How Low Can You Go? The Radiobiology of Hypofractionation.

Hypofractionated radical radiotherapy is now an accepted standard of care for tumour sites such as prostate and breast cancer. Much research effort is being directed towards more profoundly hypofractionated (ultrahypofractionated) schedules, with some reaching UK standard of care (e.g. adjuvant breast). Hypofractionation exerts varying influences on each of the major clinical end points of radiotherapy studies: acute toxicity, late toxicity and local control. This review will discuss these effects from the viewpoint of the traditional 5 Rs of radiobiology, before considering non-canonical radiobiological effects that may be relevant to ultrahypofractionated radiotherapy. The principles outlined here may assist the reader in their interpretation of the wealth of clinical data presented in the tumour site-specific articles in this special issue.

Development of Tri-Layered Biomimetic Atelocollagen Scaffolds with Interfaces for Osteochondral Tissue Engineering.

The development of biomimetic scaffolds containing cartilage, calcified cartilage, and bone regeneration for precise osteochondral repair remains a challenge. Herein, a novel tri-layered scaffold-with a top layer containing type II atelocollagen and chondroitin sulphate for cartilage regeneration, an intermediate layer with type II atelocollagen and hydroxyapatite for calcified cartilage formation, and a bottom layer with type I atelocollagen and hydroxyapatite for bone growth-that can be built using liquid-phase cosynthesis, is described. The tri-layered scaffolds are mechanically demonstrably superior and have a lower risk of delamination than monolayer scaffolds. This is due to higher cohesion arising from the interfaces between each layer. In vitro results show that although monolayer scaffolds can stimulate bone marrow stem cells to differentiate and form cartilage, calcified cartilage, and bone separately (detected using quantitative polymerase chain reaction analysis and staining with safranin-O and Alizarin Red S), the tri-layered scaffolds support the regeneration of cartilage, calcified cartilage, and bone simultaneously after 2 and 4 months of implantation (detected using gross and micro-computed tomography images, histological staining, and Avizo, a software used to detect microlevel defects in metals). This work presents data on a promising approach in devising strategies for the precise repair of osteochondral defects.

What Can Proton Beam Therapy Achieve for Patients with Pectus Excavatum Requiring Left Breast, Axilla and Internal Mammary Nodal Radiotherapy?

AIMS: Exposure of the heart to radiation increases the risk of ischaemic heart disease, proportionate to the mean heart dose (MHD). Radiotherapy techniques including proton beam therapy (PBT) can reduce MHD. The aims of this study were to quantify the MHD reduction achievable by PBT compared with volumetric modulated arc therapy in breath hold (VMAT-BH) in patients with pectus excavatum (PEx), to identify an anatomical metric from a computed tomography scan that might indicate which patients will achieve the greatest MHD reductions from PBT. MATERIALS AND METHODS: Sixteen patients with PEx (Haller Index ≥2.7) were identified from radiotherapy planning computed tomography images. Left breast/chest wall, axilla (I-IV) and internal mammary node (IMN) volumes were delineated. VMAT and PBT plans were prepared, all satisfying target coverage constraints. Signed-rank comparisons of techniques were undertaken for the mean dose to the heart, ipsilateral lung and contralateral breast. Spearman's rho correlations were calculated for anatomical metrics against MHD reduction achieved by PBT. RESULTS: The mean MHD for VMAT-BH plans was 4.1 Gy compared with 0.7 Gy for PBT plans. PBT reduced MHD by an average of 3.4 Gy (range 2.8-4.4 Gy) compared with VMAT-BH (P < 0.001). PBT significantly reduced the mean dose to the ipsilateral lung (4.7 Gy, P < 0.001) and contralateral breast (2.7 Gy, P < 0.001). The distance (mm) at the most inferomedial extent of IMN volume (IMN to heart distance) negatively correlated with MHD reduction achieved by PBT (Spearman's rho -0.88 (95% confidence interval -0.96 to -0.67, P < 0.001)). CONCLUSION: For patients with PEx requiring left-sided breast and IMN radiotherapy, a clinically significant MHD reduction is achievable using PBT, compared with the optimal photon technique (VMAT-BH). This is a patient group in whom PBT could have the greatest benefit.

