Search

Limb-threatening ischemia is one of more important problem of fundamental and practice modern angiology. Despite the development of modern diagnostic and therapeutic approaches good results, Limb-Threatening Ischemia deserves special attention and occupies a special place among medical, biomedical and socio-economic problems. A comprehensive study will make it possible to develop new approaches, the result of which should be a decrease in the total number of diseases, as well as a minimization of complications leading to large-scale tissue losses and amputations. We set out to develop a new non-invasive method for studying microcirculation in patients with limb-threatening ischemia. We investigated control group and adults of both sexes (age: 50–75 years) with a confirmed diagnosis of the claudication. Men and women in ratio 1 : 1 in control and target groups. The research results showed that the original microcirculation coefficient calculated according to our algorithm in patients with intermittent claudication was 70% better than in the control group and 120% of patients were worse than in patients with Limb-Threatening Ischemia. Our research team created an original so called coefficient of microcirculation. In order to determine it, we studied the blood flow in the pulsations on the left and right side of the posterior tibial arteries of the legs at rest (names of lines SIN F, DEX F) and during post-ischemic hyperemia in the same lines. The study of microcirculation based on the microcirculation coefficient is very informative. The importance of this methodology for studying the total peripheral blood flow and arteriolar response is due to fundamental and clinical developments, as well as financial costs. Considering the technique described in the article can be easily mastered by medical personnel, it is easy to use in the inpatient and outpatient sectors, its use does not require large areas of the medical facility, the equipment is not expensive and the test itself does not cause inconvenience to the patient, then we can recommend including the described method is included in the list of functional diagnostic tests as a direct and quantitative method for determining microcirculation (without special costs on the part of medical institutions, insurance companies and the patient).

The cyanobacterium Arthrospira platensis is a well-known source of bioactive substances. Growth and the generation of bioactive ingredients of Arthrospira platensis depend mainly on the quantity of light in a controlled environment. Photoinhibition is a time, nutrient, and light intensity-dependent decrease in photosynthetic efficiency. However, too strong illumination can induce two harmful effects: (1) photoinhibition as a reduction in photosynthetic rate and (2) photooxidation which can have lethal effects on the cells, and which can lead to total loss of the culture. The results of this microscopical study demonstrate, that under the procedures described and very high photon flux den-sities, not only a decrease in the photosynthetic efficiency but beyond, also destruction of Arthrospira platensis can occur.

The establishment of confluent endothelial cell (EC) monolayers on implanted materials has been identified as a concept to avoid thrombus formation but is a continuous challenge in cardiovascular device engineering. Here, material properties of gelatin-based hydrogels obtained by reacting gelatin with varying amounts of lysine diisocyanate ethyl ester were correlated with the functional state of hydrogel contacting venous EC (HUVEC) and HUVEC’s ability to form a monolayer on these hydrogels. The density of adherent HUVEC on the softest hydrogel at 37 °C (G’ = 1.02 kPa, E= 1.1 ± 0.3 kPa) was significantly lower (125 mm–1) than on the stiffer hydrogels (920 mm–1; G’ = 2.515 and 5.02 kPa, E= 4.8 ± 0.8 and 10.3 ± 1.2 kPa). This was accompanied by increased matrix metalloprotease activity (9 pmol·min–2compared to 0.6 pmol·min–2) and stress fiber formation, while cell-to-cell contacts were comparable. Likewise, release of eicosanoids (e.g., prostacyclin release of 1.7 vs 0.2 pg·mL–1·cell–1) and the pro-inflammatory cytokine MCP-1 (8 vs <1.5 pg·mL–1·cell–1) was higher on the softer than on the stiffer hydrogels. The expressions of pro-inflammatory markers COX-2, COX-1, and RAGE were slightly increased on all hydrogels on day 2 (up to 200% of the control), indicating a weak inflammation; however, the levels dropped to below the control from day 6. The study revealed that hydrogels with higher moduli approached the status of a functionally confluent HUVEC monolayer. The results indicate the promising potential especially of the discussed gelatin-based hydrogels with higher G’ as biomaterials for implants foreseen for the venous system.

