Intratumoral heterogeneity after targeted therapy in murine cancer models with differing degrees of malignancy

INTRODUCTION

Conventional morphologic and volumetric assessment of treatment response is not suitable for adequately assessing responses to targeted cancer therapy. The aim of this study was to evaluate changes in tumor composition after targeted therapy in murine models of breast cancer with differing degrees of malignancy via non-invasive magnetic resonance imaging (MRI).

MATERIALS AND METHODS

Mice bearing highly malignant 4T1 tumors or low malignant 67NR tumors were treated with either a combination of two immune checkpoint inhibitors (ICI, anti-PD1 and anti-CTLA-4) or the multi-tyrosine kinase inhibitor sorafenib, following experiments with macrophage-depleting clodronate-loaded liposomes and vessel-stabilizing angiopoietin-1. Mice were imaged on a 9.4 T small animal MRI system with a multiparametric (mp) protocol, comprising T1 and T2 mapping and diffusion-weighted imaging. Tumors were analyzed ex vivo with histology.

RESULTS AND DISCUSSIONS

All treatments led to an increase in non-viable areas, but therapy-induced intratumoral changes differed between the two tumor models and the different targeted treatments. While ICI treatment led to intratumoral hemorrhage, sorafenib treatment mainly induced intratumoral necrosis. Treated 4T1 tumors showed increasing and extensive areas of necrosis, in comparison to 67NR tumors with only small, but also increasing, necrotic areas. After either of the applied treatments, intratumoral heterogeneity, was increased in both tumor models, and confirmed ex vivo by histology. Apparent diffusion coefficient with subsequent histogram analysis proved to be the most sensitive MRI sequence. In conclusion, mp MRI enables to assess dedicated therapy-related intratumoral changes and may serve as a biomarker for treatment response assessment.

Feasibility and optimal choice of stimulation parameters for supramaximal stimulation of motor evoked potentials

PURPOSE

The aim was to investigate the feasibility and optimal stimulation parameters for supramaximal stimulation of muscle recorded transcranial electrical stimulation motor evoked potentials (mTc-MEP).

METHODS

Forty-seven consecutive patients that underwent scoliosis surgery were included. First, the feasibility of supramaximal stimulation was assessed for two settings (setting 1: pulse duration 0.075ms, interstimulus interval (ISI) 1.5ms; setting 2: pulse duration 0.300ms, ISI 3ms). Thereafter, three mTc-MEP parameters were considered for both settings; (1) elicitability, (2) amplitude, and (3) if supramaximal stimulation was achieved with ≥ 20 V below maximum output. Finally, ISIs (1ms-4ms) were optimized for setting 1.

RESULTS

Nine patients (19.15%) were excluded. Of the remaining patients, supramaximal stimulation was achieved in all patients for setting 1, and in 26 (68.42%) for setting 2. In one patient, mTc-MEPs were elicitable in more muscles for setting (1) Amplitudes were not significantly different. Stimulation voltage could be increased ≥ 20 V in all 38 patients for setting 1 and in 10 (38.46%) for setting (2) Optimal ISI's differed widely.

CONCLUSION

We recommend using setting 1 when monitoring mTc-MEPs with supramaximal stimulation, after which an individualized ISI optimization can be performed. Moreover, when using supramaximal stimulation, short ISI's (i.e. 1ms or 1.5ms) can be the optimal ISI for obtaining the highest mTc-MEP amplitude.

The risk of delayed spinal cord injury in pediatric spinal deformity surgery

Delayed spinal cord injury (SCI) hours or days after surgery, with uneventful monitoring and initial normal postoperative neurological examination, is a rare complication. Based on anecdotal evidence, the risk of delayed spinal cord injury might be higher than previously assumed. Therefore the aim of this study was to determine the risk of delayed SCI after pediatric spinal deformity surgery between 2013-2019 in the Netherlands. The total number of pediatric spinal deformity surgeries performed for scoliosis or kyphosis between 2013-2019 was obtained from the Dutch National Registration of Hospital Care. All eleven Dutch hospitals that perform pediatric spinal deformity surgery were contacted for occurrence of delayed SCI. From the identified patients with delayed SCI, the following data were collected: patient characteristics, details about the SCI, the surgical procedure, management and degree of improvement.2884 pediatric deformity surgeries were identified between 2013-2019. Seven patients (0.24%) with delayed SCI were reported: 3 idiopathic, 2 neuromuscular (including 1 kypho-scoliosis) and 2 syndromic scoliosis. The risk of delayed SCI after pediatric deformity surgery was 1:595 in idiopathic scoliosis, 1:214 in syndromic scoliosis, 1:201 in neuromuscular scoliosis. All seven patients had a documented normal neurological examination in the first postoperative period; neurological deficits were first diagnosed at a median 16h (range 2.5-40) after surgery. The risk of delayed SCI after pediatric deformity surgery is higher than previously reported, especially in patients with non-idiopathic scoliosis. Regular postoperative testing for late neurologic deficit should be performed for timely diagnosis and management of this devastating complication.

Assessment of spine length in scoliosis patients using EOS imaging: a validity and reliability study

PURPOSE

Knowledge about spinal length and subsequently growth of each individual patient with adolescent idiopathic scoliosis (AIS) helps with accurate timing of both conservative and surgical treatment. Radiographs taken by a biplanar low-dose X-ray device (EOS) have no divergence in the vertical plane and can provide three-dimensional (3D) measurements. Therefore, this study investigated the criterion validity and reliability of EOS spinal length measurements in AIS patients.

