First observation of PeV-energy neutrinos with IceCube

We report on the observation of two neutrino-induced events which have an estimated deposited energy in the IceCube detector of 1.04±0.16 and 1.14±0.17 PeV, respectively, the highest neutrino energies observed so far. These events are consistent with fully contained particle showers induced by neutral-current ν(e,μ,τ) (ν(e,μ,τ)) or charged-current ν(e) (ν(e)) interactions within the IceCube detector. The events were discovered in a search for ultrahigh energy neutrinos using data corresponding to 615.9 days effective live time. The expected number of atmospheric background is 0.082±0.004(stat)(-0.057)(+0.041)(syst). The probability of observing two or more candidate events under the atmospheric background-only hypothesis is 2.9×10(-3) (2.8σ) taking into account the uncertainty on the expected number of background events. These two events could be a first indication of an astrophysical neutrino flux; the moderate significance, however, does not permit a definitive conclusion at this time.

FACS-sorted particles reduce the data variance in optical tweezers-assisted dynamic force spectroscopy measurements

By combining optical tweezers-assisted dynamic force spectroscopy experiments with fluorescence activated cell sorting (FACS), we demonstrate a new approach to reducing the data variance in measuring receptor-ligand interactions on a single molecule level by ensuring similar coating densities. Therefore, the carboxyfluorescein-labelled monophosphorylated peptide tau226-240[pThr231] is anchored on melamine resin beads and these beads are sorted by FACS to achieve a homogeneous surface coverage. To quantify the impact of the fluorescence dye on the bond parameters between the phosphorylated peptide and the corresponding phosphorylation specific anti-human tau monoclonal antibody HPT-104, we perform dynamic force spectroscopy and compare the results to data using unsorted beads covered with the non-fluorescence peptide analogue. Finally, we demonstrate that the data variance of the relative binding frequency is significantly decreased by a factor of 3.4 using pre-sorted colloids with a homogeneous ligand coating compared to using unsorted colloids.

Measurement of the atmospheric νe flux in IceCube

We report the first measurement of the atmospheric electron neutrino flux in the energy range between approximately 80 GeV and 6 TeV, using data recorded during the first year of operation of IceCube's DeepCore low-energy extension. Techniques to identify neutrinos interacting within the DeepCore volume and veto muons originating outside the detector are demonstrated. A sample of 1029 events is observed in 281 days of data, of which 496±66(stat)±88(syst) are estimated to be cascade events, including both electron neutrino and neutral current events. The rest of the sample includes residual backgrounds due to atmospheric muons and charged current interactions of atmospheric muon neutrinos. The flux of the atmospheric electron neutrinos is consistent with models of atmospheric neutrinos in this energy range. This constitutes the first observation of electron neutrinos and neutral current interactions in a very large volume neutrino telescope optimized for the TeV energy range.

Search for dark matter annihilations in the sun with the 79-string IceCube detector

We have performed a search for muon neutrinos from dark matter annihilation in the center of the Sun with the 79-string configuration of the IceCube neutrino telescope. For the first time, the DeepCore subarray is included in the analysis, lowering the energy threshold and extending the search to the austral summer. The 317 days of data collected between June 2010 and May 2011 are consistent with the expected background from atmospheric muons and neutrinos. Upper limits are set on the dark matter annihilation rate, with conversions to limits on spin-dependent and spin-independent scattering cross sections of weakly interacting massive particles (WIMPs) on protons, for WIMP masses in the range 20-5000  GeV/c2. These are the most stringent spin-dependent WIMP-proton cross section limits to date above 35  GeV/c2 for most WIMP models.

[Hindfoot arthrodesis for post-infectious ankle destruction using an intramedullary retrograde hindfoot nail]

BACKGROUND

Limb salvage after operations with deep infections of the ankle is often successful using arthrodesis of the hindfoot. The aim of this study was to evaluate the results of arthrodesis using a retrograde intramedullary nail following post-infectious ankle destruction.

PATIENTS AND METHODS

Between 2007 and 2010 a total of 44 patients were treated with tibiotalocalcaneal (TTC) arthrodesis and 14 patients with tibiocalcaneal (TC) arthrodesis using a retrograde hindfoot nail after quieting of infection. Evaluation included the American Orthopaedic Foot and Ankle Society (AOFAS) and the short-form 12-item (SF-12) scores.

