Structural biology of Rad50 ATPase: ATP-driven conformational control in DNA double-strand break repair and the ABC-ATPase superfamily

To clarify the key role of Rad50 in DNA double-strand break repair (DSBR), we biochemically and structurally characterized ATP-bound and ATP-free Rad50 catalytic domain (Rad50cd) from Pyrococcus furiosus. Rad50cd displays ATPase activity plus ATP-controlled dimerization and DNA binding activities. Rad50cd crystal structures identify probable protein and DNA interfaces and reveal an ABC-ATPase fold, linking Rad50 molecular mechanisms to ABC transporters, including P glycoprotein and cystic fibrosis transmembrane conductance regulator. Binding of ATP gamma-phosphates to conserved signature motifs in two opposing Rad50cd molecules promotes dimerization that likely couples ATP hydrolysis to dimer dissociation and DNA release. These results, validated by mutations, suggest unified molecular mechanisms for ATP-driven cooperativity and allosteric control of ABC-ATPases in DSBR, membrane transport, and chromosome condensation by SMC proteins.

Structural biochemistry and interaction architecture of the DNA double-strand break repair Mre11 nuclease and Rad50-ATPase

To clarify functions of the Mre11/Rad50 (MR) complex in DNA double-strand break repair, we report Pyrococcus furiosus Mre11 crystal structures, revealing a protein phosphatase-like, dimanganese binding domain capped by a unique domain controlling active site access. These structures unify Mre11's multiple nuclease activities in a single endo/exonuclease mechanism and reveal eukaryotic macromolecular interaction sites by mapping human and yeast Mre11 mutations. Furthermore, the structure of the P. furiosus Rad50 ABC-ATPase with its adjacent coiled-coil defines a compact Mre11/Rad50-ATPase complex and suggests that Rad50-ATP-driven conformational switching directly controls the Mre11 exonuclease. Electron microscopy, small angle X-ray scattering, and ultracentrifugation data of human and P. furiosus MR reveal a dual functional complex consisting of a (Mre11)2/(Rad50)2 heterotetrameric DNA processing head and a double coiled-coil linker.

The prevalence of metabolic syndrome in children: a systematic review of the literature

BACKGROUND

Metabolic syndrome has been identified as a condition of childhood relatively recently. The aim in this study was to describe the prevalence of metabolic syndrome in children allowing for differences in metabolic syndrome definitions.

METHODS

This was a systematic review of the OVID, EMBASE, and CINAHL databases, capturing details of overall prevalence and prevalence within groups categorized by obesity, gender, age, and ethnicity.

RESULTS

In all, 378 studies published since 2003 were identified, and of these 85 papers were included in the present review. When all studies were considered, the median prevalence of metabolic syndrome in whole populations was 3.3% (range 0%-19.2%), in overweight children was 11.9% (range 2.8%-29.3%), and in obese populations was 29.2% (range 10%-66%). Within-study analyses confirmed higher prevalence for obese compared to overweight (P=0.012) and obese compared to nonobese, nonoverweight children (P<0.001). Within-study analyses also revealed higher median metabolic syndrome prevalence for boys compared to girls (5.1% versus 3.0%, P<0.001) and also in older compared with younger children (5.6% versus 2.9%, P=0.001). Limited evidence was found to suggest differences between ethnic groups, and there were insufficient studies to determine whether metabolic syndrome prevalence was increasing over time.

CONCLUSIONS

This is the first systematic review of all of the relevant literature. It describes the magnitude of associations between metabolic syndrome and obesity, age, and gender. We find evidence that ethnicity and geography may be important to metabolic syndrome prevalence in children and these associations require further study.

Alpha-melanocyte-stimulating hormone protects against renal injury after ischemia in mice and rats

