The effect of preoperative stoma site marking on risk of stoma-related complications in patients with intestinal ostomy - A systematic review and meta-analysis.

AIM: This systematic review and meta-analysis aimed to investigate the effect of preoperative stoma site marking on stoma-related complications in patients with intestinal ostomy. METHODS: MEDLINE, Embase, CENTRAL, CINHAL, and Google Scholar were searched up to August 2021 for randomised controlled trials (RCTs) and nonrandomised studies of interventions (NRSI) that involved patients with intestinal ostomies comparing preoperative stoma site marking to no marking and which reported at least one patient-relevant outcome. Outcomes were prioritised by stakeholder involvement. Random-effects meta-analyses produced odds ratios (ORs) or standardised mean differences (SMD) and 95% confidence intervals (CIs). The ROBINS-I tool and the GRADE approach were used to assess the risk of bias and certainty of evidence, respectively. RESULTS: This review included two RCTs and 25 NRSI. The risk of bias was high in RCTs and serious to critical in NRSI. Although preoperative site marking reduced stoma-related complications (OR: 0.45, 95% CI: [0.31-0.65]), dependence on professional or unprofessional care (narrative synthesis), and increased health-related quality of life (SMD: 1.13 [0.38-1.88]), the evidence is very uncertain. Preoperative site marking may probably reduce leakage (OR: 0.14 [0.06-0.37]) and may decrease dermatological complications (OR: 0.38 [0.29-0.50]) and surgical revision (OR: 0.09 [0.02-0.49]). The confidence in the cumulative evidence was moderate to very low. CONCLUSION: Despite low quality evidence, preoperative stoma site marking can prevent stoma-related complications and should be performed in patients undergoing gastrointestinal surgery given that this intervention poses no harm to patients.

Attitude toward second opinions in Germany - a survey of the general population.

BACKGROUND: Second medical opinions (SOs) can assist patients in making informed treatment decisions and improve the understanding of their diagnosis. In Germany, there are different approaches to obtain a structured SO procedure: SO programs by health insurers and SOs according to the SO Directive. Through a direct survey of the population, we aimed to assess how structured SOs should be provided to fulfil patients' needs. METHODS: A stratified sample of 9990 adults (≥18 years) living in the federal states of Berlin and Brandenburg (Germany) were initially contacted by post in April and sent a reminder in May 2020. The survey results were analyzed descriptively. RESULTS: Among 1349 participants (response rate 14%), 56% were female and the median age was 58 years (interquartile range (IQR) 44-69). Participants wanted to be informed directly and personally about the possibility of obtaining an SO (89%; 1201/1349). They preferred to be informed by their physician (93%; 1249/1349). A majority of participants would consider it important to obtain an SO for oncological indications (78%; 1049/1349). Only a subset of the participants would seek an SO via their health insurer or via an online portal (43%; 577/1349 and 16%; 221/1349). A personally delivered SO was the preferred route of SO delivery, as 97% (1305/1349) would (tend to) consider this way of obtaining an SO. Participants were asked to imagine having moderate knee pain for years, resulting in a treatment recommendation for knee joint replacement. They were requested to rate potential qualification criteria for a physician providing the SO. The criteria rated to be most important were experience with the recommended diagnosis/treatment (criterion (very) important for 93%; 1257/1349) and knowledge of the current state of research (criterion (very) important for 86%; 1158/1349). Participants were willing to travel 60 min (median; IQR 60-120) and wait 4 weeks (median; IQR 2-4) for their SO in the hypothetical case of knee pain. CONCLUSION: In general, SOs were viewed positively. We found that participants have clear preferences regarding SOs. We propose that these preferences should be taken into account in the future design and development of SO programs.

The effect of preoperative stoma site marking on risk of stoma-related complications in patients with intestinal ostomy-protocol of a systematic review and meta-analysis.