Detailed Phenolic Characterization of Protea Pure and Hybrid Cultivars by Liquid Chromatography-Ion Mobility-High Resolution Mass Spectrometry (LC-IM-HR-MS).

In this study we report a detailed investigation of the polyphenol composition of Protea pure (P. cynaroides and P. neriifolia) and hybrid cultivars (Black beauty and Limelight). Aqueous methanol extracts of leaf and bract tissues were analyzed by ultrahigh pressure liquid chromatography hyphenated to photodiode array and ion mobility-high resolution mass spectrometric (UHPLC-PDA-IM-HR-MS) detection. A total of 67 metabolites were characterized based on their relative reversed phase (RP) retention, UV-vis spectra, low and high collision energy HR-MS data, and collisional cross section (CCS) values. These metabolites included 41 phenolic acid esters and 25 flavonoid derivatives, including 5 anthocyanins. In addition, an undescribed hydroxycinnamic acid-polygalatol ester, caffeoyl-O-polygalatol (1,5-anhydro-[6-O-caffeoyl]-sorbitol(glucitol)) was isolated and characterized by 1D and 2D NMR for the first time. This compound and its isomer are shown to be potential chemo-taxonomic markers.

Roots and Nodules Response Differently to P Starvation in the Mediterranean-Type Legume Virgilia divaricata.

Virgilia divaricata is a tree legume that grows in the Cape Floristic Region (CFA) in poor nutrient soils. A comparison between high and low phosphate growth conditions between roots and nodules was conducted and evaluated for the plants ability to cope under low phosphate stress conditions in V. divaricata. We proved that the plant copes with low phosphate stress through an increased allocation of resources, reliance on BNF and enhanced enzyme activity, especially PEPC. Nodules had a lower percentage decline in P compared to roots to uphold its metabolic functions. These strategies partly explain how V. divaricata can sustain growth despite LP conditions. Although the number of nodules declined with LP, their biomass remained unchanged in spite of a plant decline in dry weight. This is achieved via the high efficiency of BNF under P stress. During LP, nodules had a lower % decline at 34% compared to the roots at 88%. We attribute this behavior to P conservation strategies in LP nodules that imply an increase in a metabolic bypass that operates at the PEP branch point in glycolysis. The enhanced activities of nodule PEPC, MDH, and ME, whilst PK declines, suggests that under LP conditions an adenylate bypass was in operation either to synthesize more organic acids or to mediate pyruvate via a non-adenylate requiring metabolic route. Both possibilities represent a P-stress adaptation route and this is the first report of its kind for legume trees that are indigenous to low P, acid soils. Although BNF declined by a small percentage during LP, this P conservation was evident in the unchanged BNF efficiency per weight, and the increase in BNF efficiency per mol of P. It appears that legumes that are indigenous to acid soils, may be able to continue their reliance on BNF via increased allocation to nodules and also due to increase their efficiency for BNF on a P basis, owing to P-saving mechanisms such as the organic acid routes.

Iron diapirs entrain silicates to the core and initiate thermochemical plumes.

Segregation of the iron core from rocky silicates is a massive evolutionary event in planetary accretion, yet the process of metal segregation remains obscure, due to obstacles in simulating the extreme physical properties of liquid iron and silicates at finite length scales. We present new experimental results studying gravitational instability of an emulsified liquid gallium layer, initially at rest at the interface between two glucose solutions. Metal settling coats liquid metal drops with a film of low density material. The emulsified metal pond descends as a coherent Rayleigh-Taylor instability with a trailing fluid-filled conduit. Scaling to planetary interiors and high pressure mineral experiments indicates that molten silicates and volatiles are entrained toward the iron core and initiate buoyant thermochemical plumes that later oxidize and hydrate the upper mantle. Surface volcanism from thermochemical plumes releases oxygen and volatiles linking atmospheric growth to the Earth's mantle and core processes.

Monomeric, porous type II collagen scaffolds promote chondrogenic differentiation of human bone marrow mesenchymal stem cells in vitro.

