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1.
BMC Oral Health ; 21(1): 332, 2021 07 05.
Artigo em Inglês | MEDLINE | ID: mdl-34225707

RESUMO

BACKGROUND: Vitamin D is critical for bone physiology. In this study, we quantified Vitamin D Binding Protein (VitDBP) levels in saliva as a measure of Vitamin D during orthodontic tooth movement. METHODS: In this longitudinal study, saliva samples were collected from 73 orthodontic patients for 4 timepoints for the first six months of orthodontic treatment, along with dental casts at the beginning and the end of the study period. The saliva was measured for VitDBP as a biological marker for bone apposition and clinical tooth movement. We used the absolute change in Little's Irregularity Index as a quantitative measure for alignment. In addition, we measured the levels of alkaline phosphatase (ALP) in saliva as a marker of bone turnover. RESULTS: Both low (< 2.75 ng/ml) and high (> 6.48 ng/ml) VitDBP levels were associated with reduced tooth movement. Significant (p < 0.05) seasonal changes in VitDBP using a two-season year model were found with lower levels observed in the summer (Apr-Sept) than in the winter (Oct-Mar). CONCLUSIONS: Clinically significant orthodontic tooth movement is associated with an optimal range of VitDBP in saliva. Normal levels of VitDBP correlated with more orthodontic tooth movement, suggesting a "normal" range of salivary content of VitDBP. Given the strong trend that is independent of the confounding factors (ex. age, race or gender), the predictive value or salivary VitDBP for tooth movement should be studied in larger cohorts in future studies.


Assuntos
Técnicas de Movimentação Dentária , Proteína de Ligação a Vitamina D , Remodelação Óssea , Humanos , Estudos Longitudinais , Saliva
2.
J Biol Chem ; 289(50): 34683-98, 2014 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-25281741

RESUMO

Eukaryotic pre-mRNA splicing is an essential step in gene expression for all genes that contain introns. In contrast to transcription and translation, few well characterized chemical inhibitors are available with which to dissect the splicing process, particularly in cells. Therefore, the identification of specific small molecules that either inhibit or modify pre-mRNA splicing would be valuable for research and potentially also for therapeutic applications. We have screened a highly curated library of 71,504 drug-like small molecules using a high throughput in vitro splicing assay. This identified 10 new compounds that both inhibit pre-mRNA splicing in vitro and modify splicing of endogenous pre-mRNA in cells. One of these splicing modulators, DDD00107587 (termed "madrasin," i.e. 2-((7methoxy-4-methylquinazolin-2-yl)amino)-5,6-dimethylpyrimidin-4(3H)-one RNAsplicing inhibitor), was studied in more detail. Madrasin interferes with the early stages of spliceosome assembly and stalls spliceosome assembly at the A complex. Madrasin is cytotoxic at higher concentrations, although at lower concentrations it induces cell cycle arrest, promotes a specific reorganization of subnuclear protein localization, and modulates splicing of multiple pre-mRNAs in both HeLa and HEK293 cells.


Assuntos
Precursores de RNA/genética , Splicing de RNA/efeitos dos fármacos , Bibliotecas de Moléculas Pequenas/farmacologia , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/genética , Avaliação Pré-Clínica de Medicamentos , Células HEK293 , Células HeLa , Ensaios de Triagem em Larga Escala , Humanos , Quinazolinas/química , Quinazolinas/farmacologia , RNA Mensageiro/genética , Bibliotecas de Moléculas Pequenas/química
3.
ACS Omega ; 9(3): 3454-3468, 2024 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-38284090

