Digital amorphous silicon flat-panel detector radiography at different exposure doses versus mammography film: possibility of radiation dose reduction in detecting rheumatologic bone defects

BACKGROUND

Radiographic examinations of the skeleton are the most commonly performed radiologic procedures, even outnumbering examinations of the chest. The imaging systems used in skeletal radiography must meet high standards in terms of contrast and spatial resolution to effectively visualize the high contrast between bone and soft tissue as well as fine bone structures.

PURPOSE

To determine the performance of amorphous silicon flat-panel detector radiography compared to mammography film in detecting rheumatologic bone defects at different exposure doses.

MATERIAL AND METHODS

The study enrolled 44 patients with known or presumed skeletal changes of the hand associated with inflammatory rheumatic diseases. Following a clinically indicated radiographic examination of the peripheral extremities using mammography film, a survey radiograph of one hand was taken in the posteroanterior (PA) view by digital radiography, at the same exposure dose and at a dose reduced to one quarter of the mammography film doses. Four independent radiologists scored the resultant images using the Sharp/van der Heijde and Ratingen scoring methods. The study received University of Cologne Ethics Committee and German Federal Radiation Protection Agency approval.

RESULTS

Compared to mammography film, digital flat-panel detector radiography produced a significantly better image quality at identical uptake doses. A greater number of erosions were detected with the digital flat-panel detector than with mammography film at the same and at reduced doses.

CONCLUSION

Although the spatial resolution of the digital flat-panel system used in this study was poorer than mammography film, this was compensated for by its wider dynamic range and improved contrast resolution, even at the reduced dose.

First clinical trials of a new heteropolymer technology agent in normal healthy volunteers and patients with systemic lupus erythematosus: safety and proof of principle of the antigen-heteropolymer ETI-104

BACKGROUND

The heteropolymer technology was developed to remove pathogens from the circulation.

OBJECTIVES

To evaluate the safety and tolerability of a single administration and to establish proof of principle for ETI-104 in normal healthy volunteers (NHV) and patients with systemic lupus erythematosus (SLE) METHODS: The drug was given intravenously to 11 NHV and six patients with SLE. Over 28 days, vital signs were noted, a haematological and chemical analysis of blood and urine was carried out, and adverse events were recorded. CR1 receptor numbers, the ability of antigen based heteropolymers to bind to red blood cells (RBCs), and the clearance of high avidity and total anti-dsDNA antibodies were measured by Farr assays and FACS analysis.

RESULTS

No safety measure differed significantly from normal in both groups; no drug related serious adverse events occurred. ETI-104 rapidly bound to RBCs in NHV and patients with SLE. Binding of the drug to RBCs of patients with SLE also caused a rapid reduction of circulating anti-dsDNA antibodies in the plasma 15 minutes after administration, with a maximum reduction of 55% (range 43-62). At 28 days statistically significant decreases were maintained in three patients, while in the other three the values had returned to baseline levels.

CONCLUSION

These clinical trials established the safety and the proof of principle of the new immunoconjugate ETI-104. This provides the basis for further development of this technology for numerous indications-for example, therapeutic options for autoimmune diseases or viral and bacterial infections.

[New biological therapeutic options for the treatment of RE: inhibition of costimulatory molecules and blockade of Interleukin-6-interaction]

After approval of TNF and interleukin-1 inhibiting agents for treatment of refractory rheumathoid arthritis, new agents inhibiting interleukin-6 and costimulatory pathways are entering clinical phase I and II trials. Blockade of costimulation by using a CTLA4 immunoglobulin fusion protein (CTLA4Ig), which inhibits the interaction between CD 28 and CD80/86, has been studied in humans and was demonstrated to be well tolerated and efficacious. A monoclonal antibody to the IL-6 receptor (MRA) blocks bioactivity of IL-6 and also showed favorable effects in first clinical trials. Drug safety data on both substances revealed no severe toxicity or increased incidence of severe infections. For the first time combinations of biological substances like CTLA4Ig and etanercept were demonstrated to be effective and showed no evidence for an increased rate of severe infectious complications. Encouraged by data on these two agents there is substancial hope for a broadened therapeutic armentarium of biological agents in refractory rheumatoid arthritis.

