Development of phantom materials with independently adjustable CT- and MR-contrast at 0.35, 1.5 and 3 T

Quality assurance in magnetic resonance (MR)-guided radiotherapy lacks anthropomorphic phantoms that represent tissue-equivalent imaging contrast in both computed tomography (CT) and MR imaging. In this study, we developed phantom materials with individually adjustable CT value as well as [Formula: see text]- and [Formula: see text]-relaxation times in MR imaging at three different magnetic field strengths. Additionally, their experimental stopping power ratio (SPR) for carbon ions was compared with predictions based on single- and dual-energy CT. Ni-DTPA doped agarose gels were used for individual adjustment of [Formula: see text] and [Formula: see text] at [Formula: see text] and 3.0 T. The CT value was varied by adding potassium chloride (KCl). By multiple linear regression, equations for the determination of agarose, Ni-DTPA and KCl concentrations for given [Formula: see text] [Formula: see text] and CT values were derived and employed to produce nine specific soft tissue samples. Experimental [Formula: see text] [Formula: see text] and CT values of these soft tissue samples were compared with predictions and additionally, carbon ion SPR obtained by range measurements were compared with predictions based on single- and dual-energy CT. The measured CT value, [Formula: see text] and [Formula: see text] of the produced soft tissue samples agreed very well with predictions based on the derived equations with mean deviations of less than [Formula: see text] While single-energy CT overestimates the measured SPR of the soft tissue samples, the dual-energy CT-based predictions showed a mean SPR deviation of only [Formula: see text] To conclude, anthropomorphic phantom materials with independently adjustable CT values as well as [Formula: see text] and [Formula: see text] relaxation times at three different magnetic field strengths were developed. The derived equations describe the material specific relaxation times and the CT value in dependence on agarose, Ni-DTPA and KCl concentrations as well as the chemical composition of the materials based on given [Formula: see text] and CT value. Dual-energy CT allows accurate prediction of the carbon ion range in these materials.

Methodology paper: a novel phantom setup for commissioning of scanned ion beam delivery and TPS

BACKGROUND

Commissioning of treatment planning systems (TPS) and beam delivery for scanned light ion beams is an important quality assurance task. This requires measurement of large sets of high quality dosimetric data in anthropomorphic phantoms to benchmark the TPS and dose delivery under realistic conditions.

METHOD

A novel measurement setup is described, which allows for an efficient collection of a large set of accurate dose data in complex phantom geometries. This setup allows dose measurements based on a set of 24 small volume ionization chambers calibrated in dose to water and mounted in a holder, which can be freely positioned in a water phantom with various phantoms mounted in front of the water tank. The phantoms can be scanned in a CT and a CT-based treatment planning can be performed for a direct benchmark of the dose calculation algorithm in various situations.

RESULTS

The system has been used for acceptance testing in scanned light ion beam therapy at Heidelberg Ion Beam Therapy Center for scanned proton and carbon ion beams. It demonstrated to be useful to collect large amounts of high quality data for comparison with the TPS calculation using various phantom geometries.

CONCLUSION

The setup is an efficient tool for commissioning and verification of treatment planning systems. It is especially suited for dynamic beam delivery, as many data points can be obtained during a single plan delivery, but can be adapted also for other dynamic therapies, like rotational IMRT.

Significantly increased CD70 up regulation on TEL-AML positive B cell precursor acute lymphoblastic leukemia cells following CD40 stimulation

BACKGROUND

TEL-AML the most common genetic alteration in childhood precursor B acute lymphoblastic leukemia (BCP-ALL) is associated with a favorable prognosis.

PATIENTS AND METHOD

We studied the expression of nerve growth factor/tumor necrosis factor receptor (NGFR/TNFR)/ligand family members on 108 primary BCP-ALL samples by flow cytometry and compared both their baseline expression and CD40-induced modulation on TEL-AML positive and negative leukemia samples.

RESULTS

Our findings demonstrate that TEL-AML positive patients exhibit a significantly higher percentage of CD40, CD27 and p75NTR positive blasts at diagnosis. This might well contribute to the improved relapse-free survival of these patients assessed in Kaplan Meier analysis as CD27 and p75NTR directly mediate apoptotic signals. Furthermore CD40 ligation enhances antigen presenting and T cell stimulatory capacity via significant up regulation of CD70 while adequate response to physiological maturation signals as indicated by concomitant down regulation of CD27 is retained in TEL-AML positive leukemia.

CONCLUSION

These data provide novel insights in immunological control mechanisms preserved in this leukemia subtype and suggest that not only treatment with chemicals such as HDAC inhibitors but also retained in vivo response to CD40 ligation contributes to improved immune surveillance in these patients which may add to a superior relapse-free survival observed particularly in the presence of other risk factors.

