A facile method for high-throughput screening of drug-eluting coatings in droplet microarrays based on ultrasonic spray deposition

Coating modification such as drug-eluting coating is one of the most important approaches for the functionalization of biomedical devices. However, the throughputs are limited in conventional coating methods and the concept of miniaturization is rarely fulfilled. A droplet microarray (DMA), as a unique high-throughput platform, can avoid cross-contamination and reduce the consumption of materials which is inherently suitable for coating research yet is difficult to apply with coating materials via traditional methods. Here, we bring up a facile method based on ultrasonic spray deposition to integrate coating materials into a DMA. Several common polymer materials were selected to fabricate a DMA, and the obtained DMA showed the ability to anchor water droplets and form specific patterns. Coating arrays with a typical sandwich structure were also prepared for the high-throughput screening of drug-eluting coatings to demonstrate the potential of the platform in coating research. This developed method is efficient and compatible and enriches the choices of materials that can be applied in DMAs.

Rapid build-up of high-throughput screening microarrays with biochemistry gradients via light-induced thiol-ene "click" chemistry

Microarrays have become extremely powerful experimental tools for high-throughput screening of cell behaviors in multivariate microenvironments. Herein, a microarray-based high-throughput platform with biochemistry gradients was developed using poly(limonene carbonate) (PLimC) as a substrate through thiol-ene click chemistry. ATR-IR, XPS, Raman spectrum, and water contact angle results demonstrated that the sulfhydryl molecules, including PEG (polyethylene glycol) and RGD (arginine-glycine-aspartic acid) peptide, could be grafted onto PLimC substrates, while the grafting density could be well controlled by regulating the intensity of UV irradiation. Then, microarrays with a gradient of RGD grafting density were fabricated by using UV irradiation patterned by a photomask and a gradient light filter. Adhesion experiments of smooth muscle cells and 3T3-L1 mouse embryonic fibroblast cells proved that the cell behaviors were highly determined by the RGD density. This platform puts forward a facile, high-throughput method to study the effect of biochemical signal density on cell behaviors.

Aortic aneurysm and aortic graft infection related to Mycobacterium bovis after intravesical Bacille Calmette-Guérin therapy-a case series

Background

So called “mycotic” aortic aneurysms account for only 0.7 to 1.3% of all aortic aneurysms and are commonly caused by Staphylococcus aureus and Salmonella species. Bacillus Calmette-Guérin (BCG), a live attenuated strain of Mycobacterium bovis, is part of the therapy of non-muscle-invasive bladder cancer (NMIBC).

Case presentation

We report a case series of three patients with a mycobacterial graft infection related to BCG after surgical treatment of a presumed mycotic aortic aneurysm as an extremely rare complication after NMIBC treatment. All three patients developed aortic aneurysm after BCG instillation and subsequent mycobacterial graft infection.

Conclusion

Diagnosis requires a high degree of suspicion because of its nonspecific symptoms and imaging. The pathogen is not detected by standard microbiological testing. Treatment includes triple antimycobacterial therapy and radical surgical interventions. Graft preservation may be considered if no anastomosis is involved.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12893-021-01142-1.

Environmental exposure enhances the internalization of microplastic particles into cells

Microplastic particles ubiquitously found in the environment are ingested by a huge variety of organisms. Subsequently, microplastic particles can translocate from the gastrointestinal tract into the tissues likely by cellular internalization. The reason for cellular internalization is unknown, since this has only been shown for specifically surface-functionalized particles. We show that environmentally exposed microplastic particles were internalized significantly more often than pristine microplastic particles into macrophages. We identified biomolecules forming an eco-corona on the surface of microplastic particles, suggesting that environmental exposure promotes the cellular internalization of microplastics. Our findings further indicate that cellular internalization is a key route by which microplastic particles translocate into tissues, where they may cause toxicological effects that have implications for the environment and human health.

A Family of Argonaute-Interacting Proteins Gates Nuclear RNAi

Nuclear RNA interference (RNAi) pathways work together with histone modifications to regulate gene expression and enact an adaptive response to transposable RNA elements. In the germline, nuclear RNAi can lead to trans-generational epigenetic inheritance (TEI) of gene silencing. We identified and characterized a family of nuclear Argonaute-interacting proteins (ENRIs) that control the strength and target specificity of nuclear RNAi in C. elegans, ensuring faithful inheritance of epigenetic memories. ENRI-1/2 prevent misloading of the nuclear Argonaute NRDE-3 with small RNAs that normally effect maternal piRNAs, which prevents precocious nuclear translocation of NRDE-3 in the early embryo. Additionally, they are negative regulators of nuclear RNAi triggered from exogenous sources. Loss of ENRI-3, an unstable protein expressed mostly in the male germline, misdirects the RNAi response to transposable elements and impairs TEI. The ENRIs determine the potency and specificity of nuclear RNAi responses by gating small RNAs into specific nuclear Argonautes.

Evaluation of urinary selenium as a biomarker of human occupational exposure to elemental and inorganic selenium

PURPOSE

Selenium (Se) is an essential trace element, which however, exhibits a narrow safe range of intake. Selenium also occurs at several workplaces, which results in an inhalative selenium exposure of the employees. Thus, an efficient exposure assessment strategy is demanded. The most established parameter, selenium in plasma, mostly consists of protein-bound selenium. This study aimed to investigate urinary total selenium (Se-U) as an additional biomarker of recent human occupational exposure to elemental and inorganic selenium.