Since there is growing interest throughout the world in photosynthetic microbes as a potential source of food or food supplements, an assessment of factors which influence the biomass obtained in bioreactors, protein contents and constituents is important. This work reviews the autotrophic cultivation conditions of Spirulina platensis especially the dependency on the strain, the composition of the nutrient solution, pH, temperature of the medium, light intensity and color as well as exposure rhythm, the flow rate and composition of the aerating gas mixture and the bubble size, the content of oxygen, CO2and HCO3in the medium and last but not least from the optical density of the spirulina suspension during growth.

Cell exposure to cytotoxic substrates can cause decreased cell viability or cellular death through necrosis or apoptosis. The common characteristic of both reaction patterns (necrosis and apoptosis) is a compromised or damaged cell membrane, which results in a release of the cytoplasmatic enzyme lactate dehydrogenase (LDH) into the extracellular space. For this reason the content of this enzyme in the supernatants from cells can be used as an indicator of damaged cell membrane integrity and serve as a general means to assess cell viability by measuring plasma membrane permeability. However, cell culture media which are used to maintain and to support cell growth commonly need serum supplementation, and sera already contain various LDH amounts, which may increase background absorbance in LDH release assays. Additionally the serum content varies depending on the cellular needs. For this reasons we tested the effect of different serum loads (inactivated fetal bovine serum [FBS]; 1–10 vol%) on the results of a commercially available LDH release assay (Cytotoxicity detection Kit, Roche) using 3T3 cells. An FBS concentration of 1 vol% was found to still maintain 3T3 cell viability, and after cell exposure to a cytotoxic substrate (surfactant) the cellular LDH release was higher than in the cells which were grown with higher serum concentrations (5 and 10 vol%). These results show that a serum content of 1 vol% is advantageous for cytotoxicity assays based on the LDH release, but due to the cellular differences in the need of serum components test results are limited to 3T3 cells.

Mesenchymal stem cells (MSCs) have become one of the most important cell sources for regenerative medicine. However, some mechanisms of MSC-based therapy are still not fully understood. The clinical outcome may be restricted by some MSC-related obstacles such as the low survival rate, differentiation into undesired lineages and malignant transformation. In recent years, with the emergence of nanotechnology, various types of multifunctional nanoparticles (NPs) have been designed, prepared and explored for bio-related applications. There is high potential of NPs in biomedical applications, attributed to the high capacity of cellular internalization in MSCs and their multiple functionalities. They can be used either as labeling agent to track MSCs for mechanism study or as gene/drug delivery carriers to regulate the cellular behavior and functions of MSCs. However, the application of NPs may be accompanied by some undesirable effects, as some NPs can induce cell death, inhibit cell proliferation or influence the differentiation of MSCs. Aiming to provide a comprehensive understanding of the interaction between NPs and MSCs, recent progress in the design and preparation of multifunctional NPs is summarized in this review, mechanisms of cellular internalization of the NPs are discussed, the main applications of multifunctional NPs in MSCs are highlighted and overview about cellular response of MSCs to different NPs is given. Future studies aiming on design and development of NPs with multifunctionality may open a new field of applying nanotechnology in stem cell-based therapy.

Supplemental Digital Content is available in the text.

Within the hemocompatibility testing portfolio of medical devices a range of dynamic models were established in recent years. In contrast to the static hemocompatibility testing method the dynamic models allow considering the impact of hemorheological and hemodynamic blood characteristics on the hemocompatibility of medical devices. Unfortunately the EN DIN ISO 10993-4 for the biological evaluation of medical devices for interaction with blood gives no hints towards the period of time during which the medical devices should be exposed to the blood in these tests. To examine whether different exposure times impact the comparability of hemocompatibility test results low density polyethylene (LD-PE) tubes and nitinol stents were tested exemplarily in a closed loop model for changes of the fibrinogen content, the prothrombin time, the thrombin time, and the C5a activity after 30 and 90 min exposure to the blood. Low density polyethylene was used as negative control because it is one of the European reference materials for hemocompatibility testing. After 90 min blood exposure to the LD-PE tubing and the nitinol stents the prothrombin time was significantly longer and the fibrinogen content significantly lower (p < 0.05) than after 30 min. In contrast the thrombin time and the C5a were comparable after 30 and 90 min blood exposure time. These results might recommend to an initial 30 min exposure time, which is followed by a 90 min exposure time in cases of unclear results.

