ABSTRACT
A 25-month-old child presented with unilateral hearing loss; examination found unilateral right middle ear effusion of cerebrospinal fluid. What is your diagnosis?
Subject(s)
Ear, Middle , Otitis Media with Effusion , Child , Humans , Otitis Media with Effusion/diagnosisABSTRACT
Langerhans cell histiocytosis is a rare condition affecting the temporal bone in up to 60% of cases. Symptoms are non-specific and the differential diagnosis includes infection, benign lesions such as cholesteatoma, and malignant lesions of the skull base. Here, we report the case of a 14-yearold child referred with chronic ear discharge, and background of multifocal Langerhans cell histiocytosis 9 years prior. Recurrence of Langerhans cell histiocytosis was initially suspected and systemic treatment was considered. Further imaging workup and surgical exploration of the mastoid showed a secondary acquired cholesteatoma arising from a dehiscent posterior ear canal wall. Surgical removal of the cholesteatoma was performed with a canal wall down procedure. We review the presentation and management of temporal bone Langerhans cell histiocytosis. We recommend that cholesteatoma should be considered in case of recurrence of otological symptoms in patients with a background of Langerhans cell histiocytosis.
Subject(s)
Cholesteatoma, Middle Ear , Cholesteatoma , Ear Diseases , Histiocytosis, Langerhans-Cell , Adolescent , Humans , Cholesteatoma/diagnosis , Cholesteatoma/surgery , Cholesteatoma, Middle Ear/diagnostic imaging , Cholesteatoma, Middle Ear/surgery , Ear Canal/surgery , Ear Diseases/pathology , Histiocytosis, Langerhans-Cell/diagnosis , Histiocytosis, Langerhans-Cell/surgery , Mastoid/diagnostic imaging , Mastoid/surgery , Mastoid/pathology , Recurrence , Retrospective Studies , Temporal Bone/diagnostic imaging , Temporal Bone/surgery , Temporal Bone/pathologyABSTRACT
Airway surgery involving trachea or main stem bronchi in neonates and children is challenging. The use of extracorporeal support for such unusual indications is poorly described. Here, we report on three patients receiving peripheral extracorporeal membrane oxygenation (ECMO) to maintain adequate ventilation while improving surgical site exposure. Case 1 is a 9-year-old boy diagnosed with proximal left stem bronchus endoluminal tumor; cases 2 and 3 are a neonate and a young infant diagnosed with a subcarinal bronchogenic cyst. Planned ECMO use consisted in peripheral venoarterial cannulation through jugular and carotid access. There was no bleeding complication during and after surgical care. Hemodynamic and respiratory supports were optimized in all cases. Children were successfully weaned off ECMO immediately after surgery. Planned peripheral ECMO cannulation offers optimal conditions for high-risk airway surgery in neonates and children.
Subject(s)
Extracorporeal Membrane Oxygenation , Catheterization , Child , Extracorporeal Membrane Oxygenation/adverse effects , Hemodynamics , Humans , Infant , Infant, Newborn , Male , Retrospective Studies , TracheaABSTRACT
Treacher Collins syndrome (TCS) is a frequent cause of mandibulofacial dysostosis. To date, TCS-causing mutations in three genes, namely TCOF1, POLR1D, and POLR1C have been identified. TCS is usually inherited in an autosomal dominant manner, with a high clinical variability and no phenotype-genotype correlation. Up-to now, five families have been reported with an autosomal recessive mode of inheritance due to mutations in POLR1D or POLR1C. We report here a new family with two sisters affected by mild TCS carrying compound POLR1C heterozygous mutations, and review the literature on mild forms of TCS, autosomal recessive inheritance in this syndrome and POLR1C mutations.
