The structure of mouse HP1 suggests a unique mode of single peptide recognition by the shadow chromo domain dimer

The heterochromatin protein 1 (HP1) family of proteins is involved in gene silencing via the formation of heterochromatic structures. They are composed of two related domains: an N-terminal chromo domain and a C-terminal shadow chromo domain. Present results suggest that chromo domains may function as protein interaction motifs, bringing together different proteins in multi-protein complexes and locating them in heterochromatin. We have previously determined the structure of the chromo domain from the mouse HP1beta protein, MOD1. We show here that, in contrast to the chromo domain, the shadow chromo domain is a homodimer. The intact HP1beta protein is also dimeric, where the interaction is mediated by the shadow chromo domain, with the chromo domains moving independently of each other at the end of flexible linkers. Mapping studies, with fragments of the CAF1 and TIF1beta proteins, show that an intact, dimeric, shadow chromo domain structure is required for complex formation.

Structure of the chromatin binding (chromo) domain from mouse modifier protein 1

The structure of a chromatin binding domain from mouse chromatin modifier protein 1 (MoMOD1) was determined using nuclear magnetic resonance (NMR) spectroscopy. The protein consists of an N-terminal three-stranded anti-parallel beta-sheet which folds against a C-terminal alpha-helix. The structure reveals an unexpected homology to two archaebacterial DNA binding proteins which are also involved in chromatin structure. Structural comparisons suggest that chromo domains, of which more than 40 are now known, act as protein interaction motifs and that the MoMOD1 protein acts as an adaptor mediating interactions between different proteins.

Dual epitope recognition by the VASP EVH1 domain modulates polyproline ligand specificity and binding affinity

The Ena-VASP family of proteins act as molecular adaptors linking the cytoskeletal system to signal transduction pathways. Their N-terminal EVH1 domains use groups of exposed aromatic residues to specifically recognize 'FPPPP' motifs found in the mammalian zyxin and vinculin proteins, and ActA protein of the intracellular bacterium Listeria monocytogenes. Here, evidence is provided that the affinities of these EVH1-peptide interactions are strongly dependent on the recognition of residues flanking the core FPPPP motifs. Determination of the VASP EVH1 domain solution structure, together with peptide library screening, measurement of individual K(d)s by fluorescence titration, and NMR chemical shift mapping, revealed a second affinity-determining epitope present in all four ActA EVH1-binding motifs. The epitope was shown to interact with a complementary hydrophobic site on the EVH1 surface and to increase strongly the affinity of ActA for EVH1 domains. We propose that this epitope, which is absent in the sequences of the native EVH1-interaction partners zyxin and vinculin, may provide the pathogen with an advantage when competing for the recruitment of the host VASP and Mena proteins in the infected cell.

Are diverse signalling pathways integrated in the regulation of arabidopsis antioxidant defence gene expression in response to excess excitation energy?

When low-light-grown Arabidopsis rosettes are partially exposed to excess light (EL), the unexposed leaves become acclimated to excess excitation energy (EEE) and consequent photo-oxidative stress. This phenomenon, termed systemic acquired acclimation (SAA), is associated with redox changes in the proximity of photosystem II, changes in foliar H2O2 content and induction of antioxidant defences. The induction of extra-plastidial antioxidant systems is important in the protection of the chloroplast under EL conditions. A larger range of transcripts encoding different antioxidant defence enzymes may be induced in the systemically acclimated leaves and these include those encoded by the glutathione peroxidase (GPX2) and glutathione-S-transferase (GST) genes, which are also highly induced in the hypersensitive response and associated systemic acquired resistance (SAR) in incompatible plant-pathogen interactions. Furthermore, the expression of the SAR-inducible pathogenesis-related protein gene, PR2, is enhanced in SAA leaves. Wounded leaf tissue also shows enhanced systemic induction of a cytosolic ascorbate peroxidase gene (APX2) under EL conditions. These and other considerations, suggest H2O2 and other reactive oxygen species (ROS) could be the common factor in signalling pathways for diverse environmental stresses. These effects may be mediated by changes in the level and redox state of the cellular glutathione pool. Mutants with constitutive expression of a normally EL-inducible APX2 gene have much reduced levels of foliar glutathione. The expression of APX1 and APX3, encoding cytosolic and peroxisome-associated isoforms, respectively, are also under phytochrome-A-mediated control. The expression of these genes is tightly linked to the greening of plastids in etiolated seedlings. These data suggest that part of the developmental processes that bring about the acclimation of leaves to high light includes the configuration of antioxidant defences. Therefore, the linkage between immediate responses of leaves to EL, acclimation of chloroplasts to EEE and the subsequent changes to leaf form and function in high light could be mediated by the activity of foliar antioxidant defences and changes in the concentration of ROS.