Plastin 3 ameliorates spinal muscular atrophy via delayed axon pruning and improves neuromuscular junction functionality

F-actin bundling plastin 3 (PLS3) is a fully protective modifier of the neuromuscular disease spinal muscular atrophy (SMA), the most common genetic cause of infant death. The generation of a conditional PLS3-over-expressing mouse and its breeding into an SMA background allowed us to decipher the exact biological mechanism underlying PLS3-mediated SMA protection. We show that PLS3 is a key regulator that restores main processes depending on actin dynamics in SMA motor neurons (MNs). MN soma size significantly increased and a higher number of afferent proprioceptive inputs were counted in SMAPLS3 compared with SMA mice. PLS3 increased presynaptic F-actin amount, rescued synaptic vesicle and active zones content, restored the organization of readily releasable pool of vesicles and increased the quantal content of the neuromuscular junctions (NMJs). Most remarkably, PLS3 over-expression led to a stabilization of axons which, in turn, resulted in a significant delay of axon pruning, counteracting poor axonal connectivity at SMA NMJs. These findings together with the observation of increased endplate and muscle fiber size upon MN-specific PLS3 over-expression suggest that PLS3 significantly improves neuromuscular transmission. Indeed, ubiquitous over-expression moderately improved survival and motor function in SMA mice. As PLS3 seems to act independently of Smn, PLS3 might be a potential therapeutic target not only in SMA but also in other MN diseases.

Severe SMA mice show organ impairment that cannot be rescued by therapy with the HDACi JNJ-26481585

Spinal muscular atrophy (SMA) is the leading genetic cause of early childhood death worldwide and no therapy is available today. Many drugs, especially histone deacetylase inhibitors (HDACi), increase SMN levels. As all HDACi tested so far only mildly ameliorate the SMA phenotype or are unsuitable for use in humans, there is still need to identify more potent drugs. Here, we assessed the therapeutic power of the pan-HDACi JNJ-26481585 for SMA, which is currently used in various clinical cancer trials. When administered for 64 h at 100 nM, JNJ-26481585 upregulated SMN levels in SMA fibroblast cell lines, including those from non-responders to valproic acid. Oral treatment of Taiwanese SMA mice and control littermates starting at P0 showed no overt extension of lifespan, despite mild improvements in motor abilities and weight progression. Many treated and untreated animals showed a very rapid decline or unexpected sudden death. We performed exploratory autopsy and histological assessment at different disease stages and found consistent abnormalities in the intestine, heart and lung and skeletal muscle vasculature of SMA animals, which were not prevented by JNJ-26481585 treatment. Interestingly, some of these features may be only indirectly caused by α-motoneuron function loss but may be major life-limiting factors in the course of disease. A better understanding of - primary or secondary - non-neuromuscular organ involvement in SMA patients may improve standard of care and may lead to reassessment of how to investigate SMA patients clinically.

Prevalence of velopharyngeal insufficiency in woodwind and brass students

BACKGROUND

Velopharyngeal insufficiency (VPI) is a disorder in which air leaks out through the nose, reducing performance quality and capacity in wind and brass players. There have been limited studies on the prevalence of this potentially career-threatening disorder.

AIMS

To identify the prevalence of VPI in a sample of conservatorium level woodwind and brass student instrumentalists in Australia.

METHODS

Wind and brass students from four music institutions were recruited by email invitation to complete an online survey. Results from 77 musicians were analysed for their knowledge and experience of VPI. Musicians who had experienced VPI provided information on the characteristics, symptoms and treatment or advice sought for the disorder.

RESULTS

Of the 77 musicians included in the analysis, 44% had heard of VPI, 30% were aware of other musicians who had experienced VPI and 39% had personally experienced VPI.

CONCLUSIONS

The results suggest that VPI may be a common occurrence in wind and brass players. Informal discussions with colleagues and music teachers also suggest that VPI is a frequent phenomenon. This group of musicians represents the largest sample surveyed about VPI to date.

Impact of bispectral index monitoring on postoperative delirium in patients undergoing aortic surgery

BACKGROUND

Bispectral index monitoring can facilitate anesthesia care. We evaluated the association of Bispectral index with postoperative neurological outcome and delirium in patients undergoing aortic surgery.

METHODS

From 2006 to 2009, 292 consecutive patients undergoing aortic surgery were retrospectively reviewed. Patients were classified into 5 groups according to Bispectral index reduction: Group I (≤15%), Group II (15-20%), Group III (20-25%), Group IV (25-30%), and Group V (>30%).

RESULTS

The number of patients in each group was : 52 (17.8%), Group I; 125 (42.8%), Group II;68 (23.3%), Group III; 33 (11.3%), Group IV; 14 (4.8%), Group V. The incidence of delirium and neurological events was higher in Group IV and Group V(90.9% and 18.2% in Group IV, and 71% and 79% in Group V; both p<0.001). Only Group V showed a longer intensive care unit stay compared to Group I (13.5±10.3 vs 5.4±6.6 days; p=0.002), Group II (7.3±8.6 days, p=0.005) and Group III (6.7±6.5 days, p=0.015). Group V also showed a longer intubation time compared to Group I (228±211 vs 73±112 hours; p=0.008) and Group II (105±177 hours, p=0.002).

CONCLUSIONS

Our data suggest a higher incidence of neurological deficits in patients with a Bispectral index reduction of >25% from baseline. Explanations for these findings are speculative with regard to the underlying mechanisms, and larger studies are warranted to clarify these issues.

