Constraints on Cosmology and Gravity from the Dynamics of Voids.

The Universe is mostly composed of large and relatively empty domains known as cosmic voids, whereas its matter content is predominantly distributed along their boundaries. The remaining material inside them, either dark or luminous matter, is attracted to these boundaries and causes voids to expand faster and to grow emptier over time. Using the distribution of galaxies centered on voids identified in the Sloan Digital Sky Survey and adopting minimal assumptions on the statistical motion of these galaxies, we constrain the average matter content Ω_{m}=0.281±0.031 in the Universe today, as well as the linear growth rate of structure f/b=0.417±0.089 at median redshift z[over ¯]=0.57, where b is the galaxy bias (68% C.L.). These values originate from a percent-level measurement of the anisotropic distortion in the void-galaxy cross-correlation function, ϵ=1.003±0.012, and are robust to consistency tests with bootstraps of the data and simulated mock catalogs within an additional systematic uncertainty of half that size. They surpass (and are complementary to) existing constraints by unlocking cosmological information on smaller scales through an accurate model of nonlinear clustering and dynamics in void environments. As such, our analysis furnishes a powerful probe of deviations from Einstein's general relativity in the low-density regime which has largely remained untested so far. We find no evidence for such deviations in the data at hand.

Universal density profile for cosmic voids.

We present a simple empirical function for the average density profile of cosmic voids, identified via the watershed technique in ΛCDM N-body simulations. This function is universal across void size and redshift, accurately describing a large radial range of scales around void centers with only two free parameters. In analogy to halo density profiles, these parameters describe the scale radius and the central density of voids. While we initially start with a more general four-parameter model, we find two of its parameters to be redundant, as they follow linear trends with the scale radius in two distinct regimes of the void sample, separated by its compensation scale. Assuming linear theory, we derive an analytic formula for the velocity profile of voids and find an excellent agreement with the numerical data as well. In our companion paper [Sutter et al., arXiv:1309.5087 [Mon. Not. R. Astron. Soc. (to be published)]], the presented density profile is shown to be universal even across tracer type, properly describing voids defined in halo and galaxy distributions of varying sparsity, allowing us to relate various void populations by simple rescalings. This provides a powerful framework to match theory and simulations with observational data, opening up promising perspectives to constrain competing models of cosmology and gravity.

Cosmology with void-galaxy correlations.

Galaxy bias, the unknown relationship between the clustering of galaxies and the underlying dark matter density field is a major hurdle for cosmological inference from large-scale structure. While traditional analyses focus on the absolute clustering amplitude of high-density regions mapped out by galaxy surveys, we propose a relative measurement that compares those to the underdense regions, cosmic voids. On the basis of realistic mock catalogs we demonstrate that cross correlating galaxies and voids opens up the possibility to calibrate galaxy bias and to define a static ruler thanks to the observable geometric nature of voids. We illustrate how the clustering of voids is related to mass compensation and show that volume-exclusion significantly reduces the degree of stochasticity in their spatial distribution. Extracting the spherically averaged distribution of galaxies inside voids from their cross correlations reveals a remarkable concordance with the mass-density profile of voids.

Principles of operative treatment of malleolar fractures today.

Ankle fractures continue to be a common injury. They involve various mechanisms of injury and produce, when treated correctly, fairly good results. Although non-displaced stable malleolar fractures are treated safely by conservative means, displaced unstable fractures are still the domain of open reduction and internal fixation (ORIF), as recommended by the AO Group. The principles of the operative treatment of these fractures are discussed in this paper, illuminating the surgical technique and biomechanics of lateral, medial and posterior malleolar fractures. Even though there have been no fundamental changes in the treatment of these fractures in the last several years, new implants such as angular-stable plates and new surgical techniques such as the minimally invasive plate osteosynthesis (MIPO) technique help to treat these fractures more individually, depending on the type of fracture, quality of bone and soft tissue conditions.

[5 years ATLS (Advanced Trauma Life Support) courses in Switzerland]. / Fünf Jahre ATLS-Kurse in der Schweiz.

