Showing papers on "Low protein published in 2010"

Diets with High or Low Protein Content and Glycemic Index for Weight-Loss Maintenance

Abstract: Background Studies of weight-control diets that are high in protein or low in glycemic index have reached varied conclusions, probably owing to the fact that the studies had insufficient power. Methods We enrolled overweight adults from eight European countries who had lost at least 8% of their initial body weight with a 3.3-MJ (800-kcal) low-calorie diet. Participants were randomly assigned, in a two-by-two factorial design, to one of five ad libitum diets to prevent weight regain over a 26-week period: a low-protein and low-glycemic-index diet, a low-protein and high-glycemic-index diet, a high-protein and low-glycemic-index diet, a high-protein and high-glycemic-index diet, or a control diet. Results A total of 1209 adults were screened (mean age, 41 years; body-mass index [the weight in kilograms divided by the square of the height in meters], 34), of whom 938 entered the low-calorie-diet phase of the study. A total of 773 participants who completed that phase were randomly assigned to one of the five...

Genome-wide association study identifies variants in the MHC class I, IL10, and IL23R-IL12RB2 regions associated with Behcet's disease

Abstract: Behcet's disease is a genetically complex disease of unknown etiology characterized by recurrent inflammatory attacks affecting the orogenital mucosa, eyes and skin. We performed a genome-wide association study with 311,459 SNPs in 1,215 individuals with Behcet's disease (cases) and 1,278 healthy controls from Turkey. We confirmed the known association of Behcet's disease with HLA-B*51 and identified a second, independent association within the MHC Class I region. We also identified an association at IL10 (rs1518111, P = 1.88 x 10(-8)). Using a meta-analysis with an additional five cohorts from Turkey, the Middle East, Europe and Asia, comprising a total of 2,430 cases and 2,660 controls, we identified associations at IL10 (rs1518111, P = 3.54 x 10(-18), odds ratio = 1.45, 95% CI 1.34-1.58) and the IL23R-IL12RB2 locus (rs924080, P = 6.69 x 10(-9), OR = 1.28, 95% CI 1.18-1.39). The disease-associated IL10 variant (the rs1518111 A allele) was associated with diminished mRNA expression and low protein production.

Treatment of Bacterial Prostatitis

Abstract: Prostatitis is characterized by voiding symptoms and genitourinary pain and is sometimes associated with sexual dysfunction. Up to 25% of men receive a diagnosis of prostatitis in their lifetime, but <10% have a proven bacterial infection. The causes and treatment of nonbacterial prostatitis are largely unknown, but bacterial prostatitis is caused by infection with uropathogens, especially gram-negative bacilli, although infection is sometimes due to gram-positive and atypical microorganisms. Acute bacterial prostatitis is easily diagnosed (by abrupt urogential and often systemic symptoms, along with bacteriuria) and treated (by systemic antibiotic therapy). Chronic bacterial prostatitis is characterized by prolonged or recurrent symptoms and relapsing bacteriuria; diagnosis traditionally requires comparing urinary specimens obtained before with specimens obtained after prostatic massage. Treating chronic bacterial prostatitis requires prolonged therapy with an antibiotic that penetrates the prostate (ie, one with high lipid solubility, a low degree of ionization, high dissociation constant, low protein binding, and small molecular size). We review recent pharmacological and clinical data on treating bacterial prostatitis.

The Diet, Obesity and Genes (Diogenes) Dietary Study in eight European countries – a comprehensive design for long-term intervention

Abstract: Diogenes is a Pan-European, randomized, controlled dietary intervention study investigating the effects of dietary protein and glycaemic index on weight (re)gain, metabolic and cardiovascular risk factors in obese and overweight families in eight European centres. The article is methodological in character, and the presentation of 'results' will be limited to baseline characteristics of the study populations included. A total of 891 families with at least one overweight/obese parent underwent screening. The parents started an initial 8-week low-calorie diet and families with minimum one parent attaining a weight loss of > or = 8%, were randomized to one of five energy ad libitum, low-fat (25-30 E%) diets for 6 or 12 months: low protein/low glycaemic index, low protein/high glycaemic index, high protein/low glycaemic index, high protein/high glycaemic index or control (national dietary guidelines). At two centres the families were provided dietary instruction plus free foods for 6 months followed by 6-month dietary instruction only. At the remaining six centres the families received dietary instruction only for 6 months. The median weight loss during the low-calorie diet was 10.3 kg (inter-quartile range: 8.7-12.8 kg, n = 775). A total of 773 adults and 784 children were randomized to the 6-month weight (re)gain prevention phase. Despite major cultural and dietary regional differences in Europe, interventions addressing effects of dietary factors are feasible with a reasonable attrition.

