35 results on '"Pimenta AL"'
Search Results
2. ESTUDO COMPARATIVO ENTRE DIFERENTES TIPOS DE REVESTIMENTO INTERNO DE ANASTOMOSES ESOFÁGICAS EM CÃES
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Prado Filho Orlando Ribeiro, Nigro Amaury José Teixeira, Bandeira César Orlando Peralta, Juliano Yara, Novo Neil Ferreira, Lima Priscila Valério, and Pimenta Alex Moisés
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Anastomose cirúrgica ,Borracha ,Esôfago ,Cães ,Surgery ,RD1-811 - Abstract
O objetivo deste trabalho foi comparar, de modo prospectivo e casualizado, duas técnicas de sutura: uma com revestimento interno com dreno de PENROSE e outra utilizando a invaginação submucosa-mucosa nas anastomoses esôfago-esofágicas cervicais. Foram utilizados trinta e dois cães machos com pesos entre 8 e 10 Kg, distribuídos em dois grupos de dezesseis animais. Cada grupo foi dividido em dois subgrupos baseado nos períodos observados até o 7o e 14o dias de pós-operatórios. Em cada grupo, as anastomoses foram avaliadas em seus aspectos clínicos, macroscópicos e microscópicos. Nenhuma fístula ou óbito foi observado no pós-operatório. Todos os animais do grupo com revestimento interno com dreno de PENROSE apresentaram disfagia por tempo mínimo de sete dias, enquanto apenas quatro animais do grupo sutura com invaginação apresentaram disfagia transitória com duração máxima de dois dias. À microscopia óptica, foi observada deficiência na regeneração das túnicas submucosa e mucosa nas anastomoses com prótese. Os resultados observados permitem concluir que a anastomose esôfago-esofágica cervical com revestimento interno com dreno de PENROSE apresentou piores resultados do que a por invaginação.
- Published
- 1999
3. Recent Updates on Microbial Biofilms in Periodontitis: An Analysis of In Vitro Biofilm Models.
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Prado MM, Figueiredo N, Pimenta AL, Miranda TS, Feres M, Figueiredo LC, de Almeida J, and Bueno-Silva B
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- Biofilms, Humans, Plankton, Porphyromonas gingivalis genetics, Periodontitis, Treponema denticola genetics
- Abstract
The development of oral biofilm models has been extremely important to study the specific role of most microbial species at the early stages of periodontitis. The current knowledge on monospecies or multispecies biofilms originates mainly from the observation of in vitro dynamic or static biofilm model systems, which were engineered to mimic clinical oral conditions. In the last few decades, mounting evidence has confirmed that biofilms are the major form of bacterial lifestyle, and more importantly, that microorganisms dwelling in sessile mixed-species aggregates display completely different phenotypes and physiological characteristics than when living in planktonic pure cultures. Interspecies interactions within these communities, mediated by chemical communication systems, have been shown to affect biofilm physiology and increase antimicrobial resistance by up to 1000 fold. These aspects reinforce the importance of developing multispecies biofilm models to better understand and control biofilms. Literature reports demonstrate that while monospecies models are still most commonly used in caries research, authors have used different multispecies models to study periodontal diseases. Periodontitis is a polymicrobial biofilm-dependent disease mainly associated with Porphyromonas gingivalis, Tannerella forsythia, and Treponema denticola. Interestingly, these species hardly adhere to substrates commonly used for biofilm formation, which makes multispecies models essential for an accurate analysis of periodontitis-related biofilms. The multispecies models currently available are generally composed of 6-10 species, but a more recent 34-species model was developed to better examine the dynamics within oral biofilms. The complexity of such polymicrobial biofilm models mimics more consistently the oral microbiome and different aspects of the oral environment. Collectively, the evidence on multispecies biofilm models described herein may support future studies on the use of antimicrobials for biofilm control as well as provide research opportunities to expand the current knowledge on interspecies interactions. The present manuscript reviews the most recent updates on in vitro biofilm model systems for periodontitis., (© 2022. The Author(s), under exclusive license to Springer Nature Switzerland AG.)
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- 2022
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4. Early Biofilm Formation on Rough and Smooth Titanium Specimens: a Systematic Review of Clinical Studies.
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Scheeren Brum R, Apaza-Bedoya K, Labes LG, Volpato CÂM, Pimenta AL, and Benfatti CAM
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Objectives: There is a concern whether the enhancement on implant surface roughness is responsible for higher biofilm formation, which acts as an aetiological factor for peri-implant diseases. The aim of the present systematic review was to answer the following question: "Are rough surfaces more susceptible to early biofilm formation when compared to smoother surfaces on titanium specimens?"., Material and Methods: The research was performed on PubMed, Web of Science and Scopus, up to August 2021. Eligibility criteria included studies that analysed human biofilm formation on titanium specimens with distinct surface roughness (smooth vs minimally, moderate, or rough) over the experimental times of 1 or 3 days. Roughness average (Ra) and biofilm analysis parameters were extracted from selected articles. Risk of bias was evaluated using the Checklist for Quasi-Experimental Studies., Results: Of 5286 papers, 5 were included and analysed. Smooth titanium surfaces included machined and anodized titanium/Ti-6Al-4V; machined and acid etched TiZr. Minimally, moderately, or rough surfaces comprised titanium and titanium alloys (TiZr, Ti-6Al-4V), that received surface treatments (anodization, acid-etching, blasting, hydroxyapatite-coating). No statistically significant difference on biofilm formation on rough and smooth titanium surfaces was reported by 3 studies, while more contamination on rough titanium surfaces was stated by 2 investigations. An isolated smooth surface has also been associated to higher contamination. Moderate to high quality methodological assessment of studies were identified., Conclusions: It is not possible to assume that rough surfaces are more susceptible to early biofilm formation than smooth titanium surfaces. Additional studies are required to study this multifarious interaction., (Copyright © Brum RS, Apaza-Bedoya K, Labes LG, Volpato CAM, Pimenta AL, Benfatti CAM. Published in the JOURNAL OF ORAL & MAXILLOFACIAL RESEARCH (http://www.ejomr.org), 31 December 2021.)
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- 2021
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5. Strategies to Reduce Biofilm Formation in PEEK Materials Applied to Implant Dentistry-A Comprehensive Review.
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Brum RS, Labes LG, Volpato CÂM, Benfatti CAM, and Pimenta AL
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Polyether-ether-ketone (PEEK) has emerged in Implant Dentistry with a series of short-time applications and as a promising material to substitute definitive dental implants. Several strategies have been investigated to diminish biofilm formation on the PEEK surface aiming to decrease the possibility of related infections. Therefore, a comprehensive review was carried out in order to compare PEEK with materials widely used nowadays in Implant Dentistry, such as titanium and zirconia, placing emphasis on studies investigating its ability to grant or prevent biofilm formation. Most studies failed to reveal significant antimicrobial activity in pure PEEK, while several studies described new strategies to reduce biofilm formation and bacterial colonization on this material. Those include the PEEK sulfonation process, incorporation of therapeutic and bioactive agents in PEEK matrix or on PEEK surface, PEEK coatings and incorporation of reinforcement agents, in order to produce nanocomposites or blends. The two most analyzed surface properties were contact angle and roughness, while the most studied bacteria were Escherichia coli and Staphylococcus aureus . Despite PEEK's susceptibility to biofilm formation, a great number of strategies discussed in this study were able to improve its antibiofilm and antimicrobial properties.
