429 research outputs found
Molecular rulers for measuring RNA structure: sites of crosslinking in chlorambucilyl-phenylalanyl-tRNA^(Phe) (yeast) and chlorambucilyl-pentadecaprolyl-phenylalanyl-tRNA^(Phe) (yeast) intramolecularly crosslinked in aqueous solution
Intramolecular crosslinking of yeast phenylalanine tRNA in aqueous solution with rigid, variable-length crosslinking reagents, which we call "molecular rulers," has given results in reasonable agreement with the crystal structure. Chlorambucilyl-[^(3)H]phenylalanyl-tRNA^(Phe) crosslinked intramolecularly at G-71 and A-73, whereas chlorambucilyl-pentadecaprolyl-[^(3)H]phenylalanyl-tRNA^(Phe) crosslinked at G-20 and Y-37. The pentadecaprolyl reagent was predicted to be 62 Ã… long, including chlorambucil and phenylalanine; the sites that it reached are 60 Ã… distant from the 3' OH (in the case of G-20) or 80 Ã… distant (in the case of Y-37) in the crystal structure of tRNA^(Phe). The close agreement between the length of the reagent and the distance of G-20 from the 3' OH in the crystal structure illustrates the rigidity of the tRNA^(Phe) molecule in the dihydrouridine loop region at the corner of the molecule. The apparent ability of the 62-Ã…-long reagent to crosslink to a site, Y-37, that is 80 Ã… distant from the 3' OH in the crystal structure appears to illustrate the flexibility of both the 3' A-C-C-A terminus and the anticodon stem and loop, with respect to the tRNA molecule. These observations demonstrate the utility of oligoproline-based crosslinking reagents as rigid, variable-length molecular rulers for biological macromolecules in solution
Coordinate control of cell cycle regulatory genes in zebrafish development tested by cyclin D1 knockdown with morpholino phosphorodiamidates and hydroxyprolyl-phosphono peptide nucleic acids
During early zebrafish (Danio rerio) development zygotic transcription does not begin until the mid-blastula transition (MBT) ∼3 h after fertilization. MBT demarcates transition from synchronous short cell cycles of S and M phases exclusively to full cycles encompassing G(1) and G(2) phases. Transcriptional profiling and RT–PCR analyses during these phases enabled us to determine that this shift corresponds to decreased transcript levels of S/M phase cell cycle control genes (e.g. ccna2, ccnb1, ccnb2 and ccne) and increased transcript levels of ccnd1, encoding cyclin D1, and orthologs of p21 (p21-like) and retinoblastoma (Rb-like 1). To investigate the regulation of this process further, the translation of ccnd1 mRNA, a G(1)/S checkpoint control element, was impaired by microinjection of ccnd1-specific morpholino phosphorodiamidate (MO) 20mer or hydroxyprolyl-phosphono peptide nucleic acid (HypNA-pPNA) 16mer antisense oligonucleotides. The resulting downregulation of cyclin D1 protein resulted in microophthalmia and microcephaly, but not lethality. The phenotypes were not seen with 3-mismatch MO 20mers or 1-mismatch HypNA-pPNA 16mers, and were rescued by an exogenous ccnd1 mRNA construct with five mismatches. Collectively, these results indicate that transcription of key molecular determinants of asynchronous cell cycle control in zebrafish embryos commences at MBT and that the reduction of cyclin D1 expression compromises zebrafish eye and head development
The inhibition of \u3cem\u3eStaphylococcus epidermidis\u3c/em\u3e biofilm formation by vancomycinmodified titanium alloy and implications for the treatment of periprosthetic infection
Peri-prosthetic infections are notoriously difficult to treat as the biomaterial implant is ideal for bacterial adhesion and biofilm formation, resulting in decreased antibiotic sensitivity. Previously, we reported that vancomycin covalently attached to a Ti alloy surface (Vanc-Ti) could prevent bacterial colonization. Herein we examine the effect of this Vanc-Ti surface on Staphylococci epidermidis, a Gram-positive organism prevalent in orthopaedic infections. By direct colony counting and fluorescent visualization of live bacteria, S. epidermidis colonization was significantly inhibited on Vanc-Ti implants. In contrast, the gram-negative organism Escherichia coli readily colonized the Vanc-Ti rod, suggesting retention of antibiotic specificity. By histochemical and SEM analysis, Vanc-Ti prevented S. epidermidis biofilm formation, even in the presence of serum. Furthermore, when challenged multiple times with S. epidermidis, Vanc-Ti rods resisted bacterial colonization. Finally, when S. epidermidis was continuously cultured in the presence of Vanc-Ti, the bacteria maintained a Vanc sensitivity equivalent to the parent strain. These findings indicate that antibiotic derivatization of implants can result in a surface that can resist bacterial colonization. This technology holds great promise for the prevention and treatment of periprosthetic infections
International consensus recommendations for management of new onset refractory status epilepticus including febrile infection-related epilepsy syndrome: Statements and supporting evidence