Microfiltration isolation of human urinary exosomes for characterization by MS.

Abstract: PURPOSE: The purpose of this study was to address the hypothesis that small vesicular urinary particles known as exosomes could be selectively microfiltered using low protein-binding size exclusion filters, thereby simplifying their use in clinical biomarker discovery studies. EXPERIMENTAL DESIGN: We characterized a microfiltration approach using a low protein binding, hydrophilized polyvinylidene difluoride membrane to easily and efficiently isolate urinary exosomes from fresh, room temperature or 4 degrees C urine, with a simultaneous depletion of abundant urinary proteins. Using LC-MS, immunoblot analysis, and electron microscopy methods, we demonstrate this method to isolate intact exosomes and thereby enrich for a low abundant urinary proteome. RESULTS: In comparison to other standard methods of exosome isolation including ultracentrifugation and nanofiltration, we demonstrate equivalent enrichment of the exosome proteome with reduced co-purification of abundant urinary proteins. CONCLUSION AND CLINICAL RELEVANCE: In conclusion, we demonstrate a microfiltration isolation method that preserves the exosome structure, reduces contamination from higher abundant urinary proteins, and can be easily implemented into mass spectrometry analysis for biomarker discovery efforts or incorporation into routine clinical laboratory applications to yield higher sample throughput.

High-Yield Expression of Heterologous [FeFe] Hydrogenases in Escherichia coli

Abstract: Background The realization of hydrogenase-based technologies for renewable H2 production is presently limited by the need for scalable and high-yielding methods to supply active hydrogenases and their required maturases. Principal Findings In this report, we describe an improved Escherichia coli-based expression system capable of producing 8–30 mg of purified, active [FeFe] hydrogenase per liter of culture, volumetric yields at least 10-fold greater than previously reported. Specifically, we overcame two problems associated with other in vivo production methods: low protein yields and ineffective hydrogenase maturation. The addition of glucose to the growth medium enhances anaerobic metabolism and growth during hydrogenase expression, which substantially increases total yields. Also, we combine iron and cysteine supplementation with the use of an E. coli strain upregulated for iron-sulfur cluster protein accumulation. These measures dramatically improve in vivo hydrogenase activation. Two hydrogenases, HydA1 from Chlamydomonas reinhardtii and HydA (CpI) from Clostridium pasteurianum, were produced with this improved system and subsequently purified. Biophysical characterization and FTIR spectroscopic analysis of these enzymes indicate that they harbor the H-cluster and catalyze H2 evolution with rates comparable to those of enzymes isolated from their respective native organisms. Significance The production system we describe will facilitate basic hydrogenase investigations as well as the development of new technologies that utilize these prolific H2-producing enzymes. These methods can also be extended for producing and studying a variety of oxygen-sensitive iron-sulfur proteins as well as other proteins requiring anoxic environments.

Fragment screening by surface plasmon resonance.

Abstract: Fragment-based drug discovery is a validated approach for the discovery of drug candidates. However, the weak affinity of fragment compounds requires highly sensitive biophysical techniques, such as nuclear magnetic resonance (NMR) or X-ray crystallography, to identify hits. Thus the advantages of screening small fragment libraries are partly offset by the high cost of biophysical analyses. Here we present a method for biosensor-based fragment screening using surface plasmon resonance (SPR). In order to reduce the false positive detection rate we present a novel method of data analysis that incorporates multiple referencing with ligand efficiency. By implementing all necessary steps for assay design, data analysis and interpretation, SPR-based fragment screening has potential to eliminate all nonspecific (false positive) binders. Therefore, given the advantages of low protein consumption, rapid assay development and kinetic and thermodynamic validation of hits, SPR can be considered as a primary screening technology for fragment-based drug discovery.