Peritoneal dialysis fluids with a physiologic pH based on either lactate or bicarbonate buffer-effects on human mesothelial cells

Conventional lactate (Lac)-buffered peritoneal dialysis (PD) solutions have turned out to be detrimental to human peritoneal cells, especially because of a low pH. In the present study, we focus on potential differences between Lac and bicarbonate (Bic) as a buffer when adjusted to a physiological pH. All test fluids were buffered with either 40 mmol/L of Lac or 34 mmol/L of Bic, sterile filtered, and adjusted to a pH of 7.4. Osmotic agents used were 1.36% glucose (Glu), 3.86% Glu, 1% amino acids (AA), and 7.5% Glu polymer (Glupoly). Human peritoneal mesothelial cells (HPMCs) were isolated from the omentum majus, grown to confluence, and incubated after the second passage for 15 minutes (37 degrees C and 5% carbon dioxide) with the test fluids. Cytotoxicity was controlled by measuring apoptotic and necrotic cells with cytofluorometry. Aerobic cell metabolism (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide [MTT] assay) and intracellular adenosine triphosphate (ATP) concentrations were measured to assess cell viability. Release of interleukin-6 (IL-6) from HPMCs was determined as a parameter of cellular host defense. No significant difference in apoptosis or necrosis rates was found between the solutions adjusted to normal pH. However, in the MTT assay, Bic solutions were superior to corresponding Lac pendants at an identical pH of 7.4 (P < 0.01). Intracellular ATP concentrations reflected a very similar pattern (P < 0.05). Glupoly in combination with Lac showed an impaired pattern with both the MTT and ATP assays. Regarding IL-1beta-stimulated IL-6 release, there was a small, but not significantly better, response for Bic. Differences in manifest cell cytotoxicity reflected by apoptosis and necrosis rates could not be detected comparing PD solutions buffered with Lac or Bic at a physiological pH. However, distinct parameters of cell metabolism were superior with Bic compared with Lac. Especially Glupoly was inferior in combination with Lac as a buffer.

Effect of 1alpha,25(OH)2-vitamin D3 on TNF alpha-mediated apoptosis of human primary osteoblast-like cells in vitro

1alpha,25(OH)2-vitamin D3 is a hormone which potentially stimulates bone cell growth and differentiation. TNFalpha is one possible inductor for apoptosis; apoptosis being an important regulatoring factor for bone modelling and remodelling. We examined the influence of physiological levels (0.1 nM) 1alpha,25(OH)2-vitamin D3 on TNFalpha-mediated apoptosis in human osteoblast-like cells. These human cells were obtained from bone fragments obtained during orthopedic operations on patients without systemic bone disease. Treatment with 1alpha,25(OH)2-vitamin D3 for 8 weeks resulted in a significant reduction (30%) of viable cell number compared to untreated cells. Incubation with TNFalpha (100 ng/ml for 4 hours) only had limited effects on the rate of apoptosis in control cells. After pretreatment with 1alpha,25(OH)2-vitamin D3, induction of apoptosis increased up to 10% in human osteoblast-like cells. In parallel to the induction of apoptosis, 1alpha,25(OH)2-vitamin D3 stimulated osteocalcin and alkaline phosphatase as markers of mature osteoblasts. Our data suggest that 1alpha,25(OH)2-vitamin D3 has a stimulatory effect on TNFalpha-induced apoptosis in human osteoblast-like cells as a result of 1alpha,25(OH)2-vitamin D3-induced cell differentiation.

