Transfusion in critical care - a UK regional audit of current practice.

A consistent message within critical care publications has been that a restrictive transfusion strategy is non-inferior, and possibly superior, to a liberal strategy for stable, non-bleeding critically ill patients. Translation into clinical practice has, however, been slow. Here, we describe the degree of adherence to UK best practice guidelines in a regional network of nine intensive care units within Wessex. All transfusions given during a 2-month period were included (n = 444). Those given for active bleeding or within 24 h of major surgery, trauma or gastrointestinal bleeding were excluded (n = 148). The median (IQR [range]) haemoglobin concentration before transfusion was 73 (68-77 [53-106]) g.l-1 , with only 34% of transfusion episodes using a transfusion threshold of < 70 g.l-1 . In a subgroup analysis that did not study patients with a history of cardiac disease (n = 42), haemoglobin concentration before transfusion was 72 (68-77 [50-98]) g.l-1 , with only 36% of transfusion episodes using a threshold of < 70 g.l-1 (see Fig. 3). Most blood transfusions given to critically ill patients who were not bleeding in this audit used a haemoglobin threshold > 70 g.l-1 . The reason why recommendations on transfusion triggers have not translated into clinical practice is unclear. With a clear national drive to decrease usage of blood products and clear evidence that a threshold of 70 g.l-1 is non-inferior, it is surprising that a scarce and potentially dangerous resource is still being overused within critical care. Simple solutions such as electronic patient records that force pause for thought before blood transfusion, or prescriptions that only allow administration of a single unit in non-emergency circumstances may help to reduce the incidence of unnecessary blood transfusions.

Energy partition in magnetic reconnection in Earth's magnetotail.

The partition of energy flux in magnetic reconnection is examined experimentally using Cluster satellite observations of collisionless reconnection in Earth's magnetotail. In this plasma regime, the dominant component of the energy flux is ion enthalpy flux, with smaller contributions from the electron enthalpy and heat flux and the ion kinetic energy flux. However, the Poynting flux is not negligible, and in certain parts of the ion diffusion region the Poynting flux in fact dominates. Evidence for earthward-tailward asymmetry is ascribed to the presence of Earth's dipole fields.

Extended magnetic reconnection across the dayside magnetopause.

The extent of where magnetic reconnection (MR), the dominant process responsible for energy and plasma transport into the magnetosphere, operates across Earth's dayside magnetopause has previously been only indirectly shown by observations. We report the first direct evidence of X-line structure resulting from the operation of MR at each of two widely separated locations along the tilted, subsolar line of maximum current on Earth's magnetopause, confirming the operation of MR at two or more sites across the extended region where MR is expected to occur. The evidence results from in-situ observations of the associated ion and electron plasma distributions, present within each magnetic X-line structure, taken by two spacecraft passing through the active MR regions simultaneously.

Modelling 2,4-dichlorophenol bioavailability and bioaccumulation by the freshwater fingernail clam Sphaerium corneum using artificial particles and humic acids.

The complex and variable composition of natural sediments makes it very difficult to predict the bioavailability and bioaccumulation of sediment-bound contaminants. Several approaches have been proposed to overcome this problem, including an experimental model using artificial particles with or without humic acids as a source of organic matter. For this work, we have applied this experimental model, and also a sample of a natural sediment, to investigate the uptake and bioaccumulation of 2,4-dichlorophenol (2,4-DCP) by Sphaerium corneum. Additionally, the particle-water partition coefficients (K(d)) were calculated. The results showed that the bioaccumulation of 2,4-DCP by clams did not depend solely on the levels of chemical dissolved, but also on the amount sorbed onto the particles and the characteristics and the strength of that binding. This study confirms the value of using artificial particles as a suitable experimental model for assessing the fate of sediment-bound contaminants.

The Rosetta mission orbiter science overview: the comet phase.