Five years ATLS (Advanced Trauma Life Support) in Switzerland are analysed, the problems are discussed and the changes during this period are demonstrated. ATLS Switzerland is a part of the Swiss surgical Society, introduced by the ATLS International Faculty in 1998. Switzerland with 4 official languages needs a special structure. For this reason a decentralisation of the courses was necessary with the need of five regional universities where ATLS courses are offered. Statistics of the rising amount of courses demonstrate the enormous rush for ATLS courses in our country. Three courses in 1998 where followed by six courses in 1999, up to 18 courses in 2002. 2001 was the first year with ATLS in the Swiss Army. Since 1.1.2003 Paul Martin Sutter, Biel ist the new National Director, successor of Domenic Scharplatz, Thusis.

[(Impending) pathological fracture]. / (Drohende) pathologische Fraktur.

Pathological fractures will be encountered in increasing frequency due to more patients with cancer, surviving a longer period. The skeleton is the third most frequent localization for metastases. Breast cancer is still the most common primary tumor, but bone metastases from lung cancer seem to be diagnosed more and more. Despite of finding metastases most often in the spinal column, fractures are seen mostly at the femoral site. A pathological fracture and, in almost all cases, an impending fracture are absolute indication for operation. An exact definition of an "impending fracture" is still lacking; it is widely accepted, that 50 per cent of bone mass must be destroyed before visualization in X-ray is possible, thus defining an impending fracture. The score system by Mirels estimates the fracture risk by means of four parameters (localization, per cent of destructed bone mass, type of metastasis, pain). Improving quality of life, relieving pain, preferably with a single operation and a short length of stay are the goals of (operative) treatment. For fractures of the proximal femur, prosthetic replacement, for fractures of the subtrochanteric region or the shaft, intramedullary nails are recommended. Postoperative radiation therapy possibly avoids tumor progression. In patient with a good long term prognosis, tumor should be removed locally aggressive.

Team performance in the emergency room: assessment of inter-disciplinary attitudes.

In-hospital emergency medicine in central Europe relies on inter-disciplinary co-operation. To improve team performance in the emergency room (ER), a questionnaire for assessment of attitudes and judgements in resuscitation procedures was developed. A total of 43 items were evaluated according to a five-point Likert scale. With a response rate of 81%, 143 questionnaires were evaluated. Assessment of data was performed with regard to professional speciality and level in the medical hierarchy. Factorial analysis identified four main factors: Assessment of 'quality of performance' (F1), 'importance of structure' (F2), 'quality of team culture' (F3), and 'importance of hierarchy' (F4). Influences from the categories 'speciality' and 'hierarchy' and from the covariate 'gender' on these main factors were evaluated by two-factorial analysis of variance. For all four factors, 'speciality' produced significant differences. Surgeons accorded high values to F1 and low values to F2, whereas anaesthesiologists accorded low values to F1 and high values to F2. F3 showed a low ranking from within the ER nursing staff and the residents in internal medicine, whereas F4 received high scores by medical residents and staff members. For F1 and F3, there was a tendency towards hierarchy dependency, whereas no factor was influenced by gender. In conclusion, team performance in the ER is mainly influenced by different perceptions and attitudes of the different disciplines involved in the resuscitation process.

Preconditioning with short cycles improves ischemic tolerance in rat fast- and slow-twitch skeletal muscle.

AIM: The aim of this study was to investigate whether the efficacy of ischemic preconditioning (IP) in rat skeletal muscle depends on the duration of the preconditioning cycles. METHODS: Rats were divided into four groups (n = 10 each). The right hindlimb of rats in group A were subjected to 2.5 h of tourniquet ischemia followed by 2 h of reperfusion (I-R). Thereafter, muscular function was analyzed in vitro and high-energy phosphates (HEP) were determined by HPLC. Before I-R, right hindlimbs of rats in groups B-D subjected to IP with three cycles each consisting of 2.5, 5 or 10 min of ischemia followed by reperfusion for the same duration. RESULTS: Postischemic function of the extensor muscle was significantly improved with all three preconditioning protocols. Postischemic function of the soleus muscle was only improved by IP with three cycles of 5 min of ischemia and 5 min of reperfusion. Postischemic HEP tissue levels were not influenced by IP. CONCLUSION: This study shows for the first time that IP increases ischemic tolerance not only of fast-twitch but also of slow-twitch skeletal muscle. The efficacy of IP seems to be less dependent on the duration of the single preconditioning cycle than on the number of cycles performed. Three cycles each of 2.5, 5 or 10 min ischemia and reperfusion significantly improved postischemic skeletal muscle function. Tissue levels of HEPs, however, were not influenced by IP indicating that preservation of HEPs does not play a major role in the effects of IP on rodent skeletal muscle.

