Medizin - Open Access LMU - Teil 14/22 Archiv

As a luminogram, coronary angiography provides a good overview of the coronary artery tree. Using quantitative coronary measurements, the degree of coronary obstruction can be determined. The limitation of coronary angiography is that it does not provide information on the arterial wall structure and therefore cannot assess the extent of atherosclerosis. Knowledge about adaptive coronary remodelling processes as compensatory enlargement of the coronary artery has focused diagnostic interest on the non-stenotic lesions of the coronary tree. Intravascular ultrasound (IVUS) can reveal discrepancies between the extent of coronary atherosclerosis and angiography imaging by in vivo plaque imaging. Spectrum analysis of IVUS-derived radiofrequency (RF) data enables a more detailed analysis of plaque composition and morphology. Preliminary in vitro studies correlated four histological plaque components with a specific spectrum analysis of the RF data. The different components (fibrous, fibrofatty, necrotic core and dense calcium) are colour coded. Coronary tissue maps were reconstructed from RF data using IVUS–Virtual Histology (VH IVUS) software (Real-Time VH, Volcano Corporation, Rancho Cordova, California, USA). VH IVUS has the potential to detect high-risk lesions and can provide new insights into the pathophysiology of coronary artery disease. VH IVUS allows the differentiation of different lesion types based on information derived from histopathology. The in vivo specific histological analysis of coronary atherosclerosis may allow better stratification of treatment of patients with coronary artery disease.

Es wird der Fall einer Patientin mit Dissoziativer Identitätsstörung vorgestellt, die nach 15-jähriger, als kortikal diagnostizierter Blindheit im Laufe einer psychotherapeutischen Behandlung schrittweise wieder zu sehen begann. Zunächst konnten nur einige wenige Persönlichkeitsanteile wieder sehen, während andere weiterhin blind waren. Dies konn-te durch elektrophysiologische Untersuchungen bestätigt werden, in denen die noch blinden Persönlichkeitsanteile ausbleibende, die sehenden Persönlichkeitsanteile hin-gegen völlig unauffällige, reguläre evozierte Potentiale aufwiesen. Das Umschalten zwi-schen sehenden und blinden Anteilen konnte übergangslos geschehen. Als neuronale Grundlage der psychogenen Blindheit kommt eine „top-down“ Modulation der Aktivität der primären Sehbahn, auf Ebene des Thalamus oder primären visuellen Kortex, in Be-tracht. Mittels VEP-Untersuchungen kann daher eine psychogene Blindheit nicht von organischen Ursachen einer Unterbrechung der Sehbahn abgegrenzt werden. Zusam-menfassend scheint psychogene Blindheit den Zufluß visueller Information auf früher Stufe zu blockieren.

Because of the widespread phenomenon of patrilocality, it is hypothesized that Y-chromosome variants tend to be more localized geographically than those of mitochondrial DNA ( mtDNA). Empirical evidence confirmatory to this hypothesis was subsequently provided among certain patrilocal and matrilocal groups of Thailand, which conforms to the isolation by distance mode of gene diffusion. However, we expect intuitively that the patterns of genetic variability may not be consistent with the above hypothesis among populations with different social norms governing the institution of marriage, particularly among those that adhere to strict endogamy rules. We test the universality of this hypothesis by analyzing Y-chromosome and mtDNA data in three different sets of Indian populations that follow endogamy rules to varying degrees. Our analysis of the Indian patrilocal and the matrilocal groups is not confirmatory to the sex- specific variation observed among the tribes of Thailand. Our results indicate spatial instability of the impact of different cultural processes on the genetic variability, resulting in the lack of universality of the hypothesized pattern of greater Y-chromosome variation when compared to that of mtDNA among the patrilocal populations.