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- 2020
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6. Prevalence of low back pain in young Brazilians and associated factors: Sex, physical activity, sedentary behavior, sleep and body mass index.
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Schwertner DS, Oliveira RANS, Koerich MHAL, Motta AF, Pimenta AL, and Gioda FR
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- Adolescent, Brazil epidemiology, Cross-Sectional Studies, Female, Humans, Low Back Pain etiology, Male, Prevalence, Risk Factors, Sex Factors, Students statistics & numerical data, Surveys and Questionnaires, Waist Circumference, Body Mass Index, Exercise physiology, Low Back Pain epidemiology, Sedentary Behavior, Sleep physiology
- Abstract
Background: Low back pain (LBP) has become increasingly common, but the prevalence of this complaint and associated factors in young people remains controversial., Objective: This study aimed to identify the prevalence of LBP and to explore the existence of associated factors (sex, physical activity, sedentary lifestyle, sleep, body mass index and waist circumference)., Methods: This study considered all complaints of the lumbar region (acute or chronic) as LBP, which can irradiate to the backside and legs, lasting a minimum of 24 hours. Youngsters aged 15 to 18 years from a school in the south of Brazil were evaluated. Descriptive statistics was used, in particular Chi-square, Mann-Whitney U tests and binary logistic regression. A significance level of p< 0.05 was adopted., Results: A total of 330 youngsters answered a questionnaire and had their anthropometric measurements measured (response rate 84%). The prevalence of LBP in the present was 30%, quarterly 63% and throughout life 77%. There was a significant association between LBP and sex: girls have an increased risk of LBP in the last three-month period (PR = 1.3, 95% CI 1.06-1.56) and throughout life (PR = 1.2, 95% CI 1.04-1.43). The practice of physical activities was also associated with LBP, but as a protection factor in the present and in the last three-month period (PR = 0.7, 95% CI 0.47-0.90). Physical education at school has demonstrated a protective factor regarding LBP throughout life (PR = 0.9, 95% CI 0.77-0.97). Most of the students did not comply with recommendations related to sleep and time spent doing activities in front of a screen, and no association of these factors with LBP was detected. This exposure (physical activity, sleep time, sedentarism) did not present significant association with LBP when adjusted by the confusion factors (sex, age, BMI)., Conclusions: Youngsters reported a high prevalence of LBP. Girls were at greater risk of LBP than boys. It is recommended that prevention strategies focus on the practices of physical activities and scholar physical education. No association of LBP with sedentary lifestyle (TV and computer use time, sleep time), anthropometric measures and sleeping duration was observed.
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- 2020
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7. Effects of three γ-alkylidene-γ-lactams on the formation of multispecies biofilms.
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de Almeida J, Pimenta AL, Pereira UA, Barbosa LCA, Hoogenkamp MA, van der Waal SV, Crielaard W, and Felippe WT
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- Biofilms growth & development, Candida glabrata drug effects, Candida glabrata growth & development, Cells, Cultured, Dimethyl Sulfoxide pharmacology, Enterococcus faecalis drug effects, Enterococcus faecalis growth & development, Fibroblasts drug effects, Humans, Lactams chemistry, Microbial Sensitivity Tests, Streptococcus mutans drug effects, Streptococcus mutans growth & development, Biofilms drug effects, Lactams pharmacology
- Abstract
This study evaluated the inhibitory effects of lactams on Streptococcus mutans, Enterococcus faecalis, and Candida glabrata multispecies biofilm formation. γ-Alkylidene-γ-lactams 1, 2, and 3 [solubilized in 3.5% dimethyl sulfoxide (DMSO)] were tested. Glass coverslips were conditioned with either the lactams or 3.5% DMSO (control) for 1 h, inoculated with microbial cultures, and incubated for 48 h. To assess the effect of the lactams on biofilm formation, the following parameters were determined: the biofilm biomass (by both crystal violet staining and protein determination); the amount of insoluble polysaccharides of the extracellular matrix; and the number of viable and total cells [by both colony-forming unit counting and quantitative real-time PCR (qPCR)]. Data were analysed using one-way anova and post-hoc Tukey tests. Lactams 1, 2, and 3 promoted a statistically significant reduction in the amount of biofilm biomass, but only lactam 3 resulted in a statistically significant reduction in the number of attached viable E. faecalis. Both total protein content and the amount of extracellular polysaccharides decreased significantly. The effects of γ-alkylidene-γ-lactams 1, 2, and 3 on the inhibition of multispecies biofilm formation were evident by their ability to reduce the amount of protein and extracellular polysaccharides., (© 2018 Eur J Oral Sci.)
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- 2018
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8. Effect of γ-lactones and γ-lactams compounds on Streptococcus mutans biofilms.
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Sordi MB, Moreira TA, Montero JFD, Barbosa LC, Benfatti CAM, Magini RS, Pimenta AL, and Souza JCM
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- Analysis of Variance, Anti-Bacterial Agents chemical synthesis, Biofilms growth & development, Colony Count, Microbial, Dose-Response Relationship, Drug, Gentian Violet, Lactones chemical synthesis, Microbial Sensitivity Tests, Microbial Viability drug effects, Microscopy, Electron, Scanning, Plankton drug effects, Plankton growth & development, Reproducibility of Results, Streptococcus mutans growth & development, beta-Lactam Resistance drug effects, beta-Lactams chemical synthesis, Anti-Bacterial Agents pharmacology, Biofilms drug effects, Lactones pharmacology, Streptococcus mutans drug effects, beta-Lactams pharmacology
- Abstract
Considering oral diseases, antibiofilm compounds can decrease the accumulation of pathogenic species such as Streptococcus mutans at micro-areas of teeth, dental restorations or implant-supported prostheses., Objective: To assess the effect of thirteen different novel lactam-based compounds on the inhibition of S. mutans biofilm formation., Material and Methods: We synthesized compounds based on γ-lactones analogues from rubrolides by a mucochloric acid process and converted them into their corresponding γ-hydroxy-γ-lactams by a reaction with isobutylamine and propylamine. Compounds concentrations ranging from 0.17 up to 87.5 μg mL-1 were tested against S. mutans. We diluted the exponential cultures in TSB and incubated them (37°C) in the presence of different γ-lactones or γ-lactams dilutions. Afterwards, we measured the planktonic growth by optical density at 630 nm and therefore assessed the biofilm density by the crystal violet staining method., Results: Twelve compounds were active against biofilm formation, showing no effect on bacterial viability. Only one compound was inactive against both planktonic and biofilm growth. The highest biofilm inhibition (inhibition rate above 60%) was obtained for two compounds while three other compounds revealed an inhibition rate above 40%., Conclusions: Twelve of the thirteen compounds revealed effective inhibition of S. mutans biofilm formation, with eight of them showing a specific antibiofilm effect.
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- 2018
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9. Biofilm behavior on sulfonated poly(ether-ether-ketone) (sPEEK).
