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1.
Ann Oncol ; 34(5): 477-485, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-36858151

RESUMO

BACKGROUND: The first interim analysis of the phase III, randomized, double-blind, placebo-controlled, multinational TITAN study demonstrated improved overall survival (OS) and radiographic progression-free survival (rPFS) with apalutamide added to ongoing androgen deprivation therapy (ADT) in patients with metastatic castration-sensitive prostate cancer. The final analysis confirmed improvement in OS and other long-term outcomes. We evaluated prostate-specific antigen (PSA) kinetics and the association between PSA decline and outcomes in patients with metastatic castration-sensitive prostate cancer from TITAN. PATIENTS AND METHODS: Patients received apalutamide (240 mg/day) or placebo plus ADT (1 : 1). This post hoc exploratory analysis evaluated PSA kinetics and decline in relation to rPFS (22.7 months' follow-up) and OS, time to PSA progression, and time to castration resistance (44.0 months' follow-up) in patients with or without confirmed PSA decline using a landmark analysis, the Kaplan-Meier method, and Cox proportional hazards model. RESULTS: One thousand and fifty-two patients (apalutamide, 525; placebo, 527) were enrolled. Best confirmed PSA declines (≥50% or ≥90% from baseline or to ≤0.2 ng/ml) were achieved at any time during the study in 90%, 73%, and 68% of apalutamide-treated versus 55%, 29%, and 32% of placebo-treated patients, respectively. By 3 months of apalutamide treatment, best deep PSA decline of ≥90% or to ≤0.2 ng/ml occurred in 59% and 51% of apalutamide- and in 13% and 18% of placebo-treated patients, respectively. Achievement of deep PSA decline at landmark 3 months of apalutamide treatment was associated with longer OS [hazard ratio (HR) 0.35; 95% confidence interval (CI) 0.25-0.48), rPFS (HR 0.44; 95% CI 0.30-0.65), time to PSA progression (HR 0.31; 95% CI 0.22-0.44), and time to castration resistance (HR 0.38; 95% CI 0.27-0.52) compared with no decline (P < 0.0001 for all). Similar results were observed at landmark 6 and 12 months of apalutamide treatment. CONCLUSIONS: Apalutamide plus ADT demonstrated a robust (rapid, deep, and durable) PSA decline that was associated with improved clinical outcomes, including long-term survival.


Assuntos
Antígeno Prostático Específico , Neoplasias de Próstata Resistentes à Castração , Masculino , Humanos , Antagonistas de Androgênios/uso terapêutico , Androgênios/uso terapêutico , Castração
2.
Nanoscale ; 11(5): 2238-2248, 2019 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-30656311

RESUMO

We report a pulsed laser annealing method to convert carbon fibers and nanotubes into diamond fibers at ambient temperature and pressure in air. The conversion of carbon nanofibers and nanotubes into diamond nanofibers involves melting in a super undercooled state using nanosecond laser pulses, and quenching rapidly to convert into phase-pure diamond. The conversion process occurs at ambient temperature and pressure, and can be carried out in air. The structure of diamond fibers has been confirmed by selected-area electron diffraction in transmission electron microscopy, electron-back-scatter-diffraction in high-resolution scanning electron microscopy, all showing characteristic diffraction lines for the diamond structure. The bonding characteristics were determined by Raman spectroscopy with a strong peak near 1332 cm-1, and high-resolution electron-energy-loss spectroscopy in transmission electron microscopy with a characteristic peak at 292 eV for σ* for sp3 bonding and the absence of π* for sp2 bonding. The Raman peak at 1332 cm-1 downshifts to 1321 cm-1 for diamond nanofibers due to the phonon confinement in nanodiamonds. These laser-treated carbon fibers with diamond seeds are used to grow larger diamond crystallites further by using standard hot-filament chemical vapor deposition (HFCVD). We compare these results with those obtained without laser treating the carbon fibers. The details of diamond conversion and HFCVD growth are presented in this paper.

3.
Bioorg Med Chem Lett ; 27(3): 456-459, 2017 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-28038833

RESUMO

Daptomycin is a highly effective lipopeptide antibiotic against Gram-positive pathogens. The presence of (2S, 3R) 3-methyl glutamic acid (mGlu) in daptomycin has been found to be important to the antibacterial activity. However the role of (2S, 3R) mGlu is yet to be revealed. Herein, we reported the syntheses of three daptomycin analogues with (2S, 3R) mGlu substituted by (2S, 3R) methyl glutamine (mGln), dimethyl glutamic acid and (2S, 3R) ethyl glutamic acid (eGlu), respectively, and their antibacterial activities. The detailed synthesis of dimethyl glutamic acid was also reported.