Reperfusion after ischemia induces cytokines, chemoattractant chemokines, adhesion molecules, and nitric oxide (NO). The resultant neutrophil adherence and NO potentiates renal injury. alpha-Melanocyte-stimulating hormone (alpha-MSH) is a potent anti-inflammatory agent that inhibits neutrophil migration and production of neutrophil chemokines and NO. Since neutrophils and NO promote renal ischemic injury, we sought to determine if alpha-MSH inhibits renal injury in a model of bilateral renal ischemia. alpha-MSH significantly reduced ischemia-induced renal damage, measured by changes in renal histology and plasma blood urea nitrogen and creatinine in mice. alpha-MSH significantly decreased tubule necrosis, neutrophil plugging, and capillary congestion. Delay of alpha-MSH treatment for 6 h after ischemia also significantly inhibited renal damage. alpha-MSH also significantly inhibited ischemic damage in rats. To begin to determine the mechanism of action of alpha-MSH, we measured its effects on mediators of neutrophil trafficking and induction of the inducible isoform of NO synthase-II. alpha-MSH inhibited ischemia-induced increases in mRNA for the murine neutrophil chemokine KC/IL-8. alpha-MSH also inhibited induction of mRNA for the adhesion molecule ICAM-1, which is known to be critical in renal ischemic injury. alpha-MSH inhibited nitration of kidney proteins and induction of NO synthase-II. We conclude: (a) alpha-MSH protects against renal ischemia/reperfusion injury; and (b) it may act, in part, by inhibiting the maladaptive activation of genes that cause neutrophil activation and adhesion, and induction of NO synthase.

Early growth characteristics and the risk of reduced lung function and asthma: A meta-analysis of 25,000 children

BACKGROUND

Children born preterm or with a small size for gestational age are at increased risk for childhood asthma.

OBJECTIVE

We sought to assess the hypothesis that these associations are explained by reduced airway patency.

METHODS

We used individual participant data of 24,938 children from 24 birth cohorts to examine and meta-analyze the associations of gestational age, size for gestational age, and infant weight gain with childhood lung function and asthma (age range, 3.9-19.1 years). Second, we explored whether these lung function outcomes mediated the associations of early growth characteristics with childhood asthma.

RESULTS

Children born with a younger gestational age had a lower FEV1, FEV1/forced vital capacity (FVC) ratio, and forced expiratory volume after exhaling 75% of vital capacity (FEF75), whereas those born with a smaller size for gestational age at birth had a lower FEV1 but higher FEV1/FVC ratio (P < .05). Greater infant weight gain was associated with higher FEV1 but lower FEV1/FVC ratio and FEF75 in childhood (P < .05). All associations were present across the full range and independent of other early-life growth characteristics. Preterm birth, low birth weight, and greater infant weight gain were associated with an increased risk of childhood asthma (pooled odds ratio, 1.34 [95% CI, 1.15-1.57], 1.32 [95% CI, 1.07-1.62], and 1.27 [95% CI, 1.21-1.34], respectively). Mediation analyses suggested that FEV1, FEV1/FVC ratio, and FEF75 might explain 7% (95% CI, 2% to 10%) to 45% (95% CI, 15% to 81%) of the associations between early growth characteristics and asthma.

CONCLUSIONS

Younger gestational age, smaller size for gestational age, and greater infant weight gain were across the full ranges associated with childhood lung function. These associations explain the risk of childhood asthma to a substantial extent.

Age and gender differences in physical capability levels from mid-life onwards: the harmonisation and meta-analysis of data from eight UK cohort studies

Using data from eight UK cohorts participating in the Healthy Ageing across the Life Course (HALCyon) research programme, with ages at physical capability assessment ranging from 50 to 90+ years, we harmonised data on objective measures of physical capability (i.e. grip strength, chair rising ability, walking speed, timed get up and go, and standing balance performance) and investigated the cross-sectional age and gender differences in these measures. Levels of physical capability were generally lower in study participants of older ages, and men performed better than women (for example, results from meta-analyses (N = 14,213 (5 studies)), found that men had 12.62 kg (11.34, 13.90) higher grip strength than women after adjustment for age and body size), although for walking speed, this gender difference was attenuated after adjustment for body size. There was also evidence that the gender difference in grip strength diminished with increasing age,whereas the gender difference in walking speed widened (p<0.01 for interactions between age and gender in both cases). This study highlights not only the presence of age and gender differences in objective measures of physical capability but provides a demonstration that harmonisation of data from several large cohort studies is possible. These harmonised data are now being used within HALCyon to understand the lifetime social and biological determinants of physical capability and its changes with age.

Childhood socioeconomic position and objectively measured physical capability levels in adulthood: a systematic review and meta-analysis

BACKGROUND

Grip strength, walking speed, chair rising and standing balance time are objective measures of physical capability that characterise current health and predict survival in older populations. Socioeconomic position (SEP) in childhood may influence the peak level of physical capability achieved in early adulthood, thereby affecting levels in later adulthood. We have undertaken a systematic review with meta-analyses to test the hypothesis that adverse childhood SEP is associated with lower levels of objectively measured physical capability in adulthood.

