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1.
PLoS One ; 18(6): e0287513, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37352316

RESUMO

The study of the electroencephalogram signals recorded from subjects during an experience is a way to understand the brain processes that underlie their physical and emotional involvement. Such signals have the form of time series, and their analysis could benefit from applying techniques that are specific to this kind of data. Neuroaesthetics, as defined by Zeki in 1999, is the scientific approach to the study of aesthetic perceptions of art, music, or any other experience that can give rise to aesthetic judgments, such as liking or disliking a painting. Starting from a proprietary dataset of 248 trials from 16 subjects exposed to art paintings, using a real ecological context, this paper analyses the application of a novel symbolic machine learning technique, specifically designed to extract information from unstructured data and to express it in form of logical rules. Our purpose is to extract qualitative and quantitative logical rules, to relate the voltage at specific frequencies and in specific electrodes, and that, within the limits of the experiment, may help to understand the brain process that drives liking or disliking experiences in human subjects.


Assuntos
Beleza , Emoções , Humanos , Encéfalo , Estética , Julgamento
2.
Eur Rev Med Pharmacol Sci ; 24(17): 9202-9207, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32965015

RESUMO

OBJECTIVE: SARS-CoV-2 can reportedly exist on inanimate surfaces for a long duration, but there is limited data available from Italian COVID-19 hospital wards, especially for non-intensive care units hosting patients that do not require mechanical ventilation. Identification of the extent of environmental contamination can help in understanding possible virus transmission routes, limit hospital infections and protect healthcare workers. Thus, we investigated virus contamination on surfaces of the acute COVID-19 ward of an Italian hospital. MATERIALS AND METHODS: Ward surfaces, including four points inside and six points outside the patients' rooms were sampled by swabs, seven hours after routine sanitation. To minimize the risk of underestimation of virus detection, two different sensitive molecular methods were used comparatively, and specific internal controls were added to enhance the efficiency of all the analysis steps. RESULTS: SARS-CoV-2 contamination was detected in only three out of all the collected samples, i.e., on two floors and one-bathroom sink, likely reflecting aerosol and saliva contamination, respectively. The overall level of contamination was low, and the floors exhibited a very low level of SARS-CoV-2 presence, evidenced by only one of the two methods used. CONCLUSIONS: The existence of SARS-CoV-2 on hospital surfaces may be limited, although it was reported to persist for a longer duration on surfaces under controlled laboratory conditions. Thus, effective transmission of SARS-CoV-2 by surfaces/fomites within the hospital ward may be a rare event. However, the results highlight the importance of assessing method sensitivity and including controls when investigating low-level virus contamination so as to avoid the risk of underestimation of virus presence.


Assuntos
Betacoronavirus/genética , Infecções por Coronavirus/prevenção & controle , Pandemias/prevenção & controle , Pneumonia Viral/prevenção & controle , RNA Viral/metabolismo , Betacoronavirus/isolamento & purificação , COVID-19 , Infecções por Coronavirus/virologia , Desinfecção , Microbiologia Ambiental , Contaminação de Equipamentos , Hospitais , Humanos , Itália , Pneumonia Viral/virologia , RNA Viral/análise , Reação em Cadeia da Polimerase em Tempo Real , Risco , SARS-CoV-2
3.
Eur Rev Med Pharmacol Sci ; 24(15): 8219-8225, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32767353