BACKGROUND: An intestinal ostomy is an artificial bowel opening created on the skin. Procedure-related mortality is extremely rare. However, the presence of an ostomy may be associated with significant morbidity. Complications negatively affect the quality of life of ostomates. Preoperative stoma site marking can reduce stoma-related complications and is recommended by several guidelines. However, there is no consensus on the procedure and recommendations are based on low-quality evidence. The objective of the systematic review will be to investigate if preoperative stoma site marking compared to no preoperative marking in patients undergoing intestinal stoma surgery reduces or prevents the rate of stoma-related complications. METHODS: We will include (cluster-) randomised controlled trials and cohort studies that involve patients with intestinal ostomies comparing preoperative stoma site marking to no preoperative marking and report at least one patient-relevant outcome. For study identification, we will systematically search MEDLINE/PubMed, EMBASE, CENTRAL and CINHAL as well as Google Scholar, trial registries, conference proceedings and reference lists. Additionally, we will contact experts in the field. Two reviewers will independently perform study selection and data extraction. Outcomes will be prioritised based on findings from telephone interviews with five ostomates and five ostomy and wound nurses prior to conducting the review. Outcomes may include but are not limited to stoma-related complications (infection, parastomal abscess, hernia, mucocutaneous separation, dermatological complications, stoma necrosis, stenosis, retraction and prolapse) or other patient-relevant postoperative endpoints (quality of life, revision rate, dependence on professional care, mortality, length of stay and readmission). We will use the ROBINS-I or the Cochrane risk of bias tool to assess the risk of bias of the included studies. We will perform a meta-analysis and assess the certainty of evidence using the GRADE approach. DISCUSSION: With the results of the systematic review, we aim to provide information for future clinical guidelines and influence clinical routine with regard to preoperative stoma site marking in patients undergoing ostomy surgery. When the evidence of our systematic review is low, it would still be a useful basis for future clinical trials by identifying data gaps. SYSTEMATIC REVIEW REGISTRATION: PROSPERO registration number: CRD42021226647.

Analysis of second opinion programs provided by German statutory and private health insurance - a survey of statutory and private health insurers.

BACKGROUND: Second medical opinions can give patients confidence when choosing among treatment options and help them understand their diagnosis. Health insurers in several countries, including Germany, offer formal second opinion programs (SecOPs). We systematically collected and analyzed information on German health insurers' approach to SecOPs, how the SecOPs are structured, and to what extent they are evaluated. METHODS: In April 2019, we sent a questionnaire by post to all German statutory (n = 109) and private health insurers (n = 52). In September 2019, we contacted the nonresponders by email. The results were analyzed descriptively. They are presented overall and grouped by type of insurance (statutory/private health insurer). RESULTS: Thirty one of One hundred sixty one health insurers (response rate 19%) agreed to participate. The participating insurers covered approximately 40% of the statutory and 34% of the private health insured people. A total of 44 SecOPs were identified with a median of 1 SecOP (interquartile range (IQR) 1-2) offered by a health insurer. SecOPs were in place mainly for orthopedic (21/28 insurers with SecOPs; 75%) and oncologic indications (20/28; 71%). Indications were chosen principally based on their potential impact on a patient (22/28; 79%). The key qualification criterion for second opinion providers was their expertise (30/44 SecOPs; 68%). Second opinions were usually provided based on submitted documents only (21/44; 48%) or on direct contact between a patient and a doctor (20/44; 45%). They were delivered after a median of 9 days (IQR 5-15). A median of 31 (IQR 7-85) insured persons per year used SecOPs. Only 12 of 44 SecOPs were confirmed to have conducted a formal evaluation process (27%) or, if not, plan such a process in the future (10/22; 45%). CONCLUSION: Health insurers' SecOPs focus on orthopedic and oncologic indications and are based on submitted documents or on direct patient-physician contact. The formal evaluation of SecOPs needs to be expanded and the results should be published. This can allow the evaluation of the impact of SecOPs on insured persons' health status and satisfaction, as well as on the number of interventions performed. Our results should be interpreted with caution due to the low participation rate.

Hospital volume-outcome relationship in total knee arthroplasty: protocol for a systematic review and non-linear dose-response meta-analysis.

