Reactive oxygen homeostasis - the balance for preventing autoimmunity.

Being mainly known for their role in the antimicrobial defense and collateral damage they cause in tissues as agents of oxidative stress, reactive oxygen species were considered "the bad guys" for decades. However, in the last years it was shown that the absence of reactive oxygen species can lead to the development of immune-mediated inflammatory diseases. Animal models of lupus, arthritis and psoriasis revealed reactive oxygen species-deficiency as a potent driver of pathogenesis. On the contrary, in chronic stages oxidative stress can still contribute to progression of inflammation. It seems that a neatly adjusted redox balance is necessary to sustain an immune state that both prevents the development of overt autoimmunity and attenuates chronic stages of disease.

No evidence of pathogenic involvement of cathelicidins in patient cohorts and mouse models of lupus and arthritis.

Apart from their role in the immune defence against pathogens evidence of a role of antimicrobial peptides (AMPs) in autoimmune diseases has accumulated in the past years. The aim of this project was to examine the functional impact of the human cathelicidin LL-37 and the mouse cathelicidin-related AMP (CRAMP) on the pathogenesis of lupus and arthritis. Serum LL-37 and anti-LL-37 levels were measured by ELISA in healthy donors and patients with Systemic Lupus Erythematosus (SLE) and Rheumatoid arthritis (RA). Pristane-induced lupus was induced in female wild type (WT) and cathelicidin-deficient (CRAMP-/-) mice. Serum levels of anti-Sm/RNP, anti-dsDNA, and anti-histone were determined via ELISA, cytokines in sera and peritoneal lavages were measured via Multiplex. Expression of Interferon I stimulated genes (ISG) was determined by real-time PCR. Collagen-induced arthritis (CIA) was induced in male WT and CRAMP-/- mice and arthritis severity was visually scored and analysed histomorphometrically by OsteoMeasure software. Serum levels of anti-LL-37 were higher in SLE-patients compared to healthy donors or patients with RA. However, no correlation to markers of disease activity or organ involvement was observed. No significant differences of autoantibody or cytokine/chemokine levels, or of expression of ISGs were observed between WT and CRAMP-/- mice after pristane-injection. Furthermore, lung and kidney pathology did not differ in the absence of CRAMP. Incidence and severity of CIA and histological parameters (inflammation, cartilage degradation, and bone erosion) were not different in WT and CRAMP-/- mice. Although cathelicidins are upregulated in mouse models of lupus and arthritis, cathelicidin-deficiency did not persistently affect the diseases. Also in patients with SLE, autoantibodies against cathelicidins did not correlate with disease manifestation. Reactivity against cathelicidins in lupus and arthritis could thus be an epiphenomenon caused by extensive overexpression in blood and affected tissues. In addition, other cationic AMPs could functionally compensate for the deficiency of cathelicidins.

[Automatic phase point determination of minimal motion reconstruction intervals with motion maps in ECG-gated CT diagnostics of coronary sclerosis]. / Die automatisierte Bestimmung eines optimalen Rekonstruktionsintervalls bei der nativen EKG-gegateten CT-Diagnostik der Koronarsklerose mittels "Motion Maps".

PURPOSE: Cardio-CT motion maps for automated cardiac phase point determination were evaluated for image quality and reliability of coronary calcium scores. MATERIALS AND METHODS: 24 patients underwent ECG-gated non-enhanced cardiac CT for calcium scoring. From raw data the motion map software reconstructed low-resolution images in 2 % steps of the RR interval and automatically generated cardiac motion maps for determination of minimal motion phase points. Diagnostic images were reconstructed in 10% steps of the RR interval (RR data) and according to the motion maps (MM data). For every data set, the Agatston score was calculated. Image quality was evaluated by two independent observers. Image quality was correlated with the Agatston score. RESULTS: The Agatston score calculated over the RR interval showed a mean variation of 127 with 41% of patients assigned to more than one risk group. If the motion map RR intervals were calculated, only 16% patients were assigned to different risk categories with a mean variation of 55. Regarding the image quality, the inter-rater variance was moderate. The best image quality was achieved with the 30 - 40% and 70 - 80% RR interval. Over the complete RR interval motion map reconstructions produced a good image quality. CONCLUSION: Calculation of the Agatston score requires selection of the proper reconstruction interval to guarantee the assignment of patients into the appropriate risk category. By using motion maps for phase point determination, the amount of necessary reconstruction can be minimized and the assignment to different risk groups is also reduced.