METHODS

Prior to routine EOS radiograph, a radiographic calibrated metal beads chain (MBC) was attached on the back of 120 patients with AIS to calibrate the images. Spinal lengths were measured from vertebra to vertebra on EOS anteroposterior (AP), lateral view and on the combined 3D EOS view (EOS 3D). These measurements were compared with MBC length measurements. Secondly, intra- and interobserver reliability of length measurements on EOS-images were determined.

RESULTS

50 patients with accurately positioned MBC were included for analysis. The correlations between EOS and MBC were highest for the 3D length measurements. Compared to EOS 3D measurements, the total spinal length was systematically measured 4.3% (mean difference = 1.97 ± 1.12 cm) and 1.9% (mean difference = 0.86 ± 0.63 cm) smaller on individual EOS two-dimensional (2D) AP and lateral view images, respectively. Both intra- and interobserver reliability were excellent for all length measurements on EOS-images.

CONCLUSION

The results of this study indicate a good validity and reliability for spinal length measurements on EOS radiographs in AIS patients. EOS 3D length measure method is preferred above spinal length measurements on individual EOS AP or lateral view images.

AB0355 THE VALUE OF PLATELET-TO-LYMPHOCYTE AND NEUTROPHIL-TO-LYMPHOCYTE RATIOS AS INFLAMMATORY MARKERS IN BIOPSY-PROVEN GIANT CELL ARTERITIS

Background:

Platelet-to-lymphocyte ratio (PLR) and neutrophil-to-lymphocyte ratio (NLR) have been shown to correlate with disease activity in various rheumatic diseases. High PLR and elevated platelet count are potentially useful in diagnosing some systemic vasculitides, eg. giant cell arteritis (GCA)1 and has been suggested predictive for diagnosing GCA, even in the absence of characteristic temporal artery involvement2.

Objectives:

To evaluate the role of PLR and NLR as inflammatory markers in the diagnosis of GCA in patients referred to temporal artery biopsy (TAB).

Methods:

During 10 months, all patients referred to TAB at the Department of Ophthalmology (Rigshospitalet, Copenhagen, Denmark) in suspected GCA were included. Immediately prior to TAB, ultrasound of bilateral temporal arteries was performed at the Center for Rheumatology and Spine Disease (Rigshospitalet, Copenhagen, Denmark) by rheumatologists experienced in vascular ultrasound. Ultrasound signs of GCA were a positive Halo sign or compression sign. Patients had C-reactive protein (CRP), erythrocyte sedimentation ratio (ESR), platelets, white blood cells with differential counts, hemoglobin and platelets measured. Final clinical diagnosis, based on rheumatological expert opinion, and fulfilment of ACR1990 classification criteria for temporal arteritis at six months was noted, with clinical diagnosis being the reference standard.

Results:

106 patients were included and had a TAB evaluated. Forty-five (42%) had a clinical diagnosis of GCA at 6 months of which 28 (62%) also were TAB positive. US was performed in 74 (70%), of these 20 (67%) of the GCA patients had a positive ultrasound for GCA (termed US GCA patients). There was no significant difference in mean age or gender distribution between GCA and non-GCA patients. ESR, CRP and platelets were significantly higher in GCA than non-GCA patients (p<0.001). PLR was significantly higher in GCA than non-GCA patients (p<0.007), while NLR was not (p=0.076). For US GCA patients vs. US non-GCA patients, platelets were significantly higher in the US GCA group (p=0.025). Both PLR and NLR were significantly higher in the US GCA group compared to the US non-GCA group (p= 0.003 and p=0.007, respectively).

Conclusion:

In this cohort of patients, suspected of GCA and referred to TAB, PLR but not NLR was significantly higher in GCA patients than in non-GCA patients. In patients with US findings of GCA, both PLR and NLR were significantly higher in GCA compared to non-GCA. An elevated PLR could be considered an additional feature in diagnosing GCA.

References:

[1]El-Dairi MA et al.: J Neuroophthalmol 2015;35:246-53

[2]Bornstein G et al.: Clin Rheumatol 2018;37:2819-2

GCA (n=45)Non-GCA (n=61)P-valueAge (years)73.6 (7.5)72.6 (10.4)0.575Females, n (%)34 (76)38 (62)0.148Fulfilling ACR1990 criteria, n (%)36 (80)16 (26)<0.001TAB positive for GCA, n (%)28 (62)0 (0)<0.001Ultrasound positive for GCA*, n (%)20 (67)9 (20)<0.001Sedimentation rate (mm/hr)58 (30)33 (31)<0.001Haemoglobin (mmol/L)7.68 (0.92)7.96 (1.05)0.154CRP (mg/L), median (IQR)38 (15-92)8 (2-40)<0.001White blood cells (109/L)9.54 (3.18)8.99 (3.63)0.407Lymphocytes (109/L)1.72 (0.78)1.87 (0.93)0.367Monocytes (109/L)0.71 (0.37)0.77 (0.41)0.441Neutrophils (109/L)6.85 (2.94)6.01 (3.02)0.157Basophils (109/L)0.05 (0.04)0.05 (0.05)0.464Eosinophils (109/L)0.15 (0.14)0.18 (0.21)0.410Platelets (109/L)400 (154)289 (111)<0.001Neutrophil-to-lymphocyte ratio4.91 (3.22)3.87 (2.52)0.076Platelet-to-lymphocyte ratio287 (189)193 (147)0.007

Values are mean and standard deviation unless noted

Comparison between groups by independent samples t-test (continuous variables), χ2-test (categorical variables) and Mann-Whitney for CRP (not normal distributed continuous variable)

ACR=American College of Rheumatology; CRP=C-reactive protein; GCA=giant cell arteritis; IQR=interquartile range; n=number; SD=standard deviation; TAB=temporal artery biopsy

*Ultrasound not done in 32 patients (15 with GCA and 17 without)

Disclosure of Interests:

None declared

Assessment of pedicle size in patients with scoliosis using EOS 2D imaging: a validity and reliability study

PURPOSE

Free-hand pedicle screw insertion methods are widely used for screw insertion during scoliosis surgery. Preoperative knowledge about the pedicle size helps to maximize screw containment and minimize the risk of pedicle breach. Radiographs taken by a biplanar low-dose X-ray device (EOS) have no divergence in the vertical plane. The criterion validity and reliability of preoperative EOS images for pedicle size measurements in patients with idiopathic scoliosis (IS) was investigated in this study.

