Varying proliferative and clonogenic potential in NRAS‐mutated congenital melanocytic nevi according to size

Congenital melanocytic nevi (CMN) are benign proliferations that may be associated with various consequences depending on their size. They are characterized by a specific molecular signature, namely a postzygotic somatic NRAS or BRAF mutation. We have recently reported that large CMN (lCMN), which are classically associated with an increased melanoma risk, harbour cell subpopulations with specific clonogenic and tumorigenic potential. We wished to ascertain whether cells displaying similar properties persisted postnatally in medium CMN (mCMN). Eighteen medium M1, nine large and one giant NRAS‐mutated CMN were prospectively included in the study. Subpopulations of mCMN cells expressed stem cell/progenitor lineage markers such as Sox10, nestin and Oct4, as was the case in lCMN. Nevertheless, conversely to lCMN, mCMN cells with clonogenic properties were rarer. In vitro, approximatively one in 1500 cells isolated from fresh mCMN formed colonies that could be passaged. In vivo, mCMN seemed to harbour cells with less proliferative potential than the larger lesions as lCMN biopsies displayed a threefold expansion compared to mCMN when xenografted in Rag2^?/? mice. Thus, our data revealed variations in clonogenicity and tumorigenic properties in NRAS‐mutated CMN according to size.     

Differences in postablation cardiac MRI scar between radiofrequency and cryoballoon ablation: A DECAAF II subanalysis

Introduction

Pulmonary vein isolation (PVI) using radiofrequency (RF) and cryoballoon (Cryo) ablation are standard approaches for rhythm control in patients with symptomatic atrial fibrillation. Both strategies create scars in the left atrium (LA). There have been few studies investigating the difference in scar formation between patients undergoing RF and Cryo using cardiac magnetic resonance (CMR) imaging.

Methods

The current study is a subanalysis of the control arm of the Delayed-Enhancement MRI Determinant of Successful Catheter Ablation of Atrial Fibrillation study (DECAAF II). The study was a multicenter, randomized, controlled, single-blinded trial that evaluated atrial arrhythmia recurrence (AAR) between PVI alone and PVI plus CMR atrial fibrosis-guided ablation. Preablation CMR and 3- to 6-month postablation CMR were obtained to assess baseline LA fibrosis and scar formation, respectively.

Results

Of the 843 patients randomized in the DECAAF II trial, we analyzed the 408 patients in the primary analysis control arm that received standard PVI. Five patients received combined RF and Cryo ablations, so they were excluded from this subanalysis. Of the 403 patients analyzed, 345 underwent RF and 58 Cryo. The average procedure duration was 146 min for RF and 103 min for Cryo (p = .001). The rate of AAR at ~15 months occurred in 151 (43.8%) patients in the RF group and 28 (48.3%) patients in the Cryo group (p = .62). On 3-month post-CMR, the RF arm had significantly more scar (8.8% vs. 6.4%, p = .001) compared to Cryo. Patients with ≥6.5% LA scar (p < .001) and ≥2.3% LA scar around the PV antra (p = .01) on 3-month post-CMR had less AAR independent of the ablation technique. Cryo caused a greater percentage of right and left pulmonary vein (PV) antral scar (p = .04, p = .02) and less non-PV antral scar (p = .009) compared to RF. On Cox regression, Cryo patients free of AAR had a greater percentage of left PV antral scar (p = .01) and less non-PV antral scar (p = .004) compared to RF free of AAR.

Conclusion

In this subanalysis of the control arm of the DECAAF II trial, we observed that Cryo formed a more significant percentage of PV antral scar and less non-PV antral scar compared to RF. Post ablation LA scar ≥6.5% predicted freedom from AAR, independent of ablation technique. These findings may have prognostic implications in ablation technique selection and freedom from AAR.     

Specific deficits in visual electrophysiology in a mouse model of dominant optic atrophy

Autosomal dominant optic atrophy (ADOA) is a slowly progressive optic neuropathy caused by mutations in the OPA1 gene. OPA1 is ubiquitously expressed and plays a key role in mitochondrial fusion. Heterozygous Opa1 mutant mice (B6; C3-Opa1^Q285STOP), have previously been reported to develop visual defects and optic nerve changes. In this study, in vivo visual electrophysiological testing (ERGs and VEPs) was performed on 11–13 month old B6; C3-Opa1^Q285STOP mice (n = 5) and age/sex matched wildtype littermate controls. Full intensity series were recorded in response to brief (4 ms) single flash stimuli delivered in a Ganzfeld dome under dark- and light-adapted conditions. The major ERG components (a-wave and b-wave) showed no detectable difference from wildtype in the amplitude or implicit time of dark-adapted ERGs across the full intensity range tested. This was also true for the components of the dark-adapted VEP. However, the light-adapted ERG responses revealed a significant reduction in the photopic negative response (PhNR) amplitude in Opa1^+/− animals relative to wildtypes at the brighter intensities tested. Elements of the light-adapted VEP were also abnormal in mutant mice. Overall Opa1^+/− mice display functional deficits in electrophysiology that are consistent with ganglion cell dysfunction. These deficits may correlate with a reduction in the dendritic arborisation of retinal ganglion cells, which has been previously reported to occur at a similar age in the same mutant mouse line (Williams et al., 2010). The functional phenotype we have described in this mouse model may be useful in the robust and accurate assessment of potential treatments for ADOA.     