BACKGROUND: Knee osteoarthritis is a common, chronic condition and main contributor to global disability. Total knee arthroplasty (TKA) is the most successful treatment for end-stage knee osteoarthritis. It is assumed that in the field of surgery, there is a relationship between hospital volume and health outcomes and that higher hospital volume results in better health outcomes. As a consequence, minimum volume thresholds have been implemented in Germany for various procedures, including TKA (50 procedures per year). To date, it is unclear whether minimum volume thresholds truly result in better outcomes. The objective of this study will be to quantify the relationship between hospital volume and patient-relevant outcomes in patients undergoing TKA. METHODS: We will include published or unpublished (cluster-) randomized controlled trials and prospective or retrospective cohort studies that involve patients with primary and/or revision TKA, report at least two different hospital volumes and report at least one patient-relevant outcome. To identify studies, we will systematically search (from inception onwards) PubMed/MEDLINE, Embase, CENTRAL, and CINAHL, as well as trial registers, conference proceedings, and reference lists. We will also contact experts in the field. Study selection and data extraction will be performed by two reviewers independently. The primary outcome will be rate of early revision. Secondary outcomes will include rate of revision > 1 year, mortality, length of stay, readmission rate, surgical complications, adverse events and health-related quality of life. We will assess the risk of bias of the included studies using ROBINS-I or the Cochrane risk of bias tool. Both a linear and a non-linear dose-response meta-analyses will be performed. We will use the GRADE approach to evaluate our confidence in the cumulative evidence. We will incorporate patients' needs, goals and preferences into our recommendations by consulting three focus groups, each consisting of eight participants. DISCUSSION: The findings of our systematic review will probably be limited by the design of the included studies. We do not expect to identify any (cluster-) randomized controlled trials that meet our inclusion criteria. Therefore, the best available evidence included in our systematic review will most likely consist of cohort studies only. We anticipate that the results of this study will inform future health policy decisions in Germany regarding the minimum volume threshold for TKA. Systematic review registration: PROSPERO CRD42019131209.

Inter-review agreement of risk-of-bias judgments varied in Cochrane reviews.

OBJECTIVES: The objective of the study was to measure the level of agreement between Cochrane reviews of overlapping randomized controlled trials (RCTs) regarding risk-of-bias (RoB) judgments. STUDY DESIGN AND SETTING: On November 5, 2017, the Cochrane Database of Systematic Reviews was searched for Cochrane reviews on tobacco. Reviews that included overlapping RCTs were included. RoB judgments were extracted from RoB tables using automated data scraping with manual verification and adjustments. Agreement between the reviews was calculated using Conger's generalized kappa coefficient (κ) and raw agreement (a). RESULTS: We included 53 Cochrane reviews of 376 RCTs. For the RoB domain "random sequence generation," the level of agreement between the reviews was substantial with κ = 0.63 (95% confidence interval: 0.56 to 0.71; a = 0.80). There was slight-to-moderate agreement between the reviews regarding the domains "allocation concealment": κ = 0.51 (0.41 to 0.61), a = 0.75; "blinding": κ = 0.19 (0.02 to 0.37), a = 0.52; "blinding of outcome assessment": κ = 0.43 (0.14 to 0.72) a = 0.67; and "incomplete outcome data": κ = 0.15 (-0.03 to 0.32), a = 0.64. For "blinding of participants and personnel" and "selective reporting", κ could not be calculated. The raw agreement was 0.40 and 0.42, respectively. CONCLUSION: The level of agreement between Cochrane reviews regarding RoB judgments ranged from slight to substantial depending on the RoB domain. Further investigations regarding reasons for variation and interventions to improve agreement are needed.

[Compilation of Second Opinion Programs in the German Statutory Health Insurance]. / Bestandsaufnahme zu Zweitmeinungsverfahren in der Gesetzlichen Krankenversicherung (GKV).

OBJECTIVE: According to a new legislation passed in 2016, patients with an indication for elective procedures have the right to obtain a second opinion. The Federal Joint Committee has not yet provided a list of indications that this legislation will cover. Independently of this, the statutory health insurances can, nonetheless, pay for a second opinion. The aim of this article is to give an overview of current second opinion programs delivered by the statutory health insurance schemes. METHODS: Websites of all German statutory health insurance schemes (n=117) were searched for second opinion programs and their features in November 2016. All data was extracted by one person and verified by a second person. RESULTS: In total, 78 second-opinion programs were identified. Half of all statutory health insurance schemes (50%, n=59) provide at least one second-opinion program. The majority of them was in the field of orthopedics (78%, n=61) and oncology (58%, n=45). Multiple replies were possible. In most cases, second-opinion programs were outsourced (58%; n=44), followed by forwarding patients to health service providers contracted with the statutory health insurance scheme (45% n=34). Only in 11% (n=8) was the second opinion delivered by staff of the statutory health insurance scheme. The second opinion was delivered based on submitted documents only (63%; n=48), direct patient-physician contact (43%; n=33), and contact by phone (14%; n=11). The delivery of the second opinion took 7 days in median, while the delivery based on submitted documents only (median 7) was faster than the delivery by direct-physician contact (median 14). CONCLUSIONS: The majority of those living in Germany have the possibility to obtain a second opinion. However, second-opinion programs are very heterogeneous so that patients are confused about their rights to second opinion.

