed that this catfish is able to survive in very high ambient ammonia or in the air or in the mud during habitat drying.

Long-term vascular effects of Nomega-nitro-L-arginine methyl ester are not soley mediated by inhibition of endothelial nitric oxide synthesis in the rat mesenteric artery

Nomega-nitro-L-arginine methyl ester (L-NAME), one of the synthetic L-arginine analogues with inhibitory effects of nitric oxide (NO) synthesis, is now widely used to examine the role of NO in various organs. We and others demonstrated that long-term treatment with L-NAME causes hypertension and cardiovascular lesions (perivascular fibrosis and medial thickening), especially at microvascular levels. However, convincing evidence is still lacking that these long-term cardiovascular effects of L-NAME are solely mediated by the inhibition of the synthesis of endothelium-derived NO (EDNO). This study was thus designed to better understand the effects of long-term treatment with L-NAME with special reference to EDNO synthesis. Male Wister-Kyoto rats were orally administered L-NAME for 8 weeks. Blood pressure significantly increased at 3 days and 1 and 8 weeks of the treatment. Endothelium-dependent relaxations to acetylcholine (ACh) of the aorta were reduced 3 days after the treatment, recovered at 1 week, and again reduced at 8 weeks, whereas the relaxations of the small mesenteric artery were unaltered throughout the experimental periods. At 8 weeks, indomethacin-sensitive, endothelium-dependent contractions to ACh were noted. The relative contributions of NO and endothelium-derived hyperpolarizing factor also were unchanged. Citrulline assay demonstrated that substantial levels of constitutive NO synthase activity remained in the aorta during the experiments. The long-term treatment with L-NAME caused perivascular fibrosis and medial thickening, not only in the aorta but also in the mesenteric artery. These results suggest that mechanism(s) other than simple inhibition of EDNO synthesis is involved in the long-term cardiovascular effects of L-NAME in the rat mesenteric artery.

Trehalose can be used as a parenteral saccharide source in rabbits

Trehalose is a saccharide that possesses no reducing group and so has possible use in parenteral nutrition, especially because it can be stored with amino acids without undergoing the Maillard reaction. To evaluate this possibility, a series of experiments were conducted. The activity of trehalase, an enzyme that metabolizes trehalose to glucose, was measured in rabbit serum and kidney. Conversion of trehalose to glucose and excretion of trehalose in the urine were measured in rabbits administered 10% trehalose intravenously. The effects on nutritional indices as indicators of its use as an energy source were also measured in rabbits infused with 8.23 g.kg-1.d-1 (4. 12 g.kg-1 on d 1) of trehalose for 5 d. Trehalase activity resembled maltase activity, both being high in the renal cortex (2.04 +/- 0.71 and 2.93 +/- 0.26 micromol.g-1.min-1, respectively), weak in the medulla, and undetectable in the serum. Serum glucose and insulin concentrations were increased significantly by trehalose infusion. Significant elevations were observed in serum glucose but not insulin levels by maltose infusion. On the other hand, urinary excretion of trehalose (1.1 +/- 2.1% of dose) was significantly lower than that of maltose (10.1 +/- 4.9% of dose). Similar effects of trehalose and maltose infusions as seen in normal rabbits occurred in rabbits with alloxan diabetes (urinary excretion rate, 3. 8 +/- 3.0% of the infused trehalose dose and 35.6 +/- 9.7% of the infused maltose dose). Nitrogen balance was positive in the trehalose- and glucose-infused normal rabbits with significant difference from the control group infused with saline, suggesting that trehalose was used as an energy source. These results suggest that trehalose has the potential for use as a saccharide source for parenteral nutrition.

A comparison of plasma glutamine concentration in athletes from different sports

PURPOSES

The purposes of the current investigation were to compare resting plasma glutamine concentration in athletes from different sports and to determine the relationship between resting plasma glutamine concentration and dietary protein intake.

METHODS

Resting plasma glutamine concentration was measured in five groups of eight distance runners, competitive swimmers, cyclists, powerlifters, and nonathletes. Dietary protein intake of each subject was measured (g.d-1 and g.kg-1.d-1).

RESULTS

Plasma glutamine concentration was significantly different between sports (P = 0.000, ANOVA) with mean plasma glutamine concentration of cyclists significantly higher than in all other groups, and mean plasma glutamine concentration of powerlifters and swimmers significantly lower than in cyclists and nonathletes (P < 0.05, post hoc analysis). There was no significant relationship between plasma glutamine concentration and total dietary protein intake when expressed as g.d-1 (r = 0.11, P > 0.05); however, plasma glutamine concentration and dietary protein relative to body mass (g.kg-1.d-1) were significantly inversely correlated (r = -0.37, P = 0.007).

CONCLUSIONS

These data suggest that resting plasma glutamine concentration may vary between sports, possibly due to metabolic demands of the different sports; dietary factors may also affect plasma glutamine concentration.

High-performance liquid chromatographic method for rapid and highly sensitive determination of histidine using postcolumn fluorescence detection with o-phthaldialdehyde

A high-performance liquid chromatographic method was developed for the rapid and sensitive determination of histidine. The method is based on separation by reversed-phase ion-pair chromatography followed by highly selective fluorescence derivatization of histidine with o-phthaldialdehyde. A linear calibration curve was obtained over the range of 0.25-200 pmol per injection (10 microl) with the coefficient of variation of 0.9% at 2 pmol (n=10) and with the detection limit (SIN=8) of 25 fmol. The method was applicable to the assay of histidine in human serum. Serum histidine values obtained by the present method were in good agreement with values obtained with an amino acid analyzer.

Single-column high-performance liquid chromatographic-fluorescence detection of immature, mature, and senescent cross-links of collagen

A high-performance liquid chromatographic-fluorescence detection method of reducible (immature) and nonreducible (mature and senescent) cross-links of collagen was established without the use of a radioisotope and preliminary fractionation step. This method used a gradient elution procedure of sodium citrate buffer containing 7% ethanol. The reducible cross-links (dihydroxylysinonorleucine, hydroxylysinonorleucine, and lysinonorleucine) and nonreducible cross-link (histidinohydroxylysinonorleucine) were detected by O-phthalaldehyde derivatization with the postcolumn method, whereas other nonreducible cross-links (pyridinoline, deoxypyridinoline, and pentosidine) were detected by natural fluorescence. The linear ranges of contents of the O-phthalaldehyde derivative cross-links and the natural fluorescent nonreducible cross-links were 20-600, 5-500 (pyridinoline, deoxypyridinoline), and 0.2-20 pmol (pentosidine), respectively. Tissue containing 1-2 mg dry wt of collagen was adequate for duplicate analyses of the reducible and nonreducible cross-links. An equivalent of 0.25 mg of hydrolyzed collagen could be analyzed by this HPLC system. Using this system, age-related changes in the cross-links of collagen from human connective tissues were also investigated.

The effect of cyclosporin A administration on bone metabolism in the rat evaluated by biochemical markers

We investigated the effects of cyclosporin A (CsA), an immunosuppressive agent, on bone remodeling in 6 rats compared to 6 controls, using a histomorphometric technique and biochemical markers for bone metabolism. With an oral daily dose of 15 mg CsA/kg of body weight for 28 days, the trabecular bone volume in CsA administered rats was significantly lower than that in control rats, which indicates bone loss in CsA rats. In CsA rats, bone resorption increased, and urinary pyridinoline (Pyr) significantly increased on day 28 compared with control rats. In contrast, bone formation assessed by serum osteocalcin and osteoid volume had no remarkable changes. These results suggest that administration of CsA for 28 days induces bone loss due to uncoupling between bone resorption and bone formation.