Dynamic angioplasty--a milling catheter for transcutaneous and intraoperative treatment of vascular occlusive disease

Balloon angioplasty and bypass graft surgery are common procedures for treating vascular occlusive disease. The purpose of this preliminary investigation was to evaluate the effectiveness and the safety of a new catheter system, first introduced by KR Kensey. The system involves a flexible catheter with a high speed rotating tip, driven by an electrical motor. The tip is cooled by a continuous flow of sterile saline containing dextran 40, heparin and urokinase. Radiopaque contrast medium may be infused through the catheter to allow the device to be guided and to detect lesions and to evaluate the efficacy of treatment. The system was applied in three patients with occlusive vascular disease (Stage IIb) and segmental or total occlusion of the superficial femoral artery (SFA). The milling catheter was introduced percutaneously into the common femoral artery and guided to the area of occlusion under DSA control. In two patients total recanalisation was achieved after passage of the milling catheter. In one patient the totally occluded SFA could not be cannulated and a femoro-popliteal bypass was performed one week later. Complications such as perforation of the vessel or peripheral embolisation were not observed. Pedal pulses were improved significantly in one patient. Further investigations will be necessary to demonstrate whether the milling catheter can be safely used to revascularise patients with limb threatening peripheral vascular disease.     

Aktuelle Daten und Trends zur β-Lactam-Resistenz bei gramnegativen Infektionserregern

In recent years the resistance of Gram-negative pathogens to beta-lactam antibiotics, such as cephalosporins and carbapenems has increased. The resistant strains produce different beta-lactam hydrolysing enzymes (beta-lactamases). In particular extended spectrum beta-lactamases (ESBL) are prevalent in Escherichia coli and Klebsiella pneumoniae. The ESBL genes are located on different plasmids facilitating the transfer of resistance within a species and between different Gram-negative species. Within the scope of various studies the Robert Koch Institute in Wernigerode investigated ESBL-producing human Enterobacteriaceae using molecular methods. The results showed that distinct ESBL types, such as the CTX-M enzymes are dominant in Germany whereby CTX-M-15 and CTX-M-1 are the most prevalent variants in E. coli and K. pneumoniae. The aim of ongoing investigations within the RESET network project is to investigate the dissemination pathways of ESBL-producing bacteria in different settings (e.g. in humans, animals and food).     

Viral gene transfer for xenotransplantation

In order to overcome the major immunological barriers to xenotransplantation, genetic strategies have to be developed that ensure long‐term engraftment of the organ. To this end, immune‐modulatory transgenes have to be efficiently expressed and/or the expression of xeno‐relevant porcine genes (xeno‐epitopes) has to be silenced. Viral vectors are powerful tools for modulating expression of foreign genes in organs and even the whole animal. Using lentiviral gene transfer in early embryos, gain‐of‐function models can be generated with high efficacies in pig (lentiviral transgenesis). Through combination of lentiviral transgenesis and RNA interference (RNAi) loss‐of‐function models for xenotransplantation can be generated. Our goal is to combine lentivector‐mediated RNAi directed against α‐galactosyltransferase (α‐GT) with immune‐modulatory approaches to finally generate multitransgenic pigs. Furthermore, sensitivity to human serum inactivation of porcine endogenous retrovirus produced by pig cells with reduced levels of α‐GT expression was analysed.     

Physiological assessment of the polytrauma patient: initial and secondary surgeries

The timing of fracture fixation in polytrauma patients has been debated for a long time. The decision between DCO (damage control orthopaedics) and ETC (early total care) is a difficult dilemma. Overzealous ETC in haemodynamically compromised patients with significant chest and head injuries can be detrimental. It has been shown, however, that early fracture fixation has a trend towards better outcome in patients with less severe injuries. Delaying all orthopaedic surgery in critically injured patients can be a safe alternative, but has several disadvantages like longer ICU stay and septic complications. The literature shows equivocal evidence for both settings. This article will summarize the historical background and controversies regarding patient assessment and decision making during the treatment of polytrauma patients. It will also give guidance for choosing DCO versus ETC in the clinical setting.     

Multiple macroregenerative nodules in liver cirrhosis due to Budd-Chiari syndrome. Case reports and review of the literature

Clinical, radiological, histological and immunohistochemical methods were used to define the nature of multiple rapidly growing hepatic nodules in 2 young patients with Budd-Chiari syndrome due to myeloproliferative diseases. In one patient, the arterial hyperperfusion of large nodules was demonstrated by dynamic computed tomography and angiography. The explanted livers of these patients showed multiple well-demarcated nodules up to 3 cm in diameter on the background of liver cirrhosis resulting from chronic hepatic congestion. Histologically, these nodules covered a spectrum ranging from adenoma-like lesions to nodules resembling focal nodular hyperplasia. They consisted of essentially normal hepatocytes, and variably contained fibrous septa including neoductules and large, mostly dysmorphic arteries. Sometimes, they were located close to still patent or recanalized veins. These rapidly growing hepatic nodules are best defined as macroregenerative nodules. The knowledge of this entity may help the physician to avoid misinterpretation of such nodules as carcinomas.     

Intramyocardial blood volume,perfusion and transit time in response to embolization of different sized microvessels

OBJECTIVE: To study the role of the coronary microcirculation in response to different-sized microemboli, we measured changes in intramyocardial microvascular blood volume (Bv), perfusion (F) and transit time (TT) and also microvascular patterns of injury. METHODS: Bv, F and TT were quantitated in 24 pigs at baseline and again 2 min after repeat injections of 10- or 100-microm microspheres at rest or during intracoronary adenosine infusion. The association of Bv and TT was assessed in the microsphere pigs and in nine control pigs. Microvascular injury was studied on gross-pathologic and histologic samples. RESULTS: At rest, initial injection of 10-microm microspheres led to increases in Bv and F, but progressively decreased with additional injections. In contrast, even small numbers of 100-microm microspheres always led to decreases in Bv and F. Injection of microspheres during adenosine-induced vasodilation always resulted in decreases in peak Bv and F irrespective of their diameters, but microvascular TTs remained unaltered. In control pigs, however, TTs were inversely related to adenosine-induced changes in Bv. Histologically, 100-microm microspheres resulted in patchy distribution of microcirculatory plugging, while 10-microm microspheres induced contiguous hemorrhagic myocardial injury. CONCLUSION: Microsphere-induced changes in intramyocardial Bv and F and the associated pattern of myocardial injury are related to the size of embolized microvessels and the initial perfusion state. Microvascular functional volume reserve mechanisms appear to play a key role accompanying flow- and TT-preservation.