Podcasts about crosslinking

Inscrições para o congresso SBOP CBE:https://www.congressosbopcbe.com.br/Neste episódio conversamos com a Dra Júlia Gomes Fernandes Polido Cabral, com Doutorado em Ciências Visuais pela UNIFESP - Ceratocone/Cirurgia de Crosslinking, Mestrado em Ciências da Saúde pelo IAMSPE/USP/SP - Alergia Ocular e Residência médica em Oftalmologia no HSPE/SP sobre ceratocone em crianças.Falamos sobre o que é ceratocone, os principais fatores de risco, as características clínicas e as particularidades da doença na criança, como realizar o diagnóstico e o acompanhamento. Também conversamos sobre as opções de tratamento em crianças e as contraindicações.

We all know that keratoconus is very highly associated with eye rubbing. But in general, the widely held belief has been that keratoconus is just associated with eye rubbing, one of multiple factors that leads to the condition. But have we gotten it wrong? Is eye rubbing not merely associated with keratoconus, but actually the sole causative factor of keratoconus? Has there been a huge blind spot in our basic understanding of keratoconus development and progression? Dr. Damien Gatinel joins the podcast.

RESGATE AGORA SEU BÔNUS DE R$ 500,00 no Propedeutics https://oftreview.ac-page.com/oftreview-propedeutics O crosslinking do colágeno corneano é um procedimento essencial no tratamento do ceratocone, com objetivo de estabilizar a ectasia. No episódio de hoje, contamos com a presença internacional do Dr. Emílio Torres-Netto, especialista em córnea e cirurgia refrativa, atuando no Elza Institute e na Universidade de Zurique, na Suíça. O grupo que o Dr. Emílio faz parte está na fronteira do conhecimento quando o assunto é crosslinking, sendo um dos principais responsáveis pelas inovações que surgiram nesse tratamento nos últimos anos. Conversamos sobre protocolos acelerados, crosslinking Epi on, crosslinking em córneas finas, protocolos customizados e até sobre a utilização do crosslinking como forma de regularizar córneas irregulares. Esse episódio foi uma verdadeira atualização em crosslinking, sendo obrigatório para todo oftalmologista com interesse em ceratocone. Não deixe de aproveitar o bônus que anunciamos no início do episódio!

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2022.10.13.512146v1?rss=1 Authors: Liu, Y., Trnka, M. J., He, L., Burlingame, A., Correia, M. A. Abstract: We have previously documented that in liver cells, the multifunctional protein scaffold p62/SQSTM1 is closely associated with I{kappa}B, an inhibitor of the transcriptional activator NF-{kappa}B. Such an intimate p62-I{kappa}Bassociation we now document leads to a marked 18-fold proteolytic I{kappa}B-stabilization, enabling its nuclear entry and termination of the NF-{kappa}B-activation cycle. In p62-/--cells, such termination is abrogated resulting in the nuclear persistence and prolonged activation of NF-{kappa}B following inflammatory stimuli. Utilizing various approaches both classic (structural deletion, site-directed mutagenesis) as well as novel (in cell chemical crosslinking), coupled with proteomic analyses, we have defined the precise structural hotspots of p62-I{kappa}B association. Accordingly, we have identified such I{kappa}B hotspots to reside around N-terminal (K38, K47 and K67) and C-terminal (K238/C239) residues in its 5th ankyrin repeat domain. These sites interact with two hotspots in p62: One in its PB-1 subdomain around K13, and the other comprised of a positively charged patch (R183/R186/K187/K189) in the intervening region between its ZZ- and TB-subdomains. APEX proximity analyses upon I{kappa}B co-transfection of cells with and without p62 have enabled the characterization of the p62 influence on I{kappa}B-protein-protein interactions. Interestingly, consistent with p62 capacity to proteolytically stabilize I{kappa}B, its presence greatly impaired I{kappa}B interactions with various 20S/26S proteasomal subunits. Furthermore, consistent with p62-interaction with I{kappa}B on an interface opposite to that of its NF-{kappa}B-interacting interface, p62 failed to significantly affect I{kappa}B-NF-{kappa}B interactions. These collective findings together with the known dynamic p62 nucleocytoplasmic shuttling, leads us to speculate that it may be involved in piggy-back nuclear transport of I{kappa}B following its NF-{kappa}B-elicited transcriptional activation and de novo synthesis, required for the termination of the NF-{kappa}B-activation cycle. Consequently, mice carrying a liver specific deletion of p62-residues 68-252 harboring its positively charged patch, reveal age-dependent enhanced liver inflammation. Our findings reveal yet another mode of p62-mediated pathophysiologically relevant regulation of NF-{kappa}B. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

