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1.
J Med Chem ; 66(19): 13821-13837, 2023 10 12.
Artigo em Inglês | MEDLINE | ID: mdl-37782298

RESUMO

Histone deacetylase 6 (HDAC6) is an important drug target in oncological and non-oncological diseases. Most available HDAC6 inhibitors (HDAC6i) utilize hydroxamic acids as a zinc-binding group, which limits therapeutic opportunities due to its genotoxic potential. Recently, difluoromethyl-1,3,4-oxadiazoles (DFMOs) were reported as potent and selective HDAC6i but their mode of inhibition remained enigmatic. Herein, we report that DFMOs act as mechanism-based and essentially irreversible HDAC6i. Biochemical data confirm that DFMO 6 is a tight-binding HDAC6i capable of inhibiting HDAC6 via a two-step slow-binding mechanism. Crystallographic and mechanistic experiments suggest that the attack of 6 by the zinc-bound water at the sp2 carbon closest to the difluoromethyl moiety followed by a subsequent ring opening of the oxadiazole yields deprotonated difluoroacetylhydrazide 13 as active species. The strong anionic zinc coordination of 13 and the binding of the difluoromethyl moiety in the P571 pocket finally result in an essentially irreversible inhibition of HDAC6.


Assuntos
Inibidores de Histona Desacetilases , Oxidiazóis , Desacetilase 6 de Histona/metabolismo , Oxidiazóis/farmacologia , Oxidiazóis/química , Inibidores de Histona Desacetilases/farmacologia , Inibidores de Histona Desacetilases/química , Zinco/química , Ácidos Hidroxâmicos/farmacologia , Ácidos Hidroxâmicos/química
2.
J Biol Chem ; 299(10): 105228, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37703993

RESUMO

The enzyme cofactor (R)-lipoic acid plays a critical role in central carbon metabolism due to its catalytic function in the generation of acetyl-CoA, which links glycolysis with the tricarboxylic acid cycle. This cofactor is also essential for the generation of succinyl CoA within the tricarboxylic acid cycle. However, the biological functions of (R)-lipoic acid extend beyond metabolism owing to its facile redox chemistry. Most recently, the reduced form of (R)-lipoic acid, (R)-dihydrolipoic acid, has been shown to inhibit histone deacetylases (HDACs) with selectivity for the inhibition of HDAC6. Here, we report the 2.4 Å-resolution X-ray crystal structure of the complex between (R)-dihydrolipoic acid and HDAC6 catalytic domain 2 from Danio rerio, and we report a dissociation constant (KD) of 350 nM for this complex as determined by isothermal titration calorimetry. The crystal structure illuminates key affinity determinants in the enzyme active site, including thiolate-Zn2+ coordination and S-π interactions in the F583-F643 aromatic crevice. This study provides the first visualization of the connection between HDAC function and the biological response to oxidative stress: the dithiol moiety of (R)-dihydrolipoic acid can serve as a redox-regulated pharmacophore capable of simultaneously targeting the catalytic Zn2+ ion and the aromatic crevice in the active site of HDAC6.


Assuntos
Ácido Tióctico , Animais , Desacetilase 6 de Histona/metabolismo , Ácido Tióctico/metabolismo , Inibidores de Histona Desacetilases/farmacologia , Histona Desacetilases/metabolismo , Peixe-Zebra/metabolismo
3.
Biochemistry ; 62(18): 2689-2699, 2023 09 19.
Artigo em Inglês | MEDLINE | ID: mdl-37624144

RESUMO

Proteomics studies indicate that 10% of proteins in the opportunistic pathogen Acinetobacter baumannii are acetylated, suggesting that lysine acetyltransferases and deacetylases function to maintain and regulate a robust bacterial acetylome. As the first step in exploring these fascinating prokaryotic enzymes, we now report the preparation and characterization of the lysine deacetylase Kdac1. We show that Kdac1 catalyzes the deacetylation of free acetyllysine and acetyllysine tetrapeptide assay substrates, and we also report the X-ray crystal structures of unliganded Kdac1 as well as its complex with the hydroxamate inhibitor Citarinostat. Kdac1 is a tetramer in solution and in the crystal; the crystal structure reveals that the L1 loop functions to stabilize quaternary structure, forming inter-subunit hydrogen bonds and salt bridges around a central arginine residue (R30). Surprisingly, the L1 loop partially blocks entry to the active site, but it is sufficiently flexible to allow for the binding of two Citarinostat molecules in the active site. The L12 loop is also important for maintaining quaternary structure; here, a conserved arginine (R278) accepts hydrogen bonds from the backbone carbonyl groups of residues in an adjacent monomer. Structural comparisons with two other prokaryotic lysine deacetylases reveal conserved residues in the L1 and L12 loops that similarly support tetramer assembly. These studies provide a structural foundation for understanding enzymes that regulate protein function in bacteria through reversible lysine acetylation, serving as a first step in the exploration of these enzymes as possible targets for the development of new antibiotics.


