In Vivo Assessment of Shear Wave Propagation in Pennate Muscles Using an Automatic Ultrasound Probe Alignment System

Goal: Skeletal muscle mechanics can be assessed in vivo using shear wave elastography. However, the impact of pennation angle on shear wave velocity (SWV) remains unclear. This study aims to quantify the effect by automatically aligning the ultrasound probe with muscle fiber orientation. Methods: We propose an automatic ultrasound probe alignment system and compare it to manual and no alignment. SWV of the gastrocnemius medialis muscle of ten volunteers was measured during rest and isometric contractions. Results: The SWV was different between the conditions (p = 0.008). The highest SWV was obtained during the automatic alignment and differences between the conditions were most pronounced during high-level contractions. The automatic system yielded more accurate alignment compared to a manual operator (p = 0.05). Conclusions: The present study indicates that pennation angle affects SWV, hence muscle fiber orientation must be considered to reliably interpret SWV. Using automatic alignment systems allows for more accurate alignment, improving the methodology of ultrasound elastography in skeletal muscles.

Pulmonary vein isolation with high power, short duration ablation leads to shorter procedure times associated with high success rates: a Prospective Randomized Trial

Funding Acknowledgements

Type of funding sources: None.

Background

The single procedure success rates of durable pulmonary vein isolation (PVI) for paroxysmal atrial fibrillation (AF) varies between 85 and 90 %.

This prospective, randomized study investigated the efficacy of high power, short duration ablation in a temperature-controlled mode versus standard power settings in terms of single-procedure arrhythmia-free outcome, safety and procedural time.

Methods and results

A total number of 176 patients undergoing de-novo catheter ablation for paroxysmal AF were randomized to two different treatment arms. In group-A patients, PVI was performed with RF-energy with standard power settings of 30 Watts in a temperature-controlled mode.

The ablation procedure in group B was performed with RF-energy with higher power settings of 45 Watts. In both groups the ablation was performed with ablation index (AI) and following the CLOSE protocol (Biosense Webster Thermocool STSF).

A total of 88 patients were randomized into each group without significant differences in baseline characteristics.

During a mean follow-up of 12 ± 4 months after a single procedure, 79 (90%) patients of group A were free of arrhythmia recurrence versus 82 (93 %) patients in group B (p=ns).

With regard to the procedural data, the procedure time was significantly shorter in group B (115.35 ± 15.38 versus 96.45 ± 17.19; p<0.01), the flouroscopy time and dose area were also significantly lower in Group B (9.66 ± 3.86 vs 5.45 ± 2.35; 330.84 ± 150.36 vs 202.51 ± 135.23) and total ablation times were significantly shorter in group B ((Table 1). Both procedures were performed with a low number of complications, no pericardial effusion was seen in either group, in both groups two patients had a significant hematoma of the groin with the need of surgical repair.

Conclusions

RF-ablation with high power (45 Watts) in combination with ablation index and following the CLOSE protocol leads to shorter procedure times, a lower total ablation time and a good safety profile.

Tunable electrochromic filter for in situ Fourier spatial frequency filtering

Spatial optical Fourier filtering is a widespread technique for in situ image or light field processing. However, conventional fixed absorbing patterns or mechanical irises only allow an inflexible, very restricted control. Thus, we present two electrochromic spatial filters with ring-shaped or directional segments, which can be individually addressed and continuously tuned in transmission resulting in up to 512 different filtering states. For realization of the electrochromic devices, we overcome technical obstacles to realize seamless, gap-free electrochromic segments. We describe this novel fabrication process and demonstrate the successful application in an optical Fourier transform set-up.

Experimental Studies on the Antithrombotic Action of a Highly Effective Synthetic Thrombin Inhibitor

The antithrombotic action of the highly effective synthetic thrombin inhibitor Nα-(2-naphthylsulfonylglycyl)-4-amidino-phenylalanine piperidide was studied in various models of experimental thrombosis in rats. Intravenous infusion of the thrombin inhibitor caused a dose-dependent inhibition or prevention of stasis-induced venous thrombosis, of arterial thrombosis after electrically-induced damage of the vessel wall and of thrombotic occlusion of an extracorporeal arterio-venous shunt.