SAHA ameliorates the SMA phenotype in two mouse models for spinal muscular atrophy

Proximal spinal muscular atrophy (SMA) is a common autosomal recessively inherited neuromuscular disorder determined by functional impairment of alpha-motor neurons within the spinal cord. SMA is caused by functional loss of the survival motor neuron gene 1 (SMN1), whereas disease severity is mainly influenced by the number of SMN2 copies. SMN2, which produces only low levels of full-length mRNA/protein, can be modulated by small molecules and drugs, thus offering a unique possibility for SMA therapy. Here, we analysed suberoylanilide hydroxamic acid (SAHA), a FDA-approved histone deacetylase inhibitor, as potential drug in two severe SMA mouse models each carrying two SMN2 transgenes: US-SMA mice with one SMN2 per allele (Smn(-/-);SMN2(tg/tg)) and Taiwanese-SMA mice with two SMN2 per allele (Smn(-/-);SMN2(tg/wt)), both on pure FVB/N background. The US-SMA mice were embryonically lethal with heterozygous males showing significantly reduced fertility. SAHA treatment of pregnant mothers rescued the embryonic lethality giving rise to SMA offspring. By using a novel breeding strategy for the Taiwanese model (Smn(-/-);SMN2(tg/tg) x Smn(-/+) mice), we obtained 50% SMA offspring that survive approximately 10 days and 50% control carriers in each litter. Treatment with 25 mg/kg twice daily SAHA increased lifespan of SMA mice by 30%, significantly improved motor function abilities, reduced degeneration of motor neurons within the spinal cord and increased the size of neuromuscular junctions and muscle fibers compared with vehicle-treated SMA mice. SMN RNA and protein levels were significantly elevated in various tissues including spinal cord and muscle. Hence, SAHA, which lessens the progression of SMA, might be suitable for SMA therapy.

her1 and her13.2 are jointly required for somitic border specification along the entire axis of the fish embryo

Delta-Notch and FGF signaling are involved in the control of somitogenesis in zebrafish. her genes are generally known as downstream targets of Delta-Notch signaling, but the her13.2 gene from zebrafish has recently been shown to depend on FGF signaling only. We have here studied the functional role of her13.2 in conjunction with her genes that are under Delta-Notch control. We show that joint inactivation of her1 and her13.2 leads to a complete loss of all somitic borders, including the most anterior ones. This somitic phenotype is much stronger than would be expected from the effects of the inactivation of either gene alone. A joint inactivation of her13.2 and her7, which is a paralogue of her1, does not show this enhanced effect. Thus, our results confirm inferences from in vitro studies that her1 and her13.2 form specific heterodimers, which may directly be required for regulating further target genes. These two her genes thus constitute the link between Delta-Notch pathway and FGF signaling during entire somitogenesis. We show that this interaction is conserved in the rice fish medaka, as a joint inactivation of the respective orthologues leads also to the same phenotype as in zebrafish. In addition, our results suggest that the mechanisms for anterior and posterior somite formation are not principally different, although the anterior somites often seem more refractory to genetic perturbations.

Collagen biosynthesis of mechanically loaded articular cartilage explants

OBJECTIVE

The purpose of this study was to investigate systematically the effect of load amplitudes, frequencies and load durations of intermittently applied mechanical pressure on the biosynthesis of collagen and non-collagenous proteins (NCP) as well as on the water content of cultured bovine articular cartilage explants.

METHODS

Cyclic compressive pressure was applied using a sinusoidal waveform of 0.5 Hz frequency with a peak stress of 0.1, 0.5 or 1.0 MPa for a period of 10s followed by a load-free period of 10, 100 or 1000s. These intermittent loading protocols were repeated for a total duration of 1, 3 or 6 days. During the final 18 h of experiments, the incorporation of [(3)H]-proline into collagen and NCP, the content of water as well as the deformation of loaded explants were determined.

RESULTS

Intermittently applied, cyclic mechanical loading of articular cartilage explants consistently reduced the relative rate of collagen synthesis compared to load-free conditions. This reduced proportion of newly synthesized collagen among newly made proteins was independent of the mechanical stimuli applied. The release of newly synthesized collagen and NCP from loaded explants into the nutrient media was unaffected by any of the loading protocols applied. In addition, quantitative data are provided showing that only high amplitudes of loads and frequencies enhanced the water content of the explants.

CONCLUSIONS

Previous studies reporting that osteoarthritic cartilage in vivo can synthesize elevated amounts of collagen imply that the loading protocols chosen were inadequate for simulating in vitro osteoarthritic-like alterations of collagen synthesis. In our experiments the collagen biosynthesis of chondrocytes was only minor responsive to alterations in mechanical stimuli, applied over a wide range. Thus, our results imply that the synthesis of these structural macromolecules is under the strict control of normal chondrocytes enabling them to maintain the shape of this physical demanded tissue.

[Assessment of the tetanus immune status in plasma donors of the Blood Donor Service of the Bavarian Red Cross]

BACKGROUND AND OBJECTIVE

Tetanus is nowadays largely under control, as a result of the preventive immunization programme. This prophylactic measure is important also because there is no specific treatment. In Germany tetanus occurs almost exclusively in elderly, not adequately immunized persons. This study determined the existing immune status of plasma donors in the region of Ingolstadt, Bavaria.

SUBJECTS AND METHODS

Tetanus IgG antibody concentrations were measured with the ELISA test in serum of 1742 plasma donors (891 women, 851 men, age range 18-64 years).