Assuntos
Antibacterianos/química , Daptomicina/análogos & derivados , Ácido Glutâmico/química , Antibacterianos/síntese química , Antibacterianos/farmacologia , Daptomicina/síntese química , Daptomicina/farmacologia , Testes de Sensibilidade Microbiana , Staphylococcus aureus/efeitos dos fármacos , Estereoisomerismo , Relação Estrutura-Atividade
4.
Bioorg Med Chem Lett ; 26(14): 3322-3325, 2016 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-27256913

RESUMO

Irritable bowel diseases (IBD) such as Crohn's disease (CD) and ulcerative colitis (UC) are serious chronic diseases affecting millions of patients worldwide. Studies of human chemokine biology has suggested C-C chemokine receptor 9 (CCR9) may be a key mediator of pro-inflammatory signaling. Discovery of agents that inhibit CCR9 may lead to new therapies for CD and UC patients. Herein we describe the evolution of a high content screening hit (1) into potent inhibitors of CCR9, such as azaindole 12.


Assuntos
Colite Ulcerativa/tratamento farmacológico , Doença de Crohn/tratamento farmacológico , Descoberta de Drogas , Indóis/farmacologia , Receptores CCR/antagonistas & inibidores , Colite Ulcerativa/metabolismo , Doença de Crohn/metabolismo , Relação Dose-Resposta a Droga , Humanos , Indóis/síntese química , Indóis/química , Estrutura Molecular , Receptores CCR/metabolismo , Relação Estrutura-Atividade
5.
Chem Biol Drug Des ; 87(2): 190-9, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26358369

RESUMO

Synthesis of bacterial cell wall peptidoglycan requires glycosyltransferase enzymes that transfer the disaccharide-peptide from lipid II onto the growing glycan chain. The polymerization of the glycan chain precedes cross-linking by penicillin-binding proteins and is essential for growth for key bacterial pathogens. As such, bacterial cell wall glycosyltransferases are an attractive target for antibiotic drug discovery. However, significant challenges to the development of inhibitors for these targets include the development of suitable assays and chemical matter that is suited to the nature of the binding site. We developed glycosyltransferase enzymatic activity and binding assays using the natural products moenomycin and vancomycin as model inhibitors. In addition, we designed a library of disaccharide compounds based on the minimum moenomycin fragment with peptidoglycan glycosyltransferase inhibitory activity and based on a more drug-like and synthetically versatile disaccharide building block. A subset of these disaccharide compounds bound and inhibited the glycosyltransferase enzymes, and these compounds could serve as chemical entry points for antibiotic development.


Assuntos
Proteínas de Bactérias/antagonistas & inibidores , Parede Celular/metabolismo , Peptidoglicano Glicosiltransferase/antagonistas & inibidores , Peptidoglicano/biossíntese , Antibacterianos/química , Antibacterianos/metabolismo , Antibacterianos/farmacologia , Proteínas de Bactérias/metabolismo , Sítios de Ligação , Desenho de Fármacos , Escherichia coli/enzimologia , Concentração Inibidora 50 , Espectroscopia de Ressonância Magnética , Simulação de Acoplamento Molecular , Oligossacarídeos/química , Oligossacarídeos/metabolismo , Oligossacarídeos/farmacologia , Proteínas de Ligação às Penicilinas/antagonistas & inibidores , Proteínas de Ligação às Penicilinas/metabolismo , Peptidoglicano Glicosiltransferase/metabolismo , Estrutura Terciária de Proteína , Staphylococcus aureus/efeitos dos fármacos , Vancomicina/química , Vancomicina/metabolismo , Vancomicina/farmacologia
6.
J Phys Chem C Nanomater Interfaces ; 118(32): 18631-18639, 2014 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-25152799

