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1.
Int J Part Ther ; 9(4): 253-260, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37169010

RESUMO

Purpose: After adequate surgical resection, early-stage oral tongue cancer patients can harbor a low risk of local recurrence but remain at risk of regional recurrence. Oral tongue avoidance during adjuvant radiation therapy is an attractive potential treatment strategy to mitigate treatment toxicity. We sought to quantify the dosimetric advantages of this approach and hypothesized that intensity-modulated proton therapy (IMPT) may further reduce organs at risk doses compared with intensity-modulated radiation therapy (IMRT). Materials and Methods: Five patients with oral tongue cancer treated with postoperative radiation therapy from August 2020 to September 2021 were retrospectively reviewed. Novel clinical target volume contours, excluding the oral tongue, were generated while maintaining coverage of bilateral at-risk lymph nodes. Comparison IMRT (X) and IMPT (PBT) plans were generated using standard treatment volumes (control) and avoidance volumes (study) (n = 4 plans/patient). Dosimetric variables for organs at risk were compared using the paired t test. Results: The prescribed dose was 60 Gy in 30 fractions. D95% clinical target volume coverage was similar between X and PBT plans for both control and study clinical target volumes. Comparing control with study plans, both X (58.9 Gy vs 38.3 Gy, P = .007) and PBT (60.2 Gy vs 26.1 Gy, P < .001) decreased the oral cavity dosemean. The pharyngeal constrictor dosemean was also reduced (P < .003). There was no difference between control and study plans for larynx (P = .19), parotid (P = .11), or mandible dose (P = .59). For study plans, PBT significantly reduced oral cavity dosemean (38.3 Gy vs 26.1 Gy, P = .007) and parotid dosemean (23.3 Gy vs 19.3 Gy, P = .03) compared with X. For control plans, there was no difference in oral cavity dosemean using PBT compared with X, but PBT did improve the parotid dosemean (26.6 Gy vs 19.7 Gy, P = .02). Conclusion: This study quantifies the feasibility and dosimetric advantages of oral tongue avoidance while still treating the at-risk lymph nodes for oral tongue cancer. The dosimetric difference between PBT and X was most prominent with an oral tongue-avoidance strategy.

2.
Chem Sci ; 13(21): 6233-6243, 2022 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-35733906

RESUMO

Modulation of N-glycosylation using human Golgi α-mannosidase II (α-hGMII) inhibitors is a potential anticancer approach, but the clinical utility of current α-hGMII inhibitors is limited by their co-inhibition of human lysosomal α-mannosidase (α-hLM), resulting in abnormal storage of oligomannoses. We describe the synthesis and screening of a small library of novel bicyclic iminosugar-based scaffolds, prepared via natural product-inspired combinatorial chemistry (NPICC), which resulted in the identification of a primary α-hGMII inhibitor with 13.5-fold selectivity over α-hLM. Derivatization of this primary inhibitor using computation-guided synthesis (CGS) yielded an advanced α-hGMII inhibitor with nanomolar potency and 106-fold selectivity over α-hLM. In vitro studies demonstrated its N-glycan modulation and inhibitory effect on hepatocellular carcinoma (HCC) cells. In vivo studies confirmed its encouraging anti-HCC activity, without evidence of oligomannose accumulation.

3.
COPD ; 17(1): 34-39, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31965862

RESUMO

The co-existence of chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea (OSA), termed the overlap syndrome (OVS), is associated with adverse outcomes that may be reversed with treatment. However, diagnosis is limited by the apparent need for in-laboratory polysomnography (PSG). WatchPAT is a portable diagnostic device that is validated for the diagnosis of OSA that might represent an attractive tool for the diagnosis of OVS.Subjects with established COPD were recruited from a general population. Subjects underwent PSG and simultaneous recording with WatchPAT. Pulmonary function testing and questionnaires were also performed.A total of 36 subjects were recruited and valid data was obtained on 33 (age 63 ± 7, BMI 28 ± 7, 61% male, FEV1 56 ± 20% predicted). There was no significant difference in the apnea-hypopnea index (AHI) between PSG and WatchPAT (19 ± 20 versus 20 ± 15 events/h; mean difference 2(-2, 5) events/h; p = 0.381). The AHI was not significantly different in rapid eye movement (REM) and non-rapid eye movement (NREM) determined by PSG versus REM and NREM determined by WatchPAT. WatchPAT slightly overestimated total and REM sleep time, and sleep efficiency. The sensitivity of WatchPAT at an AHI cut-off of ≥5, ≥15, and ≥30 events/h for corresponding PSG AHI cut-offs was 95.8, 92.3, and 88.9, respectively; specificity was 55, 65.0, and 95.8, respectively.WatchPAT is able to determine OSA reliably in patients with COPD. The availability of this additional diagnostic modality may lead to improved detection of OVS, which may in turn lead to improved outcomes for a group of COPD patients at high risk of poor outcomes.


