How does susceptibility prevalence impact on the performance of disk diffusion susceptibility testing?

Antimicrobial disk diffusion susceptibility testing, devoted in a clinical context to predicting whether an antibiotic regimen will be effective, should be evaluated through predictive values. This approach implies that the susceptibility prevalence (frequency of susceptible, intermediate, and resistant isolates) affects the predictive value of a result. We quantified the influence of the susceptibility prevalence variation on the disk diffusion method performance through a modeling approach. Simulations based on a resampling procedure from two distinct minimum inhibitory concentration/diameter data sets were performed. Experimental variability on minimum inhibitory concentration and diameters was taken into account in the simulations. Results show that the susceptibility prevalence impact depends on the antibiotic and may be significant when prevalence variation is high enough. Consequences of these results on zone diameter breakpoint determination policy are discussed. This implies that the following should be done: (i) consider more rigorously the susceptibility prevalence in studies dealing with zone diameter breakpoint determination and performance evaluation, (ii) re-evaluate disk diffusion breakpoint consistency when the weight of prevalence variation is noteworthy, (iii) estimate consequences of a breakpoint international consensus on prediction quality and appropriate patient management.     

Minimization of maintenance immunosuppressive therapy after renal transplantation comparing cyclosporine A/azathioprine or cyclosporine A/mycophenolate mofetil bitherapy to cyclosporine A monotherapy: a 10‐year postrandomization follow‐up study

Long‐term outcomes in renal transplant recipients withdrawn from steroid and submitted to further minimization of immunosuppressive regimen after 1 year are lacking. In this multicenter study, 204 low immunological risk kidney transplant recipients were randomized 14.2 ± 3.7 months post‐transplantation to receive either cyclosporine A (CsA) + azathioprine (AZA; n = 53), CsA + mycophenolate mofetil (MMF; n = 53), or CsA monotherapy (n = 98). At 3 years postrandomization, the occurrence of biopsy for graft dysfunction was similar in bitherapy and monotherapy groups (21/106 vs. 26/98; P = 0.25). At 10 years postrandomization, patients’ survival was 100%, 94.2%, and 95.8% (P = 0.25), and death‐censored graft survival was 94.9%, 94.7%, and 95.2% (P = 0.34) in AZA, MMF, and CsA groups, respectively. Mean estimated glomerular filtration rate was 70.4 ± 31.1, 60.1 ± 22.2, and 60.1 ± 19.0 ml/min/1.73 m², respectively (P = 0.16). The incidence of biopsy‐proven acute rejection was 1.4%/year in the whole cohort. None of the patients developed polyomavirus‐associated nephropathy. The main cause of graft loss (n = 12) was chronic antibody‐mediated rejection (n = 6). De novo donor‐specific antibodies were detected in 13% of AZA‐, 21% of MMF‐, and 14% of CsA‐treated patients (P = 0.29). CsA monotherapy after 1 year is safe and associated with prolonged graft survival in well‐selected renal transplant recipient ( ClinicalTrials.gov number: 980654).     

A retrospective comparison of two vaginal mesh kits in the management of anterior and apical vaginal prolapse: long-term results for apical fixation and quality of life

Introduction and hypothesis

To compare apical correction in stage ≥3 cystocele between two mesh kits.

Methods

This was a retrospective, nonrandomized study that compared two groups matched on anterior/apical POP-Q stage: 84 received Elevate Ant? single-incision mesh (Elevate Ant group) and 42 Perigee? transvaginal mesh (Perigee group). Follow-up at 1 and 2 years comprised objective (POP-Q) and subjective (PFDI-20, PFIQ-7, PISQ-12) assessments. The primary endpoint was objective success: 2-year apical POP-Q stage ≤1. Secondary endpoints were anterior POP-Q stage, subjective results and complications.

Results

Groups were comparable in terms of age (66.6 and 64.7 years, respectively; p?=?0.19), BMI (both 25.4 kg/m²; p?=?0.93), and history of hysterectomy (7.2 % and 14.3 %; p?=?0.21) or prolapse surgery (12 % and 14.3 %; p?=?0.72). Operative time was shorter in the Elevate Ant group (54.1 vs. 62.5 min; p?=?0.048), and the 2-year objective apical success rate was higher (92.9 % vs. 66.7 %; p?<?0.0001), with better point C correction (?5 vs. ?3.8; p?=?0.006). Function improved in both groups, with significantly better PFIQ-7 (p?=?0.03) and PFDI-20 (p?=?0.02) scores in the Elevate Ant group at 2 years. Vaginal exposure was not seen in the Elevate Ant group but occurred in two patients in the Perigee group (p?=?0.33). Factors associated with success were age >65 years (OR 7.16, 95 % CI 1.83?–?27.97) and treatment with Elevate Ant mesh (OR 10.16, 95 % CI 2.78?–?37.14). Postoperative stress urinary incontinence rate was greater with the Elevate Ant group (29.8 % and 16.7 %; p?=?0.11).

Conclusions

The use of the Elevate Ant mesh was associated with significantly better apical correction at 2 years. Function improved in both groups, but with a significantly better PFDI-20 score in the Elevate Ant group at 1 and 2 years. The postoperative stress urinary incontinence rate, however, tended to be greater in the Elevate Ant group. The results need confirming with longer follow-up of these cohorts and in randomized studies.

