Four weeks supplementation with Lactobacillus paracasei subsp. paracasei L. casei W8® shows modest effect on triacylglycerol in young healthy adults

The microbiota has been shown to have the potential to affect appetite and blood lipids positively in animal studies. We investigated if four weeks supplementation with Lactobacillus paracasei subsp. paracasei L. casei W8® (L. casei W8) had an effect on subjective appetite sensation, ad libitum energy intake, glucagon-like peptide 1 (GLP-1), glucose and insulin response in humans. Secondarily, we explored potential effects on blood lipids, fatty acids and stearoyl-CoA desaturase-1 (SCD1) activity in humans as well as SCD1 expression in piglets given L. casei W8 for two weeks. 64 healthy participants completed the double-blinded, randomised, controlled, parallel four weeks study with supplementation of L. casei W8 (1010 cfu) or placebo capsules. A meal test was conducted before and after the intervention, where subjective appetite, ad libitum energy intake, GLP-1, glucose and insulin response were measured. Additionally fasting blood lipids and fatty acids concentrations were measured. Sixteen piglets were randomised into two groups: L. casei W8 (1010 cfu/day) as top dressing on morning fed or no treatment. After two weeks piglets were sacrificed and tissue from ileum, jejunum and skeletal muscle were sampled for mRNA analyses of SCD1 expression. Compared to placebo, L. casei W8 did not affect appetite, ad libitum energy intake, GLP-1, glucose and insulin response and total, high-density or low-density lipoprotein cholesterol levels after four weeks intervention. Triacylglycerol decreased in the L. casei W8 group compared to placebo at week 4 (P=0.03). The C16:1n-7/C16:0 ratio, reflecting SCD1 activity, tended to decrease when having L. casei W8 (P=0.06) compared to placebo. Muscle SCD1 expression decreased in piglets supplemented with L. casei W8 compared to control. In conclusion, supplementation with L. casei W8 did not affect appetite parameters, glucose or insulin responses; but appear to be able to lower triacylglycerol levels, possibly by reducing its production.

Penetratin-Mediated Transepithelial Insulin Permeation: Importance of Cationic Residues and pH for Complexation and Permeation

Penetratin is a widely used carrier peptide showing promising potential for mucosal delivery of therapeutic proteins. In the present study, the importance of specific penetratin residues and pH was investigated with respect to complexation with insulin and subsequent transepithelial insulin permeation. Besides penetratin, three analogues were studied. The carrier peptide-insulin complexes were characterized in terms of size and morphology at pH 5, 6.5, and 7.4 by dynamic light scattering (DLS) and transmission electron microscopy (TEM), respectively. At pH 7.4 mainly very large complexes were present, while much smaller complexes dominated at pH 5. Presence of arginine residues in the carrier peptide proved to be a prerequisite for complexation with insulin as well as for enhanced transepithelial insulin permeation in vitro. Rearrangement of tryptophan residues resulted in significantly increased insulin permeation as compared to that of the parent penetratin. In general, pre-complexation with penetratin and its analogues at pH 5 gave rise to increased insulin permeation as compared to that observed at pH 7.4; this finding was further supported by a preliminary in vivo study using the parent penetratin.

Conjugation of cell-penetrating peptides to parathyroid hormone affects its structure, potency, and transepithelial permeation

