Host cell protein networks as a novel co-elution mechanism during protein A chromatography

Host cell proteins (HCPs) are process-related impurities of therapeutic proteins produced in for example, Chinese hamster ovary (CHO) cells. Protein A affinity chromatography is the initial capture step to purify monoclonal antibodies or Fc-based proteins and is most effective for HCP removal. Previously proposed mechanisms that contribute to co-purification of HCPs with the therapeutic protein are either HCP-drug association or leaching from chromatin heteroaggregates. In this study, we analyzed protein A eluates of 23 Fc-based proteins by LC-MS/MS to determine their HCP content. The analysis revealed a high degree of heterogeneity in the number of HCPs identified in the different protein A eluates. Among all identified HCPs, the majority co-eluted with less than three Fc-based proteins indicating a drug-specific co-purification for most HCPs. Only ten HCPs co-purified with over 50% of the 23 Fc-based proteins. A correlation analysis of HCPs identified across multiple protein A eluates revealed their co-elution as HCP groups. Functional annotation and protein interaction analysis confirmed that some HCP groups are associated with protein-protein interaction networks. Here, we propose an additional mechanism for HCP co-elution involving protein-protein interactions within functional networks. Our findings may help to guide cell line development and to refine downstream purification strategies.

Therapy aspects of peri-implant femoral fractures-a retrospective analysis of 64 patients

PURPOSE

The incidence of peri-implant femoral fractures (PIFF) is increasing. Information regarding outcomes, timing of surgery, risk factors, and a clinically applicable treatment algorithm are lacking. The aim of this study was to identify outcome-related risk factors and to derive a treatment algorithm.

METHODS

Sixty-four PIFFs treated between 01.01.2006 and 31.12.2020 in a level I trauma centre were evaluated retrospectively for fracture pattern, surgical technique, risk factors, complications, and 1-year mortality. The study was approved by the ethics committee (No. 21-2714-104).

RESULTS

One-year mortality was 24.1%. Surgical complications occurred in 4.7%, and general complications in 15.6% of the patients. General complications, low haemoglobin level at admission, elevated CHA2DS2-VASc, and Charlson score resulted in increased 1-year mortality. Time to surgery > 24 h did not increase complication or mortality rates. The three predominant fracture patterns were fractures close or distal to cephalomedullary nails, close or proximal to distal lateral plates, and close or distal to sliding hip screws. Recommendations for surgical treatment were derived: Osteosynthesis should enable as much weight-bearing as possible; the initial implant should only be removed, if this is essential for the new osteosynthesis; lateral locking plates should span the whole femur; antegrade nails should have a cephalomedullary component to avoid consecutive femoral neck fractures; implants should overlap to reduce the risk of consecutive inter-implant fractures.

CONCLUSION

Risk factors for 1-year mortality in patients with PIFFs were identified. A treatment algorithm and general principles for surgery of PIFFs were developed.

Surgery Within 24 Hours Reduces Mortality and General Complication Rates in Patients Who Have Periprosthetic Femoral Fractures at the Hip

BACKGROUND

In patients who have hip fractures, treatment within 24 hours reduces mortality and complication rates. A similar relationship can be assumed for patients who have hip periprosthetic femoral fractures (PPFs) owing to the similar baseline characteristics of the patient populations. This monocentric retrospective study aimed to compare the complication and mortality rates in patients who had hip PPF treated within and after 24 hours.

METHODS

In total, 350 consecutive patients who had hip PPF in a maximum-care arthroplasty and trauma center between 2006 and 2020 were retrospectively evaluated. The cases were divided into 2 groups using a time to surgery (TTS) of 24 hours as the cutoff value. The primary outcome variables were operative and general complications as well as mortalities within 1 year.

RESULTS

Overall, the mean TTS was 1.4 days, and the 1-year mortality was 14.6%. The TTS ≤ 24 hours (n = 166) and TTS > 24 hours (n = 184) groups were comparable in terms of baseline characteristics and comorbidities. Surgical complications were equally frequent in the 2 groups (16.3 versus 15.2%, P = .883). General complications occurred significantly more often in the late patient care group (11.4 versus 28.3%, P < .001). In addition, the 30-day mortality (0.6 versus 5.5%, P = .012), and 1-year mortality (8.3 versus 20.5%, P = .003) rates significantly increased in patients who had TTS > 24 hours. Cox regression analysis yielded a hazard ratio of 4.385 (P < .001) for the TTS > 24 hours group.

CONCLUSIONS

Prompt treatment is required for patients who have hip PPF to reduce mortality and overall complications.

Effectiveness of wearable devices as a support strategy for maintaining physical activity after a structured exercise intervention for employees with metabolic syndrome: a randomized controlled trial

Background

Metabolic syndrome (MetS) is associated with an increased risk for cardiovascular events and high socioeconomic costs. Despite lifestyle interventions focusing on exercise are effective strategies to improve parameters of the above aspects, many programs fail to show sustained effects in the long-term.

Methods

At visit 2 (V2) 129 company employees with diagnosed MetS, who previously participated in a 6-month telemonitoring-supported exercise intervention, were randomized into three subgroups for a 6-month maintenance treatment phase. A wearable activity device was provided to subgroup A and B to assess and to track physical activity. Further subgroup A attended personal consultations with individual instructions for exercise activities. Subgroup C received neither technical nor personal support. 6 months later at visit (V3), changes in exercise capacity, MetS severity, work ability, health-related quality of life and anxiety and depression were compared between the subgroups with an analysis of variance with repeated measurements.

Results

The total physical activity (in MET*h/week) declined between visit 2 and visit 3 (subgroup A: V2: 48.0 ± 33.6, V3: 37.1 ± 23.0; subgroup B: V2: 52.6 ± 35.7, V3: 43.8 ± 40.7, subgroup C: V2: 51.5 ± 29.7, V3: 36.9 ± 22.8, for all p = 0.00) with no between-subgroup differences over time (p = 0.68). In all three subgroups the initial improvements in relative exercise capacity and MetS severity were maintained. Work ability declined significantly in subgroup C (V2: 40.3 ± 5.0, V3: 39.1 ± 5.7; p < 0.05), but remained stable in the other subgroups with no between-subgroup differences over time (p = 0.38). Health-related quality of life and anxiety and depression severity also showed no significant differences over time.

Conclusions

Despite the maintenance of physical activity could not be achieved, most of the health related outcomes remained stable and above baseline value, with no difference regarding the support strategy during the maintenance treatment phase.

Trial registration The study was completed as a cooperation project between the Volkswagen AG and the Hannover Medical School (ClinicalTrials.gov Identifier: NCT02029131).

