Club-based and non-club-based physiotherapists' views on the psychological content of their practice when treating sports injuries.

The aim of the present study was to explore whether there were any differences in the psychological content of practice between club-contracted and non-club-contracted physiotherapists when treating sports injuries. Eighty-seven certified physiotherapists (non-club contracted N = 42, club contracted N = 45) from the United Kingdom completed a modified version of the Athletic Training and Sport Psychology Questionnaire (ATSPQ). Results revealed significant between-group differences in psychological skills use and the importance of psychological skills knowledge. Non-club-contracted physiotherapists reported a higher use of improving social support and higher-order psychological skills (e.g., reducing depression, stress, and anxiety) and rated knowledge of these psychological skills to be more important whilst club-contracted physiotherapists reported a higher use of short-term goal settings. These findings suggest that non-club-based physiotherapists may approach the treatment of injured athletes in a different way to their club-based counterparts. Results suggest athletes treated outside of the club system may experience a different recovery process.

Prognostic value of troponin T in hemodialysis patients is independent of comorbidity.

BACKGROUND: Patients on long-term hemodialysis have a high mortality. Various clinical and biochemical markers are of prognostic value. Cardiac troponin T (cTnT) is a sensitive and specific marker for myocardial damage. Asymptomatic dialysis patients have a high prevalence of cTnT concentrations above the diagnostic threshold for myocardial damage. There is controversy over whether this represents a false positive cTnT or an underlying pathology with a poor outcome. It is not known whether cTnT reflects comorbidity in these patients. METHODS: A cohort of 73 long-term hospital hemodialysis patients had cTnT estimated once prior to a mid-week dialysis. Samples were analyzed using the second-generation cTnT assay from Boehringer Mannheim on an Elecsys 1010 analyzer. The standard diagnostic threshold for myocardial damage of 0.1 ng/mL was used. A commonly employed measure of comorbidity (Khan) was applied at the time cTnT was measured. Patients were followed for 15 months. Mortality was used as the clinical end point. Kaplan-Meier survival analysis was employed and differences between groups were assessed using the Cox-Mantel log-rank test. RESULTS: Of the 73 patients, 20 were positive for cTnT and 53 were negative, at the cut-off of 0.1 ng/mL. At fifteen months, 65% of the positive patients were dead, whereas only 15% of the negative patients were dead. Survival analysis confirmed that this difference was statistically significant (P < 0.00001), and that the effect of cTnT on survival was independent of comorbidity. CONCLUSIONS: There is a high prevalence of positive cTnT in stable hemodialysis patients. A single estimation of cTnT in this group has significant prognostic value, independent of comorbidity.

Mutagenesis studies of the FeSII protein of Azotobacter vinelandii: roles of histidine and lysine residues in the protection of nitrogenase from oxygen damage.

The Azotobacter FeSII protein, also known as the Shethna protein, forms a protective complex with nitrogenase during periods when nitrogenase is exposed to oxygen. One possible mechanism for its action is an oxidation state-dependent conformational interaction with nitrogenase whereby the FeSII protein dissociates from the MoFe and Fe proteins of nitrogenase under reducing conditions. Herein we report the construction and characterization of five site-directed mutants of the FeSII protein (H12Q, H55Q, K14A, K15A, and the double mutant K14A/K15A) which were individually purified after being individually overexpressed in Escherichia coli. These mutant FeSII proteins maintain native-like assembly and orientation of the 2Fe-2S center on the basis of EPR and NMR spectroscopic characterization and their redox midpoint potentials, which are within 25 mV of that of the wild type protein. The abilities of the individual mutant proteins to protect nitrogenase were assessed by determining the remaining nitrogenase activities after adding each pure version back to extracts from an FeSII deletion strain, and then exposing the mixture to oxygen. In these assays, the H12Q mutant functioned as well as the wild type protein. However, mutation of His55, a few residues away from a cluster-liganding cysteine, results in much less efficient protection of nitrogenase. These results are consistent with pH titrations in both oxidation states, which show that His12 is insensitive to 2Fe-2S cluster oxidation state. His55's pK is weakly responsive to oxidation state, and the pK increase of 0. 16 pH unit upon 2Fe-2S cluster oxidation is indicative of ionization of another group between His55 and the 2Fe-2S cluster, which could modulate the FeSII protein's affinity for nitrogenase in a redox state-dependent manner. Both K14A and K15A mutant FeSII proteins partially lost their ability to protect nitrogenase, but the lysine double mutant lost almost all its protective ability. The nitrogenase component proteins in an Azotobacter strain bearing the double lysine mutation (in the chromosome) were degraded much more rapidly in vivo than those in the wild type strain under carbon substrate-limited conditions. These results indicate that the two lysines may have an important role in FeSII function, perhaps in the initial steps of recognizing the nitrogenase component proteins.

Heterologous biosynthesis and characterization of the [2Fe-2S]-containing N-terminal domain of Clostridium pasteurianum hydrogenase.