Assuntos
Acinetobacter baumannii , Lisina , Acetilação , Antibacterianos/farmacologia , Arginina
4.
bioRxiv ; 2023 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-37609266

RESUMO

The enzyme cofactor ( R )-lipoic acid plays a critical role in central carbon metabolism due to its catalytic function in the generation of acetyl-CoA, which links glycolysis with the tricarboxylic acid cycle. This cofactor is also essential for the generation of succinyl CoA within the tricarboxylic acid cycle. However, the biological functions of ( R )-lipoic acid extend beyond metabolism owing to its facile redox chemistry. Most recently, the reduced form of ( R )-lipoic acid, ( R )-dihydrolipoic acid, has been shown to inhibit histone deacetylases (HDACs) with selectivity for the inhibition of HDAC6. Here, we report the 2.4 Å-resolution X-ray crystal structure of the HDAC6-( R )-dihydrolipoic acid complex, and we report a dissociation constant (K D ) of 350 nM for this complex as determined by isothermal titration calorimetry. The crystal structure illuminates key affinity determinants in the enzyme active site, including thiolate-Zn 2+ coordination and S-π interactions in the F583-F643 aromatic crevice. This study provides the first visualization of the connection between HDAC function and the biological response to oxidative stress: the dithiol moiety of ( R )-dihydrolipoic acid can serve as a redox-regulated pharmacophore capable of simultaneously targeting the catalytic Zn 2+ ion and the aromatic crevice in the active site of HDAC6.

5.
ACS Chem Biol ; 18(4): 959-968, 2023 04 21.
Artigo em Inglês | MEDLINE | ID: mdl-37027789

RESUMO

Histone deacetylases (HDACs) are essential for the regulation of myriad biological processes, and their aberrant function is implicated in cancer, neurodegeneration, and other diseases. The cytosolic isozyme HDAC6 is unique among the greater family of deacetylases in that it contains two catalytic domains, CD1 and CD2. HDAC6 CD2 is responsible for tubulin deacetylase and tau deacetylase activities, inhibition of which is a key goal as new therapeutic approaches are explored. Of particular interest as HDAC inhibitors are naturally occurring cyclic tetrapeptides such as Trapoxin A or HC Toxin, or the cyclic depsipeptides Largazole and Romidepsin. Even more intriguing are larger, computationally designed macrocyclic peptide inhibitors. Here, we report the 2.0 Å resolution crystal structure of HDAC6 CD2 complexed with macrocyclic octapeptide 1. Comparison with the previously reported structure of the complex with macrocyclic octapeptide 2 reveals that a potent thiolate-zinc interaction made by the unnatural amino acid (S)-2-amino-7-sulfanylheptanoic acid contributes to nanomolar inhibitory potency for each inhibitor. Apart from this zinc-binding residue, octapeptides adopt strikingly different overall conformations and make few direct hydrogen bonds with the protein. Intermolecular interactions are dominated by water-mediated hydrogen bonds; in essence, water molecules appear to cushion the enzyme-octapeptide interface. In view of the broad specificity observed for protein substrates of HDAC6 CD2, we suggest that the binding of macrocyclic octapeptides may mimic certain features of the binding of macromolecular protein substrates.


Assuntos
Desacetilase 6 de Histona , Inibidores de Histona Desacetilases , Histona Desacetilases , Peptídeos Cíclicos , Desacetilase 6 de Histona/química , Inibidores de Histona Desacetilases/farmacologia , Inibidores de Histona Desacetilases/química , Histona Desacetilases/metabolismo , Ligação Proteica , Zinco/metabolismo , Peptídeos Cíclicos/química , Peptídeos Cíclicos/farmacologia
6.
J Med Chem ; 65(22): 15457-15472, 2022 11 24.
Artigo em Inglês | MEDLINE | ID: mdl-36351184

