Propionibacterium acnes: infection beyond the skin

Propionibacterium acnes is a Gram-positive bacterium that forms part of the normal flora of the skin, oral cavity, large intestine, the conjunctiva and the external ear canal. Although primarily recognized for its role in acne, P. acnes is an opportunistic pathogen, causing a range of postoperative and device-related infections. These include infections of the bones and joints, mouth, eye and brain. Device-related infections include those of joint prostheses, shunts and prosthetic heart valves. P. acnes may play a role in other conditions, including inflammation of the prostate leading to cancer, SAPHO (synovitis, acne, pustulosis, hyperostosis, osteitis) syndrome, sarcoidosis and sciatica. If an active role in these conditions is established there are major implications for diagnosis, treatment and protection. Genome sequencing of the organism has provided an insight into the pathogenic potential and virulence of P. acnes.

Preparation and characterization of amino acids-based trimethoprim salts

Trimethoprim (TMP) is a dihydrofolate reductase (DHFR) inhibitor which prevents the conversion of dihydrofolic acid into tetrahydrofolic acid, resulting in the depletion of the latter and leading to bacterial death. Oral bioavailability of TMP is hindered by both its low solubility and low permeability. This study aims to prepare novel salts of TMP using anionic amino acids; aspartic and glutamic acid as counter ions in order to improve solubility and dissolution. TMP salts were prepared by lyophilisation and characterized using FT-IR spectroscopy, proton nuclear magnetic resonance (1HNMR), Differential Scanning Calorimetry (DSC) and Thermogravimetric analysis (TGA). Both the amino acids formed salts with TMP in a 1:1 molar ratio and showed a 280 fold improvement in solubility. Investigation of the microbiological activity of the prepared salts against TMP sensitive Escherichia coli showed that the new salts not only retained antibacterial activity but also exhibited higher zone of inhibition which was attributed to improved physicochemical characters such as higher solubility and dissolution. The results are an important finding that could potentially impact on faster onset of antibacterial activity and reduced therapeutic dose when administered to patients. Studies are underway investigating the effect of ion-pairing TMP with amino acids on the permeability profile of the drug.

Effect of substrate wettability in liquid dielectrophoresis (LDEP) based droplet generation: theoretical analysis and experimental confirmation

The generation of droplets for biological reactions at the microscale can be achieved by many techniques, among which the so-called liquid dielectrophoresis technique (LDEP). This is not a new process, but the parameters influencing actuation voltage still need further insight: size and geometry (electrodes width and gap, dielectric thickness), materials (dielectric constant), liquids (surface tension, dielectric constant, conductivity), working conditions (voltage, frequency) and substrate wettability (contact angle). This large experimental space is firstly reduced using non dimensional numbers and then studied in a systematic way thanks to the design of experiments. The contact angle influence is explained thanks to a new analytical model. To summarize, this paper recalls analytical models used to predict the voltage threshold required to develop a liquid rivulet from a mother drop, taking the contact angle into account and providing a large set of experimental results.

Co-localisation of host plant resistance QTLs affecting the performance and feeding behaviour of the aphid Myzus persicae in the peach tree

The architecture and action of quantitative trait loci (QTL) contributing to plant resistance mechanisms against aphids, the largest group of phloem-feeding insects, are not well understood. Comparative mapping of several components of resistance to the green peach aphid (Myzus persicae) was undertaken in Prunus davidiana, a wild species related to peach. An interspecific F(1) population of Prunus persica var. Summergrand × P. davidiana clone P1908 was scored for resistance (aphid colony development and foliar damage) and 17 aphid feeding behaviour traits monitored by means of the electrical penetration graph technique. Seven resistance QTLs were detected, individually explaining 6.1-43.1% of the phenotypic variation. Consistency was shown over several trials. Nine QTLs affecting aphid feeding behaviour were identified. All resistance QTLs except one co-located with QTLs underlying aphid feeding behaviour. A P. davidiana resistance allele at the major QTL was associated with drastic reductions in phloem sap ingestion by aphids, suggesting a phloem-based resistance mechanism. Resistance was also positively correlated with aphid salivation into sieve elements, suggesting an insect response to restore the appropriate conditions for ingestion after phloem occlusion. No significant QTL was found for traits characterising aphid mouthpart activity in plant tissues other than phloem vessels. Two QTLs with effects on aphid feeding behaviour but without effect on resistance were identified. SSR markers linked to the main QTLs involved in resistance are of potential use in marker-assisted selection for aphid resistance. Linking our results with the recent sequencing of the peach genome may help clarify the physiological resistance mechanisms.