Changes in haemoglobin during interferon alpha-2b plus ribavirin combination therapy for chronic hepatitis C virus infection

Interferon alpha and ribavirin (RBV) combination therapy is associated with decreases in haemoglobin (Hb) concentrations and anaemia. The aim of this analysis was to better characterize the magnitude and frequency of Hb changes and risk factors. This retrospective analysis evaluated treatment-related changes in Hb in 677 patients who participated in either of two interferon alpha-2b plus RBV studies for chronic hepatitis C virus (HCV) infection. Study 1 included 192 interferon alpha-naïve patients randomized to receive RBV 1000-1200 mg/day plus interferon alpha-2b 3 million IU daily or three times weekly for 48 weeks. Study 2 included 485 interferon alpha-experienced patients randomized to receive RBV 1000-1200 mg daily plus interferon alpha-2b 3 million IU daily or three times weekly for 4 weeks, followed by three times weekly dosing for 44 weeks. More than 50% of all patients experienced a decrease in Hb > or =30 g/L. Women were 4.4 times as likely as men to experience a Hb level of <100 g/L; however, men were at a 40% higher risk to experience a Hb decline of >30 g/L from baseline. Daily use of interferon alpha-2b did not impact the magnitude of Hb decrease. In this pooled analysis, RBV dose reduction resulted in increases in Hb concentration of approximately 10 g/L. Lower baseline creatinine clearance, higher baseline Hb levels and increased age were independently associated with increased risk of Hb decreases of >27.7%. Lower baseline weight was not associated with increased risk of Hb decrease. Substantial Hb decreases occur frequently with interferon alpha/RBV combination therapy. Sex, the magnitude of the Hb decline and renal function are potentially important factors to consider in patients receiving RBV. Further research is needed to determine the impact on virological response and to develop strategies to manage the medical consequences.

Zidovudine use but not weight-based ribavirin dosing impacts anaemia during HCV treatment in HIV-infected persons

Anaemia during peginterferon (PEG-IFN) and ribavirin (RBV) therapy is common in human immunodeficiency virus/hepatitis C virus (HIV/HCV)-coinfected patients despite the use of lower doses of RBV than are recommended for HIV-seronegative persons. In addition, concurrent zidovudine (ZDV) may exacerbate the anaemia caused by PEG-IFN and RBV. We retrospectively analysed the incidence of anaemia, RBV dose reduction and epoetin-alpha (EPO) use among coinfected patients treated with PEG-IFN and weight-based RBV (800-1400 mg/day) who enrolled in two clinical trials and had haemoglobin (Hb) levels assessed at baseline and after 4 and/or 12 weeks of HCV treatment. Overall, 217 patients were included; pre-treatment Hb levels (mean 14.7 g/dL) were similar in all patients, including ZDV users (29% of patients). After 4 weeks of therapy, the mean Hb decline was greater among ZDV recipients (3.13 g/dL) compared with those on other anti-retroviral treatment (ART) (2.13 g/dL) or on no ART (1.47 g/dL) (P < 0.0001). RBV dose reduction and EPO use were more common in patients taking ZDV compared with those not taking ZDV (P < 0.0001). RBV dose was not associated with Hb reduction, RBV dose reduction or EPO use. Virologic response after 12 weeks of therapy and the treatment discontinuation rate did not differ by ZDV use. The use of ZDV but not weight-based RBV dosing was associated with an increased risk of anaemia, RBV dose reduction or EPO use in coinfected patients treated with PEG-IFN/RBV. However, ZDV use was not associated with higher rates of treatment discontinuation or lower early virologic response rates. HIV and hepatitis C care providers should be cognizant of these data.