METHODS

Pre- and post-shift urine samples from employees with exposure to selenium-containing dust were analyzed to total selenium and compared with Se levels in urine samples from controls without occupational exposure to selenium as well as correlated with the recent ambient Se exposure by personal air monitoring.

RESULTS

Se-U in post-shift samples was considerably increased compared to the levels in pre-shift samples as well as to the controls. However, Se-U in pre-shift urine was elevated compared to the Se-U in controls too. Se-U in post-shift urine and even better the shift increment in Se-U correlated with the air exposure of the present shift. A rough estimation by Se-U shift increment and external exposure accounted for an inhalative resorption rate of about 1%.

CONCLUSION

Our data indicate that Se-U can display the exposure. Pre-shift Se-U levels may be based on previous exposure and indicate a slow urinary elimination kinetics. The results hint for a rather low resorption rate of selenium and inorganic selenium compounds via the lung.

Urine neutrophil gelatinase-associated lipocalin predicts outcome and renal failure in open and endovascular thoracic abdominal aortic aneurysm surgery

Urine neutrophil gelatinase–associated lipocalin (uNGAL) has been evaluated as a biomarker for AKI detection and adverse outcome in open and endovascular thoracoabdominal aortic aneurysm surgery. This observational, retrospective study included 52 patients. UNGAL was measured peri-operatively (48 h) and correlated with AKI requiring dialysis, tracheotomy and adverse outcome. Mean patients’ age was 64.5 years. A total of 26.9% (n = 14) developed AKI, and 21.1% (n = 11) required dialysis, tracheotomy rate was 19.2% (n = 10) and in-hospital mortality rate was 7.6% (n = 4). uNGAL levels were related to AKI requiring dialysis at ICU (p = 0.0002), need for tracheotomy at baseline and admission on ICU (p = 0.0222, p = 0.0028, respectively), as well as adverse discharge modality (p = 0.0051, p = 0.0048, respectively). Diagnostic quality was good for uNGAL levels at admission to ICU regarding AKI requiring dialysis (sensitivity: 81.8% [48.2–97.7]; specificity: 87.8% [73.8–95.9]; area under the curve (AUC): 0.874 [0.752–0.949]). The diagnostic quality of uNGAL was favorable for the prediction of tracheotomy (sensitivity: 70.0% [34.8–93.3]; specificity: 83.3% [68.6–93.0]; AUC: 0.807 [0.674–0.903]) and adverse discharge (sensitivity: 77.8% [40.0–97.2]; specificity: 83.7% [69.3–93.2]; AUC: 0.817 [0.685–0.910]). uNGAL may be valuable as an post-operative predictor of AKI and adverse outcome after open and endovascular TAAA repair.

Targeting of Photoreceptor Genes in Chlamydomonas reinhardtii via Zinc-Finger Nucleases and CRISPR/Cas9

The fast-growing biflagellated single-celled chlorophyte Chlamydomonas reinhardtii is the most widely used alga in basic research. The physiological functions of the 18 sensory photoreceptors are of particular interest with respect to Chlamydomonas development and behavior. Despite the demonstration of gene editing in Chlamydomonas in 1995, the isolation of mutants lacking easily ascertained newly acquired phenotypes remains problematic due to low DNA recombination efficiency. We optimized gene-editing protocols for several Chlamydomonas strains (including wild-type CC-125) using zinc-finger nucleases (ZFNs), genetically encoded CRISPR/associated protein 9 (Cas9) from Staphylococcus aureus and Streptococcus pyogenes, and recombinant Cas9 and developed protocols for rapidly isolating nonselectable gene mutants. Using this technique, we disrupted the photoreceptor genes COP1/2, COP3 (encoding channelrhodopsin 1 [ChR1]), COP4 (encoding ChR2), COP5, PHOT, UVR8, VGCC, MAT3, and aCRY and created the chr1 chr2 and uvr8 phot double mutants. Characterization of the chr1, chr2, and mat3 mutants confirmed the value of photoreceptor mutants for physiological studies. Genes of interest were disrupted in 5 to 15% of preselected clones (∼1 out of 4000 initial cells). Using ZFNs, genes were edited in a reliable, predictable manner via homologous recombination, whereas Cas9 primarily caused gene disruption via the insertion of cotransformed DNA. These methods should be widely applicable to research involving green algae.