Subject(s)
DNA-Directed RNA Polymerases/genetics , Genes, Recessive , Mandibulofacial Dysostosis/genetics , Mutation , Child, Preschool , Female , Humans , Magnetic Resonance Imaging , Mandibulofacial Dysostosis/drug therapyABSTRACT
OBJECTIVES: To test the clinical and audiometric efficacy of a minimally invasive myringoplasty technique, combining cartilaginous palisades while avoiding flap elevation, for small and wide perforations. METHODS: Over 4 years, this retrospective study included all patients over 6 years of age presenting an indication for myringoplasty. Several clinical and economic criteria were noted at 7 d, 2 months, 6 months and 2 years postoperative. The main outcome was the absence of perforation 2 years postoperative. The secondary outcomes were an audiometric gain at 6 months and the evaluation of the treatment cost. RESULTS: Thirty patients underwent the minimally invasive technique and 28 patients the technique with an elevation of the tympanomeatal flap. The minimally invasive surgical procedure was shorter (p = .001). At 2 years, the tympanic closure rate was equivalent (95% versus 89.5%, p = .77). The audiometric gain was similar between the two techniques (p = .09). From a medico-economic point of view, the minimally invasive procedure was the most effective because it was three times less expensive than the conventional technique with no reduction in efficacy (p = .02). CONCLUSION: This quick and easy technique could be developed in an ambulatory setting or even in conditions adapted to consultation.
Subject(s)
Health Care Costs , Minimally Invasive Surgical Procedures/economics , Myringoplasty/methods , Tympanic Membrane Perforation/surgery , Adolescent , Adult , Aged , Audiometry , Child , Humans , Middle Aged , Myringoplasty/economics , Retrospective Studies , Speech Reception Threshold Test , Tympanic Membrane/injuries , Tympanic Membrane/surgery , Young AdultABSTRACT
Importance: Low cardiac output syndrome after cardiac surgery is associated with high morbidity and mortality in patients with impaired left ventricular function. Objective: To assess the ability of preoperative levosimendan to prevent postoperative low cardiac output syndrome. Design, Setting, and Participants: Randomized, double-blind, placebo-controlled trial conducted in 13 French cardiac surgical centers. Patients with a left ventricular ejection fraction less than or equal to 40% and scheduled for isolated or combined coronary artery bypass grafting with cardiopulmonary bypass were enrolled from June 2013 until May 2015 and followed during 6 months (last follow-up, November 30, 2015). Interventions: Patients were assigned to a 24-hour infusion of levosimendan 0.1 µg/kg/min (n = 167) or placebo (n = 168) initiated after anesthetic induction. Main Outcomes and Measures: Composite end point reflecting low cardiac output syndrome with need for a catecholamine infusion 48 hours after study drug initiation, need for a left ventricular mechanical assist device or failure to wean from it at 96 hours after study drug initiation when the device was inserted preoperatively, or need for renal replacement therapy at any time postoperatively. It was hypothesized that levosimendan would reduce the incidence of this composite end point by 15% in comparison with placebo. Results: Among 336 randomized patients (mean age, 68 years; 16% women), 333 completed the trial. The primary end point occurred in 87 patients (52%) in the levosimendan group and 101 patients (61%) in the placebo group (absolute risk difference taking into account center effect, -7% [95% CI, -17% to 3%]; P = .15). Predefined subgroup analyses found no interaction with ejection fraction less than 30%, type of surgery, and preoperative use of ß-blockers, intra-aortic balloon pump, or catecholamines. The prevalence of hypotension (57% vs 48%), atrial fibrillation (50% vs 40%), and other adverse events did not significantly differ between levosimendan and placebo. Conclusions and Relevance: Among patients with low ejection fraction who were undergoing coronary artery bypass grafting with cardiopulmonary bypass, levosimendan compared with placebo did not result in a significant difference in the composite end point of prolonged catecholamine infusion, use of left ventricular mechanical assist device, or renal replacement therapy. These findings do not support the use of levosimendan for this indication. Trial Registration: EudraCT Number: 2012-000232-25; clinicaltrials.gov Identifier: NCT02184819.