Assuntos
Monitorização Ambulatorial , Doença Pulmonar Obstrutiva Crônica/fisiopatologia , Apneia Obstrutiva do Sono/diagnóstico , Dispositivos Eletrônicos Vestíveis , Actigrafia , Idoso , Feminino , Volume Expiratório Forçado , Frequência Cardíaca , Humanos , Masculino , Manometria , Pessoa de Meia-Idade , Oximetria , Polissonografia , Doença Pulmonar Obstrutiva Crônica/complicações , Apneia Obstrutiva do Sono/complicações , Ronco , Inquéritos e Questionários
4.
J Biomed Sci ; 26(1): 97, 2019 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-31861989

RESUMO

BACKGROUND: Dectin-2, which is a C-type lectin, interacts with the house dust mite (HDM) Dermatophagoides pteronyssinus allergen. This study aimed to investigate whether Dectin-2 blockade by antagonistic monoclonal antibodies (MoAbs) attenuates HDM-induced allergic responses. METHODS: Two anti-Dectin-2 MoAbs were generated and validated for specific binding to Dectin-2 Fc fusion protein (Dectin-2.Fc) and inhibition of Dectin-2.Fc/HDM interaction. Patients with asthma exhibiting high titers of anti-D. pteronyssinus IgE were enrolled. Peripheral blood mononuclear cells with depleted CD14+ monocytes were obtained from these patients and co-cultured with autologous monocyte-derived conventional dendritic cells in the presence of D. pteronyssinus or its group 2 allergens (Der p 2). Interleukin (IL)-5 and IL-13 levels in the culture supernatants were determined using ELISA in the presence or absence of anti-Dectin-2 MoAbs. RESULTS: Two MoAbs, 6A4G7 and 17A1D10, showed specific binding to recombinant Dectin-2.Fc and inhibited HDM binding to Dectin-2.Fc. Both anti-Dectin-2 MoAbs inhibited IL-5 and IL-13 production in co-cultures with Der p 2 stimulation in a dose-dependent manner. 6A4G7 and 17A1D10 (3 µg/mL) significantly inhibited Der p 2-induced (3 µg/mL) IL-5 production by 69.7 and 86.4% and IL-13 production by 84.0 and 81.4%, respectively. Moreover, this inhibitory effect of the two MoAbs remained significant in the presence of D. pteronyssinus. CONCLUSIONS: Anti-Dectin-2 MoAbs significantly inhibited HDM-induced allergic responses in vitro and therefore have the potential to become therapeutic agents in mite-induced allergic diseases.


Assuntos
Anticorpos Bloqueadores/imunologia , Asma/imunologia , Citocinas/imunologia , Células Dendríticas/imunologia , Lectinas Tipo C/imunologia , Leucócitos Mononucleares/imunologia , Pyroglyphidae/imunologia , Adulto , Animais , Células Cultivadas , Feminino , Humanos , Masculino , Camundongos , Camundongos Knockout , Pessoa de Meia-Idade , Células Th2
5.
Lung ; 197(4): 459-464, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31089857

RESUMO

PURPOSE: Patients with obstructive sleep apnea (OSA) are at increased risk of cardiovascular and cerebrovascular disease (CVD) but it is unclear who are at greatest risk. We determined whether the inflammatory marker, C-reactive protein (CRP), could be a useful prognostic biomarker. METHODS: Adult patients referred for polysomnography (PSG) with OSA were studied. Serum CRP levels were measured using ELISA the morning after PSG. Validated CV events within 4 years of PSG were ascertained by linking to provincial research datasets. RESULTS: 155 patients with OSA (AHI ≥ 5/h) had CRP measured. Median age was 53 and median AHI was 21/h. 10 patients (7.1%) suffered at least one event, but rates varied substantially by CRP (0/35 patients in the lowest quartile, and 7/39 in the highest CRP quartile). In the unadjusted analysis, patients in the highest CRP quartile (≥ 2.38 mg/L) were significantly more likely to suffer an event (odds ratio = 9.72 (95% CI 2.43-38.84), p = 0.001). CRP continued to be a significant predictor after controlling for multiple confounders. OSA severity and desaturation were not significantly associated with prospective events. CONCLUSIONS: In this small preliminary study, OSA patients with an elevated CRP were significantly more likely to suffer a CVD event in the 4 years after PSG. Although these findings need to be confirmed in larger prospective cohorts, CRP may be useful in risk stratifying OSA patients to guide therapy or to identify patients that might be most appropriate for clinical trials of CVD prevention.