Objective Most of the detected thrombi in patients with atrial fibrillation (AF) can be found in the left atrial appendage (LAA). Interventional LAA closure recently proved to be noninferior to warfarin therapy. Whether these results can be fully translated into surgical LAA closure remains unclear. Corresponding data are still lacking. The present observational study evaluated the impact of surgical LAA closure in patients with AF undergoing cardiac surgery on postoperative thromboembolic events.Methods A prospective registry enrolled 398 patients with permanent AF undergoing cardiac surgery. Concomitant procedures were isolated surgical ablation (group I, n = 71), isolated LAA closure (group II, n = 44), and combined surgical ablation and LAA closure (group III, n = 196). The control group consisted of 87 patients without concomitant surgical ablation or LAA closure. One-year follow-up was completed in all patients. End points were thromboembolic events and death from any cause.Results Clinical baseline characteristics were comparable among the groups. General hospital mortality was 5.5% and likewise differed not significantly. Postoperatively, mean (SD) CHAD2S2-VASc score of 3.5 (1.3) differed not significantly among the groups, indicating comparable thromboembolic risk. Follow-up referred to all hospital survivors (n = 376). Herein, overall incidence of thromboembolic events was 9.8% (n = 37), with an associated mortality of 41.0%. Patients with LAA closure alone or in combination with surgical ablation had a significantly reduced incidence of thromboembolic events (6.6% vs 20.5%, P < 0.01) and consecutively improved survival after 1 year of follow-up (7.0% vs 17.1%, P < 0.01).Conclusions Left atrial appendage closure alone or in combination with surgical ablation was associated with a significantly reduced rate of thromboembolic events and consecutively improved survival after 1 year of follow-up.

Objective Most of the detected thrombi in patients with atrial fibrillation (AF) can be found in the left atrial appendage (LAA). Interventional LAA closure recently proved to be noninferior to warfarin therapy. Whether these results can be fully translated into surgical LAA closure remains unclear. Corresponding data are still lacking. The present observational study evaluated the impact of surgical LAA closure in patients with AF undergoing cardiac surgery on postoperative thromboembolic events.Methods A prospective registry enrolled 398 patients with permanent AF undergoing cardiac surgery. Concomitant procedures were isolated surgical ablation (group I, n = 71), isolated LAA closure (group II, n = 44), and combined surgical ablation and LAA closure (group III, n = 196). The control group consisted of 87 patients without concomitant surgical ablation or LAA closure. One-year follow-up was completed in all patients. End points were thromboembolic events and death from any cause.Results Clinical baseline characteristics were comparable among the groups. General hospital mortality was 5.5% and likewise differed not significantly. Postoperatively, mean (SD) CHAD2S2-VASc score of 3.5 (1.3) differed not significantly among the groups, indicating comparable thromboembolic risk. Follow-up referred to all hospital survivors (n = 376). Herein, overall incidence of thromboembolic events was 9.8% (n = 37), with an associated mortality of 41.0%. Patients with LAA closure alone or in combination with surgical ablation had a significantly reduced incidence of thromboembolic events (6.6% vs 20.5%, P < 0.01) and consecutively improved survival after 1 year of follow-up (7.0% vs 17.1%, P < 0.01).Conclusions Left atrial appendage closure alone or in combination with surgical ablation was associated with a significantly reduced rate of thromboembolic events and consecutively improved survival after 1 year of follow-up.