RESULTS

Of the 58 patients 49 (35 male and 14 female) could be followed-up. The average time of follow-up was 18 months and the mean age was 58 years. In 85.7 % bony union could be achieved and 10.2 % suffered from reinfections. The mean results achieved in the different scores were AOFAS 56 and SF-12 39.1 (physical health summary scale) and 46.1 (mental health summary scale). Statistical analysis showed a significantly higher rate of bony fusion for TTC arthrodesis. Bony non-union showed a significant correlation to patients with reinfection and to diabetic patients.

CONCLUSIONS

Hindfoot arthrodesis for treatment of septic arthritis after infections is possible by using an intramedullary nail. The results show a high rate of fusion with an acceptable reinfection rate and good patient acceptance.

Dose sensitivity of three phantoms used for quality assurance in digital mammography

Technical quality assurance (QA) is one of the key issues in breast cancer screening protocols. For this QA task, three different methods are commonly used to assess image quality. The European protocol suggests a contrast-detail phantom (e.g. the CDMAM phantom), while in North America the American College of Radiology (ACR) accreditation phantom is proposed. Alternatively, phantoms based on image quality parameters from applied system theory such as the noise-equivalent number of quanta (NEQ) are applied (e.g. the PAS 1054 phantom). The aim of this paper was to correlate the changes in the output of the three evaluation methods (CDMAM, ACR and NEQ) with changes in dose. We varied the time-current product within a range of clinically used values (40-140 mAs, corresponding to 3.5-12.4 mGy entrance dose and detector dose of 32-110 μGy). For the ACR phantom, the examined parameter was the number of detected objects. With the CDMAM phantom we chose the diameters 0.10, 0.13, 0.20, 0.31 and 0.5 mm and recorded the threshold thicknesses. With respect to the third method, we evaluated the NEQ at typical spatial frequencies to calculate the relative changes in NEQ. Plotting NEQ versus dose increment shows a linear relationship and can be described by a linear function (with R > 0.99). Every manually selectable current- time product increment can be detected. With the ACR phantom, the number of detected objects increases only in the lower dose range and reaches saturation at about 9 mGy entrance dose (80 μGy detector dose). The CDMAM can detect a 50% increase in dose over the examined dose range with all five diameters, although the increases of threshold thickness are not monotonous. We conclude that an NEQ-based method has the potential to replace the established detail phantom methods to detect dose changes in the course of QA.

[Importance of the correct placement of the pelvic binder for stabilisation of haemodynamically compromised patients]

A 36-year-old motorcyclist sustained multiple severe injuries in a motorcycle accident. The leading injury was a type B open-book pelvic fracture, resulting in a relevant haemodynamic instability. Due to an initial misplacement of the pelvic binder (Samsling®) by the paramedics in the field, a sufficient compression of the fracture and stabilisation of the haemodynamic situation could not be obtained. After repositioning of the pelvic binder in the emergency room, the pelvis was adequately stabilised, leading to a transient stabilisation of the haemorrhagic shock. This example illustrates the benefit of a simple and effective tool for the initial stabilisation of pelvic fractures in haemodynamically compromised patients and in particular the importance of the correct placement of the pelvic binder.

Hybrid operation for a thoracoabdominal aortic aneurysm

OBJECTIVE

The treatment of thoracoabdominal aortic aneurysms remains an ongoing challenge in vascular surgery and has been associated with high periprocedural mortality. Since the introduction of endovascular procedures in the treatment of aortic pathologies during the last decade, new therapeutic options have arisen. We report here some technical aspects of a 2-step hybrid-procedure that consists of an initial debranching of all visceral arteries by perfusing them through a special vascular prosthesis, which is anastomosed to the healthy common iliac artery. The second step is performed after recovery of the patient from the debranching procedure and stentgraft prostheses are implanted to fully exclude the aneurysm.

INDICATIONS

Thoracoabdominal aortic aneurysm.

PROCEDURE

Two-step hybrid-procedure for treatment of thoracoabdominal aneurysms.

CONCLUSION

In our opinion, this procedure is, although technically demanding, safely performable with a tolerable periprocedural morbidity and mortality. Major advantages are the restriction to one visceral cavity and a sequential debranching that allows us to avoid use of a temporary bypass. This procedure appears to be a promising alternative to conventional thoracoabdominal aortic repair in centres with expertise in visceral artery revascularisation.