Osteoarthritis (OA) is a common cause of pain and disability and is often associated with the degeneration of articular cartilage. Lesions to the articular surface, which are thought to progress to OA, have the potential to be repaired using tissue engineering strategies; however, it remains challenging to instruct cell differentiation within a scaffold to produce tissue with appropriate structural, chemical and mechanical properties. We aimed to address this by driving progenitor cells to adopt a chondrogenic phenotype through the tailoring of scaffold composition and physical properties. Monomeric type-I and type-II collagen scaffolds, which avoid potential immunogenicity associated with fibrillar collagens, were fabricated with and without chondroitin sulfate (CS) and their ability to stimulate the chondrogenic differentiation of human bone marrow-derived mesenchymal stem cells was assessed. Immunohistochemical analyses showed that cells produced abundant collagen type-II on type-II scaffolds and collagen type-I on type-I scaffolds. Gene expression analyses indicated that the addition of CS - which was released from scaffolds quickly - significantly upregulated expression of type II collagen, compared to type-I and pure type-II scaffolds. We conclude that collagen type-II and CS can be used to promote a more chondrogenic phenotype in the absence of growth factors, potentially providing an eventual therapy to prevent OA.

[Appropriate use of psychotropic drugs in institutionalized elderly presenting acute confusional state (delirium)]. / Usage adéquat des psychotropes chez les personnes âgées institutionnalisées en cas d'état confusionnel aigu (delirium).

Delirium (acute confusion) is a common, morbid, and costly geriatric syndrome that affects onethird of hospitalized older adults. As evidence mounts that delirium may persist for weeks to months, concern about delirium can no longer be restricted to acute hospitals. We present a review about non-pharmacologic and pharmacologic management of delirium in institution.

Le " Delirium " (état confusionnel) est un syndrome gériatrique fréquent et coûteux qui affecte un tiers des personnes âgées hospitalisées ; sa prévalence en institution est mal connue. Il apparaît que ce syndrome peut persister pendant des semaines à des mois, et n'est donc pas limité aux hospitalisations aiguës. Nous présentons une revue de la littérature sur la prise en charge du delirium en institution suivie d'une proposition d'algorithme définissant l'approche pharmacologique et non pharmacologique de ce syndrome gériatrique.

Isolation of aspalathin and nothofagin from rooibos (Aspalathus linearis) using high-performance countercurrent chromatography: sample loading and compound stability considerations.

Aspalathin and nothofagin, the major dihydrochalcones in rooibos (Aspalathus linearis), are valuable bioactive compounds, but their bioactivity has not been fully elucidated. Isolation of these compounds using high-performance countercurrent chromatography (HPCCC), a gentle, support-free, up-scalable technique, offers an alternative to synthesis for obtaining sufficient amounts. An HPLC-DAD method was adapted to allow rapid (16 min from injection to injection) quantification of the four major compounds (aspalathin, nothofagin, isoorientin, orientin) during development of the isolation protocol. The traditional shake-flask method, used to determine distribution constants (K(D)) for target compounds, was also adapted to obtain higher repeatability. Green rooibos leaves with a high aspalathin and nothofagin content were selected as source material. Sample loading of the polyphenol-enriched extract was limited due to constituents with emulsifying properties, but could be increased by removing ethanol-insoluble matter. Furthermore, problems with degradation of aspalathin during HPCCC separation and further processing could be limited by acidifying the HPCCC solvent system. Aspalathin was shown to be fairly stable at pH 3 (91% remaining after 29 h) compared to pH 7 (45% remaining after 29 h). Aspalathin and nothofagin with high purities (99% and 100%, respectively) were obtained from HPCCC fractions after semi-preparative HPLC.

Inflaming the diseased brain: a role for tainted melanins.

Inflammation plays a crucial role in neurodegenerative diseases, but the irritants responsible for this response remain largely unknown. This report addressed the hypothesis that hypochlorous acid reacts with dopamine to produce melanic precipitates that promote cerebral inflammation. Spectrophotometric studies demonstrated that nM amounts of HOCl and dopamine react within seconds. A second-order rate constant for the reaction of HOCl and dopamine of 2.5 × 10(4)M(-1)s(-1) was obtained by measuring loss of dopaminergic fluorescence due to HOCl. Gravimetric measurements, electron microscopy, elemental analysis, and a novel use of flow cytometry confirmed that the major product of this reaction is a precipitate with an average diameter of 1.5 µm. Flow cytometry was also used to demonstrate the preferential reaction of HOCl with dopamine rather than albumin. Engulfment of the chlorodopamine particulates by phagocytes in vitro caused these cells to release TNFα and die. Intrastriatal administration of 10(6) particles also increased the content of TNFα in the brain and led to a 50% loss of the dopaminergic neurons in the nigra. These studies indicate that HOCl and dopamine react quickly and preferentially with each other to produce particles that promote inflammation and neuronal death in the brain.