Anticoagulant and Antithrombotic Action of Novel Specific Inhibitors of Thrombin

A series of new specific inhibitors of thrombin, cyclic amides of Nα-arylsulfonyl-amidinophenylalanine, was studied for anticoagulant action in vitro and in vivo. The inhibitors showed strong anticoagulant effects in vitro. The time course of the anticoagulant effect of the inhibitors in rabbits and rats was monitored using plasma thrombin time determinations. In rats, the inhibitors prevented the formation of experimental venous thrombi and of thrombin-induced microthrombosis. The new derivatives of benz-amidine presented may be useful as immediately acting anticoagulants.

Comparison of the Anticoagulant and Antithrombotic Effects of Synthetic Thrombin and Factor Xa Inhibitors

The anticoagulant effect of selected synthetic inhibitors of thrombin and factor Xa was studied in vitro in commonly used clotting assays. The concentrations of the compounds doubling the clotting time in the various assays were mainly dependent on their thrombin inhibitory activity. Factor Xa inhibitors were somewhat more effective in prolonging the prothrombin time compared to the activated partial thromboplastin time, whereas the opposite was true of thrombin inhibitors.

In vivo, in a venous stasis thrombosis model and a thromboplastin-induced microthrombosis model in rats the thrombin inhibitors were effective antithrombotically whereas factor Xa inhibitors of numerically similar IQ value for the respective enzyme were not effective at equimolar dosage

The results are discussed in the light of the different prelequisiles and conditions for inhibition of thrombin and factor Xa in the course of blood clotting.

Silicon based tandem cells: novel photocathodes for hydrogen production

A photovoltaic tandem cell made of amorphous silicon (a-Si) and microcrystalline silicon (μc-Si) was investigated as a photocathode for hydrogen evolution in a photoelectrochemical device. The electronic and electrochemical properties of the samples were characterized using X-ray photoemission spectroscopy (XPS) and cyclic voltammetry (CV), whereas the morphology of the surface in contact with the electrolyte was investigated by scanning electron microscopy (SEM). The electric efficiency of the tandem cell was determined to be 5.2% in a photoelectrochemical (PEC) setup in acidic solution which is only about half of the photovoltaic efficiency of the tandem cell. A significant improvement in efficiency was achieved with platinum as a catalyst which was deposited by physical vapour deposition (PVD) under ultra-high vacuum (UHV) conditions.

[Clinical relevance and indications for cardiac magnetic resonance imaging 2013: an interdisciplinary expert statement]

During the last years the indications of Cardiac Magnetic Resonance Imaging (CMRI) have been continuously expanded. However, the acceptance of the method by cardiologists and radiologists does not correlate with respect to the diagnostic potential. Several factors, such as expensive equipment, relatively long examination times, high technical know how and lack of remuneration, limit the application of CMRI in everyday clinical practice. Furthermore, doctors tend to apply more conventional, well established diagnostic procedures, the access to the method is still limited and there exist difficulties in the interdisciplinary collaboration. The interdisciplinary Austrian approach to Cardiac Imaging is aimed to improve the aforementioned problems and to support the implementation of CMRI in the diagnostic tree of cardiac diseases thus enabling a cost efficient management of patients in cardiology.

Effect of abiraterone acetate plus prednisone on the pharmacokinetics of dextromethorphan and theophylline in patients with metastatic castration-resistant prostate cancer

PURPOSE

To assess the effect of abiraterone acetate plus prednisone on the pharmacokinetics of dextromethorphan HBr (CYP2D6 substrate) and theophylline (CYP1A2 substrate) in patients with metastatic castration-resistant prostate cancer (mCRPC).