MRI graduation of osseous reaction and drill hole consolidation after arthroscopic Bankart repair with PLLA anchors and the clinical relevance

PURPOSE

Conventionally, radiography studies revealed prolonged glenoidal drill hole visibilities with an unclear influence to the clinical outcome after arthroscopic Bankart repair using Poly-Laevo-Lactic-Acid (PLLA) anchors. The primary aim of the present study was the separated assessment of drill hole consolidation (DHC) and the concomitant osseous reaction (OR) of the glenoidal bio-degradation process in new specific magnetic resonance grading systems. In accordance with the specific DHC and the OR graduation, the clinical relevance was the secondary focus.

METHODS

Twenty-eight patients with arthroscopic Bankart repair using knotless PLLA anchors were prospectively followed and analyzed using a clinical scoring system (3, 6, 15 and 32 months). The T2-weighted OR and T1-weighted DHC were assessed using specific magnetic resonance imaging grading protocols (15 and 32 months).

RESULTS

Longitudinal assessments revealed successive clinical status improvements over time (32 months: Rowe 95.7 ± 3.8; Walch-Duplay 93.8 ± 6.6; Constant 93.9 ± 4.5; ASES 93.8 ± 6.9; DASH 28.6 ± 7.2; NAS(pain) 1.1 ± 1.3; NAS(function) 1.3 ± 1.4). The initial OR level regressed over the 15-32 month period while the DHC showed significant drill hole reductions (P < 0.05). The inferior glenoid revealed a significantly increased bio-degradation capacity (P < 0.05) with drill hole enlargements in 14.3%. Neither the OR nor the drill hole enlargements influenced the clinical status. In no case were clinical or radiologic signs for a foreign body reaction.

CONCLUSION

Knotless bio-anchors provide secure glenoidal fixation for Bankart repair without any specific clinical or MR evidence of an inflammatory response. The clinical status remained unaffected by the bio-degradation process.

LEVEL OF EVIDENCE

IV.

[Microwave tumor ablation. New devices, new applications?]

CLINICAL ISSUE

The majority of patients with hepatic malignancies are not amenable to surgical resection. In some of these cases minimally invasive ablative therapies are a treatment option.

STANDARD TREATMENT

Besides radiofrequency ablation, the most common ablative therapies are cryoablation, laser ablation and microwave ablation.

TREATMENT INNOVATIONS

The classic fields of application of microwave ablation are the treatment of malignancies of the liver, kidneys and lungs. Furthermore, cases of treatment of bone tumors and tumors of the adrenal gland have been reported as well as treatment of secondary hypersplenism.

PERFORMANCE

The manufacturers of microwave systems pursue different strategies to reach an optimal ablation zone, such as water or gas cooling of the antenna, the simultaneous use of different antennas or an automatic modulation of the microwave energy and frequency.

ACHIEVEMENTS

In contrast to other tumor ablation methods microwave ablation causes a direct heating of a tissue volume, thus this method is less vulnerable to the cooling effect of vessels in the ablation zone. Moreover the electric conductivity of the treated tissue does not influence microwave radiation so that microwave ablation has advantages for the treatment of high-resistance organs, such as the lungs or bone. Some publications have shown that microwave ablation causes larger ablation zones in less time in comparison to radiofrequency ablation.

PRACTICAL RECOMMENDATIONS

Classic indications for microwave ablation are the treatment of malignancies of the liver, lungs and kidneys. Initial technical problems have been solved, so that an increasing significance of the microwave ablation among the ablative therapies is to be expected.

Novel peptide-protein assay for identification of antimicrobial peptides by fluorescence quenching

The specific interaction of peptides with proteins is often a key factor which determines biological activities. The determination of K(d) values of such interactions is commonly performed with fluorescence polarization. However, fluorescence polarization assays are prone to false-positive results due to the potential for non-specific interactions and only afford very low signal-to-background ratios. Here, we present as an alternative a fluorescence resonance energy transfer based quenching assay to measure peptide-protein interactions in solution. In a test setup where antimicrobial peptides were tested for their affinity towards the protein DnaK, the assay provided high specificity and good reproducibility and correlated with the results obtained by fluorescence polarization methods. Furthermore, we established a fast prescreening method which will allow a highly efficient screening of peptide libraries by reducing the amount of sample by 98% compared to conventional fluorescence polarization assays.

[Web-based evidence of treatment capacity. An instrument for optimizing the interface between prehospital and hospital management]

BACKGROUND

The outcome of injured patients depends on intrastractural circumstances as well as on the time until clinical treatment begins. A rapid patient allocation can only be achieved occur if informations about the care capacity status of the medical centers are available. Considering this an improvement at the interface prehospital/clinical care seems possible.

