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"Sax, A"
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Increased bioavailability of curcumin using a novel dispersion technology system (LipiSperse®)
PurposeCurcumin has been shown to deliver protective effects against numerous degenerative conditions associated with high levels of inflammation and oxidative stress. Owing to its poor bioavailability when delivered orally, it is difficult to deliver a high concentration therapeutic dose. LipiSperse® is a novel delivery system that uses dispersion technology to enhance bioavailability of hydrophobic agents. In this study, we investigated the pharmacokinetics of a commercially available curcumin extract, with or without the curcumin-LipiSperse® delivery complex.MethodsEighteen healthy male and female volunteers participated in this single equivalent dose, randomised, double-blinded study. Seven of those volunteers further participated in the crossover phase of the trial. Plasma concentrations were determined at baseline and at regular intervals over a 24-h period following 750 mg of curcuminoid ingestion.ResultsIn both the parallel and crossover trial, Curcumin with LipiSperse® delivered significantly higher plasma curcuminoid concentrations compared to the raw curcumin product (807 vs 318 ng/mL in the crossover trial).ConclusionsThe novel delivery system LipiSperse® is safe in humans, and demonstrates superior bioavailability for the supply of curcumin when compared to a standard curcumin extract.
Journal Article
Molecular heterometallic hydride clusters composed of rare-earth and d-transition metals
Heteromultimetallic hydride clusters containing both rare-earth and
d
-transition metals are of interest in terms of both their structure and reactivity. However, such heterometallic complexes have not yet been investigated to a great extent because of difficulties in their synthesis and structural characterization. Here, we report the synthesis, X-ray and neutron diffraction studies, and hydrogen addition and release properties of a family of rare-earth/
d
-transition-metal heteromultimetallic polyhydride complexes of the core structure type ‘Ln
4
MH
n
’ (Ln = Y, Dy, Ho; M = Mo, W;
n
= 9, 11, 13). Monitoring of hydrogen addition to a hydride cluster such as [{(C
5
Me
4
SiMe
3
)Y}
4
(
μ
-H)
9
Mo(C
5
Me
5
)] in a single-crystal to single-crystal process by X-ray diffraction has been achieved for the first time. Density functional theory studies reveal that the hydrogen addition process is cooperatively assisted by the Y/Mo heteromultimetallic sites, thus offering unprecedented insight into the hydrogen addition and release process of a metal hydride cluster.
Well-defined molecular polyhydrides composed of two substantially different types of metals — such as rare-earth and
d
transition metals — are interesting both in terms of structure and potential properties, but have been largely unexplored so far. Now, a series of such hydride clusters are reported and are found to exhibit unprecedented structural features as well as unique hydrogen addition and release properties.
Journal Article
Macromolecular structure phasing by neutron anomalous diffraction
In this report we show for the first time that neutron anomalous dispersion can be used in a practical manner to determine experimental phases of a protein crystal structure, providing a new tool for structural biologists. The approach is demonstrated through the use of a state-of-the-art monochromatic neutron diffractometer at the Institut Laue-Langevin (ILL) in combination with crystals of perdeuterated protein that minimise the level of hydrogen incoherent scattering and enhance the visibility of the anomalous signal. The protein used was rubredoxin in which cadmium replaced the iron at the iron-sulphur site. While this study was carried out using a steady-state neutron beam source, the results will be of major interest for capabilities at existing and emerging spallation neutron sources where time-of-flight instruments provide inherent energy discrimination. In particular this capability may be expected to offer unique opportunities to a rapidly developing structural biology community where there is increasing interest in the identification of protonation states, protein/water interactions and protein-ligand interactions – all of which are of central importance to a wide range of fundamental and applied areas in the biosciences.
Journal Article
Binding site asymmetry in human transthyretin: insights from a joint neutron and X-ray crystallographic analysis using perdeuterated protein
Human transthyretin has an intrinsic tendency to form amyloid fibrils and is heavily implicated in senile systemic amyloidosis. Here, detailed neutron structural studies of perdeuterated transthyretin are described. The analyses, which fully exploit the enhanced visibility of isotopically replaced hydrogen atoms, yield new information on the stability of the protein and the possible mechanisms of amyloid formation. Residue Ser117 may play a pivotal role in that a single water molecule is closely associated with the γ-hydrogen atoms in one of the binding pockets, and could be important in determining which of the two sites is available to the substrate. The hydrogen-bond network at the monomer–monomer interface is more extensive than that at the dimer–dimer interface. Additionally, the edge strands of the primary dimer are seen to be favourable for continuation of the β-sheet and the formation of an extended cross-β structure through sequential dimer couplings. It is argued that the precursor to fibril formation is the dimeric form of the protein.
Journal Article
The influence of high-intensity compared with moderate-intensity exercise training on cardiorespiratory fitness and body composition in colorectal cancer survivors: a randomised controlled trial
Purpose
Following colorectal cancer diagnosis and anti-cancer therapy, declines in cardiorespiratory fitness and body composition lead to significant increases in morbidity and mortality. There is increasing interest within the field of exercise oncology surrounding potential strategies to remediate these adverse outcomes. This study compared 4 weeks of moderate-intensity exercise (MIE) and high-intensity exercise (HIE) training on peak oxygen consumption (V̇O
2
peak) and body composition in colorectal cancer survivors.