Delivery of therapeutic peptides and proteins by the use of cell-penetrating peptides (CPPs) as carriers has been suggested as a feasible strategy. The aim of the present study was to investigate the effect of conjugating a series of well-known CPPs to the biologically active part of parathyroid hormone, i.e., PTH(1-34), and to evaluate the effect with regard to secondary structure, potency in Saos-2 cells, immunogenicity, safety, as well as the transepithelial permeation across monolayers by using the Caco-2 cell culture model. Further, co-administration of CPP and PTH(1-34) as an alternative to covalent conjugation was compared with regard to the transepithelial permeation. CPP-conjugated PTH(1-34) fusion peptides were successfully expressed in Escherichia coli and purified from inclusion bodies. No clear correlation between the degree of secondary structure of the CPP-conjugated PTH(1-34) fusion peptides and their potency was found, albeit a general decrease in permeation was observed for both N- and C-terminally CPP-conjugated PTH(1-34) as compared to native PTH(1-34). However, attachment of CPP to the N-terminus significantly increased permeation across Caco-2 cell monolayers as compared to the corresponding C-terminally CPP-conjugated PTH(1-34). In addition, the nonaarginine sequence proved to be the only CPP capable of increasing permeation when conjugated to PTH(1-34) as compared to co-administration of CPP and PTH(1-34). This enhancement effect was, however, associated with an unacceptably low level of cell viability. In conclusion, covalent conjugation of CPPs to PTH(1-34) influenced the secondary structure, potency, and transepithelial permeation efficiency of the resulting conjugate, and hence this approach appears not to be favorable as compared to co-administration when optimizing CPP-mediated permeation of PTH(1-34) across an intestinal epithelium.

Long-period gratings for selective monitoring of loads on a wind turbine blade

An optical fiber sensor based on long-period gratings (LPG) for selective measurements of flap- and edge-wise bending of a wind turbine blade is presented. Two consecutive LPGs separated by 40 mm interfere to improve resolution and reduce noise in a D-shaped fiber. The mode profile of the device was characterized experimentally to provide a model describing the mode couplings. The sensor was tested on a wind turbine blade.

Review: efficacy of alginate supplementation in relation to appetite regulation and metabolic risk factors: evidence from animal and human studies

This review provides a critical update on human and animal studies investigating the effect of alginate supplementation on appetite regulation, glycaemic and insulinemic responses, and lipid metabolism with discussion of the evidence on potential mechanisms, efficacy and tolerability. Dependent on vehicle applied for alginate supplementation, the majority of animal and human studies suggest that alginate consumption does suppress satiety and to some extent energy intake. Only one long-term intervention trial found effects on weight loss. In addition, alginates seem to exhibit beneficial influence on postprandial glucose absorption and insulin response in animals and humans. However, alginate supplementation was only found to have cholesterol-lowering properties in animals. Several mechanisms have been suggested for the positive effect observed, which involve delayed gastric emptying, increased viscosity of digesta and slowed nutrient absorption in the small intestine upon alginate gel formation. Despite reasonable efficacy and tolerability from the acute or short-term studies, we still realize there is a critical need for development of optimal alginate types and vehicles as well as studies on further long-term investigation on alginate supplementation in humans before inferring that it could be useful in the management of obesity and the metabolic syndrome.

Flaxseed dietary fibers suppress postprandial lipemia and appetite sensation in young men

BACKGROUND AND AIM

Dietary fibers (DF) are linked to a reduced risk of life-style diseases, which relate to their physiological effects in the gastrointestinal tract. The aim was to examine whether flaxseed DF-enriched meals suppress postprandial lipemia and reduce appetite.

METHODS AND RESULTS

Four different iso-caloric meals were tested in 18 young men in a double-blind randomized crossover design. Test meals were served after an overnight fast. DF content and source were: control (C): 1.4 g/MJ; whole flaxseed (WF): 2.4 g/MJ from whole flaxseeds; low-mucilage dose (LM): 2.4 g/MJ from flaxseed DF; high-mucilage dose (HM): 3.4 g/MJ from flaxseed DF. During the 7 h test day, subjective appetite sensation was assessed using visual analogue scales and appetite-regulating hormones, and lipemia and glycemia were measured, after which ad libitum energy intake was recorded. There was a significant time × meal effect on triacylglycerols (TG) (p = 0.02) and an 18% smaller area under the curve (AUC) for TG after meal HM compared to meal C was observed (p < 0.01). AUC for insulin was smaller after both LM and HM meals compared to C and WF meals. Higher mean ratings of satiety (p < 0.01) and fullness (p = 0.03) was seen following the HM meal compared to meal C. AUC for ghrelin, CCK and GLP-1 and ad libitum energy intake did not differ between meals, but ghrelin response exhibited a different response pattern after the mucilage-containing meals.