METHODS AND FINDINGS

Relevant studies published by May 2010 were identified through literature searches using EMBASE and MEDLINE. Unpublished results were obtained from study investigators. Results were provided by all study investigators in a standard format and pooled using random-effects meta-analyses. 19 studies were included in the review. Total sample sizes in meta-analyses ranged from N = 17,215 for chair rise time to N = 1,061,855 for grip strength. Although heterogeneity was detected, there was consistent evidence in age adjusted models that lower childhood SEP was associated with modest reductions in physical capability levels in adulthood: comparing the lowest with the highest childhood SEP there was a reduction in grip strength of 0.13 standard deviations (95% CI: 0.06, 0.21), a reduction in mean walking speed of 0.07 m/s (0.05, 0.10), an increase in mean chair rise time of 6% (4%, 8%) and an odds ratio of an inability to balance for 5s of 1.26 (1.02, 1.55). Adjustment for the potential mediating factors, adult SEP and body size attenuated associations greatly. However, despite this attenuation, for walking speed and chair rise time, there was still evidence of moderate associations.

CONCLUSIONS

Policies targeting socioeconomic inequalities in childhood may have additional benefits in promoting the maintenance of independence in later life.

Exploring the basis of peptide-carbohydrate crossreactivity: evidence for discrimination by peptides between closely related anti-carbohydrate antibodies

To investigate the molecular basis of antigenic mimicry by peptides, we studied a panel of closely related mAbs directed against the cell-wall polysaccharide of group A Streptococcus. These antibodies have restricted V-gene usage, indicating a shared mechanism of binding to a single epitope. Epitope mapping studies using synthetic fragments of the cell-wall polysaccharide supported this conclusion. All of the mAbs isolated crossreactive peptides from a panel of phage-displayed libraries, and competition studies indicated that many of the peptides bind at or near the carbohydrate binding site. Surprisingly, the peptides isolated by each mAb fell into distinct consensus-sequence groups that discriminated between the mAbs, and in general, the peptides bound only to the mAbs used for their isolation. Similar results were obtained with polyclonal antibodies directed against synthetic oligosaccharide fragments of the streptococcal cell-wall polysaccharide. Thus, the peptides appear to be specific for their isolating antibodies and are not recognized by the same mechanism as their carbohydrate counterparts.

The CD40/CD40 ligand interaction is required for resistance to toxoplasmic encephalitis

Since the CD40/CD40 ligand (CD40L) interaction is involved in the regulation of macrophage production of interleukin 12 (IL-12) and T-cell production of gamma interferon (IFN-gamma), effector cell functions associated with resistance to Toxoplasma gondii, the role of CD40L in immunity to this parasite was assessed. Infection of C57BL/6 mice with T. gondii results in an upregulation of CD40 expression on accessory cell populations at local sites of infection as well as in lymphoid tissues. Splenocytes from C57BL/6 mice infected with T. gondii for 5 days produced high levels of IL-12 and IFN-gamma when stimulated with toxoplasma lysate antigen, and blocking CD40L did not significantly alter the production of IFN-gamma or IL-12 by these cells. Similar results were observed with splenocytes and mononuclear cells isolated from the brains of chronically infected mice. Interestingly, although CD40L(-/-) mice infected with T. gondii produced less IL-12 than wild-type mice, they produced comparable levels of IFN-gamma but succumbed to toxoplasmic encephalitis 4 to 5 weeks after infection. The inability of CD40L(-/-) mice to control parasite replication in the brain correlated with the ability of soluble CD40L, in combination with IFN-gamma, to activate macrophages in vitro to control replication of T. gondii. Together, these results identify an important role for the CD40/CD40L interaction in resistance to T. gondii. However, this interaction may be more important in the control of parasite replication in the brain rather than the generation of protective T-cell responses during toxoplasmosis.

