Two-stage revision for prosthetic joint infection: predictors of outcome and the role of reimplantation microbiology

Objectives

We describe rates of success for two-stage revision of prosthetic joint infection (PJI), including data on reimplantation microbiology.

Methods

We retrospectively collected data from all the cases of PJI that were managed with two-stage revision over a 4 year period. Patients were managed with an antibiotic-free period before reimplantation, in order to confirm, clinically and microbiologically, that infection was successfully treated.

Results

One hundred and fifty-two cases were identified. The overall success rate (i.e. retention of the prosthesis over 5.75 years of follow-up) was 83%, but was 89% for first revisions and 73% for re-revisions [hazard ratio = 2.9, 95% confidence interval (CI) 1.2–7.4, P = 0.023]. Reimplantation microbiology was frequently positive (14%), but did not predict outcome (hazard ratio = 1.3, 95% CI 0.4–3.7, P = 0.6). Furthermore, most unplanned debridements following the first stage were carried out before antibiotics were stopped (25 versus 2 debridements).

Conclusions

We did not identify evidence supporting the use of an antibiotic-free period before reimplantation and routine reimplantation microbiology. Re-revision was associated with a significantly worse outcome.

A randomized controlled trial evaluating a topical treatment for chemotherapy-induced neuropathy: NCCTG trial N06CA

9531

Background: Chemotherapy induced peripheral neuropathy (CIPN) is a prevalent dose limiting toxicity for several important cancer treatment agents. CIPN can impair function and cause distress. There are no proven pharmacologic treatments for established CIPN currently. This double blind randomized placebo controlled trial evaluated a compounded topical gel for this problem. The novelty of this treatment is that it might incorporate several agents with different mechanisms of action to provide relief locally without negative systemic effects. Methods: Patients with CIPN (rated ≥4 out of 10) for at least one month, related to previous and/or concurrent exposure to neurotoxic agents, were randomized to baclofen 10 mg, amitriptyline HCL 40 mg and ketamine 20 mg in a pluronic lecithin organogel (BAK-PLO) vs placebo (PLO) to determine its effect on numbness, tingling, pain, and motor function. Exclusion criteria included other causes and/or current treatment for peripheral neuropathy. The primary endpoint was the baseline adjusted sensory subscale of the EORTC QLQ-CIPN20, at 4 weeks. Results: Between February and May 2008, 208 patients were enrolled onto this trial. Four week data are shown in the table below, higher numbers being better. The percentage of patients that had improvements of at least 10, on a 100 point scale, in the motor subscale was statistically significantly higher in the BAK-PLO arm, p=.04. There were no unwanted toxicities associated with the BAK-PLO that were significantly different from placebo and no evidence of CNS or systemic toxicity. Conclusions: Topical treatment with BAK-PLO appears to moderately improve symptoms of CIPN. This topical gel was well tolerated without systemic side effects.

[Table: see text]

No significant financial relationships to disclose.

Healthcare issues of detainees in police custody in London, UK

Little is known about the general healthcare needs of detainees in police custody. The aims of this study were to: determine the level of general health issues, diseases and/or pathology for detainees in police custody, and to determine how well those general health issues, diseases and/or pathology are being managed. This was done by a detailed analysis of healthcare issues of a cohort of detainees and reviewing intended and prescribed medication needs with current medication availability. In August 2007, a prospective detailed, anonymised, structured questionnaire survey was undertaken of 201 detainees in police custody in London, UK. Of these 83.6% consented to participate in the study. 85.1% of subjects were male; mean age was 33.9 years; 70.8% had English as a first language; 13.7% were of no fixed abode; 70.2% were registered with a general practitioner (primary care physician); 25% were already in contact with other healthcare teams; 7.1% had previously been sectioned under the Mental Health Act 1983; 16.7% had previously intentionally self-injured; 33.9% were dependent on heroin, 33.9% on crack cocaine; 25% on alcohol, 16.6% on benzodiazepines and 63.1% on cigarettes. 56% of subjects had active medical conditions; of those with active medical conditions 74% were prescribed medication for those medical conditions; only 3/70 had their medication available. 28/70 were not taking medication regularly, and many were not taking it at all. Three subjects who had deep vein thromboses were not taking their prescribed anticoagulants and six subjects with severe mental health issues were not taking their anti-psychotic medication. Mental health issues and depression predominated, but there was a very large range of mixed diseases and pathology. Asthma, epilepsy, diabetes, deep vein thrombosis, pulmonary embolism, hepatitis, and hypertension were all represented. The study has achieved its aims and has also shown that--in part because of the chaotic lifestyle of many detainees--appropriate care was not being rendered, thereby, putting both detainee, and potentially others coming into contact with them, at risk.