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Montero JF, Tajiri HA, Barra GM, Fredel MC, Benfatti CA, Magini RS, Pimenta AL, and Souza JC
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- Benzophenones, Enterococcus faecalis drug effects, Magnetic Resonance Spectroscopy, Microscopy, Electron, Scanning, Plankton drug effects, Plankton growth & development, Polymers, Spectroscopy, Fourier Transform Infrared, Streptococcus mutans drug effects, Thermogravimetry, Biofilms drug effects, Ketones pharmacology, Polyethylene Glycols pharmacology, Sulfonic Acids pharmacology
- Abstract
Poly(ether-ether-ketone) (PEEK) has also shown to be very attractive for incorporating therapeutic compounds thanks to a sulfonation process which modifies the material structure resulting in a sulfonated-PEEK (sPEEK). Concerning biomedical applications, the objective of this work was to evaluate the influence of different sulfonation degree of sPEEK on the biofilm growth. PEEK samples were functionalized by using sulphuric acid (98%) and then dissolved into dimethyl-sulfoxide. A dip coating technique was used to synthesize sPEEK thin films. The sulfonation degree of the materials was analyzed by FT-IR, H NMR, TG and IEC. The surfaces were characterized by scanning electron microscopy, profilometry and contact angle analyses. Subsequently, the biofilm formation on sulfonated-PEEK based on Streptococcus mutans and Enterococcus faecalis was measured by spectrophotometry, colony forming units (CFUmL
-1 ) and SEM. Results obtained from thermal and chemical analyses showed an intensification in sulfonation degree for sPEEK at 2 and 2.5h. The E. faecalis or S. mutans biofilm growth revealed statistically significant differences (p<0.05) between 2 and 3h sulfonation groups. A significant decrease (p<0.05) in CFUmL-1 was recorded for S. mutans or E. faecalis biofilm grown on 2.5 or 3h sPEEK. Regarding the thermal-chemical and microbiologic analyses, the sulfonation degree of sPEEK ranging from 2 up to 3h was successful capable to decrease the biofilm growth. That revealed an alternative strategy to embed anti-biofilm and therapeutic compounds into PEEK avoiding infections in biomedical applications., (Copyright © 2016 Elsevier B.V. All rights reserved.)- Published
- 2017
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10. Chemical, microscopic, and microbiological analysis of a functionalized poly-ether-ether-ketone-embedding antibiofilm compounds.
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Montero JF, Barbosa LC, Pereira UA, Barra GM, Fredel MC, Benfatti CA, Magini RS, Pimenta AL, and Souza JC
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- Anti-Bacterial Agents chemistry, Benzophenones, Biocompatible Materials chemistry, Humans, Ketones chemistry, Lactams chemistry, Polyethylene Glycols chemistry, Polymers, Streptococcus mutans growth & development, Streptococcus mutans physiology, Surface Properties, Anti-Bacterial Agents pharmacology, Biocompatible Materials pharmacology, Biofilms drug effects, Ketones pharmacology, Lactams pharmacology, Polyethylene Glycols pharmacology, Streptococcus mutans drug effects
- Abstract
Poly-ether-ether-ketone (PEEK) is currently introduced as an alternative material for orthopedic implants due to its biocompatibility and low elastic modulus compared to titanium. Also, a sulphonation treatment can functionalize PEEK to embed therapeutical substances. The objective of this work was to functionalize a PEEK film to incorporate novel lactam-based antibiofilms compounds. PEEK samples were functionalized by sulphuric acid treatment and then dissolved in dimethylsulfoxide, where lactams were added to be incorporated into the polymer. A dip-coating technique was used to synthesize a thin film on a glass-based substrate. The degree of sulfonation (DS) and the incorporation of lactams into sulphonated PEEK (sPEEK) were analyzed by Fourier transform infrared spectroscopy, nuclear magnetic resonance, thermogravimetric analysis (TGA), and scanning electron microscopy. A DS of 65% was obtained and TGA curves confirmed the presence of SO
3 H and lactams in the sPEEK structure. The growth of Streptococcus mutans biofilm decreased on sPEEK surface containing lactams when compared to sPEEK free of lactams. That indicated the antibiofilm activity of those compounds was maintained after incorporation into sPEEK. Planktonic growth analysis showed no long distant effects of sPEEK containing lactams, indicating that no systemic effects should be expected upon clinical uses of medical devices produced with lactam-treated sPEEK. Results revealed that inclusion of lactams into sPEEK represents a good alternative for the production of biomaterials resistant to bacterial accumulation. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 3015-3020, 2016., (© 2016 Wiley Periodicals, Inc.)- Published
- 2016
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11. IL-6 serum levels are elevated in Parkinson's disease patients with fatigue compared to patients without fatigue.
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Pereira JR, Santos LVD, Santos RMS, Campos ALF, Pimenta AL, de Oliveira MS, Bacheti GG, Rocha NP, Teixeira AL, Christo PP, and Scalzo PL
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- Aged, Antiparkinson Agents therapeutic use, Biomarkers blood, Female, Humans, Logistic Models, Male, Mental Status Schedule, Middle Aged, Parkinson Disease drug therapy, ROC Curve, Severity of Illness Index, Treatment Outcome, Fatigue blood, Fatigue complications, Interleukin-6 blood, Parkinson Disease blood, Parkinson Disease complications
- Abstract
To investigate the influence of interleukin-6 (IL-6) and soluble tumor necrosis factor receptors (sTNFR) in fatigued Parkinson's disease (PD) patients. Forty-four PD patients were evaluated, and fatigue was assessed with the Parkinson Fatigue Scale. Logistic regression analysis was used to evaluate the contribution of disease severity scores and cytokine levels on fatigue scores. A receiver operating characteristic (ROC) curve was used to evaluate the diagnostic values of IL-6 in fatigue. Fatigued PD patients had worse cognitive function and depressive symptoms. These patients had worse PD signs and symptoms, displayed more advanced stages of PD, and had greater functional dependence. There was a significant difference in IL-6 serum levels (p=0.026), but there was no difference in sTNFR levels. Total scores on the Unified Parkinson Disease Rating Scale (β=1.108; p=0.004) and IL-6 levels (β=12.843; p=0.020) were found to be significant predictors of fatigue scores. A ROC curve revealed that IL-6 concentrations of 1.18pg/ml represented the best cut-off value for detecting fatigue (sensitivity of 0.941 and specificity of 0.704). Fatigued PD patients have poor clinical outcomes and elevated IL-6 serum levels when compared with non-fatigued patients. These results suggest that IL-6 may play a role in the pathophysiology of fatigue in PD., (Copyright © 2016. Published by Elsevier B.V.)
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- 2016
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12. Lactam inhibiting Streptococcus mutans growth on titanium.
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Xavier JG, Geremias TC, Montero JFD, Vahey BR, Benfatti CAM, Souza JCM, Magini RS, and Pimenta AL
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- Alloys, Microscopy, Electrochemical, Scanning, Streptococcus mutans ultrastructure, Biofilms drug effects, Biofilms growth & development, Lactams chemistry, Lactams pharmacology, Streptococcus mutans physiology, Titanium chemistry
- Abstract
The aim of this work was to analyze the activity of novel synthetic lactams on preventing biofilm formation on titanium surfaces. Titanium (Ti6Al4V) samples were exposed to Streptococcus mutans cultures in the presence or absence of a synthetic lactam. After 48h incubation, planktonic growth was determined by spectrophotometry. Biofilm was evaluated by crystal violet staining and colony forming units (CFU·ml(-)(1)), followed by scanning electron microscopy (SEM). Results showed that the average of adhered viable cells was approximately 1.5×10(2)CFU/ml in the presence of lactam and 4×10(2)CFU/ml in its absence. This novel compound was considerable active in reducing biofilm formation over titanium surfaces, indicating its potential for the development of antimicrobial drugs targeting the inhibition of the initial stages of bacterial biofilms on dental implants abutments., (Copyright © 2016 Elsevier B.V. All rights reserved.)
