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Recent compelling evidence showed that innate immune effector cells could recognize allogeneic grafts and prime an adaptive immune response. Signal regulatory protein α (SIRPα) is an immunoglobulin superfamily receptor that is expressed on myeloid cells; the interaction between SIRPα and its ubiquitously expressed ligand CD47 elicits an inhibitory signal that suppresses macrophage phagocytic function. Additional studies showed that donor-recipient mismatch in SIRPα variants might activate monocytic allorecognition, possibly as the result of non-self SIRPα-CD47 interaction. However, the frequency of SIRPα variation and its role in hematopoietic stem cell transplantation (HSCT) remains unexplored. We studied 350 patients with acute myeloid leukemia/myelodysplastic syndrome who underwent HLA-matched related HSCT and found that SIRPα allelic mismatches were present in 39% of transplantation pairs. SIRPα variant mismatch was associated with a significantly higher rate of chronic graft-versus-host disease (GVHD; hazard ratio [HR], 1.5; P = .03), especially de novo chronic GVHD (HR, 2.0; P = .01), after adjusting for other predictors. Those with mismatched SIRPα had a lower relapse rate (HR, 0.6; P = .05) and significantly longer relapse-free survival (RFS; HR, 0.6; P = .04). Notably, the effect of SIRPα variant mismatch on relapse protection was most pronounced early after HSCT and in patients who were not in remission at HSCT (cumulative incidence, 73% vs 54%; HR, 0.5; P = .01). These findings show that SIRPα variant mismatch is associated with HSCT outcomes, possibly owing to innate allorecognition. SIRPα variant matching could provide valuable information for donor selection and risk stratification in HSCT. more...

Recent compelling evidence showed that innate immune effector cells could recognize allogeneic grafts and prime an adaptive immune response. Signal regulatory protein α (SIRPα) is an immunoglobulin superfamily receptor that is expressed on myeloid cells; the interaction between SIRPα and its ubiquitously expressed ligand CD47 elicits an inhibitory signal that suppresses macrophage phagocytic function. Additional studies showed that donor-recipient mismatch in SIRPα variants might activate monocytic allorecognition, possibly as the result of non-self SIRPα-CD47 interaction. However, the frequency of SIRPα variation and its role in hematopoietic stem cell transplantation (HSCT) remains unexplored. We studied 350 patients with acute myeloid leukemia/myelodysplastic syndrome who underwent HLA-matched related HSCT and found that SIRPα allelic mismatches were present in 39% of transplantation pairs. SIRPα variant mismatch was associated with a significantly higher rate of chronic graft-versus-host disease (GVHD; hazard ratio [HR], 1.5; P= .03), especially de novo chronic GVHD (HR, 2.0; P= .01), after adjusting for other predictors. Those with mismatched SIRPα had a lower relapse rate (HR, 0.6; P= .05) and significantly longer relapse-free survival (RFS; HR, 0.6; P= .04). Notably, the effect of SIRPα variant mismatch on relapse protection was most pronounced early after HSCT and in patients who were not in remission at HSCT (cumulative incidence, 73% vs 54%; HR, 0.5; P= .01). These findings show that SIRPα variant mismatch is associated with HSCT outcomes, possibly owing to innate allorecognition. SIRPα variant matching could provide valuable information for donor selection and risk stratification in HSCT. more...

Osmosensing transporter ProP detects the increase in cytoplasmic cation concentration associated with osmotically induced cell dehydration and mediates osmolyte uptake into bacteria. ProP is a 12-transmembrane helix protein with an α-helical, cytoplasmic C-terminal domain (CTD) linked to transmembrane helix XII (TM XII). It has been proposed that the CTD helix associates with the anionic membrane surface to lock ProP in an inactive conformation and that the release of the CTD may activate ProP. To investigate this possible activation mechanism, we have built and simulated a structural model in which the CTD was anchored to the membrane by TM XII and the CTD helix was associated with the membrane surface. Molecular dynamics simulations showed specific intrapeptide salt bridges forming when the CTD associated with the membrane. Experiments supported the presence of the salt bridge Lys447–Asp455 and suggested a role for these residues in osmosensing. Simulations performed at different salt concentrations showed weakened CTD–lipid interactions at 0.25 M KCl and gradual stiffening of the membrane with increasing salinity. These results suggest that salt cations may affect CTD release and activate ProP by increasing the order of membrane phospholipids. more...