Objective: This study was undertaken to develop consensus-based recommendations for the management of adult and pediatric patients with new onset refractory status epilepticus (NORSE)/febrile infection-related epilepsy syndrome (FIRES) based on best evidence and experience. Methods: The Delphi methodology was followed. A facilitator group of nine experts was established, who defined the scope, users, and suggestions for recommendations. Following a review of the current literature, recommendation statements concerning diagnosis, treatment, and research directions were generated, which were then rated on a scale of 1 (strongly disagree) to 9 (strongly agree) by a panel of 48 experts in the field. Consensus that a statement was appropriate was reached if the median score was ≥7 and inappropriate if the median score was ≤3. The analysis of evidence was mapped to the results of each statement included in the Delphi survey. Results: Overall, 85 recommendation statements achieved consensus. The recommendations are divided into five sections: (1) disease characteristics; (2) diagnostic testing and sampling; (3) acute treatment; (4) treatment in the postacute phase; and (5) research, registries, and future directions in NORSE/FIRES. The detailed results and discussion of all 85 statements are outlined herein. A corresponding summary of findings and practical flowsheets are presented in a companion article. Significance: This detailed analysis offers insight into the supporting evidence and the current gaps in the literature that are associated with expert consensus statements related to NORSE/FIRES. The recommendations generated by this consensus can be used as a guide for the diagnosis, evaluation, and management of patients with NORSE/FIRES, and for planning of future research
General practitioners apply the usual care for shoulder complaints better than expected – analysis of videotaped consultations
BACKGROUND: The education and activation program (EAP) is a newly developed intervention to prevent the development of chronic shoulder complaints (SCs). Trained general practitioners (GPs) administer the EAP. The EAP addresses inadequate cognitions and maladaptive behavior related to the SCs. The effect of the EAP is evaluated in a randomized clinical trial. The aim of the present study is to use videotaped consultations to study (1) the performance of trained GPs administering the EAP and (2) the presence of key features of the EAP already embedded in usual care (UC). METHODS: Five trained GPs were videotaped while treating a standardized patient with EAP. Additionally, five GPs administering UC were videotaped. Two blinded observers evaluated the videotapes in relation to key features of the EAP which were scored on the EAP checklist. RESULTS: The mean total score on the EAP checklist was 4.7 (SD = 2.9) for the UC group and 7.1 (SD = 2.1) for the EAP group. Neither group reached a score higher than 8, which was considered to reflect an acceptable number of key EAP features. CONCLUSION: Our comparison of the presence of key features of EAP shows that the UC and EAP groups differed less than was expected. GPs in the UC group performed above expectation, with a mean total score of 4.7. Moreover, the low number of key features present in the EAP group may very well have led to a reduced effectiveness of the EAP. The results of this study can be used to optimize the training of GPs using the EAP
Improved biological activity of a mutant endostatin containing a single amino-acid substitution
Newly established tumourigenic primary human colon cancer cell lines are sensitive to TRAIL-induced apoptosis in vitro and in vivo
Most data on the therapeutic potential of tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) as well as resistance to FAS ligand (FASL) in colorectal cancer have come from in vitro studies using cell lines. To gain a clearer understanding about the susceptibility of patient tumours to TRAIL and FASL, we derived primary human cancer epithelial cells from colon cancer patients. Characterisation of primary cultures PAP60 and MIH55 determined their highly proliferating advantage, transforming capability and tumorigenicity in vitro and in vivo. Although FASL treatment appeared to cause little apoptosis only in the PAP60 primary culture, increased apoptosis independent of p53 was observed in both primary PAP60 and MIH55 and control cell lines Caco-2, HT29 and DLD-1 after treatment with SuperKiller TRAIL. Expression analysis of death receptors (DR) in the original parental tumours, the primary cultures before and after engraftment as well as the mouse xenografts, revealed a significant upregulation of both DR4 and DR5, which correlated to differences in sensitivity of the cells to TRAIL-induced apoptosis. Treating patient tumour xenograft/SCID mouse models with Killer TRAIL in vivo suppressed tumour growth. This is the first demonstration of TRAIL-induced apoptosis in characterised tumorigenic primary human cultures (in vitro) and antitumour activity in xenograft models (in vivo)
Updated consensus guidelines on the management of Phelan–McDermid syndrome