Chick embryo lethal orphan virus can be polymer-coated and retargeted to infect mammalian cells

Non-human adenovirus vectors have attractive immunological properties for gene therapy but are frequently restricted by inefficient transduction of human target cells. Using chicken embryo lethal orphan (CELO) virus, we employed a nongenetic mechanism of polymer coating and retargeting with basic fibroblast growth factor (bFGF-pc-CELOluc), a strategy that permits efficient tropism modification of human adenovirus. bFGF-pc-CELOluc showed efficient uptake and transgene expression in chick embryo fibroblasts (CEF), and increased levels of binding and internalization in a variety of human cell lines. Transgene expression was also greater than unmodified CELOluc in PC-3 human prostate cells, although the specific activity (RLU per internalized viral genome) was decreased. In CEF, the specific activity of bFGF-pc-CELOluc was considerably higher than in the human prostate cell line PC-3. Retargeted virus was fully resistant to inhibition by human serum with known adenovirus-neutralizing activity in vitro, while in mice CELOluc was cleared less rapidly from the blood than Adluc following i.v. administration in the presence of adenovirus neutralizing serum. Polymer coating and retargeting with bFGF further reduced rates of clearance for both viruses, suggesting protection against both neutralizing and opsonizing factors. The data indicate that CELO virus may be retargeted to infect human cells via alternative, potentially disease-specific, receptors and resist the effects of pre-existing humoral immunity.

Radionuclides in fruit systems: a review of experimental studies

Existing information on processes and parameters analysed in experimental studies on fruits was reviewed at the inception of the activities of the IAEA BIOMASS Fruits Working Group. Additional information on experimental studies, collected during the activities of the Group and not included in the Review, is presented and discussed in this paper. Studies on deposition of (14)CO2, CO(35)S and (3)H2O in the gas phase to apple, raspberry, strawberry and blackcurrant have filled gaps in knowledge of uptake of gaseous pollutants in fruit plants, quantifying processes of deposition, translocation and carry-over between seasons. Measurements over a period of six years on vine plants contaminated via leaves and soil by dry deposition of 137Cs and 90Sr have improved knowledge of the processes of direct deposition to fruit, translocation and carry-over of radionuclides from year to year. Additional information is given on soil to fruit transfer of U, Th and Pb for apple and mandarin grown under intensive agricultural conditions.

Modelling and experimental studies on the transfer of radionuclides to fruit

Although fruit is an important component of the diet, the extent to which it contributes to radiological exposure remains unclear, partially as a consequence of uncertainties in models and data used to assess transfer of radionuclides in the food chain. A Fruits Working Group operated as part of the IAEA BIOMASS (BIOsphere Modelling and ASSessment) programme from 1997 to 2000, with the aim of improving the robustness of the models that are used for radiological assessment. The Group completed a number of modelling and experimental activities including: (i) a review of experimental, field and modelling information on the transfer of radionuclides to fruit; (ii) discussion of recently completed or ongoing experimental studies; (iii) development of a database on the transfer of radionuclides to fruit; (iv) development of a conceptual model for fruit and (v) two model intercomparison studies and a model validation study. The Group achieved significant advances in understanding the processes involved in transfer of radionuclides to fruit. The work demonstrated that further experimental and modelling studies are required to ensure that the current generation of models can be applied to a wide range of scenarios.

Crystal structure of an aldehyde reductase Y50F mutant-NADP complex and its implications for substrate binding

Pig aldehyde reductase containing the active site mutation tyrosine(50) to phenylalanine has been crystallized in the presence of the cofactor NADP(H) to a resolution of 2.2 A. This structure clearly shows loss of the tyrosine hydroxyl group and no other significant perturbations compared with previously determined structures. The mutant binds cofactor (both oxidized and reduced) more tightly than the wild-type enzyme but shows a complete lack of binding of the aldehyde reductase inhibitor barbitone, as determined by fluorescence titrations. Numerous attempts at preparing a ternary complex with a range of small aldehyde substrates were unsuccessful. This result, in addition to the inability of the mutant protein to bind the inhibitor, provides strong evidence for the proposal that the tyrosine hydroxyl group is essential for substrate binding in addition to catalysis.