Subject(s)
Cardiac Output, Low/prevention & control , Cardiotonic Agents/therapeutic use , Coronary Artery Bypass/adverse effects , Hydrazones/therapeutic use , Premedication , Pyridazines/therapeutic use , Aged , Cardiopulmonary Bypass , Cardiotonic Agents/adverse effects , Catecholamines/administration & dosage , Double-Blind Method , Female , Heart-Assist Devices , Humans , Hydrazones/adverse effects , Infusions, Intravenous , Intention to Treat Analysis , Male , Middle Aged , Postoperative Complications/prevention & control , Pyridazines/adverse effects , Renal Replacement Therapy , Simendan , Stroke Volume/drug effects , Treatment FailureABSTRACT
Lung adenocarcinoma, the most common subtype of lung cancer, is the leading cause of cancer death worldwide. Despite attempts for the treatment of lung cancer which have been accumulating, promising new therapies are still needed. Here, we found that cyclic-AMP response element-binding protein (CREB)-CREB binding protein (CBP) transcription factors complex inhibitor, Naphthol AS-TR phosphate (NASTRp), is a potential therapeutic agent for lung cancer. We show that NASTRp inhibited oncogenic cell properties through cell cycle arrest with concomitant suppression of tumor-promoting autophagy with down-regulations of Atg5-12 and Atg7, and accumulation of p62 in human lung cancer cell lines. In addition, NASTRp induced expression of endoplasmic reticulum stress markers such as DDIT3/CHOP, and led to apoptosis along with Bim induction. These findings suggest that transcription factor/co-activator complex, CREB-CBP, can be a potential therapeutic target and its inhibition could be a novel therapeutic strategy for lung cancer.
Subject(s)
Anilides/pharmacology , Antineoplastic Agents/pharmacology , Cyclic AMP Response Element-Binding Protein/antagonists & inhibitors , Organophosphates/pharmacology , Peptide Fragments/antagonists & inhibitors , Sialoglycoproteins/antagonists & inhibitors , Adenocarcinoma/metabolism , Adenocarcinoma/mortality , Adenocarcinoma/pathology , Adenocarcinoma of Lung , Anilides/chemistry , Antineoplastic Agents/chemistry , Apoptosis Regulatory Proteins/metabolism , Autophagy , Autophagy-Related Protein 7 , Bcl-2-Like Protein 11 , Cell Cycle Checkpoints , Cell Line, Tumor , Cyclic AMP Response Element-Binding Protein/chemistry , Drug Screening Assays, Antitumor , Endoplasmic Reticulum Stress , Humans , Inhibitory Concentration 50 , Kaplan-Meier Estimate , Lung Neoplasms/metabolism , Lung Neoplasms/mortality , Lung Neoplasms/pathology , Membrane Proteins/metabolism , Molecular Docking Simulation , Organophosphates/chemistry , Peptide Fragments/chemistry , Proportional Hazards Models , Protein Binding , Proto-Oncogene Proteins/metabolism , Sialoglycoproteins/chemistry , Ubiquitin-Activating Enzymes/metabolismABSTRACT
The aryl-substituted bis(imino)pyridine cobalt methyl complex, ((Mes)PDI)CoCH3 ((Mes)PDI = 2,6-(2,4,6-Me3C6H2-NâCMe)2C5H3N), promotes the catalytic dehydrogenative silylation of linear α-olefins to selectively form the corresponding allylsilanes with commercially relevant tertiary silanes such as (Me3SiO)2MeSiH and (EtO)3SiH. Dehydrogenative silylation of internal olefins such as cis- and trans-4-octene also exclusively produces the allylsilane with the silicon located at the terminus of the hydrocarbon chain, resulting in a highly selective base-metal-catalyzed method for the remote functionalization of C-H bonds with retention of unsaturation. The cobalt-catalyzed reactions also enable inexpensive α-olefins to serve as functional equivalents of the more valuable α, ω-dienes and offer a unique method for the cross-linking of silicone fluids with well-defined carbon spacers. Stoichiometric experiments and deuterium labeling studies support activation of the cobalt alkyl precursor to form a putative cobalt silyl, which undergoes 2,1-insertion of the alkene followed by selective ß-hydrogen elimination from the carbon distal from the large tertiary silyl group and accounts for the observed selectivity for allylsilane formation.
