High-energy phosphate metabolism in the exercising muscle of patients with peripheral arterial disease

Patients with peripheral arterial disease (PAD) suffer from impaired muscle function due to insufficient oxygen supply during exercise, mitochondrial damages, unfavourable muscle fibre type distribution and impaired exercise tolerance. These factors influence the symptoms as well as the quality of life in PAD patients and are closely connected to failures of high-energy phosphate metabolism. At onset of muscle exercise, the mitochondrial capacity cannot match the increased demand. The oxygen supply via blood flow must be increased. Meanwhile, anaerobic glycolysis and internal stores of oxygen like mixed venous blood and myoglobin as well as internal stores of high-energy phosphates like phosphocreatine (PCr) are adducted for the provision of additional adenosine-triphosphate (ATP), which is consumed by the ATPase at the myofibrils in order to fuel muscle contraction. Since the ATP production is insufficient, this phase (anaerobic phase) is characterized by a progressive decrease in PCr, which can be accurately measured by phosphorus 31 magnetic resonance spectroscopy (31p MRS). If the oxygen supply is improved, the mitochondrial capacity can match the increased metabolic demand. This phase is the aerobic phase, which is indicated by a steady-state of PCr hydrolysis. In PAD patients or experimental models of peripheral ischemia, the anaerobic phase is prolonged or does not pass into the aerobic phase resulting in exercise abortion. This review summarizes the results of 31p MRS studies investigating the high-energy phosphate metabolism during ischemic exercise in healthy humans and during ramp or incremental exercise in PAD patients.

[Merkel cell carcinoma--clinically often misjudged]

Merkel cell carcinoma is a rare, rapidly growing, highly malignant dermal tumor which occurs preferentially on light-exposed skin in advanced age. The course of the disease is frequently characterized by the occurrence of lymph node metastases and local recurrences, even in the first year after removal of the primary tumour. The five-year overall survival rate is only about 65 %, despite rigorous therapy. The histological pattern is characterized by trabecular strands of small, uniform cells with large basophilic nuclei and typical neuroendocrine granules. The diagnosis is confirmed immunohistochemically by neuroendocrine and epithelial markers. The excision of the primary tumor is regarded as first-line therapy. Adjuvant radiatiotherapy is almost always indicated and should also include lymph node drainage. In the stage of nodal disease, a combination of excision and radiotherapy is recommended. Adjuvant chemotherapy can be applied in this stage, as in small-cell bronchial carcinoma. The prognostic advantage has, however, not been proven. Despite good response to radiatiotherapy and chemotherapy, with at least prolonged recurrence-free intervals, Merkel cell carcinoma is rarely curable at the distant metastasizing stage. Individually defined, aggressive treatment,including radiatiotherapy, may in future considerably improve the prognosis, especially in the early stages of the disease.

One-step production of polymeric microtubes by co-electrospinning

Herein we demonstrate the ability to fabricate polymeric microtubes with an inner diameter of approximately 3 microm through co-electrospinning of core and shell polymeric solutions. The mechanism by which the core/shell structure is transformed into hollow fibers (microtubes) is primarily based on the evaporation of the core solution through the shell and is described here in detail. Additionally, we present the filling of these microtubes, thus demonstrating their possible use in microfluidics. We also report the incorporation of a protein (green fluorescent protein) within such fibers, which is of interest for sensorics.

Poly(ethylene carbonate): A thermoelastic and biodegradable biomaterial for drug eluting stent coatings?

A first feasibility study exploring the utility of poly(ethylene carbonate) (PEC) as coating material for drug eluting stents under in vitro conditions is reported. PEC (Mw 242 kDa, Mw/Mn=1.90) was found to be an amorphous polymer with thermoelastic properties. Tensile testing revealed a stress to strain failure of more than 600%. These properties are thought to be advantageous for expanding coated stents. In vitro cytotoxicity tests showed excellent cytocompatibility of PEC. Based on these findings, a new stenting concept was suggested, pre-coating a bare-metal stent with PPX-N as non-biodegradable basis and applying a secondary PEC coating using an airbrush method. After manual expansion, no delamination or destruction of the coating could be observed using scanning electron microscopy. The surface degradation-controlled release mechanism of PEC may provide the basis for "on demand" drug eluting stent coatings, releasing an incorporated drug predominantly at an inflamed implantation site upon direct contact with superoxide-releasing macrophages. As a release model, metal plates of a defined size and area were coated under the same conditions as the stents with PEC containing radiolabelled paclitaxel. An alkaline KO(2-) solution served as a superoxide source. Within 12 h, 100% of the incorporated paclitaxel was released, while only 20% of the drug was released in non-superoxide releasing control buffer within 3 weeks.