COMPARISON OF WEARABLES FOR SELF-MONITORING OF HEART RATE IN CORONARY REHABILITATION PATIENTS

The leading cause of morbidity and mortality in the world is ischemic heart disease. Physical activity is a major approach in prevention and therapy of cardiac diseases. Self-heart-rate-monitoring in daily life is an important point for health awareness of cardiac patients. Aim of this study was validation of measurement accuracy of seven different devices against ECG-monitoring during cardiac rehabilitation training on a bicycle ergometer. Tested devices were: Garmin Forerunner 35 (Garmin), Mio Fuse (Mio), Fitbit Charge HR (FitbitHR), Fitbit Surge (FitbitS), Withings Pulse™ Ox (Withings), Apple Watch Series 1 (Apple) and Pearl Fitness-Tracker (FBT-50.HR PRO.V4). All devices were tested on 35 participants with six timed measurements during 20 minutes constant load bicycle ergometer workout for each. Simultaneousely, ECG measurements were recorded. Pearson´s correlations were assessed. Apple, Mio, and Garmin showed excellent accuracy with close correlation to ECG for self-monitoring of heart rate (HR) during cycling. FitbitHR, Pearl and FitbitS presented reasonable results. In contrast, Withings showed poor correlation to ECG with significant differences. We found significant differences between the tested devices. Since accuracy is of major importance for cardiac patients, only Apple, Mio and Garmin could be recommended. However, further research within distinct clinical and non-clinical settings is necessary and should take different types of physical activities into account.

[Disease-related knowledge acquisition through structured patient information in rheumatoid arthritis (StruPI-RA) : First results of the StruPI-RA study in Germany]

BACKGROUND/OBJECTIVE

The structured patient information for rheumatoid arthritis (StruPi-RA) program was the first standardized outpatient education program in rheumatoid arthritis (RA) in Germany. The main objective of the study was to determine the efficacy of the StruPi-RA program concerning disease-specific knowledge acquisition in patients with early stage RA or after changing the treatment regimen.

METHODS

A total of 61 patients were included in a control group design, 32 in the intervention group (IG) and 29 in the control group (CG). Patients of the IG attended 3 modules of 90 min in a structured patient information program (StruPI-RA) including the topics of diagnostics, treatment and living with RA. Patients in the CG only received information material from the German Rheumatism League. The primary target criterion was the disease-related acquisition of knowledge, measured with the patient knowledge questionnaire (PKQ). Data were collected before and after participation in StruPI-RA.

RESULTS

The improvement in knowledge in the IG attending the StruPI-RA compared to the CG was significant in time and group comparisons. No influence of disease duration or educational level was observed. The subscale treatment alone showed a significant difference in the group and time comparison.

CONCLUSION

Participation in the StruPI-RA program in early RA was associated with a significant increase in disease-specific knowledge compared to the control group of patients. This leads to better decision-making in terms of treatment, a more beneficial doctor-patient communication and better self-management. In the long term an improvement in treatment adherence and quality of life is expected.

Highland games: A benchmarking exercise in predicting biophysical and drug properties of monoclonal antibodies from amino acid sequences

Biopharmaceutical product and process development do not yet take advantage of predictive computational modeling to nearly the degree seen in industries based on smaller molecules. To assess and advance progress in this area, spirited coopetition (mutually beneficial collaboration between competitors) was successfully used to motivate industrial scientists to develop, share, and compare data and methods which would normally have remained confidential. The first "Highland Games" competition was held in conjunction with the October 2018 Recovery of Biological Products Conference in Ashville, NC, with the goal of benchmarking and assessment of the ability to predict development-related properties of six antibodies from their amino acid sequences alone. Predictions included purification-influencing properties such as isoelectric point and protein A elution pH, and biophysical properties such as stability and viscosity at very high concentrations. Essential contributions were made by a large variety of individuals, including companies which consented to provide antibody amino acid sequences and test materials, volunteers who undertook the preparation and experimental characterization of these materials, and prediction teams who attempted to predict antibody properties from sequence alone. Best practices were identified and shared, and areas in which the community excels at making predictions were identified, as well as areas presenting opportunities for considerable improvement. Predictions of isoelectric point and protein A elution pH were especially good with all-prediction average errors of 0.2 and 1.6 pH unit, respectively, while predictions of some other properties were notably less good. This manuscript presents the events, methods, and results of the competition, and can serve as a tutorial and as a reference for in-house benchmarking by others. Organizations vary in their policies concerning disclosure of methods, but most managements were very cooperative with the Highland Games exercise, and considerable insight into common and best practices is available from the contributed methods. The accumulated data set will serve as a benchmarking tool for further development of in silico prediction tools.

Obesity After Kidney Transplantation-Results of a KTx360°Substudy

OBJECTIVE

There is solid evidence that kidney transplant (KTx) patients are susceptible to weight gain after transplantation. Post-transplantation obesity [body mass index (BMI) ≥ 30 kg/m2] seems to be associated with higher risks of hypertension, dyslipidemia, diabetes mellitus, and cardiovascular events, while there are contradicting findings regarding the association between obesity and mortality, graft failure after transplantation as well as other variables. We aimed to evaluate the course of weight after KTx and to assess the prevalence of post-transplant obesity in a large sample of German KTx patients. Further, we focused on potential associations between weight gain, obesity, and BMI after transplantation with sociodemographic, medical, psychological [levels of anxiety and depression measured with the Hospital Anxiety and Depression Scale (HADS)], and donation-specific variables.

METHODS

In a structured post-transplant care program 433 KTx patients were evaluated at Hannover Medical School. Information on the pre-transplant body weight/dry weight of dialysis patients was taken from the electronic patient charts. At post-transplant assessment body weight was measured in the transplant center. For statistical analyses, descriptive statistics, analyses of variance, tests for correlations, and regression analyses were used.

RESULTS

Mean age was 51.3 years, 59% were male and 26.3% had ≥12 years of school attendance. Regarding somatic conditions 6.0% were suffering from type 2 diabetes mellitus, 6.9% were affected by new-onset diabetes after transplantation (NODAT), and the mean estimated glomerular filtration rate (eGFR) was 47.7 ml/min/1.73m2. The prevalence rates of obesity before and after kidney transplantation were 14.8 and 19.9%, respectively. This represents an increase of 34%. Obesity after transplantation was associated with higher rates of type 2 diabetes mellitus and of NODAT. Additionally, there was an association between increasing pre-transplant as well as post-transplant BMI and decreasing eGFR. Higher age and female sex were associated with higher rates of post-transplant obesity.

CONCLUSIONS

Our results suggest that obesity represents a serious problem in KTx patients, especially regarding the association between increasing BMI and decreasing graft functioning (eGFR). However, this aspect is often overlooked and information on effective treatment options for these patients are scarce making further research on this topic necessary.

eHealth-supported case management for patients with panic disorder or depression in primary care: Study protocol for a cRCT (PREMA)

Background

Panic disorder (PD), frequently occurring with agoraphobia (AG), and depression are common mental disorders in primary care and associated with considerable individual and societal costs. Early detection and effective treatment of depression and PD/AG are of major importance. Cognitive behavioural exposure exercises have been shown to be effective in reducing anxiety and depressive symptoms. Practice team-based case management can improve clinical outcomes for patients with chronic diseases in primary care. The present study aims at evaluating the effects and cost-effectiveness of a primary care team-based intervention using behavioural therapy elements and case management supported by eHealth components in patients with PD/AG or depression compared to treatment as usual.