RESUMO

Protein-protein interactions (PPIs) play a central role in nearly all cellular processes. The strength of the binding in a PPI is characterized by the binding affinity (BA) and is a key factor in controlling protein-protein complex formation and defining the structure-function relationship. Despite advancements in understanding protein-protein binding, much remains unknown about the interfacial region and its association with BA. New models are needed to predict BA with improved accuracy for therapeutic design. Here, we use machine learning approaches to examine how well different types of interfacial contacts can be used to predict experimentally determined BA and to reveal the impact of the specific amino acids at the binding interface on BA. We create a series of multivariate linear regression models incorporating different contact features at both residue and atomic levels and examine how different methods of identifying and characterizing these properties impact the performance of these models. Particularly, we introduce a new and simple approach to predict BA based on the quantities of specific amino acids at the protein-protein interface. We found that the numbers of specific amino acids at the protein-protein interface were correlated with BA. We show that the interfacial numbers of amino acids can be used to produce models with consistently good performance across different data sets, indicating the importance of the identities of interfacial amino acids in underlying BA. When trained on a diverse set of complexes from two benchmark data sets, the best performing BA model was generated with an explicit linear equation involving six amino acids. Tyrosine, in particular, was identified as the key amino acid in controlling BA, as it had the strongest correlation with BA and was consistently identified as the most important amino acid in feature importance studies. Glycine and serine were identified as the next two most important amino acids in predicting BA. The results from this study further our understanding of PPIs and can be used to make improved predictions of BA, giving them implications for drug design and screening in the pharmaceutical industry.

4.
ACS Appl Mater Interfaces ; 16(2): 2041-2057, 2024 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-38173420

RESUMO

Cancer is the second leading cause of death attributed to disease worldwide. Current standard detection methods often rely on a single cancer marker, which can lead to inaccurate results, including false negatives, and an inability to detect multiple cancers simultaneously. Here, we developed a multiplex method that can effectively detect and classify surface proteins associated with three distinct types of breast cancer by utilizing gap-enhanced Raman scattering nanotags and machine learning algorithm. We synthesized anisotropic magnetic core-gold shell gap-enhanced Raman nanotags incorporating three different Raman reporters. These multicolor Raman nanotags were employed to distinguish specific surface protein markers in breast cancer cells. The acquired signals were deconvoluted and analyzed using classical least-squares regression to generate a surface protein profile and characterize the breast cancer cells. Furthermore, computational data obtained via finite-difference time-domain and discrete dipole approximation showed the amplification of the electric fields within the gap region due to plasmonic coupling between the two gold layers. Finally, a random forest classifier achieved an impressive classification and profiling accuracy of 93.9%, enabling effective distinguishing between the three different types of breast cancer cell lines in a mixed solution. With the combination of immunomagnetic multiplex target specificity and separation, gap-enhancement Raman nanotags, and machine learning, our method provides an accurate and integrated platform to profile and classify different cancer cells, giving implications for identification of the origin of circulating tumor cells in the blood system.


Assuntos
Neoplasias da Mama , Nanopartículas Metálicas , Humanos , Feminino , Análise Espectral Raman/métodos , Neoplasias da Mama/diagnóstico , Ouro , Algoritmos , Proteínas de Membrana , Fenômenos Magnéticos
6.
Aust J Rural Health ; 21(6): 343-9, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24299440

RESUMO

OBJECTIVES: To improve osteoporosis (OSP) management following minimal trauma fracture (MTF) with few additional resources. DESIGN: Population intervention with serial cross-sectional analysis. SETTING: Regional setting involving primary care, base hospital and private hospital. PARTICIPANTS: Patients with MTF. INTERVENTION: A 'Fracture Card' prompting OSP management was provided to all patients post-MTF. Patients were encouraged to attend their general practitioner (GP) with this to discuss bone health issues. The 2-year intervention was supported by a public health education campaign. MAIN OUTCOME MEASURES: Number of (i) serum 25-OH vitamin D assays, (ii) dual-energy X-ray absorptiometry (DXA) scans, and (iii) new Pharmaceutical Benefits Scheme (PBS)-subsidised prescriptions for bone protective therapy (bisphosphonates, raloxifene, strontium, teriparatide, denosumab). RESULTS: The number of serum 25-OH vitamin D assays ordered in Coffs Harbour increased from 329 ± 15 per month (July 2009-June 2010) to 568 ± 21 (July 2010-June 2012; P < 0.001). The number of DXA scans performed per month increased from 192 ± 14 (July 2009-June 2010) to 296 ± 12 (July 2010-June 2012; P < 0.001). There was no difference in the number of new PBS-subsidised prescriptions for bone protective therapy in the Coffs statistical subdivision over that time (176 ± 3.8 per month, July 2009-June 2010 versus 180 ± 3.5, July 2010-June 2012, P > 0.05). CONCLUSIONS: The intervention was associated with an increased number of 25-OH vitamin D assays and DXA scans but not with more prescriptions for bone protective therapy. This suggests that a public health education campaign and provision of a 'prompt' for GPs was only partially successful at improving OSP management post-MTF. This has driven establishment of a Fracture Liaison Service.