Q I have been visiting my granddaughters' school for nine years, and saw this yesterday in the grounds, possibly for the first time! The plant we featured, Peltophorum pterocarpum, has the same common name of yellow poinciana due to its uncanny likeness to the true poinciana. Claire Kennedy from Sydney has won a six-month subscription for her letter about planting violas in her pot of tulips, so they could take over when the tulips died (above). The leaves of all 400 species in the Prunus genus contain cyanide, and are poisonous to livestock and domestic animals, causing nausea and vomiting if ingested. [Extracted from the article] more...

ProP is a member of the major facilitator superfamily, a proton-osmolyte symporter, and an osmosensing transporter. ProP proteins share extended cytoplasmic carboxyl terminal domains (CTDs) implicated in osmosensing. The CTDs of the best characterized, group A ProP orthologs, terminate in sequences that form intermolecular, antiparallel α-helical coiled coils (e.g., ProPEc, from Escherichia coli). Group B orthologs lack that feature (e.g., ProPXc, from Xanthomonas campestris). ProPXcwas expressed and characterized in E. colito further elucidate the role of the coiled coil in osmosensing. The activity of ProPXcwas a sigmoid function of the osmolality in cells and proteoliposomes. ProPEcand ProPXcattained similar activities at the same expression level in E. coli. ProPEctransports proline and glycine betaine with comparable high affinities at low osmolality. In contrast, proline weakly inhibited high-affinity glycine-betaine uptake via ProPXc.The KMfor proline uptake via ProPEcincreases dramatically with the osmolality. The KMfor glycine-betaine uptake via ProPXcdid not. Thus, ProPXcis an osmosensing transporter, and the C-terminal coiled coil is not essential for osmosensing. The role of CTD-membrane interaction in osmosensing was examined further. As for ProPEc, the ProPXcCTD co-sedimented with liposomes comprising E. coliphospholipid. Molecular dynamics simulations illustrated association of the monomeric ProPEcCTD with the membrane surface. Comparison with the available NMR structure for the homodimeric coiled coil formed by the ProPEc-CTD suggested that membrane association and homodimeric coiled-coil formation by that peptide are mutually exclusive. The membrane fluidity in liposomes comprising E. coliphospholipid decreased with increasing osmolality in the range relevant for ProP activation. These data support the proposal that ProP activates as cellular dehydration increases cytoplasmic cation concentration, releasing the CTD from the membrane surface. For group A orthologs, this also favors α-helical coiled-coil formation that stabilizes the transporter in an active form. more...

Objective:The aim of this study was to evaluate the economic and quality outcomes associated with a collaborative advanced practice nurse and hospitalist physician model of care on the inpatient stroke unit as compared with usual hospitalist physician-led care. Background:High functioning collaborative teams are anticipated to be essential under value-based reimbursement. Methods:Hospitalist nurse practitioners were assigned to the stroke unit in collaboration with hospitalist physicians to implement daily hospital management for patients with stroke and transient ischemic attack. To evaluate outcomes associated with the care model, a retrospective cross-sectional design was used with 100 patients in the collaborative advanced practice nurse and hospitalist physician care group and 100 patients in the usual hospitalist physician-led care group. Primary outcome measures were length of stay, 30-day readmissions, stroke core measure documentation, and patient experiences of care. Analysis of demographic characteristics assured that the samples were similar. Results:The collaborative care group performed better on one of five stroke core quality measures and on two of three patient experiences of care measures. Mean length of stay and hospital readmissions were similar between groups. Five patients left the stroke unit against medical advice in the usual hospitalist physician-led care group, whereas there were no discharges against medical advice in the collaborative care group. Conclusion:Advanced practice nurse and hospitalist physician collaboration is a promising model for healthcare quality improvement during inpatient stroke care; results are likely generalizable to other adult medicine populations. more...

