[Innovative laser technologies in the treatment of urolithiasis : A change to more gentle methods with increased patient safety]. / Innovative Lasertechnologien in der Harnsteintherapie : Ein Wandel zu schonenderen Methoden mit hoher Patientensicherheit.

Management of urolithiasis has undergone fundamental changes with the introduction of extracorporeal shock wave lithotripsy (ESWL) and percutaneous and ureterorenoscopic techniques in the 1980s. Since then, these minimally invasive techniques have been continuously optimized and specific laser techniques for stone disintegration have emerged. Besides the established holmium laser, other types of lasers are also emerging. Especially the thulium fiber laser is the subject of promising research due to its variable adjustment options. In terms of patient safety, both holmium and thulium techniques seem to be similar . While serious direct physical lesions are rare, there is increasing evidence of clinically relevant secondary thermal injury due to increased temperatures in the upper urinary tract during treatment. Our research group has recently demonstrated in both in vitro and in vivo (porcine animal model) experiments that monitoring the fluorescence spectra of calculi allows precise target differentiation between stone, tissue, and endoscope components. Consequently, pulse emissions were only emitted when stone material was detected. We believe that target monitoring will minimize the risk of laser-induced urothelial damage and decrease energy release into the upper urinary tract allowing adequate temperature management.

Colloid, adhesive and release properties of nanoparticular ternary complexes between cationic and anionic polysaccharides and basic proteins like bone morphogenetic protein BMP-2.

Herein we describe an interfacial local drug delivery system for bone morphogenetic protein 2 (BMP-2) based on coatings of polyelectrolyte complex (PEC) nanoparticles (NP). The application horizon is the functionalization of bone substituting materials (BSM) used for the therapy of systemic bone diseases. Nanoparticular ternary complexes of cationic and anionic polysaccharides and BMP-2 or two further model proteins, respectively, were prepared in dependence of the molar mixing ratio, pH value and of the cationic polysaccharide. As further proteins chymotrypsin (CHY) and papain (PAP) were selected, which served as model proteins for BMP-2 due to similar isoelectric points and molecular weights. As charged polysaccharides ethylenediamine modified cellulose (EDAC) and trimethylammonium modified cellulose (PQ10) were combined with cellulose sulphatesulfate (CS). Mixing diluted cationic and anionic polysaccharide and protein solutions according to a slight either anionic or cationic excess charge colloidal ternary dispersions formed, which were cast onto germanium model substrates by water evaporation. Dynamic light scattering (DLS) demonstrated, that these dispersions were colloidally stable for at least one week. Fourier Transform Infrared (FTIR) showed, that the cast protein loaded PEC NP coatings were irreversibly adhesive at the model substrate in contact to HEPES buffer and solely CHY, PAP and BMP-2 were released within long-term time scale. Advantageously, out of the three proteins BMP-2 showed the smallest initial burst and the slowest release kinetics and around 25% of the initial BMP-2 content were released within 14days. Released BMP-2 showed significant activity in the myoblast cells indicating the ability to regulate the formation of new bone. Therefore, BMP-2 loaded PEC NP are suggested as novel promising tool for the functionalization of BSM used for the therapy of systemic bone diseases.

Rapid protyping technology in medicine--basics and applications.

Using medical models built with Rapid Prototyping (RP) technologies represents a new approach for surgical planning and simulation. These techniques allow one to reproduce anatomical objects as 3D physical models, which give the surgeon a realistic impression of complex structures before a surgical intervention. The shift from the visual to the visual-tactile representation of anatomical objects introduces a new kind of interaction called 'touch to comprehend'. As can be seen, from the presented case studies of maxillo-cranio-facial surgery, the RP models are very well suited for use in the diagnosis and the precise preoperative simulation of skeleton modifying interventions.

Seeding of human vascular cells onto small diameter polyurethane vascular grafts.

INTRODUCTION: Thrombogenicity of small diameter vascular prostheses might be reduced by complete coverage of the luminal surface with vascular cells. We investigated cell seeding on polyurethane vascular prostheses (PUVP). METHODS: 45 PUVP were divided into three groups of n = 15 each: Group A (diameter 20 mm, gamma-sterilized), Group B (diameter 4 mm, gamma-sterilized), and Group C (diameter 4 mm, ethylene oxid [Eto]-sterilized). Human smooth muscle cells (SMC), fibroblasts (FB), and endothelial cells (EC) were isolated from saphenous vein segments and expanded in culture. PUVPs were pre-seeded with a mixed culture of FBs and SMCs (mean 7.7 +/- 2.3 x 10(6) cells) followed by EC seeding (mean 4.4 +/- 0.9 x 10(6) cells). Seven days after cell seeding, PUVPs were perfused under a pulsatile flow. Flow definitions were as follows: adaption phase: low flow, resulting pressure: 60/30 mm Hg; high flow: resulting pressure: 160/50 mm Hg, lasting for 4 hours in all groups. Three subgroups were defined out of each group, differing in the perfusion strategy: high flow immediately, adaption phase of 15 minutes followed by high flow, and adaption phase of 30 minutes followed by high flow. Specimens were taken after each seeding procedure, prior to and after perfusion, and then examined using a scanning electron microscope (SEM) and immunohistochemical staining procedures. RESULTS: Pre-seeding with the mixed culture revealed a better initial adhesion in Groups A and B compared to group C (76% vs. 41%). In Groups A and B, EC seeding (adhesion 72%) resulted in a confluent EC layer. Immunohistochemical stainings were positive for collagen IV, laminin, CD31, and factor VIII, but negative for eNOS. In Group C, only isolated cells were found after each seeding procedure, which rounded up and vanished during the next days. When perfused with high-flow immediately, Group A and B prostheses revealed small defects (< 10% of the surface) of all cell layers. After perfusion with an adaption phase of 15 minutes only few defects were found within the EC layer with an intact basement membrane. An adaption phase of 30 minutes resulted in a confluent cell layer without significant cell defects. After perfusion, the endothelial cells also stained positive for eNOS. CONCLUSION: Seeding of a mixed culture consisting of FBs and SMC resulted in an excellent EC adhesion and resistance to shear stress. Cell attachment was better on gamma-sterilized PUVPs compared to Eto-sterilization. The cells obviously maintained their ability to adapt to shear stress.