Mechanisms of ischemic preconditioning in skeletal muscle.

BACKGROUND: Ischemic preconditioning (IP) (one or more cycles each consisting of a short period of ischemia and a short period of reperfusion, before the sustained ischemia) reduces ischemia-related organ damage in heart and skeletal muscle but the underlying mechanisms are not clear. This study was intended to assess the possible involvement of K(ATP) channels and of adenosine receptors in IP of skeletal muscle in a rat model of skeletal muscle ischemia. MATERIALS AND METHODS: Groups of 8-15 rats were given the following in vivo treatments: ischemia-reperfusion (I-R: 2.5 h tourniquet-induced ischemia of the right hindlimb, then 2 h reperfusion); IP (three cycles of 5 min ischemia, then 5 min reperfusion) before I-R; cromakalim and I-R; glibenclamide, cromakalim, and I-R; glibenclamide, IP, and I-R; [R]-N(6)-[1-methyl-2-phenylethyl]adenosine (R-PIA) and I-R; adenosine and I-R; and glibenclamide, IP, and I-R. Parameters of muscle function (postischemic maximal force, performance, contraction index, and force after 1 min of stimulation) were then assessed in vitro in the extensor digitorum longus muscle. RESULTS: Pretreatment with either IP or the K(ATP) channel opener cromakalim significantly improved postischemic muscle function. The protective effect of cromakalim was not seen when the K(ATP) channel blocker glibenclamide was added. Glibenclamide, however, did not block IP-induced protection. Pretreatment with the adenosine A(1) receptor agonist 8-(p-sulfophenyl)-theophyllin (8-SPT) or with adenosine did not improve postischemic muscle function. The adenosine receptor agonist did not block IP-induced protection against ischemic damage. CONCLUSIONS: The results show significant improvements in postischemic skeletal muscle function after IP or cromakalim pretreatment but they do not support a role for K(ATP) channels or for adenosine receptors in IP of skeletal muscle.

Function of fast- and slow-twitch rat skeletal muscle following ischemia and reperfusion at different intramuscular temperatures.

Fast- (peroneal) and slow-twitch (soleus) skeletal muscles of anesthetized Wistar rats were subjected to 3 h of tourniquet ischemia. The intramuscular temperature of the leg was adjusted to 22, 30 or 35 degrees C (n = 12 per group) during ischemia. After 2 h of reperfusion, the muscles were electrically stimulated in vitro and muscular function was analyzed for maximal force, performance, contractility and fatigue. Contralateral nonischemic muscles served as controls. Three hours of ischemia at 30 degrees C did not reduce the function of the peroneal muscles compared to nonischemic controls. The same ischemic stress significantly reduced the function of the soleus muscles compared to nonischemic controls. The postischemic function of the soleus muscles declined with increasing temperature. The postischemic function of the 35 degrees C group of peroneal muscles was significantly reduced compared to the 22 and the 30 degrees C groups, which did not differ. These results provide evidence that fast-twitch muscles are more resistant to ischemia than slow-twitch muscles. They furthermore show a fiber type-specific dependency of postischemic muscle function on intramuscular temperature during ischemia. Hypothermia-sensitive fast-twitch fibers predominate in the skeletal muscles of the extremities. Mild hypothermia could, therefore, reduce tourniquet ischemia-induced injury after surgery of the extremities.

[ATLS (advanced trauma life support) in Switzerland]. / ATLS (Advanced Trauma Life Support) in der Schweiz.

We analysed the ATLS courses organized in Switzerland since 1998. At the students courses the surgeons exceed the participants with a percentage of 45.7%, followed by the anaesthesiologist with 36.3%. The senior residents dominate with 49.1%, followed by the residents with 42.3%. The chief surgeons come only to a per cent of 4.1%. The statistics of the instructors show about the same pattern, the percentage of senior residents is even more impressive. The aim of ATLS is the same concept, the idea of ATLS in all emergency units throughout the whole country of Switzerland.

Muscle biopsy for malignant hyperthermia screening in children.