Involvement of soluble CD95 in Churg-Strauss syndrome

Deficiency of CD95 (Apo-1/Fas)-mediated apoptosis has recently been found in some autoimmune lymphoproliferative disorders due to inherited mutations of the CD95 gene. In this study, impairment of CD95 ligand-mediated killing of lymphocytes and eosinophils in Churg-Strauss Syndrome (CSS), which was a result of variation of CD95 receptor isoform expression, is demonstrated. Compared to those from healthy individuals, peripheral blood lymphocytes from eight CSS patients exhibit a switch from the membrane-bound CD95 receptor expression to its soluble splice variant, which protects from CD95L-mediated apoptosis. In five out of seven CSS patients recurrent oligoclonal T cell expansions were found, all using a Vbeta-gene from the Vbeta21 family associated with similar CDR3 motifs, indicating the predominance of T cell clones of a similar specificity in the CSS patients. In two of them, the effect of immunosuppressive therapy was studied. In both cases aberrant overexpression of the soluble CD95 receptor isoform and deviations from normal TCR Vbeta-gene usage normalized in parallel with the clinical improvement. Furthermore, soluble CD95 was identified as a survival factor for eosinophils rescuing eosinophils from apoptosis in the absence of growth factors in vitro. Given the role of eosinophils as effector cells in CSS, these findings suggest that soluble CD95 may be mechanistically involved in the disease.

Fas-Mediated apoptosis is inhibited by TSH and iodine in moderate concentrations in primary human thyrocytes in vitro

Programmed cell death (apoptosis) can be found in normal thyroid tissue and in various diseases affecting the thyroid gland. The Fas/Fas ligand (FasL) system is involved in the induction of apoptosis in human thyrocytes. Cross-linking the Fas receptor with its own ligand or with an antibody capable of oligomerizing with the receptor induces programmed cell death. We investigated the role of Fas-induced apoptosis in primary human thyrocytes in vitro. Cell cultures of normal human thyrocytes were prepared from specimens obtained during surgery for uninodular goiter. Apoptosis was induced by incubation of the cells with a monoclonal IgM anti-Fas antibody. The presence of apoptosis was determined by FACS analysis of FITC-labelled annexin V binding combined with dye exclusion of propidium iodide. We found a significant rate of Fas-induced apoptosis in normal thyrocytes after activation with a monoclonal anti-Fas antibody. TSH was able to inhibit Fas-mediated apoptosis in a dose-dependent manner. This effect was more pronounced when thyrocytes were incubated in the presence of interferon-gamma. Low concentrations of iodine were able to inhibit apoptosis, while high concentrations of iodine increased the rate of Fas-induced apoptosis. Our results show that Fas-mediated apoptosis is inducible in normal human thyrocytes in vitro and is influenced by TSH and iodine. The Fas/FasL system may play an important role in the regulation of cell number within the thyroid gland, and may be involved in the processes leading to goiter in iodine deficiency.

Detection of cerebral microemboli in APS--introducing a novel investigation method and implications of analogies with carotid artery disease

Patients with antiphospholipid syndrome (APS) are prone to thromboembolism. So far, the only predictive parameters for further complications are their number in patient's history and perhaps the titre of aPL. Derived from clinical investigation of stroke and obvious analogies between cerebrovascular ischemia (CVI) in patients with carotid artery disease (CAD) and patients with APS, a novel non-invasive method is introduced using transcranial Doppler (TCD) long-term monitoring to detect high energy ultrasonic signals (so called 'microemboli') in the cerebral vasculature. In patients with CAD, these microemboli proved to correlate with past and impending symptoms of CVI permitting therapeutic stratification by their detectability. In SLE and APS. this technique enabled identification of very similar signals in cerebral bloodstream of APS patients. Microemboli were highly associated with the history of CVI and the titre of aPL. Detection of microemboli offers new possibilities in risk estimation, therapeutic stratification and in studying pathophysiology of APS.

Prospective randomized trial of two different immunoadsorbers in severe systemic lupus erythematosus