Assuntos
Proteína C-Reativa/análise , Doenças Cardiovasculares/epidemiologia , Transtornos Cerebrovasculares/epidemiologia , Mediadores da Inflamação/sangue , Apneia Obstrutiva do Sono/sangue , Biomarcadores/sangue , Colúmbia Britânica/epidemiologia , Doenças Cardiovasculares/diagnóstico , Transtornos Cerebrovasculares/diagnóstico , Bases de Dados Factuais , Feminino , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Prognóstico , Estudos Prospectivos , Medição de Risco , Fatores de Risco , Apneia Obstrutiva do Sono/diagnóstico , Apneia Obstrutiva do Sono/epidemiologia , Fatores de Tempo , Regulação para Cima
6.
J Am Chem Soc ; 140(8): 2752-2755, 2018 02 28.
Artigo em Inglês | MEDLINE | ID: mdl-29411975

RESUMO

The rise of antibiotic resistance has created a mounting crisis across the globe and an unmet medical need for new antibiotics. As part of our efforts to develop new antibiotics to target the uncharted surface bacterial transglycosylase, we report an affinity-based ligand screen method using penicillin-binding proteins immobilized on beads to selectively isolate the binders from complex natural products. In combination with mass spectrometry and assays with moenomycin A and salicylanilide analogues (1-10) as reference inhibitors, we isolated four potent antibacterials confirmed to be benastatin derivatives (11-13) and albofungin (14). Compounds 11 and 14 were effective antibiotics against a broad-spectrum of Gram-positive and Gram-negative bacteria, including Acinetobacter baumannii, Clostridium difficile, Staphylococcus aureus, and drug-resistant strains with minimum inhibitory concentrations in the submicromolar to nanomolar range.


Assuntos
Antibacterianos/farmacologia , Bambermicinas/farmacologia , Inibidores Enzimáticos/farmacologia , Glicosiltransferases/antagonistas & inibidores , Salicilanilidas/farmacologia , Xantenos/farmacologia , Acinetobacter baumannii/efeitos dos fármacos , Acinetobacter baumannii/enzimologia , Antibacterianos/química , Antibacterianos/isolamento & purificação , Bambermicinas/química , Bambermicinas/isolamento & purificação , Clostridioides difficile/efeitos dos fármacos , Clostridioides difficile/enzimologia , Relação Dose-Resposta a Droga , Avaliação Pré-Clínica de Medicamentos , Inibidores Enzimáticos/química , Inibidores Enzimáticos/isolamento & purificação , Glicosiltransferases/metabolismo , Testes de Sensibilidade Microbiana , Estrutura Molecular , Salicilanilidas/química , Salicilanilidas/isolamento & purificação , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/enzimologia , Relação Estrutura-Atividade , Xantenos/química , Xantenos/isolamento & purificação
7.
Chem Asian J ; 13(6): 686-700, 2018 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-29380519

RESUMO

LecA is a galactose-binding tetrameric lectin from Pseudomonas aeruginosa involved in infection and biofilm formation. The emergent antibiotic resistance of P. aeruginosa has made LecA a promising pharmaceutical target to treat such infections. To develop LecA inhibitors, we exploit the unique helical structure of polyproline peptides to create a scaffold that controls the galactoside positions to fit their binding sites on LecA. With a modular scaffold design, both the galactoside ligands and the inter-ligand distance can be altered conveniently. We prepared scaffolds with spacings of 9, 18, 27, and 36 Šfor ligand conjugation and found that glycopeptides with galactosides ligands three helical turns (27 Å) apart best fit LecA. In addition, we tested different galactose derivatives on the selected scaffold (27 Å) to improve the binding avidity to LecA. The results validate a new multivalent scaffold design and provide useful information for LecA inhibitor development.