Methods/design

This is a two-arm cluster-randomized, controlled trial (cRCT). General practices represent the units of randomisation. General practitioners recruit adult patients with depression and PD ± AG according to the International Classification of Diseases, version 10 (ICD-10). In the intervention group, patients receive cognitive behaviour therapy-oriented psychoeducation and instructions to self-managed exposure exercises in four manual-based appointments with the general practitioner. A trained health care assistant from the practice team delivers case management and is continuously monitoring symptoms and treatment progress in ten protocol-based telephone contacts with patients. Practice teams and patients are supported by eHealth components. In the control group, patients receive usual care from general practitioners. Outcomes are measured at baseline (T0), at follow-up after 6 months (T1), and at follow-up after 12 months (T2). The primary outcome is the mental health status of patients as measured by the Mental Health Index (MHI-5). Effect sizes of 0.2 standard deviation (SD) are regarded as relevant. Assuming a drop-out rate of 20% of practices and patients each, we aim at recruiting 1844 patients in 148 primary care practices. This corresponds to 12.5 patients on average per primary care practice. Secondary outcomes include depression and anxiety-related clinical parameters and health-economic costs.

Discussion

If the intervention is more effective than treatment as usual, the three-component (cognitive behaviour therapy, case-management, eHealth) primary care-based intervention for patients suffering from PD/AG or depression could be a valuable low-threshold option that benefits patients and primary care practice teams.

Trial registration

German clinical trials register, DRKS00016622. Registered on February 22nd, 2019.

Long-term outcome after surgical treatment of intra-articular tibial plateau fractures in skiers

INTRODUCTION

Tibial plateau fractures occur frequently during downhill skiing. There is a lack of information about the outcome and development of posttraumatic osteoarthritis after internal fixation of such fractures at long-term follow-up in skiers.

MATERIALS AND METHODS

A population of 83 skiers was followed up in a case series after internal fixation of intra-articular tibial plateau fractures AO-OTA 41 B1-B3 and C1-C3. Functional outcomes Visual Analog Scale, Tegner Activity Scale, Modified Lysholm Score, Hospital for Special Surgery (HSS) Knee Score and X-ray images of the affected knees (preoperative, postoperative and at time of follow-up) were obtained. Radiological evaluation focused on severity of osteoarthritis according to the Kellgren and Lawrence score of the lateral, medial and retropatellar knee compartments separately. Subgroup analyses for fracture type and age were performed separately.

RESULTS

Patients age was 49.8 ± 12.9 years (range 19-74 years) at the time of surgery, with a mean follow-up period of 10.3 ± 1.9 years (range 6-14 years). All tibial plateau fractures affected the lateral compartment, while the medial compartment was affected in addition as part of bicondylar fractures in two cases. Both the Tegener Activity Scale and Lysholm Score decreased significantly during the follow-up period and their median values dropped from 6 (range 3-7) to 5 (range 2-7) and from 100 (range 90-100) to 95 (range 58-100), respectively (both p < .01). The median clinical knee function at the time of follow-up revealed an HSS Knee Score of 96.5 points (range 74-100). Among the whole patient population, the radiological evaluation at follow-up revealed a significantly higher grade of osteoarthritis in all compartments of the knee joint compared to the time of the operation (p < .01). The grade of osteoarthritis in the lateral compartment was significantly higher than that in the medial and retropatellar compartments (p < .01).

CONCLUSIONS

In addition to physiologic aging, progression of radiologic signs of osteoarthritis following internal fixation of intra-articular tibial plateau fractures in an athletic population of skiers is most severe in the lateral knee compartment corresponding to fracture location. However, the long-term functional outcomes seem to be very satisfactory.

The determination of the validity of an application-based knee-training device

The goals of knee rehabilitation are to improve range of motion and muscle status. The aim of the study was to investigate accuracy and reproducibility of a newly designed knee-training device (KT) under standardized laboratory conditions.Two application-based software programs, one to measure maximum force and the other intended to improve users' coordination were developed to be used on a tablet during exercises, wirelessly connected to KT placed under the popliteal fossa.KT was loaded for 20 intervals of 15 seconds (s) ranging between 0-350 Newton (N) each. The interval of times was chosen to be enough to take right measurement for accurate results. In addition, a 300-s continuous measurement was undertaken. The pressure readings were developed through a servo-hydraulic system and used as reference values. KT results were compared with the reference values to assess its accuracy. In addition, KT was tested on a force-measuring platform in a close to reality measurement.Based on Bland-Altman plots, the mean difference between KT and material testing machine was -0.63 N (0.4%), between KT and force-measuring platform was -0.11 N (0.7%), which proves the accuracy of its result.Laboratory experiments confirm that KT delivers precise and reproducible values, which provide base for clinical trials.

Long-term radiographic appearance of calcium-phosphate synthetic bone grafts after surgical treatment of tibial plateau fractures

OBJECTIVES

Synthetic bone grafts (SBGs) are widely used to fill bone defects after fracture reduction. This study assessed the long-term resorption of two different calcium phosphate products (A=ChronOS™ inject and B=Norian^® SRS^®; both DePuy Synthes, Oberdorf, Switzerland) used in the surgical treatment of tibial plateau fractures.

DESIGN

Long-term clinical and radiologic follow-up of 52 patients after surgical treatment of intraarticular tibial plateau fractures augmented with SBGs.

SETTING

The study was performed at a level 3 trauma center.

PATIENTS

Between January 2000 and December 2006 a total of 52 patients with intraarticular tibial plateau fractures were operatively treated and augmented with SBGs consisting of a Brushite matix with β-TCP granules (SBG A) or hydroxylapatite with 4-6% carbonate content (SBG B). 46 patients could be contacted and 38 were included in the study. Half of the patients received SBG A and the other half SBG B.

MAIN OUTCOME MEASUREMENTS

Loss of reduction and SBG resorption was investigated by comparison of follow-up X-ray images to pre- and postoperative X-ray images. Furthermore, pain, activity level and knee function were evaluated by means of questionnaires and clinical examination.

RESULTS

The mean age of patients was 59.7±12.5years. The follow-up was 8.6±0.9years for SBG A and 11.6±1.4years for SBG B (p<0.001). In most cases SBG A was completely resorbed in a homogenous pattern, while SBG B was still visible on the X-ray images revealing a peripheral resorption pattern. A loss of reduction (>2mm) could be observed in two patients with SBG A and two patients with SBG B, although only one of them had an impaired knee function.

CONCLUSIONS

The composite SBG A reveals a comprehensive long-term resorption in comparison to SBG B. Nevertheless, both provided suitable mechanical support as part of the surgical treatment of tibial plateau fractures.

LEVEL OF EVIDENCE

Case series, Level IV.

Fun During Knee Rehabilitation: Feasibility and Acceptability Testing of a New Android-Based Training Device

PURPOSE

The initial goals of rehabilitation after knee injuries and operations are to achieve full knee extension and to activate quadriceps muscle. In addition to regular physiotherapy, an android-based knee training device is designed to help patients achieve these goals and improve compliance in the early rehabilitation period. This knee training device combines fun in a computer game with muscular training or rehabilitation. Our aim was to test the feasibility and acceptability of this new device.

METHODS

50 volunteered subjects enrolled to test out the computer game aided device. The first game was the high-striker game, which recorded maximum knee extension power. The second game involved controlling quadriceps muscular power to simulate flying an aeroplane in order to record accuracy of muscle activation. The subjects evaluated this game by completing a simple questionnaire.

RESULTS

No technical problem was encountered during the usage of this device. No subjects complained of any discomfort after using this device. Measurements including maximum knee extension power, knee muscle activation and control were recorded successfully. Subjects rated their experience with the device as either excellent or very good and agreed that the device can motivate and monitor the progress of knee rehabilitation training.