Molecular basis for immunoglobulin M specificity to epitopes in Cryptococcus neoformans polysaccharide that elicit protective and nonprotective antibodies

The protective efficacy of antibodies (Abs) to Cryptococcus neoformans glucuronoxylomannan (GXM) is dependent on Ab fine specificity. Two clonally related immunoglobulin M monoclonal Abs (MAbs) (12A1 and 13F1) differ in fine specificity and protective efficacy, presumably due to variable (V)-region sequence differences resulting from somatic mutations. MAb 12A1 is protective and produces annular immunofluorescence (IF) on serotype D C. neoformans, while MAb 13F1 is not protective and produces punctate IF. To determine the Ab molecular determinants responsible for the IF pattern, site-directed mutagenesis of the MAb 12A1 heavy-chain V region (V(H)) was followed by serological and functional studies of the various mutants. Changing two selected amino acids in the 12A1 V(H) binding cavity to the corresponding residues in the 13F1 V(H) altered the IF pattern from annular to punctate, reduced opsonic efficacy, and abolished recognition by an anti-idiotypic Ab. Analysis of the binding of the various mutants to peptide mimetics revealed that different amino acids were responsible for GXM binding and peptide specificity. The results suggest that V-region motifs associated with annular binding and opsonic activity may be predictive of Ab efficacy against C. neoformans. This has important implications for immunotherapy and vaccine design that are reinforced by the finding that GXM and peptide reactivities are determined by different amino acid residues.

Access to genitourinary medicine clinics in the United Kingdom

OBJECTIVES

To assess the variability in time taken for a patient to be seen in a genitourinary (GUM) clinic in the United Kingdom having contacted that clinic by telephone and compare this with GUM physicians' expectations.

METHODS

A postal questionnaire was sent to lead GUM physicians asking when they thought patients with two specific clinical scenarios would be seen in their clinics. Following this, healthcare personnel contacted individual units posing as patients with the same clinical scenarios and asked to be seen as soon as possible.

RESULTS

202/258 (78%) lead clinicians responded to the postal questionnaire. All clinics claimed to have procedures allowing patients with acute symptoms to be assessed urgently and estimated that such patients would be seen within 48 hours of the initial telephone contact. In 243 of 311 (78%) clinic contacts, the patient was invited to attend the clinic within 48 hours. For the remaining 68 contacts (22%) the patient could not be accommodated within 48 hours and, of these, 49 could not be seen for more than 1 week.

CONCLUSIONS

No clinician estimated that patients with acute severe symptoms would be seen more than 48 hours after the initial telephone contact, but in reality, for 22% of the patient contacts this was the case. This study may well underestimate the difficulties the general public may have in accessing GUM services. We hypothesise that this situation could be ameliorated by establishing process standards and addressing issues of resource allocation.

Signal peptidase and oligosaccharyltransferase interact in a sequential and dependent manner within the endoplasmic reticulum

We demonstrate that the signal peptides of prepro-alpha-factor and preinvertase must be cleaved before Asn-X-Ser/Thr acceptor tripeptides located near the signal peptides of these precursors can be efficiently glycosylated within the endoplasmic reticulum of the yeast Saccharomyces cerevisiae. The data support a model whereby the interaction of a signal peptide with the membrane prevents an acceptor tripeptide juxtaposed to the signal peptide from accessing the oligosaccharyltransferase active site until the signal peptide is cleaved.

Foods found in the wild around nuclear sites: an evaluation of radiological impact

Habit surveys were carried out around four licensed nuclear sites to identify people who collect foodstuffs from the wild (so-called 'free foods'). In total, around 800 collectors were readily identified, most of whom collected more than one free food. The data indicated that estimates of higher than average doses could reasonably be based on the three foodstuffs of most importance. Foods were selected for further study on the basis of either the number of collectors or the amount consumed. The radionuclides of interest were identified using published information on the discharges from each site. The resultant average and higher than average doses were estimated using the site-specific habit data. For all sites, doses from the consumption of free foods were low and of no radiological importance. Assessments based solely on data for cultivated foods would not therefore have underestimated radiological impact significantly. However, given the wide utilisation of free foods found in this study, for rigorous assessments it would be prudent to take account of the consumption of foods from the wild.