CONCLUSION

These findings suggest that flaxseed DF may suppress postprandial lipemia and appetite although subsequent energy intake was not affected.

Effects of dietary fibre on subjective appetite, energy intake and body weight: a systematic review of randomized controlled trials

Dietary fibres are believed to reduce subjective appetite, energy intake and body weight. However, different types of dietary fibre may affect these outcomes differently. The aim of this review was to systematically investigate the available literature on the relationship between dietary fibre types, appetite, acute and long-term energy intake, and body weight. Fibres were grouped according to chemical structure and physicochemical properties (viscosity, solubility and fermentability). Effect rates were calculated as the proportion of all fibre-control comparisons that reduced appetite (n = 58 comparisons), acute energy intake (n = 26), long-term energy intake (n = 38) or body weight (n = 66). For appetite, acute energy intake, long-term energy intake and body weight, there were clear differences in effect rates depending on chemical structure. Interestingly, fibres characterized as being more viscous (e.g. pectins, β-glucans and guar gum) reduced appetite more often than those less viscous fibres (59% vs. 14%), which also applied to acute energy intake (69% vs. 30%). Overall, effects on energy intake and body weight were relatively small, and distinct dose-response relationships were not observed. Short- and long-term effects of dietary fibres appear to differ and multiple mechanisms relating to their different physicochemical properties seem to interplay. This warrants further exploration.

Cell transformation mediated by the Epstein-Barr virus G protein-coupled receptor BILF1 is dependent on constitutive signaling

Epstein-Barr virus (EBV) open reading frame BILF1 encodes a seven trans-membrane (TM) G protein-coupled receptor that signals with high constitutive activity through Galpha(i) (Beisser et al., 2005; Paulsen et al., 2005). In this paper, the transforming potential of BILF1 is investigated in vitro in a foci formation assay using retrovirally transduced NIH3T3 cells, as well as in vivo by using nude mice. BILF1 revealed a substantial transforming potential that was dependent on constitutive signaling, as a signaling-deficient mutant completely lost its ability to transform cells in vitro, and an intermediately active triple-mutated receptor possessed an intermediate transforming potential. Furthermore, BILF1 expression induced vascular endothelial growth factor secretion in a constitutively active manner. In nude mice, BILF1 promoted tumor formation in 90% of cases, ORF74 (from Kaposi's sarcoma-associated herpes virus) in 100% of cases, whereas the signaling-deficient receptor resulted in tumor establishment in 40% of cases. These data suggest that BILF1, when expressed during EBV infection, could indeed be involved in the pathogenesis of EBV-associated diseases and malignancies. Furthermore, the correlation between receptor activity and the ability to mediate cell transformation in vitro and tumor formation in vivo supports the idea that inverse agonists for BILF1 could inhibit cell transformation and be relevant therapeutic candidates.

Potassium-transporting proteins in skeletal muscle: cellular location and fibre-type differences

Abstract Potassium (K(+)) displacement in skeletal muscle may be an important factor in the development of muscle fatigue during intense exercise. It has been shown in vitro that an increase in the extracellular K(+) concentration ([K(+)](e)) to values higher than approx. 10 mm significantly reduce force development in unfatigued skeletal muscle. Several in vivo studies have shown that [K(+)](e) increases progressively with increasing work intensity, reaching values higher than 10 mm. This increase in [K(+)](e) is expected to be even higher in the transverse (T)-tubules than the concentration reached in the interstitium. Besides the voltage-sensitive K(+) (K(v)) channels that generate the action potential (AP) it is suggested that the big-conductance Ca(2+)-dependent K(+) (K(Ca)1.1) channel contributes significantly to the K(+) release into the T-tubules. Also the ATP-dependent K(+) (K(ATP)) channel participates, but is suggested primarily to participate in K(+) release to the interstitium. Because there is restricted diffusion of K(+) to the interstitium, K(+) released to the T-tubules during AP propagation will be removed primarily by reuptake mediated by transport proteins located in the T-tubule membrane. The most important protein that mediates K(+) reuptake in the T-tubules is the Na(+),K(+)-ATPase alpha(2) dimers, but a significant contribution of the strong inward rectifier K(+) (Kir2.1) channel is also suggested. The Na(+), K(+), 2Cl(-) 1 (NKCC1) cotransporter also participates in K(+) reuptake but probably mainly from the interstitium. The relative content of the different K(+)-transporting proteins differs in oxidative and glycolytic muscles, and might explain the different [K(+)](e) tolerance observed.