[Heat shock protein 90 alpha und beta are overexpressed in multiple myeloma cells and critically contribute to survival]

HSP90's are overexpressed in different cancer types and they probably are required to sustain aberrant signalling in malignant cells. Recently, pharmacological inhibition of HSP90 was found to suppress growth of myeloma cell lines and in primary myeloma cells. Therefore, we wanted to investigate the role of HSP90alpha and HSP90beta in the pathogenesis of malignant myeloma (MM) in more detail. Immunohistochemistry was employed to examine the expression of HSP90alpha and HSP90beta in MM. The importance of HSP90 for survival of MM -cells was investigated by SiRNA-mediated knockdown of HSP90 and blockade of the IL-6R/STAT3 and the MAPK signaling pathways in vitro. HSP90alpha and HSP90beta were overexpressed in majority of investigated MM cases, but not in MGUS or in normal plasma cells. SiRNA-mediated knockdown of HSP90 or treatment with the novel HSP90 inhibitor 17-DMAG attenuated the levels of STAT3 and phospho-ERK and decreased the viability of MM cells. The knockdown of HSP90alpha was sufficient to induce apoptosis. This effect was strongly increased when both HSP90s were targeted, indicating a cooperation of both. HSP90 critically contributes to myeloma survival in the context of its microenvironment and therefore strengthen the potential value of HSP90 as a therapeutic target.

Technical and clinical success of infrarenal endovascular abdominal aortic aneurysm repair: A 10-year single-center experience

OBJECTIVE

The aim of our retrospective study was to review our single-center experience with aortic abdominal aneurysm (AAA) repair retrospectively.

MATERIAL AND METHODS

From 1995 to 2005, 70 consecutive patients affected by AAA were treated by endovascular stent-graft repair. Mean follow-up was 23.9 months. Follow-up investigations were performed at 6 and 12 months and yearly thereafter. Five different stent-graft designs were compared to each other. Primary technical success (PTS), assisted primary technical success (APTS), primary clinical success (PCS) and secondary clinical success (SCS) were evaluated.

RESULTS

All over PTS was achieved in 94.3%, APTS in 97.1%, PCS in 61.4%, APCS in 64.3% and SCS in 70%. There were 3 type I endoleaks, 25 type II endoleaks, 4 type III endoleaks, 8 limb problems, 5 conversions to open surgery, 10 aneurysm sac expansions and 14 device migrations. Patients with newer generation devices showed better results than patients with first generation prosthesis. In addition results were better for grafts with suprarenal fixation (versus infrarenal fixation) and grafts with barbs and hooks (versus grafts without barbs and hooks). Patients with bad anatomic preconditions showed a higher complication rate.

CONCLUSION

Contrary to first generation products, new stent-graft designs show acceptable technical and clinical results in endovascular AAA aneurysm repair. However, this therapy still should be reserved only for patients with significant comorbities and suitable anatomic conditions.

Biohybrid nanosystems with polymer nanofibers and nanotubes

Advanced techniques for the preparation of nanofibers, core shell fibers, hollow fibers, and rods and tubes from natural and synthetic polymers with diameters down to a few nanometers have recently been established. These techniques, among them electro- and co-electrospinning and specific template methods, allow the incorporation not only of semiconductor or catalytic nanoparticles or chromophores but also enzymes, proteins, microorganism, etc., directly during the preparation process into these nanostructures in a very gentle way. One particular advantage is that biological objects such as, for instance, proteins can be immobilized in a fluid environment within these polymer-based nano-objects in such a way that they keep their native conformation and the corresponding functions. The range of applications of such biohybrid nanosystems is extremely broad, for instance, in the areas of biosensorics, catalysis, drug delivery, or optoelectronics.

Mid-term Results after Endovascular Repair of the Atherosclerotic Descending Thoracic Aortic Aneurysm

INTRODUCTION

Thoracic aortic aneurysms (TAA) are the most common condition of the thoracic aorta requiring surgical treatment. Despite significant improvement in anesthetic, surgical techniques and postoperative care, the mortality and morbidity rate in TAA-repair remains high. The aim of this study was to assess the morbidity and mortality rate after endovascular stent-graft treatment of atherosclerotic (non-dissecting) TAAs.