Gene expression patterns in livers of Hispanic patients infected with hepatitis C virus

We report a gene expression study aimed at the identification of genes differentially expressed in the livers of Hispanic patients infected with hepatitis C virus (HCV). Six uninfected controls were compared with 14 HCV(+) patients in which the liver biopsies were obtained at the time of diagnosis. Among the latter, five patients were also analyzed 4 weeks after the onset of standard anti-HCV therapy (pegylated interferon-α + ribavirin). We identified many genes up- or down-regulated by the infection with HCV in the human livers. When these genes were subjected to pathway analysis, several prominent pathways were revealed including many interferon (IFN)-inducible pathways as well as immune cell trafficking, inflammation, anti-microbial responses, and even cancer. We detected expression of many genes that have previously been associated with HCV infection, as well as several novel genes including CD47. The genes induced by HCV infection showed large expression changes, whereas the genes induced by the IFN-α combination therapy were relatively few (including MX2, ORMDL3, GPAM, KOPX18, TMEM56, and HBP1) and they reflected relatively small expression changes. This is the first study to identify changes in gene expression in livers of HCV(+) Hispanic patients and the first to identify genes induced by anti-HCV combination therapy in the human liver.

Abstract 1770: Enavatuzumab (PDL192), a humanized monoclonal antibody to TweakR, displays broad anticancer activity which is dependent on NFκB signaling

TWEAK (TNFSF12) is a multifunctional cytokine that binds to the cell surface receptor TweakR (Fn14, TNFRSR12A). TweakR is overexpressed in many solid tumor types, including cancers of breast, pancreatic, and ovarian origin. The initial functional description of TWEAK described it as a weak inducer of apoptosis in certain cancer cell lines. TWEAK is also known to function in other diverse biological processes such as inflammation, tissue repair, angiogenesis, cell migration, and growth inhibition. The growth inhibitory activity of TWEAK observed in some cancer cell lines and the overexpression of its receptor in cancer led to investigation of targeting TweakR as a therapeutic modality. Enavatuzumab (PDL192), a humanized IgG1 mAb to TweakR, exhibits some of the same functional activities of TWEAK and is currently in clinical investigation for the treatment of solid tumors due to its significant in vitro and in vivo growth inhibitory activity in models of multiple solid tumor types.

The purpose of the current study was to provide insight into the mechanism of action of enavatuzumab and to further our understanding of the biology of TweakR in tumor cell lines. A panel of 106 cancer cell lines was tested for the ability of enavatuzumab to inhibit in vitro cell growth to identify characteristics of response. Of the 106 cell lines tested, 33 cell lines had >25% growth inhibition in response to the drug. Using luciferase transcriptional reporter constructs, it was revealed that the NFκB pathway was activated in response to enavatuzumab treatment in responder cells. Both classical (p50/p65) and non-classical NFκB (p52/RelB) pathways were subsequently shown to be induced by enavatuzumab treatment using Western blot and functional ELISA in responder cell lines. Using Affymetrix™ microarrays, we observed that cell lines sensitive to enavatuzumab had a higher number of transcriptional changes compared with resistant cells and included many genes known to be regulated by NFκB. To confirm a role for NFκB in enavatuzumab-mediated signaling, we inhibited NFκB pathway induction using siRNAs to the individual NFκB subunits p50, p65, p52, and RelB as well as the upstream kinases IKKα and IKKβ. The siRNAs were able to block enavatuzumab's growth inhibitory activity in multiple sensitive cell lines. Further confirmation of the importance of NFκB was obtained using a small molecule inhibitor of IKKα/β (IKK16) which significantly reduced the drug-induced growth inhibition. The finding that NFκB drives the growth inhibitory activity of enavatuzumab is a compelling function for a family of transcription factors that are more frequently associated with cancer growth and survival than inhibition of cell proliferation.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1770. doi:10.1158/1538-7445.AM2011-1770

