125 research outputs found

    A room temperature 19-channel magnetic field mapping device for cardiac signals

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    We present a multichannel cardiac magnetic field imaging system built in Fribourg from optical double-resonance Cs vapor magnetometers. It consists of 25 individual sensors designed to record magnetic field maps of the beating human heart by simultaneous measurements on a grid of 19 points over the chest. The system is operated as an array of second order gradiometers using sophisticated digitally controlled feedback loops.Comment: 3 pages, 3 figures, submitted to Applied Physics Letter

    A large sample study of spin relaxation and magnetometric sensitivity of paraffin-coated Cs vapor cells

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    We have manufactured more than 250 nominally identical paraffin-coated Cs vapor cells (28mm inner diameter bulbs) for multi-channel atomic magnetometer applications. We describe our dedicated cell characterization apparatus. For each cell we have determined the intrinsic longitudinal, Γ 01, and transverse, Γ 02, relaxation rates. Our best cell shows Γ 01/2π≈0.5Hz, and Γ 02/2π≈2Hz. We find a strong correlation of both relaxation rates which we explain in terms of reservoir and spin exchange relaxation. For each cell we have determined the optimal combination of rf and laser powers which yield the highest sensitivity to magnetic field changes. Out of all produced cells, 90% are found to have magnetometric sensitivities in the range of 9to 30fT Hz\sqrt{\mathrm{Hz}} . Noise analysis shows that the magnetometers operated with such cells have a sensitivity close to the fundamental photon shot noise limi

    Satisfaction of patients on chronic haemodialysis and peritoneal dialysis

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    BACKGROUND: In contrast to quality of life, patient satisfaction on chronic haemodialysis (HD) and peritoneal dialysis (PD) has only rarely been studied. PATIENTS AND METHODS: All chronic HD and PD patients of the 19 centres located in western Switzerland were asked to complete a specific questionnaire, assessing dialysis centre characteristics, treatment modalities, and information received before and during dialysis treatment. Comparison between satisfaction with PD and HD was carried out on the patients in the nine centres offering both treatment modalities. RESULTS: Of the 558 questionnaires distributed to chronic HD patients, 455 were returned (response rate 82%). Fifty of 64 PD patients (78%) returned the questionnaire. The two groups were similar in age, gender, and duration of dialysis treatment. Completion rates were >90% for a majority of questions, with the lowest rate for information on sexuality (49% in HD and 54% in PD respectively). The lowest scores were recorded for information received about complications and costs of dialysis, and impact of end-stage kidney disease on sexuality. Satisfaction was lower in anonymous questionnaires. Satisfaction of PD patients was significantly better in 50% of the questions, particularly session tolerance (p<0.001), information about dialysis sessions (p=0.007), and complications (p=0.006). CONCLUSIONS: PD patients were on average more satisfied with their treatment than HD patients. Satisfaction could be improved with more information about potential adverse treatment effects

    A large sample study of spin relaxation and magnetometric sensitivity of paraffin-coated Cs vapor cells

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    We have manufactured more than 250 nominally identical paraffin-coated Cs vapor cells (30 mm diameter bulbs) for multi-channel atomic magnetometer applications. We describe our dedicated cell characterization apparatus. For each cell we have determined the intrinsic longitudinal, \sGamma{01}, and transverse, \sGamma{02}, relaxation rates. Our best cell shows \sGamma{01}/2\pi\approx 0.5 Hz, and \sGamma{02}/2\pi\approx 2 Hz. We find a strong correlation of both relaxation rates which we explain in terms of reservoir and spin exchange relaxation. For each cell we have determined the optimal combination of rf and laser powers which yield the highest sensitivity to magnetic field changes. Out of all produced cells, 90% are found to have magnetometric sensitivities in the range of 9 to 30 fTHz. Noise analysis shows that the magnetometers operated with such cells have a sensitivity close to the fundamental photon shot noise limit

    Quality of life on chronic dialysis: comparison between haemodialysis and peritoneal dialysis

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    BACKGROUND: Quality of life (QOL) assessment in patients on chronic haemodialysis (HD) or peritoneal dialysis (PD) has only rarely been carried out with the generic Euroqol-5D questionnaire. METHODS: All chronic HD and PD patients in the 19 centres of western Switzerland were requested to fill in the validated Euroqol-5D generic QOL questionnaire, assessing health status in five dimensions and on a visual analogue scale, allowing computation of a predicted QOL value, to be compared with the value measured on the visual analogue scale. RESULTS: Of the 558 questionnaires distributed to chronic HD patients, 455 were returned (response rate 82%). Fifty of 64 PD patients (78%) returned the questionnaire. The two groups were similar in age, gender and duration of dialysis treatment. Mean QOL was rated at 60+/-18% for HD and 61+/-19% for PD, for a mean predicted QOL value of 62+/-30 and 58+/-32% respectively. Results of the five dimensions were similar in both groups, except for a greater restriction in usual activities for PD patients (P = 0.007). The highest scores were recorded for self-care, with 71% HD and 74% PD patients reporting no limitation, and the lowest scores for usual activities, with 14% HD and 23% PD patients reporting severe limitation. Experiencing pain/discomfort (for HD and PD) or anxiety/depression (for PD) had the highest impact on QOL. CONCLUSIONS: QOL was equally diminished in HD and PD patients. The questionnaire was well accepted and performed well. Improvement could be achievable in both groups if pain/discomfort and anxiety/depression could be more effectively treated