Optimization of human milk fortification for preterm infants: new concepts and recommendations

Abstract: Preterm infants fed fortified human milk (HM) in standard (STD) fashion grow slower than preterm formula fed infants. Recently, low protein intake has been proven to be the primary limiting factor responsible for this growth failure. The main reason of protein undernutrition despite fortification is that STD fortification is based on the customary assumptions about the composition of HM. However, the protein concentration of preterm HM is variable and decreases with the duration of lactation. Also, the protein concentration of banked donor milk, which is most often provided by mothers of term infants, is likely to be lower. Hence, most of the HM fed to preterm infants during the fortification period is likely to have an inadequately low protein concentration. This hypothesis has been confirmed very recently by comparing the assumed and actual protein intakes in preterm infants fed fortified HM. Novel fortification models have been devised to deal with the problem of ongoing protein undernutrition. Individualized fortification is the recommended method to optimize HM fortification. There are two models of individualization: ‘‘adjustable fortification’’ and ‘‘targeted fortification’’. Both ways are feasible and effective in improving protein intakes and growth. Adjustable fortification has the advantage of being practical and avoids excessive protein intakes.

Molecular Causes for BUBR1 Dysfunction in the Human Cancer Predisposition Syndrome Mosaic Variegated Aneuploidy

Abstract: Genetic mutations in the mitotic regulatory kinase BUBR1 are associated with the cancer-susceptible disorder mosaic variegated aneuploidy (MVA). In patients with biallelic mutations, a missense mutation pairs with a truncating mutation. Here, we show that cell lines derived from MVA patients with biallelic mutations have an impaired mitotic checkpoint, chromosome alignment defects, and low overall BUBR1 abundance. Ectopic expression of BUBR1 restored mitotic checkpoint activity, proving that BUBR1 dysfunction causes chromosome segregation errors in the patients. Combined analysis of patient cells and functional protein replacement shows that all MVA mutations fall in two distinct classes: those that impose specific defects in checkpoint activity or microtubule attachment and those that lower BUBR1 protein abundance. Low protein abundance is the direct result of the absence of transcripts from truncating mutants combined with high protein turnover of missense mutants. In this group of missense mutants, the amino acid change consistently occurs in or near the BUBR1 kinase domain. Our findings provide a molecular explanation for chromosomal instability in patients with biallelic genetic mutations in BUBR1.

Leucine Supplementation of a Low-Protein Meal Increases Skeletal Muscle and Visceral Tissue Protein Synthesis in Neonatal Pigs by Stimulating mTOR-Dependent Translation Initiation

Abstract: Protein synthesis and eukaryotic initiation factor (eIF) activation are increased in skeletal muscle of neonatal pigs parenterally infused with amino acids. Leucine appears to be the most effective single amino acid to trigger these effects. To examine the response to enteral leucine supplementation, overnight food-deprived 5-d-old pigs were gavage fed at 0 and 60 min a: 1) low-protein diet (LP); 2) LP supplemented with leucine (LP+L) to equal leucine in the high-protein diet (HP); or 3) HP diet. Diets were isocaloric and equal in lactose. Fractional protein synthesis rates and translation initiation control mechanisms were examined in skeletal muscles and visceral tissues 90 min after feeding. Protein synthesis rates in longissimus dorsi, gastrocnemius, and masseter muscles, heart, jejunum, kidney, and pancreas, but not liver, were greater in the LP+L group compared with the LP group and did not differ from the HP group. Feeding LP+L and HP diets compared with the LP diet increased phosphorylation of mammalian target of rapamycin (mTOR), 4E-binding protein 1, ribosomal protein S6 kinase-1, and eIF4G and formation of the active eIF4E·eIF4G complex in longissimus dorsi muscle. In all tissues except liver, activation of mTOR effectors increased in pigs fed LP+L and HP vs. LP diets. Our results suggest that leucine supplementation of a low-protein meal stimulates protein synthesis in muscle and most visceral tissues to a rate similar to that achieved by feeding a high-protein meal and this stimulation involves activation of mTOR downstream effectors.