Relativism and stations of epistemic doubt

This sequence of studies examined the role that relativistic thinking plays in the cognitive and social-emotional lives of adolescents. Study 1 introduces an assessment strategy and associated descriptive model employed in evaluating how 70 concrete and formal operational adolescents differently interpret and resolve problems involving competing knowledge claims. A second study explored the relations between the epistemic orientations evidenced by 61 of these subjects and their current level of identity development. Study 3 compared the epistemic assumptions of a group of 29 psychiatrically hospitalized adolescents with those of a matched group of normal controls. Results from these studies indicate that relativistic approaches to problems of belief entitlement are: a) routinely characteristic of most normal adolescents; b) available to formal operational, but not concrete operational individuals; c) associated with more mature ego-identity statuses; and d) typically absent in groups of psychiatrically hospitalized youth.

Patient-centred care to improve dietetic practice: an integrative review

BACKGROUND

Patient-centred care (PCC) is associated with significant improvements in patients' health outcomes and healthcare systems. There is an opportunity to better understand PCC in dietetics. Thus, the present integrative review aims to critically synthesise literature relating to PCC in dietetics.

METHODS

A systematic literature search was conducted between February and March 2016. Studies were included if they (i) involved dietitians and/or patients who had participated in an individual dietetic consultation; (ii) related to one or more components of PCC; and (iii) were empirical full-text studies in English, involving adult participants, published between 1997 and 2016. Following title and abstract screening, full texts were retrieved and independently assessed for inclusion by two of the investigators. Two independent investigators conducted data extraction and quality assessment using the Mixed Methods Appraisal Tool. Study findings were analysed thematically using meta-synthesis. Twenty-seven studies met the inclusion criteria.

RESULTS

Six themes were discovered inductively: (i) establishing a positive dietitian-patient relationship; (ii) displaying humanistic behaviours; (iii) using effective communication skills; (iv) individualising and adapting care; (v) redistributing power to the patient; and (vi) lacking time for PCC practices. The first three themes were closely related. Studies used a broad range of methodological designs. Limitations of the studies included a lack of reflexivity and a lack of representativeness of the study population.

CONCLUSIONS

It is apparent that dietitians require good communication skills and humanistic qualities to build positive relationships with patients. Patients strongly desire individualised nutrition care and greater involvement in care. Ensuring dietitians are able to incorporate patient-centred practises during care requires further research.

A protocol for identification of early bulbar signs in amyotrophic lateral sclerosis

The purpose of this project is to identify characteristics that may be of assistance in establishing the diagnosis and monitoring early progression of bulbar dysfunction in patients with Amyotrophic Lateral Sclerosis (ALS). Early identification of bulbar dysfunction would assist in clinical trials and management decisions. A database of 218 clinic visits of patients with ALS was developed and formed the basis for these analyses. As a framework for the description of our methodology, the Disablement Model [World Health Organization. WHO International classification of impairment, activity, and participation: beginner's guide. In: WHO, editor. Beta-1 draft for field trials; 1999] was utilized. Our data identified that the strongest early predictors of bulbar speech dysfunction include altered voice quality (laryngeal control), speaking rate, and communication effectiveness. A protocol for measuring these speech parameters was therefore undertaken. This paper presents the protocol used to measure these bulbar parameters.