Fatores associados à síndrome metabólica em adultos atendidos em um ambulatório de nutrição / Factors associated with metabolic syndrome in adults attending a nutrition outpatient clinic

Objetivos: Estudar os fatores associados à síndrome metabólica em pacientes adultos atendidos em um ambulatório de nutrição.Métodos: Um estudo transversal incluiu pacientes de 18 a 59 anos de idade, de ambos os sexos, encaminhados para atendimento no Ambulatório de Nutrição da Secretaria de Saúde da Prefeitura Municipal de Portão, estado do Rio Grande do Sul. Foram coletadas informações sociodemográficas e comportamentais através de questionários estruturados, padronizados e pré-codificados. Para avaliação do estado nutricional e da obesidade abdominal foram realizadas medidas antropométricas. O diagnóstico da síndrome metabólica foi realizado de acordo com as recomendações do Harmonizing the Metabolic Syndrome.Resultados: Foram estudados 156 pacientes, sendo 119 (84,3%) mulheres e 37 (17,7%) homens. A prevalência de síndrome metabólica foi 54,7% e o componente mais frequentemente alterado foi a circunferência da cintura (88,6%). A presença da síndrome metabólica esteve associada diretamente à idade, sendo sua prevalência de 75% entre os indivíduos com idade maior ou igual a 52 anos; inversamente à escolaridade, com prevalência de 64,5% em pessoas com escolaridade menor ou igual a quatro anos; associada ao tabagismo, observando-se maior prevalência entre os ex-fumantes (69,8%); e ao estado nutricional, evidenciando-se um maior percentual (75%) entre os indivíduos com maior índice de massa corporal.Conclusões: O estudo revelou uma elevada prevalência de síndrome metabólica nos adultos que demandam atendimento nutricional. A presença da síndrome metabólica esteve associada à maior idade, menor escolaridade, tabagismo e maior índice de massa corporal...

AIMS: To investigate factors associated with metabolic syndrome in adult patients seen in an outpatient nutrition clinic.METHODS: A cross-sectional study included patients with 18-59 years of age, of both sexes, referred for care at the Outpatient Nutrition Department of the Health Secretary of the City of Port�o, Rio Grande do Sul state. Sociodemographic and behavioral data were collected through structured, standardized, pre-coded questionnaires. Anthropometric measurements were performed to assess nutritional status and abdominal obesity. The diagnosis of metabolic syndrome was conducted in accordance with the recommendations of "Harmonizing the Metabolic Syndrome".RESULTS: A total of 156 patients were studied, 119 (84.3 %) women and 37 (17.7%) men. The prevalence of metabolic syndrome was 54.7 % and the component most often altered was waist circumference (88.6%). The presence of metabolic syndrome was directly associated with age, with a prevalence of 75 % among individuals aged 52 years or more; inversely associated to schooling, with a prevalence of 64.5% in those with less than or equal to four years of education; associated with smoking, with a higher prevalence among former smokers (69.8%); and with nutritional status, evidencing a higher percentage (75 %) among individuals with higher body mass index.CONCLUSIONS: The study revealed a high prevalence of metabolic syndrome in adults requiring nutrition assistance. The presence of metabolic syndrome was associated with higher age, lower education, smoking, and higher body mass index...

Evaluation of cytopathology fellow performance for rapid on-site evaluations of fine-needle aspirates over a 6-year period.