Consuming cassava as a staple food places children 2-5 years old at risk for inadequate protein intake, an observational study in Kenya and Nigeria

Abstract: Background: Inadequate protein intake is known to be deleterious in animals. Using WHO consensus documents for human nutrient requirements, the protein:energy ratio (P:E) of an adequate diet is > 5%. Cassava has a very low protein content. This study tested the hypothesis that Nigerian and Kenyan children consuming cassava as their staple food are at greater risk for inadequate dietary protein intake than those children who consume less cassava. Methods: A 24 hour dietary recall was used to determine the food and nutrient intake of 656 Nigerian and 449 Kenyan children aged 2-5 years residing in areas where cassava is a staple food. Anthropometric measurements were conducted. Diets were scored for diversity using a 12 point score. Pearson’s Correlation Coefficients were calculated to relate the fraction of dietary energy obtained from cassava with protein intake, P:E, and dietary diversity. Results: The fraction of dietary energy obtained from cassava was > 25% in 35% of Nigerian children and 89% of Kenyan children. The mean dietary diversity score was 4.0 in Nigerian children and 4.5 in Kenyan children, although the mean number of different foods consumed on the survey day in Nigeria was greater than Kenya, 7.0 compared to 4.6. 13% of Nigerian and 53% of Kenyan children surveyed had inadequate protein intake. The fraction of dietary energy derived from cassava was negatively correlated with protein intake, P:E, and dietary diversity. Height-for age z score was directly associated with protein intake and negatively associated with cassava consumption using regression modeling that controlled for energy and zinc intake. Conclusions: Inadequate protein intake was found in the diets of Nigerian and Kenyan children consuming cassava as a staple food. Inadequate dietary protein intake is associated with stunting in this population. Interventions to increase protein intake in this vulnerable population should be the focus of future work.

How amelogenin orchestrates the organization of hierarchical elongated microstructures of apatite.

Abstract: Amelogenin (Amel) accelerates the nucleation of hydroxyapatite (HAP) in supersaturated solutions of calcium phosphate (Ca−P), shortening the induction time (delay period), under near-physiological conditions of pH, temperature, and ionic strength. Hierarchically organized Amel and amorphous calcium phosphate (ACP) nanorod microstructures are formed involving a coassembly of Amel−ACP particles at low supersaturations and low protein concentrations in a slow, well-controlled, constant composition (CC) crystallization system. At the earliest nucleation stages, the CC method allows the capture of prenucleation clusters and intermediate nanoclusers, spherical nanoparticles, and nanochains prior to enamel-like nanorod microstructure formations at later maturation stages. Amel−ACP nanoscaled building blocks are formed spontaneously by synergistic interactions between flexible Amel protein molecules and Ca−P prenucleation clusters, and these spherical nanoparticles evolve by orientated aggregation to form nanocha...

Leucine Supplementation of a Low-Protein Meal Increases Skeletal Muscle and Visceral Tissue Protein Synthesis in Neonatal Pigs by Stimulating mTOR-Dependent

Abstract: Protein synthesis and eukaryotic initiation factor (eIF) activation are increased in skeletal muscle of neonatal pigs parenterally infused with amino acids. Leucine appears to be the most effective single amino acid to trigger these effects. To examine the response to enteral leucine supplementation, overnight food-deprived 5-d-old pigs were gavage fed at 0 and 60 min a: 1) low-protein diet (LP);2) LP supplemented with leucine (LP+L) to equal leucine in the high-protein diet (HP); or 3) HP diet. Diets were isocaloric and equal in lactose. Fractional protein synthesis rates and translation initiation control mechanisms were examined in skeletal muscles and visceral tissues 90 min after feeding. Protein synthesis rates in longissimus dorsi, gastrocnemius, and masseter muscles, heart, jejunum, kidney, and pancreas, but not liver, were greater in the LP+L group compared with the LP group and did not differ from the HP group. Feeding LP+L and HP diets compared with the LP diet increased phosphorylation of mammalian target of rapamycin (mTOR), 4E-binding protein 1, ribosomal protein S6 kinase-1, and eIF4G and formation of the active eIF4E×eIF4G complex in longissimus dorsi muscle. In all tissues except liver, activation of mTOR effectors increased in pigs fed LP+L and HP vs. LP diets. Our results suggest that leucine supplementation of a low-protein meal stimulates protein synthesis in muscle and most visceral tissues to a rate similar to that achieved by feeding a high-protein meal and this stimulation involves activation of mTOR downstream effectors. J. Nutr. 140: 2145–2152, 2010.