Evaluation of acute mesenteric ischemia: accuracy of biphasic mesenteric multi-detector CT angiography.

The purpose of this study was to explore the accuracy of multi-detector row helical CT (MDCT), using a biphasic mesenteric angiography protocol for evaluation of acute mesenteric ischemia (AMI). In total, 79 consecutive patients with clinical signs of AMI underwent contrast enhanced 16- or 40-channel MDCT. MDCT findings were correlated with surgery, endoscopy and clinical outcome. Sensitivity, specificity, and positive and negative predictive values were calculated using the patients in which AMI had been excluded as a control group. In 28 patients the final diagnosis was AMI. In 27 patients (96.4%) MDCT correctly diagnosed AMI (specificity of 97.9%). A sensitivity of 93%, specificity of 100%, and positive and negative predictive values of 100% and 94%, respectively were achieved for the CT findings of visceral artery occlusion, intestinal pneumatosis, portomesenteric venous gas or bowel wall thickening in combination with either portomesenteric thrombosis or solid organ infarction. Our findings suggest that mesenteric MDCT angiography is an accurate tool for fast diagnostic work-up of patients with suspected AMI.

Pitfalls in detection of acute gastrointestinal bleeding with multi-detector row helical CT.

Contrast-enhanced multi-detector row helical CT angiography is establishing itself as an accurate, rapid, and non-invasive diagnostic modality in patients with acute gastrointestinal bleeding. On arterial phase MDCT images ongoing hemorrhage can be revealed as an area of active extravasation of contrast material within the bowel lumen. This pictorial essay gives a short overview of current diagnostic modalities in assessing acute GI tract bleeding, typical MDCT findings, and depicts potential pitfalls in the detection of acute GI bleeding with MDCT.

MR imaging and quantification of the movement of the lamina terminalis depending on the CSF dynamics.

BACKGROUND AND PURPOSE: Brain pulsation is a well-known observation in neurosurgery, but methods for its visualization on MR imaging, like phase imaging, do not provide a detailed structural view. We prospectively investigated electrocardiographic (ECG)-gated cine true fast imaging with steady-state precession (FISP) sequence on volunteers to test a sequence for demonstrating brain pulsation and movements of intracranial structures related to CSF dynamics. MATERIALS AND METHODS: Eleven healthy volunteers were investigated with prospectively ECG-gated cine true-FISP in the midsagittal plane. A total of 50 phases were recorded per cardiac cycle and per volunteer. The lamina terminalis was chosen to study the pulsatility of the brain, and the optic recess diameter was chosen for means of objective quantification of the degree of pulsatility. RESULTS: Pulsatile motion of the lamina terminalis was apparent in all volunteers on the cine mode. The mean diameter of the optic recess was 2.5 mm. The greatest change in diameter in 1 volunteer was 1.5 mm. The mean change in diameter was 40% during 1 cardiac cycle. CONCLUSIONS: Cine true-FISP sequence is a well-suited method for investigations of passive movements of the ventricular system. It shows pulsations of the brain as well as passive changes caused by CSF dynamics with high temporal and spatial resolution.

Evaluation of accordance of magnetic resonance volumetric and flow measurements in determining ventricular stroke volume in cardiac patients.