METHODS

Sixteen patients who underwent surgical treatment for IS were prospectively included. Intra- and extracortical pedicle height and width measurements on EOS images were compared with reconstructed intra-operative 3D images of the isthmus of included pedicles. Secondly, intra- and interobserver reliability of pedicle size measurements on EOS images was determined.

RESULTS

The total number of analyzed pedicles was 203. The correlation between the EOS and 3D scan measurements was very strong for the intra- and extracortical pedicle height and strong for the intra- and extracortical pedicle width. There are, however, significant, but likely clinically irrelevant differences (mean absolute differences < 0.43 mm) between the two measure methods for all four measurements except for extracortical pedicle height. For pedicles classified as Nash-Moe 0, no significant differences in intra- and extracortical pedicle width were observed. Both intra- and interobserver reliability was excellent for all pedicle size measurements on EOS images.

CONCLUSION

The results of this study indicate a good validity and reliability for pedicle size measurements on EOS radiographs. Therefore, EOS radiographs may be used for a preoperative estimation of pedicle size and subsequent screw diameter in patients with IS.

The influence of depth of anesthesia and blood pressure on muscle recorded motor evoked potentials in spinal surgery. A prospective observational study protocol

For high-risk spinal surgeries, intraoperative neurophysiological monitoring (IONM) is used to detect and prevent intraoperative neurological injury. The motor tracts are monitored by recording and analyzing muscle transcranial electrical stimulation motor evoked potentials (mTc-MEPs). A mTc-MEP amplitude decrease of 50–80% is the most common warning criterion for possible neurological injury. However, these warning criteria often result in false positive warnings. False positives may be caused by inadequate depth of anesthesia and blood pressure on mTc-MEP amplitudes. The aim of this paper is to validate the study protocol in which the goal is to investigate the effects of depth of anesthesia (part 1) and blood pressure (part 2) on mTc-MEPs. Per part, 25 patients will be included. In order to investigate the effects of depth of anesthesia, a processed electroencephalogram (pEEG) monitor will be used. At pEEG values of 30, 40 and 50, mTc-MEP measurements will be performed. To examine the effect of blood pressure on mTc-MEPs the mean arterial pressure will be elevated from 60 to 100 mmHg during which mTc-MEP measurements will be performed. We hypothesize that by understanding the effects of depth of anesthesia and blood pressure on mTc-MEPs, the mTc-MEP monitoring can be interpreted more reliably. This may contribute to fewer false positive warnings. By performing this study after induction and prior to incision, this protocol provides a unique opportunity to study the effects of depths of anesthesia and blood pressure on mTc-MEPs alone with as little confounders as possible.

Trial registration number NL7772.

S. aureus endocarditis: Clinical aspects and experimental approaches

Infective endocarditis (IE) is a life-threatening disease, caused by septic vegetations and inflammatory foci on the surface of the endothelium and the valves. Due to its complex and often indecisive presentation the mortality rate is still about 30%. Most frequently bacterial microorganisms entering the bloodstream are the underlying origin of the intracardiac infection. While the disease was primarily restricted to younger patients suffering from rheumatic heart streptococci infections, new at risk categories for Staphylococcus (S.) aureus infections arose over the last years. Rising patient age, increasing drug resistance, intensive treatment conditions such as renal hemodialysis, immunosuppression and long term indwelling central venous catheters but also the application of modern cardiac device implants and valve prosthesis have led to emerging incidences of S. aureus IE in health care settings and community. The aetiologic change has impact on the pathophysiology of IE, the clinical presentation and the overall patient management. Despite intensive research on appropriate in vitro and in vivo models of IE and gained knowledge about the fundamental mechanisms in the formation of bacterial vegetations and extracardiac complications, improved understanding of relevant bacterial virulence factors and triggered host immune responses is required to help developing novel antipathogenic treatment strategies and pathogen specific diagnostic markers. In this review, we summarize and discuss the two main areas affected by the changing patient demographics and provide first, recent knowledge about the pathogenic strategies of S. aureus in the induction of IE, including available experimental models of IE used to study host-pathogen interactions and diagnostic and therapeutic targets. In a second focus we present diagnostic (imaging) regimens for patients with S. aureus IE according to current guidelines as well as treatment strategies and surgical recommendations.

Polaronic metal state at the LaAlO3/SrTiO3 interface

Interplay of spin, charge, orbital and lattice degrees of freedom in oxide heterostructures results in a plethora of fascinating properties, which can be exploited in new generations of electronic devices with enhanced functionalities. The paradigm example is the interface between the two band insulators LaAlO3 and SrTiO3 that hosts a two-dimensional electron system. Apart from the mobile charge carriers, this system exhibits a range of intriguing properties such as field effect, superconductivity and ferromagnetism, whose fundamental origins are still debated. Here we use soft-X-ray angle-resolved photoelectron spectroscopy to penetrate through the LaAlO3 overlayer and access charge carriers at the buried interface. The experimental spectral function directly identifies the interface charge carriers as large polarons, emerging from coupling of charge and lattice degrees of freedom, and involving two phonons of different energy and thermal activity. This phenomenon fundamentally limits the carrier mobility and explains its puzzling drop at high temperatures.