CONCLUSION

To the best of our knowledge, this is the first android-based tool available to fast track knee rehabilitation training. All subjects gave very positive feedback to this computer game aided knee device.

Semi-automated extraction and characterization of Stromal Vascular Fraction using a new medical device

INTRODUCTION

The stem cell rich Stromal Vascular Fraction (SVF) can be harvested by processing lipo-aspirate or fat tissue with an enzymatic digestion followed by centrifugation. To date neither a standardised extraction method for SVF nor a generally admitted protocol for cell application in patients exists. A novel commercially available semi-automated device for the extraction of SVF promises sterility, consistent results and usability in the clinical routine. The aim of this work was to compare the quantity and quality of the SVF between the new system and an established manual laboratory method.

MATERIAL AND METHODS

SVF was extracted from lipo-aspirate both by a prototype of the semi-automated UNiStation™ (NeoGenesis, Seoul, Korea) and by hand preparation with common laboratory equipment. Cell composition of the SVF was characterized by multi-parametric flow-cytometry (FACSCanto-II, BD Biosciences). The total cell number (quantity) of the SVF was determined as well the percentage of cells expressing the stem cell marker CD34, the leucocyte marker CD45 and the marker CD271 for highly proliferative stem cells (quality).

RESULTS

Lipo-aspirate obtained from six patients was processed with both the novel device (d) and the hand preparation (h) which always resulted in a macroscopically visible SVF. However, there was a tendency of a fewer cell yield per gram of used lipo-aspirate with the device (d: 1.1×105±1.1×105 vs. h: 2.0×105±1.7×105; p = 0.06). Noteworthy, the percentage of CD34+ cells was significantly lower when using the device (d: 57.3% ±23.8% vs. h: 74.1% ±13.4%; p = 0.02) and CD45+ leukocyte counts tend to be higher when compared to the hand preparation (d: 20.7% ±15.8% vs. h: 9.8% ±7.1%; p = 0.07). The percentage of highly proliferative CD271+ cells was similar for both methods (d:12.9% ±9.6% vs. h: 13.4% ±11.6%; p = 0.74) and no differences were found for double positive cells of CD34+/CD45+ (d: 5.9% ±1.7% vs. h: 1.7% ±1.1%; p = 0.13), CD34+/CD271+ (d: 24.1% ±12.0% vs. h: 14.2% ±8.5%; p = 0.07).

DISCUSSION

The semi-automated closed system provides a considerable amount of sterile SVF with high reproducibility. Furthermore, the SVF extracted by both methods showed a similar cell composition which is in accordance with the data from literature. This semi-automated device offers an opportunity to take research and application of the SVF one step further to the clinic.

A systematic examination of the bone destruction pattern of the two-shot technique

Introduction:

The two-shot technique is an effective stopping power method. The precise mechanisms of action on the bone and soft-tissue structures of the skull; however, remain largely unclear. The aim of this study is to compare the terminal ballistics of the two-shot and single-shot techniques.

Materials and Methods:

40 fresh pigs’ heads were randomly divided into 4 groups (n = 10). Either a single shot or two shots were fired at each head with a full metal jacket or a semi-jacketed bullet. Using thin-layer computed tomography and photography, the diameter of the destruction pattern and the fractures along the bullet path were then imaged and assessed.

Results:

A single shot fired with a full metal jacket bullet causes minor lateral destruction along the bullet path. With two shots fired with a full metal jacket bullet, however, the maximum diameter of the bullet path is significantly greater (P < 0.05) than it is with a single shot fired with a full metal jacket bullet. In contrast, the maximum diameter with a semi-jacketed bullet is similar with the single-shot and two-shot techniques.

Conclusion:

With the two-shot technique, a full metal jacket bullet causes a destruction pattern that is comparable to that of a single shot fired with a semi-jacketed bullet.

Thromboelastometry guided therapy of severe bleeding. Essener Runde algorithm

Both, severe haemorrhage and blood transfusion are associated with increased morbidity and mortality. Therefore, it is of particular importance to stop perioperative bleeding as fast and as possible to avoid unnecessary transfusion. Viscoelastic test (ROTEM® or TEG®) allow for early prediction of massive transfusion and goal-directed therapy with specific haemostatic drugs, coagulation factor concentrates, and blood products. Growing consensus points out, that plasma-based coagulation screening tests like aPTT and PT are inappropriate for monitoring coagulopathy or guide transfusion therapy. Increasing evidence of more than 5000 surgical or trauma patients points towards the beneficial effects of a thrombelastography or -metry based approach in diagnosis and goal-directed therapy of perioperative massive haemorrhage. The Essener Runde task force is a group of clinicians of various specialties (anaesthesiology, intensive care, haemostaseology, haematology, internal medicine, transfusion medicine, surgery) interested in perioperative coagulation management. The ROTEM diagnostic algorithm of the Essener Runde task force was created to standardise and simplify the interpretation of ROTEM® results in perioperative settings and to present their possible implications for therapeutic interventions in severe bleeding. To exemplify, this text mainly focuses on coagulation management in trauma.

Isovolaemic hemodilution with gelatin and hydroxyethylstarch 130/0.42: effects on hemostasis in piglets

OBJECTIVES

Artificial colloids, frequently used to prevent hemorrhagic shock in children, impair blood coagulation. To determine the impact of acute isovolaemic hemodilution with artificial colloids on clot formation, we conducted an experimental study in a pediatric animal model.

METHODS

Fifteen piglets underwent hemorrhage by withdrawing 40 ml·kg(-1) of blood volume in steps of 10 ml·kg(-1) each within 1 hour. After each withdrawal, the blood loss was randomly compensated by administering 4% gelatin (GEL) or hydroxylethyl starch 130/0.42 (HES) in a ratio of 1 : 1, or isotonic crystalloid solution (ICS) in a ratio of 1 : 4 for isovolaemic hemodilution. Quality of clot formation and platelet function was measured using Thrombelastometry (ROTEM(®)) and Multiple electrode impedance aggregometry (Multiplate(®)) after 10, 20, and 40 ml·kg(-1) blood replacement.

RESULTS

Moderate hemodilution (10-20 ml·kg(-1) blood replacement) caused no significant differences among groups (e.g. INTEM(®)-MCF after 20 ml·kg(-1) blood replacement (ICS vs GEL vs HES, P > 0.05). Profound hemodilution with 40 ml·kg(-1) blood replacement showed a significant difference between ICS and both colloids (P < 0.05), but no significant differences between GEL and HES.

CONCLUSIONS

Impairment of clot formation by moderate isovolaemic hemodilution did not significantly differ between ICS, GEL, and HES. Profound hemodilution of more than 50% of the estimated blood volume with GEL and HES caused significant impairment of clot formation in comparison to ICS and has to be considered when using high amounts of these synthetic colloids.