It's time for another episode of

Out of the Classroom and  into the Clinic: The Real World of Corneal Cross Linking A webinar partnership  between ESCRS and HSIOIRS, bringing you world leading opinion on the latest thinking in corneal cross linking. Chaired by Béatrice Cochener Lamard and Vikentia Katsanevaki, enjoy 5 short presentations (10 mins) followed by discussion. At the end, two younger ophthalmologists present cases discussed by the faculty!  1. CXL Basic Science and standard protocol Dimitrios Kyroudis 2. Accelerated protocols Cosimo Mazzotta 3. The epithelium debate Miltos Balidis 4. Combined procedures David Touboul 5. Pack-CXL Cross linking for infection Rohit Shetty Young ophthalmologists case presentation:  1. Artemis Matsou (Greece) 2. Adrien Mahzarian

Quer saber mais sobre um dos procedimentos mais relevantes na oftalmologia? Ainda falta aquele conhecimento diferenciado sobre o procedimento? Convidamos o Dr Flavio Villela e a Dra. Verônica Bresciani pra uma conversa sobre crosslinking. As indicações, as técnicas, o que sabemos até hoje e o que ainda está por vir, tudo foi abordado! Neste episódio bastante completo suas duvidas serão sanadas!

2 interviews this week.   Paul Rosen interviews the father of cross-linking Theo Seiler (from 2016) about complications.    In the second interview, George Kymionis talks to Roberto Bellucci about current approaches to the problem of post-LASIK ectasia.

Guests: Greg Moloney, MD Mosman, Australia Rohit Shetty, MD Vice Chairman Narayana Nethralaya Eye Institute Bangalore, India

Guests: Theo Seiler, MD, PhD Head, Institute for Refractive and Ophthalmic Surgery Zurich, Switzerland David F. Chang, MD Clinical Professor of Ophthalmology University of California, San Francisco San Francisco, CA

Guests: Marcony Santhiago, MD, PhD Professor of Ophthalmology Federal University of Rio de Janeiro and the University of Sao Paulo, Brazil Warren Hill, MD East Valley Ophthalmology Mesa, AZ

Guests: Farhad Hafezi, MD, PhDProfessor and Chair of OphthalmologyUniversity of GenevaSwitzerland   Richard Davidson, MDAssociate ProfessorDepartment of OphthalmologyUniversity of Colorado School of MedicineAurora, CO

Mobile App Strategies for Crosslinking, Increasing Engagment plus more strategies for Design and Development with Sanjay Patel, CEO of mobile app strategy and development firm Perpetuating, Inc.

Guests: Zoltan Z. Nagy, MD Professor at the Department of Ophthalmology Semmelweis University Budapest, Hungary John Kanellopoulos, MD  Professor of Ophthalmology  NYU School of Medicine New York, NY Director, Laservision.gr Institute Athens, Greece

SP 138 Crosslinking

Eukaryotic nuclear transcription is carried out by three different Polymerases (Pol), Pol I, Pol II and Pol III. Among these, Pol I is dedicated to transcription of the rRNA, which is the first step of ribosome biogenesis, and cell growth is regulated during Pol I transcription initiation by the conserved factor Rrn3/TIF-IA in yeast/human. A wealth of structural information is available on Pol II and its general transcription factors (GTFs). Recently, also the architectures of Pol I and Pol III have been described by electron microscopy and the additional subunits that are specific to Pol I and Pol III have been identified as orthologs of the Pol II transcription factors TFIIF and TFIIE. Nevertheless, we still lack information about the architecture of the Pol I initiation complex and structural data is missing explaining the regulation of Pol I initiation mediated by its central transcription initiation factor Rrn3. The Rrn3 structure solved in this study reveals a unique HEAT repeat fold and indicates dimerization of Rrn3 in solution. However, the Rrn3-dimer is disrupted upon Pol I binding. The Rrn3 structure further displays a surface serine patch. Phosphorylation of this patch represses human Pol I transcription (Mayer et al, 2005; Mayer et al, 2004), and a phospho-mimetic patch mutation prevents Rrn3 binding to Pol I in vitro, and reduces S. cerevisiae cell growth and Pol I gene occupancy in vivo. This demonstrates a conserved regulation mechanism of the Pol I-Rrn3 interaction. Crosslinking indicates that Rrn3 does not only interact with Pol I subunits A43/14, but the interface further extends past the RNA exit tunnel and dock domain to AC40/19. The corresponding region of Pol II binds the Mediator head (Soutourina et al., 2011) that co-operates with TFIIB (Baek et al, 2006). Consistent with this, the Rrn3 binding partner, core factor subunit Rrn7, is predicted to be a TFIIB homologue. Taken together, our results provide the molecular basis of Rrn3-regulated Pol I initiation and cell growth and indicate a universally conserved architecture of eukaryotic transcription initiation complexes.