[Sub-threshold prostate-specific antigen levels after resection of metachronous pulmonary metastases]

Radical prostatectomy is a curative therapy for prostate cancer with a lifetime follow-up because there is a high risk of recurrence, especially in the first years of follow-up. In our case disseminated metachronous pulmonary metastases were detected by imaging 4 years after prostatectomy because of elevated levels of serum prostate-specific antigen (PSA). After complete resection of the thoracic metastases the PSA levels have remained below the detection threshold with a recurrence-free survival of 24 months. This case demonstrates that the resection of pulmonary metastases may also be useful for specific individual patients with prostate cancer.

Many-body Green's function GW and Bethe-Salpeter study of the optical excitations in a paradigmatic model dipeptide

We study within the many-body Green's function GW and Bethe-Salpeter formalisms the excitation energies of a paradigmatic model dipeptide, focusing on the four lowest-lying local and charge-transfer excitations. Our GW calculations are performed at the self-consistent level, updating first the quasiparticle energies, and further the single-particle wavefunctions within the static Coulomb-hole plus screened-exchange approximation to the GW self-energy operator. Important level crossings, as compared to the starting Kohn-Sham LDA spectrum, are identified. Our final Bethe-Salpeter singlet excitation energies are found to agree, within 0.07 eV, with CASPT2 reference data, except for one charge-transfer state where the discrepancy can be as large as 0.5 eV. Our results agree best with LC-BLYP and CAM-B3LYP calculations with enhanced long-range exchange, with a 0.1 eV mean absolute error. This has been achieved employing a parameter-free formalism applicable to metallic or insulating extended or finite systems.

Excited states properties of organic molecules: from density functional theory to the GW and Bethe-Salpeter Green's function formalisms

Many-body Green's function perturbation theories, such as the GW and Bethe-Salpeter formalisms, are starting to be routinely applied to study charged and neutral electronic excitations in molecular organic systems relevant to applications in photovoltaics, photochemistry or biology. In parallel, density functional theory and its time-dependent extensions significantly progressed along the line of range-separated hybrid functionals within the generalized Kohn-Sham formalism designed to provide correct excitation energies. We give an overview and compare these approaches with examples drawn from the study of gas phase organic systems such as fullerenes, porphyrins, bacteriochlorophylls or nucleobases molecules. The perspectives and challenges that many-body perturbation theory is facing, such as the role of self-consistency, the calculation of forces and potential energy surfaces in the excited states, or the development of embedding techniques specific to the GW and Bethe-Salpeter equation formalisms, are outlined.

Treatment options for patients with mobile left ventricular thrombus and ventricular dysfunction: a case series

INTRODUCTION

Little is known about the optimal management of large, mobile, pedunculated left ventricular clots. The management is particularly challenging in patients with advanced heart failure considered for left ventricular assist device implantation, because the clot may cause pump thrombosis.

METHODS

We retrospectively reviewed the records of patients with left ventricular thrombi identified by echocardiography, and found three cases with large protruding mobile clots.

RESULTS

In this paper, we are presenting three challenging cases where the clots were successfully treated surgically. In two cases, the removal of clot was performed simultaneously with the implantation of ventricular assist devices. In the third case, the patient underwent only thrombectomy. Overall, the early outcomes were good in all three patients, but one subsequently died from unrelated causes.

CONCLUSIONS

These clinical cases give evidence for surgical treatment of large mobile clots without systemic embolism, even if ventricular assist device is implanted during the same operation.

Molecular fingerprints in the electronic properties of crystalline organic semiconductors: from experiment to theory

By comparing photoemission spectroscopy with a nonperturbative dynamical mean field theory extension to many-body ab initio calculations, we show in the prominent case of pentacene crystals that an excellent agreement with experiment for the bandwidth, dispersion, and lifetime of the hole carrier bands can be achieved in organic semiconductors, provided that one properly accounts for the coupling to molecular vibrational modes and the presence of disorder. Our findings rationalize the growing experimental evidence that even the best band structure theories based on a many-body treatment of electronic interactions cannot reproduce the experimental photoemission data in this important class of materials.

The human epidermal growth factor receptor (EGFR) gene in European patients with advanced colorectal cancer harbors infrequent mutations in its tyrosine kinase domain

BACKGROUND

The epidermal growth factor receptor (EGFR), a member of the ErbB family of receptors, is a transmembrane tyrosine kinase (TK) activated by the binding of extracellular ligands of the EGF-family and involved in triggering the MAPK signaling pathway, which leads to cell proliferation. Mutations in the EGFR tyrosine kinase domain are frequent in non-small-cell lung cancer (NSCLC). However, to date, only very few, mainly non-European, studies have reported rare EGFR mutations in colorectal cancer (CRC).

METHODS

We screened 236 clinical tumor samples from European patients with advanced CRC by direct DNA sequencing to detect potential, as yet unknown mutations, in the EGFR gene exons 18 to 21, mainly covering the EGFR TK catalytic domain.

RESULTS

EGFR sequences showed somatic missense mutations in exons 18 and 20 at a frequency of 2.1% and 0.4% respectively. Somatic SNPs were also found in exons 20 and 21 at a frequency of about 3.1% and 0.4% respectively. Of these mutations, four have not yet been described elsewhere.

CONCLUSIONS

These mutation frequencies are higher than in a similarly sized population characterized by Barber and colleagues, but still too low to account for a major role played by the EGFR gene in CRC.