RESUMO

OBJECTIVE: At the end of 2019, the Novel Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2), spread rapidly from China to the whole world. Circadian rhythms can play crucial role in the complex interplay between viruses and organisms, and temporized schedules (chronotherapy) have been positively tested in several medical diseases. We aimed to compare the possible effects of a morning vs. evening antiviral administration in COVID patients. PATIENTS AND METHODS: We retrospectively evaluated all patients admitted to COVID internal medicine units with confirmed SARS-CoV-2 infection, and treated with darunavir-ritonavir (single daily dose, for seven days). Age, sex, length of stay (LOS), pharmacological treatment, and timing of antiviral administration (morning or evening), were recorded. Outcome indicators were death or LOS, and laboratory parameters, e.g., variations in C-reactive protein (CRP) levels, ratio of arterial oxygen partial pressure (PaO2, mmHg) to fractional inspired oxygen (FiO2) (PaO2/FiO2), and leucocyte count. RESULTS: The total sample consisted of 151 patients, 33 (21.8%) of whom were selected for antiviral treatment. The mean age was 61.8±18.3 years, 17 (51.5%) were male, and the mean LOS was 13.4±8.6 days. Nine patients (27.3%) had their antiviral administration in the morning, and 24 (72.7%) had antiviral administration in the evening. No fatalities occurred. Despite the extremely limited sample size, morning group subjects showed a significant difference in CRP variation, compared to that in evening group subjects (-65.82±33.26 vs. 83.32±304.89, respectively, p<0.032). No significant differences were found for other parameters. CONCLUSIONS: This report is the first study evaluating temporized morning vs. evening antiviral administration in SARS-CoV-2 patients. The morning regimen was associated with a significant reduction in CRP values. Further confirmations with larger and multicenter samples of patients could reveal novel potentially useful insights.


Assuntos
Antivirais/administração & dosagem , Infecções por Coronavirus/tratamento farmacológico , Darunavir/administração & dosagem , Cronofarmacoterapia , Mortalidade Hospitalar , Tempo de Internação/estatística & dados numéricos , Pneumonia Viral/tratamento farmacológico , Ritonavir/administração & dosagem , Adulto , Idoso , Idoso de 80 Anos ou mais , Betacoronavirus , Gasometria , Proteína C-Reativa , COVID-19 , Infecções por Coronavirus/metabolismo , Quimioterapia Combinada , Humanos , Itália , Contagem de Leucócitos , Pessoa de Meia-Idade , Oxigênio/metabolismo , Pandemias , Pressão Parcial , Pneumonia Viral/metabolismo , Estudos Retrospectivos , SARS-CoV-2 , Tratamento Farmacológico da COVID-19
4.
Pathologica ; 111(3): 98-104, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31748756

RESUMO

We report a singular case of pigmented pagetoid Bowen's disease showing transitional features between extramammary Paget's disease and in situ squamous cell carcinoma.^ieng


Differentiation of pagetoid cutaneous neoplasms can be very challenging on hematoxylin and eosin-stained sections.


Assuntos
Adenocarcinoma in Situ/diagnóstico , Doença de Bowen/diagnóstico , Neoplasias Cutâneas/diagnóstico , Adenocarcinoma in Situ/patologia , Idoso , Doença de Bowen/patologia , Diagnóstico Diferencial , Feminino , Humanos , Neoplasias Cutâneas/patologia
5.
Appl Radiat Isot ; 152: 1-5, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31203094

RESUMO

The goals of this work are to determine the luminescence properties of KYF4 single crystals doped with different concentrations of Ce3+ ions and to evaluate their possible application as a detector of beta radiation. In particular, thermoluminiscence, radioluminiscence and optically stimulated luminescence properties of KYF4: Ce3+ exposed to beta radiation have been studied and very good dosimetric properties have been obtained within the dose range 0.02-20 Gy.

7.
Int J Oral Maxillofac Surg ; 46(12): 1607-1614, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28751181

RESUMO

This retrospective study compared the 5-year clinical and radiographic outcomes of short implants (6 mm) (short group), and standard-length implants (≥9mm) placed after a vertical augmentation with autologous bone blocks (augmentation group), supporting partial fixed prostheses in the posterior mandible. Forty-five partially edentulous patients were enrolled in the study and evaluated after 5 years: 22 (51 implants) in the augmentation group and 23 (46 implants) in the short group. Eight surgical complications occurred in the augmentation group versus none in the short group (P=0.003). One short implant failed before loading and one standard-length implant failed after 4 years because of peri-implantitis (P=1.0). Eight biological and two prosthetic complications occurred in the augmentation group vs. three biological and three prosthetic complications in the short group (P=0.09 and P=1.0, respectively). A mean marginal bone loss of 1.61±1.12mm in the augmentation group and 0.68±0.68mm in the short group was found (P=0.002). Within the limitations of this study, both techniques resulted in successful clinical results after 5 years, but short implants exhibited less surgical complications and marginal bone loss than standard-length implants placed in augmented bone.