IKZF1 expression is a prognostic marker in newly diagnosed standard-risk multiple myeloma treated with lenalidomide and intensive chemotherapy: a study of the German Myeloma Study Group (DSMM)

Lenalidomide is an immunomodulatory compound with high clinical activity in multiple myeloma. Lenalidomide binding to the Cereblon (CRBN) E3 ubiquitin ligase results in targeted ubiquitination and degradation of the lymphoid transcription factors Ikaros (IKZF1) and Aiolos (IKZF3) leading to growth inhibition of multiple myeloma cells. Recently, Basigin (BSG) was identified as another protein regulated by CRBN that is involved in the activity of lenalidomide. Here, we analyzed the prognostic value of IKZF1, IKZF3, CRBN and BSG mRNA expression levels in pretreatment plasma cells from 60 patients with newly diagnosed multiple myeloma uniformly treated with lenalidomide in combination with intensive chemotherapy within a clinical trial. We found that IKZF1 mRNA expression levels are significantly associated with progression-free survival (PFS). Patients in the lowest quartile (Q1) of IKZF1 expression had a superior PFS compared with patients in the remaining quartiles (Q2-Q4; 3-year PFS of 86 vs 51%, P=0.01). This translated into a significant better overall survival (100 vs 74%, P=0.03). Subgroup analysis revealed a significant impact of IKZF1, IKZF3 and BSG expression levels on PFS in cytogenetically defined standard-risk but not high-risk patients. Our data suggest a prognostic role of IKZF1, IKZF3 and BSG expression levels in lenalidomide-treated multiple myeloma.

Bio-based polycarbonate as synthetic toolbox

Completely bio-based poly(limonene carbonate) is a thermoplastic polymer, which can be synthesized by copolymerization of limonene oxide (derived from limonene, which is found in orange peel) and CO2. Poly(limonene carbonate) has one double bond per repeating unit that can be exploited for further chemical modifications. These chemical modifications allow the tuning of the properties of the aliphatic polycarbonate in nearly any direction. Here we show synthetic routes to demonstrate that poly(limonene carbonate) is the perfect green platform polymer, from which many functional materials can be derived. The relevant examples presented in this study are the transformation from an engineering thermoplastic into a rubber, addition of permanent antibacterial activity, hydrophilization and even pH-dependent water solubility of the polycarbonate. Finally, we show a synthetic route to yield the completely saturated counterpart that exhibits improved heat processability due to lower reactivity.

[The Compression Syndrome of Lumbar Arteries - Case Report of a Rare Disease Pattern]

STUDY DESIGN

We present a monocentric analysis of the lumbar artery compression syndrome (LACS) in the form of a case report.

OBJECTIVES

Literature information was collected about the symptoms, diagnosis and treatment of this rare disorder in the context of the existing data.

METHODS

The current medical literature includes only one report about three cases of LACS, collected over 20 years in France and Germany. We compared these cases with the experience of the European Vascular Center Aachen-Maastricht.

RESULTS

The symptoms of this rare disorder are dominated by reversible, motion-dependent paralysis of the legs. Compression of the right lumbar arteries by muscular fibres or connective tissue is a fundamental cause.

CONCLUSION

Surgical treatment, which means decompression of the lumbar arteries via a thoracolaparotomy, is an appropriate therapy with few complications and good long-term results.

What predicts outcome after recanalization of chronic venous obstruction: hemodynamic factors, stent geometry, patient selection, anticoagulation or other factors?

In this review we evaluated the effect of different suggested factors associate with the outcome after recanalization of chronic venous obstruction (CVO).

Hemodynamic factors:

Based upon literature no clear suggestions can be made to identify the risk of stent occlusion in association with the hemodynamic effects. However it is evident that ensuring optimal in- and outflow of the stented tract is key in maintaining the patency.

Patient selection:

Noninvasive imaging modalities are used to divide patients in three subgroups based on the place and extension of post-thrombotic changes. Moreover it should be noted that AV fistula in selected patients can reduce the risk of thrombosis or re-occlusion.

Geometry:

Excessive oversizing of the stent and stent compression from outside are considered to be associated with stent occlusion. Additionally, overlapping rigid stents, unnatural angel between stents and in-stent kinking are other geometrical factors related to worse outcome after venous recanalization.

Anticoagulation:

Adequate peri-and postoperative anticoagulation has a crutial role in stent patency. There is no data regarding the duration of anticoagulation therapy and recommendations vary between 6 weeks to 6 months.

Result:

impaired inflow or outflow, presence of a hypercoagulability, total number of treated segments and use of stents designed for implantation in arterial system are associated with decreased stent patency.

Anatomic changes of target vessels after fenestrated and branched aortic aneurysm repair

AIM

Objective of this study was to evaluate the anatomic changes of the stented target vessels after endovascular repair of complex aortic aneurysms.

METHODS

Between July 2011 and December 2013, 53 aortic aneurysms were treated in our department with fenestrated and branched stent-graft devices. Forty-two of these patients were pre- and postoperatively scanned with a high resolution computer tomography (CT) (Cook Zenith® fenestrated or branched, Australia Pty. Ltd., Brisbane, Australia: N.=19; AnacondaTM fenestrated, Vascutek, Glasgow, Scotland, UK: N.=23). The other 11 out of the 53 patients did not receive a CT scan, because of a pre-existing renal failure. In the CT scans we retrospectively evaluated the anatomic vessel deviation at the origin of the target vessel and the vessel shift distal to the stent. For the first measurement the CT scans were loaded into OsiriX MD®, and the pre- and postoperative angles of the target vessels were measured and subtracted. For matching, the CT-scans were normalized at vertebral body lumbar 2. The second measured angle was the maximal measured angle distal to the target vessel stent-graft.

