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Biomedical subjects

U Frank

Publications and source records attributed to U Frank.

At least 19 recordsLinked to original sources

Activities of various beta-lactams and beta-lactam/beta-lactamase inhibitor combinations against Acinetobacter baumannii and Acinetobacter DNA group 3 strains.

Acinetobacter baumannii and Acinetobacter DNA group 3 are members of the so-called A. calcoaceticus-A. baumannii complex and are important nosocomial pathogens. Multiresistance in these organisms is increasingly frequent, and alternative treatment options are needed. The beta-lactamase inhibitors clavulanate, sulbactam and tazobactam have intrinsic activity against Acinetobacter strains. In the present study, broth microdilution was used to assess the in-vitro activities of currently available beta-lactam/beta-lactamase inhibitor combinations and sulbactam alone against 469 Acinetobacter isolates (A. baumannii, n=395; Acinetobacter DNA group 3, n=74) collected from various laboratories in Germany. Fixed concentrations and fixed ratios of beta-lactamase inhibitors were used. Sulbactam-containing combinations (susceptibility rates of 90.4-92.7% for A. baumannii and 97.3-100% for Acinetobacter DNA group 3) and sulbactam alone were superior to clavulanate- and tazobactam-containing combinations. The activity of sulbactam-containing combinations against members of the A. calcoaceticus-A. baumannii complex was conferred exclusively by the intrinsic activity of the beta-lactamase inhibitor and did not result from enhanced beta-lactam activity. Testing with the inhibitor added at a fixed ratio of inhibitor to beta-lactam appeared to give more reliable results than testing at a fixed concentration of the inhibitor. Resistance to carbapenems (0.3%) remains low in Germany.

Acinetobacter↗

Effects of caspofungin (MK-0991) and anidulafungin (LY303366) on phagocytosis, oxidative burst and killing of Candida albicans by human phagocytes.

The objective of the present study was to investigate the influence of the new echinocandins caspofungin (MK-0991) and anidulafungin (LY303366) on human phagocytes. Phagocytosis, oxidative burst and intracellular killing of Candida albicans were analyzed by flow cytometry. Neither caspofungin nor anidulafungin significantly influenced phagocytosis. Only caspofungin significantly influenced oxidative burst after 15 min of incubation ( P<0.05). Both caspofungin and anidulafungin improved intracellular killing rates of C. albicans after 2 h of incubation (42.4% and 43.2%, respectively, compared to 37.9% in controls; P<0.05). In conclusion, caspofungin significantly improves oxidative burst and intracellular killing, which may be advantageous for clinical therapy.

Anidulafungin↗

Histological verification of non-specific aorta-arteritis (Takayasu's arteritis) using percutaneous transluminal atherectomy.

Diagnosis of non-specific aorto-arteritis (NSAA, Takaysu's arteritis) is typically based on clinical and investigational parameters. We report here about two patients with clinically suspected diagnosis of a Takayasu's arteritis already under anti-inflammatory therapy in whom percutaneous transluminal atherectomy of subclavian and axillary artery stenoses was performed to relief the patients from symptoms--intermittent dyspraxia of the arms--and to verify the clinical diagnosis by histology. In the first case aorto-arteritis could be histologically confirmed through the analysis of plaque material including media structures excised from the subclavian and axillary arteries using a new device for atherectomy. The biopsy showed diffuse inflammation and granulomatous lesions with giant cells typically for Takayasu's disease. In the second patient, biopsy showed no acute or chronic inflammatory signs but only atherosclerotic lesions. Percutaneous transluminal atherectomy is therefore not only an interventional but also a diagnostic tool and should be used in every case of interventional therapy of suspected aorto-arteritis to make the clinical diagnosis and as a major consequence the initiation of an aggressive anti-inflammatory medical therapy more reliable.

Adult↗

[Initial clinical experience with a new percutaneous peripheral atherectomy device for the treatment of femoro-popliteal stenoses].