Assuntos
Aumento do Rebordo Alveolar/métodos , Implantes Dentários , Mandíbula/patologia , Mandíbula/cirurgia , Atrofia , Tomografia Computadorizada de Feixe Cônico , Planejamento de Prótese Dentária , Prótese Dentária Fixada por Implante , Feminino , Humanos , Masculino , Mandíbula/diagnóstico por imagem , Osteotomia Mandibular , Pessoa de Meia-Idade , Complicações Pós-Operatórias , Estudos Retrospectivos , Resultado do Tratamento
8.
Appl Radiat Isot ; 124: 38-43, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28324824

RESUMO

Analysis of phosphorescence curves is an alternative procedure to glow curve analysis in order to find the parameters characterizing trap and recombination centers of thermoluminescence materials. In this article a new algorithm to analyze phosphorescence curves is reported, which is derived from the set of coupled differential equation describing the carrier traffic without resorting to approximations. The new algorithm has been employed to analyze the phosphorescence curves of the K2YF5:Pr compound.

10.
Clin Microbiol Infect ; 20(10): 1027-32, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24698304

RESUMO

After inheritance of chromosomally integrated HHV-6 (ciHHV-6), viral DNA is found in every nucleated cell. The prevalence of ciHHV-6 is estimated to be 0.2-5% of humans. There are conflicting data on the potential for replication, possibly leading to clinical implications. We analysed peripheral blood mononuclear cells (PBMCs) from individuals with ciHHV-6 proven by fluorescence in situ hybridization (FISH) for HHV-6-specific mRNA (U94, U42, U22) and antigens by means of reverse transcription PCR and an indirect immunoperoxidase staining. U94 transcripts indicative of latent infection were detected in six (54.5%) out of 11 individuals at least once. Transcripts indicative of lytic infection (i.e. U42 and U22) were detected in four (36.4%) out of 11 individuals at least once. HHV-6 antigen was detected in seven (70%) out of 10 individuals at least once. The presence of viral mRNA and proteins supports virus gene expression from ciHHV-6, which may lead to virus replication. Considering the properties of active HHV-6 infection together with obvious replicative activity in individuals with ciHHV-6, pathophysiological effects leading to clinical consequences of chromosomally integrated viral DNA might be considered.


Assuntos
Antígenos Virais/genética , Cromossomos Humanos/virologia , Herpesvirus Humano 6/imunologia , Leucócitos Mononucleares/virologia , Técnicas de Diagnóstico Molecular/métodos , RNA Mensageiro/genética , Infecções por Roseolovirus/diagnóstico , Adolescente , Adulto , Idoso , Antígenos Virais/metabolismo , Criança , Feminino , Herpesvirus Humano 6/genética , Humanos , Masculino , Pessoa de Meia-Idade , RNA Viral/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Infecções por Roseolovirus/sangue , Infecções por Roseolovirus/virologia , Sensibilidade e Especificidade , Integração Viral , Adulto Jovem
11.
Appl Radiat Isot ; 78: 33-7, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23665765

RESUMO

The glow curve of Al2O3:C compounds has been analyzed by employing a model consisting of two active traps, thermally disconnected traps and one recombination centre. The analysis takes into account interaction among traps and the thermal quenching of the thermoluminescent emission.


Assuntos
Óxido de Alumínio/química , Óxido de Alumínio/efeitos da radiação , Modelos Químicos , Dosimetria Termoluminescente/instrumentação , Dosimetria Termoluminescente/métodos , Simulação por Computador , Relação Dose-Resposta à Radiação , Elétrons , Desenho de Equipamento , Análise de Falha de Equipamento , Teste de Materiais , Fótons , Doses de Radiação
12.
Appl Radiat Isot ; 71 Suppl: 12-4, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22300945

RESUMO

Fiberoptic dosimetry (FOD) technique has become an attractive method for real-time dosimetry. Al(2)O(3):Cis one of the most used radioluminescence materials for FOD due to its high efficiency but it presents the drawback of emitting in the spectral region, where spurious luminescence is also important. Optical filtering is the simplest technique to remove spurious luminescence, but is useful when red-emitting scintillators are employed. In this work, the feasibility of using red-emitting Eu-doped phosphors as FOD scintillators has been investigated.