MATERIAL AND METHOD

In 2010 in Frankfurt am Main the announcement of free capacity (positive proof) was converted to a web-based negative proof of interdisciplinary care capacities. So-called closings are indicated in a web portal, recorded centrally and registered at the local health authority and the management of participating hospitals.

RESULTS

Analyses of the allocations to hospitals of all professional disciplines from the years 2009 and 2010 showed an optimized use of the resources. A decline of the allocations by the order from 261 to 0 could be reached by the introduction of the clear care capacity proof system. The health authorities as the regulating body rarely had to intervene (decline from 400 to 7 cases). Surgical care in Frankfurt was guaranteed at any time by one of the large medical centers.

CONCLUSION

The web-based care capacity proof system introduced in 2010 does justice to the demand for optimum resource use on-line. Integration of this allocation system into the developing trauma networks can optimize the process for a quick and high quality care of severely injured patients. It opens new approaches to improve allocation of high numbers of casualties in disaster medicine.

[Ankle fractures in the elderly]

There has been a significant increase in the incidence and severity of ankle fractures in the elderly population in the last few decades. Classification and diagnostic procedures in the elderly are not different from standards in younger patients. We provide an overview of the characteristic features of treatment of ankle fractures in the elderly. An algorithm for therapy of ankle fractures in the elderly is presented.

[Operative treatment of proximal humeral four-part fractures in elderly patients: comparison of two angular-stable implant systems]

AIM

Although being one of the most common fractures in elderly patients, there is still no standardised treatment protocol for four-part fractures of the proximal humerus. However, a wide variety of angular-stable implants is available. The present retrospective study compares the clinical and radiological outcome following operative treatment of four-part fractures of the proximal humerus with the Philos system (Philos, proximal humeral internal locking system, Synthes GmbH, Umkirch Germany) and the angular-stable Königsee plate system (Königsee Implantate GmbH, Allendorf, Germany) in patients older than 65 years.

METHODS

From July 2005 until December 2007 we identified 77 patients with a four-part fracture of the proximal humerus who were treated operatively with one of the two implant systems. Of the patients, 17 could not be located so that in total 60 patients (78 %) participated in this study. The mean age of the 30 patients (10 m, 20 f) in the Philos group was 69 years (65-92), whereas the mean age of the 30 patients (11 m, 19 f) in the Königsee group was 71 years (65-93). A comprehensive assessment was performed after a median of 17 months (12-24), including physical examination, radiographic examination and completion of the disabilities of the arm, shoulder and hand score (DASH) and the Constant score (CS) as patient-oriented, limb-specific questionnaires.

RESULTS

Neither in the Philos nor in the Königsee group could excellent results be achieved. Using the CS 13 patients (43 %) of the Philos group achieved a good and 15 (50 %) a satisfactory result. Bad results were found in 2 patients (7 %). The mean CS was 61.53 points. In the Königsee group mean CS was 61.76 points. In detail, 14 patients (47 %) treated with the Königsee implant were rated as good and 15 (50 %) as satisfactory. Only 1 patient (3 %) was rated as poor. No significant statistical differences were found between the groups. Mean DASH score in the Philos group was 56.30 points and 55.37 points in the Königsee group. Again, no statistical difference was found. Partial humeral head necrosis was observed in 2 patients of the Philos and 1 of the Königsee group. In the remaining patients uneventful fracture consolidation was observed. There were no complications requiring further surgical intervention. To the date of follow-up all implants were still in situ and none of the patients reported discomfort with respect to the hardware.

CONCLUSION

In this study we were able to demonstrate that good and satisfactory results can be achieved in the majority of patients, regardless of whether a Philos or a Königsee system was used. Significant differences between the two groups could not be found in any of the performed examinations. Both implants seem to be suitable in four-part fractures of the proximal humerus. However, the Königsee plate represents a more cost-effective option compared to the Philos system.

Stenotrophomonas maltophilia in the respiratory tract of medical intensive care unit patients