The dosage compensation complex (DCC) in Drosophila melanogaster is responsible for up-regulating transcription from the single male X chromosome to equal the transcription from the two X chromosomes in females. Visualization of the DCC, a large ribonucleoprotein complex, on male larval polytene chromosomes reveals that the complex binds selectively to many interbands on the X chromosome. The targeting of the DCC is thought to be in part determined by DNA sequences that are enriched on the X. So far, lack of knowledge about DCC binding sites has prevented the identification of sequence determinants. Only three binding sites have been identified to date, but analysis of their DNA sequence did not allow the prediction of further binding sites. We have used chromatin immunoprecipitation to identify a number of new DCC binding fragments and characterized them in vivo by visualizing DCC binding to autosomal insertions of these fragments, and we have demonstrated that they possess a wide range of potential to recruit the DCC. By varying the in vivo concentration of the DCC, we provide evidence that this range of recruitment potential is due to differences in affinity of the complex to these sites. We were also able to establish that DCC binding to ectopic high-affinity sites can allow nearby low-affinity sites to recruit the complex. Using the sequences of the newly identified and previously characterized binding fragments, we have uncovered a number of short sequence motifs, which in combination may contribute to DCC recruitment. Our findings suggest that the DCC is recruited to the X via a number of binding sites of decreasing affinities, and that the presence of high-and moderate-affinity sites on the X may ensure that lower-affinity sites are occupied in a context-dependent manner. Our bioinformatics analysis suggests that DCC binding sites may be composed of variable combinations of degenerate motifs.

Background: Alkylphosphocholines constitute a novel class of antineoplastic synthetic phospholipid derivatives that induce apoptosis of human tumor cell lines by targeting cellular membranes. We could recently show that the first intravenously applicable alkylphosphocholine erucylphosphocholine (ErPC) is a potent inducer of apoptosis in highly resistant human astrocytoma/glioblastoma cell lines in vitro. ErPC was shown to cross the blood brain barrier upon repeated intravenous injections in rats and thus constitutes a promising candidate for glioblastoma therapy. Aim of the present study was to analyze putative beneficial effects of ErPC and its clinically more advanced derivative erucylphosphohomocholine (erucyl-N, N, N-trimethylpropanolaminphosphate, ErPC3, Erufosine (TM) on radiation-induced apoptosis and eradication of clonogenic tumor cells in human astrocytoma/glioblastoma cell lines in vitro. Results: While all cell lines showed high intrinsic resistance against radiation-induced apoptosis as determined by fluorescence microscopy, treatment with ErPC and ErPC3 strongly increased sensitivity of the cells to radiation-induced cell death (apoptosis and necrosis). T98G cells were most responsive to the combined treatment revealing highly synergistic effects while A172 showed mostly additive to synergistic effects, and U87MG cells sub-additive, additive or synergistic effects, depending on the respective radiation-dose, drug-concentration and treatment time. Combined treatment enhanced therapy-induced damage of the mitochondria and caspase-activation. Importantly, combined treatment also increased radiation-induced eradication of clonogenic T98G cells as determined by standard colony formation assays. Conclusion: Our observations make the combined treatment with ionizing radiation and the membrane targeted apoptosis modulators ErPC and ErPC3 a promising approach for the treatment of patients suffering from malignant glioma. The use of this innovative treatment concept in an in vivo xenograft setting is under current investigation.

Background: Adiponectin acts as an antidiabetic, antiinflammatory and antiatherogenic adipokine. These effects are assumed to be mediated by the recently discovered adiponectin receptors AdipoR1 and AdipoR2. Aim: The purpose of this study was to determine whether variations in the AdipoR1 and AdipoR2 genes may contribute to insulin resistance, dyslipidemia and inflammation. Methods: We sequenced all seven coding exons of both genes in 20 unrelated German subjects with metabolic syndrome and tested genetic variants for association with glucose, lipid and inflammatory parameters. Results: We identified three AdipoR2 variants (+795G/ A, +870C/A and +963C/T) in perfect linkage disequilibrium (r(2) = 1) with a minor allele frequency of 0.125. This haplotype was associated with higher plasma adiponectin levels and decreased fasting triglyceride, VLDL-triglyceride and VLDL-cholesterol levels. No association, however, was observed between the AdipoR2 SNP cluster and glucose metabolism. Conclusion: To our knowledge, this is the first study to identify an association between genetic variants of the adiponectin receptor genes and plasma adiponectin levels. Furthermore, our data suggest that AdipoR2 may play an important role in triglyceride/VLDL metabolism.

