No effect of acute tetrahydrobiopterin (BH4) supplementation on vascular dysfunction in the old.

As a deficiency in tetrahydrobiopterin (BH4), a cofactor for endothelial nitric oxide synthase, has been implicated in the age-related decline in vascular function, this study aimed to determine the impact of acute BH4 supplementation on flow-mediated vasodilation (FMD) in old adults. Two approaches were used: 1) A multiday, double-blind, placebo-controlled, crossover design measuring, FMD [ΔFMD (mm), %FMD (%)] and shear rate area under the curve (SR AUC) in nine old subjects (73 ± 8 yr) with either placebo (placebo) or BH4 (≈10 mg/kg, post), and 2) a single experimental day measuring FMD in an additional 13 old subjects (74 ± 7 yr) prior to (pre) and 4.5 h after ingesting BH4 (≈10 mg/kg). With the first experimental approach, acute BH4 intake did not significantly alter FMD (ΔFMD: 0.17 ± 0.03 vs. 0.13 ± 0.02 mm; %FMD: 3.3 ± 0.61 vs. 2.9 ± 0.4%) or SR AUC (30,280 ± 4,428 vs. 37,877 ± 9,241 s-1) compared with placebo. Similarly, with the second approach, BH4 did not significantly alter FMD (ΔFMD: 0.09 ± 0.02 vs. 0.12 ± 0.03 mm; %FMD: 2.2 ± 0.6 vs. 2.9 ± 0.6%) or SR AUC (37,588 ± 6,753 vs. 28,996 ± 3,735 s-1) compared with pre. Moreover, when the two data sets were combined, resulting in a greater sample size, there was still no evidence of an effect of BH4 on vascular function in these old subjects. Importantly, both plasma BH4 and 7,8-dihydrobiopterin (BH2), the oxidized form of BH4, increased significantly with acute BH4 supplementation. Consequently, the ratio of BH4/BH2, recognized to impact vascular function, was unchanged. Thus, acute BH4 supplementation does not correct vascular dysfunction in the old.NEW & NOTEWORTHY Despite two different experimental approaches, acute BH4 supplementation did not affect vascular function in older adults, as measured by flow-mediated vasodilation. Plasma levels of both BH4 and BH2, the BH4 oxidized form, significantly increased after acute BH4 supplementation, resulting in an unchanged ratio of BH4/BH2, a key determining factor for endothelial nitric oxide synthase coupling. Therefore, likely due to the elevated oxidative stress with advancing age, acute BH4 supplementation does not correct vascular dysfunction in the old.

Influence of physical properties on the taste and flavor of strawberry jam.

This study investigated the influence of the type and concentration of pectin on the sensory attributes and physical properties of a model strawberry jam. The methods used for the sensory evaluation and determination of physical characteristics that affect human taste and flavor perception are outlined. Increasing pectin concentration altered the solid (elastic) properties of the model strawberry jam. Each sensory attribute showed high correlation with various physical properties as determined by viscosity measurements. These results allowed us to predict the human oral cavity conditions during taste and flavor perception. From this study, it is clear that humans assess the physical properties of foods by the tongue movements and adjustments in the oral cavity conditions according to the taste and flavor characteristics.

Preparation and Characterization of Emulsion-based Peony Seed Oil Microcapsule.

Microcapsules were constructed with starch sodium octenyl succinate (SSOS), ß-cyclodextrin (ß-CD), and pectin walls and peony seed oil cores. A rheological phenomenon occurred in which the emulsion initially behaved like a shear-thickening fluid and then a shear-thinning fluid within a shear range. The emulsion exhibited good stability under low amplitude stress; however, as amplitude increased the concentration of pectin played an important role in maintaining the stability of the emulsion system. The optimum embedding yield of peony seed oil (92.5%) was achieved with a ratio of 70% SSOS, 22.5% ß-CD, and 7.5% pectin. This ratio produced 4.521 µm particles with the lowest surface-oil content (2.60%) and moisture content (1.76%). The peony seed oil microcapsules were spherical with smooth surfaces and a synchronous thermogravimetric analysis showed they possessed good thermal stability. Encapsulation increased the induction period to 5-7 times that of unencapsulated peony seed oil.