Assuntos
Óxido de Alumínio/química , Európio/química , Tecnologia de Fibra Óptica , Luminescência , Radiometria/métodos , Radiometria/instrumentação
13.
Eur J Clin Microbiol Infect Dis ; 31(7): 1523-9, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22113306

RESUMO

The impact of polymicrobial bacterial infection on chronic wounds has been studied extensively, but standard bacteriological analysis is not always sensitive enough. Molecular approaches represent a promising alternative to the standard bacteriological analysis. This work aimed to assess the usefulness of a panbacterial quantitative real-time PCR reaction to quantitate the total bacterial load in chronic wounds treated with Cutimed™ Sorbact™, a novel therapeutic approach based on hydrophobic binding of bacteria to a membrane. The results obtained by panbacterial real-time PCR on conserved sequences of the bacterial 16S gene show that the bacterial burden significantly decreased in 10 out of 15 healing chronic wounds, and did not change in 5 out of 5 non-healing chronic wounds. On the contrary, classical culture for S. aureus and P. aeruginosa, and real-time PCR for Bacteroides and Fusobacterium did not show any correlation with the clinical outcome. Our study also shows that quantification of chronic wounds by panbacterial real-time PCR is to be performed on biopsies and not on swabs. These results show that panbacterial real-time PCR is a promising and quick method of determining the total bacterial load in chronic wounds, and suggest that it might be an important biomarker for the prognosis of chronic wounds under treatment.


Assuntos
Bactérias/classificação , Bactérias/isolamento & purificação , Técnicas Bacteriológicas/métodos , Coinfecção/microbiologia , Reação em Cadeia da Polimerase em Tempo Real/métodos , Infecção dos Ferimentos/microbiologia , Bactérias/genética , Coinfecção/terapia , Método Duplo-Cego , Humanos , Projetos Piloto , RNA Ribossômico 16S/genética , Resultado do Tratamento , Infecção dos Ferimentos/terapia
14.
Radiat Prot Dosimetry ; 119(1-4): 148-52, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16766571

RESUMO

The parameters characterising the trap centres involved in the thermoluminescence of KMgF3:LaF3 compounds have been found by deconvolving the glow curve with the General One Trap model (GOT). For the fitting procedure the Levenberg-Marquardt method has been employed. Tm-T(stop) measurements along with initial rise measurements were performed in order to estimate the number of peaks the glow curve is made up of, and the corresponding activation energies. Instead of the Runge-Kutta method, a novel algorithm has been employed to integrate the differential equation of the GOT model, which reduces the computational time nearly 30 times with respect to the former when the glow curve is recorded with a lineal heating rate profile. The strong computational time reduction makes feasible a large number of runs with different guess values. An interesting result is that the concentration of disconnected deep traps is much less than the concentration of trap centres.


Assuntos
Fluoretos/química , Fluoretos/efeitos da radiação , Lantânio/química , Lantânio/efeitos da radiação , Compostos de Magnésio/química , Compostos de Magnésio/efeitos da radiação , Modelos Químicos , Dosimetria Termoluminescente/instrumentação , Dosimetria Termoluminescente/métodos , Simulação por Computador , Relação Dose-Resposta à Radiação , Desenho de Equipamento , Análise de Falha de Equipamento , Cinética , Teste de Materiais , Fósforo/química , Fósforo/efeitos da radiação , Potássio/química , Potássio/efeitos da radiação , Doses de Radiação , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
15.
Comp Immunol Microbiol Infect Dis ; 28(2): 155-66, 2005 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-15582691

RESUMO

Although DNA vaccines have several advantages over conventional vaccines, antibody production and protection are often not adequate, particularly in single plasmid vaccine formulations. Here we assessed the potential for a combined vaccine based on plasmids encoding the membrane-anchored or secreted forms of bovine herpesvirus type 1 (BHV-1) glycoprotein B and D (gB and gD) to induce neutralizing and cell mediated immune responses in mice. Animals were injected by intramuscular, subcutaneous and intranasal routes. Mice immunized with the combined vaccine containing the secreted forms of BHV-1 glycoproteins developed higher titers of anti-BHV-1 neutralizing antibodies, compared to wild type gB/gD combined plasmids and to single plasmid injected groups. Cellular immunity was also developed in mice immunized with combined vaccines, whereas low or no response were observed in single plasmid injected animals. The data suggest the potential use of this combined vaccine in in vivo trials of calves, in order to evaluate its protective efficacy.