RESULTS

An adequately protective immunity against tetanus was found in 98.7% of men and 94.1% of women, while 5 women and 3 men had no protection. Demographic data indicated that the immunization protected males longer than females, regardless of age, especially in those over 50 years of age (85% of females, 99% of males).

CONCLUSION

Adequate tetanus protection was achieved in the overwhelming majority of test subjects. This demonstrates that the prevalence of protection is lower in females than in males, a difference most marked in those over 50 years of age. It is important that this age group in particular should, as part of health care, be informed by their medical practitioner of the dangers of tetanus and the advantages of immunization.

Characterization of CD34+ Progenitor-Derived Dendritic Cells Pulsed with Tumor Cell Lysate for a Vaccination Strategy in Children with Malignant Solid Tumors and a Poor Prognosis

BACKGROUND

Children and adolescents with primary multifocal, refractory or relapsed malignant extracranial solid tumors still have a poor prognosis inspite of intensive standard radio-/chemotherapy. Here complementary immunomodulatory treatment modalities may prove beneficial as consolidation therapy following cytoreduction. Neuroblastoma, Ewing tumor and soft tissue sarcoma cells have principally been shown to be susceptible towards both cytotoxic and humoral effector mechanisms. Yet in vivo they are not capable of inducing an effective antitumor response which has been attributed to low level MHC expression and lack of costimulatory surface molecules. Professional antigen - presenting cells such as dendritic cells (DCs) in contrast are capable of activating unprimed T cells and are therefore ideal tools for vaccine generation.

RESULTS

Here we demonstrate that DCs may be generated from CD34+ progenitor cells to clinical scale in a three to four week cell culture process including an initial expansion and subsequent differentiation and maturation steps. DCs derived from CD34+ progenitors express the expected marker profile and are highly effective in stimulating allogeneic T cell effectors. We also demonstrate that they effectively take up fluorescence-labelled tumor cell lysate.

DISCUSSION

Having established a cell culture process for clinical scale DC production utilizing CD34+ progenitors as the cellular source we discuss the role of CD34+ derived DCs in clinical vaccination protocols. The rationale for a phase I/II DC dose escalation study for high risk pediatric patients with extracranial solid tumors assessing safety, immunological and clinical efficacy of serial combined intranodal and subcutaneous injections of tumor cell lysate-pulsed autologous DCs is delineated.

[Open versus arthroscopic shoulder stabilization. An analysis of the treatment costs]

In this study the total costs of clinical open and arthroscopic anterior shoulder stabilization were evaluated, analyzed and compared. From 1988 to 1998 147 patients underwent open (Bankart) or arthroscopic (ASK) anterior shoulder stabilization. We randomized two groups of 30 patients for each method (Bankart: 25 male, 5 female, 29 years of age; ASK: 25 male, 5 female, 26 years of age) and evaluated the costs of their clinical treatment. The total cost was significantly ( p<0.05, Mann-Whitney U-Test) higher for the open (5639 euro) than for the arthroscopic (4601 euro) therapy. There was a significant difference between the groups for the average cost of surgery (Bankart: 2741 euro; ASK: 2315 euro, p<0.05) and the average postoperative treatment cost (Bankart: 2202 euro; ASK: 1630 euro, p<0.05) whereas the average preoperative treatment cost was not significantly different (Bankart: 669 euro, ASK: 657 euro). The staff costs for the surgical procedure (Bankart: 1800 euro (32%), ASK: 1319 euro (29%)) and the postoperative staff costs of the nurses (Bankart: 1271 euro (23%), ASK: 997 euro (22%)) represented the greatest parts of the total costs. The average duration of the clinical treatment was 15.8 days for the open- and 12,4 days for the arthroscopic group.

Collection, storage, and filtration of in vivo study samples using 96-well filter plates to facilitate automated sample preparation and LC/MS/MS analysis

The benefits of high-throughput bioanalysis within the pharmaceutical industry are well established. One of the most significant bottlenecks in bioanalysis is transferring in vivo-generated study samples from their collection tubes during sample preparation and extraction. In most cases, the plasma samples must be stored frozen prior to analysis, and the freeze/thaw (F/T) process introduces thrombin clots that are capable of plugging pipets and automated liquid-transfer systems. A new approach to dealing with this problem involves the use of Ansys Captiva 96-well 20-microm polypropylene filter plates to collect, store frozen, and filter plasma samples prior to bioanalysis. The samples are collected from the test subjects, and the corresponding plasma samples are placed directly into the wells of the filter plate. Two Duoseal (patent pending) covers are used to seal the top and bottom of the plate, and the plate is stored at down to -70 degrees C. Prior to sample analysis, the seals are removed and the plate is placed in a 96-well SPE manifold. As the plasma thaws, it passes (by gravity or mild vacuum) through the polypropylene filter into a 96-well collection plate. A multichannel pipet or automated liquid-transfer system is used to transfer sample aliquots without fear of plugging. A significant advantage of this approach is that, unlike other methods, issues related to incomplete pipetting are virtually eliminated. The entire process is rapid since thawing and filtering take place simultaneously, and if a second F/T cycle is required for reanalysis, it is not necessary to refilter the samples (additional clotting was not observed after three F/T cycles). This technique was tested using monkey, rat, and dog plasma and sodium heparin and EDTA anticoagulants. To assess the possibility of nonspecific binding to the polypropylene filter, a variety of drug candidates from diverse drug classes were studied. Validation data generated for two Lilly compounds from distinct classes, before and after filtering, are presented in this paper as practical examples of this technique. While LC/MS/MS is the primary method of bioanalysis in our laboratory, the technique presented in this paper is applicable to other forms of detection as well.

