Nutritional evaluation of protein, phosphorus, calcium and magnesium bioavailability from lupin (Lupinus albus var. multolupa)-based diets in growing rats: effect of alpha-galactoside oligosaccharide extraction and phytase supplementation.

Br J Nutr. 2006 Jun;95(6):1102-11

Authors: Porres JM, Aranda P, López-Jurado M, Urbano G

The nutritional composition of the legume Lupinus albus var. multolupa, raw or after alpha-galactoside extraction, and its effect on the bioavailability of protein, P, Ca, and Mg by growing rats was evaluated using a balance technique. The protein and dietary fibre content of the lupin flours studied was high, and 89-94% of the dietary fibre was present as insoluble dietary fibre. The alpha-galactoside extraction process did not disrupt the nutritional quality of protein, and the digestive and metabolic utilisation of this nutrient was high and comparable with that obtained from a casein-cystine control diet (pair-fed to the average daily food intake of the experimental groups fed the different lupin diets). Bioavailability of P, Ca, and Mg from the lupin diets tested was high, and supplementation of an exogenous microbial phytase (750 phytase units/kg) did not cause any further improvement. Mineral content in the bone tissue (femur and sternum) did not correlate to mineral balance, which, on the other hand, was related to the mineral content of other tissues such as blood, plasma, liver and kidney. Due to its ability to grow under adverse edaphic and climatic conditions and to its good nutritional quality, alpha-galactoside-free lupin flour supplemented with the required amounts of minerals and vitamins to meet nutrient requirements can be used as an excellent dietary source for the preparation of dietetic products.

PMID: 16768832 [PubMed - indexed for MEDLINE]

Influence of supplemental magnesium, tryptophan, vitamin C, vitamin E, and herbs on stress responses and pork quality.

J Anim Sci. 2006 Jul;84(7):1827-38

Authors: Peeters E, Driessen B, Geers R

This study investigated the effects of supplemental Mg, Trp, vitamin C, vitamin E, and herbs on stress responses, skin lesions, and meat quality of slaughter pigs (106.0 +/- 8.6 kg of BW). These 5 supplements were tested in 4 similar experiments. In Exp. 1, 2 treatments were tested: 1) control treatment without supplementation, and 2) supplementation of an herbal product (2.5 g/L of drinking water for 2 d). Eighty-eight pigs per treatment were involved, of which 40 were selected for meat quality measurements (over 4 replicates). The experimental design of Exp. 2 and 3 was the same as Exp. 1, except that in Exp. 2 Mg (3 g/L of drinking water for 2 d) was supplemented and in Exp. 3 Trp (6 g/kg of feed, as-fed basis) was supplemented. In Exp. 4, 3 treatments were tested: 1) control treatment without supplementation, 2) supplementation of vitamin C (300 mg/kg of feed for 21 d, as-fed basis), and 3) supplementation of vitamin E (150 mg/kg of feed for 21 d, as-fed basis). In Exp. 4, 66 pigs per treatment were used, of which 42 were evaluated for meat quality (over 6 replicates). Pigs supplemented with vitamin E ate less than control (P = 0.03) or vitamin C-supplemented pigs (P = 0.03). Pigs were transported to a commercial slaughterhouse and were slaughtered after a lairage period. Blood sampling at slaughter revealed no differences between the control and supplemented pigs in plasma cortisol, glucose, lactate, or creatine kinase concentrations. Pigs provided with Mg (P = 0.002) or Trp (P = 0.04) had lower plasma NEFA concentrations than control pigs, and pigs supplemented with vitamin C had greater concentrations than the control (P = 0.03) or vitamin E-supplemented pigs (P = 0.01). Supplementation of the herbal product increased the frequency of pigs with shoulder (P = 0.05) and loin lesions (P = 0.03), whereas Mg lowered the incidence of loin lesions (P = 0.01). Measurements of pH and temperature in the LM and biceps femoris 45 min postmortem revealed no differences among treatments, and no influence of treatments on LM pH, electrical conductivity, and water holding capacity was observed 48 h postmortem. Compared with the control loins, loins of pigs supplemented with vitamin C (Japanese color scale, L*, and a* value; P < 0.05) or vitamin E (Japanese color scale and a* value; P < 0.03) were redder and less pale, and the loin of vitamin E-supplemented pigs was more yellow (b* value; P = 0.04). Generally, Mg could lower loin damage, whereas vitamin C and vitamin E supplementation resulted in a color improvement of the loin.

PMID: 16775067 [PubMed - in process]

Molecular dynamics simulations show that bound Mg2+ contributes to amino acid and aminoacyl adenylate binding specificity in aspartyl-tRNA synthetase through long-range electrostatic interactions.