    Variability in quality of care among dialysis units in western Switzerland

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    BACKGROUND: Quality indicators for dialysis care vary across countries and regions, but regional variability across centres has received little attention. We analysed variations in quality indicators among dialysis facilities in western Switzerland to identify opportunities for improving care for patients with end-stage kidney disease. METHODS: A cross-sectional study of 617 dialysis patients treated at 19 facilities examined the distribution of indicators of quality of care addressing: adequacy of dialysis (Kt/V > or =1.2 for haemodialysis, Kt/V > or =2 for peritoneal dialysis), anaemia control (haemoglobin > or =110 g/l), calcium and phosphate control (product < or =4.4 mmol2/l2), adequate nutrition (serum albumin >35 g/l), hypertension control (pre-dialysis blood pressure <140/90 mmHg) and type of vascular access. Centre quality targets were the following: achievement of quality criteria for 80% of their patients, except 85% for anaemia control and 60% for arterio-venous fistulae. RESULTS: Most centres fulfilled quality targets for dialysis adequacy, but substantial variations existed among centres (haemodialysis, 76%, range 36-100; peritoneal dialysis, 76%, range 33-100). Results were similar for anaemia (77%, range 35-100), calcium x phosphate product (69%, range 29-92), albumin (63%, range 26-95), hypertension control (33%, range 13-54) and arterio-venous fistula (61%, range 49-92). The between-centre variability was significantly greater than would be expected by chance, for all indicators. Dialysis facilities with >40 patients better fulfilled quality targets than university-based centres. Adjustment for patient characteristics did not modify these results. CONCLUSIONS: Substantial variations in quality indicators existed between dialysis centres in western Switzerland, which could not be attributed to different centre policies, or to differences in available measures of patient case mix. These findings indicate opportunities for improvement in dialysis practice which may translate into improved clinical outcomes

    Celecoxib does not appear to affect prosthesis fixation in total knee replacement: A randomized study using radiostereometry in 50 patients

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    Background and purpose After joint replacement, a repair process starts at the interface between bone and cement. If this process is disturbed, the prosthesis may never become rigidly fixed to the bone, leading to migration—and with time, loosening. Cox-2 inhibitors are widely used as postoperative analgesics, and have adverse effects on bone healing. This could tamper prosthesis fixation. We investigated whether celecoxib, a selective Cox-2 inhibitor, increases prosthesis migration in total knee replacement (TKR)

    Targeted Chromosomal Insertion of Large DNA into the Human Genome by a Fiber-Modified High-Capacity Adenovirus-Based Vector System

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    A prominent goal in gene therapy research concerns the development of gene transfer vehicles that can integrate exogenous DNA at specific chromosomal loci to prevent insertional oncogenesis and provide for long-term transgene expression. Adenovirus (Ad) vectors arguably represent the most efficient delivery systems of episomal DNA into eukaryotic cell nuclei. The most advanced recombinant Ads lack all adenoviral genes. This renders these so-called high-capacity (hc) Ad vectors less cytotoxic/immunogenic than those only deleted in early regions and creates space for the insertion of large/multiple transgenes. The versatility of hcAd vectors is been increased by capsid modifications to alter their tropism and by the incorporation into their genomes of sequences promoting chromosomal insertion of exogenous DNA. Adeno-associated virus (AAV) can insert its genome into a specific human locus designated AAVS1. Trans- and cis-acting elements needed for this reaction are the AAV Rep78/68 proteins and Rep78/68-binding sequences, respectively. Here, we describe the generation, characterization and testing of fiber-modified dual hcAd/AAV hybrid vectors (dHVs) containing both these elements. Due to the inhibitory effects of Rep78/68 on Ad-dependent DNA replication, we deployed a recombinase-inducible gene switch to repress Rep68 synthesis during vector rescue and propagation. Flow cytometric analyses revealed that rep68-positive dHVs can be produced similarly well as rep68-negative control vectors. Western blot experiments and immunofluorescence microscopy analyses demonstrated transfer of recombinase-dependent rep68 genes into target cells. Studies in HeLa cells and in the dystrophin-deficient myoblasts from a Duchenne muscular dystrophy (DMD) patient showed that induction of Rep68 synthesis in cells transduced with fiber-modified and rep68-positive dHVs leads to increased stable transduction levels and AAVS1-targeted integration of vector DNA. These results warrant further investigation especially considering the paucity of vector systems allowing permanent phenotypic correction of patient-own cell types with large DNA (e.g. recombinant full-length DMD genes)

    Internal fixation treatments for intertrochanteric fracture: A systematic review and meta-Analysis of randomized evidence

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    The relative effects of internal fixation strategies for intertrochanteric fracture after operation remain uncertain. We conducted a systematic review and meta-Analysis of randomized controlled trials (RCTs) to address this important issue. We searched PubMed, EMBASE and CENTRAL for RCTs that compared different internal fixation implants in patients with intertrochanteric fracture at 6-month follow-up or longer. We ultimately included 43 trials enrolling 6911 patients; most trials were small in sample sizes and events. Their risk of bias was generally unclear due to insufficient reporting. Because of these, no statistically significant differences were present from most of the comparisons across all the outcomes, and no definitive conclusions can be made. However, a number of trials compared two commonly used internal fixation strategies, gamma nail (GN) and sliding hip screw (SHS). There is good evidence suggesting that, compared to SHS, GN may increase the risk of cut out (OR = 1.87, 95% CI, 1.08 to 3.21), re-operation (OR = 1.61, 95% CI, 1.02 to 2.53), intra-operative (OR = 3.14, 95% CI, 1.34 to 7.35) and later fractures (OR = 3.67, 95% CI, 1.37 to 9.83). Future randomized trials or observational studies that are carefully designed and conducted are warranted to establish the effects of alternative internal fixation strategies for intertrochanteric fracture
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