RESUMO

Using a microwave-assisted protocol, we synthesized 16 peptoid-capped HDAC inhibitors (HDACi) with fluorinated linkers and identified two hit compounds. In biochemical and cellular assays, 10h stood out as a potent unselective HDACi with remarkable cytotoxic potential against different therapy-resistant leukemia cell lines. 10h demonstrated prominent antileukemic activity with low cytotoxic activity toward healthy cells. Moreover, 10h exhibited synergistic interactions with the DNA methyltransferase inhibitor decitabine in AML cell lines. The comparison of crystal structures of HDAC6 complexes with 10h and its nonfluorinated counterpart revealed a similar occupation of the L1 loop pocket but slight differences in zinc coordination. The substitution pattern of the acyl residue turned out to be crucial in terms of isoform selectivity. The introduction of an isopropyl group onto the phenyl ring provided the highly HDAC6-selective inhibitor 10p, which demonstrated moderate synergy with decitabine and exceeded the HDAC6 selectivity of tubastatin A.


Assuntos
Antineoplásicos , Leucemia Mieloide Aguda , Peptoides , Humanos , Inibidores de Histona Desacetilases/farmacologia , Inibidores de Histona Desacetilases/uso terapêutico , Inibidores de Histona Desacetilases/química , Desacetilase 6 de Histona , Peptoides/farmacologia , Peptoides/química , Decitabina , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Antineoplásicos/química , Leucemia Mieloide Aguda/tratamento farmacológico , Linhagem Celular Tumoral , Histona Desacetilase 1 , Ácidos Hidroxâmicos/farmacologia , Ácidos Hidroxâmicos/uso terapêutico , Ácidos Hidroxâmicos/química
7.
Biochemistry ; 61(18): 1945-1954, 2022 09 20.
Artigo em Inglês | MEDLINE | ID: mdl-36073962

RESUMO

Bavarostat (EKZ-001) is a selective inhibitor of histone deacetylase 6 (HDAC6) that contains a meta-fluorophenylhydroxamate Zn2+-binding group. The recently determined crystal structure of its complex with HDAC6 from Danio rerio (zebrafish) revealed that the meta-fluoro substituent binds exclusively in an aromatic crevice defined by F583 and F643 rather than being oriented out toward solvent. To explore the binding of inhibitor C-F groups in this fluorophilic crevice, we now report a series of 10 simple fluorophenylhydroxamates bearing one or more fluorine atoms with different substitution patterns. Inhibitory potencies against human and zebrafish HDAC6 range widely from 121 to >30,000 nM. The best inhibitory potency is measured for meta-difluorophenylhydroxamate (5) with IC50 = 121 nM against human HDAC6; the worst inhibitory potencies are measured for ortho-fluorophenylhydroxamate (1) as well as fluorophenylhydroxamates 4, 7, 9, and 10, although there are some variations in activity trends against human and zebrafish HDAC6. These studies show that aromatic ring fluorination at the meta position(s) does not improve inhibitory activity against human HDAC6 relative to the nonfluorinated parent compound phenylhydroxamate (IC50 = 120 nM), but meta-fluorination does not seriously compromise inhibitory activity either. Crystal structures of selected zebrafish HDAC6-fluorophenylhydroxamate complexes reveal that the fluoroaromatic ring is uniformly accommodated in the F583-F643 aromatic crevice, so ring fluorination does not perturb the inhibitor binding conformation. However, hydroxamate-Zn2+ coordination is bidentate for some inhibitors and monodentate for others. These studies will inform design strategies underlying the design of 18F-labeled HDAC6 inhibitors intended for positron emission tomography.


Assuntos
Inibidores de Histona Desacetilases , Peixe-Zebra , Animais , Flúor/metabolismo , Halogenação , Desacetilase 6 de Histona/química , Inibidores de Histona Desacetilases/química , Histona Desacetilases/metabolismo , Humanos , Solventes/metabolismo , Relação Estrutura-Atividade , Peixe-Zebra/metabolismo
8.
Nat Commun ; 12(1): 3384, 2021 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-34099674

RESUMO

Despite recent success in computational design of structured cyclic peptides, de novo design of cyclic peptides that bind to any protein functional site remains difficult. To address this challenge, we develop a computational "anchor extension" methodology for targeting protein interfaces by extending a peptide chain around a non-canonical amino acid residue anchor. To test our approach using a well characterized model system, we design cyclic peptides that inhibit histone deacetylases 2 and 6 (HDAC2 and HDAC6) with enhanced potency compared to the original anchor (IC50 values of 9.1 and 4.4 nM for the best binders compared to 5.4 and 0.6 µM for the anchor, respectively). The HDAC6 inhibitor is among the most potent reported so far. These results highlight the potential for de novo design of high-affinity protein-peptide interfaces, as well as the challenges that remain.