Assuntos
Doenças dos Bovinos/imunologia , Doenças dos Bovinos/virologia , Infecções por Herpesviridae/veterinária , Herpesvirus Bovino 1/imunologia , Vacinas contra Herpesvirus/imunologia , Proteínas do Envelope Viral/imunologia , Proteínas Virais/imunologia , Administração Intranasal , Animais , Anticorpos Antivirais/sangue , Bovinos , Doenças dos Bovinos/prevenção & controle , DNA Viral/química , DNA Viral/genética , Ensaio de Imunoadsorção Enzimática , Feminino , Infecções por Herpesviridae/imunologia , Infecções por Herpesviridae/prevenção & controle , Infecções por Herpesviridae/virologia , Herpesvirus Bovino 1/genética , Vacinas contra Herpesvirus/administração & dosagem , Vacinas contra Herpesvirus/genética , Imunização , Camundongos , Camundongos Endogâmicos BALB C , Testes de Neutralização , Plasmídeos , Reação em Cadeia da Polimerase , Vacinas Combinadas/administração & dosagem , Vacinas Combinadas/genética , Vacinas Combinadas/imunologia , Vacinas de DNA/administração & dosagem , Vacinas de DNA/genética , Vacinas de DNA/imunologia , Proteínas do Envelope Viral/genética , Proteínas Virais/genética
16.
Mult Scler ; 10(4): 348-54, 2004 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-15327028

RESUMO

The presence and the replicative state of human herpesvirus 6 (HHV-6) were evaluated in clinical samples from multiple sclerosis (MS) patients at the first time of MS diagnosis. HHV-6 variant B was present in peripheral blood mononuclear cells of 5/32 (15%) patients, but persisted with a latent infection. Viral sequences were present also in cerebrospinal fluid (CSF), both free in the liquid (7/32, 22%) and latent in the cellular fraction (3/32, 9%), as shown by analysis of viral transcription. In these cases, variant A was detected. HHV-6 DNA sequences present in the CSF were associated to mature viral particles. In fact, in vitro infectious assays of CSF showed the presence of replication-competent virions. These results show that about 20% of MS patients have active foci of HHV-6 variant A infection in the early stages of the disease and suggest that viral replication takes place within the central nervous system.


Assuntos
Doenças do Sistema Nervoso Central/complicações , Herpesvirus Humano 6 , Esclerose Múltipla/complicações , Infecções por Roseolovirus/complicações , Doenças do Sistema Nervoso Central/sangue , Doenças do Sistema Nervoso Central/líquido cefalorraquidiano , Líquido Cefalorraquidiano/virologia , DNA Viral/líquido cefalorraquidiano , Ensaio de Imunoadsorção Enzimática , Herpesvirus Humano 6/genética , Herpesvirus Humano 6/fisiologia , Humanos , Esclerose Múltipla/sangue , Esclerose Múltipla/líquido cefalorraquidiano , Reação em Cadeia da Polimerase , Prevalência , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Infecções por Roseolovirus/epidemiologia , Vírion/fisiologia , Latência Viral , Replicação Viral
17.
Biochemistry ; 40(31): 9207-14, 2001 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-11478888