RESUMO

With the advent of nanobiotechnology, there will be an increase in the interaction between engineered nanomaterials and biomolecules. Nanoconjugates with cells, organelles, and intracellular structures containing DNA, RNA, and proteins establish sequences of nano-bio boundaries that depend on several intricate complex biophysicochemical reactions. Given the complexity of these interactions, and their import in governing life at the molecular level, it is extremely important to begin to understand such nanoparticle-biomaterial association. Here we report a unique method of probing the kinematics between an energy biomolecule, adenosine triphosphate (ATP), and hydrothermally synthesized ZnO nanostructures using micro Raman spectroscopy, X-ray diffraction, and electron microscopy experiments. For the first time we have shown by Raman spectroscopy analysis that the ZnO nanostructures interact strongly with the nitrogen (N7) atom in the adenine ring of the ATP biomolecule. Raman spectroscopy also confirms the importance of nucleotide base NH2 group hydrogen bonding with water molecules and phosphate group ionization and their pH dependence. Calculation of molecular bond force constants from Raman spectroscopy reinforces our experimental data. These data present convincing evidence of pH-dependent interactions between ATP and zinc oxide nanomaterials. Significantly, Raman spectroscopy is able to probe such difficult to study and subtle nano-bio interactions and may be applied to elegantly elucidate the nano-bio interface more generally.

7.
J Org Chem ; 78(11): 5160-71, 2013 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-23692141

RESUMO

A diversity-oriented synthesis (DOS) strategy was developed for the synthesis of stereochemically diverse fused-ring systems containing a pyran moiety. Each scaffold contains an amine and methyl ester for further diversification via amine capping and amide coupling. Scaffold diversity was evaluated in comparison to previously prepared scaffolds by a shape-based principal moments of inertia (PMI) analysis.


Assuntos
Glicosídeos/síntese química , Glicosídeos/química , Conformação Molecular , Piranos/química , Estereoisomerismo
8.
ACS Med Chem Lett ; 2(9): 698-702, 2011 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-21927648

RESUMO

The synthesis of a stereochemically diverse library of medium-sized rings accessible via a 'build/couple/pair' strategy is described. Key aspects of the synthesis include S(N)Ar cycloetherification of a linear amine template to afford eight stereoisomeric 8-membered lactams and subsequent solid-phase diversification of these scaffolds to yield a 6488-membered library. Screening of this compound collection in a cell-based assay for the suppression of cytokine-induced beta-cell apoptosis resulted in the identification of a small-molecule suppressor capable of restoring glucose-stimulated insulin secretion in a rat beta-cell line. The presence of all stereoisomers in the screening collection enabled preliminary determination of the structural and stereochemical requirements for cellular activity, while efficient follow-up chemistry afforded BRD-0476 (probe ML187), which had an approximately three-fold increase in activity. These results demonstrate the utility of diversity-oriented synthesis to probe discovery using cell-based screening, and the importance of including stereochemical diversity in screening collections for the development of stereo/structure-activity relationships.

9.
Tetrahedron ; 67(34): 6131-6137, 2011 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-21822337

RESUMO

Orthogonally protected chiral ß-hydroxy-γ-amino acids can be accessed in >100 g quantities from readily available starting materials and reagents in 3-4 steps. These chiral synthons contain two adjacent stereocenters along with suitably protected functional groups (O-TBS, N-Boc) for downstream reactivity. Implementation of two existing aldol technologies allows rapid access to all possible stereoisomers of 1. The guiding principles during reaction optimization were reaction scalability and operational efficiency. Conversion of the amino acids to a variety of chiral building blocks in 1-2 steps demonstrates their synthetic utility.

10.
J Org Chem ; 76(6): 1898-901, 2011 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-21341742

RESUMO

All stereoisomers of a highly functionalized 2,3-unsaturated C-glycoside can be accessed in 10-100 g quantities from readily available starting materials and reagents in 3-7 steps. These chiral scaffolds contain three stereogenic centers along with orthogonally protected functional groups for downstream reactivity.