Haemostatic therapy in coronary artery bypass graft patients with decreased platelet function: comparison of fibrinogen concentrate with allogeneic blood products

BACKGROUND

Patients undergoing coronary artery bypass grafting (CABG) are at risk of postoperative bleeding because of decreased platelet function and cardiopulmonary bypass (CPB)-induced haemostatic impairment. Fibrinogen concentration decreases by 34-42% of the preoperative level by the end of CPB. An inverse relationship between perioperative plasma fibrinogen levels and postoperative bleeding has been reported in CABG patients. Administration of fibrinogen concentrate after weaning from CPB in patients with diffuse microvascular bleeding may help promote haemostasis. We compared patient outcomes following fibrinogen concentrate administration or transfusion of allogeneics in CABG patients with decreased platelet function.

METHODS

Thirty-eight patients with decreased preoperative platelet function in Multiplate aggregometry were included. Patients with bleeding after CPB received either fibrinogen concentrate (guided by the measurement of fibrin clot quality using the FIBTEM thromboelastometric test) or allogeneics.

RESULTS

Twenty-nine of 38 patients received haemostatic therapy (bleeding + fibrinogen group, n = 10; bleeding + allogeneics group, n = 19). Total transfusion (median (interquartile range)) was significantly lower in the bleeding + fibrinogen group (0 (0, 3.8) units), compared with the bleeding + allogeneics group (6 (5, 8) units, p = 0.0073). Bolus administration of fibrinogen concentrate increased FIBTEM maximum clot firmness from 10.5 (9.3, 11) mm after CPB to 20.5 (20, 21.8) mm at the end of surgery. Postoperative outcomes were similar in both groups. No treatment-related complications were observed after fibrinogen concentrate.

CONCLUSIONS

In CABG patients with bleeding after CPB, FIBTEM-guided administration of fibrinogen concentrate resulted in overall decreased transfusion, compared with haemostatic therapy with allogeneics. Fibrinogen concentrate administration increased the fibrin clot quality and helped achieve haemostasis.

Platelet function following trauma. A multiple electrode aggregometry study

Platelets play a central role in coagulation. Currently, information on platelet function following trauma is limited. We performed a retrospective analysis of patients admitted to the emergency room (ER) at the AUVA Trauma Centre, Salzburg, after sustaining traumatic injury. Immediately after admission to the ER, blood was drawn for blood cell counts, standard coagulation tests, and platelet function testing. Platelet function was assessed by multiplate electrode aggregometry (MEA) using adenosine diphosphate (ADPtest), collagen (COLtest) and thrombin receptor activating peptide-6 (TRAPtest) as activators. The thromboelastometric platelet component, measuring the contribution of platelets to the elasticity of the whole-blood clot, was assessed using the ROTEM device. The study included 163 patients, 79.7% were male, and the median age was 43 years. The median injury severity score was 18. Twenty patients (12.3%) died. Median platelet count was significantly lower among non-survivors than survivors (181,000/μl vs. 212,000/μl; p=0.01). Although platelet function defects were relatively minor, significant differences between survivors and non-survivors were observed in the ADPtest (94 vs. 79 U; p=0.0019), TRAPtest (136 vs. 115 U; p<0.0001), and platelet component (134 vs.103 MCEEXTEM - MCEFIBTEM; p=0.0012). Aggregometry values below the normal range for ADPtest and TRAPtest were significantly more frequent in non-survivors than in survivors (p=0.0017 and p=0.0002, respectively). Minor decreases in platelet function upon admission to the ER were a sign of coagulopathy accompanying increased mortality in patients with trauma. Further studies are warranted to confirm these results and investigate the role of platelet function in trauma haemostatic management.

Transfusion in trauma: thromboelastometry-guided coagulation factor concentrate-based therapy versus standard fresh frozen plasma-based therapy

INTRODUCTION

Thromboelastometry (TEM)-guided haemostatic therapy with fibrinogen concentrate and prothrombin complex concentrate (PCC) in trauma patients may reduce the need for transfusion of red blood cells (RBC) or platelet concentrate, compared with fresh frozen plasma (FFP)-based haemostatic therapy.

METHODS

This retrospective analysis compared patients from the Salzburg Trauma Centre (Salzburg, Austria) treated with fibrinogen concentrate and/or PCC, but no FFP (fibrinogen-PCC group, n = 80), and patients from the TraumaRegister DGU receiving ≥ 2 units of FFP, but no fibrinogen concentrate/PCC (FFP group, n = 601). Inclusion criteria were: age 18-70 years, base deficit at admission ≥ 2 mmol/L, injury severity score (ISS) ≥ 16, abbreviated injury scale for thorax and/or abdomen and/or extremity ≥ 3, and for head/neck < 5.

RESULTS

For haemostatic therapy in the emergency room and during surgery, the FFP group (ISS 35.5 ± 10.5) received a median of 6 units of FFP (range: 2, 51), while the fibrinogen-PCC group (ISS 35.2 ± 12.5) received medians of 6 g of fibrinogen concentrate (range: 0, 15) and 1200 U of PCC (range: 0, 6600). RBC transfusion was avoided in 29% of patients in the fibrinogen-PCC group compared with only 3% in the FFP group (P< 0.001). Transfusion of platelet concentrate was avoided in 91% of patients in the fibrinogen-PCC group, compared with 56% in the FFP group (P< 0.001). Mortality was comparable between groups: 7.5% in the fibrinogen-PCC group and 10.0% in the FFP group (P = 0.69).

CONCLUSIONS

TEM-guided haemostatic therapy with fibrinogen concentrate and PCC reduced the exposure of trauma patients to allogeneic blood products.

Thromboelastometry (TEM) findings in disseminated intravascular coagulation in a pig model of endotoxinemia

Standard coagulation tests have a low specificity and sensitivity for diagnosing disseminated intravascular coagulation. The aim of this study was to determine whether whole blood thromboelastometry (TEM) detects lipopolysaccharide (LPS)-induced changes in coagulation. Blood samples from 10 pigs were drawn at baseline, before and at the end of LPS infusion and 2, 3, 4 and 5 h after the start of endotoxinemia. Simultaneous to TEM, standard coagulation tests and extended coagulation analysis including tissue plasminogen activator (t-PA) and plasminogen activator inhibitor 1 (PAI-1) were performed. Endotoxinemia resulted in a significant acceleration of the nonactivated TEM (NATEM) clotting time 2 h after the end of LPS infusion; in contrast, the changes in international normalized ratio and activated partial thromboplastin time suggested delayed initiation of coagulation. NATEM maximum clot firmness (MCF) and fibrin-based thromboelastometry test (FIBTEM)-MCF decreased significantly from baseline until the last time point (from 64.6 ± 7.8 and 35.1 ± 12.8 mm to 52.8 ± 4.6 and 21.4 ± 11.8 mm, respectively; P = 0.01 for both parameters). A sharp, transient increase of t-PA had no effect on maximum lysis in the NATEM test. PAI-1 increased significantly 3 h after the start of LPS infusion, paralleled by a decrease in maximum lysis. In conclusion, TEM was superior to standard coagulation tests in reflecting initial activation of coagulation during endotoxinemia. TEM further suggested consumption of coagulation substrate; at the same time, inhibition of plasminogen activation was accompanied by improved clot stability. Further investigations are necessary to establish the clinical relevance of these findings.