Identification of a role for NF-kappa B2 in the regulation of apoptosis and in maintenance of T cell-mediated immunity to Toxoplasma gondii

The NF-kappaB family of transcription factors are involved in the regulation of innate and adaptive immune functions associated with resistance to infection. To assess the role of NF-kappaB(2) in the regulation of cell-mediated immunity, mice deficient in the NF-kappaB(2) gene (NF-kappaB(2)(-/-)) were challenged with the intracellular parasite Toxoplasma gondii. Resistance to this opportunistic pathogen is dependent on the production of IL-12, which is required for the development of innate NK cell and adaptive T cell responses dominated by the production of IFN-gamma necessary to control replication of this parasite. Although wild-type controls were resistant to T. gondii, NF-kappaB(2)(-/-) mice developed severe toxoplasmic encephalitis and succumbed to disease between 3 and 10 wk following infection. However, NF-kappaB(2) was not required for the ability of macrophages to produce IL-12 or to inhibit parasite replication and during the acute stage of infection, NF-kappaB(2)(-/-) mice had no defect in their ability to produce IL-12 or IFN-gamma and infection-induced NK cell responses appeared normal. In contrast, during the chronic phase of the infection, susceptibility of NF-kappaB(2)(-/-) mice to toxoplasmic encephalitis was associated with a reduced capacity of their splenocytes to produce IFN-gamma associated with a loss of CD4(+) and CD8(+) T cells. This loss of T cells correlated with increased levels of apoptosis and with elevated expression of the pro-apoptotic molecule Fas by T cells from infected NF-kappaB(2)(-/-) mice. Together, these results suggest a role for NF-kappaB(2) in the regulation of lymphocyte apoptosis and a unique role for this transcription factor in maintenance of T cell responses required for long-term resistance to T. gondii.

The role of structure in antibody cross-reactivity between peptides and folded proteins

Peptides have the potential for targeting vaccines against pre-specified epitopes on folded proteins. When polyclonal antibodies against native proteins are used to screen peptide libraries, most of the peptides isolated align to linear epitopes on the proteins. The mechanism of cross-reactivity is unclear; both structural mimicry by the peptide and induced fit of the epitope may occur. The most effective peptide mimics of protein epitopes are likely to be those that best mimic both the chemistry and the structure of epitopes. Our goal in this work has been to establish a strategy for characterizing epitopes on a folded protein that are candidates for structural mimicry by peptides. We investigated the chemical and structural bases of peptide-protein cross-reactivity using phage-displayed peptide libraries in combination with computational structural analysis. Polyclonal antibodies against the well-characterized antigens, hen eggwhite lysozyme and worm myohemerythrin, were used to screen a panel of phage-displayed peptide libraries. Most of the selected peptide sequences aligned to linear epitopes on the corresponding protein; the critical binding sequence of each epitope was revealed from these alignments. The structures of the critical sequences as they occur in other non-homologous proteins were analyzed using the Sequery and Superpositional Structural Assignment computer programs. These allowed us to evaluate the extent of conformational preference inherent in each sequence independent of its protein context, and thus to predict the peptides most likely to have structural preferences that match their protein epitopes. Evidence for sequences having a clear structural bias emerged for several epitopes, and synthetic peptides representing three of these epitopes bound antibody with sub-micromolar affinities. The strong preference for a type II beta-turn predicted for one peptide was confirmed by NMR and circular dichroism analyses. Our strategy for identifying conformationally biased epitope sequences provides a new approach to the design of epitope-targeted, peptide-based vaccines.

Random peptide libraries

Over the past year, great strides have been made in the design of peptide libraries, and new approaches have been developed for identifying peptide ligands. The libraries comprise large collections of peptides, ranging from 1 million to 1 billion different sequences, which can be screened using monoclonal and polyclonal antibodies, receptors, enzymes or other target molecules. The power of this technology stems from the chemical diversity of the amino acids coupled with the large number of sequences in a library. As such, peptide libraries may be useful for finding ligands that can serve as leads for pharmaceutical development and other purposes.

First- and second-trimester fetal size and asthma outcomes at age 10 years

RATIONALE

Greater early fetal size is associated with reduced asthma risk and improved lung function in early childhood.

OBJECTIVES

To test the hypothesis that associations between early fetal size, asthma symptoms, and lung function persist into later childhood.

METHODS

In a longitudinal study, first- and second-trimester fetal measurements were recorded. At 10 years of age a respiratory questionnaire was completed. Spirometry, bronchial challenge, and skin-prick testing were undertaken in a subset.