BACKGROUND: Cardiovascular magnetic resonance imaging (CMR) has become an established noninvasive method for evaluating ventricular function utilizing three-dimensional volumetry. Postprocessing of volumetric measurements is still tedious and time consuming. Stroke volumes obtained by flow quantification across the aortic root or pulmonary trunk could be utilized to increase both speed of workflow and accuracy. PURPOSE: To assess accuracy of stroke volume quantification using MR volumetric imaging compared to flow quantification in patients with various cardiac diseases. Strategies for the augmentation of accuracy in clinical routine were deduced. MATERIAL AND METHODS: 78 patients with various cardiac diseases-excluding intra- or extracardiac shunts, regurgitant valvular defects, or heart rhythm disturbance-underwent cardiac function analysis with flow measurements across the aortic root and cine imaging of the left ventricle. Forty-six patients additionally underwent flow measurements in the pulmonary trunk and cine imaging of the right ventricle. RESULTS: Left ventricular stroke volume (LVSV) and stroke volume of the aortic root (SVAo) correlated with r=0.97, and Bland-Altman analysis showed a mean difference of 0.11 ml and a standard error of estimation (SEE) of 4.31 ml. Ninety-two percent of the data were within the 95% limits of agreement. Right ventricular stroke volume (RVSV) and stroke volume of the pulmonary trunk (SVP) correlated with a factor of r=0.86, and mean difference in the Bland-Altman analysis was fixed at -2.62 ml (SEE 8.47 ml). For RVSV and SVP, we calculated r=0.82, and Bland-Altman analysis revealed a mean difference of 1.27 ml (SEE 9.89 ml). LVSV and RVSV correlated closely, with r=0.91 and a mean difference of 2.79 ml (SEE 7.17 ml). SVAo and SVP correlated with r=0.95 and a mean difference of 0.50 ml (SEE 5.56 ml). CONCLUSION: Flow quantification can be used as a guidance tool, providing accurate and reproducible stroke volumes of both ventricles. Combining both offers a highly accurate tool to gauge ventricular function in a routine clinical setting, increasing workflow speed.

Detection and localization of acute upper and lower gastrointestinal (GI) bleeding with arterial phase multi-detector row helical CT.

The purpose of this study was to evaluate the accuracy of multi-detector row helical CT (MDCT) for detection and localization of acute upper and lower gastrointestinal (GI) hemorrhage or intraperitoneal bleeding. Thirty-six consecutive patients with clinical signs of acute bleeding underwent biphasic (16- or 40-channel) MDCT. MDCT findings were correlated with endoscopy, angiography or surgery. Among the 36 patients evaluated, 26 were examined for GI bleeding and 10 for intraperitoneal hemorrhage. Confirmed sites of GI bleeding were the stomach (n = 5), duodenum (n = 5), small bowel (n = 6), large bowel (n = 8) and rectum (n = 2). The correct site of bleeding was identifiable on MDCT in 24/26 patients with GI bleeding. In 20 of these 24 patients, active CM extravasation was apparent during the exam. Among the ten patients with intraperitoneal hemorrhage, MDCT correctly identified the bleeding source in nine patients. Our findings suggest that fast and accurate localization of acute gastrointestinal and intraperitoneal bleeding is achievable on MDCT.

Acute gastrointestinal bleeding: value of MDCT.

Contrast-enhanced multidetector row helical computed tomography (MDCT) scanning is establishing itself as a rapid, noninvasive, and accurate diagnostic method in suspected acute gastrointestinal bleeding. Active bleeding can be depicted as an area of focal high attenuation within the bowel lumen on arterial phase MDCT images. New MDCT technologies facilitate three-dimensional image reconstruction, and higher temporal resolution is available with new MDCT scanner generations. This allows for the acquisition of arterial- and portal-venous phase images of the whole abdomen, revealing potential bleeding sources and simultaneously depict morphological changes in the abdomen, such as intestinal tumors. This article gives an overview of available diagnostic modalities in assessing gastrointestinal (GI) tract hemorrhage, with a special emphasis on new MDCT technology.

Transgenic GFP as a molecular marker for approaches to quantify pollination mechanism and gene flow in Arabidopsis thaliana.

