20 research outputs found
High Throughput Genome-Wide Survey of Small RNAs from the Parasitic Protists Giardia intestinalis and Trichomonas vaginalis
RNA interference (RNAi) is a set of mechanisms which regulate gene expression in eukaryotes. Key elements of RNAi are small sense and antisense RNAs from 19 to 26 nt generated from double-stranded RNAs. MicroRNAs (miRNAs) are a major type of RNAi-associated small RNAs and are found in most eukaryotes studied to date. To investigate whether small RNAs associated with RNAi appear to be present in all eukaryotic lineages, and therefore present in the ancestral eukaryote, we studied two deep-branching protozoan parasites, Giardia intestinalis and Trichomonas vaginalis. Little is known about endogenous small RNAs involved in RNAi of these organisms. Using Illumina Solexa sequencing and genome-wide analysis of small RNAs from these distantly related deep-branching eukaryotes, we identified 10 strong miRNA candidates from Giardia and 11 from Trichomonas. We also found evidence of Giardia short-interfering RNAs potentially involved in the expression of variant-specific surface proteins. In addition, eight new small nucleolar RNAs from Trichomonas are identified. Our results indicate that miRNAs are likely to be general in ancestral eukaryotes and therefore are likely to be a universal feature of eukaryotes
PIWI Associated siRNAs and piRNAs Specifically Require the Caenorhabditis elegans HEN1 Ortholog henn-1
Small RNAs—including piRNAs, miRNAs, and endogenous siRNAs—bind Argonaute proteins to form RNA silencing complexes that target coding genes, transposons, and aberrant RNAs. To assess the requirements for endogenous siRNA formation and activity in Caenorhabditis elegans, we developed a GFP-based sensor for the endogenous siRNA 22G siR-1, one of a set of abundant siRNAs processed from a precursor RNA mapping to the X chromosome, the X-cluster. Silencing of the sensor is also dependent on the partially complementary, unlinked 26G siR-O7 siRNA. We show that 26G siR-O7 acts in trans to initiate 22G siRNA formation from the X-cluster. The presence of several mispairs between 26G siR-O7 and the X-cluster mRNA, as well as mutagenesis of the siRNA sensor, indicates that siRNA target recognition is permissive to a degree of mispairing. From a candidate reverse genetic screen, we identified several factors required for 22G siR-1 activity, including the chromatin factors mes-4 and gfl-1, the Argonaute ergo-1, and the 3′ methyltransferase henn-1. Quantitative RT–PCR of small RNAs in a henn-1 mutant and deep sequencing of methylated small RNAs indicate that siRNAs and piRNAs that associate with PIWI clade Argonautes are methylated by HENN-1, while siRNAs and miRNAs that associate with non-PIWI clade Argonautes are not. Thus, PIWI-class Argonaute proteins are specifically adapted to associate with methylated small RNAs in C. elegans
Transoral laser microsurgery for supraglottic carcinomas: results of a prospective multicenter trial (SUPRATOL)
Background A limited number of single institutions have published retrospective cohort studies on transoral laser microsurgery for supraglottic laryngectomy (TLM-SGL). These studies have shown that the oncologic outcomes of TLM-SGL are comparable to those of open SGL. However, there is limited information available regarding swallowing rehabilitation and quality of life (QoL). Patients and methods SUPRATOL is a prospective, multicenter trial assessing the functional outcomes of TLM-SGL +/− adjuvant radio-(chemo)-therapy. The primary endpoint was aspiration-free swallowing at 12 months, as established using fibreoptic endoscopic evaluation of swallowing (FEES) and defined as a grade < 6 on the penetration–aspiration scale. Secondary endpoints were swallowing- and voice-related QoL, the prevalence of temporary and permanent tracheostomy and percutaneous gastrostomy, local control, laryngectomy-free survival, overall survival, and disease-free survival, as well as the influence of treatment centers on outcomes. Results From April 2015 to February 2018, 102 patients were recruited from 26 German Otorhinolaryngology (ORL) hospitals. All patients had TLM-SGL and 96.1% underwent uni- or bilateral, mostly selective neck dissection. To 47.0% of patients, adjuvant radio-(chemo)-therapy (R(C)T) was administered. The median follow-up period was 24.1 months. At 12-month follow-up, completed by 84.3% of patients, 98.2%, 95.5%, and 98.8% were free of aspiration when tested with saliva, liquid, or pulp. Adjuvant R(C)T, pT category, and type of resection had no significant influence on swallowing rehabilitation. A total of 40.2% of patients had been tracheotomized, and in 46.1% of patients, a PEG tube was inserted. At the 24-month