BACKGROUND: Evaluation of the efficacy and safety of a new 7F-atherectomy device (30-day endpoint) for the treatment of short and mid-length arterial lesions with a reference diameter of 2.5-7 mm. MATERIAL AND METHODS: Fifty-eight femoto-popliteal stenoses in 46 patients (67% male, mean age 66 +/- 9 years) with chronic peripheral occlusive disease of the lower limbs [Rutherford stage 2: n = 13 (28%); stage 3: n = 29 (63%), stage 4: 2 (4%), stage 5: n = 2 (4%)], were treated with directional atherectomy. Target lesion characteristics: Common femoral artery: n = 1 (2%), superficial femoral artery: n = 47 (81%); popliteal artery, n = 10 (17%); in stent n = 3 (5 %). Thirty (65 %) of the interventions were performed using an antegrade approach, 16 (35%) interventions in cross-over technique. Mean degree of stenosis was 83 +/- 11 mm, mean length of lesion was 37 +/- 37 mm. RESULTS: 6.5 +/- 2 (4-10) passes of the lesion were performed with the catheter. Three lesions were treated after predilatation, 55 (95%) interventions as primary atherectomy. In 31/58 lesions (53%) additional balloon angioplasty was performed, in 1 lesion (2%) additional stent placement was needed. The mean degree of stenosis after atherectomy was reduced to 29 +/- 20% (0-60%) after additional balloon angioplasty, it was 11 +/- 10% (0-30 %). A residual stenosis of < 50% after plain atherectomy was achieved in 55 (95%) lesions, of < 30% in 49 (84%). COMPLICATIONS: 3 (6.5%) cases of embolism of debris were detected and treated successfully by aspiration. The mean ankle-brachial index increased from 0.62 +/- 0.12 to 0.92 +/- 0.36 before discharge, and to 0.86 +/- 0.17 after 30 days. Rutherford stage after 30 days: stage 0: n = 038 (83%); Stage 1: n = 4 (8%); Stage 2: n = 3 (6%); Stage 5: n = 1 (2%). CONCLUSION: Lesions up to 8 cm in length of the femoropopliteal arteries can be treated successfully in most cases with the new atherectomy catheter. Embolism, the only complication that occurred, can be avoided by cleaning the nose cone after at least 4 passes of the lesion.

Aged↗

Influence of mistletoe ( Viscum album) extracts on phagocytosis/burst activity of human phagocytes.

The aim of the present study was to examine the in vitro effects of various mistletoe extracts on human phagocytes. Phagocytosis, oxidative burst, and intracellular killing were analyzed by flow cytometry. None of the mistletoe preparations investigated exhibited significant phagocytosis-enhancing properties. Different mistletoe lectin concentrations ranging from 0.025 to 20 ng/ml showed only marginal influence on phagocyte activity. Contrary to the opinion of numerous practitioners of complementary medicine, the mistletoe preparations tested do not enhance phagocytic function.

Candida albicans↗

Treatment of acute embolic occlusions of the subclavian and axillary arteries using a rotational thrombectomy device.

Acute embolic or local thrombotic ischaemia of the upper limbs can be treated by embolectomy or by endovascular techniques. We report here on the endovascular thrombectomy of acute embolic occlusions of subclavian and axillary arteries in two patients using a rotational thrombectomy device and give an overview about the actual literature. Two female patients, each with a history of multivessel coronary disease and intermittent atrial fibrillation, complained of sudden onset of pain at rest and paleness of the left and right arm, respectively. Duplex ultrasound showed a localized embolic occlusion of the left subclavian artery and the bifurcation of the brachial artery in the first patient and a localized embolic occlusion of the distal right subclavian and axillary artery in the second patient. In the first patient, the left subclavian artery was reopened using a 8F-Rotarex device via the femoral access, while the bifurcation of the brachial artery was reopened by local thrombolysis using 25 mg rt-PA because of the insufficient length of the thrombectomy device of 80 cm. In the second patient, the right subclavian and axillary arteries were reopened using a 6F-Rotarex device. Follow-up examinations before discharge and after 6 months showed normalized perfusion of the arms of both patients.

Acute Disease↗

Surveillance of nosocomial infections in adult recipients of allogeneic and autologous bone marrow and peripheral blood stem-cell transplantation.

To identify overall and site-specific rates of nosocomial infections (NIs) during the neutropenic, as compared to the non-neutropenic stage of treatment in adult recipients of allogeneic and autologous bone marrow transplantation (BMT) and peripheral blood stem-cell transplantation (PBSCT), a prospective, 54-month study was started at the Haematological Stem Cell Transplantation Unit of the University Hospital of Freiburg, Germany. NI types were identified using modified CDC definitions. A total of 351 patients (14 256 in-patient days, 5026 neutropenic days) were investigated (316/90% allogeneic, 35/10% autologous; BMT: 119 patients, PBSCT: 234 patients). The mean length of neutropenia was 14.3 days (range: 0-66). Antimicrobial prophylaxis for allogeneic transplantation consisted of ciprofloxacin, trimethoprim/sulpha-methoxazole, fluconazole, and metronidazole. In total, 239 NIs were identified in 169 patients (48.1%), and of these 171 (71.5%) occurred during neutropenia (34.0 NIs per 1000 days at risk). The main pathogens were coagulase-negative staphylococci (36.3%), Clostridium difficile (20.4%), and enterococci (10.0%). Site-specific incidence densities during neutropenia vs non-neutropenia were: 13.9 vs 1.6 bloodstream infections (all central line-associated), 11.9 vs 1.8 pneumonias, 3.0 vs 2.9 gastroenteritis, and 1.6 vs 0.3 urinary tract infections. The greatest number of NI in BMT and PBSCT recipients is acquired during neutropenia, and multicentre surveillance programmes should focus on this.

