Geodesic Distance Histogram Feature for Video Segmentation

This paper proposes a geodesic-distance-based feature that encodes global information for improved video segmentation algorithms. The feature is a joint histogram of intensity and geodesic distances, where the geodesic distances are computed as the shortest paths between superpixels via their boundaries. We also incorporate adaptive voting weights and spatial pyramid configurations to include spatial information into the geodesic histogram feature and show that this further improves results. The feature is generic and can be used as part of various algorithms. In experiments, we test the geodesic histogram feature by incorporating it into two existing video segmentation frameworks. This leads to significantly better performance in 3D video segmentation benchmarks on two datasets

Quantification and predictors of plasma volume expansion from mannitol treatment

Objective: To determine the effects of acute hypertonic mannitol infusion on intravascular volume expansion and to identify potential predictors of hypervolemia. Design: Measurements of plasma volume and volume regulatory hormones were performed in healthy volunteers before and over 90 min after acute infusion of 20 % mannitol solution in a therapeutic dose of 0.5 g/kg body weight, equalling an average infusion volume of 180 ml. Setting: Clinical research unit in an 800-bed teaching hospital in the eastern part of Switzerland. Participants: Eight normal male volunteers. Measurements and results: Baseline plasma volume was determined by the indocyanine green dye dilution technique. Serial plasma protein measurements were performed after mannitol infusion to calculate intravascular volume changes. Mannitol administration resulted in a plasma expansion that persisted for more than 90 min and peaked at 112 % of the baseline plasma volume 15 min after infusion. Concomitantly, an increase in systolic blood pressure and a fall in plasma sodium concentration occurred. Pharmacokinetic analyses of mannitol distribution and elimination revealed a close relation between plasma volume expansion and mannitol serum concentrations. While renin activity and aldosterone concentrations were suppressed proportionally to the intravascular volume increase, antidiuretic hormone was increased despite notable volume expansion and hyponatremia. Similarly, a rise in atrial natriuretic peptide was detected. Conclusions: Therapeutic doses of hypertonic mannitol cause substantial plasma volume expansion, resulting in increased blood pressure. Plasma volume expansion is related to mannitol serum concentrations and mannitol clearance determines the time required to restore normovolemia. ADH and ANP are potentially aggravating factors of mannitol-induced hyponatremi

Effects of creatine supplementation on muscle weakness in patients with rheumatoid arthritis

Background and objectives. Patients with rheumatoid arthritis (RA) frequently suffer from muscle weakness. Oral administration of creatine has been shown to improve muscle strength in healthy subjects. The objective of this study was to examine the effect of oral creatine supplementation on muscle weakness, disease activity and activities of daily living in patients with RA. Methods. During a period of 3 weeks, 12 patients with RA were treated with creatine monohydrate (20 g/day for 5 days followed by 2 g/day for 16 days). They were examined on entry and at the end of the study. The patients were investigated clinically, blood and urine samples were obtained, muscle biopsies were performed before and after treatment, muscle strength was determined, and self‐administered patient questionnaires were completed. Results. From all patients we were able to obtain full clinical and questionnaire data, while biopsies were taken from 12 patients at the start and from nine patients at the end of the study. Muscle strength, as determined by the muscle strength index, increased in eight of 12 patients. In contrast, physical functional ability and disease activity did not change significantly. The creatine concentration in serum and skeletal muscle increased significantly, while creatine phosphate and total creatine did not increase in skeletal muscle. The skeletal muscle creatine content was associated with muscle strength at baseline but not after administration of creatine. The changes in muscle strength were not associated with the changes in skeletal muscle creatine or creatine phosphate. Conclusion. Although the skeletal muscle creatine content and muscle strength increased with creatine administration in some patients with RA, a clear clinical benefit could not be demonstrated for this treatment when the patients were considered as one grou

Toxicity of statins on rat skeletal muscle mitochondria

Abstract.: We investigated mitochondrial toxicity of four lipophilic stains (cerivastatin, fluvastatin, atorvastatin, simvastatin) and one hydrophilic statin (pravastatin). In L6 cells (rat skeletal muscle cell line), the four lipophilic statins (100μmol/l) induced death in 27-49% of the cells. Pravastatin was not toxic up to 1mmol/l. Cerivastatin, fluvastatin and atorvastatin (100μmol/l) decreased the mitochondrial membrane potential by 49-65%, whereas simvastatin and pravastatin were less toxic. In isolated rat skeletal muscle mitochondria, all statins, except pravastatin, decreased glutamate-driven state 3 respiration and respiratory control ratio. Beta-oxidation was decreased by 88-96% in the presence of 100μmol/l of the lipophilic statins, but only at higher concentrations by pravastatin. Mitochondrial swelling, cytochrome c release and DNA fragmentation was induced in L6 cells by the four lipophilic statins, but not by pravastatin. Lipophilic statins impair the function of skeletal muscle mitochondria, whereas the hydrophilic pravastatin is significantly less toxi