Assuntos
Absorciometria de Fóton/estatística & dados numéricos , Conservadores da Densidade Óssea/uso terapêutico , Fraturas Ósseas/terapia , Fidelidade a Diretrizes , Osteoporose/terapia , Vitamina D/sangue , Idoso , Estudos Transversais , Feminino , Fraturas Ósseas/etiologia , Humanos , Masculino , Pessoa de Meia-Idade , Osteoporose/complicações , Osteoporose/diagnóstico , Educação de Pacientes como Assunto
7.
Nanomaterials (Basel) ; 13(3)2023 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-36770486

RESUMO

Extracellular vesicles (EVs) have emerged as a novel resource of biomarkers for cancer and certain other diseases. Probing EVs in body fluids has become of major interest in the past decade in the development of a new-generation liquid biopsy for cancer diagnosis and monitoring. However, sensitive and specific molecular detection and analysis are challenging, due to the small size of EVs, low amount of antigens on individual EVs, and the complex biofluid matrix. Nanomaterials have been widely used in the technological development of protein and nucleic acid-based EV detection and analysis, owing to the unique structure and functional properties of materials at the nanometer scale. In this review, we summarize various nanomaterial-based analytical technologies for molecular EV detection and analysis. We discuss these technologies based on the major types of nanomaterials, including plasmonic, fluorescent, magnetic, organic, carbon-based, and certain other nanostructures. For each type of nanomaterial, functional properties are briefly described, followed by the applications of the nanomaterials for EV biomarker detection, profiling, and analysis in terms of detection mechanisms.

8.
Spine Deform ; 11(5): 1177-1187, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37074517

RESUMO

PURPOSE: Adult Spinal Deformity (ASD) includes a spectrum of spinal conditions that can be associated with significant pain and loss of function. While 3-column osteotomies have been the procedures of choice for ASD patients, there is also a substantial risk for complications. The prognostic value of the modified 5-item frailty index (mFI-5) for these procedures has not yet been studied. The goal of this study is to evaluate the association of mFI-5 with 30-day morbidity, readmission, and reoperation following a 3-column osteotomy. METHODS: The National Surgical Quality Improvement Program (NSQIP) database was queried to identify patients undergoing 3-Column Osteotomy procedures from 2011-2019. Multivariate modeling was utilized to assess mFI-5 and other demographic, comorbidity, laboratory, and perioperative variables as independent predictors of morbidity, readmission, and reoperation. RESULTS: N = 971. Multivariate analysis revealed that mFI-5 = 1 (OR = 1.62, p = 0.015) and mFI-5 ≥ 2 (OR = 2.17, p = 0.004) were significant independent predictors of morbidity. mFI-5 ≥ 2 was a significant independent predictor of readmission (OR = 2.16, p = 0.022) while mFI-5 = 1 was not a significant predictor of readmission (p = 0.053). Frailty did not predict reoperation. CONCLUSION: Frailty as defined by mFI-5 strongly and independently predicted increased odds of postoperative morbidity for patients undergoing 3-column osteotomy as surgical intervention for ASD. Only mFI-5 ≥ 2 was a significant independent predictor of readmission, while frailty did not predict reoperation. Other variables independently predicted increased and decreased odds of postoperative morbidity, readmission, and reoperation. LEVEL OF EVIDENCE: III.