The NHS Plan(DoH 2000) states that the modern National Health Service (NHS) will be driven by a cycle of continuous quality improvement. This will enhance the efficiency, productivity and performance of the NHS. The aim of this article is to examine clinical supervision as a quality assurance initiative. To achieve this, clinical governance and lifelong learning will be evaluated within a theoretical framework with the focus on clinical supervision. more...

There is a growing trend within perioperative practice for nurses to undertake dual roles as both scrubbed nurse and surgeon's first assistant. In this article, Janet Wood suggests that nurses are allowing themselves to be pressured into attempting to carry out both roles simultaneously. She fears that this puts nurses at risk of failing to satisfy both their legal and moral duty of care to their patients, and advises how to deal with this situation. more...

Concentrative uptake of osmoprotectants via transporter ProP contributes to the rehydration of Escherichia colicells that encounter high osmolality media. A member of the major facilitator superfamily, ProP is activated by osmotic upshifts in whole bacteria, in cytoplasmic membrane vesicles and in proteoliposomes prepared with the purified protein. Soluble protein ProQ is also required for full osmotic activation of ProP in vivo. ProP is differentiated from structural and functional homologues by its osmotic activation and its C‐terminal extension, which is predicted to form an α‐helical coiled‐coil. A synthetic polypeptide corresponding to the C‐terminus of ProP (ProP‐p) formed a dimeric α‐helical coiled‐coil. A derivative of transporter ProP lacking 26 C‐terminal amino acids was expressed but inactive. A derivative harbouring amino acid changes K460I, Y467I and H495I (each at the core, coiled‐coil ‘a’ position) required a larger osmotic upshift for activation than did the wild type transporter. The same changes extended, stabilized and altered the oligomeric state of the coiled‐coil formed by ProP‐p. Amino acid change R488I (also at the ‘a’ position) further increased the magnitude of the osmotic upshift required to activate ProP, reduced the activity attained and rendered ProP activation transient. Unexpectedly, replacement R488I destabilized the coiled‐coil formed by ProP‐p. The activity and osmotic activation of ProP were even more strongly attenuated by helix‐destabilizing change I474P. These data demonstrate that the carboxyl terminal domain of ProP can form a homodimeric α‐helical coiled‐coil with unusual properties. They implicate the C‐terminal domain in the osmotic activation of ProP. Copyright © 2000 John Wiley & Sons, Ltd. more...

Concentrative uptake of osmoprotectants via transporter ProP contributes to the rehydration of Escherichia coli cells that encounter high osmolality media. A member of the major facilitator superfamily, ProP is activated by osmotic upshifts in whole bacteria, in cytoplasmic membrane vesicles and in proteoliposomes prepared with the purified protein. Soluble protein ProQ is also required for full osmotic activation of ProP in vivo. ProP is differentiated from structural and functional homologues by its osmotic activation and its C-terminal extension, which is predicted to form an α-helical coiled-coil. A synthetic polypeptide corresponding to the C-terminus of ProP (ProP-p) formed a dimeric α-helical coiled-coil. A derivative of transporter ProP lacking 26 C-terminal amino acids was expressed but inactive. A derivative harbouring amino acid changes K460I, Y467I and H495I (each at the core, coiled-coil ‘a’ position) required a larger osmotic upshift for activation than did the wild type transporter. The same changes extended, stabilized and altered the oligomeric state of the coiled-coil formed by ProP-p. Amino acid change R488I (also at the ‘a’ position) further increased the magnitude of the osmotic upshift required to activate ProP, reduced the activity attained and rendered ProP activation transient. Unexpectedly, replacement R488I destabilized the coiled-coil formed by ProP-p. The activity and osmotic activation of ProP were even more strongly attenuated by helix-destabilizing change I474P. These data demonstrate that the carboxyl terminal domain of ProP can form a homodimeric α-helical coiled-coil with unusual properties. They implicate the C-terminal domain in the osmotic activation of ProP. Copyright © 2000 John Wiley & Sons, Ltd. more...