Methods
Forty seven post-treatment colorectal cancer survivors (HIE = 27 months post-treatment; MIE = 38 months post-treatment) were randomised to either HIE [85–95 % peak heart rate (HR
peak
)] or MIE (70 % HR
peak
) in equivalence with current physical activity guidelines and completed 12 training sessions over 4 weeks.
Results
HIE was superior to MIE in improving absolute (
p
= 0.016) and relative (
p
= 0.021) V̇O
2
peak. Absolute (+0.28 L.min
−1
,
p
< 0.001) and relative (+3.5 ml.kg
−1
.min
−1
,
p
< 0.001) V̇O
2
peak were increased in the HIE group but not the MIE group following training. HIE led to significant increases in lean mass (+0.72 kg,
p
= 0.002) and decreases in fat mass (−0.74 kg,
p
< 0.001) and fat percentage (−1.0 %,
p
< 0.001), whereas no changes were observed for the MIE group. There were no severe adverse events.
Conclusions
In response to short-term training, HIE is a safe, feasible and efficacious intervention that offers clinically meaningful improvements in cardiorespiratory fitness and body composition for colorectal cancer survivors.
Implications for Cancer Survivors
HIE appears to offer superior improvements in cardiorespiratory fitness and body composition in comparison to current physical activity recommendations for colorectal cancer survivors and therefore may be an effective clinical utility following treatment.
Journal Article
Molecular simulation of surface reorganization and wetting in crystalline cellulose I and II
Cellulose is one of the most versatile substances in the world. Its immense variety of applications was in recent years complemented by nanotechnological applications such as cellulose nanoparticle dressed surfaces for filtration purposes or cellulose matrices for microelectronics. The fabrication of such complex materials asks for thorough understanding of the surface structure and its interactions with adsorbates. In this study we investigate several surface model systems of nanotechnological interest, which are obtained by reorganization of the cellulose-vacuum or cellulose-water interfaces of slabs of crystalline cellulose. To do this, we equilibrated first bulk supercells of different cellulose allomorphs, which were constructed from crystallographic data, and then optimized the interface structures. From the bulk and surface systems we calculated structural properties such as unit cell parameters, dihedral conformation distributions, density profiles and hydrogen bonding. The results suggest that no overall geometrical restructuring occurs at the interface. However, the hydrogen bond network is strongly reconstructed, as is inferred from the dihedral conformations and hydrogen bond occurrences, although only within the first few layers. This holds for low index close packed structures as well as for high index loosely packed surfaces. Replacing the vacuum by ambient pressure water molecules we find less rearrangements of the cellulose surface, because the water allows formation of hydrogen bonds similar to those in the bulk phase. The water near the cellulose surface shows, however, strong structural changes. We observe reduced mobility of the water molecules, which corresponds to a cooling of water by about 30°, in a slab that is about 10 Å thick. Although structuring and adsorption is observed on all surfaces, no actual penetration of water into the cellulose structure could be observed. This suggests that pure water is not sufficient to produce cellulose swelling at mesoscopic timescales. This work lays the basis for current quantum chemical investigations on specific interaction terms within cellulose.
Journal Article
Neutron Diffraction Analysis of H3Co2C5H2(t-Bu)32, a Molecule with a Triply Hydrogen-Bridged Metal–Metal Bond: Some Comments on Structural Patterns in M(μ-H)nM Systems (n=1, 2, 3, 4)
The structure of H3Co2[C5H2(t-Bu)3]2 has been analyzed by low-temperature single-crystal neutron diffraction techniques, and shown to consist of two CoCp‡ moieties with three hydride ligands bridging the central Co–Co bond. Despite a fairly extensive twinning problem, the structure could be solved and successfully refined to a final R factor of 9.2% for 2024 reflections. Average molecular parameters in the H3Co2 core of the molecule are as follows: Co–Co=2.275(21) Å, Co–H=1.637(16) Å, H⋯H=2.050(20) Å, Co–H–Co=88.0(9)°, H–Co–H=77.0(7)°. Also included in this paper is a discussion on the molecular dimensions of symmetric hydride-bridged dinuclear systems (M(μ-H)nM, n=1, 2, 3, 4) that have been studied to date by neutron diffraction.
Journal Article
Individual and Temporal Variation in Cloacal Protuberance Size of Male Bearded Tits (Panurus biarmicus)
The intensity of sperm competition is one of the factors known to determine interspecific variation in the size of male reproductive organs. However, individual variation in the size of reproductive organs and its relation to male quality have not been considered appropriately. We investigated the annual pattern of variation in the size of the cloacal protuberance (CP) in male Bearded Tits (Panurus biarmicus) and correlated CP volume during the fertile period of females with reproductive and morphological features of males. Contrary to other passerines, the cloacal protuberance does not constitute a sperm reservoir but functions as a copulatory organ in Bearded Tits. CP volume differed significantly between unmated and mated males and provided a good indicator of their reproductive status. Within individual mated Bearded Tits, CP size changed in conjunction with their mate's fertile cycle, peaking around the day of clutch initiation. During the fertile period, mated Bearded Tits possess the largest CP (relative to body size) known for a passerine (average volume index = 59.14 mm3per g; n = 16). The adaptive value of this feature could be that it improves ejaculate transfer owing to better and longer cloacal contact. Relative to unmated males, mated males have more total sperm stored in their seminal glomera and larger testes, suggesting the occurrence of large disadvantages for unmated males to gain reproductive success. An isolation experiment showed that female presence positively influences the development of CP size in virgin male Bearded Tits.
Journal Article