RESULTS

Altogether, 113 target vessels were stented (celiac trunk [CT] 15, superior mesenteric arteries [SMA] 26, renal arteries [RA] 72), with 97 balloon-expandable PTFE stents: 90 Atrium V12 (Maquet Getinge group, Hudson, NH, USA), 7 BeGrafts (Bentley InnoMed, Hechingen, Germany) and 16 self-expandable fluency PTFE stents (Bard, Karlsruhe, Germany). The mean anatomic deviation at the target vessel origin was 28±17.3 and the mean vessel shift distal to the stent was 36.3±18.8. There were no significant differences between the main device and the target vessel stent types.

CONCLUSION

Fenestrated and branched stent-graft solutions for aortic aneurysm repair induce changes of the target vessel anatomy. We did not observe significant differences between the several devices.

A new shunting concept to prevent lower limb ischemia/reperfusion injury in prolonged fenestrated stent-graft procedures

AIM

Complex endovascular procedures to treat thoracoabdominal aortic aneurysms (TAAA) can be time consuming and therefore comprise the risk of lower limb ischemia with subsequent reperfusion injury and compartment syndrome. Aim of this study was to evaluate a new protective method to prevent these postoperative problems.

METHODS

In order to maintain blood perfusion to both legs during prolonged endovascular aortic procedures we developed a shunting technique with two additional 7 French (Fr) sheaths in both superficial femoral arteries. We evaluated the perfusion technique in 5 patients with fenestrated endovascular aortic aneurysms repair (FEVAR). First, we measured the flow in the 7 Fr sheaths; second, we clinically controlled the lower limb for developing compartment syndrome. Third we measured creatinine kinase (CK) as marker for postoperative muscular damage.

RESULTS

In 5 male patients (median age 77, range 59-80 years) undergoing endovascular TAAA repair, the perfusion technique was feasible. The median flow per catheter was 102 mL/min (range 61-156.5 mL/min) and monophasic with a mean arterial blood pressure of 71 mmHg (range 56-82 mmHg). No patient developed a compartment syndrome. The CK levels were only lightly elevated.

CONCLUSION

This simple perfusion technique allows adequate lower limb perfusion during prolonged complex endovascular aortic procedures.

Late rupture after EVAR: a new trend?

AIM

Endovascular aortic repair (EVAR) is an adequate therapy for abdominal aortic aneurysms (AAA). Late aortic ruptures caused by endoleaks after EVAR still remain a critical issue. The aim of this study was to assess the causes of ruptured aortic aneurysms after EVAR in a single center study.

METHODS

All patients, who were treated in our University hospital with a ruptured juxtra- or infrarenal AAA between January 2011 and October 2013, were included in this retrospective analysis.

RESULTS

Thirty patients with ruptured infra- or juxtrarenal aneurysms were treated in this time frame. Six out of these 30 patients had previous EVAR repair. The median maximal aneurysm diameter of these post-EVAR patients was 82 (75-95) mm. The median time between primary EVAR and rupture was 42.5 (14-99) months. Three patients with type Ia endoleaks were treated by stent removal and conventional aortic reconstruction. In two patients with type II endoleak the bleeding was controlled by occluding the back bleeding lumbar arteries. One type III endoleak was sealed by an additional stent-graft implantation into the right iliac artery.

CONCLUSION

We observed a considerable number of patients with a ruptured AAA after EVAR. Surprisingly, we observed two ruptured aneurysms due to type II endoleaks.

Nuclear gene targeting in Chlamydomonas using engineered zinc-finger nucleases

The unicellular green alga Chlamydomonas reinhardtii is a versatile model for fundamental and biotechnological research. A wide range of tools for genetic manipulation have been developed for this alga, but specific modification of nuclear genes is still not routinely possible. Here, we present a nuclear gene targeting strategy for Chlamydomonas that is based on the application of zinc-finger nucleases (ZFNs). Our approach includes (i) design of gene-specific ZFNs using available online tools, (ii) evaluation of the designed ZFNs in a Chlamydomonas in situ model system, (iii) optimization of ZFN activity by modification of the nuclease domain, and (iv) application of the most suitable enzymes for mutagenesis of an endogenous gene. Initially, we designed a set of ZFNs to target the COP3 gene that encodes the light-activated ion channel channelrhodopsin-1. To evaluate the designed ZFNs, we constructed a model strain by inserting a non-functional aminoglycoside 3'-phosphotransferase VIII (aphVIII) selection marker interspaced with a short COP3 target sequence into the nuclear genome. Upon co-transformation of this recipient strain with the engineered ZFNs and an aphVIII DNA template, we were able to restore marker activity and select paromomycin-resistant (Pm-R) clones with expressing nucleases. Of these Pm-R clones, 1% also contained a modified COP3 locus. In cases where cells were co-transformed with a modified COP3 template, the COP3 locus was specifically modified by homologous recombination between COP3 and the supplied template DNA. We anticipate that this ZFN technology will be useful for studying the functions of individual genes in Chlamydomonas.