Determination of olanzapine in human blood by liquid chromatography-tandem mass spectrometry

A liquid chromatographic-tandem mass spectrometric (LC-MS-MS) assay was developed and validated to quantitatively determine olanzapine (OLZ) concentrations in human blood. Liquid-liquid extraction, using n-butanol:cyclohexane (3:47, v/v), was used to isolate OLZ and its internal standard, LY170158, from the biological matrix. Chromatographic resolution of OLZ from endogenous interferences and known metabolites was accomplished with a MetaChem Monochrom HPLC column (4.6 x 150 mm, d(p) 5 microm). Detection occurred using a Perkin-Elmer Sciex API III Plus triple quadrupole mass spectrometer using positive ion APCI and multiple reaction monitoring (MRM). The linear dynamic range was from 5 to 500 ng ml(-1) based on a 0.25-ml aliquot of human blood. The inter-day precision (%RSD) and accuracy (%RE) ranged from 3.65 to 10.64 and from -2.14 to 3.07, respectively. Modifications to an existing assay for the determination of OLZ in human plasma were necessary. A different structural analog was used as the internal standard due to instability observed for the original analog when using human blood as the matrix. A second modification was the addition of the anti-oxidant sodium ascorbate to inhibit degradation of OLZ in human blood, as has been noted by other investigators. Upon fortification of human blood with sodium ascorbate (final concentration, 0.33 mM), OLZ was found to be stable for at least 1 week at -70 degrees C as well as through two freeze-thaw cycles. This assay, which will be used to investigate the distribution of OLZ in human blood, grants insight into the proper sample handling conditions needed to perform valid determinations of OLZ in human blood.

[Valgus tibial head reconstruction, monocondylar sled prosthesis or bicondylar gliding surface replacement in therapy of medial gonarthrosis--a cost analysis]

AIM

Three to a certain extent competing methods for the treatment of unicompartmental osteoarthritis of the knee are compared regarding the costs they cause. These methods comprise the high tibial valgus osteotomy (HTO), the unicompartmental knee arthroplasty (UKA), and the total knee arthroplasty (TKA).

METHODS

We compared the in-patient costs and out-patient costs of 20 patients (drawn by lot) in each group who received one of the above-named operative methods at our hospital between 1988 and 1993. The results were extrapolated according to the expected survival rate of the applied method.

RESULTS

The average total costs of patients who received a HTO were 9.487,-; for the unicompartmental arthroplasty the average cost were 11.687,-; the implantation of a TKA resulted in average costs of 16.940,-. All operative procedures exceeded a particular global amount, the socalled "Fallpauschale".

CONCLUSION

Regarding the total costs that arise for the operative treatment of the degenerative arthritis of the knee, the HTO (with or without hardware removal) proves to be the cheapest of the applied methods. Projecting the results on the survival rate of each treatment method, no statistically significant differences could be recognized between the three operative procedures.

The effect of continuously applied cyclic mechanical loading on the fibronectin metabolism of articular cartilage explants

Articular cartilage serves primarily as a load-bearing material able to regulate its own metabolic activity in response to the mechanical stimuli applied. Fibronectin plays a critical role in the organization and function of the cartilage extracellular matrix. The purpose of this study was to investigate systematically the effect of load magnitude, frequency and duration of loading on the synthesis, content and release of fibronectin and proteins by mature bovine articular cartilage explants using a novel mechanical loading system. Increasing the load magnitude, as well as the duration of loading, inhibited the synthesis and content of fibronectin and proteins; the fibronectin synthesis was more specifically affected than the overall protein synthesis indicating that fibronectin is more responsive to pressure than synthesis of other proteins. Reducing the load frequency did not modulate the inhibitory effect of a given cyclic stress on synthesis and content of fibronectin and proteins even though explants were more compressed. The release of endogenous fibronectin was significantly reduced independent of the applied loading protocols when compared with unloaded controls. This study demonstrates that the magnitude and the duration of loading influences the degree of inhibition of fibronectin and protein synthesis, while loaded explants possess an elevated but limited capacity to bind fibronectin. Compared with other studies, our present results show that the applied load function in particular has a profound effect on the metabolism of chondrocytes.

Specific targeting of cytokine-secreting cells: a bispecific diabody recognizing human interleukin-6 and CD3 induces T cell-mediated killing

Cytokines have been implicated in the pathophysiology of many diseases. Although there have been many attempts to neutralize the activity of cytokines in vivo and in vitro, no strategies have been developed to specifically eliminate cells that overexpress cytokines. Considering the fact that cytokines in part remain cell associated on secretion, we have constructed a bispecific diabody consisting of a nonneutralizing scFv antibody recognizing human interleukin-6 (IL-6) and an scFv corresponding to the monoclonal antibody (mAb) OKT3, which recognizes and activates the human T cell receptor. Here we show that the diabody recognized both human IL-6 and human CD3. In the presence of human T cells, the diabody induced killing of human hepatoma cells that had been transfected with a human IL-6 cDNA. The extent of killing was dependent on the ratio of effector/target cells and increased with increasing concentrations of the diabody. Untransfected control cells or human hepatoma cells that secrete the IL-6-related cytokine leukemia inhibitory factor (LIF) remained unaffected. We conclude that diabodies recognizing cytokines can be used to specifically target cytokine-secreting cells.