The international Rosetta mission was launched in 2004 and consists of the orbiter spacecraft Rosetta and the lander Philae. The aim of the mission is to map the comet 67P/Churyumov-Gerasimenko by remote sensing, and to examine its environment in situ and its evolution in the inner Solar System. Rosetta was the first spacecraft to rendezvous with and orbit a comet, accompanying it as it passes through the inner Solar System, and to deploy a lander, Philae, and perform in situ science on the comet's surface. The primary goals of the mission were to: characterize the comet's nucleus; examine the chemical, mineralogical and isotopic composition of volatiles and refractories; examine the physical properties and interrelation of volatiles and refractories in a cometary nucleus; study the development of cometary activity and the processes in the surface layer of the nucleus and in the coma; detail the origin of comets, the relationship between cometary and interstellar material and the implications for the origin of the Solar System; and characterize asteroids 2867 Steins and 21 Lutetia. This paper presents a summary of mission operations and science, focusing on the Rosetta orbiter component of the mission during its comet phase, from early 2014 up to September 2016.This article is part of the themed issue 'Cometary science after Rosetta'.

The conformations of nitroxide-labelled fatty acid probes of membrane structure as studied by 2H-NMR.

The electron spin resonance (ESR) spectrum of a nitroxide spin probe intercalated in a membrane is influenced by the amplitude of anisotropic motion of the nitroxide group and by the geometry of the oxazolidine ring of the nitroxide. In the analysis of the ESR spectra of nitroxide-labelled fatty acid probes, it is generally assumed that the five-membered oxazolidine ring system is oriented rigidly perpendicular to the long molecular axis of the probe. This assumption is tested in the present study, using 2H-NMR of specifically deuterium-labelled nitroxide spin probes. Evidence is presented that the nitroxide does not display the assumed geometry in membranes. The departure from this geometry depends on the position of the nitroxide label on the acyl chain, with a more pronounced departure for position 5 relative to position 12. These and previous data provide an explanation for the discrepancies between spin-probe ESR and 2H-NMR order parameters in membranes.

Kinetic epitope mapping of the chicken lysozyme.HyHEL-10 Fab complex: delineation of docking trajectories.

The rate constants, k(on), for the formation of hen (chicken) lysozyme (HEWL). Fab-10 complexes have been determined for wild-type (WT) and epitope-mutated lysozymes by a homogeneous solution method based on the 95% reduced enzymatic activity of the complex. The values fall within a narrow 10-fold range [(0.18 to 1.92) x 10(6) M(-1)s(-l)]. The affinity constants, K(D), cover a broader, 440-fold, range from 0.075 to 33 nM. Values of K(D) as high as 7 microM were obtained for the complexes prepared from some mutations at HEWL positions 96 and 97, but the associated kinetic constants could not be determined. The values of k(on) are negatively correlated with side-chain volume at position 101HEWL, but are essentially independent of this parameter for position 21HEWL substitutions. The multiple mutations made at positions 21HEWL and 101HEWL provide sufficient experimental data on complex formation to evaluate phi values [phi = (deltadeltaGon)/(deltadeltaG(D))] at these two positions to begin to define trajectories for protein-protein association. The data, when interpreted within the concept of a two-step association sequence embracing a metastable encounter complex intermediate, argue that the rate determining step at position 21HEWL (phiavg = 0.2) is encounter complex formation, but the larger phi(avg) value of 0.36 experienced for most position 101HEWL mutations indicates a larger contribution from the post-encounter annealing process at this site for these replacements.

Quantitative evaluation of the chicken lysozyme epitope in the HyHEL-10 Fab complex: free energies and kinetics.