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- 2016
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13. Simultaneous detection of human papillomavirus integration and c-MYC gene amplification in cervical lesions: an emerging marker for the risk to progression.
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Gimenes F, Souza RP, de Abreu AL, Pereira MW, Consolaro ME, and da Silva VR
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- Adult, Disease Progression, Female, Genotype, Human papillomavirus 16 genetics, Human papillomavirus 18 genetics, Humans, Middle Aged, Papillomavirus Infections genetics, Papillomavirus Infections virology, Polymerase Chain Reaction methods, Squamous Intraepithelial Lesions of the Cervix diagnosis, Squamous Intraepithelial Lesions of the Cervix virology, Uterine Cervical Dysplasia diagnosis, Uterine Cervical Dysplasia genetics, Uterine Cervical Dysplasia virology, Uterine Cervical Neoplasms diagnosis, Uterine Cervical Neoplasms virology, Gene Amplification, Genes, myc genetics, In Situ Hybridization, Fluorescence methods, Papillomaviridae genetics, Papillomavirus Infections diagnosis, Squamous Intraepithelial Lesions of the Cervix genetics, Uterine Cervical Neoplasms genetics
- Abstract
Purpose: The persistence of high-risk oncogenic human papillomavirus (HR-HPV) infection and its integration into the host genome are key steps in the induction of malignant alterations. c-MYC chromosome region is a frequent localization for HPV insertion that has been observed in chromosome band 8q24 by fluorescence in situ hybridization (FISH). We report the HPV viral integration and amplification patterns of the c-MYC gene in cytological smears with FISH as a potential biomarker for the progression of squamous intraepithelial lesions (SIL)., Methods: HPV detection and genotyping by polymerase chain reaction (PCR) and FISH analysis by "Vysis Cervical FISH Probe" kit (ABBOTT Molecular Inc.) were performed in 37 cervical samples including 8 NILM, 7 ASC-US, 7 LSIL, 3 ASC-H, 7 HSIL and 5 SCC., Results: The results show concordance between FISH and PCR techniques for HPV detection. The majority of the samples contained HR-HPV, the majority being -16 and -18 genotypes. HPV integration as determined by FISH was most frequent in high-risk lesions. The c-MYC gene amplification was found only in HPV-positive samples and was detected primarily in high-risk lesions and in cells with an integrated form of HPV., Conclusions: HPV integration and c-MYC gene amplification detected by FISH could be an important biomarker for use in clinical practice to determine SIL with a risk of progression.
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- 2016
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14. A laboratory assessment of bacterial leakage in MTA apical plugs exposed to phosphate-buffered saline.
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de Almeida J, Pimenta AL, and Felippe WT
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- Dental Leakage, Humans, Oxides, Phosphates, Root Canal Filling Materials, Aluminum Compounds chemistry, Calcium Compounds chemistry, Silicates chemistry
- Abstract
This study evaluated the influence of the exposure of mineral trioxide aggregate (MTA) - with and without calcium chloride (CaCl2) -to phosphate-buffered saline (PBS) on apical microleakage. Sixty root segments were divided into 4 experimental groups (n=15). Apical cavities were filled with MTA with or without CaCl2, and the root canals dressed with a moistened cotton pellet or PBS: 1) MTA/cotton pellet; 2) MTA/PBS; 3) MTA+ 10%CaCl2/cotton pellet; 4) MTA+10%CaCl2/PBS. After 2 months, E. faecalis penetration was analyzed along the apical plugs. Samples were observed weekly for 70 days, and leakage was detected by turbidity of the medium in contact with the root segment. Teeth in the control groups (n=2) were either made completely impermeable or kept without an apical plug. The Kaplan-Meier method was used to analyze survival and the Logrank test was used to compare the survival curves (p<0.05). All specimens in the positive control group showed evidence of leakage within 24h, while none in the negative control group showed leakage up to 70 days. There was no statistically significant difference among the experimental groups (p=0.102). The use of PBS as intracanal dressing may improve MTA sealing ability, but cannot prevent bacterial leakage. The addition of CaCl2 to the MTA did not improve MTA sealing ability.
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- 2015
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15. Human leukocyte antigen (HLA)-G and cervical cancer immunoediting: a candidate molecule for therapeutic intervention and prognostic biomarker?
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Gimenes F, Teixeira JJ, de Abreu AL, Souza RP, Pereira MW, da Silva VR, Bôer CG, Maria-Engler SS, Bonini MG, Borelli SD, and Consolaro ME
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- Female, HLA-G Antigens genetics, Humans, Polymorphism, Genetic, Prognosis, Uterine Cervical Neoplasms etiology, Uterine Cervical Neoplasms therapy, HLA-G Antigens physiology, Uterine Cervical Neoplasms immunology
- Abstract
While persistent infection with oncogenic types of human Papillomavirus (HPV) is required for cervical epithelial cell transformation and cervical carcinogenesis, HPV infection alone is not sufficient to induce tumorigenesis. Only a minor fraction of HPV infections produce high-grade lesions and cervical cancer, suggesting complex host-virus interactions. Based on its pronounced immunoinhibitory properties, human leukocyte antigen (HLA)-G has been proposed as a possible prognostic biomarker and therapeutic target relevant in a wide variety of cancers and viral infections, but to date remains underexplored in cervical cancer. Given the possible influence of HLA-G on the clinical course of HPV infection, cervical lesions and cancer progression, a better understanding of HLA-G involvement in cervical carcinogenesis might contribute to two aspects of fundamental importance: 1. Characterization of a novel diagnostic/prognostic biomarker to identify cervical cancer and to monitor disease stage, critical for patient screening; 2. Identification of HLA-G-driven immune mechanisms involved in lesion development and cancer progression, leading to the development of strategies for modulating HLA-G expression for treatment purposes. Thus, this systematic review explores the potential involvement of HLA-G protein expression and polymorphisms in cervical carcinogenesis., (Copyright © 2014 Elsevier B.V. All rights reserved.)
- Published
- 2014
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16. Inhibition of Enterococcus faecalis biofilm formation by highly active lactones and lactams analogues of rubrolides.
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Pereira UA, Barbosa LC, Maltha CR, Demuner AJ, Masood MA, and Pimenta AL
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- Anti-Bacterial Agents chemical synthesis, Dose-Response Relationship, Drug, Enterococcus faecalis growth & development, Furans chemistry, Lactams chemical synthesis, Lactams chemistry, Lactones chemical synthesis, Lactones chemistry, Microbial Sensitivity Tests, Molecular Structure, Structure-Activity Relationship, Anti-Bacterial Agents pharmacology, Biofilms drug effects, Enterococcus faecalis drug effects, Lactams pharmacology, Lactones pharmacology
- Abstract
Seven β-aryl substituted γ-alkylidene-γ-lactones analogues of rubrolides were synthesized from mucobromic acid and converted through a lactamization with isobutylamine into their corresponding γ-hydroxy-γ-lactams (76-85%). These lactams were converted into (Z)- and (E)-γ-alkylidene-γ-lactams (23-45%). All compounds were fully characterized by IR, NMR ((1)H and (13)C), COSY and HETCOR bidimensional experiments, and NOE difference spectroscopy experiments when necessary. Evaluation of these three different classes of compounds against Enterococcus faecalis biofilm formation showed that all classes are active and the highest biofilm inhibition activity was caused by lactam 13f (IC50 = 0.76 μg/mL). Moreover, in almost all cases at least one of the lactams is more active than its correspondent γ-alkylidene-γ-lactone. The use of rubrolides as a lead structure has proven successful for the identification of new compounds displaying novel antibacterial activities, namely biofilm inhibition, which have the potential for the development of antimicrobial drugs targeted to inhibition of the initial stages of bacterial infections, rather than bacterial viability. Such drugs are less prompt to induce bacterial resistance, being therefore a more cost-effective investment for pharmaceutical research., (Copyright © 2014 Elsevier Masson SAS. All rights reserved.)