Assuntos
Adesinas Bacterianas/metabolismo , Galactosídeos/farmacologia , Peptídeos/farmacologia , Pseudomonas aeruginosa/química , Sítios de Ligação/efeitos dos fármacos , Relação Dose-Resposta a Droga , Desenho de Fármacos , Galactosídeos/síntese química , Galactosídeos/química , Ligantes , Estrutura Molecular , Peptídeos/química , Relação Estrutura-Atividade , Ressonância de Plasmônio de Superfície
8.
Biochemistry ; 56(40): 5417-5427, 2017 10 10.
Artigo em Inglês | MEDLINE | ID: mdl-28872301

RESUMO

Bacteria cell walls contain many repeating glycan structures, such as peptidoglycans, lipopolysaccharides, teichoic acids, and capsular polysaccharides. Their synthesis starts in the cytosol, and they are constructed from a glycan lipid carrier, undecaprenyl phosphate (C55P), which is essential for cell growth and survival. The lipid derivative undecaprenol (C55OH) is predominant in many Gram-positive bacteria but has not been detected in Gram-negative bacteria; its origin and role have thus remained unknown. Recently, a homologue of diacylglycerol kinase (DgkA) in Escherichia coli (E. coli) was demonstrated to be an undecaprenol kinase (UK) in the Gram-positive bacterium Streptococcus mutans (S. mutans). In this study, we found that S. mutans UK was not only an undecaprenol kinase but also a Mg-ADP-dependent undecaprenyl phosphate phosphatase (UpP), catalyzing the hydrolysis of C55P to C55OH and a free inorganic phosphate. Furthermore, the naturally undetectable C55OH was observed in E. coli cells expressing S. mutans dgkA, supporting the phosphatase activity of UK/UpP in vivo. These two activities were indispensable to each other and utilized identical essential residues binding to their substrates, suggesting that both activities share the same active site and might involve a direct phosphoryl transfer mechanism. This study revealed a unique membrane enzyme displaying bifunctional activities determined by substrate binding and C55OH production. The reciprocal conversion of C55P and the undecaprenol pool efficiently regulate cell wall synthesis, especially in Gram-positive bacteria.


Assuntos
Metabolismo dos Lipídeos , Monoéster Fosfórico Hidrolases/metabolismo , Fosfotransferases (Aceptor do Grupo Álcool)/metabolismo , Fosfatos de Poli-Isoprenil/metabolismo , Streptococcus mutans/enzimologia , Difosfato de Adenosina/metabolismo , Modelos Moleculares , Monoéster Fosfórico Hidrolases/química , Fosforilação , Estrutura Secundária de Proteína , Especificidade por Substrato
9.
PLoS One ; 12(2): e0172582, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28235046

RESUMO

United States-based biorepositories are on the cusp of substantial change in regulatory oversight at the same time that they are increasingly including samples and data from large populations, e.g. all patients in healthcare system. It is appropriate to engage stakeholders from these populations in new governance arrangements. We sought to describe community recommendations for biorepository governance and oversight using deliberative community engagement (DCE), a qualitative research method designed to elicit lay perspectives on complex technical issues. We asked for stakeholders to provide input on governance of large biorepositories at the University of California (UC), a public university. We defined state residents as stakeholders and recruited residents from two large metropolitan areas, Los Angeles (LA) and San Francisco (SF). In LA, we recruited English and Spanish speakers; in SF the DCE was conducted in English only. We recruited individuals who had completed the 2009 California Health Interview Survey and were willing to be re-contacted for future studies. Using stratified random sampling (by age, education, race/ethnicity), we contacted 162 potential deliberants of whom 53 agreed to participate and 51 completed the 4-day DCE in June (LA) and September-October (SF), 2013. Each DCE included discussion among deliberants facilitated by a trained staff and simultaneously-translated in LA. Deliberants also received a briefing book describing biorepository operations and regulation. During the final day of the DCE, deliberants voted on governance and oversight recommendations using an audience response system. This paper describes 23 recommendations (of 57 total) that address issues including: educating the public, sharing samples broadly, monitoring researcher behavior, using informative consent procedures, and involving community members in a transparent process of biobank governance. This project demonstrates the feasibility of obtaining meaningful input on biorepository governance from diverse lay stakeholders. Such input should be considered as research institutions respond to changes in biorepository regulation.