INTRODUCTION: Rapid on-site evaluation (ROSE) of fine-needle aspirates is an invaluable teaching tool for a cytopathology (CyP) fellowship. The ability of fellows to accurately perform ROSEs without direct attending supervision is not well documented in the literature. This study reviewed ROSEs performed independently by CyP fellows and focused on diagnostic discrepancies with managerial implications. MATERIAL AND METHODS: All fine-needle aspirates with ROSE documentation performed at the University of Virginia from October 1, 2007 to March 31, 2013 were reviewed and compared with the final diagnosis. Cases were only included if a CyP fellow performed the ROSE. Discrepancy between ROSE and final diagnosis was categorized according to the change. Numbers of false positive (FP) and false negative diagnoses, organ site, and recurrent interpretative pitfalls were noted. RESULTS: CyP fellows performed 6815 ROSEs in 6 years. An attending cytopathologist was present 8% of the time. Of ROSEs without direct attending supervision (6224 fine-needle aspirates), the preliminary and final diagnoses were identical in 95% of cases. FP rate was 1.06%. The most frequent categorical change occurred from ROSE of "atypical" to final diagnosis of "malignant." The most common sites involved in FP diagnoses were pancreas/biliary tract, lung, and lymph node. Experience gained over the fellowship year did not significantly affect the FP rate. Errors encountered are known interpretative challenges. CONCLUSIONS: This is the largest study addressing discrepancies between ROSE and final diagnosis and the first study examining CyP fellow performance. Our results affirm that fellows perform extremely well when performing ROSEs independently.

A loss-of-function screen reveals Ras- and Raf-independent MEK-ERK signaling during Chlamydia trachomatis infection.

Chlamydiae are obligate intracellular bacterial pathogens that have a major effect on human health. Because of their intimate association with their host, chlamydiae depend on various host cell functions for their survival. Here, we present an RNA-interference-based screen in human epithelial cells that identified 59 host factors that either positively or negatively influenced the replication of Chlamydia trachomatis (Ctr). Two factors, K-Ras and Raf-1, which are members of the canonical Ras-Raf-MEK (mitogen-activated or extracellular signal-regulated protein kinase kinase)-ERK (extracellular signal-regulated kinase) pathway, were identified as central components of signaling networks associated with hits from the screen. Depletion of Ras or Raf in HeLa cells increased pathogen growth. Mechanistic analyses revealed that ERK was activated independently of K-Ras and Raf-1. Infection with Ctr led to the Akt-dependent, increased phosphorylation (and inactivation) of Raf-1 at serine-259. Furthermore, phosphorylated Raf-1 relocalized from the cytoplasm to the intracellular bacterial inclusion in an Akt- and 14-3-3beta-dependent manner. Together, these findings not only show that Chlamydia regulates components of an important host cell signaling pathway, but also provide mechanistic insights into how this is achieved.

High-throughput and single-cell imaging of NF-kappaB oscillations using monoclonal cell lines.

BACKGROUND: The nuclear factor-kappaB (NF-kappaB) family of transcription factors plays a role in a wide range of cellular processes including the immune response and cellular growth. In addition, deregulation of the NF-kappaB system has been associated with a number of disease states, including cancer. Therefore, insight into the regulation of NF-kappaB activation has crucial medical relevance, holding promise for novel drug target discovery. Transcription of NF-kappaB-induced genes is regulated by differential dynamics of single NF-kappaB subunits, but only a few methods are currently being applied to study dynamics. In particular, while oscillations of NF-kappaB activation have been observed in response to the cytokine tumor necrosis factor alpha (TNFalpha), little is known about the occurrence of oscillations in response to bacterial infections. RESULTS: To quantitatively assess NF-kappaB dynamics we generated human and murine monoclonal cell lines that stably express the NF-kappaB subunit p65 fused to GFP. Furthermore, a high-throughput assay based on automated microscopy coupled to image analysis to quantify p65-nuclear translocation was established. Using this assay, we demonstrate a stimulus- and cell line-specific temporal control of p65 translocation, revealing, for the first time, oscillations of p65 translocation in response to bacterial infection. Oscillations were detected at the single-cell level using real-time microscopy as well as at the population level using high-throughput image analysis. In addition, mathematical modeling of NF-kappaB dynamics during bacterial infections predicted masking of oscillations on the population level in asynchronous activations, which was experimentally confirmed. CONCLUSIONS: Taken together, this simple and cost effective assay constitutes an integrated approach to infer the dynamics of NF-kappaB kinetics in single cells and cell populations. Using a single system, novel factors modulating NF-kappaB can be identified and analyzed, providing new possibilities for a wide range of applications from therapeutic discovery and understanding of disease to host-pathogen interactions.