Overexpression of Dicer predicts poor survival in colorectal cancer

AIMS

The RNASE III endonuclease Dicer is one of the key enzymes of microRNA biogenesis. The influence of Dicer-expression in tumour cells on the prognosis of patients with several cancers has been studied with controversial results among different cancer types. To date no one has examined the effect of this biomarker on survival in colorectal carcinoma. Thus, we aimed to study the influence of Dicer expression on survival in colorectal cancer.

METHODS

We performed immunohistochemical analyses on formalin-fixed paraffin embedded (FFPE) cancer tissue with an antibody against the Dicer protein. Tumour material from 237 cases was available from patients with colorectal adeonocarcinomas with moderate differentiation (G2) and without evidence of lymph-node (N0) or distant metastasis (M0). Sixty-four cases were in T2 and 173 in T3 stages. A tissue microarray (TMA) was constructed with each tumour in triplicate. Each tumour was assigned to a scoring scale of 0-3, depending on the cytoplasmatic expression of Dicer. A Kaplan-Maier analysis was performed and the log-rank test was used for significance levels by using SPSS v.17 software.

RESULTS

The expression of Dicer in colorectal carcinoma shows a strong association with poor survival (cancer specific survival=CSS, p<0,001) as well as with reduced progression free survival (PFS, p<0,001). In the group with no Dicer staining there was no recorded relapse (0/15) compared with 10/18 relapses in the group with the strongest staining of Dicer.

CONCLUSIONS

Strong expression of the central microRNA biosynthesis enzyme Dicer predicts poor prognosis in patients with colorectal cancer. This is in line with investigations on prostate cancer. Contradictory, in breast, lung and ovary cancer Dicer has been shown to be a marker of good prognosis. Further studies on the cellular functions of Dicer need to address these issues.

426 TRANSGENIC PIGS EXPRESSING HIGH LEVELS OF HUMAN THROMBOMODULIN ON VASCULAR ENDOTHELIUM

The development of a1,3-galactosyltransferase deficient pigs along with overexpression of complement regulatory proteins was an important step to overcome hyperacute rejection of pig organs transplanted into primates. However, the lack of galactose-α1,3-galactose (αGal) epitopes does not protect against subsequent rejection mechanisms, such as acute vascular rejection, which plays a crucial role to achieve prolonged graft survival in pig-to-human xenotransplantation. Acute vascular rejection involves incompatibilities between human blood and porcine endothelial cells, leading to coagulation disorders. Indeed, thrombotic microangiopathy is one of the key characteristics of rejected pig-to-primate grafts from aGal-deficient donor animals. One of the strategies to overcome this coagulation problem by genetic modification of donor pigs is expression of human thrombomodulin (TM) on the porcine endothelium. Although porcine TM is able to bind circulating human thrombin, the resulting heterodimer is unable to cleave human protein C, which promotes the coagulation cascade. We addressed this problem by the development of a vector placing the single-exon open reading frame of human TM under the control of a 6-kb promoter fragment obtained from the porcine TM gene. In addition, we replaced the 3′-untranslated region (UTR) by a polyadenylation box from the bovine growth hormone gene to avoid interferon-y-dependent destabilization of thrombomodulin transcripts. This vector was linked to a floxed neomycin cassette and transfected into porcine fetal fibroblasts. Positive cell clones were selected with G418, mixed, and then used for nuclear transfer. Donor fibroblasts were electrofused with enucleated oocytes resulting in 358 reconstructed embryos (91.1% fusion rate). One or two days later, 294 embryos were transferred to 3 synchronized gilts. In total, 8 cloned transgenic piglets with 1 or 2 independent integration sites of the transgene were born. Heart, kidney, lung, and liver of 5 founder animals were analyzed by immunohistochemistry They were found to express thrombomodulin strongly and strictly limited to the vascular endothelium of at least heart and kidney. The staining intensity was estimated qualitatively, by grading from weak to strong immunoreactivity (brown color, using DAB as chromogen). Cells from founder pigs expressing TM strongly have been used for recloning. The effect of human TM to normalize blood coagulation will be tested in experiments involving ex vivo perfusion of transgenic hearts and kidneys with human blood. Supported by the Deutsche Forschungsgemeinschaft (FOR 535).

In vivo high-resolution MR imaging of neuropathologic changes in the injured rat spinal cord

BACKGROUND AND PURPOSE

MR imaging is the most comprehensive noninvasive means to assess structural changes in injured central nervous system (CNS) tissue in humans over time. The few published in vivo MR imaging studies of spinal cord injury in rodent models by using field strengths < or = 7T suffer from low spatial resolution, flow, and motion artifacts. The aim of this study was to assess the capacity of a 17.6T imaging system to detect pathologic changes occurring in a rat spinal cord contusion injury model ex vivo and in vivo.

METHODS

Seven adult female Fischer 344 rats received contusion injuries at thoracic level T10, which caused severe and reproducible lesions of the injured spinal cord parenchyma. Two to 58 days postinjury, high-resolution MR imaging was performed ex vivo (2) or in vivo in anesthetized rats (5 spinal cord injured + one intact control animal) by using 2D multisection spin- and gradient-echo imaging sequences, respectively, combined with electrocardiogram triggering and respiratory gating.

RESULTS

The acquired images provided excellent resolution and gray/white matter differentiation without significant artifacts. Signal intensity changes, which were detected with ex vivo and in vivo MR imaging following spinal cord injury, could be correlated with histologically defined structural changes such as edema, fibroglial scar, and hemorrhage.

CONCLUSIONS

These results demonstrate that MR imaging at 17.6T allows high-resolution structural analysis of spinal cord pathology after injury.