An interview with John Kanellopoulos, MD. Epi-on or Epi-off? Should topography-guided PRK occur before or after cross-linking? How about intracorneal rings? Are surgeons cross-linking too much tissue? What exactly is keratoconus? Drs. A. John Kanellopoulos and Theo Seiler brought together world-wide experts to discuss these questions at an International Society of Refractive Surgery symposium during the 2010 Joint Meeting in Chicago. (December 2010)

Background: Inactivation of the Fanconi anemia (FA) pathway through defects in one of 13 FA genes occurs at low frequency in various solid cancer entities among the general population. As FA pathway inactivation confers a distinct hypersensitivity towards DNA interstrand-crosslinking (ICL)-agents, FA defects represent rational targets for individualized therapeutic strategies. Except for pancreatic cancer, however, the prevalence of FA defects in gastrointestinal (GI) tumors has not yet been systematically explored. Results: A panel of GI cancer cell lines was screened for FA pathway inactivation applying FANCD2 monoubiquitination and FANCD2/RAD51 nuclear focus formation and a newly identified FA pathway-deficient cell line was functionally characterized. The hepatocellular carcinoma (HCC) line HuH-7 was defective in FANCD2 monoubiquitination and FANCD2 nuclear focus formation but proficient in RAD51 focus formation. Gene complementation studies revealed that this proximal FA pathway inactivation was attributable to defective FANCC function in HuH-7 cells. Accordingly, a homozygous inactivating FANCC nonsense mutation (c.553C > T, p.R185X) was identified in HuH-7, resulting in partial transcriptional skipping of exon 6 and leading to the classic cellular FA hypersensitivity phenotype; HuH-7 cells exhibited a strongly reduced proliferation rate and a pronounced G2 cell cycle arrest at distinctly lower concentrations of ICL-agents than a panel of non-isogenic, FA pathway-proficient HCC cell lines. Upon retroviral transduction of HuH-7 cells with FANCC cDNA, FA pathway functions were restored and ICL-hypersensitivity abrogated. Analyses of 18 surgical HCC specimens yielded no further examples for genetic or epigenetic inactivation of FANCC, FANCF, or FANCG in HCC, suggesting a low prevalence of proximal FA pathway inactivation in this tumor type. Conclusions: As the majority of HCC are chemoresistant, assessment of FA pathway function in HCC could identify small subpopulations of patients expected to predictably benefit from individualized treatment protocols using ICL-agents.

Guest: John Kanellopoulos, MD Associate Professor of Ophthalmology NYU School of MedicineNew York, NY

Guest: John Kanellopoulos, MD Associate Professor of Ophthalmology NYU School of MedicineNew York, NYDirector, Laservision.gr InstituteAthens, Greece