Peptidylarginine deiminase type 4 (PADI4) genotypes were shown to influence susceptibility to rheumatoid arthritis ( RA) in the Japanese population. Such an association could not previously be confirmed in different European populations. In the present study, we analysed exons 2 - 4 of PADI4 in 102 German RA patients and 102 healthy individuals to study the influence of PADI4 variability on RA susceptibility by means of haplotype-specific DNA sequencing. Analyses of the influence of PADI4 and HLA-DRB1 genotypes on disease activity and on levels of anti-cyclic citrullinated peptide antibodies were performed. Comparing the frequencies of PADI4 haplotype 4 (padi4\_89* G, padi4\_90* T, padi4\_92* G, padi4\_94* T, padi4\_104* C, padi4\_95* G, padi4\_96* T) ( patients, 14.7%; controls, 7.8%; odds ratio = 2.0, 95% confidence interval = 1.1 - 3.8) and carriers of this haplotype ( patients, 27.5%; controls, 13.7%; odds ratio = 2.4, 95% confidence interval = 1.2 - 4.8), a significant positive association of PADI4 haplotype 4 with RA could be demonstrated. Other PADI4 haplotypes did not differ significantly between patients and controls. Regarding the individual PADI4 variants, padi4\_89 ( A. G), padi4\_90 (C --> T), and padi4\_94 (C --> T) were significantly associated with RA ( patients, 49.5%; controls, 38.7%; odds ratio = 1.6, 95% confidence interval = 1.1 - 2.3). Considering novel PADI4 variants located in or near to exons 2, 3, and 4, no quantitative or qualitative differences between RA patients (8.8%) and healthy controls (10.8%) could be demonstrated. While the PADI4 genotype did not influence disease activity and the anticyclic citrullinated peptide antibody level, the presence of the HLA-DRB1 shared epitope was significantly associated with higher anti-cyclic citrullinated peptide antibody levels ( P = 0.033). The results of this small case - control study support the hypothesis that variability of the PADI4 gene may influence susceptibility to RA in the German population. Quantitative or qualitative differences in previously undefined PADI4 variants between patients and controls could not be demonstrated.

Functioning is recognized as an important study outcome in rheumatoid arthritis ( RA). The Comprehensive ICF Core Set for RA is an application of the International Classification of Functioning, Disability and Health ( ICF) of the World Health Organisation with the purpose of representing the typical spectrum of functioning of patients with RA. To strengthen the patient perspective, persons with RA were explicitly involved in the validation of the Comprehensive ICF Core Set for RA using qualitative methodology. The objective of the study was twofold: to come forward with a proposal for the most appropriate methodology to validate Comprehensive ICF Core Sets from the patient perspective; and to add evidence to the validation of the Comprehensive ICF Core Set for RA from the perspective of patients. The specific aims were to explore the aspects of functioning and health important to patients with RA using two different focus group approaches ( open approach and ICF-based approach) and to examine to what extent these aspects are represented by the current version of the Comprehensive ICF Core Set for RA. The sampling of patients followed the maximum variation strategy. Sample size was determined by saturation. The focus groups were digitally recorded and transcribed verbatim. The meaning condensation procedure was used for the data analysis. After qualitative data analysis, the resulting concepts were linked to ICF categories according to established linking rules. Forty-nine patients participated in ten focus groups ( five in each approach). Of the 76 ICF categories contained in the Comprehensive ICF Core Set for RA, 65 were reported by the patients based on the open approach and 71 based on the ICF-based approach. Sixty-six additional categories ( open approach, 41; ICF-based approach, 57) that are not covered in the Comprehensive ICF Core Set for RA were raised. The existing version of the Comprehensive ICF Core Set for RA could be confirmed almost entirely by the two different focus group approaches applied. Focus groups are a highly useful qualitative method to validate the Comprehensive ICF Core Set for RA from the patient perspective. The ICF-based approach seems to be the most appropriate technique.