Malignant Hyperthermia (MH) remains a life-threatening event in anaesthetic practice. In paediatric patients, triggering agents such as volatile anaesthetics and other succinylcholine are widely used. For children with a positive family history or previous clinical signs of MH, muscle biopsy for the halothane and caffeine in vitro muscle contracture tests is the only reliable procedure for diagnosis of MH susceptibility. Here we investigated outcome and compliance of patients and parents involved in the test. Twenty-four children between 6 and 14 yrs of age were admitted to hospital for biopsy. Muscle withdrawal was performed at the upper leg from lateral vastus muscle using regional or trigger-free general anaesthesia. Outcome and compliance were controlled by a telephone interview or direct physical re-evaluation. Seventeen patients out of 24 were diagnosed as clinically MH-susceptible according to the protocol of the European MH Group. Seven children were excluded as MH-negative by the test. Twenty-one children were evaluated postoperatively. Minor side effects of wound healing occurred, but none of the patients showed any abnormalities of muscle contracture or movement performance. Considering the high risk of fatal complications in the presence of MH-susceptibility, muscle biopsy of the upper leg for in-vitro diagnosis is a justified procedure that is acceptable to children and their parents.

Increased surface expression of CD18 and CD11b in leukocytes after tourniquet ischemia during elective hand surgery.

The surface expression of beta2-integrins was investigated in leukocytes from patients undergoing ischemia induced by tourniquet application for elective hand surgery. Blood samples were obtained before initiation, at the end of ischemia, and after 15 minutes of reperfusion from ischemic and contralateral arms of five patients. Comparable expression of CD18, CD11a, CD11b, and CD11c could be detected by immunofluorescence in leukocytes from samples drawn from either arm before tourniquet application. In contrast, a significant increase in the expression of CD18 was detectable in monocytes, granulocytes, and lymphocytes from the ischemic arm compared with that in the nonischemic contralateral control, at the end of the ischemia time (80 +/- 16 minutes). A significantly increased expression of CD11b, but not CD11a or CD11c, determinants was also observed in granulocytes and monocytes. Concomitantly, a significant reduction in the percentages of granulocytes in samples from ischemic areas was detectable. After 15 minutes of reperfusion, differences in the expression of these adhesion molecules were no longer significant. The expression of the genes encoding interleukins IL-1alpha, IL-1beta, and IL-6 and tumor necrosis factor alpha (TNFalpha) proinflammatory cytokines was also studied by reverse polymerase chain reaction (rPCR) in peripheral blood mononuclear cells (PBMCs) obtained from the same samples in three patients. IL-1beta or IL-6 gene expression was never observed. Expression of IL-1alpha and TNFalpha genes, as detected in two patients, was not related with induction of ischemia. However, in these patients expression of one or both these genes was observed in samples derived from the ischemic but not the control arm after 15 minutes of reperfusion. These data document that overexpression of adhesion molecules and sequestration of leukocytes take place following short ischemia times, as routinely applied clinically for minor surgical procedures.

[Carcinoid tumor in Meckel's diverticulum: case presentation and review of the literature]. / Karzinoidtumor in einem Meckel-Divertikel: Fallvorstellung und Review der Literatur.

Meckel's diverticulum is the most common anomaly of the gastrointestinal tract. Neoplasms are extremely rare. We report a case of carcinoid tumor of Meckel's diverticulum in a patient with acute abdominal pain. So far, 111 cases have been reported. Review of the literature reveals that carcinoids are the most common malignant tumors of Meckel's diverticulum. Two thirds of the patients remain asymptomatic. Metastases are seen in 25% at diagnosis. The probability of metastases depends on the size of the primary tumor. Because of the early metastases rate even in small tumors, aggressive surgical management is justified.

Ischemic preconditioning improves post-ischemic skeletal muscle function.