[Pacemaker, implanted cardiac defibrillator and irradiation: Management proposal in 2010 depending on the type of cardiac stimulator and prognosis and location of cancer]

Ionizing radiation may interfere with electric components of pacemakers or implantable cardioverter-defibrillators. The type, severity and extent of radiation damage to pacemakers, have previously been shown to depend on the total dose and dose rate. Over 300,000 new cancer cases are treated yearly in France, among which 60% are irradiated in the course of their disease. One among 400 of these patients has an implanted pacemaker or defibrillator. The incidence of pacemaker and implanted cardioverter defribillator increases in an ageing population. The oncologic prognosis must be weighted against the cardiologic prognosis in a multidisciplinary and transversal setting. Innovative irradiation techniques and technological sophistications of pacemakers and implantable cardioverter-defibrillators (with the introduction of more radiosensitive complementary metal-oxide-semiconductors since 1970) have potentially changed the tolerance profiles. This review of the literature studied the geometric, dosimetric and radiobiological characteristics of the radiation beams for high energy photons, stereotactic irradiation, protontherapy. Standardized protocols and radiotherapy optimization (particle, treatment fields, energy) are advisable in order to improve patient management during radiotherapy and prolonged monitoring is necessary following radiation therapy. The dose received at the pacemaker/heart should be calculated. The threshold for the cumulated dose to the pacemaker/implantable cardioverter-defibrillator (2 to 5 Gy depending on the brand), the necessity to remove/displace the device based on the dose-volume histogram on dosimetry, as well as the use of lead shielding and magnet are discussed.

On the consistent measurement of attainment and shortfall inequality

In measuring inequality of a bounded variable such as health status, one can focus on attainments or shortfalls. However, rankings of social states by attainment and shortfall inequality do not necessarily mirror one another. We propose a requirement, that attainment inequality and shortfall inequality be measured consistently, and we examine the performance of partial orderings and indices of inequality in this respect. For relative inequality and all currently documented intermediate inequality concepts, the orderings fail our consistency requirement, as do all indices which respect these orderings. However, the absolute inequality partial ordering satisfies consistency. We identify two classes of indices of absolute inequality, one containing rank-independent and the other rank-dependent indices, which measure attainment and shortfall inequality consistently (in fact identically). The only subgroup decomposable inequality index, of any type, which measures attainment and shortfall inequality consistently is the variance. We discuss implications for the study of pure health inequality.

Publication bias in blood and marrow transplantation

Only a small proportion of abstracts lead to full publication. Abstracts with "positive" results are more likely to be published than other abstracts, leading to publication bias. To date, this issue has not been examined in the blood and marrow transplantation (BMT) literature. We hypothesized that because BMT centers are often based at academic centers, the proportion of abstracts leading to publication will be high. All abstracts presented at the Canadian Blood and Marrow Transplant Group biannual meetings in 2002, 2004, and 2006 were reviewed and categorized by study type, funding source, single-center or multicenter study, form of presentation, and positive or negative results, using the authors' definitions. To determine publication, each reference was searched on multiple databases (MEDLINE, EMBASE, Web of Science, and CINAHL) by first, second, and final author names. Two authors performed abstract categorization and searching, and disagreements were resolved by consensus. Of the 141 abstracts reviewed, only 43 were published (30.4%). Twenty-one studies were published from 2002 (36.8%), compared with 12 from 2004 (24.0%) and 10 from 2006 (29.4%) (P = .35). Neither positive results nor the number of involved centers were associated with the likelihood of publication. Clinical studies (retrospective or prospective) were more likely to be published than nonclinical studies (P = .014). Funded studies and oral presentations were more likely to be published (P = .009 and .004, respectively). A low rate of publication is seen in the field of BMT. Studies with clinical outcomes, externally funded studies, and studies presented orally were more likely to be published. However, there was no publication bias in favor of studies with positive results. Publication bias should be evaluated further at larger BMT meetings, and efforts should be made to encourage full publication of scientific abstracts.