Assuntos
Desenho de Fármacos , Inibidores de Histona Desacetilases/farmacologia , Peptídeos Cíclicos/farmacologia , Relação Estrutura-Atividade , Domínio Catalítico/efeitos dos fármacos , Cristalografia por Raios X , Ensaios Enzimáticos , Histona Desacetilase 2/antagonistas & inibidores , Histona Desacetilase 2/isolamento & purificação , Histona Desacetilase 2/metabolismo , Histona Desacetilase 2/ultraestrutura , Desacetilase 6 de Histona/antagonistas & inibidores , Desacetilase 6 de Histona/genética , Desacetilase 6 de Histona/isolamento & purificação , Desacetilase 6 de Histona/ultraestrutura , Inibidores de Histona Desacetilases/química , Concentração Inibidora 50 , Simulação de Acoplamento Molecular , Ressonância Magnética Nuclear Biomolecular , Biblioteca de Peptídeos , Peptídeos Cíclicos/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Proteínas Recombinantes/ultraestrutura , Proteínas de Peixe-Zebra/genética , Proteínas de Peixe-Zebra/ultraestrutura
9.
J Med Chem ; 64(5): 2691-2704, 2021 03 11.
Artigo em Inglês | MEDLINE | ID: mdl-33576627

RESUMO

Histone deacetylase 6 (HDAC6) is involved in multiple regulatory processes, ranging from cellular stress to intracellular transport. Inhibition of aberrant HDAC6 activity in several cancers and neurological diseases has been shown to be efficacious in both preclinical and clinical studies. While selective HDAC6 targeting has been pursued as an alternative to pan-HDAC drugs, identifying truly selective molecular templates has not been trivial. Herein, we report a structure-activity relationship study yielding TO-317, which potently binds HDAC6 catalytic domain 2 (Ki = 0.7 nM) and inhibits the enzyme function (IC50 = 2 nM). TO-317 exhibits 158-fold selectivity for HDAC6 over other HDAC isozymes by binding the catalytic Zn2+ and, uniquely, making a never seen before direct hydrogen bond with the Zn2+ coordinating residue, His614. This novel structural motif targeting the second-sphere His614 interaction, observed in a 1.84 Å resolution crystal structure with drHDAC6 from zebrafish, can provide new pharmacophores for identifying enthalpically driven, high-affinity, HDAC6-selective inhibitors.


Assuntos
Desacetilase 6 de Histona/antagonistas & inibidores , Inibidores de Histona Desacetilases/farmacologia , Ácidos Hidroxâmicos/farmacologia , Sulfonamidas/farmacologia , Animais , Domínio Catalítico , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Desacetilase 6 de Histona/metabolismo , Inibidores de Histona Desacetilases/síntese química , Inibidores de Histona Desacetilases/metabolismo , Inibidores de Histona Desacetilases/farmacocinética , Humanos , Ácidos Hidroxâmicos/síntese química , Ácidos Hidroxâmicos/metabolismo , Ácidos Hidroxâmicos/farmacocinética , Masculino , Camundongos Endogâmicos BALB C , Simulação de Acoplamento Molecular , Estrutura Molecular , Ligação Proteica , Relação Estrutura-Atividade , Sulfonamidas/síntese química , Sulfonamidas/metabolismo , Sulfonamidas/farmacocinética , Peixe-Zebra , Proteínas de Peixe-Zebra/antagonistas & inibidores , Proteínas de Peixe-Zebra/metabolismo
10.
J Struct Biol ; 213(1): 107681, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33316326

RESUMO

Cornelia de Lange Syndrome (CdLS) and associated spectrum disorders are characterized by one or more congenital anomalies including distinctive facial features, upper limb abnormalities, intellectual disability, and other symptoms. The molecular genetic basis of CdLS is linked to defects in cohesin, a protein complex that functions in sister chromatid cohesion, chromatin organization, and transcriptional regulation. Histone deacetylase 8 (HDAC8) plays an important role in cohesin function by catalyzing the deacetylation of SMC3, which is required for efficient recycling of the cohesin complex. Missense mutations in HDAC8 have been identified in children diagnosed with CdLS spectrum disorders, and here we outline structure-function relationships for four of these mutations. Specifically, we report the 1.50 Å-resolution structure of the I45T HDAC8-suberoylanilide hydroxamic acid complex, the 1.84 Å-resolution structure of E66D/Y306F HDAC8 complexed with a peptide assay substrate, and the 2.40 Å-resolution structure of G320R HDAC8 complexed with the inhibitor M344. Additionally, we present a computationally generated model of D176G HDAC8. These structures illuminate new structure-function relationships for HDAC8 and highlight the importance of long-range interactions in the protein scaffold that can influence catalytic function.