ABSTRACT
Of the numerous oncogenes implicated in human cancer, the most common and perhaps the most elusive to target pharmacologically is RAS. Since the discovery of RAS in the 1960s, numerous studies have elucidated the mechanism of activity, regulation, and intracellular trafficking of the RAS gene products, and of its regulatory pathways. These pathways yielded druggable targets, such as farnesyltransferase, during the 1980s to 1990s. Unfortunately, early clinical trials investigating farnesyltransferase inhibitors yielded disappointing results, and subsequent interest by pharmaceutical companies in targeting RAS waned. However, recent advances including the identification of novel regulatory enzymes (e.g., Rce1, Icmt, Pdeδ), siRNA-based synthetic lethality screens, and fragment-based small-molecule screens, have resulted in a "Ras renaissance," signified by new Ras and Ras pathway-targeted therapies that have led to new clinical trials of patients with Ras-driven cancers. This review gives an overview of KRas signaling pathways with an emphasis on novel targets and targeted therapies, using non-small cell lung cancer as a case example.
Subject(s)
Antineoplastic Agents/therapeutic use , Carcinoma, Non-Small-Cell Lung/drug therapy , Lung Neoplasms/drug therapy , Molecular Targeted Therapy , Mutation/genetics , Proto-Oncogene Proteins/genetics , Signal Transduction/drug effects , ras Proteins/genetics , Carcinoma, Non-Small-Cell Lung/genetics , Carcinoma, Non-Small-Cell Lung/pathology , Humans , Lung Neoplasms/genetics , Lung Neoplasms/pathology , Prognosis , Proto-Oncogene Proteins p21(ras)ABSTRACT
BACKGROUND: The optimal age for assessing language difficulties in premature children remains unclear. AIMS: To determine the most predictive and earliest screening tool for later language difficulties on children born preterm. STUDY DESIGN: A prospective population-based study in the Loire Infant Follow-up Team LIFT SUBJECTS: All children born <35weeks of gestation between 2003 and 2005 were assessed at corrected ages by four screening tools: the Ages & Stages Questionnaire (ASQ) communication scale at 18 and 24months, the language items of Brunet Lezine test at 24months, and the "Epreuves de Repérage des Troubles du Langage" (ERTL) at 4years. OUTCOME MEASURES: After 5years, the kindergarten teacher evaluated the vocabulary, grammar and pronunciation capacities of the child in comparison with the classroom performances. RESULTS: Among 1957 infants enrolled at discharge, 947 were assessed by their teacher with 12.2% (n=116) of language difficulties. Full data at all time points were available for 426 infants. The area under curve of the receiver operator characteristic curve obtained for the ASQ communication scale at 18months was significantly lower (0.65±0.09) than that obtained at 24months (0.77±0.08) and the languages items of Brunet Lezine test at 24months (0.77±0.08), and the ERTL at 4years (0.76±0.09). The optimal cut-off value for ASQ communication at 24months is ≤45 [sensitivity of 0.79 (95%CI: 0.70-0.86); specificity of 0.63 (95%CI: 0.59-0.66)]. CONCLUSIONS: The Ages & Stages Questionnaire communication scale at 24 corrected months appears as an acceptable test at an early time point to identify preterm children at risk of later language difficulties.