Ischemic preconditioning (IP), using one or more brief periods of ischemia before a sustained ischemia, represents a new approach to reduce tourniquet ischemia-induced skeletal muscle damage. The aim of this study was to investigate the effect of IP on skeletal muscle function and high-energy phosphate tissues levels in a rodent model. IP protocols using one, two, or three preconditioning cycles were compared. IP was found to significantly improve force, performance, endurance, and contractility of postischemic skeletal muscle. The efficacy of IP-induced protection was correlated with the number of preconditioning cycles. Preconditioning with three cycles resulted in a more effective protection as compared to one or two cycles. Three cycles of IP significantly improved force (409 +/- 63 versus 240 +/- 47 mN), performance (2546 +/- 481 versus 1081 +/- 242 mN*sec), endurance (46.7 +/- 5.0 versus 29.6 +/- 3.4 sec) and contractility (59.9 +/- 4.2 versus 38.7 +/- 5.1) in postischemic m.extensor dig. long. when compared to nonpreconditioned muscles. In contrast, high-energy phosphate tissue levels remained unchanged after three cycles of preconditioning. Altogether, this study describes, for the first time, the efficacy of IP to improve postischemic muscle function. The respective clinical potential warrants further exploration.

[Ischemic preconditioning improves post-ischemic function but not energy metabolism of skeletal muscles]. / Il precondizionamento ischemico migliora la funzione postischemica ma non il metabolismo energetico della muscolatura scheletrica.

Ischemic preconditioning (IP) refers to a phenomenon whereby short periods of ischemia reduce tissue damage after a subsequent sustained ischemia. The effect of IP before tourniquet ischemia of the extremities has not yet been evaluated. We developed a rat model of skeletal muscle ischemia and measured the effect of IP on postischemic function and high-energy phosphate levels. IP consisted in three cycles of 10 min ischemia and 10 min reperfusion each. IP improved significantly skeletal muscle function after 3 hours of ischemia and 2 hours of reperfusion. High-energy phosphate levels, however, remained unchanged. This study shows a protective effect of IP in skeletal muscles. These results furthermore suggest that the protection of energy metabolism is not a mechanism of IP in this model. IP could be easily performed before surgery of the extremities under tourniquet ischemia. The protective effect on postischemic skeletal muscle has therefore to be further investigated.

Ischemic preconditioning--a new concept in orthopedic and reconstructive surgery.

The duration of tourniquet-induced ischemia during orthopedic and reconstructive surgery is limited by the risk of ischemia and reperfusion injury to skeletal muscle. This study evaluated the potential of ischemic preconditioning (short periods of ischemia with intermittent reperfusion) to improve skeletal muscle function after ischemia and reperfusion in a rodent model. Preconditioning was found to improve force, contractility, and performance and to decrease fatigue of skeletal muscle. In contrast, energy-rich phosphates, measured concurrently, were not affected by preconditioning, suggesting mechanisms other than energy preservation to be involved. In summary, preconditioning may enable prolongation of orthopedic and reconstructive procedures.

Effects of verapamil on skeletal muscle function following ischemia and reperfusion.

Verapamil (VRP) improves ischemic tolerance of different organs including brain, kidney, liver and heart. We report here on the effects of preischemic VRP treatment on skeletal muscle function following 3 h of tourniquet ischemia and 2 h of reperfusion using a rodent model. Postischemic and contralateral limbs were evaluated. Fast (musculi peronei)- and slow-twitch muscles (musculus soleus) of both limbs were excised and electrically stimulated in vitro. VRP pretreatment was found to significantly decrease tetanic peak tension of both contralateral nonischemic m. soleus and mm. peronei. Furthermore, VRP improved fatigability of slow-twitch muscles of both ischemic and contralateral limbs [increase of fatigue index from 0.04 +/- 0.009 (0 mg/kg) to 0.10 +/- 0.019 (4 mg/kg)], but not of fast-twitch muscles. These data indicate that the effects of VRP on postischemic skeletal muscle function depend on fiber composition.

[Effects of allopurinol on damage caused by ischemia and reperfusion of skeletal muscles: an in vivo spectroscopic analysis (31P-MR) in rats]. / Effetto dell'allopurinolo sui danni causati da ischemia e riperfusione nella muscolatura scheletrica: un'analisi spettroscopica (31P-RM) in vivo nel ratto.

The effect of allopurinol on energetic metabolism (reutilization of hypoxanthine) has been studied in vivo by mean of 31P-RM spectroscopy on skeletal muscle in the rat in conditions of ischemia and reperfusion. The treatment with allopurinol demonstrates of on benefit or phosphocreatine and ATP kinetics. These results outline that reutilization of hypoxanthine doesn't represent a protective mechanism of allopurinol on skeletal muscles. The role of hypoxanthine reutilization has to be investigated with further researches.