MEASUREMENTS AND MAIN RESULTS

Fetal measurements were available in the first trimester for 853 individuals and the second trimester for 1,453. Questionnaires were returned for 927 children and 449 underwent detailed phenotyping. For each millimeter increase in first trimester size, asthma risk reduced by 6% (95% confidence interval[CI], 1–11) and FEV1 was higher by an average of 6 ml (95% CI, 1–11).First-trimester size was reduced in those with asthma at both 5 and 10 years compared with early or late onset wheeze (P , 0.02). Compared with persistent high growth in first and second trimesters,persistent low growth was associated with increased asthma risk(odds ratio, 2.8; 95% CI, 1.2–6.9) and a mean reduction in FEV1 of 103 ml (95% CI, 13–194), whereas increasing fetal size was associated with increased eczema risk (odds ratio, 2.5; 95% CI, 1.2–5.3).

CONCLUSIONS

Reduced fetal size from the first trimester is associated with increased risk for asthma and obstructed lung function in childhood. Relative change in size after the first trimester is associated with eczema.

Meals-on-wheels applicants are a population at risk for poor nutritional status

OBJECTIVE

To identify older adults with poor nutritional status among the independent-living elderly applying for meals-on-wheels, and to compare how a self-assessment tool and more traditional criteria identify nutritional risk.

DESIGN

Descriptive study.

SUBJECTS/SETTING

Meals-on-wheels applicants (n = 230 between 60 and 90 years of age (mean age = 77.4 +/- 7 years) who were free from terminal illness. Nutrition assessment data were collected in the home of each participant.

MAIN OUTCOME MEASURES

Risk assessment for poor nutritional status was determined using anthropometric, dietary, and laboratory data and with a Nutrition Screening Initiative (NSI) self-assessment tool-the "DETERMINE Your Nutritional Health" checklist.

STATISTICAL ANALYSES

Differences were assessed using Student's t test for unpaired data.

RESULTS

Seventy-four percent of study participants were found to be at risk for poor nutritional status according to the study criteria, and 98% were at risk for poor nutritional status according to the NSI self-assessment tool.

CONCLUSIONS

The majority of the applicants for meals-on-wheels were at risk for poor nutritional status. Thus, many independent-living older adults may need additional nutrition assessment and intervention to remain independent and in good nutritional status.

Dietetic guidelines on food and nutrition in the secondary prevention of cardiovascular disease ? evidence from systematic reviews of randomized controlled trials (second update, January 2006)

AIM

To update dietetic guidelines based on systematic review evidence on dietary advice to prevent further events in people with existing cardiovascular disease (CVD) (secondary prevention).

METHODS

The Cochrane Library, MEDLINE and EMBASE were comprehensively searched to January 2005 for systematic reviews on aspects of diet and heart health. Reviews were included if they searched systematically for randomized controlled trials relating to diet and secondary prevention of CVD. Each review was critically appraised by at least two members of the UK Heart Health and Thoracic Dietitians Group. The quality and results of each review were discussed and summarized at a group meeting.

RESULTS

Evidence-based strategies that reduce cardiovascular events in those with CVD include reduction in saturated fat and substitution with unsaturated fats. Individuals who have suffered a myocardial infarction may also benefit from adopting a Mediterranean type diet and increasing intake of omega 3 fats, but it is not clear whether they are beneficial for all patients with CVD. There is no systematic review evidence to support the use of antioxidant vitamins supplements, low glycaemic index diets, or homocysteine lowering therapies in this group.

CONCLUSION

There remains good evidence that reducing saturated fat reduces morbidity in patients with CVD. This advice is consistent for most manifestations of CVD, with the addition of Mediterranean dietary advice and increased omega 3 fats for those who have had a myocardial infarction.

Factors associated with symptoms of anxiety and depression in five cohorts of community-based older people: the HALCyon (Healthy Ageing across the Life Course) Programme

BACKGROUND

Symptoms of anxiety and depression are common in older people, but the relative importance of factors operating in early and later life in influencing risk is unclear, particularly in the case of anxiety.

METHOD

We used data from five cohorts in the Healthy Ageing across the Life Course (HALCyon) collaborative research programme: the Aberdeen Birth Cohort 1936, the Caerphilly Prospective Study, the Hertfordshire Ageing Study, the Hertfordshire Cohort Study and the Lothian Birth Cohort 1921. We used logistic regression to examine the relationship between factors from early and later life and risk of anxiety or depression, defined as scores of 8 or more on the subscales of the Hospital Anxiety and Depression Scale, and meta-analysis to obtain an overall estimate of the effect of each.