Phelan–McDermid syndrome (PMS) is a genetic condition caused by SHANK3 haploinsufficiency and characterized by a wide range of neurodevelopmental and systemic manifestations. The first practice parameters for assessment and monitoring in individuals with PMS were published in 2014; recently, knowledge about PMS has grown significantly based on data from longitudinal phenotyping studies and large-scale genotype–phenotype investigations. The objective of these updated clinical management guidelines was to: (1) reflect the latest in knowledge in PMS and (2) provide guidance for clinicians, researchers, and the general community. A taskforce was established with clinical experts in PMS and representatives from the parent community. Experts joined subgroups based on their areas of specialty, including genetics, neurology, neurodevelopment, gastroenterology, primary care, physiatry, nephrology, endocrinology, cardiology, gynecology, and dentistry. Taskforce members convened regularly between 2021 and 2022 and produced specialty-specific guidelines based on iterative feedback and discussion. Taskforce leaders then established consensus within their respective specialty group and harmonized the guidelines. The knowledge gained over the past decade allows for improved guidelines to assess and monitor individuals with PMS. Since there is limited evidence specific to PMS, intervention mostly follows general guidelines for treating individuals with developmental disorders. Significant evidence has been amassed to guide the management of comorbid neuropsychiatric conditions in PMS, albeit mainly from caregiver report and the experience of clinical experts. These updated consensus guidelines on the management of PMS represent an advance for the field and will improve care in the community. Several areas for future research are also highlighted and will contribute to subsequent updates with more refined and specific recommendations as new knowledge accumulates
The Hawthorne Effect: a randomised, controlled trial
Background: The 'Hawthorne Effect' may be an important factor affecting the generalisability of clinical research to routine practice, but has been little studied. Hawthorne Effects have been reported in previous clinical trials in dementia but to our knowledge, no attempt has been made to quantify them. Our aim was to compare minimal follow- up to intensive follow-up in participants in a placebo controlled trial of Ginkgo biloba for treating mild-moderate dementia.Methods: Participants in a dementia trial were randomised to intensive follow- up (with comprehensive assessment visits at baseline and two, four and six months post randomisation) or minimal follow-up (with an abbreviated assessment at baseline and a full assessment at six months). Our primary outcomes were cognitive functioning (ADAS-Cog) and participant and carer-rated quality of life (QOL-AD).Results: We recruited 176 participants, mainly through general practices. The main analysis was based on Intention to treat (ITT), with available data. In the ANCOVA model with baseline score as a co- variate, follow-up group had a significant effect on outcome at six months on the ADAS-Cog score (n = 140; mean difference = -2.018; 95% Cl -3.914, -0.121; p = 0.037 favouring the intensive follow-up group), and on participant- rated quality of life score (n = 142; mean difference = -1.382; 95% Cl -2.642, -0.122; p = 0.032 favouring minimal follow-up group). There was no significant difference on carer quality of life.Conclusion: We found that more intensive follow-up of individuals in a placebo-controlled clinical trial of Ginkgo biloba for treating mild-moderate dementia resulted in a better outcome than minimal follow-up, as measured by their cognitive functioning
Disordered Structural Ensembles of Vasopressin and Oxytocin and Their Mutants
Vasopressin and oxytocin are intrinsically disordered cyclic nonapeptides belonging to a family of neurohypophysial hormones. Although unique in their functions, these peptides differ only by two residues and both feature a tocin ring formed by the disulfide bridge between first and sixth cysteine residues. This sequence and structural similarity are experimentally linked to oxytocin agonism at vasopressin receptors and vasopressin antagonism at oxytocin receptors. Yet single- or double-residue mutations in both peptides have been shown to have drastic impacts on their activities at either receptor, and possibly the ability to bind to their neurophysin carrier protein. In this study we perform molecular dynamics simulations of the unbound native and mutant sequences of the oxytocin and vasopressin hormones to characterize their structural ensembles. We classify the subpopulations of these structural ensembles on the basis of the distributions of radius of gyration and secondary structure and hydrogen-bonding features of the canonical tocin ring and disordered tail region. We then relate the structural changes observed in the unbound form of the different hormone sequences to experimental information about peptide receptor binding, and more indirectly, carrier protein binding affinity, receptor activity, and protease degradation. This study supports the hypothesis that the structural characteristics of the unbound form of an IDP can be used to predict structural or functional preferences of its functional bound form
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