Benzophenone C- and O-glucosides from Cyclopia genistoides (Honeybush) inhibit mammalian α-glucosidase.

An enriched fraction of an aqueous extract prepared from the aerial parts of Cyclopia genistoides Vent. yielded a new benzophenone di-C,O-glucoside, 3-C-ß-d-glucopyranosyl-4-O-ß-d-glucopyranosyliriflophenone (1), together with small quantities of a known benzophenone C-glucoside, 3-C-ß-d-glucopyranosylmaclurin (2). The isolated compounds showed α-glucosidase inhibitory activity against an enzyme mixture extracted from rat intestinal acetone powder. Compound 2 exhibited significantly (p < 0.05) higher inhibitory activity (54%) than 1 (43%) at 200 µM. In vitro tests in several cell models showed that 1 and its 3-C-monoglucosylated derivative (3-C-ß-d-glucopyranosyliriflophenone) were marginally effective (p ≥ 0.05) in increasing glucose uptake.

Characterisation of freeze-dried type II collagen and chondroitin sulfate scaffolds.

Collagen type-II is the dominant type of collagen in articular cartilage and chondroitin sulfate is one of the main components of cartilage extracellular matrix. Afibrillar and fibrillar type-II atelocollagen scaffolds with and without chondroitin sulfate were prepared using casting and freeze-drying methods. The scaffolds were characterised to highlight the effects of fibrillogenesis and chondroitin sulfate addition on viscosity, pore structure, porosity and mechanical properties. Microstructure analysis showed that fibrillogenesis increased the circularity of pores significantly in collagen-only scaffolds, whereas with it, no significant change was observed in chondroitin sulfate-containing scaffolds. Addition of chondroitin sulfate to afibrillar scaffolds increased the circularity of the pores and the proportion of pores between 50 and 300 µm suitable for chondrocytes growth. Fourier transform infrared spectroscopy explained the bonding between chondroitin sulfate and afibrillar collagen- confirmed with rheology results- which increased the compressive modulus 10-fold to 0.28 kPa. No bonding was observed in other scaffolds and consequently no significant changes in compressive modulus were detected.

35Cl/37Cl isotope effects in 103Rh NMR of [RhCl(n)(H2O)(6-n)](3-n) complex anions in hydrochloric acid solution as a unique 'NMR finger-print' for unambiguous speciation.

A detailed analysis of the (35)Cl/(37)Cl isotope effects observed in the 19.11 MHz (103)Rh NMR resonances of [RhCl(n)(H(2)O)(6-n)](3-n) complexes (n=3-6) in acidic solution at 292.1K, shows that the 'fine structure' of each (103)Rh resonance can be understood in terms of the unique isotopologue and in certain instances the isotopomer distribution in each complex. These (35)Cl/(37)Cl isotope effects in the (103)Rh NMR resonance of the [Rh(35/37)Cl(6)](3-) species manifest only as a result of the statistically expected (35)Cl/(37)Cl isotopologues, whereas for the aquated species such as for example [Rh(35/37)Cl(5)(H(2)O)](2-), cis-[Rh(35/37)Cl(4)(H(2)O)(2)](-) as well as the mer-[Rh(35/37)Cl(3)(H(2)O)(3)] complexes, additional fine-structure due to the various possible isotopomers within each class of isotopologues, is visible. Of interest is the possibility of the direct identification of stereoisomers cis-[RhCl(4)(H(2)O)(2)](-), trans-[RhCl(4)(H(2)O)(2)](-), fac-[RhCl(3)(H(2)O)(3)] and mer-[RhCl(3)(H(2)O)(3)] based on the (103)Rh NMR line shape, other than on the basis of their very similar δ((103)Rh) chemical shift. The (103)Rh NMR resonance structure thus serves as a novel and unique 'NMR-fingerprint' leading to the unambiguous assignment of [RhCl(n)(H(2)O)(6-n)](3-n) complexes (n=3-6), without reliance on accurate δ((103)Rh) chemical shifts.

A shift in the collagen V antigenic epitope leads to T helper phenotype switch and immune response to self-antigen leading to chronic lung allograft rejection.