RESULTS

Greater neuroticism, poorer cognitive or physical function, greater disability and taking more medications were associated in cross-sectional analyses with an increased overall likelihood of anxiety or depression. Associations between lower social class, either in childhood or currently, history of heart disease, stroke or diabetes and increased risk of anxiety or depression were attenuated and no longer statistically significant after adjustment for potential confounding or mediating variables. There was no association between birth weight and anxiety or depression in later life.

CONCLUSIONS

Anxiety and depression in later life are both strongly linked to personality, cognitive and physical function, disability and state of health, measured concurrently. Possible mechanisms that might underlie these associations are discussed.

Early childhood wheezing symptoms in relation to plasma selenium in pregnant mothers and neonates

OBJECTIVE

Reduced dietary selenium intake has been linked to the development of asthma. We have investigated whether childhood wheezing symptoms, and asthma up to the age of 5 years are associated with plasma selenium and erythrocyte glutathione peroxidase (GPx) concentrations in pregnant mothers and neonates.

METHODS

Two thousand pregnant women were recruited and their 1924 singleton children followed up. Plasma selenium and erythrocyte GPx concentrations were measured in maternal blood during early pregnancy (12 weeks gestation) and in neonatal cord blood. Cohort children were followed up at 1, 2 and 5 years using a respiratory symptom questionnaire and at 5 years children were also invited for spirometry and skin-prick test (SPT). Maternal and neonatal plasma selenium and erythrocyte GPx were related to the childhood outcomes of wheezing, and asthma.

RESULTS

At 2 years 1282 children were followed up. At 5 years symptom data were available for 1167 children, 700 children were SPT tested, and forced expiratory volume in 1 s (FEV(1)) was measured in 478. Maternal plasma selenium concentration during early pregnancy was inversely associated with wheezing (odds ratio per 10 microg/kg plasma selenium 0.86, 95% confidence interval 0.76-0.97), and consulting a doctor because of wheeze (0.79, 0.69-0.93) in the second year of life. Cord plasma selenium was also inversely associated with wheezing (0.67, 0.47-0.96), and consulting a doctor because of wheeze (0.62, 0.41-0.93) in the second year of life. By age 5 these associations had disappeared. Maternal and neonatal erythrocyte GPx concentrations were not associated with any childhood outcomes at 2 or 5 years.

CONCLUSION

The selenium status of mothers during early pregnancy, and neonates is associated with early childhood wheezing but not asthma or atopic sensitization, furthermore, this association is absent by the age of 5 years.

Alpha-melanocyte-stimulating hormone inhibits renal injury in the absence of neutrophils

BACKGROUND

We previously showed that alpha-melanocyte stimulating hormone (alpha-MSH) decreases ischemia/reperfusion injury even when started six hours after ischemia. Alpha-MSH inhibits both neutrophil accumulation and nitric oxide production. To determine the relative importance of alpha-MSH on the neutrophil pathway, we examined the effects of alpha-MSH in injury models where neutrophil effects are minimal or absent.

METHODS

We studied the effects of alpha-MSH in (1) intercellular adhesion molecule-1 (ICAM-1) knock-out and background mice that were subjected to 40 minutes of ischemia and 24 hours reperfusion, and (2) isolated kidneys that were subjected to in vivo ischemia for 20 minutes and then perfused ex vivo for one hour without neutrophils. To begin to search for direct tubule effects of alpha-MSH, we studied the effect of alpha-MSH on nitric oxide (NO) in endotoxin/interferon-gamma-treated mouse cortical tubule cells.

RESULTS

ICAM-1 knock-out mice had 75% less neutrophil infiltration than background mice after ischemia. Despite the relative lack of neutrophils, alpha-MSH inhibited renal injury in ICAM-1 knock-out mice. Alpha-MSH also significantly preserved GFR and tubular sodium reabsorption in the isolated perfused ischemic kidney model. Alpha-MSH and a nitric oxide inhibitor did not exhibit synergy. Finally, alpha-MSH inhibited nitrite production by 20% in the mouse cortical tubule cells (MCT), similar to parallel observations in a cultured mouse macrophage line (RAW cells).