Background: The loss of alveolar walls is a hallmark of emphysema. As fibroblasts play an important role in the maintenance of alveolar structure, a change in fibroblast phenotype could be involved in the pathogenesis of this disease. In a previous study we found a reduced in vitro proliferation rate and number of population doublings of parenchymal lung fibroblasts from patients with emphysema and we hypothesized that these findings could be related to a premature cellular aging of these cells. In this study, we therefore compared cellular senescence markers and expression of respective genes between lung fibroblasts from patients with emphysema and control patients without COPD. Methods: Primary lung fibroblasts were obtained from 13 patients with moderate to severe lung emphysema ( E) and 15 controls ( C) undergoing surgery for lung tumor resection or volume reduction ( n = 2). Fibroblasts (8E/9C) were stained for senescence- associated beta-galactosidase (SA-beta-Gal). In independent cultures, DNA from lung fibroblasts (7E/8C) was assessed for mean telomere length. Two exploratory 12 k cDNA microarrays were used to assess gene expression in pooled fibroblasts (3E/ 3C). Subsequently, expression of selected genes was evaluated by quantitative PCR (qPCR) in fibroblasts of individual patients (10E/9C) and protein concentration was analyzed in the cell culture supernatant. Results: The median ( quartiles) percentage of fibroblasts positive for SA-beta-Gal was 4.4 (3.2; 4.7) % in controls and 16.0 (10.0; 24.8) % in emphysema ( p = 0.001), while telomere length was not different. Among the candidates for differentially expressed genes in the array ( factor = 3), 15 were upregulated and 121 downregulated in emphysema. qPCR confirmed the upregulation of insulin-like growth factor-binding protein ( IGFBP)-3 and IGFBP-rP1 ( p = 0.029, p = 0.0002), while expression of IGFBP-5, - rP2 ( CTGF), - rP4 (Cyr61), FOSL1, LOXL2, OAZ1 and CDK4 was not different between groups. In line with the gene expression we found increased cell culture supernatant concentrations of IGFBP-3 ( p = 0.006) in emphysema. Conclusion: These data support the hypothesis that premature aging of lung fibroblasts occurs in emphysema, via a telomere-independent mechanism. The upregulation of the senescence- associated IGFBP-3 and - rP1 in emphysema suggests that inhibition of the action of insulin and insulin-like growth factors could be involved in the reduced in vitro-proliferation rate.

Background: Airway smooth muscle cells (ASMC) play a key role in bronchial hyperresponsiveness (BHR). A major component of the signaling cascade leading to ASMC contraction is calcium. So far, agonist-induced Ca2+-signaling in asthma has been studied by comparing innate properties of inbred rat or mouse strains, or by using selected mediators known to be involved in asthma. T-bet knock-out (KO) mice show key features of allergic asthma such as a shift towards T(H)2-lymphocytes and display a broad spectrum of asthma-like histological and functional characteristics. In this study, we aimed at investigating whether Ca2+-homeostasis of ASMC is altered in T-bet KO-mice as an experimental model of asthma. Methods: Lung slices of 100 to 200 mu m thickness were obtained from T-bet KO- and wild-type mice. Airway contraction in response to acetylcholine (ACH) was measured by video-microscopy and Ca2+-signaling in single ASMC of lung slices was assessed using two-photon-microscopy. Results: Airways from T-bet KO-mice showed increased baseline airway tone (BAT) and BHR compared to wild-type mice. This could be mimicked by incubation of lung slices from wild-type mice with IL-13. The increased BAT was correlated with an increased incidence of spontaneous changes in intracellular Ca2+-concentrations, whereas BHR correlated with higher ACH-induced Ca2+-transients and an increased proportion of ASMC showing Ca2+-oscillations. Emptying intracellular Ca2+-stores using caffeine or cyclopiazonic acid induced higher Ca2+-elevations in ASMC from T-bet KO- compared to wild-type mice. Conclusion: Altered Ca2+-homeostasis of ASMC contributes to increased BAT and BHR in lung slices from T-bet KO-mice as a murine asthma model. We propose that a higher Ca2+-content of the intracellular Ca2+-stores is involved in the pathophysiology of these changes.

Background: Children with congenital hearing impairment benefit from early detection and management of their hearing loss. These and related considerations led to the recommendation of universal newborn hearing screening. In 2001 the first phase of a national Newborn Hearing Screening Programme (NHSP) was implemented in England. Objective of this study was to assess costs and effectiveness for hospital and community-based newborn hearing screening systems in England based on data from this first phase with regard to the effects of alterations to parameter values. Methods: Design: Clinical effectiveness analysis using a Markov Model. Outcome measure: quality weighted detected child months (QCM). Results: Both hospital and community programmes yielded 794 QCM at the age of 6 months with total costs of 3,690,000 pound per 100,000 screened children in hospital and 3,340,000 pound in community. Simulated costs would be lower in hospital in 48% of the trials. Any statistically significant difference between hospital and community in prevalence, test sensitivity, test specificity and costs would result in significant differences in cost-effectiveness between hospital and community. Conclusion: This modelling exercise informs decision makers by a quantitative projection of available data and the explicit and transparent statements about assumptions and the degree of uncertainty. Further evaluation of the cost-effectiveness should focus on the potential differences in test parameters and prevalence in these two settings.