Adult↗

Comparative in vitro activity of piperacillin, piperacillin-sulbactam and piperacillin-tazobactam against nosocomial pathogens isolated from intensive care patients.

We investigated the antimicrobial activity of piperacillin-tazobactam versus piperacillin-sulbactam against common nosocomial pathogens (n = 565) isolated from intensive care patients. For Gram-positive bacteria, antimicrobial susceptibilities to the two piperacillin-beta-lactamase inhibitor combinations were almost identical. For Gram-negative bacteria, piperacillin-tazobactam exhibited greater activity against Escherichia coli and Proteus vulgaris than piperacillin-sulbactam. Both combinations, however, were equally effective against the other Enterobacteriaceae and Pseudomonas aeruginosa isolates. Piperacillin-sulbactam exhibited better antimicrobial activity against Acinetobacter baumannii. Our findings might prove important for the appropriate choice of antibiotic therapy with beta-lactam-beta-lactamase inhibitor combinations.

Anti-Bacterial Agents↗

Effect of skin disinfection with octenidine dihydrochloride on insertion site colonization of intravascular catheters.

BACKGROUND: We investigated the efficacy of two commercially available, alcohol-based antiseptic solutions in decontaminating the insertion site of central lines. One solution contained the bispyridine octenidine dihydrochloride. PATIENTS AND METHODS: Inpatients receiving either a central venous catheter (CVC) or a peripherally inserted central catheter (PICC) were alternately assigned to different skin disinfection regimens at the insertion site: (A) 0.1% octendine dihydrochloride with 30% 1-propanol and 45% 2-propanol, (B) 74% ethanol with 10% 2-propanol. Quantitative skin cultures were obtained from the insertion site at predetermined intervals. RESULTS: A total of 60 patients received 12 CVCs and 47 PICCs (no significant difference with respect to gender, age and catheter type). In total, 90 cultures were assessed in each group. The median colony-forming unit (cfu) counts per 24 cm(2) (group A vs B) were 2,270 vs 2,950 before, 20 vs 40 following and 860 vs 1,210 24 h after catheter insertion, respectively. A statistically significant difference in the efficacy of skin decontamination was seen between groups in culture set (3) and in the difference between culture sets (2) and (3) (Wilcoxon rank sum test). CONCLUSION: Octenidine/propanol appears to be more effective than alcohol (ethanol/propanol) alone in reducing microflora of the skin at the PICC/CVC insertion site over a 24-h period.

1-Propanol↗

[First experiences with a 6F-sheath compatible self-expanding nitinol stent].

BACKGROUND: To evaluate the efficacy, safety and limitation of a new 6F-compatible nitinol stent (Dynalink(TM). MATERIAL AND METHODS: We treated 50 patients (17 women, 33 men, mean age 72 +/- 8 years) by implanting 80 Dynalink(TM)-stents into 75 vessels during a 6-month period. Target lesions were: iliac artery: 25, femoral artery: 31, popliteal artery: 16, femoro-popliteal bypass: 5, subclavian vein: 3. Preinterventional Rutherford classifications: Class 1 : 3 legs (5 %), class 2 : 27 legs (51 %), class 3 : 16 legs (31 %), class 4 : 2 legs (4 %), class 5 : 5 legs (9 %). 40 % stents each were implanted ipsilateral, 60 % cross-over. RESULTS: All interventions were successful regardless of a sometimes anatomically difficult access to the lesion. The device was characterised by a high flexibility and radial force and the stent did not shorten. COMPLICATIONS: One distal stent dislocation during placement occurred, no puncture site complication. The mean diameter stenosis was reduced from 91 +/- 10 % (75 - 100 %) to 4 +/- 8 % (0 - 30 %). The ankle-brachial index was improved from 0.46 +/- 0.22 to 0.75 +/- 0.23 (p < 0.001). Post-interventional Rutherford classifications: Class 0 : 43 legs (81 %), class 1 : 5 legs (4,5 %), class 5 : 5 legs (4,5 %). CONCLUSIONS: The new 6F-sheath compatible nitinol stent is characterised by a good flexibility, radial force, and a lack of shortening. By the reduction of the diameter of the device to 6F, the potential risk of a local bleeding complication may be reduced and 6F sealing devices will be usable. Disadvantages are the 0.018 inch guide-wire lumen and the limited stent sizes.