METHODS

Men with progressive metastatic mCRPC who failed gonadotropin-releasing hormone therapy and ≥1 lines of chemotherapy were enrolled. Patients received two doses of dextromethorphan HBr-30 mg (n = 18; group A) or theophylline-100 mg (n = 16; group B) under fasting conditions; one dose on cycle 1, day -8, and the other dose on cycle 1, day 8. Only patients with extensive CYP2D6 metabolizing status were assigned to group A. All patients received continuous daily oral abiraterone acetate (1,000 mg) plus prednisone (10 mg) starting on cycle 1, day 1.

RESULTS

Coadministration of abiraterone acetate plus prednisone increased the systemic exposure of dextromethorphan by approximately 100%. Ratios of geometric means for maximum plasma concentration (C(max)) (275.36%) and area under plasma concentration-time curves from time 0 to 24 h (AUC(24h)) (268.14%) of dextromethorphan were outside the bioequivalence limit. The pharmacokinetics of theophylline was unaltered following coadministration of abiraterone acetate plus prednisone. Ratios of geometric means [C(max); 102.36% and AUC(24h); 108.03%] of theophylline exposure parameters were within the bioequivalence limit. The safety profile of abiraterone acetate was consistent with reported toxicities.

CONCLUSION

Abiraterone acetate plus prednisone increased the exposure of dextromethorphan, suggesting a need for caution when coadministrating with known CYP2D6 substrates. The pharmacokinetics of theophylline was unaffected when coadministered with abiraterone acetate plus prednisone.

Antagonism of the antithrombotic and anti-atherosclerotic actions of aspirin by rofecoxib in the cholesterol-fed rabbit

BACKGROUND AND PURPOSE

Most patients at elevated cardiovascular risk receive long-term aspirin (ASA) anti-platelet treatment. The present study specifically addresses the pharmacological interactions between selective COX-2 inhibitors and ASA and the possible consequences for the thrombotic risk during long-term treatment.

EXPERIMENTAL APPROACH

New Zealand white rabbits were fed a standard laboratory diet supplemented with 1% cholesterol (CON) for 12 weeks. Age-matched control rabbits were fed the same standard diet without addition of cholesterol (SD). Rabbits were randomly assigned to one of the following groups: rofecoxib (ROFE, 25 mg·kg⁻¹, bid), acetylsalicylic acid (ASA, 5 mg·kg⁻¹, bid) or a combination of both (ASA + ROFE). At the end of the feeding period, the severity of atherosclerotic plaque formation was assessed in the aorta. Thrombus formation was assessed in the left carotid artery using a modified Folts procedure.

KEY RESULTS

Treatment of cholesterol-fed rabbits with ASA significantly reduced plaque formation. This reduction in lesion size was not observed in animals treated with the combination of rofecoxib and ASA. In the modified Folts model, treatment with either rofecoxib or ASA increased the total blood flow above that of untreated animals. This increase was statistically significant in the case of ASA, while cotreatment with rofecoxib abolished this ASA effect completely and reduced the total flow rate to the levels seen in untreated hypercholesterolaemic controls.

CONCLUSIONS

COX-2 inhibition by rofecoxib attenuates the antithrombotic and anti-atherosclerotic effects of ASA during long-term treatment in cholesterol-fed rabbits.

Electromagnetic navigation bronchoscopy (ENB): Increasing diagnostic yield

OBJECTIVES

To determine factors associated with diagnostic yield of ENB.

METHODS

In 112 consecutive patients referred to our department between March 2010 and December 2010 the diagnostic work-up for solitary pulmonary lesions included a FDG-PET-CT scan, and ENB in combination with ROSE. The final diagnosis was confirmed by histopathological evaluation of specimen obtained either by ENB, or - if ENB was not diagnostic - by CT-guided fine needle aspiration or surgery.

RESULTS

Thirty-seven (33%) subjects were female, mean age was 66.7 (±1.04) years. The mean diameter of lesions was 27mm (range: 6-46mm). In 83.9% the combination of PET-CT, ENB, and ROSE established a correct diagnosis, as defined by the definite histopathological result. 15.2% (17/112) of lesions were benign, and 84.8% (95/112) were malignant. For 112 procedures we observed a steep learning curve with a diagnostic yield of 80% and 87.5% for the first 30 and last 30 procedures, respectively. The diagnostic yield in lesions ≤20mm and >20mm in diameter was 75.6% and 89.6% (p=0.06), respectively. No significant difference in diagnostic yield was seen depending on lung function, and the localization of the lesions. Two cases (1.8%) of pneumothorax were seen during and up to 24h after bronchoscopy, none of them required a chest tube.