J Biol Chem. 2006 Jun 14;

Authors: Thompson D, Simonson T

Molecular recognition between the aminoacyl-tRNA synthetase enzymes and their cognate amino acid ligands is essential for the faithful translation of the genetic code. In aspartyl-tRNA synthetase (AspRS), the co-substrate ATP binds preferentially with three associated Mg(2+) cations, in an unusual, bent geometry. The Mg(2+) cations play a structural role and are thought to also participate catalytically in the enzyme reaction. Co-binding of the ATP:Mg(2+)(3) complex was shown recently to increase the Asp/Asn binding free energy difference, indicating that amino acid discrimination is substrate-assisted. Here, we use molecular dynamics free energy simulations and continuum electrostatic calculations to resolve three related questions. First, we show that if one of the Mg(2+) cations is removed, the Asp/Asn binding specificity is strongly reduced. Second, we compute the relative stabilities of the three-cation complex and the two-cation complexes. We find that the three-cation complex is overwhelmingly favoured at ordinary magnesium concentrations, so that the protein is protected against the two-cation state. In the homologous LysRS, the three-cation complex is also strongly favoured, but the third cation does not affect Lys binding. Finally, in tRNA-bound AspRS, the single remaining Mg(2+) cation strongly favours the Asp-adenylate substrate, relative to Asn-adenylate. Thus, in addition to their structural and catalytic roles, the Mg(2+) cations contribute to specificity in AspRS, through long-range electrostatic interactions with the Asp sidechain in both the pre- and post-adenylation states.

PMID: 16774919 [PubMed - as supplied by publisher]

Reactive uptake of nitric acid onto sodium chloride aerosols across a wide range of relative humidities.

J Phys Chem A Mol Spectrosc Kinet Environ Gen Theory. 2006 Jun 22;110(24):7614-20

Authors: Saul TD, Tolocka MP, Johnston MV

Reactive uptake coefficients for nitric acid onto size-selected (d(ve) = 102 and 233 nm) sodium chloride aerosols are determined for relative humidities (RH) between 85% and 10%. Both pure sodium chloride and sodium chloride mixed with magnesium chloride (X(Mg/Na) = 0.114, typical of sea salt) are studied. The aerosol is equilibrated with a carrier gas stream at the desired RH and then mixed with nitric acid vapor at a concentration of 60 ppb in a laminar flow tube reactor. At the end of the reactor, the particle composition is determined in real time with a laser ablation single particle mass spectrometer. For relative humidities above the efflorescence relative humidity (ERH), the particles exist as liquid droplets and the uptake coefficient ranges from 0.05 at 85% RH to >0.1 near the ERH. The droplet sizes, relative humidity and composition dependencies, are readily predicted by thermodynamics. For relative humidities below the ERH, the particles are nominally "solid" and uptake depends on the amount of surface adsorbed water (SAW). The addition of magnesium chloride to the particle phase (0.114 mole ratio of magnesium to sodium) facilitates uptake by increasing the amount of SAW. In the presence of magnesium chloride, the uptake coefficient remains high (>0.1) down to 10% RH, suggesting that the displacement of chloride by nitrate in fine sea salt particles is efficient over the entire range of conditions in the ambient marine environment. In the marine boundary layer, displacement of chloride by nitrate in fine sea salt particles should be nearly complete within a few hours (faster in polluted areas)-a time scale much shorter than the particle residence time in the atmosphere.

PMID: 16774205 [PubMed - in process]

Characterization of a new virulent phage (MLC-A) of Lactobacillus paracasei.

J Dairy Sci. 2006 Jul;89(7):2414-23

Authors: Capra ML, Del L Quiberoni A, Ackermann HW, Moineau S, Reinheimer JA

A new virulent bacteriophage (MLC-A) was recently isolated in Argentina from a probiotic dairy product containing a strain of Lactobacillus paracasei. Observation of the lysate with an electron microscope revealed bacteriophage particles with an icosahedral capsid of 57 +/- 2 nm; with a collar and a noncontractile tail of 156 +/- 3 nm terminating with a baseplate to which a tail fiber was attached. Therefore, phage MLC-A belongs to the Siphoviridae family. This phage was able to survive the pasteurization process and was resistant to alcohols and sodium hypochlorite (400 mg/kg). Only peracetic acid could inactivate high-titer suspensions of phages in a short time. The maximum rates of phage adsorption to its host cells were obtained at 30 degrees C with a pH between 5 and 7, and in the presence of calcium or magnesium ions. The host range of phage MLC-A encompassed L. paracasei and Lactobacillus casei strains, but it was not able to infect Lactobacillus rhamnosus or Lactobacillus gasseri strains. One-step growth kinetics of its lytic development revealed latent and burst periods of 30 and 135 min, respectively, with a burst size of about 69 +/- 4 plaque-forming units per infected cell. Phage MLC-A had a distinctive restriction profile when compared with the 2 well-studied Lactobacillus phages, PL-1 and J-1. The genome size of the MLC-A phage was estimated to be approximately 37 kb. This study presents the description of the first phage specific for L. paracasei isolated in Argentina. The isolation of phage MLC-A indicates that, beside lactic acid bacteria starters, probiotic cultures can also be sensitive to virulent phages in industrial processes.