The hen (chicken) egg-white lysozyme (HEWL) epitope for the monoclonal antibody HyHEL-10 Fab (Fab-10) was investigated by alanine scan mutagenesis. The association rate constants (k(on)) for the HEWL Fab-10 complexes were obtained from the homogenous solution method described in the preceding paper (Taylor et al., 1998). A new method for determining the dissociation rate constant (k(off)) for the complex, by trapping nascent free antibody with an inactive HEWL mutant is described. The values of k(on) fall within a factor of 2 of the wild-type (WT) HEWL value (1.43+/-0.13 X 10(6)M(-1)s(-1)), while the increases in k(off)more nearly reflect the total change in free energies of the complex (deltadeltaG(D)). The dissociation constants (K(D)) were measured directly in those cases where satisfactory kinetic data could not be obtained. The Y20A, K96A, and K97A HEWL.Fab-10 complexes are destabilized by more than 4 kcal/mol compared to the WT complex. The R21A, L75A, and D101A antibody complexes are moderately destabilized (0.7 < deltadeltaG(D)< or = 1.0 kcal/mol). Additional mutations of the "hotspot" residues (Tyr20, Lys96, Lys97) were constructed to probe, more precisely, the nature of their contributions to complex formation. The results show that the entire hydrocarbon side chains of Tyr20 and Lys97, and only the epsilon-amino group of Lys96, contribute to the stability of the complex. The value of deltadeltaG(D) for the R21A mutant complex is a distinct outlier in the Arg21 replacement series demonstrating the importance of supplementing alanine scan mutagenesis with additional mutations.

Molecular cloning and characterization of a novel Schistosoma japonicum "irradiated vaccine-specific" antigen, Sj14-3-3.

A Schistosoma japonicum cDNA coding for a full length S. japonicum 14-3-3 protein was obtained by antibody screening of an adult worm cDNA library using sera taken from mice vaccinated with UV-attenuated cercariae, which are capable of transferring high levels of passive immunity to this parasite. The deduced amino acid sequence consists of 254 amino acids and is highly homologous with 14-3-3 family of proteins from a variety of species (55-69% identity). The recombinant S. japonicun 14-3-3 protein (rSj14-3-3) was expressed and purified in pGEX/E. coli, and in Western blotting was strongly recognised by sera from mice, rats and bovines vaccinated with irradiated S. japonicum cercariae. Analysis of mRNA showed that Sj14-3-3 is expressed in sporocysts and adult worms, but not in cercariae, however mouse antisera against rSj14-3-3 recognised a 29 kDa native antigen in antigen preparations made from eggs, cercariae, schistosomula and adult worms of S. japonicum indicating that this antigen is present in all life-cycle stages. The presence of the native antigen in detergent extracts of intact schistosomula suggests that it is also present in the schistosomular tegument which is the most vulnerable target for immune attack. However, antisera against rSj14-3-3 did not recognise a similar band in S. mansoni or S. haematobium antigens, indicating that, like the UV-attenuated vaccines, this protein induced species-specific immune responses. Southern blot analysis suggested that there may exist more than one gene copy and/or polymorphism for Sj14-3-3. Immunoelectron microscopy confirmed that the native antigen is present throughout the body of adult worms including the tegument, but is less abundant in the muscles. The potential of rSj14-3-3 as a vaccine is now under further investigation.

Inter-species variation of schistosome 28-kDa glutathione S-transferases.

The 28-kDa glutathione S-transferase from Schistosoma mansoni (Sm28GST) is a candidate vaccine antigen. To evaluate the antigenic and phylogenetic variations between the 28-kDa GSTs from 4 species of schistosome, we have cloned and sequenced the 28-kDa GSTs from Schistosoma haematobium (Sh28GST) and Schistosoma bovis (Sb28GST). Sb28GST and Sh28GST are more similar to each other (97%) than to Sm28GST (90%) and particularly to the 28-kDa GST from Schistosoma japonicum (Sj28GST, 77%). Antisera directed against the major Sm28GST epitopes revealed differences in the recognition of the 28-kDa GSTs from the other schistosome species suggesting that these regions have been subjected to evolutionary pressure. The consequences of such species-specific epitopes on the development of a multi-species anti-schistosome vaccine are discussed.

Cloning of Schistosoma japonicum 14-3-3 epsilon (Sj14-3-3 epsilon), a new member of the 14-3-3 family of proteins from schistosomes.

A new member of the 14-3-3 protein family from Schistosoma japonicum has been identified. Phylogenetic analysis showed that this member belongs to the epsilon subfamily of the 14-3-3 proteins, and it is therefore named Sj14-3-3 epsilon. Consistent with the findings for the previously reported S. japonicum 14-3-3 protein (Sj14-3-3), Southern analysis suggested the presence of more than one gene, and/or introns or allelic polymorphism in this epsilon isoform. By RT-PCR, Sj14-3-3 epsilon was shown to be stage-specifically transcribed, being abundant in adults, present in sporocysts but absent in cercariae. Furthermore, mRNA of the epsilon isoform seemed to be much less abundant in the sporocyst stage, compared with Sj14-3-3. This suggests varying requirements of the different 14-3-3 isoforms at different stages of the life cycle.