Genome-wide RNAi screen identifies human host factors crucial for influenza virus replication.

Influenza A virus, being responsible for seasonal epidemics and reoccurring pandemics, represents a worldwide threat to public health. High mutation rates facilitate the generation of viral escape mutants, rendering vaccines and drugs directed against virus-encoded targets potentially ineffective. In contrast, targeting host cell determinants temporarily dispensable for the host but crucial for virus replication could prevent viral escape. Here we report the discovery of 287 human host cell genes influencing influenza A virus replication in a genome-wide RNA interference (RNAi) screen. Using an independent assay we confirmed 168 hits (59%) inhibiting either the endemic H1N1 (119 hits) or the current pandemic swine-origin (121 hits) influenza A virus strains, with an overlap of 60%. Notably, a subset of these common hits was also essential for replication of a highly pathogenic avian H5N1 strain. In-depth analyses of several factors provided insights into their infection stage relevance. Notably, SON DNA binding protein (SON) was found to be important for normal trafficking of influenza virions to late endosomes early in infection. We also show that a small molecule inhibitor of CDC-like kinase 1 (CLK1) reduces influenza virus replication by more than two orders of magnitude, an effect connected with impaired splicing of the viral M2 messenger RNA. Furthermore, influenza-virus-infected p27(-/-) (cyclin-dependent kinase inhibitor 1B; Cdkn1b) mice accumulated significantly lower viral titres in the lung, providing in vivo evidence for the importance of this gene. Thus, our results highlight the potency of genome-wide RNAi screening for the dissection of virus-host interactions and the identification of drug targets for a broad range of influenza viruses.

Cystic fibrosis transmembrane conductance regulator mutations in azoospermic and oligospermic men and their partners.

The objective of this study was to investigate the contribution of cystic fibrosis transmembrane conductance regulator (CFTR) to human infertility and to define screening and counselling procedures for couples asking for assisted reproduction treatment. Extended CFTR mutation screening was performed in 310 infertile men (25 with congenital absence of the vas deferens (CAVD), 116 with non-CAVD azoospermia, 169 with severe oligospermia), 70 female partners and 96 healthy controls. CFTR mutations were detected in the majority (68%) of CAVD patients and in significant proportions in azoospermic (31%) and oligospermic (22%) men. Carrier frequency among partners of infertile men was 16/70, exceeding that of controls (6/96) significantly (P = 0.0005). Thus, in 23% of infertile couples both partners were carriers, increasing the risk for their offspring to inherit two mutations to 25% or 50%. This study emphasizes the necessity to offer extended CFTR mutation screening and counselling not only to patients with CAVD but also to azoospermic and oligozoospermic men and their partners before undergoing assisted reproduction techniques. The identification of rare and/or mild mutations will not be a reason to abstain from parenthood, but will allow adequate treatment in children at risk for atypical or mild cystic fibrosis as soon as they develop any symptoms.

A large-scale chemical modification screen identifies design rules to generate siRNAs with high activity, high stability and low toxicity.

The use of chemically synthesized short interfering RNAs (siRNAs) is currently the method of choice to manipulate gene expression in mammalian cell culture, yet improvements of siRNA design is expectably required for successful application in vivo. Several studies have aimed at improving siRNA performance through the introduction of chemical modifications but a direct comparison of these results is difficult. We have directly compared the effect of 21 types of chemical modifications on siRNA activity and toxicity in a total of 2160 siRNA duplexes. We demonstrate that siRNA activity is primarily enhanced by favouring the incorporation of the intended antisense strand during RNA-induced silencing complex (RISC) loading by modulation of siRNA thermodynamic asymmetry and engineering of siRNA 3'-overhangs. Collectively, our results provide unique insights into the tolerance for chemical modifications and provide a simple guide to successful chemical modification of siRNAs with improved activity, stability and low toxicity.

Complex kinase requirements for Chlamydia trachomatis Tarp phosphorylation.