- Published
- 2014
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17. γ-Alkylidene-γ-lactones and isobutylpyrrol-2(5H)-ones analogues to rubrolides as inhibitors of biofilm formation by gram-positive and gram-negative bacteria.
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Pereira UA, Barbosa LC, Maltha CR, Demuner AJ, Masood MA, and Pimenta AL
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- Anti-Bacterial Agents chemical synthesis, Anti-Bacterial Agents chemistry, Dose-Response Relationship, Drug, Furans chemical synthesis, Furans chemistry, Lactones chemical synthesis, Lactones chemistry, Microbial Sensitivity Tests, Molecular Structure, Pseudomonas aeruginosa drug effects, Small Molecule Libraries chemical synthesis, Small Molecule Libraries chemistry, Staphylococcus aureus drug effects, Staphylococcus epidermidis drug effects, Streptococcus mutans drug effects, Structure-Activity Relationship, Anti-Bacterial Agents pharmacology, Biofilms drug effects, Furans pharmacology, Lactones pharmacology, Small Molecule Libraries pharmacology
- Abstract
Several molecules have been discovered that interfere with formation of bacterial biofilms, opening a new strategy for the development of more efficient treatments in case of antibiotic resistant bacteria. Amongst the most active compounds are some natural brominated furanones from marine algae Delisea pulchra that have proven to be able to control pathogenic biofilms. We have recently reported that some rubrolide analogues are able to inhibit biofilm formation of Enterococcus faecalis. In the present Letter we describe results of the biological evaluation of a small library of 28 compounds including brominated furanones and the corresponding lactams against biofilm formation of Staphylococcus aureus, Pseudomonas aeruginosa, Staphylococcus epidermidis and Streptococcus mutans. Our results showed that in general these compounds were more active against biofilms of S. epidermidis and P. aeruginosa, with little or no inhibition of planktonic bacterial growth. In some cases they were able to prevent biofilm formation of P. aeruginosa at concentrations as low as 0.6 μg/mL (1.3 μM, compound 3d) and 0.7 μg/mL (1.3 μM, 3f). Results also indicate that, in general, lactams are more active against biofilms than their precursors, thus designating this class of molecules as good candidates for the development of a new generation of antimicrobial drugs targeted to biofilm inhibition., (Copyright © 2014 Elsevier Ltd. All rights reserved.)
- Published
- 2014
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18. Children with phenylketonuria treated early: basic audiological and electrophysiological evaluation.
- Author
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Mancini PC, Durrant JD, Starling AL, and Iório MC
- Subjects
- Acoustic Impedance Tests, Adolescent, Audiometry, Pure-Tone, Audiometry, Speech, Case-Control Studies, Child, Child, Preschool, Cross-Sectional Studies, Female, Humans, Male, Patient Compliance, Phenylketonurias physiopathology, Early Medical Intervention, Evoked Potentials, Auditory, Brain Stem physiology, Phenylketonurias diet therapy
- Abstract
Objectives: Individuals with phenylketonuria (PKU) can exhibit deficits in executive functions, intelligence, attention, visual-spatial processing abilities, and efficiency stemming presumably from deficient neurotransmitter synthesis, even when the disorder is diagnosed and treated early. Basic audiological and electrophysiological evaluations were used to examine the peripheral and central auditory pathways of children with early-treated PKU, who followed adequate versus inadequate diets. Results were compared with those of age-matched children without PKU., Design: The control group included 35 children aged 5 to 16 years, and the experimental group included 25 children with classic PKU, all of whom were diagnosed and treated early. The experimental group comprised children of two subgroups, divided according to their dietary control, as follows: 8 children aged 6 to 13 years with adequate diets (group A); 17 children ages 6 to 15 years demonstrating inadequate diets (group B). All participants underwent auditory evaluations, including otoscopy, pure-tone and speech audiometry, immittance testing (tympanometry and assessment of contralateral stapedial reflex thresholds), and evaluations of auditory brainstem and middle latency responses. The demographic variables and audiological examination results were analyzed for all groups. Results among groups and subgroups were compared using analysis of variance with repeated measures to test statistical significance across factors and measures at the p = 0.05 level., Results: Audiometric evaluation revealed results within normal limits for all groups, except for one child from the inadequate diet group, who showed a mild bilateral conductive hearing loss. Results of speech and immittance audiometry suggested the children in group B as having poorer average speech-discrimination scores and higher stapedial reflex thresholds at 4000 Hz. Auditory brainstem response results revealed longer average latencies for waves III and V and greater interaural differences for wave V in group B, although both groups A and B showed longer average latencies for the interpeak interval I-V, compared with the control group. Middle latency responses showed no significant differences in the latencies of the Na and Pa waves or the Na-Pa amplitude for the experimental group, but electrode or ear effects were present in 87.5% of group A and 58.8% of group B., Conclusions: Overall, differences observed tended to be small (by clinical diagnostic standards), yet suggest that children with PKU exhibit some effect of this disorder on the pontine auditory pathway, even when diagnosed/treated early and independent of the appropriateness of diet. It thus seems prudent to follow PKU children with auditory processing assessments to evaluate functional implications of these findings.
- Published
- 2013
- Full Text
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19. Relationships between phenylalanine levels, intelligence and socioeconomic status of patients with phenylketonuria.
- Author
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Castro IP, Borges JM, Chagas HA, Tibúrcio J, Starling AL, and Aguiar MJ
- Subjects
- Analysis of Variance, Child, Female, Humans, Intellectual Disability prevention & control, Logistic Models, Male, Wechsler Scales, Intelligence, Phenylalanine blood, Phenylketonurias blood, Phenylketonurias psychology, Social Class
- Abstract
Objectives: To assess intelligence and its relationship with blood phenylalanine concentrations and socioeconomic status in patients with phenylketonuria after 6 to 12 years of treatment., Methods: Sixty-three children were classified according to phenylalanine levels and socioeconomic status and assessed using the Wechsler Intelligence Scale for Children. The Statistical Package for the Social Sciences (SPSS) was used to analyze phenylalanine; ANOVA was used to analyze intelligence quotients (IQ) and phenylalanine levels; and ordinal logistic regression was used to analyze the likelihood of higher IQ., Results: The overall IQ scores of 90.5% of the children were within a range from borderline intellectual deficiency to very high intelligence; for verbal IQ this proportion was 96.8% and 92.1% had performance IQ scores within this band. The categories from low to upper-medium socioeconomic status contained 98.4% of patients' families. The likelihood of having medium to high IQ was 4.29 times greater for children with good phenylalanine control and 4.03 greater for those from higher socioeconomic strata., Conclusions: Treatment prevented mental retardation in 90.5% of the patients. Control of phenylalanine levels and higher socioeconomic status were associated with higher IQ scores.