Solution structure of the receptor tyrosine kinase EphB2 SAM domain and identification of two distinct homotypic interaction sites

The sterile alpha motif (SAM) is a protein interaction domain of around 70 amino acids present predominantly in the N- and C-termini of more than 60 diverse proteins that participate in signal transduction and transcriptional repression. SAM domains have been shown to homo- and hetero-oligomerize and to mediate specific protein-protein interactions. A highly conserved subclass of SAM domains is present at the intracellular C-terminus of more than 40 Eph receptor tyrosine kinases that are involved in the control of axonal pathfinding upon ephrin-induced oligomerization and activation in the event of cell-cell contacts. These SAM domains appear to participate in downstream signaling events via interactions with cytosolic proteins. We determined the solution structure of the EphB2 receptor SAM domain and studied its association behavior. The structure consists of five helices forming a compact structure without binding pockets or exposed conserved aromatic residues. Concentration-dependent chemical shift changes of NMR signals reveal two distinct well-separated areas on the domains' surface sensitive to the formation of homotypic oligomers in solution. These findings are supported by analytical ultracentrifugation studies. The conserved Tyr932, which was reported to be essential for the interaction with SH2 domains after phosphorylation, is buried in the hydrophobic core of the structure. The weak capability of the isolated EphB2 receptor SAM domain to form oligomers is supposed to be relevant in vivo when the driving force of ligand binding induces receptor oligomerization. A formation of SAM tetramers is thought to provide an appropriate contact area for the binding of a low-molecular-weight phosphotyrosine phosphatase and to initiate further downstream responses.

Association between night-time surgery and occurrence of intraoperative adverse events and postoperative pulmonary complications

BACKGROUND

The aim of this post hoc analysis of a large cohort study was to evaluate the association between night-time surgery and the occurrence of intraoperative adverse events (AEs) and postoperative pulmonary complications (PPCs).

METHODS

LAS VEGAS (Local Assessment of Ventilatory Management During General Anesthesia for Surgery) was a prospective international 1-week study that enrolled adult patients undergoing surgical procedures with general anaesthesia and mechanical ventilation in 146 hospitals across 29 countries. Surgeries were defined as occurring during 'daytime' when induction of anaesthesia was between 8:00 AM and 7:59 PM, and as 'night-time' when induction was between 8:00 PM and 7:59 AM.

RESULTS

Of 9861 included patients, 555 (5.6%) underwent surgery during night-time. The proportion of patients who developed intraoperative AEs was higher during night-time surgery in unmatched (43.6% vs 34.1%; P<0.001) and propensity-matched analyses (43.7% vs 36.8%; P=0.029). PPCs also occurred more often in patients who underwent night-time surgery (14% vs 10%; P=0.004) in an unmatched cohort analysis, although not in a propensity-matched analysis (13.8% vs 11.8%; P=0.39). In a multivariable regression model, including patient characteristics and types of surgery and anaesthesia, night-time surgery was independently associated with a higher incidence of intraoperative AEs (odds ratio: 1.44; 95% confidence interval: 1.09-1.90; P=0.01), but not with a higher incidence of PPCs (odds ratio: 1.32; 95% confidence interval: 0.89-1.90; P=0.15).

CONCLUSIONS

Intraoperative adverse events and postoperative pulmonary complications occurred more often in patients undergoing night-time surgery. Imbalances in patients' clinical characteristics, types of surgery, and intraoperative management at night-time partially explained the higher incidence of postoperative pulmonary complications, but not the higher incidence of adverse events.

CLINICAL TRIAL REGISTRATION

NCT01601223.

The origin of the alpha-domain intermediate in the folding of hen lysozyme

Stopped-flow fluorescence and circular dichroism spectroscopy have been used in conjunction with quenched-flow hydrogen exchange labelling, monitored by electrospray ionization mass spectrometry, to compare the refolding kinetics of hen egg-white lysozyme at 20 degrees C and 50 degrees C. At 50 degrees C there is clear evidence for distinct fast and slow refolding populations, as observed at 20 degrees C, although folding occurs significantly more rapidly. The folding process is, however, substantially more cooperative at the higher temperature. In particular, the transient intermediate on the major refolding pathway at 20 degrees C, having persistent native-like structure in the alpha-helical domain of the protein, is not detected by hydrogen exchange labelling at 50 degrees C. In addition, the characteristic maximum in negative ellipticity and the minimum in fluorescence intensity observed in far UV CD and intrinsic fluorescence experiments at 20 degrees C, respectively, are not seen at 50 degrees C. Addition of 2 M NaCl to the refolding buffer at 50 degrees C, however, regenerates both the hydrogen exchange and optical properties associated with the alpha-domain intermediate but has no significant effect on the overall refolding kinetics. Together with previous findings, these results indicate that non-native interactions within the alpha-domain intermediate are directly responsible for the unusual optical properties observed during refolding, and that this intermediate accumulates as a consequence of its intrinsic stability in a folding process where the formation of stable structure in the beta-domain constitutes the rate-limiting step for the majority of molecules.