Adult↗

[Normal values for the internal thoracic artery by Doppler ultrasound and modification of the Doppler curve after bypass to the left anterior descending artery].

AIM: In coronary heart disease, the surgical therapy of choice is the construction of an artenal bypass of the left anterior descending artery (LAD) using the internal thoracic artery 8ITA). We define age dependent normal values for the ITA such as diameter of the lumen (LD), peak systolic (Vs) and diastolic (Vd) flow velocity and the ratio of these two values (SDR) measured by duplex ultrasound. Furthermore, the modification and pathological changes of the Doppler curve after minimal invasive bypass of the LAD (MIDCAB) are described. MATERIAL AND METHODS: 96 people, age 18 - 87 years, subdivided into 6 age groups were examined by duplex to define the normal values of the ITA, and 55 patients (mean age 63 +/- 10 years, 48 men, 7 women) were evaluated after MIDCAB-surgery to describe the postoperative modification of the Doppler curve. The examinations were performed using a 4 - 7 MHz linear ultrasound transducer in the right and left 1. or 2. intercostal space parasternally. RESULTS: In all 96 people, the ITA was detectable on both sides presenting a typical bi- or triphasic Doppler flow profile. A linear age dependent increase in the LD of 1.95 +/- 0.15 mm (right ITA) and 1.93 +/- 0.27 mm (left ITA) respectively to 2.65 +/- 0.48 mm and 2.55 +/- 0.43 mm was found. No significant side difference was found for Vs and Vd, nor were there any age dependent differences for Vs. The SDR showed an age dependent linear increase on the right side from 3.5 +/- 1.1 to 6.1 +/- 2.2, p < 0.0012, and on the left from 3.9 +/- 1.2 to 6.7 +/- 1.7, p < 0.0001. Postoperatively, the Doppler spectrum was modified into a mono- or biphasic Doppler curve with a reduced Vs and an increased Vd resulting in a significantly decreased SDR on the left side compared with the right side (1.3 +/- 0.8 vs. 5.4 +/- 2.0, p < 0.00001). Three patients with angiographically proven graft failure had an SDR of 2.6 - 5.2 (mean 3.8), as opposed to a value of < 2.0 in case of a patent bypass. An SDR > 2.0 has a sensitivity of 100 % and a specificity of 97 % in the detection of a haemodynamically relevant (>70 %) ITA-graft-stenosis. CONCLUSIONS: With rising age, there is an increase in the LD of the ITA and the peripheral resistance, expressed as SDR. After MIDCAB surgery the former triphasic Doppler flow curve changes into a mono- or biphasic curve corresponding to the coronary blood flow. An SDR >2.0 is a strong indicator of bypass failure.

Adolescent↗

[Duplex ultrasound for follow-up examination after stent-angioplasty of ostial renal artery stenoses].

AIM: Renal artery stenosis (RAS) may lead to deterioration of renal function and/or hypertension. Stent angioplasty has become the method of choice in the treatment of atherosclerotic ostial RAS. We describe the changes of the following duplex parameters: intrarenal resistance index RI according to Pourcelot and the renal-aortic flow velocity ratio (RAR) directly after intervention and during follow-up (FU). We also examine the value of the method in detecting restenosis. PATIENTS AND METHODS: We present the results of a prospective study of 241 patients with stent angioplasty for the treatment of 355 severe RAS (extent of stenosis >/= 70 % of vessel diameter). Duplex examinations during FU were performed before discharge, after 6 and 12 months, and then annually resulting in 1292 examinations. RESULTS: RAR could be calculated in 98.9 % (1278/1292), RI was calculated in 100 % of the examinations. The RAR decreased significantly from 5.9 +/- 2.1 to 1.2 +/- 0.4 after intervention (p < 0.00001) with a slight increase during follow-up. RI increased significantly from 0.64 +/- 0.11 to 0.74 +/- 0.06 after intervention (p < 0.00001), equalling the RI of the contralateral side (0.74 +/- 0.07). During a mean FU of 27 +/- 15 months, 37 restenosis (10.4 %) and 12 re-restenosis were detected and confirmed angiographically, resulting in 48 reinterventions. In case of restenosis, RAR increased from 1.3 +/- 0.4 to 6.3 +/- 2.8 (p < 0.001) with a decrease to 1.3 +/- 0.6 after reintervention (p < 0.001), and RI decreased from 0.75 +/- 0.08 to 0.64 +/- 0.11 (p < 0.001) with an increase to 0.75 +/- 0.07 after reintervention (p < 0.001). CONCLUSIONS: Duplex ultrasound is a reliable method for FU of patients after renal artery stent-angioplasty and for detecting restenosis.