CONCLUSIONS

We conclude that alpha-MSH decreases renal injury when neutrophil effects are minimal or absent, indicating that alpha-MSH inhibits neutrophil-independent pathways of renal injury. The preservation of sodium absorption ex vivo and inhibition of nitrite production in cultured MCT cells suggests that alpha-MSH inhibits tubular injury by direct tubular effects.

The FEeding Support Team (FEST) randomised, controlled feasibility trial of proactive and reactive telephone support for breastfeeding women living in disadvantaged areas

OBJECTIVE

To assess the feasibility of implementing a dedicated feeding support team on a postnatal ward and pilot the potential effectiveness and cost-effectiveness of team (proactive) and woman-initiated (reactive) telephone support after discharge.

DESIGN

Randomised controlled trial embedded within a before-and-after study. Participatory approach and mixed-method process evaluation.

SETTING

A postnatal ward in Scotland.

SAMPLE

Women living in disadvantaged areas initiating breast feeding.

METHODS

Eligible women were recruited to a before-and-after intervention study, a proportion of whom were independently randomised after hospital discharge to intervention: daily proactive and reactive telephone calls for ≤14 days or control: reactive telephone calls ≤ day 14. Intention-to-treat analysis compared the randomised groups on cases with complete outcomes at follow-up.

PRIMARY OUTCOME

any breast feeding at 6-8 weeks assessed by a telephone call from a researcher blind to group allocation.

SECONDARY OUTCOMES

exclusive breast feeding, satisfaction with care, NHS costs and cost per additional woman breast feeding.

RESULTS

There was no difference in feeding outcomes for women initiating breast feeding before the intervention (n=413) and after (n=388). 69 women were randomised to telephone support: 35 intervention (32 complete cases) and 34 control (26 complete cases). 22 intervention women compared with 12 control women were giving their baby some breast milk (RR 1.49, 95% CI 0.92 to 2.40) and 17 intervention women compared with eight control women were exclusively breast feeding (RR 1.73, 95% CI 0.88 to 3.37) at 6-8 weeks after birth. The incremental cost of providing proactive calls was £87 per additional woman breast feeding and £91 per additional woman exclusively breast feeding at 6-8 weeks; costs were sensitive to service organisation.

CONCLUSIONS

Proactive telephone care delivered by a dedicated feeding team shows promise as a cost-effective intervention for improving breastfeeding outcomes. Integrating the FEeding Support Team (FEST) intervention into routine postnatal care was feasible.

TRIAL REGISTRATION NUMBER

ISRCTN27207603. The study protocol and final report are available on request.

Blockade of costimulation prevents infection-induced immunopathology in interleukin-10-deficient mice

Interleukin-10 (IL-10) is associated with inhibition of cell-mediated immunity and downregulation of the expression of costimulatory molecules required for T-cell activation. When IL-10-deficient (IL-10KO) mice are infected with Toxoplasma gondii, they succumb to a T-cell-mediated shock-like reaction characterized by the overproduction of IL-12 and gamma interferon (IFN-gamma) associated with widespread necrosis of the liver. Since costimulation is critical for T-cell activation, we investigated the role of the CD28-B7 and CD40-CD40 ligand (CD40L) interactions in this infection-induced immunopathology. Our studies show that infection of mice with T. gondii resulted in increased expression of B7 and CD40 that was similar in wild-type and IL-10KO mice. In vivo blockade of the CD28-B7 or CD40-CD40L interactions following infection of IL-10KO mice with T. gondii did not affect serum levels of IFN-gamma or IL-12, nor did it prevent death in these mice. However, when both pathways were blocked, the IL-10KO mice survived the acute phase of infection and had reduced serum levels of IFN-gamma and alanine transaminase as well as decreased expression of inducible nitric oxide synthase in the liver and spleen. Analysis of parasite-specific recall responses from infected IL-10KO mice revealed that blockade of the CD40-CD40L interaction had minimal effects on cytokine production, whereas blockade of the CD28-B7 interaction resulted in decreased production of IFN-gamma but not IL-12. Further reduction of IFN-gamma production was observed when both costimulatory pathways were blocked. Together, these results demonstrate that the CD28-B7 and CD40-CD40L interactions are involved in the development of infection-induced immunopathology in the absence of IL-10.