[Perioperative cost analysis of cemented versus uncemented total hip endoprostheses for clinical and economic management. Postoperative follow-up study over one year]

QUESTIONS

Are there and what are the differences between in-patient and out-patient costs for cemented or noncemented hip prosthesis? How to make it possible to keep in-patient costs within the limit of the a special global amount ("Fallpauschale")?

METHODS

In this study we compared in-patient and out-patient costs of 30 patients with cemented and 30 patients with noncemented hip prosthesis during the first year after surgery. We developed a perioperative management in order to keep the costs in the limits of the "Fallpauschale".

RESULTS

The average in-patient cost for the cemented prosthesis group was DM 19.644,89 and for the non-cemented group DM 20.485,33. In both groups these costs went beyond the "Fallpauschale" (DM 18.643,80). Comparing the two groups we found significant differences in costs for the endoprosthesis and for laboratory costs. We discovered a suitable perioperative management to keep costs below the "Fallpauschale".

CONCLUSION

Using an appropriate perioperative management it is possible to keep costs in the given limits.

Intermittent cyclic loading of cartilage explants modulates fibronectin metabolism

OBJECTIVE

The aim of this study was to evaluate systematically the effect of tissue load, its amplitude, time of intermittence and duration of loading on the biosynthesis and release of fibronectin by intermittently loaded mature bovine articular cartilage explants.

METHODS

Cyclic compressive pressure was introduced using a sinusoidal waveform of 0.5 Hz-frequency with a peak stress of 0.1, 0.5 or 1.0 MPa for a period of 10 s followed by an unloaded period lasting 10, 100 or 1000 s. Fibronectin and total proteins were radiolabeled with 10 microCi/ml [3H]-phenylalanine during the final 18 h of the 1, 3 or 6 day experiments. The content of endogenous fibronectin was determined using enzyme-linked immunosorbant assay (ELISA), whereas the viability of explants was measured using sections of cartilage explants stained with fluorescein diacetate and propidium iodide. The deformation of loaded explants was determined using a load-displacement transducer system.

RESULTS

The mechanical factor time of intermittence significantly altered the synthesis and release of fibronectin by cartilage explants, whereas the tested range of load magnitudes, as well as the duration of loading, seemed to be of subordinate importance. Loading affected the viability of the superficial zone in the cartilage, whereas the chondrocytes of the intermediate and deep zone remained viable. The compression of loaded explants was dependent on the magnitude of stress, as well as on the duration of unloading between each loading cycle. Synthesis of fibronectin, the retention of newly synthesized fibronectin within the extracellular matrix, and the portion of newly synthesized proteins that were fibronectin was significantly increased in cartilage explants which were cyclically compressed with 0.5 MPa for 10 s followed by a period of unloading lasting 100 s.

CONCLUSIONS

Previous studies reporting that cartilage explants of human and animal osteoarthritic joints synthesize and retain elevated amounts of fibronectin imply that in our experiments mechanical stimuli can induce a fibronectin metabolism in vitro which mimics some of the osteoarthritic characteristics.

Enterobacteria-infected T cells as antigen-presenting cells for cytotoxic CD8 T cells: a contribution to the self-limitation of cellular immune reactions in reactive arthritis?

In enterobacteria-induced reactive arthritis (ReA), different T cell subsets play a role in the induction and maintenance of the synovitic process. Synovial fluid-derived alphabeta CD4, alphabeta CD8, and gammadelta T lymphocyte clones (TLC) that recognize Yersinia or Salmonella antigens on professional antigen-presenting cells (APC) have been characterized, and T cells themselves can function as nonprofessional APC. T cells were infected with the facultatively intracellular, arthritogenic enterobacterium Yersinia enterocolitica O:3. A CD8 TLC isolated from a patient with Yersinia-induced ReA recognized and efficiently lysed autologous and allogeneic Yersinia-infected T cells. Infected cytotoxic T lymphocytes (CTL) had a reduced lytic capacity against syngeneic and allogeneic infected target cells, suggesting that the infection of CTL by bacteria may represent a mechanism of immune escape. In ReA, antigen presentation by T cells may modify the antibacterial immune response and may also contribute to network control mechanisms of T cell-mediated cytotoxicity.