Intentional left subclavian artery coverage without revascularization during TEVAR

At present, endovascular therapy is a well-established treatment for different types of thoracic aortic pathologies. There is growing evidence, that thoracic endovascular aortic repair (TEVAR) has advantages over open repair with regard to perioperative morbidity and mortality in the treatment of thoracic aortic aneurysms. However, in up to 50% of TEVAR procedures the proximal end of the stent-graft will (partly) cover the origin of the left subclavian artery (LSA) in order to achieve a save sealing zone. Intracranial stroke and paraplegia are feared complications and might be associated with LSA exclusion from the circulation. Unfortunately, no reliable technique is available to assess the individual risk of stroke and paraplegia in case of LSA coverage, so that the indication for LSA revascularization continues to be matter of assuming and guessing. The quality of available evidence on necessity or superfluity to revascularize the LSA is very low and studies report, to some extent, controversial outcome after intentional LSA coverage. In the light of the devastating consequences for patients in case of neurological complications due to LSA coverage the question of prophylactic LSA revascularization remains a significant problem which is elucidated and discussed in this manuscript.

Thoracoabdominal aneurysms and changes in adjacent vertebral bodies

AIM

The aim of this study was to assess if chronic intermittent pressure of a thoracoabdominal aortic aneurysm (TAAA) induces structural changes in vertebral bodies and if eroded vertebral bones can still be found after the extermination of syphilis.

METHODS

A retrospective analysis of computed tomography (CT) scans of patients with TAAA was performed. In the anatomical regions were the TAAA was in close contact with the vertebral bodies, the vertebral body alteration was distinguished into 4 categories. Category 0: no changes; 1: discrete changes, minimal asymmetry; 2: obvious asymmetry of the vertebral body with sustained cortical layer; 3: severe destruction of the vertebral body with loss of the cortical layer.

RESULTS

Eighty-six CT scans of patients (mean age 63; range 25-82 years) with TAAA pathology were examined (24 female, 62 male). The mean aneurysm diameter was 6.5 cm (4.3-14 cm). The results for scoring were: category 0: 33 patients; category 1: 46 patients; category 2: 5 patients and category 3: 2 patients. One of the category 3 patients suffered from acute spinal cord compression with complete paraplegia. In total, 62% of patients showed some degree of changes at vertebral bodies adjacent to the TAAA.

CONCLUSION

Intermittent pressure by either dissecting or non-dissecting TAAAs may induce structural changes in the vertebral bodies of the spine. Severe destruction of the bone is a rare, but existing complication.

[Aortic aneurysm 2012: open, hybrid or total endovascular repair?]

During the past two decades, minimally invasive endovascular procedures have changed therapeutic strategies. Such techniques have now become the method of choice for practically all vascular and aortic pathologies. This development is especially apparent in the treatment of aortic aneurysms. The purpose of this report is to provide a critical review about the current standard of care of abdominal and thoracic aorta based on an electronic Medline literature search. For elective infrarenal aneurysms, endovascular aneurysm repair (EVAR) has become a widely accepted alternative to open repair in cases with appropriate morphology. Currently, fenestrated (FEVAR) or branched endografts offer promising short- and mid-term results in juxtarenal aneurysms, however, these techniques are complex, technically challenging, and expensive. The alternative chimney or sandwich graft technique are becoming more common because they are feasible using standard endografts. Thoracic endovascular aortic repair (TEVAR) is already the gold standard for some descending pathologies. Complex thoracoabdominal aneurysms still require open surgery in centres of excellence, whereby, total endovascular repair or hybrid procedures have proved to be feasible in such specialist centres for selected patients.

Phototropin influence on eyespot development and regulation of phototactic behavior in Chlamydomonas reinhardtii

The eyespot of Chlamydomonas reinhardtii is a light-sensitive organelle important for phototactic orientation of the alga. Here, we found that eyespot size is strain specific and downregulated in light. In a strain in which the blue light photoreceptor phototropin was deleted by homologous recombination, the light regulation of the eyespot size was affected. We restored this dysfunction in different phototropin complementation experiments. Complementation with the phototropin kinase fragment reduced the eyespot size, independent of light. Interestingly, overexpression of the N-terminal light, oxygen or voltage sensing domains (LOV1+LOV2) alone also affected eyespot size and phototaxis, suggesting that aside from activation of the kinase domain, they fulfill an independent signaling function in the cell. Moreover, phototropin is involved in adjusting the level of channelrhodopsin-1, the dominant primary receptor for phototaxis within the eyespot. Both the level of channelrhodopsin-1 at the onset of illumination and its steady state level during the light period are downregulated by phototropin, whereas the level of channelrhodopsin-2 is not significantly altered. Furthermore, a light intensity-dependent formation of a C-terminal truncated phototropin form was observed. We propose that phototropin is a light regulator of phototaxis that desensitizes the eyespot when blue light intensities increase.

Primary and secondary amputation in critical limb ischemia patients: different aspects

The TASC II working group reports on primary amputation incidence rates vary between 12 and 50 per 100,000 per year. The primary amputation rate does not only depend on co-morbidities like diabetes and PAD, but also on local factors like the regional availability of vascular surgeons and interventional radiologists and their case load. Further-more, several studies could show that increasing revascularisation rates have drastically reduced amputation rates in the US, with a 50% decrease in amputation rates during a 10 year study period and a corresponding increase in surgical and endovascular revascularisation rates. An analysis of national and state US databases confirmed a drop in major amputations and open surgical revascularisations, in favour of an increase in endovascular interventions. The same study observed an increase in minor amputations during the same period. However, it remains unclear whether this trend is a consequence of the increased usage of endovascular procedures in high-risk patients who are unfit for open surgery or of earlier endovascular intervention in less critical lesions. This review gives an overview of the incidence, indication, amputation-level finding and outcome of major amputations performed in critical limb ischemia (CLI) patients.