CONCLUSION

Diagnostic yield increased with experience but was independent from the size of the lesion, the localisation in the lungs, and lung function. The diagnostic yield of ENB can be as high as for CT-guided transthoracic biopsies but carries a significantly lower complication rate.

An improved time-of-flight method for cluster deposition and ion-scattering experiments

A molecular beam apparatus has been developed for deposition and scattering experiments of size-selected clusters. The new setup combines a bimetallic laser ablation cluster source with a collinear time-of-flight mass spectrometer. Mass selection is achieved with a pulsed electrostatic mirror. A significantly improved transmission in combination with a reduction of the kinetic energy distribution of the mass selected clusters has been obtained. Without further modification of the apparatus, surface-induced dissociation of mass selected tin clusters has been investigated, demonstrating the possibility to combine cluster beam deposition and scattering experiments.

Ultrasonic force microscopy on strained antimony nanoparticles

Ultrasonic force microscopy (UFM) is used to resolve the elastic nanostructure of strained antimony (Sb) particles. These nanoparticles were formed by aggregation and spontaneous rapid crystallization of thermally deposited Sb onto the (0001) basal planes of highly oriented pyrolytic graphite (HOPG) and molybdenum disulfide (MoS(2)). UFM reveals clear contrast within individual nanoparticles, which can be attributed to differences in the local stiffness. This interpretation is confirmed by transmission electron microscopy (TEM) images, in which bending contours prove the existence of strained regions within the nanocrystals.

Farming and the prevalence of non-reversible airways obstruction: results from a population-based study

INTRODUCTION

Occupational exposure to noxious dusts, gases, and fumes most likely contributes to obstructive lung disease. We studied whether self-reported farming work is associated with non-reversible airways obstruction.

METHODS

Following the burden of obstructive lung disease (BOLD) study protocol, we surveyed a gender-stratified population-based sample of 2,200 adults aged 40 years and over. Pre- and post-bronchodilator spirometry, as well as information on smoking, occupation, and reported respiratory disease was recorded. According to GOLD criteria, non-reversible airways obstruction was defined as a post-bronchodilator forced expiratory volume (FEV(1))/forced vital capacity (FVC) < 0.70. Occupational and smoking history was based on questionnaire. Farming was defined as ever working in this occupation for 3 months or longer.

RESULTS

For 1,258 participants with complete data (post-bronchodilator spirometry and questionnaire data), 288 (=22.9%) reported farming. Among the 288 participants reporting farming, the prevalence of non-reversible airways obstruction was 30.2%. Farming was significantly associated with airways obstruction: chronic obstructive pulmonary disease (COPD) GOLD stage I or higher (OR 1.5; 95% CI 1.1-2.0) and COPD GOLD stage II or higher (OR 1.8; 95% CI 1.2-2.7). The latter estimate was unchanged when adjustment for competing risks gender, age, and smoking was done. In this population the risk for non-reversible airways obstruction attributable to farming was 7.7%.

CONCLUSION

Farming should be considered a risk factor for non-reversible airways obstruction.

Spinal leptomeningeal metastases from prostate cancer

OBJECTIVE

Prostate cancer is a well known cause of spinal column metastases; however, an intradural location is extremely rare. It is considered to be a type of leptomeningeal spread. Cerebral seeding has usually occurred by the time of presentation. Due to a poor prognosis, surgery is rarely indicated, and controversially discussed.

PATIENT AND RESULTS

We review the known cases of spinal leptomeningeal prostate cancer spread, including our patient, who developed paraparesis over 6 weeks, 3 years after prostate cancer was diagnosed. Following surgical decompression and resection, the patient additionally received radiation therapy of the spinal meninges and antihormonal treatment. 6 months after surgery, the patient is still ambulatory with a good quality of life.