Adult↗

[Long-term results after recanalization of acute and subacute thrombotic occlusions of the infra-aortic arteries and bypass-grafts using a rotational thrombectomy device].

BACKGROUND: Evaluation of the acute and long-term results after recanalization of thrombotic occlusions of infra-aortic native arteries, stented arteries and bypass-grafts using a rotational thrombectomy device (8F Straub-Rotarex TM). MATERIALS AND METHODS: From July 2000 to February 2002, in 98 patients (64 % male, mean age 66 +/- 9 (range 47 to 90) years, mean duration of occlusion 31 +/- 33 (range 0 to 140) days, mean occlusion length 21 +/- 11 [range 2 to 40] cm) 100 vessel recanalizations were performed. 42 % of the interventions were performed during the first 14 days after the onset of the symptoms (acute occlusions). These patients were classified according to the after the TASC protocol modified SVS/ISCVS-classification: Class I: n = 22 (52 %); class lla: n = 13 (32 %); class llb: n = 6 (14 %); class III: n = 1 (2 %). Subacute and chronic occlusions were classified according to Rutherford (58 %): Stage 1: n = 5 (9 %); stage 2 and 3: n = 39 (68 %); stage 4: n = 6 (10 %); stage 5: n = 8 (13 %). RESULTS: Primary success rate was 96 % (ipsilateral interventions 99 %, cross-over 40 %). The restenosis rate after a mean follow-up of 13 +/- 4 months was 33 % for native arteries (group 1), 74 % for instent-recanalizations (group 2) and 86 % for bypass-graft occlusions (group 3). 3 % severe complications occurred: two amputations below the knee after unsuccessful recanalizations of a native artery and a bypass-graft, respectively. One death because of multiorgan failure in patient who was already in cardiac shock before the successful intervention. Further 16 complications could be solved periinterventionally. The ancle-brachial index was significantly improved during follow-up (from 0.37 +/- 0.19 to 0.82 +/- 0.22 before discharge, 0.70 +/- 0.21 after 12 months, p < 0.001). CONCLUSION: The Straub-Rotarex TM device is useful in the treatment of acute and subacute thrombotic occlusions of infra-aortic arterial and bypass-graft occlusions, with promising long-term results in native vessels but unchanged high restenosis of stented arteries and bypass-grafts.

Acute Disease↗

Alloimmune memory is absent in the Red Sea hydrocoral Millepora dichotoma.

When two allogeneic colonies of the Red Sea hydrocoral Millepora dichotoma (Cnidaria, Hydrozoa) come into tissue contact, one of the genotypes is usually overgrown by the other. The directionality and pace of this alloresponse are thought to be genetically determined. We established tissue contacts between allogeneic colonies in situ in order to elucidate a possible memory component in this response. First-set interactions were established from all possible pairwise combinations between three colonies in eight replicates per combination. Interactions were followed up for 8 weeks. Thereafter, interacting pairs were detached and either regrafted near the original contact area to form second-set assays or challenged by third party grafts. Additional delayed first-set assays was also established. Overgrowth of delayed first-set, second-set, and third-party grafts was followed again for 8 weeks. The mean overgrowths recorded in the second set of the interactions were indistinguishable from the first sets in all three colony combinations. A specific alloimmune memory has not been found in this cnidarian system as opposed to other cases within the phylum.

Animals↗

The hydroid Hydractinia: a versatile, informative cnidarian representative.

The Cnidaria represent the most ancient eumetazoan phylum. Members of this group possess typical animal cells and tissues such as sensory cells, nerve cells, muscle cells and epithelia. Due to their unique phylogenetic position, cnidarians have traditionally been used as a reference group in various comparative studies. We propose the colonial marine hydroid, Hydractinia, as a convenient, versatile platform for basic and applied research in developmental biology, reproduction, immunology, environmental studies and more. In addition to being a typical cnidarian representative, Hydractinia offers many practical and theoretical advantages: studies that are feasible in Hydra like regeneration, pattern regulation, and cell renewal from stem cells, can be supplemented by genetic analyses and classical embryology in Hydractinia. Metamorphosis of the planula larva of Hydractinia can be used as a model for cell activation and communication and the presence of a genetically controlled allorecognition system makes it a suitable model for comparative immunology. Most importantly, Hydractinia may be manipulated at most aspects of its (short) life cycle. It has already been the subject of many studies in various disciplines, some of which are discussed in this essay.

Animals↗