METHODS

Thirty-one patients, ASA-classification III-IV, with symptomatic or expanding atherosclerotic TAAs underwent endovascular stent-graft repair between May 1997 and August 2003. Procedures were performed on an emergency basis in 13 patients and elective in 18 patients. Patients were assessed postoperatively by routine CT-scan within 48 h. Further follow up investigations were performed after 3, 6, 12 months and annually thereafter.

RESULTS

Stent-graft placement was successful in all but one patient in whom the stent-graft procedure had to be postponed due severe hemodynamic instability. Perioperative mortality rate was 19% including three haemorrhages, two cardiac events and one respiratory failure (6/31). Technical success rate was 55% (17/31). Completion CT scans performed in 30 patients within 2 days of stent-graft procedure showed type I leaks in seven patients (23%), type II leaks in four patients (13%) and type III leaks in two patients (6%). Further complications included one stroke, one paralysis, one spinalis anterior syndrome and five relevant access related complications. New onset endoleaks, all type I, were observed in seven patients (23%) occurring after 3, 4, 7, 8, 17, 25 and 26 months. Mean follow-up was 15 months (range 2-69 months).

CONCLUSION

Thoracic aortic atherosclerotic aneurysm stent-grafting is feasible but not without significant morbidity and mortality.

Alexithymia is no risk factor for exacerbation in spasmodic torticollis patients

OBJECTIVE

To assess whether alexithymia is a risk factor for exacerbation in spasmodic torticollis (ST).

METHODS

ST patients (2 x 10) with high vs. low alexithymia scores (mean score on the 20-item Toronto Alexithymia Scale [TAS-20]=69.2 vs. 28.7) were compared on physiological, motor and subjective responses to a cognitive and an emotional laboratory stressor. Changes in sustained abnormal head/shoulder positions and maximum range of motion (ROM) of the cervical spine were kinematically quantified. Skin conductance level (SCL), nonspecific skin conductance fluctuations (NS.SCF), heart rate (HR) and skin temperature (T) were measured.

RESULTS

High alexithymia had no effect on the abnormal head posture or movements, but high-alexithymic ST patients showed generally increased levels of autonomic arousal (more NS.SCF, higher SCL; analysis of variance [ANOVA]: P=.016 and P=.051, respectively) under all experimental conditions. When ST symptom severity (TSUI-score) was partialled out, these group differences were somewhat reduced (analysis of covariance [ANCOVA]: P=.052 and P=.143).

CONCLUSIONS

High alexithymia did not lead to increased abnormal head movements to stressors, but may result in a subtle increase in tonic level of sympathetic activity.

Neuropathic pain after femoropopliteal bypass surgery

OBJECTIVE

This retrospective study was performed to investigate prolonged postoperative pain in the area of the proximal or distal scar or the bypass tunnel after femoropopliteal bypass surgery to treat symptomatic peripheral arterial disease.

PATIENTS AND METHODS

Ninety-three patients with peripheral arterial disease who underwent femoropopliteal bypass surgery between January 2000 and December 2002 were included in the study. The short-form McGill Pain Questionnaire was used to score pain. Ultrasound examination of the soft tissue around the graft was performed to exclude other pathologic conditions responsible for pain, such as inflammatory processes, perigraft reactions, swollen lymph nodes, and hematomas.

RESULTS

Pain in at least one scar existed in 22 patients on average 13.9 +/- 9.8 months after surgery. In 10 patients pain existed simultaneously along the inguinal scar and the above-knee or below-knee scar. Pain along the bypass tunnel was experienced by seven patients. Most patients had mild to moderate pain. The mean numeric ranking score of pain severity in patients with pain was 4.2 +/- 2.3. The occurrence of prolonged postoperative pain was not associated with age, gender, diabetes, indication for surgery, material or type of bypass, number of preceding operations, or postoperative wound complications. Only follow-up time after femoropopliteal bypass surgery tended to be lower in patients with pain compared with those without pain.

CONCLUSION

Prolonged postoperative neuropathic pain along the distal and proximal incision or the bypass tunnel exists in one fourth of patients after femoropopliteal bypass surgery. Patients should be informed of this kind of complication before surgery. The results of our study justify further investigations of the origin and treatment of this pain, to find effective methods to reduce the incidence of prolonged postoperative pain after femoropopliteal bypass surgery.