Assuntos
Glicosídeos/química , Glicosídeos/síntese química , Indicadores e Reagentes/química , Estereoisomerismo
11.
J Am Chem Soc ; 132(47): 16962-76, 2010 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-21067169

RESUMO

An aldol-based build/couple/pair (B/C/P) strategy was applied to generate a collection of stereochemically and skeletally diverse small molecules. In the build phase, a series of asymmetric syn- and anti-aldol reactions were performed to produce four stereoisomers of a Boc-protected γ-amino acid. In addition, both stereoisomers of O-PMB-protected alaninol were generated to provide a chiral amine coupling partner. In the couple step, eight stereoisomeric amides were synthesized by coupling the chiral acid and amine building blocks. The amides were subsequently reduced to generate the corresponding secondary amines. In the pair phase, three different reactions were employed to enable intramolecular ring-forming processes: nucleophilic aromatic substitution (S(N)Ar), Huisgen [3+2] cycloaddition, and ring-closing metathesis (RCM). Despite some stereochemical dependencies, the ring-forming reactions were optimized to proceed with good to excellent yields, providing a variety of skeletons ranging in size from 8- to 14-membered rings. Scaffolds resulting from the RCM pairing reaction were diversified on the solid phase to yield a 14 400-membered library of macrolactams. Screening of this library led to the discovery of a novel class of histone deacetylase inhibitors, which display mixed enzyme inhibition, and led to increased levels of acetylation in a primary mouse neuron culture. The development of stereo-structure/activity relationships was made possible by screening all 16 stereoisomers of the macrolactams produced through the aldol-based B/C/P strategy.


Assuntos
Aldeídos/química , Descoberta de Drogas/métodos , Inibidores de Histona Desacetilases/síntese química , Inibidores de Histona Desacetilases/farmacologia , Histona Desacetilases/metabolismo , Compostos Macrocíclicos/síntese química , Compostos Macrocíclicos/farmacologia , Animais , Produtos Biológicos/síntese química , Produtos Biológicos/química , Produtos Biológicos/farmacologia , Avaliação Pré-Clínica de Medicamentos , Inibidores de Histona Desacetilases/química , Compostos Macrocíclicos/química , Camundongos , Modelos Moleculares , Conformação Molecular , Estereoisomerismo , Especificidade por Substrato
12.
Neurology ; 74(18): 1416-23, 2010 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-20439843

RESUMO

OBJECTIVES: Cholinergic projections to cerebral cortical and subcortical regions are decreased in Parkinson disease (PD), but not evaluated in the parkinsonian syndromes of multiple system atrophy (MSA-P) and progressive supranuclear palsy (PSP). We studied cholinergic innervation in these disorders as compared to age-appropriate normal control subjects. METHODS: We used PET with [(11)C]PMP to measure acetylcholinesterase (AChE) activity in multiple cerebral cortical and subcortical regions. We studied 22 normal controls, 12 patients with PD, 13 patients with MSA-P, and 4 patients with PSP. RESULTS: We found significantly decreased AChE activity in most cerebral cortical regions in PD and MSA-P, and a similar but nonsignificant decrease in PSP. No differences were found between PD and MSA-P. Significantly decreased AChE activity was found in PD in striatum, cerebellum, and thalamus, with a marginally significant decrease in mesencephalon and no change in pons. Significantly greater declines in AChE activity in all subcortical regions were seen in MSA-P and PSP vs in PD. Decreased AChE activity in brainstem and cerebellum of all 3 disorders correlated with disturbances of balance and gait. CONCLUSIONS: Cerebral cortical cholinergic activity is decreased to a similar level in Parkinson disease (PD), parkinsonian syndromes of multiple system atrophy (MSA-P), and progressive supranuclear palsy (PSP) as compared to normal controls. Subcortical cholinergic activity is significantly more decreased in MSA-P and PSP than in PD. The more substantial decrease reflects greater impairment in the pontine cholinergic group, which is important in motor activity, particularly gait. These differences may account for the greater gait disturbances in the early stages of MSA-P and PSP than in PD.


Assuntos
Acetilcolinesterase/metabolismo , Atrofia de Múltiplos Sistemas/diagnóstico por imagem , Atrofia de Múltiplos Sistemas/fisiopatologia , Transtornos Parkinsonianos/diagnóstico por imagem , Transtornos Parkinsonianos/fisiopatologia , Paralisia Supranuclear Progressiva/diagnóstico por imagem , Paralisia Supranuclear Progressiva/fisiopatologia , Acetilcolina/metabolismo , Idoso , Idoso de 80 Anos ou mais , Encéfalo/anatomia & histologia , Encéfalo/enzimologia , Encéfalo/patologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Atrofia de Múltiplos Sistemas/patologia , Vias Neurais/anatomia & histologia , Vias Neurais/patologia , Vias Neurais/fisiologia , Vias Neurais/fisiopatologia , Transtornos Parkinsonianos/patologia , Tomografia por Emissão de Pósitrons , Traçadores Radioativos , Paralisia Supranuclear Progressiva/patologia
13.
Int J Clin Pract ; 64(2): 160-8, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19929980

