86 research outputs found
The homeodomain transcription factor Orthopedia is involved in development of the Drosophila hindgut
Background
The Drosophila hindgut is commonly used model for studying various aspects of organogenesis like primordium establishment, further specification, patterning, and morphogenesis. During embryonic development of Drosophila, many transcriptional activators are involved in the formation of the hindgut. The transcription factor Orthopedia (Otp), a member of the 57B homeobox gene cluster, is expressed in the hindgut and nervous system of developing Drosophila embryos, but due to the lack of mutants no functional analysis has been conducted yet.
Results
We show that two different otp transcripts, a hindgut-specific and a nervous system-specific form, are present in the Drosophila embryo. Using an Otp antibody, a detailed expression analysis during hindgut development was carried out. Otp was not only expressed in the embryonic hindgut, but also in the larval and adult hindgut. To analyse the function of otp, we generated the mutant otp allele otpGT by ends-out gene targeting. In addition, we isolated two EMS-induced otp alleles in a genetic screen for mutants of the 57B region. All three otp alleles showed embryonic lethality with a severe hindgut phenotype. Anal pads were reduced and the large intestine was completely missing. This phenotype is due to apoptosis in the hindgut primordium and the developing hindgut.
Conclusion
Our data suggest that Otp is another important factor for hindgut development of Drosophila. As a downstream factor of byn Otp is most likely present only in differentiated hindgut cells during all stages of development rather than in stem cells
Web-based audiovisual patient information system—a study of preoperative patient information in a neurosurgical department
Background: In the current climate of increasing awareness, patients are demanding more knowledge about forthcoming operations. The patient information accounts for a considerable part of the physician's daily clinical routine. Unfortunately, only a small percentage of the information is understood by the patient after solely verbal elucidation. To optimise information delivery, different auxiliary materials are used. Methods: In a prospective study, 52 consecutive stationary patients, scheduled for an elective lumbar disc operation were asked to use a web-based audiovisual patient information system. A combination of pictures, text, tone and video about the planned surgical intervention is installed on a tablet personal computer presented the day before surgery. All patients were asked to complete a questionnaire. Results: Eighty-four percent of all participants found that the audiovisual patient information system lead to a better understanding of the forthcoming operation. Eighty-two percent found that the information system was a very helpful preparation before the pre-surgical interview with the surgeon. Ninety percent of all participants considered it meaningful to provide this kind of preoperative education also to patients planned to undergo other surgical interventions. Eighty-four percent were altogether "very content” with the audiovisual patient information system and 86% would recommend the system to others. Conclusions: This new approach of patient information had a positive impact on patient education as is evident from high satisfaction scores. Because patient satisfaction with the informed consent process and understanding of the presented information improved substantially, the audiovisual patient information system clearly benefits both surgeons and patient
Functional analysis of enhancer elements regulating the expression of the Drosophila homeodomain transcription factor DRx by gene targeting
Background
The Drosophila brain is an ideal model system to study stem cells, here called neuroblasts, and the generation of neural lineages. Many transcriptional activators are involved in formation of the brain during the development of Drosophila melanogaster. The transcription factor Drosophila Retinal homeobox (DRx), a member of the 57B homeobox gene cluster, is also one of these factors for brain development.
Results
In this study a detailed expression analysis of DRx in different developmental stages was conducted. We show that DRx is expressed in the embryonic brain in the protocerebrum, in the larval brain in the DM and DL lineages, the medulla and the lobula complex and in the central complex of the adult brain. We generated a DRx enhancer trap strain by gene targeting and reintegration of Gal4, which mimics the endogenous expression of DRx. With the help of eight existing enhancer-Gal4 strains and one made by our group, we mapped various enhancers necessary for the expression of DRx during all stages of brain development from the embryo to the adult. We made an analysis of some larger enhancer regions by gene targeting. Deletion of three of these enhancers showing the most prominent expression patterns in the brain resulted in specific temporal and spatial loss of DRx expression in defined brain structures.
Conclusion
Our data show that DRx is expressed in specific neuroblasts and defined neural lineages and suggest that DRx is another important factor for Drosophila brain development
Regulatory modules mediating the complex neural expression patterns of the homeobrain gene during Drosophila brain development
Background: The homeobox gene homeobrain (hbn) is located in the 57B region together with two other homeobox genes, Drosophila Retinal homeobox (DRx) and orthopedia (otp). All three genes encode transcription factors with
important functions in brain development. Hbn mutants are embryonic lethal and characterized by a reduction in the
anterior protocerebrum, including the mushroom bodies, and a loss of the supraoesophageal brain commissure.
Results: In this study we conducted a detailed expression analysis of Hbn in later developmental stages. In the larval
brain, Hbn is expressed in all type II lineages and the optic lobes, including the medulla and lobula plug. The gene is
expressed in the cortex of the medulla and the lobula rim in the adult brain. We generated a new hbnKOGal4 enhancer
trap strain by reintegrating Gal4 in the hbn locus through gene targeting, which refects the complete hbn expression during development. Eight diferent enhancer-Gal4 strains covering 12 kb upstream of hbn, the two large introns
and 5 kb downstream of the gene, were established and hbn expression was investigated. We characterized several
enhancers that drive expression in specifc areas of the brain throughout development, from embryo to the adulthood. Finally, we generated deletions of four of these enhancer regions through gene targeting and analysed their
efects on the expression and function of hbn.
