Superior flow for bridge to life with self-expanding venous cannulas.

BACKGROUND: Recently, a compact cardiopulmonary support (CPS) system designed for quick set-up for example, during emergency cannulation, has been introduced. Traditional rectilinear percutaneous cannulas are standard for remote vascular access with the original design. The present study was designed to assess the potential of performance increase by the introduction of next-generation, self-expanding venous cannulas, which can take advantage of the luminal width of the venous vasculature despite a relatively small access orifice. METHODS: Veno-arterial bypass was established in three bovine experiments (69+/-10 kg). The Lifebridge (Lifebridge GmbH, Munich, Germany) system was connected to the right atrium in a trans-jugular fashion with various venous cannulas; and the oxygenated blood was returned through the carotid artery with a 17 F percutaneous cannula. Two different venous cannulas were studied, and the correlation between the centrifugal pump speed (1500-3900 RPM), flow and the required negative pressure on the venous side was established: (A) Biomedicus 19 F (Medtronic, Tolochenaz, Switzerland); (B) Smart canula 18 F/36 F (Smartcanula LLC, Lausanne, Switzerland). RESULTS: At 1500 RPM, the blood flow was 0.44+/-0.26 l min(-1) for the 19 F rectilinear cannula versus 0.73+/-0.34 l min(-1) for the 18/36 F self-expanding cannula. At 2500 RPM the blood flow was 1.63+/-0.62 l min(-1) for the 19F rectilinear cannula versus 2.13+/-0.34 l min(-1) for the 18/36 F self-expanding cannula. At 3500 RPM, the blood flow was 2.78+/-0.47 l min(-1) for the 19 F rectilinear cannula versus 3.64+/-0.39 l min(-1) for the 18/36 F self-expanding cannula (p<0.01 for 18/36 F vs 19 F). At 1500 RPM, the venous line pressure was 18+/-8 mmHg for the 19F rectilinear cannula versus 19+/-5 mmHg for the 18/36 F self-expanding cannula. At 2500 RPM the venous line pressure accounted for -22+/-32 mmHg for the 19 F rectilinear cannula versus 2+/-5 mmHg for the 18/36 F self-expanding cannula. At 3500 RPM, the venous line pressure was -112+/-42 mmHg for the rectilinear cannula versus 28+/-7 mmHg for the 18/36 F self-expanding cannula (p<0.01 for 18 F/36 F vs 19 F). Conclusions: The negative pressure required to achieve adequate venous drainage with the self-expanding venous cannula accounts for approximately 31% of the pressure necessary with the 19 F rectilinear cannula. In addition, a pump flow of more than 4 l min(-1) can be achieved with the self-expanding design and a well-accepted negative inlet pressure for minimal blood trauma of less than 50 mmHg.

Translation and assembly of HLA-DR antigens in Xenopus oocytes injected with mRNA from a human B-cell line.

HLA-DR antigens are polymorphic cell surface glycoproteins, expressed primarily in B lymphocytes and macrophages, which are thought to play an important role in the immune response. Two polypeptide chains, alpha and beta, are associated at the cell surface, and a third chain associates with alpha and beta intracellularly. RNA isolated from the human B-cell line Raji was injected in Xenopus laevis oocytes. Immunoprecipitates of translation products with several monoclonal antibodies revealed the presence of HLA-DR antigens similar to those synthesized in Raji cells. One monoclonal antibody was able to bind the beta chain after dissociation of the three polypeptide chains with detergent. The presence of all three chains was confirmed by two-dimensional gel electrophoresis. The glycosylation pattern of the three chains was identical to that observed in vivo, as evidenced in studies using tunicamycin, an inhibitor of N-linked glycosylation. The presence of alpha chains assembled with beta chains in equimolar ratio was further demonstrated by amino-terminal sequencing. An RNA fraction enriched for the three mRNAs, encoding alpha, beta, and intracellular chains, was isolated. This translation-assembly system and the availability of monoclonal antibodies make it possible to assay for mRNA encoding specific molecules among the multiple human Ia-like antigens.

An infrared spectral signature of human lymphocyte subpopulations from peripheral blood.