Subject(s)
Infant, Premature , Language Development Disorders/diagnosis , Child, Preschool , Early Diagnosis , Female , Follow-Up Studies , Gestational Age , Humans , MaleABSTRACT
Illnesses that are caused by smoking remain as the world's leading cause of preventable death. Smoking and tobacco use constitute approximately 30% of all cancer-related deaths and nearly 90% of lung cancer-related deaths. Thus, improving smoking cessation interventions is crucial to reduce tobacco use and assist in minimizing the burden of cancer and other diseases in the United States. This review focuses on the existing research on framed messages to promote smoking cessation. Consistent with the tenets of prospect theory and recent meta-analysis, gain-framed messages emphasizing the benefits of quitting seem to be preferable when working with adult patients who smoke tobacco products. The evidence also suggests that moderators of treatment should guide framed statements made to patients. Meta-analyses have provided consistent moderators of treatment such as need for cognition, but future studies should further define the specific framed interventions that would be most helpful for subgroups of smokers. In conclusion, instead of using loss-framed statements like "Smoking will harm your health by causing problems like lung and other cancers, heart disease, and stroke," as a general rule, physicians should use gain-framed statements like "Quitting smoking will benefit your health by preventing problems like lung and other cancers, heart disease, and stroke."
Subject(s)
Smoking Cessation , Tobacco Use Cessation , Humans , Lung Neoplasms/prevention & control , Physician's Role , Text MessagingSubject(s)
Angiogenesis Inhibitors/adverse effects , Biomarkers, Tumor/metabolism , Carcinoma, Squamous Cell/metabolism , Lung Neoplasms/metabolism , Receptors, Vascular Endothelial Growth Factor/metabolism , Signal Transduction/drug effects , Vascular Endothelial Growth Factor A/metabolism , Adenocarcinoma/metabolism , Adenocarcinoma of Lung , Angiogenesis Inhibitors/administration & dosage , Carcinoma, Squamous Cell/blood supply , Carcinoma, Squamous Cell/drug therapy , Carcinoma, Squamous Cell/pathology , Gene Expression Regulation, Neoplastic , Hemorrhage/chemically induced , Humans , Lung Neoplasms/blood supply , Lung Neoplasms/drug therapy , Lung Neoplasms/pathology , Neoplasm Staging , Predictive Value of Tests , Prognosis , Receptors, Vascular Endothelial Growth Factor/drug effects , Treatment Outcome , Vascular Endothelial Growth Factor A/drug effects , Vascular Endothelial Growth Factor Receptor-1/metabolism , Vascular Endothelial Growth Factor Receptor-2/metabolism , Vascular Endothelial Growth Factor Receptor-3/metabolismABSTRACT
Basic difference: The importance of a pendent base in promoting proton-coupled electron-transfer reactions with low activation barriers has been discussed for H(+) reduction or H(2) oxidation in acetonitrile. Investigation of the interaction between a base positioned in the second coordination sphere of a complex and a water ligand in water oxidation reactions using geometric isomers of [Ru(tpy)(pynap)(OH(2))](2+) (see picture) gave intriguing results.
Subject(s)
Organometallic Compounds/chemistry , Protons , Ruthenium/chemistry , Water/chemistry , Catalysis , Hydrogen-Ion Concentration , Models, Molecular , Molecular Structure , Oxidation-Reduction , StereoisomerismABSTRACT
Vascular endothelial growth factor (VEGF) plays an important role in the pathogenesis of neovascular age-related macular degeneration and diabetic retinopathy. Bevacizumab, an anti-VEGF monoclonal antibody, is efficacious for these disorders, but requires monthly intravitreal administration, with associated discomfort, cost, and adverse event risk. We hypothesized that a single intravitreal administration of adeno-associated virus (AAV) vector expressing bevacizumab would result in persistent eye expression of bevacizumab and suppress VEGF-induced retinal neovascularization. We constructed an AAV rhesus serotype rh.10 vector to deliver bevacizumab (AAVrh.10BevMab) and assessed its ability to suppress neovascularization in transgenic mice overexpressing human VEGF165 in photoreceptors. Intravitreal AAVrh.10BevMab directed long-term bevacizumab expression in the retinal pigmented epithelium. Treated homozygous mice had reduced levels of neovascularization, with 90±4% reduction 168 days following treatment. Thus, a single administration of AAVrh.10BevMab provides long-term suppression of neovascularization without the costs and risks associated with the multiple administrations required for the current conventional bevacizumab monoclonal drug delivery.