Receptor revision of immunoglobulin heavy chain genes in human MALT lymphomas

BACKGROUND/AIMS

Rearrangement of immunoglobulin gene segments, leading to B cells with functional receptors, is thought to be largely restricted to developing immature B cells in bone marrow. However, accumulating evidence suggests that mature B cells occasionally modify their antigen specificity by VH segment replacements during the germinal centre reaction to enhance antigen affinity, or to overcome self reactive antigen receptors. Although malignant B cells maintain the features of their normal counterparts in most instances, to date, such replacements have not been described for human B cell lymphomas.

METHODS

Rearranged immunoglobulin heavy chain genes from two extranodal marginal zone B cell lymphomas were amplified, cloned, and sequenced. Sequences with identical CDR3 regions were selected and aligned to each other and public databases.

RESULTS

VH replacements were seen in two extranodal marginal zone B cell lymphomas. In line with the hypothesis that in mature B cells these replacements are associated with active somatic hypermutation, in addition to VH replacement, different mutation patterns were seen in the revised VH portions. In the remaining common 3'-VH regions, these mutations could be used to establish a phylogenetic relation between the sequences, rendering the possibility of artefactual chimaeric polymerase chain reaction products very unlikely.

CONCLUSIONS

These results support the view that VH replacements are a further mechanism for reshaping antigen affinity and specificity, and indicate that these receptor modifications are not restricted to normal and reactive germinal centre B cells, but may also occur in close association with the development of malignant B cell lymphomas.

Long term outcome of patients with gastric marginal zone B cell lymphoma of mucosa associated lymphoid tissue (MALT) following exclusive Helicobacter pylori eradication therapy: experience from a large prospective series

BACKGROUND

Helicobacter pylori plays a decisive role in the pathogenesis of gastric marginal zone B cell lymphoma of mucosa associated lymphoid tissue (MALT), and eradication therapy has become a widely accepted initial treatment of stage I disease.

OBJECTIVE

To determine the long term outcome of patients undergoing exclusive H pylori eradication therapy.

DESIGN

A prospective series of patients with newly diagnosed marginal zone B cell lymphoma of MALT.

SETTING

Multicentre study in Germany and Austria.

PATIENTS

Ninety five patients; 90 of these (five lost to follow up) with a mean age of 54.3 (27-85) years were followed up for at least 12 months.

INTERVENTION

Complete staging work up revealing stage I disease and H pylori infection. Patients received triple therapy (OMC: omeprazole 20 mg twice daily, metronidazole 400 mg twice daily, and clarithromycin 250 mg twice daily; or OAC: omeprazole 20 mg twice daily, amoxycillin 1000 mg twice daily, and clarithromycin 500 twice daily) for one week.

RESULTS

Median follow up was 44.6 (12-89) months. H pylori was successfully eradicated in 88 patients (98%); in two patients eradication therapy failed. Long term outcome was characterised by complete regression of lymphoma in 56 patients (62%), minimal residual disease in 17 patients (18%), partial remission in 11 patients (12%), no change in four patients (4%), and progressive disease in two patients (2%). Four patients with complete remission relapsed after 6, 8, 8, and 15 months, one revealing reinfection by H pylori. Regression rate was higher in stage I1 disease compared with stage I2, as diagnosed by endoscopic ultrasound.

CONCLUSION

The majority of patients with low grade gastric MALT lymphoma treated by exclusive H pylori eradication have a favourable long term outcome, offering a real chance of cure.

Elektrogesponnene Poly-L- Laktid-Nanofasern als resorbierbare Matrix für Tissue-Engineering / Electrospun Poly-l-lactide Nanofibres as Scaffolds for Tissue Engineering

Tissue engineering is a promising tool for treating structural and functional defects in bone and cartilage. To provide optimal conditions for three-dimensional cell growth the use of a scaffold is necessary. The aim of the study was to test the potential application of an electrospun poly (l-lactide)-nanostructured scaffold as a matrix for tissue engineering. Matrices were seeded with human osteosarcoma MG-63 cells and cultivated for 14 days. Cells showed a clear preference for growth along the nanofibres, and demonstrated no signs of degeneration or apoptosis. The fine structure of electrospun nanofibres makes them an ideal scaffold for tissue engineering, in particular for cartilage repair. They can be "doped" with growth factors, medications, etc., and are both biocompatible and biodegradable.