TCRB junctional regions from HLA-B27-restricted T cells and HLA-B27 binding peptides display conserved hydropathy profiles in the absence of primary sequence homology

Analysis of formal amino acid sequence identity between different TCRB chain (TCRB) hypervariable regions (CDR3) is commonly used to localize relevant sites of TCR antigen interaction or to yield indirect information on unknown corresponding antigens. However, this analysis sometimes fails to demonstrate expected concordances, e.g. between CDR3 from T cell clones of identical reactivity. Since this may be due to ignorance of physico-chemical parameters, we have now use hydropathy profile analysis as an additional method to examine TCRB-CDR3 and putative peptide antigens. Superimposed hydropathy plots (SHOP) of 20 TCRB-CDR3 from HLA-B27-restricted autoreactive and Yersinia enterocolitica-specific synovial cytotoxic T lymphocytes (CTL) isolated from patients with reactive arthritis (ReA) revealed restricted distribution of polar amino acids resulting in characteristically different SHOP profiles between the two CTL groups. Similarly, Yersinia-derived and self nonapeptides known to bind HLA-B27 differed in SHOP profiles. To validate the method we have extended SHOP analysis to published TCRB sequence data from additional TCRB-CDR3 from peptide-specific CTL but not in TCRB from HLA-B27-alloreactive CTL or non-HLA-B27-restricted control CTL. We here demonstrate that SHOP may improve TCR-CDR3 sequence analysis by detection of structural constraints which remain cryptic by conventional sequence analysis. Our data suggest that electrostatic properties rather than rigid sequence motifs determine T cell specificities.

HLA-B27-restricted cytotoxic T lymphocyte responses to arthritogenic enterobacteria or self-antigens are dominated by closely related TCRBV gene segments. A study in patients with reactive arthritis

Identification of the T-cell receptors (TCR) used by synovial cytotoxic T lymphocytes (CTL) of patients with reactive arthritis (ReA) may be crucial to better understanding the pathogenetic mechanism underlying the HLA-B27 association of spondylarthropathies. The authors, therefore, sequenced 25 TCRB chains from HLA-B27-restricted CD8+ CTL clones and two clonal lines specific for self- or Yersinia enterocolitica antigen isolated from synovial fluids of 3 HLA-B27+ patients with ReA and PBL of one healthy HLA-B27+ individual. Fourteen non-HLA-B27-restricted CTL served as controls. Both autoreactive and Y. enterocolitica specific HLA-B27-restricted CTL used a highly limited set of VB genes with preferential rearrangement of three closely related VB families (VB 13, 14, 17), suggesting that these families contain a preferred site for contact with the HLA-B27 molecule. In addition, the presence of limited TCRBJ usage, limited heterogeneity in CDR3 sequences and dominant clones from individual donors among these CTL indicate that TCRB chain usage is further restricted by a limited set of peptides bound to the HLA-B27 molecule. Limited TCR usage by SF CTL of ReA patients may lay a basis for therapeutical manipulation of the T-cell response in the spondylarthropathies.

The T cell receptor (TCR) in HLA-B27-restricted T cell responses--an introduction

Recent data indicate that cytotoxic T lymphocytes (CTL) are involved in the pathogenesis of HLA-B27-associated spondylarthropathies. In the absence of clearly defined "arthritogenic" bacterial or self peptides that are presented by HLA-B27 and recognized by such CD8+CTL, one approach has been to investigate the T cell repertoire of lesional cellular infiltrates by determining T cell receptor (TCR) variable (V) gene segment frequencies. Furthermore, the TCR V alpha and V beta chains of HLA-B27-restricted CTL clones, notably the putative peptide-contacting CDR3-regions of these TCRs, have been sequenced. This article will give a short review of the current literature on the topology of the TCR and its hypervariable CDR3 region, TCR repertoire diversity in rheumatic diseases and will concentrate on TCR V alpha and V beta gene usage in HLA-B27-restricted T cell responses.

A patient-derived cytotoxic T-lymphocyte clone and two peptide-dependent monoclonal antibodies recognize HLA-B27-peptide complexes with low stringency for peptide sequences

HLA-B27 molecules expressed on the T2 mutant cell line do not have peptides. Such empty HLA-B27 molecules were not recognized by an HLA-B27-restricted cytotoxic T-lymphocyte (CTL) clone (auto-1) derived from synovial fluid. To test for peptide dependency of the clone, B27-T2 cells were incubated with a panel of 48 different peptides. This lack of stringency was compared with that of a peptide-dependent monoclonal antibody, B27.M2. Positive B27.M2 reactivity resulted when the B27-T2 cells were incubated with two peptides: RRKAMFEDI and RRMGPPVGHR, derived from Chlamydia HSP60 and human ribonucleoprotein, respectively. Because of the limited availability of CTL versus monoclonal antibody, the specificity of B27.M2 was studied in greater detail. The importance of the HLA-B27 heavy chain in antibody recognition of class I-peptide complexes was demonstrated by site-directed mutagenesis. The stringency of the peptide residues was tested by making analogs of each of the nine residues in RRKAMFEDI, creating a panel of 180 analogs. Although stringency was highest for the sixth position, as many as six different amino acids provided positive reactivity. These results indicate that immune recognition of HLA-B27-peptide complexes might have rather low stringency for the peptide sequences. In theory, then, pathogen-derived peptides which induce autoimmunity by generating autoreactive CTL might not share much sequence similarity with the responsible self peptides.

Central vasopressin in experimental aortic stenosis in the rat

OBJECTIVE

In several forms of heart disease characterised by low cardiac output, activated neurohumoral systems including increased vasopressin plasma levels play a key role in the changes in cardiovascular function. The aim of this study was to test the hypothesis that under such conditions the central vasopressin system might also be altered, which could contribute to deranged cardiovascular control.