Subject(s)
Angiogenesis Inhibitors/administration & dosage , Antibodies, Monoclonal, Humanized/administration & dosage , Dependovirus/genetics , Genetic Vectors/therapeutic use , Neovascularization, Pathologic/prevention & control , Retinal Pigment Epithelium/blood supply , Vascular Endothelial Growth Factor A/genetics , Animals , Bevacizumab , Fluorescent Antibody Technique , Genetic Therapy , Homozygote , Humans , Macaca mulatta , Male , Mice , Mice, Inbred C57BL , Mice, Transgenic , Retinal Pigment Epithelium/metabolism , Retinal Pigment Epithelium/pathology , Vitreous Body/physiopathologyABSTRACT
This randomized, comparative, phase-IIIb study conducted in France aimed to demonstrate whether seroprotection against diphtheria, tetanus and poliomyelitis 1 month after a single dose of REVAXIS (low-dose diphtheria) is non-inferior to seroprotection 1 month after a single dose of DT Polio (standard-dose diphtheria), both vaccines being given as a second booster to healthy children at 6 years of age. Children were randomly assigned to receive a single intramuscular dose of REVAXIS or DT Polio. Primary endpoints were the 1-month post-booster seroprotection rates for diphtheria, tetanus and poliovirus type-1, -2 and -3 antigens. Secondary endpoints were immunogenicity and safety observations. Of 788 children screened, 760 were randomized: REVAXIS group, 384 children; DT Polio group, 376 children. No relevant difference in demographic characteristics at baseline was observed between REVAXIS and DT Polio groups. Non-inferiority of REVAXIS compared with DT Polio for seroprotection was demonstrated against diphtheria (respectively 98.6% and 99.3%), tetanus (respectively 99.6% and 100%), and poliovirus antigens (100% for each types in both groups). No allergic reactions to REVAXIS were reported. A benefit/risk ratio in favor of REVAXIS was suggested by the trend towards a better tolerability of REVAXIS compared with DT Polio regarding the rate of severe solicited injection-site reactions. The results support the use of REVAXIS as a booster at 6 years of age in infants who previously received a three-dose primary series within the first 6 months of life and a first booster including diphtheria, tetanus and poliovirus vaccine(s) given before 2 years of age.
Subject(s)
Diphtheria Toxoid/adverse effects , Diphtheria Toxoid/immunology , Diphtheria/prevention & control , Immunization, Secondary/adverse effects , Immunization, Secondary/methods , Poliomyelitis/prevention & control , Poliovirus Vaccines/adverse effects , Poliovirus Vaccines/immunology , Tetanus Toxoid/adverse effects , Tetanus Toxoid/immunology , Tetanus/prevention & control , Child , Diphtheria Toxoid/administration & dosage , Female , France , Humans , Hypersensitivity , Incidence , Injections, Intramuscular , Male , Poliovirus Vaccines/administration & dosage , Skin Diseases/chemically induced , Tetanus Toxoid/administration & dosage , Vaccines, Combined/administration & dosage , Vaccines, Combined/adverse effects , Vaccines, Combined/immunologyABSTRACT
The aerosol form of the bacterium Yersinia pestis causes pneumonic plague, a rapidly fatal disease that is a biothreat if deliberately released. At present, no plague vaccines are available for use in the United States, but subunit vaccines based on the Y. pestis V antigen and F1 capsular protein show promise when administered with adjuvants. In the context that adenovirus (Ad) gene transfer vectors have a strong adjuvant potential related to the ability to directly infect dendritic cells, we hypothesized that modification of the Ad5 capsid to display either the Y. pestis V antigen or the F1 capsular antigen on the virion surface would elicit high V antigen- or F1-specific antibody titers, permit boosting with the same Ad serotype, and provide better protection against a lethal Y. pestis challenge than immunization