[Platelet function analysis with point-of-care methods]

BACKGROUND

More and more patients are treated with antiplatelet drugs today. In this context a sufficient inhibition of platelet aggregation, on the one hand, is of essential importance to the efficiency of prophylaxis of myocardial and cerebral infarction and to avoiding thrombosis of drug-eluting stents. On the other hand, this medication can result in an increased risk of perioperative bleeding. In both situations control of the efficiency of therapy or rather the assessment of the impairment of hemostasis is of vital importance.

METHODS

Platelet function analyzer (PFA-100), multiple platelet function analyzer (Multiplate), and rotational thrombelastometry (ROTEM) are reliable and easy to use point-of-care (POC) devices. Since these three analyzers monitor different aspects of platelet function and have different limitations, the selection of the right test system depends on the right question.

RESULTS

PFA-100 enables a sensitive detection of von Willebrand's syndrome. Multiplate is apt to control efficiency of platelet inhibiton with acetylsalicylic acid, clopidogrel and glycoprotein IIb/IIIa receptor antagonists. ROTEM analysis offers the opportunity to assess hemostasis as a holistic system. Thereby, ROTEM analysis particularly detects hyperfibrinolysis, heparin effects, and fibrinogen-platelet interaction.

CONCLUSION

Due to their easy handling the described POC devices are applicable to perioperative coagulation management as well as during and after coronary intervention or to monitoring of platelet function in cardiologic practice. They enable a quick assessment of platelet function and an individually guided therapy.

Less impairment of hemostasis and reduced blood loss in pigs after resuscitation from hemorrhagic shock using the small-volume concept with hypertonic saline/hydroxyethyl starch as compared to administration of 4% gelatin or 6% hydroxyethyl starch solution

BACKGROUND

Small-volume resuscitation using hypertonic saline/hydroxyethyl starch 200/0.62 (HS-HES) has been shown to be an effective alternative to the administration of crystalloids or colloids in trauma patients. All i.v. fluids cause dose-related dilutional coagulopathy and show intrinsic effects on the hemostatic system, but only few data refer to functional consequences after small-volume resuscitation.

METHODS

Using thrombelastometry (ROTEM), we studied 30 pigs (weighing 35-45 kg) after withdrawal of 60% of blood volume [1484 mL (1369-1624 mL)] and receiving 4 mL/kg HS-HES for compensation of blood loss or 4% gelatin or 6% HES 130/0.4 in a 1:1 ratio to lost blood volume. To compare the ROTEM variables (coagulation time, clot formation time, alpha angle, clot firmness, and fibrinogen polymerization) with bleeding tendency, a hepatic incision was made and blood loss was measured.

RESULTS

Median (25th, 75th percentile) fibrinogen polymerization was significantly higher after HS-HES infusion [11 mm (10, 11), P = 0.0034] when compared with administration of 4% gelatin [4.5 mm (3.0, 5.8)] or HES 130/0.4 [3.5 mm (2.3, 4.0)]. Median blood loss after liver incision was 725 mL (900, 375) after HS-HES, 1625 mL (1275, 1950) after 4% gelatin, and 1600 mL (1500, 1800) after 6% HES 130/0.4 (P = 0.004). Hemodynamic stabilization was traceable in all groups but showed differences regarding filling pressures.

CONCLUSIONS

Resuscitation from hemorrhagic shock with HS-HES 200/0.62 results in less impairment of clot formation when compared with compensation of blood loss by administering 6% HES 130/0.4 or 4% gelatin.

Substitution of cyclophosphamide and busulfan by fludarabine, treosulfan and melphalan in a preparative regimen for children and adolescents with Shwachman–Diamond syndrome

Allogeneic hematopoietic stem cell transplantation (HSCT) is the only definitive treatment for severe bone marrow dysfunction and clonal disorders in patients diagnosed with Shwachman-Diamond syndrome (SDS). In an attempt to minimize regimen-related toxicity (RRT), we have initiated a fludarabine/treosulfan/melphalan-based pilot protocol avoiding the combination of busulfan and cyclophosphamide. Median age at transplantation was 9.6 years (range 1.5-17 years). All three patients received conditioning with fludarabine (30 mg/m2/day x 6), treosulfan (12 g/m2/day x 3) and melphalan (140 mg/m2/day x 1). CAMPATH-1H (0.1 mg/kg x 2) was added in two cases, while rabbit ATG (Genzyme; 3 x 2.5 mg/kg) was given to the cord blood recipient. One patient was transplanted with a non-manipulated marrow graft from an HLA-identical sibling, one with a marrow graft from a 10/10 matched unrelated donor, and one with a 9/10 matched unrelated umbilical cord blood (UCB) unit. Mean cell doses given were 3.6 x 10(8) nucleated cells/kg BW for the bone marrow recipients and 4.2 x 10(7) nucleated cells/kg BW for UCB recipient. Overall, two of three patients are alive and display 100% donor chimerism. Acute graft-versus-host disease grade II was seen in one patient, while no GVHD exceeding grade I occurred in the remaining two.

Measuring the angular dependent energy distribution of backscattered electrons at variable geometry

An aluminium semisphere system with 120 points of entry and eight detection areas, assembled on a meridian covering 0.0026 steradian each, was put over a solid bulk sample (e.g., aluminium), which was mounted in the eucentric point so that the incident electron beam could be varied by a polar rotation of the sphere in steps of 11.25 degrees. The complete angular distribution of the backscattered electrons became available by a rotation in steps of 11.25 degrees azimuthally. For this particular setup, the signals from the detection areas as well as the signal from the rest of the semisphere were amplified by operational amplifiers (Burr-Brown OPA128LM). However the signal of the semisphere was not available at that time. Specimen current measurements made the total amount of electrons accessible, providing a possibility for normalization of the results and comparison with total backscattering coefficients. By use of counter voltage variable up to 10 kV inside the detection assembly, it was possible to measure an energy resolution of the backscattered electrons for each detection area at the same time. Details of the construction and calibration procedures, possible errors, and sources of systematic deviations as well as first test results are discussed.

Tight and loose shapes in flat entangled dense polymers

We investigate the effects of topological constraints (entanglements) on two-dimensional polymer loops in the dense phase, and at the collapse transition (theta-point). Previous studies have shown that in the dilute phase the entangled region becomes tight, and is thus localised on a small portion of the polymer. We find that the entropic force favouring tightness is considerably weaker in dense polymers. While the simple figure-eight structure, created by a single crossing in the polymer loop, localises weakly, the trefoil knot and all other prime knots are loosely spread out over the entire chain. In both the dense and theta conditions, the uncontracted-knot configuration is the most likely shape within a scaling analysis. By contrast, a strongly localised figure-eight is the most likely shape for dilute prime knots. Our findings are compared to recent simulations.

Assessment of lung ventilation by MR imaging: current status and future perspectives

The aim of this paper is to review the present status of novel MRI techniques as a new important instrument for functional ventilation imaging. The current status and future perspectives in research and clinical applications are summarized. Morphological lung imaging is based on chest radiography and computed tomography, whereas scintigraphy is used for ventilation imaging. During recent years, MRI has emerged as a new means for functional imaging of ventilation. Aerosolized contrast agents and oxygen are used in proton imaging, whereas non-proton imaging relies on fluorine compounds, such as sulfur hexafluoride and perfluorcarbons, or on hyperpolarized noble gases, such as helium-3 or xenon-129. All the gases are administered as inhaled "contrast agents" for imaging of the airways and airspaces. In general, straightforward images demonstrate the homogeneity of ventilation in a breath-hold and allow for determination of ventilated lung. The different properties of the different compounds enable the measurement of additional functional parameters. They comprise airspace size, regional oxygen partial pressure, and analysis of ventilation distribution, ventilation/perfusion ratios, and gas exchange, including oxygen uptake. Novel MRI techniques provide the potential for functional imaging of ventilation. The next steps include definition of the value and the potential of the different contrast mechanisms as well as determination of the significance of the functional information with regard to physiological research and patient management in chronic obstructive pulmonary disease and others.