Effects of subanesthetic concentrations of enflurane on rat pregnancy and early development.

Anesthetic pollutants in the operating room have been implicated in producing spontaneous abortion in exposed personnel and congenital malformations among their offspring. To test the effects of trace concentrations of enflurane on pregnancy, rats were exposed to two levels (10.7 and 63.7 ppm) of the anesthetic for 8 hr daily from days 1 to 19 of pregnancy. Litter sizes were not affected but birth weights of exposed offspring were slightly higher than controls. During lactation, cross-fostering studies were performed. Exposed offspring were housed with nonexposed mothers and vice versa to determine if exposure during pregnancy affected early development. Weights at 7, 14, and 21 days of age did not differ among the offspring in the lower dose experiment. Weights of the cross-fostered groups in the high dose experiment were decreased at day seven compared to controls. In the same experiment, exposed offspring housed with exposed mothers were heavier than controls on day 21 of lactation. The modest nature of these alterations suggests that enflurane has little or no gross effect on rat pregnancy and postnatal development.

Observations on cattle schistosomiasis in the Sudan, a study in comparative medicine. IV. Preliminary observations on the mechanism of naturally acquired resistance.

Suppression of egg production is the main parasitological manifestation of naturally acquired resistance to Schistosoma bovis in Sudanese cattle. In preliminary investigations on the mechanisms involved, 700-4,000 "suppressed" adult worms were surgically transplanted from six "resistant" donor cattle with very low fecal egg counts (0-8 eggs/g, epg) into six normal recipients. After transplantation, large numbers of eggs were excreted in the feces of the recipient cattle, beginning at between 5 and 16 days after operation, and reaching counts of 55-405 epg at between 6 and 20 days post transplantation. In the cattle with the highest egg counts, egg counts soon fell sharply from peak levels, whereas in cattle with lower peak counts, more steady counts were maintained. All the recipients were perfused at days 46-56, when between 0.1% and 78.5% of the transplanted worms were recovered. In the second experiment, 1,000-ml quantities of pooled sera from "resistant" donors were injected intraperitoneally into each of four normal recipient calves, while another four were injected with pooled sera from uninfected cattle. All the calves were challenged percutaneously the next day with 7,500 cercariae each, and the course of infection was followed by parasitological and clinical measurements until perfusion 18 weeks later. The results showed that the "immune" sera had a negligible effect on the numbers of worms which developed, and had no significant effect on the fecal egg counts or clinical parameters studied. There was, however, some evidence from the tissue egg counts of a reduction in the fecundity of the worms in calves injected with "immune" sera.(ABSTRACT TRUNCATED AT 250 WORDS)

Observations on cattle schistosomiasis in the Sudan, a study in comparative medicine. II. Experimental demonstration of naturally acquired resistance to Schistosoma bovis.

Epizootiological observations on Schistosoma bovis in cattle at Kosti, Sudan, showed a significant fall in age-specific prevalence and intensity with age, based on fecal egg count. To test the possibility that this is due to acquired resistance, Kosti cattle and a control group of cattle of similiar breed and age from a nonenzootic area were experimentally challenged with 70,000 S. bovis cercariae. Clinical observations showed very clearly that the Kosti cattle were able to withstand almost completely the effects of the challenge, whereas the controls developed lethal infections. Resistance was further demonstrated by clear differences between the two groups in terms of their body weights, hematological measurements, histopathological and pathophysiological responses, and worm and egg counts. The data suggested that the main basis of the resistance was a suppression of egg production by the worms from the challenge, rather than absolute prevention of their maturation. There was also evidence of a suppression of the fecundity of worms in the naturally infected Kosti cattle.

Observations on cattle schistosomiasis in the Sudan, a study in comparative medicine. III. Field testing of an irradiated Schistosoma bovis vaccine.