The effect of storage and processing on radionuclide content of fruit

After harvesting, the activity content of fruits may still be affected by the manner in which they are treated. Long storage times will reduce the activity contents of short-lived radionuclides; preparation and/or processing may cause activity to be physically removed. This paper presents the results of a review of the available literature on these effects. Data are scarce for both storage and processing, the majority of information on the latter being for 137Cs and 90Sr. For cautious general assessments, it should be assumed that there is no delay and that no activity is lost on processing, especially if the fruits can be eaten raw. However, individual cases may require specific data if available. The use of storage of processing as specific counter-measures to reduce activity concentrations in fruits may not be acceptable to the consumer, especially where alternative, non-contaminated, foodstuffs are readily available.

Conformational changes in the PBX homeodomain and C-terminal extension upon binding DNA and HOX-derived YPWM peptides

PBX is a member of the three amino acid loop extension (TALE) class of homeodomains. PBX binds DNA cooperatively with HOX homeodomain proteins that contain a conserved YPWM motif. The amino acids immediately C-terminal to the PBX homeodomain increase the affinity of the homeodomain for its DNA site and HOX proteins. We have determined the structure of the free PBX homeodomain using NMR spectroscopy. Both the PBX homeodomain and the extended PBX homeodomain make identical contacts with a 5'-TGAT-3' DNA site and a YPWM peptide. A fourth alpha-helix, which forms upon binding to DNA, stabilizes the extended PBX structure. Variations in DNA sequence selectivity of heterodimeric PBX-HOX complexes depend on the HOX partner; however, a comparison of five different HOX-derived YPWM peptides showed that each bound to PBX in the same way, differing only in the strength of the association.

Mutational analysis of MAdCAM-1/alpha4beta7 interactions reveals significant binding determinants in both the first and second immunuglobulin domains

The selective emigration of blood born leukocytes into tissues is mediated, in part by interactions of Ig-like cell adhesion molecules (IgCAMs) expressed on vascular endothelium and their cognate ligands, the leukocyte integrins. Within mucosal lymphoid tissues and gastrointestinal sites the mucosal vascular addressin. MAdCAM-1 is the predominant IgCAM, mediating specific lymphocyte homing via interactions with its ligand on lymphocytes, the integrin alpha4beta7. Previous studies have shown that an essential binding motif resides in the first Ig domain of all IgCAMs, containing an acidic residue (D or E) preceded by an aliphatic residue (L or I) that resides in strand C or the CD loop. However, domain swap experiments with MAdCAM-1 and VCAM-1 have shown a requirement for both Ig domains 1 and 2 for efficient integrin binding. We describe the use of chimeric MAdCAM-1/VCAM-1 receptors and point mutations in MAdCAM-1 to define other sites that are required for binding to the integrin alpha4beta7. We find that, in addition to critical CD loop residues, other regions in both domain one and two contribute to MAdCAM-1/alpha4beta7 interactions, including a buried arginine residue in the F strand of domain one and several acidic residues in a highly extended DE ribbon in domain 2. These mutations, when placed in the recently solved crystal structure of human MAdCAM-1 give insight into the integrin binding preference of this unique receptor.

Signal peptides having standard and nonstandard cleavage sites can be processed by Imp1p of the mitochondrial inner membrane protease

We have performed a site-directed mutagenesis study showing that residues comprising the type I signal peptidase signature in the two catalytic subunits of the yeast inner membrane protease, Imp1p and Imp2p, are functionally important, consistent with the idea that these subunits contain a serine/lysine catalytic dyad. Previous studies have shown that Imp1p cleaves signal peptides having asparagine at the -1 position, which deviates from the typical signal peptide possessing a small uncharged amino acid at this position. To determine whether asparagine is responsible for the nonoverlapping substrate specificities exhibited by the inner membrane protease subunits, we have substituted asparagine with 19 amino acids in the Imp1p substrate i-cytochrome (cyt) b(2). The resulting signal peptides containing alanine, serine, cysteine, leucine, and methionine can be cleaved efficiently by Imp1p. The remaining mutant signal peptides are cleaved inefficiently or not at all. Surprisingly, none of the amino acid changes results in the recognition of i-cyt b(2) by Imp2p, whose natural substrate, i-cyt c(1), has alanine at the -1 position. The data demonstrate that (i) although the -1 residue is important in substrates recognized by Imp1p, signal peptides having standard and nonstandard cleavage sites can be processed by Imp1p, and (ii) a -1 asparagine does not govern the substrate specificity of the inner membrane protease subunits.