Osmosensing transporter ProP forestalls cellular dehydration by detecting environments with high osmotic pressure and mediating the accumulation of organic osmolytes by bacterial cells. It is composed of 12 transmembrane helices with cytoplasmic N- and C-termini. In Escherichia coli, dimers form when the C-terminal domains of ProP molecules form homodimeric, antiparallel, α-helical coiled coils. No dominant negative effect was detected when inactive and active ProP molecules formed heterodimers in vivo. Purification of ProP in detergent dodecylmaltoside yielded monomers, which were functional after reconstitution in proteoliposomes. With other evidence, this suggests that ProP monomers function independently whether in the monomeric or dimeric state. Amino acid replacements that disrupted or reversed the coiled coil did not prevent in vivo dimerization of ProP detected with a bacterial two-hybrid system. Maleimide labeling detected no osmolality-dependent variation in the reactivities of cysteine residues introduced to transmembrane helix (TM) XII. In contrast, coarse-grained molecular dynamic simulations detected deformation of the lipid around TMs III and VI, on the lipid-exposed protein surface opposite to TM XII. This suggests that the dimer interface of ProP includes the surfaces of TMs III and VI, not of TM XII as previously suggested by crosslinking data. Homology modeling suggested that coiled-coil formation and dimerization via such an interface are not mutually exclusive. In previous work, alterations to the C-terminal coiled coil blocked co-localization of ProP with phospholipid cardiolipin at E. colicell poles. Thus, dimerization may contribute to ProP targeting, adjust its lipid environment, and hence indirectly modify its osmotic stress response. more...

This comparative study investigates the effect of user involvement in classroom work on mental health students' learning while undertaking the Diploma in Higher Education and Nursing programme. Recent policy recommendations suggest there should be user involvement in all aspects of the nursing curriculum. However, there appears to be a dearth of literature evaluating the outcomes of this on student learning. In this study, triangulation of methods was utilised; this consisted of classroom observation, student questionnaires and focus group discussion to evaluate the user involvement. A user-centred measurement tool was developed from earlier work that provided a measure on three dimensions: the use of terminology and jargon, empathetic understanding, and an individualised approach when identifying and responding to clients' needs. The outcomes indicated that students who were given an experience of user involvement in classroom work differed from those in the same cohort who had not been exposed to similar user input - they were less likely to rely on the use of professional terminology and jargon, more able to empathise with clients' distressing experiences, less likely to use defensive 'distancing' and more likely to take an individualised approach to assessment and intervention. This supported the intended aims of the project: that user involvement would enable students to take a more user-centred approach to mental health assessment. more...

In a previous paper we presented ultraviolet (leff=1550 A) high-speed photometry of the eclipsing dwarf nova Z Cha obtained near the peak of a normal eruption, and we derived a maximum-entropy disk map from the eclipse light curve. In the present paper we report a new calculation of the disk map and temperature profile. The calculation differs from the previous one--and all other calculations of disk maps--in two ways: first, we have used realistic model atmospheres to convert the surface brightness of the disk to effective temperature, and second, we have included the effects of limb darkening, which is large at ultraviolet wavelengths and strongly affects the inferred temperature and geometry of the disk. Inclusion of limb darkening in the models made the distribution of surface brightness with radius much steeper than the distribution derived without limb darkening, but the use of realistic model spectra instead of blackbody spectra to convert the surface brightness to temperature flattened the distribution again so that the net effect was to leave the temperature distribution nearly unchanged. The distribution remains much flatter than the r[?]3/4 law predicted for optically thick, steady-state disks. In agreement with our earlier results, we find that the disk in Z Cha becomes flared during eruptions. The derived flare angle is large, 6deg, but not as large as the flare needed for a disk with zero limb darkening. For comparison, model atmospheres for disks similar to the disk in Z Cha give photosphere heights corresponding to flare angles between 3deg and 4deg. more...