Experiences with extracorporeal therapy in systemic lupus erythematosus have been published over the last 20 years and more. In addition to plasmapheresis, specific adsorption columns have been developed to deplete pathogenic antibodies and immune complexes in the plasma of patients with SLE. We conducted a prospective randomized trial to compare the efficacy of a disposable adsorption column, which contained a specific ligand, phenylalanine (IMPH-350|Pt, Diamed, Köln, Germany) with a regenerable Ig-adsorbing column containing sheep anti-human antibodies (Ig-Therasorb|Pt, Therasorb, München, Germany). Twenty SLE patients inadequately controlled with corticosteroids, anti-malarials, azathioprine or cyclosporine A, had strong evidence of disease in general, or an organ related SLAM score. They were randomized to receive either a perfusion of IMPH-350, or Ig-Therasorb, immunoadsorbed with 2.5 ml of plasma, three times each. The treatment regime was repeated after 4 weeks when the response was limited or non-existent. Response was defined as a reduction in the SLAM score of at least 30%. SLAM scores in the IMPH group decreased from 14.3+/-5.6 to 9.2+/-6.2 after 1 month and to 9.4+/-3.9 after 6 months; corresponding scores in the Ig-Therasorb group were 18.3+/-5. 5 to 11.2+/-7.6, decreasing to 9.2+/-2.9. After 1 month, 8/10 patients in both groups showed a response; after 6 months, 5/10 patients in the IMPH-350 group and 8/10 in the Ig-Therasorb group fulfilled the response criteria. Reduction of dsDNA antibodies directly after treatment was 50.8+/-6.6% in the IMPH-350 group and 61.0+/-8.0% in the IgTherasorb group. Results indicate that immunoadsorption is an additional option in the treatment of severe SLE. Choice of type of immunoadsorber and immunosuppressive treatment has to take into account the severity and chronicity of common disease activity and organ involvement, as well as economic aspects.

High levels of circulating early apoptic peripheral blood mononuclear cells in systemic lupus erythematosus

Increased in vitro apoptosis and altered expression of apoptosis-related molecules have been reported in systemic lupus erythematosus (SLE). It was speculated that autoantigens released from apoptizing cells may contribute to the etiopathogenesis of SLE by both activation of autoreactive lymphocytes and the formation of immune complexes. Conflicting data about the level of cellular apoptosis from animal models for SLE and human SLE indicate different pathomechanisms. In the present study we analysed the count of circulating early apoptotic cells and its correlation with the clinical activity in SLE compared with the amount in primary systemic vasculitis (PSV). The percentage of early apoptotic cells determined by Annexin V-FITC binding cells was significantly increased in peripheral blood of SLE patients compared with normal healthy donors (NHD) and PSV (NHD 5.62%, SLE 13.68%, PSV 8.69%). Analysis of lymphocytes revealed significantly increased counts in the T cell populations (NHD 5.15%, SLE 12.22%, PSV 10.01%), whereas the increase in B cells did not reach significance level (NHD 9.20%, SLE 18.95%, PSV 16.59%). Apoptotic cell count revealed no correlation to SLAM-Score or to immunosuppressive therapy, corticosteroid-dosage or absolute lymphocyte count. The general increase of circulating apoptotic cells may indicate an impaired clearance in SLE patients, independent of clinical activity or therapeutic interventions. Autoantigens from apoptotic cells may contribute to both activation of autoreactive lymphocytes and formation of immune complexes.

Immunoadsorption in systemic connective tissue diseases and primary vasculitis

Immunoadsorption offers some advantages over plasmapheresis; until recently the primary advantage has been avoidance of substitution fluids. In collagen vascular disorders, immunoadsorption is performed for the same indications as plasma exchange; most often adsorbers with binding capacities for IgG and circulating immune complexes are used. Tested ligands are protein A, anti-IgG antibodies, Clq, phenylalanine, and tryptophan. Human IgG was utilized to adsorb rheumatoid factor and dextran sulfate, DNA, or specific anti-idiotypes for anti-DNA antibodies in systemic lupus erythematous (SLE). Most applications have used immunoadsorbent columns in pretransplantation treatment of patients with high panel reactivity and in patients with idiopathic thrombocytopenic purpura (ITP). For these indications, as for systemic connective tissue diseases, randomized trials have yet to be conducted. SLE controlled trials have been completed for IMPH-350 and Ig-Therasorb. Results indicated excellent biocompatibility and good clinical responses. Using protein A in primary systemic vasculitis, histologically proven inactivation of renal involvement was demonstrated, but the patients were also treated with immunosuppressive drugs. Randomized controlled trials are mandatory to provide continued support to the therapeutical opportunities offered only by immunoadsorption.