Assuntos
Bancos de Espécimes Biológicos/legislação & jurisprudência , Pesquisa Biomédica/legislação & jurisprudência , Participação da Comunidade , Consentimento Livre e Esclarecido/legislação & jurisprudência , Adulto , Idoso , Pesquisa Biomédica/educação , Feminino , Conhecimentos, Atitudes e Prática em Saúde , Inquéritos Epidemiológicos , Humanos , Los Angeles , Masculino , Pessoa de Meia-Idade , Pesquisa Qualitativa , São Francisco , Universidades
10.
Chem Commun (Camb) ; 53(4): 771-774, 2017 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-27999831

RESUMO

Lipid II analogues bearing major modifications on the second sugar (GlcNAc) were synthesized and evaluated for their substrate activity toward TGases. Unexpectedly, N-deacetyled lipid II decreased its activity dramatically, and the C4-axial OH lipid II became an inhibitor (IC50 = 8 µM) with an approximately 14-fold increase in binding affinity toward TGase (25 vs. 27).


Assuntos
Clostridioides difficile/enzimologia , Inibidores Enzimáticos/farmacologia , Escherichia coli/enzimologia , Lipídeos/farmacologia , Peptidoglicano Glicosiltransferase/antagonistas & inibidores , Açúcares/farmacologia , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/química , Lipídeos/química , Peptidoglicano Glicosiltransferase/metabolismo , Relação Estrutura-Atividade , Especificidade por Substrato , Açúcares/síntese química , Açúcares/química
11.
Sci Rep ; 6: 31579, 2016 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-27531195

RESUMO

Systematic structural modifications of the muramic acid, peptide, and nucleotide moieties of Park's nucleotide were performed to investigate the substrate specificity of B. subtilis MraY (MraYBS). It was found that the simplest analogue of Park's nucleotide only bearing the first two amino acids, l-alanine-iso-d-glutamic acid, could function as a MraYBS substrate. Also, the acid group attached to the Cα of iso-d-glutamic acid was found to play an important role for substrate activity. Epimerization of the C4-hydroxyl group of muramic acid and modification at the 5-position of the uracil in Park's nucleotide were both found to dramatically impair their substrate activity. Unexpectedly, structural modifications on the uracil moiety changed the parent molecule from a substrate to an inhibitor, blocking the MraYBS translocation. One unoptimized inhibitor was found to have a Ki value of 4 ± 1 µM against MraYBS, more potent than tunicamycins.


Assuntos
Proteínas de Bactérias/metabolismo , Nucleotídeos/metabolismo , Transferases/metabolismo , Antibacterianos/farmacologia , Bacillus subtilis/efeitos dos fármacos , Proteínas de Bactérias/antagonistas & inibidores , Proteínas de Bactérias/química , Testes de Sensibilidade Microbiana , Conformação de Ácido Nucleico , Nucleotídeos/química , Staphylococcus aureus/efeitos dos fármacos , Especificidade por Substrato , Transferases/antagonistas & inibidores , Transferases/química , Transferases (Outros Grupos de Fosfato Substituídos)
12.
Clin Transl Sci ; 8(4): 362-6, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25581047

RESUMO

Biorepositories, or biobanks, provide researchers with access to biological samples and associated data in support of translational research. Efficient operation and ethical stewardship of biobanks involves coordinated efforts among multiple stakeholders including researchers who manage and use the repository, institutional officials charged with its oversight, and patients and volunteers who contribute samples and data. As advancements in translational research increasingly involve more data derived from larger numbers of diverse samples, the size and governance challenges facing biorepositories have grown. We describe an approach to developing efficient and ethical biobank governance that includes all major stakeholders. This model provides a pathway for addressing the technical and ethical challenges that must be resolved to ensure biorepositories continue to support translational research.