CONCLUSION

Spinal leptomeningeal metastases occur at a late stage of systemic disease, and the prognosis is generally poor. In the literature, outcomes after surgery are reported as devastating, with mortality and morbidity rates of up to 20% and 60%. The aim of surgery is to relieve pain, preserve or even restore neurological function, and reveal histology if uncertain. This may be achieved by debulking the tumor without placing the patient at an unacceptably high risk. Surgery should be performed in selected cases of spinal leptomeningeal metastases, in patients who are still ambulatory with controlled systemic disease, and should be followed by adjuvant therapy.

Spinal Leptomeningeal Metastases from Prostate Cancer

OBJECTIVE

Prostate cancer is a well known cause of spinal column metastases; however, an intradural location is extremely rare. It is considered to be a type of leptomeningeal spread. Cerebral seeding has usually occurred by the time of presentation. Due to a poor prognosis, surgery is rarely indicated, and controversially discussed.

PATIENT AND RESULTS

We review the known cases of spinal leptomeningeal prostate cancer spread, including our patient, who developed paraparesis over 6 weeks, 3 years after prostate cancer was diagnosed. Following surgical decompression and resection, the patient additionally received radiation therapy of the spinal meninges and antihormonal treatment. Six months after surgery, the patient is still ambulatory with a good quality of life.

CONCLUSION

Spinal leptomeningeal metastases occur at a late stage of systemic disease, and the prognosis is generally poor. In literature, outcomes after surgery are reported as devastating, with mortality and morbidity rates of up to 20 and 60%. The aim of surgery is to relieve pain, preserve or even restore neurological function, and reveal histology if uncertain. This may be achieved by debulking the tumor without placing the patient at an unacceptably high risk. Surgery should be performed in selected cases of spinal leptomeningeal metastases, in patients who are still ambulatory with controlled systemic disease, and should be followed by adjuvant therapy.

Synthetic and recombinant antithrombin drugs

As the final enzyme in the activation of the coagulation system, the serine protease, thrombin, is believed to be an important target for the development of new anticoagulant/antithrombotic drugs. Direct thrombin inhibitors are either derived from natural sources, such as hirudin or are chemically synthesised, such as argatroban. The coupling of hirudin or parts of it with other entities leads to novel agents with different pharmacokinetic and pharmacodynamic characteristics, such as polyethylene glycol (PEG)-hirudin or the hirulogs. Due to the reversible or irreversible inactivation of the enzyme, thrombin inhibitors exert strong anticoagulant effects that can be measured in global clotting assays. Furthermore, these compounds inhibit thrombin-induced platelet reactions and influence other cellular, receptor-mediated actions of thrombin, e.g., on vascular cells. Directly acting thrombin inhibitors prevent blood clotting and are also capable of inhibiting clot-associated thrombin; however, they do not effectively block the further generation of the enzyme. Comprehensive experimental studies suggest that thrombin inhibitors may be effective drugs in a wide range of intravascular thrombus formation, also including the inhibition of vascular restenosis. Recent clinical trials revealed the effectiveness of direct thrombin inhibitors in various thrombotic and cardiovascular indications, but also a tendency to an increased risk of bleeding complications. At present, thrombin inhibitors are the most promising class of drugs for the initial therapy of patients with heparin-induced thrombocytopaenia (HIT) or the heparin-induced thrombocytopaenia and thrombosis syndrome (HITTS). They are also useful for the management of venous thrombosis and for acute ischaemic syndromes as well as for invasive procedures. However, with regard to the long-term outcome, a superiority of thrombin inhibitors over heparin has not yet been demonstrated. Several important issues, such as monitoring, pharmacological antagonism and drug interactions will also play an important role in the development of these new drugs. Further clinical trials are required to confirm the effectiveness of direct thrombin inhibitors in the prophylaxis and treatment of various thromboembolic and cardiovascular disorders.