Reliability of constant-load treadmill testing in patients with intermittent claudication

AIM

Constant-load treadmill testing is frequently used to estimate walking ability of patients with peripheral arterial disease and to assess changes in functional capacity following therapeutic interventions or through disease progression. The value of this test has frequently been disputed based on doubts concerning its reproducibility. The aim of this study was to investigate the reliability of treadmill testing at a speed of 3 km/h and a constant inclination of 12%.

METHODS

Sixty-eight patients with stable peripheral arterial disease who were familiar with treadmill testing underwent two sessions of walking exercise at 3 km/h and 12% inclination within three weeks. Initial claudication distance (ICD) and maximum walking distance (MWD) on the treadmill as well as reported walking distances on level ground at individual speed were recorded.

RESULTS

Correlation coefficients of 0.8 and within-subject variation coefficients of 15% for ICD and 13% for MWD demonstrated low variability of walking distances between visits. No learning effects were observed. Intra-class correlation coefficients of 0.78 for ICD and 0.83 for MWD proved good reproducibility of treadmill testing. Correlation of measured and reported walking distances was poor.

CONCLUSION

Constant-load treadmill testing at 3km/h and 12% inclination is a well reproducible method to investigate walking capacity of patients with stable intermittent claudication who are familiar with this test method. From treadmill walking distances, no conclusions should be drawn concerning the actual walking range of the patient.

Technical challenges and anatomic anomalies encountered during aortic surgery

Since the introduction of endovascular techniques for the treatment of aortic pathologies, clinical application of these lesser invasive procedures has increased exponentially during the last two decades and changed daily vascular practice completely. Starting in the infra-renal aorta, the indications for endovascular repair have gradually extended to the suprarenal aorta, aortic arch, descending and thoracoabdominal aorta. In addition, other pathologies than aneurysms have been treated by endovascular means, including dissection, traumatic injuries, penetrating aortic ulcer, intramural hematoma and aorto bronchial fistula. With increased application, short-term and longer-term technical failures have developed, in the majority of cases managed by repeat endovascular techniques. However, these complications cannot always be solved by endotechniques, requiring conversion to open surgery. At present there are additional reasons why open surgical repair remains a mainstay in the treatment of complex aortic diseases. Younger patients might choose for traditional surgery because of the unknown durability of complex endovascular reconstructions. Patients with connective tissue disease suffer from vulnerable aortic tissue in which endografts might behave different as compared to degenerative aneurysms. Therefore, the modern vascular surgeon should not only be trained in endovascular procedures but also master the wide spectrum of open surgical techniques. Besides anatomical knowledge and standard vascular handling, the surgeon must be familiar with unusual variations and unexpected situations.

XANES Studies at N and C K-Edge of Compounds in the Ternary System Si-C-N

We report on XANES-investigations at the nitrogen and carbon K-edge of Si-C-N containing solid phases prepared by the reaction of silicon tetrachloride with bis(trimethylsilyl)carbodiimide and annealing the reaction product at temperatures between room temperature (RT) and 1600°C. From the spectra it is possible to evidence the evolution of four phase regions and their different structural increments. We can relate the observed changes of atomic excitations to chemical and structural effects. By that means proposed structural models for the different phases are testified.

Organic electrospun nanofibers as vehicles toward intelligent pheromone dispensers: characterization by laboratory investigations

Organic nanofibers have a history of technical application in various independent fields, including medical technology, filtration technology, and applications of pharmaceuticals via inhalation into the lungs. Very recently, in a joint effort with polymer chemists, agricultural applications have been added to this list of priorities. The aim is finding novel approaches to insect control. Pheromones, dispensed in a quantifiable way, are being used here in disrupting the mating communication between male and female pest insects, e.g. the European grapevine moth Lobesia botrana (Lepidoptera: Tortricidae), where current dispenser technology does not fully meet the high expectations of growers and environmentalists with respect to longevity of constant release, self decomposition, mechanical distribution, renewability as well as sustainability of resources. The methodology of electrospinning is exhaustively covered by Greiner and Wendorff (2007), with technical details reported by Hellmann et al. (2009), Hein et al. (2011), and Hummel et al. (2010). Wind tunnel studies were run within a tunnel with adjustable laminar flow and 0.5 m/sec air velocity. Mass losses of the electrospun fiber bundles were determined with a sensitive analytical balance 2-3 times per week and recorded as time vs. mass change. CLSA experiments were performed with a self developed glass apparatus (Lindner, 2010) based on various suggestions of previous authors. Microgram quantities of volatile pheromone (E,Z)-7,9-Dodecadienylacetate were absorbed on a filter of rigorously purified charcoal and desorbed by repeated micro extraction with a suitable solvent mixture. Aliquots of the solution were subjected to temperature programmed capillary GLC. Retention times were used for identification, whereas the area covered by the pheromone peak originating from a FID detector signal was integrated and compared with a carefully calibrated standard peak. Since these signals were usually in the low nanogram range, several replications were averaged for statistical improvement. - Thermogravimetric analysis between ambient temperature and 500 degrees C provided a series of degradation curves where the diagram contained information on the evaporation of pheromone alone, polymer fiber alone and pheromone included in the fiber.- Microscopic investigations resulted in pictures of nanofibers from which the overall morphology and the fiber dimensions could be quantified. Organic nanofibers loaded with the grapevine moth pheromone have been well characterized by 5 different lab methods, followed by field bioassays reported elsewhere in these communications volumes (HUMMEL et al., 2011). This comprehensive analytical approach to fiber characterization is new and will be further refined. The federal agency JKI Berlin subjected the pheromone loaded organic fibers to various independent toxicological and ecotoxicological tests and found no adverse side effects.