A virosomal formulated Her-2/neu multi-peptide vaccine induces Her-2/neu-specific immune responses in patients with metastatic breast cancer: a phase I study

Abstract: We have previously shown in mice that vaccination with three Her-2-peptides representing B-cell epitopes of the extracellular domain of Her-2/neu induces Her-2/neu-specific IgG antibodies with strong anti-tumor activity in vitro and in vivo. We have now finalized a phase I clinical trial with an anti-Her-2/neu vaccine-construct of immunopotentiating reconstituted influenza virosomes with the three peptides in patients with metastatic breast cancer (MBC). Ten MBC patients with low protein overexpression of Her-2/neu of MBC (+ or ++ upon immunohistochemistry, FISH negative) and positive hormone receptor status were enrolled in a single center phase I study. The virosomal formulated vaccine, consisting of 10 μg/peptide, was intramuscularly applied three times on days 1, 28, and 56. The primary endpoint of the study, which lasted 12 weeks, was safety, the secondary endpoint immunogenicity. Local erythema at the injection site was the only vaccine-related side effect occurring in four patients. In 8 of 10 patients an increase in peptide-specific antibody titer measured by ELISA was found. Importantly, the induced antibodies were also directed against the native Her-2/neu protein. Cellular immune responses, as measured by in vitro production of IL-2, IFN-γ, and TNF-α of PBMCs showed a marked increase after vaccination in the majority of vaccinees. Notably, the number of CD4+CD25+Foxp3+T regulatory cells, which were significantly increased compared to healthy controls prior to vaccination, was markedly reduced following vaccination. In all, the immunological responses after vaccination indicated that the patients in stage IV of disease were immunocompetent and susceptible to vaccination. The Her-2/neu multipeptide vaccine was safe, well tolerated and effective in overcoming immunological tolerance to Her-2/neu. The induction of anti-Her-2-specific antibodies could result in clinical benefit comparable to passive anti-Her-2 antibody therapy.

The Effect of Protein and Glycemic Index on Children's Body Composition: The DiOGenes Randomized Study

Abstract: OBJECTIVE: To investigate the effect of protein and glycemic index (GI) on body composition among European children in the randomized, 6-month dietary intervention DiOGenes (diet, obesity, and genes) family-based study. PATIENTS AND METHODS: In the study, 827 children (381 boys and 446 girls), aged 5 to 18 years, completed baseline examinations. Families with parents who lost ≥8% of their weight during an 8-week run-in low-calorie diet period were randomly assigned to 1 of 5 ad libitum diets: low protein (LP)/low glycemic index (LGI); LP/high GI (HGI); high protein (HP)/LGI; HP/HGI; and control diet. The target difference was 15 GI U between the LGI/HGI groups and 13 protein percentage points between the LP/HP groups. There were 658 children examined after 4 weeks. Advice on food-choice modification was provided at 6 visits during this period. No advice on weight loss was provided because the focus of the study was the ability of the diets to affect outcomes through appetite regulation. Anthropometric measurements and body composition were assessed at baseline, week 4, and week 26. RESULTS: In the study, 465 children (58.1%) completed all assessments. The achieved differences between the GI and protein groups were 2.3 GI U and 4.9 protein percentage points, respectively. The LP/HGI group increased body fat percentage significantly more than the other groups (P = .040; partial η2 = 0.039), and the percentage of overweight/obese children in the HP/LGI group decreased significantly during the intervention (P = .031). CONCLUSIONS: Neither GI nor protein had an isolated effect on body composition. However, the LP/HGI combination increased body fat, whereas the HP/LGI combination was protective against obesity in this sample of children.