Choreoathetosis during phenytoin treatment

A patient with symptomatic epilepsy receiving only phenytoin developed choreoathetosis and orofacial dyskinesias. These movement disorders disappeared when the drug was stopped and reappeared when the patient was challenged. Throughout the period of treatment, concentrations of phenytoin in serum were consistently low within the therapeutic range. Interfering symptoms from the cardiovascular system and the absence of some classic symptoms of phenytoin intoxication (nystagmus and dysarthria) contributed to delay the diagnosis. The patient died in hospital and autopsy of the brain showed rather localized encephalomalacies of corpus striatum. The pathogenic action of phenytoin and the role of preexisting brain lesions are discussed. Phenytoin must be suspected as the cause, when patients on this drug present with uncontrolllable epilepsy or neurological or mental deterioration.

The effect of different oral anticoagulants on diphenylhydantoin (DPH) and tolbutamide metabolism

The effect of bishydroxycoumarin, phenprocoumon, warfarin and phenindione on the metabolism of diphenylhydantoin (DPH) and tolbutamide has been studied in 54 patients. The half-lives of DPH and tolbutamide in blood following i.v. injections were studied in 33 patients before and after one week of anticoagulant treatment. Bishydroxycoumarin increased the mean half-life values of DPH from 8.8 to 37.4 hours and of tolbutamide from 4.9 to 17.5. Phenprocoumon prolonged DPH half-life from a mean value of 9.9 to 14.0 hours but did not change the tolbutamide half-life. Warfarin and phenindione did not affect DPH or tolbutamide half-lives. Steady state concentration studies in 21 patients showed a rise in serum DPH during bishydroxycoumarin and phenprocoumon treatment but not during treatment with warfarin and phenindione. A rise in serum tolbutamide was noted during treatment with bishydroxycoumarin. These findings suggest that bishydroxycoumarin inhibits the betabolism of DPH and tolbutamide and that phenprocoumon inhibits DPH metabolism. No effect on DPH and tolbutamide metabolism could be demonstrated following administration of warfarin and phenindione.

A case for sequencing the genome of Musca domestica (Diptera: Muscidae)

House flies are carriers of >100 devastating diseases that have severe consequences for human and animal health. Despite the fact that it is a passive vector, a key bottleneck to progress in controlling the human diseases transmitted by house flies is lack of knowledge of the basic molecular biology of this species. Sequencing of the house fly genome will provide important inroads to the discovery of novel target sites for house fly control, understanding of the house fly immune response, rapid elucidation of insecticide resistance genes, and understanding of numerous aspects of the basic biology of this insect pest. The ability of the house fly to prosper in a remarkably septic environment motivates analysis of its innate immune system. Its polymorphic sex determination system, with male-determining factors on either the autosomes or the Y chromosome, is ripe for a genomic analysis. Sequencing of the house fly genome would allow the first opportunity to study the interactions between a pest insect and its parasitoid (Nasonia vitripennis) at the whole genome level. In addition, the house fly is well placed phylogenetically to leverage analysis of the multiple Dipteran genomes that have been sequenced (including several mosquito and Drosophila species). The community of researchers investigating Musca domestica are well prepared and highly motivated to apply genomic analyses to their widely varied research programs.

