Laser-guided lumbar medial branch kryorhizotomy

The authors describe a modification of the medial branch kryorhizotomy technique for the treatment of lumbar facet joint syndrome using a fluoroscopy-based laser-guided method. A total of 32 patients suffering from lumbar facet joint syndrome confirmed by positive medial nerve block underwent conventional or laser-guided kryorhizotomy. The procedural time (20.6 +/- 1.0 vs 16.3 +/- 0.9 minutes, p < 0.01), fluoroscopy time (54.1 +/- 3.5 vs 28.2 +/- 2.4 seconds, p < 0.01), radiation dose (407.5 +/- 32.0 vs 224.1 +/- 20.3 cGy/cm(2), p < 0.01), and patient discomfort during the procedure (7.1 +/- 0.4 vs 5.2 +/- 0.4 on the visual analog scale, p < 0.01) were significantly reduced in the laser-guided group. There was a tendency for a better positioning accuracy when the laser guidance method was used (3.0 +/- 0.3 vs 2.2 +/- 0.3 mm of deviation from the target points, p > 0.05). No difference in the outcome was observed between the 2 groups of patients (visual analog scale score 3.5 +/- 0.2 vs 3.3 +/- 0.3, p > 0.05). This improved minimally invasive surgical technique offers advantages to conventional fluoroscopy-based kryorhizotomy.

Characterisation of extreme winter precipitation in Mediterranean coastal sites and associated anomalous atmospheric circulation patterns

We present an analysis of daily extreme precipitation events for the extended winter season (October–March) at 20 Mediterranean coastal sites covering the period 1950–2006. The heavy tailed behaviour of precipitation extremes and estimated return levels, including associated uncertainties, are derived applying a procedure based on the Generalized Pareto Distribution, in combination with recently developed methods. Precipitation extremes have an important contribution to make seasonal totals (approximately 60% for all series). Three stations (one in the western Mediterranean and the others in the eastern basin) have a 5-year return level above 100 mm, while the lowest value (estimated for two Italian series) is equal to 58 mm. As for the 50-year return level, an Italian station (Genoa) has the highest value of 264 mm, while the other values range from 82 to 200 mm. Furthermore, six series (from stations located in France, Italy, Greece, and Cyprus) show a significant negative tendency in the probability of observing an extreme event. The relationship between extreme precipitation events and the large scale atmospheric circulation at the upper, mid and low troposphere is investigated by using NCEP/NCAR reanalysis data. A 2-step classification procedure identifies three significant anomaly patterns both for the western-central and eastern part of the Mediterranean basin. In the western Mediterranean, the anomalous southwesterly surface to mid-tropospheric flow is connected with enhanced moisture transport from the Atlantic. During ≥5-year return level events, the subtropical jet stream axis is aligned with the African coastline and interacts with the eddy-driven jet stream. This is connected with enhanced large scale ascending motions, instability and leads to the development of severe precipitation events. For the eastern Mediterranean extreme precipitation events, the identified anomaly patterns suggest warm air advection connected with anomalous ascent motions and an increase of the low- to mid-tropospheric moisture. Furthermore, the jet stream position (during ≥5-year return level events) supports the eastern basin being in a divergence area, where ascent motions are favoured. Our results contribute to an improved understanding of daily precipitation extremes in the cold season and associated large scale atmospheric features.

Delayed coverage in malapposed and side-branch struts with respect to well-apposed struts in drug-eluting stents: in vivo assessment with optical coherence tomography

Background—Pathology studies on fatal cases of very late stent thrombosis have described incomplete neointimal coverage as common substrate, in some cases appearing at side-branch struts. Intravascular ultrasound studies have described the association between incomplete stent apposition (ISA) and stent thrombosis, but the mechanism explaining this association remains unclear. Whether the neointimal coverage of nonapposed side-branch and ISA struts is delayed with respect to well-apposed struts is unknown. Methods and Results—Optical coherence tomography studies from 178 stents implanted in 99 patients from 2 randomized trials were analyzed at 9 to 13 months of follow-up. The sample included 38 sirolimus-eluting, 33 biolimus-eluting, 57 everolimus-eluting, and 50 zotarolimus-eluting stents. Optical coherence tomography coverage of nonapposed side-branch and ISA struts was compared with well-apposed struts of the same stent by statistical pooled analysis with a random-effects model. A total of 34 120 struts were analyzed. The risk ratio of delayed coverage was 9.00 (95% confidence interval, 6.58 to 12.32) for nonapposed side-branch versus well-apposed struts, 9.10 (95% confidence interval, 7.34 to 11.28) for ISA versus well-apposed struts, and 1.73 (95% confidence interval, 1.34 to 2.23) for ISA versus nonapposed side-branch struts. Heterogeneity of the effect was observed in the comparison of ISA versus well-apposed struts (H=1.27; I2=38.40) but not in the other comparisons. Conclusions—Coverage of ISA and nonapposed side-branch struts is delayed with respect to well-apposed struts in drug-eluting stents, as assessed by optical coherence tomography.

Comparative transcriptomics of extreme phenotypes of human HIV-1 infection and SIV infection in sooty mangabey and rhesus macaque

High levels of HIV-1 replication during the chronic phase of infection usually correlate with rapid progression to severe immunodeficiency. However, a minority of highly viremic individuals remains asymptomatic and maintains high CD4⁺ T cell counts. This tolerant profile is poorly understood and reminiscent of the widely studied nonprogressive disease model of SIV infection in natural hosts. Here, we identify transcriptome differences between rapid progressors (RPs) and viremic nonprogressors (VNPs) and highlight several genes relevant for the understanding of HIV-1-induced immunosuppression. RPs were characterized by a specific transcriptome profile of CD4⁺ and CD8⁺ T cells similar to that observed in pathogenic SIV-infected rhesus macaques. In contrast, VNPs exhibited lower expression of interferon-stimulated genes and shared a common gene regulation profile with nonpathogenic SIV-infected sooty mangabeys. A short list of genes associated with VNP, including CASP1, CD38, LAG3, TNFSF13B, SOCS1, and EEF1D, showed significant correlation with time to disease progression when evaluated in an independent set of CD4⁺ T cell expression data. This work characterizes 2 minimally studied clinical patterns of progression to AIDS, whose analysis may inform our understanding of HIV pathogenesis.

Radiation doses along selected flight profiles during two extreme solar cosmic ray events

The radiation dose rates at flight altitudes may be hazardously increased during solar cosmic ray events. Within the scope of this paper we investigate the total accumulated radiation doses, i.e. the contribution of galactic and solar cosmic rays, during the two extreme solar cosmic ray events on 29 September 1989 and on 20 January 2005 along selected flight profiles. In addition, the paper discusses the consequences of possible solar cosmic ray flux approximations on the results of the radiation dose computations.