follow-up, 5.3% of patients still required a tracheostomy, and 8.0% continued to use a percutaneous endoscopic gastrostomy (PEG) tube. Deterioration of swallowing- and voice-related QoL was observed immediately after treatment, but patients recovered, and baseline values were reached again. The Kaplan–Meier 2-year rates for local control, laryngectomy-free survival, overall survival, and disease-free survival were 88%, 92%, 93%, and 82%, respectively. Conclusions Our prospective multicenter trial shows that, at 12 months post-TLM-SGL +/− R(C)T, 95.5%–98.8% of patients achieved aspiration-free swallowing. Morbidity was higher than previously reported. The rates of permanent tracheostomy and gastrostomy tube placement correspond to previous cohort studies. The 2-year oncologic outcomes are within the reported range. Clinical trial registration https://drks.de/search/en/trial/DRKS00004641 , identifier (DRKS00004641)
Stratified Administration of Serotonin 5-HT3 Receptor Antagonists (Setrons) for Chemotherapy-Induced Emesis: Economic Implications
The serotonin 5-HT3 receptor antagonists or `setrons' have become the standard of care for the prevention of chemotherapy-induced emesis (CIE) and are first-line therapy for acute CIE in healthcare organisations worldwide. However, their superior efficacy versus standard antiemetics comes at a significant cost. Currently, 3 agents are available in the US: ondansetron, granisetron and dolasetron. The most important treatment-related factor contributing to CIE is the emetogenicity of chemotherapy. The ability to customise, or stratify, the setron dose to match the emetogenic challenge of the chemotherapy administered has potential benefits, both clinically and economically. In adults, there is an appreciable amount of clinical literature addressing stratified administration; however, the amount of `hard' economic data is rather limited. Intuitively, if clinical outcomes are equivalent, then stratified administration should be associated with economic benefits, as it generally promotes the use of doses lower than those recommended by the manufacturer. The literature strongly substantiates this for ondansetron, but is not as favourable for granisetron or dolasetron. As the rationale and justification for dose stratification is contained in the clinical literature, the authors have reviewed the pertinent literature supporting the clinical and economic benefits of dose stratification in both adult and paediatric patients. The authors also provide a discussion of various additional strategies that can be employed to ensure the appropriate and cost-effective use of setrons in real-world practice settings. These strategies include the use of lower doses than recommended by manufacturers, use for acute versus delayed phase emesis, enhancing the antiemetic efficacy by the addition of a corticosteroid, use of oral versus injectable formulations (when appropriate) and the implementation and use of local, national and international drug use guidelines.Antiemetics, Children, Corticosteroids, Cost analysis, Dolasetron, Granisetron, Guideline utilisation, Nausea, Ondansetron, Pharmacoeconomics, Serotonin 3 receptor antagonists, Vomiting
Oral chemotherapy safety practices at US cancer centres: questionnaire survey
Objective To characterise current safety practices for the use of oral chemotherapy. Design Written questionnaire survey of pharmacy directors of cancer centres. Setting Comprehensive cancer centres in the United States. Results Respondents from 42 (78%) of 54 eligible centres completed the survey, after consulting with 89 colleagues. Clinicians at 29 centres used handwritten prescriptions, two used preprinted paper prescriptions, and six used electronic systems for most oral chemotherapy prescribing. For six commonly used oral chemotherapies, on average 10 centres required a diagnosis on the prescription, 11 required the protocol number, four required the cycle number, nine required double checking by a second clinician, 14 required a calculation of body surface area, and 14 required a calculation of dose per square metre of body surface area. Only a third of centres requested patients' written informed consent when oral chemotherapy was given off protocol. Nearly a quarter (10) of centres had no formal process for monitoring patients' adherence. In the past year respondents at 10 centres reported at least one serious adverse drug event related to oral chemotherapy, and respondents at 13 centres reported a serious near miss. Conclusion Few of the safeguards routinely used for infusion chemotherapy have been adopted for oral chemotherapy at US cancer centres. There is currently no consensus at these centres about safe medication practices for oral chemotherapy