Gene therapy is a very promising approach to treat or to prevent diseases. However, progress in this field is hindered by lack of suitable vectors. Current research focuses on the development of novel nonviral biodegradable gene carriers with improved gene transfer activity and low toxicity. In the course of this thesis, a library of degradable DNA compacting domains based on oligomerized polyamines was synthesized and analyzed. Degradation of the originated polymers was either based on site-specific reductive cleavage of disulfide bonds or on time-dependent ester/amide hydrolysis. DNA binding activity, polyplex stability, transfection efficiency, toxicity, and hemocompatibility studies were performed in order to identify promising candidates. Some of the novel gene carriers, especially the degradable oligoethylenimine (OEI) derivatives were successfully applied for in vitro transfection and could easily compete with the current ‘golden standard’ linear polyethylenimine with an average Mw of 22 kDa (PEI22lin). Furthermore, screening results revealed critical structure activity relationships which were very helpful for improving the polymer design. According to transfection and biocompatibility results, efficiency and toxicity correlated to some degree. Polymers with an overall high charge density and a high molecular weight like OEI-HD-1 provided polyplex stability and formed small uniform particles. On the other hand these polymers tended to induce erythrocyte aggregation and exhibited a pronounced cytotoxicity when applied at high concentrations. Polycation with a lower molecular weight (~ 10 kDa) like e.g. OEI-IP-1 were essentially nontoxic, but had to be applied at high concentrations in order to achieve efficient gene transfer. Intrinsic membrane activity of certain polymers could damage cellular membranes but may also trigger endosomal release and therefore boost transfection activity. Crosslinking of OEI 800 with 1,6-hexanedioldiacrylate resulted in highly efficient degradable polycations. Different reaction temperatures during OEI-HD-1 synthesis had a strong impact on molecular weight and the ester/amide ratio. Despite structural differences, both OEI-HD-1 (synthesized at 60°C) and lt-OEI-HD-1 (synthesized at 20°C) possessed equal gene transfer activity as the ‘golden standard’ PEI22lin when applied at their optimal polymer/DNA-ratio (w/w). It was important to note that lt-OEI-HD-1, the LMW-derivative which is predominantly based on ester linkages, was significantly less toxic than its HMW amide-linked counterpart. OEI-HD displayed a very promising basis for the development of further powerful gene carriers. A two-step synthesis protocol was established in order to generate OEI-HD cores bearing excessive linker which could be subsequently modified with various functionalities like spermine. OEI-HD-Sper pseudo-dendrimers were characterized by a pronounced intrinsic membrane activity and possess high transfection efficiency. Since current nonviral vectors are still very inefficient as compared to their viral competitors, natural viruses present an ideal example educating us how to further optimize polycationic gene carriers in terms of specific cell-targeting and improved endosomal release. Modification of polyplexes towards a “smart” virus-like system was achieved in the following way. Degradable DNA compacting domains (OEI-HD-1) were utilized for complex formation. Furthermore, epidermal growth factor (EGF) was incorporated as targeting ligand into OEI-HD-1 polyplexes and thus allowed cell-specific cellular uptake via the EGF receptor (EGFR). Gene transfer potential of EGFR-targeted degradable polyplexes was further improved by applying technologies which promoted the endosomal release of endocytosed particles. Photochemical intracellular release (PCI) is based on accumulation of amphiphilic photosensitizers (PS) in endosomal membranes. Illumination of PS pre-treated transfected cells results in activation of the PS and subsequent light-induced rupture of endocytic vesicles. Combination of biological (EGFR) and physical (PCI) targeting greatly enhanced reporter gene delivery mediated by OEI-HD-1 polyplexes. Finally, the incorporation of membrane active melittin derivatives into EGF/OEI-HD-1 polyplexes was the first example of a biodegradable synthetic virus for gene delivery.

Thu, 22 Jul 2004 12:00:00 +0100 https://edoc.ub.uni-muenchen.de/2619/ https://edoc.ub.uni-muenchen.de/2619/1/Hahlen_Katrin.pdf Hahlen, Katrin ddc:570, ddc:500, Fakultät für Biologie

Mitochondria contain a complex machinery for the import of nuclear-encoded proteins. Receptor proteins exposed on the outer membrane surface are required for the specific binding of precursor proteins to mitochondria, either by binding of cytosolic signal recognition factors or by direct recognition of the precursor polypeptides. Subsequently, the precursors are inserted into the outer membrane at the general insertion site GIP (general insertion protein. Here we report the analysis of receptors and GIP by crosslinking of translocation intermediates and by coimmunoprecipitation. Surface-accumulated precursors were cross-linked to the receptors MOM19 and MOM72, suggesting a direct interaction of preproteins with surface receptors. We identified three novel mitochondrial outer membrane proteins, MOM7, MOMS, and MOM30 that, together with the previously identified MOM38, seem to form the GIP site and are present in the mitochondrial receptor complex.