Low-protein and protein-redistribution diets for Parkinson's disease patients with motor fluctuations: A systematic review†‡

Abstract: The American Academy of Neurology suggests advising the redistribution of daily protein meal content to every Parkinson's disease (PD) patient with motor fluctuations during levodopa treatment. However, no comprehensive evaluation of this complementary therapy has been performed. A systematic review of intervention studies investigating the neurologic outcome of low-protein (<0.8 g/kg of ideal weight/day) and protein-redistribution diets in patients with PD experiencing motor fluctuations during levodopa treatment. All studies (uncontrolled or randomized) investigating a low-protein and/or a protein-redistribution diet (LPD and PRD) and involving patients with PD with motor fluctuations were included, provided that sufficient information on dietary protein content and neurologic outcome measures was available. We identified 16 eligible studies, but they were markedly heterogeneous. There was not enough evidence to support the use of LPD. Response to PRD seemed very good. Acceptability appeared high upon introduction, but it seemed to progressively decrease over time. On average, PRD resulted in improved motor function, but also complications occurred. At the beginning, drop-outs were due to levodopa side effects rather than unsatisfactory benefits. Long-term adherence was more affected by changes in dietary habits than by diet-related side effects. Efficacy and benefits appeared to be higher when the intervention was proposed to subjects in the early stages of PD. PRD can be safely advised to fluctuating patients with PD, but those in whom benefits override the possible inconveniences still need to be identified. The long-term effects of PRD on nutritional status should be evaluated and true effectiveness in clinical practice should be reassessed, given the changes in levodopa formulations and the introduction of several adjuvants (levodopa degradation inhibitors and/or dopamine agonists).

Comparative transcriptional profiling of the limbal epithelial crypt demonstrates its putative stem cell niche characteristics

Abstract: The Limbal epithelial crypt (LEC) is a solid cord of cells, approximately 120 microns long. It arises from the undersurface of interpalisade rete ridges of the limbal palisades of Vogt and extends deeper into the limbal stroma parallel or perpendicular to the palisade. There are up to 6 or 7 such LEC, variably distributed along the limbus in each human eye. Morphological and immunohistochemical studies on the limbal epithelial crypt (LEC) have demonstrated the presence of limbal stem cells in this region. The purpose of this microarray study was to characterise the transcriptional profile of the LEC and compare with other ocular surface epithelial regions to support our hypothesis that LEC preferentially harbours stem cells (SC). LEC was found to be enriched for SC related Gene Ontology (GO) terms including those identified in quiescent adult SC, however similar to cornea, limbus had significant GO terms related to proliferating SC, transient amplifying cells (TAC) and differentiated cells (DC). LEC and limbus were metabolically dormant with low protein synthesis and downregulated cell cycling. Cornea had upregulated genes for cell cycling and self renewal such as FZD7, BTG1, CCNG, and STAT3 which were identified from other SC populations. Upregulated gene expression for growth factors, cytokines, WNT, Notch, TGF-Beta pathways involved in cell proliferation and differentiation were noted in cornea. LEC had highest number of expressed sequence tags (ESTs), downregulated and unknown genes, compared to other regions. Genes expressed in LEC such as CDH1, SERPINF1, LEF1, FRZB1, KRT19, SOD2, EGR1 are known to be involved in SC maintenance. Genes of interest, in LEC belonging to the category of cell adhesion molecules, WNT and Notch signalling pathway were validated with real-time PCR and immunofluorescence. Our transcriptional profiling study identifies the LEC as a preferential site for limbal SC with some characteristics suggesting that it could function as a 'SC niche' supporting quiescent SC. It also strengthens the evidence for the presence of "transient cells" in the corneal epithelium. These cells are immediate progeny of SC with self-renewal capacity and could be responsible for maintaining epithelial turn over in normal healthy conditions of the ocular surface (OS). The limbus has mixed population of differentiated and undifferentiated cells.

Roles of water and solids composition in the control of glass transition and stickiness of milk powders.