Effect of and gram-negative anaerobic bacteria on the development of bovine pyometra

Fifteen lactating Holstein cows were used in a trial designed to evaluate the effectiveness of intrauterine inoculation (challenge) of Actinomyces pyogenes (A) alone or in combination with Fusobacterium necrophorum (F) and Bacteroides melaninogenicus (B) to induce pyometra. Cows were assigned to one of five groups: A (n = 3), AB (n = 3), AF (n = 3), ABF (n = 3) or C (control, broth medium alone; n = 3). All cows exhibited estrus 12 or 13 d prior to challenge (Day 0=first day of challenge). During the prechallenge period, the reproductive tract of each cow was palpated per rectum and uterine fluid aspirates for culture and uterine biopsies were also obtained. All cows received an intravenous injection of 5,000 IU of human chorionic gonadotropin (hCG; Day 5) and an intrauterine infusion of 40 ml of 0.7% iodine solution (Day 1). Cows were then inoculated on Days 0, 1 and 2 of the experiment. Sequential palpations of the reproductive tracts, samples of uterine fluid for culture and uterine biopsies were performed for a total of 30 d after the first inoculation. A cow was diagnosed as having pyometra when purulent uterine fluid and a corpus luteum were detected by palpation per rectum. The number of cows that developed pyometra in Group A was 2 of 3, in Group AB 3 of 3, in Group AF 3 of 3, in Group ABF 3 of 3 and in Group C 0 of 3. Cows with pyometra did not exhibit estrus. In 7 of 11 cows, pyometra persisted for more than 21 d. In cows that developed pyometra, the same species of bacteria infused into the uterus were usually recovered one or more times during the postchallenge period. When clinical pyometra was diagnosed, histologic endometritis was invariably present. Histologic endometritis and concurrent isolation of A . pyogenes alone or A . pyogenes with gram-negative anaerobic bacteria occurred in 91.7% of samples during the postchallenge period. Regardless of bacterial treatment, gram-negative anaerobic bacteria were frequently isolated with A . pyogenes during this period.

The use of DNA probes to monitor minimal residual disease in childhood acute lymphoblastic leukaemia

DNA probes to both the joining region (JH) of the immunoglobulin heavy chain gene (IgH) and to the beta chain of the T-cell antigen receptor complex (TCR) have been used as tumour-specific markers to monitor the rearrangements of the IgH chain gene and the TCR beta gene in the blast cells of children presenting with acute lymphoblastic leukaemia (ALL) of B or T cell origin. Blast cells from 68 children with early B cell ALL and eight with T-ALL were examined at presentation, at day 28 after commencement of therapy and at varying times thereafter. An additional 43 patients (42 with B cell ALL, one with T-ALL) were studied both at presentation, at completion of their 2-year treatment course and 3 months later. Twelve patients, drawn from both these groups, were studied at relapse as were a further eight patients in whom an extramedullary relapse had occurred. Persistence of clonally-derived cells as a predictor of early relapse was seen in the day 28 bone marrows of 11/76 newly-diagnosed children (nine early B and two T-ALL) followed by rapid, overt relapse in four of the early B ALL cases. No minimal residual disease (MRD) was detected in bone marrows from any of the 43 patients completing their 2-year treatment course, but six of these subsequently relapsed at varying time periods thereafter. Identical patterns of rearrangement at both presentation and relapse were seen in most cases. Oligoclonality, or multiple IgH chain gene rearrangements was seen in the blast cells of 15% of patients with early B cell ALL. No correlation between oligoclonality, high white count, unfavourable phenotype or abnormal karyotype could, however, be ascertained.