Metastatic melanomas are frequently refractory to most adjuvant therapies such as chemotherapies and radiotherapies. Recently, immunotherapies have shown good results in the treatment of some metastatic melanomas. Immune cell infiltration in the tumor has been associated with successful immunotherapy. More generally, tumor infiltrating lymphocytes (TILs) in the primary tumor and in metastases of melanoma patients have been demonstrated to correlate positively with favorable clinical outcomes. Altogether, these findings suggest the importance of being able to identify, quantify and characterize immune infiltration at the tumor site for a better diagnostic and treatment choice. In this paper, we used Fourier Transform Infrared (FTIR) imaging to identify and quantify different subpopulations of T cells: the cytotoxic T cells (CD8+), the helper T cells (CD4+) and the regulatory T cells (T reg). As a proof of concept, we investigated pure populations isolated from human peripheral blood from 6 healthy donors. These subpopulations were isolated from blood samples by magnetic labeling and purities were assessed by Fluorescence Activated Cell Sorting (FACS). The results presented here show that Fourier Transform Infrared (FTIR) imaging followed by supervised Partial Least Square Discriminant Analysis (PLS-DA) allows an accurate identification of CD4+ T cells and CD8+ T cells (>86%). We then developed a PLS regression allowing the quantification of T reg in a different mix of immune cells (e.g. Peripheral Blood Mononuclear Cells (PBMCs)). Altogether, these results demonstrate the sensitivity of infrared imaging to detect the low biological variability observed in T cell subpopulations.

Power spectral changes of the superimposed M wave during isometric voluntary contractions of increasing strength.

INTRODUCTION: We examined the power spectral changes of the compound muscle action potential (M wave) evoked during isometric contractions of increasing strength. METHODS: Surface electromyography (sEMG) of the vastus lateralis and medialis was recorded from 20 volunteers who performed 4-s step-wise isometric contractions of different intensities. A maximal M wave was elicited by a single stimulus to the femoral nerve and superimposed on the voluntary contractions. The spectral characteristics (Fmean and Fmedian) of sEMG and M-wave signals were calculated. RESULTS: M-wave spectral indicators increased systematically with contraction intensity up to 60% MVC and then leveled off at higher forces. Over the 10-60% MVC range, the increase in spectral indicators was 3 times higher for M waves (36%) than for sEMG (12%). CONCLUSIONS: The consistent increase in M-wave spectral characteristics with force is due to the fact that the number of motor units recruited by the superimposed supramaximal stimulus is approximately stable.

Decreasing Proportion of Recent Infections among Newly Diagnosed HIV-1 Cases in Switzerland, 2008 to 2013 Based on Line-Immunoassay-Based Algorithms.

BACKGROUND: HIV surveillance requires monitoring of new HIV diagnoses and differentiation of incident and older infections. In 2008, Switzerland implemented a system for monitoring incident HIV infections based on the results of a line immunoassay (Inno-Lia) mandatorily conducted for HIV confirmation and type differentiation (HIV-1, HIV-2) of all newly diagnosed patients. Based on this system, we assessed the proportion of incident HIV infection among newly diagnosed cases in Switzerland during 2008-2013. METHODS AND RESULTS: Inno-Lia antibody reaction patterns recorded in anonymous HIV notifications to the federal health authority were classified by 10 published algorithms into incident (up to 12 months) or older infections. Utilizing these data, annual incident infection estimates were obtained in two ways, (i) based on the diagnostic performance of the algorithms and utilizing the relationship 'incident = true incident + false incident', (ii) based on the window-periods of the algorithms and utilizing the relationship 'Prevalence = Incidence x Duration'. From 2008-2013, 3'851 HIV notifications were received. Adult HIV-1 infections amounted to 3'809 cases, and 3'636 of them (95.5%) contained Inno-Lia data. Incident infection totals calculated were similar for the performance- and window-based methods, amounting on average to 1'755 (95% confidence interval, 1588-1923) and 1'790 cases (95% CI, 1679-1900), respectively. More than half of these were among men who had sex with men. Both methods showed a continuous decline of annual incident infections 2008-2013, totaling -59.5% and -50.2%, respectively. The decline of incident infections continued even in 2012, when a 15% increase in HIV notifications had been observed. This increase was entirely due to older infections. Overall declines 2008-2013 were of similar extent among the major transmission groups. CONCLUSIONS: Inno-Lia based incident HIV-1 infection surveillance proved useful and reliable. It represents a free, additional public health benefit of the use of this relatively costly test for HIV confirmation and type differentiation.