The purpose of this study was to investigate characteristics of critically ill patients with Stenotrophomonas maltophilia (S. maltophilia) isolated from the respiratory tract, to identify risk factors for S. maltophilia-pneumonia and intensive care unit (ICU) mortality and to analyze antibiotic susceptibility of S. maltophilia. This was a retrospective analysis of 64 medical ICU patients with S. maltophilia in the respiratory tract. Thirty-six patients fulfilled the criteria for diagnosis of pneumonia. A significantly higher lung injury score (LIS) was observed in patients with pneumonia compared to patients with colonization (p=0.010). Independent risk factors for S. maltophilia-pneumonia were higher Sequential Organ Failure Assessment (SOFA) score (p=0.009) and immunosuppression (p=0.014). Patients with S. maltophilia-pneumonia had higher ICU mortality within a 28-day follow-up (p=0.040) and higher hospital mortality (p=0.018) than patients with colonization. The highest antibiotic susceptibility rates were observed to trimethoprim-sulfamethoxazole, tigecycline, and moxifloxacin. Higher SOFA score when S. maltophilia was isolated (p=0.001) and development of renal failure (p=0.021) were independent risk factors for ICU mortality. Higher SOFA score and immunosuppression are independent risk factors for S. maltophilia-pneumonia. Patients with S. maltophilia-pneumonia have a significantly higher ICU mortality within a 28-day follow-up, hospital mortality and LIS compared to patients with S. maltophilia-colonization.

[Osteomyelitis of the costae caused by salmonella]

Salmonella enterica serotype Enteritidis was detected in a 34-year-old, previously healthy patient who suffered from osteomyelitis of the costae. Radical surgical debridement and antibiotic therapy were able to stop the infection. An abdominal flap and a thoracic flap were used to cover the soft tissue defect.

[Injuries to the upper cervical spine. Part 2: osseous injuries]

This article for continuing education describes osseous injuries of the upper cervical spine and their treatment. Fractures of the occipital condyles are very rare and mostly result from high-speed traumas. These are usually managed conservatively. Atlas fractures can also usually be treated with immobilization of the cervical spine; in cases of unstable or dislocated injuries, various surgical procedures are employed. Three types of axis fractures can be distinguished: odontoid fractures, traumatic spondylolistheses, which also affect the isthmic region, and atypical fractures in the corpus region. The incidence, classification, diagnostic workup, standard treatment, and characteristics of the fractures mentioned are presented in detail.

Cubital tunnel syndrome - a review and management guidelines

Cubital tunnel syndrome (CuTS) is the second most common peripheral nerve compression syndrome. In German-speaking countries, cubital tunnel syndrome is often referred to as sulcus ulnaris syndrome (retrocondylar groove syndrome). This term is anatomically incorrect, since the site of compression comprises not only the retrocondylar groove but the cubital tunnel, which consists of 3 parts: the retrocondylar groove, partially covered by the cubital tunnel retinaculum (lig. arcuatum or Osborne ligament), the humeroulnar arcade, and the deep flexor/pronator aponeurosis. According to Sunderland , cubital tunnel syndrome can be differentiated into a primary form (including anterior subluxation of the ulnar nerve and compression secondary to the presence of an anconeus epitrochlearis muscle) and a secondary form caused by deformation or other processes of the elbow joint. The clinical diagnosis is usually confirmed by nerve conduction studies. Recently, the use of ultrasound and MRI have become useful diagnostic tools by showing morphological changes in the nerve within the cubital tunnel. A differential diagnosis is essential in atypical cases, and should include such conditions as C8 radiculopathy, Pancoast tumor, and pressure palsy. Conservative treatment (avoiding exposure to external noxes and applying of night splints) may be considered in the early stages of cubital tunnel syndrome. When nonoperative treatment fails, or in patients who present with more advanced clinical findings, such as motor weakness, muscle atrophy, or fixed sensory changes, surgical treatment should be recommended. According to actual randomized controlled studies, the treatment of choice in primary cubital tunnel syndrome is simple in situ decompression, which has to be extended at least 5-6 cm distal to the medial epicondyle and can be performed by an open or endoscopic technique, both under local anesthesia. Simple decompression is also the therapy of choice in uncomplicated ulnar luxation and in most post-traumatic cases and other secondary forms. When the luxation is painful, or when the ulnar nerve actually "snaps" back and forth over the medial epicondyle of the humerus, subcutaneous anterior transposition may be performed. In cases of severe bone or tissue changes of the elbow (especially with cubitus valgus), the anterior transposition of the ulnar nerve may again be indicated. In cases of scarring, submuscular transposition may be preferred as it provides a healthy vascular bed for the nerve as well as soft tissue protection. Risks resulting from transposition include compromise in blood flow to the nerve as well as kinking of the nerve caused by insufficient proximal or distal mobilization. In these cases, revision surgery is necessary. Epicondylectomy is not common, at least in Germany. Recurrence of compression on the ulnar nerve at the elbow may occur. This review is based on the German Guideline "Diagnose und Therapie des Kubitaltunnelsyndroms" ( www.leitlinien.net ).