Previous work has shown that cattle can acquire a strong resistance to Schistosoma bovis infection following repeated natural exposure. Partial resistance to a laboratory challenge with S. bovis has also been demonstrated in calves after immunization with an irradiated schistosomular or cercarial vaccine. The aim of the present study was to see whether this type of vaccine could protect calves under the very different conditions of natural exposure to S. bovis in the field. Thirty 6- to 9-month-old calves were each immunized with 10,000 irradiated S. bovis schistosomula by intramuscular injection and 8 weeks later were released into an enzootic area along with 30 unvaccinated animals. The calves were followed up for 10 months, during which period protection was evidenced by a lower mortality rate, a slower rate of acquisition of infection, and lower fecal egg counts in the vaccinated calves. Necropsy of the survivors showed 60--70% reductions in worm and tissue egg counts of the vaccinated calves as compared to those not vaccinated.

Observations on cattle schistosomiasis in the Sudan, a study in comparative medicine. I. Epizootiological observations on Schistosoma bovis in the White Nile Province.

A 2-year epizootiological study was carried out on Schistosoma bovis in cattle in an enzootic area of the Sudan. The prevalence of infection, as judged by the Pitchford fecal egg counting technique, was very high, approaching 90% in 1.5-year-old animals. There was, however, a lower prevalence in older cattle, and this trend was also seen with the fecal egg counts. This suggests that the cattle gradually acquire resistance to reinfection, particularly since there seems to be little age-related variation in the amount of water contact. Monthly incidence rates, estimated from fecal examinations of initially uninfected "tracer" calves showed a marked seasonal pattern, being much higher in the hot summer months, and snail infection rates showed a similar seasonal pattern. In addition, both the monthly incidence measurements and the snail infection rates showed that transmission was much heavier in 1976 than in 1977. Epizootics such as those recorded previously in this area presumably arise from exceptionally intense transmission years.

Observations on cattle schistosomiasis in the Sudan, a study in comparative medicine. V. The effect of praziquantel therapy on naturally acquired resistance to Schistosoma bovis.

Studies in the White Nile area of the Sudan have shown that Zebu cattle acquire a high degree of resistance to Schistosoma bovis as a result of repeated natural exposures without, however, being able to eliminate their populations of adult schistosomes, although these do show greatly suppressed fecundity. To test whether these adult worms are necessary for the maintenance of resistance we cured six "naturally resistant" cattle (TC group) with a double treatment of 25 mg/kg praziquantel and compared their response to a 70,000 cercariae challenge with groups of "naturally resistant" but untreated cattle (UC group) and with previously unexposed, challenged cattle (CC group). Challenge was carried out 7 weeks after the second dose of praziquantel. The results confirmed that untreated cattle are "naturally resistant" and also showed that resistance was not abrogated by cure of the naturally-acquired infections. Thus, fecal egg counts after challenge reached mean maxima of 2,432 eggs per gram (epg) in the CC, but only 5 epg and 28 epg in the TC and UC groups, respectively. Similarly, mean worm counts were 85% and 69% lower in the TC and UC groups, respectively, and mean tissue egg densities were reduced by 72-99%, and 56-80%. Histopathologically, the TC and UC groups were also far less affected than the CC. Effective praziquantel treatment does therefore not destroy naturally acquired resistance to S. bovis, and may benefit infected livestock even in the absence of transmission control. The situation in human schistosomiasis is less clear, but there are several epidemiological and experimental indications of a similar conclusion for S. mansoni.

Observations on cattle schistosomiasis in the Sudan, a study in comparative medicine. VI. Demonstration of resistance to Schistosoma bovis challenge after a single exposure to normal cercariae or to transplanted adult worms.