RESUMO

AIMS: Intervention studies have shown that angiotensin receptor blockers (ARB) may reduce the incidence of type 2 diabetes mellitus. It is currently unclear whether short-term therapy with ARBs affects metabolic parameters. METHODS: i-RESPOND, a randomised, controlled, multicentre, double-blind study evaluated the effect of 16 weeks of irbesartan vs. hydrochlorothiazide (HCTZ) on insulin resistance as well as on lipid and inflammatory parameters in hypertensive subjects with metabolic syndrome. Patients received irbesartan (150 mg/d; n = 211) or HCTZ (12.5 mg/d; n = 215), titrated to 300 mg/day and 25 mg/day respectively. In a second part of the study (weeks 16-28), patients initially randomised to irbesartan received additional HCTZ and vice versa. RESULTS: At week 16 both irbesartan and HCTZ had no effect on insulin resistance measured by the Matzuda index and beta-cell function. Similarly, in the second part of the study (week 16-28) no differences between irbesartan and HCTZ with respect to glucose metabolism were observed. However, irbesartan induced beneficial changes in high-sensitivity-C-reactive protein (hs-CRP) (irbesartan: -5.5 +/- 5.2%; HCTZ + 19.9 +/- 6.5%, p = 0.0024) and in urinary albumin/creatinine ratio (ACR) (irbesartan: -13%; HCTZ + 9%; p = 0.0041) compared with HCTZ despite a similar decrease in blood pressure in both treatment groups. Irbesartan and HCTZ were well tolerated and adverse events were comparable. CONCLUSION: Irbesartan did not show significant favourable effects on insulin resistance compared with HCTZ in this study; however, may have beneficial effects on inflammation and microalbuminuria in hypertensive patients with metabolic syndrome.


Assuntos
Anti-Hipertensivos/uso terapêutico , Compostos de Bifenilo/uso terapêutico , Diabetes Mellitus Tipo 2/tratamento farmacológico , Hipertensão/tratamento farmacológico , Resistência à Insulina/fisiologia , Síndrome Metabólica/tratamento farmacológico , Tetrazóis/uso terapêutico , Adulto , Idoso , Análise de Variância , Diabetes Mellitus Tipo 2/sangue , Método Duplo-Cego , Feminino , Humanos , Hipertensão/sangue , Irbesartana , Lipídeos/sangue , Masculino , Síndrome Metabólica/sangue , Pessoa de Meia-Idade , Fatores de Risco , Resultado do Tratamento , Adulto Jovem
14.
J Org Chem ; 73(10): 3754-8, 2008 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-18416578

RESUMO

A library of eight 5-F(2)-isoprostanes was prepared through a ring-opening metathesis/cross-metathesis protocol between functionalized bicyclo[3.2.0]heptenes, ethylene, and alpha,beta-unsaturated ketones. This sequence provided racemic enones in a regio- and stereoselective fashion that could be converted to enantiomerically enriched allylic alcohols through a catalyst-controlled asymmetric reduction. Completion of the sidechains, followed by global deprotection, resulted in a stereodivergent route to eight enantiomerically enriched 5-F(2)-isoprostanes. Overall, the synthesis of this library of known and anticipated lipid oxidation metabolites was achieved in 10 steps from commercially available 4-hydroxy-2-cyclopentenone.


Assuntos
Isoprostanos/síntese química , Isoprostanos/química , Conformação Molecular , Estereoisomerismo
15.
J Hum Hypertens ; 22(4): 266-74, 2008 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-17928878