- Published
- 2012
- Full Text
- View/download PDF
20. Duodenal perforation caused by Rhizomucor species in a cat.
- Author
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Cunha SC, Aguero C, Damico CB, Corgozinho KB, Souza HJ, Pimenta AL, and Marassi CD
- Subjects
- Animals, Cats, Duodenal Diseases microbiology, Fatal Outcome, Female, Intestinal Perforation microbiology, Mucormycosis complications, Opportunistic Infections veterinary, Cat Diseases microbiology, Duodenal Diseases veterinary, Intestinal Perforation veterinary, Mucormycosis veterinary, Rhizomucor isolation & purification
- Abstract
Unlabelled: CLINICAL SUMMARY: A 7-month-old female Persian cat presented with gastrointestinal (GI) necrosis and perforation caused by Rhizomucor species. Unfortunately, the cat died of bacterial peritonitis and sepsis before a definitive diagnosis, based on histopathology and fungal culture, was achieved., Practical Relevance: This appears to be the first reported case of GI disease caused by Rhizomucor species in a cat. Mucorales infections typically cause acute and rapidly progressive disease. As illustrated by this case, clinicians should be alert to the potentially fatal consequences of an opportunistic Rhizomucor species infection in their feline patients., (Copyright © 2011 ISFM and AAFP. Published by Elsevier Ltd. All rights reserved.)
- Published
- 2011
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21. [Assessment of the cervical cancer screening in the Family Health Strategy in Amparo, São Paulo State, Brazil].
- Author
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Vale DB, Morais SS, Pimenta AL, and Zeferino LC
- Subjects
- Adolescent, Adult, Age Distribution, Child, Child, Preschool, Early Detection of Cancer standards, Early Detection of Cancer statistics & numerical data, Female, Guideline Adherence, Humans, Infant, Infant, Newborn, Mass Screening statistics & numerical data, Middle Aged, Program Evaluation, Time Factors, Uterine Cervical Neoplasms prevention & control, Young Adult, Early Detection of Cancer methods, Family Health, Mass Screening standards, Papanicolaou Test, Uterine Cervical Neoplasms diagnosis, Vaginal Smears statistics & numerical data
- Abstract
Uterine cervical cancer mortality has not been declining. The territorial distribution and registration of families in Brazil's Family Health Strategy help identify women that have performed a Pap smear or that have not had one for more than three years. This study analyzed whether cervical cancer screening in Amparo, São Paulo State, Brazil, made progress in complying with the prevailing guidelines during the seven years of experience with the Strategy. The annual examination rate remained high, with a slight trend towards greater intervals between follow-up tests. Distribution of tests tended to increase in the 40-59-year age bracket and decrease in the over-60 age group, while annual coverage tended to decrease. The proportions of excess tests varied from 61.2% to 65.5%. Concluding, the upgrading of cervical cancer screening was slight, and did not change the opportunistic pattern of follow-up tests. Considering that community health agents can act to increase the coverage of these measures, it is essential to train them for this work.
- Published
- 2010
- Full Text
- View/download PDF
22. Positive correlation between in vivo and in vitro assays for the evaluation of Pseudomonas virulence.
- Author
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Pimenta AL, Di Martino P, and Blight MA
- Subjects
- Animals, Bacterial Adhesion drug effects, Bacterial Adhesion genetics, Bacterial Adhesion physiology, Bacterial Proteins genetics, Bacterial Proteins metabolism, Drosophila melanogaster drug effects, Drosophila melanogaster microbiology, Electrophoresis, Polyacrylamide Gel, Iron metabolism, Iron pharmacology, Mutation genetics, Pseudomonas aeruginosa genetics, Pseudomonas fluorescens genetics, RNA Polymerase Sigma 54 genetics, RNA Polymerase Sigma 54 metabolism, Species Specificity, Virulence genetics, Pseudomonas aeruginosa pathogenicity, Pseudomonas fluorescens pathogenicity
- Abstract
Some bacterial phenotypes measured in vitro can be used to access bacterial virulence, on the premise that they are positively correlated with data from in vivo experiments. We show here that in vitro assessment of bacterial phenotypes, such as adherence and cytotoxicity, are positively correlated with data from in vivo experiments in Drosophila and can be used to assess bacterial virulence in vivo. Manipulation of environmental parameters, such as iron availability, induced changes in the phenotypes measured in vitro that correlated with changes in vivo virulence of all strains tested. Applying these assays, we demonstrate the pathogenic potential of a Pseudomonas fluorescens strain, initially isolated as a non-pathogenic milk contaminant. This strain displayed adherence and cytotoxicity comparable to those of the Pseudomonas aeruginosa pathogenic strain PAK, and colonized the infected flies as rapidly as the PAK strain. These results indicate that this "a priori" non-pathogenic bacterium is capable of escaping the host immune response, supporting the use of in vitro tests for screening of potential pathogens.
- Published
- 2006
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23. Frequencies of phenylalanine hydroxylase mutations I65T, R252W, R261Q, R261X, IVS10nt11, V388M, R408W, Y414C, and IVS12nt1 in Minas Gerais, Brazil.
- Author
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Santos LL, Magalhães Mde C, Reis Ade O, Starling AL, Januário JN, Fonseca CG, Aguiar MJ, and Carvalho MR
- Subjects
- Brazil epidemiology, Electrophoresis, Polyacrylamide Gel, Genetic Testing, Humans, Infant, Newborn, Neonatal Screening, Phenylketonurias epidemiology, Mutation genetics, Phenylalanine Hydroxylase genetics, Phenylketonurias genetics
- Abstract
In order to determine the phenylketonuria (PKU) mutation spectrum in the population of Minas Gerais State, Brazil, 78 unrelated PKU patients found by the neonatal screening program from 1993 to 2003 were tested for nine phenylalanine hydroxylase mutations. These mutations were selected due to their high frequencies in other Brazilian populations and in Portugal, where the largest contingent of the Caucasian component of the Brazilian population originated from. The most frequent mutations were V388M (21%), R261Q (16%), IVS10nt11 (13.4%), I65T (5.7%), and R252W (5%). The frequencies of the other four mutations (R261X, R408W, Y414C, and IVS12nt1) did not reach 2%. By testing these nine mutations, we were able to identify 64% of the PKU alleles in our sample. V388M frequency was higher than in any other known population and almost three times larger than that observed in Portugal, probably reflecting genetic drift. The mutation profile, as well as the relative frequency of the different mutations, suggest that the Minas Gerais population more closely resembles that of Portugal than do the other Brazilian populations that have already been tested.
- Published
- 2006
24. Mutations in HlyD, part of the type 1 translocator for hemolysin secretion, affect the folding of the secreted toxin.