'Speaking valve' aspiration in a laryngectomy patient

Tracheo-oesophageal speech using a one-way speaking valve is a common mode of speech rehabilitation for laryngectomy patients. Aspiration of this device can cause significant airway obstruction and pose anaesthetic and surgical challenges during its retrieval. In this case report, we describe our management of a patient who had had a laryngectomy who aspirated his speaking valve through his stoma. Emergency retrieval of the valve was performed, during which difficulties were encountered, first in obtaining an adequate seal for pre-oxygenation, and second in maintaining adequate oxygen saturation. We discuss some innovative techniques that could be used to address these issues.

Abstract B231: Targeting Her2+ ductal breast cancer with PDL192, a novel humanized anti-TweakR monoclonal antibody

TWEAK receptor (TweakR), also known as Fn14, is a cell surface protein and member of the tumor necrosis factor receptor superfamily. TNFRSF family members are appealing therapeutic targets due to their expression and function in tumor cells. The goal of the current study was to examine the potential of TweakR as a therapeutic target in various subtypes of breast cancer by 1) determining expression of TweakR using immunohistochemistry (IHC) and 2) treating cells derived from breast cancer in vitro and in vivo with PDL192, a novel, humanized anti-TweakR mAb. Overexpression of TweakR protein in breast cancer was confirmed by IHC on formalin fixed paraffin embedded (FFPE) tissues. TweakR was elevated in infiltrating tumors when compared with normal adjacent tissues. 30 to 40% of various subtypes of invasive ductal breast cancer samples stained highly for TweakR; however, fewer than 5% of lobular breast cancer samples had high levels of TweakR. In addition, a strong positive correlation of TweakR and Her2 expression was observed, irrespective of ER status. More than 60% of Her2+ invasive ductal cancer exhibited elevated levels of TweakR. Strong TweakR expression was also observed in bone metastasis samples from primary breast cancer but rarely in benign tumors, such as DCIS.

PDL192 inhibited the in vitro growth of various subtypes of TweakR-expressing breast cancer cell lines and this activity was augmented by crosslinking the mAb. In addition, PDL192 significantly inhibited the in vivo growth of a variant of the breast cancer xenograft model MDA-MB231 that exhibits metastatic potential. PDL192 administration exhibited a dose-dependent inhibition of primary tumor growth and lung metastasis and enhanced the anti-tumor activity of several chemotherapy agents currently used to treat breast cancer. These data provide the rationale to evaluate PDL192 as a potential therapy for the treatment of breast cancer. Currently, PDL192 is being tested in a phase I safety study for the treatment of patients with solid tumors.

Citation Information: Mol Cancer Ther 2009;8(12 Suppl):B231.

Prediction of hemodynamic changes towards PEEP titrations at different volemic levels using a minimal cardiovascular model

A cardiovascular system model and parameter identification method have previously been validated for porcine experiments of induced pulmonary embolism and positive end-expiratory pressure (PEEP) titrations, accurately tracking all the main hemodynamic trends. In this research, the model and parameter identification process are further validated by predicting the effect of intervention. An overall population-specific rule linking specific model parameters to increases in PEEP is formulated to predict the hemodynamic effects on arterial pressure, pulmonary artery pressure and stroke volume. Hemodynamic changes are predicted for an increase from 0 to 10 cm H(2)O with median absolute percentage errors less than 7% (systolic pressures) and 13% (stroke volume). For an increase from 10 to 20 cm H(2)O median absolute percentage errors are less than 11% (systolic pressures) and 17% (stroke volume). These results validate the general applicability of such a rule, which is not pig-specific, but holds over for all analyzed pigs. This rule enables physiological simulation and prediction of patient response. Overall, the prediction accuracy achieved represents a further clinical validation of these models, methods and overall approach to cardiovascular diagnosis and therapy guidance.