Assuntos
Fragilidade , Adulto , Humanos , Fragilidade/complicações , Fragilidade/epidemiologia , Morbidade , Reoperação , Bases de Dados Factuais , Osteotomia/efeitos adversos
9.
ACS Appl Mater Interfaces ; 15(2): 2679-2692, 2023 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-36598405

RESUMO

Single vesicle molecular profiling has the potential to transform cancer detection and monitoring by precisely probing cancer-associated extracellular vesicles (EVs) in the presence of normal EVs in body fluids, but it is challenging due to the small EV size, low abundance of antigens on individual vesicles, and a complex biological matrix. Here, we report a facile dual imaging single vesicle technology (DISVT) for surface protein profiling of individual EVs and quantification of target-specific EV subtypes based on direct molecular capture of EVs from diluted biofluids, dual EV-protein fluorescence-light scattering imaging, and fast image analysis using Bash scripts, Python, and ImageJ. Plasmonic gold nanoparticles (AuNPs) were used to label and detect targeted surface protein markers on individual EVs with dark-field light scattering imaging at the single particle level. Monte Carlo calculations estimated that the AuNPs could detect EVs down to 40 nm in diameter. Using the DISVT, we profiled surface protein markers of interest across individual EVs derived from several breast cancer cell lines, which reflected the parental cells. Studies with plasma EVs from healthy donors and breast cancer patients revealed that the DISVT, but not the traditional bulk enzyme-linked immunosorbent assay, detected human epidermal growth factor receptor 2 (HER2)-positive breast cancer at an early stage. The DISVT also precisely differentiated HER2-positive breast cancer from HER2-negative breast cancer. We additionally showed that the amount of tumor-associated EVs was tripled in locally advanced patients compared to that in early-stage patients. These studies suggest that single EV surface protein profiling with DISVT can provide a facile and high-sensitivity method for early cancer detection and quantitative monitoring.


Assuntos
Neoplasias da Mama , Vesículas Extracelulares , Nanopartículas Metálicas , Feminino , Humanos , Antígenos , Neoplasias da Mama/diagnóstico por imagem , Neoplasias da Mama/metabolismo , Vesículas Extracelulares/metabolismo , Ouro/metabolismo , Detecção Precoce de Câncer/métodos
10.
Clocks Sleep ; 4(4): 549-560, 2022 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-36278536

RESUMO

Objective/Background: Phenotyping of non-rapid-eye-movement (NREM) parasomnias is currently poorly undertaken. This study aimed to determine whether there are differences phenotypically among childhood-, adolescent-, and adult-onset NREM parasomnias continuing into and presenting in adulthood. Patients/Methods: A retrospective, cohort study of patients presenting with NREM parasomnia between 2008 and 2019 (n = 307) was conducted. Disorders included sleepwalking (n = 231), night terrors (n = 150), sexualised behaviour in sleep (n = 50), and sleep-related eating disorder (n = 28). Results: Compared to the adult-onset NREM behaviours group, the childhood- and adolescent-onset groups were more likely to have a family history of NREM behaviours (p < 0.001), experience a greater spectrum of NREM disorders (p = 0.001), and report a history of sleep-talking significantly more frequently (p = 0.014). Atopy was most prevalent in the childhood-onset group (p = 0.001). Those with childhood-onset NREM parasomnias were significantly more likely to arouse from N3 sleep on video polysomnography (p = 0.0003). Psychiatric disorders were more likely to be comorbid in the adult-onset group (p = 0.012). A history of trauma coinciding with onset of NREM behaviours was significantly more common in the childhood- and adolescent-onset groups (p < 0.001). Conclusions: Significant differences exist across childhood-, adolescent-, and adult-onset NREM parasomnia presenting in adulthood. This study suggests that adult-onset slow-wave sleep disorders may be confounded by psychiatric disorders resulting in nocturnal sleep disruption and that unresolved traumatic life experiences perpetuate NREM disorders arising in childhood and comprise one of the strongest external risk factors for triggering and perpetuating these disorders in adolescence.