Arabidopsis thaliana is commonly regarded as a self-pollinated plant. We observed that the stigma in each flower of A. thaliana cannot be pollinated by its own pollen in the early phases of the flowering process, when the anthers had dehisced but the filaments were still too short for the pollen to be deposited on the stigma. In the later stages, after elongation of the filaments, self-pollination can occur. After artificial pollination of the flower of a wild plant with GFP transgenic pollen grains in earlier stages of flowering, GFP expressed within epidermal cells was detected in some of the offspring (26.1-57.1 %). Wind-mediated pollen dispersal was poor but is likely to exist in natural habitats, while insects were observed visiting flowers of A. thaliana in natural and experimental populations. We constructed an experimental population consisting of 28 GFP transgenic plants and 240 wild plants and examined gene flow in the population. The result was that the distance of gene flow was limited to 0.5 m. 22 offspring with expressed GFP were found in 28,299 filial individuals examined, which suggested a relatively low outcrossing rate (0.74%). We conclude that outcrossing in populations of A. thaliana is mainly due to insect pollination. The data on gene flow could be useful to assess the ecological hazards of experimental transgene combinations.

Multiple platelet defects identified by flow cytometry at diagnosis in acute myeloid leukaemia.

Summary Previous findings of megakaryocytic hypogranulation and dysmegakaryocytopoietic features in acute myeloid leukaemia (AML) strongly indicate defects in platelet production. The bleeding tendency of these patients may result from dysregulated platelet production, resulting in thrombocytopenia as well as qualitative platelet defects. The present study examined platelet function at diagnosis in 50 AML patients by whole blood flow cytometry. Following in vitro platelet agonist stimulation, platelet activation markers were analysed and compared with 20 healthy individuals. To detect recent in vivo platelet activation, plasma soluble P-selectin (sP-selectin) was measured. Flow cytometric analysis of platelet activation markers demonstrated reduced CD62P [35.6 vs. 118.5 x 10(3) molecules of equivalent soluble fluorochrome (MESF); P < 0.0001], CD63 (11.3 vs. 50.7 x 10(3) MESF; P < 0.0001), and PAC-1 (41.5 vs. 90.5%; P = 0.0001) while reductions in CD42b were abnormal (45.6 vs. 70%; P < 0.0001). sP-selectin levels were similar in patients and healthy controls (0.04 vs. 0.27 fg/platelet; P = 0.84). The presented data indicate that AML pathogenesis may result in multiple platelet defects, involving adhesion, aggregation, and secretion and demonstrate that flow cytometry is a feasible method for platelet function analysis in patients with thrombocytopenia.

Geographic distribution and recombination of genomic fragments on the short arm of chromosome 2 of Arabidopsis thaliana.

Range expansion from Pleistocene refugia and anthropogenic influences contribute to the present distribution pattern of Arabidopsis thaliana. We scored a genome-wide set of CAPSs and found two markers with an east-west geographic distribution across the Eurasian range of the species. Regions around the two SNPs were sequenced in 98 accessions, including newly collected plants from Middle Asia and Western Siberia. These regions correspond to a gene ( approximately 1500 bp) and a non-coding region ( approximately 500 bp) 300 kbp apart on chromosome 2. Nucleotide diversities, pi, of the two sequenced fragments were 0.0032 and 0.0130. The haplotypes of both sequences belonged to one of two groups: a rather uniform "Asian" and a more variable "European" haplotype group, on the basis of non-disjunct clusters of SNPs. Recombination between "Asian" and "European" haplotypes occurs where they meet. Especially in the "European" haplotype, many rare SNP variants representing independent mutations are scattered among the shared haplotype-specific SNPs. This agrees with previous suggestions of two large haplotype groups in A. thaliana and the post-glacial colonization of central Europe from the east and the west. A clear correlation between climatic factors and the haplotype distribution may reflect the dispersal history rather than local climate adaptation. The pattern of SNP variation within the contiguous sequences explains why only a minority of SNPs selected across the genome show evidence of this geographic pattern.

Assessing agreement between CD34 enumeration by flow cytometry and volumetric analysis.