METHODS

Aortic stenosis was produced in 22 rats by placing a Silver clip (inner diameter 0.6 mm) on the ascending aorta. After 12 weeks, haemodynamic and hormonal measurements were performed, and vasopressin content was determined in 20 microdissected brain areas (micropunch technique). Twenty two sham operated rats served as controls.

RESULTS

Twelve weeks after placing the supravalvular clip, significant aortic stenosis was documented by left ventricular myocardial hypertrophy. Cardiac index was significantly reduced and the peripheral vascular resistance index was increased, while poststenotic aortic pressure was non-significantly decreased. Plasma renin concentration [6.8(SEM 0.9) v 2.1(0.2) ngAI.ml-1.h-1 in controls] and plasma vasopressin [32.9(12.5) v 18.4(6.0) pg.ml-1] were significantly increased, while plasma and urinary noradrenaline remained unaltered. The vasopressin content was significantly altered in eight out of 20 brain areas investigated. Concerning the vasopressin producing hypothalamic nuclei, concentrations were increased in the paraventricular [7494(360) v 4744(237) pg.mg-1 protein, P < 0.05] and suprachiasmatic [3613(170) v 1784(197) pg.mg-1 protein, P < 0.01], but not in the supraoptic nuclei. Rats with aortic stenosis showed significantly raised vasopressin concentrations in the median eminence [25 186(1682) v 37 367(1345) pg.mg-1 protein, P < 0.01], where the hormone is mainly concentrated in the hypothalamo-hypophysial tract. Vasopressin content was significantly decreased in locus coeruleus [49(5) v 89(6) pg.mg-1 protein], which is known to be involved in modulation of sympathetic activity.

CONCLUSIONS

As well as showing increased secretion of vasopressin into the blood with consecutive peripheral antidiuretic and vasoconstrictive effects, these data suggest an alteration in the central vasopressin system in aortic stenosis which might transmit cardiovascular effects by neuromodulation and neuroregulation.

Synovial fluid MHC-unrestricted gamma delta-T lymphocytes contribute to antibacterial and anti-self cytotoxicity in the spondylarthropathies

OBJECTIVE

In reactive arthritis (ReA), synovial fluid-derived bacteria-specific CD4+ and CD8+ T cells have been studied intensively in recent years. We have addressed the question whether gamma delta-TCR+ lymphocytes could contribute to antibacterial or anti-self cytotoxicity in the affected joints of patients, with spondylarthropathies.

METHODS

T cell clones were derived by random cloning from the synovial fluids of one patient with Yersinia-induced ReA, one patient with a Yersinia-induced flare up of pre-existing ankylosing spondylitis, and one patient with ankylosing spondylitis. Eight clones with a CD3+, alpha beta-TCR-, CD4-, CD8- and gamma delta-TCR+ phenotype (all expressing V gamma 9) were tested in a standard 52Cr-release assay using autologous or allogeneic B cell lines, CIR-B27, Daudi cells, and RJ.225 cells.

RESULTS

Four gamma delta-TCR+ clones killed both autologous and allogeneic target cells when infected with live Yersinia or Salmonella and also uninfected Daudi cells expressing GroEL heatshock protein. One clone was specific for Yersinia-infected targets. Three gamma delta-TCR+ clones were cytotoxic when uninfected autologous or allogeneic targets were employed. Polymorphic "classical" MHC class I or class II molecules were not used as restriction elements.

CONCLUSION

We conclude that, upon in vivo contact with bacteria such as Yersinia and Salmonella, synovial gamma delta-T lymphocytes are activated and contribute to antibacterial immunity via specific target cell lysis. Furthermore, anti-self cytolytic gamma delta-T cells could participate in the clearance of stressed and detrimental cells in the arthritic joint or, alternatively, could support the chronicity of autoimmune arthritis.

Analysis of antigens recognized on human melanoma cells by A2-restricted cytolytic T lymphocytes (CTL)

We have pursued our analysis of potential tumor-rejection antigens recognized on human melanoma by autologous cytolytic T lymphocytes (CTL). We reported previously that 3 distinct antigens (A,B,C) were recognized on melanoma cell line SK29-MEL in association with HLA-A2. Selection for melanoma-cell variants resistant to anti-A CTL revealed that antigen A consists of at least 2 determinants (Aa, Ab) which can be lost separately. Genetic linkage between Aa and Ab was suggested by concomitant loss of Aa and Ab in an immunoselected tumor-cell variant. This variant was also resistant to an autologous CTL clone restricted by HLA-B45, indicating that this CTL may also recognize a determinant of antigen A. Of 11 allogeneic HLA-A2 melanoma cell lines that were tested, 5 expressed both Aa and Ab, 1 expressed only Aa, and 1 only Ab. None of them was lysed by anti-B or anti-C CTL clones. A CTL clone derived from another HLA-A2-melanoma patient was found to have exactly the same lytic pattern as the anti-Ab CTL of the first patient. This suggested that it may be possible to elicit an anti-Ab response in many HLA-A2 patients. We conclude that there are at least 2 distinct antigens presented in association with HLA-A2 that are common to many melanomas and therefore constitute promising targets for specific immunotherapy.