Organic nanofibers containing insect pheromone disruptants: a novel technical approach to controlled release dispensers with potential for process mechanization

Beginning fifty years ago, the search for suitable dispensers containing insect pheromones grew with the availability of these synthetic biotechnical tools. Many economic entomologists and application engineers dearly wish they had the "smart, intelligent and ideal dispenser". More or less suitable approximations are available commercially, but none so far meets all demands. Under economic strictures, novel inexpensive systems would be advantageous with release characteristics tailored to the specific life histories of pest insects, the plants considered and the numerous requirements of growers alike. Simultaneously, their field distribution should be mechanizable and be accomplished by one (or very few) application runs. The dispensers should be biodegradable, biocompatible, sustainably applicable, and they should be based on renewable resources. This report presents first results of a novel organic, electrospun nanofiber dispenser with dimensions in the upper nanometer range. Its load of pheromone can be adjusted to be sufficient for 7 weeks of constant disruptive action in vineyards and can be directed against the European Grape Vine Moth Lobesia botrana (Lepidoptera: Tortricidae) which here serves as a readily available model. Mating disruption in L. botrana and the related Eupoecilia ambiguella is a well studied and developed engineering process. Equally, nanofiber production by electrospinning (for a comprehensive review see Greiner and Wendorff, 2007A, B) is well known and already has numerous applications in filtration technology, air conditioning, and medical wound dressing. Our goal was to bring together and successfully mate these (partly incompatible) technologies via technical tricks of a proprietary nature. Even though the lifetime and effectiveness of currently available nanofibers still must be doubled, the rather complicated system of their production and analysis is known well enough to identify the parameters that need future adjustment. Another challenge is the mechanical distribution of the fibers in the vineyards by suitable machinery. Also, in this respect, certain technical leads are available for future development.

Angiography catheter based bleeding complication at the access site related to neurofibromatosis I

Neurofibromatosis Type I (NF-I) is one of the most common inherited human diseases with an incidence of 1/3000. Besides the cardinal features, all organs or body structures as well as several arterial regions can occasionally be affected. We present an unusual case of an access-site hematoma following percutaneous transluminal coronary angioplasty in a patient suffering from NF-1. After exposure of the vessels, excessive bleeding from surrounding proliferations of supposedly neurofibromatous or ganglioneuromatous tissue was identified as the sole source of the hematoma. Patients with neurofibromatosis are at considerable risk of obtaining catheter interventions over the years. In this group, we strongly recommend an ultrasound examination of the arterial segment where the arterial access is planned. In case of suspicious findings an alternative approach should be preferred to avoid bleeding complications.

[Intraoperative neuromonitoring for prevention of neurological complications in aortic surgery]

AIM

Stroke and paraplegia are devastating complications of thoracic and thoracoabdominal aortic surgery. The aim of this study was to analyse the value of transcranial Doppler ultrasound (TCD), electroencephalogram (EEG) and motor-evoked potentials (MEP) in preventing neurological complications. Moreover, the principles, technology and surgical protocols are described.

PATIENTS AND METHODS

In 2009, 22 patients (4 females, 18 males) underwent thoracic or thoracoabdominal open aortic repair. We performed 2 arches with descending aortic replacement, 5 arches with TAAA repair, 2 type II, 9 type III, 3 type IV and one type V TAAA aortic repair. In 6 patients, the neuromonitoring included TCD, EEG and MEPs. In 15 patients only MEP monitoring was necessary. In one patient who was operated on in an emergency setting, neuromonitoring was not performed. The surgical approach was a left thoracotomy in 3 and a left thoracolaparotomy in 19 patients. The surgical protocol included cerebrospinal fluid drainage (n=22), moderate (n=19) or deep hypothermia (n=2), and extracorporeal circulation (n=21) with retrograde aortic perfusion and selective cerebral and/or viscerorenal perfusion.

RESULTS

In 21 patients, the neuromonitoring could be established successfully. Using TCD and EEG, a relevant cerebral ischaemia during supraaortic clamping was excluded. With a mean distal arterial pressure of 60 mmHg, the MEPs remained adequate in 15 patients (68.2%). Increasing of the blood pressure restored the MEPs in one patient. In 5 patients (22.7%), a reimplantation of segmental arteries (n=4) or of the left subclavian artery (n=1) re-established spinal cord perfusion, as indicated by restored MEPs. We had no absent MEPs at the end of the procedures. Delayed paraparesis developed in 2 patients with a haemodynamic instability during the postoperative course. Paraplegia was not observed.