Ice-active proteins and cryoprotectants from the New Zealand alpine cockroach, Celatoblatta quinquemaculata

Celatoblatta quinquemaculata is moderately freezing tolerant. We have investigated low and high molecular weight compounds that may be associated with its survival. Glycerol and trehalose were identified as potential cryoprotectants, with trehalose at the higher concentration. Trehalose was at its highest concentration in late autumn, during the periods sampled. Water contents declined with time and were significantly lower in late autumn than in late summer. No thermal hysteresis activity was detected in haemolymph or in extracts of the head, muscles and the fat body. Extracts of the Malpighian tubules showed an hexagonal crystal growth form, as did those of the gut tissue and gut contents. The gut tissue had high levels of thermal hysteresis (approximately 2 degrees C) and the gut contents somewhat lower levels (approximately 0.6 degrees C). Recrystallization inhibition activity mirrored that of thermal hysteresis, with activity absent in the haemolymph or fat body cells but present in the gut tissues and contents. Activity was reduced by heating and was associated with a molecule >14kDa in size. These findings suggest an antifreeze protein is involved. In fed animals, ice nucleation is likely to start in the gut. Gut cells have a much greater resistance to freezing than do fat body or Malpighian tubule cells. The antifreeze protein may enable this tissue to survive freezing stress by inhibiting recrystallization.

Exercise-induced regulation of phospholemman (FXYD1) in rat skeletal muscle: implications for Na+/K+-ATPase activity

BACKGROUND

Na(+)/K(+)-ATPase activity is upregulated during muscle exercise to maintain ionic homeostasis. One mechanism may involve movement of alpha-subunits to the outer membrane (translocation).

AIM

We investigated the existence of exercise-induced translocation and phosphorylation of phospholemman (PLM, FXYD1) protein in rat skeletal muscle and exercise-induced changes in V(max) and K(m) for Na(+) of the Na(+)/K(+)-ATPase.

METHODS

Two membrane fractionation methods and immunoprecipitation were used.

RESULTS

Both fractionation methods revealed a 200-350% increase in PLM in the sarcolemma after 30 min of treadmill running, while the phosphorylation of Ser-68 of PLM appeared to be unchanged. Exercise did not change V(max) or K(m) for Na(+) of the Na(+)/K(+)-ATPase in muscle homogenate, but induced a 67% increase in V(max) in the sarcolemmal giant vesicle preparation; K(m) for Na(+) remained constant. The main part of the increase in V(max) is related to a 36-53% increase in the level of alpha-subunits; the remainder may be related to increased PLM content. Similar results were obtained with another membrane purification method. In resting muscle, 29% and 32% of alpha(1)- and alpha(2)-subunits, respectively, were co-immunoprecipitated by PLM antibodies. In muscle homogenate prepared after exercise, immunoprecipitation of alpha(1)-subunits was increased to 227%, whereas the fraction of precipitated alpha(2) remained constant.

CONCLUSION

Exercise translocates PLM to the muscle outer membrane and increases its association with mainly the alpha(1)-subunit, which may contribute to the increased V(max) of the Na(+)/K(+)-ATPase.

Whole flaxseeds but not sunflower seeds in rye bread reduce apparent digestibility of fat in healthy volunteers

OBJECTIVE

The aim of this study was to measure the apparent digestibility of fat and the transit time upon addition of whole sunflower seeds (SU) or flaxseeds (FL) to rye breads consumed as part of a whole diet.

METHOD

In a randomized crossover study, gross intake and faecal excretion of fat and energy were measured in 11 young healthy men aged 24.6+/-2.7 years. During each 7 days intervention periods, the subjects received a basal diet plus 300 g of one of four rye breads: (1) rye bread; (2) rye bread with SU; (3) rye bread with FL; (4) low extraction rate rye bread with SU and FL. Fat binding properties of rye breads (1) and (3) were determined by in vitro digestion.

RESULTS

Addition of whole SU or FL to breads increased daily gross intake of fat and energy (P<0.001). The amounts of apparently digested fat (g/day) and energy were lowered when subjects consumed the SU or FL rye bread (P<0.001). The effect on energy digestibility of FL was more pronounced than that of SU. The in vitro fat digestibility of rye breads and whole diets show fat-binding properties of FL when compared to the rye bread diet (P<0.05).

CONCLUSIONS

Enrichment of bread with whole FL does not appear to result in increased fat and energy intake when added to breads, but the results rather indicate an impairment of nutrient utilization.