Degradable polymers are essential to enable biomaterial‐based regenerative therapies, particularly, in articular cartilage defect healing, which remains a major clinical challenge. The aim of this study was to investigate the effect of two degradable polymers (as a film or scaffold) on primary articular chondrocytes vitality, adherence, differentiated phenotype and morphology. Films and electro‐spun scaffolds were prepared from degradable poly(ether)ester urethane (PDC), which was synthesized via co‐condensation of poly(p‐dioxanone)diol and poly(ε‐caprolactone)diol with an aliphatic diisocyanate and poly(p‐dioxanone) (PPDO). The thermal and mechanical properties and the surface roughness of the films and scaffolds were examined by differential scanning calorimetry, dynamic mechanical thermal analysis, tensile tests and optical profilometry. Primary porcine articular chondrocytes were seeded on the polymers and analysed for viability, ultrastructure (scanning electron microscopy) and immunolabelled for type II collagen. All films and scaffolds exhibited a low endotoxin load < 0.06 EU/ml and only moderate cytotoxic effects when tested with L929 cells. The results of the seeding experiments revealed that survival and adhesion of chondrocytes depended strongly on seeding density. Vital chondrocytes could be detected on both PPDO and PDC films and scaffolds. They produced the cartilage‐specific protein type II collagen indicating differentiated functions. However, they exhibited a mixed morphology on the films and a more flattened cell shape on the scaffolds. The cell/biomaterial interaction in the PPDO scaffolds or films was more intense compared to that in PDC topologies.

Biomaterial‐induced autoregeneration requires materials with distinct tailored mechanical and thermal properties, water uptake and swelling properties as well as degradation behavior. Furthermore, before any biomaterial can be applied in vivo, in vitrostudies should be performed that confirm the suitability for such applications. One facet in this process is the evaluation of endotoxin loads and immunogenic response to the material to avoid an unspecific activation of the immune system, which otherwise might cause fever and could lead to life–threatening pathologies. In this study, gelatins functionalized with desaminotyrosine (DAT) or desaminotyrosyl tyrosine (DATT) were investigated in terms of their endotoxin content and their potential to induce an inflammatory cytokine response in macrophages. Using the Limulus amebocyte lysate (LAL) test it could be shown that the endotoxin content was substantially reduced by using certified low endotoxin containing gelatin and performing the gelatin functionalization under cleanroom conditions. Furthermore, production of inflammatory cytokines such as interleukin 6 (IL‐6) and tumor necrosis factor–alpha (TNFα) of an immune relevant macrophage cell line was significantly reduced for these materials. The survival of the macrophage cell line in the presence of DAT(T)‐functionalized gelatins was not influenced by both materials. Therefore, DAT‐ and DATT‐functionalized gelatins were shown to have passed the tests concerning immunological responses important for their applicability in vivo.

Hintergrund: Die Anzahl der chirurgischen koronaren Revaskularisationsoperationen stagniert und ist in den letzten Jahren sogar leicht rückläufig. Die Frage ist, ob die Einführung von Drug-eluting Stents das Operationsspektrum der Koronarchirurgie beeinflusst. Koronarchirurgie: Die Koronarchirurgie ist ein etabliertes Verfahren zur Behandlung der koronaren Herzerkrankung mit guten Ergebnissen. Studien belegen auch einen Vorteil zugunsten der Chirurgie im Verhältnis zur interventionellen kardiologischen Therapie. Drug-eluting Stents: Die jetzt zur Verfügung stehenden Stents neuester Generation, Drug-eluting Stents, zeigen in ersten Studien eine signifikant günstigere Offenheitsrate als herkömmliche Stents. Zurzeit gibt es aber keine Studien, die auch einen Vorteil gegenüber der chirurgischen Therapie bei gleicher Indikation erbringen. Schlussfolgerung: Es ist daher zum jetzigen Zeitpunkt nicht eindeutig zu beantworten, inwieweit das Spektrum der Koronarchirurgie durch Drug-eluting Stents beeinflusst wird.