CONCLUSION

TCD, EEG and MEPs are reliable techniques to unmask cerebral or spinal cord ischaemia during aortic surgery. Immediate operative strategies based on neuromonitoring information prevent neurological complications in aortic surgery.

Marfan Syndrome: when to operate TAA(A)s?

Marfan Syndrome is a heritable disorder of connective tissue leading to aortic aneurysms and other cardiovascular complications associated with reduced life expectancy. Marfan patients with thoracic aortic aneurysms (TAAs) or with thoracoabdominal aortic aneurysms (TAAAs) should be treated by means of open surgery, requiring an extensive protocol, including extracorporeal circulation, neuromonitoring and adjunctive modalities to provide organ protection. Then, open surgical repair of TAA(A)s are associated with excellent results. However, in the last time a gradual change to endovascular treatment in Marfan patients is observable. Particularly in patients with an increased surgical risk due to redo sternotomy or thoracotomy, endovascular treatment might be an alternative due to its less invasive approach. Consequently, thoracic endovascular aortic repair comprises a therapeutic alternative in individual situations even in Marfan patients, when the landing zones are safe and appropriate. In cases of failed endovascular therapy, however, conversion to open surgery remains still an option with acceptable results, although the distal and proximal clamping positions change inappropriate with larger extensions due to the aortic stent.

[Retroperitoneal bronchogenic cyst treated by laparoscopic surgery]

The diagnosis of primary retroperitoneal cystic tumors is very infrequent in surgical pathology. We report the case of a 51-year-old woman presenting with an incidental left-sided retroperitoneal mass (32 x 24 mm in diameter) suspected of being an adrenal tumor. Intraoperatively the tumor was identified as a cystic lesion filled with mucous secretion and laparoscopically completely resected. The diagnosis was histopathologically confirmed as a bronchogenic cyst. In this article the laparoscopic removal of such a rare benign congenital aberration resulting from an abnormal budding of the tracheobronchial tree is presented.

Pancreatic graft survival despite partial vascular graft thrombosis due to splenocephalic anastomoses

Thrombotic complications following pancreas transplantation are still the most common cause of nonimmunologic graft loss. The aim of this study was to analyze pancreatic graft function after partial arterial graft thrombosis and the investigation of the pancreatic arterial anatomy with regard to intraparenchymal anastomoses. We retrospectively analyzed the data for 175 consecutive pancreas transplants performed between January 2002 and October 2007. Selective Y-graft angiography was performed in 10 and rubber-milk injection in 5 fresh pancreas specimens. Thrombosis of one leg of the Y-graft was diagnosed in 18 (10.3%) patients. Only one of these patients with thrombosis of the splenic artery required exogenous insulin. Sufficient graft perfusion was demonstrated in all of the remaining grafts. One graft was lost due to acute rejection. In all specimens angiography showed an excellent perfusion of the pancreaticoduodenal arcade, even after selective cannulation of the splenic artery. Arterial collaterals between the gastroduodenal, splenic artery and the superior mesenteric artery were demonstrated. Our results demonstrate that global perfusion of the pancreatic graft and sufficient graft function is sustained after the thrombotic occlusion of one branch of the Y-graft by a complex system of intraparenchymal anastomoses. These anatomical findings may have consequences for resection strategies in pancreas surgery.

Lack of obvious influence of PLLA nanofibers on the gene expression of BMP-2 and VEGF during growth and differentiation of human mesenchymal stem cells

Growth factors like bone morphogenetic protein 2 (BMP-2) and vascular endothelial growth factor (VEGF) play an important role in bone remodeling and fracture repair. Therefore, with respect to tissue engineering, an artificial graft should have no negative impact on the expression of these factors. In this context, the aim of this study was to analyze the impact of poly(L-lactic acid) (PLLA) nanofibers on VEGF and BMP-2 gene expression during the time course of human mesenchymal stem cell (hMSC) differentiation towards osteoblasts. PLLA matrices were seeded with hMSCs and cultivated over a period of 22 days under growth and osteoinductive conditions, and analyzed during the course of culture, with respect to gene expression of VEGF and BMP-2. Furthermore, BMP-2–enwoven PLLA nanofibers were used in order to elucidate whether initial down-regulation of growth factor expression could be compensated. Although there was a great interpatient variability with respect to the expression of VEGF and BMP-2, PLLA nanofibers tend to result in a down-regulation in BMP-2 expression during the early phase of cultivation. This effect was diminished in the case of VEGF gene expression. The initial down-regulation was overcome when BMP-2 was directly incorporated into the PLLA nanofibers by electrospinning. Furthermore, the incorporation of BMP-2 into the PLLA nanofibers resulted in an increase in VEGF gene expression. Summarized, the results indicate that the PLLA nanofibers have little effect on growth factor production. An enhancement in gene expression of BMP-2 and VEGF can be achieved by an incorporation of BMP-2 into the PLLA nanofibers.