Differential expression patterns of recombination-activating genes in individual mature B cells in juvenile idiopathic arthritis

BACKGROUND

Re-expression of the recombination-activating genes (RAG) in peripheral B cells may be relevant in the development of autoreactive antibodies in autoimmune diseases. The presence of antinuclear antibodies (ANA) as a hallmark of oligoarticular juvenile idiopathic arthritis (o-JIA, early-onset type) indicates a breakdown in immunological tolerance.

AIM

To examine the expression of RAG genes in peripheral blood mature B lymphocytes in patients with o-JIA.

METHODS

777 memory B cells from peripheral blood, CD19+ CD27+ CD5+ or CD19+ CD27+ CD5-, isolated from three ANA+ children with o-JIA and three healthy age-matched children, were examined for the expression of RAG1 and RAG2 mRNA. mRNA transcripts of activation-induced cytidine deaminase and immunoglobulin G were searched to further determine their developmental stage.

RESULTS

mRNA was present for any of the two RAG genes in the B cells of children with JIA and controls. However, the predominance of RAG1 or RAG2 was different. A significantly decreased frequency of RAG2-expressing memory B cells in both CD5+ and CD5- populations was noted in children with JIA (p<0.001), whereas the number of RAG1-expressing B cells was slightly increased. The coordinate expression of both the RAG genes was a rare event, similar in the CD5+ populations (1% in controls, 2% in children with JIA), but different among the CD5- compartments (5% v 0%; p<0.01).

CONCLUSION

These results argue for a reduced coordinate RAG expression in the peripheral CD5- memory B cells of patients with o-JIA. Thus, it was hypothesised that impaired receptor revision contributes to autoimmune pathogenesis in JIA.

The effect of the antimicrobial peptide, Dhvar-5, on gentamicin release from a polymethyl methacrylate bone cement

The objective of this study was to investigate the release mechanism and kinetics of the antimicrobial peptide, Dhvar-5, both alone and in combination with gentamicin, from a standard commercial polymethyl methacrylate (PMMA) bone cement. Different amounts of Dhvar-5 were mixed with the bone cement powders of Osteopal and the gentamicin-containing Osteopal G bone cement and their release kinetics from the polymerized cement were investigated. Additionally, the internal structure of the bone cements were analysed by scanning electron microscopy (SEM) of the fracture surfaces. Secondly, porosity was investigated with the mercury intrusion method and related to the observed release profiles. In order to obtain an insight into the mechanical characteristics of the bone cement mixtures, the compressive strength of Osteopal and Osteopal G with Dhvar-5 was also investigated. The total Dhvar-5 release reached 96% in the 100 mg Dhvar-5/g Osteopal cement, whereas total gentamicin release from Osteopal G reached only 18%. Total gentamicin release increased significantly to 67% with the addition of 50mg Dhvar-5/g, but the Dhvar-5 release was not influenced. SEM showed an increase of dissolved gentamicin crystals with the addition of Dhvar-5. The mercury intrusion results suggested an increase of small pores (< 0.1 microm) with the addition of Dhvar-5. Compressive strength of Osteopal was reduced by the addition of Dhvar-5 and gentamicin, but still remained above the limit prescribed by the ISO standard for clinical bone cements. We therefore conclude that the antimicrobial peptide, Dhvar-5, was released in high amounts from PMMA bone cement. When used together with gentamicin sulphate, Dhvar-5 made the gentamicin crystals accessible for the release medium presumably through increased micro-porosity (< 0.1 microm) resulting in a fourfold increase of gentamicin release.

Analysis of RAG expression by peripheral blood CD5+ and CD5- B cells of patients with childhood systemic lupus erythematosus

BACKGROUND

The assembly of immunoglobulin genes during B cell development in the bone marrow is dependent on the expression of recombination activating genes (RAG) 1 and 2. Recently, RAG expression in peripheral blood IgD+ B cells outside the bone marrow has been demonstrated and is associated with the development of autoimmune diseases.

OBJECTIVE

To investigate RAG expression in the CD5+ or CD5- IgD+ B cell compartment in childhood systemic lupus erythematosus (SLE).

METHODS

Using a combination of flow cytometric cell sorting and reverse transcriptase polymerase chain reaction analysis of cDNA libraries generated from individual cells, the expression of RAG, VpreB, and CD154 mRNA by individual peripheral blood B cells of three paediatric SLE patients was examined in detail.

RESULTS

While only one patient had a significantly increased frequency of RAG+ B cells in the CD5- B cell population, all patients showed higher frequencies of RAG+ B cells in the CD5+IgD+ B cell population. The frequency of RAG+ IgD+CD5+/- B cells was reduced during intravenous cyclophosphamide treatment. In healthy age matched children, RAG expressing IgD+ B cells were hardly detectable. Coexpression of RAG and VpreB or CD154 mRNA could only be found in SLE B cells.

CONCLUSIONS

RAG expression in peripheral blood B cells of SLE patients is particularly increased in the IgD+CD5+ B cell population. CD5+ and CD5- B cells in SLE have the potential to undergo receptor revision leading to the generation of high affinity pathogenic autoantibodies.

Zinc in pharmacological doses suppresses allogeneic reaction without affecting the antigenic response

Zinc is an essential trace element for the immune system. Previously it was shown that zinc inhibits alloreactivity. In our present in vitro experiments, it is shown that zinc maintains the antigenic potency of the host while blocking the allogeneic response. These results were observed in experiments using tetanus toxoid as a well-established recall antigen and the mixed lymphocyte culture as an in vitro model for allogeneic reaction. To prove the in vivo relevance, an ex vivo experimental setup was established. This involved participants taking zinc orally for 1 week. Here it is shown that in vivo zinc application induced the same effect of blocking the mixed lymphocyte culture without influencing tetanus toxoid stimulation. So far, no clinical application studies have been performed, but the observed selective suppression of allogeneic reaction by zinc is the first step towards a new generation of immunosuppressants.