A low-flow adaptation phase improves shear-stress resistance of artificially seeded endothelial cells.

INTRODUCTION: The purpose of this study was to evaluate the effect of different adaptation phases on the shear-stress resistance of endothelial cells seeded artificially onto vascular prostheses and biological heart valves. MATERIAL AND METHODS: Human endothelial cells (EC), fibroblasts (FB), and smooth muscle cells (SMC) were isolated from vena saphena magna pieces and expanded in culture. Group A: 15 polyurethane vascular grafts (20 mm diameter) were seeded with FB and SMC (53 +/- 1.2 million cells), followed by EC seeding (39 +/- 0.9 million cells). Group B: eight stentless porcine valves (Freestyle, Medtronic, USA) were seeded with FB (68 +/- 1.5 million cells) and EC (42 +/- 1.1 million cells). Shear-stress testing was done under pulsatile flow (pulse rate: 80 pulses/min.). Adaptation phase: flow was set to 0.9 +/- 0.3 l/min (systolic pressure: 40 - 50 mm Hg). High flow was 3.2 +/- 0.6 l/min. (systolic pressure: 140 - 160 mm Hg) and lasted over four hours in all groups. The vascular grafts were divided into three groups (n = 5 each): group 1 (high flow immediately), group 2 (adaptation phase of 15 minutes), and group 3 (adaptation phase of 30 minutes). The valves either were given high flow immediately (n = 4) or had an adaptation phase of 30 minutes (n = 4). Specimens were obtained after cell seeding, before, and after perfusion. RESULTS: A confluent EC layer was achieved on all grafts. After perfusion without adaptation, large defects within the cell layer were found. No FB and SMC were seen at the bottom of these defects. In group B, the defects were largest on the ventricular surface of the leaflets. After an adaptation phase of 15 minutes in group A, only a few defects within the EC layer were detected with a still confluent FB and SMC. After a 30-minute adaptation phase defects within the EC layer were very rare and no interruption of the underlying FB and SMC layer was seen. Immunohistochemical staining for factor VIII and CD31 proved the EC to be viable and staining for collagen IV and laminin revealed the formation of a basement membrane. After perfusion, the specimen also stained positive for eNOS. CONCLUSION: An adaptation phase of 30 minutes proved to be sufficient to allow artificially seeded endothelial cells to adapt to shear stress. The formation of a basement membrane was of great importance for the maintenance of a confluent EC layer.

[Possibilities for the detection and monitoring of children and adolescents with hypertension]. / Möglichkeiten der Erfassung und Betreuung von Kindern und Jugendlichen mit Blutdruckerhöhung.

Blood pressure measurements have been taken for ten years or more on the basis of a standard programme as part of the paediatric mass screening, starting with the second medical examination for school entrance. They have now become an integral component of this checkup routine. The following recommendations are made for a revised prophylactic examination programme: enlargement of case history questionnaire on arterial hypertension, maintenance of present valid norms and recommendations for medical attention in cases of high blood pressure risk, and blood pressure measurements for school entrants in grades 6 and 9.

Enhanced immunogenicity in mice of a purified, tween-ether-treated influenza vaccine.

The immunogenic response of mice vaccinated intranasally or subcutaneously with increasing doses of a purified, concentrated intact A(2)/Taiwan influenza vaccine or its Tween-ether derived vaccines was compared. Immunogenicity was measured by serum neutralization and hemagglutination-inhibition antibodies, lung lesions scores, and protection against respiratory challenge with live airborne influenza virus. Intact (untreated) vaccine, Tween-ether-treated (ET) vaccine, and the isolated hemagglutinins (HA) provided protection and stimulated homologous antibody response at the 35- and 70-chicken cell agglutination (CCA) unit level. At a lower dosage level, the vaccines administered by the subcutaneous route appeared to confer better protection. The ET vaccine was superior to intact virus or HA vaccines when administered subcutaneously. The minimum amount of the HA and intact vaccine given subcutaneously that protected mice against respiratory challenge was 7 CCA units (3.5 units injected twice) compared to 0.7 CCA units (0.35 units injected twice) for the ET vaccine. No heterologous antibody to the A/PR/8/34 or B/Mass/3/66 was noted. Low-level serum-neutralizing antibody was found against the A(2)/Japan/170 strain but, despite high levels of homologous A(2)/Taiwan/64 antibody, no cross-reactivity was found with the recent A(2)/Hong Kong/68 variant.