The primary structure of Clostridium pasteurianum hydrogenase I appears to be composed of modules suggesting that the various iron-sulfur clusters present in this enzyme might be segregated in structurally distinct domains. On the basis of this observation, a gene fragment encoding the 76 N-terminal residues of this enzyme has been expressed in Escherichia coli. The polypeptide thus produced contains a [2Fe-2S]n+ cluster of which the oxidized level (n = 2) has been monitored by UV-visible absorption, circular dichroism, and resonance Raman spectroscopy. This cluster can be reduced by dithionite or electrochemically to the n = 1 level which has been investigated by EPR and by low-temperature magnetic circular dichroism. The redox potential of the +2 to +1 transition is -400 mV (vs the normal hydrogen electrode). The spectroscopic and redox results indicate a [2Fe-2S]2+/+ chromophore coordinated by four cysteine ligands in a protein fold similar to that found in plant- and mammalian-type ferredoxins. Among the five cysteines present in the N-terminal hydrogenase fragment, four (in positions 34, 46, 49, and 62) are conserved in other sequences and are therefore the most likely ligands of the [2Fe-2S] site. The fifth cysteine, in position 39, can be dismissed on the grounds that the Cys39Ala mutation does not alter any of the properties of the iron-sulfur cluster. The spectroscopic signatures of this chromophore are practically identical with some of those reported for full-size hydrogenase. This confirms that C. pasteurianum hydrogenase I contains a [2Fe-2S] cluster and indicates that the polypeptide fold around the metal site of the N-terminal fragment is very similar, if not identical, to that occurring in the full-size protein. The N-terminal sequence of this hydrogenase is homologous to sequences of a number of proteins or protein domains, including a subunit of NADH-ubiquinone oxidoreductase of respiratory chains. From that, it can be anticipated that the structural domain isolated and described here is a building block of electron transfer complexes involved in various bioenergetic processes.

[2Fe-2S] to [4Fe-4S] cluster conversion in Escherichia coli biotin synthase.

The type and properties of the Fe-S cluster in recombinant Escherichia coli biotin synthase have been investigated in as-prepared and dithionite-reduced samples using the combination of UV-visible absorption and variable-temperature magnetic circular dichroism (VTMCD), EPR, and resonance Raman spectroscopies. The results confirm the presence of one S = 0 [2Fe-2S]2+ cluster in each subunit of the homodimer in aerobically purified samples, and the Fe-S stretching frequencies suggest incomplete cysteinyl-S coordination. However, absorption and resonance Raman studies show that anaerobic reduction with dithionite in the presence of 60% (v/v) ethylene glycol or glycerol results in near-stoichiometric conversion of two [2Fe-2S]2+ clusters to form one S = 0 [4Fe-4S]2+ cluster with complete cysteinyl-S coordination. The stoichiometry and ability to effect reductive cluster conversion without the addition of iron or sulfide suggest that the [4Fe-4S]2+ cluster is formed at the subunit interface via reductive dimerization of [2Fe-2S]2+ clusters. EPR and VTMCD studies indicate that more than 50% of the Fe is present as [4Fe-4S]+ clusters in samples treated with 60% (v/v) glycerol after prolonged dithionite reduction. The [4Fe-4S]+ cluster exists as a mixed spin system with S = 1/2 (g = 2. 044, 1.944, 1.914) and S = 3/2 (g = 5.6 resonance) ground states. Subunit-bridging [4Fe-4S]2+,+ clusters, that can undergo oxidative degradation to [2Fe-2S]2+ clusters during purification, are proposed to be a common feature of Fe-S enzymes that require S-adenosylmethionine and function by radical mechanisms involving the homolytic cleavage of C-H or C-C bonds, i.e., biotin synthase, anaerobic ribonucleotide reductase, pyruvate formate lyase, lysine 2, 3-aminomutase, and lipoic acid synthase. The most likely role for the [4Fe-4S]2+,+ cluster lies in initiating the radical mechanism by directly or indirectly facilitating reductive one-electron cleavage of S-adenosylmethionine to form methionine and the 5'-deoxyadenosyl radical. It is further suggested that oxidative cluster conversion to [2Fe-2S]2+ clusters may play a physiological role in these radical enzymes, by providing a method of regulating enzyme activity in response to oxidative stress, without irreversible cluster degradation.

Treatment of severe acute vascular rejection in a renal allograft with mycophenolate mofetil and high dose steroids.

A case of a highly sensitised haemodialysis patient who developed severe vascular rejection in her third renal allograft is presented. This severe rejection episode responded to mycophenolate mofetil (MMF) and high dose steroids.

Risk due to inactivity in physically capable older adults.

OBJECTIVES: This study examined the association between recreational physical activity among physically capable older adults and functional status, incidence of selected chronic conditions, and mortality over 3 and 6 years. METHODS: Data are from three sites of the Established Populations for Epidemiologic Studies of the Elderly. RESULTS: A high level of recreational physical activity reduced the likelihood of mortality over both 3 and 6 years. Moderate to high activity reduced the risk of physical impairments over 3 years; this effect diminishes after 6 years. A consistent relationship between activity and new myocardial infarction or stroke or the incidence of diabetes or angina was not found after 3 or 6 years. CONCLUSIONS: Findings suggest that physical activity offers benefits to physically capable older adults, primarily in reducing the risk of functional decline and mortality. Future work must use more objective and quantifiable measures of activity and assess changes in activity levels over time.

High blood pressure in the Western Isles: a comparative study with Dundee.

A screening programme for cardiovascular risk factors in men aged 50-59 was undertaken in North Uist, and the results compared with an age- and sex-matched control group from Dundee screened as part of the Scottish Heart Health Study. Blood pressure levels were higher in the Islanders than in controls (148 +/- 20/89 +/- 10 mmHg vs 134 +/- 19/84 +/- 11 mmHg (P less than 0.001). Analysis of standard twelve-lead electrocardiograms revealed a greater prevalence of left ventricular hypertrophy in the Islanders (51% vs 16%, P less than 0.005), suggesting that the recorded BP differences were real and not artefacts of measurement. The explanation for the higher BP on North Uist is less clear. Environmental factors that might influence BP including body mass index, the amount of exercise taken, alcohol consumption, dietary salt and potassium intake were similar in North Uist and Dundee. By contrast, an analysis of family names in the two centres indicated a greater degree of common ancestry in North Uist (28 surnames/84 islanders v 98 surnames/110 controls, P less than 0.001). These results suggest that known environmental causes of hypertension are not responsible for higher BP amongst men of North Uist, and this with the data on family names raises the possibility that genetic factors are more important.