Assuntos
Bancos de Espécimes Biológicos/ética , Pesquisa Biomédica/ética , Humanos , Consentimento Livre e Esclarecido , Universidades
13.
J Am Chem Soc ; 136(48): 16844-53, 2014 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-25371992

RESUMO

Globo H-based therapeutic cancer vaccines have been tested in clinical trials for the treatment of late stage breast, ovarian, and prostate cancers. In this study, we explored Globo H analogue antigens with an attempt to enhance the antigenic properties in vaccine design. The Globo H analogues with modification at the reducing or nonreducing end were synthesized using chemoenzymatic methods, and these modified Globo H antigens were then conjugated with the carrier protein diphtheria toxoid cross-reactive material (CRM) 197 (DT), and combined with a glycolipid C34 as an adjuvant designed to induce a class switch to form the vaccine candidates. After Balb/c mice injection, the immune response was studied by a glycan array and the results showed that modification at the C-6 position of reducing end glucose of Globo H with the fluoro, azido, or phenyl group elicited IgG antibody response to specifically recognize Globo H (GH) and the GH-related epitopes, stage-specific embryonic antigen 3 (SSEA3) (also called Gb5) and stage-specific embryonic antigen 4 (SSEA4). However, only the modification of Globo H with the azido group at the C-6 position of the nonreducing end fucose could elicit a strong IgG immune response. Moreover, the antibodies induced by these vaccines were shown to recognize GH expressing tumor cells (MCF-7) and mediate the complement-dependent cell cytotoxicity against tumor cells. Our data suggest a new potential approach to cancer vaccine development.


Assuntos
Antígenos Glicosídicos Associados a Tumores/química , Antígenos Glicosídicos Associados a Tumores/imunologia , Vacinas Anticâncer/imunologia , Animais , Antígenos Glicosídicos Associados a Tumores/farmacologia , Vacinas Anticâncer/química , Vacinas Anticâncer/farmacologia , Configuração de Carboidratos , Proliferação de Células/efeitos dos fármacos , Humanos , Células MCF-7 , Camundongos , Camundongos Endogâmicos BALB C , Dados de Sequência Molecular , Oxirredução , Relação Estrutura-Atividade
14.
J Posit Psychol ; 9(6): 523-534, 2014 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-25214877

RESUMO

Positive affect predicts improved glycemic control and longevity in adults with type 2 diabetes. We tested DAHLIA, a self-paced online intervention for type 2 diabetes that teaches positive affect skills such as savoring, gratitude, and acts of kindness. Participants (n=49) were randomized to the 5-week DAHLIA course or an emotion-reporting waitlist control. DAHLIA was understood and accepted by participants and showed good retention (78%). At post-intervention, DAHLIA participants showed a significantly greater decrease in depression than controls (-4.3 vs. +0.6 points on the CES-D, p =.05). Secondary analyses found that this effect was considerably stronger in intervention recipients recruited online than those recruited in person. Intervention recipients recruited online also showed significantly increased positive affect, reduced negative affect, and reduced perceived stress. There were no effects on measures of diabetes-specific efficacy or sense of burden, or preliminary measures of health behaviors. This successful feasibility and efficacy trial provides support for a larger trial focusing more specifically on health behavior.

15.
Angew Chem Int Ed Engl ; 53(31): 8060-5, 2014 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-24990652

RESUMO

The emergence of antibiotic resistance has prompted active research in the development of antibiotics with new modes of action. Among all essential bacterial proteins, transglycosylase polymerizes lipid II into peptidoglycan and is one of the most favorable targets because of its vital role in peptidoglycan synthesis. Described in this study is a practical enzymatic method for the synthesis of lipid II, coupled with cofactor regeneration, to give the product in a 50-70% yield. This development depends on two key steps: the overexpression of MraY for the synthesis of lipid I and the use of undecaprenol kinase for the preparation of polyprenol phosphates. This method was further applied to the synthesis of lipid II analogues. It was found that MraY and undecaprenol kinase can accept a wide range of lipids containing various lengths and configurations. The activity of lipid II analogues for bacterial transglycolase was also evaluated.


Assuntos
Enzimas/química , Uridina Difosfato Ácido N-Acetilmurâmico/análogos & derivados , Uridina Difosfato Ácido N-Acetilmurâmico/síntese química
16.
PLoS One ; 8(10): e78904, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24205346

RESUMO

Illness appraisals provide important context to help understand the way individuals cope with chronic illness. In the present study, a qualitative approach to the analysis of HIV diagnosis experience narratives in a sample of 100 people newly diagnosed with HIV revealed five groups that differed in their initial illness appraisals: HIV as Chronic Illness, Concern about Dying, Stigmatization, Threat to Identity, and Other Threats Overshadow HIV. When compared on quantitatively measured depressive mood, the groups differed on level and trajectory over the course of the first year post-diagnosis. Although the experience of living with HIV has changed significantly with the advent of effective Antiretroviral Therapies (ART), there were a number of similarities between the appraisals of this group of participants who were diagnosed post ART and groups who were diagnosed before ART became widely available. Posttest counselors and other HIV service providers should take individual differences in illness appraisals into account in order to help newly HIV-positive clients manage their healthcare and cope adaptively with their diagnosis.