     

Static and dynamic compression application and removal on the intervertebral discs of growing rats

Fusionless implants are used to correct pediatric progressive spinal deformities, most of them spanning the intervertebral disc. This study aimed at investigating the effects of in vivo static versus dynamic compression application and removal on discs of growing rats. A microloading device applied compression. 48 immature rats (28 d.o.) were divided into two groups (43d, 53d). Each group included four subgroups: control (no surgery), sham (device installed without loading), static (0.2 MPa) and dynamic compressions (0.2 MPa ± 30% with 0.1 Hz). In 43d subgroups, compression was applied for 15 days. In 53d subgroups, compression was followed by 10 days without loading. Disc heights, nucleus/annulus volumetric proportions and nucleus proteoglycan contents were analyzed using one‐way ANOVA and post‐hoc Tukey comparisons (p < 0.05). Disc heights of 43d and 53d static and dynamic loading rats were lower than shams (p < 0.05). Volumetric proportions remained similar. At 43d, nucleus proteoglycan contents increased in both static and dynamic loading rats. However, at 53d, static loading rats had lower proteoglycan content than dynamic loading rats (p < 0.05). Disc structure is altered following static compression removal, but nucleus proteoglycan content remaining elevated in dynamic group. Dynamic fusionless implants would better preserve disc integrity. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:290–298, 2016.     

CD4 regulation in human lymphoid non-T-cells: a role for the silencer element

In humans, the CD4 molecule is expressed on a subset of T-cells and at various levels on myeloid and lymphoid cells. The mechanisms regulating human CD4 gene expression are yet poorly understood. We speculated that the CD4 silencer, which operates in CD8+ T-cells to repress CD4 expression, could be responsible for CD4 repression in human lymphoid non-T-cells. To test this possibility, we used lentiviral vectors carrying CD4 regulatory sequences, with or without the silencer element, to express an eGFP reporter gene. We observed that (i) in the absence of the silencer element, eGFP expression was detected in CD34+-derived B- and NK-cells that otherwise lacked endogenous CD4 mRNA, indicating active repression of the CD4 regulatory sequences and (ii) the addition of the CD4 silencer could repress eGFP expression in these same cells, as well as in human B-cells generated in vivo in NOD/SCID mice. Collectively, our results suggest that beyond its well-characterized function in T-cells, the CD4 silencer also regulates CD4 gene expression in human lymphoid non-T-cells.     

Fairness in cost‐benefit analysis: A methodology for health technology assessment

We evaluate the introduction of various forms of antihypertensive treatments in France with a distribution‐sensitive cost‐benefit analysis. Compared to traditional cost‐benefit analysis, we implement distributional weighting based on equivalent incomes, a new concept of individual well‐being that does respect individual preferences but is not subjectively welfarist. Individual preferences are estimated on the basis of a contingent valuation question, introduced into a representative survey of the French population. Compared to traditional cost‐effectiveness analysis in health technology assessment, we show that it is feasible to go beyond a narrow evaluation of health outcomes while still fully exploiting the sophistication of medical information. Sensitivity analysis illustrates the relevancy of this richer welfare framework, the importance of the distinction between an ex ante and an ex post approach, and the need to consider distributional effects in a broader institutional setting.     

Understanding bone safety zones during bone marrow aspiration from the iliac crest: the sector rule

Purpose

Should the trocar suddenly lose contact with bone during bone marrow aspiration, it may result in visceral injury. The anatomy of the ilium and the structures adjacent to the iliac bone were studied to determine the danger of breach by a trocar introduced into the iliac crest.

Methods

The authors followed two series of patients, one series to do measurements of distance and angles of the structures at risk to the iliac bone and the other to evaluate the risk of a trocar being directed outside the iliac wing during bone marrow aspiration. The authors also examined 24 pelvices by computed tomography (CT) scans of mature adults (48 iliac crests). Lines dividing the iliac wing into six equal sectors were used to form sectors (e.g. sector 1 anterior, sector 6 posterior). Vascular or neurological structures were considered at risk if they were accessible to the tip of a 10-cm trocar introduced into the iliac crest with a possible deviation of 20° from the plane of the iliac wing on the three-dimensional reconstruction. The authors tracked bone marrow aspiration of six different surgeons and calculated among 120 patients (480 entry points) the number of times the needle lost contact with bone in each sector of aspiration.

Results

The sector system reliably predicted safe and unsafe areas for trocar placement. Among the 480 entry points in the 120 patients, 94 breaches were observed and higher risks were observed in the thinner sectors. The risk was also higher in obese patients and the risk decreased with more experienced surgeons. The trocar could reach the external iliac artery on pelvic CT scans in the four most anterior sectors with a higher frequency in women. Posterior sectors were at risk for sciatic nerve and gluteal vessel damage when the trocar was pushed deeper than 6 cm into the posterior iliac crest. In cadavers, the dissection demonstrated nine vascular or neurological lesions.

Conclusions

Using the sector system, trocars can be directed away from neural and vascular structures and toward zones that are likely to contain larger bone marrow stock.