Reduced oxygen due to high-altitude exposure relates to atrophy in motor-function brain areas.

BACKGROUND AND PURPOSE: At high altitudes barometric pressure is reduced and, thus, less oxygen is inhaled. Reduced oxygen concentration in brain tissue can lead to cerebral damage and neurological and cognitive deficits. The present study was designed to explore the effects of high-altitude exposure using a quantitative MRI technique, voxel-based morphometry. METHODS: We studied nine world-class mountain climbers before (baseline) and after (follow-up) an extremely high-altitude ascent of Everest and K2. We investigated the effects of repeated extremely high-altitude exposures by comparing mountain climbers' scans at baseline with scans of 19 controls. In addition, we measured the effects of a single extremely high-altitude expedition by comparing mountain climbers' scans at baseline and follow-up. RESULTS: A region of reduced white matter density/volume was found in the left pyramidal tract near the primary (BA 4) and supplementary (BA 6) motor cortex when mountain climbers at baseline were compared with controls. Further, when mountain climbers' scans before and after the expedition were compared, a region of reduced grey matter density/volume was found in the left angular gyrus (BA 39). CONCLUSION: These findings suggest that extremely high-altitude exposures may cause subtle white and grey matter changes that mainly affect brain regions involved in motor activity.

[In vivo experimental research in vascular surgery. Methodology and current Italian law]. / La ricerca sperimentale in vivo in chirurgia vascolare. Metodologia ed attuale normativa italiana.

Authors underscore the importance of research in vascular surgery progress and approach some basic aspects on the correct conduction of an experimental research in vascular surgery fields and in particular on synthetic prosthesis of different diameter. Some important aspects of the current Italian law on animal experimentation are shown because they could cause new changes either on methodology or animal selection. Finally some experimental models adopted in the department of experimental surgery of the Rizzoli Orthopaedic Institutes on vascular prosthesis are described.

Failure of thrombolytic therapy to improve long-term vascular patency.

PURPOSE: Few data are available on long-term follow-up of arterial segments subjected to thrombolysis. We reviewed all cases of vascular occlusion treated with urokinase to identify early success and determine the influence of postlysis intervention and the nature of the thrombosed segment (i.e., artery vs graft) on long-term patency. METHODS: Data on 134 cases (58 arteries, 76 grafts) treated with high-dose urokinase infusion in the lower limbs over a 7-year period were analyzed. Limbs were divided into five groups on the basis of therapy after lytic infusion to determine long-term efficacy: group I, success with no additional therapy; group II, percutaneous angioplasty alone; group III, limited surgical procedure (operative angioplasty, jump graft); group IV, extensive procedure (new bypass); and group V, revascularization after lytic failure. Long-term results were assessed by life-table analysis and groups compared by log-rank test (Mantel-Haenszel). RESULTS: Initial patency was established in 87 (64.9%) of 134 cases with 5 deaths (3.7%), 11 amputations (8.2%), and 16 complications (11.9%). Follow-up was available in 68.6% of cases for a mean of 10.9 months. No difference was seen between grafts and native arteries. Patency was analyzed at 6, 12, 18, and 24 months. The 24-month patency rate after lysis alone (group I-25.9%) was inferior (p < 0.05) to results after lysis and any subsequent intervention (groups II, III, and IV). The type of intervention did not influence subsequent patency. Twenty-four-month patency of procedures performed after failed thrombolysis (group V, 41.4%) was not different from those after successful lysis (groups I to IV). Twenty-four-month patency in groups II and III (minor interventions, 62.9%) was not significantly different from that of groups IV and V (major interventions, 53.2%) (p > 0.25). CONCLUSIONS: Operative intervention is required to produce long-term arterial patency, even after successful thrombolysis. No statistically significant benefit of thrombolysis on vascular patency was seen in our series.