Chlamydia trachomatis translocates the effector protein Tarp (translocated actin-recruiting phosphoprotein) into the host cell cytoplasm where it is quickly tyrosine phosphorylated. Abl and Src kinases have been implicated in Tarp phosphorylation; however, we observed that the situation is more complex. Chemical inhibition of Src family kinases confirmed a role for these kinases in Tarp phosphorylation. Infection of Src, Yes, Fyn (SYF)-deficient cells showed a dampened, but incompletely blocked, Tarp phosphorylation. Inhibition of Abl in an SYF background still did not completely block Tarp phosphorylation. Consequently, we tested additional kinases and found that Syk, but not Btk or Jak2, is a potent kinase of Tarp in vitro. Inhibition of Syk in an SYF background further blocked Tarp phosphorylation. Under these conditions, inclusion formation still proceeded normally. These data reveal a highly promiscuous substrate property of Tarp and set the stage for further functional characterization of Tarp phosphorylation during host cell infection.

Prion protein/protein interactions: fusion with yeast Sup35p-NM modulates cytosolic PrP aggregation in mammalian cells.

In mammalian prion diseases, an abnormally folded, aggregated form of the prion protein (PrP(Sc)) appears to catalyze a conformational switch of its cellular isoform (PrP(C)) to an aggregated state. A similar prion-like phenomenon has been reported for the Saccharomyces cerevisiae translation termination factor Sup35p that can adopt a self-propagating conformation. We have compared aggregation propensities of chimeric proteins derived from the Sup35p prion domain NM and PrP in vitro and in the cytosol of mammalian cells. Sup35p-NM and PrP displayed strikingly different aggregation behaviors when expressed in mammalian cells, with NM remaining soluble and cytosolic PrP spontaneously aggregating due to the globular domain of PrP. When fused to PrP(90-230), Sup35p-M exhibited an inhibitory effect for nucleation but increased aggregate growth, potentially by facilitating recruitment of newly synthesized chimeric proteins into the growing aggregates. This effect, however, could, to some extent, be counteracted by the prion-forming region Sup35p-N, thereby increasing aggregate frequency. Interestingly, a lowered nucleation rate was also observed in the presence of the amino-terminal region of PrP, suggesting that Sup35p-M and PrP(23-90) share some biological function in prion protein assembly. Our results provide new insights into prion protein aggregation behaviors, demonstrating the impact of dynamic interactions between prion domains and suggesting that aggregation of yeast and mammalian prion proteins is strongly influenced by yet unidentified cellular conditions or factors.

Effect of oculopharyngeal muscular dystrophy-associated extension of seven alanines on the fibrillation properties of the N-terminal domain of PABPN1.

Oculopharyngeal muscular dystrophy (OPMD) is an autosomal dominant disease that usually manifests itself within the fifth decade. The most prominent symptoms are progressive ptosis, dysphagia, and proximal limb muscle weakness. The disorder is caused by trinucleotide (GCG) expansions in the N-terminal part of the poly(A)-binding protein 1 (PABPN1) that result in the extension of a 10-alanine segment by up to seven more alanines. In patients, biopsy material displays intranuclear inclusions consisting primarily of PABPN1. Poly l-alanine-dependent fibril formation was studied using the recombinant N-terminal domain of PABPN1. In the case of the protein fragment with the expanded poly l-alanine sequence [N-(+7)Ala], fibril formation could be induced by low amounts of fragmented fibrils serving as seeds. Besides homologous seeds, seeds derived from fibrils of the wild-type fragment (N-WT) also accelerated fibril formation of N-(+7)Ala in a concentration-dependent manner. Seed-induced fibrillation of N-WT was considerably slower than that of N-(+7)Ala. Using atomic force microscopy, differences in fibril morphologies between N-WT and N-(+7)Ala were detected. Furthermore, fibrils of N-WT showed a lower resistance against solubilization with the chaotropic agent guanidinium thiocyanate than those from N-(+7)Ala. Our data clearly reveal biophysical differences between fibrils of the two variants that are likely caused by divergent fibril structures.

Neural differentiation of embryonic stem cells is induced by signalling from non-neural niche cells.