Temporary neurological dysfunction after surgery of the thoracic aorta: a predictor of poor outcome and impaired quality of life

Background: Transient neurological dysfunction (TND) consists of postoperative confusion, delirium and agitation. It is underestimated after surgery on the thoracic aorta and its influence on long-term quality of life (QoL) has not yet been studied. This study aimed to assess the influence of TND on short- and long-term outcome following surgery of the ascending aorta and proximal arch. Methods: Nine hundred and seven patients undergoing surgery of the ascending aorta and the proximal aortic arch at our institution were included. Two hundred and ninety patients (31.9%) underwent surgery because of acute aortic dissection type A (AADA) and 617 patients because of aortic aneurysm. In 547 patients (60.3%) the distal anastomosis was performed using deep hypothermic circulatory arrest (DHCA). TND was defined as a Glasgow coma scale (GCS) value <13. All surviving patients had a clinical follow up and QoL was assessed with an SF-36 questionnaire. Results: Overall in-hospital mortality was 8.3%. TND occurred in 89 patients (9.8%). As compared to patients without TND, those who suffered from TND were older (66.4 vs 59.9 years, p<0.01) underwent more frequently emergent procedures (53% vs 32%, p<0.05) and surgery under DHCA (84.3% vs 57.7%, p<0.05). However, duration of DHCA and extent of surgery did not influence the incidence of TND. In-hospital mortality in the group of patients with TND compared to the group without TND was similar (12.0% vs 11.4%; p=ns). Patients with TND suffered more frequently from coronary artery disease (28% vs 20.8%, p=ns) and were more frequently admitted in a compromised haemodynamic condition (23.6% vs 9.9%, p<0.05). Postoperative course revealed more pulmonary complications such as prolonged mechanical ventilation. Additional to their transient neurological dysfunction, significantly more patients had strokes with permanent neurological loss of function (14.6% vs 4.8%, p<0.05) compared to the patients without TND. ICU and hospital stay were significantly prolonged in TND patients (18±13 days vs 12±7 days, p<0.05). Over a mean follow-up interval of 27±14 months, patients with TND showed a significantly impaired QoL. Conclusion: The neurological outcome following surgery of the ascending aorta and proximal aortic arch is of paramount importance. The impact of TND on short- and long-term outcome is underestimated and negatively affects the short- and long-term outcom

Persistent sensitivity disorders at the radial artery and saphenous vein graft harvest sites: a neglected side effect of coronary artery bypass grafting procedures

Objective: The use of radial artery conduits in coronary artery bypass grafting (CABG) surgery is associated with improved long-term patency and patient survival rates as compared with saphenous vein conduits. Despite increasing popularity, relative incidence of local harvest-site complications and subjective perception of adverse long-term sequelae remain poorly described. Methods: To allow for direct comparison, we investigated a consecutive series of patients in whom both the radial artery and the saphenous vein had been harvested for isolated CABG during a 36-month period. Patients were identified from a prospective database that collects baseline clinical information. The patients' own perceptions were assessed by a standardized direct telephone survey regarding any persistent functional impairment from their arm and leg operation sites. Results: Out of 1756 CABG patients during the study period, 168 (10%) were eligible (78% men, median age: 60.1 ± 9.6 years, range: 29.6-82.4 years). Of these, 123 (73%) could be contacted and interviewed at a median follow-up time of 2.5 ± 0.9 years. Surgical wound complications at harvest sites (arms and legs) had occurred in 3% and 12%, respectively, and persistent symptoms (arms and legs) were self-reported as follows: chronic pain (5% and 8%), numbness (32% and 34%) and paresthesia/dysesthesia (14% and 7%). Overall, 39% of the patients reported persistent discomfort at the arm and 39% at the leg. Both sites were simultaneously affected in 21% (P = n.s., paired testing). Logistic regression modeling showed that patients with adverse long-term sequelae were younger (P < 0.005), had a higher body mass index (P < 0.05) and a lower EuroSCORE (P < 0.001) at the time of operation (EuroSCORE, European System for Cardiac Operative Risk Evaluation). Perioperative wound complications, however, did not predict persistence of symptoms. Conclusions: Persistent harvest-site discomfort occurs with astonishing frequency after CABG surgery and affects arms and legs equally. Although usually considered a minor complication, long-term limitation to quality of life may be substantial, particularly in younger and relatively healthy patients. Thus, harvest-site discomfort clearly belongs to the list of possible post-CABG complications of which patients need to be awar

A 700-year paleoecological record of boreal ecosystem responses to climatic variation from Alaska