Abstract: Plasticization and glass transition of amorphous components in food powders often result in stickiness and caking. The glass transition temperature (T(g)) of milk powders was measured by differential scanning calorimetry (DSC) and a viscometer method was used to determine sticky-point temperatures. Water sorption isotherms were established for varying solids compositions. Lactose contents were analyzed by high-performance anion exchange chromatography with pulsed amperometric detection (HPAE-PAD) and proteins were identified using SDS-PAGE gel electrophoresis. Solids composition and water affected both the T(g) and stickiness behavior. Stickiness was governed by carbohydrates and water plasticization. At low protein contents, precrystallization of lactose decreased the sticky point temperature, but increasing protein content in all milk powders decreased stickiness at all water activities. The results showed that glass transition can be used to describe time-dependent stickiness and crystallization phenomena, and it can be used as a parameter to control and reduce stickiness of dairy solids with various compositions.

DMSO-Induced Denaturation of Hen Egg White Lysozyme

Abstract: We report on the size, shape, structure, and interactions of lysozyme in the ternary system lysozyme/DMSO/water at low protein concentrations. Three structural regimes have been identified, which we term the “folded” (0 0.7. This drastic change in the protein’s size coincides with a loss of the characteristic tertiary structure. It is preceded by a compaction of the local environment of the tryptophan residues and accompanied by a large increase in the protein’s overall flexibility. In terms of secondary structure, there is a gradual loss of α-helix and concomitant increase of β-sheet structural elements toward φDMSO = 0.7, while an increase in φDMSO at even higher DMSO volume fractions reduces the presence of both α-helix and β-sheet secondary...

Impact of dietary protein on lipid metabolism-related gene expression in porcine adipose tissue.

Abstract: High dietary protein can reduce fat deposition in animal subcutaneous adipose tissue, but little is known about the mechanism. Sixty Wujin pigs of about 15 kg weight were fed either high protein (HP: 18%) or low protein (LP: 14%) diets, and slaughtered at body weights of 30, 60 or 100 kg. Bloods were collected to measure serum parameters. Subcutaneous adipose tissues were sampled for determination of adipocyte size, protein content, lipid metabolism-related gene expression, and enzyme activities. HP significantly reduced adipocyte size, fat meat percentage and backfat thickness, but significantly increased daily gain, lean meat percentage and loin eye area at 60 and 100 kg. Serum free fatty acid and triglyceride concentrations in the HP group were significantly higher than in the LP group. Serum glucose and insulin concentrations were not significantly affected by dietary protein at any body weight. HP significantly reduced gene expression of acetyl CoA carboxylase (ACC), fatty acid synthase (FAS) and sterol regulatory element binding protein 1c (SREBP-1c) at 60 kg and 100 kg; however, the mRNA level and enzyme activity of FAS were increased at 30 kg. HP promoted gene and protein expression and enzyme activities of lipoprotein lipase (LPL), carmitine palmtoyltransferase-1B (CPT-1B), peroxisome proliferator-activated receptor γ (PPARγ) and adipocyte-fatty acid binding proteins (A-FABP) at 60 kg, but reduced their expression at 100 kg. Gene expression and enzyme activity of hormone sensitive lipase (HSL) was reduced markedly at 60 kg but increased at 100 kg by the high dietary protein. Levels of mRNA, enzyme activities and protein expression of ACC, FAS, SREBP-1c and PPARγ in both LP and HP groups increased with increasing body weight. However, gene and protein expression levels/enzyme activities of LPL, CPT-1B, A-FABP and HSL in both groups were higher at 60 kg than at 30 and 100 kg. Fat deposition in Wujin pigs fed high dietary protein for 25 weeks was reduced mainly by depression of lipogenic gene expression. The mechanism of lipid transport, lipolysis and oxidation in adipose tissue regulated by dietary protein appeared to be different at 60 kg and 100 kg body weights.

New concepts and objectives for protein-amino acid nutrition in rabbits: a review

Abstract: In the European context, the new legislation to avoid mineral contamination and the ban on antibiotics as growth promoters has led to the definition of new objectives in respect of nitrogen supply. The present study summarizes the state of nitrogen nutrition in rabbits and reviews the role of protein and amino acids in rabbit health and the new nitrogen value of protein sources based on true ileal digestibility (TID) for future recommendations. The main sources of nitrogen for microbial growth are ammonia, urea and protein (endogenous and dietary). The surplus of nitrogen flow to the caecum increases mortality rates during fattening by favouring the growth of potential pathogenic bacteria. Accordingly, feeding strategies to reduce ileal nitrogen flow have been reviewed. A large reduction of dietary protein level might have negative consequences on growth performances and mortality. In order to formulate balanced low protein diets, data on ileal and faecal amino acid digestibility of 14 raw materials is summarized. The use of this different unit for amino acid digestibility is also discussed.