We present near-infrared, H-band (1.45-1.85 mm) observations of an eclipsing dwarf nova, IP Peg, in quiescence. The light curves are composed of ellipsoidal variations from the late-type secondary star and emission from the accretion disk and the bright spot. The light curves have two eclipses: a primary eclipse of the accretion disk and the bright spot by the companion star, and a secondary eclipse of the companion star by the disk. The ellipsoidal variations of the secondary star were modeled and subtracted from the data. The resulting light curve shows a pronounced double-hump variation. The double-hump profile resembles those seen in the light curves of WZ Sge and AL Com and likely originates in the accretion disk. The primary eclipse was modeled using maximum entropy disk mapping techniques. The accretion disk has a flat intensity distribution and a cool brightness temperature (Tbr [?] 3000 K) in the near-infrared. Superimposed on the face of the disk is the bright spot (Tbr [?] 10,000 K); the position of the bright spot is different from the observed range of visible bright spot positions. The near-infrared accretion disk flux is dominated by optically thin emission. The secondary eclipse indicates the presence of some occulting medium in the disk, but the eclipse depth is too shallow to be caused by a fully opaque accretion disk. more...

Summary Na+ and Li+ were found to stimulate the transport ofl-proline by cells ofEscherichia coli induced for proline utilization. The gene product of the put P gene is involved in the expression of this transport activity since the put P+ strains CSH 4 and WG 148 show activity and the put P− strain RM 2 fails to show this cation coupled transport. The addition of proline was found to stimulate the uptake of Li+ and of Na+. Attempts to demonstrate proline stimulated H+ uptake were unsuccessful. It is concluded that the proline carrier (coded by the put P gene) is responsible for Na+ (or Li+)-proline cotransport. more...

Transporters encoded in genetics loci putP, proP and proU mediate proline and/or betaine accumulation by Escherichia coli K-12. The ProP and ProU systems are osmoregulatory. Activation of ProP in response to hyperosmotic stress has been demonstrated both in vivo and in vitro. It therefore serves as a model experimental system for the analysis of osmosensory and osmoregulatory mechanisms. We developed methodologies which will facilitate the identification of proline transporter genes by functional complementation of putP proP proU bacteria. E. coli gene proP was isolated and located within a chromosomal DNA fragment. Deletion, complementation and sequence analysis revealed putative promoter and transcription termination signals flanking a 1500 base-pair open reading frame. The predicted 55 kDa ProP protein was hydrophobic. In vitro expression of proP yielded a protein whose apparent molecular mass was determined to be 42 kDa by polyacrylamide gel electrophoresis under denaturing conditions. Database searches and cluster analysis defined relationships among the ProP sequence and those of integral membrane proteins that comprise a transporter superfamily. Members of the superfamily catalyze facilitated diffusion or ion linked transport of organic solutes in prokaryotes and eukaryotes. Multiple alignment revealed particularly close correspondence among the ProP protein, citrate transporters from E. coli and Klebsiella pneumoniae and an α-ketoglutarate transporter from E. coli. The predicted ProP sequence differed from those closely similar sequences in possessing an extended central hydrophilic loop and a carboxyl terminal extension. Unlike other protein sequences within the transporter superfamily, the carboxyl terminal extension of ProP was strongly predicted to participate in formation of an α-helical coiled coil. These data suggest that the ProP protein catalyzes solute-ion cotransport. Its unusual structural features may be related to osmoregulation of its activity. Copyright 1993, 1999 Academic Press more...