Aims:The aim of the study was to test the feasibility of the new Realtime Position Management mapping system for ablation of typical atrial flutter. Methods and Results:The ultrasound multi-transducer catheters of the RPM Mapping System are placed in the coronary sinus and at the right ventricular apex. Position and movement of the ablation catheter can be depicted on the monitor at any time. Several guiding marks are set in the right atria and thus, define the subsequent lesion lines. A total of 15 patients were treated. In 13 patients complete bi-directional block was established after the ablation. In two patients only significant conduction delay was measured after the end of the procedure. A total of 10.2 ± 6.3 cooled RF-applications were needed to reach the end-point of the procedure. The total energy was 18.76 ± 13.23 J. The fluoroscopy time for ablation was 22.2 ± 8.34 min. During a mean follow-up of 8.4 ± 3.2 months no recurrence of atrial flutter occurred. One patient developed atypical flutter and another patient had atrial fibrillation. Both patients were treated with antiarrhythmic drugs. There was one ablation related complication, a pericardial effusion. Conclusion:The Realtime Position Management system is easy to manage and control. The precision of anatomical linear lesions is improved and fluoroscopic exposure time considerably reduced after learning curve.

Abstract: • Purpose: The study was carried out to ascertain the role of blood viscosity in patients with branch retinal vein occlusion (BR-VO) with and without risk factors. • Methods: In 292 patients with acute BRVO (mean age 65 10 years) and 292 controls matched for gender, age, and cardiovascular risk factors, haematocrit, plasma viscosity, erythrocyte aggregation and erythrocyte rigidity were measured. A subgroup analysis in patients with and without risk factors was performed. • Results: Haematocrit and plasma viscosity values were significantly higher in BRVO patients than in controls, but erythrocyte rigidity and erythrocyte aggregaton did not differ. Subgroup analysis revealed no differences in haematocrit and plasma viscosity values between patients with and those without cardioavascular risk factors. • Conclusions: This study shows increased plasma viscosity and haematocrit values in patients with BRVO which are not associated with the presence of other cardiovascular risk factors. Thus, changes in blood fluidity appear to be important factors in the pathogenesis of BRVO.

Purpose:To assess the rheologic findings in acute central retinal vein occlusion (CRVO) with respect to associated risk factors, the clinical appearance of ischemic or nonischemic CRVO, and to elucidate the etiology of possible changes.

A total of 209 diabetic children and adolescents aged 6–17 years (mean, 12.6 ± 2.3 years) were examined by ophthalmoscopy, video fluorescein angiography and hemoglobin (HbA1c) tests. Microaneurysms were found in 26% of the children (ophthalmoscopy, 11%; angiography, 23%). The prevalence of retinopathy was 16% in patients aged 6–10 years, 27% in those aged 11–13 years and 36% in those aged 14–17 years. Only five diabetics aged 11–17 years showed lesions other than microaneurysms (hard exudates, intraretinal hemorrhages or retinal capillar leakage). Retinal blood flow was quantified using video fluorescein angiography. The arm-retina time (ART) and the arteriovenous passage time (AVP) as parameters of the retinal microcirculation were obtained using an image analysing system. The mean value for ART was 9.7±2.5 s and that for AVP was 1.43±0.52 s. AVP was significantly shorter in diabetic children and adolescents with good glycemic control (HbAlc, <7%; AVP, 1.35±0.44 s) than in those with bad glycemic control (HbA1c, = 9 % ; AVP, 1.65 ±0.51 s).

The short‐ and long‐term thrombogenicity of implant materials is still unpredictable, which is a significant challenge for the treatment of cardiovascular diseases. A knowledge‐based approach for implementing biofunctions in materials requires a detailed understanding of the medical device in the biological system. In particular, the interplay between material and blood components/cells as well as standardized and commonly acknowledged in vitro test methods allowing a reproducible categorization of the material thrombogenicity requires further attention. Here, the status of in vitro thrombogenicity testing methods for biomaterials is reviewed, particularly taking in view the preparation of test materials and references, the selection and characterization of donors and blood samples, the prerequisites for reproducible approaches and applied test systems. Recent joint approaches in finding common standards for a reproducible testing are summarized and perspectives for a more disease oriented in vitro thrombogenicity testing are discussed. In vitro thrombogenicity testing of biomaterials is reviewed regarding prerequisites for a reproducible in vitro testing, applied test systems, and test parameters for the characterization of the blood–material interaction. Recent approaches that may support realizing reliable, reproducible, and laboratory independent tests are outlined.

Chemical weapons manufactured today are weapons of mass destruction.