Differential expression of matrix metalloproteinases and cyclooxygenases in synovial cells exposed to Borrelia burgdorferi

OBJECTIVE AND DESIGN

Lyme arthritis is characterized by strong inflammatory reactions probably due to the presence of Borrelia burgdorferi in the joint. It has been suggested that Borrelia adopts different molecular mechanisms that either can amplify the host's inflammatory response or can suppress it. In the present study we analyzed the induction of matrix metalloproteinases (MMPs) and cyclooxygenases (COXs) in human synoviocytes exposed to different B. burgdorferi sensu stricto isolates (Geho and B31).

MATERIALS AND METHODS

Synoviocytes were exposed in vitro for 12 h up to 5 days. Semiquantitative reverse transcription polymerase chain reaction was used to assess the mRNA expression of MMP-1 to 13, COX-1 and COX-2. Prostaglandin E2 (PGE2) production was assessed by ELISA.

RESULTS

MMP-1 was unchanged in synovial cells exposed to strain Geho, whereas it was downregulated by strain B31. MMP-13 was downregulated by both strains. COX-2 was upregulated by strain B31, which resulted in increased PGE2 concentration in the supernatant. In contrast, COX-1 was slightly upregulated and COX-2 tended to be downregulated by Geho resulting in a decreased PGE2 concentration.

CONCLUSIONS

The differential expression of MMPs and COXs suggests that different B. burgdorferi strains influence different molecular mechanisms leading to chronic inflammation. This might be reflected in the clinical variability among Lyme arthritis patients.

23Na microscopy of the mouse heart in vivo using density-weighted chemical shift imaging

The mouse has become an important animal model for human cardiac disease, and the development of techniques for non-invasive imaging of the mouse heart in vivo is, therefore, of great potential interest. Previous magnetic resonance imaging studies have concentrated on pathologically induced changes in cardiac structure and dynamics by acquiring proton images. Further information can be gained by studying cardiac function and physiology using other nuclei, for example, sodium. Sodium imaging of such a small structure presents considerable technical challenges. In this work we show the first sodium images of the mouse heart, with an isotropic spatial resolution of 1 x 1 x 1 mm, acquired in a time of 1.5 h. The ventricles, septum and myocardium are readily distinguishable in these images, which were acquired through the combination of 3D density-weighted chemical shift imaging, optimized instrumentation, and a high magnetic field strength (17.6 T). Measurements of the myocardial:blood sodium concentration in the left and right ventricles agree well with theoretical values.

High-resolution MR imaging of the rat spinal cord in vivo in a wide-bore magnet at 17.6 Tesla

The objective was to demonstrate the feasibility and to evaluate the performance of high-resolution in vivo magnetic resonance (MR) imaging of the rat spinal cord in a 17.6-T vertical wide-bore magnet. A probehead consisting of a surface coil that offers enlarged sample volume suitable for rats up to a weight of 220 g was designed. ECG triggered and respiratory-gated gradient echo experiments were performed on a Bruker Avance 750 wide-bore spectrometer for high-resolution imaging. With T*2 values between 5 and 20 ms, good image contrast could be obtained using short echo times, which also minimizes motion artifacts. Anatomy of healthy spinal cords and pathomorphological changes in traumatically injured rat spinal cord in vivo could be visualized with microscopic detail. It was demonstrated that imaging of the rat spinal cord in vivo using a vertical wide-bore high-magnetic-field system is feasible. The potential to obtain high-resolution images in short scan times renders high-field imaging a powerful diagnostic tool.

The impact of lipid distribution, composition and mobility on xylem water refilling of the resurrection plant Myrothamnus flabellifolia

•  Lipids play a crucial role in the maintenance of the structural and functional integrity of the water-conducting elements and cells of the resurrection plant Myrothamnus flabellifolia during complete dehydration. •  Lipid composition, mobility and distribution within the internodal and nodal xylem regions (including short shoots and leaves) were investigated in the presence and absence of water by using various nuclear magnetic resonance (NMR) spectroscopy and imaging techniques differing greatly in the level of spatial resolution and acquisition of lipid parameters. •  Significant findings include: a discontinuity in the branch xylem between an inner zone where no water moves and an outer zone where the water moves; the blocking of water movement in the inner zone by lipids that are not dispersed by water, and the facilitation of water advance in the xylem elements and pits of the outer zone by water-dispersed lipids; the relative impermeability of leaf trace xylem to the rehydrating water and, hence, the relative hydraulic isolation of the leaves. •  These results elucidated part of the strategy used by the resurrection plant to cope with extreme drought and to minimize transpirational water loss upon hydration.

Release of antimicrobial peptide Dhvar-5 from polymethylmethacrylate beads

Osteomyelitis is still a major cause of morbidity and remains a difficult complication to treat in orthopaedic surgery. The treatment of choice is a combination of systemic and local antibiotics. The insertion of gentamicin-loaded polymethylmethacrylate (PMMA) beads into the bone results in high local concentrations of gentamicin and low systemic concentrations. However, the effectiveness of this treatment is being hampered by the emergence of antimicrobial resistance. New antimicrobial agents are therefore needed. One new class of promising antibiotics is antimicrobial peptides (AMP). Derived from natural human peptides, these have a low tendency to induce antimicrobial resistance. Dhvar-5 is an antimicrobial peptide based on histatin-5, which is found in human saliva and consists of 14 amino acids. It has demonstrated bactericidal activity in vitro. In order to develop a new local treatment using Dhvar-5 for osteomyelitis, we investigated its release from PMMA beads and its antimicrobial activity against a clinical isolate of methicillin-resistant Staphylococcus aureus (MRSA) before and after release from PMMA beads. Specific amounts of Dhvar-5 were incorporated into PMMA mini beads, containing 120, 600 and 1200 microg of Dhvar-5, respectively. Dhvar-5 was released from the beads in all three groups. Total release from the 120 microg beads was 9 microg per bead after 7 days. However, the release per bead in the 600 and 1200 microg beads was far more, respectively, 416 and 1091 microg over a 28 day period. After release, the Dhvar-5 also retained its antimicrobial activity against MRSA. On the basis of these data we conclude that the amount of Dhvar-5 release from PMMA beads is not proportionate to the amount incorporated; instead, it demonstrated an exponential relationship to the amount of total peptide released. Furthermore, the released peptide remained biologically active against a clinical isolate of MRSA.