- Author
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Pimenta AL, Racher K, Jamieson L, Blight MA, and Holland IB
- Subjects
- Amino Acid Motifs, Amino Acid Substitution, Calcium, Escherichia coli genetics, Escherichia coli physiology, Escherichia coli Proteins chemistry, Escherichia coli Proteins genetics, Escherichia coli Proteins toxicity, Hemolysin Proteins, Membrane Transport Proteins genetics, Mutation, Missense, Point Mutation, Protein Transport, DNA Mutational Analysis, Escherichia coli chemistry, Escherichia coli Proteins metabolism, Escherichia coli Proteins physiology, Membrane Transport Proteins physiology, Protein Folding
- Abstract
HlyD, a member of the membrane fusion protein family, is essential for the secretion of the RTX hemolytic toxin HlyA from Escherichia coli. Random point mutations affecting HlyA secretion were obtained, distributed in most periplasmic regions of the HlyD molecule. Analysis of the secretion phenotypes of different mutants allowed the identification of regions in HlyD involved in different steps of HlyA translocation. Four mutants, V349-I, T85-I, V334-I and L165-Q, were conditionally defective, a phenotype shown to be linked to the presence of inhibitory concentrations of Ca2+ in extracellular medium. Hly mutant T85-I was defective at an early stage in secretion, while mutants V334-I and L165-Q appeared to accumulate HlyA in the cell envelope, indicating a block at an intermediate step. Mutants V349-I, V334-I, and L165-Q were only partially defective in secretion, allowing significant levels of HlyA to be transported, but in the case of V349-I and L165-Q the HlyA molecules secreted showed greatly reduced hemolytic activity. Hemolysin molecules secreted from V349-I and V334-I are defective in normal folding and can be reactivated in vitro to the same levels as HlyA secreted from the wild-type translocator. Both V349-I and V334-I mutations mapped to the C-terminal lipoyl repeat motif, involved in the switching from the helical hairpin to the extended form of HlyD during assembly of the functional transport channel. These results suggest that HlyD is an integral component of the transport pathway, whose integrity is essential for the final folding of secreted HlyA into its active form.
- Published
- 2005
- Full Text
- View/download PDF
25. [Utilization of community mental health services in the city of Santos, São Paulo, Brazil].
- Author
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Andreoli SB, Ronchetti Sde S, de Miranda AL, Bezerra CR, Magalhães CC, Martin D, and Pinto RM
- Subjects
- Adolescent, Adult, Aged, Aged, 80 and over, Brazil, Child, Child, Preschool, Female, Humans, Infant, Male, Middle Aged, Schizophrenia therapy, Community Mental Health Services statistics & numerical data, Mental Disorders therapy
- Abstract
To report on the clientele treated at community mental health services (CAPS) in the city of Santos, São Paulo, Brazil, a census was conducted of the patients examined at the services from June 1, 2001, to June 30, 2001. The patient's initial contact with the service was registered, and data were recorded on a standardized form, using the medical case history as a source of information. Among the 1,673 patients, average age was 46 years, 59.0% were female, 58.0% lived with their families, and mean duration of treatment was three years. Some 38.0% were schizophrenic, schizotypical, or in acute delusional states, 31.0% presented mood disorders, and 17.0% were neurotic. Treatment modalities included out-patient psychiatric (81.0%), individual (23.0%), group (13.0%), and psychosocial rehabilitation (4.3%). In Santos, CAPS treat all categories of mental disorders (and frequently those considered the most severe cases) expected at this type of service. The treatment model is that of an out-patient psychiatric clinic.
- Published
- 2004
- Full Text
- View/download PDF
26. Dermatitis in a dog associated with an unidentified Toxoplasma gondii-like parasite.
- Author
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Dubey JP, Pimenta AL, Abboud LC, Ravasani RR, and Mense M
- Subjects
- Animals, Dermatitis parasitology, Dermatitis pathology, Dog Diseases pathology, Dogs, Fatal Outcome, Female, Microscopy, Electron veterinary, Toxoplasma ultrastructure, Toxoplasmosis, Animal pathology, Dermatitis veterinary, Dog Diseases parasitology, Toxoplasma growth & development, Toxoplasmosis, Animal parasitology
- Abstract
Protozoal dermatitis was diagnosed in a 6-year-old female Great Dane dog from Rio de Janeiro, Brazil. The dog died because of a chronic illness with an Ehrlichia-like organism. Numerous apicomplexan parasites were identified histologically in the section of dermal lesions. The protozoan reacted with Toxoplasma gondii polyclonal rabbit serum but not with Neospora caninum or Sarcocystis neurona antibodies. Ultrastructurally, the protozoa was not T. gondii because it had schizont-like structures with merozoites arranged around a prominent residual body, and the merozoites had several rhoptries with electron-dense contents; rhoptries in T. gondii tachyzoites are electron-lucent and a residual body is not found in groups of tachyzoites. This is the first report of unidentified T. gondii-like protozoa in the skin of a dog.
- Published
- 2003
- Full Text
- View/download PDF
27. Porins of Pseudomonas fluorescens MFO as fibronectin-binding proteins.
- Author
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Rebière-Huët J, Guérillon J, Pimenta AL, Di Martino P, Orange N, and Hulen C
- Subjects
- Bacterial Adhesion, Blotting, Western, Porins genetics, Sequence Homology, Amino Acid, Bacterial Outer Membrane Proteins, Bacterial Proteins, Fibronectins metabolism, Porins metabolism, Pseudomonas fluorescens metabolism
- Abstract
Bacterial adherence is a complex phenomenon involving specific interactions between receptors, including matricial fibronectin, and bacterial ligands. We show here that fibronectin and outer membrane proteins of Pseudomonas fluorescens were able to inhibit adherence of P. fluorescens to fibronectin-coated wells. We identified at least six fibronectin-binding proteins with molecular masses of 70, 55, 44, 37, 32 and 28 kDa. The presence of native (32 kDa) and heat-modified forms (37 kDa) of OprF was revealed by immuno-analysis and the 44-kDa band was composed of three proteins, their N-terminal sequences showing homologies with Pseudomonas aeruginosa porins (OprD, OprE1 and OprE3).
- Published
- 2002
- Full Text
- View/download PDF
28. Antibody analysis of the localisation, expression and stability of HlyD, the MFP component of the E. coli haemolysin translocator.
- Author
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Pimenta AL, Young J, Holland IB, and Blight MA
- Subjects
- Bacterial Outer Membrane Proteins metabolism, Bacterial Proteins genetics, Bacterial Proteins immunology, Carrier Proteins genetics, Carrier Proteins immunology, Cell Division, Cell Fractionation, Cell Membrane immunology, Cell Membrane metabolism, Escherichia coli cytology, Escherichia coli genetics, Fluorescent Antibody Technique, Gene Deletion, Gene Expression, Gene Expression Regulation, Bacterial, Glutathione Transferase genetics, Half-Life, Membrane Proteins genetics, Membrane Proteins immunology, Mutation, Recombinant Fusion Proteins genetics, Subcellular Fractions immunology, Subcellular Fractions metabolism, Antibodies, Monoclonal immunology, Bacterial Proteins metabolism, Carrier Proteins metabolism, Escherichia coli metabolism, Escherichia coli Proteins, Hemolysin Proteins metabolism, Membrane Proteins metabolism, Membrane Transport Proteins
- Abstract
HlyD has a single transmembrane domain (residues 59-80) and a large periplasmic domain, and is essential for the secretion of haemolysin from Escherichia coli. Using an antibody raised against HlyD, the protein was localised to the cell envelope by immunofluorescence and to the cytoplasmic membrane by sucrose gradient analysis. We have examined the stability of this protein in the presence and absence of other putative components of the translocator, HlyB and TolC. HlyD is normally highly stable but in the absence of TolC, the steady-state level of HlyD is greatly reduced and the protein has a half-life at 37 degrees C of 36 min. In the absence of HlyB, HlyD is also unstable and specific degradation products are detected, which co-fractionate with the inner membrane, indicating in this case limited cleavage at specific sites. However, the effect of removing both HlyB and TolC is not additive. On the contrary, in the absence of both HlyB and TolC the half-life of HlyD is approximately 110 min. This result shows that in the presence of HlyB removal of TolC renders HlyD more unstable than it is in the absence of both HlyB and TolC. This suggests that the presence of HlyB induces a structural change in HlyD. In addition, HlyB itself appears to be less stable in the absence of HlyD. These results are consistent with an interaction between HlyD/TolC and HlyB/HlyD. A derivative of HlyD, HlyD22, lacking the 40 N-terminal residues of HlyD assembles into the inner membrane displaying the same stability with and without HlyB as wild type HlyD does. This N-terminal region therefore appears to play no role in stable localisation but is involved in secretion, since HlyD22 is completely secretion defective. Modification of the C-terminus on the other hand completely destabilised the molecule and HlyD was not detectable in the envelope. Secretion of active haemolysin is limited to a brief period during mid to late exponential phase. In contrast, HlyD is apparently synthesised constitutively throughout the growth phase, demonstrating that the production of this component of the translocator is not the limiting factor for growth phase-dependent secretion.