Prior to replacement of an established method for CD34 enumeration by an alternative approach, evaluation of the agreement between the methods is essential. In this study, the comparison of two assays was evaluated according to the recommendation of Bland and Altman describing the agreement between two methods where the true value is not known. CD34 enumeration was performed on blood or leukapheresis product from 105 patients by flow cytometry (dual platform assay) and volumetric analysis (single platform assay). Both the flow cytometric and the volumetric analysis showed poor reproducibility for measures lower than approximately 9 CD34+ cells/mm3. For values higher than 29 CD34+ cells/mm3, evaluation of the agreement demonstrated a difference between the single and dual platform assay, where CD34 enumeration by the volumetric analysis demonstrated values 73-80% of the flow cytometric value. The difference between the two assays could be due to several technical pitfalls which are discussed.

[DiGeorge syndrome. Velocardiofacial syndrome/chromosome 22q11 deletion syndrome]. / DiGeorges syndrom. Velokardiofacialt syndrom/kromosom 22q11-deletionssyndrom.

Patients with a deletion of chromosome band 22q11 are described as having DiGeorges syndrome, velocardiofacial syndrome or chromosome 22q11 deletion syndrome depending on clinical manifestations. The patients have variable severity and combinations of conotruncal heart defects, abnormalities of the ear and palate, facial dysmorphism and mental retardation as well as partial or complete aplasia/hypoplasia of the thymus and endocrine dysfunction, e.g. hypoparathyroidism. The patients may present with impaired immune function, heart failure, hypocalcaemia, facial dysmorphism, impaired hearing and mental retardation. The syndrome, which is a significant cause of heart and craniofacial defects as well as mental retardation, is probably underdiagnosed. In each of the above mentioned phenotypical presentations, chromosome 22q11 deletion syndrome should be considered.

[DiGeorge syndrome diagnosed in a 39-year old woman with chronic hypocalcemia]. / DiGeorges syndrom diagnosticeret hos en 39-årig kvinde med kronisk hypokalcaemi.

A 39 year-old woman was diagnosed with DiGeorge's syndrome based on newly diagnosed hypocalcaemia, appearance and history. The patient had congenital cardiovascular malformations, mild mental retardation and ear malformations, and during infancy and childhood suffered from failure to thrive and frequent infections. In children with conotruncal heart malformation, hypocalcaemia and hypoplasia of the thymus in combination it is estimated that chromosome 22q11 deletion is present in almost 100%. The syndrome is probably underdiagnosed.

Myelopathy associated with human T cell lymphotropic virus type I (HTLV-I) in natal, South Africa. A clinical and investigative study in 24 patients.

Unexplained spastic myelopathy in black (Zulu) patients, similar to that seen in the tropics, has previously been described from Natal, South Africa. Following reports linking the human T cell lymphotropic virus type I (HTLV-I) to spastic myelopathy, we undertook a prospective and retrospective search for HTLV-I antibodies in 36 patients who were labelled as having unexplained myelopathy; 24 (66%) were positive and HTLV-I was isolated from 4 out of the 6 patients whose peripheral blood lymphocytes were cultured. Eighteen (75%) gave a short history (less than 6 months). There was a female preponderance (71%), spinothalamic dysfunction was common (55%) and as many as half were severely disabled (50% wheelchair bound). Routine laboratory studies showed no specific trends apart from hypergammaglobulinaemia and CSF pleocytosis (greater than 5 cells/microliter in 66% of patients). The total CSF protein was raised (greater than 0.4 g/l) in 45% of patients. The IgG index was greater than 0.7 in 15 of 19 patients. Conventional myelography did not show any specific abnormalities. Computer assisted myelography was undertaken in 22 patients; 3 showed arachnoiditis and 2 spinal cord atrophy. Periventricular lucencies were seen in 1 of 10 patients who had computed tomography of the head. Nerve conduction studies demonstrated abnormalities in 46% of the patients indicating that subclinical peripheral nerve dysfunction was common. Visual evoked responses were abnormal in only 1 patient but brainstem auditory evoked response studies showed some abnormality in 42% of the patients. The finding of HTLV-I antibodies in a significant number, and the isolation of HTLV-I from the blood in 6 of our black patients with noncompressive myelopathy, represents a substantial clinical advance. Future studies should define more clearly the role of the virus in this disorder.