RESUMO

This prospective, double-blind, parallel-group study randomized patients with moderate hypertension (seated systolic blood pressure (SeSBP) 160-179 mm Hg when seated diastolic blood pressure (SeDBP) <110 mm Hg; or SeDBP 100-109 mm Hg when SeSBP <180 mm Hg) 3:1:1 to treatment with irbesartan 300 mg/hydrochlorothiazide (HCTZ) 25 mg combination therapy (n=328), irbesartan 300 mg monotherapy (n=106) or HCTZ monotherapy 25 mg (n=104). Treatment was initiated at half dose, with forced titration to full dose after two weeks followed by ten further weeks' treatment. The primary efficacy variable was the mean reduction in SeSBP from baseline to week 8. Baseline characteristics were similar between groups, with mean baseline blood pressure approximately 162/98 mm Hg; the mean age was 55 years. At week 8 there was a reduction in SeSBP of 27.1 mm Hg with irbesartan/HCTZ, compared with 22.1 mm Hg with irbesartan monotherapy (P=0.0016) and 15.7 mm Hg with HCTZ (P<0.0001). Both the rate of decline and the total degree of decline achieved were greatest with irbesartan/HCTZ and least with HCTZ. A significantly greater percentage of patients reached a treatment goal of SeSBP <140 mm Hg and SeDBP <90 mm Hg by week 8 with irbesartan/HCTZ (53.4%), compared with irbesartan (40.6%; P=0.0254) and HCTZ (20.2%; P<0.0001) alone. Treatment was well tolerated in all three-treatment groups with a slight increase in adverse events in the combination therapy group. In conclusion, irbesartan/HCTZ (300/25 mg) is well tolerated and achieves rapid and sustained reductions in both systolic blood pressure and diastolic blood pressure in patients with moderate hypertension.


Assuntos
Bloqueadores do Receptor Tipo 1 de Angiotensina II/uso terapêutico , Compostos de Bifenilo/uso terapêutico , Pressão Sanguínea/fisiologia , Diuréticos/uso terapêutico , Hidroclorotiazida/uso terapêutico , Hipertensão/tratamento farmacológico , Tetrazóis/uso terapêutico , Adulto , Idoso , Angiotensina II , Pressão Sanguínea/efeitos dos fármacos , Método Duplo-Cego , Quimioterapia Combinada , Feminino , Seguimentos , Humanos , Hipertensão/fisiopatologia , Irbesartana , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Resultado do Tratamento
16.
Nanotechnology ; 19(27): 275705, 2008 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-21828717

RESUMO

An activated-carbon (AC) assisted route is developed to synthesize a ZnO nanoparticle network. The route involves simple addition of AC to the solution containing the zinc salt and finally removing them by burning at higher temperature to form a sponge-like porous ZnO nanoparticles. The surface area measurements show that AC-assisted ZnO nanoparticles (AC-ZnO) have a higher surface area than those synthesized without AC (B-ZnO), which is further confirmed by the field emission scanning electron microscope (FESEM) and high resolution transmission electron microscope (HRTEM) images. Ultraviolet (UV) absorbance results show that the optical quality remains almost unchanged for both types of nanoparticles. Enhanced and faster UV photosensitivity has been observed for the AC-ZnO. The change in the UV photosensing properties demonstrated here provides a new approach to synthesizing other high surface area materials for novel physical and chemical properties.

17.
J Am Chem Soc ; 123(4): 691-6, 2001 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-11456582

RESUMO

Novel open framework molecular sieves, titanium(IV) phosphates named, i.e., TCM-7 and -8 (Toyota Composite Materials, numbers 7 and 8), with new mesoporous cationic framework topologies obtained by using both cationic and anionic surfactants are reported. The (31)P MAS NMR, UV-visible absorption, and XANES data suggest the tetrahedral state of P and Ti, and stabilization of the tetrahedral state of Ti in TCM-7/8 is due to the incorporation of phosphorus (at Ti/P = 1:1) vis-à-vis the most stable octahedral state of Ti in the pure mesoporous TiO(2). Mesoporous TCM-7 and -8 show anion exchange capacity due to the framework phosphonium cation and cation exchange capacity due to defective P-OH groups. The high catalytic activity in the liquid-phase partial oxidation of cyclohexene with a dilute H(2)O(2) oxidant supports the tetrahedral coordination of Ti in these materials.