Assuntos
Síndrome de Cornélia de Lange/genética , Histona Desacetilases/genética , Mutação de Sentido Incorreto/genética , Proteínas Repressoras/genética , Proteínas de Ciclo Celular/genética , Proteínas Cromossômicas não Histona/genética , Humanos , Fenótipo , Coesinas
11.
Sci Rep ; 9(1): 8884, 2019 06 20.
Artigo em Inglês | MEDLINE | ID: mdl-31222068

RESUMO

Human ribosomal proteins play important structural and functional roles in the ribosome and in protein synthesis. An efficient method to recombinantly produce and purify these proteins would enable their full characterisation. However, the production of human ribosomal proteins can be challenging. The only published method about the recombinant production of human ribosomal proteins involved the recovery of proteins from inclusion bodies, a process that is tedious and may lead to significant loss of yield. Herein, we explored the use of different Escherichia coli competent cells and fusion protein tags for the recombinant production of human ribosomal proteins. We found that, by using thioredoxin as a fusion protein, soluble ribosomal protein could be obtained directly from cell lysates, thus leading to an improved method to recombinantly produce these proteins.


Assuntos
Escherichia coli/genética , Proteínas Ribossômicas/biossíntese , Humanos , Proteínas Recombinantes/metabolismo , Proteínas Ribossômicas/metabolismo
12.
Acta Ortop Mex ; 32(1): 44-47, 2018.
Artigo em Espanhol | MEDLINE | ID: mdl-30182546

RESUMO

This is a case report of a 96 year old woman with pain and functional impotence in her left hip after fall. X rays were performed and loosening of the acetabular component was appreciated. After discussion of treatment options, it was decided to cement an acetabular component for a double mobility head. There was a high rate of medical and surgical complications in revision of hip arthroplasty in elderly patients. However, it can also offer important benefits in terms of independence and quality of life and even increase life expectancy in patients with less comorbidity. In our case after six months of follow-up the patient was able to walk alone using a walker. In the literature review, age does not appear as a limit for the surgical indication. Preoperative medical optimization of the patient as well as shorter operative time and blood loss, are important factors for good results of these cases.


Se presenta el caso clínico de una paciente de 96 años con dolor e impotencia funcional en cadera izquierda tras caída. En las radiografías se aprecia un aflojamiento del componente acetabular. Tras la discusión de las opciones de tratamiento se decide intervenirla colocando un cotilo cementado para cabeza de doble movilidad. La revisión de artroplastía en pacientes ancianos tiene un riesgo considerable. No obstante, también puede ofrecer importantes beneficios en términos de independencia y calidad de vida e incluso aumentar la esperanza de vida en aquellos pacientes con menos comorbilidad. En nuestro caso tras seis meses de seguimiento la paciente es capaz de deambular de forma autónoma con andador. En la revisión bibliográfica la edad no figura como límite para la indicación quirúrgica. Una adecuada optimización preoperatoria del paciente así como una cirugía con el menor tiempo quirúrgico y sangrado son factores destacados para la buena evolución de estos casos.


Assuntos
Artroplastia de Quadril , Prótese de Quadril , Reoperação , Acetábulo , Fatores Etários , Idoso de 80 Anos ou mais , Cimentos Ósseos , Feminino , Seguimentos , Humanos , Masculino , Falha de Prótese , Qualidade de Vida
13.
Acta ortop. mex ; 32(1): 44-47, ene.-feb. 2018. graf
Artigo em Espanhol | LILACS | ID: biblio-1019327

RESUMO

Resumen: Se presenta el caso clínico de una paciente de 96 años con dolor e impotencia funcional en cadera izquierda tras caída. En las radiografías se aprecia un aflojamiento del componente acetabular. Tras la discusión de las opciones de tratamiento se decide intervenirla colocando un cotilo cementado para cabeza de doble movilidad. La revisión de artroplastía en pacientes ancianos tiene un riesgo considerable. No obstante, también puede ofrecer importantes beneficios en términos de independencia y calidad de vida e incluso aumentar la esperanza de vida en aquellos pacientes con menos comorbilidad. En nuestro caso tras seis meses de seguimiento la paciente es capaz de deambular de forma autónoma con andador. En la revisión bibliográfica la edad no Figura como límite para la indicación quirúrgica. Una adecuada optimización preoperatoria del paciente así como una cirugía con el menor tiempo quirúrgico y sangrado son factores destacados para la buena evolución de estos casos.