Assuntos
Depressão/complicações , Infecções por HIV/diagnóstico , Infecções por HIV/psicologia , Adaptação Psicológica , Adulto , Doença Crônica/psicologia , Feminino , Infecções por HIV/complicações , Humanos , Masculino , Pessoa de Meia-Idade , Identificação Social , Estereotipagem
17.
J Am Chem Soc ; 135(45): 17078-89, 2013 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-24131464

RESUMO

The emergence of antibiotic resistance has prompted scientists to search for new antibiotics. Transglycosylase (TGase) is an attractive target for new antibiotic discovery due to its location on the outer membrane of bacteria and its essential role in peptidoglycan synthesis. Though there have been a few molecules identified as TGase inhibitors in the past thirty years, none of them have been developed into antibiotics for humans. The slow pace of development is perhaps due to the lack of continuous, quantitative, and high-throughput assay available for the enzyme. Herein, we report a new continuous fluorescent assay based on Förster resonance energy transfer, using lipid II analogues with a dimethylamino-azobenzenesulfonyl quencher in the lipid chain and a coumarin fluorophore in the peptide chain. During the process of transglycosylation, the quencher-appended polyprenol is released and the fluorescence of coumarin can be detected. Using this system, the substrate specificity and affinity of lipid II analogues bearing various numbers and configurations of isoprene units were investigated. Moreover, the inhibition constants of moenomycin and two previously identified small molecules were also determined. In addition, a high-throughput screening using the new assay was conducted to identify potent TGase inhibitors from a 120,000 compound library. This new continuous fluorescent assay not only provides an efficient and convenient way to study TGase activities, but also enables the high-throughput screening of potential TGase inhibitors for antibiotic discovery.


Assuntos
Bactérias/enzimologia , Transferência Ressonante de Energia de Fluorescência/métodos , Peptidoglicano Glicosiltransferase/metabolismo , Cumarínicos/química , Cumarínicos/metabolismo , Ensaios Enzimáticos/métodos , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Peptidoglicano Glicosiltransferase/antagonistas & inibidores , Uridina Difosfato Ácido N-Acetilmurâmico/análogos & derivados , Uridina Difosfato Ácido N-Acetilmurâmico/química , Uridina Difosfato Ácido N-Acetilmurâmico/metabolismo
19.
J Am Chem Soc ; 135(30): 11140-50, 2013 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-23819648

RESUMO

We have successfully developed a [1+2+3] one-pot strategy to synthesize the RM2 antigen hexasaccharide that was proposed to be a prostate tumor antigen. The structure of the synthetic product was verified by NMR analysis and antibody binding assay using a glycan microarray. In addition, the synthetic antigen was conjugated to a mutated diphtheria toxin (DT, CRM197) with different copy numbers and adjuvant combinations to form the vaccine candidates. After vaccination in mice, we used glycan microarrays to monitor their immune response, and the results indicated that, when one molecule of DT was incorporated with 4.7 molecules of RM2 on average (DT-RM4.7) and adjuvanted with the glycolipid C34, the combination exhibited the strongest anti-RM2 IgG titer. Moreover, the induced mouse antibodies mediated effective complement-dependent cytotoxicity (CDC) against the prostate cancer cell line LNCap.


Assuntos
Antígenos Glicosídicos Associados a Tumores/química , Antígenos Glicosídicos Associados a Tumores/imunologia , Vacinas Anticâncer/síntese química , Vacinas Anticâncer/imunologia , Neoplasias da Próstata/imunologia , Adjuvantes Imunológicos/farmacologia , Animais , Antígenos Glicosídicos Associados a Tumores/metabolismo , Vacinas Anticâncer/química , Vacinas Anticâncer/metabolismo , Técnicas de Química Sintética , Toxina Diftérica/genética , Toxina Diftérica/metabolismo , Galactose/metabolismo , Glicolipídeos/metabolismo , Masculino , Camundongos , Mutação , Oligossacarídeos/metabolismo , Vacinas Sintéticas
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