Copyright by the Ecological Society of America © 2008. Willy Tinner, Christian Bigler, Sharon Gedye, Irene Gregory-Eaves, Richard T. Jones, Petra Kaltenrieder, Urs Krähenbühl, and Feng Sheng Hu 2008. A 700-YEAR PALEOECOLOGICAL RECORD OF BOREAL ECOSYSTEM RESPONSES TO CLIMATIC VARIATION FROM ALASKA. Ecology 89:729–743. http://dx.doi.org/10.1890/06-1420.1Recent observations and model simulations have highlighted the sensitivity of the forest–tundra ecotone to climatic forcing. In contrast, paleoecological studies have not provided evidence of tree-line fluctuations in response to Holocene climatic changes in Alaska, suggesting that the forest–tundra boundary in certain areas may be relatively stable at multicentennial to millennial time scales. We conducted a multiproxy study of sediment cores from an Alaskan lake near the altitudinal limits of key boreal-forest species. Paleoecological data were compared with independent climatic reconstructions to assess ecosystem responses of the forest–tundra boundary to Little Ice Age (LIA) climatic fluctuations. Pollen, diatom, charcoal, macrofossil, and magnetic analyses provide the first continuous record of vegetation–fire–climate interactions at decadal to centennial time scales during the past 700 years from southern Alaska. Boreal-forest diebacks characterized by declines of Picea mariana, P. glauca, and tree Betula occurred during the LIA (AD 1500–1800), whereas shrubs (Alnus viridis, Betula glandulosa/nana) and herbaceous taxa (Epilobium, Aconitum) expanded. Marked increases in charcoal abundance and changes in magnetic properties suggest increases in fire importance and soil erosion during the same period. In addition, the conspicuous reduction or disappearance of certain aquatic (e.g., Isoetes, Nuphar, Pediastrum) and wetland (Sphagnum) plants and major shifts in diatom assemblages suggest pronounced lake-level fluctuations and rapid ecosystem reorganization in response to LIA climatic deterioration. Our results imply that temperature shifts of 1–2°C, when accompanied by major changes in moisture balance, can greatly alter high-altitudinal terrestrial, wetland, and aquatic ecosystems, including conversion between boreal-forest tree line and tundra. The climatic and ecosystem variations in our study area appear to be coherent with changes in solar irradiance, suggesting that changes in solar activity contributed to the environmental instability of the past 700 years

Technical advances improved outcome in patients undergoing surgery of the ascending aorta and/or aortic arch: ten years experience

Background: Several technical advances in thoracic aortic surgery, such as the use of antegrade cerebral perfusion, avoidance of cross-clamping and the application of glue, have beneficially influenced postoperative outcome. The aim of the present study was to analyse the impact of these developments on outcome of patients undergoing surgery of the thoracic aorta. Methods and results: Between January 1996 and December 2005, 835 patients (37.6%) out of 2215 aortic patients underwent surgery on the thoracic ascending aorta or the aortic arch at our institution. All in-hospital data were assessed. Two hundred and forty-one patients (28.8%) suffered from acute type A dissection (AADA). Overall aortic caseload increased from 41 patients in 1996 to 141 in 2005 (+339%). The increase was more pronounced for thoracic aortic aneurysms (TAA) (+367.9%), than for acute type A aortic dissections (+276.9%). Especially in TAA, combined procedures increased and the amount of patients with impaired left ventricular function (EF <50%) raised up from 14% in 1996 to 24% in 2005. Average age remained stable. Logistic regression curve revealed a significant decrease in mortality (AADA) and in the overall incidence of neurological deficits. Conclusions: Technical advances in the field of thoracic aortic surgery lead to a decrease of mortality and morbidity, especially in the incidence of adverse neurological events, in a large collective of patients. Long-term outcome and quality of life are better, since antegrade cerebral perfusion has been introduce

Return of the cadaver: Key role of anatomic dissection for plastic surgery resident training.

Successful Plastic Surgery Residency training is subjected to evolving society pressure of lower hourly work weeks imposed by external committees, labor laws, and increased public awareness of patient care quality. Although innovative measures for simulation training of surgery are appearing, there is also the realization that basic anatomy training should be re-enforced and cadaver dissection is of utmost importance for surgical techniques.In the development of new technology for implantable neurostimulatory electrodes for the management of phantom limb pain in amputee patients, a design of a cadaveric model has been developed with detailed steps for innovative transfascicular insertion of electrodes. Overall design for electrode and cable implantation transcutaneous was established and an operating protocol devised.Microsurgery of the nerves of the upper extremities for interfascicular electrode implantation is described for the first time. Design of electrode implantation in cadaver specimens was adapted with a trocar delivery of cables and electrodes transcutaneous and stabilization of the electrode by suturing along the nerve. In addition, the overall operating arena environment with specific positions of the multidisciplinary team necessary for implantable electrodes was elaborated to assure optimal operating conditions and procedures during the organization of a first-in-man implantation study.Overall importance of plastic surgery training for new and highly technical procedures is of importance and particularly there is a real need to continue actual cadaveric training due to patient variability for nerve anatomic structures