Working memory, metacognitive uncertainty, and belief bias in syllogistic reasoning

Studies of syllogistic reasoning have shown that the size of the belief bias effect varies with manipulations of logical validity and problem form. This paper presents a mental models-based account, which explains these findings in terms of variations in the working-memory demands of different problem types. We propose that belief bias may reflect the use of a heuristic that is applied when a threshold of uncertainty in one's processing--attributable to working-memory overload--is exceeded during reasoning. Three experiments are reported, which tested predictions deriving from this account. In Experiment 1, conclusions of neutral believability were presented for evaluation, and a predicted dissociation was observed in confidence ratings for responses to valid and invalid arguments, with participants being more confident in the former. In Experiment 2, an attempt to manipulate working-memory loads indirectly by varying syllogistic figure failed to produce predicted effects upon the size of the belief bias effect. It is argued that the employment of a conclusion evaluation methodology minimized the effect of the figural manipulation in this experiment. In Experiment 3, participants' articulatory and spatial recall capacities were calibrated as a direct test of working-memory involvement in belief bias. Predicted differences in the pattern of belief bias observed between high and low spatial recall groups supported the view that limited working memory plays a key role in belief bias.

Light-mediated antifungal activity of Echinacea extracts

This study demonstrated that plant extracts containing acetylenic isobutylamides and polyacetylenes, previously reported as occurring in Echinacea, have phototoxic antimicrobial activity against fungi, including clinically relevant pathogenic fungi. Results show that hexane extracts of Echinacea variably inhibit growth of yeast strains of Saccharomyces cerevisiae, Candida shehata, C. kefyr, C. albicans, C. steatulytica and C. tropicalis under near UV irradiation (phototoxicity) and to a lower extent without irradiation (conventional antifungal activity). The presence of polyacetylenes and alkylamides in extracts of different organs was confirmed in Echinacea purpurea by HPLC in agreement with previously reported data in the literature, and was related to phototoxic activity. Two representative pure compounds, undeca-2E,4Z-diene-8,10-diynoic acid isobutylamide and dodeca-2E,4E,8Z,10E/Z-tetraenoic acid isobutylamide, were isolated from Echinacea purpurea root extracts, and compared in a disk assay (5 micrograms/disk) with the highly conjugated trideca-1-ene-3,5,7,9,10-pentayne (previously isolated in our laboratory and found here in E. purpurea). Significant phototoxicity was demonstrated by pure trideca-1-ene-3,5,7,9,10-pentayne, while only minor phototoxicity was induced by the other two acetylenic compounds. Phototoxic activity of Echinacea spp. is primarily attributed to the ketoalkenes and ketoalkynes abundantly present in the roots.

Effects on reproductive performance of administration of GnRH to early postpartum dairy cows

Three-hundred and thirty-five lactating dairy cows from two herds were used to compare the effects on reproductive performance of intramuscular injections of 100 micrograms gonadotropin-releasing hormone (GnRH), 250 micrograms GnRH or saline given on day 13, 14 or 15 postpartum. The incidence of ovarian cysts or uterine infections was not reduced after GnRH injection. Culling rate for infertility did not differ in either herd between GnRH- and saline-treated control cows. In the herd in which breeding began earlier in the postpartum period (Herd B), injection of 250 micrograms GnRH resulted in a better (P < .05) calving to conception interval (81 vs 96 days), better first service conception rate (74.5 vs 56.0%), better overall conception rate (70.6 vs 51.1%) and a lower number of services per conception (1.23 vs 1.74) than in the controls. In reproductively well-managed herds, injections of 250 micrograms GnRH, given to lactating dairy cows 2 weeks after calving, may increase fertility.