Review of laparoscopic and open colorectal surgery in the "Zitha" Hospital (Luxembourg) in the year 2002

BACKGROUND

A review and outcome of laparoscopic colorectal surgery in the visceral surgery unit in the Zitha Hospital for the year 2002.

METHODS

All patients, presenting with benign or malignant disease of the colon or rectum were evaluated. Depending on the tumour size, a laparoscopic approach is advocated whenever possible. Operation and patient specific factors (age, duration of the procedure and duration of hospital stay, diagnosis of malignant tumour versus benign disease, conversion and complication rate) are presented. Patients who had to be converted are classified under the open surgery group.

RESULTS

A total of 103 laparoscopic or open procedures on the colon/rectum were performed between the 1st of January 2002 and the 31st of December 2002. 74% were treated by a laparoscopic and 26% by an open approach. 10 out of 103 patients did not undergo a colonic resection but instead an emergency colostomy/ ileostomy or oversewing of a bowel leak, in 8 cases performed laparoscopically. 44 patients have been operated for a benign disease (36 laparoscopic and 8 open procedures) and 59 patients have been treated for a malignant disease (40 laparoscopic and 19 open procedures). The average operating time for the laparoscopic resection was 160 minutes in comparison to 182 minutes for the open resection. The conversion rate (inclusive of non-resection procedures) was 5% for a benign disease and 11% for colorectal cancer. The minor complication rate was 16% in laparoscopic surgery and 30% in open surgery. We saw two major complications in both the open and laparoscopic groups (4%). Reoperation was necessary in one patient out of 103. The average postoperative hospital stay was 7.78 days for the laparoscopic and 16.6 days for the open group. The hospital mortality was 2.9%.

CONCLUSION

The laparoscopic colorectal resection is a safe and beneficial procedure for the patient when used in experienced hands.

Kirsten ras mutations in patients with colorectal cancer: the 'RASCAL II' study

Researchers worldwide with information about the Kirsten ras (Ki-ras) tumour genotype and outcome of patients with colorectal cancer were invited to provide that data in a schematized format for inclusion in a collaborative database called RASCAL (The Kirsten ras in-colorectal-cancer collaborative group). Our results from 2721 such patients have been presented previously and for the first time in any common cancer, showed conclusively that different gene mutations have different impacts on outcome, even when the mutations occur at the same site on the genome. To explore the effect of Ki-ras mutations at different stages of colorectal cancer, more patients were recruited to the database, which was reanalysed when information on 4268 patients from 42 centres in 21 countries had been entered. After predetermined exclusion criteria were applied, data on 3439 patients were entered into a multivariate analysis. This found that of the 12 possible mutations on codons 12 and 13 of Kirsten ras, only one mutation on codon 12, glycine to valine, found in 8.6% of all patients, had a statistically significant impact on failure-free survival (P = 0.004, HR 1.3) and overall survival (P = 0.008, HR 1.29). This mutation appeared to have a greater impact on outcome in Dukes' C cancers (failure-free survival, P = 0.008, HR 1.5; overall survival P = 0.02, HR 1.45) than in Dukes' B tumours (failure-free survival, P = 0.46, HR 1.12; overall survival P = 0.36, HR 1.15). Ki-ras mutations may occur early in the development of pre-cancerous adenomas in the colon and rectum. However, this collaborative study suggests that not only is the presence of a codon 12 glycine to valine mutation important for cancer progression but also that it may predispose to more aggressive biological behaviour in patients with advanced colorectal cancer.

The structure of the coliphage HK022 Nun protein-lambda-phage boxB RNA complex. Implications for the mechanism of transcription termination

Nun protein from coliphage HK022 binds to phage boxB RNA and functions, in contrast to phage lambda N protein, as a transcriptional terminator. The basic Nun-(10-44) peptide contains the boxB RNA binding arginine rich motif, ARM. The peptide binds boxB RNA and competes with the phage lambda ARM peptide N-(1-36) as indicated by nuclear magnetic resonance (NMR) spectroscopy titrations. In two-dimensional nuclear Overhauser enhancement spectroscopy experiments boxB RNA in complex with Nun-(20-44) exhibits the same pattern of resonances as it does in complex with N peptides containing the ARM, and we could show that Nun-(20-44) forms a bent alpha-helix upon binding to the boxB RNA. The structure of the boxB RNA-bound Nun-(20-44) was determined on the basis of 191 intra- and 30 intermolecular distance restraints. Ser-24 is anchored to the lower RNA stem, and stacking of Tyr-39 and A7 is clearly experimentally indicated. Arg-28 shows numerous contacts to the RNA stem. Leu-22, Ile-30, Trp-33, Ile-37, and Leu-41 form a hydrophobic surface, which could be a recognition site for additional host factors such as NusG. Such a hydrophobic surface area is not present in N-(1-36) bound to boxB RNA.