RESUMO

Third-generation cephalosporins are widely used beta-lactam antibiotics that resist hydrolysis by beta-lactamases. Recently, mutant beta-lactamases that rapidly inactivate these drugs have emerged. To investigate why third-generation cephalosporins are relatively stable to wild-type class C beta-lactamases and how mutant enzymes might overcome this, the structures of the class C beta-lactamase AmpC in complex with the third-generation cephalosporin ceftazidime and with a transition-state analogue of ceftazidime were determined by X-ray crystallography to 2.0 and 2.3 A resolution, respectively. Comparison of the acyl-enzyme structures of ceftazidime and loracarbef, a beta-lactam substrate, reveals that the conformation of ceftazidime in the active site differs from that of substrates. Comparison of the structures of the acyl-enzyme intermediate and the transition-state analogue suggests that ceftazidime blocks formation of the tetrahedral transition state, explaining why it is an inhibitor of AmpC. Ceftazidime cannot adopt a conformation competent for catalysis due to steric clashes that would occur with conserved residues Val211 and Tyr221. The X-ray crystal structure of the mutant beta-lactamase GC1, which has improved activity against third-generation cephalosporins, suggests that a tandem tripeptide insertion in the Omega loop, which contains Val211, has caused a shift of this residue and also of Tyr221 that would allow ceftazidime and other third-generation cephalosporins to adopt a more catalytically competent conformation. These structural differences may explain the extended spectrum activity of GC1 against this class of cephalosporins. In addition, the complexed structure of the transition-state analogue inhibitor (K(i) 20 nM) with AmpC reveals potential opportunities for further inhibitor design.


Assuntos
Proteínas de Bactérias , Ceftazidima/análogos & derivados , Ceftazidima/química , Inibidores Enzimáticos/química , Inibidores de beta-Lactamases , beta-Lactamases/química , Ácidos Borônicos/química , Cefalosporinas/química , Cristalografia por Raios X , Resistência Microbiana a Medicamentos/genética , Inibidores Enzimáticos/síntese química , Escherichia coli/enzimologia , Substâncias Macromoleculares , Mutagênese Sítio-Dirigida , beta-Lactamases/genética
18.
Chem Biol ; 8(6): 593-611, 2001 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-11410378

RESUMO

BACKGROUND: Group I beta-lactamases are a major cause of antibiotic resistance to beta-lactams such as penicillins and cephalosporins. These enzymes are only modestly affected by classic beta-lactam-based inhibitors, such as clavulanic acid. Conversely, small arylboronic acids inhibit these enzymes at sub-micromolar concentrations. Structural studies suggest these inhibitors bind to a well-defined cleft in the group I beta-lactamase AmpC; this cleft binds the ubiquitous R1 side chain of beta-lactams. Intriguingly, much of this cleft is left unoccupied by the small arylboronic acids. RESULTS: To investigate if larger boronic acids might take advantage of this cleft, structure-guided in-parallel synthesis was used to explore new inhibitors of AmpC. Twenty-eight derivatives of the lead compound, 3-aminophenylboronic acid, led to an inhibitor with 80-fold better binding (2; K(i) 83 nM). Molecular docking suggested orientations for this compound in the R1 cleft. Based on the docking results, 12 derivatives of 2 were synthesized, leading to inhibitors with K(i) values of 60 nM and with improved solubility. Several of these inhibitors reversed the resistance of nosocomial Gram-positive bacteria, though they showed little activity against Gram-negative bacteria. The X-ray crystal structure of compound 2 in complex with AmpC was subsequently determined to 2.1 A resolution. The placement of the proximal two-thirds of the inhibitor in the experimental structure corresponds with the docked structure, but a bond rotation leads to a distinctly different placement of the distal part of the inhibitor. In the experimental structure, the inhibitor interacts with conserved residues in the R1 cleft whose role in recognition has not been previously explored. CONCLUSIONS: Combining structure-based design with in-parallel synthesis allowed for the rapid exploration of inhibitor functionality in the R1 cleft of AmpC. The resulting inhibitors differ considerably from beta-lactams but nevertheless inhibit the enzyme well. The crystal structure of 2 (K(i) 83 nM) in complex with AmpC may guide exploration of a highly conserved, largely unexplored cleft, providing a template for further design against AmpC beta-lactamase.