PMID: 16772557 [PubMed - in process]

The use of selected nutrition supplements and complementary and alternative medicine in liver disease.

Nutr Clin Pract. 2006 Jun;21(3):255-72

Authors: Hanje AJ, Fortune B, Song M, Hill D, McClain C

Almost all patients with liver disease, especially advanced liver disease, have some evidence of malnutrition, including mineral/vitamin deficiency. A major health trend in the United States has been the significant growth in the use of complementary and alternative medicine (CAM), including nutrition supplements and herbal agents. In the 1990s, the United States government created the National Center for Complementary and Alternative Medicine (NCCAM), as well as the Office on Dietary Supplements, to extend our knowledge in these areas. CAM users are often highly educated and frequently use CAM therapy for chronic diseases, including chronic liver disease. Indeed, most studies suggest that patients with chronic liver disease frequently use nutrition supplements and CAM agents in addition to their traditional medicines. The purpose of this review is to provide an update on the role of nutrition supplements and herbals in liver disease. This article will focus mainly on 7 selected agents (vitamin E, zinc, magnesium, S-adenosylmethionine, betaine, silymarin, and glycyrrhizin), for which there have been not only in vitro and animal studies but also human clinical trials, and we will review both potential efficacy and safety issues.

PMID: 16772543 [PubMed - in process]

Catalytic mechanism of transition-metal compounds on Mg hydrogen sorption reaction.

J Phys Chem B Condens Matter Mater Surf Interfaces Biophys. 2006 Jun 8;110(22):11020-4

Authors: Barkhordarian G, Klassen T, Bormann R

The catalytic mechanisms of transition-metal compounds during the hydrogen sorption reaction of magnesium-based hydrides were investigated through relevant experiments. Catalytic activity was found to be influenced by four distinct physico-thermodynamic properties of the transition-metal compound: a high number of structural defects, a low stability of the compound, which however has to be high enough to avoid complete reduction of the transition metal under operating conditions, a high valence state of the transition-metal ion within the compound, and a high affinity of the transition-metal ion to hydrogen. On the basis of these results, further optimization of the selection of catalysts for improving sorption properties of magnesium-based hydrides is possible. In addition, utilization of transition-metal compounds as catalysts for other hydrogen storage materials is considered.

PMID: 16771356 [PubMed - in process]

Nonpharmacologic strategies for managing hypertension.

Am Fam Physician. 2006 Jun 1;73(11):1953-6

Authors: Wexler R, Aukerman G

The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure recommends lifestyle modification for all patients with hypertension or prehypertension. Modifications include reducing dietary sodium to less than 2.4 g per day; increasing exercise to at least 30 minutes per day, four days per week; limiting alcohol consumption to two drinks or less per day for men and one drink or less per day for women; following the Dietary Approaches to Stop Hypertension eating plan (high in fruits, vegetables, potassium, calcium, and magnesium; low in fat and salt); and achieving a weight loss goal of 10 lb (4.5 kg) or more. Alternative treatments such as vitamin C, coenzyme Q10, magnesium, and omega-3 fatty acids have been suggested for managing hypertension, but evidence for their effectiveness is lacking.

PMID: 16770925 [PubMed - indexed for MEDLINE]

Unusual asymptomatic giant sialolith of the submandibular gland: a clinical report.

J Craniofac Surg. 2006 May;17(3):549-52

Authors: Graziani F, Vano M, Cei S, Tartaro G, Mario G

This report presents an unusual case of asymptomatic sialolith of the submandibular gland. A 61-year-old man was referred to our department for multiple extractions. An ortopantomographic exam revealed the existence of a large radiopacity in the right premolar mandibular region. The patient was completely asymptomatic and no episodes of pain and swelling had occurred in the previous years. Ultrasonography and clinical examination confirmed the diagnosis of sialolithiasis of the submandibular duct. The calculus was removed trans-orally in local anaesthesia. The sialolith measured 22 mm and it was mainly constituted by phosphate, calcium and smaller amounts of magnesium. The bacteriological exam revealed the presence of Streptococcus Mitis, Streptococcus Salivarius and non-pathogenic Neisserie. Postoperative course was uneventful. Even a sialolith of significant dimensions may not be symptomatic. Nevertheless, the likelihood of future complications may constitute an indication for surgical removal of abnormal asymptomatic sialoliths.

PMID: 16770196 [PubMed - in process]