Length of the Mitral Isthmus But Not Anatomical Location of Ablation Line Predicts Bidirectional Mitral Isthmus Block in Patients Undergoing Catheter Ablation of Persistent Atrial Fibrillation: A Randomized Controlled Trial.

INTRODUCTION: Mitral isthmus (MI) ablation is an effective option in patients undergoing ablation for persistent atrial fibrillation (AF). Achieving bidirectional conduction block across the MI is challenging, and predictors of MI ablation success remain incompletely understood. We sought to determine the impact of anatomical location of the ablation line on the efficacy of MI ablation. METHODS AND RESULTS: A total of 40 consecutive patients (87% male; 54 ± 10 years) undergoing stepwise AF ablation were included. MI ablation was performed in sinus rhythm. MI ablation was performed from the left inferior PV to either the posterior (group 1) or the anterolateral (group 2) mitral annulus depending on randomization. The length of the MI line (measured with the 3D mapping system) and the amplitude of the EGMs at 3 positions on the MI were measured in each patient. MI block was achieved in 14/19 (74%) patients in group 1 and 15/21 (71%) patients in group 2 (P = NS). Total MI radiofrequency time (18 ± 7 min vs. 17 ± 8 min; P = NS) was similar between groups. Patients with incomplete MI block had a longer MI length (34 ± 6 mm vs. 24 ± 5 mm; P < 0.001), a higher bipolar voltage along the MI (1.75 ± 0.74 mV vs. 1.05 ± 0.69 mV; P < 0.01), and a longer history of continuous AF (19 ± 17 months vs. 10 ± 10 months; P < 0.05). In multivariate analysis, decreased length of the MI was an independent predictor of successful MI block (OR 1.5; 95% CI 1.1-2.1; P < 0.05). CONCLUSIONS: Increased length but not anatomical location of the MI predicts failure to achieve bidirectional MI block during ablation of persistent AF.

Is the Front Line Prepared for the Changing Faces of Patients? Predictors of Cross-Cultural Preparedness Among Clinical Nurses and Resident Physicians in Lausanne, Switzerland.

UNLABELLED: Phenomenon: Assuring quality medical care for all persons requires that healthcare providers understand how sociocultural factors affect a patient's health beliefs/behaviors. Switzerland's changing demographics highlight the importance of provider cross-cultural preparedness for all patients-especially those at risk for social/health precarity. We evaluated healthcare provider cross-cultural preparedness for commonly encountered vulnerable patient profiles. APPROACH: A survey on cross-cultural care was mailed to Lausanne University hospital's "front-line healthcare providers": clinical nurses and resident physicians at our institution. Preparedness items asked "How prepared do you feel to care for ... ?" (referring to example patient profiles) on an ascending 5-point Likert scale. We examined proportions of "4 - well/5 - very well prepared" and the mean composite score for preparedness. We used linear regression to examine the adjusted effect of demographics, work context, cultural-competence training, and cross-cultural care problem awareness, on preparedness. FINDINGS: Of 885 questionnaires, 368 (41.2%) were returned: 124 (33.6%) physicians and 244 (66.4%) nurses. Mean preparedness composite was 3.30 (SD = 0.70), with the lowest proportion of healthcare providers feeling prepared for patients "whose religious beliefs affect treatment" (22%). After adjustment, working in a sensitized department (β = 0.21, p = .01), training on the history/culture of a specific group (β = 0.25, p = .03), and awareness regarding (a) a lack of practical experience caring for diverse populations (β = 0.25, p = .004) and (b) inadequate cross-cultural training (β = 0.18, p = .04) were associated with higher preparedness. Speaking French as a dominant language and physician role (vs. nurse) were negatively associated with preparedness (β = -0.26, p = .01; β = -0.22, p = .01). Insights: The state of cross-cultural care preparedness among Lausanne's front-line healthcare providers leaves room for improvement. Our study points toward institutional strategies to improve preparedness: notably, making sure departments are sensitized to cross-cultural care resources and increasing provider diversity to reflect the changing Swiss demographic.