Calves were immunized with Schistosoma bovis by a single experimental exposure to 10,000 normal cercariae. Some of these calves were perfused 14 weeks later, and a part of their worm loads was surgically transplanted into groups of normal recipient calves: "WPR" group calves received 500 pairs of worms; "MR" group calves received between 650 and 1,000 male worms alone. All three groups were subsequently challenged 10 weeks after surgery with 20,000 cercariae, as were a previously unexposed group of controls ("CC"). Mean post-challenge fecal egg counts in the animals immunized with cercariae ("PC" group) rose to a maximum of only 60 eggs per gram (e.p.g.), compared to 376 e.p.g. in the CC, and maximum fecal egg counts in the WPR and MR groups were also somewhat lower than in the CC, at 152 and 250 e.p.g., respectively. In spite of the much lower fecal egg counts in the PC than in the CC group, calculated adult "challenge" worm recoveries were only reduced by 11%, but PC group tissue egg densities derived from the challenge were 78-100% lower than in the CC. The WPR and MR groups had 43% and 37%, respectively, fewer worms than the CC, and mean tissue egg densities were lower by 39-63% and 63-76%, respectively, though in most cases there were no statistically significant differences from the CC.(ABSTRACT TRUNCATED AT 250 WORDS)

Orthodontists' perceptions of the impact of phase 1 treatment for Class II malocclusion on phase 2 needs.

The most appropriate timing for the treatment of Class II malocclusions is controversial. Some clinicians advocate starting a first phase in the mixed dentition, followed by a phase 2 in the permanent dentition. Others see no clear advantage to that approach and recommend that the entire treatment be done in the late mixed or early permanent dentition. This study examines how orthodontists, blinded to treatment approach, perceive the impact of phase 1 treatment on phase 2 needs. The sample consisted of 242 Class II subjects, aged 10 to 15, who had completed phase 1 or observation in a randomized clinical trial (RCT). For each subject, video orthodontic records, a questionnaire, a fact sheet, and a cephalometric tracing were sent to five randomly selected reviewing orthodontists blinded to subject group and study purpose. Reviewing orthodontists were asked to assess treatment need, general approach, need for extractions, priority, difficulty, and determinants. Orthodontists agreed highly on treatment need (95%) and moderately on treatment approach (84%) and extraction need (80%). They did not perceive differences in need, approach, or extractions between treated and control groups. Treated subjects were judged as less difficult (p = 0.0001) and to have a lower treatment priority (p = 0.0001) than controls. In ranking problems that affect treatment decisions, the orthodontists ranked dental Class II (p = 0.005) and skeletal relationships (p = 0.004) more highly in control than in treated patients. These data indicate that orthodontists do not perceive phase 1 treatment for Class II as preventing the need for a second phase or as offering any particular advantage with respect to preventing the need for extractions or other skeletal treatments in that second phase. They do view early Class II treatment as an effective means of reducing the difficulty of and priority for phase 2.

Diagnosis of Schistosoma haematobium infection: evaluation of ELISA using keyhole limpet haemocyanin or soluble egg antigen in comparison with detection of eggs or haematuria.

Keyhole limpet haemocyanin (KLH) was compared with Schistosoma haematobium soluble egg antigen (SEA) in the enzyme-linked immunosorbent assay (ELISA) for detection of S. haematobium infection, using 187 human sera collected from the S. haematobium endemic area of Pemba Island, Tanzania, and 30 normal sera from blood donors in Europe. There was a clear separation in terms of immunoglobulin (Ig) G and IgM titres between parasitologically positive patients and the blood donors, but titres of many parasitologically negative individuals in the endemic area were significantly high in comparison with the normal controls. Using as cut-off point the mean optical density +2 SD of sera from the blood donors to define ELISA positivity, and comparing the results with urine egg counts, the sensitivity of IgG-ELISA using KLH or SEA was high (91.11% and 95.56%, respectively) but the specificity was poor (43.30% and 31.90%, respectively. Similar results were obtained with IgM. When the 'gold standard' of haematuria and/or egg positivity as indicative of infection was used, the sensitivity of the ELISAs was similar but the specificity was increased to 59.25% and 44.44%, respectively. These results suggest that the patients with haematuria were probably infected with S. haematobium, which further supported the diagnostic value of haematuria detection for S. haematobium infection in endemic areas, and KLH was found to have a potential use in immunodiagnosis of S. haematobium infection in endemic areas. With both KLH and SEA antigens, the trend of reactivity in ELISA provided a correlate of the egg output (parasite burden) of infected patients.