BACKGROUND/AIMS: Embryonic stem cell (ESC) transplantation offers new therapeutic strategies for neurodegenerative diseases and injury. However, the mechanisms underlying integration and differentiation of engrafted ESCs are poorly understood. This study elucidates the influence of exogenous signals on ESC differentiation using in vitro modelling of non-stem/stem cell interactions. METHODS: Murine ESCs were co-cultured with endothelial cells and astrocytes or conditioned medium obtained from endothelial or astrocyte cultures. After 7 days of co-culture isolated RNA was analysed using RT-PCR for the expression of pluripotency marker oct-4, neural progenitor marker nestin, and neurofilament (NFL), an early marker of neuronal lineage commitment. The presence of the glial cell surface marker A2B5 was determined in ESCs by flow cytometry. RESULTS: Neuronal differentiation was inhibited in ESCs when grown in close vicinity to cerebral endothelial or glial cells. Under these conditions, ESC differentiation was predominantly directed towards a glial fate. However, treatment of ESCs with endothelial cell- or astrocyte-conditioned medium promoted neuronal as well as glial differentiation. CONCLUSION: Our results indicate that ESC fate is determined by endothelial and glial cells that comprise the environmental niche of these stem cells in vivo. The direction of differentiation processes appears to be dependent on humoral factors secreted by adjacent cell lines.

Silencing or permanent activation: host-cell responses in models of persistent Chlamydia pneumoniae infection.

Chlamydia pneumoniae causes respiratory infections. In chronic diseases associated with Chlamydia, such as arteriosclerosis, C. pneumoniae is present in a persistent form, which might participate in pathogenesis of chronic inflammatory disease. To elucidate how these intracellular bacteria modulate host-cells during persistence, we compared the expression pattern of a range of host genes after short (24 h) and long (up to 7 days) times of chlamydia infection in HeLa-cells. One day post infection, in three cell-culture models of persistence, namely treatment with penicillin or IFN-gamma, or iron-depletion, infection induced the genes of CTGF, IL-6, IL-8, IL-11, LIF, EGR-1 and ETV4 in a similar fashion. However, after a longer time, two modes of host-cell reaction emerged that were dependent on the persistence model used. After IFN-gamma and penicillin treatment chlamydia-induced host-cell gene expression was inhibited, while it stayed upregulated in iron-depletion. Human monocytes/macrophages, in which persistence naturally occurs, were additionally investigated: for several genes, UV-inactivated and viable chlamydia caused long-lasting upregulation. Thus, this study reveals (i) the ability of C. pneumoniae to participate in two putative pathomechanisms of persistence, silencing and permanent activation, which might represent different in vivo situations and (ii) a strong dependence on the mode of persistence induction.

Characterization of a new rat model of experimental combined neurotrauma.

Traumatic brain injury (TBI) is present in two-thirds of patients with multiple injuries and in one-third combined with injuries of the extremities. Studies on interactive effects between central and peripheral injuries are scarce due to the absence of clinically relevant models. To meet the demand for "more-hit" models, an experimental model of combined neurotrauma (CNT) incorporating a standardized TBI via lateral fluid percussion (LFP) together with a peripheral bone fracture, i.e., tibia fracture, is introduced. Sprague-Dawley rats were randomized to four experimental groups: controls (n = 10), animals with TBI (n = 30), animals with tibia fracture (n = 30), and animals with CNT (n = 30). Morphological aspects of brain and bone injury were analyzed via standard histopathological procedures and x-ray. Trauma-induced neuromotor dysfunction was assessed using a standardized neuroscore. For interactive effects between injuries, we studied the extent and temporal pattern of circulating interleukin 6 (IL-6) levels via immunoassay and callus formation at fracture sites by means of microradiography. LFP produced an ipsilateral lesion with cortical contusion, hemorrhage, mass shift, and neuronal cell loss (adjacent cortex and hippocampus CA-2/-3), along with contralateral neuromotor dysfunction. X-rays confirmed complete fractures in the middle of the bone shaft. The type of injury (P < 0.001) and time (P = 0.022) were significantly associated with increased IL-6 levels. CNT produced the highest IL-6 plasma levels with a maximum peak at 6 h after trauma (P < 0.001). Similarly, callus formation at fracture sites in CNT was significantly increased versus fracture only (P < 0,01). The CNT model mimics a variety of clinically relevant features known from human multiple injury, including TBI, and offers novel approaches for investigation of interactive mechanisms and therapeutic approaches.