The effect of fetal neck position on nuchal fold thickness

OBJECTIVE: Our purpose was to determine whether ultrasonographic measurements of nuchal fold thickness are affected by the position of the fetal neck. STUDY DESIGN: Fetal nuchal fold thickness was prospectively measured in 258 women undergoing routine ultrasonography at 15 to 21 completed weeks of gestation. Patients with fetal structural or chromosomal anomalies were excluded. At the time of examination the position of the fetal head was noted as being extended or flexed on the basis of the angle between the spine and the base of the skull. Gestational age was based on menstrual dates or ultrasonographic biometric parameters. Data were tested for normality. Mann-Whitney U test and analysis of covariance were used (significance was considered to be P <.05). Data are presented as median and range. RESULTS: A total of 258 fetuses were examined with 167 (65%) in the flexed and 91 (35%) in the extended neck position. Gestational age was not significantly different between the flexed and extended groups (median, 19.1 weeks; range, 15.5-21.6 weeks; vs median, 19.1 weeks; range, 15.6-22 weeks; P =.23). Nuchal fold thickness was significantly lower in the flexed group than in the extended group (median, 3.5 mm; range, 1.3-6.2 mm; vs median, 3.9 mm; range, 2.2-4.9 mm; P =.0097). Nuchal fold thickness increased significantly with gestational age in both groups. The difference in nuchal fold thickness between the 2 groups persisted even after the increase in nuchal fold thickness was adjusted for with gestational age (P =.002, analysis of covariance). The difference between the 2 groups was higher at earlier gestations. CONCLUSION: Nuchal fold thickness is affected by gestational age and fetal neck position. Correction for these variables may improve the accuracy of nuchal fold thickness measurements in screening for fetal chromosomal anomalies.     

Prognosis value of partial arterial oxygen pressure in patients with septic shock subjected to pre-hospital invasive ventilation

Objective

Mechanical ventilation can help improve the prognosis of septic shock. While adequate delivery of oxygen to the tissue is crucial, hyperoxemia may be deleterious. Invasive out-of-hospital ventilation is often promptly performed in life-threatening emergencies. We propose to determine whether the arterial oxygen pressure (PaO₂) at the intensive care unit (ICU) admission is associated with mortality in patients with septic shock subjected to pre-hospital mechanical ventilation.

Capacitative calcium entry and transient receptor potential canonical 6 expression control human hepatoma cell proliferation

Store-operated calcium entry (SOCE) is the main Ca(2+) influx pathway involved in controlling proliferation of the human hepatoma cell lines Huh-7 and HepG2. However, the molecular nature of the calcium channels involved in this process remains unknown. Huh-7 and HepG2 cells express transient receptor potential canonical 1 (TRPC1) and TRPC6, as well as STIM1 and Orai1, and these 4 channels are the most likely candidates to account for the SOCE in these cells. We generated stable TRPC6-overexpressing or TRPC6-knockdown Huh-7 clones, in which we investigated correlations between the presence of the protein, the rate of cell proliferation, and SOCE amplitude. TRPC6-overexpressing Huh-7 cells proliferated 80% faster than did untransfected cells and their SOCE amplitude was 160% higher. By contrast, proliferation rate was 50% lower and SOCE amplitude 85% lower in TRPC6-knockdown clones than in untransfected cells. OAG (olyl acetyl glycerol)-induced calcium entry was similar in all cells, and small interfering RNA (siRNA) against TRPC1 had no effect on SOCE amplitude, highlighting the relationship among SOCE, TRPC6 and cell proliferation in Huh-7 cells. SOCE amplitude was reduced by STIM1 and Orai1 knockdowns, suggesting possible cooperation between these proteins and TRPC6 in these cells. Endothelial growth factor and hepatocyte growth factor increased TRPC6 expression and SOCE amplitude in Huh-7 cells, and cyclin D1 expression was decreased by STIM1, Orai1, and TRPC6 knockdowns. CONCLUSION: TRPC6 was very weakly expressed in isolated hepatocytes from healthy patients and expressed more strongly in tumoral samples from the liver of a cancer patient, strongly supporting a role for these calcium channels in liver oncogenesis.     

Radiofrequency ablation of hepatocellular carcinoma as a bridge to liver transplantation

Background

Radiofrequency ablation (RFA) of hepatocellular carcinoma (HCC) is widely utilized as a bridge to liver transplant with limited evidence to support efficacy. The purpose of the present study was to measure the effect of RFA on time to drop-off in HCC-listed patients.

Methods

Patients with Milan criteria tumours listed between January 1999 and June 2007 were stratified into RFA (n = 77) and No Treatment groups (n = 93).

Results

The primary effectiveness of RFA was 83% (complete radiographic response). RFA was associated with a longer median wait time to transplant (9.5 vs. 5 months). Tumour-specific drop-off events were equivalent between RFA (21%) and No Treatment (12%) groups (P = 0.11). Controlling for wait time, there was no difference in overall (P = 0.56) or tumour-specific drop-off (P = 0.94). Furthermore, there were no differences in 5-year overall or tumour-free survivals from list date or transplant. Using multivariate analysis, the likelihood of receiving a transplant and patient survivals were associated with tumour characteristics (AFP, tumour number and size) and not with bridge therapy or waiting time.

Discussion

RFA allows patients to be maintained longer on the waiting list without negative consequences on drop-off or survival compared with no treatment. Post-transplant outcomes are affected more by tumour characteristics than RFA or wait time.