Solar eclipses of Phobos and Deimos observed from the surface of Mars

The small martian satellites Phobos and Deimos orbit in synchronous rotation with inclinations of only 0.01 degrees and 0.92 degrees , respectively, relative to the planet's equatorial plane. Thus, an observer at near-equatorial latitudes on Mars could occasionally observe solar eclipses by these satellites (see ref. 1, for example). Because the apparent angular diameter of the satellites is much smaller than that of the Sun, however, such events are more appropriately referred to as transits. Transit data can be used for correcting and refining the orbital ephemerides of the moons. For example, Phobos is known to exhibit a secular acceleration that is caused by tidal dissipation within Mars. Long-term, accurate measurements are needed to refine the magnitude and origin of this dissipation within the martian interior as well as to refine the predicted orbital evolution of both satellites. Here we present observations of six transits of Phobos and Deimos across the solar disk from cameras on Mars aboard the Mars Exploration Rovers Spirit and Opportunity. These are the first direct imaging observations of satellites transiting the Sun from the surface of another planet.

How useful are the SF-36 sub-scales in older people? Mokken scaling of data from the HALCyon programme

PURPOSE

To evaluate two psychometric properties of SF-36, namely unidimensionality and reliability.

METHODS

The data are from three cohorts in the HALCyon collaborative research programme into healthy ageing: Aberdeen Birth Cohort 1936 (n = 428), Hertfordshire Ageing Study (n = 358) and Hertfordshire Cohort Study (n = 3,216). The Mokken scaling model was applied to each sub-scale of SF-36 to evaluate unidimensionality as indicated by scalability. The lower bound for internal consistency reliability was determined by Cronbach's alpha.

RESULTS

All six sub-scales of SF-36, with the exception of general health (GH) and mental health (MH), demonstrated strong scalability (0.5 ≤ H < 1). The results were consistent across all 3 cohorts. Both GH and MH showed medium scalability (0.4 ≤ H <0.55), although individual items 'sick easier..', 'as healthy as..' and 'expect to get worse' of the GH sub-scale and 'nervous', 'happy' in the MH sub-scale had low scalability (H < 0.4) in the oldest cohort (aged 73-83). Cronbach's alphas for all sub-scales were between 0.70 and 0.92.

CONCLUSIONS

The unidimensionality and reliability of the sub-scales of SF-36 are sufficient to make this a useful measure of health-related quality of life in older people. Caution is needed when interpreting the results for GH and MH in the oldest cohort due to the poor unidimensionality.

Process evaluation for the FEeding Support Team (FEST) randomised controlled feasibility trial of proactive and reactive telephone support for breastfeeding women living in disadvantaged areas

OBJECTIVE

To assess the feasibility, acceptability and fidelity of a feeding team intervention with an embedded randomised controlled trial of team-initiated (proactive) and woman-initiated (reactive) telephone support after hospital discharge.

DESIGN

Participatory approach to the design and implementation of a pilot trial embedded within a before-and-after study, with mixed-method process evaluation.

SETTING

A postnatal ward in Scotland.

SAMPLE

Women initiating breast feeding and living in disadvantaged areas.

METHODS

Quantitative data: telephone call log and workload diaries. Qualitative data: interviews with women (n=40) with follow-up (n=11) and staff (n=17); ward observations 2 weeks before and after the intervention; recorded telephone calls (n=16) and steering group meetings (n=9); trial case notes (n=69); open question in a telephone interview (n=372). The Framework approach to analysis was applied to mixed-method data.

MAIN OUTCOME MEASURES

Quantitative: telephone call characteristics (number, frequency, duration); workload activity. Qualitative: experiences and perspectives of women and staff.

RESULTS

A median of eight proactive calls per woman (n=35) with a median duration of 5 min occurred in the 14 days following hospital discharge. Only one of 34 control women initiated a call to the feeding team, with women undervaluing their own needs compared to others, and breast feeding as a reason to call. Proactive calls providing continuity of care increased women's confidence and were highly valued. Data demonstrated intervention fidelity for woman-centred care; however, observing an entire breast feed was not well implemented due to short hospital stays, ward routines and staff-team-woman communication issues. Staff pragmatically recognised that dedicated feeding teams help meet women's breastfeeding support needs in the context of overstretched and variable postnatal services.

CONCLUSIONS

Implementing and integrating the FEeding Support Team (FEST) trial within routine postnatal care was feasible and acceptable to women and staff from a research and practice perspective and shows promise for addressing health inequalities.

TRIAL REGISTRATION

ISRCTN27207603. The study protocol and final report is available on request.