Assuntos
Proteínas de Bactérias , Inibidores Enzimáticos/química , Inibidores de beta-Lactamases , Técnicas de Química Combinatória , Cristalografia por Raios X , Desenho de Fármacos , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/farmacologia , Estrutura Molecular , beta-Lactamases/química
19.
Chem Biol ; 8(1): 17-31, 2001 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11182316

RESUMO

BACKGROUND: Penicillins and cephalosporins are among the most widely used and successful antibiotics. The emergence of resistance to these beta-lactams, most often through bacterial expression of beta-lactamases, threatens public health. To understand how beta-lactamases recognize their substrates, it would be helpful to know their binding energies. Unfortunately, these have been difficult to measure because beta-lactams form covalent adducts with beta-lactamases. This has complicated functional analyses and inhibitor design. RESULTS: To investigate the contribution to interaction energy of the key amide (R1) side chain of beta-lactam antibiotics, eight acylglycineboronic acids that bear the side chains of characteristic penicillins and cephalosporins, as well as four other analogs, were synthesized. These transition-state analogs form reversible adducts with serine beta-lactamases. Therefore, binding energies can be calculated directly from K(i) values. The K(i) values measured span four orders of magnitude against the Group I beta-lactamase AmpC and three orders of magnitude against the Group II beta-lactamase TEM-1. The acylglycineboronic acids have K(i) values as low as 20 nM against AmpC and as low as 390 nM against TEM-1. The inhibitors showed little activity against serine proteases, such as chymotrypsin. R1 side chains characteristic of beta-lactam inhibitors did not have better affinity for AmpC than did side chains characteristic of beta-lactam substrates. Two of the inhibitors reversed the resistance of pathogenic bacteria to beta-lactams in cell culture. Structures of two inhibitors in their complexes with AmpC were determined by X-ray crystallography to 1.90 A and 1.75 A resolution; these structures suggest interactions that are important to the affinity of the inhibitors. CONCLUSIONS: Acylglycineboronic acids allow us to begin to dissect interaction energies between beta-lactam side chains and beta-lactamases. Surprisingly, there is little correlation between the affinity contributed by R1 side chains and their occurrence in beta-lactam inhibitors or beta-lactam substrates of serine beta-lactamases. Nevertheless, presented in acylglycineboronic acids, these side chains can lead to inhibitors with high affinities and specificities. The structures of their complexes with AmpC give a molecular context to their affinities and may guide the design of anti-resistance compounds in this series.


Assuntos
Antibacterianos/química , Antibacterianos/metabolismo , beta-Lactamases/metabolismo , Antibacterianos/farmacologia , Sítios de Ligação , Cristalografia por Raios X , Enterobacter cloacae/efeitos dos fármacos , Humanos , Técnicas In Vitro , Cinética , Modelos Moleculares , Eletricidade Estática , Termodinâmica , Resistência beta-Lactâmica , Inibidores de beta-Lactamases , beta-Lactamas
20.
Intervirology ; 44(1): 1-7, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11223713

RESUMO

Intramuscularly (i.m.) delivered plasmid DNA encoding a secreted form of glycoprotein B of herpes simplex virus type 1 (HSV-1 gB1s) was evaluated for the ability to elicit a protective immune response in Balb/c mice. Animals received three i.m. injections of a gB1s expression plasmid (pRP-RSV-gB1s) or of a wild-type transmembrane gB1 coding plasmid (pRP-RSV-gB1), while control mice were injected with the vector alone (pRP-RSV). A specific antibody response was observed in almost all immunized animals, and in most cases antibodies were also detected after 1 month in the absence of further vaccine boosts. Serum antibodies mostly displayed neutralizing activity against HSV-1. Glycoprotein B1s DNA immunization was also effective in protecting animals against the primary infection induced by a subsequent HSV-1 challenge and limited HSV-1 infection of sensitive ganglia.


Assuntos
DNA Viral/imunologia , Herpes Simples/virologia , Simplexvirus/imunologia , Vacinas de DNA/administração & dosagem , Proteínas do Envelope Viral/imunologia , Animais , Anticorpos Antivirais/sangue , DNA Viral/análise , Feminino , Gânglios Espinais/virologia , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Testes de Neutralização , Plasmídeos/imunologia , Reação em Cadeia da Polimerase , Vacinação , Proteínas do Envelope Viral/genética , Latência Viral
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