Background: Inspiratory activity is a prerequisite for successful application of patient triggered ventilation such as proportional assist ventilation (PAV). It has recently been reported that surfactant instillation increases the activity of slowly adapting pulmonary stretch receptors (PSRs) followed by a shorter inspiratory time (Sindelar et al, J Appl Physiol, 2005 [Epub ahead of print]). Changes in lung mechanics, as observed in preterm infants with respiratory distress syndrome and after surfactant treatment, might therefore influence the inspiratory activity when applying PAV early after surfactant treatment. Objective: To investigate the regulation of breathing and ventilatory response in surfactant-depleted young cats during PAV and during continuous positive airway pressure ( CPAP) early after surfactant instillation in relation to phrenic nerve activity (PNA) and the activity of PSRs. Methods: Seven anesthetized, endotracheally intubated young cats were exposed to periods of CPAP and PAV with the same end-expiratory pressure (0.2 - 0.5 kPa) before and after lung lavage and after surfactant instillation. PAV was set to compensate for 75% of the lung elastic recoil. Results: Tidal volume and respiratory rate were higher with lower PaCO2 and higher PaO2 during PAV than during CPAP both before and after surfactant instillation ( p < 0.05; both conditions). As an indicator of breathing effort, esophageal deflection pressure and PNA were lower during PAV than during CPAP in both conditions ( p < 0.02). Peak PSR activity was higher and occurred earlier during PAV than during CPAP ( p < 0.01), and correlated linearly with PNA duration in all conditions studied ( p < 0.001). The inspiratory time decreased as tidal volume increased when CPAP was changed to PAV, with the highest correlation observed after surfactant instillation ( r = - 0.769). No apneic periods could be observed. Conclusion: PSR activity and the control of breathing are maintained during PAV in surfactant-depleted cats early after surfactant instillation, with a higher ventilatory response and a lower breathing effort than during CPAP.

Background: Gastric carcinoma is one of the most frequent cancers worldwide. Patients with gastric cancer at an advanced disease stage have a poor prognosis, due to the limited efficacy of available therapies. Therefore, the development of new therapies, like immunotherapy for the treatment of gastric cancer is of utmost importance. Since the usability of existing preclinical models for the evaluation of immunotherapies for gastric adenocarcinomas is limited, the goal of the present study was to establish murine in vivo models which allow the stepwise improvement of immunotherapies for gastric cancer. Methods: Since no murine gastric adenocarcinoma cell lines are available we established four cell lines (424GC, mGC3, mGC5, mGC8) from spontaneously developing tumors of CEA424/SV40 T antigen (CEA424/Tag) mice and three cell lines derived from double-transgenic offsprings of CEA424/Tag mice mated with human carcinoembryonic antigen (CEA)-transgenic (CEA424/TagCEA) mice (mGC2(CEA), mGC4(CEA), mGC11(CEA)). CEA424/Tag is a transgenic C57BL/6 mouse strain harboring the Tag under the control of a -424/-8 bp CEA gene promoter which leads to the development of invasive adenocarcinoma in the glandular stomach. Tumor cell lines established from CEA424/Tag- CEA mice express the well defined tumor antigen CEA under the control of its natural regulatory elements. Results: The epithelial origin of the tumor cells was proven by morphological criteria including the presence of mucin within the cells and the expression of the cell adhesion molecules EpCAM and CEACAM1. All cell lines consistently express the transgenes CEA and/or Tag and MHC class I molecules leading to their susceptibility to lysis by Tag-specific CTL in vitro. Despite the presentation of CTL-epitopes derived from the transgene products the tumor cell lines were tumorigenic when grafted into C57BL/6, CEA424/Tag or CEA424/Tag- CEA-transgenic hosts and no significant differences in tumor take and tumor growth were observed in the different hosts. Although no spontaneous tumor rejection was observed, vaccination of C57BL/6 mice with lysates from gastric carcinoma cell lines protected C57BL/6 mice from tumor challenge, demonstrating the tumorigenicity of the tumor cell lines in nontransgenic mice of the H-2(b) haplotype. Conclusion: These tumor cell lines grafted in different syngeneic hosts should prove to be very useful to optimize immunotherapy regimens to be finally tested in transgenic animals developing primary gastric carcinomas.