11.
Bioengineering (Basel) ; 9(5)2022 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-35621478

RESUMO

Noble metal nanoparticles have been sought after in cancer nanomedicine during the past two decades, owing to the unique localized surface plasmon resonance that induces strong absorption and scattering properties of the nanoparticles. A popular application of noble metal nanoparticles is photothermal therapy, which destroys cancer cells by heat generated by laser irradiation of the nanoparticles. Gold nanorods have stood out as one of the major types of noble metal nanoparticles for photothermal therapy due to the facile tuning of their optical properties in the tissue penetrative near infrared region, strong photothermal conversion efficiency, and long blood circulation half-life after surface modification with stealthy polymers. In this review, we will summarize the optical properties of gold nanorods and their applications in photothermal therapy. We will also discuss the recent strategies to improve gold nanorod-assisted photothermal therapy through combination with chemotherapy and photodynamic therapy.

12.
Mol Cancer Res ; 20(4): 607-621, 2022 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-34992146

RESUMO

There is a continued need to identify novel therapeutic targets to prevent the mortality associated with prostate cancer. In this context, mitochondrial Rho GTPase 2 (MIRO2) mRNA was upregulated in metastatic prostate cancer compared with localized tumors, and higher MIRO2 levels were correlated with poor patient survival. Using human cell lines that represent androgen-independent or -sensitive prostate cancer, we showed that MIRO2 depletion impaired cell growth, colony formation, and tumor growth in mice. Network analysis of MIRO2's binding partners identified metabolism and cellular responses to extracellular stimuli as top overrepresented pathways. The top hit on our screen, General Control Nonderepressible 1 (GCN1), was overexpressed in prostate cancer, and interacted with MIRO2 in prostate cancer cell lines and in primary prostate cancer cells. Functional analysis of MIRO2 mutations present in patients with prostate cancer led to the identification of MIRO2 159L, which increased GCN1 binding. Importantly, MIRO2 was necessary for efficient GCN1-mediated GCN2 kinase signaling and induction of the transcription factor activating transcription factor 4 (ATF4) levels. Further, MIRO2's effect on regulating prostate cancer cell growth was mediated by ATF4. Finally, levels of activated GCN2 and ATF4 were correlated with MIRO2 expression in prostate cancer xenografts. Both MIRO2 and activated GCN2 levels were higher in hypoxic areas of prostate cancer xenografts. Overall, we propose that targeting the MIRO2-GCN1 axis may be a valuable strategy to halt prostate cancer growth. IMPLICATIONS: MIRO2/GCN1/GCN2 constitute a novel mitochondrial signaling pathway that controls androgen-independent and androgen-sensitive prostate cancer cell growth.


Assuntos
Neoplasias da Próstata , Animais , Humanos , Masculino , Camundongos , Fatores de Alongamento de Peptídeos/genética , Fatores de Alongamento de Peptídeos/metabolismo , Neoplasias da Próstata/genética , Proteínas Serina-Treonina Quinases , Proteínas de Ligação a RNA/metabolismo , Transdução de Sinais , Transativadores/metabolismo
14.
Bioorg Med Chem Lett ; 21(14): 4155-9, 2011 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-21696955

RESUMO

Cyclic nucleotide phosphodiesterases (PDEs) are represented by a large superfamily of enzymes. A series of hydrazone-based inhibitors was synthesized and shown to be novel, potent, and selective against PDE10A. Optimized compounds of this class were efficacious in animal models of schizophrenia and may be useful for the treatment of this disease.


Assuntos
Hidrazonas/química , Inibidores de Fosfodiesterase/química , Diester Fosfórico Hidrolases/química , Quinolinas/química , Animais , Modelos Animais de Doenças , Humanos , Hidrazonas/farmacocinética , Hidrazonas/uso terapêutico , Inibidores de Fosfodiesterase/farmacocinética , Inibidores de Fosfodiesterase/uso terapêutico , Diester Fosfórico Hidrolases/metabolismo , Quinolinas/farmacocinética , Quinolinas/uso terapêutico , Ratos , Esquizofrenia/tratamento farmacológico , Relação Estrutura-Atividade
15.
J Am Chem Soc ; 131(23): 8196-210, 2009 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-19507906