Dietary strategy to manipulate ad libitum macronutrient intake, and glycaemic index, across eight European countries in the Diogenes Study

Abstract: The aim of this study was to describe the development and implementation of a multifaceted, low-fat, weight-loss strategy for a Pan-European randomized controlled dietary intervention study, Diogenes. There were 891 families with at least one overweight/obese parent who underwent screening. Eligible, overweight/obese adults followed an 8-week weight-loss phase with a fixed low-energy diet (800 kcal). On attaining weight loss of > or = 8%, families were randomized to a 6- or 12-month low-fat (25-30%E) diet either based on national dietary guidelines or one of four interventions: low protein (LP)/low glycaemic index (LGI), LP/high GI (HGI), high protein (HP)/LGI and HP/HGI. The impact of each diet in preventing weight (re)gain was tested. A points-based system was used to manipulate dietary protein and carbohydrate. Manipulating carbohydrate composition involved substituting foods with a relatively high or low GI. A questionnaire was designed and completed by study investigators, providing feedback on the dietary intervention methods used to inform future interventions. The points system allowed macronutrient manipulations without compromising dietary flexibility or enforcing energy restrictions. Reported centre/participant differences in the ease of implementing the intervention may reflect dietary diversity and personal preferences for specific weight-management strategies. The points system provides a useful starting point for designing improved experimental paradigms for the manipulation of dietary intake in future trials.

Changes in weight loss, body composition and cardiovascular disease risk after altering macronutrient distributions during a regular exercise program in obese women

Abstract: Background: This study’s purpose investigated the impact of different macronutrient distributions and varying caloric intakes along with regular exercise for metabolic and physiological changes related to weight loss. Methods: One hundred forty-one sedentary, obese women (38.7 ± 8.0 yrs, 163.3 ± 6.9 cm, 93.2 ± 16.5 kg, 35.0 ± 6.2 kgm -2 , 44.8 ± 4.2% fat) were randomized to either no diet + no exercise control group (CON) a no diet + exercise control (ND), or one of four diet + exercise groups (high-energy diet [HED], very low carbohydrate, high protein diet [VLCHP], low carbohydrate, moderate protein diet [LCMP] and high carbohydrate, low protein [HCLP]) in addition to beginning a 3xweek -1 supervised resistance training program. After 0, 1, 10 and 14 weeks, all participants completed testing sessions which included anthropometric, body composition, energy expenditure, fasting blood samples, aerobic and muscular fitness assessments. Data were analyzed using repeated measures ANOVA with an alpha of 0.05 with LSD post-hoc analysis when appropriate. Results: All dieting groups exhibited adequate compliance to their prescribed diet regimen as energy and macronutrient amounts and distributions were close to prescribed amounts. Those groups that followed a diet and exercise program reported significantly greater anthropometric (waist circumference and body mass) and body composition via DXA (fat mass and % fat) changes. Caloric restriction initially reduced energy expenditure, but successfully returned to baseline values after 10 weeks of dieting and exercising. Significant fitness improvements (aerobic capacity and maximal strength) occurred in all exercising groups. No significant changes occurred in lipid panel constituents, but serum insulin and HOMA-IR values decreased in the VLCHP group. Significant reductions in serum leptin occurred in all caloric restriction + exercise groups after 14 weeks, which were unchanged in other non-diet/non-exercise groups. Conclusions: Overall and over the entire test period, all diet groups which restricted their caloric intake and exercised experienced similar responses to each other. Regular exercise and modest caloric restriction successfully promoted anthropometric and body composition improvements along with various markers of muscular fitness. Significant increases in relative energy expenditure and reductions in circulating leptin were found in response to all exercise and diet groups. Macronutrient distribution may impact circulating levels of insulin and overall ability to improve strength levels in obese women who follow regular exercise.