Probing the strong boundary shape dependence of the Casimir force

We study the geometry dependence of the Casimir energy for deformed metal plates by a path integral quantization of the electromagnetic field. For the first time, we give a complete analytical result for the deformation induced change in Casimir energy delta E in an experimentally testable, nontrivial geometry, consisting of a flat and a corrugated plate. Our results show an interesting crossover for delta E as a function of the ratio of the mean plate distance H, to the corrugation length lambda: For lambda<<H we find a slower decay approximately H(-4), compared to the H(-5) behavior predicted by the commonly used pairwise summation of van der Waals forces, which is valid only for lambda>>H.

[Dynamic imaging of the nasal cavity and the paranasal sinuses with polarized 3helium MRI]

PURPOSE

Reduced or blocked ventilation of the paranasal sinuses is probably the most important factor in the development of sinusitis. Recently, the use of optically polarized noble gas isotopes has attracted increasing interest for use in a variety of promising MR applications. The aim of this study was to test the feasibility of imaging and visualization ventilation of the nasal cavity and paranasal sinus in MR by inhalation of hyperpolarized (3)helium. The goal was to evaluate ventilation defects of the paranasal sinuses.

VOLUNTEERS AND METHODS

Three volunteers were enrolled in the study. (3)Helium was polarized to 40 - 50 % by direct optical pumping. 300 ml of 100 % (3)helium were administered in the left nasal vestibule through a glass tube. With a closed contralateral nasal vestibule, the Valsalva maneuver was performed twice. Using a dedicated application unit, which is also used in MR imaging of the lung, an exact amount of (3)helium gas was administered at the beginning of inspiration. Measurements were carried out on a clinical 1.5 T scanner. Coronal images of the nasal cavity and paranasal sinuses were acquired using ultrafast gradient-echo pulse sequence (TR = 2 ms, TE = 0.7 ms, FA < 2 degrees, 75 x 128, FOV = 500) with an image aquisition time of 130 ms.

RESULTS

The oral cavity and nasal cavities display a very high signal intensity after inhalation of polarized (3)helium gas. The signal intensity in the left maxillary sinus was higher compared to the right one. The mean signal intensity on the left side was 526 +/- 86 and on the right side 336 +/- 102. The left and right frontal sinus and ethmoid sinus only show signal of hyperpolarized (3)helium after two Valsalva maneuvers. Because of the low signal intensity of the frontal and ethmoid cells their visualization was incomplete. The signal to noise ratio was 14.1 for the left maxillary sinus, 8.9 for the right side, 6.3 for the left ethmoid sinus, 5.8 for the right side and 6.6 for the left frontal sinus and 7.8 for the right side.

CONCLUSION

(3)Helium MR allows imaging of the nasal cavity and the paranasal sinuses. Perhaps this method could be a new tool to visualize the ventilation of the maxillary sinus without ionizing radiation. Interpretations about the ventilation of the frontal and ethmoid cells remain speculative.

The Tasmanian children's project: the needs of children with a parent/carer with a mental illness

This paper presents some of the key findings and recommendations of the report The Tasmanian Children's Project (TCP): The Needs of Children with a Parent/Carer with a Mental Illness, October, 1999. The TCP, a collaborative venture between the University of Tasmania's School of Nursing and the Mental Health Services - South, Tasmania (Department of Health and Human Services), is the first study in Tasmania to formally examine the needs of children where the parent/carer has a mental illness. The study is a modified replication and extension of the 1993/94 Victorian Children's Project. Extension aspects of the TCP included interviews with children (in addition to parents and service providers), the inclusion of data on both maternal and paternal mental illness and a broad definition of mental illness (beyond psychotic illness and major affective disorder). The report highlights the need to provide a range of programs that encourage the development of personal competency among children, parents, and other family members and those that emphasize interagency collaboration. Implications of this research for mental health nursing education and practice are also addressed.

Quality of life influenced by primary surgical treatment for stage I-III breast cancer-long-term follow-up of a matched-pair analysis

BACKGROUND

Breast-conserving therapy has been demonstrated to be just as safe and a less disruptive experience compared with mastectomy for surgically manageable breast cancer. There is, however, no agreement in the literature about the impact of these procedures on several important aspects of quality of life (QOL). The purpose of the present study is to compare the long-term impact of these two surgical approaches on QOL in patients with identical tumor stages and to suggest possible shortcomings of the standard QOL questionnaires.

METHOD

Between August 1999 and May 2000, QOL questionnaires were answered by 152 pair-matched patients at the I. Frauenklinik, Ludwig-Maximilians University Munich, as part of routine follow-up examinations. The pairs of patients, each consisting of one patient after mastectomy and one after breast conservation, were selected according to the highest degree of equivalence in tumor stage. All patients had been initially treated for stage I-III breast cancer without evidence of distant metastases. The QOL was evaluated by using the QLQ-C30 questionnaire version 2.0 of the EORTC Study Group on Quality of Life. We formulated seven additional questions about the patients' satisfaction with the primary surgical treatment modality as viewed from their current perspective. The QOL questionnaires were answered after a median interval of 46 months following primary treatment.

RESULTS

Tumor stage, prognostic factors, and adjuvant systemic treatment were well balanced between the two groups. No differences between the two groups were observed in terms of all QOL items measured by the QLQ-C30. Our additional questions, however, revealed that patients in the mastectomy group were less satisfied with the cosmetic result of their primary operation (P < .0001), were more likely to feel basic changes in their appearance (P < .0001), and were more likely to be emotionally stressed by these facts (P < .0001). From their perspective at the time of completing the questionnaires, 11 patients in the mastectomy group (15%) would decide differently about the surgical treatment modality, compared with only 3 patients (4%) in the breast conservation group (P = .025).

CONCLUSION

While the primary surgical treatment modality seems to have no long-term impact on general QOL, certain body-image-related problems may be caused by mastectomy. Standard measuring instruments for QOL may fail to detect differences in satisfaction and adaptation with the primary surgical treatment modality.

Modified critical correlations close to modulated and rough surfaces

Correlation functions are sensitive to the presence of a boundary. Surface modulations give rise to modified near surface correlations, which can be measured by scattering probes. To determine these correlations, we develop a perturbative calculation in deformations in height from a flat surface. The results, combined with a renormalization group around four dimensions, are also used to predict critical behavior near a self-affine rough surface. We find that a large enough roughness exponent can modify surface critical behavior.