Patients' perceptions and experiences of patient-centred care in dietetic consultations

BACKGROUND

Patient-centred care (PCC) is essential to quality healthcare. However, there is a paucity of research on PCC in dietetics, particularly regarding patients' experiences and perspectives of PCC. We aimed to enhance our understanding of PCC in dietetics by exploring patients' perceptions and experiences of PCC in individual dietetic consultations.

METHODS

The present study used qualitative methods, situated in a constructivist-interpretivist paradigm. Maximum variation purposive sampling was used to recruit English speaking adult participants who had participated in ≥1 dietetic consultations for nutrition care. Individual semi-structured interviews explored participants' perceptions and experiences of PCC in dietetic consultations. Data were analysed thematically.

RESULTS

Eleven patients were interviewed between September and November 2016. Four overarching themes emerged: (i) fostering and maintaining caring relationships; (ii) delivering individualised care; (iii) enabling patient involvement; and (iv) taking control of one's own health.

CONCLUSIONS

PCC is important to patients. Thus, there is opportunity for dietitians to enhance the care they provide by adopting patient-centred practices. As the first study of its kind, these findings can inform future dietetic practice, education and research by contributing patients' perspectives of PCC. By understanding patients' unique needs and preferences, dietitians can better align their practice with a patient-centred approach. Furthermore, these findings are useful for informing future dietetic research and education.

Development of a test of physical performance for the nursing home setting

PURPOSE

This study was undertaken to develop a performance-based instrument to measure a range of function present among nursing home (NH) residents and to establish the reliability and validity of the measures.

DESIGN AND METHODS

Fourteen items integral to daily life in a NH setting were administered to 95 NH residents with sufficient cognitive ability to follow a one-step command at baseline, 1 week later, and 6 months later. Intraclass correlation coefficients and Cronbach's coefficient alpha were calculated for reliability estimates. The Minimum Data Set (MDS), Katz, and Multidimensional Observational Scale for Elderly Subjects (MOSES) were used to establish concurrent validity. Factor analysis, correlation matrices, and other objective criteria were used for item reduction.

RESULTS

Test-retest reliability for items ranged between.73 and.93. Factor analysis and correlations between Nursing Home Physical Performance Test (NHPPT) items and scales with measures of activities of daily living (ADL) suggest that the NHPPT taps aspects of gross motor function (Factor 1) and fine motor coordination and task sequencing (Factor 2) required for ADL function and mobility. The NHPPT may also tap aspects of ADL function and mobility not measured by the MDS (r = -.72-.75), MOSES (r = -.82-.84), or Katz (r = -.75-.77) scales. Effect sizes based on mean change scores were larger for the NHPPT scales (.38-.53) than for the other functional scales (.27-.33).

IMPLICATIONS

The NHPPT is a reliable performance-based instrument that discriminates among frail NH residents. Further studies are necessary to assess the value of this instrument for prediction and monitoring of functional status in the NH.

Disseminated infection with Balamuthia mandrillaris in a dog

Bilateral chronic granulomatous nephritis and meningoencephalitis were diagnosed on necropsy of a 2-year-old male Great Dane dog. The causative agent was identified as Balamuthia mandrillaris, based on morphologic features, immunohistochemical staining, and deoxyribonucleic acid detection using the polymerase chain reaction with newly designed primer pairs. Trophozoite and cystic forms of the amoeba were evident within the kidneys and brain parenchyma. This is the first report on a B. mandrillaris infection in a dog.

The NMR structure of the 47-kDa dimeric enzyme 3,4-dihydroxy-2-butanone-4-phosphate synthase and ligand binding studies reveal the location of the active site

Recent developments in NMR have extended the size range of proteins amenable to structural and functional characterization to include many larger proteins involved in important cellular processes. By applying a combination of residue-specific isotope labeling and protein deuteration strategies tailored to yield specific information, we were able to determine the solution structure and study structure-activity relationships of 3,4-dihydroxy-2-butanone-4-phosphate synthase, a 47-kDa enzyme from the Escherichia coli riboflavin biosynthesis pathway and an attractive target for novel antibiotics. Our investigations of the enzyme's ligand binding by NMR and site-directed mutagenesis yields a conclusive picture of the location and identity of residues directly involved in substrate binding and catalysis. Our studies illustrate the power of state-of-the-art NMR techniques for the structural characterization and investigation of ligand binding in protein complexes approaching the 50-kDa range in solution.