The PutA protein of Escherichia colihas two enzymatic activities: proline dehydrogenase (PDH) and Δ1-pyrroline-5-carboxylate dehydrogenase (P5CDH). It associates with the cytoplasmic membrane as PDH and P5CDH and with putcontrol region DNA as putrepressor. Reduction of the PutA flavin by proline, a PutA conformational change and association of PutA with membranes are coincident. The nucleotide base sequence of E. coli putAwas determined, that of S. typhimurium putAwas updated and the deduced PutA protein sequences were surveyed for catalytic domains and ligand binding sites. The two sequences were very similar (80.5% and 95% on the nucleic acid and protein levels, respectively). Residues 650 through 1130 of PutA were very similar to the sequences of P5C dehydrogenases and aldehyde dehydrogenases from both prokaryotes and eukaryotes. Glutamate 883 and cysteine 917 of PutA were conserved with the corresponding residues in P5C dehydrogenases and with those proposed to be active site residues in the aldehyde dehydrogenases. Those relationships suggest that γ-glutamic semialdehyde, believed to equilibrate spontaneously with P5C, is the substrate for P5C dehydrogenases. Residues 340 through 590 of PutA were similar in sequence to proline dehydrogenases from Saccharomyces cerevisiaeand Drosophila melanogaster. Limited similarities were also found between residues 315 through 357 of PutA and a consensus sequence near a putative active site and FAD-binding region shared by succinate dehydrogenase sequences from several organisms. Since residues 228 through 358 of PutA were similar in sequence to several serine-pyruvate aminotransferases, PutA is proposed to catalyze the hydrolysis of P5C (a Schiff's base intermediate) to γ-glutamic semialdehyde. A carboxyl-terminal sequence that resembles a leucine zipper motif may be involved in association of PutA with putcontrol region DNA. more...

The Space Telescope with its UV and imaging capabilities will allow new methods of investigating cataclysmic variables to be used. It provides the first opportunity to obtain high time resolution UV observations of cataclysmic variables, both spectroscopically and photometrically. Phase resolved observations of eclipses can now be obtained which will allow the UV surface brightness distributions in accretion disks to be studied. Eclipses of white dwarfs that were not visible in optical light will be detected in some systems. Other variations such as dips (in dwarf novae, intermediate polars, and polars), flickering and oscillations can also be resolved for the first time in the UV. High spatial resolution, long slit spectroscopy and imaging with the FOC and WF/PC can be used to study the physical condition and morphology of ejected material around novae, recurrent novae and pre-cataclysmic variables. The UV and H-alpha imaging capabilities will also enable searches for cataclysmic variables in globular clusters to be carried out further into their cores than has been possible before. more...

We report on a 1 day ASCAobservation and ROSATHRI observations of the eclipsing dwarf nova HT Cas. The presence of the X-ray eclipse, originally detected in a ROSATPSPC observation, is confirmed at a much higher significance level. The quality of the ASCAlight curve is high enough to allow detailed investigation of the eclipse depth, width, and shape. The eclipse is found to be deep, compatible with being total. The eclipse width is comparable to that of the white dwarf, as derived from optical light curves, and in fact may be narrower. The eclipse transition is also found to be short, which puts a limit of 1.15 times the white dwarf radius as the total size of the X-ray emission region. The out-of-eclipse spectrum of HT Cas is found to be consistent with a single temperature (kT~ 10 keV), absorbed (NH~ 3.3 × 1021cm-2), thermal model. more...

This study examines the effectiveness of a training day for classroom learning assistants (LAs), which aims to change the way LAs interact with language-impaired children. The subjects were eight LAlanguage-impaired child dyads (with children aged 4:11 to 9:11 years) attending mainstream schools. The dyads were video recorded interacting at two times (before and after training) and in two contexts each time (sharing a book and in class). The training increased the percentage of facilitating utterances and recasts used by the LAs but did not decrease the percentage of controlling utterances used. Although the trained styles of interaction were used more frequently while sharing a book than in a classroom activity, the amount of change following training was not significantly different for these two settings. more...

The author reflects on the concept of botanical illustration in the advent of digital photography. She expresses her views on plant photography, including the challenges associated with it. She describes the satisfaction she achieves from painting. The author also cites the plants she included in an illustration she provided for the 50th anniversary of the Hardy Plant Society. more...

The article reviews the Paul Smith exhibition at the Design Museum in London, England.

A letter to the editor is presented in response to the article about cover pricing in the January 9, 2010 issue.