Polymer depletion interaction between two parallel repulsive walls

The depletion interaction between two parallel repulsive walls confining a dilute solution of long and flexible polymer chains is studied by field-theoretic methods. Special attention is paid to self-avoidance between chain monomers relevant for polymers in a good solvent. Our direct approach avoids the mapping of the actual polymer chains on effective hard or soft spheres. We compare our results with recent Monte Carlo simulations [A. Milchev and K. Binder, Eur. Phys. J. B 3, 477 (1998)] and with experimental results for the depletion interaction between a spherical colloidal particle and a planar wall in a dilute solution of nonionic polymers [D. Rudhardt, C. Bechinger, and P. Leiderer, Phys. Rev. Lett. 81, 1330 (1998)].

Critical adsorption on defects in ising magnets and binary alloys

Long-range correlations in a magnet close to its critical point or in a binary alloy close to a continuous order-disorder transition can substantially enhance the effect of local perturbations. It is demonstrated using a position-space renormalization procedure that quasi-one-dimensional defects which break the symmetry of the order parameter have pronounced effects: They cause long-range critical adsorption profiles and give rise to new universal critical exponents, which are identified and calculated using field-theoretical methods.

Critical adsorption near edges

Symmetry breaking surface fields give rise to nontrivial and long-ranged order parameter profiles for critical systems such as fluids, alloys, or magnets confined to wedges. We discuss the properties of the corresponding universal scaling functions of the order parameter profile and the two-point correlation function, and determine the critical exponents eta(parallel) and eta( perpendicular) for the so-called normal transition.

Polymer depletion effects near mesoscopic particles

The behavior of mesoscopic particles dissolved in a dilute solution of long, flexible, and nonadsorbing polymer chains is studied by field-theoretic methods. For spherical and cylindrical particles the solvation free energy for immersing a single particle in the solution is calculated explicitly. Important features are qualitatively different for self-avoiding polymer chains as compared with ideal chains. The results corroborate the validity of the Helfrich-type curvature expansion for general particle shapes and allow for quantitative experimental tests. For the effective interactions between a small sphere and a wall, between a thin rod and a wall, and between two small spheres, quantitative results are presented. A systematic approach for studying effective many-body interactions is provided. The common Asakura-Oosawa approximation modeling the polymer coils as hard spheres turns out to fail completely for small particles and still fails by about 10% for large particles.

Critical adsorption on curved objects

A systematic field-theoretical description of critical adsorption on curved objects such as spherical or rodlike colloidal particles immersed in a fluid near criticality is presented. The temperature dependence of the corresponding order parameter profiles and of the excess adsorption are calculated explicitly. Critical adsorption on elongated rods is substantially more pronounced than on spherical particles. It turns out that, within the context of critical phenomena in confined geometries, critical adsorption on a microscopically thin "needle" represents a distinct universality class of its own. Under favorable conditions the results are relevant for the flocculation of colloidal particles.

Effect of synthetic matrix-metalloproteinase inhibitors on invasive capacity and proliferation of human malignant gliomas in vitro

Glioma invasion into the surrounding brain tissue is still a major obstacle for any therapeutical approach. As in other solid tumors, matrix-metalloproteases (MMPs) have been suggested as being involved. The aim of this study was to evaluate whether the use of MMP inhibitors to target the protease-mediated invasion process could be a feasible approach. Two human cell lines (U251 and GaMG) and surgical specimens of 6 patients with malignant gliomas were grown as monolayers and spheroid cultures respectively. MMP- and u-PA-mRNA expression was investigated by semi-quantitative RT-PCR. Invasion was studied in Matrigel-coated Boyden chamber transwell assays for monolayers and in confrontation cultures of tumor spheroids with fetal rat brain aggregates in the presence of the synthetic MMP inhibitors batimastat (BB-94) and marimastat (BB-2516). Cytotoxicity/cytostatic effects of high concentrations of both compounds were assessed by growth curves, MTT assays and flow cytometry in human glioma cell lines. Batimastat and marimastat revealed a cytostatic effect at high concentrations (above 1 microM) without cytotoxicity. Both MMP inhibitors effectively reduced glioma invasion in Boyden-chamber assays at low concentrations of 0.3 microM. In confrontation cultures, concentrations of 10 microM and above were necessary to reduce invasion. This effect was observable with inter-individual heterogeneity in the patient's tumor material. MMP inhibitors effectively reduce glioma invasion, although high concentrations were required in 3-dimensional culture systems. At these concentrations, both compounds revealed a cytostatic, but no cytotoxic effect. Thus, high local concentrations of MMP inhibitors could offer a new therapeutic strategy for the treatment of gliomas.

Effect of synthetic matrix-metalloproteinase inhibitors on invasive capacity and proliferation of human malignant gliomas in vitro

Glioma invasion into the surrounding brain tissue is still a major obstacle for any therapeutical approach. As in other solid tumors, matrix-metalloproteases (MMPs) have been suggested as being involved. The aim of this study was to evaluate whether the use of MMP inhibitors to target the protease-mediated invasion process could be a feasible approach. Two human cell lines (U251 and GaMG) and surgical specimens of 6 patients with malignant gliomas were grown as monolayers and spheroid cultures respectively. MMP- and u-PA-mRNA expression was investigated by semi-quantitative RT-PCR. Invasion was studied in Matrigel-coated Boyden chamber transwell assays for monolayers and in confrontation cultures of tumor spheroids with fetal rat brain aggregates in the presence of the synthetic MMP inhibitors batimastat (BB-94) and marimastat (BB-2516). Cytotoxicity/cytostatic effects of high concentrations of both compounds were assessed by growth curves, MTT assays and flow cytometry in human glioma cell lines. Batimastat and marimastat revealed a cytostatic effect at high concentrations (above 1 microM) without cytotoxicity. Both MMP inhibitors effectively reduced glioma invasion in Boyden-chamber assays at low concentrations of 0.3 microM. In confrontation cultures, concentrations of 10 microM and above were necessary to reduce invasion. This effect was observable with inter-individual heterogeneity in the patient's tumor material. MMP inhibitors effectively reduce glioma invasion, although high concentrations were required in 3-dimensional culture systems. At these concentrations, both compounds revealed a cytostatic, but no cytotoxic effect. Thus, high local concentrations of MMP inhibitors could offer a new therapeutic strategy for the treatment of gliomas.

The cytomorphological spectrum of mantle cell lymphoma is reflected by distinct biological features

Mantle cell (centrocytic) non-Hodgkin's lymphoma (MCL) is a malignant tumour with unique biological features. The pathogenesis of MCL seems to be strongly associated with aberrant function of the cell cycle. 110 cases of MCL have been analysed for their cytomorphological features, mitotic and proliferation indices, bcl-1 rearrangements, p53 expression patterns and DNA content by both interphase cytogenetic as well as DNA flow cytometric analyses. According to cytomorphology, three subtypes were recognized: a common, a lymphoblastoid and a pleomorphic variant of MCL. Blastic MCL subtypes were characterized by distinctly elevated mitotic and proliferation indices, frequent bcl-1 rearrangements at the MTC locus, and overexpression of p53. The most interesting finding, however, was a striking tendency of blastoid MCL subtypes to harbour chromosome numbers in the tetraploid range, a feature clearly separating these neoplasms from other types of B-cell NHL and possibly being related to its unphysiological expression of cyclin D1. Although characterised by a uniform immunophenotype and common biological background, MCL shows a broad spectrum of morphological features ranging from small cell to blastic types, and this spectrum is mirrored by distinct biological features.