with equivalent amounts of V or F1 recombinant protein plus conventional adjuvant. We constructed AdYFP-pIX/V and AdLacZ-pIX/F1, E1(-), E3(-) serotype 5 Ad gene transfer vectors containing a fusion of the sequence for either the Y. pestis V antigen or the F1 capsular antigen to the carboxy-terminal sequence of pIX, a capsid protein that can accommodate the entire V antigen (37 kDa) or F1 protein (15 kDa) without disturbing Ad function. Immunization with AdYFP-pIX/V followed by a single repeat administration of the same vector at the same dose resulted in significantly better protection of immunized animals compared with immunization with a molar equivalent amount of purified recombinant V antigen plus Alhydrogel adjuvant. Similarly, immunization with AdLacZ-pIX/F1 in a prime-boost regimen resulted in significantly enhanced protection of immunized animals compared with immunization with a molar-equivalent amount of purified recombinant F1 protein plus adjuvant. These observations demonstrate that Ad vaccine vectors containing pathogen-specific antigens fused to the pIX capsid protein have strong adjuvant properties and stimulate more robust protective immune responses than equivalent recombinant protein-based subunit vaccines administered with conventional adjuvant, suggesting that F1-and/or V-modified capsid Ad-based recombinant vaccines should be considered for development as anti-plague vaccines.
Subject(s)
Adenoviridae/genetics , Antigens, Bacterial/immunology , Bacterial Proteins/immunology , Bacterial Vaccines/immunology , Capsid , Plague , Pore Forming Cytotoxic Proteins/immunology , Yersinia pestis , Blotting, Western , Genetic Vectors , Immunization , Plague/immunology , Plague/prevention & control , Recombinant Proteins/genetics , Recombinant Proteins/immunology , Yersinia pestis/genetics , Yersinia pestis/immunologyABSTRACT
The synthesis of complexes [Ru(II)(trpy)(2-imino-4-tert-butylquinone)(Cl)](+) and [Ru(II)(trpy)(NIL)(OAc)](+) (where trpy = 2:2',6':2''-terpyridyl, NIL = 2-imino-4-tert-butylquinone, 2-imino-4-methylquinone, 2-iminoquinone, 2-imino-4-chloroquinone, 2-imino-5-chloroquinone, 2-imino-4,6-di-tert-butyl-N-phenyl-quinone, 2-imino-4,6-di-tert-butyl-N-(2'-trifluoromethylphenyl)-quinone) is reported. The oxidation states of these complexes, as well as the previously reported [Ru(III)(trpy)(2-iminosemiquinone)(Cl)](+) complex, are investigated by spectroscopic, electrochemical and theoretical methods resulting in the latter complex being reassigned as [Ru(II)(trpy)(2-iminoquinone)(Cl)](+). Evidence for the presence of two structural isomers was found for all complexes, and crystal structures for both isomers of the [Ru(II)(trpy)(2-imino-4-tert-butylquinone)(Cl)]ClO(4) complex are reported, as well as for the cis isomer of [Ru(II)(trpy)(2-imino-4,6-di-tert-butyl-N-phenyl-quinone)(OAc)]PF(6). Redox control is also demonstrated based on the Hammett parameters of the substituents on the 2-iminoquinone ligand.
Subject(s)
Computer Simulation , Models, Chemical , Organometallic Compounds/chemistry , Quinones/chemistry , Ruthenium/chemistry , Crystallography, X-Ray , Models, Molecular , Molecular Conformation , Organometallic Compounds/chemical synthesis , Oxidation-Reduction , StereoisomerismABSTRACT
The proliferative capacity of pluripotent stem cells and their progeny brings a unique aspect to therapeutics, in that once a transplant is initiated the therapist no longer has control of the therapy. In the context of the recent FDA approval of a human ESC trial and report of a neuronal-stem-cell-derived tumor in a human trial, strategies need to be developed to control wayward pluripotent stem cells. Here, we focus on one approach: direct genetic modification of the cells prior to transplantation with genes that can prevent the adverse events and/or eliminate the transplanted cells and their progeny.