Conclusion: The complex expression of Hbn in the developing brain is regulated by several specifc enhancers
within the hbn locus. Each enhancer fragment drives hbn expression in several specifc cell lineages, and with largely
overlapping patterns, suggesting the presence of shadow enhancers and enhancer redundancy. Specifc enhancer
deletion strains generated by gene targeting display developmental defects in the brain. This analysis opens an
avenue for a deeper analysis of hbn regulatory elements in the future
The Reverse Transcription Signature of N-\u3csub\u3e1\u3c/sub\u3e-Methyladenosine in RNA-Seq is Sequence Dependent
The combination of Reverse Transcription (RT) and high-throughput sequencing has emerged as a powerful combination to detect modified nucleotides in RNA via analysis of either abortive RT-products or of the incorporation of mismatched dNTPs into cDNA. Here we simultaneously analyze both parameters in detail with respect to the occurrence of N-1-methyladenosine (m1A) in the template RNA. This naturally occurring modification is associated with structural effects, but it is also known as a mediator of antibiotic resistance in ribosomal RNA. In structural probing experiments with dimethylsulfate, m1A is routinely detected by RT-arrest. A specifically developed RNA-Seq protocol was tailored to the simultaneous analysis of RT-arrest and misincorporation patterns. By application to a variety of native and synthetic RNA preparations, we found a characteristic signature of m1A, which, in addition to an arrest rate, features misincorporation as a significant component. Detailed analysis suggests that the signature depends on RNA structure and on the nature of the nucleotide 3’ of m1A in the template RNA, meaning it is sequence dependent. The RT-signature ofm1Awas used for inspection and confirmation of suspected modification sites and resulted in the identification of hitherto unknown m1A residues in trypanosomal tRNA
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Simultaneous Effect of Ultraviolet Radiation and Surface Modification on the Work Function and Hole Injection Properties of ZnO Thin Films
The combined effect of ultraviolet (UV) light soaking and self-assembled monolayer deposition on the work function (WF) of thin ZnO layers and on the efficiency of hole injection into the prototypical conjugated polymer poly(3-hexylthiophen-2,5-diyl) (P3HT) is systematically investigated. It is shown that the WF and injection efficiency depend strongly on the history of UV light exposure. Proper treatment of the ZnO layer enables ohmic hole injection into P3HT, demonstrating ZnO as a potential anode material for organic optoelectronic devices. The results also suggest that valid conclusions on the energy-level alignment at the ZnO/organic interfaces may only be drawn if the illumination history is precisely known and controlled. This is inherently problematic when comparing electronic data from ultraviolet photoelectron spectroscopy (UPS) measurements carried out under different or ill-defined illumination conditions. © 2020 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinhei
Simultaneous Effect of Ultraviolet Radiation and Surface Modification on the Work Function and Hole Injection Properties of ZnO Thin Films
The combined effect of ultraviolet (UV) light soaking and self-assembled monolayer deposition on the work function (WF) of thin ZnO layers and on the efficiency of hole injection into the prototypical conjugated polymer poly(3-hexylthiophen-2,5-diyl) (P3HT) is systematically investigated. It is shown that the WF and injection efficiency depend strongly on the history of UV light exposure. Proper treatment of the ZnO layer enables ohmic hole injection into P3HT, demonstrating ZnO as a potential anode material for organic optoelectronic devices. The results also suggest that valid conclusions on the energy-level alignment at the ZnO/organic interfaces may only be drawn if the illumination history is precisely known and controlled. This is inherently problematic when comparing electronic data from ultraviolet photoelectron spectroscopy (UPS) measurements carried out under different or ill-defined illumination conditions.Deutsche Forschungsgemeinschaft
http://dx.doi.org/10.13039/501100001659Peer Reviewe
Total Neoadjuvant Therapy for Rectal Cancer in the CAO/ARO/AIO-12 Randomized Phase 2 Trial: Early Surrogate Endpoints Revisited
Background: Early efficacy outcome measures in rectal cancer after total neoadjuvant
treatment are increasingly investigated. We examined the prognostic role of pathological complete
response (pCR), tumor regression grading (TRG) and neoadjuvant rectal (NAR) score for disease-free
survival (DFS) in patients with rectal carcinoma treated within the CAO/ARO/AIO-12 randomized
phase 2 trial. Methods: Distribution of pCR, TRG and NAR score was analyzed using the Pearson’s
chi-squared test. Univariable analyses were performed using the log-rank test, stratified by treatment
arm. Discrimination ability of non-pCR for DFS was assessed by analyzing the ROC curve as a
function of time. Results: Of the 311 patients enrolled, 306 patients were evaluable (Arm A:156, ArmB:150). After a median follow-up of 43 months, the 3-year DFS was 73% in both groups (HR, 0.95,
95% CI, 0.63–1.45, p = 0.82). pCR tended to be higher in Arm B (17% vs. 25%, p = 0.086). In both
treatment arms, pCR, TRG and NAR were significant prognostic factors for DFS, whereas survival
in subgroups defined by pCR, TRG or NAR did not significantly differ between the treatment arms.
The discrimination ability of non-pCR for DFS remained constant over time (C-Index 0.58) but was
slightly better in Arm B (0.61 vs. 0.56). Conclusion: Although pCR, TRG and NAR were strong
prognostic factors for DFS in the CAO/ARO/AIO-12 trial, their value in selecting one TNT approach
over another could not be confirmed. Hence, the conclusion of a long-term survival benefit of one
treatment arm based on early surrogate endpoints should be stated with caution
Are fear-avoidance beliefs in low back pain patients a risk factor for low physical activity or vice versa? A cross-lagged panel analysis
Objective: The assumption that low back pain (LBP) patients suffer from “disuse” as a consequence of high fear-avoidance beliefs is currently under debate. A secondary analysis served to investigate whether fear-avoidance beliefs are associated cross-sectionally and longitudinally with the physical activity level (PAL) in LBP patients
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