Abstract: This is a case report of a 96 year old woman with pain and functional impotence in her left hip after fall. X rays were performed and loosening of the acetabular component was appreciated. After discussion of treatment options, it was decided to cement an acetabular component for a double mobility head. There was a high rate of medical and surgical complications in revision of hip arthroplasty in elderly patients. However, it can also offer important benefits in terms of independence and quality of life and even increase life expectancy in patients with less comorbidity. In our case after six months of follow-up the patient was able to walk alone using a walker. In the literature review, age does not appear as a limit for the surgical indication. Preoperative medical optimization of the patient as well as shorter operative time and blood loss, are important factors for good results of these cases.


Assuntos
Humanos , Masculino , Feminino , Idoso de 80 Anos ou mais , Reoperação , Artroplastia de Quadril , Prótese de Quadril , Qualidade de Vida , Cimentos Ósseos , Falha de Prótese , Seguimentos , Fatores Etários , Acetábulo
14.
Eur J Radiol Open ; 4: 45-49, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28443292

RESUMO

BACKGROUND: Diffusion weighted magnetic resonance imaging (DWI) provides both functional and anatomical information regarding tumours but can also be used for tumour detection. Today, tumour treatment response in clinical trials is mainly assessed on Computed Tomography (CT) using established criteria. Despite availability of dedicated software, CT still requires significant manual work for selection and measurement in treatment response evaluation of solid tumours. PURPOSE: To compare the maximum diameter of tumour lesions on CT with the corresponding measurements on diffusion weighted images. MATERIALS AND METHODS: In this prospective cohort, metastatic lesions were identified on CT and on DWI in five patients with metastatic renal cell carcinoma before and after three months of treatment with pazopanib. Two radiologists independently measured the same lesions on axial CT images and separately also on axial DWI images. The measurements were compared between CT and DWI with respect to the number of target lesions measured, size of the lesions, size reduction due to treatment and the inter-observer variability. Wilcoxon signed rank test, linear regression and Bland-Altman plots were used for statistical analyses. RESULTS: In this pilot study, there was no significant inter-observer variability in terms of numbers of lesion selected between CT and DWI. A significant reduction of lesion size was observed both for CT and DWI when post-treatment scans were compared to pre-treatment scans. There was no significant difference in measurement of lesion size on both pre- and post treatment scans between CT and DWI (p = 0.099 and p = 0.388 respectively). CONCLUSION: Measurement of the size of metastatic lesions on the basis of axial DWI images are in close agreement with measurement based on conventional axial CT images, the most often employed approach in clinical trials today. The results in this pilot study can be used to estimate sufficient sample size in a larger trial with adequate power, were the results can be confirmed in a wider range of cancers other than renal cell carcinoma.

15.
Rev Esp Cir Ortop Traumatol ; 59(1): 26-35, 2015.
Artigo em Espanhol | MEDLINE | ID: mdl-25088240

RESUMO

OBJECTIVE: The purpose of this study is to assess the need to lock the Gamma 3 nail (Stryker, Mahwah New Jersey USA) distally for intertrochanteric fractures of femur 31-A1 and 31-A2 of the AO. MATERIAL AND METHODS: Details were recorded on a sample of 177 patients with intertrochanteric femoral fractures treated in our hospital by a standard Gamma nail between June 2011 and January 2013. A prospective study was conducted by randomizing patients by year of birth, even numbers with, or odd number without, distal locking, forming two groups of 90 and 87 fractures, respectively. RESULTS: The patients treated with a distal locking nail had an increased incidence of medical complications, a lower incidence of biomechanical complications, and an increase in the fracture collapse compared with the control group, with statistical significance (p < 0.05). It is also observed in the group with distal locking increased transfusion requirement and a higher death rate, with statistically significant differences (p < 0.05), but this significance disappears when adjusting for other patient-related characteristics. CONCLUSIONS: Based on the results found in this work, the use of distal locking screw in the Gamma 3 nails should be restricted to unstable trochanteric fractures after reduction where additional stability to the intramedullary nail is required, and may decrease the risk of complications from use.