RESUMO

The viability of bridgehead lithiation-substitution of bridged carbonyl compounds has been tested in the laboratory, and the results were rationalized with the aid of a computational study. Lithiation-substitution was found to be possible for ketones, lactones, lactams, and imides having small bridges, including examples having [3.2.1], [3.2.2], [3.3.1], [4.2.1], and [4.3.1] skeletons. Smaller systems, where the sum of the bridging atoms (S) was 5, for example [2.2.1] or [3.1.1] ketones or [2.2.1] lactams, did not undergo controlled bridgehead substitution. Ketones or lactams having a [2.2.2] structure also did not give bridgehead substitution. B3LYP calculations accurately predict this behavior with negative DeltaE(rxn) values being calculated for the successful deprotonations and positive DeltaE(rxn) values being calculated for the unsuccessful ones. NBO calculations were also performed on the anionic deprotonated species, and these show that some structures are best represented as bridgehead enolates and some are best represented as alpha-keto carbanions.


Assuntos
Hidrocarbonetos Aromáticos com Pontes/química , Imidas/química , Cetonas/química , Lactamas/química , Lactonas/química , Lítio/química , Modelos Químicos , Simulação por Computador , Computação Matemática , Estrutura Molecular
16.
Bioorg Med Chem Lett ; 17(23): 6579-83, 2007 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-17931864

RESUMO

A new series of non-peptidic, mono-acid protein tyrosine phosphatase 1B (PTP1B) inhibitors has been identified by structure-based design. Compounds with 2-(indol-3-yl)- and 2-phenyl-3,3,3-trifluoro-2-hydroxypropionic acid core units targeted at the enzyme's primary site and a hydrophobic chlorophenylthiazole extension in its 2 degrees site exhibit 3-60microM IC(50)s for PTP1B inhibition in an Sf9 cell-based assay.


Assuntos
Inibidores Enzimáticos/síntese química , Propionatos/química , Propionatos/classificação , Proteína Tirosina Fosfatase não Receptora Tipo 1/antagonistas & inibidores , Animais , Sítios de Ligação , Linhagem Celular , Inibidores Enzimáticos/classificação , Inibidores Enzimáticos/metabolismo , Ligantes , Propionatos/farmacologia , Proteína Tirosina Fosfatase não Receptora Tipo 1/metabolismo , Spodoptera/citologia
17.
Org Lett ; 5(10): 1673-5, 2003 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-12735749

RESUMO

[reaction: see text] Contrary to expectations, a number of bridged carbonyl compounds undergo facile bridgehead metalation with lithium amide bases. Diketone, lactone, lactam, and imide functions are all demonstrated to participate in this type of "bridgehead enolate" chemistry, leading to a range of substituted products. Meso compounds can also be desymmetrized in very high ee by asymmetric bridgehead metalation.

18.
Cleve Clin J Med ; 70(3): 203-4, 206, 208-9 passim, 2003 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-12678210

RESUMO

Epidemiologic and experimental data suggest that isoflavones have benefits for preventing and treating some prostate disease. Isoflavone supplements may therefore be an important tool for men concerned about prostate disease, such as those with benign prostatic hypertrophy undergoing watchful waiting or those concerned about the potential for prostate cancer. Conclusive proof of a relationship between isoflavones and the prevention and treatment of prostate disease can only come from prospective, randomized, controlled clinical trials.


Assuntos
Suplementos Nutricionais , Isoflavonas/uso terapêutico , Doenças Prostáticas/tratamento farmacológico , Doenças Prostáticas/prevenção & controle , Idoso , Seguimentos , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Satisfação do Paciente , Hiperplasia Prostática/tratamento farmacológico , Hiperplasia Prostática/prevenção & controle , Neoplasias da Próstata/epidemiologia , Neoplasias da Próstata/prevenção & controle , Medição de Risco , Sensibilidade e Especificidade , Resultado do Tratamento
19.
Org Biomol Chem ; 1(12): 2173-86, 2003 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-12945911

RESUMO

The synthesis and directed dihydroxylation of a range of cyclic alkenes was investigated. Both homoallylic alcohols and homoallylic trihaloacetamides were found to be efficient directing groups, giving rise to good to excellent levels of remote asymmetric induction with OsO4-TMEDA. Interestingly, in all cases examined, trifluoroacetamides were found to be superior to trichloroacetamides as directing groups and an argument is presented which rationalises this observation.

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