Combined effect of shearing and cooling rate on the rheology of organogels developed by selected gelators.

In this study we investigated the combined effect of shearing and cooling rate in the rheology of organogels developed in high oleic safflower oil by (R)-12-hydroxystearic acid (HSA), its primary amide derivative [(R)-12-hydroxyoctadecanamide, HOA], and the N-octadecyl derivative of HOA [(R)-N-octadecyl-12-hydroxyoctadecanamide, OHOA]. The experimental set up to develop the organogels involved: 1). The use of quiescent (0s-1) or shearing (300, 600, and 1200s-1) conditions during cooling the gelator solutions (2%) just until achieving the gelator's melting temperature (TM) in the vegetable oil, to then continuing the cooling under static conditions until achieving 15°C) The use of cooling rate protocols involving a constant cooling rate of 1°C/min (CR1) or 10°C/min (CR10) in the shearing and static stages, or variable cooling rates in each stage (i.e., VR1-10 or VR10-1). The elasticity of the organogels (G') was measured while cooling under static conditions, once the systems achieved 15°C, and after 60min at this temperature. The rheological results obtained at 15°C showed a cooling rate and molecular weight-dependent effect of shearing on G'. We propose that the molecular relaxation time of gelator molecules, and its increase as molecular weight increases and as temperature decreases, plays an important role on the gelator's susceptibility to go through a shear induced crystallization process. Therefore, high molecular weight molecules like OHOA (551.97Da) would remain stretched by shearing longer times than HSA (300.49Da) and HOA (299.49Da). Thus, when shearing was applied while cooling at the higher cooling rate (i.e., CR10 and VR10-1), the stretched OHOA molecules would lead to the development of mesophase precursors that upon further cooling under quiescent conditions, crystallize developing a well-structured organogel. In contrast, stretched low molecular weight molecules (i.e., HSA and HOA) with shorter relaxation time would dissolve back to the isotropic state during cooling. Additionally, the rheological results of HSA and HOA organogels suggested that the shear induced crystallization process might be dependent on the gelator polarity also. These results show that the application of shear and the extent of its application as temperature decreases until achieving TM, have important implication on the self-assembly of gelator molecules, and therefore in the organization and rheology of the three-dimensional crystal network of the organogel.

Lower-limb hot-water immersion acutely induces beneficial hemodynamic and cardiovascular responses in peripheral arterial disease and healthy, elderly controls.

Passive heat induces beneficial perfusion profiles, provides substantive cardiovascular strain, and reduces blood pressure, thereby holding potential for healthy and cardiovascular disease populations. The aim of this study was to assess acute responses to passive heat via lower-limb, hot-water immersion in patients with peripheral arterial disease (PAD) and healthy, elderly controls. Eleven patients with PAD (age 71 ± 6 yr, 7 male, 4 female) and 10 controls (age 72 ± 7 yr, 8 male, 2 female) underwent hot-water immersion (30-min waist-level immersion in 42.1 ± 0.6°C water). Before, during, and following immersion, brachial and popliteal artery diameter, blood flow, and shear stress were assessed using duplex ultrasound. Lower-limb perfusion was measured also using venous occlusion plethysmography and near-infrared spectroscopy. During immersion, shear rate increased (P < 0.0001) comparably between groups in the popliteal artery (controls: +183 ± 26%; PAD: +258 ± 54%) and brachial artery (controls: +117 ± 24%; PAD: +107 ± 32%). Lower-limb blood flow increased significantly in both groups, as measured from duplex ultrasound (>200%), plethysmography (>100%), and spectroscopy, while central and peripheral pulse-wave velocity decreased in both groups. Mean arterial blood pressure was reduced by 22 ± 9 mmHg (main effect P < 0.0001, interaction P = 0.60) during immersion, and remained 7 ± 7 mmHg lower 3 h afterward. In PAD, popliteal shear profiles and claudication both compared favorably with those measured immediately following symptom-limited walking. A 30-min hot-water immersion is a practical means of delivering heat therapy to PAD patients and healthy, elderly individuals to induce appreciable systemic (chronotropic and blood pressure lowering) and hemodynamic (upper and lower-limb perfusion and shear rate increases) responses.