18.
J Allergy Clin Immunol ; 103(5 Pt 1): 749-55, 1999 May.
Artigo em Inglês | MEDLINE | ID: mdl-10329805

RESUMO

BACKGROUND: Isocyanates are a frequent cause of occupational asthma and can also induce hypersensitivity pneumonitis. OBJECTIVES: It is still unclear whether antibodies to diphenylmethane diisocyanate (MDI), which are elicited in some subjects with these conditions, are specific for this type of isocyanate. Moreover, preparation of conjugates to human serum albumin (HSA) with the polymeric formulation rather than monomeric MDI might result in improved detection of antibodies. METHODS: We addressed these issues by testing the sera of 13 subjects with asthma (n = 12) and hypersensitivity pneumonitis (n = 1) induced by MDI (n = 4 or 5, see below) by comparing them with sera obtained from subjects with occupational asthma caused by toluene diisocyanate (TDI; n = 5) and hexamethylene diisocyanate (HDI; n = 2). Conjugate preparations were compared by using SDS-PAGE, absorbance spectral analysis, and isolectric focusing. Immunologic screening was done by ELISA. RESULTS: Specific IgG antibodies that recognize MDI-HSA conjugates were detected in all but 1 of the MDI-exposed workers and could not be found in TDI-exposed and HDI-exposed workers. The levels of specific IgG antibodies were more elevated when tested against the HSA conjugates formed with polymeric MDI compared with the HSA conjugates formed with monomeric MDI. CONCLUSION: This study shows that specific IgG antibodies to MDI appear to be specific for MDI without cross-reactivity with TDI and HDI and higher by use of polymeric rather than monomeric MDI-HSA test antigens.


Assuntos
Imunoglobulina G/imunologia , Isocianatos/imunologia , Hipersensibilidade Respiratória/imunologia , Tolueno 2,4-Di-Isocianato/efeitos adversos , Adulto , Alérgenos/imunologia , Especificidade de Anticorpos , Asma/imunologia , Reações Cruzadas , Feminino , Volume Expiratório Forçado , Humanos , Masculino , Pessoa de Meia-Idade
19.
J Colloid Interface Sci ; 213(2): 405-411, 1999 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-10222081

RESUMO

Silicalite-1 has been hydrothermally synthesized in a bicontinuous microemulsion of tetraethylenepentamine-sodium bis(2-ethylhexly) sulfosuccinate (AOT)-water system containing fluoride ions. The presence of AOT (an anionic surfactant) has been found to be essential for the formation of Silicalite-1 in bulk tetraethylene pentamine solvent. The tetrahedral binding sites of silicon atom have been confirmed by 29Si magic angle spinning NMR and FT-IR spectra. Thermogravimetric and differential thermal analysis studies on as-synthesized Silicalite-1 and X-ray diffraction pattern for calcined product established their structural stability. The scanning electron micrographs show the twinned and uniform morphology of crystals. The presence of additive (AOT) lengthens the nucleation period and helps to produce a large size crystal of Silicalite-1. Copyright 1999 Academic Press.

20.
Proc Natl Acad Sci U S A ; 95(25): 14711-6, 1998 Dec 08.
Artigo em Inglês | MEDLINE | ID: mdl-9843954

RESUMO

What determines the nuclear organization within a cell and whether this organization itself can impose cellular function within a tissue remains unknown. To explore the relationship between nuclear organization and tissue architecture and function, we used a model of human mammary epithelial cell acinar morphogenesis. When cultured within a reconstituted basement membrane (rBM), HMT-3522 cells form polarized and growth-arrested tissue-like acini with a central lumen and deposit an endogenous BM. We show that rBM-induced morphogenesis is accompanied by relocalization of the nuclear matrix proteins NuMA, splicing factor SRm160, and cell cycle regulator Rb. These proteins had distinct distribution patterns specific for proliferation, growth arrest, and acini formation, whereas the distribution of the nuclear lamina protein, lamin B, remained unchanged. NuMA relocalized to foci, which coalesced into larger assemblies as morphogenesis progressed. Perturbation of histone acetylation in the acini by trichostatin A treatment altered chromatin structure, disrupted NuMA foci, and induced cell proliferation. Moreover, treatment of transiently permeabilized acini with a NuMA antibody led to the disruption of NuMA foci, alteration of histone acetylation, activation of metalloproteases, and breakdown of the endogenous BM. These results experimentally demonstrate a dynamic interaction between the extracellular matrix, nuclear organization, and tissue phenotype. They further show that rather than passively reflecting changes in gene expression, nuclear organization itself can modulate the cellular and tissue phenotype.


Assuntos
Núcleo Celular/ultraestrutura , Matriz Extracelular/ultraestrutura , Morfogênese , Proteínas da Matriz Extracelular/genética , Feminino , Regulação da Expressão Gênica , Humanos , Proteínas Nucleares/genética , Células Tumorais Cultivadas
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