Setting the scene for the paramedic in primary care: a review of the literature

Recognition of the paramedic "profession" began in 2003, with the introduction of statutory registration and the promotion of graduate entry. This paper explores the published evidence which surrounds paramedic practice in an attempt to identify the skills, training, and professional capacity which paramedics of the future will require. A systematic analysis was carried out of key reviews and commentaries published between January 1995 and April 2004, and informal discussions with experts and researchers in the field were undertaken. There remains little high quality published evidence with which to validate many aspects of current paramedic practice. To keep pace with service developments, paramedic training must embrace the complexities of autonomous practice. Undoubtedly in the short term, paramedics must be taught to appropriately identify and manage a far wider range of commonly occurring conditions, minor illnesses, and trauma. However, in the longer term, and more importantly, paramedics must learn to work together to take ownership of the basic philosophies of their practice, which must have their foundation in valid and reliable research.

A simple test of central processing speed: an extension of the Short Blessed Test

OBJECTIVE

To evaluate the efficacy and reliability of a simple measure of central processing speed: the time to recite the months of the year in reverse order, from the Short Blessed Test of Orientation, Concentration, and Memory (SBT).

DESIGN

Cross-sectional and longitudinal designs were used to establish validity and test-retest reliability.

SETTING

Participants' homes and by telephone interview.

PARTICIPANTS

An age-stratified sample of 120 community-dwelling women, aged 67-94, randomly selected from Medicare recipients of the St. Louis Metropolitan Statistical Area.

MEASUREMENTS

Dependent variables were the SBT, the Trail Making Test, computer-generated simple and choice reaction time, and time to say the months of the year backward (TMYB). The independent variable was age.

RESULTS

Significant Pearson product-moment correlations were obtained for Trail Making and TMYB with a simple and choice reaction time after controlling for age and cognitive status. An exponential relationship was observed between age and TMYB, expressed both cross-sectionally and as rate of change. Test-retest reliability for TMYB was 0.90.

CONCLUSIONS

TMYB is a valid and reliable measure of central processing speed that compares favorably to the more elaborate and time-consuming Trail Making B test. Because of its simplicity and ease of administration, this test provides the clinician with a practical measure of central processing speed. TMYB extends the utility of the widely used Short Blessed Test by measuring this additional and important domain of brain function.

Phenotypic differences in dextromethorphan metabolism

Polymorphic differences in dextromethorphan metabolism were observed in three studies conducted in a total of 44 subjects (of Dutch origin) administered 60 mg dextromethorphan hydrobromide as an OROS tablet. Mean plasma dextromethorphan (DM) concentrations after a single dose and at steady state were 4-75 times higher in the poor metabolizers (PM) relative to the extensive metabolizers (EM). Following a single dose, the mean areas under the plasma concentration-time curve (AUC, 0-24 hr) of DM, total dextrorphan (DR), and total 3-hydroxymorphinan (HM) were 6.9-fold higher, 17.4-fold lower, and 11-fold lower, respectively, for the PM than for the EM. Correspondingly, steady-state AUC values were 52.8 times higher, 6.7 times lower, and 3.3 times lower for DM, total DR, and total HM, respectively, for the PM relative to the EM. Drug/metabolite ratios (DMR) for amounts excreted in the urine of DR and HM indicated polymorphism in O-demethylation of DM since DMR for PM was 352 and 338 times higher than that for EM for DR and HM, respectively. However, polymorphism in N-demethylation was not observed. Ratios of conjugated/free dextrorphan and 3-hydroxymorphinan excreted in the urine suggest also a lack of conjugative capacity in the PM, relative to the EM. The overall incidence of PM was 9.1% in this population.