Assuntos
Pinos Ortopédicos , Fixação Intramedular de Fraturas/métodos , Fraturas do Quadril/cirurgia , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Seguimentos , Fixação Intramedular de Fraturas/instrumentação , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Resultado do Tratamento
17.
Acta Biomater ; 6(12): 4650-6, 2010 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-20643229

RESUMO

pH-sensitive hydrogels based on methacrylic acid (MAA) and poly(ethylene glycol) macromonomer (PEGMEMA) entrapping diltiazem hydrochloride (DIL·HCl) were synthesized inside soft gelatin capsules for use as a new dosage form for oral drug administration. Different monomer compositions were used to evaluate their swelling and release behavior in two media: at low pH, simulating the acid pH of the stomach, and at pH 7, simulating the higher pH environment of the intestine. Both the swelling process and DIL·HCl release strongly depended on pH and monomer composition. Hydrogels with intermediate compositions showed diminished DIL·HCl release at pH 1.2. This fact was related to the formation of an impermeable outer skin, observed by magnetic resonance imaging (MRI). At pH 7 similar shaped release profiles were found for the four hydrogel compositions under investigation. At this neutral pH slow protonation of the carboxylate groups of MAA led to a swelling front and a dry core, also observed by MRI. As a consequence of this anomalous swelling, release curves exhibited a long period of zero order kinetics. This shows that the system could be a suitable candidate to develop a zero order release dosage form for oral administration of DIL·HCl. The swelling and dissolution processes were analyzed by different mathematical approaches.


Assuntos
Diltiazem/farmacologia , Sistemas de Liberação de Medicamentos/métodos , Gelatina/química , Hidrogéis/química , Cápsulas , Preparações de Ação Retardada , Difusão/efeitos dos fármacos , Diltiazem/química , Concentração de Íons de Hidrogênio/efeitos dos fármacos , Cinética , Espectroscopia de Ressonância Magnética , Metacrilatos/química , Modelos Químicos , Polietilenoglicóis/química , Ácidos Polimetacrílicos/química , Solubilidade/efeitos dos fármacos , Temperatura
18.
J Chemother ; 20(2): 225-32, 2008 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-18467250

RESUMO

The efficacy and safety of intravenous (i.v.) azithromycin followed by the oral form, given in addition to i.v. ampicillin-sulbactam, were evaluated in 151 patients hospitalized due to community-acquired pneumonia (CAP). Azithromycin 500 mg i.v. once daily plus ampicillin/sulbactam 3 g i.v. twice daily were administered for 2-5 days, then followed by oral azithromycin 500 mg once daily plus the same i.v. ampicillin/sulbactam regimen for a total of 7-10 days of treatment. The clinical response at day 14 was defined as cure, improvement or failure (with the addition of relapse at follow-up at day 30). The other efficacy measures included microbiological (eradication, presumed eradication, persistence, relapse, superinfection) and radiological (resolution, improvement, failure) findings, and outcome of signs and symptoms. Adverse events, vital signs and routine laboratory tests were the safety variables. The number and rate of patients with a positive clinical outcome at day 14 (cured + improved) in the intention-to-treat (ITT) analysis (n = 138) were 119 (86.2%), while 118 (87.4%) were cured or improved in the per-protocol population (PP) subset (n = 135). The rate of success at day 14 was slightly lower in the treated population (78.8%), which included all patients discontinued due to any cause. Clinical failures in the ITT population were 19 (13.8%) at day 14 and 1 (0.9%) at day 30, while 4 patients (3.6%) relapsed at day 30. Signs and symptoms of CAP improved from baseline to endpoint. The results in patients with a pathogen isolated at baseline in the cultures of respiratory tract secretions showed that 17 patients (77.3%) had eradication and 5 (22.7%) had presumed eradication (i.e. absence of adequate sputum for culture) at day 14, with no cases of persistence or superinfection. In the X-ray exam at day 30, 96 patients (85.0%) had resolution, 11 (9.7%) had improvement and 4 (3.5%) had failure. Treatment-related adverse events were reported in 10 patients (6.6%) and caused study discontinuation in 5 of them (one case of angioedema and one case of anaphylactic reaction were serious). No abnormal changes from baseline were found in laboratory parameters. Azithromycin i.v. followed by oral form given in addition to i.v. ampicillin/sulbactam was effective and well tolerated in patients with CAP who required hospital care.