Immune responses to human leucocyte antigen (HLA) and self-antigen collagen V (Col-V) have been proposed in the pathogenesis of chronic rejection (bronchiolitis obliterans syndrome, BOS) following human lung transplantation (LTx). In this study, we defined the role for the shift in immunodominant epitopes of Col-V in inducing T helper phenotype switch leading to immunity to Col-V and BOS. Sera and lavage from BOS(+) LTx recipients with antibodies to Col-V were analysed. Two years prior to BOS, patients developed antibodies to both Col-V,α1(V) and α2(V) chains. However, at clinical diagnosis of BOS, antibodies became restricted to α1(V). Further, lung biopsy from BOS(+) patients bound to antibodies to α1(V), indicating that these epitopes are exposed. Fourteen Col-V peptides [pep1-14, pep1-4 specific to α1(V), pep5-8 to α1,2(V) and pep9-14 to α2(V)] which bind to HLA-DR4 and -DR7, demonstrated that prior to BOS, pep 6, 7, 9, 11 and 14 were immunodominant and induced interleukin (IL)-10. However, at BOS, the response switched to pep1, 4 and 5 and induced interferon (IFN)-γ and IL-17 responses, but not IL-10. The T helper (Th) phenotype switch is accompanied by decreased frequency of regulatory T cells (T(regs) ) in the lavage. LTx recipients with antibodies to α1(V) also demonstrated increased matrix metalloproteinase (MMP) activation with decreased MMP inhibitor, tissue inhibitor of metalloproteinase (TIMP), suggesting that MMP activation may play a role in the exposure of new Col-V antigenic epitopes. We conclude that a shift in immunodominance of self-antigenic determinants of Col-V results in induction of IFN-γ and IL-17 with loss of tolerance leading to autoimmunity to Col-V, which leads to chronic lung allograft rejection.

Validated intraclass correlation statistics to test item performance models.

A new method, with an application program in Matlab code, is proposed for testing item performance models on empirical databases. This method uses data intraclass correlation statistics as expected correlations to which one compares simple functions of correlations between model predictions and observed item performance. The method rests on a data population model whose validity for the considered data is suitably tested and has been verified for three behavioural measure databases. Contrarily to usual model selection criteria, this method provides an effective way of testing under-fitting and over-fitting, answering the usually neglected question "does this model suitably account for these data?"

Use of countercurrent chromatography during isolation of 6-hydroxyluteolin-7-O-ß-glucoside, a major antioxidant of Athrixia phylicoides.

Athrixia phylicoides, an indigenous South African herbal tea, has potential as a source of nutraceutical antioxidant extracts. Countercurrent chromatography (CCC) was employed as part of a multi-step process to isolate one of the major antioxidant compounds in A. phylicoides extracts. Antioxidant activity of the extracts was comparable to commercial nutraceutical extracts from Aspalathus linearis and Cyclopia spp. in a range of assays. The extracts were tested for radical scavenging (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) di-ammonium radical cation (ABTS·âº) scavenging, 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) scavenging and oxygen radical absorbance capacity (ORAC)), ferric reducing antioxidant potential (FRAP) and iron chelating activity, as well as inhibition of microsomal lipid and linoleic acid emulsion oxidation. After extraction optimisation, the antioxidant activity of the major phenolic compounds in an A. phylicoides extract was determined using the on-line HPLC-diode-array-DPPH and -ABTS·âº radical scavenging assays. Major compounds reported for the first time included chlorogenic acid, 1,3-dicaffeoylquinic acid, several hydroxycinnamic acid derivatives, including dicaffeoyl quinic acids, and an unidentified flavone-hexose. Finally, CCC was used in conjunction with liquid-liquid partitioning and semi-preparative reversed-phase HPLC to isolate 6-hydroxyluteolin-7-O-ß-glucoside (a major antioxidant) and quercetagetin-7-O-ß-glucoside (a minor compound present in CCC fraction containing 6-hydroxyluteolin-7-O-ß-glucoside) from an A. phylicoides extract. The chemical structures of the isolated compounds were confirmed by LC high-resolution electrospray ionisation MS, as well as ¹H, ¹³C and 2D NMR spectroscopy. This is the first report of the isolation of these compounds from A. phylicoides.