- Published
- 1999
- Full Text
- View/download PDF
29. Identification and preliminary characterization of temperature-sensitive mutations affecting HlyB, the translocator required for the secretion of haemolysin (HlyA) from Escherichia coli.
- Author
-
Blight MA, Pimenta AL, Lazzaroni JC, Dando C, Kotelevets L, Séror SJ, and Holland IB
- Subjects
- ATP-Binding Cassette Transporters metabolism, Adenosine Triphosphatases chemistry, Adenosine Triphosphatases metabolism, Amino Acid Sequence, Aspartic Acid genetics, Bacterial Proteins chemistry, Bacterial Proteins genetics, Base Sequence, Carrier Proteins chemistry, Carrier Proteins genetics, Carrier Proteins metabolism, Drug Resistance, Microbial genetics, Glycine genetics, Hemolysin Proteins chemistry, Hemolysin Proteins metabolism, Leucine genetics, Membrane Proteins chemistry, Membrane Proteins genetics, Molecular Sequence Data, Mutagenesis, Site-Directed, Point Mutation, Proline genetics, Recombinant Fusion Proteins, Repressor Proteins genetics, Sequence Alignment, Sequence Homology, Amino Acid, Signal Transduction genetics, Temperature, Vancomycin, Viral Proteins, Viral Regulatory and Accessory Proteins, ATP-Binding Cassette Transporters genetics, Adenosine Triphosphatases genetics, Bacterial Proteins metabolism, DNA-Binding Proteins, Escherichia coli genetics, Escherichia coli Proteins, Genes, Bacterial genetics, Hemolysin Proteins genetics
- Abstract
We have carried out a genetic analysis of Escherichia coli HlyB using in vitro(hydroxylamine) mutagenesis and regionally directed mutagenesis. From random mutagenesis, three mutants, temperature sensitive (Ts) for secretion, were isolated and the DNA sequenced: Gly10Arg close to the N-terminus, Gly408Asp in a highly conserved small periplasmic loop region PIV, and Pro624Leu in another highly conserved region, within the ATP-binding region. Despite the Ts character of the Gly10 substitution, a derivative of HlyB, in which the first 25 amino acids were replaced by 21 amino acids of the lambda Cro protein, was still active in secretion of HlyA. This indicates that this region of HlyB is dispensable for function. Interestingly, the Gly408Asp substitution was toxic at high temperature and this is the first reported example of a conditional lethal mutation in HlyB. We have isolated 4 additional mutations in PIV by directed mutagenesis, giving a total of 5 out of 12 residues substituted in this region, with 4 mutations rendering HlyB defective in secretion. The Pro624 mutation, close to the Walker B-site for ATP binding in the cytoplasmic domain is identical to a mutation in HisP that leads to uncoupling of ATP hydrolysis from the transport of histidine. The expression of a fully functional haemolysin translocation system comprising HlyC,A,B and D increases the sensitivity of E. coli to vancomycin 2.5-fold, compared with cells expressing HlyB and HlyD alone. Thus, active translocation of HlyA renders the cells hyperpermeable to the drug. Mutations in hlyB affecting secretion could be assigned to two classes: those that restore the level of vancomycin resistance to that of E. coli not secreting HlyA and those that still confer hypersensitivity to the drug in the presence of HlyA. We propose that mutations that promote vancomycin resistance will include mutations affecting initial recognition of the secretion signal and therefore activation of a functional transport channel. Mutations that do not alter HlyA-dependent vancomycin sensitivity may, in contrast, affect later steps in the transport process.
- Published
- 1994
- Full Text
- View/download PDF
30. Visceral toxoplasmosis in dogs from Brazil.
- Author
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Pimenta AL, Piza ET, Cardoso Júnior RB, and Dubey JP
- Subjects
- Animals, Brazil, Dog Diseases parasitology, Dogs, Intestinal Diseases, Parasitic parasitology, Intestinal Diseases, Parasitic pathology, Intestine, Small parasitology, Male, Toxoplasma isolation & purification, Toxoplasmosis, Animal parasitology, Viscera parasitology, Viscera pathology, Dog Diseases pathology, Intestinal Diseases, Parasitic veterinary, Intestine, Small pathology, Toxoplasmosis, Animal pathology
- Abstract
Toxoplasma gondii was identified in tissues of two dogs (3 and 10 months of age) from Brazil. Primary lesions consisted of necrotizing intestinal myositis associated with numerous tachyzoites. Parasites in tissues reacted with anti-T. gondii serum but not with Neospora caninum serum.
- Published
- 1993
- Full Text
- View/download PDF
31. [Contribution to the study of the "dumping syndrome"].
- Author
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TEIXEIRA AM, MARINHO L, and PIMENTA AL
- Subjects
- Humans, Dumping Syndrome
- Published
- 1962
32. [VECTORCARDIOGRAPHIC STUDY OF THE P WAVE PATTERN IN MITRAL VALVE DISEASES].
- Author
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PIMENTA AL, BRAGANCA-TENDER MJ, and MAGALHAES LS
- Subjects
- Humans, Heart Valve Diseases, Mitral Valve, Mitral Valve Insufficiency, Rheumatic Heart Disease, Vectorcardiography
- Published
- 1965
33. [Morphology of the P wave in mitral stenosis and insufficiency in relation to the radiological aspects of the auricles].
- Author
-
PIMENTA AL
- Subjects
- Humans, Disease, Electrocardiography, Heart Diseases, Heart Valve Diseases, Mitral Valve, Mitral Valve Stenosis, Rheumatic Heart Disease
- Published
- 1959
34. [The U wave in heart diseases (study of 1000 cases)].
- Author
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PIMENTA AL and XAVIER JB
- Subjects
- Brugada Syndrome, Cardiac Conduction System Disease, Humans, Arrhythmias, Cardiac, Coronary Disease diagnosis, Electrocardiography, Heart Conduction System, Heart Diseases physiology
- Published
- 1959
35. [Apropos of a case of abdominal aortic aneurysm with rupture into the left pleural cavity].
- Author
-
PIMENTA AL and CARDOSO V
- Subjects
- Humans, Rupture, Aortic Aneurysm complications, Aortic Aneurysm, Abdominal, Pleural Cavity
- Published
- 1959
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