Assuntos
Ampicilina/uso terapêutico , Antibacterianos/uso terapêutico , Azitromicina/uso terapêutico , Pneumonia Bacteriana/tratamento farmacológico , Sulbactam/uso terapêutico , Administração Oral , Adolescente , Adulto , Idoso , Ampicilina/administração & dosagem , Antibacterianos/administração & dosagem , Azitromicina/administração & dosagem , Infecções Comunitárias Adquiridas/tratamento farmacológico , Combinação de Medicamentos , Quimioterapia Combinada , Feminino , Humanos , Infusões Intravenosas , Masculino , Pessoa de Meia-Idade , Sulbactam/administração & dosagem
19.
J Chemother ; 20(1): 77-86, 2008 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-18343748

RESUMO

This randomised, open-label, non-inferiority study was designed to demonstrate that a 3-day course of oral azithromycin 1 g once daily was at least as effective as a standard 7-day course of oral amoxicillin-clavulanate 875/125 mg twice daily in the treatment of outpatients with community-acquired pneumonia (Fine class I and II). In total, 267 patients with clinically and radiologically confirmed community-acquired pneumonia were randomly assigned to receive either the azithromycin (n=136) or the amoxicillin-clavulanate (n=131) regimen. At screening, 60/136 (58.8%) and 61/131 (62.9%) respectively had at least one pathogen identified by sputum culture, PCR, or serology. The primary endpoint was the clinical response in the intent-to-treat population at the end of therapy (day 8 to 12). Clinical success rates were 126/136 (92.6%) for azithromycin and 122/131 (93.1%) for amoxicillin-clavulanate (treatment difference: - 0.48%; 95% confidence interval: - 5.66%; 4.69%). Clinical and radiological success rates at follow-up (day 22-26) were consistent with the end of therapy results, no patient reporting clinical relapse. Bacteriological success rates at the end of therapy were 32/35 (91.4%) for azithromycin and 30/33 (90.9%) for amoxicillin-clavulanate (treatment difference: 0.52%; 95% confidence interval - 10.81%; 11.85%). Both treatment regimens were well tolerated: the overall incidence of adverse events was 34/136 (25.0%) for azithromycin and 22/132 (16.7%) for amoxicillin-clavulanate. In both treatment groups, the most commonly reported events were gastrointestinal symptoms. Azithromycin 1g once daily for 3 days is at least as effective as amoxicillin-clavulanate 875/125 mg twice daily for 7 days in the treatment of adult patients with community-acquired pneumonia.


Assuntos
Combinação Amoxicilina e Clavulanato de Potássio/administração & dosagem , Antibacterianos/administração & dosagem , Azitromicina/administração & dosagem , Pneumonia/tratamento farmacológico , Adolescente , Adulto , Idoso , Infecções Comunitárias Adquiridas/tratamento farmacológico , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Resultado do Tratamento
20.
Oncogene ; 27(21): 3066-71, 2008 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-18071318

RESUMO

Neuroblastic tumours are composed of variable proportions of neuroblasts and Schwann cells. Whether both components share a common neoplastic origin is highly debated and discrepant results have been reported about the presence of tumour-related genetic alterations in Schwann cells. We have used X-methylation analysis and array-CGH to investigate contiguous Schwannian and neuroblastic areas in tumours with a nodular pattern. A skewed X inactivation was observed in four out of five stromal components. Interestingly, in these four cases, the X-inactivation profiles of the neuroblastic components were identical to the matched stromal areas. However, whereas all neuroblastic areas displayed chromosomal imbalances, no alteration was found in any Schwann cell components. Similarly, no alteration was observed in a series of 19 tumours with a single stroma-rich component, which occasionally exhibited a skewed X-inactivation pattern (3/17 informative tumours). Altogether, this indicates that most stroma-rich tumours display a polyclonal proliferation and that Schwann cells do not derive from neuroblasts. However, in tumours with both stroma-rich and -poor components, our results suggest that cells from both areas share a common progenitor.


Assuntos
Neuroblastoma/genética , Células de Schwann/patologia , Diferenciação Celular , Metilação de DNA , Humanos , Neuroblastoma/patologia , Inativação do Cromossomo X
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